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What type of wood did Edison use in his improved filament? | Thomas Edison began serious research into developing a practical incandescent lamp in 1878. Edison filed his first patent application for "Improvement In Electric Lights" on 14 October 1878. After many experiments, first with carbon in the early 1880s and then with platinum and other metals, in the end Edison returned to a carbon filament. The first successful test was on 22 October 1879, and lasted 13.5 hours. Edison continued to improve this design and by 4 November 1879, filed for a US patent for an electric lamp using "a carbon filament or strip coiled and connected ... to platina contact wires." Although the patent described several ways of creating the carbon filament including using "cotton and linen thread, wood splints, papers coiled in various ways," Edison and his team later discovered that a carbonized bamboo filament could last more than 1200 hours. In 1880, the Oregon Railroad and Navigation Company steamer, Columbia, became the first application for Edison's incandescent electric lamps (it was also the first ship to execute use of a dynamo). | During the late medieval period, cotton became known as an imported fiber in northern Europe, without any knowledge of how it was derived, other than that it was a plant. Because Herodotus had written in his Histories, Book III, 106, that in India trees grew in the wild producing wool, it was assumed that the plant was a tree, rather than a shrub. This aspect is retained in the name for cotton in several Germanic languages, such as German Baumwolle, which translates as "tree wool" (Baum means "tree"; Wolle means "wool"). Noting its similarities to wool, people in the region could only imagine that cotton must be produced by plant-borne sheep. John Mandeville, writing in 1350, stated as fact the now-preposterous belief: "There grew there [India] a wonderful tree which bore tiny lambs on the endes of its branches. These branches were so pliable that they bent down to allow the lambs to feed when they are hungrie [sic]." (See Vegetable Lamb of Tartary.) By the end of the 16th century, cotton was cultivated throughout the warmer regions in Asia and the Americas. | eng_Latn | 26,100 |
What is Tennessee's primary non-meat agricultural product? | Tennessee's major industries include agriculture, manufacturing, and tourism. Poultry, soybeans, and cattle are the state's primary agricultural products, and major manufacturing exports include chemicals, transportation equipment, and electrical equipment. The Great Smoky Mountains National Park, the nation's most visited national park, is headquartered in the eastern part of the state, and a section of the Appalachian Trail roughly follows the Tennessee-North Carolina border. Other major tourist attractions include the Tennessee Aquarium in Chattanooga; Dollywood in Pigeon Forge; the Parthenon, the Country Music Hall of Fame and Museum, and Ryman Auditorium in Nashville; the Jack Daniel's Distillery in Lynchburg; and Elvis Presley's Graceland residence and tomb, the Memphis Zoo, and the National Civil Rights Museum in Memphis. | During the late medieval period, cotton became known as an imported fiber in northern Europe, without any knowledge of how it was derived, other than that it was a plant. Because Herodotus had written in his Histories, Book III, 106, that in India trees grew in the wild producing wool, it was assumed that the plant was a tree, rather than a shrub. This aspect is retained in the name for cotton in several Germanic languages, such as German Baumwolle, which translates as "tree wool" (Baum means "tree"; Wolle means "wool"). Noting its similarities to wool, people in the region could only imagine that cotton must be produced by plant-borne sheep. John Mandeville, writing in 1350, stated as fact the now-preposterous belief: "There grew there [India] a wonderful tree which bore tiny lambs on the endes of its branches. These branches were so pliable that they bent down to allow the lambs to feed when they are hungrie [sic]." (See Vegetable Lamb of Tartary.) By the end of the 16th century, cotton was cultivated throughout the warmer regions in Asia and the Americas. | eng_Latn | 26,101 |
The film was tentatively titled `` Sivilized '' and was a modern version of Huckleberry Finn . | It was a modern version of Huckleberry Finn . | Eli Whitney ( December 8 , 1765 -- January 8 , 1825 ) was an American inventor . He is known as the inventor of the cotton gin , an important invention in the Industrial Revolution . | eng_Latn | 26,102 |
What is cotton gin? | Which task was performed by the cotton gin? | What were some of the most important inventions during the Industrial Revolution? | eng_Latn | 26,103 |
During what centuries did British rule effect Indian cotton production? | India's cotton-processing sector gradually declined during British expansion in India and the establishment of colonial rule during the late 18th and early 19th centuries. This was largely due to aggressive colonialist mercantile policies of the British East India Company, which made cotton processing and manufacturing workshops in India uncompetitive. Indian markets were increasingly forced to supply only raw cotton and, by British-imposed law, to purchase manufactured textiles from Britain.[citation needed] | Genetically modified (GM) cotton was developed to reduce the heavy reliance on pesticides. The bacterium Bacillus thuringiensis (Bt) naturally produces a chemical harmful only to a small fraction of insects, most notably the larvae of moths and butterflies, beetles, and flies, and harmless to other forms of life. The gene coding for Bt toxin has been inserted into cotton, causing cotton, called Bt cotton, to produce this natural insecticide in its tissues. In many regions, the main pests in commercial cotton are lepidopteran larvae, which are killed by the Bt protein in the transgenic cotton they eat. This eliminates the need to use large amounts of broad-spectrum insecticides to kill lepidopteran pests (some of which have developed pyrethroid resistance). This spares natural insect predators in the farm ecology and further contributes to noninsecticide pest management. | eng_Latn | 26,104 |
What was the problem with manufacturing the tungsten filament? | In 1906, the tungsten filament was introduced. Tungsten metal was initially not available in a form that allowed it to be drawn into fine wires. Filaments made from sintered tungsten powder were quite fragile. By 1910, a process was developed by William D. Coolidge at General Electric for production of a ductile form of tungsten. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and then wire drawing. It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million greatly improved the life and durability of the tungsten filaments. | A public genome sequencing effort of cotton was initiated in 2007 by a consortium of public researchers. They agreed on a strategy to sequence the genome of cultivated, tetraploid cotton. "Tetraploid" means that cultivated cotton actually has two separate genomes within its nucleus, referred to as the A and D genomes. The sequencing consortium first agreed to sequence the D-genome relative of cultivated cotton (G. raimondii, a wild Central American cotton species) because of its small size and limited number of repetitive elements. It is nearly one-third the number of bases of tetraploid cotton (AD), and each chromosome is only present once.[clarification needed] The A genome of G. arboreum would be sequenced next. Its genome is roughly twice the size of G. raimondii's. Part of the difference in size between the two genomes is the amplification of retrotransposons (GORGE). Once both diploid genomes are assembled, then research could begin sequencing the actual genomes of cultivated cotton varieties. This strategy is out of necessity; if one were to sequence the tetraploid genome without model diploid genomes, the euchromatic DNA sequences of the AD genomes would co-assemble and the repetitive elements of AD genomes would assembly independently into A and D sequences respectively. Then there would be no way to untangle the mess of AD sequences without comparing them to their diploid counterparts. | eng_Latn | 26,105 |
Who did a study in 2007 regarding the five countries with the highest rates of software piracy? | According to a 2007 BSA and International Data Corporation (IDC) study, the five countries with the highest rates of software piracy were: 1. Armenia (93%); 2. Bangladesh (92%); 3. Azerbaijan (92%); 4. Moldova (92%); and 5. Zimbabwe (91%). According to the study's results, the five countries with the lowest piracy rates were: 1. U.S. (20%); 2. Luxembourg (21%); 3. New Zealand (22%); 4. Japan (23%); and 5. Austria (25%). The 2007 report showed that the Asia-Pacific region was associated with the highest amount of loss, in terms of U.S. dollars, with $14,090,000, followed by the European Union, with a loss of $12,383,000; the lowest amount of U.S. dollars was lost in the Middle East/Africa region, where $2,446,000 was documented. | Beginning as a self-help program in the mid-1960s, the Cotton Research and Promotion Program (CRPP) was organized by U.S. cotton producers in response to cotton's steady decline in market share. At that time, producers voted to set up a per-bale assessment system to fund the program, with built-in safeguards to protect their investments. With the passage of the Cotton Research and Promotion Act of 1966, the program joined forces and began battling synthetic competitors and re-establishing markets for cotton. Today, the success of this program has made cotton the best-selling fiber in the U.S. and one of the best-selling fibers in the world.[citation needed] | eng_Latn | 26,106 |
what is gin made out of | Gin is a spirit flavored with juniper berries. Gin is usually made by the re-distillation of white grain spirit with the berries - though sometimes (compound gin) simply by flavouring the spirit with berries (and not re-distilling). Source(s): Wickipedia... hweaveriii · 10 years ago. | Gingham is a fabric made from dyed cotton yarn. The name is Indonesian in origin, assimilated into Dutch. When originally imported (in the 17th century), it was a striped fabric, but from the mid 18th century, when it was being produced in the mills of Manchester, England, it had become woven into checked or plaid patterns (often blue and white). | eng_Latn | 26,107 |
what year were bananas brought to the americas | A Brief History of Bananas. A Brief History. Bananas were originally found in South East Asia, mainly in India. They were brought west by Arab conquerors in 327 B.C. and moved from Asia Minor to Africa and finally carried to the New World by the first explorers and missionaries to the Caribbean. The mass production of bananas started in 1834 and really started exploding in the late 1880âs. 1 Before the 1870âs most of the land that bananas were grown on in the Caribbean had been previously used to grow sugar. | When Columbus discovered America in 1492, he found cotton growing in the Bahama Islands. By 1500, cotton was known generally throughout the world. Cotton seed are believed to have been planted in Florida in 1556 and in Virginia in 1607. By 1616, colonists were growing cotton along the James River in Virginia. | eng_Latn | 26,108 |
who made cotton candy first | History of Cotton Candy. Originally called Fairy Floss, the process of making Cotton Candy was invented by four men: Thomas Patton, Josef Delarose Lascaux, John C. Wharton, and William Morrison. | NECCO Wafers®. In 1847, a young English immigrant and progressive thinker, Oliver Chase, invented the first American candy machine, a lozenge cutter. After a period of initial success selling his exciting new candy, he joined forces with brother, Silas Edwin, and founded Chase and Company, the pioneer member of the NECCO family. | eng_Latn | 26,109 |
price of cotton seed | Table 1 provides assumed values for an average cotton crop including profit potential for cotton lint and cottonseed. For a field that produces 2,631 lbs of seed cotton/acre with 38% turnout, the field will produce approximately 1,000 lbs lint/acre. Assuming the seed cotton also has about 300 lbs of trash per acre about 1,331 lbs of fuzzy cottonseed is produced per acre. Cottonseed sold at $350/ton ($0.175/lb) will net $232.93/acre in this scenario. | The approximate yield of US alfalfa seed in 2005 was 135 million pounds, with average price of. $190 per 100 pounds of seed, thus the estimated value of alfalfa seed is $218.5 million. A. fringe benefit to the production of alfalfa seed is the production of honey from bees. In the. | eng_Latn | 26,110 |
how is cotton harmful to the soil? what was done to keep the earth usable? | It uses up all of the "nutrients" or whatever in the soil. Crop rotation and planting things like legumes were done to allow the land to recharge between planting cycles. | Would you be mad if your kid messed up a farm you gave him. Bet God's grounded in his bedroom by now. Ha | eng_Latn | 26,111 |
where was cotton first discovered | When Columbus discovered America in 1492, he found cotton growing in the Bahama Islands. By 1500, cotton was known generally throughout the world. Cotton seed are believed to have been planted in Florida in 1556 and in Virginia in 1607. | Arab merchants brought cotton cloth to Europe about 800 A.D. When Columbus discovered America in 1492, he found cotton growing in the Bahama Islands. By 1500, cotton was known generally throughout the world. Cotton seed are believed to have been planted in Florida in 1556 and in Virginia in 1607. | eng_Latn | 26,112 |
is cotton a raw material | Making the world better, one answer at a time. Cotton is a plant. The seeds of the plant are contained in a roundish pod called a boll, and surrounded by a fibrous material. When immature, the bolls are green, and the fibrous material is wet. As the bolls mature, they turn black/brown, the fibrous material swells, and the bolls split open, after which the fibrous material dries. This is raw cotton. | · There are no significant restrictions in trade in raw cotton. · Domestic support and export subsidies in major producing and exporting countries affect production and trade, and contributed to the lower world price over recent years. | eng_Latn | 26,113 |
what labor was used to create cotton | Cotton Campaign. The Cotton Campaign is a global coalition of human rights, labor, investor and business organizations dedicated to eradicating child labor and forced labor in cotton production. Our goals are to end the state systems of forced labor in Uzbekistan and Turkmenistanâs cotton sectors. | Two processes are necessary in the production of cotton goods from the raw material-spinning and weaving. At first, these were very much home-based, cottage industries. | eng_Latn | 26,114 |
what does supe | Supe is a fun messaging platform designed to reward those who create exciting and engaging content, whilst also allowing you to create and establish a closer relationship with your favourite social media influencers. | What's Supima. Founded in 1954, Supima is the promotional organization of the American Pima cotton growers. The Board of Directors of this non-profit organization is composed of Pima growers from the states of Arizona, California, New Mexico and Texas.Supimaâs primary objective is to promote the increased consumption of American Pima cotton around the world.Supima is a major sponsor of research programs to improve the quality of American Pima.Supima also works closely with cotton industry organizations and government agencies to ensure a fair and viable marketing environment for American Pima cotton growers.upima is a major sponsor of research programs to improve the quality of American Pima. Supima also works closely with cotton industry organizations and government agencies to ensure a fair and viable marketing environment for American Pima cotton growers. | eng_Latn | 26,115 |
how many pair of jean can one bale of cotton make | What can you make from a bale of cotton? One bale of cotton weighs about 480 pounds and is about the size of your refrigerator. From that bale, you can make: 215 Pairs of Jeans 409 Menâs Sport Shirts 690 Terry Bath Towels 765 Menâs Dress Shirts 1,217 Menâs T-shirts 3,085 Diapers 4,321 Mid-Calf Socks 313,600 $100 Bills | cotton gin can produce 60-100 cotton bales an hour A Australian cotton bale weighs 227kg (500 pounds)An Cottonseed represents approximately 50% of ginned | eng_Latn | 26,116 |
how is cotton traded | The importance of cotton in world trade Chapter 1 - The world cotton market - The importance of cotton in world trade. Cotton is essentially produced for its fibre, which is universally used as a textile raw material. Cotton is an important commodity in the world economy. Grown in more than 100 countries, cotton is a heavily traded agricultural commodity, with over 150 countries involved in exports or imports of cotton. | Free Cotton Futures Trading eGuide. September 21 st, 2015. Intercontinental Exchange ICE, +1.99% the leading global network of exchanges and clearing houses, announced that ICE Futures U.S. will launch a World Cotton contract on November 2, 2015. | eng_Latn | 26,117 |
where did the cotton plant originate | Cotton is believed to have originated from the Indus Valley Civilization, which a huge area of northwestern India and eastern Pakistan over 7000 years ago. In the Americas, co ⦠tton was first cultivated in Mexico some 8000 years ago. | Cotton grows from seeds of the cotton tree/plant/shrub-gossypium. The places it comes from include India, America, Africa, China, Brazil, Pakistan, Turkey. Cotton shrubs a ⦠re native to Tropical and SubTropical regions internationally.The varieties of the native American are: Gossypium Hirsutum and Gossypium barbadense.otton comes from a plant called cotton plant, The cotton must be plucked from its stalk, but be careful because it has prickles on the stalk. Once it has been picked it is ⦠then spun into yarn or thread. 2 people found this useful. | eng_Latn | 26,118 |
when is cotton harvested | Cotton is machine harvested in the U.S., beginning in July in south Texas and in October in more northern areas of the Belt. Stripper harvesters, used chiefly in Texas and Oklahoma, have rollers or mechanical brushes that remove the entire boll from the plant. In the rest of the Belt, spindle pickers are used. | When Europeans founded colonies in America they relied on cotton to make a living. In the early days, growing and harvesting cotton was a hard job that was done manually by slaves. In 1793 an American, Eli Whitney, invented the cotton gin, a machine that separated seeds from fiber. This new invention allowed farms to produce even more cotton. In the second part of the 20th century people started to produce synthetic fibers, like nylon and acrylic. The importance of cotton fiber began to drop. | eng_Latn | 26,119 |
