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Sample records for acid phosphates

  1. Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids

    Institute of Scientific and Technical Information of China (English)

    XU Ren-kou; ZHU Yong-guan; David Chittleborough

    2004-01-01

    Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by Iow-molecular-weight organic acids.Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the pKa values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was not correlated with PKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearrly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

  2. 21 CFR 182.6085 - Sodium acid phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium acid phosphate. 182.6085 Section 182.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  3. 21 CFR 582.6085 - Sodium acid phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium acid phosphate. 582.6085 Section 582.6085 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium acid phosphate. (a) Product. Sodium acid phosphate. (b) Conditions of use. This substance...

  4. Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

    OpenAIRE

    Qurban Ali Panhwar; Shamshuddin Jusop; Umme Aminun Naher; Radziah Othman; Mohd Ismail Razi

    2013-01-01

    A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed ...

  5. Physical Properties of Acidic Calcium Phosphate Cements

    OpenAIRE

    2014-01-01

    The gold standard for bone replacement today, autologous bone, suffers from several disadvantages, such as the increased risk of infection due to the need for two surgeries. Degradable synthetic materials with properties similar to bone, such as calcium phosphate cements, are a promising alternative. Calcium phosphate cements are suited for a limited amount of applications and improving their physical properties could extend their use into areas previously not considered possible. For example...

  6. Application of potential phosphate-solubilizing bacteria and organic acids on phosphate solubilization from phosphate rock in aerobic rice.

    Science.gov (United States)

    Panhwar, Qurban Ali; Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

    2013-01-01

    A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg(-1)), plant P uptake (0.78 P pot(-1)), and plant biomass (33.26 mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g(-1)) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH.

  7. Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

    Directory of Open Access Journals (Sweden)

    Qurban Ali Panhwar

    2013-01-01

    Full Text Available A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB and organic acids (oxalic & malic on phosphate (P solubilization from phosphate rock (PR and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM, and PSB strain (Bacillus sp. were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1, plant P uptake (0.78 P pot−1, and plant biomass (33.26 mg. Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1 compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH.

  8. Proton transport properties of tin phosphate, chromotropic acid anchored onto tin phosphate and tin phenyl phosphonate

    Indian Academy of Sciences (India)

    Chithra Sumej; P P Sharmila; Nisha J Tharayil; S Suma

    2013-02-01

    Tin (IV) phosphates of the class of tetravalent metal acid (TMA) salts have been synthesized by sol–gel method. The functionalized materials of tin (IV) phosphate (SnP) like chromotropic acid anchored tin phosphate (SnPCA) and tin phenyl phosphonate (SnPP) were also synthesized. These materials have been characterized for elemental analysis (ICP–AES), thermal analysis, X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials has been accessed in acidic, basic and organic solvent media. The proton present in the structural hydroxyl groups indicates good potential for TMA salts to exhibit solid-state proton conduction. The transport properties of these materials have been explored by measuring specific proton conductance at different temperatures. Based on the specific conduction data and Arrhenius plots, a suitable mechanism has been proposed.

  9. Study of Acid Phosphatase in Solubilization of Inorganic Phosphates by Piriformospora indica.

    Science.gov (United States)

    Seshagiri, Swetha; Tallapragada, Padmavathi

    2017-01-02

    Phosphorus is an essential plant macronutrient present in the soil. Only a small portion of phosphorus in soil is taken up by plants and the rest of it becomes unavailable to plants as it is immobilized. Phosphate solubilizing microorganisms play a vital role in converting the insoluble form of phosphates to the soluble form. The present paper reports the solubilization of tricalcium phosphate, rock phosphate, single super phosphate, zinc phosphate and aluminum phosphate by Piriformospora indica with the production of organic acids as well as acid phosphatase. The amount of phosphate released (4.73 mg ml(-1)) and titratable acidity (0.12%) was found to be the highest in the case of single super phosphate as compared to other phosphate sources. High performance liquid chromatography (HPLC) revealed the presence of oxalic acid, lactic acid, citric acid and succinic acid in the media. Highest phosphatase activity was observed with the cell membrane extract of the organism in the presence of zinc phosphate.

  10. Phosphate Rock Fertilizer in Acid Soil:Comparing Phosphate Extraction Methods for Measuring Dissolution

    Institute of Scientific and Technical Information of China (English)

    T.S.ANSUMANA-KAWA; WANGGUANGHUO

    1998-01-01

    Three phosphate extraction methods were used to investigate the dissolution,availability and transfo-mation of Kunyang phosphate rock(KPR) in two surface acid soils.Dissolution was determined by measuring the increase in the amounts of soluble and adsorbed inorganic phosphate fractions,and did not differ signifi-cantly among the three methods.Significant correlations were obtained among P fractions got by the three extraction methods.Dissolution continued until the end of the 90-day incubation period.At the end of the period,much of the applied phosphate recovered in both soils were in the Al- and Fe-P or in the hydroxide-and bicarbonate-extractable inorganic P fractions.The dissolution of KPR in the two soils was also similar: increased addition of phosphate rock resulted in decreased dissolution.The similarity in the order and extent of dissolution in the two soils was probably due to the similarity in each soil of several factors that are known to influence phosphate rock dissolution,namely low CEC,pH,P level,and base status;and high clay and free iron and aluminum oxide contents.The results suggested that KPR could be an aternative P source in the soils are not limiting.

  11. Reaction of Thymidine with Hypobromous Acid in Phosphate Buffer.

    Science.gov (United States)

    Suzuki, Toshinori; Kitabatake, Akihiko; Koide, Yuki

    2016-01-01

    When thymidine was treated with hypobromous acid (HOBr) in 100 mM phosphate buffer at pH 7.2, two major product peaks appeared in the HPLC chromatogram. The products in each peak were identified by NMR and MS as two isomers of 5-hydroxy-5,6-dihydrothymidine-6-phosphate (a novel compound) and two isomers of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol) with comparable yields. 5-Hydroxy-5,6-dihydrothymidine-6-phosphate was relatively stable, and decomposed with a half-life of 32 h at pH 7.2 and 37°C generating thymidine glycol. The results suggest that 5-hydroxy-5,6-dihydrothymidine-6-phosphate in addition to thymidine glycol may have importance for mutagenesis by the reaction of HOBr with thymine residues in nucleotides and DNA.

  12. Soluble phosphate fertilizer production using acid effluent from metallurgical industry.

    Science.gov (United States)

    Mattiello, Edson M; Resende Filho, Itamar D P; Barreto, Matheus S; Soares, Aline R; Silva, Ivo R da; Vergütz, Leonardus; Melo, Leônidas C A; Soares, Emanuelle M B

    2016-01-15

    Preventive and effective waste management requires cleaner production strategies and technologies for recycling and reuse. Metallurgical industries produce a great amount of acid effluent that must be discarded in a responsible manner, protecting the environment. The focus of this study was to examine the use of this effluent to increase reactivity of some phosphate rocks, thus enabling soluble phosphate fertilizer production. The effluent was diluted in deionized water with the following concentrations 0; 12.5; 25; 50; 75% (v v(-1)), which were added to four natural phosphate rocks: Araxá, Patos, Bayovar and Catalão and then left to react for 1 h and 24 h. There was an increase in water (PW), neutral ammonium citrate (PNAC) and citric acid (PCA) soluble phosphorus fractions. Such increases were dependent of rock type while the reaction time had no significant effect (p < 0.05) on the chemical and mineralogical phosphate characteristics. Phosphate fertilizers with low toxic metal concentrations and a high level of micronutrients were produced compared to the original natural rocks. The minimum amount of total P2O5, PNAC and PW, required for national legislation for phosphate partially acidulated fertilizer, were met when using Catalão and the effluent at the concentration of 55% (v v(-1)). Fertilizer similar to partially acidulated phosphate was obtained when Bayovar with effluent at 37.5% (v v(-1)) was used. Even though fertilizers obtained from Araxá and Patos did not contain the minimum levels of total P2O5 required by legislation, they can be used as a nutrient source and for acid effluent recycling and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. application of ascorbic acid 2-phosphate as a new voltammetric ...

    African Journals Online (AJOL)

    a

    acid 2-phosphate (AAP) as a new voltammetric substrate has been ... further applied to determine the ALP content in healthy human serum and the results were in ... substrates to produce phenol or p-aminophenol, which is electroactive and can be ... bovine serum, human serum and untreated human blood with the linear ...

  14. Electrodialysis of Phosphates in Industrial-Grade Phosphoric Acid

    OpenAIRE

    Machorro, J. J.; Olvera, J. C.; Larios, A.; Hernández-Hernández, H. M.; Alcantara-Garduño, M. E.; Orozco, G.

    2013-01-01

    The objective of this research was to study the purification of industrial-grade phosphoric acid (P2O5) by conventional electrodialysis. The experiments were conducted using a three-compartment cell with anion and cation membranes, and industrial acid solution was introduced into the central compartment. The elemental analysis of the diluted solution indicated that the composition of magnesium, phosphates, and sodium was reduced in the central compartment. The ratios of the concentration of t...

  15. Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.

    Science.gov (United States)

    Su, Gaomin; Jiao, Kailin; Li, Zheng; Guo, Xiaoyi; Chang, Jingyu; Ndikubwimana, Theoneste; Sun, Yong; Zeng, Xianhai; Lu, Yinghua; Lin, Lu

    2016-07-01

    Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2 g/L), temperature (25, 30 and 33 °C) and phosphate (0.00-0.14 g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8 g/L and moderate temperature of 30 °C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38 mg/L and ARA yield of 159.74 mg/L were obtained at a phosphate concentration of 0.035 g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA.

  16. Comparison of efficacy of the phosphate binders nicotinic acid and sevelamer hydrochloride in hemodialysis patients

    National Research Council Canada - National Science Library

    Ahmadi, Farrokhlagha; Shamekhi, Fatemeh; Lessan-Pezeshki, Mahbob; Khatami, Mohammad Reza

    2012-01-01

    ...), and must be controlled with the use of phosphate binders. Studies comparing the effects of sevelamer and nicotinic acid, both similar non-calcium and non-aluminum phosphate binders, are not available...

  17. Arsenic removal from contaminated soil using phosphoric acid and phosphate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Laboratory batch experiments were conducted to study Arsenic (As) removal from a naturally contaminated soil using phosphoric acid (H3PO4) and potassium dihydrogen phosphate (KH2PO4). Both H3PO4 and KH2PO4 proved to clearly reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L, although soil As tolerance limit of 30 mg/kg, according to Chinese Environmental quality standard for soil (EQSS), was not satisfied by using these two extractants. At the same time, acidification of soil and dissolution of soil components (Ca, Mg, and Si) resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions (PO43-). The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 min, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich's model best described the kinetic data of As removal among the four models used in the kinetic study.

  18. Permeability of lipid bilayers to amino acids and phosphate

    Science.gov (United States)

    Chakrabarti, A. C.; Deamer, D. W.

    1992-01-01

    Permeability coefficients for amino acid classes, including neutral, polar, hydrophobic, and charged species, were measured and compared with values for other ionic solutes such as phosphate. The rates of efflux of glycine, lysine, phenylalanine, serine and tryptophan were determined after they were passively entrapped in large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine (EPC) or dimyristoylphosphatidylcholine (DMPC). The following permeability coefficients were obtained for: glycine, 5.7 x 10(-12) cm s-1 (EPC), 2.0 x 10(-11) cm s-1 (DMPC); serine, 5.5 x 10(-12) cm s-1 (EPC), 1.6 x 10(-11) cm s-1 (DMPC); lysine, 5.1 x 10(-12) cm s-1 (EPC), 1.9 x 10(-11) cm s-1 (DMPC); tryptophan, 4.1 x 10(-10) cm s-1 (EPC); and phenylalanine, 2.5 x 10(-10) cm s-1 (EPC). Decreasing lipid chain length increased permeability slightly, while variations in pH had only minor effects on the permeability coefficients of the amino acids tested. Phosphate permeability was in the range of 10(-12)-10(-13) cm s-1 depending on the pH of the medium. The values for the polar and charged amino acids were surprisingly similar to those previously measured for monovalent cations such as sodium and potassium, which are in the range of 10(-12)-10(-13) cm s-1, depending on conditions and the lipid species used. This observation suggests that the permeation rates for the neutral, polar and charged amino acids are controlled by bilayer fluctuations and transient defects, rather than partition coefficients and Born energy barriers. The results are relevant to the permeation of certain peptides into lipid bilayers during protein translocation and membrane biogenesis.

  19. Fact Sheet - Phosphate Fertilizer Production Plants and Phosphoric Acid Manufacturing Plants NESHAP

    Science.gov (United States)

    Fact sheet summarizing National Emission Standards for Hazardous Air Pollutants (NESHAP) for Phosphate Fertilizer Production Plants and Phosphoric Acid Manufacturing Plants (40 CFR 63 Subparts AA and BB).

  20. Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas

    Directory of Open Access Journals (Sweden)

    Vyas Pratibha

    2009-08-01

    Full Text Available Abstract Background Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acids during inorganic phosphate solubilization and influence on plant growth as a function of phosphate solubilization by fluorescent Pseudomonas. Results Nineteen phosphate-solubilizing fluorescent Pseudomonas strains of P. fluorescens, P. poae, P. trivialis, and Pseudomonas spp. produced gluconic acid, oxalic acid, 2-ketogluconic acid, lactic acid, succinic acid, formic acid, citric acid and malic acid in the culture filtrates during the solubilization of tricalcium phosphate, Mussoorie rock phosphate, Udaipur rock phosphate and North Carolina rock phosphate. The strains differed quantitatively and qualitatively in the production of organic acids during solubilization of phosphate substrates. Cluster analysis based on organic acid profiling revealed inter-species and intra-species variation in organic acids produced by Pseudomonas strains. The phosphate-solubilizing bacterial treatments P. trivialis BIHB 745, P. trivialis BIHB 747, Pseudomonas sp. BIHB 756 and P. poae BIHB 808 resulted in significantly higher or statistically at par growth and total N, P and K content over single super phosphate treatment in maize. These treatments also significantly affected pH, organic matter, and N, P, and K content of the soil. Conclusion The results implied that organic acid production by Pseudomonas strains is independent of their genetic relatedness and each strain has its own ability of producing organic acids during the solubilization of inorganic phosphates

  1. Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid.

    Science.gov (United States)

    Su, Xiaojuan; Zhu, Jun; Fu, Qingling; Zuo, Jichao; Liu, Yonghong; Hu, Hongqing

    2015-02-01

    Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120 days was reduced by 100% when soils were amended with APR, HAP and HAP+OA, and the TCLP-Pb was phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.

  2. Unique roles of acidic amino acids in phase transformation of calcium phosphates.

    Science.gov (United States)

    Chu, Xiaobin; Jiang, Wenge; Zhang, Zhisen; Yan, Yang; Pan, Haihua; Xu, Xurong; Tang, Ruikang

    2011-02-10

    Although phase transformation is suggested as a key step in biomineralization, the chemical scenario about how organic molecules mediate inorganic phase transformations is still unclear. The inhibitory effect of amino acids on hydroxyapatite (HAP, the main inorganic component of biological hard tissues such as bone and enamel) formation was concluded by the previous biomimetic modeling based upon direct solution crystallization. Here we demonstrate that acidic amino acids, Asp and Glu, could promote HAP crystallization from its precursor crystal, brushite (DCPD). However, such a promotion effect could not be observed when the nonacidic amino acids were applied in the transformation-based HAP formation. We found that the specific modification of acidic amino acid on crystal-solution interfaces played a key role in the phase transition. The distinct properties between DCPD and HAP in the solution resulted in an interfacial energy barrier to suppress the spontaneous formation of HAP phase on DCPD phase. Different from the other amino acids, the carboxylate-rich amino acids, Asp and Glu, could modify the interfacial characteristics of these two calcium phosphate crystals to make them similar to each other. The experiments confirmed that the involvement of Asp or Glu reduced the interfacial energy barrier between DCPD and HAP, leading to a trigger effect on the phase transformation. An in-depth understanding about the unique roles of acidic amino acids may contribute to understanding phase transformation controls druing biomineralization.

  3. Interaction between phosphate and acid-activated neutralized red mud during adsorption process

    Science.gov (United States)

    Ye, Jie; Cong, Xiangna; Zhang, Panyue; Hoffmann, Erhard; Zeng, Guangming; Liu, Yang; Fang, Wei; Wu, Yan; Zhang, Haibo

    2015-11-01

    Acid-activated neutralized red mud (AaN-RM) has become a promising adsorbent for phosphate adsorption. The maximum phosphate adsorption capacity of AaN-RM reached 492.46 mg g-1 in this study, which was much higher than that of many other adsorbents. However, no study has specifically investigated how the phosphate reacted with AaN-RM. For the first time the interaction between phosphate and AaN-RM during adsorption process was investigated in this research. Kinetic models and isotherms were used to analyze the possible reaction pathways between AaN-RM and phosphate. Particularly, the phosphate complexes on AaN-RM surface, and the exact role of different adsorption mechanisms were systemically identified. The phosphate adsorption was well described by pseudo second-order kinetic model and Langmuir-Freundlich isotherm, which suggested that chemisorption occurred between the phosphate and AaN-RM, and the phosphate adsorption was governed by heterogeneous processes. Furthermore, the phosphate complexes of Fe-P, Al-P, Fe-P-H3PO4 and Al-P-H3PO4 were formed on AaN-RM surface through ion exchange, precipitation and surface deposition mechanisms. XPS analysis of P 2p peak showed that 59.78% of the phosphate was adsorbed through the ion exchange and precipitation with strong chemical bonds, and 40.22% was adsorbed through the surface deposition with weak chemical bonds.

  4. Cationic and radical intermediates in the acid photorelease from aryl sulfonates and phosphates.

    Science.gov (United States)

    Terpolilli, Marco; Merli, Daniele; Protti, Stefano; Dichiarante, Valentina; Fagnoni, Maurizio; Albini, Angelo

    2011-01-01

    The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (≈0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with phosphates and (mainly) radical with sulfonates.

  5. Agronomic Potential of Partially Acidulated Rock Phosphates in Acid Soils of Subtropical China

    Institute of Scientific and Technical Information of China (English)

    XIONGLI-MING; B.TRUONG; 等

    1995-01-01

    A glasshouse experiment was conducted to evaluate the agronomic potential of four partially acidulated rock phosphates(PARP) in three representative solis sampled from subtripical China.The PARPs were manufactured by attacking a moderately reactive phosphate rock either with sulfuric acid alone or with combination of sulfuric and phosphoric acids at 30 or 60 percent of acidulation.Shoot dry weight and P accumulation of six successive cuttings of ryegrass were used to compare the agronomic potential of these fertilizers with that of the raw rock phosphate(RP) and monocalcium phosphate (MCP).Results indicated that the effectiveness of various phosphates was determined both by the solubility of the phosphates and by the acidity and P-fixing capacity of the soils.The higher the watersoluble P contained,the better the effectiveness of the fertilizer was.Although plant P accumulation of PARP treatments was constantly lower than that of MCP treatment,some PARPs could still get a dry matter production similar to that of MCP treatment.PARP SP60,which was acidulated with a mixture of sulfuric acid and phosphoric acid at 60 percent of acidulation and contained the highest soluble,P,was as effective as MCP in terms of dry matter production on all the soils.S60 and C1 which were both acidulated with sulfuric acid with the former at 60 percent of acidulation and the latter at 30 percent but with a further addition of monoammonium phosphate,were more than 80 percent as efective as MCP,Raw RP also showed a reasonable effectiveness which increased with soil acidity.It was suggested from the study that some of these APRPs could be expected to have a comparable field performance as soluble P fertilizers in the acid soil regions.

  6. Mineral phosphate solubilization by Streptomyces sp. CTM396 involves the excretion of gluconic acid and is stimulated by humic acids.

    Science.gov (United States)

    Farhat, Mounira Ben; Boukhris, Ines; Chouayekh, Hichem

    2015-03-01

    The actinomycetes isolates (128) which were taken from agricultural soil samples and collected near a rock phosphate processing unit were screened for mineral phosphate-solubilizing (MPS) ability. A significant MPS activity was observed for 30 isolates on various phosphate sources when grown in the National Botanical Research Institute's phosphate broth. CTM396 and CTM397 strains which showed the highest MPS abilities were identified by 16S rDNA sequencing as members of the genus Streptomyces. Their MPS activity was proved to be concomitant with a drop in pH due to the secretion of gluconic acid (GA). This was correlated with the simultaneous detection by PCR of genes gdh [encoding the glucose dehydrogenase (GDH) responsible for GA production from glucose] and pqq (involved in biosynthesis of the pyrroloquinoline quinone cofactor of GDH), as well as the highlighting of GHD enzyme activity, for the first time in a Streptomyces sp. strain producing GA. Furthermore, the 0.05% of humic acids proved to have a stimulatory effect on the growth and the ability of CTM396 to solubilize Gafsa rock phosphate. According to this study, it is possible to use humic acids and Gafsa rock phosphate in association with spores of ad hoc Streptomyces strains as natural and efficient amendments to improve plant growth with no need of costly and pollutant transformation of Gafsa rock phosphate.

  7. Dehydration of lactic acid to acrylic acid over lanthanum phosphate catalysts: the role of Lewis acid sites.

    Science.gov (United States)

    Guo, Zhen; Theng, De Sheng; Tang, Karen Yuanting; Zhang, Lili; Huang, Lin; Borgna, Armando; Wang, Chuan

    2016-09-14

    Lanthanum phosphate (LaP) nano-rods were synthesized using n-butylamine as a shape-directing agent (SDA). The resulting catalysts were applied in the dehydration of lactic acid to acrylic acid. Aiming to understand the nature of the active sites, the chemical and physical properties of LaP materials were studied using a variety of characterization techniques. This study showed that the SDA not only affected the porosity of the LaP materials but also modified the acid-base properties. Clearly, the modification of the acid-base properties played a more critical role in determining the catalytic performance than porosity. An optimized catalytic performance was obtained on the LaP catalyst with a higher concentration of Lewis acid sites. Basic sites showed negative effects on the stability of the catalysts. Good stability was achieved when the catalyst was prepared using the appropriate SDA/La ratio.

  8. Synthesis of Mesoporous, Nanocrystalline Lanthanum Phosphate in the Presence of Citric Acid and Stearic Acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lanthanum phosphate was prepared in the presence of citric acid and stearic acid under methanolic conditions at pH 4.5 and pH 7, respectively.The samples obtained were intensively characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm study, transmission electron microscopy (TEM), thermal gravimetric and differential thermal analysis, and Fourier transform infrared (FTIR) analysis .The as-synthesized samples prepared at pH 4.5 showed lamellar mesostructured form with high crystallinity.Results showed that the pore size and pore volume changed when the materials were prepared under different pH conditions.Morphology of the samples was observed by using TEM, which showed that the samples possessed relatively small particles closely packed together.The as-synthesized samples were investigated using FTIR, and the mesopore formation mechanism was discussed.

  9. Comparison of acidulated phosphate fluoride gel and hydrofluoric acid etchants for porcelain-composite repair.

    Science.gov (United States)

    Tylka, D F; Stewart, G P

    1994-08-01

    Hydrofluoric acid etches porcelain to produce a porous surface visible under scanning electron microscopy when compared to an acidulated phosphate fluoride gel. Some investigators have suggested the greater porosity of the hydrofluoric acid etch produces a greater composite-to-porcelain bond. This investigation tested that assumption with two common fluoride etchants. The etched surfaces were first viewed under scanning electron microscopy to ensure that a characteristic etch was achieved. Both etchants yielded bond strengths that produced cohesive failure of all samples. This suggested that the intraoral use of hydrofluoric acid is no more effective than the less dangerous acidulated phosphate fluoride gel.

  10. Synthesis and properties of carbohydrate-phosphate backbone-modified oligonucleotide analogues and nucleic acid mimetics

    Energy Technology Data Exchange (ETDEWEB)

    Abramova, Tatyana V; Silnikov, Vladimir N [Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences (Russian Federation)

    2011-05-31

    Advances in the synthesis of oligo(deoxy)ribonucleotide analogues and nucleic acid mimetics made in the last decade are summarized. Attention is focused on new methods for the synthesis of derivatives with a modified ribose-phosphate backbone (phosphorothioate, boranophosphate, and nucleoside phosphonate derivatives) and derivatives devoid of the phosphate group. Among nucleic acid mimetics, conformationally restricted modified peptide nucleic acids, including those bearing a negative or positive charge, and morpholino oligomers are considered. Advantages and drawbacks of the main types of analogues as regards the complexity of the synthesis and the possibility of their application as antisense agents or reagents for hybridization analysis are compared.

  11. Synthesis and properties of carbohydrate-phosphate backbone-modified oligonucleotide analogues and nucleic acid mimetics

    Science.gov (United States)

    Abramova, Tatyana V.; Silnikov, Vladimir N.

    2011-05-01

    Advances in the synthesis of oligo(deoxy)ribonucleotide analogues and nucleic acid mimetics made in the last decade are summarized. Attention is focused on new methods for the synthesis of derivatives with a modified ribose-phosphate backbone (phosphorothioate, boranophosphate, and nucleoside phosphonate derivatives) and derivatives devoid of the phosphate group. Among nucleic acid mimetics, conformationally restricted modified peptide nucleic acids, including those bearing a negative or positive charge, and morpholino oligomers are considered. Advantages and drawbacks of the main types of analogues as regards the complexity of the synthesis and the possibility of their application as antisense agents or reagents for hybridization analysis are compared.

  12. Selective removal of phosphate for analysis of organic acids in complex samples.

    Science.gov (United States)

    Deshmukh, Sandeep; Frolov, Andrej; Marcillo, Andrea; Birkemeyer, Claudia

    2015-04-03

    Accurate quantitation of compounds in samples of biological origin is often hampered by matrix interferences one of which occurs in GC-MS analysis from the presence of highly abundant phosphate. Consequently, high concentrations of phosphate need to be removed before sample analysis. Within this context, we screened 17 anion exchange solid-phase extraction (SPE) materials for selective phosphate removal using different protocols to meet the challenge of simultaneous recovery of six common organic acids in aqueous samples prior to derivatization for GC-MS analysis. Up to 75% recovery was achieved for the most organic acids, only the low pKa tartaric and citric acids were badly recovered. Compared to the traditional approach of phosphate removal by precipitation, SPE had a broader compatibility with common detection methods and performed more selectively among the organic acids under investigation. Based on the results of this study, it is recommended that phosphate removal strategies during the analysis of biologically relevant small molecular weight organic acids consider the respective pKa of the anticipated analytes and the detection method of choice. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Precipitation of calcium phosphate from moderately acid solution

    Science.gov (United States)

    Lundager Madsen, H. E.; Thorvardarson, G.

    1984-04-01

    The precipitation of calcium phosphate upon mixing of equimolar amounts of calcium nitrate and ammonium phosphate has been studied in the temperature range 40-60°C and pH 3.5-6.5. At the lowertemperatures, brushite, CaHPO 4, 2 H 2O, is the major crystalline product. Monetite, CaHPO 4, is formed at the higher temperatures and above a certain critical supersaturation, and OCP, Ca 4H(PO 4) 3.2.5H 2O, in the higher pH range. A metastable, amorphous tricalcium phosphate, Ca 3(PO 4) 2. xH2O, is formed initially if a(Ca 2+) 3a(PO 3-4) 2 exceeds a certain value, which decreases rapidly as temperature increases. The range in which brushite is found as the only crystalline phase narrows with increasing temperature. The results are explained in terms of heterogeneous nucleation for brushite and homogeneous nucleation for monetite.

  14. Gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium Azospirillum spp.

    Science.gov (United States)

    Rodriguez, Hilda; Gonzalez, Tania; Goire, Isabel; Bashan, Yoav

    2004-11-01

    In vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria A. brasilense (Cd and 8-I) and one strain of A. lipoferum JA4 were studied. Strains of A. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. At the same time, there is a reduction in pH of the medium and release of soluble phosphate. To a greater extent, gluconic acid production and pH reduction were observed for A. lipoferum JA4. For the three strains, clearing halos were detected on solid medium plates with calcium phosphate. This is the first report of in vitro gluconic acid production and direct phosphate solubilization by A. brasilense and the first report of P solubilization by A. lipoferum. This adds to the very broad spectrum of plant growth-promoting abilities of this genus.

  15. Setting mechanisms of an acidic premixed calcium phosphate cement

    OpenAIRE

    2013-01-01

    Premixed calcium phosphate cements (pCPC), where glycerol is used instead of water as mixing liquid, present better handling characteristics than water-based cements. However, the setting mechanisms of pCPC have not been described thoroughly. The aim of this paper is to increase the understanding of the setting mechanism of pCPC. The investigated cement starts to set when glycerol is exchanged with water via diffusion of glycerol out to the surrounding body fluid and water into the material. ...

  16. The effects of citric acid on the hydration of calcium phosphate cement

    Institute of Scientific and Technical Information of China (English)

    DAI Hong-lian; YAN Yu-hua; WANG You-fa; LI Shi-pu

    2001-01-01

    @@ INTRODUCTION Calcium phosphate cements (CPC) overcome the practical disadvantages of blocks or granulesl can be handled as a paste and sit in situ. Their structure and composition close to that of HAP make them biocompatible materials. 2 The conventional calcium phosphate cement had some problems such as long setting time (30~60 min) and low compressive strength, etc. In our system, an α-TCP/TTCP powder mixture was mixed with water containing citric acid to control the setting time and compressive strength. In this paper, the effects of various concentration citric acid solutions on the properties of the cement are reported.

  17. Beneficiation of Iraqi Akash at Phosphate Ore Using Organic Acids for the Production of Wet Process Phosphoric Acid

    Directory of Open Access Journals (Sweden)

    Mohammed Y. Eisa

    2013-12-01

    Full Text Available In the present work, leaching process studiedusing organic acids (acetic acid and lactic acid to extract phosphate from the Iraqi Akashat phosphate ore by separation of calcareous materials (mainly calcite. This approach characterized by energy conservation, environmental enhancement by recovery of calcite as calcium sulfate (gypsum, keeping the physical and chemical properties of apatite. Samples were analyzed using X-ray diffraction and FTIR spectrophotometer. From the obtained experimental data it was found that using the two organic acids yields closed purity values of the produced apatite at the optimum conditions, while at different acid concentrations, it was found that the efficiency of acetic acid is higher at the low acid concentration (2 wt%, and that lactic acid gives the higher efficiency at high acid concentration (10 wt%.Concerning the ratio of acid volume to ore weight ratio, it was found that reducing this ratio to 5 ml/gm cause an increase in the purity of apatite at the optimum concentrations of the two acids. In addition, it was found that the reaction ofthe two organic acids with the calcareous material are fast and that the optimum reaction time, in which high purity apatite produced is 10 minutes.

  18. Biocompatibility and degradation of poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composites

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2005-01-01

    Injectable calcium phosphate (Ca-P) cement materials exhibit favorable osteocompatible behavior but are resorbed slowly because of a lack of a bone ingrowth-enabling macroporosity. In this study, poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (average size 66 +/- 25 microm) were incorporated

  19. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. II. ACID AND GENERAL BASE CATALYZED HYDROLYSIS

    Science.gov (United States)

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate acid and neutral hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition states of a ...

  20. Biocompatibility and degradation of poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composites

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2005-01-01

    Injectable calcium phosphate (Ca-P) cement materials exhibit favorable osteocompatible behavior but are resorbed slowly because of a lack of a bone ingrowth-enabling macroporosity. In this study, poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (average size 66 +/- 25 microm) were incorporated

  1. Basic properties of calcium phosphate cement containing different concentrations of citric acid solution

    Institute of Scientific and Technical Information of China (English)

    戴红莲; 闫玉华; 冯凌云; 李世普; 贺建华

    2002-01-01

    The properties of calcium phosphate cement consisting of α-tricalcium phosphate (α-TCP) and tetracalcium phosphate (TTCP) have been investigated by using a cement liquid that contained citric acid with concentration of 0.05 mol/L or higher. The relationship between the setting time of the system cement and the concentration of citric acid solution shows concave type curve. When solution concentration was 0.2 mol/L, the setting time was 8 min, which was the shortest. While the relationship between 24 h compressive strength of the cement and the citric acid concentration shows convex type curve. When solution concentration was 0.2 mol/L, the compressive strength was 39.0 MPa, which was the highest. Afterwards, the microstructure of the hardening product was observed by SEM, the effect of citric acid on the exothermic rate of hydrate reaction was studied by microcalorimeter, and the crushed specimens were subjected to X-ray diffraction. The results verified that the low citric acid concentration can accelerate the hydrate reaction rate of the α-TCP/TTCP system. However, the high citric acid concentration inhibited hydroxyapatite formation and retarded the rate of hydrate reaction of the α-TCP/TTCP cement.

  2. Enhancing phosphate adsorption capacity of SDS-based magnetite by surface modification of citric acid

    Science.gov (United States)

    Yu, Zhigang; Zhang, Chang; Zheng, Zuhong; Hu, Liang; Li, Xuemei; Yang, Zhongzhu; Ma, Chi; Zeng, Guangming

    2017-05-01

    In this study, citric acid (CA) was employed as a low-molecule organic acid to influence the adsorption performance of phosphorus by as-obtained magnetite. The factors including initial phosphate concentrations, dosage of citric acid, pH value, ion strength, contact time and temperature were examined in detail. Results indicated that the dissolution of anion sodium dodecyl sulfate (SDS) covering on surface of magnetite, a slight decrease of Fe level and a superior structure of magnetite after CA modification occurred. The pH-dependence of phosphate adsorption was impeded and the surface potential of magnetite positively increased at pH > 5.0 when CA was added. Non-linear regression Langmuir-Freundlich model was fitted well in thermodynamics, and the opposite adsorption process as a function of temperatures with or without CA addition was due to the decrease of active energy and active mobility of phosphate ion. Finally, the declining adsorption efficiency with increasing cycles was observed while phosphate removal was approximately finished and had small change with 0.05 and 0.1 M of CA addition. Those improvements of removal efficiency of phosphorus by modified iron oxide were because of the removal of anionic SDS that increased the surface positive charge, and especially the dissolution of element Fe into solution to form precipitate with phosphorus ions. The enhanced stability of magnetite by CA also promoted the high removal efficiency of phosphorus. These implications of CA on phosphate removal can be extended to the field where phosphate pollution is notorious but urgent.

  3. Strigolactone regulates anthocyanin accumulation, acid phosphatases production and plant growth under low phosphate condition in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Shinsaku Ito

    Full Text Available Phosphate is an essential macronutrient in plant growth and development; however, the concentration of inorganic phosphate (Pi in soil is often suboptimal for crop performance. Accordingly, plants have developed physiological strategies to adapt to low Pi availability. Here, we report that typical Pi starvation responses in Arabidopsis are partially dependent on the strigolactone (SL signaling pathway. SL treatment induced root hair elongation, anthocyanin accumulation, activation of acid phosphatase, and reduced plant weight, which are characteristic responses to phosphate starvation. Furthermore, the expression profile of SL-response genes correlated with the expression of genes induced by Pi starvation. These results suggest a potential overlap between SL signaling and Pi starvation signaling pathways in plants.

  4. Soil Components Affecting Phosphate Sorption Parameters of Acid Paddy Soils in Guangdong Province

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Soil components affecting phosphate sorption parameters were studied using acid paddy soils derived from basalt, granite, sand-shale and the Pearl River Delta sediments, respectively, in Guangdong Province.For each soil, seven 2.50 g subsamples were equilibrated with 50 mL 0.02 mol L-1 (pH=7.0) of KCl containing 0, 5, 10, 15, 25, 50 and 100 ng P kg-1, respectively, in order to derive P sorption parameters (P sorption maximum, P sorption intensity factor and maximum buffer capacity) by Langmuir isotherm equation. It was shown that the main soil components influencing phosphate sorption maximum (Xm) included soil clay, pH,amorphous iron oxide (Feo) and amorphous aluminum oxide (Alo), with their effects in the order of Alo >Feo > pH > clay. Among these components, pH had a negative effect, and the others had a positive effect.Organic matter (OM) was the only soil component influencing P sorption intensity factor (K). The main components influencing maximum phosphate buffer capacity (MBC) consisted of soil clay, OM, pH, Feo and Alo, with their effects in the order of Alo > OM > pH > Feo > clay. Path analysis indicated that among the components with positive effects on maximum phosphate buffer capacity (MBC), the effect was in the order of Alo > Feo > Clay, while among the components with negative effects, OM > pH. OM played an important role in mobilizing phosphate in acid paddy soils mainly through decreasing the sorption intensity of phosphate by soil particles.

  5. Application of Ground Phosphate Rock to Diminish the Effects of Simulated Acid Rain of Soil Properties

    Institute of Scientific and Technical Information of China (English)

    DONGYUAN-YAN; LIXUE-YUAN

    1992-01-01

    The effects of simulated acid rain retained in soil on the properties of acid soil and its diminishing by application of ground phosphate rock were investigated by using the sorption method.Results show as follows:(1)For yellow brown soil,the effect of simulated acid rain on the properties of soil with a pH value of 5.9 was relatively small,except a great quantity of acid rain deposited on it.(2) for red soil,the effect of simulated acid rain on the properties of soil was significant.With the increase of the amount of acid deposition,the pH value of soil was declined,but the contents of exchangeable H+,Al3+ and Mn2+ and the amount of SO41- retention were increased.(3) Many properties of acid soils could be improved by applying ground phosphate rock.For example,pH value of soils and the amounts of available P and exchangeable Ca2+ and Mg2+ were increased,and the amounts of exchangeable H+ and Al3+ and SO42- retained was reduced.The application of ground posphate rock could effctively diminish the pollution of acid rain to soil.

  6. Screening for phosphate solubilizing bacteria inhabiting the rhizoplane of rice grown in acidic soil in Bangladesh.

    Science.gov (United States)

    Sarkar, Animesh; Islam, Tofazzal; Biswas, Gokul Chandra; Alam, Shohidul; Hossain, Mikail; Talukder, Nur Mohammad

    2012-06-01

    The objectives of the research were to isolate phosphate solubilizing bacteria (PSB) from the rhizoplane of rice (Oryza sativa L.) cv. BRRIdhan 29 cultivated in acidic soils of Tangail in Bangladesh and evaluate their performances in phosphate solubilization in both in vitro and in vivo conditions. A total of 10 bacterial strains were isolated and purified by repeated streak culture on nutrient agar medium. Upon screening, five isolates (OS01, OS03, OS07, OS08 and OS10) showed varying levels of phosphate solubilizing activity in agar plate and broth assays. Among them, the strain OS07 (B1) and two previously isolated PSB strains B2 and B3 were selected for evaluation for their performances in rice alone or in combination of TSP (triple super phosphate: P1) and rock phosphate (P2). Plant height and the number of tillers per plant were significantly increased by all PSB isolates when used in combination with TSP but PSB alone did not influence much on plant height and the number of tillers except B1. The levels of mineral nutrients content in rice plant tissues were generally increased by the application of the PSB in combination with TSP, while the performances of B1 isolate was superior in all aspects to B2 and B3 isolates.

  7. Cement paste column for simultaneous removal of fluoride, phosphate, and nitrate in acidic wastewater.

    Science.gov (United States)

    Park, Joo-Yang; Byun, Hye-Jung; Choi, Won-Ho; Kang, Wan-Hyup

    2008-02-01

    Cement paste, a cured mixture of cement and water, was reported to have considerable capacity for fluoride removal. In this study, heavily mixed fluoric acid wastewater from a semiconductor fabrication plant was applied to a column packed with cement paste granules to evaluate its capacity for the removal of fluoride and three other contaminants, phosphate, nitrate, and sulfate, as well as to investigate the interactions between these contaminants and cement components. The column reduced fluoride to remarkably low levels since fluorite was formed at highly elevated concentrations of calcium and the residual fluoride was further sorbed into the amorphous calcium phosphate that precipitated the entire amount of phosphate until breakthrough. The simultaneous removal of sulfate in the earlier stage was followed by significant removal of nitrate in exchange with the gradual release of sulfate. This behavior was explained by the co-precipitation of sulfate with calcium phosphate or calcium aluminate solids and the subsequent substitution of nitrate for the interlayer sulfate of monosulfate. However, the overall removal capacity of cement paste was reduced due to the high effluent loss of calcium and competition for calcium between fluoride and phosphate.

  8. Triphenyl phosphate-induced developmental toxicity in zebrafish: Potential role of the retinoic acid receptor

    Energy Technology Data Exchange (ETDEWEB)

    Isales, Gregory M.; Hipszer, Rachel A.; Raftery, Tara D. [Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC (United States); Chen, Albert; Stapleton, Heather M. [Division of Environmental Sciences and Policy, Nicholas School of the Environment, Duke University, Durham, NC (United States); Volz, David C., E-mail: volz@mailbox.sc.edu [Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC (United States)

    2015-04-15

    Highlights: • Triphenyl phosphate-induced toxicity in zebrafish embryos is enhanced in the presence of a retinoic acid receptor antagonist. • Triphenyl phosphate uptake or metabolism within zebrafish embryos is not altered in the presence of a retinoic acid receptor antagonist. • Triphenyl phosphate decreases expression of cytochrome P450 26a1 in zebrafish embryos. • Triphenyl phosphate inhibits retinoic acid-induced activation of human retinoic acid receptors. - Abstract: Using zebrafish as a model, we previously reported that developmental exposure to triphenyl phosphate (TPP) – a high-production volume organophosphate-based flame retardant – results in dioxin-like cardiac looping impairments that are independent of the aryl hydrocarbon receptor. Using a pharmacologic approach, the objective of this study was to investigate the potential role of retinoic acid receptor (RAR) – a nuclear receptor that regulates vertebrate heart morphogenesis – in mediating TPP-induced developmental toxicity in zebrafish. We first revealed that static exposure of zebrafish from 5–72 h post-fertilization (hpf) to TPP in the presence of non-toxic concentrations of an RAR antagonist (BMS493) significantly enhanced TPP-induced toxicity (relative to TPP alone), even though identical non-toxic BMS493 concentrations mitigated retinoic acid (RA)-induced toxicity. BMS493-mediated enhancement of TPP toxicity was not a result of differential TPP uptake or metabolism, as internal embryonic doses of TPP and diphenyl phosphate (DPP) – a primary TPP metabolite – were not different in the presence or absence of BMS493. Using real-time PCR, we then quantified the relative change in expression of cytochrome P450 26a1 (cyp26a1) – a major target gene for RA-induced RAR activation in zebrafish – and found that RA and TPP exposure resulted in a ∼5-fold increase and decrease in cyp26a1 expression, respectively, relative to vehicle-exposed embryos. To address whether TPP may

  9. Procedure for the study of acidic calcium phosphate precursor phases in enamel mineral formation.

    Science.gov (United States)

    Siew, C; Gruninger, S E; Chow, L C; Brown, W E

    1992-02-01

    Considerable evidence suggests that an acidic calcium phosphate, such as octacalcium phosphate (OCP) or brushite, is involved as a precursor in enamel and other hard tissue formation. Additionally, there is in vitro evidence suggesting that fluoride accelerates and magnesium inhibits the hydrolysis of OCP to hydroxyapatite (OHAp). As the amount of OCP or brushite in enamel cannot be measured directly in the presence of an excess of hydroxyapatite, a procedure was developed that allows for their indirect in vivo quantification as pyrophosphate. This permits study of the effects of fluoride and magnesium ions on enamel mineral synthesis. Rat incisor calcium phosphate was labeled by intraperitoneal injection of NaH2(32)PO4. The rats were then subjected to various fluoride and magnesium treatments with subcutaneous implanted osmotic pumps. They were then killed at predetermined intervals; the nascent sections of the incisors were collected, cleaned, and pyrolyzed at 500 degrees C for 48 hours to convert acidic calcium phosphates to calcium pyrophosphate; the pyrophosphate was separated from orthophosphate by anion-exchange chromatography; and the resulting fractions were counted by liquid scintillation spectrometry. The activities of the pyro- and orthophosphate fractions were used to calculate the amount of acidic calcium phosphate present in the nascent mineral. The results demonstrated that the percentage of radioactive pyrophosphate in nascent incisors decreased with time, with increasing serum F- concentration, and with decreasing serum magnesium content. The technique described here should prove to be a powerful new tool for studying the effects of various agents on biological mineral formation.

  10. Administering different levels of parenteral phosphate and amino acids did not influence growth in extremely preterm infants

    DEFF Research Database (Denmark)

    Thomsen, Katrine Moe; Beck-Nielsen, Signe Sparre; Lando, Ane

    2015-01-01

    AIM: When a new high amino acid parenteral nutrition (PN) solution was introduced to our hospital, a design error led to decreased phosphate levels. This prompted us to examine the effect of three different PN solutions on plasma phosphate, plasma calcium and weight increases on extremely preterm...

  11. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Cao Xinde [School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Wahbi, Ammar [Soil Science Department, Faculty of Agriculture, University of Aleppo, Aleppo (Syrian Arab Republic); Ma, Lena, E-mail: lqma@ufl.edu [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Li Bing; Yang Yongliang [National Research Center for Geoanalysis, Beijing 100037 (China)

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H{sub 3}PO{sub 4} treatments (PA and PR + PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H{sub 3}PO{sub 4} was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  12. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.

    Science.gov (United States)

    Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  13. Kinetics and thermodynamics of the attack of a phosphate ore by acid solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Antar, K. [Faculty of Science of Tunis, Chemistry Department, Applied Thermodynamics Laboratory, 2092 Tunis El Manar (Tunisia); Jemal, M. [Faculty of Science of Tunis, Chemistry Department, Applied Thermodynamics Laboratory, 2092 Tunis El Manar (Tunisia)], E-mail: jemal@planet.tn

    2008-08-15

    A calorimetric study of the kinetics and thermodynamics of the attack of a phosphate ore from Gafsa region (Tunisia) by phosphoric acid and by a mixture of phosphoric acid and sulfuric acids is undertaken at different temperatures. Two samples of the same ore having different grain size have been used. At 25 deg. C, the dissolution enthalpy in phosphoric acid solution equals -233.6 {+-} 2.2 J/g for both of the samples. Attack by the mixture of acids is strongly dependent on the solid granulometry. Interpretation of the calorimetric results by Avrami model shows the existence of three domains attributed to phosphate ore dissolution/H{sub 2}PO{sub 4}{sup -} neutralisation, hemihydrate (HH) precipitation and hemihydrate/dihydrate (DH) transformation. The attack by the acid mixture was performed at higher temperatures and showed in addition the transitional formation of the anhydrous sulfate (AH) at T {>=} 55 deg. C, which transforms into dihydrate after the HH/DH transformation.

  14. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg-3Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yingwei, E-mail: ywsong@imr.ac.cn; Shan, Dayong; Han, En-Hou

    2013-01-01

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg-3Zn alloy. The Mg-3Zn substrate is first immersed into 0.02 mol L{sup -1} nicotinic acid (NA) solution, named as vitamin B{sub 3}, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: Black-Right-Pointing-Pointer NA/calcium phosphate composite coating is prepared to protect Mg-3Zn alloy implant. Black-Right-Pointing-Pointer Nicotinic acid (vitamin B{sub 3}) is available to obtain a protective bottom film. Black-Right-Pointing-Pointer Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. Black-Right-Pointing-Pointer The composite coating can reduce the biodegradation rate of Mg-3Zn twenty times. Black-Right-Pointing-Pointer The composite coating is biodegraded by the dissolution of flakes into chippings.

  15. Expression of D-myo-inositol-3-phosphate synthase in soybean. Implications for phytic acid biosynthesis.

    Science.gov (United States)

    Hegeman, C E; Good, L L; Grabau, E A

    2001-04-01

    Phytic acid, a phosphorylated derivative of myo-inositol, functions as the major storage form of phosphorus in plant seeds. Myo-inositol phosphates, including phytic acid, play diverse roles in plants as signal transduction molecules, osmoprotectants, and cell wall constituents. D-myo-inositol-3-phosphate synthase (MIPS EC 5.5.1.4) catalyzes the first step in de novo synthesis of myo-inositol. A soybean (Glycine max) MIPS cDNA (GmMIPS1) was isolated by reverse transcriptase-PCR using consensus primers designed from highly conserved regions in other plant MIPS sequences. Southern-blot analysis and database searches indicated the presence of at least four MIPS genes in the soybean genome. Northern-blot and immunoblot analyses indicated higher MIPS expression and accumulation in immature seeds than in other soybean tissues. MIPS was expressed early in the cotyledonary stage of seed development. The GmMIPS1 expression pattern suggested that it encodes a MIPS isoform that functions in seeds to generate D-myo-inositol-3-phosphate as a substrate for phytic acid biosynthesis.

  16. Functionalization of lambda-zirconium phosphate with ethylenediaminetetraacetic acid: Synthesis, characterization and applications

    Indian Academy of Sciences (India)

    Hussein Alhendawi; Ernesto Brunet; Olga Juanes; Salem Idhair; Huda Hammouda; Elena Rodríguez Payán; María De Victoria Rodríguez

    2014-11-01

    A new layered organic-inorganicmaterial based on -Zirconium phosphate (-ZrP) and ethylenediaminetetraacetic acid (H4Y) has been prepared. The thermal analyses, X-ray diffractometry and FT-IR spectrophotometry confirm the introduction of H4Y inside the interlayer gallery of -ZrP. The pristine -ZrP and its new polyaminocarboxylic acid functionalized derivative (-ZrPH2Y) exhibit high potential for the application in the area of hard water treatment, where their Ca2+ uptake capacities are found to be 32.0 and 40.4mg Ca2+ per gram of -solid, respectively.

  17. Dolomite flotation of high magnesium phosphate ores using fatty acid soap collectors

    Science.gov (United States)

    Gu, Zhengxing

    The separation of dolomite from apatite has been recognized as one of the most difficult subjects in mineral processing due to the similarities in their physiochemical properties. In this study, selective surfactants were used with a fatty acid soap collector to improve the flotation performance of separating dolomite from high magnesium phosphate ores. Three surfactants, diethyl phthalate (DP), Tween-80 (TW) and derivative of sulfonate salt (DSS1) were used. Hallimond cell flotation was conducted using pure dolomite sample to determine the effects of various factors including dosages, particle size, Ca2+ ions and slimes on the dolomite flotation recovery. The results showed that the surfactants can significantly improve dolomite flotation performance by increasing collecting ability and tolerating the effect of calcium ions and slime contents. The stirrer-tank cell batch flotation tests were carried out using two natural high magnesium phosphate ore samples containing 3.3% and 1.5% MgO. The test results showed that the surfactant DP could improve dolomite flotation at low dosages, and DSS1 could enhance the separation of dolomite from phosphate by improving both collecting ability and flotation selectivity. When 10% of DSS1 was used with the fatty acid soap as collector, at least 10% more dolomite can be removed with less P2O5 loss. The effectiveness of the surfactant DSS1 in enhancing dolomite flotation was further demonstrated in modified packed column flotation with natural dolomitic phosphate ore sample. The addition of the surfactant DSS1 into fatty acid soap collector could improve its frothability and froth stability, and reduce the bubble size. It has been found that the dolomite flotation performance has a close relationship with the frothability and froth stability of the collector.

  18. Calcium salts of keto-amino acids, a phosphate binder alternative for patients on CAPD.

    Science.gov (United States)

    Macia, M; Coronel, F; Navarro, J F; Gallego, E; Herrero, J A; Méndez, M L; Chahin, J; García, J

    1997-09-01

    Control of hyperphosphoremia is crucial to the prevention of secondary hyperparathyroidism. Calcium salts of keto-amino acids (KAA) were employed as phosphate binders in hemodialysis patients. We wanted to assess the efficacy of these substances as quelating agents in patients under continuous ambulatory peritoneal dialysis (CAPD). Also, as an amino acid supplement, we determined their possible effect on some parameters related to nutritional status. We studied 13 patients (7 M; 6 F) with a mean age of 45.2 +/- 17 years and a mean time on CAPD of 18.4 +/- 11.4 months. None had severe secondary hyperparathyroidism and/or clinically relevant aluminium intoxication. They were not receiving calcitriol and none were using low-calcium peritoneal dialysis fluids. All were under aluminum hydroxide (AlOH3) treatment and 8 patients also received calcium carbonate. These quelating agents were withdrawn and after 21 days (wash-out period) KAA were initiated. We analyzed serum levels of bone metabolism parameters (calcium, phosphate, osteocalcin [OC], intact parathyroid hormone [iPTH], alkaline phosphatase [AP]) and nutritional parameters (total protein, albumin, pre-albumin, transferrin) in four periods: (A) during AlOH3; (B) immediately after the washout period; (C) after 1.5 months; and (D) after 3 months of KAA therapy. In 5 patients serum aluminum level was also measured in periods (A) and (D). The serum phosphate level at period (B) was significantly higher than in other periods. After 3 months of treatment phosphate levels decreased significantly (A = 1.77 +/- 0.3 mmol/l vs D = 1.48 +/- 0.2; p < 0.05). Serum calcium levels increased, while iPTH and OC decreased (p = ns). AP remained stable during the study. All nutritional parameters increased at the end of the study (p = ns). Calcium salts of keto-amino acids showed to be an effective alternative to aluminum-containing phosphate binders. They were well tolerated, without relevant side-effects. These compounds could also

  19. Update on phosphate and charged post-translationally modified amino acid parameters in the GROMOS force field.

    Science.gov (United States)

    Margreitter, Christian; Reif, Maria M; Oostenbrink, Chris

    2017-04-15

    In this study, we propose newly derived parameters for phosphate ions in the context of the GROMOS force field parameter sets. The non-bonded parameters used up to now lead to a hydration free energy, which renders the dihydrogen phosphate ion too hydrophobic when compared to experimentally derived values, making a reparametrization of the phosphate moiety necessary. Phosphate species are of great importance in biomolecular simulations not only because of their crucial role in the backbone of nucleic acids but also as they represent one of the most important types of post-translational modifications to protein side-chains and are an integral part in many lipids. Our re-parametrization of the free dihydrogen phosphate (H 2PO 4-) and three derivatives (methyl phosphate, dimethyl phosphate, and phenyl phosphate) leads, in conjunction with the previously updated charged side-chains in the GROMOS parameter set 54A8, to new nucleic acid backbone parameters and a 54A8 version of the widely used GROMOS protein post-translational modification parameter set. © 2017 Wiley Periodicals, Inc.

  20. Comparison of phosphate estimating methods in the presence of phytic acid for the determination of phytase activity.

    Science.gov (United States)

    Sanikommu, Suma; Pasupuleti, Mukesh; Vadalkonda, Lakshmipathi

    2014-01-01

    Phosphate released from phytic acid can be used as a measure of phytase activity. However, most of the phosphate estimation methods have not examined the interference or interaction of phytic acid in the assay. In this article, we report the kinetics and influence of unreduced phytic acid on phosphate estimation by three of the often-used methods for phytase estimation, the AOAC, Cooper-Gowing, and Fiske-Subbarow methods. Our results show that the AOAC method is most suitable to estimate the phytase activity in the presence of phytate in the medium. In the Fiske and Subbarow method, we noticed that the time factor plays a role in the interference of the phytic acid; especially the readings taken during the second hour of incubation are influenced by the presence of phytic acid. The method of Cooper and Gowing is labor-intensive and is prone to give error values at higher concentrations.

  1. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Octadecanoic acid, ester with 1,2..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as octadecanoic acid,...

  2. Silver di-t-butyl phosphate, a useful reagent in the synthesis of phospholipids. Synthesis of mixed-acid phosphatidic acid and phosphatidyl glycerolphosphate

    NARCIS (Netherlands)

    Bonsen, P.P.M.; Haas, Gerard H. de

    1967-01-01

    The synthesis of silver di-t-butyl phosphate is described. Using this reagent, mixed-acid phosphatidic acid with one unsaturated fatty acid could be prepared by means of a reaction with a 1,2-diacyl glycerol-3-iodohydrin. The blocking groups could be removed easily with dry hydrogen chloride at low

  3. Adsorption of Acid Phosphatase on Minerals and Soil Colloids in Presence of Citrate and Phosphate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aim of this work was to study the influence of phosphate and citrate, which are common inorganic andorganic anions in soils, on the adsorption of acid phosphatase by kaolin, goethite and the colloids separatedfrom yellow-brown soil (YBS) and latosol (LS) in central-south China. The YBS colloid has the major claymineral composition of 1.4 nm mineral, illite and kaolinite while the LS colloid mainly contains kaolinite andoxides. The adsorption isotherm of acid phosphatase on the examined soil colloids and minerals fitted tothe Langmuir model. The amount of enzyme adsorbed in the absence of ligands was in the order of YBScolloid >LS colloid>kaolin≈goethite. In the presence of phosphate or citrate, the amounts of the enzymeadsorbed followed the sequence YBS colloid>kaolin>LS colloid>goethite. The presence of ligands alsodecreased the binding energy between the enzyme and soil colloids or minerals. With the increase of ligandconcentration from 10 mmol L-1 to 400 m mol L-1, different behaviors for the adsorption of enzyme werefound in the colloid and mineral systems studied. A sharp decrease in enzyme adsorption was observed ongoethite while gradual decreases of enzyme adsorption were recorded in the two soil colloid systems. However,no any decrease was found for the amount of enzyme adsorbed on kaolin at higher ligand concentrations.When phosphate or citrate was introduced to the system before the addition of enzyme, the ligands usuallyenhanced the adsorption of enzyme. The results obtained in this study suggested the important role ofkaolinite mineral in the adsorption of enzyme molecules in acidic soils in the presence of various ligands.

  4. Biochar enhances Aspergillus niger rock phosphate solubilization by increasing organic acid production and alleviating fluoride toxicity.

    Science.gov (United States)

    Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo; Costa, Maurício Dutra

    2014-05-01

    During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F(-)) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F(-) adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus niger was examined. Al2O3 adsorbed part of the F(-) released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F(-) while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F(-) measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F(-) per liter can be removed from solution by biochar when added at 3 g liter(-1) to the culture medium. Thus, biochar acted as an F(-) sink during RP solubilization and led to an F(-) concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F(-) and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F(-), the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP.

  5. Comparison of efficacy of the phosphate binders nicotinic acid and sevelamer hydrochloride in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Farrokhlagha Ahmadi

    2012-01-01

    Full Text Available Hyperphosphatemia is a significant risk factor for the development of ectopic calcification and coronary artery diseases in patients on hemodialysis (HD, and must be controlled with the use of phosphate binders. Studies comparing the effects of sevelamer and nicotinic acid, both similar non-calcium and non-aluminum phosphate binders, are not available. In this study, 40 patients on HD with a serum phosphorus level of more than 6 mg/dL were enrolled. After a two week washout period without phosphate binders, the patients were randomly divided into two equal groups (n = 20 and were started on nicotinic acid or sevelamer for a period of four weeks. The dose of nicotinic acid used was 500 mg and that of sevelamer was 1600 mg daily. Blood samples were drawn for the measurement of the total calcium (Ca, phosphorus (P, alkaline phosphatase (ALP, triglyceride (TG, total cholesterol (Chol, high-density lipoprotein (HDL, low-density lipoprotein (LDL, uric acid and parathyroid hormone (PTH. Patients receiving sevelamer showed a significant reduction in serum P level (2.2 ± 0.69 mg/dL; P <0.0001 in comparison with the nicotinic acid group (1.7 ± 1.06 mg/dL; P = 0.004. Reduction in the Ca-P product was significantly different in the two groups; in the sevelamer group, it was 21 ± 7; (P <0.0001 while in the nicotinic acid group, it was 16 ± 11 (P = 0.007. Also, patients on sevelamer showed greater reduction in the mean TG level (38.9 ± 92 mg/dL; P = 0.005. No significant changes were observed in the mean serum Ca, total Chol, HDL, LDL, ALP and iPTH levels in the two study groups. Our short-term study suggests that although nicotinic acid reduced hyperphosphatemia, sevelamer showed higher efficacy in controlling hyperphosphatemia as well as the Ca-P product.

  6. Bulk crystals of L-Histidinium dihydrogen phosphate orthophosphoric acid grown by Sankaranarayanan-Ramasamy method

    Science.gov (United States)

    Ittyachan, Reena; Arunkumar, A.

    2017-01-01

    L-Histidinium dihydrogen phosphate orthophosphoric acid (LHDP) crystal of length 80 mm long and 20 mm diameter has been grown from aqueous solution along c-axis using Sankaranarayanan-Ramasamy method. The unit cell parameters were confirmed by single crystal X-ray diffraction analysis and it belongs to orthorhombic system. The UV-vis-NIR spectrum showed that the grown crystal is transparent in the entire visible region. The lower optical cut-off wavelength for this crystal was observed at 240 nm. Fluorescence studies were carried out in range of 200-700 nm. SHG efficiency was analyzed using Kurtz-Perry powder technique.

  7. Escherichia coli N-Acetylglucosamine-1-Phosphate-Uridyltransferase/Glucosamine-1-Phosphate-Acetyltransferase (GlmU) Inhibitory Activity of Terreic Acid Isolated from Aspergillus terreus.

    Science.gov (United States)

    Sharma, Rashmi; Lambu, Mallikharjuna Rao; Jamwal, Urmila; Rani, Chitra; Chib, Reena; Wazir, Priya; Mukherjee, Debaraj; Chaubey, Asha; Khan, Inshad Ali

    2016-04-01

    Secondary metabolite of Aspergillus terreus, terreic acid, is a reported potent antibacterial that was identified more than 60 years ago, but its cellular target(s) are still unknown. Here we screen its activity against the acetyltransferase domain of a bifunctional enzyme, Escherichia coli N-acetylglucosamine-1-phosphate-uridyltransferase/glucosamine-1-phosphate-acetyltransferase (GlmU). An absorbance-based assay was used to screen terreic acid against the acetyltransferase activity of E. coli GlmU. Terreic acid was found to inhibit the acetyltransferase domain of E. coli GlmU with an IC50 of 44.24 ± 1.85 µM. Mode of inhibition studies revealed that terreic acid was competitive with AcCoA and uncompetitive with GlcN-1-P. It also exhibited concentration-dependent killing of E. coli ATCC 25922 up to 4× minimum inhibitory concentration and inhibited the growth of biofilms generated by E. coli. Characterization of resistant mutants established mutation in the acetyltransferase domain of GlmU. Terreic acid was also found to be metabolically stable in the in vitro incubations with rat liver microsome in the presence of a NADPH regenerating system. The studies reported here suggest that terreic acid is a potent antimicrobial agent and support that E. coli GlmU acetyltransferase is a molecular target of terreic acid, resulting in its antibacterial activity.

  8. Simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewater by zero-valent iron.

    Science.gov (United States)

    Yoshino, Hiroyuki; Tokumura, Masahiro; Kawase, Yoshinori

    2014-01-01

    The zero-valent iron (ZVI) wastewater treatment has been applied to simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewaters. The simultaneous removal occurs by the reactions performed due to the sequential transformation of ZVI under the acidic condition. Fortunately the solution pH of semiconductor acidic wastewaters is low which is effective for the sequential transformation of ZVI. Firstly the reduction of nitrate is taken place by electrons generated by the corrosion of ZVI under acidic conditions. Secondly the ferrous ion generated by the corrosion of ZVI reacts with hydrogen peroxide and generates ·OH radical (Fenton reaction). The Fenton reaction consists of the degradation of hydrogen peroxide and the generation of ferric ion. Finally phosphate precipitates out with iron ions. In the simultaneous removal process, 1.6 mM nitrate, 9.0 mM hydrogen peroxide and 1.0 mM phosphate were completely removed by ZVI within 100, 15 and 15 min, respectively. The synergy among the reactions for the removal of nitrate, hydrogen peroxide and phosphate was found. In the individual pollutant removal experiment, the removal of phosphate by ZVI was limited to 80% after 300 min. Its removal rate was considerably improved in the presence of hydrogen peroxide and the complete removal of phosphate was achieved after 15 min.

  9. CITRIC ACID AS A SET RETARDER FOR CALCIUM ALUMINATE PHOSPHATE CEMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.; BROTHERS, L.E.

    2005-01-01

    Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca{sup 2+} ions from the CAC by carboxylic acid groups within the citric acid. This uptake led to the precipitation of a Ca-complexed carboxylate compound as a set-retarding barrier layer on the CAC grains' surfaces. However, this barrier layer was vulnerable to disintegration by the attack of free Ca{sup 2+} ions from CAC, and also to degradation at elevated temperature, thereby promoting the generation of exothermic energy from acid-base reactions between the CAC and NaP after the barrier was broken. The exothermic reaction energy that was promoted in this way minimized the loss in strength of the citric acid-retarded cement. The phase composition assembled in both retarded and non-retarded cements after autoclaving at 180 C encompassed three reaction products, hydroxyapatite (HOAp), hydrogrossular and boehmite, which are responsible for strengthening the autoclaved cement. The first two reaction products were susceptible to reactions with sulfuric acid and sodium sulfate to form crystalline bassanite scale as the corrosion product. The boehmite phase possessed a great resistance to acid and sulfate. Although the bassanite scales clinging to the cement's surfaces were the major factor governing the loss in weight, they served in protecting the cement from further acid- and sulfate-corrosion until their spallation eventually occurred. Nevertheless, the repetitive processes of HOAp and hydrogrossular {yields} bassanite {yields} spallation played an important role in extending the useful lifetime of CaP cement in a low pH environment at 180 C.

