One-Pot Enzymatic Synthesis of D-Arylalanines Using Phenylalanine Ammonia Lyase and L-Amino Acid Deaminase.

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Zhu, Longbao; Feng, Guoqiang; Ge, Fei; Song, Ping; Wang, Taotao; Liu, Yi; Tao, Yugui; Zhou, Zhemin

2018-06-08

The phenylalanine ammonia-lyase (AvPAL) from Anabaena variabilis catalyzes the amination of substituent trans-cinnamic acid (t-CA) to produce racemic D,L-enantiomer arylalanine mixture owing to its low stereoselectivity. To produce high optically pure D-arylalanine, a modified AvPAL with high D-selectivity is expected. Based on the analyses of catalytic mechanism and structure, the Asn347 residue in the active site was proposed to control stereoselectivity. Therefore, Asn347 was mutated to construct mutant AvPAL-N347A, the stereoselectivity of AvPAL-N347A for D-enantiomer arylalanine was 2.3-fold higher than that of wild-type AvPAL (WtPAL). Furthermore, the residual L-enantiomer product in reaction solution could be converted into the D-enantiomer product through stereoselective oxidation by PmLAAD and nonselective reduction by reducing agent NH 3 BH 3 . At optimal conditions, the conversion rate of t-CA and optical purity (enantiomeric excess (ee D )) of D-phenylalanine reached 82% and exceeded 99%, respectively. The two enzymes displayed activity toward a broad range of substrate and could be used to efficiently synthesize D-arylalanine with different groups on the phenyl ring. Among these D-arylalanines, the yield of m-nitro-D-phenylalanine was highest and reached 96%, and the ee D exceeded 99%. This one-pot synthesis using AvPAL and PmLAAD has prospects for industrial application.

Retroviral-mediated gene transfer and expression of human phenylalanine hydroxylase in primary mouse hepatocytes

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Peng, H.; Armentano, D.; Mackenzie-Graham, L.; Shen, R.F.; Darlington, G.; Ledley, F.D.; Woo, S.L.C. (Baylor College of Medicine, Houston, TX (USA))

1988-11-01

Genetic therapy for phenylketonuria (severe phenylalanine hydroxylase deficiency) may require introduction of a normal phenylalanine hydroxylase gene into hepatic cells of patients. The authors report development of a recombinant retrovirus based on the N2 vector for gene transfer and expression of human phenylalanine hydroxylase cDNA in primary mouse hepatocytes. This construct contains an internal promoter of the human {alpha}{sub 1}-antitrypsin gene driving transcription of the phenylalanine hydroxylase cDNA. Primary mouse hepatocytes were isolated from newborn mice, infected with the recombinant virus, and selected for expression of the neomycin-resistance gene. Hepatocytes transformed with the recombinant virus contained high levels of human phenylalanine hydroxylase mRNA transcripts originating from the retroviral and internal promoters. These results demonstrate that the transcriptional regulatory elements of the {alpha}{sub 1} antitrypsin gene retain their tissue-specific function in the recombinant provirus and establish a method for efficient transfer and high-level expression of human phenylalanine hydroxylase in primary hepatocytes.

Retroviral-mediated gene transfer and expression of human phenylalanine hydroxylase in primary mouse hepatocytes

International Nuclear Information System (INIS)

Peng, H.; Armentano, D.; Mackenzie-Graham, L.; Shen, R.F.; Darlington, G.; Ledley, F.D.; Woo, S.L.C.

1988-01-01

Genetic therapy for phenylketonuria (severe phenylalanine hydroxylase deficiency) may require introduction of a normal phenylalanine hydroxylase gene into hepatic cells of patients. The authors report development of a recombinant retrovirus based on the N2 vector for gene transfer and expression of human phenylalanine hydroxylase cDNA in primary mouse hepatocytes. This construct contains an internal promoter of the human α 1 -antitrypsin gene driving transcription of the phenylalanine hydroxylase cDNA. Primary mouse hepatocytes were isolated from newborn mice, infected with the recombinant virus, and selected for expression of the neomycin-resistance gene. Hepatocytes transformed with the recombinant virus contained high levels of human phenylalanine hydroxylase mRNA transcripts originating from the retroviral and internal promoters. These results demonstrate that the transcriptional regulatory elements of the α 1 antitrypsin gene retain their tissue-specific function in the recombinant provirus and establish a method for efficient transfer and high-level expression of human phenylalanine hydroxylase in primary hepatocytes

Biochemical Evaluation of Phenylalanine Ammonia Lyase from Endemic Plant Cyathobasis fruticulosa (Bunge Aellen. for the Dietary Treatment of Phenylketonuria

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Seda Şirin

2016-01-01

Full Text Available Enzyme substitution therapy with the phenylalanine ammonia lyase (PAL is a new approach to the treatment of patients with phenylketonuria (PKU. This enzyme is responsible for the conversion of phenylalanine to trans-cinnamic acid. We assessed the PAL enzyme of the endemic plant Cyathobasis fruticulosa (Bunge Aellen. for its possible role in the dietary treatment of PKU. The enzyme was found to have a high activity of (64.9±0.1 U/mg, with the optimum pH, temperature and buffer (Tris–HCl and L-phenylalanine concentration levels of pH=8.8, 37 °C and 100 mM, respectively. Optimum enzyme activity was achieved at pH=4.0 and 7.5, corresponding to pH levels of gastric and intestinal juice, and NaCl concentration of 200 mM. The purifi cation of the enzyme by 1.87-fold yielded an activity of 98.6 U/mg. PAL activities determined by HPLC analyses before and after purification were similar. Two protein bands, one at 70 and the other at 23 kDa, were determined by Western blot analysis of the enzyme. This enzyme is a potential candidate for serial production of dietary food and biotechnological products.

Genomic Characterization of Phenylalanine Ammonia Lyase Gene in Buckwheat.

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Karthikeyan Thiyagarajan

Full Text Available Phenylalanine Ammonia Lyase (PAL gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum. The identified SNPs in F. tataricum didn't result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value.

Optimization of oligomeric enzyme activity in ionic liquids using Rhodotorula glutinis yeast phenylalanine ammonia lyase.

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Barron, Christiaan C; Sponagle, Brandon J D; Arivalagan, Pugazhendhi; D'Cunha, Godwin B

2017-01-01

Phenylalanine ammonia lyase (E.C.4.3.1.24, PAL) activity of Rhodotorula glutinis yeast has been demonstrated in four commonly used ionic liquids. PAL forward reaction was carried out in 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO 4 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) and 1-butyl-3-methylimidazolium lactate ([BMIM][lactate]). Our experiments have revealed that PAL is catalytically active in ionic liquids and the enzyme activity in ([BMIM][PF 6 ]) is comparable to that obtained in aqueous buffer medium. Different conditions were optimized for maximal PAL forward activity including time of incubation (30.0min) L -phenylalanine substrate concentration (30.0mM), nature of buffer (50.0mM Tris-HCl), pH (9.0), temperature (37°C), and speed of agitation (100 rev min -1 ). Under these optimized conditions, about 83% conversion of substrate to product was obtained for the PAL forward reaction that was determined using UV spectroscopy at 290nm. PAL reverse reaction in ([BMIM][PF 6 ]) was determined spectrophotometrically at 520nm; and about 59% substrate conversion was obtained. This data provides further knowledge in enzyme biocatalysis in non-aqueous media, and may be of importance when studying the function of other oligomeric/multimeric proteins and enzymes in ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular Cloning and Sequence Analysis of a Phenylalanine Ammonia-Lyase Gene from Dendrobium

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Cai, Yongping; Lin, Yi

2013-01-01

In this study, a phenylalanine ammonia-lyase (PAL) gene was cloned from Dendrobium candidum using homology cloning and RACE. The full-length sequence and catalytic active sites that appear in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum are also found: PAL cDNA of D. candidum (designated Dc-PAL1, GenBank No. JQ765748) has 2,458 bps and contains a complete open reading frame (ORF) of 2,142 bps, which encodes 713 amino acid residues. The amino acid sequence of DcPAL1 has more than 80% sequence identity with the PAL genes of other plants, as indicated by multiple alignments. The dominant sites and catalytic active sites, which are similar to that showing in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum, are also found in DcPAL1. Phylogenetic tree analysis revealed that DcPAL is more closely related to PALs from orchidaceae plants than to those of other plants. The differential expression patterns of PAL in protocorm-like body, leaf, stem, and root, suggest that the PAL gene performs multiple physiological functions in Dendrobium candidum. PMID:23638048

Structural And Biochemical Characterization of the Therapeutic A. Variabilis Phenylalanine Ammonia Lyase

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Wang, L.; Gamez, A.; Archer, H.; Abola, E.E.; Sarkissian, C.N.; Fitzpatrick, P.; Wendt, D.; Zhang, Y.; Vellard, M.; Bliesath, J.; Bell, S.; Lemont, J.; Scriver, C.R.; Stevens, R.C.

2009-05-26

We have recently observed promising success in a mouse model for treating the metabolic disorder phenylketonuria with phenylalanine ammonia lyase (PAL) from Rhodosporidium toruloides and Anabaena variabilis. Both molecules, however, required further optimization in order to overcome problems with protease susceptibility, thermal stability, and aggregation. Previously, we optimized PAL from R. toruloides, and in this case we reduced aggregation of the A. variabilis PAL by mutating two surface cysteine residues (C503 and C565) to serines. Additionally, we report the structural and biochemical characterization of the A. variabilis PAL C503S/C565S double mutant and carefully compare this molecule with the R. toruloides engineered PAL molecule. Unlike previously published PAL structures, significant electron density is observed for the two active-site loops in the A. variabilis C503S/C565S double mutant, yielding a complete view of the active site. Docking studies and N-hydroxysuccinimide-biotin binding studies support a proposed mechanism in which the amino group of the phenylalanine substrate is attacked directly by the 4-methylidene-imidazole-5-one prosthetic group. We propose a helix-to-loop conformational switch in the helices flanking the inner active-site loop that regulates accessibility of the active site. Differences in loop stability among PAL homologs may explain the observed variation in enzyme efficiency, despite the highly conserved structure of the active site. A. variabilis C503S/C565S PAL is shown to be both more thermally stable and more resistant to proteolytic cleavage than R. toruloides PAL. Additional increases in thermal stability and protease resistance upon ligand binding may be due to enhanced interactions among the residues of the active site, possibly locking the active-site structure in place and stabilizing the tetramer. Examination of the A. variabilis C503S/C565S PAL structure, combined with analysis of its physical properties, provides

Suppressed phenylalanine ammonia-lyase activity after heat shock in transgenic Nicotiana plumbaginifolia containing an Arabidopsis HSP18.2-parsley PAL2 chimera gene.

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Moriwaki, M; Yamakawa, T; Washino, T; Kodama, T; Igarashi, Y

1999-01-01

The activity of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) after heat shock (HS) in leaves and buds of transgenic Nicotiana plumbaginifolia containing an Arabidopsis HSP18.2 promoter-parsley phenylalanine ammonia-lyase 2 (HSP18.2-PAL2) chimera gene was examined. Immediately after HS treatment at 44 degrees C for 5 h, the PAL activity in both transgenic and normal (untransformed) plants was 35-38% lower than that before HS. At normal temperature (25-26 degrees C), the PAL activity recovered within 5 h of ending the HS treatment in normal plants, but not until 12-24 h in transgenic plants containing the HSP18.2-PAL2 gene. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the presence of parsley PAL2 mRNA in transgenic plants, which remained for 8-12 h following 5-h HS at 44 degrees C; the mRNA was not observed before HS. The content of chlorogenic acid (CGA; 3-caffeoylquinic acid) decreased drastically 8-12 h after HS in transgenic plants, but only slightly in normal plants. Thus, the decrease in PAL activity accompanied by expression of the parsley PAL2 gene after HS treatment corresponded to the decrease in CGA synthesis. These results might be attributed to post-transcriptional degradation of endogenous PAL mRNA triggered by transcription of the transgene.

Stabilization of Phenylalanine Ammonia Lyase from Rhodotorula glutinis by Encapsulation in Polyethyleneimine-Mediated Biomimetic Silica.

Science.gov (United States)

Cui, Jiandong; Liang, Longhao; Han, Cong; Lin Liu, Rong

2015-06-01

Phenylalanine ammonia lyase (PAL) from Rhodotorula glutinis was encapsulated within polyethyleneimine-mediated biomimetic silica. The main factors in the preparation of biomimetic silica were optimized by response surface methodology (RSM). Compared to free PAL (about 2 U), the encapsulated PAL retained more than 43 % of their initial activity after 1 h of incubation time at 60 °C, whereas free PAL lost most of activity in the same conditions. It was clearly indicated that the thermal stability of PAL was improved by encapsulation. Moreover, the encapsulated PAL exhibited the excellent stability of the enzyme against denaturants and storage stability, and pH stability was improved by encapsulation. Operational stability of 7 reaction cycles showed that the encapsulated PAL was stable. Nevertheless, the K m value of encapsulated PAL in biomimetic silica was higher than that of the free PAL due to lower total surface area and increased mass transfer resistance.

Isolation and Functional Characterization of a Phenylalanine Ammonia-Lyase Gene (SsPAL1 from Coleus (Solenostemon scutellarioides (L. Codd

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Qinlong Zhu

2015-09-01

Full Text Available Phenylalanine ammonia-lyase (PAL is the first enzyme involved in the phenylpropanoid pathway and plays important roles in the secondary metabolisms, development and defense of plants. To study the molecular function of PAL in anthocyanin synthesis of Coleus (Solenostemon scutellarioides (L. Codd, a Coleus PAL gene designated as SsPAL1 was cloned and characterized using a degenerate oligonucleotide primer PCR and RACE method. The full-length SsPAL1 was 2450 bp in size and consisted of one intron and two exons encoding a polypeptide of 711 amino acids. The deduced SsPAL1 protein showed high identities and structural similarities with other functional plant PAL proteins. A series of putative cis-acting elements involved in transcriptional regulation, light and stress responsiveness were found in the upstream regulatory sequence of SsPAL1. Transcription pattern analysis indicated that SsPAL1 was constitutively expressed in all tissues examined and was enhanced by light and different abiotic factors. The recombinant SsPAL1 protein exhibited high PAL activity, at optimal conditions of 60 °C and pH 8.2. Although the levels of total PAL activity and total anthocyanin concentration have a similar variation trend in different Coleus cultivars, there was no significant correlation between them (r = 0.7529, p > 0.1, suggesting that PAL was not the rate-limiting enzyme for the downstream anthocyanin biosynthetic branch in Coleus. This study enables us to further understand the role of SsPAL1 in the phenylpropanoid (flavonoids, anthocyanins biosynthesis in Coleus at the molecular level.

Molecular cloning and sequence analysis of a phenylalanine ammonia-lyase gene from dendrobium.

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Qing Jin

Full Text Available In this study, a phenylalanine ammonia-lyase (PAL gene was cloned from Dendrobium candidum using homology cloning and RACE. The full-length sequence and catalytic active sites that appear in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum are also found: PAL cDNA of D. candidum (designated Dc-PAL1, GenBank No. JQ765748 has 2,458 bps and contains a complete open reading frame (ORF of 2,142 bps, which encodes 713 amino acid residues. The amino acid sequence of DcPAL1 has more than 80% sequence identity with the PAL genes of other plants, as indicated by multiple alignments. The dominant sites and catalytic active sites, which are similar to that showing in PAL proteins of Arabidopsis thaliana and Nicotiana tabacum, are also found in DcPAL1. Phylogenetic tree analysis revealed that DcPAL is more closely related to PALs from orchidaceae plants than to those of other plants. The differential expression patterns of PAL in protocorm-like body, leaf, stem, and root, suggest that the PAL gene performs multiple physiological functions in Dendrobium candidum.

Molecular cloning, characterization and expression of phenylalanine ...

African Journals Online (AJOL)

A full-length cDNA and genomic DNA of phenylalanine ammonia-lyase gene, which catalyzes the first step in the flavonoid biosynthetic pathway, were isolated from Ginkgo biloba for the first time (designated as GbPAL, GenBank Accession No. EU071050). The cDNA and genomic DNA sequences of GbPAL were the same, ...

Structure and characterization of a cDNA clone for phenylalanine ammonia-lyase from cut-injured roots of sweet potato

International Nuclear Information System (INIS)

Tanaka, Yoshiyuki; Matsuoka, Makoto; Yamanoto, Naoki; Ohashi, Yuko; Kano-Murakami, Yuriko; Ozeki, Yoshihiro

1989-01-01

A cDNA clone for phenylalanine ammonia-lyase (PAL) induced in wounded sweet potato (Ipomoea batatas Lam.) root was obtained by immunoscreening a cDNA library. The protein produced in Escherichia coli cells containing the plasmid pPAL02 was indistinguishable from sweet potato PAL as judged by Ouchterlony double diffusion assays. The M r of its subunit was 77,000. The cells converted [ 14 C]-L-phenylalanine into [ 14 C]-t-cinnamic acid and PAL activity was detected in the homogenate of the cells. The activity was dependent on the presence of the pPAL02 plasmid DNA. The nucleotide sequence of the cDNA contained a 2,121-base pair (bp) open-reading frame capable of coding for a polypeptide with 707 amino acids (M r 77,137), a 22-bp 5'-noncoding region and a 207-bp 3'-noncoding region. The results suggest that the insert DNA fully encoded the amino acid sequence for sweet potato PAL that is induced by wounding. Comparison of the deduced amino acid sequence with that of a PAL cDNA fragment from Phaseolus vulgaris revealed 78.9% homology. The sequence from amino acid residues 258 to 494 was highly conserved, showing 90.7% homology

Control of phenylalanine ammonia-lyase gene promoters from pea by UV radiation

International Nuclear Information System (INIS)

Pluskota, W.E.; Michalczyk, D.J.; Gorecki, R.J.

2005-01-01

The gene fusion system was used to study UV light-control of PS PAL1 and PS PAL2 genes encoding phenylalanine ammonia-lyase of pea. The induction of pea PAL promoters was analysed in transgenic tobacco plants. Binary plasmids (derivatives of pBI101.2 vector) containing 5' regulatory fragments of PS PAL1 and PS PAL2 linked to reporter genes (GUS, LUC) were constructed. The analyses were performed with the use of single constructs (containing one variant of PS PAL promoter and one reporter gene) and dual constructs (containing both PS PAL1 and PS PAL2 promoters connected with different reporter genes). The use of dual constructs enabled the evaluation of both PS PAL promoters activity in the same plant. The analyses of in vitro grown plants have shown that both PAL promoters are strongly induced in leaves subjected to UV radiation. In some cases, the UV-stimulated expression exceeded the exposed areas. This phenomenon was observed more often in the leaves of plants containing the PS PAL1::GUS than PS PAL2::GUS construct. Removal of boxes 2, 4, 5 from PS PAL1 promoter and deletion of its 5' end region (-339 to -1394) decreases the level of gene expression but does not eliminate its responsiveness to UV

Ammonia lyases and aminomutases as biocatalysts for the synthesis of α-amino and β-amino acids.

Science.gov (United States)

Turner, Nicholas J

2011-04-01

Ammonia lyases catalyse the reversible addition of ammonia to cinnamic acid (1: R=H) and p-hydroxycinnamic (1: R=OH) to generate L-phenylalanine (2: R=H) and L-tyrosine (2: R=OH) respectively (Figure 1a). Both phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) are widely distributed in plants, fungi and prokaryotes. Recently there has been interest in the use of these enzymes for the synthesis of a broader range of L-arylalanines. Aminomutases catalyse a related reaction, namely the interconversion of α-amino acids to β-amino acids (Figure 1b). In the case of L-phenylalanine, this reaction is catalysed by phenylalanine aminomutase (PAM) and proceeds stereospecifically via the intermediate cinnamic acid to generate β-Phe 3. Ammonia lyases and aminomutases are related in sequence and structure and share the same active site cofactor 4-methylideneimidazole-5-one (MIO). There is currently interest in the possibility of using these biocatalysts to prepare a wide range of enantiomerically pure l-configured α-amino and β-amino acids. Recent reviews have focused on the mechanism of these MIO containing enzymes. The aim of this review is to review recent progress in the application of ammonia lyase and aminomutase enzymes to prepare enantiomerically pure α-amino and β-amino acids. Copyright © 2010 Elsevier Ltd. All rights reserved.

Bacterial production of site specific {sup 13}C labeled phenylalanine and methodology for high level incorporation into bacterially expressed recombinant proteins

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Ramaraju, Bhargavi; McFeeters, Hana; Vogler, Bernhard; McFeeters, Robert L., E-mail: robert.mcfeeters@uah.edu [University of Alabama in Huntsville, Department of Chemistry (United States)

2017-01-15

Nuclear magnetic resonance spectroscopy studies of ever larger systems have benefited from many different forms of isotope labeling, in particular, site specific isotopic labeling. Site specific {sup 13}C labeling of methyl groups has become an established means of probing systems not amenable to traditional methodology. However useful, methyl reporter sites can be limited in number and/or location. Therefore, new complementary site specific isotope labeling strategies are valuable. Aromatic amino acids make excellent probes since they are often found at important interaction interfaces and play significant structural roles. Aromatic side chains have many of the same advantages as methyl containing amino acids including distinct {sup 13}C chemical shifts and multiple magnetically equivalent {sup 1}H positions. Herein we report economical bacterial production and one-step purification of phenylalanine with {sup 13}C incorporation at the Cα, Cγ and Cε positions, resulting in two isolated {sup 1}H-{sup 13}C spin systems. We also present methodology to maximize incorporation of phenylalanine into recombinantly overexpressed proteins in bacteria and demonstrate compatibility with ILV-methyl labeling. Inexpensive, site specific isotope labeled phenylalanine adds another dimension to biomolecular NMR, opening new avenues of study.

Cadmium-induced changes in pigments, total phenolics, and phenylalanine ammonia-lyase activity in fronds of Azolla imbricata.

Science.gov (United States)

Dai, Ling-Peng; Xiong, Zhi-Ting; Huang, Yu; Li, Min-Jing

2006-10-01

This study was designed to examine the effects of cadmium on several color-related parameters (including chlorophyll, carotenoid, and anthocyanin), total phenolics, and phenylalanine ammonia-lyase (PAL) activity in an aquatic fern species Azolla imbricate (A. imbricata). Cd accumulation and effects in the fronds were closely related with Cd concentration in the growth medium. The fronds under 0.5 mg/L Cd treatment turned red on the 3rd day, and this color change also appeared under 0.05 and 0.1 mg/L Cd treatment on the 5th day. Correlated with the color change, the contents of chlorophyll and carotenoid in the fronds significantly decreased in the presence of high Cd concentrations, while the anthocyanin content increased during the experiment. Significant increase in total phenolics content and PAL activity were also detected during Cd treatment. The results suggested that the Cd-induced change in color of fronds might be due to the decrease in chlorophyll and carotenoid and the increase in anthocyanin. Anthocyanin, total phenolics and their biosynthesis-related PAL might play a role in detoxification of Cd in A. imbricata.

Hydrogen Peroxide Treatment and the Phenylpropanoid Pathway Precursors Feeding Improve Phenolics and Antioxidant Capacity of Quinoa Sprouts via an Induction of L-Tyrosine and L-Phenylalanine Ammonia-Lyases Activities

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Michał Świeca

2016-01-01

Full Text Available Hydrogen peroxide treatment and the phenylpropanoid pathway precursors feeding affected the antioxidant capacity of quinoa sprouts. Compared to the control, total phenolics content was significantly increased by treatment of control sprouts with 50 mM and 200 mM H2O2—an elevation of about 24% and 28%, respectively. The highest increase of flavonoids content was found for the sprouts treated with 200 mM H2O2 obtained from seeds fed with shikimic acid. All the studied modifications increased the antioxidant potential of sprouts (at least by 50% compared to control. The highest reducing power was found for the sprouts treated with 200 mM H2O2 obtained by phenylalanine feeding (5.03 mg TE/g DW and those obtained from the seeds fed with tyrosine (5.26 mg TE/g DW. The activities of L-tyrosine (TAL and L-phenylalanine (PAL ammonia-lyases were strongly affected by germination time as well as the applied modification of sprouting. On the 3rd day the highest PAL activity was determined for both untreated and induced with 50 mM H2O2 sprouts obtained by phenylalanine feeding. H2O2 induced TAL activity; the highest TAL activity was determined for 3-day-old sprouts induced with 200 mM H2O2 obtained from seeds fed with phenylalanine.

Genome-wide characterization of phenylalanine ammonia-lyase gene family in watermelon (Citrullus lanatus).

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Dong, Chun-Juan; Shang, Qing-Mao

2013-07-01

Phenylalanine ammonia-lyase (PAL), the first enzyme in the phenylpropanoid pathway, plays a critical role in plant growth, development, and adaptation. PAL enzymes are encoded by a gene family in plants. Here, we report a genome-wide search for PAL genes in watermelon. A total of 12 PAL genes, designated ClPAL1-12, are identified . Nine are arranged in tandem in two duplication blocks located on chromosomes 4 and 7, and the other three ClPAL genes are distributed as single copies on chromosomes 2, 3, and 8. Both the cDNA and protein sequences of ClPALs share an overall high identity with each other. A phylogenetic analysis places 11 of the ClPALs into a separate cucurbit subclade, whereas ClPAL2, which belongs to neither monocots nor dicots, may serve as an ancestral PAL in plants. In the cucurbit subclade, seven ClPALs form homologous pairs with their counterparts from cucumber. Expression profiling reveals that 11 of the ClPAL genes are expressed and show preferential expression in the stems and male and female flowers. Six of the 12 ClPALs are moderately or strongly expressed in the fruits, particularly in the pulp, suggesting the potential roles of PAL in the development of fruit color and flavor. A promoter motif analysis of the ClPAL genes implies redundant but distinctive cis-regulatory structures for stress responsiveness. Finally, duplication events during the evolution and expansion of the ClPAL gene family are discussed, and the relationships between the ClPAL genes and their cucumber orthologs are estimated.

Electromagnetic Field Effects on Production of Salicylic Acid and Phenylalanine ammonia lyase in Tobacco Infected with Potato Virus X (PVX

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amin radmard titkanlo

2018-02-01

Full Text Available Introduction: Potato virus x (PVX is one of the most devastating viruses in the fields of tobacco and no effective method to control the virus has been provided yet. Magnetism is known as one of the environmental stresses that can directly or indirectly affect the plants, especially plants under stress. The magnetic fields can have beneficial affects plants. Materials and Methods: In the present study to investigate the effects of electromagnetic fields on PVX control, an experiment based on completely randomized design with eleven treatments (10, 50 and 90 mT in a period of 60, 90 and 120 minutes on tobacco seedlings infected with the virus and two control, and the other one is free from analog infected with the virus in tobacco seedlings carried on six repeats.. After inoculation at the four-leaf stage and after 14 days, the amount of turbidity virus infection rate is calculated and then ensure equality of tobacco seedlings, where the electromagnetic device. 30 days after applying an electromagnetic field analysis of the results of ELISA test two samples were tested with antisera Chndhmsanh of PVX. The amount of salicylic acid and the enzyme phenylalanine ammonia in systemic acquired resistance and plant defense mechanisms are involved, the treatments were measured, for evaluation of HPLC as salicylic acid and phenylalanine ammonia-based assessment of trans-cinnamic acid was used. Results and Discussion: Statistical analysis ELISA test results revealed that there is a significant difference between treatments 0/05. So that the treatment was a no pollution treatment and 11 who were infected but had not been exposed to the electromagnetic field had a significant difference compared to other treatments, among the treatments that were exposed to the electromagnetic field treatment 8 (100 mT, 120 minutes showed the lowest OD in ELISA and later treatment 7 (50 mT and 60 minutes was the lowest OD, the two treatments were observed in less than two OD

Expression and enzymatic activity of phenylalanine ammonia-lyase and p-coumarate 3-hydroxylase in mango (Mangifera indica 'Ataulfo') during ripening.

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Palafox-Carlos, H; Contreras-Vergara, C A; Muhlia-Almazán, A; Islas-Osuna, M A; González-Aguilar, G A

2014-05-16

Phenylalanine ammonia lyase (PAL) and p-coumarate 3-hydroxylase (C3H) are key enzymes in the phenylpropanoid pathway. The relative expression of PAL and C3H was evaluated in mango fruit cultivar 'Ataulfo' in four ripening stages (RS1, RS2, RS3, and RS4) by quantitative polymerase chain reaction. In addition, enzyme activity of PAL and C3H was determined in mango fruits during ripening. The PAL levels were downregulated at the RS2 and RS3 stages, while C3H levels were upregulated in fruits only at RS3. The enzyme activity of PAL followed a pattern that was different from that of the PAL expression, thus suggesting regulation at several levels. For C3H, a regulation at the transcriptional level is suggested because a similar pattern was revealed by its activity and transcript level. In this study, the complexity of secondary metabolite biosynthesis regulation is emphasized because PAL and C3H enzymes are involved in the biosynthesis of several secondary metabolites that are active during all mango ripening stages.

Phenylalanine ammonia-lyase (pal) and peroxidase activity in brown rust infected tissues of pakistani wheat cultivars

International Nuclear Information System (INIS)

Riaz, A.; Tahir, M.I.

2014-01-01

Besides other factors resistance and susceptibility is the outcome of biochemical processes such as activities of defense-related enzymes. So in this study, Phenylalanine ammonia-lyase (PAL) and Peroxidase activity of resistant (Inqilab-91) and susceptible (Kirin-95) wheat cultivars were determined through spectrophotometer to address the biochemical aspect related to the disease after 8 hours, 24 hours, 48 hours and 72 hours of leaf rust inoculation. The results have shown that these enzymes were present in both the resistant and susceptible cultivars but the activity was more pronounced in the resistant one. The effect of PAL and peroxidase activity was also investigated among inoculated and uninoculated plants within the same cultivar. The activity of both PAL and peroxidase were more significant in inoculated ones. The results have shown that the after 72 hours of inoculation Inqilab-91 had more PAL activity i.e., 5.47 IU/ml/min than in Kirin-95 i.e., 2.08 IU/ml/min at 270 nm. While peroxidase activity in Inqilab-91 was 6.41 IU/ml/min and in Kirin-95, 3.66 IU/ml/min after 72 hours of inoculation, observed under 470 nm wavelength. Increase in one's activity increases the other enzyme's activity. The activity was more prominent after 72 hours of infection as pathogen had successfully established itself in the host plant tissue. The activities of these enzymes act as plants active defense mechanism against the attack of pathogen. (author)

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African Journals Online (AJOL)

amino acids analysis (Especially for the free amino acids), this formula was then analyzed for .... Methods: Skim milk hydrolysates were pre-. 1. pared by two enzymes: purified. Protease ...... recombinant phenylalanine ammonia lyase. Proc.

Highly Active and Specific Tyrosine Ammonia-Lyases from Diverse Origins Enable Enhanced Production of Aromatic Compounds in Bacteria and Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Jendresen, Christian Bille; Stahlhut, Steen Gustav; Li, Mingji

2015-01-01

Phenylalanine and tyrosine ammonia-lyases form cinnamic acid and p-coumaric acid, which are precursors of a wide range of aromatic compounds of biotechnological interest. Lack of highly active and specific tyrosine ammonia-lyases has previously been a limitation in metabolic engineering approaches...

Molecular and analysis of a phenylalanine ammonia-lyase gene (LrPAL2) from Lycoris radiata.

Science.gov (United States)

Jiang, Yumei; Xia, Bing; Liang, Lijian; Li, Xiaodan; Xu, Sheng; Peng, Feng; Wang, Ren

2013-03-01

Phenylalanine ammonia-lyase (PAL), the first enzyme of phenylpropanoid biosynthesis, participates in the biosynthesis of flavonoids, lignins, stilbenes and many other compounds. In this study, we cloned a 2,326 bp full-length PAL2 gene from Lycoris radiata by using degenerate oligonucleotide primer PCR (DOP-PCR) and the rapid amplification of cDNA ends method. The cDNA contains a 2,124 bp coding region encoding 707 amino acids. The LrPAL2 shares about 77.0 % nucleic acid identity and 83 % amino acid identity with LrPAL1. Furthermore, genome sequence analysis demonstrated that LrPAL2 gene contains one intron and two exons. The 5' flanking sequence of LrPAL2 was also cloned by self-formed adaptor PCR (SEFA-PCR), and a group of putative cis-acting elements such as TATA box, CAAT box, G box, TC-rich repeats, CGTCA motif and TCA-element were identified. The LrPAL2 was detected in all tissues examined, with high abundance in bulbs at leaf sprouting stage and in petals at blooming stage. Besides, LrPAL2 drastically responded to MJ, SNP and UV, moderately responded to GA and SA, and a little increased under wounding. Comparison of LrPAL2 expression and LrPAL1 expression demonstrated that LrPAL2 can be more significantly induced than LrPAL1 under the above treatments, and LrPAL2 transcripts accumulated prominently at blooming stage, especially in petals, while LrPAL1 transcripts did not accumulated significantly at blooming stage. All these results suggested that LrPAL2 might play distinct roles in different branches of the phenylpropanoid pathway.

Therapeutic implication of L-phenylalanine aggregation mechanism and its modulation by D-phenylalanine in phenylketonuria

Science.gov (United States)

Singh, Virender; Rai, Ratan Kumar; Arora, Ashish; Sinha, Neeraj; Thakur, Ashwani Kumar

2014-01-01

Self-assembly of phenylalanine is linked to amyloid formation toxicity in phenylketonuria disease. We are demonstrating that L-phenylalanine self-assembles to amyloid fibrils at varying experimental conditions and transforms to a gel state at saturated concentration. Biophysical methods including nuclear magnetic resonance, resistance by alpha-phenylglycine to fibril formation and preference of protected phenylalanine to self-assemble show that this behaviour of L-phenylalanine is governed mainly by hydrophobic interactions. Interestingly, D-phenylalanine arrests the fibre formation by L-phenylalanine and gives rise to flakes. These flakes do not propagate further and prevent fibre formation by L-phenylalanine. This suggests the use of D-phenylalanine as modulator of L-phenylalanine amyloid formation and may qualify as a therapeutic molecule in phenylketonuria. PMID:24464217

Cloning and Expression Analysis of Phenylalanine Ammonia-Lyase Gene in the Mycelium and Fruit Body of the Edible Mushroom Flammulina velutipes

Science.gov (United States)

Yun, Yeo Hong; Koo, Ja Sun

2015-01-01

Phenylalanine ammonia-lyase (PAL) gene is known to be expressed in plants, and is involved in the differentiation, growth and synthesis of secondary metabolites. However, its expression in fungi remains to be explored. To understand its expression in mushroom fungi, the PAL gene of the edible mushroom Flammulina velutipes (Fvpal) was cloned and characterized. The cloned Fvpal consists of 2,175 bp, coding for a polypeptide containing 724 amino acids and having 11 introns. The translated amino acid sequence of Fvpal shares a high identity (66%) with that of ectomycorrhizal fungus Tricholoma matsutake. Distinctively, the Fvpal expression in the mycelium was higher in minimal medium supplemented with L-tyrosine than with other aromatic amino acids. During cultivation of the mushroom on sawdust medium, Fvpal expression in the fruit body correspondingly increased as the mushroom grew. In the fruiting body, Fvpal was expressed more in the stipe than in the pileus. These results suggest that F. velutipes PAL activity differs in the different organs of the mushroom. Overall, this is first report to show that the PAL gene expression is associated with mushroom growth in fungi. PMID:26539050

Rhodotorulaglutinis phenylalanine/tyrosine ammonia lyase enzyme catalyzed synthesis of the methyl ester of para-hydroxycinnamic acid and its potential antibacterial activity

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Marybeth C MacDonald

2016-03-01

Full Text Available Biotransformation of L-tyrosine methyl ester (L-TM to the methyl ester of para- hydroxycinnamic acid (p-HCAM using Rhodotorula glutinis yeast phenylalanine/tyrosine ammonia lyase (PTAL; EC 4.3.1.26 enzyme was successfully demonstrated for the first time; progress of the reaction was followed by spectrophotometric determination at 315 nm. The following conditions were optimized for maximal formation of p-HCAM: pH (8.5, temperature (37 C, speed of agitation (50 rpm, enzyme concentration (0.080 µM, and substrate concentration (0.50 mM. Under these conditions, the yield of the reaction was ~15% in 1 h incubation period and ~63% after an overnight (~18 h incubation period. The product (p-HCAM of the reaction of PTAL with L-TM was confirmed using Nuclear Magnetic Resonance spectroscopy (NMR. Fourier Transform Infra-Red spectroscopy (FTIR was carried out to rule out potential hydrolysis of p-HCAM during overnight incubation. Potential antibacterial activity of p-HCAM was tested against several strains of Gram positive and Gram negative bacteria. This study describes a synthetically useful transformation, and could have future clinical and industrial applications.

Change in the Content of Salicylic Acid and in the Activities of Phenylalanine Ammonia-Lyase and Catalase in Wheat Seedling Roots Under the Effect of Azospirillum Lectins

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Alen'kina S.A.

2012-05-01

Full Text Available We investigated the time course of changes in the endogenous content of salicylic acid, the ratio between the acid's free and bound forms, and changes in the activities of phenylalanine ammonia-lyase and catalase in wheat seedling roots under the effect of the lectins of two strains of the associative nitrogen-fixing bacterium Azospirillum: A. brasilense Sp7 and its mutant defective in lectin activity, A. brasilense Sp7.2.3. Differences in plant response to the action of the lectins from these two strains were established. On the basis of the obtained data, a model was proposed for lectin-assisted induction of resistance, according to which the lectin effect on the roots of seedlings results in accumulation of free salicylic acid, which inhibits catalase activity, ultimately leading to accumulation of hydrogen peroxide and to formation of induced resistance.

Glycomacropeptide in children with phenylketonuria: does its phenylalanine content affect blood phenylalanine control?

Science.gov (United States)

Daly, A; Evans, S; Chahal, S; Santra, S; MacDonald, A

2017-08-01

In phenylketonuria (PKU), there are no data available for children with respect to evaluating casein glycomacropeptide (CGMP) as an alternative to phenylalanine-free protein substitutes [Phe-free L-amino acid (AA)]. CGMP contains a residual amount of phenylalanine, which may alter blood phenylalanine control. In a prospective 6-month pilot study, we investigated the effect on blood phenylalanine control of CGMP-amino acid (CGMP-AA) protein substitute in 22 PKU subjects (13 boys, nine girls), median age (range) 11 years (6-16 years). Twelve received CGMP-AA and nine received Phe-free L-AA, (1 CGMP-AA withdrawal). Subjects partially or wholly replaced Phe-free L-AA with CGMP-AA. If blood phenylalanine exceeded the target range, the CGMP-AA dose was reduced and replaced with Phe-free L-amino acids. The control group remained on Phe-free L-AAs. Phenylalanine, tyrosine and Phe : Tyr ratio concentrations were compared with the results for the previous year. In the CGMP-AA group, there was a significant increase in blood phenylalanine concentrations (pre-study, 275 μmol L -1 ; CGMP-AA, 317 μmol L -1 ; P = 0.02), a decrease in tyrosine concentrations (pre-study, 50 μmol L -1 ; CGMP-AA, 40 μmol L -1 ; P = 0.03) and an increase in Phe : Tyr ratios (pre-study, Phe : Tyr 4.9:1; CGMP-AA, Phe : Tyr 8:1; P = 0.02). In the control group there was a non-significant fall in phenylalanine concentrations (pre-study 325μmol/L: study 280μmol/L [p = 0.9], and no significant changes for tyrosine or phe/tyr ratios [p = 0.9]. Children taking the CGMP-AA found it more acceptable to L-AA. Blood phenylalanine control declined with CGMP-AA but, by titrating the dose of CGMP-AA, blood phenylalanine control remained within target range. The additional intake of phenylalanine may have contributed to the change in blood phenylalanine concentration. CGMP-AA use requires careful monitoring in children. © 2017 The British Dietetic Association Ltd.

[The relationship between activity and gene expression of phenylalanine ammonia-lyase and peel pitting in 'Fengjie' navel orange fruits].

Science.gov (United States)

Li, Zheng-Guo; Gao, Xue; Fan, Jing; Yang, Ying-Wu; Li, Dao-Gao; Kanellis, Angelos K

2006-06-01

Citrus fruit is prone to develop peel pitting during development and storage, which greatly decreases its fresh market value because of the deterioration of the peel. In the present study, we have examined the effect of different temperatures (15 degrees C and 4 degrees C), waxing and mechanical damage on the changes in the activity of phenylalanine ammonia-lyase (PAL) and the incidence of peel pitting in 'Fengjie' navel orange (Citrus sinensis Osbeck) fruits. The expression levels of PAL2, PAL6 genes in the peel during the development of peel pitting have been investigated through semi-quantitative PCR method. The incidence of peel pitting was greatly enhanced by waxing and mechanical damage and was decreased in lower temperature storage (4 degrees C) (Fig.1). Waxing and mechanical damage might be the important factors inducing peel pitting and suitable low temperature could decrease the incidence of this disease. The PAL activity increased during the whole storage period in accordance with the development of this pitting (Fig.2). The expression levels of PAL2 and PAL6 genes in damaged peel were higher than those in healthy peel and the expression of PAL2 is much more higher than that of PAL6 (Figs.4 and 5). The results suggested that the enzyme activity of PAL, along with the expression of PAL2 gene is highly related to this peel pitting occurred on 'Fengjie' navel orange fruits.

[Kinetic study on inhibition effects of dansyl-L-phenylalanine and L-phenylalanine on calf intestinal alkaline phosphatase].

Science.gov (United States)

Li, Li-Na; Wu, Yu-Qing; Buchet, René

2009-10-01

To evaluate the inhibition effect of dansyl-L-phenylalanine on calf intestinal alkaline phosphatase (CIAP), UV-Vis spectrophotometric method was employed. It was found that dansyl-L-phenylalanine can selectively inhibit CIAP. The kinetic inhibition processes of dansyl-L-phenylalanine and L-phenylalanine were comparatively studied. The authors' finding elucidates that at the optimized alkaline pH of alkaline phosphatase (pH 10.4) and 37 degrees C, dansyl-L-phenylalanine can inhibit alkaline phosphatase activity of CIAP efficiently and specifically, similar as L-phenylalanine. Both inhibition types were uncompetitive inhibition resulting from the double reciprocal curve fitting of upsilon versus substrate concentrations, and the inhibition constants Ki of both inhibitors were determined to be 2.3 and 1.1 mmol L(-1) respectively, both of which were at millimolar level. The investigation of the inhibition effect of dansyl modified L-phenylalanine on calf intestinal alkaline phosphatase not only helped get insight into the detailed inhibition mechanism of L-phenylalanine on tissue specific alkaline phosphatase, such as in the case of intestinal alkaline phosphatase, but also provided the possibility to employ fluorescence spectroscopy by labeling the specific inhibitors of alkaline phosphatase with chromophoric groups.

DNA Methylation Influences Chlorogenic Acid Biosynthesis in Lonicera japonica by Mediating LjbZIP8 to Regulate Phenylalanine Ammonia-Lyase 2 Expression

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Liangping Zha

2017-07-01

Full Text Available The content of active compounds differ in buds and flowers of Lonicera japonica (FLJ and L. japonica var. chinensis (rFLJ. Chlorogenic acid (CGAs were major active compounds of L. japonica and regarded as measurements for quality evaluation. However, little is known concerning the formation of active compounds at the molecular level. We quantified the major CGAs in FLJ and rFLJ, and found the concentrations of CGAs were higher in the buds of rFLJ than those of FLJ. Further analysis of CpG methylation of CGAs biosynthesis genes showed differences between FLJ and rFLJ in the 5′-UTR of phenylalanine ammonia-lyase 2 (PAL2. We identified 11 LjbZIP proteins and 24 rLjbZIP proteins with conserved basic leucine zipper domains, subcellular localization, and electrophoretic mobility shift assay showed that the transcription factor LjbZIP8 is a nuclear-localized protein that specifically binds to the G-box element of the LjPAL2 5′-UTR. Additionally, a transactivation assay and LjbZIP8 overexpression in transgenic tobacco indicated that LjbZIP8 could function as a repressor of transcription. Finally, treatment with 5-azacytidine decreased the transcription level of LjPAL2 and CGAs content in FLJ leaves. These results raise the possibility that DNA methylation might influence the recruitment of LjbZIP8, regulating PAL2 expression level and CGAs content in L. japonica.

Assessment of brain phenylalanine dynamics in phenylketonuria patients

International Nuclear Information System (INIS)

Bik-Multanowski, M.; Pietrzyk, J. J.; Pasowicz, M.; Banys, R.P.

2006-01-01

Phenylketonuria (PKU) is the most common inborn error of metabolism in man. Brain phenylalanine kinetics can determine neurological treatment outcome in phenylketonuria. The aim of our study wa sto test a simplified magnetic resonance spectroscopy method for assessment of brain phenylalanine dynamics in PKU patients. Brain phenylalanine concentration (measured by means of magnetic resonance spectroscopy) and blood phenylalanine concentrations changes occurring within 24 hours after oral phenylalanine loading were analyzed in 5 PKU patients. The brain/blood phenylalanine ratio in 3 persons with normal intelligence was lower than in 2 with borderline intelligence or mild mental retardation. In our opinion the proposed method could be useful for assessment of brain phenylalanine dynamics in PKU patients. (author)

Binding of radiation-induced phenylalanine radicals to DNA

International Nuclear Information System (INIS)

Schans, G.P. van der; Rijn, C.J.S. van; Bleichrodt, J.F.

1975-11-01

When an aqueous solution of double-stranded DNA of bacteriophage PM2 containing phenylalanine and saturated with N 2 O is irradiated with γ-rays, radiation-induced phenylalanine radicals are bound covalently. Under the conditions used about 25 phenylalanine molecules may be bound per lethal hit. Also for single-stranded PM2 DNA, most of the phenylalanine radicals bound are non-lethal. Evidence is presented that in double-stranded DNA an appreciable fraction of the single-strand breaks is induced by phenylalanine radicals. Radiation products of phenylalanine and the phenylalanine bound to the DNA decrease the sensitivity of the DNA to the induction of single-strand breaks. There are indications that the high efficiency of protection by radiation products of phenylalanine is due to their positive charge, which will result in a relatively high concentration of these compounds in the vicinity of the negatively charged DNA molecules

The rate of incorporation and degradation of phenylalanine-14C by tissue slices of roosters fed a phenylalanine-free diet

International Nuclear Information System (INIS)

Ishibashi, Teru; Kametaka, Masao

1975-01-01

To investigate the reason why adult roosters maintain nitrogen equilibrium on a phenylalanine-free diet for long periods, the rates of incorporation and of degradation of phenylalanine, tyrosine- and isoleucine- 14 C by tissue slices of roosters on the control, phenylalanine-free or isoleucine-free diets were measured. The degradation rate of isoleucine by liver and muscle slices decreased significantly for the isoleucine-free diet. However, the degradation rate of phenylalanine- 14 C by liver slices for the phenylalanine-free diet was not significantly lower than that for the control diet in contrast to the previous observation in vivo. The incorporation rates of 14 C into liver and muscle proteins were not affected by the dietary conditions in this experiment except in the case of phenylalanine- 14 C by muscle slices for the phenylalanine-free diet. (auth.)

Developmental role of phenylalanine-ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) genes during adventitious rooting of Juglans regia L. microshoots.

Science.gov (United States)

Cheniany, Monireh; Ganjeali, Ali

2016-12-01

Phenylalanine-ammonia-lyase and cinnamate-4-hydroxylase play important role in the phenylpropanoid pathway, which produces many biologically important secondary metabolites participating in normal plant development. Flavonol quercetin is the main representant of these compounds that has been identified in numerous Juglans spp. In this survey, the developmental expression patterns of PAL and C4H genes during in vitro rooting of two walnut cultivars 'Sunland' and 'Howard' was examined by RT-PCR. To understand the potential role in rooting, the changing pattern of endogenous content of quercetin was also analyzed by HPLC. The 'Sunland' with better capacity to root had more quercetin content during the "inductive phase" of rooting than 'Howard'. In each cultivar, the level of PAL transcripts showed the same behavior with the changing patterns of quercetin during root formation of microshoots. The positive correlation between the changes of quercetin and PAL-mRNA indicated that PAL gene may have an immediate effect on flavonoid pathway metabolites including quercetin. Although the behavioral change of C4H expression was similar in both cultivars during root formation (with significantly more level for 'Howard'), it was not coincide with the changes of quercerin concentrations. Our results showed that C4H function is important for the normal development, but its transcriptional regulation does not correlate with quercetin as an efficient phenolic compound for walnut rhizogenesis.