`how round hay bales are formed | Large round hay bale mover. US 4348143 A. Abstract. A large round hay bale trailer having a fork lift cradle pivotally mounted on a two wheel trailer frame, the cradle being formed by pipe having 90° vertical and horizontal bends to provide fork, back support and horizontal connecting elements. | Haylage, also known as round bale silage, is another approach to preserving forage in eastern North Carolina.ow is Haylage Made? The forage is cut as if for hay-making but is baled at 50 â 60 percent moisture rather than at 18 â 20 percent moisture. Baling at the proper moisture content is the single most important variable. | eng_Latn | 26,120 |
what continent produces the best cotton | The US is the largest exporter of cotton with the continent of Africa coming a close second. This doesn't make it necesarily the best cotton, it makes it the most profitable and the most desired for the textile trade. | Cotton is a significant cash crop. According to the National Cotton Council of America, in 2014, China was the world's largest cotton-producing country with an estimated 100,991,000 480-pound bales. India was ranked second at 42,185,000 480-pound bales. | eng_Latn | 26,121 |
what does cottoning on mean | It seems that 'cotton to', 'cotton on to' all derive from the same root source, that is, the verb 'to cotton'. In the UK and its antipodes it has settled down as 'cotton on to', with the meaning 'form an understanding of' and in the USA it is 'cotton to', with the 'take a liking to' meaning. | Cotton is a natural fiber that is produced from the soft, fluffy substance that surrounds the seeds of the cotton plants. This substance is primarily made of cellulose. Cotton fabric is soft, light, breathable and ideal for warm weather. | eng_Latn | 26,122 |
The structure seen here is in this city, on the bluffs of the Mississippi | Randolph - Tennessee History for Kids There are four bluffs along the east side of the Mississippi River in what is ... Fort Prudhomme thus became the first structure built by whites in present-day West Tennessee. ... ventures was on the Fourth Chickasaw Bluff, where investors John Overton, ... Among the people who saw it from Randolph was Congressman David... | Which Fabrics Are Named After Cities? @ Super Beefy Jul 25, 2014 ... The cotton cloth called muslin was named after the city of Mosul, ... The fabric known as damask was named after the Syrian city of Damascus, and calico ... How Did Bolivia Get Its Name and Which Famous Person Is Bolivia... | eng_Latn | 26,123 |
what was the first state to be created from the louisiana purchase and admitted into the union? quizlet | The first officially sanctioned geographic and political limits associated with the Louisiana. Purchase were not laid down until the state of Louisiana was admitted to the union in 1812âthe. first state carved out of the Purchase as well as the first state west of the Mississippi. | With the acquisition of Louisiana, Jefferson nearly doubled the size of the fledgling U.S. and made it a world power. Later, 13 states or parts of states were carved out of the Louisiana Purchase territory. Through much of its early history Louisiana was a trading and financial center, and the fertility of its land made it one of the richest regions in America as first indigo then sugar and cotton rose to prominence in world markets. Many Louisiana planters were among the wealthiest men in America. | eng_Latn | 26,124 |
What business development did the British use to establish a hold on the global cotton market? | Production capacity in Britain and the United States was improved by the invention of the cotton gin by the American Eli Whitney in 1793. Before the development of cotton gins, the cotton fibers had to be pulled from the seeds tediously by hand. By the late 1700s a number of crude ginning machines had been developed. However, to produce a bale of cotton required over 600 hours of human labor, making large-scale production uneconomical in the United States, even with the use of humans as slave labor. The gin that Whitney manufactured (the Holmes design) reduced the hours down to just a dozen or so per bale. Although Whitney patented his own design for a cotton gin, he manufactured a prior design from Henry Odgen Holmes, for which Holmes filed a patent in 1796. Improving technology and increasing control of world markets allowed British traders to develop a commercial chain in which raw cotton fibers were (at first) purchased from colonial plantations, processed into cotton cloth in the mills of Lancashire, and then exported on British ships to captive colonial markets in West Africa, India, and China (via Shanghai and Hong Kong). | In the late 13th and early 14th centuries, a process took place – primarily in Italy but partly also in the Empire – that historians have termed a 'commercial revolution'. Among the innovations of the period were new forms of partnership and the issuing of insurance, both of which contributed to reducing the risk of commercial ventures; the bill of exchange and other forms of credit that circumvented the canonical laws for gentiles against usury, and eliminated the dangers of carrying bullion; and new forms of accounting, in particular double-entry bookkeeping, which allowed for better oversight and accuracy. | eng_Latn | 26,125 |
Why is cotton grown as an annual crop? | Successful cultivation of cotton requires a long frost-free period, plenty of sunshine, and a moderate rainfall, usually from 600 to 1,200 mm (24 to 47 in). Soils usually need to be fairly heavy, although the level of nutrients does not need to be exceptional. In general, these conditions are met within the seasonally dry tropics and subtropics in the Northern and Southern hemispheres, but a large proportion of the cotton grown today is cultivated in areas with less rainfall that obtain the water from irrigation. Production of the crop for a given year usually starts soon after harvesting the preceding autumn. Cotton is naturally a perennial but is grown as an annual to help control pests. Planting time in spring in the Northern hemisphere varies from the beginning of February to the beginning of June. The area of the United States known as the South Plains is the largest contiguous cotton-growing region in the world. While dryland (non-irrigated) cotton is successfully grown in this region, consistent yields are only produced with heavy reliance on irrigation water drawn from the Ogallala Aquifer. Since cotton is somewhat salt and drought tolerant, this makes it an attractive crop for arid and semiarid regions. As water resources get tighter around the world, economies that rely on it face difficulties and conflict, as well as potential environmental problems. For example, improper cropping and irrigation practices have led to desertification in areas of Uzbekistan, where cotton is a major export. In the days of the Soviet Union, the Aral Sea was tapped for agricultural irrigation, largely of cotton, and now salination is widespread. | With the help of Charles Stearn, an expert on vacuum pumps, in 1878, Swan developed a method of processing that avoided the early bulb blackening. This received a British Patent in 1880.[dubious – discuss] On 18 December 1878, a lamp using a slender carbon rod was shown at a meeting of the Newcastle Chemical Society, and Swan gave a working demonstration at their meeting on 17 January 1879. It was also shown to 700 who attended a meeting of the Literary and Philosophical Society of Newcastle upon Tyne on 3 February 1879. These lamps used a carbon rod from an arc lamp rather than a slender filament. Thus they had low resistance and required very large conductors to supply the necessary current, so they were not commercially practical, although they did furnish a demonstration of the possibilities of incandescent lighting with relatively high vacuum, a carbon conductor, and platinum lead-in wires. Besides requiring too much current for a central station electric system to be practical, they had a very short lifetime. Swan turned his attention to producing a better carbon filament and the means of attaching its ends. He devised a method of treating cotton to produce 'parchmentised thread' and obtained British Patent 4933 in 1880. From this year he began installing light bulbs in homes and landmarks in England. His house was the first in the world to be lit by a lightbulb and also the first house in the world to be lit by hydroelectric power. In 1878 the home of Lord Armstrong at Cragside was also among the first houses to be lit by electricity. In the early 1880s he had started his company. In 1881, the Savoy Theatre in the City of Westminster, London was lit by Swan incandescent lightbulbs, which was the first theatre, and the first public building in the world, to be lit entirely by electricity. | eng_Latn | 26,126 |
What did child do in textile mills in the US? | In 1910, over 2 million children in the same age group were employed in the United States. This included children who rolled cigarettes, engaged in factory work, worked as bobbin doffers in textile mills, worked in coal mines and were employed in canneries. Lewis Hine's photographs of child labourers in the 1910s powerfully evoked the plight of working children in the American south. Hines took these photographs between 1908 and 1917 as the staff photographer for the National Child Labor Committee. | In 1906, the tungsten filament was introduced. Tungsten metal was initially not available in a form that allowed it to be drawn into fine wires. Filaments made from sintered tungsten powder were quite fragile. By 1910, a process was developed by William D. Coolidge at General Electric for production of a ductile form of tungsten. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and then wire drawing. It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million greatly improved the life and durability of the tungsten filaments. | eng_Latn | 26,127 |
Accounting for half of all U.S. exports in 1855, this crop was "King" | Economy of the Confederate States of America - Wikipedia The Confederate States of America had an agrarian-based economy that relied heavily on slave-worked plantations for the production of cotton for export to Europe and the northern US states. ..... Cotton was the primary potential export, accounting for 75 percent of Southern goods either shipped to northern US states or... | This question originally aired on September 10,... | Jeopardy ... ... 1998 Category: MUSEUMS Question: This railroad's museum in Omaha has a tea set from Lincoln's private car & a replica of the Golden Spike Answer: Union. | eng_Latn | 26,128 |
What was the percentage of GM cotton planted in India in 2011? | GM cotton acreage in India grew at a rapid rate, increasing from 50,000 hectares in 2002 to 10.6 million hectares in 2011. The total cotton area in India was 12.1 million hectares in 2011, so GM cotton was grown on 88% of the cotton area. This made India the country with the largest area of GM cotton in the world. A long-term study on the economic impacts of Bt cotton in India, published in the Journal PNAS in 2012, showed that Bt cotton has increased yields, profits, and living standards of smallholder farmers. The U.S. GM cotton crop was 4.0 million hectares in 2011 the second largest area in the world, the Chinese GM cotton crop was third largest by area with 3.9 million hectares and Pakistan had the fourth largest GM cotton crop area of 2.6 million hectares in 2011. The initial introduction of GM cotton proved to be a success in Australia – the yields were equivalent to the non-transgenic varieties and the crop used much less pesticide to produce (85% reduction). The subsequent introduction of a second variety of GM cotton led to increases in GM cotton production until 95% of the Australian cotton crop was GM in 2009 making Australia the country with the fifth largest GM cotton crop in the world. Other GM cotton growing countries in 2011 were Argentina, Myanmar, Burkina Faso, Brazil, Mexico, Colombia, South Africa and Costa Rica. | During the time between 800 and 200 BCE the Shramana-movement formed, from which originated Jainism and Buddhism. In the same period the first Upanishads were written. After 500 BCE, the so-called "Second urbanization" started, with new urban settlements arising at the Ganges plain, especially the Central Ganges plain. The Central Ganges Plain, where Magadha gained prominence, forming the base of the Mauryan Empire, was a distinct cultural area, with new states arising after 500 BC[web 1] during the so-called "Second urbanization".[note 3] It was influenced by the Vedic culture, but differed markedly from the Kuru-Panchala region. It "was the area of the earliest known cultivation of rice in South Asia and by 1800 BC was the location of an advanced neolithic population associated with the sites of Chirand and Chechar". In this region the Shramanic movements flourished, and Jainism and Buddhism originated. | eng_Latn | 26,129 |
In what city did Horne begin their operations? | In 1849, Horne's began operations and soon became a leading Pittsburgh department store. In 1879, it opened a seven-story landmark which was the first department store in the city's downtown. In 1972, Associated Dry Goods acquired Horne's, and ADG expanded operations of Horne's to several stores in suburban malls throughout the Pittsburgh region as well as in Erie, Pennsylvania and Northeast Ohio. In December 1986, Horne's was acquired by a local investor group following ADG's acquisition by May Department Stores. By 1994, Federated Department Stores acquired the remaining ten Horne's stores and merged them with its Lazarus division, completely ceasing all operations of any store under the Horne's name. | Production capacity in Britain and the United States was improved by the invention of the cotton gin by the American Eli Whitney in 1793. Before the development of cotton gins, the cotton fibers had to be pulled from the seeds tediously by hand. By the late 1700s a number of crude ginning machines had been developed. However, to produce a bale of cotton required over 600 hours of human labor, making large-scale production uneconomical in the United States, even with the use of humans as slave labor. The gin that Whitney manufactured (the Holmes design) reduced the hours down to just a dozen or so per bale. Although Whitney patented his own design for a cotton gin, he manufactured a prior design from Henry Odgen Holmes, for which Holmes filed a patent in 1796. Improving technology and increasing control of world markets allowed British traders to develop a commercial chain in which raw cotton fibers were (at first) purchased from colonial plantations, processed into cotton cloth in the mills of Lancashire, and then exported on British ships to captive colonial markets in West Africa, India, and China (via Shanghai and Hong Kong). | eng_Latn | 26,130 |
To what date has cotton been dated? | The fiber is most often spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated from 5000 BC have been excavated in Mexico and the Indus Valley Civilization in Ancient India (modern-day Pakistan and some parts of India). Although cultivated since antiquity, it was the invention of the cotton gin that lowered the cost of production that led to its widespread use, and it is the most widely used natural fiber cloth in clothing today. | The 1850 census saw a dramatic shift in the way information about residents was collected. For the first time, free persons were listed individually instead of by head of household. There were two questionnaires: one for free inhabitants and one for slaves. The question on the free inhabitants schedule about color was a column that was to be left blank if a person was white, marked "B" if a person was black, and marked "M" if a person was mulatto. Slaves were listed by owner, and classified by gender and age, not individually, and the question about color was a column that was to be marked with a "B" if the slave was black and an "M" if mulatto. | eng_Latn | 26,131 |
Where was the expansion of cotton and agriculture mainly? | In 1924, the Tajik Autonomous Soviet Socialist Republic was created as a part of Uzbekistan, but in 1929 the Tajik Soviet Socialist Republic (Tajik SSR) was made a separate constituent republic, however the predominantly ethnic Tajik cities of Samarkand and Bukhara remained in the Uzbek SSR. Between 1927 and 1934, collectivization of agriculture and a rapid expansion of cotton production took place, especially in the southern region. Soviet collectivization policy brought violence against peasants and forced resettlement occurred throughout Tajikistan. Consequently, some peasants fought collectivization and revived the Basmachi movement. Some small scale industrial development also occurred during this time along with the expansion of irrigation infrastructure. | In 1864, Andrew Johnson (a War Democrat from Tennessee) was elected Vice President under Abraham Lincoln. He became President after Lincoln's assassination in 1865. Under Johnson's lenient re-admission policy, Tennessee was the first of the seceding states to have its elected members readmitted to the U.S. Congress, on July 24, 1866. Because Tennessee had ratified the Fourteenth Amendment, it was the only one of the formerly secessionist states that did not have a military governor during the Reconstruction period. | eng_Latn | 26,132 |
