Sample records for abiotic ammonium formation
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Abiotic mechanism for the formation of atmospheric nitrous oxide from ammonium nitrate.
Rubasinghege, Gayan; Spak, Scott N; Stanier, Charles O; Carmichael, Gregory R; Grassian, Vicki H
2011-04-01
Nitrous oxide (N2O) is an important greenhouse gas and a primary cause of stratospheric ozone destruction. Despite its importance, there remain missing sources in the N2O budget. Here we report the formation of atmospheric nitrous oxide from the decomposition of ammonium nitrate via an abiotic mechanism that is favorable in the presence of light, relative humidity and a surface. This source of N2O is not currently accounted for in the global N2O budget. Annual production of N2O from atmospheric aerosols and surface fertilizer application over the continental United States from this abiotic pathway is estimated from results of an annual chemical transport simulation with the Community Multiscale Air Quality model (CMAQ). This pathway is projected to produce 9.3(+0.7/-5.3) Gg N2O annually over North America. N2O production by this mechanism is expected globally from both megacities and agricultural areas and may become more important under future projected changes in anthropogenic emissions.
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Abiotic methane formation during experimental serpentinization of olivine.
McCollom, Thomas M
2016-12-06
Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH 4 ). In many cases, the CH 4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH 4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH 4 synthesis have been observed. Here, the potential for abiotic formation of CH 4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A 13 C-labeled inorganic carbon source was used to unambiguously determine the origin of CH 4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH 4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH 4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH 4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH 4 was observed in one experiment performed under conditions that allowed an H 2 -rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH 4 .
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Shock wave synthesis of amino acids from solutions of ammonium formate and ammonium bicarbonate
Suzuki, Chizuka; Furukawa, Yoshihiro; Kobayashi, Takamichi; Sekine, Toshimori; Nakazawa, Hiromoto; Kakegawa, Takeshi
2015-07-01
The emergence of life's building blocks, such as amino acids and nucleobases, on the prebiotic Earth was a critical step for the beginning of life. Reduced species with low mass, such as ammonia, amines, or carboxylic acids, are potential precursors for these building blocks of life. These precursors may have been provided to the prebiotic ocean by carbonaceous chondrites and chemical reactions related to meteorite impacts on the early Earth. The impact of extraterrestrial objects on Earth occurred more frequently during this period than at present. Such impacts generated shock waves in the ocean, which have the potential to progress chemical reactions to form the building blocks of life from reduced species. To simulate shock-induced reactions in the prebiotic ocean, we conducted shock-recovery experiments on ammonium bicarbonate solution and ammonium formate solution at impact velocities ranging from 0.51 to 0.92 km/s. In the products from the ammonium formate solution, several amino acids (glycine, alanine, ß-alanine, and sarcosine) and aliphatic amines (methylamine, ethylamine, propylamine, and butylamine) were detected, although yields were less than 0.1 mol % of the formic acid reactant. From the ammonium bicarbonate solution, smaller amounts of glycine, methylamine, ethylamine, and propylamine were formed. The impact velocities used in this study represent minimum cases because natural meteorite impacts typically have higher velocities and longer durations. Our results therefore suggest that shock waves could have been involved in forming life's building blocks in the ocean of prebiotic Earth, and potentially in aquifers of other planets, satellites, and asteroids.
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Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei
2015-03-01
A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development.
Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming
2011-10-01
A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stresses affect LR formation. We proposed that SSA regulates LR emergence by interrupting AUX1-mediated auxin transport from shoot to root. Here, by analyzing both ABA- and auxin-related mutants, we show that AUX1 is also required for SSA-mediated suppression of primary root growth. Ammonium content in shoots was furthermore shown to increase linearly with shoot-, but not root-supplied, ammonium, suggesting it may represent the internal trigger for SSA inhibition of root development. Taken together, our data identify AUX1-mediated auxin transport as a key transmission step in the sensing of excessive ammonium exposure and its inhibitory effect on root development.
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Formation rate of ammonium nitrate in the off-gas line of SRAT and SME in DWPF
International Nuclear Information System (INIS)
Lee, L.
1992-01-01
A mathematical model for the formation rate of ammonium nitrate in the off-gas line of the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mixed Evaporator (SME) in DWPF has been developed. The formation rate of ammonium nitrate in the off-gas line depends on pH, temperature, volume and total concentration of ammonia and ammonium ion. Based on a typical SRAT and SME cycle in DWPF, this model predicts the SRAT contributes about 50 lbs of ammonium nitrate while SME contributes about 60 lbs of ammonium nitrate to the off-gas line
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Roles of abscisic acid and auxin in shoot-supplied ammonium inhibition of root system development
Li, Baohai; Li, Qing; Kronzucker, Herbert J; Shi, Weiming
2011-01-01
A plastic root system is a prerequisite for successful plant acclimation to variable environments. The normally functioning root system is the result of a complex interaction of root-borne signals and shoot-derived regulators. We recently demonstrated that AUX1, a well-studied component of auxin transport, mediates shoot-supplied ammonium (SSA) inhibition of lateral root (LR) formation in Arabidopsis. By contrast, the response did not involve ABA pathways, via which several other abiotic stre...
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Abiotic Formation of Methyl Halides in the Terrestrial Environment
Keppler, F.
2011-12-01
Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will
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Zara, Giacomo; Budroni, Marilena; Mannazzu, Ilaria; Zara, Severino
2011-12-01
Air-liquid biofilm formation appears to be an adaptive mechanism that promotes foraging of Saccharomyces cerevisiae flor strains in response to nutrient starvation. The FLO11 gene plays a central role in this phenotype as its expression allows yeast cells to rise to the liquid surface. Here, we investigated the role of ammonium depletion in air-liquid biofilm formation and FLO11 expression in a S. cerevisiae flor strain. The data obtained show that increasing ammonium concentrations from 0 to 450 m m reduce air-liquid biofilm in terms of biomass and velum formation and correlate with a reduction of FLO11 expression. Rapamycin inhibition of the TOR pathway and deletion of RAS2 gene significantly reduced biofilm formation and FLO11 expression. Taken together, these data suggest that ammonium depletion is a key factor in the induction of air-liquid biofilm formation and FLO11 expression in S. cerevisiae flor strains. Copyright © 2011 John Wiley & Sons, Ltd.
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Assessment of the potential for ammonium nitrate formation and reaction in Tank 241-SY-101
International Nuclear Information System (INIS)
Pederson, L.R.; Bryan, S.A.
1994-08-01
Two principal scenarios by which ammonium nitrate may be formed were considered: (a) precipitation of ammonium nitrate in the waste, and (b) ammonium nitrate formation via the gas phase reaction of ammonia and nitrogen dioxide. The first of these can be dismissed because ammonium ions, which are necessary for ammonium nitrate precipitation, can exist only in negligibly small concentrations in strongly alkaline solutions. Gas phase reactions between ammonia, nitrogen dioxide, and water vapor in the gas phase represent the most likely means by which ammonium nitrate aerosols could be formed in Tank 241-SY-101. Predicted ammonium nitrate formation rates are largely controlled by the concentration of nitrogen dioxide. This gas has not been detected among those gases vented from the wastes using Fourier Transform Infrared Spectrometry (FTIR) or mass spectrometry. While detection limits for nitrogen dioxide have not been established experimentally, the maximum concentration of nitrogen dioxide in the gas phase in Tank 241-SY-101 was estimated at 0.1 ppm based on calculations using the HITRAN data base and on FTIR spectra of gases vented from the wastes. At 50 C and with 100 ppm ammonia also present, less than one gram of ammonium nitrate per year is estimated to be formed in the tank. To date, ammonium nitrate has not been detected on HEPA filters in the ventilation system, so any quantity that has been formed in the tank must be quite small, in good agreement with rate calculations. The potential for runaway exothermic reactions involving ammonium nitrate in Tank 241-SY-101 is minimal. Dilution by non-reacting waste components, particularly water, would prevent hazardous exothermic reactions from occurring within the waste slurry, even if ammonium nitrate were present. 41 refs
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A significant abiotic pathway for the formation of unknown nitrogen in nature
Jokic, A.; Schulten, H.-R.; Cutler, J. N.; Schnitzer, M.; Huang, P. M.
2004-03-01
The global nitrogen cycle is of prime importance in natural ecosystems. However, the origin and nature of up to one-half of total soil N remains obscure despite all attempts at elucidation. Our data provide, for the first time, unequivocal evidence that the promoting action of Mn (IV) oxide on the Maillard reaction (sugar-amino acid condensation) under ambient conditions results in the abiotic formation of heterocyclic N compounds, which are often referred to as unknown nitrogen, and of amides which are apparently the dominant N moieties in nature. The information presented is of fundamental significance in understanding the role of mineral colloids in abiotic transformations of organic N moieties, the incorporation of N in the organic matrix of fossil fuels, and the global N cycle.
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International Nuclear Information System (INIS)
El-Mamoon Yahai, M.; El-Fekey, S.A.; Abd El-Razek, A.M.
1996-01-01
Ammonium uranates (AU) were precipitated from a nuclear-pure uranyl nitrate solution using ammonia liquor. Unwashed and washed uranate samples were heated at temperatures varying between 400 and 800 C and analysed thermally and by X-ray diffraction analysis. The results indicated that amorphous uranium trioxide (A-UO 3 ) is mainly formed in absence of carried ammonium and nitrate ions, whereas deamination of the retained ammonia leads to β-UO 3 formation. The retained ammonium ions in the AU structure increased with the pH of precipitation and these ions lead to formation of two polymorphs of uranium octoxides. (orig.)
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Yan, Mi; Qi, Zhi-Fu; Li, Xiao-Dong; Hu, Yan-Jun; Chen, Tong
2014-01-01
Chlorobenzene (CBz) is the precursor of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) generated in the processes of waste incineration, and it is regarded as a good indicator of PCDD/Fs for realizing PCDD/Fs online monitoring, moreover, pentachlorobenzene (PeCBz) and Hexachlorobenzene (HxCBz) belong to Persistent Organic Pollutants (POPs). However, the emission control of CBz in waste incineration does not attract enough attention, so this study focused on the inhibition of the 3 CBz formation routes in waste combustion by ammonium sulfate and urea, including CB formation from fly ash, CB formation from 1,2-dichlorobenzene (1,2-DiCBz) and the combustion of model medical waste. The results showed that both ammonium sulfate and urea reduced CBz yield during these three thermal processes. For instance, the inhibition rates of tetrachlorobenzene (TeCBz), PeCBz and HxCBz were 66.8%, 57.4% and 50.4%, respectively, when 1% urea was co-combusted with medical waste. By comparing the effect of ammonium sulfate and urea on CBz formation by three routes, urea was considered as a comparatively stable inhibitor for CBz.
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Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds
Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.
2012-04-01
Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC
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Formation and decomposition of ammoniated ammonium ions
International Nuclear Information System (INIS)
Ikezoe, Yasumasa; Suzuki, Kazuya; Nakashima, Mikio; Yokoyama, Atsushi; Shiraishi, Hirotsugu; Ohno, Shin-ichi
1998-09-01
Structures, frequencies, and chemical reactions of ammoniated ammonium ions (NH 4 + .nNH 3 ) were investigated theoretically by ab initio molecular orbital calculations and experimentally by observing their formation and decomposition in a corona discharge-jet expansion process. The ab initio calculations were carried out using a Gaussian 94 program, which gave optimized structures, binding energies and harmonic vibrational frequencies of NH 4 + .nNH 3 . Effects of discharge current, the reactant gas and the diameter of the gas expanding pinhole were examined on the size n distribution of NH 4 + .nNH 3 . The results indicated that the cluster ion, in the jet expansion process, grew in size mostly equal to or less than one unit under experimental conditions employed. Effects of discharge current, pinhole diameter, flight time in vacuum and cluster size were examined on the decomposition rate of cluster ions formed. In our experimental conditions, the internal energies of cluster ions were mainly determined through exo- and/or endo-thermic reactions involved in the cluster formation process. (author)
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Shuai, Yanhua; Etiope, Giuseppe; Zhang, Shuichang; Douglas, Peter M. J.; Huang, Ling; Eiler, John M.
2018-01-01
Abiotic hydrocarbon gas, typically generated in serpentinized ultramafic rocks and crystalline shields, has important implications for the deep biosphere, petroleum systems, the carbon cycle and astrobiology. Distinguishing abiotic gas (produced by chemical reactions like Sabatier synthesis) from biotic gas (produced from degradation of organic matter or microbial activity) is sometimes challenging because their isotopic and molecular composition may overlap. Abiotic gas has been recognized in numerous locations on the Earth, although there are no confirmed instances where it is the dominant source of commercially valuable quantities in reservoir rocks. The deep hydrocarbon reservoirs of the Xujiaweizi Depression in the Songliao Basin (China) have been considered to host significant amounts of abiotic methane. Here we report methane clumped-isotope values (Δ18) and the isotopic composition of C1-C3 alkanes, CO2 and helium of five gas samples collected from those Xujiaweizi deep reservoirs. Some geochemical features of these samples resemble previously suggested identifiers of abiotic gas (13C-enriched CH4; decrease in 13C/12C ratio with increasing carbon number for the C1-C4 alkanes; abundant, apparently non-biogenic CO2; and mantle-derived helium). However, combining these constraints with new measurements of the clumped-isotope composition of methane and careful consideration of the geological context, suggests that the Xujiaweizi depression gas is dominantly, if not exclusively, thermogenic and derived from over-mature source rocks, i.e., from catagenesis of buried organic matter at high temperatures. Methane formation temperatures suggested by clumped-isotopes (167-213 °C) are lower than magmatic gas generation processes and consistent with the maturity of local source rocks. Also, there are no geological conditions (e.g., serpentinized ultramafic rocks) that may lead to high production of H2 and thus abiotic production of CH4 via CO2 reduction. We propose
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Yang, Zhen; Kong, Fanxiang
2013-07-01
Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.
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Energy Technology Data Exchange (ETDEWEB)
Yang Zhiquan [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China); Zhou Shaoqi, E-mail: fesqzhou@scut.edu.cn [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China); State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, Guangdong 510640 (China); Sun Yanbo [College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006 (China)
2009-09-30
A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L{sup -1} respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L{sup -1}, respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the
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International Nuclear Information System (INIS)
Yang Zhiquan; Zhou Shaoqi; Sun Yanbo
2009-01-01
A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L -1 respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L -1 , respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic
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78 FR 42692 - Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate
2013-07-17
... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 573 [Docket No. FDA-2008-F-0151] Food Additives Permitted in Feed and Drinking Water of Animals; Ammonium Formate... and Drug Administration (FDA) is amending the regulations for food additives permitted in feed and...
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Babarro, J.M.F.; De Zwaan, A.
2002-01-01
The effect of several abiotic factors (salinity, temperature and pH) on bacterial proliferation and survival time of the sea mussel Mytilus edulis L. were studied under anoxic incubations. In addition, the presence in the incubation media of ammonium and the volatile fatty acids propionate and
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Study of organic chlorine in soils and formation in biotic and abiotic conditions
International Nuclear Information System (INIS)
Osswald, Aurelie
2016-01-01
Chlorine has long been considered as the predominantly chlorine form present in the environment. However, recent studies have shown that chlorine is retained in the soil as an organic form and is formed by a natural process of chlorination mainly from the microbial activity of the soil still poorly documented. The aim of this study is to estimate the organic and inorganic forms of chlorine in contrasting soil and highlight the evolution of these forms according to certain environmental parameters or terms of incubations and to the activity of microorganisms. For this, the organo-mineral horizons of contrasting soil were studied (i) in situ: The amounts of chlorine and physico-chemical and microbiological parameters of soil were measured; (ii) in two experimental devices incubations under different conditions. Measurements of chlorine levels between the beginning and the end of the first experiment were measured by AOX analyzer. For the second experiment, the soil was previously enriched with Na 37 Cl and 37 Cl levels were measured by HR ICP MS. Soil samples from these incubations were analyzed by Xanes spectrometry to identify the speciation of chlorine forms in soils. Soil non-extractable organic chlorine contents represent almost all of the chlorine. The parameters that influence the distribution of chlorine contents in soils correspond to vegetation cover, pH, organic carbon content and quantities of microorganisms. The chlorine contents measured by AOX analyzer and by HR ICP MS highlight an organic chlorine formation over time in relation to the microorganisms in the soil. The measures carried out by HR ICP MS show also an organic chlorine formation in abiotic conditions. Conversely, XANES spectrometry measurements have shown any organic chlorine formation. In conclusion, the parameters that influence the distribution of chlorine contents in soils have been targeted. Similarly, the microbial origin of the chlorination process has been demonstrated, although a
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Directory of Open Access Journals (Sweden)
H. Petetin
2016-08-01
Full Text Available Secondary inorganic compounds represent a major fraction of fine aerosol in the Paris megacity. The thermodynamics behind their formation is now relatively well constrained but, due to sparse direct measurements of their precursors (in particular NH3 and HNO3, uncertainties remain on their concentrations and variability as well as the formation regime of ammonium nitrate (in terms of limited species among NH3 and HNO3 in urban environments such as Paris. This study presents the first urban background measurements of both inorganic aerosol compounds and their gaseous precursors during several months within the city of Paris. Intense agriculture-related NH3 episodes are observed in spring/summer while HNO3 concentrations remain relatively low, even during summer, which leads to a NH3-rich regime in Paris. The local formation of ammonium nitrate within the city appears low, despite high NOx emissions. The data set also allows evaluating the CHIMERE chemistry-transport model (CTM. Interestingly, the rather good results obtained on ammonium nitrates hide significant errors on gaseous precursors (e.g., mean bias of −75 and +195 % for NH3 and HNO3, respectively. This leads to a misrepresentation of the nitrate formation regime through a highly underestimated gas ratio metric (introduced by Ansari and Pandis, 1998 and a much higher sensitivity of nitrate concentrations to ammonia changes. Several uncertainty sources are investigated, pointing out the importance of better assessing both NH3 agricultural emissions and OH concentrations in the future. These results remind us of the caution required when using of CTMs for emission scenario analysis, highlighting the importance of prior diagnostic and dynamic evaluations.
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Directory of Open Access Journals (Sweden)
Klaudia Borysiuk
2018-05-01
Full Text Available Nitrate (NO3– and ammonium (NH4+ are prevalent nitrogen (N sources for plants. Although NH4+ should be the preferred form of N from the energetic point of view, ammonium nutrition often exhibits adverse effects on plant physiological functions and induces an important growth-limiting stress referred as ammonium syndrome. The effective incorporation of NH4+ into amino acid structures requires high activity of the mitochondrial tricarboxylic acid cycle and the glycolytic pathway. An unavoidable consequence of glycolytic metabolism is the production of methylglyoxal (MG, which is very toxic and inhibits cell growth in all types of organisms. Here, we aimed to investigate MG metabolism in Arabidopsis thaliana plants grown on NH4+ as a sole N source. We found that changes in activities of glycolytic enzymes enhanced MG production and that markedly elevated MG levels superseded the detoxification capability of the glyoxalase pathway. Consequently, the excessive accumulation of MG was directly involved in the induction of dicarbonyl stress by introducing MG-derived advanced glycation end products (MAGEs to proteins. The severe damage to proteins was not within the repair capacity of proteolytic enzymes. Collectively, our results suggest the impact of MG (mediated by MAGEs formation in proteins in the contribution to NH4+ toxicity symptoms in Arabidopsis.
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Borysiuk, Klaudia; Ostaszewska-Bugajska, Monika; Vaultier, Marie-Noëlle; Hasenfratz-Sauder, Marie-Paule; Szal, Bożena
2018-01-01
Nitrate (NO3–) and ammonium (NH4+) are prevalent nitrogen (N) sources for plants. Although NH4+ should be the preferred form of N from the energetic point of view, ammonium nutrition often exhibits adverse effects on plant physiological functions and induces an important growth-limiting stress referred as ammonium syndrome. The effective incorporation of NH4+ into amino acid structures requires high activity of the mitochondrial tricarboxylic acid cycle and the glycolytic pathway. An unavoidable consequence of glycolytic metabolism is the production of methylglyoxal (MG), which is very toxic and inhibits cell growth in all types of organisms. Here, we aimed to investigate MG metabolism in Arabidopsis thaliana plants grown on NH4+ as a sole N source. We found that changes in activities of glycolytic enzymes enhanced MG production and that markedly elevated MG levels superseded the detoxification capability of the glyoxalase pathway. Consequently, the excessive accumulation of MG was directly involved in the induction of dicarbonyl stress by introducing MG-derived advanced glycation end products (MAGEs) to proteins. The severe damage to proteins was not within the repair capacity of proteolytic enzymes. Collectively, our results suggest the impact of MG (mediated by MAGEs formation in proteins) in the contribution to NH4+ toxicity symptoms in Arabidopsis. PMID:29881392
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Atmospheric behaviour of ammonia and ammonium
Asman, W.A.H.
1987-01-01
1.4.1 Scope of this thesis
A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid
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Microbial electricity driven anoxic ammonium removal.
Vilajeliu-Pons, Anna; Koch, Christin; Balaguer, Maria D; Colprim, Jesús; Harnisch, Falk; Puig, Sebastià
2018-03-01
Removal of nitrogen, mainly in form of ammonium (NH 4 + ), in wastewater treatment plants (WWTPs) is a highly energy demanding process, mainly due to aeration. It causes costs of about half a million Euros per year in an average European WWTP. Alternative, more economical technologies for the removal of nitrogen compounds from wastewater are required. This study proves the complete anoxic conversion of ammonium (NH 4 + ) to dinitrogen gas (N 2 ) in continuously operated bioelectrochemical systems at the litre-scale. The removal rate is comparable to conventional WWTPs with 35 ± 10 g N m -3 d -1 with low accumulation of NO 2 - , NO 3 - , N 2 O. In contrast to classical aerobic nitrification, the energy consumption is considerable lower (1.16 ± 0.21 kWh kg -1 N, being more than 35 times less than for the conventional wastewater treatment). Biotic and abiotic control experiments confirmed that the anoxic nitrification was an electrochemical biological process mainly performed by Nitrosomonas with hydroxylamine as the main substrate (mid-point potential, E ox = +0.67 ± 0.08 V vs. SHE). This article proves the technical feasibility and reduction of costs for ammonium removal from wastewater, investigates the underlying mechanisms and discusses future engineering needs. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.
Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei
2017-07-19
An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .
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Development of technology for ammonium nitrate dissociation process
International Nuclear Information System (INIS)
Zakharkin, B.S.; Varykhanov, V.P.; Kucherenko, V.S.; Solov'yeva, L.N.; Revyakin, V.V.
2000-01-01
Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate
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Zhou, Jun; Sun, Qianyu; Chen, Dan; Wang, Hongyu; Yang, Kai
2017-10-01
In this study, the hydrogenotrophic denitrifying bacterium Ochrobactrum anthropi was added in to the process of nitrate removal by starch-stabilized nanoscale zero valent iron (nZVI) to minimize undesirable ammonium. The ammonium control performance and cooperative mechanism of this combined process were investigated, and batch experiments were conducted to discuss the effects of starch-stabilized nZVI dose, biomass, and pH on nitrate reduction and ammonium control of this system. The combined system achieved satisfactory performance because the anaerobic iron corrosion process generates H 2 , which is used as an electron donor for the autohydrogenotrophic bacterium Ochrobactrum anthropi to achieve the autohydrogenotrophic denitrification process converting nitrate to N 2 . When starch-stabilized nZVI dose was increased from 0.5 to 2.0 g/L, nitrate reduction rate gradually increased, and ammonium yield also increased from 9.40 to 60.51 mg/L. Nitrate removal rate gradually decreased and ammonium yield decreased from 14.93 to 2.61 mg/L with initial OD 600 increasing from 0.015 to 0.080. The abiotic Fe 0 reduction process played a key role in nitrate removal in an acidic environment and generated large amounts of ammonium. Meanwhile, the nitrate removal rate decreased and ammonium yield also reduced in an alkaline environment.
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Directory of Open Access Journals (Sweden)
Hebert F. Culler
2014-01-01
Full Text Available The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM. Biofilm formation on abiotic surfaces occurred in 55 (60.4% of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence. This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea.
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Origin of Abiotic Methane in Submarine Hydrothermal Systems
Seewald, J. S.; German, C. R.; Grozeva, N. G.; Klein, F.; McDermott, J. M.; Ono, S.; Reeves, E. P.; Wang, D. T.
2018-05-01
Results of recent investigations into the chemical and isotopic composition of actively venting submarine hydrothermal fluids and volatile species trapped in fluid inclusions will be discussed in the context of processes responsible for abiotic CH4 formation.
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Directory of Open Access Journals (Sweden)
Xin-Yuan Sun
2015-01-01
Full Text Available The components of urinary nanocrystallites in patients with magnesium ammonium phosphate (MAP stones were analyzed by X-ray diffraction (XRD, Fourier-transform infrared (FT-IR spectrometer, high-resolution transmission electron microscopy (HRTEM, selected area electron diffraction (SAED, fast Fourier transformation (FFT, and energy-dispersive X-ray spectroscopy (EDS. The main components of the stones were MAP hexahydrate (MAP·6H2O, magnesium hydrogen phosphate trihydrate (MgHPO4·3H2O, and a small amount of calcium phosphate (CaP, while the main components of urinary nanocrystallites were MgHPO4·3H2O, CaP, and MAP monohydrate (MAP·H2O. MAP·H2O induced the formation of MAP stones as seed crystals. MgHPO4·3H2O was accompanied by the appearance of MAP·6H2O. The formation mechanism of MAP stones and influencing factors were discussed on the basis of the components of urine nanocrystallites. A model diagram of MAP stone formation was also put forward based on the results. Formation of MAP stones was closely related to the presence of high amounts of MAP crystallites in urine. Urinary crystallite condition and changes in urine components could indicate the activity of stone diseases.
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Demeestere, K; Smet, E; Van Langenhove, H; Galbacs, Z
2001-12-01
Among the physico-chemical abatement technologies, mainly acid scrubbers have been used to control NH3-emission. The disadvantage of this technique is that it yields waste water, highly concentrated in ammonia. In this report, the applicability of the magnesium ammonium phosphate (MAP) process to regenerate the liquid phase, produced by scrubbing NH3-loaded waste gases, was investigated. In the MAP process, ammonium is precipitated as magnesium ammonium phosphate, which can be used as a slow release fertilizer. The influence of a number of parameters, e.g. pH, kinetics, molar ratio NH(+)4/Mg2+/PO(3-)4 on the efficiency of the formation of MAP and on the ammonium removal efficiency was investigated. In this way, optimal conditions were determined for the precipitation reaction. Next to this, interference caused by other precipitation reactions was studied. At aqueous NH(+)4-concentrations of about 600 mg l(-1), ammonium removal efficiencies of 97% could be obtained at a molar ratio NH(+)4/Mg2+/PO(3-)4 of 1/1.5/1.5. To obtain this result, the pH was continuously adjusted to a value of 9 during the reaction. According to this study, it is obvious that the MAP-precipitation technology offers opportunities for ammonium removal from scrubbing liquids. The practical applicability of the MAP-process in waste gas treatment systems, however, should be the subject for further investigations.
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Abiotic and Biotic Formation of Amino Acids in the Enceladus Ocean.
Steel, Elliot L; Davila, Alfonso; McKay, Christopher P
2017-09-01
The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H 2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H 2 production of 0.6-34 mol/s from serpentinization, sufficient to sustain abiotic and biotic amino acid synthesis of 1.6-87 and 1-44 g/s, respectively. Two-dimensional (2D) numerical simulations of the hydrothermal vent suggest that the vent fluids could reach the ice-water boundary in less than 11-55 days for a 50 km deep ocean diluted by ambient ocean water 10 to 1. Concentrations of glycine, alanine, α-amino isobutyric acid, and glutamic acid in the plume and in the ambient ocean could all be above 0.01 μM just due to abiotic production. Biological synthesis, if occurring, could produce a maximum of 90 μM concentrations of amino acids based on a methanogenic ecosystem consuming H 2 and CO 2 . Racemization timescales in the ocean are short compared with production timescales. Thus, no enantiomeric excess is expected in the ambient ocean, and if biology is present, enantiomeric excess at the vent fluids is expected to be less than 10% in the plume. From vent H 2 concentrations of 7.8 mM (e.g., Lost City) and assuming complete H 2 use and conversion to chemical energy by methanogens, cell production is estimated. Annual biomass production in the methanogenic-based biology model is 4 × 10 4 -2 × 10 6 kg/year. This corresponds to cell concentrations ∼10 9 cells/cm 3 in the vents and ∼10 8 cells/cm 3 in the plume, and when diluted into the ambient ocean, we predict cell concentrations of 80-4250 cells/cm 3 . Key Words: Abiotic organic
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Formation of iron (hydr)oxides during the abiotic oxidation of Fe(II) in the presence of arsenate.
Song, Jia; Jia, Shao-Yi; Yu, Bo; Wu, Song-Hai; Han, Xu
2015-08-30
Abiotic oxidation of Fe(II) is a common pathway in the formation of Fe (hydr)oxides under natural conditions, however, little is known regarding the presence of arsenate on this process. In hence, the effect of arsenate on the precipitation of Fe (hydr)oxides during the oxidation of Fe(II) is investigated. Formation of arsenic-containing Fe (hydr)oxides is constrained by pH and molar ratios of As:Fe during the oxidation Fe(II). At pH 6.0, arsenate inhibits the formation of lepidocrocite and goethite, while favors the formation of ferric arsenate with the increasing As:Fe ratio. At pH 7.0, arsenate promotes the formation of hollow-structured Fe (hydr)oxides containing arsenate, as the As:Fe ratio reaches 0.07. Arsenate effectively inhibits the formation of magnetite at pH 8.0 even at As:Fe ratio of 0.01, while favors the formation of lepidocrocite and green rust, which can be latterly degenerated and replaced by ferric arsenate with the increasing As:Fe ratio. This study indicates that arsenate and low pH value favor the slow growth of dense-structured Fe (hydr)oxides like spherical ferric arsenate. With the rapid oxidation rate of Fe(II) at high pH, ferric (hydr)oxides prefer to precipitate in the formation of loose-structured Fe (hydr)oxides like lepidocrocite and green rust. Copyright © 2015 Elsevier B.V. All rights reserved.
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Directory of Open Access Journals (Sweden)
Praveen K. Sahu
2012-01-01
Full Text Available A major facilitator superfamily (MFS transporter-like open reading frame (ORF of 453 bp was identified in a pathogenic strain Acinetobacter baumannii AIIMS 7, and its association with adherence and biofilm formation was investigated. Reverse transcription PCR (RT-PCR showed differential expression in surface-attached biofilm cells than nonadherent cells. In vitro translation showed synthesis of a ∼17 kDa protein, further confirmed by cloning and heterologous expression in E. coli DH5. Up to 2.1-, 3.1-, and 4.1- fold biofilm augmentation was observed on abiotic (polystyrene and biotic (S. cerevisiae/HeLa surface, respectively. Scanning electron microscopy (SEM and gfp-tagged fluorescence microscopy revealed increased adherence to abiotic (glass and biotic (S. cerevisiae surface. Extracellular DNA(eDNA was found significantly during active growth; due to probable involvement of the protein in DNA export, strong sequence homology with MFS transporter proteins, and presence of transmembrane helices. In summary, our findings show that the putative MFS transporter-like ORF (pmt is associated with adherence, biofilm formation, and probable eDNA release in A. baumannii AIIMS 7.
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Thermochemistry of certain rare earth and ammonium double chlorides
International Nuclear Information System (INIS)
Usubaliev, D.U.; Abramtsev, V.A.; Kydynov, M.K.; Vilyaev, A.N.
1987-01-01
In a calorimeter with isothermal casing at 25 deg C dissolution enthalpies of double chlorides of rare earths and ammonium LnCl 3 x2NH 4 Cl (Ln=La, Sm) and LnCl 3 x3NH 4 Cl (Ln=Gd, Tb, Ho) in water, as well as dissolution enthalpy of rare earth chlorides in solution of ammonium chloride and NH 4 Cl in solution of rare earth chloride, have been measured. Formation enthalpies, standard formation enthalpies, dissociation enthalpies of the above-mentioned double chlorides are calculated
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Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions.
Rushdi, Ahmed I; Simoneit, Bernd R T
2005-12-01
Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.
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Ammonium hydrosulfide and clouds in the atmospheres of the giant planets.
Ibragimov, K. Yu.; Solodovnik, A. A.
The physicochemical properties of two possible compounds - ammonium hydrosulfide (NH4SH) and ammonium sulfide (NH4)2S - that may be formed in a reaction of ammonia NH3 with hydrogen sulfide H2S are discussed, and the probability of their formation is analyzed on the basis of the Le Chatelier principle. It is shown that the conditions of their formation on the basis of available data on the concentration ratio of the reagents (NH3 and H2S) in the atmospheres of giant planets make the appearance of enough NH4SH for cloud formation highly problematic. Accordingly, the authors propose as an alternative candidate for a cloud-forming role ammonium sulfide (NH4)2S, for whose formation the conditions in the atmospheres of the giant planets are more favorable. The possible spatial localization of (NH4)2S clouds is estimated, and the result is used in an attempt to identify this compound as one of the chromophores.
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Ammonium detection by formation of colored zebra-bands in a detecting tube.
Hori, Tatsuaki; Niki, Keizou; Kiso, Yoshiaki; Oguchi, Tatsuo; Kamimoto, Yuki; Yamada, Toshiro; Nagai, Masahiro
2010-06-15
Ammonium ion was colorized by means of a diazo coupling reaction with 2-phenylphenol, where the color development reaction was conducted within 3min by using boric acid as a catalyst. The resulting colored solution (0.5ml) was supplied by suction to a detecting tube consisting of a nonwoven fabric test strip (2mm wide, 1mm thick, 150mm long) impregnated with benzylcetyldimethylammonium chloride in a stripe pattern and enclosed in a heat-shrinkable tube. When the colored solution was supplied to the detecting tube, blue zebra-bands formed, and the ammonium concentration was determined by counting the number of zebra-bands. The detection range was 1-20mg-Nl(-1). Ammonium ion in actual domestic wastewater samples was successfully detected by means of this method.
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Thermal decomposition of ammonium uranate; X-ray study
International Nuclear Information System (INIS)
El-Fekey, S.A.; Rofail, N.H.; Khilla, M.A.
1984-01-01
Ammonium uranate was precipitated from a nuclear-pure uranyl nitrate solution using gaseous ammonia. Thermal decomposition of the obtained uranate, at different calcining temperatures, resulted in the formation of amorphous (A-)UO 3 , β-UO 3 , UOsub(2.9), U 3 O 8 (H) and U 3 O 8 (O). The influence of ammonia content, occluded nitrate ions and rate of heating, on the formation of these phases, was studied using X-ray powder diffraction analysis. The results indicated that ammonium uranate UO 2 (OH)sub(2-x)(ONH 4 )x . YH 2 O is a continuous non-stoichiometric system is a continuous non-stoichiometric system with no intermediate stoichiometric compounds and its composition varies according to mode of preparation. The results indicated also that the rate of heating and formation of hydrates are important factors for both UOsub(2.9) and U 3 O 8 (O) formation. (orig.)
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The creation of defects in ammonium halides by excitons
International Nuclear Information System (INIS)
Kim, L.M.
2002-01-01
The ammonium halides crystals and alkali halides crystals are analogous by kind chemical bonds and crystalline lattices. The anionic sublattice is identical in this crystals. It is known the main mechanism of defect creation by irradiation is radiationless decay of excitons in alkali halides crystals. The F-, H-centers are formation in this processes. However, F, H-centres are not detected in ammonium halides. The goal of this work is investigation the creation of defects in ammonium halides by excitons. We established that excitons in ammonium chlorides and bromides are similar to excitons in alkali halides. It is known excitons are self-trapped and have identical parameters of the exciton-phonon interaction in both kind crystals. It is supposed, that processes of radiationless disintegration of excitons are identical in ammonium and alkali halides. It is necessary to understand why F-, H-centers are absent in ammonium halides. V k -centres are created by the excitation of the ammonium halides crystals in the absorption band of excitons. It was established by thermoluminescence and spectrums of absorption. The V k -centers begin to migrate at 110-120 K in ammonium chlorides and bromides. The curve of thermoluminescence have peak with maximum at this temperatures. It is known V k -centers in ammonium chlorides have the absorption band at 380 nm. We discovered this absorption band after irradiation of crystals by ultra-violet. In alkali halides F-center is anionic vacancy with electron. The wave function of electron are spread ed at the cations around anionic vacancy. We established the cation NH 4 + in ammonium halides can to capture electron. The ion NH 4 2+ is unsteady. It is disintegrated to NH 3 + and H + . We suppose that excitons in ammonium and alkali halides are disintegrated identically. When cation NH 4 + capture electron, in the anionic sublattice the configuration are created in a direction (100) The indicated configuration is unsteady in relation to a
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Ambient and laboratory observations of organic ammonium salts in PM1.
Schlag, P; Rubach, F; Mentel, T F; Reimer, D; Canonaco, F; Henzing, J S; Moerman, M; Otjes, R; Prévôt, A S H; Rohrer, F; Rosati, B; Tillmann, R; Weingartner, E; Kiendler-Scharr, A
2017-08-24
Ambient measurements of PM 1 aerosol chemical composition at Cabauw, the Netherlands, implicate higher ammonium concentrations than explained by the formation of inorganic ammonium salts. This additional particulate ammonium is called excess ammonium (e NH 4 ). Height profiles over the Cabauw Experimental Site for Atmospheric Research (CESAR) tower, of combined ground based and airborne aerosol mass spectrometric (AMS) measurements on a Zeppelin airship show higher concentrations of e NH 4 at higher altitudes compared to the ground. Through flights across the Netherlands, the Zeppelin based measurements furthermore substantiate e NH 4 as a regional phenomenon in the planetary boundary layer. The excess ammonium correlates with mass spectral signatures of (di-)carboxylic acids, making a heterogeneous acid-base reaction the likely process of NH 3 uptake. We show that this excess ammonium was neutralized by the organic fraction forming particulate organic ammonium salts. We discuss the significance of such organic ammonium salts for atmospheric aerosols and suggest that NH 3 emission control will have benefits for particulate matter control beyond the reduction of inorganic ammonium salts.
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Lang, Anthony J; Vyazovkin, Sergey
2008-09-11
Dissolving of ammonium nitrate in highly polar polymers such as poly(vinylpyrrolidone) and/or poly(acrylamide) can result in the formation of single-phase glassy solid materials, in which NH 4 (+) and NO 3 (-) are separated through an ion-dipole interaction with the polymer matrix. Below the glass transition temperature of the polymer matrix the resulting materials remain phase and thermally stable as demonstrated through the absence of decomposition as well as the solid-solid transitions and melting of ammonium nitrate. The structure of the materials is explored by Fourier transform infrared spectroscopy and density functional calculations. Differential scanning calorimetry, thermogravimetry, and isoconversional kinetic analysis are applied to characterize the thermal behavior of the materials.
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Pérez Ibarreche, Mariana; Castellano, Patricia; Vignolo, Graciela
2014-01-01
The ability of meat borne anti-Listeria Lactobacillus to form biofilms under different in vitro conditions and on abiotic surfaces was investigated. Biofilm formation by the adhesion to polystyrene microtiter plates was determined, this being higher for Lactobacillus curvatus CRL1532 and CRL705 and Lactobacillus sakei CRL1862. The physicochemical properties of the cell surface were relatively hydrophilic and acidic in character; L. sakei CRL1862 exhibiting the strongest autoaggregation. The adhesion of lactobacilli to stainless steel (SS) and polytetrafluoroethylene (PTFE) supports at 10°C was found to be maximal for L. sakei CRL1862 on SS after 6 days. When biofilm architecture was characterized by epifluorescence and SEM, L. sakei CRL1862 homogeneously covered the SS surface while cell clusters were observed on PTFE; the extracellular polymeric substance matrix adapted to the topography and hydrophilic/hydrophobic characteristics of each material. The feasibility of L. sakei CRL1862 to form biofilm on materials used in meat processing highlights its potential as a control strategy for Listeria monocytogenes biofilms. © 2013. Published by Elsevier Ltd. All rights reserved.
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The Stable Isotope Fractionation of Abiotic Reactions: A Benchmark in the Detection of Life
Summers, David P.
2003-01-01
One very important tool in the analysis of biogenic, and potentially biogenic, samples is the study of their stable isotope distributions. The isotope distribution of a sample depends on the process(es) that created it. One important application of the analysis of C & N stable isotope ratios has been in the determination of whether organic matter in a sample is of biological origin or was produced abiotically. For example, the delta C-13 of organic material found embedded in phosphate grains was cited as a critical part of the evidence for life in 3.8 billion year old samples. The importance of such analysis in establishing biogenicity was highlighted again by the role this issue played in the recent debate over the validity of what had been accepted as the Earth s earliest microfossils. These kinds of analysis imply a comparison with the fractionation that one would have seen if the organic material had been produced by alternative, abiotic, pathways. Could abiotic reactions account for the same level of fractionation? Additionally, since the fractionation can vary between different abiotic reactions, understanding their fractionations can be important in distinguishing what reactions may have been significant in the formation of different abiological samples (such as extraterrestrial samples). There is however, a scarcity of data on the fractionation of carbon and nitrogen by abiotic reactions. In order to interpret properly what the stable isotope ratios of samples tell us about their biotic or abiotic nature, more needs to be known about how abiotic reactions fractionate C and N. Carbon isotope fractionations have been studied for a few abiotic processes. These studies presumed the presence of a reducing atmosphere, focusing on reactions involving spark discharge, W photolysis of reducing gas mixtures, and cyanide polymerization in the presence of ammonia. They did find that the initial products showed a depletion in I3C with values in the range of a few per
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Pathways for abiotic organic synthesis at submarine hydrothermal fields.
McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P
2015-06-23
Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.
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Role of ambient ammonia in particulate ammonium formation at a rural site in the North China Plain
Meng, Zhaoyang; Xu, Xiaobin; Lin, Weili; Ge, Baozhu; Xie, Yulin; Song, Bo; Jia, Shihui; Zhang, Rui; Peng, Wei; Wang, Ying; Cheng, Hongbing; Yang, Wen; Zhao, Huarong
2018-01-01
The real-time measurements of NH3 and trace gases were conducted, in conjunction with semi-continuous measurements of water-soluble ions in PM2.5 at a rural site in the North China Plain (NCP) from May to September 2013 in order to better understand chemical characteristics of ammonia and the impact of secondary ammonium aerosols on formation in the NCP. Extremely high NH3 and NH4+ concentrations were observed after a precipitation event within 7-10 days following urea application. Elevated NH3 levels coincided with elevated NH4+, indicating that NH3 likely influenced particulate ammonium mass. For the sampling period, the average conversion / oxidation ratios for NH4+ (NHR), SO42- (SOR), and NO3- (NOR) were estimated to be 0.30, 0.64, and 0.24, respectively. The increased NH3 concentrations, mainly from agricultural activities and regional transport, coincided with the prevailing meteorological conditions. The high NH3 level with NHR of about 0.30 indicates that the emission of NH3 in the NCP is much higher than needed for aerosol acid neutralisation, and NH3 plays an important role in the formation of secondary aerosols as a key neutraliser. The hourly data obtained were used to investigate gas-aerosol partitioning characteristics using the thermodynamic equilibrium model ISORROPIA-II. Modelled SO42-, NO3-, and NH3 values agree well with the measurements, while the modelled NH4+ values largely underestimate the measurements. Our observation and modelling results indicate that strong acids in aerosol are completely neutralised. Additional NH4+ exists in aerosol, probably a result of the presence of a substantial amount of oxalic and other diacids.
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Energy Technology Data Exchange (ETDEWEB)
Piña, M. Nieves, E-mail: neus.pinya@uib.es; López, Kenia A.; Costa, Antoni; Morey, Jeroni, E-mail: jeroni.morey@uib.es
2013-10-10
Graphical abstract: - Highlights: • The enthalpy–entropy compensation in the complex is independent of the spacer used. • The enthalpy–entropy compensation is dependent on the microscopic nature of the binary mixture. • The enthalpy–entropy compensation is dependent on the proportion of the components of the binary mixture. - Abstract: An isothermal titration microcalorimetry (ITC) study on the supramolecular complex formation between carboxylates and ammonium-squaramido based receptors at different ethanol:water proportions is reported. The results obtained show that the formation enthalpy sign of a supramolecular complex in a water–ethanol binary mixture can be influenced by the proportion of the cosolvent. Moreover there is an enthalpy–entropy compensation process in the supramolecular complex formation; in poor water mixtures the process is endothermic, whilst in reach water mixtures the process is exothermic. This behavior is mostly due to the intrinsic nature of the mixture between water and ethanol, and particularly the process of solvation and desolvation of receptor, substrate and complex. When this study is repeated with binary mixtures of water–methanol and water–DMSO it is observed that the nature of the organic solvent affects the results. While the mixture water–methanol has a behavior similar to water–ethanol mixture, the water–DMSO mixture shows clear differences. In order to check this compensation process, △Cp values are calculated at two different proportions water–ethanol, and they are consistent with an enthalpy–entropy compensation process similar to that described by the inclusion process for certain hydrophilic cyclodextrines. The results obtained show that the enthalpy–entropy compensation detected in the supramolecular complex formation between carboxylates and ammonium-squaramido receptors is independent of the spacer used, and more dependent on the microscopic nature and proportion of the binary mixture.
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International Nuclear Information System (INIS)
Piña, M. Nieves; López, Kenia A.; Costa, Antoni; Morey, Jeroni
2013-01-01
Graphical abstract: - Highlights: • The enthalpy–entropy compensation in the complex is independent of the spacer used. • The enthalpy–entropy compensation is dependent on the microscopic nature of the binary mixture. • The enthalpy–entropy compensation is dependent on the proportion of the components of the binary mixture. - Abstract: An isothermal titration microcalorimetry (ITC) study on the supramolecular complex formation between carboxylates and ammonium-squaramido based receptors at different ethanol:water proportions is reported. The results obtained show that the formation enthalpy sign of a supramolecular complex in a water–ethanol binary mixture can be influenced by the proportion of the cosolvent. Moreover there is an enthalpy–entropy compensation process in the supramolecular complex formation; in poor water mixtures the process is endothermic, whilst in reach water mixtures the process is exothermic. This behavior is mostly due to the intrinsic nature of the mixture between water and ethanol, and particularly the process of solvation and desolvation of receptor, substrate and complex. When this study is repeated with binary mixtures of water–methanol and water–DMSO it is observed that the nature of the organic solvent affects the results. While the mixture water–methanol has a behavior similar to water–ethanol mixture, the water–DMSO mixture shows clear differences. In order to check this compensation process, △Cp values are calculated at two different proportions water–ethanol, and they are consistent with an enthalpy–entropy compensation process similar to that described by the inclusion process for certain hydrophilic cyclodextrines. The results obtained show that the enthalpy–entropy compensation detected in the supramolecular complex formation between carboxylates and ammonium-squaramido receptors is independent of the spacer used, and more dependent on the microscopic nature and proportion of the binary mixture
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Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids
International Nuclear Information System (INIS)
Garaev, Valeriy; Pavlovica, Sanita; Vaivars, Guntars; Kleperis, Janis
2012-01-01
In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.
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DEFF Research Database (Denmark)
Arturi, Katarzyna R.; Bender Koch, Christian; Søgaard, Erik G.
2017-01-01
Removal of iron is an important step in groundwater treatment for drinking water production. It is performed to prevent organoleptic issues and clogging in water supply systems. Iron can be eliminated with a purely physico-chemical (abiotic) method or biotically with the help of iron......-oxidizing bacteria (FeOB). Each of the purification methods requires different operating conditions and results in formation of iron oxyhydroxide (FeOOH) precipitates. Knowledge about the differences in composition and properties of the biotic and abiotic precipitates is desirable from a technical, but also...
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DEFF Research Database (Denmark)
Broholm, Mette Martina; Hunkeler, Daniel; Tuxen, Nina
2014-01-01
not appear to be reductive dechlorination via 1,1-DCA. In the biotic microcosms, the degradation of 1,1,1-TCA occurred under iron and sulfate reducing conditions. Biotic reduction of iron and sulfate likely resulted in formation of FeS, which can abiotically degrade 1,1,1-TCA. Hence, abiotic degradation of 1...
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Treating ammonium-rich wastewater with sludge from water treatment plant to produce ammonium alum
Directory of Open Access Journals (Sweden)
Wen-Po Cheng
2016-03-01
Full Text Available This study applies a process to treat ammonium-rich wastewater using alum-generated sludge form water purification plant, and gain economic benefit by producing ammonium alum (Al(NH4(SO42·12H2O. The factors affecting production of ammonium alum include molar ratio of ammonium to aluminum concentration, sulfuric acid concentration, mixing speed, mixing time, standing time, and temperature. According to the equation for the ammonium removal reaction, the theoretical quantity of ammonium alum was calculated based on initial and final concentrations of ammonium. Then, the weight of ammonium alum crystal was divided by the theoretical weight to derive the recovery ratio. The optimum sludge and sulfuric acid dosage to treat about 17 g L−1 ammonium wastewater are 300 g L−1 and 100 mL L−1, respectively. The optimal dosage for wastewater is molar ratio of ammonium to aluminum of about 1 due to the aluminum dissolving in acidified wastewater. The ammonium removal efficiency is roughly 70% and the maximum recovery ratio for ammonium alum is 93% when the wastewater is mixed for 10 min at the mixing velocity gradient of 100 s−1. Ammonium alum production or ammonium removal can be enhanced by controlling the reaction at low temperatures.
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Ammonium Nitrogen Removal from Urea Fertilizer Plant Wastewater via Struvite Crystal Production
Machdar, I.; Depari, S. D.; Ulfa, R.; Muhammad, S.; Hisbullah, A. B.; Safrul, W.
2018-05-01
Elimination of ammonium concentration from urea fertilizer plant wastewater through struvite crystal (NH4MgPO4.6H2O) formation by adding MgCl2, KH2PO4, and KOH were studied. This method of elimination has two benefits, namely, reducing ammonium nitrogen content in the wastewater, as well as production of a valuable material (struvite crystal). Struvite is known as a slow-release fertilizer and less soluble. This report presents the ammonium removal efficiencies during struvite formation. The growth of struvite production under different molar ratios of Mg2+:NH4 +:PO4 3- and solution pH is also discussed. To find the efficiencies and measure the growth rates, lab-scale experiments were conducted in a batch crystallizer-reactor. SEM, XRD, and FTIR observation were also applied to investigate the characteristics of struvite. The reactant molar ratios of Mg2+:NH4 +:PO4 3- of 1.2:1:1, 1:1:1.2, and 1:1:1 were evaluated. Each of the molar ratios was treated at the solution pH of 8, 9, and 10. It was found that, the highest ammonium removal efficiency was 94.7% at the molar ratio of 1.2:1:1 and pH of 9. Primarily, the growth rate of struvite formation complied with a first-order kinetic model. The rate constants (k1) were calculated to be 2.6, 4.3, and 5.0 h-1 for solution pH of 8, 9, and 10, respectively. The findings of the study provide suggestion for an alternative sustainable recovery of ammonium nitrogen content in a urea fertilizer plant effluent.
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Ahn, Il-Pyung
2008-01-01
Glufosinate ammonium diminished developments of rice (Oryza sativa) blast and brown leaf spot in 35S:bar-transgenic rice. Pre- and postinoculation treatments of this herbicide reduced disease development. Glufosinate ammonium specifically impeded appressorium formation of the pathogens Magnaporthe grisea and Cochliobolus miyabeanus on hydrophobic surface and on transgenic rice. In contrast, conidial germination remained unaffected. Glufosinate ammonium diminished mycelial growth of two pathogens; however, this inhibitory effect was attenuated in malnutrition conditions. Glufosinate ammonium caused slight chlorosis and diminished chlorophyll content; however, these alterations were almost completely restored in transgenic rice within 7 d. Glufosinate ammonium triggered transcriptions of PATHOGENESIS-RELATED (PR) genes and hydrogen peroxide accumulation in transgenic rice and PR1 transcription in Arabidopsis (Arabidopsis thaliana) wild-type ecotype Columbia harboring 35S:bar construct. All transgenic Arabidopsis showed robust hydrogen peroxide accumulation by glufosinate ammonium. This herbicide also induced PR1 transcription in etr1 and jar1 expressing bar; however, no expression was observed in NahG and npr1. Fungal infection did not alter transcriptions of PR genes and hydrogen peroxide accumulation induced by glufosinate ammonium. Infiltration of glufosinate ammonium did not affect appressorium formation of M. grisea in vivo but inhibited blast disease development. Hydrogen peroxide scavengers nullified blast protection and transcriptions of PR genes by glufosinate ammonium; however, they did not affect brown leaf spot progression. In sum, both direct inhibition of pathogen infection and activation of defense systems were responsible for disease protection in bar-transgenic rice.
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International Nuclear Information System (INIS)
Karelin, A.I.; Lobas, O.P.; Zhiganov, A.N.; Vasil'ev, K.F.; Zhiganova, A.A.
1988-01-01
The influence of ammonium nitrate on the mechanism and kinetics of dehydration and thermal decomposition of ammonium polyuranates was studied. An appreciable influence of the nitrate ion content in the samples of ammonium polyuranates on the development of thermal stability has been noted. The kinetic parameters of the thermal decomposition of ammonium polyuranates have been evaluated. A mechanism of the dehydration and thermal decomposition of ammonium polyuranates in the presence of ammonium nitrate has been proposed. It was shown that increase in the content of ammonium nitrate in the precipitate of ammonium polyuranates leads to a decrease in the specific surface of uranoso-uranic oxide
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Liu, Shurong; Berns, Anne E.; Vereecken, Harry; Wu, Di; Brüggemann, Nicolas
2017-02-01
Abiotic conversion of the reactive nitrification intermediate hydroxylamine (NH2OH) to nitrous oxide (N2O) is a possible mechanism of N2O formation during nitrification. Previous research has demonstrated that manganese dioxide (MnO2) and organic matter (OM) content of soil as well as soil pH are important control variables of N2O formation in the soil. But until now, their combined effect on abiotic N2O formation from NH2OH has not been quantified. Here, we present results from a full-factorial experiment with artificial soil mixtures at five different levels of pH, MnO2 and OM, respectively, and quantified the interactive effects of the three variables on the NH2OH-to-N2O conversion ratio (RNH2OH-to-N2O). Furthermore, the effect of OM quality on RNH2OH-to-N2O was determined by the addition of four different organic materials with different C/N ratios to the artificial soil mixtures. The experiments revealed a strong interactive effect of soil pH, MnO2 and OM on RNH2OH-to-N2O. In general, increasing MnO2 and decreasing pH increased RNH2OH-to-N2O, while increasing OM content was associated with a decrease in RNH2OH-to-N2O. Organic matter quality also affected RNH2OH-to-N2O. However, this effect was not a function of C/N ratio, but was rather related to differences in the dominating functional groups between the different organic materials.
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International Nuclear Information System (INIS)
Fedorov, P.I.; Andreev, V.K.; Slotvinskij-Sidak, N.P.
