Comustion of HAN-Based Monopropellant Droplets in Reduced Gravity

NASA Technical Reports Server (NTRS)

Shaw, B. D.

2001-01-01

Hydroxylammonium nitrate (HAN) is a major constituent in a class of liquid monopropellants that have many attractive characteristics and which display phenomena that differ significantly from other liquid monopropellants. They are composed primarily of HAN, H2O and a fuel species, often triethanolammonium nitrate (TEAN). HAN-based propellants have attracted attention as liquid gun propellants, and are attractive for NASA spacecraft propulsion applications. A representative propellant is XM46. This mixture is 60.8% HAN, 19.2% TEAN and 20% H2O by weight. Other HAN-based propellant mixtures are also of interest. For example, methanol and glycine have been investigated as potential fuel species for HAN-based monopropellants for thruster applications. In the present research, experimental and theoretical studies are performed on combustion of HAN-based monopropellant droplets. The fuel species considered are TEAN, methanol and glycine. Droplets initially in the mm size range are studied at pressures up to 30 atm. These pressures are applicable to spacecraft thruster applications. The droplets are placed in environments with various amounts of Ar, N2, O2, NO2 and N2O. Reduced gravity is employed to enable observations of burning rates and flame structures to be made without the complicating effects of buoyant and forced convection. Normal gravity experiments are also performed in this research program. The experiment goals are to provide accurate fundamental data on deflagration rates, gasphase temperature profiles, transient gas-phase flame behaviors, the onset of bubbling in droplets at lower pressures, and the low-pressure deflagration limit. Theoretical studies are performed to provide rational models of deflagration mechanisms of HAN-based liquid propellants. Besides advancing fundamental knowledge, this research should aid in applications (e.g., spacecraft thrusters and liquid propellant guns) of this unique class of monopropellants.

SEPARATION OF URANIUM, PLUTONIUM AND FISSION PRODUCTS

DOEpatents

Nicholls, C.M.; Wells, I.; Spence, R.

1959-10-13

The separation of uranium and plutonium from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in nitric acid to provide an aqueous solution 3N in nitric acid. The fission products of the solution are extruded by treating the solution with dibutyl carbitol substantially 1.8N in nitric acid. The organic solvent phase is separated and neutralized with ammonium hydroxide and the plutonium reduced with hydroxylamine base to the trivalent state. Treatment of the mixture with saturated ammonium nitrate extracts the reduced plutonium and leaves the uranium in the organic solvent.

{sup 19}F NMR measurements of NO production in hypertensive ISIAH and OXYS rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobko, Andrey A.; Sergeeva, Svetlana V.; Bagryanskaya, Elena G.

2005-05-06

Recently we demonstrated the principal possibility of application of {sup 19}F NMR spin-trapping technique for in vivo {sup {center_dot}}NO detection [Free Radic. Biol. Med. 36 (2004) 248]. In the present study, we employed this method to elucidate the significance of {sup {center_dot}}NO availability in animal models of hypertension. In vivo {sup {center_dot}}NO-induced conversion of the hydroxylamine of the fluorinated nitronyl nitroxide (HNN) to the hydroxylamine of the iminonitroxide (HIN) in hypertensive ISIAH and OXYS rat strains and normotensive Wistar rat strain was measured. Significantly lower HIN/HNN ratios were measured in the blood of the hypertensive rats. The NMR data weremore » found to positively correlate with the levels of nitrite/nitrate evaluated by Griess method and negatively correlate with the blood pressure. In comparison with other traditionally used methods {sup 19}F NMR spectroscopy allows in vivo evaluation of {sup {center_dot}}NO production and provides the basis for in vivo {sup {center_dot}}NO imaging.« less

Utility of surface enhanced Raman spectroscopy (SERS) for elucidation and simultaneous determination of some penicillins and penicilloic acid using hydroxylamine silver nanoparticles.

PubMed

El-Zahry, Marwa R; Refaat, Ibrahim H; Mohamed, Horria A; Rosenberg, Erwin; Lendl, Bernhard

2015-11-01

Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r=0.9993) and in the case of penicilloic acid (r=0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanisms of N2O production in biological wastewater treatment under nitrifying and denitrifying conditions.

PubMed

Wunderlin, Pascal; Mohn, Joachim; Joss, Adriano; Emmenegger, Lukas; Siegrist, Hansruedi

2012-03-15

Nitrous oxide (N2O) is an important greenhouse gas and a major sink for stratospheric ozone. In biological wastewater treatment, microbial processes such as autotrophic nitrification and heterotrophic denitrification have been identified as major sources; however, the underlying pathways remain unclear. In this study, the mechanisms of N2O production were investigated in a laboratory batch-scale system with activated sludge for treating municipal wastewater. This relatively complex mixed population system is well representative for full-scale activated sludge treatment under nitrifying and denitrifying conditions. Under aerobic conditions, the addition of nitrite resulted in strongly nitrite-dependent N2O production, mainly by nitrifier denitrification of ammonia-oxidizing bacteria (AOB). Furthermore, N2O is produced via hydroxylamine oxidation, as has been shown by the addition of hydroxylamine. In both sets of experiments, N2O production was highest at the beginning of the experiment, then decreased continuously and ceased when the substrate (nitrite, hydroxylamine) had been completely consumed. In ammonia oxidation experiments, N2O peaked at the beginning of the experiment when the nitrite concentration was lowest. This indicates that N2O production via hydroxylamine oxidation is favored at high ammonia and low nitrite concentrations, and in combination with a high metabolic activity of ammonia-oxidizing bacteria (at 2 to 3 mgO2/l); the contribution of nitrifier denitrification by AOB increased at higher nitrite and lower ammonia concentrations towards the end of the experiment. Under anoxic conditions, nitrate reducing experiments confirmed that N2O emission is low under optimal growth conditions for heterotrophic denitrifiers (e.g. no oxygen input and no limitation of readily biodegradable organic carbon). However, N2O and nitric oxide (NO) production rates increased significantly in the presence of nitrite or low dissolved oxygen concentrations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hydroxylamine addition impact to Nitrosomonas europaea activity in the presence of monochloramine.

PubMed

Wahman, David G; Speitel, Gerald E

2015-01-01

In drinking water, monochloramine may promote ammonia–oxidizing bacteria (AOB) growth because of concurrent ammonia presence. AOB use (i) ammonia monooxygenase for biological ammonia oxidation to hydroxylamine and (ii) hydroxylamine oxidoreductase for biological hydroxylamine oxidation to nitrite. In addition, monochloramine and hydroxylamine abiotically react, providing AOB a potential benefit by removing the disinfectant (monochloramine) and releasing growth substrate (ammonia). Alternatively and because biological hydroxylamine oxidation supplies the electrons (reductant) required for biological ammonia oxidation, the monochloramine/hydroxylamine abiotic reaction represents a possible inactivation mechanism by consuming hydroxylamine and inhibiting reductant generation. To investigate the abiotic monochloramine and hydroxylamine reaction's impact on AOB activity, the current study used batch experiments with Nitrosomonas europaea (AOB pure culture), ammonia, monochloramine, and hydroxylamine addition. To decipher whether hydroxylamine addition benefitted N. europaea activity by (i) removing monochloramine and releasing free ammonia or (ii) providing an additional effect (possibly the aforementioned reductant source), a previously developed cometabolism model was coupled with an abiotic monochloramine and hydroxylamine model for data interpretation. N. europaea maintained ammonia oxidizing activity when hydroxylamine was added before complete ammonia oxidation cessation. The impact could not be accounted for by monochloramine removal and free ammonia release alone and was concentration dependent for both monochloramine and hydroxylamine. In addition, a preferential negative impact occurred for ammonia versus hydroxylamine oxidation. These results suggest an additional benefit of exogenous hydroxylamine addition beyond monochloramine removal and free ammonia release, possibly providing reductant generation.

Complete nitrification by Nitrospira bacteria

PubMed Central

Daims, Holger; Lebedeva, Elena V.; Pjevac, Petra; Han, Ping; Herbold, Craig; Albertsen, Mads; Jehmlich, Nico; Palatinszky, Marton; Vierheilig, Julia; Bulaev, Alexandr; Kirkegaard, Rasmus H.; von Bergen, Martin; Rattei, Thomas; Bendinger, Bernd; Nielsen, Per H.; Wagner, Michael

2016-01-01

Nitrification, the oxidation of ammonia via nitrite to nitrate, has always been considered as a two-step process catalyzed by chemolithoautotrophic microorganisms oxidizing either ammonia or nitrite. No known nitrifier carries out both steps, although complete nitrification should be energetically advantageous. This functional separation has puzzled microbiologists for a century. Here we report on the discovery and cultivation of a completely nitrifying bacterium from the genus Nitrospira, a globally distributed group of nitrite oxidizers. The genome of this chemolithoautotrophic organism encodes both the pathways for ammonia and nitrite oxidation, which are concomitantly expressed during growth by ammonia oxidation to nitrate. Genes affiliated with the phylogenetically distinct ammonia monooxygenase and hydroxylamine dehydrogenase genes of Nitrospira are present in many environments and were retrieved on Nitrospira-contigs in new metagenomes from engineered systems. These findings fundamentally change our picture of nitrification and point to completely nitrifying Nitrospira as key components of nitrogen-cycling microbial communities. PMID:26610024

Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms.

PubMed

Torres, M J; Simon, J; Rowley, G; Bedmar, E J; Richardson, D J; Gates, A J; Delgado, M J

2016-01-01

Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nitric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the application of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural efficiency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understanding of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation. © 2016 Elsevier Ltd. All rights reserved.

Process for Assessing the Stability of HAN (Hydroxylammonium Nitrate)-Based Liquid Propellants

DTIC Science & Technology

1989-02-09

Scholz, Guidelines by Messrs. Riedel - de Haen for Titration according to the Karl Fischer Method ), 3. Auflage/3rd Edition 1982 /22/ JANDER; G. and... Potentiometric determination of the equivalence point is the most suitable method /15/. Time is saved by using automatically recording titration 33...propellant. The water content of liquid propellants on the basis of HAN according to Fig. 6 can be determined directly by Karl Fischer titration. This

[Hydroxylamine conversion by anammox enrichment].

PubMed

Hu, Anhui; Zheng, Ping; Lu, Huifeng; Ding, Shuang; Wang, Caihua

2010-04-01

Hydroxylamine is an important intermediate product of anammox. This study was focused on the characteristics of hydroxylamine and nitrite conversions by anammox enrichment. The changes of nitrogenous substrates and related products with time were measured using batch tests with anammox enrichment as inoculum. Since hydroxylamine didn't react with nitrite in uninoculated control culture, these two compounds were chemically stable. Both of them decreased with time in anammox enrichment inoculated cultures, in which ammonia as intermediate product would be produced and converted with the maximum concentration being 0.338 mg/L. The total nitrogen concentration decreased from 4.694 mmol/L to 0.812 mmol/L with conversion rate 82.7% in the end. When hydroxylamine and nitrite concentrations were about 2.5 mmol/L respectively, the maximum specific sludge conversion rates of hydroxylamine was 0.535 mmol/(gVSS.h), which was 1.81 times bigger than that of ammonia in ammonia reaction system; the maximum specific sludge rate of total nitrogen was slightly higher than that in ammonia reaction system. When hydroxylamine concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 26.7% and 120.7% respectively; and the maximum ammonia accumulated was 1.810 mmol/L. When nitrite concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 6.9% and 9.0% respectively; and the maximum ammonia accumulated was 0.795 mmol/L. Anammox enrichment was capable of converting hydroxylamine and nitrite simultaneously and had the higher conversion rate of hydroxylamine than ammonia conversion rate. Hydroxylamine and nitrite conversion rates were less affected by increase in nitrite concentration, but more significantly influenced by increase in hydroxylamine. The maximum ammonia concentration accumulated would rise as the result of increasing both hydroxylamine and nitrite. The result of experiment was consistent with pathway model presented by van de Graaf AA.

HAN-Based Monopropellant Propulsion System with Applications

NASA Technical Reports Server (NTRS)

Jankovsky, Robert S.; Oleson, Steven R.

1997-01-01

NASA is developing a new monopropellant propulsion system for small, cost-driven spacecraft with AV requirements in the range of 10-150 m/sec. This system is based on a hydroxylammonium nitrate (HAN)/water/fuel monopropellant blend which is extremely dense, environmentally benign, and promises good performance and simplicity. State-of-art (SOA) small spacecraft typically employ either hydrazine or high pressure stored gas. Herein, a 'typical' small satellite bus is used to illustrate how a HAN-based monopropellant propulsion system fulfills small satellite propulsion requirements by providing mass and/or volume savings of SOA hydrazine monopropellants with the cost benefits of a stored nitrogen gas.

Why Orange Guaymas Basin Beggiatoa spp. Are Orange: Single-Filament-Genome-Enabled Identification of an Abundant Octaheme Cytochrome with Hydroxylamine Oxidase, Hydrazine Oxidase, and Nitrite Reductase Activities

PubMed Central

Biddle, Jennifer F.; Siebert, Jason R.; Staunton, Eric; Hegg, Eric L.; Matthysse, Ann G.; Teske, Andreas

2013-01-01

Orange, white, and yellow vacuolated Beggiatoaceae filaments are visually dominant members of microbial mats found near sea floor hydrothermal vents and cold seeps, with orange filaments typically concentrated toward the mat centers. No marine vacuolate Beggiatoaceae are yet in pure culture, but evidence to date suggests they are nitrate-reducing, sulfide-oxidizing bacteria. The nearly complete genome sequence of a single orange Beggiatoa (“Candidatus Maribeggiatoa”) filament from a microbial mat sample collected in 2008 at a hydrothermal site in Guaymas Basin (Gulf of California, Mexico) was recently obtained. From this sequence, the gene encoding an abundant soluble orange-pigmented protein in Guaymas Basin mat samples (collected in 2009) was identified by microcapillary reverse-phase high-performance liquid chromatography (HPLC) nano-electrospray tandem mass spectrometry (μLC–MS-MS) of a pigmented band excised from a denaturing polyacrylamide gel. The predicted protein sequence is related to a large group of octaheme cytochromes whose few characterized representatives are hydroxylamine or hydrazine oxidases. The protein was partially purified and shown by in vitro assays to have hydroxylamine oxidase, hydrazine oxidase, and nitrite reductase activities. From what is known of Beggiatoaceae physiology, nitrite reduction is the most likely in vivo role of the octaheme protein, but future experiments are required to confirm this tentative conclusion. Thus, while present-day genomic and proteomic techniques have allowed precise identification of an abundant mat protein, and its potential activities could be assayed, proof of its physiological role remains elusive in the absence of a pure culture that can be genetically manipulated. PMID:23220958

40 CFR 721.2083 - Polysubstituted carbomonocyclic hydroxylamine (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... hydroxylamine (generic). 721.2083 Section 721.2083 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2083 Polysubstituted carbomonocyclic hydroxylamine (generic). (a... generically as a polysubstituted carbomonocyclic hydroxylamine (PMN P-97-878) is subject to reporting under...

Hydroxylamine addition impact to Nitrosomonas europaea activity in the presence of monochloramine

EPA Science Inventory

In drinking water, monochloramine may promote ammonia–oxidizing bacteria (AOB) growth because of concurrent ammonia presence. AOB use (i) ammonia monooxygenase for biological ammonia oxidation to hydroxylamine and (ii) hydroxylamine oxidoreductase for hydroxylamine oxidation to ...

Simultaneous determination of hydroxylamine and phenol using a nanostructure-based electrochemical sensor.

PubMed

Moghaddam, Hadi Mahmoudi; Beitollahi, Hadi; Tajik, Somayeh; Malakootian, Mohammad; Maleh, Hassan Karimi

2014-11-01

The electrochemical oxidation of hydroxylamine on the surface of a carbon paste electrode modified with carbon nanotubes and 2,7-bis(ferrocenyl ethyl)fluoren-9-one is studied. The electrochemical response characteristics of the modified electrode toward hydroxylamine and phenol were investigated. The results showed an efficient catalytic activity of the electrode for the electro-oxidation of hydroxylamine, which leads to lowering its overpotential. The modified electrode exhibits an efficient electron-mediating behavior together with well-separated oxidation peaks for hydroxylamine and phenol. Also, the modified electrode was used for determination of hydroxylamine and phenol in some real samples.

The kinetics for ammonium and nitrite oxidation under the effect of hydroxylamine.

PubMed

Wan, Xinyu; Xiao, Pengying; Zhang, Daijun; Lu, Peili; Yao, Zongbao; He, Qiang

2016-01-01

The kinetics for ammonium (NH4(+)) oxidation and nitrite (NO2(-)) oxidation under the effect of hydroxylamine (NH2OH) were studied by respirometry using the nitrifying sludge from a laboratory-scale sequencing batch reactor. Modified models were used to estimate kinetics parameters of ammonia and nitrite oxidation under the effect of hydroxylamine. An inhibition effect of hydroxylamine on the ammonia oxidation was observed under different hydroxylamine concentration levels. The self-inhibition coefficient of hydroxylamine oxidation and noncompetitive inhibition coefficient of hydroxylamine for nitrite oxidation was estimated by simulating exogenous oxygen-uptake rate profiles, respectively. The inhibitive effect of NH2OH on nitrite-oxidizing bacteria was stronger than on ammonia-oxidizing bacteria. This work could provide fundamental data for the kinetic investigation of the nitrification process.

The steady-state kinetics of the NADH-dependent nitrite reductase from Escherichia coli K 12. Nitrite and hydroxylamine reduction.

PubMed Central

Jackson, R H; Cole, J A; Cornish-Bowden, A

1981-01-01

The reduction of both NO2- and hydroxylamine by the NADH-dependent nitrite reductase of Escherichia coli K 12 (EC 1.6.6.4) appears to follow Michaelis-Menten kinetics over a wide range of NADH concentrations. Substrate inhibition can, however, be detected at low concentrations of the product NAD+. In addition, NAD+ displays mixed product inhibition with respect to NADH and mixed or uncompetitive inhibition with respect to hydroxylamine. These inhibition characteristics are consistent with a mechanism in which hydroxylamine binds during catalysis to a different enzyme form from that generated when NAD+ is released. The apparent maximum velocity with NADH as varied substrate increases as the NAD+ concentration increases from 0.05 to 0.7 mM with 1 mM-NO2- or 100 mM-hydroxylamine as oxidized substrate. This increase is more marked for hydroxylamine reduction than for NO2- reduction. Models incorporating only one binding site for NAD can account for the variation in the Michaelis-Menten parameters for both NADH and hydroxylamine with [NAD+] for hydroxylamine reduction. According to these models, activation of the reaction occurs by reversal of an over-reduction of the enzyme by NADH. If the observed activation of the enzyme by NAD+ derives both from activation of the generation of the enzyme-hydroxylamine complex from the enzyme-NO2- complex during NO2- reduction and from activation of the reduction of the enzyme-hydroxylamine complex to form NH4+, then the variation of Vapp. for NO2- or hydroxylamine with [NAD+] is consistent with the occurrence of the same enzyme-hydroxylamine complex as an intermediate in both reactions. PMID:6279095

40 CFR 721.4420 - Substituted hydroxylamine.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted hydroxylamine. 721.4420... Substances § 721.4420 Substituted hydroxylamine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydroxylamine (PMN P-84-492) is...

Method for dissolving delta-phase plutonium

DOEpatents

Karraker, David G.

1992-01-01

A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.

Nontoxic Hydroxylammonium Nitrate (HAN) Monopropellant Propulsion

NASA Technical Reports Server (NTRS)

McKechnie, Timothy N.

2015-01-01

Nontoxic monopropellants have been developed that provide better performance than toxic hydrazine. Formulations based on HAN have superior performance as compared to hydrazine with enhanced specific impulse (Isp), higher density and volumetric impulse, lower melting point, and much lower toxicity. However, HAN-based monopropellants require higher chamber temperatures (2,083 K vs. 883 K) to combust. Current hydrazine-based combustion chamber technology (Inconel® or niobium C103 and silicide coating) and catalyst (Shell 405) are inadequate. In Phase I, state-of-the-art iridium-lined rhenium chambers and innovative new foam catalysts were demonstrated in pulse and 10-second firings. Phase II developed and tested a flight-weight thruster for an environmentally green monopropellant.

HAN (Hydroxylammonium Nitrate) Based Liquid Gun Propellants: Physical Properties

DTIC Science & Technology

1987-11-01

are obsolete UNCLASSIF IED UNCLASS IF IED 18. SUBJECT TERMS (con’t) Triethanolammonium Nitrate TEAN 19. ABSTRACT (con’t) The effect of the molecular...were synthesized and their viscosities and nsi1t9 deter,-ine.0d as a function of temperature. The results clearly show the effects of hydrogen bonding...on the physical properties. Surface tension and vapor pressure have been determined and an equation of state that accurately describes the effect of

Carbon Monoxide-Reacting Pigment from Desulfotomaculum nigrificans and Its Possible Relevance to Sulfite Reduction

PubMed Central

Trudinger, P. A.

1970-01-01

The separation of an autoxidizable brown pigment, P582, from Desulfotomaculum nigrificans is described. It reacted with Na2S2O4 and was characterized by absorption maxima in the oxidized state at 392, 582, and 700 nm. In the presence of Na2S2O4, P582 formed complexes with CO and, under alkaline conditions, pyridine. There was no reaction with cyanide. The molecular weight of P582 was approximately 145,000, and the purest preparations contained Fe, Zn, and acid-labile sulfide but not Cu, Mo, or Mn. Preparations of P582 catalyzed the reduced methyl viologen (MVH)-linked reduction of sulfite, hydroxylamine, and nitrite but not of sulfate, thiosulfate, or nitrate. Reduced pyridine nucleotides did not substitute for MVH. A major product of the MVH-sulfite reaction was sulfide. CO partially inhibited the enzymatic activities. Sulfite, hydroxylamine, and nitrite and CO caused changes in the spectrum of Na2S2O4-reduced P582. Fe2+-chelating reagents reacted with part of the Fe of P582 and caused partial losses of labile sulfide and enzymatic activity. The spectral and CO-reacting properties of P582 were, however, unaffected by chelating agents. The reaction between P582 and chelating agents was stimulated by reducing agents. PMID:5473884

Electroless growth of silver nanoparticles into mesostructured silica block copolymer films.

PubMed

Bois, Laurence; Chassagneux, Fernand; Desroches, Cédric; Battie, Yann; Destouches, Nathalie; Gilon, Nicole; Parola, Stéphane; Stéphan, Olivier

2010-06-01

Silver nanoparticles and silver nanowires have been grown inside mesostructured silica films obtained from block copolymers using two successive reduction steps: the first one involves a sodium borohydride reduction or a photoreduction of silver nitrate contained in the film, and the second one consists of a silver deposit on the primary nanoparticles, carried out by silver ion solution reduction with hydroxylamine chloride. We have demonstrated that the F127 block copolymer ((PEO)(106)(PPO)(70)(PEO)(106)), "F type", mesostructured silica film is a suitable "soft" template for the fabrication of spherical silver nanoparticles arrays. Silver spheres grow from 7 to 11 nm upon the second reduction step. As a consequence, a red shift of the surface plasmon resonance associated with metallic silver has been observed and attributed to plasmonic coupling between particles. Using a P123 block copolymer ((PEO)(20)(PPO)(70)(PEO)(20)), "P type", mesostructured silica film, we have obtained silver nanowires with typical dimension of 10 nm x 100 nm. The corresponding surface plasmon resonance is blue-shifted. The hydroxylamine chloride treatment appears to be efficient only when a previous chemical reduction is performed, assuming that the first sodium borohydride reduction induces a high concentration of silver nuclei in the first layer of the porous silica (film/air interface), which explains their reactivity for further growth.

HAN-Based Monopropellant Technology Development

NASA Technical Reports Server (NTRS)

Reed, Brian

2002-01-01

NASA Glenn Research Center is sponsoring efforts to develop technology for high-performance, high-density, low-freezing point, low-hazards monopropellant systems. The program is focused on a family of monopropellant formulations composed of an aqueous solution of hydroxylammonium nitrate (HAN) and a fuel component. HAN-based monopropellants offer significant mass and volume savings to small (less than 100 kg) satellite for orbit raising and on-orbit propulsion applications. The low-hazards characteristics of HAN-based monopropellants make them attractive for applications where ground processing costs are a significant concern. A 1-lbf thruster has been demonstrated to a 20-kg satellite orbit insertion duty cycle, using a formulation compatible with currently available catalysts. To achieve specific impulse levels above those of hydrazine, catalyst materials that can withstand the high-temperature, corrosive combustion environment of HAN-based monopropellants have to be developed. There also needs to be work done to characterize propellant properties, burning behavior, and material compatibility. NASA is coordinating their monopropellant efforts with those of the United States Air Force.

Three transcription regulators of the Nss family mediate the adaptive response induced by nitrate, nitric oxide or nitrous oxide in Wolinella succinogenes.

PubMed

Kern, Melanie; Simon, Jörg

2016-09-01

Sensing potential nitrogen-containing respiratory substrates such as nitrate, nitrite, hydroxylamine, nitric oxide (NO) or nitrous oxide (N2 O) in the environment and subsequent upregulation of corresponding catabolic enzymes is essential for many microbial cells. The molecular mechanisms of such adaptive responses are, however, highly diverse in different species. Here, induction of periplasmic nitrate reductase (Nap), cytochrome c nitrite reductase (Nrf) and cytochrome c N2 O reductase (cNos) was investigated in cells of the Epsilonproteobacterium Wolinella succinogenes grown either by fumarate, nitrate or N2 O respiration. Furthermore, fumarate respiration in the presence of various nitrogen compounds or NO-releasing chemicals was examined. Upregulation of each of the Nap, Nrf and cNos enzyme systems was found in response to the presence of nitrate, NO-releasers or N2 O, and the cells were shown to employ three transcription regulators of the Crp-Fnr superfamily (homologues of Campylobacter jejuni NssR), designated NssA, NssB and NssC, to mediate the upregulation of Nap, Nrf and cNos. Analysis of single nss mutants revealed that NssA controls production of the Nap and Nrf systems in fumarate-grown cells, while NssB was required to induce the Nap, Nrf and cNos systems specifically in response to NO-generators. NssC was indispensable for cNos production under any tested condition. The data indicate dedicated signal transduction routes responsive to nitrate, NO and N2 O and imply the presence of an N2 O-sensing mechanism. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Shewanella oneidensis cytochrome c nitrite reductase (ccNiR) does not disproportionate hydroxylamine to ammonia and nitrite, despite a strongly favorable driving force.

PubMed

Youngblut, Matthew; Pauly, Daniel J; Stein, Natalia; Walters, Daniel; Conrad, John A; Moran, Graham R; Bennett, Brian; Pacheco, A Andrew

2014-04-08

Cytochrome c nitrite reductase (ccNiR) from Shewanella oneidensis, which catalyzes the six-electron reduction of nitrite to ammonia in vivo, was shown to oxidize hydroxylamine in the presence of large quantities of this substrate, yielding nitrite as the sole free nitrogenous product. UV-visible stopped-flow and rapid-freeze-quench electron paramagnetic resonance data, along with product analysis, showed that the equilibrium between hydroxylamine and nitrite is fairly rapidly established in the presence of high initial concentrations of hydroxylamine, despite said equilibrium lying far to the left. By contrast, reduction of hydroxylamine to ammonia did not occur, even though disproportionation of hydroxylamine to yield both nitrite and ammonia is strongly thermodynamically favored. This suggests a kinetic barrier to the ccNiR-catalyzed reduction of hydroxylamine to ammonia. A mechanism for hydroxylamine reduction is proposed in which the hydroxide group is first protonated and released as water, leaving what is formally an NH2(+) moiety bound at the heme active site. This species could be a metastable intermediate or a transition state but in either case would exist only if it were stabilized by the donation of electrons from the ccNiR heme pool into the empty nitrogen p orbital. In this scenario, ccNiR does not catalyze disproportionation because the electron-donating hydroxylamine does not poise the enzyme at a sufficiently low potential to stabilize the putative dehydrated hydroxylamine; presumably, a stronger reductant is required for this.

Role of Reversible Histidine Coordination in Hydroxylamine Reduction by Plant Hemoglobins (Phytoglobins).

PubMed

Athwal, Navjot Singh; Alagurajan, Jagannathan; Andreotti, Amy H; Hargrove, Mark S

2016-10-18

Reduction of hydroxylamine to ammonium by phytoglobin, a plant hexacoordinate hemoglobin, is much faster than that of other hexacoordinate hemoglobins or pentacoordinate hemoglobins such as myoglobin, leghemoglobin, and red blood cell hemoglobin. The reason for differences in reactivity is not known but could be intermolecular electron transfer between protein molecules in support of the required two-electron reduction, hydroxylamine binding, or active site architecture favoring the reaction. Experiments were conducted with phytoglobins from rice, tomato, and soybean along with human neuroglobin and soybean leghemoglobin that reveal hydroxylamine binding as the rate-limiting step. For hexacoordinate hemoglobins, binding is limited by the dissociation rate constant for the distal histidine, while leghemoglobin is limited by an intrinsically low affinity for hydroxylamine. When the distal histidine is removed from rice phytoglobin, a hydroxylamine-bound intermediate is formed and the reaction rate is diminished, indicating that the distal histidine imidazole side chain is critical for the reaction, albeit not for electron transfer but rather for direct interaction with the substrate. Together, these results demonstrate that phytoglobins are superior at hydroxylamine reduction because they have distal histidine coordination affinity constants near 1, and facile rate constants for binding and dissociation of the histidine side chain. Hexacoordinate hemoglobins such as neuroglobin are limited by tighter histidine coordination that blocks hydroxylamine binding, and pentacoordinate hemoglobins have intrinsically lower hydroxylamine affinities.

A Simple and Direct LC-MS Method for Determination of Genotoxic Impurity Hydroxylamine in Pharmaceutical compounds.

PubMed

Kumar, Thangarathinam; Ramya, Mohandass; Srinivasan, Viswanathan; Xavier, N

2017-08-01

Hydroxylamine is a known genotoxic impurity compound that needs to be controlled down to ppm level in pharmaceutical processes. It is difficult to detect using conventional analytical techniques due to its physio-chemical properties like lack of chromophore, low molecular weight, absence of carbon atom and high polarity. In addition to that, analysis of the pharmaceutical samples encounters considerable obstruction from matrix components that greatly overshadow the response of hydroxylamine. This study describes a simple, sensitive and direct Liquid Chromatographic-Mass Spectrometric method (LC-MS) for detection of hydroxylamine in pharmaceutical compounds. The LC-MS method was detected up to 0.008 ppm of hydroxylamine with S/N > 3.0 and quantified up to 0.025 ppm of hydroxylamine with S/N ratio >10.0. This validated method can be applied as a generic method to detect the hydroxylamine for pharmaceutical process control and drug substance release. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The history of cholinesterase reactivation: hydroxylamine and pyridinium aldoximes.

PubMed

Petroianu, G A

2012-10-01

Hydroxylamine (NH2OH) the substance which will turn out to be of importance to those interested in the treatment of organophosporus cholinesterase inhibitor exposure, was synthesized by Wilhem Clemens Lossen in 1865 while working in Halle as an assistant in the laboratory of Wilhelm Heinrich Heintz. The Lossen synthesis generated hydroxylamine in aqueous solution. Anhydrous hydroxylamine was prepared almost simultaneously by Lobry de Bruyn and Crismer (1891). Using hydroxylamine as a starting point Meyer synthesized aldoximes and ketoximes (1897). Lange, a PhD student of Ladenburg, isolated 2-methyl-pyridine (alpha-picoline). Some fifty years later Wilson, working in the laboratory of Nachmansohn, demonstrated the ability of hydroxylamine to reactivate cholinesterase inhibited by organophosphates. Finally Wilson and Ginsburg using 2-methyl-pyridine as a starting point synthesized the first pyridinium aldoxime reactivator of clinical relevance, pralidoxime (1955).

Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit

PubMed Central

2014-01-01

Background The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. Results We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Conclusions Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning. PMID:24708438

Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

PubMed

Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

2014-04-04

The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

Formation yields of C8 1,4-hydroxycarbonyls from OH + n-octane in the presence of NO.

PubMed

Aschmann, Sara M; Arey, Janet; Atkinson, Roger

2012-12-18

1,4-Hydroxycarbonyls are major products of the OH radical-initiated reactions of ≥ C₅ n-alkanes in the presence of NO. However, because of a lack of commercially available standards of 1,4-hydroxycarbonyls and difficulties in using gas chromatography for their analysis without prior derivatization, quantification of 1,4-hydroxycarbonyls in OH + alkane reactions has proven difficult. We have used an annular denuder coated with XAD resin and further coated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine for in situ derivatization of the 1,4-hydroxycarbonyls formed from the OH + n-octane reaction in the presence of NO. Quantification was achieved by using 2,5-hexanedione as an internal standard. Formation yields for (7-hydroxy-4-octanone + 6-hydroxy-3-octanone + 5-hydroxy-2-octanone) and of 4-hydroxyoctanal of 61 ± 11% and 2.1 ± 0.5%, respectively, were obtained. When combined with previously measured or estimated formation yields for octyl nitrates and hydroxyoctyl nitrates, 93 ± 15% of the overall reaction products are accounted for, indicating that no additional reaction pathways remain to be identified.

Cascade rearrangement of furylcarbinols with hydroxylamines: practical access to densely functionalized cyclopentane derivatives.

PubMed

Veits, Gesine K; Wenz, Donald R; Palmer, Leoni I; St Amant, André H; Hein, Jason E; Read de Alaniz, Javier

2015-08-21

This article describes the aza-Piancatelli rearrangement with hydroxylamines to 4-aminocyclopentenones and subsequent transformations that highlight the versatility of the cyclopentene scaffold and the value of the hydroxylamine nucleophile in this transformation.

Synthesis and Evaluation of Curcuminoid Analogues as Antioxidant and Antibacterial Agents.

PubMed

Emam, Dalia R; Alhajoj, Ahmad M; Elattar, Khaled M; Kheder, Nabila A; Fadda, Ahmed A

2017-06-11

Diazocoupling reaction of curcumin with different diazonium salts of p -toluidine, 2-aminopyridine, and 4-aminoantipyrine in pyridine yielded the arylhydrazones 2a - c . Arylhydrazone of p -toluidine reacted with urea, thiourea, and guanidine nitrate to produce 5,6-dihydropyrimidines. Further reaction of 2a with 2,3-diaminopyrdine in sodium ethoxide solution yielded 1 H -pyrido[2,3- b ][1,4]diazepine derivative. Bis (2,5-dihydroisoxazole) is obtained from the reaction of 2a with hydroxylamine hydrochloride, while its reactions with hydrazines afforded the respective 4,5-dihydro-1 H -pyrazoles. The target compounds were evaluated as antioxidant and antibacterial agents. The tested compounds showed good to moderate activities compared to ascorbic acid and chloramphenicol, respectively.

Human cytochrome-P450 enzymes metabolize N-(2-methoxyphenyl)hydroxylamine, a metabolite of the carcinogens o-anisidine and o-nitroanisole, thereby dictating its genotoxicity.

PubMed

Naiman, Karel; Martínková, Markéta; Schmeiser, Heinz H; Frei, Eva; Stiborová, Marie

2011-12-24

N-(2-Methoxyphenyl)hydroxylamine is a component in the human metabolism of two industrial and environmental pollutants and bladder carcinogens, viz. 2-methoxyaniline (o-anisidine) and 2-methoxynitrobenzene (o-nitroanisole), and it is responsible for their genotoxicity. Besides its capability to form three deoxyguanosine adducts in DNA, N-(2-methoxyphenyl)-hydroxylamine is also further metabolized by hepatic microsomal enzymes. To investigate its metabolism by human hepatic microsomes and to identify the major microsomal enzymes involved in this process are the aims of this study. N-(2-Methoxyphenyl)hydroxylamine is metabolized by human hepatic microsomes predominantly to o-anisidine, one of the parent carcinogens from which N-(2-methoxyphenyl)hydroxylamine is formed, while o-aminophenol and two N-(2-methoxyphenyl)hydroxylamine metabolites, whose exact structures have not been identified as yet, are minor products. Selective inhibitors of microsomal CYPs, NADPH:CYP reductase and NADH:cytochrome-b(5) reductase were used to characterize human liver microsomal enzymes reducing N-(2-methoxyphenyl)hydroxylamine to o-anisidine. Based on these studies, we attribute the main activity for this metabolic step in human liver to CYP3A4, 2E1 and 2C (more than 90%). The enzymes CYP2D6 and 2A6 also partake in this N-(2-methoxyphenyl)hydroxylamine metabolism in human liver, but only to ∼6%. Among the human recombinant CYP enzymes tested in this study, human CYP2E1, followed by CYP3A4, 1A2, 2B6 and 2D6, were the most efficient enzymes metabolizing N-(2-methoxyphenyl)hydroxylamine to o-anisidine. The results found in this study indicate that genotoxicity of N-(2-methoxyphenyl)hydroxylamine is dictated by its spontaneous decomposition to nitrenium/carbenium ions generating DNA adducts, and by its susceptibility to metabolism by CYP enzymes. Copyright © 2011 Elsevier B.V. All rights reserved.

A Localized Surface Plasmon Resonance Sensing Method for Simultaneous Determination of Atenolol and Amiloride in Pharmaceutical Dosage Forms and Urine Samples

PubMed Central

2018-01-01

This contribution describes a simple, fast, and sensitive application of localized surface plasmon resonance effect of silver nanoparticles for simultaneous determination of antihypertensive drugs' mixture atenolol and amiloride in both pharmaceutical dosage forms and in biological samples (urine). Silver nanoparticles were prepared by chemical reduction of silver nitrate using hydroxylamine HCL in an alkaline medium. Application of silver-hydroxylamine nanoparticles (SH NPs) provides many advantages including reproducibility, sensitivity, and cost effective way of analyte determination. Amiloride has four amino groups which act as attachment points on the surface of silver nanoparticles resulting in a synergistic effect on the absorption intensity of atenolol, leading to increase the sensitivity of the determination of both compounds. This method shows excellent advantages comparing with the previously reported methods, including accuracy, precision, and selectivity. The linear range of atenolol is 1 × 10−5–1 × 10−4 mol·L−1 and of amiloride is 1 × 10−6–1 × 10−5 mol·L−1. The limit of detection (LOD) values of atenolol and amiloride are 0.89 × 10−5 and 0.42 × 10−6 mol·L−1, respectively. PMID:29576886

Helping HAN for hybrid rockets

NASA Astrophysics Data System (ADS)

Ramohalli, Kumar; Dowler, Warren

1995-01-01

Hydroxyl amine nitrate (HAN) is a powerful oxidizer for hybrid rocket flight motors. Miscible with water up to 95% by mass, it also has high density and has been extensively characterized for materials compatibility, safety, transportation, storage and handling. Before any serious attempt to use the proposed oxidizer in hybrids, though, the usual performance figures must first be obtained. The simplest are time-independent, equilibrium rocket performance numbers that include chamber temperature, temperature at the nozzle throat, and key species in the exhaust. These numbers must be followed by several other important performance evaluation, including burning rates, pressure dependence, susceptibility to instabilities and temperature sensitivity.

Advanced Monopropellant Thruster Technology Tested

NASA Technical Reports Server (NTRS)

Reed, Brian D.

2000-01-01

A new family of environmentally friendly, low-freezing-point, high-density monopropellants is being developed under a NASA Glenn technology program. New monopropellant technology would greatly benefit a range of small (<100 kg) satellites and spacecraft missions. These monopropellants are mixtures of hydroxylammonium nitrate (HAN), fuel, and water. Primex Aerospace Company, under contract to the NASA Glenn Research Center at Lewis Field, tested a 1-lbf thruster using a HAN-based monopropellant formulation. Over 8000 sec of total test time was accumulated on a single thruster using the blowdown duty cycle typical of state-of-the-art monopropellant systems.

Sensitive detection of hydroxylamine at a simple baicalin carbon nanotubes modified electrode.

PubMed

Zhang, Hongfang; Zheng, Jianbin

2012-05-15

A baicalin multi-wall carbon nanotubes (BaMWCNT) modified glassy carbon electrode (GCE) for the sensitive determination of hydroxylamine was described. The BaMWCNT/GCE with dramatic stability was firstly fabricated with a simple adsorption method. And it showed excellent catalytic activity toward the electrooxidation of hydroxylamine. The amperometric response at the BaMWCNT/GCE modified electrode increased linearly to hydroxylamine concentrations in the range of 0.5 μM to 0.4mM with a detection limit of 0.1 μM. The modified electrode was applied to detection hydroxylamine in the tap water, and the average recovery for the standards added was 96.0%. Copyright © 2012 Elsevier B.V. All rights reserved.

Antioxidant properties of MitoTEMPOL and its hydroxylamine.

PubMed

Trnka, Jan; Blaikie, Frances H; Logan, Angela; Smith, Robin A J; Murphy, Michael P

2009-01-01

Piperidine nitroxides such as TEMPOL have been widely used as antioxidants in vitro and in vivo. MitoTEMPOL is a mitochondria-targeted derivative of TEMPOL designed to protect mitochondria from the oxidative damage that they accumulate, but once there is rapidly reduced to its hydroxylamine, MitoTEMPOL-H. As little is known about the antioxidant efficacy of hydroxylamines, this study has assessed the antioxidant activity of both MitoTEMPOL and MitoTEMPOL-H. The hydroxylamine was more effective at preventing lipid-peroxidation than MitoTEMPOL and decreased oxidative damage to mitochondrial DNA caused by menadione. In contrast to MitoTEMPOL, MitoTEMPOL-H has no superoxide dismutase activity and its antioxidant actions are likely to be mediated by hydrogen atom donation. Therefore, even though MitoTEMPOL is rapidly reduced to MitoTEMPOL-H in cells, it remains an effective antioxidant. Furthermore, as TEMPOL is also reduced to a hydroxylamine in vivo, many of its antioxidant effects may also be mediated by its hydroxylamine.

Hydroxylamine technique for in vitro prevention of penicillin inactivation of tobramycin.

PubMed Central

Falkowski, A J; Creger, R J

1984-01-01

Hydroxylamine was evaluated and found to be a highly effective agent for the in vitro prevention of penicillin inactivation of tobramycin. This inactivation reaction resulted in an underestimation of tobramycin concentrations and was dependent on time, temperature, amount and type of penicillin, and amount of tobramycin. Plasma samples containing tobramycin and three clinically relevant concentrations of ticarcillin, carbenicillin, azlocillin, or piperacillin were incubated with and without hydroxylamine, and tobramycin concentrations were monitored at 0, 12, 24, 48, and 72 h. The inactivation reaction was found to be completely inhibited by hydroxylamine (1 mg/ml) compared with a 27 to 50% loss of measured tobramycin concentration in the unprotected tobramycin-penicillin samples. Hydroxylamine did not interfere with the Emit enzyme immunoassay (Syva Co.) at either high or low tobramycin concentrations. Hydroxylamine was effective in inhibiting the tobramycin inactivation at both room and refrigerator temperatures and was 100% effective in protecting tobramycin on a 1:1 molar basis. PMID:6393865

High-Performance Monopropellants and Catalysts Evaluated

NASA Technical Reports Server (NTRS)

Reed, Brian D.

2004-01-01

The NASA Glenn Research Center is sponsoring efforts to develop advanced monopropellant technology. The focus has been on monopropellant formulations composed of an aqueous solution of hydroxylammonium nitrate (HAN) and a fuel component. HAN-based monopropellants do not have a toxic vapor and do not need the extraordinary procedures for storage, handling, and disposal required of hydrazine (N2H4). Generically, HAN-based monopropellants are denser and have lower freezing points than N2H4. The performance of HAN-based monopropellants depends on the selection of fuel, the HAN-to-fuel ratio, and the amount of water in the formulation. HAN-based monopropellants are not seen as a replacement for N2H4 per se, but rather as a propulsion option in their own right. For example, HAN-based monopropellants would prove beneficial to the orbit insertion of small, power-limited satellites because of this propellant's high performance (reduced system mass), high density (reduced system volume), and low freezing point (elimination of tank and line heaters). Under a Glenn-contracted effort, Aerojet Redmond Rocket Center conducted testing to provide the foundation for the development of monopropellant thrusters with an I(sub sp) goal of 250 sec. A modular, workhorse reactor (representative of a 1-lbf thruster) was used to evaluate HAN formulations with catalyst materials. Stoichiometric, oxygen-rich, and fuelrich formulations of HAN-methanol and HAN-tris(aminoethyl)amine trinitrate were tested to investigate the effects of stoichiometry on combustion behavior. Aerojet found that fuelrich formulations degrade the catalyst and reactor faster than oxygen-rich and stoichiometric formulations do. A HAN-methanol formulation with a theoretical Isp of 269 sec (designated HAN269MEO) was selected as the baseline. With a combustion efficiency of at least 93 percent demonstrated for HAN-based monopropellants, HAN269MEO will meet the I(sub sp) 250 sec goal.

Nitrite Formation from Hydroxylamine and Oximes by Pseudomonas aeruginosa

PubMed Central

Amarger, Noelle; Alexander, M.

1968-01-01

Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from the corresponding oximes. The oxime apparently functions as a constant source of hydroxylamine during growth of the bacterium. Hydroxylamine at low concentration was converted stoichiometrically to nitrite by extracts of the bacterium; high concentrations were inhibitory. Nicotinamide adenine dinucleotide phosphate, oxygen, and other unidentified cofactors were necessary for the reaction. Actively nitrifying extracts possessed no hydroxylamine-cytochrome c reductase activity. Hyponitrite, nitrous oxide, and nitric oxide were not metabolized. PMID:4384968

Thermal decomposition pathways of hydroxylamine: theoretical investigation on the initial steps.

PubMed

Wang, Qingsheng; Wei, Chunyang; Pérez, Lisa M; Rogers, William J; Hall, Michael B; Mannan, M Sam

2010-09-02

Hydroxylamine (NH(2)OH) is an unstable compound at room temperature, and it has been involved in two tragic industrial incidents. Although experimental studies have been carried out to study the thermal stability of hydroxylamine, the detailed decomposition mechanism is still in debate. In this work, several density functional and ab initio methods were used in conjunction with several basis sets to investigate the initial thermal decomposition steps of hydroxylamine, including both unimolecular and bimolecular reaction pathways. The theoretical investigation shows that simple bond dissociations and unimolecular reactions are unlikely to occur. The energetically favorable initial step of decomposition pathways was determined as a bimolecular isomerization of hydroxylamine into ammonia oxide with an activation barrier of approximately 25 kcal/mol at the MPW1K level of theory. Because hydroxylamine is available only in aqueous solutions, solvent effects on the initial decomposition pathways were also studied using water cluster methods and the polarizable continuum model (PCM). In water, the activation barrier of the bimolecular isomerization reaction decreases to approximately 16 kcal/mol. The results indicate that the bimolecular isomerization pathway of hydroxylamine is more favorable in aqueous solutions. However, the bimolecular nature of this reaction means that more dilute aqueous solution will be more stable.

Rapid assay for microbially reducible ferric iron in aquatic sediments

USGS Publications Warehouse

Lovely, Derek R.; Philips , Elizabeth J.P.

1987-01-01

The availability of ferric iron for microbial reduction as directly determined by the activity of iron-reducing organisms was compared with its availability as determined by a newly developed chemical assay for microbially reducible iron. The chemical assay was based on the reduction of poorly crystalline ferric iron by hydroxylamine under acidic conditions. There was a strong correlation between the extent to which hydroxylamine could reduce various synthetic ferric iron forms and the susceptibility of the iron to microbial reduction in an enrichment culture of iron-reducing organisms. When sediments that contained hydroxylamine-reducible ferric iron were incubated under anaerobic conditions, ferrous iron accumulated as the concentration of hydroxylamine-reducible ferric iron declined over time. Ferrous iron production stopped as soon as the hydroxylamine-reducible ferric iron was depleted. In anaerobic incubations of reduced sediments that did not contain hydroxylamine-reducible ferric iron, there was no microbial iron reduction, even though the sediments contained high concentrations of oxalate-extractable ferric iron. A correspondence between the presence of hydroxylamine-reducible ferric iron and the extent of ferric iron reduction in anaerobic incubations was observed in sediments from an aquifer and in fresh- and brackish-water sediments from the Potomac River estuary. The assay is a significant improvement over previously described procedures for the determination of hydroxylamine-reducible ferric iron because it provides a correction for the high concentrations of solid ferrous iron which may also be extracted from sediments with acid. This is a rapid, simple technique to determine whether ferric iron is available for microbial reduction.

Double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals: synthesis of bridged isoxazolidines.

PubMed

Yin, Zhiwei; Zhang, Jinzhu; Wu, Jing; Liu, Che; Sioson, Kate; Devany, Matthew; Hu, Chunhua; Zheng, Shengping

2013-07-19

A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed. Moreover, the various functionalities in the isoxazolidine products allow facile derivatization.

A proposed abiotic reaction scheme for hydroxylamine and monochloramine under chloramination relevant drinking water conditions

EPA Science Inventory

Drinking water monochloramine (NH2Cl) use may promote ammonia–oxidizing bacteria (AOB) growth. For biological ammonia (NH3) oxidation, AOB use (i) ammonia monooxygenase for NH3 oxidation to hydroxylamine (NH2OH) and (ii) hydroxylamine oxidoreductase for NH2OH oxidation to nitrit...

FTIR study of the photoreaction of bovine rhodopsin in the presence of hydroxylamine.

PubMed

Katayama, Kota; Furutani, Yuji; Kandori, Hideki

2010-07-15

In bovine rhodopsin, 11-cis-retinal forms a Schiff base linkage with Lys296. The Schiff base is not reactive to hydroxylamine in the dark, which is consistent with the well-protected retinal binding site. In contrast, under illumination it easily forms all-trans retinal oxime, resulting in the loss of color. This suggests that activation of rhodopsin creates a specific reaction channel for hydroxylamine or loosens the chromophore binding pocket. In the present study, to extract structural information on the Schiff base vicinity and to understand the changes upon activation of rhodopsin, we compared light-induced FTIR difference spectra of bovine rhodopsin in the presence and absence of hydroxylamine under physiological pH (approximately 7). Although the previous FTIR study did not observe the complex formation between rhodopsin and G-protein transducin in hydrated films, the present study clearly shows that hydrated films can be used for studies of the interaction between rhodopsin and hydroxylamine. Hydroxylamine does not react with the Schiff base of Meta-I intermediate trapped at 240 K, possibly because of decreased conformational motions under the frozen environment, while FTIR spectroscopy showed that hydroxylamine affects the hydrogen bonds of the Schiff base and water molecules in Meta-I. In contrast, formation of the retinal oxime was clearly observed at 280 K, the characteristic temperature of Meta-II accumulation in the absence of hydroxylamine, and time-dependent formation of retinal oxime was observed from Meta-II at 265 K as well. The obtained difference FTIR spectra of retinal oxime and opsin are different from that of Meta-II. It is likely that the antiparallel beta-sheet constituting a part of the retinal binding pocket at the extracellular surface is structurally disrupted in the presence of hydroxylamine, which allows the hydrolysis of the Schiff base into retinal oxime.

Assessing the reactivation efficacy of hydroxylamine anion towards VX-inhibited AChE: a computational study.

PubMed

Khan, Md Abdul Shafeeuulla; Ganguly, Bishwajit

2012-05-01

Oximate anions are used as potential reactivating agents for OP-inhibited AChE because of they possess enhanced nucleophilic reactivity due to the α-effect. We have demonstrated the process of reactivating the VX-AChE adduct with formoximate and hydroxylamine anions by applying the DFT approach at the B3LYP/6-311 G(d,p) level of theory. The calculated results suggest that the hydroxylamine anion is more efficient than the formoximate anion at reactivating VX-inhibited AChE. The reaction of formoximate anion and the VX-AChE adduct is a three-step process, while the reaction of hydroxylamine anion with the VX-AChE adduct seems to be a two-step process. The rate-determining step in the process is the initial attack on the VX of the VX-AChE adduct by the nucleophile. The subsequent steps are exergonic in nature. The potential energy surface (PES) for the reaction of the VX-AChE adduct with hydroxylamine anion reveals that the reactivation process is facilitated by the lower free energy of activation (by a factor of 1.7 kcal mol(-1)) than that of the formoximate anion at the B3LYP/6-311 G(d,p) level of theory. The higher free energy of activation for the reverse reactivation reaction between hydroxylamine anion and the VX-serine adduct further suggests that the hydroxylamine anion is a very good antidote agent for the reactivation process. The activation barriers calculated in solvent using the polarizable continuum model (PCM) for the reactivation of the VX-AChE adduct with hydroxylamine anion were also found to be low. The calculated results suggest that V-series compounds can be more toxic than G-series compounds, which is in accord with earlier experimental observations.

Influence of hydroxylamine conformation on stereocontrol in Pd-catalyzed isoxazolidine-forming reactions.

PubMed

Lemen, Georgia S; Giampietro, Natalie C; Hay, Michael B; Wolfe, John P

2009-03-20

Palladium-catalyzed carboamination reactions between N-Boc-O-(but-3-enyl)hydroxylamine derivatives and aryl or alkenyl bromides afford cis-3,5- and trans-4,5-disubstituted isoxazolidines in good yield with up to >20:1 dr. The diastereoselectivity observed in the formation of cis-3,5-disubstituted isoxazolidines is superior to selectivities typically obtained in other transformations, such as 1,3-dipolar cycloaddition reactions, that provide these products. In addition, the stereocontrol in the C-N bond-forming Pd-catalyzed carboamination reactions of N-Boc-O-(but-3-enyl)hydroxylamines is significantly higher than that of related C-O bond-forming carboetherification reactions of N-benzyl-N-(but-3-enyl)hydroxylamine derivatives. This is likely due to a stereoelectronic preference for cyclization via transition states in which the Boc group is placed in a perpendicular orientation relative to the plane of the developing ring, which derives from the conformational equilibria of substituted hydroxylamines.

Combustion of Han-Based Monopropellant Droplets in Reduced Gravity

NASA Technical Reports Server (NTRS)

Shaw, B. D.

1999-01-01

The objective of this research is to study combustion of monopropellant droplets and monopropellant droplet components in reduced-gravity environments so that spherical symmetry is strongly promoted. The experiments will use hydroxylammonium nitrate (HAN, chemical formula NH3OHNO3) based monopropellants. This class of monopropellant is selected for study because of its current relevance and also because it is relatively benign and safe to work with. The experimental studies will allow for accurate determination of fundamental data on deflagration rates, gas-phase temperature profiles, transient gas-phase flame behaviors, the onset of bubbling in droplets at lower pressures, and the low-pressure deflagration limit. The theoretical studies will provide rational models of deflagration mechanisms of HAN-based liquid propellants. Besides advancing fundamental knowledge, the proposed research should aid in applications (e.g., spacecraft thrusters and liquid propellant guns) of this unique class of monopropellants.

A simple protocol for NMR analysis of the enantiomeric purity of chiral hydroxylamines.

PubMed

Tickell, David A; Mahon, Mary F; Bull, Steven D; James, Tony D

2013-02-15

A practically simple three-component chiral derivatization protocol for determining the enantiopurity of chiral hydroxylamines by (1)H NMR spectroscopic analysis is described, involving their treatment with 2-formylphenylboronic acid and enantiopure BINOL to afford a mixture of diastereomeric nitrono-boronate esters whose ratio is an accurate reflection of the enantiopurity of the parent hydroxylamine.

Isovanillin derived N-(un)substituted hydroxylamines possessing an ortho-allylic group: valuable precursors to bioactive N-heterocycles.

PubMed

Dulla, Balakrishna; Tangellamudi, Neelima D; Balasubramanian, Sridhar; Yellanki, Swapna; Medishetti, Raghavender; Kumar Banote, Rakesh; Hari Chaudhari, Girish; Kulkarni, Pushkar; Iqbal, Javed; Reiser, Oliver; Pal, Manojit

2014-04-28

The intramolecular 1,3-dipolar cycloaddition of isovanillin derived N-aryl hydroxylamines possessing ortho-allylic dipolarophiles affords novel benzo analogues of tricyclic isoxazolidines that can be readily transformed into functionalized lactams, γ-aminoalcohols and oxazepines. The corresponding N-unsubstituted hydroxylamines give rise to tetrahydroisoquinolines. Anxiogenic properties of these compounds are tested in zebra fish.

GAS-PHASE SYNTHESIS OF PRECURSORS OF INTERSTELLAR GLYCINE: A COMPUTATIONAL STUDY OF THE REACTIONS OF ACETIC ACID WITH HYDROXYLAMINE AND ITS IONIZED AND PROTONATED DERIVATIVES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrientos, Carmen; Redondo, Pilar; Largo, Laura

2012-04-01

A computational study of the reactions of hydroxylamine and its ionized and protonated derivatives with acetic acid is provided. The reaction of neutral hydroxylamine with acetic acid, despite being clearly exothermic, involves a very large energy barrier. The reaction of ionized hydroxylamine with acetic acid is also clearly exothermic, but again a significant energy barrier is found (around 24 kcal mol{sup -1} at the CCSD(T) level). The reaction of the most stable protonated isomer of hydroxylamine, NH{sub 3}OH{sup +}, with acetic acid also involves a high barrier (more than 27 kcal mol{sup -1} at the CCSD(T) level). Only the highermore » energy isomer, NH{sub 2}OH{sup +}{sub 2}, leads to a sensibly lower energy barrier (about 2.3 kcal mol{sup -1} at the CCSD(T) level). Nevertheless, an estimate of the reaction coefficient at low temperatures such as those reigning in the interstellar medium gives very low values. Therefore, it seems that precursors of interstellar glycine could not be efficiently produced from the reactions of hydroxylamine-derived ions with acetic acid.« less

Alkylated hydroxylamine derivatives eliminate peripheral retinylidene Schiff bases but cannot enter the retinal binding pocket of light-activated rhodopsin.

PubMed

Piechnick, Ronny; Heck, Martin; Sommer, Martha E

2011-08-23

Besides Lys-296 in the binding pocket of opsin, all-trans-retinal forms adducts with peripheral lysine residues and phospholipids, thereby mimicking the spectral and chemical properties of metarhodopsin species. These pseudophotoproducts composed of nonspecific retinylidene Schiff bases have long plagued the investigation of rhodopsin deactivation and identification of decay products. We discovered that, while hydroxylamine can enter the retinal binding pocket of light-activated rhodopsin, the modified hydroxylamine compounds o-methylhydroxylamine (mHA), o-ethylhydroxylamine (eHA), o-tert-butylhydroxylamine (t-bHA), and o-(carboxymethyl)hydroxylamine (cmHA) are excluded. However, the alkylated hydroxylamines react quickly and efficiently with exposed retinylidene Schiff bases to form their respective retinal oximes. We further investigated how t-bHA affects light-activated rhodopsin and its interaction with binding partners. We found that both metarhodopsin II (Meta II) and Meta III are resistant to t-bHA, and neither arrestin nor transducin binding is affected by t-bHA. This discovery suggests that the hypothetical solvent channel that opens in light-activated rhodopsin is extremely stringent with regard to size and/or polarity. We believe that alkylated hydroxylamines will prove to be extremely useful reagents for the investigation of rhodopsin activation and decay mechanisms. Furthermore, the use of alkylated hydroxylamines should not be limited to in vitro studies and could help elucidate visual signal transduction mechanisms in the living cells of the retina. © 2011 American Chemical Society

Peculiar properties of photoinduced hydroxylaminolysis in different bacteriorhodopsin-based media using O-substituted hydroxylamines.

PubMed

Dyukova, Tatyana V; Druzhko, Anna B

2010-01-01

The process of photoinduced hydroxylaminolysis has been re-examined in different bacteriorhodopsin (BR)-based media using O-substituted hydroxylamines, in particular, O-(4-nitrobenzyl) hydroxylamine hydrochloride (NBHA), O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride (FBHA) and O-(t-butyl) hydroxylamine hydrochloride (BHA). Both wild type (WT) and D96N BR-based gelatine films and gels were studied. The expected increase in the bleaching rate of BR in gelatin films by using O-substituted hydroxylamines in place of HA was not achieved. On the other hand, it was shown that in gels HA derivatives NBHA and FBHA (as against HA itself) do provide about three- to four-fold higher bleaching rate. By contrast to that in films, D96N BR in gels demonstrates more effective bleaching as compared to WT BR. The plausible interpretation for the results is discussed in frames of reduced mobilities of large-sized molecules of O-substituted hydroxylamines in dehydrated media. FBHA- or NBHA-modified gels possess higher photosensitivity both with D96N and WT BR (as compared with that for HA-modified gels) and offer a potentiality for application as an irreversible-recording medium. As anticipated, it is specifically D96N BR gel modified with FBHA that may present a promising medium suitable for write-once recording thus extending the range of recording materials in the optical processing field. © 2010 The Authors. Journal Compilation. The American Society of Photobiology.

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2013 CFR

2013-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50 mL of the hydroxylamine hydrochloride solution...

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2014 CFR

2014-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50 mL of the hydroxylamine hydrochloride solution...

Electrical Conductivity Measurements of Hydroxylammonium Nitrate: Design Considerations

DTIC Science & Technology

1986-04-01

aqueous NaNO3 i• shown as well to indicate the similarity of this conductivity data with that cf HAN. The solubility of NaNO 3 in H120 is much less than... Wilmot , R-16 Commander Silver Spring, MD 20910 US Army Tank Automotive Command 1 Commander ATTN: AMSTA-TSL Naval Weapons Center Warren, MI 48397-5000

Spectroscopic Characterization of HAN-Based Liquid Gun Propellants and Nitrate Salt Solutions

DTIC Science & Technology

1989-01-15

cables (0.040-in. o.d. x 2.5 ft) consisting of an Inconel sheath containing two nickel / chromium/iron wires that were insulated from each other ser...Subramanlam and M. A. McHugh , I&EC Pruc. Des. Dev. 25, 1 therefore attributed to thermal line broadening instead (1986). of to changes in the equilibrium

Copper-catalyzed one-pot synthesis of 1,2,4-triazoles from nitriles and hydroxylamine.

PubMed

Xu, Hao; Ma, Shuang; Xu, Yuanqing; Bian, Longxiang; Ding, Tao; Fang, Xiaomin; Zhang, Wenkai; Ren, Yanrong

2015-02-06

A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu(OAc)2 as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives.

Heterotrophic nitrogen removal by Acinetobacter sp. Y1 isolated from coke plant wastewater.

PubMed

Liu, YuXiang; Hu, Tingting; Song, Yujie; Chen, Hongping; Lv, YongKang

2015-11-01

A strain of Acinetobacter sp. Y1, which exhibited an amazing ability to remove ammonium, nitrite and nitrate, was isolated from the activated sludge of a coking wastewater treatment plant. The aim of this work was to study the ability, influence factors and possible pathway of nitrogen removal by Acinetobacter sp. Y1. Results showed that maximum removal rate of NH4(+)-N by the strain was 10.28 mg-N/L/h. Carbon source had significant influence on the growth and ammonium removal efficiencies of strain Y1. Pyruvate, citrate and acetate were favourable carbon sources for the strain. Temperature, pH value and shaking speed could affect the growth and nitrogen removal ability. Nitrate or nitrite could be used as a sole nitrogen source for the growth and removed efficiently by the strain. N2 levels increased to 53.74%, 50.21% and 55.13% within 36 h when 100 mg/L NH4(+)-N, NO2(-)-N or NO3(-) -N was used as sole nitrogen source in the gas detection experiment. The activities of hydroxylamine oxidoreductase (HAO), nitrate reductase (NR) and nitrite reductase (NiR), which are key enzymes in heterotrophic nitrification and aerobic denitrification, were all detectable in the strain. Consequently, a possible pathway for ammonium removal by the strain was also suggested. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

15N and13C NMR investigation of hydroxylamine-derivatized humic substances

USGS Publications Warehouse

Thorn, K.A.; Arterburn, J.B.; Mikita, M.A.

1992-01-01

Five fulvic and humic acid samples of diverse origins were derivatized with 15N-labeled hydroxylamine and analyzed by liquid-phase 15N NMR spectrometry. The 15N NMR spectra indicated that hydroxylamine reacted similarly with all samples and could discriminate among carbonyl functional groups. Oximes were the major derivatives; resonances attributable to hydroxamic acids, the reaction products of hydroxylamine with esters, and resonances attributable to the tautomeric equilibrium position between the nitrosophenol and monoxime derivatives of quinones, the first direct spectroscopic evidence for quinones, also were evident. The 15N NMR spectra also suggested the presence of nitriles, oxazoles, oxazolines, isocyanides, amides, and lactams, which may all be explained in terms of Beckmann reactions of the initial oxime derivatives. INEPT and ACOUSTIC 15N NMR spectra provided complementary information on the derivatized samples. 13C NMR spectra of derivatized samples indicated that the ketone/quinone functionality is incompletely derivatized with hydroxylamine. ?? 1991 American Chemical Society.

Electron Paramagnetic Resonance Measurements of Reactive Oxygen Species by Cyclic Hydroxylamine Spin Probes.

PubMed

Dikalov, Sergey I; Polienko, Yuliya F; Kirilyuk, Igor

2018-05-20

Oxidative stress contributes to numerous pathophysiological conditions such as development of cancer, neurodegenerative, and cardiovascular diseases. A variety of measurements of oxidative stress markers in biological systems have been developed; however, many of these methods are not specific, can produce artifacts, and do not directly detect the free radicals and reactive oxygen species (ROS) that cause oxidative stress. Electron paramagnetic resonance (EPR) is a unique tool that allows direct measurements of free radical species. Cyclic hydroxylamines are useful and convenient molecular probes that readily react with ROS to produce stable nitroxide radicals, which can be quantitatively measured by EPR. In this work, we critically review recent applications of various cyclic hydroxylamine spin probes in biology to study oxidative stress, their advantages, and the shortcomings. Recent Advances: In the past decade, a number of new cyclic hydroxylamine spin probes have been developed and their successful application for ROS measurement using EPR has been published. These new state-of-the-art methods provide improved selectivity and sensitivity for in vitro and in vivo studies. Although cyclic hydroxylamine spin probes EPR application has been previously described, there has been lack of translation of these new methods into biomedical research, limiting their widespread use. This work summarizes "best practice" in applications of cyclic hydroxylamine spin probes to assist with EPR studies of oxidative stress. Additional studies to advance hydroxylamine spin probes from the "basic science" to biomedical applications are needed and could lead to better understanding of pathological conditions associated with oxidative stress. Antioxid. Redox Signal. 28, 1433-1443.

Photo-induced bleaching of sensory rhodopsin II (phoborhodopsin) from Halobacterium salinarum by hydroxylamine: identification of the responsible intermediates.

PubMed

Tamogami, Jun; Kikukawa, Takashi; Ikeda, Yoichi; Demura, Makoto; Nara, Toshifumi; Kamo, Naoki

2012-01-05

Sensory rhodopsin II from Halobacterium salinarum (HsSRII) is a retinal protein in which retinal binds to a specific lysine residue through a Schiff base. Here, we investigated the photobleaching of HsSRII in the presence of hydroxylamine. For identification of intermediate(s) attacked by hydroxylamine, we employed the flash-induced bleaching method. In order to change the concentration of intermediates, such as M- and O-intermediates, experiments were performed under varying flashlight intensities and concentrations of azide that accelerated only the M-decay. We found the proportional relationship between the bleaching rate and area under the concentration-time curve of M, indicating a preferential attack of hydroxylamine on M. Since hydroxylamine is a water-soluble reagent, we hypothesize that for M, hydrophilicity or water-accessibility increases specifically in the moiety of Schiff base. Thus, hydroxylamine bleaching rates may be an indication of conformational changes near the Schiff base. We also considered the possibility that azide may induce a small conformational change around the Schiff base. We compared the hydroxylamine susceptibility between HsSRII and NpSRII (SRII from Natronomonas pharaonis) and found that the M of HsSRII is about three times more susceptible than that of the stable NpSRII. In addition, long illumination to HsSRII easily produced M-like photoproduct, P370. We thus infer that the instability of HsSRII under illumination may be related to this increase of hydrophilicity at M and P370. Copyright © 2011 Elsevier B.V. All rights reserved.

Electrocatalytic oxidation of hydrazine and hydroxylamine by graphene oxide-Pd nanoparticle-modified glassy carbon electrode.

PubMed

Lee, Eunhee; Kim, Daekun; You, Jung-Min; Kim, Seul Ki; Yun, Mira; Jeon, Seungwon

2012-12-01

Pd nanoparticle catalysts supported by thiolated graphene oxide (tGO) on a glassy carbon electrode (GCE), and denoted as tGO-Pd/GCE, are used in this study for the electrochemical determination of hydroxylamine and hydrazine. The physicochemical properties of tGO-Pd were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). They showed strong catalytic activity toward the oxidation of hydroxylamine and hydrazine. Cyclic voltammetry (CV) and amperometry were used to characterize the sensors' performances. The detection limits of hydroxylamine and hydrazine by tGO-Pd/GCE were 0.31 and 0.25 microM (s/n = 3), respectively. The sensors' sensitivity, selectivity, and stability were also investigated.

Infrared multiple photon dissociation spectroscopy of group I and group II metal complexes with Boc-hydroxylamine.

PubMed

Dain, Ryan P; Gresham, Gary; Groenewold, Gary S; Steill, Jeffrey D; Oomens, Jos; Van Stipdonk, Michael J

2013-08-30

Hydroxamates are essential growth factors for some microbes, acting primarily as siderophores that solubilize iron for transport into a cell. Here we determined the intrinsic structure of 1:1 complexes between Boc-protected hydroxylamine and group I ([M(L)](+)) and group II ([M(L-H)](+)) cations, where M and L are the cation and ligand, respectively, which are convenient models for the functional unit of hydroxamate siderphores. The relevant complex ions were generated by electrospray ionization (ESI) and isolated and stored in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Infrared spectra of the isolated complexes were collected by monitoring (infrared) photodissociation yield as a function of photon energy. Experimental spectra were then compared to those predicted by density functional theory (DFT) calculations. The infrared multiple photon dissociation (IRMPD) spectra collected are in good agreement with those predicted to be lowest-energy by DFT. The spectra for the group I complexes contain six resolved absorptions that can be attributed to amide I and II type and hydroxylamine N-OH vibrations. Similar absorptions are observed for the group II cation complexes, with shifts of the amide I and amide II vibrations due to the change in structure with deprotonation of the hydroxylamine group. IRMPD spectroscopy unequivocally shows that the intrinsic binding mode for the group I cations involves the O atoms of the amide carbonyl and hydroxylamine groups of Boc-hydroxylamine. A similar binding mode is preferred for the group II cations, except that in this case the metal ion is coordinated by the O atom of the deprotonated hydroxylamine group. Copyright © 2013 John Wiley & Sons, Ltd.

Efficient surface formation route of interstellar hydroxylamine through NO hydrogenation. II. The multilayer regime in interstellar relevant ices

NASA Astrophysics Data System (ADS)

Fedoseev, G.; Ioppolo, S.; Lamberts, T.; Zhen, J. F.; Cuppen, H. M.; Linnartz, H.

2012-08-01

Hydroxylamine (NH2OH) is one of the potential precursors of complex pre-biotic species in space. Here, we present a detailed experimental study of hydroxylamine formation through nitric oxide (NO) surface hydrogenation for astronomically relevant conditions. The aim of this work is to investigate hydroxylamine formation efficiencies in polar (water-rich) and non-polar (carbon monoxide-rich) interstellar ice analogues. A complex reaction network involving both final (N2O, NH2OH) and intermediate (HNO, NH2O., etc.) products is discussed. The main conclusion is that hydroxyl-amine formation takes place via a fast and barrierless mechanism and it is found to be even more abundantly formed in a water-rich environment at lower temperatures. In parallel, we experimentally verify the non-formation of hydroxylamine upon UV photolysis of NO ice at cryogenic temperatures as well as the non-detection of NC- and NCO-bond bearing species after UV processing of NO in carbon monoxide-rich ices. Our results are implemented into an astrochemical reaction model, which shows that NH2OH is abundant in the solid phase under dark molecular cloud conditions. Once NH2OH desorbs from the ice grains, it becomes available to form more complex species (e.g., glycine and β-alanine) in gas phase reaction schemes.