Where was the Wettin dynasty from? | Thuringia became a landgraviate in 1130 AD. After the extinction of the reigning Ludowingian line of counts and landgraves in 1247 and the War of the Thuringian Succession (1247–1264), the western half became independent under the name of "Hesse", never to become a part of Thuringia again. Most of the remaining Thuringia came under the rule of the Wettin dynasty of the nearby Margraviate of Meissen, the nucleus of the later Electorate and Kingdom of Saxony. With the division of the house of Wettin in 1485, Thuringia went to the senior Ernestine branch of the family, which subsequently subdivided the area into a number of smaller states, according to the Saxon tradition of dividing inheritance amongst male heirs. These were the "Saxon duchies", consisting, among others, of the states of Saxe-Weimar, Saxe-Eisenach, Saxe-Jena, Saxe-Meiningen, Saxe-Altenburg, Saxe-Coburg, and Saxe-Gotha; Thuringia became merely a geographical concept. | Production capacity in Britain and the United States was improved by the invention of the cotton gin by the American Eli Whitney in 1793. Before the development of cotton gins, the cotton fibers had to be pulled from the seeds tediously by hand. By the late 1700s a number of crude ginning machines had been developed. However, to produce a bale of cotton required over 600 hours of human labor, making large-scale production uneconomical in the United States, even with the use of humans as slave labor. The gin that Whitney manufactured (the Holmes design) reduced the hours down to just a dozen or so per bale. Although Whitney patented his own design for a cotton gin, he manufactured a prior design from Henry Odgen Holmes, for which Holmes filed a patent in 1796. Improving technology and increasing control of world markets allowed British traders to develop a commercial chain in which raw cotton fibers were (at first) purchased from colonial plantations, processed into cotton cloth in the mills of Lancashire, and then exported on British ships to captive colonial markets in West Africa, India, and China (via Shanghai and Hong Kong). | eng_Latn | 26,133 |
Who helped Bell investigate hydrofoils in 1908? | The March 1906 Scientific American article by American pioneer William E. Meacham explained the basic principle of hydrofoils and hydroplanes. Bell considered the invention of the hydroplane as a very significant achievement. Based on information gained from that article he began to sketch concepts of what is now called a hydrofoil boat. Bell and assistant Frederick W. "Casey" Baldwin began hydrofoil experimentation in the summer of 1908 as a possible aid to airplane takeoff from water. Baldwin studied the work of the Italian inventor Enrico Forlanini and began testing models. This led him and Bell to the development of practical hydrofoil watercraft. | Production capacity in Britain and the United States was improved by the invention of the cotton gin by the American Eli Whitney in 1793. Before the development of cotton gins, the cotton fibers had to be pulled from the seeds tediously by hand. By the late 1700s a number of crude ginning machines had been developed. However, to produce a bale of cotton required over 600 hours of human labor, making large-scale production uneconomical in the United States, even with the use of humans as slave labor. The gin that Whitney manufactured (the Holmes design) reduced the hours down to just a dozen or so per bale. Although Whitney patented his own design for a cotton gin, he manufactured a prior design from Henry Odgen Holmes, for which Holmes filed a patent in 1796. Improving technology and increasing control of world markets allowed British traders to develop a commercial chain in which raw cotton fibers were (at first) purchased from colonial plantations, processed into cotton cloth in the mills of Lancashire, and then exported on British ships to captive colonial markets in West Africa, India, and China (via Shanghai and Hong Kong). | eng_Latn | 26,134 |
What British business's policies damaged the Indian cotton industry? | India's cotton-processing sector gradually declined during British expansion in India and the establishment of colonial rule during the late 18th and early 19th centuries. This was largely due to aggressive colonialist mercantile policies of the British East India Company, which made cotton processing and manufacturing workshops in India uncompetitive. Indian markets were increasingly forced to supply only raw cotton and, by British-imposed law, to purchase manufactured textiles from Britain.[citation needed] | In the 17th century, the Somers Isles Company suppressed shipbuilding, as it needed Bermudians to farm to generate income from the land. Agricultural production met with limited success, however. The Bermuda cedar boxes used to ship tobacco to England were reportedly worth more than their contents.[citation needed] The colony of Virginia far surpassed Bermuda in both quality and quantity of tobacco produced. Bermudians began to turn to maritime trades relatively early in the 17th century, but the Somers Isles Company used all its authority to suppress turning away from agriculture. This interference led to the islanders demanding, and receiving, the revocation of the Company's charter in 1684, and the Company was dissolved. | eng_Latn | 26,135 |
What is the benefit of this formation type? | However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element. | The value of the deposit was obvious from the start, but the means of extracting the bitumen were not. The nearest town, Fort McMurray, Alberta was a small fur trading post, other markets were far away, and transportation costs were too high to ship the raw bituminous sand for paving. In 1915, Sidney Ells of the Federal Mines Branch experimented with separation techniques and used the bitumen to pave 600 feet of road in Edmonton, Alberta. Other roads in Alberta were paved with oil sands, but it was generally not economic. During the 1920s Dr. Karl A. Clark of the Alberta Research Council patented a hot water oil separation process and entrepreneur Robert C. Fitzsimmons built the Bitumount oil separation plant, which between 1925 and 1958 produced up to 300 barrels (50 m3) per day of bitumen using Dr. Clark's method. Most of the bitumen was used for waterproofing roofs, but other uses included fuels, lubrication oils, printers ink, medicines, rust and acid-proof paints, fireproof roofing, street paving, patent leather, and fence post preservatives. Eventually Fitzsimmons ran out of money and the plant was taken over by the Alberta government. Today the Bitumount plant is a Provincial Historic Site. | eng_Latn | 26,136 |
explain the impact of Eli's cotton gin on the price of the cotton goods and the price of woolen goods? | Before the cotton gin, it was time consuming to hand-pick all the seeds from the cotton. This made cotton more expensive than wool. The cotton gin could do the work of many people so the price of cotton fell as the supply grew.\nIt also had a lot to do with the demise of commercial hemp production in America if I remember right | Do one for Because of Winn-Dixie! It's one of my favorite books. You could do the scene where Winn-Dixie and Opal come to the pet store and Otis is playing his guitar and all the pets are still and quiet and then they go crazy!\n\nI'm not going to write it for you, but here's how it could start:\n\nOPAL: "Well, it's our first day working for Otis, Winn-Dixie. Let's go to the pet store."\nWINN-DIXIE: "Woof!"\nOPAL: (whistles as they walk to the pet store) Here we are!\n(Otis is playing the guitar. The animals are spellbound.)\n\nYou write the rest! | eng_Latn | 26,137 |
What are the two types of the cotton gin? | one cotton gin that was used in the US was based on the Indian charkha, which is for long-staple cotton.\n\nthe other is the one Eli Whitney invented called a saw gin. It is used for short-staple and medium-staple cotton. | Google it.\nDon't ask us to do your basic research.\nAnd ditto that if you're writing an essay, you should know this. If you have a text book, read it. | eng_Latn | 26,138 |
What does a cotton gin do? | What is the cotton gin and how does it work? | Are there different types of cotton? | eng_Latn | 26,139 |
when was the first successful textile mill based | the first successful mechanized textile mill was estabilished in mumbai in 1854. justify the statement giving four reasons. please i need this answer i have a exam tomorrow!! Share with your friends | the first successful mechanized textile mill was estabilished in mumbai in 1854. justify the statement giving four reasons. please i need this answer i have a exam tomorrow!! Share with your friends | eng_Latn | 26,140 |
who used cotton gins | Introduction. In 1794, U.S.-born inventor Eli Whitney (1765-1825) patented the cotton gin, a machine that revolutionized the production of cotton by greatly speeding up the process of removing seeds from cotton fiber. By the mid-19th century, cotton had become Americaâs leading export. | Background: The cotton gin is a machine designed to remove cotton from its seeds. The process uses a small screen and pulling hooks to force the cotton through the screen. It was invented by Eli Whitney on March 14, 1794, one of the many inventions that occurred during the American Industrial Revolution. However, earlier versions of the cotton gin had existed since the first century. It was improved over time from a single roller design to a double roller machine. | eng_Latn | 26,141 |
who began american spinning mill | Spinning mills were introduced to the United States in 1790 by English-born mechinist and businessman Samuel Slater (1768â1835). The twenty-one year old had worked as a textile laborer for more than six years in an English mill, where he learned about the workings of a cotton-spinning machine invented (1783) by Richard Arkwright (1732â92). | The first factory in the United States was begun after George Washington became President. In 1790, Samuel Slater, a cotton spinner's apprentice who left England the year before with the secrets of textile machinery, built a factory from memory to produce spindles of yarn.rom these humble beginnings to the time of the Civil War there were over two million spindles in over 1200 cotton factories and 1500 woolen factories in the United States. Dear Father, I received your letter on Thursday the 14th with much pleasure. I am well, which is one comfort. | eng_Latn | 26,142 |
what year was the cotton gin invented | Invented in year : 1793. A Cotton Gin is a machine that quickly and easily separates the cotton fibres from the seeds. The word 'Gin' is short for 'Engine'. The Cotton Gin was a wooden drum stuck with hooks which pulled the cotton fibres through a mesh. The cotton seeds would not fit through the mesh and fell outside. | 1 Letter from Eli Whitney to his Father regarding his invention of the cotton gin, September 11, 1793. 2 Letter from Thomas Jefferson to Eli Whitney, Jr. regarding his cotton gin patent, November 16, 1793. 3 Obituary for Eli Whitney, in Niles Weekly Register, January 25, 1825. | eng_Latn | 26,143 |
who built the first mill in the us | Paper is made at a paper mill. The first paper mills were built in China more than 2,000 years ago. Workers shredded recycled (used) rags and cloth to make paper. In 1690, William Rittenhouse built the first paper mill in the United States. American mills soon began making paper using the fiber from trees instead of old cloth. In addition to wood fiber, modern mills use recovered paper and wood chips to make paper. Recycling has always been part of papermaking. Recycling refers to the process of using old | Samuel Slater and the Slater Mill Historic Site. Samuel Slater is sometimes called the Father of the American Industrial Revolution, because he was responsible for the first American-built textile milling machinery in Rhode Island. Now the mill he built is a museum dedicated to the history of textile manufacture. | eng_Latn | 26,144 |
when were water mills mostly built | Early water mills were mostly used for grinding corn, then from the 13th century for a variety of other purposes, especially for âfullingâ or thickening woollen cloth.There was a dramatic growth in the number of mills in the late 18th and early 19th century.A growing population and the rise of the cotton industry meant an increased demand for water power. The new mills were built for cotton spinning and later adapted for other textile processes.arly water mills were mostly used for grinding corn, then from the 13th century for a variety of other purposes, especially for âfullingâ or thickening woollen cloth. | A large part of the process happens in a cotton mill. The first American cotton mill began operation on December 20, 1790. The mill in Pawtucket, Rhode Island, had water-powered machinery for carding and spinning cotton. A machine cards cotton by combing and untangling fibers while removing short undesirable fibers. | eng_Latn | 26,145 |
why should the cotton gin be important | A Revolutionary Invention. The cotton gin is a machine that separates cotton seeds from cotton fiber. Invented by Eli Whitney in 1793, it was an important invention because it dramatically reduced the amount of time it took to separate cotton seeds from cotton fiber. Prior to Whitney's invention, cotton seeds had to be removed by hand or with other primitive tools, making it a tedious and time consuming process. | However, like many inventors, Whitney (who died in 1825) could not have foreseen the ways in which his invention would change society for the worse. The most significant of these was the growth of slavery. While it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton. In fact, the opposite occurred. Cotton growing became so profitable for the planters that it greatly increased their demand for both land and slave labor. | eng_Latn | 26,146 |
when did the first factories take place | The First American Factories. Slater Mill, founded in 1793 by Samuel Slater, is now used as a museum dedicated to textile manufacturing. There was more than one kind of frontier and one kind of pioneer in early America.rom these humble beginnings to the time of the Civil War there were over two million spindles in over 1200 cotton factories and 1500 woolen factories in the United States. Dear Father, I received your letter on Thursday the 14th with much pleasure. I am well, which is one comfort. | THE first industrial revolution began in Britain in the late 18th century, with the mechanisation of the textile industry. Tasks previously done laboriously by hand in hundreds of weavers' cottages were brought together in a single cotton mill, and the factory was born. | eng_Latn | 26,147 |
which states made up the cotton kingdom | Once confined to the pre-Civil War South, the Cotton Belt was pushed west after the war. Today it extends primarily through North and South Carolina, Georgia, Alabama, Mississippi, western Tennessee, eastern Arkansas, Louisiana, eastern Texas, and southern Oklahoma. in United States: The Atlantic Plain. | The seven states that broke away from the Union to form the Confederacy â South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas â all belonged to the slave states: large-scale cotton producers who relied on the labour of slaves for their success. | eng_Latn | 26,148 |
what colony produced iron | They produced flour from the wheat they grew and sold it in other colonies or to Europe. These colonies were part agriculture and part industrial. Factories in Maryland produced iron and paper, textiles were produced in Pennsylvania factories. Lumber and shipbuilding industries also had success her. | In the 18th century, innovations like steamboats, railroads, and guns increased demand for wrought iron and steel. The Mount Savage Iron Works in Maryland was the largest in the United States in the late 1840s, and the first in the nation to produce heavy rails for the construction of railroads. | eng_Latn | 26,149 |
what manufacturing practice did eli whitney introduce | In popular mythology, Eli Whitney has been deemed the father of American technology, for two innovations: the cotton gin, and the idea of using interchangeable parts. Young Entrepreneur Eli Whitney was born in 1765 and grew up on a Massachusetts farm. During the Revolutionary War he manufactured nails to fill the demand caused by British embargos. Young Eli quickly learned how the marketplace worked, and diversified into hatpins and canes. | The market revolution brought about technological change that advanced the United Statesâ systems of manufacturing and commerce, and more northern states shifted their focus from agriculture and slave-labor to capitalist wage-labor and factory manufacturing. However, when Eli Whitney introduced the cotton-gin, the south only became more dependent on slave-labor to cultivate the crop that accounted for the majority of its economic profit. 1 This is a picture of a real cotton gin, designed by Eli Whitney in 1793. They quickly and easily separated the seeds from the cotton exponentially increasing cotton cultivation. In his 1857 publication, Cannibals All! | eng_Latn | 26,150 |
when was orr cotton mill build | The Marshall Orr House was built in 1885 by Dr. Samuel Marshall Orr, as a smaller replica of the home of his father, Governor James L. Orr. Gov. Orr's home, known locally as Forest Home and Arlington was demolished in 1956. A physician in Anderson for 35 years, Dr. Orr owned a pharmacy, was involved with Anderson's first building and loan association and served as vice-president of the Farmers and Merchants Bank. In the community, he served as a trustee of Anderson schools and was a vestryman of Grace Episcopal Church for twenty years. | The Alpha Cotton Mill, the Ada Cotton Mill, and the Victor Cotton Mill The Alpha Mill The Orient (Alpha) Mill Village A major expansion of the industrial base of Charlotte, N.C., occurred in 1888-89. Three cotton mills were organized and placed into production. All were erected by the D. A. Tompkins Co. | eng_Latn | 26,151 |
when was the cotton gin created | The modern mechanical cotton gin was invented in the United States of America in 1793 by Eli Whitney (1765â1825). Whitney applied for a patent on October 28, 1793; the patent was granted on March 14, 1794, but was not validated until 1807.Whitney's patent was assigned patent number 72X.lthough simple handheld roller gins have been used in India and other countries since at least 500 AD, the first modern mechanical cotton gin was created by U.S.American inventor Eli Whitney in 1793 and patented in 1794. | The modern mechanical cotton gin was invented in the United States of America in 1793 by Eli Whitney (1765â1825). Whitney applied for a patent on October 28, 1793; the patent was granted on March 14, 1794, but was not validated until 1807.Whitney's patent was assigned patent number 72X.he modern mechanical cotton gin was invented in the United States of America in 1793 by Eli Whitney (1765â1825). Whitney applied for a patent on October 28, 1793; the patent was granted on March 14, 1794, but was not validated until 1807. | eng_Latn | 26,152 |