1978-01-01
Solubility at 25 deg C has been studied in the system ammonium metavanadate - sodium bicarbonate - water which is a stable section of the corresponding quaternary mutual system. In the eutonic point the content of ammonium metavanadate is 4.95% and of sodium bicarbonate 12.1%. The crystallization branch of ammonium metavanadate has been studied in the system ammonium metavanadate - ammonium carbonate - water at 25 deg C. Metavanadate solubility attains minimum (0.14%) at ammonium carbonate concentration 2.6%. Three sections have been studied of the quaternary system ammonium - metavanadate - ammonium carbonate - sodium bicarbonate-water at 25 deg C in the crystallization region of ammonium metavanadate at a ratio of sodium bicarbonate to ammonium carbonate 3:1, 1:1, and 1:3. A region of minimum solubility of ammonium metavanadate has been detected (0.1%)
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DEFF Research Database (Denmark)
Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna
2012-01-01
was not enhanced. The ammonium-induced stimulation of EAAT3 increased with increasing extracellular pH, suggesting that the gaseous form NH(3) mediates the effect. An ammonium-induced intracellular alkalinization was excluded as the cause of the enhanced EAAT3 activity because 1) ammonium acidified the oocyte...
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DEFF Research Database (Denmark)
Schramm, Andreas; Revsbech, Niels Peter; Dalsgaard, Tage
2006-01-01
ACTIVITY, MICROENVIRONMENTS, AND COMMUNITY STRUCTURE OF AEROBIC AND ANAEROBIC AMMONIUM OXIDIZING PROKARYOTES IN ESTUARINE SEDIMENT (RANDERS FJORD, DK) A. Schramm 1, N.P. Revsbech 1, T. Dalsgaard 2, E. Piña-Ochoa 3, J. de la Torré 4, D.A. Stahl 4, N. Risgaard-Petersen 2 1 Department of Biological...... conversion of ammonium with nitrite to N2, is increasingly recognized as link in the aquatic nitrogen cycle. However, factors regulating the occurrence and activity of anammox bacteria are still poorly understood. Besides the influence of abiotic factors, anammox might be controlled by either aerobic ammonia...... oxidizing bacteria and archaea (AOB and AOA) or nitrate-reducing/denitrifying bacteria via their supply of nitrite. Along the Randers Fjord estuary (Denmark), gradients of salinity, nutrients, and organic loading can be observed, and anammox has been detected previously at some sites. The aim of this study...
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International Nuclear Information System (INIS)
Karelin, A.I.; Lobas, O.P.; Zhiganov, A.N.; Vasil'ev, K.F.; Zhiganova, A.A.
1987-01-01
A study was made on ammonium nitrate effect on the mechanism and kinetics of dehydration and thermal decomposition of ammonium polyuranates. Sufficient effect of nitrate ion content in ammonium polyuranate samples on their thermal stability was noted. Kinetic parameters of thermal decomposition of ammonium polyuranates were evaluated. Mechanism of dehydration and thermal decomposition of ammonium polyuranates in the presence of ammonium nitrate was suggested. It was shown that increase of ammonium nitrate content in ammonium polyuranate precipitate resulted to reduction of the specific surface of prepared uranium mixed oxide
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Rocket Solid Propellant Alternative Based on Ammonium Dinitramide
Directory of Open Access Journals (Sweden)
Grigore CICAN
2017-03-01
Full Text Available Due to the continuous run for a green environment the current article proposes a new type of solid propellant based on the fairly new synthesized oxidizer, ammonium dinitramide (ADN. Apart of having a higher specific impulse than the worldwide renowned oxidizer, ammonium perchlorate, ADN has the advantage, of leaving behind only nitrogen, oxygen and water after decomposing at high temperatures and therefore totally avoiding the formation of hydrogen chloride fumes. Based on the oxidizer to fuel ratios of the current formulations of the major rocket solid booster (e.g. Space Shuttle’s SRB, Ariane 5’s SRB which comprises mass variations of ammonium perchlorate oxidizer (70-75%, atomized aluminum powder (10-18% and polybutadiene binder (12-20% a new solid propellant was formulated. As previously stated, the new propellant formula and its variations use ADN as oxidizer and erythritol tetranitrate as fuel, keeping the same polybutadiene as binder.
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Energy Technology Data Exchange (ETDEWEB)
Tratnyek, Paul G. [Oregon Health & Science Univ., Beaverton, OR (United States); Tebo, Bradley M. [Oregon Health & Science Univ., Beaverton, OR (United States); Fan, Dimin [Oregon Health & Science Univ., Beaverton, OR (United States); Anitori, Roberto [Oregon Health & Science Univ., Beaverton, OR (United States); Szecsody, Jim [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jansik, Danielle [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2015-11-14
rapid in the presence of sulfide and nZVI, although the rate was suppressed at the higher S/Fe ratios tested. This suppression appeared to be due to the formation of Tc-containing colloids. As with the biotic experiments, pertechnetate reduced under sulfidic conditions was highly resistant to reoxidation. The microscopic morphology of abiotically-transformed nZVI particles varied significantly with those in the biotic experiment, although mackinawite was formed in both systems (as indicated by μXRD and Mössbauer spectroscopy). Preliminary XAS analysis pointed to a mixture of Tc-O and Tc-S binding in the abiotic sulfide/nZVI system, while the major reduced solids under non-sulfidic conditions were TcO2•nH2O. The presence of sediment and advective flow to the TcO4-/nZVI/sulfide system results in additional processes occurring. Although the natural Hanford sediment used has sufficient available ferrous iron to slowly reduce TcO4-, under anaerobic conditions, that rate is orders of magnitude slower than reduction by nZVI/sulfide. Batch and 1-D column experiments showed that the TcO4- reduction rate increased with the sediment surface area (with the same nZVI mass). As in batch systems, column studies showed that the presence of sulfide with TcO4- at low (2-5 mM) concentrations increased the TcO4- reduction rate and high (10-30 mM) sulfide decreased the rate. This change is attributed to the formation of sulfide precipitates on the nZVI and sediment surfaces. Injection of low and high sulfide (i.e. pretreatment) prior to TcO4-/sulfide injection also greatly decreased the TcO4- reduction rate, likely decreasing the generation of ferrous iron from the nZVI. Although the high sulfide systems have slower Tc reduction rates, 190 times more Tc mass precipitated than in the low sulfide systems and the
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Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine
Huang, Rui; Furukawa, Yoshihiro; Otake, Tsubasa; Kakegawa, Takeshi
2017-06-01
The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively. In this study, we investigated the effects of water, ammonia, ammonium bicarbonate, pH, and glycine on the oligomerization and degradation of methionine under high pressure (150 MPa) and high temperature conditions (175 °C) for 96 h. Methionine is more difficult to oligomerize than glycine and methionine dimer was formed in the incubation of dry powder of methionine. Methionine oligomers as long as trimers, as well as methionylglycine and glycylmethionine, were formed under every condition with these additional compounds. Among the compounds tested, the oligomerization reaction rate was accelerated by the presence of water and by an increase in pH. Ammonia also increased the oligomerization rate but consumed methionine by side reactions and resulted in the rapid degradation of methionine and its peptides. Similarly, glycine accelerated the oligomerization rate of methionine and the degradation of methionine, producing water, ammonia, and bicarbonate through its decomposition. With Gly, heterogeneous dimers (methionylglycine and glycylmethionine) were formed in greater amounts than with other additional compounds although smaller amount of these heterogeneous dimers were formed with other additional compounds. These results suggest that accelerated reaction rates induced by water and co-existing reactive compounds promote the oligomerization
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Formation of low charge state ions of synthetic polymers using quaternary ammonium compounds.
Nasioudis, Andreas; Joyce, William F; van Velde, Jan W; Heeren, Ron M A; van den Brink, Oscar F
2010-07-01
Factors such as high polymer dispersity and variation in elemental composition (of copolymers) often complicate the electrospray ionization mass spectrometry (ESI-MS) analysis of synthetic polymers with high molar mass. In the experiments described in this study, quaternary ammonium compounds were observed to facilitate the production of low charge state pseudomolecular ions when added to the spray solution for ESI-MS. This approach was then used for the ESI time-of-flight mass spectrometry (TOF-MS) analysis of synthetic polymers. Hexadecyltrimethylammonium chloride permitted the successful analysis of poly(ethylene glycol) of 2-40 kDa, poly(propylene glycol) and poly(tetramethylene glycol) oligomers. Increasing the quaternary ammonium compounds' concentration results in the production of low charge state pseudomolecular ions. A comparison of structurally different quaternary ammonium compounds showed that the best performance is expected from large molecules with specific charge localization, which leaves the charge available for interactions. The applicability of the method for the MS analysis of other polymeric systems was also studied. In the case of poly(tetramethylene glycol), the method not only shifted the distributions to higher m/z values but also allowed the detection of high molecular weight material that was not observed without addition of the modifier to the spray solution.
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Ammonium nitrate explosion hazards
Directory of Open Access Journals (Sweden)
Negovanović Milanka
2015-01-01
Full Text Available Ammonium nitrate (AN primarily is used as a fertilizer but it is also very important compound in the production of industrial explosives. The application of ammonium nitrate in the production of industrial explosives was related with the early era of Nobel dynamite and widely increased with the appearance of blasting agents such as ANFO and Slurry, in the middle of the last Century. Throughout the world millions of tons of ammonium nitrate are produced annually and handled without incident. Although ammonium nitrate generally is used safely, accidental explosions involving AN have high impact resulting in loss of lives and destruction of property. The paper presents the basic properties of ammonium nitrate as well as hazards in handling of ammonium nitrate in order to prevent accidents. Several accidents with explosions of ammonium nitrate resulted in catastrophic consequences are listed in the paper as examples of non-compliance with prescribed procedures.
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Sulfation of corrosive alkali chlorides by ammonium sulfate in a biomass fired CFB boiler
Energy Technology Data Exchange (ETDEWEB)
Brostroem, Markus; Backman, Rainer; Nordin, Anders [Energy Technology and Thermal Process Chemistry, Umeaa University, SE-901 87 Umeaa (Sweden); Kassman, Haakan [Vattenfall Power Consultant AB, Box 1046, SE-611 29 Nykoeping (Sweden); Helgesson, Anna; Berg, Magnus; Andersson, Christer [Vattenfall Research and Development AB, SE-814 26 Aelvkarleby (Sweden)
2007-12-15
Biomass and waste derived fuels contain relatively high amounts of alkali and chlorine, but contain very little sulfur. Combustion of such fuels can result in increased deposit formation and superheater corrosion. These problems can be reduced by using a sulfur containing additive, such as ammonium sulfate, which reacts with the alkali chlorides and forms less corrosive sulfates. Ammonium sulfate injection together with a so-called in situ alkali chloride monitor (IACM) is patented and known as ''ChlorOut''. IACM measures the concentrations of alkali chlorides (mainly KCl in biomass combustion) at superheater temperatures. Tests with and without spraying ammonium sulfate into the flue gases have been performed in a 96MW{sub th}/25MW{sub e} circulating fluidized bed (CFB) boiler. The boiler was fired mainly with bark and a chlorine containing waste. KCl concentration was reduced from more than 15 ppm to approximately 2 ppm during injection of ammonium sulfate. Corrosion probe measurements indicated that both deposit formation and material loss due to corrosion were decreased using the additive. Analysis of the deposits showed significantly higher concentration of sulfur and almost no chlorine in the case with ammonium sulfate. Results from impactor measurements supported that KCl was sulfated to potassium sulfate by the additive. (author)
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池田, 元輝; 渡辺, 孝賢; Ikeda, Motoki; Watanabe, Takayasu
2002-01-01
A pot experiment was conducted to evaluate the efficiency of ammonium- and nitrate- nitrogen contained in irrigation water during the reproductive growth period of paddy rice （Oryza sativa L. cv. Hinohikari） that did not receive topdressed nitrogen at the panicle formation stage. lrrigation of water containing a low level of nitrogen （7mgNL^-1） did not increase yields so much compared to topdressed nitrogen. lrrigation of water containing a high level of nitrogen （14mgNL^-1） caused substantia...
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Crystallization characteristics of ammonium uranyl carbonate (AUC) in ammonium carbonate solutions
International Nuclear Information System (INIS)
Kim, T.J.; Jeong, K.C.; Park, J.H.; Chang, I.S.; Choi, C.S.
1994-01-01
Ammonium carbonate solutions with an excessive amount of NH 3 were produced in a commercial AUC (ammonium uranyl carbonate) conversion plant. In this study the AUC crystals, precipitated with uranyl nitrate and ammonium carbonate solutions prepared in the laboratory, were characterized to determine the feasibility of recycling ammonium carbonate solution. The AUC crystals were easily agglomerated with the increasing concentration of CO 3 2- and mole ratio of NH 4 + /CO 3 2- in ammonium carbonate solution. Effects of a mixing system for the solution in the AUC crystallizer and the feed location of the solution onthe agglomeration of AUC crystals were also studied along with the effects of agglomerated AUC powders on UO 2 powders. Finally, the feasibility of manufacturing UO 2 fuel with a sintered pellet density of 10.52 g/cm 3 , using the AUC powders generated in this experiment, was demonstrated. (orig.)
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Sun, Zhongfeng; Song, Jiabin; Xin, Xi'an; Xie, Xianan; Zhao, Bin
2018-01-01
Arbuscular mycorrhizal (AM) fungi are soil-borne fungi belonging to the ancient phylum Glomeromycota and are important symbionts of the arbuscular mycorrhiza, enhancing plant nutrient acquisition and resistance to various abiotic stresses. In contrast to their significant physiological implications, the molecular basis involved is poorly understood, largely due to their obligate biotrophism and complicated genetics. Here, we identify and characterize three genes termed Fm201 , Ri14-3-3 and RiBMH2 that encode 14-3-3-like proteins in the AM fungi Funneliformis mosseae and Rhizophagus irregularis , respectively. The transcriptional levels of Fm201 , Ri14-3-3 and RiBMH2 are strongly induced in the pre-symbiotic and symbiotic phases, including germinating spores, intraradical hyphae- and arbuscules-enriched roots. To functionally characterize the Fm201 , Ri14-3-3 and RiBMH2 genes, we took advantage of a yeast heterologous system owing to the lack of AM fungal transformation systems. Our data suggest that all three genes can restore the lethal Saccharomyces cerevisiae bmh1 bmh2 double mutant on galactose-containing media. Importantly, yeast one-hybrid analysis suggests that the transcription factor RiMsn2 is able to recognize the STRE (CCCCT/AGGGG) element present in the promoter region of Fm201 gene. More importantly, Host-Induced Gene Silencing of both Ri14-3-3 and RiBMH2 in Rhizophagus irregularis impairs the arbuscule formation in AM symbiosis and inhibits the expression of symbiotic PT4 and MST2 genes from plant and fungal partners, respectively. We further subjected the AM fungus- Medicago truncatula association system to drought or salinity stress. Accordingly, the expression profiles in both mycorrhizal roots and extraradical hyphae reveal that these three 14-3-3-like genes are involved in response to drought or salinity stress. Collectively, our results provide new insights into molecular functions of the AM fungal 14-3-3 proteins in abiotic stress responses and
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Energy Technology Data Exchange (ETDEWEB)
Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Box 1410, 50-950 Wrocław 2 (Poland); Gągor, Anna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Box 1410, 50-950 Wrocław 2 (Poland); Hanuza, Jerzy [Department of Bioorganic Chemistry, University of Economics, 53 345 Wroclaw (Poland); Pikul, Adam; Drozd, Marek [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Box 1410, 50-950 Wrocław 2 (Poland)
2017-01-15
Two novel formate frameworks templated by ammonium and diethylammonium (DEtA{sup +}) cations have been synthesized. Chemical analysis as well as optical, Raman and IR studies showed partial substitution of nickel ions by Cr(III) or Fe(III). X-ray diffraction revealed that these compounds crystallize in the chiral-type structure of P6{sub 3}22 symmetry. The oxygen atoms from formate ligands form octahedral coordination around the metal centers and the octahedra are bridged by the formate groups in the anti-anti mode configuration forming the hexagonal structure with large channels expanding along the c direction. The channels are filled with disordered DEtA{sup +} and NH{sub 4}{sup +} ions and they show unusual compression with the c/a ratio of only 0.862 and 0.852 for the iron- and chromium-containing compound, respectively. Magnetic studies revealed that the both compounds order magnetically at low temperatures but the ordering temperature is significantly higher for the iron compound (37 K) compared to the chromium analogue (26 K). - Graphical abstract: Temperature dependence of magnetization M of DEtAFeNi showing magnetic order at 37 K. - Highlights: • Two novel chiral formates of P6{sub 3}22 symmetry were synthesized. • The structures contain strongly compressed hexagonal channels filled with disordered cations. • The obtained compounds exhibit magnetic order at low temperatures. • Raman, IR and absorption spectra prove incorporation of Cr(III) and Fe(III) in the frameworks.
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González-Curbelo, Miguel Ángel; Lehotay, Steven J; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel
2014-09-05
The "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to sample preparation is widely applied in pesticide residue analysis, but the use of magnesium sulfate and other nonvolatile compounds for salting out in the method is not ideal for mass spectrometry. In this study, we developed and evaluated three new different versions of the QuEChERS method using more volatile salts (ammonium chloride and ammonium formate and acetate buffers) to induce phase separation and extraction of 43 representative pesticide analytes of different classes. Fast low-pressure gas chromatography tandem mass spectrometry (LPGC-MS/MS) and liquid chromatography (LC)-MS/MS were used for analysis. The QuEChERS AOAC Official Method 2007.01 was also tested for comparison purposes. Of the studied methods, formate buffering using 7.5g of ammonium formate and 15mL of 5% (v/v) formic acid in acetonitrile for the extraction of 15g of sample (5g for wheat grain) provided the best performance and practical considerations. Method validation was carried out with and without the use of dispersive solid-phase extraction for cleanup, and no significant differences were observed for the majority of pesticides. The method was demonstrated in quantitative analysis for GC- and LC-amenable pesticides in 4 representative food matrices (apple, lemon, lettuce, and wheat grain). With the typical exceptions of certain pH-dependent and labile pesticides, 90-110% recoveries and Detection limits were mostly <5ng/g, which met the general need to determine pesticide concentrations as low as 10ng/g for monitoring purposes in food applications. Published by Elsevier B.V.
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Ahn, Il-Pyung
2008-01-01
Glufosinate ammonium diminished developments of rice (Oryza sativa) blast and brown leaf spot in 35S:bar-transgenic rice. Pre- and postinoculation treatments of this herbicide reduced disease development. Glufosinate ammonium specifically impeded appressorium formation of the pathogens Magnaporthe grisea and Cochliobolus miyabeanus on hydrophobic surface and on transgenic rice. In contrast, conidial germination remained unaffected. Glufosinate ammonium diminished mycelial growth of two pathogens; however, this inhibitory effect was attenuated in malnutrition conditions. Glufosinate ammonium caused slight chlorosis and diminished chlorophyll content; however, these alterations were almost completely restored in transgenic rice within 7 d. Glufosinate ammonium triggered transcriptions of PATHOGENESIS-RELATED (PR) genes and hydrogen peroxide accumulation in transgenic rice and PR1 transcription in Arabidopsis (Arabidopsis thaliana) wild-type ecotype Columbia harboring 35S:bar construct. All transgenic Arabidopsis showed robust hydrogen peroxide accumulation by glufosinate ammonium. This herbicide also induced PR1 transcription in etr1 and jar1 expressing bar; however, no expression was observed in NahG and npr1. Fungal infection did not alter transcriptions of PR genes and hydrogen peroxide accumulation induced by glufosinate ammonium. Infiltration of glufosinate ammonium did not affect appressorium formation of M. grisea in vivo but inhibited blast disease development. Hydrogen peroxide scavengers nullified blast protection and transcriptions of PR genes by glufosinate ammonium; however, they did not affect brown leaf spot progression. In sum, both direct inhibition of pathogen infection and activation of defense systems were responsible for disease protection in bar-transgenic rice. PMID:17981989
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Relations of ammonium minerals at several hydrothermal systems in the western U.S.
Krohn, M.D.; Kendall, C.; Evans, J.R.; Fries, T.L.
1993-01-01
Ammonium bound to silicate and sulfate minerals has recently been located at several major hydrothermal systems in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known hydrothermal systems is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH4+ by K+ or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14??? range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these hydrothermal systems, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles. ?? 1993.
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Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.
Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F
2011-05-01
Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011
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Crystallisation of mixtures of ammonium nitrate, ammonium sulphate and soot
Dougle, P.G.; Veefkind, J.P.; Brink, H.M. ten
1998-01-01
Crystallisation of laboratory aerosols of ammonium nitrate and of internal mixtures of this salt with ammonium sulphate were investigated using humidity controlled nephelometry. The aerosol was produced via nebulizing of solutions and then dried to 25% RH, which is a realistic minimum value for
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2010-10-01
... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...
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Abiotic and microbial interactions during anaerobic transformations of Fe(II and NOx-
Directory of Open Access Journals (Sweden)
Flynn ePicardal
2012-03-01
Full Text Available Microbial Fe(II oxidation using NO3- as the terminal electron acceptor (nitrate-dependent Fe(II oxidation; NDFO has been studied for over 15 years. Although there are reports of autotrophic isolates and stable enrichments, many of the bacteria capable of NDFO are known organotrophic NO3- -reducers that require the presence of an organic, primary substrate, e.g., acetate, for significant amounts of Fe(II oxidation. Although the thermodynamics of Fe(II oxidation are favorable when coupled to either NO3- or NO2- reduction, the kinetics of abiotic Fe(II oxidation by NO3- are relatively slow except under special conditions. NDFO is typically studied in batch cultures containing millimolar concentrations of Fe(II, NO3-, and the primary substrate. In such systems, NO2- is often observed to accumulate in culture media during Fe(II oxidation. Compared to NO3-, abiotic reactions of biogenic NO2- and Fe(II are relatively rapid. The kinetics and reaction pathways of Fe(II oxidation by NO2- are strongly affected by medium composition and pH, reactant concentration, and the presence of Fe(II-sorptive surfaces, e.g., Fe(III oxyhydroxides and cellular surfaces. In batch cultures, the combination of abiotic and microbial Fe(II oxidation can alter product distribution and, more importantly, results in the formation of intracellular precipitates and extracellular Fe(III oxyhydroxide encrustations that apparently limit further cell growth and Fe(II oxidation. Unless steps are taken to minimize or account for potential abiotic reactions, results of microbial NDFO studies can be obfuscated by artifacts of the chosen experimental conditions, the use of inappropriate analytical methods, and the resulting uncertainties about the relative importance of abiotic and microbial reactions.In this manuscript, abiotic reactions of NO3- and NO2- with aqueous Fe2+, chelated Fe(II, and solid-phase Fe(II are reviewed along with factors that can influence overall NDFO reac
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Waterproofing Materials for Ammonium Nitrate
R.S. Damse
2004-01-01
This study explores the possibility of overcoming the problem of hygroscopicity of ammonium nitrate by coating the particles with selected waterproofing materials. Gravimetric analysis ofthe samples of ammonium nitrate coated with eight different waterproofing materials, vis-a-vis, uncoated ammonium nitrate, were conducted at different relative humidity and exposuretime. The results indicate that mineral jelly is the promising waterproofing material for ammonium nitrate among the materials te...
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49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.
2010-10-01
... 49 Transportation 2 2010-10-01 2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...
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Gerards, S.; Duyts, H.; Laanbroek, H.J.
1998-01-01
Ammonia-oxidising bacteria are poor competitors for limiting amounts of ammonium. Hence, starvation for ammonium seems to be the regular condition for these bacteria in natural environments. Long-term survival in the absence of ammonium will be dependent on the ability to maintain large population
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Study of stripping cristallization processus of AUC with ammonium carbonate
International Nuclear Information System (INIS)
Chegrouche, Salah.
1987-09-01
This study is concerned with direct crystallization of ammonium uranyl carbonate (AUC) from a uranium loaded organic phase (30% TBP in kerosene), with ammonium carbonate (NH 4 ) 2 CO 3 . The effects of operating conditions ((NH 4 ) 2 CO 3 concentration, flow-ratio, residence time, temperature) on the physical properties of AUC crystals (particle size distribution, specific surface, density...) are reported. All products were identified (both by chemical analysis, X-Ray diffraction) as being ammonium uranyl carbonate crystals (AUC). The results show that a high phase ratio and (NH 4 ) 2 CO 3 concentration favor the formation of fine AUC grains and aggregates. This is due mainly to the high concentration of NH + 4 in the system which leads to a high solution supersaturation and consequently to a rapid formation rate of crystal (germination). The reverse phenomenon is observed at low phase ratio and (NH 4 ) 2 CO 3 concentration, where germination and crystal growth are slow and the product is mainly monocrystal. In the intermediate range, a mixture of polycrystal and aggregates is obtained. Residence and temperature are also shown to have an effect on the processes (the effect of time being more important than temperature). In the course of this study a bench-scale stripper-crystallizer was developped and operated successfully. (author). tables, graphs
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Ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography.
Pesek, Joseph J; Matyska, Maria T
2015-07-03
The use of ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography with silica hydride-based stationary phases and mass spectrometry detection is evaluated. Retention times, peak shape, efficiency and peak intensity are compared to the more standard additives formic acid and ammonium formate. The test solutes were NAD, 3-hydroxyglutaric acid, α-ketoglutaric acid, p-aminohippuric acid, AMP, ATP, aconitic acid, threonine, N-acetyl carnitine, and 3-methyladipic acid. The column parameters are assessed in both the positive and negative ion detection modes. Ammonium fluoride is potentially an aggressive mobile phase additive that could have detrimental effects on column lifetime. Column reproducibility is measured and the effects of switching between different additives are also tested. Copyright © 2015 Elsevier B.V. All rights reserved.
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Exciplex emission from amphiphilic polysilanes bearing ammonium moieties
International Nuclear Information System (INIS)
Yamaki, T.; Nakashiba, Y.; Asai, K.; Ishigure, K.; Shibata, H.
1997-01-01
We were the first to observe two emission bands in the visible region for some kinds of ammonium-type amphiphilic polysilanes both in solutions and in thin films. One, a broad emission band at 400-500 nm not due to a σ * →σ transition, was observed only for methylphenylsilane-based polymer solutions. The appearance of this low-energy emission is reasonably explained by considering the intramolecular exciplex formation between a Si-conjugated main chain and an ammonium site in the same monomer unit. The other, an emission band at the longer wavelength (around 560 nm), was found in the solvent-cast films where each molecule is randomly located, in addition to that observed for the solutions. This emission, which was not observed for the oriented LB films, is considered to originate from an intermolecular interaction. (orig.)
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Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials
Directory of Open Access Journals (Sweden)
Jianli Yang
2017-01-01
Full Text Available The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3 has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed.
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Novel Ammonium Metal Borohydrides
DEFF Research Database (Denmark)
Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan
, it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed......, and the crystal structures and thermal decompositions are investigated. Mixtures of NH4BH4 - NaBH4 do not react, while solid solutions, K1-x(NH4)xBH4, are formed for NH4BH4 - KBH4. For the other composites, novel ammonium metal borohydrides are formed. Several of these structures have been solved from high...
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Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces.
Oze, Christopher; Jones, L Camille; Goldsmith, Jonas I; Rosenbauer, Robert J
2012-06-19
Molecular hydrogen (H(2)) is derived from the hydrothermal alteration of olivine-rich planetary crust. Abiotic and biotic processes consume H(2) to produce methane (CH(4)); however, the extent of either process is unknown. Here, we assess the temporal dependence and limit of abiotic CH(4) related to the presence and formation of mineral catalysts during olivine hydrolysis (i.e., serpentinization) at 200 °C and 0.03 gigapascal. Results indicate that the rate of CH(4) production increases to a maximum value related to magnetite catalyzation. By identifying the dynamics of CH(4) production, we kinetically model how the H(2) to CH(4) ratio may be used to assess the origin of CH(4) in deep subsurface serpentinization systems on Earth and Mars. Based on our model and available field data, low H(2)/CH(4) ratios (less than approximately 40) indicate that life is likely present and active.
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21 CFR 184.1138 - Ammonium chloride.
2010-04-01
... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The...
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Abiotic versus biotic controls on soil nitrogen cycling in drylands along a 3200 km transect
Liu, Dongwei; Zhu, Weixing; Wang, Xiaobo; Pan, Yuepeng; Wang, Chao; Xi, Dan; Bai, Edith; Wang, Yuesi; Han, Xingguo; Fang, Yunting
2017-03-01
Nitrogen (N) cycling in drylands under changing climate is not well understood. Our understanding of N cycling over larger scales to date relies heavily on the measurement of bulk soil N, and the information about internal soil N transformations remains limited. The 15N natural abundance (δ15N) of ammonium and nitrate can serve as a proxy record for the N processes in soils. To better understand the patterns and mechanisms of N cycling in drylands, we collected soils along a 3200 km transect at about 100 km intervals in northern China, with mean annual precipitation (MAP) ranging from 36 to 436 mm. We analyzed N pools and δ15N of ammonium, dual isotopes (15N and 18O) of nitrate, and the microbial gene abundance associated with soil N transformations. We found that N status and its driving factors were different above and below a MAP threshold of 100 mm. In the arid zone with MAP below 100 mm, soil inorganic N accumulated, with a large fraction being of atmospheric origin, and ammonia volatilization was strong in soils with high pH. In addition, the abundance of microbial genes associated with soil N transformations was low. In the semiarid zone with MAP above 100 mm, soil inorganic N concentrations were low and were controlled mainly by biological processes (e.g., plant uptake and denitrification). The preference for soil ammonium over nitrate by the dominant plant species may enhance the possibility of soil nitrate losses via denitrification. Overall, our study suggests that a shift from abiotic to biotic controls on soil N biogeochemistry under global climate changes would greatly affect N losses, soil N availability, and other N transformation processes in these drylands in China.
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Mihai, Oana; Tamm, Stefanie; Stenfeldt, Marie; Olsson, Louise
2016-02-28
A selective catalytic reduction (SCR)-coated particulate filter was evaluated by means of dynamic tests performed using NH3, NO2, O2 and H2O. The reactions were examined both prior to and after soot removal in order to study the effect of soot on ammonium nitrate formation and decomposition, ammonia storage and NO2 SCR. A slightly larger ammonia storage capacity was observed when soot was present in the sample, which indicated that small amounts of ammonia can adsorb on the soot. Feeding of NO2 and NH3 in the presence of O2 and H2O at low temperature (150, 175 and 200°C) leads to a large formation of ammonium nitrate species and during the subsequent temperature ramp using H2O and argon, a production of nitrous oxides was observed. The N2O formation is often related to ammonium nitrate decomposition, and our results showed that the N2O formation was clearly decreased by the presence of soot. We therefore propose that in the presence of soot, there are fewer ammonium nitrate species on the surface due to the interactions with the soot. Indeed, we do observe CO2 production during the reaction conditions also at 150°C, which shows that there is a reaction with these species and soot. In addition, the conversion of NOx due to NO2 SCR was significantly enhanced in the presence of soot; we attribute this to the smaller amount of ammonium nitrate species present in the experiments where soot is available since it is well known that ammonium nitrate formation is a major problem at low temperature due to the blocking of the catalytic sites. Further, a scanning electron microscopy analysis of the soot particles shows that they are about 30-40 nm and are therefore too large to enter the pores of the zeolites. There are likely CuxOy or other copper species available on the outside of the zeolite crystallites, which could have been enhanced due to the hydrothermal treatment at 850°C of the SCR-coated filter prior to the soot loading. We therefore propose that soot is
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Novel Ammonium Metal Borohydrides
DEFF Research Database (Denmark)
Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan
Ammonium borohydride, NH4BH4, has a very high gravimetric (ρm = 24.5 wt% H2) and volumetric (157.3 g·H2/L) hydrogen content and releases 18.4 wt% H2 below 170 °C. However, NH4BH4 is metastable at RT and ambient pressure, with a half-life of ~6 h. The decomposition is strongly exothermic; therefore......, it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed...
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SERDP ER-1421 Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA: Final Report
Energy Technology Data Exchange (ETDEWEB)
Szecsody, James E.; McKinley, James P.; Crocker, Fiona H.; Breshears, Andrew T.; Devary, Brooks J.; Fredrickson, Herbert L.; Thompson, Karen T.
2009-09-30
This laboratory-scale project was initiated to investigate in situ abiotic/biotic mineralization of NDMA. Under iron-reducing conditions, aquifer sediments showed rapid abiotic NDMA degradation to dimethylamine (DMA), nitrate, formate, and finally, CO2. These are the first reported experiments of abiotic NDMA mineralization. The NDMA reactivity of these different iron phases showed that adsorbed ferrous iron was the dominant reactive phase that promoted NDMA reduction, and other ferrous phases present (siderite, iron sulfide, magnetite, structural ferrous iron in 2:1 clays) did not promote NDMA degradation. In contrast, oxic sediments that were biostimulated with propane promoted biomineralization of NDMA by a cometabolic monooxygenase enzyme process. Other monooxygenase enzyme processes were not stimulated with methane or toluene additions, and acetylene addition did not block mineralization. Although NDMA mineralization extent was the highest in oxic, biostimulated sediments (30 to 82%, compared to 10 to 26% for abiotic mineralization in reduced sediments), large 1-D column studies (high sediment/water ratio of aquifers) showed 5.6 times higher NDMA mineralization rates in reduced sediment (half-life 410 ± 147 h) than oxic biomineralization (half life 2293 ± 1866 h). Sequential reduced/oxic biostimulated sediment mineralization (half-life 3180 ± 1094 h) was also inefficient compared to reduced sediment. These promising laboratory-scale results for NDMA mineralization should be investigated at field scale. Future studies of NDMA remediation should focus on the comparison of this in situ abiotic NDMA mineralization (iron-reducing environments) to ex situ biomineralization, which has been shown successful in other studies.
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Energy Technology Data Exchange (ETDEWEB)
Fernandes, Nelmo Furtado; Cunha, Fabiana A; Alvise, Paulo Pio [PETROBRAS, Rio de Janeiro, RJ (Brazil)
2008-07-01
Fouling and consequent under deposit corrosion caused by ammonium salts, especially ammonium chloride, have serious impact on the reliability of operation of various process units. In hydrotreating units salt deposition on heat exchanger tubes causes a decrease in heat transfer efficiency, decrease hydrotreating efficiency, increased pressure drops, and corrosion. This paper will discuss the causes of ammonium chloride fouling,methods to help prevent and/or mitigate the fouling, and provide a case history demonstrating the effects of ammonium chloride formations in one refinery operation. (author)
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Safety aspects of genetically modified crops with abiotic stress tolerance
Liang, C.; Prins, T.W.; Wiel, van de C.C.M.; Kok, E.J.
2014-01-01
Abiotic stress, such as drought, salinity, and temperature extremes, significantly reduce crop yields. Hence, development of abiotic stress-tolerant crops by modern biotechnology may contribute to global food security. Prior to introducing genetically modified crops with abiotic stress tolerance to
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Ammonium generation during SRAT cycle
International Nuclear Information System (INIS)
Hsu, C.W.
1992-01-01
During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle
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Zazoua, A; Kazane, I; Khedimallah, N; Dernane, C; Errachid, A; Jaffrezic-Renault, N
2013-12-01
Ammonium exchange with hybrid PVC-bentonite (mineral montmorillonite clay) thin film was revealed using FTIR spectroscopy, EDX, cyclic voltammetry and electrochemical impedance spectroscopy. The effect of ammonium exchange on the charge transfer resistance of PVC-bentonite hybrid thin film was attributed to a modification of the intersheet distance and hydration of bentonite crystals. The obtained impedimetric ammonium sensor shows a linear range of detection from 10(-4)M to 1M and a detection limit around 10(-6)M. © 2013.
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Abscisic Acid and Abiotic Stress Signaling
Tuteja, Narendra
2007-01-01
Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant ...
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Resilience of cereal crops to abiotic stress: A review | Ahmad ...
African Journals Online (AJOL)
In the last century, conventional selection and breeding program proved to be highly effective in improving crops against abiotic stresses. Therefore, breeding for abiotic stress tolerance in crop plants should be given high research priority as abiotic stresses are the main factor negatively affecting crop growth and ...
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Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars
International Nuclear Information System (INIS)
Cui, Xiaoqiang; Hao, Hulin; Zhang, Changkuan; He, Zhenli; Yang, Xiaoe
2016-01-01
The objective of this study was to investigate the relationship between Cd 2+ /NH 4 + sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH 4 + and Cd 2+ , with a maximum sorption of 13.35 and 125.8 mg g −1 , respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g −1 ) for Cd 2+ . Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd 2+ sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd 2+ . • NH 4 + and Cd 2+ sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.
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Capacity and mechanisms of ammonium and cadmium sorption on different wetland-plant derived biochars
Energy Technology Data Exchange (ETDEWEB)
Cui, Xiaoqiang [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Hao, Hulin [Ningbo Raw Water Resource Research Academy, Ningbo (China); Zhang, Changkuan [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); He, Zhenli [Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945 (United States); Yang, Xiaoe, E-mail: xyang571@yahoo.com [Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)
2016-01-01
The objective of this study was to investigate the relationship between Cd{sup 2+}/NH{sub 4}{sup +} sorption and physicochemical properties of biochars produced from different wetland plants. Biochars from six species of wetland plants (i.e., Canna indica, Pennisetum purpureum Schum, Thalia dealbata, Zizania caduciflora, Phragmites australis and Vetiveria zizanioides) were obtained at 500 °C and characterized, and their sorption for ammonium and cadmium was determined. There were significant differences in elemental composition, functional groups and specific surface area among the biochars derived from different wetland plant species. Sorption of ammonium and cadmium on the biochars could be described by a pseudo second order kinetic model, and the simple Langmuir model fits the isotherm data better than the Freundlich or Temkin model. The C. indica derived biochar had the largest sorption capacity for NH{sub 4}{sup +} and Cd{sup 2+}, with a maximum sorption of 13.35 and 125.8 mg g{sup −1}, respectively. P. purpureum Schum derived biochar had a similar maximum sorption (119.3 mg g{sup −1}) for Cd{sup 2+}. Ammonium sorption was mainly controlled by cation exchange, surface complexation with oxygen-containing functional groups and the formation of magnesium ammonium phosphate compounds, whereas for Cd{sup 2+} sorption, the formation of cadmium phosphate precipitates, cation exchange and binding to oxygen-containing groups were the major possible mechanisms. In addition, the sorption of ammonium and cadmium was not affected by surface area and microporosity of the biochars. - Highlights: • Biochars varied in physicochemical properties and adsorption capacity. • Canna indica derived biochar has a high sorption capacity for Cd{sup 2+}. • NH{sub 4}{sup +} and Cd{sup 2+} sorption on biochars fits a pseudo second order and Langmuir model. • Sorption mechanism is related to complexation, cation exchange and precipitation.
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Glufosinate ammonium selection of transformed Arabidopsis.
Weigel, Detlef; Glazebrook, Jane
2006-12-01
INTRODUCTIONOne of the most commonly used markers for the selection of transgenic Arabidopsis is resistance to glufosinate ammonium, an herbicide that is sold under a variety of trade names including Basta and Finale. Resistance to glufosinate ammonium is conferred by the bacterial bialophos resistance gene (BAR) encoding the enzyme phosphinotricin acetyl transferase (PAT). This protocol describes the use of glufosinate ammonium to select transformed Arabidopsis plants. The major advantage of glufosinate ammonium selection is that it can be performed on plants growing in soil and does not require the use of sterile techniques.
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The Abiotic Depletion Potential: Background, Updates, and Future
Directory of Open Access Journals (Sweden)
Lauran van Oers
2016-03-01
Full Text Available Depletion of abiotic resources is a much disputed impact category in life cycle assessment (LCA. The reason is that the problem can be defined in different ways. Furthermore, within a specified problem definition, many choices can still be made regarding which parameters to include in the characterization model and which data to use. This article gives an overview of the problem definition and the choices that have been made when defining the abiotic depletion potentials (ADPs for a characterization model for abiotic resource depletion in LCA. Updates of the ADPs since 2002 are also briefly discussed. Finally, some possible new developments of the impact category of abiotic resource depletion are suggested, such as redefining the depletion problem as a dilution problem. This means taking the reserves in the environment and the economy into account in the reserve parameter and using leakage from the economy, instead of extraction rate, as a dilution parameter.
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Energy Technology Data Exchange (ETDEWEB)
Fernandes, Nelmo Furtado; Cunha, Fabiana A.; Alvise, Paulo Pio [PETROBRAS, Rio de Janeiro, RJ (Brazil)
2008-07-01
Fouling and consequent under deposit corrosion caused by ammonium salts, especially ammonium chloride, have serious impact on the reliability of operation of various process units. In hydrotreating units salt deposition on heat exchanger tubes causes a decrease in heat transfer efficiency, decrease hydrotreating efficiency, increased pressure drops, and corrosion. This paper will discuss the causes of ammonium chloride fouling,methods to help prevent and/or mitigate the fouling, and provide a case history demonstrating the effects of ammonium chloride formations in one refinery operation. (author)
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Directory of Open Access Journals (Sweden)
OANA E. CONSTANTIN
2016-07-01
Full Text Available Considering the well-known mechanism of adaptable resistance of microorganisms to chemical compounds through biofilms formation and the widespread use of N-heterocyclic quaternary ammonium salts (QAC as disinfectants, in this study we have evaluate the effect of 8 newly synthesized symmetrical and unsymmetrical diquaternary ammonium salts of 1,2-bis-(4-pyridil-ethane on bacterial biofilms produced by three different bacterial strains. The effect of the exposure to quaternary ammonium salts on biofilm communities was investigated within biofilms obtained in a conventional testing system, on stainless steel and glass surfaces. Differential plate counts were used to characterize the developed communities and the effects of QAC exposure and the results were correlated with epifluorescence microphotographs. The data obtained revealed a significant reduction of bacterial cells in the biofilms tested with 4-7 log CFU for all the QAC.
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Abiotic stress miRNomes in the Triticeae
Alptekin, Burcu; Langridge, Peter; Budak, Hikmet
2016-01-01
The continued growth in world population necessitates increases in both the quantity and quality of agricultural production. Triticeae members, particularly wheat and barley, make an important contribution to world food reserves by providing rich sources of carbohydrate and protein. These crops are grown over diverse production environments that are characterized by a range of environmental or abiotic stresses. Abiotic stresses such as drought, heat, salinity, or nutrient deficiencies and tox...
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Huang, Bin; Gu, Lipeng; He, Huan; Xu, Zhixiang; Pan, Xuejun
2016-09-14
This study investigated the simultaneous transformation of Cr(vi) via a closely coupled biotic and abiotic pathway in an anaerobic system of quinone-reducing bacteria/dissolved organic matters (DOM)/Fe(iii). Batch studies were conducted with quinone-reducing bacteria to assess the influences of sodium formate (NaFc), electron shuttling compounds (DOM) and the Fe(iii) on Cr(vi) reduction rates as these chemical species are likely to be present in the environment during in situ bioremediation. Results indicated that the concentration of sodium formate and anthraquinone-2-sodium sulfonate (AQS) had apparently an effect on Cr(vi) reduction. The fastest decrease in rate for incubation supplemented with 5 mM sodium formate and 0.8 mM AQS showed that Fe(iii)/DOM significantly promoted the reduction of Cr(vi). Presumably due to the presence of more easily utilizable sodium formate, DOM and Fe(iii) have indirect Cr(vi) reduction capability. The coexisting cycles of Fe(ii)/Fe(iii) and DOM(ox)/DOM(red) exhibited a higher redox function than the individual cycle, and their abiotic coupling action can significantly enhance Cr(vi) reduction by quinone-reducing bacteria.
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Protection of the Abiotic Environment
International Nuclear Information System (INIS)
Michel, R.; Hutmacher, K. E.; Landfermann, H. H.
2004-01-01
Environmental protection against the dangers arising from ionizing radiation, radioactive materials, and other harmful substances is more than to avoid acute dangers or risks for humans or for non-human living organisms. To allow for a sustainable development the abiotic part of the environment must not be neglected in concepts of environmental protection. The environmental impact of some selected long-lived anthropogenic radionuclides is used to exemplify adverse effects for which a unified approach is needed. To this end, indicators are needed for the assessment of the human impact on the abiotic environment which allows to compare different human actions with respect to sustainability and to choose appropriate measures in the competition for a sustainable development. Such indicators have to account for the dynamics of the different environmental compartments. Using the long-lived radionuclides 14C, 36Cl, 85Kr, and 129I as examples, the importance to consider dynamical models and ecological lifetimes in quantifications of the human impact on the environment is emphasized. Particular problems arise from the natural occurrences and variability of radionuclides and other harmful substances. Suitable indicators for the assessment of human impact on the abiotic compartments air, water, and soil are discussed. (Author) 18 refs
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Polyamines and abiotic stress in plants: A complex relationship
Directory of Open Access Journals (Sweden)
Rakesh eMinocha
2014-05-01
Full Text Available The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g. due to their ability to deal with oxidative radicals or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism. The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e. being a protector as well as a perpetrator of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress.
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Producing ammonium chloride from coal or shale
Energy Technology Data Exchange (ETDEWEB)
Christenson, O L
1921-02-25
Process of producing ammonium chloride consists of mixing the substance to be treated with a chloride of an alkali or alkaline earth metal, free silica, water and free hydrochloric acid, heating the mixture until ammonium chloride distills off and collecting the ammonium chloride.
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International Nuclear Information System (INIS)
Sun, Zhi-Gao; Jiao, Li-Jun; Zhao, Zhi-Gui; Wang, Gong-Liang; Huang, Hai-Feng
2014-01-01
Highlights: • Carbon dioxide hydrate stability zone was enlarged with the help of TBAC. • Carbon dioxide uptake into TBAC semi-clathrate hydrates is confirmed. • Equilibrium pressure of hydrate decreased with the increase of TBAC mass concentration. • The addition of TBAC reduces the formation pressures of carbon dioxide hydrate by 2.5 MPa. - Abstract: In the present work, hydrate equilibrium conditions for (tetra-n-butyl ammonium chloride (TBAC) + carbon dioxide + water) mixtures were investigated. Tetra-n-butyl ammonium chloride was reported to form a semi-clathrate hydrate. The experiments were carried out within the TBAC mass fraction range of (0.05 to 0.3). The experimental results showed that the presence of TBAC decreased the formation pressure of carbon dioxide double hydrate within the experimental temperature range. Moreover, pressure reduction was dependent on the TBAC concentration
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Life without water: cross-resistance of anhydrobiotic cell line to abiotic stresses
Gusev, Oleg
2016-07-01
Anhydrobiosis is an intriguing phenomenon of natural ability of some organisms to resist water loss. The larvae of Polypedilum vanderplanki, the sleeping chironomid is the largest and most complex anhydrobionts known to date. The larvae showed ability to survive variety of abiotic stresses, including outer space environment. Recently cell line (Pv11) derived from the embryonic mass of the chironomid was established. Initially sensitive to desiccation cells, are capable to "induced" anhydrobiosis, when the resistance to desiccation can be developed by pre-treatment of the cells with trehalose followed by quick desiccation. We have further conducted complex analysis of the whole genome transcription response of Pv11 cells to different abiotic stresses, including oxidative stress and irradiation. Comparative analysis showed that the gene set, responsible for formation of desiccation resistance (ARID regions in the genome) is also activated in response to other types of stresses and likely to contribute to general enhancing of the resistance of the cells to harsh environment. We have further demonstrated that the cells are able to protect recombinant proteins from harmful effect of desiccation
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Ammonium nitrate-potassium nitrate system
Energy Technology Data Exchange (ETDEWEB)
Cady, H.H.
1981-01-01
A portion of the binary phase diagram for the system ammonium nitrate-potassium nitrate has been determined from -55/sup 0/C to 185/sup 0/C. Results are presented for the ammonium-nitrate-rich end of the system up to 30 wt% potassium nitrate.
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Hydroxylated PCBs in abiotic environmental matrices. Precipitation and surface waters
Energy Technology Data Exchange (ETDEWEB)
Darling, C.; Alaee, M.; Campbell, L.; Pacepavicius, G.; Ueno, D.; Muir, D. [National Water Research Institute, Burlington, ON (Canada)
2004-09-15
Hydroxylated PCBs (OH-PCBs) are of great interest environmentally because of their potential thyroidogenic effects. OH-PCBs can compete with thyroxine for binding sites on transthyretin, one of the three main thyroid hormone transport proteins in mammals1. The chemical structures of some OH-PCBs with a para OH group and adjacent chlorine atoms, particularly 4-OH-CB109, 4- OH-CB146, and 4-OH-CB187, share a similar structure to the thyroid hormones (T3 and T4), which have a para OH with adjacent iodine atoms. A number of OH-PCBs have been identified in the blood of humans and biota during the last 5 to 10 years, however, reports on the identity, presence and levels of OH-PCBs are limited. This presentation describes preliminary studies on the presence of OH-PCBs in abiotic samples and comparisons of congener patterns with biological samples. We have previously shown that OHPCBs were present in lake trout from the Great Lakes and nearby large lakes as well as in nearshore environments. We hypothesized that some of the OH-PCB present in fish might be from abiotic formation in water or the atmosphere, or from microbial oxidation of PCBs and/or deconjugation of PCB metabolites in waste treatment plants.
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Holm, Nils G; Neubeck, Anna
2009-10-22
Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.
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Directory of Open Access Journals (Sweden)
Neubeck Anna
2009-10-01
Full Text Available Abstract Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.
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Designing cooperatively folded abiotic uni- and multimolecular helix bundles
de, Soumen; Chi, Bo; Granier, Thierry; Qi, Ting; Maurizot, Victor; Huc, Ivan
2018-01-01
Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix-turn-helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix-turn-helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.
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Deeply-sourced formate fuels sulfate reducers but not methanogens at Lost City hydrothermal field.
Lang, Susan Q; Früh-Green, Gretchen L; Bernasconi, Stefano M; Brazelton, William J; Schrenk, Matthew O; McGonigle, Julia M
2018-01-15
Hydrogen produced during water-rock serpentinization reactions can drive the synthesis of organic compounds both biotically and abiotically. We investigated abiotic carbon production and microbial metabolic pathways at the high energy but low diversity serpentinite-hosted Lost City hydrothermal field. Compound-specific 14 C data demonstrates that formate is mantle-derived and abiotic in some locations and has an additional, seawater-derived component in others. Lipids produced by the dominant member of the archaeal community, the Lost City Methanosarcinales, largely lack 14 C, but metagenomic evidence suggests they cannot use formate for methanogenesis. Instead, sulfate-reducing bacteria may be the primary consumers of formate in Lost City chimneys. Paradoxically, the archaeal phylotype that numerically dominates the chimney microbial communities appears ill suited to live in pure hydrothermal fluids without the co-occurrence of organisms that can liberate CO 2 . Considering the lack of dissolved inorganic carbon in such systems, the ability to utilize formate may be a key trait for survival in pristine serpentinite-hosted environments.
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International Nuclear Information System (INIS)
Stockwell, W.R.; Watson, J.G.; Robinson, N.F.; Sylte, W.W.
2000-01-01
A new method has been developed to assess the aerosol particle formation reactivity of nitrogen oxide (NO x ) emissions. The method involves using a photochemical box model with gas-phase photochemistry, aerosol production and deposition to calculate the ammonium nitrate particle equivalent of NO x emissions. The yields of ammonium nitrate particles used in the box model were determined from parametric simulations made with an equilibrium model that calculated the fraction of nitric acid that reacts to produce ammonium nitrate from the temperature, relative humidity and ammonium-to-nitrate ratios. For the wintertime conditions of emissions and meteorology in the San Joaquin Valley of central California, approximately 80% of the moles of nitric acid produced was found to be in the particulate nitrate phase and about 33% of the moles of emitted NO x was converted to particulate nitrate. The particle equivalent of NO x emissions was found to be on the order of 0.6 g of ammonium nitrate for each gram of NO x emitted (the mass of NO x calculated as NO 2 ). This estimate is in reasonable agreement with an analysis of field measurements made in central California. (author)
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Growth, viability and architecture of biofilms of Listeria monocytogenes formed on abiotic surfaces
Directory of Open Access Journals (Sweden)
Fernanda Barbosa dos Reis-Teixeira
Full Text Available Abstract The pathogenic bacterium Listeria monocytogenes can persist in food processing plants for many years, even when appropriate hygienic measures are in place, with potential for contaminating ready-to-eat products and, its ability to form biofilms on abiotic surfaces certainly contributes for the environmental persistence. In this research, L. monocytogenes was grown in biofilms up 8 days attached to stainless steel and glass surfaces, contributing for advancing the knowledge on architecture of mature biofilms, since many literature studies carried out on this topic considered only early stages of cell adhesion. In this study, biofilm populations of two strains of L. monocytogenes (serotypes 1/2a and 4b on stainless steel coupons and glass were examined using regular fluorescence microscopy, confocal laser scanning microscopy and classic culture method. The biofilms formed were not very dense and microscopic observations revealed uneven biofilm structures, with presence of exopolymeric matrix surrounding single cells, small aggregates and microcolonies, in a honeycomb-like arrangement. Moreover, planktonic population of L. monocytogenes (present in broth media covering the abiotic surface remained stable throughout the incubation time, which indicates an efficient dispersal mechanism, since the culture medium was replaced daily. In conclusion, even if these strains of L. monocytogenes were not able to form thick multilayer biofilms, it was noticeable their high persistence on abiotic surfaces, reinforcing the need to focus on measures to avoid biofilm formation, instead of trying to eradicate mature biofilms.
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Growth, viability and architecture of biofilms of Listeria monocytogenes formed on abiotic surfaces.
Reis-Teixeira, Fernanda Barbosa Dos; Alves, Virgínia Farias; de Martinis, Elaine Cristina Pereira
The pathogenic bacterium Listeria monocytogenes can persist in food processing plants for many years, even when appropriate hygienic measures are in place, with potential for contaminating ready-to-eat products and, its ability to form biofilms on abiotic surfaces certainly contributes for the environmental persistence. In this research, L. monocytogenes was grown in biofilms up 8 days attached to stainless steel and glass surfaces, contributing for advancing the knowledge on architecture of mature biofilms, since many literature studies carried out on this topic considered only early stages of cell adhesion. In this study, biofilm populations of two strains of L. monocytogenes (serotypes 1/2a and 4b) on stainless steel coupons and glass were examined using regular fluorescence microscopy, confocal laser scanning microscopy and classic culture method. The biofilms formed were not very dense and microscopic observations revealed uneven biofilm structures, with presence of exopolymeric matrix surrounding single cells, small aggregates and microcolonies, in a honeycomb-like arrangement. Moreover, planktonic population of L. monocytogenes (present in broth media covering the abiotic surface) remained stable throughout the incubation time, which indicates an efficient dispersal mechanism, since the culture medium was replaced daily. In conclusion, even if these strains of L. monocytogenes were not able to form thick multilayer biofilms, it was noticeable their high persistence on abiotic surfaces, reinforcing the need to focus on measures to avoid biofilm formation, instead of trying to eradicate mature biofilms. Copyright © 2017. Published by Elsevier Editora Ltda.
