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Nitrosamines
In organic chemistry, nitrosamines (or more formally ''N''-Nitrosamines) are organic compounds with the chemical structure , where R is usually an alkyl group. They feature a nitroso group () bonded to a deprotonated amine. Most nitrosamines are carcinogenic in nonhuman animals. A 2006 systematic review supports a "positive association between nitrite and nitrosamine intake and gastric cancer, between meat and processed meat intake and gastric cancer and oesophageal cancer, and between preserved fish, vegetable and smoked food intake and gastric cancer, but is not conclusive". Chemistry The organic chemistry of nitrosamines is well developed with regard to their syntheses, their structures, and their reactions. They usually are produced by the reaction of nitrous acid () and secondary amines. :HONO + R2NH -> R2N-NO + H2O The nitrous acid usually arises from protonation of a nitrite. This synthesis method is relevant to the generation of nitrosamines under some biological cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrosamine Formulae V
In organic chemistry, nitrosamines (or more formally ''N''-Nitrosamines) are organic compounds with the chemical structure , where R is usually an alkyl group. They feature a nitroso group () bonded to a deprotonated amine. Most nitrosamines are carcinogenic in nonhuman animals. A 2006 systematic review supports a "positive association between nitrite and nitrosamine intake and gastric cancer, between meat and processed meat intake and gastric cancer and oesophageal cancer, and between preserved fish, vegetable and smoked food intake and gastric cancer, but is not conclusive". Chemistry The organic chemistry of nitrosamines is well developed with regard to their syntheses, their structures, and their reactions. They usually are produced by the reaction of nitrous acid () and secondary amines. :HONO + R2NH -> R2N-NO + H2O The nitrous acid usually arises from protonation of a nitrite. This synthesis method is relevant to the generation of nitrosamines under some biological condi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snus
Snus ( , ) is a tobacco product, originating from a variant of dry snuff in early 18th-century Sweden. It is placed between the upper lip and gum for extended periods, as a form of sublabial administration. Snus is not fermented. Although used similarly to American dipping tobacco, snus does not typically result in the need for spitting and, unlike naswar, snus is steam-pasteurized. The sale of snus is illegal in all the European Union countries except for Sweden. It is the most common type of tobacco product in Norway (which is not in the EU), and is available in Switzerland as well. Some EU countries like Estonia allow the sale of nicotine pouches, snus-like products that contain nicotine but no tobacco. Snus is also available in the United States. Canada makes it difficult to obtain snus through its high taxes on imported tobacco products. Snus has been seen as an alternative to smoking, vaping, chewing, dipping, and dissolvable and snuff tobacco products. Snus usually con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobacco-specific Nitrosamines
Tobacco-specific nitrosamines (TSNAs) comprise one of the most important groups of carcinogens in tobacco products, particularly cigarettes (traditional and electronic) and fermented dipping snuff. Background These nitrosamine carcinogens are formed from nicotine and related compounds by a nitrosation reaction that occurs during the curing and processing of tobacco. Essentially the plant's natural alkaloids combine with nitrate forming the nitrosamines. They are called tobacco-specific nitrosamines because they are found only in tobacco products, and possibly in some other nicotine-containing products. The tobacco-specific nitrosamines are present in cigarette smoke and to a lesser degree in "smokeless" tobacco products such as dipping tobacco and chewing tobacco; additional information has shown that trace amounts of NNN and NNK have been detected in e-cigarettes. They are present in trace amounts in snus. They are important carcinogens in cigarette smoke, along with combustio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Nitrite
Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products. Uses Industrial chemistry The main use of sodium nitrite is for the industrial production of organonitrogen compounds. It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes. Nitroso compounds are produced from nitrites. These are used in the rubber industry. It is used in a variety of metallurgical applications, for phosphatizing and detinning. Sodium nitrite is an effective corrosion inhibitor and is used as an additive in industrial greases, as an aq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chewing Tobacco
