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The Beilstein test is a simple qualitative chemical test for organic halides. It was developed by Friedrich Konrad Beilstein.
A copper wire is cleaned and heated in a Bunsen burner flame to form a coating of copper(II) oxide. It is then dipped in the sample to be tested and once again heated in a flame. A positive test is indicated by a green flame caused by the formation of a copper halide. The test does not detect fluorine/fluorides.
This test is no longer frequently used. One reason why it is not widely used is that it is possible to generate the highly toxic chloro-dioxins if the test material is a polychloroarene.
An alternative wet test for halide is the sodium fusion test — this test converts organic material to inorganic salts include the sodium halide. Addition of silver nitrate solution causes any halides to precipitate as the respective silver halide.
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Theoretical and Fundamental Chemistry
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Some old studies suggested that the ingestion of large doses of thiamine (vitamin B) could be effective as an oral insect repellent against mosquito bites. However, there is now conclusive evidence that thiamin has no efficacy against mosquito bites. Some claim that plants such as wormwood or sagewort, lemon balm, lemon grass, lemon thyme, and the mosquito plant (Pelargonium) will act against mosquitoes. However, scientists have determined that these plants are "effective" for a limited time only when the leaves are crushed and applied directly to the skin.
There are several, widespread, unproven theories about mosquito control, such as the assertion that vitamin B, in particular B (thiamine), garlic, ultrasonic devices or incense can be used to repel or control mosquitoes. Moreover, manufacturers of "mosquito repelling" ultrasonic devices have been found to be fraudulent, and their devices were deemed "useless" according to a review of scientific studies.
| 1 |
Applied and Interdisciplinary Chemistry
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The mechanism of nucleophilic epoxidation begins with conjugate addition of the peroxide (or other O-nucleophilic species) to the enone. Metal ions or conjugate acids present in solution coordinate both the peroxide oxygen and the enolate oxygen. Attack of the enolate on the peroxide oxygen generates the epoxide product and releases a leaving group.
Because the process is stepwise, the configuration of the carbon-carbon double bond is not necessarily preserved. Both cis and trans enones form trans epoxides under nearly all nucleophilic epoxidation conditions (methods employing lanthanide-BINOL systems are the exception).
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Theoretical and Fundamental Chemistry
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Digestion is the breakdown of carbohydrates to yield an energy-rich compound called ATP. The production of ATP is achieved through the oxidation of glucose molecules. In oxidation, the electrons are stripped from a glucose molecule to reduce NAD+ and FAD. NAD+ and FAD possess a high energy potential to drive the production of ATP in the electron transport chain. ATP production occurs in the mitochondria of the cell. There are two methods of producing ATP: aerobic and anaerobic.
In aerobic respiration, oxygen is required. Using oxygen increases ATP production from 4 ATP molecules to about 30 ATP molecules.
In anaerobic respiration, oxygen is not required. When oxygen is absent, the generation of ATP continues through fermentation. There are two types of fermentation: alcohol fermentation and lactic acid fermentation.
There are several different types of carbohydrates: polysaccharides (e.g., starch, amylopectin, glycogen, cellulose), monosaccharides (e.g., glucose, galactose, fructose, ribose) and the disaccharides (e.g., sucrose, maltose, lactose).
[https://www.ncbi.nlm.nih.gov/books/NBK459280/ Monosaccharides], also known as simple sugars, are the most basic, fundamental unit of a carbohydrate. These are simple sugars with the general chemical structure of C6H12O6.
[https://www.ncbi.nlm.nih.gov/books/NBK459280/ Disaccharides] are a type of carbohydrate. Disaccharides consist of compound sugars containing two monosaccharides with the elimination of a water molecule with the general chemical structure C12H22O11.
[https://www.ncbi.nlm.nih.gov/books/NBK459280/ Oligosaccharides] are carbohydrates that consist of a polymer that contains three to ten monosaccharides linked together by glycosidic bonds.
Glucose reacts with oxygen in the following reaction, CHO + 6O → 6CO + 6HO. Carbon dioxide and water are waste products, and the overall reaction is exothermic.
The reaction of glucose with oxygen releasing energy in the form of molecules of ATP is therefore one of the most important biochemical pathways found in living organisms.
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Applied and Interdisciplinary Chemistry
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The original Ternary complex model was used to describe ligand, receptor, and G-protein interactions. It uses equilibrium dissociation constants for the interactions between the receptor and each ligand (K for ligand A; K for ligand B), as well as a cooperativity factor (α) that denotes the mutual effect of the two ligands on each other's affinity for the receptor. An α > 1.0 refers to positive allosteric modulation, an α < 1.0 refers to negative allosteric modulation, and an α = 1.0 means that binding of either ligand to the receptor does not alter the affinity of the other ligand for the receptor (i.e., a neutral modulator). Further, the α parameter can be added as a subtle but highly useful extension to the ATCM in order to include effects of an allosteric modulator on the efficacy (as distinct from the affinity) of another ligand that binds the receptor, such as the orthosteric agonist. Some ligands can reduce the efficacy but increase the affinity of the orthosteric agonist for the receptor.
Although it is a simple assumption that the proportional amount of an active receptor state should correlate with the biological response, the experimental evidence for receptor overexpression and spare receptors suggests that the calculation of the net change in the active receptor state is a much better measure for response than is the fractional or proportional change. This is demonstrated by the effects of agonist/ antagonist combinations on the desensitization of receptors. This is also demonstrated by receptors that are activated by overexpression, since this requires a change between R and R* that is difficult to understand in terms of a proportional rather than a net change, and for the molecular model that fits with the mathematical model.
| 1 |
Applied and Interdisciplinary Chemistry
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Immunogold labeling was first used in 1971 by Faulk and Taylor to identify Salmonella antigens. It was first applied in transmission electron microscopy (TEM) and was especially useful in highlighting proteins found in low densities, such as some cell surface antigens. As the resolution of scanning electron microscopy (SEM) increased, so too did the need for nanoparticle-sized labels such as immunogold. In 1975, Horisberger and coworkers successfully visualised gold nanoparticles with a diameter of less than 30 nm
and this soon became an established SEM technique.
| 1 |
Applied and Interdisciplinary Chemistry
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Thermochromic ink (also called thermochromatic ink) is a type of dye that changes color in response to a change in temperature. It was first used in the 1970s in novelty toys like mood rings, but has found some practical uses in things such as thermometers, product packaging, and pens. The ink has also found applications within the medical field for specific medical simulations in medical training. Thermochromic ink can also turn transparent when heat is applied; an example of this type of ink can be found on the corners of an examination mark sheet to prove that the sheet has not been edited or photocopied.
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Theoretical and Fundamental Chemistry
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Amine oxides exhibit many kinds of reactions.
*Pyrolytic elimination. Amine oxides, when heated to 150–200 °C undergo a Cope reaction to form a hydroxylamine and an alkene. The reaction requires the alkyl groups to have hydrogens at the beta-carbon (i.e. works with ethyl and above, but not methyl)
*Reduction to amines. Amine oxides are readily converted to the parent amine by common reduction reagents including lithium aluminium hydride, sodium borohydride, catalytic reduction, zinc / acetic acid, and iron / acetic acid. Pyridine N-oxides can be deoxygenated by phosphorus oxychloride
* Sacrificial catalysis. Oxidants can be regenerated by reduction of N-oxides, as in the case of regeneration of osmium tetroxide by N-methylmorpholine N-oxide in the Upjohn dihydroxylation.
* O-Alkylation. Pyridine N-oxides react with alkyl halides to the O-alkylated product
* Bis-ter-pyridine derivatives adsorbed on silver surfaces are discussed to react with oxygen to bis-ter-pyridine N-oxide. This reaction can be followed by video-scanning tunneling microscopy with sub-molecular resolution.
* In the Meisenheimer rearrangement (after Jakob Meisenheimer) certain N-oxides rearrange to hydroxylamines
: in a 1,2-rearrangement:
:or a 2,3-rearrangement:
* In the Polonovski reaction a tertiary N-oxide is cleaved by acetic acid anhydride to the corresponding acetamide and aldehyde:
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Theoretical and Fundamental Chemistry
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The use of cloning for military purposes has also been explored in several fictional works. In Doctor Who, an alien race of armour-clad, warlike beings called Sontarans was introduced in the 1973 serial "The Time Warrior". Sontarans are depicted as squat, bald creatures who have been genetically engineered for combat. Their weak spot is a "probic vent", a small socket at the back of their neck which is associated with the cloning process. The concept of cloned soldiers being bred for combat was revisited in "The Doctors Daughter" (2008), when the Doctors DNA is used to create a female warrior called Jenny.
The 1977 film Star Wars was set against the backdrop of a historical conflict called the Clone Wars. The events of this war were not fully explored until the prequel films Attack of the Clones (2002) and Revenge of the Sith (2005), which depict a space war waged by a massive army of heavily armoured clone troopers that leads to the foundation of the Galactic Empire. Cloned soldiers are "manufactured" on an industrial scale, genetically conditioned for obedience and combat effectiveness. It is also revealed that the popular character Boba Fett originated as a clone of Jango Fett, a mercenary who served as the genetic template for the clone troopers.
| 1 |
Applied and Interdisciplinary Chemistry
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Biomarkers in analytical chemistry and in environmental science are chemicals, metabolites, susceptibility characteristics, or changes in the body that relate to the exposure of an organism to a chemical. They have the ability to identify if an exposure has occurred, the route of exposure, the pathway of exposure, and the resulting effects of the exposure. The use of biomarkers in exposure studies is also referred to as biomonitoring. When dealing with exposure assessment, there are three types of biomarkers that can be useful, biomarkers of susceptibility, biomarkers of exposure, and biomarkers of effect. Biomarkers of exposure are the most widely used because they can provide information on the route, pathway, and sometimes, even the source of exposure.
| 1 |
Applied and Interdisciplinary Chemistry
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While al-Kindi appreciated the usefulness of philosophy in answering questions of a religious nature, there would be many Islamic thinkers who were not as enthusiastic about its potential. But it would be incorrect to assume that they opposed philosophy simply because it was a "foreign science". Oliver Leaman, an expert on Islamic philosophy, points out that the objections of notable theologians are rarely directed at philosophy itself, but rather at the conclusions the philosophers arrived at. Even al-Ghazali, who is famous for his critique of the philosophers, was himself an expert in philosophy and logic. And his criticism was that they arrived at theologically erroneous conclusions. The three most serious of these, in his view, were believing in the co-eternity of the universe with God, denying the bodily resurrection, and asserting that God only has knowledge of abstract universals, not of particular things (not all philosophers subscribed to these same views).