when was benepay technologies established | The company was formerly known as Lyceum Business Services, LLC and changed its name to Benepay Technologies, LLC in June 2004. Benepay Technologies, LLC was founded in 2003 and is based in Gaithersburg, Maryland. It has locations in Clearwater, Florida; Wixom, Michigan; Plano, Texas. The company also has sales offices in Baltimore, Maryland; Columbus, Ohio; and Morristown, New York. Detailed Description. 18310 Montgomery Village Avenue. | Berkshire Hathaway traces its roots to a textile manufacturing company established by Oliver Chace in 1839 as the Valley Falls Company in Valley Falls, Rhode Island. Chace had previously worked for Samuel Slater, the founder of the first successful textile mill in America. Chace founded his first textile mill in 1806. | eng_Latn | 26,153 |
was the cotton gin steam powered | Horse and mule powers were eventually tried, which raised the daily output per gin to 400 pounds. It was soon found, however, that three men and a steam-powered gin could turn out approximately 4,000 pounds of clean cotton each day. Steam power was also ideal for driving large presses that made big cotton bales. In 1839, a Louisiana plantation owner wrote Very much (pleased) with Wm. | Invented in year : 1793. A Cotton Gin is a machine that quickly and easily separates the cotton fibres from the seeds. The word 'Gin' is short for 'Engine'. The Cotton Gin was a wooden drum stuck with hooks which pulled the cotton fibres through a mesh. The cotton seeds would not fit through the mesh and fell outside. | eng_Latn | 26,154 |
when did the united states began industrializing | The industrial growth that began in the United States in the early 1800's continued steadily up to and through the American Civil War. Still, by the end of the war, the typical American industry was small.ore than 25 million immigrants entered the United States between 1870 and 1916. Immigration plus natural growth caused the U.S. population to more than double during the same period, rising from about 40 million to about 100 million. Distribution and communication. | The Industrial Revolution began in England in the middle of the 18th century and spread to the rest of Europe and the United States in the early 19 th century. | eng_Latn | 26,155 |
what crops became the main crop produced in the antebellum south? | By the time of the American Revolution, settlers were exporting 66 million pounds of rice a year. Indigo became South Carolinaâs second most important early crop. Indigo production merged nicely with rice production on many plantations. But when that market dried up, planters shifted to cotton. | Cotton farming dominated Georgia's antebellum economy, but by the mid-1830s declining prices fueled by overproduction led some to seek alternatives to agriculture's boom-and-bust cycles. Industrial development offered one such alternative, and a flurry of investment enabled a number of nascent industries to appear throughout the state. | eng_Latn | 26,156 |
why was the cotton gin an important invention | Rating Newest Oldest. Best Answer: The cotton gin was so important because it changed the way the South produced their most profitable material, cotton. With the success of the cotton gin, it was easy to make bundles of cotton in short amounts of time. This helped increase trading and the Souths' economy. | Travel and History Blog. Share. The cotton engine or gin was the device invented by Eli Whitney in 1793 for the purpose of removing seeds from the cotton fiber. Widespread use of this machine created a cash crop for the South and revived the institution of slavery. | eng_Latn | 26,157 |
Before the use of the cotton gin, how was cotton separated? | Production capacity in Britain and the United States was improved by the invention of the cotton gin by the American Eli Whitney in 1793. Before the development of cotton gins, the cotton fibers had to be pulled from the seeds tediously by hand. By the late 1700s a number of crude ginning machines had been developed. However, to produce a bale of cotton required over 600 hours of human labor, making large-scale production uneconomical in the United States, even with the use of humans as slave labor. The gin that Whitney manufactured (the Holmes design) reduced the hours down to just a dozen or so per bale. Although Whitney patented his own design for a cotton gin, he manufactured a prior design from Henry Odgen Holmes, for which Holmes filed a patent in 1796. Improving technology and increasing control of world markets allowed British traders to develop a commercial chain in which raw cotton fibers were (at first) purchased from colonial plantations, processed into cotton cloth in the mills of Lancashire, and then exported on British ships to captive colonial markets in West Africa, India, and China (via Shanghai and Hong Kong). | The newly invented Western Electric moving coil or dynamic microphone was part of the Wide Range System. It had a flatter audio response than the old style Wente condenser type and didn't require electronics installed in the microphone housing. Signals fed to the cutting head were pre-emphasized in the treble region to help override noise in playback. Groove cuts in the vertical plane were employed rather than the usual lateral cuts. The chief advantage claimed was more grooves per inch that could be crowded together, resulting in longer playback time. Additionally, the problem of inner groove distortion, which plagued lateral cuts, could be avoided with the vertical cut system. Wax masters were made by flowing heated wax over a hot metal disc thus avoiding the microscopic irregularities of cast blocks of wax and the necessity of planing and polishing. | eng_Latn | 26,158 |
The pre-calling period (PCP), between emergence and first release of pheromone, determines the number of nights over which female Mythimna separata (Walker) (Lepidoptera: Noctuidae) can express their migratory potential. In its seasonal migrations in eastern Asia, this armyworm penetrates to latitudes at which it is unable to over-winter but at which reliable photoperiodic and temperature cues anticipate the deterioration of conditions. The effect of these environmental factors on PCP was examined in moths descended from samples collected in Nanjing (32oN) during the summer migration. Under LD 14:10h, a reduction in temperature, from 23oC during larval development to 18oC from 24 h after pupation, resulted in a twofold increase in PCP compared with insects held at 23oC. At 23oC, short days (LD 12:12 h) extended PCP but the magnitude of the response was increased under a regime of decreasing photoperiod, from LD 15:9h, to LD 12:12 h through larval, pupal and adult development. Further experiments demonstrated that the response depended on a decrease in photoperiod from pre-pupal stage to adult emergence (the pupal period is spent below ground). A reduction of 50–60min over the 13–15 day pupal period at 23oC was effective. The significance of decreasing photoperiods, irrespective of absolute levels, as a cue for species whose migrations traverse substantial ranges of latitude is considered and the results are discussed in relation to the genetic determination of PCP in M.separata and to its seasonal migrations in eastern China. | The effects of pupal period and age on calling behavior of virgin females of Pseudaletia sequax were determined. Calling behavior of groups of females of similar age of pupation was observed every 10 min for six calling days. Females were considered calling when they assumed a characteristic position: wings and abdomen elevated, displaying the ovipositor and presumably releasing pheromone. Calling behavior was discontinuous. Females with a shorter pupal period took more time to start calling than females with a longer pupal period and called for a longer period. On the first day of calling, females took more time to initiate calling, on average during the seventh hour of the scotophase, whereas on the second day of calling, most females initiated calling during the fifth hour of the scotophase. On subsequent days of calling, the average time to initiate calling changed to the fourth hour of the scotophase. The mean time of calling per day decreased significantly with the number of days since first calling, and the mean number of calling bouts increased with days since first calling. | The stabilizer, which is used during the preparation of Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs), is of great importance for particle properties. It could be shown that the stabilizer affects the PLGA NPs stability in time and in dependence of temperature, which are important parameters for their practical use. Complex nanoparticles were prepared, for which we have used tetrandrine, azithromycin, and tobramycin that were incorporated into nanoparticles of different origin—PLGA nanoparticles and DPPC/DPPA liposomes. The sizes and surface potentials of complex nanoparticles have been determined. The diameters of the obtained nanoparticles were 150–200 nm, and they had surface potentials with different charge and value (for PLGA with PL 10RS and PLGA with PL 35 are − 32.8 and − 22.5 mV, respectively, and for PLGA with DMAB + 15.0 mV). From calorimetric and spectrophotometric studies, the structural stability of complex nanoparticles with drug has been determined. The dependence on temperature and time could be shown. Structural changes of the particles in the temperature interval of 25–40 °C could be observed. It turned out that these transformations for the complex liposomes prepared with DPPC are completely reversible, and for other nanoparticles, these changes are irreversible, which means, that after phase transition, the nanoparticles internal structure restores in a different ways. Furthermore, a method, which allowed to observe the release of drugs from nanoparticles (as for PLGA, also for liposomal nanoparticles) initiated by temperature, was used. The work makes use of a new and fast technology that can be used to produce complex, drug containing liposomes in a one-step procedure. | eng_Latn | 26,159 |
Diglycolamides (DGA) form reverse-micellar type of supramolecular aggregates upon equilibration with a nitric acid solution that enhances DGA affinity extraordinary towards f-elements. To mimic DGA aggregates, DGA molecules have been preorganized on chemical platforms to form assemblies having a good affinity towards f-elements. However, the synthetic procedures used are quite laborious that limits their large scale applications. To address this problem, a new DGA-bearing monomer N,N-dioctyl,N′-propyl-2-methylacrylamide diglycolamide has been synthesized. This DGA-methacrylate monomer can be polymerized easily, and shows an interesting affinity towards f-element ions both in monomeric and polymeric forms at high nitric acid concentrations. This makes it very promising for the development of fixed-site membranes, resins, and magnetic assemblies for a variety of applications. DGA-methacrylate monomer has been found to assemble on magnetic nanoparticles Fe3O4. DGA-methacrylate coated Fe3O4 particles capture representative trivalent actinide 241Am with a very high efficiency. However, it has been observed that HNO3 induced preorganization of DGA-methacrylate plays an important role in sorption of f-element ions in the polymeric form and self-assembled molecules on the magnetic nanoparticles | The silica layer protected magnetite (Fe3O4) NPs were functionalized with phosphate group bearing monomer ethylene glycol methacrylate phosphate (EGMP) and its polymer (poly(EGMP) having affinity toward f-element ions. The polymerizable double bonds of EGMP anchored on silica coated magnetite NPs were used to grow poly(EGMP) chains by γ-rays induced polymerization. It was observed in the extraction studies that Pu4+ ions sorbed preferentially in Fe3O4@SiO2-EGMP NPs over UO22+ ions from 3 mol L−1 HNO3. Contrary to this, Fe3O4@SiO2-poly(EGMP) NPs did not exhibit significant selectivity toward UO22+ and Pu4+ ions under similar chemical conditions. Indicating a multiple ligating groups coordination requirement for the binding of UO22+ ions with phosphate groups. | Dysfibrinogenemia is characterized by blood coagulation dysfunction induced by an abnormal molecular structure of fibrinogen. Here, we describe a new case. A 32-year-old female was suspected of having dysfibrinogenemia during routine laboratory screening, based on her decreased functional fibrinogen level, normal fibrinogen antigen level, and prolonged thrombin time. We extracted DNA and performed polymerase chain reaction and DNA sequencing to identify genetic mutation. Fibrin polymerization, the kinetics of the fibrinopeptide release, scanning electron microscopy, mass spectrometric analysis, fibrin cross-linking, sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot were conducted. DNA sequencing identified a heterozygous point mutation, Gly13Arg in Aα chain. Fibrin polymerization was markedly impaired (prolonged lag phase and decreased final turbidity). The rate and extent of fibrinopeptide A release from the patient were abnormal and reduced. The mass spectrometry analysis revealed the presence of mutant fibrinogen chains in the patient's circulation. Electron micrographs revealed abnormal fibrin clots. Fibrin cross-linking was normal. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot showed no difference. We report a new case with a mutation in the fibrinopeptide A region, AαGly13Arg. These results indicated that the functional abnormalities were related to delayed and defective fibrinopeptide A cleavage and likely impaired thrombin binding. | eng_Latn | 26,160 |
We have applied rheological methods for the analysis of ethanol-lysozyme interaction during the process of denaturation and aggregation of the protein. At low concentration of ethanol a destruction of the hydration shell of lysozyme is observed. With the increase in the ethanol concentration a structural transformation takes place. It leads to the formation of a protein aggregate with an elongated structure. The rheological characteristics of lysozyme-water–ethanol solution changes from Newtonian to pseudoplastic. | The viscosities, η, of ternary mixtures of water (1) + dimethyl sulfoxide (2) + lysozyme (3) were measured, and the intrinsic viscosities of lysozyme were determined by extrapolating the reduced viscosities to infinitely dilute lysozyme concentration at 298.15 K. A binary mixture of water + dimethyl sulfoxide had a maximum deviation of viscosity at approximately 0.33 mol fraction of dimethyl sulfoxide (x 2 ). Lysozyme unfolded and aggregated with an accompanying increase in the intrinsic viscosity of lysozyme at x 2 = 0.3-0.4. These results indicated that the strong interaction between water and dimethyl sulfoxide might influence the conformation of lysozyme by interfering interactions between water and lysozyme. | The performance of a task is often assumed to be a prerequisite for the learning of many tasks, including the associative conditioning of courtship in the fruit fly, Drosophila melanogaster. Transgenic flies specifically inhibited for the enzyme protein kinase C dissociate the acquisition of learning and memory from performance of the task. They fail to show immediate suppression of courtship but nonetheless develop normal memory of it. | eng_Latn | 26,161 |
Hybrid classical integrable structure of squashed sigma models -- a short summary | Exotic symmetry and monodromy equivalence in Schrodinger sigma models | Improved osmotic energy conversion in heterogeneous membrane boosted by three-dimensional hydrogel interface | eng_Latn | 26,162 |
The epitaxial growth of the mono-functionalized para-quaterphenylene molecule CNHP4 on muscovite mica is investigated. The vacuum deposited molecules aggregate into nanofibers of varying morphology. Due to muscovite’s cm symmetry, almost mutually parallel fibers grow. Polarized light microscopy together with X-ray diffraction resolves the projected orientation of the molecules on the substrate surface and within the fibers. Several different contact planes with the substrate are detected. For all of them, the molecules orient with their long molecule axis approximately perpendicular to the grooved muscovite direction, so that the alignment of the molecules on the substrate is uniform. Kelvin probe force microscopy finds vastly different electrostatic properties of different fiber types and facets. | PART I: The Systematic Crystal Chemistry of Silicates. 1: The Silica Polymorphs. 2: The Feldspars. 3: Micas. 4: Pyroxenes. 5: Amphiboles and Nonclassical Biopyriboles. 6: The Aluminum Silicate Polymorphs. 7: Olivines. 8: Garnets. PART II: Supporting Concepts. 9: Crystal Symmetry. 10: Instrumental Methods. 11: Atomic Bonding Models in Mineralogy. 12: Phase Diagrams. Appendix: Summary of unit-cell data for ambient conditions | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,163 |
An initial approach to the taxonomy of some gram negative yellow pigmented rods. | Arenibacter gen. nov., new genus of the family flavobacteriaceae and description of a new species, Arenibacter latericius sp. nov. | Impact of metallophilicity on "colossal" positive and negative thermal expansion in a series of isostructural dicyanometallate coordination polymers. | eng_Latn | 26,164 |
Systematic effects of crystal-packing forces: biphenyl fragments with hydrogen atoms in all four ortho positions | The X-ray Crystal Structure of the Sulfonated Azo Dye Congo Red, a Non-Peptidic Inhibitor of HIV-1 Protease which also Binds to Reverse Transcriptase and Amyloid Proteins | Oral insulin does not alter gut microbiota composition of NOD mice | eng_Latn | 26,165 |
A Nuclear Magnetic Resonance Study of Poly(L-proline) in Aqueous and Aqueous Salt Solutions | Solvent Mediation of Peptide Conformations: Polyproline Structures in Water, Methanol, Ethanol, and 1-Propanol as Determined by Ion Mobility Spectrometry-Mass Spectrometry | EXO0748−676 Rules out Soft Equations of State for Neutron Star Matter | eng_Latn | 26,166 |
Microcalorimetric study of thermal unfolding of lysozyme in water/glycerol mixtures: An analysis by solvent exchange model | Induction of cholesteric mesophases in nematic liquid crystals, and correlation of absolute configurations of some chiral oxiranes and thiiranes | Adipose Lipolysis Unchanged by Preexercise Carbohydrate Regardless of Glycemic Index | eng_Latn | 26,167 |
A One Hundred Year Perspective of the Reentrant Nematic Phase | Induction of smectic Ad phase in mixtures of polar compounds | On the Defect Structure of Biaxial Nematic Droplets | eng_Latn | 26,168 |