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Generation of RNA in abiotic conditions.
di Mauro, Ernesto
Generation of RNA in abiotic conditions. Ernesto Di Mauro Dipartimento di Genetica Bi-ologia Molecolare, Universit` "Sapienza" Roma, Italy. a At least four conditions must be satisfied for the spontaneous generation of (pre)-genetic poly-mers: 1) availability of precursors that are activated enough to spontaneously polymerize. Preliminary studies showed that (a) nucleic bases and acyclonucleosides can be synthesized from formamide H2NCOH by simply heating with prebiotically available mineral catalysts [last reviewed in (1)], and that b) nucleic bases can be phosphorylated in every possible posi-tion [2'; 3'; 5'; cyclic 2',3'; cyclic 3',5' (2)]. The higher stability of the cyclic forms allows their accumulation. 2) A polymerization mechanism. A reaction showing the formation of RNA polymers starting from prebiotically plausible precursors (3',5' cyclic GMP and 3', 5'cyclic AMP) was recently reported (3). Polymerization in these conditions is thermodynamically up-hill and an equilibrium is attained that limits the maximum length of the polymer produced to about 40 nucleotides for polyG and 100 nucleotides for polyA. 3) Ligation of the synthesized oligomers. If this type of reaction could occur according to a terminal-joining mechanism and could generate canonical 3',5' phosphodiester bonds, exponential growth would be obtained of the generated oligomers. This type of reaction has been reported (4) , limited to homogeneous polyA sequences and leading to the production of polyA dimers and tetramers. What is still missing are: 4) mechanisms that provide the proof of principle for the generation of sequence complexity. We will show evidence for two mechanisms providing this proof of principle for simple complementary sequences. Namely: abiotic sequence complementary-driven terminal ligation and sequence-complementary terminal growth. In conclusion: all the steps leading to the generation of RNA in abiotic conditions are satisfied. (1) R Saladino, C Crestini, F
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Sources et marché du sulfate d'ammonium Sources of and Market for Ammonium Sulfate
Directory of Open Access Journals (Sweden)
Loussouarn C.
2006-11-01
Full Text Available Engrais azoté le plus utilisé dans le monde jusqu'en 1970, le sulfate d'ammonium ne représente plus aujourd'hui que 4 % de la fertilisation azotée. Avec une teneur en azote de 21 % seulement, il a été peu à peu remplacé comme engrais universel par des produits plus concentrés, notamment l'urée et le nitrate d'ammonium. Obtenu pour plus de 40 % comme sous-produit dans la synthèse de monomères comme le caprolactame, l'acrylonitrile ou le méthacrylate de méthyle, et pour près de 10 % dans le traitement des gaz de cokerie, sa production dépend largement des développements du marché des fibres synthétiques, et, dans une moindre mesure, de la sidérurgie et de la métallurgie. Dans les pays développés, où la production est essentiellement fatale, le volume du marché est et sera plus fonction de la disponibilité du sulfate d'ammonium que de la demande ou de facteurs de marché; sa consommation ne résidera plus que dans des applications spécifiques pour lesquelles il sera bien adapté. Par contre, l'intérêt croissant pour compenser le déficit en soufre de certains sols, et les qualités agronomiques propres du sulfate d'ammonium laissent entrevoir la possibilité d'un essor de son utilisation dans certaines régions en voie de développernent. Ammonium sulfate was the most worldwide nitrogenous fertilizer used up to 1970. Today, it makes up only 4% of nitrogenous fertilization. With a nitrogen content of only 21%, it has gradually been replaced as a universal fertilizer by more concentrated products, particularly urea and ammonium nitrate. More than 40% of the ammonium sulfate is obtained as a by-product from the synthesis of monomers such as caprolactam, acrylonitrile or methyl methacrylate, and nearly 10% from coking gas processing. Its production depends extensively on the development of the market for synthetic fibers and, to a lesser extent, on the steel and metallurgical industries. In the industrialized countries
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Ammonium-tungstate-promoted growth of boron nitride nanotubes
E, Songfeng; Li, Chaowei; Li, Taotao; Geng, Renjie; Li, Qiulong; Lu, Weibang; Yao, Yagang
2018-05-01
Ammonium tungstate ((NH4)10W12O41 · xH2O) is a kind of oxygen-containing ammonium salt. The following study proves that it can be successfully used as a metal oxide alternative to produce boron oxide (B2O2) by oxidizing boron (B) in a traditional boron oxide chemical vapor deposition (BOCVD) process. This special oxidant promotes the simplistic fabrication of boron nitride nanotubes (BNNTs) in a conventional horizontal tube furnace, an outcome which may have resulted from its strong oxidizability. The experimental results demonstrate that the mole ratio of B and (NH4)10W12O41 · xH2O is a key parameter in determining the formation, quality and quantity of BNNTs when stainless steel is employed as a catalyst. We also found that Mg(NO3)2 and MgO nanoparticles (NPs) can be used as catalysts to grow BNNTs with the same precursor. The BNNTs obtained from the Mg(NO3)2 catalyst were straighter than those obtained from the MgO NP catalyst. This could have been due to the different physical forms of the catalysts that were used.
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Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong; Huang, Teng; Xu, Kang-Ming; Wen, Hui; Zhu, Yu-Peng; Huang, Wei
2015-03-26
Although ammonium ion-water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion-water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters of different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion-water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion-water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4(+)(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.
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Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress
Directory of Open Access Journals (Sweden)
Cláudia Regina Batista de Souza
2012-07-01
Full Text Available Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.
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Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants
Directory of Open Access Journals (Sweden)
Shabir H. Wani
2016-06-01
Full Text Available Abiotic stresses including drought, salinity, heat, cold, flooding, and ultraviolet radiation causes crop losses worldwide. In recent times, preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance. However, the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities. Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance. Recent investigations have shown that phytohormones, including the classical auxins, cytokinins, ethylene, and gibberellins, and newer members including brassinosteroids, jasmonates, and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants. In this review, we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance, besides their engineering for conferring abiotic stress tolerance in transgenic crops. We also describe recent successes in identifying the roles of phytohormones under stressful conditions. We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.
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Role of Biotic and Abiotic Processes on Soil CO2 Dynamics in the McMurdo Dry Valleys, Antarctica
Risk, D. A.; Macintyre, C. M.; Lee, C.; Cary, C.; Shanhun, F.; Almond, P. C.
2016-12-01
In the harsh conditions of the Antarctic Dry Valleys, microbial activity has been recorded via measurements of soil carbon dioxide (CO2) concentration and surface efflux. However, high temporal resolution studies in the Dry Valleys have also shown that abiotic solubility-driven processes can strongly influence (and perhaps even dominate) the CO2 dynamics in these low flux environments and suggests that biological activity may be lower than previously thought. In this study, we aim to improve our understanding of CO2 dynamics (biotic and abiotic) in Antarctic Dry Valley soils using long-term automated measurements of soil CO2 surface flux and soil profile concentration at several sites, often at sub-diel frequency. We hypothesize that soil CO2 variations are driven primarily by environmental factors affecting CO2 solubility in soil solution, mainly temperature, and that these processes may even overprint biologic production in representative Dry Valley soils. Monitoring of all sites revealed only one likely biotic CO2 production event, lasting three weeks during the Austral summer and reaching fluxes of 0.4 µmol/m2/s. Under more typical low flux conditions (sampling campaigns. Subsurface CO2 monitoring and a lab-controlled Antarctic soil simulation experiment confirmed that abiotic processes are capable of dominating soil CO2 variability. Diel temperature cycles crossing the freezing boundary revealed a dual abiotic cycle of solubility cycling and gas exclusion from ice formation observed only by high temporal frequency measurements (30 min). This work demonstrates a need for a numerical model to partition the dynamic abiotic processes underlying any biotic CO2 production in order to understand potential climate-change induced increases in microbial productivity in terrestrial Antarctica.
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Structure, function and networks of transcription factors involved in abiotic stress responses
DEFF Research Database (Denmark)
Lindemose, Søren; O'Shea, Charlotte; Jensen, Michael Krogh
2013-01-01
Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes...... and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based...... on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic...
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The shifting influence of abiotic drivers during landslide succession in Puerto Rico
L. R. Walker; A. B. Shiels; P. J. Bellingham; A. D. Sparrow; N. Fetcher; F. H. Landau; D. J. Lodge
2013-01-01
Summary 1. Abiotic variables are critical drivers of succession in most primary seres, but how their influence on biota changes over time is rarely examined. Landslides provide good model systems for examining abiotic influences because they are spatially and temporally heterogeneous habitats with distinct abiotic and biotic gradients and post-landslide erosion. 2. In...
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Spectrometric determination of ammonium-nitrogen with quinol in ...
African Journals Online (AJOL)
Quinol is proposed as a reagent for the spectrometric determination of ammonium-nitrogen (NH4+-N) in aqueous medium. Quinol forms a pink complex with ammonium salt in aqueous medium. Hydrogen peroxide is needed for colour accentuation. The quinol/ammonium charge transfer complex has absorption maximum ...
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Ion-selective solid-phase electrode sensitive to ammonium ions
International Nuclear Information System (INIS)
Vlasov, Yu.G.; Milonova, M.S.; Antonov, P.P.; Bychkov, E.A.; Ehfa, A.Ya.
1983-01-01
Ammonium phosphomolybdate is investigated for the purpose of using it as membrane material of ammonium-selective solid-phase electrodes. Estimation of proton mobility and ion conductivity of ammonium phosphomolybdate is performed
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Shan, Tzu-Ray; van Duin, Adri C T; Thompson, Aidan P
2014-02-27
We have developed a new ReaxFF reactive force field parametrization for ammonium nitrate. Starting with an existing nitramine/TATB ReaxFF parametrization, we optimized it to reproduce electronic structure calculations for dissociation barriers, heats of formation, and crystal structure properties of ammonium nitrate phases. We have used it to predict the isothermal pressure-volume curve and the unreacted principal Hugoniot states. The predicted isothermal pressure-volume curve for phase IV solid ammonium nitrate agreed with electronic structure calculations and experimental data within 10% error for the considered range of compression. The predicted unreacted principal Hugoniot states were approximately 17% stiffer than experimental measurements. We then simulated thermal decomposition during heating to 2500 K. Thermal decomposition pathways agreed with experimental findings.
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International Nuclear Information System (INIS)
Ostroushko, A.A.; Mikhalev, D.S.
2003-01-01
Phase relations were studied in the ammonium paratungstate - polyvinyl alcohol - water system, isothermal cross section of the phase diagram was obtained at room temperature. Visual and microscopic observations, as well as instrumental methods were used for the detection of lines of the homogeneous polymer-salt solutions existence. Concentration ratios of density of solutions, their dynamic viscosity and refractive index were studied. Area of polymer based solutions, area of salt crystallization, heterogeneous fields with two or three phases were separated. As compared with the ammonium heptamolybdate - polyvinyl alcohol - water system the increase of solubility of components under day lighting and ultraviolet radiation escaped detection. The studied system is provided properties indicative of the formation of mesomorphic phase, photochemical reduction of ions of d-metals for the occurrence of this phase is not requirement [ru
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Revisiting the Role of Plant Transcription Factors in the Battle against Abiotic Stress.
Khan, Sardar-Ali; Li, Meng-Zhan; Wang, Suo-Min; Yin, Hong-Ju
2018-05-31
Owing to diverse abiotic stresses and global climate deterioration, the agricultural production worldwide is suffering serious losses. Breeding stress-resilient crops with higher quality and yield against multiple environmental stresses via application of transgenic technologies is currently the most promising approach. Deciphering molecular principles and mining stress-associate genes that govern plant responses against abiotic stresses is one of the prerequisites to develop stress-resistant crop varieties. As molecular switches in controlling stress-responsive genes expression, transcription factors (TFs) play crucial roles in regulating various abiotic stress responses. Hence, functional analysis of TFs and their interaction partners during abiotic stresses is crucial to perceive their role in diverse signaling cascades that many researchers have continued to undertake. Here, we review current developments in understanding TFs, with particular emphasis on their functions in orchestrating plant abiotic stress responses. Further, we discuss novel molecular mechanisms of their action under abiotic stress conditions. This will provide valuable information for understanding regulatory mechanisms to engineer stress-tolerant crops.
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Electrolytic treatment of liquid waste containing ammonium nitrate
International Nuclear Information System (INIS)
Komori, R.; Ogawa, N.; Ohtsuka, K.; Ohuchi, J.
1981-01-01
A study was made on the safe decomposition of ammonium nitrate, which is the main component of α-liquid waste from plutonium fuel facilities, by means of electrolytic reduction and thermal decomposition. In the first stage, ammonium nitrate is reduced to ammonium nitrite by electrolytic reduction using an electrolyser with a cation exchange membrane as a diaphragm. In the second stage, ammonium nitrite is decomposed to N 2 and H 2 O. The alkaline region and a low temperature are preferable for electrolytic reduction and the acidic region and high temperature for thermal decomposition. A basis was established for an ammonium nitrate treatment system in aqueous solution through the operation of a bench-scale unit, and the operating data obtained was applied to the basic design of a 10-m 3 /a facility. (author)
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Decomposition of ammonium nitrate in homogeneous and catalytic denitration
International Nuclear Information System (INIS)
Anan'ev, A. V.; Tananaev, I. G.; Shilov, V. P.
2005-01-01
Ammonium nitrate is one of potentially explosive by-products of spent fuel reprocessing. Decomposition of ammonium nitrate in the HNO 3 -HCOOH system was studied in the presence or absence of Pt/SiO 2 catalyst. It was found that decomposition of ammonium nitrate is due to homogeneous noncatalytic oxidation of ammonium ion with nitrous acid generated in the HNO 3 -HCOOH system during denitration. The platinum catalyst initiates the reaction of HNO 3 with HCOOH to form HNO 2 . The regular trends were revealed and the optimal conditions of decomposition of ammonium nitrate in nitric acid solutions were found [ru
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Optimization of nutritional requirements and ammonium feeding ...
African Journals Online (AJOL)
tounukarin
2011-09-07
Sep 7, 2011 ... Statistical experiment design and data analysis were used to ... Ammonium control strategies in fed-batch fermentation showed that when ammonium concentration ... environments, combined with the real-time process para-.
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Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?
Savvides, Andreas
2015-12-15
Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.
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Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?
Savvides, Andreas; Ali, Shawkat; Tester, Mark A.; Fotopoulos, Vasileios
2015-01-01
Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.
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Adherence of staphylococcus aureus to catheter tubing inhibition by quaternary ammonium compounds.
Iyamba, Jean-Marie Liesse; Okombe, Daniel Tassa; Zakanda, Francis Nsimba; Malongo, Trésor Kimbeni; Unya, Joseph Welo; Lukukula, Cyprien Mbundu; Kikuni, Ntondo Za Balega Takaisi
2016-01-01
S. aureus is a Gram positive bacterium which is responsible for a wide range of infections. This pathogen has also the ability to adhere to biotic or abiotic surface such as central venous catheter (CVC) and to produce a biofilm. The aim of this study was to evaluate the effect of hexadecyltrimethyl ammonium bromide (HTAB) and Hexadecylbetainate chloride (HBC) on Staphylococcus aureus adherence to the catheter tubing and on bacteria growth. Broth microdilution method was used to determine the Minimal Inhibitory Concentration (MIC). The detection of slime production was done by Congo Red Agar method, and the adherence of bacteria to the catheter tubing was evaluated by the enumeration of bacteria on plate counts. The results of this study showed that the MICs of HTAB were ranged from 0.125 to 0.5 µg/mL, and those of HBC fluctuated between 2 to 8 µg/mL. HTAB and HBC inhibited bacteria adhesion on the surface of the catheter tubing. This study showed that HTAB and HBC can prevent the adherence of S. aureus strains to the surface of catheter tubing, suggesting that they could be used to prevent the risk of catheter related bloodstream infections.
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Additional insights into the adaptation of cotton plants under abiotic ...
African Journals Online (AJOL)
Abiotic stress is the primary cause of crop losses worldwide. In addition to protein coding genes, microRNAs (miRNAs) have emerged as important players in plant stress responses. Though miRNAs are key in regulating many aspects of plant developmental plasticity under abiotic stresses, very few information are available ...
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The Role of MAPK Modules and ABA during Abiotic Stress Signaling
Zé licourt, Axel de; Colcombet, Jean; Hirt, Heribert
2016-01-01
To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses
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Propionate oxidation by and methanol inhibition of anaerobic ammonium-oxidizing bacteria.
Güven, Didem; Dapena, Ana; Kartal, Boran; Schmid, Markus C; Maas, Bart; van de Pas-Schoonen, Katinka; Sozen, Seval; Mendez, Ramon; Op den Camp, Huub J M; Jetten, Mike S M; Strous, Marc; Schmidt, Ingo
2005-02-01
Anaerobic ammonium oxidation (anammox) is a recently discovered microbial pathway and a cost-effective way to remove ammonium from wastewater. Anammox bacteria have been described as obligate chemolithoautotrophs. However, many chemolithoautotrophs (i.e., nitrifiers) can use organic compounds as a supplementary carbon source. In this study, the effect of organic compounds on anammox bacteria was investigated. It was shown that alcohols inhibited anammox bacteria, while organic acids were converted by them. Methanol was the most potent inhibitor, leading to complete and irreversible loss of activity at concentrations as low as 0.5 mM. Of the organic acids acetate and propionate, propionate was consumed at a higher rate (0.8 nmol min(-1) mg of protein(-1)) by Percoll-purified anammox cells. Glucose, formate, and alanine had no effect on the anammox process. It was shown that propionate was oxidized mainly to CO(2), with nitrate and/or nitrite as the electron acceptor. The anammox bacteria carried out propionate oxidation simultaneously with anaerobic ammonium oxidation. In an anammox enrichment culture fed with propionate for 150 days, the relative amounts of anammox cells and denitrifiers did not change significantly over time, indicating that anammox bacteria could compete successfully with heterotrophic denitrifiers for propionate. In conclusion, this study shows that anammox bacteria have a more versatile metabolism than previously assumed.
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Ammannito, E.; De Sanctis, M. C.; Carrorro, F. G.; Ciarniello, M.; Combe, J. P.; De Angelis, S.; Ehlmann, B. L.; Frigeri, A.; Longobardo, A.; Mugnuolo, R.; Marchi, S.; Palomba, E.; Raymond, C. A.; Salatti, M.; Tosi, F.; Zambon, F.; Russell, C. T.
2017-12-01
Since January 2015, the surface of Ceres has been studied by the Dawn spacecraft through the measurements from the three instruments on board (1). The VIR imaging spectrometer, sensitive to the spectral range 0.25 -5.0 μm, provided information on the surficial composition of Ceres at resolutions ranging from few kilometers to about one hundred meters (2). Analysis of VIR reflectance data revealed that the average spectrum of Ceres is compatible with a mixture of low-albedo minerals, Mg- phyllosilicates, ammoniated clays, and Mg- carbonates, (3) confirming previous studies based on ground based spectra (4, 5). Mineralogical maps of the surface at about 1 km/px show that the components identified in the average spectrum are present all across the surface with variations in their relative abundance and chemical composition (6, 7). While the ammoniated clays have been already studied (6), the presence nature and distribution of additional ammoniated species has never been investigated in detail, although the spectral analysis of the bright faculae within Occator crater already revealed the potential presence of ammonium salts (8). Since the position and shape of the ammonium absorption in the VIS-NIR region are function of the hosting mineral specie (8), we did an inventory and characterization of the ammonium-rich regions, in order to analyze their spectral properties. In addition to the presence of ammonium, also the identification of the hosting species has implication for the evolution of Ceres. Our study, therefore, is a step forward in understanding of evolutionary pathway of Ceres. References: (1) Russell, C. T. et al., Science, 2016. (2) De Sanctis M.C. et al., Space Science Reviews, 2011. (3) De Sanctis M.C. et al., Nature, 2015. (4) King T. et al. Science, 1992. (5) Rivkin A.S. et al. Icarus, 2006. (6) Ammannito E. et al., Science, 2016. (7) Carrozzo F.G. et al., Science Advances, in revision. (8) De Sanctis et al., Nature, 2016. (9) Berg et al., Icarus
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Brüggemann, Martin; Hayeck, Nathalie; Bonnineau, Chloé; Pesce, Stéphane; Alpert, Peter A; Perrier, Sébastien; Zuth, Christoph; Hoffmann, Thorsten; Chen, Jianmin; George, Christian
2017-08-24
Films of biogenic compounds exposed to the atmosphere are ubiquitously found on the surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to in bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants and VOC production. In particular, irradiation of samples containing solely biofilm cells without matrix components exhibited the strongest VOC production upon irradiation. In agreement with previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy radical chemistry. Up to now, such VOC emissions were directly accounted to high biological activity in surface waters. However, the results obtained suggest that abiotic photochemistry can lead to similar emissions into the atmosphere, especially in less biologically-active regions. Furthermore, chamber experiments suggest that oxidation (O 3 /OH radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth's radiation budget.
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21 CFR 582.1135 - Ammonium bicarbonate.
2010-04-01
... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE General Purpose Food Additives § 582.1135 Ammonium bicarbonate. (a)...
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40 CFR 180.473 - Glufosinate ammonium; tolerances for residues.
2010-07-01
... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Glufosinate ammonium; tolerances for... § 180.473 Glufosinate ammonium; tolerances for residues. (a) General. Tolerances are established for residues of the herbicide glufosinate-ammonium (butanoic acid, 2-amino-4-(hydroxymethylphosphinyl...
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15N-ammonium test in clinical research
International Nuclear Information System (INIS)
Jung, K.; Metzner, C.; Teichmann, B.; Leipzig Univ.
1989-01-01
By use of the 15 N-ammonium test the liver function is investigated under influence of hormonal contraceptives in women and in liver diseases in children. With the described noninvasive nonradioactive isotope test the ammonia detoxification capability and the urea synthesis capacity of the liver is determined by measuring of the 15 N excretion in ammonia and urea in urine after oral administering of 15 N-ammonium chloride. The 15 N-ammonium test shows a significant influence of the hormonal contraceptives on the liver function and gives diagnostic evidence for liver diseases in children. (author)
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Subcellular localization of ammonium transporters in Dictyostelium discoideum
Directory of Open Access Journals (Sweden)
Davis Carter T
2008-12-01
Full Text Available Abstract Background With the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional purposes. Dictyostelium discoideum has three ammonium transporters, Amts A, B and C. Our present work used fluorescent fusion proteins to determine the cellular localization of the Amts and tested the hypothesis that the transporters mediate removal of ammonia generated endogenously from the elevated protein catabolism common to many protists. Results Using RFP and YFP fusion constructs driven by the actin 15 promoter, we found that the three ammonium transporters were localized on the plasma membrane and on the membranes of subcellular organelles. AmtA and AmtB were localized on the membranes of endolysosomes and phagosomes, with AmtB further localized on the membranes of contractile vacuoles. AmtC also was localized on subcellular organelles when it was stabilized by coexpression with either the AmtA or AmtB fusion transporter. The three ammonium transporters exported ammonia linearly with regard to time during the first 18 hours of the developmental program as revealed by reduced export in the null strains. The fluorescently tagged transporters rescued export when expressed in the null strains, and thus they were functional transporters. Conclusion Unlike ammonium transporters in most organisms, which import NH3/NH4+ as a nitrogen source, those of Dictyostelium export ammonia/ammonium as a waste product from extensive catabolism of exogenously derived and endogenous proteins. Localization on proteolytic organelles and on the neutral contractile vacuole suggests that Dictyostelium ammonium transporters may have unique subcellular functions and play a role in the maintenance of intracellular ammonium distribution. A lack of correlation between the null strain phenotypes and ammonia excretion properties of the ammonium transporters suggests that it is not
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Improved Spectra for MALDI MSI of Peptides Using Ammonium Phosphate Monobasic in MALDI Matrix.
Ucal, Yasemin; Ozpinar, Aysel
2018-05-10
MALDI mass spectrometry imaging (MSI) enables analysis of peptides along with histology. However, there are several critical steps in MALDI MSI of peptides, one of which is spectral quality. Suppression of MALDI matrix clusters by the aid of ammonium salts in MALDI experiments is well-known. It is asserted that addition of ammonium salts dissociates potential matrix adducts and thereafter decreases matrix cluster formation. Consequently, MALDI MS sensitivity and mass accuracy increases. Up to our knowledge, a limited number of MALDI MSI studies used ammonium salts as matrix additives to suppress matrix clusters and enhance peptide signals. In this work, we investigated the effect of ammonium phosphate monobasic (AmP) as alpha-cyano-4-hydroxycinnamic acid (α-CHCA) matrix additive in MALDI MSI of peptides. Prior to MALDI MSI, the effect of varying concentrations of AmP in α-CHCA were assessed in bovine serum albumin (BSA) tryptic digests and compared with the control (α-CHCA without AmP). Based on our data, the addition of AmP as matrix additive decreased matrix cluster formation regardless of its concentration and, specifically 8 mM AmP and 10 mM AmP increased BSA peptide signal intensities. In MALDI MSI of peptides, both 8 mM, and 10 mM AmP in α-CHCA improved peptide signals especially in the mass range of m/z 2000 to 3000. In particular, 9 peptide signals were found to have differential intensities within the tissues deposited with AmP in α-CHCA (AUC>0.60). To the best of our knowledge, this is the first MALDI MSI of peptides work investigating different concentrations of AmP as α-CHCA matrix additive in order to enhance peptide signals in formalin fixed paraffin embedded (FFPE) tissues. Further, AmP as part of α-CHCA matrix could enhance protein identifications and support MALDI MSI based proteomic approaches. This article is protected by copyright. All rights reserved.
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Abiotic stresses affect Trichoderma harzianum T39-induced resistance to downy mildew in grapevine.
Roatti, Benedetta; Perazzolli, Michele; Gessler, Cesare; Pertot, Ilaria
2013-12-01
Enhancement of plant defense through the application of resistance inducers seems a promising alternative to chemical fungicides for controlling crop diseases but the efficacy can be affected by abiotic factors in the field. Plants respond to abiotic stresses with hormonal signals that may interfere with the mechanisms of induced systemic resistance (ISR) to pathogens. In this study, we exposed grapevines to heat, drought, or both to investigate the effects of abiotic stresses on grapevine resistance induced by Trichoderma harzianum T39 (T39) to downy mildew. Whereas the efficacy of T39-induced resistance was not affected by exposure to heat or drought, it was significantly reduced by combined abiotic stresses. Decrease of leaf water potential and upregulation of heat-stress markers confirmed that plants reacted to abiotic stresses. Basal expression of defense-related genes and their upregulation during T39-induced resistance were attenuated by abiotic stresses, in agreement with the reduced efficacy of T39. The evidence reported here suggests that exposure of crops to abiotic stress should be carefully considered to optimize the use of resistance inducers, especially in view of future global climate changes. Expression analysis of ISR marker genes could be helpful to identify when plants are responding to abiotic stresses, in order to optimize treatments with resistance inducers in field.
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International Nuclear Information System (INIS)
Aronson, F.L.; Hwang, L.L.Y.; Ronca, N.; Solomon, N.A.; Steigman, J.
1985-01-01
Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl 4 - , which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO 4 - by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were formed and stabilized in dilute acid containing quaternary ammonium salts. Their UV spectra showed the well-resolved vibronic fine structure associated with the symmetric chromium-to-oxygen charge-transfer band. It is known that these progressions are resolved in aprotic solvents, but not in aqueous acidic solution alone, and that the loss of fine structure in aqueous media is due to hydrogen bonding. The stabilization of anionic metal complexes and the resolution of vibronic structure in halochromates are probably consequences of water-structure-enforced ion paring. The present work suggests that the water molecules in immediate contact with the complex anions are more strongly hydrogen bonded to each other than to the complex. 21 references, 4 figures
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Ammonium release from a blanket peatland into headwater stream systems
International Nuclear Information System (INIS)
Daniels, S.M.; Evans, M.G.; Agnew, C.T.; Allott, T.E.H.
2012-01-01
Hydrochemical sampling of South Pennine (UK) headwater streams draining eroded upland peatlands demonstrates these systems are nitrogen saturated, with significant leaching of dissolved inorganic nitrogen (DIN), particularly ammonium, during both stormflow and baseflow conditions. DIN leaching at sub-catchment scale is controlled by geomorphological context; in catchments with low gully densities ammonium leaching dominates whereas highly gullied catchments leach ammonium and nitrate since lower water tables and increased aeration encourages nitrification. Stormflow flux calculations indicate that: approximately equivalent amounts of nitrate are deposited and exported; ammonium export significantly exceeds atmospheric inputs. This suggests two ammonium sources: high atmospheric loadings; and mineralisation of organic nitrogen stored in peat. Downstream trends indicate rapid transformation of leached ammonium into nitrate. It is important that low-order headwater streams are adequately considered when assessing impacts of atmospheric loads on the hydrochemistry of stream networks, especially with respect to erosion, climate change and reduced precipitation. - Highlights: ► Headwaters draining eroded South Pennine (UK) peatlands are nitrogen saturated. ► Ammonium and nitrate leaching arises from aeration due to lower water tables. ► Nitrate deposition equals export during storms; ammonium export exceeds input. ► Ammonia input from high atmospheric loading and mineralisation of organic nitrogen. ► Downstream nitrogen trends indicate rapid transformation of ammonium into nitrate. - Inorganic nitrogen leaching from South Pennine peatlands is dominated by ammonium that is rapidly transformed within-streams to nitrate.
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Improving abiotic stress tolerance of quinoa
DEFF Research Database (Denmark)
Yang, Aizheng
Global food security faces the challenges of rapid population growth and shortage of water resources. Drought, heat waves and soil salinity are becoming more frequent and extreme due to climatic changes in many regions of the world, and resulting in yield reduction of many crops. It is hypothesized...... that quinoa has the potential to grow under a range of abiotic stresses, tolerating levels regarded as stresses in other crop species. Therefore cultivation of quinoa (Chenopodium quinoa Willd.) could be an alternative option in such regions. Even though quinoa is more tolerant to abiotic stress than most...... other crops, its productivity declines under severe drought, high salt conditions and harsh climate conditions. Different management approaches including water-saving irrigation methods (such as deficit irrigation, DI and alternate root-zone drying irrigation, ARD), inoculating crop seeds with plant...
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International Nuclear Information System (INIS)
Rofail, N.H.; ELfekey, S.A.
1992-01-01
Ammonium uranates (AU) were precipitated from a nuclear-pure uranyl nitrate solution using different precipitating agents. IR spectra of the obtained uranates and oxides formed during their thermal decomposition have been studied. The results indicated that the precipitating agent, mode of stirring, washing and calcining temperature are important factors for a specific oxide formation.4 FIG., 3 TAB
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Exploring biotic vs. abiotic controls on syngenetic carbonate and clay mineral precipitation
Nascimento, Gabriela S.; McKenzie, Judith A.; Martinez Ruiz, Francisca; Bontognali, Tomaso R. R.; Vasconcelos, Crisogono
2016-04-01
A possible syngenetic relationship between carbonate and clay mineral precipitation has been reported for sedimentary rocks deposited in both lacustrine and marine sedimentary environments throughout the geological record. In particular, the mineral dolomite is often found associated with Mg-rich clays, such as stevensite. It is notable that this carbonate/clay association has been recorded in numerous samples taken from modern dolomite precipitating environments; for example, the Coorong lakes, South Australia, coastal sabkhas, Abu Dhabi, UAE and coastal hypersaline lagoons (Lagoa Vermelha and Brejo do Espinho) east of Rio de Janeiro, Brazil. An HRTEM study of samples from these three locations indicates a possible physical/chemical association between the Ca-dolomite and Mg-rich clays, demonstrating a probable co-precipitation. To test this hypothesis, we have conducted a series of biotic and abiotic laboratory experiments. If this syngenesis actually occurs in nature, what, if any, are the biogeochemical processes controlling these precipitation reactions? Our experiments were designed to determine the extent of the biotic versus abiotic component influencing the mineral precipitation and, in the case of a biotic influence, to understand the mechanism through which microorganisms might mediate the formation of clay minerals. The experiments were carried out in the Geomicrobiology Laboratory of ETH Zürich using cultures of living microbes and artificial organic compounds that simulate functional groups present in natural biofilms formed under both aerobic and anaerobic conditions. In addition, pure inorganic experiments were designed to understand possible physico-chemical conditions for diagenetic processes that could induce dissolution of Mg-carbonates and precipitation of Mg-rich clays. Our results show a remarkable biotic influence during the formation of clay minerals. Specifically, extracellular polymeric substances (EPS), released by microbes in their
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Orsinger-Jacobsen, Samantha J; Patel, Shenan S; Vellozzi, Ernestine M; Gialanella, Phillip; Nimrichter, Leonardo; Miranda, Kildare; Martinez, Luis R
2013-12-01
Acinetobacter baumannii is a frequent cause of hospital-acquired pneumonia, and has recently increased in incidence as the causative agent of severe disease in troops wounded in Afghanistan and Iraq. Clinical approaches are limited since A. baumannii strains isolated from patients are extremely resistant to current antimicrobials. A. baumannii can survive desiccation and during outbreaks has been recovered from various sites in the patients' environment. To better understand its prevalence in hospital settings, we used a stainless steel washer (SSW) platform to investigate A. baumannii biofilm formation on abiotic surfaces. Scanning electron microscopy demonstrated that A. baumannii forms strong biofilms on stainless steel surfaces. This platform was combined with a colorimetric 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay to observe the metabolic activity of bacterial cells, and to facilitate the manipulation and comparison of multiple A. baumannii clinical strains. A strong correlation between XTT and c.f.u. assays was demonstrated. To complement the cell viability assays, A. baumannii biofilm mass was measured by crystal violet staining. Furthermore, the effect of commonly used disinfectants and environmental stressors on A. baumannii biofilms and planktonic cells was compared and characterized. Biofilms on SSWs were significantly more resistant than their planktonic counterparts, providing additional evidence that may allow us to understand the high prevalence of this microbe in hospital settings. Our results validate that SSWs are a simple, versatile and innovative method to study A. baumannii biofilms in vitro.
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Liu, Xiaoxia; Yang, Jiqing; Sun, Shucheng; Guo, Liping; Yang, Li
2016-10-01
We present here an easy-to-operate and efficient method for enzyme and inhibition assays of urease, which is a widely distributed and important enzyme that catalyzes the hydrolysis of urea to ammonia and CO 2 . The assay was achieved by integrating CE technique and rapid on-line derivatization method, allowing us to continuously drive the sample to the capillary, thus to measure the amount of the product ammonia from the beginning to the end of the reaction. The method exhibits excellent repeatability with RSD as low as 2.5% for the initial reaction rate (n = 5), with the LOD of ammonia of 20 μM (S/N = 5). The enzyme activity as well as the inhibition of urease by Cu 2+ were investigated using the present method. The results show that Cu 2+ is a noncompetitive inhibitor on urease, in accordance with the result published in the literature. The enzyme activity and inhibition kinetic constants were obtained and were found to be consistent with the results of traditional off-line enzyme assays. Our study indicates that the present approach is a reliable and convenient method for analysis of the urease activity and inhibition kinetics by continuous on-line monitoring of the ammonium formation based on CE. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Mutagenicity of quaternary ammonium salts containing carbohydrate moieties
Energy Technology Data Exchange (ETDEWEB)
Dmochowska, Barbara [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Piosik, Jacek; Woziwodzka, Anna [Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk (Poland); Sikora, Karol; Wisniewski, Andrzej [Department of Carbohydrate Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Wegrzyn, Grzegorz, E-mail: wegrzyn@biotech.univ.gda.pl [Department of Molecular Biology, University of Gdansk, Kladki 24, 80-822 Gdansk (Poland)
2011-10-15
Highlights: {yields} A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. {yields} The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. {yields} The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. {yields} We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.
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Mutagenicity of quaternary ammonium salts containing carbohydrate moieties
International Nuclear Information System (INIS)
Dmochowska, Barbara; Piosik, Jacek; Woziwodzka, Anna; Sikora, Karol; Wisniewski, Andrzej; Wegrzyn, Grzegorz
2011-01-01
Highlights: → A series of quaternary ammonium salts containing carbohydrate moieties, with configuration D-galacto, D-gluco and D-manno, was synthesized and characterized. → The quaternary ammonium salts containing carbohydrate moieties revealed potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. → The N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. → We suggest that quaternary ammonium salts may be more hazardous than previously supposed. - Abstract: Quaternary ammonium salts are widely used in industrial, agricultural, healthcare and domestic applications. They are believed to be safe compounds, with little or no health hazard to humans. However, in this report, we demonstrate that a series of newly synthesized quaternary ammonium salts containing carbohydrate moieties reveal potent mutagenic activities, as assessed by using the Vibrio harveyi bioluminescence mutagenicity test. D-Gluco- and D-galacto-derivatives were found to have a higher mutagenic potential than D-manno-derivatives. Among the former groups of compounds, the N-[2-(D-glycopyranosyloxy)ethyl]-N,N,N-trimethylaminium salts were of the highest activity in the mutagenicity assay. These results suggest that the safety of quaternary ammonium salts may be lower than previously supposed, indicating a need for testing such compounds for their mutagenicity.
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Liu, Tengyu; Huang, Dan Dan; Li, Zijun; Liu, Qianyun; Chan, ManNin; Chan, Chak K.
2018-04-01
The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm-3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm-3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m / z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors
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Current perspectives in proteomic analysis of abiotic stress in Grapevines
Directory of Open Access Journals (Sweden)
Iniga Seraphina George
2014-12-01
Full Text Available Grapes are an important crop plant which forms the basis of a globally important industry. Grape and wine production is particularly vulnerable to environmental and climatic fluctuations, which makes it essential for us to develop a greater understanding of the molecular level responses of grape plants to various abiotic stresses. The completion of the initial grape genome sequence in 2007 has led to a significant increase in research on grapes using proteomics approaches. In this article, we discuss some of the current research on abiotic stress in grapevines, in the context of abiotic stress research in other plant species. We also highlight some of the current limitations in grapevine proteomics and identify areas with promising scope for potential future research.
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Ammonium inhibition of nitrogenase activity in Herbaspirillum seropedicae
Energy Technology Data Exchange (ETDEWEB)
Fu, H.; Burris, R.H. (Univ. of Wisconsin, Madison (USA))
1989-06-01
The effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated N{sub 2}-fixing bacterium Herbaspirillum seropedicae was investigated in comparison with Azospirillum spp. and Rhodospirillum rubrum. H. seropedicae is microaerophilic, and its optimal dissolved oxygen level is from 0.04 to 0.2 kPa for dinitrogen fixation but higher when it is supplied with fixed nitrogen. No nitrogenase activity was detected when the dissolved O{sub 2} level corresponded to 4.0 kPa. Ammonium, a product of the nitrogenase reaction, reversible inhibited nitrogenase activity when added to derepressed cell cultures. However, the inhibition of nitrogenase activity was only partial even with concentrations of ammonium chloride as high as 20 mM. Amides such as glutamine and asparagine partially inhibited nitrogenase activity, but glutamate did not. Nitrogenase in crude extracts prepared from ammonium-inhibited cells showed activity as high as in extracts from N{sub 2}-fixing cells. The pattern of the dinitrogenase and the dinitrogenase reductase revealed by the immunoblotting technique did not change upon ammonium chloride treatment of cells in vivo. No homologous sequences were detected with the draT-draG probe from Azospirillum lipoferum. There is no clear evidence that ADP-ribosylation of the dinitrogenase reductase is involved in the ammonium inhibition of H. seropedicae. The uncoupler carbonyl cyanide m-chlorophenylhydrazone decreased the intracellular ATP concentration and inhibited the nitrogenase activity of whole cells. The ATP pool was significantly disturbed when cultures were treated with ammonium in vivo.
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Quartz crystal microbalance sensor using ionophore for ammonium ion detection.
Kosaki, Yasuhiro; Takano, Kosuke; Citterio, Daniel; Suzuki, Koji; Shiratori, Seimei
2012-01-01
Ionophore-based quartz crystal microbalance (QCM) ammonium ion sensors with a detection limit for ammonium ion concentrations as low as 2.2 microM were fabricated. Ionophores are molecules, which selectively bind a particular ion. In this study, one of the known ionophores for ammonium, nonactin, was used to detect ammonium ions for environmental in-situ monitoring of aquarium water for the first time. To fabricate the sensing films, poly(vinyl chloride) was used as the matrix for the immobilization of nonactin. Furthermore, the anionic additive, tetrakis (4-chlorophenyl) borate potassium salt and the plasticizer dioctyl sebacate were used to enhance the sensor properties. The sensor allowed detecting ammonium ions not only in static solution, but also in flowing water. The sensor showed a nearly linear response with the increase of the ammonium ion concentration. The QCM resonance frequency increased with the increase of ammonium ion concentration, suggesting a decreasing weight of the sensing film. The detailed response mechanism could not be verified yet. However, from the results obtained when using a different plasticizer, nitrophenyl octyl ether, it is considered that this effect is caused by the release of water molecules. Consequently, the newly fabricated sensor detects ammonium ions by discharge of water. It shows high selectivity over potassium and sodium ions. We conclude that the newly fabricated sensor can be applied for detecting ammonium ions in aquarium water, since it allows measuring low ammonium ion concentrations. This sensor will be usable for water quality monitoring and controlling.
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Schindler, Yael; Michel, Christian; Holm, Patricia; Alewell, Christine
2010-05-01
The hyporheic zone can be characterized by multiple abiotic parameters (e.g. bulk density, texture, temperature, oxygen, ammonium, nitrate) which are all influenced directly or indirectly by the exchange processes between surface water and groundwater. These processes can vary both in time and space and are mainly driven by river discharge, ground water level and flow patterns. The input of fine sediment particles can change water-riverbed interactions through river bed clogging potentially affecting the embryonal development and survival of gravel spawning fish, such as brown trout (Salmo trutta L.). With our investigations we aim to understand these complex interactions spatially and temporally on a relevant small scale, i.e. within individual artificial brown trout redds. We designed an experimental field setup to directly investigate i) the influence of the abiotic river and redd environment on brown trout embryo development and ii) the hydrological dynamics affecting the abiotic environment in artificial brown trout. Additionally, our setup allows investigating the temporal dynamics of i) fine-sediment infiltration into the artificial redds and ii) embryo survival to two distinct developmental stages (i.e. eyed stage and hatch) The experiment was conducted in three sites of a typical Swiss river (Enziwigger, Canton of Luzern) with a strongly modified morphology. Individual sites represented a high, medium and low fine-sediment load. In each site, six artificial redds (18 in total) were built and data were collected during the entire incubation phase. Redds were located in places where natural spawning of brown trout is present. We adapted multiple established methods to the smaller scale of our river to study the dynamics of the most relevant abiotic parameters potentially affecting embryo development: Oxygen content and temperature was monitored continuously in different depths, fine sediment (bedload, suspended sediment load and its input in the river bed
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Properties and thermal decomposition of the double salts of uranyl nitrate-ammonium nitrate
International Nuclear Information System (INIS)
Notz, K.J.; Haas, R.A.
1989-01-01
The formation of ammonium nitrate-uranyl nitrate double salts has important effects on the thermal denitration process for the preparation of UO 3 and on the physical properties of the resulting product. Analyses were performed, and properties and decomposition behavior were determined for three double salts: NH 4 UO 2 (NO 3 ) 3 , (NH 4 ) 2 UO 2 (NO 3 ) 4 , and (NH 4 ) 2 UO 2 (NO 3 ) 4 ·2H 2 O. The tinitrate salt decomposes without melting at 270-300 C to give a γ-UO 3 powder of ∼3-μm average size, with good ceramic properties for fabrication into UO 2 nuclear fuel pellets. The tetranitrate dihydrate melts at 48 C; it also dehydrates to the anhydrous salt. The anhydrous tetranitrate decomposes exothermically, without melting, at 170-270 C by losing one mole of ammonium nitrate to form the trinitrate salt
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Can plant-natural enemy communication withstand disruption by biotic and abiotic factors?
Clavijo McCormick, Andrea
2016-12-01
The attraction of natural enemies towards herbivore-induced plant volatiles is a well-documented phenomenon. However, the majority of published studies are carried under optimal water and nutrient regimes and with just one herbivore. But what happens when additional levels of ecological complexity are added? Does the presence of a second herbivore, microorganisms, and abiotic stress interfere with plant-natural enemy communication? or is communication stable enough to withstand disruption by additional biotic and abiotic factors?Investigating the effects of these additional levels of ecological complexity is key to understanding the stability of tritrophic interactions in natural ecosystems and may aid to forecast the impact of environmental disturbances on these, especially in climate change scenarios, which are often associated with modifications in plant and arthropod species distribution and increased levels of abiotic stress.This review explores the literature on natural enemy attraction to herbivore-induced volatiles when, besides herbivory, plants are challenged by additional biotic and abiotic factors.The aim of this review was to establish the impact of different biotic and abiotic factors on plant-natural enemy communication and to highlight critical aspects to guide future research efforts.
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Oxidation of ammonium sulfite in aqueous solutions using ozone technology
Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan
2013-03-01
How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.
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Assimilation of ammonium and nitrate nitrogen by bean plants
International Nuclear Information System (INIS)
Volk, R.J.; Chaillou, S.; Morot-Gaudry, J.F.; Mariotti, A.
1989-01-01
Enhanced growth is often observed in plants growing on combined ammonium and nitrate nutrition. The physiological basis for such enhancement was examined by exposing non-nodulated bean (Phaseolus vulgaris L.) plants to 15 N-labeled, 1.0 mM N solutions containing 0, 33, 67 or 100% of the N as ammonium, the balance being nitrate. Maximal total N uptake and biomass production were attained by plants receiving 33% ammonium. A higher proportion of incoming ammonium than nitrate was incorporated into root protein. This was accompanied by increased partitioning of plant biomass to roots. It was concluded that as a consequence of greater N metabolism in the root under mixed ammonium and nitrate nutrition, the root became a more active sink for photosynthate. Concurrently, the augmented supply of N to the shoot enhanced net photosynthesis as reflected in increased plant biomass
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Thermal analysis studies of ammonium uranyl carbonate
International Nuclear Information System (INIS)
Cao Xinsheng; Ma Xuezhong; Wang Fapin; Liu Naixin; Ji Changhong
1988-01-01
The simultaneous thermogravimetry and differential thermal analysis of the ammonium uranyl carbonate powder were performed with heat balance in the following atmosphers: Air, Ar and Ar-8%H 2 . The thermogravimetry and differential thermal analysis curves of the ammonium uranyl carbonate powder obtained from different source were reported and discussed
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Biotic and abiotic variables show little redundancy in explaining tree species distributions
DEFF Research Database (Denmark)
Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.
2010-01-01
Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...
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Energy Technology Data Exchange (ETDEWEB)
Lee, Se Hun [Department of Convergence Nanoscience, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Koo, Jun Mo [Department of Organic and Nano Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Oh, Seong Geun, E-mail: seongoh@hanyang.ac.kr [Department of Chemical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Im, Seung Soon, E-mail: imss007@hanyang.ac.kr [Department of Convergence Nanoscience, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Department of Organic and Nano Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of)
2017-06-15
Ammonium vanadate nanofibers were synthesized by simple reflux method in aqueous V{sub 2}O{sub 5} solution with ammonium persulfate without relying on surfactants, catalysts, harmful solvents and autoclave. The degree of intercalation by cationic ammonium ions into the crystal structure of vanadium oxide along with its change in chemical composition were analyzed by thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR). The morphological changes toward nanofiber structure, having diameter of 20–30 nm and a few μm length, were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influences of synthetic conditions, such as reaction time and concentration of sulfate (SO{sub 4}{sup 2-}), on the crystal structures and morphologies of the resulting products have investigated. As a result, the ammonium vanadate nanofiber was formed in a short reaction time through a simple reflux method and yielded comparable electrical conductivity 1.47 × 10{sup -2} S/cm. - Highlights: • Ammonium vanadate nanofiber (AVFr) was prepared by simple reflux method. • AVFr yielded comparable electrical conductivity 1.47 × 10{sup -2} S/cm. • The electrical conductivity was improved by the increased amount of ammonium ion. • Sulfate ions (SO{sub 4}{sup 2-}) play a crucial role in controlling the morphology of nanofiber.
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Turbulence and Cavitation Suppression by Quaternary Ammonium Salt Additives.
Naseri, Homa; Trickett, Kieran; Mitroglou, Nicholas; Karathanassis, Ioannis; Koukouvinis, Phoevos; Gavaises, Manolis; Barbour, Robert; Diamond, Dale; Rogers, Sarah E; Santini, Maurizio; Wang, Jin
2018-05-16
We identify the physical mechanism through which newly developed quaternary ammonium salt (QAS) deposit control additives (DCAs) affect the rheological properties of cavitating turbulent flows, resulting in an increase in the volumetric efficiency of clean injectors fuelled with diesel or biodiesel fuels. Quaternary ammonium surfactants with appropriate counterions can be very effective in reducing the turbulent drag in aqueous solutions, however, less is known about the effect of such surfactants in oil-based solvents or in cavitating flow conditions. Small-angle neutron scattering (SANS) investigations show that in traditional DCA fuel compositions only reverse spherical micelles form, whereas reverse cylindrical micelles are detected by blending the fuel with the QAS additive. Moreover, experiments utilising X-ray micro computed tomography (micro-CT) in nozzle replicas, quantify that in cavitation regions the liquid fraction is increased in the presence of the QAS additive. Furthermore, high-flux X-ray phase contrast imaging (XPCI) measurements identify a flow stabilization effect in the region of vortex cavitation by the QAS additive. The effect of the formation of cylindrical micelles is reproduced with computational fluid dynamics (CFD) simulations by including viscoelastic characteristics for the flow. It is demonstrated that viscoelasticity can reduce turbulence and suppress cavitation, and subsequently increase the injector's volumetric efficiency.
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Chemical effects induced by γ-irradiated ammonium chloride in aqueous medium
International Nuclear Information System (INIS)
Ravishankar, D.; Chabria, N.
1989-01-01
Dissolution of γ-irradiated ammonium chloride in aqueous solutions of nitrate and iodide results in the formation of NO 2 - and I 2 as products. Appropriate mechanisms are suggested in the light of known stable radiolytic products formed in the salt during irradiation. The variation in the yields of products in the solution with the variation in γ-dose, amount, particle size is studied. The effect of thermal annealing on the yields of products is explained on the basis of annealing of radiolytic products. (author) 13 refs.; 4 figs
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Effect of abiotic stress under light and dark conditions on carotenoid ...
African Journals Online (AJOL)
The aim of this study was to observe the effect of abiotic stress under light and dark conditions on pumpkin calluses carotenoid. Plant elicitors used to create abiotic stress in this study were Polyethylene Glycol 4000 for drought stress, Jasmonic Acid and Salicylic Acid for hormones stress and Murashige and Skoog Salt for ...
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Ammonium-induced calcium mobilization in 1321N1 astrocytoma cells
International Nuclear Information System (INIS)
Hillmann, Petra; Koese, Meryem; Soehl, Kristina; Mueller, Christa E.
2008-01-01
High blood levels of ammonium/ammonia (NH 4 + /NH 3 ) are associated with severe neurotoxicity as observed in hepatic encephalopathy (HE). Astrocytes are the main targets of ammonium toxicity, while neuronal cells are less vulnerable. In the present study, an astrocytoma cell line 1321N1 and a neuroblastoma glioma hybrid cell line NG108-15 were used as model systems for astrocytes and neuronal cells, respectively. Ammonium salts evoked a transient increase in intracellular calcium concentrations ([Ca 2+ ] i ) in astrocytoma (EC 50 = 6.38 mM), but not in NG108-15 cells. The ammonium-induced increase in [Ca 2+ ] i was due to an intracellular effect of NH 4 + /NH 3 and was independent of extracellular calcium. Acetate completely inhibited the ammonium effect. Ammonium potently reduced calcium signaling by G q protein-coupled receptors (H 1 and M3) expressed on the cells. Ammonium (5 mM) also significantly inhibited the proliferation of 1321N1 astrocytoma cells. While mRNA for the mammalian ammonium transporters RhBG and RhCG could not be detected in 1321N1 astrocytoma cells, both transporters were expressed in NG108-15 cells. RhBG and RhBC in brain may promote the excretion of NH 3 /NH 4 + from neuronal cells. Cellular uptake of NH 4 + /NH 3 was mainly by passive diffusion of NH 3 . Human 1321N1 astrocytoma cells appear to be an excellent, easily accessible human model for studying HE, which can substitute animal studies, while NG108-15 cells may be useful for investigating the role of the recently discovered Rhesus family type ammonium transporters in neuronal cells. Our findings may contribute to the understanding of pathologic ammonium effects in different brain cells, and to the treatment of hyperammonemia
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Chicken Juice Enhances Surface Attachment and Biofilm Formation of Campylobacter jejuni
Brown, Helen L.; Reuter, Mark; Salt, Louise J.; Cross, Kathryn L.; Betts, Roy P.
2014-01-01
The bacterial pathogen Campylobacter jejuni is primarily transmitted via the consumption of contaminated foodstuffs, especially poultry meat. In food processing environments, C. jejuni is required to survive a multitude of stresses and requires the use of specific survival mechanisms, such as biofilms. An initial step in biofilm formation is bacterial attachment to a surface. Here, we investigated the effects of a chicken meat exudate (chicken juice) on C. jejuni surface attachment and biofilm formation. Supplementation of brucella broth with ≥5% chicken juice resulted in increased biofilm formation on glass, polystyrene, and stainless steel surfaces with four C. jejuni isolates and one C. coli isolate in both microaerobic and aerobic conditions. When incubated with chicken juice, C. jejuni was both able to grow and form biofilms in static cultures in aerobic conditions. Electron microscopy showed that C. jejuni cells were associated with chicken juice particulates attached to the abiotic surface rather than the surface itself. This suggests that chicken juice contributes to C. jejuni biofilm formation by covering and conditioning the abiotic surface and is a source of nutrients. Chicken juice was able to complement the reduction in biofilm formation of an aflagellated mutant of C. jejuni, indicating that chicken juice may support food chain transmission of isolates with lowered motility. We provide here a useful model for studying the interaction of C. jejuni biofilms in food chain-relevant conditions and also show a possible mechanism for C. jejuni cell attachment and biofilm initiation on abiotic surfaces within the food chain. PMID:25192991
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VARIATION IN THE SENSITIVITY OF WANDERING JEW PLANTS TO GLUFOSINATE AMMONIUM
Directory of Open Access Journals (Sweden)
IVANA PAULA FERRAZ SANTOS DE BRITO
2017-01-01
Full Text Available This study aimed to identify the response of wandering jew (Commelina benghalensis L. plants to different doses of glufosinate ammonium and the sensitivity of plants populations to the herbicide. Two studies were conducted, both in a greenhouse, and were repeated at different times. In the first study, two experiments were conducted to examine the dose-response curve using seven different doses of the glufosinate ammonium herbicide (0, 50, 100, 200, 400, 800, and 1600 g a.i. ha-1 with four replicates each. In the second study, which examined the range in sensitivity of wandering jew plants to glufosinate ammonium, 26 plants were sprayed with a dose of 200 g a.i. ha-1 herbicide. Visual assessments of percent injury and measurements of leaf tissue ammonium content were conducted. The use of untreated wandering jew control plants allowed for the correlation of glufosinate ammonium treatment with the ammonium concentrations in treated plant tissues; the ammonium concentration increased as a function of herbicide application, albeit not linearly with the dose. Ammonium content varied among individuals of the wandering jew plant population.
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DEFF Research Database (Denmark)
De Corte, Simon; Bechstein, Stefanie; Lokanathan, Arcot R.