During his life, al-Kindi was fortunate enough to enjoy the patronage of the Mutazilite Caliphs al-Mamun and al-Mutasim, which meant he could carry out his philosophical speculations with relative ease. In his own time, al-Kindi would be criticized for extolling the "intellect" as being the most immanent creation in proximity to God, which was commonly held to be the position of the angels. He also engaged in disputations with certain Mutazilites, whom he attacked for their belief in atoms, as not all Mutazilites accepted the belief of atomism. But the real role of al-Kindi in the conflict between philosophers and theologians would be to prepare the ground for debate. His works, says Deborah Black, contained all the seeds of future controversy that would be fully realized in al-Ghazalis Incoherence of the Philosophers'.
| 1 |
Applied and Interdisciplinary Chemistry
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Bacterial luciferin is two-component system consisting of flavin mononucleotide and a fatty aldehyde found in bioluminescent bacteria.
| 1 |
Applied and Interdisciplinary Chemistry
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The following table is a representative sample of Erwin Chargaffs 1952 data, listing the base composition of DNA from various organisms and support both of Chargaffs rules. An organism such as φX174 with significant variation from A/T and G/C equal to one, is indicative of single stranded DNA.
! scope=col|Organism!!scope=col|Taxon!!scope=col|%A !!scope=col|%G !!scope=col|%C !!scope=col|%T !!scope=col|A / T !!scope=col|G / C !!scope=col|%GC !!scope=col|%AT
| Maize || Zea || 26.8 || 22.8 || 23.2 || 27.2 || 0.99 || 0.98 || 46.1 || 54.0
| Octopus || Octopus || 33.2 || 17.6 || 17.6 || 31.6 || 1.05 || 1.00 || 35.2 || 64.8
| Chicken || Gallus || 28.0 || 22.0 || 21.6 || 28.4 || 0.99 || 1.02 || 43.7 || 56.4
| Rat || Rattus || 28.6 || 21.4 || 20.5 || 28.4 || 1.01 || 1.00 || 42.9 || 57.0
| Human || Homo || 29.3 || 20.7 || 20.0 || 30.0 || 0.98 || 1.04 || 40.7 || 59.3
| Grasshopper || Orthoptera || 29.3 || 20.5 || 20.7 || 29.3 || 1.00 || 0.99 || 41.2 || 58.6
| Sea urchin || Echinoidea || 32.8 || 17.7 || 17.3 || 32.1 || 1.02 || 1.02 || 35.0 || 64.9
| Wheat || Triticum || 27.3 || 22.7 || 22.8 || 27.1 || 1.01 || 1.00 || 45.5 || 54.4
| Yeast || Saccharomyces || 31.3 || 18.7 || 17.1 || 32.9 || 0.95 || 1.09 || 35.8 || 64.4
| E. coli || Escherichia || 24.7 || 26.0 || 25.7 || 23.6 || 1.05 || 1.01 || 51.7 || 48.3
| φX174 || PhiX174 || 24.0 || 23.3 || 21.5 || 31.2 || 0.77 || 1.08 || 44.8 || 55.2
| 1 |
Applied and Interdisciplinary Chemistry
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The general structure is RR′C(X)C(=O)R where R is an alkyl or aryl residue and X any one of the halogens.
The preferred conformation of a halo ketone is that of a cisoid with the halogen and carbonyl sharing the same plane as the steric hindrance with the carbonyl alkyl group is generally larger.
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Theoretical and Fundamental Chemistry
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As the first Ph.D. and full-time professor of biochemistry in Korea, Lee contributed to the establishment of biochemistry as a newly organized field of study in Korea.
He began with a study of glycolysis. In the late 1920s, the role of phosphorylated compounds in glycolysis had not yet been fully explained. Lee's work touched on early aspects of intermediary carbohydrate metabolism, which was also the subject of Nobel Prize-winning research by Otto Fritz Meyerhof, Otto Heinrich Warburg, and Hans Adolf Krebs.
Lee maintained an interest in factors affecting glucose metabolism upon his return to Korea, where he continued his research with published studies of the Korean diet. Building upon work begun in 1928, he investigated the problem of identifying and quantifying the nutritional elements of the staple Korean diet and its effects on metabolism. He identified nutritional sources in these foods for the healthy development of Korean children and adults during the Japanese occupation of Korea.
In addition to teaching and editing, Lee authored and co-authored at least 10 scientific papers and articles in several languages throughout his brief career. He did all of this despite working under conditions of widespread rationing at the end of World War II.
| 1 |
Applied and Interdisciplinary Chemistry
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Greek prefixes in alphabetical order indicate ring size.
This ring-size nomenclature stems from the fact that hydrolysis of an α-lactam gives an α-amino acid and that of a β-Lactam gives a β-amino acid, and so on.
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Theoretical and Fundamental Chemistry
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The structure of a gel network can be conceptualised as a random graph. This analogy is exploited to calculate the gel point and gel fraction for monomer precursors with arbitrary types of functional groups. Random graphs can be used to derive analytical expressions for simple polymerisation mechanisms, such as step-growth polymerisation, or alternatively, they can be combined with a system of rate equations that are integrated numerically.
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Theoretical and Fundamental Chemistry
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Unbound bilirubin (Bf) levels can be used to predict the risk of neurodevelopmental handicaps within infants. Unconjugated hyperbilirubinemia in a newborn can lead to accumulation of bilirubin in certain brain regions (particularly the basal nuclei) with consequent irreversible damage to these areas manifesting as various neurological deficits, seizures, abnormal reflexes and eye movements. This type of neurological injury is known as kernicterus. The spectrum of clinical effect is called bilirubin encephalopathy. The neurotoxicity of neonatal hyperbilirubinemia manifests because the blood–brain barrier has yet to develop fully, and bilirubin can freely pass into the brain interstitium, whereas more developed individuals with increased bilirubin in the blood are protected. Aside from specific chronic medical conditions that may lead to hyperbilirubinemia, neonates in general are at increased risk since they lack the intestinal bacteria that facilitate the breakdown and excretion of conjugated bilirubin in the feces (this is largely why the feces of a neonate are paler than those of an adult). Instead the conjugated bilirubin is converted back into the unconjugated form by the enzyme β-glucuronidase (in the gut, this enzyme is located in the brush border of the lining intestinal cells) and a large proportion is reabsorbed through the enterohepatic circulation. In addition, recent studies point towards high total bilirubin levels as a cause for gallstones regardless of gender or age.
| 1 |
Applied and Interdisciplinary Chemistry
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The steps for naming molecules using the CIP system are often presented as:
# Identification of stereocenters and double bonds;
# Assignment of priorities to the groups attached to each stereocenter or double-bonded atom; and
# Assignment of R/S and E/Z descriptors.
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Theoretical and Fundamental Chemistry
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According to the US Energy Information Administration (EIA) estimate for 2017, the world consumes 98.8 million barrels of oil each day.
This table orders the amount of petroleum consumed in 2011 in thousand barrels (1000 bbl) per day and in thousand cubic metres (1000 m) per day:
Source: [http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=5&pid=5&aid=2 US Energy Information Administration]
Population Data:
peak production of oil already passed in this state</small>
This country is not a major oil producer</small>
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Theoretical and Fundamental Chemistry
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Unlike conventional evolutionary and biochemical approaches to studying proteins, i.e. the so-called horizontal comparison of related protein homologues from different branch ends of the tree of life; ASR probes the statistically inferred ancestral proteins within the nodes of the tree – in a vertical manner (see diagram, right). This approach gives access to protein properties that may have transiently arisen over evolutionary time and has recently been used as a way to infer the potential selection pressures that resulted in present-day sequences. ASR has been used to probe the causative mutation that resulted in a proteins neofunctionalization after duplication by first determining that said mutation was located between ancestors 5 and 4 on the diagram (illustratively) using functional assays. In the field of protein biophysics, ASR has also been used to study the development of a proteins thermodynamic and kinetic landscapes over evolutionary time as well as protein folding pathways by combining many modern day analytical techniques such as HX/MS. These sort of insights are typically inferred from several ancestors reconstructed along a phylogeny – referring to the previous analogy, by studying nodes higher and higher (further and further back in evolutionary time) within the tree of life.
Most ASR studies are conducted in vitro, and have revealed ancestral protein properties that seem to be evolutionarily desirable traits – such as increased thermostability, catalytic activity and catalytic promiscuity. These data have been accredited to artifacts of the ASR algorithms, as well as indicative illustrations of ancient Earths environment – often, ASR research must be complemented with extensive controls (usually alternate ASR experiments) to mitigate algorithmic error. Not all studied ASR proteins exhibit this so-called ancestral superiority. The nascent field of evolutionary biochemistry has been bolstered by the recent increase in ASR studies using the ancestors as ways to probe organismal fitness within certain cellular contexts – effectively testing ancestral proteins in vivo. Due to inherent limitations in these sorts of studies – primarily being the lack of suitably ancient genomes to fit these ancestors in to, the small repertoire of well categorised laboratory model systems, and the inability to mimic ancient cellular environments; very few ASR studies in vivo have been conducted. Despite the above mentioned obstacles, preliminary insights into this avenue of research from a 2015 paper, have revealed that observed ancestral superiority in vitro were not recapitulated in vivo of a given protein. ASR presents one of a few mechanisms to study biochemistry of the Precambrian era of life (>541Ma) and is hence often used in paleogenetics; indeed Zuckerkandl and Pauling originally intended ASR to be the starting point of a field they termed Paleobiochemistry'.
| 1 |
Applied and Interdisciplinary Chemistry
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Metro and light rail sides of operation vary and might not match railways or roads in their country. Some systems where the metro matches the side of the national rail network but not the roads include those in Bilbao, Buenos Aires, Cairo, Catania, Jakarta, Lisbon, Lyon, Naples, and Rome. A small number of cities, including Madrid and Stockholm, originally ran on the same side as road traffic when the systems opened in 1919 and 1950 respectively, but had road traffic change in 1924 and 1967 respectively. Conversely, metros in France (except for the aforementioned Lyon) and mainland China run on the right just like roads, while mainline trains run on the left.
A small number of systems have situational reasons to differ from the norm. On the MTR in Hong Kong, the section originally known as the Ma On Shan line (now part of the Tuen Ma line) runs on the right to make interchanging with the East Rail line easier, while the rest of the system runs on the left. On the Seoul Metropolitan Subway, lines that integrate with Korail (except Line 3, which is disconnected from the rest of the network) run on the left, while the lines that are not run on the right. In Nizhny Novgorod, Line 2 runs on the left due to the track layout when it first opened as a branch of Line 1. In Lima, Line 1 runs entirely on the left, while Line 2 runs entirely on the right.
Metro Line M1 in Budapest is the only metro line to have switched sides. It originally ran on the left but switched to right hand-running during the line's reconstruction around 1973.
Because trams frequently operate on roads, they generally operate on the same side as other road traffic.
