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Dendrimer	Applications	Role of dendrimer chemical modifications in drug delivery Dendrimers are particularly versatile drug delivery devices due to the wide range of chemical modifications that can be made to increase in vivo suitability and allow for site-specific targeted drug delivery.
Dendrimer	Applications	Drug attachment to the dendrimer may be accomplished by (1) a covalent attachment or conjugation to the external surface of the dendrimer forming a dendrimer prodrug, (2) ionic coordination to charged outer functional groups, or (3) micelle-like encapsulation of a drug via a dendrimer-drug supramolecular assembly. In the case of a dendrimer prodrug structure, linking of a drug to a dendrimer may be direct or linker-mediated depending on desired release kinetics. Such a linker may be pH-sensitive, enzyme catalyzed, or a disulfide bridge. The wide range of terminal functional groups available for dendrimers allows for many different types of linker chemistries, providing yet another tunable component on the system. Key parameters to consider for linker chemistry are (1) release mechanism upon arrival to the target site, whether that be within the cell or in a certain organ system, (2) drug-dendrimer spacing so as to prevent lipophilic drugs from folding into the dendrimer, and (3) linker degradability and post-release trace modifications on drugs.Polyethylene glycol (PEG) is a common modification for dendrimers to modify their surface charge and circulation time. Surface charge can influence the interactions of dendrimers with biological systems, such as amine-terminal modified dendrimers which have a propensity to interact with cell membranes with anionic charge. Certain in vivo studies have shown polycationic dendrimers to be cytotoxic through membrane permeabilization, a phenomenon that could be partially mitigated via addition of PEGylation caps on amine groups, resulting in lower cytotoxicity and lower red blood cell hemolysis. Additionally, studies have found that PEGylation of dendrimers results in higher drug loading, slower drug release, longer circulation times in vivo, and lower toxicity in comparison to counterparts without PEG modifications.Numerous targeting moieties have been used to modify dendrimer biodistribution and allow for targeting to specific organs. For example, folate receptors are overexpressed in tumor cells and are therefore promising targets for localized drug delivery of chemotherapeutics. Folic acid conjugation to PAMAM dendrimers has been shown to increase targeting and decrease off-target toxicity while maintaining on-target cytotoxicity of chemotherapeutics such as methotrexate, in mouse models of cancer.Antibody-mediated targeting of dendrimers to cell targets has also shown promise for targeted drug delivery. As epidermal growth factor receptors (EGFRs) are often overexpressed in brain tumors, EGFRs are a convenient target for site-specific drug delivery. The delivery of boron to cancerous cells is important for effective neutron capture therapy, a cancer treatment which requires a large concentration of boron in cancerous cells and a low concentration in healthy cells. A boronated dendrimer conjugated with a monoclonal antibody drug that targets EGFRs was used in rats to successfully deliver boron to cancerous cells.Modifying nanoparticle dendrimers with peptides has also been successful for targeted destruction of colorectal (HCT-116) cancer cells in a co-culture scenario. Targeting peptides can be used to achieve site- or cell-specific delivery, and it has been shown that these peptides increase in targeting specificity when paired with dendrimers. Specifically, gemcitabine-loaded YIGSR-CMCht/PAMAM, a unique kind of dendrimer nanoparticle, induces a targeted mortality on these cancer cells. This is performed via selective interaction of the dendrimer with laminin receptors. Peptide dendrimers may be employed in the future to precisely target cancer cells and deliver chemotherapeutic agents.The cellular uptake mechanism of dendrimers can also be tuned using chemical targeting modifications. Non-modified PAMAM-G4 dendrimer is taken up into activated microglia by fluid phase endocytosis. Conversely, mannose modification of hydroxyl PAMAM-G4 dendrimers was able to change the mechanism of internalization to mannose-receptor (CD206) mediated endocytosis. Additionally, mannose modification was able to change the biodistribution in the rest of the body in rabbits.
Dendrimer	Applications	Pharmacokinetics and pharmacodynamics Dendrimers have the potential to completely change the pharmacokinetic and pharmacodynamic (PK/PD) profiles of a drug. As carriers, the PK/PD is no longer determined by the drug itself but by the dendrimer’s localization, drug release, and dendrimer excretion. ADME properties are very highly tunable by varying dendrimer size, structure, and surface characteristics. While G9 dendrimers biodistribute very heavily to the liver and spleen, G6 dendrimers tend to biodistribute more broadly. As molecular weight increases, urinary clearance and plasma clearance decrease while terminal half-life increases.
Dendrimer	Applications	Routes of delivery To increase patient compliance with prescribed treatment, delivery of drugs orally is often preferred to other routes of drug administration. However oral bioavailability of many drugs tends to be very low. Dendrimers can be used to increase the solubility and stability of orally-administered drugs and increase drug penetration through the intestinal membrane. The bioavailability of PAMAM dendrimers conjugated to a chemotherapeutic has been studied in mice; it was found that around 9% of dendrimer administered orally was found intact in circulation and that minimal dendrimer degradation occurred in the gut.Intravenous dendrimer delivery shows promise as gene vectors to deliver genes to various organs in the body, and even tumors. One study found that through intravenous injection, a combination of PPI dendrimers and gene complexes resulted in gene expression in the liver, and another study showed that a similar injection regressed the growth of tumors in observed animals.The primary obstacle to transdermal drug delivery is the epidermis. Hydrophobic drugs have a very difficult time penetrating the skin layer, as they partition heavily into skin oils. Recently, PAMAM dendrimers have been used as delivery vehicles for NSAIDS to increase hydrophilicity, allowing greater drug penetration. These modifications act as polymeric transdermal enhancers allowing drugs to more easily penetrate the skin barrier.
Dendrimer	Applications	Dendrimers may also act as new ophthalmic vehicles for drug delivery, which are different from the polymers currently used for this purpose. A study by Vanndamme and Bobeck used PAMAM dendrimers as ophthalmic delivery vehicles in rabbits for two model drugs and measured the ocular residence time of this delivery to be comparable and in some cases greater than current bioadhesive polymers used in ocular delivery. This result indicates that administered drugs were more active and had increased bioavailability when delivered via dendrimers than their free-drug counterparts. Additionally, photo-curable, drug-eluting dendrimer-hyaluronic acid hydrogels have been used as corneal sutures applied directly to the eye. These hydrogel sutures have shown efficacy as a medical device in rabbit models that surpasses traditional sutures and minimizes corneal scarring.
