query: what is the first step in the nitrogen cycle when gaseous nitrogen is converted into ammonia

pos: Nitrogen cycle into a usable form to be taken up by plants. Between 5x10 and 10x10 g per year are fixed by lightning strikes, but most fixation is done by free-living or symbiotic bacteria known as diazotrophs. These bacteria have the nitrogenase enzyme that combines gaseous nitrogen is the with hydrogen to produce ammonia, which is converted by the bacteria into other organic compounds. Most biological nitrogen fixation occurs by the activity of Mo-nitrogenase, found in a wide variety of bacteria and some Archaea. Mo-nitrogenase is a complex two-component enzyme that has multiple metal-containing prosthetic groups. An example of free-living bacteria is

pos: Nitrogen fixation Nitrogen fixation Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH) or related nitrogenous compounds. Atmospheric nitrogen, which is molecular dinitrogen (N), is relatively nonreactive and is metabolically useless to all but a few microorganisms. The fixation process converts N into ammonia, which is metabolized by most organisms. Nitrogen fixation is essential to life because fixed inorganic nitrogen compounds are required for the biosynthesis of all nitrogen-containing compounds. Therefore, as part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer. It is also, indirectly, relevant to the

pos: Nitrogen the industrial synthesis of ammonia and nitric acid became common. Nitrogen compounds constantly interchange between the atmosphere and living organisms. Nitrogen must first be processed, or "fixed", into a plant-usable form, usually ammonia. Some nitrogen fixation is done by lightning strikes producing the nitrogen oxides, but most is done by diazotrophic bacteria through enzymes known as nitrogenases (although today industrial nitrogen fixation to ammonia is also significant). When the ammonia is taken up by plants, it is used to synthesise proteins. These plants are then digested by animals who use the nitrogen compounds to synthesise their own proteins and excrete

pos: Root hair curling Root hair curling Root hair curling is the process by which the root hairs of legume plants curl around bacteria to allow an infection into the cortical cells of the roots to form a nitrogen fixing nodule. Legume plants, just like all plants, need nitrogen in order to grow. Legumes include plants such as alfalfa, beans, peanuts, and lentils. Nitrogen is available in excess in the air, but it that form is not actually usable by plants. The gaseous form (N) must be reduced to ammonia (NH) in a process known as nitrogen fixation. This nitrogen fixation can occur in

pos: Rhizobacteria due to the high energy required to break the triple bonds between the two atoms. Rhizobacteria, through nitrogen fixation, are able to convert gaseous nitrogen (N) to ammonia (NH) making it an available nutrient to the host plant which can support and enhance plant growth. The host plant provides the bacteria with amino acids so they do not need to assimilate ammonia. The amino acids are then shuttled back to the plant with newly fixed nitrogen. Nitrogenase is an enzyme involved in nitrogen fixation and requires anaerobic conditions. Membranes within root nodules are able to provide these conditions. The rhizobacteria

pos: Tris(trimethylsilyl)amine °C) among other oligomers which gives upon heating over 250 °C high molecular weight, little defined polydichlorophosphazenes. Nitrogen trifluoride NF (which is used, inter alia, for the plasma etching of silicon wafers) is obtainable from tris(trimethylsilyl)amine and fluorine at –40 °C in acetonitrile, suppressing the formation of nitrogen and tetrafluorohydrazine, which are produced as undesirable by-products during the standard synthesis of nitrogen trifluoride from ammonia or ammonium fluoride. The technical nitrogen fixation was made possible by the Haber-Bosch process, in which nitrogen is converted into ammonia by reductive protonation in the presence of iron catalysts under high pressures (> 150

pos: Nitrogen cycle be utilized by phytoplankton as N so it must undergo nitrogen fixation which is performed predominately by cyanobacteria. Without supplies of fixed nitrogen entering the marine cycle, the fixed nitrogen would be used up in about 2000 years. Phytoplankton need nitrogen in biologically available forms for the initial synthesis of organic matter. Ammonia and urea are released into the water by excretion from plankton. Nitrogen sources are removed from the euphotic zone by the downward movement of the organic matter. This can occur from sinking of phytoplankton, vertical mixing, or sinking of waste of vertical migrators. The sinking results in

pos: Cyanobacteria of specialized cells called heterocysts. Heterocysts may also form under the appropriate environmental conditions (anoxic) when fixed nitrogen is scarce. Heterocyst-forming species are specialized for nitrogen fixation and are able to fix nitrogen gas into ammonia (), nitrites () or nitrates (), which can be absorbed by plants and converted to protein and nucleic acids (atmospheric nitrogen is not bioavailable to plants, except for those having endosymbiotic nitrogen-fixing bacteria, especially the Fabaceae family, among others). Free-living cyanobacteria are present in the water of rice paddies, and cyanobacteria can be found growing as epiphytes on the surfaces of the green alga,

pos: Nitrogen fixation protons and a strong reducing agent rather than with H itself. In 2011, yet another molybdenum-based system was discovered, but with a diphosphorus pincer ligand. Photolytic nitrogen splitting is also considered. Nitrogen fixation at a p-block element was published in 2018 whereby one molecule of dinitrogen is bound by two transient Lewis-base-stabilized borylene species. The resulting dianion was subsequently oxidized to a neutral compound, and reduced using water. Nitrogen fixation Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia (NH) or related nitrogenous compounds. Atmospheric nitrogen, which is molecular dinitrogen (N), is relatively

pos: Fertilizer This process was used to fix atmospheric nitrogen (N) into nitric acid (HNO), one of several chemical processes generally referred to as nitrogen fixation. The resultant nitric acid was then used as a source of nitrate (NO). A factory based on the process was built in Rjukan and Notodden in Norway, combined with the building of large hydroelectric power facilities. The 1910s and 1920s witness the rise of the Haber process and the Ostwald process. The Haber process produces ammonia (NH) from methane (CH) gas and molecular nitrogen (N). The ammonia from the Haber process is then converted into nitric

pos: Vanadium nitrogenase Vanadium nitrogenase Vanadium nitrogenase is a key enzyme for nitrogen fixation found in nitrogen-fixing bacteria, and is used as an alternative to molybdenum nitrogenase when molybdenum is unavailable. Vanadium nitrogenases are an important biological use of vanadium, which is uncommonly used by life. An important component of the nitrogen cycle, vanadium nitrogenase converts nitrogen gas to ammonia, thereby making otherwise inaccessible nitrogen available to plants. Unlike molybdenum nitrogenase, vanadium nitrogenase can also reduce carbon monoxide to ethylene, ethane and propane but both enzymes can reduce protons to hydrogen gas and acetylene to ethylene. Vanadium nitrogenases are found in members of

pos: Nitrogenase Nitrogenase Nitrogenases are enzymes () that are produced by certain bacteria, such as cyanobacteria (blue-green algae). These enzymes are responsible for the reduction of nitrogen (N) to ammonia (NH). Nitrogenases are the only family of enzymes known to catalyze this reaction, which is a key step in the process of nitrogen fixation. Nitrogen fixation is required for all forms of life, with nitrogen being essential for the biosynthesis of molecules (nucleotides, amino acids) that create plants, animals and other organisms. The equilibrium formation of ammonia from molecular hydrogen and nitrogen has an overall negative enthalpy of reaction (formula_1), the activation

