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C8H5NO2 The molecular formula CHNO (molar mass: 147.13 g/mol, exact mass: 147.032028 u) may refer to: | https://en.wikipedia.org/wiki?curid=23582612 |
C9H7N The molecular formula CHN may refer to: | https://en.wikipedia.org/wiki?curid=23582780 |
C12H24O2 The molecular formula CHO may refer to: | https://en.wikipedia.org/wiki?curid=23582896 |
Agricultural pollution refers to biotic and abiotic byproducts of farming practices that result in contamination or degradation of the environment and surrounding ecosystems, and/or cause injury to humans and their economic interests. The pollution may come from a variety of sources, ranging from point source water pollution (from a single discharge point) to more diffuse, landscape-level causes, also known as non-point source pollution. Management practices play a crucial role in the amount and impact of these pollutants. Management techniques range from animal management and housing to the spread of pesticides and fertilizers in global agricultural practices. Pesticides and herbicides are applied to agricultural land to control pests that disrupt crop production. Soil contamination can occur when pesticides persist and accumulate in soils, which can alter microbial processes, increase plant uptake of the chemical, and are toxic to soil organisms. The extent to which the pesticides and herbicides persist depends on the compound’s unique chemistry, which affects sorption dynamics and resulting fate and transport in the soil environment. Pesticides can also accumulate in animals that eat contaminated pests and soil organisms. In addition, pesticides can be more harmful to beneficial insects, such as pollinators, and to natural enemies of pests (i.e. insects that prey on or parasitize pests) than they are to the target pests themselves | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Pesticide leaching occurs when pesticides mix with water and move through the soil, ultimately contaminating groundwater. The amount of leaching is correlated with particular soil and pesticide characteristics and the degree of rainfall and irrigation. Leaching is most likely to happen if using a water-soluble pesticide, when the soil tends to be sandy in texture; if excessive watering occurs just after pesticide application; if the adsorption ability of the pesticide to the soil is low. Leaching may not only originate from treated fields, but also from pesticide mixing areas, pesticide application machinery washing sites, or disposal areas. Fertilizers are used to provide crops with additional sources of nutrients, such as Nitrogen, Phosphorus, and Potassium, that promote plant growth and increase crop yields. While they are beneficial for plant growth, they can also disrupt natural nutrient and mineral biogeochemical cycles and pose risks to human and ecological health. Nitrogen fertilizers supply plants with forms of nitrogen that are biologically available for plant uptake; namely NO (nitrate) and NH (ammonium). This increases crop yield and agricultural productivity, but it also negatively affects groundwater and surface waters, pollutes the atmosphere, and degrades soil health. Not all of the fertilizer that is applied are taken up by the crops, and the remainder accumulates in the soil or is lost as runoff | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Nitrate fertilizers are much more likely to be lost to the soil profile through runoff because of its high solubility and like charges between the molecule and negatively charged clay particles. High application rates of nitrogen-containing fertilizers combined with the high water-solubility of nitrate leads to increased runoff into surface water as well as leaching into groundwater, thereby causing groundwater pollution. Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause "blue baby syndrome" (acquired methemoglobinemia) in infants and possibly thyroid disease and various types of cancer. Nitrogen fixation, which coverts atmospheric nitrogen (N) to more biologically available forms, and denitrification, which converts biologically available nitrogen compounds to N and NO, are two of the most important metabolic processes involved in the nitrogen cycle because they are the largest inputs and outputs of nitrogen to ecosystems. They allow nitrogen to flow between the atmosphere, which is around 78% nitrogen) and the biosphere. Other significant processes in the nitrogen cycle are nitrification and ammonification which covert ammonium to nitrate or nitrite and organic matter to ammonia respectively. Because these processes keep nitrogen concentrations relatively stable in most ecosystems, a large influx of nitrogen from agricultural runoff can cause serious disruption | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution A common result of this in aquatic ecosystems is eutrophication which in turn creates hypoxic and anoxic conditions - both of which are deadly and/or damaging to many species. Nitrogen fertilization can also release NH gases into the atmosphere which can then be converted into NO compounds. A greater amount of NO compounds in the atmosphere can result in the acidification of aquatic ecosystems and cause various respiratory issues in humans. Fertilization can also release NO which is a greenhouse gas and can facilitate the destruction of ozone (O) in the stratosphere. Soils that receive nitrogen fertilizers can also be damaged. An increase in plant available nitrogen will increase a crop's net primary production, and eventually, soil microbial activity will increase as a result of the larger inputs of nitrogen from fertilizers and carbon compounds through decomposed biomass. Because of the increase in decomposition in the soil, its organic matter content will be depleted which results in lower overall soil health. The most common form of phosphorus fertilizer used in agricultural practices is phosphate (PO), and it is applied in synthetic compounds that incorporate PO or in organic forms such as manure and compost. Phosphorus is an essential nutrient in all organisms because of the roles it plays in cell and metabolic functions such as nucleic acid production and metabolic energy transfers | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution However, most organisms, including agricultural crops, only require a small amount of phosphorus because they have evolved in ecosystems with relatively low amounts of it. Microbial populations in soils are able to convert organic forms of phosphorus to soluble plant available forms such as phosphate. This step is generally bypassed with inorganic fertilizers because it is applied as phosphate or other plant available forms. Any phosphorus that is not taken up by plants is adsorped to soil particles which helps it remain in place. Because of this, it typically enters surface waters when the soil particles it is attached to are eroded as a result of precipitation or stormwater runoff. The amount that enters surface waters is relatively low in comparison to the amount that is applied as fertilizer, but because it acts as a limiting nutrient in most environments, even a small amount can disrupt an ecosystem's natural phosphorus biogeochemical cycles. Although nitrogen plays a role in harmful algae and cyanobacteria blooms that cause eutrophication, excess phosphorus is considered the largest contributing factor due to the fact that phosphorus is often the most limiting nutrient, especially in freshwaters. In addition to depleting oxygen levels in surface waters, algae and cyanobacteria blooms can produce cyanotoxins which are harmful to human and animal health as well as many aquatic organisms. The concentration of cadmium in phosphorus-containing fertilizers varies considerably and can be problematic | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution For example, mono-ammonium phosphate fertilizer may have a cadmium content of as low as 0.14 mg/kg or as high as 50.9 mg/kg. This is because the phosphate rock used in their manufacture can contain as much as 188 mg/kg cadmium (examples are deposits on Nauru and the Christmas islands). Continuous use of high-cadmium fertilizer can contaminate soil and plants. Limits to the cadmium content of phosphate fertilizers has been considered by the European Commission. Producers of phosphorus-containing fertilizers now select phosphate rock based on the cadmium content. Phosphate rocks contain high levels of fluoride. Consequently, the widespread use of phosphate fertilizers has increased soil fluoride concentrations. It has been found that food contamination from fertilizer is of little concern as plants accumulate little fluoride from the soil; of greater concern is the possibility of fluoride toxicity to livestock that ingest contaminated soils. Also of possible concern are the effects of fluoride on soil microorganisms. The concentration of cadmium in phosphorus-containing fertilizers varies considerably and can be problematic. For example, mono-ammonium phosphate fertilizer may have a cadmium content of as low as 0.14 mg/kg or as high as 50.9 mg/kg. This is because the phosphate rock used in their manufacture can contain as much as 188 mg/kg cadmium (examples are deposits on Nauru and the Christmas islands). Continuous use of high-cadmium fertilizer can contaminate soil and plants | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Limits to the cadmium content of phosphate fertilizers has been considered by the European Commission. Producers of phosphorus-containing fertilizers now select phosphate rock based on the cadmium content. Phosphate rocks contain high levels of fluoride. Consequently, the widespread use of phosphate fertilizers has increased soil fluoride concentrations. It has been found that food contamination from fertilizer is of little concern as plants accumulate little fluoride from the soil; of greater concern is the possibility of fluoride toxicity to livestock that ingest contaminated soils. Also of possible concern are the effects of fluoride on soil microorganisms. The radioactive content of the fertilizers varies considerably and depends both on their concentrations in the parent mineral and on the fertilizer production process. Uranium-238 concentrations range can range from 7 to 100 pCi/g in phosphate rock and from 1 to 67 pCi/g in phosphate fertilizers. Where high annual rates of phosphorus fertilizer are used, this can result in uranium-238 concentrations in soils and drainage waters that are several times greater than are normally present. However, the impact of these increases on the risk to human health from radionuclide contamination of foods is very small (less than 0.05 mSv/y). Manures and biosolids contain many nutrients consumed by animals and humans in the form of food. The practice of returning such waste products to agricultural land presents an opportunity to recycle soil nutrients | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution The challenge is that manures and biosolids contain not only nutrients such as carbon, nitrogen, and phosphorus, but they may also contain contaminants, including pharmaceuticals and personal care products (PPCPs). There is a wide variety and vast quantity of PPCPs consumed by both humans and animals, and each has unique chemistry in terrestrial and aquatic environments. As such, not all have been assessed for their effects on soil, water, and air quality. The US Environmental Protection Agency (EPA) has surveyed sewage sludge from wastewater treatment plants across the US to assess levels of various PPCPs present. The major inputs of heavy metals (e.g. lead, cadmium, arsenic, mercury) into agricultural systems are fertilizers, organic wastes such as manures, and industrial byproduct wastes. Inorganic fertilizers especially represent an important pathway for heavy metals to enter soils. Some farming techniques, such as irrigation, can lead to accumulation of selenium (Se) that occurs naturally in the soil, which can result in downstream water reservoirs containing concentrations of selenium that are toxic to wildlife, livestock, and humans. This process is known as the “Kesterson Effect,” eponymously named after the Kesterson Reservoir in the San Joaquin Valley (California, USA), which was declared a toxic waste dump in 1987. Heavy metals present in the environment can be taken up by plants, which can pose health risks to humans in the event of consuming affected plants | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Some metals are essential to plant growth, however an abundance can have adverse effects on plant health. Steel industry wastes, which are often recycled into fertilizers due to their high levels of zinc (essential to plant growth), can also include the following toxic metals: lead, arsenic, cadmium, chromium, and nickel. The most common toxic elements in this type of fertilizer are mercury, lead, and arsenic. These potentially harmful impurities can be removed during fertilizer production; however, this significantly increases cost of fertilizer. Highly pure fertilizers are widely available, and perhaps best known as the highly water-soluble fertilizers containing blue dyes. Fertilizers such as these are commonly used around households, such as Miracle-Gro. These highly water-soluble fertilizers are used in the plant nursery business and are available in larger packages at significantly less cost than retail quantities. There are also some inexpensive retail granular garden fertilizers made with high purity ingredients, limiting production. Agriculture contributes greatly to soil erosion and sediment deposition through intensive management or inefficient land cover. It is estimated that agricultural land degradation is leading to an irreversible decline in fertility on about 6 million ha of fertile land each year. The accumulation of sediments (i.e. sedimentation) in runoff water affects water quality in various ways | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Sedimentation can decrease the transport capacity of ditches, streams, rivers, and navigation channels. It can also limit the amount of light penetrating the water, which affects aquatic biota. The resulting turbidity from sedimentation can interfere with feeding habits of