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Theoretical and Fundamental Chemistry
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The G-less cassette transcription assay is a method used in molecular biology to determine promoter strength in vitro. The technique involves quantification of an mRNA product with the use of a plasmid. The G-less cassette is part of a pre-constructed vector, usually containing a multiple cloning site (MCS) upstream of the cassette. For this reason, promoters of interest can be inserted directly into the MCS to ultimately measure the accuracy and efficiency of a promoter in recruiting transcription machinery.
| 1 |
Applied and Interdisciplinary Chemistry
|
An inhibitor is usually a material added in a small quantity to a particular environment that reduces the rate of corrosion. They may be classified a number of ways but are usually 1) Oxidizing; 2) Scavenging; 3) Vapor-phase inhibitors; Sometimes they are called Volatile corrosion inhibitor 4) Adsorption inhibitors; 5) Hydrogen-evolution retarder. Another way to classify them is chemically. As there is more concern for the environment and people are more keen to use Renewable resources, there is ongoing research to modify these materials so they may be used as corrosion inhibitors.
| 1 |
Applied and Interdisciplinary Chemistry
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His first academic appointment was at the University of Adelaide and then in 1958 he rejoined Dwyer at the Australian National University.
Sargeson was best known as a coordination chemist with an interest in bioinorganic chemistry. In early work with Dwyer and throughout his career, he studied stereochemistry. His research group investigated the reactions of amine ligands, culminating in the synthesis of the clathrochelates called "sepulchrates".
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Theoretical and Fundamental Chemistry
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All monosaccharides are reducing sugars because they either have an aldehyde group (if they are aldoses) or can tautomerize in solution to form an aldehyde group (if they are ketoses). This includes common monosaccharides like galactose, glucose, glyceraldehyde, fructose, ribose, and xylose.
Many disaccharides, like cellobiose, lactose, and maltose, also have a reducing form, as one of the two units may have an open-chain form with an aldehyde group. However, sucrose and trehalose, in which the anomeric carbon atoms of the two units are linked together, are nonreducing disaccharides since neither of the rings is capable of opening.
In glucose polymers such as starch and starch-derivatives like glucose syrup, maltodextrin and dextrin the macromolecule begins with a reducing sugar, a free aldehyde. When starch has been partially hydrolyzed the chains have been split and hence it contains more reducing sugars per gram. The percentage of reducing sugars present in these starch derivatives is called dextrose equivalent (DE).
Glycogen is a highly branched polymer of glucose that serves as the main form of carbohydrate storage in animals. It is a reducing sugar with only one reducing end, no matter how large the glycogen molecule is or how many branches it has (note, however, that the unique reducing end is usually covalently linked to glycogenin and will therefore not be reducing). Each branch ends in a nonreducing sugar residue. When glycogen is broken down to be used as an energy source, glucose units are removed one at a time from the nonreducing ends by enzymes.
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Theoretical and Fundamental Chemistry
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Photoreceptor proteins are light-sensitive proteins involved in the sensing and response to light in a variety of organisms. Some examples are rhodopsin in the photoreceptor cells of the vertebrate retina, phytochrome in plants, and bacteriorhodopsin and bacteriophytochromes in some bacteria. They mediate light responses as varied as visual perception, phototropism and phototaxis, as well as responses to light-dark cycles such as circadian rhythm and other photoperiodisms including control of flowering times in plants and mating seasons in animals.
| 1 |
Applied and Interdisciplinary Chemistry
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ECS publishes peer-reviewed technical journals, proceedings, monographs, conference abstracts, and a quarterly news magazine.
| 0 |
Theoretical and Fundamental Chemistry
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In the United States, the ECOTOX, ERED (sediment) and Toxicity Residue Databases are used by many regulatory agencies such as state environmental quality agencies and the EPA to determine regulatory environmental toxicant concentration levels. Under the Clean Water Act the EPA has used the ECOTOX database among other information to set wastewater toxicant concentration standards for industry as well as water quality standards for all contaminants in surface waters. Under the CWA, individual states must regulate water quality criteria at or below the concentrations set forth by the EPA. Sediment toxicant concentrations, however, are generally not regulated in the same way. The determination of sediment quality criteria and sediment toxicity testing is highly complex and is often regulated by states or some state run environmental agency. Sediment toxicity evaluations of contaminated sediments are very site specific and toxicant effect levels are often much more variable than those of surface waters. For this reason it may be nearly impossible to develop feasible acceptable sediment concentration regulations that apply to all aquatic systems or regions.
Acceptable concentrations or sediment quality guidelines have been developed and are used in risk assessments and the management of dredged materials. "Sediment quality guidelines" (SQGs), as defined at the 2002 Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop, are numerical chemical concentrations intended to be either protective of biological resources, or predictive of adverse effects to those resources, or both. SQGs for assessing sediment quality relative to the potential for adverse effects on sediment-dwelling organisms have been derived using both mechanistic and empirical approaches.
| 1 |
Applied and Interdisciplinary Chemistry
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Gestonorone caproate, also known as norhydroxyprogesterone caproate, 17α-hydroxy-19-norprogesterone 17α-hexanoate, or 17α-hydroxy-19-norpregn-4-ene-3,20-dione 17α-hexanoate, is a synthetic norpregnane steroid and a derivative of progesterone. It is specifically a combined derivative of 17α-hydroxyprogesterone and 19-norprogesterone, or of gestronol (17α-hydroxy-19-norprogesterone), with a hexanoate (caproate) ester at the C17α position. Analogues and derivatives of gestonorone caproate include algestone acetophenide (dihydroxyprogesterone acetophenide), demegestone, nomegestrol acetate, norgestomet, and segesterone acetate, as well as 18-methylsegesterone acetate and the caproate esters chlormadinone caproate, hydroxyprogesterone caproate, medroxyprogesterone caproate, megestrol caproate, and methenmadinone caproate.
| 0 |
Theoretical and Fundamental Chemistry
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Exact solutions to the Boltzmann equations have been proven to exist in some cases; this analytical approach provides insight, but is not generally usable in practical problems.
Instead, numerical methods (including finite elements and lattice Boltzmann methods) are generally used to find approximate solutions to the various forms of the Boltzmann equation. Example applications range from hypersonic aerodynamics in rarefied gas flows to plasma flows. An application of the Boltzmann equation in electrodynamics is the calculation of the electrical conductivity - the result is in leading order identical with the semiclassical result.
Close to local equilibrium, solution of the Boltzmann equation can be represented by an asymptotic expansion in powers of Knudsen number (the Chapman–Enskog expansion). The first two terms of this expansion give the Euler equations and the Navier–Stokes equations. The higher terms have singularities. The problem of developing mathematically the limiting processes, which lead from the atomistic view (represented by Boltzmanns equation) to the laws of motion of continua, is an important part of Hilberts sixth problem.
| 1 |
Applied and Interdisciplinary Chemistry
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Exenatide is a 39-amino-acid peptide that is a synthetic version of exendin-4, a hormone found in the saliva of the Gila monster. It is used to treat Type II Diabetes as an adjunct to insulin and other drugs. It is GLP-1 receptor agonist that was first isolated by John Eng in 1992 while working at the Veterans Administration Medical Center in the Bronx, New York.
| 1 |
Applied and Interdisciplinary Chemistry
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Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is deoxyribose, a variant of ribose, the polymer is DNA.
Nucleic acids are chemical compounds that are found in nature. They carry information in cells and make up genetic material. These acids are very common in all living things, where they create, encode, and store information in every living cell of every life-form on Earth. In turn, they send and express that information inside and outside the cell nucleus. From the inner workings of the cell to the young of a living thing, they contain and provide information via the nucleic acid sequence. This gives the RNA and DNA their unmistakable ladder-step order of nucleotides within their molecules. Both play a crucial role in directing protein synthesis.
Strings of nucleotides are bonded to form spiraling backbones and assembled into chains of bases or base-pairs selected from the five primary, or canonical, nucleobases. RNA usually forms a chain of single bases, whereas DNA forms a chain of base pairs. The bases found in RNA and DNA are: adenine, cytosine, guanine, thymine, and uracil. Thymine occurs only in DNA and uracil only in RNA. Using amino acids and protein synthesis, the specific sequence in DNA of these nucleobase-pairs helps to keep and send coded instructions as genes. In RNA, base-pair sequencing helps to make new proteins that determine most chemical processes of all life forms.
| 1 |
Applied and Interdisciplinary Chemistry
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Flutamide was studied for the treatment of advanced breast cancer in two phase II clinical trials but was found to be ineffective. Out of a total of 47 patients, only three short-term responses occurred. However, the patients in the studies were selected irrespective of AR, , , or HER2 status, which were all unknown.
| 0 |
Theoretical and Fundamental Chemistry
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The simplest materials characterization is the residue remaining after a reaction. For example, a combustion reaction could be tested by loading a sample into a thermogravimetric analyzer at normal conditions. The thermogravimetric analyzer would cause ion combustion in the sample by heating it beyond its ignition temperature. The resultant TGA curve plotted with the y-axis as a percentage of initial mass would show the residue at the final point of the curve.
Oxidative mass losses are the most common observable losses in TGA.
Studying the resistance to oxidation in copper alloys is very important. For example, NASA (National Aeronautics and Space Administration) is conducting research on advanced copper alloys for their possible use in combustion engines. However, oxidative degradation can occur in these alloys as copper oxides form in atmospheres that are rich in oxygen. Resistance to oxidation is significant because NASA wants to be able to reuse shuttle materials. TGA can be used to study the static oxidation of materials such as these for practical use.
Combustion during TG analysis is identifiable by distinct traces made in the TGA thermograms produced. One interesting example occurs with samples of as-produced unpurified carbon nanotubes that have a large amount of metal catalyst present. Due to combustion, a TGA trace can deviate from the normal form of a well-behaved function. This phenomenon arises from a rapid temperature change. When the weight and temperature are plotted versus time, a dramatic slope change in the first derivative plot is concurrent with the mass loss of the sample and the sudden increase in temperature seen by the thermocouple. The mass loss could result from particles of smoke released from burning caused by inconsistencies in the material itself, beyond the oxidation of carbon due to poorly controlled weight loss.
Different weight losses on the same sample at different points can also be used as a diagnosis of the sample's anisotropy. For instance, sampling the top side and the bottom side of a sample with dispersed particles inside can be useful to detect sedimentation, as thermograms will not overlap but will show a gap between them if the particle distribution is different from side to side.
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Theoretical and Fundamental Chemistry
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DMSO is a widely used solvent.
The sulfoxide functional group occurs in several drugs. Notable is esomeprazole, the optically pure form of the proton-pump inhibitor omeprazole. Another commercially important sulfoxides include armodafinil.
Methionine sulfoxide forms from the amino acid methionine and its accumulation is associated with aging. The enzyme DMSO reductase catalyzes the interconversion of DMSO and dimethylsulfide.
Naturally-occurring chiral sulfoxides include alliin and ajoene.
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Theoretical and Fundamental Chemistry
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Carbon satellites in physics and spectroscopy, are small peaks that can be seen shouldering the main peaks in the nuclear magnetic resonance (NMR) spectrum. These peaks can occur in the NMR spectrum of any NMR active atom (e.g. F or P NMR) where those atoms adjoin a carbon atom (and where the spectrum is not C-decoupled, which is usually the case). However, Carbon satellites are most often encountered in proton NMR.