2013-01-01
An increasing demand for catalytic Pd nanoparticles has motivated the search for sustainable production methods. An innovative approach uses bacterial cells as support material for synthesizing Pd nanoparticles by reduction of Pd(II) with e.g. hydrogen or formate. Nevertheless, drawbacks...... nanoparticles, and that abiotic surfaces could support the Pd particle synthesis as efficiently as bacteria. In this study, we explore the possibility of replacing bacteria with amine-functionalized materials, and we compare different functionalization strategies. Pd nanoparticles formed on the support...... on these surfaces was higher than for Pd particles formed on Shewanella oneidensis cells. Smaller Pd nanoparticles generally have better catalytic properties, and previous studies have shown that the particle size can be lowered by increasing the amount of support material used during Pd particle formation. However...
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PRN 88-2: Clustering of Quaternary Ammonium Compounds
This Notice announces that EPA has clustered the Quaternary Ammonium Compounds into four groups for the purpose of testing chemicals to build a database that will support continued registration of the entire family of quaternary ammonium compounds
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Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth
International Nuclear Information System (INIS)
Domagal-Goldman, Shawn D.; Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S.
2014-01-01
The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O 2 ) or ozone (O 3 ) simultaneous to methane (CH 4 ) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O 2 and O 3 production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O 2 and O 3 buildup, caused by fast chemical production of these gases. This results in detectable abiotic O 3 and CH 4 features in the UV-visible, but no detectable abiotic O 2 features. Thus, simultaneous detection of O 3 and CH 4 by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O 2 and O 3 is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.
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DEFF Research Database (Denmark)
Huber, B.; Riedel, K.; Hentzer, Morten
2001-01-01
Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, the isolation of random mini-Tn5 insertion mutants of B. cepacia H111 defective in biofilm formation on an abiotic surface is reported. It is demons......Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, the isolation of random mini-Tn5 insertion mutants of B. cepacia H111 defective in biofilm formation on an abiotic surface is reported...
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Abiotic racemization kinetics of amino acids in marine sediments
DEFF Research Database (Denmark)
Steen, Andrew; Jørgensen, Bo Barker; Lomstein, Bente Aagaard
2013-01-01
Enantiomeric ratios of amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic racemize abiotically. Based on a heating experiment, we report Arrhenius parameters...... between different amino acids or depths. These results can be used in conjunction with measurements of sediment age to predict the ratio of D:L amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial...
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Removal of ammonium from aqueous solutions using alkali-modified biochars
Directory of Open Access Journals (Sweden)
Zhigang Liu
2016-10-01
Full Text Available Biochars converted from agricultural residuals can effectively remove ammonium from water. This work further improved the sorption ability of biochars to aqueous ammonium through alkali modification. Three modified biochars were prepared from agricultural residuals pre-treated with NaOH solution through low-temperature (300 °C slow pyrolysis. The modified biochars effectively removed ammonium ions from water under various conditions with relatively fast adsorption kinetics (reached equilibrium within 10 h and extremely high adsorption capacity (>200 mg/g. The Langmuir maximum capacity of the three modified biochars were between 313.9 and 518.9 mg/g, higher than many other ammonium adsorbents. Although the sorption of ammonium onto the modified biochar was affected by pH and temperature, it was high under all of the tested conditions. Findings from this work indicated that alkali-modified biochars can be used as an alternative adsorbent for the removal of ammonium from wastewater.
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Influence of Nitrogen Source on NDMA Formation during Chlorination of Diuron
Chen, Wei-Hsiang; Young, Thomas M.
2009-01-01
N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite diuron dose. Formation of dichloramine seemed to fully explain enhanced NDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface and groundwater in nitrogen forms and concentrations and disinfection approaches, suggest strategies to reduce NDMA formation should vary with drinking water source. PMID:19457535
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Ginger-supplemented diet ameliorates ammonium nitrate-induced ...
African Journals Online (AJOL)
The present study was designed to evaluate the capacity of ginger to repair the oxidative stress induced by ammonium nitrate. 50 male rats were divided into 5 groups; they underwent an oral treatment of ammonium nitrate and/or ginger (N mg/kg body weight + G% in diet) during 30 days. Group I served as control (C); ...
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Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS
International Nuclear Information System (INIS)
Krawczyk-Baersch, Evelyn; Schmeide, Katja; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C.
2017-01-01
XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k 3 -weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption 1 E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O eq , U-O ax , and U-Fe are similar to those determined for abiotic ferrihydrite samples.
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Radiolysis of aqueous solutions of ammonium bicarbonate over a large dose range
International Nuclear Information System (INIS)
Draganic, Z.D.; Negron-Mendoza, A.; Vujosevic, S.I.; Navarro-Gonzales, R.; Albarran-Sanchez, M.G.
1991-01-01
Oxygen-free aqueous solutions of 0.05 mol dm -3 ammonium and sodium bicarbonate were studied after receiving various doses of 60 Co gammas (0.01-400 kGy) or 0.5-20 Gy pulses of 10 Mev electrons. Formate and oxalate were found to be the main radiolytic products, in addition to trace amounts of formaldehyde and an unidentified polymer. A large initial yield of formate in the γ-radiolysis, G(HCOO - ) = 2.2, is due to the reaction COO - + HCO 3 - ↔ HCOO - +CO 3 - . The efficiency of organic synthesis within the large dose range studied is low and is explained by efficient pathways leading to the reformation of bicarbonate, where the reaction COO - + CO 3 - is particularly significant. (author)
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National Aeronautics and Space Administration — We will develop, demonstrate, and optimize a front-end ammonium reactor (NHxR) for the fast, precise, and accurate measurement of gas-phase ammonia (NH3) and...
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Influence of Ammonium Salt and Fermentation pH on Acarbose ...
African Journals Online (AJOL)
Purpose: To investigate the effect of ammonium salts and fermentation pH on the biosynthesis of acarbose by Streptomyces M37. Methods: Different ammonium salts were added to the fermentation broth of Streptomyces M37 to explore their effects on acarbose production. The concentration and addition time of ammonium ...
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Process for fracturing underground formations
Energy Technology Data Exchange (ETDEWEB)
Kiel, O M
1974-01-25
This invention concerns a process for fracturing underground formations and has as one object the mixing of viscous compositions. Through a borehole, a fluid is injected into the formation. This fluid contains a complex prepared by the reaction of an aliphatic quaternary ammonium compound with a water-soluble compound chosen from monosaccharides, disaccharides, trisaccharides, polysaccharides, and synthetic hydroxylated polymers with long chains. These complexes are formed at temperatures between 20/sup 0/ and 205/sup 0/C. The process also includes production of formation fluid into the borehole.
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Investigation of electric discharge treatment of water for ammonium nitrogen removal
International Nuclear Information System (INIS)
Nazarenko, O.B.; Shubin, B.G.
2007-01-01
The possibility of water purification from ammonium nitrogen using pulsed electric discharge in water-air mixtures was investigated. The model solution of chlorous ammonium was used in experiments. The concentration of ions ammonium was about 300 mg/l. Achieved reduction of ammonium concentration was about 35%. In this paper the mechanism of this process is discussed. The ways to increasing efficiency of this method are proposed
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Abscisic Acid and Abiotic Stress Tolerance in Crop Plants
Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu
2016-01-01
Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044
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Ammonium and methylammonium transport in Rhodobacter sphaeroides
International Nuclear Information System (INIS)
Cordts, M.L.; Gibson, J.
1987-01-01
Rhodobacter spheroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH 4 + to washed, nitrogen-free cell suspensions was followed by linear uptake of NH 4 + from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH 4 + . Transport of NH 4 + was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH 4 + concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH 4 + -free cell suspensions, methylammonium ( 14 CH 3 NH 3 + ) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The 14 CN 3 NH 3 + pool was not affected by methionine sulfoximine. Unlike NH 4 + uptake, 14 CH 3 NH 3 + uptake in nitrogen-free cell suspensions was repressed by growth in NH 4 + . These results suggest that R. sphaeroides may produce an NH 4 + -specific transport system in addition to the NH 4 + / 14 CH 3 NH 3 + transporter. This second transporter is able to produce normal-size NH 4 + pools but has very little affinity for 14 CH 3 NH 3 + and is not repressed by growth in high concentrations of NH 4 +
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Study on Thorium Hidroxide and Ammonium Diuranate precipitation
International Nuclear Information System (INIS)
Damunir; Sukarsono, R; Busron-Masduki; Indra-Suryawan
1996-01-01
Thorium hydroxide and ammonium diuranate precipitation studied by the reaction of mixed thorium nitrate and uranyl nitrate using ammonium hydroxide. The purposes of this research was study of pH condition. U/Th ratio and NH 4 OH concentration on the precipitation. Mixed of thorium nitrate and uranyl nitrate 50 ml was reacted by excess ammonium hydroxide 2 - 10 M, pH 4-8, 40-80 o C of temperature and 5 - 100 % ratio of U/Th. The best of precipitation depend on thorium and uranium content on the precipitation. The experiment result for the best condition of precipitation was 25 % of ratio U/Th, pH 6 - 8, 60-80 o C of temperature, and 6 - 10 M concentration of ammonium hydroxide, was produced precipitate by 3,938 - 5,455 weight percent of mean concentration of U and 22,365-31,873 weight percent of mean concentration of Th
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Directory of Open Access Journals (Sweden)
T. Liu
2018-04-01
Full Text Available The formation of secondary organic aerosol (SOA has been widely studied in the presence of dry seed particles at low relative humidity (RH. At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm−3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm−3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m ∕ z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS, indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory
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The Role of Silicon under Biotic and Abiotic Stress Conditions
Directory of Open Access Journals (Sweden)
İlkay YAVAŞ
2017-06-01
Full Text Available Biotic and abiotic stress factors can adversely affect the agricultural productivity leading to physiological and biochemical damage to crops. Therefore, the most effective way is to increase the resistance to stresses. Silicon plays a ro le in reducing the effects of abiotic and biotic stresses (drought, salt stress, disease and insect stress etc. on plants. Silicon is accumulated in the cell walls and intercellular spaces and thus it has beneficial effects on disease infestations in especially small grains. The application of silicon may reduce the effects of environmental stresses on plants while making effective use of plant nutrients such as nitrogen and phosphorous. Also, silicon may reduce the toxic effects of heavy metals in soil. I t may protect the foliage and increase light uptake and reduce respiration. Therefore, in this review, we discussed the effects of silicon on abiotic and biotic stresses in especially field crops.
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Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS
Energy Technology Data Exchange (ETDEWEB)
Krawczyk-Baersch, Evelyn [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Molecular Structures
2017-06-01
XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k{sup 3}-weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption {sup 1}E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O{sub eq}, U-O{sub ax}, and U-Fe are similar to those determined for abiotic ferrihydrite samples.
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Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth
Energy Technology Data Exchange (ETDEWEB)
Domagal-Goldman, Shawn D. [Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S., E-mail: shawn.goldman@nasa.gov [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States)
2014-09-10
The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.
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Abiotic dechlorination in rock matrices impacted by long-term exposure to TCE.
Schaefer, Charles E; Towne, Rachael M; Lippincott, David R; Lacombe, Pierre J; Bishop, Michael E; Dong, Hailiang
2015-01-01
Field and laboratory tests were performed to evaluate the abiotic reaction of trichloroethene (TCE) in sedimentary rock matrices. Hydraulically conductive fractures, and the rock directly adjacent to the hydraulically conductive fractures, within a historically contaminated TCE bedrock aquifer were used as the basis for this study. These results were compared to previous work using rock that had not been exposed to TCE (Schaefer et al., 2013) to assess the impact of long-term TCE exposure on the abiotic dechlorination reaction, as the longevity of these reactions after long-term exposure to TCE was hitherto unknown. Results showed that potential abiotic TCE degradation products, including ethane, ethene, and acetylene, were present in the conductive fractures. Using minimally disturbed slices of rock core at and near the fracture faces, laboratory testing on the rocks confirmed that abiotic dechlorination reactions between the rock matrix and TCE were occurring. Abiotic daughter products measured in the laboratory under controlled conditions were consistent with those measured in the conductive fractures, except that propane also was observed as a daughter product. TCE degradation measured in the laboratory was well described by a first order rate constant through the 118-d study. Observed bulk first-order TCE degradation rate constants within the rock matrix were 1.3×10(-8) s(-1). These results clearly show that abiotic dechlorination of TCE is occurring within the rock matrix, despite decades of exposure to TCE. Furthermore, these observed rates of TCE dechlorination are expected to have a substantial impact on TCE migration and uptake/release from rock matrices. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Nitrogen fertility and abiotic stresses management in cotton crop: a review.
Khan, Aziz; Tan, Daniel Kean Yuen; Afridi, Muhammad Zahir; Luo, Honghai; Tung, Shahbaz Atta; Ajab, Mir; Fahad, Shah
2017-06-01
This review outlines nitrogen (N) responses in crop production and potential management decisions to ameliorate abiotic stresses for better crop production. N is a primary constituent of the nucleotides and proteins that are essential for life. Production and application of N fertilizers consume huge amounts of energy, and excess is detrimental to the environment. Therefore, increasing plant N use efficiency (NUE) is important for the development of sustainable agriculture. NUE has a key role in crop yield and can be enhanced by controlling loss of fertilizers by application of humic acid and natural polymers (hydrogels), having high water-holding capacity which can improve plant performance under field conditions. Abiotic stresses such as waterlogging, drought, heat, and salinity are the major limitations for successful crop production. Therefore, integrated management approaches such as addition of aminoethoxyvinylglycine (AVG), the film antitranspirant (di-1-p-menthene and pinolene) nutrients, hydrogels, and phytohormones may provide novel approaches to improve plant tolerance against abiotic stress-induced damage. Moreover, for plant breeders and molecular biologists, it is a challenge to develop cotton cultivars that can tolerate plant abiotic stresses while having high potential NUE for the future.
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WRKY proteins: signaling and regulation of expression during abiotic stress responses.
Banerjee, Aditya; Roychoudhury, Aryadeep
2015-01-01
WRKY proteins are emerging players in plant signaling and have been thoroughly reported to play important roles in plants under biotic stress like pathogen attack. However, recent advances in this field do reveal the enormous significance of these proteins in eliciting responses induced by abiotic stresses. WRKY proteins act as major transcription factors, either as positive or negative regulators. Specific WRKY factors which help in the expression of a cluster of stress-responsive genes are being targeted and genetically modified to induce improved abiotic stress tolerance in plants. The knowledge regarding the signaling cascade leading to the activation of the WRKY proteins, their interaction with other proteins of the signaling pathway, and the downstream genes activated by them are altogether vital for justified targeting of the WRKY genes. WRKY proteins have also been considered to generate tolerance against multiple abiotic stresses with possible roles in mediating a cross talk between abiotic and biotic stress responses. In this review, we have reckoned the diverse signaling pattern and biological functions of WRKY proteins throughout the plant kingdom along with the growing prospects in this field of research.
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Unraveling the role of fungal symbionts in plant abiotic stress tolerance
Singh, Lamabam Peter
2011-01-01
Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress and heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered. PMID:21512319
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Energy harvesting by implantable abiotically catalyzed glucose fuel cells
Kerzenmacher, S.; Ducrée, J.; Zengerle, R.; von Stetten, F.
Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the μW-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices.
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Wang, Chao; Liu, Sitong; Xu, Xiaochen; Zhao, Chuanqi; Yang, Fenglin; Wang, Dong
2017-05-01
The objective of this study was to investigate the influence of extracellular polymeric substance (EPS) on the coupling effects between ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing (anammox) bacteria for the completely autotrophic nitrogen removal over nitrite (CANON) biofilm formation in a moving bed biofilm reactor (MBBR). Analysis of the quantity of EPS and cyclic diguanylate (c-di-GMP) confirmed that the contents of polysaccharides and c-di-GMP were correlated in the AOB sludge, anammox sludge, and CANON biofilm. The anammox sludge secreted more EPS (especially polysaccharides) than AOB with a markedly higher c-di-GMP content, which could be used by the bacteria to regulate the synthesis of exopolysaccharides that are ultimately used as a fixation matrix, for the adhesion of biomass. Indeed, increased intracellular c-di-GMP concentrations in the anammox sludge enhanced the regulation of polysaccharides to promote the adhesion of AOB and formation of the CANON biofilm. Overall, the results of this study provide new comprehensive information regarding the coupling effects of AOB and anammox bacteria for the nitrogen removal process.
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Compartment specific importance of glutathione during abiotic and biotic stress
Directory of Open Access Journals (Sweden)
Bernd eZechmann
2014-10-01
Full Text Available The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species, redox signaling, the modulation of defense gene expression and important for the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state of plants through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, Tobacco Mosaic Virus. The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g. glutathione synthesis takes place in chloroplasts and the cytosol. Thus this review will reveal the compartment specific importance of glutathione during abiotic and biotic stress conditions.
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Ammonium ions determination with polypyrrole modified electrode
Directory of Open Access Journals (Sweden)
Luiz Henrique Dall´Antonia
2007-03-01
Full Text Available The present work relates the preparation of polypyrrole films (PPy deposited on surfaces of glass carbon, nickel and ITO (tin oxide doped with indium on PET plastic, in order to study the ammonium detection. The popypyrrole films were polymerized with dodecylbenzenesulfonate (DBSA on the electrodes, at + 0,70 V vs. Ag/AgCl, based on a solution containing the pyrrole monomer and the amphiphilic salt. Films deposited on glass carbon presented better performance. Cyclic voltammetries, between – 1,50 to + 0,5 V vs. Ag/AgCl, were repeated adding different concentrations of NH4Cl, in order to observe the behavior of the film as a possible detector of ions NH4+. The peak current for oxidation varies with the concentration of ammonium. A linear region can be observed in the band of 0 to 80 mM, with a sensibility (Sppy approximately similar to 4,2 mA mM-1 cm-2, showing the efficacy of the electrodes as sensors of ammonium ions. The amount of deposited polymer, controlled by the time of growth, does not influence on the sensor sensibility. The modified electrode was used to determine ammonium in grounded waters.
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Ammonium and hydroxylamine uptake and accumulation in Nitrosomonas
Schmidt, I.; Look, C.; Bock, E.; Jetten, M.S.M.
2004-01-01
Starved cells of Nitrosomonas europaea and further ammonia oxidizers were able to rapidly accumulate ammonium and hydroxylamine to an internal concentration of about 1 and 0.8 M, respectively. In kinetic studies, the uptake/accumulation rates for ammonium [3.1 mmol (g protein)(-1) min(-1)] and
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Sources et marché du sulfate d'ammonium Sources of and Market for Ammonium Sulfate
Loussouarn C.; Chauvel A.; Barthel Y.
2006-01-01
Engrais azoté le plus utilisé dans le monde jusqu'en 1970, le sulfate d'ammonium ne représente plus aujourd'hui que 4 % de la fertilisation azotée. Avec une teneur en azote de 21 % seulement, il a été peu à peu remplacé comme engrais universel par des produits plus concentrés, notamment l'urée et le nitrate d'ammonium. Obtenu pour plus de 40 % comme sous-produit dans la synthèse de monomères comme le caprolactame, l'acrylonitrile ou le méthacrylate de méthyle, et pour près de 10 % dans le tra...
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Ortiz-Montalvo, Diana L; Häkkinen, Silja A K; Schwier, Allison N; Lim, Yong B; McNeill, V Faye; Turpin, Barbara J
2014-01-01
Glyoxal is an important precursor to secondary organic aerosol (SOA) formed through aqueous chemistry in clouds, fogs, and wet aerosols, yet the gas-particle partitioning of the resulting mixture is not well understood. This work characterizes the volatility behavior of the glyoxal precursor/product mix formed after aqueous hydroxyl radical oxidation and droplet evaporation under cloud-relevant conditions for 10 min, thus aiding the prediction of SOA via this pathway (SOACld). This work uses kinetic modeling for droplet composition, droplet evaporation experiments and temperature-programmed desorption aerosol-chemical ionization mass spectrometer analysis of gas-particle partitioning. An effective vapor pressure (p'L,eff) of ∼10(-7) atm and an enthalpy of vaporization (ΔHvap,eff) of ∼70 kJ/mol were estimated for this mixture. These estimates are similar to those of oxalic acid, which is a major product. Addition of ammonium until the pH reached 7 (with ammonium hydroxide) reduced the p'L,eff to 80 kJ/mol, at least in part via the formation of ammonium oxalate. pH 7 samples behaved like ammonium oxalate, which has a vapor pressure of ∼10(-11) atm. We conclude that ammonium addition has a large effect on the gas-particle partitioning of the mixture, substantially enhancing the yield of SOACld from glyoxal.
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Influence of nitrogen source on NDMA formation during chlorination of diuron.
Chen, Wei-Hsiang; Young, Thomas M
2009-07-01
N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N'-(3,4-dichlorophenyl)-N,N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitriteNDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface water and groundwater in nitrogen forms and concentrations and disinfection approaches suggest strategies to reduce NDMA formation should vary with drinking water source.
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78 FR 32690 - Certain Ammonium Nitrate From Ukraine
2013-05-31
... From Ukraine Determination On the basis of the record \\1\\ developed in the subject five-year review... certain ammonium nitrate from Ukraine would be likely to lead to continuation or recurrence of material... Ammonium Nitrate from Ukraine: Investigation No. 731-TA-894 (Second Review). By order of the Commission...
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International Nuclear Information System (INIS)
Mian, Ishaq Ahmad; Riaz, Muhammad; Cresser, Malcolm S.
2009-01-01
The physico-chemical absorption characteristics of ammonium-N for 10 soils from 5 profiles in York, UK, show its high potential mobility in N deposition-impacted, unfertilized, permanent grassland soils. Substantial proportions of ammonium-N inputs were retained in the solution phase, indicating that ammonium translocation plays an important role in the N cycling in, and losses from, such soils. This conclusion was further supported by measuring the ammonium-N leaching from intact plant/soil microcosms. The ammonium-N absorption characteristics apparently varied with soil pH, depth and soil texture. It was concluded for the most acid soils especially that ammonium-N leached from litter horizons could be seriously limiting the capacity of underlying soils to retain ammonium. Contrary to common opinion, more attention therefore needs to be paid to ammonium leaching and its potential role in biogeochemical N cycling in semi-natural soil systems subject to atmospheric pollution. - Ammonium mobility is more important than previously thought in N-impacted, unfertilized grasslands
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Removal of uranium from ammonium nitrate solution by nanofiltration
Energy Technology Data Exchange (ETDEWEB)
Wang, Runci; Yuan, Zhongwei; Yan, Taihong; Zheng, Weifang [China Institute of Atomic Energy, Beijing (China). Dept. of Radiochemistry
2017-07-01
Two types of nanofiltration membranes were tested to remove uranium dissolved in ammonium nitrate solution, and the influence of operating parameters as transmembrane pressure, tangential velocity and feed temperature was investigated. Experimental results showed NF270 membrane can reject more than 96% uranium and allow most (90% min) ammonium nitrate solution passed by, and with a permeate flux of 60 L/(m{sup 2}.h). Nanofiltration seems to be a promising technology for the removal of uranium and recovery of ammonium nitrate simultaneously.
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Markovski, C.; Byrne, J. M.; Lalla, E.; Lozano-Gorrín, A. D.; Klingelhöfer, G.; Rull, F.; Kappler, A.; Hoffmann, T.; Schröder, C.
2017-11-01
Searching for biomarkers or signatures of microbial transformations of minerals is a critical aspect for determining how life evolved on Earth, and whether or not life may have existed in other planets, including Mars. In order to solve such questions, several missions to Mars have sought to determine the geochemistry and mineralogy on the Martian surface. This research includes the two miniaturized Mössbauer spectrometers (MIMOS II) on board the Mars Exploration Rovers Spirit and Opportunity, which have detected a variety of iron minerals on Mars, including magnetite (Fe2+Fe3+2O4) and goethite (α-FeO(OH)). On Earth, both minerals can derive from microbiological activity (e.g. through dissimilatory iron reduction of ferrihydrite by Fe(III)-reducing bacteria). Here we used a lab based MIMOS II to characterize the mineral products of biogenic transformations of ferrihydrite to magnetite by the Fe(III)-reducing bacteria Geobacter sulfurreducens. In combination with Raman spectroscopy and X-ray diffraction (XRD), we observed the formation of magnetite, goethite and siderite. We compared the material produced by biogenic transformations to abiotic samples in order to distinguish abiotic and biotic iron minerals by techniques that are or will be available onboard Martian based laboratories. The results showed the possibility to distinguish the abiotic and biotic origin of the minerals. Mossbauer was able to distinguish the biotic/abiotic magnetite with the interpretation of the geological context (Fe content mineral assemblages and accompanying minerals) and the estimation of the particle size in a non-destructive way. The Raman was able to confirm the biotic/abiotic principal peaks of the magnetite, as well as the organic principal vibration bands attributed to the bacteria. Finally, the XRD confirmed the particle size and mineralogy.
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Energy Technology Data Exchange (ETDEWEB)
Kohga, Makoto; Nishino, Saeko [Department of Applied Chemistry, National Defense Academy, Yokosuka, Kanagawa 239-8686 (Japan)
2009-08-15
Ammonium nitrate (AN)-based composite propellants have attracted much attention, primarily because of the clean burning nature of AN as an oxidizer. However, such propellants have some disadvantages such as poor ignition and low burning rate. Ammonium dichromate (ADC) is used as a burning catalyst for AN-based propellants; however, the effect of ADC on the burning characteristics has yet to be sufficiently delineated. The burning characteristics of AN/ADC propellants prepared with various contents of AN and ADC have been investigated in this study. The theoretical performance of an AN-based propellant is improved by the addition of ADC. The increase in the burning rate is enhanced and the pressure deflagration limit (PDL) becomes lower with increasing amount of ADC added. The increasing ratio of the burning rate with respect to the amount of ADC is independent of the AN content and the combustion pressure. The optimal amount of ADC for improving the burning characteristics has been determined. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
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Energy Technology Data Exchange (ETDEWEB)
Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.
2009-04-01
The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.
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Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew
2014-06-01
We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.
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Titania may produce abiotic oxygen atmospheres on habitable exoplanets.
Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko
2015-09-10
The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.
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Oxygen dependency of neutrophilic Fe(II) oxidation by Leptothrix differs from abiotic reaction
Vollrath, S.; Behrends, T.; Van Cappellen, P.
2012-01-01
Neutrophilic Fe(II) oxidizing microorganisms are found in many natural environments. It has been hypothesized that, at low oxygen concentrations, microbial iron oxidation is favored over abiotic oxidation. Here, we compare the kinetics of abiotic Fe(II) oxidation to oxidation in the presence of
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A Role for the Mannose-Sensitive Hemagglutinin in Biofilm Formation by Vibrio cholerae El Tor
Watnick, Paula I.; Fullner, Karla Jean; Kolter, Roberto
1999-01-01
While much has been learned regarding the genetic basis of host-pathogen interactions, less is known about the molecular basis of a pathogen’s survival in the environment. Biofilm formation on abiotic surfaces represents a survival strategy utilized by many microbes. Here it is shown that Vibrio cholerae El Tor does not use the virulence-associated toxin-coregulated pilus to form biofilms on borosilicate but rather uses the mannose-sensitive hemagglutinin (MSHA) pilus, which plays no role in pathogenicity. In contrast, attachment of V. cholerae to chitin is shown to be independent of the MSHA pilus, suggesting divergent pathways for biofilm formation on nutritive and nonnutritive abiotic surfaces. PMID:10348878
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Modificated ammonium nitrate based on its melt and bentonic clay
TURDIALIEV UMID MUHTARALIEVICH; NAMAZOV SHAFOAT SATTAROVICH; REYMOV AHMED MAMBETKARIMOVICH; BEGLOV BORIS MIHAYLOVICH; MIRSALIMOVA SAODAT RAHMATJANOVNA
2016-01-01
The approaches of nonexplosive ammonium nitrate by mean introduction of different inorganic matter into ammonium nitrate’s composition have been analyzed in the study. The results of thermostable ammonium nitrate obtain using Azkamarsk, Lagonsk, Kattakurgansk, and Navbahorsk bentonite from Uzbekistan as an additive, have been given. Composition and property (granule strength, modification transition temperature, thermal effect of modification transition, dimensions of granule’s micropores and...
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Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress
AlShareef, Sahar A.
2017-06-01
Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.
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Cell Wall Metabolism in Response to Abiotic Stress
Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine
2015-01-01
This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320
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Ammonium Transformation in 14 Lakes along a Trophic Gradient
Directory of Open Access Journals (Sweden)
Barbara Leoni
2018-03-01
Full Text Available Ammonia is a widespread pollutant in aquatic ecosystems originating directly and indirectly from human activities, which can strongly affect the structure and functioning of the aquatic foodweb. The biological oxidation of NH4+ to nitrite, and then nitrate is a key part of the complex nitrogen cycle and a fundamental process in aquatic environments, having a profound influence on ecosystem stability and functionality. Environmental studies have shown that our current knowledge of physical and chemical factors that control this process and the abundance and function of involved microorganisms are not entirely understood. In this paper, the efficiency and the transformation velocity of ammonium into oxidised compounds in 14 south-alpine lakes in northern Italy, with a similar origin, but different trophic levels, are compared with lab-scale experimentations (20 °C, dark, oxygen saturation that are performed in artificial microcosms (4 L. The water samples were collected in different months to highlight the possible effect of seasonality on the development of the ammonium oxidation process. In four-liter microcosms, concentrations were increased by 1 mg/L NH4+ and the process of ammonium oxidation was constantly monitored. The time elapsed for the decrease of 25% and 95% of the initial ion ammonium concentration and the rate for that ammonium oxidation were evaluated. Principal Component Analysis and General Linear Model, performed on 56 observations and several chemical and physical parameters, highlighted the important roles of total phosphorus and nitrogen concentrations on the commencement of the oxidation process. Meanwhile, the natural concentration of ammonium influenced the rate of nitrification (µg NH4+/L day. Seasonality did not seem to significantly affect the ammonium transformation. The results highlight the different vulnerabilities of lakes with different trophic statuses.
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Ammonium in Witwatersrand reefs: a possible indicator of metamorphic fluid flow
International Nuclear Information System (INIS)
Meyer, F.M.
1991-01-01
Ammonium concentrations and NH 4 + /K ratios in the Kimberley Reef indicate chemical interaction with metamorphic fluids. The data, although preliminary, also suggests a gold-ammonium association in that higher gold levels are related to higher NH 4 + /K ratios. Samples from the Ventersdorp Contact Reef are also hydrothermally altered but no ammonium was detected. The low ammonium concentrations suggest that over-printing by NH 4 -bearing metamorphic fluids was negligible. From this it is concluded that chemically different fluid systems must have been operative, probably at different times, during Witwatersrand history. It appears, therefore, that ammonium geochemistry is potentially useful in the study of fluid flow and related gold (re)distribution in Witwatersrand reefs. 17 refs., 2 figs., 1 tab
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Jia, Huijun; Yuan, Qiuyan
2018-04-01
In this study, the effects of ammonium nitrogen concentration, algae biomass concentration, and light conditions (wavelength and intensity) on the ammonium removal efficiency of algae-bacteria consortia from wastewater were investigated. The results indicated that ammonium concentration and light intensity had a significant impact on nitrification. It was found that the highest ammonia concentration (430 mg N/L) in the influent resulted in the highest ammonia removal rate of 108 ± 3.6 mg N/L/days, which was two times higher than the influent with low ammonia concentration (40 mg N/L). At the lowest light intensity of 1000 Lux, algae biomass concentration, light wavelength, and light cycle did not show a significant effect on the performance of algal-bacterial consortium. Furthermore, the ammonia removal rate was approximately 83 ± 1.0 mg N/L/days, which was up to 40% faster than at the light intensity of 2500 Lux. It was concluded that the algae-bacteria consortia can effectively remove nitrogen from wastewater and the removal performance can be stabilized and enhanced using the low light intensity of 1000 Lux that is also a cost-effective strategy.
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Ji, Weihang; Koepsel, Richard R; Murata, Hironobu; Zadan, Sawyer; Campbell, Alan S; Russell, Alan J
2017-08-14
Antibacterial polymers are potentially powerful biocides that can destroy bacteria on contact. Debate in the literature has surrounded the mechanism of action of polymeric biocides and the propensity for bacteria to develop resistance to them. There has been particular interest in whether surfaces with covalently coupled polymeric biocides have the same mechanism of action and resistance profile as similar soluble polymeric biocides. We designed and synthesized a series of poly(quaternary ammonium) polymers, with tailorable molecular structures and architectures, to engineer their antibacterial specificity and their ability to delay the development of bacterial resistance. These linear poly(quaternary ammonium) homopolymers and block copolymers, generated using atom transfer radical polymerization, had structure-dependent antibacterial specificity toward Gram positive and negative bacterial species. When single block copolymers contained two polymer segments of differing antibacterial specificity, the polymer combined the specificities of its two components. Nanoparticulate human serum albumin-poly(quaternary ammonium) conjugates of these same polymers, synthesized via "grafting from" atom transfer radical polymerization, were strongly biocidal and also exhibited a marked decrease in the rate of bacterial resistance development relative to linear polymers. These protein-biocide conjugates mimicked the behavior of surface-presented polycationic biocides rather than their nonproteinaceous counterparts.
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Ammonium as sole N source improves grain quality in wheat.
Fuertes-Mendizábal, Teresa; González-Torralba, Jon; Arregui, Luis M; González-Murua, Carmen; González-Moro, M Begoña; Estavillo, José M
2013-07-01
The skilful handling of N fertilizer, including N source type and its timing, is necessary to obtain maximum profitability in wheat crops in terms of production and quality. Studies on grain yield and quality with ammonium as sole N source have not yet been conducted. The aim of this study was to evaluate the effect of N source management (nitrate vs. ammonium), and splitting it into two or three amendments during the wheat life cycle, on grain yield and quality under irrigated conditions. This experiment demonstrates that Cezanne wheat plants growing with ammonium as exclusive N source are able to achieve the same yield as plants growing with nitrate and that individual wheat plants grown in irrigated pots can efficiently use late N applied in GS37. Ammonium nutrition increased both types of grain reserve proteins (gliadins and glutenins) and also increased the ratio gli/glu with respect to nitrate nutrition. The splitting of the N rate enhanced the ammonium effect on grain protein composition. The application of ammonium N source, especially when split into three amendments, has an analogous effect on grain protein content and composition to applications at a higher N rate, leading to higher N use efficiency. © 2012 Society of Chemical Industry.
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Changes in biotic and abiotic processes following mangrove clearing
Granek, Elise; Ruttenberg, Benjamin I.
2008-12-01
Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an
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Wheat EST resources for functional genomics of abiotic stress
Directory of Open Access Journals (Sweden)
Links Matthew G
2006-06-01
Full Text Available Abstract Background Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS project. Results We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets. Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. Conclusion We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in
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Abiotic drivers of Chihuahuan Desert plant communities
Laura Marie Ladwig
2014-01-01
Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...
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Ammonium nitrogen removal from coking wastewater by chemical precipitation recycle technology.
Zhang, Tao; Ding, Lili; Ren, Hongqiang; Xiong, Xiang
2009-12-01
Ammonium nitrogen removal from wastewater has been of considerable concern for several decades. In the present research, we examined chemical precipitation recycle technology (CPRT) for ammonium nitrogen removal from coking wastewater. The pyrolysate resulting from magnesium ammonium phosphate (MAP) pyrogenation in sodium hydroxide (NaOH) solution was recycled for ammonium nitrogen removal from coking wastewater. The objective of this study was to investigate the conditions for MAP pyrogenation and to characterize of MAP pyrolysate for its feasibility in recycling. Furthermore, MAP pyrolysate was characterized by scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) as well as X-ray diffraction (XRD). The MAP pyrolysate could be produced at the optimal condition of a hydroxyl (OH(-)) to ammonium molar ratio of 2:1, a heating temperature of 110 degrees C, and a heating time of 3h. Surface characterization analysis indicated that the main component of the pyrolysate was amorphous magnesium sodium phosphate (MgNaPO(4)). The pyrolysate could be recycled as a magnesium and phosphate source at an optimum pH of 9.5. When the recycle times were increased, the ammonium nitrogen removal ratio gradually decreased if the pyrolysate was used without supplementation. When the recycle times were increased, the ammonium nitrogen removal efficiency was not decreased if the added pyrolysate was supplemented with MgCl(2).6H(2)O plus Na(2)HPO(4).12H(2)O during treatment. A high ammonium nitrogen removal ratio was obtained by using pre-formed MAP as seeding material.
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Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun
2016-01-01
Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677
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Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths
Directory of Open Access Journals (Sweden)
Tatsuki Kunoh
2016-06-01
Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.
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Energy Technology Data Exchange (ETDEWEB)
Brosche, P. [DBI-EWI GmbH, Freiberg (Germany)
1996-08-01
Ammonia up to 8 Mol/kg and the ammonium-ion up to 5 Mol/kg were investigated by sensitrodes. Sensitrodes of different manufacturers, the influence of different salts, the temperature (25 and 50 C) and ammonia in mixture with the ammonium-ion were assessed in respect of the result for measuring. The functional correlation between the pH-value and the logarithmus for the ratio of ammonium-ion to ammonia in respect of the equation from Henderson and Hasselbalch was examined. The given concentration for ammonia respectively the ammonium-ion was compared with the calculated concentration of the calibration curve. The investigated sensitrodes may be installed in the manufacturing of ammonium salts in mixture with ammonia as measuring and controlling unit. (orig.) [Deutsch] Ammoniak bis 8 mol/kg und das Ammoniumion bis 5 mol/kg wurden mittels Sensitroden untersucht. Bewertet wurden Sensitroden verschiedener Hersteller, der Einfluss von Salzen, der Temperatur (25 und 50 C) und Ammoniak im Gemisch mit dem Ammoniumion auf das Messergebnis. Der funktionale Zusammenhang zwischen dem pH-Wert und dem Logarithmus des Verhaeltnisses von Ammoniumion und Ammoniak entsprechend der Gleichung von Henderson und Hasselbalch wurde untersucht. Die eingegebenen Konzentrationen an Ammoniak bzw. des Ammoniumions wurden mit den aus den Kalibrierungskurven errechneten Konzentrationen verglichen. Die untersuchten Sensitroden koennen in der Produktion von Ammoniumsalzen im Gemisch mit Ammoniak als Mess- und Steuergeraet eingesetzt werden. (orig.)
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Abiotic production of iodine molecules in irradiated ice
Choi, Wonyong; Kim, Kitae; Yabushita, Akihiro
2015-04-01
Reactive halogen species play an important role in Earth's environmental systems. Iodine compounds are related to ozone depletion event (ODE) during Antarctic spring, formation of CCN (cloud condensation nuclei), and controlling the atmospheric oxidizing capacity. However, the processes and mechanisms for abiotic formation of iodine compounds in polar region are still unclear. Although the chemical reactions taking place in ice are greatly different from those in aquatic environment, reaction processes of halogens in frozen condition have rarely studied compared to those in water. In this study, we investigated iodide oxidation to form triiodide (I3-) in ice phase under UV irradiation ( λ > 300 nm) and dark condition. The production of I3- through iodide oxidation, which is negligible in aqueous solution, was significantly accelerated in ice phase even in the absence of UV irradiation. The following release of gaseous iodine molecule (I2) to the atmosphere was also monitored by cavity ring-down spectroscopy (CRDS). We speculate that the markedly enhanced iodide oxidation in polycrystalline ice is due to the freeze concentration of iodides, protons, and dissolved oxygen in the ice crystal grain boundaries. The experiments conducted under ambient solar radiation of the Antarctic region (King George Island, 62°13'S 58°47'W, sea level) also confirmed that the generation of I3- via iodide oxidation process is enhanced when iodide is trapped in ice. The observed intrinsic oxidative transformation of iodide to generate I3-(aq) and I2(g) in frozen environment suggests a previously unknown pathway for the substantial release of reactive iodine species to the atmosphere.
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Socki, Richard A.; Niles, Paul B.; Gibson, Everett K., Jr.; Romanek, Christopher S.; Zhang, Chuanlun L.; Bissada, Kadry K.
2008-01-01
The recent detection of methane in the Martian atmosphere and the possibility that its origin could be attributed to biological activity, have highlighted the importance of understanding the mechanisms of methane formation and its usefulness as a biomarker. Much debate has centered on the source of the methane in hydrothermal fluids, whether it is formed biologically by microorganisms, diagenetically through the decomposition of sedimentary organic matter, or inorganically via reduction of CO2 at high temperatures. Ongoing research has now shown that much of the methane present in sea-floor hydrothermal systems is probably formed through inorganic CO2 reduction processes at very high temperatures (greater than 400 C). Experimental results have indicated that methane might form inorganically at temperatures lower still, however these results remain controversial. Currently, methane in continental hydrothermal systems is thought to be formed mainly through the breakdown of sedimentary organic matter and carbon isotope equilibrium between CO2 and CH4 is thought to be rarely present if at all. Based on isotopic measurements of CO2 and CH4 in two continental hydrothermal systems, we suggest that carbon isotope equilibration exists at temperatures as low as 155 C. This would indicate that methane is forming through abiotic CO2 reduction at lower temperatures than previously thought and could bolster arguments for an abiotic origin of the methane detected in the martian atmosphere.
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Process for obtaining ammonium uranyl tri carbonate
International Nuclear Information System (INIS)
Santos, L.R. dos; Riella, H.G.
1992-01-01
The procedure adopted for obtaining Ammonium Uranyl Carbonate (AUC) from uranium hexafluoride (U F 6 ) in a aqueous solutions of ammonium hydrogen carbonate is described in this work. The precipitation is made in temperature and pH controlled. This process consists of three steps: evaporation of U F 6 , AUC precipitation and filtration of the AUC slurry. An attempt is made of correlate the parameters involved in the precipitation process of AUC with its and U O 2 characteristics. (author)
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International Nuclear Information System (INIS)
Sugii, Mari Miura; Ferreira, Fábio Augusto de Souza; Müller, Karina Cogo; Lima, Debora Alves Nunes Leite; Groppo, Francisco Carlos; Imasato, Hidetake; Rodrigues-Filho, Ubirajara Pereira
2017-01-01
The antibiofilm effect of iodide quaternary ammonium methacryloxy silicate (IQAMS) in Transbond XT Light Cure Adhesive resin used for braces cementation was evaluated. Fourier Transform Infrared (FTIR) spectroscopy confirmed IQAMS formation and Scanning Electron Microscopy coupled to Energy-Dispersive X-ray Spectroscopy (SEM-EDS) revealed that as coating, the quaternary ammonium groups from IQAMS were homogeneously dispersed throughout the surface. When incorporated, the composite material presented homogeneous dispersion throughout the resin. Assays with Streptococcus mutans demonstrated enhanced antibiofilm effect for the IQAMS coated resin, with much lower colony-forming units (CFU), in comparison to incorporated IQAMS. Such a difference was assigned to low availability of quaternary ammonium groups at the surface of resin when IQAMS was incorporated, hindering its antibiofilm effect. Additionally, the incorporation of IQAMS led to slight decrease in ultimate bond strength (UBS) and shear bond strength (SBS), in comparison to the neat commercial resin. Thus, the synthesized IQAMS displays great potential as antibiofilm coating or sealant to prevent oral infections in brackets during orthodontic treatment. - Highlights: • Synthesis of ORMOSIL-based material with antibiofilm activity is performed. • Antibiofilm activity of the ORMOSIL-based material on commercial available resin for braces cementation is evaluated. • Antibiofilm ORMOSIL-based coating with potential application as varnish or sealant in orthodontic appliances is presented.
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Energy Technology Data Exchange (ETDEWEB)
Sugii, Mari Miura [Departamento de Odontologia Restaurativa, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Ferreira, Fábio Augusto de Souza, E-mail: ferreira.fabio.a.s@gmail.com [Grupo de Química de Materiais Híbridos e Inorgânicos, Instituto de Química de São Carlos – Universidade de São Paulo, São Carlos, SP 13563-120 (Brazil); Müller, Karina Cogo [Departamento de Ciências Fisiológicas, Área de Farmacologia, Anestesiologia e Terapeutica, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Lima, Debora Alves Nunes Leite [Departamento de Odontologia Restaurativa, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Groppo, Francisco Carlos [Departamento de Ciências Fisiológicas, Área de Farmacologia, Anestesiologia e Terapeutica, Faculdade de Odontologia de Piracicaba – Universidade de Campinas, Piracicaba, SP 13414-903 (Brazil); Imasato, Hidetake; Rodrigues-Filho, Ubirajara Pereira [Grupo de Química de Materiais Híbridos e Inorgânicos, Instituto de Química de São Carlos – Universidade de São Paulo, São Carlos, SP 13563-120 (Brazil); and others
2017-04-01
The antibiofilm effect of iodide quaternary ammonium methacryloxy silicate (IQAMS) in Transbond XT Light Cure Adhesive resin used for braces cementation was evaluated. Fourier Transform Infrared (FTIR) spectroscopy confirmed IQAMS formation and Scanning Electron Microscopy coupled to Energy-Dispersive X-ray Spectroscopy (SEM-EDS) revealed that as coating, the quaternary ammonium groups from IQAMS were homogeneously dispersed throughout the surface. When incorporated, the composite material presented homogeneous dispersion throughout the resin. Assays with Streptococcus mutans demonstrated enhanced antibiofilm effect for the IQAMS coated resin, with much lower colony-forming units (CFU), in comparison to incorporated IQAMS. Such a difference was assigned to low availability of quaternary ammonium groups at the surface of resin when IQAMS was incorporated, hindering its antibiofilm effect. Additionally, the incorporation of IQAMS led to slight decrease in ultimate bond strength (UBS) and shear bond strength (SBS), in comparison to the neat commercial resin. Thus, the synthesized IQAMS displays great potential as antibiofilm coating or sealant to prevent oral infections in brackets during orthodontic treatment. - Highlights: • Synthesis of ORMOSIL-based material with antibiofilm activity is performed. • Antibiofilm activity of the ORMOSIL-based material on commercial available resin for braces cementation is evaluated. • Antibiofilm ORMOSIL-based coating with potential application as varnish or sealant in orthodontic appliances is presented.
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Directory of Open Access Journals (Sweden)
Xinguo Mao
Full Text Available Abiotic stresses are major environmental factors that affect agricultural productivity worldwide. NAC transcription factors play pivotal roles in abiotic stress signaling in plants. As a staple crop, wheat production is severely constrained by abiotic stresses whereas only a few NAC transcription factors have been characterized functionally. To promote the application of NAC genes in wheat improvement by biotechnology, a novel NAC gene designated TaNAC67 was characterized in common wheat. To determine its role, transgenic Arabidopsis overexpressing TaNAC67-GFP controlled by the CaMV-35S promoter was generated and subjected to various abiotic stresses for morphological and physiological assays. Gene expression showed that TaNAC67 was involved in response to drought, salt, cold and ABA treatments. Localization assays revealed that TaNAC67 localized in the nucleus. Morphological analysis indicated the transgenics had enhanced tolerances to drought, salt and freezing stresses, simultaneously supported by enhanced expression of multiple abiotic stress responsive genes and improved physiological traits, including strengthened cell membrane stability, retention of higher chlorophyll contents and Na(+ efflux rates, improved photosynthetic potential, and enhanced water retention capability. Overexpression of TaNAC67 resulted in pronounced enhanced tolerances to drought, salt and freezing stresses, therefore it has potential for utilization in transgenic breeding to improve abiotic stress tolerance in crops.
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Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage
International Nuclear Information System (INIS)
Vollenweider, P.; Guenthardt-Goerg, Madeleine S.
2005-01-01
Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors. - The morphology and distribution of visible stress symptoms in tree foliage provides diagnostic tools to identify plant defense responses and differentiate stress from natural senescence symptoms
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Properties of the ammonium tartrate/EPR dosimeter
International Nuclear Information System (INIS)
Yordanov, N.D.; Gancheva, V.
2004-01-01
The EPR response of γ-irradiated ammonium tartrate on the absorbed dose of γ-rays up to 22 kGy as well as the changes in the shape of the EPR spectrum upon applied modulation amplitude and microwave power are reported. Also the possibility to use ammonium tartrate together with Mn 2+ magnetically diluted in MgO as an internal reference material is evaluated. The influence of the microwave power and the modulation amplitude on their dose response is investigated. The results show that the radiation-induced EPR spectrum of ammonium tartrate, obtained at a low microwave power is complex consisting several patterns and is more easily saturated than the Mn 2+ EPR spectrum. In this case the following settings of the EPR parameters are recommended: H mod ≤0.05 mT and 10≤P MW ≤13 mW. Using these parameters the dosimeters can be considered for use in intercomparisons
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Rushdi, Ahmed I; Simoneit, Bernd R T
2006-04-01
Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 ( composite function)C to 300 ( composite function)C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 ( composite function)C and 250 ( composite function)C, and were detectable and thus stable under hydrothermal conditions to temperatures acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 ( composite function)C and 250 ( composite function)C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.
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Early metabolic effects and mechanism of ammonium transport in yeast
International Nuclear Information System (INIS)
Pena, A.; Pardo, J.P.; Ramirez, J.
1987-01-01
Studies were performed to define the effects and mechanism of NH+4 transport in yeast. The following results were obtained. Glucose was a better facilitator than ethanol-H 2 O 2 for ammonium transport; low concentrations of uncouplers or respiratory inhibitors could inhibit the transport with ethanol as the substrate. With glucose, respiratory inhibitors showed only small inhibitory effects, and only high concentrations of azide or trifluoromethoxy carbonylcyanide phenylhydrazone could inhibit ammonium transport. Ammonium in the free state could be concentrated approximately 200-fold by the cells. Also, the addition of ammonium produced stimulation of both respiration and fermentation; an increased rate of H+ extrusion and an alkalinization of the interior of the cell; a decrease of the membrane potential, as monitored by fluorescent cyanine; an immediate decrease of the levels of ATP and an increase of ADP, which may account for the stimulation of both fermentation and respiration; and an increase of the levels of inorganic phosphate. Ammonium was found to inhibit 86Rb+ transport much less than K+. Also, while K+ produced a competitive type of inhibition, that produced by NH4+ was of the noncompetitive type. From the distribution ratio of ammonium and the pH gradient, an electrochemical potential gradient of around -180 mV was calculated. The results indicate that ammonium is transported in yeast by a mechanism similar to that of monovalent alkaline cations, driven by a membrane potential. The immediate metabolic effects of this cation seem to be due to an increased [H+]ATPase, to which its transport is coupled. However, the carriers seem to be different. The transport system studied in this work was that of low affinity
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Abiotic factors drives floristic variations of fern's metacommunity in an Atlantic Forest remnant.
Costa, L E N; Farias, R P; Santiago, A C P; Silva, I A A; Barros, I C L
2018-02-15
We analyzed floristic variations in fern's metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated from a redundancy analysis. We found 24 species belonging to 20 genera and 12 families. The fern's flora showed high floristic heterogeneity (>75% for most of the plot's associations). The fern's metacommunity was structured along an abiotic gradient modulated by temperature, luminosity, and relative soil moisture.
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Effect of abiotic and biotic stress factors analysis using machine learning methods in zebrafish.
Gutha, Rajasekar; Yarrappagaari, Suresh; Thopireddy, Lavanya; Reddy, Kesireddy Sathyavelu; Saddala, Rajeswara Reddy
2018-03-01
In order to understand the mechanisms underlying stress responses, meta-analysis of transcriptome is made to identify differentially expressed genes (DEGs) and their biological, molecular and cellular mechanisms in response to stressors. The present study is aimed at identifying the effect of abiotic and biotic stress factors, and it is found that several stress responsive genes are common for both abiotic and biotic stress factors in zebrafish. The meta-analysis of micro-array studies revealed that almost 4.7% i.e., 108 common DEGs are differentially regulated between abiotic and biotic stresses. This shows that there is a global coordination and fine-tuning of gene regulation in response to these two types of challenges. We also performed dimension reduction methods, principal component analysis, and partial least squares discriminant analysis which are able to segregate abiotic and biotic stresses into separate entities. The supervised machine learning model, recursive-support vector machine, could classify abiotic and biotic stresses with 100% accuracy using a subset of DEGs. Beside these methods, the random forests decision tree model classified five out of 8 stress conditions with high accuracy. Finally, Functional enrichment analysis revealed the different gene ontology terms, transcription factors and miRNAs factors in the regulation of stress responses. Copyright © 2017 Elsevier Inc. All rights reserved.
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Removal of ammonium ion from aqueous solution using natural Turkish clinoptilolite
International Nuclear Information System (INIS)
Karadag, Dogan; Koc, Yunus; Turan, Mustafa; Armagan, Bulent
2006-01-01
A study on ion exchange kinetics and equilibrium isotherms of ammonium ion on natural Turkish clinoptilolite (zeolite) was conducted using a batch experiment technique. The effects of relevant parameters, such as temperature, contact time and initial ammonium (NH 4 + ) concentration were examined, respectively. The pseudo first-order, pseudo second-order kinetic models and intraparticle diffusion model were used to describe the kinetic data. The pseudo second-order kinetic model provided excellent kinetic data fitting (R 2 > 0.990) and intraparticle diffusion effects ammonium uptake. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for ammonium uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters such as change in free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy (ΔS 0 ) were also determined. An examination of the thermodynamic parameters shows that the exchange of ammonium ion by clinoptilolite is a process occurring spontaneously and physical in nature at ambient conditions (25 deg. C). The process is also found to be exothermic. The results indicate that there is a significant potential for the natural Turkish clinoptilolite as an adsorbent material for ammonium removal from aqueous solutions
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Ammonium and methylammonium transport in Rhodobacter sphaeroides
Energy Technology Data Exchange (ETDEWEB)
Cordts, M.L.; Gibson, J.
1987-04-01
Rhodobacter spheroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH/sub 4//sup +/ to washed, nitrogen-free cell suspensions was followed by linear uptake of NH/sub 4//sup +/ from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH/sub 4//sup +/. Transport of NH/sub 4//sup +/ was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH/sub 4//sup +/ concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH/sub 4//sup +/-free cell suspensions, methylammonium (/sup 14/CH/sub 3/NH/sub 3//sup +/) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The /sup 14/CN/sub 3/NH/sub 3//sup +/ pool was not affected by methionine sulfoximine. Unlike NH/sub 4//sup +/ uptake, /sup 14/CH/sub 3/NH/sub 3//sup +/ uptake in nitrogen-free cell suspensions was repressed by growth in NH/sub 4//sup +/. These results suggest that R. sphaeroides may produce an NH/sub 4//sup +/-specific transport system in addition to the NH/sub 4//sup +///sup 14/CH/sub 3/NH/sub 3//sup +/ transporter. This second transporter is able to produce normal-size NH/sub 4//sup +/ pools but has very little affinity for /sup 14/CH/sub 3/NH/sub 3//sup +/ and is not repressed by growth in high concentrations of NH/sub 4//sup +/.