fishes, affecting population dynamics. Sedimentation also affects the transport and accumulation of pollutants, including phosphorus and various pesticides. Natural soil biogeochemical processes result in the emission of various greenhouse gases, including nitrous oxide. Agricultural management practices can affect emission levels. For example, tillage levels have also been shown to affect nitrous oxide emissions. The United Nations Food and Agriculture Organization (FAO) predicted that 18% of anthropogenic greenhouse gases come directly or indirectly from the world’s livestock. This report also suggested that the emissions from livestock were greater than that of the transportation sector. While livestock do currently play a role in producing greenhouse gas emissions, the estimates have been argued to be a misrepresentation. While the FAO used a life cycle assessment of animal agriculture (i.e. all aspects including emissions from growing crops for feed, transportation to slaughter, etc.), they did not apply the same assessment for the transportation sector. A PNAS model showed that even if animals were completely removed from U.S. agriculture and diets, U.S. GHG emissions would be decreased by 2 | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution 6% only (or 28% of agricultural GHG emissions). This is because of the need replace animal manures by fertilizers and to replace also other animal coproducts, and because livestock now use human-inedible food and fiber processing byproducts. Moreover, people would suffer from a greater number of deficiencies in essential nutrients although they would get a greater excess of energy, possibly leading to greater obesity. Biopesticides are pesticides derived from natural materials (animals, plants, microorganisms, certain minerals). As an alternative to traditional pesticides, biopesticides can reduce overall agricultural pollution because they are safe to handle, usually do not strongly affect beneficial invertebrates or vertebrates, and have a short residual time. Some concerns exist that biopesticides may have negative impacts on populations of nontarget species, however. In the United States, biopesticides are regulated by EPA. Because biopesticides are less harmful and have fewer environmental effects than other pesticides, the agency does not require as much data to register their use. Many biopesticides are permitted under the National Organic Program, United States Department of Agriculture, standards for organic crop production. The increasing globalization of agriculture has resulted in the accidental transport of pests, weeds, and diseases to novel ranges. If they establish, they become an invasive species that can impact populations of native species and threaten agricultural production | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution For example, the transport of bumble bees reared in Europe and shipped to the United States and/or Canada for use as commercial pollinators has led to the introduction of an Old World parasite to the New World. This introduction may play a role in recent native bumble bee declines in North America. Agriculturally introduced species can also hybridize with native species resulting in a decline in genetic biodiversity and threaten agricultural production. Habitat disturbance (ecology) associated with farming practices themselves can also facilitate the establishment of these introduced organisms. Contaminated machinery, livestock and fodder, and contaminated crop or pasture seed can also lead to the spread of weeds. Quarantines (see biosecurity )are one way in which prevention of the spread of invasive species can be regulated at the policy level. A quarantine is a legal instrument that restricts the movement of infested material from areas where an invasive species is present to areas in which it is absent. The World Trade Organization has international regulations concerning the quarantine of pests and diseases under the Agreement on the Application of Sanitary and Phytosanitary Measures. Individual countries often have their own quarantine regulations. In the United States, for example, the United States Department of Agriculture/Animal and Plant Health Inspection Service (USDA/APHIS) administers domestic (within the United States) and foreign (importations from outside the United States) quarantines | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution These quarantines are enforced by inspectors at state borders and ports of entry. The use of biological pest control agents, or using predators, parasitoids, parasites, and pathogens to control agricultural pests, has the potential to reduce agricultural pollution associated with other pest control techniques, such as pesticide use. The merits of introducing non-native biocontrol agents have been widely debated, however. Once released, the introduction of a biocontrol agent can be irreversible. Potential ecological issues could include the dispersal from agricultural habitats into natural environments, and host-switching or adapting to utilize a native species. In addition, predicting the interaction outcomes in complex ecosystems and potential ecological impacts prior to release can be difficult. One example of a biocontrol program that resulted in ecological damage occurred in North America, where a parasitoid of butterflies was introduced to control gypsy moth and browntail moth. This parasitoid is capable of utilizing many butterfly host species, and likely resulted in the decline and extirpation of several native silk moth species. International exploration for potential biocontrol agents is aided by agencies such as the European Biological Control Laboratory, the United States Department of Agriculture/Agricultural Research Service (USDA/ARS), the Commonwealth Institute of Biological Control, and the International Organization for Biological Control of Noxious Plants and Animals | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution In order to prevent agricultural pollution, quarantine and extensive research on the organism’s potential efficacy and ecological impacts are required prior to introduction. If approved, attempts are made to colonize and disperse the biocontrol agent in appropriate agricultural settings. Continual evaluations on their efficacy are conducted. GMO crops can, however, result in genetic contamination of native plant species through hybridization. This could lead to increased weediness of the plant or the extinction of the native species. In addition, the transgenic plant itself may become a weed if the modification improves its fitness in a given environment. There are also concerns that non-target organisms, such as pollinators and natural enemies, could be poisoned by accidental ingestion of Bt-producing plants. A recent study testing the effects of Bt corn pollen dusting nearby milkweed plants on larval feeding of the monarch butterfly found that the threat to populations of the monarch was low. The use of GMO crop plants engineered for herbicide resistance can also indirectly increase the amount of agricultural pollution associated with herbicide use. For example, the increased use of herbicide in herbicide-resistant corn fields in the mid-western United States is decreasing the amount of milkweeds available for monarch butterfly larvae. Regulation of the release of genetic modified organisms vary based on the type of organism and the country concerned | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution While there may be some concerns regarding the use of GM products, it may also be the solution to some of the existing animal agriculture pollution issues. One of the main sources of pollution, particularly vitamin and mineral drift in soils, comes from a lack of digestive efficiency in animals. By improving digestive efficiency, it is possible to minimize both the cost of animal production and the environmental damage. One successful example of this technology and its potential application is the Enviropig. The Enviropig is a genetically modified Yorkshire pig that expresses phytase in its saliva. Grains, such as corn and wheat, have phosphorus that is bound in a naturally indigestible form known as phytic acid. Phosphorus, an essential nutrient for pigs, is then added to the diet, since it can not be broken down in the pigs digestive tract. As a result, nearly all of the phosphorus naturally found in the grain is wasted in the feces, and can contribute to elevated levels in the soil. Phytase is an enzyme that is able to break down the otherwise indigestible phytic acid, making it available to the pig. The ability of the Enviropig to digest the phosphorus from the grains eliminates the waste of that natural phosphorus (20-60% reduction), while also eliminating the need to supplement the nutrient in feed. One of the main contributors to air, soil and water pollution is animal waste | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution According to a 2005 report by the USDA, more than 335 million tons of "dry matter" waste (the waste after water is removed) is produced annually on farms in the United States. Animal feeding operations produce about 100 times more manure than the amount of human sewage sludge processed in US municipal waste water plants each year. Diffuse source pollution from agricultural fertilizers is more difficult to trace, monitor and control. High nitrate concentrations are found in groundwater and may reach 50 mg/litre (the EU Directive limit). In ditches and river courses, nutrient pollution from fertilizers causes eutrophication. This is worse in winter, after autumn ploughing has released a surge of nitrates; winter rainfall is heavier increasing runoff and leaching, and there is lower plant uptake. EPA suggests that one dairy farm with 2,500 cows produces as much waste as a city with around 411,000 residents. The US National Research Council has identified odors as the most significant animal emission problem at the local level. Different animal systems have adopted several waste management procedures to deal with the large amount of waste produced annually. The advantages of manure treatment are a reduction in the amount of manure that needs to be transported and applied to crops, as well as reduced soil compaction. Nutrients are reduced as well, meaning that less cropland is needed for manure to be spread upon | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Manure treatment can also reduce the risk of human health and biosecurity risks by reducing the amount of pathogens present in manure. Undiluted animal manure or slurry is one hundred times more concentrated than domestic sewage, and can carry an intestinal parasite, "Cryptosporidium," which is difficult to detect but can be passed to humans. Silage liquor (from fermented wet grass) is even stronger than slurry, with a low pH and very high biological oxygen demand. With a low pH, silage liquor can be highly corrosive; it can attack synthetic materials, causing damage to storage equipment, and leading to accidental spillage. All of these advantages can be optimized by using the right manure management system on the right farm based on the resources that are available. Composting is a solid manure management system that relies on solid manure from bedded pack pens, or the solids from a liquid manure separator. There are two methods of composting, active and passive. Manure is churned periodically during active composting, whereas in passive composting it is not. Passive composting has been found to have lower green house gas emissions due to incomplete decomposition and lower gas diffusion rates. Manure can be mechanically separated into a solid and liquid portion for easier management. Liquids (4-8% dry matter) can be used easily in pump systems for convenient spread over crops and the solid fraction (15-30% dry matter) can be used as stall bedding, spread on crops, composted or exported | https://en.wikipedia.org/wiki?curid=23589344 |
Agricultural pollution Anaerobic digestion is the biological treatment of liquid animal waste using bacteria in an area absent of air, which promotes the decomposition of organic solids. Hot water is used to heat the waste in order to increase the rate of biogas production. The remaining liquid is nutrient rich and can be used on fields as a fertilizer and methane gas that can be burned directly on the biogas stove or in an engine generator to produce electricity and heat. Methane is about 20 times more potent as a greenhouse gas than carbon dioxide, which has significant negative environmental effects if not controlled properly. Anaerobic treatment of waste is the best method for controlling the odor associated with manure management. Biological treatment lagoons also use anaerobic digestion to break down solids, but at a much slower rate. Lagoons are kept at ambient temperatures as opposed to the heated digestion tanks. Lagoons require large land areas and high dilution volumes to work properly, so they do not work well in many climates in the northern United States. Lagoons also offer the benefit of reduced odor and biogas is made available for heat and electric power. Studies have demonstrated that GHG emissions are reduced using aerobic digestion systems. GHG emission reductions and credits can help compensate for the higher installation cost of cleaner aerobic technologies and facilitate producer adoption of environmentally superior technologies to replace current anaerobic lagoons. | https://en.wikipedia.org/wiki?curid=23589344 |
C18H32O2 The molecular formula CHO (Molar mass: 280.44 g/mol) may refer to: | https://en.wikipedia.org/wiki?curid=23593405 |
C18H30O2 The molecular formula CHO may refer to: | https://en.wikipedia.org/wiki?curid=23593450 |
C8H15NOS2 The molecular formula CHNOS (molar mass: 205.341 g/mol) may refer to: | https://en.wikipedia.org/wiki?curid=23593482 |
C10H19O6PS2 The molecular formula CHOPS (molar mass: 330.358 g/mol) may refer to: | https://en.wikipedia.org/wiki?curid=23593722 |