Amphiphilic Molecular Motors for Responsive Aggregation in Water | Photoswitchable molecules in long-wavelength light-responsive drug delivery: from molecular design to applications | Spin-Probe Investigations of Head Group Behavior in Aqueous Dispersions of a Nonionic Amphiphilic Compound | eng_Latn | 26,169 |
Crystallization mechanisms in convective particle assembly. | 1 Convective assembly of a particle monolayer | 1 Convective assembly of a particle monolayer | eng_Latn | 26,170 |
Recombinant cutinase from Fusarium solani pisi was covalently attached to dextran and two derivatized silica supports, Biosil-NH2 and Biosil-Dextran-NH2. Kinetic parameters were determined for all three systems as well as for soluble cutinase. Long-term stability in aqueous media was studied; dextran may have a stabilizing role not only due to the covalent links involved but also in the same way as other polyhydroxides in aqueous media. Differential scanning calorimetry analysis suggests an enhancement of conformational stability of the immobilized forms. | Three unrelated enzymes (ribonuclease, chymotrypsin, and lysozyme) display markedly enhanced thermostability in anhydrous organic solvents compared to that in aqueous solution. At 110-145 degrees C in nonaqueous media all three enzymes inactivate due to heat-induced protein aggregation, as determined by gel filtration chromatography. Using bovine pancreatic ribonuclease A as a model, it has been established that enzymes are much more thermostable in hydrophobic solvents (shown to be essentially inert with respect to their interaction with the protein) than in hydrophilic ones (shown to strip water from the enzyme). The heat-induced aggregates of ribonuclease were characterized as both physically associated and chemically crosslinked protein agglomerates, with the latter being in part due to transamidation and intermolecular disulfide interchange reactions. The thermal denaturation of ribonuclease in neat organic solvents has been examined by means of differential scanning calorimetry. In hydrophobic solvents, the enzyme exhibits greatly enhanced thermal denaturation temperatures (T(m) values as high as 124 degrees C) compared to aqueous solution. The thermostability of ribonuclease towards heat-induced denaturation and aggregation decreases as the water content of the protein powder increases. The experimental data obtained suggest that enzymes are extremely thermostable in anhydrous organic solvents due to their conformational rigidity in the dehydrated state and their resistance to nearly all the covalent reactions causing irreversible thermoinactivation of enzymes in aqueous solution. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,171 |
The effect of temperature on the behaviour of iota-carrageenan (CI) 0.1 wt.%/casein micelles (CM) 0–5 wt.% mixtures has been studied using three techniques: confocal laser scanning microscopy (CLSM), differential scanning calorimetry (DSC) and spectrophotometry. The microscopy clearly shows that those mixed systems separate in two phases, one being enriched in CM. It has been shown that the CM concentration seems to have an effect on the extent of the phase separation phenomenon. The DSC experiments show that addition of CM modifies the helix to coil transition temperature of carrageenan. The enthalpy of melting of helices decreases as the CM concentration increases, and the peak is shifted towards higher temperature. Local electrostatic interactions between carrageenan chains and CM have been studied by a spectrophotometric method using methylene blue (MB) properties of absorption. The absorption spectra of MB in presence of CI and CM were compared with the one of MB in presence of carrageenan alone at temperatures above and below the carrageenan coil to helix transition. The modifications of the spectrum by addition of CM are discussed in terms of interactions and rigidification of the carrageenan chains. | Complex nanomicelles were made from casein and keratin through electrostatic self-assembly and transglutaminase fixation that was proved to be harmless and green. The complex nanomicelles were characterized by dynamic light scattering, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and steady-state florescence. The results show that the complex nanomcelles acquired at the neutral pH in the mass ratio of casein to keratin 4 : 1 exhibit an anomalous sphere shape with uniformsize which the diameter is about 40-70 nm. The complex nanomicelles in solution possess excellent dilution and storage stability due to the fixation and their high ζ-potential (22.8mV). The complex nanomicelles are relatively hydrophilic and have a good potential for industrial application. | The resources of refractory gold ores are abundant, and their effective treatment can bring good economic benefits. This paper investigated the kinetics of leaching gold from refractory gold ores by ultrasonic-assisted electro-chlorination. The effects of ultrasound time ratio, initial hydrochloric acid concentration and leaching temperature on the kinetic parameters were discussed. It is found that the leaching ratio goes up with all the factors increasing. The reaction kinetics is controlled by diffusion. When ultrasound improves the diffusion by reducing the diffusion resistance, the activation energy increases to 37.1 kJ/mol. | eng_Latn | 26,172 |
Novel advanced spray-dried inhalable trehalose microparticulate/nanoparticulate powders with low water content were successfully produced by organic solution advanced spray drying from dilute solution under various spray-drying conditions. Laser diffraction was used to determine the volumetric particle size and size distribution. Particle morphology and surface morphology was imaged and examined by scanning electron microscopy. Hot-stage microscopy was used to visualize the presence/absence of birefringency before and following particle engineering design pharmaceutical processing, as well as phase transition behavior upon heating. Water content in the solid state was quantified by Karl Fisher (KF) coulometric titration. Solid-state phase transitions and degree of molecular order were examined by differential scanning calorimetry (DSC) and powder X-ray diffraction, respectively. Scanning electron microscopy showed a correlation between particle morphology, surface morphology, and spray drying pump rate. All advanced spray-dried microparticulate/nanoparticulate trehalose powders were in the respirable size range and exhibited a unimodal distribution. All spray-dried powders had very low water content, as quantified by KF. The absence of crystallinity in spray-dried particles was reflected in the powder X-ray diffractograms and confirmed by thermal analysis. DSC thermal analysis indicated that the novel advanced spray-dried inhalable trehalose microparticles and nanoparticles exhibited a clear glass transition (Tg). This is consistent with the formation of the amorphous glassy state. Spray-dried amorphous glassy trehalose inhalable microparticles and nanoparticles exhibited vapor-induced (lyotropic) phase transitions with varying levels of relative humidity as measured by gravimetric vapor sorption at 25°C and 37°C. | The purpose of this research was to investigate the influence of changes in the amorphous state on the crystallization of trehalose. Amorphous trehalose is known to stabilize biomaterials; hence, an understanding of crystallization is vital. Amorphous trehalose, prepared by spray-drying, was exposed to either a single step (0-75%) in relative humidity (RH) or to modulated 0-75-0% RH to cause crystallization. For the single-step experiment, two samples crystallized in a predictable manner to form the dihydrate. One sample, while notionally identical, did not crystallize in the same way and showed a mass loss throughout the time at 75% RH, with a final mass less than that expected for the dihydrate. The idiosyncratic sample was seen to have a starting near infrared (NIR) spectra similar to that exhibited by anhydrous crystalline trehalose, implying that short-range order in the amorphous material (or a small amount of crystalline seed, not detectable using powder X-ray diffraction) caused the sample to fail to form the dihydrate fully when exposed to high RH. The modulated RH study showed that the amorphous material interacted strongly with water; the intensity of the NIR traces was not proportional to mass of water but rather the extent of hydrogen bonding. Subsequent crystallization of this sample clearly was a partial formation of the dihydrate, but with the bulk of the sample then shielded such that it was unable to show significant sorption when exposed to elevated RH. It has been shown that the nature of the amorphous form will alter the way in which samples crystallize. With oscillation in RH, it was possible to further understand the interactions between water and amorphous trehalose. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,173 |
BACKGROUND: The aim of the work reported was to develop a procedure using 96-well microtiter plates for the easy determination of protonated groups of compounds including linear poly(amino acid)s and dendritic polymers divided into dendrigraft and dendrimeric structures. This study is a prerequisite step for the quantification of protonated groups in a macromolecule grafted onto a solid surface. RESULTS: The procedure was developed from the modified Bradford protein assay and incorporates several modifications that enable one to determine available amino groups (or even other cationic groups) present on the polyresidues backbone, all withinfiveminutes.BasedontheAthertonmathematicalmodel,weevaluatedthemaximalnumberofCoomassiebluebinding sites on linear, dendrigraft or even dendrimeric structures. CONCLUSION: The mean calculated percentage of occupied sites on a given macromolecule led us to demonstrate that one Coomassie blue molecule interacts with only one single protonated group. Consequently, the developed method using Coomassie blue binding can be used for the quantification of cationic groups in a macromolecule grafted onto a solid surface. c � 2009 Society of Chemical Industry | The efficient immobilization of antibodies on monolithic support is one of the most critical steps when preparing immunoaffinity supports. In this work, the ADECA (amino density estimation by colorimetric assay) method was adapted to tridimensional supports (in a dynamic mode) and proved to be efficient to characterize the antibodies grafting efficiency on 15.3±0.9mg porous glycidyl methacrylate (GMA)-co-ethylene dimethacrylate (EDMA) monolithic columns. The amount of grafted antibodies measured in situ on the monolith by ADECA (8.2±0.2μg of antibodies per milligram of monolith) was consistent with values obtained by bicinchoninic acid assay (BCA) after crushing the monolith. ADECA was shown to be less time-consuming and more versatile than BCA. The ADECA method was further implemented to thoroughly study and optimize the antibody grafting conditions (influence of pH and kinetics of the grafting step) on GMA-based monoliths and to check the covalent nature of the antibody/surface linking and its stability. Using the total amount of grafted antibodies and the amount of recognized antigen, we found that 65±6% of antibodies were able to capture their antigen. Finally, the grafting of Fab and F(ab')(2) fragments demonstrated that no significant improvement of the global binding capacity of the monolith was obtained. | The reduction of proline by Clostridium sporogenes NCIB8053 is coupled to transmembrane proton translocation in an uncoupler-sensitive fashion (and might therefore conserve free energy). This finding serves to explain the increase in the growth yield of this organism when proline is added to a defined growth medium containing glucose as the catabolic substrate. | eng_Latn | 26,174 |
Microbial glycolipids are a class of well-known compounds, but their self-assembly behavior is still not well understood. While the free carboxylic acid end group makes some of them interesting stimuli-responsive compounds, the sugar hydrophilic group and the nature of the fatty acid chain make the understanding of their self-assembly behavior in water not easy and highly unpredictable. Using cryo-transmission electron microscopy (cryo-TEM) and both pH-dependent in situ and ex situ small angle X-ray scattering (SAXS), we demonstrate that the aqueous self-assembly at room temperature (RT) of a family of β-d-glucose microbial glycolipids bearing a saturated and monounsaturated C18 fatty acid chain cannot be explained on the simple basis of the well-known packing parameter. Using the “pH-jump” process, we find that the molecules bearing a monosaturated fatty acid forms vesicles below pH 6.2, as expected, but the derivative with a saturated fatty acid forms infinite bilayer sheets below pH 7.8, instead of ves... | PURPOSE ::: The apparent pKa of the fatty acids within hydrated (30% w/w) model human stratum corneum (SC) lipid mixtures should be measured. ::: ::: ::: METHODS ::: The degree of ionisation of the fatty acids was calculated as a function of pH using Fourier transform infra-red spectroscopy. The relative intensity of the stretching bands of the unionized and ionized carboxylic groups was determined and fitted to the relevant expression for ionic equilibrium of a monoprotic acid. The pKa was then calculated for increasing proportion of unsaturated fatty acid in the lipid mixture. ::: ::: ::: RESULTS ::: Values for pKa in the range 6.2-7.3 were found, increasing with greater proportion of oleic acid. These are some 1.5-3 pH units higher than the pKas of fatty acids in molecular solution. ::: ::: ::: CONCLUSIONS ::: As there exists a pH-gradient across the SC, the degree of ionisation will also vary. In the innermost SC layers, a pH of 7 will produce 90% ionization of the fatty acids and head-group repulsion will be great. At the SC surface, the pH of 5 will cause almost minimal head-group repulsion, tending to increase crystallinity and promote a bilayer structure. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,175 |
The crystal structure of outer surface protein A (OspA) from Borrelia burgdorferi contains a single-layer β-sheet connecting the N- and C-terminal globular domains. The central β-sheet consists largely of polar amino acids and it is solvent-exposed on both faces, which so far appears to be unique among known protein structures. We have accomplished nearly complete backbone H, C and N and C;/Hβ assignments of OspA (28 kDa) using standard triple resonance techniques without perdeuteration. This was made possible by recording spectra at a high temperature (45 °C ). The chemical shift index and 15N T1/T2 ratios show that both the secondary structure and the global conformation of OspA in solution are similar to the crystal structure, suggesting that the unique central β-sheet is fairly rigid. | The hydrophobic effect is the main thermodynamic driving force in the folding of water-soluble proteins1,2. Exclusion of nonpolar moieties from aqueous solvent results in the formation of a hydrophobic core in a protein, which has been generally considered essential for specifying and stabilizing the folded structures of proteins1,2,3,4,5,6. Outer surface protein A (OspA) from Borrelia burgdorferi contains a three-stranded β-sheet segment which connects two globular domains7. Although this single-layer β-sheet segment is exposed to solvent on both faces and thus does not contain a hydrophobic core, the segment has a high conformational stability8. Here we report the engineering of OspA variants that contain larger single-layer β-sheets (comprising five and seven β-strands) by duplicating a β-hairpin unit within the β-sheet. Nuclear magnetic resonance and small-angle X-ray scattering analyses reveal that these extended single-layer β-sheets are formed as designed, and amide hydrogen–deuterium exchange and chemical denaturation show that they are stable. Thus, interactions within the β-hairpin unit and those between adjacent units, which do not involve the formation of a hydrophobic core, are sufficient to specify and stabilize the single-layer β-sheet structure. Our results provide an expanded view of protein folding, misfolding and design. | Since the end of the Cold War, the study of European defence has been dominated by a ‘Common Security and Defence Policy (CSDP)-centric’ approach, while largely neglecting the comparative analysis ... | eng_Latn | 26,176 |
Over recent years, the supposedly universal Hofmeister series has been replaced by a diverse spectrum of direct, partially altered and reversed series. This review aims to provide a detailed understanding of the full spectrum by combining results from molecular dynamics simulations, Poisson–Boltzmann theory and AFM experiments. Primary insight into the origin of the Hofmeister series and its reversal is gained from simulation-derived ion–surface interaction potentials at surfaces containing non-polar, polar and charged functional groups for halide anions and alkali cations. In a second step, the detailed microscopic interactions of ions, water and functional surface groups are incorporated into Poisson–Boltzmann theory. This allows us to quantify ion-specific binding affinities to surface groups of varying polarity and charge, and to provide a connection to the experimentally measured long-ranged electrostatic forces that stabilize colloids, proteins and other particles against precipitation. Based on the stabilizing efficiency, the direct Hofmeister series is obtained for negatively charged hydrophobic surfaces. Hofmeister series reversal is induced by changing the sign of the surface charge from negative to positive, by changing the nature of the functional surface groups from hydrophobic to hydrophilic, by increasing the salt concentration, or by changing the pH. The resulting diverse spectrum reflects that alterations of Hofmeister series are the rule rather than the exception and originate from the variation of ion-surface interactions upon changing surface properties. | Solid-state nanopores have been used extensively in biomolecular studies involving DNA and proteins. However, the interpretation of signals generated by the translocation of proteins or protein-DNA complexes remains challenging. Here, we investigate the behavior of monovalent streptavidin and the complex it forms with short biotinylated DNA over a range of nanopore sizes, salts and voltages. We describe a simple geometric model that is broadly applicable and employ it to explain observed variations in conductance blockage and dwell time with experimental conditions. The general approach developed here underscores the value of nanopore-based protein analysis and represents progress toward the interpretation of complex translocation signals. STATEMENT OF SIGNIFICANCE Nanopore sensing allows investigation of biomolecular structure in aqueous solution, including electric-field-induced changes in protein conformation. This nanopore-based study probes the tetramer-dimer transition of streptavidin, observing the effects of increasing voltage with varying salt type and concentration. Binding of biotinylated DNA to streptavidin boosts the complex’s structural integrity, while complicating signal analysis. We describe a broadly applicable geometric approach that maps stepwise changes in the nanopore signal to real-time conformational transitions. These results represent important progress toward accurate interpretation of nanopore signals generated by macromolecular complexes. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,177 |