Phenylketonuria: Direct and indirect effects of phenylalanine.

Science.gov (United States)

Schlegel, Gudrun; Scholz, Ralf; Ullrich, Kurt; Santer, René; Rune, Gabriele M

2016-07-01

High phenylalanine concentrations in the brain due to dysfunctional phenylalanine hydroxylase (Pah) are considered to account for mental retardation in phenylketonuria (PKU). In this study, we treated hippocampal cultures with the amino acid in order to determine the role of elevated levels of phenylalanine in PKU-related mental retardation. Synapse density and dendritic length were dramatically reduced in hippocampal cultures treated with phenylalanine. Changes in cofilin expression and phosphorylation status, which were restored by NMDA, as well as reduced activation of the small GTPase Rac1, likely underlie these structural alterations. In the Pah(enu2) mouse, which carries a mutated Pah gene, we previously found higher synaptic density due to delayed synaptic pruning in response to insufficient microglia function. Microglia activity and C3 complement expression, both of which were reduced in the Pah(enu2) mouse, however, were unaffected in hippocampal cultures treated with phenylalanine. The lack of a direct effect of phenylalanine on microglia is the key to the opposite effects regarding synapse stability in vitro and in the Pah(enu2) mouse. Judging from our data, it appears that another player is required for the inactivation of microglia in the Pah(enu2) mouse, rather than high concentrations of phenylalanine alone. Altogether, the data underscore the necessity of a lifelong phenylalanine-restricted diet. Copyright © 2016 Elsevier Inc. All rights reserved.

Retroviral-mediated gene transfer of human phenylalanine hydroxylase into NIH 3T3 and hepatoma cells

Energy Technology Data Exchange (ETDEWEB)

Ledley, F.D.; Grenett, H.E.; McGinnis-Shelnutt, M.; Woo, S.L.C.

1986-01-01

Phenylketonuria (PKU) is caused by deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH). A full-length human PAH cDNA sequence has been inserted into pzip-neoSV(X), which is a retroviral vector containing the bacterial neo gene. The recombinant has been transfected into Psi2 cells, which provide synthesis of the retroviral capsid. Recombinant virus was detected in the culture medium of the transfected Psi2 cells, which is capable of transmitting the human PAH gene into mouse NIH 3T3 cells by infection leading to stable incorporation of the recombinant provirus. Infected cells express PAH mRNA, immunoreactive PAH protein, and exhibit pterin-dependent phenylaline hydroxylase activity. The recombinant virus is also capable of infecting a mouse hepatoma cell line that does not normal synthesize PAH. PAH activity is present in the cellular extracts and the entire hydroxylation system is reconstituted in the hepatoma cells infected with the recombinant viruses. Thus, recombinant viruses containing human PAH cDNA provide a means for introducing functional PAH into mammalian cells of hepatic origin and can potentially be introduced into whole animals as a model for somatic gene therapy for PKU.

Optimisation of trans-cinnamic acid and hydrocinnamyl alcohol production with recombinant Saccharomyces cerevisiae and identification of cinnamyl methyl ketone as a by-product.

Science.gov (United States)

Gottardi, Manuela; Grün, Peter; Bode, Helge B; Hoffmann, Thomas; Schwab, Wilfried; Oreb, Mislav; Boles, Eckhard

2017-12-01

Trans-cinnamic acid (tCA) and hydrocinnamyl alcohol (HcinOH) are valuable aromatic compounds with applications in the flavour, fragrance and cosmetic industry. They can be produced with recombinant yeasts from sugars via phenylalanine after expression of a phenylalanine ammonia lyase (PAL) and an aryl carboxylic acid reductase. Here, we show that in Saccharomyces cerevisiae a PAL enzyme from the bacterium Photorhabdus luminescens was superior to a previously used plant PAL enzyme for the production of tCA. Moreover, after expression of a UDP-glucose:cinnamate glucosyltransferase (FaGT2) from Fragaria x ananassa, tCA could be converted to cinnamoyl-D-glucose which is expected to be less toxic to the yeast cells. Production of tCA and HcinOH from glucose could be increased by eliminating feedback-regulated steps of aromatic amino acid biosynthesis and diminishing the decarboxylation step of the competing Ehrlich pathway. Finally, an unknown by-product resulting from further metabolisation of a carboligation product of cinnamaldehyde (cinALD) with activated acetaldehyde, mediated by pyruvate decarboxylases, could be identified as cinnamyl methyl ketone providing a new route for the biosynthesis of precursors, such as (2S,3R) 5-phenylpent-4-ene-2,3-diol, necessary for the chemical synthesis of specific biologically active drugs such as daunomycin. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fluctuations in phenylalanine concentrations in phenylketonuria: a review of possible relationships with outcomes.

Science.gov (United States)

Cleary, Maureen; Trefz, Friedrich; Muntau, Ania C; Feillet, François; van Spronsen, Francjan J; Burlina, Alberto; Bélanger-Quintana, Amaya; Giżewska, Maria; Gasteyger, Christoph; Bettiol, Esther; Blau, Nenad; MacDonald, Anita

2013-12-01

Fluctuations in blood phenylalanine concentrations may be an important determinant of intellectual outcome in patients with early and continuously treated phenylketonuria (PKU). This review evaluates the studies on phenylalanine fluctuations, factors affecting fluctuations, and if stabilizing phenylalanine concentrations affects outcomes, particularly neurocognitive outcome. Electronic literature searches of Embase and PubMed were performed for English-language publications, and the bibliographies of identified publications were also searched. In patients with PKU, phenylalanine concentrations are highest in the morning. Factors that can affect phenylalanine fluctuations include age, diet, timing and dosing of protein substitute and energy intake, dietary adherence, phenylalanine hydroxylase genotype, changes in dietary phenylalanine intake and protein metabolism, illness, and growth rate. Even distribution of phenylalanine-free protein substitute intake throughout 24h may reduce blood phenylalanine fluctuations. Patients responsive to and treated with 6R-tetrahydrobiopterin seem to have less fluctuation in their blood phenylalanine concentrations than controls. An increase in blood phenylalanine concentration may result in increased brain and cerebrospinal fluid phenylalanine concentrations within hours. Although some evidence suggests that stabilization of blood phenylalanine concentrations may have benefits in patients with PKU, more studies are needed to distinguish the effects of blood phenylalanine fluctuations from those of poor metabolic control. © 2013.

Phase 1 Trial of Subcutaneous rAvPAL-PEG in Subjects with Phenylketonuria

Science.gov (United States)

Longo, Nicola; Harding, Cary O.; Burton, Barbara K.; Grange, Dorothy K.; Vockley, Jerry; Wasserstein, Melissa; Rice, Gregory M.; Musson, Donald G.; Gu, Zhonghua; Sile, Saba

2014-01-01

Objective Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. A phenylalanine-restricted diet initiated early in life can ameliorate the toxic effects of phenylalanine. However, the diet is onerous and compliance is extremely difficult. Phenylalanine ammonia lyase (PAL) is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. This Phase 1, multicenter clinical trial evaluated the safety, tolerability, pharmacokinetics and efficacy of rAvPAL-PEG (recombinant Anabaena variabilis PAL produced in E. coli conjugated with polyethylene glycol [PEG] to reduce immunogenicity) in reducing phenylalanine levels in subjects with phenylketonuria. Methods Single subcutaneous injections of rAvPAL-PEG in escalating doses (0·001, 0·003, 0·01, 0·03, and 0·1 mg/kg) were administered to 25 adults with phenylketonuria recruited from those attending metabolic clinics in North America whose blood phenylalanine concentrations were ≥600 μmol/L. Results The most frequently reported adverse events were injection-site reactions and dizziness. Reactions were self-limited without sequelae. During the trial, two subjects had adverse reactions to intramuscular (IM) medroxyprogesterone acetate, a drug containing polyethylene glycol as an excipient. Three subjects developed a generalized skin rash at the highest rAvPAL-PEG dose (0·1 mg/kg). Drug levels peaked ∼5 days after the injection. Treatment was effective in reducing blood phenylalanine in all five subjects receiving the highest dose (0·1 mg/kg, mean percent change of -58 from baseline), with a nadir ∼6 days after injection and inverse correlation between drug and phenylalanine concentrations in plasma. Phenylalanine concentrations returned to near-baseline levels ∼20 days after the single injection. Conclusions

Phenylalanine kinetics in human adipose tissue.

OpenAIRE

Coppack, S W; Persson, M; Miles, J M

1996-01-01

Very little is known about the regulation of protein metabolism in adipose tissue. In this study systemic, adipose tissue, and forearm phenylalanine kinetics were determined in healthy postabsorptive volunteers before and during a 2-h glucose infusion (7 mg.kg-1.min-1). [3H]Phenylalanine was infused and blood was sampled from a radial artery, a subcutaneous abdominal vein, and a deep forearm vein. Adipose tissue and forearm blood flow were measured with 133Xe and plethysmography, respectively...

Surface modification of hydroxyapatite nanoparticles by poly(L-phenylalanine) via ROP of L-phenylalanine N-carboxyanhydride (Pha-NCA)

International Nuclear Information System (INIS)

Dai Yanfeng; Xu Min; Wei Junchao; Zhang Haobin; Chen Yiwang

2012-01-01

The surface of hydroxyapatite nanoparticles was modified by poly(L-phenylalanine) via the ring opening polymerization (ROP) of L-phenylalanine N-carboxyanhydride. The preparation procedure was monitored by Fourier transform infrared spectroscopy (FTIR), and the modified hydroxyapatite was characterized by thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that the surface grafting amounts of poly(L-phenylalanine) on HA ranging from 20.26% to 38.92% can be achieved by tuning the reaction condition. The XRD patterns demonstrated that the crystalline structure of the modified hydroxyapatite was nearly the same with that of HA, implying that the ROP was an efficient surface modification method. The MTT assay proved that the biocompatibility of modified HA was very good, which showed the potential application of modified HA in bone tissue engineering.

Human phenylalanine hydroxylase is activated by H2O2: a novel mechanism for increasing the L-tyrosine supply for melanogenesis in melanocytes

International Nuclear Information System (INIS)

Schallreuter, Karin U.; Wazir, Umar; Kothari, Sonal; Gibbons, Nicholas C.J.; Moore, Jeremy; Wood, John M.

2004-01-01

Epidermal phenylalanine hydroxylase (PAH) produces L-tyrosine from the essential amino acid L-phenylalanine supporting melanogenesis in human melanocytes. Those PAH activities increase linearly in the different skin phototypes I-VI (Fitzpatrick classification) and also increase up to 24 h after UVB light with only one minimal erythemal dose. Since UVB generates also H 2 O 2 , we here asked the question whether this reactive oxygen species could influence the activity of pure recombinant human PAH. Under saturating conditions with the substrate L-phenylalanine (1 x 10 -3 M), the V max for enzyme activity increased 4-fold by H 2 O 2 (>2.0 x 10 -3 M). Lineweaver-Burk analysis identified a mixed activation mechanism involving both the regulatory and catalytic domains of PAH. Hyperchem molecular modelling and Deep View analysis support oxidation of the single Trp 120 residue to 5-OH-Trp 120 by H 2 O 2 causing a conformational change in the regulatory domain. PAH was still activated by H 2 O 2 in the presence of the electron donor/cofactor 6(R)-L-erythro-5,6,7,8-tetrahydrobiopterin despite slow oxidation of this cofactor. In vivo FT-Raman spectroscopy confirmed decreased epidermal phenylalanine in association with increased tyrosine after UVB exposure. Hence, generation of H 2 O 2 by UVB can activate epidermal PAH leading to an increased L-tyrosine pool for melanogenesis

Differential metabolism of L-phenylalanine in the formation of aromatic volatiles in melon (Cucumis melo L.) fruit.

Science.gov (United States)

Gonda, Itay; Davidovich-Rikanati, Rachel; Bar, Einat; Lev, Shery; Jhirad, Pliaa; Meshulam, Yuval; Wissotsky, Guy; Portnoy, Vitaly; Burger, Joseph; Schaffer, Arthur A; Tadmor, Yaakov; Giovannoni, James J; Fei, Zhangjun; Fait, Aaron; Katzir, Nurit; Lewinsohn, Efraim

2018-04-01

Studies on the active pathways and the genes involved in the biosynthesis of L-phenylalanine-derived volatiles in fleshy fruits are sparse. Melon fruit rinds converted stable-isotope labeled L-phe into more than 20 volatiles. Phenylpropanes, phenylpropenes and benzenoids are apparently produced via the well-known phenylpropanoid pathway involving phenylalanine ammonia lyase (PAL) and being (E)-cinnamic acid a key intermediate. Phenethyl derivatives seemed to be derived from L-phe via a separate biosynthetic route not involving (E)-cinnamic acid and PAL. To explore for a biosynthetic route to (E)-cinnamaldehyde in melon rinds, soluble protein cell-free extracts were assayed with (E)-cinnamic acid, CoA, ATP, NADPH and MgSO 4 , producing (E)-cinnamaldehyde in vitro. In this context, we characterized CmCNL, a gene encoding for (E)-cinnamic acid:coenzyme A ligase, inferred to be involved in the biosynthesis of (E)-cinnamaldehyde. Additionally we describe CmBAMT, a SABATH gene family member encoding a benzoic acid:S-adenosyl-L-methionine carboxyl methyltransferase having a role in the accumulation of methyl benzoate. Our approach leads to a more comprehensive understanding of L-phe metabolism into aromatic volatiles in melon fruit. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fluorinated Phenylalanine Precursor Resistance in Yeast

Directory of Open Access Journals (Sweden)

Ian S. Murdoch

2018-06-01

Full Text Available Development of a counter-selection method for phenylalanine auxotrophy could be a useful tool in the repertoire of yeast genetics. Fluorinated and sulfurated precursors of phenylalanine were tested for toxicity in Saccharomyces cerevisiae. One such precursor, 4-fluorophenylpyruvate (FPP, was found to be toxic to several strains from the Saccharomyces and Candida genera. Toxicity was partially dependent on ARO8 and ARO9, and correlated with a strain’s ability to convert FPP into 4-fluorophenylalanine (FPA. Thus, strains with deletions in ARO8 and ARO9, having a mild phenylalanine auxotrophy, could be separated from a culture of wild-type strains using FPP. Tetrad analysis suggests FPP resistance in one strain is due to two genes. Strains resistant to FPA have previously been shown to exhibit increased phenylethanol production. However, FPP resistant isolates did not follow this trend. These results suggest that FPP could effectively be used for counter-selection but not for enhanced phenylethanol production.

The conversion of phenylalanine to tyrosine in man. Direct measurement by continuous intravenous tracer infusions of L-[ring-2H5]phenylalanine and L-[1-13C] tyrosine in the postabsorptive state

International Nuclear Information System (INIS)

Clarke, J.T.; Bier, D.M.

1982-01-01

Steady state phenylalanine and tyrosine turnover and the rate of conversion of phenylalanine of tyrosine in vivo were determined in 6 healthy postabsorptive adult volunteers. Continuous infusions of tracer amounts of L-[ring- 2 H5]phenylalanine were determined intravenously for 13-14 hr. After 9-10 hr, a priming dose followed by a continuous infusion of L-[1- 13 C]tyrosine was added and maintained, along with the [ 2 H5]phenylalanine infusion, for 4 hr. Venous plasma samples were obtained before the initiation of each infusion and every 30 min during the course of the combined [ 2 H5]phenylalanine and [ 13 C]tyrosine infusion for determination of isotopic enrichments of [ 2 H5]phenylalanine, [ 13 C]tyrosine, and [ 2 H4]tyrosine by gas chromatograph-mass spectrometric analysis of the N-trifluoroacetyl-, methyl ester derivatives of the amino acids. Calculated from the observed enrichments, free phenylalanine and tyrosine turnover rates were 36.1 +/- 5.1 mumole . kg-1 . h-1 and 39.8 +/- 3.5 mumole . kg-1 . h-1, respectively. Phenylalanine was converted to tyrosine at the rate of 5.83 +/- 0.59 mumole . kg-1 . h-1, accounting for approximately 16% of either the phenylalanine or the tyrosine flux. The results indicate that the normal basal steady state phenylalanine hydroxylase activity in vivo in man is lower than that obtained from phenylalanine loading studies. This supports the existence of some type of substance activation of the enzyme as reflected in the previously reported exponential relationship between phenylalanine concentration and phenylalanine hydroxylase activity in vitro. The use of continuous simultaneous infusions of tracer amounts of stable isotope-labeled phenylalanine and tyrosine provides a direct means for studying physiological regulation of phenylalanine hydroxylase activity in vivo

Amino acid tolerance test using L-β-phenylalanine-125I

International Nuclear Information System (INIS)

Hafiez, A.A.; Megahed, Y.M.; Ismail, A.A.; Abdel-Wahab, M.F.; Khater, R.A.

1978-01-01

An amino acid tolerance test is described. L-β-phenylalanine- 125 I was used as representative of L-amino acids. The change in radioactivity of the blood after giving a test dose of tagged L-β-phenylalanine was also investigated. L-β-phenylalanine- 125 I tolerance curves were found to be irreproducible when the test dose was given without a carrier. The addition of 2.5 g untagged phenylalanine as a carrier to the test dose allowed a reproducible and precise type of tolerance curves. Metformin in a dose of 0.5 g t.d.s. for three days induced an inhibitory effect on amino acid absorption in normal persons. (author)

Phenylalanine ammonia lyase from Arabidopsis thaliana (AtPAL2): A potent MIO-enzyme for the synthesis of non-canonical aromatic alpha-amino acids: Part I: Comparative characterization to the enzymes from Petroselinum crispum (PcPAL1) and Rhodosporidium toruloides (RtPAL).

Science.gov (United States)

Dreßen, Alana; Hilberath, Thomas; Mackfeld, Ursula; Billmeier, Arne; Rudat, Jens; Pohl, Martina

2017-09-20

Phenylalanine ammonia lyase (PAL) from Arabidopsis thaliana (AtPAL2) was comparatively characterized to the well-studied enzyme from parsley (PcPAL1) and Rhodosporidium toruloides (RtPAL) with respect to kinetic parameters for the deamination and the amination reaction, pH- and temperature optima and the substrate range of the amination reaction. Whereas both plant enzymes are specific for phenylalanine, the bifunctional enzyme from Rhodosporidium toruloides shows K M -values for L-Phe and L-Tyr in the same order of magnitude and, compared to both plant enzymes, a 10-15-fold higher activity. At 30°C all enzymes were sufficiently stable with half-lives of 3.4days (PcPAL1), 4.6days (AtPAL2) and 9.7days (RtPAL/TAL). Very good results for the amination of various trans-cinnamic acid derivatives were obtained using E. coli cells as whole cell biocatalysts in ammonium carbonate buffer. Investigation of the substrate ranges gave interesting results for the newly tested enzymes from A. thaliana and R. toruloides. Only the latter accepts besides 4-hydroxy-CA also 3-methoxy-4-hydroxy-CA as a substrate, which is an interesting intermediate for the formation of pharmaceutically relevant L-Dopa. AtPAL2 is a very good catalyst for the formation of (S)-3-F-Phe, (S)-4-F-Phe and (S)-2-Cl-Phe. Such non-canonical amino acids are valuable building blocks for the formation of various drug molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

Elevated levels of plasma phenylalanine in schizophrenia: a guanosine triphosphate cyclohydrolase-1 metabolic pathway abnormality?

Directory of Open Access Journals (Sweden)

Olaoluwa Okusaga

Full Text Available BACKGROUND: Phenylalanine and tyrosine are precursor amino acids required for the synthesis of dopamine, the main neurotransmitter implicated in the neurobiology of schizophrenia. Inflammation, increasingly implicated in schizophrenia, can impair the function of the enzyme Phenylalanine hydroxylase (PAH; which catalyzes the conversion of phenylalanine to tyrosine and thus lead to elevated phenylalanine levels and reduced tyrosine levels. This study aimed to compare phenylalanine, tyrosine, and their ratio (a proxy for PAH function in a relatively large sample of schizophrenia patients and healthy controls. METHODS: We measured non-fasting plasma phenylalanine and tyrosine in 950 schizophrenia patients and 1000 healthy controls. We carried out multivariate analyses to compare log transformed phenylalanine, tyrosine, and phenylalanine:tyrosine ratio between patients and controls. RESULTS: Compared to controls, schizophrenia patients had higher phenylalanine (p<0.0001 and phenylalanine: tyrosine ratio (p<0.0001 but tyrosine did not differ between the two groups (p = 0.596. CONCLUSIONS: Elevated phenylalanine and phenylalanine:tyrosine ratio in the blood of schizophrenia patients have to be replicated in longitudinal studies. The results may relate to an abnormal PAH function in schizophrenia that could become a target for novel preventative and interventional approaches.

Formation of Hydroxylamine from Ammonia and Hydroxyl Radicals

Science.gov (United States)

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.

Minimally invasive (13)C-breath test to examine phenylalanine metabolism in children with phenylketonuria.

Science.gov (United States)

Turki, Abrar; Murthy, Gayathri; Ueda, Keiko; Cheng, Barbara; Giezen, Alette; Stockler-Ipsiroglu, Sylvia; Elango, Rajavel

2015-01-01

Phenylketonuria (PKU) is an autosomal recessive disorder caused by deficiency of hepatic phenylalanine hydroxylase (PAH) leading to increased levels of phenylalanine in the plasma. Phenylalanine levels and phenylalanine hydroxylase (PAH) activity monitoring are currently limited to conventional blood dot testing. 1-(13)C-phenylalanine, a stable isotope can be used to examine phenylalanine metabolism, as the conversion of phenylalanine to tyrosine occurs in vivo via PAH and subsequently releases the carboxyl labeled (13)C as (13)CO2 in breath. Our objective was to examine phenylalanine metabolism in children with PKU using a minimally-invasive 1-(13)C-phenylalanine breath test ((13)C-PBT). Nine children (7 M: 2 F, mean age 12.5 ± 2.87 y) with PKU participated in the study twice: once before and once after sapropterin supplementation. Children were provided 6 mg/kg oral dose of 1-(13)C-phenylalanine and breath samples were collected at 20 min intervals for a period of 2h. Rate of CO2 production was measured at 60 min post-oral dose using indirect calorimetry. The percentage of 1-(13)C-phenylalanine exhaled as (13)CO2 was measured over a 2h period. Prior to studying children with PKU, we tested the study protocol in healthy children (n = 6; 4M: 2F, mean age 10.2 ± 2.48 y) as proof of principle. Production of a peak enrichment (Cmax) of (13)CO2 (% of dose) in all healthy children occurred at 20 min ranging from 17-29% of dose, with a subsequent return to ~5% by the end of 2h. Production of (13)CO2 from 1-(13)C-phenylalanine in all children with PKU prior to sapropterin treatment remained low. Following sapropterin supplementation for a week, production of (13)CO2 significantly increased in five children with a subsequent decline in blood phenylalanine levels, suggesting improved PAH activity. Sapropterin treatment was not effective in three children whose (13)CO2 production remained unchanged, and did not show a reduction in blood phenylalanine levels and improvement

Sodium sulfite pH-buffering effect for improved xylose-phenylalanine conversion to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine during an aqueous Maillard reaction.

Science.gov (United States)

Cui, Heping; Duhoranimana, Emmanuel; Karangwa, Eric; Jia, Chengsheng; Zhang, Xiaoming

2018-04-25

The yield of the Maillard reaction intermediate (MRI), prepared in aqueous medium, is usually unsatisfactory. However, the addition of sodium sulfite could improve the conversion of xylose-phenylalanine (Xyl-Phe) to the MRI (N-(1-deoxy-d-xylulos-1-yl)-phenylalanine) in aqueous medium. Sodium sulfite (Na 2 SO 3 ) showed a significant pH-buffering effect during the Maillard reaction, which accounted for its facilitation of the N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. The results revealed that the pH could be maintained at a relatively high level (above 7.0) for an optimized pH-buffering effect when Na 2 SO 3 (4.0%) was added before the reaction of Xyl-Phe. Thus, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine increased from 47.23% to 74.86%. Furthermore, the addition moment of Na 2 SO 3 and corresponding solution pH were crucial factors in regulating the pH-buffering effect of Na 2 SO 3 on N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. Based on the pH-buffering effect of Na 2 SO 3 and maintaining the optimal pH 7.4 relatively stable, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine was successfully improved. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of streptozotocin-induced diabetes on phenylalanine hydroxylase expression in rat liver.

OpenAIRE

Taylor, D S; Dahl, H H; Mercer, J F; Green, A K; Fisher, M J

1989-01-01

The impact of experimentally induced diabetes on the expression of rat liver phenylalanine hydroxylase has been investigated. A significant elevation in maximal enzymic activity was observed in diabetes. This was associated with significant increases in the amount of enzyme, the phenylalanine hydroxylase-specific translational activity of hepatic RNA and the abundance of phenylalanine hydroxylase-specific mRNA. These changes in phenylalanine hydroxylase expression were not observed when diabe...

Wound-induced ethylene synthesis and expression and formation of 1-aminocyclopropane-1-carboxylate (ACC) synthase, ACC oxidase, phenylalanine ammonia-lyase, and peroxidase in wounded mesocarp tissue of Cucurbita maxima.

Science.gov (United States)

Kato, M; Hayakawa, Y; Hyodo, H; Ikoma, Y; Yano, M

2000-04-01

1-Aminocyclopropane-1-carboxylate (ACC) synthase was rapidly induced in mesocarp tissue of Cucurbita maxima after wounding in the cut surface layer in 1 mm thickness (ca. 9 cells) (first layer) in both the enzyme activity and the levels of transcript. This led to a rapid accumulation of ACC and hence ethylene production. In the inside tissue (1-2 mm) (second layer), no significant induction of ACC synthase was observed, which resulted in a low level of ACC, although ethylene was evolved at a much lower rate than the first one. In contrast to ACC synthase, ACC oxidase was induced markedly in both the first and second layers and the development of its activity and the levels of mRNA remained high until later stages. It was considered that wound ethylene was closely associated with the development of ACC oxidase, since 2,5-norbornadiene (NBD), an inhibitor of ethylene action, substantially suppressed it. Phenylalanine ammonia-lyase (PAL) greatly increased in activity after wounding similarly to that of ACC synthase, in which increase in PAL activity occurred predominantly in the first layer. Induction of peroxidase activity after wounding had a close correlation in profile with that of ACC oxidase in that marked increases in the activity were observed in both the first and second layers and were strongly suppressed by NBD application. Four peroxidase isozymes were found by PAGE, among which a fraction was newly detected after wounding.

Phenylalanine-coupled solid lipid nanoparticles for brain tumor targeting

Energy Technology Data Exchange (ETDEWEB)

Kharya, Parul; Jain, Ashish; Gulbake, Arvind; Shilpi, Satish; Jain, Ankit; Hurkat, Pooja [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India); Majumdar, Subrata [Bose Institute, Division of Molecular Medicine (India); Jain, Sanjay K., E-mail: drskjainin@yahoo.com [Dr. Hari Singh Gour University, Pharmaceutical Research Projects Laboratory, Department of Pharmaceutical Sciences (India)

2013-11-15

The purpose of this study is to investigate the targeting potential of amino acid (phenylalanine)-coupled solid lipid nanoparticles (SLN) loaded with ionically complexed doxorubicin HCl (Dox). Ionic complexation was used to enhance the loading efficiency and release characteristics of water soluble form of Dox. l-Type amino acid transporters (LAT1) are highly expressed on blood brain barrier as well as on many brain cancer cells, thus targeting LAT1 using phenylalanine improved anticancer activity of prepared nanocarrier. The phenylalanine-coupled SLN were characterized by fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, particle size, zeta potential, entrapment efficiency and in vitro release. The particle size of the resulting SLN was found to be in the range of 163.3 ± 5.2 to 113.0 ± 2.6 nm, with a slightly negative surface charge. In ex vivo study on C6 glioma cell lines, the cellular cytotoxicity of the SLN was highly increased when coupled with phenylalanine. In addition, stealthing sheath of PEG present on the surface of the SLN enhanced the cellular uptake of the SLN on C6 glioma cell line. Results of biodistribution and fluorescence studies clearly revealed that phenylalanine-coupled SLN could deliver high amount of drug into the brain tumor cells and showed the brain-targeting potential.

PKU: high plasma phenylalanine concentrations are associated with increased prevalence of mood swings.

Science.gov (United States)

Anjema, Karen; van Rijn, Margreet; Verkerk, Paul H; Burgerhof, Johannes G M; Heiner-Fokkema, M Rebecca; van Spronsen, Francjan J

2011-11-01

In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early treated PKU patients (median age 8.5, range 0-35 years) participated (median phenylalanine concentration in total sample 277 (range 89-1171) μmol/l; and in patients introvert or extravert behavior. The interviewer as well as the respondents were blinded with regard to the phenylalanine concentration. Patients reported less deviant behavior compared to close environment. Mood swings were positively associated with phenylalanine concentrations in the total group (P=0.039) and patients introvert and extravert behavior were not statistically significant. there is a positive association between phenylalanine concentrations and mood swings. Copyright © 2011 Elsevier Inc. All rights reserved.

Biocatalytic Enantioselective Synthesis of N-Substituted Aspartic Acids by Aspartate Ammonia Lyase

NARCIS (Netherlands)

Weiner, Barbara; Poelarends, Gerrit J.; Janssen, Dick B.; Feringa, Ben L.

2008-01-01

The gene encoding aspartate ammonia lyase (aspB) from Bacillus sp. YM55-1 has been cloned and overexpressed, and the recombinant enzyme containing a C-terminal His6 tag has been purified to homogeneity and subjected to kinetic characterization. Kinetic studies have shown that the His6 tag does not

A phenylalanine ammonia-lyase ortholog (PkPAL1) from Picrorhiza kurrooa Royle ex. Benth: molecular cloning, promoter analysis and response to biotic and abiotic elicitors.

Science.gov (United States)

Bhat, Wajid Waheed; Razdan, Sumeer; Rana, Satiander; Dhar, Niha; Wani, Tariq Ahmad; Qazi, Parvaiz; Vishwakarma, Ram; Lattoo, Surrinder K

2014-09-01

Picrorhiza kurrooa Royle ex Benth. is a highly reputed medicinal herb utilised in the preparation of a number of herbal drug formulations, principally due to the presence of novel monoterpene iridoid glycosides kenned as picrosides. Phenylalanine ammonia-lyase catalyses an important rate-limiting step in phenylpropanoid pathway and supplies precursors like cinnamic acid, vanillic acid, ferulic acid, etc., to a variety of secondary metabolites including picrosides. The imperilled status of P. kurrooa coupled with lack of information regarding biogenesis of picrosides necessitates deciphering the biosynthetic pathway for picrosides. In the present study, a PAL gene, designated PkPAL1 was isolated from P. kurrooa. The cDNA is 2312 bp in length, consisting of an ORF of 2142 bp encoding for a 713 amino acid protein having a predicted molecular weight of 77.66 kDa and an isoelectric point of pH 6.82. qRT-PCR analysis of various tissues of P. kurrooa showed that PkPAL1 transcript levels were highest in the leaves, consistent with picroside accumulation pattern. Using Genome walking, a 718 bp promoter region was also isolated resulting in identification of distinct cis-regulatory elements including TGA-element, TGACG-motif, CGTCA-motif, etc. qRT-PCR indicated up-regulation of PkPAL1 by methyl jasmonate, salicylic acid, 2,4-dicholorophenoxy acetic acid and UV-B elicitations that corroborated positively with the identified cis-elements within the promoter region. Moreover, altitude was found to have a positive effect on the PkPAL1 transcript levels, driving the expression of PkPAL1 abundantly. Based on docking analysis, we identified eight residues as potentially essential for substrate binding in PkPAL1. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of Phenylalanine and Tyrosine by High Performance Liquid Chromatography-Tandem Mass Spectrometry.

Science.gov (United States)

Peat, Judy; Garg, Uttam

2016-01-01

Hyperphenylalaninemia/phenylketonuria (PKU) is one of the most common inborn errors of amino acid metabolism affecting about 1:15,000 infants in the United States. PKU is an autosomal recessive disorder that if untreated results in mental retardation. The most common cause of PKU is deficiency of the enzyme phenylalanine hydroxylase that converts phenylalanine to tyrosine. Tyrosine deficiency results in impaired synthesis of catecholamines and thyroxine. Less commonly, it can result from defects in the synthesis or regeneration of tetrahydrobiopterin (BH4), an essential cofactor for the enzyme phenylalanine hydroxylase. Increased phenylalanine and decreased tyrosine in blood are used in the diagnosis and follow-up of patients with PKU. LC/MS/MS method is described for the quantification of phenylalanine and tyrosine.

Phenylalanine metabolism in isolated rat liver cells. Effects of glucagon and diabetes.

OpenAIRE

Carr, F P; Pogson, C I

1981-01-01

1. Methods are described for monitoring the metabolic flux through phenylalanine hydroxylase, the tyrosine catabolic pathway and phenylalanine: pyruvate transaminase in isolated liver cell incubations. 2. The relationship between hydroxylase flux and phenylalanine concentration is sigmoidal. 3. Glucagon increases hydroxylase activity at low, near-physiological, substrate concentrations only. The hormone does not affect the rate of formation of phenylpyruvate. 4. Experimental diabetes (for 10 ...

Eosin-sensitized photooxidation of substituted phenylalanines and tyrosines

Energy Technology Data Exchange (ETDEWEB)

Rizzuto, F.; Spikes, J.D.

1977-01-01

The cosin-sensitized photooxidation of tyrosine and a number of compounds related to tyrosine (substituted phenylalanines) was studied by steady-state kinetic and flash photolysis techniques. In particular, the role of the phenolic group and the amino and carboxyl groups of the alanyl side chain in the photooxidation mechanism was investigated in detail. Several relationships between substrate structure and susceptibility to photooxidation as well as effects of substrate structure on photooxidation mechanisms were found. For example, phenylalanine is not photooxidizable, but substitution of electron-donating (activating) groups such as -OH (as in tyrosine) or -NH/sub 2/ (as in p-aminophenylalanine) results in rapidly photooxidized derivatives. However, substituting deactivating groups such as -Cl (as in p-chlorophenylalanine) or weakly activating groups such as -OCH/sub 3/ (as in 4-methoxyphenylalanine) result in non-photooxidizable derivatives. Substitution of additional activating groups to the ring of hydroxy-substituted phenylalanines results in increased rates of photooxidation, whereas additional deactivating groups result in decreased photooxidation rates. The rate-determining step in the photooxidation mechanism is shown to be dependent on the presence and position of an electron-donating substituent on the benzenoid ring. Only minor involvement of the side chain amino and carboxyl groups was found. Both singlet oxygen and hydrogen abstraction mechanisms are involved in the eosin-sensitized photooxidation of hydroxy-substituted phenylalanines (e.g., tyrosine). The hydrogen abstraction mechanism probably predominates at both pH 8 and 11.

Bioproduction of L-Aspartic Acid and Cinnamic Acid by L-Aspartate Ammonia Lyase from Pseudomonas aeruginosa PAO1.

Science.gov (United States)

Patel, Arti T; Akhani, Rekha C; Patel, Manisha J; Dedania, Samir R; Patel, Darshan H

2017-06-01

Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) catalyses the reversible amination and deamination of L-aspartic acid to fumaric acid which can be used to produce important biochemical. In this study, we have explored the characteristics of aspartase from Pseudomonas aeruginosa PAO1 (PA-AspA). To overproduce PA-AspA, the 1425-bp gene was introduced in Escherichia coli BL21 and purified. A 51.0-kDa protein was observed as a homogenous purified protein on SDS-PAGE. The enzyme was optimally active at pH 8.0 and 35 °C. PA-AspA has retained 56% activity after 7 days of incubation at 35 °C, which displays the hyperthermostablility characteristics of the enzyme. PA-AspA is activated in the presence of metal ions and Mg2+ is found to be most effective. Among the substrates tested for specificity of PA-AspA, L-phenylalanine (38.35 ± 2.68) showed the highest specific activity followed by L-aspartic acid (31.21 ± 3.31) and fumarate (5.42 ± 2.94). K m values for L-phenylalanine, L-aspartic acid and fumarate were 1.71 mM, 0.346 μM and 2 M, respectively. The catalytic efficiency (k cat /K m ) for L-aspartic acid (14.18 s -1  mM -1 ) was higher than that for L-phenylalanine (4.65 s -1  mM -1 ). For bioconversion, from an initial concentration of 1000 mM of fumarate and 30 mM of L-phenylalanine, PA-AspA was found to convert 395.31 μM L-aspartic acid and 3.47 mM cinnamic acid, respectively.

Analog kefir production with a low phenylalanine for Phenylketonuria

OpenAIRE

Amir Yari; Yousef Ramezan

2017-01-01

Phenylketonuria (PKU) is one of the most prevalent types of hereditary metabolic disorders which is caused due to an absence or reduction of the activity of the Phenylalanine hydroxylase enzyme in the liver which in turn, inhibits the transformation of phenylalanine (Phe) to tyrosine. In clinical terms, this disorder is displayed with severe, permanent and irreversible mental retardation. This research was aimed at development of a highly nutrient and acceptable suitable analogue Kefir drink ...

Use of deuterated tyrosine and phenylalanine in the study of catecholamine and aromatic acid metabolism

International Nuclear Information System (INIS)

Curtius, H.C.; Redweik, U.; Steinmann, B.; Leimbacher, W.; Wegmann, H.

1975-01-01

Deuterated tyrosine and phenylalanine have been used for the study of their respective metabolism in patients with phenylketonuria (PKU) and in healthy persons. Urinary excretion of dopamine and its metabolites was studied by GC-MS after oral administration of deuterated L-tyrosine in 2 patients with PKU and in normal controls at low and high plasma phenylalanine levels. From these studies it seemed that the in vivo tyrosine 3-hydroxylase activity and thus the formation of L-dopa depend on the phenylalanine concentration in plasma and also in tissues. After loading 3 mentally retarded patients with 3,5-[ 2 H 2 ]-4-hydroxyphenylalanine, we found, among others, excretion of deuterated m-hydroxyphenyl-hydracrylic acid, p-hydroxymandelic acid, p-hydroxybenzoic acid, p-hydroxyhippuric acid, benzoic acid and hippuric acid. An intramolecular rearrangement is postulated. Deuterated phenylalanine was used to investigate phenylalanine and dopa metabolism in PKU. In addition, one untreated person with PKU of normal intelligence and normal excretion of catecholamines at high plasma phenylalanine concentration was investigated in order to see whether there exists an alternative metabolic pathway from phenylalanine to dopa formation

Ammonia blood test

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003506.htm Ammonia blood test To use the sharing features on this page, ... Encephalopathy - ammonia; Cirrhosis - ammonia; Liver failure - ammonia Images Blood test References Chernecky CC, Berger BJ. Ammonia (NH3) - blood ...

Recombinant Brucella abortus gene expressing immunogenic protein

Energy Technology Data Exchange (ETDEWEB)

Mayfield, J.E.; Tabatabai, L.B.

1991-06-11

This patent describes a synthetic recombinant DNA molecule containing a DNA sequence. It comprises a gene of Brucella abortus encoding an immunogenic protein having a molecular weight of approximately 31,000 daltons as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis under denaturing conditions, the protein having an isoelectric point around 4.9, and containing a twenty-five amino acid sequence from its amino terminal end consisting of Gln-Ala-Pro-Thr-Phe-Phe-Arg-Ile-Gly-Thr-Gly-Gly-Thr-Ala-Gly-Thr-Tyr-Tyr-Pro-Ile-Gly-Gly-Leu-Ile-Ala, wherein Gln, Ala, Pro, Thr, Phe, Arg, Ile, Gly, Tyr, and Leu, respectively, represent glutamine, alanine, proline, threonine, phenylalanine, arginine, isolecuine, glycine, tyrosine, and leucine.

Production of manganese peroxidase by white rot fungi from potato ...

African Journals Online (AJOL)

phenylalanine and L-tyrosine blocked the MnP biosynthetic pathway. Ammonium ion released from the L-phenylalanine by the L-phenylalanine ammonia-lyase participated in the repression of the MnP biosynthetic pathway of the strain L-25.

Highest Plasma Phenylalanine Levels in (Very Premature Infants on Intravenous Feeding; A Need for Concern.

Directory of Open Access Journals (Sweden)

Ernesto Cortés-Castell

Full Text Available To analyse the association in newborns between blood levels of phenylalanine and feeding method and gestational age.This observational, cross-sectional study included a sample of 11,829 infants between 2008 and 2013 in a Spanish region. Data were recorded on phenylalanine values, feeding method [breast, formula, mixed (breast plus formula, or partial or fully intravenous feeding], gestational age in weeks (<32, 32-37, ≥37, gender and days since birth at the moment of blood collection. Outcomes were [phenylalanine] and [phenylalanine] ≥95th percentile. Associations were analysed using multivariate models [linear (means difference and logistic regression (adjusted odds ratios].Higher phenylalanine values were associated with lower gestational age (p<0.001 and with intravenous feeding (p<0.001.The degree of prematurity and intravenous feeding influenced the plasma concentration of phenylalanine in the newborn. Caution should be taken in [phenylalanine] for newborns with intravenous feeding, monitoring them carefully. Very preterm infants given the recommended amount of amino acids should also be strictly monitored. These findings should be taken into consideration and call for adapting the amounts to the needs of the infant.

Ammonia intoxication

International Nuclear Information System (INIS)

Bessman, S.P.; Pal, N.

1982-01-01

Data is presented which shows that there is a relation between ammonia concentration in the blood and state of consciousness. The concentrations of GTP and ATP also relate both to the ammonia concentration in blood and the state of consciousness. The rate of protein synthesis in the brain as measured by the percent of intracellular counts that are incorporated into protein is also related to ammonia concentration. These findings of energy depletion and depressed synthesis resulting from energy depletion suggest that the primary lesion in ammonia intoxication involves the Krebs cycle. The greater effect of ammonia on GTP than on ATP metabolism supports the view that the primary site of action of ammonia is at the glutamate dehydrogenase-ketoglutarate reduction step - and is consistent with previous work on this subject. (H.K.)

Surface plasmon resonance spectroscopic study of UV-addressable phenylalanine sensing based on a self-assembled spirooxazine derivative monolayer

International Nuclear Information System (INIS)

Suk, Shinae; Suh, Hee-Jung; Gun An, Won; Kim, Jae-Ho; Jin, Sung-Ho; Kim, Sung-Hoon; Gal, Yeong-Soon; Koh, Kwangnak

2004-01-01

Light-addressable compounds are very interesting due to the possibilities of their practical use such as optical switches and memories or variable transmission materials. For example, transportation of phenylalanine across liposomal bilayers mediated by a photoresponsive carrier like spirooxazine through electrostatic interaction between phenylalanine and spirooxazine derivative. Thus, the spirooxazine is expected to form a UV-addressable phenylalanine sensing interface. In this study, we prepared phenylalanine sensing interface of a spirooxazine derivative by self-assembly technique and evaluated interaction between a spirooxazine moiety and phenylalanine with a surface plasmon resonance (SPR). The refractive index change of monolayer caused by interaction between a spirooxazine derivative and phenylalanine led to the SPR angle shifts upon UV irradiation. The SPR angle shift increased with increasing the concentration of phenylalanine solution. These results indicated that the spirooxazine derivative self-assembled monolayer (SAM) has an application potential for UV-addressable phenylalanine sensing

Detailed study of the plasma-activated catalytic generation of ammonia in N2-H2 plasmas

Science.gov (United States)

van Helden, J. H.; Wagemans, W.; Yagci, G.; Zijlmans, R. A. B.; Schram, D. C.; Engeln, R.; Lombardi, G.; Stancu, G. D.; Röpcke, J.

2007-02-01

We investigated the efficiency and formation mechanism of ammonia generation in recombining plasmas generated from mixtures of N2 and H2 under various plasma conditions. In contrast to the Haber-Bosch process, in which the molecules are dissociated on a catalytic surface, under these plasma conditions the precursor molecules, N2 and H2, are already dissociated in the gas phase. Surfaces are thus exposed to large fluxes of atomic N and H radicals. The ammonia production turns out to be strongly dependent on the fluxes of atomic N and H radicals to the surface. By optimizing the atomic N and H fluxes to the surface using an atomic nitrogen and hydrogen source ammonia can be formed efficiently, i.e., more than 10% of the total background pressure is measured to be ammonia. The results obtained show a strong similarity with results reported in literature, which were explained by the production of ammonia at the surface by stepwise addition reactions between adsorbed nitrogen and hydrogen containing radicals at the surface and incoming N and H containing radicals. Furthermore, our results indicate that the ammonia production is independent of wall material. The high fluxes of N and H radicals in our experiments result in a passivated surface, and the actual chemistry, leading to the formation of ammonia, takes place in an additional layer on top of this passivated surface.

Incorporation of exogenous L-phenylalanine into C-glycosylflavones in buckwheat cotyledons

International Nuclear Information System (INIS)

Margna, U.; Margna, E.

1978-01-01

By tracer experiments it was demonstrated that in excised buckwheat cotyledons L-phenylalanine fed exogeneously was incorporated predominantly into the luteolinic C-glycosylflavones orientin and iso-orientin, but not into their simpler apigeninic analogues vitexin and isovitexin, as it could be expected theoretically. Evidence is presented that L-phenylalanine supplied exogenously does not mix with the endogenous pool of that precursor, and that ratios of L-phenylalanine distribution between pathways of apigeninic and luteolinic C-glycosylflavones are different depending on wether the flavonoids are synthesized from endogenous or exogenous material. This phenomenon is suggested to be caused by the differences between enzyme complexes responsible for the biosynthesis of separate C-glycosylflavones in their capability of consuming common endogenous precursors. (author)

Ammonia Monitor

Science.gov (United States)

Sauer, Richard L. (Inventor); Akse, James R. (Inventor); Thompson, John O. (Inventor); Atwater, James E. (Inventor)

1999-01-01

Ammonia monitor and method of use are disclosed. A continuous, real-time determination of the concentration of ammonia in an aqueous process stream is possible over a wide dynamic range of concentrations. No reagents are required because pH is controlled by an in-line solid-phase base. Ammonia is selectively transported across a membrane from the process stream to an analytical stream to an analytical stream under pH control. The specific electrical conductance of the analytical stream is measured and used to determine the concentration of ammonia.

PKU : high plasma phenylalanine concentrations are associated with increased prevalence of mood swings

NARCIS (Netherlands)

Anjema, Karen; van Rijn, Margreet; Verkerk, Paul H; Burgerhof, Johannes G M; van Spronsen, Francjan J; Fokkema, Margaretha

2011-01-01

UNLABELLED: In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early

PKU : high plasma phenylalanine concentrations are associated with increased prevalence of mood swings

NARCIS (Netherlands)

Anjema, Karen; van Rijn, Margreet; Verkerk, Paul H; Burgerhof, Johannes G M; van Spronsen, Francjan J; Fokkema, Margaretha

UNLABELLED: In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early

PKU: High plasma phenylalanine concentrations are associated with increased prevalence of mood swings

NARCIS (Netherlands)

Anjema, K.; Rijn, M. van; Verkerk, P.H.; Burgerhof, J.G.M.; Heiner-Fokkema, M.R.; Spronsen, F.J. van

2011-01-01

In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early treated PKU

Phenylketonuria : tyrosine supplementation in phenylalanine-restricted diets

NARCIS (Netherlands)

van Spronsen, FJ; van Rijn, M; Bekhof, J; Koch, R; Smit, PGA

Treatment of phenylketonuria (PKU) consists of restriction of natural protein and provision of a protein substitute that lacks phenylalanine but is enriched in tyrosine. Large and unexplained differences exist, however, in the tyrosine enrichment of the protein substitutes. Furthermore, some

Respiratory ammonia output and blood ammonia concentration during incremental exercise

NARCIS (Netherlands)

Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

Formation of tyrosine isomers in aqueous phenylalanine solutions by gamma irradiation

International Nuclear Information System (INIS)

Aflaki, F.; Salahinejad, M.; Roozbehani, A.