Borate buffered saline (abbreviated BBS) is a buffer used in some biochemical techniques to maintain the pH within a relatively narrow range. Borate buffers have an alkaline buffering capacity in the 8–10 range. Boric acid has a pK of 9.14 at 25°C. BBS has many uses because it is isotonic and has a strong bactericidal effect. It can be used to dilute substances and has applications in coating procedures. Additives such as [Polysorbate 20] and milk powder can be used to add to BBS's functionality as a washing buffer or blocking buffer. The following is a sample recipe for BBS: Adjust pH to pH 8.2 The simplest way to prepare a BBS solution is to use BBS tablets. They are formulated to give a ready to use borate buffered saline solution upon dissolution in 500 ml of deionized water. Concentration of borate and NaCl as well as the pH can vary, and the resulting solution would still be referred to as "borate buffered saline". Borate concentration (giving buffering capacity) can vary from 10 mM to 100 mM. As BBS is used to emulate physiological conditions (as in animal or human body), the pH value is slightly alkaline, ranging from 8.0–9.0. NaCl gives the isotonic (mostly used 150 mM NaCl corresponds to physiological conditions: 0.9% NaCl) salt concentration. | https://en.wikipedia.org/wiki?curid=23594484 |
Steven Zimmerman Professor Steven C. Zimmerman is an organic chemist on the faculty of the Department of Chemistry, University of Illinois at Urbana-Champaign. He was born in Chicago in 1957, the second son of the organic chemist Howard Zimmerman. He attended public schools in Madison, Wisconsin where he received a B.S. degree in 1979 working for Hans J. Reich. In 1983 he received a Ph.D. at Columbia University in New York City where he worked with Ronald Breslow on pyridoxamine enzyme analogs. After an NSF-NATO Postdoctoral Fellowship at the University of Cambridge with Sir Alan R. Battersby, he joined the faculty at the University of Illinois (1985). He was appointed the Roger Adams Professor of Chemistry at the University of Illinois at Urbana-Champaign in 2004, having previously held a William H. and Janet G. Lycan Professorship. Zimmerman served as the Head of the University of Illinois Department of Chemistry from 1999 to 2000 and 2005 to 2012. As Department Head he managed an academic staff of 115 full-time equivalents (FTE) with a State budget of $8.4 M and total expenditures of $26.7M, including federal research grants and contracts. He oversaw a $60M fundraising campaign and secured the three largest individual gifts (>$15M total) at the University of Illinois in academic year 2007 | https://en.wikipedia.org/wiki?curid=23595875 |
Steven Zimmerman He negotiated and oversaw a cooperative agreement to port the University of Illinois Department of Chemistry undergraduate curriculum to the Hanoi University of Science in Vietnam, increased standards for graduate enrollment, and increased the diversity of the faculty, staff, and student body. His early research was focused on molecular recognition, models of serine proteases, and topologically novel DNA intercalators. He and his coworkers pioneered the development of a new class of nonmacrocyclic molecular hosts called molecular tweezers, also called more recently, molecular clips. His current work focuses on dendrimers, including their supramolecular chemistry and the supramolecular chemistry of other polymers (supramolecular polymer chemistry). | https://en.wikipedia.org/wiki?curid=23595875 |
Optical contact bonding is a glueless process whereby two closely conformal surfaces are joined together, being held purely by intermolecular forces. Isaac Newton has been credited with the first description of conformal interaction observed through the interference phenomenon known as Newton's rings, though it was S. D. Poisson in 1823 who first described the optical characteristics of two identical surfaces in contact. It was not until the 19th century that objects were made of such precision that the binding phenomenon was observed. The clinging together was described as "wringing together", or as "ansprengen" in German. By 1900 optical contact bonding was being employed in the construction of optical prisms, and the following century saw further research into the phenomenon at the same time that ideas of inter-atom interactions were first being studied. Intermolecular forces such as Van der Waals forces, hydrogen bonds, and dipole-dipole interactions are typically not sufficiently strong to hold two apparently conformal rigid bodies together, since the forces drop off rapidly with distance, and the actual area in contact between the two bodies is small due to surface roughness and minor imperfections. However, if the bodies are conformal to an accuracy of better than 10 angstroms (1 nanometer), then a sufficient surface area is in close enough contact for the intermolecular interactions to have an observable real world physical manifestation—that is, the two objects stick together | https://en.wikipedia.org/wiki?curid=23596560 |
Optical contact bonding Such a condition requires a high degree of accuracy and surface smoothness, which is typically found in optical components, such as prisms. In addition to both surfaces' being practically conformal (in practice often completely flat), the surfaces must also be extremely clean and free from any small contamination that would prevent or weaken the bond—including grease films and specks of dust. For bonding to occur, the surfaces need only to be brought together; the intermolecular forces draw the bodies into the lowest energy conformation, and no pressure needs to be applied. Since the method requires no binder, balsam or glue, the physical properties of the bound object are the same as the objects joined. Typically, glues and binders are more heat sensitive or have undesirable properties compared to the actual bodies being joined. The use of optical contact bonding allows the production of a final product with properties as good as the bulk solid. This can include temperature and chemical resistances, spectral absorption properties and reduced contamination from bonding materials. Originally the process was confined to optical equipment such as prisms—the earliest examples being made around 1900. Later the scope of use was expanded to microelectronics and other miniaturised devices. | https://en.wikipedia.org/wiki?curid=23596560 |
Design II for Windows DESIGN II for Windows is a rigorous process simulator for chemical and hydrocarbon processes including refining, refrigeration, petrochemical, gas processing, gas treating, pipelines, fuel cells, ammonia, methanol and hydrogen facilities. In 1969 the DESIGN program was first offered on the University Computing Company (UCC) time sharing services. The DISTILL column program was merged into DESIGN to create DESIGN 2000 in 1975, and in 1984 – REFINE column and crude feeds program were merged into DESIGN 2000 to create DESIGN II. In 1991 the Windows user interface was added to DESIGN II and DESIGN II for Windows was born. WinSim Inc. has developed and marketed DESIGN II for Windows, a steady-state process simulator, since 1995 when the company purchased the rights to the program from ChemShare Corporation. Website: http://www.winsim.com/ | https://en.wikipedia.org/wiki?curid=23597565 |
Analytical and Bioanalytical Chemistry is a peer-reviewed scientific journal publishing research articles in the broad field of analytical and bioanalytical chemistry. Some of the subjects covered are the development of instruments for mass spectrometry, metallomics, ionics, and the analytical characterization of nano- and biomaterials. The journal was first published in 1862 under the name Fresenius’ Journal of Analytical Chemistry. In 2002 the journal was renamed to "Analytical and Bioanalytical Chemistry". "Analytical and Bioanalytical Chemistry" had a 2018 impact factor of 3.286, ranking it 18th out of 84 in the subject category "Chemistry, Analytical" and 21st out of 79 in "Biochemical Research Methods". The editors of the journal are A.J Baeumner H. Cui, G. Gauglitz, G. Hopfgartner, L. Mondello, M.C. Moreno-Bondi, D.C. Muddiman, S. Szunerits, Q. Qang and S.A. Wise. | https://en.wikipedia.org/wiki?curid=23603242 |
Bioanalysis is a sub-discipline of analytical chemistry covering the quantitative measurement of xenobiotics (drugs and their metabolites, and biological molecules in unnatural locations or concentrations) and biotics (macromolecules, proteins, DNA, large molecule drugs, metabolites) in biological systems. Many scientific endeavors are dependent upon accurate quantification of drugs and endogenous substances in biological samples; the focus of bioanalysis in the pharmaceutical industry is to provide a quantitative measure of the active drug and/or its metabolite(s) for the purpose of pharmacokinetics, toxicokinetics, bioequivalence and exposure–response (pharmacokinetics/pharmacodynamics studies). also applies to drugs used for illicit purposes, forensic investigations, anti-doping testing in sports, and environmental concerns. was traditionally thought of in terms of measuring small molecule drugs. However, the past twenty years has seen an increase in biopharmaceuticals (e.g. proteins and peptides), which have been developed to address many of the same diseases as small molecules. These larger biomolecules have presented their own unique challenges to quantification. The first studies measuring drugs in biological fluids were carried out to determine possible overdosing as part of the new science of forensic medicine/toxicology. Initially, nonspecific assays were applied to measuring drugs in biological fluids | https://en.wikipedia.org/wiki?curid=23604382 |
Bioanalysis These were unable to discriminate between the drug and its metabolites; for example, aspirin (circa 1900) and sulfonamides (developed in the 1930s) were quantified by the use of colorimetric assays. Antibiotics were quantified by their ability to inhibit bacterial growth. The 1930s also saw the rise of pharmacokinetics, and as such the desire for more specific assays. Modern drugs are more potent, which has required more sensitive bioanalytical assays to accurately and reliably determine these drugs at lower concentrations. This has driven improvements in technology and analytical methods. Some techniques commonly used in bioanalytical studies include: The most frequently used techniques are: liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) for 'small' molecules and enzyme-linked immunosorbent assay (ELISA) for macromolecules. The bioanalyst deals with complex biological samples containing the analyte alongside a diverse range of chemicals that can have an adverse impact on the accurate and precise quantification of the analyte. As such, a wide range of techniques are applied to extract the analyte from its matrix. These include: Bioanalytical laboratories often deal with large numbers of samples, for example resulting from clinical trials. As such, automated sample preparation methods and liquid-handling robots are commonly employed to increase efficiency and reduce costs. There are several national and international bioanalytical organisations active throughout the world | https://en.wikipedia.org/wiki?curid=23604382 |
Bioanalysis Often they are part of a bigger organisation, e.g. Bioanalytical Focus Group and Ligand Binding Assay Bioanalytical Focus Group, which are both within the American Association of Pharmaceutical Scientists (AAPS) and FABIAN, a working group of the Analytical Chemistry Section of the Royal Netherlands Chemical Society. The European Forum (EBF), on the other hand, is independent of any larger society or association. Hanover Search Partners based in San Diego, California is the leading recruitment firm in the Bioanalytical space and contracts with many of the world's leading Bioanalytical companies in recruiting the top executive and scientific talent worldwide. | https://en.wikipedia.org/wiki?curid=23604382 |
1,1-Dichloro-1-fluoroethane is a haloalkane with the formula . It is one of the three isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon family (HCFC). is mainly used as a refrigerant under the names R-141b or HCFC-141b. It is a non-flammable, colourless liquid in atmospheric conditions. The compound is very volatile and its smell has been described as "usually ethereal". | https://en.wikipedia.org/wiki?curid=23605014 |
Chloranil is a quinone with the molecular formula CClO. Also known as tetrachloro-1,4-benzoquinone, it is a yellow solid. Like the parent benzoquinone, chloranil is a planar molecule that functions as a mild oxidant. is produced by chlorination of phenol to give hexachlorocyclohexa-2,5-dien-1-one ("hexachlorophenol"). Hydrolysis of the dichloromethylene group in this dienone gives chloranil: Chloroanil serves as a hydrogen acceptor. It is more electrophilic than quinone itself. It is used for the aromatization reactions, such as the conversion of cyclohexadienes to the benzene derivatives. is used to test for free secondary amines. This test is useful for checking for the presence of proline derivatives. It is also a good test for the successful deprotection of a secondary amine. Secondary amines react with chloranil to give a brown/red/orange derivative, the colour depending on the amine. In these reactions, the amine displaces chloride from the ring of the quinone. It is a precursor to many dyes, such as pigment violet 23 and diaziquone (AZQ), a cancer chemotherapeutic agent. | https://en.wikipedia.org/wiki?curid=23606776 |
Ultrafiltered milk (UF milk), also known as diafiltered milk, is a subclassification of milk protein concentrate that is produced by passing milk under pressure through a thin, porous membrane to separate the components of milk according to their size. Specifically, ultra filtration allows the smaller lactose, water, mineral, and vitamin molecules to pass through the membrane, while the larger protein and fat molecule (key components for making cheese) are retained and concentrated. (Depending on the intended use of the UF milk product, the fat in whole milk may be removed before filtration.) The removal of water and lactose reduces the volume of milk, and thereby lowers its transportation and storage costs. Ultrafiltration makes cheese manufacturing more efficient. is also sold directly to consumers under brands like fairlife and Simply Smart, who tout its higher protein content, lower sugar content, and creamier taste. According to at least one publication, ultrafiltration and diafiltration are synonymous terms. | https://en.wikipedia.org/wiki?curid=23609445 |