In the example of proton NMR, these peaks are not the result of proton-proton coupling, but result from the coupling of H atoms to an adjoining C atom. These small peaks are known as carbon satellites as they are small and appear around the main H peak i.e. satellite (around) to them. Carbon satellites are small because C only makes up about 1% of the atomic carbon content of carbon, the rest of the carbon atoms are predominantly NMR inactive C. Carbon satellites always appear as an evenly spaced pair around the main H peak. This is because they are the result of 1% of the H atoms coupling to an adjoined C atom to give a wide doublet (C has a spin of a half). Note, if the main H-peak has proton-proton coupling, then each satellite will be a miniature version of the main peak and will also show this H-coupling, e.g. if the main H-peak is a doublet, then the carbon satellites will appear as miniature doublets, i.e. one doublet on either side of the main H-peak.
For other NMR atoms (e.g. F or P atoms), the same applies as above, but obviously where the proton atom is replaced with that other NMR active atom e.g. P.
Sometime other peaks can be seen around H peaks; these are known as spinning sidebands and are related to the rate of spin of an NMR tube. Carbon satellites (and spinning sidebands) should not be confused with impurity peaks.
| 0 |
Theoretical and Fundamental Chemistry
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Animal and human data have revealed evidence of harm to the embryo and teratogenicity associated with ACE inhibitors.
| 0 |
Theoretical and Fundamental Chemistry
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Nanofluids poses the following advantages as compared to conventional fluids which makes them suitable for use in solar collectors:
*Absorption of solar energy will be maximized with change of the size, shape, material and volume fraction of the nanoparticles.
*The suspended nanoparticles increase the surface area but decrease the heat capacity of the fluid due to the very small particle size.
*The suspended nanoparticles enhance the thermal conductivity which results improvement in efficiency of heat transfer systems.
*Properties of fluid can be changed by varying concentration of nanoparticles.
*Extremely small size of nanoparticles ideally allows them to pass through pumps.
*Nanofluid can be optically selective (high absorption in the solar range and low emittance in the infrared.
The fundamental difference between the conventional and nanofluid-based collector lies in the mode of heating of the working fluid. In the former case the sunlight is absorbed by a surface, where as in the latter case the sunlight is directly absorbed by the working fluid (through radiative transfer). On reaching the receiver the solar radiations transfer energy to the nanofluid via scattering and absorption.
| 0 |
Theoretical and Fundamental Chemistry
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Spectrum analysis can be used at audio frequencies to analyse the harmonics of an audio signal. A typical application is to measure the distortion of a nominally sinewave signal; a very-low-distortion sinewave is used as the input to equipment under test, and a spectrum analyser can examine the output, which will have added distortion products, and determine the percentage distortion at each harmonic of the fundamental. Such analysers were at one time described as "wave analysers". Analysis can be carried out by a general-purpose digital computer with a sound card selected for suitable performance and appropriate software. Instead of using a low-distortion sinewave, the input can be subtracted from the output, attenuated and phase-corrected, to give only the added distortion and noise, which can be analysed.
An alternative technique, total harmonic distortion measurement, cancels out the fundamental with a notch filter and measures the total remaining signal, which is total harmonic distortion plus noise; it does not give the harmonic-by-harmonic detail of an analyser.
Spectrum analyzers are also used by audio engineers to assess their work. In these applications, the spectrum analyzer will show volume levels of frequency bands across the typical range of human hearing, rather than displaying a wave. In live sound applications, engineers can use them to pinpoint feedback.
| 0 |
Theoretical and Fundamental Chemistry
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His first post was with the Atomic Energy Research Establishment (AERE) near the village of Harwell where he lived, working at the Wantage Research Laboratory, then in Berkshire. His early work started an interest in radioisotopes and trace elements that he maintained throughout his working life. While at AERE, he spent several months in 1956 attending the British nuclear tests at Maralinga in Australia to study the environmental effects of radiation.
Bowen realized that the calibration of different instruments intended to measure trace elements was an important issue that needed addressing. His solution was to produce a good supply of a material which later become known as Bowens Kale'. This was a dried, crushed chomogenate of the plant kale, that was stable and consistent enough to be distributed as a research calibration standard - probably the first successful example of such a standard.
In 1964, he was appointed as a lecturer in the chemistry department at the University of Reading. Later he was promoted to Reader in analytical chemistry in 1974. At Reading, Bowen undertook consultancy for Dunlop, investigating potential uses for their products. When the Torrey Canyon oil disaster occurred in 1967, he realized that it might be possible to use foam booms to block the oil from spreading in the English Channel. His original experiments were conducted in a small bucket in his laboratory. Although not entirely successful in reality at the time due to the rough seas, this lateral thinking combined his interest in chemistry with his love of nature and has since been effectively deployed to protect ports and harbours against encroaching oil slicks. Bowen wrote a number of professional books in the field of chemistry, including two editions of Trace elements in Biochemistry (1966 and 1976).
In 1968, Bowen noted that the paint used for yellow line road markings can contain chromate pigment, which may cause urban pollution as it deteriorates. He pointed out that hexavalent chromium in dust can cause dermatitis ulceration on the skin, inflammation of the nasal mucosa and larynx, and lung cancer.
From 1951 onwards, Bowen was a long-serving member of the Botanical Society of the British Isles (BSBI). He was meetings secretary for a period and the official recorder of plants for the counties of Berkshire and Dorset, producing Floras for both counties. He retired to Winterborne Kingston in Dorset at the end of his life. He was also one of the leading contributors of botanical data for the Flora of Oxfordshire. He acted as an expert botanical guide on tours around Europe, especially Greece and Turkey.
Humphry Bowen donated a large collection of lichens from Berkshire and Oxfordshire to the Museum of Reading in the 1970s. He established the Bowen Cup at the University of Reading in 1988, an annual prize for the student in the Department of Chemistry at the University who achieves the top marks in Part II Analytical Chemistry.
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Theoretical and Fundamental Chemistry
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In organic chemistry, alkylimino-de-oxo-bisubstitution is the organic reaction of carbonyl compounds with amines to imines. The reaction name is based on the IUPAC Nomenclature for Transformations. The reaction is acid catalyzed and the reaction type is nucleophilic addition of the amine to the carbonyl compound followed by transfer of a proton from nitrogen to oxygen to a stable hemiaminal or carbinolamine. With primary amines water is lost in an elimination reaction to an imine. With aryl amines especially stable Schiff bases are formed.
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Theoretical and Fundamental Chemistry
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The concept dates to the 1950s, and was strongly advocated by Hans Bethe during the 1970s. At that time the first powerful fusion experiments were being built, but it would still be many years before they could be economically competitive. Hybrids were proposed as a way of greatly accelerating their market introduction, producing energy even before the fusion systems reached break-even. However, detailed studies of the economics of the systems suggested they could not compete with existing fission reactors.
The idea was abandoned and lay dormant until the 2000s, when the continued delays in reaching break-even led to a brief revival around 2009. These studies generally concentrated on the nuclear waste disposal aspects of the design, as opposed to the production of energy. The concept has seen cyclical interest since then, based largely on the success or failure of more conventional solutions like the Yucca Mountain nuclear waste repository
Another major design effort for energy production was started at Lawrence Livermore National Laboratory (LLNL) under their LIFE program. Industry input led to the abandonment of the hybrid approach for LIFE, which was then re-designed as a pure-fusion system. LIFE was cancelled when the underlying technology, from the National Ignition Facility, failed to reach its design performance goals.
Apollo Fusion, a company founded by Google executive Mike Cassidy in 2017, was also reported to be focused on using the subcritical nuclear fusion-fission hybrid method. Their web site is now focussed on their hall effect thrusters, and mentions fusion only in passing.
On 2022, September 9, Professor Peng Xianjue of the Chinese Academy of Engineering Physics announced that the Chinese government had approved the construction of the worlds largest pulsed-powerplant - the Z-FFR, namely Z(-pinch)-Fission-Fusion Reactor- in Chengdu, Sichuan province. Neutrons produced in a Z-pinch facility (endowed with cylindrical symmetry and fuelled with deuterium and tritium) will strike a coaxial blanket including both uranium and lithium isotopes. Uranium fission will boost the facilitys overall heat output by 10 to 20 times. Interaction of lithium and neutrons will provide tritium for further fueling. Innovative, quasi-spherical geometry near the core of Z-FFR leads to high performance of Z-pinch discharge. According to Prof. Xianjue, this will considerably speed up the use of fusion energy and prepare it for commercial power production by 2035.
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Theoretical and Fundamental Chemistry
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Solar-blind imaging can be used to detect corona discharge, in electrical infrastructure. Missile exhaust can be detected from the troposphere or ground. Also when looking down on the Earth from space, the Earth appears dark in this range, so rockets can be easily detected from above once they pass the ozone layer.
Israel, People's Republic of China, Russia, South Africa, United Kingdom, and United States are developing this technology.
| 0 |
Theoretical and Fundamental Chemistry
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When the analysis is looking for bacterial species that grow poorly in air, the initial analysis is done by mixing serial dilutions of the sample in liquid nutrient agar which is then poured into bottles which are then sealed and laid on their sides to produce a sloping agar surface. Colonies that develop in the body of the medium can be counted by eye after incubation.
The total number of colonies is referred to as the total viable count (TVC). The unit of measurement is cfu/ml (or colony forming units per millilitre) and relates to the original sample. Calculation of this is a multiple of the counted number of colonies multiplied by the dilution used.
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Theoretical and Fundamental Chemistry
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The ability of an engineered biomaterial to induce a physiological response that is supportive of the biomaterials function and performance is known as bioactivity. Most commonly, in bioactive glasses and bioactive ceramics this term refers to the ability of implanted materials to bond well with surrounding tissue in either osteo conductive or osseo productive roles. Bone implant materials are often designed to promote bone growth while dissolving into surrounding body fluid. Thus for many biomaterials good biocompatibility along with good strength and dissolution rates are desirable. Commonly, bioactivity of biomaterials is gauged by the surface biomineralization in which a native layer of hydroxyapatite is formed at the surface. These days, the development of clinically useful biomaterials is greatly enhanced by the advent of computational routines that can predict the molecular effects of biomaterials in a therapeutic setting based on limited in vitro' experimentation.
| 1 |
Applied and Interdisciplinary Chemistry
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Maxwell Garnett Equation describes optical properties of nanocomposites which consist in a collection of perfectly spherical nanoparticles. All these nanoparticles must have the same size. However, due to confinement effect, the optical properties can be influenced by the nanoparticles size distribution. As shown by Battie et al., the Maxwell Garnett equation can be generalized to take into account this distribution.
and are the nanoparticle radius and size distribution, respectively. and are the mean radius and the volume fraction of the nanoparticles, respectively. is the first electric Mie coefficient.
This equation reveals that the classical Maxwell Garnett equation gives a false estimation of the volume fraction nanoparticles when the size distribution cannot be neglected.