2009-01-01

Ortho-tyrosine detection method can be used for detection of irradiated protein rich foods. Tyrosine isomers produced by gamma radiation of aqueous phenylalanine solutions at wide dose levels (0.1-50 k Gy) were examined to obtain basic information for o-tyrosine detection method of irradiated foods. Determination of tyrosines produced in aqueous phenylalanine solutions were carried out by high performance liquid chromatography and fluorescence detection. The detection limit of o-tyrosine was 0.01 ppm and the linear range of calibration and the relative standard deviation of analysis was 50 ng and 4-13%, respectively. The amounts of the tyrosines increased with the irradiation level up to 10 k Gy and no further tyrosine formation was observed when the dose level was increased. At a constant dose level, the yield of tyrosines initially increased with the phenylalanine concentration, while with further increase of phenylalanine concentration no effect on increase of tyrosine yield was observed. When the dose rate was varying from 2.3 k Gy/h to 1.2 k Gy/h with a total amount of 10 k Gy in each case, there was no significant effect on tyrosine isomers formation was observed. Also the results showed that tyrosine yield was affected by temperature, p H and the presence of oxygen

Doxycycline hinders phenylalanine fibril assemblies revealing a potential novel therapeutic approach in phenylketonuria.

Science.gov (United States)

De Luigi, Ada; Mariani, Alessandro; De Paola, Massimiliano; Re Depaolini, Andrea; Colombo, Laura; Russo, Luca; Rondelli, Valeria; Brocca, Paola; Adler-Abramovich, Lihi; Gazit, Ehud; Del Favero, Elena; Cantù, Laura; Salmona, Mario

2015-10-29

A new paradigm for the aetiopathology of phenylketonuria suggests the presence of amyloid-like assemblies in the brains of transgenic mouse models and patients with phenylketonuria, possibly shedding light on the selective cognitive deficit associated with this disease. Paralleling the amyloidogenic route that identifies different stages of peptide aggregation, corresponding to different levels of toxicity, we experimentally address for the first time, the physico-chemical properties of phenylalanine aggregates via Small Angle, Wide Angle X-ray Scattering and Atomic Force Microscopy. Results are consistent with the presence of well-structured, aligned fibres generated by milliMolar concentrations of phenylalanine. Moreover, the amyloid-modulating doxycycline agent affects the local structure of phenylalanine aggregates, preventing the formation of well-ordered crystalline structures. Phenylalanine assemblies prove toxic in vitro to immortalized cell lines and primary neuronal cells. Furthermore, these assemblies also cause dendritic sprouting alterations and synaptic protein impairment in neurons. Doxycycline counteracts these toxic effects, suggesting an approach for the development of future innovative non-dietary preventive therapies.

Ammonia complexes of metals in aqueous solutions with high concentrations of ammonia

International Nuclear Information System (INIS)

Padar, T.G.; Novikov, L.K.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

1991-01-01

Potentiometric method, glass electrodes and Bierrum function were used to study the formation of ammonia complexes of magnesium, calcium, cadmium, zinc, copper(2) and silver in 2.0 mol/dm 3 aqueous solutions of ammonia nitrate with 0-18 mol/dm 3 ammonia concentrations at 25.0 deg C. Step constants of stability of studied complexes were calculated and their compositions were determined with account of nonideal character of aqueous-salt solutions with ammonia concentrations above 1.0 mol/dm 3 . Values of correction effects on salting out ammonia action for Bierrum function in solutions with 1.0-18 mol/dm 3 ammonia concentrations were found

Phenylalanine Removal from Water by Fe3O4 Nanoparticles Functionalized with Two Different Surfactants

Directory of Open Access Journals (Sweden)

Ameneh Heidari

2016-07-01

Full Text Available In the present study, the application for the removal of phenylalanine by using two nano sorbents, namely, cetyltrimethylammonium bromide –Coated and BKC (benzal-conium chloride-Coated Fe3O4 nanoparticles was investigated. Solid-phase extraction (SPE and ultra violet–visible spectroscopy were used for studying the removal ability of each nano-sorbent in this study. Scanning Electron Microscopy, X-ray diffraction and Fourier infrared were used to characterize the synthesized magnetite nanoparticles. Batch adsorption studies were carried out to study the effect of various parameters, such as contact time, solution pH and concentration of phenylalanine. The equilibrium adsorption data of phenylalanine onto Fe3O4 nanoparticles (non-functionalized sample, cetyltrimethylammonium bromide -Coated and BKC -Coated were analyzed using Freundlich and Langmuir adsorption isotherms. The results indicated that adsorption of phenylalanine increased with increasing solution pH and maximum removal of phenylalanine was obtained at pH=9.0. Correlation coefficient were determined by analyzing each isotherm. It was found that the Freundlich equation showed better correlation with the experimental data than the Langmuir.

Racemization of aspartic acid and phenylalanine in the sweetener aspartame at 100 degrees C.

Science.gov (United States)

Boehm, M F; Bada, J L

1984-01-01

The racemization half-lives (i.e., the time required to reach a D/L = 0.33) at pH 6.8 for aspartic acid and phenylalanine in the sweetener aspartame (L-aspartyl-L-phenylalanine methyl ester) were determined to be 13 and 23 hours, respectively, at 100 degrees C. Racemization at this pH does not occur in aspartame but rather in its diketopiperazine decomposition product. Our results indicate that the use of aspartame to sweeten neutral pH foods and beverages that are then heated at elevated temperature could generate D-aspartic acid and D-phenylalanine. The nutritive consequences of these D-amino acids in the human diet are not well established, and thus aspartame should probably not be used as a sweetener when the exposure of neutral pH foods and beverages to elevated temperatures is required. At pH 4, a typical pH of most foods and beverages that might be sweetened with aspartame, the half-lives are 47 hours for aspartic acid and 1200 hours for phenylalanine at 100 degrees C. Racemization at pH 4 takes place in aspartame itself. Although the racemization rates at pH 4 are slow and no appreciable racemization of aspartic acid and phenylalanine should occur during the normal use of aspartame, some food and beverage components could conceivably act as catalysts. Additional studies are required to evaluate whether the use of aspartame as a sugar substitute might not in turn result in an increased human consumption of D-aspartic acid and D-phenylalanine. PMID:6591191

Nuclear magnetic resonance studies of phenylalanine analog interactions with normal and sicklen hemoglobin

International Nuclear Information System (INIS)

Lee, Y.H.

1985-01-01

Several phenylalanine derivatives have been found to inhibit the gelation of deoxygenated sickle hemoglobin (deoxy HbS). Proton and 19 F-NMR techniques were used to monitor the interaction of selected phenylalanine derivatives with the Hb molecule by using fluorine containing phenylalanine derivatives, Hb labeled at the β93 position with N-(2,2,2-trifluoroethyl) iodoacetamide (IA-F 3 ), and by monitoring the relaxation rates of the C2 and C4 histidine protons. The results show that the 19 F spin-spin relaxation times of L-phenylalanin-4-fluorobenzylamide (PheNBz1-F), which has a deoxy HbS antigelling activity comparable to that of the amino acid, tryptophan, are affected much more strongly by interaction with Hb than are those of glycin-4-fluorobenzylamide (GlyNBz1-F). In contrast, it is shown that N-(2,2,5,5-tetramethylpyrrolidin-1-oxy-3-carboxyl)-L-phenylalanine t-butyl ester (SL-Phe) exhibits specific binding to Hb, and an antigelling activity more than two orders of magnitude greater than that of phenylalanine. These results indicate that the fluorine nuclei strongly influenced by the presence of spin label nitroxide are located in a conformation within a few angstroms of the SL-Phe binding site. Proton NMR relaxation measurements of the C2 and C4 proton resonances from the β2, 4b143 and β146 histidine residues show significant and selective effects from the binding of SL-Phe to Hb, indicating that the SL-Phe binding site must be close to the side chains of these three residues. The strong antigelation activity of SL-Phe suggests that this binding site may be one of the intermolecular contact sites of importance to the deoxy HbS aggregation process

Phenylalanine-a biogenic ligand with flexible η6- and η6:κ1-coordination at ruthenium(ii) centres

KAUST Repository

Reiner, Thomas; Jantke, Dominik; Miao, Xiaohe; Marziale, Alexander N.; Kiefer, Florian J.; Eppinger, Jö rg

2013-01-01

The reaction of (S)-2,5-dihydrophenylalanine 1 with ruthenium(iii) chloride yields the μ-chloro-bridged dimeric η6-phenylalanine ethyl ester complex 3, which can be converted into the monomeric analogue, η6:κ1-phenylalanine ethyl ester complex 12, under basic conditions. Studies were carried out to determine the stability and reactivity of complexes bearing η6- and η6: κ1-chelating phenylalanine ligands under various conditions. Reaction of 3 with ethylenediamine derivatives N-p-tosylethylenediamine or 1,4-di-N-p-tosylethylenediamine results in the formation of monomeric η6:κ1-phenylalanine ethyl ester complexes 14 and 15, which could be saponified yielding complexes 16 and 17 without changing the inner coordination sphere of the metal centre. The structure of η6:κ1-phenylalanine complex 17 and an N-κ1-phenylalanine complex 13 resulting from the reaction of 3 with an excess of pyridine were confirmed by X-ray crystallography. © 2013 The Royal Society of Chemistry.

Analog kefir production with a low phenylalanine for Phenylketonuria

Directory of Open Access Journals (Sweden)

Amir Yari

2017-06-01

Full Text Available Phenylketonuria (PKU is one of the most prevalent types of hereditary metabolic disorders which is caused due to an absence or reduction of the activity of the Phenylalanine hydroxylase enzyme in the liver which in turn, inhibits the transformation of phenylalanine (Phe to tyrosine. In clinical terms, this disorder is displayed with severe, permanent and irreversible mental retardation. This research was aimed at development of a highly nutrient and acceptable suitable analogue Kefir drink for these patients. The mentioned drink is based on milk permeate, cream powder and includes glycomacropeptide (GMP as a source of protein, starter as a fermentation source, the trance glutamines (TG enzyme, dough stabilizer and modified corn starch as tissue maker, salt and water. The GMP used in this analogue drink is intended for enrichment of the product and therefore it was added by 3% to one formula. The aforementioned sample had a lower calculated amount of pH and alcohol percentage in comparison with the 16 samples which did not have GMP. The results of this study showed that the analog kefir has a low level of phenylalanine (30.40 mg/100g and in that regard, it can be considered to be useful for patients with PKU.

New LASER fluorometric HPLC detection for ortho-tyrosine in gamma-irradiated phenylalanine solution and pork

International Nuclear Information System (INIS)

Miyahara, Makoto; Toyoda, Masatake; Saito, Yukio; Nagasawa, Taeko; Izumi, Keiko; Kitamura, Mayumi

1999-01-01

New analytical procedure for o-tyrosine was studied to investigate effects of gamma irradiation on aqueous phenylalanine solution and pork. The process includes extraction and hydrolysis of protein, derivatization of the free amino acid by fluororeagent, and finally separation and detection by LASER fluorometric HPLC. The detection limit was 25ng. To study how the procedure works, irradiated phenylalanine solution and pork were analyzed. The samples were irradiated at doses up to 10 kGy at room temperature. Three tyrosine isomers were detected in phenylalanine solution, and 2 isomers (o-and p-tyrosine) were found in pork. Dose response was found in the formation of the isomers both in phenylalanine solution and in pork. O-tyrosine peak obtained from irradiated pork was separated from interference successfully. Those findings illustrate the procedure may be applicable to detection of irradiated food. (author)

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

Science.gov (United States)

Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

The effect of experimental diabetes on phenylalanine metabolism in isolated liver cells.

OpenAIRE

Santana, M A; Fisher, M J; Bate, A J; Pogson, C I

1985-01-01

Chronic (10-day) diabetes was associated with increased metabolic flux through phenylalanine hydroxylase in isolated liver cells. This flux was stimulated by 0.1 microM-glucagon, but not by 10 microM-noradrenaline; 0.1 microM-insulin affected neither basal nor glucagon-stimulated flux. The increased rate of phenylalanine hydroxylation in diabetes was accompanied by parallel increases in enzyme activity (as measured with artificial cofactor) and immunoreactive-enzyme-protein content. In contra...

Ammonia chemistry at SMART

International Nuclear Information System (INIS)

Na, J. W.; Seong, G. W.; Lee, E. H.; Kim, W. C.; Choi, B. S.; Kim, J. P.; Lee, D. J.

1999-01-01

Ammonia is used as the pH control agent of primary water at SMART (System-integrated Modular Advanced ReacTor). Some of this ammonia is decomposed to hydrogen and nitrogen by radiation in the reactor core. The produced hydrogen gas is used for the removal of dissolved oxygen in the coolant. Some of nitrogen gas in pressurizer is dissolved into the primary water. Because ammonia, hydrogen and nitrogen which is produced by ammonia radiolysis are exist in the coolant at SMART, ammonia chemistry at SMART is different with lithium-boron chemistry at commercial PWR. In this study, the pH characteristics of ammonia and the solubility characteristics of hydrogen and nytrogen were analyzed for the management of primary water chemistry at SMART

Mapping the functional landscape of frequent phenylalanine hydroxylase (PAH) genotypes promotes personalised medicine in phenylketonuria.

Science.gov (United States)

Danecka, Marta K; Woidy, Mathias; Zschocke, Johannes; Feillet, François; Muntau, Ania C; Gersting, Søren W

2015-03-01

In phenylketonuria, genetic heterogeneity, frequent compound heterozygosity, and the lack of functional data for phenylalanine hydroxylase genotypes hamper reliable phenotype prediction and individualised treatment. A literature search revealed 690 different phenylalanine hydroxylase genotypes in 3066 phenylketonuria patients from Europe and the Middle East. We determined phenylalanine hydroxylase function of 30 frequent homozygous and compound heterozygous genotypes covering 55% of the study population, generated activity landscapes, and assessed the phenylalanine hydroxylase working range in the metabolic (phenylalanine) and therapeutic (tetrahydrobiopterin) space. Shared patterns in genotype-specific functional landscapes were linked to biochemical and pharmacological phenotypes, where (1) residual activity below 3.5% was associated with classical phenylketonuria unresponsive to pharmacological treatment; (2) lack of defined peak activity induced loss of response to tetrahydrobiopterin; (3) a higher cofactor need was linked to inconsistent clinical phenotypes and low rates of tetrahydrobiopterin response; and (4) residual activity above 5%, a defined peak of activity, and a normal cofactor need were associated with pharmacologically treatable mild phenotypes. In addition, we provide a web application for retrieving country-specific information on genotypes and genotype-specific phenylalanine hydroxylase function that warrants continuous extension, updates, and research on demand. The combination of genotype-specific functional analyses with biochemical, clinical, and therapeutic data of individual patients may serve as a powerful tool to enable phenotype prediction and to establish personalised medicine strategies for dietary regimens and pharmacological treatment in phenylketonuria. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Hydrogen recombiner catalyst test supporting data

International Nuclear Information System (INIS)

Britton, M.D.

1995-01-01

This is a data package supporting the Hydrogen Recombiner Catalyst Performance and Carbon Monoxide Sorption Capacity Test Report, WHC-SD-WM-TRP-211, Rev 0. This report contains 10 appendices which consist of the following: Mass spectrometer analysis reports: HRC samples 93-001 through 93-157; Gas spectrometry analysis reports: HRC samples 93-141 through 93-658; Mass spectrometer procedure PNL-MA-299 ALO-284; Alternate analytical method for ammonia and water vapor; Sample log sheets; Job Safety analysis; Certificate of mixture analysis for feed gases; Flow controller calibration check; Westinghouse Standards Laboratory report on Bois flow calibrator; and Sorption capacity test data, tables, and graphs

Liberation of ammonia by cyanobacteria

Energy Technology Data Exchange (ETDEWEB)

Newton, J.W.

1986-04-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog /sup 14/C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism.

Liberation of ammonia by cyanobacteria

International Nuclear Information System (INIS)

Newton, J.W.

1986-01-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog 14 C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

Science.gov (United States)

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2016-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

Influence of anoxia on the induction of mutations by phenylalanine radicals during gamma-irradiation of plasmid DNA in aqueous solution.

Science.gov (United States)

Kuipers, Gitta K; Slotman, Ben J; Reitsma-Wijker, Carola A; van Andel, Rob J; Poldervaart, Hester A; Lafleur, M Vincent M

2004-12-21

When DNA is irradiated in aqueous solution, most of the damage is inflicted by water-derived radicals. This is called the indirect effect of ionizing radiation. However in whole cells not only the primary formed water radicals play a role, because some cellular compounds form secondary radicals which can also damage DNA. It is known that the amino acid phenylalanine is able to react with water radicals, resulting in the production of secondary phenylalanine radicals which can damage and inactivate DNA. In a previous study the influence of the presence of phenylalanine during gamma-irradiation of DNA in aqueous solution under oxic conditions was studied. Under anoxic irradiation conditions different amounts and types of reactive water-derived radicals are formed compared to oxic conditions and also different phenylalanine radicals are formed. Therefore, this study examines the influence of the presence of phenylalanine under anoxic conditions on the gamma-radiation-induced mutation spectrum. The results indicate that phenylalanine radicals are damaging to DNA, but less effective compared to primary water radicals. On the mutational level, in the presence of phenylalanine radicals under anoxic conditions, the amount of mutations on G:C base pairs was significantly decreased as compared to oxic conditions. Furthermore, the results of this study indicate that nucleotide excision repair is involved in repair of both inactivating and mutagenic damage induced by phenylalanine radicals under anoxic conditions.

Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma.

Science.gov (United States)

Gao, Na; Zhu, Limei; Guo, Zhiqiang; Yi, Meisheng; Zhang, Li

2017-06-01

Ammonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l -1  NH 4 Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l -1  NH 4 Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (T Amm ) in the 0.3-1.1 mmol l -1  NH 4 Cl treatments was significantly higher than those in the 0 and 0.1 mmol l -1  NH 4 Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l -1  NH 4 Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l -1  NH 4 Cl treatment. J Amm steadily increased in ambient ammonia from 0 to 0.6 mmol l -1 and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l -1 . Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue T Amm via reducing the ammonia production and increasing ammonia excretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of pH and ADP on ammonia affinity for human glutamate dehydrogenases

DEFF Research Database (Denmark)

Zaganas, Ioannis; Pajecka, Kamilla; Nielsen, Camilla Wendel

2013-01-01

Glutamate dehydrogenase (GDH) uses ammonia to reversibly convert α-ketoglutarate to glutamate using NADP(H) and NAD(H) as cofactors. While GDH in most mammals is encoded by a single GLUD1 gene, humans and other primates have acquired a GLUD2 gene with distinct tissue expression profile. The two...... human isoenzymes (hGDH1 and hGDH2), though highly homologous, differ markedly in their regulatory properties. Here we obtained hGDH1 and hGDH2 in recombinant form and studied their Km for ammonia in the presence of 1.0 mM ADP. The analyses showed that lowering the pH of the buffer (from 8.0 to 7.......0) increased the Km for ammonia substantially (hGDH1: from 12.8 ± 1.4 mM to 57.5 ± 1.6 mM; hGDH2: from 14.7 ± 1.6 mM to 62.2 ± 1.7 mM), thus essentially precluding reductive amination. Moreover, lowering the ADP concentration to 0.1 mM not only increased the K0.5 [NH4 (+)] of hGDH2, but also introduced...

DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

NARCIS (Netherlands)

HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Determination of ammonia in ear-lobe capillary blood is an alternative to arterial blood ammonia

NARCIS (Netherlands)

Huizenga, J. R.; Gips, C. H.; Conn, H. O.; Jansen, P. L.

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Chiral separation of substituted phenylalanine analogues using chiral palladium phosphine complexes with enantioselective liquid-liquid extraction

NARCIS (Netherlands)

Verkuijl, B.J.V.; Schuur, B.; Minnaard, A.J.; Vries, de J.G.; Feringa, B.L.

2010-01-01

Chiral palladium phosphine complexes have been employed in the chiral separation of amino acids and phenylalanine analogues in particular. The use of (S)-xylyl-BINAP as a ligand for the palladium complex in enantioselective liquid–liquid extraction allowed the separation of the phenylalanine

Enzymatic Preparation of Low-Phenylalanine Formula Derived from ...

African Journals Online (AJOL)

Background: Phenylketonuria (PKU) is one of the most common inborn errors of amino acids metabolism. WHO guidelines introduced in 1979 and revised 1988 for breast-feeding infants with PKU included a formula containing low amounts of phenylalanine as a part of dietary prescription. Mental retardation can be ...

Polymorphism and modulation of para-substituted L-Phenylalanine

NARCIS (Netherlands)

Sögütoglu, Leyla-cann; Lutz, Martin; Meekes, Hugo; De Gelder, Rene; Vlieg, Elias

2017-01-01

The crystal structure of para-methyl-L-phenylalanine at 230 K resembles that of the para-fluorinated analogue from the literaturebut is commensurately modulated with seven molecules in the asymmetric unit (Z′ = 7). At 100 K, the superstructure loses its modulation, leading to a unit cell with Z′ =

Enrichment of ammonia concentration from aqua-ammonia vapors by using 3A molecular sieve

International Nuclear Information System (INIS)

Chiou, J.S.; Lin, T.M.; She, K.Y.; Chen, W.M.

2009-01-01

In aqua-ammonia refrigeration systems, the ammonia is the refrigerant and the water is the absorbent, the vapor produced in the generator always contains a small fraction of water. The removed of this residual water is a crucial issue in order to guarantee a reliable and efficient operation of these systems. Currently, the thermal distillation methods (via a rectifier and/or an analyzer) are used to further separate the water from aqua-ammonia mixtures. In this study, a molecular sieve module is used for ammonia purification. A thermal system with a 3A molecular sieve module was set up, and the conditions of working fluid entering into the sieve module is similar to that entering into the rectifier tower of a typical aqua-ammonia absorption system. Results from ammonia enrichment tests indicate the concentration of ammonia can be raised from about 80% up to about 99% if siever installation was properly arranged.

The metabolism of C14-labeled phenylalanine and tyrosine in malaria-infected Culex-females

International Nuclear Information System (INIS)

Maier, W.A.; Nassif-Makki, H.

1975-01-01

Culex females are fed on C14-phenylalanine or C14-tyrosine in sugar solution. Autoradiographic studies on homogenated females 1 or 4 days after feeding, show that the labeled amino acids are metabolized on the first day and are not detectable on the fourth day. After increase of the amino acid concentration by saturation of the sugar solution with the unlabeled amino acid, the labeled acid and its metabolites are visible over a longer period of time. Phenylalanine is metabolized to tyrosine and at least four other substances. Radioactivity on the starting point of the chromatogram can be interpreted as incorporation of tyrosine into proteins. After infection with Plasmodium cathemerium, and feeding of C14-phenylalanine C14-tyrosine is demonstrable over a longer period. (orig.) [de

Results of a Prospective Study Concerning the Clinical Efficiency of Recent Russian-Made Specialized Foods without Phenylalanine

Directory of Open Access Journals (Sweden)

T. V. Bushueva

2016-01-01

Full Text Available Background: Specialized foods, based on aminoacids without phenilalanin, are the main source of protein for patients with phenilketonuria of all ages. Based on modern technologies, new Russian-made foods were created. They have an optimized aminoacid and micronutrient composition, which increases their bioavailability.Objective: Our aim was to investigate the clinical efficiency of the new Russian-made specialized foods based on aminoacids without phenylalanine, in patients with phenylketonuria.Methods: Evaluating physical, somatic and neuropsychic development as well as measuring phenylalanine blood level were carried out twice: before the prescription and after 1 month of using the new Russian-made specialized foods. The chemical composition of the ration was controlled using dietology methods.Results: 57 children at the age of 14 days to 15 years with phenylketonuria (which was detected in neonatal screening were picked for this study. A hypophenylalanine diet has been prescribed for all children no later than at the age of 3 months of life. In children of the first year (I group (among which there were children with high phenylalanine blood levels phenylalanine concentration decreased from 5,5 (4,0; 21,0 to 4,4 (3,7; 4,7 mg/dl (p = 0,014 while using Russian-made specialized foods. In this group of children the psychomotor and physical indices improved. In early childhood-, preschool- and school-aged patients phenylalanine blood level remained steady. The chemical composition of the ration with Russian-made foods, based on aminoacids without phenylalanine, corresponded to the reference intake of main nutrients and energy.Conclusion: Hypophenylalanine diet with new Russian-made specialized foods without phenylalanine (which is designed for phenylketonuria patients of various age groups showed high clinical efficiency of these foods.

Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

(SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g-N/L(CSTR...... performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. In continuous reactor operation, 112% extra biogas production was achieved due to ammonia recovery. High-throughput molecular sequencing analysis showed an impact...... of ammonia recovery on the microbial community composition in the integrated system. Results clearly indicate the great potential of the SMRC-CSTR-coupled system for efficient and cost-effective ammonia recovery, energy production and treatment of ammonia-rich residues....

RESULTS OF INITIAL AMMONIA OXIDATION TESTING

Energy Technology Data Exchange (ETDEWEB)

Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-12-30

This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

OpenAIRE

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2015-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia.

Exergy analysis of industrial ammonia synthesis

International Nuclear Information System (INIS)

Kirova-Yordanova, Zornitza

2004-01-01

Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen-nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called 'ammonia synthesis loop'). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

OpenAIRE

Nakagawa, Tatsunori; Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

Mechanistic, Mutational, and Structural Evaluation of a Taxus Phenylalanine Aminomutase

Energy Technology Data Exchange (ETDEWEB)

Feng, Lei; Wanninayake, Udayanga; Strom, Susan; Geiger, James; Walker, Kevin D. (MSU)

2014-10-02

The structure of a phenylalanine aminomutase (TcPAM) from Taxus canadensis has been determined at 2.4 {angstrom} resolution. The active site of the TcPAM contains the signature 4-methylidene-1H-imidazol-5(4H)-one prosthesis, observed in all catalysts of the class I lyase-like family. This catalyst isomerizes (S)-{alpha}-phenylalanine to the (R)-{beta}-isomer by exchange of the NH{sub 2}/H pair. The stereochemistry of the TcPAM reaction product is opposite of the (S)-{beta}-tyrosine made by the mechanistically related tyrosine aminomutase (SgTAM) from Streptomyces globisporus. Since TcPAM and SgTAM share similar tertiary- and quaternary-structures and have several highly conserved aliphatic residues positioned analogously in their active sites for substrate recognition, the divergent product stereochemistries of these catalysts likely cannot be explained by differences in active site architecture. The active site of the TcPAM structure also is in complex with (E)-cinnamate; the latter functions as both a substrate and an intermediate. To account for the distinct (3R)-{beta}-amino acid stereochemistry catalyzed by TcPAM, the cinnamate skeleton must rotate the C{sub 1}-C{sub {alpha}} and C{sub ipso}-C{sub {beta}} bonds 180{sup o} in the active site prior to exchange and rebinding of the NH{sub 2}/H pair to the cinnamate, an event that is not required for the corresponding acrylate intermediate in the SgTAM reaction. Moreover, the aromatic ring of the intermediate makes only one direct hydrophobic interaction with Leu-104. A L104A mutant of TcPAM demonstrated an 1.5-fold increase in k{sub cat} and a decrease in K{sub M} values for sterically demanding 3'-methyl-{alpha}-phenylalanine and styryl-{alpha}-alanine substrates, compared to the kinetic parameters for TcPAM. These parameters did not change significantly for the mutant with 4'-methyl-{alpha}-phenylalanine compared to those for TcPAM.

Renal Ammonia Metabolism and Transport

Science.gov (United States)

Weiner, I. David; Verlander, Jill W.

2015-01-01

Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4+ and 2 HCO3− for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3−-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4+ trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4+-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K+, and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis. PMID:23720285

Binding of Nickel to Testicular Glutamate–Ammonia Ligase Inhibits Its Enzymatic Activity

Science.gov (United States)

SUN, YINGBIAO; OU, YOUNG; CHENG, MIN; RUAN, YIBING; VAN DER HOORN, FRANS A.

2016-01-01

SUMMARY Exposure to nickel has been shown to cause damage to the testis in several animal models. It is not known if the testis expresses protein(s) that can bind nickel. To test this, we used a nickel-binding assay to isolate testicular nickel-binding proteins. We identified glutamate–ammonia ligase (GLUL) as a prominent nickel-binding protein by mass spectrometry. Protein analysis and reverse transcriptase polymerase chain reaction showed that GLUL is expressed in the testis, predominantly in interstitial cells. We determined that GLUL has a higher affinity for nickel than for its regular co-factor manganese. We produced an enzymatically active, recombinant GLUL protein. Upon binding, nickel interferes with the manganese-catalyzed enzymatic activity of recombinant GLUL protein. We also determined that GLUL activity in testes of animals exposed to nickel sulfate is reduced. Our results identify testicular GLUL as the first testicular protein shown to be affected by nickel exposure. PMID:21254280

Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

Science.gov (United States)

Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

2004-11-01

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

Ammonia toxicity: from head to toe?

Science.gov (United States)

Dasarathy, Srinivasan; Mookerjee, Rajeshwar P; Rackayova, Veronika; Rangroo Thrane, Vinita; Vairappan, Balasubramaniyan; Ott, Peter; Rose, Christopher F

2017-04-01

Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurological impairment. However, the deleterious effects of ammonia are not specific to the brain, as the direct effect of increased ammonia (change in pH, membrane potential, metabolism) can occur in any type of cell. Therefore, in the setting of chronic liver disease where multi-organ dysfunction is common, the role of ammonia, only as neurotoxin, is challenged. This review provides insights and evidence that increased ammonia can disturb many organ and cell types and hence lead to dysfunction.

Quantitation of deuterated and non-deuterated phenylalanine and tyrosine in human plasma using the selective ion monitoring method with combined gas chromatography-mass spectrometry

International Nuclear Information System (INIS)

Zagalak, M.-J.; Curtius, H.-Ch.; Leimbacher, W.; Redweik, U.

1977-01-01

A specific method is described for the quantitative analysis of deutarated and non-deuterated phenylalanine and tyrosine in human plasma by gas chromatography-mass spectrometry using selective ion monitoring. From the several derivatives investigated, the N- or N,O-trifluoroacetyl methyl esters were found to be the most suitable for our purposes. DL-Phenylalanine-4-d 1 and L-tyrosine-d 7 were used as internal standards. The sensitivity of this method permits the measurement of amounts as small as ca. 2.5 ng/ml in plasma for both phenylalanine and tyrosine. The coefficients of variation were found to be ca. 1.6% (n=12) for phenylalanine and 3.0% (n=12) for tyrosine. Using this method, an in vivo determination of phenylalanine-4-monooxygenase activity in humans is possible by loading the subjects with deuterated L-phenylalanine-d 5 (accepted as substrate by phenylalanine-4-monooxygenase E.C. 1.14.16.1) and the subsequent measuring of deuterated L-tyrosine-d 4 formed and residual L-phenylalanine-d 5

Ammonia Leak Locator Study

Science.gov (United States)

Dodge, Franklin T.; Wuest, Martin P.; Deffenbaugh, Danny M.

1995-01-01

The thermal control system of International Space Station Alpha will use liquid ammonia as the heat exchange fluid. It is expected that small leaks (of the order perhaps of one pound of ammonia per day) may develop in the lines transporting the ammonia to the various facilities as well as in the heat exchange equipment. Such leaks must be detected and located before the supply of ammonia becomes critically low. For that reason, NASA-JSC has a program underway to evaluate instruments that can detect and locate ultra-small concentrations of ammonia in a high vacuum environment. To be useful, the instrument must be portable and small enough that an astronaut can easily handle it during extravehicular activity. An additional complication in the design of the instrument is that the environment immediately surrounding ISSA will contain small concentrations of many other gases from venting of onboard experiments as well as from other kinds of leaks. These other vapors include water, cabin air, CO2, CO, argon, N2, and ethylene glycol. Altogether, this local environment might have a pressure of the order of 10(exp -7) to 10(exp -6) torr. Southwest Research Institute (SwRI) was contracted by NASA-JSC to provide support to NASA-JSC and its prime contractors in evaluating ammonia-location instruments and to make a preliminary trade study of the advantages and limitations of potential instruments. The present effort builds upon an earlier SwRI study to evaluate ammonia leak detection instruments [Jolly and Deffenbaugh]. The objectives of the present effort include: (1) Estimate the characteristics of representative ammonia leaks; (2) Evaluate the baseline instrument in the light of the estimated ammonia leak characteristics; (3) Propose alternative instrument concepts; and (4) Conduct a trade study of the proposed alternative concepts and recommend promising instruments. The baseline leak-location instrument selected by NASA-JSC was an ion gauge.

Enhancement of L-phenylalanine production by engineered Escherichia coli using phased exponential L-tyrosine feeding combined with nitrogen source optimization.

Science.gov (United States)

Yuan, Peipei; Cao, Weijia; Wang, Zhen; Chen, Kequan; Li, Yan; Ouyang, Pingkai

2015-07-01

Nitrogen source optimization combined with phased exponential L-tyrosine feeding was employed to enhance L-phenylalanine production by a tyrosine-auxotroph strain, Escherichia coli YP1617. The absence of (NH4)2SO4, the use of corn steep powder and yeast extract as composite organic nitrogen source were more suitable for cell growth and L-phenylalanine production. Moreover, the optimal initial L-tyrosine level was 0.3 g L(-1) and exponential L-tyrosine feeding slightly improved L-phenylalanine production. Nerveless, L-phenylalanine production was greatly enhanced by a strategy of phased exponential L-tyrosine feeding, where exponential feeding was started at the set specific growth rate of 0.08, 0.05, and 0.02 h(-1) after 12, 32, and 52 h, respectively. Compared with exponential L-tyrosine feeding at the set specific growth rate of 0.08 h(-1), the developed strategy obtained a 15.33% increase in L-phenylalanine production (L-phenylalanine of 56.20 g L(-1)) and a 45.28% decrease in L-tyrosine supplementation. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU

NARCIS (Netherlands)

Spronsen, F.J. van; Rijn, M.; Dorgelo, B.; Hoeksma, M.; Bosch, A.M.; Mulder, M.F.; Klerk, J.B.C. de; Koning, T. de; Rubio-Gozalbo, M.E.; Vries, M. de; Verkerk, P.H.

2009-01-01

Background: The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe

Rectal administration of 13N-ammonia in the study of ammonia metabolism

International Nuclear Information System (INIS)

Koen, Hirofumi

1980-01-01

13 N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed 13 N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; 13 N-activity over the head was also recorded. Sequential changes of 13 N-activity in blood was measured, and chromatographic analysis of 13 N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, 13 N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of 13 N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. 13 N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed 13 N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of 13 N and 13 N over the head were closely correlated with various indices of portal hypertension. The relative proportion of 13 N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia. (author)

Ammonia Emissions from Agriculture in China

Science.gov (United States)

Chen, Y.; Zhang, L.; Zhao, Y.; Huang, B.

2016-12-01

Ammonia (NH3) is an important alkaline pollutant in the atmosphere and it has various environmental and climatic effects. We will present an improved bottom-up estimate of ammonia emissions from agriculture in China at 0.5°×0.5° horizontal resolution and monthly variability. Ammonia emissions from fertilizer use are derived using data of crop planting area, fertilizer application time and rate for 18 main crops. Ammonia emission factors from fertilizer use are estimated as a function of soil properties such as soil pH, cation exchange capacity (CEC), and agricultural activity information such as crop type, fertilizer type, and application mode. We further consider ambient temperature and wind speed to account for the meteorological influences on ammonia emission factors of fertilizer use. We also estimate the ammonia emission from livestock over China using the mass-flow methodology. The derived ammonia emissions in China for the year 2005 are 4.55 Tg NH3 from fertilizer use and 6.96 Tg from livestock. Henan and Jiangsu provinces are the two largest emitting areas for ammonia from fertilizer use (470 Gg NH3 and 365 Gg NH3). Henan (621 Gg NH3) and Shandong (533 Gg NH3) have the largest ammonia emissions from livestock. Both ammonia emissions from fertilizer use and livestock have distinct seasonal variations; peaking in June for fertilizer use (822 Gg NH3) and in July for livestock (1244 Gg NH3), and are both lowest in January (80 Gg and 241 Gg, respectively). Combining with other ammonia source (eg. human waste and transport) estimates from the REAS v2.1 emission inventory, we show that total ammonia emissions in China for the year 2005 are 14.0 Tg NH3 a-1. Comparisons with satellite measurements of ammonia columns will also be presented.

Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

Science.gov (United States)

Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

2004-10-01

In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

Plasma phenylalanine and tyrosine responses to different nutritional conditions (fasting/postprandial) in patients with phenylketonuria: effect of sample timing.

Science.gov (United States)

van Spronsen, F J; van Rijn, M; van Dijk, T; Smit, G P; Reijngoud, D J; Berger, R; Heymans, H S

1993-10-01

To evaluate the adequacy of dietary treatment in patients with phenylketonuria, the monitoring of plasma phenylalanine and tyrosine concentrations is of great importance. The preferable time of blood sampling in relation to the nutritional condition during the day, however, is not known. It was the aim of this study to define guidelines for the timing of blood sampling with a minimal burden for the patient. Plasma concentrations of phenylalanine and tyrosine were measured in nine patients with phenylketonuria who had no clinical evidence of tyrosine deficiency. These values were measured during the day both after a prolonged overnight fast, and before and after breakfast. Phenylalanine showed a small rise during prolonged fasting, while tyrosine decreased slightly. After an individually tailored breakfast, phenylalanine remained stable, while tyrosine showed large fluctuations. It is concluded that the patient's nutritional condition (fasting/postprandial) is not important in the evaluation of the phenylalanine intake. To detect a possible tyrosine deficiency, however, a single blood sample is not sufficient and a combination of a preprandial and postprandial blood sample on the same day is advocated.

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU

NARCIS (Netherlands)

van Spronsen, F. J.; van Rijn, M.; Dorgelo, B.; Hoeksma, M.; Bosch, A. M.; Mulder, M. F.; de Klerk, J. B. C.; de Koning, T.; Rubio-Gozalbo, M. Estela; de Vries, M.; Verkerk, P. H.

The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early

Phenylalanine tolerance can already reliably be assessed at the age of 2 years in patients with PKU

NARCIS (Netherlands)

van Spronsen, F. J.; van Rijn, M. [=Margreet; Dorgelo, B.; Hoeksma, M.; Bosch, A. M.; Mulder, M. F.; de Klerk, J. B. C.; de Koning, T.; Rubio-Gozalbo, M. Estela; de Vries, M.; Verkerk, P. H.

2009-01-01

The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early

Fifteen-year follow-up of pulmonary function in individuals heterozygous for the cystic fibrosis phenylalanine-508 deletion

DEFF Research Database (Denmark)

Dahl, Morten; Nordestgaard, B G; Lange, P

2001-01-01

In a cross-sectional study, we previously showed that cystic fibrosis phenylalanine-508 deletion (DeltaF508) heterozygosity may be overrepresented among individuals with asthma.......In a cross-sectional study, we previously showed that cystic fibrosis phenylalanine-508 deletion (DeltaF508) heterozygosity may be overrepresented among individuals with asthma....

Phenylketonuria: translating research into novel therapies

Science.gov (United States)

Ho, Gladys

2014-01-01

Phenylketonuria (PKU) is an inborn error of metabolism of the amino acid phenylalanine. It is an autosomal recessive disorder with a rate of incidence of 1 in 10,000 in Caucasian populations. Mutations in the phenylalanine hydroxylase (PAH) gene are the major cause of PKU, due to the loss of the catalytic activity of the enzyme product PAH. Newborn screening for PKU allows early intervention, avoiding irreparable neurological damage and intellectual disability that would arise from untreated PKU. The current primary treatment of PKU is the limitation of dietary protein intake, which in the long term may be associated with poor compliance in some cases and other health problems due to malnutrition. The only alternative therapy currently approved is the supplementation of BH4, the requisite co-factor of PAH, in the orally-available form of sapropterin dihydrochloride. This treatment is not universally available, and is only effective for a proportion (estimated 30%) of PKU patients. Research into novel therapies for PKU has taken many different approaches to address the lack of PAH activity at the core of this disorder: enzyme replacement via virus-mediated gene transfer, transplantation of donor liver and recombinant PAH protein, enzyme substitution using phenylalanine ammonia lyase (PAL) to provide an alternative pathway for the metabolism of phenylalanine, and restoration of native PAH activity using chemical chaperones and nonsense read-through agents. It is hoped that continuing efforts into these studies will translate into a significant improvement in the physical outcome, as well as quality of life, for patients with PKU. PMID:26835324

Shape Memory Properties and Enzymatic Degradability of Poly(ε-caprolactone)-Based Polyurethane Urea Containing Phenylalanine-Derived Chain Extender.

Science.gov (United States)

Wang, Rong; Zhang, Fanjun; Lin, Weiwei; Liu, Wenkai; Li, Jiehua; Luo, Feng; Wang, Yaning; Tan, Hong

2018-04-24

Biodegradable shape memory polymers are promising biomaterials for minimally invasive surgical procedures. Herein, a series of linear biodegradable shape memory poly(ε-caprolactone) (PCL)-based polyurethane ureas (PUUs) containing a novel phenylalanine-derived chain extender is synthesized. The phenylalanine-derived chain extender, phenylalanine-hexamethylenediamine-phenylalanine (PHP), contains two chymotrypsin cleaving sites to enhance the enzymatic degradation of PUUs. The degradation rate, the crystallinity, and mechanical properties of PUUs are tailored by the content of PHP. Meanwhile, semicrystalline PCL is not only hydrolytically degradable but also vital for shape memory. Good shape memory ability under body temperature is achieved for PUUs due to the strong interactions in hard segments for permanent crosslinking and the crystallization-melt transition of PCL to switch temporary shape. The PUUs would have a great potential in application as implanting stent. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of ammonia using sodium melt.

Science.gov (United States)

Kawamura, Fumio; Taniguchi, Takashi

2017-09-14

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO 2 . Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO 2 . To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although several catalysts and novel ammonia synthesis methods have been developed previously, expensive materials or low conversion efficiency have prevented the displacement of the Haber-Bosch process. Herein, we present novel ammonia synthesis route using a Na-melt as a catalyst. Using this route, ammonia can be synthesized using a simple process in which H 2 -N 2 mixed gas passes through the Na-melt at 500-590 °C under atmospheric pressure. Nitrogen molecules dissociated by reaction with sodium then react with hydrogen, resulting in the formation of ammonia. Because of the high catalytic efficiency and low-cost of this molten-Na catalyst, it provides new opportunities for the inexpensive synthesis of ammonia and the utilization of ammonia as an energy carrier and next generation fuel.

21 CFR 862.1065 - Ammonia test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ammonia test system. 862.1065 Section 862.1065....1065 Ammonia test system. (a) Identification. An ammonia test system is a device intended to measure ammonia levels in blood, serum, and plasma, Ammonia measurements are used in the diagnosis and treatment...

Browse Title Index

African Journals Online (AJOL)

Items 101 - 150 of 1010 ... Vol 26, No 1 (2018), Characterisation of Phaseolus coccineus interspecific germplasm accessions for disease resistance, grain market class and ... Vol 20, No 2 (2012), Comparative activities of phenylalanine ammonia-lyase and tyrosine ammonia-lyase and phenolic compounds accumulated in ...

Antihypertension and anti-cardiovascular remodeling by phenylalanine in spontaneously hypertensive rats: effectiveness and mechanisms.

Science.gov (United States)

Zhao, G; Li, Z; Gu, T

2001-03-01

To investigate mechanisms of anti-hypertension and anti-cardiovascular remodeling by phenylalanine (phe) in spontaneously hypertensive rats (SHRs). The comparison of blood pressure (BP) increment with the ages and cardiovascular changes of SHRs was made between the 3% phe-intervented group (SHR-phe) and the control SHRs group. Detection of the structural changes with the VIDAS digital vedio-frequency processing technique and light and electron microscopy were made. The cell growth and proliferation of cultured smooth muscle cells (CSMCs) of the thoracic aortas or myocardial fibroblasts were evaluated by measuring the 3H-thymidine counts per minute (cpm) incorporated into the new synthesized desoxyribonucleic acid (DNA) and determining the cell number with the crystal violet stain technique. The Ca2+ influx was measured in counts/min of 45CaCl2 after incubating it with 5 different concentrations of phenylalanine and the intracellular [Ca2+]i by Fura-II/Am indicator. The total messenger ribonucleic acid (mRNA) of the myocardium was extracted and Northern blot analysis was performed with the probe collagen alpha 2 (I) cDNA. The tyrosine hydroxylase (TH) activity was measured by high-performance liquid chromatography (HPLC) with electrochemical detector after having reacted with its substrate tyrosine and other reagents. The catecholamine contents in brain homogenat were detected by HPLC method. The comparison of pharmacokinetics of phenylalanine among SHR-phe, SHRs and control Wistar Kyoto (WKY) rats was made after intravenous injection of 3H-L-phe (1 ml/kg) by PK-GRAPH Program for kinetic calculation. The 3H-L-phe uptake by CSMCs after incubating for definite intervals was also detected and compared. Phenylalanine could prevent the increase of BP with ages and the heart weight (heart/body weight index). The aortic media thickness and the collagen content in the myocardium were decreased significantly in SHR-phe. Whereas the dearranged cardiovascular structure was

Man made disease: clinical manifestations of low phenylalanine levels in an inadequately treated phenylketonuria patient and mouse study.

Science.gov (United States)

Pode-Shakked, Ben; Shemer-Meiri, Lilach; Harmelin, Alon; Stettner, Noa; Brenner, Ori; Abraham, Smadar; Schwartz, Gerard; Anikster, Yair

2013-01-01

Phenylalanine (Phe) deficiency and its clinical manifestations have been previously described mostly as sporadic case reports dating back to the 1960's and 1970's. In these reports, low plasma Phe levels were associated with listlessness, eczematous eruptions and failure to gain weight, most often in infants in their first year of life. Herein we describe a 9 month old female patient with known phenylketonuria, who presented with an unusual constellation of symptoms, including severe erythema and desquamation, alopecia, keratomalacia, corneal perforation, failure to thrive and prolonged diarrhea. The diagnostic possibilities of acrodermatitis enteropathica and vitamin deficiencies were ruled out, and further investigation into her medical history led to the conclusion that during the weeks preceding the hospitalization, the patient's diet consisted of the phenylalanine-free medical formula alone, without the addition of a standard infant formula or food as recommended. Subsequently, dietary control of the blood phenylalanine levels brought swift and marked resolution of the dermatological lesions, with renewal of hair growth. Following this experience, and due to the relative paucity of data regarding the clinical manifestations of low serum phenylalanine levels in humans and their putative pathogenetic mechanisms, we sought to further investigate the effects of a phenylalanine-free diet in a mouse study. For this purpose, twenty mice were randomly allocated to receive either a phenylalanine-deficient diet (n=10) or a normal diet (n=10). Weight was measured weekly, and laboratory tests were obtained including complete blood count, electrolyte studies, and phenylalanine and tyrosine levels. Finally, necropsies and histopathological examinations of different tissues were performed in selected mice, either early after diet initiation, late after diet initiation or following re-introduction of normal diets. The study was then repeated in additional two groups of mice

Aquatic Life Criteria - Ammonia

Science.gov (United States)

Documents related to EPA's final 2013 Aquatic Life Ambient Water Quality Criteria for Ammonia (Freshwater). These documents pertain to the safe levels of Ammonia in water that should protect to the majority of species.

Wastewater Treatment with Ammonia Recovery System

OpenAIRE

M. Örvös; T. Balázs; K. F. Both

2008-01-01

From environmental aspect purification of ammonia containing wastewater is expected. High efficiency ammonia desorption can be done from the water by air on proper temperature. After the desorption process, ammonia can be recovered and used in another technology. The calculation method described below give some methods to find either the minimum column height or ammonia rich solution of the effluent.