Dendrimer	Applications	Brain drug delivery Dendrimer drug delivery has also shown major promise as a potential solution for many traditionally difficult drug delivery problems. In the case of drug delivery to the brain, dendrimers are able to take advantage of the EPR effect and blood-brain barrier (BBB) impairment to cross the BBB effectively in vivo. For example, hydroxyl-terminated PAMAM dendrimers possess an intrinsic targeting ability to inflamed macrophages in the brain, verified using fluorescently labeled neutral generation dendrimers in a rabbit model of cerebral palsy. This intrinsic targeting has enabled drug delivery in a variety of conditions, ranging from cerebral palsy and other neuroinflammatory disorders to traumatic brain injury and hypothermic circulatory arrest, across a variety of animal models ranging from mice and rabbits to canines. Dendrimer uptake into the brain correlates with severity of inflammation and BBB impairment and it is believed that the BBB impairment is the key driving factor allowing dendrimer penetration. Localization is heavily skewed towards activated microglia. Dendrimer-conjugated N-acetyl cysteine has shown efficacy in vivo as an anti-inflammatory at more than 1000-fold lower dose than free drug on a drug basis, reversing the phenotype of cerebral palsy, Rett syndrome, macular degeneration and other inflammatory diseases.
Dendrimer	Applications	Clinical trials Starpharma, an Australian pharmaceutical company, has multiple products that have either already been approved for use or are in the clinical trial phase. SPL7013, also known as astodrimer sodium, is a hyperbranched polymer used in Starpharma’s VivaGel line of pharmaceuticals that is currently approved to treat bacterial vaginosis and prevent the spread of HIV, HPV, and HSV in Europe, Southeast Asia, Japan, Canada, and Australia. Due to SPL7013’s broad antiviral action, it has recently been tested by the company as a potential drug to treat SARS-CoV-2. The company states preliminary in-vitro studies show high efficacy in preventing SARS-CoV-2 infection in cells.
Dendrimer	Applications	Gene delivery and transfection The ability to deliver pieces of DNA to the required parts of a cell includes many challenges. Current research is being performed to find ways to use dendrimers to traffic genes into cells without damaging or deactivating the DNA. To maintain the activity of DNA during dehydration, the dendrimer/DNA complexes were encapsulated in a water-soluble polymer, and then deposited on or sandwiched in functional polymer films with a fast degradation rate to mediate gene transfection. Based on this method, PAMAM dendrimer/DNA complexes were used to encapsulate functional biodegradable polymer films for substrate mediated gene delivery. Research has shown that the fast-degrading functional polymer has great potential for localized transfection.
Dendrimer	Applications	Sensors Dendrimers have potential applications in sensors. Studied systems include proton or pH sensors using poly(propylene imine), cadmium-sulfide/polypropylenimine tetrahexacontaamine dendrimer composites to detect fluorescence signal quenching, and poly(propylenamine) first and second generation dendrimers for metal cation photodetection amongst others. Research in this field is vast and ongoing due to the potential for multiple detection and binding sites in dendritic structures.
Dendrimer	Applications	Nanoparticles Dendrimers also are used in the synthesis of monodisperse metallic nanoparticles. Poly(amidoamide), or PAMAM, dendrimers are utilized for their tertiary amine groups at the branching points within the dendrimer. Metal ions are introduced to an aqueous dendrimer solution and the metal ions form a complex with the lone pair of electrons present at the tertiary amines. After complexation, the ions are reduced to their zerovalent states to form a nanoparticle that is encapsulated within the dendrimer. These nanoparticles range in width from 1.5 to 10 nanometers and are called dendrimer-encapsulated nanoparticles.
Dendrimer	Applications	Other applications Given the widespread use of pesticides, herbicides and insecticides in modern farming, dendrimers are also being used by companies to help improve the delivery of agrochemicals to enable healthier plant growth and to help fight plant diseases.Dendrimers are also being investigated for use as blood substitutes. Their steric bulk surrounding a heme-mimetic centre significantly slows degradation compared to free heme, and prevents the cytotoxicity exhibited by free heme.
Dendrimer	Applications	Dendritic functional polymer polyamidoamine (PAMAM) is used to prepare core shell structure i.e. microcapsules and utilized in formulation of self-healing coatings of conventional and renewable origins.
Dendrimer	Applications	Drug delivery Dendrimers in drug-delivery systems is an example of various host–guest interactions. The interaction between host and guest, the dendrimer and the drug, respectively, can either be hydrophobic or covalent. Hydrophobic interaction between host and guest is considered "encapsulated," while covalent interactions are considered to be conjugated. The use of dendrimers in medicine has shown to improve drug delivery by increasing the solubility and bioavailability of the drug. In conjunction, dendrimers can increase both cellular uptake and targeting ability, and decrease drug resistance.The solubility of various nonsteroidal anti-inflammatory drugs (NSAID) increases when they are encapsulated in PAMAM dendrimers. This study shows the enhancement of NSAID solubility is due to the electrostatic interactions between the surface amine groups in PAMAM and the carboxyl groups found in NSAIDs. Contributing to the increase in solubility are the hydrophobic interactions between the aromatic groups in the drugs and the interior cavities of the dendrimer. When a drug is encapsulated within a dendrimer, its physical and physiological properties remains unaltered, including non-specificity and toxicity. However, when the dendrimer and the drug are covalently linked together, it can be used for specific tissue targeting and controlled release rates. Covalent conjugation of multiple drugs on dendrimer surfaces can pose a problem of insolubility.This principle is also being studied for cancer treatment application. Several groups have encapsulated anti-cancer medications such as: Camptothecin, Methotrexate, and Doxorubicin. Results from these research has shown that dendrimers have increased aqueous solubility, slowed release rate, and possibly control cytotoxicity of the drugs. Cisplatin has been conjugated to PAMAM dendrimers that resulted in the same pharmacological results as listed above, but the conjugation also helped in accumulating cisplatin in solid tumors in intravenous administration.
Iron(III) fluoride	Iron(III) fluoride	Iron(III) fluoride, also known as ferric fluoride, are inorganic compounds with the formula FeF3(H2O)x where x = 0 or 3. They are mainly of interest by researchers, unlike the related iron(III) chloride. Anhydrous iron(III) fluoride is white, whereas the hydrated forms are light pink.
Iron(III) fluoride	Chemical and physical properties	Iron(III) fluoride is a thermally robust, antiferromagnetic solid consisting of high spin Fe(III) centers, which is consistent with the pale colors of all forms of this material. Both anhydrous iron(III) fluoride as well as its hydrates are hygroscopic.
Iron(III) fluoride	Structure	The anhydrous form adopts a simple structure with octahedral Fe(III)F6 centres interconnected by linear Fe-F-Fe linkages. In the language of crystallography, the crystals are classified as rhombohedral with an R-3c space group. The structural motif is similar to that seen in ReO3. Although the solid is nonvolatile, it evaporates at high temperatures, the gas at 987 °C consists of FeF3, a planar molecule of D3h symmetry with three equal Fe-F bonds, each of length 176.3 pm. At very high temperatures, it decomposes to give FeF2 and F2.Two crystalline forms—or more technically, polymorphs—of FeF3·3H2O are known, the α and β forms. These are prepared by evaporation of an HF solution containing Fe3+ at room temperature (α form) and above 50 °C (β form). The space group of the β form is P4/m, and the α form maintains a P4/m space group with a J6 substructure. The solid α form is unstable and converts to the β form within days. The two forms are distinguished by their difference in quadrupole splitting from their Mössbauer spectra.