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Theoretical and Fundamental Chemistry
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Resonance (or delocalization) energy is the amount of energy needed to convert the true delocalized structure into that of the most stable contributing structure. The empirical resonance energy can be estimated by comparing the enthalpy change of hydrogenation of the real substance with that estimated for the contributing structure.
The complete hydrogenation of benzene to cyclohexane via 1,3-cyclohexadiene and cyclohexene is exothermic; 1 mole of benzene delivers 208.4 kJ (49.8 kcal).
Hydrogenation of one mole of double bonds delivers 119.7 kJ (28.6 kcal), as can be deduced from the last step, the hydrogenation of cyclohexene. In benzene, however, 23.4 kJ (5.6 kcal) are needed to hydrogenate one mole of double bonds. The difference, being 143.1 kJ (34.2 kcal), is the empirical resonance energy of benzene. Because 1,3-cyclohexadiene also has a small delocalization energy (7.6 kJ or 1.8 kcal/mol) the net resonance energy, relative to the localized cyclohexatriene, is a bit higher: 151 kJ or 36 kcal/mol.
This measured resonance energy is also the difference between the hydrogenation energy of three non-resonance double bonds and the measured hydrogenation energy:
:(3 × 119.7) − 208.4 = 150.7 kJ/mol (36 kcal).
Regardless of their exact values, resonance energies of various related compounds provide insights into their bonding. The resonance energies for pyrrole, thiophene, and furan are, respectively, 88, 121, and
67 kJ/mol (21, 29, and 16 kcal/mol). Thus, these heterocycles are far less aromatic than benzene, as is manifested in the lability of these rings.
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Theoretical and Fundamental Chemistry
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The largest natural contributor to public radiation dose is radon, a naturally occurring, radioactive gas found in soil and rock, which comprises approximately 55% of the annual background dose.
Radon gas levels vary by locality and the composition of the underlying soil and rocks.
Radon (at concentrations encountered in mines) was recognized as carcinogenic in the 1980s, in view of the lung cancer statistics for miners' cohorts.
Although radon may present significant risks, thousands of persons annually go to radon-contaminated mines for deliberate exposure to help with the symptoms of arthritis without any serious health effects.
Radon as a terrestrial source of background radiation is of particular concern because, although overall very rare, where it does occur it often does so in high concentrations. Some of these areas, including parts of Cornwall and Aberdeenshire have high enough natural radiation levels that nuclear licensed sites cannot be built there—the sites would already exceed legal limits before they opened, and the natural topsoil and rock would all have to be disposed of as low-level nuclear waste.
People in affected localities can receive up to 10 mSv per year background radiation.
This led to a health policy problem: what is the health impact of exposure to radon concentrations (100 Bq/m) typically found in some buildings?
| 1 |
Applied and Interdisciplinary Chemistry
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The funeral was large. The newspapers carried tributes and subsequently lengthier obituaries from learned societies were published, such as that in the Australian Medical Journal and elsewhere. The Melbourne Leader described the funeral: "The coffin was drawn by four horses. Four mourning coaches contained the chief mourners and the more intimate friends of the deceased gentleman. A large procession followed, in which were several members of Parliament, the members of the Royal Society, the Chief Justice; the Mayor and corporation of the city of Melbourne. A number of private carriages and the public wound up the procession....At the University, the chancellor, the vice-chancellor, and a number of the students, all in their academic robes, met the funeral cortege, and proceeded the remainder of the distance". The chief mourner was his youngest brother, George Robert Macadam (1837-1918). John Macadam's grave, surmounted by a marble obelisk, is in Melbourne General Cemetery.
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Theoretical and Fundamental Chemistry
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The charge of proteins is determined by the pKa of its amino acid side chains, and the terminal amino acid and carboxylic acid. Proteins with isoelectric point (pI) above physiological conditions have a positive charge and proteins with pI below physiological conditions have a negative charge. The net charge of the protein, determined by the sum charge of its constituents, results in electrophoretic migration in a physiologic electric field. These effects are short-range because of the high di-electric constant of water, however, once the protein is close to a charged surface, electrostatic coupling becomes the dominant force.
| 1 |
Applied and Interdisciplinary Chemistry
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An Environmental hazard can be defined as any condition, process, or state adversely affecting the environment. These hazards can be physical or chemical, and present in air, water, and/or soil. These conditions can cause extensive harm to humans and other organisms within an ecosystem.
| 1 |
Applied and Interdisciplinary Chemistry
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The principal environmental issues associated with runoff are the impacts to surface water, groundwater and soil through transport of water pollutants to these systems. Ultimately these consequences translate into human health risk, ecosystem disturbance and aesthetic impact to water resources. Some of the contaminants that create the greatest impact to surface waters arising from runoff are petroleum substances, herbicides and fertilizers. Quantitative uptake by surface runoff of pesticides and other contaminants has been studied since the 1960s, and early on contact of pesticides with water was known to enhance phytotoxicity. In the case of surface waters, the impacts translate to water pollution, since the streams and rivers have received runoff carrying various chemicals or sediments. When surface waters are used as potable water supplies, they can be compromised regarding health risks and drinking water aesthetics (that is, odor, color and turbidity effects). Contaminated surface waters risk altering the metabolic processes of the aquatic species that they host; these alterations can lead to death, such as fish kills, or alter the balance of populations present. Other specific impacts are on animal mating, spawning, egg and larvae viability, juvenile survival and plant productivity. Some research shows surface runoff of pesticides, such as DDT, can alter the gender of fish species genetically, which transforms male into female fish.
Surface runoff occurring within forests can supply lakes with high loads of mineral nitrogen and phosphorus leading to eutrophication. Runoff waters within coniferous forests are also enriched with humic acids and can lead to humification of water bodies Additionally, high standing and young islands in the tropics and subtropics can undergo high soil erosion rates and also contribute large material fluxes to the coastal ocean. Such land derived runoff of sediment nutrients, carbon, and contaminants can have large impacts on global biogeochemical cycles and marine and coastal ecosystems.
In the case of groundwater, the main issue is contamination of drinking water, if the aquifer is abstracted for human use. Regarding soil contamination, runoff waters can have two important pathways of concern. Firstly, runoff water can extract soil contaminants and carry them in the form of water pollution to even more sensitive aquatic habitats. Secondly, runoff can deposit contaminants on pristine soils, creating health or ecological consequences.
| 1 |
Applied and Interdisciplinary Chemistry
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In June 2021, Josh Carpenter was [https://www.al.com/news/birmingham/2021/05/southern-research-selects-new-president-and-ceo.html named president and CEO of Southern Research.] Before joining Southern Research, Carpenter served as director of the Innovation and Economic Opportunity Department for the City of Birmingham, where he led the city's efforts in workforce development, COVID recovery and business expansion. Previously, he worked as the director of External Affairs at the University of Alabama at Birmingham, as an assistant professor of economics at UAB and as a non-resident senior fellow at The Brookings Institution.
| 1 |
Applied and Interdisciplinary Chemistry
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In synthetic allosteric systems there are typically two or more conformers with stability differences due to strain contributions. Positive cooperativity for example results from increased binding of a substrate A to a conformer C2 which is produced by binding of an effector molecule E. If the conformer C2 has a similar stability as another equilibrating conformer C1 a fit induced by the substrate A will lead to binding of A to C2 also in absence of the effector E. Only if the stability of the conformer C2 is significantly smaller, meaning that in absence of an effector E the population of C2 is much smaller than that of C1, the ratio K2/K1 which measures the efficiency of the allosteric signal will increase. The ratio K2/K1 can be related directly to the strain energy difference between the conformers C1 and C2; if it is small higher concentrations of A will directly bind to C2 and make the effector E inefficient. In addition, the response time of such allosteric switches depends on the strain of the conformer interconversion transitions state.
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Theoretical and Fundamental Chemistry
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Thiourea per se has few applications. It is mainly consumed as a precursor to thiourea dioxide, which is a common reducing agent in textile processing.
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Theoretical and Fundamental Chemistry
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The perovskite structure, ABO, is the most widespread ternary phase. The perovskite structure is frequently found for ternary oxides formed with one large (A) and one small cation (B). In this structure, there is a simple cubic array of B cations, with the A cations occupying the center of the cube, and the oxide atoms are sited at the center of the 12 edges of the simple cube.
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Theoretical and Fundamental Chemistry
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The discovery of isofagomine and related glycosidase inhibitors, the discovery of stereoelectronic substituent effects and superarmed glycosyl donors, the creation of artificial enzymes that cause large rate increases., and writing the book "Carbohydrate Building Blocks" about using carbohydrates as a chirality source in synthesis.
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Theoretical and Fundamental Chemistry
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Coal pollution mitigation, sometimes labeled as clean coal, is a series of systems and technologies that seek to mitigate health and environmental impact of burning coal for energy. Burning coal releases harmful substances, including mercury, lead, sulfur dioxide (SO2), nitrogen oxides (NOx), and carbon dioxide (CO2), contributing to air pollution, acid rain, and greenhouse gas emissions. Methods include flue-gas desulfurization, selective catalytic reduction, electrostatic precipitators, and fly ash reduction focusing on reducing the emissions of these harmful substances. These measures aim to reduce coal's impact on human health and the environment.
| 1 |
Applied and Interdisciplinary Chemistry
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Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Chemically, the precious metals tend to be less reactive than most elements. They include gold and silver, but also the so-called platinum group metals: ruthenium, rhodium, palladium, osmium, iridium, and platinum (see precious metals). Extraction of these metals from their corresponding hosting minerals would typically require pyrometallurgy (e.g., roasting), hydrometallurgy (cyanidation), or both as processing routes.
Early studies have demonstrated that gold dissolution rate in Ethaline compares very favourably to the cyanidation method, which is further enhanced by the addition of iodine as an oxidising agent. In an industrial process the iodine has the potential to be employed as an electrocatalyst, whereby it is continuously recovered in situ from the reduced iodide by electrochemical oxidation at the anode of an electrochemical cell. Dissolved metals can be selectively deposited at the cathode by adjusting the electrode potential. The method also allows better selectivity as part of the gangue (e.g., pyrite) tend to be dissolved more slowly.
Sperrylite (PtAs) and moncheite (PtTe), which are typically the more abundant platinum minerals in many orthomagmatic deposits, do not react under the same conditions in Ethaline because they are disulphide (pyrite), diarsenide (sperrylite) or ditellurides (calaverite and moncheite) minerals, which are particularly resistant to iodine oxidation. The reaction mechanism by which dissolution of platinum minerals is taking place is still under investigation.
| 1 |
Applied and Interdisciplinary Chemistry
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* History of organic chemistry
* IUPAC nomenclature of organic chemistry
* Organic reaction
* Organic compound
* Organic synthesis
** Retrosynthetic analysis
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Theoretical and Fundamental Chemistry
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Ion-exchange chromatography (IEC) or ion chromatography (IC) is an analytical technique for the separation and determination of ionic solutes in aqueous samples from environmental and industrial origins such as metal industry, industrial waste water, in biological systems, pharmaceutical samples, food, etc. Retention is based on the attraction between solute ions and charged sites bound to the stationary phase. Solute ions charged the same as the ions on the column are repulsed and elute without retention, while solute ions charged oppositely to the charged sites of the column are retained on it. Solute ions that are retained on the column can be eluted from it by changing the mobile phase composition, such as increasing its salt concentration and pH or increasing the column temperature, etc.