List of veterinary drugs This article lists veterinary pharmaceutical drugs alphabetically by name. Many veterinary drugs have more than one name and, therefore, the same drug may be listed more than once. Abbreviations are used in the list as follows: | https://en.wikipedia.org/wiki?curid=23609968 |
Chemik Polski was the first Polish scientific journal of chemistry. It was published weekly, and later bi-weekly, in the years 1901-1918 by the Chemistry Section of the Warsaw Branch of the Russian Society for the Promotion of Industry and Commerce and covered all branches of theoretical and applied chemistry. The journal was published in Warsaw, initially by J. Leski, and from 1908 by Boleslaw Miklaszewski. The founder and editor in chief was Bronislaw Znatowicz. Contributors included Marie Curie and Wojciech Świętosławski. | https://en.wikipedia.org/wiki?curid=23612452 |
Chemiker Zeitung was a German scientific journal with publications on general and industrial chemistry. It was established in 1877, and it issued in Köthen. From 1932 onwards, it was named "Forschrittsbericht der Chemiker-Zeitung über die wichtigsten Gebiete der Chemie und chemischen Industrie" and in 1950 the name changed to "Deutsche Chemiker-Zeitschrift". Publication was suspended between 1945-1949. The journal was continued from 1959 to 1968 as the "Chemiker-Zeitung, Chemische Apparatur". In 1992, "Chemiker Zeitung" was merged with "Journal für praktische Chemie" (established in 1834). Since 2001, "Advanced Synthesis & Catalysis" (publisher: Wiley-VCH, Weinheim, Germany) integrated both "Chemiker Zeitung" and "Journal für praktische Chemie". | https://en.wikipedia.org/wiki?curid=23612500 |
Jahres-Bericht über die Fortschritte der chemischen Technologie für Fabrikanten, Chemiker, Pharmaceuten, Hütten- und Forstleute und Cameralisten is a German scientific journal on chemistry, pharmacy and metallurgy. The journal was published in Leipzig by Otto Wigand from 1855-1859. The journal continued from 1859-1912 under the name "Jahres-Bericht über die Fortschritte und Leistungen der chemischen Technologie und Technischen Chemie". | https://en.wikipedia.org/wiki?curid=23612550 |
Energy homeostasis In biology, energy homeostasis, or the homeostatic control of energy balance, is a biological process that involves the coordinated homeostatic regulation of food intake (energy inflow) and energy expenditure (energy outflow). The human brain, particularly the hypothalamus, plays a central role in regulating energy homeostasis and generating the sense of hunger by integrating a number of biochemical signals that transmit information about energy balance. Fifty percent of the energy from glucose metabolism is immediately converted to heat. is an important aspect of bioenergetics. In the US, biological energy is expressed using the energy unit Calorie with a capital C (i.e. a kilocalorie), which equals the energy needed to increase the temperature of 1 kilogram of water by 1 °C (about 4.18 kJ). Energy balance, through biosynthetic reactions, can be measured with the following equation: The first law of thermodynamics states that energy can be neither created nor destroyed. But energy can be converted from one form of energy to another. So, when a calorie of food energy is consumed, one of three particular effects occur within the body: a portion of that calorie may be stored as body fat, triglycerides, or glycogen, transferred to cells and converted to chemical energy in the form of adenosine triphosphate (ATP – a coenzyme) or related compounds, or dissipated as heat. Energy intake is measured by the amount of calories consumed from food and fluids | https://en.wikipedia.org/wiki?curid=23613099 |
Energy homeostasis Energy intake is modulated by hunger, which is primarily regulated by the hypothalamus, and choice, which is determined by the sets of brain structures that are responsible for stimulus control (i.e., operant conditioning and classical conditioning) and cognitive control of eating behavior. Hunger is regulated in part by the action of certain peptide hormones and neuropeptides (e.g., insulin, leptin, ghrelin, and neuropeptide Y, among others) in the hypothalamus. Energy expenditure is mainly a sum of internal heat produced and external work. The internal heat produced is, in turn, mainly a sum of basal metabolic rate (BMR) and the thermic effect of food. External work may be estimated by measuring the physical activity level (PAL). The Set-Point Theory, first introduced in 1953, postulated that each body has a preprogrammed fixed weight, with regulatory mechanisms to compensate. This theory was quickly adopted and used to explain failures in developing effective and sustained weight loss procedures. A 2019 systematic review of multiple weight change interventions on humans, including dieting, exercise and overeating, found systematic "energetic errors", the non-compensated loss or gain of calories, for all these procedures. This shows that the body cannot precisely compensate for errors in energy/calorie intake, contrary to what the Set-Point Theory hypothesizes, and potentially explaining both weight loss and weight gain such as obesity | https://en.wikipedia.org/wiki?curid=23613099 |
Energy homeostasis This review was conducted on short term studies, therefore such a mechanism cannot be excluded in the long term, as evidence is currently lacking on this timeframe. A positive balance is a result of "energy intake" being "higher" than what is consumed in external work and other bodily means of energy expenditure. The main preventable causes are: A positive balance results in energy being stored as fat and/or muscle, causing weight gain. In time, overweight and obesity may develop, with resultant complications. A negative balance is a result of energy intake being less than what is consumed in external work and other bodily means of energy expenditure. The main cause is "undereating" due to a medical condition such as decreased appetite, anorexia nervosa, digestive disease, or due to some circumstance such as fasting or lack of access to food. Hyperthyroidism can also be a cause. Normal energy requirement, and therefore normal energy intake, depends mainly on age, sex and physical activity level (PAL). The Food and Agriculture Organization (FAO) of the United Nations has compiled a detailed report on human energy requirements: Human energy requirements (Rome, 17–24 October 2001) An older but commonly used and fairly accurate method is the Harris-Benedict equation | https://en.wikipedia.org/wiki?curid=23613099 |
Energy homeostasis Yet, there are currently ongoing studies to show if calorie restriction to below normal values have beneficial effects, and even though they are showing positive indications in primates it is still not certain if calorie restriction has a positive effect on longevity for primates and humans. Calorie restriction may be viewed as attaining energy balance at a lower intake and expenditure, and is, in this sense, not generally an energy imbalance, except for an initial imbalance where decreased expenditure hasn't yet matched the decreased intake. There has been controversy over energy-balance messages that downplay energy intake being promoted by food industry groups. | https://en.wikipedia.org/wiki?curid=23613099 |
Catalysis Letters is a peer-reviewed scientific journal covering research on catalysis in a wide range of sub-disciplines such as homogeneous, heterogeneous and enzymatic catalysis. It was previously published by Baltzer Science Publishers, which was then sold to Wolters Kluwer (which later became Springer Science+Business Media). | https://en.wikipedia.org/wiki?curid=23614643 |
Silicon (journal) Silicon is a peer-reviewed scientific journal published by Springer and founded in 2009 by editor in chief Stephen Clarson. It deals with all aspects of silicon. Published research involves materials biology, materials physics, materials chemistry, materials engineering, and environmental science. The journal caters to chemists, physicists, engineers, biologists, and environmental scientists. | https://en.wikipedia.org/wiki?curid=23614788 |
Enantiopure drug An enantiopure drug is a pharmaceutical that is available in one specific enantiomeric form. Most biological molecules (proteins, sugars, etc.) are present in only one of many chiral forms, so different enantiomers of a chiral drug molecule bind differently (or not at all) to target receptors. One enantiomer of a drug may have a desired beneficial effect while the other may cause serious and undesired side effects, or sometimes even beneficial but entirely different effects. Advances in industrial chemical processes have made it economical for pharmaceutical manufacturers to take drugs that were originally marketed as a racemic mixture and market the individual enantiomers, either by specifically manufacturing the desired enantiomer or by resolving a racemic mixture. On a case-by-case basis, the U.S. Food and Drug Administration (FDA) has allowed single enantiomers of certain drugs to be marketed under a different name than the racemic mixture. Also case-by-case, the United States Patent Office has granted patents for single enantiomers of certain drugs. The regulatory review for marketing approval (safety and efficacy) and for patenting (proprietary rights) is independent, and differs country by country. "Selectivity" is a very important part of organic synthesis. In scientific papers regarding synthesis, selectivity is often listed in data tables alongside percent yield and other reaction conditions | https://en.wikipedia.org/wiki?curid=23616040 |
Enantiopure drug While selectivity is deemed important in scientific literature, it has been challenging to effectively implement selectivity in drug development and production. A major issue with selectivity in pharmaceuticals is that a large percentage of drug syntheses by nature are not selective reactions, racemic mixtures are formed as the products. Separating racemic mixtures into their respective enantiomers takes extra time, money, and energy. One way to separate enantiomers is to chemically convert them into species that can be separated: diastereomers. Diastereomers, unlike enantiomers, have entirely different physical properties—boiling points, melting points, NMR shifts, solubilities—and they can be separated by conventional means such as chromatography or recrystallization. This is a whole extra step in the synthesis process and not desirable from a manufacturing standpoint. As a result, a number of pharmaceuticals are synthesized and marketed as a racemic mixture of enantiomers in cases where the less-effective enantiomer is benign. However, by identifying and specifically purifying the enantiomer which effectively binds to its respective binding site in the body, less of the drug would be needed to achieve the desired effect. According to the FDA, the stereoisomeric composition of a chiral drug should be known, and its effects should be well-characterized from pharmacologic, toxicologic, and clinical standpoints | https://en.wikipedia.org/wiki?curid=23616040 |
Enantiopure drug In order to profile the different stereoisomers of enantiopure drugs, manufacturers are urged to develop quantitative assays for individual enantiomers in "in vivo" samples early in the development stage. Ideally, the main pharmacologic activities of the isomers should be compared in "in vitro" systems in animals. During instances when toxic findings are present beyond the natural extensions of the pharmacologic effects of the drug, toxicologic evaluation of the individual isomers in question must be completed. When drugs are covered under patent protection, only the pharmaceutical company that holds the patent is allowed to manufacture, market, and eventually profit from them. The lifetime of the patent varies between countries and also between drugs; in the United States, most drug patents last about twenty years. Once the patent has expired, the drug can be manufactured and sold by other companies - at which point, it is referred to as a generic drug. Its availability on the market as a generic drug removes the monopoly of the patent holder, thereby encouraging competition and causing a significant drop in drug prices, which ensures that life-saving and important drugs reach the general population at fair prices. However, the company holding the initial patent may get a new patent by forming a new version of the drug that is significantly changed compared to the original compound | https://en.wikipedia.org/wiki?curid=23616040 |
Enantiopure drug Patentability of different isomers has been controversial over the past ten years and there have been a number of related legal issues. In making their determinations, courts have looked at factors including: (i) Whether the racemate was known in the prior art. (ii) The difficulty in resolving the enantiomers. (iii) The stereoselectivity of the relevant receptor. (iv) Other secondary considerations of non-obviousness such as commercial success, unexpected results, and satisfaction of long-felt needs in the art. The decisions made regarding these issues have varied and there is no clear answer to the legality of patenting stereoisomers. These issues have been resolved on a case-by-case basis. With the number of current pharmaceuticals currently being marketed as racemic mixtures, it is likely that patentability will continue to be debated in the near future. The following table lists pharmaceuticals that have been available in both racemic and single-enantiomer form. The following are cases where the individual enantiomers have markedly different effects: | https://en.wikipedia.org/wiki?curid=23616040 |