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Foyer, Christine H; Rasool, Brwa; Davey, Jack W; Hancock, Robert D
2016-03-01
Plants co-evolved with an enormous variety of microbial pathogens and insect herbivores under daily and seasonal variations in abiotic environmental conditions. Hence, plant cells display a high capacity to respond to diverse stresses through a flexible and finely balanced response network that involves components such as reduction-oxidation (redox) signalling pathways, stress hormones and growth regulators, as well as calcium and protein kinase cascades. Biotic and abiotic stress responses use common signals, pathways and triggers leading to cross-tolerance phenomena, whereby exposure to one type of stress can activate plant responses that facilitate tolerance to several different types of stress. While the acclimation mechanisms and adaptive responses that facilitate responses to single biotic and abiotic stresses have been extensively characterized, relatively little information is available on the dynamic aspects of combined biotic/abiotic stress response. In this review, we consider how the abiotic environment influences plant responses to attack by phloem-feeding aphids. Unravelling the signalling cascades that underpin cross-tolerance to biotic and abiotic stresses will allow the identification of new targets for increasing environmental resilience in crops. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
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Safko, Trevor M; Faleiros, Marcelo M; Atvars, Teresa D Z; Weiss, Richard G
2016-06-16
An intramolecular exciplex-mediated, proton-coupled, charge-transfer (PCCT) process has been investigated for a series of N,N-dimethyl-3-(1-pyrenyl)propan-1-ammonium cations with different anions (PyS) in solvents of low to intermediate polarity over a wide temperature range. Solvent mediates both the equilibrium between conformations of the cation that place the pyrenyl and ammonium groups in proximity (conformation C) or far from each other (conformation O) and the ability of the ammonium group to transfer a proton adiabatically in the PyS excited singlet state. Thus, exciplex emission, concurrent with the PCCT process, was observed only in hydrogen-bond accepting solvents of relatively low polarity (tetrahydrofuran, ethyl acetate, and 1,4-dioxane) and not in dichloromethane. From the exciplex emission and other spectroscopic and thermodynamic data, the acidity of the ammonium group in conformation C of the excited singlet state of PyS (pKa*) has been estimated to be ca. -3.4 in tetrahydrofuran. The ratios between the intensities of emission from the exciplex and the locally excited state (IEx/ILE) appear to be much more dependent on the nature of the anion than are the rates of exciplex formation and decay, although the excited state data do not provide a quantitative measure of the anion effect on the C-O equilibrium. The activation energies associated with exciplex formation in THF are calculated to be 0.08 to 0.15 eV lower than for the neutral amine, N,N-dimethyl-3-(1-pyrenyl)propan-1-amine. Decay of the exciplexes formed from the deprotonation of PyS is hypothesized to occur through charge-recombination processes. To our knowledge, this is the first example in which photoacidity and intramolecular exciplex formation (i.e., a PCCT reaction) are coupled.
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Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator
Dandan Wu; Wenhui Ma; Yingbo Mao; Jiushuai Deng; Shuming Wen
2017-01-01
In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The ...
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Evaluation of Abiotic Resource LCIA Methods
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Rodrigo A. F. Alvarenga
2016-02-01
Full Text Available In a life cycle assessment (LCA, the impacts on resources are evaluated at the area of protection (AoP with the same name, through life cycle impact assessment (LCIA methods. There are different LCIA methods available in literature that assesses abiotic resources, and the goal of this study was to propose recommendations for that impact category. We evaluated 19 different LCIA methods, through two criteria (scientific robustness and scope, divided into three assessment levels, i.e., resource accounting methods (RAM, midpoint, and endpoint. In order to support the assessment, we applied some LCIA methods to a case study of ethylene production. For RAM, the most suitable LCIA method was CEENE (Cumulative Exergy Extraction from the Natural Environment (but SED (Solar Energy Demand and ICEC (Industrial Cumulative Exergy Consumption/ECEC (Ecological Cumulative Exergy Consumption may also be recommended, while the midpoint level was ADP (Abiotic Depletion Potential, and the endpoint level was both the Recipe Endpoint and EPS2000 (Environmental Priority Strategies. We could notice that the assessment for the AoP Resources is not yet well established in the LCA community, since new LCIA methods (with different approaches and assessment frameworks are showing up, and this trend may continue in the future.
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The Role of Tomato WRKY Genes in Plant Responses to Combined Abiotic and Biotic Stresses
Directory of Open Access Journals (Sweden)
Yuling Bai
2018-06-01
Full Text Available In the field, plants constantly face a plethora of abiotic and biotic stresses that can impart detrimental effects on plants. In response to multiple stresses, plants can rapidly reprogram their transcriptome through a tightly regulated and highly dynamic regulatory network where WRKY transcription factors can act as activators or repressors. WRKY transcription factors have diverse biological functions in plants, but most notably are key players in plant responses to biotic and abiotic stresses. In tomato there are 83 WRKY genes identified. Here we review recent progress on functions of these tomato WRKY genes and their homologs in other plant species, such as Arabidopsis and rice, with a special focus on their involvement in responses to abiotic and biotic stresses. In particular, we highlight WRKY genes that play a role in plant responses to a combination of abiotic and biotic stresses.
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Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O
2014-09-01
During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the
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Separation of ammonium and hydroxylamine nitrogen for the 15N determination
International Nuclear Information System (INIS)
Russow, R.
1990-01-01
After preseparation of the nitrogen compounds derived from microbial nitrification on a strong basic anion exchanger it is found hydroxylamine together with ammonium in one fraction. The nitrogen of this two compounds can be separated for the emission spectrometric 15 N analysis by the selective oxidation of the hydroxylamine to nitrite/nitrate using an iodine solution. Thus the hydroxylamine is protected against disproportionation during the following ammonium isolation by means of steam disillation in an alkaline medium. After that the nitrite/nitrate is reduced to ammonium using ferrous hydroxide and can than be librated by steam distillation. The performance of the method under discussion will be demonstrated by analysing solutions with known ammonium and hydroxylamine contents. (author)
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Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution
Weber, A. L.
1985-01-01
The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.
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Photochemical organonitrate formation in wet aerosols
Lim, Yong Bin; Kim, Hwajin; Kim, Jin Young; Turpin, Barbara J.
2016-10-01
Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen sulfates (CHNOS). These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH), two main products for both AS and SA aerosols were organonitrates, which appeared at m / z- 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.
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Cultivation, detection, and ecophysiology of anaerobic ammonium-oxidizing bacteria.
Kartal, Boran; Geerts, Wim; Jetten, Mike S M
2011-01-01
Anaerobic ammonium-oxidizing (anammox) bacteria oxidize ammonium with nitrite under anoxic conditions. The anammox process is currently used to remove ammonium from wastewater and contributes significantly to the loss of fixed nitrogen from the oceans. In this chapter, we focus on the ecophysiology of anammox bacteria and describe new methodologies to grow these microorganisms. Now, it is possible to enrich anammox bacteria up to 95% with a membrane bioreactor that removes forces of selection for fast settling aggregates and facilitates the growth of planktonic cells. The biomass from this system has a high anaerobic ammonium oxidation rate (50 fmol NH(4)(+) · cell(-1) day(-1)) and is suitable for many ecophysiological and molecular experiments. A high throughput Percoll density gradient centrifugation protocol may be applied on this biomass for further enrichment (>99.5%) of anammox bacteria. Furthermore, we provide an up-to-date list of commonly used primers and introduce protocols for quantification and detection of functional genes of anammox bacteria in their natural environment. Copyright © 2011 Elsevier Inc. All rights reserved.
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Producing ammonium sulfate from flue gas desulfurization by-products
Chou, I.-Ming; Bruinius, J.A.; Benig, V.; Chou, S.-F.J.; Carty, R.H.
2005-01-01
Emission control technologies using flue gas desulfurization (FGD) have been widely adopted by utilities burning high-sulfur fuels. However, these technologies require additional equipment, greater operating expenses, and increased costs for landfill disposal of the solid by-products produced. The financial burdens would be reduced if successful high-volume commercial applications of the FGD solid by-products were developed. In this study, the technical feasibility of producing ammonium sulfate from FGD residues by allowing it to react with ammonium carbonate in an aqueous solution was preliminarily assessed. Reaction temperatures of 60, 70, and 80??C and residence times of 4 and 6 hours were tested to determine the optimal conversion condition and final product evaluations. High yields (up to 83%) of ammonium sulfate with up to 99% purity were achieved under relatively mild conditions. The optimal conversion condition was observed at 60??C and a 4-hour residence time. The results of this study indicate the technical feasibility of producing ammonium sulfate fertilizer from an FGD by-product. Copyright ?? Taylor & Francis Inc.
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stripping of uranium from DEHPA/TOPO solvent by ammonium carbonate solutions
International Nuclear Information System (INIS)
Khorfan, S.; Shino, O.; Wahood, A.; Dahdouh, A.
2002-01-01
Uranium is recovered from phosphoric acid by the DEHPA/TOPO process. In this process uranium is stripped from the loaded DEHPA/TOPO solvent in the second cycle by an ammonium carbonate solution. This paper studied stripping of uranium from 0.3 Mol DEHPA/0.075 Mol TOPO in kerosene by different ammonium carbonate solutions. The ammonium carbonate solutions tested were either made locally from ammonia and carbon dioxide gases or commercial and laboratory grades available on the market. A comparison was made between these carbonate solutions in terms of purity, stripping efficiency and phase separation. Both stripping and phase separation were carried out under different conditions of phase ratio and concentrations. The results obtained showed that ammonium carbonate prepared from direct synthesis of ammonia and carbon dioxide gases had a high purity and gave the same stripping yield as the laboratory grade. The phase separation was also slightly improved using a pure synthesized ammonium carbonate solution. the phase separation was found to be best at concentration of 0.5 Mol/L ammonium carbonate solution and at a phase A/O of 1/1 and a temperature of 50 degree centigrade. It was possible to obtain >99% yield by operating 2 stripping stages counter currently under these conditions. (authors)
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Energy Technology Data Exchange (ETDEWEB)
Jalani, Hitesh B.; Venkateswararao, Edda; Manickam, Manoj; Jung, Sang Hun [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon (Korea, Republic of)
2016-12-15
An efficient, practical, straight forward, and transition metal-free three-component synthesis of diversely substituted imidazoles and 2H-imidazolones from β-ketoamines, acylating agents, and ammonium acetate has been described herein. This approach involves [3+1+1] cyclization through consecutive formation of three C–N bonds as a sequence of initial amidation of β-ketoamines with acylating agent, β-iminoketoamide formation with ammonia, and acid catalyzed concomitant cyclodehydration to afford the imidazoles and 2H-imidazolones. This methodology has advantages such as single flask operation, readily available starting materials, mild conditions, broad functional groups tolerance, and simple work-up procedure.
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Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.
Lenoir, Ingrid; Fontaine, Joël; Lounès-Hadj Sahraoui, Anissa
2016-03-01
The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Songlin Fei; Kim C. Steiner; James C. Finley; Marc E. McDill
2003-01-01
A series of substantial field surveys of 38 mixed-oak stands in central Pennsylvania were carried out during 1996-2000. All the stands were surveyed 1 year prior to harvest, and 16 stands have been surveyed 1 year after harvest. Three abiotic factors at stand scale, four abiotic factors at plot scale, and two biotic factors and one abiotic factor at subplot scale was...
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Photometric Determination of Ammonium and Phosphate in Seawater Medium Using a Microplate Reader.
Ruppersberg, Hanna S; Goebel, Maren R; Kleinert, Svea I; Wünsch, Daniel; Trautwein, Kathleen; Rabus, Ralf
2017-01-01
To more efficiently process the large sample numbers for quantitative determination of ammonium (NH4+) and phosphate (orthophosphate, PO43-) generated during comprehensive growth experiments with the marine Roseobacter group member Phaeobacter inhibens DSM 17395, specific colorimetric assays employing a microplate reader (MPR) were established. The NH4+ assay is based on the reaction of NH4+ with hypochlorite and salicylate, yielding a limit of detection of 14 µM, a limit of quantitation of 36 µM, and a linear range for quantitative determination up to 200 µM. The PO43-assay is based on the complex formation of PO43- with ammonium molybdate in the presence of ascorbate and zinc acetate, yielding a limit of detection of 13 µM, a limit of quantitation of 50 µM, and a linear range for quantitative determination up to 1 mM. Both MPR-based assays allowed for fast (significantly lower than 1 h) analysis of 21 samples plus standards for calibration (all measured in triplicates) and showed only low variation across a large collection of biological samples. © 2017 S. Karger AG, Basel.
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Abiotic stress responses in plants: roles of calmodulin-regulated proteins
Virdi, Amardeep S.; Singh, Supreet; Singh, Prabhjeet
2015-01-01
Intracellular changes in calcium ions (Ca2+) in response to different biotic and abiotic stimuli are detected by various sensor proteins in the plant cell. Calmodulin (CaM) is one of the most extensively studied Ca2+-sensing proteins and has been shown to be involved in transduction of Ca2+ signals. After interacting with Ca2+, CaM undergoes conformational change and influences the activities of a diverse range of CaM-binding proteins. A number of CaM-binding proteins have also been implicated in stress responses in plants, highlighting the central role played by CaM in adaptation to adverse environmental conditions. Stress adaptation in plants is a highly complex and multigenic response. Identification and characterization of CaM-modulated proteins in relation to different abiotic stresses could, therefore, prove to be essential for a deeper understanding of the molecular mechanisms involved in abiotic stress tolerance in plants. Various studies have revealed involvement of CaM in regulation of metal ions uptake, generation of reactive oxygen species and modulation of transcription factors such as CAMTA3, GTL1, and WRKY39. Activities of several kinases and phosphatases have also been shown to be modulated by CaM, thus providing further versatility to stress-associated signal transduction pathways. The results obtained from contemporary studies are consistent with the proposed role of CaM as an integrator of different stress signaling pathways, which allows plants to maintain homeostasis between different cellular processes. In this review, we have attempted to present the current state of understanding of the role of CaM in modulating different stress-regulated proteins and its implications in augmenting abiotic stress tolerance in plants. PMID:26528296
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Sacaliuc, E.; Friedrich, H.; Palkovits, R.; Weckhuysen, B.M.; Nijhuis, T.A.
2008-01-01
Postsynthesis ammonium treatment induces a substantial increase in the catalytic activity of Au/Ti-SBA-15 catalysts for the direct vapor-phase epoxidation of propylene using hydrogen and oxygen. The PO formation rate of a calcined Au/Ti-SBA-15 catalyst prepared by this method increased from 4.3 mgPO
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The Role of MAPK Modules and ABA during Abiotic Stress Signaling
Zélicourt, Axel de
2016-05-01
To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses in plants, triggering major changes in plant physiology. The ABA core signaling pathway largely relies on the activation of SnRK2 kinases to mediate several rapid responses, including gene regulation, stomatal closure, and plant growth modulation. Mitogen-activated protein kinases (MAPKs) have also been implicated in ABA signaling, but an entire ABA-activated MAPK module was uncovered only recently. In this review, we discuss the evidence for a role of MAPK modules in the context of different plant ABA signaling pathways. Abiotic stresses impact average yield in agriculture by more than 50% globally.Since ABA is a key regulator of abiotic stress responses, an understanding of its functioning at the molecular level is essential for plant breeding. Although the ABA core signaling pathway has been unraveled, several downstream events are still unclear.MAPKs are involved in most plant developmental stages and in response to stresses. Several members of the MAPK family were shown to be directly or indirectly activated by the ABA core signaling pathway.Recent evidence shows that the complete MAP3K17/18-MKK3-MPK1/2/7/14 module is under the control of ABA, whose members are under the transcriptional and post-translational control of the ABA core signaling pathway. © 2016 Elsevier Ltd.
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Effects of Calcium Lignosulfonate and Silicic Acid on Ammonium Nitrate Degradation
Directory of Open Access Journals (Sweden)
Ahmet Ozan Gezerman
2014-01-01
Full Text Available Ammonium nitrate salts are the most commonly used nitrogenous fertilizers in industry. However, storage of ammonium nitrate is problematic, since its initial properties can decline because of environmental factors, leading to large economic losses. In this study, in order to prevent the caking and degradation of ammonium nitrate, an alternative composition with additional calcium lignosulfonate and silicic acid was studied. The resulting fertilizer was analyzed by screening analysis, ion chromatography, and electron microscopy methods.
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Wiessner, A; Kappelmeyer, U; Kaestner, M; Schultze-Nobre, L; Kuschk, P
2013-09-01
The correlation between nitrogen removal and the role of the plants in the rhizosphere of constructed wetlands are the subject of continuous discussion, but knowledge is still insufficient. Since the influence of plant growth and physiological activity on ammonium removal has not been well characterized in constructed wetlands so far, this aspect is investigated in more detail in model wetlands under defined laboratory conditions using Juncus effusus for treating an artificial sewage. Growth and physiological activity, such as plant transpiration, have been found to correlate with both the efficiency of ammonium removal within the rhizosphere of J. effusus and the methane formation. The uptake of ammonium by growing plant stocks is within in a range of 45.5%, but under conditions of plant growth stagnation, a further nearly complete removal of the ammonium load points to the likely existence of additional nitrogen removal processes. In this way, a linear correlation between the ammonium concentration inside the rhizosphere and the transpiration of the plant stocks implies that an influence of plant physiological activity on the efficiency of N-removal exists. Furthermore, a linear correlation between methane concentration and plant transpiration has been estimated. The findings indicate a fast response of redox processes to plant activities. Accordingly, not only the influence of plant transpiration activity on the plant-internal convective gas transport, the radial oxygen loss by the plant roots and the efficiency of nitrification within the rhizosphere, but also the nitrogen gas released by phytovolatilization are discussed. The results achieved by using an unplanted control system are different in principle and characterized by a low efficiency of ammonium removal and a high methane enrichment of up to a maximum of 72.7% saturation. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Directory of Open Access Journals (Sweden)
Viswanath eSankar
2014-05-01
Full Text Available Changes in biotic and abiotic factors can be reflected in the complex impedance spectrum of the microelectrodes chronically implanted into the neural tissue. The recording surface of the tungsten electrode in vivo undergoes abiotic changes due to recording site corrosion and insulation delamination as well as biotic changes due to tissue encapsulation as a result of the foreign body immune response. We reported earlier that large changes in electrode impedance measured at 1 kHz were correlated with poor electrode functional performance, quantified through electrophysiological recordings during the chronic lifetime of the electrode. There is a need to identity the factors that contribute to the chronic impedance variation. In this work, we use numerical simulation and regression to equivalent circuit models to evaluate both the abiotic and biotic contributions to the impedance response over chronic implant duration. COMSOL® simulation of abiotic electrode morphology changes provide a possible explanation for the decrease in the electrode impedance at long implant duration while biotic changes play an important role in the large increase in impedance observed initially.
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Reuse of ammonium fluoride generated in the uranium hexafluoride conversion
International Nuclear Information System (INIS)
Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M.; Riella, H.G
2010-01-01
The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U 3 Si 2 ) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF 6 ) conversion consist in obtaining U 3 Si 2 and / or U 3 O 8 through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF 4 . This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH 4 + ), fluoride (F - ), carbonate (CO 3 -- ) and low concentrations of uranium. The procedure is basically the recovery of NH 4 F and uranium, as UF 4 , through the crystallization of ammonium bifluoride (NH 4 HF 2 ) and, in a later step, the addition of UO 2 , occurring fluoridation and decomposition. The UF 4 obtained is further diluted in the UF 4 produced routinely at IPEN / CNEN-SP by a wet route process. (author)
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Importance of biotic and abiotic components in feedback between plants and soil
Hanzelková, Věra
2017-01-01
The plant-soil feedback affects the forming of a plant community. Plants affect their own species as well as other species. The plant-soil feedback can be both positive and negative. Plants affect soil, change its properties, and the soil affects the plants reciprocally. Soil components can be divided into biotic and abiotic ones. The abiotic component is represented by physical and chemical properties of the soil. The main properties are the soil structure, the soil moisture, the soil temper...
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Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator.
Wu, Dandan; Ma, Wenhui; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming
2017-05-18
In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The results of ICP analysis indicate that the dissolution of enhanced sulfurized malachite surface is significantly decreased. Zeta potential measurements indicate that a smaller isoelectric point value and a large number of copper-sulfide films formed on the malachite surface by enhancing sulfidation resulted in a large amount of sodium butyl xanthate absorbed onto the enhanced sulfurized malachite surface. EDS semi-quantitative analysis and XPS analysis show that malachite was easily sulfurized by sodium sulfide with ammonium ion. These results show that the addition of ammonium ion plays a significant role in the sulfidation of malachite and results in improved flotation performance.
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Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS.
Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David
2012-02-01
Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.
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Size effects on cation heats of formation. I. Methyl substitutions in nitrogenous compounds
International Nuclear Information System (INIS)
Leach, Sydney
2012-01-01
Graphical abstract: Heat of formation of cations as a function of ln(n) where n is the number of atoms in the ion: methyl substituted immonium cations. N = substitution at nitrogen sites, C = substitution at carbon sites. Highlights: ► Heats of formation of nitrogenous cations by graphical method relating to ion size. ► Methyl substitution in formamides, acetamides, immonium, amine, and imine cations. ► Methyl substitution in ammonium and amino cations. ► New studies ionization energies and heats of formation required in several cases. - Abstract: The heats of formation of molecular ions are often not known to better than 10 or 20 kJ/mol. The present study on nitrogenous compounds adopts the graphical approach of Holmes and Lossing which relates cation heats of formation to cation size. A study of methyl substitution in formamides and acetamides is followed by an examination of heat of formation data on carbon-site and nitrogen-site methyl substitution in immonium, amine, imine, ammonium and amino cations. The results provide tests of the validity of this graphical method and also suggest investigating or re-investigating the ionization energies and the heats of formation of several of the molecules studied.
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McArthur, D A; Knowles, N R
1992-09-01
In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACC(ox)) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis
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Pre-mRNA splicing repression triggers abiotic stress signaling in plants
Ling, Yu
2016-09-24
Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress- and ABA-responsive reporters RD29A
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Pre-mRNA splicing repression triggers abiotic stress signaling in plants
Ling, Yu; Alshareef, Sahar; Butt, Haroon; Lozano-Juste, Jorge; Li, Lixin; Galal, Aya A.; Moustafa, Ahmed; Momin, Afaque Ahmad Imtiyaz; Tashkandi, Manal; Richardson, Dale N.; Fujii, Hiroaki; Arold, Stefan T.; Rodriguez, Pedro L.; Duque, Paula; Mahfouz, Magdy M.
2016-01-01
Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress- and ABA-responsive reporters RD29A
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Balsanelli, Eduardo; de Baura, Válter Antonio; Pedrosa, Fábio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele
2014-01-01
H. seropedicae associates endophytically and epiphytically with important poaceous crops and is capable of promoting their growth. The molecular mechanisms involved in plant colonization by this microrganism are not fully understood. Exopolysaccharides (EPS) are usually necessary for bacterial attachment to solid surfaces, to other bacteria, and to form biofilms. The role of H. seropedicae SmR1 exopolysaccharide in biofilm formation on both inert and plant substrates was assessed by characterization of a mutant in the espB gene which codes for a glucosyltransferase. The mutant strain was severely affected in EPS production and biofilm formation on glass wool. In contrast, the plant colonization capacity of the mutant strain was not altered when compared to the parental strain. The requirement of EPS for biofilm formation on inert surface was reinforced by the induction of eps genes in biofilms grown on glass and polypropylene. On the other hand, a strong repression of eps genes was observed in H. seropedicae cells adhered to maize roots. Our data suggest that H. seropedicae EPS is a structural component of mature biofilms, but this development stage of biofilm is not achieved during plant colonization.
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Directory of Open Access Journals (Sweden)
Eduardo Balsanelli
Full Text Available H. seropedicae associates endophytically and epiphytically with important poaceous crops and is capable of promoting their growth. The molecular mechanisms involved in plant colonization by this microrganism are not fully understood. Exopolysaccharides (EPS are usually necessary for bacterial attachment to solid surfaces, to other bacteria, and to form biofilms. The role of H. seropedicae SmR1 exopolysaccharide in biofilm formation on both inert and plant substrates was assessed by characterization of a mutant in the espB gene which codes for a glucosyltransferase. The mutant strain was severely affected in EPS production and biofilm formation on glass wool. In contrast, the plant colonization capacity of the mutant strain was not altered when compared to the parental strain. The requirement of EPS for biofilm formation on inert surface was reinforced by the induction of eps genes in biofilms grown on glass and polypropylene. On the other hand, a strong repression of eps genes was observed in H. seropedicae cells adhered to maize roots. Our data suggest that H. seropedicae EPS is a structural component of mature biofilms, but this development stage of biofilm is not achieved during plant colonization.
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Glufosinate ammonium--some aspects of its mode of action in mammals.
Hack, R; Ebert, E; Ehling, G; Leist, K H
1994-05-01
The broad-spectrum herbicide glufosinate ammonium is a structural analogue of glutamate and acts in plants by inhibition of glutamine synthetase leading to a complete breakdown of ammonia metabolism. Owing to the structural analogy of glufosinate ammonium to glutamate, its effect on various glutamate-utilizing systems needed to be investigated in mammals. Although in laboratory animals glufosinate ammonium causes an inhibition of glutamine synthetase activity in different tissues, this inhibition led to slight increases of glutamate and ammonia levels at high sublethal and lethal doses only. After oral administration for 28 days, glufosinate ammonium had no effect on glutathione and carbohydrate metabolism and no effect on biosynthesis of non-essential amino acids in rats and dogs. Glufosinate ammonium does not interfere with various neurotransmitter receptors in vitro and does not influence the catecholamine neurotransmitter tissue concentrations after iv application. The results of these studies show that--in contrast to the plant metabolism--in mammals the inhibition of glutamine synthetase activity in various tissues does not lead to a breakdown of ammonia metabolism. The mammalian metabolism obviously compensates for this inhibition of glutamine synthetase activity by various other metabolic pathways. It is concluded that under the conditions of recommended use of glufosinate ammonium as an active ingredient in herbicides, a detrimental effect on the health of both users and consumers is extremely unlikely.
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Induction of abiotic stress tolerance in plants by endophytic microbes.
Lata, R; Chowdhury, S; Gond, S K; White, J F
2018-04-01
Endophytes are micro-organisms including bacteria and fungi that survive within healthy plant tissues and promote plant growth under stress. This review focuses on the potential of endophytic microbes that induce abiotic stress tolerance in plants. How endophytes promote plant growth under stressful conditions, like drought and heat, high salinity and poor nutrient availability will be discussed. The molecular mechanisms for increasing stress tolerance in plants by endophytes include induction of plant stress genes as well as biomolecules like reactive oxygen species scavengers. This review may help in the development of biotechnological applications of endophytic microbes in plant growth promotion and crop improvement under abiotic stress conditions. Increasing human populations demand more crop yield for food security while crop production is adversely affected by abiotic stresses like drought, salinity and high temperature. Development of stress tolerance in plants is a strategy to cope with the negative effects of adverse environmental conditions. Endophytes are well recognized for plant growth promotion and production of natural compounds. The property of endophytes to induce stress tolerance in plants can be applied to increase crop yields. With this review, we intend to promote application of endophytes in biotechnology and genetic engineering for the development of stress-tolerant plants. © 2018 The Society for Applied Microbiology.
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Abiotic transformation of estrogens in synthetic municipal wastewater: An alternative for treatment?
Energy Technology Data Exchange (ETDEWEB)
Marfil-Vega, Ruth [School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, 701 Engineering Research Center, Cincinnati, OH 45221-0071 (United States); Suidan, Makram T., E-mail: Makram.Suidan@uc.ed [School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, 701 Engineering Research Center, Cincinnati, OH 45221-0071 (United States); Mills, Marc A. [USEPA, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268 (United States)
2010-11-15
The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3 and EE2 in synthetic wastewater. Greater than 80% reduction in the parent compounds was achieved for each target chemical after 72 h with the remaining concentration distributed between aqueous and solid phases as follows: 13% and 7% for E1, 10% and 2% for E2, 6% and 2% for E3, and 8% and 3% for EE2, respectively. Testosterone, androstenedione and progesterone were also monitored in this study, and their concentrations were found to be in agreement with initially spiked amount. Data collected under laboratory conditions provided the basis for implementing new abiotic wastewater treatment technologies that use inexpensive materials. - Abiotic transformation of estrogens in wastewater matrices can be harnessed for improving their removal from the environment.
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Abiotic transformation of estrogens in synthetic municipal wastewater: An alternative for treatment?
International Nuclear Information System (INIS)
Marfil-Vega, Ruth; Suidan, Makram T.; Mills, Marc A.
2010-01-01
The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3 and EE2 in synthetic wastewater. Greater than 80% reduction in the parent compounds was achieved for each target chemical after 72 h with the remaining concentration distributed between aqueous and solid phases as follows: 13% and 7% for E1, 10% and 2% for E2, 6% and 2% for E3, and 8% and 3% for EE2, respectively. Testosterone, androstenedione and progesterone were also monitored in this study, and their concentrations were found to be in agreement with initially spiked amount. Data collected under laboratory conditions provided the basis for implementing new abiotic wastewater treatment technologies that use inexpensive materials. - Abiotic transformation of estrogens in wastewater matrices can be harnessed for improving their removal from the environment.
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Cortex proliferation in the root is a protective mechanism against abiotic stress.
Cui, Hongchang
2015-01-01
Although as an organ the root plays a pivotal role in nutrient and water uptake as well anchorage, individual cell types function distinctly. Cortex is regarded as the least differentiated cell type in the root, but little is known about its role in plant growth and physiology. In recent studies, we found that cortex proliferation can be induced by oxidative stress. Since all types of abiotic stress lead to oxidative stress, this finding suggests a role for cortex in coping with abiotic stress. This hypothesis was tested in this study using the spy mutant, which has an extra layer of cortex in the root. Interestingly, the spy mutant was shown to be hypersensitive to salt and oxidizing reagent applied to the leaves, but it was as tolerant as the wild type to these compounds in the soil. This result lends support to the notion that cortex has a protective role against abiotic stress arising from the soil.
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(Methyl)ammonium Transport in the Nitrogen-Fixing Bacterium Azospirillum brasilense
Van Dommelen, Anne; Keijers, Veerle; Vanderleyden, Jos; de Zamaroczy, Miklos
1998-01-01
An ammonium transporter of Azospirillum brasilense was characterized. In contrast to most previously reported putative prokaryotic NH4+ transporter genes, A. brasilense amtB is not part of an operon with glnB or glnZ which, in A. brasilense, encode nitrogen regulatory proteins PII and PZ, respectively. Sequence analysis predicts the presence of 12 transmembrane domains in the deduced AmtB protein and classifies AmtB as an integral membrane protein. Nitrogen regulates the transcription of the amtB gene in A. brasilense by the Ntr system. amtB is the first gene identified in A. brasilense whose expression is regulated by NtrC. The observation that ammonium uptake is still possible in mutants lacking the AmtB protein suggests the presence of a second NH4+ transport mechanism. Growth of amtB mutants at low ammonium concentrations is reduced compared to that of the wild type. This suggests that AmtB has a role in scavenging ammonium at low concentrations. PMID:9573149
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Sacaliuc-Parvulescu, E.; Friedrich, H.; Palkovits, R.; Weckhuysen, B.M.; Nijhuis, T.A.
2008-01-01
Postsynthesis ammonium treatment induces a substantial increase in the catalytic activity of Au/Ti- SBA-15 catalysts for the direct vapor-phase epoxidation of propylene using hydrogen and oxygen. The PO formation rate of a calcined Au/Ti-SBA-15 catalyst prepared by this method increased from 4.3
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Electrochemical sensing of ammonium ion at the water/1,6-dichlorohexane interface.
Ribeiro, José A; Silva, F; Pereira, Carlos M
2012-01-15
In this work, ion transfer and facilitated ion transfer of ammonium ion by a lipophilic cyclodextrin is investigated at the water/1,6-dichlorohexane micro-interface, using electrochemical approaches (cyclic voltammetry, differential pulse voltammetry and square wave voltammetry). The association constant has been obtained for the complex between ammonium ion and the cyclodextrin. Experimental conditions for the analytical determination of ammonium ion were established and a detection limit of 0.12 μM was obtained. The amperometric sensor gave a current response proportional to the ammonium ion concentration in the range from 4.2 to 66 μM. Copyright © 2011 Elsevier B.V. All rights reserved.
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Yan, Ailan; Liu, Chongxuan; Liu, Yuanyuan; Xu, Fen
2018-03-01
Microbially mediated ammonium oxidation is a major process affecting nitrogen transformation and cycling in natural environments. This study investigated whether ion exchange process can affect microbially mediated aerobic oxidation of ammonium in a hyporheic zone (HZ) sediments from the Columbia River at US Department of Energy's Hanford site, Washington State. Experiments were conducted using synthetic groundwater and river water to investigate their effect on ammonium oxidation. Results indicated that ammonium sorption through ion exchange reactions decreased the rate of ammonium oxidation, apparently resulting from the influence of the ion exchange on dissolved ammonium concentration, thus decreasing the bioavailability of ammonium for microbial oxidation. However, with the decrease in dissolved ammonium concentration, the sorbed ammonium released back to aqueous phase, and became bioavailable so that all the ammonium in the suspensions were oxidized. Our results implied a dynamic change in ammonium oxidation rates in an environment such as at HZ where river water and groundwater with different chemical compositions exchange frequently that can affect ammonium sorption and desorption through ion exchange reactions.
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Abscisic Acid and abiotic stress signaling.
Tuteja, Narendra
2007-05-01
Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant growth and development and plays an important role in integrating various stress signals and controlling downstream stress responses. Plants have to adjust ABA levels constantly in responce to changing physiological and environmental conditions. To date, the mechanisms for fine-tuning of ABA levels remain elusive. The mechanisms by which plants respond to stress include both ABA-dependent and ABA-independent processes. Various transcription factors such as DREB2A/2B, AREB1, RD22BP1 and MYC/MYB are known to regulate the ABA-responsive gene expression through interacting with their corrosponding cis-acting elements such as DRE/CRT, ABRE and MYCRS/MYBRS, respectively. Understanding these mechanisms is important to improve stress tolerance in crops plants. This article first describes the general pathway for plant stress response followed by roles of ABA and transcription factors in stress tolerance including the regulation of ABA biosynthesis.
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Energy Technology Data Exchange (ETDEWEB)
Kulshrestha, N., E-mail: niharikakul@gmail.com; Chatterjee, B.; Gupta, P.N., E-mail: guptapn07@yahoo.co.in
2014-05-01
Highlights: • Polyvinyl alcohol (PVA). • Ammonium thiocyanate (NH{sub 4}SCN). • Electrical conductivity. • Fractals. - Abstract: In this communication, films of polyvinyl alcohol (PVA) polymer complexed with ammonium thiocyanate (NH{sub 4}SCN) salt were studied. XRD (X-ray diffraction) was used to study the complexation of salt with the polymer matrix and amorphicity in the films. DSC (differential scanning calorimetry) studies showed that the glass transition temperatures (T{sub g}) of the PVA:NH{sub 4}SCN complexed films were less than pristine PVA. Raman analysis was analyzed in order to study the change in the vibrational bands due to the complexation of salt with PVA. Optical micrographs confirm the fractal formation in 75:25 and 70:30 PVA:NH{sub 4}SCN films. Ionic transference number was estimated by Wagner's polarization method and its large value indicates that conduction takes place mainly due to mobile ionic species. Maximum conductivity ∼10{sup −3} S/cm at room temperature was obtained for 70:30 ratio of PVA: NH{sub 4}SCN polymer electrolyte films.
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Makrlík, Emanuel; Sýkora, David; Böhm, Stanislav; Kvíčalová, Magdalena; Vaňura, Petr
2018-05-01
By means of electrospray ionisation mass spectrometry, it was evidenced experimentally that the ammonium cation (NH4+) reacts with the electroneutral [2.2.2]paracyclophane ligand (C24H24) to form the cationic complex [NH4(C24H24)]+. Moreover, applying quantum chemical calculations, the most probable conformation of the proven [NH4(C24H24)]+ complex was solved. In the complex [NH4(C24H24)]+ having a symmetry very close to C3, the 'central' cation NH4+ is coordinated by three strong bifurcated intramolecular hydrogen bonds to the corresponding six carbon atoms from the three benzene rings of [2.2.2]paracyclophane via cation-π interaction. Finally, the interaction energy, E(int), of the considered complex [NH4(C24H24)]+ was evaluated as -625.8 kJ/mol, confirming the formation of this fascinating complex species as well. It means that the [2.2.2]paracyclophane ligand can be considered as an effective receptor for the ammonium cation in the gas phase.
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[A case of ammonium urate urinary stones with anorexia nervosa].
Komori, K; Arai, H; Gotoh, T; Imazu, T; Honda, M; Fujioka, H
2000-09-01
A 27-year-old woman had been suffering from bulimia and habitual vomiting for about 7 years and was incidentally found to have right renal stones by computed tomography. She was referred to our hospital for the treatment of these caluculi. On admission, she presented with hypokalemia, hypochloremia and metabolic alkalosis and was diagnosed with anorexia nervosa. Following successful removal by percutaneous nephrolithotripsy and extracorporeal shockwave lithotripsy the stones were found to consist of pure ammonium urate. Since the urine of an anorexia nervosa patient tends to be rich in uric acid and ammonium, anorexia nervosa seems to be associated with ammonium urate urinary stones.
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The systems lanthanum (cerium, samarium) nitrate-tetramethyl-ammonium nitrate-water
International Nuclear Information System (INIS)
Zhuravlev, E.F.; Khisaeva, D.A.; Semenova, Eh.B.
1984-01-01
The method of cross sections at 25 and 50 deg C has been applied to study solubility in the systems lanthanum nitrate-tetramethyl ammonium nitrate-water (1), cesium (3) nitrate-tetramethyl ammonium nitrate-water (2) and samarium nitrate-tetramethyl ammonium nitrate-water (3). Crystallization fields of congruently dissolving compounds with 1:3 ratio of salt components (in system 1) and 1:2 ratio (in systems 2 and 3) are found in the systems. New solid phases are separated preparatively and subjected to chemical, differential thermal and IR spectroscopic analyses. Compositions of formed compounds are compared with the compositions known for nitrates of other representatives of light lanthanides
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Ammonium assmilation in spruce ectomycorrhizas
International Nuclear Information System (INIS)
Chalot, M.; Brun, A.; Botton, B.; Stewart, G.
1990-01-01
Assimilation of labelled NH 4 + into amino acids has been followed in ectomycorrhizal roots of spruce. Over an 18 h period of NH 4 + feeding, Gln, Glu and Ala became the most abundant amino acids. Gln was also the most highly labelled amino acid during the experiment, followed by Glu and Ala. This result indicates that Gln synthesis is an important ammonium utilization reaction in spruce mycorrhizas. Addition of MSX to NH 4 + fed mycorrhizas caused an inhibition of Gln accumulation with a corresponding increase in Glu, Ala and Asn levels. The supply of MSX induced a sharp diminution of 15 N enrichment in both amino and amido groups of glutamine. In contrast, the 15 N incorporation into Glu and derivatives (Ala and Asp) remained very high. This study demonstrates that the fungal glutamate dehydrogenase is quite operative in spruce ectomycorrhizas since it is able to sustain ammonium assimilation when glutamine synthetase is inhibited
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Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil
Directory of Open Access Journals (Sweden)
Yun Zhang
2014-01-01
Full Text Available A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP and 2-methylphosphinico-acetic acid (MPA, in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg. Soil samples were extracted with ammonium hydroxide solution 5% (v/v, concentrated, and reacted with trimethyl orthoacetate (TMOA in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC using a flame photometric detector (FPD. The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.
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Field dissipation and storage stability of glufosinate ammonium and its metabolites in soil.
Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan
2014-01-01
A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2-95.5%, 98.3-100.3%, and 99.3-99.6% with relative standard deviations (RSD) of 1.8-4.1%, 0.4-1.4%, and 1.3-2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30-2.93 days in an open field. In soil samples stored at -20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment.
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Field Dissipation and Storage Stability of Glufosinate Ammonium and Its Metabolites in Soil
Zhang, Yun; Wang, Kai; Wu, Junxue; Zhang, Hongyan
2014-01-01
A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% (v/v), concentrated, and reacted with trimethyl orthoacetate (TMOA) in the presence of acetic acid for derivatization. The derivatives were quantified by gas chromatography (GC) using a flame photometric detector (FPD). The linear correlation coefficients of glufosinate ammonium, MPP, and MPA in soil were 0.991, 0.999, and 0.999, respectively. The recoveries of this method for glufosinate ammonium, MPP, and MPA in soil were 77.2–95.5%, 98.3–100.3%, and 99.3–99.6% with relative standard deviations (RSD) of 1.8–4.1%, 0.4–1.4%, and 1.3–2.0%, respectively. Glufosinate ammonium dissipated rapidly in soil to MPA in hours and gradually degraded to MPP. The half-life of glufosinate ammonium degradation in soil was 2.30–2.93 days in an open field. In soil samples stored at −20°C glufosinate ammonium was stable for two months. The results of this study should provide guidance for the safe application of the herbicide glufosinate ammonium to agricultural products and the environment. PMID:25374604
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Abiotic factors drives floristic variations of fern’s metacommunity in an Atlantic Forest remnant
Directory of Open Access Journals (Sweden)
L. E. N. Costa
2018-02-01
Full Text Available Abstract We analyzed floristic variations in fern’s metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated from a redundancy analysis. We found 24 species belonging to 20 genera and 12 families. The fern’s flora showed high floristic heterogeneity (>75% for most of the plot’s associations. The fern’s metacommunity was structured along an abiotic gradient modulated by temperature, luminosity, and relative soil moisture.
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Temperature rising characteristics of ammonium diurante in microwave fields
International Nuclear Information System (INIS)
Liu Bingguo; Peng JinHui; Huang Daifu; Zhang Libo; Hu Jinming; Zhuang Zebiao; Kong Dongcheng; Guo Shenghui; Li Chunxiang
2010-01-01
The temperature rising characteristics of ammonium diurante, triuranium octaoxide (U 3 O 8 ), and their mixture were investigated under microwave irradiation, aiming at exploring newly theoretical foundation for advanced metallurgical methods. The temperature rising curves showed that ammonium diurante had weak capability to absorb microwave energy, while triuranium octaoxide had the very strong absorption capability. The temperature of mixture containing 20% of U 3 O 8 could rise from room temperature to 1171 K within 280 s. The ability to absorb microwave energy for the mixture with different ratios increased with the increase in the amount of U 3 O 8 . These are in good agreement with the results of Maxwell-Garnett effective medium theory. It is feasible to calcine ammonium diurante by adding of small amounts of U 3 O 8 in microwave fields.
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Nguyen, Minh Dong; Risgaard-Petersen, Nils; Sørensen, Jan; Brandt, Kristian K
2011-02-01
Knowledge on bioavailable ammonium sensu strictu (i.e., immediately available for cellular uptake) in soil is required to understand nutrient uptake processes in microorganisms and thus of vital importance for plant production. We here present a novel ammonium biosensor approach based on the lithoautotrophic ammonia-oxidizing bacterium Nitrosomonas europaea transformed with a luxAB sensor plasmid. Bioluminescence-based ammonium detection was achieved within 10 min with a quantification limit in liquid samples of ∼20 μM and a linear response range up to 400 μM. Biosensor and conventional chemical quantification of ammonium in soil solutions agreed well across a range of sample and assay conditions. The biosensor was subsequently applied for a solid phase-contact assay allowing for direct interaction of biosensor cells with soil particle-associated (i.e., exchangeable plus fixed) ammonium. The assay successfully quantified bioavailable ammonium even in unfertilized soil and demonstrated markedly higher ratios of bioavailable ammonium to water- or 2 M KCl-exchangeable ammonium in anoxic soil than in corresponding oxic soil. Particle-associated ammonium contributed by at least 74% and 93% of the total bioavailable pool in oxic and anoxic soil, respectively. The N. europaea biosensor should have broad relevance for environmental monitoring of bioavailable ammonium and processes depending on ammonium bioavailability.
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Dissimilatory nitrate reduction to nitrate, nitrous oxide, and ammonium by Pseudomonas putrefaciens.
Samuelsson, M O
1985-10-01
The influence of redox potential on dissimilatory nitrate reduction to ammonium was investigated on a marine bacterium, Pseudomonas putrefaciens. Nitrate was consumed (3.1 mmol liter-1), and ammonium was produced in cultures with glucose and without sodium thioglycolate. When sodium thioglycolate was added, nitrate was consumed at a lower rate (1.1 mmol liter-1), and no significant amounts of nitrite or ammonium were produced. No growth was detected in glucose media either with or without sodium thioglycolate. When grown on tryptic soy broth, the production of nitrous oxide paralleled growth. In the same medium, but with sodium thioglycolate, nitrous oxide was first produced during growth and then consumed. Acetylene caused the nitrous oxide to accumulate. These results and the mass balance calculations for different nitrogen components indicate that P. putrefaciens has the capacity to dissimilate nitrate to ammonium as well as to dinitrogen gas and nitrous oxide (denitrification). The dissimilatory pathway to ammonium dominates except when sodium thioglycolate is added to the medium.
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What do we really know about the role of microorganisms in iron sulfide mineral formation?
Picard, Aude A.; Gartman, Amy; Girguis, Peter R.
2016-01-01
Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.
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Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.
Directory of Open Access Journals (Sweden)
Gert Everaert
Full Text Available We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.
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Adsorption behavior of ammonium by a bioadsorbent - Boston ivy leaf powder
Institute of Scientific and Technical Information of China (English)
Haiwei Liu; Yuanhua Dong; Haiyun Wang; Yun Liu
2010-01-01
The adsorption behaviors of ammonium ions from aqueous solution by a novel bioadsorbent,the Boston ivy (Parthenocissus tricuspidata) leaf powder (BPTL) were investigated.The SEM images and FT-IR spectra were used to characterize BPTL.The mathematical models were used to analyze the adsorption kinetics and isotherms.The optimum pH range for ammonium adsorption by BPTL was found to be 5-10.The adsorption reached equilibrium at 14 hr,and the kinetic data were well fitted by the Logistic model.The intraparticle diffusion was the main rate-controlling step of the adsorption process.The high temperature was favorableto the ammonium adsorption by BPTL,indicating that the adsorption was endothermic.The adsorption equilibrium fitted well to both the Langrnuir model and Freundlich model,and the maximum monolayer adsorption capacities calculated from Langmuir model were 3.37,5.28 and 6.59 mg N/g at 15,25 and 35℃,respectively,which were comparable to those by reported minerals.Both the separation factor (RL) from the Langmuir model and Freundlich exponent (n) suggested that the ammonium adsorption by BPTL was favorable.Therefore,the Boston ivy leaf powder could be considered a novel bioadsorbent for ammonium removal from aqueous solution.
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Influence of nitrogen dioxide on the thermal decomposition of ammonium nitrate
Directory of Open Access Journals (Sweden)
Igor L. Kovalenko
2015-06-01
Full Text Available In this paper results of experimental studies of ammonium nitrate thermal decomposition in an open system under normal conditions and in NO2 atmosphere are presented. It is shown that nitrogen dioxide is the initiator of ammonium nitrate self-accelerating exothermic cyclic decomposition process. The insertion of NO2 from outside under the conditions of nonisothermal experiment reduces the characteristic temperature of the beginning of self-accelerating decomposition by 50...70 °C. Using method of isothermal exposures it is proved that thermal decomposition of ammonium nitrate in nitrogen dioxide atmosphere at 210 °C is autocatalytic (zero-order reaction. It was suggested that there is possibility of increasing the sensitivity and detonation characteristics of energy condensed systems based on ammonium nitrate by the insertion of additives which provide an earlier appearance of NO2 in the system.
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Glufosinate ammonium induces convulsion through N-methyl-D-aspartate receptors in mice.
Matsumura, N; Takeuchi, C; Hishikawa, K; Fujii, T; Nakaki, T
2001-05-18
Glufosinate ammonium, a broad-spectrum herbicide, causes convulsion in rodents and humans. Because of the structural similarities between glufosinate and glutamate, the convulsion induced by glufosinate ammonium may be ascribed to glutamate receptor activation. Three N-methyl-D-asparate (NMDA) receptor antagonists, dizocilpine, LY235959, and Compound 40, and an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist, NBQX, were coadministrated with glufosinate ammonium (80 mg/kg, intraperitoneally) in mice. Statistical analyses showed that the NMDA receptor antagonists markedly inhibited the convulsions, while the AMPA/kainate receptor antagonist had no effect on the convulsion. These results suggest that the convulsion caused by glufosinate ammonium is mediated through NMDA receptors.
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Vapour pressure of ammonium chloride aerosol: Effect of temperature and humidity
Pio, Casimiro A.; Harrison, Roy M.
The effect of relative humidity (RH) on the constant for dissociation of ammonium chloride into gaseous HCl and NH 3 has been estimated for different temperatures, using thermodynamic data. At RH over 75-85% the ammonium chloride aerosol exists in the liquid phase, with the dissociation constant two orders of magnitude lower at 98% RH than for solid aerosol at the same temperature. It is predicted that ammonium chloride aqueous aerosol forms predominantly in fogwater and cloud droplets, and in regions where local emissions of NH 3 are important.
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Lawrence R. Walker; Aaron B. Shiels; Peter J. Bellingham; Ashley D. Sparrow; Ned Fetcher; Fred H. Landau; Deborah J. Lodge
2013-01-01
Abiotic variables are critical drivers of succession in most primary seres, but how their influence on biota changes over time is rarely examined. Landslides provide good model systems for examining abiotic influences because they are spatially and temporally heterogeneous habitats with distinct abiotic and biotic gradients and post-landslide erosion. In an 18-year...
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Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng
2017-01-01
Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize ( Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses.
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Factors affecting ammonium uptake in streams - an inter-biome perspective
Jackson R Webster; Partick J. Mulholland; Jennifer L. Tanks; H. Maurice Valett; Walter K. Dodds; Bruce J. Peterson; William B. Bowden; Clifford N. Dahm; Stuart Findlay; Stanley V. Gregory; Nancy B. Grimm; Stephen K. Hamilton; Sherri L. Johnson; Eugenia Marti; William H. McDowell; Judy L. Meyer; Donna D. Morrall; Steven A. Thomas; Wilfred M. Wollhem
2003-01-01
1. The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and...
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Radiolysis of aqueous solutions of ammonium bicarbonate over a large dose range
DEFF Research Database (Denmark)
Draganic, Z.D.; Negrón-Mendoza, A.; Sehested, K.
1991-01-01
Oxygen-free aqueous solutions of 0.05 mol dm-3 ammonium and sodium bicarbonate were studied after receiving various doses of Co-60 gammas (0.01-400 kGy) or 0.5-20 Gy pulses of 10 Mev electrons. Formate and oxalate were found to be the main radiolytic products, in addition to trace amounts...... to the reformation of bicarbonate, where the reaction COO- + CO3- is particularly significant. Computer fitting of the data obtained gives k(COO- + HCO3-) = (2 +/- 0.4) x 10(3) dm3 mol-1 s-1, k(COO- + CO3-) = (5 +/- 1) x 10(7) dm3 mol-1 s-1, k(NH2 + HCO3-)
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Directory of Open Access Journals (Sweden)
Francisco Moreno-Marín
Full Text Available Eutrophication affects seagrasses negatively by increasing light attenuation through stimulation of biomass of fast-growing, bloom-forming algae and because high concentrations of ammonium in the water can be toxic to higher plants. We hypothesized nevertheless, that moderate amounts of nitrophilic macroalgae that coexists with seagrasses under eutrophic conditions, can alleviate the harmful effects of eutrophication on seagrasses by reducing ammonium concentrations in the seawater to non-toxic levels because such algae have a very large capacity to take up inorganic nutrients. We studied therefore how combinations of different ammonium concentrations (0, 25 and 50 μM and different standing stocks of macroalgae (i.e. 0, 1 and 6 layers of Ulva sp. affected survival, growth and net production of the seagrass Zostera noltei. In the absence of Ulva sp., increasing ammonium concentrations had a negative influence on the performance of Z. noltei. The presence of Ulva sp. without ammonium supply had a similar, but slightly smaller, negative effect on seagrass fitness due to light attenuation. When ammonium enrichment was combined with presence of Ulva sp., Ulva sp. ameliorated some of negative effects caused by high ammonium availability although Ulva sp. lowered the availability of light. Benthic microalgae, which increased in biomass during the experiment, seemed to play a similar role as Ulva sp.--they contributed to remove ammonium from the water, and thus, aided to keep the ammonium concentrations experienced by Z. noltei at relatively non-toxic levels. Our findings show that moderate amounts of drift macroalgae, eventually combined with increasing stocks of benthic microalgae, may aid seagrasses to alleviate toxic effects of ammonium under eutrophic conditions, which highlights the importance of high functional diversity for ecosystem resistance to anthropogenic disturbance.
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Neiner, Doinita; Sevryugina, Yulia V; Schubert, David M
2016-09-06
The compound known since the 19th century as ammonium octaborate was structurally characterized revealing the ammonium salt of the ribbon isomer of the heptaborate anion, [B7O9(OH)5](2-), with boric acid and water molecules. Of composition (NH4)2B7.75O12.63·4.88H2O, it approximates the classical ammonium octaborate composition (NH4)2B8O13·6H2O and has the structural formula {(NH4)2[B7O9(OH)5]}4·3B(OH)3·5H2O. It spontaneously forms at room temperature in solid-state mixtures of ammonium tetraborate and ammonium pentaborate. It crystallizes in the monoclinic space group P21/c with a = 11.4137(2) Å, b = 11.8877(2) Å, c = 23.4459(3) Å, β = 90.092(1)°, V = 3181.19(8) Å(3), and Z = 2 and contains well-ordered ammonium cations and [B7O9(OH)5](2-) anions and disordered B(OH)3 and H2O molecules linked by extensive H bonding. Expeditious solid-state formation of the heptaborate anion under ambient conditions has important implications for development of practical syntheses of industrially useful borates.
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Current trends in genetic manipulations to enhance abiotic and ...
African Journals Online (AJOL)
Hitherto, tolerant plants were mainly produced by classical breeding techniques. Success in breeding for better adapted varieties to abiotic and biotic stresses depends on the concerted efforts of various research domains including plant and cell physiology, molecular biology, genetics and breeding. However, such process ...
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Ammonia volatilization from surface-applied nitrogen solution of urea and ammonium nitrate
International Nuclear Information System (INIS)
Trivellin, Paulo Cezar Ocheuze; Stefanutti, Ronaldo; Lima Filho, Oscar Fontvo de; Tziboy, Edgar Alfredo Tzi; Oliveira Junior, Jovo Alberto de; Bendassolli, Jose Albertino
1996-08-01
The urea is one of the fertilizers more utilized in modern agriculture. One of the problems in the urea utilization is the ammonium volatilization, resulting in low utilization of N-fertilizers by the plants.The objective of this study it was to evaluate and to compare in laboratories conditions , utilizing the 15 N technic the soil's ammonium lost by volatilization associated a superficial application of nitrogen corresponding doses like urea solution and urea and ammonium nitrates solution
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Dissimilatory nitrate reduction to nitrate, nitrous oxide, and ammonium by Pseudomonas putrefaciens.
Samuelsson, M O
1985-01-01
The influence of redox potential on dissimilatory nitrate reduction to ammonium was investigated on a marine bacterium, Pseudomonas putrefaciens. Nitrate was consumed (3.1 mmol liter-1), and ammonium was produced in cultures with glucose and without sodium thioglycolate. When sodium thioglycolate was added, nitrate was consumed at a lower rate (1.1 mmol liter-1), and no significant amounts of nitrite or ammonium were produced. No growth was detected in glucose media either with or without sod...