pos: Nitrogen fixation the N molecule. Lightning produces enough energy and heat to break this bond allowing the nitrogen atoms to react with oxygen forming NOx. This itself cannot be used by plants, but as this molecule cools down it reacts with more oxygen to form NO. This molecule in turn reacts with water to produce HNO (nitric acid) which is usable by plants. Biological nitrogen fixation was discovered by the German agronomist Hermann Hellriegel and Dutch microbiologist Martinus Beijerinck. Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called a nitrogenase. The overall reaction for BNF

pos: Soil matter overall, would release of nitrogen as ammonium per acre. In nitrogen fixation, rhizobium bacteria convert N to ammonia (NH). Rhizobia share a symbiotic relationship with host plants, since rhizobia supply the host with nitrogen and the host provides rhizobia with nutrients and a safe environment. It is estimated that such symbiotic bacteria in the root nodules of legumes add 45 to 250 pounds of nitrogen per acre per year, which may be sufficient for the crop. Other, free-living nitrogen-fixing bacteria and blue-green algae live independently in the soil and release nitrate when their dead bodies are converted by way

pos: Ammonia although oxidation of liquid ammonia is usually slow, there is still a risk of explosion, particularly if transition metal ions are present as possible catalysts. Ammonia is both a metabolic waste and a metabolic input throughout the biosphere. It is an important source of nitrogen for living systems. Although atmospheric nitrogen abounds (more than 75%), few living creatures are capable of using this atmospheric nitrogen in its diatomic form, N gas. Therefore, nitrogen fixation is required for the synthesis of amino acids, which are the building blocks of protein. Some plants rely on ammonia and other nitrogenous wastes incorporated into

pos: Nutrient cycling in the Columbia River Basin activity has contributed over 50 percent of the available global reactive nitrogen. The Haber-Bosch process is an artificial means of nitrogen fixation, producing over 450 million tons of ammonia per year. Much of this yield is used for agricultural purposes through fertilizers. Agricultural sources of nitrogen reach rivers primarily through the erosion of soil sediments, but also through airborne dust and gaseous transport of volatilized NH from livestock manure and fertilizers. At the beginning of the twentieth century, agriculture began to exceed mining and became the Columbia River Basin's primary economic industry. The Columbia River has been subject to cultural

neg: Hydrazine ethane. These structural properties resemble those of gaseous hydrogen peroxide, which adopts a "skewed" anticlinal conformation, and also experiences a strong rotational barrier. Diverse routes have been developed. The key step is the creation of the nitrogen–nitrogen single bond. The many routes can be divided into those that use chlorine oxidants (and generate salt) and those that do not. Hydrazine can be synthesized from ammonia and hydrogen peroxide in the Peroxide process (sometimes called Pechiney-Ugine-Kuhlmann process, the Atofina–PCUK cycle, or ketazine process). The net reaction follows: In this route, the ketone and ammonia first condense to give the imine, which

neg: Ammonia production (liquefied petroleum gases such as propane and butane) or petroleum naphtha into gaseous hydrogen. The method for producing hydrogen from hydrocarbons is known as steam reforming. The hydrogen is then combined with nitrogen to produce ammonia via the Haber-Bosch process. Starting with a natural gas feedstock, the processes used in producing the hydrogen are: To produce the desired end-product ammonia, the hydrogen is then catalytically reacted with nitrogen (derived from process air) to form anhydrous liquid ammonia. This step is known as the ammonia synthesis loop (also referred to as the Haber-Bosch process): Due to the nature of the (typically

neg: Aquarium as "Nitrospira", it has recently been found that "Nitrobacter" are not present in detectable levels in established aquaria, while "Nitrospira" are plentiful.) However, commercial products sold as kits to "jump start" the nitrogen cycle often still contain "Nitrobacter". In addition to bacteria, aquatic plants also eliminate nitrogen waste by metabolizing ammonia and nitrate. When plants metabolize nitrogen compounds, they remove nitrogen from the water by using it to build biomass that decays more slowly than ammonia-driven plankton already dissolved in the water. What hobbyists call the nitrogen cycle is only a portion of the complete cycle: nitrogen must be added

neg: Nitrification step of the cycle is of particular interest in the ocean because it creates nitrate, the primary form of nitrogen responsible for "new" production. Furthermore, as the ocean becomes enriched in anthropogenic CO, the resulting decrease in pH could lead to decreasing rates of nitrification. Nitrification could potentially become a "bottleneck" in the nitrogen cycle. Nitrification, as stated above, is formally a two-step process; in the first step ammonia is oxidized to nitrite, and in the second step nitrite is oxidized to nitrate. Different microbes are responsible for each step in the marine environment. Several groups of ammonia-oxidizing bacteria (AOB)

neg: Nitrogen act as reducing agents themselves. They are an intermediate step in the oxidation of ammonia to nitrite, which occurs in the nitrogen cycle. Hyponitrite can act as a bridging or chelating bidentate ligand. Nitrous acid (HNO) is not known as a pure compound, but is a common component in gaseous equilibria and is an important aqueous reagent: its aqueous solutions may be made from acidifying cool aqueous nitrite (, bent) solutions, although already at room temperature disproportionation to nitrate and nitric oxide is significant. It is a weak acid with p"K" 3.35 at 18 °C. They may be titrimetrically analysed

neg: Ornithine Ornithine Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. -Ornithine is one of the products of the action of the enzyme arginase on -arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen. Ornithine is recycled and, in a manner, is a catalyst. First, ammonia is converted into carbamoyl phosphate (). Ornithine is converted into a urea derivative at the δ (terminal) nitrogen by carbamoyl phosphate synthetase. Another

neg: Nitrification the oxygen atoms), and is catalyzed step-wise by a series of enzymes. OR In Nitrosomonas europaea, the first step of oxidation (ammonia to hydroxylamine) is carried out by the enzyme ammonia monooxygenase (AMO). The second step (hydroxylamine to nitrite) is carried out step-wise by two different enzymes. Hydroxylamine oxidoreductase (HAO), converts hydroxylamine to nitric oxide. Another as-of-yet unknown enzyme that converts nitric oxide to nitrite. The third step (nitrite to nitrate) is completed in a different organism. In the marine environment, nitrogen is often the limiting nutrient, so the nitrogen cycle in the ocean is of particular interest. The nitrification

neg: Ammoniacal nitrogen water. Ammonia is toxic to fish and humans. The toxicity is decreased with lower alkalinity and increases with higher alkalinity as ammonium is converted to ammonia. There are 3 main forms of nitrogen: Molecular nitrogen is the gas form of nitrogen in the atmosphere. The chemical structure for nitrogen gas is N. The mineral forms of nitrogen are: Ammoniums ions are nitrified and are converted by microorganisms into nitrate. Fish and humans are more tolerant of nitrate nitrogen than they are of ammonium nitrogen. In well aerated water, most of the mineral nitrogen is in the form of nitrate. See