Return flow is surface and subsurface water that leaves the field following application of irrigation water. While irrigation return flows are point sources, in the United States they are expressly exempted from discharge permit requirements under the Clean Water Act. Return flows generally return to the irrigation centre after a period of about three to four weeks; due to this, the farmers usually need to pour bleach into the water to clean it of any organisms that have entered the stream. If this is not taken care of, diseases such as typhoid or cholera could enter the irrigation and pose a risk of epidemic disease to surrounding towns and cities. The return flows in irrigation is nearly 50% of the water supplied in silty clay soil type in tropical countries. The salinity of the return flow water increases with decrease in % of return flow quantity. Rest of the water supplied to irrigation evaporates to atmosphere due to evapotranspiration. When ground water is extracted for irrigation and other uses, most of the return flows seep back into the ground instead of joining the nearby surface stream. When ground water is used in excess of recharge from rainfall/precipitation, the quality of groundwater deteriorates over a period of time and becomes unfit for irrigation use. | https://en.wikipedia.org/wiki?curid=23616088 |
C8H16 The molecular formula CH may refer to: | https://en.wikipedia.org/wiki?curid=23618338 |
C8H18 The molecular formula CH may refer to: | https://en.wikipedia.org/wiki?curid=23618390 |
Trimethylpentane may refer to: | https://en.wikipedia.org/wiki?curid=23618426 |
Nutrient pollution Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients. It is a primary cause of eutrophication of surface waters, in which excess nutrients, usually nitrogen or phosphorus, stimulate algal growth. Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots, and emissions from combustion. Excess nutrients have been summarized as potentially leading to: In a 2011 United States Environmental Protection Agency (EPA) report, the agency's Science Advisory Board succinctly stated: “Excess reactive nitrogen compounds in the environment are associated with many large-scale environmental concerns, including eutrophication of surface waters, toxic algae blooms, hypoxia, acid rain, nitrogen saturation in forests, and global warming.” Use of synthetic fertilizers, burning of fossil fuels, and agricultural animal production, especially concentrated animal feeding operations (CAFO), have added large quantities of reactive nitrogen to the biosphere. Phosphorus pollution is caused by excessive use of fertilizers and manure, particularly when compounded by soil erosion. Phosphorus is also discharged by municipal sewage treatment plants and some industries. The principal source(s) of nutrient pollution in an individual watershed depend on the prevailing land uses | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution The sources may be point sources, nonpoint sources, or both: from some air pollution sources may occur independently of the local land uses, due to long-range transport of air pollutants from distant sources. Agricultural nonpoint source (NPS) pollution is the largest source of water quality impairments throughout the U.S., based on surveys by state environmental agencies. NPS pollution is not subject to discharge permits under the federal Clean Water Act (CWA). EPA and states have used grants, partnerships and demonstration projects to create incentives for farmers to adjust their practices and reduce surface runoff. Many point source dischargers in the U.S., while not necessarily the largest sources of nutrients in their respective watersheds, are required to comply with nutrient effluent limitations in their permits, which are issued through the National Pollutant Discharge Elimination System (NPDES), pursuant to the CWA. Some large municipal sewage treatment plants, such as the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C. have installed biological nutrient removal (BNR) systems to comply with regulatory requirements. Other municipalities have made adjustments to the operational practices of their existing secondary treatment systems to control nutrients. Discharges from large livestock facilities (CAFO) are also regulated by NPDES permits | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution Surface runoff from farm fields, the principal source of nutrients in many watersheds, is classified as NPS pollution and is not regulated by NPDES permits. A Total Maximum Daily Load (TMDL) is a regulatory plan that prescribes the maximum amount of a pollutant (including nutrients) that a body of water can receive while still meeting CWA water quality standards. Specifically, Section 303 of the Act requires each state to generate a TMDL report for each body of water impaired by pollutants. TMDL reports identify pollutant levels and strategies to accomplish pollutant reduction goals. EPA has described TMDLs as establishing a "pollutant budget" with allocations to each of the pollutant's sources. For many coastal water bodies, the main pollutant issue is excess nutrients, also termed "nutrient over-enrichment." A TMDL can prescribe the minimum level of dissolved oxygen (DO) available in a body of water, which is directly related to nutrient levels. ("See" Aquatic Hypoxia.) In 2010, 18 percent of TMDLs nationwide were related to nutrient levels including organic enrichment/oxygen depletion, noxious plants, algal growth, and ammonia. TMDLs identify all point source and nonpoint source pollutants within a watershed. To implement TMDLs with point sources, wasteload allocations are incorporated into their NPDES permits. NPS discharges are generally in a voluntary compliance scenario | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution In Long Island Sound, the TMDL development process enabled the Connecticut Department of Energy and Environmental Protection and the New York State Department of Environmental Conservation to incorporate a 58.5 percent nitrogen reduction target into a regulatory and legal framework. Innovative solutions have been conceived to deal with nutrient pollution in aquatic systems by altering or enhancing natural processes to shift nutrient effects away from detrimental ecological impacts. Nutrient remediation is a form of environmental remediation, but concerns only biologically active nutrients such as nitrogen and phosphorus. “Remediation” refers to the removal of pollution or contaminants, generally for the protection of human health. In environmental remediation nutrient removal technologies include biofiltration, which uses living material to capture and biologically degrade pollutants. Examples include green belts, riparian areas, natural and constructed wetlands, and treatment ponds. These areas most commonly capture anthropogenic discharges such as wastewater, stormwater runoff, or sewage treatment, for land reclamation after mining, refinery activity, or land development. Biofiltration utilizes biological assimilation to capture, absorb, and eventually incorporate the pollutants (including nutrients) into living tissue. Another form of nutrient removal is bioremediation, which uses microorganisms to remove pollutants | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution Bioremediation can occur on its own as natural attenuation or intrinsic bioremediation or can be encouraged by the addition of fertilizers, a strategy called biostimulation. Nutrient bioextraction is bioremediation involving cultured plants and animals. Nutrient bioextraction or bioharvesting is the practice of farming and harvesting shellfish and seaweed for the purpose of removing nitrogen and other nutrients from natural water bodies. It has been suggested that nitrogen removal by oyster reefs could generate net benefits for sources facing nitrogen emission restrictions, similar to other nutrient trading scenarios. Specifically, if oysters maintain nitrogen levels in estuaries below thresholds that would lead to the imposition of emission limits, oysters effectively save the sources the compliance costs they otherwise would incur. Several studies have shown that oysters and mussels have the capacity to dramatically impact nitrogen levels in estuaries. Additionally, studies have demonstrated seaweed's potential to improve nitrogen levels. The basic requirements for states to develop nutrient criteria and standards were mandated in the 1972 Clean Water Act. Implementing this water quality program has been a major scientific, technical and resource-intensive challenge for both EPA and the states, and development is continuing well into the 21st century. EPA published a wastewater management regulation in 1978 to begin to address the national nitrogen pollution problem, which had been increasing for decades | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution In 1998, the agency published a "National Nutrient Strategy" with a focus on developing nutrient criteria. Between 2000 and 2010 EPA published federal-level nutrient criteria for rivers/streams, lakes/reservoirs, estuaries and wetlands; and related guidance. "Ecoregional" nutrient criteria for 14 ecoregions across the U.S. were included in these publications. While states may directly adopt the EPA-published criteria, in many cases the states need to modfiy the criteria to reflect site-specific conditions. In 2004, EPA stated its expectations for numeric criteria (as opposed to less-specific narrative criteria) for total nitrogen (TN), total phosphorus (TP), chlorophyll a(chl-a), and clarity, and established "mutually-agreed upon plans" for state criteria development. In 2007, the agency stated that progress among the states on developing nutrient criteria had been uneven. EPA reiterated its expectations for numeric criteria and promised its support for state efforts to develop their own criteria. In 2008 EPA published a progress report on state efforts to develop nutrient standards. A majority of states had not developed numeric nutrient criteria for rivers and streams; lakes and reservoirs; wetlands and estuaries (for those states that have estuaries). In the same year, EPA also established a Nutrient Innovations Task Group (NITG), composed of state and EPA experts, to monitor and evaluate the progress of reducing nutrient pollution | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution In 2009 the NTIG issued a report, "An Urgent Call to Action," expressing concern that water quality continued to deteriorate nationwide due to increasing nutrient pollution, and recommending more vigorous development of nutrient standards by the states. In 2011 EPA reiterated the need for states to fully develop their nutrient standards, noting that drinking water violations for nitrates had doubled in eight years, that half of all streams nationwide had medium to high levels of nitrogen and phosphorus, and harmful algal blooms were increasing. The agency set out a framework for states to develop priorities and watershed-level goals for reductions of nutrients. After the EPA had introduced watershed-based NPDES permitting in 2007, interest in nutrient removal and achieving regional TMDLs led to the development of nutrient trading schemes. Nutrient trading is a type of water quality trading, a market-based policy instrument used to improve or maintain water quality. Water quality trading arose around 2005 and is based on the fact that different pollution sources in a watershed can face very different costs to control the same pollutant. Water quality trading involves the voluntary exchange of pollution reduction credits from sources with low costs of pollution control to those with high costs of pollution control, and the same principles apply to nutrient water quality trading. The underlying principle is “polluter pays”, usually linked with a regulatory requirement for participating in the trading program | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution A 2013 Forest Trends report summarized water quality trading programs and found three main types of funders: beneficiaries of watershed protection, polluters compensating for their impacts and "public good payers" that may not directly benefit, but fund the pollution reduction credits on behalf of a government or NGO. As of 2013, payments were overwhelmingly initiated by public good payers like governments and NGOs. Nutrient source apportionment is used to estimate the nutrient load from various sectors entering water bodies, following attenuation or treatment. Agriculture is typically the principal source of nitrogen in water bodies in Europe, whereas in many countries households and industries tend to be the dominant contributors of phosphorus. Where water quality is impacted by excess nutrients, load source apportionment models can support the proportional and pragmatic management of water resources by identifying the pollution sources. There are two broad approaches to load apportionment modelling, (i) load-orientated approaches which apportion origin based on in-stream monitoring data and (ii) source-orientated approaches where amounts of diffuse, or nonpoint source pollution, emissions are calculated using models typically based on export coefficients from catchments with similar characteristics | https://en.wikipedia.org/wiki?curid=23618578 |
Nutrient pollution For example, the Source Load Apportionment Model (SLAM) takes the latter approach, estimating the relative contribution of sources of nitrogen and phosphorus to surface waters in Irish catchments without in-stream monitoring data by integrating information on point discharges (urban wastewater, industry and septic tank systems), diffuse sources (pasture, arable, forestry, etc.), and catchment data, including hydrogeological characteristics. | https://en.wikipedia.org/wiki?curid=23618578 |
Minor Use Animal Drug Program The (or National Research Support Project 7) is the counterpart for animals of the IR-4 Minor Crop Pest Management Program. The program targets development of therapeutic drugs for minor species, such as small ruminants and aquatic species, plus support for drugs for minor use within major species. It is carried out in partnership with the Food and Drug Administration’s (FDA) Center for Veterinary Medicine. | https://en.wikipedia.org/wiki?curid=23618627 |