Iron(III) fluoride	Preparation, occurrence, reactions	Anhydrous iron(III) fluoride is prepared by treating virtually any anhydrous iron compound with fluorine. More practically and like most metal fluorides, it is prepared by treating the corresponding chloride with hydrogen fluoride: FeCl3 + 3 HF → FeF3 + 3 HClIt also forms as a passivating film upon contact between iron (and steel) and hydrogen fluoride. The hydrates crystallize from aqueous hydrofluoric acid.The material is a fluoride acceptor. With xenon hexafluoride it forms [FeF4][XeF5].Pure FeF3 is not yet known among minerals. However, hydrated form is known as the very rare fumarolic mineral topsøeite. Generally a trihydrate, its chemistry is slightly more complex: FeF[F0.5(H2O)0.5]4·H2O.
Iron(III) fluoride	Applications	The primary commercial use of iron(III) fluoride in the production of ceramics.Some cross coupling reaction are catalyzed by ferric fluoride-based compounds. Specifically the coupling of biaryl compounds are catalyzed by hydrated iron(II) fluoride complexes of N-heterocyclic carbene ligands. Other metal fluorides also catalyse similar reactions. Iron(III) fluoride has also been shown to catalyze chemoselective addition of cyanide to aldehydes to give the cyanohydrins.
Iron(III) fluoride	Safety	The anhydrous material is a powerful dehydrating agent. The formation of ferric fluoride may have been responsible for the explosion of a cylinder of hydrogen fluoride gas.
ATtiny microcontroller comparison chart	ATtiny microcontroller comparison chart	ATtiny (also known as TinyAVR) is a subfamily of the popular 8-bit AVR microcontrollers, which typically has fewer features, fewer I/O pins, and less memory than other AVR series chips. The first members of this family were released in 1999 by Atmel (later acquired by Microchip Technology in 2016).
ATtiny microcontroller comparison chart	Features	ATtiny microcontrollers specifically excludes various common features, such as: USB peripheral, DMA controller, crypto engine, or an external memory bus. The following table summarizes common features of the ATtiny microcontrollers, for easy comparison. This table is not meant to be an unabridged feature list.
ATtiny microcontroller comparison chart	Features	Notes Package column - the number after the dash is the number of pins on the package. DIP packages in this table are 0.3 inches (7.62 mm) row-to-row. SOwww means SOIC package with a case width of 'www' in thousandth of an inch. Though some package types are known by more than one name, a common name was chosen to make it easier to compare packages.
ATtiny microcontroller comparison chart	Features	UART/I²C/SPI columns - green cell means a dedicated peripheral, * yellow cell means a multi-feature peripheral that is chosen by setting configuration bits. Most USART peripherals support a minimum choice between UART or SPI, where as some might support additional choices, such as LIN, IrDA, RS-485. Timers column - more recent families have wider timers. RTT is a 16-bit Real Time Timer that is driven by a 32.768KHz clock, though Microchip calls it RTC for Real Time Counter (easily confused to mean Real Time Clock). ADC pins column - the total number of analog channels that are accessible via pins that multiplex into the ADC input. Most parts have one ADC, a few have two ADC.
ATtiny microcontroller comparison chart	Features	Pgm/Dbg column - flash programming and debugging protocols: HVPP means High Voltage Parallel Programming 12V protocol, HVSP means High Voltage Serial Programming 12V protocol, ISP means In-System Programmable protocol, uses SPI to program the internal flash. TPI is Tiny Programming Interface. dW means debugWIRE protocol. UPDI means Unified Program and Debug Interface protocol (newest).AbbreviationsTWI: Many of Atmels microcontrollers contain built-in support for interfacing to a two-wire bus, called Two-Wire Interface. This is essentially the same thing as the I²C interface by Philips, but that term is avoided in Atmel's documentation due to trademark issues.
ATtiny microcontroller comparison chart	Features	USI: Universal Serial Interface (not to be confused with USB). The USI is a multi-purpose hardware communication module. With appropriate software support, it can be used to implement an SPI, I²C or UART interface. USART peripherals have more features than USI peripherals.
ATtiny microcontroller comparison chart	Timeline	The following table lists each ATtiny microcontroller by the first release date of each datasheet.
ATtiny microcontroller comparison chart	Development boards	The following are ATtiny development boards sold by Microchip Technology: ATtiny104 Xplained Nano ATtiny416 Xplained Nano ATtiny817 AVR Parrot ATtiny817 Xplained Mini ATtiny817 Xplained Pro ATtiny3217 Xplained Pro
Memory bandwidth	Memory bandwidth	Memory bandwidth is the rate at which data can be read from or stored into a semiconductor memory by a processor. Memory bandwidth is usually expressed in units of bytes/second, though this can vary for systems with natural data sizes that are not a multiple of the commonly used 8-bit bytes.
Memory bandwidth	Memory bandwidth	Memory bandwidth that is advertised for a given memory or system is usually the maximum theoretical bandwidth. In practice the observed memory bandwidth will be less than (and is guaranteed not to exceed) the advertised bandwidth. A variety of computer benchmarks exist to measure sustained memory bandwidth using a variety of access patterns. These are intended to provide insight into the memory bandwidth that a system should sustain on various classes of real applications.
Memory bandwidth	Measurement conventions	There are three different conventions for defining the quantity of data transferred in the numerator of "bytes/second": The bcopy convention: counts the amount of data copied from one location in memory to another location per unit time. For example, copying 1 million bytes from one location in memory to another location in memory in one second would be counted as 1 million bytes per second. The bcopy convention is self-consistent, but is not easily extended to cover cases with more complex access patterns, for example three reads and one write.
Memory bandwidth	Measurement conventions	The Stream convention: sums the amount of data that the application code explicitly reads plus the amount of data that the application code explicitly writes. Using the previous 1 million byte copy example, the STREAM bandwidth would be counted as 1 million bytes read plus 1 million bytes written in one second, for a total of 2 million bytes per second. The STREAM convention is most directly tied to the user code, but may not count all the data traffic that the hardware is actually required to perform.
Memory bandwidth	Measurement conventions	The hardware convention: counts the actual amount of data read or written by the hardware, whether the data motion was explicitly requested by the user code or not. Using the same 1 million byte copy example, the hardware bandwidth on computer systems with a write allocate cache policy would include an additional 1 million bytes of traffic because the hardware reads the target array from memory into cache before performing the stores. This gives a total of 3 million bytes per second actually transferred by the hardware. The hardware convention is most directly tied to the hardware, but may not represent the minimum amount of data traffic required to implement the user's code.For example, some computer systems have the ability to avoid write allocate traffic using special instructions, leading to the possibility of misleading comparisons of bandwidth based on different amounts of data traffic performed.
Memory bandwidth	Bandwidth computation and nomenclature	The nomenclature differs across memory technologies, but for commodity DDR SDRAM, DDR2 SDRAM, and DDR3 SDRAM memory, the total bandwidth is the product of: Base DRAM clock frequency Number of data transfers per clock: Two, in the case of "double data rate" (DDR, DDR2, DDR3, DDR4) memory.