To enhance the formation and regeneration ability and the toughness of stereocomplex polylactide (sc-PLA), a high molecular weight stereocomplex branched multi-block polylactide (sb-PCLDA) was synthesized from d-lactide, l-lactide and poly(ε-caprolactone) diol (PCL). High molecular weight sc-PLA has attracted much attention in bioengineering because of its good mechanical and thermal properties, but its brittleness and the poor regeneration ability of the sc crystallites hindered the practical processability, that is, the mixed homochiral and sc crystallites would form in the sc-PLA products after the complete melting and recrystallization processing. The high molecular weight sc-PLA which is easy to form complete stereocomplex and suitable for melt processing needs further research. Herein, sb-PCLDA having PCL, PLLA and PDLA segments on one molecular chain has been synthesized by polymerization of l-lactied and d-lactide with PCL and in situ hydrolysis condensation with silane coupling agents. Differential scanning calorimetry and wide angle X-ray diffraction indicated that sb-PCLDA formed complete sc with high crystallinity and exhibited good sc reformulation ability after multiple melting, suggesting much improved processability. Meanwhile, the sb-PCLDA maintained good thermal properties and hydrolysis resistance. The polymer exhibited significant tensile toughness with an elongation at break of 185%. This facile method could simultaneously improve the mechanical property and recrystallization ability of sc-PLA. | Stereocomplexation between poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) provides a feasible route for improving the performance of polylactide (PLA), including mechanical strength, thermal stability and hydrolysis resistance. In recent years, several effective methods have been developed to prepare polylactide stereocomplexes (sc-PLA) from commercially available, linear, high-molecular-weight PLLA and PDLA. However, it is still a big challenge to attain pure sc-PLA in the melt-processed products because the prepared sc-PLA has a very poor melt stability, that is the ability to trigger the reformulation of stereocomplex (sc) crystallites after complete melting is significantly depressed, resulting in the formation of mixed homochiral (hc) and sc crystallites. Here we present a facile strategy to fabricate sc-PLA with good melt stability by low-temperature (180 °C) melt-blending of equimolar PLLA and PDLA in the presence of a trace amount (0.1–0.5 wt%) of a cross-linker. During the blending process, sc crystallites form rapidly, followed by a slight cross-linking of PLLA and PDLA chain couples in the mobile amorphous phase, whereas the chain couples in the crystalline phase hardly participate in the cross-linking reaction. The exclusive cross-linking of PLA chains in the amorphous phase not only allows for the introduction of abundant cross-linking points at the ends of the chain couples to prevent them from completely decoupling upon melting but also retains large amounts of long crystallizable PLA segments existing in the initially formed sc crystallites to impart the resulting sc-PLA with an excellent recrystallization ability upon cooling. The formation or reformulation of sc crystallites in the continuous melting and recrystallization process is found to be perfectly reversible, without any trace of hc crystallites. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,178 |
The influenza A M2 protein is a 97-residue integral membrane protein involved in viral budding and proton conductance. Although crystal and NMR structures exist of truncated constructs of the protein, there is disagreement between models and only limited structural data are available for the full-length protein. Here, the structure of the C-terminal juxtamembrane region (sites 50–60) is investigated in the full-length M2 protein using site-directed spin-labeling electron paramagnetic resonance (EPR) spectroscopy in lipid bilayers. Sites 50–60 were chosen for study because this region has been shown to be critical to the role the M2 protein plays in viral budding. Continuous wave EPR spectra and power saturation data in the presence of paramagnetic membrane soluble oxygen are consistent with a membrane surface associated amphipathic helix. Comparison between data from the C-terminal juxtamembrane region in full-length M2 protein with data from a truncated M2 construct demonstrates that the line shapes and oxygen accessibilities are remarkably similar between the full-length and truncated form of the protein. | Amphipathic helices in membrane proteins that interact with the hydrophobic/hydrophilic interface of the lipid bilayer have been difficult to structurally characterize. Here, the backbone structure and orientation of an amphipathic helix in the full-length M2 protein from influenza A virus has been characterized. The protein has been studied in hydrated DMPC/DMPG lipid bilayers above the gel to liquid-crystalline phase transition temperature by solid-state NMR spectroscopy. Characteristic PISA (Polar Index Slant Angle) wheels reflecting helical wheels have been observed in uniformly aligned bilayer preparations of both uniformly 15N labeled and amino acid specific labeled M2 samples. Hydrogen/deuterium exchange studies have shown the very slow exchange of some residues in the amphipathic helix and more rapid exchange for the transmembrane helix. These latter results clearly suggest the presence of an aqueous pore. A variation in exchange rate about the transmembrane helical axis provides additional support for this claim and suggests that motions occur about the helical axes in this tetramer to expose the entire backbone to the pore. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,179 |
The opportunistic pathogen Burkholderia cenocepacia contains three soluble carbohydrate-binding proteins, related to the fucose-binding lectin PA-IIL from Pseudomonas aeruginosa. All contain a PA-IIL-like domain and two of them have an additional N-terminal domain that displays no sequence similarities with known proteins. Printed arrays screening performed on the shortest one, B. cenocepacia lectin A (BC2L-A), demonstrated the strict specificity for oligomannose-type N-glycan structures (Lameignere E, Malinovská L, Sláviková M, Duchaud E, Mitchell EP, Varrot A, Sedo O, Imberty A, Wimmerová M. 2008. Structural basis for mannose recognition by a lectin from opportunistic bacteria Burkholderia cenocepacia. Biochem J. 411:307-318.). The disaccharides alphaMan1-2Man, alphaMan1-3Man, and alphaMan1-6Man and the trisaccharide alphaMan1-3(alphaMan1-6)Man were tested by titration microcalorimetry in order to evaluate their affinity for BC2L-A in solution and to characterize the thermodynamics of the binding. Oligomannose analogs presenting two mannoside residues separated by either flexible or rigid spacer were also tested. Only the rigid one yields to high affinity binding with a fast kinetics of clustering, while the flexible analog and the trimannoside display moderate affinities and no clustering effect on short time scale. The crystal structures of BC2L-A have been obtained in complex with alphaMan1-3Man disaccharide and alphaMan1(alphaMan1-6)-3Man trisaccharide. The lengthy time required for the co-crystallization with the trisaccharide allowed for the formation of cluster since in the BC2L-A-trimannose complex solved at 1.1 A resolution, the sugar creates a bridge between two adjacent dimers, yielding to molecular strings. AFM experiments were performed in order to visualize the filaments formed in solution by this type of interaction. | The lectin from Pseudomonas aeruginosa (PA-IIL) is involved in host recognition and biofilm formation. Lectin not only displays an unusually high affinity for fucose but also binds to L-fucose, L-galactose and D-arabinose that differ only by the group at position 5 of the sugar ring. Isothermal calorimetry experiments provided precise determination of affinity for the three methyl-glycosides and revealed a large enthalpy contribution. The crystal structures of the complexes of PA-IIL with L-galactose and Met-beta-D-arabinoside have been determined and compared with the PA-IIL/fucose complex described previously. A combination of the structures and thermodynamics provided clues for the role of the hydrophobic group in affinity. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 26,180 |
The effect of cavity structure (semivertical angle) on nucleation behaviour has been investigated both theoretically and experimentally. A relationship between work required to form a nucleus in a cavity and the structure of the cavity has been derived theoretically based on classical rate theory and has been verified experimentally on artificially prepared cavities with a water-CO2 system. The activation energy required for homogeneous nucleation (within the bulk liquid phase), heterogeneous nucleation (on a plane surface) and cavitational nucleation have been compared and a universal relationship for nucleation (homogeneous, heterogeneous and cavitational) has been established. The experimental data were acquired based on statistical fluctuation theory. | Vascular plants transport water under negative pressure without constantly creating gas bubbles that would disable their hydraulic systems. Attempts to replicate this feat in artificial systems almost invariably result in bubble formation, except under highly controlled conditions with pure water and only hydrophilic surfaces present. In theory, conditions in the xylem should favor bubble nucleation even more: there are millions of conduits with at least some hydrophobic surfaces, and xylem sap is saturated or sometimes supersaturated with atmospheric gas and may contain surface-active molecules that can lower surface tension. So how do plants transport water under negative pressure? Here, we show that angiosperm xylem contains abundant hydrophobic surfaces as well as insoluble lipid surfactants, including phospholipids, and proteins, a composition similar to pulmonary surfactants. Lipid surfactants were found in xylem sap and as nanoparticles under transmission electron microscopy in pores of intervessel pit membranes and deposited on vessel wall surfaces. Nanoparticles observed in xylem sap via nanoparticle-tracking analysis included surfactant-coated nanobubbles when examined by freeze-fracture electron microscopy. Based on their fracture behavior, this technique is able to distinguish between dense-core particles, liquid-filled, bilayer-coated vesicles/liposomes, and gas-filled bubbles. Xylem surfactants showed strong surface activity that reduces surface tension to low values when concentrated as they are in pit membrane pores. We hypothesize that xylem surfactants support water transport under negative pressure as explained by the cohesion-tension theory by coating hydrophobic surfaces and nanobubbles, thereby keeping the latter below the critical size at which bubbles would expand to form embolisms. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,181 |
This is a study of 10 asymmetric gemini surfactants that self-assemble into vesicles which, in turn, self-assemble into gels. The geminis have the following general structure: long-chain/phosphate/2-carbon spacer/quaternary nitrogen/short-chain. Dynamic light scattering and transmission electron microscopy (TEM) demonstrate that in dilute aqueous systems these compounds self-assemble into vesicles. The vesicles are cohesive as proven by cryo-high resolution electron microscopy (cryo-HRSEM) images that reveal a pearls on a string morphology. These strings of vesicles create a complex network that rigidifies the water. The one gemini in the study that does not form a gel is also the only vesicle system that, according to cryo-HRSEM and TEM, assembles into clumps rather than chains. It is proposed that the vesicles are cohesive owing to protrusion of short chains from the vesicle surfaces, thereby creating hydrophobic patches whose intervesicular overlap supersedes the normal membrane/membrane repulsive forces. Analogous geminis having two long chains, neither of which are thought capable of departing from their bilayers, also form vesicles, but they are noncohesive (as expected from the model). Rheological experiments carried out on the gels show that gelation is mechanically reversible. Thus, if an applied torque breaks a string, the string can rapidly mend itself as long as the temperature exceeds its calorimetrically determined T m value. Gel strength, as manifested by the yield stress of the soft material, was shown to be particularly sensitive to the structure of the gemini. All three individual components of the systems (geminis, vesicles, and gels) have widespread practical applications. | The self-assembly of lecithin-bile salt mixtures in solutions has long been an important research topic, not only because they are both biosurfactants closely relevant to physiological functions but also for the potential biomedical applications. In this paper, we report an unusual biological hydrogel formed by mixing bile salts and lecithin at low bile salt/lecithin molar ratios (B0) in water. The gel can be prepared at a total lipid concentration as low as ∼15 wt %, and the solidlike property of the solutions was confirmed by dynamic rheological measurements. We used cryo-TEM and SAXS/SANS techniques to probe the self-assembled structure and clearly evidence that the gel is made up of jammed swollen multilamellar vesicles (liposomes), instead of typical fibrous networks found in conventional gels. A mechanism-based on the strong repulsion between bilayers due to the incorporation of negatively charged bile salts is proposed to explain the swelling of the liposomes. In addition to gel, a series of phases, including viscoelastic, gel-like, and low-viscosity fluids, can be created by increasing B0. Such a variety of phase behaviors are caused by the transformation of bilayers into cylindrical and spheroidal micelles upon the change of the effective molecular geometry with B0. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,182 |
The fracture toughness of mollusk shell nacre has been attributed to many factors, one of which is the intracrystalline incorporation of nacre-specific proteins. Although mechanical force measurements have been made on the nacre layer and on individual calcium carbonate crystals containing occluded organic molecules and macromolecules, there are few if any studies which examine the impact of occluded proteins on the mechanical properties of calcium carbonate crystals. To remedy this, we performed microcompression studies of calcite crystals grown in the presence and absence of two recombinant nacre proteins, r-AP7 (H. rufescens, intracrystalline proteome) and r-n16.3 (P. fucata, framework proteome), both of which are known aggregators that form hydrogel nanoinclusions within in vitro calcite. We find that, relative to protein-free calcite, the intracrystalline inclusion of either r-AP7 or r-n16.3 nacre protein hydrogels within the calcite crystals leads to a reduction in strength. However, nacre protein-modified crystals were found to exhibit elastic deformation under force compared to control scenarios, with no discernable differences noted between intracrystalline or framework protein-modified crystals. We conclude from our in vitro microcompression studies that the intracrystalline incorporation of nacre proteins can contribute to fracture-resistance of the crystalline phase by significantly reducing both modulus AND critical strength. | Biogenic single-crystal composites, such as sea urchin spines and calcitic prisms from mollusk shells, contain organic macromolecules inside of inorganic single-crystal matrices. The nanoscale internal structure of these materials, however, is poorly understood, especially how the biomacromolecules are distributed within the crystals without signifi cantly disrupting the crystalline lattice. Here, annular dark-fi eld scanning transmission electron microscopy and electron tomography reveal, in three dimensions, how biomacromolecules are distributed within the calcitic prisms from Atrina rigida shells. Disk-like nanopatches, whose scattering intensity is consistent with organic inclusions, are observed to be anisotropically arranged within a continuous, single-crystalline calcite matrix. These nanopatches are preferentially aligned with the (000 l ) planes of calcite. Along the crystallographic caxis, there are alternating organic-rich and -poor regions on a length scale of tens of nanometers, while, in the ab plane, the distribution of nanopatches is more random and uniform. The structural features elucidated in this work have relevance to understanding the structure–property relationships and formation mechanisms of biominerals, as well as to the development of bioinspired strategies to extrinsically tune the properties of single-crystals. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 26,183 |
Extending the life-cycle of reverse osmosis membranes: A review | Biofilm formation, cleaning, re-formation on polyamide composite membranes | Remodeling of chromatin loops does not account for specification of replication origins during Xenopus development | eng_Latn | 26,184 |
Energetics of the dipole flip-flop motion in a ferroelectric polymer chain. | First-Principles Study of the α–β Phase Transition of Ferroelectric Poly(vinylidene difluoride): Observation of Multiple Transition Pathways | High-affinity glucose uptake in Saccharomyces cerevisiae is not dependent on the presence of glucose-phosphorylating enzymes | eng_Latn | 26,185 |