neg: Selective catalytic reduction Selective catalytic reduction Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen () , and water (). A gaseous reductant, typically anhydrous ammonia, aqueous ammonia or urea, is added to a stream of flue or exhaust gas and is adsorbed onto a catalyst. Carbon dioxide, is a reaction product when urea is used as the reductant. Selective catalytic reduction of using ammonia as the reducing agent was patented in the United States by the Engelhard Corporation in 1957. Development of SCR technology continued in Japan

neg: Microbiology of oxygen minimum zones play its part. Under these anoxic conditions, nitrate is reduced to gaseous nitrogen or nitrite and ammonia in a process called dissimilatory nitrate reduction by the protein nitrate reductase. The ammonia and nitrite produced are further reduced by anaerobic ammonia-oxidizing bacteria (anammox) using an enzyme called hydrazine oxidoreductase. Genomic studies conducted in these ecosystems reveal a growing abundance of the genes encoding for the proteins responsible for the dissimilatory nitrate reduction and anammox at the core of these OMZs. Such studies also provide information to map out the nitrogen cycle in the water column and provide with missing links and

neg: Nitrogen cycle respiration and consequently produce nitrogen gas, which is inert and unavailable to plants. Dissimilatory nitrate reduction to ammonium (DNRA), or nitrate/nitrite ammonification, is an anaerobic respiration process. Microbes which undertake DNRA oxidise organic matter and use nitrate as an electron acceptor, reducing it to nitrite, then ammonium (NO→NO→NH). Both denitrifying and nitrate ammonification bacteria will be competing for nitrate in the environment, although DNRA acts to conserve bioavailable nitrogen as soluble ammonium rather than producing dinitrogen gas. In this biological process, nitrite and ammonia are converted directly into molecular nitrogen (N) gas. This process makes up a major proportion of

neg: Urea cycle aquatic organisms, or ammonotelic organisms, excrete ammonia without converting it. Ammonia is toxic, but upon excretion from aquatic species, it is diluted by the water outside the organism. Organisms that cannot easily and safely remove nitrogen as ammonia convert it to a less toxic substance such as urea or uric acid. The urea cycle mainly occurs in the liver. The urea produced by the liver is then released into the bloodstream where it travels to the kidneys and is ultimately excreted in urine. In species including birds and most insects, the ammonia is converted into uric acid or its urate

neg: Nitrification although the modes of action distinguishing them are unclear. Nitrification Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil. Nitrification is an aerobic process performed by small groups of autotrophic bacteria and archaea. This process was discovered by the Russian microbiologist Sergei Winogradsky. The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). AOB

neg: Liquid nitrogen wash Liquid nitrogen wash The Liquid Nitrogen Wash is mainly used for the production of ammonia synthesis gas within fertilizer production plants. It is usually the last purification step in the ammonia production process sequence upstream of the actual ammonia production. The purpose of the final purification step upstream of the actual ammonia production is to remove all components that are poisonous for the sensitive ammonia synthesis catalyst. This can be done with the following concepts: The Liquid Nitrogen Wash has two principle functions: The carbon monoxide must be removed completely from the synthesis gas (i.e. syngas) since it is poisonous

neg: Nitrification Nitrification Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil. Nitrification is an aerobic process performed by small groups of autotrophic bacteria and archaea. This process was discovered by the Russian microbiologist Sergei Winogradsky. The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). AOB can be found among the β-proteobacteria and gammaproteobacteria. Currently,

neg: Aquarium invertebrates, fungi, and some bacteria excrete nitrogen waste in the form of ammonia (which converts to ammonium, in water) and must then either pass through the nitrogen cycle or be removed by passing through zeolite. Ammonia is also produced through the decomposition of plant and animal matter, including fecal matter and other detritus. Nitrogen waste products become toxic to fish and other aquarium inhabitants at high concentrations. In the wild, the vast amount of water surrounding the fish dilutes ammonia and other waste materials. When fish are put into an aquarium, waste can quickly reach toxic concentrations in the enclosed

neg: Argininosuccinate synthase the liver from processing excess nitrogen into urea. As a result, nitrogen (in the form of ammonia) and other byproducts of the urea cycle (such as citrulline) build up in the bloodstream. Ammonia is toxic, particularly to the nervous system. An accumulation of ammonia during the first few days of life leads to poor feeding, vomiting, seizures, and the other signs and symptoms of type I citrullinemia. Treatment for this defect includes a low-protein diet and dietary supplementation with arginine and phenylacetate. Arginine allows the urea cycle to complete itself, creating the substrates needed to originally fix ammonia. This will

neg: BMA process approximately 1400 °C. The reaction mixture contains around 23 Vol.-% HCN and 72 Vol.-% H as well as minor quantities of ammonia, nitrogen, and unreacted methane. The gaseous mixture is introduced in a scrubber and treated with an ammonia solution (producing ammonium cyanide) allowing the other gaseous components: H, CH, and N to pass through. In a second step the HCN is released by acidification of the solution, followed by a final distillation of the hydrogen cyanide. Because of the highly endothermic reaction, the BMA process is of lower importance for the production of HCN compared to the Andrussow process.

neg: Nitrogen cycle Nitrogen cycle The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmosphere nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because

neg: Sable Chemicals is 240 000 tonnes per annum of AN . An air separation process is used to separate nitrogen from air for downstream use in the ammonia making process. By-products in the form of gaseous and liquid oxygen as well as small quantities of liquid nitrogen are formed. Five basic unit operations make up the air separation process: air compression, air purification, heat exchange, liquefaction and distillation. Nitrogen is compressed to 30 bar prior to export to the ammonia making plant. The purpose of the water electrolysis process is to produce hydrogen for use in ammonia making. The process consists of

neg: Nitrososphaera gargensis humid habitats. Spang et al. elucidated, in 2012, the notable similarities between "N. gargensis" and "N. viennensis" through their nitrification ability and PHA (putatively polyhydroxybutyrate) production along with other elements. As a chemolithoautotroph, "Nitrososphaera gargensis" performs aerobic oxidation of ammonia to nitrite and breaks down cyanate for energy. "N. gargensis" also encompasses a flexible carbon metabolism, allowing for the uptake of organic material. Nitrification, the process of oxidizing ammonia to nitrate, is a significant step in the nitrogen cycle. Since nitrogen is limited in marine environments, the recent discovery of ammonia-oxidizing archaea proves to be an active source of study

neg: Ammonia contribution to the greenhouse effect of CFCs and HFCs in current use, if vented, would match that of all CO in the atmosphere. Ammonia is used to scrub SO from the burning of fossil fuels, and the resulting product is converted to ammonium sulfate for use as fertilizer. Ammonia neutralizes the nitrogen oxide (NO) pollutants emitted by diesel engines. This technology, called SCR (selective catalytic reduction), relies on a vanadia-based catalyst. Ammonia may be used to mitigate gaseous spills of phosgene. The raw energy density of liquid ammonia is 11.5 MJ/L, which is about a third that of diesel. Although