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Directory of Open Access Journals (Sweden)
Juan A. Ragazzo-Sánchez
2016-12-01
Full Text Available Abiotic factors influenced the capacity of the strains to form biofilms. Classification of the adhesion type is related with the optical density measured on the biofilm formation of tested strains. The relationship between the biofilm formation in real values with theoretical values of the strains was used to determine the mechanism involved during mixed cultures.
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Energy Technology Data Exchange (ETDEWEB)
Morita, R. Y.; Barbosa, R. V.; Kloss, J.R., E-mail: julianaweber@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Dartamento de Quimica e Biologia
2015-07-15
Bentonite, which the main clay mineral is montmorillonite, are commercially attractive because of its abundance in nature. The clays can be modified by ion exchange reactions of ions contained in the interlayer region with cationic surfactants that include ammonium or phosphonium salts. The clays origin and the type of surfactants (modifiers) are the main factors in the alteration of physical and chemical properties of these materials. This study aims to characterize and compare the results of natural bentonite commercially available and the effect of treatments with quaternary ammonium salt and an organic compound free of ammonium salt. The FTIR and XRD results indicate the process of organophilization of clays after treatment with the surfactants. These treatments have altered the average particle size, suggesting the formation of agglomerates, which was showed in the SEM images. The results of surface area and particle size data indicated the presence of larger particles. Although the two surfactants have shown similarities in the investigated properties, the organoclays free of ammonium salt are more promising in terms of its use as well as for their preparation and solubility. (author)
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Thermophysical properties of hydroxyl ammonium ionic liquids
International Nuclear Information System (INIS)
Kurnia, K.A.; Wilfred, C.D.; Murugesan, T.
2009-01-01
The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices n D , T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature 'T d ' for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA)
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Tanaka, J; Yamashita, M; Yamamoto, T
1995-01-01
BASTA is a herbicide containing glufosinate ammonium 18.5% and a surface-active agent. There were six fatalities in 34 cases of glufosinate ammonium poisoning reported by the Japan Poison Information Center. To evaluate efficacy in the removal of glufosinate ammonium from the blood, two bottles were prepared containing 600 mL of heparinized bovine blood with 1 mL or 3 mL of BASTA. Direct hemoperfusion or hemodialysis was performed for two hours at a flow rate of 50 mL/min. The final glufosinate ammonium concentration of the blood bottle containing 1 mL of BASTA decreased to 96.9% of the initial concentration after direct hemoperfusion and to 0.5% after hemodialysis. The final glufosinate ammonium concentration of the bottle containing 3 mL of BASTA decreased to 62.2% after direct hemoperfusion and to 0.9% after hemodialysis. Hemodialysis is more effective than direct hemoperfusion for removal of glufosinate ammonium from blood.
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Directory of Open Access Journals (Sweden)
Mihail KANTOR
2018-03-01
Full Text Available Originally from Africa, watermelon is a staple crop in South Carolina and rich source of important phytochemicals that promote human health. As a result of many years of domestication and selection for desired fruit quality, modern watermelon cultivars are susceptible to biotic and abiotic stress. The present review discusses how genetic selection and breeding combined with geospatial technologies (precision agriculture may help enhance watermelon varieties for resistance to biotic and abiotic stress. Gene loci identified and selected in undomesticated watermelon accessions are responsible for resistance to diseases, pests and abiotic stress. Vegetable breeding programs use traditional breeding methodologies and genomic tools to introduce gene loci conferring biotic or abiotic resistance into the genome background of elite watermelon cultivars. This continuous approach of collecting, evaluating and identifying useful genetic material is valuable for enhancing genetic diversity and tolerance and combined with precision agriculture could increase food security in the Southeast.
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Energy Technology Data Exchange (ETDEWEB)
Mihelj, Tea, E-mail: tmihelj@irb.hr [Ruđer Bošković Institute, Department of Physical Chemistry, Laboratory for Synthesis and Processes of Self-assembling of Organic Molecules, Bijenička c. 54, P.O. Box 180, HR-10002 Zagreb (Croatia); Popović, Jasminka [Division for Materials Physics, Ruđer Bošković Institute, POB 180, HR-10002 Zagreb (Croatia); Skoko, Željko [Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, HR-10000 Zagreb (Croatia); Tomašić, Vlasta, E-mail: vlastom@irb.hr [Ruđer Bošković Institute, Department of Physical Chemistry, Laboratory for Synthesis and Processes of Self-assembling of Organic Molecules, Bijenička c. 54, P.O. Box 180, HR-10002 Zagreb (Croatia)
2014-09-10
Highlights: • Thermal behavior of quaternary ammonium n-dodecylsulfates is characterized. • Typical layered structure dominates in all examined compounds at room temperature. • The dimeric didodecylsulfate crystallizes in monoclinic space group P21/m. • Thermotropic phases formation characteristic for multi-tailed n-dodecylsulfates. • Multi-charged n-dodecylsulfates are soft crystals at higher temperatures. - Abstract: Five novel anhydrous catanionic dodecylsulfates containing multi-charged and multi-tailed quaternary ammonium centers were synthesized and examined with light microscopy, differential scanning calorimetry and X-ray powder diffraction. This study is an attempt to explain the relationship between chemical structure, molecular architecture, phase transition characteristics and thermodynamics and the nature of intermolecular interactions of the individual amphiphiles that ultimately lead to different mesomorphic product. All examined compounds are of typical layered structure at room temperature. The long spacing decreases linearly with the increase of either ionic head or n-dodecyl chain number. The thermal analysis of the examined multi-charged catanionics indicates thermotropic mesomorphism, whereas multi-tailed dodecylsulfates show only properties of soft crystals. Maltese crosses, oily streaks textures, stepped drops and fan-shaped textures affirmed the existence of various smectic mesophases at room and higher temperatures. Thermodynamically the most ordered compound is dimeric didodecylsulfate, and the most disordered is three-tailed dodecylsulfate. The addition of the new quaternary ammonium center or alkyl chain causes the increment of the lattice energy first, and it decreases by further changes in the structure. The temperatures of crystallization decrease by any mentioned addition.
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DETECTION OF THE AMMONIUM ION IN SPACE
International Nuclear Information System (INIS)
Cernicharo, J.; Tercero, B.; Fuente, A.; Domenech, J. L.; Cueto, M.; Carrasco, E.; Herrero, V. J.; Tanarro, I.; Marcelino, N.; Roueff, E.; Gerin, M.; Pearson, J.
2013-01-01
We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 1 0 -0 0 line of the deuterated ammonium ion, NH 3 D + . The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH 3 D + as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1 0 -0 0 transition of the ammonium ion, 262817 ± 6 MHz (3σ), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 ± 0.2) × 10 12 cm –2 . Assuming a deuterium enhancement similar to that of NH 2 D, we derive N(NH 4 + ) ≅ 2.6 × 10 13 cm –2 , i.e., an abundance for ammonium of a few 10 –11 .
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Resilience of cereal crops to abiotic stress: A review
African Journals Online (AJOL)
SAM
2014-07-16
Jul 16, 2014 ... Key words: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress. ... production of genetically modified (GM) crops, exo- genous use of osmo protectants etc. ... stressful environments is important to fulfill food demand of the ever-increasing world ...
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STRESS ECOLOGY IN FUCUS : ABIOTIC, BIOTIC AND GENETIC INTERACTIONS
Wahl, Martin; Jormalainen, Veijo; Eriksson, Britas Klemens; Coyer, James A.; Molis, Markus; Schubert, Hendrik; Dethier, Megan; Karez, Rolf; Kruse, Inken; Lenz, Mark; Pearson, Gareth; Rohde, Sven; Wikstrom, Sofia A.; Olsen, Jeanine L.; Lesser, M
2011-01-01
Stress regimes defined as the synchronous or sequential action of abiotic and biotic stresses determine the performance and distribution of species. The natural patterns of stress to which species are more or less well adapted have recently started to shift and alter under the influence of global
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AMMONIUM TOXICITY AND NITRATE RESPONSE OF AXENICALLY GROWN DACTYLORHIZA-INCARNATA SEEDLINGS
DIJK, E; ECK, N
1995-01-01
The response to ammonium- and nitrate-nitrogen of seedlings of the calcicole orchid species Dactylorhiza incarnata (L.) Soo was tested in axenic in vitro culture of c. 3-month-old protocorms. A pronounced toxicity of ammonium ions was observed. Seedlings raised from plants of a coastal population
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Biofilm formation by asymptomatic and virulent urinary tract infectious Escherichia coli strains
DEFF Research Database (Denmark)
Hancock, Viktoria; Ferrieres, Lionel; Klemm, Per
2007-01-01
have investigated the biofilm-forming capacity on abiotic surfaces of groups of ABU strains and UPEC strains in human urine. We found that there is a strong bias; ABU strains were significantly better biofilm formers than UPEC strains. Our data suggest that biofilm formation in urinary tract infectious...
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Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress
Alshareef, Sahar
2017-01-01
Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses
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Computer model of hydroponics nutrient solution pH control using ammonium.
Pitts, M; Stutte, G
1999-01-01
A computer simulation of a hydroponics-based plant growth chamber using ammonium to control pH was constructed to determine the feasibility of such a system. In nitrate-based recirculating hydroponics systems, the pH will increase as plants release hydroxide ions into the nutrient solution to maintain plant charge balance. Ammonium is an attractive alternative to traditional pH controls in an ALSS, but requires careful monitoring and control to avoid overdosing the plants with ammonium. The primary advantage of using NH4+ for pH control is that it exploits the existing plant nutrient uptake charge balance mechanisms to maintain solution pH. The simulation models growth, nitrogen uptake, and pH of a l-m2 stand of wheat. Simulation results indicated that ammonium-based control of nutrient solution pH is feasible using a proportional integral controller. Use of a 1 mmol/L buffer (Ka = 1.6 x 10(-6)) in the nutrient solution is required.
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A portable analyser for the measurement of ammonium in marine waters.
Amornthammarong, Natchanon; Zhang, Jia-Zhong; Ortner, Peter B; Stamates, Jack; Shoemaker, Michael; Kindel, Michael W
2013-03-01
A portable ammonium analyser was developed and used to measure in situ ammonium in the marine environment. The analyser incorporates an improved LED photodiode-based fluorescence detector (LPFD). This system is more sensitive and considerably smaller than previous systems and incorporates a pre-filtering subsystem enabling measurements in turbid, sediment-laden waters. Over the typical range for ammonium in marine waters (0–10 mM), the response is linear (r(2) = 0.9930) with a limit of detection (S/N ratio > 3) of 10 nM. The working range for marine waters is 0.05–10 mM. Repeatability is 0.3% (n =10) at an ammonium level of 2 mM. Results from automated operation in 15 min cycles over 16 days had good overall precision (RSD = 3%, n = 660). The system was field tested at three shallow South Florida sites. Diurnal cycles and possibly a tidal influence were expressed in the concentration variability observed.
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76 FR 46907 - Ammonium Nitrate Security Program
2011-08-03
... Maritime Transportation Security Act NAICS North American Industrial Classification System NPRM Notice of.... Commenters noted, for example, that equipment used for transporting bulk ammonium nitrate, such as hoppers...
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Impact of Post-Translational Modifications of Crop Proteins under Abiotic Stress
Directory of Open Access Journals (Sweden)
Akiko Hashiguchi
2016-12-01
Full Text Available The efficiency of stress-induced adaptive responses of plants depends on intricate coordination of multiple signal transduction pathways that act coordinately or, in some cases, antagonistically. Protein post-translational modifications (PTMs can regulate protein activity and localization as well as protein–protein interactions in numerous cellular processes, thus leading to elaborate regulation of plant responses to various external stimuli. Understanding responses of crop plants under field conditions is crucial to design novel stress-tolerant cultivars that maintain robust homeostasis even under extreme conditions. In this review, proteomic studies of PTMs in crops are summarized. Although the research on the roles of crop PTMs in regulating stress response mechanisms is still in its early stage, several novel insights have been retrieved so far. This review covers techniques for detection of PTMs in plants, representative PTMs in plants under abiotic stress, and how PTMs control functions of representative proteins. In addition, because PTMs under abiotic stresses are well described in soybeans under submergence, recent findings in PTMs of soybean proteins under flooding stress are introduced. This review provides information on advances in PTM study in relation to plant adaptations to abiotic stresses, underlining the importance of PTM study to ensure adequate agricultural production in the future.
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Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants
Directory of Open Access Journals (Sweden)
Aurelio Gómez-Cadenas
2013-03-01
Full Text Available Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms with little or no modifications. It has been successfully applied to the study of molecular phenotypes of plants in response to abiotic stress in order to find particular patterns associated to stress tolerance. These studies have highlighted the essential involvement of primary metabolites: sugars, amino acids and Krebs cycle intermediates as direct markers of photosynthetic dysfunction as well as effectors of osmotic readjustment. On the contrary, secondary metabolites are more specific of genera and species and respond to particular stress conditions as antioxidants, Reactive Oxygen Species (ROS scavengers, coenzymes, UV and excess radiation screen and also as regulatory molecules. In addition, the induction of secondary metabolites by several abiotic stress conditions could also be an effective mechanism of cross-protection against biotic threats, providing a link between abiotic and biotic stress responses. Moreover, the presence/absence and relative accumulation of certain metabolites along with gene expression data provides accurate markers (mQTL or MWAS for tolerant crop selection in breeding programs.
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Koeneke, M.
2017-12-01
Arsenic (As) is a naturally occurring contaminant in Cambodia that has been contaminating well-water sources of millions of people. Commonly, studies look into the biotic factors that cause the arsenic to be released from aquifer sediments to groundwater. However, abiotic release of As from sediments, though little studied, may also play key roles in As contamination of well water. The goal of this research is to quantitatively compare organic-carbon mediated abiotic and biotic release of arsenic from sediments to groundwater. Batch anaerobic incubation experiments under abiotic (sodium azide used to immobilize microbes) and biotic conditions were conducted using Cambodian aquifer sediments, four different organic carbon sources (sodium lactate, sodium citrate, sodium oxalate, and humic acid), and six different carbon concentrations (0, 1, 2.5, 5, 10, 25mg C/L). Dissolved arsenic, iron(Fe), and manganese(Mn) concentrations in the treatments were measured 112 days . In addition, sediment and solution carbon solution was measured . Collectively, these show how different carbon sources, different carbon concentrations, and how abiotic and biotic factors impact the release of arsenic from Cambodian sediments into aquifers. Overall, an introduction of organic carbon to the soil increases the amount of As released from the sediment. The biotic + abiotic and abiotic conditions seemed to play a minimal role in the amount of As released. Dissolved species analysis showed us that 100% of the As was As(V), Our ICP-MS results vary due to the heterogeneity of samples, but when high levels are Fe are seen in solution, we also see high levels of As. We also see higher As concentrations when there is a smaller amount of Mn in solution.
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Gao, Qing-Hai; Wang, Ya-Kun; Lu, Xiao-Min; Jia, Shuang-Shuang
2014-05-01
The present study evaluated the effects of exogenous silicon on growth and physiological characteristics of hydroponically cultured cucumber seedlings under ammonium stress. The results showed that the growth, especially the aerial part growth of cucumber seedlings cultured with ammonium were significantly inhibited than those with nitrate, especially after treatment for 10 d, the aerial part fresh mass of cucumber seedlings were reduced 6.17 g per plant. The accumulation of reactive oxygen species (ROS) was also promoted in cucumber seedlings under ammonium, and the contents of O2*- and H2O2 were significantly increased in cucumber leaves. With the exogenous silicon treatment, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) were significantly improved, the ability to remove reactive oxygen species was enhanced, the contents of O2*- and H2O2 were significantly reduced in cucumber leaves, decreasing the reactive oxygen damage to the cell membrane, and the ratio of electrolyte leakage and the content of MDA in cucumber leaves. Also, with exogenous silicon treatment, the plasma membrane and activity of vacuolar membrane H(+)-ATP was significantly increased, transport capacity of intracellular proton was improved, and the level of ammonium in cucumber body was significantly reduced, thereby reducing the toxicity of ammonium. In conclusion, exogenous silicon could relieve ammonium stress, by increasing the antioxidant enzyme activity, H(+)-ATP activity, and decreasing the ammonium content in cucumber seedlings.
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Overexpression of an abiotic-stress inducible plant protein in the ...
African Journals Online (AJOL)
STORAGESEVER
2008-09-17
Sep 17, 2008 ... the universal stress hormone, is supplied in the culture ... various abiotic stress like water deficit, high salinity and low temperature or exogenous ... period in a plant growth chamber (NIPPON, LHP-100-RDS, Tokyo,. Japan).
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Boopathy, Ramasamy; Karthikeyan, Sekar; Mandal, Asit Baran; Sekaran, Ganesan
2013-01-01
Ammonium ions are one of the most encountered nitrogen species in polluted water bodies. High level of ammonium ion in aqueous solution imparts unpleasant taste and odor problems, which can interfere with the life of aquatics and human population when discharged. Many chemical methods are developed and being used for removal of ammonium ion from aqueous solution. Among various techniques, adsorption was found to be the most feasible and environmentally friendly with the use of natural-activated adsorbents. Hence, in this study, coconut shell-activated carbon (CSAC) was prepared and used for the removal of ammonium ion by adsorption techniques. Ammonium chloride (analytical grade) was purchased from Merck Chemicals for adsorption studies. The CSAC was used to adsorb ammonium ions under stirring at 100 rpm, using orbital shaker in batch experiments. The concentration of ammonium ion was estimated by ammonia distillate, using a Buchi distillation unit. The influence of process parameters such as pH, temperature, and contact time was studied for adsorption of ammonium ion, and kinetic, isotherm models were validated to understand the mechanism of adsorption of ammonium ion by CSAC. Thermodynamic properties such as ∆G, ∆H, and ∆S were determined for the ammonium adsorption, using van't Hoff equation. Further, the adsorption of ammonium ion was confirmed through instrumental analyses such as SEM, XRD, and FTIR. The optimum conditions for the effective adsorption of ammonium ion onto CSAC were found to be pH 9.0, temperature 283 K, and contact time 120 min. The experimental data was best followed by pseudosecond order equation, and the adsorption isotherm model obeyed the Freundlich isotherm. This explains the ammonium ion adsorption onto CSAC which was a multilayer adsorption with intraparticle diffusion. Negative enthalpy confirmed that this adsorption process was exothermic. The instrumental analyses confirmed the adsorption of ammonium ion onto CSAC.
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Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.
Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte
2017-03-09
Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.
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Thermal and chemical analysis of ammonium uranates and intermediate oxides
International Nuclear Information System (INIS)
Farah, M.Y.; El-Fekey, S.A.
1977-01-01
NH + 4 /U ratio, in ammonium uranate, decreases markedly with lower pH of precipitation, dilution of ammonia used for washing as also rinsing by acetone, methanol, or boiling water and it varies between 0.23 and 0.54. Thermogravimetric plots indicated that variation in percentage loss of weight between 220 deg and 660 deg C was seriously influenced by washing mode. Storing UO 3 under ammonium nitrate solution revealed, that a fraction could have been introduced from aqueous media by cation exchange mechanism. The percentage decreases in weight between 220 deg and 660 deg C. increased from 1.9% for nuclear pure UO 3 , to 3,2% for the trioixde immersed in ammonium nitrate, indicating some uptake of ammonia, amounting to a value of 0.053 to NH + 4 /U. To elucidate the type of binding, the behavior during uranate calcination at various temperatures, durations and depth of calcined layers in tray, was investigated in function of NH + 4 /U ratio. Finally, the study suggested an analytical method for determination of uranium in pure ammonium uranate powders, applicable for both routine and academic works
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Abiotic factors drives floristic variations of fern’s metacommunity in an Atlantic Forest remnant
L. E. N. Costa; R. P. Farias; A. C. P. Santiago; I. A. A. Silva; I. C. L. Barros
2018-01-01
Abstract We analyzed floristic variations in fern’s metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated...
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Reduced blood flow increases the in vivo ammonium ion concentration in the RIF-1 tumor
International Nuclear Information System (INIS)
Constantinidis, Ioannis; Gamcsik, Michael P.
1995-01-01
Purpose: Previous studies from our laboratory have suggested that pooling of ammonium in tumor tissues may be caused by its inefficient removal due to the poor vasculature commonly found in tumors. The purpose of these experiments was to validate the relationship between tumor ammonium ion concentration and tumor blood flow, and to determine whether large concentrations of ammonium ion detected by Nuclear Magnetic Resonance (NMR) spectroscopy are either produced within the tumor or simply imported into the tumor through the blood stream. Methods and Materials: To test this hypothesis, we reduced blood flow in subcutaneously grown Radiation Induced Fibrosarcoma-1 (RIF-1) tumors, either by creating partial ischemia with a bolus injection of hydralazine or by occlusion with surgical sutures. 14 N and 31 P NMR spectroscopy were used to detect the presence of ammonium, and to assess the bioenergetic status of the tumors, respectively. Results: A correlation between ammonium ion concentration and (PCr(P i )) ratio was established for untreated tumors. An increase in the in vivo tumor ammonium ion concentration was observed for every tumor that experienced a reduction in blood flow caused by either hydralazine injection or suture ligation. Changes in ammonium ion concentration paralleled changes in the bioenergetics of hydralazine-treated tumors. Conclusion: Our results support the hypothesis that a reduction in tumor blood flow is responsible for the accumulation of ammonium in tumors, and that detected ammonium originated from within the tumor
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Removal of mercury (II), elemental mercury and arsenic from simulated flue gas by ammonium sulphide.
Ning, Ping; Guo, Xiaolong; Wang, Xueqian; Wang, Ping; Ma, Yixing; Lan, Yi
2015-01-01
A tubular resistance furnace was used as a reactor to simulate mercury and arsenic in smelter flue gases by heating mercury and arsenic compounds. The flue gas containing Hg(2+), Hg(0) and As was treated with ammonium sulphide. The experiment was conducted to investigate the effects of varying the concentration of ammonium sulphide, the pH value of ammonium sulphide, the temperature of ammonium sulphide, the presence of SO2 and the presence of sulphite ion on removal efficiency. The prepared adsorption products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The results showed that the optimal concentration of ammonium sulphide was 0.8 mol/L. The optimal pH value of ammonium sulphide was 10, and the optimal temperature of ammonium sulphide was 20°C.Under the optimum conditions, the removal efficiency of Hg(2+), Hg(0) and As could reach 99%, 88.8%, 98%, respectively. In addition, SO2 and sulphite ion could reduce the removal efficiency of mercury and arsenic from simulated flue gas.
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Anaerobic oxidation of methane and ammonium.
Strous, M.; Jetten, M.S.M.
2004-01-01
Anaerobic oxidation of methane and ammonium are two different processes catalyzed by completely unrelated microorganisms. Still, the two processes do have many interesting aspects in common. First, both of them were once deemed biochemically impossible and nonexistent in nature, but have now been
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ROS-mediated abiotic stress-induced programmed cell death in plants
Directory of Open Access Journals (Sweden)
Veselin ePetrov
2015-02-01
Full Text Available During the course of their ontogenesis, plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD. This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help to develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process.
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Directory of Open Access Journals (Sweden)
Rongrong Guo
2018-04-01
Full Text Available WRKY transcription factors are known to play important roles in plant responses to various abiotic and biotic stresses. The grape WRKY gene, WRKY3 was previously reported to respond to salt and drought stress, as well as methyl jasmonate and ethylene treatments in Vitis labrusca × V. vinifera cv. ‘Kyoho.’ In the current study, WRKY3 from the ‘Kyoho’ grape cultivar was constitutively expressed in Arabidopsis thaliana under control of the cauliflower mosaic virus 35S promoter. The 35S::VlWRKY3 transgenic A. thaliana plants showed improved salt and drought stress tolerance during the germination, seedling and the mature plant stages. Various physiological traits related to abiotic stress responses were evaluated to gain further insight into the role of VlWRKY3, and it was found that abiotic stress caused less damage to the transgenic seedlings than to the wild-type (WT plants. VlWRKY3 over-expression also resulted in altered expression levels of abiotic stress-responsive genes. Moreover, the 35S::VlWRKY3 transgenic A. thaliana lines showed improved resistance to Golovinomyces cichoracearum, but increased susceptibility to Botrytis cinerea, compared with the WT plants. Collectively, these results indicate that VlWRKY3 plays important roles in responses to both abiotic and biotic stress, and modification of its expression may represent a strategy to enhance stress tolerance in crops.
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Subsurface aeration of anaerobic groundwater : iron colloid formation and the nitrification process
Wolthoorn, A.
2003-01-01
Keywords: Iron, anaerobic groundwater, groundwater purification, heterogeneous oxidation, iron colloid formation, electron microscopy, nitrification In anaerobic groundwater iron and ammonium can be found in relatively high concentrations. These substances need to be removed when groundwater is used
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[Inhibitors of proteolytic enzymes under abiotic stresses in plants (review)].
Mosolov, V V; Valueva, T A
2011-01-01
Data on the role of proteolytic enzyme inhibitors in plant adaptation to various unfavorable environmental abiotic factors--water deficiency, salinization of soil, extreme temperatures, etc.--and also probable functions of proteinases inhibitors in natural plant senescense are considered.
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Anaerobic ammonium oxidation by anammox bacteria in the Black Sea RID B-8834-2011
DEFF Research Database (Denmark)
Kuypers, MMM; Sliekers, AO; Lavik, G.
2003-01-01
The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions(1). The conversion of nitrate to N(2) by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean(2......). Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N(2) in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing...... the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors(3). Nutrient profiles, fluorescently labelled RNA probes, (15)N tracer experiments and the distribution of specific 'ladderane' membrane lipids(4) indicate that ammonium diffusing upwards from the anoxic deep water is consumed...
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Ammonium (E-3-(4-hydroxy-3-methoxyphenylprop-2-enoate monohydrate
Directory of Open Access Journals (Sweden)
Li-Cai Zhu
2010-11-01
Full Text Available In structure of the title compound ammonium ferulate monohydrate, NH4+·C10H9O4−·H2O, O—H...O and N—H...O hydrogen bonds link the ammonium cations, ferulate anions and water molecules into a three-dimensional array. The ferulate anion is approximately planar, with a maximum deviation of 0.307 (2 Å.
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Influence on ammonium-sulphate fertilizer on P-uptake by upland rice
International Nuclear Information System (INIS)
Abdullah, N; Mitrosuhardjo, M.M.
1988-01-01
A greenhouse experiment to study the influence of ammonium -sulphate fertilizer on P-uptake by Atomita I/1 rice variety on latosol soil of Pasar Jumat has been conducted. Factorial experiment consisting of eight treatments was arrange in a fully randomized design. Each treatment was replicated three times. The rate of ammonium sulphate fertilizer was equivalent to 0, 30, 60, and 90 kg N/ha, and TSP at the rate of 90 and 180 kg P/ha. Ammonium sulphate fertilizer with 2% atom 15-N and TSP with specific activity of 0.2 mCi/g P2O5 were used in the experiment. The plant was harvested 70 days after planting, It was turned out that ammonium sulphate fertilizer gave a highly significant difference (p=<0.01) of dry weight of plant. The rate of TSP did not effect significantly on plant dry weight. Ammonium sulphate fertilizer gave highly significant difference on P-uptake. Fertilizer use efficiency was in the range of 3.88 - 6.60% for 90 kg P and 2.51 - 4.46% for 180 kg P. Fertilizer-N uptake was significantly increased (p=<0.05) with the increase of N rate. Rate of fertilizer-N use efficiency was in the range of 47-60% of the applied fertilizer. (authors). 4 refs, 9 tabs
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Reardon, Patrick N; Chacon, Stephany S; Walter, Eric D; Bowden, Mark E; Washton, Nancy M; Kleber, Markus
2016-04-05
The ability of plants and microorganisms to take up organic nitrogen in the form of free amino acids and oligopeptides has received increasing attention over the last two decades, yet the mechanisms for the formation of such compounds in soil environments remain poorly understood. We used Nuclear Magnetic Resonance (NMR) and Electron Paramagnetic Resonance (EPR) spectroscopies to distinguish the reaction of a model protein with a pedogenic oxide (Birnessite, MnO2) from its response to a phyllosilicate (Kaolinite). Our data demonstrate that birnessite fragments the model protein while kaolinite does not, resulting in soluble peptides that would be available to soil biota and confirming the existence of an abiotic pathway for the formation of organic nitrogen compounds for direct uptake by plants and microorganisms. The absence of reduced Mn(II) in the solution suggests that birnessite acts as a catalyst rather than an oxidant in this reaction. NMR and EPR spectroscopies are shown to be valuable tools to observe these reactions and capture the extent of protein transformation together with the extent of mineral response.
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CdTe/ZnS quantum dots as fluorescent probes for ammonium determination.
Yi, Kui-Yu
2016-06-01
Novel CdTe/ZnS quantum dot (QD) probes based on the quenching effect were proposed for the simple, rapid, and specific determination of ammonium in aqueous solutions. The QDs were modified using 3-mercaptopropionic acid, and the fluorescence responses of the CdTe/ZnS QD probes to ammonium were detected through regularity quenching. The quenching levels of the CdTe/ZnS QDs and ammonium concentration showed a good linear relationship between 4.0 × 10(-6) and 5.0 × 10(-4) mol/L; the detection limit was 3.0 × 10(-7) mol/L. Ammonium contents in synthetic explosion soil samples were measured to determine the practical applications of the QD probes and a probable quenching mechanism was described. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
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Abiotic factors influencing tropical dry forests regeneration
Directory of Open Access Journals (Sweden)
Ceccon Eliane
2006-01-01
Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.
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Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089
International Nuclear Information System (INIS)
Zherebtsov, Alexander; Dvoeglazov, Konstantine; Volk, Vladimir; Zagumenov, Vladimir; Zverev, Dmitriy; Tinin, Vasiliy; Kozyrev, Anatoly; Shamin, Dladimir; Tvilenev, Konstantin
2013-01-01
The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)
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Efflux pump induction by quaternary ammonium compounds and fluoroquinolone resistance in bacteria.
Buffet-Bataillon, Sylvie; Tattevin, Pierre; Maillard, Jean-Yves; Bonnaure-Mallet, Martine; Jolivet-Gougeon, Anne
2016-01-01
Biocides, primarily those containing quaternary ammonium compounds (QAC), are heavily used in hospital environments and various industries (e.g., food, water, cosmetic). To date, little attention has been paid to potential implications of QAC use in the emergence of antibiotic resistance, especially fluoroquinolone-resistant bacteria in patients and in the environment. QAC-induced overexpression of efflux pumps can lead to: cross resistance with fluoroquinolones mediated by multidrug efflux pumps; stress response facilitating mutation in the Quinolone Resistance Determining Region; and biofilm formation increasing the risk of transfer of mobile genetic elements carrying fluoroquinolone or QAC resistance determinants. By following the European Biocidal Product Regulation, manufacturers of QAC are required to ensure that their QAC-based biocidal products are safe and will not contribute to emerging bacterial resistance.
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MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS
Energy Technology Data Exchange (ETDEWEB)
Beyenal, Haluk [WSU; McLEan, Jeff [JCVI; Majors, Paul [PNNL; Fredrickson, Jim [PNNL
2013-11-14
The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.
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Ammonium recruitment and ammonia transport by E. coli ammonia channel AmtB
DEFF Research Database (Denmark)
Nygaard, Thomas Pedersen; Rovira, C.; Peters, Günther H.j.
2006-01-01
To investigate substrate recruitment and transport across the Escherichia coli Ammonia transporter B (AmtB) protein, we performed molecular dynamics simulations of the AmtB trimer. We have identified residues important in recruitment of ammonium and intraluminal binding sites selective of ammonium......, which provide a means of cation selectivity. Our results indicate that A162 guides translocation of an extraluminal ammonium into the pore lumen. We propose a mechanism for transporting the intraluminally recruited proton back to periplasm. Our mechanism conforms to net transport of ammonia and can...
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Constraints on superoxide mediated formation of manganese oxides
Directory of Open Access Journals (Sweden)
Deric R. Learman
2013-09-01
Full Text Available Manganese (Mn oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2- (both of biogenic and abiogenic origin as an effective oxidant of Mn(II leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III and Mn(III/IV oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide, a product of the reaction of O2- with Mn(II, inhibits the oxidation process presumably through the reduction of Mn(III. Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III-ligand complexes. While complexing ligands played a role in stabilizing Mn(III, they did not eliminate the inhibition of net Mn(III formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation.
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Nouri Nigjeh, Eslam; de Vries, Marcel; Bruins, Andries P.; Bischoff, Rainer; Permentier, Hjalmar P.
Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied the constant potential oxidation products of quaternary ammonium electrolytes using mass
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2013-06-12
... agricultural grade ammonium nitrate from Ukraine would likely lead to continuation or recurrence of dumping... the Order on solid agricultural grade ammonium nitrate from Ukraine would be likely to lead to... Ammonium Nitrate from Ukraine: Continuation of Antidumping Duty Order AGENCY: Import Administration...
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Detonation characteristics of ammonium nitrate products
Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der
2006-01-01
The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers
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Directory of Open Access Journals (Sweden)
Arjun Sham
Full Text Available Plants have evolved with intricate mechanisms to cope with multiple environmental stresses. To adapt with biotic and abiotic stresses, plant responses involve changes at the cellular and molecular levels. The current study was designed to investigate the effects of combinations of different environmental stresses on the transcriptome level of Arabidopsis genome using public microarray databases. We investigated the role of cyclopentenones in mediating plant responses to environmental stress through TGA (TGACG motif-binding factor transcription factor, independently from jasmonic acid. Candidate genes were identified by comparing plants inoculated with Botrytis cinerea or treated with heat, salt or osmotic stress with non-inoculated or non-treated tissues. About 2.5% heat-, 19% salinity- and 41% osmotic stress-induced genes were commonly upregulated by B. cinerea-treatment; and 7.6%, 19% and 48% of genes were commonly downregulated by B. cinerea-treatment, respectively. Our results indicate that plant responses to biotic and abiotic stresses are mediated by several common regulatory genes. Comparisons between transcriptome data from Arabidopsis stressed-plants support our hypothesis that some molecular and biological processes involved in biotic and abiotic stress response are conserved. Thirteen of the common regulated genes to abiotic and biotic stresses were studied in detail to determine their role in plant resistance to B. cinerea. Moreover, a T-DNA insertion mutant of the Responsive to Dehydration gene (rd20, encoding for a member of the caleosin (lipid surface protein family, showed an enhanced sensitivity to B. cinerea infection and drought. Overall, the overlapping of plant responses to abiotic and biotic stresses, coupled with the sensitivity of the rd20 mutant, may provide new interesting programs for increased plant resistance to multiple environmental stresses, and ultimately increases its chances to survive. Future research
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The Promoter of AtUSP Is Co-regulated by Phytohormones and Abiotic Stresses in Arabidopsis thaliana.
Bhuria, Monika; Goel, Parul; Kumar, Sanjay; Singh, Anil K
2016-01-01
Universal stress proteins (USPs) are known to be expressed in response to various abiotic stresses in a wide variety of organisms, such as bacteria, archaebacteria, protists, algae, fungi, plants, and animals. However, in plants, biological function of most of the USPs still remains obscure. In the present study, Arabidopsis USP gene ( AtUSP ) showed induction in response to abscisic acid (ABA) and various abiotic stresses viz . heat, dehydration, salt, osmotic, and cold stresses. Additionally, in silico analysis of AtUSP promoter identified several cis -elements responsive to phytohormones and abiotic stresses such as ABRE, ERE, DRE, and HSE, etc. To functionally validate the AtUSP promoter, the 1115 bp region of promoter was characterized under phytohormone and abiotic stress treatments. Deletion analysis of promoter was carried out by cloning the full length promoter (D0) and its three 5' deletion derivatives, D1 (964 bp), D2 (660 bp), and D3 (503 bp) upstream of the β-glucuronidase (GUS) reporter gene, which were then stably transformed in Arabidopsis plants. The AtUSP promoter (D0) showed minimal activity under non-stress conditions which was enhanced in response to phytohormone treatments (ABA and ACC) and abiotic stresses such as dehydration, heat, cold, salt, and osmotic stresses. The seedlings harboring D1 and D2 deletion fragments showed constitutive GUS expression even under control condition with increased activity almost under all the treatments. However, D3 seedlings exhibited complete loss of activity under control condition with induction under ACC treatment, dehydration, heat, oxidative, salt, and osmotic stresses. Thus, present study clearly showed that AtUSP promoter is highly inducible by phytohormones and multiple abiotic stresses and it can be exploited as stress inducible promoter to generate multi-stress tolerant crops with minimal effects on their other important traits.
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Poimenidou, Sofia V; Chrysadakou, Marilena; Tzakoniati, Aikaterini; Bikouli, Vasiliki C; Nychas, George-John; Skandamis, Panagiotis N
2016-11-21
Listeria monocytogenes is a foodborne pathogen able to tolerate adverse conditions by forming biofilms or by deploying stress resistant mechanisms, and thus manages to survive for long periods in food processing plants. This study sought to investigate the correlation between biofilm forming ability, tolerance to disinfectants and cell surface characteristics of twelve L. monocytogenes strains. The following attributes were evaluated: (i) biofilm formation by crystal violet staining method on polystyrene, and by standard cell enumeration on stainless steel and polystyrene; (ii) hydrophobicity assay using solvents; (iii) minimum inhibitory concentration (MIC) and biofilm eradication concentration (BEC) of peracetic acid (PAA) and quaternary ammonium compounds (QACs), and (iv) resistance to sanitizers (PAA 2000ppm; QACs 500ppm) of biofilms on polystyrene and stainless steel. After 72h of incubation, higher biofilm levels were formed in TSB at 20°C, followed by TSB at 37°C (P=0.087) and diluted TSB 1/10 at both 20 (P=0.005) and 37°C (P=0.004). Cells grown at 30°C to the stationary phase had significant electron donating nature and a low hydrophobicity, while no significant correlation of cell surface properties to biofilm formation was observed. Strains differed in MIC PAA and BEC PAA by 24- and 15-fold, respectively, while a positive correlation between MIC PAA and BEC PAA was observed (P=0.02). The MIC QACs was positively correlated with the biofilm-forming ability on stainless steel (P=0.03). Regarding the impact of surface type, higher biofilm populations were enumerated on polystyrene than on stainless steel, which were also more tolerant to disinfectants. Among all strains, the greatest biofilm producer was a persistent strain with significant tolerance to QACs. These results may contribute to better understanding of L. monocytogenes behavior and survival on food processing surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.
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Activation mechanism of ammonium ions on sulfidation of malachite (-201) surface by DFT study
Wu, Dandan; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming
2017-07-01
The activation mechanism of ammonium ions on the sulfidation of malachite (-201) was determined by density functional theory (DFT) calculations. Results of DFT calculations indicated that interlayer sulfidation occurs during the sulfidation process of malachite (-201). The absorption of both the ammonium ion and sulfide ion on the malachite (-201) surface is stronger than that of sulfur ion. After sulfidation was activated with ammonium ion, the Cu 3d orbital peak is closer to the Fermi level and characterized by a stronger peak value. Therefore, the addition of ammonium ions activated the sulfidation of malachite (-201), thereby improving the flotation performance.
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Pant, Atul; Parsons, Matthew T; Bertram, Allan K
2006-07-20
Using optical microscopy, we investigated the crystallization of aqueous ammonium sulfate droplets containing soot and kaolinite, as well as the crystallization of aqueous ammonium sulfate droplets free of solid material. Our results show that soot did not influence the crystallization RH of aqueous ammonium sulfate particles under our experimental conditions. In contrast, kaolinite increased the crystallization RH of the aqueous ammonium sulfate droplets by approximately 10%. In addition, our results show that the crystallization RH of aqueous ammonium sulfate droplets free of solid material does not depend strongly on particle size. This is consistent with conclusions made previously in the literature, based on comparisons of results from different laboratories. From the crystallization results we determined the homogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate droplets and the heterogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate particles containing kaolinite. Using classical nucleation theory and our experimental data, we determined that the interfacial tension between an ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is 0.064 +/- 0.003 J m(-2) (in agreement with our previous measurements), and the contact angle between an ammonium sulfate critical nucleus and a kaolinite surface is 59 +/- 2 degrees. On the basis of our results, we argue that soot will not influence the crystallization RH of aqueous ammonium sulfate droplets in the atmosphere, but kaolinite can significantly modify the crystallization RH of atmospheric ammonium sulfate droplets. As an example, the CRH50 (the relative humidity at which 50% of the droplets crystallize) ranges from about 41 to 51% RH when the diameter of the kaolinite inclusion ranges from 0.1 to 5 microm. For comparison, the CRH50 of aqueous ammonium sulfate droplets (0.5 microm diameter) free of solid material is
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DETECTION OF THE AMMONIUM ION IN SPACE
Energy Technology Data Exchange (ETDEWEB)
Cernicharo, J.; Tercero, B. [Deparment of Astrophysics, CAB, INTA-CSIC, Crta Torrejon-Ajalvir Km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Fuente, A. [Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares (Spain); Domenech, J. L.; Cueto, M.; Carrasco, E.; Herrero, V. J.; Tanarro, I. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Marcelino, N. [NRAO, 520 Edgemont Road, Charlottesville, VA 22902 (United States); Roueff, E. [Luth, Observatoire de Paris, CNRS UMR8102, Place J. Janssen F-92190 Meudon (France); Gerin, M. [LERMA, Observatoire de Paris, CNRS UMR8112 and Ecole Normale Superieure, 61 Avenue de lObservatoire, F-75014 Paris (France); Pearson, J., E-mail: jcernicharo@cab.inta-csic.es [Jet Propulsion Laboratory, 4800 Oak Grove Drive, MC 168-314, Pasadena, CA 91109 (United States)
2013-07-01
We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 1{sub 0}-0{sub 0} line of the deuterated ammonium ion, NH{sub 3}D{sup +}. The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH{sub 3}D{sup +} as the electric field over the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1{sub 0}-0{sub 0} transition of the ammonium ion, 262817 {+-} 6 MHz (3{sigma}), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 {+-} 0.2) Multiplication-Sign 10{sup 12} cm{sup -2}. Assuming a deuterium enhancement similar to that of NH{sub 2}D, we derive N(NH{sub 4}{sup +}) {approx_equal} 2.6 Multiplication-Sign 10{sup 13} cm{sup -2}, i.e., an abundance for ammonium of a few 10{sup -11}.
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On the influence of thiamine and ammonium ions on alcoholic fermentation
Maesen, Th.J.M.
1953-01-01
1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have
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Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari
2011-04-01
The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.
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Energy Technology Data Exchange (ETDEWEB)
Zhou, Hai [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Lv, Baoliang, E-mail: lbl604@sxicc.ac.cn [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Wu, Dong; Xu, Yao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)
2014-12-15
Graphical abstract: Co{sub 3}O{sub 4} nanowires with excellent ammonium perchlorate catalytic decomposition property were synthesized via a methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process in the presence of methanamide. - Abstract: Co{sub 3}O{sub 4} nanowires, with the length of tens of micrometers and the width of several hundred nanometers, were produced by a hydrothermal treatment and a post-anneal process. X-ray diffraction (XRD) result showed that the Co{sub 3}O{sub 4} nanowires belong to cubic crystal system. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis indicated that the Co{sub 3}O{sub 4} nanowires, composed by single crystalline nanoparticles, were of polycrystalline nature. On the basis of time-dependent experiments, methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process were used to explain the precursors' formation process of the polycrystalline Co{sub 3}O{sub 4} nanowires. The TGA experiments showed that the as-obtained Co{sub 3}O{sub 4} nanowires can catalyze the thermal decomposition of ammonium perchlorate (AP) effectively.
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Völgyi, Gergely; Béni, Szabolcs; Takács-Novák, Krisztina; Görög, Sándor
2010-01-05
A potentiometric titration study of organic base hydrohalides and quaternary ammonium salts using perchloric acid as the titrant and a mixture of acetic anhydride and acetic acid as the solvent was carried out and the titration mixture was analysed by NMR in order to clarify the chemistry of the reactions involved. It was found that in contrast to the general belief the formation of acetyl halides and titratable free acetate ion does not take place prior to the titration but NMR spectra proved the formation of acetyl halides in the course of the titration. This observation and the fact that the shape of the titration curves depends on the nature of the hydrohaloic acid bound to the base or of the anion in the quaternary ammonium salts led to the conclusion that the titrating agent is acetyl perchlorate formed in situ during the titration. Equations of the reactions involved in the titration process are shown in the paper.
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Campbell, M. T.; Walia, H.; Grondin, A.; Knecht, A.
2017-12-01
The development of abiotic stress tolerant crops (i.e. drought, salinity, or heat stress) requires the discovery of DNA sequence variants associated with stress tolerance-related traits. However, many traits underlying adaptation to abiotic stress involve a suite of physiological pathways that may be induced at different times throughout the duration of stress. Conventional single-point phenotyping approaches fail to fully capture these temporal responses, and thus downstream genetic analysis may only identify a subset of the genetic variants that are important for adaptation to sub-optimal environments. Although genomic resources for crops have advanced tremendously, the collection of phenotypic data for morphological and physiological traits is laborious and remains a significant bottleneck in bridging the phenotype-genotype gap. In recent years, the availability of automated, image-based phenotyping platforms has provided researchers with an opportunity to collect morphological and physiological traits non-destructively in a highly controlled environment. Moreover, these platforms allow abiotic stress responses to be recorded throughout the duration of the experiment, and have facilitated the use of function-valued traits for genetic analyses in major crops. We will present our approaches for addressing abiotic stress tolerance in cereals. This talk will focus on novel open-source software to process and extract biological meaningful data from images generated from these phenomics platforms. In addition, we will discuss the statistical approaches to model longitudinal phenotypes and dissect the genetic basis of dynamic responses to these abiotic stresses throughout development.
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Harfouche, Antoine; Meilan, Richard; Altman, Arie
2014-11-01
Abiotic stresses, such as drought, salinity and cold, are the major environmental stresses that adversely affect tree growth and, thus, forest productivity, and play a major role in determining the geographic distribution of tree species. Tree responses and tolerance to abiotic stress are complex biological processes that are best analyzed at a systems level using genetic, genomic, metabolomic and phenomic approaches. This will expedite the dissection of stress-sensing and signaling networks to further support efficient genetic improvement programs. Enormous genetic diversity for stress tolerance exists within some forest-tree species, and due to advances in sequencing technologies the molecular genetic basis for this diversity has been rapidly unfolding in recent years. In addition, the use of emerging phenotyping technologies extends the suite of traits that can be measured and will provide us with a better understanding of stress tolerance. The elucidation of abiotic stress-tolerance mechanisms will allow for effective pyramiding of multiple tolerances in a single tree through genetic engineering. Here we review recent progress in the dissection of the molecular basis of abiotic stress tolerance in forest trees, with special emphasis on Populus, Pinus, Picea, Eucalyptus and Quercus spp. We also outline practices that will enable the deployment of trees engineered for abiotic stress tolerance to land owners. Finally, recommendations for future work are discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Lichens as biomonitors of atmospheric ammonium/ammonia deposition in Portugal
International Nuclear Information System (INIS)
Capelao, A.L.; Maguas, C.; Branquinho, C.; Cruz, C.; Martins-Loucao, M.A.
2000-01-01
The aim of the present work was to evaluate the potentiality of lichens as biomonitors of NH 4 + /NH 3 (ammonium/ammonia) and NO 3 - (nitrate) atmospheric deposition. For that, we used as a field station a rice plantation which is submitted, once a year, to air spraying fertilization with a mixture of nitrogen sources. Samples of an epiphytic lichen, Ramalina fastigiata, were collected from an ash-tree bordering the rice-plantation by the Sorraia River Valley (Central Portugal). The study started one month before fertilization and sampling was carried out for five months. The concentration of ammonium in the lichen was highly and significantly correlated with the number of days without precipitation before sampling, and had an inverse correlation with fluorescence values. Under these conditions, the amount of NH 4 + found in the lichen appears to reflect ammonium/ammonia dry deposition. (author)
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Energy Technology Data Exchange (ETDEWEB)
Newbold, J D; Elwood, J W; Schulze, M S; Stark, R W; Barmeier, J C
1983-01-01
In order to test for nitrogen limitation and examine ammonium uptake by stream sediments, ammonium hydroxide was added continuously at concentrations averaging 100 /sup +/gl/sup -1/ for 70 days to a second-order reach of Walker Branch, an undisturbed woodland stream in Tennessee. Ammonium uptake during the first 4 h of addition corresponded to adsorption kinetics rather than to first-order uptake or to Michaelis-Menten kinetics. However, the calculated adsorption partition coefficient was two to four orders of magnitude greater than values reported for physical adsorption of ammonium, suggesting that the uptake was largely biotic. Mass balance indicated that the uptake of ammonium from the water could be accounted for by increased nitrogen content in benthic organic detritus. Nitrification, inferred from longitudinal gradients in NO/sub 3/, began soon after enrichment and increased dramatically near the end of the experiment. Both ammonium and nitrate concentrations dropped quickly to near background levels when input ceased, indicating little desorption or nitrification of excess nitrogen stored in the reach. There was no evidence of nitrogen limitation as measured by weight loss, oxygen consumption, phosphorus content, and macroinvertebrate density of red oak leaf packs, or by chlorophyll content and aufwuchs biomass on plexiglass slides. A continuous phosphorus enrichment 1 year earlier had demonstrated phosphorus limitation in Walker Branch. 38 references, 6 figures, 3 tables.
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Determination of ammonium on an integrated microchip with LED-induced fluorescence detection.
Xue, Shuhua; Uchiyama, Katsumi; Li, Hai-Fang
2012-01-01
A simply fabricated microfluidic device integrated with a fluorescence detection system has been developed for on-line determination of ammonium in aqueous samples. A 365-nm light-emitting diode (LED) as an excitation source and a minor band pass filter were mounted into a polydimethylsiloxane (PDMS)-based microchip for the purpose of miniaturization of the entire analytical system. The ammonium sample reacted with o-phthaldialdehyde (OPA) on-chip with sodium sulfite as reducing reagent to produce a fluorescent isoindole derivative, which can emit fluorescence signal at about 425 nm when excited at 365 nm. Effects of pH, flow rate of solutions, concentrations of OPA-reagent, phosphate and sulfite salt were investigated. The calibration curve of ammonium in the range of 0.018-1.8 microg/mL showed a good linear relationship with R2 = 0.9985, and the detection limit was (S/N = 3) 3.6 x 10(-4) microg/mL. The relative standard deviation was 2.8% (n = 11) by calculating at 0.18 microg/mL ammonium for repeated detection. The system was applied to determine the ammonium concentration in rain and river waters, even extent to other analytes fluorescence detection by the presented device.
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Sodium benzyl(monoethanol)ammonium bis(gluconatoborate)
International Nuclear Information System (INIS)
Tel'zhenskaya, P.N.; Shvarts, E.M.; Vitola, I.M.
1990-01-01
Boron compounds with gluconic acid and monoethanol- and benzylamines are synthesized and investigated by physicochemical methods (IR-spectroscopy, thermal decomposition, conductometry, Fischer titration). Tetracoordinated boron has two free hydroxyl groups, dimer of boron-gluconate anion is held by hydrogen bonds, sodium ions and ammonium protonated salts are cations
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Abiotic stressors and stress responses
DEFF Research Database (Denmark)
Sulmon, Cecile; Van Baaren, Joan; Cabello-Hurtado, Francisco
2015-01-01
Abstract Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we...... review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact...... life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental...
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Novel perspectives for the engineering of abiotic stress tolerance in plants.
Cabello, Julieta V; Lodeyro, Anabella F; Zurbriggen, Matias D
2014-04-01
Adverse environmental conditions pose serious limitations to agricultural production. Classical biotechnological approaches towards increasing abiotic stress tolerance focus on boosting plant endogenous defence mechanisms. However, overexpression of regulatory elements or effectors is usually accompanied by growth handicap and yield penalties due to crosstalk between developmental and stress-response networks. Herein we offer an overview on novel strategies with the potential to overcome these limitations based on the engineering of regulatory systems involved in the fine-tuning of the plant response to environmental hardships, including post-translational modifications, small RNAs, epigenetic control of gene expression and hormonal networks. The development and application of plant synthetic biology tools and approaches will add new functionalities and perspectives to genetic engineering programs for enhancing abiotic stress tolerance. Copyright © 2013 Elsevier Ltd. All rights reserved.
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ROS-mediated abiotic stress-induced programmed cell death in plants
Petrov, Veselin; Hille, Jacob; Mueller-Rober, Bernd; Gechev, Tsanko S.
2015-01-01
During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms
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Mi, Weixing; Zhao, Jianqiang; Ding, Xiaoqian; Ge, Guanghuan; Zhao, Rixiang
2017-12-01
To investigate the characteristics of anaerobic ammonia oxidation for treating low-ammonium wastewater, a continuous-flow completely autotrophic nitrogen removal over nitrite (CANON) biofilm reactor was studied. At a temperature of 32 ± 1 °C and a pH between 7.5 and 8.2, two operational experiments were performed: the first one fixed the hydraulic retention time (HRT) at 10 h and gradually reduced the influent ammonium concentrations from 210 to 50 mg L -1 ; the second one fixed the influent ammonium concentration at 30 mg L -1 and gradually decreased the HRT from 10 to 3 h. The results revealed that the total nitrogen removal efficiency exceeded 80%, with a corresponding total nitrogen removal rate of 0.26 ± 0.01 kg N m -3 d -1 at the final low ammonium concentration of 30 mg L -1 . Small amounts of nitrous oxide (N 2 O) up to 0.015 ± 0.004 kg m -3 d -1 at the ammonium concentration of 210 mg L -1 were produced in the CANON process and decreased with the decrease in the influent ammonium loads. High-throughput pyrosequencing analysis indicated that the dominant functional bacteria 'Candidatus Kuenenia' under high influent ammonium levels were gradually succeeded by Armatimonadetes_gp5 under low influent ammonium levels.
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A Model of Continental Growth and Mantle Degassing Comparing Biotic and Abiotic Worlds
Höning, D.; Hansen-Goos, H.; Spohn, T.
2012-12-01
While examples for interaction of the biosphere with the atmosphere can be easily cited (e.g., production and consumption of O2), interaction between the biosphere and the solid planet and its interior is much less established. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. We present an interaction model that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The mantle viscosity in this model depends on the water concentration in the mantle. We use boundary layer theory of mantle convection to parameterize the mantle convection flow rate and assume that the plate speed equals the mantle flow rate. The biosphere enters the calculation through the assumption that the continental erosion rate is enhanced by a factor of several through bioactivity and through an assumed reduction of the kinetic barrier to diagenetic and metamorphic reactions (e.g., Kim et al. 2004) in the sedimentary basins in subduction zones that would lead to increased water storage capacities. We further include a stochastic model of continent-to-continent interactions that limits the effective total length of subduction zones. We use present day parameters of the Earth and explore a phase plane spanned by the percentage of surface coverage of the Earth by continents and the total water content of the mantle. We vary the ratio of the erosion rate in a postulated abiotic Earth to the present Earth, as well as the activation barrier to diagenetic and metamorphic reactions that affect the water storage capacity of the subducting crust. We find stable and unstable fixed points in
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Kojima, Ryo; Arai, Teppei; Matsufuji, Hiroshi; Kasumi, Takafumi; Watanabe, Taisuke; Ogihara, Jun
2016-12-01
Penicillium purpurogenum is the fungus that produces an azaphilone pigment. However, details about the pigment biosynthesis pathway are unknown. The violet pigment PP-V is the one of the main pigments biosynthesized by this fungus. This pigment contains an amino group in a pyran ring as its core structure. We focused on this pigment and examined the relationship between intracellular ammonium concentration and pigment production using glutamine as a nitrogen source. The intracellular ammonium level decreased about 1.5-fold in conditions favoring PP-V production. Moreover, P. purpurogenum was transferred to medium in which it commonly produces the related pigment PP-O after cultivating it in the presence or absence of glutamine to investigate whether this fungus biosynthesizes PP-V using surplus ammonium in cells. Only mycelia cultured in medium containing 10 mM glutamine produced the violet pigment, and simultaneously intracellular ammonium levels decreased under this condition. From comparisons of the amount of PP-V that was secreted with quantity of surplus intracellular ammonium, it is suggested that P. purpurogenum maintains ammonium homeostasis by excreting waste ammonium as PP-V.