  10. Initial pH of medium affects organic acids production but do not affect phosphate solubilization

    Directory of Open Access Journals (Sweden)

    Leandro M. Marra

    2015-06-01

    Full Text Available The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP. The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici, UFLA03-09 (Acinetobacter sp., UFLA03-10 (Paenibacillus kribbensis, UFLA03-106 (Paenibacillus kribbensis and UFLA03-116 (Paenibacillus sp.. The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO42 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO42 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.

  11. PRINCIPAL COMPONENT ANALYSIS OF FACTORS DETERMINING PHOSPHATE ROCK DISSOLUTION ON ACID SOILS

    Directory of Open Access Journals (Sweden)

    Yusdar Hilman

    2016-10-01

    Full Text Available Many of the agricultural soils in Indonesia are acidic and low in both total and available phosphorus which severely limits their potential for crops production. These problems can be corrected by application of chemical fertilizers. However, these fertilizers are expensive, and cheaper alternatives such as phosphate rock (PR have been considered. Several soil factors may influence the dissolution of PR in soils, including both chemical and physical properties. The study aimed to identify PR dissolution factors and evaluate their relative magnitude. The experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The principal component analysis (PCA was used to characterize acid soils in an incubation system into a number of factors that may affect PR dissolution. Three major factors selected were soil texture, soil acidity, and fertilization. Using the scores of individual factors as independent variables, stepwise regression analysis was performed to derive a PR dissolution function. The factors influencing PR dissolution in order of importance were soil texture, soil acidity, then fertilization. Soil texture factors including clay content and organic C, and soil acidity factor such as P retention capacity interacted positively with P dissolution and promoted PR dissolution effectively. Soil texture factors, such as sand and silt content, soil acidity factors such as pH, and exchangeable Ca decreased PR dissolution.

  12. Mechanistic studies of 3-deoxy-D-manno-octulosonic acid 8-phosphate synthase

    Energy Technology Data Exchange (ETDEWEB)

    Dotson, G.D.; Woodard, R.W. [Univ. of Michigan, Ann Arbor, MI (United States)

    1994-12-01

    The enzyme 3-deOXY-D-manno-octulosonic acid 8-phosphate synthase (KDO 8-P synthase) catalyses the condensation of arabinose 5-phosphate (A 5-P) with phosphoenolpyruvate (PEP) to give the unique eight-carbon acidic sugar 3-deoxy-D-nianno-octulosonic acid 8-phosphate (KDO 8-P) found only in gram-negative bacteria and required for lipid A maturation and cellular growth. The E. coli gene kdsA that encodes KDO 8-P synthase has been amplified by standard PCR methodologies. The synthetic gene, subcloned into the expression vector pT7-7 was used to infect E. coli BL 21 (DE 3). Purification of crude supernatant from this transformant on Q Sepharose yields >200 mg of near-homogeneous KDO 8-P synthase per liter of cell culture. To explore the mechanism of KDO 8-P synthase, we prepared (E)- and (Z)-(3{sup 2}H)PEP, (2-{sup 13}C)PEP, and (2-{sup 13}C,{sup 18}O)PEP chemically from the appropriately labeled 3-bromopyruvates by reaction with trimethylphosphite under Perkow reaction conditions. Our {sup 1}H-NMR analysis of the stereochemistry at C3 of the KDO 8-Ps, obtained by separate incubation of (E)- and (Z)-(3-{sup 2}H)PEP with A 5-P in the presence of KDO 8-P synthase, demonstrated that the reaction is stereospecific with respect to both the C3 of PEP and the C1 carbonyl of A 5-P. (Z)-(3-{sup 2}H)PEP gave predominantly (3S)-(3{sup 2}H)KDO 8-P and (E)-(3-{sup 2}H)PEP gave predominantly (3R)-(3{sup 2}H)KDO-8P, which indicates condensation of the si face of PEP upon the re face of A 5-P-an orientation analogous to that seen with the similar aldehyde Iyase DAH 7-P synthase. The fate of the enolic oxygen of (2-{sup 13}C, {sup 18}O)PEP, during the course of the KDO 8-P synthase-catalyzed reaction as monitored by both {sup 13}C- and {sup 31}P-NMR spectroscopy demonstrated that the inorganic phosphate (Pi) and not the KDO 8-P contained the {sup 18}O.

  13. Synthesis of acylamino acid esters of nucleoside 5'-phosphates and their investigation with PMR and CD spectra.

    Science.gov (United States)

    Azhayev, A V; Popovkina, S V; Tarussova, N B; Kirpichnikov, M P; Florentiev, V L; Krayevsky, A A; Kukhanova, M K; Gottikh, B P

    1977-01-01

    The acylamino acid esters of nucleoside 5'-phosphates are synthesized via condensation of N-(N'-acylaminoacyl) imidazoles with nucleoside 5'-phosphates. The PMR and CD spectra of the esters obtained are studied. The 3'-isomers of the substances under study are observed to have a shift in the conformational N in equilibrium S equilibrium of the carbohydrate moiety in favour of the S-form as compared to the initial nucleosides and their 2'-acyl esters. PMID:909771

  14. Preparation of porous chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles via mineralization

    Institute of Scientific and Technical Information of China (English)

    CHEN ChangJing; DENG Yu; YAN ErYun; HU Yong; JIANG XiQun

    2009-01-01

    In this work,the preparation of chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles (CS-PAA-CaP NP) based on the mineralization of calcium phosphate (CAP) on the surface of chitosan-poly (acrylic acid) nanoparticles (CS-PAA NPs) was reported. CS-PAA-CaP NPs were achieved by directly adding ammonia to the aqueous solution of CS-PAA nanoparticles or by thermal decomposition of urea in the aqueous solution of CS-PAA nanoparticles,resulting in the mineralization of CaP on the surface of CS-PAA NPs. Through these two routes,especially using urea as a pH-regulator,the precipitation of CS-PAA NPs,a common occurrence in basic environment,was avoided. The size,morphology and ingredient of CS-PAA-CaP hybrid nanoparticles were characterized by dynamic light scattering (DLS),transmission electron microscope (TEM),scanning electron microscope (SEM),thermogravimetry analysis (TGA) and X-ray diffractometer (XRD). When urea was used as the pH regulator to facilitate the mineralization during the thermal urea decomposition procedure,regular CS-PAA-CaP hybrid nanoparticles with a porosity-structural CaP shells and 400-600 nm size were obtained. TGA result revealed that the hybrid NPs contained approximately 23% inorganic component,which was consistent with the ratio of starting materials. The XRD spectra of hybrid nanoparticles indicated that dicalcium phosphate (DCP:CaHPO4) crystal was a dominant component of mineralization.The porous structure of the CS-PAA-CaP hybrid NPs might be greatly useful in pharmaceutical and other medical applications.

  15. Crystal structure, vibrational spectra and theoretical studies of L-histidinium dihydrogen phosphate-phosphoric acid

    Science.gov (United States)

    Ahmed, A. Ben; Feki, H.; Abid, Y.; Boughzala, H.; Minot, C.; Mlayah, A.

    2009-02-01

    In this work, we report a combined experimental and theoretical study on molecular structure and vibrational spectra of L-histidinium dihydrogen phosphate-phosphoric acid, with particular emphasize on the correlation between the intermolecular hydrogen bonds and the hyperpolarizability. Single crystal of L-histidinium dihydrogen phosphate-phosphoric acid has been subjected to X-ray diffraction and Raman spectroscopy. The title compound crystallises in the non-centrosymmetric space group P2 1. Raman spectra have been recorded in the frequency range [150-3350 cm -1]. To obtain a more reliable assignment of the Raman and IR spectra, we have calculated the geometry and the frequencies using HF and DFT methods. All the experimental vibrational bands have been discussed and assigned to normal mode or to combinations and overtones on the basis of our calculations. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP and BLYP) are in well agreement with the experimental data. The results of DFT-B3LYP method have shown better fit to experimental ones than HF in evaluating vibrational frequencies. To investigate microscopic second order non-linear optical behaviour of the examined complex, the electric dipole μ, the polarizability α and the hyperpolarizability β were computed using DFT//B3LYP/6-31 G(d) method. According to our calculation, the title compound exhibits non-zero β value revealing microscopic second order NLO behaviour.

  16. Phosphate solubilization and acid phosphatase activity of Serratia sp. isolated from mangrove soil of Mahanadi river delta, Odisha, India

    Directory of Open Access Journals (Sweden)

    B.C. Behera

    2017-06-01

    Full Text Available Phosphorus is an essential element for all life forms. Phosphate solubilizing bacteria are capable of converting phosphate into a bioavailable form through solubilization and mineralization processes. Hence in the present study a phosphate solubilizing bacterium, PSB-37, was isolated from mangrove soil of the Mahanadi river delta using NBRIP-agar and NBRIP-BPB broth containing tricalcium phosphate as the phosphate source. Based on phenotypic and molecular characterization, the strain was identified as Serratia sp. The maximum phosphate solubilizing activity of the strain was determined to be 44.84 μg/ml, accompanied by a decrease in pH of the growth medium from 7.0 to 3.15. During phosphate solubilization, various organic acids, such as malic acid (237 mg/l, lactic acid (599.5 mg/l and acetic acid (5.0 mg/l were also detected in the broth culture through HPLC analysis. Acid phosphatase activity was determined by performing p-nitrophenyl phosphate assay (pNPP of the bacterial broth culture. Optimum acid phosphatase activity was observed at 48 h of incubation (76.808 U/ml, temperature of 45 °C (77.87 U/ml, an agitation rate of 100 rpm (80.40 U/ml, pH 5.0 (80.66 U/ml and with glucose as a original carbon source (80.6 U/ml and ammonium sulphate as a original nitrogen source (80.92 U/ml. Characterization of the partially purified acid phosphatase showed maximum activity at pH 5.0 (85.6 U/ml, temperature of 45 °C (97.87 U/ml and substrate concentration of 2.5 mg/ml (92.7 U/ml. Hence the present phosphate solubilizing and acid phosphatase production activity of the bacterium may have probable use for future industrial, agricultural and biotechnological application.

  17. Nicotinic acid adenine dinucleotide phosphate-mediated calcium signalling in effector T cells regulates autoimmunity of the central nervous system

    Science.gov (United States)

    Cordiglieri, Chiara; Odoardi, Francesca; Zhang, Bo; Nebel, Merle; Kawakami, Naoto; Klinkert, Wolfgang E. F.; Lodygin, Dimtri; Lühder, Fred; Breunig, Esther; Schild, Detlev; Ulaganathan, Vijay Kumar; Dornmair, Klaus; Dammermann, Werner; Potter, Barry V. L.; Guse, Andreas H.

    2010-01-01

    Nicotinic acid adenine dinucleotide phosphate represents a newly identified second messenger in T cells involved in antigen receptor-mediated calcium signalling. Its function in vivo is, however, unknown due to the lack of biocompatible inhibitors. Using a recently developed inhibitor, we explored the role of nicotinic acid adenine dinucleotide phosphate in autoreactive effector T cells during experimental autoimmune encephalomyelitis, the animal model for multiple sclerosis. We provide in vitro and in vivo evidence that calcium signalling controlled by nicotinic acid adenine dinucleotide phosphate is relevant for the pathogenic potential of autoimmune effector T cells. Live two photon imaging and molecular analyses revealed that nicotinic acid adenine dinucleotide phosphate signalling regulates T cell motility and re-activation upon arrival in the nervous tissues. Treatment with the nicotinic acid adenine dinucleotide phosphate inhibitor significantly reduced both the number of stable arrests of effector T cells and their invasive capacity. The levels of pro-inflammatory cytokines interferon-gamma and interleukin-17 were strongly diminished. Consecutively, the clinical symptoms of experimental autoimmune encephalomyelitis were ameliorated. In vitro, antigen-triggered T cell proliferation and cytokine production were evenly suppressed. These inhibitory effects were reversible: after wash-out of the nicotinic acid adenine dinucleotide phosphate antagonist, the effector T cells fully regained their functions. The nicotinic acid derivative BZ194 induced this transient state of non-responsiveness specifically in post-activated effector T cells. Naïve and long-lived memory T cells, which express lower levels of the putative nicotinic acid adenine dinucleotide phosphate receptor, type 1 ryanodine receptor, were not targeted. T cell priming and recall responses in vivo were not reduced. These data indicate that the nicotinic acid adenine dinucleotide phosphate

  18. Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

    Science.gov (United States)

    Kim, Jae Gon

    2017-04-01

    Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

  19. Mechanism of lead immobilization by oxalic acid-activated phosphate rocks

    Institute of Scientific and Technical Information of China (English)

    Guanjie Jiang; Yonghong Liu; Li Huang; Qingling Fu; Youjun Deng; Hongqing Hu

    2012-01-01

    Lead (Pb) chemical fixation is an important environmental aspect for human health.Phosphate rocks (PRs) were utilized as an adsorbent to remove Pb from aqueous solution.Raw PRs and oxalic acid-activated PRs (APRs) were used to investigate the effect of chemical modification on the Pb-binding capacity in the pH range 2.0-5.0.The Pb adsorption rate of all treatments above pH 3.0 reached 90%.The Pb binding on PRs and APRs was pH-independent,except at pH 2.0 in activated treatments.The X-ray diffraction analysis confirmed that the raw PRs formed cerussite after reacting with the Pb solution,whereas the APRs formed pyromorphite.The Fourier Transform Infrared spectroscopy analysis indicated that carbonate (CO2-3) in raw PRs and phosphate (PO3-4 ) groups in APRs played an important role in the Pb-binding process.After adsorption,anomalous block-shaped particles were observed by scanning electron microscopy with energy dispersive spectroscopy.The X-ray photoelectron spectroscopy data further indicated that both chemical and physical reactions occurred during the adsorption process according to the binding energy.Because of lower solubility of pyromorphite compared to cerussite,the APRs are more effective in immobilizing Pb than that of PRs.

  20. Immobilization of heavy metals in sludge using phosphoric acid and monobasic calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    Ping TANG; Yong-chao ZHOU; Zhen-miao XIE

    2013-01-01

    The purpose of this research is to investigate the potential ofpre-treatment with phosphoric acid (PA) and monobasic calcium phosphate (MCP) for the stabilization of heavy metals in sludge and its bottom ash.The tannery sludge samples were collected in Wenzhou,China and heavily contaminated with heavy metals,such as Pb,Cr and so on.The samples were pre-treated with PA or MCP.Then XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb,Cr,Cu,Zn and Cd immobilization in the pre-treated sludge and its bottom ash.The results showed that this treatment effectively immobilized Pb and Cd in the sludge,lightly stabilized the metal Cu,and adversely,enhanced the leachability of Zn.After incineration at 900 ℃,Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration process.However,an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP.

  1. Bioactivity and cytocompatibility of dicalcium phosphate/poly (amino acid) biocomposite with degradability

    Science.gov (United States)

    Zhang, Yunfei; Shan, Wenpeng; Li, Xiangde; Wei, Jie; Li, Hong; Ma, Jian; Yan, Yonggang

    2012-01-01

    A bioactive composite of dicalcium phosphate (DCP) and poly (amino acid) (PAA) was fabricated, and the in vitro bioactivity, degradability, and cellular responses to the DCP/PAA composite (DPC) were investigated as compared to PAA. Apatite formation on DPC surfaces occurred after immersion into simulated body fluid (SBF) for 7 days, but not on the surface of PAA. The weight loss ratio of DPC could reach 18.6 ± 0.3 wt% after soaking into phosphate buffered saline (PBS) for 2 months, which was higher than PAA (11.0 ± 0.2 wt%). Cell attachment and proliferation of MG-63 cells on DPC was obviously higher than on PAA. Moreover, the cells spread and formed confluent layer on the DPC surfaces. The alkaline phosphatase activity (ALP) of the cells on DPC was significantly greater than PAA at day 5 and day 7. The results suggested that introducing DCP into PAA makes the composite bioactive and more degradable, and meanwhile enhances osteoblast-like cells attach, proliferation and osteogenic differentiation.

  2. Bioactivity and cytocompatibility of dicalcium phosphate/poly (amino acid) biocomposite with degradability

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yunfei [College of Chemistry, Sichuan University, Chengdu 610064 (China); Shan Wenpeng; Li Xiangde [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Wei Jie, E-mail: biomater2006@yahoo.com.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Li Hong [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Ma Jian [Hospital of Stomatology, Tongji University, Shanghai 200072 (China); Yan Yonggang, E-mail: yan_yonggang@vip.163.com [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

    2012-01-15

    A bioactive composite of dicalcium phosphate (DCP) and poly (amino acid) (PAA) was fabricated, and the in vitro bioactivity, degradability, and cellular responses to the DCP/PAA composite (DPC) were investigated as compared to PAA. Apatite formation on DPC surfaces occurred after immersion into simulated body fluid (SBF) for 7 days, but not on the surface of PAA. The weight loss ratio of DPC could reach 18.6 {+-} 0.3 wt% after soaking into phosphate buffered saline (PBS) for 2 months, which was higher than PAA (11.0 {+-} 0.2 wt%). Cell attachment and proliferation of MG-63 cells on DPC was obviously higher than on PAA. Moreover, the cells spread and formed confluent layer on the DPC surfaces. The alkaline phosphatase activity (ALP) of the cells on DPC was significantly greater than PAA at day 5 and day 7. The results suggested that introducing DCP into PAA makes the composite bioactive and more degradable, and meanwhile enhances osteoblast-like cells attach, proliferation and osteogenic differentiation.

  3. Abscisic acid effects on activity and expression of barley (Hordeum vulgare) plastidial glucose-6-phosphate dehydrogenase.

    Science.gov (United States)

    Cardi, Manuela; Chibani, Kamel; Cafasso, Donata; Rouhier, Nicolas; Jacquot, Jean-Pierre; Esposito, Sergio

    2011-07-01

    Total glucose-6-phosphate dehydrogenase (G6PDH) activity, protein abundance, and transcript levels of G6PDH isoforms were measured in response to exogenous abscisic acid (ABA) supply to barley (Hordeum vulgare cv Nure) hydroponic culture. Total G6PDH activity increased by 50% in roots treated for 12 h with exogenous 0.1 mM ABA. In roots, a considerable increase (35%) in plastidial P2-G6PDH transcript levels was observed during the first 3 h of ABA treatment. Similar protein variations were observed in immunoblotting analyses. In leaves, a 2-fold increase in total G6PDH activity was observed after ABA treatment, probably related to an increase in the mRNA level (increased by 50%) and amount of protein (increased by 85%) of P2-G6PDH. Together these results suggest that the plastidial P2-isoform plays an important role in ABA-treated barley plants.

  4. Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas

    OpenAIRE

    Vyas Pratibha; Gulati Arvind

    2009-01-01

    Abstract Background Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acid...

  5. Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate.

    Science.gov (United States)

    Hiemstra, Tjisse; Mia, Shamim; Duhaut, Pierre-Benoît; Molleman, Bastiaan

    2013-08-20

    Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application of biochar, potentially creating Darks Earths or Terra Preta soils. A surface complexation approach has been developed that aims to describe the competitive behavior of natural organic matter (NOM) in soil as well as model systems. Modeling points unexpectedly to a strong change of the molecular conformation of humic acid (HA) with a predominant adsorption in the Stern layer domain at low NOM loading. In soil, mineral oxide surfaces remain efficiently loaded by mineral-protected organic carbon (OC), equivalent with a layer thickness of ≥ ~0.5 nm that represents at least 0.1-1.0% OC, while surface-associated OC may be even three times higher. In natural systems, surface complexation modeling should account for this pervasive NOM coverage. With our charge distribution model for NOM (NOM-CD), the pH-dependent oxyanion competition of the organo-mineral oxide fraction can be described. For pyrogenic HA, a more than 10-fold increase in dissolved phosphate is predicted at long-term applications of biochar or black carbon.

  6. Proton exchange nanocomposite membranes based on 3-glycidoxypropyltrimethoxysilane, silicotungstic acid and {alpha}-zirconium phosphate hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong-il; Nagai, Masayuki [Advanced Research Center for Energy and Environment, Musashi Institute of Technology, 1-28-1 Tamazutsumi, Tokyo 158-8557 Setagaya (Japan)

    2001-12-01

    Novel fast proton-conducting GPTS-STA-SiO{sub 2} and GPTS-STA-ZrP composites were successfully fabricated. The polymer matrix obtained through hydrolysis and condensation reaction of 3-glycidoxypropyltrimethoxysilane (GPTS) showed apparent proton conduction at high relative humidity with conductivity from 1.0x10{sup -7} to 3.6x10{sup -6} S/cm, although no proton donor was incorporated. The proton conductivities of the fabricated composites were high, and increased up to 1.9x10{sup -2} S/cm by addition of silicotungstic acid (STA). By incorporating {alpha}-zirconium phosphate (ZrP) into the GPTS-STA polymer matrix, the composite showed increased conductivity at low temperature (80C), indicating weak dependence on humidity by molecular water in ZrP. The high proton conductivity of the composites is due to the proton conducting path through the GPTS-derived 'pseudo-polyethylene oxide (pseudo-PEO)' networks, which also contains a trapped solid acid (silicotungstic acid) as a proton donor.

  7. Glycerol-3-phosphate dehydrogenase 1 deficiency induces compensatory amino acid metabolism during fasting in mice.

    Science.gov (United States)

    Sato, Tomoki; Yoshida, Yuma; Morita, Akihito; Mori, Nobuko; Miura, Shinji

    2016-11-01

    Glucose is used as an energy source in many organs and obtained from dietary carbohydrates. However, when the external energy supply is interrupted, e.g., during fasting, carbohydrates preserved in the liver and glycogenic precursors derived from other organs are used to maintain blood glucose levels. Glycerol and glycogenic amino acids derived from adipocytes and skeletal muscles are utilized as glycogenic precursors. Glycerol-3-phosphate dehydrogenase 1 (GPD1), an NAD(+)/NADH-dependent enzyme present in the cytosol, catalyzes the reversible conversion of glycerol-3-phosphate (G3P) to dihydroxyacetone phosphate (DHAP). Since G3P is one of the substrates utilized for gluconeogenesis in the liver, the conversion of G3P to DHAP by GPD1 is essential for maintaining blood glucose levels during fasting. We focused on GPD1 and examined its roles in gluconeogenesis during fasting. Using GPD1 null model BALB/cHeA mice (HeA mice), we measured gluconeogenesis from glycerol and the change of blood glucose levels under fasting conditions. We also measured gene expression related to gluconeogenesis in the liver and protein metabolism in skeletal muscle. BALB/cBy mice (By mice) were used as a control. The blood glucose levels in the HeA mice were lower than that in the By mice after glycerol administration. Although lack of GPD1 inhibited gluconeogenesis from glycerol, blood glucose levels in the HeA mice after 1-4h of fasting were significantly higher than that in the By mice. Muscle protein synthesis in HeA mice was significantly lower than that in the By mice. Moreover, blood alanine levels and usage of alanine for gluconeogenesis in the liver were significantly higher in the HeA mice than that in the By mice. Although these data indicate that a lack of GPD1 inhibits gluconeogenesis from glycerol, chronic GPD1 deficiency may induce an adaptation that enhances gluconeogenesis from glycogenic amino acids. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Maillard Reactions of Ribose 5‐Phosphate and Amino Acids

    National Research Council Canada - National Science Library

    SANDWICK, ROGER; JOHANSON, MATTHEW; BREUER, ELIZABETH

    2005-01-01

    A bstract : An important metabolite in nucleotide synthesis, ribose 5‐phosphate (R5P) undergoes Maillard reactions at a rate significantly faster than most common sugars and sugar phosphates of its type...

  9. Application of acid-activated Bauxsol for wastewater treatment with high phosphate concentration: Characterization, adsorption optimization, and desorption behaviors.

    Science.gov (United States)

    Ye, Jie; Cong, Xiangna; Zhang, Panyue; Zeng, Guangming; Hoffmann, Erhard; Liu, Yang; Wu, Yan; Zhang, Haibo; Fang, Wei; Hahn, Hermann H

    2016-02-01

    Acid-activated Bauxsol was applied to treat wastewater with high phosphate concentration in a batch adsorption system in this paper. The effect of acid activation on the change of Bauxsol structure was systematically investigated. The mineralogical inhomogeneity and intensity of Bauxsol decreased after acid activation, and FeCl3·2H2O and Al(OH)3 became the dominant phases of acid-activated Bauxsol adsorption. Moreover, the BET surface area and total pore volume of Bauxsol increased after acid activation. Interaction of initial solution pH and adsorption temperature on phosphate adsorption onto acid-activated Bauxsol was investigated by using response surface methodology with central composite design. The maximum phosphate adsorption capacity of 192.94 mg g(-1) was achieved with an initial solution pH of 4.19 and an adsorption temperature of 52.18 °C, which increased by 7.61 times compared with that of Bauxsol (22.40 mg g(-1)), and was higher than other adsorbents. Furthermore, the desorption studies demonstrated that the acid-activated Bauxsol was successfully regenerated with 0.5 mol L(-1) HCl solution. The adsorption capacity and desorption efficiency of acid-activated Bauxsol maintained at 80.48% and 93.02% in the fifth adsorption-desorption cycle, respectively, suggesting that the acid-activated Bauxsol could be repeatedly used in wastewater treatment with high phosphate concentration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. rhBMP-2 release from injectable poly(DL-lactic-co-glycolic acid)/calcium-phosphate cement composites.

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2003-01-01

    BACKGROUND: In bone tissue engineering, poly(DL-lactic-co-glycolic acid) (PLGA) microparticles are frequently used as a delivery vehicle for bioactive molecules. Calcium phosphate cement is an injectable, osteoconductive, and degradable bone cement that sets in situ. The objective of this study was

  11. Effect of poly(aspartic acid) on calcium phosphate removal from stainless steel tubing under turbulent flow conditions

    Science.gov (United States)

    Littlejohn, Felicia

    Calcium phosphate deposition causes cleaning problems in a number of situations including water treatment, dairy processing, and dental applications. This problem is exacerbated by the limited choices of cleaning chemicals that meet environmental regulations. To promote the development of biodegradable, non-toxic alternatives, this research examines the removal of calcium phosphate deposits consisting of brushite (dicalcium phosphate dihydrate; DCPD) and a mixture of hydroxyapatite (HAP) and DCPD from stainless steel in the presence of poly(aspartic acid) and its sodium salt (PASP). The effects of solvent pH, PASP concentration, and flow rate on the calcium phosphate removal rates are measured from stainless steel tubing under turbulent flow conditions using a solid scintillation detection technique. A mechanistic evaluation of the cleaning data in the absence of PASP indicates that DCPD removal is dominated by shear while HAP/DCPD deposit removal is limited by a combination of mass transfer and interfacial processes. Although the removal mechanisms differ, the results conclusively show that PASP promotes calcium phosphate removal under conditions that favor calcium sequestration in both cases. An in-depth study of DCPD removal in the presence of PASP reveals that this additive is most effective under conditions where calcium sequestration and phosphate protonation occur simultaneously.

  12. Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bao-hua; WU De-yi; WANG Chong; HE Sheng-bing; ZHANG Zhen-jia; KONG Hai-nan

    2007-01-01

    Zeolite synthesized from fly ash (ZFA) without modification is not efficient for the purification of NH4+ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 (≥0.9 mol/L) resulted in a limited maximum phosphate immobilization capacity (PIC). It was concluded that through a previous mild acid treatment (e.g. 0.01 mol/L of H2SO4), ZFA can be used in the simultaneous removal of NH4+ and P at low concentrations simulating real effluent.

  13. Final report of the safety assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as used in cosmetics.

    Science.gov (United States)

    Elmore, Amy R

    2005-01-01

    L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or microscopic pathological effects were

  14. Redundant Systems of Phosphatidic Acid Biosynthesis via Acylation of Glycerol-3-Phosphate or Dihydroxyacetone Phosphate in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Athenstaedt, Karin; Weys, Sabine; Paltauf, Fritz; Daum, Günther

    1999-01-01

    In the yeast Saccharomyces cerevisiae lipid particles harbor two acyltransferases, Gat1p and Slc1p, which catalyze subsequent steps of acylation required for the formation of phosphatidic acid. Both enzymes are also components of the endoplasmic reticulum, but this compartment contains additional acyltransferase(s) involved in the biosynthesis of phosphatidic acid (K. Athenstaedt and G. Daum, J. Bacteriol. 179:7611–7616, 1997). Using the gat1 mutant strain TTA1, we show here that Gat1p presen...

  15. Synthesis of lithium iron phosphate/carbon microspheres by using polyacrylic acid coated iron phosphate nanoparticles derived from iron(III) acrylate.

    Science.gov (United States)

    Xu, Dongwei; He, Yan-Bing; Chu, Xiaodong; Ding, Zhaojun; Li, Baohua; He, Jianfu; Du, Hongda; Qin, Xianying; Kang, Feiyu

    2015-03-01

    Lithium iron phosphate/carbon (LiFePO4 /C) microspheres with high rate and cycling performance are synthesized from iron phosphate/polyacrylic acid (FePO4 /PAA) nanoparticles. Iron(III) acrylate is used as a precursor for both the iron and carbon sources. FePO4 nanoparticles are first produced by a coprecipitation reaction. The byproduct, acrylic acid ions, is polymerized in situ to form a uniform PAA layer on the surface of the FePO4 nanoparticles. The as-prepared LiFePO4 /C microspheres are composed of primary nanoparticles with sizes of 40-50 nm. The nanoparticles are fully coated with a thin, uniform carbon layer derived from the decomposition of the PAA layer. The uniform carbon-coating layer cooperates with interstitial and boundary carbon derived from sucrose successfully to construct an excellent interconnecting conductive network in the microspheres. As a result of the unique structure, the as-prepared LiFePO4 /C microspheres display both high electronic and ionic conductivities, which contribute to their high rate performance (162.9 mAh g(-1) at 0.1C and 126.1 mAh g(-1) at 5C) and excellent cycling stability (97.1% of capacity retention after 500 cycles at 5C/5C).

  16. Tris(2-butoxyethyl)phosphate and triethyl phosphate alter embryonic development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations in chicken embryos

    Energy Technology Data Exchange (ETDEWEB)

    Egloff, Caroline [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Crump, Doug, E-mail: doug.crump@ec.gc.ca [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Porter, Emily; Williams, Kim L.; Letcher, Robert J.; Gauthier, Lewis T. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Kennedy, Sean W. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5 (Canada)

    2014-09-15

    The organophosphate flame retardants tris(2-butoxyethyl) phosphate (TBOEP) and triethyl phosphate (TEP) are used in a wide range of applications to suppress or delay the ignition and spread of fire. Both compounds have been detected in the environment and TBOEP was recently measured in free-living avian species. In this study, TBOEP and TEP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 45,400 ng/g and 0 to 241,500 ng/g egg, respectively. Pipping success, development, hepatic mRNA expression of 9 target genes, thyroid hormone levels, and circulating bile acid concentrations were determined. Exposure to the highest doses of TBOEP and TEP resulted in negligible detection of the parent compounds in embryonic contents at pipping indicating their complete metabolic degradation. TBOEP exposure had limited effects on chicken embryos, with the exception of hepatic CYP3A37 mRNA induction. TEP exposure decreased pipping success to 68%, altered growth, increased liver somatic index (LSI) and plasma bile acids, and modulated genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Plasma thyroxine levels were decreased at all TEP doses, including an environmentally-relevant concentration (8 ng/g), and gallbladder hypotrophy was evident at ≥ 43,200 ng/g. Tarsus length and circulating thyroxine concentration emerged as potential phenotypic anchors for the modulation of transthyretin mRNA. The increase in plasma bile acids and LSI, gallbladder hypotrophy, and discoloration of liver tissue represented potential phenotypic outcomes associated with modulation of hepatic genes involved with xenobiotic and lipid metabolism. - Highlights: • TBOEP is not embryolethal to chicken embryos. • TEP affected embryonic viability, morphometric endpoints, and thyroid hormone levels. • TEP altered mRNA levels of xenobiotic and lipid metabolism genes. • TEP increased plasma bile acids and caused gallbladder hypotrophy

  17. Fabrication of novel poly(lactic acid)/amorphous magnesium phosphate bionanocomposite fibers for tissue engineering applications via electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huan, E-mail: Huan.Zhou@Rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Nabiyouni, Maryam [Department of Bioengineering, The University of Toledo, Toledo, OH (United States); Lin, Boren [Department of Biological Sciences, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Department of Surgery (Dentistry), The University of Toledo, Toledo, OH (United States)

    2013-05-01

    Fibrous bionanocomposites consisting of amorphous magnesium phosphate (AMP) nanospheres and polylactic acid (PLA) were fabricated by electrospinning. There are two important signatures of this paper. First, AMP, as an alternative to well-known calcium phosphate (CaP) materials, is added to PLA as the second phase. To the best of our knowledge, it is the first attempt to fabricate magnesium phosphate (MgP)/biopolymer composite. This is made possible by our previously reported research on the successful synthesis of AMP nanospheres via microwave processing. Second, the sustained release of magnesium and phosphate ions from PLA matrix can stimulate a series of cell responses. The structure of the composites and their bone-like apatite-forming abilities in simulated body fluid (SBF) were examined. Additionally, the effects on the proliferation and differentiation of preosteoblast cells were evaluated by performing in vitro cell culture and monitoring markers such as Osteocalcin (OCN), Osteopontin (OPN), Alkaline phosphatase (ALP) and Collagen type-I (Col I) using real-time polymerase chain reaction (PCR). For better dispersion of AMP in the fibers, a surfactant, 12-hydroxysteric acid (HSA), as previously reported in the literature, was used. However, HSA significantly inhibited the proliferation and differentiation of preosteoblast cells, indicating the potential risk in using HSA in the combination of AMP or MgP in tissue engineering applications. - Highlights: ► Amorphous magnesium phosphate (AMP) nanospheres was synthesized. ► AMP/poly lactic acid (PLA) matrix was fabricated via electrospinning. ► AMP was found to be beneficial to MC3T3 preosteoblast cells proliferation. ► Surfactant 12-hydroxysteric acid (HSA) was toxic to preosteoblast cells.

  18. Repression of mineral phosphate solubilizing phenotype in the presence of weak organic acids in plant growth promoting fluorescent pseudomonads.

    Science.gov (United States)

    Patel, Divya K; Murawala, Prayag; Archana, G; Kumar, G Naresh

    2011-02-01

    Two phosphate solubilizing bacteria (PSB), M3 and SP1, were obtained from the rhizosphere of mungbean and sweet potato, respectively and identified as strains of Pseudomonas aeruginosa. Their rock phosphate (RP) solubilizing abilities were found to be due to secretion high amount of gluconic acid. In the presence of malate and succinate, individually and as mixture, the P solubilizing ability of both the strains was considerably reduced. This was correlated with a nearly 80% decrease in the activity of the glucose dehydrogenase (GDH) but not gluconate dehydrogenase (GAD) in both the isolates. Thus, GDH enzyme, catalyzing the periplasmic production of gluconic acid, is under reverse catabolite repression control by organic acids in P. aeruginosa M3 and SP1. This is of relevance in rhizospheric conditions and is a new explanation for the lack of field efficacy of such PSB.

  19. Radiological, chemical and morphological characterizations of phosphate rock and phosphogypsum from phosphoric acid factories in SW Spain

    Energy Technology Data Exchange (ETDEWEB)

    Renteria-Villalobos, Marusia, E-mail: marusia@us.es [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Departamento de Fisica Aplicada, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Advanced Materials Research Center (CIMAV), Miguel de Cervantes 120, 31109 Chihuahua (Mexico); Vioque, Ignacio, E-mail: ivioque@us.es [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Departamento de Fisica Aplicada, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Mantero, Juan, E-mail: manter@us.es [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Departamento de Fisica Aplicada, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Manjon, Guillermo, E-mail: manjon@us.es [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Departamento de Fisica Aplicada, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2010-09-15

    In this work, radiological, chemical, and also morphological characterization was performed in phosphate rock and phosphogypsum samples, in order to understand the behavior of toxic elements. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), gamma spectrometry and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Our results show that the phosphate rock was mainly composed of fluorapatite, calcite, perovskite, quartz, magnetite, pyrite and kaolinite, whereas phosphogypsum only exhibited dihydrated calcium sulfate. The activity concentration of U-series radioisotopes in phosphate rock was around 1640 Bq/kg. {sup 226}Ra and {sup 210}Pb tend to be distributed into phosphogypsum by up to 80%, whereas the fraction of U-isotopes is 10%. The most abundant trace elements in phosphate rock were Sr, Cr, V, Zn, Y, Ni and Ba. Some elements, such as Ba, Cd, Cu, La, Pb, Se, Sr, Th and Y, were enriched in the phosphogypsum. This enrichment may be attributed to an additional input associated to the sulfuric acid used for the phosphoric acid production. Furthermore, results from SEM-EDX demonstrated that toxic elements are not distributed homogeneously into phosphogypsum. Most of these elements are concentrated in particles <20 {mu}m of high porosity, and could be easily mobilized by leaching and/or erosion.

  20. Radiological, chemical and morphological characterizations of phosphate rock and phosphogypsum from phosphoric acid factories in SW Spain.

    Science.gov (United States)

    Rentería-Villalobos, Marusia; Vioque, Ignacio; Mantero, Juan; Manjón, Guillermo

    2010-09-15

    In this work, radiological, chemical, and also morphological characterization was performed in phosphate rock and phosphogypsum samples, in order to understand the behavior of toxic elements. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), gamma spectrometry and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Our results show that the phosphate rock was mainly composed of fluorapatite, calcite, perovskite, quartz, magnetite, pyrite and kaolinite, whereas phosphogypsum only exhibited dihydrated calcium sulfate. The activity concentration of U-series radioisotopes in phosphate rock was around 1640 Bq/kg. (226)Ra and (210)Pb tend to be distributed into phosphogypsum by up to 80%, whereas the fraction of U-isotopes is 10%. The most abundant trace elements in phosphate rock were Sr, Cr, V, Zn, Y, Ni and Ba. Some elements, such as Ba, Cd, Cu, La, Pb, Se, Sr, Th and Y, were enriched in the phosphogypsum. This enrichment may be attributed to an additional input associated to the sulfuric acid used for the phosphoric acid production. Furthermore, results from SEM-EDX demonstrated that toxic elements are not distributed homogeneously into phosphogypsum. Most of these elements are concentrated in particles <20 microm of high porosity, and could be easily mobilized by leaching and/or erosion.

  1. Thallium extraction from hydrochloric acid media into a deep eutectic solvent using bis(2-ethylhexyl) phosphate

    Science.gov (United States)

    Tran, Kate; Volia, Merinda; Tereshatov, Evgeny; Folden, Charles, III

    2016-09-01

    The chemical properties of superheavy elements are relatively unknown due to their short half-lives and difficulty of production. In preparation for a future experiment to study the chemical properties of element 113, separation techniques have been used to study the behavior of its homologs, In and Tl. Previous work studied the liquid-liquid extraction of radioactive 201Tl (t1 / 2 = 3 . 04 d) from various concentrations of HCl into a mixture of menthol and lauric acid that formed a so-called deep eutectic solvent (DES). This work focuses on the effects of adding an extraction agent, bis(2-ethylhexyl) phosphate (HDEHP), to the DES on the efficiency of thallium extraction. The extraction of Tl(I) was generally poor, both with and without HDEHP added. In contrast, 111In (t1 / 2 = 2 . 80 d) showed significant extraction using HDEHP added to the same DES. This difference in behavior could potentially be exploited in a future experiment on the chemistry of element 113. National Science Foundation.

  2. Enhanced Biodegradability, Lubricity and Corrosiveness of Lubricating Oil by Oleic Acid Diethanolamide Phosphate

    Directory of Open Access Journals (Sweden)

    Fang Jianhua

    2012-09-01

    Full Text Available Impacts of oleic acid diethanolamide phosphate (abbreviated as ODAP as an additive on biodegradability, anti-wear capacity, friction-reducing ability and corrosiveness of an unreadily biodegradable HVI 350 mineral lubricating oil was studied. The biodegradabilities of neat lubricating oil and its formulations with ODAP were evaluated on a biodegradation tester. Furthermore, the anti-wear and friction-reducing abilities and the corrosiveness of neat oil and the formulated oils were determined on a four-ball tribotester and a copper strip corrosion tester, respectively. The results indicated that ODAP markedly enhanced biodegradability as well as anti-wear and friction-reducing abilities of the lubricating oil. On the other hand, excellent color ratings of copper strips for both neat oil and the ODAP-doped oil were obtained in the corrosion tests, demonstrating that the corrosiveness of neat oil and the doped oil was negligible, although the latter seemed to provide slightly better anti-corrosion ability.

  3. Photoactive layer-by-layer films of cellulose phosphate and titanium dioxide containing phosphotungstic acid

    Science.gov (United States)

    Ullah, Sajjad; Acuña, José Javier Sáez; Pasa, André Avelino; Bilmes, Sara A.; Vela, Maria Elena; Benitez, Guillermo; Rodrigues-Filho, Ubirajara Pereira

    2013-07-01

    A versatile layer-by-layer (LbL) procedure for the preparation of highly dispersed, adherent and porous multilayer films of TiO2 nanoparticles (NPs) and phosphotungstic acid (HPW) on a variety of substrates at room temperature was developed based on the use of cellulose phosphate (CP) as an efficient and non-conventional polyelectrolyte. UV/vis absorption spectroscopy confirmed the linear and regular growth of the films with the number of immersion cycles and a strong adsorption ability of CP towards TiO2 NPs. FTIR spectroscopy showed that HPW binds to the surface of TiO2 through the oxygen atom at the corner of the Keggin structure. XPS results showed that the interaction between TiO2 and CP is through Ti-O-P linkage. A model is proposed for the TiO2-HPW interaction based on XPS and FTIR results. FEG/SEM study of the surface morphology revealed a porous film structure with a homogenous distribution of the TiO2 NPs induced by CP. HRTEM studies showed that the resulting composite films consist of crystalline anatase and rutile phases and poly-nano-crystalline HPW with a semi-crystalline TiO2-HPW interface. These CP/TiO2 and CP/TiO2/HPW LbL films showed good photoactivity against both saturated and unsaturated species, for instance, stearic acid (SA), crystal violet (CV) and methylene blue (MB) under UV irradiation. The CP/HPW films formed on bacterial cellulose (BC) showed good photochromic response which is enhanced in presence of TiO2 due to an interfacial electron transfer from TiO2 to HPW. This simple and environmentally safe method can be used to form coatings on a variety of surfaces with photoactive TiO2 and TiO2/HPW films.

  4. Designable architectures on nanoparticle surfaces: zirconium phosphate nanoplatelets as a platform for tetravalent metal and phosphonic acid assemblies.

    Science.gov (United States)

    Mosby, Brian M; Goloby, Mark; Díaz, Agustín; Bakhmutov, Vladimir; Clearfield, Abraham

    2014-03-11

    Surface-functionalized zirconium phosphate (ZrP) nanoparticles were synthesized using a combination of ion exchange and self-assembly techniques. The surface of ZrP was used as a platform to deposit tetravalent metal ions by direct ion exchange with the protons of the surface phosphate groups. Subsequently, phosphonic acids were attached to the metal ion layer, effectively functionalizing the ZrP nanoparticles. Use of axially oriented bisphosphonic acids led to the ability to build layer-by-layer assemblies from the nanoparticle surface. Varying the metal ion and ligand used allowed designable architectures to be synthesized on the nanoparticle surface. X-ray powder diffraction, XPS, electron microprobe, solid-state NMR, FTIR, and TGA were used to characterize the synthesized materials.

  5. A study of organic acid production in contrasts between two phosphate solubilizing fungi: Penicillium oxalicum and Aspergillus niger

    Science.gov (United States)

    Li, Zhen; Bai, Tongshuo; Dai, Letian; Wang, Fuwei; Tao, Jinjin; Meng, Shiting; Hu, Yunxiao; Wang, Shimei; Hu, Shuijin

    2016-04-01

    Phosphate solubilizing fungi (PSF) have huge potentials in enhancing release of phosphorus from fertilizer. Two PSF (NJDL-03 and NJDL-12) were isolated and identified as Penicillium oxalicum and Aspergillus niger respectively in this study. The quantification and identification of organic acids were performed by HPLC. Total concentrations of organic acids secreted by NJDL-03 and NJDL-12 are ~4000 and ~10,000 mg/L with pH values of 3.6 and 2.4 respectively after five-days culture. Oxalic acid dominates acidity in the medium due to its high concentration and high acidity constant. The two fungi were also cultured for five days with the initial pH values of the medium varied from 6.5 to 1.5. The biomass reached the maximum when the initial pH values are 4.5 for NJDL-03 and 2.5 for NJDL-12. The organic acids for NJDL-12 reach the maximum at the initial pH = 5.5. However, the acids by NJDL-03 continue to decrease and proliferation of the fungus terminates at pH = 2.5. The citric acid production increases significantly for NJDL-12 at acidic environment, whereas formic and oxalic acids decrease sharply for both two fungi. This study shows that NJDL-12 has higher ability in acid production and has stronger adaptability to acidic environment than NJDL-03.

  6. The effect of nedocromil sodium, sodium cromoglycate and codeine phosphate on citric acid-induced cough in dogs.

    Science.gov (United States)

    Jackson, D. M.

    1988-01-01

    1. The effects of nedocromil sodium, sodium cromoglycate and codeine phosphate on citric acid-induced cough have been studied in conscious tracheostomised dogs. 2. Nedocromil sodium (approximately 15 mg given as an aerosol) and codeine phosphate (5 mg kg-1, i.v.) significantly increased the time to the first cough when dogs were challenged with citric acid aerosol. The mean number of coughs in the initial period of coughing fell after treatment of dogs with nedocromil sodium or with codeine phosphate, but this reduction in mean cough number was not statistically significant. 3. Neither sodium cromoglycate (approximately 15 mg given as an aerosol) nor saline had significant effect on a citric acid challenge. 4. It is concluded that nedocromil sodium, but not sodium cromoglycate, possesses an anti-tussive action that may result from inhibition of sensory nerve activity in the lung. Nedocromil sodium may prove useful in the treatment of unproductive cough in situations where the use of a centrally-acting antitussive is undesirable. PMID:2836011

  7. Valproic acid enforces the priming effect of sphingosine-1 phosphate on human mesenchymal stem cells.

    Science.gov (United States)

    Lim, Jisun; Lee, Seungun; Ju, Hyein; Kim, Yonghwan; Heo, Jinbeom; Lee, Hye-Yeon; Choi, Kyung-Chul; Son, Jaekyoung; Oh, Yeon-Mok; Kim, In-Gyu; Shin, Dong-Myung

    2017-09-01

    Engraftment and homing of mesenchymal stem cells (MSCs) are modulated by priming factors including the bioactive lipid sphingosine-1-phosphate (S1P), by stimulating CXCR4 receptor signaling cascades. However, limited in vivo efficacy and the remaining priming molecules prior to administration of MSCs can provoke concerns regarding the efficiency and safety of MSC priming. Here, we showed that valproic acid (VPA), a histone deacetylase inhibitor, enforced the priming effect of S1P at a low dosage for human umbilical cord-derived MSCs (UC-MSCs). A DNA-methylation inhibitor, 5-azacytidine (5-Aza), and VPA increased the expression of CXCR4 in UC-MSCs. In particular, UC-MSCs primed with a suboptimal dose (50 nM) of S1P in combination with 0.5 mM VPA (VPA+S1P priming), but not 1 µM 5-Aza, significantly improved the migration activity in response to stromal cell-derived factor 1 (SDF-1) concomitant with the activation of both MAPKp42/44 and AKT signaling cascades. Both epigenetic regulatory compounds had little influence on cell surface marker phenotypes and the multi-potency of UC-MSCs. In contrast, VPA+S1P priming of UC-MSCs potentiated the proliferation, colony forming unit-fibroblast, and anti-inflammatory activities, which were severely inhibited in the case of 5-Aza treatment. Accordingly, the VPA+S1P-primed UC-MSCs exhibited upregulation of a subset of genes related to stem cell migration and anti-inflammation response. Thus, the present study demonstrated that VPA enables MSC priming with S1P at a low dosage by enhancing their migration and other therapeutic beneficial activities. This priming strategy for MSCs may provide a more efficient and safe application of MSCs for treating a variety of intractable disorders.

  8. Synthesis and characterization of amino acid-functionalized calcium phosphate nanoparticles for siRNA delivery.

    Science.gov (United States)

    Bakan, Feray; Kara, Goknur; Cokol Cakmak, Melike; Cokol, Murat; Denkbas, Emir Baki

    2017-06-27

    Small interfering RNAs (siRNA) are short nucleic acid fragments of about 20-27 nucleotides, which can inhibit the expression of specific genes. siRNA based RNAi technology has emerged as a promising method for the treatment of a variety of diseases. However, a major limitation in the therapeutic use of siRNA is its rapid degradation in plasma and cellular cytoplasm, resulting in short half-life. In addition, as siRNA molecules cannot penetrate into the cell efficiently, it is required to use a carrier system for its delivery. In this work, chemically and morphologically different calcium phosphate (CaP) nanoparticles, including spherical-like hydroxyapatite (HA-s), needle-like hydroxyapatite (HA-n) and calcium deficient hydroxyapatite (CDHA) nanoparticles were synthesized by the sol-gel technique and the effects of particle characteristics on the binding capacity of siRNA were investigated. In order to enhance the gene loading efficiency, the nanoparticles were functionalized with arginine and the morphological and their structural characteristics were analyzed. The addition of arginine did not significantly change the particle sizes; however, it provided a significantly increased binding of siRNA for all types of CaP nanoparticles, as revealed by spectrophotometric measurements analysis. Arginine functionalized HA-n nanoparticles showed the best binding behavior with siRNA among the other nanoparticles due to its high, positive zeta potential (+18.8mV) and high surface area of Ca(++) rich "c" plane. MTT cytotoxicity assays demonstrated that all the nanoparticles tested herein were biocompatible. Our results suggest that high siRNA entrapment in each of the three modified non-toxic CaP nanoparticles make them promising candidates as a non-viral vector for delivering therapeutic siRNA molecules to treat cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC

    Science.gov (United States)

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular structure. The energy diffe...

  10. Safety and Efficacy of Cortisol Phosphate in Hyaluronic Acid Vehicle in the Treatment of Dry Eye in Sjogren Syndrome.

    Science.gov (United States)

    Rolando, Maurizio; Vagge, Aldo

    2017-06-01

    Evaluation of 0.3% cortisol phosphate eye drops in hyaluronic acid vehicle in the treatment of dry eye in Sjogren Syndrome. This prospective, single-center, masked (single blind), randomized controlled study included 40 female patients divided into 2 groups, group 1 treated with Idracemi, 0.3% cortisol phosphate eye drops twice a day, and group 2 treated with Cortivis, 0.3% cortisol phosphate in hyaluronic acid vehicle, with the same posology. Screening (day -7), randomization (day 0), follow-up (day 7), and termination (day 28) visits were conducted. Symptoms (VAS) questionnaire, tear film breakup time, corneo-conjunctival stain, intraocular pressure (IOP) measurement, and fundus examination were performed at each visit. Conjunctival impression cytology for human leukocyte antigen-DR (HLA-DR) expression at visit 1 and 4 was also performed. No changes in IOP or fundus examination were observed in either group at each time point. Group 1 showed at day 28 a statistically significant amelioration of symptoms and reduction of HLA-DR expression. Group 2 showed at day 7 statistically significant improvement of corneal and conjunctival stain versus baseline and versus group 1; the symptom score was statistically significantly better than baseline and versus group 1 after 28 days too. The HLA-DR expression and the epithelial cell area were statistically significantly reduced versus baseline and versus group 1 at the same time. Cortisol phosphate proved to be safe and effective in treating dry eye in Sjogren Syndrome patients in both formulations. However, the formula with hyaluronic acid vehicle proved to be more effective. Both formulations were very well tolerated.

  11. Phosphate supply explains variation in nucleic acid allocation but not C : P stoichiometry in the western North Atlantic

    Science.gov (United States)

    Zimmerman, A. E.; Martiny, A. C.; Lomas, M. W.; Allison, S. D.

    2014-03-01

    Marine microbial communities mediate many biogeochemical transformations in the ocean. Consequently, processes such as primary production and carbon (C) export are linked to nutrient regeneration and are influenced by the resource demand and elemental composition of marine microbial biomass. Laboratory studies have demonstrated that differential partitioning of element resources to various cellular components can directly influence overall cellular elemental ratios, especially with respect to growth machinery (i.e., ribosomal RNA) and phosphorus (P) allocation. To investigate whether allocation to RNA is related to biomass P content and overall C : P biomass composition in the open ocean, we characterized patterns of P allocation and C : P elemental ratios along an environmental gradient of phosphate supply in the North Atlantic subtropical gyre (NASG) from 35.67° N, 64.17° W to 22.676° N, 65.526° W. Because the NASG is characterized as a P-stressed ecosystem, we hypothesized that biochemical allocation would reflect sensitivity to bioavailable phosphate, such that greater phosphate supply would result in increased allocation toward P-rich RNA for growth. We predicted these changes in allocation would also result in lower C : P ratios with increased phosphate supply. However, bulk C : P ratios were decoupled from allocation to nucleic acids and did not appear to vary systematically across a phosphate supply gradient of 2.2-14.7 μmol m-2 d-1. Overall, we found that C : P ratios ranged from 188 to 306 along the transect, and RNA represented only 6-12% of total particulate P, whereas DNA represented 11-19%. We did find that allocation to RNA was positively correlated with phosphate supply rate, suggesting a consistent physiological response in biochemical allocation to resource supply within the whole community. These results suggest that community composition and/or nonnucleic acid P pools may influence ecosystem-scale variation in C : P stoichiometry more than

  12. Continuous monitoring of the zinc-phosphate acid-base cement setting reaction by proton nuclear magnetic relaxation

    Science.gov (United States)

    Apih, T.; Lebar, A.; Pawlig, O.; Trettin, R.

    2001-06-01

    Proton nuclear magnetic relaxation is a well-established technique for continuous and non destructive monitoring of hydration of conventional Portland building cements. Here, we demonstrate the feasibility of nuclear magnetic resonance (NMR) monitoring of the setting reaction of zinc-phosphate acid-base dental cements, which harden in minutes as compared to days, as in the case of Portland cements. We compare the setting of cement powder (mainly, zinc oxide) prepared with clinically used aluminum-modified orthophosphoric acid solution with the setting of a model system where cement powder is mixed with pure orthophosphoric acid solution. In contrast to previously published NMR studies of setting Portland cements, where a decrease of spin-lattice relaxation time is attributed to enhanced relaxation at the growing internal surface, spin-lattice relaxation time T1 increases during the set of clinically used zinc-phosphate cement. Comparison of these results with a detailed study of diffusion, viscosity, and magnetic-field dispersion of T1 in pure and aluminum-modified orthophosphoric acid demonstrates that the increase of T1 in the setting cement is connected with the increase of molecular mobility in the residual phosphoric acid solution. Although not taken into account so far, such effects may also significantly influence the relaxation times in setting Portland cements, particularly when admixtures with an effect on water viscosity are used.

  13. Nickel-catalyzed cross-coupling of aryl phosphates with arylboronic acids.

    Science.gov (United States)

    Chen, Hu; Huang, Zhongbin; Hu, Xiaoming; Tang, Guo; Xu, Pengxiang; Zhao, Yufen; Cheng, Chien-Hong

    2011-04-01

    The Suzuki-Miyaura cross-coupling of aryl phosphates using Ni(PCy(3))(2)Cl(2) as an inexpensive, bench-stable catalyst is described. Broad substrate scope and high efficiency are demonstrated by the syntheses of more than 40 biaryls and by constructing complex organic molecules. The poor reactivity of aryl phosphates relative to aryl halides is successfully employed to construct polyarenes by selective cross-coupling using Pd and Ni catalysts.

  14. Photoactive layer-by-layer films of cellulose phosphate and titanium dioxide containing phosphotungstic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Sajjad [Instituto de Química de São Carlos, Universidade de São Paulo, PO Box 780, São Carlos, São Paulo 13564-970 (Brazil); Acuña, José Javier Sáez [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo Andre, Sao Paulo, 09210-170 (Brazil); Pasa, André Avelino [Surface and Thin Film Laboratory, Physics Department, Federal University of Santa Catarina, PO Box 476, Florianópolis, SC 88040-900 (Brazil); Bilmes, Sara A. [Universidad de Buenos Aires, Facultad Ciencias Exactas y Naturales, Instituto de Química Física de los Materiales, Medio Ambiente y Energía – INQUIMAE, Ciudad Universitaria, Pab. 2, Buenos Aires C1428EHA (Argentina); Vela, Maria Elena; Benitez, Guillermo [Laboratorio de Nanoscopías y Fisicoquímica de Superficies, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata – CONICET, diagonal 113 esquina 64. C.C.16.Suc.4, 1900 La Plata (Argentina); Rodrigues-Filho, Ubirajara Pereira, E-mail: uprf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, PO Box 780, São Carlos, São Paulo 13564-970 (Brazil)

    2013-07-15

    A versatile layer-by-layer (LbL) procedure for the preparation of highly dispersed, adherent and porous multilayer films of TiO{sub 2} nanoparticles (NPs) and phosphotungstic acid (HPW) on a variety of substrates at room temperature was developed based on the use of cellulose phosphate (CP) as an efficient and non-conventional polyelectrolyte. UV/vis absorption spectroscopy confirmed the linear and regular growth of the films with the number of immersion cycles and a strong adsorption ability of CP towards TiO{sub 2} NPs. FTIR spectroscopy showed that HPW binds to the surface of TiO{sub 2} through the oxygen atom at the corner of the Keggin structure. XPS results showed that the interaction between TiO{sub 2} and CP is through Ti–O–P linkage. A model is proposed for the TiO{sub 2}–HPW interaction based on XPS and FTIR results. FEG/SEM study of the surface morphology revealed a porous film structure with a homogenous distribution of the TiO{sub 2} NPs induced by CP. HRTEM studies showed that the resulting composite films consist of crystalline anatase and rutile phases and poly-nano-crystalline HPW with a semi-crystalline TiO{sub 2}–HPW interface. These CP/TiO{sub 2} and CP/TiO{sub 2}/HPW LbL films showed good photoactivity against both saturated and unsaturated species, for instance, stearic acid (SA), crystal violet (CV) and methylene blue (MB) under UV irradiation. The CP/HPW films formed on bacterial cellulose (BC) showed good photochromic response which is enhanced in presence of TiO{sub 2} due to an interfacial electron transfer from TiO{sub 2} to HPW. This simple and environmentally safe method can be used to form coatings on a variety of surfaces with photoactive TiO{sub 2} and TiO{sub 2}/HPW films.

  15. Influence of triethyl phosphate on phosphatase activity in shooting range soil: Isolation of a zinc-resistant bacterium with an acid phosphatase.

    Science.gov (United States)

    Story, Sandra; Brigmon, Robin L

    2017-03-01

    Phosphatase-mediated hydrolysis of organic phosphate may be a viable means of stabilizing heavy metals via precipitation as a metal phosphate in bioremediation applications. We investigated the effect of triethyl phosphate (TEP) on soil microbial-phosphatase activity in a heavy-metal contaminated soil. Gaseous TEP has been used at subsurface sites for bioremediation of organic contaminants but not applied in heavy-metal contaminated areas. Little is known about how TEP affects microbial activity in soils and it is postulated that TEP can serve as a phosphate source in nutrient-poor groundwater and soil/sediments. Over a 3-week period, TEP amendment to microcosms containing heavy-metal contaminated soil resulted in increased activity of soil acid-phosphatase and repression of alkaline phosphatase, indicating a stimulatory effect on the microbial population. A soil-free enrichment of microorganisms adapted to heavy-metal and acidic conditions was derived from the TEP-amended soil microcosms using TEP as the sole phosphate source and the selected microbial consortium maintained a high acid-phosphatase activity with repression of alkaline phosphatase. Addition of 5mM zinc to soil-free microcosms had little effect on acid phosphatase but inhibited alkaline phosphatase. One bacterial member from the consortium, identified as Burkholderia cepacia sp., expressed an acid-phosphatase activity uninhibited by high concentrations of zinc and produced a soluble, indigo pigment under phosphate limitation. The pigment was produced in a phosphate-free medium and was not produced in the presence of TEP or phosphate ion, indicative of purple acid-phosphatase types that are pressed by bioavailable phosphate. These results demonstrate that TEP amendment was bioavailable and increased overall phosphatase activity in both soil and soil-free microcosms supporting the possibility of positive outcomes in bioremediation applications.

  16. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates

    Science.gov (United States)

    Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1993-01-01

    The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

  17. Crystal growth, structural and thermal studies of amino acids admixtured L-arginine phosphate monohydrate single crystals

    Science.gov (United States)

    Anandan, P.; Saravanan, T.; Parthipan, G.; Kumar, R. Mohan; Bhagavannarayana, G.; Ravi, G.; Jayavel, R.

    2011-05-01

    To study the improved characteristics of L-arginine phosphate monohydrate (LAP) crystals, amino acids mixed LAP crystals have been grown by slow cooling method. Amino acids like glycine, L-alanine, and L-valine have been selected for doping. Optical quality bulk crystals have been harvested after a typical growth period of about twenty days. The effect of amino acids in the crystal lattice and molecular vibrational frequencies of various functional groups in the crystals have been studied using X-ray powder diffraction and Fourier Transform infrared (FTIR) analyses respectively. Thermal behavior of the amino acids mixed LAP crystals have been studied from the TG and DTG analyses. High-resolution X-ray diffraction studies have been carried out to find the crystalline nature. Optical transmission studies have been carried out by UV-vis spectrophotometer. The cut off wavelength is below 240 nm for the grown crystals.

  18. Crystallization of dicalcium phosphate dihydrate with presence of glutamic acid and arginine at 37 °C.

    Science.gov (United States)

    Li, Chengfeng; Ge, Xiaolu; Li, Guochang; Bai, Jiahai; Ding, Rui

    2014-08-01

    The formations of non-metabolic stones, bones and teeth were seriously related to the morphology, size and surface reactivity of dicalcium phosphate dihydrate (DCPD). Herein, a facile biomimetic mineralization method with presence of glutamic acid and arginine was employed to fabricate DCPD with well-defined morphology and adjustable crystallite size. In reaction solution containing more arginine, crystallization of DCPD occurred with faster rate of nucleation and higher density of stacked layers due to the generation of more OH(-) ions after hydrolysis of arginine at 37 °C. With addition of fluorescein or acetone, the consumption of OH(-) ions or desolvation reaction of Ca(2+) ions was modulated, which resulted in the fabrication of DCPD with adjustable crystallite sizes and densities of stacked layers. In comparison with fluorescein-loading DCPD, dicalcium phosphate anhydrate was prepared with enhanced photoluminescence properties due to the reduction of self-quenching effect and regular arrangement of encapsulated fluorescein molecules. With addition of more acetone, DCPD was prepared with smaller crystallite size via antisolvent crystallization. The simulated process with addition of amino acids under 37 °C would shed light on the dynamic process of biomineralization for calcium phosphate compounds.

  19. Glycerol-3-phosphate acyltransferase-2 is expressed in spermatic germ cells and incorporates arachidonic acid into triacylglycerols.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Cattaneo

    Full Text Available BACKGROUND: De novo glycerolipid synthesis begins with the acylation of glycerol-3 phosphate catalyzed by glycerol-3-phosphate acyltransferase (GPAT. In mammals, at least four GPAT isoforms have been described, differing in their cell and tissue locations and sensitivity to sulfhydryl reagents. In this work we show that mitochondrial GPAT2 overexpression in CHO-K1 cells increased TAG content and both GPAT and AGPAT activities 2-fold with arachidonoyl-CoA as a substrate, indicating specificity for this fatty acid. METHODS AND RESULTS: Incubation of GPAT2-transfected CHO-K1 cells with [1-(14C]arachidonate for 3 h increased incorporation of [(14C]arachidonate into TAG by 40%. Consistently, arachidonic acid was present in the TAG fraction of cells that overexpressed GPAT2, but not in control cells, corroborating GPAT2's role in synthesizing TAG that is rich in arachidonic acid. In rat and mouse testis, Gpat2 mRNA was expressed only in primary spermatocytes; the protein was also detected in late stages of spermatogenesis. During rat sexual maturation, both the testicular TAG content and the arachidonic acid content in the TAG fraction peaked at 30 d, matching the highest expression of Gpat2 mRNA and protein. CONCLUSIONS: These results strongly suggest that GPAT2 expression is linked to arachidonoyl-CoA incorporation into TAG in spermatogenic germ cells.