Effect of hydroxylamine on photon-like events during dark adaptation in toad rod photoreceptors.

PubMed Central

Leibrock, C S; Lamb, T D

1997-01-01

1. The suction pipette technique was used to investigate the recovery of toad rod photoreceptors following small bleaches of 0.2-3% of the rhodopsin. 2. The reduction in sensitivity and the increase in noise elicited by bleaches were measured, and from these measurements the underlying rate of occurrence of photon-like events was calculated as a function of time after the bleach. 3. Exposure to hydroxylamine solution was used to hasten the decomposition of the metarhodopsin photoproducts. The outer segment was exposed to 110 mM hydroxylamine in a low-Ca2+ Ringer solution for a period of 10-50 s beginning 10-17 min after the bleaching exposure. 4. By the time of the hydroxylamine exposure, the flash sensitivity and response kinetics had returned almost to normal, and were not significantly altered by the exposure. 5. Following hydroxylamine exposure, the rate of spontaneous photon-like events in the rods declined rapidly to near pre-bleach levels. 6. We conclude that hydroxylamine reduces the rate of occurrence of photon-like events induced by a bleach, and we postulate that this reduction results from the removal of metarhodopsin (most likely metarhodopsin II) from the outer segment. 7. Our results are consistent with a model in which photon-like events result from reversal of the reactions (phosphorylation and capping by arrestin) that lead to inactivation of the activated form of rhodopsin, Rh*. PMID:9174997

On-Board Chemical Propulsion Technology

NASA Technical Reports Server (NTRS)

Reed, Brian D.

2004-01-01

On-board propulsion functions include orbit insertion, orbit maintenance, constellation maintenance, precision positioning, in-space maneuvering, de-orbiting, vehicle reaction control, planetary retro, and planetary descent/ascent. This paper discusses on-board chemical propulsion technology, including bipropellants, monopropellants, and micropropulsion. Bipropellant propulsion has focused on maximizing the performance of Earth storable propellants by using high-temperature, oxidation-resistant chamber materials. The performance of bipropellant systems can be increased further, by operating at elevated chamber pressures and/or using higher energy oxidizers. Both options present system level difficulties for spacecraft, however. Monopropellant research has focused on mixtures composed of an aqueous solution of hydroxl ammonium nitrate (HAN) and a fuel component. HAN-based monopropellants, unlike hydrazine, do not present a vapor hazard and do not require extraordinary procedures for storage, handling, and disposal. HAN-based monopropellants generically have higher densities and lower freezing points than the state-of-art hydrazine and can higher performance, depending on the formulation. High-performance HAN-based monopropellants, however, have aggressive, high-temperature combustion environments and require advances in catalyst materials or suitable non-catalytic ignition options. The objective of the micropropulsion technology area is to develop low-cost, high-utility propulsion systems for the range of miniature spacecraft and precision propulsion applications.

Synthesis and evaluation of di- and trimeric hydroxylamine-based β-(1→3)-glucan mimetics.

PubMed

Ferry, Angélique; Malik, Gaëlle; Guinchard, Xavier; Vĕtvička, Václav; Crich, David

2014-10-22

Di- and trimeric hydroxylamine-based mimetics of β-(1→3)-glucans have been accessed by an asymmetric synthesis route featuring an iterative double ring-closing reductive amination reaction. These oligomeric hydroxylamines are demonstrated to inhibit the staining of human neutrophils and of mouse macrophages by fluorescent anti-CR3 and anti-dectin-1 antibodies, respectively, and to stimulate phagocytosis, all in a linkage-dependent manner suggestive of binding to the lectin domains of complement receptor 3 (CR3) and dectin-1. The ability of these relatively short mimetics to bind to CR3 and dectin-1, as compared to the greater degree of polymerization required in β-(1→3)-glucans, is discussed in terms of the increased hydrophobicity of the α-face on replacement of the glycosidic bond by the hydroxylamine linkage.

Thermal decomposition of hydroxylamine: isoperibolic calorimetric measurements at different conditions.

PubMed

Adamopoulou, Theodora; Papadaki, Maria I; Kounalakis, Manolis; Vazquez-Carreto, Victor; Pineda-Solano, Alba; Wang, Qingsheng; Mannan, M Sam

2013-06-15

Thermal decomposition of hydroxylamine, NH2OH, was responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting its decomposition are not being understood. In this work, the global enthalpy of hydroxylamine decomposition has been measured in the temperature range of 130-150 °C employing isoperibolic calorimetry. Measurements were performed in a metal reactor, employing 30-80 ml solutions containing 1.4-20 g of pure hydroxylamine (2.8-40 g of the supplied reagent). The measurements showed that increased concentration or temperature, results in higher global enthalpies of reaction per unit mass of reactant. At 150 °C, specific enthalpies as high as 8 kJ per gram of hydroxylamine were measured, although in general they were in the range of 3-5 kJ g(-1). The accurate measurement of the generated heat was proven to be a cumbersome task as (a) it is difficult to identify the end of decomposition, which after a fast initial stage, proceeds very slowly, especially at lower temperatures and (b) the environment of gases affects the reaction rate. Copyright © 2013 Elsevier B.V. All rights reserved.

Ceruloplasmin (ferroxidase) oxidizes hydroxylamine probes: deceptive implications for free radical detection

PubMed Central

Ganini, Douglas; Canistro, Donatella; Jang, JinJie; Stadler, Krisztian; Mason, Ronald P.; Kadiiska, Maria B.

2012-01-01

Ceruloplasmin (ferroxidase) is a copper-binding protein known to promote Fe2+ oxidation in plasma of mammals. Besides its classical ferroxidase activity, ceruloplasmin is known to catalyze the oxidation of various substrates, such as amines and catechols. Assays based on cyclic hydroxylamine oxidation are used to quantify and detect free radicals in biological samples ex vivo and in vitro. We show here that human ceruloplasmin promotes the oxidation of the cyclic hydroxylamine 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine hydrochloride (CPH) and related probes in Chelex-treated phosphate buffer and rat serum. The reaction is suppressed by the metal chelators DTPA, EDTA and Desferal, while heparin and bathocuproine have no effect. Catalase or SOD additions do not interfere with the CPH-oxidation yield, demonstrating that free radicals are not involved in the CPH oxidation mediated by ceruloplasmin. Plasma samples immunodepleted of ceruloplasmin have lower levels of CPH oxidation, which confirms the role of ceruloplasmin (ferroxidase) as a biological oxidizing agent of cyclic hydroxylamines. In conclusion, we show that the ferroxidase activity of ceruloplasmin is a possible biological source of artifacts in the cyclic hydroxylamine-oxidation assay used for ROS detection and quantification. PMID:22824865

Chemoselective amide formation using O-(4-nitrophenyl)hydroxylamines and pyruvic acid derivatives.

PubMed

Kumar, Sonali; Sharma, Rashi; Garcia, Megan; Kamel, Joseph; McCarthy, Caroline; Muth, Aaron; Phanstiel, Otto

2012-12-07

A series of O-(4-nitrophenyl)hydroxylamines were synthesized from their respective oximes using a pulsed addition of excess NaBH(3)CN at pH 3 in 65-75% yield. Steric hindrance near the oxime functional group played a key role in both the ease by which the oxime could be reduced and the subsequent reactivity of the respective hydroxylamine. Reaction of the respective hydroxylamines with pyruvic acid derivatives generated the desired amides in good yields. A comparison of phenethylamine systems bearing different leaving groups revealed significant differences in the rates of these systems and suggested that the leaving group ability of the N-OR substituent plays an important role in determining their reactivity with pyruvic acid. Competition experiments (in 68% DMSO/phosphate buffered saline) using 1 equiv of N-phenethyl-O-(4-nitrophenyl)hydroxylamine and 2 equiv of pyruvic acid in the presence of other nucleophiles such as glycine, cysteine, phenol, hexanoic acid, and lysine demonstrated that significant chemoselectivity is present in this reaction. The results suggest that this chemoselective reaction can occur in the presence of excess α-amino acids, phenols, acids, thiols, and amines.

Intermolecular cope-type hydroamination of alkenes and alkynes using hydroxylamines.

PubMed

Moran, Joseph; Gorelsky, Serge I; Dimitrijevic, Elena; Lebrun, Marie-Eve; Bédard, Anne-Catherine; Séguin, Catherine; Beauchemin, André M

2008-12-31

The development of the Cope-type hydroamination as a method for the metal- and acid-free intermolecular hydroamination of hydroxylamines with alkenes and alkynes is described. Aqueous hydroxylamine reacts efficiently with alkynes in a Markovnikov fashion to give oximes and with strained alkenes to give N-alkylhydroxylamines, while unstrained alkenes are more challenging. N-Alkylhydroxylamines also display similar reactivity with strained alkenes and give modest to good yields with vinylarenes. Electron-rich vinylarenes lead to branched products while electron-deficient vinylarenes give linear products. A beneficial additive effect is observed with sodium cyanoborohydride, the extent of which is dependent on the structure of the hydroxylamine. The reaction conditions are found to be compatible with common protecting groups, free OH and NH bonds, as well as bromoarenes. Both experimental and theoretical results suggest the proton transfer step of the N-oxide intermediate is of vital importance in the intermolecular reactions of alkenes. Details are disclosed concerning optimization, reaction scope, limitations, and theoretical analysis by DFT, which includes a detailed molecular orbital description for the concerted hydroamination process and an exhaustive set of calculated potential energy surfaces for the reactions of various alkenes, alkynes, and hydroxylamines.

Iron(II)-catalyzed intermolecular amino-oxygenation of olefins through the N-O bond cleavage of functionalized hydroxylamines.

PubMed

Lu, Deng-Fu; Zhu, Cheng-Liang; Jia, Zhen-Xin; Xu, Hao

2014-09-24

An iron-catalyzed diastereoselective intermolecular olefin amino-oxygenation reaction is reported, which proceeds via an iron-nitrenoid generated by the N-O bond cleavage of a functionalized hydroxylamine. In this reaction, a bench-stable hydroxylamine derivative is used as the amination reagent and oxidant. This method tolerates a range of synthetically valuable substrates that have been all incompatible with existing amino-oxygenation methods. It can also provide amino alcohol derivatives with regio- and stereochemical arrays complementary to known amino-oxygenation methods.

Preparation of 3,5-disubstituted pyrazoles and isoxazoles from terminal alkynes, aldehydes, hydrazines, and hydroxylamine.

PubMed

Harigae, Ryo; Moriyama, Katsuhiko; Togo, Hideo

2014-03-07

The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstituted isoxazoles from terminal alkynes, aldehydes, molecular iodine, and hydroxylamine.

Ceruloplasmin (ferroxidase) oxidizes hydroxylamine probes: deceptive implications for free radical detection.

PubMed

Ganini, Douglas; Canistro, Donatella; Jiang, JinJie; Jang, JinJie; Stadler, Krisztian; Mason, Ronald P; Kadiiska, Maria B

2012-10-01

Ceruloplasmin (ferroxidase) is a copper-binding protein known to promote Fe(2+) oxidation in plasma of mammals. In addition to its classical ferroxidase activity, ceruloplasmin is known to catalyze the oxidation of various substrates, such as amines and catechols. Assays based on cyclic hydroxylamine oxidation are used to quantify and detect free radicals in biological samples ex vivo and in vitro. We show here that human ceruloplasmin promotes the oxidation of the cyclic hydroxylamine 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine hydrochloride (CPH) and related probes in Chelex-treated phosphate buffer and rat serum. The reaction is suppressed by the metal chelators DTPA, EDTA, and desferal, whereas heparin and bathocuproine have no effect. Catalase or superoxide dismutase additions do not interfere with the CPH-oxidation yield, demonstrating that oxygen-derived free radicals are not involved in the CPH oxidation mediated by ceruloplasmin. Plasma samples immunodepleted of ceruloplasmin have lower levels of CPH oxidation, which confirms the role of ceruloplasmin (ferroxidase) as a biological oxidizing agent of cyclic hydroxylamines. In conclusion, we show that the ferroxidase activity of ceruloplasmin is a possible biological source of artifacts in the cyclic hydroxylamine-oxidation assay used for reactive oxygen species detection and quantification. Published by Elsevier Inc.

Hydrazine and hydroxylamine as probes for O2-reduction site of mitochondrial cytochrome c oxidase.

PubMed Central

Kubota, T; Yoshikawa, S

1993-01-01

Reactions of hydrazine and hydroxylamine with bovine heart cytochrome c oxidase in the fully reduced state were investigated under anaerobic conditions following the visible-Soret spectral change. Hydrazine gave a sharp band at 575 nm with 20% decrease in the alpha band at 603 nm, and hydroxylamine induced a 2 nm blue-shift for the alpha band without any clear splitting. The Soret band at 443 nm was decreased significantly in intensity, with the concomitant appearance of a shoulder with hydrazine or a peak with hydroxylamine, both near 430 nm. The dependence on pH of the affinity of these reagents for the enzyme indicates that only the deprotonated forms of these reagents bind to the enzyme, suggesting a highly hydrophobic environment of the haem ligand-biding site. These spectral changes were largely removed by addition of cyanide or CO. However, detailed analysis of these spectral changes indicates that hydrazine perturbs the shape of the spectral change induced by cyanide and hydroxylamine perturbs that induced by CO. These results suggest that these aldehyde reagents bind to haem a3 iron as well as to a second site which is most likely to be the formyl group on the haem periphery, and that these two sites bind these reagents anti-cooperatively with each other. PMID:8389138

Cell surface acid-base properties of Escherichia coli and Bacillus brevis and variation as a function of growth phase, nitrogen source and C:N ratio.

PubMed

Hong, Yongsuk; Brown, Derick G

2006-07-01

Potentiometric titration has been conducted to systematically examine the acid-base properties of the cell surfaces of Escherichia coli K-12 and Bacillus brevis as a function of growth phase, nitrogen source (ammonium or nitrate), and carbon to nitrogen (C:N) ratio of the growth substrate. The two bacterial species revealed four distinct proton binding sites, with pK(a) values in the range of 3.08-4.05 (pK(1)), 4.62-5.57 (pK(2)), 6.47-7.30 (pK(3)), and 9.68-10.89 (pK(4)) corresponding to phosphoric/carboxylic, carboxylic, phosphoric, and hydroxyl/amine groups, respectively. Two general observations in the data are that for B. brevis the first site concentration (N(1)), corresponding to phosphoric/carboxylic groups (pK(1)), varied as a function of nitrogen source, while for E. coli the fourth site concentration (N(4)), corresponding to hydroxyl/amine groups (pK(4)), varied as a function of C:N ratio. Correspondingly, it was found that N(1) was the highest of the four site concentrations for B. brevis and N(4) was the highest for E. coli. The concentrations of the remaining sites showed little variation. Finally, comparison between the titration data and a number of cell surface compositional studies in the literature indicates one distinct difference between the two bacteria is that pK(4) of the Gram-negative E. coli can be attributed to hydroxyl groups while that of the Gram-positive B. brevis can be attributed to amine groups.

The contribution of hydroxylamine content to spatial variability of N2O formation in soil of a Norway spruce forest

NASA Astrophysics Data System (ADS)

Liu, Shurong; Herbst, Michael; Bol, Roland; Gottselig, Nina; Pütz, Thomas; Weymann, Daniel; Wiekenkamp, Inge; Vereecken, Harry; Brüggemann, Nicolas

2016-04-01

Hydroxylamine (NH2OH), a reactive intermediate of several microbial nitrogen turnover processes, is a potential precursor of nitrous oxide (N2O) formation in the soil. However, the contribution of soil NH2OH to soil N2O emission rates in natural ecosystems is unclear. Here, we determined the spatial variability of NH2OH content and potential N2O emission rates of organic (Oh) and mineral (Ah) soil layers of a Norway spruce forest, using a recently developed analytical method for the determination of soil NH2OH content, combined with a geostatistical Kriging approach. Potential soil N2O emission rates were determined by laboratory incubations under oxic conditions, followed by gas chromatographic analysis and complemented by ancillary measurements of soil characteristics. Stepwise multiple regressions demonstrated that the potential N2O emission rates, NH2OH and nitrate (NO3-) content were spatially highly correlated, with hotspots for all three parameters observed in the headwater of a small creek flowing through the sampling area. In contrast, soil ammonium (NH4+) was only weakly correlated with potential N2O emission rates, and was excluded from the multiple regression models. While soil NH2OH content explained the potential soil N2O emission rates best for both layers, also NO3- and Mn content turned out to be significant parameters explaining N2O formation in both soil layers. The Kriging approach was improved markedly by the addition of the co-variable information of soil NH2OH and NO3- content. The results indicate that determination of soil NH2OH content could provide crucial information for the prediction of the spatial variability of soil N2O emissions.

Probing the reactivation process of sarin-inhibited acetylcholinesterase with α-nucleophiles: hydroxylamine anion is predicted to be a better antidote with DFT calculations.

PubMed

Khan, Md Abdul Shafeeuulla; Lo, Rabindranath; Bandyopadhyay, Tusar; Ganguly, Bishwajit

2011-08-01

Inactivation of acetylcholinesterase (AChE) due to inhibition by organophosphorus (OP) compounds is a major threat to human since AChE is a key enzyme in neurotransmission process. Oximes are used as potential reactivators of OP-inhibited AChE due to their α-effect nucleophilic reactivity. In search of more effective reactivating agents, model studies have shown that α-effect is not so important for dephosphylation reactions. We report the importance of α-effect of nucleophilic reactivity towards the reactivation of OP-inhibited AChE with hydroxylamine anion. We have demonstrated with DFT [B3LYP/6-311G(d,p)] calculations that the reactivation process of sarin-serine adduct 2 with hydroxylamine anion is more efficient than the other nucleophiles reported. The superiority of hydroxylamine anion to reactivate the sarin-inhibited AChE with sarin-serine adducts 3 and 4 compared to formoximate anion was observed in the presence and absence of hydrogen bonding interactions of Gly121 and Gly122. The calculated results show that the rates of reactivation process of adduct 4 with hydroxylamine anion are 261 and 223 times faster than the formoximate anion in the absence and presence of such hydrogen bonding interactions. The DFT calculated results shed light on the importance of the adjacent carbonyl group of Glu202 for the reactivation of sarin-serine adduct, in particular with formoximate anion. The reverse reactivation reaction between hydroxylamine anion and sarin-serine adduct was found to be higher in energy compared to the other nucleophiles, which suggests that this α-nucleophile can be a good antidote agent for the reactivation process. Copyright © 2011 Elsevier Inc. All rights reserved.

Amperometric Detection of Sub-ppm Formaldehyde Using Single-Walled Carbon Nanotubes and Hydroxylamines: A Referenced Chemiresistive System.

PubMed

Ishihara, Shinsuke; Labuta, Jan; Nakanishi, Takashi; Tanaka, Takeshi; Kataura, Hiromichi

2017-10-27

We report amperometric detection of formaldehyde (HCHO) using hydroxylamine hydrochloride and single-walled carbon nanotubes (SWCNTs). Hydroxylamine hydrochloride reacts with HCHO to emit HCl vapor, which injects a hole carrier into semiconducting SWCNTs. The increase of conductivity in SWCNTs is easily monitored using an ohmmeter. The debundling of SWCNTs with a metallo-supramolecular polymer (MSP) increased the active surface area in the SWCNTs network, leading to excellent sensitivity to HCHO with a limit of detection (LoD) of 0.016 ppm. The response of sensor is reversible, and the sensor is reusable. The selectivity to HCHO is 10 5 -10 6 times higher than interferences with other volatiles such as water, methanol, and toluene. Moreover, false-positive responses caused by a significant variation of humidity and/or temperature are successfully discriminated from true-positive responses by using two sensors, one with and the other without hydroxylamine hydrochloride, in a referenced system.

Improved synthesis of (S)-N-Boc-5-oxaproline for protein synthesis with the α-ketoacid-hydroxylamine (KAHA) ligation.

PubMed

Murar, Claudia E; Harmand, Thibault J; Bode, Jeffrey W

2017-09-15

We describe a new route for the synthesis of (S)-N-Boc-5-oxaproline. This building block is a key element for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA) ligation. The new synthetic pathway to the enantiopure oxaproline is based on a chiral amine mediated enantioselective conjugate addition of a hydroxylamine to trans-4-oxo-2-butenoate. This route is practical, scalable and economical and provides decagram amounts of material for protein synthesis and conversion to other protected forms of (S)-oxaproline. Copyright © 2017 Elsevier Ltd. All rights reserved.

Volumetric, rheological, and optical properties of hydroxylamine hydrochloride aqueous solutions containing NaCl, KCl, and NH4Cl at 30°C

NASA Astrophysics Data System (ADS)

Deosarkar, S. D.; Puyad, A. L.; Shaikh, U. B.; Solanke, S. S.

2014-04-01

Densities, viscosities, and refractive indices of aqueous solutions of hydroxylamine hydrochloride containing 0.05, 0.10, and 0.15 mol/dm3 NaCl, KCl, and NH4Cl were measured at different concentrations of hydroxylamine hydrochloride at 30°C. Viscosity coefficients A and B representing ion-ion and ion-solvent interactions were determined from Jones-Dole equation. Experimental properties and viscosity coefficients have been interpreted in terms of ion-ion and ion-solvent interactions. Ion-solvent interactions were found to be dominating over the ion-ion interactions in studied systems.

Selective inhibition of ammonium oxidation and nitrification-linked N2O formation by methyl fluoride and dimethyl ether

USGS Publications Warehouse

Miller, L.G.; Coutlakis, M.D.; Oremland, R.S.; Ward, B.B.

1993-01-01

Methyl fluoride (CH3F) and dimethyl ether (DME) inhibited nitrification in washed-cell suspensions of Nitrosomonas europaea and in a variety of oxygenated soils and sediments. Headspace additions of CH3F (10% [vol/vol]) and DME (25% [vol/vol]) fully inhibited NO2- and N2O production from NH4+ in incubations of N. europaea, while lower concentrations of these gases resulted in partial inhibition. Oxidation of hydroxylamine (NH2OH) by N. europaea and oxidation of NO2- by a Nitrobacter sp. were unaffected by CH3F or DME. In nitrifying soils, CH3F and DME inhibited N2O production. In field experiments with surface flux chambers and intact cores, CH3F reduced the release of N2O from soils to the atmosphere by 20- to 30-fold. Inhibition by CH3F also resulted in decreased NO3- + NO2- levels and increased NH4+ levels in soils. CH3F did not affect patterns of dissimilatory nitrate reduction to ammonia in cell suspensions of a nitrate- respiring bacterium, nor did it affect N2O metabolism in denitrifying soils. CH3F and DME will be useful in discriminating N2O production via nitrification and denitrification when both processes occur and in decoupling these processes by blocking NO2- and NO3- production.

Simultaneous Heterotrophic Nitrification and Aerobic Denitrification by Chryseobacterium sp. R31 Isolated from Abattoir Wastewater

PubMed Central

Kundu, Pradyut; Pramanik, Arnab; Dasgupta, Arpita; Mukherjee, Somnath; Mukherjee, Joydeep

2014-01-01

A heterotrophic carbon utilizing microbe (R31) capable of simultaneous nitrification and denitrification (SND) was isolated from wastewater of an Indian slaughterhouse. From an initial COD value of 583.0 mg/L, 95.54% was removed whilst, from a starting NH4 +-N concentration of 55.7 mg/L, 95.87% was removed after 48 h contact. The concentrations of the intermediates hydroxylamine, nitrite, and nitrate were low, thus ensuring nitrogen removal. Aerobic denitrification occurring during ammonium removal by R31 was confirmed by utilization of both nitrate and nitrite as nitrogen substrates. Glucose and succinate were superior while acetate and citrate were poor substrates for nitrogen removal. Molecular phylogenetic identification, supported by chemotaxonomic and physiological properties, assigned R31 as a close relative of Chryseobacterium haifense. The NH4 +-N utilization rate and growth of strain R31 were found to be higher at C/N = 10 in comparison to those achieved with C/N ratios of 5 and 20. Monod kinetic coefficients, half saturation concentration (K s), maximum rate of substrate utilization (k), yield coefficient, (Y) and endogenous decay coefficient (K d) indicated potential application of R31 in large-scale SND process. This is the first report on concomitant carbon oxidation, nitrification, and denitrification in the genus Chryseobacterium and the associated kinetic coefficients. PMID:24991552

Reverse cope elimination of hydroxylamines and alkenes or alkynes: theoretical investigation of tether length and substituent effects.

PubMed

Krenske, Elizabeth H; Davison, Edwin C; Forbes, Ian T; Warner, Jacqueline A; Smith, Adrian L; Holmes, Andrew B; Houk, K N

2012-02-01

Quantum mechanical calculations have been used to study the intramolecular additions of hydroxylamines to alkenes and alkynes ("reverse Cope eliminations"). In intermolecular reverse Cope eliminations, alkynes are more reactive than alkenes. However, competition experiments have shown that tethering the hydroxylamine to the alkene or alkyne can reverse the reactivity order from that normally observed. The exact outcome depends on the length of the tether. In agreement with experiment, a range of density functional theory methods and CBS-QB3 calculations predict that the activation energies for intramolecular reverse Cope eliminations follow the order 6-exo-dig < 5-exo-trig < 5-exo-dig ≈ 7-exo-dig. The order of the barriers for the 5-, 6-, and 7-exo-dig reactions of alkynes arises mainly from differences in tether strain in the transition states (TSs), but is also influenced by the TS interaction between the hydroxylamine and alkyne. Cyclization onto an alkene in the 5-exo-trig fashion incurs slightly less tether strain than a 6-exo-dig alkyne cyclization, but its activation energy is higher because the hydroxylamine fragment must distort more before the TS is reached. If the alkene terminus is substituted with two methyl groups, the barrier becomes so much higher that it is also disfavored compared to the 5- and 7-exo-dig cyclizations. © 2012 American Chemical Society

Hydroxylamine diffusion can enhance N₂O emissions in nitrifying biofilms: a modeling study.

PubMed

Sabba, Fabrizio; Picioreanu, Cristian; Pérez, Julio; Nerenberg, Robert

2015-02-03

Wastewater treatment plants can be significant sources of nitrous oxide (N2O), a potent greenhouse gas. However, little is known about N2O emissions from biofilm processes. We adapted an existing suspended-growth mathematical model to explore N2O emissions from nitrifying biofilms. The model included N2O formation by ammonia-oxidizing bacteria (AOB) via the hydroxylamine and the nitrifier denitrification pathways. Our model suggested that N2O emissions from nitrifying biofilms could be significantly greater than from suspended growth systems under similar conditions. The main cause was the formation and diffusion of hydroxylamine, an AOB nitrification intermediate, from the aerobic to the anoxic regions of the biofilm. In the anoxic regions, hydroxylamine oxidation by AOB provided reducing equivalents used solely for nitrite reduction to N2O, since there was no competition with oxygen. For a continuous system, very high and very low dissolved oxygen (DO) concentrations resulted in lower emissions, while intermediate values led to higher emissions. Higher bulk ammonia concentrations and greater biofilm thicknesses increased emissions. The model effectively predicted N2O emissions from an actual pilot-scale granular sludge reactor for sidestream nitritation, but significantly underestimated the emissions when the NH2OH diffusion coefficient was assumed to be minimal. This numerical study suggests an unexpected and important role of hydroxylamine in N2O emission in biofilms.

The Reverse Cope Elimination of Hydroxylamines and Alkenes or Alkynes: Theoretical Investigation of Tether Length and Substituent Effects

PubMed Central

Krenske, Elizabeth H.; Davison, Edwin C.; Forbes, Ian T.; Warner, Jacqueline A.; Smith, Adrian L.; Holmes, Andrew B.; Houk, K. N.

2012-01-01

Quantum mechanical calculations have been used to study the intramolecular additions of hydroxylamines to alkenes and alkynes (“reverse Cope eliminations”). In intermolecular reverse Cope eliminations, alkynes are more reactive than alkenes. However, competition experiments have shown that tethering the hydroxylamine to the alkene or alkyne can reverse the reactivity order from that normally observed. The exact outcome depends on the length of the tether. In agreement with experiment, a range of density functional theory methods and CBS-QB3 calculations predict that the activation energies for intramolecular reverse Cope eliminations follow the order 6-exo-dig < 5-exo-trig < 5-exo-dig ≈ 7-exo-dig. The order of the barriers for the 5-, 6-, and 7-exo-dig reactions of alkynes arises mainly from differences in tether strain in the transition states, but is also influenced by the transition-state interaction between the hydroxylamine and alkyne. Cyclization onto an alkene in the 5-exo-trig fashion incurs slightly less tether strain than a 6-exo-dig alkyne cyclization, but its activation energy is higher because the hydroxylamine fragment must distort more before the TS is reached. If the alkene terminus is substituted with two methyl groups, the barrier becomes so much higher that it is also disfavored compared to the 5- and 7-exo-dig cyclizations. PMID:22280245

Development of a novel hydroxyl ammonium nitrate based liquid propellant for air-independent propulsion

NASA Astrophysics Data System (ADS)

Fontaine, Joseph Henry

The focus of this dissertation is the development of an Unmanned Undersea Vehicle (UUV) liquid propellant employing Hydroxyl Ammonium Nitrate (HAN) as the oxidizer. Hydroxyl Ammonium Nitrate is a highly acidic aqueous based liquid oxidizer. Therefore, in order to achieve efficient combustion of a propellant using this oxidizer, the fuel must be highly water soluble and compatible with the oxidizer to prevent a premature ignition prior to being heated within the combustion chamber. An extensive search of the fuel to be used with this oxidizer was conducted. Propylene glycol was chosen as the fuel for this propellant, and the propellant given the name RF-402. The propellant development process will first evaluate the propellants thermal stability and kinetic parameters using a Differential Scanning Calorimeter (DSC). The purpose of the thermal stability analysis is to determine the temperature at which the propellant decomposition begins for the future safe handling of the propellant and the optimization of the combustion chamber. Additionally, the thermogram results will provide information regarding any undesirable endotherms prior to the decomposition and whether or not the decomposition process is a multi-step process. The Arrhenius type kinetic parameters will be determined using the ASTM method for thermally unstable materials. The activation energy and pre-exponential factor of the propellant will be determined by evaluating the decomposition peak temperature over a temperature scan rate ranging from 1°C per minute to 10°C per minute. The kinetic parameters of the propellant will be compared to those of 81 wt% HAN to determine if the HAN decomposition is controlling the overall decomposition of the propellant RF-402. The lifetime of individual droplets will be analyzed using both experimental and theoretical techniques. The theoretical technique will involve modeling the lifetime of an individual droplet in a combustion chamber like operating environment. The experimental technique will consist of subjecting droplets suspended from a fine gauge thermocouple to an instantaneous hot gas source and recording its temperature response while imaging it using a high power video microscope to determine the physical response of the droplet. This analysis will be the foundation for all future efforts in developing a propulsion system employing the use of RF-402.

Copper(II)-catalyzed electrophilic amination of quinoline N-oxides with O-benzoyl hydroxylamines.

PubMed

Li, Gang; Jia, Chunqi; Sun, Kai; Lv, Yunhe; Zhao, Feng; Zhou, Kexiao; Wu, Hankui

2015-03-21

Copper acetate-catalyzed C-H bond functionalization amination of quinoline N-oxides was achieved using O-benzoyl hydroxylamine as an electrophilic amination reagent, thereby affording the desired products in moderate to excellent yields. Electrophilic amination can also be performed in good yield on a gram scale.

Pathways for Intracellular Generation of Oxidants and Tyrosine Nitration by a Macrophage Cell Line†

PubMed Central

Palazzolo-Ballance, Amy M.; Suquet, Christine; Hurst, James K.

2008-01-01

Two transformed murine macrophage cell lines (RAW 264.7 ATCC TIB-71 and CRL-2278) were examined for oxidant production at various times following activation by using a set of fluorescence and ESR-active probes. Stimulation with a soluble agonist or activation with bacterial lipopolysaccharide plus γ-interferon caused only very small initial increases in O2 consumption above basal rates; however, at 2-4 h post-activation, respiration increased to 2-3 fold and remained at these elevated levels over the subsequent lifetime of the cell (20-30 h). Oxidation reactions were confined primarily within the cell, as was demonstrated by using phagocytosable dichlorodihydrofluorescein-conjugated latex beads and cyclic hydroxylamines with differing membrane permeabilities. From the intrinsic reactivities of these probes and the time course of their oxidations, one infers induction of apparent peroxidase activity beginning at ∼2 h post-activation, coinciding with the increase in overall respiratory rate; this acquired capability was accompanied by accumulation of a stable horseradish peroxidase-reactive oxidant, presumably H2O2, in the extracellular medium,. Nitrite ion rapidly accumulated in the extracellular medium over a period of 5-8 h post-activation in both cell lines, indicating the presence of active nitric oxide synthase (iNOS) during that period. Prostaglandin endoperoxide H synthase (COX-2) activity was detected at 15-20 h post-activation by use of sensitive peroxide assay in conjunction with a COX-2 specific inhibitor (DuP-697). Superoxide formation was detected by reaction with hydroethidine within the first hour following activation, but not thereafter. Consistent with the absence of significant respiratory stimulation, the amount of O2·- formed was very small; comparative reactions of cyclic hydroxylamine probes indicated that virtually none of the O2·- was discharged into the external medium. Myeloperoxidase (MPO) activity was probed at various times post-activation by using fluorescein-conjugated polyacrylamide beads, which efficiently trap MPO-generated HOCl in neutrophils to give stable chlorofluorescein products. However, chlorination of the dye was not detected under any conditions in RAW cells, virtually precluding MPO involvement in their intracellular reactions. This same probe was used to determine changes in intraphagosomal pH, which increased slowly from ∼6.5 to ∼8.2 over a 20 h post-phagocytosis period. The cumulative data suggest activation is followed by sequential induction of an endogenous peroxidase, iNOS, and COX-2, with NADPH oxidase-derived O2·- playing a minimal role in direct generation of intracellular oxidants. To account for reported observations of intracellular tyrosine nitration late in the life cycles of macrophages, we propose a novel mechanism wherein iNOS-generated NO2- is used by COX-2 to produce NO2· as a terminal microbicidal oxidant and nitrating agent. PMID:17530864

PRECIPITATION OF PLUTONOUS PEROXIDE

DOEpatents

Barrick, J.G.; Manion, J.P.

1961-08-15

A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

Dissociative adsorption of a multifunctional compound on a semiconductor surface: a theoretical study of the adsorption of hydroxylamine on Ge(100).

PubMed

Park, Hyunkyung; Kim, Do Hwan

2018-06-06

The adsorption behavior of hydroxylamine on a Ge(100) surface was investigated using density functional theory (DFT) calculations. These calculations predicted that hydroxylamine, a multifunctional compound consisting of a hydroxyl group and an amine group, would initially become adsorbed through N-dative bonding, or alternatively through the hydroxyl group via O-H dissociative adsorption. An N-O dissociative reaction may also occur, mainly via N-dative molecular adsorption, and the N-O dissociative product was calculated to be the most stable of all the possible adsorption structures. The calculations furthermore indicated the formation of the N-O dissociative product from the N-dative structure to be nearly barrierless and the dissociated hydroxyl and amine groups to be bonded to two Ge atoms of adjacent Ge dimers. Simulated STM images suggested the change in electron density that would occur upon adsorption of hydroxylamine in various adsorption configurations, and specifically indicated the N-O dissociative product to have greater electron density around the amine groups, and the hydroxyl groups to mainly contribute electron density to the unoccupied electronic states.

Suicide inactivation of hydroxylamine oxidoreductase of Nitrosomonas europaea by organohydrazines.

PubMed

Logan, M S; Hooper, A B

1995-07-18

In the presence of a suitable electron acceptor such as mammalian cytochrome c, hydroxylamine oxidoreductase (HAO) from the chemolithotrophic bacterium Nitrosomonas europaea catalyzes the oxidation of hydroxylamine or hydrazine to nitrite or dinitrogen, respectively. Each subunit of HAO contains 7 c-hemes and a chromophore of the active site called heme P460, a c-heme bridged from a methylene carbon to a ring carbon of a tyrosine of the peptide chain. Reaction with either substrate results in reduction of several c-hemes of HAO. The reaction of organohydrazines with HAO was investigated in this work. HAO was inactivated by (phenyl-, (methyl-, or (hydroxyethyl)hydrazine. The process followed first order kinetics and was inhibited by the substrates, hydroxylamine or hydrazine. Complete loss of enzyme activity and absorbancy characteristic of native heme P460 of HAO occurred at a 1:1 ratio of phenylhydrazine and HAO. HAO was covalently derivatized by two molecules of [14C]-phenylhydrazine per subunit. Heme P460 was derivatized with high affinity, and an amino acid residue was derivatized with lower affinity. c-Hemes were not derivatized except for the partial reaction of (hydroxyethyl)hydrazine with one heme. As with hydroxylamine and hydrazine, incubation with organohydrazines resulted in reduction of c-heme of HAO. Derivatized minus native optical difference spectra of ferric or ferrous HAO revealed changes in the optical properties of heme P460 which were generally similar to shifts seen in the reaction of the heme of other hemoproteins with organohydrazines.(ABSTRACT TRUNCATED AT 250 WORDS)

Familiarization and Detection of Green Monopropellants Image

NASA Technical Reports Server (NTRS)

Coan, Mary R.

2015-01-01

Ammonium dinitramide (ADN) and hydroxyl ammonium nitrate (HAN) are green monopropellants which will be appearing at Kennedy Space Center (KSC) for processing in the next few years. These are relatively safe replacements for hydrazine as a monopropellant; however, little is known about methods of leak detection, vapor scrubbing, air emissions, or cleanup that will be required for safe and environmentally benign operations at KSC. The goal of this work is to develop leak detection and related technologies for the two new green monopropellants.

Familiarization and Detection of Green Monopropellants Project

NASA Technical Reports Server (NTRS)

Coan, Mary Rachel (Compiler)

2014-01-01

Ammonium dinitramide (ADN) and hydroxyl ammonium nitrate (HAN) are green monopropellants which will be appearing at Kennedy Space Center (KSC) for processing in the next few years. These are relatively safe replacements for hydrazine as a monopropellant; however, little is known about methods of leak detection, vapor scrubbing, air emissions, or cleanup that will be required for safe and environmentally benign operations at KSC. The goal of this work is to develop leak detection and related technologies for the two new green monopropellants.

Hydroxylammonium Nitrate Compatibility Tests with Various Materials - A Liquid Propellant Study

DTIC Science & Technology

1990-07-01

evolved gas was determined by gas analysis. The propellant off-loaded from the test tube was analyzed for leached metals (if the material was a...HAN Solution 15 - The amount of gas evolved during the 30-day observation period was calculated from the ullage volume of the flask, the pressure read...much volume and was ignored. The length of the U-gauge was 34 cm from top to bottom of the U. The full scale range was 300 mm Hg corresponding to a gas

Hydroxylamine-O-sulfonamide is a versatile lead compound for the development of carbonic anhydrase inhibitors.

PubMed

Di Fiore, Anna; Vergara, Alessandro; Caterino, Marco; Alterio, Vincenzo; Monti, Simona M; Ombouma, Joanna; Dumy, Pascal; Vullo, Daniela; Supuran, Claudiu T; Winum, Jean-Yves; De Simone, Giuseppina

2015-07-21

Hydroxylamine-O-sulfonamide, a molecule incorporating two zinc-binding groups (ZBGs), has been investigated as a carbonic anhydrase inhibitor (CAI) by means of kinetic, crystallographic and Raman spectroscopy studies, highlighting interesting results on its mechanism of action. These data can be exploited to design new, effective and selective CAIs.

Transition Metal Free C-N Bond Forming Dearomatizations and Aryl C-H Aminations by in Situ Release of a Hydroxylamine-Based Aminating Agent.

PubMed

Farndon, Joshua J; Ma, Xiaofeng; Bower, John F

2017-10-11

We outline a simple protocol that accesses directly unprotected secondary amines by intramolecular C-N bond forming dearomatization or aryl C-H amination. The method is dependent on the generation of a potent electrophilic aminating agent released by in situ deprotection of O-Ts activated N-Boc hydroxylamines.

Synthesis of substituted pyrazines

DOEpatents

Pagoria, Philip F.; Zhang, Mao Xi

2016-10-04

A method for synthesizing a pyrazine-containing material according to one embodiment includes contacting an iminodiacetonitrile derivative with a base and a reagent selected from a group consisting of hydroxylamine, a hydroxylamine salt, an aliphatic primary amine, a secondary amine, an aryl-substituted alkylamine a heteroaryl-substituted alkyl amine, an alcohol, an alkanolamine and an aryl alcoholamine. Additional methods and several reaction products are presented. ##STR00001##

N-O chemistry for antibiotics: discovery of N-alkyl-N-(pyridin-2-yl)hydroxylamine scaffolds as selective antibacterial agents using nitroso Diels-Alder and ene chemistry.

PubMed

Wencewicz, Timothy A; Yang, Baiyuan; Rudloff, James R; Oliver, Allen G; Miller, Marvin J

2011-10-13

The discovery, syntheses, and structure-activity relationships (SAR) of a new family of heterocyclic antibacterial compounds based on N-alkyl-N-(pyridin-2-yl)hydroxylamine scaffolds are described. A structurally diverse library of ∼100 heterocyclic molecules generated from Lewis acid-mediated nucleophilic ring-opening reactions with nitroso Diels-Alder cycloadducts and nitroso ene reactions with substituted alkenes was evaluated in whole cell antibacterial assays. Compounds containing the N-alkyl-N-(pyridin-2-yl)hydroxylamine structure demonstrated selective and potent antibacterial activity against the Gram-positive bacterium Micrococcus luteus ATCC 10240 (MIC(90) = 2.0 μM or 0.41 μg/mL) and moderate activity against other Gram-positive strains including antibiotic resistant strains of Staphylococcus aureus (MRSA) and Enterococcus faecalis (VRE). A new synthetic route to the active core was developed using palladium-catalyzed Buchwald-Hartwig amination reactions of N-alkyl-O-(4-methoxybenzyl)hydroxylamines with 2-halo-pyridines that facilitated SAR studies and revealed the simplest active structural fragment. This work shows the value of using a combination of diversity-oriented synthesis (DOS) and parallel synthesis for identifying new antibacterial scaffolds.

Interactions of the H5 pore region and hydroxylamine with N-type inactivation in the Shaker K+ channel.

PubMed Central

Yool, A J; Schwarz, T L

1995-01-01

Mutations at sites in the H5 region of the Shaker B K+ channel were used to analyze the influence of the pore on N-type inactivation. Single-channel and two-electrode voltage clamp analyses showed that mutations at residues T441 and T442, which are thought to lie at the internal mouth of the pore, produced opposite effects on inactivation: the inactivated state is stabilized by T441S and destabilized by T442S. In addition, an ammonium derivative, hydroxylamine (OH-(NH3)+), appears to bind in the pore region of T441S and further decreases the rate of recovery from N-type inactivation. This effect relies on the presence of the amino-terminal. The effect of hydroxylamine on the T441S mutation of this K+ channel shows several properties analogous to those of local anesthetics on the Na+ channel. These results can be interpreted to suggest that part of the H5 region contributes to the receptor for the inactivation particle and that a hydroxylamine ion trapped near that site can stabilize their interaction. Images FIGURE 8 PMID:7696498

N-O Chemistry for Antibiotics: Discovery of N-Alkyl-N-(pyridin-2-yl)hydroxylamine Scaffolds as Selective Antibacterial Agents Using Nitroso Diels-Alder and Ene Chemistry

PubMed Central

Wencewicz, Timothy A.; Yang, Baiyuan; Rudloff, James R.; Oliver, Allen G.; Miller, Marvin J.

2011-01-01

The discovery, syntheses, and structure-activity relationships (SAR) of a new family of heterocyclic antibacterial compounds based on N-alkyl-N-(pyridin-2-yl)hydroxylamine scaffolds are described. A structurally diverse library of ~100 heterocyclic molecules generated from Lewis acid-mediated nucleophilic ring opening reactions with nitroso Diels-Alder cycloadducts and nitroso ene reactions with substituted alkenes was evaluated in whole cell antibacterial assays. Compounds containing the N-alkyl-N-(pyridin-2-yl)hydroxylamine structure demonstrated selective and potent antibacterial activity against the Gram-positive bacterium Micrococcus luteus ATCC 10240 (MIC90 = 2.0 μM or 0.41 μg/mL) and moderate activity against other Gram-positive strains including antibiotic resistant strains of Staphylococcus aureus (MRSA) and Enterococcus faecalis (VRE). A new synthetic route to the active core was developed using palladium-catalyzed Buchwald-Hartwig amination reactions of N-alkyl-O-(4-methoxybenzyl)hydroxylamines with 2-halo-pyridines that facilitated SAR studies and revealed the simplest active structural fragment. This work shows the value of using a combination of diversity-oriented synthesis (DOS) and parallel synthesis for identifying new antibacterial scaffolds. PMID:21859126

Formation of Hydroxylamine on Dust Grains via Ammonia Oxidation

NASA Astrophysics Data System (ADS)

He, Jiao; Vidali, Gianfranco; Lemaire, Jean-Louis; Garrod, Robin T.

2015-01-01

The quest to detect prebiotic molecules in space, notably amino acids, requires an understanding of the chemistry involving nitrogen atoms. Hydroxylamine (NH2OH) is considered a precursor to the amino acid glycine. Although not yet detected, NH2OH is considered a likely target of detection with ALMA. We report on an experimental investigation of the formation of hydroxylamine on an amorphous silicate surface via the oxidation of ammonia. The experimental data are then fed into a simulation of the formation of NH2OH in dense cloud conditions. On ices at 14 K and with a modest activation energy barrier, NH2OH is found to be formed with an abundance that never falls below a factor 10 with respect to NH3. Suggestions of conditions for future observations are provided.

Copper-Catalyzed Electrophilic Amination of Organoaluminum Nucleophiles with O-Benzoyl Hydroxylamines.

PubMed

Zhou, Shuangliu; Yang, Zhiyong; Chen, Xu; Li, Yimei; Zhang, Lijun; Fang, Hong; Wang, Wei; Zhu, Xiancui; Wang, Shaowu

2015-06-19

A copper-catalyzed electrophilic amination of aryl and heteroaryl aluminums with N,N-dialkyl-O-benzoyl hydroxylamines that affords the corresponding anilines in good yields has been developed. The catalytic reaction proceeds very smoothly under mild conditions and exhibits good substrate scope. Moreover, the developed catalytic system is also well suited for heteroaryl aluminum nucleophiles, providing facile access to heteroaryl amines.

PHOSPHORYLATION BY EXTRACTS OF NITROSOMONAS EUROPAEA

PubMed Central

Burge, W. D.; Malavolta, E.; Delwiche, C. C.

1963-01-01

Burge, W. D. (University of California, Berkeley), E. Malavolta, and C. C. Delwiche. Phosphorylation by extracts of Nitrosomonas europaea. J. Bacteriol. 85:106–110. 1963.—Cellfree preparations of Nitrosomonas europaea are capable of oxidizing hydroxylamine, but not ammonium ion, to nitrite. The quantity of nitrite formed by our preparations was, at most, equivalent to only 70% of the hydroxylamine added. Although the preparations had a strong phosphatase activity, resulting in a net loss of organic phosphate during the experimental period, P32-labeled inorganic phosphate was found to be incorporated into the organic fraction, including adenosine triphosphate (ATP) and adenosine diphosphate (ADP). The provision of hydroxylamine as substrate resulted in the formation of nitrite and an increased incorporation of P32 into the organic fraction. It is concluded that the chemosynthetic autotroph Nitrosomonas, in common with certain other autotrophic organisms and heterotrophs, is capable of converting energy released in the oxidation of its inorganic substrate into high-energy phosphate units (ATP and ADP) for the mediation of other energy-requiring reactions. The simultaneous formation of ATP and ADP is interpreted as evidence for an adenylate kinase activity. The preparations used exhibited a considerable endogenous incorporation of P32 into organic phosphate in the absence of added hydroxylamine. Cyanide inhibited both phosphorylation and the oxidation of hydroxylamine. Both the supernatant and particulate fractions of a Nitrosomonas extract subjected to centrifugal fields of 100,000 × g were active in phosphorylation and nitrite formation, but these activities appeared to be uncoupled in the particulate fraction and only partially coupled in the supernatant solution. This most likely reflects a significant endogenous respiration, and not a real lack of coupling between the two reactions. PMID:14016952

Synthesis of densely functionalized enantiopure indolizidines by ring-closing metathesis (RCM) of hydroxylamines from carbohydrate-derived nitrones

PubMed Central

Bonanni, Marco; Marradi, Marco; Cardona, Francesca; Cicchi, Stefano; Goti, Andrea

2007-01-01

Background Indolizidine alkaloids widely occur in nature and display interesting biological activity. This is the reason for which their total synthesis as well as the synthesis of non-natural analogues still attracts the attention of many research groups. To establish new straightforward accesses to these molecules is therefore highly desirable. Results The ring closing metathesis (RCM) of enantiopure hydroxylamines bearing suitable unsaturated groups cleanly afforded piperidine derivatives in good yields. Further cyclization and deprotection of the hydroxy groups gave novel highly functionalized indolizidines. The synthesis of a pyrroloazepine analogue is also described. Conclusion We have developed a new straightforward methodology for the synthesis of densely functionalized indolizidines and pyrroloazepine analogues in 6 steps and 30–60% overall yields from enantiopure hydroxylamines obtained straightforwardly from carbohydrate-derived nitrones. PMID:18076753

Fiberboards treated with N’-N-(1, 8-Naphthalyl) hydroxylamine (NHA-Na), borax, and boric acid

Treesearch

Turgay Akbulut; S. Nami Kartal; Frederick Green

2004-01-01

This paper reports on the physical and mechanical properties and decay and termite resistance of fiberboard panels made from pine and beech treated with N’-N-(1, 8-Naphthalyl) hydroxylamine sodium salt(NHA-Na), borax, and boric acid at varying loadings. The panels were manufactured using 10 percent urea-formaldehyde resin and 1 percent NH4Cl. Mechanical and physical...

Recent developments in Cope-type hydroamination reactions of hydroxylamine and hydrazine derivatives.

PubMed

Beauchemin, André M

2013-11-07

Cope-type hydroaminations are versatile for the direct amination of alkenes, alkynes and allenes using hydroxylamines and hydrazine derivatives. These reactions occur via a concerted, 5-membered cyclic transition state that is the microscopic reverse of the Cope elimination. This article focuses on recent developments, including intermolecular variants, directed reactions, and asymmetric variants using aldehydes as tethering catalysts, and their applications in target-oriented synthesis.

The kinetics and mechanism of the ferrate(VI) oxidation of hydroxylamines.

PubMed

Johnson, Michael D; Hornstein, Brooks J

2003-10-20

Aqueous solutions of potassium ferrate(VI) cleanly and rapidly oxidize hydroxylamine to nitrous oxide, N-methylhydroxylamine to nitrosomethane, N-phenylhydroxylamine to nitrosobenzene, and O-methylhydroxylamine to methanol and nitrogen. The kinetics show first-order behavior with respect to each reactant and a two term component representing acid dependent and independent pathways. A general mechanism involving intermediate formation coupled with a two-electron oxidation is proposed.

The reaction of hydroxylamine with bacteriorhodopsin studied with mutants that have altered photocycles: selective reactivity of different photointermediates.

PubMed Central

Subramaniam, S; Marti, T; Rösselet, S J; Rothschild, K J; Khorana, H G

1991-01-01

The reaction of the retinylidene Schiff base in bacteriorhodopsin (bR) to the water-soluble reagent hydroxylamine is enhanced by greater than 2 orders of magnitude under illumination. We have used this reaction as a probe for changes in Schiff base reactivity during the photocycle of wild-type bR and mutants defective in proton transport. We report here that under illumination at pH 6, the D85N mutant has a 20-fold lower rate and the D212N mutant has a greater than 4-fold higher rate for the light-dependent reaction with hydroxylamine compared with wild-type bR. In contrast, the reactivities of wild-type bR and the D96N and T46V mutants are similar. It has been previously shown that the D96N and T46V replacements have no significant effect on the kinetics of "M" formation but have dramatic effects on rate of the decay of M. We therefore conclude that the hydroxylamine reaction occurs before formation of the M intermediate. Most likely it occurs at the "L" stage of the cycle and reflects increased water accessibility to the Schiff base due to a light-driven change in protein conformation. PMID:2006195

Kinetics and products of the OH radical-initiated reaction of 3-methyl-2-butenal.

PubMed

Tuazon, Ernesto C; Aschmann, Sara M; Nishino, Noriko; Arey, Janet; Atkinson, Roger

2005-06-07

Kinetics and products of the gas-phase reaction of OH radicals with 3-methyl-2-butenal [(CH3)2C=CHCHO] have been investigated at room temperature and atmospheric pressure of air. Using a relative rate method with methacrolein as the reference compound, a rate constant for the reaction of OH radicals with 3-methyl-2-butenal of (6.21 +/- 0.18) x 10(-11) cm3 molecule(-1) s(-1) at 296 +/- 2 K was measured, where the indicated error does not include the uncertainty in the rate constant for the methacrolein reference compound. Products of this reaction were investigated using in situ Fourier transform infrared (FT-IR) spectroscopy and solid phase microextraction (SPME) fibers coated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine for on-fiber derivatization of carbonyl compounds, with subsequent thermal desorption and analysis by gas chromatography. The products observed and the molar formation yields were: glyoxal, 40 +/- 3%; acetone, 74 +/- 6%; 2-hydroxy-2-methylpropanal, 4.6 +/- 0.7%; CO2, 39% initially, decreasing to 30% at greater extents of reaction; peroxyacyl nitrate(s) [RC(O)OONO2], 5-8%, increasing with the extent of reaction and with the sum of the CO2 and RC(O)OONO2 yields being 38 +/- 6%; and organic nitrates [RONO2], 8.5 +/- 2.3%. The formation of these products is readily explained by a reaction mechanism based on those previously formulated for the corresponding reactions of the alpha,beta-unsaturated aldehydes acrolein, crotonaldehyde and methacrolein. Based on the mechanism proposed, at room temperature H-atom abstraction from the CHO group accounts for 40 +/- 6% of the overall reaction, and OH radical addition to the carbon atoms of the C=C bond accounts for 53 +/- 4% of the overall reaction. Hence 93 +/- 8% of the reaction products and pathways are accounted for.

Performance and microbial community analysis of bio-electrocoagulation on simultaneous nitrification and denitrification in submerged membrane bioreactor at limited dissolved oxygen.

PubMed

Li, Liang; Dong, Yihua; Qian, Guangsheng; Hu, Xiaomin; Ye, Linlin

2018-06-01

A pair of Fe-C electrodes was installed in a traditional submerged membrane bioreactor (MBR, Rc), and a novel asynchronous periodic reversal bio-electrocoagulation system (Re) was developed. The simultaneous nitrification and denitrification (SND) performance was discussed under limited dissolved oxygen (DO). Results showed that electrocoagulation enhanced total nitrogen (TN) removal from 59.48% to 75.09% at 1.2 mg/L DO. Additionally, Fe electrode could increase sludge concentration, particle size, and enzyme activities related to nitrogen removal. The enzyme activities of Hydroxylamine oxidoreductase (HAO), Nitrate Reductase (NAR), nitric oxide reductase NOR and nitrous oxide reductase (N 2 OR) in Re were 38.35%, 21.59%, 89.96% and 38.64% higher than Rc, respectively. Moreover, electrocoagulation was advantageous for nitrite accumulation, indicating partial nitrification and denitrification were more easily achieved in Re. Besides, results from high throughput sequencing analysis revealed that electrocoagulation increased the relative abundance of most genera related to nitrogen removal, including Nitrosomonas, Comamonadaceae_unclassified, Haliangium and Denitratisoma. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2013 CFR

2013-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2012 CFR

2012-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2014 CFR

2014-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

Flue gas desulfurization/denitrification using metal-chelate additives

DOEpatents

Harkness, John B. L.; Doctor, Richard D.; Wingender, Ronald J.

1986-01-01

A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

Iron(II)-catalyzed intramolecular aminohydroxylation of olefins with functionalized hydroxylamines.

PubMed

Liu, Guan-Sai; Zhang, Yong-Qiang; Yuan, Yong-An; Xu, Hao

2013-03-06

A diastereoselective aminohydroxylation of olefins with a functionalized hydroxylamine is catalyzed by new iron(II) complexes. This efficient intramolecular process readily affords synthetically useful amino alcohols with excellent selectivity (dr up to > 20:1). Asymmetric catalysis with chiral iron(II) complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.

Fluorescent hydroxylamine derived from the fragmentation of PAMAM dendrimers for intracellular hypochlorite recognition.

PubMed

Wu, Te-Haw; Liu, Ching-Ping; Chien, Chih-Te; Lin, Shu-Yi

2013-08-26

Herein, a promising sensing approach based on the structure fragmentation of poly(amidoamine) (PAMAM) dendrimers for the selective detection of intracellular hypochlorite (OCl(-)) is reported. PAMAM dendrimers were easily disrupted by a cascade of oxidations in the tertiary amines of the dendritic core to produce an unsaturated hydroxylamine with blue fluorescence. Specially, the novel fluorophore was only sensitive to OCl(-), one of reactive oxygen species (ROS), resulting in an irreversible fluorescence turn-off. The fluorescent hydroxylamine was selectively oxidised by OCl(-) to form a labile oxoammonium cation that underwent further degradation. Without using any troublesomely synthetic steps, the novel sensing platform based on the fragmentation of PAMAM dendrimers, can be applied to detect OCl(-) in macrophage cells. The results suggest that the sensing approach may be useful for the detection of intracellular OCl(-) with minimal interference from biological matrixes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nitric oxide is an obligate bacterial nitrification intermediate produced by hydroxylamine oxidoreductase.

PubMed

Caranto, Jonathan D; Lancaster, Kyle M

2017-08-01

Ammonia (NH 3 )-oxidizing bacteria (AOB) emit substantial amounts of nitric oxide (NO) and nitrous oxide (N 2 O), both of which contribute to the harmful environmental side effects of large-scale agriculture. The currently accepted model for AOB metabolism involves NH 3 oxidation to nitrite (NO 2 - ) via a single obligate intermediate, hydroxylamine (NH 2 OH). Within this model, the multiheme enzyme hydroxylamine oxidoreductase (HAO) catalyzes the four-electron oxidation of NH 2 OH to NO 2 - We provide evidence that HAO oxidizes NH 2 OH by only three electrons to NO under both anaerobic and aerobic conditions. NO 2 - observed in HAO activity assays is a nonenzymatic product resulting from the oxidation of NO by O 2 under aerobic conditions. Our present study implies that aerobic NH 3 oxidation by AOB occurs via two obligate intermediates, NH 2 OH and NO, necessitating a mediator of the third enzymatic step.

Major mechanistic differences between the reactions of hydroxylamine with phosphate di- and tri-esters.

PubMed

Medeiros, Michelle; Wanderlind, Eduardo H; Mora, José R; Moreira, Raphaell; Kirby, Anthony J; Nome, Faruk

2013-10-07

Hydroxylamine reacts as an oxygen nucleophile, most likely via its ammonia oxide tautomer, towards both phosphate di- and triesters of 2-hydroxypyridine. But the reactions are very different. The product of the two-step reaction with the triester TPP is trapped by the NH2OH present in solution to generate diimide, identified from its expected disproportionation and trapping products. The reaction with H3N(+)-O(-) shows general base catalysis, which calculations show is involved in the breakdown of the phosphorane addition-intermediate of a two-step reaction. The reactivity of the diester anion DPP(-) is controlled by its more basic pyridyl N. Hydroxylamine reacts preferentially with the substrate zwitterion DPP(±) to displace first one then a second 2-pyridone, in concerted S(N)2(P) reactions, forming O-phosphorylated products which are readily hydrolysed to inorganic phosphate. The suggested mechanisms are tested and supported by extensive theoretical calculations.

Coordination Chemistry of a Strongly-Donating Hydroxylamine with Early Actinides: An Investigation of Redox Properties and Electronic Structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

McSkimming, Alex; Su, Jing; Cheisson, Thibault

Separations of f-block elements are a critical aspect of nuclear waste processing. Redox-based separations offer promise, but challenges remain in stabilizing and differentiating actinides in high oxidation states. The investigation of new ligand types that provide thermodynamic stabilization to high-valent actinides is essential for expanding their fundamental chemistry and to elaborate new separation techniques and storage methods. We report herein the preparation and characterization of Th and U complexes of the pyridyl-hydroxylamine ligand, N-tert-butyl-N-(pyridin-2-yl)hydroxylamine (pyNO–). Electrochemical studies performed on the homoleptic complexes [M(pyNO) 4] (M = Th, U) revealed significant stabilization of the U complex upon one-electron oxidation. The saltmore » [U(pyNO) 4] + was isolated by chemical oxidation of [U(pyNO) 4]; spectroscopic and computational data support assignment as a U V cation.« less

Coordination Chemistry of a Strongly-Donating Hydroxylamine with Early Actinides: An Investigation of Redox Properties and Electronic Structure

DOE PAGES

McSkimming, Alex; Su, Jing; Cheisson, Thibault; ...

2018-03-23

Separations of f-block elements are a critical aspect of nuclear waste processing. Redox-based separations offer promise, but challenges remain in stabilizing and differentiating actinides in high oxidation states. The investigation of new ligand types that provide thermodynamic stabilization to high-valent actinides is essential for expanding their fundamental chemistry and to elaborate new separation techniques and storage methods. We report herein the preparation and characterization of Th and U complexes of the pyridyl-hydroxylamine ligand, N-tert-butyl-N-(pyridin-2-yl)hydroxylamine (pyNO–). Electrochemical studies performed on the homoleptic complexes [M(pyNO) 4] (M = Th, U) revealed significant stabilization of the U complex upon one-electron oxidation. The saltmore » [U(pyNO) 4] + was isolated by chemical oxidation of [U(pyNO) 4]; spectroscopic and computational data support assignment as a U V cation.« less

Interference of nitrite and nitrogen dioxide on mercury and selenium determination by chemical vapor generation atomic absorption spectrometry

NASA Astrophysics Data System (ADS)

Nunes, Dayana Lopes; dos Santos, Eliane Pereira; Barin, Juliano Smanioto; Mortari, Sergio Roberto; Dressler, Valderi Luiz; de Moraes Flores, Érico Marlon

2005-06-01

In this study, a systematic investigation was performed concerning the interference of nitrogen oxides on the determination of selenium and mercury by hydride generation atomic absorption spectrometry (HG AAS) and cold vapor atomic absorption spectrometry (CV AAS). The effect of nitrate, nitrite and NO 2 dissolved in the condensed phase was evaluated. No effect of NO 3- on Se and Hg determination was observed up to 100 mg of sodium nitrate added to the reaction vessel. The Se signal was reduced by about 80% upon the addition of 6.8 mg NO 2-. For Hg, no interference of nitrite was observed up to 20 mg of NO 2-. A complete suppression of the Se signal was observed when gaseous NO 2 was introduced into analytical solutions. For Hg, a signal decrease between 8 and 13% occurred. For Se, bubbling argon or heating the solution was not able to recover the original absorbance values, whereas Hg signals were recovered with these procedures. When gaseous NO 2 was passed directly into the atomizer, Se signals decreased similarly to when NO 2 was bubbled in analytical solutions. The addition of urea, hydroxylamine hydrochloride and sulfamic acid (SA) was investigated to reduce the NO 2 effect in sample digests containing residual NO 2, but only SA was effective in reducing the interference. Based on the results, it is possible to propose the use of SA to prevent interferences in Se and Hg determinations by HG AAS and CV AAS, respectively.

Optical and Transport Properties of Energetic Materials

NASA Astrophysics Data System (ADS)

Choi, Chang Sun

1990-01-01

The densities of Hydroxyl ammonium nitrate (HAN) based fast reacting liquids were measured as a function of pressure (up to 4.83 kbars) at several temperatures and the results of density measurements were fit to the Tait equation. Also the shear viscosities of this liquid were measured as a function of both pressure and temperature. The free volume model was applied to explain behavior of the shear viscosity with the assumption that only the reference temperature (T_0) in the Fulcher (1925), WLF (Williams, Landel, and Ferry) and Angell equations depends on pressure. The general relation to predict viscosity of this liquid at any temperature and pressure was derived and the difference between expected and measured values are about 5%. The phase diagrams of the HAN solution, Triethanol ammonium nitrate (TEAN) solution and LP-1845 were obtained through Differential Scanning Calorimetry (DSC) measurements. The TEAN solution has a eutectic temperature in the vicinity of 260^circK. The measured phase diagrams are in good agreement with the calculated phase diagrams. The TEAN solutions show a large supercooling effect. Some phase separation was observed in the TEAN solutions and this separation was believed to be due to eutectic composition of the TEAN solution. The expected freezing temperature of LP-1845 was almost the same with the calculated T_0 from the viscosity data. Raman spectra from the HAN solution, TEAN solution and LP-1845 were measured. Every peak in the spectra was assigned. These solutions show various interactions, such as ion-ion pairing and ion-water interaction. The strongest peak was a NO_3^- symmetric stretch mode at 1050 cm^{-1}. The time correlation functions were calculated from the Raman spectra of the 1050 cm^{-1} peak. The correlation time, which can be calculated from the linewidth, become shorter with decreasing temperatures and with increasing concentrations. The Kubo's stochastic theory explains the correlation functions very well if the solution is relatively dilute. The pressure dependence of the reaction rate was estimated by using the density data and Raman peak shift data.

Flue gas desulfurization/denitrification using metal-chelate additives

DOEpatents

Harkness, J.B.L.; Doctor, R.D.; Wingender, R.J.

1985-08-05

A method of simultaneously removing SO/sub 2/ and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO/sub 2/ and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled. 3 figs.

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2012 CFR

2012-07-01

... 4.0 with pH 4.0 buffer and pH 7 with pH 7.0 buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.... 3.8Timer. 4. Reagents 4.1Standardized 1.0 N sodium hydroxide solution. 4.2Hydroxylamine.... Start the timer. 5.6Stir for 5 minutes. Titrate to pH 4.0 with standardized 1.0 N sodium hydroxide...

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2011 CFR

2011-07-01

..., readable to 0.01 g or better. 3.2pH meter, standardized to pH 4.0 with pH 4.0 buffer and pH 7 with pH 7.0... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... stirrer. Confirm that the resin has dissolved. 5.4Adjust the resin/solvent solution to pH 4.0, using the...

Hydrolysis and nucleophilic substitution of model and ultimate carcinogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helmick, J.S.

1992-01-01

The hydrolysis reaction of the Model Carcinogen O-pivaloyl-N-(4-chlorophenyl)hydroxylamine in aqueous buffer (pH 7.0-10.0) proceeds by was of a nitrenium ion intermediate. The products formed from this process are predominately 2,4-dichloroaniline, and 2-hydroxy-4-chloro-pivalanilide. At pH 10-13 the rate becomes dependent upon hydroxide. The product that is formed is 4-chlorophenylhydroxylamine. 4-Chlorophenyl-hydroxylamine is formed by basic ester hydrolysis determined by an [sup 18]O GC-MS experiment. The reaction of O-pivaloyl-N-(4-chlorophenyl)hydroxylamine in an aqueous diethylamine (pH 11.3) buffer gave 4-chlorophenyl-N,N-diethylhydrazine as the substitution product in a 16% yield. The reaction of O-pivaloyl-N-(4-methylphenyl)hydroxylamine with diethylamine gave a 1% yield of the hydrazine product. The reaction ofmore » N,N-dimethylanline and aniline with ring-substituted O-pivaloyl-N-arylhydroxylamines in MeOH generates products of nucleophilic attack on the nitrogen of the hydroxylamine derivative. The hydrolysis of the ultimate carcinogen N-(sulfonatooxy)-N-4-aminobiphenyl proceeds by two consecutive pseudo-first-order processes and generates predominately a product of nucleophilic attack by chloride ion at the ortho position of the aromatic ring. A labile intermediate identified as N-acetypl-4-hydroxy-4-phenyl-2,5-cyclohexadienone imine has been detected by NMR. This intermediate rearranges to form 4-hydroxy-3-phenylacetanilide. The hydrolysis of N-benzoyl-4-hydroxy-4-hydroxy-4-phenyl-2,5-cyclohexadienone imine proceeds by way of two consecutive pseudo-first-order processes. The hydrolysis of N-benzoyl-4-methoxy-4-phenyl-2,5-cyclohexadienone imine also proceeds by two consecutive pseudo-first-order processes. Spectroscopic evidence of two diastereomeric intermediates formed from the hydrolysis of the N-benzoyl imines were tentatively identified as N-benzoyl-N-hydroxy-4-hydroxy-4-phenyl-2,5-cyclohexadienone imine.« less

Cytochrome b5 and NADH cytochrome b5 reductase: genotype-phenotype correlations for hydroxylamine reduction.

PubMed

Sacco, James C; Trepanier, Lauren A

2010-01-01

NADH cytochrome b5 reductase (b5R) and cytochrome b5 (b5) catalyze the reduction of sulfamethoxazole hydroxylamine (SMX-HA), which can contribute to sulfonamide hypersensitivity, to the parent drug sulfamethoxazole. Variability in hydroxylamine reduction could thus play a role in adverse drug reactions. The aim of this study was to characterize variability in SMX-HA reduction in 111 human livers, and investigate its association with single nucleotide polymorphisms (SNPs) in b5 and b5R cDNA. Liver microsomes were assayed for SMX-HA reduction activity, and b5 and b5R expression was semiquantified by immunoblotting. The coding regions of the b5 (CYB5A) and b5R (CYB5R3) genes were resequenced. Hepatic SMX-HA reduction displayed a 19-fold range of individual variability (0.06-1.11 nmol/min/mg protein), and a 17-fold range in efficiency (Vmax/Km) among outliers. SMX-HA reduction was positively correlated with b5 and b5R protein content (P<0.0001, r=0.42; P=0.01, r=0.23, respectively), and expression of both proteins correlated with one another (P<0.0001; r=0.74). A novel cSNP in CYB5A (S5A) was associated with very low activity and protein expression. Two novel CYB5R3 SNPs, R59H and R297H, displayed atypical SMX-HA reduction kinetics and decreased SMX-HA reduction efficiency. These studies indicate that although novel cSNPs in CYB5A and CYB5R3 are associated with significantly altered protein expression and/or hydroxylamine reduction activities, these low-frequency cSNPs seem to only minimally impact overall observed phenotypic variability. Work is underway to characterize polymorphisms in other regions of these genes to further account for individual variability in hydroxylamine reduction.

Simple assembly of polysubstituted pyrazoles and isoxazoles via ring closure-ring opening domino reaction of 3-acyl-4,5-dihydrofurans with hydrazines and hydroxylamine.

PubMed

Chagarovskiy, Alexey O; Budynina, Ekaterina M; Ivanova, Olga A; Rybakov, Victor B; Trushkov, Igor V; Melnikov, Mikhail Ya

2016-03-14

A convenient general approach to 2-(pyrazol-4-yl)- and 2-(isoxazol-4-yl)ethanols based on the Brønsted acid-initiated reaction of 3-acyl-4,5-dihydrofurans with hydrazines or hydroxylamine was developed. Further transformation of the alcohol moiety in 2-(pyrazolyl)ethanols affording 2-(pyrazolyl)ethylamine as potent bioactive compounds as well as pyrazole-substituted derivatives of antitumor alkaloid crispine A was elaborated.

Visible-light-promoted redox neutral C-H amidation of heteroarenes with hydroxylamine derivatives.

PubMed

Qin, Qixue; Yu, Shouyun

2014-07-03

A room temperature redox neutral direct C-H amidation of heteroarenes has been achieved. Hydroxylamine derivatives, which are easily accessed, have been employed as tunable nitrogen sources. These reactions were enabled by a visible-light-promoted single-electron transfer pathway without a directing group. A variety of heteroarenes, such as indoles, pyrroles, and furans, could go through this amidation with high yields (up to 98%). These reactions are highly regioselective, and all the products were isolated as a single regioisomer.