Cylinder supplied ammonia scrubber testing in IDMS

International Nuclear Information System (INIS)

Lambert, D.P.

1994-01-01

This report summarizes the results of the off-line testing the Integrated DWPF Melter System (IDMS) ammonia scrubbers using ammonia supplied from cylinders. Three additional tests with ammonia are planned to verify the data collected during off-line testing. Operation of the ammonia scrubber during IDMS SRAT and SME processing will be completed during the next IDMS run. The Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) scrubbers were successful in removing ammonia from the vapor stream to achieve ammonia vapor concentrations far below the 10 ppM vapor exit design basis. In most of the tests, the ammonia concentration in the vapor exit was lower than the detection limit of the analyzers so results are generally reported as <0.05 parts per million (ppM). During SRAT scrubber testing, the ammonia concentration was no higher than 2 ppM and during SME testing the ammonia concentration was no higher than 0.05 m

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Ammonia-based quantum computer

International Nuclear Information System (INIS)

Ferguson, Andrew J.; Cain, Paul A.; Williams, David A.; Briggs, G. Andrew D.

2002-01-01

We propose a scheme for quantum computation using two eigenstates of ammonia or similar molecules. Individual ammonia molecules are confined inside fullerenes and used as two-level qubit systems. Interaction between these ammonia qubits takes place via the electric dipole moments, and in particular we show how a controlled-NOT gate could be implemented. After computation the qubit is measured with a single-electron electrometer sensitive enough to differentiate between the dipole moments of different states. We also discuss a possible implementation based on a quantum cellular automaton

ENGINEERING DESIGN CONFIGURATIONS FOR BIOLOGICAL AMMONIA REMOVAL

Science.gov (United States)

Many regions in the United States have excessive levels of nutrients including ammonia in their source waters. For example, farming and agricultural sources of ammonia in the Midwest contribute to relatively high levels of ammonia in many ground waters. Although ammonia in water ...

Rectal administration of /sup 13/N-ammonia in the study of ammonia metabolism

Energy Technology Data Exchange (ETDEWEB)

Koen, H [Chiba Univ. (Japan). School of Medicine

1980-08-01

/sup 13/N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed /sup 13/N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; /sup 13/N-activity over the head was also recorded. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of /sup 13/N and /sup 13/N over the head were closely correlated with various indices of portal hypertension. The relative proportion of /sup 13/N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia.

Adsorptive molecularly imprinted composite membranes for chiral separation of phenylalanine

Directory of Open Access Journals (Sweden)

Shah Nasrullah

2016-09-01

Full Text Available Two types of composite imprinted membranes, i.e., composite membrane comprised of D-Phe imprinted beads and D-Phe imprinted membrane or DCM and composite membrane comprised of L-Phe imprinted beads and L-Phe imprinted membranes or LCM, were synthesized by phase inversion technique after a uniform dispersion of beads within the polymeric solutions using simple physico-mechanical process. The assemblies of the prepared DCM, LCM and control membranes were employed in ultrafiltration for chiral separation of D, L-Phenylalanine racemate solution. DCM and LCM showed an improved adsorption capacity (0.334 mg g-1 and 0.365 mg g-1 respectively, and adsorption selectivity (2.72 and 2.98 respectively. However, the percent rejection of the template and counter enantiomer were lower than that of control membranes. Compared to control membrane, the DCM and LCM showed inverse permselectivity. These composite membranes having better adsorption and separation ability for Phenylalanine racemate solution will be suitable in the future for various other applications.

Ammonia Synthesis at Low Pressure.

Science.gov (United States)

Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

2017-08-23

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia for hydrogen storage: challenges and opportunities

DEFF Research Database (Denmark)

Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

2008-01-01

The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

Tetraammineplatinum(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pt(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H...N and N—H...Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i32].

Serum phenylalanine in preterm newborns fed different diets of human milk.

Science.gov (United States)

Thomaz, Débora M; Serafin, Paula O; Palhares, Durval B; Tavares, Luciana V M; Grance, Thayana R S

2014-01-01

To evaluate phenylalanine plasma profile in preterm newborns fed different human milk diets. Twenty-four very-low weight preterm newborns were distributed randomly in three groups with different feeding types: Group I: banked human milk plus 5% commercial fortifier with bovine protein, Group II: banked human milk plus evaporated fortifier derived from modified human milk, Group III: banked human milk plus lyophilized fortifier derived from modified human milk. The newborns received the group diet when full diet was attained at 15 ± 2 days. Plasma amino acid analysis was performedon the first and last day of feeding. Comparison among groups was performed by statistical tests: one way ANOVA with Tukey's post-test using SPSS software, version 20.0 (IBM Corp, NY, USA), considering a significance level of 5%. Phenylalanine levels in the first and second analysis were, respectively, in Group I: 11.9 ± 1.22 and 29.72 ± 0.73; in Group II: 11.72 ± 1.04 and 13.44 ± 0.61; and in Group III: 11.3 ± 1.18 and 15.42 ± 0.83 μmol/L. The observed results demonstrated that human milk with fortifiers derived from human milk acted as a good substratum for preterm infant feeding both in the evaporated or the lyophilized form, without significant increases in plasma phenylalanine levels in comparison to human milk with commercial fortifier. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

International Nuclear Information System (INIS)

Sisovic, N. M.; Konjevic, N.

2008-01-01

The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

Effect of template on chiral separation of phenylalanine using molecularly imprinted membrane in aqueous medium

International Nuclear Information System (INIS)

Haq, N.U.

2014-01-01

Wet phase inversion method was used to prepare L-Phenylalanine (L-Phe) and D-Phenylalanine (D-Phe) imprinted poly ((acrylonitrile)-co-(acrylic acid)) membranes for chiral separation. Ultrafiltration experiments were conducted to evaluate the chiral separation ability of the prepared membrane towards racemate aqueous solution of Phenylalanine. The continuous permselectivity was observed by novel membrane. The chiral resolution ability of L-Phe imprinted membrane was much better than that of D-Phe. It was observed that both membranes simultaneously, selectively reject, selectively adsorbed and selectively permeate solute. The achieved adsorption selectivities of L-Phe imprinted membrane (AlphaAds)L and D-Phe imprinted membrane (AlphaAds)D were 2.6 and 2.40 respectively. Permselectivity of L-Phe imprinted membrane (AlphaPerm)L was 2.56 while D-Phe imprinted membrane permselectivity (AlphaPerm)D was 2.03. The rejection selectivities of L-Phe and D-Phe imprinted membranes were (AlphaRej)L=0.32 and (AlphaRej)D =0.28 respectively. (author)

Ammonia as a Suitable Fuel for Fuel Cells

International Nuclear Information System (INIS)

Lan, Rong; Tao, Shanwen

2014-01-01

Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

Tritiated ammonia formation

International Nuclear Information System (INIS)

Heung, L.K.

1995-01-01

When nitrogen was selected as the glovebox atmosphere for the Replacement Tritium Facility (RTF) at the Savannah River Site (SRS), a concern was raised as to the possibility of tritiated ammonia formation in the gloveboxes. Experimental data were produced to study the tritiated ammonia formation rate in a tritium and nitrogen mixture. A rate equation that closely simulates the experimental data was developed. This rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T 2 and N 2 to form NT 3 is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach radiochemical equilibrium dependent on the concentrations of the reactants. 4 refs., 6 figs., 1 tab

The in vivo anti-fibrotic function of calcium sensitive receptor (CaSR) modulating poly(p-dioxanone-co-l-phenylalanine) prodrug.

Science.gov (United States)

Wang, Bing; Wen, Aiping; Feng, Chengmin; Niu, Lijing; Xiao, Xin; Luo, Le; Shen, Chengyi; Zhu, Jiang; Lei, Jun; Zhang, Xiaoming

2018-04-13

In present study, the apoptosis induction and proliferation suppression effects of l-phenylalanine (l-Phe) on fibroblasts were confirmed. The action sites of l-Phe on fibroblasts suppression were deduced to be calcium sensitive receptor (CaSR) which could cause the release of endoplasmic reticulum (ER) Ca 2+ stores; disruption of intracellular Ca 2+ homeostasis triggers cell apoptosis via the ER or mitochondrial pathways. The down-regulation of CaSR were observed after the application of l-Phe, and the results those l-Phe triggered the increasing of intracellular Ca 2+ concentration and calcineurin expression, and then the apoptosis and increasing G1 fraction of fibroblasts have verified our deduction. Hence, l-Phe could be seen as a kind of anti-fibrotic drugs for the crucial participation of fibroblast in the occurrence of fibrosis. And then, poly(p-dioxanone-co-l-phenylalanine) (PDPA) which could prolong the in-vivo anti-fibrotic effect of l-Phe for the sustained release of l-Phe during its degradation could be treated as anti-fibrotic polymer prodrugs. Based on the above, the in vivo anti-fibrotic function of PDPA was evaluated in rabbit ear scarring, rat peritoneum lipopolysaccharide, and rat sidewall defect/cecum abrasion models. PDPA reduced skin scarring and suppressed peritoneal fibrosis and post operation adhesion as well as secretion of transforming growth factor-β1 in injured tissue. These results indicate that PDPA is an effective agent for preventing fibrosis following tissue injury. We have previously demonstrated that poly(p-dioxanone-co-l-phenylalanine) (PDPA) could induce apoptosis to fibroblast and deduced that the inhibitory effect comes from l-phenylalanine. In present study, the inhibition mechanism of l-phenylalanine on fibroblast proliferation was demonstrated. The calcium sensitive receptor (CaSR) was found to be the action site. The CaSR was downregulated after the application of l-phenylalanine, and then the ER Ca 2+ stores were released

(Bio)electrochemical ammonia recovery

NARCIS (Netherlands)

Kuntke, P.; Sleutels, T.H.J.A.; Rodríguez Arredondo, M.; Georg, S.; Barbosa, S.G.; Heijne, Ter A.; Hamelers, Hubertus V.M.; Buisman, C.J.N.

2018-01-01

In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an

Ammonia as a suitable fuel for fuel cells

Directory of Open Access Journals (Sweden)

Rong eLan

2014-08-01

Full Text Available Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

DEFF Research Database (Denmark)

Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...... tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...

Tetraamminepalladium(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pd(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt Pd(enCl2 (en is ethylenediamine and is isotypic with [Pt(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i31]. The Pd2+ cation is coordinated by four ammonia molecules, exhibiting a square-planar geometry. The chloride anions are surrounded by nine ammonia molecules. These are either bound in the palladium complex or solvent molecules. The packing of the ammonia solvent molecules enables the formation of an extended network of N—H...N and N—H...Cl interactions with nearly ideal hydrogen-bonding geometry.

Decreased astrocytic thrombospondin-1 secretion after chronic ammonia treatment reduces the level of synaptic proteins: in vitro and in vivo studies.

Science.gov (United States)

Jayakumar, Arumugam R; Tong, Xiao Y; Curtis, Kevin M; Ruiz-Cordero, Roberto; Shamaladevi, Nagarajarao; Abuzamel, Missa; Johnstone, Joshua; Gaidosh, Gabriel; Rama Rao, Kakulavarapu V; Norenberg, Michael D

2014-11-01

Chronic hepatic encephalopathy (CHE) is a major complication in patients with severe liver disease. Elevated blood and brain ammonia levels have been implicated in its pathogenesis, and astrocytes are the principal neural cells involved in this disorder. Since defective synthesis and release of astrocytic factors have been shown to impair synaptic integrity in other neurological conditions, we examined whether thrombospondin-1 (TSP-1), an astrocytic factor involved in the maintenance of synaptic integrity, is also altered in CHE. Cultured astrocytes were exposed to ammonia (NH₄Cl, 0.5-2.5 mM) for 1-10 days, and TSP-1 content was measured in cell extracts and culture media. Astrocytes exposed to ammonia exhibited a reduction in intra- and extracellular TSP-1 levels. Exposure of cultured neurons to conditioned media from ammonia-treated astrocytes showed a decrease in synaptophysin, PSD95, and synaptotagmin levels. Conditioned media from TSP-1 over-expressing astrocytes that were treated with ammonia, when added to cultured neurons, reversed the decline in synaptic proteins. Recombinant TSP-1 similarly reversed the decrease in synaptic proteins. Metformin, an agent known to increase TSP-1 synthesis in other cell types, also reversed the ammonia-induced TSP-1 reduction. Likewise, we found a significant decline in TSP-1 level in cortical astrocytes, as well as a reduction in synaptophysin content in vivo in a rat model of CHE. These findings suggest that TSP-1 may represent an important therapeutic target for CHE. Defective release of astrocytic factors may impair synaptic integrity in chronic hepatic encephalopathy. We found a reduction in the release of the astrocytic matricellular proteins thrombospondin-1 (TSP-1) in ammonia-treated astrocytes; such reduction was associated with a decrease in synaptic proteins caused by conditioned media from ammonia-treated astrocytes. Exposure of neurons to CM from ammonia-treated astrocytes, in which TSP-1 is over

Dynamic study of ammonia metabolism after rectal administration of /sup 13/N-ammonia

Energy Technology Data Exchange (ETDEWEB)

Koen, H; Arimizu, N; Musha, H; Okuda, K; Tateno, Y [Chiba Univ. (Japan). School of Medicine

1980-01-01

/sup 13/N-ammonia produced by cyclotron, short lived positron emitter (Tl/2 10 min) was instilled intrarectally in a dose of 15 - 30 mCi with liver disease, in order to study the dynamic metabolism of rectally absorbed /sup 13/N-ammonia. A NIRS positron camera connected with an on-line computer system was used for imaging of the liver and heart. /sup 13/N-activity over the head was recorded by detectors used in renography. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was performed using Dowex 50 W x 8. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 - 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group compared with the control. It was suggested that a large proportion of injected /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. We determined the heart/liver activity ratio and this ratio at 15 min was found to be closely correlated with various indices of portal hypertension. The percentages of /sup 13/N-metabolite in blood at 5 min and 15 min were lower in the cirrhotic, suggesting reduced capacity of the liver to remove /sup 13/N-ammonia in cirrhosis.

Catalyst for Ammonia Oxidation

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

Copolyacrylates with phenylalanine and anthracene entities prepared by ATRP and microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Buruiana, E.C., E-mail: emilbur@icmpp.r [Romanian Academy, Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41A, 700487 Iasi (Romania); Murariu, Mioara; Buruiana, Tinca [Romanian Academy, Petru Poni Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41A, 700487 Iasi (Romania)

2010-10-15

In this study, two amino acid copolymers containing anthracene incorporated either on the one end, poly(N-acryloyl-L-phenylalanine-co-methyl methacrylate)-1 or as pendant groups, poly-(N-acryloyl-L-phenylalanine-co-methyl methacrylate)-2 were prepared directly from N-acryloyl-L-phenylalanine (APhe) and methyl methacrylate (MMA) through atom transfer radical polymerization (ATRP) and microwave-assisted synthesis. In the first case, 9-(chloromethyl)anthracene was used as an ATRP-initiator to obtain a copolymer that contains amino acid sequences and anthracene end-capped units (0.03 molar fraction). Rapid synthesis of copolymer under microwave irradiation (250 W) in the presence of 1,1'-azobis(cyclohexanecarbonitrile) used as an initiator was followed of a functionalization of the formed copolymer with an anthracene derivative yielding copolyacrylate with pendant anthracene (0.02 molar fraction). The structure of the copolymers was verified by {sup 1}H NMR, UV-Vis and FTIR spectroscopy, gel permeation chromatography (GPC), and fluorescence spectroscopy. The fluorescence quenching process of anthracene which exists in copolymers by FeCl{sub 3}, cobalt acetate, nitrobenzene, maleic anhydride, diethylaniline and nitromethane in DMF solutions shows that this involves an electron transfer between the excited state anthracene and the present transitional metal cations, more efficiently being FeCl{sub 3} for poly-(APhe-co-MMA)-1 and cobalt acetate for the latter copolymer.

Ammonia chemistry in a flameless jet

Energy Technology Data Exchange (ETDEWEB)

Zieba, Mariusz; Schuster, Anja; Scheffknecht, Guenter [Institute of Process Engineering and Power Plant Technology, University of Stuttgart, Pfaffenwaldring 23, D-70569 Stuttgart (Germany); Brink, Anders; Hupa, Mikko [Process Chemistry Centre, Aabo Akademi University, Biskopsgatan 8, 20500 Aabo (Finland)

2009-10-15

In this paper, the nitrogen chemistry in an ammonia (NH{sub 3}) doped flameless jet is investigated using a kinetic reactor network model. The reactor network model is used to explain the main differences in ammonia chemistry for methane (CH{sub 4})-containing fuels and methane-free fuels. The chemical pathways of nitrogen oxides (NO{sub x}) formation and destruction are identified using rate-of-production analysis. The results show that in the case of natural gas, ammonia reacts relatively late at fuel lean condition leading to high NO{sub x} emissions. In the pre-ignition zone, the ammonia chemistry is blocked due to the absence of free radicals which are consumed by methane-methyl radical (CH{sub 3}) conversion. In the case of methane-free gas, the ammonia reacted very rapidly and complete decomposition was reached in the fuel rich region of the jet. In this case the necessary radicals for the ammonia conversion are generated from hydrogen (H{sub 2}) oxidation. (author)

Ammonia excretion in Caenorhabditis elegans: mechanism and evidence of ammonia transport of the Rhesus protein CeRhr-1

Science.gov (United States)

Adlimoghaddam, Aida; Boeckstaens, Mélanie; Marini, Anna-Maria; Treberg, Jason R.; Brassinga, Ann-Karen C.; Weihrauch, Dirk

2015-01-01

ABSTRACT The soil-dwelling nematode Caenorhabditis elegans is a bacteriovorous animal, excreting the vast majority of its nitrogenous waste as ammonia (25.3±1.2 µmol gFW−1 day−1) and very little urea (0.21±0.004 µmol gFW−1 day−1). Although these roundworms have been used for decades as genetic model systems, very little is known about their strategy to eliminate the toxic waste product ammonia from their bodies into the environment. The current study provides evidence that ammonia is at least partially excreted via the hypodermis. Starvation reduced the ammonia excretion rates by more than half, whereas mRNA expression levels of the Rhesus protein CeRhr-2, V-type H+-ATPase (subunit A) and Na+/K+-ATPase (α-subunit) decreased correspondingly. Moreover, ammonia excretion rates were enhanced in media buffered to pH 5 and decreased at pH 9.5. Inhibitor experiments, combined with enzyme activity measurements and mRNA expression analyses, further suggested that the excretion mechanism involves the participation of the V-type H+-ATPase, carbonic anhydrase, Na+/K+-ATPase, and a functional microtubule network. These findings indicate that ammonia is excreted, not only by apical ammonia trapping, but also via vesicular transport and exocytosis. Exposure to 1 mmol l−1 NH4Cl caused a 10-fold increase in body ammonia and a tripling of ammonia excretion rates. Gene expression levels of CeRhr-1 and CeRhr-2, V-ATPase and Na+/K+-ATPase also increased significantly in response to 1 mmol l−1 NH4Cl. Importantly, a functional expression analysis showed, for the first time, ammonia transport capabilities for CeRhr-1 in a phylogenetically ancient invertebrate system, identifying these proteins as potential functional precursors to the vertebrate ammonia-transporting Rh-glycoproteins. PMID:25740900

46 CFR 154.1760 - Liquid ammonia.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section 154.1760 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR....1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo tank...

Stabilities of protonated water-ammonia clusters

Science.gov (United States)

Sundén, A. E. K.; Støchkel, K.; Hvelplund, P.; Brøndsted Nielsen, S.; Dynefors, B.; Hansen, K.

2018-05-01

Branching ratios of water and ammonia evaporation have been measured for spontaneous evaporation from protonated mixed clusters H+(H2O)n(NH3)m in the size range 0 ≤ n ≤ 11 and 0 ≤ m ≤ 7. Mixed clusters evaporate water except for clusters containing six or more ammonia molecules, indicating the formation of a stable core of one ammonium ion surrounded by four ammonia molecules and a second shell consisting predominantly of water. We relate evaporative branching ratios to free energy differences between the products of competing channels and determine the free energy differences for clusters with up to seven ammonia molecules. Clusters containing up to five ammonia molecules show a very strong scaling of these free energy differences.

Titan's Ammonia Feature

Science.gov (United States)

Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

2011-01-01

NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

Characterization of mutations at the mouse phenylalanine hydroxylase locus

Energy Technology Data Exchange (ETDEWEB)

McDonald, J.D.; Charlton, C.K. [Wichita State Univ., KS (United States)

1997-02-01

Two genetic mouse models for human phenylketonuria have been characterized by DNA sequence analysis. For each, a distinct mutation was identified within the protein coding sequence of the phenylalanine hydroxylase gene. This establishes that the mutated locus is the same as that causing human phenylketonuria and allows a comparison between these mouse phenylketonuria models and the human disease. A genotype/phenotype relationship that is strikingly similar to the human disease emerges, underscoring the similarity of phenylketonuria in mouse and man. In PAH{sup ENU1}, the phenotype is mild. The Pah{sup enu1} mutation predicts a conservative valine to alanine amino acid substitution and is located in exon 3, a gene region where serious mutations are rare in humans. In PAH{sup ENU2} the phenotype is severe. The Pah{sup enu2} mutation predicts a radical phenylalanine to serine substitution and is located in exon 7, a gene region where serious mutations are common in humans. In PAH{sup ENU2}, the sequence information was used to devise a direct genotyping system based on the creation of a new Alw26I restriction endonuclease site. 26 refs., 2 figs., 1 tab.

27 CFR 21.96 - Ammonia, aqueous.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent by...

The measurement of muscle protein synthesis in broilers with a flooding dose technique: use of 15N-labelled phenylalanine, GC-MS and GC-C-IRMS.

Science.gov (United States)

Dänicke, S; Böttcher, W; Simon, O; Jeroch, H

2001-01-01

An experiment was carried out to measure fractional muscle protein synthesis rates (k(s)) in broilers with injection of a flooding dose of phenylalanine (1 ml/100 g body weight of 150 mM phenylalanine; 38 atom percent excess (APE) [15N]phenylalanine). K(s) was calculated from the [15N] enrichment in phenylalanine of tissue-free and protein-bound phenylalanine using both gas chromatography mass spectrometry (GC-MS) and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) for measurements after a 10 min isotope incorporation period. The tertiary-butyldimethylsilyl (t-BDMS) derivatives of phenylalanine were used for gas chromatographic separation in both systems. GC-MS and GC-C-IRMS were calibrated for a range of 7 to 37 [15N]APE and 0 to 0.62 [15N]APE, respectively, and for sample sizes of 0.45 to 4.5 nmol phenylalanine and 7 to 40 nmol phenylalanine, respectively. Reproducibility of standards as a measure of precision varied from 0.06 to 0.29 [15N]APE and from 0.0004 to 0.0018 [15N]APE in GC-MS and GC-C-IRMS, respectively. K(s) was measured in the m. pectoralis major of broilers fed rye based diets (56%) which were provided either unsupplemented (-) or supplemented (+) with an enzyme preparation containing xylanase. K(s) in breast muscles was significantly increased from 21.8%/d to 23.9%/d due to enzyme supplementation. It can be concluded from the study that the measurement of protein synthesis in broilers with the flooding dose technique can be carried out by using [15N]phenylalanine, GC-MS and GC-C-IRMS.

Biosynthesis and Metabolic Fate of Phenylalanine in Conifers

OpenAIRE

Pascual, María B.; El-Azaz, Jorge; de la Torre, Fernando N.; Cañas, Rafael A.; Avila, Concepción; Cánovas, Francisco M.

2016-01-01

The amino acid phenylalanine (Phe) is a critical metabolic node that plays an essential role in the interconnection between primary and secondary metabolism in plants. Phe is used as a protein building block but it is also as a precursor for numerous plant compounds that are crucial for plant reproduction, growth, development, and defense against different types of stresses. The metabolism of Phe plays a central role in the channeling of carbon from photosynthesis to the biosynthesis of pheny...

What Is the Best Blood Sampling Time for Metabolic Control of Phenylalanine and Tyrosine Concentrations in Tyrosinemia Type 1 Patients?

NARCIS (Netherlands)

van Dam, Esther; Daly, Anne; Venema-Liefaard, Gineke; van Rijn, Margreet; Derks, Terry G J; McKiernan, Patrick J; Heiner-Fokkema, Rebecca; MacDonald, Anita; van Spronsen, Francjan J

2017-01-01

BACKGROUND: Treatment of hereditary tyrosinemia type 1 with nitisinone and phenylalanine and tyrosine restricted diet has largely improved outcome, but the best blood sampling time for assessment of metabolic control is not known. AIM: To study diurnal and day-to-day variation of phenylalanine and

Ammonia synthesis using magnetic induction method (MIM)

Science.gov (United States)

Puspitasari, P.; Razak, J. Abd; Yahya, N.

2012-09-01

The most challenging issues for ammonia synthesis is to get the high yield. New approach of ammonia synthesis by using Magnetic Induction Method (MIM) and the Helmholtz Coils has been proposed. The ammonia detection was done by using Kjeldahl Method and FTIR. The system was designed by using Autocad software. The magnetic field of MIM was vary from 100mT-200mT and the magnetic field for the Helmholtz coils was 14mT. The FTIR result shows that ammonia has been successfully formed at stretching peaks 1097,1119,1162,1236, 1377, and 1464 cm-1. UV-VIS result shows the ammonia bond at 195nm of wavelength. The ammonia yield was increase to 244.72μmole/g.h by using the MIM and six pairs of Helmholtz coils. Therefore this new method will be a new promising method to achieve the high yield ammonia at ambient condition (at 25δC and 1atm), under the Magnetic Induction Method (MIM).

Evaluation of ammonia metabolism in the skeletal muscles of patients with cirrhosis using N-13 ammonia PET

International Nuclear Information System (INIS)

Susumu Shiomi; Etsushi Kawamura; Takehiro Hayashi; Ai Oe; Jin Kotani; Hirotaka Ishizu; Kenji Torii; Joji Kawabe; Akihiro Tamori; Daiki Habu; Tadashi Takeda; Shuhei Nishiguchi

2004-01-01

Purpose: Hepatic encephalopathy is one of the causes of death of patients with liver cirrhosis, and treatment of this encephalopathy is important for patients with liver cirrhosis. Ammonia plays a major role in the pathogenesis of hepatic encephalopathy. Ammonia is mainly generated in vivo by deamination of amino acids in proteins ingested as food, but some is produced by intestinal bacteria. The generated ammonia reaches the liver through the portal vein, is converted to urea by means of the urea cycle and excreted from the kidney. In patients with decreased hepatic functional reserve or those with porto-systemic shunt, ammonia level in the blood rises. The excessive ammonia in such cases is mainly metabolized in skeletal muscles, However, skeletal muscles have no urea cycle, and therefore metabolize ammonia by producing glutamine from glutamate. Branched-chain amino acids (BCAA) is required for this reaction. Ammonia is considered the major pathogenetic factor of hepatic encephalopathy. It has been reported in animal experiments that skeletal muscles compensate for the decreased ammonia metabolism in cirrhotic liver. Positron emission tomography (PET) with N-13 ammonia has been widely used for the evaluation of myocardial perfusion. We examined ammonia metabolism in the skeletal muscles in patients with liver cirrhosis before and after administration of BCAA using N-13 ammonia PET.. Methods: The subjects were patients with cirrhosis underlying hepatitis C virus infection. Case 1 was a 68-year-old man diagnosed with compensated liver cirrhosis. Both ascites and encephalopathy were absent. The red blood cell count was 365 X 10 4 /ml, the platelet count was 14.6 serum albumin concentration was 4.2 g/dl, the cholinesterase activity was 396 IU/l, the total bi concentration was 0.6 mg/dl, the blood ammonia was 52 g/dl, the prothrombin time was 150%, and branched-chain amino acid and tyrosin ratio (BTR) was 6.60. Case 2 was a 69-year-old woman diagnosed with

Influence of the composition of aqueous-alcohol solvents on the thermodynamic characteristics of L-phenylalanine dissolution at 298.15 K

International Nuclear Information System (INIS)

Badelin, Valentin G.; Smirnov, Valeriy I.

2011-01-01

Highlights: ► Enthalpies of L-phenylalanine dissolution have been measured in aqueous methanol, ethanol, 1-propanol and 2-propanol. ► The measured data were reported as functions of composition of water + alcohol mixtures. ► Enthalpy coefficients of pair-wise interactions have been analyzed in terms of McMillan-Mayer theory. ► A comparative analysis of the characteristics of dissolution of L-phenylalanine and some other L-amino acids in the similar systems has been made. - Abstract: The enthalpies of L-phenylalanine dissolution in aqueous methanol, ethanol, 1-propanol and 2-propanol have been determined by calorimetry at 298.15 K and alcohol mole fractions up to x 2 ∼0.4. The standard enthalpies of solution Δ sol H° and transfer Δ tr H° from water to the mixed solvent as well as the enthalpy coefficients of L-phenylalanine–alcohol pair-wise interactions were calculated. The interrelation of the enthalpies of dissolution and transfer for L-phenylalanine with structural features of alcohols has been determined. A comparative analysis of the thermodynamic characteristics of dissolution of L-phenylalanine and some other amino acids (glycine, L-alanine, L-threonine and L-valine) in the mixtures studied has been made.

Tracer experiment administering L-phenylalanine-U-14C and L-tyrosine-U-14C to the tissue slices of bamboo shoots

International Nuclear Information System (INIS)

Kozukue, E.; Mizuno, S.

1987-01-01

Uniformly 14 C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U- 14 C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U- 14 C was higher than that from tyrosine-U- 14 C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin

Method for forming ammonia

Science.gov (United States)

Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

2008-08-19

A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

Biosynthesis and metabolic fate of phenylalanine in conifers

Directory of Open Access Journals (Sweden)

María Belén Pascual

2016-07-01

Full Text Available The amino acid phenylalanine (Phe is a critical metabolic node that plays an essential role in the interconnection between primary and secondary metabolism in plants. Phe is used as a protein building block but it is also as a precursor for numerous plant compounds that are crucial for plant reproduction, growth, development and defense against different types of stresses. The metabolism of Phe plays a central role in the channeling of carbon from photosynthesis to the biosynthesis of phenylpropanoids. The study of this metabolic pathway is particularly relevant in trees, which divert large amounts of carbon into the biosynthesis of Phe-derived compounds, particularly lignin, an important constituent of wood. The trunks of trees are metabolic sinks that consume a considerable percentage of carbon and energy from photosynthesis, and carbon is finally immobilized in wood. This paper reviews recent advances in the biosynthesis and metabolic utilization of Phe in conifer trees. Two alternative routes have been identified: the ancient phenylpyruvate pathway that is present in microorganisms, and the arogenate pathway that possibly evolved later during plant evolution. Additionally, an efficient nitrogen recycling mechanism is required to maintain sustained growth during xylem formation. The relevance of phenylalanine metabolic pathways in wood formation, the biotic interactions and ultraviolet protection is discussed. The genetic manipulation and transcriptional regulation of the pathways are also outlined.

Biosynthesis and Metabolic Fate of Phenylalanine in Conifers.

Science.gov (United States)

Pascual, María B; El-Azaz, Jorge; de la Torre, Fernando N; Cañas, Rafael A; Avila, Concepción; Cánovas, Francisco M

2016-01-01

The amino acid phenylalanine (Phe) is a critical metabolic node that plays an essential role in the interconnection between primary and secondary metabolism in plants. Phe is used as a protein building block but it is also as a precursor for numerous plant compounds that are crucial for plant reproduction, growth, development, and defense against different types of stresses. The metabolism of Phe plays a central role in the channeling of carbon from photosynthesis to the biosynthesis of phenylpropanoids. The study of this metabolic pathway is particularly relevant in trees, which divert large amounts of carbon into the biosynthesis of Phe-derived compounds, particularly lignin, an important constituent of wood. The trunks of trees are metabolic sinks that consume a considerable percentage of carbon and energy from photosynthesis, and carbon is finally immobilized in wood. This paper reviews recent advances in the biosynthesis and metabolic utilization of Phe in conifer trees. Two alternative routes have been identified: the ancient phenylpyruvate pathway that is present in microorganisms, and the arogenate pathway that possibly evolved later during plant evolution. Additionally, an efficient nitrogen recycling mechanism is required to maintain sustained growth during xylem formation. The relevance of phenylalanine metabolic pathways in wood formation, the biotic interactions, and ultraviolet protection is discussed. The genetic manipulation and transcriptional regulation of the pathways are also outlined.

Sizing of an Ammonia Discharge Tank

Directory of Open Access Journals (Sweden)

Tuliagenda Beckfords

2011-01-01

Full Text Available Phosphate companies use well-stirred tanks to regulate the concentration of ammonia they discharge via their wastewater, preventing ammonia spikes from exceeding the cap set by the Environmental Protection Agency. This report discusses the methods used to determine the minimum possible volume of the tank required to regulate wastewater discharge. With this information, it was determined that the use of a stirring tank is an efficient and cost effective way to regulate ammonia discharge. Based on these results many other companies may use this method to decrease the negative effects of ammonia on the environment.

Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

International Nuclear Information System (INIS)

Rahimpour, M.R.; Asgari, A.

2008-01-01

In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO x emissions

Serum phenylalanine in preterm newborns fed different diets of human milk

Directory of Open Access Journals (Sweden)

Débora M. Thomaz

2014-09-01

Conclusion: The observed results demonstrated that human milk with fortifiers derived from human milk acted as a good substratum for preterm infant feeding both in the evaporated or the lyophilized form, without significant increases in plasma phenylalanine levels in comparison to human milk with commercial fortifier.

Blood phenylalanine control in phenylketonuria : a survey of 10 European centres

NARCIS (Netherlands)

Ahring, K.; Belanger-Quintana, A.; Dokoupil, K.; Gokmen-Ozel, H.; Lammardo, A. M.; MacDonald, A.; Motzfeldt, K.; Nowacka, M.; van Rijn, M.; Robert, M.

Background: Only limited data are available on the blood phenylalanine (Phe) concentrations achieved in European patients with phenylketonuria (PKU) on a low-Phe diet. Objective: A survey was conducted to compare blood Phe control achieved in diet-treated patients with PKU of different age groups in

Folate Biofortification in Hydroponically Cultivated Spinach by the Addition of Phenylalanine.

Science.gov (United States)

Watanabe, Sho; Ohtani, Yuta; Tatsukami, Yohei; Aoki, Wataru; Amemiya, Takashi; Sukekiyo, Yasunori; Kubokawa, Seiichi; Ueda, Mitsuyoshi

2017-06-14

Folate is an important vitamin mainly ingested from vegetables, and folate deficiency causes various health problems. Recently, several studies demonstrated folate biofortification in plants or food crops by metabolic engineering through genetic modifications. However, the production and sales of genetically modified foods are under strict regulation. Here, we developed a new approach to achieve folate biofortification in spinach (Spinacia oleracea) without genetic modification. We hydroponically cultivated spinach with the addition of three candidate compounds expected to fortify folate. As a result of liquid chromatography tandem mass spectrometry analysis, we found that the addition of phenylalanine increased the folate content up to 2.0-fold (306 μg in 100 g of fresh spinach), representing 76.5% of the recommended daily allowance for adults. By measuring the intermediates of folate biosynthesis, we revealed that phenylalanine activated folate biosynthesis in spinach by increasing the levels of pteridine and p-aminobenzoic acid. Our approach is a promising and practical approach to cultivate nutrient-enriched vegetables.

Manure application and ammonia volatilization

NARCIS (Netherlands)

Huijsmans, J.F.M.

2003-01-01

Keywords: manure application, ammonia volatilization, environmental conditions, application technique, incorporation technique, draught force, work organization, costs Livestock manure applied on farmland is an important source of ammonia (NH3) volatilization, and NH3 is a major atmospheric

Synthesis of ammonia with microwave plasma

International Nuclear Information System (INIS)

Xu Wenguo; Yu Aimin; Liu Jun; Jin Qinhan

1991-01-01

THe synthesis of ammonia absorbed on 13X zeolite with the aid of microwave plasma is described. The ammonia molecule absorbed on 13X zeolite as ammonium ions were detected by IR spectroscopy. The results obtained show that the ammonia synthesis is facilitated by the surface reactions of NH x (x = 1, 2) radicals adsorbed on zeolite with hydrogen atoms

Peripheral Ammonia as a Mediator of Methamphetamine Neurotoxicity

Science.gov (United States)

Halpin, Laura E.; Yamamoto, Bryan K.

2012-01-01

Ammonia is metabolized by the liver and has established neurological effects. The current study examined the possibility that ammonia contributes to the neurotoxic effects of methamphetamine (METH). The results show that a binge dosing regimen of METH to the rat increased plasma and brain ammonia concentrations that were paralleled by evidence of hepatotoxicity. The role of peripheral ammonia in the neurotoxic effects of METH was further substantiated by the demonstration that the enhancement of peripheral ammonia excretion blocked the increases in brain and plasma ammonia and attenuated the long term depletions of dopamine and serotonin typically produced by METH. Conversely, the localized perfusion of ammonia in combination with METH, but not METH alone or ammonia alone, into the striatum recapitulated the neuronal damage produced by the systemic administration of METH. Furthermore, this damage produced by the local administration of ammonia and METH was blocked by the GYKI 52466, an AMPA receptor antagonist. These findings highlight the importance of ammonia derived from the periphery as a small molecule mediator of METH neurotoxicity and more broadly emphasize the importance of peripheral organ damage as a possible mechanism that mediates the neuropathology produced by drugs of abuse and other neuroactive molecules. PMID:22993432

Ammonia gas permeability of meat packaging materials.

Science.gov (United States)

Karim, Faris; Hijaz, Faraj; Kastner, Curtis L; Smith, J Scott

2011-03-01

Meat products are packaged in polymer films designed to protect the product from exterior contaminants such as light, humidity, and harmful chemicals. Unfortunately, there is almost no data on ammonia permeability of packaging films. We investigated ammonia permeability of common meat packaging films: low-density polyethylene (LDPE; 2.2 mil), multilayer polyolefin (MLP; 3 mil), and vacuum (V-PA/PE; 3 mil, 0.6 mil polyamide/2.4 mil polyethylene). The films were fabricated into 10 × 5 cm pouches and filled with 50 mL deionized water. Pouches were placed in a plexiglass enclosure in a freezer and exposed to 50, 100, 250, or 500 ppm ammonia gas for 6, 12, 24, and 48 h at -17 ± 3 °C and 21 ± 3 °C. At freezing temperatures, no ammonia residues were detected and no differences in pH were found in the water. At room temperature, ammonia levels and pH of the water increased significantly (P packaging materials have low ammonia permeability and protect meat products exposed to ammonia leaks during frozen storage.

Cerebral ammonia metabolism in hyperammonemic rats

Energy Technology Data Exchange (ETDEWEB)

Cooper, A J; Mora, S N; Cruz, N F; Gelbard, A S

1985-06-01

The short-term metabolic fate of blood-borne (/sup 13/N)ammonia was determined in the brains of chronically (8- or 14-week portacaval-shunted rats) or acutely (urease-treated) hyperammonemic rats. Using a freeze-blowing technique it was shown that the overwhelming route for metabolism of blood-borne (/sup 13/N)ammonia in normal, chronically hyperammonemic and acutely hyperammonemic rat brain was incorporation into glutamine (amide). However, the rate of turnover of (/sup 13/N)ammonia to L-(amide-/sup 13/N)glutamine was slower in the hyperammonemic rat brain than in the normal rat brain. The activities of several enzymes involved in cerebral ammonia and glutamate metabolism were also measured in the brains of 14-week portacaval-shunted rats. The rat brain appears to have little capacity to adapt to chronic hyperammonemia because there were no differences in activity compared with those of weight-matched controls for the following brain enzymes involved in glutamate/ammonia metabolism: glutamine synthetase, glutamate dehydrogenase, aspartate aminotransferase, glutamine transaminase, glutaminase, and glutamate decarboxylase. The present findings are discussed in the context of the known deleterious effects on the CNS of high ammonia levels in a variety of diseases.

Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

Science.gov (United States)

Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

2017-02-01

The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH 4 Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-02-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study of interaction between tryptophan, tyrosine, and phenylalanine separately with silver nanoparticles by fluorescence quenching method

International Nuclear Information System (INIS)

Roy, S.; Das, T.K.

2015-01-01

Using the spectroscopic method, the individual interaction of the three biochemically important amino acids, which are constituents of protein, namely, tryptophan, tyrosine, and phenylalanine with biologically synthesized silver nanoparticles has been investigated. The obtained UV-Vis spectra show the formation of ground-state complexes between tryptophan, tyrosine, and phenylalanine with silver nanoparticles. Silver nanoparticles possess the ability to quench the intrinsic fluorescence of the aforesaid amino acids by a dynamic quenching process. The binding constant, number of binding sites, and corresponding thermodynamic parameters (ΔH, ΔS, and ΔG) based on the interaction system were calculated for 293, 303, and 313 K. In the case of tryptophan and phenylalanine, with increase in temperature, the binding constant K was found to decrease; conversely, it was found to increase with increase in temperature in the case of tyrosine. The thermodynamic results revealed that the binding process was spontaneous; hydrogen bonding and van der Waals interaction were the predominant forces responsible for the complex stabilization in the case of tryptophan and phenylalanine, respectively, whereas in the case of tyrosine, hydrophobic interaction was the sole force conferring stability. Moreover, the Förster non-radiation energy transfer theory has been applied to calculate the average binding distance among the above amino acids and silver nanoparticles. The results show a binding distance of <7 nm, which ensures that energy transfer does occur between the said amino acids and silver nanoparticles. (authors)

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

Energy Technology Data Exchange (ETDEWEB)

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

1995-05-01

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

New findings on cerebral ammonia uptake in HE using functional (13)N-ammonia PET

DEFF Research Database (Denmark)

Sørensen, Michael; Keiding, Susanne

2007-01-01

PET is a functional imaging technique suitable for studies of brain ammonia metabolism. Dynamic (13)N-ammonia PET yields time-courses of radioactivity concentrations in brain (PET camera) and blood (samples). Ahl et al. (Hepatology 40:73-79, 2004) and Keiding et al. (Hepatology 43:42-50, 2006...

Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia-tolerant Pacific hagfish.

Science.gov (United States)

Clifford, Alexander M; Weinrauch, Alyssa M; Edwards, Susan L; Wilkie, Michael P; Goss, Greg G

2017-08-01

Hagfish consume carrion, potentially exposing them to hypoxia, hypercapnia, and high environmental ammonia (HEA). We investigated branchial and cutaneous ammonia handling strategies by which Pacific hagfish ( Eptatretus stoutii ) tolerate and recover from high ammonia loading. Hagfish were exposed to HEA (20 mmol/l) for 48 h to elevate plasma total ammonia (T Amm ) levels before placement into divided chambers for a 4-h recovery period in ammonia-free seawater where ammonia excretion ( J Amm ) was measured independently in the anterior and posterior compartments. Localized HEA exposures were also conducted by subjecting hagfish to HEA in either the anterior or posterior compartments. During recovery, HEA-exposed animals increased J Amm in both compartments, with the posterior compartment comprising ~20% of the total J Amm compared with ~11% in non-HEA-exposed fish. Plasma T Amm increased substantially when whole hagfish and the posterior regions were exposed to HEA. Alternatively, plasma T Amm did not elevate after anterior localized HEA exposure. J Amm was concentration dependent (0.05-5 mmol/l) across excised skin patches at up to eightfold greater rates than in skin sections that were excised from HEA-exposed hagfish. Skin excised from more posterior regions displayed greater J Amm than those from more anterior regions. Immunohistochemistry with hagfish-specific anti-rhesus glycoprotein type c (α-hRhcg; ammonia transporter) antibody was characterized by staining on the basal aspect of hagfish epidermis while Western blotting demonstrated greater expression of Rhcg in more posterior skin sections. We conclude that cutaneous Rhcg proteins are involved in cutaneous ammonia excretion by Pacific hagfish and that this mechanism could be particularly important during feeding. Copyright © 2017 the American Physiological Society.

Chirality dependent interaction of ammonia with carbon nanotubes

Science.gov (United States)

Talukdar, Keka; Shantappa, Anil

2018-04-01

For the specific structure and extraordinary properties, carbon nanotubes (CNTs) have many applications in diversified fields. The interaction of CNTs with ammonia is a very interesting matter to study as it is related to the application of CNTs as ammonia sensor. Here the interaction of single walled zigzag, armchair and chiral carbon nanotubes is studied in respect of the change in energies before and after binding with ammonia by molecular dynamics simulation. Their deformation after simulation is modeled. The change of thermal conductivity of the CNTs is also found by simulation. The potential energy before and after absorption of ammonia gives useful information of the system. Thermal conductivities of the ammonia bound CNTs are changed considerably. It is observed that the potential energy and thermal conductivity both are changing for the interaction with ammonia and hence they are sensitive to ammonia binding.

Observations of atmospheric ammonia from TANSO-FTS/GOSAT

Science.gov (United States)

Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Shiomi, Kei

2017-04-01

Atmospheric ammonia has large impacts on the nitrogen cycles or atmospheric environment such as nucleation of PM2.5 particles. It is reported that ammonia in the atmosphere has been increasing rapidly with the growth of population globally and this trend must continue in the future. Satellite observation is an effective approach to get to know the global perspectives of the gas. Atmospheric ammonia is observable using the thermal infrared (TIR) spectra, and IASI, TES and CrIS had been revealed those distributions. GOSAT also has TIR band including the ammonia absorption bands. GOSAT has the shorter revisit cycle than that of the other hyper-spectral TIR sounders mentioned above, therefore, the shorter time-scale events can be represented. In addition to the importance of the impacts of ammonia itself, the concentration ratio between ammonia and the other trace gases such as CO which is one of the main targets of the GOSAT-2 project is useful as the indicator of their emission sources. In this study, we introduce an algorithm to retrieve the column amount of atmospheric ammonia based on non-linear optimal estimation (Rogers, 2000) from GOSAT spectra in the ammonia absorption band between 960 - 970 cm-1. Temperature and water vapor profiles are estimated in advance of the ammonia retrieval. The preliminary results showed significant high concentrations of ammonia in the Northern India and the Eastern China as pointed out in the previous researches. We will discuss the global distribution of ammonia in the presentation.

Experimental study of mixed additive of Ni(II) and piperazine on ammonia escape in CO2 capture using ammonia solution

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Wen, Jiaqi; Gao, Ran; Ma, Lan; Chai, Jin

2016-01-01

Highlights: • Compound additive was used to obtain high CO 2 absorption efficiency and low NH 3 escape. • Both organic material and metal ion were applied as compound additive. • Influences of additives on CO 2 absorption and NH 3 escape were investigated. • Possible mechanism and products were analyzed by XRD and UV–visible spectrophotometer. - Abstract: In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

Effect of dietary protein restriction on renal ammonia metabolism

Science.gov (United States)

Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Guo, Hui; Verlander, Jill W.

2015-01-01

Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia excretion in response to protein restriction and then we determined the molecular mechanism of the changes observed. Wild-type C57Bl/6 mice fed a 20% protein diet and then changed to 6% protein developed an 85% reduction in ammonia excretion within 2 days, which persisted during a 10-day study. The expression of multiple proteins involved in renal ammonia metabolism was altered, including the ammonia-generating enzymes phosphate-dependent glutaminase (PDG) and phosphoenolpyruvate carboxykinase (PEPCK) and the ammonia-metabolizing enzyme glutamine synthetase. Rhbg, an ammonia transporter, increased in expression in the inner stripe of outer medullary collecting duct intercalated cell (OMCDis-IC). However, collecting duct-specific Rhbg deletion did not alter the response to protein restriction. Rhcg deletion did not alter ammonia excretion in response to dietary protein restriction. These results indicate 1) dietary protein restriction decreases renal ammonia excretion through coordinated regulation of multiple components of ammonia metabolism; 2) increased Rhbg expression in the OMCDis-IC may indicate a biological role in addition to ammonia transport; and 3) Rhcg expression is not necessary to decrease ammonia excretion during dietary protein restriction. PMID:25925252

Production of tyrosine through phenylalanine hydroxylation bypasses the intrinsic feedback inhibition in Escherichia coli.