W. E. S. Turner William Ernest Stephen Turner (22 September 1881 – 27 October 1963) was a British chemist and pioneer of scientific glass technology. Turner was born in Wednesbury, Staffordshire on 22 September 1881. He went to King Edward VI Grammar School, Five Ways, Birmingham, and achieved a BSc (1902) and MSc (1904) in chemistry at the University of Birmingham. He married Mary Isobell Marshall (died 1939) and they had 4 children. In 1904, he joined the University College of Sheffield as a lecturer, and, in 1915, established the Department of Glass Manufacture, becoming in 1916 the Department of Glass Technology. He remained as its head until his retirement in 1945. In 1943, he married Helen Nairn Munro, an artist noted for her glass engraving, and a teacher of glass decoration at the Edinburgh College of Art. She was provided with a blue dress and shoes in glass fibre cloth (which was then an unusual industrial material). This has been selected as one of the items in the BBC's A History of the World in 100 Objects. The same year, he established a collection of historical and modern glass which became the Turner Museum of Glass from his extensive collection, and the wedding dress is on display there. He died on 27 October 1963. From 1904 to 1914, he published 21 papers on physical chemistry, mainly on molecular weights in solution. However, the bulk of his work from 1917 to 1954 was on the chemistry and technology of glass | https://en.wikipedia.org/wiki?curid=23619441 |
W. E. S. Turner Following his retirement, he produced an extensive series on the history of glass technology and on glass in archeology. Apart from this, in 1909, he wrote a series of articles in the Sheffield Daily Telegraph about the scientist in industry, in which cooperation with universities was urged. His early career was strictly academic, largely dealing with the associations of molecules in the liquid state. However, as his articles in the local newspaper showed, he was interested in the application of science to practical industrial problems, and this became the main theme of his work. The beginning of the First World War cut off metallurgical supplies from Germany and Austria, and Turner proposed that the University should help British industry. The work in metallurgy led to enquiries about glass, and in 1915 Turner produced a 'Report on the glass industry of Yorkshire', noting that this was largely unscientific and rule of thumb in nature. He thereby persuaded the University to set up a Department of Glass Manufacture in 1915 for research and teaching where he remained for the rest of his career, becoming internationally known. The main thrust of his research was on a fundamental understanding of the relationship between the chemical composition and the working properties of glasses. In 1916, he founded the Society of Glass Technology, becoming its first secretary. It published a Journal, which he edited until 1951. He was also involved in the formation of the International Commission on Glass | https://en.wikipedia.org/wiki?curid=23619441 |
W. E. S. Turner Turner initially taught physical chemistry, and in 1905 started specific courses for metallurgists. This involvement led him to become President of the Sheffield Society of Applied Metallurgy in 1914. In 1915, the Department of Glass Manufacture began an outreach programme, providing short courses to industry in Mexborough, Barnsley, Castleford and Knottingley in addition to Saturday classes in Sheffield. These were extended to glass making centres in Derby, Alloa, Glasgow and London. From 1917, full-time day students entered for what became a Bachelor of Technical Science degree. During the Second World War, Turner and other staff of the department provided technical lectures to industries such as those making glass electronic vacuum tubes. He was appointed an Officer of the Order of the British Empire in the 1919 New Year Honours for application of science to the glass industry, and in 1938 was appointed a Fellow of the Royal Society. He was the only person outside Germany to receive the Otto Schott Medal. | https://en.wikipedia.org/wiki?curid=23619441 |
Indium-111 WBC scan The indium white blood cell scan, is a nuclear medicine procedure in which white blood cells (mostly neutrophils) are removed from the patient, tagged with the radioisotope Indium-111, and then injected intravenously into the patient. The tagged leukocytes subsequently localize to areas of relatively new infection. The study is particularly helpful in differentiating conditions such as osteomyelitis from decubitus ulcers for assessment of route and duration of antibiotic therapy. In imaging of infections, the gallium scan has a sensitivity advantage over the indium white blood cell scan in imaging osteomyelitis (bone infection) of the spine, lung infections and inflammation, and in detecting chronic infections. In part, this is because gallium binds to neutrophil membranes, even after neutrophil death, whereas localization of neutrophils labeled with indium requires them to be in relatively good functional order. However, indium leukocyte imaging is better at localizing acute (i.e., new) infections, where live neutrophils are still rapidly and actively localizing to the infection, for imaging for osteomyelitis that does not involve the spine, and for locating abdominal and pelvic infections. Both the gallium scan and indium-111 white blood cell imaging may be used to image fever of unknown origin (elevated temperature without an explanation) | https://en.wikipedia.org/wiki?curid=23624457 |
Indium-111 WBC scan However, the indium leukocyte scan will localize only to the approximately 25% of such cases which are caused by acute infections, while gallium is more broadly sensitive, localizing to other sources of fever, such as chronic infections and tumors. Gallium may be a better choice for spleen study because gallium does not normally accumulate in the spleen. | https://en.wikipedia.org/wiki?curid=23624457 |
Electrofiltration is a method that combines membrane filtration and electrophoresis in a dead-end process. is regarded as an appropriate technique for concentration and fractionation of biopolymers. The film formation on the filter membrane which hinders filtration can be minimized or completely avoided by the application of electric field, improving filtration’s performance and increasing selectivity in case of fractionation. This approach reduces significantly the expenses for downstream processing in bioprocesses. is a technique for separation and concentration of colloidal substances – for instance biopolymers. The principle of electrofiltration is based on overlaying electric field on a standard dead-end filtration. Thus the created polarity facilitates electrophoretic force which is opposite to the resistance force of the filtrate flow and directs the charged biopolymers. This provides extreme decrease in the film formation on the micro- or ultra-filtration membranes and the reduction of filtration time from several hours by standard filtration to a few minutes by electrofiltration. In comparison to cross-flow filtration electrofiltration exhibits not only increased permeate flow but also guarantees reduced shear force stress which qualifies it as particularly mild technique for separation of biopolymers that are usually unstable | https://en.wikipedia.org/wiki?curid=23627434 |
Electrofiltration The promising application in purification of biotechnological products is based on the fact that biopolymers are difficult for filtration but on the other hand they are usually charged as a result of the presence of amino and carboxyl groups. The objective of electrofiltration is to prevent the formation of filter cake and to improve the filtration kinetic of products difficult to filtrate. The electrophoresis of the particles and the electro-osmosis become essential when the filtration process is overlaid with electric field. By electrofiltration the conventional filtration is overlaid with an electric field (DC) which works parallel with the filtrate’s flow direction. When the electrophoretic force "F", oppositely directed to flow, overruns the hydrodynamic resistance force "F", the charged particles migrate from the filter medium, thus reducing significantly the thickness of the filter cake on the membrane. When the solid particles, subject to separation, are negatively charged they migrate towards the anode (positive pole) and deposit on the filter cloth situated there. As a result, on the cathode side’s membrane (negative pole) there is only a very thin film allowing nearly the whole filtrate to efflux through this membrane. Figure 1 presents schematic description of electrofiltration chamber with flushing electrodes. For the flushing circulation a buffer solution is used. This approach has been patented. The hydrodynamic resistance force is evaluated following the Stokes’ law | https://en.wikipedia.org/wiki?curid=23627434 |
Electrofiltration The electrophoretic force is evaluated following the Coulomb’s law. In these equations "r" presents the hydrodynamic radius of the colloids, formula_3 – the speed of electrophoretic migration, formula_4 – the dynamic viscosity of the solutions, formula_5 – dielectric constant in vacuum, formula_6 is water’s relative dielectric constant at 298 K, formula_7 is the zeta potential, "E" is the electric field. The hydrodynamic radius is the sum of particles’ radiuses and the stationary solvent interface. By steady state electrophoretic migration of charged colloids the electrophoretic force and the hydrodynamic resistance force are in equilibrium, described by: Those effects influence the electrofiltration of biopolymers, which could be also charged, not only by the hydrodynamic resistance force but also by the electric field force. Focusing on the cathode side reveals that the negatively charged particles are affected by the electric field force, which is opposite to the hydrodynamic resistance force. In this manner the formation of filter cake on this side is impeded or in ideal situation filter cake is not formed at all. In this case the electric field is referred as critical electric field "E". As a result of the equilibrium of those forces, liquids subjected to the influence of electric force become charged. In addition to the applied hydraulic pressure ∆pH the process is influenced also by the electro-osmotic pressure "P" | https://en.wikipedia.org/wiki?curid=23627434 |
Electrofiltration Modifying the Darcy’s basic equation, describing filter cake formation, with electro-kinetic effects by integration under assumption of using the constants of electro-osmotic pressure "P", the critical electric field "E" and the electric field "E" results: Previous scientific works conducted in the Dept. of Bioprocess Engineering, Institute of Engineering in Life Sciences, University of Karlsruhe demonstrated that electrofiltration is effective for the concentration of charged biopolymers. Very promising results concerning purification of the charged polysaccharide xanthan are already obtained. Figure 2 represents xanthan filter cake. | https://en.wikipedia.org/wiki?curid=23627434 |
Ehrlich's reagent or Ehrlich reagent is a reagent that contains "p"-dimethylaminobenzaldehyde (DMAB) and thus can act as an indicator to presumptively identify indoles and urobilinogen. Several Ehrlich tests use the reagent in a medical test; some are drug tests and others contribute to diagnosis of various diseases or adverse drug reactions. A very common Ehrlich test is a simple spot test to identify possible psychoactive compounds such as tryptamines (e.g. DMT) and ergoloids (e.g. LSD). The reagent will also give a positive result for opium, despite the opiates not containing the indole functional group, because of the presence of tryptophan in natural opium. It is named after Nobel Prize winner Paul Ehrlich who used it to distinguish typhoid from simple diarrhoea. The reagent is prepared by dissolving 0.5–2.0 g of "p"–dimethylaminobenzaldehyde (DMAB) in 50 mL of 95% ethanol and 50 mL of concentrated hydrochloric acid and is best used when fresh. Other alcohols, such as 1-propanol, can also be used as well. The Ehrlich reagent is similar to a number of other indole tests: The Ehrlich reagent works by binding to the C2 position of two indole moieties to form a resonance stabilised carbenium ion compound. | https://en.wikipedia.org/wiki?curid=23640235 |
Superior multimineral process The (also known as the McDowell–Wellman process or circular grate process) is an above ground shale oil extraction technology designed for production of shale oil, a type of synthetic crude oil. The process heats oil shale in a sealed horizontal segmented vessel (retort) causing its decomposition into shale oil, oil shale gas and spent residue. The particularities of this process is a recovery of saline minerals from the oil shale, and a doughnut-shape of the retort. The process is suitable for processing of mineral-rich oil shales, such as in the Piceance Basin. It has a relatively high reliability and high oil yield. The technology was developed by the American oil company Superior Oil. The multimineral process was developed by Superior Oil Company, now part of ExxonMobil, for processing of the Piceance Basin's oil shale. The technology tests were carried out in pilot plants in Cleveland, Ohio. In the 1970s, Superior Oil planned a commercial-size demonstration plant in the northern Piceance Basin area with a capacity of of shale oil per day; however, because of low crude oil price these plans were never implemented. The process was developed to combine the shale oil production with production of sodium bicarbonate, sodium carbonate, and aluminum from nahcolite and dawsonite, occurring in oil shales of the Piceance Basin. In this process, the nahcolite is recovered from the raw oil shale by crushing it to lumps smaller than | https://en.wikipedia.org/wiki?curid=23642093 |