Additional peaks in the cluster size distribution of amphiphile + water systems: a clue for shape/phase transition or statistical uncertainty | On the Difference between Self-Assembling Process of Monomeric and Dimeric Surfactants with the Same Head to Tail Ratio: A Lattice Monte Carlo Simulation | An instrumental variable approach finds no associated harm or benefit from early dialysis initiation in the United States | eng_Latn | 26,186 |
Annihilation of Edge Dislocations in SmA Liquid Crystals | Soft Matter Physics: An Introduction | Synthesis of Microcapsule by Staphylococcus aureus Is Not Responsive to Environmental Phosphate Concentrations | eng_Latn | 26,187 |
A density functional model, based on the coarse grained density distribution is used to analyse the melting of hard spheres and discs. The role of the attractive interaction is modelled in a mean field approximation, to get the full solid-liquid-vapour phase diagram of a system with Lennard-Jones interactions. | The phase behaviour of hard spherocylinders is calculated using the classical density functional theory of freezing. In particular, we construct a modified weighted-density approximation and calculate the bulk phase diagram. While the stability regime of the isotropic, nematic and smectic-A phases is in reasonable agreement with computer simulation data, the theory fails to describe the correct stability of the crystalline phases. Furthermore, we investigate the phase behaviour in an external field coupling to the orientational degrees of freedom. As a result, bulk phases which have the same translational symmetry but a different orientational symmetry can be transformed continuously into each other above a critical strength of the external field. | The principal impediment to gene therapy is the development of efficient, nontoxic gene carriers that can handle and deliver foreign genetic materials into various cell types, including healthy and... | eng_Latn | 26,188 |
Positively charged dendronized polymers with protonated amine groups at the periphery and different dendron generations are cylindrically shaped nanoobjects whose radii and linear charge densities can be varied systematically. These polyelectrolytes have been complexed with DNA and subsequently adsorbed on precoated mica substrates. The analysis of scanning force microscopy data indicates that DNA wraps around the dendronized polymers. The calculated pitch is 2.30 ± 0.27 and 2.16 ± 0.27 nm for DNA wrapped around dendronized polymers of generation two and four, respectively. The complex with the second generation has been shown to be negatively charged, which is consistent with the theory of spontaneous overcharging of macro-ion complexes, when the electrostatic contribution to the free energy dominates over the elastic energy. The complexes may be of interest for the development of nonviral gene delivery systems. | DNA condensation and charge inversion usually occur in solutions of multivalent counterions. In the present study, we show that the organic monovalent ions of tetraphenyl chloride arsenic (Ph4As+) can induce DNA compaction and even invert its electrophoretic mobility by single molecular methods. The morphology of condensed DNA was directly observed by atomic force microscopy (AFM) in the presence of a low concentration of Ph4As+ in DNA solution. The magnetic tweezers (MT) measurements showed that DNA compaction happens at very low Ph4As+ concentration (≤1 μM), and the typical step-like structures could be found in the extension-time curves of tethering DNA. However, when the concentration of Ph4As+ increased to 1 mM, the steps disappeared in the pulling curves and globular structures could be found in the corresponding AFM images. Electrophoretic mobility measurement showed that charge inversion of DNA induced by the monovalent ions happened at 1.6 mM Ph4As+, which is consistent with the prediction based on the strong hydrophobicity of Ph4As+. We infer that the hydrophobic effect is the main driving force of DNA charge inversion and compaction by the organic monovalent ion. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 26,189 |
Human health has been challenged by multi-drug-resistant microorganisms for several decades. Herein, we have developed a main-chain imidazolium oligomer (IBN-1) material to combat broad spectrum of pathogenic strains, including drug-resistant Klebsiella pneumoniae, Vancomycin-resistant enterococcus, Methicillin-resistant Staphylococcus aureus and fluconazole-resistant yeast Cryptococcus neoformans, while displaying minimal hemolysis (HC(50)/MIC values over 3000) and a very high therapeutic index of 37 for killing S. aureus under inflammatory conditions in vivo. | Infectious diseases and the increasing threat of worldwide pandemics have underscored the importance of antibiotics and hygiene. Intensive efforts have been devoted to developing new antibiotics to meet the rapidly growing demand. In particular, advancing the knowledge of the structure–property–activity relationship is critical to expedite the design and development of novel antimicrobial with the needed potential and efficacy. Herein, a series of new antimicrobial imidazolium oligomers are developed with the rational manipulation of terminal group's hydrophobicity. These materials exhibit superior activity, excellent selectivity, ultrafast killing (>99.7% killing within 30 s), and desirable self-gelling properties. Molecular dynamic simulations reveal the delicate effect of structural changes on the translocation motion across the microbial cell membrane. The energy barrier of the translocation process analyzed by free energy calculations provides clear kinetic information to suggest that the spontaneous penetration requires a very short timescale of seconds to minutes for the new imidazolium oligomers. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 26,190 |
The ability of polysaccharides to enhance viscosity and to form gels has led to their widespread use in food products. Often synergistic combinations of polysaccharides are employed in order to manipulate rheological characteristics and, in addition, to provide effective savings in production costs. Common examples of polysaccharide blends used include kappa-carrageenan-galactomannan, xanthan-galactomannan and alginate-pectin. The origin of the synergy in these polysaccharide mixtures has been the subject of extensive research studies over the last twenty years or so and still gives rise to considerable controversy 1,2. Cairns et al 3 have identified four different types of gel structure that might arise in binary mixtures of polysaccharides and these are illustrated in figure 1. In structure a) only one of the polysaccharides contributes to the gel network and the second polymer is simply entrapped within the matrix. In structure b) both polysaccharides form independent penetrating networks. Structure c) arises if polymer demixing occurs prior to gelation giving a phase separated network and structure d) is termed a coupled network and arises when sections of the two polysaccharides associate. | The rheological behavior of mixtures of xanthan with different galactomannans is examined to evaluate the influence of the structure of galactomannan and that of the mixture composition on the physical properties; the larger synergy is observed for locust bean gum in the presence of xanthan. It is also shown that pH has only a slight influence on the rheology down to pH = 3.59; at lower pH, the G′ modulus decreases significantly. Then, the behavior of xanthan–methylcellulose mixtures is studied, paying particular attention to the storage modulus (G′) of the system, often equated to “gel strength”. The modulus values for direct dissolution of the two polysaccharides in 0.1 M NaCl show that xanthan and methylcellulose are incompatible. The rheological behavior observed is in agreement with DSC results which indicate that no specific interaction between the two polymers exists. However, upon increasing temperature, the modulus of methylcellulose increases substantially between 65 and 70 °C because of physical gelation and dominates the rheology of the mixtures. When temperature is decreased to 37 °C, the clear methylcellulose gel formed remains stable, still giving the main contribution to the overall rheology of the system. Finally, ternary systems are studied when xanthan is mixed with galactomannan and methylcellulose. In this case H-bonds involved in galactomannan–xanthan interaction break when temperature increases causing a decrease in rheological moduli which is then compensated by the gelation of methylcellulose giving an original large increase in moduli for the ternary systems. This can be interpreted as the presence of two independent but interpenetrating networks. The role of pH for these ternary systems is interesting: it is still dominated by methylcellulose and nearly independent of acidic pH (down to pH = 1.8). | Life as we know it requires three basic types of polymers: polypeptide, polynucleotide, and polysaccharide. Here we evaluate both universal and idiosyncratic characteristics of these biopolymers. We incorporate this information into a model that explains much about their origins, selection, and early evolution. We observe that all three biopolymer types are pre-organized, conditionally self-complementary, chemically unstable in aqueous media yet persistent because of kinetic trapping, with chiral monomers and directional chains. All three biopolymers are synthesized by dehydration reactions that are catalyzed by molecular motors driven by hydrolysis of phosphorylated nucleosides. All three biopolymers can access specific states that protect against hydrolysis. These protected states are folded, using self-complementary interactions among recurrent folding elements within a given biopolymer, or assembled, in associations between the same or different biopolymer types. Self-association in a hydrolytic environment achieves self-preservation. Heterogeneous association achieves partner-preservation. These universal properties support a model in which life’s polymers emerged simultaneously and co-evolved in a common hydrolytic milieu where molecular persistence depended on folding and assembly. We believe that an understanding of the structure, function, and origins of any given type of biopolymer requires the context of other biopolymers. | eng_Latn | 26,191 |
Amorphous calcium carbonate (ACC) has been of keen interest in the biomimetics field because of recent evidence which suggests it plays an important role in biomineralization. In this report, an in vitro model system is used to examine the composition of an amorphous phase generated by polyanionic process-directing agents, such as the sodium salt of polyaspartic acid (Pasp), which is considered a simple mimic to the proteins associated with calcific biominerals. This additive leads to the formation of a highly hydrated, amorphous mineral precursor to calcium carbonate (CaCO 3 ), referred to as a polymer-induced liquid-precursor (PILP) phase. The precursor phase was collected by centrifugation, and the quantity of precursor phase and the water content were determined. It was found that Pasp promotes and stabilizes the amorphous precursor, which has a composition that steadily changes with time as the polymer and water are excluded. Elemental analysis was used to investigate the role of the polymer in influencing the calcium/carbonate ratio, the water content, and the amount of precursor phase. Raman and ATR–FTIR spectroscopy were used to compare the compositions of the precursor phases generated with different polymeric concentrations. The role of Pasp in generating and stabilizing the ACC precursor phase is discussed. | Nanostructured organic crystals have a broad application potential as pharmaceuticals, pigments, or catalysts. The development of facile and reproducible synthetic routes and the upscaling of the process, however, still remain a challenge. Here, we describe the synthesis of macroporous hierarchically structured microspheres with nanoplatelets as building blocks of a model organic molecule—dl-glutamic acid (dl-Glu)—via a polymer-induced liquid precursor (PILP) phase using oppositely charged polyethylene imine (PEI) as a polymeric additive. The impacts of experimental parameters such as [dl-Glu], temperature, solvent composition, and the pH value were systematically investigated for the dl-Glu morphosynthesis process. A mechanism is suggested to explain the precipitation of dl-Glu with PEI as an additive based on a multistep process: (1) the formation, growth, and coalescence of the PILP droplets; (2) the homogeneous nucleation of nanoplatelets within PILP droplets and (3) the reorientation of nanoplatelets... | Background ::: Serum calcium (Ca) and inorganic phosphate (Pi) concentrations and calcium-phosphate product (CPP) levels are positively associated with worse outcomes in patients with chronic kidney disease, but there are few data for Pi or Ca and none for CPP in patients with chronic heart failure (CHF). | eng_Latn | 26,192 |
The objective of this work is to understand the charging dynamics of metal nanoparticles under wavelength-selected UV irradiation, with a particular focus on the effect of particle structure on the quantum yield. We employed an ion mobility analysis technique to measure the size-resolved single charging efficiency of structure-controlled silver nanoparticles (spheres vs. aggregates) in the mobility diameter (D m) range of 10 ∼ 100 nm. We found that the measured particle charging efficiency follows D 2 m dependence for both spherical and aggregate particles. Based on the measured charging efficiency and calculated particle photon absorption cross section, we are also able to determine the mobility size dependence of photoelectric quantum yield for both spheres and aggregates. The quantum yield of spheres is a constant for larger particles (50 nm or larger) but significantly enhanced as particle size decreases. The quantum yield of aggregates is shown to be particle structure dependent and does not behave a... | An experimental study has been carried out to determine the aerosol charge distribution through photocharging process. Particle charge distribution was studied in dependency on particle number concentration and irradiation intensity. While highly positively charged aerosols were obtained for particle number concentrations below 5×10 11 m −3 , approximately symmetrical bipolar charge distributions were measured for number concentrations of about 2×10 13 m −3 . The theoretical description was made on basis of the previously developed model, which was extended by a term accounting for ion diffusion losses. Theoretical results reflected experimental observations. The necessity of taking into account diffusion discharging of particles by gas ions is determined by a dimensionless factor depending on initial parameters. Since the charge distribution through photocharging becomes a known function of particle and irradiation parameters, a photocharger may be used instead of a neutralizer to produce a defined charge distribution. | Like any typical food system, bone soup (or broth), a traditional nourishing food in many cultures, contains a colloid dispersion of self-assembled micro/nano-particles. Food ingestion results in the direct contact of food colloidal MNPs with immune cells. Will they ever interact with each other? To answer the question, MNPs and NPs were separated from porcine bone soup and labeled with Nile Red, and their uptake by murine oral macrophages and its consequent effects were investigated. Colloidal particle samples of UF-MNPs and SEC-NP were prepared from porcine bone soup by ultrafiltration (UF) and size-exclusion chromatography, respectively. Their mean hydrodynamic diameters were 248 ± 10 nm and 170 ± 1 nm with dominant composition of protein and lipid. Particles in both samples were found to be internalized by oral macrophages upon co-incubation at particle/cell ratios of 14,000/1. In normal oral macrophages, the particle uptake exerted influence neither on the cellular cytosolic membrane potential (Vmem) nor mitochondrial superoxide level, as were indicated with fluorescent dyes of DiBAC4(3) and MitoSOX Red, respectively. However, when oral macrophages were challenged by peroxyl radical inducer AAPH, the engulfment of UF-MNPs and SEC-NPs mitigated the peroxyl radical induced membrane hyperpolarization effect by up to 70%, and the suppression on the oxygen respiration in mitochondria by up to 100%. Those results provide evidence of the direct interaction between food colloidal particles with immune cells, implying a possible new mode of food-body interaction. The uptake of food colloidal particles by oral macrophages can mitigate the peroxyl radical induced membrane hyperpolarization effect and suppress the oxygen respiration in mitochondria. Jianwu Zhou and coworkers from Zhejiang Gongshang University, China, separated micro/nano particles of 248 ± 10 nm and 170 ± 1 nm in diameter from porcine bone soup via membrane ultrafiltration and gel-filtration, respectively. By labeling the colloidal particles with hydrophobic fluorescent dyes, they tracked their internalization by oral macrophages upon co-incubation. It was found the food colloidal particles ingestion had no influence on the cell plasma membrane potential and mitochondrial superoxide level of the normal oral macrophages. However, when macrophages were irritated by peroxyl radical inducer 2,2′-azobis (2-amidinopropane) dihydrochloride, the food micro/nano particles exhibited a pacifying effect. This finding reveal a possible new mode of food-body interaction. | eng_Latn | 26,193 |