Science.gov (United States)

Huang, Jin; Lin, Yuheng; Yuan, Qipeng; Yan, Yajun

2015-04-01

Tyrosine is a proteinogenic aromatic amino acid that is often used as a supplement of food and animal feed, as well as a (bio-)synthetic precursor to various pharmaceutically or industrially important molecules. Extensive metabolic engineering efforts have been made towards the efficient and cost-effective microbial production of tyrosine. Conventional strategies usually focus on eliminating intrinsic feedback inhibition and redirecting carbon flux into the shikimate pathway. In this study, we found that continuous conversion of phenylalanine into tyrosine by the action of tetrahydromonapterin (MH4)-utilizing phenylalanine 4-hydroxylase (P4H) can bypass the feedback inhibition in Escherichia coli, leading to tyrosine accumulation in the cultures. First, expression of the P4H from Xanthomonas campestris in combination with an MH4 recycling system in wild-type E. coli allowed the strain to accumulate tyrosine at 262 mg/L. On this basis, enhanced expression of the key enzymes associated with the shikimate pathway and the MH4 biosynthetic pathway resulted in the elevation of tyrosine production up to 401 mg/L in shake flasks. This work demonstrated a novel approach to tyrosine production and verified the possibility to alleviate feedback inhibition by creating a phenylalanine sink.

Comparative study of ZnSe thin films deposited from modified chemical bath solutions with ammonia-containing and ammonia-free precursors

International Nuclear Information System (INIS)

Chen Liangyan; Zhang Daoli; Zhai Guangmei; Zhang Jianbing

2010-01-01

Ammonia is one of the complexing agents which are the most commonly used in the precursors of ZnSe thin films by chemical bath deposition, but its high volatility may be harmful to human beings and environments. In our experiments, ZnSe films were obtained from modified chemical solutions with ammonia-containing and ammonia-free precursors. X-ray diffraction, field-emission scanning electron microscope (FSEM), and absorption spectrum were applied to investigate the microstructure, morphology and optical properties of the samples obtained from both growth conditions, which were investigated in this work. The ammonia-free chemical bath deposited ZnSe films showed comparable properties with the ammonia-containing ones, indicating that ZnSe films from ammonia-free chemical solution may be preferred buffer layer in thin film solar cells with less environmental contamination.

Influence of additive L-phenylalanine on stabilization of metastable α-form of L-glutamic acid in cooling crystallization

Science.gov (United States)

Quang, Khuu Chau; Nhan, Le Thi Hong; Huyen, Trinh Thi Thanh; Tuan, Nguyen Anh

2017-09-01

The influence of additive amino acid L-phenylalanine on stabilization of metastable α-form of L-glutamic acid was investigated in cooling crystallization. The present study found that the additive L-phenylalanine could be used to stabilize the pure metastable α-form in L-glutamic acid crystallization, where the additive concentration of 0.05-0.1 (g/L) was sufficient to stabilize the 100% wt metastable α-form in solid product at L-glutamic acid concentration of 30-45 (g/L). Additionally, the present results indicated that the adsorption of additive L-phenylalanine on the (001) surface of α-form was more favorable than that of the β-form molecular, so the nucleation sites of stable β-form was occupied by additive molecular, which resulted in inhibition of nucleation and growth of β-form, allowing stabilization of metastable α-form.

Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

Science.gov (United States)

Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

2014-08-08

The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. Copyright © 2014, American Association for the Advancement of Science.

Synthesis of ammonia using sodium melt

OpenAIRE

Kawamura, Fumio; Taniguchi, Takashi

2017-01-01

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO2. Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO2. To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although severa...

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia...... recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7g-N/L during 30days, resulting in an average recovery rate of 80g-N/m2/d. Meanwhile, a maximum power density of 0.71±0.5W/m2 was generated at 2.85A/m2. Both current driven NH4+ migration...... and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative...

USE OF ZEOLITE FOR REMOVING AMMONIA AND AMMONIA-CAUSED TOXCITY IN MARINE TOXICITY IDENTIFCATION EVALUATIONS (TIES)

Science.gov (United States)

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifyi...

Resveratrol prevents ammonia toxicity in astroglial cells.

Directory of Open Access Journals (Sweden)

Larissa Daniele Bobermin

Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

Science.gov (United States)

Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

2012-01-01

Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

Ammonia production, excretion, toxicity, and defense in fish: A Review

Directory of Open Access Journals (Sweden)

Alex Y K Ip

2010-10-01

Full Text Available Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+ transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood-brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood-brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood-brain barrier of ammonotelic fishes and fishes with high brain ammonia-tolerance, respectively.

Ammonia transport in the kidney by Rhesus glycoproteins

Science.gov (United States)

Verlander, Jill W.

2014-01-01

Renal ammonia metabolism is a fundamental element of acid-base homeostasis, comprising a major component of both basal and physiologically altered renal net acid excretion. Over the past several years, a fundamental change in our understanding of the mechanisms of renal epithelial cell ammonia transport has occurred, replacing the previous model which was based upon diffusion equilibrium for NH3 and trapping of NH4+ with a new model in which specific and regulated transport of both NH3 and NH4+ across renal epithelial cell membranes via specific membrane proteins is required for normal ammonia metabolism. A major advance has been the recognition that members of a recently recognized transporter family, the Rhesus glycoprotein family, mediate critical roles in renal and extrarenal ammonia transport. The erythroid-specific Rhesus glycoprotein, Rh A Glycoprotein (Rhag), was the first Rhesus glycoprotein recognized as an ammonia-specific transporter. Subsequently, the nonerythroid Rh glycoproteins, Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg), were cloned and identified as ammonia transporters. They are expressed in specific cell populations and membrane domains in distal renal epithelial cells, where they facilitate ammonia secretion. In this review, we discuss the distribution of Rhbg and Rhcg in the kidney, the regulation of their expression and activity in physiological disturbances, the effects of genetic deletion on renal ammonia metabolism, and the molecular mechanisms of Rh glycoprotein-mediated ammonia transport. PMID:24647713

Ammonia Test

Science.gov (United States)

... of Conditions Not Listed? Not Listed? Acidosis and Alkalosis Adrenal Insufficiency and Addison Disease Alcoholism Allergies Alzheimer ... ammonia, but both can damage the eyes, skin, respiratory tract, and, if swallowed, the mouth, throat, and ...

Upwind impacts of ammonia from an intensive poultry unit

International Nuclear Information System (INIS)

Jones, L.; Nizam, M.S.; Reynolds, B.; Bareham, S.; Oxley, E.R.B.

2013-01-01

This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale. -- Highlights: •Ammonia from a poultry unit can be detected 2.8 km upwind. •Ammonia caused exceedance of critical levels 800 m and critical loads 2.8 km upwind. •Dune grassland species utilised ammonia as a nutrient source. •Plant biomass increased at low levels of ammonia and total nitrogen deposition. •Soil C pools are predicted to increase by 9% over 50 years due to the excess ammonia. -- Ammonia from a poultry unit has upwind impacts, exceeding critical levels 800 m and critical loads 2.8 km upwind, and increasing biomass and tissue N of dune grassland species

Staging properties of potassium-ammonia ternary graphite intercalation compounds at high ammonia pressure

Science.gov (United States)

Qian, X. W.; Solin, S. A.

1989-04-01

The pressure dependence of the (00l) x-ray diffraction patterns of the ternary graphite intercalation compound K(NH3)xC24 has been studied in the range 0.5-11 kbar (for which x~4.5) using a diamond anvil cell. A special apparatus for loading the cell with liquid ammonia at room temperature has been constructed and is briefly described. In these experiments, the pressure-transmitting fluid was also an intercalant, namely ammonia. Therefore, the chemical potential of this species was linearly coupled to the applied pressure in contrast to the usual case where the pressure-transmitting fluid is chemically passive. The pressure dependences of the basal spacings and of the relative intensities of key reflections have been measured, as have the compressibilities of the stage-1 and stage-2 components of the two-phase system. Basal-spacing anomalies and anomalies in the relative intensities occur at pressures of ~3.5 and 8.0 kbar and are tentatively attributed to in-plane coordination changes in the potassium-ammonia ratio. Using thermodynamic arguments and Le Chatelier's principle we show quantitatively that a staging phase transition from pure stage-1 phase to an admixture of stage-1 and stage-2 is expected with increased pressure above 10 bar in agreement with experiment. The saturation ammonia compositions (x values) of the admixed stages are found to be 4.5 and 5.4 for the stage-1 and -2 components, respectively. This result is interpreted as evidence that the composition is not sterically limited but is determined by the binding energy of ammonia for potassium and by the perturbation to this energy from the guest-host interaction.

1 Synthesis of Selected Phenylalanine Esters C1 to C4 and their ...

African Journals Online (AJOL)

Figure 1 Synthesis of Taxol via the Wieland Miescher Ketone. Important natural products .... ml) at 0°C. Thionyl chloride (1ml, 13.8 mmol) was added dropwise to the reaction mixture ... L-Phenylalanine propyl ester hydrochloride. (Yield: 93%).

Mechanism of ammonia excretion in the freshwater leech Nephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia

Science.gov (United States)

Quijada-Rodriguez, Alex R.; Treberg, Jason R.

2015-01-01

Remarkably little is known about nitrogenous excretion in freshwater invertebrates. In the current study, the nitrogen excretion mechanism in the carnivorous ribbon leech, Nephelopsis obscura, was investigated. Excretion experiments showed that the ribbon leech is ammonotelic, excreting 166.0 ± 8.6 nmol·grams fresh weight (gFW)−1·h−1 ammonia and 14.7 ± 1.9 nmol·gFW−1·h−1 urea. Exposure to high and low pH hampered and enhanced, respectively, ammonia excretion rates, indicating an acid-linked ammonia trapping mechanism across the skin epithelia. Accordingly, compared with body tissues, the skin exhibited elevated mRNA expression levels of a newly identified Rhesus protein and at least in tendency the Na+/K+-ATPase. Pharmacological experiments and enzyme assays suggested an ammonia excretion mechanism that involves the V-ATPase, Na+/K+-ATPase, and carbonic anhydrase, but not necessarily a functional microtubule system. Most importantly, functional expression studies of the identified Rh protein cloned from leech skin tissue revealed an ammonia transport capability of this protein when expressed in yeast. The leech Rh-ammonia transporter (NoRhp) is a member of the primitive Rh protein family, which is a sister group to the common ancestor of vertebrate ammonia-transporting Rh proteins. Exposure to high environmental ammonia (HEA) caused a new adjustment of body ammonia, accompanied with a decrease in NoRhp and Na+/K+-ATPase mRNA levels, but unaltered ammonia excretion rates. To our knowledge, this is only the second comprehensive study regarding the ammonia excretion mechanisms in a freshwater invertebrate, but our results show that basic processes of ammonia excretion appear to also be comparable to those found in freshwater fish, suggesting an early evolution of ionoregulatory mechanisms in freshwater organisms. PMID:26180186

Ammonia Generation via a Graphene-Coated Nickel Catalyst

Directory of Open Access Journals (Sweden)

Fei Lu

2017-05-01

Full Text Available A novel graphene-coated Ni electrode was developed in this investigation to improve corrosion resistance while unexpectedly enhancing the ammonia generation rate in the electrochemically induced urea to ammonia (eU2A process, which is an electrochemical onsite ammonia generation method. The development of the electrode is crucial for the eU2A reactions since in the ammonia generation process, the concentration of ammonia is inevitably high on the surface of the electrode, leading to severe corrosion of the electrode and the loss of generated ammonia as well. In this paper, the graphene was derived from raw coal by using the chemical vapor deposition method and self-lifted onto a Ni electrode to form a protective layer for corrosion prevention. Transmission electron microscopy showed the synthesized graphene had few-layers and Raman spectroscopy indicated that the coating of graphene was stable during the eU2A reaction. As a result, the ammonia corrosion of the Ni electrode was dramatically reduced by ~20 times with the graphene coating method. More importantly, a higher ammonia generation rate (~2 times was achieved using the graphene-coated Ni working electrode compared to a bare Ni electrode in the eU2A process.

Safety assessment of ammonia as a transport fuel

Energy Technology Data Exchange (ETDEWEB)

Duijm, N.J.; Markert, F.; Lundtang paulsen, Jette

2005-02-01

This report describes the safety study performed as part of the EU supported project 'Ammonia Cracking for Clean Electric Power Technology' The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal and accident (collision) conditions, safety of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of other existing or alternative fuels. The conclusion is that the hazards in relation to ammonia need to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle - Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system - Road transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zones between refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldnt cause more risks than currently used fuels (using current practice). (au)

Study of Ammonia Emissions in a Ventilated Pig Pen

DEFF Research Database (Denmark)

Rong, Li

Pig productions cause a wide emission of odors, such as ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4). Ammonia is one of the most important emissions for evaluating the air quality either in animal buildings or atmospheric environment. In studies of ammonia emission from animal buildings...... emission rate was measured in a wind tunnel under different airflow and ammonium solution temperatures. This investigation provides a general understanding for the influence of velocity, turbulence intensity and temperature on the ammonia emissions. The relationship between ammonia emissions and boundary...... through the air-liquid interface is suggested from vapor-liquid equilibrium properties of ammonia water. Furthermore, the effects of airflow and temperature on ammonia mass transfer coefficient are also analyzed under different concentration boundary conditions determined by various Henry’s law constant...

Glycopyrrolate in toxic exposure to ammonia gas

Directory of Open Access Journals (Sweden)

Bhalla A

2011-01-01

Full Text Available Ammonia (NH 3 is a highly water-soluble, colorless, irritant gas with a unique pungent odor. Liquid ammonia stored under high pressure is still widely used for refrigeration in cold stores used for storing grains. Severe toxicity may occur following accidental exposure. We report an interesting case of accidental exposure to ammonia treated with glycopyrrolate along with other supportive measures.

The importance of the ammonia purification process in ammonia-water absorption systems

International Nuclear Information System (INIS)

Fernandez-Seara, Jose; Sieres, Jaime

2006-01-01

Practical experience in working with ammonia-water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process. The study has been performed considering a single stage system with a distillation column with complete condensation. The ammonia purification effectiveness of the column is analysed in terms of the efficiencies in the stripping and rectifying sections and the reflux ratio. By varying the efficiencies from 0 to 1, systems with neither the rectifying nor stripping section, with either the rectifying or stripping section, or with both sections can be considered. The impact of the ammonia purification process on the absorption system performance is studied based on the column efficiencies and reflux ratio; and its effects on refrigerant concentration, system COP, system pressures and main system mass flow rates and concentrations are analysed. When the highest efficiency rectifying sections are used a combination of generation temperature and reflux ratio which leads to optimum COP values is found. The analysis covers different operating conditions with air and water cooled systems from refrigeration to air conditioning applications by changing the evaporation temperature. The importance of rectification in each kind of application is evaluated

Age–related psychophysiological vulnerability to phenylalanine in phenylketonuria

Directory of Open Access Journals (Sweden)

Vincenzo eLeuzzi

2014-06-01

Full Text Available Background. Phenylketonuria (PKU is caused by the inherited defect of the phenylalanine hydroxylase enzyme, which converts phenylalanine (Phe into tyrosine (Tyr. Neonatal screening programs and early treatment have radically changed the natural history of PKU. Nevertheless, an increased risk of neurocognitive and psychiatric problems in adulthood remains a challenging aspect of the disease. In order to assess the vulnerability of complex skills to Phe, we explored: a the effect of a rapid increase in blood Phe levels on event-related potentials (ERP in PKU subjects during their second decade of life; b the association (if existing between psychophysiological and neurocognitive features.Methods. Seventeen early-treated PKU subjects, aged 10 to 20, underwent ERP (Mismatch Negativity, auditory P300, Contingent Negative Variation (CNV, and Intensity Dependence of Auditory Evoked Potentials recording before and 2 hours after an oral loading of Phe. Neurocognitive functioning, historical and concurrent biochemical values of blood Phe, Tyr, and Phe/Tyr ratio, were all included in the statistical analysis.Results. ERP components were normally detected in all the subjects. In subjects younger than 13 CNV amplitude, W2-CNV area, P3b latency, and Reaction Times in motor responses were negatively influenced by Phe loading. Independently from the psychophysiological vulnerability, some neurocognitive skills were more impaired in younger patients. No correlation was found between biochemical alterations and neurocognitive and psychophysiological findings. Conclusion. The vulnerability of the emerging neurocognitive functions to Phe suggests a strict metabolic control in adolescents affected by PKU and a neurodevelopmental approach in the study of neurocognitive outcome in PKU.

Biochemical studies on the Combination of Bemul-wax and Calcium ...

African Journals Online (AJOL)

Afolabi S

2011-04-04

Apr 4, 2011 ... coating combined with calcium chloride treatment ... storage methods for sweet potatoes are by leaving the ..... Phenylalanine ammonia lyase activity of treated sweet potato at ambient temperature ..... Theme: Innovative.

Release of ammonia from HAN-type PHA

International Nuclear Information System (INIS)

Zamecnik, J.R.

1992-01-01

A preliminary design basis for ammonia scrubbers in the DWPF has been issued. This design basis is based on a theoretical model of ammonia evolution from the SRAT, SME and RCT. It is desirable to acquire actual process data on ammonia evolution prior to performing detailed design of scrubbers for DWPF. The evolution of ammonia from the SRAT and SME in the Integrated DWPF Melter System (IDMS) was investigated during the HM4 run. In this run, Precipitate Hydrolysis Aqueous (PHA), which was made in the Precipitate Hydrolysis Experimental Facility (PHEF) using the HAN (hydroxylamine nitrate) process was used, thus resulting in PHA with a high concentration of ammonium ion

Converting Wind Energy to Ammonia at Lower Pressure

International Nuclear Information System (INIS)

Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

2017-01-01

Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

Ammonia Affects Astroglial Proliferation in Culture

Science.gov (United States)

Bodega, Guillermo; Segura, Berta; Ciordia, Sergio; Mena, María del Carmen; López-Fernández, Luis Andrés; García, María Isabel; Trabado, Isabel; Suárez, Isabel

2015-01-01

Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis. PMID:26421615

Ammonia Affects Astroglial Proliferation in Culture.

Directory of Open Access Journals (Sweden)

Guillermo Bodega

Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

Tracer experiment administering L-phenylalanine-U-{sup 14}C and L-tyrosine-U-{sup 14}C to the tissue slices of bamboo shoots

Energy Technology Data Exchange (ETDEWEB)

Kozukue, E. [Kenmei Women' s Junior Coll., Himeji, Hyogo (Japan); Mizuno, S.

1987-09-15

Uniformly {sup 14}C-labeled L-phenylalanine and L-tyrosine were administered to tissue slices of both top and base sections of bamboo shoots. Alcohol soluble substances were extracted and then separated into organic acid, sugar and amino acid fractions by ion exchange chromatography. The homogentisic acid fraction among the organic acids was collected by high-performance liquid chromatography (HPLC) and its radioactivity was measured, while the alcohol insoluble residue was used for the analysis of lignin aldehyde by the method of alkaline nitrobenzene oxidation. 1. The two labeled amino acids were steadily incorporated into the tissues during incubation and rapidly converted to organic acid, sugar and alcohol insoluble residue, especially the latter. 2. On determining the amount of phenylalanine converted to tyrosine, it was found that this was extremely small. 3. The incorporation of phenylalanine-U-{sup 14}C into alcohol insoluble residue was higher than that of tyrosine in both sections. 4. Although the conversion into lignin aldehyde from phenylalanine-U-{sup 14}C was higher than that from tyrosine-U-{sup 14}C, it was found that tyrosine incorporated into the shoots was converted to a remarkable extent for formation of lignin aldehyde. 5. The incorporation of phenylalanine and tyrosine into homogentisic acid was very low. From these results, we assume that the conversion of phenylalanine to tyrosine or of tyrosine to homogentisic acid is very small, and that a part of the high amount of tyrosine in the shoots may be used for formation of lignin.

Ammonium recruitment and ammonia transport by E. coli ammonia channel AmtB

DEFF Research Database (Denmark)

Nygaard, Thomas Pedersen; Rovira, C.; Peters, Günther H.j.

2006-01-01

To investigate substrate recruitment and transport across the Escherichia coli Ammonia transporter B (AmtB) protein, we performed molecular dynamics simulations of the AmtB trimer. We have identified residues important in recruitment of ammonium and intraluminal binding sites selective of ammonium......, which provide a means of cation selectivity. Our results indicate that A162 guides translocation of an extraluminal ammonium into the pore lumen. We propose a mechanism for transporting the intraluminally recruited proton back to periplasm. Our mechanism conforms to net transport of ammonia and can...

Ammonia concentrations in canine whole blood, EDTA-anticoagulated whole blood, and plasma measured by use of a point-of-care ammonia meter.

Science.gov (United States)

Odunayo, Adesola; Tobias, Karen M; Okafor, Chika C; Flatland, Bente

2017-11-01

OBJECTIVE To investigate the use of canine whole blood (WB) for measurement of ammonia concentration by use of a point-of-care ammonia meter and to compare results of measuring ammonia concentrations in WB, EDTA-anticoagulated WB, and plasma. ANIMALS 40 client-owned dogs. PROCEDURES A blood sample (2 mL) was obtained from each dog. One drop of WB was immediately applied to a test strip for evaluation with an ammonia meter. The remainder of the blood sample was placed in an EDTA-containing tube, and 1 drop of EDTA-anticoagulated WB was applied to a test strip. The remaining EDTA-anticoagulated WB sample was centrifuged, and the plasma was harvested and placed on ice. One drop of plasma was applied to a test strip; the remainder of the plasma sample was transported on ice and used for ammonia measurement with a reference laboratory instrument. All samples were tested within 1 hour after sample collection. Results were evaluated to detect significant differences in ammonia concentration. RESULTS Ammonia concentrations did not differ significantly between WB and EDTA-anticoagulated WB and between plasma samples measured with the meter and reference laboratory instrument. However, median ammonia concentration was significantly higher in plasma than in WB or EDTA-anti-coagulated WB. CONCLUSIONS AND CLINICAL RELEVANCE Anticoagulant-free WB was a valid sample for measurement by use of the ammonia meter. Plasma samples had higher ammonia concentrations than did WB samples. Results for each sample type should be interpreted by use of specimen- and method-specific reference intervals.

Changes of ammonia, urea contents and transaminase activity in the body during aerial exposure and ammonia loading in Chinese loach Paramisgurnus dabryanus.

Science.gov (United States)

Zhang, Yun-Long; Zhang, Hai-Long; Wang, Ling-Yu; Gu, Bei-Yi; Fan, Qi-Xue

2017-04-01

The Paramisgurnus dabryanus was exposed to 30 mmol L -1 NH 4 Cl solution and air to assessing the change of body ammonia and urea contents and the activities of alanine aminotransferase (ALT) and aspartate transaminase (AST). After 48 h of ammonia exposure, ammonia concentration in the plasma, brain, liver and muscle were 3.3-fold, 5.6-fold, 3.5-fold and 4.2-fold, respectively, those of the control values. Plasma, brain, liver and muscle ammonia concentrations increased to 2.2-fold, 3.3-fold, 2.5-fold and 2.9-fold, respectively, those of control values in response to 48 h of aerial exposure. Within the given treatment (ammonia or aerial exposure), there was no change in plasma, brain and liver urea concentrations between exposure durations. The plasma ALT activity was significantly affected by exposure time during aerial exposure, while the liver ALT activity was not affected by ammonia or aerial exposure. Exposure to NH 4 Cl or air had no effect on either plasma or liver AST activity. Our results suggested that P. dabryanus could accumulate quite high level of internal ammonia because of the high ammonia tolerance in its cells and tissues, and NH 3 volatilization would be a possible ammonia detoxification strategy in P. dabryanus. Urea synthesis was not an effective mechanism to deal with environmental or internal ammonia problem. The significant increase of ALT activity in plasma during aerial exposure, indicating that alanine synthesis through certain amino acid catabolism may be subsistent in P. dabryanus.

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Hydrothermal oxidation of ammonia/organic waste mixtures

International Nuclear Information System (INIS)

Luan, Li; Proesmans, P.I.; Buelow, S.J.

1997-01-01

Hydrothermal oxidation is a promising new technology for the treatment of radioactive contaminated hazardous organic wastes. Los Alamos National Laboratory is currently evaluating this technology for the U. S. Department of Energy. In this paper, we present experimental results from the study of the hydrothermal oxidation of an ammonia/alcohol/uranium waste mixture. The use of a co-oxidant system consisting of hydrogen peroxide combined with nitrate is discussed. Experiments demonstrate near complete destruction of ammonia and organic compounds at 500 degrees C, 38 MPa, and 50 seconds reaction time. The ammonia and total organic carbon (TOC) concentrations in a waste simulant is reduced from 8,500 mg/L of ammonia and 12,500 mg/L TOC to 30 mg/L ammonia and less than 10 mg/L TOC. The major reaction products are CO 2 , N 2 , and a small amount of N 2 O. Comparison experiments with nitrate and hydrogen peroxide used individually show the advantage of the co-oxidant system

Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

Science.gov (United States)

Palaniappan, Ramasamy

Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia

Regeneration of ammonia borane from polyborazylene

Science.gov (United States)

Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

2013-02-05

Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

Development of an EGFRvIII specific recombinant antibody

Directory of Open Access Journals (Sweden)

Li Gordon

2010-10-01

Full Text Available Abstract Background EGF receptor variant III (EGFRvIII is the most common variant of the EGF receptor observed in human tumors. It results from the in frame deletion of exons 2-7 and the generation of a novel glycine residue at the junction of exons 1 and 8. This novel juxtaposition of amino acids within the extra-cellular domain of the EGF receptor creates a tumor specific and immunogenic epitope. EGFRvIII expression has been seen in many tumor types including glioblastoma multiforme (GBM, breast adenocarcinoma, non-small cell lung carcinoma, ovarian adenocarcinoma and prostate cancer, but has been rarely observed in normal tissue. Because this variant is tumor specific and highly immunogenic, it can be used for both a diagnostic marker as well as a target for immunotherapy. Unfortunately many of the monoclonal and polyclonal antibodies directed against EGFRvIII have cross reactivity to wild type EGFR or other non-specific proteins. Furthermore, a monoclonal antibody to EGFRvIII is not readily available to the scientific community. Results In this study, we have developed a recombinant antibody that is specific for EGFRvIII, has little cross reactivity for the wild type receptor, and which can be easily produced. We initially designed a recombinant antibody with two anti-EGFRvIII single chain Fv's linked together and a human IgG1 Fc component. To enhance the specificity of this antibody for EGFRvIII, we mutated tyrosine H59 of the CDRH2 domain and tyrosine H105 of the CDRH3 domain to phenylalanine for both the anti-EGFRvIII sequence inserts. This mutated recombinant antibody, called RAbDMvIII, specifically detects EGFRvIII expression in EGFRvIII expressing cell lines as well as in EGFRvIII expressing GBM primary tissue by western blot, immunohistochemistry (IHC and immunofluorescence (IF and FACS analysis. It does not recognize wild type EGFR in any of these assays. The affinity of this antibody for EGFRvIII peptide is 1.7 × 107 M-1 as

The metabolism of L-phenylalanine and L-tyrosine by liver cells isolated from adrenalectomized rats and from streptozotocin-diabetic rats.

OpenAIRE

Stanley, J C; Fisher, M J; Pogson, C I

1985-01-01

Flux through, and maximal activities of, key enzymes of phenylalanine and tyrosine degradation were measured in liver cells prepared from adrenalectomized rats and from streptozotocin-diabetic rats. Adrenalectomy decreased the phenylalanine hydroxylase flux/activity ratio; this was restored by steroid treatment in vivo. Changes in the phosphorylation state of the hydroxylase may mediate these effects; there was no significant change in the maximal activity of the hydroxylase. Tyrosine metabol...

Review of Options for Ammonia/Ammonium Management

Energy Technology Data Exchange (ETDEWEB)

Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-05-06

This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

Surface - atmosphere exchange of ammonia over grazed pasture

NARCIS (Netherlands)

Plantaz, M.A.H.G.

1998-01-01

This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.
Ammonia exchange

Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

Science.gov (United States)

Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

Power-to-ammonia: rethinking the role of ammonia – from a value product to a flexible energy carrier (FlexNH3)

NARCIS (Netherlands)

Bennani, Yasmina; Perl, Andras; Patil, Anish; van Someren, Christian; Heijne, Leo; van Steenis, Machiel

2016-01-01

This report focuses on the feasibility of the power-to-ammonia concept. Power-to-ammonia uses produced excess renewable electricity to electrolyze water, and then to react the obtained hydrogen with nitrogen, which is obtained through air separation, to produce ammonia. This process may be used as a

PpNAC1, a main regulator of phenylalanine biosynthesis and utilization in maritime pine.

Science.gov (United States)

Pascual, María Belén; Llebrés, María-Teresa; Craven-Bartle, Blanca; Cañas, Rafael A; Cánovas, Francisco M; Ávila, Concepción

2018-05-01

The transcriptional regulation of phenylalanine metabolism is particularly important in conifers, long-lived species that use large amounts of carbon in wood. Here, we show that the Pinus pinaster transcription factor, PpNAC1, is a main regulator of phenylalanine biosynthesis and utilization. A phylogenetic analysis classified PpNAC1 in the NST proteins group and was selected for functional characterization. PpNAC1 is predominantly expressed in the secondary xylem and compression wood of adult trees. Silencing of PpNAC1 in P. pinaster results in the alteration of stem vascular radial patterning and the down-regulation of several genes associated with cell wall biogenesis and secondary metabolism. Furthermore, transactivation and EMSA analyses showed that PpNAC1 is able to activate its own expression and PpMyb4 promoter, while PpMyb4 is able to activate PpMyb8, a transcriptional regulator of phenylalanine and lignin biosynthesis in maritime pine. Together, these results suggest that PpNAC1 is a functional ortholog of the ArabidopsisSND1 and NST1 genes and support the idea that key regulators governing secondary cell wall formation could be conserved between gymnosperms and angiosperms. Understanding the molecular switches controlling wood formation is of paramount importance for fundamental tree biology and paves the way for applications in conifer biotechnology. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

Science.gov (United States)

Martens-Habbena, Willm; Stahl, David A

2011-01-01

The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

The origin of mouth-exhaled ammonia.

Science.gov (United States)

Chen, W; Metsälä, M; Vaittinen, O; Halonen, L

2014-09-01

It is known that the oral cavity is a production site for mouth-exhaled NH3. However, the mechanism of NH3 production in the oral cavity has been unclear. Since bacterial urease in the oral cavity has been found to produce ammonia from oral fluid urea, we hypothesize that oral fluid urea is the origin of mouth-exhaled NH3. Our results show that under certain conditions a strong correlation exists between oral fluid urea and oral fluid ammonia (NH4(+)+NH3) (rs = 0.77, p oral fluid NH3 and mouth-exhaled NH3 (rs = 0.81, p oral fluid pH. Bacterial urease catalyses the hydrolysis of oral fluid urea to ammonia (NH4(+)+NH3). Oral fluid ammonia (NH4(+)+NH3) and pH determine the concentration of oral fluid NH3, which evaporates from oral fluid into gas phase and turns to mouth-exhaled NH3.

15N-enrichments of ammonia and glutamine in blood after infusion of 15N-ammonia in chickens fed low or high protein diet

International Nuclear Information System (INIS)

Karasawa, Yutaka; Koh, Katsuki

1985-01-01

In this experment, the blood ammonia and glutamine amide came from infused ammonia were determined when N-15 labeled ammonium acetate was intraportally infused into the chickens fed 5 or 20 % protein diet. The data obtained indicated that the infused ammonia was taken into blood glutamine amide, and also accumulated in blood as it is, in both dietary groups. 10 to 12 months old White Leghorn male birds were used. The experimental diet was fed once a day for 5 days to the birds weighting about 1.2 kg by 35 g per kg body weight. The experimental diet was consumed within 40 min in all cases. Cardiac and portal catheterization were performed for blood collection and ammonia infusion, respectively. After finishing the infusion, blood samples were taken to analyze the ammonia and glutamine contents and their N-15 enrichment. Statistical difference was not observed in the appearance of N-15 in ammonia and glutamine amide between two dietary groups. The N-15 enrichment in blood ammonia and the amide of plasma glutamine, and the calculated exogenous nitrogen in the ammonia and glutamine amide tended to be more in the 5 % protein diet group than the other. (Kako, I.)

Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

Science.gov (United States)

Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

2012-05-01

A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

Ammonia as a respiratory gas in water and air-breathing fishes.

Science.gov (United States)

Randall, David J; Ip, Yuen K

2006-11-01

Ammonia is produced in the liver and excreted as NH(3) by diffusion across the gills. Elevated ammonia results in an increase in gill ventilation, perhaps via stimulation of gill oxygen chemo-receptors. Acidification of the water around the fish by carbon dioxide and acid excretion enhances ammonia excretion and constitutes "environmental ammonia detoxification". Fish have difficulties in excreting ammonia in alkaline water or high concentrations of environmental ammonia, or when out of water. The mudskipper, Periphthalmodon schlosseri, is capable of active NH(4)(+) transport, maintaining low internal levels of ammonia. To prevent a back flux of NH(3), these air-breathing fish can increase gill acid excretion and reduce the membrane NH(3) permeability by modifying the phospholipid and cholesterol compositions of their skin. Several air-breathing fish species can excrete ammonia into air through NH(3) volatilization. Some fish detoxify ammonia to glutamine or urea. The brains of some fish can tolerate much higher levels of ammonia than other animals. Studies of these fish may offer insights into the nature of ammonia toxicity in general.

Combining metabolic and process engineering strategies to improve recombinant glycoprotein production and quality.

Science.gov (United States)

Karengera, Eric; Durocher, Yves; De Crescenzo, Gregory; Henry, Olivier

2017-11-01

Increasing recombinant protein production while ensuring a high and consistent protein quality remains a challenge in mammalian cell culture process development. In this work, we combined a nutrient substitution approach with a metabolic engineering strategy that improves glucose utilization efficiency. This combination allowed us to tackle both lactate and ammonia accumulation and investigate on potential synergistic effects on protein production and quality. To this end, HEK293 cells overexpressing the pyruvate yeast carboxylase (PYC2) and their parental cells, both stably producing the therapeutic glycoprotein interferon α2b (IFNα2b), were cultured in media deprived of glutamine but containing chosen substitutes. Among the tested substitutes, pyruvate led to the best improvement in growth (integral of viable cell density) for both cell lines in batch cultures, whereas the culture of PYC2 cells without neither glutamine nor any substitute displayed surprisingly enhanced IFNα2b production. The drastic reduction in both lactate and ammonia in the cultures translated into extended high viability conditions and an increase in recombinant protein titer by up to 47% for the parental cells and the PYC2 cells. Product characterization performed by surface plasmon resonance biosensing using Sambucus nigra (SNA) lectin revealed that the increase in yield was however accompanied by a reduction in the degree of sialylation of the product. Supplementing cultures with glycosylation precursors and a cofactor were effective at counterbalancing the lack of glutamine and allowed improvement in IFNα2b quality as evaluated by lectin affinity. Our study provides a strategy to reconcile protein productivity and quality and highlights the advantages of PYC2-overexpressing cells in glutamine-free conditions.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir; Owen, Kyle

2015-01-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir

2015-09-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Atmospheric behaviour of ammonia and ammonium

NARCIS (Netherlands)

Asman, W.A.H.

1987-01-01

1.4.1 Scope of this thesis

A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid

Effect of inhaled formyl-methionyl-leucyl-phenylalanine on airway function.

OpenAIRE

Berend, N; Peters, M J; Armour, C L; Black, J L; Ward, H E

1988-01-01

Formyl-methionyl-leucyl-phenylalanine (FMLP), a synthetic, acylated tripeptide analogous to bacterial chemotactic factors, has been shown to cause bronchoconstriction in guinea pig, rabbit, and human airways in vitro. To determine whether FMLP causes bronchoconstriction in man in vivo, a preliminary study was undertaken in which five non-smokers (mean age 35 years, FEV1 94% (SEM 5%) predicted) and five smokers (mean age 34 years, FEV1 93% (6%) predicted) inhaled aerosols of FMLP. None of the ...

46 CFR 151.50-32 - Ammonia, anhydrous.

Science.gov (United States)

2010-10-01

... enclosed anhydrous ammonia tanks complies with the following chemical and physical properties: (1) Boiling... requirements of § 151.50-30 for compressed gases are also applicable to the shipment of anhydrous ammonia...

Mid-IR spectra of different conformers of phenylalanine in the gas phase

NARCIS (Netherlands)

von Helden, G.; Compagnon, I.; Blom, M. N.; Frankowski, M.; Erlekam, U.; Oomens, J.; Brauer, B.; Gerber, R. B.; Meijer, G.

2008-01-01

The experimental mid- and far-IR spectra of six conformers of phenylalanine in the gas phase are presented. The experimental spectra are compared to spectra calculated at the B3LYP and at the MP2 level. The differences between B3LYP and MP2 IR spectra are found to be small. The agreement between

Resolving Phenylalanine Metabolism Sheds Light on Natural Synthesis of Penicillin G in Penicillium chrysogenum

NARCIS (Netherlands)

Veiga, T.; Solis-Escalante, D.; Romagnoli, G.; Ten Pierick, A.; Hanemaaijer, M.; Deshmuhk, A.; Wahl, A.; Pronk, J.T.; Daran, J.M.

2011-01-01

The industrial production of penicillin G by Penicillium chrysogenum requires the supplementation of the growth medium with the side chain precursor phenylacetate. The growth of P. chrysogenum with phenylalanine as the sole nitrogen source resulted in the extracellular production of phenylacetate

Synthesis of bradykinin labelled with tritium on the phenylalanine residue in position 5

International Nuclear Information System (INIS)

Seproedi, J.; Teplan, I.; Medzihradszky, K.

1976-01-01

The polypeptide hormone bradykinine, labelled with tritium in the phenylalanine chain in position 5, has been prepared. The preparation method is described; the tritium atom is incorporated in the last step of the synthesis. The hormone can therefore be labelled immediately before use, which avoids autoradiolysis during storage

Cationized phenylalanine conformations characterized by IRMPD and computation for singly and doubly charged ions

NARCIS (Netherlands)

Dunbar, R.C.; Steill, J.D.; Oomens, J.

2010-01-01

Electrospray ionization produces phenylalanine (Phe) complexes of the alkali metal ion series, plus Ag+ and Ba2+. Infrared multiple photon dissociation (IRMPD) spectroscopy using the FELIX free electron laser light source is used to characterize the conformations of the ions, in conjunction with

Comparison of ammonia emissions determined using different sampling methods

Science.gov (United States)

Dynamic, flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations; however, ammonia emissions from the surfaces are affected by many factors which can be affected by the chamber. Ammonia emissions estimated using environmental flow-through chambers may be...

46 CFR 98.25-5 - How anhydrous ammonia may be carried.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to be...

Ammonia-water Rankine cycle

International Nuclear Information System (INIS)

Bo Hanliang; Ma Changwen; Wu Shaorong

1997-01-01

On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

Effect of competing ions and causticization on the ammonia adsorption by a novel poly ligand exchanger (PLE) ammonia adsorption reagent.

Science.gov (United States)

Chen, Quanzhou; Zhou, Kanggen; Hu, Yuanjuan; Liu, Fang; Wang, Aihe

2017-03-01

In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin named ammonia adsorption reagent (AMAR), bearing the functional group of weak iminodiacetate acid, was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions. The effects of pH on the removal of ammonia by AMAR were investigated at 25 °C. The copper loaded on the resin forms a complex with NH 3 in solution under alkaline condition. The effect of alkaline dosage (AD) on the ammonia adsorption was investigated. The maximum breakthrough bed volumes were obtained when the AD was set as 0.75 mmol OH - /mL. The higher AD did not guarantee the better ammonia removal efficiency due to the forming of Cu(OH) 2 precipitate between OH - in solutions and Cu(II) on the resin. The effect of competing ions on the adsorption breakthrough curve of virgin AMAR and causticized AMAR was also investigated. The results demonstrated that the existence of competing ions had a negative impact on the adsorption capacity for both virgin AMAR and causticized AMAR. After causticization, the AMAR was more resistant to the competing ions comparing with virgin AMAR. The bivalent Ca 2+ affects the ammonia adsorption more than does the monovalent Na + .

Lipopolysaccharide impairs hepatocyte ureagenesis from ammonia: involvement of mitochondrial aquaporin-8.

Science.gov (United States)

Soria, Leandro R; Marrone, Julieta; Molinas, Sara M; Lehmann, Guillermo L; Calamita, Giuseppe; Marinelli, Raúl A

2014-05-02

We recently reported that hepatocyte mitochondrial aquaporin-8 (mtAQP8) channels facilitate the uptake of ammonia and its metabolism into urea. Here we studied the effect of bacterial lipopolysaccharides (LPS) on ammonia-derived ureagenesis. In LPS-treated rats, hepatic mtAQP8 protein expression and diffusional ammonia permeability (measured utilizing ammonia analogues) of liver inner mitochondrial membranes were downregulated. NMR studies using 15N-labeled ammonia indicated that basal and glucagon-induced ureagenesis from ammonia were significantly reduced in hepatocytes from LPS-treated rats. Our data suggest that hepatocyte mtAQP8-mediated ammonia removal via ureagenesis is impaired by LPS, a mechanism potentially relevant to the molecular pathogenesis of defective hepatic ammonia detoxification in sepsis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon.

Science.gov (United States)

Xue, Runmiao; Donovan, Ariel; Zhang, Haiting; Ma, Yinfa; Adams, Craig; Yang, John; Hua, Bin; Inniss, Enos; Eichholz, Todd; Shi, Honglan

2018-02-01

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products (DBPs) may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes. The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon (PAC) sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than 67% ammonia and 70%-100% N-nitrosamine precursors were removed by Mordenite zeolite (except 3-(dimethylaminomethyl)indole (DMAI) and 4-dimethylaminoantipyrine (DMAP)). PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors (dimethylamine (DMA), ethylmethylamine (EMA), diethylamine (DEA), dipropylamine (DPA), trimethylamine (TMA), DMAP, and DMAI) during the alum coagulation process. Copyright © 2017. Published by Elsevier B.V.

Ammonia pollution characteristics of centralized drinking water sources in China.

Science.gov (United States)

Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming

2012-01-01

The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

Science.gov (United States)

Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

2015-12-01

Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

Ammonia causes decreased brain monoamines in fathead minnows (Pimephales promelas)

Science.gov (United States)

Ronan, Patrick J.; Gaikowski, Mark P.; Hamilton, Steven J.; Buhl, Kevin J.; Summers, Cliff H.

2007-01-01

Hyperammonemia, arising from variety of disorders, leads to severe neurological dysfunction. The mechanisms of ammonia toxicity in brain are not completely understood. This study investigated the effects of ammonia on monoaminergic systems in brains of fathead minnows (Pimephales promelas). Fish serve as a good model system to investigate hyperammonemic effects on brain function since no liver manipulations are necessary to increase endogenous ammonia concentrations. Using high performance liquid chromatography with electrochemical detection, monoamines and some associated metabolites were measured from whole brain homogenate. Adult males were exposed for 48 h to six different concentrations of ammonia (0.01–2.36 mg/l unionized) which bracketed the 96-h LC50 for this species. Ammonia concentration-dependent decreases were found for the catecholamines (norepinephrine and dopamine) and the indoleamine serotonin (5-HT). After an initial increase in the 5-HT precursor 5-hydroxytryptophan it too decreased with increasing ammonia concentrations. There were also significant increases in the 5-HIAA/5-HT and DOPAC/DA ratios, often used as measures of turnover. There were no changes in epinephrine (Epi) or monoamine catabolites (DOPAC, 5-HIAA) at any ammonia concentrations tested. Results suggest that ammonia causes decreased synthesis while also causing increased release and degradation. Increased release may underlie behavioral reactions to ammonia exposure in fish. This study adds weight to a growing body of evidence demonstrating that ammonia leads to dysfunctional monoaminergic systems in brain which may underlie neurological symptoms associated with human disorders such as hepatic encephalopathy.

Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

2002-01-01

Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

Ammonia-based feedforward and feedback aeration control in activated sludge processes.

Science.gov (United States)

Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

2014-01-01

Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

ORTHO-TO-PARA ABUNDANCE RATIO (OPR) OF AMMONIA IN 15 COMETS: OPRs OF AMMONIA VERSUS 14N/15N RATIOS IN CN

International Nuclear Information System (INIS)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi; Jehin, Emmanuel; Manfroid, Jean; Hutsemekers, Damien; Arpigny, Claude

2011-01-01

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices. We present OPRs of ammonia (NH 3 ) in 15 comets based on optical high-dispersion spectroscopic observations of NH 2 , which is a photodissociation product of ammonia in the gaseous coma. The observations were mainly carried out with the VLT/UVES. The OPR of ammonia is estimated from the OPR of NH 2 based on the observations of the NH 2 (0, 9, 0) vibronic band. The absorption lines by the telluric atmosphere are corrected and the cometary C 2 emission lines blended with NH 2 lines are removed in our analysis. The ammonia OPRs show a cluster between 1.1 and 1.2 (this corresponds to a nuclear spin temperature of ∼30 K) for all comets in our sample except for 73P/Schwassmann-Wachmann 3 (73P/SW3). Comet 73P/SW3 (both B- and C-fragments) shows the OPR of ammonia consistent with nuclear spin statistical weight ratio (1.0) that indicates a high-temperature limit as nuclear spin temperature. We compared the ammonia OPRs with other properties ( 14 N/ 15 N ratios in CN, D/H ratios of water, and mixing ratios of volatiles). Comet 73P/SW3 is clearly different from the other comets in the plot of ammonia OPRs versus 14 N/ 15 N ratios in CN. The ammonia OPRs of 1.0 and lower 15 N-fractionation of CN in comet 73P/SW3 imply that icy materials in this comet formed under warmer conditions than other comets. Comets may be classified into two groups in the plot of ammonia OPRs against 14 N/ 15 N ratios in CN.

Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

Science.gov (United States)

Chew, S F; Ip, Y K

2014-03-01

With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

Ammonia in the environment: From ancient times to the present

International Nuclear Information System (INIS)

Sutton, Mark A.; Erisman, Jan Willem; Dentener, Frank; Moeller, Detlev

2008-01-01

Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority. - Past ammonia applications reveal new emphases in biospheric transformations

Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

Science.gov (United States)

Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

2016-01-01

Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

Closing CO2 Loop in Biogas Production: Recycling Ammonia As Fertilizer.

Science.gov (United States)

He, Qingyao; Yu, Ge; Tu, Te; Yan, Shuiping; Zhang, Yanlin; Zhao, Shuaifei

2017-08-01

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions. The ammonia removal efficiency in vacuum membrane distillation is around 75% regardless of the ammonia concentration of the biogas slurry. The recovered ammonia is used for CO 2 absorption to realize simultaneous biogas upgrading and fertilizer generation. CO 2 absorption performance of the recovered ammonia (absorption capacity and rate) is compared with a conventional model absorbent. Theoretical results on biogas upgrading are also provided. After ammonia recovery, the treated biogas slurry has significantly reduced phytotoxicity, improving the applicability for agricultural irrigation. The novel concept demonstrated in this study shows great potential in closing the CO 2 loop in biogas production by recycling ammonia as an absorbent for CO 2 absorption associated with producing fertilizers.

Room temperature ammonia and VOC sensing properties of CuO nanorods

International Nuclear Information System (INIS)

Bhuvaneshwari, S.; Gopalakrishnan, N.

2016-01-01

Here, we report a NH 3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

Room temperature ammonia and VOC sensing properties of CuO nanorods

Science.gov (United States)

Bhuvaneshwari, S.; Gopalakrishnan, N.