Types of ion exchangers include polystyrene resins, cellulose and dextran ion exchangers (gels), and controlled-pore glass or porous silica gel. Polystyrene resins allow cross linkage, which increases the stability of the chain. Higher cross linkage reduces swerving, which increases the equilibration time and ultimately improves selectivity. Cellulose and dextran ion exchangers possess larger pore sizes and low charge densities making them suitable for protein separation.
In general, ion exchangers favor the binding of ions of higher charge and smaller radius.
An increase in counter ion (with respect to the functional groups in resins) concentration reduces the retention time, as it creates a strong competition with the solute ions. A decrease in pH reduces the retention time in cation exchange while an increase in pH reduces the retention time in anion exchange. By lowering the pH of the solvent in a cation exchange column, for instance, more hydrogen ions are available to compete for positions on the anionic stationary phase, thereby eluting weakly bound cations.
This form of chromatography is widely used in the following applications: water purification, preconcentration of trace components, ligand-exchange chromatography, ion-exchange chromatography of proteins, high-pH anion-exchange chromatography of carbohydrates and oligosaccharides, and others.
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Theoretical and Fundamental Chemistry
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Oceans take up 15 – 40% of anthropogenic CO, and so far roughly 40% of the carbon from fossil fuel combustion has been taken up into the oceans. Because the Revelle factor increases with increasing CO, a smaller fraction of the anthropogenic flux will be taken up by the ocean in the future. Current annual increase in atmospheric CO is approximately 4 gigatons of carbon. This induces climate change that drives carbon concentration and carbon-climate feedback processes that modifies ocean circulation and the physical and chemical properties of seawater, which alters CO uptake. Overfishing and the plastic pollution of the oceans contribute to the degraded state of the world's biggest carbon sink.
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Theoretical and Fundamental Chemistry
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The situation becomes more complex when the form of energy does not remain constant. In this context Ohta formulated the question of energy quality in terms of the conversion of energy of one form into another, that is the transformation of energy. Here, energy quality is defined by the relative ease with which the energy transforms, from form to form.
Nomenclature: Prior to Ohtas definition above, A. W. Culp produced an energy conversion table describing the different conversions from one energy to another. Culps treatment made use of a subscript to indicate which energy form is being talked about. Therefore, instead of writing "energy A", like Ohta above, Culp referred to "J", to specify electrical form of energy, where "J" refers to "energy", and the "e" subscript refers to electrical form of energy. Culps notation anticipated Sciencemans (1997) later maxim that all energy should be specified as form energy with the appropriate subscript.
| 0 |
Theoretical and Fundamental Chemistry
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Bacterial bioluminescence is seen in Photobacterium species, Vibrio fischeri, Vibrio haweyi, and Vibrio harveyi. Light emission in some bioluminescent bacteria utilizes antenna such as lumazine protein to accept the energy from the primary excited state on the luciferase, resulting in an excited lulnazine chromophore which emits light that is of a shorter wavelength (more blue), while in others use a yellow fluorescent protein (YFP) with flavin mononucleotide (FMN) as the chromophore and emits light that is red-shifted relative to that from luciferase.
| 1 |
Applied and Interdisciplinary Chemistry
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In the narrowest sense, a nocebo response occurs when a drug-trial subjects symptoms are worsened by the administration of an inert, sham, or dummy (simulator) treatment, called a placebo. According to current pharmacological knowledge and the current understanding of cause and effect, a placebo contains no chemical (or any other agent) that could possibly cause any of the observed worsening in the subjects symptoms. Thus, any change for the worse must be due to some subjective factor. Adverse expectations can also cause the analgesic effects of anesthetic medications to disappear.
The worsening of the subjects symptoms or reduction of beneficial effects is a direct consequence of their exposure to the placebo, but those symptoms have not been chemically generated by the placebo. Because this generation of symptoms entails a complex of "subject-internal" activities, in the strictest sense, we can never speak in terms of simulator-centered "nocebo effects", but only in terms of subject-centered "nocebo responses". Although some observers attribute nocebo responses (or placebo responses) to a subjects gullibility, there is no evidence that an individual who manifests a nocebo/placebo response to one treatment will manifest a nocebo/placebo response to any other treatment; i.e., there is no fixed nocebo/placebo-responding trait or propensity.
McGlashan, Evans & Orne found no evidence in 1969 of what they termed a placebo personality. Also, in a carefully designed study, Lasagna, Mosteller, von Felsinger and Beecher in 1954, found that there was no way that any observer could determine, by testing or by interview, which subject would manifest a placebo reaction and which would not. Experiments have shown that no relationship exists between an individual's measured hypnotic susceptibility and their manifestation of nocebo or placebo responses.
Based on a biosemiotic model (2022), Goli explains how harm and/or healing expectations lead to a multimodal image and form transient allostatic or homeostatic interoceptive feelings, demonstrating how repetitive experiences of a potential body induce epigenetic changes and form new attractors, such as nocebos and placeboes, in the actual body.
| 1 |
Applied and Interdisciplinary Chemistry
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Numerous challenges limit the use of natural products for drug discovery, resulting in 21st century preference by pharmaceutical companies to dedicate discovery efforts toward high-throughput screening of pure synthetic compounds with shorter timelines to refinement. Natural product sources are often unreliable to access and supply, have a high probability of duplication, inherently create intellectual property concerns about patent protection, vary in composition due to sourcing season or environment, and are susceptible to rising extinction rates.
The biological resource for drug discovery from natural products remains abundant, with small percentages of microorganisms, plant species, and insects assessed for bioactivity. In enormous numbers, bacteria and marine microorganisms remain unexamined. As of 2008, the field of metagenomics was proposed to examine genes and their function in soil microbes, but most pharmaceutical firms have not exploited this resource fully, choosing instead to develop "diversity-oriented synthesis" from libraries of known drugs or natural sources for lead compounds with higher potential for bioactivity.
| 1 |
Applied and Interdisciplinary Chemistry
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Nitrates are used as oxidizing agents, most notably in explosives, where the rapid oxidation of carbon compounds liberates large volumes of gases (see gunpowder for an example).
| 0 |
Theoretical and Fundamental Chemistry
|
In a conventional n-type DSSC, sunlight enters the cell through the transparent SnO:F top contact, striking the dye on the surface of the TiO. Photons striking the dye with enough energy to be absorbed create an excited state of the dye, from which an electron can be "injected" directly into the conduction band of the TiO. From there it moves by diffusion (as a result of an electron concentration gradient) to the clear anode on top.
Meanwhile, the dye molecule has lost an electron and the molecule will decompose if another electron is not provided. The dye strips one from iodide in electrolyte below the TiO, oxidizing it into triiodide. This reaction occurs quite quickly compared to the time that it takes for the injected electron to recombine with the oxidized dye molecule, preventing this recombination reaction that would effectively short-circuit the solar cell.
The triiodide then recovers its missing electron by mechanically diffusing to the bottom of the cell, where the counter electrode re-introduces the electrons after flowing through the external circuit.
| 0 |
Theoretical and Fundamental Chemistry
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Thallium-doped sodium iodide (NaI(Tl)) has two principal advantages:
# It can be produced in large crystals, yielding good efficiency, and
# it produces intense bursts of light compared to other spectroscopic scintillators.
NaI(Tl) is also convenient to use, making it popular for field applications such as the identification of unknown materials for law enforcement purposes.
Electron hole recombination will emit light that can re-excite pure scintillation crystals; however, the thallium dopant in NaI(Tl) provides energy states within the band gap between the conduction and valence bands. Following excitation in doped scintillation crystals, some electrons in the conduction band will migrate to the activator states; the downward transitions from the activator states will not re-excite the doped crystal, so the crystal is transparent to this radiation.
An example of a NaI spectrum is the gamma spectrum of the caesium isotope —see Figure 1. emits a single gamma line of 662 keV. The 662 keV line shown is actually produced by , the decay product of , which is in secular equilibrium with .
The spectrum in Figure 1 was measured using a NaI-crystal on a photomultiplier, an amplifier, and a multichannel analyzer. The figure shows the number of counts within the measuring period versus channel number. The spectrum indicates the following peaks (from left to right):
# low energy x radiation (due to internal conversion of the gamma ray),
# backscatter at the low energy end of the Compton distribution, and
# a photopeak (full energy peak) at an energy of 662 keV
The Compton distribution is a continuous distribution that is present up to channel 150 in Figure 1. The distribution arises because of primary gamma rays undergoing Compton scattering within the crystal: Depending on the scattering angle, the Compton electrons have different energies and hence produce pulses in different energy channels.
If many gamma rays are present in a spectrum, Compton distributions can present analysis challenges. To reduce gamma rays, an anticoincidence shield can be used—see Compton suppression. Gamma ray reduction techniques are especially useful for small lithium-doped germanium (Ge(Li)) detectors.
The gamma spectrum shown in Figure 2 is of the cobalt isotope , with two gamma rays with 1.17 MeV and 1.33 MeV respectively. (See the decay scheme article for the decay scheme of cobalt-60.) The two gamma lines can be seen well-separated; the peak to the left of channel 200 most likely indicates a strong background radiation source that has not been subtracted. A backscatter peak can be seen near channel 150, similar to the second peak in Figure 1.
Sodium iodide systems, as with all scintillator systems, are sensitive to changes in temperature. Changes in the operating temperature caused by changes in environmental temperature will shift the spectrum on the horizontal axis. Peak shifts of tens of channels or more are commonly observed. Such shifts can be prevented by using spectrum stabilizers.
Because of the poor resolution of NaI-based detectors, they are not suitable for the identification of complicated mixtures of gamma ray-producing materials. Scenarios requiring such analyses require detectors with higher resolution.
| 0 |
Theoretical and Fundamental Chemistry
|
Eukaryotic Rad51 and its related family members are homologous to the archaeal RadA and bacterial RecA recombinases. Rad51 is highly conserved from yeast to humans. It has a key function in the recombinational repair of DNA damages, particularly double-strand damages such as double-strand breaks. In humans, over- or under-expression of Rad51 occurs in a wide variety of cancers.
During meiosis Rad51 interacts with another recombinase, Dmc1, to form a presynaptic filament that is an intermediate in homologous recombination. Dmc1 function appears to be limited to meiotic recombination. Like Rad51, Dmc1 is homologous to bacterial RecA.
| 1 |
Applied and Interdisciplinary Chemistry
|
While at PAEC, Qureshi joined the chemistry department of Quaid-e-Azam University as an associate professor. In the 1990s, he joined the Punjab University to teach post-graduate course on physical chemistry. In the 2000s, he joined the Lahore University of Management Sciences's School of Science and Engineering as director of engineering and safety.