neg: Nitrospira moscoviensis Urease encoding genes function by catalyzing urea hydrolysis to form ammonia and carbamate. "Nitrospira moscoviensis" grows in temperatures from 33 to 40 °C and pH 7.6-8.0 with an optimal nitrite concentration of 0.35 nM. "Nitrospira moscoviensis" plays a key role in the two-step Nitrogen Cycle process. The first step of Nitrification requires an ammonia-oxidizing bacterium (AOB) or ammonia-oxidizing archaeon (AOA) followed by a nitrite-oxidizing bacterium (NOB). The unique capability of "N. moscoviensis" to cleave urea into ammonia and carbon dioxide allows for a symbiotic relationship with ammonia-oxidizing microorganisms (AOM) that lack this urease-production ability also known as negative AOM. A

neg: Argininemia of reactions that occurs in liver cells(hepatocytes). This cycle processes excess nitrogen, generated when protein is used by the body, making urea that is excreted via the kidneys. The "ARG1" gene provides instructions for making an enzyme called arginase, this enzyme controls the last steps of the urea cycle, which produces urea by extracting nitrogen from arginine. In people with arginase deficiency, arginase is missing, and arginine is not broken down properly. consequently, urea cannot be produced and excess nitrogen accumulates in the blood in the form of ammonia. Ammonia and arginine are thought to cause neurological problems and other

neg: Nitrogen cycle "Azotobacter". Symbiotic nitrogen-fixing bacteria such as "Rhizobium" usually live in the root nodules of legumes (such as peas, alfalfa, and locust trees). Here they form a mutualistic relationship with the plant, producing ammonia in exchange for carbohydrates. Because of this relationship, legumes will often increase the nitrogen content of nitrogen-poor soils. A few non-legumes can also form such symbioses. Today, about 30% of the total fixed nitrogen is produced industrially using the Haber-Bosch process, which uses high temperatures and pressures to convert nitrogen gas and a hydrogen source (natural gas or petroleum) into ammonia. Plants can absorb nitrate or ammonium

neg: Carbamoyl phosphate synthetase I deficiency urea that is excreted by the kidneys. In carbamoyl phosphate synthetase I deficiency, the enzyme that regulates the urea cycle is damaged or missing. The urea cycle cannot proceed normally, and nitrogen accumulates in the bloodstream in the form of ammonia. Ammonia is especially damaging to the nervous system, and excess ammonia causes neurological problems and other signs and symptoms of carbamoyl phosphate synthetase I deficiency. Depending on clinical status and the blood ammonia level, the logical first step is to reduce protein intake and to attempt to maintain energy intake. Initiate intravenous infusion of 10% glucose (or higher, if

neg: Non-protein nitrogen Non-protein nitrogen Non-protein nitrogen (or NPN) is a term used in animal nutrition to refer collectively to components such as urea, biuret, and ammonia, which are not proteins but can be converted into proteins by microbes in the ruminant stomach. Due to their lower cost compared to plant and animal proteins their inclusion in a diet can result in economic gain, but at too high levels cause a depression in growth and possible ammonia toxicity (microbes convert NPN to ammonia first before using that to make protein.) NPN can also be used to artificially raise crude protein values, which are

neg: Sewage treatment supplies. Different treatment processes are required to remove nitrogen and phosphorus. Nitrogen is removed through the biological oxidation of nitrogen from ammonia to nitrate (nitrification), followed by denitrification, the reduction of nitrate to nitrogen gas. Nitrogen gas is released to the atmosphere and thus removed from the water. Nitrification itself is a two-step aerobic process, each step facilitated by a different type of bacteria. The oxidation of ammonia (NH) to nitrite (NO) is most often facilitated by "Nitrosomonas" spp. ("nitroso" referring to the formation of a nitroso functional group). Nitrite oxidation to nitrate (NO), though traditionally believed to be facilitated

neg: Urea from ingested food that are not used for the synthesis of proteins and other biological substances — or produced from catabolism of muscle protein — are oxidized by the body as an alternative source of energy, yielding urea and carbon dioxide. The oxidation pathway starts with the removal of the amino group by a transaminase; the amino group is then fed into the urea cycle. The first step in the conversion of amino acids from protein into metabolic waste in the liver is removal of the alpha-amino nitrogen, which results in ammonia. Because ammonia is toxic, it is excreted immediately

neg: Microbiology of oxygen minimum zones at the bottom of the series are the iron and sulfate reducers. the utilization of these chemical species by microbes plays an important role in their biogeochemical cycling in the world's oceans. Denitrification is the reduction of nitrate and nitrite to the gaseous form of nitrogen, including the greenhouse gas nitrous oxide, that is released back into the atmosphere. Denitrification closes the nitrogen cycle by reducing the nitrogen available in organic matter fixed by phytoplankton at the surface ocean. OMZs are known for the role in the global nitrogen cycle, where the different chemical species of nitrogen and different microbes

neg: Bacterioplankton nitrogen metabolism strategies employed by bacterioplankton. Starting with molecular nitrogen in the atmosphere (N), which is fixed by diazatrophs such as trichodesmium into usable forms like ammonia (NH). This ammonia can then be assimilated into organic matter like amino and nucleic acids, by both photoautrophic and heterotrophic plankton, it can also be nitrified to NO for energy production by nitrifying bacteria. Finally the use of NO or NO as terminal electron acceptors reduces the nitrogen back into N which is then released back into the atmosphere thus closing the cycle. Another important process involved in the regeneration of atmospheric N

neg: Citrullinemia is the most common form of the disorder, affecting about one in 57,000 births worldwide. Mutations in the "ASS" gene cause type I citrullinemia. The enzyme made by this gene, argininosuccinate synthetase (), is responsible for one step of the urea cycle. Mutations in the "ASS" gene reduce the activity of the enzyme, which disrupts the urea cycle and prevents the body from processing nitrogen effectively. Excess nitrogen, in the form of ammonia, and other byproducts of the urea cycle, accumulate in the bloodstream, leading to the characteristic features of type I citrullinemia. The symptoms of type II citrullinemia (

neg: Canaline the canaline-urea cycle (analogous to the ornithine-urea cycle) is formed. Every time a canavanine molecule runs through the canaline-urea cycle, the two terminal nitrogen atoms are released as urea. Urea is an important by-product of this reaction sequence because it makes ammonicial ammonia (urease-mediated) that is available to support intermediary nitrogen metabolism. -Canaline can be reductively cleaved to -homoserine, a non-protein amino acid of great importance in the formation of a host of essential amino acids. In this way, the third nitrogen atom of canavanine enters into the reactions of nitrogen metabolism of the plant. As homoserine, its carbon skeleton

neg: Legume within root nodules of their root systems. (Plants belonging to the genus Styphnolobium are one exception to this rule.) These bacteria have the special ability of fixing nitrogen from atmospheric, molecular nitrogen (N) into ammonia (NH). The chemical reaction is: Ammonia is then converted to another form, ammonium (NH), usable by (some) plants by the following reaction: This arrangement means that the root nodules are sources of nitrogen for legumes, making them relatively rich in plant proteins. All proteins contain nitrogenous amino acids. Nitrogen is therefore a necessary ingredient in the production of proteins. Hence, legumes are among the best

neg: Soil by their incorporation into the microbes' living cells, where it is temporarily sequestered in the form of amino acids and protein. Nitrate may also be lost from the soil when bacteria metabolise it to the gases N and NO. The loss of gaseous forms of nitrogen to the atmosphere due to microbial action is called "denitrification". Nitrogen may also be "leached" from the soil if it is in the form of nitrate or lost to the atmosphere as ammonia due to a chemical reaction of ammonium with alkaline soil by way of a process called "volatilisation". Ammonium may also be

