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Acrylamide
Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2. It is a white odorless solid, soluble in water and several organic solvents. From the chemistry perspective, acrylamide is a vinyl-substituted primary amide (CONH2). It is produced industrially mainly as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. Acrylamide forms in burnt areas of food, particularly starchy foods like potatoes, when cooked with high heat, above . Despite health scares following this discovery in 2002, and its classification as a probable carcinogen, acrylamide from diet is thought unlikely to cause cancer in humans; Cancer Research UK categorized the idea that eating burnt food causes cancer as a "myth". Production Acrylamide can be prepared by the hydration of acrylonitrile, which is catalyzed enzymatically: :CH2=CHCN + H2O → CH2=CHC(O)NH2 This reaction also is catalyzed by sulfuric acid as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyacrylamide
Polyacrylamide (abbreviated as PAM or pAAM) is a polymer with the formula (-CH2CHCONH2-). It has a linear-chain structure. PAM is highly water-absorbent, forming a soft gel when hydrated. In 2008, an estimated 750,000,000 kg were produced, mainly for water treatment and the paper and mineral industries. Physicochemical properties Polyacrylamide is a polyolefin. It can be viewed as polyethylene with amide substituents on alternating carbons. Unlike various nylons, polyacrylamide is not a polyamide because the amide groups are not in the polymer backbone. Owing to the presence of the amide (CONH2) groups, alternating carbon atoms in the backbone are stereogenic (colloquially: chiral). For this reason, polyacrylamide exists in atactic, syndiotactic, and isotactic forms, although this aspect is rarely discussed. The polymerization is initiated with radicals and is assumed to be stereorandom. Copolymers and modified polymers Linear polyacrylamide is a water-soluble polymer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potato
The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern United States to southern Chile. Genetic studies show that the cultivated potato has a single origin, in the area of present-day southern Peru and extreme northwestern Bolivia. Potatoes were domesticated there about 7,000–10,000 years ago from a species in the '' S. brevicaule'' complex. Many varieties of the potato are cultivated in the Andes region of South America, where the species is indigenous. The Spanish introduced potatoes to Europe in the second half of the 16th century from the Americas. They are a staple food in many parts of the world and an integral part of much of the world's food supply. Following millennia of selective breeding, there are now over 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses. Acrylonitrile is one of the components of ABS plastic (acrylonitrile butadiene styrene). Structure and basic properties Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses. Production Acrylonitrile was first synthesized by the French chemist Charle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruses and bacteria. Most carcinogens act by creating mutations in DNA that disrupt a cell's normal processes for regulating growth, leading to uncontrolled cellular proliferation. This occurs when the cell's DNA repair processes fail to identify DNA damage allowing the defect to be passed down to daughter cells. The damage accumulates over time. This is typically a multi-step process during which the regulatory mechanisms within the cell are gradually dismantled allowing for unchecked cellular division. The specific mechanisms for carcinogenic activity is unique to each agent and cell type. Carcinogens can be broadly categorized, however, as activation-dependent and activation-independent which relate to the agent's ability to engage dir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asparagine
Asparagine (symbol Asn or N) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain carboxamide, classifying it as a polar (at physiological pH), aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it. It is encoded by the codons AAU and AAC. The one-letter symbol N for asparagine was assigned arbitrarily, with the proposed mnemonic asparagi''N''e; History Asparagine was first isolated in 1806 in a crystalline form by French chemists Louis Nicolas Vauquelin and Pierre Jean Robiquet (then a young assistant). It was isolated from asparagus juice, in which it is abundant, hence the chosen name. It was the first amino acid to be isolated. Three years later, in 1809, Pierre Jean Robiquet identified a substance from l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Acrylate
Methyl acrylate is an organic compound, more accurately the methyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced to make acrylate fiber, which is used to weave synthetic carpets. It is also a reagent in the synthesis of various pharmaceutical intermediates. Owing to the tendency of methyl acrylate to polymerize, samples typically contain an inhibitor such as hydroquinone. Production The standard industrial reaction for producing methyl acrylate is esterification of acrylic acid with methanol under acid catalysis (sulfuric acid, p-toluenesulfonic acid or acidic ion exchangers.). The transesterification is facilitated because methanol and methyl acrylate form a low boiling azeotrope (boiling point 62–63 °C). The patent literature describes a one-pot route involving vapor-phase oxidation of propene or 2-propenal with oxygen in the presence of methanol. Other methods Methyl acrylate can be prepared by debrominatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Toxicology Program
The National Toxicology Program (NTP) is an inter-agency program run by the United States Department of Health and Human Services to coordinate, evaluate, and report on toxicology within public agencies. The National Toxicology Program is headquartered at the National Institute of Environmental Health Sciences (NIEHS). The NIEHS Director, currently Richard Woychik, also concurrently serves as NTP Director. History The program was established in 1978 by Joseph A. Califano Jr., then the United States Secretary of Health, Education, and Welfare (today known as the Secretary of Health and Human Services). The program arose from congressional concerns about the health effects of chemical agents in the environment. In October 1981, Secretary Richard S. Schwiker granted permanent status to the program. Interagency Center for the Evaluation of Alternative Toxicological Methods The NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) supports the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Agency For Research On Cancer
The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and coordinate research into the causes of cancer. It also cancer registry, collects and publishes disease surveillance, surveillance data regarding the occurrence of cancer worldwide. Its IARC monographs programme identifies carcinogenic hazards and evaluates environmental carcinogen, causes of cancer in humans. IARC has its own governing council, and in 1965 the first members were West Germany, France, Italy, the United Kingdom, and the United States of America. Today, IARC's membership has grown to 29 countries. History In late February 1963, after he experienced his spouse suffering and dying of cancer, journalist and Mouvement de la Paix, peace activist Yves Poggioli sent a letter to Emmanuel d'Astier de La Vigerie, Emmanuel d'Astier de la Vignerie relating his story, and urging support for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiological
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and Risk factor (epidemiology), determinants of health and disease conditions in a defined population, and application of this knowledge to prevent diseases. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying Risk factor (epidemiology), risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission (medicine), transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrolysis
Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology The word ''pyrolysis'' is coined from the Greek language, Greek-derived morpheme, elements ''pyro-'' (from Ancient Greek : - "fire, heat, fever") and ''lysis'' ( : - "separation, loosening"). Applications Pyrolysis is most commonly used in the treatment of organic compound, organic materials. It is one of the processes involved in the charring of wood or pyrolysis of biomass. In general, pyrolysis of organic substances produces volatile products and leaves Char (chemistry), char, a carbon-rich solid residue. Extreme pyrolysis, which leaves mostly carbon as the residue, is called carbonization. Pyrolysis is considered one of the steps in the processes of gasification or combustion. Laypeople often confuse pyrolysis gas with syngas. Pyrolysis gas has a high percentage of heavy tar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible Signs and symptoms of cancer, signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in defecation, bowel movements. While these symptoms may indicate cancer, they can also have other causes. List of cancer types, Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor Diet (nutrition), diet, sedentary lifestyle, lack of physical activity or Alcohol abuse, excessive alcohol consumption. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. infectious causes of cancer, Infection with specific viruses, bacteria and parasites is an environmental factor cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