The Advancing State of AF-M315E Technology

NASA Technical Reports Server (NTRS)

Masse, Robert; Spores, Ronald A.; McLean, Chris

2014-01-01

The culmination of twenty years of applied research in hydroxyl ammonium nitrate (HAN)-based monopropellants, the NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) will achieve the first on-orbit demonstration of an operational AF-M315E green propellant propulsion system by the end of 2015. Following an contextual overview of the completed flight design of the GPIM propellant storage and feed system, results of first operation of a flight-representative heavyweight 20-N engineering model thruster (to be conducted in mid-2014) are presented with performance comparisons to prior lab model (heavyweight) test articles.

A simple and sensitive method for the determination of hydroxylamine in fresh-water samples using hypochlorite followed by gas chromatography.

PubMed

Seike, Yasushi; Fukumori, Ryoko; Senga, Yukiko; Oka, Hiroki; Fujinaga, Kaoru; Okumura, Minoru

2004-01-01

A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively.

EPR Detection of Cellular and Mitochondrial Superoxide Using Cyclic Hydroxylamines

PubMed Central

Dikalov, Sergey I.; Kirilyuk, Igor A.; Voinov, Maxim; Grigor’ev, Igor A.

2014-01-01

Superoxide (O2•) has been implicated in the pathogenesis of many human diseases but detection of the O2• radicals in biological systems is limited due to inefficiency of O2• spin trapping and lack of site-specific information. In this work we studied production of extracellular, intracellular and mitochondrial O2• in neutrophils, cultured endothelial cells and isolated mitochondria using new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O2• producing stable nitroxides and allowed site-specific O2• detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O2•. Inhibition of EPR signal by SOD2 overexpression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O2• both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected increase in cytoplasm O2• stimulated by PMA but only CM-H and mitoTEMPO-H showed increase in rotenone-induced mitochondrial O2•. These data show that new set of hydroxylamine spin probes provide unique information about site-specific production of O2• radical in extracellular or intracellular compartments, cytoplasm or mitochondria. PMID:21128732

Multicomponent Reaction of Z-Chlorooximes, Isocyanides, and Hydroxylamines as Hypernucleophilic Traps. A One-Pot Route to Aminodioximes and Their Transformation into 5-Amino-1,2,4-oxadiazoles by Mitsunobu-Beckmann Rearrangement.

PubMed

Mercalli, Valentina; Massarotti, Alberto; Varese, Monica; Giustiniano, Mariateresa; Meneghetti, Fiorella; Novellino, Ettore; Tron, Gian Cesare

2015-10-02

Synthetically useful aminodioximes are prepared via a novel three-component reaction among Z-chlorooximes, isocyanides, and hydroxylamines by exploiting the preferential attack of isocyanides to nitrile N-oxides via a [3 + 1] cycloaddition reaction. The results of quantum mechanical studies of the reaction mechanism are also discussed. Furthermore, the one-pot conversion of aminodioximes to 1,2,3-oxadiazole-5-amines via Mitsunobu-Beckmann rearrangement is reported for the first time.

[Glycosilated derivatives of substituted hydroxylamine. II. Phase transfer synthesis and investigation of glycosyl transfer reaction of glucosaminides of substituted hydroxylavine].

PubMed

Kur'ianov, V O; Lushchik, A A; Chupakhina, T A

2013-01-01

1-(2-Acetamido-3,4,6,-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyloxy)-benzotriazole reacted in boiling dichloromethane, in the presence of Luis acids as a promotors with primary and secondary aliphatic and cycloaliphatic alcohols and diisopropilidene galactose with alkyl-O-1,2-trans-glucosaminides formation. It was shown that the other glucosaminides of substituted hydroxylamine are not participated in this reaction. Structures of glucosaminides were identify by 1H-NMR-spectroscopy and comparison with known compounds.

1,4-hydroxycarbonyl products of the OH radical initiated reactions of C5-C8 n-alkanes in the presence of NO.

PubMed

Reisen, Fabienne; Aschmann, Sara M; Atkinson, Roger; Arey, Janet

2005-06-15

Alkanes account for approximately 50% of nonmethane organic compounds present in urban atmospheres. Previous studies have shown that hydroxycarbonyls are important products ofthe OH radical initiated reactions of > or = C5 n-alkanes, but isomer-specific identifications and quantifications of these products have not been carried out. In this work, we have used solid-phase microextraction fibers precoated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine for on-fiber derivatization of carbonyl-containing compounds with subsequent analyses by combined gas chromatography-mass spectrometry (GC-MS) and GC with flame ionization detection (GC-FID). GC-MS analyses showed the presence of the oximes of 5-hydroxy-2-pentanone and 4-hydroxypentanal from the n-pentane reaction; 5-hydroxy-2-hexanone, 6-hydroxy-3-hexanone, and 4-hydroxyhexanal from the n-hexane reaction; 5-hydroxy-2-heptanone, 6-hydroxy-3-heptanone, 1-hydroxy-4-heptanone, and 4-hydroxyheptanal from the n-heptane reaction; and 5-hydroxy-2-octanone, 6-hydroxy-3-octanone, 7-hydroxy-4-octanone, and 4-hydroxyoctanal from the n-octane reaction. The formation yields of these 1,4-hydroxycarbonyls were determined from GC-FID analyses. By use of the yields of 1,4-hydroxycarbonyls formed from n-hexane, n-heptane, and n-octane at 50% relative humidity (and those from n-pentane at both 5 and 50% relative humidity), then formation of 1,4-hydroxycarbonyls accounts for 54% of the reaction products from n-pentane, 57% from n-hexane, 51% from n-heptane, and 53% from n-octane. Combined with previously measured yields of carbonyls, alkyl nitrates, and hydroxyalkyl nitrates, we can now accountfor approximately 74-118% of the products formed from the n-pentane through n-octane reactions.

Rapid chlorophyll a fluorescence transient of Lemna gibba leaf as an indication of light and hydroxylamine effect on photosystem II activity.

PubMed

Dewez, David; Ali, Nadia Ait; Perreault, François; Popovic, Radovan

2007-05-01

Rapid chlorophyll fluorescence transient induced by saturating flash (3000 micromol of photons m-2 s-1) was investigated when Lemna gibba had been exposed to light (100 micromol of photons m-2 s-1) causing the Kautsky effect or in low light intensity unable to trigger PSII photochemistry. Measurements were made by using, simultaneously, a pulse amplitude modulated fluorometer and plant efficiency analyzer system, either on non-treated L. gibba leaf or those treated with different concentrations of hydroxylamine (1-50 mM) causing gradual inhibition of the water splitting system. When any leaf was exposed to continuous light during the Kautsky effect, a rapid fluorescence transient may reflect current activity of photosystem II within the photosystem II complex. Under those conditions, a variation of transition steps appearing over time was related to a drastic change to the photosystem II functional properties. This value indicated that the energy dissipation through non-photochemical pathways was undergoing extreme change. The change of rapid fluorescence transient, induced under continuous light, when compared to those obtained under very low light intensity, confirmed the ability of photosystem II to be capable to undergo rapid adaptation lasting about two minutes. When the water splitting system was inhibited and electron donation partially substituted by hydroxylamine, the adaptation ability of photosystem II to different light conditions was lost. In this study, the change of rapid fluorescence kinetic and transient appearing over time was shown to be a good indication for the change of the functional properties of photosystem II induced either by light or by hydroxylamine.

N-Hydroxylation of dapsone by multiple enzymes of cytochrome P450: implications for inhibition of haemotoxicity.

PubMed Central

Gill, H J; Tingle, M D; Park, B K

1995-01-01

1. The adverse reactions associated with the administration of dapsone are believed to be caused by metabolism to its hydroxylamine. Previous reports suggest that CYP3A4 is responsible for this biotransformation [1]. 2. Data presented in this paper illustrate the involvement of more than one cytochrome P450 enzyme in dapsone hydroxylamine formation using human liver microsomes. Eadie-Hofstee plots demonstrated bi-phasic kinetics in several livers. No correlation could be established between hydroxylamine formation and CYP3A concentrations in six human livers (r = -0.47; P = 0.34). 3. Studies with low molecular weight inhibitors illustrate the importance of CYP2C9 and CYP3A in dapsone N-hydroxylation. 4. Differential sensitivity of dapsone N-hydroxylation to selective CYP inhibitors indicated that the contribution of individual CYP enzymes varies between livers. Selective inhibition ranged from 6.8 to 44.1% by 5 microM ketoconazole, and from 24.0 to 68.4% by 100 microM sulphaphenazole. The extent of inhibition, by either ketoconazole or sulphaphenazole was dependent on the CYP3A content of the liver. 5. The levels of expression of these cytochrome P450 enzymes may be an important determinant of individual susceptibility to the toxic effects of dapsone, and may influence the ability of an enzyme inhibitor to block dapsone toxicity in vivo. Because of the inability to produce complete inhibition, selective CYP inhibitors are unlikely to offer any clinical advantage over cimetidine in decreasing dapsone hydroxylamine formation in vivo. PMID:8703658

Sequential Metabolism of Secondary Alkyl Amines to Metabolic-Intermediate Complexes: Opposing Roles for the Secondary Hydroxylamine and Primary Amine Metabolites of Desipramine, (S)-Fluoxetine, and N-Desmethyldiltiazem

PubMed Central

Hanson, Kelsey L.; VandenBrink, Brooke M.; Babu, Kantipudi N.; Allen, Kyle E.; Nelson, Wendel L.

2010-01-01

Three secondary amines desipramine (DES), (S)-fluoxetine [(S)-FLX], and N-desmethyldiltiazem (MA) undergo N-hydroxylation to the corresponding secondary hydroxylamines [N-hydroxydesipramine, (S)-N-hydroxyfluoxetine, and N-hydroxy-N-desmethyldiltiazem] by cytochromes P450 2C11, 2C19, and 3A4, respectively. The expected primary amine products, N-desmethyldesipramine, (S)-norfluoxetine, and N,N-didesmethyldiltiazem, are also observed. The formation of metabolic-intermediate (MI) complexes from these substrates and metabolites was examined. In each example, the initial rates of MI complex accumulation followed the order secondary hydroxylamine > secondary amine ≫ primary amine, suggesting that the primary amine metabolites do not contribute to formation of MI complexes from these secondary amines. Furthermore, the primary amine metabolites, which accumulate in incubations of the secondary amines, inhibit MI complex formation. Mass balance studies provided estimates of the product ratios of N-dealkylation to N-hydroxylation. The ratios were 2.9 (DES-CYP2C11), 3.6 [(S)-FLX-CYP2C19], and 0.8 (MA-CYP3A4), indicating that secondary hydroxylamines are significant metabolites of the P450-mediated metabolism of secondary alkyl amines. Parallel studies with N-methyl-d3-desipramine and CYP2C11 demonstrated significant isotopically sensitive switching from N-demethylation to N-hydroxylation. These findings demonstrate that the major pathway to MI complex formation from these secondary amines arises from N-hydroxylation rather than N-dealkylation and that the primary amines are significant competitive inhibitors of MI complex formation. PMID:20200233

Oxidation of hydroxylamine by cytochrome P-460 of the obligate methylotroph Methylococcus capsulatus Bath.

PubMed Central

Zahn, J A; Duncan, C; DiSpirito, A A

1994-01-01

An enzyme capable of the oxidation of hydroxylamine to nitrite was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The absorption spectra in cell extracts, electron paramagnetic resonance spectra, molecular weight, covalent attachment of heme group to polypeptide, and enzymatic activities suggest that the enzyme is similar to cytochrome P-460, a novel iron-containing protein previously observed only in Nitrosomonas europaea. The native and subunit molecular masses of the M. capsulatus Bath protein were 38,900 and 16,390 Da, respectively; the isoelectric point was 6.98. The enzyme has approximately one iron and one copper atom per subunit. The electron paramagnetic resonance spectrum of the protein showed evidence for a high-spin ferric heme. In contrast to the enzyme from N. europaea, a 13-nm blue shift in the soret band of the ferrocytochrome (463 nm in cell extracts to 450 nm in the final sample) occurred during purification. The amino acid composition and N-terminal amino acid sequence of the enzyme from M. capsulatus Bath was similar but not identical to those of cytochrome P-460 of N. europaea. In cell extracts, the identity of the biological electron acceptor is as yet unestablished. Cytochrome c-555 is able to accept electrons from cytochrome P-460, although the purified enzyme required phenazine methosulfate for maximum hydroxylamine oxidation activity (specific activity, 366 mol of O2 per s per mol of enzyme). Hydroxylamine oxidation rates were stimulated approximately 2-fold by 1 mM cyanide and 1.5-fold by 0.1 mM 8-hydroxyquinoline. Images PMID:7928947

EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines.

PubMed

Dikalov, Sergey I; Kirilyuk, Igor A; Voinov, Maxim; Grigor'ev, Igor A

2011-04-01

Superoxide (O₂ⁱ⁻) has been implicated in the pathogenesis of many human diseases, but detection of the O(2)(•-) radicals in biological systems is limited due to inefficiency of O₂ⁱ⁻ spin trapping and lack of site-specific information. This work studied production of extracellular, intracellular and mitochondrial O₂ⁱ⁻ in neutrophils, cultured endothelial cells and isolated mitochondria using a new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O₂ⁱ⁻, producing stable nitroxides and allowing site-specific cO₂ⁱ⁻ detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O₂ⁱ⁻. Inhibition of EPR signal by SOD2 over-expression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O₂ⁱ⁻ both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected an increase in cytoplasm O₂ⁱ⁻ stimulated by PMA, but only CM-H and mitoTEMPO-H showed an increase in rotenone-induced mitochondrial O₂ⁱ⁻. These data show that a new set of hydroxylamine spin probes provide unique information about site-specific production of the O₂ⁱ⁻ radical in extracellular or intracellular compartments, cytoplasm or mitochondria.

Sequential metabolism of secondary alkyl amines to metabolic-intermediate complexes: opposing roles for the secondary hydroxylamine and primary amine metabolites of desipramine, (s)-fluoxetine, and N-desmethyldiltiazem.

PubMed

Hanson, Kelsey L; VandenBrink, Brooke M; Babu, Kantipudi N; Allen, Kyle E; Nelson, Wendel L; Kunze, Kent L

2010-06-01

Three secondary amines desipramine (DES), (S)-fluoxetine [(S)-FLX], and N-desmethyldiltiazem (MA) undergo N-hydroxylation to the corresponding secondary hydroxylamines [N-hydroxydesipramine, (S)-N-hydroxyfluoxetine, and N-hydroxy-N-desmethyldiltiazem] by cytochromes P450 2C11, 2C19, and 3A4, respectively. The expected primary amine products, N-desmethyldesipramine, (S)-norfluoxetine, and N,N-didesmethyldiltiazem, are also observed. The formation of metabolic-intermediate (MI) complexes from these substrates and metabolites was examined. In each example, the initial rates of MI complex accumulation followed the order secondary hydroxylamine > secondary amine > primary amine, suggesting that the primary amine metabolites do not contribute to formation of MI complexes from these secondary amines. Furthermore, the primary amine metabolites, which accumulate in incubations of the secondary amines, inhibit MI complex formation. Mass balance studies provided estimates of the product ratios of N-dealkylation to N-hydroxylation. The ratios were 2.9 (DES-CYP2C11), 3.6 [(S)-FLX-CYP2C19], and 0.8 (MA-CYP3A4), indicating that secondary hydroxylamines are significant metabolites of the P450-mediated metabolism of secondary alkyl amines. Parallel studies with N-methyl-d(3)-desipramine and CYP2C11 demonstrated significant isotopically sensitive switching from N-demethylation to N-hydroxylation. These findings demonstrate that the major pathway to MI complex formation from these secondary amines arises from N-hydroxylation rather than N-dealkylation and that the primary amines are significant competitive inhibitors of MI complex formation.

Copper-Catalysed Aminoboration of Vinylarenes with Hydroxylamine Esters-A Computational Mechanistic Study.

PubMed

Tobisch, Sven

2017-12-14

An in-depth computational probe of the copper-mediated formal aminoboration of β-alkylstyrenes with bis(pinacolato)diboron B 2 pin 2 and an archetype hydroxylamine ester by a dppbz-ligated {P^P}Cu I boryl catalyst (dppbz≡{P^P}≡1,2-bis(diphenylphosphino)benzene) is presented. This first comprehensive computational study of the copper-mediated formal aminoboration utilising an electrophilic strategy has identified the most accessible pathway for productive catalysis. The mechanistic picture derived from smooth energy profiles acquired by employing a reliable computational protocol applied to a realistic catalyst model conforms to all available experimental data. The high degree of regio- and stereoselectivity achieved in syn-borylcupration and Umpolung electrophilic amination is instrumental to the exclusive generation of the (syn)-β-aminoalkylborane product. On the one hand, syn-borylcupration furnishes exclusively β-borylalkylcopper nucleophile upon boryl addition onto the vinylarene β-carbon. Its subsequent approach by the hydroxylamine electrophile to deliver the product with the release of {P^P}Cu I benzoate favours a stepwise stereoretentive S N 2-type oxidative addition/N-C bond-forming reductive elimination sequence. The copper benzoate species represents the catalyst resting state, and its transformation into the catalytically active borylcopper species upon salt metathesis with Li(OtBu) base and transmetallation with B 2 pin 2 is turnover limiting. Electronically modified β-alkylstyrenes featuring a para-CF 3 substituted phenyl ring render the borylcupration faster, and more electron-rich hydroxylamine agents decelerate the electrophilic amination. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metatranscriptomic Analysis of Groundwater Reveals an Active Anammox Bacterial Population

NASA Astrophysics Data System (ADS)

Jewell, T. N. M.; Karaoz, U.; Thomas, B. C.; Banfield, J. F.; Brodie, E.; Williams, K. H.; Beller, H. R.

2014-12-01

Groundwater is a major natural resource, yet little is known about the contribution of microbial anaerobic ammonium oxidation (anammox) activity to subsurface nitrogen cycling. During anammox, energy is generated as ammonium is oxidized under anaerobic conditions to dinitrogen gas, using nitrite as the final electron acceptor. This process is a global sink for fixed nitrogen. Only a narrow range of monophyletic bacteria within the Planctomycetes carries out anammox, and the full extent of their metabolism, and subsequent impact on nitrogen cycling and microbial community structure, is still unknown. Here, we employ a metatranscriptomic analysis on enriched mRNA to identify the abundance and activity of a population of anammox bacteria within an aquifer at Rifle, CO. Planktonic biomass was collected over a two-month period after injection of up to 1.5 mM nitrate. Illumina-generated sequences were mapped to a phylogenetically binned Rifle metagenome database. We identified transcripts for genes with high protein sequence identities (81-98%) to those of anammox strain KSU-1 and to two of the five anammox bacteria genera, Brocadia and Kuenenia, suggesting an active, if not diverse, anammox population. Many of the most abundant anammox transcripts mapped to a single scaffold, indicative of a single dominant anammox species. Transcripts of the genes necessary for the anammox pathway were present, including an ammonium transporter (amtB), nitrite/formate transporter, nitrite reductase (nirK), and hydrazine oxidoreductase (hzoB). The form of nitrite reductase encoded by anammox is species-dependent, and we only identified nirK, with no evidence of anammox nirS. In addition to the anammox pathway we saw evidence of the anammox bacterial dissimilatory nitrate reduction to ammonium pathway (narH, putative nrfA, and nrfB), which provides an alternate means of generating substrates for anammox from nitrate, rather than relying on an external pool. Transcripts for hydroxylamine oxidoreductase (HAO) were abundant and more similar to known anammox HAO genes than those used in aerobic ammonia oxidation. The elevated levels of anammox transcripts suggest that anammox may play a significant role in nitrogen cycling within groundwater systems.

Differentiation by hydroquinone of relaxations induced by exogenous and endogenous nitrates in non-vascular smooth muscle: role of superoxide anions.

PubMed Central

Hobbs, A. J.; Tucker, J. F.; Gibson, A.

1991-01-01

1. The influence of hydroquinone on relaxations induced by nitric oxide (NO), nitrovasodilator drugs, and non-adrenergic, non-cholinergic (NANC) field stimulation has been investigated in three tissues in which endogenous nitrates have been implicated in the NANC response; the mechanism of action of hydroquinone was also studied. 2. In mouse anococcygeus, hydroquinone (10-100 microM) produced a concentration-dependent inhibition of relaxations induced by 15 microM NO. Hydroquinone, 100 microM, which reduced responses to NO by 85%, had no effect on relaxations induced by NANC field stimulation (10 Hz; 20s trains), hydroxylamine (10 microM), sodium nitroprusside (1 microM) or sodium azide (20 microM). 3. In guinea-pig trachea, 100 microM hydroquinone reduced relaxations to 150 microM NO by 75%, but had no effect on those to NANC stimulation (10 Hz; 30 s trains) or sodium azide (5 microM). 4. In rat gastric fundus, 100 microM hydroquinone reduced relaxations to 1 microM NO by 85%, but had no effect on those to NANC stimulation (0.5 Hz; 15 s trains) or sodium azide (2 microM). 5. Superoxide dismutase (SOD; 50 u ml-1) had no effect on relaxations of the mouse anococcygeus in response to 15 microM NO or 10 Hz NANC stimulation. Further, the inhibition of responses to NO by hydroquinone was unaffected in the presence of SOD. 6. Hydroquinone (10-100 microM) failed to generate superoxide anions, as detected by a chemiluminescent assay. However, 100 microM hydroquinone, like SOD (50 u ml-1), produced almost complete inhibition of superoxide anion chemiluminescence induced by xanthine (500 microM): xanthine oxidase (0.07 u ml-1). 7. It is concluded that, in our system, hydroquinone inhibits NO by acting as a free radical scavenger rather than by generating superoxide anions. The ability of hydroquinone to block relaxations to NO, but not NANC stimulation, may suggest that the endogenous nitrate substance released by these NANC nerves may not be free NO, but may be an NO-containing, or NO-generating, molecule. PMID:1665746

E2P phosphoforms of Na,K-ATPase. I. Comparison of phosphointermediates formed from ATP and Pi by their reactivity toward hydroxylamine and vanadate.

PubMed

Fedosova, N U; Cornelius, F; Klodos, I

1998-09-29

The properties of Na,K-ATPase phosphoenzymes formed either from ATP in the presence of Mg2+ and Na+ or from Pi in the absence of alkali cations were investigated by biochemical methods and spectrofluorometry employing the styryl dye RH421. We characterized the phosphoenzyme species by their reaction to N-methyl hydroxylamine, which attacks specifically the protein-phosphate bond. We studied reactions of the phospho- and dephospho-enzymes with vanadate, which is a transition-state analogue of phosphate in this enzyme. On the basis of substantial differences in the properties of the phosphoenzyme species formed either from ATP or Pi, especially in their reactivity to N-methyl hydroxylamine, it is suggested that the two phosphoenzyme species are two subconformations of the E2P phosphoform. Analysis of the RH421 fluorescence responses under a variety of experimental conditions and comparing different enzyme sources suggested that the increase of RH421 fluorescence induced by inorganic phosphate in the absence of alkali cations is associated with the formation of the covalent acyl-phosphate bond.

Electrochemical Fabrication of Nanostructures on Porous Silicon for Biochemical Sensing Platforms.

PubMed

Ko, Euna; Hwang, Joonki; Kim, Ji Hye; Lee, Joo Heon; Lee, Sung Hwan; Tran, Van-Khue; Chung, Woo Sung; Park, Chan Ho; Choo, Jaebum; Seong, Gi Hun

2016-01-01

We present a method for the electrochemical patterning of gold nanoparticles (AuNPs) or silver nanoparticles (AgNPs) on porous silicon, and explore their applications in: (1) the quantitative analysis of hydroxylamine as a chemical sensing electrode and (2) as a highly sensitive surface-enhanced Raman spectroscopy (SERS) substrate for Rhodamine 6G. For hydroxylamine detection, AuNPs-porous silicon can enhance the electrochemical oxidation of hydroxylamine. The current changed linearly for concentrations ranging from 100 μM to 1.32 mM (R(2) = 0.995), and the detection limit was determined to be as low as 55 μM. When used as SERS substrates, these materials also showed that nanoparticles decorated on porous silicon substrates have more SERS hot spots than those decorated on crystalline silicon substrates, resulting in a larger SERS signal. Moreover, AgNPs-porous silicon provided five-times higher signal compared to AuNPs-porous silicon. From these results, we expect that nanoparticles decorated on porous silicon substrates can be used in various types of biochemical sensing platforms.

Neuroprotection and lifespan extension in Ppt1−/− mice by NtBuHA: therapeutic implications for INCL

PubMed Central

Sarkar, Chinmoy; Chandra, Goutam; Peng, Shyiong; Zhang, Zhongjian; Liu, Aiyi; Mukherjee, Anil B.

2013-01-01

Infantile neuronal ceroid lipofuscinosis (INCL) is a devastating childhood neurodegenerative lysosomal storage disease (LSD) that has no effective treatment. It is caused by inactivating mutations in the palmitoyl-protein thioesterase-1 (PPT1) gene. PPT1-deficiency impairs the cleavage of thioester linkage in palmitoylated proteins (constituents of ceroid), preventing degradation by lysosomal hydrolases. Consequently, accumulation of lysosomal ceroid leads to INCL. Thioester linkage is cleaved by nucleophilic attack. Hydroxylamine, a potent nucleophilic cellular metabolite, may have therapeutic potential for INCL but its toxicity precludes clinical application. Here we report that a hydroxylamine-derivative, N-(tert-Butyl) hydroxylamine (NtBuHA), is non-toxic, cleaves thioester linkage in palmitoylated proteins and mediates lysosomal ceroid depletion in cultured cells from INCL patients. Importantly, in Ppt1−/− mice, which mimic INCL, NtBuHA crossed the blood-brain-barrier, depleted lysosomal ceroid, suppressed neuronal apoptosis, slowed neurological deterioration and extended lifespan. Our findings provide the proof of concept that thioesterase-mimetic and antioxidant small molecules like NtBuHA are potential drug-targets for thioesterase deficiency diseases like INCL. PMID:24056696

Nitrogen chemistry on dust grains: the formation of hydroxylamine, precursor to glycine

NASA Astrophysics Data System (ADS)

Vidali, Gianfranco; Lemaire, Jean Louis; Shi, Jianming; Hopkins, Tyler; Garrod, Rob; He, Jiao

2015-08-01

In ices coating dust grains in molecular clouds, nitrogen-containing molecules - mostly NH3 - are present in sizable quantity, up to 15-20% with respect to water ice, the largest component. We studied the oxidation of ammonia in a series of experiments using beams of oxygen and ammonia in various configurations (co-deposition and sequential deposition with various NH3:O ratios). We detected the formation of hydroxylamine (NH2OH) and other products, depending on the degree of oxidation. A simulation of a dense cloud with input from experimental data shows that on and in ices at 14 K and with modest activation energy for reaction, NH2OH is easily formed and its abundance never falls below a tenth of the NH3 abundance. Strategies for detection of hydroxylamine in the ISM will be presented.This work is supported by the NSF Astronomy and Astrophysics Division (grant No.1311958 to G.V.). R.T.G. acknowledges the support of the NASA Astrophysics Theory Program (grant No. NNX11AC38G).

Formation of Hydroxylamine from Ammonia and Hydroxyl Radicals

NASA Astrophysics Data System (ADS)

Krim, Lahouari; Zins, Emilie-Laure

2014-06-01

In the interstellar medium, as well as in icy comets, ammonia may be a crucial species in the first step toward the formation of amino-acids and other prebiotic molecules such as hydroxylamine (NH2OH). It is worth to notice that the NH3/H2 ratio in the ISM is 3 10-5 compared the H2O/H2 one which is only 7 10-5. Using either electron-UV irradiations of water-ammonia ices or successive hydrogenation of solid nitric oxide, laboratory experiments have already shown the feasibility of reactions that may take place on the surface of ice grains in molecular clouds, and may lead to the formation of this precursor. Herein is proposed a new reaction pathway involving ammonia and hydroxyl radicals generated in a microwave discharge. Experimental studies, at 3 and 10 K, in solid phase as well as in neon matrix have shown that this reaction proceed via a hydrogen abstraction, leading to the formation of NH2 radical, that further recombine with hydroxyl radical to form hydroxylamine, under non-energetic conditions.

Transcriptional analysis of the multicopy hao gene coding for hydroxylamine oxidoreductase in Nitrosomonas sp. strain ENI-11.

PubMed

Hirota, Ryuichi; Kuroda, Akio; Ikeda, Tsukasa; Takiguchi, Noboru; Ohtake, Hisao; Kato, Junichi

2006-08-01

The nitrifying bacterium Nitrosomonas sp. strain ENI-11 has three copies of the gene encoding hydroxylamine oxidoreductase (hao(1), hao(2), and hao(3)) on its genome. Broad-host-range reporter plasmids containing transcriptional fusion genes between hao copies and lacZ were constructed to analyze the expression of each hydroxylamine oxidoreductase gene (hao) copy individually and quantitatively. beta-Galactosidase assays of ENI-11 harboring reporter plasmids revealed that all hao copies were transcribed in the wild-type strain. Promoter analysis of hao copies revealed that transcription of hao(3) was highest among the hao copies. Expression levels of hao(1) and hao(2) were 40% and 62% of that of hao(3) respectively. Transcription of hao(1) was negatively regulated, whereas a portion of hao(3) transcription was read through transcription from the rpsT promoter. When energy-depleted cells were incubated in the growth medium, only hao(3) expression increased. This result suggests that it is hao(3) that is responsible for recovery from energy-depleted conditions in Nitrosomonas sp. strain ENI-11.

Visible-light-promoted and one-pot synthesis of phenanthridines and quinolines from aldehydes and O-acyl hydroxylamine.

PubMed

An, Xiao-De; Yu, Shouyun

2015-06-05

A one-pot synthesis of phenanthridines and quinolines from commercially available or easily prepared aldehydes has been reported. O-(4-Cyanobenzoyl)hydroxylamine was utilized as the nitrogen source to generate O-acyl oximes in situ with aldehydes catalyzed by Brønsted acid. O-Acyl oximes were then subjected to visible light photoredox catalyzed cyclization via iminyl radicals to furnish aza-arenes. A variety of phenanthridines and quinolines have been prepared assisted by Brønsted acid and photocatalyst under visible light at room temperature with satisfactory yields.

Mutational analysis of the multicopy hao gene coding for hydroxylamine oxidoreductase in Nitrosomonas sp. strain ENI-11.

PubMed

Yamagata, A; Hirota, R; Kato, J; Kuroda, A; Ikeda, T; Takiguchi, N; Ohtake, H

2000-08-01

The ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11 contains three copies of the hao gene (hao1, hao2, and hao3) coding for hydroxylamine oxidoreductase (HAO). Three single mutants (hao1::kan, hao2::kan, or hao3::kan) had 68 to 75% of the wild-type growth rate and 58 to 89% of the wild-type HAO activity when grown under the same conditions. A double mutant (hao1::kan and hao3::amp) also had 68% of the wild-type growth and 37% of the wild-type HAO activity.

The inhibitory effect of 3-amino-1,2,4-triazole on relaxation induced by hydroxylamine and sodium azide but not hydrogen peroxide or glyceryl trinitrate in rat aorta.

PubMed Central

Mian, K. B.; Martin, W.

1995-01-01

1. In this study we investigated the role of catalase in relaxation induced by hydroxylamine, sodium azide, glyceryl trinitrate and hydrogen peroxide in isolated rings of rat aorta. 2. Hydrogen peroxide (1 microM-1 mM)-induced concentration-dependent relaxation of phenylephrine (PE)-induced tone in endothelium-containing rings. In endothelium-denuded rings, however, higher concentrations (30 microM-1 mM) of hydrogen peroxide were required to produce relaxation. The endothelium-dependent component of hydrogen peroxide-induced relaxation was abolished following pretreatment with N(O)-nitro-L-arginine methyl ester (L-NAME, 30 microM). L-NAME (30 microM) had no effect, however, on hydrogen peroxide-induced relaxation in endothelium-denuded rings. 3. Pretreatment of endothelium-denuded rings with catalase (1000 u ml-1) blocked relaxation induced by hydrogen peroxide (10 microM-1 mM). The ability of catalase to inhibit hydrogen peroxide-induced relaxation was partially blocked following incubation with 3-amino-1,2, 4-triazole (AT, 50 mM) for 30 min and completely blocked at 90 min. 4. Pretreatment of endothelium-denuded rings with methylene blue (MeB, 30 microM) inhibited relaxation induced by hydrogen peroxide (10 microM-1 mM), sodium azide (1-300 nM), hydroxylamine (1-300 nM) and glyceryl trinitrate (1-100 nM) suggesting that each acted by stimulation of soluble guanylate cyclase. 5. Pretreatment of endothelium-denuded rings with AT (1-50 mM, 90 min) to inhibit endogenous catalase blocked relaxation induced by sodium azide (1-300 nM) and hydroxylamine (1-300 nM) but had no effect on relaxation induced by hydrogen peroxide (10 microM-1 mM) or glyceryl trinitrate (1-100 nM). 6. In a cell-free system, incubation of sodium azide (10 microM-3 mM) and hydroxylamine (10 microM-30 mM) but not glyceryl trinitrate (10 microM-1 mM) with catalase (1000 u ml-1) in the presence of hydrogen peroxide (1 mM) led to production of nitrite, a major breakdown product of nitric oxide. AT (1-100 mM) inhibited, in a concentration-dependent manner, the formation of nitrite from azide in the presence of hydrogen peroxide. 7. These data suggest that metabolism by catalase plays an important role in the relaxation induced by hydroxylamine and sodium azide in isolated rings of rat aorta. Relaxation appears to be due to formation of nitric oxide and activation of soluble guanylate cyclase. In contrast, metabolism by catalase does not appear to be involved in the relaxant actions of hydrogen peroxide or glyceryl trinitrate. PMID:8719811

Redox equilibria in hydroxylamine oxidoreductase. Electrostatic control of electron redistribution in multielectron oxidative processes.

PubMed

Kurnikov, Igor V; Ratner, Mark A; Pacheco, A Andrew

2005-02-15

We report results of continuum electrostatics calculations of the cofactor redox potentials, and of the titratable group pK(a) values, in hydroxylamine oxidoreductase (HAO). A picture of a sophisticated multicomponent control of electron flow in the protein emerged from the studies. First, we found that neighboring heme cofactors strongly interact electrostatically, with energies of 50-100 mV. Thus, cofactor redox potentials depend on the oxidation state of other cofactors, and cofactor redox potentials in the active (partially oxidized) enzyme differ substantially from the values obtained in electrochemical redox titration experiments. We found that, together, solvent-exposed heme 1 (having a large negative redox potential) and heme 2 (having a large positive redox potential) form a lock for electrons generated during the oxidation reaction The attachment of HAO's physiological electron transfer partner cytochrome c(554) results in a positive shift in the redox potential of heme 1, and "opens the electron gate". Electrons generated as a result of hydroxylamine oxidation travel to heme 3 and heme 8, which have redox potentials close to 0 mV versus NHE (this result is in partial disagreement with an existing experimental redox potential assignment). The closeness of hemes 3 and 8 from different enzyme subunits allows redistribution of the four electrons generated as a result of hydroxylamine oxidation, among the three enzyme subunits. For the multielectron oxidation process to be maximally efficient, the redox potentials of the electron-accepting cofactors should be roughly equal, and electrostatic interactions between extra electrons on these cofactors should be minimal. The redox potential assignments presented in the paper satisfy this general rule.

Reaction of carnosine with aged proteins: another protective process?

PubMed

Hipkiss, Alan R; Brownson, Carol; Bertani, Mariana F; Ruiz, Emilio; Ferro, Albert

2002-04-01

Cellular aging is often associated with an increase in protein carbonyl groups arising from oxidation- and glycation-related phenomena and suppressed proteasome activity. These "aged" polypeptides may either be degraded by 20S proteasomes or cross-link to form structures intractable to proteolysis and inhibitory to proteasome activity. Carnosine (beta-alanyl-l-histidine) is present at surprisingly high levels (up to 20 mM) in muscle and nervous tissues in many animals, especially long-lived species. Carnosine can delay senescence in cultured human fibroblasts and reverse the senescent phenotype, restoring a more juvenile appearance. As better antioxidants/free-radical scavengers than carnosine do not demonstrate these antisenescent effects, additional properties of carnosine must contribute to its antisenescent activity. Having shown that carnosine can react with protein carbonyls, thereby generating "carnosinylated" polypeptides using model systems, we propose that similar adducts are generated in senescent cells exposed to carnosine. Polypeptide-carnosine adducts have been recently detected in beef products that are relatively rich in carnosine, and carnosine's reaction with carbonyl functions generated during amino acid deamidation has also been described. Growth of cultured human fibroblasts with carnosine stimulated proteolysis of long-labeled proteins as the cells approached their "Hayflick limit," consistent with the idea that carnosine ameliorates the senescence-associated proteolytic decline. We also find that carnosine suppresses induction of heme-oxygenase-1 activity following exposure of human endothelial cells to a glycated protein. The antisenescent activity of the spin-trap agent alpha-phenyl-N-t-butylnitrone (PBN) towards cultured human fibroblasts resides in N-t-butyl-hydroxylamine, its hydrolysis product. As hydroxylamines are reactive towards aldehydes and ketones, the antisenescent activity of N-t-butyl-hydroxylamine and other hydroxylamines may be mediated, at least in part, by reactivity towards macromolecular carbonyls, analogous to that proposed for carnosine.

Reduction of aromatic and heterocyclic aromatic N-hydroxylamines by human cytochrome P450 2S1.

PubMed

Wang, Kai; Guengerich, F Peter

2013-06-17

Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals, and there is also strong evidence of some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anticancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions [Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740-1751]. In the study presented here, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs.

Reduction of Aromatic and Heterocyclic Aromatic N-Hydroxylamines by Human Cytochrome P450 2S1

PubMed Central

Wang, Kai; Guengerich, F. Peter

2013-01-01

Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals and there is also strong evidence for some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anti-cancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions (Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740–1751). In the present study, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs. PMID:23682735

Metabolism of 4-Chloronitrobenzene by the Yeast Rhodosporidium sp

PubMed Central

Corbett, Michael D.; Corbett, Bernadette R.

1981-01-01

The yeast Rhodosporidium sp. metabolized 4-chloronitrobenzene by a reductive pathway to give 4-chloroacetanilide and 4-chloro-2-hydroxyacetanilide as the major final metabolites. The intermediate production of 4-chloronitrosobenzene, 4-chlorophenylhydroxylamine, and 4-chloroaniline was demonstrated by high-pressure liquid chromatography. Additional studies with selected metabolites established that the metabolite 4-chloro-2-hydroxyacetanilide was produced by an initial Bamberger rearrangement of the hydroxylamine metabolite, followed by acetylation. Direct C hydroxylation of the aromatic ring was not observed in this species. No hydroxamic acid production was detected, even though significant concentrations of the nitroso and hydroxylamine precursors to this functional group were observed. PMID:16345757

N-O linkage in carbohydrates and glycoconjugates.

PubMed

Chen, N; Xie, J

2016-11-29

The importance of oligosaccharides and their conjugates in various biological and pathological processes has stimulated growing interest in the development of (neo)glycoconjugates. Thanks to its high nucleophilicity, hydroxylamine has been employed as a powerful chemoselective ligation tool. Great effort has been focused on carbohydrates bearing aminooxy or N-hydroxy amino groups for organic synthesis, glycobiology and drug discovery. This review provides an overview of N-O linked carbohydrates and glycoconjugates, focusing particularly on the synthetic methodologies and chemical and physicochemical properties as well as biological and medical applications of N-glycosyl and O-glycosyl hydroxylamines, N-hydroxy amino and O-amino sugar as well as sugar aminooxy acid derivatives.

Highly Efficient Release of Glycopeptides from Hydrazide Beads by Hydroxylamine Assisted PNGase F Deglycosylation for N-Glycoproteome Analysis.

PubMed

Huang, Junfeng; Wan, Hao; Yao, Yating; Li, Jinan; Cheng, Kai; Mao, Jiawei; Chen, Jin; Wang, Yan; Qin, Hongqiang; Zhang, Weibing; Ye, Mingliang; Zou, Hanfa

2015-10-20

Selective enrichment of glycopeptides from complex sample followed by cleavage of N-glycans by PNGase F to expose an easily detectable mark on the former glycosylation sites has become the popular protocol for comprehensive glycoproteome analysis. On account of the high enrichment specificity, hydrazide chemistry based solid-phase extraction of N-linked glycopeptides technique has sparked numerous interests. However, the enzymatic release of glycopeptides captured by hydrazide beads through direct incubation of the beads with PNGase F is not efficient due to the inherent steric hindrance effect. In this study, we developed a hydroxylamine assisted PNGase F deglycosylation (HAPD) method using the hydroxylamine to release glycopeptides captured on the hydrazide beads through the cleavage of hydrazone bonds by transamination followed with the PNGase F deglycosylation of the released glycopeptides in the free solution. Because of the homogeneous condition for the deglycosylation, the recovery of deglycosylated peptides (deglycopeptides) was improved significantly. It was found that 27% more N-glycosylation sites were identified by the HAPD strategy compared with the conventional method. Moreover, the ratio of identified N-terminal glycosylated peptides was improved over 5-fold.

Kinetic properties of wild-type and altered recombinant amidases by the use of ion-selective electrode assay method.

PubMed

Martins, S; Karmali, A; Serralheiro, M L

2006-08-15

A novel assay method was investigated for wild-type and recombinant mutant amidases (EC 3.5.1.4) from Pseudomonas aeruginosa by ammonium ion-selective electrode (ISE). The initial velocity is proportional to the enzyme concentration by using the wild-type enzyme. The specific activities of the purified amidase were found to be 88.2 and 104.2 U mg protein(-1) for the linked assay and ISE methods, respectively. The kinetic constants--Vmax, Km, and Kcat--determined by Michaelis-Menten plot were 101.13 U mg protein(-1), 1.12x10(-2) M, and 64.04 s(-1), respectively, for acrylamide as the substrate. On the other hand, the lower limit of detection and range of linearity of enzyme concentration were found to be 10.8 and 10.8 to 500 ng, respectively, for the linked assay method and 15.0 and 15.0 to 15,000 ng, respectively, for the ISE method. Hydroxylamine was found to act as an uncompetitive activator of hydrolysis reaction catalyzed by amidase given that there is an increase in Vmax and Km when acetamide was used as the substrate. However, the effect of hydroxylamine on the hydrolysis reaction was dependent on the type of amidase and substrate involved in the reaction mixture. The degrees of activation (epsilon(a)) of the wild-type and mutant (T103I and C91A) enzymes were found to be 2.54, 12.63, and 4.33, respectively, for acetamide as the substrate. However, hydroxylamine did not activate the reaction catalyzed by wild-type and altered (C91A and W138G) amidases by using acrylamide and acetamide, respectively, as the substrate. The activating effect of hydroxylamine on the hydrolysis of acetamide, acrylamide, and p-nitrophenylacetamide can be explained by the fact that additional formation of ammonium ions occurred due to the transferase activity of amidases. However, the activating effect of hydroxylamine on the hydrolysis of p-nitroacetanilide may be due to a change in conformation of enzyme molecule. Therefore, the use of ISE permitted the study of the kinetic properties of wild-type and mutant amidases because it was possible to measure initial velocity of the enzyme-catalyzed reaction in real time.

Production of superoxide in chloroplast thylakoid membranes ESR study with cyclic hydroxylamines of different lipophilicity.

PubMed

Kozuleva, Marina; Klenina, Irina; Proskuryakov, Ivan; Kirilyuk, Igor; Ivanov, Boris

2011-04-06

Accumulation of nitroxide radicals, DCP· or TMT·, under illumination of a thylakoid suspension containing either hydrophilic, DCP-H, or lipophilic, TMT-H, cyclic hydroxylamines that have high rate constants of the reaction with superoxide radicals, was measured using ESR. A slower accumulation of TMT· in contrast with DCP· accumulation was explained by re-reduction of TMT· by the carriers of the photosynthetic electron transport chain within the membrane. Superoxide dismutase suppressed TMT· accumulation to a lesser extent than DCP· accumulation. The data are interpreted as evidencing the production of intramembrane superoxide in thylakoids. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Detection of single base mismatches of thymine and cytosine residues by potassium permanganate and hydroxylamine in the presence of tetralkylammonium salts.

PubMed Central

Gogos, J A; Karayiorgou, M; Aburatani, H; Kafatos, F C

1990-01-01

In the presence of tetramethylammonium chloride, potassium permanganate specifically modifies mismatched thymines. Similarly, the modification of mismatched cytosines by hydroxylamine was enhanced by tetraethylammonium chloride. Modification followed by piperidine cleavage permits specific identification of the T and C mismatches and by extension, when the opposite DNA strand is analyzed, of A and G mismatches as well. These reactions can be performed conveniently with DNA immobilized on Hybond M-G paper. We describe conditions that exploit these reactions to detect mismatches, e.g. point mutations or genetic polymorphisms, using either synthetic oligonucleotide probes or PCR amplification of specific genomic DNA sequences. Images PMID:2263445

Hydroxylamine hydrochloride-acetic acid-soluble and -insoluble fractions of pelagic sediment: Readsorption revisited

USGS Publications Warehouse

Piper, D.Z.; Wandless, G.A.

1992-01-01

The extraction of the rare earth elements (REE) from deep-ocean pelagic sediment, using hydroxylamine hydrochloride-acetic acid, leads to the separation of approximately 70% of the bulk REE content into the soluble fraction and 30% into the insoluble fraction. The REE pattern of the soluble fraction, i.e., the content of REE normalized to average shale on an element-by-element basis and plotted against atomic number, resembles the pattern for seawater, whereas the pattern, as well as the absolute concentrations, in the insoluble fraction resembles the North American shale composite. These results preclude significant readsorption of the REE by the insoluble phases during the leaching procedure.

Glycine and alanine synthesis from formaldehyde and hydroxylamine in the field of ultrasound waves.

PubMed

Sokolskaya, A

1976-08-01

High intensity ultrasound waves coupled with other form of energy obviously were initiators of pre-biochemical reactions; these reactions occurred in the water masses of the primordial Earth. Essential biological substances like formaldehyde, ammonia, hydrocyanic acid, and amino acids compounds similar to carbohydrates by their properties were synthesized in the field of ultrasound waves in model experiments. The main partners of these reactions are water and gases of reductional atomosphere: hydrogen, carbon monoxide, methane, nitrogen and argon. Formation of amino acids takes place in aqueous solutions of formaldehyde and hydroxylamine. The sonication yielded alanine and glycine, 2.0 X 10(-7) and 1.8 X 10(-7) molecules per 100 eV respectively.

Hydroxylamine derivatives for regulation of spermine and spermidine metabolism.

PubMed

Khomutov, M A; Weisell, J; Hyvönen, M; Keinänen, T A; Vepsäläinen, J; Alhonen, L; Khomutov, A R; Kochetkov, S N

2013-12-01

The biogenic polyamines spermine, spermidine, and their precursor putrescine are present in micro-to-millimolar concentrations in all cell types and are vitally important for their normal growth. High intracellular content of spermine and spermidine determines the multiplicity of the cellular functions of the polyamines. Many of these functions are not well characterized at the molecular level, ensuring the ongoing development of this field of biochemistry. Tumor cells have elevated polyamine level if compared with normal cells, and this greatly stimulates the search for new opportunities to deplete the intracellular pool of spermine and spermidine resulting in decrease in cell growth and even cell death. O-Substituted hydroxylamines occupy their own place among chemical regulators of the activity of the enzymes of polyamine metabolism. Varying the structure of the alkyl substituent made it possible to obtain within one class of chemical compounds highly effective inhibitors and regulators of the activity of all the enzymes of putrescine, spermine and spermidine metabolism (with the exception of FAD-dependent spermine oxidase and acetylpolyamine oxidase), effectors of the polyamine transport system, and even actively transported in cells "proinhibitor" of ornithine decarboxylase. Some principles for the design of specific inhibitors of these enzymes as well as the peculiarities of cellular effects of corresponding O-substituted hydroxylamines are discussed.

Reduction of nitric oxide catalyzed by hydroxylamine oxidoreductase from an anammox bacterium.

PubMed

Irisa, Tatsuya; Hira, Daisuke; Furukawa, Kenji; Fujii, Takao

2014-12-01

The hydroxylamine oxidoreductase (HAO) from the anammox bacterium, Candidatus Kuenenia stuttgartiensis has been reported to catalyze the oxidation of hydroxylamine (NH2OH) to nitric oxide (NO) by using bovine cytochrome c as an oxidant. In contrast, we investigated whether the HAO from anammox bacterium strain KSU-1 could catalyze the reduction of NO with reduced benzyl viologen (BVred) and the NO-releasing reagent, NOC 7. The reduction proceeded, resulting in the formation of NH2OH as a product. The oxidation rate of BVred was proportional to the concentration of BVred itself for a short period in each experiment, a situation that was termed quasi-steady state. The analyses of the states at various concentrations of HAO allowed us to determine the rate constant for the catalytic reaction, (2.85 ± 0.19) × 10(5) M(-1) s(-1), governing NO reduction by BVred and HAO, which was comparable to that reported for the HAO from the ammonium oxidizer, Nitrosomonas with reduced methyl viologen. These results suggest that the anammox HAO functions to adjust anammox by inter-conversion of NO and NH2OH depending on the redox potential of the physiological electron transfer protein in anammox bacteria. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Heterotrophic nitrogen removal in Bacillus sp. K5: involvement of a novel hydroxylamine oxidase.

PubMed

Yang, Yunlong; Lin, Ershu; Huang, Shaobin

2017-12-01

An aerobic denitrifying bacterium isolated from a bio-trickling filter treating NOx, Bacillus sp. K5, is able to convert ammonium to nitrite, in which hydroxylamine oxidase (HAO) plays a critical role. In the present study, the performance for simultaneous nitrification and denitrification was investigated with batch experiments and an HAO was purified by an anion-exchange and gel-filtration chromatography from strain K5. The purified HAO's molecular mass was determined by SDS-PAGE and its activity by measuring the change in the concentration of ferricyanide, the electron acceptor. Results showed that as much as 87.8 mg L -1 ammonium-N was removed without nitrite accumulation within 24 hours in the sodium citrate medium at C/N of 15. The HAO isolated from the strain K5 was approximately 71 KDa. With hydroxylamine (NH 2 OH) as a substrate and potassium ferricyanide as an electron acceptor, the enzyme was capable of oxidizing NH 2 OH to nitrite in vitro when the pH varied from 7 to 9 and temperature ranged from 25 °C to 40 °C. This is the first time that an HAO has been purified from the Bacillus genus, and the findings revealed that it is distinctive in its molecular mass and enzyme properties.

Phase I and phase II reductive metabolism simulation of nitro aromatic xenobiotics with electrochemistry coupled with high resolution mass spectrometry.

PubMed

Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Ke; Li, Weiming

2014-11-01

Electrochemistry combined with (liquid chromatography) high resolution mass spectrometry was used to simulate the general reductive metabolism of three biologically important nitro aromatic molecules: 3-trifluoromethyl-4-nitrophenol (TFM), niclosamide, and nilutamide. TFM is a pesticide used in the Laurential Great Lakes while niclosamide and nilutamide are used in cancer therapy. At first, a flow-through electrochemical cell was directly connected to a high resolution mass spectrometer to evaluate the ability of electrochemistry to produce the main reduction metabolites of nitro aromatic, nitroso, hydroxylamine, and amine functional groups. Electrochemical experiments were then carried out at a constant potential of -2.5 V before analysis of the reduction products by LC-HRMS, which confirmed the presence of the nitroso, hydroxylamine, and amine species as well as dimers. Dimer identification illustrates the reactivity of the nitroso species with amine and hydroxylamine species. To investigate xenobiotic metabolism, the reactivity of nitroso species to biomolecules was also examined. Binding of the nitroso metabolite to glutathione was demonstrated by the observation of adducts by LC-ESI(+)-HRMS and the characteristics of their MSMS fragmentation. In conclusion, electrochemistry produces the main reductive metabolites of nitro aromatics and supports the observation of nitroso reactivity through dimer or glutathione adduct formation.

Catalytic effects of silver plasmonic nanoparticles on the redox reaction leading to ABTS˙+ formation studied using UV-visible and Raman spectroscopy.

PubMed

Garcia-Leis, A; Jancura, D; Antalik, M; Garcia-Ramos, J V; Sanchez-Cortes, S; Jurasekova, Z

2016-09-29

ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) is a compound extensively employed to evaluate the free radical trapping capacity of antioxidant agents and complex mixtures such as biological fluids or foods. This evaluation is usually performed by using a colourimetric experiment, where preformed ABTS radical cation (ABTS˙ + ) molecules are reduced in the presence of an antioxidant causing an intensity decrease of the specific ABTS˙ + UV-visible absorption bands. In this work we report a strong effect of silver plasmonic nanoparticles (Ag NPs) on ABTS leading to the formation of ABTS˙ + . The reaction of ABTS with Ag NPs has been found to be dependent on the interfacial and plasmonic properties of NPs. Specifically, this reaction is pronounced in the presence of spherical nanoparticles prepared by the reduction of silver nitrate with hydroxylamine (AgH) and in the case of star-shaped silver nanoparticles (AgNS). On the other hand, spherical nanoparticles prepared by the reduction of silver nitrate with citrate apparently do not react with ABTS. Additionally, the formation of ABTS˙ + is investigated by surface-enhanced Raman scattering (SERS) and the assignment of the most intense vibrational bands of this compound is performed. The SERS technique enables us to detect this radical cation at very low concentrations of ABTS (∼2 μM). Altogether, these findings allow us to suggest the use of ABTS/Ag NPs-systems as reliable and easy going substrates to test the antioxidant capacity of various compounds, even at concentrations much lower than those usually used in the spectrophotometric assays. Moreover, we have suggested that ABTS could be employed as a suitable agent to investigate the interfacial and plasmonic properties of the metal nanoparticles and, thus, to characterize the nanoparticle metal systems employed for various purposes.

Identification of succinimide sites in proteins by N-terminal sequence analysis after alkaline hydroxylamine cleavage.

PubMed Central

Kwong, M. Y.; Harris, R. J.

1994-01-01

Under favorable conditions, Asp or Asn residues can undergo rearrangement to a succinimide (cyclic imide), which may also serve as an intermediate for deamidation and/or isoaspartate formation. Direct identification of such succinimides by peptide mapping is hampered by their lability at neutral and alkaline pH. We determined that incubation in 2 M hydroxylamine, 0.2 M Tris buffer, pH 9, for 2 h at 45 degrees C will specifically cleave on the C-terminal side of succinimides without cleavage at Asn-Gly bonds; yields are typically approximately 50%. N-terminal sequence analysis can then be used to identify an internal sequence generated by cleavage of the succinimide, hence identifying the succinimide site. PMID:8142891

Plant cells oxidize hydroxylamines to NO

PubMed Central

Rümer, Stefan; Gupta, Kapuganti Jagadis; Kaiser, Werner M.

2009-01-01

Plants are known to produce NO via the reduction of nitrite. Oxidative NO production in plants has been considered only with respect to a nitric oxide synthase (NOS). Here it is shown that tobacco cell suspensions emitted NO when hydroxylamine (HA) or salicylhydroxamate (SHAM), a frequently used AOX inhibitor, was added. NG-hydroxy-L-arginine, a putative intermediate in the NOS-reaction, gave no NO emission. Only a minor fraction (≤1%) of the added HA or SHAM was emitted as NO. Production of NO was decreased by anoxia or by the addition of catalase, but was increased by conditions inducing reactive oxygen (ROS) or by the addition of hydrogen peroxide. Cell-free enzyme solutions generating superoxide or hydrogen peroxide also led to the formation of NO from HA or (with lower rates) from SHAM, and nitrite was also an oxidation product. Unexpectedly, the addition of superoxide dismutase (SOD) to cell suspensions stimulated NO formation from hydroxylamines, and SOD alone (without cells) also catalysed the production of NO from HA or SHAM. NO production by SOD plus HA was higher in nitrogen than in air, but from SOD plus SHAM it was lower in nitrogen. Thus, SOD-catalysed NO formation from SHAM and from HA may involve different mechanisms. While our data open a new possibility for oxidative NO formation in plants, the existence and role of these reactions under physiological conditions is not yet clear. PMID:19357430

Vicarious nucleophilic substitution using 4-amino-1,2,4-triazole, hydroxylamine or O-alkylhydroxylamine to prepare 1,3-diamino-2,4,6-trinitrobenzene or 1,3,5-triamino-2,4,6-trinitrobenzene

DOEpatents

Mitchell, A.R.; Pagoria, P.F.; Schmidt, R.D.

1997-05-27

The present invention relates to a process to produce 1,3-diamino-2,4,6-trinitrobenzene (DATB) or 1,3,5-triamino-2,4,6,trinitrobenzene (TATB) by: (a) reacting at ambient pressure and a temperature of between about 0 and 50 C for between about 0.1 and 24 hr, a trinitroaromatic compound of the structure shown where X, Y, and Z are each independently selected from the group consisting of -H and -NH{sub 2}, with the proviso that at least 1 or 2 of X, Y, and Z are hydrogen; with an effective amount of 1-amino-1,2,4-triazole, hydroxylamine or O-alkylhydroxamine to produce DATB or TATB; in the presence of a strong base selected from sodium butoxide, potassium butoxide, potassium propoxide, sodium propoxide, sodium ethoxide, potassium ethoxide, sodium methoxide, potassium methoxide, and combinations thereof; in a solvent selected from the group consisting of methanol, ethanol, propanol, butanol, dimethylsulphoxide, N-methylpyrrolidone, hexamethylphosphoramide, dimethylformide, dimethylacetamide and mixtures thereof, provided that when alcohols are present or when hydroxylamine or its O-alkyl derivatives replace ATA primarily DATB is formed; and (b) isolating the DATB or TATB produced. DATB and TATB are important and useful specialty explosives and intermediates for other materials.

Vicarious nucleophilic substitution using 4-amino-1,2,4-triazole, hydroxylamine or O-alkylhydroxylamine to prepare 1,3-diamino-2,4,6-trinitrobenzene or 1,3,5-triamino-2,4,6-trinitrobenzene

DOEpatents

Mitchell, Alexander R.; Pagoria, Philip F.; Schmidt, Robert D.

1997-01-01

The present invention relates to a process to produce 1,3-diamino-2,4,6-trinitrobenzene (DATB) or 1,3,5-triamino-2,4,6,-trinitrobenzene (TATB) by: (a) reacting at ambient pressure and a temperature of between about 0.degree. and 50.degree. C. for between about 0.1 and 24 hr, a trinitroaromatic compound of structure V: ##STR1## wherein X, Y, and Z are each independently selected from the group consisting of --H and --NH.sub.2, with the proviso that at least 1 or 2 of X, Y, and Z are hydrogen; with an effective amount of 1-amino-1,2,4-triazole, hydroxylamine or O-alkylhydroxamine to produce DATB or TATB; in the presence of a strong base selected from sodium butoxide, potassium butoxide, potassium propoxide, sodium propoxide, sodium ethoxide, potassium ethoxide, sodium methoxide, potassium methoxide, and combinations thereof; in a solvent selected from the group consisting of methanol, ethanol, propanol, butanol, dimethylsulphoxide, N-methylpyrrolidone, hexamethylphosphoramide, dimethylformide, dimethylacetamide and mixtures thereof, provided that when alcohols are present or when hydroxylamine or its O-alkyl derivatives replace ATA primarily DATB is formed; and (b) isolating the DATB or TATB produced. DATB and TATB are important and useful specialty explosives and intermediates for other materials.

Chemical Synthesis of the 20 kDa Heme Protein Nitrophorin 4 by α-Ketoacid-Hydroxylamine (KAHA) Ligation.

PubMed

He, Chunmao; Kulkarni, Sameer S; Thuaud, Frédéric; Bode, Jeffrey W

2015-10-26

The chemical synthesis of the 184-residue ferric heme-binding protein nitrophorin 4 was accomplished by sequential couplings of five unprotected peptide segments using α-ketoacid-hydroxylamine (KAHA) ligation reactions. The fully assembled protein was folded to its native structure and coordinated to the ferric heme b cofactor. The synthetic holoprotein, despite four homoserine residues at the ligation sites, showed identical properties to the wild-type protein in nitric oxide binding and nitrite dismutase reactivity. This work establishes the KAHA ligation as a valuable and viable approach for the chemical synthesis of proteins up to 20 kDa and demonstrates that it is well-suited for the preparation of hydrophobic protein targets. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Can hydroxylamine be a more potent nucleophile for the reactivation of tabun-inhibited AChE than prototype oxime drugs? An answer derived from quantum chemical and steered molecular dynamics studies.

PubMed

Lo, Rabindranath; Ganguly, Bishwajit

2014-07-29

Organophosphorus nerve agents are highly toxic compounds which strongly inhibit acetylcholinesterase (AChE) in the blood and in the central nervous system (CNS). Tabun is one of the highly toxic organophosphorus (OP) compounds and is resistant to many oxime drugs formulated for the reactivation of AChE. The reactivation mechanism of tabun-conjugated AChE with various drugs has been examined with density functional theory and ab initio quantum chemical calculations. The presence of a lone-pair located on the amidic group resists the nucleophilic attack at the phosphorus center of the tabun-conjugated AChE. We have shown that the newly designed drug candidate N-(pyridin-2-yl)hydroxylamine, at the MP2/6-31+G*//M05-2X/6-31G* level in the aqueous phase with the polarizable continuum solvation model (PCM), is more effective in reactivating the tabun-conjugated AChE than typical oxime drugs. The rate determining activation barrier with N-(pyridin-2-yl)hydroxylamine was found to be ∼1.7 kcal mol(-1), which is 7.2 kcal mol(-1) lower than the charged oxime trimedoxime (one of the most efficient reactivators in tabun poisonings). The greater nucleophilicity index (ω(-)) and higher CHelpG charge of pyridinylhydroxylamine compared to TMB4 support this observation. Furthermore, we have also examined the reactivation process of tabun-inhibited AChE with some other bis-quaternary oxime drug candidates such as methoxime (MMB4) and obidoxime. The docking analysis suggests that charged bis-quaternary pyridinium oximes have greater binding affinity inside the active-site gorge of AChE compared to the neutral pyridinylhydroxylamine. The peripheral ligand attached to the neutral pyridinylhydroxylamine enhanced the binding with the aromatic residues in the active-site gorge of AChE through effective π-π interactions. Steered molecular dynamics (SMD) simulations have also been performed with the charged oxime (TMB4) and the neutral hydroxylamine. From protein-drug interaction parameters (rupture force profiles, hydrogen bonds, hydrophobic interactions), geometry and the orientation of the drug candidates, the hydroxylamine is suggested to orchestrate the reactivation process better than TMB4. Furthermore, the calculated log P values show the effective penetration of the neutral drug candidate through the blood-brain barrier. The toxicity measurements and the IC50 values (a measure of the intrinsic affinity toward AChE) suggest that the pyridinylhydroxylamine compound could have similar toxic behavior compared to the prototype oxime antidotes used for reactivation purposes. The newly designed pyridinylhydroxylamine drug candidate can be an effective antidote both kinetically and structurally to reactivate the tabun-inhibited enzyme.

Coupled effects of methane monooxygenase and nitrogen source on growth and poly-β-hydroxybutyrate (PHB) production of Methylosinus trichosporium OB3b.

PubMed

Zhang, Tingting; Zhou, Jiti; Wang, Xiaowei; Zhang, Yu

2017-02-01

The coupled effects of nitrogen source and methane monooxygenase (MMO) on the growth and poly-β-hydroxybutyrate (PHB) accumulation capacity of methanotrophs were explored. The ammonia-supplied methanotrophs expressing soluble MMO (sMMO) grew at the highest rate, while N 2 -fixing bacteria expressing particulate MMO (pMMO) grew at the lowest rate. Further study showed that more hydroxylamine and nitrite was formed by ammonia-supplied bacteria containing pMMO, which might cause their slightly lower growth rate. The highest PHB content (51.0%) was obtained under nitrogen-limiting conditions with the inoculation of nitrate-supplied bacteria containing pMMO. Ammonia-supplied bacteria also accumulated a higher content of PHB (45.2%) with the expression of pMMO, while N 2 -fixing bacteria containing pMMO only showed low PHB production capacity (32.1%). The maximal PHB contents of bacteria expressing sMMO were low, with no significant change under different nitrogen source conditions. The low MMO activity, low cell growth rate and low PHB production capacity of methanotrophs continuously cultivated with N 2 with the expression of pMMO were greatly improved in the cyclic NO 3 - N 2 cultivation regime, indicating that long-term deficiency of nitrogen sources was detrimental to the activity of methanotrophs expressing pMMO. Copyright © 2016. Published by Elsevier B.V.

Synthesis of hetero annulated isoxazolo-, pyrido- and pyrimido carbazoles: Screened for in vitro antitumor activity and structure activity relationships, a novel 2-amino-4-(3'-bromo-4'-methoxyphenyl)-8-chloro-11H-pyrimido[4,5-a]carbazole as an antitumor agent.

PubMed

Murali, Karunanidhi; Sparkes, Hazel A; Rajendra Prasad, Karnam Jayarampillai

2017-03-10

Claisen-Schmidt condensation of 2,3,4,9-tetrahydro-1H-carbazol-1-one with 3-bromo-4-methoxy benzaldehyde afforded the 2-(3'-bromo-4'-methoxybenzylidene)-2,3,4,9-tetrahydro-1H-carbazol-1-one 3. Compound 3 was allowed to react with different organic reactants, hydroxylamine hydrochloride, malononitrile and guanidine nitrate through condensation cum cycloaddition reactions to afford a series of the respective novel hetero annulated carbazoles such as isoxazolo-, pyrido- and pyrimido carbazoles. The structures of the compounds were established by FT-IR, 1 H NMR, 13 C NMR, X-ray diffraction and elemental analysis. The compounds have been screened for in vitro anti-tumor activity by MTT assay and displayed enviable selective growth inhibition on MCF-7 cell line compared to A-549 cell line. Apoptotic morphological changes in MCF-7 and A-549 cells were visualized using fluorescent microscopic technique. The preliminary structure activity relationships were also carried out. Data pointed out that among pyrimido carbazole compounds, 2-amino-4-(3'-bromo-4'-methoxyphenyl)-8-chloro-11H-pyrimido [4,5-a]carbazole could be exploited as an excellent therapeutic drug against cancer cell proliferation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Chemical synthesis of a homoserine-mutant of the antibacterial, head-to-tail cyclized protein AS-48 by α-ketoacid–hydroxylamine (KAHA) ligation† †Electronic supplementary information (ESI) available: Experimental procedures, supplementary results, and spectroscopic data for new compounds. See DOI: 10.1039/c7sc00789b Click here for additional data file.

PubMed Central

Rohrbacher, Florian; Zwicky, André

2017-01-01

An antibacterial cyclic AS-48 protein was chemically synthesized by α-ketoacid–hydroxylamine (KAHA) ligation. Initial challenges associated with the exceptionally hydrophobic segments arising from the amphiphilic nature of the protein were resolved by the development of bespoke reaction conditions for hydrophobic segments, using hexafluoroisopropanol (HFIP) as a co-solvent. The synthetic protein displays similar biological activity and properties to those of the native protein. To support the current understanding of its antibacterial mode of action, we demonstrate the ability of AS-48 to be incorporated into synthetic multilamellar vesicles (MLVs). PMID:28580120

Measurement of Nonribosomal Peptide Synthetase Adenylation Domain Activity Using a Continuous Hydroxylamine Release Assay.

PubMed

Duckworth, Benjamin P; Wilson, Daniel J; Aldrich, Courtney C

2016-01-01

Adenylation is a crucial enzymatic process in the biosynthesis of nonribosomal peptide synthetase (NRPS) derived natural products. Adenylation domains are considered the gatekeepers of NRPSs since they select, activate, and load the carboxylic acid substrate onto a downstream peptidyl carrier protein (PCP) domain of the NRPS. We describe a coupled continuous kinetic assay for NRPS adenylation domains that substitutes the PCP domain with hydroxylamine as the acceptor molecule. The pyrophosphate released from the first-half reaction is then measured using a two-enzyme coupling system, which detects conversion of the chromogenic substrate 7-methylthioguanosine (MesG) to 7-methylthioguanine. From profiling substrate specificity of unknown or engineered adenylation domains to studying chemical inhibition of adenylating enzymes, this robust assay will be of widespread utility in the broad field NRPS enzymology.

Hydroxylamine enhances glucose uptake in C2C12 skeletal muscle cells through the activation of insulin receptor substrate 1.

PubMed

Kimura, Taro; Kato, Eisuke; Machikawa, Tsukasa; Kimura, Shunsuke; Katayama, Shinji; Kawabata, Jun

2014-02-28

Diabetes mellitus is a global disease, and the number of patients with it is increasing. Of various agents for treatment, those that directly act on muscle are currently attracting attention because muscle is one of the main tissues in the human body, and its metabolism is decreased in type II diabetes. In this study, we found that hydroxylamine (HA) enhances glucose uptake in C2C12 myotubes. Analysis of HA's mechanism revealed the involvement of IRS1, PI3K and Akt that is related to the insulin signaling pathway. Further investigation about the activation mechanism of insulin receptor or IRS1 by HA may provide a way to develop a novel anti-diabetic agent alternating to insulin. Copyright © 2014 Elsevier Inc. All rights reserved.

Accumulation of True Single Strand Breaks and AP sites in Base Excision Repair Deficient Cells

PubMed Central

Luke, April M.; Chastain, Paul D.; Pachkowski, Brian F.; Afonin, Valeriy; Takeda, Shunichi; Kaufman, David G.; Swenberg, James A.; Nakamura, Jun

2010-01-01

Single strand breaks (SSBs) are one of the most frequent DNA lesions caused by endogenous and exogenous agents. The most utilized alkaline-based assays for SSB detection frequently give false positive results due to the presence of alkali-labile sites that are converted to SSBs. Methoxyamine, an acidic O-hydroxylamine, has been utilized to measure DNA damage in cells. However, the neutralization of methoxyamine is required prior to usage. Here we developed a convenient, specific SSB assay using alkaline gel electrophoresis (AGE) coupled with a neutral O-hydroxylamine, O-(tetrahydro-2H-pyran-2-yl)hydroxylamine (OTX). OTX stabilizes abasic sites (AP sites) to prevent their alkaline incision while still allowing for strong alkaline DNA denaturation. DNA from DT40 and isogenic polymerase β null cells exposed to methyl methanesulfonate were applied to the OTX-coupled AGE (OTX-AGE) assay. Time-dependent increases in SSBs were detected in each cell line with more extensive SSB formation in the null cells. These findings were supported by an assay that indirectly detects SSBs through measuring NAD(P)H depletion. An ARP-slot blot assay demonstrated a significant time-dependent increase in AP sites in both cell lines by 1 mM MMS compared to control. Furthermore, the Pol β-null cells displayed greater AP site formation than the parental DT40 cells. OTX use represents a facile approach for assessing SSB formation, whose benefits can also be applied to other established SSB assays. PMID:20851134

Evidence for an Elongation/Reduction/C1-Elimination Pathway in the Biosynthesis of n-Heptane in Xylem of Jeffrey Pine.

PubMed Central

Savage, T. J.; Hristova, M. K.; Croteau, R.

1996-01-01

The biosynthetic pathway to n-heptane was investigated by examining the effect of the [beta]-keto acyl-acyl carrier protein synthase inhibitor (2R,3S)-2,3-epoxy-4-oxo-7E,10E-dodecadienamide (cerulenin), a thiol reagent ([beta]-mercaptoethanol), and an aldehydetrapping reagent (hydroxylamine) on the biosynthesis of n-[14C]heptane and putative intermediates in xylem sections of Jeffrey pine (Pinus jeffreyi Grev.& Balf.) incubated with [14C]acetate. Cerulenin inhibited C18 fatty acid biosynthesis but had relatively little effect on radiolabel incorporation into C8 fatty acyl groups and n-heptane. [beta]-Mercaptoethanol inhibited n-heptane biosynthesis, with a corresponding accumulation of radiolabel into both octanal and 1-octanol, whereas hydroxylamine inhibited both n-heptane and 1-octanol biosynthesis, with radiolabel accumulation in octyl oximes. [14C]Octanal was converted to both n-heptane and 1-octanol when incubated with xylem sections, whereas [14C]1-octanol was converted to octanal and n-heptane in a hydroxylamine-sensitive reaction. These results suggest a pathway for the biosynthesis of n-heptane whereby acetate is polymerized via a typical fatty acid synthase reaction sequence to yield a C8 thioester, which subsequently undergoes a two-electron reduction to generate a free thiol and octanal, the latter of which alternately undergoes an additional, reversible reduction to form 1-octanol or loss of C1 to generate n-heptane. PMID:12226360

Modulation of oxidative damage by nitroxide free radicals.