neg: Argininosuccinic aciduria cycle is a sequence of reactions in the cells of the liver. It processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. In argininosuccinic aciduria, the enzyme argininosuccinate lyase, involved in the conversion of arginino succinate to arginine within the urea cycle, is damaged or missing. The urea cycle cannot proceed normally, and nitrogen accumulates in the bloodstream in the form of ammonia. Ammonia is especially damaging to the nervous system, so argininosuccinic aciduria causes neurological problems as well as eventual damage to the liver. This

neg: Reactive nitrogen Reactive nitrogen Reactive nitrogen ("Nr") is a term used for a variety of nitrogen compounds that support growth directly or indirectly. Representative species include the gases nitrogen oxides (NO), ammonia (NH), nitrous oxide (NO), as well as the anion nitrate (NO). Most of these species are the result of intensive farming, especially the (mis)use of fertilizers. Although required for life, nitrogen is stored in the biosphere in an unreactive ("unfixed") form N, which supports on a few life forms. Reactive nitrogen is however "fixed" and is readily converted into protein, which supports life, leading to depletion of oxygen in fresh

neg: Reactive nitrogen waters by eutrophication. In the environmental context, reactive nitrogen compounds include the following classes: All of these compounds enter into the nitrogen cycle. As a consequence, an excess of Nr can affect the environment relatively quickly. This also means that nitrogen-related problems need to be looked at in an integrated manner. Reactive nitrogen Reactive nitrogen ("Nr") is a term used for a variety of nitrogen compounds that support growth directly or indirectly. Representative species include the gases nitrogen oxides (NO), ammonia (NH), nitrous oxide (NO), as well as the anion nitrate (NO). Most of these species are the result of

neg: Microbiologically induced calcite precipitation the nitrogen cycle and the sulfur cycle. Three different pathways can be involved in the nitrogen cycle: ammonification of amino acids, dissimilatory reduction of nitrate, and degradation of urea or uric acid. In sulfur cycle, bacteria follow the dissimilatory reduction of sulfate. The microbial urease catalyzes the hydrolysis of urea into ammonium and carbonate. One mole of urea is hydrolyzed intracellularly to 1 mol of ammonia and 1 mole of Carbamic acid (1), which spontaneously hydrolyzes to form an additional 1 mole of ammonia and carbonic acid (2). CO(NH) + HO ---> NHCOOH + NH (1) NHCOOH + HO --->

neg: Nitrogen cycle of ammonium to nitrate is performed primarily by soil-living bacteria and other nitrifying bacteria. In the primary stage of nitrification, the oxidation of ammonium (NH) is performed by bacteria such as the "Nitrosomonas" species, which converts ammonia to nitrites (). Other bacterial species such as "Nitrobacter", are responsible for the oxidation of the nitrites () into nitrates (). It is important for the ammonia () to be converted to nitrates or nitrites because ammonia gas is toxic to plants. Due to their very high solubility and because soils are highly unable to retain anions, nitrates can enter groundwater. Elevated nitrate

neg: Nitrogen cycle is eaten, respired, delivered to the water as ammonia, and re-incorporated into organic matter by phytoplankton it is considered recycled/regenerated production.New production is an important component of the marine environment. One reason is that only continual input of new nitrogen can determine the total capacity of the ocean to produce a sustainable fish harvest. Harvesting fish from regenerated nitrogen areas will lead to a decrease in nitrogen and therefore a decrease in primary production. This will have a negative effect on the system. However, if fish are harvested from areas of new nitrogen the nitrogen will be replenished. As a

neg: Liquid nitrogen wash a so-called nitrogen wash column, the impurities carbon monoxide, argon and methane are washed out of the synthesis gas by means of this liquid nitrogen. These impurities are dissolved together with a small part of hydrogen and leave the column as the bottom stream. The purified gas leaves the column at the top. The now purified synthesis gas is warmed up and is mixed with the required amount of gaseous high pressure nitrogen in order to achieve the hydrogen to nitrogen ratio of 3 to 1, and can then be routed to the ammonia synthesis. At operating pressures higher than

neg: Sodium azide bonds to each terminal nitrogen center. The common synthesis method is the "Wislicenus process," which proceeds in two steps from ammonia. In the first step, ammonia is converted to sodium amide: The sodium amide is subsequently combined with nitrous oxide: These reactions are the basis of the industrial route, which produced about 250 tons/y in 2004, with production increasing owing to the popularization of airbags. Curtius and Thiele developed another production process where a nitrite ester is converted to sodium azide using hydrazine. This method is suited for laboratory preparation of sodium azide: Alternatively the salt can be obtained by

neg: Non-protein nitrogen measured based on nitrogen content, as protein is about 16% nitrogen, but, for example, urea is 47% nitrogen. The source of NPN is typically a chemical feed additive, or sometimes chicken waste and cattle manure. Non-protein nitrogen Non-protein nitrogen (or NPN) is a term used in animal nutrition to refer collectively to components such as urea, biuret, and ammonia, which are not proteins but can be converted into proteins by microbes in the ruminant stomach. Due to their lower cost compared to plant and animal proteins their inclusion in a diet can result in economic gain, but at too high

neg: Ammonium dihydrogen phosphate °C, when it decomposes into gaseous ammonia and molten phosphoric acid . At 125 °C the partial pressure of ammonia is 0.05 mm Hg. A solution of stoichometric monoammonium phosphate is acidic (pH 4.7 at 0.1% concentration, 4.2 at 5%). Monoammonium phosphate is industrially prepared by the exothermic reaction of phosphoric acid and ammonia in the correct proportions: Crystalline MAP then precipitates. The largest use of monoammonium phosphate by weight is in agriculture, as an ingredient of fertilizers. It supplies soil with the elements nitrogen and phosphorus in a form usable by plants. Its NPK label is 12-61-0 (12-27-0), meaning

neg: Dinitrogen tetroxide a weak bond, since it is significantly longer than the average N-N single bond length of 1.45Å. Unlike NO, NO is diamagnetic since it has no unpaired electrons. The liquid is also colorless but can appear as a brownish yellow liquid due to the presence of NO according to the following equilibrium: Higher temperatures push the equilibrium towards nitrogen dioxide. Inevitably, some dinitrogen tetroxide is a component of smog containing nitrogen dioxide. Nitrogen tetroxide is made by the catalytic oxidation of ammonia: steam is used as a diluent to reduce the combustion temperature. In the first step, the ammonia is

neg: Nitrogen cycle from the soil via their root hairs. If nitrate is absorbed, it is first reduced to nitrite ions and then ammonium ions for incorporation into amino acids, nucleic acids, and chlorophyll. In plants that have a symbiotic relationship with rhizobia, some nitrogen is assimilated in the form of ammonium ions directly from the nodules. It is now known that there is a more complex cycling of amino acids between "Rhizobia" bacteroids and plants. The plant provides amino acids to the bacteroids so ammonia assimilation is not required and the bacteroids pass amino acids (with the newly fixed nitrogen) back to