Superior multimineral process As a result, most of the nahcolite in the oil shale becomes a fine powder what could screened out. Screened oil shale lumps are further crushed to particles smaller than . Oil shale particles are further processed in a horizontal segmented doughnut-shaped traveling-grate retort in the direct or indirect heating mode. The retort was originally designed by Davy McKee Corporation for iron ore pelletizing and it also known as the Dravo retort. In the direct retort, oil shale moves past ducts through which are provided hot inert gas for heating the raw oil shale, air for combustion of carbon residue (char or semi-coke) in the spent oil shale, and cold inert gas for cooling the spent oil shale. The oil pyrolysis takes place in the heating section. To minimize solubility of aluminium compounds in the oil shale, the heat control is a crucial factor. Necessary heat for pyrolysis is generated in the carbon recovery section by combustion of carbon residue (char or semi-coke) remained in the spent oil shale. While blowing inert gases through the spent oil shale, the spent oil shale is cooled and gases are heated to cause pyrolysis. The indirect mode is similar; the difference is that combustion of carbonaceous residue takes place in separate vessel. The last section is for discharging of oil shale ash. Aluminium oxide and sodium carbonate are recovered from calcined dawsonite and calcined nahcolite in the oil shale ash | https://en.wikipedia.org/wiki?curid=23642093 |
Superior multimineral process The traveling-grate retort allows close temperature control, and therefore better control of dawsonite's solubility during the burning stage. During retorting, there is no relative movement of oil shale, which avoids dust creation, and therefore increase the quality of generated products. The oil recovery yields greater than 98% Fischer Assay. The technology has also a relatively high reliability. The sealed system of this process has environmental advantage as it prevents gas and mist leakage. | https://en.wikipedia.org/wiki?curid=23642093 |
Dehalogenation is a chemical reaction that involves the cleavage of C-Halogen bond to form product. can be divided into two subclasses: reductive dehalogenation and hydro dehalogenation. Organic halides belong to a class of organic compounds that contain carbon-halogen bond. In 1832, scientist named Justus von Liebig synthesized the first organic halide (charcoal) via chlorination of ethanol. Since then, organohalides have gained a lot of attention. Organohalides are commonly used as pesticides, biodegradables, soil fumigants, refrigerants, chemical reagents – solvents, and polymers. It has been classified as pollutant despite of their wide use in various applications. Due to which, dehalogenation is a key reaction to convert toxic organohalides to less hazardous products. Among halogens, fluorine is the most electronegative atom and will have the highest tendency to make the strongest bond with carbon. The rate of dehalogenation depends on the bond strength between carbon and halogen atom. The bond dissociation energies of carbon-halogen bonds are described as: H3C-I (234 KJmol-1), H3C-Br (293 KJmol-1), H3C-Cl (351 KJmol-1), and H3C-F (452 KJmol-1). Thus, for the same structures the bond dissociation rate for dehalogenation will be: F« Cl Additionally, the rate of dehalogenation for alkyl halide also varies with steric environment and follows this trend: primary > secondary > tertiary halides. The rate of dehalogenation differs with the type of substrate, metal’s oxidation state, and reducing agents used during the reaction | https://en.wikipedia.org/wiki?curid=23642182 |
Dehalogenation Alkali and alkaline earth metals such as lithium, sodium, potassium, magnesium, and calcium have proven to be great dehalogenation catalysts. During dehalogenation reaction, the metals act as a reducing agent to break down carbon-halogen bonds. Halogen can then leave as a leaving group. The generic way to synthesize alkanes using alkali and alkaline-earth metal is shown in scheme 2: Yus and his co-workers synthesized various lithium naphthalenide compounds that acts as a catalyst for lithiation of different functionalized halogenated arenes. The Li-arene reacted with water or deuterium to produce the dehalogenated product. The major drawback of using lithium naphthalene catalysts is that it is hard to separate from the reaction mixture because naphthalene adsorbs on surface of arene substrates. In polymer chemistry, sodium metal has been used for dehalogenation process. Removal of halogen atom from arene-halides in the presence of Grignard agent and water for the formation of new compound is known as Grignard degradation. using Grignard reagents is a two steps hydrodehalogenation process. The reaction begins with the formation of alkyl/arene-magnesium-halogen compound, followed by addition of proton source to form dehalogenated product. Egorov and his co-workers have reported dehalogenation of benzyl halides using atomic magnesium in 3P state at 600°C. Toluene and bi-benzyls were produced as the product of the reaction | https://en.wikipedia.org/wiki?curid=23642182 |
Dehalogenation Morisson and his co-workers also reported dehalogenation of organic halides by flash vacuum pyrolysis using magnesium. Many groups have reported dehalogenation processes using different forms of homogeneous and heterogeneous transition metal complexes such as 0M, metal-ligand complexes, metal salts, and metal supported on different supports. Vanadium compounds in its low oxidation state tends to perform dehalogenation reaction via one electron reduction. The efficiency of the one-electron transfer system depends on the redox potential of both the vanadium complexes and the radicophiles. Lithium chromium(I) dihydride has also been used as a versatile reducing agent to dehalogenate various alkyl or aryl halides as shown in scheme 3: Other than these metals, iron is the most studied metal for the dehalogenation reaction. Cahiez and his co-workers reported reduction of bromo-alkenes using manganese(II) halide in presence of Fe(acac)3. Inspired by this work, Mohammed and coworkers also performed hydrobromination of 1,1,-dibromo-1-alkenes in presence of Grignard agents and transition metals such as Fe and Cobalt. Macromolecules such as Hematin, cobalamin, vitamin B12, and coenzyme F430 are also used for dichlorination of polychlorinated ethylenes and benzenes. Charles and his co-workers reported that Vitamin B12 and coenzyme F430 were capable of sequentially dechlorinating tetrachloroethylene to ethylene, while hematin was demonstrated to dechlorinate tetrachloroethylene to vinyl chloride | https://en.wikipedia.org/wiki?curid=23642182 |
Dehalogenation Javier and his-coworkers reported the synthesis of Iron (II) fluoride complexes. The complexes were then used as precursor and precatalysts for hydrodefluorination of fluorocarbons. They reported the first synthesis of a three-coordinate iron-fluoride complex. Jayant and his coworkers developed two phase systems for dehalogenation of trichloroethylenes. The kinetic model provides reaction process to take place in one phase while mass transfer between two phases. There have been several reports on dehalogenation process performed using various other metals such as cobalt, nickel, palladium, silicon, and germanium. | https://en.wikipedia.org/wiki?curid=23642182 |
Nitrobenzaldehyde may refer to any of the three isomeric chemical compounds : | https://en.wikipedia.org/wiki?curid=23648676 |
Fucosylation is the process of adding fucose sugar units to a molecule. It is a type of glycosylation. It is important clinically, and high levels of fucusylation have been reported in cancer. It is performed by fucosyltransferase enzymes. has been observed in vertebrates, invertebrates, plants, bacteria, and fungi. It is known to facilitate various functions including cellular adhesion and immune regulation. inhibition applications are being explored for a range of clinical application including some associated with sickle cell disease, rheumatoid arthritis, tumor inhibition, and chemotherapy improvements. | https://en.wikipedia.org/wiki?curid=23648859 |
Cell casting is a method used for creating poly(methyl methacrylate) (PMMA) sheets. Liquid monomer is poured between two flat sheets of toughened glass sealed with a rubber gasket and heated for polymerization. Because the glass sheets may contain surface scratches or sag during the process, this traditional method has some disadvantages: among other problems, the PMMA sheets may contain variations in thickness and surface defects. It has since been replaced by the more modern method for making PMMA, extrusion, which gives uniform quality. "Cell Casting - A process in which a casting liquid is poured between two plates, usually glass, that have a gasket between them to form a cell to contain the casting liquid; then the resin solidifies, usually through polymerization or crosslinking." - A. Brent Strong | https://en.wikipedia.org/wiki?curid=23649157 |
Cast iron pipe is pipe made predominantly from gray cast iron It was historically used as a pressure pipe for transmission of water, gas and sewage, and as a water drainage pipe during the 17th, 18th, 19th and 20th centuries. was frequently used uncoated, although later coatings and linings reduced corrosion and improved hydraulics. In cast iron pipe, the graphite forms flakes during the casting process, when examined under a microscope. was superseded by ductile iron pipe, which is a direct development, with most existing manufacturing plants transitioning to the new material during the 1970s and 1980s. Ductile iron pipe is different than cast iron, because the introduction of magnesium during the casting process causes the graphite to form spheres (graphite nodules) rather than flakes. While this allows the material to remain castable, the end product is much tougher than cast iron, and allows elastic behavior at lower stress levels. Little cast iron pipe is currently manufactured, since ductile iron pipe is widely accepted as a superior product. Many public utilities, municipalities, and private industries still have functional cast iron pipe in service to this day. The oldest cast iron water pipes date from the 17th century and were installed to distribute water throughout the gardens of the Chateau de Versailles. These amount to some 35 km of pipe, typically 1 m lengths with flanged joints. The extreme age of these pipes make them of considerable historical value | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe Despite extensive refurbishment in 2008 by Saint-Gobain PAM, 80% remain original. Cast iron proved to be a beneficial material for the manufacture of water pipes and was used as a replacement for the original elm pipelines utilized earlier. These water pipelines were composed of individually cast pipe sections, often termed sticks, jointed together by a variety of joint mechanisms. Flanged joints consisted of flat machined surfaces that were tightly bolted together with a gasket between them to prevent leakage. This type of pipe joint is still in use today, typically for above-ground pipelines in water treatment and manufacturing plants. In a bell and spigot joint one end of the pipe stick is flared, termed the bell or socket, to enable the opposite end of the next stick, the spigot end, to be inserted to create a joint. The gaps in these joints were stuffed with oakum or yarn to retain molten-lead, which solidified into a waterproof joint. This was a labor-intensive operation, and the quality of the seal was dependent on the skill of the laborer. Mechanical joints were made by bolting a movable follower ring on the spigot close to the corresponding bell, which compressed a gasket in between. Many water pipes today use mechanical joints, since they are easily made and do not require special skills to install | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe This type of joint also allows some deflection to occur without sacrificing joint integrity, so that minor alignment adjustments can be made during installation, and the joints retain their integrity when subjected to limited subsidence. Typical joint deflections at mechanical joints today range anywhere from 3 to 5 degrees. Ball-and-socket joints introduced more 'rounded' sockets, allowing a relatively large amount of deflection at each joint. This type of joint, still in use today, was considered a special-purpose joint, and has been used primarily in both submerged and mountainous terrain. This type of joint can typically allow around 15 degrees of deflection at each joint, making 'snaking' of the pipe possible. The advantage of this joint type was that it was quicker than bell and spigot joints, and did not require special skills or tools to install. Push-on joints, developed in the mid 1950s, allowed a quicker and relatively non-skilled method of jointing pipe. This joint consisted of a bell with a recessed groove which held a rubberized gasket. A lubricated beveled spigot section can be pushed into this joint with care, as not to roll the rubberized gasket, and once installed became watertight. This type of jointing system is popular today with ductile iron and Polyvinyl chloride (PVC) pipes. The first cast iron pipe was produced in horizontal moulds, the core of the mould would be supported on small iron rods which would become part of the pipe | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe Horizontal casting resulted in an uneven distribution of metal around the pipe circumference. Typically slag would collect at the crown of the pipe creating a much weaker section. In 1845, the first pipe was cast vertically in a pit and by the end of the century, all pipe was manufactured by this method. Using this method the slag would all collect at the top of the casting and could be removed by simply cutting off the end of the pipe. Pipes cast using this method often suffered from off centre bores caused by the core of the mould being placed off centre, resulting in one side of the pipe being thicker than the other. Subsequent to its invention by Dimitri Sensaud deLavaud, a French-Brazilian, in 1918, much cast iron pipe manufacturing shifted to the dramatically different technique of centrifugal casting. Modern ductile iron pipe production continues to use this general method of casting. Historically, two different types of molds have been used in centrifugal casting of cast iron pipe: metal molds and sand molds. With metal molds, molten iron was introduced into the mold to uniformly distribute metal over the interior of the mold surface by the centrifugal force generated. The outside mold was typically protected from damage by a controlled water bath or water spray system. When the pipe was cool enough to be handled and hold its shape, the mold was stopped and the pipe removed | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe Pipe formed in metal molds were typically annealed after casting to eliminate any