  20. Cytotoxicity detection of poly(lactic-co-glycolic acid/tricalcium phosphate

    Directory of Open Access Journals (Sweden)

    Meng SUN

    2011-12-01

    Full Text Available Objective To detecte the cytotoxicity of the PLGA/TCP(poly(lactic-co-glycolic acid/Tricalcium phosphate composite that based on the precedent experiments conducted in Tsinghua University.Methods Compared with the PLGA scaffold material,observated the surface and interior structure of the PLGA/TCP scaffold material by SEM(scanning electron microscope,the surface and interior of PLGA/TCP scaffold material appeared to be homogeneous porous under SEM,with fairly even porosity distribution.The pore diameter was approximately 400μm.The interpenetrative micro-pores were scattered over bigger pores’ periphery with approximately circular contour and 3~5 μm in diameter.These pores were interpenetrative,the average factor of porosity was 89.6%.And which selected rat L929 cell strain,and detected the cytotoxicity of the PLGA/TCP composite in vitro by MTT method.Results The surface and interior of PLGA/TCP scaffold material appeared to be homogeneous porous under SEM,with fairly even porosity distribution.The pore diameter was approximately 400μm.The interpenetrative micro-pores were scattered over bigger pores’ periphery with approximately circular contour and 3~5 μm in diameter.These pores were interpenetrative,the average factor of porosity was 89.6%.On rat L929 cell strain,used MTT Method to detect the cytotoxicity of the composite PLGA/ TCP in vitro,the result showed that the cytotoxicity of the PLGA/TCP composite was level I,according to the criterion,it can be considered as non cytotoxic.Conclusion This research has proved that the PLGA/TCP compound scaffold material has a more homogeneous structure,with the vesicular interior and the structure of PLGA/TCP composite is similar to natural bone trabecula,PLGA/TCP is non cytotoxicity,which satisfy the basic requirement of biological material application and provides a good experimental foundation for repairing autologous bone defect in the near future.

  1. Mineral phosphate solubilizing bacterial community in agro-ecosystem

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... patterns. Four insoluble phosphate sources; purulia rock phosphate (PRP), mussourie rock phosphate .... phosphate in gradient soils, there might be changes in ..... resistance properties, fatty acid profiling and nucleic acid.

  2. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    Science.gov (United States)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43- level. The statistical significance of the correlation with groundwater PO43- concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (PStructural equation modeling for example could be used to understand the practical importance of individual soil, management and hydrological potential predictors of groundwater PO4.

  3. The oxygen isotope composition of phosphate released from phytic acid by the activity of wheat and Aspergillus niger phytase

    Directory of Open Access Journals (Sweden)

    C. v. Sperber

    2015-03-01

    Full Text Available Phosphorus (P is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi from organic phosphorus compounds (Porg. Phytic acid (IP6 is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields plant available inorganic phosphate (Pi and less phosphorylated inositol derivates as products. The hydrolysis of organic P-compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'monophosphate (AMP and glycerophosphate (GPO4 as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as substrate were prepared. During the hydrolysis of IP6 by phytase, four Pi are released, and one oxygen atom from water is incorporated into each Pi. This incorporation of oxygen from water into Pi is subject to an apparent inverse isotopic fractionation (ϵ ∼ 6 to 10‰, which is similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ∼ 7‰ where less than three Pi are released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ∼ −12‰, again similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ε to the same amino acid sequence motif (RHGXRXP at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking substrate

  4. The bone-regenerative properties of Emdogain adsorbed onto poly(D,L-lactic-coglycolic acid)/calcium phosphate composites in an ectopic and an orthotopic rat model.

    NARCIS (Netherlands)

    Plachokova, A.S.; Dolder, J. van den; Jansen, J.A.

    2008-01-01

    BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the bone-regenerative properties of Emdogain in osseous and nonosseous sites. MATERIAL AND METHODS: For the orthotopic study, unloaded poly(D,L-lactic-coglycolic acid)/calcium phosphate implants, and poly(D,L-lactic-coglycolic acid)/cal

  5. Effect of medium acidity on the thermodynamics and kinetics of the reaction of pyridoxal 5'-phosphate with isoniazid in an aqueous solution

    Science.gov (United States)

    Gamov, G. A.; Zavalishin, M. N.; Usacheva, T. R.; Sharnin, V. A.

    2017-05-01

    Thermodynamic characteristics of the formation of the Schiff base between isoniazid and pyridoxal 5'-phosphate in an aqueous solution at different pH values of a medium are determined by means of spectrophotometry and calorimetric titration. The process kinetics is studied spectrophotometrically, and the reaction rate constants for the formation of the imine at different acidities of a medium are determined. Biochemical aspects of the binding of pyridoxal 5'-phosphate into stable compounds are discussed.

  6. Effect of Mg2+ on acidic calcium phosphate phases grown by electrodeposition

    Science.gov (United States)

    Correia, Matheus Bento; Júnior, José Pedro Gualberto; Macedo, Michelle Cardinale S. S.; Resende, Cristiane Xavier; dos Santos, Euler Araujo

    2017-10-01

    In this work, the effect of Mg2+ ions on the electrodeposition of dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP) and calcium-deficient hydroxyapatite (CDHA) crystals on a commercially pure titanium (cp-Ti) substrate was evaluated. We demonstrated that Mg2+ ions could change the morphology of the coatings by inhibiting the growth rate of the OCP and CDHA crystals and diminishing the crystallite size of DCPD. The inhibition effect on OCP and CDHA was most likely due to a surface adsorption mechanism since no evidence of a doping process was observed using Rietveld refinement and electron diffraction analyses. Conversely, the presence of Mg2+ ions generated a favorable condition for the nucleation of a new Mg2+-rich DCPD crystal population, presenting smaller crystallite sizes.

  7. Organic acids inhibit the formation of pyromorphite and Zn-phosphate in phosphorous amended Pb- and Zn-contaminated soil.

    Science.gov (United States)

    Debela, F; Arocena, J M; Thring, R W; Whitcombe, T

    2013-02-15

    Pyromorphite (PY) and some zinc phosphates (Zn-P) are very sparingly soluble minerals and hence can immobilize Pb and Zn in contaminated soils. However, mechanisms leading to the poor efficiency of PY and Zn-P formation in contaminated soils amended with P still remain unclear. We studied the influence of two low molecular weight organic acids (LMWOA) - oxalic acid and citric acid and diethylene triamine pentaacetic acid (DTPA) - in PY and Zn-P formation in a P-amended contaminated soil. Despite the high levels of metals (∼4% Pb and 21% Zn) in the study soil, the addition of up to 1% inorganic P transformed only up to 37% and 17% of the total Pb and Zn to PY and Zn-P, respectively. Semi-quantitative estimates from a linear combination fitting of X-ray absorption near edge spectra (LC-XANES fitting) showed that the formation of PY decreased from 37% to 3% of the total Pb in the presence of oxalic acid and the addition of 1% P. The reduced PY formation may be associated with the increase in organic-bound Pb from 9% to 54% and decrease in carbonate associated Pb from 42% to 12% with oxalic acid addition as indicated by a chemical sequential extraction (SE) technique. Citric acid seemed to have a less adverse effect in PY formation than oxalic acid. Our data also suggests both oxalic and citric acids have less adverse effects on the efficiency of Zn-P formation. From this study we conclude that the abundance of LMWOA in soil environments can be one factor contributing to the poor efficiency of P amendments practices to effectively immobilize Pb and Zn in metal contaminated soils.

  8. Cs salt of tungstophosphoric acid-promoted zirconium titanium phosphate solid acid catalyst: An active catalyst for the synthesis of bisphenols

    Indian Academy of Sciences (India)

    Niranjan Biswal; Dipti Prakasini Das; Kulamani Parida

    2014-03-01

    A series of novel CsTPA-ZTP ( = 30, 40, 50, 60 and 80 wt%) solid acid composite catalysts were synthesized by ion-exchange process using cesium nitrate, tungstophosphoric acid (TPA), zirconium titanium phosphate (ZTP) with varied surface areas, acidities and microstructures. Detailed characterizations of the composite catalysts were done by Powder X-ray Diffraction (PXRD), Fourier Transform Infrared (FTIR) Spectroscopy, N2 adsorption desorption, Scanning Electron Microscopy (SEM-EDS) analysis, X-ray Photoelectron Spectroscopy (XPS) and Temperature Programmed Desorption (TPD).We have studied the catalytic activities, kinetics and reusability of the catalysts. 60CsTPA-ZTP is found to be an effective and re-usable catalyst for the synthesis of bisphenol A (BPA) and bisphenol F (BPF) using acetonitrile as solvent.

  9. Phosphate Starvation Responses and Gibberellic Acid Biosynthesis Are Regulated by the MYB62 Transcription Factor in Arabiclopsis

    Institute of Scientific and Technical Information of China (English)

    Ballachanda N. Devaiah; Ramaiah Madhuvanthi; Athikkattuvalasu S. Karthikeyan; Kashchandra G. Raghothama

    2009-01-01

    The limited availability of phosphate (Pi) in most soils results in the manifestation of Pi starvation responses in plants. To dissect the transcriptional regulation of Pi stress-response mechanisms, we have characterized the biological role of MYB62, an R2R3-type MYB transcription factor that is induced in response to Pi deficiency. The induction of MYB62 is a specific response in the leaves during Pi deprivation. The MYB62 protein localizes to the nucleus. The overexpression of MYB62 resulted in altered root architecture, Pi uptake, and acid phosphatase activity, leading to decreased total Pi content in the shoots. The expression of several Pi starvation-induced (PSI) genes was also suppressed in the MYB62 overexpressing plants. Overexpression of MYB62 resulted in a characteristic gibberellic acid (GA)-deficient phenotype that could be partially reversed by exogenous application of GA. In addition, the expression of SOC1 and SUPERMAN, molecular regulators of flowering, was suppressed in the MYB62 overexpressing plants. Interestingly, the expression of these genes was also reduced during Pi deprivation in wild-type plants, suggesting a role for GA biosynthetic and floral regulatory genes in Pi starvation responses. Thus, this study highlights the role of MYB62 in the regulation of phosphate starvation responses via changes in GA metabolism and signaling. Such cross-talk between Pi homeostasis and GA might have broader implications on flowering, root development and adaptive mechanisms during nutrient stress.

  10. Investigating the use of coupling agents to improve the interfacial properties between a resorbable phosphate glass and polylactic acid matrix.

    Science.gov (United States)

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew J; Rudd, Chris D; Walker, Gavin S; Scotchford, Colin A

    2013-09-01

    Eight different chemicals were investigated as potential candidate coupling agents for phosphate glass fibre reinforced polylactic acid composites. Evidence of reaction of the coupling agents with phosphate glass and their effect on surface wettability and glass degradation were studied along with their principle role of improving the interface between glass reinforcement and polymer matrix. It was found that, with an optimal amount of coupling agent on the surface of the glass/polymer, interfacial shear strength improved by a factor of 5. Evidence of covalent bonding between agent and glass was found for three of the coupling agents investigated, namely: 3-aminopropyltriethoxysilane; etidronic acid and hexamethylene diisocyanate. These three coupling agents also improved the interfacial shear strength and increased the hydrophobicity of the glass surface. It is expected that this would provide an improvement in the macroscopic properties of full-scale composites fabricated from the same materials which may also help to retain these properties for the desired length of time by retarding the breakdown of the fibre/matrix interface within these composites.

  11. Why nature chose phosphates.

    Science.gov (United States)

    Westheimer, F H

    1987-03-06

    Phosphate esters and anhydrides dominate the living world but are seldom used as intermediates by organic chemists. Phosphoric acid is specially adapted for its role in nucleic acids because it can link two nucleotides and still ionize; the resulting negative charge serves both to stabilize the diesters against hydrolysis and to retain the molecules within a lipid membrane. A similar explanation for stability and retention also holds for phosphates that are intermediary metabolites and for phosphates that serve as energy sources. Phosphates with multiple negative charges can react by way of the monomeric metaphosphate ion PO3- as an intermediate. No other residue appears to fulfill the multiple roles of phosphate in biochemistry. Stable, negatively charged phosphates react under catalysis by enzymes; organic chemists, who can only rarely use enzymatic catalysis for their reactions, need more highly reactive intermediates than phosphates.

  12. 多聚磷酸法合成醇醚磷酸单酯%Synthesis of alcohol ether phosphate monoester phosphate by polyphosphoric acid method

    Institute of Scientific and Technical Information of China (English)

    徐进云; 宁庆然; 郑帼; 孙玉; 彭浩凯

    2015-01-01

    采用直接酯化法,以多聚磷酸和脂肪醇醚为原料合成了高含量单醇醚磷酸酯,并设计正交实验考察了合成工艺条件对单酯含量和醇醚转化率的影响;研究了不同单酯含量、pH值和含油率对芳砜纶纤维的抗静电性影响,并利用环境扫描电子显微镜和扫描隧道显微镜对醚磷酸酯钾盐浸丝处理后的芳砜纶纤维表面形貌特征进行了表征.结果表明:醇醚和多聚磷酸酯化反应的最优化条件为投料比3∶1,反应温度80℃,反应时间4 h,此时磷酸酯产品中单酯质量分数为91.8%,醇醚转化率为95%;磷酸酯钾盐的单酯含量和纤维表面的含油率比磷酸酯钾盐的pH值对芳砜纶纤维的抗静电性能影响大,综合考虑,纤维最佳含油率为0.3%,磷酸酯钾盐单酯含量越高,纤维的抗静电性能越好.%The high monoester content of alcohol ether phosphate was synthesized by direct esterification,using polyphosphoric acid and fatty alcohol ether as starting materials. The conditions on content of monoester and conversion rate of alcohol ether were investigated by orthogonal experimental analyses. In addition,the influences on the antistatic property of polysulfonamide fiber (PSF) by monoester content,pH value and oil content were explored. Simultaneously, environmental scanning electron microscope (ESEM) and scanning tunneling microscope (STM) were used to characterize the surface topography of PSF after dipping treatment by alcohol ether phosphate. The results showed that the optimum of esterification was the ratio of alcohol ether to polyphosphoric acid is 3∶1,the reaction temperature is 80 ℃ and the reaction time is 4 h,with the monoester content of optimal product and the percent conversion of alcohol ether being 91.8%! and 95%! respectively. Furthermore,the monoester content and oil content had greater impact on antistatic property PSF of than the pH value,and the best oil content was 0.3%!and

  13. Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged alpha-zirconium phosphate.

    Science.gov (United States)

    Hayashi, A; Fujimoto, Y; Ogawa, Y; Nakayama, H; Tsuhako, M

    2005-03-01

    Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acidacidacidacid, whereas the adsorption amount of formaldehyde was the same as that of butyric acid. It was cleared that the adsorbed formaldehyde was partially decomposed to formic acid and methanol by self oxidation-reduction reaction in the interlayer region as evidenced by solid-state NMR. Thereby the interlayer distance after the adsorption of formaldehyde expanded to 14.4 A. In the case of formic acid, it was cointercalated into the interlayer region, and the interlayer distance expanded to 11.1 A. On the other hand, the interlayer distance of the other carboxylic acid-adsorbed compounds decreased to 7.6 A due to release by the evacuation.

  14. Separative recovery with lime of phosphate and fluoride from an acidic effluent containing H3PO4, HF and/or H2SiF6.

    Science.gov (United States)

    Gouider, Mbarka; Feki, Mongi; Sayadi, Sami

    2009-10-30

    Fluoride content and flow-rate of fertilizer plant wastewater from phosphoric acid and/or triple superphosphate (TSP) production lead to the discharge of several thousand tons of fluoride (F(-)) per year and even more for phosphate (PO4(3-)). Since sustainability is an important environmental concern, the removal methods should allow phosphorus and fluoride to be recycled as a sustainable products for use as raw materials either in agricultural or industrial applications. In the present work, separative recovery with lime of these two target species was investigated. A preliminary speciation study, carried out on the crude effluent, showed that two forms of fluoride: HF and H2SiF6 are present in a highly acidic medium (pH approximately 2). Evidence that fluoride is present under both free (HF) and combined (H2SiF6) forms, in the phosphate-containing effluent, was provided by comparing potentiometric titration curves of a crude wastewater sample and synthetic acid mixtures containing H3PO4, HF and H2SiF6. In a second step synthetic effluent containing mixtures of the following acids: HF, H2SiF6 and H3PO4, were treated with lime. The behaviour of these compounds under lime treatment was analysed. The data showed that fluoride has a beneficial effect on phosphate removal. Moreover, by acting on the precipitation pH, a "selective" recovery of fluoride and phosphate ions was possible either from phosphoric acid/hydrofluoric acid or phosphoric acid/hexafluorosilicic acid mixtures. Indeed, the first stage of the separative recovery, led to a fluoride removal efficiency of 97-98% from phosphoric acid/hydrofluoric acid mixture. It was of 93-95% from phosphoric acid/hexafluorosilicic acid mixture. During the second stage, the phosphate precipitation reached 99.8% from both acidic mixtures whereas it did not exceed 82% from a solution containing H3PO4 alone. The XRD and IR analyses showed that during lime treatment, a H2SiF6 hydrolysis occurred, instead of CaSiF6 solid

  15. Mechanical Behavior and Thermal Stability of Acid-Base Phosphate Cements and Composites Fabricated at Ambient Temperature

    Science.gov (United States)

    Colorado Lopera, Henry Alonso

    This dissertation presents the study of the mechanical behavior and thermal stability of acid-base phosphate cements (PCs) and composites fabricated at ambient temperature. These materials are also known as chemically bonded phosphate ceramics (CBPCs). Among other advantages of using PCs when compared with traditional cements are the better mechanical properties (compressive and flexural strength), lower density, ultra-fast (controllable) setting time, controllable pH, and an environmentally benign process. Several PCs based on wollastonite and calcium and alumino phosphates after thermal exposure up to 1000°C have been investigated. First, the thermo-mechanical and chemical stability of wollastonite-based PC (Wo-PC) exposed to temperatures up to 1000°C in air environment were studied. The effects of processing conditions on the curing and shrinkage of the wollastonite-based PC were studied. The chemical reactions and phase transformations during the fabrication and during the thermal exposure are analyzed in detail using scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA Then, the thermo-mechanical and chemical stability of glass, carbon and basalt fiber reinforced Wo-PC composites, were studied using SEM, XRD, TGA. The flexural strength and Weibull statistics were analyzed. A significant strength degradation in the composites were found after the thermal exposure at elevated temperatures due to the interdifusion and chemical reactions across the fibers and the matrix at temperatures over 600°C. To overcome this barrier, we have developed a new PC based on calcium and alumino-phosphates (Ca-Al PCs). The Ca-Al PCs were studied in detail using SEM, XRD, TGA, curing, shrinkage, Weibull statistics, and compression tests. Our study has confirmed that this new composite material is chemically and mechanically stable at temperatures up to 1000°C. Moreover, the compression strength increases after exposure to 1000

  16. Effect of surface modification of nanofibres with glutamic acid peptide on calcium phosphate nucleation and osteogenic differentiation of marrow stromal cells.

    Science.gov (United States)

    Karaman, Ozan; Kumar, Ankur; Moeinzadeh, Seyedsina; He, Xuezhong; Cui, Tong; Jabbari, Esmaiel

    2016-02-01

    Biomineralization is mediated by extracellular matrix (ECM) proteins with amino acid sequences rich in glutamic acid. The objective of this study was to investigate the effect of calcium phosphate deposition on aligned nanofibres surface-modified with a glutamic acid peptide on osteogenic differentiation of rat marrow stromal cells. Blend of EEGGC peptide (GLU) conjugated low molecular weight polylactide (PLA) and high molecular weight poly(lactide-co-glycolide) (PLGA) was electrospun to form aligned nanofibres (GLU-NF). The GLU-NF microsheets were incubated in a modified simulated body fluid for nucleation of calcium phosphate crystals on the fibre surface. To achieve a high calcium phosphate to fibre ratio, a layer-by-layer approach was used to improve diffusion of calcium and phosphate ions inside the microsheets. Based on dissipative particle dynamics simulation of PLGA/PLA-GLU fibres, > 80% of GLU peptide was localized to the fibre surface. Calcium phosphate to fibre ratios as high as 200%, between those of cancellous (160%) and cortical (310%) bone, was obtained with the layer-by-layer approach. The extent of osteogenic differentiation and mineralization of marrow stromal cells seeded on GLU-NF microsheets was directly related to the amount of calcium phosphate deposition on the fibres prior to cell seeding. Expression of osteogenic markers osteopontin, alkaline phosphatase (ALP), osteocalcin and type 1 collagen increased gradually with calcium phosphate deposition on GLU-NF microsheets. Results demonstrate that surface modification of aligned synthetic nanofibres with EEGGC peptide dramatically affects nucleation and growth of calcium phosphate crystals on the fibres leading to increased osteogenic differentiation of marrow stromal cells and mineralization.

  17. The oxygen isotope composition of phosphate released from phytic acid by the activity of wheat and Aspergillus niger phytase

    Science.gov (United States)

    von Sperber, C.; Tamburini, F.; Brunner, B.; Bernasconi, S. M.; Frossard, E.

    2015-07-01

    Phosphorus (P) is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi) from organic phosphorus compounds (Porg). Phytic acid (myo-inositol hexakisphosphate, IP6) is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields available Pi and less phosphorylated inositol derivates as products. The hydrolysis of organic P compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O) of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'-monophosphate (AMP) and glycerophosphate (GPO4) as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as a substrate were prepared. During the hydrolysis of IP6 by phytase, four of the six Pi were released, and one oxygen atom from water was incorporated into each Pi. This incorporation of oxygen from water into Pi was subject to an apparent inverse isotopic fractionation (ϵ ~ 6 to 10 ‰), which was similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ~ 7 ‰), where less than three Pi were released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ~ -12 ‰), similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ϵ to the same amino acid sequence motif (RHGXRXP) at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking

  18. Bile Acid-Mediated Sphingosine-1-Phosphate Receptor 2 Signaling Promotes Neuroinflammation during Hepatic Encephalopathy in Mice

    Directory of Open Access Journals (Sweden)

    Matthew McMillin

    2017-07-01

    Full Text Available Hepatic encephalopathy (HE is a neuropsychiatric complication that occurs due to deteriorating hepatic function and this syndrome influences patient quality of life, clinical management strategies and survival. During acute liver failure, circulating bile acids increase due to a disruption of the enterohepatic circulation. We previously identified that bile acid-mediated signaling occurs in the brain during HE and contributes to cognitive impairment. However, the influences of bile acids and their downstream signaling pathways on HE-induced neuroinflammation have not been assessed. Conjugated bile acids, such as taurocholic acid (TCA, can activate sphingosine-1-phosphate receptor 2 (S1PR2, which has been shown to promote immune cell infiltration and inflammation in other models. The current study aimed to assess the role of bile-acid mediated S1PR2 signaling in neuroinflammation and disease progression during azoxymethane (AOM-induced HE in mice. Our findings demonstrate a temporal increase of bile acids in the cortex during AOM-induced HE and identified that cortical bile acids were elevated as an early event in this model. In order to classify the specific bile acids that were elevated during HE, a metabolic screen was performed and this assay identified that TCA was increased in the serum and cortex during AOM-induced HE. To reduce bile acid concentrations in the brain, mice were fed a diet supplemented with cholestyramine, which alleviated neuroinflammation by reducing proinflammatory cytokine expression in the cortex compared to the control diet-fed AOM-treated mice. S1PR2 was expressed primarily in neurons and TCA treatment increased chemokine ligand 2 mRNA expression in these cells. The infusion of JTE-013, a S1PR2 antagonist, into the lateral ventricle prior to AOM injection protected against neurological decline and reduced neuroinflammation compared to DMSO-infused AOM-treated mice. Together, this identifies that reducing bile acid

  19. New, efficient synthesis of oseltamivir phosphate (Tamiflu) via enzymatic desymmetrization of a meso-1,3-cyclohexanedicarboxylic acid diester.

    Science.gov (United States)

    Zutter, Ulrich; Iding, Hans; Spurr, Paul; Wirz, Beat

    2008-07-04

    A new, enantioselective synthesis of the influenza neuraminidase inhibitor prodrug oseltamivir phosphate 1 (Tamiflu) and its enantiomer ent-1 starting from cheap, commercially available 2,6-dimethoxyphenol 10 is described. The main features of this approach comprise the cis-hydrogenation of 5-(1-ethyl-propoxy)-4,6-dimethoxy-isophthalic acid diethyl ester (6a) and the desymmetrization of the resultant all-cis meso-diesters 7a and 7b, respectively. Enzymatic hydrolysis of the meso-diester 7b with pig liver esterase afforded the (S)-monoacid 8b, which was converted into cyclohexenol 17 via a Curtius degradation and a base-catalyzed decarboxylative elimination of the Boc-protected oxazolidinone 14. Introduction of the second amino function via S(N)2 substitution of the corresponding triflate 18 with NaN3 followed by azide reduction, N-acetylation, and Boc-deprotection gave oseltamivir phosphate 1 in a total of 10 steps and an overall yield of approximately 30%. The enantiomer ent-1 was similarly obtained via an enzymatic desymmetrization of meso-diester 7a with Aspergillus oryzae lipase, providing the (R)-monoacid ent-8a.

  20. Porous calcium phosphate-poly (lactic-co-glycolic) acid composite bone cement: A viable tunable drug delivery system.

    Science.gov (United States)

    Roy, Abhijit; Jhunjhunwala, Siddharth; Bayer, Emily; Fedorchak, Morgan; Little, Steve R; Kumta, Prashant N

    2016-02-01

    Calcium phosphate based cements (CPCs) are frequently used as bone void fillers for non-load bearing segmental bone defects due to their clinically relevant handling characteristics and ability to promote natural bone growth. Macroporous CPC scaffolds with interconnected pores are preferred for their ability to degrade faster and enable accelerated bone regeneration. Herein, a composite CPC scaffold is developed using newly developed resorbable calcium phosphate cement (ReCaPP) formulation containing degradable microspheres of bio-compatible poly (lactic-co-glycolic acid) (PLGA) serving as porogen. The present study is aimed at characterizing the effect of in-vitro degradation of PLGA microspheres on the physical, chemical and structural characteristics of the composite cements. The porosity measurements results reveal the formation of highly interconnected macroporous scaffolds after degradation of PLGA microspheres. The in-vitro characterizations also suggest that the degradation by products of PLGA reduces the pH of the local environment thereby increasing the dissolution rate of the cement. In addition, the in-vitro vancomycin release from the composite CPC scaffold suggests that the drug association with the composite scaffolds can be tuned to achieve control release kinetics. Further, the study demonstrates control release lasting for longer than 10weeks from the composite cements in which vancomycin is encapsulated in PLGA microspheres.

  1. Effects of lactic acid and glycolic acid on human osteoblasts: a way to understand PLGA involvement in PLGA/calcium phosphate composite failure.

    Science.gov (United States)

    Meyer, Florent; Wardale, John; Best, Serena; Cameron, Ruth; Rushton, Neil; Brooks, Roger

    2012-06-01

    The use of degradable composite materials in orthopedics remains a field of intense research due to their ability to support new bone formation and degrade in a controlled manner, broadening their use for orthopedic applications. Poly (lactide-co-glycolide) acid (PLGA), a degradable biopolymer, is now a popular material for different orthopedic applications and is proposed for use in tissue engineering scaffolds either alone or combined with bioactive ceramics. Interference screws composed of calcium phosphates and PLGA are readily available in the market. However, some reports highlight problems of screw migration or aseptic cyst formation following screw degradation. In order to understand these phenomena and to help to improve implant formulation, we have evaluated the effects of PLGA degradation products: lactic acid and glycolic acid on human osteoblasts in vitro. Cell proliferation, differentiation, and matrix mineralization, important for bone healing were studied. It was found that the toxicity of polymer degradation products under buffering conditions was limited to high concentrations. However, non-toxic concentrations led to a decrease in cell proliferation, rapid cell differentiation, and mineralization failure. Calcium, whilst stimulating cell proliferation was not able to overcome the negative effects of high concentrations of lactic and glycolic acids on osteoblasts. These effects help to explain recently reported clinical failures of calcium phosphate/PLGA composites, but further in vitro analyses are needed to mimic the dynamic situation which occurs in the body by, for example, culture of osteoblasts with materials that have been pre-degraded to different extents and thus be able to relate these findings to the degradation studies that have been performed previously.

  2. Correlation of biological value of feed phosphates with their solubility in water, dilute hydrogen chloride, dilute citric acid, and neutral ammonium citrate.

    Science.gov (United States)

    Sullivan, T W; Douglas, J H; Gonzalez, N J; Bond, P L

    1992-12-01

    Relative biological values (BV) of 36 feed phosphates were determined with female turkeys in bioassays of 21-day duration using three response criteria: weight gain, tibia ash percentage, and gain:feed ratio. Calcium phosphate, dibasic dihydrate (United States Pharmacopeia) was the reference standard. Nine mono-dicalcium phosphates (M-DCP, 21.0% phosphorus), 13 di-monocalcium phosphates (D-MCP, 18.5% phosphorus), and 14 defluorinated phosphates (DFP, 18.0% phosphorus) were evaluated. The average relative BV for M-DCP, D-MCP, and DFP samples were 97.6, 94.6, and 90.8%, respectively. Solubility of phosphates was determined by four recognized methods. The solvents were water, .4% HCl, 2.0% citric acid (CA), and neutral ammonium citrate (NAC). Water solubility of M-DCP samples was greater (67.5%) than that of D-MCP (38.8%) and DFP (8.9%) samples. Correlation of water solubility of phosphates to their relative BV was quite low, and water solubility was a poor indicator of BV. When .4% HCl was the solvent, correlation coefficients (r) were .55, .33, and .72 for M-DCP, D-MCP, and DFP, respectively. Based on these results and prediction equations, .4% HCl solubility would be inappropriate for estimating BV of M-DCP and D-MCP samples. Solubility of feed phosphates (mainly D-MCP and DFP) in 2.0% CA or NAC was positively correlated with BV; the r values were .87 to .95. Both of these solubility tests provided a good index of BV. However, it would seem inappropriate and risky to replace bioassays totally with these tests. Feed phosphate users could perform either the 2.0% CA or NAC solubility test easily as a screen for BV along with other quality control procedures (i.e., phosphorus, calcium, sodium, and fluoride determinations).

  3. Microwave-assisted reaction of peptide formation by amino acid with phosphate: Exploration of the most possible channels for the origin of life

    Institute of Scientific and Technical Information of China (English)

    HU Rong; TIAN Jinping; YIN Yingwu

    2006-01-01

    Microwave-assisted reaction of peptide formation by amino acids with phosphate was studied. The results showed that the products were a mixture of peptides containing dipeptide, octapeptides and cyclic peptides, which could be obtained in a short time. Polyphosphate was also produced synchronously by the intermolecular condensation of phosphate. The polymerization degree reached 99% (pyrophosphate 64%, trimetaphosphate 35%) after 2 h at 200℃ under microwave irradiation. The intermediates of the mixed anhydrides formed by the intermolecular condensation of phosphates and glycin were determined by ESI-MS. Peptides were also produced by the reaction of amino acids with trimetaphosphate in aqueous solution. The conversion degree of valine reached 46.5% even at room temperature. The cyclic process of peptide formation and phosphate polymerization, regeneration and utilization in amino acids-phosphate system under microwave irradiation was detected and proved. Peptides could be continually formed only by inputting energy into this system. The above recycle may be the most possible process for primitive peptide formation in the origin of life.

  4. Natural and pyrogenic humic acids at goethite and natural oxide surfaces interacting with phosphate

    NARCIS (Netherlands)

    Hiemstra, T.; Mia, S.; Duhaut, P.B.; Molleman, B.

    2013-01-01

    Fulvic and humic acids have a large variability in binding to metal (hydr) oxide surfaces and interact differently with oxyanions, as examined here experimentally. Pyrogenic humic acid has been included in our study since it will be released to the environment in the case of large-scale application

  5. New concept bioceramics composed of octacalcium phosphate (OCP) and dicarboxylic acid-intercalated OCP via hydrothermal hot-pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Shiho [Graduate School of Engineering, Osaka Prefecture University (Japan); Matsumoto, Takuya [Graduate School of Dentistry, Osaka University (Japan); Onoki, Takamasa, E-mail: onoki@mtr.osakafu-u.ac.jp [Graduate School of Engineering, Osaka Prefecture University (Japan); Sohmura, Taiji [Graduate School of Dentistry, Osaka University (Japan); Nakahira, Atsushi [Graduate School of Engineering, Osaka Prefecture University (Japan)

    2009-08-01

    Octacalcium phosphate (OCP) and adipic acid-intercalated complexed OCP (Adi-OCP) were synthesized. Moreover, we made ceramic bodies out of them through a hydrothermal hot-pressing (HHP) method. Characteristic features of both the powder and ceramics were investigated by the X-ray diffraction method (XRD). Surface morphology of the ceramics was observed by scanning electron microscopy (SEM). Density, compressive strength and pore size distribution of the ceramics were measured. Crystalline structure of the newly developed OCP ceramics had no phase transformation from the starting materials. Moreover, the newly developed OCP ceramics had good mechanical properties only through the HHP treatment with a temperature as low as 110 deg. C. In order to evaluate bioactivity, the ceramics were immersed in simulating body fluid (SBF). It was predicted that OCP and Adi-OCP had better bioactivity than that of conventional HAp ceramics.

  6. Synthesization and characterization of poly(lactic-co-glycolic acid) / calcium phosphate bone cement from crab shells

    Science.gov (United States)

    Hanan, M. R. Abdul; Daud, N. M.; Ismail, L. H.; Saidin, S.

    2017-05-01

    An injectable calcium phosphate (CaP) bone cement has been widely used for musculoskeletal and bone disorder due to its biocompatible and osteoconductive properties. In this study, CaP was successfully synthesized from crab shells by a wet chemical route. Poly(lactic-co-glycolic acid) (PLGA) microspheres which have been produced through a double emulsion technique were incorporated into the CaP mixture for the purpose of bone cement solidification. The ratio of both compounds, CaP and PLGA, were set at 8:2. The CaP and PLGA/CaP bone cement were analyzed by ATR-FTIR, FESEM-EDX and contact angle analyses. The bone cement was composed of CaP and PLGA where the micro-powders of CaP were agglomerated on the PLGA microspheres. Addition of the PLGA has increased the hydrophilicity of the bone cement which will be beneficial for materials degradation and bone integration.

  7. Structural and dynamical studies of acid-mediated conversion in amorphous-calcium-phosphate based dental composites.

    Science.gov (United States)

    Zhang, Fan; Allen, Andrew J; Levine, Lyle E; Vaudin, Mark D; Skrtic, Drago; Antonucci, Joseph M; Hoffman, Kathleen M; Giuseppetti, Anthony A; Ilavsky, Jan

    2014-10-01

    To investigate the complex structural and dynamical conversion process of the amorphous-calcium-phosphate (ACP)-to-apatite transition in ACP based dental composite materials. Composite disks were prepared using zirconia hybridized ACP fillers (0.4 mass fraction) and photo-activated Bis-GMA/TEGDMA resin (0.6 mass fraction). We performed an investigation of the solution-mediated ACP-to-apatite conversion mechanism in controlled acidic aqueous environment with in situ ultra-small angle X-ray scattering based coherent X-ray photon correlation spectroscopy and ex situ X-ray diffraction, as well as other complementary techniques. We established that the ACP-to-apatite conversion in ACP composites is a two-step process, owing to the sensitivity to local structural changes provided by coherent X-rays. Initially, ACP undergoes a local microstructural rearrangement without losing its amorphous character. We established the catalytic role of the acid and found the time scale of this rearrangement strongly depends on the pH of the solution, which agrees with previous findings about ACP without the polymer matrix being present. In the second step, ACP is converted to an apatitic form with the crystallinity of the formed crystallites being poor. Separately, we also confirmed that in the regular Zr-modified ACP the rate of ACP conversion to hydroxyapatite is slowed significantly compared to unmodified ACP, which is beneficial for targeted slow release of functional calcium and phosphate ions from dental composite materials. For the first time, we were able to follow the complete solution-mediated transition process from ACP to apatite in this class of dental composites in a controlled aqueous environment. A two-step process, suggested previously, was conclusively identified. Copyright © 2014 Academy of Dental Materials. All rights reserved.

  8. Investigation of extraction fraction in confined impinging jet reactors for tri-butyl-phosphate extracting butyric acid process☆

    Institute of Scientific and Technical Information of China (English)

    Zhengming Gao; Manting Zhao; Yun Yu; Zhipeng Li; Jing Han

    2016-01-01

    The extraction fraction E and overall volumetric mass transfer coefficient kLa of TBP extracting butyric acid pro-cess in confined impinging jet reactors (CIJR) with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate (TBP) and butyric acid, the impinging velocity V, the impinging velocity ratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging ve-locity V, the concentration of TBP Corg, and the impinging velocity ratio Vorg/Vaq. However, E and kLa decrease with an increase of the inner diameter di from 1 to 2 mm, the concentration of butyric acid Caq from 0.5%(v/v) to 2%(v/v). The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer performance of CIJR in the extraction operation.

  9. A pulse radiolysis investigation of the reactions of tributyl phosphate with the radical products of aqueous nitric acid irradiation.

    Science.gov (United States)

    Mincher, Bruce J; Mezyk, Stephen P; Martin, Leigh R

    2008-07-17

    Tributyl phosphate (TBP) is the most common organic compound used in liquid-liquid separations for the recovery of uranium, neptunium, and plutonium from acidic nuclear fuel dissolutions. The goal of these processes is to extract the actinides while leaving fission products in the acidic, aqueous phase. However, the radiolytic degradation of TBP has been shown to reduce separation factors of the actinides from fission products and to impede the back-extraction of the actinides during stripping. As most previous investigations of the radiation chemistry of TBP have focused on steady state radiolysis and stable product identification, with dibutylphosphoric acid (HDBP) invariably being the major product, here we have determined room temperature rate constants for the reactions of TBP and HDBP with the hydroxyl radical [(5.00 +/- 0.05) x 10(9), (4.40 +/- 0.13) x 10(9) M(-1) s(-1)], hydrogen atom [(1.8 +/-0.2) x 10(8), (1.1 +/- 0.1) x 10(8) M(-1) s(-1)], nitrate radical [(4.3 +/- 0.7) x 10(6), (2.9 +/- 0.2) x 10(6) M(-1) s(-1)], and nitrite radical (<2 x 10 (5), <2 x 10(5) M(-1) s(-1)), respectively. These data are used to discuss the mechanism of TBP radical-induced degradation.

  10. Triose phosphate isomerase from the coelacanth. An approach to the rapid determination of an amino acid sequence with small amounts of material.

    Science.gov (United States)

    Kolb, E; Harris, J I; Bridgen, J

    1974-02-01

    The preparation and purification of cyanogen bromide fragments from [(14)C]carboxymethylated coelacanth triose phosphate isomerase is presented. The automated sequencing of these fragments, the lysine-blocked tryptic peptides derived from them, and also of the intact protein, is described. Combination with results from manual sequence analysis has given the 247-residue amino acid sequence of coelacanth triose phosphate isomerase in 4 months, by using 100mg of enzyme. (Two small adjacent peptides were placed by homology with the rabbit enzyme.) Comparison of this sequence with that of the rabbit muscle enzyme shows that 207 (84%) of the residues are identical. This slow rate of evolutionary change (corresponding to two amino acid substitutions per 100 residues per 100 million years) is similar to that found for glyceraldehyde 3-phosphate dehydrogenase. The reliability of sequence information obtained by automated methods is discussed.

  11. Fe2+ and Cu2+ increase the production of hyaluronic acid by lactobacilli via affecting different stages of the pentose phosphate pathway.

    Science.gov (United States)

    Choi, Sy-Bing; Lew, Lee-Ching; Hor, Kok-Chiu; Liong, Min-Tze

    2014-05-01

    This study aimed at optimizing the production of hyaluronic acid by Lactobacillus acidophilus FTDC 1231 using response surface methodology and evaluating the effects of divalent metal ions along the production pathway using molecular docking. Among different divalent metal ions that were screened, only iron (II) sulphate and copper (II) sulphate significantly (P pentose phosphate pathway.

  12. Controlled release of rhBMP-2 loaded poly(dl-lactic-co-glycolic acid)/calcium phosphate cement composites in vivo.

    NARCIS (Netherlands)

    Ruhe, P.Q.; Boerman, O.C.; Russel, F.G.M.; Spauwen, P.H.M.; Mikos, A.G.; Jansen, J.A.

    2005-01-01

    The release kinetics of recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded poly(dl-lactic-co-glycolic acid)/calcium phosphate cement (PLGA/Ca-P cement) composites were studied in vivo. RhBMP-2 was radiolabeled with (131)I and entrapped within PLGA microparticles or adsorbed onto the

  13. Electrolytic deposition of calcium phosphate/chitosan coating on titanium alloy: Growth kinetics and influence of current density, acetic acid, and chitosan

    NARCIS (Netherlands)

    Wang, Jiawei; Apeldoorn, van Aart; Groot, de Klaas

    2006-01-01

    Electrolytically deposited calcium phosphate/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning ele

  14. A boron phosphate-phosphoric acid composite membrane for medium temperature proton exchange membrane fuel cells

    Science.gov (United States)

    Mamlouk, M.; Scott, K.

    2015-07-01

    A composite membrane based on a non-stoichiometric composition of BPO4 with excess of PO4 (BPOx) was synthesised and characterised for medium temperature fuel cell use (120-180 °C). The electrolyte was characterised by FTIR, SS-NMR, TGA and XRD and showed that the B-O is tetrahedral, in agreement with reports in the literature that boron phosphorus oxide compounds at B:P < 1 are exclusively built of borate and phosphate tetrahedra. Platinum micro electrodes were used to study the electrolyte compatibility and stability towards oxygen reduction at 150 °C and to obtain kinetic and mass transport parameters. The conductivities of the pure BPOx membrane electrolyte and a Polybenzimidazole (PBI)-4BPOx composite membrane were 7.9 × 10-2 S cm-1 and 4.5 × 10-2 S cm-1 respectively at 150 °C, 5%RH. Fuel cell tests showed a significant enhancement in performance of BPOx over that of typical 5.6H3PO4-PBI membrane electrolyte. The enhancement is due to the improved ionic conductivity (3×), a higher exchange current density of the oxygen reduction (30×) and a lower membrane gas permeability (10×). Fuel cell current densities at 0.6 V were 706 and 425 mA cm-2 for BPOx and 5.6H3PO4-PBI, respectively, at 150 °C with O2 (atm).

  15. Glycerol-3-phosphate Acyltransferase Isoform-4 (GPAT4) Limits Oxidation of Exogenous Fatty Acids in Brown Adipocytes.

    Science.gov (United States)

    Cooper, Daniel E; Grevengoed, Trisha J; Klett, Eric L; Coleman, Rosalind A

    2015-06-12

    Glycerol-3-phosphate acyltransferase-4 (GPAT4) null pups grew poorly during the suckling period and, as adults, were protected from high fat diet-induced obesity. To determine why Gpat4(-/-) mice failed to gain weight during these two periods of high fat feeding, we examined energy metabolism. Compared with controls, the metabolic rate of Gpat4(-/-) mice fed a 45% fat diet was 12% higher. Core body temperature was 1 ºC higher after high fat feeding. Food intake, fat absorption, and activity were similar in both genotypes. Impaired weight gain in Gpat4(-/-) mice did not result from increased heat loss, because both cold tolerance and response to a β3-adrenergic agonist were similar in both genotypes. Because GPAT4 comprises 65% of the total GPAT activity in brown adipose tissue (BAT), we characterized BAT function. A 45% fat diet increased the Gpat4(-/-) BAT expression of peroxisome proliferator-activated receptor α (PPAR) target genes, Cpt1α, Pgc1α, and Ucp1, and BAT mitochondria oxidized oleate and pyruvate at higher rates than controls, suggesting that fatty acid signaling and flux through the TCA cycle were enhanced. To assess the role of GPAT4 directly, neonatal BAT preadipocytes were differentiated to adipocytes. Compared with controls, Gpat4(-/-) brown adipocytes incorporated 33% less fatty acid into triacylglycerol and 46% more into the pathway of β-oxidation. The increased oxidation rate was due solely to an increase in the oxidation of exogenous fatty acids. These data suggest that in the absence of cold exposure, GPAT4 limits excessive fatty acid oxidation and the detrimental induction of a hypermetabolic state.

  16. Second trimester amniotic fluid glucose, uric acid, phosphate, potassium, and sodium concentrations in relation to maternal pre-pregnancy BMI and birth weight centiles.

    Science.gov (United States)

    Fotiou, Maria; Michaelidou, Alexandra Maria; Athanasiadis, Apostolos P; Menexes, Georgios; Symeonidou, Maria; Koulourida, Vasiliki; Ganidou, Maria; Theodoridis, Theodoros D; Tarlatzis, Basil C

    2015-05-01

    To study the evolution profile of amniotic fluid (AF) glucose, uric acid, phosphate, potassium, and sodium, in the second trimester of pregnancy, and explore the possible relations between the concentration of these components and maternal, as well as neonatal characteristics. AF of 52 pregnant women was analyzed using an automatic multichannel analyzer. Maternal age, pre-pregnancy Body Mass Index (BMI), inter-pregnancy intervals, and smoking status were derived from questionnaires. Information on pregnancy and delivery was collected from medical records. Uric acid increased (r = 0.423, p uric acid concentration (r = 0.460, p uric acid and phosphate levels were significantly related to birth weight centiles (R(2)( )= 0.345, p uric acid concentration, and (c) in appropriate for gestational age infants, AF phosphate and uric acid levels may serve as potential biomarkers of birth weight centiles. Further studies on AF composition may help to unravel the biochemical pathways underlying fetal development and could offer insight on the potential impact of maternal nutritional management on fetal growth regulation.

  17. Organic acid production and plant growth promotion as a function of phosphate solubilization by Acinetobacter rhizosphaerae strain BIHB 723 isolated from the cold deserts of the trans-Himalayas.

    Science.gov (United States)

    Gulati, Arvind; Sharma, Natasha; Vyas, Pratibha; Sood, Swati; Rahi, Praveen; Pathania, Vijaylata; Prasad, Ramdeen

    2010-11-01

    An efficient phosphate-solubilizing plant growth-promoting Acinetobacter rhizosphaerae strain BIHB 723 exhibited significantly higher solubilization of tricalcium phosphate (TCP) than Udaipur rock phosphate (URP), Mussoorie rock phosphate (MRP) and North Carolina rock phosphate (NCRP). Qualitative and quantitative differences were discerned in the gluconic, oxalic, 2-keto gluconic, lactic, malic and formic acids during the solubilization of various inorganic phosphates by the strain. Gluconic acid was the main organic acid produced during phosphate solubilization. Formic acid production was restricted to TCP solubilization and oxalic acid production to the solubilization of MRP, URP and NCRP. A significant increase in plant height, shoot fresh weight, shoot dry weight, root length, root dry weight, and root, shoot and soil phosphorus (P) contents was recorded with the inoculated treatments over the uninoculated NP(0)K or NP(TCP)K treatments. Plant growth promotion as a function of phosphate solubilization suggested that the use of bacterial strain would be a beneficial addition to the agriculture practices in TCP-rich soils in reducing the application of phosphatic fertilizers.

  18. Improvement of glyphosate resistance through concurrent mutations in three amino acids of the Ochrobactrum 5-enopyruvylshikimate-3-phosphate synthase.

    Science.gov (United States)

    Tian, Yong-Sheng; Xu, Jing; Xiong, Ai-Sheng; Zhao, Wei; Fu, Xiao-Yan; Peng, Ri-He; Yao, Quan-Hong

    2011-12-01

    A mutant of 5-enopyruvylshikimate-3-phosphate synthase from Ochrobactrum anthropi was identified after four rounds of DNA shuffling and screening. Its ability to restore the growth of the mutant ER2799 cell on an M9 minimal medium containing 300 mM glyphosate led to its identification. The mutant had mutations in seven amino acids: E145G, N163H, N267S, P318R, M377V, M425T, and P438L. Among these mutations, N267S, P318R, and M425T have never been previously reported as important residues for glyphosate resistance. However, in the present study they were found by site-directed mutagenesis to collectively contribute to the improvement of glyphosate tolerance. Kinetic analyses of these three mutants demonstrated that the effectiveness of these three individual amino acid alterations on glyphosate tolerance was in the order P318R > M425T > N267S. The results of the kinetic analyses combined with a three-dimensional structure modeling of the location of P318R and M425T demonstrate that the lower hemisphere's upper surface is possibly another important region for glyphosate resistance. Furthermore, the transgenic Arabidopsis was obtained to confirm the potential of the mutant in developing glyphosate-resistant crops.

  19. Improvement of Glyphosate Resistance through Concurrent Mutations in Three Amino Acids of the Ochrobactrum 5-Enopyruvylshikimate-3-Phosphate Synthase ▿

    Science.gov (United States)

    Tian, Yong-Sheng; Xu, Jing; Xiong, Ai-Sheng; Zhao, Wei; Fu, Xiao-Yan; Peng, Ri-He; Yao, Quan-Hong

    2011-01-01

    A mutant of 5-enopyruvylshikimate-3-phosphate synthase from Ochrobactrum anthropi was identified after four rounds of DNA shuffling and screening. Its ability to restore the growth of the mutant ER2799 cell on an M9 minimal medium containing 300 mM glyphosate led to its identification. The mutant had mutations in seven amino acids: E145G, N163H, N267S, P318R, M377V, M425T, and P438L. Among these mutations, N267S, P318R, and M425T have never been previously reported as important residues for glyphosate resistance. However, in the present study they were found by site-directed mutagenesis to collectively contribute to the improvement of glyphosate tolerance. Kinetic analyses of these three mutants demonstrated that the effectiveness of these three individual amino acid alterations on glyphosate tolerance was in the order P318R > M425T > N267S. The results of the kinetic analyses combined with a three-dimensional structure modeling of the location of P318R and M425T demonstrate that the lower hemisphere's upper surface is possibly another important region for glyphosate resistance. Furthermore, the transgenic Arabidopsis was obtained to confirm the potential of the mutant in developing glyphosate-resistant crops. PMID:21948846

  20. Enhanced integrin-mediated human osteoblastic adhesion to porous amorphous calcium phosphate/poly(L-lactic acid) composite

    Institute of Scientific and Technical Information of China (English)

    Huang Xin; Qi Yiying; Li Weixu; Shi Zhongli; Weng Wenjian; Chen Kui; He Rongxin

    2014-01-01

    Background The initial osteoblastic adhesion to materials characterizes the first phase of cell-material interactions and influences all the events leading to the formation of new bone.In a previous work,we developed a novel amorphous calcium phosphate (ACP)/poly(L-lactic acid) (PLLA) material that demonstrated morphologic variations in its microstructure.The aim of this study was to investigate the initial interaction between this material and osteoblastic cells.Cellular attachment and the corresponding signal transduction pathways were investigated.Methods A porous ACP/PLLA composite and PLLA scaffold (as a control) were incubated in fetal bovine serum (FBS) containing phosphate-buffered saline (PBS),and the protein adsorption was determined.Osteoblastic MG63 cells were seeded on the materials and cultured for 1,4,8,or 24 hours.Cell attachment was evaluated using the MTS method.Cell morphology was examined using scanning electron microscopy (SEM).The expression levels of the genes encoding integrin subunits α1,α5,αv,β1,focal adhesion kinase (FAK),and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were determined using real-time reverse transcription polymerase chain reaction (RT-PCR).Results The ACP/PLLA material significantly increased the protein adsorption by 6.4-fold at 1 hour and 2.4-fold at 24 hours,compared with the pure PLLA scaffold.The attachment of osteoblastic cells to the ACP/PLLA was significantly higher than that on the PLLA scaffold.The SEM observation revealed a polygonal spread shape of cells on the ACP/ PLLA,with the filopodia adhered to the scaffold surface.In contrast,the calls on the PLLA scaffold exhibited a spherical or polygonal morphology.Additionally,real-time RT-PCR showed that the genes encoding the integrin subunits α1,αv,β1,and FAK were expressed at higher levels on the ACP/PLLA composite.Conclusions The ACP/PLLA composite promoted protein adsorption and osteoblastic adhesion.The enhanced cell adhesion may be mediated by

  1. Phytic acid and inorganic phosphate composition in soybean lines with independent IPK1 mutations

    Science.gov (United States)

    Soybean [Glycine max (L.) Merr] seeds contain a large amount of phosphorus (P), which is stored as phytic acid (PA). PA is indigestible by nonruminent livestock and considered an anti-nutritional factor because PA chelates divalent cations and prevents the uptake of essential nutrients. Interest in...

  2. The influence of tributyl phosphate on molybdenum extraction with solutions of dibutyl phosphoric acid

    Science.gov (United States)

    Goletskiy, N. D.; Zilberman, B. Ya.; Fedorov, Yu. S.; Khonina, I. V.; Kukharev, D. N.

    2006-01-01

    Comparative investigations were carried out to study the influence of TBP on Mo extraction by HDBP solutions in xylene and TBP in xylene. The dependences of DMo on HNO3 concentration for both HDBP and D2EHPA have minima at about 3 mol/L HNO3. This shows similar extraction properties of HDBP and D2EHPA. The presence of TBP in the solvent results in the reduction of Mo extraction and in an increase in the formal slopes of the falling and rising parts of the logDMo — log[HNO3] curve from -0.5 and +2 up to -2 and +4. Solvent loading curves with Mo show that in the absence of TBP a molybdenum solvate with two molecules of HDBP is formed at low acidity. Anomalous increase in the maximum solvent loading in the presence of TBP is caused by the ability of TBP to extract Mo from oversaturated low acidity solutions following the acidic mechanism. A molybdenum solvate with two HDBP molecules and one HNO3 molecule is possibly formed at high acidity. A flowsheet for Mo recovery from HLW with HDBP-TBP solvent was tested in centrifugal contactors.

  3. How phosphoinositide 3-phosphate controls growth downstream of amino acids and autophagy downstream of amino acid withdrawal.

    Science.gov (United States)

    Ktistakis, Nicholas T; Manifava, Maria; Schoenfelder, Priya; Rotondo, Sergio

    2012-02-01

    The simple phosphoinositide PtdIns3P has been shown to control cell growth downstream of amino acid signalling and autophagy downstream of amino acid withdrawal. These opposing effects depend in part on the existence of distinct complexes of Vps34 (vacuolar protein sorting 34), the kinase responsible for the majority of PtdIns3P synthesis in cells: one complex is activated after amino acid withdrawal to induce autophagy and another regulates mTORC1 (mammalian target of rapamycin complex 1) activation when amino acids are present. However, lipid-dependent signalling almost always exhibits a spatial dimension, related to the site of formation of the lipid signal. In the case of PtdIns3P-regulated autophagy induction, recent data suggest that PtdIns3P accumulates in a membrane compartment dynamically connected to the endoplasmic reticulum that constitutes a platform for the formation of some autophagosomes. For PtdIns3P-regulated mTORC1 activity, a spatial context is not yet known: several possibilities can be envisaged based on the known effects of PtdIns3P on the endocytic system and on recent data suggesting that activation of mTORC1 depends on its localization on lysosomes.

  4. Role of phosphate and Fe-oxides on the acid-aided extraction efficiency and readsorption of As in field-aged soil.

    Science.gov (United States)

    Im, Jinwoo; Yang, Kyung; Moon, Seheum; Kim, Young-Jin; Nam, Kyoungphile

    2015-12-30

    This study was conducted to investigate arsenic (As) readsorption phenomenon in acid-treated soil using phosphate as a competing ion. Three field-aged soils (i.e., S1, paddy soil; S2, field soil; S3, forest soil) originally contaminated with As ranging from 30 to 59 mg/kg-soil were collected from a former smelter site. When 0.2M hydrochloric acid (HCl) alone was used as an extraction solution, As bound to iron (Fe) oxides was removed but significant amount of the released As was readsorbed onto residual Fe-oxides, yielding low As extraction efficiency of 11-27%. Readsorption of the released As seemed to occur preferentially on amorphous Fe-oxides. In contrast, As extraction efficiency was greatly increased by 0.2M HCl solution supplemented with monopotassium phosphate (KH2PO4), which was greatly influenced by the molar ratio of acid to phosphate. In addition, by the extraction solution with an optimal ratio of 0.2M HCl/0.1M KH2PO4, As extraction efficiency differed with soil types, showing 79.6, 44.1, and 61.0% in S1, S2, and S3, respectively. The reason can be ascribed to the blocking of the available As readsorption sites by phosphate ions, the sites seemed to mainly reside on the residual amorphous Fe-oxides in soil. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Mesoporous siliconiobium phosphate as a pure Brønsted acid catalyst with excellent performance for the dehydration of glycerol to acrolein.

    Science.gov (United States)

    Choi, Youngbo; Park, Dae Sung; Yun, Hyeong Jin; Baek, Jayeon; Yun, Danim; Yi, Jongheop

    2012-12-01

    The development of solid acid catalysts that contain a high density of Brønsted acid sites with suitable acidity, as well as a long lifetime, is one of great challenges for the efficient dehydration of glycerol to acrolein. Herein, we report on a mesoporous siliconiobium phosphate (NbPSi-0.5) composite, which is a promising solid Brønsted acid that is a potential candidate for such a high-performance catalyst. A variety of characterization results confirm that NbPSi-0.5 contains nearly pure Brønsted acid sites and has well-defined large mesopores. In addition, NbPSi-0.5 contains a similar amount of acid sites and exhibits weaker acidity than that of the highly acidic niobium phosphate and HZSM-5 zeolite. NbPSi-0.5 is quite stable and has a high activity for the dehydration of glycerol. The stability of NbPSi-0.5 is about three times higher than that of the reported catalyst. The significantly enhanced catalytic performance of NbPSi-0.5 can be attributed to 1) nearly pure Brønsted acidity, which suppresses side reactions that lead to coke formation; 2) a significant reduction of pore blocking due to the mesopores; and 3) a decrease in the amount and oxidation temperature of coke.

  6. Application of encapsulation (pH-sensitive polymer and phosphate buffer macrocapsules): a novel approach to remediation of acidic ground water.

    Science.gov (United States)

    Aelion, C Marjorie; Davis, Harley T; Flora, Joseph R V; Kirtland, Brian C; Amidon, Mark B

    2009-01-01

    Macrocapsules, composed of a pH-sensitive polymer and phosphate buffer, offer a novel remediation alternative for acidic ground waters. To test their potential effectiveness, laboratory experiments were carried out followed by a field trial within a coal pile runoff (CPR) acidic contaminant plume. Results of traditional limestone and macrocapsule treatments were compared in both laboratory and field experiments. Macrocapsules were more effective than limestone as a passive treatment for raising pH in well water from 2.5 to 6 in both laboratory and field experiments. The limestone treatments had limited impact on pH, only increasing pH as high as 3.3, and armoring by iron was evident in the field trial. Aluminum, iron and sulfate concentrations remained relatively constant throughout the experiments, but phosphate increased (0.15-32 mg/L), indicating macrocapsule release. This research confirmed that macrocapsules may be an effective alternative to limestone to treat highly acidic ground water.

  7. Metal-phosphate binders

    Science.gov (United States)

    Howe, Beth Ann [Lewistown, IL; Chaps-Cabrera, Jesus Guadalupe [Coahuila, MX

    2009-05-12

    A metal-phosphate binder is provided. The binder may include an aqueous phosphoric acid solution, a metal-cation donor including a metal other than aluminum, an aluminum-cation donor, and a non-carbohydrate electron donor.

  8. Zirconium phosphate nanoparticles as a remarkable solid acid catalyst for selective solvent-free alkylation of phenol

    Institute of Scientific and Technical Information of China (English)

    Abdol R. Hajipour; Hirbod Karimi

    2014-01-01

    A facile synthesis of α-zirconium phosphate (ZP) nanoparticles as an effective, eco-friendly, and recyclable solid acid catalyst is reported. Polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) were used as organic matrix as dispersing agents and served as a template for the nanoparticles. Hydrogen bonds between ZP and PVA or PVP, along the polymer chains, appear to play an im-portant role for improving the dispersion of in situ formed ZP. Following calcination of PVA/ZP or PVP/ZP, pure hexagonal ZP nanoparticles were obtained. The catalysts were characterized by ni-trogen sorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, Fouri-er transform infrared spectroscopy (FTIR), scanning electron microscopy, and transmission elec-tron microscopy. Pyridine-FTIR and temperature-programmed desorption of NH3 suggest the presence of Brönsted acid sites. The acidic properties of the catalyst were studied in Friedel-Crafts alkylation of phenol by tert-butanol, producing 2-tert-butylphenol, 4-tert-butylphenol, and 2,4-di-tert-butylphenol. The alkylation reaction was performed in the presence of catalysts P2O5/Al2O3, P2O5/SiO2, α-ZrP (prepared in the absence of the polymers), and various ionic liquids. The use of the hexagonal ZP nanoparticle catalyst afforded an excellent phenol conversion (86%) and selectivity towards 4-tert-butylphenol (83%) under optimized reaction conditions. The catalyst was easily recovered from the reaction mixture, regenerated, and reused at least four times without significant loss in the catalytic activity.

  9. Degradation and osteogenic potential of a novel poly(lactic acid/nano-sized β-tricalcium phosphate scaffold

    Directory of Open Access Journals (Sweden)

    Cao L

    2012-11-01

    Full Text Available Lu Cao,1,2 Ping-Guo Duan,1,2 Hui-Ren Wang,1,2 Xi-Lei Li,1,2 Feng-Lai Yuan,3 Zhong-Yong Fan,4 Su-Ming Li,5 Jian Dong1,21Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China; 2State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, China; 3Affiliated Third Hospital of Nantong University, Wuxi, Jiangsu, China; 4Department of Materials Science, Fudan University, Shanghai, China; 5Max Mousseron Institute on Biomolecules, Montpellier I University, Montpellier, FranceAbstract: The purpose of this study was to investigate the influence of nano-sized β-tricalcium phosphate (β-TCP on the biological performance of poly (lactic acid (PLA composite scaffolds by using in vitro degradation and an in vivo model of heterotopic bone formation. Nano-sized βTCP (nβ-TCP was prepared with a wet grinding method from micro-sized β-TCP (mβ-TCP, and composite scaffolds containing 0, 10, 30, or 50 wt% nβ-TCP or 30 wt% mβ -TCP were generated using a freeze-drying method. Degradation was assessed by monitoring changes in microstructure, pH, weight, and compressive strength over a 26-week period of hydrolysis. Composite scaffolds were processed into blocks, and implanted into muscular pockets of rabbits after loading with recombinant human bone morphogenetic protein-2 (rhBMP-2. New bone formation was evaluated based on histological and immunohistochemical analysis 2, 4, and 8 weeks after implantation. The in vitro results indicated that the buffering effect of nβ-TCP was stronger than mβ-TCP, which was positively correlated with the content of nβ-TCP. The in vivo findings demonstrated that nβ-TCP enhanced the osteoconductivity of the scaffolds. Although composite scaffolds containing 30% nβ-TCP exhibited similar osteoconductivity to 50% nβ-TCP, they had better mechanical properties than the 50% nβ-TCP scaffolds. This study supports the potential application of a composite scaffold containing 30

  10. Acid-base properties and surface complexation modeling of phosphate anion adsorption by wasted low grade iron ore with high phosphorus.

    Science.gov (United States)

    Yuan, Xiaoli; Bai, Chenguang; Xia, Wentang; An, Juan

    2014-08-15

    The adsorption phenomena and specific reaction processes of phosphate onto wasted low grade iron ore with high phosphorus (WLGIOWHP) were studied in this work. Zeta potential and Fourier transform infrared spectroscopy (FTIR) analyses were used to elucidate the interaction mechanism between WLGIOWHP and aqueous solution. The results implied that the main adsorption mechanism was the replacement of surface hydroxyl groups by phosphate via the formation of inner-sphere complex. The adsorption process was characterized by chemical adsorption onto WLGIOWHP. The non-electrostatic model (NEM) was used to simulate the surface adsorption of phosphate onto WLGIOWHP. The total surface site density and protonation constants for NEM (N(T)=1.6×10(-4) mol/g, K(a1)=2.2×10(-4), K(a2)=6.82×10(-9)) were obtained by non-linear data fitting of acid-base titrations. In addition, the NEM was used to establish the surface adsorption complexation modeling of phosphate onto WLGIOWHP. The model successfully predicted the adsorption of phosphate onto WLGIOWHP from municipal wastewater. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Phosphorus fertility recapitalization of nutrient-depleted tropical acid soils with reactive phosphate rock: An assessment using the isotopic exchange technique

    Energy Technology Data Exchange (ETDEWEB)

    Fardeau, J.-C. [INRA, Departement Environnement et Agronomie, Versailles (France)]. E-mail: fardeau@versailles.inra.fr; Zapata, F. [IAEA, Soil and Water Management and Crop Nutrition Section, Joint FAO/IAEA Programme, Vienna (Austria)

    2002-05-15

    A 'soil P fertility recapitalization' initiative utilizing large rates of phosphate rocks (PRs) was proposed to improve the soil P status and increase the sustainable food production in acid and P-deficient tropical soils. Two series of experiments were carried out using five tropical acid soils treated with heavy applications of Gafsa phosphate rock (GPR). In the first series, the soils were mixed with GPR at the following application rates: 0, 500, 1000 and 2000 mg P{center_dot}kg{sup -1}, and incubated for one month in moist conditions. In another series, 1000 mg P kg{sup -1} applied as GPR was added to three soils and incubated for 1.5 month; thereafter 50 mg P kg{sup -1} as triple superphosphate (TSP) were added. The {sup 32}P isotopic exchange method was utilized to assess the contribution of GPR to the available soil P. Changes in amounts, E, of P transferred with time as phosphate ions from the soil particles to the soil solution as well as changes in pH, calcium and phosphate concentrations in soil suspensions were determined. It was found that: (i) the contribution of P from GPR to recapitalization of soil P fertility was mainly assessed by E pool size, pH, calcium and phosphate concentrations; other variables were not significant at the 0.1 level; (ii) heavy applications of GPR did not saturate all the P sorption sites, P freshly applied as water-soluble P was still sorbed; (iii) recapitalization of soil P fertility using GPR was partly obtained in some acid tropical soils; (iv) Upon dissolution, GPR provided calcium ions to crops and to soils, thus reducing Al toxicity, but its liming effect was limited. To explain these effects with heavy application rates of GPR, it was postulated that a coating of Al and Fe compounds is formed around PR particles with time, thus reducing further dissolution. (author)

  12. Lysophosphatidic acid activates peroxisome proliferator activated receptor-γ in CHO cells that over-express glycerol 3-phosphate acyltransferase-1.