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A phenomenological model for improving understanding of the ammonium nitrate agglomeration process
Directory of Open Access Journals (Sweden)
Videla Leiva Alvaro
2016-01-01
Full Text Available Ammonium nitrate is intensively used as explosive in the mining industry as the main component of ANFO. The ammonium nitrate is known to be a strong hygroscopic crystal matter which generates problems due to the creation of water bridges between crystals leading later to nucleation and crystallization forming an agglomerated solid cake. The agglomeration process damages the ammonium nitrate performance and is undesirable. Usually either organic or inorganic coatings are used to control agglomeration. In the present work a characterization method of humidity adsorption of the ammonium nitrate crystal was performed under laboratory conditions. Several samples were exposed into a defined humidity in a controlled chamber during 5 hours after which the samples were tested to measure agglomeration as the resistance force to compression. A clear relation was found between coating protection level, humidity and agglomeration. Agglomeration can be then predicted by a phenomenological model based of combination of the mono-layer BET adsorption and CNT nucleation models.
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International Nuclear Information System (INIS)
Fait, Martin J.G.; Radnik, Jörg; Lunk, Hans-Joachim
2016-01-01
Highlights: • Detection of reduced tungsten ions at the solid’s surface in oxidising atmosphere. • Detection of gaseous ammonia liberated as oxidising agent. • Detection of ammonia’s oxidation products. • Quantification of the ammonia/tungsten redox process. - Abstract: The interaction of ammonia, liberated during thermal decomposition of ammonium paratungstate tetrahydrate in oxidising atmosphere, with tungsten has been studied employing a conventional microbalance combined with MS (Setaram’s instrument Sensys). Applying XPS a partial reduction of tungsten at the surface with the minimal tungsten oxidation number of +5.3 for a sample generated at 293 °C was detected. The balancing oxidation of ammonia to nitrogen/nitrogen oxides has been proven by MS. An amount of 0.049 mol e"− per mol W was transferred which resulted in an ammonia conversion degree from 2.1 mol% (NO_2 formation) to 3.0 mol% (N_2 formation).
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Energy Technology Data Exchange (ETDEWEB)
Fait, Martin J.G., E-mail: martin.fait@catalysis.de [Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059 Rostock (Germany); Radnik, Jörg [Leibniz-Institut für Katalyse e.V., Albert-Einstein-Strasse 29a, 18059 Rostock (Germany); Lunk, Hans-Joachim [2858 Lake RD, Towanda, PA 18848 (United States)
2016-06-10
Highlights: • Detection of reduced tungsten ions at the solid’s surface in oxidising atmosphere. • Detection of gaseous ammonia liberated as oxidising agent. • Detection of ammonia’s oxidation products. • Quantification of the ammonia/tungsten redox process. - Abstract: The interaction of ammonia, liberated during thermal decomposition of ammonium paratungstate tetrahydrate in oxidising atmosphere, with tungsten has been studied employing a conventional microbalance combined with MS (Setaram’s instrument Sensys). Applying XPS a partial reduction of tungsten at the surface with the minimal tungsten oxidation number of +5.3 for a sample generated at 293 °C was detected. The balancing oxidation of ammonia to nitrogen/nitrogen oxides has been proven by MS. An amount of 0.049 mol e{sup −} per mol W was transferred which resulted in an ammonia conversion degree from 2.1 mol% (NO{sub 2} formation) to 3.0 mol% (N{sub 2} formation).
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2011-08-10
... nitrate (``ammonium nitrate'') from the Russian Federation (``Russia'') would likely lead to continuation... Duty Order on Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation AGENCY: Import... ammonium nitrate suspended investigation. See Initiation of Five-Year (``Sunset'') Review, 76 FR 11202...
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Identification of the AQP members involved in abiotic stress responses from Arabidopsis.
Feng, Zhi-Juan; Xu, Sheng-Chun; Liu, Na; Zhang, Gu-Wen; Hu, Qi-Zan; Xu, Zhao-Shi; Gong, Ya-Ming
2018-03-10
Aquaporins (AQPs) constitute a highly diverse family of water channel proteins that play crucial biological functions in plant growth and development and stress physiology. In Arabidopsis, 35 AQPs are classified into four subfamilies (PIPs, TIPs, NIPs and SIPs). However, knowledge about the roles of different subfamily AQPs remains limited. Here, we explored the chromosomal location, gene structure and expression patterns of all AQPs in different tissues or under different abiotic stresses based on available microarray data. Tissue expression analysis showed that different AQPs had various expression patterns in tissues (root, leaf, flower and seed). Expression profiles under stress conditions revealed that most AQPs were responsive to osmotic, salt and drought stresses. Phenotypic and physiological identification showed that Tip2;2 loss-of-function mutant exhibited less sensitive to abiotic stresses (mannitol, NaCl and PEG) compared with wild-type, as evident by analysis of germination rate, root growth, survival rate, ion leakage, malondialdehyde (MDA) and proline contents. Mutant of TIP2;2 modulated the transcript levels of SOS1, SOS2, SOS3, DREB1A, DREB2A and P5CS1, under abiotic stress conditions. This study provides a basis for further functional identification of stress-related candidate AQPs in Arabidopsis. Copyright © 2017 Elsevier B.V. All rights reserved.
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Rubisco Activase Is Also a Multiple Responder to Abiotic Stresses in Rice.
Directory of Open Access Journals (Sweden)
Yue Chen
Full Text Available Ribulose-1,5-bisphosphate carboxylase/oxygenase activase (RCA is a nuclear gene that encodes a chloroplast protein that plays an important role in photosynthesis. Some reports have indicated that it may play a role in acclimation to different abiotic stresses. In this paper, we analyzed the stress-responsive elements in the 2.0 kb 5'-upstream regions of the RCA gene promoter and the primary, secondary and tertiary structure of the protein. We identified some cis-elements of multiple stress-related components in the RCA promoter. Amino acid and evolution analyses showed that the RCA protein had conserved regions between different species; however, the size and type varied. The secondary structures, binding sites and tertiary structures of the RCA proteins were also different. This might reflect the differences in the transcription and translation levels of the two RCA isoforms during adaptation to different abiotic stresses. Although both the transcription and translation levels of RCA isoforms in the rice leaves increased under various stresses, the large isoform was increased more significantly in the chloroplast stroma and thylakoid. It can be concluded that RCA, especially RCAL, is also a multiple responder to abiotic stresses in rice, which provides new insights into RCA functions.
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Glass transition behaviour of the quaternary ammonium type ionic liquid, {[DEME][I] + H2O} mixtures
International Nuclear Information System (INIS)
Imai, Yusuke; Abe, Hiroshi; Matsumoto, Hitoshi; Shimada, Osamu; Hanasaki, Tomonori; Yoshimura, Yukihiro
2011-01-01
By a simple DTA system, the glass transition temperatures of the quaternary ammonium type ionic liquid, {N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium iodide, [DEME][I] + H 2 O} mixtures after quick pre-cooling were measured as a function of water concentration (x mol% H 2 O). Results were compared with the previous results of {[DEME][BF 4 ] + H 2 O} mixtures in which double glass transitions were observed in the water concentration region of (16.5 to 30.0) mol% H 2 O. Remarkably, we observed the double glass transition phenomenon in {[DEME][I] + H 2 O} mixtures too, but the two-T g s regions lie towards the water-rich side of (77.5 to 85.0) mol% H 2 O. These clearly reflect the difference in the anionic effect between BF 4 - and I - on the water structure. The end of the glass-formation region of {[DEME][I] + H 2 O} mixtures is around x = 95.0 mol% H 2 O, and this is comparable to that of {[DEME][BF 4 ] + H 2 O} mixtures (x = 96.0 mol% H 2 O).
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Surface deterioration of ammonium acid phthalate crystals
Energy Technology Data Exchange (ETDEWEB)
Barrus, D.M.; Blake, R.L.; Burek, A.J.
1976-01-01
In working with various acid phthalate crystals for low energy X-ray spectroscopy, we have observed a relatively rapid surface degradation of ammonium acid phthalate in comparison with similar crystals was observed. It was found that two different samples degraded in a few days upon exposure to high vacuum (10/sup -6/ - 10/sup -7/ torr). The same crystals showed similar effects when exposed to room atmosphere for two to three weeks. One of these crystals deteriorated while kept constantly in a desiccator jar for about two years. The desiccator environment seems to be the most favorable. The observed difference in the surface of these crystals might be described as a change from a transparent, glasslike condition to a white, powderlike haze somewhat akin to frosted glass. A two week exposure to vacuum for a freshly cleaved crystal caused the integrated coefficient of reflection at 23.6 A to decrease by a factor of 2.5. The degraded surface areas tend to form definite rhombohedral patterns. Since the external symmetry of ammonium acid phthalate crystals is rhombohedral, this suggests that the degradation we observe takes place in the form of large etched figures. A possible mechanism may be sublimation, which would proceed more rapidly in vacuum than in air. It is concluded that ammonium acid phthalate should be kept in a desiccator environment as much as possible. Exposures to vacuum should be brief and critical diffraction measurements should be done using a freshly cleaved surface.
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Effect of plant growth hormones and abiotic stresses on germination ...
African Journals Online (AJOL)
Phosphatases are widely found in plants having intracellular and extracellular activities. Phosphatases are believed to be important for phosphorous scavenging and remobilization in plants, but its role in adaptation to abiotic stresses and growth hormones at germination level has not been critically evaluated. To address ...
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Postoperative Compensatory Ammonium Excretion Subsequent to Systemic Acidosis in Cardiac Patients.
Roehrborn, Friederike; Dohle, Daniel-Sebastian; Waack, Indra N; Tsagakis, Konstantinos; Jakob, Heinz; Teloh, Johanna K
2017-01-01
Postoperative acid-base imbalances, usually acidosis, frequently occur after cardiac surgery. In most cases, the human body, not suffering from any severe preexisting illnesses regarding lung, liver, and kidney, is capable of transient compensation and final correction. The aim of this study was to correlate the appearance of postoperatively occurring acidosis with renal ammonium excretion. Between 07/2014 and 10/2014, a total of 25 consecutive patients scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass were enrolled in this prospective observational study. During the operative procedure and the first two postoperative days, blood gas analyses were carried out and urine samples collected. Urine samples were analyzed for the absolute amount of ammonium. Of all patients, thirteen patients developed acidosis as an initial disturbance in the postoperative period: five of respiratory and eight of metabolic origin. Four patients with respiratory acidosis but none of those with metabolic acidosis subsequently developed a base excess > +2 mEq/L. Ammonium excretion correlated with the increase in base excess. The acidosis origin seems to have a large influence on renal compensation in terms of ammonium excretion and the possibility of an overcorrection.
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Vigna subterranea ammonium transporter gene (VsAMT1: Some bioinformatics insights
Directory of Open Access Journals (Sweden)
Adewole T. Adetunji
2015-12-01
Full Text Available Ammonium transporters (AMTs play a role in the uptake of ammonium, the form in which nitrogen is preferentially absorbed by plants. Vigna subterranea (VsAMT1 and Solanum tuberosum (StAMT1 AMT1s were characterized using molecular biology and bioinformatics methods. AMT1-specific primers were designed and used to amplify the AMT1 internal regions. Nucleotide sequencing, alignment and phylogenetic analysis assigned VsAMT1 and StAMT1 to the AMT1 family. The deduced amino acid sequences showed that VsAMT1 is 92% and 89% similar to Phaseolus vulgaris PvAMT1.1 and Glycine max AMT1 respectively, while StAMT1 is 92% similar to Solanum lycopersicum LeAMT1.1, and correspond to the 5th–10th trans-membrane domains. Residues VsAMT1 D23 and StAMT1 D15 are predicted to be essential for ammonium transport, while mutations of VsAMT1 W1A-L and S87A and StAMT1 S76A may further enhance ammonium transport. In addition to nitrogen uptake from the roots, VsAMT1 may also contribute to interactions with rhizobia.
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Energy Technology Data Exchange (ETDEWEB)
Qiu, Jianghua; Wang, Guanghui; Zeng, Danlin; Tang, Yan [College of Chemical Engineering and Technology, Wuhan University of Science and Technology, Wuhan 430081 (China); Wang, Meng; Li, Yanjun [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)
2009-12-15
Phosphomolybdic acid (HPMo) modified respectively with tetramethyl ammonium chloride (TMAC), dodecyl trimethyl ammonium chloride (DTAC) and hexadecyl trimethyl ammonium chloride (HTAC) as the catalysts were prepared and characterized by FT-IR, XRD and SEM. The catalysts were evaluated for the oxidative desulfurization of benzothiophene (BT), dibenzothiophene (DBT) and straight-run diesel using hydrogen peroxide as an oxidant. Results show that all of the catalysts keep the Keggin structures and are finely dispersed with mixing of quaternary ammonium salts. Hexadecyl chains are more favorable to wrap up DBT to the catalytic center and form stable emulsion system with higher conversion rates of DBT. The shorter dodecyl chains can wrap up BT more suitably and bring smaller steric hindrance, which display higher conversion rates of BT. The oxidative reactions fit apparent first-order kinetics, and the apparent activation energies of DBT are much lower than those of BT. The desulfurization rate of straight-run diesel can be up to 84.4% with the recovery rate of 98.1% catalyzed by [HPMo][HTAC]{sub 2} in 2 h. When increasing the extraction times, the desulfurization rates increase, but the recovery rates of diesel decrease significantly. (author)
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2011-06-14
... antidumping duty order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-856 (Second Review)] Ammonium Nitrate... ammonium nitrate From Russia AGENCY: United States International Trade Commission. ACTION: Notice. SUMMARY...
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Progress and challenges for abiotic stress proteomics of crop plants.
Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar
2013-06-01
Plants are continually challenged to recognize and respond to adverse changes in their environment to avoid detrimental effects on growth and development. Understanding the mechanisms that crop plants employ to resist and tolerate abiotic stress is of considerable interest for designing agriculture breeding strategies to ensure sustainable productivity. The application of proteomics technologies to advance our knowledge in crop plant abiotic stress tolerance has increased dramatically in the past few years as evidenced by the large amount of publications in this area. This is attributed to advances in various technology platforms associated with MS-based techniques as well as the accessibility of proteomics units to a wider plant research community. This review summarizes the work which has been reported for major crop plants and evaluates the findings in context of the approaches that are widely employed with the aim to encourage broadening the strategies used to increase coverage of the proteome. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Ammonium photo-production by heterocytous cyanobacteria: potentials and constraints.
Grizeau, Dominique; Bui, Lan Anh; Dupré, Catherine; Legrand, Jack
2016-08-01
Over the last decades, production of microalgae and cyanobacteria has been developed for several applications, including novel foods, cosmetic ingredients and more recently biofuel. The sustainability of these promising developments can be hindered by some constraints, such as water and nutrient footprints. This review surveys data on N2-fixing cyanobacteria for biomass production and ways to induce and improve the excretion of ammonium within cultures under aerobic conditions. The nitrogenase complex is oxygen sensitive. Nevertheless, nitrogen fixation occurs under oxic conditions due to cyanobacteria-specific characteristics. For instance, in some cyanobacteria, the vegetative cell differentiation in heterocyts provides a well-adapted anaerobic microenvironment for nitrogenase protection. Therefore, cell cultures of oxygenic cyanobacteria have been grown in laboratory and pilot photobioreactors (Dasgupta et al., 2010; Fontes et al., 1987; Moreno et al., 2003; Nayak & Das, 2013). Biomass production under diazotrophic conditions has been shown to be controlled by environmental factors such as light intensity, temperature, aeration rate, and inorganic carbon concentration, also, more specifically, by the concentration of dissolved oxygen in the culture medium. Currently, there is little information regarding the production of extracellular ammonium by heterocytous cyanobacteria. This review compares the available data on maximum ammonium concentrations and analyses the specific rate production in cultures grown as free or immobilized filamentous cyanobacteria. Extracellular production of ammonium could be coupled, as suggested by recent research on non-diazotrophic cyanobacteria, to that of other high value metabolites. There is little information available regarding the possibility for using diazotrophic cyanobacteria as cellular factories may be in regard of the constraints due to nitrogen fixation.
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Zhu, Yan; Ye, Ming; Roeder, Eberhard; Hicks, Richard W.; Shi, Liangsheng; Yang, Jinzhong
2016-01-01
This paper presents a recently developed software, ArcGIS-based Nitrogen Load Estimation Toolkit (ArcNLET), for estimating nitrogen loading from septic systems to surface water bodies. The load estimation is important for managing nitrogen pollution, a world-wide challenge to water resources and environmental management. ArcNLET simulates coupled transport of ammonium and nitrate in both vadose zone and groundwater. This is a unique feature that cannot be found in other ArcGIS-based software for nitrogen modeling. ArcNLET is designed to be flexible for the following four simulating scenarios: (1) nitrate transport alone in groundwater; (2) ammonium and nitrate transport in groundwater; (3) ammonium and nitrate transport in vadose zone; and (4) ammonium and nitrate transport in both vadose zone and groundwater. With this flexibility, ArcNLET can be used as an efficient screening tool in a wide range of management projects related to nitrogen pollution. From the modeling perspective, this paper shows that in areas with high water table (e.g. river and lake shores), it may not be correct to assume a completed nitrification process that converts all ammonium to nitrate in the vadose zone, because observation data can indicate that substantial amount of ammonium enters groundwater. Therefore, in areas with high water table, simulating ammonium transport and estimating ammonium loading, in addition to nitrate transport and loading, are important for avoiding underestimation of nitrogen loading. This is demonstrated in the Eggleston Heights neighborhood in the City of Jacksonville, FL, USA, where monitoring well observations included a well with predominant ammonium concentrations. The ammonium loading given by the calibrated ArcNLET model can be 10-18% of the total nitrogen load, depending on various factors discussed in the paper.
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Maynard, Daniel S; Covey, Kristofer R; Crowther, Thomas W; Sokol, Noah W; Morrison, Eric W; Frey, Serita D; van Diepen, Linda T A; Bradford, Mark A
2018-04-01
Environmental conditions exert strong controls on the activity of saprotrophic microbes, yet abiotic factors often fail to adequately predict wood decomposition rates across broad spatial scales. Given that species interactions can have significant positive and negative effects on wood-decay fungal activity, one possibility is that biotic processes serve as the primary controls on community function, with abiotic controls emerging only after species associations are accounted for. Here we explore this hypothesis in a factorial field warming- and nitrogen-addition experiment by examining relationships among wood decomposition rates, fungal activity, and fungal community structure. We show that functional outcomes and community structure are largely unrelated to abiotic conditions, with microsite and plot-level abiotic variables explaining at most 19% of the total variability in decomposition and fungal activity, and 2% of the variability in richness and evenness. In contrast, taxonomic richness, evenness, and species associations (i.e., co-occurrence patterns) exhibited strong relationships with community function, accounting for 52% of the variation in decomposition rates and 73% in fungal activity. A greater proportion of positive vs. negative species associations in a community was linked to strong declines in decomposition rates and richness. Evenness emerged as a key mediator between richness and function, with highly even communities exhibiting a positive richness-function relationship and uneven communities exhibiting a negative or null response. These results suggest that community-assembly processes and species interactions are important controls on the function of wood-decay fungal communities, ultimately overwhelming substantial differences in abiotic conditions. © 2018 by the Ecological Society of America.
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Effect of Fe3O4 addition on removal of ammonium by zeolite NaA.
Liu, Haibo; Peng, Shuchuan; Shu, Lin; Chen, Tianhu; Bao, Teng; Frost, Ray L
2013-01-15
Magnetic zeolite NaA with different Fe(3)O(4) loadings was prepared by hydrothermal synthesis based on metakaolin and Fe(3)O(4). The effect of added Fe(3)O(4) on the removal of ammonium by zeolite NaA was investigated by varying the Fe(3)O(4) loading, pH, adsorption temperature, initial concentration, adsorption time. Langmuir, Freundlich, and pseudo-second-order modeling were used to describe the nature and mechanism of ammonium ion exchange using both zeolite and magnetic zeolite. Thermodynamic parameters such as change in Gibbs free energy, enthalpy and entropy were calculated. The results show that all the selected factors affect the ammonium ion exchange by zeolite and magnetic zeolite, however, the added Fe(3)O(4) apparently does not affect the ion exchange performance of zeolite to the ammonium ion. Freundlich model provides a better description of the adsorption process than Langmuir model. Moreover, kinetic analysis indicates the exchange of ammonium on the two materials follows a pseudo-second-order model. Thermodynamic analysis makes it clear that the adsorption process of ammonium is spontaneous and exothermic. Regardless of kinetic or thermodynamic analysis, all the results suggest that no considerable effect on the adsorption of the ammonium ion by zeolite is found after the addition of Fe(3)O(4). According to the results, magnetic zeolite NaA can be used for the removal of ammonium due to the good adsorption performance and easy separation method from aqueous solution. Copyright © 2012 Elsevier Inc. All rights reserved.
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A new technique for the synthesis of ammonium phosphomolybdate: precipitation in resin support
International Nuclear Information System (INIS)
Matsuda, H.T.
1977-01-01
A technique for synthesizing ammonium molybdophosphate, an inorganic ion exchanger which retains selectively cesium-137 from a mixture of fission products, employing a strong anionic resin, saturated with molybdate anions, is presented. This method enables the precipitation of ammonium molybdophosphate directly into the resinous structure by adding dihydrogen ammonium phosphate in 7,5M HNO 3 . The reactants maintened at 60 0 C for a period of four hours has been found to be the optimum condition for a maximum yield of this compound (anionic resin-ammonium molybdophosphate = R-AMP). The tests performed for characterizing this compound are: molybdenum-phosphorus ratio determination, electronic absorption spectra, infra-red absorption spectra, reflection microscopy observations, electron probe micro-analysis and X-ray powder patterns. The analysis confirmed the presence of the ammonium molybdophosphate in the resinous structure, permitting, thereby, its use as a cation exchanger. R-AMP showed a capacity of 0,48mE/g of dry material. The cesium retention studies were made using columns charged with R-AMP compound. The behavior of polivalent fission products was studied. The R-AMP column was applied to separate cesium from irradiated uranium solutions [pt
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2013-01-01
Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol. PMID:24107221
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Directory of Open Access Journals (Sweden)
Weijuan Fan
Full Text Available Abiotic stresses are critical delimiters for the increased productivity and cultivation expansion of sweet potato (Ipomoea batatas, a root crop with worldwide importance. The increased production of glycine betaine (GB improves plant tolerance to various abiotic stresses without strong phenotypic changes, providing a feasible approach to improve stable yield production under unfavorable conditions. The gene encoding betaine aldehyde dehydrogenase (BADH is involved in the biosynthesis of GB in plants, and the accumulation of GB by the heterologous overexpression of BADH improves abiotic stress tolerance in plants. This study is to improve sweet potato, a GB accumulator, resistant to multiple abiotic stresses by promoted GB biosynthesis. A chloroplastic BADH gene from Spinacia oleracea (SoBADH was introduced into the sweet potato cultivar Sushu-2 via Agrobacterium-mediated transformation. The overexpression of SoBADH in the transgenic sweet potato improved tolerance to various abiotic stresses, including salt, oxidative stress, and low temperature. The increased BADH activity and GB accumulation in the transgenic plant lines under normal and multiple environmental stresses resulted in increased protection against cell damage through the maintenance of cell membrane integrity, stronger photosynthetic activity, reduced reactive oxygen species (ROS production, and induction or activation of ROS scavenging by the increased activity of free radical-scavenging enzymes. The increased proline accumulation and systemic upregulation of many ROS-scavenging genes in stress-treated transgenic plants also indicated that GB accumulation might stimulate the ROS-scavenging system and proline biosynthesis via an integrative mechanism. This study demonstrates that the enhancement of GB biosynthesis in sweet potato is an effective and feasible approach to improve its tolerance to multiple abiotic stresses without causing phenotypic defects. This strategy for trait
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Directory of Open Access Journals (Sweden)
Lei Wang
2009-01-01
Full Text Available The title compound, ammonium potassium iron(III phosphate fluoride, (NH40.875K0.125FePO4F, is built from zigzag chains ∞1{[FeO4F2]7−}, with Fe3+ in a distorted octahedral coordination, extending along both the [011] and [0overline{1}1] directions. These chains are made up of alternating trans-[FeO4F2] and cis-[FeO4F2] octahedra via shared F-atom corners, and are linked by PO4 tetrahedra, resulting in an open-framework structure with channels along the [010] and [100] directions. There are two crystallographically independent ammonium sites: one in the [010] channels and the other, partially substituted by K+ ions, in the [100] channels. The ammonium in the [010] channels is fixed to the framework via eight hydrogen bonds (six N—H...O and two N—H...F.
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21 CFR 558.340 - Maduramicin ammonium.
2010-04-01
.... Feed continuously as sole ration. Do not feed to laying hens. Withdraw 5 days before slaughter. (2... DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS Specific New Animal Drugs for Use in Animal Feeds § 558.340 Maduramicin ammonium. (a) Approvals. Type A medicated articles: 4.54...
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Near infrared detection of ammonium minerals.
Krohn, M.D.; Altaner, S.P.
1987-01-01
Diagnostic near-infrared spectral features have been identified for minerals with ammonium (NH4+) bound in the crystal structure. Near-infrared detection of NH4-bearing minerals may provide useful information for prospecting for certain ore deposits and may provide a better understanding of the nitrogen cycle within geologic environments.-from Authors
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Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...
African Journals Online (AJOL)
Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate on the ... The test plant was sown in aluminium-polluted soil (conc. ... The perseverance of the test plant in the aluminium spiked soil is an indication of adaptation to the stress ...
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Hazards analyses of hydrogen evolution and ammonium nitrate accumulation in DWPF -- Revision 1
International Nuclear Information System (INIS)
Holtzscheiter, E.W.
1994-01-01
This revision consists of two reports, the first of which is an analysis of potential ammonium nitrate explosion hazards in the DWPF (Defense Waste Processing Facility). Sections describe the effect of impurities (organic and inorganic (chlorides, chromates, metals and oxides)); the consequences of a hydrogen deflagration or detonation; the role of confinement; the action of heat on ammonium nitrate; the thermal decomposition of ammonium nitrate; the hazard of spontaneous heating; and the explosive decomposition of ammonium nitrate. The second report, Hazard analysis of hydrogen evolution in DWPF: Process vessels and vent system for the late wash/nitric acid flowsheet, contains a description of a revised model for hydrogen generation based on the late wash/nitric acid process. The second part of the report is a sensitivity analysis of the base case conditions and the hydrogen generation model
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Yang, Yanwei; Huang, Li; Dong, Yan; Zhang, Hongchen; Zhou, Wei; Ban, Jinghao; Wei, Jingjing; Liu, Yan; Gao, Jing; Chen, Jihua
2014-01-01
Vital pulp preservation in the treatment of deep caries is challenging due to bacterial infection. The objectives of this study were to synthesize a novel, light-cured composite material containing bioactive calcium-silicate (Portland cement, PC) and the antimicrobial quaternary ammonium salt monomer 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB) and to evaluate its effects on Streptococcus mutans growth in vitro. The experimental material was prepared from a 2 : 1 ratio of PC mixed with a resin of 2-hydroxyethylmethacrylate, bisphenol glycerolate dimethacrylate, and triethylene glycol dimethacrylate (4 : 3 : 1) containing 5 wt% MAE-DB. Cured resin containing 5% MAE-DB without PC served as the positive control material, and resin without MAE-DB or PC served as the negative control material. Mineral trioxide aggregate (MTA) and calcium hydroxide (Dycal) served as commercial controls. S. mutans biofilm formation on material surfaces and growth in the culture medium were tested according to colony-forming units (CFUs) and metabolic activity after 24 h incubation over freshly prepared samples or samples aged in water for 6 months. Biofilm formation was also assessed by Live/Dead staining and scanning electron microscopy. S. mutans biofilm formation on the experimental material was significantly inhibited, with CFU counts, metabolic activity, viability staining, and morphology similar to those of biofilms on the positive control material. None of the materials affected bacterial growth in solution. Contact-inhibition of biofilm formation was retained by the aged experimental material. Significant biofilm formation was observed on MTA and Dycal. The synthesized material containing HEMA-BisGMA-TEGDMA resin with MAE-DB as the antimicrobial agent and PC to support mineralized tissue formation inhibited S. mutans biofilm formation even after aging in water for 6 months, but had no inhibitory effect on bacteria in solution. Therefore, this material shows
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Directory of Open Access Journals (Sweden)
Henry D Priest
Full Text Available Brachypodium distachyon is a close relative of many important cereal crops. Abiotic stress tolerance has a significant impact on productivity of agriculturally important food and feedstock crops. Analysis of the transcriptome of Brachypodium after chilling, high-salinity, drought, and heat stresses revealed diverse differential expression of many transcripts. Weighted Gene Co-Expression Network Analysis revealed 22 distinct gene modules with specific profiles of expression under each stress. Promoter analysis implicated short DNA sequences directly upstream of module members in the regulation of 21 of 22 modules. Functional analysis of module members revealed enrichment in functional terms for 10 of 22 network modules. Analysis of condition-specific correlations between differentially expressed gene pairs revealed extensive plasticity in the expression relationships of gene pairs. Photosynthesis, cell cycle, and cell wall expression modules were down-regulated by all abiotic stresses. Modules which were up-regulated by each abiotic stress fell into diverse and unique gene ontology GO categories. This study provides genomics resources and improves our understanding of abiotic stress responses of Brachypodium.
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Directory of Open Access Journals (Sweden)
Asep Bayu Dani Nandiyanto
2016-08-01
Full Text Available The purpose of this study was to investigate influences of temperature on the conversion of ammonium tungstate pentahydrate (ATP powder to tungsten trioxide (WO3 particles with controllable sizes, crystallinities, and physicochemical properties. In this study, we used a simple thermal decomposition method. In the experimental procedure, we explored the effect of temperature on the physicochemical properties of ATP by testing various heating temperatures (from 100 to 900 °C. The heated ATP samples were then characterized by a physical observation (i.e. color and various analysis methods (i.e. a thermal gravimetric and differential thermal analysis, infrared spectroscopy, an X-ray diffraction, and a scanning electron microscope. Experimental results showed that increases in temperature had an impact to the decreases in particle size, the change in material crystallinity, and the change in physical properties (e.g. change of color from white, orange, to yellowish green. The relationships between the reaction temperatures and the physicochemical properties of the ATP were also investigated in detail along with the theoretical consideration and the proposal of the WO3 particle formation mechanism. In simplification, the phenomena can be described into three zones of temperatures. (1 Below 250 °C (release of water molecules and some ammonium ions.; (2 At 250-400 °C (release of water molecules and ammonium ions, restructurization of tungsten and oxygen elements, and formation of amorphous tungsten trioxide. (3 At higher than 400 °C (crystallization of tungsten trioxide. Since ATP possessed reactivity on temperature, its physicochemical properties changing could be observed easily, and the experimental procedure could be done easily. The present study will benefit not only for “chemistry and material science” but also potentially to be used as a model material for explaining the thermal behavior of material to undergraduate students (suitable
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2011-07-07
... duty order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of... Ammonium Nitrate From the Russian Federation; Final Results of the Expedited Sunset Review of Antidumping... review of the suspended antidumping duty investigation on solid fertilizer grade ammonium nitrate...
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2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amides, from ammonium hydroxide... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... subject to reporting. (1) The chemical substance identified as amides, from ammonium hydroxide - maleic...
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Headspace Analysis of Ammonium Nitrate
2017-01-25
explosive ammonium nitrate produces ammonia and nitric acid in the gaseous headspace above bulk solids, but the concentrations of the products have been...and NO2-, a product of nitrate fragmentation (Figure 7). Brief spikes in the background and dips in oxalic acid signal were observed at the time of...either filtered air or experimental nitric acid vapor sources so that analyte signal could be measured directly opposite background. With oxalic
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Conductivity studies of Chitosan doped with different ammonium salts: Effect of ion size
Mohan, C. Raja; Senthilkumar, M.; Jayakumar, K.
2015-06-01
In the present investigation influence of ion size on the electrical properties of various ammonium salts of various concentrations doped with Chitosan liquid electrolyte has been studied. The attachment of ammonium salts with Chitosan has been confirmed through FTIR Spectrum. Polarizability is calculated from the refractive index data. Addition of ammonium salts increases the conductivity. It is also observed that increase in ion size, increases the ionic conductivity due to increase in amorphous nature of the material. Increase in concentration leads to increase in conductivity due to the presence of more number of free ions.
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International Nuclear Information System (INIS)
Gomes, A.S.; Ferreira, A.A.; Coutinho, F.M.B.; Marinho, J.R.D.
1984-01-01
Cerium (IV) salts such as the ceric ammonium nitrate and ceric ammonium sulfate in aqueous acid solution with reducing agents such as alcohols, thiols, glycols, aldehydes and amines are well known initiators of vinyl polymerization. In this work, the polymerization of methyl methacrylate initiated by ceric ammonium nitrate/HNO 3 -poly(ethylene oxide) with hydroxyl end group system was studied in aqueous solution at 25 0 C to obtain block copolymers. (Author) [pt
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Geoelectrical Monitoring of Ammonium Sorption Processes in a Biochar Filtration System
Wang, S. L.; Osei, C.; Rabinovich, A.; Ntarlagiannis, D.; Rouff, A.
2017-12-01
With the rise of modern agriculture, nutrient pollution has become an increasingly important environmental concern. A common problem is excess nitrogen which agricultural livestock farms often generate in the form of ammonium (NH4+). This highly soluble ion is easily transported through runoff and leaching, leading to water supply contamination and soil fertility decline. Biochar is the carbon-rich product of thermal decomposition of biomass in an oxygen-free environment. It is primarily used as a soil enhancer with other applications currently under research. Biochar's unique characteristics such as high surface area, high sorption capacity and long term biological and chemical stability make it a prime candidate for environmental applications such as contaminant regulation and waste effluent treatment. The spectral induced polarization (SIP) method is an established geoelectrical method that has been increasingly used in environmental investigations. SIP is unique among geophysical methods because it is sensitive not only to the bulk properties of the medium under investigation but also to the interfacial properties (e.g., mineral-fluid). The unique properties that make biochar attractive for environmental use are associated with surface properties (e.g., surface area, surface charge, presence of functional groups) that are expected to have a profound effect on SIP signals. This study presents early results on the use of the SIP method to monitor ammonium recycling of swine wastewater in a biochar filtration system. SIP measurements were taken continuously as biochar-packed columns were first injected with an ammonium wastewater solution (sorption phase) and then an ammonium-free solution (desorption phase). Geochemical monitoring showed that outflow ammonium concentration decreased during the sorption phase and increased during the desorption phase. The collected SIP data appear to be in agreement with the geochemical monitoring, providing a temporally
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Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite
International Nuclear Information System (INIS)
Gunawan, Richard; Zhang Dongke
2009-01-01
The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol -1 and 4.55 x 10 7 s -1 without the presence of pyrite and 101.8 kJ mol -1 and 2.57 x 10 9 s -1 with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.
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Thermal stability and kinetics of decomposition of ammonium nitrate in the presence of pyrite.
Gunawan, Richard; Zhang, Dongke
2009-06-15
The interaction between ammonium nitrate based industrial explosives and pyrite-rich minerals in mining operations can lead to the occurrence of spontaneous explosion of the explosives. In an effort to provide a scientific basis for safe applications of industrial explosives in reactive mining grounds containing pyrite, ammonium nitrate decomposition, with and without the presence of pyrite, was studied using a simultaneous Differential Scanning Calorimetry and Thermogravimetric Analyser (DSC-TGA) and a gas-sealed isothermal reactor, respectively. The activation energy and the pre-exponential factor of ammonium nitrate decomposition were determined to be 102.6 kJ mol(-1) and 4.55 x 10(7)s(-1) without the presence of pyrite and 101.8 kJ mol(-1) and 2.57 x 10(9)s(-1) with the presence of pyrite. The kinetics of ammonium nitrate decomposition was then used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of pyrite, based on the Frank-Kamenetskii model of thermal explosion. It was shown that the presence of pyrite reduces the temperature for, and accelerates the rate of, decomposition of ammonium nitrate. It was further shown that pyrite can significantly reduce the critical temperature of ammonium nitrate decomposition, causing undesired premature detonation of the explosives. The critical temperature also decreases with increasing diameter of the blast holes charged with the explosive. The concept of using the critical temperature as indication of the thermal stability of the explosives to evaluate the risk of spontaneous explosion was verified in the gas-sealed isothermal reactor experiments.
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Xiao, Yi; Jiang, Wen; Zhang, Fuzhong
2017-10-20
Responding to nitrogen status is essential for all living organisms. Bacteria have evolved various complex and exquisite regulatory systems to control nitrogen metabolism. However, natural nitrogen regulatory systems, owing to their complexity, often function only in their original hosts and do not respond properly when transferred to another species. By harnessing the Lactococcus GlnRA system, we developed a genetically encoded, cross-species ammonium biosensor that displays a dynamic range up to 9-fold upon detection of ammonium ion. We demonstrated applications of this ammonium biosensor in three different species (Escherichia coli, Pseudomonas putida, and Synechocystis sp.) to detect different nitrogen sources. This ammonium sensor was further used to regulate the biosynthesis of a nitrogen-rich polymer, cyanophycin, based on ammonium concentration. Given the importance of nitrogen responses, the developed biosensor should be broadly applicable to synthetic biology and bioengineering.
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Cell biology of anaerobic ammonium-oxidizing bacteria
Niftrik, L.A.M.P. van
2008-01-01
Anammox bacteria perform anaerobic ammonium oxidation to dinitrogen gas and belong to the phylum Planctomycetes. Whereas most Prokaryotes consist of one compartment, the cytoplasm bounded by the cytoplasmic membrane and cell wall, the species within this phylum are compartmentalized by intracellular
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Directory of Open Access Journals (Sweden)
Sung-Je Yoo
2017-06-01
Full Text Available Recently, global warming and drastic climate change are the greatest threat to the world. The climate change can affect plant productivity by reducing plant adaptation to diverse environments including frequent high temperature; worsen drought condition and increased pathogen transmission and infection. Plants have to survive in this condition with a variety of biotic (pathogen/pest attack and abiotic stress (salt, high/low temperature, drought. Plants can interact with beneficial microbes including plant growth-promoting rhizobacteria, which help plant mitigate biotic and abiotic stress. This overview presents that rhizobacteria plays an important role in induced systemic resistance (ISR to biotic stress or induced systemic tolerance (IST to abiotic stress condition; bacterial determinants related to ISR and/or IST. In addition, we describe effects of rhizobacteria on defense/tolerance related signal pathway in plants. We also review recent information including plant resistance or tolerance against multiple stresses (bioticabiotic. We desire that this review contribute to expand understanding and knowledge on the microbial application in a constantly varying agroecosystem, and suggest beneficial microbes as one of alternative environment-friendly application to alleviate multiple stresses.
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Directory of Open Access Journals (Sweden)
Shalini Tiwari
2017-08-01
Full Text Available Being sessile in nature, plants have to withstand various adverse environmental stress conditions including both biotic and abiotic stresses. Comparatively, abiotic stresses such as drought, salinity, high temperature, and cold pose major threat to agriculture by negatively impacting plant growth and yield worldwide. Rice is one of the most widely consumed staple cereals across the globe, the production and productivity of which is also severely affected by different abiotic stresses. Therefore, several crop improvement programs are directed toward developing stress tolerant rice cultivars either through marker assisted breeding or transgenic technology. Alternatively, some known rhizospheric competent bacteria are also known to improve plant growth during abiotic stresses. A plant growth promoting rhizobacteria (PGPR, Bacillus amyloliquefaciens NBRI-SN13 (SN13 was previously reported by our lab to confer salt stress tolerance to rice seedlings. However, the present study investigates the role of SN13 in ameliorating various abiotic stresses such as salt, drought, desiccation, heat, cold, and freezing on a popular rice cv. Saryu-52 under hydroponic growth conditions. Apart from this, seedlings were also exogenously supplied with abscisic acid (ABA, salicylic acid (SA, jasmonic acid (JA and ethephon (ET to study the role of SN13 in phytohormone-induced stress tolerance as well as its role in abiotic and biotic stress cross-talk. All abiotic stresses and phytohormone treatments significantly affected various physiological and biochemical parameters like membrane integrity and osmolyte accumulation. SN13 also positively modulated stress-responsive gene expressions under various abiotic stresses and phytohormone treatments suggesting its multifaceted role in cross-talk among stresses and phytohormones in response to PGPR. To the best of our knowledge, this is the first report on detailed analysis of plant growth promotion and stress alleviation by a
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Deppe, Marianna; Well, Reinhard; Giesemann, Anette; Flessa, Heinz
2016-04-01
High concentrations of ammonium as they occur, e.g., after point-injection of ammonium fertilizer solution according to the CULTAN fertilization technique may retard nitrification. Potential advantages in comparison to conventional fertilization include a higher N efficiency of crops, reduced nitrate leaching, and lower N2O and N2 emissions. Dynamics of nitrification due to plant uptake and dilution processes, leading to decreasing ammonium concentrations in fertilizer depots, has only poorly been studied before. Furthermore, there is little information about the relative contribution of different N2O production processes under these conditions. To elucidate the process dynamics a laboratory incubation study was conducted. After fertilization with ammonium sulfate at 5 levels (from 0 to 5000 mg NH4+-N kg-1; 20mg NO3--N kg-1 each), sandy loam soil was incubated in dynamic soil microcosms for 21 days. N2O, CH4 and CO2 fluxes as well as isotope signatures of N2O and, at three dates, NO3- and NH4+ were measured. To identify N2O production processes, acetylene inhibition (0.01 vol.%), 15N tracer approaches, and isotopomer data (15N site preference and δ18O) were used. N2O emissions were highest at 450mg NH4+-N kg-1 and declined with further increasing concentrations. At 5000 mg NH4+-N kg-1 nitrification was completely inhibited. However, approximately 90% of N2O production was inhibited by acetylene application, and there was no change in the relative contribution of nitrification and denitrification to N2O production with N level. Applying the non-equilibrium technique to our 15N tracer data revealed heterogeneous distribution of denitrification in soil, with at least two distinct NO3- pools, and spatial separation of NO3- formation and consumption. In comparison with the acetylene inhibition and 15N tracer approaches the results of the isotopomer approach were reasonable and indicated substantial contribution of nitrifier-denitrification (10-40%) to total N2O
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The Comparison of Ammonium or Nitrate-Grown Lettuce and Spinach in a Hydroponic System
H. R. Roosta
2010-01-01
Most plant species are sensitive to high ammonium concentrations. In this experiment the sensitivity of lettuce and spinach to ammonium was investigated. In a factorial experiment with framework of a completely randomized design with two factors, nitrogen form (ammonium and nitrate) and plant species (lettuce and spinach), and three replications seeds were germinated in a mixture of perlite, sand and clay in soil-maid pots. After two weeks, the seedlings at two true-leaf stage were then trans...
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Alkali metal and ammonium chlorides in water and heavy water (binary systems)
Cohen-Adad, R
1991-01-01
This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.
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International Nuclear Information System (INIS)
Wei Zaishan; Lin Zhehang; Niu Hejingying; He Haiming; Ji Yongfeng
2009-01-01
Microwave reactor with ammonium bicarbonate (NH 4 HCO 3 ) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) from flue gas. The results showed that the microwave reactor filled with NH 4 HCO 3 and zeolite could reduce SO 2 to sulfur with the best desulfurization efficiency of 99.1% and reduce NO x to nitrogen with the best NO x purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO x concentration has little effect on denitrification but has no influence on desulfurization, SO 2 concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO 2 , NO x and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent
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Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals
Abiotic degradation of chlorinated solvents by reactive iron minerals such as iron sulfides, magnetite, green rust, and other Fe(II)-containing minerals has been observed in both laboratory and field conditions. These reactive iron minerals typically form under iron and sulfate ...
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Aluminium, extractable from soil samples by the acid ammonium acetate soil-testing method
Directory of Open Access Journals (Sweden)
Osmo Mäkitie
1968-05-01
Full Text Available The extractant, 0.5 M acetic acid –0.5 M ammonium acetate at pH 4.65, which is used in soil-testing, extracts relatively high amounts of aluminium from acid soils. The mean values of acetate-extractable aluminium at pH 4.65, 1.75 meq Al/100 g of soil, and of exchangeable aluminium (M KCI extraction, 0.41 meq Al were obtained from a material of 30 samples of acid soils (Table 2. Several other acetic acid ammonium acetate extractants, from M acetic acid to M ammonium acetate solution were also used for studying the extractability of soil aluminium. The soil-testing extractant can be used for the estimation of the soluble amounts of aluminium in acid soils, however, further studies are needed for a better interpretation of the ammonium acetate extractable (at pH 4.65 aluminium in our soils.
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Alcohol dehydrogenase 1 (ADH1) confers both abiotic and biotic stress resistance in Arabidopsis.
Shi, Haitao; Liu, Wen; Yao, Yue; Wei, Yunxie; Chan, Zhulong
2017-09-01
Although the transcriptional regulation and upstream transcription factors of AtADH1 in response to abiotic stress are widely revealed, the in vivo roles of AtADH1 remain unknown. In this study, we found that the expression of AtADH1 was largely induced after salt, drought, cold and pathogen infection. Further studies found that AtADH1 overexpressing plants were more sensitive to abscisic acid (ABA) in comparison to wide type (WT), while AtADH1 knockout mutants showed no significant difference compared with WT in ABA sensitivity. Consistently, AtADH1 overexpressing plants showed improved stress resistance to salt, drought, cold and pathogen infection than WT, but the AtADH1 knockout mutants had no significant difference in abiotic and biotic stress resistance. Moreover, overexpression of AtADH1 expression increased the transcript levels of multiple stress-related genes, accumulation of soluble sugars and callose depositions. All these results indicate that AtADH1 confers enhanced resistance to both abiotic and biotic stresses. Copyright © 2017 Elsevier B.V. All rights reserved.
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21 CFR 184.1135 - Ammonium bicarbonate.
2010-04-01
... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium bicarbonate. 184.1135 Section 184.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 18...
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21 CFR 184.1133 - Ammonium alginate.
2010-04-01
...: Category of food Maximum level of use in food (as served) (percent) Functional use Confections, frostings... chapter 0.4 Do. Sweet sauces, § 170.3(n)(43) of this chapter 0.5 Do. All other food categories 0.1... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium alginate. 184.1133 Section 184.1133 Food...
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Directory of Open Access Journals (Sweden)
Balaji eM
2015-12-01
Full Text Available Tetraspanin family is comprised of evolutionarily conserved integral membrane proteins. The incredible ability of tetraspanins to form ‘micro domain complexes’ and their preferential targeting to membranes emphasizes their active association with signal recognition and communication with neighboring cells, thus acting as key modulators of signaling cascades. In animals, tetraspanins are associated with multitude of cellular processes. Unlike animals, the biological relevance of tetraspanins in plants has not been well investigated. In Arabidopsis tetraspanins are known to contribute in important plant development processes such as leaf morphogenesis, root and floral organ formation. In the present study we investigated the genomic organization, chromosomal distribution, phylogeny and domain structure of 15 rice tetraspanin proteins (OsTETs. OsTET proteins had similar domain structure and signature ‘GCCK/R’ motif as reported in Arabidopsis. Comprehensive expression profiling of OsTET genes suggested their possible involvement during rice development. While OsTET9 and 10 accumulated predominantly in flowers, OsTET5, 8 and 12 were preferentially expressed in root tissues. Noticeably, seven OsTETs exhibited more than 2-fold up regulation at early stages of flag leaf senescence in rice. Furthermore, several OsTETs were differentially regulated in rice seedlings exposed to abiotic stresses, exogenous treatment of hormones and nutrient deprivation. Transient subcellular localization studies of eight OsTET proteins in tobacco epidermal cells showed that these proteins localized in plasma membrane. The present study provides valuable insights into the possible roles of tetraspanins in regulating development and defining response to abiotic stresses in rice. Targeted proteomic studies would be useful in identification of their interacting partners under different conditions and ultimately their biological function in plants
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Darin J. Law; Deborah M. Finch
2011-01-01
Plant water use in drylands can be complex due to variation in hydrologic, abiotic and biotic factors, particularly near ephemeral or intermittent streams. Plant use of groundwater may be important but is usually uncertain. Disturbances like fire contribute to complex spatiotemporal heterogeneity. Improved understanding of how such hydrologic, abiotic, and biotic...
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Regulation of Translation Initiation under Biotic and Abiotic Stresses
Directory of Open Access Journals (Sweden)
Ana B. Castro-Sanz
2013-02-01
Full Text Available Plants have developed versatile strategies to deal with the great variety of challenging conditions they are exposed to. Among them, the regulation of translation is a common target to finely modulate gene expression both under biotic and abiotic stress situations. Upon environmental challenges, translation is regulated to reduce the consumption of energy and to selectively synthesize proteins involved in the proper establishment of the tolerance response. In the case of viral infections, the situation is more complex, as viruses have evolved unconventional mechanisms to regulate translation in order to ensure the production of the viral encoded proteins using the plant machinery. Although the final purpose is different, in some cases, both plants and viruses share common mechanisms to modulate translation. In others, the mechanisms leading to the control of translation are viral- or stress-specific. In this paper, we review the different mechanisms involved in the regulation of translation initiation under virus infection and under environmental stress in plants. In addition, we describe the main features within the viral RNAs and the cellular mRNAs that promote their selective translation in plants undergoing biotic and abiotic stress situations.
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Fukushi, Keiichi; Ito, Hideyuki; Kimura, Kenichi; Yokota, Kuriko; Saito, Keiitsu; Chayama, Kenji; Takeda, Sahori; Wakida, Shin-ichi
2006-02-17
We developed capillary zone electrophoresis (CZE) with direct UV detection for determination of ammonium in environmental water samples. Ammonium in the samples was partly converted into ammonia in the alkaline background electrolyte (BGE) during migration and was detected by molecular absorption of ammonia at 190 nm in approximately 7 min. The limit of detection (LOD) for ammonium was 0.24 mg/l (as nitrogen) at a signal-to-noise ratio of three. The respective values of the relative standard deviation (RSD) of peak area, peak height, and migration time for ammonium were 2.1, 1.8, and 0.46%. Major alkali and alkaline earth metal ions coexisting in the samples did not interfere with ammonium determination by the proposed method. The proposed method determined ammonium in surface water and sewage samples. The results were compared to those obtained using ion chromatography (IC).
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Effects of meat juice on biofilm formation of Campylobacter and Salmonella.
Li, Jiaqi; Feng, Jinsong; Ma, Lina; de la Fuente Núñez, César; Gölz, Greta; Lu, Xiaonan
2017-07-17
Campylobacter and Salmonella are leading causes of foodborne illnesses worldwide, vastly harboured by raw meat as their common food reservoir. Both microbes are prevalent in meat processing environments in the form of biofilms that contribute to cross-contamination and foodborne infection. This study applied raw meat juice (chicken juice and pork juice) as a minimally processed food model to study its effects on bacterial biofilm formation. Meat juice was collected during the freeze-thaw process of raw meat and sterilized by filtration. In 96-well polystyrene plates and glass chambers, supplementation of over 25% meat juice (v/v) in laboratory media led to an increase in biofilm formation of Campylobacter and Salmonella. During the initial attachment stage of biofilm development, more bacterial cells were present on surfaces treated with meat juice residues compared to control surfaces. Meat juice particulates on abiotic surfaces facilitated biofilm formation of Campylobacter and Salmonella under both static and flow conditions, with the latter being assessed using a microfluidic platform. Further, the deficiency in biofilm formation of selected Campylobacter and Salmonella mutant strains was restored in the presence of meat juice particulates. These results suggested that meat juice residues on the abiotic surfaces might act as a surface conditioner to support initial attachment and biofilm formation of Campylobacter and Salmonella. This study sheds light on a possible survival mechanism of Campylobacter and Salmonella in meat processing environments, and indicates that thorough cleaning of meat residues during meat production and handling is critical to reduce the bacterial load of Campylobacter and Salmonella. Copyright © 2017 Elsevier B.V. All rights reserved.
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Chen, Hao; Xiong, Liming
2011-01-01
has emerged as an important player in gene regulation and is involved in many aspects of plant development, including lateral root formation. In a recent study, we found that FIERY1, a bifunctional abiotic stress and abscisic acid (ABA) signaling
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ATP Supply May Contribute to Light-Enhanced Calcification in Corals More Than Abiotic Mechanisms
Directory of Open Access Journals (Sweden)
Giovanni Galli
2018-03-01
Full Text Available Zooxanthellate corals are known to increase calcification rates when exposed to light, a phenomenon called light-enhanced calcification that is believed to be mediated by symbionts' photosynthetic activity. There is controversy over the mechanism behind this phenomenon, with hypotheses coarsely divided between abiotic and biologically-mediated mechanisms. At the same time, accumulating evidence shows that calcification in corals relies on active ion transport to deliver the skeleton building blocks into the calcifying medium, making it is an energetically costly activity. Here we build on generally accepted conceptual models of the coral calcification machinery and conceptual models of the energetics of coral-zooxanthellae symbiosis to develop a model that can be used to isolate the biologically-mediated and abiotic effects of photosynthesis, respiration, temperature, and seawater chemistry on coral calcification rates and related metabolic costs. We tested this model on data from the Mediterranean scleractinian Cladocora caespitosa, an acidification resistant species. We concluded that most of the variation in calcification rates due to photosynthesis, respiration and temperature can be attributed to biologically-mediated mechanisms, in particular to the ATP supplied to the active ion transports. Abiotic effects are also present but are of smaller magnitude. Instead, the decrease in calcification rates caused by acidification, albeit small, is sustained by both abiotic and biologically-mediated mechanisms. However, there is a substantial extra cost of calcification under acidified conditions. Based on these findings and on a literature review we suggest that the energy aspect of coral calcification might have been so far underappreciated.
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Latifah, O.; Ahmed, O. H.; Abdul Majid, N. M.