2016-05-01

Here, we report a NH3 and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

Room temperature ammonia and VOC sensing properties of CuO nanorods

Energy Technology Data Exchange (ETDEWEB)

Bhuvaneshwari, S.; Gopalakrishnan, N., E-mail: ngk@nitt.edu [Thin film laboratory, National Institute of Technology, Tiruchirappalli-620015 (India)

2016-05-23

Here, we report a NH{sub 3} and Volatile Organic Compounds (VOCs) sensing prototype of CuO nanorods with peculiar sensing characteristics at room temperature. High quality polycrystalline nanorods were synthesized by a low temperature hydrothermal method. The rods are well oriented with an aspect ratio of 5.71. Luminescence spectrum of CuO nanorods exhibited a strong UV-emission around 415 nm (2.98 eV) which arises from the electron-hole recombination phenomenon. The absence of further deep level emissions establishes the lack of defects such as oxygen vacancies and Cu interstitials. At room temperature, the sensor response was recorded over a range of gas concentrations from 100-600 ppm of ammonia, ethanol and methanol. The sensor response showed power law dependence with the gas concentration. This low temperature sensing can be validated by the lower value of calculated activation energy of 1.65 eV observed from the temperature dependent conductivity measurement.

Roles of renal ammonia metabolism other than in acid-base homeostasis.

Science.gov (United States)

Weiner, I David

2017-06-01

The importance of renal ammonia metabolism in acid-base homeostasis is well known. However, the effects of renal ammonia metabolism other than in acid-base homeostasis are not as widely recognized. First, ammonia differs from almost all other solutes in the urine in that it does not result from arterial delivery. Instead, ammonia is produced by the kidney, and only a portion of the ammonia produced is excreted in the urine, with the remainder returned to the systemic circulation through the renal veins. In normal individuals, systemic ammonia addition is metabolized efficiently by the liver, but in patients with either acute or chronic liver disease, conditions that increase the addition of ammonia of renal origin to the systemic circulation can result in precipitation and/or worsening of hyperammonemia. Second, ammonia appears to serve as an intrarenal paracrine signaling molecule. Hypokalemia increases proximal tubule ammonia production and secretion as well as reabsorption in the thick ascending limb of the loop of Henle, thereby increasing delivery to the renal interstitium and the collecting duct. In the collecting duct, ammonia decreases potassium secretion and stimulates potassium reabsorption, thereby decreasing urinary potassium excretion and enabling feedback correction of the initiating hypokalemia. Finally, the stimulation of renal ammonia metabolism by hypokalemia may contribute to the development of metabolic alkalosis, which in turn can stimulate NaCl reabsorption and contribute to the intravascular volume expansion, increased blood pressure and diuretic resistance that can develop with hypokalemia. The evidence supporting these novel non-acid-base roles of renal ammonia metabolism is discussed in this review.

Recombinant Programming

OpenAIRE

Pawlak , Renaud; Cuesta , Carlos; Younessi , Houman

2004-01-01

This research report presents a promising new approach to computation called Recombinant Programming. The novelty of our approach is that it separates the program into two layers of computation: the recombination and the interpretation layer. The recombination layer takes sequences as inputs and allows the programmer to recombine these sequences through the definition of cohesive code units called extensions. The output of such recombination is a mesh that can be used by the interpretation la...

Ammonia emissions in Europe

DEFF Research Database (Denmark)

Jacobsen, Brian H.

2012-01-01

The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

Bioactive Phenylalanine Derivatives and Cytochalasins from the Soft Coral-Derived Fungus, Aspergillus elegans

Directory of Open Access Journals (Sweden)

Xue-Ping Sun

2013-06-01

Full Text Available One new phenylalanine derivative 4′-OMe-asperphenamate (1, along with one known phenylalanine derivative (2 and two new cytochalasins, aspochalasin A1 (3 and cytochalasin Z24 (4, as well as eight known cytochalasin analogues (5–12 were isolated from the fermentation broth of Aspergillus elegans ZJ-2008010, a fungus obtained from a soft coral Sarcophyton sp. collected from the South China Sea. Their structures and the relative configurations were elucidated using comprehensive spectroscopic methods. The absolute configuration of 1 was determined by chemical synthesis and Marfey’s method. All isolated metabolites (1–12 were evaluated for their antifouling and antibacterial activities. Cytochalasins 5, 6, 8 and 9 showed strong antifouling activity against the larval settlement of the barnacle Balanus amphitrite, with the EC50 values ranging from 6.2 to 37 μM. This is the first report of antifouling activity for this class of metabolites. Additionally, 8 exhibited a broad spectrum of antibacterial activity, especially against four pathogenic bacteria Staphylococcus albus, S. aureus, Escherichia coli and Bacillus cereus.

Basic Physical Properties of Ammonia-Rich Ice

Science.gov (United States)

Shandera, S. E.; Lorenz, R. D.

2000-10-01

We report simple measurements of the thermal conductivity, mechanical strength and microwave absorptivity of ammonia hydrate ices, which are likely to be abundant in the Saturnian system. Understanding the dielectric properties of ammonia ice could play an important role in interpreting data from the Cassini spacecraft, which will image Titan's surface by radar in 2004. Thermal conductivity measurements were made by freezing a thin copper wire in the center of ice samples. The wire acted as both heater and temperature sensor, calibrated by a thermocouple also frozen in the sample. Ices with concentrations of 5- 30% ammonia were compared to pure water ice and ices containing salts. Thermal conductivity was found to decrease with increasing concentration of ammonia - a factor of 3 or 4 less than pure water ice for the 30% peritectic composition. Microwave absorptivity was measured by placing insulated ice samples and calibration materials in a conventional microwave oven. The microwave absorptivity was found to increase with increasing concentration of ammonia, although the effect is strongly temperature dependent, and heat leak from the room made quantitative measurement difficult. Mechanical strength was estimated using a ball bearing/accelerometer indentation method. For temperatures 100-150K, ammonia-rich ice has a Young's modulus about 10x smaller than pure ice. These properties affect tidal dissipation and the likelihood and style of cryovolcanism on (and the radar appearance of) the icy satellites and Titan. This work was supported by the Cassini RADAR team and the Arizona Space Grant Consortium.

A Pervaporation Study of Ammonia Solutions Using Molecular Sieve Silica Membranes

Directory of Open Access Journals (Sweden)

Xing Yang

2014-02-01

Full Text Available An innovative concept is proposed to recover ammonia from industrial wastewater using a molecular sieve silica membrane in pervaporation (PV, benchmarked against vacuum membrane distillation (VMD. Cobalt and iron doped molecular sieve silica-based ceramic membranes were evaluated based on the ammonia concentration factor downstream and long-term performance. A modified low-temperature membrane evaluation system was utilized, featuring the ability to capture and measure ammonia in the permeate. It was found that the silica membrane with confirmed molecular sieving features had higher water selectivity over ammonia. This was due to a size selectivity mechanism that favoured water, but blocked ammonia. However, a cobalt doped silica membrane previously treated with high temperature water solutions demonstrated extraordinary preference towards ammonia by achieving up to a 50,000 mg/L ammonia concentration (a reusable concentration level measured in the permeate when fed with 800 mg/L of ammonia solution. This exceeded the concentration factor expected by the benchmark VMD process by four-fold, suspected to be due to the competitive adsorption of ammonia over water into the silica structure with pores now large enough to accommodate ammonia. However, this membrane showed a gradual decline in selectivity, suspected to be due to the degradation of the silica material/pore structure after several hours of operation.

Plasmophore sensitized imaging of ammonia release from biological tissues using optodes

International Nuclear Information System (INIS)

Stroemberg, Niklas; Hakonen, Aron

2011-01-01

Highlights: → A plasmophore sensitized optode for imaging ammonia (NH 3 ) concentrations in muscle tissues was developed. → Ammonia concentrations ranging from 10 nM and upwards can be quantified reversibly with an optical resolution of 127 μm. → The general sensing scheme offers new possibilities for the development of artificial optical noses and tongues. - Abstract: A plasmophore sensitized optode was developed for imaging ammonia (NH 3 ) concentrations in muscle tissues. The developed ammonia sensor and an equivalent non plasmophore version of the sensor were tested side by side to compare their limit of detection, dynamic range, reversibility and overall imaging quality. Bio-degradation patterns of ammonia release from lean porcine skeletal muscle were studied over a period of 11 days. We demonstrate that ammonia concentrations ranging from 10 nM can be quantified reversibly with an optical resolution of 127 μm in a sample area of 25 mm x 35 mm. The plasmophore ammonia optode showed improved reversibility, less false pixels and a 2 nM ammonia detection limit compared to 200 nM for the non-plasmophore sensor. Main principles of the sensing mechanism include ammonia transfer over a gas permeable film, ammonia protonation, nonactin facilitated merocyanine-ammonium coextraction and plasmophore enhancement. The vast signal improvement is suggested to rely on solvatochroism, nanoparticle scattering and plasmonic interactions that are utilized constructively in a fluorescence ratio. In addition to fundamental medicinal and biological research applications in tissue physiology, reversible ammonia quantification will be possible for a majority of demanding imaging and non imaging applications such as monitoring of low ammonia background concentrations in air and non-invasive medicinal diagnosis through medical breath or saliva analysis. The nanoparticle doped sensor constitutes a highly competitive technique for ammonia sensing in complex matrixes and the

Operation experience with elevated ammonia

International Nuclear Information System (INIS)

Vankova, Katerina; Kysela, Jan; Malac, Miroslav; Petrecky, Igor; Svarc, Vladimir

2011-01-01

The 10 VVER units in the Czech and Slovak Republics are all in very good water chemistry and radiation condition, yet questions have arisen regarding the optimization of cycle chemistry and improved operation in these units. To address these issues, a comprehensive experimental program for different water chemistries of the primary circuit was carried out at the Rez Nuclear Research Institute, Czech Republic, with the goal of judging the influence of various water chemistries on radiation build-up. Four types of water chemistries were compared: standard VVER water chemistry (in common use), direct hydrogen dosing without ammonia, standard VVER water chemistry with elevated ammonia levels, and zinc dosing to standard VVER water chemistry. The test results showed that the types of water chemistry other than the common one have benefits for the operation of the nuclear power plant (NPP) primary circuit. Operation experience with elevated ammonia at NPP Dukovany Units 3 and 4 is presented which validates the experimental results, demonstrating improved corrosion product volume activity. (orig.)

Method for releasing hydrogen from ammonia borane

Science.gov (United States)

Varma, Arvind; Diwan, Moiz; Shafirovich, Evgeny; Hwang, Hyun-Tae; Al-Kukhun, Ahmad

2013-02-19

A method of releasing hydrogen from ammonia borane is disclosed. The method comprises heating an aqueous ammonia borane solution to between about 80-135.degree. C. at between about 14.7 and 200 pounds per square inch absolute (psia) to release hydrogen by hydrothermolysis.

Ammonia transformation in a biotrickling air filter

DEFF Research Database (Denmark)

Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias

2007-01-01

A simple, tubular biotrickling filter was designed for optimal removal of ammonia and odour in ventilation air from a pig house. The removal and transformation of ammonia was studied in detail by analysis and modelling of chemical gradients through the filter. Good correspondence between measurem...

Antioxidant characterization and sensory evaluation during storage of ultraviolet-B light exposed baby carrots (abstract)

Science.gov (United States)

Baby carrot processing induces wounding stress activation of phenylalanine ammonia-lyase (PAL), enhancing its nutrient content by increasing synthesis of secondary metabolites. Ultraviolet-B (UV-B) exposure further promotes the formation of soluble phenolic compounds, significantly increasing antiox...

Phenolic compounds and related enzymes as determinants of sorghum for food use

NARCIS (Netherlands)

Dicko, M.H.; Gruppen, H.; Traore, A.S.; Voragen, A.G.J.; Berkel, van W.J.H.

2006-01-01

Phenolic compounds and related enzymes such as phenol biosynthesizing enzymes (phenylalanine ammonia lyase) and phenol catabolizing enzymes (polyphenol oxidase and peroxidase) are determinants for sorghum utilization as human food because they influence product properties during and after sorghum

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

Science.gov (United States)

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

SIRT5 regulation of ammonia-induced autophagy and mitophagy

Science.gov (United States)

Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

2015-01-01

In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism. PMID:25700560

REDUCING AMMONIA CONCENTRATIONS IN ATMOSPHERE AFTER ITS UNPLANNED RELEASE

Directory of Open Access Journals (Sweden)

L. V. Amelina

2017-08-01

Full Text Available Purpose. The aim of this work is development of numerical model, which allows to calculate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia emission at the territory of ammonia pump station. The numerical model should allow fast calculating, taking into account the meteorological parameters and buildings situated near the source of toxic chemical emission and equipment for neutralizer supply. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. To simulate the chemical interaction between ammonia and neutralizer the stoichiometry equation is used. Equation of potential flow is used to compute flow pattern among buildings. To solve the equation for potential flow the Samarskii implicit difference scheme is used. The implicit change-triangle difference scheme is used to solve equation of mass transfer. While for the numerical integration the authors use the rectangular difference grid. Method of porosity technique («markers method» is applied to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of ammonia and neutralizer in the atmosphere, as well as the influence of buildings on admixture dispersion. On the basis of the developed numerical models the authors carried out a computational experiment to estimate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows calculating the flow pattern among buildings and estimating the efficiency of neutralizer supply for reduction of air pollution in the case unplanned ammonia release. Practical value. Model allows performing fast

Radiation Chemistry in Ammonia-Water Ices

Science.gov (United States)

Loeffler, M. J.; Raut, U.; Baragiola, R. A.

2010-01-01

We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

Recombiner

International Nuclear Information System (INIS)

Kikuchi, Nobuo.

1983-01-01

Purpose: To shorten the pre-heating time for a recombiner and obtain a uniform temperature distribution for the charged catalyst layer in a BWR type reactor. Constitution: A pre-heating heater is disposed to the outer periphery of a vessel for a recombiner packed with catalysts for recombining hydrogen and oxygen in gases flowing through a radioactive gaseous wastes processing system. Heat pipes for transmitting the heat applied to said container to the catalyst are disposed vertically and horizontally within the container. Different length of the heat pipes are combined. In this way, pre-heating time for the recombiner before the operation start and before the system switching can be shortened and the uniform pre-heating for the inside of the recombiner is also made possible. Further, heater control in the pre-heating can be carried out effectively and with ease. (Moriyama, K.)

Electrochemical monitoring of ammonia during anaerobic digestion

DEFF Research Database (Denmark)

Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

Ammonia is known as key inhibitor to methanogens in anaerobic digestion (AD) process. It’s of importance to develop efficient tool for ammonia monitoring. In this study, an electrolysis cell (EC) coupled with a complete nitrification reactor was developed as sensor for real time and online monito...

Catalytic Organometallic Reactions of Ammonia

Science.gov (United States)

Klinkenberg, Jessica L.

2012-01-01

Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

Removal of ammonia solutions used in catalytic wet oxidation processes.

Science.gov (United States)

Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

2003-08-01

Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

Nitrocarburizing in ammonia-hydrocarbon gas mixtures

DEFF Research Database (Denmark)

Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

2011-01-01

The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

Ammonia removal via microbial fuel cell (MFC) dynamic reactor

Science.gov (United States)

Alabiad, I.; Ali, U. F. M.; Zakarya, I. A.; Ibrahim, N.; Radzi, R. W.; Zulkurnai, N. Z.; Azmi, N. H.

2017-06-01

Landfill leachate is generally known as high-strength wastewater that is difficult to handle and contains dissolved extracts and suspended matter. Microbial fuel cells (MFCs) were designed to treat landfill leachate while continuously producing power (voltage output). Three different anodes were tested in MFC reactors: carbon black, activated carbon, and zinc electrodes. Movements in the MFC reactor during treatment were also a key factor for testing. Results showed a difference in ammonia levels in the three anodes used. The study compared the efficiency of static and dynamic modes of MFC in removing ammonia. Continual leachate movement in the reactor could increase the rate of removal of the ammonia components. The setup provided a viable condition for maximum removal because the reactor movement caused the sludge to disintegrate, which allowed ammonia to separate easily from the parent leachate. Ammonia removal also resulted from the transfer of ammonium through the membrane or from ammonia loss. Constant exchange of ionic content benefited the MFC performance by increasing power production and decreasing internal electrode material resistance. This paper presents the results of the analyses of leachate treatment from the solid waste landfill located in Padang Siding Landfill, Perlis. The performance of ammonia removal was enhanced using different types of electrodes. In both modes, activated carbon performed better than black carbon and zinc. The respective percentages of ammonia removal for activated carbon of dynamic over static were 96.6%, 66.6%, and 92.8% for activated carbon, zinc, and black carbon. The results provide further information on the possibility of using MFCs in landfill leachate treatment systems.

Adsorption of Ammonia on Regenerable Carbon Sorbents

Science.gov (United States)

Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

2015-01-01

Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

Mass transfer of ammonia escape and CO2 absorption in CO2 capture using ammonia solution in bubbling reactor

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Han, Tingting; Yu, Weijing

2016-01-01

Highlights: • Mass transfer coefficient models of ammonia escape were built. • Influences of temperature, inlet CO 2 and ammonia concentration were studied. • Mass transfer coefficients of ammonia escape and CO 2 absorption were obtained. • Studies can provide the basic data as a reference guideline for process application. - Abstract: The mass transfer of CO 2 capture using ammonia solution in the bubbling reactor was studied; according to double film theory, the mass transfer coefficient models and interface area model were built. Through our experiments, the overall volumetric mass transfer coefficients were obtained, while the interface areas in unit volume were estimated. The volumetric mass transfer coefficients of ammonia escaping during the experiment were 1.39 × 10 −5 –4.34 × 10 −5 mol/(m 3 s Pa), and the volumetric mass transfer coefficients of CO 2 absorption were 2.86 × 10 −5 –17.9 × 10 −5 mol/(m 3 s Pa). The estimated interface area of unit volume in the bubbling reactor ranged from 75.19 to 256.41 m 2 /m 3 , making the bubbling reactor a viable choice to obtain higher mass transfer performance than the packed tower or spraying tower.

New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

DEFF Research Database (Denmark)

Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

2002-01-01

Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

Cerebral ammonia uptake and accumulation during prolonged exercise in humans

DEFF Research Database (Denmark)

Nybo, Lars; Dalsgaard, Mads K.; Steensberg, Adam

2005-01-01

We evaluated whether peripheral ammonia production during prolonged exercise enhances the uptake and subsequent accumulation of ammonia within the brain. Two studies determined the cerebral uptake of ammonia (arterial and jugular venous blood sampling combined with Kety-Schmidt-determined cerebral...... blood flow; n = 5) and the ammonia concentration in the cerebrospinal fluid (CSF; n = 8) at rest and immediately following prolonged exercise either with or without glucose supplementation. There was a net balance of ammonia across the brain at rest and at 30 min of exercise, whereas 3 h of exercise...... exercise with glucose, and further to 16.1 ± 3.3 µM after the placebo trial (P

Effects of germination on the activities of amylases and phenolic enzymes in sorghum varieties grouped according to food end-use properties

NARCIS (Netherlands)

Dicko, M.H.; Gruppen, H.; Zouzouho, O.C.; Traore, A.S.; Berkel, van W.J.H.; Voragen, A.G.J.

2006-01-01

Fifty sorghum varieties were screened to determine the effects of germination on levels of starch, -amylase, -amylase, phenylalanine ammonia lyase (PAL), peroxidase (POX) and polyphenol oxidase (PPO). Germination decreased starch content, with amylose being more degraded than amylopectin. In

Hydrolyses of alpha-naphthyl acetate, beta-naphthyl acetate, and acetyl-DL-phenylalanine beta-naphthyl ester

DEFF Research Database (Denmark)

Kirkeby, S; Moe, D

1983-01-01

Using simultaneous coupling azo dye techniques kidney enzymes active against alpha-naphthyl acetate, beta-naphthyl acetate, and acetyl-DL-phenylalanine beta-naphthyl ester are characterized. The enzymes show identical distribution in the section. The banding patterns in zymograms are the same after...

40 CFR 418.20 - Applicability; description of the ammonia subcategory.

Science.gov (United States)

2010-07-01

... ammonia subcategory. 418.20 Section 418.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Ammonia Subcategory § 418.20 Applicability; description of the ammonia subcategory. The provisions of this subpart are...

Ammonia levels and the severity of hepatic encephalopathy

International Nuclear Information System (INIS)

Qureshi, M.O.; Khokhar, N.; Shafqat, F.

2014-01-01

Objective: To evaluate the correlation between ammonia levels with the severity of HE in patients coming to the tertiary care hospital with liver cirrhosis and hepatic encephalopathy (HE). Study Design: Descriptive, analytical study. Place and Duration of Study: Shifa International Hospital, Islamabad, from January 2011 to February 2012. Methodology: A total of 135 patients with liver cirrhosis and HE had serum ammonia levels measured on admission. The diagnosis of HE was based on clinical criteria, and its severity was graded according to the West Haven Criteria for grading of mental status. Ammonia levels were correlated with the severity of HE using Spearman rank correlation. Results: Out of 20 patients with normal ammonia levels, 13 (65%) were in HE I-II, 6 (30%) were in grade-III, while 1 (5%) patient was in grade-IV HE. Out of 45 patients with mild hyperammonemia, 27 (60%) were in grade I-II, 12 (26%) were in grade-III and 6 (13%) were in grade-IV HE. Out of 34 patients with moderate hyperammonemia, 9 (26%) were in grade I-II, 18 (53%) were in grade-III, and 7 (20%) were in grade-IV HE. Out of 36 patients with severe hyperammonemia, 31 (86%) patients were in grade-IV HE (p < 0.001). Conclusion: Ammonia levels correlated with the severity of hepatic encephalopathy. Greater the ammonia level, severe is the grade of hepatic encephalopathy. (author)

Thermodynamic Model for the Ammonia-Water System

DEFF Research Database (Denmark)

Thomsen, Kaj; Rasmussen, Peter

2000-01-01

The ammonia-water system is described by the Extended UNIQUAC model, which is an electrolyte model, formed by combining the original UNIQUAC model, the Debye-Hückel law and the Soave-Redlich-Kwong equation of state. The model is limited to temperatures below the critical temperature of ammonia. V...

Chilled ammonia process for CO2 capture

DEFF Research Database (Denmark)

Darde, Victor Camille Alfred; Thomsen, Kaj; van Well, Willy J. M

2009-01-01

The chilled ammonia process absorbs the CO2 at low temperature (2-10 degrees C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows...

Ammonia Concentrations in Different Aquaculture Holding Tanks ...

African Journals Online (AJOL)

High unionized ammonia recorded in the collapsible and concrete ponds was from excretion of high protein rich feed, decomposition of uneaten feed, high stocking density, low water exchange rates, water source and the alkaline medium of the systems. Low unionized ammonia in earthen pond and natural pond was ...

Calculation notes in support of ammonia releases from waste tank ventilation systems

International Nuclear Information System (INIS)

Wojdac, L.F.

1996-01-01

Ammonia is generated in waste tanks via the degradation of nitrogen compounds. The ammonia is released from the liquids by a mechanism which is dependent on temperature, pH, ionic strength and ammonia concentration. The release of ammonia to the environment occurs via diffusion of ammonia through a stagnant air mass and into the ventilation system

Metabolic recycling of ammonia via glutamate dehydrogenase supports breast cancer biomass.

Science.gov (United States)

Spinelli, Jessica B; Yoon, Haejin; Ringel, Alison E; Jeanfavre, Sarah; Clish, Clary B; Haigis, Marcia C

2017-11-17

Ammonia is a ubiquitous by-product of cellular metabolism; however, the biological consequences of ammonia production are not fully understood, especially in cancer. We found that ammonia is not merely a toxic waste product but is recycled into central amino acid metabolism to maximize nitrogen utilization. In our experiments, human breast cancer cells primarily assimilated ammonia through reductive amination catalyzed by glutamate dehydrogenase (GDH); secondary reactions enabled other amino acids, such as proline and aspartate, to directly acquire this nitrogen. Metabolic recycling of ammonia accelerated proliferation of breast cancer. In mice, ammonia accumulated in the tumor microenvironment and was used directly to generate amino acids through GDH activity. These data show that ammonia is not only a secreted waste product but also a fundamental nitrogen source that can support tumor biomass. Copyright © 2017, American Association for the Advancement of Science.

Ammonia removal in electrochemical oxidation: Mechanism and pseudo-kinetics

International Nuclear Information System (INIS)

Li Liang; Liu Yan

2009-01-01

This paper investigated the mechanism and pseudo-kinetics for removal of ammonia by electrochemical oxidation with RuO 2 /Ti anode using batch tests. The results show that the ammonia oxidation rates resulted from direct oxidation at electrode-liquid interfaces of the anode by stepwise dehydrogenation, and from indirect oxidation by hydroxyl radicals were so slow that their contribution to ammonia removal was negligible under the condition with Cl - . The oxidation rates of ammonia ranged from 1.0 to 12.3 mg N L -1 h -1 and efficiency reached nearly 100%, primarily due to the indirect oxidation of HOCl, and followed pseudo zero-order kinetics in electrochemical oxidation with Cl - . About 88% ammonia was removed from the solution. The removed one was subsequently found in the form of N 2 in the produced gas. The rate at which Cl - lost electrons at the anode was a major factor in the overall ammonia oxidation. Current density and Cl - concentration affected the constant of the pseudo zero-order kinetics, expressed by k = 0.0024[Cl - ] x j. The ammonia was reduced to less than 0.5 mg N L -1 after 2 h of electrochemical oxidation for the effluent from aerobic or anaerobic reactors which treated municipal wastewater. This result was in line with the strict discharge requirements

Effects of end-stage renal disease and dialysis modalities on blood ammonia level.

Science.gov (United States)

Vaziri, Nosratola D; Khazaeli, Mahyar; Nunes, Ane C F; Harley, Kevin T; Said, Hyder; Alipour, Omeed; Lau, Wei Ling; Pahl, Madeleine V

2017-07-01

Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. © 2016 International Society for Hemodialysis.

Pharmacological experiment of 13N-ammonia as PET imaging agent

International Nuclear Information System (INIS)

Wang Mingfang; Tang Ganghua; Gao Xiao; Li Zhi; Wu Hubing; Huang Zuhan; Jiang Hong; Zhong Jinmei; Wang Quanshi

2002-01-01

Objective: To study the pharmacological characteristics of 13 N-ammonia, the clinical PET imaging methods of 13 N-ammonia, and its application in myocardial blood flow perfusion. Methods: The uptakes of 13 N-ammonia in the myocardium and other organs in dogs were measured by whole body scanning and chest dynamic PET scanning. The regional myocardial blood flow (rMBF) in healthy volunteers was also measured by the dynamic and static PET imaging following intravenous bolus administration of 13 N-ammonia. Results: The heart and lungs were the first-pass organs that was found out by PET imaging with 13 N-ammonia in dogs and human volunteers, the highest uptake of 13 N-ammonia in the myocardium was also observed. At 30 s after injection the radioactivity in the blood pool of left and right ventricles reached its peak, at 1 min it began to drop, and at 4-20 min after injection the lower radioactivity was kept on. Regional analysis of PET imaging showed that the myocardial uptake of 13 N-ammonia began at 10 s after injection, and the uptake in the septum wall was higher than that in the lateral wall; but in the septum wall was slightly higher than in the lateral wall at 2 min after injection. The radioactivity in the liver and lungs reached its peak at 30 s and was sharply declined hereafter. The uptake of 13 N-ammonia in the liver and lungs remained at the lower levels and the heart-to-blood, heart-to-liver and heart-to-lung ratios were above 2.0 after 5 min. Whole-body PET scanning for dogs showed that 13 N-ammonia was distributed primarily in the organs with rich blood flow and its clearance was observed in the kidney. The images of regional myocardial blood flow (rMBF) acquired from the dynamic or static PET imaging following intravenous bolus administration of 13 N-ammonia were of no difference. Conclusions: The analysis of distribution of 13 N-ammonia indicates that the heart-to-blood, heart-to-liver and heat-to-lung ratios were high and the PET images were clear

Ammonia volatilization from crop residues and frozen green manure crops

Science.gov (United States)

de Ruijter, F. J.; Huijsmans, J. F. M.; Rutgers, B.

2010-09-01

Agricultural systems can lose substantial amounts of nitrogen (N). To protect the environment, the European Union (EU) has adopted several directives that set goals to limit N losses. National Emission Ceilings (NEC) are prescribed in the NEC directive for nitrogen oxides and ammonia. Crop residues may contribute to ammonia volatilization, but sufficient information on their contribution to the national ammonia volatilization is lacking. Experiments were carried out with the aim to assess the ammonia volatilization of crop residues left on the soil surface or incorporated into the soil under the conditions met in practice in the Netherlands during late autumn and winter. Ammonia emission from residues of broccoli, leek, sugar beet, cut grass, fodder radish (fresh and frozen) and yellow mustard (frozen) was studied during two winter seasons using volatilization chambers. Residues were either placed on top of soil or mixed with soil. Mixing residues with soil gave insignificant ammonia volatilization, whereas volatilization was 5-16 percent of the N content of residues when placed on top of soil. Ammonia volatilization started after at least 4 days. Total ammonia volatilization was related to C/N-ratio and N concentration of the plant material. After 37 days, cumulative ammonia volatilization was negligible from plant material with N concentration below 2 percent, and was 10 percent of the N content of plant material with 4 percent N. These observations can be explained by decomposition of plant material by micro-organisms. After an initial built up of the microbial population, NH 4+ that is not needed for their own growth is released and can easily emit as NH 3 at the soil surface. The results of the experiments were used to estimate the contribution of crop residues to ammonia volatilization in the Netherlands. Crop residues of arable crops and residues of pasture topping may contribute more than 3 million kg NH 3-N to the national ammonia volatilization of the

Ammonia synthesis at low temperatures

DEFF Research Database (Denmark)

Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

2000-01-01

have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics.......Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...

Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

International Nuclear Information System (INIS)

Marshall, T.R.

1995-01-01

Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

Advances in ammonia metabolism and hepatic encephalopathy

International Nuclear Information System (INIS)

Soeters, P.B.; Wilson, J.H.P.; Meijer, A.J.; Holm, E.

1988-01-01

There are four main 'parts' within the book: the first is devoted to peripheral and hepatic ammonia metabolism, the urea cycle, acid base status and its regulation; part two addresses animal models in liver failure, GABA-ergic neurotransmission and its relevance in hepatic failure; a third part concerns neurochemistry including brain ammonia metabolism, serotonin metabolism and energy status, in vivo evaluated with modern techniques like infusion of compounds labeled with stable or radioactive isotopes and with NMR, while the last section provides a description of the determination of ammonia and the treatment of encephalopathy with established but also with experimental techniques. refs.; figs.; tabs

Ice nucleation of ammonia gas exposed montmorillonite mineral dust particles

Directory of Open Access Journals (Sweden)

A. Salam

2007-07-01

Full Text Available The ice nucleation characteristics of montmorillonite mineral dust aerosols with and without exposure to ammonia gas were measured at different atmospheric temperatures and relative humidities with a continuous flow diffusion chamber. The montmorillonite particles were exposed to pure (100% and diluted ammonia gas (25 ppm at room temperature in a stainless steel chamber. There was no significant change in the mineral dust particle size distribution due to the ammonia gas exposure. 100% pure ammonia gas exposure enhanced the ice nucleating fraction of montmorillonite mineral dust particles 3 to 8 times at 90% relative humidity with respect to water (RHw and 5 to 8 times at 100% RHw for 120 min exposure time compared to unexposed montmorillonite within our experimental conditions. The percentages of active ice nuclei were 2 to 8 times higher at 90% RHw and 2 to 7 times higher at 100% RHw in 25 ppm ammonia exposed montmorillonite compared to unexposed montmorillonite. All montmorillonite particles are more efficient as ice nuclei with increasing relative humidities and decreasing temperatures. The activation temperature of montmorillonite exposed to 100% pure ammonia was 15°C higher than for unexposed montmorillonite particles at 90% RHw. In the 25 ppm ammonia exposed montmorillonite experiments, the activation temperature was 10°C warmer than unexposed montmorillonite at 90% RHw. Degassing does not reverse the ice nucleating ability of ammonia exposed montmorillonite mineral dust particles suggesting that the ammonia is chemically bound to the montmorillonite particle. This is the first experimental evidence that ammonia gas exposed montmorillonite mineral dust particles can enhance its activation as ice nuclei and that the activation can occur at temperatures warmer than –10°C where natural atmospheric ice nuclei are very scarce.

Ammonia modifies enteric neuromuscular transmission through glial γ-aminobutyric acid signaling.

Science.gov (United States)

Fried, David E; Watson, Ralph E; Robson, Simon C; Gulbransen, Brian D

2017-12-01

Impaired gut motility may contribute, at least in part, to the development of systemic hyperammonemia and systemic neurological disorders in inherited metabolic disorders, or in severe liver and renal disease. It is not known whether enteric neurotransmission regulates intestinal luminal and hence systemic ammonia levels by induced changes in motility. Here, we propose and test the hypothesis that ammonia acts through specific enteric circuits to influence gut motility. We tested our hypothesis by recording the effects of ammonia on neuromuscular transmission in tissue samples from mice, pigs, and humans and investigated specific mechanisms using novel mutant mice, selective drugs, cellular imaging, and enzyme-linked immunosorbent assays. Exogenous ammonia increased neurogenic contractions and decreased neurogenic relaxations in segments of mouse, pig, and human intestine. Enteric glial cells responded to ammonia with intracellular Ca 2+ responses. Inhibition of glutamine synthetase and the deletion of glial connexin-43 channels in hGFAP :: Cre ER T2+/- /connexin43 f/f mice potentiated the effects of ammonia on neuromuscular transmission. The effects of ammonia on neuromuscular transmission were blocked by GABA A receptor antagonists, and ammonia drove substantive GABA release as did the selective pharmacological activation of enteric glia in GFAP::hM3Dq transgenic mice. We propose a novel mechanism whereby local ammonia is operational through GABAergic glial signaling to influence enteric neuromuscular circuits that regulate intestinal motility. Therapeutic manipulation of these mechanisms may benefit a number of neurological, hepatic, and renal disorders manifesting hyperammonemia. NEW & NOTEWORTHY We propose that local circuits in the enteric nervous system sense and regulate intestinal ammonia. We show that ammonia modifies enteric neuromuscular transmission to increase motility in human, pig, and mouse intestine model systems. The mechanisms underlying the

Chilled Ammonia Process for CO2 Capture

DEFF Research Database (Denmark)

Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

2010-01-01

The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...

Physiological mechanism of resistance to anthracnose of different ...

African Journals Online (AJOL)

However, enzyme activity of resistant cultivars improved markedly after pathogen inoculation, while those of susceptible cultivars did not change. This study broadens the understanding of the mechanisms of disease resistance in Camellia. Keywords: Anthracnose, Camellia oleifera, phenylalanine ammonia lyase, ...

Calcium in the Mechanism of Ammonia-Induced Astrocyte Swelling

Science.gov (United States)

Jayakumar, A.R.; Rao, K.V. Rama; Tong, X.Y; Norenberg, M.D.

2016-01-01

Brain edema, due largely to astrocyte swelling, is an important clinical problem in patients with acute liver failure. While mechanisms underlying astrocyte swelling in this condition are not fully understood, ammonia and associated oxidative/nitrosative stress (ONS) appear to be involved. Mechanisms responsible for the increase in reactive oxygen/nitrogen species (RONS) and their role in ammonia-induced astrocyte swelling, however, are poorly understood. Recent studies have demonstrated a transient increase in intracellular Ca2+ in cultured astrocytes exposed to ammonia. As Ca2+ is a known inducer of RONS, we investigated potential mechanisms by which Ca2+ may be responsible for the production of RONS and cell swelling in cultured astrocytes after treatment with ammonia. Exposure of cultured astrocytes to ammonia (5 mM) increased the formation of free radicals, including nitric oxide, and such increase was significantly diminished by treatment with the Ca2+ chelator BAPTA-AM. We then examined the activity of Ca2+-dependent enzymes that are known to generate RONS and found that ammonia significantly increased the activities of NADPH oxidase (NOX), constitutive nitric oxide synthase (cNOS) and phospholipase A2 (PLA2) and such increases in activity were significantly diminished by BAPTA. Pretreatment of cultures with 7-nitroindazole, apocyanin and quinacrine, respective inhibitors of cNOS, NOX and PLA2, all significantly diminished RONS production. Additionally, treatment of cultures with BAPTA or with inhibitors of cNOS, NOX and PLA2 reduced ammonia-induced astrocyte swelling. These studies suggest that the ammonia-induced rise in intracellular Ca2+ activates free radical producing enzymes that ultimately contribute to the mechanism of astrocyte swelling. PMID:19393035

Removal of ammonia from tarry water using a tubular furnace

Energy Technology Data Exchange (ETDEWEB)

V.V. Grabko; V.A. Kofanova; V.M. Li; M.A. Solov' ev [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

2009-07-15

An ammonia-processing system without the use of live steam from OAO Alchevskkoks plant's supply network is considered. Steam obtained from the wastewater that leaves the ammonia column is used to process the excess tarry water, with the release of volatile ammonia.

Evaluation of the potential for significant ammonia releases from Hanford waste tanks

International Nuclear Information System (INIS)

Palmer, B.J.; Anderson, C.M.; Chen, G.; Cuta, J.M.; Ferryman, T.A.; Terrones, G.

1996-07-01

Ammonia is ubiquitous as a component of the waste stored in the Hanford Site single-shell tanks (SSTs) and double-shell tanks (DSTs). Because ammonia is both flammable and toxic, concerns have been raised about the amount of ammonia stored in the tanks and the possible mechanisms by which it could be released from the waste into the head space inside the tanks as well as into the surrounding atmosphere. Ammonia is a safety issue for three reasons. As already mentioned, ammonia is a flammable gas and may contribute to a flammability hazard either directly, if it reaches a high enough concentration in the tank head space, or by contributing to the flammability of other flammable gases such as hydrogen (LANL 1994). Ammonia is also toxic and at relatively low concentrations presents a hazard to human health. The level at which ammonia is considered Immediately Dangerous to Life or Health (IDLH) is 300 ppm (WHC 1993, 1995). Ammonia concentrations at or above this level have been measured inside the head space in a number of SSTs. Finally, unlike hydrogen and nitrous oxide, ammonia is highly soluble in aqueous solutions, and large amounts of ammonia can be stored in the waste as dissolved gas. Because of its high solubility, ammonia behaves in a qualitatively different manner from hydrogen or other insoluble gases. A broader range of scenarios must be considered in modeling ammonia storage and release

Impact Assessment and Environmental Evaluation of Various Ammonia Production Processes

Science.gov (United States)

Bicer, Yusuf; Dincer, Ibrahim; Vezina, Greg; Raso, Frank

2017-05-01

In the current study, conventional resources-based ammonia generation routes are comparatively studied through a comprehensive life cycle assessment. The selected ammonia generation options range from mostly used steam methane reforming to partial oxidation of heavy oil. The chosen ammonia synthesis process is the most common commercially available Haber-Bosch process. The essential energy input for the methods are used from various conventional resources such as coal, nuclear, natural gas and heavy oil. Using the life cycle assessment methodology, the environmental impacts of selected methods are identified and quantified from cradle to gate. The life cycle assessment outcomes of the conventional resources based ammonia production routes show that nuclear electrolysis-based ammonia generation method yields the lowest global warming and climate change impacts while the coal-based electrolysis options bring higher environmental problems. The calculated greenhouse gas emission from nuclear-based electrolysis is 0.48 kg CO2 equivalent while it is 13.6 kg CO2 per kg of ammonia for coal-based electrolysis method.

Novel ammonia sensor based on polyaniline/polylactic acid composite films

International Nuclear Information System (INIS)

Sotirov, S; Bodurov, I; Marudova, M

2017-01-01

We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al 2 O 3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected. (paper)

Novel ammonia sensor based on polyaniline/polylactic acid composite films

Science.gov (United States)

Sotirov, S.; Bodurov, I.; Marudova, M.

2017-01-01

We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al2O3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected.

Evaluation of an Adsorbent Based on Agricultural Waste (Corn Cobs for Removal of Tyrosine and Phenylalanine from Aqueous Solutions

Directory of Open Access Journals (Sweden)

Cibele C. O. Alves

2013-01-01

Full Text Available Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria. In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr from both a single component solution and a binary aqueous solution with phenylalanine (Phe. The adsorption behavior of tyrosine was similar to that of phenylalanine in single component solutions, however, with a much lower adsorption capacity (14 mg g−1 for Tyr compared to 109 mg g−1 for Phe. Tyr adsorption kinetics was satisfactorily described by a pseudosecond-order model as it was for Phe. In adsorption equilibrium studies for binary mixtures, the presence of Tyr in Phe solutions favored Phe faster adsorption whereas the opposite behavior was observed for the presence of Phe in Tyr solutions. Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.

Ammonia nanotubes and their interactions with coinage metals

Energy Technology Data Exchange (ETDEWEB)

Mohajeri, Afshan, E-mail: amohajeri@shirazu.ac.ir; Bozorgizadeh, Tahereh

2014-09-30

Highlights: • The possibility of building ammonia nanotubes (ANTs) is explored. • Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. • The interactions between the ANTs and coinage metals are investigated. • The nature of nitrogen–metal bonds is unveiled by quantum chemical approaches. - Abstract: The hydrogen bond networks of finite ammonia molecules are considered to explore the possibility of building ammonia nanotubes (ANTs). Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. The calculated stabilization energies indicate considerable stability for ANTs. In the second part, the interactions between the constructed ANTs and coinage metals (M = Cu, Ag, and Au) are investigated with a focus on the nature of nitrogen…metal bonds. The changes in binding energies from copper to gold reveal that the three metals have almost similar tendency for the interaction with ANTs and the interaction strength is governed by the structure of ANT. Furthermore, the electronic and structural properties of the resulting complexes have been unveiled by means of the quantum chemical analyses. The N…M bonds are found to have partially covalent and partially electrostatic nature.

Does ammonia trigger hyperventilation in the elasmobranch, Squalus acanthias suckleyi?

Science.gov (United States)

De Boeck, Gudrun; Wood, Chris M

2015-01-15

We examined the ventilatory response of the spiny dogfish, to elevated internal or environmental ammonia. Sharks were injected via arterial catheters with ammonia solutions or their Na salt equivalents sufficient to increase plasma total ammonia concentration [TAmm]a by 3-5 fold from 145±21μM to 447±150μM using NH4HCO3 and a maximum of 766±100μM using (NH4)2SO4. (NH4)2SO4 caused a small increase in ventilation frequency (+14%) and a large increase in amplitude (+69%), while Na2SO4 did not. However, CO2 partial pressure (PaCO2) also increased and arterial pHa and plasma bicarbonate concentration ([HCO3(-)]a) decreased. NH4HCO3 caused a smaller increase in plasma ammonia resulting in a smaller but significant, short lived increases in ventilation frequency (+6%) and amplitude (36%), together with a rise in PaCO2 and [HCO3(-)]a. Injection with NaHCO3 which increased pHa and [HCO3(-)]a did not change ventilation. Plasma ammonia concentration correlated significantly with ventilation amplitude, while ventilation frequency showed a (negative) correlation with pHa. Exposure to high environmental ammonia (1500μM NH4HCO3) did not induce changes in ventilation until plasma [TAmm]a increased and ventilation amplitude (but not frequency) increased in parallel. We conclude that internal ammonia stimulates ventilation in spiny dogfish, especially amplitude or stroke volume, while environmental ammonia only stimulates ventilation after ammonia diffuses into the bloodstream. Copyright © 2014 Elsevier B.V. All rights reserved.

Sustainable Ammonia Synthesis – Exploring the scientific challenges associated with discovering alternative, sustainable processes for ammonia production

Energy Technology Data Exchange (ETDEWEB)

Nørskov, Jens [Stanford Univ., CA (United States); ; SLAC National Accelerator Lab., Menlo Park, CA (United States); Chen, Jingguang [Columbia Univ., New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Miranda, Raul [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Fitzsimmons, Tim [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Stack, Robert [Dept. of Energy (DOE), Washington DC (United States). Office of Science

2016-02-18

Ammonia (NH₃) is essential to all life on our planet. Until about 100 years ago, NH₃ produced by reduction of dinitrogen (N₂) in air came almost exclusively from bacteria containing the enzyme nitrogenase.. DOE convened a roundtable of experts on February 18, 2016. Participants in the Roundtable discussions concluded that the scientific basis for sustainable processes for ammonia synthesis is currently lacking, and it needs to be enhanced substantially before it can form the foundation for alternative processes. The Roundtable Panel identified an overarching grand challenge and several additional scientific grand challenges and research opportunities: -Discovery of active, selective, scalable, long-lived catalysts for sustainable ammonia synthesis. -Development of relatively low pressure (<10 atm) and relatively low temperature (<200 C) thermal processes. -Integration of knowledge from nature (enzyme catalysis), molecular/homogeneous and heterogeneous catalysis. -Development of electrochemical and photochemical routes for N₂ reduction based on proton and electron transfer -Development of biochemical routes to N₂ reduction -Development of chemical looping (solar thermochemical) approaches -Identification of descriptors of catalytic activity using a combination of theory and experiments -Characterization of surface adsorbates and catalyst structures (chemical, physical and electronic) under conditions relevant to ammonia synthesis.

Biotreatment of ammonia and butanal containing waste gases

OpenAIRE

Weckhuysen, B.M.; Vriens, L.; Verachtert, H.

1994-01-01

Abstract The biological removal of ammonia and butanal in contaminated air was investigated by using, respectively, a laboratory-scale filter and a scrubber-filter combination. It was shown that ammonia can be removed with an elimination efficiency of 83% at a volumetric load of 100 m3·m–2·h–1 with 4–16 ppm of ammonia. During the experiment percolates were analysed for nitrate, nitrite, ammonium and pH. It was found that the nitrification in the biofilter could deteriorate due to an inhibitio...

The effect of gaseous ammonia on cobalt perrhenate

International Nuclear Information System (INIS)

Maslov, L.P.; Men'shikov, O.D.; Borisov, V.V.; Sorokin, S.I.; Krutovertsev, S.A.; Kharkevich, S.I.; Ivanova, O.M.

1994-01-01

The influence of humid air ammonia mixture on crystal pentahydrate of cobalt(2) perrhenate has been studied by the methods of PES, IR spectroscopy thermal analysis and electrophysical measurements. It is shown that with an increase in ammonia content in gaseous phase cobalt perrhenate successively transforms into diaquodiammine-, tetrammine- and μ-dioxo-bis-(tetrammine) derivatives of cobalt. Reversibility of dioxocomplex formation and a correlation between the change in electrophysical properties of crystal sample and change in ammonia content in gaseous phase are pointed out. 16 refs.; 4 figs.; 1 tab

Catalytic synthesis of ammonia using vibrationally excited nitrogen

DEFF Research Database (Denmark)

Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

1992-01-01

In a previous study we have considered the catalytic synthesis of ammonia in the presence of vibrationally excited nitrogen. The distribution over vibrational states was assumed to be maintained during the reaction, and it was shown that the yield of ammonia increased considerably compared...... to that from conventional synthesis. In the present study the nitrogen molecules are only excited at the inlet of a plug flow reactor, and the importance of vibrational relaxation is investigated. We show that vibrational excitation can give an enhanced yield of ammonia also in the situation where vibrational...

Methods of ammonia removal in anaerobic digestion: a review.

Science.gov (United States)

Krakat, Niclas; Demirel, Burak; Anjum, Reshma; Dietz, Donna

2017-10-01

The anaerobic digestion of substrates with high ammonia content has always been a bottleneck in the methanisation process of biomasses. Since microbial communities in anaerobic digesters are sensitive to free ammonia at certain conditions, the digestion of nitrogen-rich substrates such as livestock wastes may result in inhibition/toxicity eventually leading to process failures, unless appropriate engineering precautions are taken. There are many different options reported in literature to remove ammonia from anaerobic digesters to achieve a safe and stable process so that along with high methane yields, a good quality of effluents can also be obtained. Conventional techniques to remove ammonia include physical/chemical methods, immobilization and adaptation of microorganisms, while novel methods include ultrasonication, microwave, hollow fiber membranes and microbial fuel cell applications. This paper discusses conventional and novel methods of ammonia removal from anaerobic digesters using nitrogen-rich substrates, with particular focus on recent literature available about this topic.

Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

Science.gov (United States)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-03-01

In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

Ammonia concentration modeling based on retained gas sampler data

International Nuclear Information System (INIS)

Terrones, G.; Palmer, B.J.; Cuta, J.M.