    Directory of Open Access Journals (Sweden)

    Cliona M Stapleton

    Full Text Available Lysophosphatidic acid (LPA is an agonist for peroxisome proliferator activated receptor-γ (PPARγ. Although glycerol-3-phosphate acyltransferase-1 (GPAT1 esterifies glycerol-3-phosphate to form LPA, an intermediate in the de novo synthesis of glycerolipids, it has been assumed that LPA synthesized by this route does not have a signaling role. The availability of Chinese Hamster Ovary (CHO cells that stably overexpress GPAT1, allowed us to analyze PPARγ activation in the presence of LPA produced as an intracellular intermediate. LPA levels in CHO-GPAT1 cells were 6-fold higher than in wild-type CHO cells, and the mRNA abundance of CD36, a PPARγ target, was 2-fold higher. Transactivation assays showed that PPARγ activity was higher in the cells that overexpressed GPAT1. PPARγ activity was enhanced further in CHO-GPAT1 cells treated with the PPARγ ligand troglitazone. Extracellular LPA, phosphatidic acid (PA or a membrane-permeable diacylglycerol had no effect, showing that PPARγ had been activated by LPA generated intracellularly. Transient transfection of a vector expressing 1-acylglycerol-3-phosphate acyltransferase-2, which converts endogenous LPA to PA, markedly reduced PPARγ activity, as did over-expressing diacylglycerol kinase, which converts DAG to PA, indicating that PA could be a potent inhibitor of PPARγ. These data suggest that LPA synthesized via the glycerol-3-phosphate pathway can activate PPARγ and that intermediates of de novo glycerolipid synthesis regulate gene expression.

  13. In Vivo Predictive Dissolution: Comparing the Effect of Bicarbonate and Phosphate Buffer on the Dissolution of Weak Acids and Weak Bases.

    Science.gov (United States)

    Krieg, Brian J; Taghavi, Seyed Mohammad; Amidon, Gordon L; Amidon, Gregory E

    2015-09-01

    Bicarbonate is the main buffer in the small intestine and it is well known that buffer properties such as pKa can affect the dissolution rate of ionizable drugs. However, bicarbonate buffer is complicated to work with experimentally. Finding a suitable substitute for bicarbonate buffer may provide a way to perform more physiologically relevant dissolution tests. The dissolution of weak acid and weak base drugs was conducted in bicarbonate and phosphate buffer using rotating disk dissolution methodology. Experimental results were compared with the predicted results using the film model approach of (Mooney K, Mintun M, Himmelstein K, Stella V. 1981. J Pharm Sci 70(1):22-32) based on equilibrium assumptions as well as a model accounting for the slow hydration reaction, CO2 + H2 O → H2 CO3 . Assuming carbonic acid is irreversible in the dehydration direction: CO2 + H2 O ← H2 CO3 , the transport analysis can accurately predict rotating disk dissolution of weak acid and weak base drugs in bicarbonate buffer. The predictions show that matching the dissolution of weak acid and weak base drugs in phosphate and bicarbonate buffer is possible. The phosphate buffer concentration necessary to match physiologically relevant bicarbonate buffer [e.g., 10.5 mM (HCO3 (-) ), pH = 6.5] is typically in the range of 1-25 mM and is very dependent upon drug solubility and pKa .

  14. Comparison and preparation of multilayered polylactic acid fabric strengthen calcium phosphate-based bone substitutes for orthopedic applications.

    Science.gov (United States)

    Chen, Wen-Cheng; Ko, Chia-Ling; Yang, Jia-Kai; Wu, Hui-Yu; Lin, Jia-Horng

    2016-03-01

    An attempt to maintain the three-dimensional space into restorative sites through the conveniently pack porous fillers are general used strategy. Advancement in the manufacturing protective shells in the scaffolds, which would be filled with brittle ceramic grafts for the development of highly connective pores provides the approach to solve crack problem for generating the tissues. Therefore, multilayered braided and alkalized poly(lactic acid) (PLA) composites with calcium phosphate bone cement (CPC) were synthesized and compared. The PLA/CPC composites were divided into various groups according to a series of heat-treatment temperatures (100-190 °C) and periods (1-3 h) and then characterized. The effects of 24-h immersion on the strength decay resistance of the samples were compared. Results showed that the residual oil capped on the surfaces of alkalized PLA braid was removed, and the structure was unaltered. However, the reduced tensile stress of alkalized PLA braids was due to ester-group formation by hydrolysis. Mechanical test results of PLA/CPC composites showed that the strength significantly increased after heat treatment, except when the heating temperature was higher than the PLA melting point at approximately 160-170 °C. The degree of PLA after recrystallization became higher than that of unheated composites, thereby leading to reduced strength and toughness of the specimen. Braiding fibers of biodegradable PLA reinforced and toughened the structure particularly of the extra-brittle material of thin-sheet CPC after implantation.

  15. Rheological and physical properties of camel and cow milk gels enriched with phosphate and calcium during acid-induced gelation.

    Science.gov (United States)

    Kamal, Mohammad; Foukani, Mohammed; Karoui, Romdhane

    2017-02-01

    The rheological properties of acid-induced coagulation of camel and cow milk gels following the addition of calcium chloride (CaCl2) and hydrogen phosphate dehydrate (Na2HPO4*2H2O) were investigated using a dynamic low amplitude oscillatory rheology. For a considered condition, the final values of storage modulus (G') and loss modulus (G″) of camel milk gels were significantly lower than those of cow milk gels. The increase of the added CaCl2 levels improved significantly the gelation properties of camel and cow milk gels, since a reduction in the gelation time and an increase in the gel firmness were observed. Following the addition of Na2HPO4*2H2O at 10 and 20 mM, no significant effect on the gelation rate and the firmness of camel milk gels was observed, while, a significant decrease in the gelation rate and firmness were observed for cow milk gels.

  16. Hybrid calcium phosphate coatings with the addition of trace elements and polyaspartic acid by a low-thermal process

    Energy Technology Data Exchange (ETDEWEB)

    Xu Sanzhong; Lin Xiangjin [The First Affiliated Hospital, College of Medicine of Zhejiang University, Hangzhou 310003 (China); Yang Xianyan; Chen Xiaoyi; Gao Changyou; Gou Zhongru [Zhejiang-California International NanoSystems Institute, Zhejiang University, Hangzhou 310029 (China); Zhang Lei; Yang Guojing, E-mail: zhrgou@zju.edu.cn [Rui' an People' s Hospital and the 3rd Hospital Affiliated to Wenzhou Medical College, Rui' an 325200 (China)

    2011-06-15

    Research in the field of orthopedic implantology is currently focused on developing methodologies to potentiate osseointegration and to expedite the reestablishment of full functionality. We have developed a simple biomimetic approach for preparing trace elements-codoped calcium phosphate (teCaP) coatings on a titanium substrate. The reaction proceeded via low-thermal incubation in trace elements (TEs)-added simulated body fluid (teSBF) at 90 and 120 deg. C. The x-ray photoelectron spectroscopy, x-ray diffraction and energy-dispersive x-ray analyses demonstrated that the teCaP coating was the composite of hydroxyapatite and whitlockite, simultaneously doped with magnesium, strontium, zinc and silicon. The addition of polyaspartic acid and TEs into SBF significantly densified the coating. The incubation temperature is another important factor controlling the coating precipitation rate and bonding strength. An incubation temperature of 120 deg. C could accelerate the coating precipitation and improve the interface bonding strength. The in vitro cell culture investigation indicated that the teCaP coating supported the adhesion and spreading of ovariectomized rat mesenchymal stem cells (rMSCs) and particularly, promoted rMSCs proliferation compared to the CaP coating prepared in SBF. Collectively, from such a biomimetic route there potentially arises a general procedure to prepare a wide range of bioactive teCaP coatings of different composition for osteoporotic osteogenic cells activation response.

  17. CHARACTERISTICS OF PHOSPHATE ROCK MATERIALS FROM CHINA, INDONESIA AND TUNISIA AND THEIR DISSOLUTION IN INDONESIAN ACID SOILS

    Directory of Open Access Journals (Sweden)

    Yusdar Hilman

    2016-10-01

    Full Text Available Dissolution of phosphate rock (PR in soils is a primary concern for P in the PR to be available for plant. The dissolution of three PR materials, China (CPR, Ciamis (IPR and Gafsa (GPR, in eight acid Indonesian soils (pH in water 4.1-5.7 was tested in a closed incubation system. Experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The dissolution was determined from the increase in either 0.5 M NaOH extractable P (∆P or 1 M BaCl2-triethanolamine (TEA-extractable Ca (∆Ca in soils amended with PR compared with control soil. Dissolution of the IPR was the highest (30-100% followed by GPR (17-69% and then by CPR (20-54%. The maximum dissolution followed the order: Bogor Ultisols > Bogor Oxisols > Subang Inceptisols > Bogor Inceptisols > Sukabumi Oxisols > Lebak Ultisols > Sukabumi Inceptisols > Lampung Ultisols. PR dissolution indicated a positive correlation with P retention capacity. The results implied that the extent of PR dissolution for the three PR sources (China, Indonesia and Tunisia increased with increasing P retention capacity of the soils. PR dissolution can be based on a calibration curve of ∆Ca meaning that if ∆P is high then the amount of PR dissolution measured by ∆Ca in PR materials is also high.

  18. Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA Composites: Effect of Coupling Agent Mediated Interface

    Directory of Open Access Journals (Sweden)

    Gavin Walker

    2012-10-01

    Full Text Available In this study three chemical agents Amino-propyl-triethoxy-silane (APS, sorbitol ended PLA oligomer (SPLA and Hexamethylene diisocyanate (HDI were identified to be used as coupling agents to react with the phosphate glass fibre (PGF reinforcement and the polylactic acid (PLA polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP control, supporting the use of these materials as coupling agent’s within medical implant devices.

  19. Coating of ß-tricalcium phosphate scaffolds-a comparison between graphene oxide and poly-lactic-co-glycolic acid.

    Science.gov (United States)

    Ardjomandi, N; Henrich, A; Huth, J; Klein, C; Schweizer, E; Scheideler, L; Rupp, F; Reinert, S; Alexander, D

    2015-08-04

    Bone regeneration in critical size defects is a major challenge in oral and maxillofacial surgery, and the gold standard for bone reconstruction still requires the use of autologous tissue. To overcome the need for a second intervention and to minimize morbidity, the development of new biomaterials with osteoinductive features is the focus of current research. As a scaffolding material, ß-tricalcium phosphate (ß-TCP) is suitable for bone regeneration purposes, although it does not carry any functional groups for the covalent immobilization of molecules. The aim of the present study was to establish effective coating variants for ß-TCP constructs to enable the biofunctionalization of anorganic blocks with different osteogenic molecules in future studies. We established working protocols for thin surface coatings consisting of polylactic-co-glycolic acid (PLGA) and graphene oxide (GO) by varying parameters. Surface properties such as the angularity and topography of the developed scaffolds were analyzed. To examine biological functionality, the adhesion and proliferation behavior of jaw periosteal cells (JPCs) were tested on the coated constructs. Our results suggest that PLGA is the superior material for surface coating of ß-TCP matrices, leading to higher JPC proliferation rates and providing a more suitable basis for further biofunctionalization in the field of bone tissue engineering.

  20. Co-extraction and co-stripping of U(VI) and Pu(IV) using tri-iso-amyl phosphate and tri-n-butyl phosphate in n-dodecane from nitric acid media under high loading conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivasulu, Balija; Suresh, Ammath; Sivaraman, Nagarajan; Rao, P.R. Vasudeva [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Chemistry Group

    2016-08-01

    The extraction of Pu(IV) using 1.1 M solution of tri-iso-amyl phosphate (TiAP)/n-dodecane (DD) from plutonium nitrate solutions in nitric acid media was examined as a function of equilibrium aqueous phase metal ion concentration and equilibrium aqueous phase acidity at 303 K. The nitric acid concentration in the organic phase was measured as a function of equilibrium organic phase plutonium concentration. The co-extraction of U(VI) and Pu(IV) was studied using 1.1 M TiAP/DD system as a function of their equilibrium aqueous phase metal ion concentration and compared with 1.1 M tri-n-butyl phosphate (TBP)/n-DD system under identical conditions. Co-extraction and co-stripping of U(VI) and Pu(IV) were studied using 1.1 M TiAP/DD and 1.1 M TBP/DD systems in cross current mode to evaluate the number of stages required for the extraction and stripping of heavy metal ions (uranium and plutonium). The extraction and stripping efficiencies were calculated for both the systems. The saturation limit of the organic phase was also established in these studies.

  1. Effect of fluoride varnish with added casein phosphopeptide-amorphous calcium phosphate on the acid resistance of the primary enamel.

    Science.gov (United States)

    Tuloglu, Nuray; Bayrak, Sule; Tunc, Emine Sen; Ozer, Fusun

    2016-09-26

    This study aimed to investigate the effects of a fluoride varnish with added Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) treatments on acid resistance of primary teeth enamel. Enamel specimens obtained from 40 primary incisors (for surface microhardness testing) and 40 primary molars (for demineralization depth measurement) were randomly divided into four groups (n = 10 incisors and 10 molars) each according to surface treatment: no treatment (control), MI varnish (1-8 % sodium fluoride and 1-5 % CPP-ACP), Clinpro White (1-5 % sodium fluoride and fluoride). Specimens were stored for 24 h in a moist environment. After varnish residues were removed, specimens were subjected to pH cycling. The effects of fluoride varnishes were evaluated according to surface microhardness, lesion depth and structural changes. Results were analyzed by ANOVA and Tukey's tests. The lowest changes in surface microhardness and lesion depth occurred in MI varnish group, followed by the Clinpro White, Duraphat and no treatment (control) group (for percentage of loss surface microhardness -20.80, -34.60, -57.80 and -73.40; for lesion depth values 23.60 μm ± 3.36, 29.85 μm ± 3.27, 40.37 μm ± 3.41 and 54.56 μm ± 4.16, respectively). Statistically significant differences in both surface microhardness and lesion depth were observed among all groups (P fluoride varnish containing CPP-ACP was more effective in increasing the acid resistance of primary enamel than other fluoride varnishes. However, further clinical research is needed to confirm these in vitro results.

  2. Influence of formic acid on electrical, linear and nonlinear optical properties of potassium dihydrogen phosphate (KDP) crystals

    Energy Technology Data Exchange (ETDEWEB)

    Anis, Mohd [Crystal Growth Laboratory, Department of Physics, Milliya Arts, Science and Management Science College, Beed 431122, Maharashtra (India); Shirsat, M.D. [Intelligent Material Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431005,Maharashtra (India); Muley, Gajanan [Department of Physics, Sant Gadge Baba Amravati University, Amravati 444602, Maharashtra (India); Hussaini, S.S., E-mail: Shuakionline@yahoo.co.in [Crystal Growth Laboratory, Department of Physics, Milliya Arts, Science and Management Science College, Beed 431122, Maharashtra (India)

    2014-09-15

    In present investigation 0.5 and 1 mol% formic acid (FA) added potassium dihydrogen phosphate (KDP) crystals have been grown by a slow evaporation technique. The cell parameters of the grown crystals were determined using single crystal X-ray diffraction analysis. The presence of different functional groups has been qualitatively analyzed by the FT-IR spectral analysis. The optical transparency and optical constants were assessed employing UV–visible studies in the range of 200–900 nm. The wide optical band gap of 1 mol% FA added KDP has been found to be 5 eV. The frequency dependent dielectric measurements were studied for pure and KDP added FA crystals. The enhanced second harmonic generation (SHG) efficiency of grown crystals was determined by a classical Kurtz–Perry powder technique. The encouraging third order nonlinear properties were examined employing a Z-scan technique using He–Ne laser, at 632.8 nm. The effective negative index of refraction and high figure of merit (FOM) essential for laser stabilization were determined for grown crystals. - Highlights: • Study on electrical and optical properties of formic acid (FA) added KDP was reported for the first time. • Optical properties were found to be enhanced with increasing concentration of FA. • The SHG efficiency of 1 mol% FA added KDP was 1.13 times that of KDP. • The high concentration of FA contributed lower dielectric properties to KDP suitable for microelectronics applications. • The improved third order nonlinear parameters were ascertained with addition of FA in KDP crystal.

  3. SINTESIS PATI SAGU IKATAN SILANG FOSFAT BERDERAJAT SUBSTITUSI FOSFAT TINGGI DALAM SUASANA ASAM [Synthesis of Cross-Linked Sago Starch Phosphate with the Highest Degree of Substitution of Phosphate Under Acidic Condition

    Directory of Open Access Journals (Sweden)

    Jorion Romengga*

    2011-12-01

    Full Text Available Cross-linked sago starch phosphate (SgP with high phosphorus contents was successfully synthesized by reacting sago with a mixture of primary and secondary sodium phosphates under acidic condition. The experimental variables investigated include pH, temperature, reaction time, and mixture rate. The physicochemical properties evaluated were moisture, swelling power, water binding capacity, transmittance (%T and percent amylose (%Am, while the pasting properties examined were pasting time, pasting temperature, viscosity at peak, final, and setback. The granule structure was observed by scanning electron microscope and X-ray diffraction. The results showed that the maximum degree of phosphate substitution was obtained at pH of 6.50, 40°C, 20 minutes of reaction time and 300 rpm of mixing rate. The physicochemical (%T and %Am and pasting (viscosity at peak, final, and setback properties of SgP were significantly different (P<0.01 from Sg. Structure of SgP was characterized by FT-IR and the results indicated a new absorption peak at 2362.87 cm-1 which was characterized as the phospho-diester (RO-PO3-R’ stretching vibration. In the fingerprint area, there were two new absorption peaks at 1242.05 and 989.79 cm-1 which were characterized as the P=O and C-O-P vibration, respectively. Sago granules were substantially altered after cross-linking.

  4. Quantification of three chlorinated dialkyl phosphates, diphenyl phosphate, 2,3,4,5-tetrabromobenzoic acid, and four other organophosphates in human urine by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jayatilaka, Nayana K; Restrepo, Paula; Williams, LaTasha; Ospina, Maria; Valentin-Blasini, Liza; Calafat, Antonia M

    2017-02-01

    Polybrominated diphenyl ethers (PBDEs), produced as flame retardants worldwide, have been phased-out in many countries, and chlorinated and non-chlorinated organophosphates and non-PBDE brominated formulations (e.g., Firemaster 550 (FM550)) have entered the consumers' market. Recent studies show that components of organophosphate esters and FM550 are frequently detected in many products common to human environments. Therefore, urinary metabolites of these compounds can be used as human exposure biomarkers. We developed a method to quantify nine compounds in 0.4 mL urine: diphenyl phosphate (DPhP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), bis-(1-chloro-2-propyl) phosphate, bis-2-chloroethyl phosphate, di-p-cresylphosphate, di-o-cresylphosphate (DoCP), di-n-butyl phosphate, dibenzyl phosphate (DBzP), and 2,3,4,5-tetrabromobenzoic acid. The method relies on an enzymatic hydrolysis of urinary conjugates of the target analytes, automated off-line solid phase extraction, reversed phase high performance liquid chromatography separation, and isotope dilution-electrospray ionization tandem mass spectrometry detection. The method is high-throughput (96 samples/day) with detection limits ranging from 0.05 to 0.16 ng mL(-1). Spiked recoveries were 90-113 %, and interday imprecision was 2-8 %. We assessed the suitability of the method by analyzing urine samples collected from a convenience sample of adults (n = 76) and from a group of firefighters (n = 146). DPhP (median, 0.89; range, 0.26-5.6 ng mL(-1)) and BDCPP (median, 0.69; range, 0.31-6.8 ng mL(-1)) were detected in all of the non-occupationally exposed adult samples and all of the firefighter samples (DPhP [median, 2.9; range, 0.24-28 ng mL(-1)], BDCPP [median, 3.4; range, 0.30-44 ng mL(-1)]); DBzP and DoCP were not detected in any samples.

  5. Diglycolic acid modified zirconium phosphate and studies on the extraction of Am(III) and Eu(III) from dilute nitric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Selvan, B. Robert; Suneesh, A.S.; Venkatesan, K.A.; Antony, M.P. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Division; Dasthaiah, K.; Gardas, R.L. [Indian Institute of Technology - Madras, Chennai (India). Dept. of Chemistry

    2017-06-01

    Diglycolic acid modified zirconium phosphate (ZrP-DGA) was prepared and studied for the extraction of Am(III) and Eu(III) from dilute nitric acid medium. The distribution coefficient (K{sub d}, mL.g{sup -1}) of Am(III) and Eu(III) was measured as a function of time, pH and concentration of Eu(III) ion etc. The K{sub d} of Am(III) and Eu(III) increased with increase of pH, reached a maximum value of distribution coefficient at pH 1.5 - 2, followed by decrease in K{sub d} values. Rapid extraction of Am(III) and Eu(III) in ZrP-DGA was observed followed by the establishment of equilibrium occurred in 100 min. Kinetics of extraction was fitted in to pseudo second order rate equation. The amount of Eu(III) loaded in ZrP-DGA increased with increase in the concentration of Eu(III) ion in aqueous phase and the isotherm was fitted in to Langmuir and Freundlich adsorption models. The extraction of Am(III) in ZrP-DGA was higher as compared to Eu(III) and the interference of Eu(III) on the extraction of Am(III) was studied. The distribution coefficient of some lanthanides in ZrP-DGA was measured and the K{sub d} of lanthanides increased across the lanthanide series. The extracted trivalent metal ions were recovered in three contacts of loaded ZrP-DGA with 0.5 M nitric acid.

  6. Evaluation of commonly used methods for the analysis of acid-soluble phosphate in internationally traded inorganic fertilizers.

    Science.gov (United States)

    Hall, William L; Siegel, Sanford

    2014-01-01

    Several methodologies are used throughout the world to determine phosphate concentration (measured as PO4 and expressed as % P2O5) in fertilizers. Concentrated phosphate materials, including diammonium phosphate (DAP) and monoammonium phosphate (MAP), are traded in large volumes (millions of metric tons) internationally. The International Fertilizer Association (IFA) identified a need to assess the methods currently being used to measure the phosphate content for suitability (scope), accuracy, and repeatability. Even small discrepancies in the expressed P2O5 content can have a major financial impact on buyers and sellers as contracts are settled and import regulations are imposed. The IFA's Technical Committee selected a working group to address issues dealing with harmonization of fertilizer sampling and analytical methodologies. The working group identified phosphate content in DAP and MAP fertilizers as a major concern for commerce. The working group initiated a method screening and comparison project to assess method performance and to determine which methods, if any, could be considered best practice methods and, therefore, be deemed acceptable for use by the industry. In order to systematically review the acceptability of methods for consideration, the task force developed an assessment protocol outlined in a white paper involving three steps: (1) compile all known relevant methods practiced in global fertilizer trade, (2) review and evaluate methods based upon specific evaluation criteria, and (3) compare the methods that most closely fit the evaluation criteria by multilaboratory analysis of unknown materials for accuracy and repeatability. Six methods were evaluated for analysis of total phosphate in concentrated phosphate products. From these methods, four were determined to be acceptable as best practice methods. The study members proposed three of the methods, while a fourth method was commonly used among the participating laboratories. This publication

  7. Identification of critical amino acid residues of Saccharomyces cerevisiae carbamoyl-phosphate synthetase: definition of the ATP site involved in carboxy-phosphate formation.

    Science.gov (United States)

    Zheng, W; Lim, A L; Powers-Lee, S G

    1997-08-15

    Carbamoyl-phosphate synthetases (CPSases) utilize two molecules of ATP at two homologous domains, B and C, with ATP(B) used to form the enzyme-bound intermediate carboxy-phosphate and ATP(C) used to phosphorylate the carbamate intermediate. To further define the role of one CPSase peptide suggested by affinity labeling studies to be near the ATP(B) site, we have carried out site-directed mutagenic analysis of peptide 234-242 of the Saccharomyces cerevisiae arginine-specific CPSase. Mutants E234A, E234D, E236A, E236D and E238A were unable to complement the CPSase-deficient yeast strain LPL26 whereas mutants Y237A, E238D, R241K, R241E and R241P supported LPL26 growth as well as wild-type CPSase. Kinetic analysis of E234A and Y237A indicated impaired utilization of ATP(B) but not of ATP(C). D242A, a temperature-sensitive mutant, retained no detectable activity when assayed in vitro. These findings, together with the affinity labeling data and primary sequence analysis, strongly suggest that the yeast CPSase peptide 234-242 is located at the ATP(B) site and that some of its residues are important for functioning of the enzyme. D242 appears to occupy a critical structural position and E234, E236 and E238 appear to be critical for function, with the spatial arrangement of the carboxyl side chain also critical for E234 and E236.

  8. 21 CFR 184.1434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

    ... solution of magnesite with phosphoric acid. (b) Magnesium phosphate, dibasic, meets the specifications of... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium phosphate. 184.1434 Section 184.1434 Food... Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes...

  9. Effect of the Acidic Dental Resin Monomer 10-methacryloyloxydecyl Dihydrogen Phosphate on Odontoblastic Differentiation of Human Dental Pulp Cells.

    Science.gov (United States)

    Kim, Eun-Cheol; Park, Haejin; Lee, Sang-Im; Kim, Sun-Young

    2015-11-01

    Although 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) is frequently used as an acidic resin monomer in dental adhesives, its effect on dental pulp cells (DPCs) has been rarely reported. The purpose of this study was to examine the effects of 10-MDP on the inflammatory response and odontoblastic differentiation of DPCs at minimally toxic concentrations. We found that 10-MDP caused the release of inflammatory cytokines including NO, PGE2, iNOS, COX-2, TNF-α, IL-1β, IL-6 and IL-8 in a concentration-dependent manner. In addition, 10-MDP reduced alkaline phosphatase activity, mineralization nodule formation and mRNA expression of odontoblastic differentiation markers such as dentin sialophosphoprotein, dentin matrix protein-1, osterix and Runx2 in a concentration-dependent manner with low toxicity. In addition, 10-MDP induced activation of nuclear factor-E2-related factor 2 (Nrf2) and its target gene, haeme oxygenase-1 (HO-1). We evaluated whether the effect of 10-MDP was related to the induction of HO-1 and found that treatment with a selective inhibitor of HO-1 reversed the production of 10-MDP-mediated pro-inflammatory cytokines and the inhibition of differentiation markers. Pre-treatment with either a GSH synthesis inhibitor or antioxidants blocked 10-MDP-induced mitogen-activated protein kinases (MAPKs), Nrf2 and NF-κB pathways. Taken together, the results of this study showed that minimally toxic concentrations of 10-MDP promoted an inflammatory response and suppressed odontoblastic differentiation of DPCs by activating Nrf2-mediated HO-1 induction through MAPK and NF-κB signalling.

  10. Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

    Science.gov (United States)

    Crea, Francesco; De Stefano, Concetta; Foti, Claudia; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2016-01-01

    Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K  Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand).

  11. Lysophosphatidic Acid and Sphingosine-1-Phosphate: A Concise Review of Biological Function and Applications for Tissue Engineering.

    Science.gov (United States)

    Binder, Bernard Y K; Williams, Priscilla A; Silva, Eduardo A; Leach, J Kent

    2015-12-01

    The presentation and controlled release of bioactive signals to direct cellular growth and differentiation represents a widely used strategy in tissue engineering. Historically, work in this field has primarily focused on the delivery of large cytokines and growth factors, which can be costly to manufacture and difficult to deliver in a sustained manner. There has been a marked increase over the past decade in the pursuit of lipid mediators due to their wide range of effects over multiple cell types, low cost, and ease of scale-up. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are two bioactive lysophospholipids (LPLs) that have gained attention for use as pharmacological agents in tissue engineering applications. While these lipids can have similar effects on cellular response, they possess distinct chemical backbones, mechanisms of synthesis and degradation, and signaling pathways using a discrete set of G-protein-coupled receptors (GPCRs). LPA and S1P predominantly act extracellularly on their GPCRs and can directly regulate cell survival, differentiation, cytokine secretion, proliferation, and migration--each of the important functions that must be considered in regenerative medicine. In addition to these potent physiological functions, these LPLs play pivotal roles in a number of pathophysiological processes. To capitalize on the promise of these molecules in tissue engineering, these lipids have been incorporated into biomaterials for in vivo delivery. Here, we survey the effects of LPA and S1P on both cellular- and tissue-level phenotypes, with an eye toward regulating stem/progenitor cell growth and differentiation. In particular, we examine work that has translational applications for cell-based tissue engineering strategies in promoting cell survival, bone and cartilage engineering, and therapeutic angiogenesis.

  12. [Preliminary application of injectable calcium phosphate cement/poly (lactic-co-glycolic acid) microspheres for extraction site preservation].

    Science.gov (United States)

    Mai, Yuying; Wu, Huihuang; Mai, Zhisong; Li, Xinghong; Huang, Linhui; Liao, Hongbing

    2014-03-01

    To investigate the feasibility of extraction site preservation using injectable calcium phosphate cement (CPC) combine with poly (lactic-co-glycolic acid) (PLGA) microspheres. Immediate extraction defects models were created in canine mandibles, and the defects were filled with CPC/PLGA (experimental group, E) , Bio-Oss (positive control, P), non-treatment (blank control, B) respectively. Dogs were sacrificed after 4, 8, 12 weeks post operation. Statistical analysis were conducted using SPSS 19. of radiological observation showed that there were not significantly different between groups in 4 and 8 week (P > 0.05). After 12 week,E (114.9 ± 8.4) were not significantly different compared with P (117.4 ± 12.1) (P > 0.05) , both were significantly higher than B (95.0 ± 12.6) (P B[(78.7 ± 2.7)%] > E[(69.2 ± 1.8)%] (P < 0.05). At 8, 12 week, results of P[(94.0 ± 2.3)% and (93.5 ± 1.9) %] and E[ (94.7 ± 1.1) % and (96.0 ± 0.9) %] were better than those of B[ (76.8 ± 3.0)% and (87.0 ± 2.4)%] (P < 0.05). The effect of CPC/PLGA repair immediate alveolar ridge defects is the same as that of Bio-Oss, and CPC/PLGA can be used as a material in extraction site preservation.

  13. Preparation of core-shell PAN nanofibers encapsulated α-tocopherol acetate and ascorbic acid 2-phosphate for photoprotection.

    Science.gov (United States)

    Wu, Xiao-Mei; Branford-White, Christopher J; Yu, Deng-Guang; Chatterton, Nicholas P; Zhu, Li-Min

    2011-01-01

    Magnesium l-ascorbic acid 2-phosphate (MAAP) and α-tocopherol acetate (α-TAc), as the stable vitamin C and vitamin E derivative, respectively, are often applied to skin care products for reducing UV damage. The encapsulation of MAAP (0.5%, g/mL) and α-TAc (5%, g/mL) together within the polyacrylonitrile (PAN) nanofibers was demonstrated using a coaxial electrospinning technique. The structure and morphology characterizations of the core-shell fibers MAAP/α-TAc-PAN were investigated by SEM, FTIR and XRD. As a negative control, the blend nanofibers MAAP/α-TAc/PAN were prepared from a normal electrospinning method. The results from SEM indicated that the morphology and diameter of the nanofibers were influenced by concentration of spinning solution, the polymer component of the shell, the carrying agent of the core and the fabricating methods, and the core-shell nanofibers obtained at the concentration of 8% had finer and uniform structure with the average diameters of 200 ± 15nm. From in vitro release studies it could be seen that both different fiber specimens showed a gradual increase in the amount of α-TAc or MAAP released from the nanofibers. Furthermore, α-TAc and MAAP released from the blend nanofibers showed the burst release at the maximum release of ∼15% and ∼40% during the first 6h, respectively, but their release amount from the core-shell nanofibers was only 10-12% during the initial part of the process. These results showed that core-shell nanofibers alleviated the initial burst release and gave better sustainability compared to that of the blend nanofibers. The present study would provide a basis for further optimization of processing conditions to obtain desired structured core-shell nanofibers and release kinetics for practical applications in dermal tissue.

  14. Sodium Phosphate

    Science.gov (United States)

    Sodium phosphate is used in adults 18 years of age or older to empty the colon (large intestine, bowel) ... view of the walls of the colon. Sodium phosphate is in a class of medications called saline ...

  15. Phosphate salts

    Science.gov (United States)

    ... levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often ... But intravenous phosphate salts should not be used. Kidney stones (nephrolithiasis). Taking potassium phosphate by mouth might help ...

  16. Research of the Acidizing of Ammonium Sulfate Decomposition of Phosphate Rock%酸化硫酸铵分解磷矿研究

    Institute of Scientific and Technical Information of China (English)

    赵新菊; 李沪萍; 罗康碧; 秦令; 苏毅

    2015-01-01

    磷石膏复分解可制备硫酸铵,硫酸铵应用于磷矿分解系统可使磷钙分离简单,从而可实现磷化工企业湿法硫循环利用的目的。本研究开展了热力学分析探讨酸化硫酸铵分解磷矿的可行性,采用正交实验考察了酸化硫酸铵的酸化剂类型、H+浓度、反应温度和时间对磷矿转化率的影响,对分解滤渣进行了表征。结果表明,酸化硫酸铵分解磷矿可行,硝酸和盐酸为酸化剂的分解效果最好,硫酸和磷酸为酸化剂的效果较差,这主要是受分解过程中硫酸钙结晶的影响。正交实验的最佳方案为:酸化剂盐酸,反应时间80 min,反应温度80℃,H+浓度5.4 mol/L,磷矿最终转化率达99.89%。%Ammonium sulfate can be prepared from the phosphogypsum by the metathetical reaction, and is used for decomposition of phosphate to make separation of calcium and phosphorus simple, which can achieve the purpose of the use of wet sulfur recycling for the phosphorus chemical enterprises. To achieve this goal, this paper investigated the feasibility of acidifying ammonium sulfate to decompose phosphate by thermodynamic analysis, using orthogonal experiment to investigate the effects of types of ammonium sulfate acidiifers, concentration of H+, reaction temperature and time on the conversion rate of phosphate, and residues were characterized. The results indicate that decomposing phosphate ore through ammonium sulfate acidiifcation is feasible, the effect of nitric acid and hydrochloric acid as decomposition acidiifers are best, and sulfuric acid and phosphoric acid appear relatively poor effect, which is mainly due to the crystallization of calcium sulfate in decomposition process. The best solution for the orthogonal experiments:hydrochloric acid as an acidifying agent, reaction time 80 min, reaction temperature 80℃, H+concentration 5.4 mol/L, phosphate ifnal conversion rate can reach 99.89%.

  17. Phosphate status and acid phosphatase activity in soil and ectomycorrhizas in two mature stands of scots pine (Pinus sylvestris L. exposed to different levels of anthropogenic pollution

    Directory of Open Access Journals (Sweden)

    Barbara Kieliszewska-Rokicka

    2014-01-01

    Full Text Available The relations between anthropogenic environmental pollution and the level of inorganic phosphorus in soil, enzyme activities of extracellular soil acid phosphatase and the surface acid phosphatase of excised ectomycorrhizas of Scots pine (Pinus sylvestris L. were studied. Soil and root samples were taken from two Scots pine stands in central Poland: a polluted site exposed to long-term pollution from a steelworks and the city of Warsaw and a reference plot (control free from direct impact of pollution. The polluted site was characterised by high concentration of trace elements (Cd, Pb, Cu, Zn, Mn, Cr and low level of inorganic phosphate in soil. This site had significantly lower enzyme activities of soil acid phosphatase (0.54 µmoles p-nitrophenol released g-1 dry weight h-1 and surface acid phosphatase of pine ectomycorrhizas (3.37 µmoles p-nitrophenol released g-1 fresh weight h-1 than the control site (1.36 µmoles p-nitrophenol released g-1 dry weight h-1 and 12.46 µmoles p-nitrophenol released g-1 fresh weight h-1, respectively. The levels of phosphate, carbon and nitrogen in pine fine roots were also analysed. Low concentrations of P04-P and high N: P ratio in pine fine roots from polluted site were found. The results suggest that soil pollutants may have a negative effect on the extracellular acid phosphatase of soil and Scots pine ectomycorrhizas and on the phosphorus status in fine roots of the plant.

  18. Formation of phosphatidylinositol 3-phosphate by isomerization from phosphatidylinositol 4-phosphate.

    OpenAIRE

    Walsh, J P; Caldwell, K K; Majerus, P W

    1991-01-01

    We have synthesized phosphatidylinositol 3-phosphate from phosphatidylinositol 4-phosphate by using diisopropylcarbodiimide to promote migration of the 4-phosphate via a cyclic phosphodiester intermediate. The product was isolated by a thin-layer chromatographic method that depends on the ability of phosphatidylinositol 4-phosphate, but not phosphatidylinositol 3-phosphate, to form complexes with boric acid. The final yield of the procedure was 8% phosphatidylinositol 3-phosphate, which was a...

  19. The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

    Science.gov (United States)

    Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

    2017-09-01

    Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

  20. Effects of Low-Molecular-Weight Organic Acids on the Dissolution of Hydroxyapatite Nanoparticles in Batch and Column Experiments: A Perspective from Phosphate Oxygen Isotope Fractionation

    Science.gov (United States)

    Wang, D.; Jaisi, D. P.; Jin, Y.

    2015-12-01

    Hydroxyapatite nanoparticles (HANPs) are increasingly being advocated as an efficient and environment-friendly "green" phosphorus nanofertilizer attributed to their nanoscale dimension, large reactive surface area, and low leaching potential. However, knowledge of how naturally occurring low-molecular-weight organic acids (LMWOAs) that are secreted by plant roots mediate the dissolution of HANPs (releasing PO43- ion for plant growth) is nonexistent. Here three most commonly encountered LMWOAs (acetic acid, oxalic acid, and citric acid) at environmentally relevant concentration (1 mM) were evaluated for their effects on HANPs' dissolution in static batch and dynamic column systems. Particularly, phosphate oxygen isotope fractionation of HANPs during dissolution was examined to disentangle mechanisms controlling the evolution of O-isotopic composition of dissolved PO43- ion. Our results reveal that in batch experiments the dissolution of HANPs was fast but the overall dissolution efficiency of HANPs was limited (≤30%). In contrast, ~100% HANPs were dissolved in columns where LMWOAs were continuously injected. The limited dissolution of HANPs in static batch systems was due primarily to pH buffer effect (pH increased sharply when LMWOA was added in HANPs suspension), whereas in dynamic column systems the HANPs were continuously dissolved by low pH LMWOAs and leached away. Regardless of LMWOA type and experimental system, the isotopically light phosphate (P16O4) was preferentially released during dissolution and the O-isotopic composition of dissolved PO43- ion increased gradually with increasing dissolution due to equilibrium isotope effect between dissolved PO43- ion and HANPs. However, the overall magnitude of O-isotopic fractionation of dissolved PO43- ion was less in batch than in column systems, due to less mass transfer between dissolved PO43- ions and HANPs in batch relative to column experiments. Our findings provide new insights into bioavailability

  1. An Oral Load of [13C3]Glycerol and Blood NMR Analysis Detect Fatty Acid Esterification, Pentose Phosphate Pathway, and Glycerol Metabolism through the Tricarboxylic Acid Cycle in Human Liver.

    Science.gov (United States)

    Jin, Eunsook S; Sherry, A Dean; Malloy, Craig R

    2016-09-01

    Drugs and other interventions for high impact hepatic diseases often target biochemical pathways such as gluconeogenesis, lipogenesis, or the metabolic response to oxidative stress. However, traditional liver function tests do not provide quantitative data about these pathways. In this study, we developed a simple method to evaluate these processes by NMR analysis of plasma metabolites. Healthy subjects ingested [U-(13)C3]glycerol, and blood was drawn at multiple times. Each subject completed three visits under differing nutritional states. High resolution (13)C NMR spectra of plasma triacylglycerols and glucose provided new insights into a number of hepatic processes including fatty acid esterification, the pentose phosphate pathway, and gluconeogenesis through the tricarboxylic acid cycle. Fasting stimulated pentose phosphate pathway activity and metabolism of [U-(13)C3]glycerol in the tricarboxylic acid cycle prior to gluconeogenesis or glyceroneogenesis. Fatty acid esterification was transient in the fasted state but continuous under fed conditions. We conclude that a simple NMR analysis of blood metabolites provides an important biomarker of pentose phosphate pathway activity, triacylglycerol synthesis, and flux through anaplerotic pathways in mitochondria of human liver.

  2. Effectiveness of trisodium phosphate, acidified sodium chlorite, citric acid, and peroxyacids against pathogenic bacteria on poultry during refrigerated storage.

    Science.gov (United States)

    del Río, Elena; Muriente, Rebeca; Prieto, Miguel; Alonso-Calleja, Carlos; Capita, Rosa

    2007-09-01

    The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 +/- 1 degrees C. All chemical solutions reduced microbial populations (P 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of storage, the pH of legs treated with TSP remained higher and that of legs treated with CA

  3. Synthesis and biological evaluation of phosphate prodrugs of 4-phospho-D-erythronohydroxamic acid, an inhibitor of 6-phosphogluconate dehydrogenase.

    Science.gov (United States)

    Ruda, Gian Filippo; Alibu, Vincent P; Mitsos, Christos; Bidet, Olivier; Kaiser, Marcel; Brun, Reto; Barrett, Michael P; Gilbert, Ian H

    2007-08-01

    We have previously reported the discovery of potent and selective inhibitors of 6-phosphogluconate dehydrogenase, the third enzyme of the phosphate pentose pathway, from Trypanosoma brucei, the causative organism of human African trypanosomiasis. These inhibitors were charged phosphate derivatives with restricted capacity to enter cells. Herein, we report the synthesis of five different classes of prodrugs: phosphoramidate; bis-S-acyl thioethyl esters (bis-SATE); bis-pivaloxymethyl (bis-POM); CycloSaligenyl; and phenyl, S-acyl thioethyl mixed phosphate esters (mix-SATE). Prodrugs were studied for stability and activity against the intact parasites. Most prodrugs caused inhibition of the growth of the parasites. The activity of the prodrugs against the parasites appeared to be related to their stability in aqueous buffer.

  4. Improved biocompatibility of poly(lactic-co-glycolic acid) orv and poly-L-lactic acid blended with nanoparticulate amorphous calcium phosphate in vascular stent applications.

    Science.gov (United States)

    Zheng, Xiaoxin; Wang, Yujue; Lan, Zhiyuan; Lyu, Yongnan; Feng, Gaoke; Zhang, Yipei; Tagusari, Shizu; Kislauskis, Edward; Robich, Michael P; McCarthy, Stephen; Sellke, Frank W; Laham, Roger; Jiang, Xuejun; Gu, Wei Wang; Wu, Tim

    2014-06-01

    Biodegradable polymers used as vascular stent coatings and stent platforms encounter a major challenge: biocompatibility in vivo, which plays an important role in in-stent restenosis (ISR). Co-formulating amorphous calcium phosphate (ACP) into poly(lactic-co-glycolic acid) (PLGA) or poly-L-lactic acid (PLLA) was investigated to address the issue. For stent coating applications, metal stents were coated with polyethylene-co-vinyl acetate/poly-n-butyl methacrylate (PEVA/PBMA), PLGA or PLGA/ACP composites, and implanted into rat aortas for one and three months. Comparing with both PEVA/PBMA and PLGA groups after one month, the results showed that stents coated with PLGA/ACP had significantly reduced restenosis (PLGA/ACP vs. PEVA/PBMA vs. PLGA: 21.24 +/- 2.59% vs. 27.54 +/- 1.19% vs. 32.12 +/- 3.93%, P < 0.05), reduced inflammation (1.25 +/- 0.35 vs. 1.77 +/- 0.38 vs. 2.30 +/- 0.21, P < 0.05) and increased speed of re-endothelialization (1.78 +/- 0.46 vs. 1.17 +/- 0.18 vs. 1.20 +/- 0.18, P < 0.05). After three months, the PLGA/ACP group still displayed lower inflammation score (1.33 +/- 0.33 vs. 2.27 +/- 0.55, P < 0.05) and higher endothelial scores (2.33 +/- 0.33 vs. 1.20 +/- 0.18, P < 0.05) as compared with the PEVA/PBMA group. Moreover, for stent platform applications, PLLA/ACP stent tube significantly reduced the inflammatory cells infiltration in the vessel walls of rabbit iliac arteries relative to their PLLA cohort (NF-kappaB-positive cells: 23.31 +/- 2.33/mm2 vs. 9.34 +/- 1.35/mm2, P < 0.05). No systemic biochemical or pathological evidence of toxicity was found in either PLGA/ACP or PLLA/ACP. The co-formulation of ACP into PLGA and PLLA resulted in improved biocompatibility without systemic toxicity.

  5. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate) as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    OpenAIRE

    2013-01-01

    Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with c...

  6. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    Science.gov (United States)

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Porous poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composite for reconstruction of bone defects.

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2006-01-01

    Calcium phosphate (Ca-P) cements are injectable, self-setting ceramic pastes generally known for their favorable bone response. Ingrowth of bone and subsequent degradation rates can be enhanced by the inclusion of macropores. Initial porosity can be induced by CO(2) foaming during setting of the

  8. Porous poly(DL-lactic-co-glycolic acid)/calcium phosphate cement composite for reconstruction of bone defects.

    NARCIS (Netherlands)

    Ruhe, P.Q.; Hedberg, E.L.; Padron, N.T.; Spauwen, P.H.M.; Jansen, J.A.; Mikos, A.G.

    2006-01-01

    Calcium phosphate (Ca-P) cements are injectable, self-setting ceramic pastes generally known for their favorable bone response. Ingrowth of bone and subsequent degradation rates can be enhanced by the inclusion of macropores. Initial porosity can be induced by CO(2) foaming during setting of the cem

  9. Preparation of Surfactant-free Core-Shell Poly(lactic acid) / Calcium Phosphate Hybrid Particles and Their Drug Release Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kuno, T; Hirao, K [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555 (Japan); Nagata, F; Ohji, T; Kato, K, E-mail: katsuya-kato@aist.go.jp [Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2266-98, Anagahora, Shimoshidami, Moriyama-ku, Nagoya, 463-8510 (Japan)

    2011-04-15

    We propose surfactant-free core-shell poly(lactic acid) (PLA) / calcium phosphate (CaP) hybrid particles as drug delivery carriers. These particles were prepared by biomineralization process using ultrasonic irradiation, and their drug release profiles were investigated. Drug release rate was earlier when particles were prepared by PLA with a low molecular weight, and/or by Ca(CH{sub 3}COO){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4}. Also, these were shown good protein adsorption. This work indicates that these particles have sustained-release ability without initial burst and can do targeting capability by biomolecule conjugation.

  10. To evaluate the levels of glycated hemoglobin, serum calcium, magnesium, phosphate, uric acid and microalbuminuria in patients with newly diagnosed type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Qazi Najeeb

    2014-08-01

    Conclusion: There is decrease in serum calcium, magnesium and phosphate levels, all these plays an important role in the regulation of glucose level in the blood. Hence oral supplementation of all these ions other than diet is recommended. Increased serum uric acid and microalbuminuria was seen with reduced glucose tolerance hence early estimation of both the parameters should be done while monitoring case of Type-2 diabetes and thus will help to decrease the incidence of renal complications. [Int J Res Med Sci 2014; 2(4.000: 1462-1465

  11. Efficacité de la roche phosphatée de Matongo au travers d'un compostage sur une culture de pomme de terre sur un sol acide de Rabiro (Burundi

    Directory of Open Access Journals (Sweden)

    Van den Berghe, C.

    1993-01-01

    Full Text Available Efficiency of phosphatic rock from Matongo applied in the composting process on potatoes on an acid soil of Rabiro. In the frame of the Cooperation between the CVHA (Cultures Vivrieres de Haute Altitute Project and the Program of Fertilisation of the Agro-systems on Altitude (FAVA of the Faculty of Agricultural Sciences in Burundi, the local phosphatic rock from Matongo has been compared to diammonium-phosphate when added in the composting process. The field trials with potatoes have shown that both phosphate sources have the same fertilizing value when the enriched compost was applied at the dose of 20 t/ha. It is very interesting from agricultural and economical viewpoint to use this phosphatic rock in combination with compost.

  12. Synthesis, screening for antiacetylcholinesterase activity and binding mode prediction of a new series of [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Zanatta, Nilo; Marchi, Tiago M.; Bonacorso, Helio G.; Martins, Marcos A.P.; Flores, Alex F.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Nucleo de Quimica de Heterociclos]. E-mail: zanatta@base.ufsm.br; Borchhardt, Deise M.; Andricopulo, Adriano D.; Salum, Livia B. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Centro de Biotecnologia Molecular Estrutural. Lab. de Quimica Medicinal e Computacional; Carpes, Adriana D.; Schetinger, Maria R.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Lab. de Enzimologia Toxicologica

    2008-07-01

    A series of nine new [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters (phosphate-carbamate compounds) was obtained through the reaction of (4,4,4-trifluoro-3-hydroxybut-1-yl)-carbamic acid ethyl esters with phosphorus oxychloride followed by the addition of alcohols. The products were characterized by {sup 1}H, {sup 13}C, {sup 31}P, and {sup 19}F NMR spectroscopy, GC-MS, and elemental analysis. All the synthesized compounds were screened for acetylcholinesterase (AChE) inhibitory activity using the Ellman method. All compounds containing phosphate and carbamate pharmacophores in their structures showed enzyme inhibition, being the compound bearing the diethoxy phosphate group (2b) the most active compound. Molecular modeling studies were performed to investigate the detailed interactions between AChE active site and small-molecule inhibitor candidates, providing valuable structural insights into AChE inhibition. (author)

  13. STUDY ON THE ULTRASONIC DECOMPOSITION OF PHOSPHATE ORE- THE ULTRASONIC EXTRACTION OF PHOSPHORIC ACID%磷矿的超声分解—磷酸的超声萃取研究

    Institute of Scientific and Technical Information of China (English)

    王中华; 陈联梅; 王升; 吴珧萍; 陈天朗; 肖慎修

    2001-01-01

    The ultrasonic extraction of phosphoric acid without the stirring of oar was studied,and the influences of reaction temperature,sulfuric acid concentration,liquid-solid proportion and reaction time on the acidolysis of phosphate ore were investigated.In addition,we also preliminarily compared the experimental results with ultrasound with that from agitation.

  14. Phosphate Mines, Jordan

    Science.gov (United States)

    2008-01-01

    Jordan's leading industry and export commodities are phosphate and potash, ranked in the top three in the world. These are used to make fertilizer. The Jordan Phosphate Mines Company is the sole producer, having started operations in 1935. In addition to mining activities, the company produces phosphoric acid (for fertilizers, detergents, pharmaceuticals), diammonium phosphate (for fertilizer), sulphuric acid (many uses), and aluminum fluoride (a catalyst to make aluminum and magnesium). The image covers an area of 27.5 x 49.4 km, was acquired on September 17, 2005, and is located near 30.8 degrees north latitude, 36.1 degrees east longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. Zoledronic acid inhibits the pentose phosphate pathway through attenuating the Ras-TAp73-G6PD axis in bladder cancer cells.

    Science.gov (United States)

    Wang, Xiaolin; Wu, Guang; Cao, Guangxin; Yang, Lei; Xu, Haifei; Huang, Jian; Hou, Jianquan

    2015-09-01

    Zoledronic acid (ZA) is the current standard of care for the therapy of patients with bone metastasis or osteoporosis. ZA inhibits the prenylation of small guanosine‑5'-triphosphate (GTP)‑binding proteins, such as Ras, and thus inhibit Ras signaling. The present study demonstrated that ZA inhibited cell proliferation and the pentose phosphate pathway (PPP) in bladder cancer cells. In addition, the expression of glucose‑6‑phosphate dehydrogenase (G6PD, the rate‑limiting enzyme of the PPP) was found to be inhibited by ZA. Furthermore, the stability of TAp73, which activates the expression G6PD was decreased in zoledronic acid treated cells. Decreased levels of Ras‑GTP and phosphorylated‑extracellular signal-regulated kinase 1/2 were also observed following treatment with ZA. This may be due to the fact that activated Ras was reported to stabilize TAp73 inducing its accumulation. The inhibition of Ras activity by PT inhibitor II also significantly reduced the levels of TAp73 and G6PD and the PPP flux. Moreover, knockdown of TAp73, attenuated the PPP flux and eliminated the affection of ZA on the PPP flux. In conclusion, it was proposed that ZA can inhibit stability of TAp73 and attenuate the PPP via blocking Ras signaling in bladder cancer cells.

  16. Synthesis, characterization and fuel cell performance tests of boric acid and boron phosphate doped, sulphonated and phosphonated poly(vinyl alcohol) based composite membranes

    Science.gov (United States)

    Şahin, Alpay; Ar, İrfan

    2015-08-01

    The aim of this study is to synthesize a composite membrane having high proton conductivity, ion exchange capacity and chemical stability. In order to achieve this aim, poly(vinyl alcohol) (PVA) based composite membranes are synthesized by using classic sol-gel method. Boric acid (H3BO3) and boron phosphate (BPO4) are added to the membrane matrix in different ratios in order to enhance the membrane properties. Characterization tests, i.e; FT-IR analysis, mechanical strength tests, water hold-up capacities, swelling properties, ion exchange capacities, proton conductivities and fuel cell performance tests of synthesized membranes are carried out. As a result of performance experiments highest performance values are obtained for the membrane containing 15% boron phosphate at 0.6 V and 750 mA/cm2. Water hold-up capacity, swelling ratio, ion exchange capacity and proton conductivity of this membrane are found as 56%, 8%, 1.36 meq/g and 0.37 S/cm, respectively. These values are close to the values obtained ones for perfluorosulphonic acid membranes. Therefore this membrane can be regarded as a promising candidate for usage in fuel cells.

  17. Improved biocompatibility of novel poly(L-lactic acid/ß-tricalcium phosphate scaffolds prepared by an organic solvent-free method

    Directory of Open Access Journals (Sweden)

    Zhao XF

    2011-07-01

    Full Text Available Xue-Feng Zhao1,2, Xiao-Dong Li3, Yun-Qing Kang4, Quan Yuan1,21State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China; 2West China School of Stomatology, Sichuan University, Chengdu, People's Republic of China; 3Affiliated Hospital of Stomatology and College of Stomatology, Chongqing Medical University, Chongqing, People's Republic of China; 4College of Materials Science and Engineering, Sichuan University, Chengdu, People's Republic of ChinaAbstract: A porous poly(L-lactic acid/ß-tricalcium phosphate (PLLA/ß-TCP composite scaffold was fabricated using a novel technique comprising powder mixing, compression molding, low-temperature treatment, and particulate leaching without any organic solvent. The effect of this scaffold on osteoblast proliferation and differentiation was evaluated in vitro. The fabricated scaffold had a homogeneously interconnected porous structure with a porosity of 70% and compressive strength of 1.35 MPa. The methylthiazol tetrazolium values and alkaline phosphatase (ALP activity of osteoblasts seeded on the solvent-free scaffold were significant higher than those of the control. Using real-time PCR, gene expressions of ALP, osteocalcin, and type 1 collagen were shown to be upregulated. As the method does not use any organic solvent, it eliminates problems associated with organic solvent residue and therefore improves the cell compatibility. It has a promising potential for the preparation of porous scaffold for bone tissue engineering.Keywords: biocompatibility, biomaterials, composites, poly(L-lactic acid, ß-tricalcium phosphate

  18. Aluminium tolerance of species grown on basic to moderately acidic, and acidic soils as a function of the form of nitrogen and supply of phosphate. Die Aluminium-Toleranz von Arten basischer bis maessig saurer und saurer Boeden in Abhaengigkeit von der Stickstoff-Form und vom Phosphat-Angebot

    Energy Technology Data Exchange (ETDEWEB)

    Rode, M.W.

    1988-01-01

    The aluminium tolerance of species growing on basic to moderately acidic soils (C. remota, B. sylvaticum, O. vulgare, G. urbanum, M. muralis) and on acidic soils (J. squarrosus, A. flexuosa, C. vulgaris, G. harcynicum, D. purpurea) was tested as a function of the form of nitrogen and supply of phosphate in nutrient solution cultures. The following questions were investigated: Are the examined species different as to nitrogen uptake and especially as to OH/sup -/ or H/sup +/ release. Are nitrogen uptake and/or the release of OH/sup -/ respectively H/sup +/ influenced by aluminium. Does increased precipitation of aluminium have an influence on its toxicity.

  19. Tuning the degradation rate of calcium phosphate cements by incorporating mixtures of polylactic-co-glycolic acid microspheres and glucono-delta-lactone microparticles.

    Science.gov (United States)

    Sariibrahimoglu, Kemal; An, Jie; van Oirschot, Bart A J A; Nijhuis, Arnold W G; Eman, Rhandy M; Alblas, Jacqueline; Wolke, Joop G C; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Jansen, John A

    2014-11-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has investigated whether degradation of apatite-forming cements can be tuned by incorporating acid-producing slow-resorbing poly(D,L-lactic-co-glycolic) acid (PLGA) porogens, fast-resorbing glucono-delta-lactone (GDL) porogens, or mixtures thereof. The physicochemical, mechanical, and degradation characteristics of these CPC formulations were systematically analyzed upon soaking in phosphate-buffered saline (PBS). In parallel, various CPC formulations were implanted intramuscularly and orthotopically on top of the transverse process of goats followed by analysis of the soft tissue response and bone ingrowth after 12 weeks. In vitro degradation of GDL was almost completed after 2 weeks, as evidenced by characterization of the release of gluconic acid, while PLGA-containing CPCs released glycolic acid throughout the entire study (12 weeks), resulting in a decrease in compression strength of CPC. Extensive in vitro degradation of the CPC matrix was observed upon simultaneous incorporation of 30% PLGA-10% GDL. Histomorphometrical evaluation of the intramuscularly implanted samples revealed that all CPCs exhibited degradation, accompanied by an increase in capsule thickness. In the in vivo goat transverse process model, incorporation of 43% PLGA, 30% PLGA-5% GDL, and 30% PLGA-10% GDL in CPC significantly increased bone formation and resulted in higher bone height compared with both 10% GDL and 20% GDL-containing CPC samples.

  20. PuPO4(cr, hyd.) Solubility Product and Pu3+ Complexes With Phosphate and Ethylenediaminetetraacetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Dhanpat; Moore, Dean A.; Felmy, Andrew R.; Rosso, Kevin M.; Bolton, Harvey

    2010-06-15

    To determine the solubility product of PuPO4(cr, hyd.) and the complexation constants of Pu(III) with phosphate and EDTA, the solubility of PuPO4(cr, hyd.) was investigated as a function of: 1) time and pH varying from 1.0 to 12.0 and at a fixed 0.00032 M phosphate concentration; 2) NaH2PO4 concentrations varying from 0.0001 M to 1.0 M and at a fixed pH value of 2.5; 3) time and pH varying from 1.3 to 13.0 at fixed concentrations of 0.00032 M phosphate and 0.0004 M or 0.002 M Na2H2EDTA; and 4) Na2H2EDTA concentrations varying from 0.00005 M to 0.0256 M at a fixed 0.00032 M phosphate concentration and at pH values of approximately 3.5, 10.6, and 12.6. A combination of solvent extraction and spectrophotometric techniques confirmed that the use of hydroquinone and Na2S2O4 helped maintain Pu as Pu(III). The solubility data were interpreted using Pitzer and SIT models, and both provided similar values for the solubility product of PuPO4(cr, hyd.) and for the formation constant of PuEDTA-. The log10 of the solubility product of PuPO4(cr, hyd.) (PuPO4(cr, hyd.) = Pu3+ + PO4 ) was determined to be –(24.42 ± 0.38). Pitzer modeling showed that phosphate interactions with Pu3+ were extremely weak and did not require any phosphate complexes (e.g., PuPO4(aq), PuH2PO42+, Pu(H2PO4)2+, Pu(H2PO4)3(aq), and Pu(H2PO4)4-), as proposed in existing literature, to explain the experimental data. SIT modeling, however, required the inclusion of PuH2PO42+ to explain the data in high NaH2PO4 concentrations; this illustrates the differences one can expect when using these two chemical models to interpret the data. As the Pu(III)-EDTA species, only PuEDTA- was needed to interpret the experimental data in a large range in pH values (1.3–12.9) and EDTA concentrations (0.00005–0.256 M). Calculations based on density functional theory support the existence of PuEDTA- (with prospective stoichiometry as Pu(OH2)3EDTA-) as the chemically and structurally stable species. The log10 of the

  1. Effect of several germination conditions on total P, phytate P, phytase, and acid phosphatase activities and inositol phosphate esters in rye and barley.

    Science.gov (United States)

    Centeno, C; Viveros, A; Brenes, A; Canales, R; Lozano, A; de la Cuadra, C

    2001-07-01

    Two assays were conducted to study the evolution of rye and barley phosphatases (phytase and acid phosphatase) and the degradation of its substrates (inositol phosphate esters) during seed germination. In this manner we could obtain a low-phytate, endogenous phosphatase rich ingredient to be used in animal nutrition. In the first assay, the seeds were soaked for 1 and 14 h and germinated for 3 and 5 days with and without the addition of gibberellic acid (GA3). In the second assay, the seeds were soaked for 1 h and germinated for 1, 3, and 5 days with GA3. Phytase (up to 5739 and 3151 U x kg(-1)) and acid phosphatase (up to 18288 and 3151 U x g(-1)) activities, and IP6 (6.09 and 6.01 mg x g(-1)), IP5 (0.48 and 0.48 mg x g(-1)), and IP4 (0.13 and 0.06 mg x g(-1)) were detected in ungerminated rye and barley, respectively. The germination process caused a significant increase of Phy and AcPh activities in rye (up to 112 and 213%) and barley (up to 212 and 634%) and a reduction in the phytate phosphorus content (up to 84 and 58%, respectively). Phytate phosphorus content was affected only by soaking time in the case of rye. Finally, during the course of germination, IP6 and IP5 were rapidly degraded in rye (88 and 79%) and barley (67 and 52%), and IP4 was only a short-living intermediate, which was increased during hydrolysis and degraded to IP3. In conclusion, a marked increase of Phy and AcPh activities in rye and barley with a concomitant decrease in phytate phosphorus content and an increase in the content of lower inositol phosphates were observed during the rye and barley germination.

  2. Preparation of porous lanthanum phosphate with templates

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Hiroaki, E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Faculty of Life and Environmental Sciences, Kyoto Prefectural University, 1-5, Shimogamo Nakaragi-cyo, Sakyo-ku, Kyoto 606-8522 (Japan); Ishima, Yuya [Department of Applied Chemistry, Faculty of Life Sciences, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Takenaka, Atsushi [Department of Materials Science, Yonago National College of Technology, 4448, Hikona-cho, Yonago, Tottori 683-8502 (Japan); Tanaka, Isao [Department of Materials Science and Engineering, Faculty of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2009-08-05

    Malonic acid, propionic acid, glycine, n-butylamine, and urea were added to the preparation of lanthanum phosphate from lanthanum nitrate and phosphoric acid solutions. All additives were taken into lanthanum phosphate particles. The additives that have a basic site were easy to contain in precipitates. The addition of templates improved the specific surface area of lanthanum phosphate. The amount of pore, with radius smaller than 4 nm, increased with the addition of templates. The remained additives had influence on the acidic properties of lanthanum phosphate.

  3. Complexes of Silver(I Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

    Directory of Open Access Journals (Sweden)

    Vojtech Adam

    2013-06-01

    Full Text Available Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other

  4. Further increased production of free fatty acids by overexpressing a predicted transketolase gene of the pentose phosphate pathway in Aspergillus oryzae faaA disruptant.