Over the years, he became known for his strong scientific advocacy of peaceful usage of nuclear energy, safety, and security, following the Fukushima disaster. A member of Khwarizmi Science Society, he has lectured on safety issues regarded the nuclear power and topics in nuclear chemistry. He has also authored numerous articles on chemical safety and securities around the world in worlds leading research journal. In 2011, he lectured on physical chemistry and spoke about how nuclear technology was being used currently and different ways of disposing nuclear waste at the Forman Christian College University in Lahore. He is the recipient of Pakistans highest honours– the Hilal-i-Imtiaz bestowed in 2003 and the Sitara-e-Imtiaz bestowed in 1999 by the Government of Pakistan.
| 0 |
Theoretical and Fundamental Chemistry
|
Applications of phase change materials include, but are not limited to:
* Thermal energy storage, such as the FlexTherm Eco by Flamco.
* Solar cooking
* Cold Energy Battery
* Conditioning of buildings, such as ice-storage
* Cooling of heat and electrical engines
* Cooling: food, beverages, coffee, wine, milk products, green houses
*Delaying ice and frost formation on surfaces
* Medical applications: transportation of blood, operating tables, hot-cold therapies, treatment of birth asphyxia
* Human body cooling under bulky clothing or costumes.
* Waste heat recovery
* Off-peak power utilization: Heating hot water and Cooling
* Heat pump systems
* Passive storage in bioclimatic building/architecture (HDPE, paraffin)
* Smoothing exothermic temperature peaks in chemical reactions
* Solar power plants
* Spacecraft thermal systems
* Thermal comfort in vehicles
* Thermal protection of electronic devices
* Thermal protection of food: transport, hotel trade, ice-cream, etc.
* Textiles used in clothing
* Computer cooling
* Turbine Inlet Chilling with thermal energy storage
* Telecom shelters in tropical regions. They protect the high-value equipment in the shelter by keeping the indoor air temperature below the maximum permissible by absorbing heat generated by power-hungry equipment such as a Base Station Subsystem. In case of a power failure to conventional cooling systems, PCMs minimize use of diesel generators, and this can translate into enormous savings across thousands of telecom sites in tropics.
| 0 |
Theoretical and Fundamental Chemistry
|
Two dimensional space has the same number of crystal systems, crystal families, and lattice systems. In 2D space, there are four crystal systems: oblique, rectangular, square, and hexagonal.
| 0 |
Theoretical and Fundamental Chemistry
|
Trifluoroperacetic acid can be easily prepared by an Organic Syntheses process of treating trifluoroacetic anhydride with a concentrated (90%) aqueous solution of hydrogen peroxide:
:trifluoroacetic anhydride| + hydrogen peroxide| → + trifluoroacetic acid|
As the anhydride will form trifluoroacetic acid in contact with water, an excess of the anhydride also serves to remove the solvent from the peroxide reactant:
: + water| → 2
A more dilute hydrogen peroxide solution (30%) can be used to form trifluoroperacetic acid for some reactions from trifluoroacetic acid.
In order to avoid the danger of handling pure or highly concentrated solutions of hydrogen peroxide, hydrogen peroxide – urea can be used to give the peracid. This method involves no water, so it gives a completely anhydrous peracid, which is an advantage when the presence of water leads to side reactions during certain oxidation reactions.
: + hydrogen peroxide - urea| → + + urea|
In cases where a pH buffering agent is needed for a synthesis and where the presence of water is tolerated, another approach has been developed. Reacting trifluoroacetic anhydride with sodium percarbonate, , yields trifluoroperacetic acid and sodium carbonate, obviating the need for an additional buffer.
:3 + 4 sodium percarbonate| → 6 + 4 sodium carbonate| + 3
Trifluoroperacetic acid can also be generated in situ, allowing it to react promptly with the target substrate rather than pre-synthesizing a batch of the reagent for later use.
| 0 |
Theoretical and Fundamental Chemistry
|
*2011 – Elected Fellow, Royal Society of Canada
*2012 – Elected Fellow, Mineralogical Society of America
*2013 – Island Arc Award, the Geological Society of Japan
*2022 – Takeo Kato Gold Medal, the Society of Resource Geology
*2022 – International Exchange Lecturer, Society of Economic Geologists
*2023 – Distinguished University Professor, University of Ottawa
| 0 |
Theoretical and Fundamental Chemistry
|
Many alloys of elements that resemble each other chemically will form a structure at higher temperatures where the two elements occupy similar positions in the lattice at random. At lower temperatures ordering may occur where crystallographic positions are no longer equivalent because one element preferentially occupies one site and the other the other. This partial ordering process may lower the translation symmetry and result in a different, larger unit cell.
| 0 |
Theoretical and Fundamental Chemistry
|
Gravimetric analysis usually only provides for the analysis of a single element, or a limited group of elements, at a time. Comparing modern dynamic flash combustion coupled with gas chromatography with traditional combustion analysis will show that the former is both faster and allows for simultaneous determination of multiple elements while traditional determination allowed only for the determination of carbon and hydrogen. Methods are often convoluted and a slight mis-step in a procedure can often mean disaster for the analysis (colloid formation in precipitation gravimetry, for example). Compare this with hardy methods such as spectrophotometry and one will find that analysis by these methods is much more efficient.
| 0 |
Theoretical and Fundamental Chemistry
|
Oxidation state localized orbitals (OSLOs) is a new concept used to determine the oxidation states of each fragment for the coordination complexes. Based on the result of density functional theory (DFT), all the occupied molecular orbitals are remixed to get the oxidation state localized orbitals. These orbitals are assigned to one of the fragments in this molecule based on the fragment orbital localization index (FOLI). After all the electrons are assigned, the oxidation states of each fragment could be obtained by calculating the difference between the number of electrons and protons in each fragment.
| 0 |
Theoretical and Fundamental Chemistry
|
These are the second stage product of protein hydrolysis obtained by treatment with slightly stronger acids and alkalies.
| 1 |
Applied and Interdisciplinary Chemistry
|
It is known that aluminum improves the sulfidation resistance of iron alloys.
The sulfidation of tungsten is a multiple step process. The first step is an oxidation reaction, converting the tungsten to a tungsten bronze on the surface of the object. The tungsten bronze coating is then converted to a sulfide.
One commonly encountered occurrence of sulfidation in manufacturing environments involves the sulfidic corrosion of metal piping. The increased resistance to corrosion found in stainless steel is attributed to a layer of chromium oxide that forms due to oxidation of the chromium found in the alloy.
The process of liquid sulfidation has also been used in the manufacturing of diamond-like carbon films. These films are generally used to coat surfaces to reduce the wear due to friction. The inclusion of sulfidation in the process has been shown to reduce the friction coefficient of the diamond-like carbon film.
| 0 |
Theoretical and Fundamental Chemistry
|
The U.S. Institute of Medicine (IOM) established Recommended Dietary Allowances (RDAs) for calcium in 1997 and updated those values in 2011. See table. The
European Food Safety Authority (EFSA) uses the term Population Reference Intake (PRIs) instead of RDAs and sets slightly different numbers: ages 4–10 800 mg, ages 11–17 1150 mg, ages 18–24 1000 mg, and >25 years 950 mg.
Because of concerns of long-term adverse side effects such as calcification of arteries and kidney stones, the IOM and EFSA both set Tolerable Upper Intake Levels (ULs) for the combination of dietary and supplemental calcium. From the IOM, people ages 9–18 years are not supposed to exceed 3,000 mg/day; for ages 19–50 not to exceed 2,500 mg/day; for ages 51 and older, not to exceed 2,000 mg/day. The EFSA set UL at 2,500 mg/day for adults but decided the information for children and adolescents was not sufficient to determine ULs.
| 1 |
Applied and Interdisciplinary Chemistry
|
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2021 impact factor of 12.388.
| 1 |
Applied and Interdisciplinary Chemistry
|
TFB is recruited by another translation factor, TBP, after it recognizes the TATA box and bends the DNA so transcription can initiate. TFB stabilizes the TBP-DNA complex so that the proteins can recruit RNA Polymerase and melt the DNA via a yet-unknown mechanism. This opening of the DNA is not an energy-dependent process in Archaea; since TFB, TBP, and RNAP are located more closely to each other than in Eukarya, the tightness of the proteins and their interactions may provide more areas of contact to open the DNA as well as physically strain the DNA, which leads to an open transcription complex.
TFB uses a zinc ion (Zn) as a cofactor and accepts one ion per subunit.
| 1 |
Applied and Interdisciplinary Chemistry
|
Resource productivity is the quantity of good or service (outcome) that is obtained through the expenditure of unit resource. This can be expressed in monetary terms as the monetary yield per unit resource.
For example, when applied to crop irrigation it is the yield of crop obtained through use of a given volume of irrigation water, the “crop per drop”, which could also be expressed as monetary return from product per use of unit irrigation water.
Resource productivity and resource intensity are key concepts used in sustainability measurement as they attempt to decouple the direct connection between resource use and environmental degradation. Their strength is that they can be used as a metric for both economic and environmental cost. Although these concepts are two sides of the same coin, in practice they involve very different approaches and can be viewed as reflecting, on the one hand, the efficiency of resource production as outcome per unit of resource use (resource productivity) and, on the other hand, the efficiency of resource consumption as resource use per unit outcome (resource intensity). The sustainability objective is to maximize resource productivity while minimizing resource intensity. Scientific and political debates on resource productivity are regularly held at, among others, the World Resources Forum conferences.
| 0 |
Theoretical and Fundamental Chemistry
|
Matter is classified as solid, liquid, gaseous, energy, fine Karmic materials and extra-fine matter i.e. ultimate particles. Paramāṇu or ultimate particle (atoms or sub-atomic particles) is the basic building block of all matter. It possesses at all times four qualities, namely, a color (varna), a taste (rasa), a smell (gandha), and a certain kind of palpability (sparsha, touch). One of the qualities of the paramāṇu and pudgala is that of permanence and indestructibility. It combines and changes its modes but its basic qualities remain the same. It cannot be created nor destroyed and the total amount of matter in the universe remains the same.
| 1 |
Applied and Interdisciplinary Chemistry
|
The optical band gap (see below) determines what portion of the solar spectrum a photovoltaic cell absorbs. Strictly, a semiconductor will not absorb photons of energy less than the band gap; whereas most of the photons with energies exceeding the band gap will generate heat. Neither of them contribute to the efficiency of a solar cell. One way to circumvent this problem is based on the so-called photon management concept, in which case the solar spectrum is modified to match the absorption profile of the solar cell.
| 0 |
Theoretical and Fundamental Chemistry
|
Bimolecular nucleophilic substitution (SN2) reactions are concerted reactions where both the nucleophile and substrate are involved in the rate limiting step. Since this reaction is concerted, the reaction occurs in one step, where the bonds are broken, while new bonds are formed. Therefore, to interpret this reaction, it is important to look at the transition state, which resembles the concerted rate limiting step. In the "Depiction of S2 Reaction" figure, the nucleophile forms a new bond to the carbon, while the halide (L) bond is broken.
| 0 |
Theoretical and Fundamental Chemistry
|
Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers that are generally of defined size and they are flanked on both sides by conserved regions to ensure their reliability. While indels can be arbitrary inserts or deletions, CSIs are defined as only those protein indels that are present within conserved regions of the protein.