1997-09-01

The vertical ammonia concentration distributions determined by the retained gas sampler (RGS) apparatus were modeled for double-shell tanks (DSTs) AW-101, AN-103, AN-104, and AN-105 and single-shell tanks (SSTs) A-101, S-106, and U-103. One the vertical transport of ammonia in the tanks were used for the modeling. Transport in the non-convective settled solids and floating solids layers is assumed to occur primarily via some type of diffusion process, while transport in the convective liquid layers is incorporated into the model via mass transfer coefficients based on empirical correlations. Mass transfer between the top of the waste and the tank headspace and the effects of ventilation of the headspace are also included in the models. The resulting models contain a large number of parameters, but many of them can be determined from known properties of the waste configuration or can be estimated within reasonable bounds from data on the waste samples themselves. The models are used to extract effective diffusion coefficients for transport in the nonconvective layers based on the measured values of ammonia from the RGS apparatus. The modeling indicates that the higher concentrations of ammonia seen in bubbles trapped inside the waste relative to the ammonia concentrations in the tank headspace can be explained by a combination of slow transport of ammonia via diffusion in the nonconvective layers and ventilation of the tank headspace by either passive or active means. Slow transport by diffusion causes a higher concentration of ammonia to build up deep within the waste until the concentration gradients between the interior and top of the waste are sufficient to allow ammonia to escape at the same rate at which it is being generated in the waste

Ammonia abundances in comets

Science.gov (United States)

Wyckoff, S.; Tegler, S.; Engel, L.

The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

ThermoEnergy Ammonia Recovery Process for Municipal and Agricultural Wastes

Directory of Open Access Journals (Sweden)

Alex G. Fassbender

2001-01-01

Full Text Available The Ammonia Recovery Process (ARP is an award-winning, low-cost, environmentally responsible method of recovering nitrogen, in the form of ammonia, from various dilute waste streams and converting it into concentrated ammonium sulfate. The ThermoEnergy Biogas System utilizes the new chemisorption-based ARP to recover ammonia from anaerobically digested wastes. The process provides for optimal biogas production and significantly reduced nitrogen levels in the treated water discharge. Process flows for the ammonia recovery and ThermoEnergy biogas processes are presented and discussed. A comparison with other techniques such as biological nitrogen removal is made. The ARP technology uses reversible chemisorption and double salt crystal precipitation to recover and concentrate the ammonia. The ARP technology was successfully proven in a recent large-scale field demonstration at New York City’s Oakwood Beach Wastewater Treatment Plant, located on Staten Island. This project was a joint effort with Foster Wheeler Environmental Corporation, the Civil Engineering Research Foundation, and New York City Department of Environmental Protection. Independent validated plant data show that ARP consistently recovers up to 99.9% of the ammonia from the city’s centrate waste stream (derived from dewatering of sewage sludge, as ammonium sulfate. ARP technology can reduce the nitrogen (ammonia discharged daily into local bodies of water by municipalities, concentrated animal farming operations, and industry. Recent advances to ARP enhance its performance and economic competitiveness in comparison to stripping or ammonia destruction technologies.

Techniques for measuring ammonia in fly ash, mortar, and concrete

Energy Technology Data Exchange (ETDEWEB)

Rathbone, R.F. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Reseach; Majors, R.K. [Boral Material Technologies, Inc., San Antonio, TX (United States). Engineered Materials

2003-12-01

The presence of ammonia in fly ash that is to be used in mortar and concrete is of increasing concern in the U.S., mainly due to the installation of selective catalytic reduction (SCR) DeNOx systems. When the SCR catalyst is new, contamination of the fly ash with ammonia is generally not a concern. However, as the catalyst in the SCR ages and becomes less efficient, the ammonia slip increases and results in a greater amount of ammonium salt being precipitated on the fly ash. The increase in ammonia concentration is compounded by variability that can occur on a day-to-day basis. When marketing ammonia-laden fly ash for use in mortar and concrete it is imperative that the concentration of ammonia is known. However, there currently is no widely accepted or ''standard'' method for ammonia measurement in fly ash. This paper describes two methods that have been developed and used by the University of Kentucky Center for Applied Energy Research and Boral Material Technologies, Inc. One of the methods uses gas detection tubes and can provide an accurate determination within five to ten minutes. Thus it is suitable as a rapid field technique. The other method employs a gas-sensing electrode and requires a longer period of time to complete the measurement. However, this second method can also be used to determine the quantity of ammonia in fresh mortar and concrete. (orig.)

Metabolic fate of 13N-labeled ammonia in rat brain

International Nuclear Information System (INIS)

Cooper, A.J.L.; McDonald, J.M.; Gelbard, A.S.; Gledhill, R.F.; Duffy, T.E.

1979-01-01

After infusion of physiological concentrations of [ 13 N]ammonia for 10 min via one internal carotid artery, the relative specific activities of glutamate, glutamine (α-amino), and glutamine (amide) in rat brain were approximately 1:5:400, respectively. Analysis of metabolites, after infusion of [ 13 N]ammonia into one lateral cerebral ventricle, indicated that ammonia entering the brain from the cerebrospinal fluid is also metabolized in a small glutamate pool. Pretreatment with methionine sulfoximine led to a decrease in the label present in brain glutamine following carotid artery infusion of [ 13 N]ammonia. 13 N activity in brain glutamate was greater than in the α-amino group of glutamine. The amount of label recovered in the right cerebral hemisphere, 5 s after a rapid bolus injection of [ 13 N]ammonia via the right common carotid artery, was independent of concentration within the bolus over a 1000-fold range indicating that ammonia enters the brain largely by diffusion. In normal rats approximately 60% of the label recovered in brain was incorporated into glutamine, indicating that the t 1 /sub// 2 for conversion of ammonia to glutamine in the small pool is in the range of 1 to 3 s or less. The data emphasize the importance of the small pool glutamine synthetase as a metabolic trap for the detoxification of blood-borne and endogenously produced brain ammonia. The possibility that the astrocytes represent the anatomical site of the small pool is considered

Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism

Science.gov (United States)

Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Lamers, Wouter H.; Chaudhry, Farrukh A.; Verlander, Jill W.

2016-01-01

Glutamine synthetase (GS) catalyzes the recycling of NH4+ with glutamate to form glutamine. GS is highly expressed in the renal proximal tubule (PT), suggesting ammonia recycling via GS could decrease net ammoniagenesis and thereby limit ammonia available for net acid excretion. The purpose of the present study was to determine the role of PT GS in ammonia metabolism under basal conditions and during metabolic acidosis. We generated mice with PT-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Under basal conditions, PT-GS-KO increased urinary ammonia excretion significantly. Increased ammonia excretion occurred despite decreased expression of key proteins involved in renal ammonia generation. After the induction of metabolic acidosis, the ability to increase ammonia excretion was impaired significantly by PT-GS-KO. The blunted increase in ammonia excretion occurred despite greater expression of multiple components of ammonia generation, including SN1 (Slc38a3), phosphate-dependent glutaminase, phosphoenolpyruvate carboxykinase, and Na+-coupled electrogenic bicarbonate cotransporter. We conclude that 1) GS-mediated ammonia recycling in the PT contributes to both basal and acidosis-stimulated ammonia metabolism and 2) adaptive changes in other proteins involved in ammonia metabolism occur in response to PT-GS-KO and cause an underestimation of the role of PT GS expression. PMID:27009341

Functions of phenylalanine residues within the beta-barrel stem of the anthrax toxin pore.

Directory of Open Access Journals (Sweden)

Jie Wang

2009-07-01

Full Text Available A key step of anthrax toxin action involves the formation of a protein-translocating pore within the endosomal membrane by the Protective Antigen (PA moiety. Formation of this transmembrane pore by PA involves interaction of the seven 2beta2-2beta3 loops of the heptameric precursor to generate a 14-strand transmembrane beta barrel.We examined the effects on pore formation, protein translocation, and cytotoxicity, of mutating two phenylalanines, F313 and F314, that lie at the tip the beta barrel, and a third one, F324, that lies part way up the barrel.Our results show that the function of these phenylalanine residues is to mediate membrane insertion and formation of stable transmembrane channels. Unlike F427, a key luminal residue in the cap of the pore, F313, F314, and F324 do not directly affect protein translocation through the pore. Our findings add to our knowledge of structure-function relationships of a key virulence factor of the anthrax bacillus.

Ammonia Release on ISS

Science.gov (United States)

Macatangay, Ariel

2009-01-01

Crew: Approximately 53% metabolic load Product of protein metabolism Limit production of ammonia by external regulation NOT possbile Payloads Potential source Scientific experiments Thorough safety review ensures sufficient levels of containment

Phenylalanine hydroxylase deficiency caused by a single base substitution in an exon of the human phenylalanine hydroxylase gene

International Nuclear Information System (INIS)

Lichter-Konecki, U.; Konecki, D.S.; DiLella, A.G.; Brayton, K.; Marvit, J.; Hahn, T.M.; Trefz, E.K.; Woo, S.L.C.

1988-01-01

A novel restriction fragment length polymorphism in the phenylalanine hydroxylase (PAH) locus generated by the restriction endonuclease MspI was observed in a German phenylketonuria (PKU) patient. Molecular cloning and DNA sequence analyses revealed that the MspI polymorphism was created by a T to C transition in exon 9 of the human PAH gene, which also resulted in the conversion of a leucine codon to proline codon. The effect of the amino acid substitution was investigated by creating a corresponding mutation in a full-length human PAD cDNA by site-directed mutagenesis followed by expression analysis in cultured mammalian cells. Results demonstrate that the mutation in the gene causes the synthesis of an unstable protein in the cell corresponding to a CRM - phenotype. Together with the other mutations recently reported in the PAH gene,the data support previous biochemical and clinical observations that PKU is a heterogeneous disorder at the gene level

Phenylalanine hydroxylase deficiency caused by a single base substitution in an exon of the human phenylalanine hydroxylase gene

Energy Technology Data Exchange (ETDEWEB)

Lichter-Konecki, U.; Konecki, D.S.; DiLella, A.G.; Brayton, K.; Marvit, J.; Hahn, T.M.; Trefz, E.K.; Woo, S.L.C.

1988-04-19

A novel restriction fragment length polymorphism in the phenylalanine hydroxylase (PAH) locus generated by the restriction endonuclease MspI was observed in a German phenylketonuria (PKU) patient. Molecular cloning and DNA sequence analyses revealed that the MspI polymorphism was created by a T to C transition in exon 9 of the human PAH gene, which also resulted in the conversion of a leucine codon to proline codon. The effect of the amino acid substitution was investigated by creating a corresponding mutation in a full-length human PAD cDNA by site-directed mutagenesis followed by expression analysis in cultured mammalian cells. Results demonstrate that the mutation in the gene causes the synthesis of an unstable protein in the cell corresponding to a CRM/sup -/ phenotype. Together with the other mutations recently reported in the PAH gene,the data support previous biochemical and clinical observations that PKU is a heterogeneous disorder at the gene level.

A study on ammonia removal properties using clinoptilolite Part 1 : characterization of clinoptilolite and ammonia removal properties in batch reactor

Energy Technology Data Exchange (ETDEWEB)

Moon, Jeong Min; Chung, Jong Shik [Dept. of Chemical Engineering/School of Environment Engineering, Pohang University of Science and Technology, Pohang (Korea); Sun, De Shi [Dept. of Applied Chemistry, Harbin Institute of Techonology (China)

2000-04-01

A natural zeolite, deposit located at Guryongpo, Young-il bay, was found to be clinoptilolite containing impurities of heulandite and mordenite. Cation exchange capacity(CEC) for ammonia was about 1.41 meq/g from Na{sup +}-form of the zeolite. In batch experiment, removal efficiency of ammonia was increased as particle size of zeolite and initial concentration of Na{sup +} were decreased and SR(Stoichiometric Ratio), time, and initial concentration of ammonia increased. More than 70% aluminum ion could be removed from water having 3 ppm ammonia and 0.7 ppm Al{sup 3+} by the batch adsorption(ion exchange) experiment. Regeneration of used zeolite with NaCl solution of pH=12 has shown more than 95% of regeneration efficiency when SR'(ratio of the amount of NaCl solution employed actually to the amount in a stoichiometric quantity) was equal to 2.0. 19 refs., 10 figs., 1 tab.

Atmospheric Fate and Transport of Agricultural Dust and Ammonia

Science.gov (United States)

Hiranuma, N.; Brooks, S. D.; Thornton, D. C.; Auvermann, B. W.; Fitz, D. R.

2008-12-01

Agricultural fugitive dust and odor are significant sources of localized air pollution in the semi-arid southern Great Plains. Daily episodes of ground-level fugitive dust emissions from the cattle feedlots associated with increased cattle activity in the early evenings are routinely observed, while consistently high ammonia is observed throughout the day. Here we present measurements of aerosol size distributions and concentrations of gas and particulate phase ammonia species collected at a feedlot in Texas during summers of 2006, 2007 and 2008. A GRIMM sequential mobility particle sizer and GRIMM 1.108 aerosol spectrometer were used to determine aerosol size distributions in the range of 10 nm to 20 µm aerodynamic diameter at the downwind and upwind edges of the facility. Using aqueous scrubbers, simultaneous measurements of both gas phase and total ammonia species present in the gas and particle phases were also collected. In addition to the continuous measurements at the edges of the facility, coincident aerosol and ammonia measurements were obtain at an additional site further downwind (~3.5 km). Taken together our measurements will be used to quantify aerosol and ammonia dispersion and transport. Relationships between the fate and transport of the aerosols and ammonia will be discussed.

Investigations of blood ammonia analysis: Test matrices, storage, and stability.

Science.gov (United States)

Goldstein, Brittany N; Wesler, Jordan; Nowacki, Amy S; Reineks, Edmunds; Natowicz, Marvin R

2017-06-01

An assessment of blood ammonia concentration is common medical practice in the evaluation of an individual with an unexplained mental status change or coma. The determination of a blood ammonia level is most commonly done using a glutamate dehydrogenase (GLDH)-based assay, although there are many potential sources of artifact and the literature is inconsistent regarding key preanalytic issues. Using a GLDH-based assay, we first investigated matrix effects using three anticoagulants: heparin, EDTA and oxalate. Heparin-anticoagulated plasma was substantially less precise than EDTA- and oxalate-anticoagulated plasma. Oxalate-anticoagulated plasma showed a greater baseline of apparent ammonia than either heparin- or EDTA-derived plasma, presumably due to interferants. We then evaluated the stability of EDTA-anticoagulated plasma for assessment of ammonia when stored at 4°C,-14°C or -70°C. There was a linear increase of ammonia with storage at both 4°C and -14°C. Plasma kept at -70°C for up to three weeks showed no change in measured ammonia relative to the baseline determination. This work clarifies preanalytic conditions for which a precise determination of ammonia can be accomplished using a GLDH-based assay. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Photoionization and Recombination

Science.gov (United States)

Nahar, Sultana N.

2000-01-01

Theoretically self-consistent calculations for photoionization and (e + ion) recombination are described. The same eigenfunction expansion for the ion is employed in coupled channel calculations for both processes, thus ensuring consistency between cross sections and rates. The theoretical treatment of (e + ion) recombination subsumes both the non-resonant recombination ("radiative recombination"), and the resonant recombination ("di-electronic recombination") processes in a unified scheme. In addition to the total, unified recombination rates, level-specific recombination rates and photoionization cross sections are obtained for a large number of atomic levels. Both relativistic Breit-Pauli, and non-relativistic LS coupling, calculations are carried out in the close coupling approximation using the R-matrix method. Although the calculations are computationally intensive, they yield nearly all photoionization and recombination parameters needed for astrophysical photoionization models with higher precision than hitherto possible, estimated at about 10-20% from comparison with experimentally available data (including experimentally derived DR rates). Results are electronically available for over 40 atoms and ions. Photoionization and recombination of He-, and Li-like C and Fe are described for X-ray modeling. The unified method yields total and complete (e+ion) recombination rate coefficients, that can not otherwise be obtained theoretically or experimentally.

The production of ammonia by multiheme cytochromes C.

Science.gov (United States)

Simon, Jörg; Kroneck, Peter M H

2014-01-01

The global biogeochemical nitrogen cycle is essential for life on Earth. Many of the underlying biotic reactions are catalyzed by a multitude of prokaryotic and eukaryotic life forms whereas others are exclusively carried out by microorganisms. The last century has seen the rise of a dramatic imbalance in the global nitrogen cycle due to human behavior that was mainly caused by the invention of the Haber-Bosch process. Its main product, ammonia, is a chemically reactive and biotically favorable form of bound nitrogen. The anthropogenic supply of reduced nitrogen to the biosphere in the form of ammonia, for example during environmental fertilization, livestock farming, and industrial processes, is mandatory in feeding an increasing world population. In this chapter, environmental ammonia pollution is linked to the activity of microbial metalloenzymes involved in respiratory energy metabolism and bioenergetics. Ammonia-producing multiheme cytochromes c are discussed as paradigm enzymes.

Plant hormone interaction and phenolic metabolism in the regulation of russet spotting in iceberg lettuce.

Science.gov (United States)

Ke, D; Saltveit, M E

1988-12-01

Russet spotting (RS) is a physiological disorder induced in iceberg lettuce (Lactuca sativa L.) by exposure to parts per million levels of ethylene at 5 +/- 2 degrees C. Ethylene induced phenylalanine ammonia-lyase and ionically bound peroxidase activities that correlated with development of RS symptoms. The ethylene-treated tissue had significantly higher lignin content than air control tissue with lignification localized in walls of RS-affected cells. Ethylene also caused the accumulation of the flavonoids (+)catechin and (-)epicatechin and the chlorogenic acid derivatives 3-caffeoyl-quinic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid. These soluble phenolic compounds were readily oxidized to brown substances by polyphenol oxidase isolated from RS tissue. Ethylene substantially increased ionically bound indole-3-acetic acid (IAA) oxidase activity, while IAA application greatly reduced ethylene-induced phenylalanine ammonia-lyase, peroxidase, and IAA oxidase activities, soluble phenolic content, and RS development.

Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

Science.gov (United States)

Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

2017-12-01

The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

Impact Assessment and Environmental Evaluation of Various Ammonia Production Processes.

Science.gov (United States)

Bicer, Yusuf; Dincer, Ibrahim; Vezina, Greg; Raso, Frank

2017-05-01

In the current study, conventional resources-based ammonia generation routes are comparatively studied through a comprehensive life cycle assessment. The selected ammonia generation options range from mostly used steam methane reforming to partial oxidation of heavy oil. The chosen ammonia synthesis process is the most common commercially available Haber-Bosch process. The essential energy input for the methods are used from various conventional resources such as coal, nuclear, natural gas and heavy oil. Using the life cycle assessment methodology, the environmental impacts of selected methods are identified and quantified from cradle to gate. The life cycle assessment outcomes of the conventional resources based ammonia production routes show that nuclear electrolysis-based ammonia generation method yields the lowest global warming and climate change impacts while the coal-based electrolysis options bring higher environmental problems. The calculated greenhouse gas emission from nuclear-based electrolysis is 0.48 kg CO 2 equivalent while it is 13.6 kg CO 2 per kg of ammonia for coal-based electrolysis method.

Stepwise dehydrogenation of ammonia on Fcc-Co surfaces: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Ma, F.F.; Ma, S.H., E-mail: mash.phy@htu.edu.cn; Jiao, Z.Y.; Dai, X.Q.

2017-05-31

Highlights: • On Co surfaces, oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation on the Co surfaces. • Pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. • The dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces. • The species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom. - Abstract: The stepwise dehydrogenation of ammonia on clean and O-covered Co surfaces have been studied by performing density functional theory (DFT) calculations. It is found that the interaction of species NH{sub x} (x = 0–3) with the Co surfaces become stronger with its further dehydrogenation, and oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation. Specifically, pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. In contrast, the dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces, due to the high energy barriers. And present results demonstrate that the species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom.

Stepwise dehydrogenation of ammonia on Fcc-Co surfaces: A DFT study

International Nuclear Information System (INIS)

Ma, F.F.; Ma, S.H.; Jiao, Z.Y.; Dai, X.Q.

2017-01-01

Highlights: • On Co surfaces, oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation on the Co surfaces. • Pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. • The dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces. • The species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom. - Abstract: The stepwise dehydrogenation of ammonia on clean and O-covered Co surfaces have been studied by performing density functional theory (DFT) calculations. It is found that the interaction of species NH x (x = 0–3) with the Co surfaces become stronger with its further dehydrogenation, and oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation. Specifically, pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. In contrast, the dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces, due to the high energy barriers. And present results demonstrate that the species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom.

Anaerobic ammonia removal in presence of organic matter: A novel route

International Nuclear Information System (INIS)

Sabumon, P.C.

2007-01-01

This study describes the feasibility of anaerobic ammonia removal process in presence of organic matter. Different sources of biomass collected from diverse eco-systems containing ammonia and organic matter (OM) were screened for potential anaerobic ammonia removal. Sequential batch studies confirmed the possibility of anaerobic ammonia removal in presence of OM, but ammonia was oxidized anoxically to nitrate (at oxidation reduction potential; ORP -248 ± 25 mV) by an unknown mechanism unlike in the reported anammox process. The oxygen required for oxidation of ammonia might have been generated through catalase enzymatic activity of facultative anaerobes in mixed culture. The oxygen generation possibility by catalase enzyme route was demonstrated. Among the inorganic electron acceptors (NO 2 - , NO 3 - and SO 4 2- ) studied, NO 2 - was found to be most effective in total nitrogen removal. Denitrification by the developed culture was much effective and faster compared to ammonia oxidation. The results of this study show that anaerobic ammonia removal is feasible in presence of OM. The novel nitrogen removal route is hypothesized as enzymatic anoxic oxidation of NH 4 + to NO 3 - , followed by denitrification via autotrophic and/or heterotrophic routes. The results of batch study were confirmed in continuous reactor operation

Planar optical waveguide sensor of ammonia

Science.gov (United States)

Sarkisov, Sergey S.; Curley, Michael J.; Boykin, Courtney; Diggs, Darnell E.; Grote, James G.; Hopkins, Frank K.

2004-12-01

We describe a novel sensor of ammonia based on a planar optical waveguide made of a thin film of polymer polyimide doped with indicator dye bromocresol purple. The film of dye-doped polyimide demonstrated reversible increase of absorption with a peak near 600 nm in response to presence of ammonia in ambient air. Coupling of input and output optic fibers with the waveguide was done by means of coupling prisms or coupling grooves. The latter configuration has the advantage of low cost, less sensitivity to temperature variation, and the possibility of coupling from both sides of the waveguide. Special experimental setup was built to test the sensor. It included test gas chamber with sealed optic fiber feed-throughs, gas filling line, laser source, photodetector, and signal processing hardware and software. The sensor was capable of detecting 100 ppm of ammonia in air within 8 seconds. Further increase of sensitivity can be achieved by adding more dye dopant to the polymer, increase of the length of the waveguide, and suppression of noise. Overexposure of the sensor to more than 5000 ppm of ammonia led to the saturation of the polymer film and, as a result, significant decrease of sensitivity and increase of the response time. The sensor can be used as low cost component of a distributed optical network of chemical sensors for monitoring presence of hazardous industrial pollutants in air.

On the stability of the disordered molecular alloy phase of ammonia hemihydrate

International Nuclear Information System (INIS)

Wilson, C. W.; Bull, C. L.; Stinton, G. W.; Amos, D. M.; Donnelly, M.-E.; Loveday, J. S.

2015-01-01

The disordered-molecular-alloy phase (DMA) of ammonia hydrates [J. S. Loveday and R. J. Nelmes, Phys. Rev. Lett. 83, 4329 (1999)] is unique in that it has substitutional disorder of ammonia and water over the molecular sites of a body centred cubic lattice. Whilst this structure has been observed in ammonia di- and mono-hydrate compositions, it has not been conclusively observed in the ammonia hemihydrate system. This work presents investigations of the structural behaviour of ammonia hemihydrate as a function of P and T. The indications of earlier studies [Ma et al. RSC Adv. 2, 4290 (2012)] that the DMA structure could be produced by compression of ammonia hemihydrate above 20 GPa at ambient temperature are confirmed. In addition, the DMA structure was found to form reversibly both from the melt, and on warming of ammonia hemihydrate phase-II, in the pressure range between 4 and 8 GPa. The route used to make the DMA structure from ammonia mono- and di-hydrates—compression at 170 K to 6 GPa followed by warming to ambient temperature—was found not to produce the DMA structure for ammonia hemihydrate. These results provide the first strong evidence that DMA is a thermodynamically stable form. A high-pressure phase diagram for ammonia hemihydrate is proposed which has importance for planetary modelling

Lignin solubilisation and gentle fractionation in liquid ammonia

NARCIS (Netherlands)

Strassberger, Z.; Prinsen, P.; Klis, van der F.; Es, van D.S.; Tanase, S.; Rothenberg, G.

2015-01-01

We present a simple method for solubilising lignin using liquid ammonia. Unlike water, which requires harsh conditions, ammonia can solubilise technical lignins, in particular kraft lignin. A commercial pine wood Kraft lignin (Indulin AT) was solubilized instantaneously at room temperature and 7–11

46 CFR 111.105-32 - Bulk liquefied flammable gas and ammonia carriers.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk liquefied flammable gas and ammonia carriers. 111... gas and ammonia carriers. (a) Each vessel that carries bulk liquefied flammable gases or ammonia as a.... (2) The term “gas-dangerous” does not include the weather deck of an ammonia carrier. (c) Each...

ISS Ammonia Leak Detection Through X-Ray Fluorescence

Science.gov (United States)

Camp, Jordan; Barthelmy, Scott; Skinner, Gerry

2013-01-01

Ammonia leaks are a significant concern for the International Space Station (ISS). The ISS has external transport lines that direct liquid ammonia to radiator panels where the ammonia is cooled and then brought back to thermal control units. These transport lines and radiator panels are subject to stress from micrometeorites and temperature variations, and have developed small leaks. The ISS can accommodate these leaks at their present rate, but if the rate increased by a factor of ten, it could potentially deplete the ammonia supply and impact the proper functioning of the ISS thermal control system, causing a serious safety risk. A proposed ISS astrophysics instrument, the Lobster X-Ray Monitor, can be used to detect and localize ISS ammonia leaks. Based on the optical design of the eye of its namesake crustacean, the Lobster detector gives simultaneously large field of view and good position resolution. The leak detection principle is that the nitrogen in the leaking ammonia will be ionized by X-rays from the Sun, and then emit its own characteristic Xray signal. The Lobster instrument, nominally facing zenith for its astrophysics observations, can be periodically pointed towards the ISS radiator panels and some sections of the transport lines to detect and localize the characteristic X-rays from the ammonia leaks. Another possibility is to use the ISS robot arm to grab the Lobster instrument and scan it across the transport lines and radiator panels. In this case the leak detection can be made more sensitive by including a focused 100-microampere electron beam to stimulate X-ray emission from the leaking nitrogen. Laboratory studies have shown that either approach can be used to locate ammonia leaks at the level of 0.1 kg/day, a threshold rate of concern for the ISS. The Lobster instrument uses two main components: (1) a microchannel plate optic (also known as a Lobster optic) that focuses the X-rays and directs them to the focal plane, and (2) a CCD (charge

BLOOD AMMONIA AND GLUTAMINE AS PREDICTORS OF HYPERAMMONEMIC CRISES IN UREA CYCLE DISORDER PATIENTS

Science.gov (United States)

Lee, Brendan; Diaz, George A.; Rhead, William; Lichter-Konecki, U.; Feigenbaum, Annette; Berry, Susan A.; Le Mons, C.; Bartley, James A; Longo, Nicola; Nagamani, Sandesh C.; Berquist, William; Gallagher, Renata; Bartholomew, Dennis; Harding, Cary O.; Korson, Mark S.; McCandless, Shawn E.; Smith, Wendy; Cederbaum, Stephen; Wong, Derek; Merritt, J. Lawrence; Schulze, A.; Vockley, Gerard.; Kronn, David; Zori, Roberto; Summar, Marshall; Milikien, D.A.; Marino, M.; Coakley, D.F.; Mokhtarani, M.; Scharschmidt, B.F.

2014-01-01

Purpose To examine predictors of ammonia exposure and hyperammonemic crises (HAC) in patients with urea cycle disorders (UCDs). Methods The relationships between fasting ammonia, daily ammonia exposure, and HACs were analyzed in >100 UCD patients. Results Fasting ammonia correlated strongly with daily ammonia exposure (r=0.764, p200% (purea nitrogen. Fasting glutamine correlated weakly with AUC0-24 and was not a significant predictor of HACs. Conclusions Fasting ammonia correlates strongly and positively with daily ammonia exposure and with the risk and rate of HACs, suggesting that UCD patients may benefit from tight ammonia control. PMID:25503497

Procedure for the in vitro determination of ammonia in blood

International Nuclear Information System (INIS)

Jung, K.; Faust, H.

1985-01-01

The invention has been aimed at a procedure for the in vitro determination of ammonia in blood based on microdiffusion and isotope dilution analysis. A definite quantity of blood serum has been mixed with a definite quantity of ammonium chloride labelled with the stable isotope 15 N. The mixture has been subjected to the microdiffusion (K 2 CO 3 additives and absorption of released ammonia in sulphuric acid). The ammonia bound in sulphuric acid has been devoted to a isotope analysis and the ammonia concentration of blood has been determined according to the isotope dilution analysis equation

Numerical Study of Ammonia Leak and Dispersion in the International Space Station

Science.gov (United States)

Son, Chang H.

2012-01-01

Release of ammonia into the International Space Station (ISS) cabin atmosphere can occur if the water/ammonia barrier breach of the active thermal control system (ATCS) interface heat exchanger (IFHX) happens. After IFHX breach liquid ammonia is introduced into the water-filled internal thermal control system (ITCS) and then to the cabin environment through a ruptured gas trap. Once the liquid water/ammonia mixture exits ITCS, it instantly vaporizes and mixes with the U.S. Laboratory cabin air that results in rapid deterioration of the cabin conditions. The goal of the study is to assess ammonia propagation in the Station after IFHX breach to plan the operation procedure. A Computational Fluid Dynamics (CFD) model for accurate prediction of airflow and ammonia transport within each of the modules in the ISS cabin was developed. CFD data on ammonia content in the cabin aisle way of the ISS and, in particular, in the Russian On- Orbit Segment during the period of 15 minutes after gas trap rupture are presented for four scenarios of rupture response. Localized effects of ammonia dispersion and risk mitigation are discussed.

Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia.

Science.gov (United States)

Tian, Hailin; Fotidis, Ioannis A; Mancini, Enrico; Angelidaki, Irini

2017-05-01

Bioaugmentation with ammonia tolerant-methanogenic consortia was proposed as a solution to overcome ammonia inhibition during anaerobic digestion process recently. However, appropriate technology to generate ammonia tolerant methanogenic consortia is still lacking. In this study, three basic reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method. Meanwhile, CSTR reactors were inhibited at lower ammonia levels. Finally, specific methanogenic activity test showed that hydrogenotrophic methanogens were more active than aceticlastic methanogens in all FAN levels above 540mgNH 3 -NL -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Anaerobic digestion of swine manure: Inhibition by ammonia

DEFF Research Database (Denmark)

Hansen, Kaare Hvid; Angelidaki, Irini; Ahring, Birgitte Kiær

1998-01-01

A stable anaerobic degradation of swine manure with ammonia concentration of 6 g-N/litre was obtained in continuously stirred tank reactors with a hydraulic retention time of 15 days, at Four different temperatures. Methane yields of 188, 141, 67 and 22 ml-CH4/g-VS were obtained at 37, 45, 55...... and 60 degrees C, respectively. The yields were significantly lower than the potential biogas yield of the swine manure used (300 ml-CH4/g-VS). A free ammonia concentration of 1.1 g-N/litre or more was found to cause inhibition in batch cultures at pH 8.0 (reactor pH), and higher free ammonia...... concentrations resulted in a decreased apparent specific growth rate. Batch experiments with various mixtures of swine and cattle manure showed that the biogas process was inhibited when the swine-to-cattle manure ratio was higher than 25:75, corresponding to a free ammonia concentration of approximately 1.1 g...

Serial ammonia measurement in patients poisoned with glufosinate ammonium herbicide.

Science.gov (United States)

Moon, J M; Chun, B J

2016-05-01

This study investigated whether ammonia concentrations can predict delayed neurotoxicity development and neurotoxicity latency in glufosinate ammonium (GLA) herbicide-poisoned patients presenting with an alert mental state and stable hemodynamics. This retrospective observational case study included 26 patients divided into 2 groups: neurotoxicity during hospitalization (complicated group) and without neurotoxicity (noncomplicated group). Thirteen patients (50.0%) experienced neurotoxicity at 16 h post-ingestion. Although ammonia concentrations at presentation did not differ significantly between the two groups, the ammonia level in the complicated group increased significantly at the next measurement and remained significantly higher than that in the noncomplicated group until 48 h after ingestion. The peak ammonia concentration before neurotoxicity development was an independent predictor of neurotoxicity (odds ratio: 1.047, 95% confidence interval: 1.010-1.087, p value = 0.014), and the optimal cutoff value of peak ammonia concentration for predicting neurotoxicity was 101.5 μg/dL. The rate of ammonia increase was not associated with the time latency from ingestion to neurotoxicity development. This study showed that serial ammonia measurements in GLA-poisoned patients may identify those who are at high risk of developing neurotoxicity. However, as this study enrolled few patients, further qualified trials are required to confirm our results and to reveal the etiology of hyperammonemia and its causality in neurotoxicity. © The Author(s) 2015.

Mathematical Model of Ammonia Handling in the Rat Renal Medulla

Science.gov (United States)

Noiret, Lorette; Baigent, Stephen; Jalan, Rajiv; Thomas, S. Randall

2015-01-01

The kidney is one of the main organs that produces ammonia and release it into the circulation. Under normal conditions, between 30 and 50% of the ammonia produced in the kidney is excreted in the urine, the rest being absorbed into the systemic circulation via the renal vein. In acidosis and in some pathological conditions, the proportion of urinary excretion can increase to 70% of the ammonia produced in the kidney. Mechanisms regulating the balance between urinary excretion and renal vein release are not fully understood. We developed a mathematical model that reflects current thinking about renal ammonia handling in order to investigate the role of each tubular segment and identify some of the components which might control this balance. The model treats the movements of water, sodium chloride, urea, NH3 and NH4+, and non-reabsorbable solute in an idealized renal medulla of the rat at steady state. A parameter study was performed to identify the transport parameters and microenvironmental conditions that most affect the rate of urinary ammonia excretion. Our results suggest that urinary ammonia excretion is mainly determined by those parameters that affect ammonia recycling in the loops of Henle. In particular, our results suggest a critical role for interstitial pH in the outer medulla and for luminal pH along the inner medullary collecting ducts. PMID:26280830

Effects of gaseous ammonia direct injection on performance characteristics of a spark-ignition engine

International Nuclear Information System (INIS)

Ryu, Kyunghyun; Zacharakis-Jutz, George E.; Kong, Song-Charng

2014-01-01

Highlights: • This is the very first study in utilizing direct injection of gaseous ammonia in an SI engine. • Engine combustion using direct injection of gaseous ammonia is proven feasible. • Energy efficiency using ammonia is comparable to that using gasoline. • CO emissions are decreased but emissions of NOx and HC are increased when ammonia is used. - Abstract: The effects of direct injection of gaseous ammonia on the combustion characteristics and exhaust emissions of a spark-ignition engine were investigated. Port-injection gasoline was used to enhance the burning of ammonia that was directly injected into the engine cylinder. Appropriate direct injection strategies were developed to allow ammonia to be used in spark-ignition engines without sacrifice of volumetric efficiency. Experimental results show that with gasoline providing the baseline power of 0.6 kW, total engine power could increase to 2.7 kW when the injection timing of ammonia was advanced to 370 BTDC with injection duration of 22 ms. Engine performance with use of gasoline–ammonia was compared to that with gasoline alone. For operations using gasoline–ammonia, with baseline power from gasoline at 0.6 kW the appropriate ammonia injection timing was found to range from 320 to 370 BTDC for producing 1.5–2.7 kW. The peak pressures were slightly lower than those using gasoline alone because of the lower flame of ammonia, resulting in reduction of cylinder pressure. The brake specific energy consumption (BSEC) with gasoline–ammonia was very similar to that with gasoline alone. Ammonia direct injection caused slight reductions of BSCO for all the loads studied but significantly increased BSHC because of the reduced combustion temperature of ammonia combustion. The use of ammonia resulted in increased NOx emissions because of formation of fuel NOx. Ammonia slip was also detected in the engine exhaust because of incomplete combustion

Dynamic Model of an Ammonia Synthesis Reactor Based on Open Information

OpenAIRE

Jinasena, Asanthi; Lie, Bernt; Glemmestad, Bjørn

2016-01-01

Ammonia is a widely used chemical, hence the ammonia manufacturing process has become a standard case study in the scientific community. In the field of mathematical modeling of the dynamics of ammonia synthesis reactors, there is a lack of complete and well documented models. Therefore, the main aim of this work is to develop a complete and well documented mathematical model for observing the dynamic behavior of an industrial ammonia synthesis reactor system. The model is complete enough to ...

Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant

International Nuclear Information System (INIS)

Cinti, Giovanni; Frattini, Domenico; Jannelli, Elio; Desideri, Umberto; Bidini, Gianni

2017-01-01

Highlights: • An innovative NH 3 production plant was designed. • CO 2 emissions and energy consumption are studied in three different designs. • High temperature electrolysis allows to achieve high efficiency and heat recovery. • The coupling permits storage of electricity into a liquid carbon free chemical. - Abstract: Ammonia is one of the most produced chemicals worldwide and is currently synthesized using nitrogen separated from air and hydrogen from natural gas reforming with consequent high consumption of fossil fuel and high emission of CO 2 . A renewable path for ammonia production is desirable considering the potential development of ammonia as energy carrier. This study reports design and analysis of an innovative system for the production of green ammonia using electricity from renewable energy sources. This concept couples Solid Oxide Electrolysis (SOE), for the production of hydrogen, with an improved Haber Bosch Reactor (HBR), for ammonia synthesis. An air separator is also introduced to supply pure nitrogen. SOE operates with extremely high efficiency recovering high temperature heat from the Haber-Bosch reactor. Aspen was used to develop a model to study the performance of the plant. Both the SOE and the HBR operate at 650 °C. Ammonia production with zero emission of CO 2 can be obtained with a reduction of 40% of power input compared to equivalent plants.

Ammonia lowering reverses sarcopenia of cirrhosis by restoring skeletal muscle proteostasis.

Science.gov (United States)

Kumar, Avinash; Davuluri, Gangarao; Silva, Rafaella Nascimento E; Engelen, Marielle P K J; Ten Have, Gabrie A M; Prayson, Richard; Deutz, Nicolaas E P; Dasarathy, Srinivasan

2017-06-01

Sarcopenia or skeletal muscle loss is a frequent, potentially reversible complication in cirrhosis that adversely affects clinical outcomes. Hyperammonemia is a consistent abnormality in cirrhosis that results in impaired skeletal muscle protein synthesis and breakdown (proteostasis). Despite the availability of effective ammonia-lowering therapies, whether lowering ammonia restores proteostasis and increases muscle mass is unknown. Myotube diameter, protein synthesis, and molecular responses in C2C12 murine myotubes to withdrawal of ammonium acetate following 24-hour exposure to 10 mM ammonium acetate were complemented by in vivo studies in the hyperammonemic portacaval anastomosis rat and sham-operated, pair-fed Sprague-Dawley rats treated with ammonia-lowering therapy by l-ornithine l-aspartate and rifaximin orally for 4 weeks. We observed reduced myotube diameter, impaired protein synthesis, and increased autophagy flux in response to hyperammonemia, which were partially reversed following 24-hour and 48-hour withdrawal of ammonium acetate. Consistently, 4 weeks of ammonia-lowering therapy resulted in significant lowering of blood and skeletal muscle ammonia, increase in lean body mass, improved grip strength, higher skeletal muscle mass and diameter, and an increase in type 2 fibers in treated compared to untreated portacaval anastomosis rats. The increased skeletal muscle myostatin expression, reduced mammalian target of rapamycin complex 1 function, and hyperammonemic stress response including autophagy markers normally found in portacaval anastomosis rats were reversed by treatment with ammonia-lowering therapy. Despite significant improvement, molecular and functional readouts were not completely reversed by ammonia-lowering measures. Ammonia-lowering therapy results in improvement in skeletal muscle phenotype and function and molecular perturbations of hyperammonemia; these preclinical studies complement previous studies on ammonia-induced skeletal muscle

Orion Ammonia Boiler System Preflight Test Preparations

Science.gov (United States)

Levitt, Julia L.

2017-01-01

The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

On-board ammonia generation and exhaust after treatment system using same

Science.gov (United States)

Driscoll, Josh; Robel, Wade J.; Brown, Cory A.; Urven, Jr., Roger L.

2010-03-30

Often NOx selective catalysts that use ammonia to reduce NOx within exhaust to a harmless gas require on-board storage of ammonia which can be hazardous and inconvenient. In order to generate ammonia in exhaust, the present disclosure increases a NOx concentration in exhaust from at least one combustion chamber, at least in part, by injecting fuel in a predetermined increased NOx generation sequence that includes a first injection during non-auto ignition conditions and a second injection during auto ignition conditions. At least a portion of the NOx is converted to ammonia by passing at least a portion of the exhaust with the increased NOx concentration over an ammonia-producing catalyst.

Power cycles with ammonia-water mixtures as working fluid

Energy Technology Data Exchange (ETDEWEB)

Thorin, Eva

2000-05-01

It is of great interest to improve the efficiency of power generating processes, i.e. to convert more of the energy in the heat source to power. This is favorable from an environmental point of view and can also be an economic advantage. To use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of steam turbine processes. This thesis includes studies of power cycles with ammonia-water mixtures as working fluid utilizing different kinds of heat sources for power and heat generation. The thermophysical properties of the mixture are also studied. They play an important role in the calculations of the process performance and for the design of its components, such as heat exchangers. The studies concern thermodynamic simulations of processes in applications suitable for Swedish conditions. Available correlations for the thermophysical properties are compared and their influence on simulations and heat exchanger area predictions is investigated. Measurements of ammonia-water mixture viscosities using a vibrating wire viscometer are also described. The studies performed show that power cycles with ammonia-water mixtures as the working fluid are well suited for utilization of waste heat from industry and from gas engines. The ammonia-water power cycles can give up to 32 % more power in the industrial waste heat application and up to 54 % more power in the gas engine bottoming cycle application compared to a conventional Rankine steam cycle. However, ammonia-water power cycles in small direct-fired biomass-fueled cogeneration plants do not show better performance than a conventional Rankine steam cycle. When different correlations for the thermodynamic properties are used in simulations of a simple ammonia-water power cycle the difference in efficiency is not larger than 4 %, corresponding to about 1.3 percentage points. The differences in saturation properties between the correlations are, however, considerable at high

Effect of ammonia on the anaerobic hydrolysis of cellulose and tributyrin

NARCIS (Netherlands)

Vasconcelos Fernandes, T.; Keesman, K.J.; Zeeman, G.; Lier, van J.B.

2012-01-01

Ammonia nitrogen is one of the most common inhibitors in the anaerobic digestion of complex wastes containing high concentrations of ammonia like animal manures, blackwater and waste oil from gastronomy. The inhibiting effect of ammonia on methanogenesis has been well established. In contrast, the

Abatement of ammonia emissions from digested manure using gas-permeable membranes

Science.gov (United States)

A new strategy to avoid ammonia emissions from anaerobically digested swine manure was tested using the gas-permeable membrane process. Evaluation of the efficiency of ammonia recovery from digestate as well as mitigation of ammonia emissions to the atmosphere were carried out. Digestate was colle...

The Full-Scale Implementation of an Innovative Biological Ammonia Treatment Process

Science.gov (United States)

Across the United States, high levels of ammonia in drinking water sources can be found, including small communities like Palo, Iowa (approximate population of 1,026). Although ammonia in water does not pose a direct health concern, ammonia nitrification can cause a number of iss...

Influence of sample quality on phenylalanine and 17-hydroxyprogesterone levels in neonatal screening

OpenAIRE

del Río Fabre, Lesley; González, Ernesto C; Frómeta, Amarilys; Castells, Elisa M; Tejeda, Yileidis

2010-01-01

Quality of the sample and phenylalanine and 17-hydroxyprogesterone levels in neonatal screening. In the programs for neonatal screening many different analytes are quantified from dried blood on filter paper cards. Several factors affect the quality of the samples invalidating their employment in the laboratory: inadequate collection procedures, quality of the filter paper, the drying, storage and transportation under extreme environmental conditions. This article aims to show how the quality...

Decreased STAT3 Phosphorylation Mediates Cell Swelling in Ammonia-Treated Astrocyte Cultures

Directory of Open Access Journals (Sweden)

Arumugam R. Jayakumar

2016-12-01

Full Text Available Brain edema, due largely to astrocyte swelling, and the subsequent increase in intracranial pressure and brain herniation, are major complications of acute liver failure (ALF. Elevated level of brain ammonia has been strongly implicated in the development of astrocyte swelling associated with ALF. The means by which ammonia brings about astrocyte swelling, however, is incompletely understood. Recently, oxidative/nitrosative stress and associated signaling events, including activation of mitogen-activated protein kinases (MAPKs, as well as activation of the transcription factor, nuclear factor-kappaB (NF-κB, have been implicated in the mechanism of ammonia-induced astrocyte swelling. Since these signaling events are known to be regulated by the transcription factor, signal transducer and activator of transcription 3 (STAT3, we examined the state of STAT3 activation in ammonia-treated cultured astrocytes, and determined whether altered STAT3 activation and/or protein expression contribute to the ammonia-induced astrocyte swelling. STAT3 was found to be dephosphorylated (inactivated at Tyrosine705 in ammonia-treated cultured astrocytes. Total STAT3 protein level was also reduced in ammonia-treated astrocytes. We also found a significant increase in protein tyrosine phosphatase receptor type-1 (PTPRT-1 protein expression in ammonia-treated cultured astrocytes, and that inhibition of PTPRT-1 enhanced the phosphorylation of STAT3 after ammonia treatment. Additionally, exposure of cultured astrocytes to inhibitors of protein tyrosine phosphatases diminished the ammonia-induced cell swelling, while cultured astrocytes over-expressing STAT3 showed a reduction in the astrocyte swelling induced by ammonia. Collectively, these studies strongly suggest that inactivation of STAT3 represents a critical event in the mechanism of the astrocyte swelling associated with acute liver failure.

Ammonia Levels and Hepatic Encephalopathy in Patients with Known Chronic Liver Disease.

Science.gov (United States)

Ninan, Jacob; Feldman, Leonard

2017-08-01

Ammonia is predominantly generated in the gut by intestinal bacteria and enzymes and detoxified primarily in the liver. Since the 1930s, ammonia has been identified as the principal culprit in hepatic encephalopathy (HE). Many physicians utilize serum ammonia to diagnose, assess severity, and determine the resolution of HE in patients with chronic liver disease (CLD) despite research showing that ammonia levels are unhelpful in all of these clinical circumstances. HE in patients with CLD is a clinical diagnosis of exclusion that should not be based on ammonia levels. © 2017 Society of Hospital Medicine.

Visible bands of ammonia: band strengths, curves of growth, and the spatial distribution of ammonia on Jupiter

International Nuclear Information System (INIS)

Lutz, B.L.; Owen, T.

1980-01-01

We report room-temperature laboratory studies of the 5520 A (6ν 1 ) and 6475 A (5ν 1 ) bands of self-broadened ammonia at column densities ranging from 1.7--435.7 meter-amagats (m-am). Detailed equivalent-width measurements at 24 different pressure-pathlength combinations corresponding to four pressures between 44 and 689 torr and pathlengths between 32 and 512 m are used to determin curves of growth and integrated band strengths. The band strengths for the 6ν 1 and 5ν 1 overtones are 5520 A: S=0.096 +- 0.005 cm -1 (m-am) -1 and 6475 A: S=0.63 +- 0.03 cm -1 (m-am) -1 , respectively.Using these band strengths and curves of growth, we analyze new spatially resolved spectra of Jupiter showing a nonhomogeneous distribution of ammonia in the Jovian atmosphere. The observed variations in the CH 4 /NH 3 mixing ratio are interpreted as evidence of altitude-dependent depletion of ammonia in the atmosphere

Ammonia-water exchange front end process for ammonia-hydrogen heavy water plants (Preprint No. PD-1)

International Nuclear Information System (INIS)

Sadhukhan, H.K.; Varadarajan, T.G.; Nair, N.K.; Das, S.K.; Nath, G.K.