Memory bandwidth	Bandwidth computation and nomenclature	Memory bus (interface) width: Each DDR, DDR2, or DDR3 memory interface is 64 bits wide. Those 64 bits are sometimes referred to as a "line." Number of interfaces: Modern personal computers typically use two memory interfaces (dual-channel mode) for an effective 128-bit bus width.For example, a computer with dual-channel memory and one DDR2-800 module per channel running at 400 MHz would have a theoretical maximum memory bandwidth of: 400,000,000 clocks per second × 2 lines per clock × 64 bits per line × 2 interfaces =102,400,000,000 (102.4 billion) bits per second (in bytes, 12,800 MB/s or 12.8 GB/s)This theoretical maximum memory bandwidth is referred to as the "burst rate," which may not be sustainable.
Memory bandwidth	Bandwidth computation and nomenclature	The naming convention for DDR, DDR2 and DDR3 modules specifies either a maximum speed (e.g., DDR2-800) or a maximum bandwidth (e.g., PC2-6400). The speed rating (800) is not the maximum clock speed, but twice that (because of the doubled data rate). The specified bandwidth (6400) is the maximum megabytes transferred per second using a 64-bit width. In a dual-channel mode configuration, this is effectively a 128-bit width. Thus, the memory configuration in the example can be simplified as: two DDR2-800 modules running in dual-channel mode.
Memory bandwidth	Bandwidth computation and nomenclature	Two memory interfaces per module is a common configuration for PC system memory, but single-channel configurations are common in older, low-end, or low-power devices. Some personal computers and most modern graphics cards use more than two memory interfaces (e.g., four for Intel's LGA 2011 platform and the NVIDIA GeForce GTX 980). High-performance graphics cards running many interfaces in parallel can attain very high total memory bus width (e.g., 384 bits in the NVIDIA GeForce GTX TITAN and 512 bits in the AMD Radeon R9 290X using six and eight 64-bit interfaces respectively).
Memory bandwidth	ECC bits	In systems with error-correcting memory (ECC), the additional width of the interfaces (typically 72 rather than 64 bits) is not counted in bandwidth specifications because the extra bits are unavailable to store user data. ECC bits are better thought of as part of the memory hardware rather than as information stored in that hardware.
Cyclic language	Cyclic language	In computer science, more particularly in formal language theory, a cyclic language is a set of strings that is closed with respect to repetition, root, and cyclic shift.
Cyclic language	Definition	If A is a set of symbols, and A* is the set of all strings built from symbols in A, then a string set L ⊆ A* is called a formal language over the alphabet A. The language L is called cyclic if ∀w∈A. ∀n>0. w ∈ L ⇔ wn ∈ L, and ∀v,w∈A. vw ∈ L ⇔ wv ∈ L,where wn denotes the n-fold repetition of the string w, and vw denotes the concatenation of the strings v and w.: Def.1
Cyclic language	Examples	For example, using the alphabet A = {a, b }, the language is cyclic, but not regular.: Exm.2 However, L is context-free, since M = { an1bn1 an2bn2 ... ank bnk : ni ≥ 0 } is, and context-free languages are closed under circular shift; L is obtained as circular shift of M.
Mothing	Mothing	Mothing or moth-watching is a form of wildlife observation where moths are observed, both for recreation and for citizen science activities. It is analogous to birdwatching, but for moths.Many bird observatories also run moth traps.
Mothing	Techniques	Mothing is frequently done with the aid of attractants, such as sugary solutions painted in tree trunks or using light. There are also moth traps, which are designed specifically for mothing, with do-it-yourself and commercial versions.
Least distance of distinct vision	Least distance of distinct vision	In optometry, the least distance of distinct vision (LDDV) or the reference seeing distance (RSD) is the closest someone with "normal" vision (20/20 vision) can comfortably look at something. In other words, LDDV is the minimum comfortable distance between the naked human eye and a visible object. The magnifying power (M) of a lens with focal length (f in millimeters) when viewed by the naked human eye can be calculated as: 250 f.
Battery tester	Battery tester	A battery tester is an electronic device intended for testing the state of an electric battery, going from a simple device for testing the charge actually present in the cells and/or its voltage output, to a more comprehensive testing of the battery's condition, namely its capacity for accumulating charge and any possible flaws affecting the battery's performance and security.
Battery tester	Simple battery testers	The most simple battery tester is a DC ammeter, that indicates the battery's charge rate. DC voltmeters can be used to estimate the charge rate of a battery, provided that its nominal voltage is known.
Battery tester	Integrated battery testers	There are many types of integrated battery testers, each one corresponding to a specific condition testing procedure, according to the type of battery being tested, such as the “421” test for lead-acid vehicle batteries. Their common principle is based on the empirical fact that after having applied a given current for a given number of seconds to the battery, the resulting voltage output is related to the battery's overall condition, when compared to a healthy battery's output.
Dow Jones Transportation Average	Dow Jones Transportation Average	The Dow Jones Transportation Average (DJTA, also called the "Dow Jones Transports") is a U.S. stock market index from S&P Dow Jones Indices of the transportation sector, and is the most widely recognized gauge of the American transportation sector. It is the oldest stock index still in use, even older than its better-known relative, the Dow Jones Industrial Average (DJIA).
Dow Jones Transportation Average	Components	The index is a running average of the stock prices of twenty transportation corporations, with each stock's price weighted to adjust for stock splits and other factors. As a result, it can change at any time the markets are open. The figure mentioned in news reports is usually the figure derived from the prices at the close of the market for the day.
Dow Jones Transportation Average	Components	Changes in the index's composition are rare, and generally occur only after corporate acquisitions or other dramatic shifts in a component's core business. Should such an event require that one component be replaced, the entire index is reviewed. As of December 14, 2021, the index consists of the following 20 companies: Alaska Air Group replaced AMR Corporation on December 2, 2011, after AMR corp. filed for bankruptcy protection.Effective October 30, 2012, Kirby Corp. replaced Overseas Shipholding Group, Inc.Effective October 1, 2014, Avis Budget Group Inc. replaced GATX Corporation.On October 15, 2015, American Airlines Group replaced Con-way.Effective December 14, 2021, Old Dominion Freight Line replaced Kansas City Southern.
Dow Jones Transportation Average	History	The average was created on July 3, 1884, by Charles Dow, co-founder of Dow Jones & Company, as part of the "Customer's Afternoon Letter". At its inception, it consisted of eleven transportation companies—nine railroads and two non-rail companies: Chicago, Milwaukee and St. Paul Railway Chicago and North Western Railway Delaware, Lackawanna and Western Railroad Lake Shore and Michigan Southern Railway Louisville and Nashville Railroad Missouri Pacific Railway New York Central Railroad Northern Pacific Railroad preferred stock Pacific Mail Steamship Company (not a railroad) Union Pacific Railway Western Union (not a railroad)As a result of the dominating presence of railroads, the Transportation Average was often referred to as "rails" in financial discussions in the early and middle part of the 20th century.