    Science.gov (United States)

    Tamano, Koichi; Miura, Ai

    2016-09-01

    Free fatty acids are useful as source materials for the production of biodiesel fuel and various chemicals such as pharmaceuticals and dietary supplements. Previously, we attained a 9.2-fold increase in free fatty acid productivity by disrupting a predicted acyl-CoA synthetase gene (faaA, AO090011000642) in Aspergillus oryzae. In this study, we achieved further increase in the productivity by overexpressing a predicted transketolase gene of the pentose phosphate pathway in the faaA disruptant. The A. oryzae genome is predicted to have three transketolase genes and overexpression of AO090023000345, one of the three genes, resulted in phenotypic change and further increase (corresponding to an increased production of 0.38 mmol/g dry cell weight) in free fatty acids at 1.4-fold compared to the faaA disruptant. Additionally, the biomass of hyphae increased at 1.2-fold by the overexpression. As a result, free fatty acid production yield per liter of liquid culture increased at 1.7-fold by the overexpression.

  5. Insights into the mechanism of extraction of uranium (VI) from nitric acid solution into an ionic liquid by using tri-n-butyl phosphate.

    Science.gov (United States)

    Gaillard, Dr Clotilde; Boltoeva, Maria; Billard, Isabelle; Georg, Sylvia; Mazan, Valérie; Ouadi, Ali; Ternova, Dariia; Hennig, Christoph

    2015-08-24

    We present new results on the liquid-liquid extraction of uranium (VI) from a nitric acid aqueous phase into a tri-n-butyl phosphate/1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (TBP/[C4 mim][Tf2 N]) phase. The individual solubilities of the ionic-liquid ions in the upper part of the biphasic system are measured over the whole acidic range and as a function of the TBP concentration. New insights into the extraction mechanism are obtained through the in situ characterization of the extracted uranyl complexes by coupling UV/Vis and extended X-ray absorption fine structure (EXAFS) spectroscopy. We propose a chemical model to explain uranium (VI) extraction that describes the data through a fit of the uranyl distribution ratio DU . In this model, at low acid concentrations uranium (VI) is extracted as the cationic complex [UO2 (TBP)2 ](2+) , by an exchange with one proton and one C4 mim(+) . At high acid concentrations, the extraction proceeds through a cationic exchange between [UO2 (NO3 )(HNO3 )(TBP)2 ](+) and one C4 mim(+) . As a consequence of this mechanism, the variation of DU as a function of TBP concentration depends on the C4 mim(+) concentration in the aqueous phase. This explains why noninteger values are often derived by analysis of DU versus [TBP] plots to determine the number of TBP molecules involved in the extraction of uranyl in an ionic-liquid phase.

  6. Apicoplast-Localized Lysophosphatidic Acid Precursor Assembly Is Required for Bulk Phospholipid Synthesis in Toxoplasma gondii and Relies on an Algal/Plant-Like Glycerol 3-Phosphate Acyltransferase.

    Directory of Open Access Journals (Sweden)

    Souad Amiar

    2016-08-01

    Full Text Available Most apicomplexan parasites possess a non-photosynthetic plastid (the apicoplast, which harbors enzymes for a number of metabolic pathways, including a prokaryotic type II fatty acid synthesis (FASII pathway. In Toxoplasma gondii, the causative agent of toxoplasmosis, the FASII pathway is essential for parasite growth and infectivity. However, little is known about the fate of fatty acids synthesized by FASII. In this study, we have investigated the function of a plant-like glycerol 3-phosphate acyltransferase (TgATS1 that localizes to the T. gondii apicoplast. Knock-down of TgATS1 resulted in significantly reduced incorporation of FASII-synthesized fatty acids into phosphatidic acid and downstream phospholipids and a severe defect in intracellular parasite replication and survival. Lipidomic analysis demonstrated that lipid precursors are made in, and exported from, the apicoplast for de novo biosynthesis of bulk phospholipids. This study reveals that the apicoplast-located FASII and ATS1, which are primarily used to generate plastid galactolipids in plants and algae, instead generate bulk phospholipids for membrane biogenesis in T. gondii.

  7. Biphasic calcium phosphate ceramic combined with fibrillar collagen with and without citric acid conditioning in the treatment of periodontal osseous defects.

    Science.gov (United States)

    Nery, E B; Eslami, A; Van Swol, R L

    1990-03-01

    The purpose of this study is to determine whether the combination of biphasic calcium phosphate ceramic (BCP) and collagen and citric acid root conditioning would promote accelerated new attachment of periodontal tissue to the root surface in dogs. Intrabony defects were surgically produced for each animal and were made chronic for 16 weeks. These defects were assigned to two study treatment and one control group: ceramic-collagen without citric acid (CO-CE); ceramic-collagen with citric acid (CO-CE-CA); and control (surgical debridement and root planing only). Results showed that all groups gained new attachment level as demonstrated both clinically and histometrically. The treatment groups showed a significant mean gain greater than the control (P less than .005), but no significant difference was found between treatment groups. Small areas of ankylosis was also found in both treatments but there was no evidence of active root resorption. It is concluded that the use of combined BCP and fibrillar collagen is beneficial in promoting new attachment of periodontal tissues to the root surface in dogs. Although citric acid root conditioning did as well or better than ceramic and collagen alone, its benefits are still speculative and need further experimentation.

  8. Bio-inspired dicalcium phosphate anhydrate/poly(lactic acid) nanocomposite fibrous scaffolds for hard tissue regeneration: in situ synthesis and electrospinning.

    Science.gov (United States)

    Chae, Taesik; Yang, Heejae; Ko, Frank; Troczynski, Tom

    2014-02-01

    The fundamental building blocks of hierarchically structured bone tissue are mineralized collagen fibrils with calcium phosphate nanocrystals that are biologically "engineered" through biomineralization. In this study, we demonstrate an original invention of dicalcium phosphate anhydrate (DCPA)/poly(lactic acid) (PLA) composite nanofibers, which mimics the mineralized collagen fibrils via biomimetic in situ synthesis and electrospinning for hard tissue regenerative medicines. The interaction of the Ca(2+) ions and the carbonyl groups in the PLA provides nucleation sites for DCPA during the in situ synthesis process. This resulted in the improved dispersion of DCPA nanocrystallites in the intrananoporous PLA nanofibers through electrospinning, compared to the severely agglomerated clusters of DCPA nanoparticles fabricated by conventional mechanical blending/electrospinning methods. The addition of poly(ethylene glycol), as a copolymer source, generated more stable and efficient electrospun jets and aided in the electrospinability of the PLA nanofibers incorporating the nanocrystallites. It is expected that the uniformly distributed DCPA nanocrystallites and its unique nanocomposite fibrous topography will enhance the biological performance and the structural stability of the scaffolds used for hard tissue reconstruction and regeneration.

  9. Sustained delivery of calcium and orthophosphate ions from amorphous calcium phosphate and poly(L-lactic acid)-based electrospinning nanofibrous scaffold

    Science.gov (United States)

    Niu, Xufeng; Liu, Zhongning; Tian, Feng; Chen, Siqian; Lei, Lei; Jiang, Ting; Feng, Qingling; Fan, Yubo

    2017-01-01

    The purpose of this study is to investigate electrospinning poly(L-lactic acid) (PLLA) nanofibrous scaffold with different contents of amorphous calcium phosphate (ACP), which is suitable for using in bone regeneration through sustained release of calcium and orthophosphate ions. Three groups of nanofibrous scaffolds, ACP-free PLLA, ACP-5 wt%/PLLA and ACP-10 wt%/PLLA, are developed and characterized by scanning electron microscopy and gel permeation chromatography. Calcium and phosphate colorimetric assay kits are used to test ions released from scaffold during hydrolytic degradation. The results show ACP-5 wt%/PLLA and ACP-10 wt%/PLLA scaffolds have relatively high degradation rates than ACP-free PLLA group. The bioactivity evaluation further reveals that ACP-5 wt%/PLLA scaffold presents more biocompatible feature with pre-osteoblast cells and significant osteogenesis ability of calvarial bone defect. Due to the facile preparation method, sustained calcium and orthophosphate release behavior, and excellent osteogenesis capacity, the presented ACP/PLLA nanofibrous scaffold has potential applications in bone tissue engineering. PMID:28361908

  10. Fabrication of Poly-l-lactic Acid/Dicalcium Phosphate Dihydrate Composite Scaffolds with High Mechanical Strength—Implications for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Nida Tanataweethum

    2015-11-01

    Full Text Available Scaffolds were fabricated from poly-l-lactic acid (PLLA/dicalcium phosphate dihydrate (DCPD composite by indirect casting. Sodium citrate and PLLA were used to improve the mechanical properties of the DCPD scaffolds. The resulting PLLA/DCPD composite scaffold had increased diametral tensile strength and fracture energy when compared to DCPD only scaffolds (1.05 vs. 2.70 MPa and 2.53 vs. 12.67 N-mm, respectively. Sodium citrate alone accelerated the degradation rate by 1.5 times independent of PLLA. Cytocompatibility of all samples were evaluated using proliferation and differentiation parameters of dog-bone marrow stromal cells (dog-BMSCs. The results showed that viable dog-BMSCs attached well on both DCPD and PLLA/DCPD composite surfaces. In both DCPD and PLLA/DCPD conditioned medium, dog-BMSCs proliferated well and expressed alkaline phosphatase (ALP activity indicating cell differentiation. These findings indicate that incorporating both sodium citrate and PLLA could effectively improve mechanical strength and biocompatibility without increasing the degradation time of calcium phosphate cement scaffolds for bone tissue engineering purposes.

  11. Fabrication of Poly-l-lactic Acid/Dicalcium Phosphate Dihydrate Composite Scaffolds with High Mechanical Strength—Implications for Bone Tissue Engineering

    Science.gov (United States)

    Tanataweethum, Nida; Liu, Wai Ching; Scott Goebel, W.; Li, Ding; Chu, Tien Min

    2015-01-01

    Scaffolds were fabricated from poly-l-lactic acid (PLLA)/dicalcium phosphate dihydrate (DCPD) composite by indirect casting. Sodium citrate and PLLA were used to improve the mechanical properties of the DCPD scaffolds. The resulting PLLA/DCPD composite scaffold had increased diametral tensile strength and fracture energy when compared to DCPD only scaffolds (1.05 vs. 2.70 MPa and 2.53 vs. 12.67 N-mm, respectively). Sodium citrate alone accelerated the degradation rate by 1.5 times independent of PLLA. Cytocompatibility of all samples were evaluated using proliferation and differentiation parameters of dog-bone marrow stromal cells (dog-BMSCs). The results showed that viable dog-BMSCs attached well on both DCPD and PLLA/DCPD composite surfaces. In both DCPD and PLLA/DCPD conditioned medium, dog-BMSCs proliferated well and expressed alkaline phosphatase (ALP) activity indicating cell differentiation. These findings indicate that incorporating both sodium citrate and PLLA could effectively improve mechanical strength and biocompatibility without increasing the degradation time of calcium phosphate cement scaffolds for bone tissue engineering purposes. PMID:26556380

  12. Permeation and metabolism of a novel ascorbic acid derivative, disodium isostearyl 2-O-L-ascorbyl phosphate, in human living skin equivalent models.

    Science.gov (United States)

    Shibayama, H; Hisama, M; Matsuda, S; Ohtsuki, M

    2008-01-01

    A novel amphiphilic vitamin C (VC) derivative, disodium isostearyl 2-O-L-ascorbyl phosphate (VCP-IS-2Na), which possesses a C(18) alkyl chain attached to a stable ascorbate derivative, sodium L-ascorbic acid 2-phosphate (VCP-Na), was evaluated as a topical prodrug of VC with transdermal activity in human living skin equivalent (LSE) models. The permeation assay used was EPI-606X in the Franz-type diffusion cell system. VCP-IS-2Na exhibited much better permeability than VC and VCP-Na. The accumulation assays applied were EPI-200X and LSE-high by the dynamic system. The increased skin accumulation of VCP-IS-2Na was superior to that of VCP-Na and VC. VCP-IS-2Na that is susceptible to enzymatic hydrolysis by esterase and/or phosphatase released VC in the skin. Measurement of the metabolites that permeated and accumulated from the skin model suggested that VCP-IS-2Na was mainly metabolized via VCP-Na to VC in EPI-606X and EPI-200X, while it was mainly metabolized directly to VC in TESTSKIN LSE-high. Thus, these characteristics indicate that the novel VC derivative, VCP-IS-2Na, may be advantageous as a readily available source of VC for skin care applications.

  13. [Bioconversion of conjugated linoleic acid by resting cells of Lactobacillus plantarum ZS2058 in potassium phosphate buffer system].

    Science.gov (United States)

    Niu, Xiao-yan; Chen, Wei; Tian, Feng-wei; Zhao, Jian-xin; Zhang, Hao

    2007-04-01

    Lactobacillus plantarum ZS2058, which was screened from the Chinese traditional fermented vegetable, has the capacity to convert the linoleic acid (LA) into conjugated linoleic acid (CLA). Some specific isomers of CLA with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from free linoleic acid by washed cells of Lactobacillus plantarum ZS2058 under aerobic conditions. The produced CLA isomers are identified as the mixture of cis-9, trans-ll-octadecadienoic acid (CLA1) trans-10, cis-12-octadecadienoic acid (CLA2), 96.4% of which is CLA1. The washed cells of Lactobacillus plantarum ZS2058 producing high levels of c9, t11-CLA were obtained by cultivated in MRS media containing 0.5 mg/mL linoleic acid, indicating that the enzyme system for CLA production is induced by linoleic acid. After a 24-hour bioconversion at 37 degrees C with shaking (120 r/min), 312.4 microg/mL c9, t11-CLA is produced. And after a 36-hour bioconversion, the content of c9, t11-CLA decreases while hydroxy-octadecaenoic acid increases. In addition, the c9, t11-CLA isomer can be transformed to hydroxy- octadecaenoic acid when the mixed CLA (c9, t11-CLA and t10, c12-CLA) were used as the substrate, which suggests that c9, t11-CLA is one of the intermediates of the bioconversion products from free LA by washed cells of Lactobacillus plantarum ZS2058.

  14. Convenient synthesis of β-allenic α-difluoromethylenephosphonic acid monoesters: Potential synthons for cyclic phosphate mimics

    Institute of Scientific and Technical Information of China (English)

    Yun Lin; Jin Tao Liu

    2007-01-01

    β-Allenic α-difluoromethylenephosphonic acid monoesters were prepared under mild conditions for the first time by hydrolyzing the corresponding diethyl phosphonates in aqueous sodium hydroxide solution.

  15. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid, sodium ascorbate, calcium ascorbate, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate as a feed additive for all animal species based on a dossier submitted by DSM Nutritional Products Ltd

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Vitamin C is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and its calcium and sodium salts, ascorbyl palmitate, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplementation of feed with vitamin C. The exposure is far below the guidance level. Any potential contribution of the use of vitamin C in feed is therefore already considered in the above data. Consequently, the use of vitamin C in animal nutrition is not of concern for consumer safety. In the absence of inhalation toxicity studies it would be prudent to assume that inhalation of dust from the additives presents a health hazard to workers. Sodium calcium ascorbyl phosphate is not an irritant to skin and eyes and is unlikely to be a skin sensitiser. This conclusion is extrapolated to sodium ascorbyl phosphate. In the absence of data, ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate should be considered as irritant to skin and eyes and as dermal sensitisers. The supplementation of feed with vitamin C does not pose a risk to the environment. Ascorbic acid, sodium calcium ascorbyl phosphate and sodium ascorbyl phosphate are regarded as effective sources of vitamin C when added to feed or water for drinking. Since ascorbic acid, sodium ascorbate, calcium ascorbate and ascorbyl palmitate are authorised for use as antioxidants in food and their function in feed is essentially the same as that in food, no further demonstration of efficacy is considered necessary.

  16. Biochemical and molecular characterization of potential phosphate-solubilizing bacteria in acid sulfate soils and their beneficial effects on rice growth.

    Science.gov (United States)

    Panhwar, Qurban Ali; Naher, Umme Aminun; Shamshuddin, Jusop; Jusop, Shamshuddin; Othman, Radziah; Latif, Md Abdul; Ismail, Mohd Razi

    2014-01-01

    A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia). The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmol(c) kg(-1), respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB) including 19 N2-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis). The isolated strains were capable of producing indoleacetic acid (IAA) and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65%) existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM) was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils.

  17. Effects of low molecular weight organic acids on the immobilization of aqueous Pb(II) using phosphate rock and different crystallized hydroxyapatite.

    Science.gov (United States)

    Wei, Wei; Cui, Jing; Wei, Zhenggui

    2014-06-01

    Understanding the effects of low molecular weight organic acids (LMWOAs) on the transformation of Pb(II) to geochemically stable pyromorphite (PY) by apatite materials (AMs), has considerable benefits for risk assessment and remediation strategies for contaminated water and soil. In this study, we systematically investigated the immobilization of Pb(II) from aqueous solution by natural phosphate rock (PR) and different crystallized hydroxyapatite (HAp) in the absence and presence of LMWOAs (oxalic, malic and citric acids). The results indicated that the effectiveness of PR and HAp in immobilizing Pb(II) followed in descending order by HAp2 (the poorly crystallized HAp), HAp1 (the well crystallized HAp) and PR, regardlessof the presence of LMWOAs. The presence of malic and citric acids significantly decreased the immobilizationefficiency of Pb(II) by HAp1 and PR, clarifying the lower adsorption affinities of Pb(II)-organic acid complexes on HAp1 and PR rather than Pb(II) ion. On thecontrary, oxalic acid could markedly enhance the removal of Pb(II) from aqueous solution by HAp1 and PR through the formation of lead oxalate, which was confirmed by FT-IR and XRDanalysis. Results also showed that LMWOAs had little promoting or inhibiting effect on the immobilization of Pb(II) by HAp2. This study suggested that the ubiquity of LMWOAs in natural environments could retard the transformation efficiency of Pb(II) to PY by AMs, especiallyin thepresenceof oxalic acid, and the poorly crystallized HAp2 had great potential to remediate Pb(II)-contaminated water and soil due to its insusceptibility to LMWOAs.

  18. Biochemical and molecular characterization of potential phosphate-solubilizing bacteria in acid sulfate soils and their beneficial effects on rice growth.

    Directory of Open Access Journals (Sweden)

    Qurban Ali Panhwar

    Full Text Available A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia. The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmol(c kg(-1, respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB including 19 N2-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis. The isolated strains were capable of producing indoleacetic acid (IAA and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65% existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils.

  19. Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Vassiliev, Anton; Jensen, Jens Oluf

    2015-01-01

    Phosphoric acid and phosphoric acid doped polymer membranes are widely used as electrolytes in hydrogen based fuel cells operating at elevated temperatures. Such electrolytes have been explored for direct oxidation of methanol to further increase the versatility of the systems, however, with demo...

  20. Crystal structure of Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase complexed with an analogue of 1,3-bisphospho-d-glyceric acid.

    Science.gov (United States)

    Ladame, Sylvain; Castilho, Marcelo S; Silva, Carlos H T P; Denier, Colette; Hannaert, Véronique; Périé, Jacques; Oliva, Glaucius; Willson, Michèle

    2003-11-01

    We report here the first crystal structure of a stable isosteric analogue of 1,3-bisphospho-d-glyceric acid (1,3-BPGA) bound to the catalytic domain of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) in which the two phosphoryl moieties interact with Arg249. This complex possibly illustrates a step of the catalytic process by which Arg249 may induce compression of the product formed, allowing its expulsion from the active site. Structural modifications were introduced into this isosteric analogue and the respective inhibitory effects of the resulting diphosphorylated compounds on T. cruzi and Trypanosoma brucei gGAPDHs were investigated by enzymatic inhibition studies, fluorescence spectroscopy, site-directed mutagenesis, and molecular modelling. Despite the high homology between the two trypanomastid gGAPDHs (> 95%), we have identified specific interactions that could be used to design selective irreversible inhibitors against T. cruzi gGAPDH.

  1. Glutamate and GABA-metabolizing enzymes in post-mortem cerebellum in Alzheimer's disease: phosphate-activated glutaminase and glutamic acid decarboxylase.

    Science.gov (United States)

    Burbaeva, G Sh; Boksha, I S; Tereshkina, E B; Savushkina, O K; Prokhorova, T A; Vorobyeva, E A

    2014-10-01

    Enzymes of glutamate and GABA metabolism in postmortem cerebellum from patients with Alzheimer's disease (AD) have not been comprehensively studied. The present work reports results of original comparative study on levels of phosphate-activated glutaminase (PAG) and glutamic acid decarboxylase isoenzymes (GAD65/67) in autopsied cerebellum samples from AD patients and matched controls (13 cases in each group) as well as summarizes published evidence for altered levels of PAG and GAD65/67 in AD brain. Altered (decreased) levels of these enzymes and changes in links between amounts of these enzymes and other glutamate-metabolizing enzymes (such as glutamate dehydrogenase and glutamine synthetase-like protein) in AD cerebella suggest significantly impaired glutamate and GABA metabolism in this brain region, which was previously regarded as not substantially involved in AD pathogenesis.

  2. [Phosphate solubilization of Aureobasidium pullulan F4 and its mechanism].

    Science.gov (United States)

    Wang, Dan; Zhan, Jing; Sun, Qing-Ye

    2014-07-01

    The Aureobasidium pullulans F4 was isolated from the rhizosphere of Hippochaete ramosissimum in Tongguanshan mine wasteland in Tongling City, Anhui Province. Liquid culture was conducted with four kinds of phosphorus sources, calcium phosphate, aluminum phosphate, ferric phosphate and rock phosphate to determine the pH, dissolved phosphorus, phosphorus in the bacteria and organic acid in the solution. The results showed that the phosphate solubilization by A. pullulans F4 varied with phosphorus sources, which decreased in order of aluminum phosphate > ferric phosphate, calcium phosphate > rock phosphate. The amounts of dissolved phosphorus in the different treatments were all higher than 200 mg x L(-1). The pH of the medium dropped immediately in 48 h, and the aluminum phosphate and ferric phosphate treatments showed a greater decrease in pH than the calcium phosphate and rock phosphate treatments. The organic acid synthesized by A. pullulans F4 included oxalic acid, citric acid and tartaric acid, and oxalic acid, among which oxalic acid was the dominated component. The phosphate dissolving capacity of A. pullulans F4 showed no significant correlation with organic acid, but significantly correlated with the pH. The available phosphorus was significantly improved with the combined application of A. pullulans F4 and glucose, suggesting A. pullulans F4 was a potent candidate for remediation of copper mine wastelands.

  3. Synthesis and inhibitor performance of phosphated sulphonate acid%膦磺酸型阻垢剂的合成及性能研究

    Institute of Scientific and Technical Information of China (English)

    武林焕; 王雪梅

    2012-01-01

    Three kinds of antisludging agent containing dimethyl fork phosphonic acid amino and organic sulfonic acid are synthesized effectively. The effects to calcium carbonate dirty, calcium phosphate dirty, steady zinc, calcium chelation value and corrosion inhibition properties are investigated, respectively. The results show that the phosphine-sulfonic acid type scale inhibitors performance is greatly superior to the common organic phosphonate scale and corrosion inhibitor ATMP and HEDP, the effect of scale inhibitor is equivalent to the most excellent PBTCA and is close to AA/AMPS. Meanwhile, it has the properties of corrosion inhibition under a certain concentration.%合成了3种二甲叉膦酸基氨基有机类磺酸型阻垢剂,考察了阻碳酸钙垢、磷酸钙垢、稳定锌、分散氧化铁、钙螯合值及缓蚀性能.结果表明,合成的膦磺酸型阻垢剂的性能优于常用的有机膦阻垢缓蚀剂ATMP、HEDP,与最优良的PBTCA相当,接近AA/AMPS,且在一定浓度下,具有一定的缓蚀作用.

  4. Competitive adsorption of phosphate and several organic acids on Al(OH)x surfaces%铝(氢)氧化物对有机酸和磷酸根的竞争吸附研究

    Institute of Scientific and Technical Information of China (English)

    胡红青; 贺纪正; 李学垣

    2001-01-01

    Competitive adsorption of phosphate and o rganic acid ligand onAl (OH)x surface was studied under various concentration ratio of phosphate to oxalate (Cp/Cox) or addition order, mixture of several organic acids, and equilibrium time. The results showed: (1) The effect of organic acid on decreasing phosphate adsorption varied with the addition order of them. When the organic acid was introduced before phosphate addition, the effect of organic acid on P adsorption was the most remarkable; but when the organic acid was added after phosphate addition, it was the least effective; and when they were added as a mixture or when phosphate was added after organic acid was sorbed, then discarded through centrifuging, the effect of organic acid was in the middle. (2) When phosphate was added as a mixture with two or three kinds of organic acids to Al (OH)x mineral, the reduction of phosphate adsorption amount by Al (OH)x was different with that in the system of single organic acid. The reduction degree was related to the kind and concentration of organic acids. Because of the competition among phosphate and different organic anions, the final effect was not equal to the sum of single organic acids. (3)The amount of phosphate adsorption in the presence of citrate or oxalate was increased with the equilibrium time prolonging from 1 to 7 days. The relative affinity played a more important role for competitive adsorption.%研究了磷/草酸浓度比(Cp/Cox)、草酸(OX)与磷(P)加入顺序、多种有机酸共存等条件下铝(氢)氧化物(Al(OH)x)对有机酸和磷的吸附量变化。结果表明:磷浓度一定时,随Cp/Cox减小,Al(OH)x吸附磷量降低,吸附OX量增高,吸附阴离子总量一般随浓度升高而增加;Cp/Cox相同时,5种加入方式吸P顺序为P/OX>P-OX>OX+P>OX-P>OX/P;Cp/Cox不同时,Al(OH)x吸附配位体的总量也相应变化;几种有机酸共存时,Al(OH)x对体系中的各种阴离子均有吸附,且

  5. Generation of stable 'low phytic acid' transgenic rice through antisense repression of the 1D-myo-inositol 3-phosphate synthase gene (RINO1) using the 18-kDa oleosin promoter.

    Science.gov (United States)

    Kuwano, Mio; Mimura, Tetsuro; Takaiwa, Fumio; Yoshida, Kaoru T

    2009-01-01

    Phytic acid acts as the major storage form of phosphorus in plant seeds and is poorly digested by monogastric animals. The degradation of phytic acid in animal diets is necessary to overcome both environmental and nutritional issues. The enzyme 1D-myo-inositol 3-phosphate [Ins(3)P(1)] synthase (EC 5.5.1.4) catalyses the first step of myo-inositol biosynthesis and directs phytic acid biosynthesis in seeds. The rice Ins(3)P(1) synthase gene (RINO1) is highly expressed in developing seed embryos and in the aleurone layer, where phytic acid is synthesized and stored. In rice seeds, 18-kDa oleosin (Ole18) is expressed in a seed-specific manner, and its transcripts are restricted to the embryo and the aleurone layer. Therefore, to effectively suppress phytic acid biosynthesis, antisense RINO1 cDNA was expressed under the control of the Ole18 promoter, directing the same spatial pattern in seeds as RINO1 in transgenic rice plants. The generated transgenic rice plants showed strong 'low phytic acid' (lpa) phenotypes, in which seed phytic acid was reduced by 68% and free available phosphate was concomitantly increased. No negative effects on seed weight, germination or plant growth were observed. The available phosphate levels of the stable transgenic plants surpassed those of currently available rice lpa mutants.

  6. Over-expression of the bacterial phytase US417 in Arabidopsis reduces the concentration of phytic acid and reveals its involvement in the regulation of sulfate and phosphate homeostasis and signaling.

    Science.gov (United States)

    Belgaroui, Nibras; Zaidi, Ikram; Farhat, Ameny; Chouayekh, Hichem; Bouain, Nadia; Chay, Sandrine; Curie, Catherine; Mari, Stéphane; Masmoudi, Khaled; Davidian, Jean-Claude; Berthomieu, Pierre; Rouached, Hatem; Hanin, Moez

    2014-11-01

    Phytic acid (PA) is the main phosphorus storage form in plant seeds. It is recognized as an anti-nutrient for humans and non-ruminant animals, as well as one of the major sources of phosphorus that contributes to eutrophication. Therefore, engineering plants with low PA content without affecting plant growth capacity has become a major focus in plant breeding. Nevertheless, lack of knowledge on the role of PA seed reserves in regulating plant growth and in maintaining ion homeostasis hinders such an agronomical application. In this context, we report here that the over-expression of the bacterial phytase PHY-US417 in Arabidopsis leads to a significant decrease in seed PA, without any effect on the seed germination potential. Interestingly, this over-expression also induced a higher remobilization of free iron during germination. Moreover, the PHY-over-expressor lines show an increase in inorganic phosphate and sulfate contents, and a higher biomass production after phosphate starvation. Finally, phosphate sensing was altered because of the changes in the expression of genes induced by phosphate starvation or involved in phosphate or sulfate transport. Together, these results show that the over-expression of PHY-US417 reduces PA concentration, and provide the first evidence for the involvement of PA in the regulation of sulfate and phosphate homeostasis and signaling.

  7. Bone Healing Improvements Using Hyaluronic Acid and Hydroxyapatite/Beta-Tricalcium Phosphate in Combination: An Animal Study

    Science.gov (United States)

    Chang, Yen-Lan; Lo, Yi-June; Huang, Yu-Chih; Tsai, Hsin-Yuan; Lin, Che-Tong; Fan, Kan-Hsin

    2016-01-01

    The purpose of this study was to investigate whether the use of HLA as an aqueous binder of hydroxyapatite/beta-tricalcium phosphate (HA-βTCP) particles can reduce the amount of bone graft needed and increase ease of handling in clinical situations. In this study, HA/βTCP was loaded in commercially available crosslinking HLA to form a novel HLA/HA-βTCP composite. Six New Zealand White rabbits (3.0–3.6 kg) were used as test subjects. Four 6 mm defects were prepared in the parietal bone. The defects were filled with the HLA/HA-βTCP composite as well as HA-βTCP particle alone. New bone formation was analyzed by micro-CT and histomorphometry. Our results indicated that even when the HA-βTCP particle numbers were reduced, the regenerative effect on bone remained when the HLA existed. The bone volume density (BV/TV ratio) of HLA/HA-βTCP samples was 1.7 times larger than that of the control sample at week 2. The new bone increasing ratio (NBIR) of HLA/HA-βTCP samples was 1.78 times higher than the control group at week 2. In conclusion, HA-βTCP powder with HLA contributed to bone healing in rabbit calvarial bone defects. The addition of HLA to bone grafts not only promoted osteoconduction but also improved handling characteristics in clinical situations. PMID:28070520

  8. Comparative evaluation of microhardness of dentin treated with 4% titanium tetrafluoride and 1.23% acidic phosphate fluoride gel before and after exposure to acidic pH: An ex vivo study

    Science.gov (United States)

    Kandanuru, Vivek; Madhusudhana, Koppolu; Ramachandruni, Vamsi Krishna; Vitta, Harish Madhav; Babu, Lenin

    2016-01-01

    Aim: The aim of this study was to comparatively evaluate the effect of 4% titanium tetrafluoride (TiF4) and 1.23% acidic phosphate fluoride (APF) gel on the microhardness of human coronal dentin. Materials and Methods: Thirty noncarious extracted premolars were collected and sectioned buccolingually with the help of diamond disk. Exposing the sectioned surface, teeth were embedded in self-cure acrylic. Exposed coronal dentin was polished with abrasive papers starting with 220–5000 grit. Microhardness was evaluated by Vickers microhardness evaluator, at four different stages as follows - stage 1: Baseline values, Stage 2: Exposure of specimens to acidic environment at a pH 1 for 5 min, Stage 3: Application of 1.23% APF gel and 4% TiF4 (after dividing the specimens into two groups, i.e., Group A and B, respectively), and Stage 4: Followed by exposure of fluoridated specimens to acidic protocol as mentioned above. Results: Paired t-test was used to compare the readings between Groups A and B. Group B has shown greater resistance to decrease in microhardness of coronal dentin (P < 0.05) on exposure to acidic protocol. Conclusion: Due to acidic pH (1.5) of 4% TiF4, amount of increase in microhardness of dentin is <1.23% APF gel. 4% TiF4 was more effective in resisting demineralization than 1.23% APF gel. PMID:27994319

  9. Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP)-mediated Calcium Signaling and Arrhythmias in the Heart Evoked by β-Adrenergic Stimulation*♦

    Science.gov (United States)

    Nebel, Merle; Schwoerer, Alexander P.; Warszta, Dominik; Siebrands, Cornelia C.; Limbrock, Ann-Christin; Swarbrick, Joanna M.; Fliegert, Ralf; Weber, Karin; Bruhn, Sören; Hohenegger, Martin; Geisler, Anne; Herich, Lena; Schlegel, Susan; Carrier, Lucie; Eschenhagen, Thomas; Potter, Barry V. L.; Ehmke, Heimo; Guse, Andreas H.

    2013-01-01

    Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca2+-releasing second messenger known to date. Here, we report a new role for NAADP in arrhythmogenic Ca2+ release in cardiac myocytes evoked by β-adrenergic stimulation. Infusion of NAADP into intact cardiac myocytes induced global Ca2+ signals sensitive to inhibitors of both acidic Ca2+ stores and ryanodine receptors and to NAADP antagonist BZ194. Furthermore, in electrically paced cardiac myocytes BZ194 blocked spontaneous diastolic Ca2+ transients caused by high concentrations of the β-adrenergic agonist isoproterenol. Ca2+ transients were recorded both as increases of the free cytosolic Ca2+ concentration and as decreases of the sarcoplasmic luminal Ca2+ concentration. Importantly, NAADP antagonist BZ194 largely ameliorated isoproterenol-induced arrhythmias in awake mice. We provide strong evidence that NAADP-mediated modulation of couplon activity plays a role for triggering spontaneous diastolic Ca2+ transients in isolated cardiac myocytes and arrhythmias in the intact animal. Thus, NAADP signaling appears an attractive novel target for antiarrhythmic therapy. PMID:23564460

  10. Ethylene signalling is involved in regulation of phosphate starvation-induced gene expression and production of acid phosphatases and anthocyanin in Arabidopsis

    KAUST Repository

    Lei, Mingguang

    2010-11-30

    With the exception of root hair development, the role of the phytohormone ethylene is not clear in other aspects of plant responses to inorganic phosphate (Pi) starvation. The induction of AtPT2 was used as a marker to find novel signalling components involved in plant responses to Pi starvation. Using genetic and chemical approaches, we examined the role of ethylene in the regulation of plant responses to Pi starvation. hps2, an Arabidopsis mutant with enhanced sensitivity to Pi starvation, was identified and found to be a new allele of CTR1 that is a key negative regulator of ethylene responses. 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, increases plant sensitivity to Pi starvation, whereas the ethylene perception inhibitor Ag+ suppresses this response. The Pi starvation-induced gene expression and acid phosphatase activity are also enhanced in the hps2 mutant, but suppressed in the ethylene-insensitive mutant ein2-5. By contrast, we found that ethylene signalling plays a negative role in Pi starvation-induced anthocyanin production. These findings extend the roles of ethylene in the regulation of plant responses to Pi starvation and will help us to gain a better understanding of the molecular mechanism underlying these responses. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

  11. Dual functions of the trans-2-enoyl-CoA reductase TER in the sphingosine 1-phosphate metabolic pathway and in fatty acid elongation.

    Science.gov (United States)

    Wakashima, Takeshi; Abe, Kensuke; Kihara, Akio

    2014-09-05

    The sphingolipid metabolite sphingosine 1-phosphate (S1P) functions as a lipid mediator and as a key intermediate of the sole sphingolipid to glycerophospholipid metabolic pathway (S1P metabolic pathway). In this pathway, S1P is converted to palmitoyl-CoA through 4 reactions, then incorporated mainly into glycerophospholipids. Although most of the genes responsible for the S1P metabolic pathway have been identified, the gene encoding the trans-2-enoyl-CoA reductase, responsible for the saturation step (conversion of trans-2-hexadecenoyl-CoA to palmitoyl-CoA) remains unidentified. In the present study, we show that TER is the missing gene in mammals using analyses involving yeast cells, deleting the TER homolog TSC13, and TER-knockdown HeLa cells. TER is known to be involved in the production of very long-chain fatty acids (VLCFAs). A significant proportion of the saturated and monounsaturated VLCFAs are used for sphingolipid synthesis. Therefore, TER is involved in both the production of VLCFAs used in the fatty acid moiety of sphingolipids as well as in the degradation of the sphingosine moiety of sphingolipids via S1P.

  12. Lactic acid and thermal treatments trigger the hydrolysis of myo-inositol hexakisphosphate and modify the abundance of lower myo-inositol phosphates in barley (Hordeum vulgare L..

    Directory of Open Access Journals (Sweden)

    Barbara U Metzler-Zebeli

    Full Text Available Barley is an important source of dietary minerals, but it also contains myo-inositol hexakisphosphate (InsP6 that lowers their absorption. This study evaluated the effects of increasing concentrations (0.5, 1, and 5%, vol/vol of lactic acid (LA, without or with an additional thermal treatment at 55°C (LA-H, on InsP6 hydrolysis, formation of lower phosphorylated myo-inositol phosphates, and changes in chemical composition of barley grain. Increasing LA concentrations and thermal treatment linearly reduced (P<0.001 InsP6-phosphate (InsP6-P by 0.5 to 1 g compared to the native barley. In particular, treating barley with 5% LA-H was the most efficient treatment to reduce the concentrations of InsP6-P, and stimulate the formation of lower phosphorylated myo-inositol phosphates such as myo-inositol tetraphosphate (InsP4 and myo-inositol pentaphosphates (InsP5. Also, LA and thermal treatment changed the abundance of InsP4 and InsP5 isomers with Ins(1,2,5,6P4 and Ins(1,2,3,4,5P5 as the dominating isomers with 5% LA, 1% LA-H and 5% LA-H treatment of barley, resembling to profiles found when microbial 6-phytase is applied. Treating barley with LA at room temperature (22°C increased the concentration of resistant starch and dietary fiber but lowered those of total starch and crude ash. Interestingly, total phosphorus (P was only reduced (P<0.05 in barley treated with LA-H but not after processing of barley with LA at room temperature. In conclusion, LA and LA-H treatment may be effective processing techniques to reduce InsP6 in cereals used in animal feeding with the highest degradation of InsP6 at 5% LA-H. Further in vivo studies are warranted to determine the actual intestinal P availability and to assess the impact of changes in nutrient composition of LA treated barley on animal performance.

  13. Electrospinning of calcium phosphate-poly(D,L-lactic acid nanofibers for sustained release of water-soluble drug and fast mineralization

    Directory of Open Access Journals (Sweden)

    Fu QW

    2016-10-01

    Full Text Available Qi-Wei Fu,1,* Yun-Peng Zi,1,* Wei Xu,1 Rong Zhou,1 Zhu-Yun Cai,1 Wei-Jie Zheng,1 Feng Chen,2 Qi-Rong Qian1 1Department of Orthopedics, Changzheng Hospital, Second Military Medical University, 2State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(D,L-lactic acid (ACP-PLA nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63 cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due

  14. 2-Aryl(pyrrolidin-4-yl)acetic acids are potent agonists of sphingosine-1-phosphate (S1P) receptors.

    Science.gov (United States)

    Yan, Lin; Budhu, Richard; Huo, Pei; Lynch, Christopher L; Hale, Jeffrey J; Mills, Sander G; Hajdu, Richard; Keohane, Carol A; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Mandala, Suzanne M

    2006-07-01

    A series of 2-aryl(pyrrolidin-4-yl)acetic acids were synthesized and their biological activities were evaluated as agonists of S1P receptors. These analogs were able to induce lowering of lymphocyte counts in the peripheral blood of mice and were found to have good overall pharmacokinetic properties in rat.

  15. Role of phosphate in the central metabolism of two lactic acid bacteria-a comparative systems biology approach

    NARCIS (Netherlands)

    Levering, J.; Musters, M.W.J.M.; Bekker, M.; Bellomo, D.; Fiedler, T.; Vos, de W.M.; Hugenholtz, F.; Kreikemeyer, B.; Kummer, U.; Teusink, B.

    2012-01-01

    Lactic acid-producing bacteria survive in distinct environments, but show common metabolic characteristics. Here we studied the dynamic interactions of the central metabolism in Lactococcus lactis, extensively used as a starter culture in the dairy industry, and Streptococcus pyogenes, a human patho

  16. EFFECT OF PHOSPHATE ON NODULE PRIMORDIA OF SOYBEAN (Glycine max Merrill IN ACID SOILS IN RHIZOTRON EXPERIMENTS

    Directory of Open Access Journals (Sweden)

    Setiyo Hadi Waluyo

    2016-10-01

    Full Text Available To clarify whether P had a direct or indirect effect on the nodulation  process of soybean grown in acid soils from Sitiung, West Sumatra, Indonesia, a series of rhizotron experiments, with special attention given to formation of nodule primordia, was conducted at Laboratory of  Microbiology, Wageningen University in 1998-2000. It was shown that Ca and P were essential nutrients for root growth, nodule formation, and growth of soybean in the acid soils (Oxisols. Ca increased root growth, number of nodule primordia, nodules, and growth of the soybean plant. This positive effect of Ca was increased considerably by the application of P. Ca and P have a synergistic effect on biological nitrogen fixation (BNF of soybean in acid soils. Ca is important for the establishment of nodules, whilst P is essential for the development and function of the formed nodules. P increased number of nodule primordia, thus it also has an important role in the initiation of nodule formation. From this study, it can be concluded that Ca and P are the most limiting nutrients for BNF of soybean in the acid soils of Sitiung, West Sumatra, Indonesia.

  17. Electrospinning of calcium phosphate-poly (d,l-lactic acid) nanofibers for sustained release of water-soluble drug and fast mineralization.

    Science.gov (United States)

    Fu, Qi-Wei; Zi, Yun-Peng; Xu, Wei; Zhou, Rong; Cai, Zhu-Yun; Zheng, Wei-Jie; Chen, Feng; Qian, Qi-Rong

    Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP) nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(d,l-lactic acid) (ACP-PLA) nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63) cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due to the high biocompatibility, sustained drug release, and fast mineralization, the as-prepared composite nanofibers may have potential applications in water-soluble drug loading and release for tissue engineering.

  18. Combinatorial and sequential delivery of gemcitabine and oseltamivir phosphate from implantable poly(D,L-lactic-co-glycolic acid cylinders disables human pancreatic cancer cell survival

    Directory of Open Access Journals (Sweden)

    Allison Logan S

    2017-07-01

    Full Text Available Stephanie Allison Logan,1 Amanda J Brissenden,1 Myron R Szewczuk,2 Ronald J Neufeld1 1Department of Chemical Engineering, 2Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada Abstract: Combination therapies against multiple targets are currently being developed to prevent resistance to a single chemotherapeutic agent and to extirpate pre-existing resistance in heterogeneous cancer cells in tumors due to selective pressure from the single agent. Gemcitabine (GEM, a chemotherapeutic agent, is the current standard of care for patients with pancreatic cancer. Patients with pancreatic cancer receiving GEM have a low progression-free survival. Given the poor response rate to GEM, cancer cells are known to develop rapid resistance to this drug. Metronomic chemotherapy using combinatorial and sequential delivery systems are novel developmental approaches to disrupt tumor neovascularization, reduce systemic drug toxicity, and increase the sensitivity of chemotherapeutics in cancer. Here, implantable double-layered poly(D,L-lactic-co-glycolic acid (PLGA cylinders were engineered to sequentially release GEM in combination with oseltamivir phosphate (OP over an extended time. Double-layered PLGA cylindrical implants loaded with these active hydrophilic drugs were fabricated with minimal loss of drugs during the formulation, enabling extensive control of drug loading and establishing uniform drug distribution throughout the polymer matrix. OP is used in the formulation because of its anticancer drug properties targeting mammalian neuraminidase 1 (Neu1 involved in multistage tumorigenesis. OP and GEM encapsulated in inner/outer GEMin/OPout or OPin/GEMout implantable PLGA double-layered cylinders displayed sustained near linear release over 30 days. OP and GEM released from the double-layered cylinders effectively reduced cell viability in pancreatic cancer cell line PANC1 and its GEM-resistant variant for up to 15

  19. Electrospinning of calcium phosphate-poly (d,l-lactic acid) nanofibers for sustained release of water-soluble drug and fast mineralization

    Science.gov (United States)

    Fu, Qi-Wei; Zi, Yun-Peng; Xu, Wei; Zhou, Rong; Cai, Zhu-Yun; Zheng, Wei-Jie; Chen, Feng; Qian, Qi-Rong

    2016-01-01

    Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP) nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(d,l-lactic acid) (ACP-PLA) nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63) cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due to the high biocompatibility, sustained drug release, and fast mineralization, the as-prepared composite nanofibers may have potential applications in water-soluble drug loading and release for tissue engineering. PMID:27785016

  20. Formulation and evaluation of hydrous and anhydrous skin whitening products containing sodium ascorbyl phosphate and kojic acid dipalmitate / Marike Ganz

    OpenAIRE

    2006-01-01

    In Asia skin lightening products have grown to be the best selling skin care products, whereas in the Western hemisphere, including Europe and North America, the main demand is for the treatment of age spots and skin even toning. For African and Asian women, skin lightening is part of their culture, as lighter skin signifies increased wealth and social status. It is believed that blending vitamin C, or its derivates, with kojic acid, or its esters, could synergistically inhibit...

  1. Mechanism of enhanced antibacterial activity of ultra-fine ZnO in phosphate buffer solution with various organic acids.

    Science.gov (United States)

    Yang, Lin; Kuang, Huijuan; Liu, Yingxia; Xu, Hengyi; Aguilar, Zoraida P; Xiong, Yonghua; Wei, Hua

    2016-11-01

    Ultra-fine-ZnO showed low toxicity in complex water matrix containing multiple components such as PBS buffer and the toxic mechanism of ultra-fine-ZnO has not been clearly elucidated. In present study, enhanced antibacterial activity of 200 nm diameter ultra-fine-ZnO in PBS buffer against Bacillus cereus and Escherichia coli were observed in the presence of several organic acids in comparison with ultra-fine-ZnO in PBS buffer alone. These findings indicated that the toxic effects of the ultra-fine-ZnO was dependent on the concentration of released Zn(2+) which was affected by organic acids. The production of reactive oxygen species (ROS) did not responsible to the toxic mechanism of ultra-fine-ZnO which was tested using the antioxidant N-Acetylcysteine (NAC). Indeed, ultra-fine-ZnO induced bacteria cell membrane leakages and cell morphology damages that eventually led to cell death, which were confirmed using propidium monoazide (PMA) in combination with PCR and scanning electron microscopy (SEM). All data gathered herein suggested that released Zn(2+) played a major role in the microbial toxicity of ultra-fine-ZnO. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Optimizing Available Phosphorus in Calcareous Soils Fertilized with Diammonium Phosphate and Phosphoric Acid Using Freundlich Adsorption Isotherm

    Directory of Open Access Journals (Sweden)

    Asif Naeem

    2013-01-01

    Full Text Available In calcareous soils, phosphorus (P retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were spiked with 0, 10, and 20 % for 15 days. Freundlich adsorption isotherms ( were constructed, and theoretical doses of PA and DAP to develop a desired soil solution P level (i.e., 0.20 mg L−1 were calculated. It was observed that P adsorption in soil increased with . Moreover, at all the levels of , P adsorption from PA was lower compared to that from DAP in both the soils. Consequently, lesser quantity of PA was required to produce desired solution P, 0.2 mg L−1, compared to DAP. However, extrapolating the developed relationship between soil contents and quantity of fertilizer to other similar textured soils needs confirmation.

  3. Optimizing available phosphorus in calcareous soils fertilized with diammonium phosphate and phosphoric acid using Freundlich adsorption isotherm.

    Science.gov (United States)

    Naeem, Asif; Akhtar, Muhammad; Ahmad, Waqar

    2013-01-01

    In calcareous soils, phosphorus (P) retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA) required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were spiked with 0, 10, and 20 % CaCO3 for 15 days. Freundlich adsorption isotherms (P = aC(b/a)) were constructed, and theoretical doses of PA and DAP to develop a desired soil solution P level (i.e., 0.20 mg L(-1)) were calculated. It was observed that P adsorption in soil increased with CaCO3. Moreover, at all the levels of CaCO3, P adsorption from PA was lower compared to that from DAP in both the soils. Consequently, lesser quantity of PA was required to produce desired solution P, 0.2 mg L(-1), compared to DAP. However, extrapolating the developed relationship between soil CaCO3 contents and quantity of fertilizer to other similar textured soils needs confirmation.

  4. Inositol phosphates compete with nucleic acids for binding to bovine leukemia virus matrix protein: implications for deltaretroviral assembly.

    Science.gov (United States)

    Qualley, Dominic F; Lackey, Crystal M; Paterson, Justin P

    2013-08-01

    The matrix (MA) domain of retroviral Gag proteins plays a crucial role in virion assembly. In human immunodeficiency virus type 1 (HIV-1), a lentivirus, the presence of phosphatidylinositol-(4,5)-bisphosphate triggers a conformational change allowing the MA domain to bind the plasma membrane (PM). In this study, the MA protein from bovine leukemia virus (BLV) was used to investigate the mechanism of viral Gag binding to the membrane during replication of a deltaretrovirus. Fluorescence spectroscopy was used to measure the binding affinity of MA for two RNA constructs derived from the BLV genome as well as for single-stranded DNA (ssDNA). The importance of electrostatic interactions and the ability of inositol hexakisphosphate (IP6) to compete with nucleic acids for binding to MA were also investigated. Our data show that IP6 effectively competes with RNA and DNA for BLV MA binding, while [NaCl] of greater than 100 mM is required to produce any observable effect on DNA-MA binding. These results suggest that BLV assembly may be highly dependent on the specific interaction of the MA domain with components of the PM, as observed previously with HIV-1. The mode of MA binding to nucleic acids and the implications for BLV assembly are discussed.

  5. Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

    LENUS (Irish Health Repository)

    Costello, Richard W

    2011-05-01

    The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

  6. Mechanism of sphingosine 1-phosphate- and lysophosphatidic Acid-induced up-regulation of adhesion molecules and eosinophil chemoattractant in nerve cells.

    LENUS (Irish Health Repository)

    Costello, Richard W

    2012-02-01

    The lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) act via G-protein coupled receptors S1P(1-5) and LPA(1-3) respectively, and are implicated in allergy. Eosinophils accumulate at innervating cholinergic nerves in asthma and adhere to nerve cells via intercellular adhesion molecule-1 (ICAM-1). IMR-32 neuroblastoma cells were used as an in vitro cholinergic nerve cell model. The G(i) coupled receptors S1P(1), S1P(3), LPA(1), LPA(2) and LPA(3) were expressed on IMR-32 cells. Both S1P and LPA induced ERK phosphorylation and ERK- and G(i)-dependent up-regulation of ICAM-1 expression, with differing time courses. LPA also induced ERK- and G(i)-dependent up-regulation of the eosinophil chemoattractant, CCL-26. The eosinophil granule protein eosinophil peroxidase (EPO) induced ERK-dependent up-regulation of transcription of S1P(1), LPA(1), LPA(2) and LPA(3), providing the situation whereby eosinophil granule proteins may enhance S1P- and\\/or LPA- induced eosinophil accumulation at nerve cells in allergic conditions.

  7. On the Use of Molecular Weight Cutoff Cassettes to Measure Dynamic Relaxivity of Novel Gadolinium Contrast Agents: Example Using Hyaluronic Acid Polymer Complexes in Phosphate-Buffered Saline

    Directory of Open Access Journals (Sweden)

    Nima Kasraie

    2011-01-01

    Full Text Available The aims of this study were to determine whether standard extracellular contrast agents of Gd(III ions in combination with a polymeric entity susceptible to hydrolytic degradation over a finite period of time, such as Hyaluronic Acid (HA, have sufficient vascular residence time to obtain comparable vascular imaging to current conventional compounds and to obtain sufficient data to show proof of concept that HA with Gd-DTPA ligands could be useful as vascular imaging agents. We assessed the dynamic relaxivity of the HA bound DTPA compounds using a custom-made phantom, as well as relaxation rates at 10.72 MHz with concentrations ranging between 0.09 and 7.96 mM in phosphate-buffered saline. Linear dependences of static longitudinal relaxation rate (R1 on concentration were found for most measured samples, and the HA samples continued to produce high signal strength after 24 hours after injection into a dialysis cassette at 3T, showing superior dynamic relaxivity values compared to conventional contrast media such as Gd-DTPA-BMA.

  8. Taurine chloramine is more selective than hypochlorous acid at targeting critical cysteines and inactivating creatine kinase and glyceraldehyde-3-phosphate dehydrogenase.

    Science.gov (United States)

    Peskin, Alexander V; Winterbourn, Christine C

    2006-01-01

    Hypochlorous acid (HOCl) and chloramines are produced by the neutrophil enzyme, myeloperoxidase. Both react readily with thiols, although chloramines differ from HOCl in discriminating between low molecular weight thiols on the basis of their pKa. Here, we have compared the reactivity of HOCl and taurine chloramine with thiol proteins by examining inactivation of creatine kinase (CK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). With both enzymes, loss of activity paralleled thiol loss. For CK both were complete at a 1:1 taurine chloramine:thiol mole ratio. For GAPDH each chloramine oxidized two thiols. Three times more HOCl than taurine chloramine was required for inactivation, indicating that HOCl is less thiol specific. Competition studies showed that thiols of CK were 4 times more reactive with taurine chloramine than thiols of GAPDH (rate constants of 1200 and 300 M-1s-1 respectively). These compare with 205 M-1s-1 for cysteine and are consistent with their lower pKa's. Both enzymes were equally susceptible to HOCl. GSH competed directly with the enzyme thiols for taurine chloramine and protected against oxidative inactivation. At lower GSH concentrations, mixed disulfides were formed. We propose that chloramines should preferentially attack proteins with low pKa thiols and this could be important in regulatory processes.

  9. The Effects of Acid Passivation, Tricresyl Phosphate Presoak, and UV/Ozone Treatment on the Tribology of Perfluoropolyether-Lubricated 440C Stainless Steel Couples

    Science.gov (United States)

    Shogrin, Bradley A.; Jones, William R., Jr.; Herrera-Fierro, Pilar; Jansen, Mark J.

    2001-01-01

    The boundary-lubrication performance of two perfluoropolyether (PFPE) thin films in the presence of passivated 440C stainless steel is presented. The study used a standard ball on disk (BoD) tribometer in dry nitrogen and a vacuum spiral orbit tribometer (SOT). Stainless steel surfaces were passivated with one of four techniques: high and low temperature chromic acid bath, a tricresyl phosphate (TCP) soak, or UV/Ozone treated for 15 min. After passivation, each BoD disk had a 400A film of Krytox 16256 (PFPE) applied to it. The lifetimes of these films were quantified by measuring the number of sliding cycles before an increase in friction occurred. The lubricated lifetime of the 440C couple was not altered as a result of the various passivation techniques. The resulting surface chemistry of each passivation technique was examined using X-ray photoelectron spectroscopy (XPS). The SOT was used to examine the effects of the TCP treatment on the lubricated lifetime of another PFPE, Brayco 815Z, under rolling conditions. None of the passivation techniques were found to dramatically increase the oxide film thickness or lubricated lifetimes.

  10. Fabrication of Blended Polycaprolactone/Poly (Lactic-Co-Glycolic Acid)/β-Tricalcium Phosphate Thin Membrane Using Solid Freeform Fabrication Technology for Guided Bone Regeneration

    Science.gov (United States)

    Shim, Jin-Hyung; Huh, Jung-Bo; Park, Ju Young; Jeon, Young-Chan; Kang, Seong Soo; Kim, Jong Young; Rhie, Jong-Won

    2013-01-01

    This study developed a bioabsorbable-guided bone regeneration membrane made of blended polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and beta-tricalcium phosphate (β-TCP) using solid freeform fabrication (SFF) technology. The chemical and physical properties of the membrane were evaluated using field emission scanning electron microscopy, energy dispersive spectroscopy, and a tensile test. In vitro cell activity assays revealed that the adhesion, proliferation, and osteogenic differentiation of seeded adipose-derived stem cells (ADSCs) were significantly promoted by the PCL/PLGA/β-TCP membranes compared with PCL/PLGA membranes. When the PCL/PLGA and PCL/PLGA/β-TCP membranes were implanted on rabbit calvaria bone defects without ADSCs, microcomputed tomography and histological analyses confirmed that the SFF-based PCL/PLGA/β-TCP membranes greatly increased bone formation without the need for bone substitute materials. Moreover, tight integration, which helps to prevent exposure of the membrane, between both membranes and the soft tissues was clearly observed histologically. The SFF-based PCL/PLGA and PCL/PLGA/β-TCP membranes retained their mechanical stability for up to 8 weeks without significant collapse. Furthermore, PCL/PLGA/β-TCP underwent adequate degradation without a significant immune response at 8 weeks. PMID:22934667

  11. Therapeutic designed poly (lactic-co-glycolic acid) cylindrical oseltamivir phosphate-loaded implants impede tumor neovascularization, growth and metastasis in mouse model of human pancreatic carcinoma

    Science.gov (United States)

    Hrynyk, Michael; Ellis, Jordon P; Haxho, Fiona; Allison, Stephanie; Steele, Joseph AM; Abdulkhalek, Samar; Neufeld, Ronald J; Szewczuk, Myron R

    2015-01-01

    Poly (lactic-co-glycolic acid) (PLGA) copolymers have been extensively used in cancer research. PLGA can be chemically engineered for conjugation or encapsulation of drugs in a particle formulation. We reported that oseltamivir phosphate (OP) treatment of human pancreatic tumor-bearing mice disrupted the tumor vasculature with daily injections. Here, the controlled release of OP from a biodegradable PLGA cylinder (PLGA-OP) implanted at tumor site was investigated for its role in limiting tumor neovascularization, growth, and metastasis. PLGA-OP cylinders over 30 days in vitro indicated 20%–25% release profiles within 48 hours followed by a continuous metronomic low dose release of 30%–50% OP for an additional 16 days. All OP was released by day 30. Surgically implanted PLGA-OP containing 20 mg OP and blank PLGA cylinders at the tumor site of heterotopic xenografts of human pancreatic PANC1 tumors in RAGxCγ double mutant mice impeded tumor neovascularization, growth rate, and spread to the liver and lungs compared with the untreated cohort. Xenograft tumors from PLGA and PLGA-OP-treated cohorts expressed significant higher levels of human E-cadherin with concomitant reduced N-cadherin and host CD31+ endothelial cells compared with the untreated cohort. These results clearly indicate that OP delivered from PLGA cylinders surgically implanted at the site of the solid tumor show promise as an effective treatment therapy for cancer. PMID:26309402

  12. Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo.

    Science.gov (United States)

    Wang, Peng; Liu, Pengzheng; Peng, Haitao; Luo, Xiaoman; Yuan, Huipin; Zhang, Juncai; Yan, Yonggang

    2016-08-01

    In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 fibroblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting.

  13. A controlled release of antibiotics from calcium phosphate-coated poly(lactic-co-glycolic acid) particles and their in vitro efficacy against Staphylococcus aureus biofilm.

    Science.gov (United States)

    Bastari, Kelsen; Arshath, Mohamed; Ng, Zhi Hui Melissa; Chia, Jia Hua; Yow, Zhi Xian Daniel; Sana, Barindra; Tan, Meng Fong Cherine; Lim, Sierin; Loo, Say Chye Joachim

    2014-03-01

    Ceramic-polymer hybrid particles, intended for osteomyelitis treatment, were fabricated by preparing poly(lactic-co-glycolic acid) particles through an emulsion solvent evaporation technique, followed by calcium phosphate (CaP) coating via a surface adsorption-nucleation method. The presence of CaP coating on the surface of the particles was confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Subsequently, two antibiotics for treating bone infection, nafcillin (hydrophilic) and levofloxacin (amphiphilic), were loaded into these hybrid particles and their in vitro drug release studies were investigated. The CaP coating was shown to reduce burst release, while providing sustained release of the antibiotics for up to 4 weeks. In vitro bacterial study against Staphylococcus aureus demonstrated the capability of these antibiotic-loaded hybrid particles to inhibit biofilm formation as well as deteriorate established biofilm, making this hybrid system a potential candidate for further investigation for osteomyelitis treatment.

  14. 硝酸浸取磷矿制轻质碳酸钙工艺研究%Preparation of light calcium carbonate by nitric acid leaching phosphate ore

    Institute of Scientific and Technical Information of China (English)

    胡兆平; 贾洪秀; 庞世花; 刘阳; 贾亮

    2013-01-01

    Calcium nitrate crystal can be obtained by freezing crystallization method from acid solution acquired from nitric acid extracting phosphate rock.After that,light calcium carbonate was prepared by carbonization reaction between ammonium hydrogen carbonate and calcium nitrate crystal.Results show that,the initial carbonization reaction temperature was the normal temperature,mass fraction of calcium nitrate solution was about 23%,ammonium hydrogen carbonate and ammonia dosages were both 110% of theoretical addition amounts,and products were washed by four times of product weight washing water.All quality indexes of the product can meet the standard of Industrial Precipitated Calcium Carbonate,HG/T 2226-2000.%硝酸萃取磷矿后的酸解液,通过冷冻结晶法得到硝酸钙晶体,然后以硝酸钙为原料,通过加入碳酸氢铵进行碳化制取轻质碳酸钙.结果表明,碳化反应的初始反应温度为常温,硝酸钙溶液的质量分数为23%左右,碳酸氢铵和氨水按理论加入量的110%进行反应,用产品质量的4倍洗水量洗涤产品,制备的轻质碳酸钙产品各项指标均达到HG/T 2226-2000《工业沉淀碳酸钙》标准的要求.

  15. Reaction of pyridoxal phosphate with amino acids Electrochemical study of the Schiff bases from pyridoxal phosphates with L-leucine. Reaccion de piridoxal fosfate con aminoacido. Estudio electroquimico de las bases de Schiff de piridoxal y piridoxal fosfato con L- lencina

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, T.; Blazquez, M.; Dominguez, M.; Garcia-Blanco, F. (Departamento de Quimica Fisica y Termodinamica Aplicada. Facultad de Ciencias. Cordoba (Spain))

    1994-01-01

    The formation of the Schiff bases derived from pyridoxal (PL) and pyridoxal phosphate (PLP) with l-leucine is followed by UV-visible absorption spectroscopy. On the basis of electrochemical study of the reaction mixtures the apparent formation constant of the un protonated and mono protonated species of the Schiff base is estimated. The stability increases from Ala to Leu amino acid residues and comparatively, the Schiff base derived from PLP and hexilamine is more stable than with amino acid. The Schiff base derived from PL show the same sequence although the stability of the un protonated species shows a higher relative stability. (Author) 10 refs.

  16. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid and sodium calcium ascorbyl phosphate) as a feed additive for all animal species based on a dossier submitted by VITAC EEIG

    OpenAIRE

    2013-01-01

    Vitamin C (formerly known as antiscorbutic vitamin) is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and sodium calcium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplemen...

  17. Dolomite phosphate rock (DPR) application in acidic sandy soil in reducing leaching of phosphorus and heavy metals-a column leaching study.

    Science.gov (United States)

    Yang, Yuangen; He, Zhenli; Yang, Xiaoe; Stoffella, Peter J

    2013-06-01

    A column leaching study was designed to investigate the leaching potential of phosphorus (P) and heavy metals from acidic sandy soils applied with dolomite phosphate rock (DPR) fertilizers containing varying amounts of DPR material and N-Viro soils. DPR fertilizers were made from DPR materials mixing with N-Viro soils at the ratios of 30, 40, 50, 60, and 70 %, and applied in acidic sandy soils at the level of 100 mg available P per kilogram soil. A control and a soluble P chemical fertilizer were also included. The amended soils were incubated at room temperature with 70 % field water holding capacity for 21 days before packed into a soil column and subjected to leaching. Seven leaching events were conducted at days 1, 3, 7, 14, 28, 56, and 70, respectively, and 258.9 mL of deionized water was applied at each leaching events. The leachate was collected for the analyses of pH, electrical conductivity (EC), dissolved organic carbon (DOC), major elements, and heavy metals. DPR fertilizer application resulted in elevations up to 1 unit in pH, 7-10 times in EC, and 20-40 times in K and Ca concentrations, but 3-10 times reduction in P concentration in the leachate as compared with the chemical fertilizer or the control. After seven leaching events, DPR fertilizers with adequate DPR materials significantly reduced cumulative leaching losses of Fe, P, Mn, Cu, and Zn by 20, 55, 3.7, 2.7, and 2.5 times than chemical fertilizer or control. Even though higher cumulative losses of Pb, Co, and Ni were observed after DPR fertilizer application, the loss of Pb, Co, and Ni in leachate was <0.10 mg (in total 1,812 mL leachate). Significant correlations of pH (negative) and DOC (positive) with Cu, Pb, and Zn (P<0.01) in leachate were observed. The results indicated that DPR fertilizers had a great advantage over the soluble chemical fertilizer in reducing P loss from the acidic sandy soil with minimal likelihood of heavy metal risk to the water environment. pH elevation and high

  18. Scientific Opinion on the safety and efficacy of vitamin C (ascorbic acid and sodium calcium ascorbyl phosphate as a feed additive for all animal species based on a dossier submitted by VITAC EEIG

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-02-01

    Full Text Available Vitamin C (formerly known as antiscorbutic vitamin is essential for primates, guinea pigs and fish. Vitamin C, in the form of ascorbic acid and sodium calcium ascorbyl phosphate, is safe for all animal species. Setting a maximum content in feed and water for drinking is not considered necessary. Data on the vitamin C consumption of consumers are based on the levels of vitamin C in foodstuffs, including food of animal origin, produced in accordance with current EU legislation on the supplementation of feed with vitamin C. The exposure is far below the guidance level. Any potential contribution of the use of vitamin C in feed is therefore already considered in the above data. Consequently, the use of vitamin C in animal nutrition is not of concern for consumer safety. In the absence of inhalation toxicity studies it would be prudent to assume that inhalation of dust from the additives presents a health hazard to workers and measures should be taken to minimise inhalation exposure. In the absence of data, ascorbic acid and sodium calcium ascorbyl phosphate should be considered as irritant to skin and eyes and as dermal sensitisers. The supplementation of feed with vitamin C does not pose a risk to the environment. Ascorbic acid and sodium calcium ascorbyl phosphate are regarded as effective sources of vitamin C when added to feed or water for drinking.