1989-04-01

The ammonia-hydrogen exchange process, which utilizes the deutrium exchange between liquid ammonia and gaseous hydrogen is a parasitic process and the heavy water plants (HWP) based on this process has to be linked with the fertilizer plant (FP) for its enormous requirements of hydrogen (synthesis gas, N 2 +3H 2 ). This dependence of HWP on FP gives rise to certain constraints which are listed. These deficiencies of the ammonia-hydrogen process can be overcome to a great extent by delinking the HWP from FP by incorporating NH 3 -H 2 O exchange as the front end step. In addition to the elimination of the above limitations, by employing water as the ultimate feed for the HWP, the plant capacity can be increased substantially and this would go a long way in achieving economies of the large capacity plants. A schematic diagram of this integrated plant is given. Some of the results of developmental efforts and feasibility studies of this NH 3 -H 2 O exchange are briefly reviewed. (author). 4 figs

Enrichment of high ammonia tolerant methanogenic culture

DEFF Research Database (Denmark)

Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas

Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas...... was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine...... exclusively to strict aceticlastic methanogens. Results obtained in this study, demonstrated for the first time that strictly aceticlastic methanogens, derived from an enriched culture, can efficiently produce methane under high ammonia levels....

Phase 2 comparison of a novel ammonia scavenging agent with sodium phenylbutyrate in patients with urea cycle disorders: safety, pharmacokinetics and ammonia control.

Science.gov (United States)

Lee, Brendan; Rhead, William; Diaz, George A; Scharschmidt, Bruce F; Mian, Asad; Shchelochkov, Oleg; Marier, J F; Beliveau, Martin; Mauney, Joseph; Dickinson, Klara; Martinez, Antonia; Gargosky, Sharron; Mokhtarani, Masoud; Berry, Susan A

2010-07-01

Glycerol phenylbutyrate (glyceryl tri (4-phenylbutyrate)) (GPB) is being studied as an alternative to sodium phenylbutyrate (NaPBA) for the treatment of urea cycle disorders (UCDs). This phase 2 study explored the hypothesis that GPB offers similar safety and ammonia control as NaPBA, which is currently approved as adjunctive therapy in the chronic management of UCDs, and examined correlates of 24-h blood ammonia. An open-label, fixed sequence switch-over study was conducted in adult UCD patients taking maintenance NaPBA. Blood ammonia and blood and urine metabolites were compared after 7 days (steady state) of TID dosing on either drug, both dosed to deliver the same amount of phenylbutyric acid (PBA). Ten subjects completed the study. Adverse events were comparable for the two drugs; 2 subjects experienced hyperammonemic events on NaPBA while none occurred on GPB. Ammonia values on GPB were approximately 30% lower than on NaPBA (time-normalized AUC=26.2 vs. 38.4 micromol/L; Cmax=56.3 vs. 79.1 micromol/L; not statistically significant), and GPB achieved non-inferiority to NaPBA with respect to ammonia (time-normalized AUC) by post hoc analysis. Systemic exposure (AUC(0-24)) to PBA on GPB was 27% lower than on NaPBA (540 vs. 739 microgh/mL), whereas exposure to phenylacetic acid (PAA) (575 vs. 596 microg h/mL) and phenylacetylglutamine (PAGN) (1098 vs. 1133 microg h/mL) were similar. Urinary PAGN excretion accounted for approximately 54% of PBA administered for both NaPBA and GPB; other metabolites accounted for <1%. Intact GPB was generally undetectable in blood and urine. Blood ammonia correlated strongly and inversely with urinary PAGN (r=-0.82; p<0.0001) but weakly or not at all with blood metabolite levels. Safety and ammonia control with GPB appear at least equal to NaPBA. Urinary PAGN, which is stoichiometrically related to nitrogen scavenging, may be a useful biomarker for both dose selection and adjustment for optimal control of venous ammonia. Copyright

Ammonia loss, ammonium and nitrate accumulation from mixing ...

African Journals Online (AJOL)

Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect of mixing urea with ...

Design, synthesis and structure-activity relationships of novel phenylalanine-based amino acids as kainate receptors ligands

DEFF Research Database (Denmark)

Szymańska, Ewa; Chałupnik, Paulina; Szczepańska, Katarzyna

2016-01-01

A new series of carboxyaryl-substituted phenylalanines was designed, synthesized and pharmacologically characterized in vitro at native rat ionotropic glutamate receptors as well as at cloned homomeric kainate receptors GluK1-GluK3. Among them, six compounds bound to GluK1 receptor subtypes with ...

Fiber Optic Detection of Ammonia Gas

Directory of Open Access Journals (Sweden)

L. Kalvoda

2006-01-01

Full Text Available Bathochromic shifts accompanying the formation of several bivalent metallic complexes containing 5-(4’-dimethylaminophenylimino quinolin-8-one (L1, and 7-chlore-5(4’-diethylamino-2-methylphenylimino quinolin-8-one (L2 ligands in ethanol solutions were evaluated by VIS-NIR spectroscopy. The [L1-Cu-L1] sulphide complex was selected as a reagent for further tests on optical fibres. Samples of multimode siloxane-clad fused-silica fibre were sensitized by diffusing an ethanol/chloroform solution of the dye into the cladding polymer, and tested by VIS-NIR optical spectroscopy (12 cm long fibre sections, and optical time domain reflectometry (OTDR; 20 ns laser pulses, wavelength 850 nm, 120 m long fibre sensitized within the interval 104–110 m. A well-resolved absorption band of the reagent could be identified in the absorption spectra of the fibres. After exposure to dry ammonia/nitrogen gas with increasing ammonia concentration (0–4000 ppm, the short fibre samples showed subsequent decay of NIR optical absorption; saturation was observed for higher ammonia levels. The concentration resolution r ? 50 ppm and forward response time t90 ? 30 sec were obtained within the interval 0–1000 ppm. The OTDR courses showed an enhancement of the back-scattered light intensity coming from the sensitized region after diffusion of the initial reagent, and decay after exposure to concentrated ammonia/nitrogen gas (10000 ppm.

Stabilization of ammonia-rich hydrate inside icy planets.

Science.gov (United States)

Naden Robinson, Victor; Wang, Yanchao; Ma, Yanming; Hermann, Andreas

2017-08-22

The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets-as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H 2 O)(NH 3 ) 2 , is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O 2- ([Formula: see text]) 2 , where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia-water mixture. This suggests it precipitates out of any ammonia-water mixture at sufficiently high pressures and thus forms an important component of icy planets.

Exhaust purification with on-board ammonia production

Science.gov (United States)

Robel, Wade J [Peoria, IL; Driscoll, James Joshua [Dunlap, IL; Coleman, Gerald N [Peterborough, GB

2008-05-13

A system of ammonia production for a selective catalytic reduction system is provided. The system includes producing an exhaust gas stream within a cylinder group, wherein the first exhaust gas stream includes NOx. The exhaust gas stream may be supplied to an exhaust passage and cooled to a predetermined temperature range, and at least a portion of the NOx within the exhaust gas stream may be converted into ammonia.

Arterial ammonia levels in the management of fulminant liver failure

Directory of Open Access Journals (Sweden)

Curry S

2011-06-01

Full Text Available Previous studies have suggested that an arterial ammonia level greater than 150 mmol/L is highly sensitive for predicting subsequent development of cerebral edema in patients with fulminant liver failure. We performed a prospective cohort study to confirm this relationship. We enrolled 22 consecutive patients who presented to our transplant hepatology service with grade 3-4 encephalopathy associated with fulminant liver failure. All patients underwent placement of an intraparenchymal ICP monitor, and every 12 hourly arterial ammonia levels. The prevalence of intracranial hypertension (IHTN in our population was 95% (21/22 patients, with 82 discrete episodes recorded. The sensitivity of arterial ammonia levels to predict the onset of IHTN was 62% (95% CI: 40.8 to 79.3 at a cut point of 150 mmol/L. Arterial ammonia levels preceding the first intracranial hypertension event were less than 150 mmol/L in 8 of 21 patients (39%. Fifty nine of 82 episodes of IHTN (73% occurred when arterial ammonia levels were less than 150 mmol/L. We conclude that the arterial ammonia level is not useful in making decisions regarding management related to cerebral edema in patients with fulminant liver failure. In fact, since almost all our study patients with grade III or IV encephalopathy secondary to fulminant liver failure went on to develop intracranial hypertension, our study supports the contention that all such patients might benefit from ICP monitoring regardless of arterial ammonia levels.

Carbon-dependent alleviation of ammonia toxicity for algae cultivation and associated mechanisms exploration.

Science.gov (United States)

Lu, Qian; Chen, Paul; Addy, Min; Zhang, Renchuan; Deng, Xiangyuan; Ma, Yiwei; Cheng, Yanling; Hussain, Fida; Chen, Chi; Liu, Yuhuan; Ruan, Roger

2018-02-01

Ammonia toxicity in wastewater is one of the factors that limit the application of algae technology in wastewater treatment. This work explored the correlation between carbon sources and ammonia assimilation and applied a glucose-assisted nitrogen starvation method to alleviate ammonia toxicity. In this study, ammonia toxicity to Chlorella sp. was observed when NH 3 -N concentration reached 28.03mM in artificial wastewater. Addition of alpha-ketoglutarate in wastewater promoted ammonia assimilation, but low utilization efficiency and high cost of alpha-ketoglutarate limits its application in wastewater treatment. Comparison of three common carbon sources, glucose, citric acid, and sodium bicarbonate, indicates that in terms of ammonia assimilation, glucose is the best carbon source. Experimental results suggest that organic carbon with good ability of generating energy and hydride donor may be critical to ammonia assimilation. Nitrogen starvation treatment assisted by glucose increased ammonia removal efficiencies and algal viabilities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ammonia nitrogen removal from aqueous solution by local agricultural wastes

Science.gov (United States)

Azreen, I.; Lija, Y.; Zahrim, A. Y.

2017-06-01

Excess ammonia nitrogen in the waterways causes serious distortion to environment such as eutrophication and toxicity to aquatic organisms. Ammonia nitrogen removal from synthetic solution was investigated by using 40 local agricultural wastes as potential low cost adsorbent. Some of the adsorbent were able to remove ammonia nitrogen with adsorption capacity ranging from 0.58 mg/g to 3.58 mg/g. The highest adsorption capacity was recorded by Langsat peels with 3.58 mg/g followed by Jackfruit seeds and Moringa peels with 3.37 mg/g and 2.64 mg/g respectively. This experimental results show that the agricultural wastes can be utilized as biosorbent for ammonia nitrogen removal. The effect of initial ammonia nitrogen concentration, pH and stirring rate on the adsorption process were studied in batch experiment. The adsorption capacity reached maximum value at pH 7 with initial concentration of 500 mg/L and the removal rate decreased as stirring rate was applied.

Predicting catalysis: Understanding ammonia synthesis from first-principles calculations

DEFF Research Database (Denmark)

Hellmann, A.; Baerends, E.J.; Biczysko, M.

2006-01-01

. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully......Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state...... for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations...

Process for producing 13N-ammonia and device therefor

International Nuclear Information System (INIS)

Tanaka, Akira; Suzuki, Hirofumi.

1997-01-01

Ethanol or hydrogen is added to purified water or distilled water for injection, they are filled into a target vessel, and proton beams are irradiated to produce 13N-ammonia in the target vessel. A target liquid containing the resultant is introduced to a heat-reaction vessel. A slight amount of weak alkali solution is added to the target liquid in the heat-reaction vessel. The reaction vessel is heated to evaporate water and 13N-ammonia, and they are transferred to a vial. In this case, nitrogen gas as a gas to be entrained is supplied. 13N-ammonia is subjected to bubbling into the distilled water for injection or physiological saline water and recovered into the vial. 13N-ammonia is thus separated and purified as an injection which is a medical labelled compound. (I.N.)

Ammonia abundances in four comets

International Nuclear Information System (INIS)

Wickoff, S.; Tegler, S.C.; Engel, L.

1991-01-01

NH2 emission band strengths were measured in four comets and the NH2 column densities were determined in order to measure the ammonia content of the comets. The mean ammonia/water abundance ratio derived for the four comets is found to be 0.13 + or - 0.06 percent, with no significant variation among the comets. The uniformity of this abundance attests to a remarkable degree of chemical homogeneity over large scales in the comet-forming region of the primordial solar nebula, and contrasts with the CO abundance variations found previously in comets. The N2 and NH3 abundances indicate a condensation temperature in the range 20-160 K, consistent with virtually all comet formation hypotheses. 64 refs

Reactor for removing ammonia

Science.gov (United States)

Luo, Weifang [Livermore, CA; Stewart, Kenneth D [Valley Springs, CA

2009-11-17

Disclosed is a device for removing trace amounts of ammonia from a stream of gas, particularly hydrogen gas, prepared by a reformation apparatus. The apparatus is used to prevent PEM "poisoning" in a fuel cell receiving the incoming hydrogen stream.

Biotreatment of ammonia and butanal containing waste gases

NARCIS (Netherlands)

Weckhuysen, B.M.; Vriens, L.; Verachtert, H.

1994-01-01

Abstract The biological removal of ammonia and butanal in contaminated air was investigated by using, respectively, a laboratory-scale filter and a scrubber-filter combination. It was shown that ammonia can be removed with an elimination efficiency of 83% at a volumetric load of 100 m3·m–2·h–1 with

Recombiner

International Nuclear Information System (INIS)

Osumi, Morimichi.

1979-01-01

Purpose: To provide a recombiner which is capable of converting hydrogen gas into water by use of high-frequency heating at comparatively low temperatures and is safe and cheap in cost. Constitution: Hydrogen gas is introduced from an outer pipeline to the main structure of a recombiner, and when it passes through the vicinity of the central part of the recombiner, it is reacted with copper oxide (CuO 2 ) heated to a temperature more than 300 0 C by a high-frequency heater, and converted gently into water by reduction operation (2H 2 + CuO 2 → Cu + 2H 2 O). The thus prepared water is exhausted through the outer pipeline to a suppression pool. A part of hydrogen gas which has not been converted completely into water by the reaction and is remaining as hydrogen is recovered through exhaust nozzles and again introduced into the main structure of the recombiner. (Yoshino, Y.)

Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion

Science.gov (United States)

Mitch, William E.; Sands, Jeff M.

2015-01-01

Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. PMID:25078422

Frozen ammonia micropellet generator for Baseball II-T

International Nuclear Information System (INIS)

Denhoy, B.S.

1975-01-01

A ''startup'' plasma at the center of the Baseball II-T magnet was studied. This startup plasma will be used as a target for high energy neutral beams to achieve the required build-up. The target plasma will be created by irradiating a solid pellet with a laser beam. Although a deuterium pellet would be superior because of purity, the development of an ammonia pellet was undertaken because it requires a simpler technology. The ammonia target plasma is physically acceptable for the initial experiment. A frozen ammonia pellet, about 100 μm in diameter, will be irradiated with 300-J CO 2 laser, to produce a density of about 10 13 cm -3 and about 1 kV temperature

Biochemical changes involved in browning of gamma-irradiated cut witloof chicory

International Nuclear Information System (INIS)

Hanotel, L.; Fleuriet, A.; Boisseau, P.

1995-01-01

The increasing browning phenomenon of cut witloof chicory (Cichorium intybus) irradiated with a dose of 3 kGy and stored five days at 10 °C was investigated in relation to total phenolic concentration, phenylalanine ammonia-lyase activity, total and reduced glutathione content, polyphenol oxidase and peroxidase activities. Phenylalanine ammonia-lyase activity underwent a strong activation with a maximum on the second day of storage, and total phenolic compounds tended to accumulate from the third day. Glutathione content was monitored as indicator of antioxidant capacities. Total glutathione decreased by 25% after irradiation and was restored on the third day of storage, while the 50% decrease of reduced glutathione was maintained along the five days. Conversely, a 30% inhibition of polyphenol oxidase and peroxidase activities occured after irradiation. We concluded first that irradiation-induced browning of cut chicory may be due to both an increase of phenolic metabolism and a reduction in antioxidant capacities, and second that increased membrane permeability may allow substrate-enzyme contact

Splicing of phenylalanine hydroxylase (PAH) exon 11 is vulnerable - Molecular pathology of mutations in PAH exon 11

DEFF Research Database (Denmark)

Heintz, Caroline; Dobrowolski, Steven F.; Andersen, Henriette Skovgaard

2012-01-01

as a vulnerable exon and used patient derived lymphoblast cell lines and PAH minigenes to study the molecular defect that impacted pre-mRNA processing. We showed that the c.1144T>C and c.1066-3C>T mutations cause exon 11 skipping, while the c.1139C>T mutation is neutral or slightly beneficial. The c.1144T......In about 20-30% of phenylketonuria (PKU) patients, phenylalanine (Phe) levels can be controlled by cofactor 6R-tetrahydrobiopterin (BH(4)) administration. The phenylalanine hydroxylase (PAH) genotype has a predictive value concerning BH(4)-response and therefore a correct assessment of the mutation...... molecular pathology is important. Mutations that disturb the splicing of exons (e.g. interplay between splice site strength and regulatory sequences like exon splicing enhancers (ESEs)/exon splicing silencers (ESSs)) may cause different severity of PKU. In this study, we identified PAH exon 11...

Acute phenylalanine/tyrosine depletion of phasic dopamine in the rat brain.

Science.gov (United States)

Shnitko, Tatiana A; Taylor, Sarah C; Stringfield, Sierra J; Zandy, Shannon L; Cofresí, Roberto U; Doherty, James M; Lynch, William B; Boettiger, Charlotte A; Gonzales, Rueben A; Robinson, Donita L

2016-06-01

Dopamine plays a critical role in striatal and cortical function, and depletion of the dopamine precursors phenylalanine and tyrosine is used in humans to temporarily reduce dopamine and probe the role of dopamine in behavior. This method has been shown to alter addiction-related behaviors and cognitive functioning presumably by reducing dopamine transmission, but it is unclear what specific aspects of dopamine transmission are altered. We performed this study to confirm that administration of an amino acid mixture omitting phenylalanine and tyrosine (Phe/Tyr[-]) reduces tyrosine tissue content in the prefrontal cortex (PFC) and nucleus accumbens (NAc), and to test the hypothesis that Phe/Tyr[-] administration reduces phasic dopamine release in the NAc. Rats were injected with a Phe/Tyr[-] amino acid mixture, a control amino acid mixture, or saline. High-performance liquid chromatography was used to determine the concentration of tyrosine, dopamine, or norepinephrine in tissue punches from the PFC and ventral striatum. In a separate group of rats, phasic dopamine release was measured with fast-scan cyclic voltammetry in the NAc core after injection with either the Phe/Tyr[-] mixture or the control amino acid solution. Phe/Tyr[-] reduced tyrosine content in the PFC and NAc, but dopamine and norepinephrine tissue content were not reduced. Moreover, Phe/Tyr[-] decreased the frequency of dopamine transients, but not their amplitude, in freely moving rats. These results indicate that depletion of tyrosine via Phe/Tyr[-] decreases phasic dopamine transmission, providing insight into the mechanism by which this method modifies dopamine-dependent behaviors in human imaging studies.

AMMONIA IN THE EARLY SOLAR SYSTEM: AN ACCOUNT FROM CARBONACEOUS METEORITES

International Nuclear Information System (INIS)

Pizzarello, S.; Williams, L. B.

2012-01-01

This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300°C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 μg mg –1 for the Orgueil IOM to 0.5 μg mg –1 for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 μg mg –1 . While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the δ 15 N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original 15 N distribution of pre- and proto-solar materials.

Ammonia in the Early Solar System: An Account from Carbonaceous Meteorites

Science.gov (United States)

Pizzarello, S.; Williams, L. B.

2012-04-01

This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300°C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 μg mg-1 for the Orgueil IOM to 0.5 μg mg-1 for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 μg mg-1. While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the δ15N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original 15N distribution of pre- and proto-solar materials.

Procedures for the synthesis of ethylenediamine bisborane and ammonia borane

Science.gov (United States)

Ramachandran, Padi Veeraraghavan; Gagare, Pravin D.; Mistry, Hitesh; Biswas, Bidyut

2017-01-03

A method for synthesizing ammonia borane includes (a) preparing a reaction mixture in one or more solvents, the reaction mixture containing sodium borohydride, at least one ammonium salt, and ammonia; and (b) incubating the reaction mixture at temperatures between about 0.degree. C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. Methods for synthesizing ethylenediamine bisborane, and methods for dehydrogenation of ethylenediamine bisborane are also described.

Blood ammonia and glutamine as predictors of hyperammonemic crises in patients with urea cycle disorder.

Science.gov (United States)

Lee, Brendan; Diaz, George A; Rhead, William; Lichter-Konecki, Uta; Feigenbaum, Annette; Berry, Susan A; Le Mons, Cindy; Bartley, James A; Longo, Nicola; Nagamani, Sandesh C; Berquist, William; Gallagher, Renata; Bartholomew, Dennis; Harding, Cary O; Korson, Mark S; McCandless, Shawn E; Smith, Wendy; Cederbaum, Stephen; Wong, Derek; Merritt, J Lawrence; Schulze, Andreas; Vockley, Jerry; Vockley, Gerard; Kronn, David; Zori, Roberto; Summar, Marshall; Milikien, Douglas A; Marino, Miguel; Coakley, Dion F; Mokhtarani, Masoud; Scharschmidt, Bruce F

2015-07-01

The aim of this study was to examine predictors of ammonia exposure and hyperammonemic crises in patients with urea cycle disorders. The relationships between fasting ammonia, daily ammonia exposure, and hyperammonemic crises were analyzed in >100 patients with urea cycle disorders. Fasting ammonia correlated strongly with daily ammonia exposure (r = 0.764; P 200% (P urea cycle disorder subtype, dietary protein intake, or blood urea nitrogen. Fasting glutamine correlated weakly with daily ammonia exposure assessed as 24-hour area under the curve and was not a significant predictor of hyperammonemic crisis. Fasting ammonia correlates strongly and positively with daily ammonia exposure and with the risk and rate of hyperammonemic crises, suggesting that patients with urea cycle disorder may benefit from tight ammonia control.

Recovery of gold from solutions with ammonia and thiosulfate using activated carbon

OpenAIRE

Vargas, C.; Navarro, Patricio; Araya, Eyleen; Pávez, F.; Alguacil, Francisco José

2006-01-01

The recovery of gold from solutions containing thiosulfate and ammonia using granular activated carbon was studied, evaluating the adsorption and elution stages. The influence of ammonia and thiosulfate concentration and the presence of impurities such as copper and zinc were also evaluated. In the presence of ammonia there was a concentration which maximized the adsorption of gold, while thiosulfate and impurities presence was harmful for the adsorption of gold. During elution, ammonia and t...

AMINA-chip : a miniaturized measurement system for ambient ammonia

NARCIS (Netherlands)

Timmer, Björn Herman

2004-01-01

The development of a miniaturized and integrated measurement system for gaseous ammonia is described in this thesis. The measuring principle, ¿AMINA¿, is an indirect method for selectively measuring ammonia that makes use of pH-transitions, electrolyte conductivity detection and phaseseparating

Applicability of Ammonia Sensors for Controlling Environmental Parameters in Accommodations for Lamb Fattening

Directory of Open Access Journals (Sweden)

F. Javier García-Ramos

2018-01-01

Full Text Available Electrochemical ammonia sensors were used to analyse the existing relationship between the ammonia concentration and ambient levels of both temperature and relative humidity in commercial lamb fattening housing equipped with mechanical ventilation and straw-bedded pens. In the first stage of the experiment, sensors were placed over straw beds covered in lamb urine and analysed under laboratory conditions in order to determine ammonia emission evolution over time; three control temperatures (25, 35, and 50°C were used. A HOBO H8 temperature and relative humidity logger and a Dräger NH3LC-6809680 electrochemical ammonia sensor placed in a Dräger Polytron 7000 gas detector were utilized as sensors. A positive correlation was established between both ammonia emission time and emitted amount with temperature. Additionally, tests were performed in a commercial lamb housing to determine ammonia concentration variation with respect to height from the ground; three ammonia sensors placed at 50, 90, and 135 cm above the ground were used simultaneously. The ammonia concentration significantly decreased as height increased. A 90 cm height was selected, and three ammonia probes were placed in three different pens inside the livestock housing, along with temperature and relative humidity sensors; four different housing ventilation rates were then tested under real conditions over a time period of 4 months. An adjustment polynomial equation between the housing ambient temperature and the ammonia concentration was obtained with R2 = 0.632. In conclusion, a relationship can be established between temperature and ammonia concentration in commercial lamb housing under certain handling conditions, which in turn allows for estimating the ammonia concentration adequately based on the ambient internal temperature.

Mobility Spectrometer Studies on Hydrazine and Ammonia Detection

Science.gov (United States)

Niu, William; Eiceman, Gary; Szumlas, Andrew; Lewis, John

2011-01-01

An airborne vapor analyzer for detecting sub- to low- parts-per-million (ppm) hydrazine in the presence of higher concentration levels of ammonia has been under development for the Orion program. The detector is based on ambient pressure ionization and ion mobility characterization. The detector encompasses: 1) a membrane inlet to exclude particulate and aerosols from the analyzer inlet; 2) a method to separate hydrazine from ammonia which would otherwise lead to loss of calibration and quantitative accuracy for the hydrazine determination; and 3) response and quantitative determinations for both hydrazine and ammonia. Laboratory studies were made to explore some of these features including mobility measurements mindful of power, size, and weight issues. The study recommended the use of a mobility spectrometer of traditional design with a reagent gas and equipped with an inlet transfer line of bonded phase fused silica tube. The inlet transfer line provided gas phase separation of neutrals of ammonia from hydrazine at 50 C simplifying significantly the ionization chemistry that underlies response in a mobility spectrometer. Performance of the analyzer was acceptable between ranges of 30 to 80 C for both the pre-fractionation column and the drift tube. An inlet comprised of a combined membrane with valve-less injector allowed high speed quantitative determination of ammonia and hydrazine without cross reactivity from common metabolites such as alcohols, esters, and aldehydes. Preliminary test results and some of the design features are discussed.

A process to remove ammonia from PUREX plant effluents

International Nuclear Information System (INIS)

Moore, J.D.

1990-01-01

Zirconium-clad nuclear fuel from the Hanford N-Reactor is reprocessed in the PUREX (Plutonium Uranium Extraction) Plant operated by the Westinghouse Hanford Comapny. Before dissolution, cladding is chemically removed from the fuel elements with a solution of ammonium fluoride-ammonium nitrate (AFAN). a solution batch with an ammonia equivalent of about 1,100 kg is added to each fuel batch of 10 metric tons. This paper reports on this decladding process, know as the 'Zirflex' process which produces waste streams containing ammonia and ammonium slats. Waste stream treatment, includes ammonia scrubbing, scrub solution evaporation, residual solids dissolution, and chemical neutralization. These processes produce secondary liquid and gaseous waste streams containing varying concentrations of ammonia and low-level concentrations of radionuclides. Until legislative restrictions were imposed in 1987, these secondary streams were released to the soil in a liquid disposal 'crib' and to the atmosphere

Counteracting ammonia inhibition during anaerobic digestion by recovery using submersible microbial desalination cell.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-07-01

Ammonia inhibition is one of the most frequent and serious problems in biogas plants. In this study, a novel hybrid system consisting of a submersible microbial desalination cell (SMDC) and a continuous stirred tank reactor (CSTR) was developed for counteracting ammonia inhibition during anaerobic digestion (AD) with simultaneous in situ ammonia recovery and electricity production. The SMDC was powered by acetate in a buffer solution, while synthetic ammonia-rich wastewater was used as the feeding of the CSTR. Under continuous operation, ammonia recovery rate of 86 g-N/m(2) /day and current density of 4.33 A/m(2) were achieved at steady-state condition. As a result, 112% extra biogas was produced due to ammonia recovery by the SMDC. High-throughput sequencing showed that ammonia recovery had an impact on the microbial community structures in the SMDC and CSTR. Considering the additional economic benefits of biogas enhancement and possible wastewater treatment, the SMDC may represent a cost-effective and environmentally friendly method for waste resources recovery and biomethanation of ammonia-rich residues. © 2015 Wiley Periodicals, Inc.

High Ph, Ammonia Toxicity, and the Search for Life on the Jovian Planets

Science.gov (United States)

Deal, P. H.; Souza, K. A.; Mack, H. M.

1975-01-01

The effects of pH and ammonia concentration were studied separately, where possible, on a variety of organisms, including some isolated from natural environments of high pH and/or ammonia concentration. Escherichia coli and Bacillus subtilis are both extremely sensitive to ammonia. An aerobic organism (growth up to pH 11.4) from an alkaline spring is more resistant, but exhibits a toxic response to ammonia at a pH much lower than its maximum for growth. The greatest ammonia resistance has been found in an unidentified organism growing at near neutral pH. Even in this case, however, urvival at ammonia concentrations reasonably expected on the Jovian planets is measured in hours. This is two to three orders of magnitude longer than for E. coli. Results support the tentative conclusion that contamination of the Jovian planets with terrestrial organisms that can grow is unlikely. However, the range of toxic response noted, coupled with the observation that terrestrial life has not been exposed to high ammonia concentrations for millions of years, suggests that adaptation to greater ammonia tolerance may be possible.

Characterization of Benzoyl Coenzyme A Biosynthesis Genes in the Enterocin-Producing Bacterium “Streptomyces maritimus”

Science.gov (United States)

Xiang, Longkuan; Moore, Bradley S.

2003-01-01

The novel benzoyl coenzyme A (benzoyl-CoA) biosynthesis pathway in “Streptomyces maritimus” was investigated through a series of target-directed mutations. Genes involved in benzoyl-CoA formation were disrupted through single-crossover homologous recombination, and the resulting mutants were analyzed for their ability to biosynthesize the benzoyl-CoA-primed polyketide antibiotic enterocin. Inactivation of the unique phenylalanine ammonia-lyase-encoding gene encP was previously shown to be absolutely required for benzoyl-CoA formation in “S. maritimus”. The fatty acid β-oxidation-related genes encH, -I, and -J, on the other hand, are necessary but not required. In each case, the yield of benzoyl-CoA-primed enterocin dropped below wild-type levels. We attribute the reduced benzoyl-CoA formation in these specific mutants to functional substitution and cross-talk between the products of genes encH, -I, and -J and the enzyme homologues of primary metabolism. Disruption of the benzoate-CoA ligase encN gene did not perturb enterocin production, however, demonstrating that encN is extraneous and that benzoic acid is not a pathway intermediate. EncN rather serves as a substitute pathway for utilizing exogenous benzoic acid. These experiments provide further support that benzoyl-CoA is formed in a novel bacterial pathway that resembles the eukaryotic assembly of benzoyl-CoA from phenylalanine via a β-oxidative path. PMID:12511484

Oxidative destruction of ammonia for restoration of uranium solution mining sites

International Nuclear Information System (INIS)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-02-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

Method for the Determination of Ammonia in Mainstream Cigarette Smoke Using Ion Chromatography.

Directory of Open Access Journals (Sweden)

Christina Vaughan Watson

Full Text Available Ammonia in mainstream smoke is present in both the particulate and vapor phases. The presence of ammonia in the cigarette filler material and smoke is of significance because of the potential role ammonia could have in raising the "smoke pH." An increased smoke pH could shift a fraction of total nicotine to free-base nicotine, which is reportedly more rapidly absorbed by the smoker. Methods measuring ammonia in smoke typically employ acid filled impingers to trap the smoke. We developed a fast, reliable method to measure ammonia in mainstream smoke without the use of costly and time consuming impingers to examine differences in ammonia delivery. The method uses both a Cambridge filter pad and a Tedlar bag to capture particulate and vapor phases of the smoke. We quantified ammonia levels in the mainstream smoke of 50 cigarette brands from 5 manufacturers. Ammonia levels ranged from approximately 1μg to 23μg per cigarette for ISO smoking conditions and 38μg to 67μg per cigarette for Canadian intense smoking conditions and statistically significance differences were observed between brands and manufacturers. Our findings suggest that ammonia levels vary by brand and are higher under Canadian intense smoking conditions.

Ammonia-hydrogen bromide and ammonia-hydrogen iodide complexes: anion photoelectron and ab initio studies.

Science.gov (United States)

Eustis, S N; Whiteside, A; Wang, D; Gutowski, M; Bowen, K H

2010-01-28

The ammonia-hydrogen bromide and ammonia-hydrogen iodide, anionic heterodimers were studied by anion photoelectron spectroscopy. In complementary studies, these anions and their neutral counterparts were also investigated via ab initio theory at the coupled cluster level. In both systems, neutral NH(3)...HX dimers were predicted to be linear, hydrogen-bonded complexes, whereas their anionic dimers were found to be proton-transferred species of the form, (NH(4)(+)X(-))(-). Both experimentally measured and theoretically predicted vertical detachment energies (VDE) are in excellent agreement for both systems, with values for (NH(4)(+)Br(-))(-) being 0.65 and 0.67 eV, respectively, and values for (NH(4)(+)I(-))(-) being 0.77 and 0.81 eV, respectively. These systems are discussed in terms of our previous study of (NH(4)(+)Cl(-))(-).

Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

DEFF Research Database (Denmark)

Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

Substrates that contain high ammonia levels can cause inhibition on anaerobic digestion process and unstable biogas production. The aim of the current study was to assess the effects of different ammonia levels on pure strains of (syntrophic acetate oxidizing) SAO bacteria and hydrogenotrophic...... methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

Study of the effects of proline, phenylalanine, and urea foliar application to Tempranillo vineyards on grape amino acid content. Comparison with commercial nitrogen fertilisers.

Science.gov (United States)

Garde-Cerdán, T; López, R; Portu, J; González-Arenzana, L; López-Alfaro, I; Santamaría, P

2014-11-15

The aim of this work was to study the influence of foliar application of different nitrogen sources on grape amino acid content. The nitrogen sources applied to Tempranillo grapevines were proline, phenylalanine, urea, and two commercial nitrogen fertilisers, both without and with amino acids in their formulations. All treatments were applied at veraison and one week later. Proline treatment did not affect the must nitrogen composition. However, phenylalanine and urea foliar application enhanced the plants' synthesis of most of the amino acids, producing similar effects. In addition, the spray of commercial nitrogen fertilisers over leaves also induced a rise in grape amino acid concentrations regardless of the presence or absence of amino acids in their formulation. The most effective treatments were phenylalanine and urea followed by nitrogen fertilisers. This finding is of oenological interest for improved must nitrogen composition, ensuring better fermentation kinetics and most likely enhancing wine quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ammonia scrubber testing during IDMS SRAT and SME processing. Revision 1

International Nuclear Information System (INIS)

Lambert, D.P.

1995-01-01

This report summarizes results of the Integrated DWPF (Defense Waste Processing Facility) Melter System (IDMS) ammonia scrubber testing during the PX-7 run (the 7th IDMS run with a Purex type sludge). Operation of the ammonia scrubber during IDMS Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processing has been completed. The ammonia scrubber was successful in removing ammonia from the vapor stream to achieve NH3 concentrations far below the 10 ppM vapor exist design basis during SRAT processing. However, during SME processing, vapor NH3 concentrations as high as 450 ppM were measured exiting the scrubber. Problems during the SRAT and SME testing were vapor bypassing the scrubber and inefficient scrubbing of the ammonia at the end of the SME cycle (50% removal efficiency; 99.9% is design basis efficiency)

Counteracting ammonia inhibition during anaerobic digestion by recovery using submersible microbial desalination cell

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

Ammonia inhibition is one of the most frequent and serious problems in biogas plants. In this study, a novel hybrid system consisting of a submersible microbial desalination cell (SMDC) and a continuous stirred tank reactor (CSTR) was developed for counteracting ammonia inhibition during anaerobic...... digestion (AD) with simultaneous in situ ammonia recovery and electricity production. The SMDC was powered by acetate in a buffer solution, while synthetic ammonia-rich wastewater was used as the feeding of the CSTR. Under continuous operation, ammonia recovery rate of 86 g-N/m2 /day and current density...... of 4.33 A/m2 were achieved at steady-state condition. As a result, 112% extra biogas was produced due to ammonia recovery by the SMDC. High-throughput sequencing showed that ammonia recovery had an impact on the microbial community structures in the SMDC and CSTR. Considering the additional economic...

U.S. broiler housing ammonia emissions inventory

Science.gov (United States)

Gates, R. S.; Casey, K. D.; Wheeler, E. F.; Xin, H.; Pescatore, A. J.

Using recently published baseline ammonia emissions data for U.S. broiler chicken housing, we present a method of estimating their contribution to an annual ammonia budget that is different from that used by USEPA. Emission rate increases in a linear relationship with flock age from near zero at the start of the flock to a maximum at the end of the flock, 28-65 days later. Market weight of chickens raised for meat varies from "broilers" weighing about 2 kg to "roasters" weighing about 3 kg. Multiple flocks of birds are grown in a single house annually, with variable downtime to prepare the house between flocks. The method takes into account weight and number of chickens marketed. Uncertainty in baseline emissions estimates is used so that inventory estimates are provided with error estimates. The method also incorporates the condition of litter that birds are raised upon and the varying market weight of birds grown. Using 2003 USDA data on broiler production numbers, broiler housing is estimated to contribute 8.8-11.7 kT ammonia for new and built-up litter, respectively, in Kentucky and 240-324 kT ammonia for new and built-up litter, respectively, nationally. Results suggest that a 10% uncertainty in annual emission rate is expected for the market weight categories of broilers, heavy broilers, and roasters. A 27-47% reduction in annual housing emission rate is predicted if new rather than built-up litter were used for every flock. The estimating method can be adapted to other meat bird building emissions and future ammonia emission strategies, with suitable insertion of an age-dependent emission factor or slope into a predictive model equation. The method can be readily applied and is an alternative to that used by USEPA.

Applicability of Zeolite Based Systems for Ammonia Removal and Recovery From Wastewater.

Science.gov (United States)

Das, Pallabi; Prasad, Bably; Singh, Krishna Kant Kumar

2017-09-01

  Ammonia discharged in industrial effluents bears deleterious effects and necessitates remediation. Integrated systems devoted to recovery of ammonia in a useful form and remediation of the same addresses the challenges of waste management and its utilization. A comparative performance evaluation study was undertaken to access the suitability of different zeolite based systems (commercial zeolites and zeolites synthesized from fly ash) for removal of ammonia followed by its subsequent release. Four main parameters which were studied to evaluate the applicability of such systems for large scale usage are cost-effectiveness, ammonia removal efficiency, performance on regeneration, and ammonia release percentage. The results indicated that synthetic zeolites outperformed zeolites synthesized from fly ash, although the later proved to be more efficient in terms of total cost incurred. Process technology development in this direction will be a trade-of between cost and ammonia removal and release efficiencies.

Recovery of gold from solutions with ammonia and thiosulfate using activated carbon

International Nuclear Information System (INIS)

Vargas, C.; Navarro, P.; Araya, E.; Pavez, F.; Alguacil, F. J.

2006-01-01

The recovery of gold from solutions containing thiosulfate and ammonia using granular activated carbon was studied,evaluating the adsorption and elution stages. The influence of ammonia and thiosulfate concentration and the presence of impurities such as copper and zinc were also evaluated. In the presence of ammonia there was a concentration which maximized the adsorption of gold, while thiosulfate and impurities presence was harmful for the adsorption of gold. during elution, ammonia and thiosulfate concentration, pH regulator and temperature were evaluated. Ammonia favored the process as long as thiosulfate showed a maximum starting from which the elution diminishes. The effect of the pH regulator was very important; If was revealed that when the pH was regulated with caustic ammonia, a synergic effect appeared which favored the elution. Temperature favored the elution process, with activation energy of 9.13 kJ/mol. (Author) 25 refs

Emission of ammonia from indoor concrete wall and assessment of human exposure.

Science.gov (United States)

Bai, Z; Dong, Y; Wang, Z; Zhu, T

2006-04-01

Addition of urea-based antifreeze admixtures during cement mixing can make it possible to produce concrete cement in construction of buildings in cold weather; this, however, has led to increasing indoor air pollution due to continuous transformation and emission from urea to gaseous ammonia in indoor concrete wall. It is believed that ammonia is harmful to human body and exposure to ammonia can cause some serious symptoms such as headaches, burns, and even permanent damage to the eyes and lungs. In order to understand the emission of ammonia from indoor concrete wall in civil building and assess the health risk of people living in these buildings, the experimental pieces of concrete wall were first prepared by concreting cement and urea-based antifreeze admixtures to simulate the indoor wall in civil building in this work. Then environmental chamber was adopted for studying the effect of temperature, relative humility and air exchange rate on emission of ammonia from experimental pieces of concrete wall. Also the field experiment was made at selected rooms in given civil buildings. Exposure and potential dose of adult and children exposed to indoor/outdoor ammonia in summer and in winter are calculated and evaluated by using Scenario Evaluation Approach. The results indicated that high air exchange rate leads to decreased ammonia concentration, and elevation of temperature causes increasing ammonia concentration and volatilizing rate in chamber. The complete emission of ammonia from the wall containing urea-based antifreeze admixtures needs more than 10 years in general. Ventilating or improving air exchange can play a significant role in reducing ammonia concentration in actual rooms in field experiments. Urea-based antifreeze admixtures in concrete wall can give rise to high exposure and potential dose, especially in summer. Generally, adults have a high potential dose than children, while children have personal average dose rate beyond adults in the same

Ammonia corrodes solar modules; Salmiakgeist greift Module an

Energy Technology Data Exchange (ETDEWEB)

Petzold, Katrin

2011-07-01

Ammonia is an aggressive gas produced in animal shelters, which may cause corrosion of solar modules. Various institutions, e.g. DLG and TUeV Rheinland, therefore offer an ammonia test for solar modules. The TUeV Rheinland recently commissioned a walk-in test chamber and now issues an official seal of approval, while the DLG doubts the practical value of the test.

Modelling agro-forestry scenarios for ammonia abatement in the landscape

International Nuclear Information System (INIS)

Bealey, W J; Braban, C F; Famulari, D; Theobald, M R; Reis, S; Sutton, M A; Loubet, B; Reay, D S

2014-01-01

Ammonia emissions from livestock production can have negative impacts on nearby protected sites and ecosystems that are sensitive to eutrophication and acidification. Trees are effective scavengers of both gaseous and particulate pollutants from the atmosphere making tree belts potentially effective landscape features to support strategies aiming to reduce ammonia impacts. This research used the MODDAS-THETIS a coupled turbulence and deposition turbulence model, to examine the relationships between tree canopy structure and ammonia capture for three source types—animal housing, slurry lagoon, and livestock under a tree canopy. By altering the canopy length, leaf area index, leaf area density, and height of the canopy in the model the capture efficiencies varied substantially. A maximum of 27% of the emitted ammonia was captured by tree canopy for the animal housing source, for the slurry lagoon the maximum was 19%, while the livestock under trees attained a maximum of 60% recapture. Using agro-forestry systems of differing tree structures near ‘hot spots’ of ammonia in the landscape could provide an effective abatement option for the livestock industry that complements existing source reduction measures. (paper)

No Tryptophan, Tyrosine and Phenylalanine Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder

OpenAIRE

Bergwerff, C.E.; Luman, M.; Blom, H.J.; Oosterlaan, J.

2016-01-01

Background The aim of the current study was to explore the role of aromatic amino acids (AAAs) in blood in relation to attention-deficit/hyperactivity disorder (ADHD). Given their impact on the synthesis of serotonin and dopamine, decreased concentrations of the AAAs tryptophan, tyrosine and phenylalanine in blood may contribute to the expression of ADHD symptoms. Decreased AAA blood concentrations, in turn, may be related to lowered dietary protein intake or to abnormal AAA catabolism, as ev...

Method for application of nitrogen-15-labeled anhydrous ammonia to small plots

International Nuclear Information System (INIS)

Sanchez, C.A.; Blackmer, A.M.

1987-01-01

A method is described that permits precise application of anhydrous ammonia in bands to plots of the size often used in 15 N-tracer studies. This method involves placing a stainless-steel capillary tube in the soil where the ammonia is to be banded, attaching this tube to a cylinder of ammonia, and then pulling the tube through the soil with deposition of ammonia as an even band. The procedure has marked advantages over previously described methods because it can be used with mixtures of anhydrous ammonia and nitrification inhibitors and because the soil environment at the point of application is representative of the soil environment found when a conventional applicator is used

Gold cementation with zinc powder from leaching solutions with ammonia-thiosulphate

International Nuclear Information System (INIS)

Navarro, P.; Vargas, C.; Alvarez, R.; Alguacil, F. J.

2005-01-01

The cementation of gold with powder of zinc, from solutions with thiosulphate and ammonia, was studied. the variables evaluated were: thiosulphate concentration, ammonia concentration, pH, copper concentration and zinc concentration. the results have revealed the great importance of ammonia/thiosulphate relationship in this process and that the impurities presence like copper and zinc will to inhibit the cementation process. (Author) 16 refs

Branched-chain amino acids increase arterial blood ammonia in spite of enhanced intrinsic muscle ammonia metabolism in patients with cirrhosis and healthy subjects

DEFF Research Database (Denmark)

Dam, Gitte; Keiding, Susanne; Munk, Ole Lajord

2011-01-01

Branched-chain amino acids (BCAA) are used in attempts to reduce blood ammonia in patients with cirrhosis and intermittent hepatic encephalopathy based on the hypothesis that BCAA stimulate muscle ammonia detoxification. We studied the effects of an oral dose of BCAA on the skeletal muscle...

Hydrodynamic analysis and simulation of a flow cell ammonia electrolyzer

International Nuclear Information System (INIS)

Diaz, Luis A.; Botte, Gerardine G.

2015-01-01

Highlights: • NH_3 electrooxidation mechanism was validated in a bench scale electrolyzer. • All kinetic parameters for NH_3 electro-oxidation were calculated and verified. • Hydrodynamic behavior of the NH_3 electrolyzer was properly described as a CSTR. • CSTR model was successfully applied to simulate a flow ammonia electrolyzer. - Abstract: The hydrodynamic analysis and simulation of a non-ideal single pass flow cell alkaline ammonia electrolyzer was performed after the scale-up of a well-characterized deposited polycrystalline Pt on Ni anode. The hydrodynamic analysis was performed using the residence time distribution (RTD) test. The results of the hydrodynamic investigation provide additional insights for the kinetic analysis of the ammonia electrooxidation reaction on polycrystalline Pt electrocatalysts -which are typically obtained under controlled flow regime, e.g., rotating disk electrode- by including the flow non-uniformity present in the electrolyzer. Based on the RTD function, the ammonia electrolyzer performance was simulated as a non-steady stirred tank reactor (CSTR) and the unknown kinetic parameters were obtained by fitting the simulation results with an experimental current profile, obtaining an adequate prediction of the ammonia conversion. This simplified approach for the simulation of the ammonia electrolyzer could be implemented in process simulation packages and could be used for the design and scale-up of the process for hydrogen production and wastewater remediation.

Metal-Ion-Mediated Supramolecular Chirality of l-Phenylalanine Based Hydrogels.

Science.gov (United States)

Wang, Fang; Feng, Chuan-Liang

2018-05-14

For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l-phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abnormal tyrosine and phenylalanine metabolism in patients with tyrosyluria and phenylketonuria; gas-liquid chromatographic analysis of urinary metabolites

NARCIS (Netherlands)

Wadman, S.K.; Heiden, C. van der; Ketting, D.; Sprang, F.J. van

Gas-liquid chromatographic methods have been developed for the analysis of: urinary phenylalanine metabolites (I) in patients with phenylketonuria, tyrosine metabolites (II) in patients with a disturbed tyrosine metabolism at the level of p-hydroxyphenylpyruvate hydroxylase, and homogentisic acid in