neg: Protein (nutrient) process to individual amino acids, which are then absorbed. When amino acids are in excess of needs, the liver takes up the amino acids and deaminates them, a process converting the nitrogen from the amino acids into ammonia, further processed in the liver into urea via the urea cycle. Excretion of urea occurs via the kidneys. Other parts of the amino acid molecules can be converted into glucose and used for fuel. When food protein intake is periodically high or low, the body tries to keep protein levels at an equilibrium by using the "labile protein reserve" to compensate for

neg: Human impact on the nitrogen cycle progress has been made in determining the relative importance of Nr accumulation and denitrification, which has been mainly due to a lack of integration among scientific disciplines. Most Nr applied to global agroecosystems cascades through the atmosphere and aquatic and terrestrial ecosystems until it is converted to N, primarily through denitrification. Although terrestrial denitrification produces gaseous intermediates (nitric oxide [NO] and nitrous oxide [NO]), the last step—microbial production of N— is critical because atmospheric N is a sink for Nr. Many studies have clearly demonstrated that managed buffer strips and wetlands can remove significant amounts of nitrate (NO) from agricultural

neg: Bis(dinitrogen)bis(1,2-bis(diphenylphosphino)ethane)molybdenum(0) Mo(N)(DPPE) involved a reduction of molybdenum(III) acetylacetonate with triethylaluminum in the presence of dppe and nitrogen. A higher yielding synthesis involves a four-step process. In the first step, molybdenum(V) chloride is reduced by acetonitrile (CHCN) to give [MoCl(CHCN)]. Acetonitrile is displaced by tetrahydrofuran (THF) to give [MoCl(thf)]. This Mo(IV) compound is reduced by tin powder to [MoCl(thf)]. The desired compound is formed in the presence of nitrogen gas, dppe ligand, and magnesium turnings as the reductant: The terminal nitrogen is susceptible to electrophilic attack, allowing for the fixation of nitrogen to ammonia in the presence of acid. In this way,

neg: Community aquarium adapt to brackish water, most cannot. The most deadly chemical in aquarium water is ammonia, produced from fish excretions. It is important to test for ammonia, since it is a chemical precursor of nitrites and nitrates, also harmful to fish. Ammonia is removed from the water through the nitrogen cycle, which takes place within the aquarium filter, which takes a few weeks to start processing the ammonia. The processed ammonia is converted to nitrite, which is then processed to nitrate. Weekly water changes (25% of aquarium volume), while vacuuming debris from the bottom of the tank, can solve this problem

neg: Sequencing batch reactor oxygen environment, now start to use oxidized nitrogen instead of oxygen gas (as an alternate terminal electron acceptor) and convert the nitrogen to a gaseous state, as nitrogen oxides or, ideally, molecular nitrogen (dinitrogen, N) gas. This is known as denitrification. Anoxic SBR can be used for anaerobic processes, such as the removal of ammonia via Anammox, or the study of slow-growing microorganisms. In this case, the reactors are purged of oxygen by flushing with inert gas and there is no aeration. As the bacteria multiply and die, the sludge within the tank increases over time and a waste activated

neg: Hyperammonemia Hyperammonemia Hyperammonemia (or hyperammonaemia) is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary. Ammonia is a substance that contains nitrogen. It is a product of the catabolism of protein. It is converted to the less toxic substance urea prior to excretion in urine by the kidneys. The metabolic pathways that synthesize urea involve reactions that start in the mitochondria and then move into the cytosol. The process is known as the urea cycle, which comprises several enzymes

neg: Nitrogen a reinforced concrete beam immediately below it, and blow the walls of the laboratory 0.1–0.2 m off their foundations. Liquid nitrogen readily evaporates to form gaseous nitrogen, and hence the precautions associated with gaseous nitrogen also apply to liquid nitrogen. For example, oxygen sensors are sometimes used as a safety precaution when working with liquid nitrogen to alert workers of gas spills into a confined space. Vessels containing liquid nitrogen can condense oxygen from air. The liquid in such a vessel becomes increasingly enriched in oxygen (boiling point −183 °C, higher than that of nitrogen) as the nitrogen evaporates, and

neg: Pressure swing adsorption sieve to produce nitrogen at a purity of approximately 98%; in the second step this nitrogen is forced to pass into a second carbon molecular sieve and the nitrogen gas reaches a final purity up to 99.999%. The purge gas from the second step is recycled and partially used as feed gas in the first step. In addition, the purge process is supported by active evacuation for better performance in the next cycle. The goals of both of these changes is to improve efficiency over a conventional PSA process. The DS-PSA is also applied to up levels oxygen concentration in

neg: Constructed wetland nitrogen cycle is completed as follows: ammonia in the wastewater is converted to ammonium ions; the aerobic bacterium "Nitrosomonas" sp. oxidizes ammonium to nitrite; the bacterium "Nitrobacter" sp. then converts nitrite to nitrate. Under anaerobic conditions, nitrate is reduced to relatively harmless nitrogen gas that enters the atmosphere. Nitrification is the biological conversion of organic and inorganic nitrogenous compounds from a reduced state to a more oxidized state, based on the action of two different bacteria types. Nitrification is strictly an aerobic process in which the end product is nitrate (). The process of nitrification oxidizes ammonium (from the wastewater)

neg: Ferritic nitrocarburizing to generate ionized molecules of the gas around the surface to diffuse the nitrogen and carbon into the workpiece. Such highly active gas with ionized molecules is called plasma, naming the technique. The gas used for plasma nitriding is usually pure nitrogen, since no spontaneous decomposition is needed (as is the case of gaseous ferritic nitrocarburizing with ammonia). Due to the relatively low temperature range ( to ) generally applied during plasma-assisted ferritic nitrocarburizing and gentle cooling in the furnace, the distortion of workpieces can be minimized. Stainless steel workpieces can be processed at moderate temperatures (like ) without the

neg: Cytochrome c nitrite reductase Cytochrome c nitrite reductase Cytochrome "c" nitrite reductase (ccNiR) () is a bacterial enzyme that catalyzes the six electron reduction of nitrite to ammonia; an important step in the biological nitrogen cycle. The enzyme catalyses the second step in the two step conversion of nitrate to ammonia, which allows certain bacteria to use nitrite as a terminal electron acceptor, rather than oxygen, during anaerobic conditions. During this process, ccNiR draws electrons from the quinol pool, which are ultimately provided by a dehydrogenase such as formate dehydrogenase or hydrogenase. These dehydrogenases are responsible for generating a proton motive force. Cytochrome "c"

neg: Pnictogen respectively. Pnictogens can react with hydrogen to form pnictogen hydrides such as ammonia. The pnictogens consist of two nonmetals (one gas, one solid), two metalloids, one metal, and one element with unknown chemical properties. All the elements in the group are solids at room temperature, except for nitrogen which is gaseous at room temperature. Nitrogen and bismuth, despite both being pnictogens, are very different in their physical properties. For instance, at STP nitrogen is a transparent nonmetallic gas, while bismuth is a silvery-white metal. The densities of the pnictogens increase towards the heavier pnictogens. Nitrogen's density is 0.001251 g/cm at