Space Cellular Robotic System is a novel manipulating device which can replace space manipulator to realize on-orbit assembly, inspection, and maintenance of large space facilities. In this paper, the expressions system of Space Cellular Robotic System is defined, and the mathematical expressions of robot actions and configurations are established. Then an algorithm based on the minimum set covering problem is proposed to solve the configuration planning problem. Simulation and analysis show that the algorithm can realize the configuration planning with known configurations, and can give the reference of functions and parameters when new configuration design is needed. | Consisting of a collection of modules with the same connection interfaces, a reconfigurable modular robot can be assembled into different configurations to meet different task requirements. The configuration optimization of modular robot is formulated as an optimal design process that is selecting sets of modules and assembling them together to get optimal configurations. To solve the problem of configuration design, this paper presents a multi-objective optimization method for assembly-level modular robots which can bring us more convince to present the modular robots. An automatic generation method of the configuration from an assembly model is presented. With the assembly as the design variable, a multi-objective optimization model of configuration optimization is founded to search for the optimal solutions. Based on our modular robot system, an example is provided to verify the effectiveness of this approach. | The lamellar configuration of the red cell membrane includes a (liquid) superficial bilayer of amphiphilic molecules supported by a (rigid) subsurface protein meshwork. Because of this composite structure, the red cell membrane exhibits very large resistance to changes in surface density or area with very low resistance to in-plane extension and bending deformations. The primary extrinsic factor in cell deformability is the surface area-to-volume ratio which establishes the minimum-caliber vessel into which a cell can deform (without rupture). Within the restriction provided by surface area and volume, the intrinsic properties of the membrane and cytoplasm determine the deformability characteristics of the red cell. Since the cytoplasm is liquid, the static rigidity of the cell is determined by membrane elastic constants. These include an elastic modulus for area compressibility in the range of 300-600 dyn/cm, an elastic modulus for in-plane extension or shear (at constant area) of 5-7 X 10(-3) dyn/cm, and a curvature or bending elastic modulus on the order of 10(-12) dyn.cm. Even though small, the surface rigidity of the cell membrane is sufficient to return the membrane capsule to a discoid shape after deformation by external forces. Viscous dissipation in the peripheral protein structure (cytoskeleton) dominates the dynamic response of the cell to extensional forces. Based on a time constant for recovery after extensional deformation on the order of 0.1 sec, the coefficient of surface viscosity is on the order of 10(-3) dyn.sec/cm. On the other hand, the dynamic resistance to folding of the cell appears to be limited by viscous dissipation in the cytoplasmic and external fluid phases. Dynamic rigidities for both extensional and folding deformations are important factors in the distribution of flow in the small microvessels. Although the red cell membrane normally behaves as a resilient viscoelastic shell, which recovers its conformation after deformation, structural relaxation and failure lead to break-up and fragmentation of the red cell. The levels of membrane extensional force which is two orders of magnitude less than the level of tension necessary to lyse vesicles by rapid area dilation. Each of the material properties ascribed to the red cell membrane plays an important role in the deformability and survivability of the red cell in the circulation over its several-month life span. | eng_Latn | 26,194 |
Experiments on core centering in immiscible compound drops were conducted on the second United States Microgravity Laboratory Space Shuttle Mission (USML-2). It was observed that the inner and outer interfaces of a compound drop became concentric during capillary oscillations. These oscillations either were the freely decaying type, which occurred following the deployment of the drops, or were externally forced on the drop by modulating the positioning acoustic fields in the Drop Physics Module (DPM) experimental chamber. The results on core centering in liquid–liquid drops should stimulate theoretical studies in this field. | Polymer shells with high sphericity and uniform wall thickness are always needed in the inertial confined fusion (ICF) experiments. Driven by the need to control the shape of water-in-oil (W1/O) compound droplets, the effects of the density matching level, the interfacial tension and the rotation speed of the continuing fluid field on the sphericity and wall thickness uniformity of the resulting polymer shells were investigated and the spherical and concentric mechanisms were also discussed. The centering of W1/O compound droplets, the location and movement of W1/O compound droplets in the external phase (W2) were significantly affected by the density matching level of the key stage and the rotation speed of the continuing fluid field. Therefore, by optimizing the density matching level and rotation speed, the batch yield of polystyrene (PS) shells with high sphericity and uniform wall thickness increased. Moreover, the sphericity also increased by raising the oil/water (O/W2) interfacial tension, which drove a droplet to be spherical. The experimental results show that the spherical driving force is from the interfacial tension affected by the two relative phases, while the concentric driving force, as a resultant force, is not only affected by the three phases, but also by the continuing fluid field. The understanding of spherical and concentric mechanism can provide some guidance for preparing polymer shells with high sphericity and uniform wall thickness.Polymer shells with high sphericity and uniform wall thickness are always needed in the inertial confined fusion (ICF) experiments. Driven by the need to control the shape of water-in-oil (W1/O) compound droplets, the effects of the density matching level, the interfacial tension and the rotation speed of the continuing fluid field on the sphericity and wall thickness uniformity of the resulting polymer shells were investigated and the spherical and concentric mechanisms were also discussed. The centering of W1/O compound droplets, the location and movement of W1/O compound droplets in the external phase (W2) were significantly affected by the density matching level of the key stage and the rotation speed of the continuing fluid field. Therefore, by optimizing the density matching level and rotation speed, the batch yield of polystyrene (PS) shells with high sphericity and uniform wall thickness increased. Moreover, the sphericity also increased by raising the oil/water (O/W2) interfacial tension, which d... | Plasmids classified to the IncP-1 incompatibility group belong to the most stably maintained mobile elements among low copy number plasmids known to date. The remarkable persistence is achieved by various tightly controlled stability mechanisms like active partitioning, efficient conjugative transfer system, killing of plasmid-free segregants and multimer resolution. The unique feature of IncP-1 plasmids is the central control operon coding for global regulators which control the expression of genes involved in vegetative replication, stable maintenance and conjugative transfer. The multivalent regulatory network provides means for coordinated expression of all plasmid functions. The current state of knowledge about two fully sequenced plasmids RK2 and R751, representatives of the IncP-1 and IncP-1 subgroups, is presented. | eng_Latn | 26,195 |
Diffusion in pure gels and gels with immobilized cells was analyzed. A model of diffusion assuming a homogeneous cell distribution in gel was improved by introducing a tortuosity value. By theoretical analysis and numerical modeling it was shown that the tortuosity of a gel with immobilized cells is the product of two factors: (1) tortuosity generated by the cells, Tc, and (2) tortuosity of the gel matrix, Tg, both variables being a function of cell volume fraction, c. Total tortuosity is thus T“ ) TcTg. On the basis of this approach, it was possible to analyze diffusivity data for gels with immobilized cells. It was shown that, in these systems, the diffusivity ) De/D0 is a complex function of (1) diffusivity in the gel, g, and (2) diffusivity in immobilized cells, c. The developed model allowed for the description of the dependence of De/D0 on c. Comparison with numerous published experimental data showed a good fit. Observed deviations might be explained by nonhomogeneous cell distributions inside the gel matrix. | The diffusivities of glucose and ethanol in cell-free and cell-occupied membranes of calcium alginate were measured in a diffusion cell. The lag time analysis was used. Diffusivities decreased with increasing alginate concentration and were comparable with those in water for a 2% alginate membrane. Glucose and ethanol concentrations had no effect on the respective diffusion coefficients. The ratio of ethanol diffusivity to glucose diffusivity in 2 and 4% alginate agreed closely with the inverse ratio of the hydrodynamic raii for the two molecules in water, indicating that the hydrodynamic theory of diffusion in liquids may be applicable to diffusion in dilute alginate gels. Also, the presence of 20% dead yeast cells had no effect on the diffusivities. The data reported can be used to study reaction and diffusion in immobilized cell reactors and cell physiology under immobilized conditions. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,196 |
The shape separations of suspended gold nanoparticles were investigated using size-exclusion chromatography. The separations in shapes were identified by examining the 3-D chromatograms obtained by employing a diode-array detection system and were further confirmed by analyzing TEM images of fractional collection of particles. This shape separation was achieved by adding a mixed-surfactant system containing sodium dodecyl sulfate and poluoxyethylene (23) dodecanol (Brij-35) into the eluent, which apparently affects the adsorption behaviors of both rodlike and spherical Au nanoparticles onto the column packing materials. While the overall particle gross sizes of these two shapes were similar, the baseline resolution was unfortunately not obtainable. However, the absorption spectra from the diode-array detector could be utilized to interpret the shapes of Au nanoparticles. The potential capability for the size separation of Au nanoparticles by size-exclusion chromatography with diode-array detection was also demonstrated. | Like any typical food system, bone soup (or broth), a traditional nourishing food in many cultures, contains a colloid dispersion of self-assembled micro/nano-particles. Food ingestion results in the direct contact of food colloidal MNPs with immune cells. Will they ever interact with each other? To answer the question, MNPs and NPs were separated from porcine bone soup and labeled with Nile Red, and their uptake by murine oral macrophages and its consequent effects were investigated. Colloidal particle samples of UF-MNPs and SEC-NP were prepared from porcine bone soup by ultrafiltration (UF) and size-exclusion chromatography, respectively. Their mean hydrodynamic diameters were 248 ± 10 nm and 170 ± 1 nm with dominant composition of protein and lipid. Particles in both samples were found to be internalized by oral macrophages upon co-incubation at particle/cell ratios of 14,000/1. In normal oral macrophages, the particle uptake exerted influence neither on the cellular cytosolic membrane potential (Vmem) nor mitochondrial superoxide level, as were indicated with fluorescent dyes of DiBAC4(3) and MitoSOX Red, respectively. However, when oral macrophages were challenged by peroxyl radical inducer AAPH, the engulfment of UF-MNPs and SEC-NPs mitigated the peroxyl radical induced membrane hyperpolarization effect by up to 70%, and the suppression on the oxygen respiration in mitochondria by up to 100%. Those results provide evidence of the direct interaction between food colloidal particles with immune cells, implying a possible new mode of food-body interaction. The uptake of food colloidal particles by oral macrophages can mitigate the peroxyl radical induced membrane hyperpolarization effect and suppress the oxygen respiration in mitochondria. Jianwu Zhou and coworkers from Zhejiang Gongshang University, China, separated micro/nano particles of 248 ± 10 nm and 170 ± 1 nm in diameter from porcine bone soup via membrane ultrafiltration and gel-filtration, respectively. By labeling the colloidal particles with hydrophobic fluorescent dyes, they tracked their internalization by oral macrophages upon co-incubation. It was found the food colloidal particles ingestion had no influence on the cell plasma membrane potential and mitochondrial superoxide level of the normal oral macrophages. However, when macrophages were irritated by peroxyl radical inducer 2,2′-azobis (2-amidinopropane) dihydrochloride, the food micro/nano particles exhibited a pacifying effect. This finding reveal a possible new mode of food-body interaction. | ABSTRACTUNC-45A is an ubiquitously expressed protein highly conserved throughout evolution. Most of what we currently know about UNC-45A pertains to its role as a regulator of the actomyosin system... | eng_Latn | 26,197 |
Human defensin 5 (HD5) is a broad-spectrum antibacterial peptide with a C-terminal active region. To promote the development of this peptide into an antibiotic, we initially substituted Glu21 with Arg because it is an electronegative residue located around the active region. Although detrimental to dimer formation, the E21R substitution markedly enhanced the antibacterial activity of HD5 and increased its ability to penetrate cell membranes, demonstrating that increasing the electropositive charge compensated for the effect of dimer disruption. Subsequently, a partial Arg scanning mutagenesis was performed, and Thr7 was selected for replacement with Arg to further strengthen the antibacterial activity. The newly designed peptide, T7E21R-HD5, exhibited potent antibacterial activity, even in saline and serum solutions. In contrast to monomeric E21R-HD5, T7E21R-HD5 assembled into an atypical dimer with parallel β strands, thus expanding the role of increasing electropositive charge in bactericidal activity and providing a useful guide for further defensin-derived antibiotic design. | Human α and β-defensins are cationic antimicrobial peptides characterized by three disulfide bonds with a triple stranded β-sheet motif. It is presumed that interaction with the bacterial cell surface and membrane permeabilization by defensins is an important step in the killing process. In this study, we have compared interactions of three human α-defensins HNP3, HNP4, HD5 and human β-defensins HBD1-4 that are active against Escherichia coli, with its cell surface and inner membrane as well as negatively charged model membranes. We have also included the inactive α-defensin HD6 in the study. Among the α-defensins, HNP4, HD5 and HD6 were more effective in increasing the zeta potential as compared to HNP3. Among the β-defensins, HBD1 was the least effective in increasing the zeta potential. The zeta potential modulation data indicate variations in the surface charge neutralizing ability of α- and β-defensins. Comparison of E. coli inner membrane and model membrane permeabilizing abilities indicated that HD5, HD6 and HBD1 do not permeabilize membranes. Although HBD4 does not permeabilize model membranes, considerable damage to the inner membrane of E. coli is observed. Our data indicate that mammalian defensins do not kill E. coli by a simple mechanism involving membrane permeabilization though their antibacterial potencies are very similar. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,198 |
Binding constants Kobs, expressed per site and evaluated in the limit of zero binding density, are quantified as functions of salt (sodium acetate) concentration for the interactions of the oligopeptide ligand KWK6NH2 (designated L8+, with ZL = 8 charges) with three single-stranded DNA oligomers (ss dT-mers, with |ZD| = 15, 39, and 69 charges). These results provide the first systematic experimental information about the effect of changing |ZD| on the strength and salt dependence of oligocation-oligonucleotide binding interactions. In a comparative study of L8+ binding to poly dT and to a short dT oligomer (|ZD| = 10),. Proc. Natl. Acad. Sci. USA. 93:2511-2516) demonstrated the profound thermodynamic effects of phosphate charges that flank isolated nonspecific L8+ binding sites on DNA. Here we find that both Kobs and the magnitude of its power dependence on salt activity (|SaKobs|) increase monotonically with increasing |ZD|. The dependences of Kobs and SaKobs on |ZD| are interpreted by introducing a simple two-state thermodynamic model for Coulombic end effects, which accounts for our finding that when L8+ binds to sufficiently long dT-mers, both DeltaGobso = -RT ln Kobs and SaKobs approach the values characteristic of binding to poly-dT as linear functions of the reciprocal of the number of potential oligocation binding sites on the DNA lattice. Analysis of our L8+-dT-mer binding data in terms of this model indicates that the axial range of the Coulombic end effect for ss DNA extends over approximately 10 phosphate charges. We conclude that Coulombic interactions cause an oligocation (with ZL < |ZD|) to bind preferentially to interior rather than terminal binding sites on oligoanionic or polyanionic DNA, and we quantify the strong increase of this preference with decreasing salt concentration. Coulombic end effects must be considered when oligonucleotides are used as models for polyanionic DNA in thermodynamic studies of the binding of charged ligands, including proteins. | Four 20 ns molecular dynamics simulations have been performed with two counterions, K+ or Na+, at two water contents, 15 or 20 H2O per nucleotide. A hexagonal simulation cell comprised of three identical DNA decamers [d(5′-ATGCAGTCAG) × d(5′-TGACTGCATC)] with periodic boundary condition along the DNA helix was used. The simulation setup mimics the DNA state in oriented DNA fibers or in crystals of DNA oligomers. Variation of counterion nature and water content do not alter averaged DNA structure. K+ and Na+ binding to DNA are different. K+ binds to the electronegative sites of DNA bases in the major and the minor grooves, while Na+ interacts preferentially with the phosphate groups. Increase of water causes a shift of both K+ and Na+ from the first hydration shell of O1P/O2P and of the DNA bases in the minor groove with lesser influence for the cation binding to the bases in the major groove. Mobility of both water and cations in the K–DNA systems is faster than in the Na–DNA systems: Na+ organizes and immobilizes water structure around itself and near DNA while for K+ water is less organized and more dynamic. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 26,199 |
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