Chewing tobacco is a type of smokeless tobacco product that is placed between the cheek and lower gum to draw out its flavor. Some users chew it, others do not. It consists of coarsely chopped aged tobacco that is flavored and often sweetened; it is not ground fine like dipping tobacco. Unwanted juices are then spat. Chewing tobacco may be left as loose leaf or compressed into a small rectangular "plug". Nearly all modern chewing tobaccos are produced by a process of leaf curing, cutting, fermentation, and processing, which may include sweetening and flavoring. Historically, many American chewing-tobacco brands popular during the American Civil War era were made with cigar clippings. Chewing tobacco is a source of nicotine. History Chewing is one of the oldest methods of consuming tobacco. Indigenous peoples of the Americas in both North and South America chewed the leaves of the plant long before the arrival of Europeans. The Southern United States was distinctive for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkyldiazonium
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. General properties and reactivity Arenediazonium cations and related species According to X-ray crystallography the linkage is linear in typical diazonium salts. The bond distance in benzenediazonium tetrafluoroborate is 1.083(3) Å, which is almost identical to that for dinitrogen molecule (N≡N). The linear free energy constants σm and σp indicate that the diazonium group is strongly electron-withdrawing. Thus, the diazonio-substituted phenols and benzoic acids have greatly reduced p''K''a values compared to their unsubstituted counterparts. The p''K''a of phenolic proton of 4-hydroxybenzenediazonium is 3.4, versus 9.9 for phenol itself. In other words, the diazonium group lowers the p''K''a (enhances the acidity) by a million-fold. The stabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Structure
A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together, and can be represented using structural formulae and by molecular models; complete electronic structure descriptions include specifying the occupation of a molecule's molecular orbitals. Structure determination can be applied to a range of targets from very simple molecules (e.g., diatomic oxygen or nitrogen), to very complex ones (e.g., such as protein or DNA). Background Theories of chemical structure were first developed by August Kekulé, Archibald Scott Couper, and Aleksandr Butlerov, among others, from about 1858. These theories were first to state that chemical compounds are not a random cluster of atoms and functional groups, but rather had a definite order ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The American Journal Of Clinical Nutrition
''The American Journal of Clinical Nutrition'' (''AJCN'') is a monthly peer-reviewed biomedical journal in the fields of dietetics and clinical nutrition. The journal was established in 1952 as the ''Journal of Clinical Nutrition'', edited by S.O. Waife and published by the Nutrition Press. It was continued in series under the present title from 1954 and was published by the American Society for Clinical Nutrition (ASCN).Catalog entry at the . It is now published by the .< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascorbic Acid
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) and wrinkles on the face. It is used to prevent and treat scurvy. Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant. Most animals are able to synthesize their own vitamin C. However, apes (including humans) and monkeys (but not all primates), most bats, some rodents, and certain other animals must acquire it from dietary sources. There is some evidence that regular use of supplements may reduce the duration of the common cold, but it does not appear to prevent infection. It is unclear whether supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethylamine
Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. An estimated 270,000 tons were produced in 2005. Structure and synthesis The molecule consists of a nitrogen atom with two methyl substituents and one proton. Dimethylamine is a weak base and the pKa of the ammonium CH3--CH3 is 10.73, a value above methylamine (10.64) and trimethylamine (9.79). Dimethylamine reacts with acids to form salts, such as dimethylamine hydrochloride, an odorless white solid with a melting point of 171.5 °C. Dimethylamine is produced by catalytic reaction of methanol and ammonia at elevated temperatures and high pressure: :2 CH3OH + NH3 → (CH3)2NH + 2 H2O Natural occurrence Dimethylamine is found quite widely distributed in animals and plants, and is present in many foods at the level of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herring
Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of ''Clupea'' (the type genus of the herring family Clupeidae) are recognised, and comprise about 90% of all herrings captured in fisheries. The most abundant of these species is the Atlantic herring, which comprises over half of all herring capture. Fish called herring are also found in the Arabian Sea, Indian Ocean, and Bay of Bengal. Herring played an important role in the history of marine fisheries in Europe, and early in the 20th century, their study was fundamental to the development of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled. Herring are also known as "sil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