  19. Co-extraction of lactic acid by tri-n-octylamine and tri-n-butyl phosphate; Tori-n-okuchiruamin to tori-n-rinsanbuchiru niyoru nyusan no kyodochushutsu

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Michiaki; Yuba, Seiji; Kondo, Kazui

    1999-01-05

    Co-extraction of lactic acid was examined as a fundamental research for establishing in situ extraction fermentation process of lactic acid (HA). Addition of tri-n-butyl phosphate (TBP) into an extraction system of lactic acid by tri-n-octylamine (TOA) using hexane as the dilutor brought about a great cooperative effect. The extracting reaction in this system is analyzed by taking into consideration the formation of HA-TOA-2TBP. Further, when a TBP and TOA-containing hexane solution was added into a culture system of a lactic acid bacteria Lactobacillus rhamnosus, latic acid of 65% in a system without addition of an organic solvent was produced. (translated by NEDO)

  20. Membrane lipid composition and stress/virulence related gene expression of Salmonella Enteritidis cells adapted to lactic acid and trisodium phosphate and their resistance to lethal heat and acid stress.

    Science.gov (United States)

    Yang, Yishan; Kadim, Mellissa Irlianti; Khoo, Wei Jie; Zheng, Qianwang; Setyawati, Magdiel Inggrid; Shin, Yu-Jin; Lee, Seung-Cheol; Yuk, Hyun-Gyun

    2014-11-17

    This study evaluated the acid and heat resistance of Salmonella Enteritidis in simulated gastric fluid (pH 2.0) and during thermal treatment (54-60 °C), respectively, after adaptation to lactic acid (LA) or trisodium phosphate (TSP) at various pHs (pH 5.3-9.0). The changes in membrane lipid composition and expression levels of RpoS and RpoH were examined to elucidate their roles in bacterial stress resistance. Transcriptional profile of several virulence-related genes was also analyzed. Results showed that LA-adapted cells at pH 5.3 and 6.3 had higher acid and heat resistance than control cells and cells adapted to TSP at pH 8.3 and 9.0. LA-adapted cells had the lowest ratio of unsaturated to saturated fatty acids, indicating that they might possess a less fluid membrane. It was observed that the expression levels of RpoH and RpoS were upregulated in TSP-adapted cells but not in LA-adapted cells. Thus, these results indicate that the increased acid and heat resistance of LA-adapted S. Enteritidis was possibly due to the decreased membrane fluidity instead of the upregulation of RpoS and RpoH. About 6.0, 2.1, and 2.46-fold upregulation of spvR, avrA, and hilA were observed in cells adapted to TSP at pH 9.0, except sefA that had its highest expression level in the control cells, indicating that the expression of these virulence genes highly depends on environmental conditions. This is the first study to show that the alteration in the cytoplasmic membrane rather than RpoS and RpoH plays a more crucial role in conferring greater acid and heat resistance on LA-adapted S. Enteritidis, thus providing a better understanding on the bacterial stress response to acidic conditions.

  1. 磷酸铁锂电池与铅酸蓄电池混合系统研究%Studies of Hybrid Energy System of Lithium Iron Phosphate Battery and Lead-acid Battery

    Institute of Scientific and Technical Information of China (English)

    袁好; 衣守忠; 王先友

    2016-01-01

    By utilizing the differences of the charging and discharging characteristics between lithium iron phosphate batteries and lead-acid batteries,a new parallel hybrid power battery system with lithium iron phosphate batteries and lead-acid batteries and new charge/discharge system are developed.When charging, the lead-acid batteries attain the priority,so that lead-acid batteries can avoid to be charged less.When dis-charging,lithium iron phosphate batteries discharge with priority,while the lead-acid batteries are on the contrary,so lead-acid batteries can work in a state of shallow cycle,which can prolong the service life of the lead-acid batteries in the hybrid system.The hybrid battery system can effectively combine the advantages of both lithium iron phosphate batteries and lead-acid batteries,such as excellent discharge rate perform-ance,long cycle life and low cost et al,which make the system suitable for the application in the field of power batteries.%利用磷酸铁锂电池与铅酸蓄电池不同的充放电特点,开发了基于磷酸铁锂电池与铅酸蓄电池并联的混合动力电源系统,并设计了新型充放电制度。充电时铅酸蓄电池优先充电,使其免于欠充电;放电时磷酸铁锂电池电优先放电,铅酸蓄电池后放电,使铅酸蓄电池处于浅循环。这种充放电制度可以明显延长混合系统中铅酸蓄电池使用寿命,并且混合动力电源系统同时具有磷酸铁锂电池倍率性能优、循环寿命长及铅酸蓄电池价格低廉等特点,在动力电池领域有巨大的应用前景。

  2. Comparative study of poly (lactic-co-glycolic acid/tricalcium phosphate scaffolds incorporated or coated with osteogenic growth factors for enhancement of bone regeneration

    Directory of Open Access Journals (Sweden)

    Shi-hui Chen

    2014-04-01

    Full Text Available Bone graft substitutes are commonly used to treat large bone defects, particularly if they can additionally act as a local delivery system for therapeutic agents capable of enhancing bone regeneration. In this study, composite scaffolds made of poly (lactic-co-glycolic acid (PLGA and tricalcium phosphate (TCP called P/T were fabricated by a low-temperature rapid prototyping technique. In order to optimise the delivery system, two different approaches for loading either the phytomolecule icaritin (ICT or bone morphogenetic protein-2 (BMP-2 were developed for an in vivo efficacy study. One was an “incorporating approach” in which the growth factor was incorporated into the scaffold during fabrication, whereas the other was a “coating approach” in which the fabricated scaffold was immersed into a preparative solution containing the growth factor. Scaffolds incorporating these growth factors were termed P/T/ICT and P/T/BMP-2, while scaffolds that had these growth factors coated on to them were named, respectively, P/T + ICT and P/T + BMP-2. A P/T scaffold without any loading was used as the control. The bone regeneration effect of these scaffolds was compared in an ulnar bone defect model in rabbits. Bone regeneration and angiogenesis was evaluated by high-resolution peripheral quantitative computed tomography and magnetic resonance imaging postimplantation. Bone regeneration was better with the P/T/ICT scaffolds with an 83.8% improvement compared with the control, and a 72.0% improvement compared with the P/T/BMP-2 treatment. Although the P/T + BMP-2 scaffold demonstrated, as expected, the best overall bone regeneration, the P/T scaffold with incorporated ICT was shown to be an innovative and cost-effective bioactive scaffold which also significantly enhanced bone regeneration with the potential to be validated for orthopaedic applications.

  3. Evolution of a Double Amino Acid Substitution in the 5-Enolpyruvylshikimate-3-Phosphate Synthase in Eleusine indica Conferring High-Level Glyphosate Resistance1

    Science.gov (United States)

    Yu, Qin; Jalaludin, Adam; Han, Heping; Chen, Ming; Sammons, R. Douglas; Powles, Stephen B.

    2015-01-01

    Glyphosate is the most important and widely used herbicide in world agriculture. Intensive glyphosate selection has resulted in the widespread evolution of glyphosate-resistant weed populations, threatening the sustainability of this valuable once-in-a-century agrochemical. Field-evolved glyphosate resistance due to known resistance mechanisms is generally low to modest. Here, working with a highly glyphosate-resistant Eleusine indica population, we identified a double amino acid substitution (T102I + P106S [TIPS]) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant individuals. This TIPS mutation recreates the biotechnology-engineered commercial first generation glyphosate-tolerant EPSPS in corn (Zea mays) and now in other crops. In E. indica, the naturally evolved TIPS mutants are highly (more than 180-fold) resistant to glyphosate compared with the wild type and more resistant (more than 32-fold) than the previously known P106S mutants. The E. indica TIPS EPSPS showed very high-level (2,647-fold) in vitro resistance to glyphosate relative to the wild type and is more resistant (600-fold) than the P106S variant. The evolution of the TIPS mutation in crop fields under glyphosate selection is likely a sequential event, with the P106S mutation being selected first and fixed, followed by the T102I mutation to create the highly resistant TIPS EPSPS. The sequential evolution of the TIPS mutation endowing high-level glyphosate resistance is an important mechanism by which plants adapt to intense herbicide selection and a dramatic example of evolution in action. PMID:25717039

  4. Evolution of a double amino acid substitution in the 5-enolpyruvylshikimate-3-phosphate synthase in Eleusine indica conferring high-level glyphosate resistance.

    Science.gov (United States)

    Yu, Qin; Jalaludin, Adam; Han, Heping; Chen, Ming; Sammons, R Douglas; Powles, Stephen B

    2015-04-01

    Glyphosate is the most important and widely used herbicide in world agriculture. Intensive glyphosate selection has resulted in the widespread evolution of glyphosate-resistant weed populations, threatening the sustainability of this valuable once-in-a-century agrochemical. Field-evolved glyphosate resistance due to known resistance mechanisms is generally low to modest. Here, working with a highly glyphosate-resistant Eleusine indica population, we identified a double amino acid substitution (T102I+P106S [TIPS]) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant individuals. This TIPS mutation recreates the biotechnology-engineered commercial first generation glyphosate-tolerant EPSPS in corn (Zea mays) and now in other crops. In E. indica, the naturally evolved TIPS mutants are highly (more than 180-fold) resistant to glyphosate compared with the wild type and more resistant (more than 32-fold) than the previously known P106S mutants. The E. indica TIPS EPSPS showed very high-level (2,647-fold) in vitro resistance to glyphosate relative to the wild type and is more resistant (600-fold) than the P106S variant. The evolution of the TIPS mutation in crop fields under glyphosate selection is likely a sequential event, with the P106S mutation being selected first and fixed, followed by the T102I mutation to create the highly resistant TIPS EPSPS. The sequential evolution of the TIPS mutation endowing high-level glyphosate resistance is an important mechanism by which plants adapt to intense herbicide selection and a dramatic example of evolution in action.

  5. Purification and Structural and Kinetic Characterization of the Pyrophosphate:Fructose-6-Phosphate 1-Phosphotransferase from the Crassulacean Acid Metabolism Plant, Pineapple.

    Science.gov (United States)

    Tripodi, KEJ.; Podesta, F. E.

    1997-03-01

    Pyrphosphate-dependent phosphofructokinase (PFP) was purified to electrophoretic homogeneity from illuminated pineapple (Ananas comosus) leaves. The purified enzyme consists of a single subunit of 61.5 kD that is immunologically related to the potato tuber PFP [beta] subunit. The native form of PFP likely consists of a homodimer of 97.2 kD, as determined by gel filtration. PFP's glycolytic activity was strongly dependent on pH, displaying a maximum at pH 7.7 to 7.9. Gluconeogenic activity was relatively constant between pH 6.7 and 8.7. Activation by Fru-2,6-bisphosphate (Fru-2,6-P2) was dependent on assay pH. In the glycolytic direction, it activated about 10-fold at pH 6.7, but only 2-fold at pH 7.7. The gluconeogenic reaction was only weakly affected by Fru-2,6-P2. The true substrates for the PFP forward and reverse reactions were Fru-6-phosphate and Mg-pyrophosphate, and Fru-1,6-P2, orthophosphate, and Mg2+, respectively. The results suggest that pineapple PFP displays regulatory properties consistent with a pH-based regulation of its glycolytic activity, in which a decrease in cytosolic pH caused by nocturnal acidification during Crassulacean acid metabolism, which could curtail its activity, is compensated by a parallel increase in its sensitivity to Fru-2,6-P2. It is also evident that the [beta] subunit alone is sufficient to confer PFP with a high catalytic rate and the regulatory properties associated with activation by Fru-2,6-P2.

  6. Ryanodine receptor type I and nicotinic acid adenine dinucleotide phosphate receptors mediate Ca2+ release from insulin-containing vesicles in living pancreatic beta-cells (MIN6).

    Science.gov (United States)

    Mitchell, Kathryn J; Lai, F Anthony; Rutter, Guy A

    2003-03-28

    We have demonstrated recently (Mitchell, K. J., Pinton, P., Varadi, A., Tacchetti, C., Ainscow, E. K., Pozzan, T., Rizzuto, R., and Rutter, G. A. (2001) J. Cell Biol. 155, 41-51) that ryanodine receptors (RyR) are present on insulin-containing secretory vesicles. Here we show that pancreatic islets and derived beta-cell lines express type I and II, but not type III, RyRs. Purified by subcellular fractionation and membrane immuno-isolation, dense core secretory vesicles were found to possess a similar level of type I RyR immunoreactivity as Golgi/endoplasmic reticulum (ER) membranes but substantially less RyR II than the latter. Monitored in cells expressing appropriately targeted aequorins, dantrolene, an inhibitor of RyR I channels, elevated free Ca(2+) concentrations in the secretory vesicle compartment from 40.1 +/- 6.7 to 90.4 +/- 14.8 microm (n = 4, p < 0.01), while having no effect on ER Ca(2+) concentrations. Furthermore, nicotinic acid adenine dinucleotide phosphate (NAADP), a novel Ca(2+)-mobilizing agent, decreased dense core secretory vesicle but not ER free Ca(2+) concentrations in permeabilized MIN6 beta-cells, and flash photolysis of caged NAADP released Ca(2+) from a thapsigargin-insensitive Ca(2+) store in single MIN6 cells. Because dantrolene strongly inhibited glucose-stimulated insulin secretion (from 3.07 +/- 0.51-fold stimulation to no significant glucose effect; n = 3, p < 0.01), we conclude that RyR I-mediated Ca(2+)-induced Ca(2+) release from secretory vesicles, possibly potentiated by NAADP, is essential for the activation of insulin secretion.

  7. Post-mortem changes in the concentration of lactic acid, phosphates and pH in the muscles of wild rabbits (Oryctolagus cuniculus) according to the perimortal situation.

    Science.gov (United States)

    Mačanga, Ján; Koréneková, Beáta; Nagy, Jozef; Marcinčák, Slavomir; Popelka, Peter; Kožárová, Ivona; Korének, Marián

    2011-08-01

    In this study changes in the concentrations of lactate, phosphates, and pH values of water extracts of muscles of transported and hunted rabbits during ripening were determined. Concentrations of lactate were higher in the muscles of hunted rabbits. The highest differences were obtained 24h after kill/hunt. Concentrations of lactate in the muscles of hunted rabbits were decreasing, while in the muscles of transported rabbits we observed it to increase in the 7th day and then decrease in the 14th day. Higher concentrations of phosphates were found in the muscles of transported wild rabbits. During the ripening process concentrations of phosphates were decreasing in muscles of both groups. Muscles of hunted rabbits had lower pH values during the whole ripening process. Our research showed that concentrations of lactate, phosphates and pH value post-mortem depended on the perimortal situations.

  8. 废硫酸调整磷酸二铵产品总养分的技改措施%Technological Transformation Measures to Adjust Diammonium Phosphate Product Total Nutrient with Waste Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    段付岗

    2011-01-01

    The reason for using waste sulfuric acid to adjust diammonium phosphate ( DAP) product total nutrient and the measures of technological transformation are presented. After the renovation, the quality of DAP product is stable, the fluctuation of mass fraction of total nutrient is only ±0.3% , attaining the aim of same effect of using raw sulfuric acid to adjust product quality, saving raw sulfuric acid 1 700 t (pure acid) annually.%介绍了利用废硫酸调整磷酸二铵(DAP)产品总养分的原因及其技改措施.改造后,DAP产品质量稳定,总养分质量分数波动仅±0.3%,达到了用原料硫酸调整产品质量的同等效果,年节约原料硫酸1 700 t(折纯).

  9. Tetracalcium phosphate: Synthesis, properties and biomedical applications.

    Science.gov (United States)

    Moseke, C; Gbureck, U

    2010-10-01

    Monoclinic tetracalcium phosphate (TTCP, Ca(4)(PO(4))(2)O), also known by the mineral name hilgenstockite, is formed in the (CaO-P(2)O(5)) system at temperatures>1300 degrees C. TTCP is the only calcium phosphate with a Ca/P ratio greater than hydroxyapatite (HA). It appears as a by-product in plasma-sprayed HA coatings and shows moderate reactivity and concurrent solubility when combined with acidic calcium phosphates such as dicalcium phosphate anhydrous (DCPA, monetite) or dicalcium phosphate dihydrate (DCPD, brushite). Therefore it is widely used in self-setting calcium phosphate bone cements, which form HA under physiological conditions. This paper aims to review the synthesis and properties of TTCP in biomaterials applications such as cements, sintered ceramics and coatings on implant metals.

  10. 磷酸装置提高萃取槽磷矿转化率的研究与应用%Study and application of increasing phosphate rock conversion rate in extraction tank of phosphoric acid plant

    Institute of Scientific and Technical Information of China (English)

    索保军

    2012-01-01

    三环分公司P2O5 80kt/a磷酸装置,磷矿转化率仅96.01%。为提高转化率,降低生产成本,在分析硫酸分解磷矿的理论和装置生产现状的基础上,从萃取工艺、设备、操作、生产管理等方面,采取了一系列技改措施,使磷矿转化率提高到97.18%,磷收率提高,经济效益显著。%The conversion rate of phosphate rock of P205 80 kt/a phosphoric acid plant in Three Cycles Branch Company is only 96.01%. For improving the conversion rate and reducing production cost, with the analysis on the decomposition theory of phosphate rock by sulfuric acid and production status, some measures are taken from extraction process, equipment, operation and production management etc. After modification, the conversion rate of phosphate rock is 97.18%, the phosphorus recovery rate in extraction tank is increased, the economic benefit is remarkable.

  11. REMOVAL OF LEAD(II) FROM SEAWATER WITH TIN(IV) ACID PHOSPHATE%磷酸锡晶体去除海水中Pb(II)研究

    Institute of Scientific and Technical Information of China (English)

    祝春水; 王丽萍; 柏静; 徐少强; 吴雪娇

    2011-01-01

    Tin(Ⅳ) acid phosphate (SnP) was used as adsorbent for the removal of Pb(II) from aqueous solutions. The extent of adsorption was investigated as a function of pH, contact time, adsorbate concentration and reaction temperature. The adsorption property of SnP in simulated seawater was also researched. Experimental results showed that the amount of adsorbed lead ions increased with the increase of solution pH in the examined range (3~6) and reaction time. The sorption process followed pseudo-second-order kinetics very well, and the rate constant k2 increased with the increasing temperatures. The equilibrium data followed Langmuir isotherm model well. The maximum sorption capacity amounted to 110.50mg/g at 20℃. The free energy Es (J/mol) got from the D-R isotherm indicated the sorption process was a chemical ion-exchange mechanism. The ion-exchange reaction was taken place between Pb2+ and H*. The negative △G0 values and the positive △H0, △S0 at various temperatures confirmed the adsorption processes were spontaneous and endothermic. Adsorption experiments conducted in stimulated seawater showed it was feasible for tin(Ⅳ) phosphate in removing Pb2+ from hyper-saline media, such as marine culture wastewater. Desorption experiment in the media of HC1 solution indicated that the adsorbent can be reclaimed and reused, which enhanced its value in practical application.%利用合成的磷酸锡晶体作为吸附剂,考察了pH值、吸附时间、初始浓度、温度等因素对吸附水溶液中pb2+的影响,同时考察了在模拟海水中的吸附效果.结果表明,磷酸锡对pb2+的吸附量随着pH(3~6)以及吸附时间的增大而增加.吸附动力学过程符合准二级动力学模型.等温吸附数据用Langmuir方程拟合效果最好,20℃时饱和吸附量达到110.50mg/g.Dubinin-Radushkevich(D-R)模型研究表明吸附机理属于化学离子交换.反应机理为磷酸锡中的H+与溶液中的pb2+发生了离子交换反应.热力

  12. Light weight phosphate cements

    Science.gov (United States)

    Wagh, Arun S.; Natarajan, Ramkumar,; Kahn, David

    2010-03-09

    A sealant having a specific gravity in the range of from about 0.7 to about 1.6 for heavy oil and/or coal bed methane fields is disclosed. The sealant has a binder including an oxide or hydroxide of Al or of Fe and a phosphoric acid solution. The binder may have MgO or an oxide of Fe and/or an acid phosphate. The binder is present from about 20 to about 50% by weight of the sealant with a lightweight additive present in the range of from about 1 to about 10% by weight of said sealant, a filler, and water sufficient to provide chemically bound water present in the range of from about 9 to about 36% by weight of the sealant when set. A porous ceramic is also disclosed.

  13. Determination of Phosphates by the Gravimetric Quimociac Technique

    Science.gov (United States)

    Shaver, Lee Alan

    2008-01-01

    The determination of phosphates by the classic quimociac gravimetric technique was used successfully as a laboratory experiment in our undergraduate analytical chemistry course. Phosphate-containing compounds are dissolved in acid and converted to soluble orthophosphate ion (PO[subscript 4][superscript 3-]). The soluble phosphate is easily…

  14. Performance of pineapple slips inoculated with diazotrophic phosphate-solubilizing bacteria and rock phosphate

    OpenAIRE

    Lílian Estrela Borges Baldotto; Marihus Altoé Baldotto; Fábio Lopes Olivares; Adriane Nunes de Souza

    2014-01-01

    Besides fixing N2, some diazotrophic bacteria or diazotrophs, also synthesize organic acids and are able to solubilize rock phosphates, increasing the availability of P for plants. The application of these bacteria to pineapple leaf axils in combination with rock phosphate could increase N and P availability for the crop, due to the bacterial activity of biological nitrogen fixation and phosphate solubilization. The objectives of this study were: (i) to select and characterize diazotrophs abl...

  15. 人工骨材料磷酸钙及硫酸钙在腱-骨愈合中的作用%Effect of calcium acid phosphate and calcium sulfate on tendon-bone healing

    Institute of Scientific and Technical Information of China (English)

    倪锋; 皇甫小桥; 赵金忠; 沙霖; 谢国明

    2011-01-01

    背景:有关促进腱-骨愈合的方法文献报道很多,主要方法就是给腱-骨间隙添加一些刺激物质,以此促进腱骨的愈合.磷酸钙盐作为生物活性材料具有骨传导性,已广泛应用于临床骨缺损的替代和填充.而硫酸钙作为人工材料,具有潜在的骨诱导活性.目的:在自体腘绳肌肌腱移植重建膝关节前交叉韧带过程中,观察人工骨材料磷酸钙及硫酸钙促进腱-骨愈合的效应.方法:选用36条雄性成熟比格犬,先行切断双侧膝关节前交叉韧带,取同侧后肢趾长屈肌腱作为移植物,采用悬吊式固定重建前交叉韧带.按随机数字表法分为3组,磷酸钙组于股骨腱骨隧道中注入磷酸钙,硫酸钙组注入硫酸钙,空白组韧带重建结束后不添加任何填充物.分别于重建后1,2,3,4,6个月取材行大体观察、组织学和生物力学观测.结果与结论:前交叉韧带重建后1,2,3,4个月时,磷酸钙组及硫酸钙组腱骨界面纤维连接明显强于空白组,而磷酸钙组、硫酸钙组差异无显著性意义.6个月时,各组愈合程度相似.生物力学方面,重建后1个月时,磷酸钙组及硫酸钙组腱骨界面的抗拉脱强度均高于空白组(P 0.05).提示磷酸钙及硫酸钙均能促进腱-骨愈合,两者之间无明显差异.%BACKGROUND: The reports are related to the promotion of tendon-bone healing are many, the main method is to give tendon-bone gap some excitor substance, so as to promote tendon-bone healing. Calcium acid phosphate as bioactive material has bone conductibility, and has been commonly used in substitution and padding of clinical bone defect. However, calcium sulfate as artificial material has potential osteoinductivity.OBJECTIVE: To observe the effect of calcium acid phosphate and calcium sulfate on tendon-bone healing during the process of anterior cruciate ligament of knee joint constructed with autologous hamstring tendon transplantation.METHODS: A total of 36 male Beagle

  16. Safety test of a supplement, 5-aminolevulinic acid phosphate with sodium ferrous citrate, in diabetic patients treated with oral hypoglycemic agents

    Directory of Open Access Journals (Sweden)

    Naohide Yamashita

    2014-09-01

    Full Text Available Objective: This study aimed to examine the safety of 5-aminolevulinic acid phosphate (5-ALA with sodium ferrous citrate (SFC in diabetic patients treated with one or more oral hypoglycemic agents (OHAs. Background: Recent intervention studies performed in the USA and Japan have shown that a nutritional supplement of 5-ALA with SFC efficiently reduced blood glucose levels in pre-diabetic population without any adverse events. Thus, it was anticipated that 5-ALA with SFC may potentially be taken as a beneficial supplement by diabetic patients who were being treated with OHA therapy. Nevertheless, it is important to examine its safety and efficacy in diabetic population. Methods: This study was a prospective single-blinded, randomized, placebo-controlled and parallel-group comparison study. Medically treated diabetic patients between the ages of 30 and 75 were recruited from the Tokyo metropolitan area of Japan and 45 subjects were selected after screening. These subjects were randomly assigned to three groups: daily intake of 15mg 5-ALA, 50mg 5-ALA, and a placebo (n=15, respectively. The supplement or placebo was administered for 12 weeks followed by a four week washout period. The primary endpoint was safety and occurrence of hypoglycemic attack, while the secondary endpoint was changes of fasting blood glucose (FBG and hemoglobin A1c (HbA1c. Results: Adverse events related to 5-ALA with SFC were not observed in all the groups. Abnormalities in blood and urine tests were not observed either. Significant decrease in FBG was not detected in all the groups. However, there was a small but significant decrease in HbA1c at 4 and 8 week in the 15 mg 5-ALA group. Significant decrease in HbA1c was not observed in the 50 mg 5-ALA group, although a tendency to decrease after 4 weeks was apparent. Conclusion: 5-ALA with SFC is a safe and potentially beneficial supplement if taken by diabetic patients treated with OHAs.

  17. Phosphate based oil well cements

    Science.gov (United States)

    Natarajan, Ramkumar

    The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement that is being used presently has several shortcomings for borehole sealant. The setting of the Portland cement in permafrost regions is poor because the water in it will freeze even before the cement sets and because of high porosity and calcium oxide, a major ingredient it gets easily affected by the down hole gases such as carbon dioxide. The concept of phosphate bonded cements was born out of considerable work at Argonne National Laboratory (ANL) on their use in stabilization of radioactive and hazardous wastes. Novel cements were synthesized by an acid base reaction between a metal oxide and acid phosphate solution. The major objective of this research is to develop phosphate based oil well cements. We have used thermodynamics along with solution chemistry principles to select calcined magnesium oxide as candidate metal oxide for temperatures up to 200°F (93.3°C) and alumina for temperatures greater than 200°F (93.3°C). Solution chemistry helped us in selecting mono potassium phosphate as the acid component for temperatures less than 200°F (93.3°C) and phosphoric acid solution greater than 200°F (93.3°C). These phosphate cements have performance superior to common Portland well cements in providing suitable thickening time, better mechanical and physical properties.

  18. Encapsulation in alginate enhanced the plant growth promoting activities of two phosphate solubilizing bacteria isolated from the phosphate mine of Gafsa

    OpenAIRE

    Mounira Ben Farhat; Salma Taktek; Hichem Chouayekh

    2014-01-01

    To develop a maize inoculant allowing the use of sparingly soluble inorganic phosphates, the potential of two phosphate solubilizing bacteria isolated from the Gafsa rock phosphate mine, namely Serratia marcescens CTM 50650 and Enterobacter sp. US468 was assessed. At first, these phosphate solubilizing bacteria were analyzed for plant growth promoting activities like acid and alkaline phosphatase, and indole acetic acid production. Both isolates produced alkaline and acid phosphatase at 35.73...

  19. Progress of Inosine Mono-phosphate(IMP) and Guanosine Mono-phosphate(GMP) Acid Production by Microbial Technology%利用微生物技术生产肌苷酸和鸟苷酸的进展

    Institute of Scientific and Technical Information of China (English)

    王美玲

    2014-01-01

    肌苷酸( IMP)和鸟苷酸( GMP)是非常有效的风味增强剂。它们和谷氨酸钠(味精)一起被广泛用作食品添加剂,共同发挥增强食物鲜味的作用。近年来,由于具有抗氧化性、神经保护作用、强心剂作用和免疫调节等有利作用,嘌呤类核苷酸都展现出了重要性。本综述回顾了利用微生物技术生产IMP和GMP的进展,包括其合成的代谢途径和调控网络,以及为获得这些嘌呤化合物所采用的生物技术流程和所用微生物菌种。%Inosine mono -phosphate ( IMP ) and guanosine mono -phosphate ( GMP ) are very effective flavor enhancers.They and mono-sodium glutamate (MSG) are widely used as food additives, working together to enhance the role of food flavors .In recent years ,with antioxidant activity ,neuro protective car-diac function and other favorable immunomodulatory effects of purine nucleotides ,they are showing further importance .The progress of microbial technology used to produce IMP and GMP are reviewed in this pa-per,including the synthesis of metabolic pathways and regulatory networks , as well as the biotechnology processes used to accept these purine compounds and microbial strains used .

  20. Mannose-6-phosphate/insulin-like growth Factor-II receptors may represent a target for the selective delivery of mycophenolic acid to fibrogenic cells

    NARCIS (Netherlands)

    Greupink, Albert; Bakker, Hester; van Goor, H.; de Borst, M.H.; Beljaars, L.; Poelstra, Klaas

    2006-01-01

    Purpose. The insulin-like growth factor axis plays an important role in fibrogenesis. However, little is known about mannose-6-phosphate/Insulin-like growth factor-II receptor (M6P/IGF-IIR) expression during fibrosis. When expressed preferentially on fibrogenic cells, this receptor may be used to se

  1. Tuning the Degradation Rate of Calcium Phosphate Cements by Incorporating Mixtures of Polylactic-co-Glycolic Acid Microspheres and Glucono-Delta-Lactone Microparticles

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; An, J.; Oirschot, B.A.J.A. van; Nijhuis, A.W.G.; Eman, R.M.; Alblas, J.; Wolke, J.G.C.; Beucken, J.J.J.P van den; Leeuwenburgh, S.C.G.; Jansen, J.A.

    2014-01-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has

  2. Tuning the Degradation Rate of Calcium Phosphate Cements by Incorporating Mixtures of Polylactic-co-Glycolic Acid Microspheres and Glucono-Delta-Lactone Microparticles

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; An, J.; Oirschot, B.A.J.A. van; Nijhuis, A.W.G.; Eman, R.M.; Alblas, J.; Wolke, J.G.C.; Beucken, J.J.J.P van den; Leeuwenburgh, S.C.G.; Jansen, J.A.

    2014-01-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has inv

  3. Preparation and Properties of Polylactic Acid/Nano Silver Loaded Zirconium Phosphate Melt-Spun Fibers%聚乳酸/纳米载银磷酸锆熔纺纤维制备及性能

    Institute of Scientific and Technical Information of China (English)

    傅超; 高明亮; 韩阜益; 李仲; 甘学辉

    2016-01-01

    利用双螺杆挤出机将聚乳酸(PLA)切片和纳米载银磷酸锆颗粒共混制备纳米载银磷酸锆质量分数为20%的PLA母粒。将母粒和纯PLA切片按照不同比例共混熔纺制备PLA/纳米载银磷酸锆共混纤维。研究了共混纤维的制备方法,运用扫描电子显微镜观察了纤维束外部形貌,测试了纤维的力学及抗菌性能。结果表明,纳米载银磷酸锆在纤维中有少量凝聚,总体分散均匀;随着纳米载银磷酸含量提升,纤维断裂强度先增大后降低,同时纤维的抗菌性不断增加。当载银磷酸锆含量达到1.5%时,纤维的断裂强度最大为0.85 cN/dtex,对大肠杆菌和金黄色葡萄球菌抑菌率达99.9%。%The polylactic acid (PLA) slice and nano silver loaded zirconium phosphate particles were mixed to prepare PLA masterbatch containing 20% mass fraction nano silver loaded zirconium phosphate by twin screw extruder. The masterbatch and pure PLA slice mixed at a different proportion were blended and melt spun to obtain different PLA/nano loaded silver zirconium phosphate blend fibers. The preparation of these blend fibers were discussed. The external morphology of the fiber bundles was observed by scanning electron microscope. The mechanical and antibacterial properties of thesefibers were tested. The results indicate that nano silver loaded zirconium phosphate particles are dispersed evenly in the blend PLA,though few particles aggregation appears. With the increase of the content of nano silver loaded zirconium phosphate,the fracture strength of thefiber increasesfirst and then decreases. When the content of silver zirconium phosphate is 1.5% by mass fraction,the maximum breaking strength of thefiber is 0.85 cN/dtex,and the antibacterial rate of the Escherichia coli and Staphylococcus aureus reaches 99.9%.

  4. Effects of Soluble Phosphate on Phosphate-Solubilizing Characteristics and Expression of gcd Gene in Pseudomonas frederiksbergensis JW-SD2.

    Science.gov (United States)

    Zeng, Qingwei; Wu, Xiaoqin; Wen, Xinyi

    2016-02-01

    Phosphate-solubilizing bacteria have the ability of solubilizing mineral phosphate in soil and promoting growth of plants, but the activity of phosphate solubilization is influenced by exogenous soluble phosphate. In the present study, the effects of soluble phosphate on the activity of phosphate solubilization, acidification of media, growth, and organic acid secretion of phosphate-solubilizing bacterium Pseudomonas frederiksbergensis JW-SD2 were investigated under six levels of soluble phosphate conditions. The activity of phosphate solubilization decreased with the increase of soluble phosphate concentration, accompanying with the increase of media pH. However, the growth was promoted by adding soluble phosphate. Production of gluconic, tartaric, and oxalic acids by the strain was reduced with the increase of concentration of soluble phosphate, while acetic and pyruvic acids showed a remarkable increase. Gluconic acid predominantly produced by the strain at low levels of soluble phosphate showed that this acid was the most efficient organic acid in phosphate solubilization. Pyrroloquinoline quinone-glucose dehydrogenase gene gcd (pg5SD2) was cloned from the strain, and the expressions of pg5SD2 gene were repressed gradually with the increase of concentration of soluble phosphate. The soluble phosphate regulating the transcription of the gcd gene is speculated to underlie the regulation of the secretion of gluconic acid and subsequently the regulation of the activity of phosphate solubilization. Future research needs to consider a molecular engineering strategy to reduce the sensitivity of PSB strain to soluble phosphate via modification of the regulatory mechanism of gcd gene, which could improve the scope of PSB strains' application.

  5. Phosphate homeostasis and disorders.

    Science.gov (United States)

    Manghat, P; Sodi, R; Swaminathan, R

    2014-11-01

    Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

  6. 13C based proteinogenic amino acid (PAA and metabolic flux ratio analysis of Lactococcus lactis reveals changes in pentose phosphate (PP pathway in response to agitation and temperature related stresses

    Directory of Open Access Journals (Sweden)

    Kamalrul Azlan Azizan

    2017-07-01

    Full Text Available Lactococcus lactis subsp. cremoris MG1363 is an important starter culture for dairy fermentation. During industrial fermentations, L. lactis is constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response of L. lactis to several stresses has been described, the adaptation mechanisms at the level of in vivo fluxes have seldom been described. To gain insights into cellular metabolism, 13C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS were used to measure the flux ratios of active pathways in the central metabolism of L. lactis when subjected to three conditions varying in temperature (30°C, 37°C and agitation (with and without agitation at 150 rpm. Collectively, the concentrations of proteinogenic amino acids (PAAs and free fatty acids (FAAs were compared, and Pearson correlation analysis (r was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA. Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability of L. lactis’ central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA from pyruvate (PYR reaction in all conditions suggested the activation of pyruvate carboxylate (pycA in L. lactis, in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering in L. lactis. Overall

  7. SAR studies of 3-arylpropionic acids as potent and selective agonists of sphingosine-1-phosphate receptor-1 (S1P1) with enhanced pharmacokinetic properties.

    Science.gov (United States)

    Yan, Lin; Huo, Pei; Hale, Jeffrey J; Mills, Sander G; Hajdu, Richard; Keohane, Carol A; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Mandala, Suzanne M

    2007-02-01

    Structure-activity relationship (SAR) studies of 3-arylpropionic acids-a class of novel S1P(1) selective agonists-by introducing substitution to the propionic acid chain and replacing the adjacent phenyl ring with pyridine led to a series of modified 3-arylpropionic acids with enhanced half-life in rat. These analogs (e.g., cyclopropanecarboxylic acids) exhibited longer half-life in rat than did unmodified 3-arylpropionic acids. This result suggests that metabolic oxidation at the propionic acid chain, particularly at the C3 benzylic position of 3-arylpropionic acids, is probably responsible for their short half-life in rodent.

  8. Comparison of greenhouse and {sup 32}P isotopic laboratory methods for evaluating the agronomic effectiveness of natural and modified rock phosphates in some acid soils of Ghana

    Energy Technology Data Exchange (ETDEWEB)

    Owusu-Bennoah, E. [Department of Soil Science, University of Ghana, Legon, Accra (Ghana); Zapata, F. [International Atomic Energy Agency, Vienna (Austria)]. E-mail: F.Zapata@iaea.org; Fardeau, J.C. [Departement Environnement et Agronomie, INRA, Versailles (France)

    2002-05-15

    Phosphorus deficiency is one of the major constraints for normal plant growth and crop yields in the acid soils of Ghana and therefore addition of P inputs is required for sustainable crop production. This is often difficult, if not impossible for small-scale farmers due to the high cost of mineral P fertilizers and limited access to fertilizer supplies. Direct application of finely ground phosphate rocks (PRs) and their modified forms have been recommended as alternatives for P fertilization. The direct application of the natural and modified PRs to these acid soils implies the need to predict their agronomic effectiveness of the PRs in the simplest and most cost-effective manner. In this study the classical greenhouse pot experiment was compared to the {sup 32}P isotopic kinetics laboratory method for evaluating the agronomic effectiveness of natural and modified Togo PR in six highly weathered Oxisols from southwest Ghana. In the {sup 32}P isotopic kinetics laboratory experiment the six soil samples were each fertilised at the rate of 50 mg P kg{sup -1} soil in the form of triple superphosphate (TSP), Togo PAPR-50%, and Togo PR, respectively. Controls without P amendment were also included. Isotopic exchange kinetics experiments were carried out on two sets of samples, immediately after P fertilizer additions (without incubation) and after 6 weeks of incubation under wet conditions and at a room temperature of 25 deg C. In the greenhouse pot experiment, P fertilizers in the form of Togo PR, Togo PAPR, Mali PR and TSP were each applied to the six soils at rates equivalent to 0, 30, 60, and 120 kg P ha{sup -1}, respectively. The P fertilizers were mixed with the soils and maize (Zea mays L.) variety Obatanpa was grown for 42 days before harvest. The isotopic kinetics data of the control samples indicated that 5 of the studied soils had very low P fertility status as reflected by their low P concentrations in solution (C{sub P}<0.02 mg P l{sup -1}) and low

  9. Conversion of Marine Structures to Calcium Phosphate Materials: Mechanisms of Conversion Using Two Different Phosphate Solutions

    OpenAIRE

    Macha, Innocent J.; Grossin, David; Ben-Nissan, Besim

    2016-01-01

    International audience; Marine structure, coralline materials were converted to calcium phosphate using twodifferent phosphate solutions. The aim was to study the conversion mechanisms under acidic andbasic environment at moderate conditions of temperature. Crystal growth and morphology ofconverted corals were characterized by XRD and SEM respectively. The results suggested thatunder acidic conditions (H3PO4), dissolution and precipitation control and direct the crystalformation and morpholog...

  10. Chloroquine Phosphate Oral

    Science.gov (United States)

    Chloroquine phosphate is in a class of drugs called antimalarials and amebicides. It is used to prevent and treat ... Chloroquine phosphate comes as a tablet to take by mouth. For prevention of malaria in adults, one dose is ...

  11. Glucose-6-phosphate dehydrogenase

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a protein that helps red ...

  12. Stimulation of d- and l-lactate dehydrogenases transcriptional levels in presence of diammonium hydrogen phosphate resulting to enhanced lactic acid production by Lactobacillus strain.

    Science.gov (United States)

    Singhvi, Mamata; Zendo, Takeshi; Iida, Hiroshi; Gokhale, Digambar; Sonomoto, Kenji

    2017-08-08

    The present study revealed the effect of nitrogen sources on lactic acid production and stimulation of d- and l-lactate dehydrogenases (LDH) of parent Lactobacillus lactis NCIM 2368 and its mutant RM2-24 generated after UV mutagenesis. Both the parent and mutant strains were evaluated for d-lactic acid production in control and modified media. The modified media did not show remarkable effect on lactic acid production in case of parent whereas mutant exhibited significant enhancement in d-lactic acid production along with the appearance of l-lactic acid in the broth. Both LDH activities and specific activities were found to be higher in mutant than the parent strain. These results suggested that the diammonium hydrogen phosphate in modified media triggered the expression of LDH genes leading to enhanced lactic acid production. This observation has been proved by studying the expression levels of d- and l-LDH genes of parent and mutant in control and modified media using quantitative RT-PCR technique. In case of mutant, the transcriptional levels of d-LDH and l-LDH increased ∼17 fold and ∼1.38 fold respectively in modified medium compared to the values obtained with control medium. In case of parent, no significant change in transcriptional levels of d- and l-LDH was found when the cells were grown in either control medium or modified medium. This study suggested that the mutant, RM2-24 has l-LDH gene which is expressed in presence of (NH4)2HPO4 resulting in l-lactic acid production. Co-production of l-lactic acid in d-lactic acid fermentation may be detrimental in the PLA production. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  13. Comparative genetic analysis of Arabidopsis purple acid phosphatases AtPAP10, AtPAP12, and AtPAP26 provides new insights into their roles in plant adaptation to phosphate deprivation

    Institute of Scientific and Technical Information of China (English)

    Liangsheng Wang; Shan Lu; Ye Zhang; Zheng Li; Xiaoqiu Du; Dong Liu

    2014-01-01

    Induction and secretion of acid phosphatases (APases) is thought to be an adaptive mechanism that helps plants survive and grow under phosphate (Pi) deprivation. In Arabidopsis, there are 29 purple acid phosphatase (AtPAP) genes. To systematical y investigate the roles of different AtPAPs, we first identified knockout or knock-down T-DNA lines for al 29 AtPAP genes. Using these atpap mutants combined with in-gel and quantitative APase enzyme assays, we demonstrated that AtPAP12 and AtPAP26 are two major intracellular and secreted APases in Arabidopsis while AtPAP10 is mainly a secreted APase. On Pi-deficient (P-) medium or P-medium supplemented with the organophosphates ADP and fructose-6-phosphate (Fru-6-P), growth of atpap10 was significantly reduced whereas growth of atpap12 was only moderately reduced, and growth of atpap26 was nearly equal to that of the wild type (WT). Overexpression of the AtPAP12 or AtPAP26 gene, however, caused plants to grow better on P-or P- medium supplemented with ADP or Fru-6-P. Interest-ingly, Pi levels are essential y the same for the WT and overexpressing lines, although these two types of plants have significantly different growth phenotypes. These results suggest that the APases may have other roles besides enhancing internal Pi recycling or releasing Pi from external organophosphates for plant uptake.

  14. Lipopolysaccharides from Serratia marcescens possess one or two 4-amino-4-deoxy-L-arabinopyranose 1-phosphate residues in the lipid A and D-glycero-D-talo-oct-2-ulopyranosonic acid in the inner core region.

    Science.gov (United States)

    Vinogradov, Evgeny; Lindner, Buko; Seltmann, Guntram; Radziejewska-Lebrecht, Joanna; Holst, Otto

    2006-08-25

    The carbohydrate backbones of the core-lipid A region were characterized from the lipopolysaccharides (LPSs) of Serratia marcescens strains 111R (a rough mutant strain of serotype O29) and IFO 3735 (a smooth strain not serologically characterized but possessing the O-chain structure of serotype O19). The LPSs were degraded either by mild hydrazinolysis (de-O-acylation) and hot 4 M KOH (de-N-acylation), or by hydrolysis in 2 % aqueous acetic acid, or by deamination. Oligosaccharide phosphates were isolated by high-performance anion-exchange chromatography. Through the use of compositional analysis, electrospray ionization Fourier transform mass spectrometry, and 1H and 13C NMR spectroscopy applying various one- and two-dimensional experiments, we identified the structures of the carbohydrate backbones that contained D-glycero-D-talo-oct-2-ulopyranosonic acid and 4-amino-4-deoxy-L-arabinose 1-phosphate residues. We also identified some truncated structures for both strains. All sugars were D-configured pyranoses and alpha-linked, except where stated otherwise.

  15. 烷醇酰胺磷酸酯表面活性剂的缓蚀性能%PERFORMANCE STUDY OF A SERIES OF FATTY ACID DIETHANOLAMINE PHOSPHATE AS CORROSION INHIBITORS

    Institute of Scientific and Technical Information of China (English)

    郑延成; 侯玲玲; 李卫晨子; 陈武

    2012-01-01

    betaine; oleic aicd; viscoelastic surfactantphosphate were prepared from fatty acids (myristic acid, hexadecanoic acid and stearic acid) ,diethano-lamine, phosphorous pentoxide and diethanolamine through acylating, phosphating and neutralizing reactions. Their surface activity was determined with different concentrations of products, and their inhibition efficiency against corrosion of carbon steel A3 in synthetic brine were investigated by weight loss measurement and polarization curves method. The experimental results showed that cmc of myristic acid diethanolamide phosphate(C14 N) , hexadecanoic acid diethanolamide phosphate(C16 N) and stearic acid diethanolamide phosphate(C18N) are 50, 50 and 30 mg/L, respectively, and their ycmcs were between 25 -29 mN/m. The results showed that C16N had a great corrosion inhibition, with the inhibition efficiency by polarization curve being 71. 7% at the amount of 100 mg/L, and the corrosion rate by static weight loss being 0. 071 6 mm/a at 50 ℃ within 4 d with the simulated water, which meets the requirement of for the injection water in oilfield. The corrosion inhibition mechanism was discussed based on the molecular structure.%以十四酸、十六酸和硬脂酸为原料与二乙醇胺反应合成了脂肪酸烷醇酰胺,经磷酸化反应及醇胺中和反应后制备了3种脂肪酸烷醇酰胺磷酸酯盐表面活性剂.测试了产物的组成及表面活性,电化学法和失重法考察了产物在矿化水中的防腐性能并与其他缓蚀剂进行了对比.结果表明,脂肪酸碳数为C14、C16、C18的磷酸酯盐(C14N、C16N和C18 N)的临界胶团浓度(cmc)分别为50~30 mg/L,对应于cmc的表面张力(γcmc)分别为27.31,24.57和27.65 mN/m;电化学法和失重法均表明随着脂肪酸碳数的增加,缓蚀性能先增加后降低.C16N具有较好的缓蚀性能,C14N次之,C18N最差.在模拟盐水中加入100 mg/L的产物C16N时,极化缓蚀率可以达到71.7%,50℃、4d时失

  16. Effects of inositol phosphates on mineral utilization

    Energy Technology Data Exchange (ETDEWEB)

    Tao, S.H.; Fox, M.R.S.; Phillippy, B.Q.; Fry, B.E. Jr.; Johnson, M.L.; Johnston, M.R.

    1986-03-05

    The present study was designed to compare the effects of inositol tri-, tetra-, and pentaphosphate (IP3, IP4, and IP5) with those of phytic acid (IP6) on growth, development and mineral utilization of young quail. Day-old Japanese quail were fed a purified casein-gelatin control diet containing 20 ppm Zn with 0 or 8.33 mmoles/kg of each inositol phosphate, corresponding to 0.55% of IP6, for a week. As compared with controls, IP6 caused reduced body weight, poor feathering, severe perosis, decreased tibia Zn and ash, and decreased pancreas Zn and liver Mn. IP5 produced all the same adverse effects and tissue mineral changes as those by phytic acid, whereas birds fed IP3 or IP4 were normal. Moreover, IP3 and IP4 caused an increased tibia weight and ash. None of the above effects was produced by feeding inositol or inorganic phosphate. In a second experiment, the inositol phosphates were fed at either 8.33 or 16.66 mmoles/kg diet. Doubling inositol phosphate levels resulted in similar effects as those observed previously. Additionally, IP4 decreased pancreas Zn and IP3 increased tibia Zn. These results indicate that unlike IP6 and IP5, inositol phosphates with 4 or fewer phosphate groups, which can arise from hydrolysis of phytic acid during food processing, have very minor adverse effects but may be beneficial for bone mineralization.

  17. Maize endophytic bacteria as mineral phosphate solubilizers.

    Science.gov (United States)

    de Abreu, C S; Figueiredo, J E F; Oliveira, C A; Dos Santos, V L; Gomes, E A; Ribeiro, V P; Barros, B A; Lana, U G P; Marriel, I E

    2017-02-16

    In the present study, we demonstrated the in vitro activity of endophytic phosphate-solubilizing bacteria (PSB). Fifty-five endophytic PSB that were isolated from sap, leaves, and roots of maize were tested for their ability to solubilize tricalcium phosphate and produce organic acid. Partial sequencing of the 16S rRNA-encoding gene showed that the isolates were from the genus Bacillus and different species of Enterobacteriaceae. The phosphate solubilization index on solid medium and phosphate solubilization in liquid medium varied significantly among the isolates. There was a statistically significant difference (P ≤ 0.05) for both, the values of phosphate-solubilizing activity and pH of the growth medium, among the isolates. Pearson correlation was statistically significant (P ≤ 0.05) between P-solubilization and pH (R = -0.38), and between the gluconic acid production and the lowering of the pH of the liquid medium at 6 (R = 0.28) and 9 days (R = 0.39). Gluconic acid production was prevalent in all the PSB studied, and Bacillus species were most efficient in solubilizing phosphate. This is the first report on the characterization of bacterial endophytes from maize and their use as potential biofertilizers. In addition, this may provide an alternative strategy for improving the phosphorus acquisition efficiency of crop plants in tropical soils.

  18. Research and engineering assessment of biological solubilization of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, R.D.; McIlwain, M.E.; Losinski, S.J.; Taylor, D.D.

    1993-03-01

    This research and engineering assessment examined a microbial phosphate solubilization process as a method of recovering phosphate from phosphorus containing ore compared to the existing wet acid and electric arc methods. A total of 860 microbial isolates, collected from a range of natural environments were tested for their ability to solubilize phosphate from rock phosphate. A bacterium (Pseudomonas cepacia) was selected for extensive characterization and evaluation of the mechanism of phosphate solubilization and of process engineering parameters necessary to recover phosphate from rock phosphate. These studies found that concentration of hydrogen ion and production of organic acids arising from oxidation of the carbon source facilitated microbial solubilization of both pure chemical insoluble phosphate compounds and phosphate rock. Genetic studies found that phosphate solubilization was linked to an enzyme system (glucose dehydrogenase). Process-related studies found that a critical solids density of 1% by weight (ore to liquid) was necessary for optimal solubilization. An engineering analysis evaluated the cost and energy requirements for a 2 million ton per year sized plant, whose size was selected to be comparable to existing wet acid plants.

  19. Clindamycin lotion alone versus combination lotion of clindamycin phosphate plus tretinoin versus combination lotion of clindamycin phosphate plus salicylic acid in the topical treatment of mild to moderate acne vulgaris: A randomized control trial

    Directory of Open Access Journals (Sweden)

    NilFroushzadeh Mohammad

    2009-01-01

    Full Text Available Background: Acne vulgaris is a common skin disease that affects 85% to 100% of people at some time during their lives. It is characterized by noninflammatory follicular papules or comedones and by inflammatory papules, pustules, and nodules in its more severe forms. Aims: To compare the efficacy of combination treatment of clindamycin+salicylic acid, versus clindamycin+tretinoin versus clindamycin alone in the treatment of the mild-to-moderate acne vulgaris. Methods: This was a single-blinded, randomized clinical trial.Forty-two female patients (age range: 15-25 years with mild-to-moderate acne vulgaris were selected randomly and subsequently randomized to 3 groups. Group A patients were treated with 1% clindamycin lotion (C lotion twice daily. Group B patients were treated with 1% clindamycin+0.025% tretinoin lotion once nightly (CT lotion. Group C patients were treated with 1% clindamycin+2% salicylic acid lotion twice daily (CS lotion for 12 weeks. For comparison of efficacy of these treatments, and regarding the skewed distribution of the data, Kruskal-Wallis Test and Mann-Whitney U test were used. SPSS software was used for statistical analysis. Results: There was a significant difference between 3 types of treatment in the respect of the total lesion count (TLC improvement ( P = 0.039. The efficacy of treatment on Acne Severity Index (ASI was maximum for CS lotion (81.80% reduction in ASI. CT lotion reduced ASI by as much as 73.73% during 12 weeks of treatment. The efficacy of C lotion was calculated to be 37.87% in the reduction of ASI. Conclusions: Our data suggested that the efficacy of CS lotion was significantly more than C lotion with respect to the TLC and ASI, although there was no significant difference between CS and CT lotion.

  20. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose 5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...... enzymes were dependent on the metal ion present, suggesting a function of the investigated aspartic acid residues both in the binding of ribose 5-phosphate, possibly via a divalent metal ion, and in the interaction with a divalent metal ion during catalysis...

  1. Cloning and characterization of a glucose 6-phosphate/phosphate translocator from Oryza sativa

    Institute of Scientific and Technical Information of China (English)

    姜华武; 佃蔚敏; 刘非燕; 吴平

    2003-01-01

    Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator (GPT) was isolated from a cDNA library of immature seeds of rice and named as OsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression of OsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported via GPT can be used for starch biosynthesis in rice nongreen plastids.

  2. Phosphate solubilizing bacteria and their role in plant growth promotion.

    Science.gov (United States)

    Rodríguez, H; Fraga, R

    1999-10-01

    The use of phosphate solubilizing bacteria as inoculants simultaneously increases P uptake by the plant and crop yield. Strains from the genera Pseudomonas, Bacillus and Rhizobium are among the most powerful phosphate solubilizers. The principal mechanism for mineral phosphate solubilization is the production of organic acids, and acid phosphatases play a major role in the mineralization of organic phosphorous in soil. Several phosphatase-encoding genes have been cloned and characterized and a few genes involved in mineral phosphate solubilization have been isolated. Therefore, genetic manipulation of phosphate-solubilizing bacteria to improve their ability to improve plant growth may include cloning genes involved in both mineral and organic phosphate solubilization, followed by their expression in selected rhizobacterial strains. Chromosomal insertion of these genes under appropriate promoters is an interesting approach.

  3. Factors determining rock phosphate solubilization by microorganisms isolated from soil.

    Science.gov (United States)

    Nahas, E

    1996-11-01

    Forty two soil isolates (31 bacteria and 11 fungi) were studied for their ability to solubilize rock phosphate and calcium phosphate in culture medium. Eight bacteria and 8 fungi possessed solubilizing ability. Pseudomonas cepacia and Penicillium purpurogenum showed the highest activity. There was a correlation between final pH value and titratable acidity (r=-0.29 to -0.87) and between titratable acidity and soluble phosphate (r=0.22 to 0.99). Correlation values were functions of insoluble phosphate and of the group of microorganisms considered. A high correlation was observed between final pH and soluble phosphate only for the rock phosphates inoculated with the highest concentration of solubilizing bacteria (r=-0.73 to -0.98).

  4. Discussion about magnesium phosphating

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-07-01

    Full Text Available The paper describes results from recently published research focused on production of non-conventional magnesium phosphate Mg3(PO42・4H2O – bobierrite, or MgHPO4・3H2O – newberyite coating for both magnesium alloys and/or mild steel. This new kind of coating is categorized in the context of current state of phosphating technology and its potential advantages and crystal structure is discussed. At the same time, the suitable comparison techniques for magnesium phosphate coating and conventional zinc phosphate coating are discussed.

  5. Rock Phosphate Solubilization Mechanisms of One Fungus and One Bacterium

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-mei; ZHAO Xiao-rong; ZHAO Zi-juan; LI Bao-guo

    2002-01-01

    Many microorganisms can dissolve the insoluble phosphates like apatite. However, the mechanisms are still not clear. This study was an attempt to investigate the mechanisms of rock phosphate solubilization by an Aspergillus 2TCiF2 and an Arthrobacter1TCRi7. The results indicated that the fungus produced a large amount of organic acids, mainly oxalic acid. The total quantity of the organic acids produced by the fungus was 550 times higher than that by the bacterium. Different organic acids had completely different capacities to solubilize the rock. Oxalic acid and citric acid had stronger capacity to dissolve the rock than malic acid, tartaric acid, lactic acid, acetic acid, malonic acid and succinic acid. The fungus solubilized the rock through excreting both proton and organic acids. The rock solubilization of the bacterium depended on only proton.

  6. Biological Removal of Phosphate Using Phosphate Solubilizing Bacterial Consortium from Synthetic Wastewater: A Laboratory Scale

    Directory of Open Access Journals (Sweden)

    Dipak Paul

    2015-01-01

    Full Text Available Biological phosphate removal is an important process having gained worldwide attention and widely used for removing phosphorus from wastewater. The present investigation was aimed to screen the efficient phosphate solubilizing bacterial isolates and used to remove phosphate from synthetic wastewater under shaking flasks conditions. Pseudomonas sp. JPSB12, Enterobacter sp. TPSB20, Flavobacterium sp. TPSB23 and mixed bacterial consortium (Pseudomonas sp. JPSB12+Enterobacter sp. TPSB20+Flavobacterium sp. TPSB23 were used for the removal of phosphate. Among the individual strains, Enterobacter sp. TPSB20 was removed maximum phosphate (61.75% from synthetic wastewater in presence of glucose as a carbon source. The consortium was effectively removed phosphate (74.15-82.50% in the synthetic wastewater when compared to individual strains. The pH changes in culture medium with time and extracellular phosphatase activity (acid and alkaline were also investigated. The efficient removal of phosphate by the consortium may be due to the synergistic activity among the individual strains and phosphatase enzyme activity. The use of bacterial consortium in the remediation of phosphate contaminated aquatic environments has been discussed.

  7. Cloning of an Erwinia herbicola gene necessary for gluconic acid production and enhanced mineral phosphate solubilization in Escherichia coli HB101: nucleotide sequence and probable involvement in biosynthesis of the coenzyme pyrroloquinoline quinone.

    Science.gov (United States)

    Liu, S T; Lee, L Y; Tai, C Y; Hung, C H; Chang, Y S; Wolfram, J H; Rogers, R; Goldstein, A H

    1992-09-01

    Escherichia coli is capable of synthesizing the apo-glucose dehydrogenase enzyme (GDH) but not the cofactor pyrroloquinoline quinone (PQQ), which is essential for formation of the holoenzyme. Therefore, in the absence of exogenous PQQ, E. coli does not produce gluconic acid. Evidence is presented to show that the expression of an Erwinia herbicola gene in E. coli HB101(pMCG898) resulted in the production of gluconic acid, which, in turn, implied PQQ biosynthesis. Transposon mutagenesis showed that the essential gene or locus was within a 1.8-kb region of a 4.5-kb insert of the plasmid pMCG898. This 1.8-kb region contained only one apparent open reading frame. In this paper, we present the nucleotide sequence of this open reading frame, a 1,134-bp DNA fragment coding for a protein with an M(r) of 42,160. The deduced sequence of this protein had a high degree of homology with that of gene III (M(r), 43,600) of a PQQ synthase gene complex from Acinetobacter calcoaceticus previously identified by Goosen et al. (J. Bacteriol. 171:447-455, 1989). In minicell analysis, pMCG898 encoded a protein with an M(r) of 41,000. These data indicate that E. coli HB101(pMCG898) produced the GDH-PQQ holoenzyme, which, in turn, catalyzed the oxidation of glucose to gluconic acid in the periplasmic space. As a result of the gluconic acid production, E. coli HB101(pMCG898) showed an enhanced mineral phosphate-solubilizing phenotype due to acid dissolution of the hydroxyapatite substrate.

  8. Design and synthesis of conformationally constrained 3-(N-alkylamino)propylphosphonic acids as potent agonists of sphingosine-1-phosphate (S1P) receptors.

    Science.gov (United States)

    Yan, Lin; Hale, Jeffrey J; Lynch, Christopher L; Budhu, Richard; Gentry, Amy; Mills, Sander G; Hajdu, Richard; Keohane, Carol Ann; Rosenbach, Mark J; Milligan, James A; Shei, Gan-Ju; Chrebet, Gary; Bergstrom, James; Card, Deborah; Rosen, Hugh; Mandala, Suzanne M

    2004-10-01

    A series of conformationally constrained 3-(N-alkylamino)propylphosphonic acids were systematically synthesized and their activities as S1P receptor agonists were evaluated. Several pyrrolidine and cyclohexane analogs had S1P receptor profiles comparable to the acyclic lead compound, 3-(N-tetradecylamino)propylphosphonic acid (3), lowered circulating lymphocytes in mice after iv administration and were thus identified as being suitable for further investigations.

  9. CE-MS of antihistamines using nonvolatile phosphate buffer.

    Science.gov (United States)

    Chien, Chiu-Tang; Li, Fu-An; Huang, Ju-Li; Her, Guor-Rong

    2007-05-01

    Antihistamines were analyzed by CE-ESI-MS using phosphate buffer. The separation was performed in an acidic environment so that phosphate ions had a net velocity flowing toward the inlet reservoir instead of the ESI source. To further reduce the effect of ion suppression, the sodium ion in sodium phosphate was replaced with an ammonium ion. Furthermore, with the combination of reducing the concentration of acid added to the sheath liquid and the use of a low-flow interface, phosphoric acid could be added to the sheath liquid. Because of the use of the same counterion (phosphate ion) in running buffer and in sheath liquid, the separation integrity (resolution, elution order, and peak shape) was preserved. In addition, ion suppression was also greatly alleviated because a minimal amount of phosphate flowed into the ESI source.

  10. Zinc phosphating of 6061-Al alloy using REN as additive

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shenglin; ZHANG Xiaolin; ZHANG Mingming

    2008-01-01

    Zinc phosphate coating formed on 6061-Al alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy (SEM), after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate (REN). REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO43- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.

  11. Supplementation of medium with diammonium hydrogen phosphate enhanced the D-lactate dehydrogenase levels leading to increased D-lactic acid productivity.

    Science.gov (United States)

    Singhvi, Mamata; Jadhav, Akanksha; Gokhale, Digambar

    2013-10-01

    The production of D-lactic acid by Lactobacillus lactis RM2-24 was investigated using modified media to increase the efficiency of the fermentation process. The results indicated that the addition of 5 g/l peptone and 1 g/l (NH4)2HPO4 enhanced D-lactic acid production by 32%, as compared to that obtained from non supplemented media, with a productivity of 3.0 g/l/h. Lactate dehydrogenase (LDH) expression profile in these different media was studied which resulted in appearance of additional LDH isoform produced by cells when they were grown in HSYE supplemented with (NH4)2HPO4. The additional LDH appears to be L-LDH contributing to production of L-lactic acid in the fermented broth. This is totally new information in the lactic acid fermentation and could be very useful to industries engaged in D-lactic acid production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Adição de ácidos orgânicos e húmicos em Latossolos e adsorção de fosfato Addition of organic and humic acids to Latosols and phosphate adsorption effects

    Directory of Open Access Journals (Sweden)

    F. V. Andrade

    2003-12-01

    Full Text Available A matéria orgânica pode diminuir a adsorção/precipitação de fosfato (A/PP pela liberação de ácidos orgânicos, que competem pelos sítios de adsorção, ou pela formação de compostos com o fosfato na solução do solo e, ou, formação de complexos com Al e Fe, reduzindo a A/PP. O objetivo deste trabalho foi avaliar a redução na A/PP em Latossolos, pela adição de ácidos orgânicos: ácido cítrico (AC, oxálico (AO, salicílico (AS - e de ácidos húmicos (AH. Foram utilizadas amostras de um Latossolo Vermelho textura muito argilosa - (LV e um Latossolo Vermelho-Amarelo textura franco-argilo-arenosa - (LVA. Amostras de 2,5 cm³ de TFSA dos solos foram colocadas em erlenmeyer onde foram adicionados: fósforo (K2HPO4 e, ou, ácidos orgânicos ou húmicos, de acordo com a forma de aplicação (fosfato antes, junto e depois da aplicação do ácido, nas doses da relação molar ácido orgânico/P variando de 0 a 2:1. As doses dos ácidos húmicos variaram de 0 a 89,28 mg cm-3, equivalendo à adubação orgânica de 0 a 40 t ha-1 de material orgânico. O efeito dos ácidos orgânicos/ácidos húmicos na redução da A/PP nos dois solos seguiu a seguinte ordem: AC > AO > AH > AS. A forma de adição dos ácidos influenciou a A/PP em ambos os solos. No LV, a aplicação de fosfato e ácidos orgânicos ou ácidos húmicos juntos (FJA causou a maior redução na A/PP, indicando que deve ter ocorrido a ligação entre fosfato e ácidos. No LVA, a aplicação de fosfato depois dos ácidos orgânicos ou ácidos húmicos (FDA causou a maior redução na A/PP, indicando ter ocorrido bloqueio dos sítios de adsorção pelos ácidos.Organic matter can reduce P adsorption/precipitation (PA/P by: release of organic acids which compete for phosphate adsorption sites; trough the formation of P- compounds in the soil solution; and by building complexes with Fe and Al and thus decreasing PA/P. The aim of this study was to evaluate the PA/P in Oxisols

  13. Radioactivity of phosphate mineral products

    OpenAIRE

    Mitrović Branislava; Vitorović Gordana; Stojanović Mirjana; Vitorović Duško

    2011-01-01

    The phosphate industry is one of the biggest polluters of the environment with uranium. Different products are derived after processing phosphoric ore, such as mineral and phosphate fertilizers and phosphate mineral supplements (dicalcium-and monocalcium phosphate) for animal feeding. Phosphate mineral additives used in animal food may contain a high activity of uranium. Research in this study should provide an answer to the extent in which phosphate minera...