Dow Jones Transportation Average	Use in Dow theory	The Transportation Average is an important factor in Dow theory.
Dow Jones Transportation Average	Price history	In 1964, the index first broke 200, slightly over where it was in 1929. In 1983, the index first broke 500. In 1987, the index broke 1000. It closed at 2146.89 on March 9, 2009, having a low coincident with some other indices; this was a bit above its low of 1942.19 on March 11, 2003.
Dow Jones Transportation Average	Price history	The index broke above the mid-5000s to begin a run of record highs on January 15, 2013, at a time when the better-known Industrials stood about 5% below all-time highs achieved more than five years earlier. By May, the Industrials and all other major indexes except the NASDAQ group were making all-time highs, including the Transports, which reached new closing and intraday records above the 6,500 level. On October 24, 2013, the Transports closed at 7,022.79, for its first close above 7,000 points. It closed the year at a record high of 7,400.57. On May 27, 2014, it first closed above 8,000 points. The index closed above 9000 on November 10, 2014. At the close of 2014, the index hit 9139.92. At the close of 2015, the index hit 7508.71, a loss of 17.85% on the year.
Dow Jones Transportation Average	Annual returns	The following table shows the price return of the Dow Jones Transportation Average, which was calculated back to 1924.
Dow Jones Transportation Average	Investing	There is no fund that tracks this index. There are funds that have a similar behavior, such as iShares Transportation Average ETF (NYSE Arca: IYT).
Hit the ball twice	Hit the ball twice	Hit the ball twice, or "double-hit", is a method of dismissal in the sport of cricket. Its occurrence in modern cricket is exceptionally rare.
Hit the ball twice	Definition	Law 34.1 of the Laws of Cricket states: 34.1 Out Hit the ball twice 34.1.1 The striker is out Hit the ball twice if, while the ball is in play, it strikes any part of his/her person or is struck by his/her bat and, before the ball has been touched by a fielder, the striker wilfully strikes it again with his/her bat or person, other than a hand not holding the bat, except for the sole purpose of guarding his/her wicket.
Hit the ball twice	Definition	34.1.2 For the purpose of this Law ‘struck’ or ‘strike’ shall include contact with the person of the striker. A player can hit the ball twice in order to prevent it from hitting his/her stumps but not with a hand that is not in contact with the bat and not if doing so prevents a catch being taken (in which case they would be out obstructing the field). The bowler does not get credit for the wicket.
Hit the ball twice	History	Cricket is often considered to be a rather gentle pastime but it has a history of extreme violence. In its early days, before the modern rules had universal effect, batsmen could go to almost any lengths to avoid being out. They could obstruct the fielders and they could hit the ball as many times as necessary to preserve their wicket. This had fatal consequences on more than one occasion and, ultimately, strict rules were introduced to prevent the batsman from physically attacking the fielders.
Hit the ball twice	History	In 1622, several parishioners of Boxgrove, near Chichester in West Sussex, were prosecuted for playing cricket in a churchyard on Sunday 5 May. There were three reasons for the prosecution: one was that it contravened a local by-law; another reflected concern about church windows which may or may not have been broken; the third was that "a little childe had like to have her braines beaten out with a cricket batt".The latter situation was because the rules at the time allowed the batsman to hit the ball more than once and so fielding near the batsman was very hazardous, as two later incidents confirm.
Hit the ball twice	History	In 1624, a fatality occurred at Horsted Keynes in East Sussex when a fielder called Jasper Vinall was struck on the head by the batsman, Edward Tye, who was trying to hit the ball a second time to avoid being caught. Vinall is thus the earliest known cricketing fatality. The matter was recorded in a coroner's court, which returned a verdict of misadventure.In 1647, another fatality was recorded at Selsey, West Sussex, when a fielder called Henry Brand was hit on the head by a batsman trying to hit the ball a second time.It is not known when the rules were changed to outlaw striking for the ball a second time or when the offence of obstructing the field was introduced, but both those rules were clearly stated in the 1744 codification of the Laws of Cricket, which were drawn up by the London Cricket Club and are believed to be based on a much earlier code that has been lost.The first definite record of a batsman being dismissed for hitting the ball twice occurred in the Hampshire v Kent match at Windmill Down on 13–15 July 1786. Tom Sueter of Hampshire, who had scored 3, was the player in question, as recorded in Scores and Biographies.
Hit the ball twice	Unusual dismissal	An example of the dismissal occurred in 1906 when John King, playing for Leicestershire against Surrey at The Oval tried to score a run after playing the ball twice to avoid getting bowled. Had he not tried to score a run, he would not have been out. Based on the history of the game, this method of dismissal is the second rarest after timed out, recorded merely on twenty-one occasions, although in modern times timed out has become more common.One relatively recent example of a batsman being out "Hit the ball twice" was Kurt Wilkinson's dismissal when playing for Barbados against Rest of Leeward Islands in the 2002–03 Red Stripe Bowl. The dismissal was controversial as there was doubt as to whether Wilkinson had "wilfully" struck the ball twice as required under the relevant law of cricket.
Water hole (radio)	Water hole (radio)	The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum between 1420 and 1662 megahertz, corresponding to wavelengths of 21 and 18 centimeters, respectively. It is a popular observing frequency used by radio telescopes in radio astronomy.The strongest hydroxyl radical spectral line radiates at 18 centimeters, and atomic hydrogen at 21 centimeters (the hydrogen line). These two molecules, which combine to form water, are widespread in interstellar gas, which means this gas tends to absorb radio noise at these frequencies. Therefore, the spectrum between these frequencies forms a relatively "quiet" channel in the interstellar radio noise background.
Water hole (radio)	Water hole (radio)	Bernard M. Oliver, who coined the term in 1971, theorized that the waterhole would be an obvious band for communication with extraterrestrial intelligence, hence the name, which is a pun: in English, a watering hole is a vernacular reference to a common place to meet and talk. Several programs involved in the search for extraterrestrial intelligence, including SETI@home, search in the waterhole radio frequencies.
Galactic Emission Mapping	Galactic Emission Mapping	The Galactic Emission Mapping survey (GEM) is an international project with the goal of making a precise map of the electromagnetic spectrum of our galaxy at low frequencies (radio and microwaves).
Galactic Emission Mapping	Description of the project	The GEM Radio Telescope measures the radio emission of our galaxy in five frequencies, between 408 MHz and 10 GHz, from different places of the earth. This data will be used to calibrate other telescopes, more specifically the Planck Surveyor, and will give the means to filter the Cyclotron Radiation and the free free radiation from other maps in a way that the only radiation left on the map is the Cosmic Microwave Background.
Galactic Emission Mapping	Description of the project	The telescope is in construction at Pampilhosa da Serra, Portugal, but the receptor has already made measurements in Cachoeira Paulista, (Brasil), in Antártica, in Bishop (U.S.), Villa de Leyva (Colombia) and in Tenerife (Canary Islands). The main reflector has a parabolic form of 5,5m of diameter.The telescope was projected and is operated by an international collaboration coordinated by the University of California, Berkeley and by the Lawrence Berkeley National Laboratory, under the guidance of George Smoot, awarded with the Nobel Prize in Physics in 2006.
Galactic Emission Mapping	Description of the project	In Brasil, the radio telescope is under the responsibility of the Instituto Nacional de Pesquisas Espaciais ( National Institute of Space Research) and counts with the participation of the Astrophysics group of the Universidade Federal de Itajubá (Itajubá Federal University). Portugal joined the project in 2005 through the Instituto de Telecomunicações of Aveiro (Telecommunications institute of Aveiro), who is responsible for the planning and construction of the radio telescope.
Galactic Emission Mapping	Description of the project	GEM in Portugal Scanning Process In Portugal the radio telescope will perform scans by rotating on its base at a speed greater than one rotation per minute, therefore avoiding the error fluctuations caused by water vapour in the atmosphere. This scanning process will provide an important contribution to the data processing.
Galactic Emission Mapping	Description of the project	Telescope A Ground Shield will be built to avoid signal contamination with thermal radiation that may come from below the horizon, to reflect side lobes to the sky and to reduce the noise originating from diffraction from the edges of the reflector to the receiver. This will be made possible by an aluminium grid surrounding the radio telescope, which is 10 meters wide but only 8 meters high because it will be inclined towards the exterior.
Galactic Emission Mapping	Description of the project	The edges will be curved with a radius larger than ¼ of the wavelength so that diffraction is reduced. Localization The antenna is located at Pampilhosa da Serra at an altitude of 800m above sea level. This location was chosen because it is surrounded by a mountain range which peaks at about 1000m above sea level, which give a natural "shielding" from the electromagnetic noise of the neighboring cities.
Galactic Emission Mapping	Description of the project	The same reason that made this location a good choice also created additional problems, since many of the necessary infrastructures had to be prepared and installed. The Telescope foundations were studied by the Département of Civil Engineering of the Universidade de Aveiro and the city hall of Pampilhosa da Serra offered 120 tons of concrete. A new connection to the electric grid was made taking into account the size of the transformer to avoid noise in the observed frequencies. This was necessary because the wavelength of the emitted radiation is close to size of the transformer. A small meteorologic station was also installed to measure the wind intensity and help prevent against wind damages on the telescope.
Galactic Emission Mapping	Description of the project	A second telescope is planned on the same site, to study solar phenomena.
Nonlinear eigenproblem	Nonlinear eigenproblem	In mathematics, a nonlinear eigenproblem, sometimes nonlinear eigenvalue problem, is a generalization of the (ordinary) eigenvalue problem to equations that depend nonlinearly on the eigenvalue. Specifically, it refers to equations of the form M(λ)x=0, where x≠0 is a vector, and M is a matrix-valued function of the number λ . The number λ is known as the (nonlinear) eigenvalue, the vector x as the (nonlinear) eigenvector, and (λ,x) as the eigenpair. The matrix M(λ) is singular at an eigenvalue λ
Nonlinear eigenproblem	Definition	In the discipline of numerical linear algebra the following definition is typically used.Let Ω⊆C , and let M:Ω→Cn×n be a function that maps scalars to matrices. A scalar λ∈C is called an eigenvalue, and a nonzero vector x∈Cn is called a right eigevector if M(λ)x=0 . Moreover, a nonzero vector y∈Cn is called a left eigevector if yHM(λ)=0H , where the superscript H denotes the Hermitian transpose. The definition of the eigenvalue is equivalent to det (M(λ))=0 , where det () denotes the determinant.The function M is usually required to be a holomorphic function of λ (in some domain Ω ).
Nonlinear eigenproblem	Definition	In general, M(λ) could be a linear map, but most commonly it is a finite-dimensional, usually square, matrix.
Nonlinear eigenproblem	Definition	Definition: The problem is said to be regular if there exists a z∈Ω such that det (M(z))≠0 . Otherwise it is said to be singular.Definition: An eigenvalue λ is said to have algebraic multiplicity k if k is the smallest integer such that the k th derivative of det (M(z)) with respect to z , in λ is nonzero. In formulas that det (M(z))dzk\|z=λ≠0 but det (M(z))dzℓ\|z=λ=0 for ℓ=0,1,2,…,k−1 .Definition: The geometric multiplicity of an eigenvalue λ is the dimension of the nullspace of M(λ)
Nonlinear eigenproblem	Special cases	The following examples are special cases of the nonlinear eigenproblem. The (ordinary) eigenvalue problem: M(λ)=A−λI. The generalized eigenvalue problem: M(λ)=A−λB. The quadratic eigenvalue problem: M(λ)=A0+λA1+λ2A2. The polynomial eigenvalue problem: M(λ)=∑i=0mλiAi. The rational eigenvalue problem: M(λ)=∑i=0m1Aiλi+∑i=1m2Biri(λ), where ri(λ) are rational functions. The delay eigenvalue problem: M(λ)=−Iλ+A0+∑i=1mAie−τiλ, where τ1,τ2,…,τm are given scalars, known as delays.
Nonlinear eigenproblem	Jordan chains	Definition: Let (λ0,x0) be an eigenpair. A tuple of vectors (x0,x1,…,xr−1)∈Cn×Cn×⋯×Cn is called a Jordan chain iffor ℓ=0,1,…,r−1 , where M(k)(λ0) denotes the k th derivative of M with respect to λ and evaluated in λ=λ0 . The vectors x0,x1,…,xr−1 are called generalized eigenvectors, r is called the length of the Jordan chain, and the maximal length a Jordan chain starting with x0 is called the rank of x0 .Theorem: A tuple of vectors (x0,x1,…,xr−1)∈Cn×Cn×⋯×Cn is a Jordan chain if and only if the function M(λ)χℓ(λ) has a root in λ=λ0 and the root is of multiplicity at least ℓ for ℓ=0,1,…,r−1 , where the vector valued function χℓ(λ) is defined as
Nonlinear eigenproblem	Mathematical software	The eigenvalue solver package SLEPc contains C-implementations of many numerical methods for nonlinear eigenvalue problems. The NLEVP collection of nonlinear eigenvalue problems is a MATLAB package containing many nonlinear eigenvalue problems with various properties. The FEAST eigenvalue solver is a software package for standard eigenvalue problems as well as nonlinear eigenvalue problems, designed from density-matrix representation in quantum mechanics combined with contour integration techniques. The MATLAB toolbox NLEIGS contains an implementation of fully rational Krylov with a dynamically constructed rational interpolant. The MATLAB toolbox CORK contains an implementation of the compact rational Krylov algorithm that exploits the Kronecker structure of the linearization pencils. The MATLAB toolbox AAA-EIGS contains an implementation of CORK with rational approximation by set-valued AAA. The MATLAB toolbox RKToolbox (Rational Krylov Toolbox) contains implementations of the rational Krylov method for nonlinear eigenvalue problems as well as features for rational approximation. The Julia package NEP-PACK contains many implementations of various numerical methods for nonlinear eigenvalue problems, as well as many benchmark problems. The review paper of Güttel & Tisseur contains MATLAB code snippets implementing basic Newton-type methods and contour integration methods for nonlinear eigenproblems.