stresses in the pipe, and were then cleaned, inspected, tested, gauged (for dimensions), coated internally and/or externally, and stored for use. Standards for cast-iron pipe centrifugally cast in metal molds for water were established and published by the American Water Works Association. When casted with sand molds, two types of manufacturing processes were used. In the first method, a metal pattern was typically positioned in a metal flask and molding sand was rammed into the annular space between the flask and pattern. The pattern was then removed for casting of the pipe using molten grey iron. The second method did not entail a metal pattern, but entailed the forming of the mold centrifugally by lining the heated flask with a measured amount of thermosetting resin and sand. Either way, the casting machine was stopped after the pipe had solidified and the flask was removed. formed using this procedure was typically oven-cooled under controlled time and temperature conditions. As with metal molds, pipe was typically annealed to eliminate any stresses in the pipe, and were then cleaned, inspected, tested, gauged (for dimensions), coated internally and/or externally, and stored for use. Standards for cast-iron pipe centrifugally cast in sand molds for water were established and published by the American Water Works Association. Corrosion of cast-iron-pipe can occur on both the internal and external surfaces | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe In electro-chemical corrosion, internal anodes develop where bare iron is exposed to aggressive waters, promoting iron to move into solution. The iron combines with various components in the water, forming a tubercle on the pipe interior. This process of tuberculation can eventually cause significant restrictions in cross-sectional area within the pipe. Since the tubercles are irregularly shaped, buildup of bacterial growths on the surface are likely. As more iron moves into solution, the result is a loss of pipe structure over time potentially affecting pipe integrity. In storm and sanitary sewer systems, the creation of acidic gases (such as hydrogen sulfide) by microbial action can further corrode internal pipe walls but is most pronounced on the inside ‘ceiling’ of the pipe. Starting in 1922, internal cement linings were introduced to act as a barrier to minimize internal corrosion. In 1929, the American Standard Association (ASA) Sectional Committee issued a tentative standard for cement-mortar linings, which was published in 1932. In 1939, American Standard A21.4 was published, which defined a Type I cement coating on the inside of waterline pipe to be used. When the standard was updated in 1953, the Type I cement was replaced with Type II, since it was believed that Type II was a more closely controlled product. The standard was further revised in 1964, which included the use of either Type I or Type II cement, and making two different mortar thicknesses available | https://en.wikipedia.org/wiki?curid=23649298 |
Cast iron pipe The first standardization of cast iron water pipes in Britain occurred in 1917 with the publishing of BS 78. This standard specified a dimensionless nominal size, which approximately corresponded with the internal diameter in inches of the pipe, and four pressure classes, Class A, Class B, Class C and Class D, each with a specified wall thickness and outer diameter. It is noted that the outer diameter is identical between classes with the exception of sizes 12 to 27, where Classes A and B share one diameter and Classes C and D have another, larger diameter. BS 78 was finally superseded when the U.K. harmonised with incompatible European standards, however, the specified outer dimensions continue to remain in effect (albeit in metric form) as the standard pipe outer diameter for ductile iron pipe in Australia and New Zealand through the descendant specification, AS/NZS 2280. | https://en.wikipedia.org/wiki?curid=23649298 |
Topological insulator A topological insulator is a material that behaves as an insulator in its interior but whose surface contains conducting states, meaning that electrons can only move along the surface of the material. Topological insulators have non-trivial symmetry-protected topological order; however, having a conducting surface is not unique to topological insulators, since ordinary band insulators can also support conductive surface states. What is special about topological insulators is that their surface states are symmetry-protected Dirac fermions. by particle number conservation and time-reversal symmetry. In two-dimensional (2D) systems, this ordering is analogous to a conventional electron gas subject to a strong external magnetic field causing electronic excitation gap in the sample bulk and metallic conduction at the boundaries or surfaces. The distinction between 2D and 3D topological insulators is characterized by the Z-2 topological invariant, which defines the ground state. In 2D, there is a single Z-2 invariant distinguishing the insulator from the quantum spin-Hall phase whiles in 3D, there are four Z-2 invariant that differentiate the insulator from “weak” and “strong” topological insulators. In the bulk of a non-interacting topological insulator, the electronic band structure resembles an ordinary band insulator, with the Fermi level falling between the conduction and valence bands | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator On the surface of a topological insulator there are special states that fall within the bulk energy gap and allow surface metallic conduction. Carriers in these surface states have their spin locked at a right-angle to their momentum (spin-momentum locking). At a given energy the only other available electronic states have different spin, so the "U"-turn scattering is strongly suppressed and conduction on the surface is highly metallic. Non-interacting topological insulators are characterized by an index (known as formula_1 topological invariants) similar to the genus in topology. As long as time-reversal symmetry is preserved (i.e., there is no magnetism), the formula_1 index cannot change by small perturbations and the conducting states at the surface are symmetry-protected. On the other hand, in the presence of magnetic impurities, the surface states will generically become insulating. Nevertheless, if certain crystalline symmetries like inversion are present, the formula_1 index is still well defined. These materials are known as magnetic topological insulators and their insulating surfaces exhibit a half-quantized surface anomalous Hall conductivity. Photonic topological insulators are the classical-wave electromagnetic counterparts of (electronic) topological insulators, that provide unidirectional propagation of electromagnetic waves | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator Time-reversal symmetry-protected two-dimensional edge states were predicted in 1987 by Oleg Pankratov to occur in quantum wells (very thin layers) of mercury telluride sandwiched between cadmium telluride, and were observed in 2007. It was discovered that electrons that are confined to two dimensions and subject to strong magnetic field show a different topological ordering, which underlies the quantum Hall effect. The effect of this topological ordering results in the emergence of particles with fractional charges and non-dissipation transport. The distinguishing features of topological materials stems in the fact that they are insulating (have energy gaps) in the bulk but have a "protected" metallic properties (gapless) at the edge or surface state. These "protected" gapless states are governed by the time-reversal symmetry and the band structure of the material. In 2007, it was predicted that similar topological insulators might be found in binary compounds involving bismuth, and in particular "strong topological insulators" exist that cannot be reduced to multiple copies of the quantum spin Hall state. Topological insulators were first realized in 2D in system containing HgTe quantum wells sandwiched between cadmium telluride in 2007. The first 3D topological insulator to be realized experimentally was Bi Sb . Bismuth in its pure state, is a semimetal with a small electronic band gap | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator Using angle- resolved photoemission spectroscopy, and other measurements, it was observed that BiSb alloy exhibits an odd surface state (SS) crossing between any pair of Kramers points and the bulk features massive Dirac fermions. Additionally, bulk BiSb has been predicted to have 3D Dirac particles. This prediction is of particular interest due to the observation of charge quantum Hall fractionalization in 2D graphene and pure bismuth. Shortly thereafter symmetry-protected surface states were also observed in pure antimony, bismuth selenide, bismuth telluride and antimony telluride using angle-resolved photoemission spectroscopy (ARPES). and bismuth selenide. Many semiconductors within the large family of Heusler materials are now believed to exhibit topological surface states. In some of these materials, the Fermi level actually falls in either the conduction or valence bands due to naturally-occurring defects, and must be pushed into the bulk gap by doping or gating. The surface states of a 3D topological insulator is a new type of two-dimensional electron gas (2DEG) where the electron's spin is locked to its linear momentum.<ref name="doi10.1038/nature08234"></ref> Fully bulk-insulating or intrinsic 3D topological insulator states exist in Bi-based materials as demonstrated in surface transport measurements | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator In a new Bi based chalcogenide (BiSbTeS) with slightly Sn - doping, exhibits an intrinsic semiconductor behavior with Fermi energy and Dirac point lie in the bulk gap and the surface states were probed by the charge transport experiments. In was proposed in 2008 and 2009 that topological insulators are best understood not as surface conductors per se, but as bulk 3D magnetoelectrics with a quantized magnetoelectric effect. This can be revealed by placing topological insulators in magnetic field. The effect can be described in language similar to that of the hypothetical axion particle of particle physics. The effect was reported by researchers at Johns Hopkins University and Rutgers University using THz spectroscopy who showed that the Faraday rotation was quantized by the fine structure constant. In 2012, topological Kondo insulators were identified in samarium hexaboride, which is a bulk insulator at low temperatures. In 2014, it was shown that magnetic components, like the ones in spin-torque computer memory, can be manipulated by topological insulators. The effect is related to metal–insulator transitions (Bose–Hubbard model). Spin-momentum locking in the topological insulator allows symmetry-protected surface states to host Majorana particles if superconductivity is induced on the surface of 3D topological insulators via proximity effects. (Note that Majorana zero-mode can also appear without topological insulators | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator ) The non-trivialness of topological insulators is encoded in the existence of a gas of helical Dirac fermions. Dirac particles which behave like massless relativistic fermions have been observed in 3D topological insulators. Note that the gapless surface states of topological insulators differ from those in the quantum Hall effect: the gapless surface states of topological insulators are symmetry-protected (i.e., not topological), while the gapless surface states in quantum Hall effect are topological (i.e., robust against any local perturbations that can break all the symmetries). The formula_1 topological invariants cannot be measured using traditional transport methods, such as spin Hall conductance, and the transport is not quantized by the formula_1 invariants. An experimental method to measure formula_1 topological invariants was demonstrated which provide a measure of the formula_1 topological order. (Note that the term formula_1 topological order has also been used to describe the topological order with emergent formula_1 gauge theory discovered in 1991.) More generally (in what is known as the "ten-fold way") for each spatial dimensionality, each of the ten Altland—Zirnbauer symmetry classes of random Hamiltonians labelled by the type of discrete symmetry (time-reversal symmetry, particle-hole symmetry, and chiral symmetry) has a corresponding group of topological invariants (either formula_10, formula_1 or trivial) as described by the periodic table of topological invariants | https://en.wikipedia.org/wiki?curid=23649871 |
Topological insulator The most promising applications of topological insulators are spintronic devices and dissipationless transistors for quantum computers based on the quantum Hall effect and quantum anomalous Hall effect. In addition, topological insulator materials have also found practical applications in advanced magnetoelectronic and optoelectronic devices. Topological insulators can be grown using different methods such as metal-organic chemical vapor deposition (MOCVD), solvothermal synthesis, sonochemical technique and molecular beam epitaxy (MBE). MBE has so far been the most common experimental technique used in the growth of topological insulators. The growth of thin film topological insulators is governed by weak Van der Waals interactions. The weak interaction allows to exfoliate the thin film from bulk crystal with a clean and perfect surface. The Van der Waals interactions in epitaxy also known as Van der Waals epitaxy (VDWE), is a phenomenon governed by weak Van der Waal’s interactions between layered materials of different or same elements in which the materials are stacked on top of each other. This approach allows the growth of layered topological insulators on other substrates for heterostructure and integrated circuits. Molecular Beam Epitaxial (MBE) growth of topological insulators MBE is an epitaxy method for the growth of a crystalline material on a crystalline substrate to form an ordered layer | https://en.wikipedia.org/wiki?curid=23649871 |
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