PubMed

Dragutan, Ileana; Mehlhorn, Rolf J

2007-03-01

Piperidine nitroxides like 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) are persistent free radicals in non-acidic aqueous solutions and organic solvents that may have value as therapeutic agents in medicine. In biological environments, they undergo mostly reduction to stable hydroxylamines but can also undergo oxidation to reactive oxoammonium compounds. Reactions of the oxoammonium derivatives could have adverse consequences including chemical modification of vital macromolecules and deleterious effects on cell signaling. An examination of their reactivity in aqueous solution has shown that oxoammonium compounds can oxidize almost any organic as well as many inorganic molecules found in biological systems. Many of these reactions appear to be one-electron transfers that reduce the oxoammonium to the corresponding nitroxide species, in contrast to a prevalence of two-electron reductions of oxoammonium in organic solvents. Amino acids, alcohols, aldehydes, phospholipids, hydrogen peroxide, other nitroxides, hydroxylamines, phenols and certain transition metal ions and their complexes are among reductants of oxoammonium, causing conversion of this species to the paramagnetic nitroxide. On the other hand, thiols and oxoammonium yield products that cannot be detected by ESR even under conditions that would oxidize hydroxylamines to nitroxides. These products may include hindered secondary amines, sulfoxamides and sulfonamides. Thiol oxidation products other than disulfides cannot be restored to thiols by common enzymatic reduction pathways. Such products may also play a role in cell signaling events related to oxidative stress. Adverse consequences of the reactions of oxoammonium compounds may partially offset the putative beneficial effects of nitroxides in some therapeutic settings.

DISTRIBUTION OF ACTINIDES BETWEEN THE AQUEOUS AND ORGANIC PHASES IN THE TALSPEAK PROCESS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T.; Kyser, E.

2010-09-02

One objective of the US Department of Energy's Office of Nuclear Energy (DOE-NE) is the development of sustainable nuclear fuel cycles which improve uranium resource utilization, maximize energy generation, minimize waste generation, improve safety, and complement institutional measures limiting proliferation risks. Activities in progress which support this objective include the development of advanced separation technologies to recover the actinides from used nuclear fuels. With the increased interest in the development of technology to allow closure of the nuclear fuel cycle, the TALSPEAK process is being considered for the separation of Am and Cm from the lanthanide fission products in amore » next generation reprocessing plant. However, at this time, the level of understanding associated with the chemistry and the control of the process variables is not acceptable for deployment of the process on an industrial scale. To address this issue, DOE-NE is supporting basic scientific studies focused on the TALSPEAK process through its Fuel Cycle Research and Development (R&D) program. One aspect of these studies is an experimental program at the Savannah River National Laboratory (SRNL) in which temperature-dependent distribution coefficients for the extraction of actinide elements in the TALSPEAK process were measured. The data were subsequently used to calculate conditional enthalpies and entropies of extraction by van't Hoff analysis to better understand the thermodynamic driving forces for the TALSPEAK process. In the SRNL studies, the distribution of Pu(III) in the TALSPEAK process was of particular interest. A small amount of Pu(III) would be present in the feed due to process losses and valence adjustment in prior recovery operations. Actinide elements such as Np and Pu have multiple stable oxidation states in aqueous solutions; therefore the oxidation state for these elements must be controlled in the TALSPEAK process, as the extraction chemistry is dependent upon the actinide's valence. Since our plans included the measurement of Pu(III) distribution coefficients using a Np(V) solution containing small amounts of {sup 238}Pu, it was necessary to demonstrate that the desired oxidation states of Np and Pu are produced and could be stabilized in a buffered lactate solution containing diethylenetriaminepentaacetic (DTPA). The stability of Np(V) and Pu(III) in lactic acid/DTPA solutions was evaluated by ultraviolet-visible (UV-vis) spectroscopy. To perform the evaluation, Np and Pu were added to solutions containing either hydroxylamine nitrate (HAN) or ferrous sulfamate (FS) as the reductant and nominally 1.5 M lactic acid/0.05 M DTPA. The pH of the solution was subsequently adjusted to nominally 2.8 as would be performed in the TALSPEAK process. In the valence adjustment study, we found that it was necessary to reduce Pu to Pu(III) prior to combining with the lactic acid and DTPA. The Pu reduction was performed using either HAN or FS. When FS was used, Np was reduced to Np(IV). The spectroscopic studies showed that Np(V) and Pu(III) are not stable in lactic acid/DTPA solutions. The stability of Np(IV)- and Pu(IV)-DTPA complexes are much greater than the stability of the Np(V)- and Pu(III)-DTPA complexes, and as a result, Np is slowly reduced to Np(IV) and Pu is slowly oxidized to Pu(IV) due to the reduced activity of the more stable complexes. When Np(V) was added to a solution containing a 1.5 M lactic acid/ammonium lactate buffer and 0.05 M DTPA, approximately 50% of the Np was reduced to Np(IV) in the first day. The fraction of Np(V) in the solution continued to diminish with time and was essentially reduced to Np(IV) after one week. When Pu(III) was added to a lactic acid/DTPA solution of the same composition, the spectrum recorded following at least two days after preparation of the solution continued to show some sign of Pu(III). The Pu(III) was completely oxidized to Pu(IV) after 3-4 days. The UV-vis spectroscopy demonstrated that Np(V) and Pu(III) were the predominate valences in the lactic acid/DTPA solution for the better part of a day following solution preparation. Based on these results, we chose to initially add HAN to the actinide tracer solution prepared for the distribution coefficient measurements (to produce Pu(III)) prior to combining with lactic acid and DTPA. The distribution coefficient measurements were expected to be complete in 2-3 h; therefore, Np(V) and Pu(III) valences would predominate in the solution during this time. Prior to adding the HAN to the actinide tracers, we added sufficient Am(III) activity to allow the measurement of distribution coefficients during the extraction experiments. Protactinium (V) distribution coefficients were also measured using the activity which was in secular equilibrium with the {sup 237}Np. The actinide distribution coefficients were measured at pH 2.8 and 3.5 and covered a range of temperatures from nominally 20 to 60 C.« less

Synthesis of perfluoroalkylether oxadiazole elastomers

NASA Technical Reports Server (NTRS)

Rosser, R. W.; Korus, R. A.; Shalhoub, I. M.; Kwong, H.

1979-01-01

A method for the simultaneous chain extension and crosslinking of perfluoroalkylethers which yields a thermally stable perfluoroalkylether oxadiazole elastomer crosslinked by trifunctional perfluoroalkylether-1,3,5-triazine is reported. In the preparation, hydroxylamine crystals prepared from hydroxylamine hydrochloride to which sodium butoxide had been added is mixed with perfluoroalkylether dinitrile to obtain the monomer, as the nitrile is converted to amidoxime. Monomers are heated at 140 to 200 C to form poly(perfluoroalkylether oxadiazole) with a 1,2,4-oxadiazole structure by a step-growth polymerization reaction. Simultaneous chain extension and crosslinking are observed to occur when the purified monomer is heated directly and when the remaining nitrile in the monomer is allowed to react with excess ammonia to form the corresponding amidine, which is then heated. Weight loss studies show the thermal stability of the perfluoroalkylether elastomer to be generally better than fluorosilicone or polyester elastomers, especially in air, indicating its potential usefulness for high-performance elastomeric applications.

On the Reaction of Carbonyl Diphosphonic Acid with Hydroxylamine and O-alkylhydroxylamines: Unexpected Degradation of P-C-P Bridge.

PubMed

Khomich, Olga A; Yanvarev, Dmitry V; Novikov, Roman A; Kornev, Alexey B; Puljulla, Elina; Vepsäläinen, Jouko; Khomutov, Alex R; Kochetkov, Sergey N

2017-06-23

Derivatives of methylenediphosphonic acid possess wide spectra of biological activities and are used in enzymology as research tools as well as in practical medicine. Carbonyl diphosphonic acid is a promising starting building block for synthesis of functionally substituted methylenediphosphonates. Investigation of the interaction of carbonyl diphosphonic acid with hydroxylamine clearly demonstrates that it is impossible to isolate oxime within the pH range 2-12, while only cyanophosphonic and phosphoric acids are the products of the fast proceeding Beckmann-like fragmentation. In the case of O -alkylhydroxylamines, corresponding alcohols are found in the reaction mixtures in addition to cyanophosphonic and phosphoric acids. Therefore, two residues of phosphonic acid being attached to a carbonyl group provide new properties to this carbonyl group, making its oximes very unstable. This principally differs carbonyl diphosphonic acid from structurally related phosphonoglyoxalic acid and other α-ketophosphonates.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, E.L.; Singh, J.C.; Jacobson, K.L.

Cholinergic-mediated amylase release in mouse parotid acini was augmented by forskolin; the potency but not the maximal response to carbachol was altered. Amylase released by carbachol plus forskolin was dependent on extracellular calcium and was mimicked by the calcium ionophore, A23187 plus forskolin. Forskolin was also shown to enhance carbachol-stimulated /sup 45/Ca/sup 2 +/ uptake into isolated acini. Hydroxylamine, nitroprusside, and 8-bromo-c-GMP each in combination with forskolin mimicked the effects of carbachol plus forskolin on amylase release. In the presence of carbachol (10/sup -8/M) forskolin did not augment c-AMP levels. However, in the presence of carbachol (5 x 10/sup -7/more » M) or hydroxylamine (50 ..mu..M) forskolin did significantly augment c-AMP accumulation. These results suggest that calcium and c-GMP may mediate the augmentation of cholinergic-mediated amylase release by effects on c-AMP metabolism. 21 references, 1 figure, 3 tables.« less

[Spectral sensitivity and visual pigments of the coastal crab Hemigrapsus sanguineus].

PubMed

Shukoliukov, S A; Zak, P P; Kalamkarov, G R; Kalishevich, O O; Ostrovskiĭ, M A

1980-01-01

It has been shown that the compound eye of the coastal crab has one photosensitive pigment rhodopsin and screening pigments, black and orange one. The orange pigment has lambda max = 480 nm, rhodopsin in digitonin is stable towards hydroxylamin action, has lambda max = 490-495 nm and after bleaching is transformed into free retinene and opsin. The pigments with lambda max = 430 and 475 nm of the receptor part of the eye are also solubilized. These pigments are not photosensitive but they dissociate under the effect of hydroxylamine. The curye of spectral sensitivity of the coastal crab has the basic maximum at approximately 525 nm and the additional one at 450 nm, which seems to be provided by a combination of the visual pigment--rhodopsin (lambda max 500 nm) with a carotinoid filter (lambda max 480-490). Specific features of the visual system of coastal crab are discussed.

Carbon-supported iron complexes as electrocatalysts for the cogeneration of hydroxylamine and electricity in a NO-H2 fuel cell: A combined electrochemical and density functional theory study

NASA Astrophysics Data System (ADS)

Sheng, Xia; Alvarez-Gallego, Yolanda; Dominguez-Benetton, Xochitl; Baert, Kitty; Hubin, Annick; Zhao, Hailiang; Mihaylov, Tzvetan T.; Pierloot, Kristine; Vankelecom, Ivo F. J.; Pescarmona, Paolo P.

2018-06-01

Carbon-supported iron complexes were investigated as electrocatalysts for the reduction of nitric oxide (NO) in a H2-NO fuel cell conceived for the production of hydroxylamine (NH2OH) with concomitant generation of electricity. Two types of iron complexes with tetradentate ligands, namely bis(salicylidene)ethylenediimine (Salen) and phthalocyanine (Pc), supported on activated carbon or graphite were prepared and evaluated as electrocatalysts, either without further treatment or after pyrolysis at 700 °C. The performance in the reduction of NO of gas diffusion cathodes based on these electrocatalysts was investigated in an electrochemical half cell (3-electrode configuration) using linear sweep voltammetry (LSV). The most promising electrocatalysts were studied further by chronoamperometric experiments in a H2-NO fuel cell, which allowed comparison in terms of power output and hydroxylamine production. Depending on the concentration of the NO feed (6 or 18%), the best electrocatalytic performance was delivered either by FePc or FeSalen. The gas diffusion electrode based on FeSalen supported on activated carbon with 0.3 wt% Fe-loading provided the highest current density (86 A/m2) and the best current efficiency (43%) towards the desired NH2OH when operating at the higher NO concentration (18%). Moreover, FeSalen offers the advantage of being cheaper than FePc. The experimental work was complemented by density functional theory (DFT) calculations, which allowed to shed more light on the reaction mechanism for the reduction of nitric oxide at the atomistic level.

CuH-catalysed hydroamination of arylalkynes with hydroxylamine esters – a computational scrutiny of rival mechanistic pathways† †Electronic supplementary information (ESI) available: Complete account of all examined pathways, computational details, full description of reported key species (energies and Cartesian coordinates in angstroms). See DOI: 10.1039/c7sc01107e Click here for additional data file.

PubMed Central

Tobisch, Sven

2017-01-01

An in-depth computational mechanistic probe of the CuH-mediated hydroamination of internal arylalkynes with an archetype hydroxylamine ester and hydrosilane by a (Xantphos)CuH catalyst (Xantphos ≡ {P^P} ≡ 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) is presented. This first comprehensive computational study of the CuH-mediated electrophilic alkyne hydroamination has identified the most accessible pathway for the rival avenues for direct and reductive hydroamination. The mechanistic picture derived from smooth energy profiles obtained by employing a reliable computational protocol applied to a realistic catalyst model conforms to all available experimental data. The crucial vinyl- and alkylcopper intermediates were found to display a distinct chemodivergence in their reactivity towards amine electrophile and alcohol, which ensures the successful formation of α-branched alkylamines together with (E)-enamines. On the one hand, the vinylcopper is somewhat preferably approached by the alcohol, thereby rendering the reductive hydroamination avenue favourable in the presence of both amine electrophile and alcohol. In contrast, the greater kinetic demands for protonation versus electrophilic amination predicted for the alkylcopper prevents the reductive hydroamination avenue to become non-productive. Electronically modified hydroxylamine esters are found to influence the chemoselectivity in reactivity towards amine electrophile and alcohol achievable for the vinyl- and alkylcopper, thereby offering an opportunity for process improvement. PMID:28660063

Metagenomic Evidence for the Presence of Comammox Nitrospira-Like Bacteria in a Drinking Water System.

PubMed

Pinto, Ameet J; Marcus, Daniel N; Ijaz, Umer Zeeshan; Bautista-de Lose Santos, Quyen Melina; Dick, Gregory J; Raskin, Lutgarde

2016-01-01

We report metagenomic evidence for the presence of a Nitrospira-like organism with the metabolic potential to perform the complete oxidation of ammonia to nitrate (i.e., it is a complete ammonia oxidizer [comammox]) in a drinking water system. This metagenome bin was discovered through shotgun DNA sequencing of samples from biologically active filters at the drinking water treatment plant in Ann Arbor, MI. Ribosomal proteins, 16S rRNA, and nxrA gene analyses confirmed that this genome is related to Nitrospira-like nitrite-oxidizing bacteria. The presence of the full suite of ammonia oxidation genes, including ammonia monooxygenase and hydroxylamine dehydrogenase, on a single ungapped scaffold within this metagenome bin suggests the presence of recently discovered comammox potential. Evaluations based on coverage and k-mer frequency distribution, use of two different genome-binning approaches, and nucleic acid and protein similarity analyses support the presence of this scaffold within the Nitrospira metagenome bin. The amoA gene found in this metagenome bin is divergent from those of canonical ammonia and methane oxidizers and clusters closely with the unusual amoA gene of comammox Nitrospira. This finding suggests that previously reported imbalances in abundances of nitrite- and ammonia-oxidizing bacteria/archaea may likely be explained by the capacity of Nitrospira-like organisms to completely oxidize ammonia. This finding might have significant implications for our understanding of microbially mediated nitrogen transformations in engineered and natural systems. IMPORTANCE Nitrification plays an important role in regulating the concentrations of inorganic nitrogen species in a range of environments, from drinking water and wastewater treatment plants to the oceans. Until recently, aerobic nitrification was considered to be a two-step process involving ammonia-oxidizing bacteria or archaea and nitrite-oxidizing bacteria. This process requires close cooperation between these two functional guilds for complete conversion of ammonia to nitrate, without the accumulation of nitrite or other intermediates, such as nitrous oxide, a potent greenhouse gas. The discovery of a single organism with the potential to oxidize both ammonia and nitrite adds a new dimension to the current understanding of aerobic nitrification, while presenting opportunities to rethink nitrogen management in engineered systems.

Evidence for biological nitrification inhibition in Brachiaria pastures

PubMed Central

Subbarao, G. V.; Nakahara, K.; Hurtado, M. P.; Ono, H.; Moreta, D. E.; Salcedo, A. F.; Yoshihashi, A. T.; Ishikawa, T.; Ishitani, M.; Ohnishi-Kameyama, M.; Yoshida, M.; Rondon, M.; Rao, I. M.; Lascano, C. E.; Berry, W. L.; Ito, O.

2009-01-01

Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named “brachialactone,” this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a γ-lactone ring. It contributed 60–90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NH4+) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NH4+. Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment. PMID:19805171

Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system.

PubMed

Li, Hua; Liang, Xinqiang; Chen, Yingxu; Lian, Yanfeng; Tian, Guangming; Ni, Wuzhong

2008-01-01

DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4(+)-N and NO3(-)-N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4(+)-N concentrations by 19.1%--24.3%, but reduced the mean NO3(-)-N concentrations by 44.9%--56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%--30.9%, 14.9%--43.5%, and 14.7%--31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3(-)-N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.

The Role of Hydroxylamine as a Nitrification Intermediate in N-nitrosamine Formation

EPA Science Inventory

The formation of N-nitrosamines, and in particular N-nitrosodimethylamine (NDMA), in drinking water systems that use chloramines is a concern because of their potential carcinogenicity and occurrences in finished waters at toxicologically relevant levels. The widely accepted mech...

Chemical heterogeneity as a result of hydroxylamine cleavage of a fusion protein of human insulin-like growth factor I.

PubMed Central

Canova-Davis, E; Eng, M; Mukku, V; Reifsnyder, D H; Olson, C V; Ling, V T

1992-01-01

Recombinant DNA techniques were used to biosynthesize human insulin-like growth factor I (hIGF-I) as a fusion protein wherein the fusion polypeptide is an IgG-binding moiety derived from staphylococcal protein A. This fusion protein is produced in Escherichia coli and secreted into the fermentation broth. In order to release mature recombinant-derived hIGF-I (rhIGF-I), the fusion protein is treated with hydroxylamine, which cleaves a susceptible Asn-Gly bond that has been engineered into the fusion protein gene. Reversed-phase h.p.l.c. was used to estimate the purity of the rhIGF-I preparations, especially for the quantification of the methionine sulphoxide-containing variant. It was determined that hydroxylamine cleavage of the fusion protein produced, as a side reaction, hydroxamates of the asparagine and glutamine residues in rhIGF-I. Although isoelectric focusing was effective in detecting, and reversed-phase h.p.l.c. for producing enriched fractions of the hydroxamate variants, ion-exchange chromatography was a more definitive procedure, as it allowed quantification and facile removal of these variants. The identity of the variants as hydroxamates was established by Staphylococcus aureus V8 proteinase digestion, followed by m.s., as the modification was transparent to amino acid and N-terminal sequence analyses. The biological activity of rhIGF-I was established by its ability to incorporate [3H]thymidine into the DNA of BALB/c373 cells and by a radioreceptor assay utilizing human placental membranes. Both assays demonstrate that the native, recombinant and methionine sulphoxide and hydroxamate IGF-I variants are essentially equipotent. Images Fig. 2. PMID:1637301

A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate.

PubMed

Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping

2014-08-07

A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

The reaction of monochloramine and hydroxylamine: implications for ammonia–oxidizing bacteria in chloraminated drinking water

EPA Science Inventory

Drinking water chloramine use may promote ammonia–oxidizing bacteria (AOB) growth because of naturally occurring ammonia, residual ammonia remaining from chloramine formation, and ammonia released from chloramine decay and demand. A rapid chloramine residual loss is often associa...

The Role of Hydroxylamine as a Nitrification Intermediate in N-Nitrosamine Formation- Indianapolis

EPA Science Inventory

The formation of N-nitrosamines, and in particular N-nitrosodimethylamine (NDMA), in drinking water systems that use chloramines is a concern because of their potential carcinogenicity and occurrences in finished waters at toxicologically relevant levels. The widely accepted mech...

Gold nanoparticle assemblies of controllable size obtained by hydroxylamine reduction at room temperature

NASA Astrophysics Data System (ADS)

Tódor, István Sz.; Szabó, László; Marişca, Oana T.; Chiş, Vasile; Leopold, Nicolae

2014-12-01

Colloidal nanoparticle assemblies (NPAs) were obtained in a one-step procedure, by reduction of HAuCl4 by hydroxylamine hydrochloride, at room temperature, without the use of any additional nucleating agent. By changing the order of the reactants, NPAs with mean size of 20 and 120 nm were obtained. Because of their size and irregular popcorn like shape, the larger size NPAs show absorption in the NIR spectral region. The building blocks of the resulted nanoassemblies are spherical nanoparticles with diameters of 4-8 and 10-30 nm, respectively. Moreover, by stabilizing the colloid with bovine serum albumin at different time moments after synthesis, NPAs of controlled size between 20 and 120 nm, could be obtained. The NPAs were characterized using UV-Vis spectroscopy, TEM and SEM electron microscopies. In addition, the possibility of using the here proposed NPAs as surface-enhanced Raman scattering (SERS) substrate was assessed and found to provide a higher enhancement compared to conventional citrate-reduced nanoparticles.

An experimental and theoretical study of reaction mechanisms between nitriles and hydroxylamine.

PubMed

Vörös, Attila; Mucsi, Zoltán; Baán, Zoltán; Timári, Géza; Hermecz, István; Mizsey, Péter; Finta, Zoltán

2014-10-28

The industrially relevant reaction between nitriles and hydroxylamine yielding amidoximes was studied in different molecular solvents and in ionic liquids. In industry, this procedure is carried out on the ton scale in alcohol solutions and the above transformation produces a significant amount of unexpected amide by-product, depending on the nature of the nitrile, which can cause further analytical and purification issues. Although there were earlier attempts to propose mechanisms for this transformation, the real reaction pathway is still under discussion. A new detailed reaction mechanistic explanation, based on theoretical and experimental proof, is given to augment the former mechanisms, which allowed us to find a more efficient, side-product free procedure. Interpreting the theoretical results obtained, it was shown that the application of specific imidazolium, phosphonium and quaternary ammonium based ionic liquids could decrease simultaneously the reaction time while eliminating the amide side-product, leading to the targeted product selectively. This robust and economic procedure now affords a fast, selective amide free synthesis of amidoximes.

Localized hydroxylamine mutagenesis, and cotransduction of threonine and lysine genes, in Streptomyces venezuelae.

PubMed Central

Stuttard, C

1983-01-01

A lysate of the generalized transducing phage SV1, grown on the prototrophic type strain 10712 of Streptomyces venezuelae, was mutagenized with hydroxylamine and used to transduce a lysineless auxotroph to lysine independence on supplemented minimal agar. A complex threonine mutant, strain VS95, was isolated from among the transductants and was shown to be carrying at least two different thr mutations. These were about 50% cotransducible with alleles of four independently isolated lysA mutations, as were two other independently isolated threonine mutations, thr-1 and hom-5. The location of thr genes close to lysA occurs in at least three other streptomycetes, but apparently not in Streptomyces coelicolor A3(2), in which the lysA and thr loci are at diametrically opposite locations on the linkage map. This first observation of cotransduction between loci governing the biosynthesis of different amino acids in the genus Streptomyces demonstrates the feasibility of fine-structure genetic analysis by transduction in these antibiotic-producing bacteria. PMID:6411685

Activation of Oxygen and Hydrogen Peroxide by Copper(II) Coupled with Hydroxylamine for Oxidation of Organic Contaminants.

PubMed

Lee, Hongshin; Lee, Hye-Jin; Seo, Jiwon; Kim, Hyung-Eun; Shin, Yun Kyung; Kim, Jae-Hong; Lee, Changha

2016-08-02

This study reports that the combination of Cu(II) with hydroxylamine (HA) (referred to herein as Cu(II)/HA system) in situ generates H2O2 by reducing dissolved oxygen, subsequently producing reactive oxidants through the reaction of Cu(I) with H2O2. The external supply of H2O2 to the Cu(II)/HA system (i.e., the Cu(II)/H2O2/HA system) was found to further enhance the production of reactive oxidants. Both the Cu(II)/HA and Cu(II)/H2O2/HA systems effectively oxidized benzoate (BA) at pH between 4 and 8, yielding a hydroxylated product, p-hydroxybenzoate (pHBA). The addition of a radical scavenger, tert-butyl alcohol, inhibited the BA oxidation in both systems. However, electron paramagnetic resonance (EPR) spectroscopy analysis indicated that (•)OH was not produced under either acidic or neutral pH conditions, suggesting that the alternative oxidant, cupryl ion (Cu(III)), is likely a dominant oxidant.

Estimation of the nitric oxide formed from hydroxylamine by Nitrosomonas

PubMed Central

Anderson, J. H.

1965-01-01

1. Nitric oxide that was produced by reducing nitrite with an excess of acidified potassium iodide under nitrogen in Warburg respirometer flasks was rapidly absorbed by a solution of permanganate in sodium hydroxide held in the side arm. A small amount of nitrous oxide (or nitrogen) that was also produced was not absorbed. 2. By using a quantitative method for the recovery of nitrite from samples of the alkaline permanganate, it was found that the sum of the nitrite N formed and the residual nitrous oxide N was equivalent to the nitrite N used to generate the gases. These results showed that alkaline permanganate completely oxidized nitric oxide to nitrite. The method was suitable for determining 0·4–20 μmoles of nitric oxide. 3. The technique was used to determine the nitric oxide content of the nitrogenous gas that was produced anaerobically from hydroxylamine by an extract of the autotrophic nitrifying micro-organism Nitrosomonas in the presence of methylene blue as electron acceptor. PMID:14342235

CSO and CARMA Observations of L1157. I. A Deep Search for Hydroxylamine (NH2OH)

NASA Astrophysics Data System (ADS)

McGuire, Brett A.; Carroll, P. Brandon; Dollhopf, Niklaus M.; Crockett, Nathan R.; Corby, Joanna F.; Loomis, Ryan A.; Burkhardt, Andrew M.; Shingledecker, Christopher; Blake, Geoffrey A.; Remijan, Anthony J.

2015-10-01

A deep search for the potential glycine precursor hydroxylamine (NH2OH) using the Caltech Submillimeter Observatory (CSO) at λ = 1.3 mm and the Combined Array for Research in Millimeter-wave Astronomy at λ = 3 mm is presented toward the molecular outflow L1157, targeting the B1 and B2 shocked regions. We report non-detections of NH2OH in both sources. We perform a non-LTE analysis of CH3OH observed in our CSO spectra to derive the kinetic temperatures and densities in the shocked regions. Using these parameters, we derive upper limit column densities of NH2OH of ≤1.4 × 1013 cm-2 and ≤1.5 × 1013 cm-2 toward the B1 and B2 shocks, respectively, and upper limit relative abundances of {N}{{NH}2{OH}}/{N}{{{H}}2}≤slant 1.4× {10}-8 and ≤1.5 × 10-8, respectively.

An oxazetidine amino acid for chemical protein synthesis by rapid, serine-forming ligations

NASA Astrophysics Data System (ADS)

Pusterla, Ivano; Bode, Jeffrey W.

2015-08-01

Amide-forming ligation reactions allow the chemical synthesis of proteins by the union of unprotected peptide segments, and enable the preparation of protein derivatives not accessible by expression or bioengineering approaches. The native chemical ligation (NCL) of thioesters and N-terminal cysteines is unquestionably the most successful approach, but is not ideal for all synthetic targets. Here we describe the synthesis of an Fmoc-protected oxazetidine amino acid for use in the α-ketoacid-hydroxylamine (KAHA) amide ligation. When incorporated at the N-terminus of a peptide segment, this four-membered cyclic hydroxylamine can be used for rapid serine-forming ligations with peptide α-ketoacids. This ligation operates at low concentration (100 μM-5 mM) and mild temperatures (20-25 °C). The utility of the reaction was demonstrated by the synthesis of S100A4, a 12 kDa calcium-binding protein not easily accessible by NCL or other amide-forming reactions due to its primary sequence and properties.

Final Report on the Detection of Green Monopropellants

NASA Technical Reports Server (NTRS)

Gibson, Tracy L.; DeVor, Robert W.; Bauer, Brint M.; Captain, James; Coutts, Janelle L.; Surma, Jan M.

2015-01-01

In 2014, National Aeronautics and Space Administration (NASA) Kennedy Space Center (KSC) funded a project titled "Familiarization and Detection of Green Monopropellants" utilizing Independent Research and Technology Development (IR&TD) and Center Innovation Fund (CIF) funding. The purpose of the project was to evaluate methods of detection for ammonium dinitramide (ADN) and hydroxylammonium nitrate (HAN). An Engineering Services Contract (ESC) task order was created with the scope of evaluation of several methods of detecting ADN- and HAN-based propellants, as well as development of methods for detection. Detection methods include developed methods such as colorimetric indicating absorbent socks, and commercial-off-the- shelf (COTS) units for ammonia detection. An additional goal of the task order was for ESC to become familiar with ADN's and HAN's material properties and material compatibility. Two approaches were initially investigated as possible methods for the detection of HAN (or AFM315E) and ADN (or LMP-103S). These approaches were colorimetric analysis and instrumentation-based COTS vapor sensors utilization. Initial testing showed that the relatively non-existent vapor pressure of the AF-M315E (of which HAN is a major component) propellant would make the use of COTS sensors difficult for real-time area monitoring of HAN; a small response was detected through the use of active COTS sensors, including the RAE Systems MultiRAE Lite and Drager X-act (registered) 5000, but the levels detected were below the threshold limit value for the toxic gas ammonia. Therefore, a detection system ased upon a colorimetric indicator impregnated into an absorbent material was developed. Preliminary analysis (ESC-245-FDG-001) identified a particularly outstanding candidate as a colorimetric indicator for the detection of the presence of AF-M315E in the form of a Methyl Red (Basic) indicator. Materials impregnated with this indicator exhibit significant color change and the materials are not susceptible to interference from exposure to water or carbon dioxide. The completed detection system for HAN/AF-M315E consists of absorbent socks packed with Fisher Universal Spill Absorbent capable of absorbing and containing any propellant spills that they come into contact with along with indicating wipes. The absorbent socks are also chemically treated with a Methyl Red (Basic) indicator solution to provide the end user with a visual indication that a leak has occurred and proper protective precautions must be undertaken. An added benefit of this detection system is that the absorbent socks should neutralize/absorb any commodity that it comes into contact with (until saturation is reached). Additional adsorbent socks can be deployed until a color change is not seen, indicating that the HAN/AF-M315E contamination has been contained. The indicating wipes provide the user the opportunity to wipe surfaces to determine if there is any HAN/AF-M315E or HAN/AFM315E residue present. The wipes should allow the detection of fuel levels that may be too small to detect with the absorbent socks. The development of a detection system for the ADN/LMP-103S focused on the use of various COTS sensors used as real-time area monitoring devices and personal dosimeters. These COTS based sensor systems were of several different types, including both actively pumped and diffusion-based passive systems, as well as a "rope"-type chemical sensing cable. The results highlighted some of the major differences between the two monopropellants undergoing evaluation. Unlike HAN, ADN (which is the major constituent of LMP-103S) exhibits a much more volatile nature in comparison to AF-M315E. In fact, testing showed that a large percentage of the fuel was lost during the sampling measurement (greater than 10 percent by mass); although this testing cannot tell if the volatile component is the ADN itself or another component of the monopropellant solution. Not surprisingly, all four of the procured vapor-based COTS sensors showed positive results when exposed to solutions of the LMP-103S (ESC-245-FDG-002). The completed detection system for ADN/LMP-103S consists of a combination of two of the tested COTS sensor systems, the RAE Systems MultiRAE Lite and the BW Technologies GasAlert Extreme. These systems are meant to be used in conjunction with one another, which allows for the end-user to have both real-time area monitoring (MultiRAE Lite) as well as a personal dosimeter device (GasAlert Extreme) which can be worn as additional personal protective equipment. An stainless steel extension wand was fabricated and included in the detection system for the MultiRAE Lite to allow for more remote sensing, and connects via the active pumping inlet of the sensor. As stated, the final results of this testing resulted in the production of two "kits" which can be used for the detection of HAN/AF-M315E and ADN/LMP-103s (ESC-245-FDG-003).

Process for the extraction of technetium from uranium

DOEpatents

Gong, Cynthia-May S.; Poineau, Frederic; Czerwinski, Kenneth R.

2010-12-21

A spent fuel reprocessing method contacts an aqueous solution containing Technetium(V) and uranyl with an acidic solution comprising hydroxylamine hydrochloride or acetohydroxamic acid to reduce Tc(V) to Tc(II, and then extracts the uranyl with an organic phase, leaving technetium(II) in aqueous solution.

Overview of reductants utilized in nuclear fuel reprocessing/recycling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patricia Paviet-Hartmann; Catherine Riddle; Keri Campbell

2013-10-01

Most of the aqueous processes developed, or under consideration worldwide for the recycling of used nuclear fuel (UNF) utilize the oxido-reduction properties of actinides to separate them from other radionuclides. Generally, after acid dissolution of the UNF, (essentially in nitric acid solution), actinides are separated from the raffinate by liquid-liquid extraction using specific solvents, associated along the process, with a particular reductant that will allow the separation to occur. For example, the industrial PUREX process utilizes hydroxylamine as a plutonium reductant. Hydroxylamine has numerous advantages: not only does it have the proper attributes to reduce Pu(IV) to Pu(III), but itmore » is also a non-metallic chemical that is readily decomposed to innocuous products by heating. However, it has been observed that the presence of high nitric acid concentrations or impurities (such as metal ions) in hydroxylamine solutions increase the likelihood of the initiation of an autocatalytic reaction. Recently there has been some interest in the application of simple hydrophilic hydroxamic ligands such as acetohydroxamic acid (AHA) for the stripping of tetravalent actinides in the UREX process flowsheet. This approach is based on the high coordinating ability of hydroxamic acids with tetravalent actinides (Np and Pu) compared with hexavalent uranium. Thus, the use of AHA offers a route for controlling neptunium and plutonium in the UREX process by complexant based stripping of Np(IV) and Pu(IV) from the TBP solvent phase, while U(VI) ions are not affected by AHA and remain solvated in the TBP phase. In the European GANEX process, AHA is also used to form hydrophilic complexes with actinides and strip them from the organic phase into nitric acid. However, AHA does not decompose completely when treated with nitric acid and hampers nitric acid recycling. In lieu of using AHA in the UREX + process, formohydroxamic acid (FHA), although not commercially available, hold promises as a replacement for AHA. FHA undergoes hydrolysis to formic acid which is volatile, thus allowing the recycling of nitric acid. Unfortunately, FHA powder was not stable in the experiments we ran in our laboratory. In addition, AHA and FHA also decompose to hydroxylamine which may undergo an autocatalytic reaction. Other reductants are available and could be extremely useful for actinides separation. The review presents the current plutonium reductants used in used nuclear fuel reprocessing and will introduce innovative and novel reductants that could become reducers for future research on UNF separation.« less

Genetic Variation of 25 Y-Chromosomal and 15 Autosomal STR Loci in the Han Chinese Population of Liaoning Province, Northeast China

PubMed Central

Yao, Jun; Wang, Bao-jie

2016-01-01

In the present study, we investigated the genetic characteristics of 25 Y-chromosomal and 15 autosomal short tandem repeat (STR) loci in 305 unrelated Han Chinese male individuals from Liaoning Province using AmpFISTR® Yfiler® Plus and IdentifilerTM PCR amplification kits. Population comparison was performed between Liaoning Han population and different ethnic groups to better understand the genetic background of the Liaoning Han population. For Y-STR loci, the overall haplotype diversity was 0.9997 and the discrimination capacity was 0.9607. Gene diversity values ranged from 0.4525 (DYS391) to 0.9617 (DYS385). Rst and two multi-dimensional scaling plots showed that minor differences were observed when the Liaoning Han population was compared to the Jilin Han Chinese, Beijing Han Chinese, Liaoning Manchu, Liaoning Mongolian, Liaoning Xibe, Shandong Han Chinese, Jiangsu Han Chinese, Anhui Han Chinese, Guizhou Han Chinese and Liaoning Hui populations; by contrast, major differences were observed when the Shanxi Han Chinese, Yunnan Bai, Jiangxi Han Chinese, Guangdong Han Chinese, Liaoning Korean, Hunan Tujia, Guangxi Zhuang, Gansu Tibetan, Xishuangbanna Dai, South Korean, Japanese and Hunan Miao populations. For autosomal STR loci, DP ranged from 0.9621 (D2S1338) to 0.8177 (TPOX), with PE distributing from 0.7521 (D18S51) to 0.2988 (TH01). A population comparison was performed and no statistically significant differences were detected at any STR loci between Liaoning Han, China Dong, and Shaanxi Han populations. The results showed that the 25 Y-STR and 15 autosomal STR loci in the Liaoning Han population were valuable for forensic applications and human genetics, and Liaoning Han was an independent endogenous ethnicity with a unique subpopulation structure. PMID:27483472

Transforming han: a correlational method for psychology and religion.

PubMed

Oh, Whachul

2015-06-01

Han is a destructive feeling in Korea. Although Korea accomplished significant exterior growth, Korean society is still experiencing the dark aspects of transforming han as evidenced by having the highest suicide rate in Asia. Some reasons for this may be the fragmentation between North and South Korea. If we can transform han then it can become constructive. I was challenged to think of possibilities for transforming han internally; this brings me to the correlational method through psychological and religious interpretation. This study is to challenge and encourage many han-ridden people in Korean society. Through the psychological and religious understanding of han, people suffering can positively transform their han. They can relate to han more subjectively, and this means the han-ridden psyche has an innate sacredness of potential to transform.

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2010 CFR

2010-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker...L beaker. Record sample weight. 5.3Add 100 mL of the methanol/water mixture and stir on a magnetic...

Biochar effects on gaseous losses of N2O and CH4

USDA-ARS?s Scientific Manuscript database

The flux of N2O from soil is controlled by both biological and abiotic processes resulting in production and consumption. In a recent review by Butterbach-Bahl et al., (2013), key processes that contribute to N2O formation in soils included: 1) chemical decomposition of hydroxylamine during autotrop...

Theoretical Study of Oxovanadium(IV) Complexation with Formamidoximate: Implications for the Design of Uranyl-Selective Adsorbents

DOE PAGES

Mehio, Nada; Ivanov, Alexander S.; Ladshaw, Austin P.; ...

2015-11-22

Poly(acrylamidoxime) fibers are the current state of the art adsorbent for mining uranium from seawater. However, the competition between uranyl (UO 2 2+) and vanadium ions poses a challenge to mining on the industrial scale. In this work, we employ density functional theory (DFT) and coupled-cluster methods (CCSD(T)) in the restricted formalism to investigate potential binding motifs of the oxovanadium(IV) ion (VO 2+) with the formamidoximate ligand. Consistent with experimental EXAFS data, the hydrated six-coordinate complex is predicted to be preferred over the hydrated five-coordinate complex. Here, our investigation of formamidoximate-VO 2+ complexes universally identified the most stable binding motifmore » formed by chelating a tautomerically rearranged imino hydroxylamine via the imino nitrogen and hydroxylamine oxygen. The alternative binding motifs for amidoxime chelation via a non-rearranged tautomer and 2 coordination are found to be ~11 kcal/mol less stable. Ultimately, the difference in the most stable VO 2+ and UO 2 2+ binding conformation has important implications for the design of more selective UO 2 2+ ligands.« less

Development of a headspace GC/MS analysis for carbonyl compounds (aldehydes and ketones) in household products after derivatization with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine.

PubMed

Sugaya, Naeko; Sakurai, Katsumi; Nakagawa, Tomoo; Onda, Nobuhiko; Onodera, Sukeo; Morita, Masatoshi; Tezuka, Masakatsu

2004-05-01

Carbonyl compounds (aldehydes and ketones) are suspected to be among the chemical compounds responsible for Sick Building Syndrome and Multiple Chemical Sensitivities. A headspace gas chromatography/mass spectrometry (GC/MS) analysis for these compounds was developed using derivatization of the compounds into volatile derivatives with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBOA). For GC/MS detection, two ionization modes including electron impact ionization (EI) and negative chemical ionization (NCI) were compared. The NCI mode seemed to be better because of its higher selectivity and sensitivity. This headspace GC/MS (NCI mode) was employed as analysis for aldehydes and ketones in materials (fiber products, adhesives, and printed materials). Formaldehyde was detected in the range of N.D. (not detected) to 39 microg/g; acetaldehyde, N.D. to 4.1 microg/g; propionaldehyde, N.D. to 1.0 microg/g; n-butyraldehyde, N.D. to 0.10 microg/g; and acetone, N.D. to 3.1 microg/g in the samples analyzed.

Comparison of hot hydroxylamine hydrochloride and oxalic acid leaching of stream sediment and coated rock samples as anomaly enhancement techniques

USGS Publications Warehouse

Filipek, L.H.; Chao, T.T.; Theobald, P.K.

1982-01-01

A hot hydroxylamine hydrochloride (H-Hxl) extraction in 25% acetic acid is compared with the commonly used oxalic acid extraction as a method of anomaly enhancement for Cu and Zn in samples from two very different metal deposits and climatic environments. Results obtained on minus-80-mesh stream sediments from an area near the Magruder massive sulfide deposit in Lincoln County, Georgia, where the climate is humid subtropical, indicate that H-Hxl enhances the anomaly for Cu by a factor of 2 and for Zn by a factor of 1.5, compared to the oxalic method. Analyses of Fe oxide-coated rock samples from outcrops overlying the North Silver Bell porphyry copper deposit near Tucson, Arizona, where the climate is semi-arid to arid, indicate that both techniques effectively outline the zones of hydrothermal alteration. The H-Hxl extraction can also perform well in high-carbonate or high-clay environments, where other workers have suggested that oxalic acid is not very effective. Therefore, the H-Hxl method is recommended for general exploration use. ?? 1982.

Metabolism of 4-N-Hydroxy-Cytidine in Escherichia coli

PubMed Central

Trimble, R. B.; Maley, Frank

1971-01-01

4-N-hydroxy-cytidine was found to substitute for uridine as a pyrimidine supplement for the growth of Escherichia coli Bu−. Measurement of the incorporation of 4-N-hydroxy-cytidine-2-14C into ribonucleic acid and deoxyribonucleic acid revealed that this compound was converted to cytidine or uridine before utilization. Two pathways for metabolism were considered: (i) the reduction of 4-N-hydroxy-cytidine to cytidine followed by deamination, (ii) the direct hydrolysis of hydroxylamine from 4-N-hydroxy-cytidine to yield uridine. A threefold increase in cytidine (deoxycytidine) deaminase (EC 3.5.4.5) activity, when the cells were grown on 4-N-hydroxy-cytidine, suggested the involvement of this enzyme. More direct proof was obtained by purifying the deaminase 185-fold and finding that it released hydroxylamine from 4-N-hydroxy-cytidine at one-fiftieth the rate at which ammonia was removed from cytidine. This result is consistent with the slower rate of growth of the Bu− cells on 4-N-hydroxy-cytidine than cytidine and suggests that the second pathway is the major route for utilization of this compound. PMID:4941553

Physical map location of the multicopy genes coding for ammonia monooxygenase and hydroxylamine oxidoreductase in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11.

PubMed

Hirota, R; Yamagata, A; Kato, J; Kuroda, A; Ikeda, T; Takiguchi, N; Ohtake, H

2000-02-01

Pulsed-field gel electrophoresis of PmeI digests of the Nitrosomonas sp. strain ENI-11 chromosome produced four bands ranging from 1,200 to 480 kb in size. Southern hybridizations suggested that a 487-kb PmeI fragment contained two copies of the amoCAB genes, coding for ammonia monooxygenase (designated amoCAB(1) and amoCAB(2)), and three copies of the hao gene, coding for hydroxylamine oxidoreductase (hao(1), hao(2), and hao(3)). In this DNA fragment, amoCAB(1) and amoCAB(2) were about 390 kb apart, while hao(1), hao(2), and hao(3) were separated by at least about 100 kb from each other. Interestingly, hao(1) and hao(2) were located relatively close to amoCAB(1) and amoCAB(2), respectively. DNA sequence analysis revealed that hao(1) and hao(2) shared 160 identical nucleotides immediately upstream of each translation initiation codon. However, hao(3) showed only 30% nucleotide identity in the 160-bp corresponding region.

Physical Map Location of the Multicopy Genes Coding for Ammonia Monooxygenase and Hydroxylamine Oxidoreductase in the Ammonia-Oxidizing Bacterium Nitrosomonas sp. Strain ENI-11

PubMed Central

Hirota, Ryuichi; Yamagata, Akira; Kato, Junichi; Kuroda, Akio; Ikeda, Tsukasa; Takiguchi, Noboru; Ohtake, Hisao

2000-01-01

Pulsed-field gel electrophoresis of PmeI digests of the Nitrosomonas sp. strain ENI-11 chromosome produced four bands ranging from 1,200 to 480 kb in size. Southern hybridizations suggested that a 487-kb PmeI fragment contained two copies of the amoCAB genes, coding for ammonia monooxygenase (designated amoCAB1 and amoCAB2), and three copies of the hao gene, coding for hydroxylamine oxidoreductase (hao1, hao2, and hao3). In this DNA fragment, amoCAB1 and amoCAB2 were about 390 kb apart, while hao1, hao2, and hao3 were separated by at least about 100 kb from each other. Interestingly, hao1 and hao2 were located relatively close to amoCAB1 and amoCAB2, respectively. DNA sequence analysis revealed that hao1 and hao2 shared 160 identical nucleotides immediately upstream of each translation initiation codon. However, hao3 showed only 30% nucleotide identity in the 160-bp corresponding region. PMID:10633121

Boron doped diamond sensor for sensitive determination of metronidazole: Mechanistic and analytical study by cyclic voltammetry and square wave voltammetry.

PubMed

Ammar, Hafedh Belhadj; Brahim, Mabrouk Ben; Abdelhédi, Ridha; Samet, Youssef

2016-02-01

The performance of boron-doped diamond (BDD) electrode for the detection of metronidazole (MTZ) as the most important drug of the group of 5-nitroimidazole was proven using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. A comparison study between BDD, glassy carbon and silver electrodes on the electrochemical response was carried out. The process is pH-dependent. In neutral and alkaline media, one irreversible reduction peak related to the hydroxylamine derivative formation was registered, involving a total of four electrons. In acidic medium, a prepeak appears probably related to the adsorption affinity of hydroxylamine at the electrode surface. The BDD electrode showed higher sensitivity and reproducibility analytical response, compared with the other electrodes. The higher reduction peak current was registered at pH11. Under optimal conditions, a linear analytical curve was obtained for the MTZ concentration in the range of 0.2-4.2μmolL(-1), with a detection limit of 0.065μmolL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

Haloacetonitriles: metabolism and toxicity.

PubMed

Lipscomb, John C; El-Demerdash, Ebtehal; Ahmed, Ahmed E

2009-01-01

The haloacetonitriles (HANs) exist in drinking water exclusively as byproducts of disinfection. HANs are found in drinking water more often, and in higher concentrations, when surface water is treated by chloramination. Human exposure occurs through consumption of finished drinking water; oral and dermal contact also occurs, and results from showering, swimming and other activities. HANs are reactive and are toxic to gastrointestinal tissues following oral administration. Such toxicity is characterized by GSH depletion, increased lipid peroxidation, and covalent binding of HAN-associated radioactivity to gut tissues. The presence of GSH in cells is an important protective mechanism against HAN toxicity; depletion of cellular GSH results in increased toxicity. Some studies have demonstrated an apparently synergistic effect between ROS and HAN administration, that may help explain effects observed in GI tissues. ROS are produced in gut tissues, and in vitro evidence indicates that ROS may contribute to the degradation and formation of reactive intermediates from HANs. The rationale for ROS involvement may involve HAN-induced depletion of GSH and the role of GSH in scavenging ROS. In addition to effects on GI tissues, studies show that HAN-derived radiolabel is found covalently bound to proteins and DNA in several organs and tissues. The addition of antioxidants to biologic systems protects against HAN-induced DNA damage. The protection offered by antioxidants supports the role of oxidative stress and the potential for a threshold in han-induced toxicity. However, additional data are needed to substantiate evidence for such a threshold. HANs are readily absorbed from the GI tract and are extensively metabolized. Elimination occurs primarily in urine, as unconjugated one-carbon metabolites. Evidence supports the involvement of mixed function oxidases, the cytochrome P450 enzyme family and GST, in HAN metabolism. Metabolism represents either a detoxification or bioactivation process, depending on the particular HAN and the enzyme involved. HANs can inhibit CYP2E1-mediated metabolism, an effect which may be dependent on a covalent interaction with the enzyme. In addition, HAN compounds inhibit GST-mediated conjugation, but this effect is reversible upon dialysis, indicating that the interaction does not represent covalent binding. No subchronic studies of HAN toxicity are available in the literature. However, studies show that HANs produce developmental toxicity in experimental animals. The nature of developmental toxicity is affected by the type of administration vehicle, which renders interpretation of results more difficult. Skin tumors have been found following dermal application of HANs, but oral studies for carcinogenicity are negative. Pulmonary adenomas were increased following oral administration of HANs, but the A/J strain of mice employed has a characteristically high background rate of such tumors. HANs interact with DNA to produce unscheduled DNA repair, SCE and reverse mutations in Salmonella. HANs did not induce micronuclei or cause alterations in sperm head morphology in mice, but did induce micronuclei in newts. Thus, there is concern for the potential carcinogenicity of HANs. It would be valuable to delineate any relationship between the apparent threshold for micronuclei formation in newts and the potential mechanism of toxicity involving HAN-induced oxidative stress. Dose-response studies in rodents may provide useful information on toxicity mechanisms and dose selection for longer term toxicity studies. Additional studies are warranted before drawing firm conclusions on the hazards of HAN exposure. Moreover, additional studies on HAN-DNA and HAN-protein interaction mechanisms, are needed. Such studies can better characterize the role of metabolism in toxicity of individual HANs, and delineate the role of oxidative stress, both of which enhance the capacity to predict risk. Most needed, now, are new subchronic (and chronic) toxicity studies; the results of such well-planned, controlled, conducted, interpreted and published investigations would be valuable in establishing margins of safety for HANs in human health risk assessment.

Evaluation of the Accumulation of Trace Metals (as, U, CR, CU, PB, Zn) on Iron-Manganese Coatings on in Situ Stream Pebbles and Emplaced Substrates

NASA Astrophysics Data System (ADS)

Turpin, M. M.; Blake, J.; Crossey, L. J.; Ali, A.; Hansson, L.

2015-12-01

Exposure to trace metals (As, U, Cr, Cu, Pb, Zn) has potential negative health effects on human populations and wildlife. Geothermal waters often have elevated concentrations of trace elements and understanding the geochemical cycling of these elements can be challenging. Previous studies have utilized in situ stream pebbles and glass or ceramic substrates with iron-manganese oxide coatings to understand contamination and or chemical cycling. This project's main focus is to develop an ideal tracing method using adsorption onto substrate surfaces and to define key parameters that are necessary for the phenomenon of adsorption between trace metals and these surface coatings to occur. Sampling locations include the Jemez River and Rio San Antonio in the Jemez mountains, northern New Mexico. Both streams have significant geothermal inputs. Pebbles and cobbles were gathered from the active stream channel and 6mm glass beads and 2 X1 in. ceramic plates were placed in streams for three weeks to allow for coating accumulation. Factors such as leachate type, water pH, substrate type, coating accumulation period and leach time were all considered in this experiment. It was found that of the three leachates (aqua regia, 10% aqua regia and hydroxylamine), hydroxylamine was the most effective at leaching coatings without dissolving substrates. Samples leached with aqua regia and 10% aqua regia were found to lose weight and mass over the following 5, 7, and 10 day measurements. Glass beads were determined to be more effective than in stream pebbles as an accumulation substrate: coatings were more easily controlled and monitored. Samples leached with hydroxylamine for 5 hours and 72 hours showed little difference in their leachate concentrations, suggesting that leach time has little impact on the concentration of leachate samples. This research aims to find the best method for trace metal accumulation in streams to aid in understanding geochemical cycling.

Redox process catalysed by growing crystal-strengite, FePO4,2H2O, crystallizing from solution with iron(II) and hydroxylamine

NASA Astrophysics Data System (ADS)

Lundager Madsen, Hans Erik

2014-09-01

In an attempt to grow pure crystals of the iron(II) phosphate vivianite, Fe3(PO4)2,8H2O, from a solution of Mohr's salt, Fe(NH4)2(SO4)2,6H2O, added to a solution of ammonium phosphate, hydroxylammonium chloride, NH3OHCl, was added to the iron(II) stock solution to eliminate oxidation of iron(II) by oxygen from the air. However, the effect turned out to be the opposite of the expected: whereas hydroxylamine reduces iron(III) in bulk solution, it acted as a strong oxidant in the presence of growing iron phosphate crystals, causing the crystallization of the iron(III) phosphate strengite, FePO4,2H2O, as the only solid phase. Evidently the crystal surface catalyses oxidation of iron(II) by hydroxylamine. The usual composite kinetics of spiral growth and surface nucleation was found. The surface-nucleation part yielded edge free energy λ in the range 12-45 pJ/m, virtually independent of temperature and in the range typical for phosphates of divalent metals. The scatter of values for λ presumably arises from contributions from different crystal forms to the overall growth rate. The low mean value points to strong adsorption of iron(II), which is subsequently oxidized at the crystal surface, forming strengite. The state of the system did not tend to thermodynamic equilibrium, but to a metastable state, presumably controlled by the iron(II) rich surface layer of the crystal. In addition to crystal growth, it was possible to measure nucleation kinetics by light scattering (turbidimetry). A point of transition from heterogeneous to homogeneous nucleation was found, and from the results for the homogeneous domain a rather precise value of crystal surface free energy γ=55 mJ/m2 was found. This is a relatively low value as well, indicating that the redox process plays a role already at the nucleation stage.

Comparative reactivity of mismatched and unpaired bases in relation to their type and surroundings. Chemical cleavage of DNA mismatches in mutation detection analysis.

PubMed

Yakubovskaya, Marianna G; Belyakova, Anna A; Gasanova, Viktoria K; Belitsky, Gennady A; Dolinnaya, Nina G

2010-07-01

Systematic study of chemical reactivity of non-Watson-Crick base pairs depending on their type and microenvironment was performed on a model system that represents two sets of synthetic DNA duplexes with all types of mismatched and unmatched bases flanked by T.A or G.C pairs. Using comparative cleavage pattern analysis, we identified the main and additional target bases and performed quantitative study of the time course and efficacy of DNA modification caused by potassium permanganate or hydroxylamine. Potassium permanganate in combination with tetraethylammonium chloride was shown to induce DNA cleavage at all mismatched or bulged T residues, as well as at thymines of neighboring canonical pairs. Other mispaired (bulged) bases and thymine residues located on the second position from the mismatch site were not the targets for KMnO(4) attack. In contrast, hydroxylamine cleaved only heteroduplexes containing mismatched or unmatched C residues, and did not modify adjacent cytosines. However when G.C pairs flank bulged C residue, neighboring cytosines are also attacked by hydroxylamine due to defect migration. Chemical reactivity of target bases was shown to correlate strongly with the local disturbance of DNA double helix at mismatch or bulge site. With our model system, we were able to prove the absence of false-negative and false-positive results. Portion of heteroduplex reliably revealed in a mixture with corresponding homoduplex consists of 5% for bulge bases and "open" non-canonical pairs, and 10% for wobble base pairs giving minimal violations in DNA structure. This study provides a complete understanding of the principles of mutation detection methodology based on chemical cleavage of mismatches and clarifies the advantages and limitations of this approach in various biological and conformational studies of DNA. Copyright 2010 Elsevier Masson SAS. All rights reserved.

A proposed abiotic reaction scheme for hydroxylamine and monochloramine under chloramination relevant drinking water conditions.

PubMed

Wahman, David G; Speitel, Gerald E; Machavaram, Madhav V

2014-09-01

Drinking water monochloramine (NH2Cl) use may promote ammonia-oxidizing bacteria (AOB). AOB use (i) ammonia monooxygenase for biological ammonia (NH3) oxidation to hydroxylamine (NH2OH) and (ii) hydroxylamine oxidoreductase for NH2OH oxidation to nitrite. NH2Cl and NH2OH may react, providing AOB potential benefits and detriments. The NH2Cl/NH2OH reaction would benefit AOB by removing the disinfectant (NH2Cl) and releasing their growth substrate (NH3), but the NH2Cl/NH2OH reaction would also provide a possible additional inactivation mechanism besides direct NH2Cl reaction with cells. Because biological NH2OH oxidation supplies the electrons required for biological NH3 oxidation, the NH2Cl/NH2OH reaction provides a direct mechanism for NH2Cl to inhibit NH3 oxidation, starving the cell of reductant by preventing biological NH2OH oxidation. To investigate possible NH2Cl/NH2OH reaction implications on AOB, an understanding of the underlying abiotic reaction is first required. The present study conducted a detailed literature review and proposed an abiotic NH2Cl/NH2OH reaction scheme (RS) for chloramination relevant drinking water conditions (μM concentrations, air saturation, and pH 7-9). Next, RS literature based kinetics and end-products were evaluated experimentally between pHs 7.7 and 8.3, representing (i) the pH range for future experiments with AOB and (ii) mid-range pHs typically found in chloraminated drinking water. In addition, a (15)N stable isotope experiment was conducted to verify nitrous oxide and nitrogen gas production and their nitrogen source. Finally, the RS was slightly refined using the experimental data and an AQUASIM implemented kinetic model. A chloraminated drinking water relevant RS is proposed and provides the abiotic reaction foundation for future AOB biotic experiments. Published by Elsevier Ltd.

Nitroxide amide-BODIPY probe behavior in fibroblasts analyzed by advanced fluorescence microscopy.

PubMed

Liras, M; Simoncelli, S; Rivas-Aravena, A; García, O; Scaiano, J C; Alarcon, E I; Aspée, A

2016-04-26

A novel synthesized nitroxide amide-BODIPY prefluorescent probe was used to study cellular redox balance that modulates nitroxide/hydroxylamine ratio in cultured human fibroblasts. FLIM quantitatively differentiated between nitroxide states of the cytoplasm-localized probe imaged by TIRF, monitoring nitroxide depletion by hydrogen peroxide; eluding incorrect interpretation if only fluorescence intensity is considered.

Non-directed aromatic C–H amination: catalytic and mechanistic studies enabled by Pd catalyst and reagent design†

PubMed Central

Bandara, H. M. D.; Jin, D.; Mantell, M. A.; Field, K. D.; Wang, A.; Narayanan, R. P.; Deskins, N. A.; Emmert, M. H.

2016-01-01

This manuscript describes the systematic development of pyridine-type ligands, which promote the Pd catalyzed, non-directed amination of benzene in combination with novel, hydroxylamine-based electrophilic amination reagents. DFT calculations and mechanistic experiments provide insights into the factors influencing the arene C–H amination protocol. PMID:28066540

Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

EPA Science Inventory

For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag) and palladium (Pd), nanospheres, nanowires and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4) or hydroxylamine hydro...

Ancient DNA reveals that the genetic structure of the northern Han Chinese was shaped prior to 3,000 years ago.

PubMed

Zhao, Yong-Bin; Zhang, Ye; Zhang, Quan-Chao; Li, Hong-Jie; Cui, Ying-Qiu; Xu, Zhi; Jin, Li; Zhou, Hui; Zhu, Hong

2015-01-01

The Han Chinese are the largest ethnic group in the world, and their origins, development, and expansion are complex. Many genetic studies have shown that Han Chinese can be divided into two distinct groups: northern Han Chinese and southern Han Chinese. The genetic history of the southern Han Chinese has been well studied. However, the genetic history of the northern Han Chinese is still obscure. In order to gain insight into the genetic history of the northern Han Chinese, 89 human remains were sampled from the Hengbei site which is located in the Central Plain and dates back to a key transitional period during the rise of the Han Chinese (approximately 3,000 years ago). We used 64 authentic mtDNA data obtained in this study, 27 Y chromosome SNP data profiles from previously studied Hengbei samples, and genetic datasets of the current Chinese populations and two ancient northern Chinese populations to analyze the relationship between the ancient people of Hengbei and present-day northern Han Chinese. We used a wide range of population genetic analyses, including principal component analyses, shared mtDNA haplotype analyses, and geographic mapping of maternal genetic distances. The results show that the ancient people of Hengbei bore a strong genetic resemblance to present-day northern Han Chinese and were genetically distinct from other present-day Chinese populations and two ancient populations. These findings suggest that the genetic structure of northern Han Chinese was already shaped 3,000 years ago in the Central Plain area.

Ancient DNA Reveals That the Genetic Structure of the Northern Han Chinese Was Shaped Prior to 3,000 Years Ago

PubMed Central

Zhang, Quan-Chao; Li, Hong-Jie; Cui, Ying-Qiu; Xu, Zhi; Jin, Li; Zhou, Hui; Zhu, Hong

2015-01-01

The Han Chinese are the largest ethnic group in the world, and their origins, development, and expansion are complex. Many genetic studies have shown that Han Chinese can be divided into two distinct groups: northern Han Chinese and southern Han Chinese. The genetic history of the southern Han Chinese has been well studied. However, the genetic history of the northern Han Chinese is still obscure. In order to gain insight into the genetic history of the northern Han Chinese, 89 human remains were sampled from the Hengbei site which is located in the Central Plain and dates back to a key transitional period during the rise of the Han Chinese (approximately 3,000 years ago). We used 64 authentic mtDNA data obtained in this study, 27 Y chromosome SNP data profiles from previously studied Hengbei samples, and genetic datasets of the current Chinese populations and two ancient northern Chinese populations to analyze the relationship between the ancient people of Hengbei and present-day northern Han Chinese. We used a wide range of population genetic analyses, including principal component analyses, shared mtDNA haplotype analyses, and geographic mapping of maternal genetic distances. The results show that the ancient people of Hengbei bore a strong genetic resemblance to present-day northern Han Chinese and were genetically distinct from other present-day Chinese populations and two ancient populations. These findings suggest that the genetic structure of northern Han Chinese was already shaped 3,000 years ago in the Central Plain area. PMID:25938511

Magnetic nanoparticle-mediated isolation of functional bacteria in a complex microbial community

PubMed Central

Zhang, Dayi; Berry, James P; Zhu, Di; Wang, Yun; Chen, Yin; Jiang, Bo; Huang, Shi; Langford, Harry; Li, Guanghe; Davison, Paul A; Xu, Jian; Aries, Eric; Huang, Wei E

2015-01-01

Although uncultured microorganisms have important roles in ecosystems, their ecophysiology in situ remains elusive owing to the difficulty of obtaining live cells from their natural habitats. In this study, we employed a novel magnetic nanoparticle-mediated isolation (MMI) method to recover metabolically active cells of a group of previously uncultured phenol degraders, Burkholderiales spp., from coking plant wastewater biosludge; five other culturable phenol degraders—Rhodococcus sp., Chryseobacterium sp. and three different Pseudomonas spp.—were also isolated from the same biosludge using traditional methods. The kinetics of phenol degradation by MMI-recovered cells (MRCs) was similar to that of the original sludge. Stable isotope probing (SIP) and pyrosequencing of the 16S rRNA from the ‘heavy' DNA (13C-DNA) fractions indicated that Burkholderiales spp. were the key phenol degraders in situ in the biosludge, consistent with the results of MRCs. Single-cell Raman micro-spectroscopy was applied to probe individual bacteria in the MRCs obtained from the SIP experiment and showed that 79% of them were fully 13C-labelled. Biolog assays on the MRCs revealed the impact of various carbon and nitrogen substrates on the efficiency of phenol degradation in the wastewater treatment plant biosludge. Specifically, hydroxylamine, a metabolite of ammonia oxidisation, but not nitrite, nitrate or ammonia, inhibited phenol degradation in the biosludge. Our results provided a novel insight into the occasional abrupt failure events that occur in the wastewater treatment plant. This study demonstrated that MMI is a powerful tool to recover live and functional cells in situ from a complex microbial community to enable further characterisation of their physiology. PMID:25191996

Spatial Variations in N2O Concentration and Isotopomer Composition off the Peru Coast

NASA Astrophysics Data System (ADS)

Bourbonnais, A.; Letscher, R. T.; Kock, A.; Bange, H. W.; Altabet, M. A.

2016-02-01

Nitrous oxide (N2O) is a potent greenhouse gas and stratospheric ozone depleting substance. The ocean is an important source of N2O to the atmosphere, accounting for up to about 30% of total emissions. However, the factors controlling N2O production and consumption in oceanic environments are still not understood nor constrained. N2O is a by-product of aerobic nitrification, and is formed by two different pathways: 1) the decomposition of hydroxylamine, an intermediate during ammonium oxidation to nitrite, or 2) the reduction of nitrite to N2O (nitrifier-denitrification). N2O is also an intermediate during denitrification under anoxic conditions. In this study, we measured N2O concentrations and isotopomer ratios, as well as O2, nutrient and biogenic N2 concentrations and the isotopic compositions of nitrate, nitrite and biogenic N2 at several coastal stations during two cruises off the Peru coast (6-14°S, 75-81°W) in December 2012 and January 2013. [N2O] varied from below equilibrium values in the OMZ to up to 238 nmol L-1 at 11 m depth at one of the shallowest stations. The isotopic composition of N2O (bulk δ15N: -5 to 30‰, δ18O: 41 to 95‰, and Site Preference: -3 to 65‰) also varied widely, with important differences between stations. Our results show a strong spatial heterogeneity in the mechanisms controlling N2O production and consumption in coastal upwelling regions, which should be taken into account in oceanic N2O models. We will discuss the contributions from different N2O production processes responsible for the observed extreme N2O accumulations.

Adaptations to Submarine Hydrothermal Environments Exemplified by the Genome of Nautilia profundicola

PubMed Central

Campbell, Barbara J.; Smith, Julie L.; Hanson, Thomas E.; Klotz, Martin G.; Stein, Lisa Y.; Lee, Charles K.; Wu, Dongying; Robinson, Jeffrey M.; Khouri, Hoda M.; Eisen, Jonathan A.; Cary, S. Craig

2009-01-01

Submarine hydrothermal vents are model systems for the Archaean Earth environment, and some sites maintain conditions that may have favored the formation and evolution of cellular life. Vents are typified by rapid fluctuations in temperature and redox potential that impose a strong selective pressure on resident microbial communities. Nautilia profundicola strain Am-H is a moderately thermophilic, deeply-branching Epsilonproteobacterium found free-living at hydrothermal vents and is a member of the microbial mass on the dorsal surface of vent polychaete, Alvinella pompejana. Analysis of the 1.7-Mbp genome of N. profundicola uncovered adaptations to the vent environment—some unique and some shared with other Epsilonproteobacterial genomes. The major findings included: (1) a diverse suite of hydrogenases coupled to a relatively simple electron transport chain, (2) numerous stress response systems, (3) a novel predicted nitrate assimilation pathway with hydroxylamine as a key intermediate, and (4) a gene (rgy) encoding the hallmark protein for hyperthermophilic growth, reverse gyrase. Additional experiments indicated that expression of rgy in strain Am-H was induced over 100-fold with a 20°C increase above the optimal growth temperature of this bacterium and that closely related rgy genes are present and expressed in bacterial communities residing in geographically distinct thermophilic environments. N. profundicola, therefore, is a model Epsilonproteobacterium that contains all the genes necessary for life in the extreme conditions widely believed to reflect those in the Archaean biosphere—anaerobic, sulfur, H2- and CO2-rich, with fluctuating redox potentials and temperatures. In addition, reverse gyrase appears to be an important and common adaptation for mesophiles and moderate thermophiles that inhabit ecological niches characterized by rapid and frequent temperature fluctuations and, as such, can no longer be considered a unique feature of hyperthermophiles. PMID:19197347

Photometric microdetermination of malathion

USGS Publications Warehouse

Kallman, B.J.

1962-01-01

Carboxylic esters and lactones react with alkaline hydroxylamine to yield hydroxamates; these in acidic solution form colored iron(III) complexes. A photometric determination of such esters and lactones is thus permitted and has been extensively applied ( I-6). Hestrin ( 3) utilized this method for the microdetermination of acetylcholine and his procedure is much used for the in vitro study of cholinesterase activity and inhibition (4-6).

PEGylation and Dimerization of Expressed Proteins under Near Equimolar Conditions with Potassium 2-Pyridyl Acyltrifluoroborates

PubMed Central

2018-01-01

The covalent conjugation of large, functionalized molecules remains a frontier in synthetic chemistry, as it requires rapid, chemoselective reactions. The potassium acyltrifluoroborate (KAT)–hydroxylamine amide-forming ligation shows promise for conjugations of biomolecules under aqueous, acidic conditions, but the variants reported to date are not suited to ligations at micromolar concentrations. We now report that 2-pyridyl KATs display significantly enhanced ligation kinetics over their aryl counterparts. Following their facile, one-step incorporation onto the termini of polyethylene glycol (PEG) chains, we show that 2-pyridyl KATs can be applied to the construction of protein–polymer conjugates in excellent (>95%) yield. Four distinct expressed, folded proteins equipped with a hydroxylamine could be PEGylated with 2–20 kDa 2-pyridyl mPEG KATs in high yield and with near-equimolar amounts of coupling partners. Furthermore, the use of a bis 2-pyridyl PEG KAT enables the covalent homodimerization of proteins with good conversion. The 2-pyridyl KAT ligation offers an effective alternative to conventional protein–polymer conjugation by operating under aqueous acidic conditions well suited for the handling of folded proteins. PMID:29532019

Enhancement of Fenton oxidation for removing organic matter from hypersaline solution by accelerating ferric system with hydroxylamine hydrochloride and benzoquinone.

PubMed

Peng, Siwei; Zhang, Weijun; He, Jie; Yang, Xiaofang; Wang, Dongsheng; Zeng, Guisheng

2016-03-01

Fenton oxidation is generally inhibited in the presence of a high concentration of chloride ions. This study investigated the feasibility of using benzoquinone (BQ) and hydroxylamine hydrochloride (HA) as Fenton enhancers for the removal of glycerin from saline water under ambient temperature by accelerating the ferric system. It was found that organics removal was not obviously affected by chloride ions of low concentration (less than 0.1mol/L), while the mineralization rate was strongly inhibited in the presence of a large amount of chloride ions. In addition, ferric hydrolysis-precipitation was significantly alleviated in the presence of HA and BQ, and HA was more effective in reducing ferric ions into ferrous ions than HA, while the H2O2 decomposition rate was higher in the BQ-Fenton system. Electron spin resonance analysis revealed that OH production was reduced in high salinity conditions, while it was enhanced after the addition of HA and BQ (especially HA). This study provided a possible solution to control and alleviate the inhibitory effect of chloride ions on the Fenton process for organics removal. Copyright © 2015. Published by Elsevier B.V.

Protein chemical synthesis by α-ketoacid-hydroxylamine ligation.