  14. {sup 26}Al-containing acidic and basic sodium aluminum phosphate preparation and use in studies of oral aluminum bioavailability from foods utilizing {sup 26}Al as an aluminum tracer

    Energy Technology Data Exchange (ETDEWEB)

    Yokel, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States) and Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0305 (United States)]. E-mail: ryokel@email.uky.edu; Urbas, Aaron A. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Lodder, Robert A. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States); Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Selegue, John P. [Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055 (United States); Florence, Rebecca L. [College of Pharmacy, 511C Pharmacy Building 725 Rose Street, University of Kentucky Medical Center, Lexington, KY 40536-0082 (United States)

    2005-04-01

    We synthesized {sup 26}Al-containing acidic and basic (alkaline) sodium aluminum phosphates (SALPs) which are FDA-approved leavening and emulsifying agents, respectively, and used them to determine the oral bioavailability of aluminum incorporated in selected foods. We selected applicable methods from published syntheses (patents) and scaled them down ({approx}3000- and 850-fold) to prepare {approx}300-400 mg of each SALP. The {sup 26}Al was incorporated at the beginning of the syntheses to maximize {sup 26}Al and {sup 27}Al equilibration and incorporate the {sup 26}Al in the naturally-occurring Al-containing chemical species of the products. Near infrared spectroscopy (NIR) and X-ray powder diffraction (XRD) were used to characterize the two SALP samples and some intermediate samples. Multi-elemental analysis (MEA) was used to determine Na, Al and P content. Commercial products were included for comparison. Satisfactory XRD analyses, near infrared spectra and MEA results confirmed that we synthesized acidic and basic SALP, as well as some of the syntheses intermediates. The {sup 26}Al-containing acidic and basic SALPs were incorporated into a biscuit material and a processed cheese, respectively. These were used in oral bioavailability studies conducted in rats in which the {sup 26}Al present in blood after its oral absorption was quantified by accelerator mass spectrometry. The results showed oral Al bioavailability from acidic SALP in biscuit was {approx}0.02% and from basic SALP in cheese {approx}0.05%, lower than our previous determination of Al bioavailability from drinking water, {approx}0.3%. Both food and water can appreciably contribute to the Al absorbed from typical human Al intake.

  15. 中低品位磷矿生产磷酸联产石膏晶须技术现状%Present Status of Technology for Co-Production of Phosphoric Acid and Gypsum Whiskers from Medium-and Low-Grade Phosphate Rock

    Institute of Scientific and Technical Information of China (English)

    石学勇; 王金铭

    2013-01-01

    阐述了中低品位磷矿生产磷酸联产石膏晶须工艺技术的意义,并介绍了该工艺技术的基本原理和应用前景.采用盐酸和硫酸萃取磷矿并添加活性添加剂提高磷矿萃取速度和磷矿分解率,分离酸不溶物和部分杂质(铁、铝、镁),然后采用硫酸脱钙获得石膏晶须和磷酸,为中低品位磷矿综合利用提供了一条可行的途径.%A description is given of the technology for the co-production of phosphoric acid and gypsum whiskers from medium- and low-grade phosphate rock and its significance, also the fundamental principles of the technology and prospects for its use. Hydrochloric acid and sulfuric acid react with phosphate rock with the addition of an active additive to increase the extraction rate and decomposition rate of the rock, the acid-insolubles and some impurities ( iron, aluminum and magnesium) are separated out, and then sulfuric acid is used for decalcification to obtain phosphoric acid and gypsum whiskers, thereby providing a feasible route for comprehensive utilization of medium-and low-grade phosphate rock.

  16. 磷肥副产物氟硅酸中氟硅资源综合利用技术综述%Overview of Technology of Comprehensive Utilization of Fluosilicic Acid from Byproducts of Phosphate Fertilizer

    Institute of Scientific and Technical Information of China (English)

    周绿山

    2015-01-01

    The fluosilicic acid is a byproduct from production of phosphate fertilizer, its recovery and utilization technology is developed gradually from producing sodium fluorosilicate only to production of white carbon black and other products.An overview is given of several new processes for production of white carbon black by fluosilicic acid and co-production of hydrogen fluoride, ammonium bifluoride, cryolite, sodium fluoride, and so on. The advantages and disadvantages of each process are summarized.%氟硅酸是磷肥生产过程中的副产物,其回收利用技术由仅能生产氟硅酸钠逐渐发展为可以生产白炭黑等产品。概述了多种由氟硅酸制备白炭黑联产氟化氢、氟化氢铵、冰晶石、氟化钠等新工艺,并简要总结了各工艺的优缺点。

  17. Changes in Soil Available Phosphorus, Leaf Phosphorus Content and Yield of Sword Bean (Canavalia ensiformis (L. DC. by Application of SP-36 and Phosphate Rock on Acid Upland Soil of East Lampung

    Directory of Open Access Journals (Sweden)

    Achmad Arivin Rivaie

    2015-01-01

    Full Text Available A glasshouse trial was performed to determine changes in phosphorus (P nutrition and the yield of sword bean (Canavalia ensiformis (L. DC. following the application of different rates and types of P fertilizer in an acid upland soil of East Lampung. Two different types of P fertilizer, namely SP-36 (total P = 36% and Phosphate Rock (PR (total P = 24.3%, particle size distribution = 75% <0.25 mm, 85% < 0.50 mm, 90% < 1.00 mm were used in the trial. For the treatment, each P fertilizer type consisted of four rates (0, 50, 100 and 150 mg P2O5 kg-1 soil that were arranged in a Completely Randomized Design with four replications. The results showed that the application of P fertilizers had significant effects on soil pH, soil plant-available P, the potential-P (HCl 25%, leaf N and P concentrations, the yield of sword bean. Increased rates of both forms of P fertilizer increased the soil pH values. As the soil used had low pH and very high exchangeable Al, hence, this result is most probably related to the addition of Ca2+ to the soil solution that resulted from the P fertiliser applied (liming effect, either from SP-36 (monocalcium phosphate or PR (flour apatite. There was no difference in soil available P concentration due to the different in P fertilizer types, indicating that 4 months after the fertilizer application, the relatively insoluble Phosphate Rock had the same P solubility with SP-36. Increased rates of both forms of P fertilizer increased the sword bean yield. For the application of 0 kg P2O5 ha-1, although sword bean crops had pods, but, they did not give any seed. Whereas, at the addition of P fertilizer at the rate of 50, 100, and 150 kg P2O5 ha-1 for both P fertilizer types, the crops were able to give the seeds in the pods.

  18. A survey for isoenzymes of glucosephosphate isomerase, phosphoglucomutase, glucose-6-phosphate dehydrogenase and 6-Phosphogluconate dehydrogenase in C3-, C 4-and crassulacean-acid-metabolism plants, and green algae.

    Science.gov (United States)

    Herbert, M; Burkhard, C; Schnarrenberger, C

    1979-01-01

    Two isoenzymes each of glucosephosphate isomerase (EC 5.3.1.9), phosphoglucomutase (EC 2.7.5.1), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.43) were separated by (NH4)2SO4 gradient solubilization and DEAE-cellulose ion-exchange chromatography from green leaves of the C3-plants spinach (Spinacia oleracea L.), tobacco (Nicotiana tabacum L.) and wheat (Triticum aestivum L.), of the Crassulacean-acid-metabolism plants Crassula lycopodioides Lam., Bryophyllum calycinum Salisb. and Sedum rubrotinctum R.T. Clausen, and from the green algae Chlorella vulgaris and Chlamydomonas reinhardii. After isolation of cell organelles from spinach leaves by isopyenic centrifugation in sucrose gradients one of two isoenzymes of each of the four enzymes was found to be associated with whole chloroplasts while the other was restricted to the soluble cell fraction, implying the same intracellular distribution of these isoenzymes also in the other species.Among C4-plants, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were found in only one form in corn (Zea mays L.), sugar cane (Saccharum officinarum L.) and Coix lacrymajobi L., but as two isoenzymes in Atriplex spongiosa L. and Portulaca oleracea L. In corn, the two dehydrogenases were mainly associated with isolated mesophyll protoplasts while in Atriplex spongiosa they were of similar specific activity in both mesophyll protoplasts and bundle-sheath strands. In all five C4-plants three isoenzymes of glucosephosphate isomerase and phosphoglucomutase were found. In corn two were localized in the bundle-sheath strands and the third one in the mesophyll protoplasts. The amount of activity of the enzymes was similar in each of the two cell fractions. Apparently, C4 plants have isoenzymes not only in two cell compartments, but also in physiologically closely linked cell types such as mesophyll and bundle-sheath cells.

  19. Sodium ascorbyl phosphate in topical microemulsions.

    Science.gov (United States)

    Spiclin, Polona; Homar, Miha; Zupancic-Valant, Andreja; Gasperlin, Mirjana

    2003-04-30

    Sodium ascorbyl phosphate is a hydrophilic derivative of ascorbic acid, which has improved stability arising from its chemical structure. It is used in cosmetic and pharmaceutical preparations since it has many favorable effects in the skin, the most important being antioxidant action. In order to achieve this, it has to be converted into free ascorbic acid by enzymatic degradation in the skin. In the present work, o/w and w/o microemulsions composed of the same ingredients, were selected as carrier systems for topical delivery of sodium ascorbyl phosphate. We showed that sodium ascorbyl phosphate was stable in both types of microemulsion with no significant influence of its location in the carrier system. To obtain liquid microemulsions appropriate for topical application, their viscosity was increased by adding thickening agents. On the basis of rheological characterization, 4.00% (m/m) colloidal silica was chosen as a suitable thickening agent for w/o microemulsions and 0.50% (m/m) xanthan gum for the o/w type. The presence of thickening agent and the location of sodium ascorbyl phosphate in the microemulsion influenced the in vitro drug release profiles. When incorporated in the internal aqueous phase, sustained release profiles were observed. This study confirmed microemulsions as suitable carrier systems for topical application of sodium ascorbyl phosphate.

  20. Dual mechanism of ion permeation through VDAC revealed with inorganic phosphate ions and phosphate metabolites.

    Science.gov (United States)

    Krammer, Eva-Maria; Vu, Giang Thi; Homblé, Fabrice; Prévost, Martine

    2015-01-01

    In the exchange of metabolites and ions between the mitochondrion and the cytosol, the voltage-dependent anion channel (VDAC) is a key element, as it forms the major transport pathway for these compounds through the mitochondrial outer membrane. Numerous experimental studies have promoted the idea that VDAC acts as a regulator of essential mitochondrial functions. In this study, using a combination of molecular dynamics simulations, free-energy calculations, and electrophysiological measurements, we investigated the transport of ions through VDAC, with a focus on phosphate ions and metabolites. We showed that selectivity of VDAC towards small anions including monovalent phosphates arises from short-lived interactions with positively charged residues scattered throughout the pore. In dramatic contrast, permeation of divalent phosphate ions and phosphate metabolites (AMP and ATP) involves binding sites along a specific translocation pathway. This permeation mechanism offers an explanation for the decrease in VDAC conductance measured in the presence of ATP or AMP at physiological salt concentration. The binding sites occur at similar locations for the divalent phosphate ions, AMP and ATP, and contain identical basic residues. ATP features a marked affinity for a central region of the pore lined by two lysines and one arginine of the N-terminal helix. This cluster of residues together with a few other basic amino acids forms a "charged brush" which facilitates the passage of the anionic metabolites through the pore. All of this reveals that VDAC controls the transport of the inorganic phosphates and phosphate metabolites studied here through two different mechanisms.

  1. Performance of pineapple slips inoculated with diazotrophic phosphate-solubilizing bacteria and rock phosphate

    Directory of Open Access Journals (Sweden)

    Lílian Estrela Borges Baldotto

    2014-06-01

    Full Text Available Besides fixing N2, some diazotrophic bacteria or diazotrophs, also synthesize organic acids and are able to solubilize rock phosphates, increasing the availability of P for plants. The application of these bacteria to pineapple leaf axils in combination with rock phosphate could increase N and P availability for the crop, due to the bacterial activity of biological nitrogen fixation and phosphate solubilization. The objectives of this study were: (i to select and characterize diazotrophs able to solubilize phosphates in vitro and (ii evaluate the initial performance of the pineapple cultivars Imperial and Pérola in response to inoculation with selected bacteria in combination with rock phosphate. The experiments were conducted at Universidade Estadual do Norte Fluminense Darcy Ribeiro, in 2009. In the treatments with bacteria the leaf contents of N, P and K were higher than those of the controls, followed by an increase in plant growth. These results indicate that the combined application of diazotrophic phosphate-solubilizing bacteria Burkholderia together with Araxá rock phosphate can be used to improve the initial performance of pineapple slips.

  2. Regulation of resin acid synthesis in Pinus densiflora by differential transcription of genes encoding multiple 1-deoxy-D-xylulose 5-phosphate synthase and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase genes.

    Science.gov (United States)

    Kim, Yeon-Bok; Kim, Sang-Min; Kang, Min-Kyoung; Kuzuyama, Tomohisa; Lee, Jong Kyu; Park, Seung-Chan; Shin, Sang-Chul; Kim, Soo-Un

    2009-05-01

    Pinus densiflora Siebold et Zucc. is the major green canopy species in the mountainous area of Korea. To assess the response of resin acid biosynthetic genes to mechanical and chemical stimuli, we cloned cDNAs of genes encoding enzymes involved in the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway (1-deoxy-d-xylulose 5-phosphate synthase (PdDXS), 1-deoxy-d-xylulose 5-phosphate reductoisomerase (PdDXR) and 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (PdHDR)) by the rapid amplification of cDNA ends (RACE) technique. In addition, we cloned the gene encoding abietadiene synthase (PdABS) as a marker for the site of pine resin biosynthesis. PdHDR and PdDXS occurred as two gene families. In the phylogenetic trees, PdDXSs, PdDXR and PdHDRs each formed a separate clade from their respective angiosperm homologs. PdDXS2, PdHDR2 and PdDXR were most actively transcribed in stem wood, whereas PdABS was specifically transcribed. The abundance of PdDXS2 transcripts in wood in the resting state was generally 50-fold higher than the abundance of PdDXS1 transcripts, and PdHDR2 transcripts were more abundant by an order of magnitude in wood than in other tissues, with the ratio of PdHDR2 to PdHDR1 transcripts in wood being about 1. Application of 1 mM methyl jasmonate (MeJA) selectively enhanced the transcript levels of PdDXS2 and PdHDR2 in wood. The ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 reached 900 and 20, respectively, on the second day after MeJA treatment, whereas the transcript level of PdABS increased twofold by 3 days after MeJA treatment. Wounding of the stem differentially enhanced the transcript ratios of PdDXS2 to PdDXS1 and PdHDR2 to PdHDR1 to 300 and 70, respectively. The increase in the transcript levels of the MEP pathway genes in response to wounding was accompanied by two orders of magnitude increase in PdABS transcripts. These observations indicated that resin acid biosynthesis activity, represented by PdABS transcription, was correlated

  3. Phosphate control in dialysis.

    Science.gov (United States)

    Cupisti, Adamasco; Gallieni, Maurizio; Rizzo, Maria Antonietta; Caria, Stefania; Meola, Mario; Bolasco, Piergiorgio

    2013-10-04

    Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease-mineral and bone disorder (CKD-MBD) management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive-convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P) mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200-300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source. Finally, boiling should be the preferred cooking procedure, because it induces food demineralization, including phosphate loss. The integrated approach outlined in this article should be actively adapted as a therapeutic alliance by clinicians, dieticians, and patients for an effective control of phosphate balance in dialysis patients.

  4. Method for Producing Chemically Bonded Phosphate Ceramics and for Stabilizing Contaminants Encapsulated therein Utilizing Reducing Agents

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dileep; Wagh, Arun S.; Jeong, Seung-Young

    1999-05-05

    Known phosphate ceramic formulations are improved and the ability to produce iron-based phosphate ceramic systems is enabled by the addition of an oxidizing or reducing step during the acid-base reactions that form the phosphate ceramic products. The additives allow control of the rate of the acid-base reactions and concomitant heat generation. In an alternate embodiment, waste containing metal anions is stabilized in phosphate ceramic products by the addition of a reducing agent to the phosphate ceramic mixture. The reduced metal ions are more stable and/or reactive with the phosphate ions, resulting in the formation of insoluble metal species within the phosphate ceramic matrix, such that the resulting chemically bonded phosphate ceramic product has greater leach resistance.

  5. Plant Growth Promotion Induced by Phosphate Solubilizing Endophytic Pseudomonas Isolates

    Directory of Open Access Journals (Sweden)

    Nicholas eOtieno

    2015-07-01

    Full Text Available The use of plant growth promoting bacterial inoculants as live microbial biofertilisers provides a promising alternative to chemical fertilisers and pesticides. Inorganic phosphate solubilisation is one of the major mechanisms of plant growth promotion by plant associated bacteria. This involves bacteria releasing organic acids into the soil which solubilise the phosphate complexes converting them into ortho-phosphate which is available for plant up-take and utilisation. The study presented here describes the ability of endophytic bacterial isolates to produce gluconic acid, solubilise insoluble phosphate and stimulate the growth of Pea plants (Pisum sativum. This study also describes the genetic systems within three of these endophyte isolates thought to be responsible for their effective phosphate solubilising abilities. The results showed that many of the endophytic isolates produced gluconic acid (14-169 mM and have moderate to high phosphate solubilisation capacities (~ 400-1300 mg L-1. When inoculated to Pea plants grown in sand/soil under soluble phosphate limiting conditions, the endophyte isolates that produced medium to high levels of gluconic acid also displayed enhanced plant growth promotion effects.

  6. 1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane and tris(methylphenyl) phosphate cause significant effects on development, mRNA expression, and circulating bile acid concentrations in chicken embryos

    Energy Technology Data Exchange (ETDEWEB)

    Crump, Doug, E-mail: doug.crump@ec.gc.ca [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Porter, Emily; Egloff, Caroline; Williams, Kim L.; Letcher, Robert J.; Gauthier, Lewis T. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Kennedy, Sean W. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5 (Canada)

    2014-06-15

    1,2-Dibromo-4-(1,2-dibromoethyl)-cyclohexane (DBE-DBCH; formerly abbreviated as TBECH) and tris(methylphenyl) phosphate (TMPP; formerly abbreviated as TCP) are additive flame retardants that are detected in the environment and biota. A recent avian in vitro screening study of 16 flame retardants identified DBE-DBCH and TMPP as important chemicals for follow-up in ovo evaluation based on their effects on cytotoxicity and mRNA expression in avian hepatocytes. In this study, technical mixtures of DBE-DBCH and TMPP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 54,900 ng/g and from 0 to 261,400 ng/g, respectively, to determine effects on pipping success, development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations. Both compounds were detectable in embryos at pipping and the β-DBE-DBCH isomer was depleted more rapidly than the α-isomer in tissue samples. DBE-DBCH had limited effects on the endpoints measured, with the exception of the up-regulation of two phase I metabolizing enzymes, CYP3A37 and CYP2H1. TMPP exposure caused embryonic deformities, altered growth, increased liver somatic index (LSI) and plasma bile acid concentrations, and altered mRNA expression levels of genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Overall, TMPP elicited more adverse molecular and phenotypic effects than DBE-DBCH albeit at concentrations several orders of magnitude greater than those detected in the environment. The increase in plasma bile acid concentrations was a useful phenotypic anchor as it was associated with a concomitant increase in LSI, discoloration of the liver tissue, and modulation of hepatic genes involved with xenobiotic and lipid metabolism. - Highlights: • DBE-DBCH and TMPP are not embryolethal to chicken embryos. • TMPP caused deformities, morphometric alterations, and increased plasma bile acids. • DBE-DBCH and TMPP altered mRNA levels

  7. [An experimental study on a slow-release complex with rifampicin-polylactic-co-glycolic acid-calcium 
phosphate cement].

    Science.gov (United States)

    Wu, Jianhuang; Ding, Zhou; Lei, Qing; Li, Miao; Liang, Yan; Lu, Tao

    2016-09-28

    目的:制备利福平(rifampicin,RFP)-聚乳酸-羟基乙酸(polylactic-co-glycolic acid,PLGA)-磷酸钙骨水泥(calcium phosphate cement,CPC)缓释复合体(RFP-PLGA-CPC复合体),并研究其理化性质及体外释药性能。方法:采用乳化-溶剂挥发法制备RFP-PLGA缓释微球。实验分为CPC组、包埋了RFP的CPC组(RFP-CPC组)、载有RFP的PLGA缓释微球与自固化CPC复合体组(RFP-PLGA-CPC复合体组)。测定3组材料的凝固时间﹑孔隙率。通过体外药物释放实验观察释药前后的抗压强度、断面形态的变化以及体外释药情况。结果:CPC组的凝固时间最短,RFP-PLGA-CPC复合体组的凝固时间最长。CPC组的孔隙率同RFP-CPC组比较,差异有统计学意义(P<0.05);CPC组和RFP-CPC组的孔隙率与RFP-PLGA-CPC复合体组比较,差异均有统计学意义(均P<0.01)。RFP-PLGA-CPC复合体组的抗压强度与CPC组比较,差异有统计学意义(P<0.01);而RFP-CPC组和CPC组之间的抗压强度随着时间的变化逐渐表现出显著性差异(3 d: P<0.05;30和60 d:P<0.01)。CPC组在降解过程中的抗压强度的变化不大。PLGA微球的大小均一,粒径基本在100~150 μm之间,微球的形态呈现出球体或是类球体,微球的表面圆润光滑,无杂质附着; CPC组的断面空隙在浸泡3 d直至60 d都没有明显变化;而RFP-CPC组的微结构变化亦不大,其断面均是小的微粒形成的;RFP-PLGA-CPC复合体组断面的孔隙明显增多,一直到60 d时PLGA微球逐渐消失,剩下空洞。RFP-PLGA-CPC复合体组无明显短时间内药物大量释放现象,60 d累计释药率达到近95%,将该复合体释药行为进行线性拟合,发现药物以恒速进行局部释放,符合零级动力学方程F=0.168×t。结论:RFP-PLGA-CPC复合体孔隙率显著高于CPC,能够持续缓慢释放有效抗结核药物,并能较长时间维持一定的力学强度。.

  8. The active centre of rabbit muscle triose phosphate isomerase. The site that is labelled by glycidol phosphate.

    Science.gov (United States)

    Miller, J C; Waley, S G

    1971-06-01

    1. Glycidol (2,3-epoxypropanol) phosphate is a specific irreversible inhibitor of rabbit muscle triose phosphate isomerase (EC 5.3.1.1); the site of attachment has now been studied. 2. The labelled enzyme was digested with pepsin and a modified peptide isolated. The sequence of the peptide is: Ala-Tyr-Glu-Pro-Val-Trp. 3. It is the glutamic acid residue in this peptide that is labelled: the peptide is thus a gamma-glutamyl ester derived from glycerol phosphoric acid. The same site is labelled by a mixture of glycidol and inorganic phosphate. 4. Kinetic and stereochemical features of these reactions are discussed.

  9. Solid state NMR study calcium phosphate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Miquel, J.L.; Facchini, L.; Legrand, A.P. (Laboratoire de Physique Quantique, Paris (France). CNRS, URA421, ESPCI); Rey, C. (CNRS, Toulouse (France). ENSC. Laboratoire de Physico-chimie des Solides); Lemaitre, J. (EPF Lausanne (France). Laboratoire de Technologie des Poudres)

    1990-04-01

    High-resolution {sup 31}P and {sup 1}H NMR spectra at 40 and 121 MHz {sup 31}P and 300 MHz {sup 1}H of synthetic and biological samples of calcium phosphates have been obtained by magic angle spinning (MAS) at spinning speeds up to 6.5 kHz, and high power proton decoupling. The samples include crystalline hydroxyapatite, a deficient hydroxyapatite characterized by a Ca/P atomic ratio of 1.5, a poorly crystallized hydroxyapatite, monetite, brushite, octacalcium phosphate, {beta}-tricalcium phosphate and rabbit femoral bone. The interactions between nuclei in unlike structures and the mobility of acid protons are discussed. (author). 11 refs.; 2 figs.; 1 tab.

  10. Zirconium phosphate binder for periclase refractories

    Energy Technology Data Exchange (ETDEWEB)

    Volceanov, E. [ICEM S.A., Bucharest (Romania). Metallurgical Research Inst.; Georgescu, M.; Volceanov, A. [Universitatea Politehnica, Bucharest (Romania). Faculty of Industrial Chemistry; Mihalache, F. [REAL S.A., Ploiesti (Romania)

    2002-07-01

    Present paper brings information concerning the physical-mechanical properties of some high thermal resistant composites with phosphate bonding obtained from periclase clinker as solid component and various zirconium phosphates solutions as liquid component: ZI, ZII and ZIII. All these solutions were prepared from hydrous zirconia and orthophosphoric acid. The batches corresponding to a weight ratio solid / liquid = 3 / 1, have shown a good hardening behavior at normal temperature, especially for the ZII binder. Such compositions exhibit a very good thermal-mechanical behavior in the temperature range 1400 C - 1750 C. X-ray diffraction and electronomicroscopy (TEM) analysis provided information concerning the evolution of phase composition and microstructure during heating of the thermal resistant specimens chemically bound with a zirconium phosphate binder. (orig.)

  11. Effect of Applying Phosphate-solubilizing Bacteria to Acid Purple Soil on Yield-increasing of Soybean%酸性紫色土施用溶磷菌对大豆的增产效应

    Institute of Scientific and Technical Information of China (English)

    王芳; 谢庭生

    2012-01-01

    酸性紫色土大豆施用溶磷菌(水剂)的试验结果表明:与常规施肥比较,土壤中有效磷含量提高16.04%;大豆植株分枝数、株高、每株有效结荚数明显增加;最低结荚位明显降低,百粒鲜豆重明显增加;大豆单产提高7.87%,纯收入显著增加,产量增加达极显著水平;对土壤无污染,生态效益好.%Applying phosphate-solubilizing bacteria (water) to acid purple soil where planted soybean to conduct experiment. The results showed that the content of available phosphor in soil increased by 16.04%; the branch number, the plant height, the effective pot-setting number per plant and the fresh weight of bean increased obviously; the lowest pod position reduced obviously, but the fresh weight of 100 beans increased significantly; unit yield of soybean increased by 7.87%, the pure income increased significantly, and the yield-increasing reached significant level; this treatment had no pollution on soil and has good ecological benefit.

  12. Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized β-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models.

    Science.gov (United States)

    Cao, Lu; Duan, Ping-Guo; Li, Xi-Lei; Yuan, Feng-Lai; Zhao, Ming-Dong; Che, Wu; Wang, Hui-Ren; Dong, Jian

    2012-01-01

    The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, β-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC). Quasistatic nonconstraining torques (maximum 1.5 NM) induced flexion, extension, lateral bending (±1.5 NM), and axial rotation (±1.5 NM) on 32 sheep cervical spines (C2-C5). The motion segment C3-C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic-Wego polyetheretherketone (PEEK) cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM) was calculated from the load-displacement curves. BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP) significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation. The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages.

  13. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose-5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    The three conserved aspartic acid residues of the 5-phospho-d-ribosyl a-1-diphosphate binding site (213-GRDCVLVDDMIDTGGT-228) of Escherichia coli phosphoribosyl diphosphate synthetase were studied by analysis of the mutant enzymes D220E, D220F, D221A, D224A, and D224S. The mutant enzymes showed...... an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...

  14. Effects of mutagenesis of aspartic acid residues in the putative phosphoribosyl diphosphate binding site of Escherichia coli phosphoribosyl diphosphate synthetase on metal ion specificity and ribose 5-phosphate binding

    DEFF Research Database (Denmark)

    Willemoës, Martin; Nilsson, Dan; Hove-Jensen, Bjarne

    1996-01-01

    The three conserved aspartic acid residues of the 5-phospho-D-ribosyl α-1-diphosphate binding site (213-GRDCVLVDDMIDTGGT-228) of Escherichia coli phosphoribosyl diphosphate synthetase were studied by analysis of the mutant enzymes D220E, D220F, D221A, D224A, and D224S. The mutant enzymes showed...... an increase in KM for ribose 5-phosphate in the presence of at least one of the divalent metal ions Mg2+, Mn2+, Co2+, or Cd2+, with the most dramatic changes revealed by the D220E and D220F enzymes in the presence of Co2+ and the D221A enzyme in the presence of Mn2+ or Co2+. The D220F and D221A enzymes both...... showed large decreases in Vapp in the presence of the various divalent metal ions, except for the D221A enzyme in the presence of Co2+. Vapp of the D220E enzyme was similar to that of the wild-type enzyme in the presence of Mg2+, Mn2+, or Cd2+, whereas the Vapp was increased in the presence of Co2+. Vapp...

  15. Inhibitory activity of phosphates on molds isolated from foods and food processing plants.

    Science.gov (United States)

    Suárez, V B; Frisón, L; de Basílico, M Z; Rivera, M; Reinheimer, J A

    2005-11-01

    Six commercial phosphates were evaluated for inhibition of the growth of 17 molds isolated from food sources. The assays were performed at neutral and natural (without pH adjustment) pH values, and the molds were streaked on plate count agar with added phosphates. Phosphate concentrations of 0.1, 0.3, 0.5, 1.0, and 1.5% (wt/vol) were used, and the MIC was determined. The resistance of molds to phosphates depended on the species. At a neutral pH, Aspergillus ochraceus and Fusarium proliferatum were resistant to all phosphates at all concentrations assayed, and Byssochlamys nivea, Aureobasidium pullulans, and Penicillium glabrum were most sensitive. The most inhibitory phosphates were those with chain lengths greater than 15 phosphate units and the highest sequestering power. At natural pH values (resulting from dissolving the phosphate in the medium), inhibitory activity changed dramatically for phosphates that produced alkaline or acidic pH in the medium. Phosphates with alkaline pH values (sodium tripolyphosphate of high solubility, sodium tripolyphosphate, and sodium neutral pyrophosphate) were much more inhibitory than phosphates at a neutral pH, but sodium acid pyrophosphate (acidic pH) had decreased inhibitory activity. The results indicate that some phosphates could be used in the food industry to inhibit molds linked to food spoilage.

  16. Phosphate control in dialysis

    Directory of Open Access Journals (Sweden)

    Cupisti A

    2013-10-01

    Full Text Available Adamasco Cupisti,1 Maurizio Gallieni,2 Maria Antonietta Rizzo,2 Stefania Caria,3 Mario Meola,4 Piergiorgio Bolasco31Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; 2Nephrology and Dialysis Unit, San Carlo Borromeo Hospital, Milan, Italy; 3Territorial Department of Nephrology and Dialysis, ASL Cagliari, Italy; 4Sant'Anna School of Advanced Studies, University of Pisa, Pisa, ItalyAbstract: Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease–mineral and bone disorder (CKD–MBD management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive–convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200–300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source

  17. [The solubilization of four insoluble phosphates by some microorganisms].

    Science.gov (United States)

    Zhao, Xiaorong; Lin, Qimei; Li, Baoguo

    2002-04-01

    Four insoluble phosphates of ferric phosphate (Fe-P), aluminum phosphate (Al-P), fluorapatite (FAP) and rock phosphate (RP) were used as a sole phosphorus resource for some phosphate-solubilizing microorganisms. It was found that there was significant difference in solubilizing these phosphates by the tested isolates. The fungi normally were more powerful than the bacteria in dissolving the phsophates. The microorganisms generally solubilized more phosphate when supplied with NO3- than with NH4+. However, the isolates of 2TCiF2 and 4TCiF6 had much higher capacity to solubilize FAP and Al-P respectively in NH4+ medium. Most of the isolates solubilized readily FAP and RP, and then Al-P. Ferric phosphate was the least soluble to these isolates. Only isolate 2TCiF2 showed strong ability to solubilize Fe-P. In particular, two Aspergillus sp. had much higher capacity of dissolving Fe-P when suppled with NO3-. The isolates of Evwinia sp. 4TCRi22 and Enterobacter sp. 1TCRi15 had higher capacity of solubilizing FAP. But two Arthrobacter sp. showed the highest activity in RP medium. It is supposed that complexion of organic acids with metals may be the main reason for these isolates to solubilize the phosphates. However, other chelant substances may be much more important for Enterobacter sp. and Erwinia sp. to release phosphorus from the phsphates.

  18. The Safety and Tolerability of 5-Aminolevulinic Acid Phosphate with Sodium Ferrous Citrate in Patients with Type 2 Diabetes Mellitus in Bahrain

    Directory of Open Access Journals (Sweden)

    Feryal Al-Saber

    2016-01-01

    Full Text Available Type 2 diabetes mellitus is prevalent especially in Gulf countries and poses serious long-term risks to patients. A multifaceted treatment approach can include nutritional supplements with antioxidant properties such as 5-aminolevulinic acid (5-ALA with sodium ferrous citrate (SFC. This prospective, randomized, single-blind, placebo-controlled, dose escalating pilot clinical trial assessed the safety of 5-ALA with SFC at doses up to 200 mg 5-ALA/229.42 mg SFC per day in patients living in Bahrain with type 2 diabetes mellitus that was uncontrolled despite the use of one or more antidiabetic drugs. Fifty-three patients (n=53 from 3 sites at one center were enrolled by Dr. Feryal (Site #01, Dr. Hesham (Site #02, and Dr. Waleed (Site #03 (n=35, 5-ALA-SFC; n=18, placebo. There was no significant difference in incidence of adverse events reported, and the most frequent events reported were gastrointestinal in nature, consistent with the known safety profile of 5-ALA in patients with diabetes. No significant changes in laboratory values and no difference in hypoglycemia between patients receiving 5-ALA and placebo were noted. Overall, the current results support that use of 5-ALA-SFC up to 200 mg per day taken as 2 divided doses is safe in patients taking concomitant oral antidiabetic medications and may offer benefits in the diabetic population. This trial is registered with ClinicalTrials.gov NCT02481141.

  19. The Safety and Tolerability of 5-Aminolevulinic Acid Phosphate with Sodium Ferrous Citrate in Patients with Type 2 Diabetes Mellitus in Bahrain

    Science.gov (United States)

    Al-Saber, Feryal; Aldosari, Waleed; Alselaiti, Mariam; Khalfan, Hesham; Kaladari, Ahmed; Khan, Ghulam; Harb, George; Rehani, Riyadh; Kudo, Sizuka; Koda, Aya; Tanaka, Tohru

    2016-01-01

    Type 2 diabetes mellitus is prevalent especially in Gulf countries and poses serious long-term risks to patients. A multifaceted treatment approach can include nutritional supplements with antioxidant properties such as 5-aminolevulinic acid (5-ALA) with sodium ferrous citrate (SFC). This prospective, randomized, single-blind, placebo-controlled, dose escalating pilot clinical trial assessed the safety of 5-ALA with SFC at doses up to 200 mg 5-ALA/229.42 mg SFC per day in patients living in Bahrain with type 2 diabetes mellitus that was uncontrolled despite the use of one or more antidiabetic drugs. Fifty-three patients (n = 53) from 3 sites at one center were enrolled by Dr. Feryal (Site #01), Dr. Hesham (Site #02), and Dr. Waleed (Site #03) (n = 35, 5-ALA-SFC; n = 18, placebo). There was no significant difference in incidence of adverse events reported, and the most frequent events reported were gastrointestinal in nature, consistent with the known safety profile of 5-ALA in patients with diabetes. No significant changes in laboratory values and no difference in hypoglycemia between patients receiving 5-ALA and placebo were noted. Overall, the current results support that use of 5-ALA-SFC up to 200 mg per day taken as 2 divided doses is safe in patients taking concomitant oral antidiabetic medications and may offer benefits in the diabetic population. This trial is registered with ClinicalTrials.gov NCT02481141.

  20. Drug-pyridoxal phosphate interactions.

    Science.gov (United States)

    Ebadi, M; Gessert, C F; Al-Sayegh, A

    1982-01-01

    phosphate. Some interesting relationships are pointed out between vitamin B6, picolinic acid, and zinc. It is postulated that the intestinal absorption of zinc is facilitated by picolinic acid, a metabolite of tryptophan. The derivation of picolinic acid from tryptophan depends on the action of the enzyme kynureninase, which is dependent on pyridoxal phosphate; therefore, the adequate absorption of zinc is indirectly dependent on an adequate supply of vitamin B6. The formation of pyridoxal phosphate, on the other hand, appears to be indirectly dependent on Zn2++ which activates pyridoxal kinase.(ABSTRACT TRUNCATED AT 400 WORDS)

  1. Activation of pyrophosphate:fructose-6-phosphate 1-phosphotransferase by fructose 2,6-bisphosphate stimulates conversion of hexose phosphates to triose phosphates but does not influence accumulation of carbohydrates in phosphate-deficient tobacco cells.

    Science.gov (United States)

    Fernie, Alisdair R; Roscher, Albrecht; Ratcliffe, R. George; Kruger, Nicholas J

    2002-02-01

    The aim of this work was to investigate the contribution of fructose 2,6-bisphosphate to the regulation of carbohydrate metabolism under phosphate stress. The study exploited heterotrophic tobacco callus lines expressing a modified mammalian 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase that increased the fructose 2,6-bisphosphate content of the tissue. The phosphate status of two transgenic and one untransformed cell line was perturbed by incubation with 2-deoxyglucose, a phosphate-sequestering agent, and by growth of callus on phosphate-depleted media. 31P-NMR spectroscopy confirmed that both treatments decreased cellular levels of inorganic phosphate and phosphorylated metabolites. Despite large decreases in the amounts of phosphate esters, UDPglucose and adenylates in response to phosphate deficiency, the fructose 2,6-bisphosphate content of each line was unaffected by 2-deoxyglucose and increased during growth on phosphate-limited media. Short-term treatment of callus with 2-deoxyglucose had only minor effects on the carbohydrate status of each line, whereas long-term phosphate deficiency caused an increase in starch and a decrease in soluble sugar content in both transgenic and control lines. There were no consistent differences between the three callus lines in metabolism of [U-14C]glucose in response to incubation with 2-deoxyglucose. In contrast, there was a decrease in partitioning of label into glycolytic products (particularly organic acids) in untransformed callus during growth on phosphate-depleted medium. This decrease was greatly attenuated in the transgenic lines with increased fructose 2,6-bisphosphate content. This suggests that the conversion of hexose phosphates to triose phosphates is constrained under phosphate-deficient conditions, and that this restriction can be relieved by activation of pyrophosphate:fructose-6-phosphate 1-phosphotransferase. However, since the transgenic and control lines did not differ in the extent to which the

  2. Mechanisms of phosphate removal from aqueous solution by blast furnace slag and steel furnace slag

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants ofk 6.372 and 1/n 1.739 for BFS, and ofk 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively.These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.

  3. Phosphate-responsive promoter of a Pichia pastoris sodium phosphate symporter.

    Science.gov (United States)

    Ahn, Jungoh; Hong, Jiyeon; Park, Myongsoo; Lee, Hyeokweon; Lee, Eungyo; Kim, Chunsuk; Lee, Joohwan; Choi, Eui-sung; Jung, Joon-ki; Lee, Hongweon

    2009-06-01

    To develop a functional phosphate-regulated promoter in Pichia pastoris, a phosphate-responsive gene, PHO89, which encodes a putative sodium (Na(+))-coupled phosphate symporter, was isolated. Sequencing analyses revealed a 1,731-bp open reading frame encoding a 576-amino-acid polypeptide with 12 putative transmembrane domains. The properties of the PHO89 promoter (P(PHO89)) were investigated using a bacterial lipase gene as a reporter in 5-liter jar fermentation experiments. P(PHO89) was tightly regulated by phosphate and was highly activated when the cells were grown in a phosphate-limited external environment. Compared to translation elongation factor 1alpha and the glyceraldehyde-3-phosphate dehydrogenase promoter, P(PHO89) exhibited strong transcriptional activity with higher specific productivity (amount of lipase produced/cell/h). Furthermore, a cost-effective and simple P(PHO89)-based fermentation process was developed for industrial application. These results demonstrate the potential for efficient use of P(PHO89) for controlled production of recombinant proteins in P. pastoris.

  4. A nucleophilic catalysis step is involved in the hydrolysis of aryl phosphate monoesters by human CT acylphosphatase.

    Science.gov (United States)

    Paoli, Paolo; Pazzagli, Luigia; Giannoni, Elisa; Caselli, Anna; Manao, Giampaolo; Camici, Guido; Ramponi, Giampietro

    2003-01-03

    Acylphosphatase, one of the smallest enzymes, is expressed in all organisms. It displays hydrolytic activity on acyl phosphates, nucleoside di- and triphosphates, aryl phosphate monoesters, and polynucleotides, with acyl phosphates being the most specific substrates in vitro. The mechanism of catalysis for human acylphosphatase (the organ-common type isoenzyme) was investigated using both aryl phosphate monoesters and acyl phosphates as substrates. The enzyme is able to catalyze phosphotransfer from p-nitrophenyl phosphate to glycerol (but not from benzoyl phosphate to glycerol), as well as the inorganic phosphate-H(2)18O oxygen exchange reaction in the absence of carboxylic acids or phenols. In short, our findings point to two different catalytic pathways for aryl phosphate monoesters and acyl phosphates. In particular, in the aryl phosphate monoester hydrolysis pathway, an enzyme-phosphate covalent intermediate is formed, whereas the hydrolysis of acyl phosphates seems a more simple process in which the Michaelis complex is attacked directly by a water molecule generating the reaction products. The formation of an enzyme-phosphate covalent complex is consistent with the experiments of isotope exchange and transphosphorylation from substrates to glycerol, as well as with the measurements of the Brønsted free energy relationships using a panel of aryl phosphates with different structures. His-25 involvement in the formation of the enzyme-phosphate covalent complex during the hydrolysis of aryl phosphate monoesters finds significant confirmation in experiments performed with the H25Q mutated enzyme.

  5. 脂肪酸烷醇酰胺磷酸酯表面活性剂的合成及性能研究%Synthesis and properties of fatty acid alkylolamide phosphate

    Institute of Scientific and Technical Information of China (English)

    郑延成; 黄倩; 梅平; 赖璐

    2011-01-01

    以C14~18的脂肪酸与二乙醇胺反应合成了系列脂肪酸烷醇酰胺,再经磷酸化反应及中和反应制备了6种脂肪酸烷醇酰胺磷酸酯盐表面活性剂.分别测定了各产物的组成及表面活性,考察了无机盐对表面张力(y)及临界胶束浓度(cmc)的影响,测试了不同碱中和产物水溶液与系列烷烃间的界面张力.结果表明,脂肪酸碳数为14,16和18的烷醇酰胺磷酸酯盐表面活性剂的cmc分别为50,50和30 mg/L,ycmc为26~31 mN·m-1;无机盐对产物的cmc影响不大;在质量分数为0.3%时,6种表面活性剂水溶液与正构烷烃形成最低界面张力的最小烷烃碳数为10~16,其中用NaOH中和得到的C14N与十二烷、十四烷以及C16N与十六烷均可达到超低界面张力,分别为0.0078,0.008 3和0.001 6mN ·m-1,用二乙醇胺中和得到的C14D也可与癸烷达到超低界面张力.%Three kinds of fatty acid ( myristic, palmitic and stearic acid) were separately reacted with diethanolamine, followed by phosphonating with phosphorous pentoxide and neutralizing with two kinds of neutralizing agent,sodium hydroxide and diethanolamine. The products were six kinds of anionic surfactant, fatty acid diethanolamide phosphate. Corresponding composition and surface activity of each product were measured. Influence of inorganic salts on the surface tension (y) and cmc of the products were examined. Interfacial tension between aqueous solution of the products prepared with different neutralizing agents and a series of paraffins was measured. Experimental results showed that cmc of products prepared from myristic, palmitic and stearic acid is 50,50 and 30 mg/L respectively; and their ycmc is within the range of 26 and 31 mN · m-1. Influence of inorganic salts on critical micelle concentration of the products is small. When the mass concentration of the products is 0. 3% , the minimum carbon number of paraffin to achieve lowest interfacial tension between aqueous

  6. 酸性条件下Al3+对苜蓿根瘤菌溶磷和分泌生长素能力的影响%Influences of Al3+ on Phosphate Solubilization and Auxin Secretion Abilities of Sinorhizobium meliloti under Acidic Conditions

    Institute of Scientific and Technical Information of China (English)

    张媚佳; 欧冰雷; 徐苏凌; 方勇; 徐根娣

    2011-01-01

    采用溶磷圈和Salkowski比色法,对酸性条件下铝对耐酸性能极优的两种根瘤菌溶磷和分泌生长素能力的影响进行了研究.结果表明,两种根瘤菌都具有较强的溶磷和分泌生长素的能力,且溶解无机磷的能力更强.在铝毒胁迫下,两菌株均表现出了一定的耐受性,随着铝离子浓度的增加,铝对溶磷和分泌生长素的能力抑制作用增强,相同条件下,菌株S1007较S1002具有更好的溶磷和分泌生长素的性能.%By means of phosphate solubilization ring and Salkowski colorimetry to study the influences of AP3+ on the phosphate solubilization and auxin secretion ability of two acid resistant varieties of rhizobium under acidic conditions. The results showed that the two varieties of rhizobium all have strong ability of phosphate solubilization and auxin secretion, and more apparent ability to dissolve inorganic phosphorus. The two strains all showed certain Al3+ tolerance under stress of Al3+ toxicity; the inhibitory effects of Al3+ on ability of phosphate solubilization and auxin secretion increases with increasing concentration of Al3+. Under the same conditions, strain SI007 showed a stronger ability of phosphate solubilization and auxin secretion in comparison with strain S1002.

  7. Study on technologic conditions for production of P-Mg compound fertilizer with high Mg phosphate gangue in mixed phosphoric acid and sulfuric acid%硫磷混酸分解高镁尾矿渣制取磷镁复合肥的工艺条件研究

    Institute of Scientific and Technical Information of China (English)

    胡宏; 徐德龙; 段永华; 解田

    2012-01-01

    介绍了以硫磷混酸和高镁磷尾矿粉为原料制备磷镁复合肥的工艺条件,研究了硫酸用量、磷酸用量、反应时间和反应温度对五氧化二磷、氧化镁转化率的影响.通过单因素实验得到最佳的工艺条件:磷酸用量为110 g、硫酸用量为15g、反应时间为20 min、反应温度为50℃.在此条件下,磷尾矿渣中五氧化二磷的转化率大于90%,氧化镁转化率大于80%.%Technologic conditions for production P-Mg compound fertilizer with mixed phosphoric acid and sulfuric acid and high Mg phosphate gangue as raw materials were introduced.Influences of factors,such as sulfuric acid dosage,phosphoric acid dosage,reaction time,and reaction temperature on conversion percents of P2O5 and MgO were studied.Through single factor experiment optimum technology conditions were obtained:phosphoric acid was 110 g,sulfuric acid was 15g,reaction time was 20 min.and reaction temperature was 50℃.Under the optimum conditions,conversion percent of P2O5 was more than 90% and conversion percent of MgO was over 80%.

  8. Phosphate inhibits in vitro Fe3+ loading into transferrin by forming a soluble Fe(III)-phosphate complex: a potential non-transferrin bound iron species.

    Science.gov (United States)

    Hilton, Robert J; Seare, Matthew C; Andros, N David; Kenealey, Zachary; Orozco, Catalina Matias; Webb, Michael; Watt, Richard K

    2012-05-01

    In chronic kidney diseases, NTBI can occur even when total iron levels in serum are low and transferrin is not saturated. We postulated that elevated serum phosphate concentrations, present in CKD patients, might disrupt Fe(3+) loading into apo-transferrin by forming Fe(III)-phosphate species. We report that phosphate competes with apo-transferrin for Fe(3+) by forming a soluble Fe(III)-phosphate complex. Once formed, the Fe(III)-phosphate complex is not a substrate for donating Fe(3+) to apo-transferrin. Phosphate (1-10mM) does not chelate Fe(III) from diferric transferrin under the conditions examined. Complexed forms of Fe(3+), such as iron nitrilotriacetic acid (Fe(3+)-NTA), and Fe(III)-citrate are not susceptible to this phosphate complexation reaction and efficiently deliver Fe(3+) to apo-transferrin in the presence of phosphate. This reaction suggests that citrate might play an important role in protecting against Fe(III), phosphate interactions in vivo. In contrast to the reactions of Fe(3+) and phosphate, the addition of Fe(2+) to a solution of apo-transferrin and phosphate lead to rapid oxidation and deposition of Fe(3+) into apo-transferrin. These in vitro data suggest that, in principle, elevated phosphate concentrations can influence the ability of apo-transferrin to bind iron, depending on the oxidation state of the iron.

  9. Research on Uncrystallized Phosphating Film

    Institute of Scientific and Technical Information of China (English)

    TANG En-jun; XING Ze-kuan

    2004-01-01

    This article excogitated a kind of uncrystallized phosphating film bears wearing capacity goodly by adding Ca2 + in normal phosphating solution. This technology is very useful to protect steel parts working in oil from abrasion.

  10. Glucose-6-phosphate dehydrogenase deficiency

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000528.htm Glucose-6-phosphate dehydrogenase deficiency To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a condition in which ...

  11. Glutamatergic or GABAergic neuron-specific, long-term expression in neocortical neurons from helper virus-free HSV-1 vectors containing the phosphate-activated glutaminase, vesicular glutamate transporter-1, or glutamic acid decarboxylase promoter.

    Science.gov (United States)

    Rasmussen, Morten; Kong, Lingxin; Zhang, Guo-rong; Liu, Meng; Wang, Xiaodan; Szabo, Gabor; Curthoys, Norman P; Geller, Alfred I

    2007-05-01

    Many potential uses of direct gene transfer into neurons require restricting expression to one of the two major types of forebrain neurons, glutamatergic or GABAergic neurons. Thus, it is desirable to develop virus vectors that contain either a glutamatergic or GABAergic neuron-specific promoter. The brain/kidney phosphate-activated glutaminase (PAG), the product of the GLS1 gene, produces the majority of the glutamate for release as neurotransmitter, and is a marker for glutamatergic neurons. A PAG promoter was partially characterized using a cultured kidney cell line. The three vesicular glutamate transporters (VGLUTs) are expressed in distinct populations of neurons, and VGLUT1 is the predominant VGLUT in the neocortex, hippocampus, and cerebellar cortex. Glutamic acid decarboxylase (GAD) produces GABA; the two molecular forms of the enzyme, GAD65 and GAD67, are expressed in distinct, but largely overlapping, groups of neurons, and GAD67 is the predominant form in the neocortex. In transgenic mice, an approximately 9 kb fragment of the GAD67 promoter supports expression in most classes of GABAergic neurons. Here, we constructed plasmid (amplicon) Herpes Simplex Virus (HSV-1) vectors that placed the Lac Z gene under the regulation of putative PAG, VGLUT1, or GAD67 promoters. Helper virus-free vector stocks were delivered into postrhinal cortex, and the rats were sacrificed 4 days or 2 months later. The PAG or VGLUT1 promoters supported approximately 90% glutamatergic neuron-specific expression. The GAD67 promoter supported approximately 90% GABAergic neuron-specific expression. Long-term expression was observed using each promoter. Principles for obtaining long-term expression from HSV-1 vectors, based on these and other results, are discussed. Long-term glutamatergic or GABAergic neuron-specific expression may benefit specific experiments on learning or specific gene therapy approaches. Of note, promoter analyses might identify regulatory elements that determine

  12. Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized β-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models

    Directory of Open Access Journals (Sweden)

    Cao L

    2012-11-01

    Full Text Available Lu Cao,1 Ping-Guo Duan,1 Xi-Lei Li,1 Feng-Lai Yuan,3 Ming-Dong Zhao,2 Wu Che,1 Hui-Ren Wang,1 Jian Dong11Department of Orthopedic Surgery, Zhongshan Hospital, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, China; 2Department of Orthopedic Surgery, Jinshan Hospital, Fudan University, Shanghai, China; 3Affiliated Third Hospital of Nantong University, Wuxi, ChinaPurpose: The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, β-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC.Methods: Quasistatic nonconstraining torques (maximum 1.5 NM induced flexion, extension, lateral bending (±1.5 NM, and axial rotation (±1.5 NM on 32 sheep cervical spines (C2–C5. The motion segment C3–C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic–Wego polyetheretherketone (PEEK cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM was calculated from the load-displacement curves.Results: BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation.Conclusion: The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages.Keywords: biomechanics, cervical spine, cages, bioabsorbable, sheep

  13. Glutamatergic or GABAergic neuron-specific, long-term expression in neocortical neurons from helper virus-free HSV-1 vectors containing the phosphate-activated glutaminase, vesicular glutamate transporter-1, or glutamic acid decarboxylase promoter

    Science.gov (United States)

    Rasmussen, Morten; Kong, Lingxin; Zhang, Guo-rong; Liu, Meng; Wang, Xiaodan; Szabo, Gabor; Curthoys, Norman P.; Geller, Alfred I.

    2009-01-01

    Many potential uses of direct gene transfer into neurons require restricting expression to one of the two major types of forebrain neurons, glutamatergic or GABAergic neurons. Thus, it is desirable to develop virus vectors that contain either a glutamatergic or GABAergic neuron-specific promoter. The brain/kidney phosphate-activated glutaminase (PAG), the product of the GLS1 gene, produces the majority of the glutamate for release as neurotransmitter, and is a marker for glutamatergic neurons. A PAG promoter was partially characterized using a cultured kidney cell line. The three vesicular glutamate transporters (VGLUTs) are expressed in distinct populations of neurons, and VGLUT1 is the predominant VGLUT in the neocortex, hippocampus, and cerebellar cortex. Glutamic acid decarboxylase (GAD) produces GABA; the two molecular forms of the enzyme, GAD65 and GAD67, are expressed in distinct, but largely overlapping, groups of neurons, and GAD67 is the predominant form in the neocortex. In transgenic mice, an ∼9 kb fragment of the GAD67 promoter supports expression in most classes of GABAergic neurons. Here, we constructed plasmid (amplicon) Herpes Simplex Virus (HSV-1) vectors that placed the Lac Z gene under the regulation of putative PAG, VGLUT1, or GAD67 promoters. Helper virus-free vector stocks were delivered into postrhinal cortex, and the rats were sacrificed 4 days or 2 months later. The PAG or VGLUT1 promoters supported ∼90 % glutamatergic neuron-specific expression. The GAD67 promoter supported ∼90 % GABAergic neuron-specific expression. Long-term expression was observed using each promoter. Principles for obtaining long-term expression from HSV-1 vectors, based on these and other results, are discussed. Long-term glutamatergic or GABAergic neuron-specific expression may benefit specific experiments on learning or specific gene therapy approaches. Of note, promoter analyses might identify regulatory elements that determine a glutamatergic or GABAergic

  14. Erythritol feeds the pentose phosphate pathway via three new isomerases leading to D-erythrose-4-phosphate in Brucella.

    Science.gov (United States)

    Barbier, Thibault; Collard, François; Zúñiga-Ripa, Amaia; Moriyón, Ignacio; Godard, Thibault; Becker, Judith; Wittmann, Christoph; Van Schaftingen, Emile; Letesson, Jean-Jacques

    2014-12-16

    Erythritol is an important nutrient for several α-2 Proteobacteria, including N2-fixing plant endosymbionts and Brucella, a worldwide pathogen that finds this four-carbon polyol in genital tissues. Erythritol metabolism involves phosphorylation to L-erythritol-4-phosphate by the kinase EryA and oxidation of the latter to L-3-tetrulose 4-phosphate by the dehydrogenase EryB. It is accepted that further steps involve oxidation by the putative dehydrogenase EryC and subsequent decarboxylation to yield triose-phosphates. Accordingly, growth on erythritol as the sole C source should require aldolase and fructose-1,6-bisphosphatase to produce essential hexose-6-monophosphate. However, we observed that a mutant devoid of fructose-1,6-bisphosphatases grew normally on erythritol and that EryC, which was assumed to be a dehydrogenase, actually belongs to the xylose isomerase superfamily. Moreover, we found that TpiA2 and RpiB, distant homologs of triose phosphate isomerase and ribose 5-phosphate isomerase B, were necessary, as previously shown for Rhizobium. By using purified recombinant enzymes, we demonstrated that L-3-tetrulose-4-phosphate was converted to D-erythrose 4-phosphate through three previously unknown isomerization reactions catalyzed by EryC (tetrulose-4-phosphate racemase), TpiA2 (D-3-tetrulose-4-phosphate isomerase; renamed EryH), and RpiB (D-erythrose-4-phosphate isomerase; renamed EryI), a pathway fully consistent with the isotopomer distribution of the erythrose-4-phosphate-derived amino acids phenylalanine and tyrosine obtained from bacteria grown on (13)C-labeled erythritol. D-erythrose-4-phosphate is then converted by enzymes of the pentose phosphate pathway to glyceraldehyde 3-phosphate and fructose 6-phosphate, thus bypassing fructose-1,6-bisphosphatase. This is the first description to our knowledge of a route feeding carbohydrate metabolism exclusively via D-erythrose 4-phosphate, a pathway that may provide clues to the preferential metabolism of

  15. Phosphate removal from wastewater using red mud.

    Science.gov (United States)

    Huang, Weiwei; Wang, Shaobin; Zhu, Zhonghua; Li, Li; Yao, Xiangdong; Rudolph, Victor; Haghseresht, Fouad

    2008-10-01

    Red mud, a waste residue of alumina refinery, has been used to develop effective adsorbents to remove phosphate from aqueous solution. Acid and acid-thermal treatments were employed to treat the raw red mud. The effects of different treatment methods, pH of solution and operating temperature on adsorption have been examined in batch experiments. It was found that all activated red mud samples show higher surface area and total pore volume as well as higher adsorption capacity for phosphate removal. The red mud with HCl treatment shows the highest adsorption capacity among all the red mud samples, giving adsorption capacity of 0.58 mg P/g at pH 5.5 and 40 degrees C. The adsorption capacity of the red mud adsorbents decreases with increase of pH. At pH 2, the red mud with HCl treatment exhibits adsorption of 0.8 mg P/g while the adsorption can be lowered to 0.05 mg P/g at pH 10. However, the adsorption is improved at higher temperature by increasing 25% from 30 to 40 degrees C. The kinetic studies of phosphate adsorption onto red mud indicate that the adsorption mainly follows the parallel first-order kinetics due to the presence of two acidic phosphorus species, H(2)PO(4)(-) and HPO(4)(2-). An analysis of the adsorption data indicates that the Freundlich isotherm provides a better fitting than the Langmuir model.

  16. Practical application of phosphate treatment

    Energy Technology Data Exchange (ETDEWEB)

    Caravaggio, Mike [Integrated Chemistry Solutions Pte. Ltd., Singapore (Singapore)

    2011-05-15

    Phosphate treatment has been applied to subcritical fossil power boilers for well over half a century, as well as being used frequently in heat recovery steam generators. The use of this treatment has evolved over the decades, with the operating sodium to phosphate ratio being the defining factor for the evolution of the treatment. The evolving prescribed sodium to phosphate ratios have been based on the scientific research results and operating experience available at the time, and in the latest EPRI Guidelines issued in 2004 are set at a minimum sodium to phosphate ratio of 3:1, with provision to add up to 1 mg . L{sup -1} of additional free caustic. The ratio limitation has always been set in an effort to minimize the potential for corrosion caused by the potential misapplication of the treatment. Typically, the operating ranges for phosphate treatments are depicted on an x-y plot with the x-axis the phosphate concentration and the y-axis the corrected pH value based on the maximum sodium to phosphate ratio allowed for by the treatment. These operating range plots define the theoretical operating range of a phosphate treatment. This paper briefly discusses the origin of the current phosphate control limits in the EPRI Guidelines, discusses phosphate chemistry, outlines the limitations involved when applying a phosphate treatment and provides additional practical guidance for overcoming these limitations and minimizing the potential for corrosion induced by the incorrect application of a phosphate treatment. (orig.)

  17. Approaches to Computer Modeling of Phosphate Hide-Out.

    Science.gov (United States)

    1984-06-28

    phosphate acts as a buffer to keep pH at a value above which acid corrosion occurs . and below which caustic corrosion becomes significant. Difficulties are...ionization of dihydrogen phosphate : HIPO - + + 1PO, K (B-7) H+ + - £Iao 1/1, (B-8) H , PO4 - + O- - H0 4 + H20 K/Kw (0-9) 19 * Such zero heat...OF STANDARDS-1963-A +. .0 0 0 9t~ - 4 NRL Memorandum Report 5361 4 Approaches to Computer Modeling of Phosphate Hide-Out K. A. S. HARDY AND J. C

  18. Immobilization of fission products in phosphate ceramic waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.; Wagh, A. [Argonne National Lab., IL (United States)

    1997-10-01

    Chemically bonded phosphate ceramics (CBPCs) have several advantages that make them ideal candidates for containing radioactive and hazardous wastes. In general, phosphates have high solid-solution capacities for incorporating radionuclides, as evidenced by several phosphates (e.g., monazites and apatites) that are natural analogs of radioactive and rare-earth elements. The phosphates have high radiation stability, are refractory, and will not degrade in the presence of internal heating by fission products. Dense and hard CBPCs can be fabricated inexpensively and at low temperature by acid-base reactions between an inorganic oxide/hydroxide powder and either phosphoric acid or an acid-phosphate solution. The resulting phosphates are extremely insoluble in aqueous media and have excellent long-term durability. CBPCs offer the dual stabilization mechanisms of chemical fixation and physical encapsulation, resulting in superior waste forms. The goal of this task is develop and demonstrate the feasibility of CBPCs for S/S of wastes containing fission products. The focus of this work is to develop a low-temperature CBPC immobilization system for eluted {sup 99}Tc wastes from sorption processes.

  19. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  20. Three-dimensionally Perforated Calcium Phosphate Ceramics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Porous calcium phosphate ceramics were produced by compression molding using a special mold followed by sintering. The porous calcium phosphate ceramics have three-dimensional and penetrated open pores380-400μm in diameter spaced at intervals of 200μm. The layers of the linear penetration pores alternately lay perpendicular to pore direction. The porosity was 59%-65% . The Ca/P molar ratios of the porous calcium phosphate ceramics range from 1.5 to 1.85. A binder containing methyl cellulose was most effective for preparing the powder compact among vinyl acetate, polyvinyl alcohol, starch, stearic acid, methyl cellulose and their mixtures. Stainless steel, polystyrene, nylon and bamboo were used as the long columnar male dies for the penetrated open pores. When polystyrene, nylon and bamboo were used as the long columnar male dies, the dies were burned out during the sintering process. Using stainless steel as the male dies with the removal of the dies before heat treatment resulted in a higher level of densification of the calcium phosphate ceramic.

  1. Cerebral metabolic and circulatory effects of 1,1,1-trichloroethane, a neurotoxic industrial solvent. 2. Tissue concentrations of labile phosphates, glycolytic metabolites, citric acid cycle intermediates, amino acids, and cyclic nucleotides.