neg: Diesel exhaust U.S. 2010 emissions criteria, selective non-catalytic reduction (SNCR), and exhaust gas recirculation (EGR). Both are in the exhaust system of diesel engines, and are further designed to promote efficiency. Selective catalytic reduction (SCR) injects a reductant such as ammonia or urea — the latter aqueous, where it is known as diesel exhaust fluid, DEF) — into the exhaust of a diesel engine to convert nitrogen oxides (NO) into gaseous nitrogen and water. SNCR systems have been prototyped that reduce 90% of the NO in the exhaust system, with commercialized systems being somewhat lower. SCR systems do not necessarily need particulate

neg: Alpha-Ketoglutaric acid facilitate reactions. Another function is to combine with nitrogen released in the cell, therefore preventing nitrogen overload. α-Ketoglutarate is one of the most important nitrogen transporters in metabolic pathways. The amino groups of amino acids are attached to it (by transamination) and carried to the liver where the urea cycle takes place. α-Ketoglutarate is transaminated, along with glutamine, to form the excitatory neurotransmitter glutamate. Glutamate can then be decarboxylated (requiring vitamin B) into the inhibitory neurotransmitter GABA. It is reported that high ammonia and/or high nitrogen levels may occur with high protein intake, excessive aluminum exposure, Reye's syndrome, cirrhosis, and

neg: Nitrification water. In distribution systems where chloramines are used as the secondary disinfectant, the presence of free ammonia can act as a substrate for ammonia-oxidizing microorganisms. The associated reactions can lead to the depletion of the disinfectant residual in the system. The addition of chlorite ion to chloramine-treated water has been shown to control nitrification. Together with ammonification, nitrification forms a mineralization process that refers to the complete decomposition of organic material, with the release of available nitrogen compounds. This replenishes the nitrogen cycle. Nitrification is a process of nitrogen compound oxidation (effectively, loss of electrons from the nitrogen atom to

neg: Nitriding three main methods used are: "gas nitriding", "salt bath nitriding", and "plasma nitriding". In gas nitriding the donor is a nitrogen rich gas, usually ammonia (NH), which is why it is sometimes known as "ammonia nitriding". When ammonia comes into contact with the heated work piece it dissociates into nitrogen and hydrogen. The nitrogen then diffuses onto the surface of the material creating a nitride layer. This process has existed for nearly a century, though only in the last few decades has there been a concentrated effort to investigate the thermodynamics and kinetics involved. Recent developments have led to a

neg: Nitrogen cycle ammonia being introduced at lower depths below the euphotic zone. Bacteria are able to convert ammonia to nitrite and nitrate but they are inhibited by light so this must occur below the euphotic zone. Ammonification or Mineralization is performed by bacteria to convert organic nitrogen to ammonia. Nitrification can then occur to convert the ammonium to nitrite and nitrate. Nitrate can be returned to the euphotic zone by vertical mixing and upwelling where it can be taken up by phytoplankton to continue the cycle. N can be returned to the atmosphere through denitrification. Ammonium is thought to be the preferred

neg: Nitrogen triiodide NI is pyramidal (C molecular symmetry), as are the other nitrogen trihalides and ammonia. The material that is usually called "nitrogen triiodide" is prepared by the reaction of iodine with ammonia. When this reaction is conducted at low temperatures in anhydrous ammonia, the initial product is NI · (NH), but this material loses some ammonia upon warming to give the 1:1 adduct NI · NH. This adduct was first reported by Bernard Courtois in 1812, and its formula was finally determined in 1905 by Oswald Silberrad. Its solid state structure consists of chains of -NI-I-NI-I-NI-I-... Ammonia molecules are situated between

neg: Argininosuccinate lyase arginine product, some mutagenesis studies show serine 283 may be involved. Ammonia (NH) is a toxic substance for many aerobic organisms and must be excreted. Some aquatic organisms release the toxin right directly into their environment, while other ureotelic species must convert their toxic nitrogen waste into non-toxic components, like uric acid or urea, through a series of catalyzed steps better known as the urea cycle. ASL catalyzes the fourth step in the cycle, following the action of argininosuccinate synthetase (ASS) in the liver cytosol. While ASS catalyzes the formation of argininosuccinate from citrulline and aspartate, ASL breaks the newly

neg: Nitrogen cycle contributor, but so are biofuels and even the burning of hydrogen. However, the rate that hydrogen is directly injected into the combustion chambers of internal combustion engines can be controlled to prevent the higher combustion temperatures that produce NO. Ammonia and nitrous oxides actively alter atmospheric chemistry. They are precursors of tropospheric (lower atmosphere) ozone production, which contributes to smog and acid rain, damages plants and increases nitrogen inputs to ecosystems. Ecosystem processes can increase with nitrogen fertilization, but anthropogenic input can also result in nitrogen saturation, which weakens productivity and can damage the health of plants, animals, fish, and

neg: Orotic acid inherited and the most common urea cycle disorder, excess carbamoyl phosphate is converted into orotic acid. This leads to an increased serum ammonia level, increased serum and urinary orotic acid levels and a decreased serum blood urea nitrogen level. This also leads to an increased urinary orotic acid excretion, because the orotic acid is not being properly utilized and must be eliminated. The hyperammonemia depletes alpha-ketoglutarate leading to the inhibition of the tricarboxylic acid cycle (TCA) decreasing adenosine triphosphate (ATP) production. Orotic aciduria is a cause of megaloblastic anaemia. Orotic acid Orotic acid is a heterocyclic compound and an acid;

neg: Liquid nitrogen wash water into hydrogen also produces carbon dioxide, usually this is removed in an acid gas scrubbing process together with other sour gases as e.g. hydrogen sulfide (e.g. in a Rectisol Wash Unit). The Liquid Nitrogen Wash consists of The name Liquid Nitrogen Wash is a little misleading, since no liquid nitrogen is supplied from outside to be used for scrubbing, but gaseous high pressure nitrogen, supplied by the Air separation Unit that usually also provides the oxygen for the upstream Partial Oxidation. This gaseous high pressure nitrogen is partially liquefied in the process and is used as washing agent. In

neg: Soil biology anaerobes, or facultatively anaerobes (can alter between the oxygen dependent and oxygen independent types of metabolisms), including "Achromobacter" and "Pseudomonas". The purification process caused by oxygen-free conditions converts nitrates and nitrites in soil into nitrogen gas or into gaseous compounds such as nitrous oxide or nitric oxide. In excess, denitrification can lead to overall losses of available soil nitrogen and subsequent loss of soil fertility. However, fixed nitrogen may circulate many times between organisms and the soil before denitrification returns it to the atmosphere. The diagram above illustrates the nitrogen cycle. Actinobacteria are critical in the decomposition of organic matter

neg: Selective catalytic reduction Protection Agency (EPA) standards, but in July 2012 Navistar announced it would be pursuing SCR technology for its engines, except on the MaxxForce 15 which was to be discontinued. Caterpillar had ultimately decided to exit the on-highway engine business prior to implementation of these requirements. BMW, Daimler AG, and Volkswagen have used SCR technology in some of their passenger diesel cars. Selective catalytic reduction Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen () , and water (). A gaseous reductant, typically anhydrous ammonia, aqueous