PubMed

Harmand, Thibault J; Murar, Claudia E; Bode, Jeffrey W

2016-06-01

Total chemical synthesis of proteins allows researchers to custom design proteins without the complex molecular biology that is required to insert non-natural amino acids or the biocontamination that arises from methods relying on overexpression in cells. We describe a detailed procedure for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA ligation), using (S)-5-oxaproline (Opr) as a key building block. This protocol comprises two main parts: (i) the synthesis of peptide fragments by standard fluorenylmethoxycarbonyl (Fmoc) chemistry and (ii) the KAHA ligation between fragments containing Opr and a C-terminal peptide α-ketoacid. This procedure provides an alternative to native chemical ligation (NCL) that could be valuable for the synthesis of proteins, particularly targets that do not contain cysteine residues. The ligation conditions-acidic DMSO/H2O or N-methyl-2-pyrrolidinone (NMP)/H2O-are ideally suited for solubilizing peptide segments, including many hydrophobic examples. The utility and efficiency of the protocol is demonstrated by the total chemical synthesis of the mature betatrophin (also called ANGPTL8), a 177-residue protein that contains no cysteine residues. With this protocol, the total synthesis of the betatrophin protein has been achieved in around 35 working days on a multimilligram scale.

Production of Hydroxyl Radical via the Activation of Hydrogen Peroxide by Hydroxylamine.

PubMed

Chen, Liwei; Li, Xuchun; Zhang, Jing; Fang, Jingyun; Huang, Yanmin; Wang, Ping; Ma, Jun

2015-09-01

The production of the hydroxyl radical (HO·) is important in environmental chemistry. This study reports a new source of HO· generated solely from hydrogen peroxide (H2O2) activated by hydroxylamine (HA). Electron paramagnetic resonance analysis and the oxidation of a HO· probe, benzoic acid, were used to confirm the production of HO·. The production of HO· increased with increasing concentrations of either HA or H2O2 as well as decreasing pH. The second-order rate constant for the reaction was (2.2 ± 0.2) × 10(-4) M(-1) s(-1). HO· was probably produced in two steps: the activation of H2O2 by protonated HA and then reaction between the H2O2 and the intermediate protonated aminoxyl radical generated in the first step. Such a two-step oxidation can possibly be ascribed to the ionizable hydroxyl moiety in the molecular structure of HA, as is suggested by comparing the reactivity of a series of HA derivatives in HO· production. The results shed light on a previously unknown source of HO· formation, which broadens the understanding of its role in environmental processes.

Oxidation of DNA bases, deoxyribonucleosides and homopolymers by peroxyl radicals.

PubMed Central

Simandan, T; Sun, J; Dix, T A

1998-01-01

DNA base oxidation is considered to be a key event associated with disease initiation and progression in humans. Peroxyl radicals (ROO. ) are important oxidants found in cells whose ability to react with the DNA bases has not been characterized extensively. In this paper, the products resulting from ROO. oxidation of the DNA bases are determined by gas chromatography/MS in comparison with authentic standards. ROO. radicals oxidize adenine and guanine to their 8-hydroxy derivatives, which are considered biomarkers of hydroxyl radical (HO.) oxidations in cells. ROO. radicals also oxidize adenine to its hydroxylamine, a previously unidentified product. ROO. radicals oxidize cytosine and thymine to the monohydroxy and dihydroxy derivatives that are formed by oxidative damage in cells. Identical ROO. oxidation profiles are observed for each base when exposed as deoxyribonucleosides, monohomopolymers and base-paired dihomopolymers. These results have significance for the development, utilization and interpretation of DNA base-derived biomarkers of oxidative damage associated with disease initiation and propagation, and support the idea that the mutagenic potential of N-oxidized bases, when generated in cellular DNA, will require careful evaluation. Adenine hydroxylamine is proposed as a specific molecular probe for the activity of ROO. in cellular systems. PMID:9761719

Identification of key nitrous oxide production pathways in aerobic partial nitrifying granules.

PubMed

Ishii, Satoshi; Song, Yanjun; Rathnayake, Lashitha; Tumendelger, Azzaya; Satoh, Hisashi; Toyoda, Sakae; Yoshida, Naohiro; Okabe, Satoshi

2014-10-01

The identification of the key nitrous oxide (N2O) production pathways is important to establish a strategy to mitigate N2O emission. In this study, we combined real-time gas-monitoring analysis, (15)N stable isotope analysis, denitrification functional gene transcriptome analysis and microscale N2O concentration measurements to identify the main N2O producers in a partial nitrification (PN) aerobic granule reactor, which was fed with ammonium and acetate. Our results suggest that heterotrophic denitrification was the main contributor to N2O production in our PN aerobic granule reactor. The heterotrophic denitrifiers were probably related to Rhodocyclales bacteria, although different types of bacteria were active in the initial and latter stages of the PN reaction cycles, most likely in response to the presence of acetate. Hydroxylamine oxidation and nitrifier denitrification occurred, but their contribution to N2O emission was relatively small (20-30%) compared with heterotrophic denitrification. Our approach can be useful to quantitatively examine the relative contributions of the three pathways (hydroxylamine oxidation, nitrifier denitrification and heterotrophic denitrification) to N2O emission in mixed microbial populations. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Action of inhibitors on hydrogenase in Azotobacter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, J.B.; Wilson, P.W.

1943-01-01

The inhibitors usually associated with the activity of the cytochrome oxidase system - cyanide and carbon monoxide - are also effective in reducing the oxidation of H/sub 2/ by intact cells of Azotobacter vinclandii. The hydrogenase system is more sensitive to CO than is the respiratory system. Oxidation of a carbon source and of hydrogen by Azotobacter cells is inhibited in a quantitatively different manner by the following compounds: sodium azide, hydroxylamine, sodium iodoacetate, and sodium fluoride. In every case, a concentration range which is definitely inhibitory for respiration has little or no effect on the hydrogenase activity. The differentialmore » inhibition by hydroxylamine explains certain observations in the literature which have been erroneously interpreted as demonstrating a specific inhibition by NH/sub 2/OH of biological nitrogen fixation. This supposed demonstration has been offered as support for the hypothesis that NH/sub 2/OH is an intermediate in the fixation reaction. The differential inhibitors can be used for detection of hydrogenase in cultures possessing a high endogenous respiration. The method is illustrated by an experiment with root nodule bacteria from pea and cowpea nodules. No hydrogenase was found in either. 8 references, 4 figures, 4 tables.« less

Kinetics, mechanisms, and influencing factors on the treatment of haloacetonitriles (HANs) in water by two household heating devices.

PubMed

Shi, Wendong; Wang, Lei; Chen, Baiyang

2017-04-01

Haloacetonitriles (HANs) are a group of nitrogenous disinfection by-products (DBPs) commonly found in treated water with potential carcinogenic, cytotoxic, and genotoxic risks. In order to control HANs and understand their real intake levels by people via drinking water, this study evaluated a list of structural, operational, and environmental factors affecting the treatment of HANs by two domestic heating devices, i.e., an electric boiler and a microwave oven. Results show that the concentrations of HANs decreased exponentially over time with increasing temperature, water turbulence, and bubbles, and the phenomena were most likely due to a combined effect of volatilization and hydrolysis. Among HANs, the lability increased with increasing halogenation degrees (i.e., tri- > di- > mono- HANs) yet decreasing halogen molecular weights (i.e., Cl- > Br- > I- HANs); such trends were well captured by quantitative structure activity relationship models (R 2  = 0.99). Operational factors played critical roles in controlling HANs too, including the rate of heating, water volume, water temperature at time of pouring, cooling method, and capping condition, suggesting that people could benefit from proper handling methods and procedures. In addition, HANs added to tap water exhibited higher removals than those added to ultrapure water, probably because of the presence of free chlorine in tap water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Drosophila GPCR Han is a receptor for the circadian clock neuropeptide PDF.

PubMed

Hyun, Seogang; Lee, Youngseok; Hong, Sung-Tae; Bang, Sunhoe; Paik, Donggi; Kang, Jongkyun; Shin, Jinwhan; Lee, Jaejung; Jeon, Keunhye; Hwang, Seungyoon; Bae, Eunkyung; Kim, Jaeseob

2005-10-20

The pigment-dispersing factor (PDF) is a neuropeptide controlling circadian behavioral rhythms in Drosophila, but its receptor is not yet known. From a large-scale temperature preference behavior screen in Drosophila, we isolated a P insertion mutant that preferred different temperatures during the day and night. This mutation, which we named han, reduced the transcript level of CG13758. We found that Han was expressed specifically in 13 pairs of circadian clock neurons in the adult brain. han null flies showed arrhythmic circadian behavior in constant darkness. The behavioral characteristics of han null mutants were similar to those of pdf null mutants. We also found that PDF binds specifically to S2 cells expressing Han, which results in the elevation of cAMP synthesis. Therefore, we herein propose that Han is a PDF receptor regulating circadian behavioral rhythm through coordination of activities of clock neurons.

Reactions of in situ generated N-Boc nitrones with aromatic and heteroaromatic grignard reagents: application to the synthesis of zileuton.

PubMed

Guinchard, Xavier; Denis, Jean-Noël

2008-03-07

A new class of alpha-aromatic-N-hydroxylamines has been prepared by reaction of tert-butyl (phenylsulfonyl)alkyl-N-hydroxycarbamates with aromatic and heteroaromatic Grignard reagents. Reactions proceed via a base-assisted elimination of the phenylsulfonyl group leading to N-Boc nitrones. This methodology has been applied to the synthesis of zileuton.

OZONATION BY-PRODUCTS 2. IMPROVEMENT OF AN AQUEOUS- PHASE DERIVITIZATION METHOD FOR THE DETECTION OF FORMALDEHYDE AND OTHER CARBONYL COMPOUNDS FORMED BY THE OZONATION OF DRINKING WATER

EPA Science Inventory

A method for the determination of low molecular weight aldehydes in water using aqueous-phase derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride has been improved by the use of high-resolution capillary GC. Detection limits with GC/ECD and GC/MS with ...

Comparison of maternal and newborn outcomes of Tibetan and Han Chinese delivering in Lhasa, Tibet

PubMed Central

Miller, Suellen; Tudor, Carrie; Thorsten, Vanessa; Nyima; Sonam; Droyoung; Wright, Linda; Varner, Michael

2009-01-01

Aim To compare maternal and neonatal outcomes of Tibetan and Han Chinese women delivering vaginally at high altitude (3650 meters) in Lhasa, Tibet Autonomous Region, People’s Republic of China. Method Comparative analysis of data from a prospective observational study of Tibetan (n = 938) and Han Chinese (n = 146) women delivering at three hospitals between January 2004 and May 2005. Results Han Chinese women had higher rates of pre-eclampsia/gestational hypertension than Tibetan women, (10.3% vs 5.9%, P = 0.04). There was no difference in rates of postpartum hemorrhage between Tibetan and Han women (12.8% vs 17.1%, P = 0.15). Han newborns weighed significantly less than Tibetan newborns (P < 0.01), and were twice as likely to be small for gestational age, (24.5% vs 11.6%, P < 0.01). Tibetan newborns were less likely to have poor neonatal outcomes than Han newborns (P < 0.01). Conclusion In high altitude deliveries in Tibet, adverse outcomes were significantly more common among Han Chinese. PMID:19012697

[Textual research on the time of completion of XU Shuwei' books on exo-pathogenic cold diseases].

PubMed

Lu, Mingxin

2015-11-01

Shang han bai zheng ge (Poets of Syndromes of Exo-pathogenic Cold Disease), Shang han fa wei lun (Discourse on Elucidation of Exo-pathogenic Cold Disease), Shang han jiu shi lun (90 Discourses on Exo-pathogenic Cold Disease) were the three extant books on exo-pathogenic cold disease written by Xu Shuwei among his other works of its kind. Although there were carved editions of the Yuan and Ming Dynasties, these books were gradually paid attention for citations by other physicians till the Qing Dynasty. Through comparison of its texts, it can be found that the title of Shang han bai zheng ge was mentioned in his other medical works. While Shang han fa wei lun and Shang han jiu shi lun contained some overlapping contents, some even carrying concept contradictory to each other. According to historical materials, Xu Shuwei began to write the above-mentioned 3 books in the Northern Song Dynasty. In the several early years of the Southern Song Dynasty after crossing the Yangtze River, he collected the remained manuscripts and continued to write. Among them, Shang han bai zheng ge was completed first, followed by Shang han fa wei lun, with Shang han jiu shi lun came as the last.

[Distribution of MICA microsatellite in 13 population groups of China].

PubMed

Ban, G H; Chu, J Y; Xu, S B; Yang, Z Q; Qian, Y P; Yu, J K; Na, J B; Liu, X J; Zhang, S Z

2001-01-01

The genetic data of MICA microsatellite were obtained by genotyping 577 samples in 13 population groups of China, which are Han-YN, Han-GD, Han-SD, Bai, Dai, Lahu, Li, Naxi, Sala, She, Tu, Wa and Zang-YN, with genescan. Five alleles have been observed in the population groups, which are A4, A5, A5.1, A6 and A9. A5 allele is the most frequent in all population groups except Lahu and Li, while the most frequent allele for Lahu and Li is A5. 1 and A4 respectively. The second most frequent allele is the A5.1 in Han-YN, Han-SD, Dai, Naxi, Sala, She, and Wa. The lest frequent allele for Han-YN, Han-GD, Lahu, Naxi, She, Wa is the A6 which is not observed in Li. A4 allele is the lest frequent in Han-SD, Bai, Dai, Sala, Tu, Zang-YN. The results show that the distribution of MICA microsatellite is different in these population groups, and the polymorphism information contents (PIC) of this microsatellite is high. It is a potential useful marker in the study of human origin and migration, personal identification, gene mapping and location, and disease diagnosis.

Implicit Trust between the Uyghur and the Han in Xinjiang, China

PubMed Central

Li, Xueting; Fang, Huizhen; Yang, Shengmin; Liu, Jia

2013-01-01

Trust is a vital lubricant that increases the sense of security in social interactions. In this study, we investigated the intergroup trust between the Uyghur and the Han, the two largest ethnic groups in Xinjiang, China, with a Go/No-Go Association Task. Specifically, we instructed Uyghur and Han participants to respond to ethnic faces (Uyghur vs. Han) and trust/distrust words and measured the strength of the automatic associations between the faces and words for both in-group and out-group pairs. As expected, both ethnic groups showed implicit in-group trust and out-group distrust, but the Han group demonstrated stronger in-group trust and out-group distrust toward the Uyghur than the Uyghur group toward the Han. However, the magnitude of distrust of the Han toward the Uyghur was small to medium as compared with that reported by other intergroup relationship research. In addition, participant geographic location was associated with out-group distrust. These findings offer implications for developing effective strategies to encourage trust between conflicting groups. PMID:23977155

Analysis of Hydrodynamic (Landau) Instability in Liquid-Propellant Combustion at Normal and Reduced Gravity

NASA Technical Reports Server (NTRS)

Margolis, Stephen B.

1997-01-01

The burning of liquid propellants is a fundamental combustion problem that is applicable to various types of propulsion and energetic systems. The deflagration process is often rather complex, with vaporization and pyrolysis occurring at the liquid/gas interface and distributed combustion occurring either in the gas phase or in a spray. Nonetheless, there are realistic limiting cases in which combustion may be approximated by an overall reaction at the liquid/gas interface. In one such limit, the gas flame occurs under near-breakaway conditions, exerting little thermal or hydrodynamic influence on the burning propellant. In another such limit, distributed combustion occurs in an intrusive regime, the reaction zone lying closer to the liquid/gas interface than the length scale of any disturbance of interest. Finally, the liquid propellant may simply undergo exothermic decomposition at the surface without any significant distributed combustion, such as appears to occur in some types of HydroxylAmmonium Nitrate (HAN)-based liquid propellants at low pressures. Such limiting models have recently been formulated,thereby significantly generalizing earlier classical models that were originally introduced to study the hydrodynamic stability of a reactive liquid/gas interface. In all of these investigations, gravity appears explicitly and plays a significant role, along with surface tension, viscosity, and, in the more recent models, certain reaction-rate parameters associated with the pressure and temperature sensitivities of the reaction itself. In particular, these parameters determine the stability of the deflagration with respect to not only classical hydrodynamic disturbances, but also with respect to reactive/diffusive influences as well. Indeed, the inverse Froude number, representing the ratio of buoyant to inertial forces, appears explicitly in all of these models, and consequently, in the dispersion relation that determines the neutral stability boundaries beyond which steady, planar burning is unstable to nonsteady, and/or nonplanar (cellular) modes of burning. These instabilities thus lead to a number of interesting phenomena, such as the sloshing type of waves that have been observed in mixtures of HAN and TriEthanolAmmonium Nitrate (TEAN) with water. Although the Froude number was treated as an O(1) quantity in these studies, the limit of small inverse Froude number corresponding to the microgravity regime is increasingly of interest and can be treated explicitly, leading to various limiting forms of the models, the neutral stability boundaries, and, ultimately, the evolution equations that govern the nonlinear dynamics of the propagating reaction front. In the present work, we formally exploit this limiting parameter regime to compare some of the features of hydrodynamic instability of liquid-propellant combustion at reduced gravity with the same phenomenon at normal gravity.

Studies on chemical evolution using carbon suboxide

NASA Technical Reports Server (NTRS)

Yanagawa, H.; Egami, F.

1980-01-01

It was learned that when carbon suboxide polymers react with hydroxylamine in modified sea water the amino acids glycine and lysine are produced and that they react with urea to produce nucleic acid-like substances. These results lead to the supposition that it is possible that carbon suboxide polymers may have accumulated in the primeval sea some three or more billion years ago and were transformed into the procursors of living molecules.

Accidental mold/termite testing of high density fiberboard (HDF) treated with borates and N’N-naphthaloylhydroxylamine (NHA)

Treesearch

S. Nami Kartal; Harold H. Burdsall; Frederick Green

2003-01-01

High density fibreboard (HDF) was made from beech and pine furnish (50:50) and treated with boric acid (0.1-3%), borax (0.1-3%) or N'-N-(1,8- naphthalyl) hydroxylamine (NHA) (0.1-1%) prior to gluing with urea formaldehyde (UF) resin in order to determine resistance to Eastern subterranean termites ( Reticulitermes flavipes Kollar), the most economically important...

Theoretical characterization of stable eta1-N2O-, eta2-N2O-, eta1-N2-, and eta2-N2-bound species: intermediates in the addition reactions of nitrogen hydrides with the pentacyanonitrosylferrate(II) ion.

PubMed

Olabe, José A; Estiú, Guillermina L

2003-08-11

The addition of nitrogen hydrides (hydrazine, hydroxylamine, ammonia, azide) to the pentacyanonitrosylferrate(II) ion has been analyzed by means of density functional calculations, focusing on the identification of stable intermediates along the reaction paths. Initial reversible adduct formation and further decomposition lead to the eta(1)- and eta(2)-linkage isomers of N(2)O and N(2), depending on the nucleophile. The intermediates (adducts and gas-releasing precursors) have been characterized at the B3LYP/6-31G level of theory through the calculation of their structural and spectroscopic properties, modeling the solvent by means of a continuous approach. The eta(2)-N(2)O isomer is formed at an initial stage of adduct decompositions with the hydrazine and azide adducts. Further conversion to the eta(1)-N(2)O isomer is followed by Fe-N(2)O dissociation. Only the eta(1)-N(2)O isomer is predicted for the reaction with hydroxylamine, revealing a kinetically controlled N(2)O formation. eta(1)-N(2) and eta(2)-N(2) isomers are also predicted as stable species.

Novel Escherichia coli umuD′ Mutants: Structure-Function Insights into SOS Mutagenesis

PubMed Central

McLenigan, Mary; Peat, Thomas S.; Frank, Ekaterina G.; McDonald, John P.; Gonzalez, Martín; Levine, Arthur S.; Hendrickson, Wayne A.; Woodgate, Roger

1998-01-01

Although it has been 10 years since the discovery that the Escherichia coli UmuD protein undergoes a RecA-mediated cleavage reaction to generate mutagenically active UmuD′, the function of UmuD′ has yet to be determined. In an attempt to elucidate the role of UmuD′ in SOS mutagenesis, we have utilized a colorimetric papillation assay to screen for mutants of a hydroxylamine-treated, low-copy-number umuD′ plasmid that are unable to promote SOS-dependent spontaneous mutagenesis. Using such an approach, we have identified 14 independent umuD′ mutants. Analysis of these mutants revealed that two resulted from promoter changes which reduced the expression of wild-type UmuD′, three were nonsense mutations that resulted in a truncated UmuD′ protein, and the remaining nine were missense alterations. In addition to the hydroxylamine-generated mutants, we have subcloned the mutations found in three chromosomal umuD1, umuD44, and umuD77 alleles into umuD′. All 17 umuD′ mutants resulted in lower levels of SOS-dependent spontaneous mutagenesis but varied in the extent to which they promoted methyl methanesulfonate-induced mutagenesis. We have attempted to correlate these phenotypes with the potential effect of each mutation on the recently described structure of UmuD′. PMID:9721309

Association of the rs7395662 SNP in the MADD-FOLH1 and Several Environmental Factors with Serum Lipid Levels in the Mulao and Han Populations

PubMed Central

Huang, Ke-Ke; Yin, Rui-Xing; Zeng, Xiao-Na; Huang, Ping; Lin, Quan-Zhen; Wu, Jian; Guo, Tao; Wang, Wei; Yang, De-Zhai; Lin, Wei-Xiong

2013-01-01

Background: The rs7395662 single nucleotide polymorphism (SNP) in the MADD-FOLH1 has been associated with serum lipid traits, but the results are inconsistent in different populations. The present study was undertaken to investigate the association of rs7395662 SNP and several environmental factors with serum lipid levels in the Guangxi Mulao and Han populations. Method: A total of 721 subjects of Mulao and 727 subjects of Han Chinese were randomly selected from our previous stratified randomized samples. Genotyping of the SNP was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and confirmed by direct sequencing. Results: Serum apolipoprotein (Apo) B levels were higher in Mulao than in Han (P < 0.01). The allelic and genotypic frequencies in Han were different between males and females (P < 0.05 for each), but there was no difference between Mulao and Han or between Mulao males and females. The levels of low-density lipoprotein cholesterol (LDL-C) and ApoB in Mulao females were different among the genotypes (P < 0.05), the G allele carriers had higher LDL-C and ApoB levels than the G allele non-carriers. The levels of total cholesterol (TC), triglyceride (TG), LDL-C and ApoB in Han males and TC, TG and high-density lipoprotein cholesterol (HDL-C) in Han females were different among the genotypes (P < 0.05-0.01), the subjects with GG genotype in Han males had higher TC, TG, and ApoB and lower LDL-C levels than the subjects with AA or AG genotype, and the G allele carriers in Han females had lower TC and HDL-C levels than the G allele non-carriers. The levels of LDL-C and ApoB in Mulao females were correlated with the genotypes (P < 0.05 for each). The levels of HDL-C and ApoAI in Han males and HDL-C in Han females were correlated with genotypes (P < 0.05-0.001). Serum lipid parameters were also correlated with several environmental factors in both ethnic groups (P < 0.05-0.01). Conclusion: The association of rs7395662 SNP and serum lipid levels is different between the Mulao and Han populations, and between males and females in both ethnic groups. PMID:24046529

Population genetic data of the NGM SElect STR loci in Chinese Han population from Zhejiang region, China.

PubMed

Zhou, Anju; Wu, Weiwei; Liu, Qiuling; Wu, Yeda; Lu, Dejian

2013-03-01

Genetic variations of the 17 NGM SElect STR loci in Chinese Han samples from the Zhejiang region were analyzed. The results show that the NGM SElect is a highly genetic informative system in Zhejiang Han, and this population shows quite different genetic data from other major populations in the world with the exception of the Fujian Han.

Factor analysis and cluster analysis applied to assess the water quality of middle and lower Han River in Central China

NASA Astrophysics Data System (ADS)

Kuo, Yi-Ming; Liu, Wen-Wen

2015-04-01

The Han River basin is one of the most important industrial and grain production bases in the central China. A lot of factories and towns have been established along the river where large farmlands are located nearby. In the last few decades the water quality of the Han River, specifically in middle and lower reaches, has gradually declined. The agricultural nonpoint pollution and municipal and industrial point pollution significantly degrade the water quality of the Han River. Factor analysis can be applied to reduce the dimensionality of a data set consisting of a large number of inter-related variables. Cluster analysis can classify the samples according to their similar characters. In this study, factor analysis is used to identify major pollution indicators, and cluster analysis is employed to classify the samples based on the sample locations and hydrochemical variables. Water samples were collected from 12 sample sites collected from Xiangyang City (middle Han River) to Wuhan City (lower Han River). Correlations among 25 hydrochemical variables are statistically examined. The important pollutants are determined by factor analysis. A three-factor model is determined and explains over 85% of the total river water quality variation. Factor 1, including SS, Chl-a, TN and TP, can be considered as the nonpoint source pollution. Factor 2, including Cl-, Br-, SO42-, Ca2+, Mg2+, K+, Fe2+ and PO43-, can be treated as the industrial pollutant pollution. Factor 3, including F- and NO3-, reflects the influence of the groundwater or self-purification capability of the river water. The various land uses along the Han River correlate well with the pollution types. In addition, the result showed that the water quality of Han River deteriorated gradually from middle to lower Han River. Some tributaries have been seriously polluted and significantly influence the mainstream water quality of the Han River. Finally, the result showed that the nonpoint pollution and the point pollution both significantly influence water quality in the middle and lower Han River. This study provides an effective method for watershed management and pollution control in Han River.

Influence of the South-to-North Water Transfer and the Yangtze River Mitigation Projects on the water quality of Han River, China

NASA Astrophysics Data System (ADS)

Liu, W.; Kuo, Y. M.

2016-12-01

The Middle Route of China's South-to-North Water Transfer (MSNW) and Yangtze-Han River Water Diversion (YHWD) Projects have been operated since 2014, which may deteriorate water quality in Han River. The 11 water sampling sites distributed from the middle and down streams of Han River watershed were monitored monthly between July 2014 and December 2015. Factor analysis and cluster analysis were applied to investigate the major pollution types and main variables influencing water quality in Han River. The factor analysis distinguishes three main pollution types (agricultural nonpoint source, organic, and phosphorus point source pollution) affecting water quality of Han River. Cluster analysis classified all sampling sites into four groups and determined their pollution source for both Dry and Wet seasons. The sites located at central city receive point source pollution in both seasons. The water quality in downstream Han River (excluding central city sites) was influenced by nonpoint source pollution from Jianghan Plain. Variations of water qualities are associated with hydrological conditions varied from operations of engineering projects and seasonal variability especially in Dry season. Good water quality as Class III mainly occurred when flow rate is greater than 800 cms in Dry season. The low average flow rate below 583 cms will degrade water quality as Class V at almost all sites. Elevating the flow rate discharged from MSNW and YHWD Projects to Han River can avoid degrading water quality especially in low flow conditions and may decrease the probability of algal bloom occurrence in Han River. Increasing the flow rate from 400 cms to 700 cms in main Han River can obviously improve the water quality of Han River. The investigation of relationships between water quality and flow rate in both projects can provide management strategies of water quality for various flow conditions.

Neonatal Handling Increases Cardiovascular Reactivity to Contextual Fear Conditioning in Borderline Hypertensive Rats (BHR)

PubMed Central

Sanders, Brian J.; Knoepfler, Jonathan

2008-01-01

Much research has demonstrated that events occurring in early life can have a profound influence on future biobehavioral responses to stressful and emotion provoking situations. The purpose of these studies was to determine the effects of an early environmental manipulation, handling (HAN) on cardiovascular (CV) reactivity, freezing behavior and corticosterone (CORT) responses to contextual fear conditioning in the borderline hypertensive rat (BHR), which is susceptible to environmental stressors. HAN subjects were separated from the nest for 15 min/day on post-natal days 1–14, while non-handled (NON-HAN) controls remained in the home cage. Adult subjects were exposed to the contextual fear conditioning procedure and returned to the chamber 24 h later for a 10 min test period. HAN subjects displayed significantly more freezing behavior compared to NON-HAN(92%±2.2 vs 80.7%±5.7, p < .05). Although resting MAP did not differ between groups, HAN subjects had increased MAP reactivity when re-exposed to the chamber. In addition, HAN subjects had significantly lower CORT levels at the end of the 10 min test period (174.2±9 ng/ml vs 237.2±12.9 ng/ml, p < .05). In the second experiment, CORT responses to 60 min of restraint stress and recovery following return to the home cage were assessed in separate groups of HAN and NON-HAN subjects. HAN subjects showed reduced CORT levels in response to acute restraint stress. These results indicate that neonatal handling can modulate biobehavioral responses to contextual fear conditioning in BHR and may suggest a useful model with which to study emotionality and susceptibility to CV disease. PMID:18538802

Using Pure Cultures to Define the Site Preference of Nitrous Oxide Produced by Microbial Nitrification and Denitrification

NASA Astrophysics Data System (ADS)

Sutka, R. L.; Breznak, J. A.; Ostrom, N. E.; Ostrom, P. H.; Gandhi, H.

2004-12-01

Defining the site preference of nitrous oxide (N2O) produced in pure culture studies is crucial to interpreting field data. We have previously demonstrated that the intramolecular distribution of nitrogen isotopes (isotopomers) can be used to differentiate N2O produced by nitrifier denitrification and nitrification in cultures of Nitrosomonas europaea. Here, we have expanded on our initial results and evaluated the isotopomeric composition of N2O produced during nitrification and nitrifier denitrification with cultures of Nitrosospira multiformis. In addition, we have analyzed N2O produced during methanotrophic nitrification, denitrification, and fungal denitrification. To evaluate N2O production during nitrification and nitrifier denitrification, we compared the site preference of N2O formed as a result of nitrite reduction and hydroxylamine oxidation with Nitrosomonas europaea and Nitrosospira multiformis. The average site preference of N2O produced by hydroxylamine oxidation was similar for Nitrosomonas europaea (33.0 ± 3.5 ‰ ) and Nitrosospira multiformis (33.1 ± 4.2 ‰ ). Nitrous oxide produced by nitrifier-denitrification by Nitrosomonas europaea and Nitrosospira multiformis had a similar site preference of - 1.4 ± 4.4 ‰ and - 1.1 ± 2.6 ‰ respectively. The results indicate that it is possible to differentiate between N2O produced by nitrite reduction and hydroxylamine oxidation by ammonia oxidizing bacteria. Methanotrophic nitrification was evaluated by analyzing the N2O produced during hydroxylamine oxidation in concentrated cell suspensions of two methane oxidizing bacteria. The site preference of N2O produced by the two methane oxidizers, Methylococcus capsulatus Bath and Methylosinus trichosporium was 31.8 ± 4.7 ‰ and 33.0 ± 4.5 ‰ respectively. The results indicate that a site preference of 33 ‰ is applicable for nitrification regardless of whether a methane oxidizer or ammonia oxidizer is involved in the reaction. To determine the site preference of N2O produced during denitrification we used concentrated cell suspensions of two organisms (Pseudomonas chlororaphis and Pseudomonas aureofaciens) that lack N2O reductase. The site preference of N2O produced during nitrite reduction was similar for P. chlororaphis (0.3 ± 2.7 ‰ ) and P. aureofaciens (- 0.3 ± 1.7 ‰ ). The results indicate that the site preference of N2O produced during nitrite reduction is 0 ‰ regardless of whether the organism is a denitrifier or nitrifier. Fungal denitrification was investigated using pure cultures of Fusarium oxysporum and Cylindrocarpon tonkinense. The site preference of N2O produced during nitrite reduction was similar for the cultures with an average site preference of 34.7 ± 2.2 ‰ for Fusarium oxysporum and 29.7 ± 1.7 ‰ for Cylindrocarpon tonkinense. The data indicate that fungal denitrification and bacterial denitrification can be distinguished based on site preference. The results from all of the pure culture studies indicate that isotopomers can be used to apportion bacterial nitrification and denitrification and in field studies.

HANABA TARANU regulates the shoot apical meristem and leaf development in cucumber (Cucumis sativus L.)

PubMed Central

Ding, Lian; Yan, Shuangshuang; Jiang, Li; Liu, Meiling; Zhang, Juan; Zhao, Jianyu; Zhao, Wensheng; Han, Ying-yan; Wang, Qian; Zhang, Xiaolan

2015-01-01

The shoot apical meristem (SAM) is essential for continuous organogenesis in higher plants, while the leaf is the primary source organ and the leaf shape directly affects the efficiency of photosynthesis. HANABA TARANU (HAN) encodes a GATA3-type transcription factor that functions in floral organ development, SAM organization, and embryo development in Arabidopsis, but is involved in suppressing bract outgrowth and promoting branching in grass species. Here the function of the HAN homologue CsHAN1 was characterized in cucumber, an important vegetable with great agricultural and economic value. CsHAN1 is predominantly expressed at the junction of the SAM and the stem, and can partially rescue the han-2 floral organ phenotype in Arabidopsis. Overexpression and RNAi of CsHAN1 transgenic cucumber resulted in retarded growth early after embryogenesis and produced highly lobed leaves. Further, it was found that CsHAN1 may regulate SAM development through regulating the WUSCHEL (WUS) and SHOOT MERISTEMLESS (STM) pathways, and mediate leaf development through a complicated gene regulatory network in cucumber. PMID:26320238

Disparities in Hypertension Prevalence, Awareness, Treatment and Control between Bouyei and Han: Results from a Bi-Ethnic Health Survey in Developing Regions from South China.

PubMed

Dong, Fen; Wang, Dingming; Pan, Li; Yu, Yangwen; Wang, Ke; Li, Ling; Wang, Li; Liu, Tao; Zeng, Xianjia; Sun, Liangxian; Zhu, Guangjin; Feng, Kui; Zhang, Biao; Xu, Ke; Pang, Xinglong; Chen, Ting; Pan, Hui; Ma, Jin; Zhong, Yong; Ping, Bo; Shan, Guangliang

2016-02-19

Hypertension is highly prevalent in low-income population. This study aims to investigate ethnic disparities in hypertension and identify modifiable factors related to its occurrence and control in developing regions in South China. Blood pressure was measured in the Bouyei and Han populations during a community-based health survey in Guizhou, 2012. A multistage stratified sampling method was adopted to recruit Bouyei and Han aged from 20 to 80 years. Taking mixed effects into consideration, multilevel logistic models with random intercept were used for data analysis. The prevalence rates of hypertension were 35.3% for the Bouyei and 33.7% for the Han. Among the hypertensive participants, 30.1% of the Bouyei and 40.2% of the Han were aware of their hypertensive conditions, 19.7% of the Bouyei and 31.1% of the Han were receiving treatment, and only 3.6% of the Bouyei and 9.9% of the Han had their blood pressure under control. Age-sex standardized rates of awareness, treatment, and control were consistently lower in the Bouyei than the Han. Such ethnic disparities were more evident in the elderly population. Avoidance of excessive alcohol consumption and better education were favorable lifestyle for reduction in risk of hypertension. Moderate physical activity improved control of hypertension in Bouyei patients under treatment. Conclusively, hypertension awareness, treatment, and control were substantially lower in Bouyei than Han, particularly in the elderly population. Such ethnic disparities indicate that elderly Bouyei population should be targeted for tailored interventions in the future.

Phylogeographic Differentiation of Mitochondrial DNA in Han Chinese

PubMed Central

Yao, Yong-Gang; Kong, Qing-Peng; Bandelt, Hans-Jürgen; Kivisild, Toomas; Zhang, Ya-Ping

2002-01-01

To characterize the mitochondrial DNA (mtDNA) variation in Han Chinese from several provinces of China, we have sequenced the two hypervariable segments of the control region and the segment spanning nucleotide positions 10171–10659 of the coding region, and we have identified a number of specific coding-region mutations by direct sequencing or restriction-fragment–length–polymorphism tests. This allows us to define new haplogroups (clades of the mtDNA phylogeny) and to dissect the Han mtDNA pool on a phylogenetic basis, which is a prerequisite for any fine-grained phylogeographic analysis, the interpretation of ancient mtDNA, or future complete mtDNA sequencing efforts. Some of the haplogroups under study differ considerably in frequencies across different provinces. The southernmost provinces show more pronounced contrasts in their regional Han mtDNA pools than the central and northern provinces. These and other features of the geographical distribution of the mtDNA haplogroups observed in the Han Chinese make an initial Paleolithic colonization from south to north plausible but would suggest subsequent migration events in China that mainly proceeded from north to south and east to west. Lumping together all regional Han mtDNA pools into one fictive general mtDNA pool or choosing one or two regional Han populations to represent all Han Chinese is inappropriate for prehistoric considerations as well as for forensic purposes or medical disease studies. PMID:11836649

Racial differences of endothelial function and plasma endothelin 1 level in preclinical Tibetan and Han male population.

PubMed

Yang, B; Zhao, H; Zhang, J; Jiang, B; Li, C W; Cao, Y K; Cao, F

2016-07-01

The differences in endothelial function between Tibetan and Han nationality population have not been fully investigated. The aim of this work is to investigate the differences in endothelial function and plasma endothelin 1 (ET-1) concentration between Tibetan and Han male population. Totally 272 Tibetan male subjects aged 42.9 ± 9.4 years were enrolled in this study to stand for Tibetan population. All of them were native residents in Lhasa City. And 580 Qinghai-Tibet Railway constructors with Han nationality aged 41.8 ± 11.1 years were enrolled in this study to stand for Han nationality population. All of them were male subjects and lived in Lhasa City for at least 1 year. All subjects lived in the same high-altitude area (the altitude of Lhasa is 3658 m). Height, weight, waist circumference, hip circumference, systolic blood pressure, diastolic blood pressure were evaluated. Body mass index (BMI) was calculated. Brachial artery flow-mediated dilation (FMD) was measured in the fasting state using high-resolution B-mode ultrasound. Computer-assisted analysis software was used to calculate brachial artery diameters. Venous blood was sampled for the measurement of total cholesterol (CH), triglyceride (TG), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL) and HbA1c. Plasma ET-1 was quantitated using a commercially available ELISA kits. Totally 272 Tibetan subjects and 580 Han nationality subjects were enrolled in this study. BMI and waist-hip ratio in Tibetan subjects were much higher than those in Han subjects (p < 0.01). LDL cholesterol level and plasma ET-1 concentration in Tibetan subjects were significantly higher than Han subjects (p < 0.01). The baseline brachial artery diameter in Tibetan group was much higher than that of Han group (p < 0.01). The absolute and percent changes in brachial artery diameter were lower in Tibetan population compared with Han population (p < 0.01). The linear regression analysis showed that LDL cholesterol, and plasma ET-1 were correlated with FMD (p < 0.01). Endothelial function and plasma ET-1 concentration were different between Tibetan and Han male populations.

Effect of addition of nano-hydroxyapatite on physico-chemical and antibiofilm properties of calcium silicate cements.

PubMed

Guerreiro-Tanomaru, Juliane Maria; Vázquez-García, Fernando Antonio; Bosso-Martelo, Roberta; Bernardi, Maria Inês Basso; Faria, Gisele; Tanomaru, Mario

2016-01-01

Mineral Trioxide Aggregate (MTA) is a calcium silicate cement composed of Portland cement (PC) and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2) and hydroxyapatite nanoparticles (HAn). White MTA (Angelus, Brazil); PC (70%)+ZrO2 (30%); PC (60%)+ZrO2 (30%)+HAn (10%); PC (50%)+ZrO2 (30%)+HAn (20%) were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1) in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p>0.05) and these cements presented higher pH levels than MTA (p<0.05). The highest solubility was observed in PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p<0.05). MTA had the shortest initial setting time (p<0.05). All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05). Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05) after the post-manipulation period of 2 days. The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%), the final setting time and the E. faecalis antibiofilm activity of the cement.

Association between HLA-A and -B polymorphisms and susceptibility to Henoch-Schönlein purpura in Han and Mongolian children from Inner Mongolia.

PubMed

Ren, S M; Yang, G L; Liu, C Z; Zhang, C X; Shou, Q H; Yu, S F; Li, W C; Su, X L

2012-02-03

We examined a possible association between HLA-A and -B polymorphisms and susceptibility to Henoch-Schönlein purpura (HSP) in Han and Mongolian children in Inner Mongolia, through a case-control study. Two hundred and sixty-eight unrelated children were enrolled, including 56 Mongolian and 50 Han children with HSP, 66 healthy Mongolian and 96 healthy Han children as a control group. HLA-A and -B alleles were indentified by PCR-sequence-specific oligonucleotide analysis and were further analyzed by PCR-sequencing-based typing (SBT). Frequencies of HLA-A*11, HLA-B*15 in Mongolian patients and HLA-A*26, HLA-B*35, HLA-B*52 in Han patients were higher than those in the corresponding control group (P < 0.05), while frequencies of HLA-B*07 and -B*40 in Mongolian HSP patients were lower than those in the control group (P < 0.05). Further analysis using PCR-SBT showed that all HLA-A*11 were HLA-A*1101, and most HLA-B*15 were HLA-B*1501 in Mongolian HSP patients. All HLA-A*26 were HLA-A*2601 and HLA-B*35 were mostly HLA-B*3503 in Han patients. There were more Han patients with severe manifestations than Mongolian patients (P < 0.05). Frequencies of HLA-A*26, HLA-B*35 and HLA-B*52 in Han patients were higher than in Mongolian patients (P < 0.05). We conclude that HLA-A*11(*1101) and -B*15(*1501) are associated with susceptibility to HSP in Mongolian children and HLA-A*26(*2601), HLA-B*35(*3503) and HLA-B*52 are associated with susceptibility to HSP in Han children. HLA-B*07 and -B*40 may be protective genes in Mongolian children. The different frequencies of HLA-A and -B in Mongolian and Han children may be responsible for the different manifestations in these two ethnic groups.

Inner and inter population structure construction of Chinese Jiangsu Han population based on Y23 STR system

PubMed Central

Yang, Chun; Zhang, Jianqiu

2017-01-01

In this study, we analyzed the genetic polymorphisms of 23 Y-STR loci from PowerPlex® Y23 system in 916 unrelated healthy male individuals from Chinese Jiangsu Han, and observed 912 different haplotypes including 908 unique haplotypes and 4 duplicate haplotypes. The haplotype diversity reached 0.99999 and the discrimination capacity and match probability were 0.9956 and 0.0011, respectively. The gene diversity values ranged from 0.3942 at DYS438 to 0.9607 at DYS385a/b. Population differentiation within 10 Jiangsu Han subpopulations were evaluated by RST values and visualized in Neighbor-Joining trees and Multi-Dimensional Scaling plots as well as population relationships between the Jiangsu Han population and other 18 Eastern Asian populations. Such results indicated that the 23 Y-STR loci were highly polymorphic in Jiangsu Han population and played crucial roles in forensic application as well as population genetics. For the first time, we reported the genetic diversity of male lineages in Jiangsu Han population at a high-resolution level of 23 Y-STR set and consequently contributed to familial searching, offender tracking, and anthropology analysis of Jiangsu Han population. PMID:28704439

Pharmacokinetics of Lidocaine Hydrochloride Metabolized by CYP3A4 in Chinese Han Volunteers Living at Low Altitude and in Native Han and Tibetan Chinese Volunteers Living at High Altitude.

PubMed

Zhang, Juanling; Zhu, Junbo; Yao, Xingchen; Duan, Yabin; Zhou, Xuejiao; Yang, Meng; Li, Xiangyang

2016-01-01

To investigate the pharmacokinetics of lidocaine hydrochloride metabolized by cytochrome P450 3A4 (CYP3A4) in Chinese Han volunteers living at low altitude (LA) and in native Han and Tibetan Chinese volunteers living at high altitude, lidocaine hydrochloride 10 mg was given by intramuscular injection to 3 groups: Han volunteers living at LA, and native Han and Tibetan volunteers living at a high altitude. Blood samples were collected before the (baseline) study drug was given and at 0.25, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0 h after study drug administration. Lidocaine hydrochloride in plasma was determined by RP-HPLC. Pharmacokinetics parameters of lidocaine hydrochloride showed that there were no significant difference between the native Han and Tibetan volunteers, but the t(1/2) was 29.8 and 29.8% higher in 2 groups, respectively, than in the LA group. To study related mechanism, the effects of exposure to chronic high-altitude hypoxia (CHH) on the activity and expression of CYP3A1 were examined in rats. Rats were divided into LA, chronic moderate altitude hypoxia, and CHH groups. CHH caused significant decreases in the activity and protein and mRNA expression of rat CYP3A1 in vivo. This study found significant changes in the disposition of lidocaine hydrochloride in native healthy Tibetan and Han Chinese subjects living at a high altitude in comparison to healthy Han Chinese subjects living at LA, it might be due to significant decreases in the activity and protein and mRNA expression of CYP3A4 under CHH condition. © 2016 S. Karger AG, Basel.

[Physician satire and patient scorn in Hans Sachs' old Nürnberg and the physicians].

PubMed

Sauerbeck, K O

1993-01-01

Among the best poems of Hans Sachs quite a few describe patient-physician relationships in 16th century Nuremberg. These poems offer a vivid impression of the technical aspects as well as of the social context of medical treatment at the time. Hans Sachs ridiculed the doctors and their patients, implying that everybody attempted to cheat the other side, and he provides evidence of a great influence of charlatans on the country population. The poems of Hans Sachs are extraordinary pieces or art; their aesthetics, though, appear unusual to us today. Medical satire is part of all European cultures, and has been written throughout medical history. Most motives of later satires focussing on physicians may be traced to Hans Sachs' poetry.

Chemical study of the Chinese medicine Pi Han Yao

PubMed Central

PENG, TENG; ZHAO, FURONG; CHEN, XIAOYU; JIANG, GUIHUA; WANG, SHAONAN

2016-01-01

The aim of the present study was to ivnestigate the chemical constituents of the Chinese medicine Pi Han Yao (Gueldenstaedtia delavayi Franch) decoction. Following this, the quantitative determination of the formononetin and maackiain content in Pi Han Yao was established. The chemical constituents were isolated by column chromatography and their structures were elucidated by analysis of spectrometric data and chemical evidence. High-performance liquid chromatography (HPLC) was used for the determination of the formononetin and maackiain content in Pi Han Yao. Seven flavanones were isolated from the Pi Han Yao decoction. Five of the chemical structures were elucidated as 1, 7,2′-dihydroxy-4′-methoxy-isoflavanol; 2, maackiain; 3, formononetin-7-O-β-D-glucoside; 4, formononetin; and 5, 9-(β-D-ribofuranosyl)-adenosine. The other two compounds and their structures require further study. Additionally, the linear range of formononetin and maackiain were 0.03992–0.3992 and 0.0292–0.292 µg, and their recoveries were 100.31 and 100.44%. To the best of our knowledge, compounds 1–5 were obtained from Pi Han Yao for the first time. The HPLC method use for determination of formononetin and maackiain in Pi Han Yao was simple, accurate and reliable. Findings from the present study suggest that these methods may be used to evaluate the quality of Pi Han Yao and provide an experience basis for quality standards of this medicinal material. PMID:26893842

Synthesis of 6-Substituted-2,4-Diamino-5,6,7,8-Tetrahydropyrimido(4-5-d)Pyrimidines.

DTIC Science & Technology

1979-10-01

triaminopyrihidifle with substituted Andines 2, 1. Anilines 2 2. 0-Arylhydroxylami nes 3 3. Benzylamines 4 4. O-Benzyl hydroxylamines 4 5. PhenylethylamineS 5 6...by hydrazinolysis of the phthaliinide intermediate. 5. Phenylethylamines The reaction of 2,4,6-triaminopyrimidine with phenylethyl- amines and...5,6,7,8-tetrahydropyrimido L!,5-d_1 pyrimidines were excellent. These products were summarized in Table 1. The phenylethylamines were usually prepared

Iridium-catalyzed direct tetraborylation of perylene bisimides.

PubMed

Teraoka, Takuro; Hiroto, Satoru; Shinokubo, Hiroshi

2011-05-20

Treatment of perylene bisimides (PBIs) with bis(pinacolato)diboron in the presence of an iridium catalyst provides tetraborylated PBIs at 2,5,8,11-positions in good yields with perfect regioselectivity. The planar structure of the perylene core has been confirmed by X-ray diffraction analysis. Oxidation of tetraborylated PBI with hydroxylamine hydrochloride affords tetrahydroxy PBI in excellent yield, which exhibits a substantially blue-shifted absorption spectrum due to an intramolecular hydrogenbonding interaction between carbonyl and hydroxy groups.

Multiple copies of genes coding for electron transport proteins in the bacterium Nitrosomonas europaea.

PubMed

McTavish, H; LaQuier, F; Arciero, D; Logan, M; Mundfrom, G; Fuchs, J A; Hooper, A B

1993-04-01

The genome of Nitrosomonas europaea contains at least three copies each of the genes coding for hydroxylamine oxidoreductase (HAO) and cytochrome c554. A copy of an HAO gene is always located within 2.7 kb of a copy of a cytochrome c554 gene. Cytochrome P-460, a protein that shares very unusual spectral features with HAO, was found to be encoded by a gene separate from the HAO genes.

Formation and rearrangement of homoserine depsipeptides and depsiproteins in the α-ketoacid-hydroxylamine ligation with 5-oxaproline.

PubMed

Wucherpfennig, Thomas G; Rohrbacher, Florian; Pattabiraman, Vijaya R; Bode, Jeffrey W

2014-11-03

The primary products of the chemical ligation of α-ketoacids and 5-oxaproline peptides are esters, rather than the previously reported amides. The depsipeptide product rapidly rearranges to the amide in basic buffers. The formation of esters sheds light on possible mechanisms for the type II KAHA ligations and opens an avenue for the chemical synthesis of depsiproteins. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Etching characteristics of Si{110} in 20 wt% KOH with addition of hydroxylamine for the fabrication of bulk micromachined MEMS

NASA Astrophysics Data System (ADS)

Rao, A. V. Narasimha; Swarnalatha, V.; Pal, P.

2017-12-01

Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

Reactivity of cytosine and thymine in single-base-pair mismatches with hydroxylamine and osmium tetroxide and its application to the study of mutations.

PubMed Central

Cotton, R G; Rodrigues, N R; Campbell, R D

1988-01-01

The chemical reactivity of thymine (T), when mismatched with the bases cytosine, guanine, and thymine, and of cytosine (C), when mismatched with thymine, adenine, and cytosine, has been examined. Heteroduplex DNAs containing such mismatched base pairs were first incubated with osmium tetroxide (for T and C mismatches) or hydroxylamine (for C mismatches) and then incubated with piperidine to cleave the DNA at the modified mismatched base. This cleavage was studied with an internally labeled strand containing the mismatched T or C, such that DNA cleavage and thus reactivity could be detected by gel electrophoresis. Cleavage at a total of 13 T and 21 C mismatches isolated (by at least three properly paired bases on both sides) single-base-pair mismatches was identified. All T or C mismatches studied were cleaved. By using end-labeled DNA probes containing T or C single-base-pair mismatches and conditions for limited cleavage, we were able to show that cleavage was at the base predicted by sequence analysis and that mismatches in a length of DNA could be readily detected by such an approach. This procedure may enable detection of all single-base-pair mismatches by use of sense and antisense probes and thus may be used to identify the mutated base and its position in a heteroduplex. Images PMID:3260032

Activation of persulfate/copper by hydroxylamine via accelerating the cupric/cuprous redox couple.

PubMed

Zhou, Peng; Zhang, Jing; Liang, Juan; Zhang, Yongli; Liu, Ya; Liu, Bei

2016-01-01

Cuprous copper [Cu(I)] reacts with sodium persulfate (PDS) to generate sulfate radical SO4(-)•, but it has been seldom investigated owing to its instability and difficulty in dissolving it. This study proposes a new method to regenerate Cu(I) from cupric copper [Cu(II)] by addition of hydroxylamine (HA) to induce the continuous production of radicals through active PDS, and investigates the resulting enhanced methyl orange (MO) degradation efficiency and mechanism in the new system. HA accelerated the degradation of MO markedly in the pH range from 6.0 to 8.0 in the HA/Cu(II)/PDS process. Both SO4(-)• and hydroxyl radicals (•OH) were considered as the primary reactive radicals in the process. The MO degradation in the HA/Cu(II)/PDS process can be divided into three stages: the fast stage, the transitory stage, and the low stage. MO degradation was enhanced with increased dosage of PDS. Although high dosage of HA could accelerate the transformation of the Cu(II)/Cu(I) cycle to produce more reactive radicals, excess HA can quench the reactive radicals. This study indicates that through a copper-redox cycling mechanism by HA, the production of SO4(-)• and •OH can be strongly enhanced, and the effective pH range can be expanded to neutral conditions.

Enhanced Inactivation of Escherichia coli and MS2 Coliphage by Cupric Ion in the Presence of Hydroxylamine: Dual Microbicidal Effects.

PubMed

Kim, Hyung-Eun; Nguyen, Thuy T M; Lee, Hongshin; Lee, Changha

2015-12-15

The inactivation of Escherichia coli and MS2 coliphage by Cu(II) is found to be significantly enhanced in the presence of hydroxylamine (HA). The addition of a small amount of HA (i.e., 5-20 μM) increased the inactivation efficacies of E. coli and MS2 coliphage by 5- to 100-fold, depending on the conditions. Dual effects were anticipated to enhance the biocidal activity of Cu(II) by the addition of HA, viz. (i) the accelerated reduction of Cu(II) into Cu(I) (a stronger biocide) and (ii) the production of reactive oxidants from the reaction of Cu(I) with dissolved oxygen (evidenced by the oxidative transformation of methanol into formaldehyde). Deaeration enhanced the inactivation of E. coli but slightly decreased the inactivation efficacy of MS2 coliphage. The addition of 10 μM hydrogen peroxide (H2O2) greatly enhanced the MS2 inactivation, whereas the same concentration of H2O2 did not significantly affect the inactivation efficacy of E. coli Observations collectively indicate that different biocidal actions lead to the inactivation of E. coli and MS2 coliphage. The toxicity of Cu(I) is dominantly responsible for the E. coli inactivation. However, for the MS2 coliphage inactivation, the oxidative damage induced by reactive oxidants is as important as the effect of Cu(I).

Partially oxidized iridium clusters within dendrimers: size-controlled synthesis and selective hydrogenation of 2-nitrobenzaldehyde

NASA Astrophysics Data System (ADS)

Higaki, Tatsuya; Kitazawa, Hirokazu; Yamazoe, Seiji; Tsukuda, Tatsuya

2016-06-01

Iridium clusters nominally composed of 15, 30 or 60 atoms were size-selectively synthesized within OH-terminated poly(amidoamine) dendrimers of generation 6. Spectroscopic characterization revealed that the Ir clusters were partially oxidized. All the Ir clusters efficiently converted 2-nitrobenzaldehyde to anthranil and 2-aminobenzaldehyde under atmospheric hydrogen at room temperature in toluene via selective hydrogenation of the NO2 group. The selectivity toward 2-aminobenzaldehyde over anthranil was improved with the reduction of the cluster size. The improved selectivity is ascribed to more efficient reduction than intramolecular heterocyclization of a hydroxylamine intermediate on smaller clusters that have a higher Ir(0)-phase population on the surface.Iridium clusters nominally composed of 15, 30 or 60 atoms were size-selectively synthesized within OH-terminated poly(amidoamine) dendrimers of generation 6. Spectroscopic characterization revealed that the Ir clusters were partially oxidized. All the Ir clusters efficiently converted 2-nitrobenzaldehyde to anthranil and 2-aminobenzaldehyde under atmospheric hydrogen at room temperature in toluene via selective hydrogenation of the NO2 group. The selectivity toward 2-aminobenzaldehyde over anthranil was improved with the reduction of the cluster size. The improved selectivity is ascribed to more efficient reduction than intramolecular heterocyclization of a hydroxylamine intermediate on smaller clusters that have a higher Ir(0)-phase population on the surface. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01460g

Clinical physiology and mechanism of dizocilpine (MK-801)

PubMed Central

Somanathan, Ratnasamy

2010-01-01

Dizocilpine (MK-801), an extensively investigated drug possessing secondary amine and benzenoid functions, displays a wide array of biological properties, including anticonvulsant and anesthetic. There is scant discussion of biomechanism. A relevant, important finding is formation of oxidative metabolites in the hydroxylamine and phenolic categories. Analogy to cocaine metabolites suggests participation of redox entities, such as, hydroxylamine, nitroxide and nitrosonium, which can lead to electron transfer and radical formation. There is also similarity to metabolism by 3,3′-iminodipropionitrile and phencyclidine. Alternatively, the phenolic metabolites are well-known precursors of ET quinones. The review documents various physiological effects, mainly involving the central nervous system. Also of interest are the pro- and anti-oxidant properties. Considerable attention has been paid to MK-801 as an antagonist of the N-methyl-D-aspartate receptor in the glutamate category. This aspect is often associated with effects on the central nervous system. The review also provides recent literature dealing with MK-801/NMDA receptor in various areas of bioactivity. Studies were made of MK-801 involvement in working memory processing. Deficits in behavior were noted after administration of the drug. Treatment of mice with dizocilpine induced learning impairment. The influence of MK-801 on fear has been investigated. The substance is known to exert an analgesic effect in pain control. A number of reports deal with anesthetic properties. PMID:20716924

Synthesis, spectroscopic analysis and theoretical study of new pyrrole-isoxazoline derivatives

NASA Astrophysics Data System (ADS)

Rawat, Poonam; Singh, R. N.; Baboo, Vikas; Niranjan, Priydarshni; Rani, Himanshu; Saxena, Rajat; Ahmad, Sartaj

2017-02-01

In the present work, we have efficiently synthesized the pyrrole-isoxazoline derivatives (4a-d) by cyclization of substituted 4-chalconylpyrrole (3a-d) with hydroxylamine hydrochloride. The reactivity of substituted 4-chalconylpyrrole (3a-d), towards nucleophiles hydroxylamine hydrochloride was evaluated on the basis of electrophilic reactivity descriptors (fk+, sk+, ωk+) and they were found to be high at unsaturated β carbon of chalconylpyrrole indicating its more proneness to nucleophilic attack and thereby favoring the formation of reported new pyrrole-isoxazoline compounds (4a-d). The structures of newly synthesized pyrrole-isoxazoline derivatives were derived from IR, 1H NMR, Mass, UV-Vis and elemental analysis. All experimental spectral data corroborate well with the calculated spectral data. The FT-IR analysis shows red shifts in vN-H and vC = O stretching due to dimer formation through intermolecular hydrogen bonding. On basis set superposition error correction, the intermolecular interaction energy for (4a-d) is found to be 10.10, 9.99, 10.18, 11.01 and 11.19 kcal/mol respectively. The calculated first hyperpolarizability (β0) values of (4a-d) molecules are in the range of 7.40-9.05 × 10-30 esu indicating their suitability for non-linear optical (NLO) applications. Experimental spectral results, theoretical data, analysis of chalcone intermediates and pyrrole-isoxazolines find usefulness in advancement of pyrrole-azole chemistry.

Clinical physiology and mechanism of dizocilpine (MK-801): electron transfer, radicals, redox metabolites and bioactivity.

PubMed

Kovacic, Peter; Somanathan, Ratnasamy

2010-01-01

Dizocilpine (MK-801), an extensively investigated drug possessing secondary amine and benzenoid functions, displays a wide array of biological properties, including anticonvulsant and anesthetic. There is scant discussion of biomechanism. A relevant, important finding is formation of oxidative metabolites in the hydroxylamine and phenolic categories. Analogy to cocaine metabolites suggests participation of redox entities, such as, hydroxylamine, nitroxide and nitrosonium, which can lead to electron transfer and radical formation. There is also similarity to metabolism by 3,3'-iminodipropionitrile and phencyclidine. Alternatively, the phenolic metabolites are well-known precursors of ET quinones. The review documents various physiological effects, mainly involving the central nervous system. Also of interest are the pro- and ant-oxidant properties. Considerable attention has been paid to MK-801 as an antagonist of the N-methyl-D-aspartate receptor in the glutamate category. This aspect is often associated with effects on the central nervous system. The review also provides recent literature dealing with MK-801/NMDA receptor in various areas of bioactivity. Studies were made of MK-801 involvement in working memory processing. Deficits in behavior were noted after administration of the drug. Treatment of mice with dizocilpine induced learning impairment. The influence of MK-801 on fear has been investigated. The substance is known to exert an analgesic effect in pain control. A number of reports deal with anesthetic properties.

Green Mono Propulsion Activities at MSFC

NASA Technical Reports Server (NTRS)

Robinson, Joel W.

2014-01-01

In 2012, the National Aeronautics & Space Administration (NASA) Space Technology Mission Directorate (STMD) began the process of building an integrated technology roadmap, including both technology pull and technology push strategies. Technology Area 1 (TA-01) for Launch Propulsion Systems and TA-02 In-Space Propulsion are two of the fourteen TAs that provide recommendations for the overall technology investment strategy and prioritization of NASA's space technology activities. Identified within these documents are future needs of green propellant use. Green ionic liquid monopropellants and propulsion systems are beginning to be demonstrated in space flight environments. Starting in 2010 with the flight of Prisma, a 1-N thruster system began on-orbit demonstrations operating on ammonium dinitramide based propellant. The NASA Green Propellant Infusion Mission (GPIM) plans to demonstrate both 1-N, and 22-N hydroxyl ammonium nitrate (HAN)-based thrusters in a 2015 flight demonstration. In addition, engineers at MSFC have been evaluating green propellant alternatives for both thrusters and auxiliary power units (APUs). This paper summarizes the status of these development/demonstration activities and investigates the potential for evolution of green propellants from small spacecraft and satellites to larger spacecraft systems, human exploration, and launch system auxiliary propulsion applications.

Green Propulsion Auxiliary Power Unit Demonstration at MSFC

NASA Technical Reports Server (NTRS)

Robinson, Joel W.

2014-01-01

In 2012, the National Aeronautics & Space Administration (NASA) Space Technology Mission Directorate (STMD) began the process of building an integrated technology roadmap, including both technology pull and technology push strategies. Technology Area 1 (TA-01)1 for Launch Propulsion Systems is one of fourteen TAs that provide recommendations for the overall technology investment strategy and prioritization of NASA's space technology activities. Identified within TA-01 was the need for a green propulsion auxiliary power unit (APU) for hydraulic power by 2015. Engineers led by the author at the Marshall Space Flight Center (MSFC) have been evaluating green propellant alternatives and have begun the development of an APU test bed to demonstrate the feasibility of use. NASA has residual APU assets remaining from the retired Space Shuttle Program. Likewise, the F-16 Falcon fighter jet also uses an Emergency Power Unit (EPU) that has similar characteristics to the NASA hardware. Both EPU and APU components have been acquired for testing at MSFC. This paper will summarize the status of the testing efforts of green propellant from the Air Force Research Laboratory (AFRL) propellant AFM315E based on hydroxyl ammonium nitrate (HAN) with these test assets.

Systematic screening for CYP3A4 genetic polymorphisms in a Han Chinese population.

PubMed

Hu, Guo-Xin; Dai, Da-Peng; Wang, Hao; Huang, Xiang-Xin; Zhou, Xiao-Yang; Cai, Jie; Chen, Hao; Cai, Jian-Ping

2017-03-01

To systematically investigate the genetic polymorphisms of the CYP3A4 gene in a Han Chinese population. The promoter and exons of CYP3A4 gene in 1114 unrelated, healthy Han Chinese subjects were amplified and genotyped by direct sequencing. In total, five previously reported alleles (*1G, *4, *5, *18B and *23) were detected, of which one allele (*23) was reported for the first time in Han Chinese population. Additionally, seven novel exonic variants were also identified and designated as new alleles CYP3A4*28-*34. This study provides the most comprehensive data of CYP3A4 polymorphisms in Han Chinese population and detects the largest number of novel CYP3A4 alleles in one ethnic group.

The psychoanalytic process in the treatment of Little Hans.

PubMed

Bierman, Joseph S

2007-01-01

This paper studies the psychoanalytic process in the treatment of Little Hans, using Samuel Abrams's 1988 paper in which he defines the psychoanalytic process as the sequence of steps which appears within the mind of the patient as the treatment proceeds. As with the adult, the child can affectively recall or reenact the past in the transference, but the child also tries to promote whatever developmental phase is being clocked in. In January 1908 Max Graf, Hans's father and a member of the Vienna Psychoanalytic Society who was a musicologist, wrote Freud that his son had developed a fear that a horse would bite him in the street. Freud first suggested that the father give his son some enlightenment in the matter of sexual knowledge, such as his mother and other females have no "widdlers." The enlightenments only increased Hans's anxiety, prompting Freud to meet with Hans and his father and interpret the fear of the horse as fear of the father. While Max Graf was able to help Hans understand some dreams and fantasies, he exhibited a punitive attitude toward Hans's masturbation, which was reinforced by Freud's attitude that it was harmful. The father did not promote his son's development when he withheld knowledge of how babies are born, neither did Freud when he withheld any contrary suggestions from the father.

Development of HAN-based Liquid Propellant Thruster

NASA Astrophysics Data System (ADS)

Hisatsune, K.; Izumi, J.; Tsutaya, H.; Furukawa, K.

2004-10-01

Many of propellants that are applied to the conventional spacecraft propulsion system are toxic propellants. Because of its toxicity, considering the environmental pollution or safety on handling, it will be necessary to apply the "green" propellant to the spacecraft propulsion system. The purpose of this study is to apply HAN based liquid propellant (LP1846) to mono propellant thruster. Compared to the hydrazine that is used in conventional mono propellant thruster, HAN based propellant is not only lower toxic but also can obtain higher specific impulse. Moreover, HAN based propellant can be decomposed by the catalyst. It means there are the possibility of applying to the mono propellant thruster that can leads to the high reliability of the propulsion system.[1],[2] However, there are two technical subjects, to apply HAN based propellant to the mono propellant thruster. One is the high combustion temperature. The catalyst will be damaged under high temperature condition. The other is the low catalytic activity. It is the serious problem on application of HAN based propellant to the mono propellant thruster that is used for attitude control of spacecraft. To improve the catalytic activity of HAN based propellant, it is necessary to screen the best catalyst for HAN based propellant. The adsorption analysis is conducted by Monte Carlo Simulation to screen the catalyst metal for HAN and TEAN. The result of analysis shows the Iridium is the best catalyst metal for HAN and TEAN. Iridium is the catalyst metal that is used at conventional mono propellant thruster catalyst Shell405. Then, to confirm the result of analysis, the reaction test about catalyst is conducted. The result of this test is the same as the result of adsorption analysis. That means the adsorption analysis is effective in screening the catalyst metal. At the evaluating test, the various types of carrier of catalyst are also compared to Shell 405 to improve catalytic activity. The test result shows the inorganic porous media is superior to Shell405 in catalytic activity. Next, the catalyst life with HAN based propellant (LP1846) is evaluated. The Shell405 and inorganic porous media catalyst are compared at the life test. The test result shows the inorganic porous media catalyst is superior to Shell405 in catalyst life. In this paper, the detail of the result of adsorption analysis and evaluating test are reported.

Effect of addition of nano-hydroxyapatite on physico-chemical and antibiofilm properties of calcium silicate cements

PubMed Central

GUERREIRO-TANOMARU, Juliane Maria; VÁZQUEZ-GARCÍA, Fernando Antonio; BOSSO-MARTELO, Roberta; BERNARDI, Maria Inês Basso; FARIA, Gisele; TANOMARU, Mario

2016-01-01

ABSTRACT Objective Mineral Trioxide Aggregate (MTA) is a calcium silicate cement composed of Portland cement (PC) and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2) and hydroxyapatite nanoparticles (HAn). Material and Methods White MTA (Angelus, Brazil); PC (70%)+ZrO2 (30%); PC (60%)+ZrO2 (30%)+HAn (10%); PC (50%)+ZrO2 (30%)+HAn (20%) were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1) in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. Results There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p>0.05) and these cements presented higher pH levels than MTA (p<0.05). The highest solubility was observed in PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p<0.05). MTA had the shortest initial setting time (p<0.05). All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05). Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05) after the post-manipulation period of 2 days. Conclusions The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%), the final setting time and the E. faecalis antibiofilm activity of the cement. PMID:27383700

Prevalence, awareness, treatment, control and risk factors related to hypertension among urban adults in Inner Mongolia 2014: differences between Mongolian and Han populations.

PubMed

Li, Guoju; Wang, Hailing; Wang, Ke; Wang, Wenrui; Dong, Fen; Qian, Yonggang; Gong, Haiying; Xu, Guodong; Li, Yanlong; Pan, Li; Wang, Bin; Zhu, Guangjin; Shan, Guangliang

2016-04-01

Han and Mongolian populations constitute approximately 96% of the population of Inner Mongolia Autonomous Region, and the two ethnic groups have different genetic backgrounds and lifestyle. We aim to assess the prevalence, awareness, treatment, control, and related risk factors of hypertension among urban adults in Inner Mongolia, with the comparison of the differences between Mongolian and Han populations in this respect. Three thousand two hundred fifty-one individuals aged 20-80 years (2326 Han and 925 Mongolian) were selected using a multistage cluster sampling method from Inner Mongolia in 2014. The adjusted prevalence, awareness, treatment and control of hypertension were evaluated by the Logistic regression. In addition, possible interactions were also tested. When interactions were found significant, strata-specific analysis were performed. Multivariate logistic regression was used for estimating independent associations between risk factors and hypertension. The prevalence of hypertension was 27.47% for Han population, 31.46% for Mongolian population. The adjusted prevalence, awareness, treatment and control of hypertension were 26.45, 65.43, 78.24 and 48.28% in Han, and 31.30, 68.22, 85.57 and 50.55% in Mongolian, respectively. There was no significant difference in the adjusted awareness, treatment and control of hypertension among Mongolian and Han adult residents (all P >0.05). Lower prevalence of hypertension was associated with younger age and healthy weight in both Mongolian and Han adults. Within Han adults, high education, moderate physical activity and non-alcohol drinkers were additionally associated with lower prevalence of hypertension, whereas within Mongolian adults, lower prevalence was associated with being female. Among residents with medium education level, nondrinkers had 0.60 times lower odds of having hypertension than current drinkers (OR = 0.60, 95% CI: 0.44-0.82); among residents with high education level, nondrinkers has 0.65 times lower odds of having hypertension than current drinkers (OR = 0.65, 95% CI: 0.43-0.97). Mongolian population had a higher prevalence of hypertension than Han population. There were no significant difference between Mongolian and Han population in awareness, treatment and control of hypertension, which suggested that there was no difference between the two ethnicities in the distribution of health resources.

Research on the Solar Eclipse Records in the Wuxingzhi of Both {Han} Dynasties

NASA Astrophysics Data System (ADS)

Li, Y.

2015-09-01

In this paper, we investigate the paper Lianghan Rishi Kao (inspect the solar-eclipse records in Both {Han} dynasties) written by {Zhu Wenxin} when compared the solar-eclipse records with those in the book Zhongguo Gudai Tianxiang Jilu Zong ji (collection of Chinese ancient astronomical records), and find 38 (61) records with the same dates in Western (Eastern) {Han} dynasty, equal to 70% (85%) of total. Our results have 42 (61) with the same dates in Western (Eastern) {Han} dynasty as just 78% (85%) of the total. There are totally 126 solar-eclipse records in the Wuxingzhi of both {Han} Dynasties. We confirm that there are 21 no occurred, 7 invisible in the capital then, 9 occurred before sunrise, 1 after sunset, and the left 88 are seen, occupying 70% as usually occurred in the capital area. With the help of our transformation platform as from Chinese ancient 60-day-cycle style dates to Gregorian calendar dates, we check the date records of solar eclipses in the Wuxingzhi of both {Han} dynasties, and then review the accuracy of the calendar. The standard errors of month and day are respectively 0.31 month (0.17 month) and 0.97 day (0.74 day) in the Western (Eastern) {Han} dynasty. At the same time, the standard errors of solar location of the records are determined, they are 11.08° (6.63°) in Western (Eastern) {Han} dynasty, and after excluding the possible misrecords the accuracy changes to 9.30° (3.59°). If the Juxing (key star of this constellation) was the same in both {Han} dynasties, the average value of observation error of solar location in Eastern {Han} dynasty is 2.8°, far better than 8.2° in Western {Han} dynasty. Otherwise, they most likely appear in some constellations with larger deviation. We try to determine the Δ T (ET-UT) value of solar-eclipse records with the magnitude descriptions, and at the same time, it is concluded that the magnitude of Ji (total eclipse) is 0.969-1.0, Jijin (the sun is covered almost all) is 0.829-0.985, and Bujinrugou (the sun is not covered all and left like a hook) is 0.861-0.926, respectively.

[A prevalence study on mild cognitive impairment among the elderly populations of Mongolian and Han nationalities in a pastoral area of Inner Mongolia].

PubMed

Hu, Riletemuer; Zhao, Shi-gang; Wang, De-sheng; Wen, Shi-rong; Niu, Guang-ming; A, Rong; Wang, Zhi-guang; Jiang, Ming-fang; Zhang, Chun-yu

2012-04-01

To understand the epidemiological characteristics and distribution of mild cognitive impairment (MCI) in elderly populations from Mongolian and Han nationalities living in the pastoral areas of Inner Mongolia Autonomous Region of China. According to the MCI clinical diagnostic criteria from Diagnostic and Statistical Manual of Mental Disorders 4th revised edition (DSM-IV) by American Psychiatric Association, the individuals under study were at the age of 55 or over, with Mongolian or Han ethnicities and living in the pastoral area of Inner Mongolia. The crude MCI morbidity rates of Mongolian and Han of the study populations in the pastoral area of Inner Mongolia Autonomous Region of China was 19.48% (1782/9146) and the standardization morbidity was 18.98%. The crude MCI morbidity rates of both Mongolian and Han ethnicities were 17.46% (the standardization morbidity was 16.99%) and 20.60% (the standardization morbidity was 19.98%), respectively. There showed a significant positive correlation between the crude morbidities and age, also significantly increasing with the latter. In the Mongolian population, the morbidity increased from 12.17% at the age 55-59 to 27.78% at 85 while in the Han population, the morbidity increased from 15.50% at the age 55-59 to 23.53% at 85. In both the populations of Mongolian and Han, there was a statistically difference found between the morbidities of MCI (χ2=13.229, P=0.000). The morbidity was higher in Hans than in the Mongolians. However, there was no statistically significant difference noticed between the morbidities of MCI in the Mongolian males and females (χ2=2.376, P=0.123). There was statistically significant difference found between the morbidities of MCI in the Han males and females, with females having higher risk than males (χ2=24.470, P=0.000). The morbidity of MCI in the elderly Mongolian and Han populations from the pastoral area of Inner Mongolia Autonomous Region of China was considered to be quite high and correlated to age and gender.

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2010 CFR

2010-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Nitric oxide in plants: an assessment of the current state of knowledge

PubMed Central

Mur, Luis A. J.; Mandon, Julien; Persijn, Stefan; Cristescu, Simona M.; Moshkov, Igor E.; Novikova, Galina V.; Hall, Michael A.; Harren, Frans J. M.; Hebelstrup, Kim H.; Gupta, Kapuganti J.

2012-01-01

Background and aims After a series of seminal works during the last decade of the 20th century, nitric oxide (NO) is now firmly placed in the pantheon of plant signals. Nitric oxide acts in plant–microbe interactions, responses to abiotic stress, stomatal regulation and a range of developmental processes. By considering the recent advances in plant NO biology, this review will highlight certain key aspects that require further attention. Scope and conclusions The following questions will be considered. While cytosolic nitrate reductase is an important source of NO, the contributions of other mechanisms, including a poorly defined arginine oxidizing activity, need to be characterized at the molecular level. Other oxidative pathways utilizing polyamine and hydroxylamine also need further attention. Nitric oxide action is dependent on its concentration and spatial generation patterns. However, no single technology currently available is able to provide accurate in planta measurements of spatio-temporal patterns of NO production. It is also the case that pharmaceutical NO donors are used in studies, sometimes with little consideration of the kinetics of NO production. We here include in planta assessments of NO production from diethylamine nitric oxide, S-nitrosoglutathione and sodium nitroprusside following infiltration of tobacco leaves, which could aid workers in their experiments. Further, based on current data it is difficult to define a bespoke plant NO signalling pathway, but rather NO appears to act as a modifier of other signalling pathways. Thus, early reports that NO signalling involves cGMP—as in animal systems—require revisiting. Finally, as plants are exposed to NO from a number of external sources, investigations into the control of NO scavenging by such as non-symbiotic haemoglobins and other sinks for NO should feature more highly. By crystallizing these questions the authors encourage their resolution through the concerted efforts of the plant NO community. PMID:23372921

Enhancing uranium uptake by amidoxime adsorbent in seawater: An investigation for optimum alkaline conditioning parameters

DOE PAGES

Das, Sadananda; Tsouris, Costas; Zhang, Chenxi; ...

2015-09-07

A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 °C). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentration ofmore » ~7–8 ppm and pH 8. Fourier transform infrared spectroscopy and solid-state NMR analyses indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 °C resulted in an increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. The scanning electron microscopy showed that long conditioning times may also lead to adsorbent degradation.« less

Enhancing Uranium Uptake by Amidoxime Adsorbent in Seawater: An investigation for optimum alkaline conditioning parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Tsouris, Constantinos; Zhang, C.

2016-04-20

A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory (ORNL) by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 ºC). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentrationmore » of ~ 7-8 ppm and pH 8. FTIR and solid state NMR indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 ºC resulted in increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. Scanning electron microscopy showed that long conditioning times may also lead to adsorbent degradation« less

Palladium nanoparticles decorated on reduced graphene oxide rotating disk electrodes toward ultrasensitive hydrazine detection: effects of particle size and hydrodynamic diffusion.

PubMed

Krittayavathananon, Atiweena; Srimuk, Pattarachai; Luanwuthi, Santamon; Sawangphruk, Montree

2014-12-16

Although metal nanoparticle/graphene composites have been widely used as the electrode in electrochemical sensors, two effects, consisting of the particle size of the nanoparticles and the hydrodynamic diffusion of analytes to the electrodes, are not yet fully understood. In this work, palladium nanoparticles/reduced graphene oxide (PdNPs/rGO) composites were synthesized using an in situ polyol method. Palladium(II) ions and graphene oxide were reduced together with a reducing agent, ethylene glycol. By varying the concentration of palladium(II) nitrate, PdNPs with different sizes were decorated on the surface of rGO sheets. The as-fabricated PdNPs/rGO rotating disk electrodes (RDEs) were investigated toward hydrazine detection. Overall, a 3.7 ± 1.4 nm diameter PdNPs/rGO RDE exhibits high performance with a rather low limit of detection of about 7 nM at a rotation speed of 6000 rpm and provides a wide linear range of 0.1-1000 μM with R(2) = 0.995 at 2000 rpm. This electrode is highly selective to hydrazine without interference from uric acid, glucose, ammonia, caffeine, methylamine, ethylenediamine, hydroxylamine, n-butylamine, adenosine, cytosine, guanine, thymine, and l-arginine. The PdNPs/rGO RDEs with larger sizes show lower detection performance. Interestingly, the detection performance of the electrodes is sensitive to the hydrodynamic diffusion of hydrazine. The as-fabricated electrode can detect trace hydrazine in wastewater with high stability, demonstrating its practical use as an electrochemical sensor. These findings may lead to an awareness of the effect of the hydrodynamic diffusion of analyte that has been previously ignored, and the 3.7 ± 1.4 nm PdNPs/rGO RDE may be useful toward trace hydrazine detection, especially in wastewater from related chemical industries.

A Cry For Justice: The Voices of Chinese Workers

ERIC Educational Resources Information Center

Leung, Trini

2008-01-01

This report presents accounts based on first-hand interviews conducted by Han Dongfang, China's leading labor rights advocate, with workers across China. Han Dongfang was a leader of the Beijing Workers' Autonomous Federation (BWAF), an independent labor group organized during the Tiananmen Square protests. Han today carries on the fight from Hong…

Attachment and sibling rivalry in Little Hans: the fantasy of the two giraffes revisited.

PubMed

Wakefield, Jerome C

2007-01-01

Freud's interpretation of Little Hans's "phantasy of the two giraffes" is pivotal to his oedipal analysis that Hans has inchoate desires for sexual intercourse with his mother. Bowlby argued that Freud's focus on his oedipal theory led him to ignore preoedipal attachment-related factors that have equal plausibility in explaining the clinical data. However, Bowlby did not attempt to apply the attachment perspective to the interpretation of Hans's fantasies that form the core of the case material. A microanalysis of Hans's giraffe fantasy and the evidence used to support Freud's claims about it yields an attachment-based sibling rivalry account arguably of greater explanatory power than the oedipal account. Consistent with Bowlby's hypothesis, the evidence suggests that Hans's giraffe fantasy is about the sibling rivalry triangle involved in caregiver attachment access, rather than (or in addition to) the oedipal triangle. The issue of multiple levels of meaning and the methodological challenges raised by multiple determination is also considered. The giraffe fantasy's attachment-theoretic explanation encourages a rethinking of this classic case and strengthens Bowlby's claim that the case is fruitfully viewed from an attachment perspective.

Ancient DNA evidence supports the contribution of Di-Qiang people to the han Chinese gene pool.

PubMed

Zhao, Yong-Bin; Li, Hong-Jie; Li, Sheng-Nan; Yu, Chang-Chun; Gao, Shi-Zhu; Xu, Zhi; Jin, Li; Zhu, Hong; Zhou, Hui

2011-02-01

Han Chinese is the largest ethnic group in the world. During its development, it gradually integrated with many neighboring populations. To uncover the origin of the Han Chinese, ancient DNA analysis was performed on the remains of 46 humans (1700 to 1900 years ago) excavated from the Taojiazhai site in Qinghai province, northwest of China, where the Di-Qiang populations had previously lived. In this study, eight mtDNA haplogroups (A, B, D, F, M*, M10, N9a, and Z) and one Y-chromosome haplogroup (O3) were identified. All analyses show that the Taojiazhai population presents close genetic affinity to Tibeto-Burman populations (descendants of Di-Qiang populations) and Han Chinese, suggesting that the Di-Qiang populations may have contributed to the Han Chinese genetic pool. 2010 Wiley-Liss, Inc.

[Comparison of the differences in pain and the effect of ibuprofen in reducing endodontic flare-up after single-visit root canal therapy between Uyghur and Han patients with chronic apical periodontitis].

PubMed

Yan, Lei; Wang, Xin-Ying; Wan, Na; Wu, Pei-Ling

2017-04-01

To compare the incidence of postoperative pain of chronic periapical periodontitis patients with root canal therapy between Han and Uygur, and the effect of ibuprofen in reducing endodontic flare-up after single-visit root canal therapy between Uyghur and Han patients with chronic apical periodontitis, in order to provide a basis for clinical administration. Two hundred and fifty Uyghur and 250 Han patients with chronic apical periodontitis in their incisor, canine and premolar were collected, and randomly divided into 2 groups: experimental group and control group. After single-visit root canal therapy, Uyghur patients in the experimental group (UEG) and Han patients in the experimental group (HEG) took ibuprofen capsules according to the drug instructions; while Uyghur patients in the control group (UCG) and Han patients in the control group(HCG) took placebo capsules. Both doctors and patient kept blind from the drug capsules and group of the patients. The incidence, degree of endodontic Flare-up at 6, 12, 24, 48, 72 hours and 1 week after root canal therapy were recorded and analyzed by χ 2 test using SPSS11.0 software package. During the experiment, the incidence of E flare-up in Uygur patients was higher than in Han patients; the incidence of E flare-up in different groups in orders from high to low was: UCG>HCG>UEG>HEG. Chi-square test showed that there were significant differences between the two groups. In view of time distribution, most of flare-up happened between 24~48 hours after root canal therapy with the highest degree in all 4 groups. Regardless of the incidence or degree of flare-up, HEG and HCG were significantly greater than UEG and UCG. Ibuprofen can reduce and prevent flare-up for both Uyghur and Han patients, but it has better effect on Han patients.

Evaluation of the genetic parameters and mutation analysis of 22 STR loci in the central Chinese Han population.

PubMed

Hongdan, Wang; Bing, Kang; Ning, Su; Miao, He; Bo, Zhang; Yuxin, Guo; Bofeng, Zhu; Shixiu, Liao; Zhaoshu, Zeng

2017-01-01

At present, the Han nationality is China's main ethnic group and also the most populous nation in the world. This is a great resource to study microsatellite mutations and for the study of ethnogeny. The aim of this study is to investigate the genetic polymorphisms and mutations of 22 autosomal STR loci in 2475 individuals from Henan province, China. DNA is amplified and genotyped using PowerPlex™24 system. The gene frequencies, forensic parameters, and the mutation rate of the 22 STR loci are analyzed. A total of 295 alleles are observed in this Henan Han population, and the allelic frequencies ranged from 0.0003 to 0.5036. In order to investigate the genetic relationships between the Henan Han and the other 14 different populations, our present data were compared with previously published data for the same 15 STR loci. The results indicated that the Henan Han had closer genetic relationships the groups including Minnan Han, Maonan, Yi and Guangdong Han groups while the South morocco population, the Moroccan population, the Malay group, and the Uigur stand away from Henan Han. Except of D2S441, D13S317, PentaE, D2S1338, D5S818, TPOX and D19S433, the mutation events are found in the other 15 STR loci. A total of 40 mutation events are observed in the 15 STR loci. The mutation rates are ranged from 0 to 4.85 × 10 -3 . In this study, 39 mutations are single-step mutations, and only one at FGA comprised two steps. STR mutation is commonly existed in paternity testing, while there are no STR mutation studies of the 22 STR loci in the Henan Han population. It is of great importance in forensic individual discrimination and paternal testing.

Novel Pathways of Nitroaromatic Metabolism: Hydroxylamine Formation, Reactivity and Potential for Ring Fission for Destruction of TNT-CU1214

DTIC Science & Technology

2005-08-15

phase was terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported...terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported previously (2...Department of Defense HPLC High Performance Liquid Chromatography IPTG Isopropyl-β-D-1-thiogalactopyranoside LB Luria-Bertani Broth NB Nitrobenzene

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2011 CFR

2011-07-01

... 4.0 with pH 4.0 buffer and pH 7 with pH 7.0 buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3... hydrochloride solution, 100 grams per liter, pH adjusted to 4.00. 4.3Hydrochloric acid solution, 1.0 N and 0.1 N... magnetic stirrer. Confirm that the resin has dissolved. 5.4Adjust the resin/solvent solution to pH 4.0...

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2010 CFR

2010-07-01

... 4.0 with pH 4.0 buffer and pH 7 with pH 7.0 buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3... hydrochloride solution, 100 grams per liter, pH adjusted to 4.00. 4.3Hydrochloric acid solution, 1.0 N and 0.1 N... magnetic stirrer. Confirm that the resin has dissolved. 5.4Adjust the resin/solvent solution to pH 4.0...

Intragenic Mapping of Chemically Induced ad-7 Mutants of Schizosaccharomyces pombe

PubMed Central

Loprieno, Nicola

1967-01-01

Thirty adenine-requiring ad-7 mutants of Schizosaccharomyces pombe, induced by ethylmethanesulfonate, methyl-methanesulfonate, and hydroxylamine and exhibiting low spontaneous reversion frequencies, were located by intragenic recombination analysis. Their identification as ad-7 mutants was assessed in relation to two previously mapped ad-7 mutants. Each mutant was found to occupy a distinct mutational site; the smallest recombination fraction observed between the two closest mutational sites was of the order of 0.5 × 10−6. PMID:6051345

Hybrid microspheres

NASA Technical Reports Server (NTRS)

Yen, Richard C. K. (Inventor); Rembaum, Alan (Inventor)

1985-01-01

Substrates, particularly inert synthetic organic resin beads (10) or sheet (12) such as polystyrene are coated with a covalently bound layer (24) of polyacrolein by irradiation a solution (14) of acrolein or other aldehyde with high intensity radiation. Individual microspheres (22) are formed which attach to the surface to form the aldehyde containing layer (24). The aldehyde groups can be converted to other functional groups by reaction with materials such as hydroxylamine. Adducts of proteins such as antibodies or enzymes can be formed by direct reaction with the surface aldehyde groups.

Enhanced healing of rat calvarial critical size defect with selenium-doped lamellar biocomposites.

PubMed

Wang, Yanhua; Lv, Peng; Ma, Zhe; Zhang, Jingcheng

2013-10-01

A 3D porous lamellar selenium-containing nano-hydroxyapatite (SeHAN)/chitosan (CS) biocomposite was synthesized. The selenium-containing hydroxyapatite (HA) grains of 150~200 nm in length and 20~30 nm in width were observed by dynamic light scattering and transmission electron microscopy. A combination of X-ray diffraction, Fourier-transform infrared spectroscopy, and SEM indicated that HA particles were uniformly dispersed in chitosan matrix and there was a chemical interaction between chitosan and HA. Then, a standard critical size calvarial bone defect was created in Wistar rats. In group 1, no implant was made in the defect. In groups 2 and 3, HA nanoparticles (HAN)/CS biocomposite and SeHAN/CS biocomposite were implanted into the defect, respectively. After 4 weeks, the histological assessment clearly exhibited no significant changes, only found some living cells anchored in the periphery of the implants. After 8 and 12 weeks, most newly formed osteoid tissue was found in the SeHAN/CS implant group. Additionally, the newly formed osteoid tissue, both at the edge and in the center of implants, was bioactive and neovascularized. Microfocus computerized tomography measurements also confirmed the much better quality of the newly formed bone tissue in SeHAN/CS implant group than that in HAN/CS implant group (p < 0.01). Collectively, the SeHAN/CS biocomposite, as a bioactive bone grafting substitute, significantly enhanced the repair of bone defect.

Blood plasma response and urinary excretion of nitrite and nitrate in milk-fed calves after oral nitrite and nitrate administration.

PubMed

Hüsler, B R.; Blum, J W.

2001-05-01

There is marked endogenous production of nitrate in young calves. Here we have studied the contribution of exogenous nitrate and nitrite to plasma concentrations and urinary excretion of nitrite and nitrate in milk-fed calves. In experiment 1, calves were fed 0 or 200 &mgr;mol nitrate or nitrite/kg(0.75) or 100 &mgr;mol nitrite plus 100 &mgr;mol nitrate/kg(0.75) with milk for 3 d. In experiment 2, calves were fed 400 &mgr;mol nitrate or nitrite/kg(0.75) with milk for 1 d. Plasma nitrate rapidly and comparably increased after feeding nitrite, nitrate or nitrite plus nitrate. The rise of plasma nitrate was greater if 400 than 200 &mgr;mol nitrate or nitrite/kg(0.75) were fed. Plasma nitrate decreased slowly after the 3-d administration of 200 &mgr;mol nitrate or nitrite/kg(0.75) and reached pre-experimental concentrations 4 d later. Urinary nitrate excretions nearly identically increased if nitrate, nitrite or nitrite plus nitrate were administered and excreted amounts were greater if 400 than 200 &mgr;mol nitrate or nitrite/kg(0.75) were fed. After nitrite ingestion plasma nitrite only transiently increased after 2 and 4 h and urinary excretion rates remained unchanged. Plasma nitrate concentration remained unchanged if milk was not supplemented with nitrite or nitrate. Nitrate concentrations were stable for 24 h after addition of nitrite to full blood in vitro, whereas nitrite concentrations decreased within 2 h. In conclusion, plasma nitrate concentrations and urinary nitrate excretions are enhanced dose-dependently by feeding low amounts of nitrate and nitrite, whereas after ingested nitrite only a transient and small rise of plasma nitrite is observed because of rapid conversion to nitrate.

Nitrate Transport Is Independent of NADH and NAD(P)H Nitrate Reductases in Barley Seedlings 1

PubMed Central

Warner, Robert L.; Huffaker, Ray C.

1989-01-01

Barley (Hordeum vulgare L.) has NADH-specific and NAD(P)H-bispecific nitrate reductase isozymes. Four isogenic lines with different nitrate reductase isozyme combinations were used to determine the role of NADH and NAD(P)H nitrate reductases on nitrate transport and assimilation in barley seedlings. Both nitrate reductase isozymes were induced by nitrate and were required for maximum nitrate assimilation in barley seedlings. Genotypes lacking the NADH isozyme (Az12) or the NAD(P)H isozyme (Az70) assimilated 65 or 85%, respectively, as much nitrate as the wild type. Nitrate assimilation by genotype (Az12;Az70) which is deficient in both nitrate reductases, was only 13% of the wild type indicating that the NADH and NAD(P)H nitrate reductase isozymes are responsible for most of the nitrate reduction in barley seedlings. For all genotypes, nitrate assimilation rates in the dark were about 55% of the rates in light. Hypotheses that nitrate reductase has direct or indirect roles in nitrate uptake were not supported by this study. Induction of nitrate transporters and the kinetics of net nitrate uptake were the same for all four genotypes indicating that neither nitrate reductase isozyme has a direct role in nitrate uptake in barley seedlings. PMID:11537465

Nitrate transport is independent of NADH and NAD(P)H nitrate reductases in barley seedlings

NASA Technical Reports Server (NTRS)

Warner, R. L.; Huffaker, R. C.

1989-01-01

Barley (Hordeum vulgare L.) has NADH-specific and NAD(P)H-bispecific nitrate reductase isozymes. Four isogenic lines with different nitrate reductase isozyme combinations were used to determine the role of NADH and NAD(P)H nitrate reductases on nitrate transport and assimilation in barley seedlings. Both nitrate reductase isozymes were induced by nitrate and were required for maximum nitrate assimilation in barley seedlings. Genotypes lacking the NADH isozyme (Az12) or the NAD(P)H isozyme (Az70) assimilated 65 or 85%, respectively, as much nitrate as the wild type. Nitrate assimilation by genotype (Az12;Az70) which is deficient in both nitrate reductases, was only 13% of the wild type indicating that the NADH and NAD(P)H nitrate reductase isozymes are responsible for most of the nitrate reduction in barley seedlings. For all genotypes, nitrate assimilation rates in the dark were about 55% of the rates in light. Hypotheses that nitrate reductase has direct or indirect roles in nitrate uptake were not supported by this study. Induction of nitrate transporters and the kinetics of net nitrate uptake were the same for all four genotypes indicating that neither nitrate reductase isozyme has a direct role in nitrate uptake in barley seedlings.

Annual Conference (4th) on HAN-Based Liquid Propellants. Volume 2

DTIC Science & Technology

1989-05-01

TEFLON STOPCOCK pH METERI HAN PRODUCT RESERVOIR MAGNETIC STIRRER I 148 EQUIPMENT FOR ION EXCHANGE RESIN HNO 3 + HAN [~0.6 M HNO 3 1 __ REGENERANT [10% NH4...34Study of Thermal Diffusive-Reactive Instability in Liquid Propellants: The Effects of Surface Tension and Gravity " by R. C. Armstrong and S. B. Margolis

Development of accelerated net nitrate uptake. [Zea mays L

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKown, C.T.; McClure, P.R.

1988-05-01

Upon initial nitrate exposure, net nitrate uptake rates in roots of a wide variety of plants accelerate within 6 to 8 hours to substantially greater rates. Effects of solution nitrate concentrations and short pulses of nitrate ({le}1 hour) upon nitrate-induced acceleration of nitrate uptake in maize (Zea mays L.) were determined. Root cultures of dark-grown seedlings, grown without nitrate, were exposed to 250 micromolar nitrate for 0.25 to 1 hour or to various solution nitrate concentration (10-250 micromolar) for 1 hour before returning them to a nitrate-free solution. Net nitrate uptake rates were assayed at various periods following nitrate exposuremore » and compared to rates of roots grown either in the absence of nitrate (CaSO{sub 4}-grown) or with continuous nitrate for at least 20 hours. Three hours after initial nitrate exposure, nitrate pulse treatments increased nitrate uptake rates three- to four-fold compared to the rates of CaSO{sub 4}-grown roots. When cycloheximide (5 micrograms per milliliter) was included during a 1-hour pulse with 250 micromolar nitrate, development of the accelerated nitrate uptake state was delayed. Otherwise, nitrate uptake rates reached maximum values within 6 hours before declining. Maximum rates, however, were significantly less than those of roots exposed continuously for 20, 32, or 44 hours. Pulsing for only 0.25 hour with 250 micromolar nitrate and for 1 hour with 10 micromolar caused acceleration of nitrate uptake, but the rates attained were either less than or not sustained for a duration comparable to those of roots pulsed for 1 hour with 250 micromolar nitrate. These results indicate that substantial development of nitrate-induced accelerated nitrate uptake state can be achieved by small endogenous accumulations of nitrate, which appear to moderate the activity or level of root nitrate uptake.« less

The Hazard Notification System (HANS)

NASA Astrophysics Data System (ADS)

Snedigar, S. F.; Venezky, D. Y.

2009-12-01

The Volcano Hazards Program (VHP) has developed a Hazard Notification System (HANS) for distributing volcanic activity information collected by scientists to airlines, emergency services, and the general public. In the past year, data from HANS have been used by airlines to make decisions about diverting or canceling flights during the eruption of Mount Redoubt. HANS was developed to provide a single system that each of the five U.S. volcano observatories could use for communicating and storing volcanic information about the 160+ potentially active U.S. volcanoes. The data that cover ten tables and nearly 100 fields are now stored in similar formats, and the information can be released in styles requested by our agency partners, such as the International Civil Aviation Organization (ICAO). Currently, HANS has about 4500 reports stored; on average, two - three reports are added daily. HANS (at its most basic form) consists of a user interface for entering data into one of many release types (Daily Status Reports, Weekly Updates, Volcano Activity Notifications, etc.); a database holding previous releases as well as observatory information such as email address lists and volcano boilerplates; and a transmission system for formatting releases and sending them out by email or other web related system. The user interface to HANS is completely web based, providing access to our observatory scientists from any online PC. The underlying database stores the observatory information and drives the observatory and program websites' dynamic updates and archived information releases. HANS also runs scripts for generating several different feeds including the program home page Volcano Status Map. Each observatory has the capability of running an instance of HANS. There are currently three instances of HANS and each instance is synchronized to all other instances using a master-slave environment. Information can be entered on any node; slave nodes transmit data to the master node, and the master retransmits that data to all slave nodes. All data transfer between instances uses the Simple Object Access Protocol (SOAP) as the envelope in which data are transmitted between nodes. The HANS data synchronization not only works as a backup feature, but also acts as a simple fault-tolerant system. Information from any observatory can be entered on any instance, and still be transmitted to the specified observatory's distribution list, which provides added flexibility if there is a disruption in access from an area that needs to send an update. Additionally, having the same information available on our multiple websites is necessary for communicating our scientists' most up-to-date information.

Ancient DNA reveals genetic connections between early Di-Qiang and Han Chinese.

PubMed

Li, Jiawei; Zeng, Wen; Zhang, Ye; Ko, Albert Min-Shan; Li, Chunxiang; Zhu, Hong; Fu, Qiaomei; Zhou, Hui

2017-12-04

Ancient Di-Qiang people once resided in the Ganqing region of China, adjacent to the Central Plain area from where Han Chinese originated. While gene flow between the Di-Qiang and Han Chinese has been proposed, there is no evidence to support this view. Here we analyzed the human remains from an early Di-Qiang site (Mogou site dated ~4000 years old) and compared them to other ancient DNA across China, including an early Han-related site (Hengbei site dated ~3000 years old) to establish the underlying genetic relationship between the Di-Qiang and ancestors of Han Chinese. We found Mogou mtDNA haplogroups were highly diverse, comprising 14 haplogroups: A, B, C, D (D*, D4, D5), F, G, M7, M8, M10, M13, M25, N*, N9a, and Z. In contrast, Mogou males were all Y-DNA haplogroup O3a2/P201; specifically one male was further assigned to O3a2c1a/M117 using targeted unique regions on the non-recombining region of the Y-chromosome. We compared Mogou to 7 other ancient and 38 modern Chinese groups, in a total of 1793 individuals, and found that Mogou shared close genetic distances with Taojiazhai (a more recent Di-Qiang population), Hengbei, and Northern Han. We modeled their interactions using Approximate Bayesian Computation, and support was given to a potential admixture of ~13-18% between the Mogou and Northern Han around 3300-3800 years ago. Mogou harbors the earliest genetically identifiable Di-Qiang, ancestral to the Taojiazhai, and up to ~33% paternal and ~70% of its maternal haplogroups could be found in present-day Northern Han Chinese.

Distribution of Candida albicans in the oral cavity of children aged 3-5 years of Uygur and Han nationality and their genotype in caries-active groups.

PubMed

Wu, N; Lin, J; Wu, L; Zhao, J

2015-01-30

We analyzed the distribution of Candida albicans in the oral cavity of 3-5-year-old children of Uygur and Han nationalities as well as their genotypes in caries-active groups in the Urumqi municipality. CHROMagar Candida was separately cultivated, and we identified 359 Uygur and Han children aged 3-5 years. We randomly selected 20 Han children and 20 Uygur children for this study. We chose a bacterial strain for polymerase chain reaction (PCR) 25S rDNA genotyping and random amplified polymorphic DNA (RAPD) genotyping. The rate of caries-active in Han children was higher than that in Uygur children, with values of 39.6 and 24.3%, respectively. The detection rate of C. albicans was closely correlated to the caries filling index classification (X(2) = 31.037, P = 0.000, r = 0.421; X(2) = 80.454, P = 0.000, r = 0.497). PCR of 25S rDNA from 40 strains of Han and Uygur children revealed 3 genotypes, while RAPD analysis revealed 5 genotypes. The distribution of 25S rDNA genotyping of Han children from PCR differed from that of Uygur children (X(2) = 7.697, P = 0.021), both of which were mainly the A type. RAPD genotyping of both Han and Uygur children showed similar results (X(2) = 1.573, P = 0.814). There were differences in the distributions of C. albicans in children of different nationalities. C. albicans is a key factor causing caries. The PCR 25S rDNA genotyping method is simple and sensitive, while the RAPD genotyping method is reliable and comprehensive.

Prevalence of Diabetes and Associated Factors in the Uyghur and Han Population in Xinjiang, China.

PubMed

Gong, Haiying; Pa, Lize; Wang, Ke; Mu, Hebuli; Dong, Fen; Ya, Shengjiang; Xu, Guodong; Tao, Ning; Pan, Li; Wang, Bin; Shan, Guangliang

2015-10-14

To estimate the prevalence of diabetes and identify risk factors in the Uyghur and Han population in Xinjiang, China. A cross-sectional study in urban and rural areas in Xinjiang, including 2863 members of the Uyghur population and 3060 of the Han population aged 20 to 80 years, was conducted from June 2013 to August 2013. Data on fasting plasma glucose (FPG) and personal history of diabetes were used to estimate the prevalence of diabetes. Data on demographic characteristics, lifestyle risk factors, and lipid profiles were collected to identify risks factors using the multivariate logistic regression model. In urban areas, the age- and gender-standardized prevalence of diabetes was 8.21%, and the age- and gender-standardized prevalence of diabetes was higher in the Uyghur population (10.47%) than in the Han population (7.36%). In rural areas, the age- and gender-standardized prevalence of diabetes was 6.08%, and it did not differ significantly between the Uyghur population (5.71%) and the Han population (6.59%). The results of the multivariate logistic regression analysis showed that older age, obesity, high triglycerides (TG), and hypertension were all associated with an increased risk of diabetes in the Uyghur and Han population. Urban residence and low high-density lipoprotein cholesterol (HDL-C) were associated with an increased risk of diabetes in the Uyghur population. Being an ex-drinker was associated with an increased risk of diabetes and heavy physical activity was associated with a decreased risk of diabetes in the Han population. Our study indicates that diabetes is more prevalent in the Uyghur population compared with the Han population in urban areas. Strategies aimed at the prevention of diabetes require ethnic targeting.

Differences of prevalence of dyslipidemia and risk factors related to LDL-c in the patients with abnormal fasting glucose between Uygur and Han in Xinjiang.

PubMed

Quan, Li; Hu, Lin; Zhang, Li; Jiang, Sheng

2015-01-01

To evaluate the incidence of dyslipidemia among Uygur and Han patients with impaired fasting glucose (IFG). To investigate the influence factors on LDL-c in this population. This cross-sectional study included a total of 4709 participants, consisting of Uygurs patients (n=2053) and Han patients (n=2656) from Xinjiang province, who were screened for diabetes mellitus. A stratified multistage sampling design was used to collect the participants. The influence factors on LDL-c were analyzed by Logistic regression analysis. Among the IFG patients (n=1757), Uighur IFG group had a higher prevalence of dyslipidemia than that of Han IFG group, 99.8% vs. 63.7%, P<0.05. Similar trends were existed in the prevalence of hypercholesteremia, hypertriglyceridemia, high LDL-c and low HDL-c (all P<0.05). Among the Uighur groups, IFG group had higher dyslipidemia rate than that of euglycemia group (74%). However, there was no such difference in the Han groups. Logistic regression analysis revealed that risk factors associated with LDL-c were age, total cholesterol and 2 h postprandial blood glucose for the Uighur IFG patients. However, gender and total cholesterol were risk factors for Han IFG patients. Uighur IFG patients had higher incidence of dyslipidemia than that of Han IFG patients. For Uyghur IFG patients, closing follow-up of total cholesterol and 2 h postprandial blood glucose were necessary. As to the Han IFG patients, we should pay more attention to male and total cholesterol in order to lower LDL-c levels. So, appropriately preventive and therapeutic measures should be chosen based on the characteristics of abnormal lipid profiles in different nationality.

Three new species of the genus Xiphidiopsis Redtenbacher, 1891 (Orthoptera: Tettigoniidae: Meconematinae) in China.

PubMed

Han, Li; Di, Juan-Xia; Chang, Yan-Lin; Shi, Fu-Ming

2015-09-17

The article reported three new species of the genus Xiphidiopsis Redtenbacher, 1891 in China: Xiphidiopsis (Xiphidiopsis) minorincisus Han, Chang & Shi sp. nov., Xiphidiopsis (Xiphidiopsis) protensus Han, Chang & Shi sp. nov. and Xiphidiopsis (Xiphidiopsis) anisolobulus Han, Di & Shi sp. nov. The type material is deposited in the Museum of Hebei University, Baoding, P. R. China.

The Power of Knowledge: A Critical Analysis of the Depiction of Ethnic Minorities in China's Elementary Textbooks

ERIC Educational Resources Information Center

Chu, Yiting

2015-01-01

This study critically analyzes knowledge about: (1) ethnic minority groups; (2) the dominant Han group; and (3) the interaction between ethnic minorities and Han presented in three types of elementary textbooks used in China. The analysis reveals that the knowledge about and the values and beliefs of the Han people are overwhelmingly dominant in…

Short-term effects of a high nitrate diet on nitrate metabolism in healthy individuals.

PubMed

Bondonno, Catherine P; Liu, Alex H; Croft, Kevin D; Ward, Natalie C; Puddey, Ian B; Woodman, Richard J; Hodgson, Jonathan M

2015-03-12

Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake.

A panel of ancestry informative markers to estimate and correct potential effects of population stratification in Han Chinese.

PubMed

Qin, Pengfei; Li, Zhiqiang; Jin, Wenfei; Lu, Dongsheng; Lou, Haiyi; Shen, Jiawei; Jin, Li; Shi, Yongyong; Xu, Shuhua

2014-02-01

Population stratification acts as a confounding factor in genetic association studies and may lead to false-positive or false-negative results. Previous studies have analyzed the genetic substructures in Han Chinese population, the largest ethnic group in the world comprising ∼20% of the global human population. In this study, we examined 5540 Han Chinese individuals with about 1 million single-nucleotide polymorphisms (SNPs) and screened a panel of ancestry informative markers (AIMs) to facilitate the discerning and controlling of population structure in future association studies on Han Chinese. Based on genome-wide data, we first confirmed our previous observation of the north-south differentiation in Han Chinese population. Second, we developed a panel of 150 validated SNP AIMs to determine the northern or southern origin of each Han Chinese individual. We further evaluated the performance of our AIMs panel in association studies in simulation analysis. Our results showed that this AIMs panel had sufficient power to discern and control population stratification in Han Chinese, which could significantly reduce false-positive rates in both genome-wide association studies (GWAS) and candidate gene association studies (CGAS). We suggest this AIMs panel be genotyped and used to control and correct population stratification in the study design or data analysis of future association studies, especially in CGAS which is the most popular approach to validate previous reports on genetic associations of diseases in post-GWAS era.

Anticancer and antiviral effects and inactivation of S-adenosyl-L-homocysteine hydrolase with 5'-carboxaldehydes and oximes synthesized from adenosine and sugar-modified analogues.

PubMed

Wnuk, S F; Yuan, C S; Borchardt, R T; Balzarini, J; De Clercq, E; Robins, M J

1997-05-23

Selectively protected adenine nucleosides were converted into 5'-carboxaldehyde analogues by Moffatt oxidation (dimethyl sulfoxide/dicyclohexylcarbodiimide/dichloroacetic acid) or with the Dess-Martin periodinane reagent. Hydrolysis of a 5'-fluoro-5'-S-methyl-5'-thio (alpha-fluoro thioether) arabinosyl derivative also gave the 5'-carboxaldehyde. Treatment of 5'-carboxaldehydes with hydroxylamine [or O-(methyl, ethyl, and benzyl)hydroxylamine] hydrochloride gave E/Z oximes. Treatment of purified oximes with aqueous trifluoroacetic acid and acetone effected trans-oximation to provide clean samples of 5'-carboxaldehydes. Adenosine (Ado)-5'-carboxaldehyde and its 4'-epimer are potent inhibitors of S-adenosyl-L-homocysteine (AdoHcy) hydrolase. They bind efficiently to the enzyme and undergo oxidation at C3' to give 3'-keto analogues with concomitant reduction of the NAD+ cofactor to give an inactive, tightly bound NADH-enzyme complex (type I cofactor-depletion inhibition). Potent type I inhibition was observed with 5'-carboxaldehydes that contain a ribo cis-2',3'-glycol. Their oxime derivatives are "proinhibitors" that undergo enzyme-catalyzed hydrolysis to release the inhibitors at the active site. The 2'-deoxy and 2'-epimeric (arabinosyl) analogues were much weaker inhibitors, and the 3'-deoxy compounds bind very weakly. Ado-5'-carboxaldehyde oxime had potent cytotoxicity in tumor cell lines and was toxic to normal human cells. Analogues had weaker cytotoxic and antiviral potencies, and the 3'-deoxy compounds were essentially devoid of cytotoxic and antiviral activity.

Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants.

PubMed

Hou, Xiaojing; Huang, Xiaopeng; Jia, Falong; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

2017-05-02

In this study, we construct a surface Fenton system with hydroxylamine (NH 2 OH), goethite (α-FeOOH), and H 2 O 2 (α-FeOOH-HA/H 2 O 2 ) to degrade various organic pollutants including dyes (methyl orange, methylene blue, and rhodamine B), pesticides (pentachlorophenol, alachlor, and atrazine), and antibiotics (tetracycline, chloramphenicol, and lincomycin) at pH 5.0. In this surface Fenton system, the presence of NH 2 OH could greatly promote the H 2 O 2 decomposition on the α-FeOOH surface to produce ·OH without releasing any detectable iron ions during the alachlor degradation, which was different from some previously reported heterogeneous Fenton counterparts. Moreover, the ·OH generation rate constant of this surface Fenton system was 10 2 -10 4 times those of previous heterogeneous Fenton processes. The interaction between α-FeOOH and NH 2 OH was investigated with using attenuated total reflectance Fourier transform infrared spectroscopy and density functional theory calculations. The effective degradation of organic pollutants in this surface Fenton system was ascribed to the efficient Fe(III)/Fe(II) cycle on the α-FeOOH surface promoted by NH 2 OH, which was confirmed by X-ray photoelectron spectroscopy analysis. The degradation intermediates and mineralization of alachlor in this surface Fenton system were then systematically investigated using total organic carbon and ion chromatography, liquid chromatography-mass spectrometry, and gas chromatography-mass spectrometry. This study offers a new strategy to degrade organic pollutants and also sheds light on the environmental effects of goethite.

Pressure Dependence of the Liquid-Liquid Phase Transition of Nanopore Water Doped Slightly with Hydroxylamine, and a Phase Behavior Predicted for Pure Water

NASA Astrophysics Data System (ADS)

Nagoe, Atsushi; Iwaki, Shinji; Oguni, Masaharu; Tôzaki, Ken-ichi

2014-09-01

Phase transition behaviors of confined pure water and confined water doped with a small amount of hydroxylamine (HA) with a mole fraction of xHA = 0.03 were examined by high-pressure differential thermal analyses at 0.1, 50, 100, and 150 MPa; the average diameters of silica pores used were 2.0 and 2.5 nm. A liquid-liquid phase transition (LLPT) of the confined HA-doped water was clearly observed and its pressurization effect could be evaluated, unlike in the experiments on undoped water. It was found that pressurization causes the transition temperature (Ttrs) to linearly decrease, indicating that the low-temperature phase has a lower density than the high-temperature one. Transition enthalpy (ΔtrsH) decreased steeply with increasing pressure. Considering the linear decrease in Ttrs with increasing pressure, the steep decrease in ΔtrsH indicates that the LLPT effect of the HA-doped water attenuates with pressure. We present a new scenario of the phase behavior concerning the LLPT of pure water based on the analogy from the behavior of slightly HA-doped water, where a liquid-liquid critical point (LLCP) and a coexistence line are located in a negative-pressure regime but not in a positive-pressure one. It is reasonably understood that doping a small amount of HA into water results in negative chemical pressurization and causes the LLPT to occur even at ambient pressure.

Methyl-hydroxylamine as an efficacious antibacterial agent that targets the ribonucleotide reductase enzyme.

PubMed

Julián, Esther; Baelo, Aida; Gavaldà, Joan; Torrents, Eduard

2015-01-01

The emergence of multidrug-resistant bacteria has encouraged vigorous efforts to develop antimicrobial agents with new mechanisms of action. Ribonucleotide reductase (RNR) is a key enzyme in DNA replication that acts by converting ribonucleotides into the corresponding deoxyribonucleotides, which are the building blocks of DNA replication and repair. RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity. However, the high toxicity of these current drugs to eukaryotic cells does not permit their use as antibacterial agents. Here, we present a radical scavenger compound that inhibited bacterial RNR, and the compound's activity as an antibacterial agent together with its toxicity in eukaryotic cells were evaluated. First, the efficacy of N-methyl-hydroxylamine (M-HA) in inhibiting the growth of different Gram-positive and Gram-negative bacteria was demonstrated, and no effect on eukaryotic cells was observed. M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa. Thus, given the M-HA activity against these two bacteria, our results showed that M-HA has intracellular antimycobacterial activity against BCG-infected macrophages, and it is efficacious in partially disassembling and inhibiting the further formation of P. aeruginosa biofilms. Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm. Overall, our results suggest the vast potential of M-HA as an antibacterial agent, which acts by specifically targeting a bacterial RNR enzyme.

Combination of cupric ion with hydroxylamine and hydrogen peroxide for the control of bacterial biofilms on RO membranes.

PubMed

Lee, Hye-Jin; Kim, Hyung-Eun; Lee, Changha

2017-03-01

Combinations of Cu(II) with hydroxylamine (HA) and hydrogen peroxide (H 2 O 2 ) (i.e., Cu(II)/HA, Cu(II)/H 2 O 2 , and Cu(II)/HA/H 2 O 2 systems) were investigated for the control of P. aeruginosa biofilms on reverse osmosis (RO) membranes. These Cu(II)-based disinfection systems effectively inactivated P. aeruginosa cells, exhibiting different behaviors depending on the state of bacterial cells (planktonic or biofilm) and the condition of biofilm growth and treatment (normal or pressurized condition). The Cu(II)/HA and Cu(II)/HA/H 2 O 2 systems were the most effective reagents for the inactivation of planktonic cells. However, these systems were not effective in inactivating cells in biofilms on the RO membranes possibly due to the interactions of Cu(I) with extracellular polymeric substances (EPS), where biofilms were grown and treated in center for disease control (CDC) reactors. Different from the results using CDC reactors, in a pressurized cross-flow RO filtration unit, the Cu(II)/HA/H 2 O 2 treatment significantly inactivated biofilm cells formed on the RO membranes, successfully recovering the permeate flux reduced by the biofouling. The pretreatment of feed solutions by Cu(II)/HA and Cu(II)/HA/H 2 O 2 systems (applied before the biofilm formation) effectively mitigated the permeate flux decline by preventing the biofilm growth on the RO membranes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of proline residues in the dynamics of transmembrane helices: the case of bacteriorhodopsin.

PubMed

Perálvarez-Marín, Alex; Bourdelande, José-Luis; Querol, Enric; Padrós, Esteve

2006-01-01

Proline residues in transmembrane helices have been found to have important roles in the functioning of membrane proteins. Moreover, Pro residues occur with high frequency in transmembrane alpha-helices, as compared to alpha-helices for soluble proteins. Here, we report several properties of the bacteriorhodopsin mutants P50A (helix B), P91A (helix C) and P186A (helix F). Compared to wild type, strongly perturbed behaviour has been found for these mutants. In the resting state, increased hydroxylamine accessibility and altered Asp-85 pKa and light-dark adaptation were observed. On light activation, hydroxylamine accessibility was increased and proton transport activity, M formation kinetics and FTIR difference spectra of M and N intermediates showed clear distortions. On the basis of these alterations and the near identity of the crystalline structures of mutants with that of wild type, we conclude that the transmembrane proline residues of bacteriorhodopsin fulfil a dynamic role in both the resting and the light-activated states. Our results are consistent with the notion that mutation of Pro to Ala allows the helix to increase its flexibility towards the direction originally hindered by the steric clash between the ring Cgamma and the carbonyl O of the i-4 residue, at the same time decreasing the mobility towards the opposite direction. Due to their properties, transmembrane Pro residues may serve as transmission elements of conformational changes during the transport process. We propose that these concepts can be extended to other transmembrane proteins.

21 CFR 181.33 - Sodium nitrate and potassium nitrate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources of...

21 CFR 181.33 - Sodium nitrate and potassium nitrate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued by the U.S. Department of Agriculture for use as sources of...

21 CFR 181.33 - Sodium nitrate and potassium nitrate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrate and potassium nitrate. 181.33... nitrate and potassium nitrate. Sodium nitrate and potassium nitrate are subject to prior sanctions issued... potassium nitrite, in the production of cured red meat products and cured poultry products. [48 FR 1705, Jan...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 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...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 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...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 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...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 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...

Short-Term Effects of a High Nitrate Diet on Nitrate Metabolism in Healthy Individuals

PubMed Central

Bondonno, Catherine P.; Liu, Alex H.; Croft, Kevin D.; Ward, Natalie C.; Puddey, Ian B.; Woodman, Richard J.; Hodgson, Jonathan M.

2015-01-01

Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake. PMID:25774606

"Our Good Han Mothers": Observations from the Xinjiang Class at the Qingshan Superior Secondary School of Wuxi Municipality, Jiangsu Province

ERIC Educational Resources Information Center

Tao, Jiaqing; Yang, Xiaohu

2010-01-01

Instrumental to the successful running of the Xinjiang Classes are its teachers, many of whom are Han Chinese. This article explores the important roles teachers of the Xinjiang Class play in the lives of Xinjiang Class students inside and outside of the classroom. From homesickness, to hygiene, to scholastic endeavors, Han teacher-mothers…

Home artificial nutrition in advanced cancer.

PubMed

Pironi, L; Ruggeri, E; Tanneberger, S; Giordani, S; Pannuti, F; Miglioli, M

1997-11-01

Attitudes to home artificial nutrition (HAN) in cancer vary greatly from country to country. A 6-year prospective survey of the practice of HAN in advanced cancer patients applied by a hospital-at-home programme in an Italian health district was performed to estimate the utilization rate, to evaluate efficacy in preventing death from cachexia, maintaining patients at home without burdens and distress and improving patients' performance status, and to obtain information about costs. Patients were eligible for HAN when all the following were present: hypophagia; life expectancy 6 weeks or more, suitable patient and family circumstances; and verbal informed consent. From July 1990 to June 1996, 587 patients were evaluated; 164 were selected for HAN (135 enteral and 29 parenteral) and were followed until 31 December 1996. The incidence of HAN per million inhabitants was 18.4 in the first year of activity and 33.2-36.9 in subsequent years, being 4-10 times greater than rates reported by the Italian HAN registers. On 31 December 1996, 158 patients had died because of the disease and 6 were on treatment. Mean survival was 17.2 weeks for those on enteral nutrition and 12.2 weeks for those on parenteral nutrition. Prediction of survival was 72% accurate. 95 patients had undergone 155 readmissions to hospital, where they spent 15-23% of their survival time. Burdens due to HAN were well accepted by 124 patients, an annoyance or scarcely tolerable in the remainder. The frequency of major complications of parenteral nutrition was 0.67 per year for catheter sepsis and 0.16 per year for deep vein thrombosis. Karnofsky performance score increased in only 13 patients and body weight increased in 43. The fixed direct costs per patient-day (in European Currency Units) were 14.2 for the nutrition team, 18.2 for enteral nutrition and 61 for parenteral nutrition. The results indicate that definite entry criteria and local surveys are required for the correct use of HAN in advanced cancer patients, that HAN can be applied without causing additional burdens and distress, and that its costs are not higher than hospital costs.

Laser-treated electrospun fibers loaded with nano-hydroxyapatite for bone tissue engineering.

PubMed

Aragon, Javier; Navascues, Nuria; Mendoza, Gracia; Irusta, Silvia

2017-06-15

Core-shell polycaprolactone/polycaprolactone (PCL/PCL) and polycaprolactone/polyvinyl acetate (PCL/PVAc) electrospun fibers loaded with synthesized nanohydroxyapatite (HAn) were lased treated to create microporosity. The prepared materials were characterized by XRD, FTIR, TEM and SEM. Uniform and randomly oriented beadless fibrous structures were obtained in all cases. Fibers diameters were in the 150-300nm range. Needle-like HAn nanoparticles with mean diameters of 20nm and length of approximately 150nm were mostly encase inside the fibers. Laser treated materials present micropores with diameters in the range 70-120μm for PCL-HAn/PCL fibers and in the 50-90μm range for PCL-HAn/PVAC material. Only samples containing HAn presented bioactivity after incubation during 30days in simulated body fluid. All scaffolds presented high viability, very low mortality, and human osteoblast proliferation. Biocompatibility was increased by laser treatment due to the surface and porosity modification. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

NASA Astrophysics Data System (ADS)

Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

2016-08-01

To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (-17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.

Complementary feeding patterns among ethnic groups in rural western China.

PubMed

Qu, Peng-Fei; Zhang, Ya; Li, Jia-Mei; Zhang, Ruo; Yang, Jiao-Mei; Lei, Fang-Liang; Li, Shan-Shan; Liu, Dan-Meng; Dang, Shao-Nong; Yan, Hong

This study investigated complementary feeding practices among four ethnic groups (Han, Uygur, Tibetan, and Zhuang) based on a cross-sectional survey in rural western China. In 2005, a stratified multistage cluster random sampling method was used to recruit 9712 children (7411 Han, 1032 Uygur, 678 Tibetan, and 591 Zhuang) between 6 and 35 months of age and their mothers from 45 counties in 10 provinces (autonomous regions, municipalities) in western China. The rates of early introduction (before 6 months) of complementary foods in four ethnic groups (Han, Uygur, Tibetan, and Zhuang) were 71.30%, 95.95%, 82.40%, and 72.30%, respectively. The Infant and Child Feeding Index (ICFI) for Uygur and Tibetan children was lower than that for Han children at all age groups. Uygur children were more likely to have unqualified ICFI compared with Han children in a multivariate logistic regression (odds ratio (OR)=5.138, 95% confidence interval (CI): 4.340-6.084). A higher level of maternal education, greater family wealth, and the availability of complementary feeding educational materials decreased the likelihood of an unqualified ICFI. The nutritional status of children (Han, Tibetan, and Zhuang) with qualified ICFI was better than that for children with unqualified ICFI. Appropriate interventions are required to improve complementary feeding practices in rural western China.

Factors Related to Positive Changes in Perceived Health Status of Married Han Chinese and Korean-Chinese Women After Immigration to Korea.

PubMed

Asano, Kana; Ryu, Si Hyun; Chin, Meejung; Yoon, Jihyun

2016-11-01

This study aimed to compare factors related to changes in perceived health status of Han Chinese (traditional Chinese) and Korean-Chinese (Chinese nationals of Korean descent) women after immigration to Korea. During summer 2013, a survey was conducted with 151 Han and 158 Korean-Chinese women married to Korean men. Most of the respondents reported either no changes (82%) or positive changes (18%) in their perceived health status after immigration. The results of the multiple logistic regression analyses indicated healthy dietary behavior was related to positive changes in the perceived health status of both groups (odds ratio [OR] = 7.4 for Han Chinese; OR = 14.6 for Korean-Chinese). Among Han Chinese women, the length of residence in Korea and the change in perceived health status showed a negative relation (OR = 0.2). In contrast, their level of acculturation and health perception were positive (OR = 7.5). However, these results did not apply to the Korean-Chinese women. In conclusion, factors related to changes in perceived health status differed between the 2 groups although they shared healthy dietary behaviors as a common factor. Therefore, policies and programs aimed at promoting immigrant women's health should consider the differences between Han Chinese and Korean-Chinese. © 2016 APJPH.

Optimal cutoff of the waist-to-hip ratio for detecting cardiovascular risk factors among Han adults in Xinjiang.

PubMed

Li, Shuang-Shuang; Pan, Shuo; Ma, Yi-Tong; Yang, Yi-Ning; Ma, Xiang; Li, Xiao-Mei; Fu, Zhen-Yan; Xie, Xiang; Liu, Fen; Chen, You; Chen, Bang-Dang; Yu, Zi-Xiang; He, Chun-Hui; Zheng, Ying-Ying; Abudukeremu, Nuremanguli; Abuzhalihan, Jialin; Wang, Yong-Tao

2014-07-29

The optimal cutoff of the waist-to-hip ratio (WHR) among Han adults in Xinjiang, which is located in the center of Asia, is unknown. We aimed to examine the relationship between different WHRs and cardiovascular risk factors among Han adults in Xinjiang, and determine the optimal cutoff of the WHR. The Cardiovascular Risk Survey was conducted from October 2007 to March 2010. A total of 14618 representative participants were selected using a four-stage stratified sampling method. A total of 5757 Han participants were included in the study. The present statistical analysis was restricted to the 5595 Han subjects who had complete anthropometric data. The sensitivity, specificity, and distance on the receiver operating characteristic (ROC) curve in each WHR level were calculated. The shortest distance in the ROC curves was used to determine the optimal cutoff of the WHR for detecting cardiovascular risk factors. In women, the WHR was positively associated with systolic blood pressure, diastolic blood pressure, and serum concentrations of serum total cholesterol. The prevalence of hypertension and hypertriglyceridemia increased as the WHR increased. The same results were not observed among men. The optimal WHR cutoffs for predicting hypertension, diabetes, dyslipidemia and ≥ two of these risk factors for Han adults in Xinjiang were 0.92, 0.92, 0.91, 0.92 in men and 0.88, 0.89, 0.88, 0.89 in women, respectively. Higher cutoffs for the WHR are required in the identification of Han adults aged ≥ 35 years with a high risk of cardiovascular diseases in Xinjiang.

Assessing genome-wide copy number variation in the Han Chinese population.

PubMed

Lu, Jianqi; Lou, Haiyi; Fu, Ruiqing; Lu, Dongsheng; Zhang, Feng; Wu, Zhendong; Zhang, Xi; Li, Changhua; Fang, Baijun; Pu, Fangfang; Wei, Jingning; Wei, Qian; Zhang, Chao; Wang, Xiaoji; Lu, Yan; Yan, Shi; Yang, Yajun; Jin, Li; Xu, Shuhua

2017-10-01

Copy number variation (CNV) is a valuable source of genetic diversity in the human genome and a well-recognised cause of various genetic diseases. However, CNVs have been considerably under-represented in population-based studies, particularly the Han Chinese which is the largest ethnic group in the world. To build a representative CNV map for the Han Chinese population. We conducted a genome-wide CNV study involving 451 male Han Chinese samples from 11 geographical regions encompassing 28 dialect groups, representing a less-biased panel compared with the currently available data. We detected CNVs by using 4.2M NimbleGen comparative genomic hybridisation array and whole-genome deep sequencing of 51 samples to optimise the filtering conditions in CNV discovery. A comprehensive Han Chinese CNV map was built based on a set of high-quality variants (positive predictive value >0.8, with sizes ranging from 369 bp to 4.16 Mb and a median of 5907 bp). The map consists of 4012 CNV regions (CNVRs), and more than half are novel to the 30 East Asian CNV Project and the 1000 Genomes Project Phase 3. We further identified 81 CNVRs specific to regional groups, which was indicative of the subpopulation structure within the Han Chinese population. Our data are complementary to public data sources, and the CNV map may facilitate in the identification of pathogenic CNVs and further biomedical research studies involving the Han Chinese population. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

Kinetic Analysis of Haloacetonitrile Stability in Drinking Waters.

PubMed

Yu, Yun; Reckhow, David A

2015-09-15

Haloacetonitriles (HANs) are an important class of drinking water disinfection byproducts (DBPs) that are reactive and can undergo considerable transformation on time scales relevant to system distribution (i.e., from a few hours to a week or more). The stability of seven mono-, di-, and trihaloacetonitriles was examined under a variety of conditions including different pH levels and disinfectant doses that are typical of drinking water distribution systems. Results indicated that hydroxide, hypochlorite, and their protonated forms could react with HANs via nucleophilic attack on the nitrile carbon, forming the corresponding haloacetamides (HAMs) and haloacetic acids (HAAs) as major reaction intermediates and end products. Other stable intermediate products, such as the N-chloro-haloacetamides (N-chloro-HAMs), may form during the course of HAN chlorination. A scheme of pathways for the HAN reactions was proposed, and the rate constants for individual reactions were estimated. Under slightly basic conditions, hydroxide and hypochlorite are primary reactants and their associated second-order reaction rate constants were estimated to be 6 to 9 orders of magnitude higher than those of their protonated conjugates (i.e., neutral water and hypochlorous acid), which are much weaker but more predominant nucleophiles at neutral and acidic pHs. Developed using the estimated reaction rate constants, the linear free energy relationships (LFERs) summarized the nucleophilic nature of HAN reactions and demonstrated an activating effect of the electron withdrawing halogens on nitrile reactivity, leading to decreasing HAN stability with increasing degree of halogenation of the substituents, while subsequent shift from chlorine to bromine atoms has a contrary stabilizing effect on HANs. The chemical kinetic model together with the reaction rate constants that were determined in this work can be used for quantitative predictions of HAN concentrations depending on pH and free chlorine contact times (CTs), which can be applied as an informative tool by drinking water treatment and system management engineers to better control these emerging nitrogenous DBPs, and can also be significant in making regulatory decisions.

Comparison of Genetic Variants in Cancer-Related Genes between Chinese Hui and Han Populations

PubMed Central

Tian, Chaoyong; Chen, Zhiqiang; Ma, Xixian; Yang, Ming; Wang, Zhizhong; Dong, Ying; Yang, Ting; Yang, Wenjun

2015-01-01

Background The Chinese Hui population, as the second largest minority ethnic group in China, may have a different genetic background from Han people because of its unique demographic history. In this study, we aimed to identify genetic differences between Han and Hui Chinese from the Ningxia region of China by comparing eighteen single nucleotide polymorphisms in cancer-related genes. Methods DNA samples were collected from 99 Hui and 145 Han people from the Ningxia Hui Autonomous Region in China, and SNPs were detected using an improved multiplex ligase detection reaction method. Genotyping data from six 1000 Genomes Project population samples (99 Utah residents with northern and western European ancestry (CEU), 107 Toscani in Italy (TSI), 108 Yoruba in Ibadan (YRI), 61 of African ancestry in the southwestern US (ASW), 103 Han Chinese in Beijing (CHB), and 104 Japanese in Tokyo (JPT)) were also included in this study. Differences in the distribution of alleles among the populations were assessed using χ2 tests, and FST was used to measure the degree of population differentiation. Results We found that the genetic diversity of many SNPs in cancer-related genes in the Hui Chinese in Ningxia was different from that in the Han Chinese in Ningxia. For example, the allele frequencies of four SNPs (rs13361707, rs2274223, rs465498, and rs753955) showed different genetic distributions (p<0.05) between Chinese Ningxia Han and Chinese Ningxia Hui. Five SNPs (rs730506, rs13361707, rs2274223, rs465498 and rs753955) had different FST values (FST >0.000) between the Hui and Han populations. Conclusions These results suggest that some SNPs associated with cancer-related genes vary among different Chinese ethnic groups. We suggest that population differences should be carefully considered in evaluating cancer risk and prognosis as well as the efficacy of cancer therapy. PMID:26683024

Comparison of Genetic Variants in Cancer-Related Genes between Chinese Hui and Han Populations.

PubMed

Tian, Chaoyong; Chen, Zhiqiang; Ma, Xixian; Yang, Ming; Wang, Zhizhong; Dong, Ying; Yang, Ting; Yang, Wenjun

2015-01-01

The Chinese Hui population, as the second largest minority ethnic group in China, may have a different genetic background from Han people because of its unique demographic history. In this study, we aimed to identify genetic differences between Han and Hui Chinese from the Ningxia region of China by comparing eighteen single nucleotide polymorphisms in cancer-related genes. DNA samples were collected from 99 Hui and 145 Han people from the Ningxia Hui Autonomous Region in China, and SNPs were detected using an improved multiplex ligase detection reaction method. Genotyping data from six 1000 Genomes Project population samples (99 Utah residents with northern and western European ancestry (CEU), 107 Toscani in Italy (TSI), 108 Yoruba in Ibadan (YRI), 61 of African ancestry in the southwestern US (ASW), 103 Han Chinese in Beijing (CHB), and 104 Japanese in Tokyo (JPT)) were also included in this study. Differences in the distribution of alleles among the populations were assessed using χ2 tests, and FST was used to measure the degree of population differentiation. We found that the genetic diversity of many SNPs in cancer-related genes in the Hui Chinese in Ningxia was different from that in the Han Chinese in Ningxia. For example, the allele frequencies of four SNPs (rs13361707, rs2274223, rs465498, and rs753955) showed different genetic distributions (p<0.05) between Chinese Ningxia Han and Chinese Ningxia Hui. Five SNPs (rs730506, rs13361707, rs2274223, rs465498 and rs753955) had different FST values (FST>0.000) between the Hui and Han populations. These results suggest that some SNPs associated with cancer-related genes vary among different Chinese ethnic groups. We suggest that population differences should be carefully considered in evaluating cancer risk and prognosis as well as the efficacy of cancer therapy.

Effect of zoledronic acid therapy on postmenopausal osteoporosis between the Uighur and Han population in Xinjiang: An open-label, long-term safety and efficacy study.

PubMed

Xu, W; Xiang, C; Wang, H; Yuan, H; Zhao, X; Xiao, X

2018-06-01

Postmenopausal osteoporosis is becoming an urgent health problem in China. A once-yearly infusion of zoledronic acid can be very effective for the treatment of postmenopausal osteoporosis in significantly reducing the risk of hip, vertebral and other fractures. This study aimed to investigate zoledronic acid treatment on postmenopausal osteoporosis in Uighur and Han patients in Xinjiang province, China. A self-controlled and prospective trial design was adopted. A total of 155 Uighur and 151 Han patients were enrolled. All subjects received an intravenous infusion of zoledronic acid (5 mg) at day 0 (baseline) and at 12 months. Patients were followed up for 24 months; the bone mineral density (BMD) of the left total hip and L1-L4 vertebrae was measured at day 0 and at 24 months. BMD was significantly higher after zoledronic acid treatment compared with baseline levels in all patients, as assessed at 24 months. Moreover, the BMD of left total hip increased with 2.7% in the Han group was significantly higher than that of the Uighur group with 1.4% (left total hip, 95% CI: 2.6% to 2.8% in Han group vs 1.2% to 1.4% in Uighur group). The BMD of L1-L4 vertebrae increased with 2.2% in the Han group was significantly higher than that of the Uighur group with 1.6% (L1-L4 vertebrae, 95% CI, 2.0% to 2.4% in Han group vs 1.4% to 1.7% in Uighur group); P < .001. There was no significant difference in drug-related adverse effects between the two groups (P > .05). Zoledronic acid appears to be more effective in postmenopausal osteoporosis in Han than in Uighur subjects. The reasons for this require further investigation. © 2017 John Wiley & Sons Ltd.

Association of the TRIB1 tribbles homolog 1 gene rs17321515 A>G polymorphism and serum lipid levels in the Mulao and Han populations

PubMed Central

2011-01-01

Background The association of rs17321515 single nucleotide polymorphism (SNP) near TRIB1 gene and serum lipid profiles has never been studied in the Chinese population. Therefore, the present study was undertaken to detect the association of rs17321515 SNP and several environmental factors on serum lipid levels in the Mulao and Han populations. Methods A total of 639 unrelated subjects of Mulao nationality and 644 participants of Han nationality were randomly selected from our previous stratified randomized cluster samples. Genotypes of the TRIB1 rs17321515 A>G SNP were determined via polymerase chain reaction and restriction fragment length polymorphism, and then confirmed by direct sequencing. Results Serum apolipoprotein (Apo) B levels were higher in Mulao than in Han (P < 0.05). There were no differences in the genotypic and allelic frequencies between the two ethnic groups (P > 0.05). High- and low-density lipoprotein cholesterol (HDL-C and LDL-C) levels in Han were different among the genotypes (P < 0.05 for each), the subjects with AG/GG genotypes had higher HDL-C and LDL-C levels than the subjects with AA genotype. Total cholesterol (TC), HDL-C, LDL-C, ApoA1 and ApoB levels in Han males were different among the genotypes (P < 0.05-0.001), the G carriers had higher TC, HDL-C, LDL-C, ApoA1 and ApoB levels than the G noncarriers. HDL-C levels in Mulao males were different among the genotypes (P < 0.05), the G carriers had lower HDL-C levels than the G noncarriers. Serum HDL-C and LDL-C levels in both ethnic groups and TG levels in Han were correlated with the genotypes or alleles (P < 0.05-0.01). TG and HDL-C levels in Mulao males and TG, HDL-C, LDL-C and ApoA1 levels in Han males were correlated with genotypes or alleles (P < 0.05-0.001). TG and ApoA1 levels in Han females were associated with genotypes (P < 0.05 for each). Serum lipid parameters were also associated with several environmental factors in both ethnic groups. Conclusions The associations of TRIB1 rs17321515 SNP and serum lipid levels are different between the Mulao and Han populations. These discrepancies might partly result from different TRIB1 gene-environmental interactions in both ethnic groups. PMID:22145581

Molecular Components of Nitrate and Nitrite Efflux in Yeast

PubMed Central

Cabrera, Elisa; González-Montelongo, Rafaela; Giraldez, Teresa; de la Rosa, Diego Alvarez

2014-01-01

Some eukaryotes, such as plant and fungi, are capable of utilizing nitrate as the sole nitrogen source. Once transported into the cell, nitrate is reduced to ammonium by the consecutive action of nitrate and nitrite reductase. How nitrate assimilation is balanced with nitrate and nitrite efflux is unknown, as are the proteins involved. The nitrate assimilatory yeast Hansenula polymorpha was used as a model to dissect these efflux systems. We identified the sulfite transporters Ssu1 and Ssu2 as effective nitrate exporters, Ssu2 being quantitatively more important, and we characterize the Nar1 protein as a nitrate/nitrite exporter. The use of strains lacking either SSU2 or NAR1 along with the nitrate reductase gene YNR1 showed that nitrate reductase activity is not required for net nitrate uptake. Growth test experiments indicated that Ssu2 and Nar1 exporters allow yeast to cope with nitrite toxicity. We also have shown that the well-known Saccharomyces cerevisiae sulfite efflux permease Ssu1 is also able to excrete nitrite and nitrate. These results characterize for the first time essential components of the nitrate/nitrite efflux system and their impact on net nitrate uptake and its regulation. PMID:24363367

Nitrate and periplasmic nitrate reductases

PubMed Central

Sparacino-Watkins, Courtney; Stolz, John F.; Basu, Partha

2014-01-01

The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types – periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed. PMID:24141308

Space and Missile Systems Center Compliance Specifications and Standards

DTIC Science & Technology

2015-07-31

Mike Jensen United Launch Alliance mike.jensen@ulalaunch.com Hans Koenigsmann SpaceX Hans.Koenigsmann@ spacex . com APPROVED BY_________________________________________________________________ DATE_______________ (AF OFFICE)

21 CFR 181.33 - Sodium nitrate and potassium nitrate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium... nitrite, with or without sodium or potassium nitrite, in the production of cured red meat products and...

21 CFR 181.33 - Sodium nitrate and potassium nitrate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrate and potassium nitrate. 181.33...-Sanctioned Food Ingredients § 181.33 Sodium nitrate and potassium nitrate. Sodium nitrate and potassium... nitrite, with or without sodium or potassium nitrite, in the production of cured red meat products and...

Arabidopsis Nitrate Transporter NRT1.9 Is Important in Phloem Nitrate Transport[W][OA

PubMed Central

Wang, Ya-Yun; Tsay, Yi-Fang

2011-01-01

This study of the Arabidopsis thaliana nitrate transporter NRT1.9 reveals an important function for a NRT1 family member in phloem nitrate transport. Functional analysis in Xenopus laevis oocytes showed that NRT1.9 is a low-affinity nitrate transporter. Green fluorescent protein and β-glucuronidase reporter analyses indicated that NRT1.9 is a plasma membrane transporter expressed in the companion cells of root phloem. In nrt1.9 mutants, nitrate content in root phloem exudates was decreased, and downward nitrate transport was reduced, suggesting that NRT1.9 may facilitate loading of nitrate into the root phloem and enhance downward nitrate transport in roots. Under high nitrate conditions, the nrt1.9 mutant showed enhanced root-to-shoot nitrate transport and plant growth. We conclude that phloem nitrate transport is facilitated by expression of NRT1.9 in root companion cells. In addition, enhanced root-to-shoot xylem transport of nitrate in nrt1.9 mutants points to a negative correlation between xylem and phloem nitrate transport. PMID:21571952

Stereoselective isoxazolidine synthesis via copper-catalyzed alkene aminooxygenation.

PubMed

Karyakarte, Shuklendu D; Smith, Thomas P; Chemler, Sherry R

2012-09-07

Isoxazolidines are useful in organic synthesis, drug discovery, and chemical biology endeavors. A new stereoselective synthesis of methyleneoxy-substituted isoxazolidines is disclosed. The method involves copper-catalyzed aminooxygenation/cyclization of N-sulfonyl-O-butenyl hydroxylamines in the presence of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical (TEMPO) and O(2) and provides substituted isoxazolidines in excellent yields and diastereoselectivities. We also demonstrate selective mono N-O reduction followed by oxidation of the remaining N-O bond to reveal a 2-amino-γ-lactone. Reduction of the γ-lactone reveals the corresponding aminodiol.

A catalytic tethering strategy: simple aldehydes catalyze intermolecular alkene hydroaminations.

PubMed

MacDonald, Melissa J; Schipper, Derek J; Ng, Peter J; Moran, Joseph; Beauchemin, André M

2011-12-21

Herein we describe a catalytic tethering strategy in which simple aldehyde precatalysts enable, through temporary intramolecularity, room-temperature intermolecular hydroamination reactivity and the synthesis of vicinal diamines. The catalyst allows the formation of a mixed aminal from an allylic amine and a hydroxylamine, resulting in a facile intramolecular hydroamination event. The promising enantioselectivities obtained with a chiral aldehyde also highlight the potential of this catalytic tethering approach in asymmetric catalysis and demonstrate that efficient enantioinduction relying only on temporary intramolecularity is possible. © 2011 American Chemical Society

Nitrate analogs as attractants for soybean cyst nematode.

PubMed

Hosoi, Akito; Katsuyama, Tsutomu; Sasaki, Yasuyuki; Kondo, Tatsuhiko; Yajima, Shunsuke; Ito, Shinsaku

2017-08-01

Soybean cyst nematode (SCN) Heterodera glycines Ichinohe, a plant parasite, is one of the most serious pests of soybean. In this paper, we report that SCN is attracted to nitrate and its analogs. We performed attraction assays to screen for novel attractants for SCN and found that nitrates were attractants for SCN and SCN recognized nitrate gradients. However, attraction of SCN to nitrates was not observed on agar containing nitrate. To further elucidate the attraction mechanism in SCN, we performed attraction assays using nitrate analogs ([Formula: see text], [Formula: see text], [Formula: see text]). SCN was attracted to all nitrate analogs; however, attraction of SCN to nitrate analogs was not observed on agar containing nitrate. In contrast, SCN was attracted to azuki root, irrespective of presence or absence of nitrate in agar media. Our results suggest that the attraction mechanisms differ between plant-derived attractant and nitrate.