2017-12-01
Form of nitrogen present in soils is one of the factors that affect nitrogen loss. Nitrate is mobile in soils because it does not absorb on soil colloids, thus, causing it to be leached by rainfall to deeper soil layers or into the ground water. On the other hand, temporary retention and timely release of ammonium in soils regulate nitrogen availability for crops. In this study, composted paddy husk was used in studies of soil leaching, buffering capacity, and ammonium adsorption and desorption to determine the: (i) availability of exchangeable ammonium, available nitrate, and total nitrogen in an acid soil after leaching the soil for 30 days, (ii) soil buffering capacity, and (iii) ability of the composted paddy husk to adsorb and desorb ammonium from urea. Leaching of ammonium and nitrate were lower in all treatments with urea and composted paddy husk compared with urea alone. Higher retention of soil exchangeable ammonium, available nitrate, and total nitrogen of the soils with composted paddy husk were due to the high buffering capacity and cation exchange capacity of the amendment to adsorb ammonium thus, improving nitrogen availability through temporary retention on the exchange sites of the humic acids of the composted paddy husk. Nitrogen availability can be enhanced if urea is amended with composted paddy husk.
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Institute of Scientific and Technical Information of China (English)
TAYLOR Shauna M; HE Yiliang; ZHAO Bin; HUANG Jue
2009-01-01
Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further analyze its removal ability, several experiments were conducted to identify the growth and ammonium removal response in different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30℃, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth. The nitrification products hydroxylamine (NH2OH), nitrite (NO2-) and nitrate (NO3-) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.
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Microarray meta-analysis to explore abiotic stress-specific gene expression patterns in Arabidopsis.
Shen, Po-Chih; Hour, Ai-Ling; Liu, Li-Yu Daisy
2017-12-01
Abiotic stresses are the major limiting factors that affect plant growth, development, yield and final quality. Deciphering the underlying mechanisms of plants' adaptations to stresses using few datasets might overlook the different aspects of stress tolerance in plants, which might be simultaneously and consequently operated in the system. Fortunately, the accumulated microarray expression data offer an opportunity to infer abiotic stress-specific gene expression patterns through meta-analysis. In this study, we propose to combine microarray gene expression data under control, cold, drought, heat, and salt conditions and determined modules (gene sets) of genes highly associated with each other according to the observed expression data. By analyzing the expression variations of the Eigen genes from different conditions, we had identified two, three, and five gene modules as cold-, heat-, and salt-specific modules, respectively. Most of the cold- or heat-specific modules were differentially expressed to a particular degree in shoot samples, while most of the salt-specific modules were differentially expressed to a particular degree in root samples. A gene ontology (GO) analysis on the stress-specific modules suggested that the gene modules exclusively enriched stress-related GO terms and that different genes under the same GO terms may be alternatively disturbed in different conditions. The gene regulatory events for two genes, DREB1A and DEAR1, in the cold-specific gene module had also been validated, as evidenced through the literature search. Our protocols study the specificity of the gene modules that were specifically activated under a particular type of abiotic stress. The biplot can also assist to visualize the stress-specific gene modules. In conclusion, our approach has the potential to further elucidate mechanisms in plants and beneficial for future experiments design under different abiotic stresses.
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Influence of nitrogen dioxide on the thermal decomposition of ammonium nitrate
Igor L. Kovalenko
2015-01-01
In this paper results of experimental studies of ammonium nitrate thermal decomposition in an open system under normal conditions and in NO2 atmosphere are presented. It is shown that nitrogen dioxide is the initiator of ammonium nitrate self-accelerating exothermic cyclic decomposition process. The insertion of NO2 from outside under the conditions of nonisothermal experiment reduces the characteristic temperature of the beginning of self-accelerating decomposition by 50...70 °C. Using metho...
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Chen Zhixiang; Xiao Yong; Shi Junwei; Lai Zhibing; Chen Han; Xu Xinping
2010-01-01
Abstract Background WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. Results We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple muta...
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Konermann, Lars
2017-09-01
Native ESI-MS involves the transfer of intact proteins and biomolecular complexes from solution into the gas phase. One potential pitfall is the occurrence of pH-induced changes that can affect the analyte while it is still surrounded by solvent. Most native ESI-MS studies employ neutral aqueous ammonium acetate solutions. It is a widely perpetuated misconception that ammonium acetate buffers the analyte solution at neutral pH. By definition, a buffer consists of a weak acid and its conjugate weak base. The buffering range covers the weak acid pKa ± 1 pH unit. NH4 + and CH3-COO- are not a conjugate acid/base pair, which means that they do not constitute a buffer at pH 7. Dissolution of ammonium acetate salt in water results in pH 7, but this pH is highly labile. Ammonium acetate does provide buffering around pH 4.75 (the pKa of acetic acid) and around pH 9.25 (the pKa of ammonium). This implies that neutral ammonium acetate solutions electrosprayed in positive ion mode will likely undergo acidification down to pH 4.75 ± 1 in the ESI plume. Ammonium acetate nonetheless remains a useful additive for native ESI-MS. It is a volatile electrolyte that can mimic the solvation properties experienced by proteins under physiological conditions. Also, a drop from pH 7 to around pH 4.75 is less dramatic than the acidification that would take place in pure water. It is hoped that the habit of referring to pH 7 solutions as ammonium acetate "buffer" will disappear from the literature. Ammonium acetate "solution" should be used instead. [Figure not available: see fulltext.
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Directory of Open Access Journals (Sweden)
Aude Deschuyteneer
Full Text Available Proteins of the conserved Mep-Amt-Rh family, including mammalian Rhesus factors, mediate transmembrane ammonium transport. Ammonium is an important nitrogen source for the biosynthesis of amino acids but is also a metabolic waste product. Its disposal in urine plays a critical role in the regulation of the acid/base homeostasis, especially with an acid diet, a trait of Western countries. Ammonium accumulation above a certain concentration is however pathologic, the cytotoxicity causing fatal cerebral paralysis in acute cases. Alteration in ammonium transport via human Rh proteins could have clinical outcomes. We used a yeast-based expression assay to characterize human Rh variants resulting from non synonymous single nucleotide polymorphisms (nsSNPs with known or unknown clinical phenotypes and assessed their ammonium transport efficiency, protein level, localization and potential trans-dominant impact. The HsRhAG variants (I61R, F65S associated to overhydrated hereditary stomatocytosis (OHSt, a disease affecting erythrocytes, proved affected in intrinsic bidirectional ammonium transport. Moreover, this study reveals that the R202C variant of HsRhCG, the orthologue of mouse MmRhcg required for optimal urinary ammonium excretion and blood pH control, shows an impaired inherent ammonium transport activity. Urinary ammonium excretion was RHcg gene-dose dependent in mouse, highlighting MmRhcg as a limiting factor. HsRhCG(R202C may confer susceptibility to disorders leading to metabolic acidosis for instance. Finally, the analogous R211C mutation in the yeast ScMep2 homologue also impaired intrinsic activity consistent with a conserved functional role of the preserved arginine residue. The yeast expression assay used here constitutes an inexpensive, fast and easy tool to screen nsSNPs reported by high throughput sequencing or individual cases for functional alterations in Rh factors revealing potential causal variants.
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Borojovich, Eitan J C; Münster, Meshulam; Rafailov, Gennady; Porat, Ze'ev
2010-07-01
Precipitation of struvite (MgNH4PO4) is a known process for purification of wastewater from high concentrations of ammonium. The optimal conditions for precipitation are basic pH (around 9) and sufficient concentrations of magnesium and phosphate ions. In this work, we accomplished efficient precipitation of ammonium from concentrated industrial waste stream by using magnesium oxide (MgO) both as a source of magnesium ions and as a base. Best results were obtained with technical-grade MgO, which provided 99% removal of ammonium. Moreover, ammonium removal occurred already at pH 7, and the residual ammonium concentration (50 mg/L) remained constant upon addition of more MgO without rising again, as occurs with sodium hydroxide (NaOH). This process may have two other advantages; it also can be relevant for the problem of uncontrolled precipitation of struvite in the supernatant of anaerobic sludge treatment plants, and the precipitate can be used as a fertilizer.
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International Nuclear Information System (INIS)
Lachowicz, T.M.; Oblak, E.; Piatkowski, J.
1992-01-01
In previous studies we have observed that auxotrophic mutants of yeast were much more sensitive to quaternary ammonium salts than the corresponding isogenic wild type strains. The super sensitivity of the auxotrophs seems to be a characteristic feature of yeast and yeast-like microorganisms: the level of sensitivity of the quaternary ammonium salts of the bacterial auxotrophs and their original prototrophic forms appeared to be the same. The super sensitivity of yeast auxotrophs disappeared on minimal media with ammonium as a nitrogen source. In this report there are presented the data indicating that enrichment of the minimal medium with arginine restores the super sensitivity of auxotrophic yeast mutants to the quaternary ammonium salts. The results of amino-acid transport into the auxotrophic yeast cells treated with a quaternary ammonium salt in the presence and absence of arginine are given. A working hypothesis of the mechanism of these salts action as a specific inhibition of nutrient transport is discussed. (author). 19 refs, 3 figs, 8 figs
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Chemical treatment of ammonium fluoride solution in uranium reconversion plant
International Nuclear Information System (INIS)
Carvalho Frajndlich, E.U. de.
1992-01-01
A chemical procedure is described for the treatment of the filtrate, produced from the transformation of uranium hexafluoride (U F 6 ) into ammonium uranyl carbonate (AUC). This filtrate is an intermediate product in the U F 6 to uranium dioxide (U O 2 ) reconversion process. The described procedure recovers uranium as ammonium peroxide fluoro uranate (APOFU) by precipitation with hydrogen peroxide (H 2 O 2 ), and as later step, its calcium fluoride (CaF 2 ) co-precipitation. The recovered uranium is recycled to the AUC production plant. (author)
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Single-crystal neutron diffraction study of ammonium nitrate phase III
International Nuclear Information System (INIS)
Choi, C.S.; Prask, H.J.
1982-01-01
The crystal structure of ammonium nitrate phase III has been studied at room temperature by neutron diffraction using a single crystal containing 5% KNO 3 in solid-solution form. The space group is Pnma, with a = 7.6772 (4), b = 5.8208 (4), c = 7.1396 (5) A, Z = 4. The final residual after full-matrix least-squares refinement was R = 0.042 for 348 observed reflections. The ammonium ions are thermally disordered into two orientations, displaced by an angle of approximately 42 0 about an axis parallel to the c axis. (Auth.)
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International Nuclear Information System (INIS)
Murphy, A.T.
1984-10-01
A brief review of the literature on the effects of nitrate and ammonium nitrogen sources on plant growth, and the assimilation of those nitrogen sources, has been presented. It was concluded that ammonium nutrition produces optimum growth, with nitrate + ammonium being a better nitrogen source than only nitrate. Leaf blade nitrate reductase activity exceeded that of the root in nitrate-fed plants, suggesting that the shoot is the major region of nitrate assimilation. This is further supported by the results of xylem exudate analysis, where 93% of the newly-absorbed nitrogen exported by the roots was detected as nitrate. Evidence in support of this hypothesis was also obtained by studying the distribution of 15 N in the various nitrogenous compounds. The effects of nitrogen source on plant growth, organic nitrogen and inorganic nitrogen contents, and the rates of incorporation into nitrogenous compounds were studied. The observed differences were explained with reference to the effects of the various nitrogen sources on the physiology of the plants. The experimental techniques included assays of the enzymes nitrate reductase and glutamine synthetase, whole plant growth studies, and the analysis of nitrogenous compounds of xylem exudate and those extracted from the leaf blade, leaf base, and root regions of maize plants after feeding with a nutrient solution containing nitrogen as 15 N
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Assessment of derelict soil quality: Abiotic, biotic and functional approaches.
Vincent, Quentin; Auclerc, Apolline; Beguiristain, Thierry; Leyval, Corinne
2018-02-01
The intensification and subsequent closing down of industrial activities during the last century has left behind large surfaces of derelict lands. Derelict soils have low fertility, can be contaminated, and many of them remain unused. However, with the increasing demand of soil surfaces, they might be considered as a resource, for example for non-food biomass production. The study of their physico-chemical properties and of their biodiversity and biological activity may provide indications for their potential re-use. The objective of our study was to investigate the quality of six derelict soils, considering abiotic, biotic, and functional parameters. We studied (i) the soil bacteria, fungi, meso- and macro-fauna and plant communities of six different derelict soils (two from coking plants, one from a settling pond, two constructed ones made from different substrates and remediated soil, and an inert waste storage one), and (ii) their decomposition function based on the decomposer trophic network, enzyme activities, mineralization activity, and organic pollutant degradation. Biodiversity levels in these soils were high, but all biotic parameters, except the mycorrhizal colonization level, discriminated them. Multivariate analysis showed that biotic parameters co-varied more with fertility proxies than with soil contamination parameters. Similarly, functional parameters significantly co-varied with abiotic parameters. Among functional parameters, macro-decomposer proportion, enzyme activity, average mineralization capacity, and microbial polycyclic aromatic hydrocarbon degraders were useful to discriminate the soils. We assessed their quality by combining abiotic, biotic, and functional parameters: the compost-amended constructed soil displayed the highest quality, while the settling pond soil and the contaminated constructed soil displayed the lowest. Although differences among the soils were highlighted, this study shows that derelict soils may provide a
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Cloning and expression analysis of a novel ammonium transporter gene from eichhornia
International Nuclear Information System (INIS)
Li, Y.; Yan, G.; Zheng, L.
2014-01-01
In order to explore the molecular mechanism for Eichhornia crassipes to transport ammonium from outside, we cloned a novel ammonium transporter (EcAMT) gene from E. crassipes and identified its function by using yeast complementation experiment. The full-length cDNA of EcAMT contains a 1506 nucletide-long open reading frame which encodes a protein of 501 amino acids. Bioinformatics analysis predicted that EcAMT had 8 transmembrane regions. The expressions of EcAMT gene under three different nitrogen conditions were evaluated by quantitative reverse transcriptase PCR (qRT-PCR) and the results showed that the expression of EcAMT gene was up-regulated under nitrogen starvation. Our study results revealed some molecular mechanism of E. crassipes to absorb the ammonium in eutrophic water. (author)
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Nitrogen concentrations in a small Mediterranean stream: 1. Nitrate 2. Ammonium
Directory of Open Access Journals (Sweden)
A. Butturini
2002-01-01
Full Text Available The importance of storm frequency as well as the groundwater and hyporheic inputs on nitrate (NO3-N and ammonium (NH4-N levels in stream water were studied in a small perennial Mediterranean catchment, Riera Major, in northeast Spain. NO3-N concentrations ranged from 0.15 to 1.9 mg l-1. Discharge explained 47% of the annual NO3-N concentration variance, but this percentage increased to 97% when single floods were analysed. The rate of change in nitrate concentration with respect to flow, ΔNO3-N/ΔQ, ranged widely from 0 to 20 μg NO3-N s l-2. The ΔNO3-N/ΔQ values fitted to a non linear model with respect to the storm flow magnitude (ΔQ (r2=0.48, d.f.=22, P3-N/ΔQ occurred at intermediate ΔQ values, whereas low ΔNO3-N/ΔQ values occurred during severe storms (ΔQ > 400 l s-1. N3-N concentrations exhibit anticlockwise hysteresis patterns with changing flow and the patterns observed for autumnal and winter storms indicated that groundwater was the main N3-N source for stream and hyporheic water. At baseflow, NO3-N concentration in groundwater was higher (t=4.75, d.f.=29, P>0.001 and co-varied with concentrations in the stream (r=0.91, d.f.=28, P3-N concentration in hyporheic water was identical to that in stream water. The role of the hyporheic zone as source or sink for ammonium was studied hyporheic was studied comparing its concentrations in stream and hyporheic zone before and after a major storm occurred in October 1994 that removed particulate organic matter stored in sediments. Results showed high ammonium concentrations (75±28 s.d. μg NH4-N l-1 before the storm flow in the hyporheic zone. After the storm, the ammonium concentration in the hyporheic dropped by 80% (13.6±8 μg N4-N l-1 and approached to the level found in stream water (11±8 μg NH4-N l-1 indicating that indisturbed hyporheic sediments act as a source for ammonium. After the storm, the ammonium concentrations in the stream, hyporheic and groundwater zones were very
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Pilot scale for preparation of ammonium uranyl carbonate
International Nuclear Information System (INIS)
Santos, L.R. dos.
1989-01-01
The procedure adopted for obtaining Ammonium Uranyl Carbonate (AUC) from uranium hexafluoride (UF sub(6)) or aqueous solutions of uranylnitrate (UO sub(2)(NO sub(3)) sub(2)) is described in the present work. This procedure involves the precipitation of AUC in a chemical reactor by the addition of gaseous UF sub(6) or solutions of uranylnitrate to NH sub(3) and CO sub(2) gases in a solution containing ammonium bicarbonate, where pH and temperature are controlled. Details regarding the characterization and quality control methods in the preparation of AUC are presented along with their physical and chemical properties. Some informations about effluents generated during the process are presented too. An attempt is made to correlate the parameters involved in the precipitation process of AUC and their characteristics. (author)
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2012-10-24
... antidumping duty order on ammonium nitrate from Ukraine would be likely to lead to continuation or recurrence... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-894 (Second Review)] Ammonium Nitrate... Full Five-year Review Concerning the Antidumping Duty Order on Ammonium Nitrate From Ukraine AGENCY...
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Quaternary ammonium compounds – New occupational hazards
Directory of Open Access Journals (Sweden)
Agnieszka Lipińska-Ojrzanowska
2014-10-01
Full Text Available Quaternary ammonium compounds (QACs, quats belong to organic ionic chemical agents which display unique properties of both surfactants and disinfectants. Their wide distribution in the work environment and also in private households brings about new occupational hazards. This paper reviews reports about the health effects of QACs. QACs could play a role of sensitizers and irritants to the skin and mucous membranes. It is suspected that particular QACs can display an immunologic crossreactivity between each other and with other chemical compounds containing ammonium ion, such as muscle relaxants widely used in anesthesia. They may promote the development of airway allergy, however, the background mechanisms are still unclear and need to be further investigated. Until now, a few cases of occupational asthma induced by QACs have been described and their involvement in contact dermatitis has been documented. The possibility of anaphylaxis due to QACs cannot be excluded as well. Med Pr 2014;65(5:675–682
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International Nuclear Information System (INIS)
Shrishma Paik; Biswas, S.; Bhattacharya, S.; Roy, S.B.
2013-01-01
Stripping studies of U(VI) from loaded solvent TBP/n-paraffin was carried out using ammonium nitrate solution as strippant. Effects of various stripping parameters such as concentration of ammonium nitrate solution, U(VI) concentration in organic phase, initial pH of strippant, temperature etc. have been investigated in detail. Kinetics of the stripping process by ammonium nitrate was found to be slower than that of stripping with water. It was observed that with the increase in ammonium nitrate concentration in aqueous solution, stripping of U(VI) decreased. With the increase in U(VI) loading in the organic phase, there was an increase in uranium stripping for ammonium nitrate whereas for distilled water it becomes reverse. With the increase in pH of the aqueous ammonium nitrate solution, stripping increased up to a certain pH of 8.5 and after that precipitation of uranium started. Increase in temperature of the biphasic system shows an enhancing effect of U(VI) stripping. Evaluation of thermodynamic data such as ΔH indicated that the process is endothermic. Based on the optimized conditions, McCabe-Thiele diagram was constructed for U(VI) stripping using ammonium nitrate solution at room temperature. (author)
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Zhao, Xue Qiang; Guo, Shi Wei; Shinmachi, Fumie; Sunairi, Michio; Noguchi, Akira; Hasegawa, Isao; Shen, Ren Fang
2013-01-01
Acidic soils are dominated chemically by more ammonium and more available, so more potentially toxic, aluminium compared with neutral to calcareous soils, which are characterized by more nitrate and less available, so less toxic, aluminium. However, it is not known whether aluminium tolerance and nitrogen source preference are linked in plants. This question was investigated by comparing the responses of 30 rice (Oryza sativa) varieties (15 subsp. japonica cultivars and 15 subsp. indica cultivars) to aluminium, various ammonium/nitrate ratios and their combinations under acidic solution conditions. indica rice plants were generally found to be aluminium-sensitive and nitrate-preferring, while japonica cultivars were aluminium-tolerant and relatively ammonium-preferring. Aluminium tolerance of different rice varieties was significantly negatively correlated with their nitrate preference. Furthermore, aluminium enhanced ammonium-fed rice growth but inhibited nitrate-fed rice growth. The results suggest that aluminium tolerance in rice is antagonistic with nitrate preference and synergistic with ammonium preference under acidic solution conditions. A schematic diagram summarizing the interactions of aluminium and nitrogen in soil-plant ecosystems is presented and provides a new basis for the integrated management of acidic soils.
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Synthesis of nano-crystalline hydroxyapatite and ammonium sulfate from phosphogypsum waste
Energy Technology Data Exchange (ETDEWEB)
Mousa, Sahar, E-mail: dollyriri@yahoo.com [Inorganic Chemistry Department, National Research Centre, Dokki, P.O.Box:12622, Postal code: 11787 Cairo (Egypt); King Abdulaziz University, Science and Art College, Chemistry Department, Rabigh Campus, P.O. Box:344, Postal code: 21911 Rabigh (Saudi Arabia); Hanna, Adly [Inorganic Chemistry Department, National Research Centre, Dokki, P.O.Box:12622, Postal code: 11787 Cairo (Egypt)
2013-02-15
Graphical abstract: TEM micrograph of dried HAP at 800 °C. -- Abstract: Phosphogypsum (PG) waste which is derived from phosphoric acid manufacture by using wet method was converted into hydroxyapatite (HAP) and ammonium sulfate. Very simple method was applied by reacting PG with phosphoric acid in alkaline medium with adjusting pH using ammonia solution. The obtained nano-HAP was dried at 80 °C and calcined at 600 °C and 900 °C for 2 h. Both of HAP and ammonium sulfate were characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR) to study the structural evolution. The thermal behavior of nano-HAP was studied; the particle size and morphology were estimated by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). All the results showed that HAP nano-crystalline and ammonium sulfate can successfully be produced from phosphogypsum waste.
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Synthesis of nano-crystalline hydroxyapatite and ammonium sulfate from phosphogypsum waste
International Nuclear Information System (INIS)
Mousa, Sahar; Hanna, Adly
2013-01-01
Graphical abstract: TEM micrograph of dried HAP at 800 °C. -- Abstract: Phosphogypsum (PG) waste which is derived from phosphoric acid manufacture by using wet method was converted into hydroxyapatite (HAP) and ammonium sulfate. Very simple method was applied by reacting PG with phosphoric acid in alkaline medium with adjusting pH using ammonia solution. The obtained nano-HAP was dried at 80 °C and calcined at 600 °C and 900 °C for 2 h. Both of HAP and ammonium sulfate were characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR) to study the structural evolution. The thermal behavior of nano-HAP was studied; the particle size and morphology were estimated by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). All the results showed that HAP nano-crystalline and ammonium sulfate can successfully be produced from phosphogypsum waste.
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Energy Technology Data Exchange (ETDEWEB)
Wei Zaishan [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)], E-mail: weizaishan98@163.com; Lin Zhehang; Niu Hejingying; He Haiming; Ji Yongfeng [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)
2009-03-15
Microwave reactor with ammonium bicarbonate (NH{sub 4}HCO{sub 3}) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) from flue gas. The results showed that the microwave reactor filled with NH{sub 4}HCO{sub 3} and zeolite could reduce SO{sub 2} to sulfur with the best desulfurization efficiency of 99.1% and reduce NO{sub x} to nitrogen with the best NO{sub x} purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO{sub x} concentration has little effect on denitrification but has no influence on desulfurization, SO{sub 2} concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO{sub 2}, NO{sub x} and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent.
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Teh, Amy Huei Teen; Lee, Sui Mae; Dykes, Gary A
2016-12-01
Campylobacter jejuni is one of the most common causes of bacterial gastrointestinal food-borne infection worldwide. It has been suggested that biofilm formation may play a role in survival of these bacteria in the environment. In this study, the influence of prior modes of growth (planktonic or sessile), temperatures (37 and 42 °C), and nutrient conditions (nutrient broth and Mueller-Hinton broth) on biofilm formation by eight C. jejuni strains with different antibiotic resistance profiles was examined. The ability of these strains to form biofilm on different abiotic surfaces (stainless steel, glass, and polystyrene) as well as factors potentially associated with biofilm formation (bacterial surface hydrophobicity, auto-aggregation, and initial attachment) was also determined. The results showed that cells grown as sessile culture generally have a greater ability to form biofilm (P Biofilm was also greater (P biofilm formation in a strain-dependent manner. The strains were able to attach and form biofilms on different abiotic surfaces, but none of them demonstrated strong, complex, or structured biofilm formation. There were no clear trends between the bacterial surface hydrophobicity, auto-aggregation, attachment, and biofilm formation by the strains. This finding suggests that environmental factors did affect biofilm formation by C. jejuni, and they are more likely to persist in the environment in the form of mixed-species rather than monospecies biofilms.
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Proton- and ammonium- sensing by histaminergic neurons controlling wakefulness.
Directory of Open Access Journals (Sweden)
Yvgenij eYanovsky
2012-04-01
Full Text Available Orexinergic and histaminergic neurons in the posterior hypothalamus are involved in the control of arousal. Extracellular levels of acid /CO2 are fundamental physicochemical signals controlling wakefulness and breathing. Acidification excites orexinergic neurons like the chemosensory neurons in the brain stem. Hypercapnia induces c-Fos expression, a marker for increased neuronal activity, in the rat histaminergic tuberomamillary nucleus (TMN, but the mechanisms of this excitation are unknown. Acid-sensing ion channels (ASICs are gated by protons and also by ammonium. Recordings in rat brain slices revealed now that acidification within the physiological range (pH from 7.3 to 7.0 as well as ammonium chloride (5mM excite histaminergic neurons. We detected variable combinations of 4 known types of ASICs in single TMN neurons, along with the pharmacological properties of pH-induced current. At pH 7.0 however, activation of ASICs in TMN neurons was negligible. Block of type I metabotropic glutamate receptors abolished proton- but not ammonium- induced excitation. Mouse TMN neurons were identified within a novel HDC-Cre transgenic reporter mouse line. In contrast to the rat these lacked pH 7.0-induced excitation and showed only a minimal response to the mGluR I agonist DHPG (0.5µM. Ammonium-induced excitation was similar in mouse and rat. Thus glutamate, which is released by glial cells and orexinergic axons amplifies CO2/acid-induced arousal through the recruitment of the histaminergic system in rat but not in mouse. These results are relevant for the understanding of neuronal mechanisms controlling H+/CO2-induced arousal in hepatic encephalopathy and obstructive sleep apnoea. The new HDC-Cre mouse model will be a useful tool for studying the physiological and pathophysiological roles of the histaminergic system.
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Optimization of nutritional requirements and ammonium feeding ...
African Journals Online (AJOL)
Statistical experiment design and data analysis were used to establish the major factors in a chemically defined medium and to develop an ammonium control strategy to optimize the specific vitamin B12 production rate (Yp) of Pseudomonas denitrificans. Through Plackett-Burman design, the major factors of glucose, ...
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Phytoplankton and some abiotic features of El-Bardawil Lake, Sinai ...
African Journals Online (AJOL)
Phytoplankton and some abiotic features of El-Bardawil Lake, Sinai, Egypt. H Touliabah, HM Safik, MM Gab-Allah, WD Taylor. Abstract. El-Bardawil Lake is a large coastal lagoon on the Mediterranean coast of Sinai, Egypt. Although it is shallow and oligotrophic, it is one of the most important lakes in Egypt as a source of ...
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Influence of abiotic stresses on the winter wheat sprouting plants
Czech Academy of Sciences Publication Activity Database
Bláha, L.; Hnilička, F.; Kadlec, P.; Smrčková-Jankovská, P.; Macháčková, Ivana; Sychrová, E.; Kohout, Ladislav
2008-01-01
Roč. 3, č. 3 (2008), s. 389-390 ISSN 1125-4718. [Congress of the European Society for Agronomy /10./. 15.09.2008-19.09.2008, Bologna] R&D Projects: GA MZe QF3056 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z40550506 Keywords : brassinosteroids * abiotic stress * emergency Subject RIV: CC - Organic Chemistry
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Abiotic and biotic drivers of biomass change in a Neotropical forest
Sande, van der M.T.; Pena Claros, M.; Ascarrunz, Nataly; Arets, E.J.M.M.; Licona, J.C.; Toledo, Marisol; Poorter, L.
2017-01-01
Summary
1. Tropical fores ts play an important role in the global carbon cycle, but the drivers of net forest biomass change (i.e. net carbon sequestration) are poorly understood. Here, we evaluate how abiotic factors (soil co nditions and disturbance) and biotic factors (forest structure, -
Poaceae vs. Abiotic Stress: Focus on Drought and Salt Stress, Recent Insights and Perspectives
Directory of Open Access Journals (Sweden)
Simone Landi
2017-07-01
Full Text Available Poaceae represent the most important group of crops susceptible to abiotic stress. This large family of monocotyledonous plants, commonly known as grasses, counts several important cultivated species, namely wheat (Triticum aestivum, rice (Oryza sativa, maize (Zea mays, and barley (Hordeum vulgare. These crops, notably, show different behaviors under abiotic stress conditions: wheat and rice are considered sensitive, showing serious yield reduction upon water scarcity and soil salinity, while barley presents a natural drought and salt tolerance. During the green revolution (1940–1960, cereal breeding was very successful in developing high-yield crops varieties; however, these cultivars were maximized for highest yield under optimal conditions, and did not present suitable traits for tolerance under unfavorable conditions. The improvement of crop abiotic stress tolerance requires a deep knowledge of the phenomena underlying tolerance, to devise novel approaches and decipher the key components of agricultural production systems. Approaches to improve food production combining both enhanced water use efficiency (WUE and acceptable yields are critical to create a sustainable agriculture in the future. This paper analyzes the latest results on abiotic stress tolerance in Poaceae. In particular, the focus will be directed toward various aspects of water deprivation and salinity response efficiency in Poaceae. Aspects related to cell wall metabolism will be covered, given the importance of the plant cell wall in sensing environmental constraints and in mediating a response; the role of silicon (Si, an important element for monocots' normal growth and development, will also be discussed, since it activates a broad-spectrum response to different exogenous stresses. Perspectives valorizing studies on landraces conclude the survey, as they help identify key traits for breeding purposes.
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Rapeseed with tolerance to the non selective herbicide glufosinate ammonium
Energy Technology Data Exchange (ETDEWEB)
Rasche, E. [Hoechst Schering AgrEvo GmbH, Frankfurt am Main (Germany)
1998-12-31
Weed control with herbicides is essential to grow rapeseed. Glufosinate Ammonium is used as a non selective herbicide successfully in many countries for over 10 years. It conforms well with ever increasing safety standards for human beings, animals and the environment. The tolerance of rapeseed and other crop plants was achieved by genetic modification. A resistance gene (PAT or BAR) was transfered into previously susceptible rapeseed plants. This new approach allowed the development of Glufosinate Ammonium as an almost ideal selective herbicide. In cooperation with major seed companies and by own breeding programmes new Glufosinate tolerant rapeseed varieties and hybrids are developed. Data on metabolism, toxicity, residues, efficacy etc. were generated to get registration for the selective herbicide use. In addition various studies were done for safety assessments of the PAT gene and the modified rapeseed. In spring 1995 Canadian authorities granted worldwide the first approvals for the selective use of Glufosinate Ammonium (trademark Liberty) and Glufosinate tolerant (trademark and logo Liberty Link) spring rapeseed (Canola). After a successful launch in 1995 about 150.000 ha of Liberty Link Canola were grown and treated with Liberty in 1996. The Liberty Link Canola growers were very well satisfied. In a grower survey 84% stated that they will definitely use the Liberty Link System again. In Europe registrations for Glufosinate Ammonium as a selective herbicide and for the first Glufosinate tolerant rapeseed varieties are expected in the course of 1997. The Liberty Link System will be launched in rapeseed most probably in 1998. (orig.)
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Nitrogen doping in atomic layer deposition grown titanium dioxide films by using ammonium hydroxide
Energy Technology Data Exchange (ETDEWEB)
Kaeaeriaeinen, M.-L., E-mail: marja-leena.kaariainen@lut.fi; Cameron, D.C.
2012-12-30
Titanium dioxide films have been created by atomic layer deposition using titanium chloride as the metal source and a solution of ammonium hydroxide in water as oxidant. Ammonium hydroxide has been used as a source of nitrogen for doping and three thickness series have been deposited at 350 Degree-Sign C. A 15 nm anatase dominated film was found to possess the highest photocatalytic activity in all film series. Furthermore almost three times better photocatalytic activity was discovered in the doped series compared to undoped films. The doped films also had lower resistivity. The results from X-ray photoemission spectroscopy showed evidence for interstitial nitrogen in the titanium dioxide structure. Besides, there was a minor red shift observable in the thickest samples. In addition the film conductivity was discovered to increase with the feeding pressure of ammonium hydroxide in the oxidant precursor. This may indicate that nitrogen doping has caused the decrease in the resistivity and therefore has an impact as an enhanced photocatalytic activity. The hot probe test showed that all the anatase or anatase dominant films were p-type and all the rutile dominant films were n-type. The best photocatalytic activity was shown by anatase-dominant films containing a small amount of rutile. It may be that p-n-junctions are formed between p-type anatase and n-type rutile which cause carrier separation and slow down the recombination rate. The combination of nitrogen doping and p-n junction formation results in superior photocatalytic performance. - Highlights: Black-Right-Pointing-Pointer We found all N-doped and undoped anatase dominating films p-type. Black-Right-Pointing-Pointer We found all N-doped and undoped rutile dominating films n-type. Black-Right-Pointing-Pointer We propose that p-n junctions are formed in anatase-rutile mixture films. Black-Right-Pointing-Pointer We found that low level N-doping has increased TiO{sub 2} conductivity. Black
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Briquetting of Tuncbilek lignite fines by using ammonium nitrohumate as a binder
Energy Technology Data Exchange (ETDEWEB)
Yildirim, M.; Ozbayoglu, G. [Cukurova University, Adana (Turkey). Mining Engineering Dept.
2004-03-01
Results of experiments on the briquetting of Tuncbilek lignite fines using ammonium nitrohumate (anh), a low calorific value, young lignite-derived humic acid salt solution, are reported. The particulate material was blended with ammonium nitrohumate serving as the binder. In the briquetting tests, the effects of moisture content, pressure, binder content, nitrogen content and heat treatment were investigated. Durable briquettes, in terms of mechanical strength and water resistance, were produced with a 7% binder content at 10.5% moisture, following pressing at 1280 kg/cm{sup 2} and drying at 165{sup o}C for 1 h. The briqueues produced with ammonium nitrohumate had better combustion properties than run-of-mine samples; the contribution of the binder to smoke and sulphur emissions was very low and fine dust particles were negligible.
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VARIATION IN THE SENSITIVITY OF WANDERING JEW PLANTS TO GLUFOSINATE AMMONIUM
BRITO, IVANA PAULA FERRAZ SANTOS DE; MARCHESI, BRUNA BARBOZA; SILVA, ILCA PUERTAS FREITAS E; CARBONARI, CAIO ANTONIO; VELINI, EDIVALDO DOMINGUES
2017-01-01
ABSTRACT This study aimed to identify the response of wandering jew (Commelina benghalensis L.) plants to different doses of glufosinate ammonium and the sensitivity of plants populations to the herbicide. Two studies were conducted, both in a greenhouse, and were repeated at different times. In the first study, two experiments were conducted to examine the dose-response curve using seven different doses of the glufosinate ammonium herbicide (0, 50, 100, 200, 400, 800, and 1600 g a.i. ha-1) w...
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VARIATION IN THE SENSITIVITY OF WANDERING JEW PLANTS TO GLUFOSINATE AMMONIUM
IVANA PAULA FERRAZ SANTOS DE BRITO; BRUNA BARBOZA MARCHESI; ILCA PUERTAS FREITAS E SILVA; CAIO ANTONIO CARBONARI; EDIVALDO DOMINGUES VELINI
2017-01-01
This study aimed to identify the response of wandering jew (Commelina benghalensis L.) plants to different doses of glufosinate ammonium and the sensitivity of plants populations to the herbicide. Two studies were conducted, both in a greenhouse, and were repeated at different times. In the first study, two experiments were conducted to examine the dose-response curve using seven different doses of the glufosinate ammonium herbicide (0, 50, 100, 200, 400, 800, and 1600 g a.i. ha-1) with four ...
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Effect of N-protecting compound ammonium bicarbonate and its mechanism
International Nuclear Information System (INIS)
Guo Zhifen; Zeng Hanting; Huang Min; Tu Shuxin; Wen Xianfang
2004-01-01
A kind of N-protecting compound ammonium bicarbonate fertilizer was created. Compared with common ammonium bicarbonate, the fertilizer can raise nitrogen use efficiency by 5.2%-15% and reduce ammonia loss due to volatilization by 5%-12%. Yields of rice and cotton were raised by 5%-10% and 6%-20%, respectively. And it also has the following characteristics, such as hard lump not be formed, easy to use, less bad smell caused by ammonia, reducing of production cost, etc. Demonstration of applying this fertilizer to cotton and rice in more than 13.3 hm 2 showed good effect on increasing crop yield
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Ammonium dinitramide (ADN)-Prilling, coating, and characterization
Energy Technology Data Exchange (ETDEWEB)
Heintz, Thomas; Pontius, Heike; Aniol, Jasmin; Birke, Christoph; Leisinger, Karlfred; Reinhard, Werner [Fraunhofer-Institut Chemische Technologie ICT, Pfinztal (Germany)
2009-06-15
Ammonium dinitramide (ADN) is the promising oxidizer, which is expected to be applied, e.g., in solid rocket propellants. The manufacturing of spherical ADN particles (the so-called ADN-Prills) with useful morphology and reproducible quality is realized by means of the emulsion crystallization process. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
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Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth.
Xie, Xueshu; Backman, Daniel; Lebedev, Albert T; Artaev, Viatcheslav B; Jiang, Liying; Ilag, Leopold L; Zubarev, Roman A
2015-09-28
Sixty years after the seminal Miller-Urey experiment that abiotically produced a mixture of racemized amino acids, we provide a definite proof that this primordial soup, when properly cooked, was edible for primitive organisms. Direct admixture of even small amounts of Miller-Urey mixture strongly inhibits E. coli bacteria growth due to the toxicity of abundant components, such as cyanides. However, these toxic compounds are both volatile and extremely reactive, while bacteria are highly capable of adaptation. Consequently, after bacterial adaptation to a mixture of the two most abundant abiotic amino acids, glycine and racemized alanine, dried and reconstituted MU soup was found to support bacterial growth and even accelerate it compared to a simple mixture of the two amino acids. Therefore, primordial Miller-Urey soup was perfectly suitable as a growth media for early life forms.
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He, Tieshi; Meng, Xiangling; Nie, Junping; Tong, Yujin; Cai, Kedi
2016-06-08
Thermally reduced graphene oxide (RGO) electrochemically activated by a quaternary alkyl ammonium-based organic electrolytes/activated carbon (AC) electrode asymmetric capacitor is proposed. The electrochemical activation process includes adsorption of anions into the pores of AC in the positive electrode and the interlayer intercalation of cations into RGO in the negative electrode under high potential (4.0 V). The EA process of RGO by quaternary alkyl ammonium was investigated by X-ray diffraction and electrochemical measurements, and the effects of cation size and structure were extensively evaluated. Intercalation by quaternary alkyl ammonium demonstrates a small degree of expansion of the whole crystal lattice (d002) and a large degree of expansion of the partial crystal lattice (d002) of RGO. RGO electrochemically activated by bis-spiro quaternary alkyl ammonium in propylene carbonate/AC asymmetric capacitor exhibits good activated efficiency, high specific capacity, and stable cyclability.
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Directory of Open Access Journals (Sweden)
Dinorah Torres-Idavoy
2015-08-01
Full Text Available The ammonium salts are used in fermentations to supplement the deficient amounts of nitrogen and stabilize the pH of the culture medium. The excess ammonium ion exerts a detrimental effect on the fermentation process inhibiting microbial growth. An analytical method based on Neesler reagent was developed for monitoring and controlling the concentration of ammonium during the fermentation process. The test was standardized, by means of the selection of measuring equipment, and the reaction time as well as comparing standards of ammonium salts. The method was characterized with the evaluation of the next parameters: Specificity, Linearity and Range, Quantification Limit, Accuracy and Precision. The method proved to be specific. Two linear curves were defined in the ranges of concentrations of ammonium chloride salt (2-20 μg/ml and ammonium sulfate salt (5-30 μg/ml. The limits of quantification were the lowest points of each one. The method proved to be accurate and precise. This assay was applied to samples of the yeast culture and bacteria of the genus Saccharomyces and E. coli respectively. A novel method in micro plate for quantification and analytical control of ammonia was developed. This method is used to control this fundamental chemical component in the fermentations, to optimize the culture medium. Thus, an appropriate expression of recombinant proteins and proper vaccine candidates for clinical use are achieved
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Biofilm formation on abiotic surfaces in fresh produce processing facilities might play a role in foodborne outbreaks by providing protective microniches for pathogenic bacteria. Our previous study showed that a strain of Ralstonia insidiosa isolated from a fresh produce processing plant could enhan...
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Dark CO2 fixation in leaves of tomato plants grown with ammonium and nitrate at nitrogen sources
International Nuclear Information System (INIS)
Ikeda, M.; Yamada, Y.
1981-01-01
The dark (non-photosynthetic) CO 2 fixation was studied in the leaves of ammonium-fed and nitrate-fed tomato plants. The ability to fix 14 CO 2 in the dark of ammonium-fed plants was remarkably lower as compared with nitrate-fed plants, supporting the previous finding that the synthesis of C 4 -compounds from C 3 -compounds was reduced in the leaves of ammonium-fed plants. There was no difference in the activity of PEP carboxylase in extracts prepared from the leaves between both the plants during an early period of the treatment. However, the enzyme activity began to decrease rapidly in ammonium-fed plants 4 days after the treatment. By long-term treatments, the enzyme activity in ammonium-fed plants became half as high as that of nitrate-fed plants. The decreased PEP carboxylase activity in ammonium-fed plants was not associated with the presence of NH 4 -N and the absence of NO 3 -N in the leaf extract, and was not restored by the addition of the leaf extract from nitrate-fed plants. It is concluded that the decreased rate of synthesis of C 4 -compounds from C 3 -compounds in ammonium-fed plants is closely associated with a decrease in the dark fixation involving PEP carboxylase. (orig.)
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Laitinen, Pirkko; Siimes, Katri; Rämö, Sari; Jauhiainen, Lauri; Eronen, Liisa; Oinonen, Seija; Hartikainen, Helinä
2008-01-01
The increased use of herbicides poses a risk to the aquatic environment. Easy and economical methods are needed to identify the fields where specific environment protection measures are needed. Phosphorus (P) and organophosphorus herbicides compete for the same adsorption sites in soil. In this study the relationship between P obtained in routine Finnish agronomic tests (acid ammonium acetate [P(AC)]) and adsorption of glyphosate and glufosinate-ammonium was investigated to determine whether P(AC) values could be used in the risk assessment. The adsorption of glyphosate ((N-(phosphonomethyl)glycine) and glufosinate-ammonium (2-amino-4-(hydroxymethylphosphinyl)butanoic acid) was studied in a clay and a sandy loam soil enriched with increasing amounts of P added as potassium dihydrogen phosphate. Desorption was also determined for some P-enriched soil samples. The adsorption of both herbicides diminished with increasing P(AC) value. The correlations between Freundlich adsorption coefficients obtained in the adsorption tests and P(AC) were nonlinear but significant (r > 0.98) in both soils. The exponential models of the relationship between soil P(AC) values and glyphosate adsorption were found to fit well to an independent Finnish soil data set (P glufosinate-ammonium). The desorption results showed that glufosinate-ammonium sorption is not inversely related to soil P status, and the high correlation coefficients obtained in the test of the model were thus artifacts caused by an abnormal concentration of exchangeable potassium in soil. The solved equations are a useful tool in assessing the leaching risks of glyphosate, but their use for glufosinate-ammonium is questionable.
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Biofilm Formation and Immunomodulatory Activity of Proteus mirabilis Clinically Isolated Strains
Directory of Open Access Journals (Sweden)
Alessandra Fusco
2017-02-01
Full Text Available Urinary tract infections (UTIs and catheter-associated UTIs (CAUTIs are the principal hospital-acquired infections. Proteus mirabilis is characterized by several virulence factors able to promote adhesion and biofilm formation and ameliorate the colonization of urinary tract and the formation of crystalline biofilms on the abiotic surface of the urinary catheters. Since, to date, the role of P. mirabilis in the etiopathogenesis of different types of urinary tract infections is not well established, in this study we sought to characterize two different clinically isolated strains of P. mirabilis (PM1 and PM2 with distinctive phenotypes and analyzed various virulence factors possibly implicated in the ability to induce UTIs and CAUTIs. In particular, we analyzed motility, biofilm formation both on abiotic and biotic surfaces of PM1 and PM2 and paralleled these parameters with the ability to induce an inflammatory response in an epithelial cell model. Results showed that PM1 displayed major motility and a capacity to form biofilm and was associated with an anti-inflammatory response of host cells. Conversely, PM2 exhibited lack motility and a had slower organization in biofilm but promoted an increase of proinflammatory cytokine expression in infected epithelial cells. Our study provides data useful to start uncovering the pathologic basis of P. mirabilis-associated urinary infections. The evidence of different virulence factors expressed by PM1 and PM2 highlights the possibility to use precise and personalized therapies targeting specific virulence pathways.
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Biofilm Formation and Immunomodulatory Activity of Proteus mirabilis Clinically Isolated Strains.
Fusco, Alessandra; Coretti, Lorena; Savio, Vittoria; Buommino, Elisabetta; Lembo, Francesca; Donnarumma, Giovanna
2017-02-15
Urinary tract infections (UTIs) and catheter-associated UTIs (CAUTIs) are the principal hospital-acquired infections. Proteus mirabilis is characterized by several virulence factors able to promote adhesion and biofilm formation and ameliorate the colonization of urinary tract and the formation of crystalline biofilms on the abiotic surface of the urinary catheters. Since, to date, the role of P. mirabilis in the etiopathogenesis of different types of urinary tract infections is not well established, in this study we sought to characterize two different clinically isolated strains of P. mirabilis (PM1 and PM2) with distinctive phenotypes and analyzed various virulence factors possibly implicated in the ability to induce UTIs and CAUTIs. In particular, we analyzed motility, biofilm formation both on abiotic and biotic surfaces of PM1 and PM2 and paralleled these parameters with the ability to induce an inflammatory response in an epithelial cell model. Results showed that PM1 displayed major motility and a capacity to form biofilm and was associated with an anti-inflammatory response of host cells. Conversely, PM2 exhibited lack motility and a had slower organization in biofilm but promoted an increase of proinflammatory cytokine expression in infected epithelial cells. Our study provides data useful to start uncovering the pathologic basis of P. mirabilis -associated urinary infections. The evidence of different virulence factors expressed by PM1 and PM2 highlights the possibility to use precise and personalized therapies targeting specific virulence pathways.
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Biofilm formation on abiotic surfaces
DEFF Research Database (Denmark)
Tang, Lone
2011-01-01
Bacteria can attach to any surface in contact with water and proliferate into complex communities enclosed in an adhesive matrix, these communities are called biofilms. The matrix makes the biofilm difficult to remove by physical means, and bacteria in biofilm can survive treatment with many...
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The evolution of hydrogen and iodine by the decomposition of ammonium iodide and hydrogen iodide
International Nuclear Information System (INIS)
Ishikawa, Hiroshi; Nakane, Masanori; Ishii, Eiichi; Uehara, Itsuki; Miyake, Yoshizo
1977-01-01
As a fundamental study on thermochemical production of hydrogen from water, the evolution of hydrogen and iodine from ammonium iodide and hydrogen iodide was investigated. Hydrogen was evolved by the reaction of nickel with ammonium iodide or with hydrogen iodide, and the resulting nickel(II) iodide was decomposed thermally at 600 -- 700 0 C to form nickel. First, the iodination of powdered nickel with ammonium iodide was studied by heating their powder mixture. The maximum yield of hydrogen was obtained at a temperature near 430 0 C. The iodination of powdered nickel with gaseous ammonium iodide or with dry hydrogen iodide gas was also investigated. In this case, coating of nickel particles with a layer of resulting nickel(II) iodide prevented further conversion of nickel and lowered the reaction rate. Such a retardation effect was appreciably lessened by use of carrier. When nickel was supported on such a carrier as ''isolite'', the nickel was converted into nickel(II) iodide easily. In a reaction temperature from 400 to 500 0 C, the rate of reaction between nickel and hydrogen iodide increased slightly with the elevation of the reaction temperature. In the case of ammonium iodide, the reaction rate was higher than that for hydrogen iodide and decreased apparently with the elevation of the reaction temperature, because ammonium iodide decomposed to ammonia and hydrogen iodide. Tests using a fixed bed reactor charged with 8 -- 10 mesh ''isolite''-nickel (30 wt%) were also carried out. The maximum yield of hydrogen was about 80% for ammonium iodide at 430 0 C of reaction temperature and 60% for hydrogen iodide at 500 0 C. (auth.)
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Byram, Chandu; Moram, Sree Sathya Bharathi; Soma, Venugopal Rao
2018-04-01
In this paper, we present the results from fabrication studies of Ag, Au, and Ag-Au alloy nanoparticles (NPs) using picosecond laser ablation technique in the presence of liquid media. The alloy formation in the NPs was confirmed from UV-Visible measurements. The shape and crystallinity of NPs were investigated by using high resolution transmission electron microscopy (HRTEM), selected area diffraction pattern (SAED) and energy dispersive spectroscopy (EDS). The SERS effect of fabricated NPs was tested with methylene blue and an explosive molecule (ammonium perchlorate) using a portable Raman spectrometer and achieved EFs of ˜106.
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Derivatization of peptides as quaternary ammonium salts for sensitive detection by ESI-MS.
Cydzik, Marzena; Rudowska, Magdalena; Stefanowicz, Piotr; Szewczuk, Zbigniew
2011-06-01
A series of model peptides in the form of quaternary ammonium salts at the N-terminus was efficiently prepared by the solid-phase synthesis. Tandem mass spectrometric analysis of the peptide quaternary ammonium derivatives was shown to provide sequence confirmation and enhanced detection. We designed the 2-(1,4-diazabicyclo[2.2.2] octylammonium)acetyl quaternary ammonium group which does not suffer from neutral losses during MS/MS experiments. The presented quaternization of 1,4-diazabicyclo[2.2.2]octane (DABCO) by iodoacetylated peptides is relatively easy and compatible with standard solid-phase peptide synthesis. This methodology offers a novel sensitive approach to analyze peptides and other compounds. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
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International Nuclear Information System (INIS)
Józefczak, A.; Leszczyński, B.; Skumiel, A.; Hornowski, T.
2016-01-01
Magnetic nanoparticles show unique properties and find many applications because of the possibility to control their properties using magnetic field. Magnetic nanoparticles are usually synthesized chemically and modification of the particle surface is necessary. Another source of magnetic nanoparticles are various magnetotactic bacteria. These biogenic nanoparticles (magnetosomes) represent an attractive alternative to chemically synthesized iron oxide particles because of their unique characteristics and a high potential for biotechnological and biomedical applications. This work presents a comparison between acoustic properties of biogenic and abiotic magnetite nanoparticle suspensions. Experimental studies have shown the influence of a biological membrane on the ultrasound properties of magnetosomes suspension. Finally the heat effect in synthetic and biogenic magnetite nanoparticles is also discussed. The experimental study shows that magnetosomes present good heating efficiency. - Highlights: • A biogenic and abiotic magnetite nanoparticle suspensions are investigated. • A comparison between ultrasonic properties and heat effects is presented. • Magnetosomes and abiotic magnetite nanoparticles exhibit good heating efficiency.
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Zhai, Yiqian; Zhang, Lichao; Xia, Chuan; Fu, Silu; Zhao, Guangyao; Jia, Jizeng; Kong, Xiuying
2016-05-13
Although bHLH transcription factors play important roles regulating plant development and abiotic stress response and tolerance, few functional studies have been performed in wheat. In this study, we isolated and characterized a bHLH gene, TabHLH39, from wheat. The TabHLH39 gene is located on wheat chromosome 5DL, and the protein localized to the nucleus and activated transcription. TabHLH39 showed variable expression in roots, stems, leaves, glumes, pistils and stamens and was induced by polyethylene glycol, salt and cold treatments. Further analysis revealed that TabHLH39 overexpression in Arabidopsis significantly enhanced tolerance to drought, salt and freezing stress during the seedling stage, which was also demonstrated by enhanced abiotic stress-response gene expression and changes to several physiological indices. Therefore, TabHLH39 has potential in transgenic breeding applications to improve abiotic stress tolerance in crops. Copyright © 2016 Elsevier Inc. All rights reserved.
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Hazarika, Pranjal; Rajam, Manchikatla Venkat
2011-04-01
Recent findings have implicated the role of polyamines (putrescine, spermidine and spermine) in stress tolerance. Therefore, the present work was carried out with the goal of generating transgenic tomato plants with human S-adenosylmethionine decarboxylase (samdc) gene, a key gene involved in biosynthesis of polyamines, viz. spermidine and spermine and evaluating the transgenic plants for tolerance to both biotic and abiotic stresses. Several putative transgenic tomato plants with normal phenotype were obtained, and the transgene integration and expression was validated by PCR, Southern blot analysis and RT-PCR analysis, respectively. The transgenic plants exhibited high levels of polyamines as compared to the untransformed control plants. They also showed increased resistance against two important fungal pathogens of tomato, the wilt causing Fusarium oxysporum and the early blight causing Alternaria solani and tolerance to multiple abiotic stresses such as salinity, drought, cold and high temperature. These results suggest that engineering polyamine accumulation can confer tolerance to both biotic and abiotic stresses in plants.
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Nitrogen loss in Brachiaria decumbens after application of glyphosate or glufosinate-ammonium
Damin,Virginia; Franco,Henrique Coutinho Junqueira; Moraes,Milton Ferreira; Franco,Ademir; Trivelin,Paulo Cesar Ocheuze
2008-01-01
Nitrogen losses from the soil-plant system may be influenced by herbicide applications. In order to evaluate N loss in brachiaria (Brachiaria decumbens) after application of the herbicides glyphosate and glufosinate-ammonium, an experiment was carried out in a greenhouse as a completely randomized design, with three treatments and six replicates. Treatments were as follows: i) desiccation of brachiaria-plants with glyphosate; ii) desiccation of brachiaria-plants with glufosinate-ammonium; and...
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Ammonium diphosphitoindate(III
Directory of Open Access Journals (Sweden)
Farida Hamchaoui
2013-04-01
Full Text Available The crystal structure of the title compound, NH4[In(HPO32], is built up from InIII cations (site symmetry 3m. adopting an octahedral environment and two different phosphite anions (each with site symmetry 3m. exhibiting a triangular–pyramidal geometry. Each InO6 octahedron shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO3 group shares all its O atoms with three different metal cations, leading to [In(HPO32]− layers which propagate in the ab plane. The ammonium cation likewise has site symmetry 3m.. In the structure, the cations are located between the [In(HPO32]− layers of the host framework. The sheets are held together by hydrogen bonds formed between the NH4+ cations and the O atoms of the framework.
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Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams
International Nuclear Information System (INIS)
Freeman, W.P.; Mohacsi, T.G.; Kovach, J.L.
1985-01-01
The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange