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Perfluorohexanoic Acid
Perfluorohexanoic acid (PFHxA) is a fluorinated carboxylic acid derivative of hexanoic acid. It is produced as a byproduct in the production of some fluoropolymers, and up until 2002, it was used in the manufacturing process of polytetrafluoroethylene. Perfluorohexanoic acid bioaccumulates and is detectable in the blood nearly every individual in the United States. In 2020 Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ... adopted drinking water standards for 5 previously unregulated PFAS compounds including PFHxA which has a maximum contaminant level (MCL) of 400 parts per billion ( ppb).{{Cite web , date=3 August 2020 , title=New state drinking water standards pave way for expansion of Michigan's PFAS clean-up efforts , url=https://www.michigan.gov/egle/0,9429,7-135- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachionus Calyciflorus
''Brachionus calyciflorus'' is a planktonic rotifer species occurring in freshwater. It is commonly used as a model organism in toxicology, ecology and evolutionary biology. Its advantages include the small size and short generation time (average generation time of ''B. calyciflorus'' is around 2.2 days at 24 °C). Reproduction ''Brachionus calyciflorus'' normally reproduces by cyclical parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development .... Transitions to obligate parthenogenesis have been described. Obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Species complex Like the ''Brachionus plicatilis'' cryptic species complex ''Brachionus c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorinated
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a chemical compound, compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens (F2, Cl2, Br2, I2). Halides are also commonly introduced using salts of the halides and halogen acids. Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride. Organic chemistry Several pathways exist for the halogenation of organic compounds, including free radical halogenation, ketone halogenation, electrophilic halogenation, and halogen addition reaction. The nature of the substrate determines the pathway. The facility of halogenation is influenced by the halogen. Fluorine and chlorine are more elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They at oftentimes have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid (C3H7CO2H) is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named as a "carboxy" or "carboxylic acid" substituent on another ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caproic Acid
Caproic acid, also known as hexanoic acid, is the carboxylic acid derived from hexane with the chemical formula . It is a colorless oily liquid with an odor that is fatty, cheesy, waxy, and like that of goats or other barnyard animals. It is a fatty acid found naturally in various animal fats and oils, and is one of the chemicals that gives the decomposing fleshy seed coat of the ginkgo its characteristic unpleasant odor. It is also one of the components of vanilla and cheese. The primary use of caproic acid is in the manufacture of its esters for use as artificial flavors, and in the manufacture of hexyl derivatives, such as hexylphenols. Salts and esters of caproic acid are known as caproates or hexanoates. Several progestin medications are caproate esters, such as hydroxyprogesterone caproate and gestonorone caproate. Two other acids are named after goats: caprylic acid (C8) and capric acid (C10). Along with caproic acid, they account for 15% of the fat in goat's milk. Capro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
By-product
A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be considered waste: for example, bran, which is a byproduct of the milling of wheat into refined flour, is sometimes composted or burned for disposal, but in other cases, it can be used as a nutritious ingredient in human food or animal feed. Gasoline was once a byproduct of oil refining that later became a desirable commodity as motor fuel. The plastic used in plastic shopping bags also started as a by-product of oil refining. In economics In the context of production, a by-product is the "output from a joint production process that is minor in quantity and/or net realizable value (NRV) when compared with the main products". Because they are deemed to have no influence on reported financial results, by-products do not receive allocations of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluoropolymer
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene under the brand name "Teflon," trademarked by the DuPont Company. History In 1938, polytetrafluoroethylene (DuPont brand name Teflon) was discovered by accident by a recently hired DuPont Ph.D., Roy J. Plunkett. While working with tetrafluoroethylene gas to develop refrigerants, he noticed that a previously pressurized cylinder had no pressure remaining. In dissecting the cylinder, he found a mass of white solid in a quantity similar to that of the tetrafluoroethylene gas. It was determined that this material was a new-to-the-world polymer. Tests showed the substance was resistant to corrosion from most acids, bases and solvents and had better high temperature stability than any other plastic. By early 1941, a crash program was making substantial quantities of P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytetrafluoroethylene
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938. Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid. Polytetrafluoroethylene is used as a non-stick coating for pans and other cookware. It is non-reactive, partly because of the strength of carbon–fluorine bonds, so it is often used in containers and pipework for reactive and corrosive chemicals. Where used as a lubricant, PTFE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioaccumulation
Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated by catabolism and excretion. Thus, the longer the biological half-life of a toxic substance, the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. Bioaccumulation, for example in fish, can be predicted by models. Hypothesis for molecular size cutoff criteria for use as bioaccumulation potential indicators are not supported by data. Biotransformation can strongly modify bioaccumulation of chemicals in an organism. Toxicity induced by metals is associated with bioaccumulation and biomagnification. Storage or uptake of metals faster than the rate at which an organism metabolizes and excretes lead to the accumulation of that metal. The presence of various chemicals and harmful substances in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the circulatory system is also known as ''peripheral blood'', and the blood cells it carries, ''peripheral blood cells''. Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes) and platelets (also called thrombocytes). The most abundant cells in vertebrate blo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michigan
Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the largest by area east of the Mississippi River.''i.e.'', including water that is part of state territory. Georgia is the largest state by land area alone east of the Mississippi and Michigan the second-largest. Its capital is Lansing, and its largest city is Detroit. Metro Detroit is among the nation's most populous and largest metropolitan economies. Its name derives from a gallicized variant of the original Ojibwe word (), meaning "large water" or "large lake". Michigan consists of two peninsulas. The Lower Peninsula resembles the shape of a mitten, and comprises a majority of the state's land area. The Upper Peninsula (often called "the U.P.") is separated from the Lower Peninsula by the Straits of Mackinac, a channel that joins Lak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per- And Polyfluoroalkyl Substances
Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl moiety, –CnF2n+1–. More recently (2021) the Organisation for Economic Co-operation and Development (OECD) expanded the definition, stating that "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS." According to the OECD, at least 4,730 distinct PFASs are known with at least three perfluorinated carbon atoms. A United States Environmental Protection Agency (EPA) toxicity database, DSSTox, lists 14,735 PFASs, while PubChem lists approximately 6 million. A subgroup, the ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