The Impact of the North Korean Nuclear Crisis on Northeast Asia

DTIC Science & Technology

2007-12-01

NORTH KOREAN NUCLEAR CRISIS ON NORTHEAST ASIA by Jonghun Han December 2007 Thesis Advisor: Edward A. Olsen Thesis Co-advisor: Robert E...COVERED Master’s Thesis 4. TITLE AND SUBTITLE The Impact of the North Korean Nuclear Crisis on Northeast Asia 6. AUTHOR(S) Jonghun Han 5...distribution is unlimited THE IMPACT OF THE NORTH KOREAN NUCLEAR CRISIS ON NORTHEAST ASIA Jonghun Han Captain, ROK Army B.A., Korea Military

Konrad Adenauer’s Military Advisors

DTIC Science & Technology

1989-02-13

Ausgabe. Hans-Peter Schwarz and 45 Rudolf Morsey, Hg. Vol. 1, Briefe 1945-1947 hg. v. Hans Peter Mensing. Berlin: Siedler Verlag, 1983. Vol. 2, Briefe 1949...Dietrich, Rudolf Morsey and Hans-Peter Schwarz, ed. Quellen zur Geschichte des Parlarnentarismus und der politischen Partein. Bd. 3, Auftakt zur Ara...New York: Penguin, 1982. Steiner , Jirg. European Democracies. New York: Longman, 1986. Taylor, A.J.P. The Origens of the Second World War. 2d. ed. New

Bioactivation of organic nitrates and the mechanism of nitrate tolerance.

PubMed

Klemenska, Emila; Beresewicz, Andrzej

2009-01-01

Organic nitrates, such as nitroglycerin, are commonly used in the therapy of cardiovascular disease. Long-term therapy with these drugs, however, results in the rapid development of nitrate tolerance, limiting their hemodynamic and anti-ischemic efficacy. In addition, nitrate tolerance is associated with the expression of potentially deleterious modifications such as increased oxidative stress, endothelial dysfunction, and sympathetic activation. In this review we discuss current concepts regarding the mechanisms of organic nitrate bioactivation, nitrate tolerance, and nitrate-mediated oxidative stress and endothelial dysfunction. We also examine how hydralazine may prevent nitrate tolerance and related endothelial dysfunction.

Respiratory Nitrate Ammonification by Shewanella oneidensis MR-1▿

PubMed Central

Cruz-García, Claribel; Murray, Alison E.; Klappenbach, Joel A.; Stewart, Valley; Tiedje, James M.

2007-01-01

Anaerobic cultures of Shewanella oneidensis MR-1 grown with nitrate as the sole electron acceptor exhibited sequential reduction of nitrate to nitrite and then to ammonium. Little dinitrogen and nitrous oxide were detected, and no growth occurred on nitrous oxide. A mutant with the napA gene encoding periplasmic nitrate reductase deleted could not respire or assimilate nitrate and did not express nitrate reductase activity, confirming that the NapA enzyme is the sole nitrate reductase. Hence, S. oneidensis MR-1 conducts respiratory nitrate ammonification, also termed dissimilatory nitrate reduction to ammonium, but not respiratory denitrification. PMID:17098906

An interview with Mark G. Hans

PubMed Central

Bolognese, Ana Maria; Palomo, Juan Martin; Miyashita, Kunihiko; Nojima, Lincoln Issamu; Nojima, Matilde da Cunha Gonçalves

2014-01-01

It is a great honor to conduct an interview with Professor Mark G. Hans, after following his outstanding work ahead of the Bolton-Brush Growth Study Center and the Department of Orthodontics at the prestigious Case Western Reserve School of Dental Medicine (CWRU) in Cleveland, Ohio. Born in Berea, Ohio, Professor Mark Hans attended Yale University in New Haven, CT, and earned his Bachelor of Science Degree in Chemistry. Upon graduation, Dr. Hans received his DDS and Masters Degree of Science in Dentistry with specialty certification in Orthodontics at Case Western Reserve University. During his education, Dr. Hans' Master's Thesis won the Harry Sicher Award for Best Research by an Orthodontic Student and being granted a Presidential Teaching Fellowship. As one of the youngest doctors ever certified by the American Board of Orthodontics, Dr. Hans continues to maintain his board certification. He has worked through academics on a variety of research interests, that includes the demographics of orthodontic practice, digital radiographic data, dental and craniofacial genetics, as obstructive sleep apnea syndrome, with selected publications in these fields. One of his noteworthy contributions to the orthodontic literature came along with Dr. Donald Enlow on the pages of "Essentials of Facial Growth", being reference on the study of craniofacial growth and development. Dr. Mark Hans's academic career is linked to CWRU, recognized as the renowned birthplace of research on craniofacial growth and development, where the classic Bolton-Brush Growth Study was historically set. Today, Dr. Hans is the Director of The Bolton-Brush Growth Study Center, performing, with great skill and dedication, the handling of the larger longitudinal sample of bone growth study. He is Associate Dean for Graduate Studies, Professor and Chairman of the Department of Orthodontics, working in clinical and theoretical activities with students of the Undergraduate Course from the School of Dental Medicine and residents in the Department of Orthodontics at CWRU. Part of his clinical practice at the university is devoted to the treatment of craniofacial anomalies and to special needs patients. Prof. Mark Hans has been wisely conducting the Joint Cephalometric Experts Group (JCEG) since 2008, held at the School of Dental Medicine (CWRU). He coordinates a team composed of American, Asian, Brazilian and European researchers and clinicians, working on the transition from 2D cephalometrics to 3D cone beam imaging as well as 3D models for diagnosis, treatment planning and assessment of orthodontic outcomes. Dr. Hans travels to different countries to give lectures on his fields of interest. Besides, he still maintains a clinical orthodontic practice at his private office. In every respect, Dr. Hans coordinates all activities with particular skill and performance. Married to Susan, they have two sons, Thomas and Jack and one daughter, Sarah and he enjoys playing jazz guitar for family and friends. Matilde da Cunha Gonçalves Nojima PMID:25162563

Nitrate transport in the cyanobacterium Anacystis nidulans R2. Kinetic and energetic aspects.

PubMed Central

Rodríguez, R; Lara, C; Guerrero, M G

1992-01-01

Nitrate transport has been studied in the cyanobacterium Anacystis nidulans R2 by monitoring intracellular nitrate accumulation in intact cells of the mutant strain FM6, which lacks nitrate reductase activity and is therefore unable to reduce the transported nitrate. Kinetic analysis of nitrate transport as a function of external nitrate concentration revealed apparent substrate inhibition, with a peak velocity at 20-25 microM-nitrate. A Ks (NO3-) of 1 microM was calculated. Nitrate transport exhibited a stringent requirement for Na+. Neither Li+ nor K+ could substitute for Na+. Monensin depressed nitrate transport in a concentration-dependent manner, inhibition being more than 60% at 2 microM, indicating that the Na(+)-dependence of active nitrate transport relies on the maintenance of a Na+ electrochemical gradient. The operation of an Na+/NO3- symport system is suggested. Nitrite behaved as an effective competitive inhibitor of nitrate transport, with a Ki (NO2-) of 3 microM. The time course of nitrite inhibition of nitrate transport was consistent with competitive inhibition by mixed alternative substrates. Nitrate and nitrite might be transported by the same carrier. PMID:1554347

Relation of nitrate concentrations to baseflow in the Raccoon River, Iowa

USGS Publications Warehouse

Schilling, K.E.; Lutz, D.S.

2004-01-01

Excessive nitrate-nitrogen (nitrate) export from the Raccoon River in west central Iowa is an environmental concern to downstream receptors. The 1972 to 2000 record of daily streamflow and the results from 981 nitrate measurements were examined to describe the relation of nitrate to streamflow in the Raccoon River. No long term trends in streamflow and nitrate concentrations were noted in the 28-year record. Strong seasonal patterns were evident in nitrate concentrations, with higher concentrations occurring in spring and fall. Nitrate concentrations were linearly related to streamflow at daily, monthly, seasonal, and annual time scales. At all time scales evaluated, the relation was improved when baseflow was used as the discharge variable instead of total streamflow. Nitrate concentrations were found to be highly stratified according to flow, but there was little relation of nitrate to streamflow within each flow range. Simple linear regression models developed to predict monthly mean nitrate concentrations explained as much as 76 percent of the variability in the monthly nitrate concentration data for 2001. Extrapolation of current nitrate baseflow relations to historical conditions in the Raccoon River revealed that increasing baseflow over the 20th century could account for a measurable increase in nitrate concentrations.

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(-)-myrtenol nitrate.

PubMed

Bew, Sean P; Hiatt-Gipson, Glyn D; Mills, Graham P; Reeves, Claire E

2016-01-01

Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a 'halide for nitrate' substitution. Employing readily available starting materials, reagents and Horner-Wadsworth-Emmons chemistry the synthesis of easily separable, synthetically versatile 'key building blocks' (E)- and (Z)-3-methyl-4-chlorobut-2-en-1-ol as well as (E)- and (Z)-1-((2-methyl-4-bromobut-2-enyloxy)methyl)-4-methoxybenzene has been achieved using cheap, 'off the shelf' materials. Exploiting their reactivity we have studied their ability to undergo an 'allylic halide for allylic nitrate' substitution reaction which we demonstrate generates (E)- and (Z)-3-methyl-4-hydroxybut-2-enyl nitrate, and (E)- and (Z)-2-methyl-4-hydroxybut-2-enyl nitrates ('isoprene nitrates') in 66-80% overall yields. Using NOESY experiments the elucidation of the carbon-carbon double bond configuration within the purified isoprene nitrates has been established. Further exemplifying our 'halide for nitrate' substitution chemistry we outline the straightforward transformation of (1R,2S)-(-)-myrtenol bromide into the previously unknown monoterpene nitrate (1R,2S)-(-)-myrtenol nitrate.

Plasma nitrate and nitrite are increased by a high nitrate supplement, but not by high nitrate foods in older adults

PubMed Central

Miller, Gary D.; Marsh, Anthony P.; Dove, Robin W.; Beavers, Daniel; Presley, Tennille; Helms, Christine; Bechtold, Erika; King, S. Bruce; Kim-Shapiro, Daniel

2012-01-01

Little is known about the effect of dietary nitrate on the nitrate/nitrite/NO (nitric oxide) cycle in older adults. We examined the effect of a 3-day control diet vs. high nitrate diet, with and without a high nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics, and blood pressure using a randomized four period cross-over controlled design. We hypothesized that the high nitrate diet would show higher levels of plasma nitrate/nitrite and blood pressure compared to the control diet, which would be potentiated by the supplement. Participants were eight normotensive older men and women (5 female, 3 male, 72.5±4.7 yrs) with no overt disease or medications that affect NO metabolism. Plasma nitrate and nitrite levels and blood pressure were measured prior to and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet+supplement (p<0.001 and =0.017 for nitrate and nitrite, respectively) and high nitrate diet+supplement (p=0.001 and 0.002), but not for control diet (p=0.713 and 0.741) or high nitrate diet (p=0.852 and 0.500). Blood pressure decreased from the morning baseline measure to the three 2 hr post-meal follow-up time-points for all treatments, but there was no main effect for treatment. In healthy older adults, a high nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction. PMID:22464802

The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150.

PubMed

Wang, L; Stuart, M E; Lewis, M A; Ward, R S; Skirvin, D; Naden, P S; Collins, A L; Ascott, M J

2016-01-15

Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Influence of the South-North Water Diversion Project and the mitigation projects on the water quality of Han River.

PubMed

Zhu, Y P; Zhang, H P; Chen, L; Zhao, J F

2008-11-15

Situated in the central part of China, the Han River Basin is undergoing rapid social and economic development with some human interventions to be made soon which will profoundly influence the water environment of the basin. The integrated MIKE 11 model system comprising of a rainfall-runoff model (NAM), a non-point load evaluation model (LOAD), a hydrodynamic model (MIKE 11 HD) and a water quality model (ECOLab) was applied to investigate the impact of the Middle Route of the South-North Water Diversion Project on the Han River and the effectiveness of the 2 proposed mitigation projects, the 22 wastewater treatment plants (WWTPs) and the Yangtze-Han Water Diversion Project. The study concludes that business as usual will lead to a continuing rapid deterioration of the water quality of the Han River. Implementation of the Middle Route of the South-North Water Diversion Project in 2010 will bring disastrous consequence in the form of the remarkably elevated pollution level and high risk of algae bloom in the middle and lower reaches. The proposed WWTPs will merely lower the pollution level in the reach by around 10%, while the Yangtze-Han Water Diversion Project can significantly improve the water quality in the downstream 200-km reach. The results reveal that serious water quality problem will emerge in the middle reach between Xiangfan and Qianjiang in the future. Implementation of the South-North Water Diversion Project (phase II) in 2030 will further exacerbate the problem. In order to effectively improve the water quality of the Han River, it is suggested that nutrient removal processes should be adopted in the proposed WWTPs, and the pollution load from the non-point sources, especially the load from the upstream Henan Province, should be effectively controlled.

Asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering for stability comparison of virus-like particles in different solution environments.

PubMed

Chen, Yi; Zhang, Yan; Zhou, Yuefang; Luo, Jian; Su, Zhiguo

2016-06-08

The stabilities of two commercially available virus like particles, CHO-HBsAg expressed by Chinese hamster ovary (CHO) cells and Hans-HBsAg expressed by Hansenula polymorpha (Hans), were compared using AF4-MALLS under different treatment processes. The initial molecular weight and hydrodynamic diameter of CHO-HBsAg measured with AF4-MALLS were 4727kDa and 29.4nm, while those of Hans-HBsAg were 3039kDa and 22.8nm respectively. In salt solution of 2M ammonium sulfate, the molecular weight and size of CHO-HBsAg had little change, and its antigenicity remained 95%, while those of Hans-HBsAg changed greatly, resulting in aggregation and 75% antigenicity loss. In freeze-thaw operations, Hans-HBsAg aggregated heavily. Most of the aggregates precipitated and the rest soluble aggregates reached 10(5)-10(6)kDa in molecular weight. The antigenicity of Hans-HBsAg decreased to 26.9% after five freeze-thaw cycles. For CHO-HBsAg, there was no obvious aggregation in freeze-thaw, and the antigenicity retained above 98%. In heating process, Hans-HBsAg gradually aggregated to large particles with temperature and the antigenicity decreased to 10% when the temperature reached 80°C. In contrast, CHO-HBsAg would not aggregate with temperature, remained 92% antigenicity at 80°C. The study demonstrated that CHO-HBsAg appeared to be a superior vaccine antigen in term of particle stability and constant antigenicity, which are important in production, transportation and storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimal cutoff of the waist-to-hip ratio for detecting cardiovascular risk factors among Han adults in Xinjiang

PubMed Central

2014-01-01

Background The optimal cutoff of the waist-to-hip ratio (WHR) among Han adults in Xinjiang, which is located in the center of Asia, is unknown. We aimed to examine the relationship between different WHRs and cardiovascular risk factors among Han adults in Xinjiang, and determine the optimal cutoff of the WHR. Methods The Cardiovascular Risk Survey was conducted from October 2007 to March 2010. A total of 14618 representative participants were selected using a four-stage stratified sampling method. A total of 5757 Han participants were included in the study. The present statistical analysis was restricted to the 5595 Han subjects who had complete anthropometric data. The sensitivity, specificity, and distance on the receiver operating characteristic (ROC) curve in each WHR level were calculated. The shortest distance in the ROC curves was used to determine the optimal cutoff of the WHR for detecting cardiovascular risk factors. Results In women, the WHR was positively associated with systolic blood pressure, diastolic blood pressure, and serum concentrations of serum total cholesterol. The prevalence of hypertension and hypertriglyceridemia increased as the WHR increased. The same results were not observed among men. The optimal WHR cutoffs for predicting hypertension, diabetes, dyslipidemia and ≥ two of these risk factors for Han adults in Xinjiang were 0.92, 0.92, 0.91, 0.92 in men and 0.88, 0.89, 0.88, 0.89 in women, respectively. Conclusions Higher cutoffs for the WHR are required in the identification of Han adults aged ≥ 35 years with a high risk of cardiovascular diseases in Xinjiang. PMID:25074400

An EPAS1 haplotype is associated with high altitude polycythemia in male Han Chinese at the Qinghai-Tibetan plateau.

PubMed

Chen, Yu; Jiang, Chunhua; Luo, Yongjun; Liu, Fuyu; Gao, Yuqi

2014-12-01

Hemoglobin concentration at high altitude is considered an important marker of high altitude adaptation, and native Tibetans in the Qinghai-Tibetan plateau show lower hemoglobin concentrations than Han people who have emigrated from plains areas. Genetic studies revealed that EPAS1 plays a key role in high altitude adaptation and is associated with the low hemoglobin concentration in Tibetans. Three single nucleotide polymorphisms (rs13419896, rs4953354, rs1868092) of noncoding regions in EPAS1 exhibited significantly different allele frequencies in the Tibetan and Han populations and were associated with low hemoglobin concentrations in Tibetans. To explore the hereditary basis of high altitude polycythemia (HAPC) and investigate the association between EPAS1 and HAPC in the Han population, these 3 single nucleotide polymorphisms were assessed in 318 male Han Chinese HAPC patients and 316 control subjects. Genotyping was performed by high resolution melting curve analysis. The G-G-G haplotype of rs13419896, rs4953354, and rs1868092 was significantly more frequent in HAPC patients than in control subjects, whereas no differences in the allele or genotype frequencies of the 3 single nucleotide polymorphisms were found between HAPC patients and control subjects. Moreover, genotypes of rs1868092 (AA) and rs4953354 (GG) that were not observed in the Chinese Han in the Beijing population were found at frequencies of 1.6% and 0.9%, respectively, in our study population of HAPC patients and control subjects. Carriers of this EPAS1 haplotype (G-G-G, rs13419896, rs4953354, and rs1868092) may have a higher risk for HAPC. These results may contribute to a better understanding of the pathogenesis of HAPC in the Han population. Copyright © 2014 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Home artificial nutrition: an update seven years after the regional regulation.

PubMed

Santarpia, Lidia; Pagano, Maria Carmen; Pasanisi, Fabrizio; Contaldo, Franco

2014-10-01

Home Artificial Nutrition (HAN) is a well established extra-hospital therapy, contributing to decreased health care costs, by reducing the number and length of hospitalizations. The knowledge of the epidemiology of HAN helps plan health-care funding and in analyze the factors that can improve HAN service. An update on the prevalence of Home Artificial Nutrition (HAN) in the Campania region (Southern Italy) and patients clinical characteristics has been regularly carried out in the past seven years after a specific regional regulation issued in 2005. Total number of patients on HAN has increased from 355 in April 2005 to 1165 in April 2012 (+228.2%); in particular, patients on Home Parenteral Nutrition (HPN) increased from 156 in April 2005 to 306 in April 2012 (+96.2%) and patients on Home Enteral Nutrition (HEN) from 199 to 838 (+321.1%) respectively. HEN/HPN ratio in adults has changed from 1.3/1 in April 2005 to 2.7/1 in April 2012, gradually nearing the expected national mean ratio of 5/1 as observed in the 2005 national survey. The specific regional regulation in Campania has contributed to increase the prescription of HAN and to ameliorate its indications; in particular, through the years, HEN is gradually nearing national standards. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer

PubMed Central

Kou, Meng; Tang, Zhonghou; Zhang, Aijun; Li, Hongmin; Wei, Meng

2017-01-01

Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index. PMID:29253886

Analysis of CYP3A4 genetic polymorphisms in Han Chinese.

PubMed

Zhou, Qing; Yu, Xiaomin; Shu, Chang; Cai, Yimei; Gong, Wei; Wang, Xumin; Wang, Duen-mei; Hu, Songnian

2011-06-01

Our study aimed to comprehensively investigate the genetic polymorphisms of CYP3A4 in Han Chinese. We sequenced the gene regions of CYP3A4, including its promoter, exons, surrounding introns and 3' untranslated region (3'UTR), from 100 unrelated-healthy Han Chinese individuals. We detected 11 SNPs, three of which are novel. According to in silico functional prediction of novel variants, 20148 A>G in exon 10, resulting in substitution of Tyr319 with Cys (CYP3A4*21), may induce dramatic alteration of protein conformation, and 26908 G>A in 3'UTR may disrupt post-transcriptional regulation. We identified five alleles in Han Chinese, the allele frequencies of CYP3A4*1, *5, *6, *18 and *21 are 97, 0.5, 1, 1 and 0.5%, respectively. Haplotype inference revealed 14 haplotypes, of which the major haplotype CYP3A4*1A constitutes 59% of the total chromosomes. We also examined the possible role of natural selection in shaping the variation of CYP3A4 and confirmed a trend, consistent with the action of positive selection. We systematically screened the genetic polymorphisms of CYP3A4 in Han Chinese, highlighted possible functional impairment of the novel allele and summarized the distinct allele and haplotype frequency distribution, with an emphasis on detecting the footprint of recent positive selection on the CYP3A4 gene in Han Chinese.

Source Areas of Water and Nitrate in a Peatland Catchment, Minnesota, USA

NASA Astrophysics Data System (ADS)

Sebestyen, S. D.

2017-12-01

In nitrogen polluted forests, stream nitrate concentrations increase and some unprocessed atmospheric nitrate may be transported to streams during stormflow events. This understanding has emerged from forests with upland mineral soils. In contrast, catchments with northern peatlands may have both upland soils and lowlands with deep organic soils, each with unique effects on nitrate transport and processing. While annual budgets show nitrate yields to be relatively lower from peatland than upland-dominated catchments, little is known about particular runoff events when stream nitrate concentrations have been higher (despite long periods with little or no nitrate in outlet streams) or the reasons why. I used site knowledge and expansive/extensive monitoring at the Marcell Experimental Forest in Minnesota, along with a targeted 2-year study to determine landscape areas, water sources, and nitrate sources that affected stream nitrate variation in a peatland catchment. I combined streamflow, upland runoff, snow amount, and frost depth data from long-term monitoring with nitrate concentration, yield, and isotopic data to show that up to 65% of stream nitrate during snowmelt of 2009 and 2010 was unprocessed atmospheric nitrate. Up to 46% of subsurface runoff from upland soils during 2009 was unprocessed atmospheric nitrate, which shows the uplands to be a stream nitrate source during 2009, but not during 2010 when upland runoff concentrations were below the detection limit. Differences are attributable to variations in water and nitrate sources. Little snow (a nitrate source), less upland runoff relative to peatland runoff, and deeper soil frost in the peatland caused a relatively larger input of nitrate from the uplands to the stream during 2009 and the peatland to the stream during 2010. Despite the near-absence of stream nitrate during much of rest of the year, these findings show an important time when nitrate transport affected downstream aquatic ecosystems, reasons why nitrate was transported, and that atmospheric nitrate pollution had a direct effect on a stream in a peatland catchment. Furthermore, this work illustrates how long-term monitoring when coupled with shorter-duration studies allows contemporary questions to be addressed within legacy catchment studies.

Pseudo-constitutivity of nitrate-responsive genes in nitrate reductase mutants

PubMed Central

Schinko, Thorsten; Gallmetzer, Andreas; Amillis, Sotiris; Strauss, Joseph

2013-01-01

In fungi, transcriptional activation of genes involved in NO3- assimilation requires the presence of an inducer (nitrate or nitrite) and low intracellular concentrations of the pathway products ammonium or glutamine. In Aspergillus nidulans, the two transcription factors NirA and AreA act synergistically to mediate nitrate/nitrite induction and nitrogen metabolite derepression, respectively. In all studied fungi and in plants, mutants lacking nitrate reductase (NR) activity express nitrate-metabolizing enzymes constitutively without the addition of inducer molecules. Based on their work in A. nidulans, Cove and Pateman proposed an “autoregulation control” model for the synthesis of nitrate metabolizing enzymes in which the functional nitrate reductase molecule would act as co-repressor in the absence and as co-inducer in the presence of nitrate. However, NR mutants could simply show “pseudo-constitutivity” due to induction by nitrate which accumulates over time in NR-deficient strains. Here we examined this possibility using strains which lack flavohemoglobins (fhbs), and are thus unable to generate nitrate internally, in combination with nitrate transporter mutations (nrtA, nrtB) and a GFP-labeled NirA protein. Using different combinations of genotypes we demonstrate that nitrate transporters are functional also in NR null mutants and show that the constitutive phenotype of NR mutants is not due to nitrate accumulation from intracellular sources but depends on the activity of nitrate transporters. However, these transporters are not required for nitrate signaling because addition of external nitrate (10 mM) leads to standard induction of nitrate assimilatory genes in the nitrate transporter double mutants. We finally show that NR does not regulate NirA localization and activity, and thus the autoregulation model, in which NR would act as a co-repressor of NirA in the absence of nitrate, is unlikely to be correct. Results from this study instead suggest that transporter-mediated NO3- accumulation in NR deficient mutants, originating from traces of nitrate in the media, is responsible for the constitutive expression of NirA-regulated genes, and the associated phenotype is thus termed “pseudo-constitutive”. PMID:23454548

Serum nitrate/nitrite concentration correlates with gastric juice nitrate/nitrite: a possible marker for mutagenesis of the proximal stomach.

PubMed

Kishikawa, Hiroshi; Nishida, Jiro; Ichikawa, Hitoshi; Kaida, Shogo; Matsukubo, Takashi; Miura, Soichiro; Morishita, Tetsuo; Hibi, Toshifumi

2011-01-01

In the normal acid-secreting stomach, luminally generated nitric oxide, which contributes to carcinogenesis in the proximal stomach, is associated with the concentration of nitrate plus nitrite (nitrate/nitrite) in gastric juice. We investigated whether the serum nitrate/nitrite concentration is associated with that of gastric juice and whether it can be used as a serum marker. Serum and gastric juice nitrate/nitrite concentration, Helicobacter pylori antibody, and gastric pH were measured in 176 patients undergoing upper endoscopy. Multiple regression analysis revealed that serum nitrate/nitrite concentration was the best independent predictor of gastric juice nitrate/nitrite concentration. On single regression analysis, serum and gastric juice nitrate/nitrite concentration were significantly correlated, according to the following equation: gastric juice nitrate/nitrite concentration (μmol/l) = 3.93 - 0.54 × serum nitrate/nitrite concentration (μmol/l; correlation coefficient = 0.429, p < 0.001). In analyses confined to subjects with gastric pH less than 2.0, and in those with serum markers suggesting normal acid secretion (pepsinogen-I >30 ng/ml and negative H. pylori antibody), the serum nitrate/nitrite concentration was an independent predictor of the gastric juice nitrate/nitrite concentration (p < 0.001). Measuring the serum nitrate/nitrite concentration has potential in estimating the gastric juice nitrate/nitrite concentration. The serum nitrate/nitrite concentration could be useful as a marker for mutagenesis in the proximal stomach. Copyright © 2011 S. Karger AG, Basel.

Aminoethyl nitrate – the novel super nitrate?

PubMed Central

Bauersachs, Johann

2009-01-01

Long-term use of most organic nitrates is limited by development of tolerance, induction of oxidative stress and endothelial dysfunction. In this issue of the BJP, Schuhmacher et al. characterized a novel class of organic nitrates with amino moieties (aminoalkyl nitrates). Aminoethyl nitrate was identified as a novel organic mononitrate with high potency but devoid of induction of mitochondrial oxidative stress. Cross-tolerance to nitroglycerin or the endothelium-dependent agonist acetylcholine after in vivo treatment was not observed. Like all nitrates, aminoethyl nitrate induced vasorelaxation by activation of soluble guanylate cyclase. Thus, in contrast to the prevailing view, high potency in an organic nitrate is not necessarily accompanied by induction of oxidative stress or endothelial dysfunction. This work from Daiber's group is an important step forward in the understanding of nitrate bioactivation, tolerance phenomena and towards the development of better organic nitrates for clinical use. PMID:19732062

The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone.

PubMed

Wang, L; Butcher, A S; Stuart, M E; Gooddy, D C; Bloomfield, J P

2013-10-01

Nitrate pollution in groundwater, which is mainly from agricultural activities, remains an international problem. It threatens the environment, economics and human health. There is a rising trend in nitrate concentrations in many UK groundwater bodies. Research has shown it can take decades for leached nitrate from the soil to discharge into groundwater and surface water due to the 'store' of nitrate and its potentially long travel time in the unsaturated and saturated zones. However, this time lag is rarely considered in current water nitrate management and policy development. The aim of this study was to develop a catchment-scale integrated numerical method to investigate the nitrate lag time in the groundwater system, and the Eden Valley, UK, was selected as a case study area. The method involves three models, namely the nitrate time bomb-a process-based model to simulate the nitrate transport in the unsaturated zone (USZ), GISGroundwater--a GISGroundwater flow model, and N-FM--a model to simulate the nitrate transport in the saturated zone. This study answers the scientific questions of when the nitrate currently in the groundwater was loaded into the unsaturated zones and eventually reached the water table; is the rising groundwater nitrate concentration in the study area caused by historic nitrate load; what caused the uneven distribution of groundwater nitrate concentration in the study area; and whether the historic peak nitrate loading has reached the water table in the area. The groundwater nitrate in the area was mainly from the 1980s to 2000s, whilst the groundwater nitrate in most of the source protection zones leached into the system during 1940s-1970s; the large and spatially variable thickness of the USZ is one of the major reasons for unevenly distributed groundwater nitrate concentrations in the study area; the peak nitrate loading around 1983 has affected most of the study area. For areas around the Bowscar, Beacon Edge, Low Plains, Nord Vue, Dale Springs, Gamblesby, Bankwood Springs, and Cliburn, the peak nitrate loading will arrive at the water table in the next 34 years; statistical analysis shows that 8.7 % of the Penrith Sandstone and 7.3 % of the St Bees Sandstone have not been affected by peak nitrate. This research can improve the scientific understanding of nitrate processes in the groundwater system and support the effective management of groundwater nitrate pollution for the study area. With a limited number of parameters, the method and models developed in this study are readily transferable to other areas.

Light-Dark Changes in Cytosolic Nitrate Pools Depend on Nitrate Reductase Activity in Arabidopsis Leaf Cells1[w

PubMed Central

Cookson, Sarah J.; Williams, Lorraine E.; Miller, Anthony J.

2005-01-01

Several different cellular processes determine the size of the metabolically available nitrate pool in the cytoplasm. These processes include not only ion fluxes across the plasma membrane and tonoplast but also assimilation by the activity of nitrate reductase (NR). In roots, the maintenance of cytosolic nitrate activity during periods of nitrate starvation and resupply (M. van der Leij, S.J. Smith, A.J. Miller [1998] Planta 205: 64–72; R.-G. Zhen, H.-W. Koyro, R.A. Leigh, A.D. Tomos, A.J. Miller [1991] Planta 185: 356–361) suggests that this pool is regulated. Under nitrate-replete conditions vacuolar nitrate is a membrane-bound store that can release nitrate to the cytoplasm; after depletion of cytosolic nitrate, tonoplast transporters would serve to restore this pool. To study the role of assimilation, specifically the activity of NR in regulating the size of the cytosolic nitrate pool, we have compared wild-type and mutant plants. In leaf mesophyll cells, light-to-dark transitions increase cytosolic nitrate activity (1.5–2.8 mm), and these changes were reversed by dark-to-light transitions. Such changes were not observed in nia1nia2 NR-deficient plants indicating that this change in cytosolic nitrate activity was dependent on the presence of functional NR. Furthermore, in the dark, the steady-state cytosolic nitrate activities were not statistically different between the two types of plant, indicating that NR has little role in determining resting levels of nitrate. Epidermal cells of both wild type and NR mutants had cytosolic nitrate activities that were not significantly different from mesophyll cells in the dark and were unaltered by dark-to-light transitions. We propose that the NR-dependent changes in cytosolic nitrate provide a cellular mechanism for the diurnal changes in vacuolar nitrate storage, and the results are discussed in terms of the possible signaling role of cytosolic nitrate. PMID:15908593

Identifying source and formation altitudes of nitrates in drinking water from Réunion Island, France, using a multi-isotopic approach.

PubMed

Rogers, Karyne M; Nicolini, Eric; Gauthier, Virginie

2012-09-01

Nitrate concentrations, water isotopes (δ(2)H and δ(18)O(water)) and associated nitrate isotopes (δ(15)N(nitrate) and δ(18)O(nitrate)) from 10 drinking water wells, 5 fresh water springs and the discharge from 3 wastewater treatment stations in Réunion Island, located in the Indian Ocean, were analysed. We used a multi isotopic approach to investigate the extent of nitrate contamination, nitrate formation altitude and source of nitrates in Réunion Island's principal aquifer. Water from these study sites contained between 0.1 and 85.3 mg/L nitrate. δ(15)N(nitrate) values between +6 and +14‰ suggested the main sources of contamination were animal and/or human waste, rather than inorganic (synthetic) fertilisers, infiltrating through the subsurface into the saturated zone, due to rainfall leaching of the unsaturated zone at various altitudes of precipitation. Based on δ(15)N(nitrate) values alone, it was not possible to distinguish between animal and human activities responsible for the contamination of each specific catchment. However, using a multi isotope approach (δ(18)O(water) and δ(15)N(nitrate)), it was possible to relate the average altitude of rainfall infiltration (δ(18)O(water)) associated with the nitrate contamination (δ(18)O(nitrate)). This relationship between land use, rainfall recharge altitude and isotopic composition (δ(15)N(nitrate) and δ(18)O(water)) discriminated between the influences of human waste at lower (below 600 m elevation) or animal derived contamination (at elevations between 600 and 1300 m). By further comparing the theoretical altitude of nitrate formation calculated by the δ(18)O(nitrate), it was possible to determine that only 5 out of 15 fresh water wells and springs followed the conservative nitrate formation mechanism of 2/3δ(18)O(water)+1/3δ(18)O(air), to give nitrate formation altitudes which corresponded to land use activities. Copyright © 2012 Elsevier B.V. All rights reserved.

Family-based association study between monoamine oxidase A (MAOA) gene promoter VNTR polymorphism and Tourette's syndrome in Chinese Han population.

PubMed

Liu, Shiguo; Wang, Xueqin; Xu, Longqiang; Zheng, Lanlan; Ge, Yinlin; Ma, Xu

2015-02-01

To clarify the association of monoamine oxidase A- variable number of tandem repeat (MAOA-pVNTR) with susceptibility to Tourette's syndrome (TS) in Chinese Han population we discuss the genetic contribution of MAOA-VNTR in 141 TS patients including all their parents in Chinese Han population using transmission disequilibrium test (TDT) design. Our results revealed that no significant association was found in the MAOA gene promoter VNTR polymorphism and TS in Chinese Han population (TDT = 1.515, df = 1, p > 0.05). The negative result may be mainly due to the small sample size, but we don't deny the role of gene coding serotonergic or monoaminergic structures in the etiology of TS.

Incidence of gastroesophageal reflux disease in Uygur and Han Chinese adults in Urumqi

PubMed Central

Niu, Chun-Yan; Zhou, Yong-Li; Yan, Rong; Mu, Ni-La; Gao, Bao-Hua; Wu, Fang-Xiong; Luo, Jin-Yan

2012-01-01

AIM: To investigate the incidence of gastroesophageal reflux disease (GERD) and its related risk factors in Uygur and Han Chinese adult in Urumqi, China. METHODS: A population-based cross-sectional survey was undertaken in a total of 972 Uygur (684 male and 288 female) aged from 24 to 61 and 1023 Han Chinese (752 male and 271 female) aged from 23 to 63 years. All participants were recruited from the residents who visited hospital for health examination from November 2011 to May 2012. Each participant signed an informed consent and completed a GERD questionnaire (Gerd Q) and a lifestyle-food frequency questionnaire survey. Participants whose Gerd Q score was ≥ 8 and met one of the following requirements would be enrolled into this research: (1) being diagnosed with erosive esophagitis (EE) or Barrett’s esophagus (BE) by endoscopy; (2) negative manifestation under endoscopy (non-erosive reflux disease, NERD) with abnormal acid reflux revealed by 24-h esophageal pH monitoring; and (3) suffering from typical heartburn and regurgitation with positive result of proton pump inhibitor test. RESULTS: According to Gerd Q scoring criteria, 340 cases of Uygur and 286 cases of Han Chinese were defined as GERD. GERD incidence in Uygur was significantly higher than in Han Chinese (35% vs 28%, χ2 = 11.09, P < 0.005), Gerd Q score in Uygur was higher than in Han Chinese (7.85 ± 3.1 vs 7.15 ± 2.9, P < 0.005), and Gerd Q total score in Uygur male was higher than in female (8.15 ± 2.8 vs 6.85 ± 2.5, P < 0.005). According to normalized methods, 304 (31%) cases of Uygur were diagnosed with GERD, including 89 cases of EE, 185 cases of NERD and 30 cases of BE; 256 (25%) cases of Han Chinese were diagnosed with GERD, including 90 cases of EE, 140 cases of NERD and 26 cases of BE. GERD incidence in Uygur was significantly higher than in Han Chinese (31% vs 25%, χ2 = 9.34, P < 0.005) while the incidences were higher in males of both groups than in females (26% vs 5% in Uygur, χ2 = 35.95, P < 0.005, and 19.8% vs 5.2% in Han, χ2 = 5.48, P < 0.025). GERD incidence in Uygur male was higher than in Han Chinese male (26% vs 19.8%, χ2 = 16.51, P < 0.005), and incidence of NERD in Uygur was higher than in Han Chinese (χ2 = 10.06, P < 0.005). Occupation (r = 0.623), gender (r = 0.839), smoking (r = 0.322), strong tea (r = 0.658), alcohol drinking (r = 0.696), meat-based diet (mainly meat) (r = 0.676) and body mass index (BMI) (r = 0.567) were linearly correlated with GERD in Uygur (r = 0.833, P = 0.000); while gender (r = 0.957), age (r = 0.016), occupation (r = 0.482), strong tea (r = 1.124), alcohol drinking (r = 0.558), meat diet (r = 0.591) and BMI (r = 0.246) were linearly correlated with GERD in Han Chinese (r = 0.786, P = 0.01). There was no significant difference between Gerd Q scoring and three normalized methods for the diagnosis of GERD. CONCLUSION: GERD is highly prevalent in adult in Urumqi, especially in Uygur. Male, civil servant, smoking, strong tea, alcohol drinking, meat diet and BMI are risk factors correlated to GERD. PMID:23326142

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 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...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 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...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 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...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 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...

California GAMA Special Study: An isotopic and dissolved gas investigation of nitrate source and transport to a public supply well in California's Central Valley

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singleton, M J; Moran, J E; Esser, B K

2010-04-14

This study investigates nitrate contamination of a deep municipal drinking water production well in Ripon, CA to demonstrate the utility of natural groundwater tracers in constraining the sources and transport of nitrate to deep aquifers in the Central Valley. The goal of the study was to investigate the origin (source) of elevated nitrate and the potential for the deep aquifer to attenuate anthropogenic nitrate. The site is ideal for such an investigation. The production well is screened from 165-325 feet below ground surface and a number of nearby shallow and deep monitoring wells were available for sampling. Furthermore, potential sourcesmore » of nitrate contamination to the well had been identified, including a fertilizer supply plant located approximately 1000 feet to the east and local almond groves. A variety of natural isotopic and dissolved gas tracers including {sup 3}H-{sup 3}He groundwater age and the isotopic composition of nitrate are applied to identify nitrate sources and to characterize nitrate transport. An advanced method for sampling production wells is employed to help identify contaminant contributions from specific screen intervals. Nitrate transport: Groundwater nitrate at this field site is not being actively denitrified. Groundwater parameters indicate oxic conditions, the dissolved gas data shows no evidence for excess nitrogen as the result of denitrification, and nitrate-N and -O isotope compositions do not display patterns typical of denitrification. Contaminant nitrate source: The ambient nitrate concentration in shallow groundwater at the Ripon site ({approx}12 mg/L as nitrate) is typical of shallow groundwaters affected by recharge from agricultural and urban areas. Nitrate concentrations in Ripon City Well 12 (50-58 mg/L as nitrate) are significantly higher than these ambient concentrations, indicating an additional source of anthropogenic nitrate is affecting groundwater in the capture zone of this municipal drinking water well. This study provides two new pieces of evidence that the Ripon Farm Services Plant is the source of elevated nitrate in Ripon City Well 12. (1) Chemical mass balance calculations using nitrate concentration, nitrate isotopic composition, and initial tritium activity all indicate that that the source water for elevated nitrate to Ripon City Well 12 is a very small component of the water produced by City Well 12 and thus must have extremely high nitrate concentration. The high source water nitrate concentration ({approx}1500 mg/L as nitrate) required by these mass balance calculations precludes common sources of nitrate such as irrigated agriculture, dairy wastewater, and septic discharge. Shallow groundwater under the Ripon Farm Services RFS plant does contain extremely high concentrations of nitrate (>1700 mg/L as nitrate). (2) Nitrogen and oxygen isotope compositions of nitrate indicate that the additional anthropogenic nitrate source to Ripon City Well 12 is significantly enriched in {delta}{sup 18}O-NO{sub 3}, an isotopic signature consistent with synthetic nitrate fertilizer, and not with human or animal wastewater discharge (i.e. dairy operations, septic system discharge, or municipal wastewater discharge), or with organic fertilizer. Monitoring wells on and near the RFS plant also have high {delta}{sup 18}O-NO{sub 3}, and the plant has handled and stored synthetic nitrate fertilizer that will have this isotopic signature. The results described here highlight the complexity of attributing nitrate found in long screened, high capacity wells to specific sources. In this case, the presence of a very high concentration source near the well site combined with sampling using multiple isotopic tracer techniques and specialized depth-specific techniques allowed fingerprinting of the source in the mixed-age samples drawn from the production well.« less

[A cross-sectional survey on behavior problems among eco-migrant children of Hui and Han in Ningxia, China].

PubMed

Yan, Guoli; Fang, Jianqun; Zhang, Zhaoxia; Feng, Liping; Wu, Jinrong; Ma, Fuli; Chen, Shiqi; Zhao, Ranran; Wang, Yingli; Wang, Zhizhong

2014-02-01

To investigate the detection rate and correlates of behavioral problems among eco-migrant children in Hui and Han ethnicities. Using multistage randomized sampling method, 2 653 eco-migrant teenagers, 3 174 indigenous and 2 334 homeland peers were selected. Their parents were asked to finish the Achenbach's Child Behavior Checklist (CBCL) and a self-developed correlates questionnaire. 765 eco-migrant children with behavioral problems were detected, with detection rate as 28.8%, higher than that of homeland group (24.2%) and native group (19.3%) (χ(2) = 73.547, P < 0.012 5). Ecological migration mainly influenced factors as bad contacts, depression, obsessive-compulsive, discipline, attack for boys aged 6-11, bad contacts for boys aged 12-16 and extraversion behavioral problems for girls aged 12-16, in Hui. These factors both associated to eco-migrant children's behavioral problems in Hui and Han:cesarean section (OR = 1.863, 95% CI:1.144-3.035, for Han) and (OR = 2.979, 95% CI:2.067-4.293, for Hui), physical defects (OR = 1.730, 95%CI:1.087-2.751, for Han) and (OR = 2.552, 95%CI:1.649-3.950, for Hui), arable as a main income way(OR = 1.272, 95%CI:1.066-1.518, for Han) and (OR = 1.212, 95%CI: 1.033-1.422, for Hui), parents' education level above middle school (OR = 0.709, 95% CI: 0.539-0.932, for Han) and (OR = 0.698, 95%CI: 0.542-0.898, for Hui), parents' frequently in good mood (OR = 0.710, 95%CI:0.613-0.821, for Han) and (OR = 0.826, 95%CI:0.718-0.949, for Hui). However, major diseases in the process of growth (OR = 1.794, 95% CI:1.163-2.767), and parents with chronic illness or disability (OR = 1.463, 95% CI:1.061-2.016) only associated with that in Han;single-parent or remarried families(OR = 1.583, 95% CI:1.078-2.325), parents often drinking (OR = 1.557, 95%CI:1.019- 2.379), the time of parents' work longer than half a year (OR = 1.494, 95% CI:1.197-1.864), parents' more content to life now(OR = 0.813, 95% CI:0.700-0.945), and children in older age (OR = 0.939, 95%CI:0.889-0.991) only related to that in Hui. The eco-migrant children showed a low state in mental health, especially among Hui peers, and the correlated factors were different in Han and Hui, which was supposed to get great importance when taking effective intervention.

Disproportionation of hydroxylamine by water-soluble iron(III) porphyrinate compounds.

PubMed

Bari, Sara E; Amorebieta, Valentín T; Gutiérrez, María M; Olabe, José A; Doctorovich, Fabio

2010-01-01

The reactions of hydroxylamine (HA) with several water-soluble iron(III) porphyrinate compounds, namely iron(III) meso-tetrakis-(N-ethylpyridinium-2yl)-porphyrinate ([Fe(III)(TEPyP)](5+)), iron(III) meso-tetrakis-(4-sulphonatophenyl)-porphyrinate ([Fe(III)(TPPS)](3-)), and microperoxidase 11 ([Fe(III)(MP11)]) were studied for different [Fe(III)(Porph)]/[HA] ratios, under anaerobic conditions at neutral pH. Efficient catalytic processes leading to the disproportionation of HA by these iron(III) porphyrinates were evidenced for the first time. As a common feature, only N(2) and N(2)O were found as gaseous, nitrogen-containing oxidation products, while NH(3) was the unique reduced species detected. Different N(2)/N(2)O ratios obtained with these three porphyrinates strongly suggest distinctive mechanistic scenarios: while [Fe(III)(TEPyP)](5+) and [Fe(III)(MP11)] formed unknown steady-state porphyrinic intermediates in the presence of HA, [Fe(III)(TPPS)](3-) led to the well characterized soluble intermediate, [Fe(II)(TPPS)NO](4-). Free-radical formation was only evidenced for [Fe(III)(TEPyP)](5+), as a consequence of a metal centered reduction. We discuss the catalytic pathways of HA disproportionation on the basis of the distribution of gaseous products, free radicals formation, the nature of porphyrinic intermediates, the Fe(II)/Fe(III) redox potential, the coordinating capabilities of each complex, and the kinetic analysis. The absence of NO(2)(-) revealed either that no HAO-like activity was operative under our reaction conditions, or that NO(2)(-), if formed, was consumed in the reaction milieu.

Characterization of Anammox Hydrazine Dehydrogenase, a Key N2-producing Enzyme in the Global Nitrogen Cycle*

PubMed Central

Maalcke, Wouter J.; Reimann, Joachim; de Vries, Simon; Butt, Julea N.; Dietl, Andreas; Kip, Nardy; Mersdorf, Ulrike; Barends, Thomas R. M.; Jetten, Mike S. M.; Keltjens, Jan T.; Kartal, Boran

2016-01-01

Anaerobic ammonium-oxidizing (anammox) bacteria derive their energy for growth from the oxidation of ammonium with nitrite as the electron acceptor. N2, the end product of this metabolism, is produced from the oxidation of the intermediate, hydrazine (N2H4). Previously, we identified N2-producing hydrazine dehydrogenase (KsHDH) from the anammox organism Kuenenia stuttgartiensis as the gene product of kustc0694 and determined some of its catalytic properties. In the genome of K. stuttgartiensis, kustc0694 is one of 10 paralogs related to octaheme hydroxylamine (NH2OH) oxidoreductase (HAO). Here, we characterized KsHDH as a covalently cross-linked homotrimeric octaheme protein as found for HAO and HAO-related hydroxylamine-oxidizing enzyme kustc1061 from K. stuttgartiensis. Interestingly, the HDH trimers formed octamers in solution, each octamer harboring an amazing 192 c-type heme moieties. Whereas HAO and kustc1061 are capable of hydrazine oxidation as well, KsHDH was highly specific for this activity. To understand this specificity, we performed detailed amino acid sequence analyses and investigated the catalytic and spectroscopic (electronic absorbance, EPR) properties of KsHDH in comparison with the well defined HAO and kustc1061. We conclude that HDH specificity is most likely derived from structural changes around the catalytic heme 4 (P460) and of the electron-wiring circuit comprising seven His/His-ligated c-type hemes in each subunit. These nuances make HDH a globally prominent N2-producing enzyme, next to nitrous oxide (N2O) reductase from denitrifying microorganisms. PMID:27317665

Enhancement of bromate formation by pH depression during ozonation of bromide-containing water in the presence of hydroxylamine.

PubMed

Yang, Jingxin; Li, Ji; Dong, Wenyi; Ma, Jun; Yang, Yi; Li, Jiayin; Yang, Zhichao; Zhang, Xiaolei; Gu, Jia; Xie, Wanying; Cang, Yan

2017-02-01

This work investigated the fate of bromate formation during ozonation in the presence of hydroxylamine (HA). Results indicated that pH depression, as a commonly feasible control strategy for bromate formation during ozonation, unexpectedly enhanced the bromate formation during ozonation in the presence of HA. A dramatically high level of bromate was observed at acidic pH in the ozone/HA process. The scavenging experiments demonstrated the essential role of OH produced in the reaction of ozone with HA in bromate formation. In the process, OH mainly oxidizes bromide to Br, which is further oxidized by ozone and eventually converts to bromate. Further investigations suggested that the unexpected enhancement on bromate formation by pH depression can be mainly ascribed to the pH-dependent ozone decay, OH exposures and formation rate of Br. As pH decreased from 7 to 5, the reduced OH scavenging capacity of HA led to higher OH exposures, which contributed to the enhancement of bromate formation. As pH decreased from 5 to 3, the enhanced formation rate of Br largely augmented the formation of bromate. In addition, the ozone decay slowed down by pH depression provided more available ozone for the oxidation of the formed Br to bromate. The enhanced effect of pH depression on bromate formation was still observed in the real water samples in the ozone/HA process. Accordingly, pH depression might be avoided to control the bromate formation during ozonation in the presence of HA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methyl-Hydroxylamine as an Efficacious Antibacterial Agent That Targets the Ribonucleotide Reductase Enzyme

PubMed Central

Julián, Esther; Baelo, Aida; Gavaldà, Joan; Torrents, Eduard

2015-01-01

The emergence of multidrug-resistant bacteria has encouraged vigorous efforts to develop antimicrobial agents with new mechanisms of action. Ribonucleotide reductase (RNR) is a key enzyme in DNA replication that acts by converting ribonucleotides into the corresponding deoxyribonucleotides, which are the building blocks of DNA replication and repair. RNR has been extensively studied as an ideal target for DNA inhibition, and several drugs that are already available on the market are used for anticancer and antiviral activity. However, the high toxicity of these current drugs to eukaryotic cells does not permit their use as antibacterial agents. Here, we present a radical scavenger compound that inhibited bacterial RNR, and the compound's activity as an antibacterial agent together with its toxicity in eukaryotic cells were evaluated. First, the efficacy of N-methyl-hydroxylamine (M-HA) in inhibiting the growth of different Gram-positive and Gram-negative bacteria was demonstrated, and no effect on eukaryotic cells was observed. M-HA showed remarkable efficacy against Mycobacterium bovis BCG and Pseudomonas aeruginosa. Thus, given the M-HA activity against these two bacteria, our results showed that M-HA has intracellular antimycobacterial activity against BCG-infected macrophages, and it is efficacious in partially disassembling and inhibiting the further formation of P. aeruginosa biofilms. Furthermore, M-HA and ciprofloxacin showed a synergistic effect that caused a massive reduction in a P. aeruginosa biofilm. Overall, our results suggest the vast potential of M-HA as an antibacterial agent, which acts by specifically targeting a bacterial RNR enzyme. PMID:25782003

Heme-bound nitroxyl, hydroxylamine, and ammonia ligands as intermediates in the reaction cycle of cytochrome c nitrite reductase: a theoretical study.

PubMed

Bykov, Dmytro; Plog, Matthias; Neese, Frank

2014-01-01

In this article, we consider, in detail, the second half-cycle of the six-electron nitrite reduction mechanism catalyzed by cytochrome c nitrite reductase. In total, three electrons and four protons must be provided to reach the final product, ammonia, starting from the HNO intermediate. According to our results, the first event in this half-cycle is the reduction of the HNO intermediate, which is accomplished by two PCET reactions. Two isomeric radical intermediates, HNOH(•) and H2NO(•), are formed. Both intermediates are readily transformed into hydroxylamine, most likely through intramolecular proton transfer from either Arg114 or His277. An extra proton must enter the active site of the enzyme to initiate heterolytic cleavage of the N-O bond. As a result of N-O bond cleavage, the H2N(+) intermediate is formed. The latter readily picks up an electron, forming H2N(+•), which in turn reacts with Tyr218. Interestingly, evidence for Tyr218 activity was provided by the mutational studies of Lukat (Biochemistry 47:2080, 2008), but this has never been observed in the initial stages of the overall reduction process. According to our results, an intramolecular reaction with Tyr218 in the final step of the nitrite reduction process leads directly to the final product, ammonia. Dissociation of the final product proceeds concomitantly with a change in spin state, which was also observed in the resonance Raman investigations of Martins et al. (J Phys Chem B 114:5563, 2010).

N-hydroxylamine is not an intermediate in the conversion of L-arginine to an activator of soluble guanylate cyclase in neuroblastoma N1E-115 cells.

PubMed Central

Pou, S; Pou, W S; Rosen, G M; el-Fakahany, E E

1991-01-01

This study evaluates the role of N-hydroxylamine (NH2OH) in activating soluble guanylate cyclase in the mouse neuroblastoma clone N1E-115. It has been proposed that NH2OH is a putative intermediate in the biochemical pathway for the generation of nitric oxide (NO)/endothelium-derived relaxing factor (EDRF) from L-arginine. NH2OH caused a time- and concentration-dependent increase in cyclic GMP formation in intact cells. This response was not dependent on Ca2+. In cytosol preparations the activation of guanylate cyclase by L-arginine was dose-dependent and required Ca2+ and NADPH. In contrast, NH2OH itself did not activate cytosolic guanylate cyclase but it inhibited the basal activity of this enzyme in a concentration-dependent manner. The formation of cyclic GMP in the cytosolic fractions in response to NH2OH required the addition of catalase and H2O2. On the other hand, catalase and/or H2O2 lead to a decrease in L-arginine-induced cyclic GMP formation. Furthermore, NH2OH inhibited L-arginine- and sodium nitroprusside-induced cyclic GMP formation in the cytosol. The inhibition of L-arginine-induced cyclic GMP formation in the cytosol by NH2OH was not reversed by the addition of superoxide dismutase. These data strongly suggest that NH2OH is not a putative intermediate in the metabolism of L-arginine to an activator of guanylate cyclase. PMID:1671745

Characteristics of N2O production and hydroxylamine variation in short-cut nitrification SBR process.

PubMed

Hu, Bo; Ye, Junhong; Zhao, Jianqiang; Ding, Xiaoqian; Yang, Liwei; Tian, Xiaolei

2018-01-01

In order to study the characteristics of nitrous oxide (N 2 O) production and hydroxylamine (NH 2 OH) variation under oxic conditions, concentrations of NH 2 OH and N 2 O were simultaneously monitored in a short-cut nitrification sequencing batch reactor (SBR) operated with different influent ammonia concentrations. In the short-cut nitrification process, N 2 O production was increased with the increasing of ammonia concentration in influent. The maximum concentrations of dissolved N 2 O-N in the reactor were 0.11 mg/L and 0.52 mg/L when ammonia concentrations in the influent were 50 mg/L and 70 mg/L respectively. Under the low and medium ammonia load phases, the concentrations of NH 2 OH-N in the reactor were remained at a low level which fluctuated around 0.06 mg/L in a small range, and did not change with the variation of influent NH 4 + -N concentration. Based on the determination results, the half-saturation of NH 2 OH in the biochemical conversion process of NH 2 OH to NO 2 - -N was very small, and the value of 0.05 mg NH 2 OH-N/L proposed in the published literature was accurate. NH 2 OH is an important intermediate in the nitrification process, and the direct determination of NH 2 OH in the nitrification process was beneficial for revealing the kinetic process of NH 2 OH production and consumption as well as the effects of NH 2 OH on N 2 O production in the nitrification process.

Photoproduction of One-Electron Reducing Intermediates by Chromophoric Dissolved Organic Matter (CDOM): Relation to O2- and H2O2 Photoproduction and CDOM Photooxidation.

PubMed

Zhang, Yi; Blough, Neil V

2016-10-06

A molecular probe, 3-amino-2,2,5,5,-tetramethy-1-pyrrolydinyloxy (3ap), was employed to determine the formation rates of one-electron reducing intermediates generated photochemically from both untreated and borohydride-reduced Suwanee River fulvic and humic acids (SRFA and SRHA, respectively). This stable nitroxyl radical reacts rapidly with reducing radicals and other one-electron reductants to produce a relatively stable product, the hydroxylamine, which can be derivatized with fluorescamine, separated by HPLC and quantified fluorimetrically. We provide evidence that O 2 and 3ap compete for the same pool(s) of photoproduced reducing intermediates, and that under appropriate experimental conditions, the initial rate of hydroxylamine formation (R H ) can provide an estimate of the initial rate of superoxide (O 2 - ) formation. However, comparison of the initial rates of H 2 O 2 formation (R H2O2 ) to that of R H show far larger ratios of R H /R H2O2 (∼6-13) than be accounted for by simple O 2 - dismutation (R H /R H2O2 = 2), implying a significant oxidative sink of O 2 - (∼67-85%). Because of their high reactivity with O 2 - and their likely importance in the photochemistry of CDOM, we suggest that coproduced phenoxy radicals could represent a viable oxidative sink. Because O 2 - /phenoxy radical reactions can lead to more highly oxidized products, O 2 - could be playing a far more significant role in the photooxidation of CDOM than has been previously recognized.

Development of a voltammetric assay, using screen-printed electrodes, for clonazepam and its application to beverage and serum samples.

PubMed

Honeychurch, Kevin C; Brooks, Joshua; Hart, John P

2016-01-15

This paper describes the development of an electrochemical assay based on screen-printed carbon sensors for the determination of clonazepam in serum and in wine. The cyclic voltammetric behaviour of the drug was investigated and the effects of pH and scan rate on the peak current and peak potential determined. Two reduction peaks were recorded on the initial negative going scan, which were considered to result from the 2e(-), 2 H(+) reduction of the 4,5-azomethine and from the 4e(-), 4 H(+) reduction of the 7-NO2 to a hydroxylamine. On the return positive going scan an oxidation peak was seen, which was considered to result from the 2e(-), 2 H(+) oxidation (O1) of the hydroxylamine to the corresponding nitroso species. At pH 11 the solution of clonazepam was found to turn from clear to yellow in colour and the voltammetric signal of the O1 oxidation process was found to be adsorptive in nature, this was exploited in the development of an adsorptive stripping voltammetric assay. Experimental conditions were then optimised for the differential pulse adsorptive voltammetric measurement of clonazepam in wine and serum samples. It was shown that these analyses could be performed on only 100µL of sample which was deposited on the sensor surface. Mean recoveries of 79.53% (%CV=9.88%) and 88.22% (%CV=14.1%) were calculated for wine fortified with 3.16µg/mL and serum fortified with 12.6µg/mL. Copyright © 2015 Elsevier B.V. All rights reserved.

Testing Mechanisms of Mercury Retention in GFD Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beatty, W.L.; Schroeder, K.T.; Kairies, C.L.

2007-07-01

The natural mode of retention of Hg in FGD products is a key issue in the utilization of coal byproducts as environmentally acceptable resources. This is being investigated with a sequential extraction scheme that subjects FGD material to a series of phase-targeted reagents. Mineral phases with the greatest affinity for Hg and the form in which Hg is naturally immobilized can be discovered by observing the amount of Hg mobilized by each successive extracting solution. The extraction procedure consists of a prolonged water rinse in a continuously stirred tank extractor to dissolve CaSO4 followed by a series of batch extractions.more » These extraction include: a water rinse of the resulting residue to remove any remaining water soluble and loosely sorbed ions, 0.11M acetic acid to target carbonate minerals and exchangeable ions, 0.1 M hydroxylamine hydrochloride to dissolve manganese oxides and hydroxides, 0.25 M hydroxylamine hydrochloride in 0.25 M HCl to dissolve iron oxides and hydroxides, and hydrogen peroxide and 0.1 M ammonium acetate to oxidize organic matter and dissolve sulfide minerals. Analysis of the supernatant after each extraction step includes ICP-OES or ICP-MS for major and trace elemental composition and CVAF for mercury. Initial results indicate that Hg is associated with two distinct fractions of FGD materials. Although most of the solubilized Hg is extracted by the iron oxide and hydroxide dissolution reagent, ICP analysis suggests an association with clay minerals present in this fraction. The organic matter and sulfide minerals fraction typically yields lower but still significant amounts of Hg.« less

Azimuth Check: An Analysis of Military Transformation in the Republic of Korea-is it Sufficient

DTIC Science & Technology

2009-12-01

States (US) forces organized, trained, and equipped to deal with a complex and ambiguous collapse of the Democratic People’s Republic of 1 Yong -sup...Han, “Analyzing South Korea’s Defense Reform 2020,” The Korean Journal of Defense Analysis 18, no. 1 (Spring 2006): 111. 2 Yong -sup Han, 115. Han...2006, US Secretary of Defense Donald Rumsfeld and ROK Defense Minister Yoon Kwang- Ung jointly announced transition of wartime operational control

Food sources of nitrates and nitrites: the physiologic context for potential health benefits.

PubMed

Hord, Norman G; Tang, Yaoping; Bryan, Nathan S

2009-07-01

The presence of nitrates and nitrites in food is associated with an increased risk of gastrointestinal cancer and, in infants, methemoglobinemia. Despite the physiologic roles for nitrate and nitrite in vascular and immune function, consideration of food sources of nitrates and nitrites as healthful dietary components has received little attention. Approximately 80% of dietary nitrates are derived from vegetable consumption; sources of nitrites include vegetables, fruit, and processed meats. Nitrites are produced endogenously through the oxidation of nitric oxide and through a reduction of nitrate by commensal bacteria in the mouth and gastrointestinal tract. As such, the dietary provision of nitrates and nitrites from vegetables and fruit may contribute to the blood pressure-lowering effects of the Dietary Approaches to Stop Hypertension (DASH) diet. We quantified nitrate and nitrite concentrations by HPLC in a convenience sample of foods. Incorporating these values into 2 hypothetical dietary patterns that emphasize high-nitrate or low-nitrate vegetable and fruit choices based on the DASH diet, we found that nitrate concentrations in these 2 patterns vary from 174 to 1222 mg. The hypothetical high-nitrate DASH diet pattern exceeds the World Health Organization's Acceptable Daily Intake for nitrate by 550% for a 60-kg adult. These data call into question the rationale for recommendations to limit nitrate and nitrite consumption from plant foods; a comprehensive reevaluation of the health effects of food sources of nitrates and nitrites is appropriate. The strength of the evidence linking the consumption of nitrate- and nitrite-containing plant foods to beneficial health effects supports the consideration of these compounds as nutrients.

Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

ERIC Educational Resources Information Center

Bretherick, Leslie

1989-01-01

Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... Solids), Class 5 (Oxidizers and Organic Peroxides), and Division 1.5 Materials § 176.415 Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as...

Toxicity of drinking water disinfection byproducts: cell cycle alterations induced by the monohaloacetonitriles.

PubMed

Komaki, Yukako; Mariñas, Benito J; Plewa, Michael J

2014-10-07

Haloacetonitriles (HANs) are a chemical class of drinking water disinfection byproducts (DBPs) that form from reactions between disinfectants and nitrogen-containing precursors, the latter more prevalent in water sources impacted by algae bloom and municipal wastewater effluent discharge. HANs, previously demonstrated to be genotoxic, were investigated for their effects on the mammalian cell cycle. Treating Chinese hamster ovary (CHO) cells with monoHANs followed by the release from the chemical treatment resulted in the accumulation of abnormally high DNA content in cells over time (hyperploid). The potency for the cell cycle alteration followed the order: iodoacetonitrile (IAN) > bromoacetonitrile (BAN) ≫ chloroacetonitrile (CAN). Exposure to 6 μM IAN, 12 μM BAN and 900 μM CAN after 26 h post-treatment incubation resulted in DNA repair; however, subsequent cell cycle alteration effects were observed. Cell proliferation of HAN-treated cells was suppressed for as long as 43 to 52 h. Enlarged cell size was observed after 52 h post-treatment incubation without the induction of cytotoxicity. The HAN-mediated cell cycle alteration was mitosis- and proliferation-dependent, which suggests that HAN treatment induced mitosis override, and that HAN-treated cells proceeded into S phase and directly into the next cell cycle. Cells with multiples genomes would result in aneuploidy (state of abnormal chromosome number and DNA content) at the next mitosis since extra centrosomes could compromise the assembly of bipolar spindles. There is accumulating evidence of a transient tetraploid state proceeding to aneuploidy in cancer progression. Biological self-defense systems to ensure genomic stability and to eliminate tetraploid cells exist in eukaryotic cells. A key tumor suppressor gene, p53, is oftentimes mutated in various types of human cancer. It is possible that HAN disruption of the normal cell cycle and the generation of aberrant cells with an abnormal number of chromosomes may contribute to cancer induction and perhaps be involved in the induction of adverse pregnancy outcomes associated with long-term consumption of disinfected water. Here we present the first observation of the induction of hyperploidy by a class of DBPs.

[Polymorphism analysis of 20 autosomal short-tandem repeat loci in southern Chinese Han population].

PubMed

Chen, Ling; Lu, Hui-Jie; DU, Wei-An; Qiu, Ping-Ming; Liu, Chao

2016-02-20

To evaluate the value of PowerPlex ® 21 System (Promega) and study the genetic polymorphism of its 20 short-tandem repeat (STR) loci in southern Chinese Han population. We conducted genotyping experiments using PowerPlex ® 21 System on 20 autosomal STR loci (D3S1358, D1S1656, D6S1043, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433 and FGA) in 2367 unrelated Chinese Han individuals living in South China. The allele frequencies and parameters commonly used in forensic science were statistically analyzed in these individuals and compared with the reported data of other populations. The PowerPlex ® 21 System had a power of discrimination (PD) ranging from 0.7839 to 0.9852 and a power of exclusion (PE) ranging from 0.2974 to 0.8099 for the 20 loci. No significant deviation from Hardy-Weinberg expectations was found for all the loci except for D5S818. This southern Chinese Han population had significant differences in the allele frequencies from 8 ethnic groups reported in China, and showed significant differences at 8 to 20 STR foci from 5 foreign populations. The allele frequency at the locus D1S1656 in this southern Chinese Han population differed significantly from those in the 5 foreign populations and from 3 reported Han populations in Beijing, Zhejiang Province and Fujian Province of China. The neighbor-joining phylogenetictree showed clustering of all the Asian populations in one branch, while the northern Italian and Argentina populations clustered in a separate branch. This southern Chinese Han population had the nearest affinity with the Yi ethnic population in Yunnan Province of China. The 20 STR loci are highly polymorphic in this southern Chinese Han population, suggesting the value of this set of STR loci in forensic personal identification, paternity testing and anthropological study.

Ventilation and hypoxic ventilatory responsiveness in Chinese-Tibetan residents at 3,658 m.

PubMed

Curran, L S; Zhuang, J; Sun, S F; Moore, L G

1997-12-01

When breathing ambient air at rest at 3,658 m altitude, Tibetan lifelong residents of 3,658 m ventilate as much as newcomers acclimatized to high altitude; they also ventilate more and have greater hypoxic ventilatory responses (HVRs) than do Han ("Chinese") long-term residents at 3,658 m. This suggests that Tibetan ancestry is advantageous in protecting resting ventilation levels during years of hypoxic exposure and is of interest in light of the permissive role of hypoventilation in the development of chronic mountain sickness, which is nearly absent among Tibetans. The existence of individuals with mixed Tibetan-Chinese ancestry (Han-Tibetans) residing at 3,658 m affords an opportunity to test this hypothesis. Eighteen men born in Lhasa, Tibet, China (3,658 m) to Tibetan mothers and Han fathers were compared with 27 Tibetan men and 30 Han men residing at 3,658 m who were previously studied. We used the same study procedures (minute ventilation was measured with a dry-gas flowmeter during room air breathing and hyperoxia and with a 13-liter spirometer-rebreathing system during the hypoxic and hypercapnic tests). During room air breathing at 3,658 m (inspired O2 pressure = 93 Torr), Han-Tibetans resembled Tibetans in ventilation (12.1 +/- 0.6 vs. 11.5+/- 0.5 l/min BTPS, respectively) but had HVR that were blunted (63 +/- 16 vs. 121 +/- 13, respectively, for HVR shape parameter A) and declined with increasing duration of high-altitude residence. During administered hyperoxia (inspired O2 pressure = 310 Torr) at 3,658 m, the paradoxical hyperventilation previously seen in Tibetan but not Han residents at 3,658 m (11.8 +/- 0.5 vs. 10.1 +/- 0.5 l/min BTPS) was absent in these Han-Tibetans (9.8 +/- 0.6 l/min BTPS). Thus, although longer duration of high-altitude residence appears to progressively blunt HVR among Han-Tibetans born and residing at 3, 658 m, their Tibetan ancestry appears protective in their maintenance of high resting ventilation levels despite diminished chemosensitivity.

Mammalian Nitrate Biosynthesis: Incorporation of 15NH3 into Nitrate is Enhanced by Endotoxin Treatment

NASA Astrophysics Data System (ADS)

Wagner, David A.; Young, Vernon R.; Tannenbaum, Steven R.

1983-07-01

Incorporation of an oral dose of [15N]ammonium acetate into urinary [15N]nitrate has been demonstrated in the rat. Investigation of the regulation of nitrate synthesis has shown that Escherichia coli lipopolysaccharide potently stimulates urinary nitrate excretion (9-fold increase). It was further shown that the enhanced rate of nitrate excretion by lipopolysaccharide was due not to a reduction in nitrate metabolic loss but rather to an increased rate of synthesis. This conclusion was based on finding a proportionally increased incorporation of [15N]ammonium into nitrate nitrogen with lipopolysaccharide treatment. Nitrate biosynthesis was also increased by intraperitoneal injection of carrageenan and subcutaneous injection of turpentine. It is proposed that the pathway of nitrate biosynthesis may be the result of oxidation of reduced nitrogen compounds by oxygen radicals generated by an activated reticuloendothelial system.

The Arabidopsis NRG2 Protein Mediates Nitrate Signaling and Interacts with and Regulates Key Nitrate Regulators[OPEN

PubMed Central

Zhao, Lufei; Zhang, Chengfei; Li, Zehui; Lei, Zhao; Liu, Fei; Guan, Peizhu; Crawford, Nigel M.