neg: Metabolic waste is. Ammonotelism is the excretion of ammonia and ammonium ions. Ammonia (NH) forms with the oxidation of amino groups.(-NH), which are removed from the proteins when they convert into carbohydrates. It is a very toxic substance to tissues and extremely soluble in water. Only one nitrogen atom is removed with it. A lot of water is needed for the excretion of ammonia, about 0.5 L of water is needed per 1 g of nitrogen to maintain ammonia levels in the excretory fluid below the level in body fluids to prevent toxicity. Thus, the marine organisms excrete ammonia directly into the

neg: Nitrosomonas by oxidizing ammonia (the other product of urease) to nitrite. This feature may explain enhanced growth of AOB in the presence of urea in acidic environments. Some sources regard Nitrobacteraceae to be the family of the genus "Nicosomonas". Nitrosomonas "Nitrosomonas" is a genus of Gram-negative rod-shaped chemoautotrophic bacteria. This organism oxidizes ammonia into nitrite as a metabolic process. "Nitrosomonas" are useful in bioremediation. They are important in the nitrogen cycle by increasing the availability of nitrogen to plants while limiting carbon dioxide fixation. The genus is found in soil, freshwater, and on building surfaces, especially in areas that contains high

neg: Nitrate in the Mississippi River Basin and ammonia (formula_4)) through various processes, such as fixation, ammonification, nitrification, and denitrification. Nitrogen’s impact on the environment is not solely determined on its form within the nitrogen cycle, but the overall concentration of each form. Negative effects on the environment can be observed when these different forms of nitrogen are in excess. The Environmental Protection Agency has set a maximum of 10 mg/L nitrate concentration in drinking and surface waters. When nitrogen in the form of nitrate is in excess, it can lead to a dead zone. A dead zone is a body of water that has a depleted

neg: Denitrification Denitrification Denitrification is a microbially facilitated process where nitrate is reduced and ultimately produces molecular nitrogen (N) through a series of intermediate gaseous nitrogen oxide products. Facultative anaerobic bacteria perform denitrification as a type of respiration that reduces oxidized forms of nitrogen in response to the oxidation of an electron donor such as organic matter. The preferred nitrogen electron acceptors in order of most to least thermodynamically favorable include nitrate (NO), nitrite (NO), nitric oxide (NO), nitrous oxide (NO) finally resulting in the production of dinitrogen (N) completing the nitrogen cycle. Denitrifying microbes require a very low oxygen concentration of

neg: Freshwater environmental quality parameters the proximity of humans, the largest input is from sewage whether treated or untreated. The nitrogen derives from breakdown products of proteins found in urine and faeces. These products, being very soluble, often pass through sewage treatment process and are discharged into rivers as a component of sewage treatment effluent. Nitrogen may be in the form of nitrate, nitrite, ammonia or ammonium salts or what is termed albuminoid nitrogen or nitrogen still within an organic proteinoid molecule. The differing forms of nitrogen are relatively stable in most river systems with nitrite slowly transforming into nitrate in well oxygenated rivers and

neg: Diesel exhaust fluid leads to generation of nitrogen oxides (), which are harmful pollutants, from the nitrogen in the air. Selective catalytic reduction is used to reduce the amount of released into the atmosphere. Diesel exhaust fluid (DEF) from a separate tank is injected into the exhaust pipeline, where the aqueous urea vaporizes and decomposes to form ammonia and carbon dioxide. Within the SCR catalyst, the are catalytically reduced by the ammonia () into water () and nitrogen (), which are both harmless; and these are then released through the exhaust. DEF is a 32.5% solution of urea, . When it is injected

neg: Crop rotation water provided by the plant to convert atmospheric nitrogen into ammonia, which is then converted into an organic compound that the plant can use as its nitrogen source. It therefore makes good sense agriculturally to alternate them with cereals (family Poaceae) and other plants that require nitrates. How much nitrogen made available to the plants depends on factors such as the kind of legume, the effectiveness of rhizobia bacteria, soil conditions, and the availability of elements necessary for plant food. Crop rotation is also used to control pests and diseases that can become established in the soil over time. The

neg: Pea glucose-6-phosphate dehydrogenase that affects Jews, other Middle Eastern Semitic peoples and other descendants of the Mediterranean coastal regions. In this condition, the toxic reaction to eating most, if not all, beans is hemolytic anemia, and in severe cases the released circulating free hemoglobin causes acute kidney injury. Peas, like many legumes, contain symbiotic bacteria called "Rhizobia" within root nodules of their root systems. These bacteria have the special ability of fixing nitrogen from atmospheric, molecular nitrogen (N) into ammonia (NH). The chemical reaction is: Ammonia is then converted to another form, ammonium (NH), usable by (some) plants by the following

neg: Nitrogen diatomic gas with the formula N. Dinitrogen forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids (DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many industrially important compounds, such as ammonia, nitric acid,

neg: Urea by fish, converted into uric acid by birds, and converted into urea by mammals. Ammonia (NH) is a common byproduct of the metabolism of nitrogenous compounds. Ammonia is smaller, more volatile and more mobile than urea. If allowed to accumulate, ammonia would raise the pH in cells to toxic levels. Therefore, many organisms convert ammonia to urea, even though this synthesis has a net energy cost. Being practically neutral and highly soluble in water, urea is a safe vehicle for the body to transport and excrete excess nitrogen. Urea is synthesized in the body of many organisms as part of

neg: Poultry litter a loss of profits to the grower and integrator. When broilers and turkeys are raised on litter, amendments can be used to reduce ammonia levels in the houses and improve productivity. Uric acid and organic nitrogen (N) in the bird excreta and spilled feed are converted to ammonium (NH4+) by the microbes in the litter. Ammonium, a plant-available N form, can bind to litter and also dissolve in water. Depending on the moisture content, temperature, and acidity of the litter, a portion of the ammonium will be converted into ammonia (NH3). Ammonia production is favored by high temperature and high

neg: Comammox Comammox Comammox (COMplete AMMonia OXidiser) is the name for an organism that can first convert ammonia into nitrite and then into nitrate by a process called nitrification. These two processes are commonly carried out by separate groups of microorganisms. However, complete conversion of ammonia into nitrate by a single microorganism was predicted in 2006. Almost ten years later the presence of such organisms was discovered within the "nitrospira" and the nitrogen cycle had to be updated. The genomes revealed the presence of genes necessary for ammonia oxidation (e.g. amoA gene and hao cluster). Nearly two years after the discovery of

neg: Denitrifying bacteria an aerobic respiratory process in which nitrate is converted gradually to N (NO →NO → NO → NO → N ), using nitrate reductase (Nar or Nao), nitrite reductase (Nir), nitric oxide reductase (Nor), and nitrous oxide reductase (Nos). Phylogenetic analysis revealed that aerobic denitrifiers mainly belong to α-, β- and γ-"Proteobacteria". Denitrifying bacteria use denitrification to generate ATP. The most common denitrification process is outlined below, with the nitrogen oxides being converted back to gaseous nitrogen: 2 NO + 10 e + 12 H → N + 6 HO The result is one molecule of nitrogen and six molecules