Nonlinear eigenproblem	Eigenvector nonlinearity	Eigenvector nonlinearities is a related, but different, form of nonlinearity that is sometimes studied. In this case the function M maps vectors to matrices, or sometimes hermitian matrices to hermitian matrices.
CARMENES survey	CARMENES survey	The CARMENES survey (Calar Alto high-Resolution search for M-dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is a project to examine approximately 300 M-dwarf stars for signs of exoplanets with the CARMENES instrument on the Spanish Calar Alto's 3.5m telescope.Operating since 2016, it aims to find Earth-sized exoplanets around 2 MEarth (Earth masses) using Doppler spectroscopy (also called the radial velocity method). More than 20 exoplanets have been found through CARMENES, among them Teegarden b, considered one of the most potentially habitable exoplanets. Another potentially habitable planet found is GJ 357 d.
Triple DES	Triple DES	In cryptography, Triple DES (3DES or TDES), officially the Triple Data Encryption Algorithm (TDEA or Triple DEA), is a symmetric-key block cipher, which applies the DES cipher algorithm three times to each data block. The Data Encryption Standard's (DES) 56-bit key is no longer considered adequate in the face of modern cryptanalytic techniques and supercomputing power. A CVE released in 2016, CVE-2016-2183 disclosed a major security vulnerability in DES and 3DES encryption algorithms. This CVE, combined with the inadequate key size of DES and 3DES, led to NIST deprecating DES and 3DES for new applications in 2017, and for all applications by the end of 2023. It has been replaced with the more secure, more robust AES.
Triple DES	Triple DES	While the government and industry standards abbreviate the algorithm's name as TDES (Triple DES) and TDEA (Triple Data Encryption Algorithm), RFC 1851 referred to it as 3DES from the time it first promulgated the idea, and this namesake has since come into wide use by most vendors, users, and cryptographers.
Triple DES	History	In 1978, a triple encryption method using DES with two 56-bit keys was proposed by Walter Tuchman; in 1981 Merkle and Hellman proposed a more secure triple key version of 3DES with 112 bits of security.
Triple DES	Standards	The Triple Data Encryption Algorithm is variously defined in several standards documents: RFC 1851, The ESP Triple DES Transform (approved in 1995) ANSI ANS X9.52-1998 Triple Data Encryption Algorithm Modes of Operation (approved in 1998, withdrawn in 2008) FIPS PUB 46-3 Data Encryption Standard (DES) (approved in 1999, withdrawn in 2005) NIST Special Publication 800-67 Revision 2 Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher (approved in 2017) ISO/IEC 18033-3:2010: Part 3: Block ciphers (approved in 2005)
Triple DES	Algorithm	The original DES cipher's key size of 56 bits was generally sufficient when that algorithm was designed, but the availability of increasing computational power made brute-force attacks feasible. Triple DES provides a relatively simple method of increasing the key size of DES to protect against such attacks, without the need to design a completely new block cipher algorithm.
Triple DES	Algorithm	A naive approach to increase strength of a block encryption algorithm with short key length (like DES) would be to use two keys (K1,K2) instead of one, and encrypt each block twice: plaintext )) . If the original key length is n bits, one would hope this scheme provides security equivalent to using key 2n bits long. Unfortunately, this approach is vulnerable to meet-in-the-middle attack: given a known plaintext pair (x,y) , such that y=EK2(EK1(x)) , one can recover the key pair (K1,K2) in 2n+1 steps, instead of the 22n steps one would expect from an ideally secure algorithm with 2n bits of key.
Triple DES	Algorithm	Therefore, Triple DES uses a "key bundle" that comprises three DES keys, K1 , K2 and K3 , each of 56 bits (excluding parity bits). The encryption algorithm is: ciphertext plaintext ))). That is, DES encrypt with K1 , DES decrypt with K2 , then DES encrypt with K3 Decryption is the reverse: plaintext ciphertext ))). That is, decrypt with K3 , encrypt with K2 , then decrypt with K1 Each triple encryption encrypts one block of 64 bits of data. In each case the middle operation is the reverse of the first and last. This improves the strength of the algorithm when using keying option 2 and provides backward compatibility with DES with keying option 3.
Triple DES	Keying options	The standards define three keying options: Keying option 1 All three keys are independent. Sometimes known as 3TDEA or triple-length keys. This is the strongest, with 3 × 56 = 168 independent key bits. It is still vulnerable to meet-in-the-middle attack, but the attack requires 22 × 56 steps. Keying option 2 K1 and K2 are independent, and K3 = K1. Sometimes known as 2TDEA or double-length keys. This provides a shorter key length of 56*2 or 112 bits and a reasonable compromise between DES and Keying option 1, with the same caveat as above. This is an improvement over "double DES" which only requires 256 steps to attack. NIST has deprecated this option. Keying option 3 All three keys are identical, i.e. K1 = K2 = K3.
Triple DES	Keying options	This is backward compatible with DES, since two operations cancel out. ISO/IEC 18033-3 never allowed this option, and NIST no longer allows K1 = K2 or K2 = K3.Each DES key is 8 odd-parity bytes, with 56 bits of key and 8 bits of error-detection. A key bundle requires 24 bytes for option 1, 16 for option 2, or 8 for option 3.