2016-01-01

We show that NITRATE REGULATORY GENE2 (NRG2), which we identified using forward genetics, mediates nitrate signaling in Arabidopsis thaliana. A mutation in NRG2 disrupted the induction of nitrate-responsive genes after nitrate treatment by an ammonium-independent mechanism. The nitrate content in roots was lower in the mutants than in the wild type, which may have resulted from reduced expression of NRT1.1 (also called NPF6.3, encoding a nitrate transporter/receptor) and upregulation of NRT1.8 (also called NPF7.2, encoding a xylem nitrate transporter). Genetic and molecular data suggest that NRG2 functions upstream of NRT1.1 in nitrate signaling. Furthermore, NRG2 directly interacts with the nitrate regulator NLP7 in the nucleus, but nuclear retention of NLP7 in response to nitrate is not dependent on NRG2. Transcriptomic analysis revealed that genes involved in four nitrogen-related clusters including nitrate transport and response to nitrate were differentially expressed in the nrg2 mutants. A nitrogen compound transport cluster containing some members of the NRT/PTR family was regulated by both NRG2 and NRT1.1, while no nitrogen-related clusters showed regulation by both NRG2 and NLP7. Thus, NRG2 plays a key role in nitrate regulation in part through modulating NRT1.1 expression and may function with NLP7 via their physical interaction. PMID:26744214

Disruption of the rice nitrate transporter OsNPF2.2 hinders root-to-shoot nitrate transport and vascular development

PubMed Central

Li, Yuge; Ouyang, Jie; Wang, Ya-Yun; Hu, Rui; Xia, Kuaifei; Duan, Jun; Wang, Yaqin; Tsay, Yi-Fang; Zhang, Mingyong

2015-01-01

Plants have evolved to express some members of the nitrate transporter 1/peptide transporter family (NPF) to uptake and transport nitrate. However, little is known of the physiological and functional roles of this family in rice (Oryza sativa L.). Here, we characterized the vascular specific transporter OsNPF2.2. Functional analysis using cDNA-injected Xenopus laevis oocytes revealed that OsNPF2.2 is a low-affinity, pH-dependent nitrate transporter. Use of a green fluorescent protein tagged OsNPF2.2 showed that the transporter is located in the plasma membrane in the rice protoplast. Expression analysis showed that OsNPF2.2 is nitrate inducible and is mainly expressed in parenchyma cells around the xylem. Disruption of OsNPF2.2 increased nitrate concentration in the shoot xylem exudate when nitrate was supplied after a deprivation period; this result suggests that OsNPF2.2 may participate in unloading nitrate from the xylem. Under steady-state nitrate supply, the osnpf2.2 mutants maintained high levels of nitrate in the roots and low shoot:root nitrate ratios; this observation suggests that OsNPF2.2 is involved in root-to-shoot nitrate transport. Mutation of OsNPF2.2 also caused abnormal vasculature and retarded plant growth and development. Our findings demonstrate that OsNPF2.2 can unload nitrate from the xylem to affect the root-to-shoot nitrate transport and plant development. PMID:25923512

Profound differences between humans and rodents in the ability to concentrate salivary nitrate: Implications for translational research.

PubMed

Montenegro, Marcelo F; Sundqvist, Michaela L; Nihlén, Carina; Hezel, Michael; Carlström, Mattias; Weitzberg, Eddie; Lundberg, Jon O

2016-12-01

In humans dietary circulating nitrate accumulates rapidly in saliva through active transport in the salivary glands. By this mechanism resulting salivary nitrate concentrations are 10-20 times higher than in plasma. In the oral cavity nitrate is reduced by commensal bacteria to nitrite, which is subsequently swallowed and further metabolized to nitric oxide (NO) and other bioactive nitrogen oxides in blood and tissues. This entero-salivary circulation of nitrate is central in the various NO-like effects observed after ingestion of inorganic nitrate. The very same system has also been the focus of toxicologists studying potential carcinogenic effects of nitrite-dependent nitrosamine formation. Whether active transport of nitrate and accumulation in saliva occurs also in rodents is not entirely clear. Here we measured salivary and plasma levels of nitrate and nitrite in humans, rats and mice after administration of a standardized dose of nitrate. After oral (humans) or intraperitoneal (rodents) sodium nitrate administration (0.1mmol/kg), plasma nitrate levels increased markedly reaching ~300µM in all three species. In humans ingestion of nitrate was followed by a rapid increase in salivary nitrate to >6000µM, ie 20 times higher than those found in plasma. In contrast, in rats and mice salivary nitrate concentrations never exceeded the levels in plasma. Nitrite levels in saliva and plasma followed a similar pattern, ie marked increases in humans but modest elevations in rodents. In mice there was also no accumulation of nitrate in the salivary glands as measured directly in whole glands obtained after acute administration of nitrate. This study suggests that in contrast to humans, rats and mice do not actively concentrate circulating nitrate in saliva. These apparent species differences should be taken into consideration when studying the nitrate-nitrite-nitric oxide pathway in rodents, when calculating doses, exploring physiological, therapeutic and toxicological effects and comparing with human data. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

New insights into bioactivation of organic nitrates, nitrate tolerance and cross-tolerance.

PubMed

Daiber, A; Wenzel, P; Oelze, M; Münzel, T

2008-01-01

Organic nitrates still represent a group of very effective anti-ischemic drugs used for the treatment of patients with stable angina, acute myocardial infarction and chronic congestive heart failure. Long-term therapy with organic nitrates, however, results in a rapid development of nitrate tolerance blunting their hemodynamic and antiischemic efficacy. Recent studies revealed that mitochondrial reactive oxygen species (ROS) formation and a subsequent oxidative inactivation of nitrate reductase, the mitochondrial aldehyde dehydrogenase (ALDH-2), play an important role for the development of nitrate and crosstolerance. The present review focuses firstly on the role of ALDH-2 for organic nitrate bioactivation and secondly on the role of oxidative stress in the development of tolerance and cross-tolerance (endothelial dysfunction) in response to various organic nitrates. Finally, we would like to draw the reader's attention to the protective properties of the organic nitrate pentaerithrityl tetranitrate (PETN), which, in contrast to all other organic nitrates, is able to upregulate enzymes with a strong antioxidative capacity thereby preventing tolerance and the development of endothelial dysfunction.

Substrate binding site for nitrate reductase of Escherichia coli is on the inner aspect of the membrane.

PubMed Central

Kristjansson, J K; Hollocher, T C

1979-01-01

Escherichia coli grown anaerobically on nitrate exhibited the same transport barrier to reduction of chlorate, relative to nitrate, as that exhibited by Paracoccus denitrificans. This establishes that the nitrate binding site of nitrate reductase (EC 1.7.99.4) in E. coli must also lie on the cell side of the nitrate transporter which is associated with the plasma membrane. Because nitrate reductase is membrane bound, the nitrate binding site is thus located on the inner aspect of the membrane. Nitrate pulse studies on E. coli in the absence of valinomycin showed a small transient alkalinization (leads to H+/NO3- congruent to --0.07) which did not occur with oxygen pulses. By analogy with P. denitrificans, the alkaline transient is interpreted to arise from proton-linked nitrate uptake which is closely followed by nitrite efflux. The result is consistent with internal reduction of nitrate, whereas external reduction would be expected to give leads to H+/NO3-ratios approaching --2. PMID:374343

Nitrate biosensors and biological methods for nitrate determination.

PubMed

Sohail, Manzar; Adeloju, Samuel B

2016-06-01

The inorganic nitrate (NO3‾) anion is present under a variety of both natural and artificial environmental conditions. Nitrate is ubiquitous within the environment, food, industrial and physiological systems and is mostly present as hydrated anion of a corresponding dissolved salt. Due to the significant environmental and toxicological effects of nitrate, its determination and monitoring in environmental and industrial waters are often necessary. A wide range of analytical techniques are available for nitrate determination in various sample matrices. This review discusses biosensors available for nitrate determination using the enzyme nitrate reductase (NaR). We conclude that nitrate determination using biosensors is an excellent non-toxic alternative to all other available analytical methods. Over the last fifteen years biosensing technology for nitrate analysis has progressed very well, however, there is a need to expedite the development of nitrate biosensors as a suitable alternative to non-enzymatic techniques through the use of different polymers, nanostructures, mediators and strategies to overcome oxygen interference. Copyright © 2016 Elsevier B.V. All rights reserved.

Differential Effect of Irradiance and Nutrient Nitrate on the Relationship of in Vivo and in Vitro Nitrate Reductase Assay in Chlorophyllous Tissues 1

PubMed Central

Jones, Richard Wyn; Sheard, Robert W.

1977-01-01

Growth at increasing continuous irradiance (at high nutrient nitrate) and nutrient nitrate concentrations (at high continuous irradiance) furnished increases in the in vivo and in vitro nitrate reductase activities of corn (Zea mays L.), field peas (Pisum arvense L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and globe amaranth (Gomphrena globosa L.) leaves and of marrow (Cucurbita pepo L.) cotyledons. Ratios of in vivo to in vitro activity declined exponentially in all species with increasing nitrate reductase levels promoted by nutrient nitrate. The ratios were more nearly independent of nitrate reductase levels generated by adjusting the irradiance; major exceptions were marrow and wheat at low (1.5 klux and less) irradiances and peas throughout the irradiance range, where decreases in the ratio were accompanied by increases in in situ nitrate concentration. The ratio also increased at the highest irradiance (39.2 klux) in wheat and barley, associated with a decline of in vitro nitrate reductase. These differences in response to irradiance and nutrient nitrate indicate that the in vivo assay does not provide a simple measure of nitrate reductase but rather yields a more composite measure of nitrate reduction, possibly related both to nitrate reductase level and to the supply of reductant for in vivo activity. PMID:16659888

Observations of fine and coarse particle nitrate at several rural locations in the United States

NASA Astrophysics Data System (ADS)

Lee, Taehyoung; Yu, Xiao-Ying; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

Nitrate comprises an important part of aerosol mass at many non-urban locations during some times of the year. Little is known, however, about the chemical form and size distribution of particulate nitrate in these environments. While submicron ammonium nitrate is often assumed to be the dominant species, this assumption is rarely tested. Properties of aerosol nitrate were characterized at several IMPROVE monitoring sites during a series of field studies. Study sites included Bondville, Illinois (February 2003), San Gorgonio Wilderness Area, California (April and July 2003), Grand Canyon National Park, Arizona (May 2003), Brigantine National Wildlife Refuge, New Jersey (November 2003), and Great Smoky Mountains National Park, Tennessee (July/August 2004). Nitrate was found predominantly in submicron ammonium nitrate particles during the Bondville and San Gorgonio (April) campaigns. Coarse mode nitrate particles, resulting from reactions of nitric acid or its precursors with sea salt or soil dust, were more important at Grand Canyon and Great Smoky Mountains. Both fine and coarse mode nitrate were important during the studies at Brigantine and San Gorgonio (July). These results, which complement earlier findings about the importance of coarse particle nitrate at Yosemite and Big Bend National Parks, suggest a need to more closely examine common assumptions regarding the importance of ammonium nitrate at non-urban sites, to include pathways for coarse mode nitrate formation in regional models, and to consider impacts of coarse particle nitrate on visibility. Because coarse particle nitrate modes often extend well below 2.5 μm aerodynamic diameter, measurements of PM 2.5 nitrate in these environments should not automatically be assumed to contain only ammonium nitrate.

Ground-water movement and nitrate in ground water, East Erda area, Tooele County, Utah, 1997-2000

USGS Publications Warehouse

Susong, D.D.

2005-01-01

Nitrate was discovered in ground water in the east Erda area of Tooele County, Utah, in 1994. The U.S. Geological Survey, in cooperation with Tooele County, investigated the ground-water flow system and water quality in the eastern part of Tooele Valley to determine (1) the vertical and horizontal distribution of nitrate, (2) the direction of movement of the nitrate contamination, and (3) the source of the nitrate. The potentiometric surface of the upper part of the basin-fill aquifer indicates that the general direction of ground-water flow is to the northwest, the flow system is complex, and there is a ground-water mound probably associated with springs. The spatial distribution of nitrate reflects the flow system with the nitrate contamination split into a north and south part by the ground-water mound. The distribution of dissolved solids and sulfate in ground water varies spatially. Vertical profiles of nitrate in water from selected wells indicate that nitrate contamination generally is in the upper part of the saturated zone and in some wells has moved downward. Septic systems, mining and smelting, agriculture, and natural sources were considered to be possible sources of nitrate contamination in the east Erda area. Septic systems are not the source of nitrate because water from wells drilled upgradient of all septic systems in the area had elevated nitrate concentrations. Mining and smelting activity are a possible source of nitrate contamination but few data are available to link nitrate contamination with mining sites. Natural and agricultural sources of nitrate are present east of the Erda area but few data are available about these sources. The source(s) of nitrate in the east Erda area could not be clearly delineated in spite of considerable effort and expenditure of resources.

Geochemical controls on microbial nitrate-dependent U(IV) oxidation

USGS Publications Warehouse

Senko, John M.; Suflita, Joseph M.; Krumholz, Lee R.

2005-01-01

After reductive immobilization of uranium, the element may be oxidized and remobilized in the presence of nitrate by the activity of dissimilatory nitrate-reducing bacteria. We examined controls on microbially mediated nitrate-dependent U(IV) oxidation in landfill leachate-impacted subsurface sediments. Nitrate-dependent U(IV)-oxidizing bacteria were at least two orders of magnitude less numerous in these sediments than glucose- or Fe(II)-oxidizing nitrate-reducing bacteria and grew more slowly than the latter organisms, suggesting that U(IV) is ultimately oxidized by Fe(III) produced by nitrate-dependent Fe(II)-oxidizing bacteria or by oxidation of Fe(II) by nitrite that accumulates during organotrophic dissimilatory nitrate reduction. We examined the effect of nitrate and reductant concentration on nitrate-dependent U(IV) oxidation in sediment incubations and used the initial reductive capacity (RDC = [reducing equivalents] - [oxidizing equivalents]) of the incubations as a unified measurement of the nitrate or reductant concentration. When we lowered the RDC with progressively higher nitrate concentrations, we observed a corresponding increase in the extent of U(IV) oxidation, but did not observe this relationship between RDC and U(IV) oxidation rate, especially when RDC > 0, suggesting that nitrate concentration strongly controls the extent, but not the rate of nitrate-dependent U(IV) oxidation. On the other hand, when we raised the RDC in sediment incubations with progressively higher reductant (acetate, sulfide, soluble Fe(II), or FeS) concentrations, we observed progressively lower extents and rates of nitrate-dependent U(IV) oxidation. Acetate was a relatively poor inhibitor of nitrate-dependent U(IV) oxidation, while Fe(II) was the most effective inhibitor. Based on these results, we propose that it may be possible to predict the stability of U(IV) in a bioremediated aquifer based on the geochemical characteristics of that aquifer.

Post-anthesis nitrate uptake is critical to yield and grain protein content in Sorghum bicolor.

PubMed

Worland, Belinda; Robinson, Nicole; Jordan, David; Schmidt, Susanne; Godwin, Ian

2017-09-01

Crops only use ∼50% of applied nitrogen (N) fertilizer creating N losses and pollution. Plants need to efficiently uptake and utilize N to meet growing global food demands. Here we investigate how the supply and timing of nitrate affects N status and yield in Sorghum bicolor (sorghum). Sorghum was grown in pots with either 10mM (High) or 1mM (Low) nitrate supply. Shortly before anthesis the nitrate supply was either maintained, increased 10-fold or eliminated. Leaf sheaths of sorghum grown with High nitrate accumulated nitrate in concentrations >3-times higher than leaves. Removal of nitrate supply pre-anthesis resulted in the rapid reduction of stored nitrate in all organs. Plants receiving a 10-fold increase in nitrate supply pre-anthesis achieved similar grain yield and protein content and 29% larger grains than those maintained on High nitrate, despite receiving 24% less nitrate over the whole growth period. In sorghum, plant available N is important throughout development, particularly anthesis and grain filling, for grain yield and grain protein content. Nitrate accumulation in leaf sheaths presents opportunities for the genetic analysis of mechanisms behind nitrate storage and remobilization in sorghum to improve N use efficiency. Copyright © 2017 Elsevier GmbH. All rights reserved.

Dietary nitrate as modulator of physical performance and cardiovascular health.

PubMed

Kerley, Conor P

2017-11-01

Early interventional trials reported improvements in cardiac and exercise outcomes with inorganic nitrate ingestion. The current review aims to provide a brief update of recent evidence regarding ergogenic and cardiovascular effects of dietary nitrate and practical recommendations. Recent evidence has been inconsistent and questions remain regarding effective dose, duration, and source of nitrate and cohorts likely to benefit. Dietary nitrate may be most relevant to those with vascular/metabolic impairments, those engaging in short-term, intense exercise, deconditioned individuals, and those with a low dietary nitrate intake. The evidence for cardiovascular/exercise benefit is plausible but inconsistent. However, dietary nitrate, in contrast to pharmacological nitrate, has a high benefit-risk ratio. Although nitrate supplementation has grown in popularity, it is suggested that increased green vegetables consumption may provide similar/superior benefits to nitrate supplementation in a cheaper, safer, and potentially tastier context.

HANS SELYE: AN INSPIRING TEACHER.

PubMed

Gabbiani, Giulio

2014-03-30

The present writing is a recollection of Hans Selye, as an educator of graduate and post-graduate students. His main aim in teaching his students was to encourage originality and significance of all scientific research.

Space and Missile Systems Center Compliance Specifications and Standards

DTIC Science & Technology

2015-07-31

Brown United Launch Alliance wayne.brown@ulalaunch.co m Mike Jensen United Launch Alliance mike.jensen@ulalaunch.com Hans Koenigsmann SpaceX ...Hans.Koenigsmann@ spacex . com APPROVED BY_________________________________________________________________ DATE_______________ (AF OFFICE)

Melancholy, Acculturation, and Relief: A Brief Essay on the Religion of Ordinarity.

PubMed

Shin, Hyon-Uk

2018-04-01

Han is not an idiosyncratic, psychological experience that is peculiar to Koreans, but a multifaceted mode of melancholy experienced by many and various people. What makes this psychological experience particularly familiar to Koreans, however, is that this phenomenon is colored by various, macroscopic factors common in the Korean context, such as sociocultural rigidness, historical instability, political feudality, and economic vulnerability. In this sense, han is an acculturated, multifaceted melancholy. Not only that, it has developed its own religiousness, the goal of which is the restoration of ordinarity, because the state of han premises extraordinary, abnormal, or tension-provoking situations. The explicit and implicit religious idioms developing in the religion of han, such as tongsung-kido and wishing-for-blessing, evolve around this religious telos, helping individuals in Korea restore and live ordinarity.

Genetic polymorphism of the 26 short tandem repeat loci in the Chinese Hebei Han population using two commercial forensic kits.

PubMed

Lei, Liang; Xu, Jie; Du, Qingqing; Fu, Lihong; Zhang, Xiaojing; Yu, Feng; Ma, Chunling; Cong, Bin; Li, Shujin

2015-01-01

We determined the allele frequencies and forensic parameters for the 26 short tandem repeat (STR) autosomal markers in two commercial kits (the Investigator HDplex and AmpFLSTR(®) Identifiler(®) systems) for 183 unrelated individuals from the Han population of the Hebei Province of China. The 26 STRs were all in Hardy-Weinberg equilibrium. No linkage disequilibrium was detected between any pair of loci. The combined power of discrimination and the combined power of exclusion for the 26 STR loci were 1-7.74E-31 and 1-1.21E-11, respectively. Six rare alleles of D10S2325 were identified and named 20, 21, 22, 23, 24, and 31. All the length of the six rare alleles were out of the range of allelic ladder. We calculated the population pairwise genetic distance based on the allele frequencies, using published population data including German, central Polish, south Dutch, northeastern Polish, south Brazilian, Korean, Sichuan Han of China, and Shanghai Han of China. Also we examined the population pairwise genetic distance of loci included in Identifiler system between Hebei Han and other ethnic population of China. These 26 autosomal STR loci could provide highly informative polymorphic data for paternity testing and forensic identification in the Hebei Han population in China. Because they are all in linkage equilibrium, they could be used together to solve deficient kinship cases or cases with mutations.

Forensic genetic informativeness of an SNP panel consisting of 19 multi-allelic SNPs.

PubMed

Gao, Zehua; Chen, Xiaogang; Zhao, Yuancun; Zhao, Xiaohong; Zhang, Shu; Yang, Yiwen; Wang, Yufang; Zhang, Ji

2018-05-01

Current research focusing on forensic personal identification, phenotype inference and ancestry information on single-nucleotide polymorphisms (SNPs) has been widely reported. In the present study, we focused on tetra-allelic SNPs in the Chinese Han population. A total of 48 tetra-allelic SNPs were screened out from the Chinese Han population of the 1000 Genomes Database, including Chinese Han in Beijing (CHB) and Chinese Han South (CHS). Considering the forensic genetic requirement for the polymorphisms, only 11 tetra-allelic SNPs with a heterozygosity >0.06 were selected for further multiplex panel construction. In order to meet the demands of personal identification and parentage identification, an additional 8 tri-allelic SNPs were combined into the final multiplex panel. To ensure application in the degraded DNA analysis, all the PCR products were designed to be 87-188 bp. Employing multiple PCR reactions and SNaPshot minisequencing, 511 unrelated Chinese Han individuals from Sichuan were genotyped. The combined match probability (CMP), combined discrimination power (CDP), and cumulative probability of exclusion (CPE) of the panel were 6.07 × 10 -11 , 0.9999999999393 and 0.996764, respectively. Based on the population data retrieved from the 1000 Genomes Project, Fst values between Chinese Han in Sichuan (SCH) and all the populations included in the 1000 Genomes Project were calculated. The results indicated that two SNPs in this panel may contain ancestry information and may be used as markers of forensic biogeographical ancestry inference. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous reduction of nitrate and selenate by cell suspensions of selenium-respiring bacteria

USGS Publications Warehouse

Oremland, R.S.; Blum, J.S.; Bindi, A.B.; Dowdle, P.R.; Herbel, M.; Stolz, J.F.

1999-01-01

Washed-cell suspensions of Sulfurospirillum barnesii reduced selenate [Se(VI)] when cells were cultured with nitrate, thiosulfate, arsenate, or fumarate as the electron acceptor. When the concentration of the electron donor was limiting, Se(VI) reduction in whole cells was approximately fourfold greater in Se(VI)-grown cells than was observed in nitrate-grown cells; correspondingly, nitrate reduction was ~11-fold higher in nitrate-grown cells than in Se(VI)-grown cells. However, a simultaneous reduction of nitrate and Se(VI) was observed in both cases. At nonlimiting electron donor concentrations, nitrate- grown cells suspended with equimolar nitrate and selenate achieved a complete reductive removal of nitrogen and selenium oxyanions, with the bulk of nitrate reduction preceding that of selenate reduction. Chloramphenicol did not inhibit these reductions. The Se(VI)-respiring haloalkaliphile Bacillus arsenicoselenatis gave similar results, but its Se(VI) reductase was not constitutive in nitrate-grown cells. No reduction of Se(VI) was noted for Bacillus selenitireducens, which respires selenite. The results of kinetic experiments with cell membrane preparations of S. barnesii suggest the presence of constitutive selenate and nitrate reduction, as well as an inducible, high- affinity nitrate reductase in nitrate-grown cells which also has a low affinity for selenate. The simultaneous reduction of micromolar Se(VI) in the presence of millimolar nitrate indicates that these organisms may have a functional use in bioremediating nitrate-rich, seleniferous agricultural wastewaters. Results with 75Se-selenate tracer show that these organisms can lower ambient Se(VI) concentrations to levels in compliance with new regulations proposed for release of selenium oxyanions into the environment.

Study on the influence of the decoking agent on the activity of limestone in wet flue gas desulfurization

NASA Astrophysics Data System (ADS)

Li, Qianjun; Xu, Dongyang; Wu, Yunxia; Yu, Jin

2017-01-01

Influence of the main components of decoking agent (magnesium nitrate, aluminum nitrate, copper nitrate, ammonium nitrate and actual decoking agent) on the activity of limestone is studied in laboratory by MET method. Results show that magnesium nitrate, ammonium nitrate and copper nitrate almost has no effect on the activity of limestone. With the concentration increasing, aluminum nitrate has an increasing inhibition on the dissolution of limestone. Fly ash has inhibition on dissolution of limestone due to the blockage of limestone pore by fly ash. The actual decoking agent has almost no effect on the limestone.

Organic Nitrates: A Complex Family of Atmospheric Trace Constituents

NASA Astrophysics Data System (ADS)

Ballschmiter, K.; Fischer, R. G.; Grünert, A.; Kastler, J.; Schneider, M.; Woidich, S.

2003-04-01

Biogenic and geogenic hydrocarbons are the precursors of organic nitrates that are formed as tropospheric photo-oxidation products in the presence of NOx. Air chemistry leads to a very complex pattern of nitric acid esters: alkyl nitrates, aryl-alkyl nitrates, and bifunctional nitrates like alkyl dinitrates, hydroxy alkyl nitrates and carbonyl alkyl nitrates. We have analyzed the pattern of organic nitrates in air samples after adsorption/thermal desorption (low volume sampling-LVS) or adsorption/solvent desorption (high volume sampling-HVS) by capillary gas chromatography with electron capture (ECD) and mass spectrometric detection (MSD) using air aliquotes of 100 up to 3000 liters on column. The complexity of the organic nitrates found in air requires a group pre-separation by normal phase liquid chromatography. A detection limit per compound of 0.005 ppt(v) is achieved by our approach. We have synthesized a broad spectrum of organic nitrates as reference compounds. Air samples were taken from central Europe, the US West (Utah, Nevada, California), and the North- and South Atlantic including Antarctica. Levels and patterns of the regional and global occurrence of the various groups of C1-C12 organic nitrates including dinitrates and hydroxy nitrates and nitrates of isoprene (2-methylbutadiene) are presented. Werner G., J. Kastler, R. Looser, K. Ballschmiter: "Organic nitrates of isoprene as atmospheric trace compounds" Angewandte Chemie - International Edition (1999) 38: 1634-1637. Woidich S., O. Froescheis, O. Luxenhofer, K. Ballschmiter: "EI- and NCI-mass spectrometry of arylalkyl nitrates and their occurrence in urban air" Fresenius J. Anal. Chem. (1999) 364 : 91-99. Kastler, J; Jarman, W; Ballschmiter, K.: "Multifunctional organic nitrates as constituents in European and US urban photo-smog" Fresenius J. Anal. Chem. (2000) 368:244-249. Schneider M., K. Ballschmiter: "C3-C14 alkyl nitrates in remote South Atlantic air" Chemosphere (1999) 38: 233-244. Fischer, R G; Kastler, J; Ballschmiter, K.: "Levels and pattern of alkyl nitrates, multifunctional alkyl nitrates, and halocarbons in the air over the Atlantic Ocean" J. Geophys. Research (2000) 105:14473-14494. Fischer R.G. , R. Weller, H.-W. Jacobi, K. Ballschmiter: "Levels and patterns of volatile organic nitrates and halocarbons in the air at Neumayer Station (70°), Antarctic" Chemosphere (2002) 48:981-992

Peroxisome proliferator-activated receptor delta +294T > C polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

PubMed Central

2010-01-01

Background The association of peroxisome proliferator-activated receptor delta (PPARD) +294T > C polymorphism and serum lipid levels is inconsistent in several previous studies. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The present study was undertaken to detect the association of PPARD +294T > C (rs2016520) polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations. Methods A total of 609 subjects of Bai Ku Yao and 573 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the PPARD +294T > C polymorphism was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. Results The levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), apolipoprotein (Apo) AI and ApoB were lower in Bai Ku Yao than in Han (P < 0.001 for all). The frequency of T and C alleles was 77.50% and 22.50% in Bai Ku Yao, and 72.43% and 27.57% in Han (P < 0.01); respectively. The frequency of TT, TC and CC genotypes was 60.59%, 33.83% and 5.53% in Bai Ku Yao, and 52.18%, 40.50% and 7.32% in Han (P < 0.05); respectively. The subjects with CC genotype in Bai Ku Yao had higher serum LDL-C and ApoB levels and lower the ratio of ApoAI to ApoB than the subjects with TT and TC genotypes in females but not in males. The C allele carriers in Han had higher serum TC levels in males (P < 0.01) and ApoB levels in females (P < 0.05) than the C allele noncarriers. Serum TC and ApoB levels were correlated with genotypes in Han (P < 0.05 for each) but not in Bai Ku Yao. Serum lipid parameters were also correlated with sex, age, body mass index, alcohol consumption, cigarette smoking, and blood pressure in both ethnic groups. Conclusions These results suggest that the association of PPARD +294T > C polymorphism and serum lipid levels is different between the Bai Ku Yao and Han populations. The discrepancy between the two ethnic groups might partly result from different PPARD +294T > C polymorphism or PPARD gene-enviromental interactions. PMID:21176135

Dietary nitrate protects submandibular gland from hyposalivation in ovariectomized rats via suppressing cell apoptosis.

PubMed

Xu, Yipu; Pang, Baoxing; Hu, Liang; Feng, Xiaoyu; Hu, Lei; Wang, Jingsong; Zhang, Chunmei; Wang, Songlin

2018-02-26

Xerostomia, a major oral symptom of menopause, is a subjective feeling of dry mouth associated with oral pain and difficulties in deglutition and speech, which significantly reduces patient's quality of life. Dietary nitrate, which can be converted to nitric oxide, has multiple physiological functions in the body, including antioxidant activity and vasodilatation; however, its protective effect against xerostomia remains poorly understood. The present study aimed to evaluate the effects of dietary nitrate on estrogen deficiency-induced xerostomia. We established an ovariectomized (OVX) rat model, which included five groups: sham-operated, OVX, OVX + 0.4 mM nitrate, OVX + 2 mM nitrate, and OVX + 4 mM nitrate (n = 6). After ovariectomy, animals in the nitrate treatment groups received appropriate amounts of sodium nitrate dissolved in distilled water for 3 months. The results showed that nitrate treatment reduced body weight and water intake, and increased serum nitrate and nitrite levels. Furthermore, nitrate uptake increased saliva secretion as evidenced by saliva flow rates and aquaporin 5 expression, and alleviated histological lesions as evidenced by reduction of the fibrotic area and cell atrophy in the salivary glands. Although protective effects of nitrate against estrogen deficiency-induced xerostomia were observed at all doses, treatment with 2 mM nitrate was more effective than that with 0.4 mM and 4 mM nitrate. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 expression analyses showed that nitrate also protected cells from apoptosis, possibly through upregulation of Cu-Zn superoxide dismutase (Cu-Zn SOD) known to inhibit oxidative stress-related apoptosis. Our findings indicate that nitrate could improve functional activity of the salivary glands in OVX rats by suppressing apoptosis and upregulating Cu-Zn SOD expression, suggesting that dietary nitrate may potentially prevent hyposalivation in menopausal women. Copyright © 2018. Published by Elsevier Inc.

Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. Why?

PubMed Central

Papaspyrou, Sokratis; Smith, Cindy J.; Dong, Liang F.; Whitby, Corinne; Dumbrell, Alex J.; Nedwell, David B.

2014-01-01

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases. PMID:24728381

Oxygen and nitrogen isotopic composition of nitrate in commercial fertilizers, nitric acid, and reagent salts.

PubMed

Michalski, Greg; Kolanowski, Michelle; Riha, Krystin M

2015-01-01

Nitrate is a key component of synthetic fertilizers that can be beneficial to crop production in agro-ecosystems, but can also cause damage to natural ecosystems if it is exported in large amounts. Stable isotopes, both oxygen and nitrogen, have been used to trace the sources and fate of nitrate in various ecosystems. However, the oxygen isotope composition of synthetic and organic nitrates is poorly constrained. Here, we present a study on the N and O isotope composition of nitrate-based fertilizers. The δ(15)N values of synthetic and natural nitrates were 0 ± 2 ‰ similar to the air N2 from which they are derived. The δ(18)O values of synthetic nitrates were 23 ± 3 ‰, similar to air O2, and natural nitrate fertilizer δ(18)O values (55 ± 5 ‰) were similar to those observed in atmospheric nitrate. The Δ(17)O values of synthetic fertilizer nitrate were approximately zero following a mass-dependent isotope relationship, while natural nitrate fertilizers had Δ(17)O values of 18 ± 2 ‰ similar to nitrate produced photochemically in the atmosphere. These narrow ranges of values can be used to assess the amount of nitrate arising from fertilizers in mixed systems where more than one nitrate source exists (soil, rivers, and lakes) using simple isotope mixing models.

Challenges with nitrate therapy and nitrate tolerance: prevalence, prevention, and clinical relevance.

PubMed

Thadani, Udho

2014-08-01

Nitrate therapy has been an effective treatment for ischemic heart disease for over 100 years. The anti-ischemic and exercise-promoting benefits of sublingually administered nitrates are well established. Nitroglycerin is indicated for the relief of an established attack of angina and for prophylactic use, but its effects are short lived. In an effort to increase the duration of beneficial effects, long-acting orally administered and topical applications of nitrates have been developed; however, following their continued or frequent daily use, patients soon develop tolerance to these long-acting nitrate preparations. Once tolerance develops, patients begin losing the protective effects of the long-acting nitrate therapy. By providing a nitrate-free interval, or declining nitrate levels at night, one can overcome or reduce the development of tolerance, but cannot provide 24-h anti-anginal and anti-ischemic protection. In addition, patients may be vulnerable to occurrence of rebound angina and myocardial ischemia during periods of absent nitrate levels at night and early hours of the morning, and worsening of exercise capacity prior to the morning dose of the medication. This has been a concern with nitroglycerin patches but not with oral formulations of isosorbide-5 mononitrates, and has not been adequately studied with isosorbide dinitrate. This paper describes problems associated with nitrate tolerance, reviews mechanisms by which nitrate tolerance and loss of efficacy develop, and presents strategies to avoid nitrate tolerance and maintain efficacy when using long-acting nitrate formulations.

Effect of filters and reconstruction algorithms on I-124 PET in Siemens Inveon PET scanner

NASA Astrophysics Data System (ADS)

Ram Yu, A.; Kim, Jin Su

2015-10-01

Purpose: To assess the effects of filtering and reconstruction on Siemens I-124 PET data. Methods: A Siemens Inveon PET was used. Spatial resolution of I-124 was measured to a transverse offset of 50 mm from the center FBP, 2D ordered subset expectation maximization (OSEM2D), 3D re-projection algorithm (3DRP), and maximum a posteriori (MAP) methods were tested. Non-uniformity (NU), recovery coefficient (RC), and spillover ratio (SOR) parameterized image quality. Mini deluxe phantom data of I-124 was also assessed. Results: Volumetric resolution was 7.3 mm3 from the transverse FOV center when FBP reconstruction algorithms with ramp filter was used. MAP yielded minimal NU with β =1.5. OSEM2D yielded maximal RC. SOR was below 4% for FBP with ramp, Hamming, Hanning, or Shepp-Logan filters. Based on the mini deluxe phantom results, an FBP with Hanning or Parzen filters, or a 3DRP with Hanning filter yielded feasible I-124 PET data.Conclusions: Reconstruction algorithms and filters were compared. FBP with Hanning or Parzen filters, or 3DRP with Hanning filter yielded feasible data for quantifying I-124 PET.

IL2RA Allele Increases Risk of Neuromyelitis Optica in Southern Han Chinese.

PubMed

Dai, Yongqiang; Li, Jin; Zhong, Xiaonan; Wang, Yuge; Qiu, Wei; Lu, Zhengqi; Wu, Aimin; Bao, Jian; Peng, Fuhua; Hu, Xueqiang

2013-11-01

Neuromyelitis optica (NMO) and multiple sclerosis (MS) are chronic neuro-inflammatory diseases believed to arise from complex interactions between environmental and genetic factors. Recently, single nucleotide polymorphisms (SNPs) in interleukin (IL)-2 and -7 receptor alpha genes have been identified as novel susceptibility alleles for MS in genome-wide association studies. However, similar research on NMO is limited. We aimed to investigate the association of IL2RA SNPs rs2104286 and rs12722489 and IL7RA SNP rs6897932 with Southern Han Chinese NMO and MS patients. Frequencies of the three SNPs were examined in Southern Han Chinese mS cases (n=78), NMS cases (n=67) and controls (n=133) using sequencing-based typing. The rs2104286(G) frequency in the IL2RA gene was significantly higher in NMO patients than in controls (p(uncorr)=0.013, p(corr)=0.026, OR:1.942, 95%CI:1.146-3.291). The rs2104286 G allele in IL2RA is present at higher frequencies in NMO patients than in healthy controls within a Southern Han Chinese population. Les allèles IL2RA augmentent le risque de neuromyélite optique chez les Chinois Han du sud.

Prevalence of Obesity and Related Factors among Bouyei and Han Peoples in Guizhou Province, Southwest China.

PubMed

Wang, Ke; Wang, Dingming; Pan, Li; Yu, Yangwen; Dong, Fen; Li, Ling; Wang, Li; Liu, Tao; Zeng, Xianjia; Sun, Liangxian; Zhu, Guangjin; Feng, Kui; Jonasson, Junmei Miao; Wu, Zhenglai; Xu, Ke; Pang, Xinglong; Chen, Ting; Pan, Hui; Ma, Jin; Zhong, Yong; Ping, Bo; Shan, Guangliang

2015-01-01

To investigate the prevalence of general and abdominal obesity and associated factors in Bouyei and Han peoples. A cross-sectional study was carried out in Guizhou province, southwest China in 2012, with multi-stage sampling to enroll 4551 participants aged 20 to 80 years. General and abdominal obesity were defined by World Health Organization (WHO) for Chinese. A design-based analysis was performed to evaluate prevalence of obesity and its related factors. Bouyei people had a significantly lower prevalence of general obesity (4.8% vs. 10.9%, p < 0.05) and abdominal obesity (13.6% vs. 26.8%, p < 0.05) than that in Han people. Prevalence of obesity increased with age until middle-age period and declined thereafter. Men aged 40-49 years group and women aged 50-59 years group have the highest prevalence of general obesity. Prevalence of abdominal obesity was higher than that of general obesity. Middle-age, Higher income, Han people were significantly associated with an increased risk of General/abdominal obesity. Bouyei people had a lower prevalence of general and abdominal obesity than the Han people. Etiological studies should be conducted to determine underlying genetic factors and dietary factors.

Differential responses of autonomic function in sea level residents, acclimatized lowlanders at >3500 m and Himalayan high altitude natives at >3500 m: A cross-sectional study.

PubMed

Dhar, Priyanka; Sharma, Vijay K; Das, Saroj K; Barhwal, Kalpana; Hota, Sunil K; Singh, Shashi B

2018-04-09

We studied the differential responses of autonomic function in sea level residents (SLR), acclimatized lowlanders (ALH) in high altitude (HA) and HA natives (HAN) at >3500 m. Out of 771 male volunteers included in this cross-sectional study, SLR, ALH and HAN groups were comprised of 351, 307 and 113 volunteers, respectively. Our results showed persistent sympathetic dominance with significantly reduced (p < 0.05) parasympathetic response in ALH as compared to SLR and HAN populations. This may be attributed to significantly increased (p < 0.05) concentration of coronary risk factors and plasma catecholamines in ALH as compared to SLR and HAN. The ALH also showed significantly increased (p < 0.05) level of serum homocysteine as compared to SLR. The HAN exhibited no changes in autonomic function despite significantly elevated (p < 0.05) homocysteine level as compared to SLR. Our findings may have clinical relevance for assessment of susceptibility to cardiovascular risks in HA dwellers, native highlanders and patients with hypoxemia. Copyright © 2018 Elsevier B.V. All rights reserved.

Microbial community development on the surface of Hans and Werenskiold Glaciers (Svalbard, Arctic): a comparison.

PubMed

Grzesiak, Jakub; Górniak, Dorota; Świątecki, Aleksander; Aleksandrzak-Piekarczyk, Tamara; Szatraj, Katarzyna; Zdanowski, Marek K

2015-09-01

Surface ice and cryoconite holes of two types of polythermal Svalbard Glaciers (Hans Glacier--grounded tidewater glacier and Werenskiold Glacier-land-based valley glacier) were investigated in terms of chemical composition, microbial abundance and diversity. Gathered data served to describe supraglacial habitats and to compare microbe-environment interactions on those different type glaciers. Hans Glacier samples displayed elevated nutrient levels (DOC, nitrogen and seston) compared to Werenskiold Glacier. Adjacent tundra formations, bird nesting sites and marine aerosol were candidates for allochtonic enrichment sources. Microbial numbers were comparable on both glaciers, with surface ice containing cells in the range of 10(4) mL(-1) and cryoconite sediment 10(8) g(-1) dry weight. Denaturating gradient gel electrophoresis band-based clustering revealed differences between glaciers in terms of dominant bacterial taxa structure. Microbial community on Werenskiold Glacier benefited from the snow-released substances. On Hans Glacier, this effect was not as pronounced, affecting mainly the photoautotrophs. Over-fertilization of Hans Glacier surface was proposed as the major factor, desensitizing the microbial community to the snow melt event. Nitrogen emerged as a limiting factor in surface ice habitats, especially to Eukaryotic algae.

Presence of nitrate NO 3 a ects animal production, photocalysis is a possible solution

NASA Astrophysics Data System (ADS)

Barba-Molina, Heli; Barba-Ortega, J.; Joya, M. R.

2016-02-01

Farmers and ranchers depend on the successful combination of livestock and crops. However, they have lost in the production by nitrate pollution. Nitrate poisoning in cattle is caused by the consumption of an excessive amount of nitrate or nitrite from grazing or water. Both humans and livestock can be affected. It would appear that well fertilised pasture seems to take up nitrogen from the soil and store it as nitrate in the leaf. Climatic conditions, favour the uptake of nitrate. Nitrate poisoning is a noninfectious disease condition that affects domestic ruminants. It is a serious problem, often resulting in the death of many animals. When nitrogen fertilizers are used to enrich soils, nitrates may be carried by rain, irrigation and other surface waters through the soil into ground water. Human and animal wastes can also contribute to nitrate contamination of ground water. A possible method to decontaminate polluted water by nitrates is with methods of fabrication of zero valent iron nanoparticles (FeNps) are found to affect their efficiency in nitrate removal from water.

Total salivary nitrates and nitrites in oral health and periodontal disease.

PubMed

Sánchez, Gabriel A; Miozza, Valeria A; Delgado, Alejandra; Busch, Lucila

2014-01-30

It is well known that nitrites are increased in saliva from patients with periodontal disease. In the oral cavity, nitrites may derive partly from the reduction of nitrates by oral bacteria. Nitrates have been reported as a defence-related mechanism. Thus, the aim of the present study was to determine the salivary levels of total nitrate and nitrite and their relationship, in unstimulated and stimulated saliva from periodontal healthy subjects, and from patients with chronic periodontal disease. Nitrates and nitrites were determined in saliva from thirty healthy subjects and forty-four patients with periodontal disease. A significant increase in salivary nitrates and nitrites was observed. Nitrates and nitrites concentration was related to clinical attachment level (CAL). A positive and significant Pearson's correlation was found between salivary total nitrates and nitrites. Periodontal treatment induced clinical improvement and decreased nitrates and nitrites. It is concluded that salivary nitrates and nitrites increase, in patients with periodontal disease, could be related to defence mechanisms. The possibility that the salivary glands respond to oral infectious diseases by increasing nitrate secretion should be explored further. Copyright © 2013 Elsevier Inc. All rights reserved.

Assessing the Role of Sewers and Atmospheric Deposition as Nitrate Contamination Sources to Urban Surface Waters using Stable Nitrate Isotopes

NASA Astrophysics Data System (ADS)

Sikora, M. T.; Elliott, E. M.

2009-12-01

Excess nitrate (NO3-) contributes to the overall degraded quality of streams in many urban areas. These systems are often dominated by impervious surfaces and storm sewers that can route atmospherically deposited nitrogen, from both wet and dry deposition, to waterways. Moreover, in densely populated watersheds there is the potential for interaction between urban waterways and sewer systems. The affects of accumulated nitrate in riverine and estuary systems include low dissolved oxygen, loss of species diversity, increased mortality of aquatic species, and general eutrophication of the waterbody. However, the dynamics of nitrate pollution from each source and it’s affect on urban waterways is poorly constrained. The isotopes of nitrogen and oxygen in nitrate have been proven effective in helping to distinguish contamination sources to ground and surface waters. In order to improve our understanding of urban nitrate pollution sources and dynamics, we examined nitrate isotopes (δ15N and δ18O) in base- and stormflow samples collected over a two-year period from a restored urban stream in Pittsburgh, Pennsylvania (USA). Nine Mile Run drains a 1,600 hectare urban watershed characterized by 38% impervious surface cover. Prior work has documented high nitrate export from the watershed (~19 kg NO3- ha-1 yr-1). Potential nitrate sources to the watershed include observed sewer overflows draining directly to the stream, as well as atmospheric deposition (~23 kg NO3- ha-1 yr-1). In this and other urban systems with high percentages of impervious surfaces, there is likely minimal input from nitrate derived from soil or fertilizer. In this presentation, we examine spatial and temporal patterns in nitrate isotopic composition collected at five locations along Nine Mile Run characterized by both sanitary and combined-sewer cross-connections. Preliminary isotopic analysis of low-flow winter streamwater samples suggest nitrate export from Nine Mile Run is primarily influenced by inputs of human waste despite high rates of atmospheric nitrate deposition. Further isotopic analysis of nitrate will examine seasonal variations in nitrate sources; compare nitrate dynamics and sources during low- versus high-flows, and the influence of interannual climatic variability on nitrate export.

Effects of nitrate addition to a diet on fermentation and microbial populations in the rumen of goats, with special reference to Selenomonas ruminantium having the ability to reduce nitrate and nitrite.

PubMed

Asanuma, Narito; Yokoyama, Shota; Hino, Tsuneo

2015-04-01

This study investigated the effects of dietary nitrate addition on ruminal fermentation characteristics and microbial populations in goats. The involvement of Selenomonas ruminantium in nitrate and nitrite reduction in the rumen was also examined. As the result of nitrate feeding, the total concentration of ruminal volatile fatty acids decreased, whereas the acetate : propionate ratio and the concentrations of ammonia and lactate increased. Populations of methanogens, protozoa and fungi, as estimated by real-time PCR, were greatly decreased as a result of nitrate inclusion in the diet. There was modest or little impact of nitrate on the populations of prevailing species or genus of bacteria in the rumen, whereas Streptococcus bovis and S. ruminantium significantly increased. Both the activities of nitrate reductase (NaR) and nitrite reductase (NiR) per total mass of ruminal bacteria were increased by nitrate feeding. Quantification of the genes encoding NaR and NiR by real-time PCR with primers specific for S. ruminantium showed that these genes were increased by feeding nitrate, suggesting that the growth of nitrate- and nitrite-reducing S. ruminantium is stimulated by nitrate addition. Thus, S. ruminantium is likely to play a major role in nitrate and nitrite reduction in the rumen. © 2014 Japanese Society of Animal Science.

Test/QA Plan for Verification of Nitrate Sensors for Groundwater Remediation Monitoring

EPA Science Inventory

A submersible nitrate sensor is capable of collecting in-situ measurements of dissolved nitrate concentrations in groundwater. Although several types of nitrate sensors currently exist, this verification test will focus on submersible sensors equipped with a nitrate-specific ion...

Ipso Nitration. Regiospecific Nitration via Ipso Nitration Products.

DTIC Science & Technology

1985-05-20

products of nitration of alkylbenzenes and alkylphenol derivatives. The general pattern envisioned is shown in Scheme 1. In order to realize this...we have also explored solid state nitration of various alkylphenols . This procedure involves adsorbing concentrated nitric acid on alumina, followed

SEPARATION OF THORIUM FROM URANIUM

DOEpatents

Bane, R.W.

1959-09-01

A description is given for the separation of thorium from uranium by forming an aqueous acidic solution containing ionic species of thorium, uranyl uranium, and hydroxylamine, flowing the solution through a column containing the phenol-formaldehyde type cation exchange resin to selectively adsorb substantially all the thorium values and a portion of the uranium values, flowing a dilute solution of hydrochloric acid through the column to desorb the uranium values, and then flowing a dilute aqueous acidic solution containing an ion, such as bisulfate, which has a complexing effect upon thortum through the column to desorb substantially all of the thorium.

Process for making surfactant capped metal oxide nanocrystals, and products produced by the process

DOEpatents

Alivisatos, A. Paul; Rockenberger, Joerg

2006-01-10

Disclosed is a process for making surfactant capped nanocrystals of metal oxides which are dispersable in organic solvents. The process comprises decomposing a metal cupferron complex of the formula M^XCup_X, wherein M is a metal, and Cup is a N-substituted N-Nitroso hydroxylamine, in the presence of a coordinating surfactant, the reaction being conducted at a temperature ranging from about 150 to about 400.degree. C., for a period of time sufficient to complete the reaction. Also disclosed are compounds made by the process.

Theoretical performance of some rocket propellants containing hydrogen, nitrogen, and oxygen

NASA Technical Reports Server (NTRS)

Miller, Riley O; Ordin, Paul M

1948-01-01

Theoretical performance data including nozzle-exit temperature, specific impulse, volume specific impulse and composition, temperature, and mean molecular weight of reaction products based on frozen equilibrium and isentropic expansion are presented for 13 propellant combinations at reaction pressure of 300 pounds per square inch absolute and expansion ratio of 20.4. On basis of maximum specific impulse alone, five fuels had the following order for any given oxidant: liquid hydrogen, hydrazine, liquid ammonia, and either hydrazine hydrate or hydroxylamine. Three oxidants with a given fuel had the following order: liquid ozone, liquid oxygen, and 100-percent hydrogen peroxide.

Comment on "Combination of cupric ion with hydroxylamine and hydrogen peroxide for the control of bacterial biofilms on RO membranes by Hye-Jin Lee, Hyung-Eun Kim, Changha Lee [Water Research 110, 2017, 83-90]".

PubMed

Chen, Long; Peng, Ying; Tang, Min; Wu, Feng

2017-07-01

The methodology employed by Lee et al. to terminate their bactericidal assays was found to be flawed via our demonstrations. Briefly, EDTA or sulfite combining with cupric ion did not fully terminate, and instead even boosted the P. aeruginosa death. We therefore suggested them to seek for other means of reaction termination, such as the combination of buffering agent PBS and Cu(II)-complexing agent EDTA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mechanism of the mutagenic action of hydroxylamine. IX. The UV-induced cleavage of the N-O bond in N4-hydroxy-and N4-methoxycytidine and N6-methoxyadenosine.

PubMed Central

Simukova, N A; Yakovlev, D Y; Budowsky, E I

1975-01-01

The principal UV-induced (lambda = 2546nm) reaction of N4-hydroxy- and N4methoxycytidines and N6-methoxyadenosine in neutral aqueous solutions is cleavage of the exocyclic N-O bond with the respective formation of cytidine and adenosine. Quantum yields are 2.8x10(-3) and 2.2x10(-3) M/E for the first two compounds and 9.1x10(-3) M/E for N6-methoxyadenosine. PMID:1052542

CONCENTRATION OF Pu USING OXALATE TYPE CARRIER

DOEpatents

Ritter, D.M.; Black, R.P.S.

1960-04-19

A method is given for dissolving and reprecipitating an oxalate carrier precipitate in a carrier precipitation process for separating and recovering plutonium from an aqueous solution. Uranous oxalate, together with plutonium being carried thereby, is dissolved in an aqueous alkaline solution. Suitable alkaline reagents are the carbonates and oxulates of the alkali metals and ammonium. An oxidizing agent selected from hydroxylamine and hydrogen peroxide is then added to the alkaline solution, thereby oxidizing uranium to the hexavalent state. The resulting solution is then acidified and a source of uranous ions provided in the acidified solution, thereby forming a second plutoniumcarrying uranous oxalate precipitate.

Chemical Reactivity of Cyanogen Chloride in Aqueous Solution.

DTIC Science & Technology

1973-02-01

were found. The interaction between cobalt(II), manganese(lI), chromium (II) has been studied spectrophotometrically and some results are included in...x ±0 3 15 Arsenate 10 6.77 3.2 x 16 y- Picoline 0.25 - 0.15 8.8 - 9.5 6.0 50.4 17 Hydroxylamine 0.21 - 0.15 3.5 - 4.0 5.96 3.7 x 16 18 Pyridine 0.15...II), chromium (Il) has been studied * spectruphotometrically and some results are included in this report. e ,II ,I SD,’°Q4 4 ,1473 REPLA.S CD OROll4

Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2016-05-03

A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Foam-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2015-06-02

Foam-based adsorbents and a related method of manufacture are provided. The foam-based adsorbents include polymer foam with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the foam-based adsorbents includes irradiating polymer foam, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Foam-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Surface-enhanced Raman scattering and DFT investigation of Eriochrome Black T metal chelating compound

NASA Astrophysics Data System (ADS)

Szabó, László; Herman, Krisztian; Leopold, Nicolae; Buzumurgă, Claudia; Chiş, Vasile

2011-06-01

The surface-enhanced Raman scattering (SERS) spectra of Eriochrome Black T (EBT) and its Cu(II), Fe(III), Mn(II) and Pb(II) complexes were recorded using a hydroxylamine reduced silver colloid. Molecular geometry optimization, molecular electrostatic potential (MEP) distribution and vibrational frequencies calculation were performed at B3LYP/6-31G(d) level of theory for the EBT molecule and its Cu(EBT), Fe(EBT) and Mn(EBT) metal complexes. Differentiation between EBT complexes of Cu(II), Fe(III), Mn(II) and Pb(II) is shown by the SERS spectral features of each complex.

Nitrosomonas communis strain YNSRA, an ammonia-oxidizing bacterium, isolated from the reed rhizoplane in an aquaponics plant.

PubMed

Tokuyama, Tatsuaki; Mine, Atsusi; Kamiyama, Kaoru; Yabe, Ryuichi; Satoh, Kazuo; Matsumoto, Hirotoshi; Takahashi, Reiji; Itonaga, Koji

2004-01-01

An ammonia-oxidizing bacterium (strain YNSRA) was isolated from the rhizoplane of the reed (Phragmites communis) used in an aquaponics plant which is a wastewater treatment plant. Strain YNSRA was identified as Nitrosomonas communis by taxonomic studies. The hydroxylamine-cytochrome c reductase (HCR) of strain YNSRA was found to have a higher activity (25.60 u/mg) than that of Nitrosomonas europaea ATCC25978T (8.94 u/mg). Ribulose-1,5-bisphosphate carboxylase (RubisCO) activity was detected at very low levels in strain YNSRA, whereas strain ATCC25978T had definite activity.

Iron deficiency chlorosis in plants as related to Fe sources in soil

NASA Astrophysics Data System (ADS)

Díaz, I.; Delgado, A.; de Santiago, A.; del Campillo, M. C.; Torrent, J.

2012-04-01

Iron deficiency chlorosis (IDC) is a relevant agricultural problem in many areas of the World where calcareous soils are dominant. Although this problem has been traditionally ascribed to the pH-buffering effect of soil carbonates, the content and type of Fe oxides in soil contribute to explain Fe uptake by plants and the incidence of this problem. During the last two decades, it has been demonstrated Fe extraction with oxalate, related to the content of poorly crystalline Fe oxides, was well-correlated with the chlorophyll content of plants and thus with the incidence of IDC. This reveals the contribution of poorly crystalline Fe oxides in soil to Fe availability to plants in calcareous soils, previously shown in microcosm experiments using ferrihydrite as Fe source in the growing media. In order to supply additional information about the contribution of Fe sources in soil to explain the incidence of IDC and to perform accurate methods to predict it, a set of experiments involving different methods to extract soil Fe and plant cultivation in pots to correlate amounts of extracted Fe with the chlorophyll content of plants (measured using the SPAD chlorophyll meter) were performed. The first experiment involved 21 soils and white lupin cultivation, sequential Fe extraction in soil to study Fe forms, and single extractions (DTPA, rapid oxalate and non-buffered hydroxylamine). After that, a set of experiments in pot involving growing of grapevine rootstocks, chickpea, and sunflower were performed, although in this case only single extractions in soil were done. The Fe fraction more closely related to chlorophyll content in plants (r = 0.5, p < 0.05) was the citrate + ascorbate (CA) extraction, which was the fraction that releases most of the Fe related to poorly crystalline Fe oxides, thus revealing the key role of these compounds in Fe supply to plants. Fe extracted with CA was more correlated with chlorophyll content in plants that oxalate extractable Fe, probably due to a more selective dissolution of poorly crystalline oxides by the former extractant. In general terms, the best correlation between extractable Fe and chlorophyll content in plants was observed with hydroxylamine, which explained from 21 to 72 % of the variance observed in chlorophyll content in plants, greater than the variance explained by the rapid oxalate (11 to 60 %, not always significant) or the classical active calcium carbonate content determination (6 to 56 %, not always significant). Extraction with DTPA provided the worse results, explaining from 18 to 36 % of the variance in chlorophyll content in plants. The good predictive value of the hydroxylamine extraction was explained by its correlation with Fe in poorly crystalline Fe oxides (estimated as CA-extractable Fe) and by its negative correlation with the active calcium carbonate content of soils.

Habitual Dietary Nitrate Intake in Highly Trained Athletes.

PubMed

Jonvik, Kristin L; Nyakayiru, Jean; van Dijk, Jan-Willem; Wardenaar, Floris C; van Loon, Luc J C; Verdijk, Lex B

2017-04-01

Although beetroot juice, as a nitrate carrier, is a popular ergogenic supplement among athletes, nitrate is consumed through the regular diet as well. We aimed to assess the habitual dietary nitrate intake and identify the main contributing food sources in a large group of highly trained athletes. Dutch highly trained athletes (226 women and 327 men) completed 2-4 web-based 24-hr dietary recalls and questionnaires within a 2- to 4-week period. The nitrate content of food products and food groups was determined systematically based on values found in regulatory reports and scientific literature. These were then used to calculate each athlete's dietary nitrate intake from the web-based recalls. The median[IQR] habitual nitrate intake was 106[75-170] mg/d (range 19-525 mg/d). Nitrate intake correlated with energy intake (ρ = 0.28, p < .001), and strongly correlated with vegetable intake (ρ = 0.78, p < .001). In accordance, most of the dietary nitrate was consumed through vegetables, potatoes and fruit, accounting for 74% of total nitrate intake, with lettuce and spinach contributing most. When corrected for energy intake, nitrate intake was substantially higher in female vs male athletes (12.8[9.2-20.0] vs 9.4[6.2-13.8] mg/MJ; p < .001). This difference was attributed to the higher vegetable intake in female vs male athletes (150[88-236] vs 114[61-183] g/d; p < .001). In conclusion, median daily intake of dietary nitrate in highly trained athletes was 106 mg, with large interindividual variation. Dietary nitrate intake was strongly associated with the intake of vegetables. Increasing the intake of nitrate-rich vegetables in the diet might serve as an alternative strategy for nitrate supplementation.

In low transpiring conditions, uncoupling the BnNrt2.1 and BnNrt1.1 NO3- transporters by glutamate treatment reveals the essential role of BnNRT2.1 for nitrate uptake and the nitrate-signaling cascade during growth

PubMed Central

Leblanc, Antonin; Segura, Raphaël; Deleu, Carole; Le Deunff, Erwan

2013-01-01

In plants, the nitrate transporters, NRT1.1 and NRT2.1, are mainly responsible for nitrate uptake. Intriguingly, both nitrate transporters are located in a complementary manner in different cells layers of the mature root suggesting that their coordination should occur during nitrate uptake and plant growth. This hypothesis was examined on 5-d-old rape seedlings grown on agar medium supplemented with 1 or 5mM nitrate. Seedlings were treated with increasing potassium glutamate concentrations in order to uncouple the two nitrate transporters by inhibiting BnNRT2.1 expression and activity specifically. In both nitrate treatments, increasing the glutamate concentrations from 0.5 to 10mM induced a reduction in 15NO3- uptake and an inhibition of N assimilation. The decrease in 15NO3- uptake was caused by downregulation of BnNRT2.1 expression but surprisingly it was not compensated by the upregulation of BnNRT1.1. This created an unprecedented physiological situation where the effects of the nitrate signal on shoot growth were solely modulated by nitrate absorption. In these conditions, the osmotic water flow for volumetric shoot growth was mainly dependent on active nitrate transport and nitrate signaling. This behavior was confirmed by the allometric relationships found between changes in the root length with 15N and water accumulation in the shoot. These findings demonstrate that the BnNRT2.1 transporter is essential for nitrate uptake and growth, and renew the question of the respective roles of the NRT2.1 and NRT1.1 transporters in nitrate uptake and sensing at the whole plant level. PMID:23299418

Distinguishing summertime atmospheric production of nitrate across the East Antarctic Ice Sheet

NASA Astrophysics Data System (ADS)

Shi, G.; Buffen, A. M.; Ma, H.; Hu, Z.; Sun, B.; Li, C.; Yu, J.; Ma, T.; An, C.; Jiang, S.; Li, Y.; Hastings, M. G.

2018-06-01

Surface snow and atmospheric samples collected along a traverse from the coast to the ice sheet summit (Dome A) are used to investigate summertime atmospheric production of nitrate (NO3-) across East Antarctica. The strong relationship observed between δ15N and δ18O of nitrate in the surface snow suggests a large (lesser) extent of nitrate photolysis in the interior (coastal) region. A linear correlation between the oxygen isotopes of nitrate (δ18O and Δ17O) indicates mixing of various oxidants that react with NOx (NOx = NO + NO2) to produce atmospheric nitrate. On the plateau, the isotopes of snow nitrate are best explained by local reoxidation chemistry of NOx, possibly occurring in both condensed and gas phases. Nitrate photolysis results in redistribution of snow nitrate, and the plateau snow is a net exporter of nitrate and its precursors. Our results suggest that while snow-sourced NOx from the plateau due to photolysis is a significant input to the nitrate budget in coastal snow (up to ∼35%), tropospheric transport from mid-low latitudes dominates (∼65%) coastal snow nitrate. The linear relationship of δ18O vs. Δ17O of the snow nitrate suggests a predominant role of hydroxyl radical (OH) and ozone (O3) in nitrate production, although a high Δ17O(O3) is required to explain the observations. Across Antarctica the oxygen isotope composition of OH appears to be dominated by exchange with water vapor, despite the very dry environment. One of the largest uncertainties in quantifying nitrate production pathways is the limited knowledge of atmospheric oxidant isotopic compositions.

Nitrate Utilization by the Diatom Skeletonema costatum

PubMed Central

Serra, Juan L.; Llama, Maria J.; Cadenas, Eduardo

1978-01-01

Nitrate uptake has been studied in nitrogen-deficient cells of the marine diatom Skeletonema costatum. When these cells are incubated in the presence of nitrate, this ion is quickly taken up from the medium, and nitrite is excreted by the cells. Nitrite is excreted following classical saturation kinetics, its rate being independent of nitrate concentration in the incubation medium for nitrate concentration values higher than 3 micromolar. Nitrate uptake shows mixed-transfer kinetics, which can be attributed to the simultaneous contributions of mediated and diffusion transfer. Cycloheximide and p-hydroxymercuribenzoate inhibit the carrier-mediated contribution to nitrate uptake, without affecting the diffusion component. When cells are preincubated with nitrate, the net nitrogen uptake is increased. PMID:16660652

Mechanisms of nitrate capture in biochar: Are they related to biochar properties, post-treatment and soil environment?

NASA Astrophysics Data System (ADS)

Cimo, Giulia; Haller, Andreas; Spokas, Kurt; Novak, Jeff; Ippolito, Jim; Löhnertz, Otmar; Kammann, Claudia

2017-04-01

Biochar use in soils is assumed to increase soil fertility and the efficiency of nutrient use, particularly nitrogen. It was demonstrated recently that biochar is able to capture considerable amounts of the mobile anion nitrate which was observed in co-composted as well as field aged biochar1,2. Moreover the nitrate was not sufficiently extractable with standard methods from biochar particles; extractions had to be repeated to effectively remove the nitrate1. Subsequently the co-composted nitrate-enriched biochar stimulated plant growth due to N supply to the plants2. However, in a field study in sandy soil in Germany, a different biochar also captured nitrate, increasing the topsoil nitrate concentration and likely reducing nitrate leaching to subsoils1. This was particularly seen after a dry year in the re-picked and analysed particles. However, in the field experiment this aged, nitrate-enriched biochar did not improve crop yields3. To better understand the way biochar interacts with nitrate we undertook several laboratory experiments with 13 well characterized biochars produced from cypress, pine and grapewood at 350, 500, 700 and 900 °C including one Kon-Tiki produced grapewood biochar (600-700°C). Our results showed that (1) pure, pristine (not post-treated) biochar captured more nitrate when they were air-moist and not totally dry; that (2) letting biochar particles dry in nitrate solution forces more nitrate into biochar particles than incubating them in the solution, but (3) that shaking during drying nevertheless caused a higher nitrate uptake into biochar particles; that(4) the counter ion K+ in nitrate solution was more effective than Na+ for N-loading of biochar; (5)that drying a soil-biochar mix in nitrate solution produced a higher nitrate loading of the mixture (i.e. the biochar) than drying both components separately in the same solution; (6)that a higher biochar production temperature caused higher nitrate capture up to 700-900°C. Furthermore we found (7)that this captured nitrate was well protected against leaching, (8)that repeated drying-wetting cycles increased nitrate capture, with the amount protected against leaching remaining more or less constant; and (9) that an organic "coating" (or application of the nitrate in an organic solution, here: black tea) increased biochars' capability of nitrate capture. Our results thus underline that the phenomenon of nitrate capture is not purely due to ionic mechanisms but may partly rely on physical interactions and the pore structure of the biochar. Acknowledgement: JC acknowledges funding by the COST action TD1107 (short term scientific mission), CK acknowledges the financial support of DFG grant no. Ka3442/1-1 and of the HMWK Hessia funded OptiChar4EcoVin project. 1-Haider, G., Steffens, D., Müller, C. & Kammann, C. I. Standard extraction methods may underestimate nitrate stocks captured by field aged biochar. J. Environ. Qual. 45, 1196-1204 (2016). 2-Kammann, C. I. et al. Plant growth improvement mediated by nitrate capture in co-composted biochar. Scientific Reports 5, doi: 10.1038/srep11080 (2015). 3-Haider, G., Steffens, D., Moser, G., Müller, C. & Kammann, C. I. Biochar reduced nitrate leaching and improved soil moisture content without yield improvements in a four-year field study. Agri. Ecosys. Environ. 237, 80-94 (2017).

The preservation of long-range transported nitrate in snow at Summit, Greenland (Invited)

NASA Astrophysics Data System (ADS)

Hastings, M. G.

2013-12-01

Nitrate is one of the major anions found in polar and alpine snow, both today and in the past. Deposition of nitrate to snow surfaces results from reactions of nitrogen oxides (NOx) with oxidants in the atmosphere, resulting in the production of HNO3 that is incorporated into precipitation or reacts on the surface of particles. Several factors motivate studying nitrate concentration in ice cores including reconstructing past levels of NOx, tropospheric oxidant concentrations and natural variability in NOx sources. The link between the atmospheric concentration of NOx and nitrate concentration in ice core records is problematic because post-depositional processing, such as photolysis and evaporation, can impact the concentration of nitrate in snow. Recent work has shown that the isotopic ratios of nitrate (15N/14N, 18O/16O, 17O/16O) can be a powerful tool for tracing post-depositional loss of nitrate from surface snow. The isotopic composition of nitrate has been shown to contain information about the source of the nitrate (i.e, NOx sources) and the oxidation processes that convert NOx to nitrate in the atmosphere prior to deposition. Results from a number of studies at Summit, Greenland reveal limited loss of nitrate from surface snow during highly photoactive periods, and the oxygen isotopic signatures in snow nitrate appear to be representative of atmospheric deposition of nitrate from outside of Summit. Higher than expected oxygen isotope ratios (18O/16O, 17O/16O) found in Summit summertime nitrate were expected to be dependent upon local photochemistry in which nitrate in the snow is photolyzed to NOx that is then oxidized above the snow by BrO to reform nitrate (i.e., BrONO2). However, the oxygen isotopic composition of nitrate collected at high time resolution in surface snow does not show any link to local gas phase concentrations of a number of species, including BrO. Furthermore, the combination of nitrogen and oxygen isotope data reveals interesting insights into the contributions of nitrate sources to Summit. There are several important implications of this work including that nitrate at Summit appears to be largely preserved in surface snow during photoactive periods, and that nitrate in snow at Summit also appears to be representative of long-range transported nitrate/NOx. The surface snow work is further substantiated by relationships found between and among seasonally-resolved ice core measurements of the isotopic composition of nitrate, nitrate concentration and a suite of chemical and elemental tracers. The seasonality observed in 15N/14N ratios in an ice core representing accumulation since 1760 C.E. cannot be explained by diffusion or other processes occurring in the firn over time. A marked negative trend in 15N/14N since industrialization, parallels a nearly three-fold increase in nitrate concentration as well as pronounced increases in tracers such as excess lead and non-sea-salt sulfur. This, along with independent estimates of oil burning and transport studies, indicate that North American oil combustion is the primary driver of the modern negative trend in 15N/14N of nitrate. The high, positive 15N/14N ratios found in pre-industrial ice link to biomass burning based upon concentrations of black carbon and ammonium.

Low density lipoprotein receptor gene Ava II polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

PubMed Central

2011-01-01

Background Several common genetic polymorphisms in the low density lipoprotein receptor (LDL-R) gene have associated with modifications of serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels, but the results are not consistent in different populations. Bai Ku Yao is a special subgroup of the Yao minority in China. The present study was undertaken to detect the association of LDL-R gene Ava Ⅱ polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations. Methods A total of 1024 subjects of Bai Ku Yao and 792 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the LDL-R gene Ava Ⅱ polymorphism was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. Results The levels of serum TC, high density lipoprotein cholesterol (HDL-C), LDL-C, apolipoprotein (Apo) A1 and the ratio of ApoA1 to ApoB were lower in Bai Ku Yao than in Han (P < 0.01 for all). The frequency of A- and A+ alleles was 65.5% and 34.5% in Bai Ku Yao, and 80.7% and 19.3% in Han (P < 0.001); respectively. The frequency of A-A-, A-A+ and A+A+ genotypes was 42.6%, 45.9% and 11.5% in Bai Ku Yao, and 64.9%, 31.6% and 3.5% in Han (P < 0.001); respectively. There was also significant difference in the genotypic frequencies between males and females in Bai Ku Yao (P <0.05), and in the genotypic and allelic frequencies between normal LDL-C (≤ 3.20 mmol/L) and high LDL-C (>3.20 mmol/L) subgroups in Bai Ku Yao (P < 0.05 for each) and between males and females in Han (P < 0.05 for each). The levels of LDL-C in males and TC and HDL-C in females were different among the three genotypes (P < 0.05 for all) in Bai Ku Yao, whereas the levels of HDL-C in males and HDL-C and ApoA1 in females were different among the three genotypes (P < 0.05-0.001) in Han. The subjects with A+A+ genotype had higher serum LDL-C, TC, HDL-C or ApoA1 levels than the subjects with A-A+ and A-A- genotypes. Spearman rank correlation analysis revealed that the levels of LDL-C in Bai Ku Yao and HDL-C in Han were correlated with genotypes (P < 0.05 and P < 0.01; respectively). Conclusions The association of LDL-R gene Ava Ⅱ polymorphism and serum lipid levels is different between the Bai Ku Yao and Han populations. The discrepancy might partly result from different LDL-R gene Ava Ⅱ polymorphism or LDL-R gene-enviromental interactions. PMID:21345210

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions of this subpart are applicable to discharges resulting from the manufacture of ammonium nitrate...

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions of this subpart are applicable to discharges resulting from the manufacture of ammonium nitrate...

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions of this subpart are applicable to discharges resulting from the manufacture of ammonium nitrate...

40 CFR 418.40 - Applicability; description of the ammonium nitrate subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ammonium nitrate subcategory. 418.40 Section 418.40 Protection of Environment ENVIRONMENTAL PROTECTION... Ammonium Nitrate Subcategory § 418.40 Applicability; description of the ammonium nitrate subcategory. The provisions of this subpart are applicable to discharges resulting from the manufacture of ammonium nitrate...

Histological characteristics following a long-term nitrate-rich diet in miniature pigs with parotid atrophy

PubMed Central

Xia, Dengsheng; Qu, Xingmin; Tran, Simon D; Schmidt, Laura L; Qin, Lizheng; Zhang, Chunmei; Cui, Xiuyu; Deng, Dajun; Wang, Songlin

2015-01-01

The aim of this study was to investigate the histological characteristics following a 2-year nitrate-rich diet in miniature pigs with parotid atrophy. Using averages collected data from three time points at 6, 12, and 24 months following the induction of parotid gland atrophy, salivary nitrate levels of the nitrate-diet parotid-atrophied group (17.3±3.9 ng/µl) were close to those of the control group (19.6±5.1 ng/µl). Compared to the control group, the nitrate-diet group had significantly higher nitrate levels in blood (P < 0.05) and urine (P < 0.001). Histological and electron microscopy analyses showed no abnormalities in the organs of experimental or control animals. No significant differences on apoptosis rate were found in liver and kidney tissues between the standard- and nitrate-diet groups. Therefore, dietary nitrate supplementation could restore salivary nitrate levels. High-dose nitrate loading for 2 years had no observed systemic toxicity in miniature pigs with parotid atrophy. PMID:26261499