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β-Propiolactone
β-Propiolactone is an organic compound of the lactone family, with a four-membered ring. It is a colorless liquid with a slightly sweet odor, highly soluble in water and miscible with ethanol, acetone, diethyl ether and chloroform.''Merck Index'', 12th Edition, entry 8005. The word propiolactone usually refers to this compound, although it may also refer to α-propiolactone. Production β-Propiolactone is prepared industrially by the reaction of formaldehyde and ethenone in the presence of aluminium- or zinc chloride as catalyst: In the research laboratory, propiolactones have been produced by the carbonylation of epoxides. Reactions and applications It reacts with many nucleophiles in a ring-opening reactions. With water hydrolysis occurs to produce 3-hydroxypropionic acid (hydracryclic acid). Ammonia gives the β-alanine, which is a commercial process. Propiolactone was once widely produced as an intermediate in the production of acrylic acid and its esters. That ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise from both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious. Carcinogens, as mentioned, are agents in the environment capable of contributing to cancer growth. Carcinogens can be categorized into two different types: activation-dependent and activation-independent, and each nature impacts their level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptomyces
''Streptomyces'' is the largest genus of Actinomycetota and the type genus of the family Streptomycetaceae. Over 500 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, and have genomes with high GC content. Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct "earthy" odor that results from production of a volatile metabolite, geosmin. Streptomycetes are characterised by a complex secondary metabolism. They produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomycin, streptomycin, cypemycin, grisemycin, bottromycins and chloramphenicol). The antibiotic streptomycin takes its name directly from ''Streptomyces''. Streptomycetes are infrequent pathogens, though infections in humans, such as mycetoma, can be caused by '' S. somaliensis'' and '' S. sudanensis'', and in plants can be caused by '' S. cavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizopus Delemar
''Rhizopus'' is a genus of common saprophytic fungi on plants and specialized parasites on animals. They are found in a wide variety of organic substances, including "mature fruits and vegetables", jellies, syrups, leather, bread, peanuts, and tobacco. They are multicellular. Some ''Rhizopus'' species are opportunistic human pathogens that often cause fatal disease called mucormycosis. This widespread genus includes at least eight species. ''Rhizopus'' species grow as filamentous, branching hyphae that generally lack cross-walls (i.e., they are coenocytic). They reproduce by forming asexual and sexual spores. In asexual reproduction, sporangiospores are produced inside a spherical structure, the sporangium. Sporangia are supported by a large apophysate columella atop a long stalk, the sporangiophore. Sporangiophores arise among distinctive, root-like rhizoids. In sexual reproduction, a dark zygospore is produced at the point where two compatible mycelia fuse. Upon germinatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphingomonas Paucimobilis
Sphingomonas paucimobilis is a strictly aerobic Gram-negative bacterium that has a single polar flagellum with slow motility. The cell size is around 0.7 x 1.4 μm. It is usually found in soil. As with the other members of the genus, its biochemistry is remarkable in possession of ubiquinone 10 as its major respiratory quinone, and of glycosphingolipids instead of lipopolysaccharides in its cell envelope. It has been implicated in various types of clinical infections. ''S. paucimobilis'' is able to degrade lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...-related biphenyl chemical compounds. References External linksType strain of ''Sphingomonas paucimobilis'' at Bac''Dive'' - the Bacterial Diversity Metadatabase paucimobilis Bacteria described in 1977 {{Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variovorax Paradoxus
''Variovorax paradoxus'' is a gram negative, beta proteobacterium from the genus ''Variovorax''. Strains of ''V. paradoxus'' can be categorized into two groups, hydrogen oxidizers and heterotrophic strains, both of which are aerobic. The genus name Vario-vorax (various-voracious; devouring a variety of substrates) and species name para-doxus (contrary-opinion) reflects both the dichotomy of ''V. paradoxus'' metabolisms, but also its ability to utilize a wide array of organic compounds. Morphology and physiology ''V. paradoxus'' cells are curved rods in shape, with dimensions of 0.3-0.6 x 0.7-3.0 μm in size and normally occur as either single or pairs of cells. Typically, cells have 1-3 peritrichous, degenerate flagella. Colonies of ''V. paradoxus'' are yellow-green in colour, due to the production of carotenoid pigments, and often have an iridescent sheen. Colony shape is normally convex, round and smooth, but can also display flat, undulate margins. ''V. paradoxus'' grows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidovorax
''Acidovorax'' is a genus of within the family Comamonadaceae. The genus contains some plant pathogens, such as ''Acidovorax avenae,'' which causes bacterial fruit blotch Bacterial fruit blotch (BFB) affects cucurbit plants around the world and can be a serious threat to farmers because it spreads through contaminated seed. BFB is the result of an infection by Gram-negative '' Acidovorax citrulli'' bacteria, which ... on cucurbit crops.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual of Systematic Bacteriology, Volume Two: The Proteobacteria, Part C: The Alpha-, Beta-, Delta-, and Epsilonproteobacteria. New York, New York: Springer. Other ''Acidovorax'' sp. perform Fe(II) oxidation in anaerobic environments, forming iron minerals in the soil. References External links''Acidovorax''LPSN List of Prokaryotic names with Standing in Nomenclature Comamonadaceae Bacteria genera {{betaproteobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centers For Disease Control And Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgia. The agency's main goal is the protection of public health and safety through the control and prevention of disease, injury, and disability in the US and worldwide. The CDC focuses national attention on developing and applying disease control and prevention. It especially focuses its attention on infectious disease, food borne pathogens, environmental health, occupational safety and health, health promotion, injury prevention and educational activities designed to improve the health of United States citizens. The CDC also conducts research and provides information on non-infectious diseases, such as obesity and diabetes, and is a founding member of the International Association of National Public Health Institutes. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permissible Exposure Limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational Safety and Health Administration (OSHA). Most of OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970. For chemicals, the chemical regulation is usually expressed in parts per million (ppm), or sometimes in milligrams per cubic meter (mg/m3). Units of measure for physical agents such as noise are specific to the agent. A PEL is usually given as a time-weighted average (TWA), although some are short-term exposure limits (STEL) or ceiling limits. A TWA is the average exposure over a specified period, usually a nominal eight hours. This means that, for limited periods, a worker may be exposed to concentration excursions higher than the PEL, so long as the TWA is not exceeded and any applicab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occupational Safety And Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agency under the Occupational Safety and Health Act OSH Act, which President Richard M. Nixon signed into law on December 29, 1970. OSHA's mission is to "assure safe and healthy working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance". The agency is also charged with enforcing a variety of whistleblower statutes and regulations. OSHA's workplace safety inspections have been shown to reduce injury rates and injury costs without adverse effects on employment, sales, credit ratings, or firm survival. History The Bureau of Labor Standards of the Department of Labor has worked on some work safety issues since its creation in 1922. Economic boom and associated l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Agency For Research On Cancer
The International Agency for Research on Cancer (IARC; french: Centre International de Recherche sur le Cancer, CIRC) 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 collects and publishes surveillance data regarding the occurrence of cancer worldwide. Its IARC monographs programme identifies carcinogenic hazards and evaluates environmental causes of cancer in humans. IARC has its own governing council, and in 1965 the first members were the Federal Republic of Germany, France, Italy, the United Kingdom, and the United States of America. Today, IARC's membership has grown to 27 countries. History In late February 1963, after he experienced his spouse suffering and dying of cancer, journalist and peace activist Yves Poggioli sent a letter to Emmanuel d'Astier de la Vignerie relating his story, and urging support for the creation of an intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