Triple DES	Keying options	NIST (and the current TCG specifications version 2.0 of approved algorithms for Trusted Platform Module) also disallows using any one of the 64 following 64-bit values in any keys (note that 32 of them are the binary complement of the 32 others; and that 32 of these keys are also the reverse permutation of bytes of the 32 others), listed here in hexadecimal (in each byte, the least significant bit is an odd-parity generated bit, it is discarded when forming the effective 56-bit keys): 01.01.01.01.01.01.01.01, FE.FE.FE.FE.FE.FE.FE.FE, E0.FE.FE.E0.F1.FE.FE.F1, 1F.01.01.1F.0E.01.01.0E, 01.01.FE.FE.01.01.FE.FE, FE.FE.01.01.FE.FE.01.01, E0.FE.01.1F.F1.FE.01.0E, 1F.01.FE.E0.0E.01.FE.F1, 01.01.E0.E0.01.01.F1.F1, FE.FE.1F.1F.FE.FE.0E.0E, E0.FE.1F.01.F1.FE.0E.01, 1F.01.E0.FE.0E.01.F1.FE, 01.01.1F.1F.01.01.0E.0E, FE.FE.E0.E0.FE.FE.F1.F1, E0.FE.E0.FE.F1.FE.F1.FE, 1F.01.1F.01.0E.01.0E.01, 01.FE.01.FE.01.FE.01.FE, FE.01.FE.01.FE.01.FE.01, E0.01.FE.1F.F1.01.FE.0E, 1F.FE.01.E0.0E.FE.01.F1, 01.FE.FE.01.01.FE.FE.01, FE.01.01.FE.FE.01.01.FE, E0.01.01.E0.F1.01.01.F1, 1F.FE.FE.1F.0E.FE.FE.0E, 01.FE.E0.1F.01.FE.F1.0E, FE.01.1F.E0.FE.01.0E.F1, E0.01.1F.FE.F1.01.0E.FE, 1F.FE.E0.01.0E.FE.F1.01, 01.FE.1F.E0.01.FE.0E.F1, FE.01.E0.1F.FE.01.F1.0E, E0.01.E0.01.F1.01.F1.01, 1F.FE.1F.FE.0E.FE.0E.FE, 01.E0.01.E0.01.F1.01.F1, FE.1F.FE.1F.FE.0E.FE.0E, E0.1F.FE.01.F1.0E.FE.01, 1F.E0.01.FE.0E.F1.01.FE, 01.E0.FE.1F.01.F1.FE.0E, FE.1F.01.E0.FE.0E.01.F1, E0.1F.01.FE.F1.0E.01.FE, 1F.E0.FE.01.0E.F1.FE.01, 01.E0.E0.01.01.F1.F1.01, FE.1F.1F.FE.FE.0E.0E.FE, E0.1F.1F.E0.F1.0E.0E.F1, 1F.E0.E0.1F.0E.F1.F1.0E, 01.E0.1F.FE.01.F1.0E.FE, FE.1F.E0.01.FE.0E.F1.01, E0.1F.E0.1F.F1.0E.F1.0E, 1F.E0.1F.E0.0E.F1.0E.F1, 01.1F.01.1F.01.0E.01.0E, FE.E0.FE.E0.FE.F1.FE.F1, E0.E0.FE.FE.F1.F1.FE.FE, 1F.1F.01.01.0E.0E.01.01, 01.1F.FE.E0.01.0E.FE.F1, FE.E0.01.1F.FE.F1.01.0E, E0.E0.01.01.F1.F1.01.01, 1F.1F.FE.FE.0E.0E.FE.FE, 01.1F.E0.FE.01.0E.F1.FE, FE.E0.1F.01.FE.F1.0E.01, E0.E0.1F.1F.F1.F1.0E.0E, 1F.1F.E0.E0.0E.0E.F1.F1, 01.1F.1F.01.01.0E.0E.01, FE.E0.E0.FE.FE.F1.F1.FE, E0.E0.E0.E0.F1.F1.F1.F1, 1F.1F.1F.1F.0E.0E.0E.0E, With these restrictions on allowed keys, Triple DES has been reapproved with keying options 1 and 2 only. Generally the three keys are generated by taking 24 bytes from a strong random generator and only keying option 1 should be used (option 2 needs only 16 random bytes, but strong random generators are hard to assert and it's considered best practice to use only option 1).
Triple DES	Encryption of more than one block	As with all block ciphers, encryption and decryption of multiple blocks of data may be performed using a variety of modes of operation, which can generally be defined independently of the block cipher algorithm. However, ANS X9.52 specifies directly, and NIST SP 800-67 specifies via SP 800-38A that some modes shall only be used with certain constraints on them that do not necessarily apply to general specifications of those modes. For example, ANS X9.52 specifies that for cipher block chaining, the initialization vector shall be different each time, whereas ISO/IEC 10116 does not. FIPS PUB 46-3 and ISO/IEC 18033-3 define only the single block algorithm, and do not place any restrictions on the modes of operation for multiple blocks.
Triple DES	Security	In general, Triple DES with three independent keys (keying option 1) has a key length of 168 bits (three 56-bit DES keys), but due to the meet-in-the-middle attack, the effective security it provides is only 112 bits. Keying option 2 reduces the effective key size to 112 bits (because the third key is the same as the first). However, this option is susceptible to certain chosen-plaintext or known-plaintext attacks, and thus it is designated by NIST to have only 80 bits of security. This can be considered insecure, and, as consequence Triple DES has been deprecated by NIST in 2017.
Triple DES	Security	The short block size of 64 bits makes 3DES vulnerable to block collision attacks if it is used to encrypt large amounts of data with the same key. The Sweet32 attack shows how this can be exploited in TLS and OpenVPN. Practical Sweet32 attack on 3DES-based cipher-suites in TLS required 36.6 blocks (785 GB) for a full attack, but researchers were lucky to get a collision just after around 20 blocks, which took only 25 minutes.
Triple DES	Security	The security of TDEA is affected by the number of blocks processed with one key bundle. One key bundle shall not be used to apply cryptographic protection (e.g., encrypt) more than 20 64-bit data blocks. OpenSSL does not include 3DES by default since version 1.1.0 (August 2016) and considers it a "weak cipher".
Triple DES	Usage	As of 2008, the electronic payment industry uses Triple DES and continues to develop and promulgate standards based upon it, such as EMV.Earlier versions of Microsoft OneNote, Microsoft Outlook 2007 and Microsoft System Center Configuration Manager 2012 use Triple DES to password-protect user content and system data. However, in December 2018, Microsoft announced the retirement of 3DES throughout their Office 365 service.Firefox and Mozilla Thunderbird use Triple DES in CBC mode to encrypt website authentication login credentials when using a master password.
Triple DES	Implementations	Below is a list of cryptography libraries that support Triple DES: Botan Bouncy Castle cryptlib Crypto++ Libgcrypt Nettle OpenSSL wolfSSL Trusted Platform Module (alias TPM, hardware implementation)Some implementations above may not include 3DES in the default build, in later or more recent versions.
Rugby socks	Rugby socks	Rugby socks are socks similar to the long socks that are worn in other sports such as association football. They are intended to be worn pulled up just below the knee and cover the shins and calves and are designed to be hardwearing. The knee-high socks for rugby were designed to fit tightly around their calves and feet. The proper fitting is an important requirement that ensures players will not fall down when playing, and moreover, it should assist in preventing blisters.Historically, rugby socks were made from a much thicker weave of material to cope with the more aggressive demands of the game compared to association football, but this is less common, and the two types are barely distinguishable.
ANAPC2	ANAPC2	Anaphase-promoting complex subunit 2 is an enzyme that in humans is encoded by the ANAPC2 gene.A large protein complex, termed the anaphase-promoting complex (APC), or the cyclosome, promotes metaphase-anaphase transition by ubiquitinating its specific substrates such as mitotic cyclins and anaphase inhibitor, which are subsequently degraded by the 26S proteasome. Biochemical studies have shown that the vertebrate APC contains eight subunits. The composition of the APC is highly conserved in organisms from yeast to humans. The product of this gene is a component of the complex and shares sequence similarity with a recently identified family of proteins called cullins, which may also be involved in ubiquitin-mediated degradation.

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