The CSIs that are restricted to a particular clade or group of species, generally provide good phylogenetic markers of common evolutionary descent. Due to the rarity and highly specific nature of such changes, it is less likely that they could arise independently by either convergent or parallel evolution (i.e. homoplasy) and therefore are likely to represent synapomorphy. Other confounding factors such as differences in evolutionary rates at different sites or among different species also generally do not affect the interpretation of a CSI. By determining the presence or absence of CSIs in an out-group species, one can infer whether the ancestral form of the CSI was an insert or deletion and this can be used to develop a rooted phylogenetic relationship among organisms.
CSIs are discovered by looking for shared changes in a phylogenetic tree constructed from protein sequences. Most CSIs that have been identified have been found to have high predictive value upon addition of new sequences, retaining the specificity for the originally identified clades of species. They can be used to identify both known and even previously unknown species belonging to these groups in different environments. Compared to tree branching orders which can vary among methods, specific CSIs make for more concrete circumscriptions that are computationally cheaper to apply.
| 1 |
Applied and Interdisciplinary Chemistry
|
In December 2021, the FDA came up with a draft guidance for the use of ASO drug products. This draft guidance was directed towards sponsor-investigators who are developing individualized investigational antisense oligonucleotides (ASO) drug products for severely debilitating or life threatening diseases. Severely debilitating corresponds to a disease or condition that causes major irreversible morbidity. However, life-threatening is defined as the disease or condition has a likelihood of death unless the course of treatment leads to an endpoint of survival. Usually individuals that have a severely debilitating life threatening disease don't have any alternative treatment options, and their diseases will be rapidly progressing, leading to an early death and/or devastating or irreversible morbidity within a short time frame without treatment.
Drug development is usually targeted for a large number of individuals, in this case that is not possible because of the specificity of the mechanism of action of the ASO combined with the rarity of the treatment-amenable patient population. Under FDA regulations, a protocol under which an individual ASO product is administered to a human subject must be reviewed and approved by an institutional review board (IRB) before it can be administered to human subjects. When the individual is a child, additional safeguards need to be identified in order to prevent any developmental issues from occurring that may affect the life of the individual. The sponsor-investigator needs to get informed consent from the individual or from the person who is responsible for the individual. The consent needs to include a description of reasonably foreseeable risks or discomforts as part of the use of the ASO drug. The sponsor also needs to get individuals clinical and genetic diagnosis to confirm that the ASO will be beneficial. The analysis may be through gene sequencing, enzymatic analysis, biochemical testing, imaging evaluations. All results need to be included in the application. Also the sponsor needs to include evidence that establishes the role of the gene variant targeted by the ASO drug. The sponsor/investigator need to also provide evidence that the identified gene variant or variants are unique to the individual.
The guidance suggests that the starting dose should be based on available non-clinical data that has been collected from model organisms or in vitro studies and should be in correlation with other ASO drug product dosing information that is available. At the starting dose, pharmacological effects are expected. Furthermore, It is advised that a dosing escalation method be utilized. This includes the step of escalating the dodge from its initial dose based on pharmacodynamic effects and/or trial participants' response to the ASO.
In addition, protocols submitted to the FDA need to have a clear dosing plan and justification for selecting the starting dose, dosing interval, and plan for dose escalation or dose reduction based on clinical pharmacodynamic effects of the drug on the individual. Also all anticipated outcomes should be included in the drug plan when submitted to the FDA. It is extremely important for the investigators to monitor the patient closely during dose escalation. During the escalation period, adequate time should be provided in order to see therapeutic results. It is advised that the investigator not make concurrent changes to the dosing interval along with the dose without justification. The submitted plan should include a de-escalation/discontinuation plan if toxicity is observed. All drug administration needs to take place in an inpatient setting just to get a grasp of the adverse effects the drug may have. Once drug toxicity, beneficiancy and adverse effects are identified, the drug can be administered in an outpatient manner as long as the same concentration of drug is administered.
| 1 |
Applied and Interdisciplinary Chemistry
|
To measure the IMFP, one well known method is elastic-peak electron spectroscopy (EPES). This method measures the intensity of elastically backscattered electrons with a certain energy from a sample material in a certain direction. Applying a similar technique to materials whose IMFP is known, the measurements are compared with the results from the Monte Carlo simulations under the same conditions. Thus, one obtains the IMFP of a certain material in a certain energy spectrum. EPES measurements show a root-mean-square (RMS) difference between 12% and 17% from the theoretical expected values. Calculated and experimental results show higher agreement for higher energies.
For electron energies in the range 30 keV – 1 MeV, IMFP can be directly measured by electron energy loss spectroscopy inside a transmission electron microscope, provided the sample thickness is known. Such measurements reveal that IMFP in elemental solids is not a smooth, but an oscillatory function of the atomic number.
For energies below 100 eV, IMFP can be evaluated in high-energy secondary electron yield (SEY) experiments. Therefore, the SEY for an arbitrary incident energy between 0.1 keV-10 keV is analyzed. According to these experiments, a Monte Carlo model can be used to simulate the SEYs and determine the IMFP below 100 eV.
| 0 |
Theoretical and Fundamental Chemistry
|
Sensor-based sorting installations normally comprise the following basic units; crusher, screen, sensor-based sorter and compressor. There are principally two different kinds of installations that are described in the following paragraphs – stationary and semi-mobile installations.
| 0 |
Theoretical and Fundamental Chemistry
|
The Radium Dial Company was started in 1917 and was in full production of painted dials by 1918. The company was a division of the Standard Chemical Company based in the Marshall Field Annex building in Chicago. In 1920 the company relocated to Peru, Illinois to closer proximity to the clock manufacturer and major customer, Westclox.
By 1922 the company had moved to a former high school building at 1022 Columbus Street in Ottawa, Illinois where it remained until the mid-1930s. At the highest point in production (around 1925), the Radium Dial Company employed around 1,000 young women who turned out around 4,300 dials each day.
The company was headed by Joseph A. Kelly Sr. Kelly opened up a new corporation called Luminous Processes Inc. a few blocks away from the Radium Dial Company in Ottawa, Illinois shortly after closing down the Radium Dial Company. Luminous Processes Inc. continued producing fluorescent watch dials powered by radium radioactivity until 1978.
| 0 |
Theoretical and Fundamental Chemistry
|
Overhead power lines transfer electrical energy from electricity producers to consumers. Those power lines have a nonzero resistance and therefore are subject to Joule heating, which causes transmission losses.
The split of power between transmission losses (Joule heating in transmission lines) and load (useful energy delivered to the consumer) can be approximated by a voltage divider. In order to minimize transmission losses, the resistance of the lines has to be as small as possible compared to the load (resistance of consumer appliances). Line resistance is minimized by the use of copper conductors, but the resistance and power supply specifications of consumer appliances are fixed.
Usually, a transformer is placed between the lines and consumption. When a high-voltage, low-intensity current in the primary circuit (before the transformer) is converted into a low-voltage, high-intensity current in the secondary circuit (after the transformer), the equivalent resistance of the secondary circuit becomes higher and transmission losses are reduced in proportion.
During the war of currents, AC installations could use transformers to reduce line losses by Joule heating, at the cost of higher voltage in the transmission lines, compared to DC installations.
| 0 |
Theoretical and Fundamental Chemistry
|
By multiplying the top and bottom of the Shields parameter by D, you can see that it is proportional to the ratio of fluid force on the particle to the weight of the particle.
| 1 |
Applied and Interdisciplinary Chemistry
|
In pulse arterial spin labeling (PASL), blood water is inverted as it passes through a labeling slab (of 15 to 20 cm) instead of a plane. There are different variations of this implementations, including EPISTAR and PICORE and PULSAR. Most scanners have been designed to have PASL work out-of-the-box for research use.
| 0 |
Theoretical and Fundamental Chemistry
|
Miyata's distance is based on 2 physicochemical properties: volume and polarity.
Distance between amino acids a and a is calculated as where is value of polarity difference between replaced amino acids and and is difference for volume; and are standard deviations for and
| 1 |
Applied and Interdisciplinary Chemistry
|
The asialoglycoprotein receptors (ASGPR) are lectins which bind asialoglycoprotein and glycoproteins from which a sialic acid has been removed to expose galactose residues. The receptors, which are integral membrane proteins and are located on mammalian hepatocytes (liver cells), remove target glycoproteins from circulation. The asialoglycoprotein receptor has been demonstrated to have high expression on the surface of hepatocytes and several human carcinoma cell lines It is also weakly expressed by glandular cells of the gallbladder and the stomach. Lactobionic acid has been used as a targeting moiety for drug delivery to cells expressing asialoglycoprotein receptors.
The asialoglycoprotein receptor contains two subunits, asialoglycoprotein receptor 1 (ASGR1) and asialoglycoprotein receptor 2 (ASGR2). These subunits may form different quaternary forms such as dimers, trimers, tetramers to allow for specific substrate binding or endocytosis. ASGR 1 is the major subunit and has 8 exons and is roughly 6 kb in length. ASGR 2 is the minor subunit and has 9 exons and is about 13.5 kb long.
| 1 |
Applied and Interdisciplinary Chemistry
|
Vigilant caution should be taken while using TRIzol (due to the phenol and chloroform).
TRIzol is labeled as acute oral, dermal, and inhalation toxicity besides skin corrosion/irritation in the manufacturer MDS.
Exposure to TRIzol can be a serious health hazard. Exposure can lead to serious chemical burns, permanent scarring and kidney failure.
Experiments should be performed under a chemical hood, with lab coat, nitrile gloves and a plastic apron.
TRIzol waste should never be mixed with bleach or acids: the guanidinium thiocyanate in TRIzol reacts to form highly toxic gases.
| 1 |
Applied and Interdisciplinary Chemistry
|
Chemurgy demonstrated its worth during World War II, particularly in alleviating the rubber shortage caused when Japan cut off most of America's supply. Corn was used as raw material in much of the synthetic rubber produced during the war. Various other plants, including guayule and kok-saghyz (Russian dandelion), were investigated as rubber sources. In the American Midwest, school children were encouraged to gather milkweed floss, previously considered a nuisance but now valued for a new role as a filler in military life jackets. A priest in Iowa even made news by urging congregants to grow hemp, whose previous reputation as a drug hazard yielded to military requirements for rope and cordage.
| 1 |
Applied and Interdisciplinary Chemistry
|
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