    Science.gov (United States)

    Folbergrová, J; Hougaard, K; Westerberg, E; Siesjö, B K

    1984-01-01

    In order to obtain information on the mechanisms of neurotoxicity of 1,1,1-trichloroethane, rats maintained artificially ventilated on N2O:O2 (70:30) were exposed to a concentration of 1,1,1-trichloroethane of 8000 ppm, 43.7 mg L-1, that induces moderate ataxia in awake, spontaneously breathing animals. After 5 and 60 min of exposure, as well as after a 60-min recovery period following 60 min of exposure, the brain was frozen in situ and cortical tissue was assayed for phosphocreatine (PCr), + ATP, ADP, AMP, glycogen, glucose, pyruvate, lactate, citric acid cycle intermediates, associated amino acids, and cyclic nucleotides; in addition, purine nucleotides, nucleosides, and bases were assayed by HPLC techniques. Exposure of animals to 1,1,1-trichloroethane failed to alter blood glucose, lactate, and pyruvate concentrations. However, the solvent induced highly significant increases in tissue lactate and pyruvate concentrations that were also reflected in cisternal CSF. Associated with these changes were increases in all citric acid cycle intermediates except succinate, an increase in alanine concentration, and a rise in the glutamate/aspartate ratio. After 5 min, a small decrease in glycogen concentration also occurred. All these changes were reversed when the exposure was terminated. No changes were observed in tissue concentrations of purine nucleotides, nucleosides, and bases except for a small reduction of ATP concentration after 60 min of exposure, still noticeable after 60 min of recovery. Apart from a small reduction in cAMP concentration after 5 min of exposure, cyclic nucleotide concentrations did not change.

  2. Biomediated continuous release phosphate fertilizer

    Science.gov (United States)

    Goldstein, Alan H.; Rogers, Robert D.

    1999-01-01

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed.

  3. Selective separation of phosphate and fluoride from semiconductor wastewater.

    Science.gov (United States)

    Warmadewanthi, B; Liu, J C

    2009-01-01

    Hydrofluoric acid (HF) and phosphoric acid (H(3)PO(4)) are widely used in semiconductor industry for etching and rinsing purposes. Consequently, significant amount of wastewater containing phosphate and fluoride is generated. Selective separation of phosphate and fluoride from the semiconductor wastewater, containing 936 mg/L of fluoride, 118 mg/L of phosphate, 640 mg/L of sulfate, and 26.7 mg/L of ammonia, was studied. Chemical precipitation and flotation reactions were utilized in the two-stage treatment processes. The first-stage reaction involved the addition of magnesium chloride (MgCl(2)) to induce selective precipitation of magnesium phosphate. The optimal condition was pH 10 and molar ratio, [Mg(2 + )]/[(PO(4) (3-))], of 3:1, and 66.2% of phosphate was removed and recovered as bobierrite (Mg(3)(PO(4))(2).8H(2)O). No reaction was found between MgCl(2) and fluoride. Calcium chloride (CaCl(2)) was used in the second-stage reaction to induce precipitation of calcium fluoride and calcium phosphate. The optimum molar ratio, [Ca(2 + )]/[F(-)], was 0.7 at pH 10, and residual fluoride concentration of 10.7 mg/L and phosphate concentration of lower than 0.5 mg/L was obtained. Thermodynamic equilibrium was modeled with PHREEQC and compared with experimental results. Sodium dodecylsulfate (SDS) was an effective collector for subsequent solid-liquid removal via dispersed air flotation (DiAF). The study demonstrated that phosphate can be selectively recovered from the wastewater. Potential benefits include recovery of phosphate for reuse, lower required dosage of calcium for fluoride removal, and less amount of CaF(2) sludge.

  4. Hydrothermal method for preparing calcium phosphate monoliths

    Directory of Open Access Journals (Sweden)

    García Carrodeguas Raúl

    2003-01-01

    Full Text Available A new hydrothermal route for preparing biphasic calcium phosphate monoliths is proposed. Firstly, a slurry of beta-tricalcium phosphate/ortho-phosphoric acid (b-TCP/H3PO4 is cast into the desired final shape and size to obtain a block composed of dicalcium phosphate dihydrate (DCPD and b-TCP. This block is then treated in 1.0 M Na2HPO4 at 60 °C in order to hydrolyze the DCPD into Ca10-x(HPO4x(PO4 6-x(OH2-x (CDHA and Ca8H2(PO46 .5H2O (OCP. The result is a monolithic piece which preserves the initial shape and size, but which is composed instead of CDHA, OCP, and b-TCP. During the initial stage, when the pH is slightly alkaline, the product of DCPD hydrolysis is CDHA. However, when a neutral or slightly acidic pH is reached OCP is formed. Test samples processed by this method showed complete conversion of DCPD into CDHA and OCP after 112 h of hydrolysis, and with a compressive strength of 16.2 MPa, similar to cancellous bone.

  5. Calcium-phosphate-osteopontin particles for caries control

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Birkedal, Henrik; Olsen, Jakob

    2016-01-01

    Caries is caused by acid production in biofilms on dental surfaces. Preventing caries therefore involves control of microorganisms and/or the acid produced. Here, calcium-phosphate-osteopontin particles are presented as a new approach to caries control. The particles are made by co......-precipitation and designed to bind to bacteria in biofilms, impede biofilm build-up without killing the microflora, and release phosphate ions to buffer bacterial acid production if the pH decreases below 6. Analysis of biofilm formation and pH in a five-species biofilm model for dental caries showed that treatment......H always remained above 5.5. Hence, calcium-phosphate-osteopontin particles show potential for applications in caries control....

  6. Molecular Basis of Reduced Pyridoxine 5′-Phosphate Oxidase Catalytic Activity in Neonatal Epileptic Encephalopathy Disorder*

    OpenAIRE

    2009-01-01

    Mutations in pyridoxine 5′-phosphate oxidase are known to cause neonatal epileptic encephalopathy. This disorder has no cure or effective treatment and is often fatal. Pyridoxine 5′-phosphate oxidase catalyzes the oxidation of pyridoxine 5′-phosphate to pyridoxal 5′-phosphate, the active cofactor form of vitamin B6 required by more than 140 different catalytic activities, including enzymes involved in amino acid metabolism and biosynthesis of neurotransmitters. Our aim is to elucidate the mec...

  7. Aluminum phosphate ceramics for waste storage

    Science.gov (United States)

    Wagh, Arun; Maloney, Martin D

    2014-06-03

    The present disclosure describes solid waste forms and methods of processing waste. In one particular implementation, the invention provides a method of processing waste that may be particularly suitable for processing hazardous waste. In this method, a waste component is combined with an aluminum oxide and an acidic phosphate component in a slurry. A molar ratio of aluminum to phosphorus in the slurry is greater than one. Water in the slurry may be evaporated while mixing the slurry at a temperature of about 140-200.degree. C. The mixed slurry may be allowed to cure into a solid waste form. This solid waste form includes an anhydrous aluminum phosphate with at least a residual portion of the waste component bound therein.

  8. Synthesis of aryl phosphates based on pyrimidine and triazine scaffolds.

    Science.gov (United States)

    Courme, Caroline; Gresh, Nohad; Vidal, Michel; Lenoir, Christine; Garbay, Christiane; Florent, Jean-Claude; Bertounesque, Emmanuel

    2010-01-01

    The syntheses of the triazinyl-based bis-aryl phosphates 2 and 3, and of the aminopyrimidyl-based aryl phosphate 4 are described. Each compound contains a diaryl ether-phosphate structural motif. The synthetic route to bis-aryl phosphates 2 and 3 consisted in two nucleophilic substitution reactions with amines from cyanuric chloride, followed by a Suzuki coupling with the resulting 2,4-diamino-6-chloro-1,3,5-triazine derivative 12 to introduce the diaryl ether functionality. Aryl phosphate 4 was obtained via condensation of aryl guanidine 34 with aryloxyphenyl butenone 31. These de novo-designed aryl phosphates were evaluated as potential inhibitors of the Grb2-SH2 domain using an ELISA assay. The water-soluble sodium salt 26 of 3 gave an IC(50) value in the high micromolar range. Molecular modeling studies were subsequently performed upon modifying the 1,3,5-trisubstituted triazine scaffold of 3. Non-phosphate derivatives encompassing cyclopropane, pyrrole, keto-acid, and IZD fragments were thus step-wise designed and their Grb2-SH2 complexes were modeled by molecular dynamics. Some derivatives gave rise to an enriched pattern of H-bonds and cation-pi interactions with Grb2-SH2.

  9. Synthesis of Nano-sized Boehmites for Optimum Phosphate Sorption

    DEFF Research Database (Denmark)

    Watanabe, Yujiro; Kasama, Takeshi; Fukushi, Keisuke;

    2011-01-01

    Nano-sized boehmites with different crystallinity were synthesized at the temperature range of 25 to 200°C in order to produce phosphate absorbents with high capacity. The physicochemical property of boehmites was depended on the synthesis temperature: the particle size was increased and the surf......Nano-sized boehmites with different crystallinity were synthesized at the temperature range of 25 to 200°C in order to produce phosphate absorbents with high capacity. The physicochemical property of boehmites was depended on the synthesis temperature: the particle size was increased...... and the surface area showed the maximum for the boehmite at 50°C. The phosphate sorptions into boehmites were analyzed at room temperature in the phosphoric acid solutions as a model of wastewater at the concentration of 0.1 to 3.0 mmol l-1 and the pH of 3 to 7. The boehmite synthesized at 50°C exhibited...... the highest amount of phosphate sorption (1.73 mmol g-1 at pH 3.3) compared with Al-bearing materials. The reaction mechanism during phosphate sorption was described by the anion exchange reaction between phosphate ions in sodium phosphate solution and hydroxide ions on boehmite surfaces. Therefore...

  10. Pyridoxal phosphate-dependent neonatal epileptic encephalopathy.

    Science.gov (United States)

    Bagci, S; Zschocke, J; Hoffmann, G F; Bast, T; Klepper, J; Müller, A; Heep, A; Bartmann, P; Franz, A R

    2008-03-01

    Pyridox(am)ine-5'-phosphate oxidase converts pyridoxine phosphate and pyridoxamine phosphate to pyridoxal phosphate, a cofactor in many metabolic reactions, including neurotransmitter synthesis. A family with a mutation in the pyridox(am)ine-5'-phosphate oxidase gene presenting with neonatal seizures unresponsive to pyridoxine and anticonvulsant treatment but responsive to pyridoxal phosphate is described. Pyridoxal phosphate should be considered in neonatal epileptic encephalopathy unresponsive to pyridoxine.

  11. Pyridoxal phosphate-dependent neonatal epileptic encephalopathy

    OpenAIRE

    2009-01-01

    Pyridox(am)ine-5′-phosphate oxidase converts pyridoxine phosphate and pyridoxamine phosphate to pyridoxal phosphate, a cofactor in many metabolic reactions, including neurotransmitter synthesis. A family with a mutation in the pyridox(am)ine-5′-phosphate oxidase gene presenting with neonatal seizures unresponsive to pyridoxine and anticonvulsant treatment but responsive to pyridoxal phosphate is described. Pyridoxal phosphate should be considered in neonatal epileptic encephalopathy unrespons...

  12. INFLUENCE OF THE COMPOSITION OF PHOSPHATE ROCK ON THE AMOUNT OF WATER-INSOLUBLE PHOSPHATE IMPURITIES IN SEMI-HYDRATE PHOSPHOGYPSUM

    Directory of Open Access Journals (Sweden)

    Nora Kybartiene

    2015-03-01

    Full Text Available In this work a chemical and mineral composition of phosphate rock and phosphogypsum was investigated in order to identify which impurities of phosphate rock prevent natural phosphates from decomposing in full during the production of phosphoric acid and increase the amount of water-insoluble phosphate impurities in phosphogypsum. The analysis of X-ray diffraction (XRF, X-ray fluorescence (XRD, scanning electron microscopy with energy dispersive X-Ray spectrometry (SEM-EDS and granulometry was carried out. The results showed that phosphate rocks (Kovdor and Kirovsk apatites and the semi-hydrate phosphogypsums differ by their chemical composition. The apatites and phosphogypsums differ in the amount of the major components, as well as other components (MgO, Al2O3, SrO, BaO, ZrO2, Ln2O3. In phosphate rock, Ln2O3 can be found in the composition of the mineral monazite. The SEM-EDS analysis revealed that the minerals of the apatite group and monazite form aggregate crystals. Monazite dissolves in sulphuric and phosphoric acids very marginal, therefore it prevents the apatites from full decomposition, thus influencing the quantity of insoluble phosphates in semi-hydrate phosphogypsum. The higher is the amount of minerals containing Ln2O3 in phosphate rock, the more water-insoluble phosphates remain in phosphogypsum. It was found that influence of Ln2O3 impurity is significant higher than influence of particles size of apatite.

  13. Synthesis of Microcapsule by Staphylococcus aureus Is Not Responsive to Environmental Phosphate Concentrations

    OpenAIRE

    Fox, Karen F.; Stewart, George C.; Fox, Alvin

    1998-01-01

    The polysaccharide microcapsule of Staphylococcus aureus has been reported to be differentially expressed depending on growth conditions, with phosphate concentration being the critical environmental component. This study evaluated the effect of growth of a serotype 8 strain of S. aureus in phosphate-replete and phosphate-limiting media on microcapsule production. The presence of the cell wall polymers microcapsule and teichoic acid was measured by both gas chromatography-mass spectrometry an...

  14. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Aguilar, J.; Uriarte Hueda, A.

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

  15. Triphenyl phosphate allergy from spectacle frames

    DEFF Research Database (Denmark)

    Carlsen, L; Andersen, K E; Egsgaard, Helge

    1986-01-01

    A case of triphenyl phosphate allergy from spectacle frames is reported. Patch tests with analytical grade triphenyl phosphate, tri-m-cresyl phosphate, and tri-p-cresyl phosphate in the concentrations 5%, 0.5% and 0.05% pet. showed positive reactions to 0.05% triphenyl phosphate and 0.5% tri-m-cr...

  16. Origin of Life and the Phosphate Transfer Catalyst

    Science.gov (United States)

    Piast, Radosław W.; Wieczorek, Rafał M.

    2017-03-01

    In this paper, we revisit several issues relevant to origin-of-life research and propose a Phosphate Transfer Catalyst hypothesis that furthers our understanding of some of the key events in prebiotic chemical evolution. In the Phosphate Transfer Catalyst hypothesis, we assume the existence of hypothetical metallopeptides with phosphate transfer activity that use abundant polyphosphates as both substrates and energy sources. Nonspecific catalysis by this phosphate transfer catalyst would provide a variety of different products such as phosphoryl amino acids, nucleosides, polyphosphate nucleotides, nucleic acids, and aminoacylated nucleic acids. Moreover, being an autocatalytic set and metabolic driver at the same time, it could possibly replicate itself and produce a collective system of two polymerases; a nucleic acid able to catalyze peptide bond formation and a peptide able to polymerize nucleic acids. The genetic code starts at first as a system that reduces the energy barrier by bringing substrates (2'/3' aminoacyl-nucleotides) together, an ancestral form of the catalysis performed by modern ribosomes.

  17. Vibrio cholerae phosphatases required for the utilization of nucleotides and extracellular DNA as phosphate sources.

    Science.gov (United States)

    McDonough, EmilyKate; Kamp, Heather; Camilli, Andrew

    2016-02-01

    Phosphate is essential for life, being used in many core processes such as signal transduction and synthesis of nucleic acids. The waterborne agent of cholera, Vibrio cholerae, encounters phosphate limitation in both the aquatic environment and human intestinal tract. This bacterium can utilize extracellular DNA (eDNA) as a phosphate source, a phenotype dependent on secreted endo- and exonucleases. However, no transporter of nucleotides has been identified in V. cholerae, suggesting that in order for the organism to utilize the DNA as a phosphate source, it must first separate the phosphate and nucleoside groups before transporting phosphate into the cell. In this study, we investigated the factors required for assimilation of phosphate from eDNA. We identified PhoX, and the previously unknown proteins UshA and CpdB as the major phosphatases that allow phosphate acquisition from eDNA and nucleotides. We demonstrated separable but partially overlapping roles for the three phosphatases and showed that the activity of PhoX and CpdB is induced by phosphate limitation. Thus, this study provides mechanistic insight into how V. cholerae can acquire phosphate from extracellular DNA, which is likely to be an important phosphate source in the environment and during infection.

  18. Characterization of the mineral phosphate solubilizing activity of Serratia marcescens CTM 50650 isolated from the phosphate mine of Gafsa.

    Science.gov (United States)

    Ben Farhat, Mounira; Farhat, Ameny; Bejar, Wacim; Kammoun, Radhouan; Bouchaala, Kameleddine; Fourati, Amin; Antoun, Hani; Bejar, Samir; Chouayekh, Hichem

    2009-11-01

    The mineral phosphate solubilizing (MPS) ability of a Serratia marcescens strain, namely CTM 50650, isolated from the phosphate mine of Gafsa, was characterized on a chemically defined medium (NBRIP broth). Various insoluble inorganic phosphates, including rock phosphate (RP), calcium phosphate (CaHPO(4)), tri-calcium phosphate (Ca(3)(PO(4))(2)) and hydroxyapatite were tested as sole sources of phosphate for bacterial growth. Solubilization of these phosphates by S. marcescens CTM 50650 was very efficient. Indeed, under optimal conditions, the soluble phosphorus (P) concentration it produced reached 967, 500, 595 and 326 mg/l from CaHPO(4), Ca(3)(PO(4))(2), hydroxyapatite and RP, respectively. Study of the mechanisms involved in the MPS activity of CTM 50650, showed that phosphate solubilization was concomitant with significant drop in pH. HPLC-analysis of culture supernatants revealed the secretion of gluconic acid (GA) resulting from direct oxidation pathway of glucose when the CTM 50650 cells were grown on NBRIP containing glucose as unique carbon source. This was correlated with the simultaneous detection by PCR for the first time in a S. marcescens strain producing GA, of a gene encoding glucose dehydrogenase responsible for GA production, as well as the genes pqqA, B, C and E involved in biosynthesis of its PQQ cofactor. This study is expected to lead to the development of an environmental-friendly process for fertilizer production considering the capacity of S. marcescens CTM 50650 to achieve yields of P extraction up to 75% from the Gafsa RP.

  19. Phosphate-intercalated Ca-Fe-layered double hydroxides: Crystal structure, bonding character, and release kinetics of phosphate

    Science.gov (United States)

    Woo, Myong A.; Woo Kim, Tae; Paek, Mi-Jeong; Ha, Hyung-Wook; Choy, Jin-Ho; Hwang, Seong-Ju

    2011-01-01

    The nitrate-form of Ca-Fe-layered double hydroxide (Ca-Fe-LDH) was synthesized via co-precipitation method, and its phosphate-intercalates were prepared by ion-exchange reaction. According to X-ray diffraction analysis, the Ca-Fe-LDH-NO 3- compound and its H 2PO 4--intercalate showed hexagonal layered structures, whereas the ion-exchange reaction with HPO 42- caused a frustration of the layer ordering of LDH. Fe K-edge X-ray absorption spectroscopy clearly demonstrated that the Ca-Fe-LDH lattice with trivalent iron ions was well-maintained after the ion-exchange with HPO 42- and H 2PO 4-. Under acidic conditions, phosphate ions were slowly released from the Ca-Fe-LDH lattice and the simultaneous release of hydroxide caused the neutralization of acidic media. Fitting analysis based on kinetic models indicated a heterogeneous diffusion process of phosphates and a distinct dependence of release rate on the charge of phosphates. This study strongly suggested that Ca-Fe-LDH is applicable as bifunctional vector for slow release of phosphate fertilizer and for the neutralization of acid soil.

  20. Expanding sapphyrin: towards selective phosphate binding.

    Science.gov (United States)

    Katayev, Evgeny A; Boev, Nikolay V; Myshkovskaya, Ekaterina; Khrustalev, Victor N; Ustynyuk, Yu A

    2008-01-01

    The anion-templated syntheses and binding properties of novel macrocyclic oligopyrrole receptors in which pyrrole rings are linked through amide or imine bonds are described. The efficient synthesis was accomplished by anion-templated [1+1] Schiff-base condensation and acylation macrocyclization reactions. Free receptors and their host-guest complexes with hydrochloric acid, acetic acid, tetrabutylammonium chloride, and hydrogen sulfate were analyzed by single-crystal X-ray diffraction analysis. Stability constants with different tetrabutylammonium salts of inorganic acids were determined by standard 1H NMR and UV/Vis titration techniques in [D6]DMSO/0.5% water solution. According to the titration data, receptors containing three pyrrole rings (10 and 12) exhibit high affinity (log Ka=5-7) for bifluoride, acetate, and dihydrogen phosphate, and interact weakly with chloride and hydrogen sulfate. The amido-bipyrrole receptors 11 and 13 with four pyrrole rings exhibit 10(4)- and 10(2)-fold selectivity for dihydrogen phosphate, respectively, as inferred from competitive titrations in the presence of tetrabutylammonium acetate.

  1. Phosphate acquisition efficiency and phosphate starvation tolerance locus (PSTOL1) in rice

    Indian Academy of Sciences (India)

    Arijit Mukherjee; Sutanu Sarkar; Amrita Sankar Chakraborty; Roshan Yelne; Vinay Kavishetty; Tirthankar Biswas; N. Mandal; Somnath Bhattacharyya

    2014-12-01

    Phosphate availability is a major factor limiting tillering, grain filling vis-à-vis productivity of rice. Rice is often cultivated in soil like red and lateritic or acid, with low soluble phosphate content. To identify the best genotype suitable for these types of soils, P acquisition efficiency was estimated from 108 genotypes. Gobindabhog, Tulaipanji, Radhunipagal and Raghusail accumulated almost equal amounts of phosphate even when they were grown on P-sufficient soil. Here, we have reported the presence as well as the expression of a previously characterized rice gene, phosphate starvation tolerance locus (PSTOL1) in a set of selected genotypes. Two of four genotypes did not show any detectable expression but carried the gene. One mega cultivar, Swarna did not possess this gene but showed high P-deficiency tolerance ability. Increase of root biomass, not length, in P-limiting situations might be considered as one of the selecting criteria at the seedling stage. Neither the presence of PSTOL1 gene nor its closely-linked SSR RM1261, showed any association with P-deficiency tolerance among the 108 genotypes. Not only this, but the presence of PSTOL1 in recombinant inbred line (RIL) developed from a cross between Gobindabhog and Satabdi, also did not show any linkage with P-deficiency tolerance ability. Thus, before considering PSTOL1 gene in MAB, its expression and role in P-deficiency tolerance in the donor parent must be ascertained.

  2. Lipid phosphate phosphohydrolase-1 degrades exogenous glycerolipid and sphingolipid phosphate esters.

    Science.gov (United States)

    Jasinska, R; Zhang, Q X; Pilquil, C; Singh, I; Xu, J; Dewald, J; Dillon, D A; Berthiaume, L G; Carman, G M; Waggoner, D W; Brindley, D N

    1999-06-15

    Lipid phosphate phosphohydrolase (LPP)-1 cDNA was cloned from a rat liver cDNA library. It codes for a 32-kDa protein that shares 87 and 82% amino acid sequence identities with putative products of murine and human LPP-1 cDNAs, respectively. Membrane fractions of rat2 fibroblasts that stably expressed mouse or rat LPP-1 exhibited 3.1-3. 6-fold higher specific activities for phosphatidate dephosphorylation compared with vector controls. Increases in the dephosphorylation of lysophosphatidate, ceramide 1-phosphate, sphingosine 1-phosphate and diacylglycerol pyrophosphate were similar to those for phosphatidate. Rat2 fibroblasts expressing mouse LPP-1 cDNA showed 1.6-2.3-fold increases in the hydrolysis of exogenous lysophosphatidate, phosphatidate and ceramide 1-phosphate compared with vector control cells. Recombinant LPP-1 was located partially in plasma membranes with its C-terminus on the cytosolic surface. Lysophosphatidate dephosphorylation was inhibited by extracellular Ca2+ and this inhibition was diminished by extracellular Mg2+. Changing intracellular Ca2+ concentrations did not alter exogenous lysophosphatidate dephosphorylation significantly. Permeabilized fibroblasts showed relatively little latency for the dephosphorylation of exogenous lysophosphatidate. LPP-1 expression decreased the activation of mitogen-activated protein kinase and DNA synthesis by exogenous lysophosphatidate. The product of LPP-1 cDNA is concluded to act partly to degrade exogenous lysophosphatidate and thereby regulate its effects on cell signalling.

  3. Inositol phosphates induce DAPI fluorescence shift.

    Science.gov (United States)

    Kolozsvari, Bernadett; Parisi, Federica; Saiardi, Adolfo

    2014-06-15

    The polymer inorganic polyP (polyphosphate) and inositol phosphates, such as IP6 (inositol hexakisphosphate; also known as phytic acid), share many biophysical features. These similarities must be attributed to the phosphate groups present in these molecules. Given the ability of polyP to modify the excitation-emission spectra of DAPI we decided to investigate whether inositol phosphates possess the same property. We discovered that DAPI-IP6 complexes emit at approximately 550 nm when excited with light of wavelength 410-420 nm. IP5 (inositol pentakisphosphate) is also able to induce a similar shift in DAPI fluorescence. Conversely, IP3 (inositol trisphosphate) and IP4 (inositol tetrakisphosphate) are unable to shift DAPI fluorescence. We have employed this newly discovered feature of DAPI to study the enzymatic activity of the inositol polyphosphate multikinase and to monitor phytase phosphatase reactions. Finally, we used DAPI-IP6 fluorescence to determine the amount of IP6 in plant seeds. Using an IP6 standard curve this straight-forward analysis revealed that among the samples tested, borlotti beans possess the highest level of IP6 (9.4 mg/g of dry mass), whereas the Indian urad bean the lowest (3.2 mg/g of dry mass). The newly identified fluorescence properties of the DAPI-IP5 and DAPI-IP6 complexes allow the levels and enzymatic conversion of these two important messengers to be rapidly and reliably monitored.

  4. Frozen delivery of brushite calcium phosphate cements.

    Science.gov (United States)

    Grover, Liam M; Hofmann, Michael P; Gbureck, Uwe; Kumarasami, Balamurgan; Barralet, Jake E

    2008-11-01

    Calcium phosphate cements typically harden following the combination of a calcium phosphate powder component with an aqueous solution to form a matrix consisting of hydroxyapatite or brushite. The mixing process can be very important to the mechanical properties exhibited by cement materials and consequently when used clinically, since they are usually hand-mixed their mechanical properties are prone to operator-induced variability. It is possible to reduce this variability by pre-mixing the cement, e.g. by replacing the aqueous liquid component with non-reactive glycerol. Here, for the first time, we report the formation of three different pre-mixed brushite cement formulations formed by freezing the cement pastes following combination of the powder and liquid components. When frozen and stored at -80 degrees C or less, significant degradation in compression strength did not occur for the duration of the study (28 days). Interestingly, in the case of the brushite cement formed from the combination of beta-tricalcium phosphate with 2 M orthophosphoric acid solution, freezing the cement paste had the effect of increasing mean compressive strength fivefold (from 4 to 20 MPa). The increase in compression strength was accompanied by a reduction in the setting rate of the cement. As no differences in porosity or degree of reaction were observed, strength improvement was attributed to a modification of crystal morphology and a reduction in damage caused to the cement matrix during manipulation.

  5. Synthesis of coenzyme A thioesters using methyl acyl phosphates in an aqueous medium.

    Science.gov (United States)

    Pal, Mohan; Bearne, Stephen L

    2014-12-28

    Regioselective S-acylation of coenzyme A (CoA) is achieved under aqueous conditions using various aliphatic and aromatic carboxylic acids activated as their methyl acyl phosphate monoesters. Unlike many hydrophobic activating groups, the anionic methyl acyl phosphate mixed anhydride is more compatible with aqueous solvents, making it useful for conducting acylation reactions in an aqueous medium.

  6. The pentose phosphate pathway and cancer.

    Science.gov (United States)

    Patra, Krushna C; Hay, Nissim

    2014-08-01

    The pentose phosphate pathway (PPP), which branches from glycolysis at the first committed step of glucose metabolism, is required for the synthesis of ribonucleotides and is a major source of NADPH. NADPH is required for and consumed during fatty acid synthesis and the scavenging of reactive oxygen species (ROS). Therefore, the PPP plays a pivotal role in helping glycolytic cancer cells to meet their anabolic demands and combat oxidative stress. Recently, several neoplastic lesions were shown to have evolved to facilitate the flux of glucose into the PPP. This review summarizes the fundamental functions of the PPP, its regulation in cancer cells, and its importance in cancer cell metabolism and survival.

  7. Crystallo-chemical analyses of calcium phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Sakae, Toshiro; Hayakawa, Tohru; Maruyama, Fumiaki; Nemoto, Kimiya; Kozawa, Yukishige [Nihon Univ., Matsudo, Chiba (Japan). School of Dentistry

    1997-12-01

    Several analytical techniques, methodology and their practical data processing were briefly described to investigate the crystallographic properties of calcium phosphates which are encountered in the field of dental sciences. The applied analytical techniques were X-ray fluorescence spectrometry (XFS), energy dispersive spectrometry (EDS), Fourier transform infrared spectrometry (FT-IR) and X-ray diffraction (XRD). The used materials were tetracalcium phosphate, hydroxyapatite, fluorapatite, {alpha}-tricalcium phosphate, {beta}-tricalcium phosphate, octacalcium phosphate, monetite, brushite and monocalcium phosphate monohydrate. (author)

  8. Kinetic and Equilibrium Constants of Phytic Acid, Ferric and Ferrous Phytate Derived From Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Inositol phosphates are metabolically derived organic phosphates that increasingly appear to be an important sink and source of phosphate in the environment. Inositol hexakis dihydrogen phosphate or phytic acid is the most common inositol phosphate in the environment. Iron is abundant in many terr...

  9. A Selective and Mild Synthetic Route to Dialkyl Phosphates

    NARCIS (Netherlands)

    Kuiper, Johanna M.; Hulst, Ron; Engberts, Jan B.F.N.

    2003-01-01

    A very mild synthetic route to dialkyl phosphates is described. Reaction of the appropriate alcohol with PCl3 followed by treatment with pyridine and CCl4 afforded the corresponding trichloromethyl ester. Subsequent reaction with the triethylamine salt of acetic acid followed by hydrolysis of the fo

  10. Adsorption of Phosphate on Goethite: An Undergraduate Research Laboratory Project

    Science.gov (United States)

    Tribe, Lorena; Barja, Beatriz C.

    2004-01-01

    A laboratory experiment on the adsorption of phosphate on goethite is presented, which also includes discussion on surface properties, interfaces, acid-base equilibrium, molecular structure and solid state chemistry. It was seen that many students were able to produce qualitatively correct results for a complex system of real interest and they…

  11. Study on Extraction Performance of Tri-iso-amyl Phosphate

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The distribution performance of HNO3, Pu(Ⅲ ), Pu(Ⅳ) and Np(Ⅳ) in the two phase system of Tri-iso-Amyl Phosphate(TiAP) and aqueous, the influence of the concentration of extractant, nitric acid and Al(NO3)3 on the distribution ratio of Pu(Ⅲ ),

  12. Phosphite disrupts the acclimation of Saccharomyces cerevisiae to phosphate starvation.

    Science.gov (United States)

    McDonald, A E; Niere, J O; Plaxton, W C

    2001-11-01

    The influence of phosphite (H2PO3-) on the response of Saccharomyces cerevisiae to orthophosphate (HPO4(2-); Pi) starvation was assessed. Phosphate-repressible acid phosphatase (rAPase) derepression and cell development were abolished when phosphate-sufficient (+Pi) yeast were subcultured into phosphate-deficient (-Pi) media containing 0.1 mM phosphite. By contrast, treatment with 0.1 mM phosphite exerted no influence on rAPase activity or growth of +Pi cells. 31P NMR spectroscopy revealed that phosphite is assimilated and concentrated by yeast cultured with 0.1 mM phosphite, and that the levels of sugar phosphates, pyrophosphate, and particularly polyphosphate were significantly reduced in the phosphite-treated -Pi cells. Examination of phosphite's effects on two PHO regulon mutants that constitutively express rAPase indicated that (i) a potential target for phosphite's action in -Pi yeast is Pho84 (plasmalemma high-affinity Pi transporter and component of a putative phosphate sensor-complex), and that (ii) an additional mechanism exists to control rAPase expression that is independent of Pho85 (cyclin-dependent protein kinase). Marked accumulation of polyphosphate in the delta pho85 mutant suggested that Pho85 contributes to the control of polyphosphate metabolism. Results are consistent with the hypothesis that phosphite obstructs the signaling pathway by which S. cerevisiae perceives and responds to phosphate deprivation at the molecular level.

  13. The effect of phosphate additives on the lubrication of rolling element bearings in a refrigerant environment

    Energy Technology Data Exchange (ETDEWEB)

    Tuomas, Roger; Isaksson, Ove [Luleaa University of Technology, Division of Machine Elements, SE-971 87 Luleaa (Sweden)

    2007-01-15

    Chlorine free replacement refrigerants, HFC (hydrofluorocarbons) and HC (hydrocarbons), have shown less lubricating properties. Phosphate based additives were used to improve the lubricity with refrigerant R-134a, demonstrating positive effects. In the present paper, the ability to form lubricating film and wear of two additives, phosphate ester and acid phosphate, was investigated in a bearing test apparatus. The results show that phosphate additive in polyolester oil, in an R-134a environment, increases the lubricating film and reduce wear. Surface topography during the initial run-in changes to a more favorable profile with lower RMS angle and longer wavelengths that promote load-carrying capacity and film build-up. (author)

  14. The radiological impact of the Belgian phosphate industry

    Energy Technology Data Exchange (ETDEWEB)

    Vanmarcke, H.; Paridaens, J. [Belgian Nuclear Research Centre, SCK.CEN, Boeretang 200, 2400 Mol (Belgium)

    2006-07-01

    The Belgian phosphate industry processes huge amounts of phosphate ore (1.5 to 2 Mton/year) for a wide range of applications, the most important being the production of phosphoric acid, fertilizers and cattle food. Marine phosphate ores show high specific activities of the natural uranium decay series (usually indicated by Ra-226) (e.g. 1200 to 1500 Bq/kg for Moroccan ore). Ores of magmatic origin generally contain less of the uranium and more of the thorium decay series (up to 500 Bq/kg). These radionuclides turn up in by-products, residues or product streams depending on the processing method and the acid used for the acidulation of the phosphate rock. Sulfuric acid is the most widely used, but also hydrochloric acid and nitric acid are applied in Belgium. For Flanders, the northern part of Belgium, we already have a clear idea of the production processes and waste streams. The five Flemish phosphate plants, from 1920 to 2000, handled 54 million ton of phosphate ore containing 65 TBq of radium-226 and 2.7 TBq of thorium- 232. The total surface area of the phosphogypsum and calcium fluoride sludge deposits amounts to almost 300 ha. There is also environmental contamination along two small rivers receiving the waste waters of the hydrochloric production process: the Winterbeek (> 200 ha) and the Grote Laak (12 ha). The data on the impact of the phosphate industry in the Walloon provinces in Belgium is less complete. A large plant produced in 2004 0.8 Mton of phosphogypsum, valorizing about 70 % of the gypsum in building materials (plaster, cement), in fertilizers, and in other products such as paper. The remainder was stored on a local disposal site. The radiological impact of the Belgian phosphate industry on the local population will be discussed. At present most contaminated areas are still recognizable as waste deposits and inaccessible to the population. However as gypsum deposits and other contaminated areas quickly blend in with the landscape, it is

  15. The role of brushite and octacalcium phosphate in apatite formation.

    Science.gov (United States)

    Johnsson, M S; Nancollas, G H

    1992-01-01

    Studies of apatite mineral formation are complicated by the possibility of forming several calcium phosphate phases. The least soluble, hydroxyapatite (HAP), is preferentially formed under neutral or basic conditions. In more acidic solutions phases such as dicalcium phosphate dihydrate (Brushite, DCPD) and octacalcium phosphate (OCP) are often found. Even under ideal HAP precipitation conditions the precipitates are generally nonstoichiometric, suggesting the formation of calcium-deficient apatites. Both DCPD and OCP have been implicated as possible precursors to the formation of apatite. This may occur by the initial precipitation of DCPD and/or OCP followed by transformation to a more apatitic phase. Although DCPD and OCP are often detected during in vitro crystallization, in vivo studies of bone formation rarely show the presence of these acidic calcium phosphate phases. In the latter case the situation is more complicated, since a large number of ions and molecules are present that can be incorporated into the crystal lattice or adsorbed at the crystallite surfaces. In biological apatite, DCPD and OCP are usually detected only during pathological calcification where the pH is often relatively low. In normal in vivo calcifications these phases have not been found, suggesting the involvement of other precursors or the formation of an initial amorphous calcium phosphate phase (ACP) followed by transformation to apatite.

  16. Homogeneous Iron Phosphate Nanoparticles by Combustion of Sprays.

    Science.gov (United States)

    Rudin, Thomas; Pratsinis, Sotiris E

    2012-06-13

    Low-cost synthesis of iron phosphate nanostructured particles is attractive for large scale fortification of basic foods (rice, bread, etc.) as well as for Li-battery materials. This is achieved here by flame-assisted and flame spray pyrolysis (FASP and FSP) of inexpensive precursors (iron nitrate, phosphate), solvents (ethanol), and support gases (acetylene and methane). The iron phosphate powders produced here were mostly amorphous and exhibited excellent solubility in dilute acid, an indicator of relative iron bioavailability. The amorphous and crystalline fractions of such powders were determined by X-ray diffraction (XRD) and their cumulative size distribution by X-ray disk centrifuge. Fine and coarse size fractions were obtained also by sedimentation and characterized by microscopy and XRD. The coarse size fraction contained maghemite Fe(2)O(3) while the fine was amorphous iron phosphate. Furthermore, the effect of increased production rate (up to 11 g/h) on product morphology and solubility was explored. Using increased methane flow rates through the ignition/pilot flame of the FSP-burner and inexpensive powder precursors resulted in also homogeneous iron phosphate nanoparticles essentially converting the FSP to a FASP process. The powders produced by FSP at increased methane flow had excellent solubility in dilute acid as well. Such use of methane or even natural gas might be economically attractive for large scale flame-synthesis of nanoparticles.

  17. Phosphate Solubilization Potentials of Rhizosphere Isolates from Central Anatolia (Turkey)

    Science.gov (United States)

    Ogut, M.; Er, F.

    2009-04-01

    Plant available-phosphorus (P) is usually low in Anatolian soils due mainly to the precipitation as calcium (Ca) and magnesium (Mg) phosphates in alkaline conditions. Phosphate solubilizing microorganisms (PSM) can enhance plant P-availability by dissolving the hardly soluble-P within the rhizosphere, which is the zone that surrounds the plant roots. PSM's can be used as seed- or soil-inocula to increase plant P-uptake and the overall growth. A total of 162 PSM's were isolated from the rhizosphere of wheat plants excavated from different fields located along a 75 km part of a highway in Turkey. The mean, the standart deviation, and the median for solubilized-P (ppm) in a 24 h culture in a tricalcium phosphate broth were 681, 427, and 400 for glucose; 358, 266, and 236 for sucrose; and 102, 117, and 50 for starch, respectively. There was not a linear relationship between the phosphate solubilized in the liquid cultures and the solubilization index obtained in the Pikovskaya's agar. Nine isolates representing both weak and strong solubilizers [Bacillus megaterium (5), Bacillus pumilis (1), Pseudomonas syringae pv. phaseolica (1), Pseudomonas fluorescens (1), Arthrobacter aurescens (1) as determined by the 16S rRNA gene sequence analysis] were further studied in a five day incubation. Pseudomonas syringae pv. phaseolica solubilized statistically (P<0.05) higher phosphate (409 ppm) than all the other strains did. There was not a statistically significant (P<0.05) difference in solubilized-P among the Bacillus strains. The pH of the medium fell to the levels between 4 and 5 from the initial neutrality. The phosphate solubilizing strains variably produced gluconic, 2-keto-D-gluconic, glycolic, acetic and butyric acids. The organic acids produced by these microorganisms seem to be the major source of phosphate solubilization in vitro.

  18. Oxygen isotopes of phosphatic compounds - Application for marine particulate matter, sediments and soils

    Science.gov (United States)

    McLaughlin, K.; Paytan, A.; Kendall, C.; Silva, S.

    2006-01-01

    The phosphate oxygen isotopic composition in naturally occurring particulate phosphatic compounds (??18Op) can be used as a tracer for phosphate sources and to evaluate the cycling of phosphorus (P) in the environment. However, phosphatic compounds must be converted to silver phosphate prior to isotopic analysis, a process that involves digestion of particulate matter in acid. This digestion will hydrolyze some of the phosphatic compounds such that oxygen from the acid solution will be incorporated into the sample as these phosphatic compounds are converted to orthophosphate (PO 43-). To determine the extent of incorporation of reagent oxygen into the sample, we digested various phosphatic compounds in both acid amended with H218O (spiked) and unspiked acid and then converted the samples to silver phosphate for ??18Op analysis. Our results indicate that there is no isotopic fractionation associated with acid digestion at 50??C. Furthermore, we found that reagent oxygen incorporation is a function of the oxygen to phosphorus ratio (O:P) of the digested compound whereby the percentage of reagent oxygen incorporated into the sample is the same as that which is required to convert all of the P-compounds into orthophosphate. Based on these results, we developed a correction for reagent oxygen incorporation using simple mass balance, a procedure that allows for the determination of the ??18O p of samples containing a mixture of phosphatic compounds. We analyzed a variety of environmental samples for ??18O p to demonstrate the utility of this approach for understanding sources and cycling of P. ?? 2005 Elsevier B.V. All rights reserved.

  19. Characterization of a calcium phosphate cement based on alpha-tricalcium phosphate obtained by wet precipitation process

    Energy Technology Data Exchange (ETDEWEB)

    Thurmer, M.B.; Diehl, C.E.; Vieira, R.S.; Coelho, W.T.G.; Santos, L.A., E-mail: monicathurmer@yahoo.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Engenharia de Materiais

    2012-07-01

    There are several systems of calcium phosphate cements being studied. Those based on alpha-tricalcium phosphate are of particular interest. After setting they produce calcium deficient hydroxyapatite similar to bone like hydroxyapatite. This work aims to obtain alpha-tricalcium phosphate powders by the wet precipitation process, using calcium nitrate and phosphoric acid as reagents. This powder was characterized by infrared spectroscopy, X-ray diffraction and particle size distribution. In order to prepare the calcium phosphate cement, the powder was mixed with an accelerator in an aqueous solution. The mechanical properties of the cement were assessed and it was evaluated by means of apparent density, X-ray diffraction and scanning electron microscopy. The described method produced crystalline alpha-tricalcium phosphate as the major phase. The calcium phosphate cement showed high values of compression strength (50 MPa). The soaking of the cement in a simulated body fluid (SBF) formed a layer of hydroxyapatite like crystals in the surface of the samples. (author)

  20. Phosphate solubilizing bacteria and alkaline phosphatase activity in coastal waters off Trivandrum

    Digital Repository Service at National Institute of Oceanography (India)

    Mamatha, S.S.; Gobika, A.; Janani, P.

    Phosphorus is a key nutrient in marine environment. Phosphate solubilising bacteria (PSB) have the ability to solubilise ionic forms of orthophosphoric acid to free form of phosphrous in the water column. Both PSB and alkaline phosphatase activity...

  1. Topotactic exchange and intercalation of calcium phosphate

    Science.gov (United States)

    Lima, Cicero B. A.; Airoldi, Claudio

    2004-11-01

    The precursor (NH 4) 2Ca(H 2PO 4) 2ṡH 2O (CaAP) compound was obtained by combining a calcium chloride solution with dibasic ammonium phosphate. After submitting it to a thermal treatment, crystalline calcium phosphate, Ca(H 2PO 4) 2ṡH 2O (CaP) was isolated. X-ray diffraction patterns for this compound indicated good crystallinity, with a peak at 2θ=12.8°, to give an interlamellar distance of 697 pm, which changed to 1550 pm, when the reaction employed phenylphosphonic acid, and to 1514 pm when intercalated with methylamine. Phosphorus and calcium analysis from colorimetric and gravimetric methods gave for CaP 24.2 and 15.8%, respectively, to yield a P:Ca molar ratio equal to two. The phosphorus nuclear magnetic resonance presented a peak centered at -1.23 ppm, in agreement with the existence of phosphate groups in protonated form. CaAP showed a mass loss of 21.2% in the 466 to 541 K interval due to ammonia and water elimination to yield Ca(PO 3) 3, and CaP can be dehydrated at 440 K for 6 h. A topotactical exchange occurred when CaP is intercalated with methylamine or reacted with phenylphosphonic acid to yield the phosphonate compound and the infrared spectrum of the resulting compound clearly showed the presence of PO 4 and PO 3 groups. The topotactic exchange was also demonstrated by X-ray diffractometry in following the stages of decomposition from 527 to 973 K.

  2. Triphenyl phosphate allergy from spectacle frames

    DEFF Research Database (Denmark)

    Carlsen, Lars; Andersen, Klaus E.; Egsgaard, Helge

    1986-01-01

    A case of triphenyl phosphate allergy from spectacle frames is reported. Patch tests with analytical grade triphenyl phosphate, tri-m-cresyl phosphate, and tri-p-cresyl phosphate in the concentrations 5%, 0.5% and 0.05% pet. showed positive reactions to 0.05% triphenyl phosphate and 0.5% tri......-m-cresyl phosphate, but no reaction to tri-p-cresyl phosphate. Gas chromatography of the tricresyl phosphate 5% pet. patch test material supplied from Trolab showed that it contained a mixture of a wide range of triaryl phosphates, including 0.08% triphenyl phosphate which is above the threshold for detecting...... triphenyl phosphate allergy in our patient....

  3. High inorganic phosphate causes DNMT1 phosphorylation and subsequent fibrotic fibroblast activation

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xiaoying [Department of Nephrology and Rheumatology, Göttingen University Medical Center, Georg August University, Göttingen (Germany); Department of Cardiology and Pneumology, Göttingen University Medical Center, Georg August University, Göttingen (Germany); Xu, Xingbo [Department of Cardiology and Pneumology, Göttingen University Medical Center, Georg August University, Göttingen (Germany); Zeisberg, Elisabeth M. [Department of Cardiology and Pneumology, Göttingen University Medical Center, Georg August University, Göttingen (Germany); German Center for Cardiovascular Research (DZHK), Göttingen (Germany); Zeisberg, Michael, E-mail: mzeisberg@med.uni-goettingen.de [Department of Nephrology and Rheumatology, Göttingen University Medical Center, Georg August University, Göttingen (Germany); German Center for Cardiovascular Research (DZHK), Göttingen (Germany)

    2016-04-08

    Phosphate is an essential constituent of critical cellular functions including energy metabolism, nucleic acid synthesis and phosphorylation-dependent cell signaling. Increased plasma phosphate levels are an independent risk factor for lowered life-expectancy as well as for heart and kidney failure. Nevertheless, direct cellular effects of elevated phosphate concentrations within the microenvironment are poorly understood and have been largely neglected in favor of phosphor-regulatory hormones. Because interstitial fibrosis is the common determinant of chronic progressive kidney disease, and because fibroblasts are major mediators of fibrogenesis, we here explored the effect of high extracellular phosphate levels on renal fibroblasts. We demonstrate that high inorganic phosphate directly induces fibrotic fibroblast activation associated with increased proliferative activity, increased expression of α-smooth muscle actin and increased synthesis of type I collagen. We further demonstrate that such fibroblast activation is dependent on phosphate influx, aberrant phosphorylation of DNA methyltransferase DNMT1 and aberrant CpG island promoter methylation. In summary, our studies demonstrate that elevated phosphate concentrations induce pro-fibrotic fibroblast activation independent of phospho-regulatory hormones. - Highlights: • We exposed human kidney fibroblasts to media containing 1 mM or 3 mM phosphate. • Increased phosphate influx causes phosphorylation of DNA methyltransferase Dnmt1. • Phosphorylated Dnmt1 causes promoter methylation and transcriptional silencing of RASAL1. • Depletion of RASAL1 causes increased intrinsic Ras-GTP activity and fibroblast activation. • Inorganic phosphate causes fibroblast activation independent of phospho-regulatory hormones.

  4. Removal of Phosphate Using Red Mud: An Environmentally Hazardous Waste By-Product of Alumina Industry

    Directory of Open Access Journals (Sweden)

    Shivkumar S. Prajapati

    2016-01-01

    Full Text Available The industrial waste, bauxite residue generated in the Bayer chemical process of alumina production, commonly known as red mud (RM has been used as the adsorbent for selective removal of phosphate in aqueous solutions. RM collected from the storage area of alumina industry was characterized by chemical analysis and physical methods such as BET surface area, Scanning Electron Microscopy (SEM, particle size analysis, and X-ray diffraction (XRD methods. Among the various red mud samples (0.2–200 μ studied, the samples treated with 1 M HCl for 2 h were found better for the selective adsorption of phosphate in comparison with untreated and heat treated RM samples. The presence of phosphate in the aqueous samples collected after adsorption studies with red mud was determined by standard spectrophotometric procedure using ammonium molybdate and ascorbic acid in nitrate medium at λmax 880 nm. The studies reported significant adsorption of phosphate on acid treated red mud in comparison with adsorption of phosphate on untreated and heat treated red mud, respectively. The adsorption of phosphate on raw red mud and activated red mud was further investigated with respect to stirring time, pH of the solution, dose of adsorbent, and varying phosphate concentration. Acid treated RM is observed as an efficient and cost-effective adsorbent for selective removal of phosphate in aqueous solutions.

  5. Effect of Phosphate on U(VI) Sorption to Montmorillonite: Ternary Complexation and Precipitation Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming; Wang, Zimeng; Mehta, Vrajesh; Giammar, Daniel; Catalano, Jeffrey G.

    2016-02-15

    Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated. Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This work

  6. Effect of phosphate on U(VI) sorption to montmorillonite: Ternary complexation and precipitation barriers

    Science.gov (United States)

    Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming; Wang, Zimeng; Mehta, Vrajesh S.; Giammar, Daniel E.; Catalano, Jeffrey G.

    2016-02-01

    Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated. Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This work

  7. Inducing Mineral Precipitation in Groundwater by Addition of Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Karen E. Wright; Yoshiko Fujita; Thomas Hartmann; Mark Conrad

    2011-10-01

    Induced precipitation of phosphate minerals to scavenge trace metals and radionuclides from groundwater is a potential remediation approach for contaminated aquifers. Phosphate minerals can sequester trace elements by primary mineral formation, solid solution formation and/or adsorption, and they are poorly soluble under many environmental conditions, making them attractive for long-term sustainable remediation. The success of such engineered schemes will depend on the particular mineral phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for induced phosphate mineral precipitation rely on the stimulation of native groundwater populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 ml-1) within the precipitation medium. We also tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM). The experiments showed that the general progression of mineral precipitation was similar under all of the conditions, with initial formation of amorphous calcium carbonate, and transformation to poorly crystalline hydroxyapatite (HAP) by the end of the week-long experiments. The presence of the bacterial cells appeared to delay precipitation, although by the end of 7 days the overall extent of precipitation was similar for all of the treatments. The stoichiometry of the final precipitates as well as results of Rietveld refinement of x-ray diffraction data indicated that the treatments including organic acids and bacterial cells resulted in increased distortion of the HAP crystal lattice, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the phosphate minerals was decreased in the treatments

  8. Evaluation for rock phosphate solubilization in fermentation and soil-plant system using a stress-tolerant phosphate-solubilizing Aspergillus niger WHAK1.

    Science.gov (United States)

    Xiao, Chunqiao; Zhang, Huaxiang; Fang, Yujuan; Chi, Ruan

    2013-01-01

    A strain WHAK1, identified as Aspergillus niger, was isolated from Yichang phosphate mines in Hubei province of China. The fungus developed a phosphate solubilization zone on modified National Botanical Research Institute's phosphate growth (NBRIP) agar medium, supplemented with tricalcium phosphate. The fungus was applied in a repeated-batch fermentation process in order to test its effect on solubilization of rock phosphate (RP). The results showed that A. niger WHAK1 could effectively solubilize RP in NBRIP liquid medium and released soluble phosphate in the broth, which can be illustrated by the observation of scanning electron microscope, energy-dispersive X-ray microanalysis, and Fourier transform infrared spectroscopy. Acidification of the broth seemed to be the major mechanism for RP solubilization by the fungus. Indeed, multiple organic acids (mainly gluconic acid) were detected in the broth by high-performance liquid chromatography analysis. These organic acids caused a significant drop of pH and an obvious rise of titratable acidity in the broth. The fungus also exhibited high levels of tolerance against temperature, pH, salinity, and desiccation stresses, although a significant decline in the fungal growth and release of soluble phosphate was marked under increasing intensity of stress parameters. Further, the fungus was introduced into the soil supplemented with RP to analyze its effect on plant growth and phosphate uptake of wheat plants. The result revealed that inoculation of A. niger WHAK1 significantly increased the growth and phosphate uptake of wheat plants in the RP-amended soil compared to the control soil.

  9. Method and apparatus for ion sequestration and a nanostructured metal phosphate

    Science.gov (United States)

    Mattigod, Shas V.; Fryxell, Glen E.; Li, Xiaohong; Parker, Kent E.; Wellman, Dawn M.

    2010-04-06

    A nanostructured substance, a process for sequestration of ionic waste, and an ion-sequestration apparatus are disclosed in the specification. The nanostructured substance can comprise a Lewis acid transition metal bound to a phosphate, wherein the phosphate comprises a primary structural component of the substance and the Lewis acid transition metal is a reducing agent. The nanostructured substance has a Brunner-Emmet-Teller (BET) surface area greater than or equal to approximately 100 m.sup.2/g, and a distribution coefficient for an analyte, K.sub.d, greater than or equal to approximately 5000 ml/g. The process can comprise contacting a fluid and a nanostructured metal phosphate. The apparatus can comprise a vessel and a nanostructured metal phosphate. The vessel defines a volume wherein a fluid contacts the nanostructured metal phosphate.

  10. Metal Phosphates as Proton Conducting Materials for Intermediate Temperature Fuel Cell and Electrolyser Applications

    DEFF Research Database (Denmark)

    Anfimova, Tatiana

    The present thesis presents the results achieved during my ph.d. project on a subject of intermediate temperature proton conducting metal phosphates as electrolyte materials for fuel cells and electrolysers. Fuel cells and electrolysers are electrochemical devices with high energy conversion...... with a proton conductivity of above 10-2S cm-1. Chapter 1 of the thesis is an introduction to basics of fuel cell and electrolyser technologies as well as proton conducting materials. Extended discussion on the proton conducting materials, a particularly phosphates is made in Chapter 2. Three major types...... of phosphates were systematically reviewed including solid acids or alkali hydrogen phosphates, pyrophosphates, and rare earth metal phosphates. Demonstration of the fuel cell technology based on solid acid proton conductor CsH2PO4 has inspired the active research in the area. Based on the literature survey...

  11. Distribution of natural radionuclides in the production and use of phosphate fertilizers in Brazil.

    Science.gov (United States)

    Saueia, C H R; Mazzilli, B P

    2006-01-01

    The Brazilian phosphate fertilizer is obtained by wet reaction of igneous phosphate rock with concentrated sulphuric acid, giving as final product, phosphoric acid and dehydrated calcium sulphate (phosphogypsum) as by-products. Phosphoric acid is the starting material for triple superphosphate (TSP), single superphosphate (SSP), monoammonium phosphate (MAP) and diammonium phosphate (DAP). The phosphate rock used as raw material presents in its composition radionuclides of the U and Th natural series. Taking this into account, the main aim of this paper is to evaluate the fluxes of natural radionuclides and radioactive disequilibria involved in the Brazilian industrial process of phosphoric acid production; to determine the content of radioactivity in several commercial fertilizers produced by this industry; to estimate their radiological impact in crop soils and the long term exposure due to their application. Radiological characterization of phosphate rock, phosphogypsum and phosphate fertilizers was performed by alpha and gamma spectrometry. The fertilizer samples, which are derived directly from phosphoric acid, MAP and DAP, presented in their composition low activity concentrations for 226Ra, 228Ra and 210Pb. As for U and Th, the concentrations found in MAP and DAP are more significant, up to 822 and 850Bqkg(-1), respectively. SSP and TSP, which are obtained by mixing phosphoric acid with different amounts of phosphate rock, presented higher concentrations of radionuclides, up to 1158Bqkg(-1) for (238)U, 1167Bqkg(-1) for (234)U, 1169Bqkg(-1) for 230Th, 879Bqkg(-1) for 226Ra, 1255Bqkg(-1) for 210Pb, 521Bqkg(-1) for 232Th, 246Bqkg(-1) for 228Ra and 302Bqkg(-1) for 228Th. Long term exposure due to successive fertilizer applications was evaluated. Internal doses due to the application of phosphate fertilizer for 10, 50 and 100 years were below 1mSvy(-1), showing that the radiological impact of such practice is negligible.

  12. Synthesis of 4-substituted tetrahydropyridines by cross-coupling of enol phosphates

    DEFF Research Database (Denmark)

    Larsen, U.S.; Martiny, L.; Begtrup, M.

    2005-01-01

    Enol phosphates, synthesized from 4-piperidone, react by palladium catalyzed cross-coupling with arylboronic acids and by iron and palladium catalyzed cross-coupling with Grignard reagents to give 4-substituted tetrahydropyridines. (c) 2005 Elsevier Ltd. All rights reserved.......Enol phosphates, synthesized from 4-piperidone, react by palladium catalyzed cross-coupling with arylboronic acids and by iron and palladium catalyzed cross-coupling with Grignard reagents to give 4-substituted tetrahydropyridines. (c) 2005 Elsevier Ltd. All rights reserved....

  13. Phosphate Modulates Transcription of Soybean VspB and Other Sugar-Inducible Genes.

    Science.gov (United States)

    Sadka, A.; DeWald, D. B.; May, G. D.; Park, W. D.; Mullet, J. E.

    1994-05-01

    The soybean vegetative storage protein genes VspA and VspB encode vacuolar glycoprotein acid phosphatases. Transcription of the Vsp is synergistically activated by jasmonic acid or methyl jasmonate (MeJA) and soluble sugars. The action of these modulators is mediated by two different DNA domains in the VspB promoter. In this study, we present new data regarding VspB regulation by sucrose and inorganic phosphate, which suggest a common mechanism of transcriptional control for Vsp and other sugar-inducible genes. We found that the sugar-mediated activation of VspB expression was inhibited by phosphate. Deletion analysis and transient assays in tobacco protoplasts identified a 130-bp DNA domain in the VspB promoter that mediates both sucrose induction and phosphate inhibition. Transcription mediated by this DNA domain was induced by phosphate elimination from the protoplast incubation medium, even in the absence of sucrose. The effect of sucrose and phosphate on VspB expression was studied in vivo in several ways. Depletion of phosphate from soybean cell cultures by the addition of mannose stimulated VspB expression, even in the absence of sucrose or MeJA. In illuminated soybean leaves treated with MeJA, inhibition of photosynthetic electron transport by DCMU decreased VspB expression. In contrast, VspB expression in soybean leaves stimulated by phosphate depletion was not influenced by DCMU. Moreover, sucrose-stimulated expression of the sugar-responsive genes lipoxygenase A and chalcone synthase of soybean and proteinase inhibitor II and class I patatin of potato was inhibited by phosphate. Like VspB, these genes were stimulated by phosphate depletion in the absence of exogenous sucrose. We propose that sugar-responsive genes are activated, in part, by accumulation of sugar-phosphates and concomitant reduction of cellular phosphate levels. These data may help explain recruitment of the Vsp, which encode acid phosphatases, as vegetative storage proteins.

  14. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.

    2017-07-01

    The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

  15. Variability of nitrate and phosphate

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Sundar, D.

    Nitrate and phosphate are important elements of the biogeochemical system of an estuary. Observations carried out during the dry season April-May 2002, and March 2003 and wet season September 2002, show temporal and spatial variability of these two...

  16. Recent advances in phosphate biosensors.

    Science.gov (United States)

    Upadhyay, Lata Sheo Bachan; Verma, Nishant

    2015-07-01

    A number of biosensors have been developed for phosphate analysis particularly, concerning its negative impact within the environmental and biological systems. Enzymatic biosensors comprising either a single or multiple enzymatic system have been extensively used for the direct and indirect analysis of phosphate ions. Furthermore, some non-enzymatic biosensors, such as affinity-based biosensors, provide an alternative analytical approach with a higher selectivity. This article reviews the recent advances in the field of biosensor developed for phosphate estimation in clinical and environmental samples, concerning the techniques involved, and the sensitivity toward phosphate ions. The biosensors have been classified and discussed on the basis of the number of enzymes used to develop the analytical system, and a comparative analysis has been performed.

  17. Synthesis and characterization of uranium (IV) phosphate-hydrogenphosphate hydrate and cerium (IV) phosphate-hydrogenphosphate hydrate

    Science.gov (United States)

    Brandel, V.; Clavier, N.; Dacheux, N.

    2005-04-01

    A new uranium (IV) phosphate of proposed formula U 2(PO 4) 2HPO 4·H 2O, i.e. uranium phosphate-hydrogenphosphate hydrate (UPHPH), was synthesized in autoclave and/or in polytetrafluoroethylene closed containers at 150 °C by three ways: from uranium (IV) hydrochloric solution and phosphoric acid, from uranium dioxide and phosphoric acid and by transformation of the uranium hydrogenphosphate hydrate U(HPO 4) 2· nH 2O. The new product appears similar to the previously published thorium phosphate-hydrogenphosphate hydrate Th 2(PO 4) 2HPO 4·H 2O (TPHPH). From preliminary studies, it was found that UPHPH crystallizes in monoclinic system ( a=2.1148(7) nm, b=0.6611(2) nm, c=0.6990(3) nm, β=91.67(3)° and V=0.9768(10) nm). Heated under inert atmosphere, this compound is decomposed above 400 °C into uranium phosphate-triphosphate U 2(PO 4)P 3O 10, uranium diphosphate α-UP 2O 7 and diuranium oxide phosphate U 2O(PO 4) 2. Crystallized cerium (IV) phosphate-hydrogenphosphate hydrate Ce 2(PO 4) 2HPO 4·H 2O (CePHPH) was also synthesized from (NH 4) 2Ce(NO 3) 6 and phosphoric acid solutions by the same method (monoclinic system: a=2.1045(5) nm, b=0.6561(2) nm, c=0.6949(2) nm, β=91.98(1)° and V=0.9588(9) nm). When heating above 600 °C, cerium (IV) is reduced into Ce (III) and forms a mixture of CePO 4 (monazite structure) and CeP 3O 9.

  18. Ionothermal Synthesis and Characterization of Crystalline Zirconium Phosphate from Oxalic Acid/Tetrapropyl Ammonium Bromide System%草酸/四丙基溴化铵体系中磷酸锆晶体的离子热合成与表征

    Institute of Scientific and Technical Information of China (English)

    刘雷; 王巍; 危海波; 张通; 董晋湘

    2011-01-01

    采用离子热合成方法,在草酸/四丙基溴化铵离子型低共熔混合物中对磷酸锆骨架材料的合成进行了系统地研究,通过改变反应条件合成了2种不同的磷酸锆,α-Zr(HPO4)2?H2O和(NH4)Zr2(PO4)3.体系中的四丙基季铵阳离子对磷酸锆骨架没有体现出模板作用,后者是在较高的反应温度下(220℃)以四丙基季铵离子的热分解产物(NH+4)作为模板而生成.通过向该体系中添加少量的氮杂环化合物(哌嗪),合成了一种三维开放骨架的8-元环磷酸锆微孔材料,位于孔道中的质子化哌嗪起到模板作用并平衡骨架负电荷.研究结果表明,草酸/四丙基溴化铵低共熔混合物可以作为一种离子热反应介质,通过向体系中引入少量的有机碱可以起到模板作用来诱导磷酸锆骨架的生成.%By ionothermal synthesis method,a series of syntheses have been performed in an attempt to synthesize novel zirconium phosphate materials in an oxalic acid/tetrapropyl ammonium bromide ionic eutectic mixture.The two different zirconium phosphate materials,α-Zr(HPO4)2oH2O and(NH4)Zr2(PO4)3 have been achieved by changing the synthetic conditions,tetrapropyl ammonium cation could not play its template role to form a new zirconium phosphate and the latter was synthesized at a high temperature(220 ℃) by templating the cation in situ generated from the ionothermal decomposition of the tetrapropyl ammonium(TPA) component.However,after adding a small amount of N-containing heterocyclic compound(piperazine),a known open-framework zirconium phosphate with 8-ring pore channels was obtained.The protonated piperazine not only plays a template role to form the zirconium phosphate framework but also acts as counter-ions to balance the anion framework.The used deep-eutectic solvent,therefore,can be used as an excellent ionic reaction medium to synthesize zirconium phosphate materials,the organic amine

  19. Trisodium phosphate poisoning

    Science.gov (United States)

    ... Collapse Severe change in blood acid level Shock SKIN Burns Hives Holes in the skin or tissue under the skin Skin irritation ... Camera is placed down the throat to see burns in the airways and ... exposure, the person may receive: Skin debridement (surgical ...

  20. 21 CFR 573.320 - Diammonium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Diammonium phosphate. 573.320 Section 573.320 Food... Additive Listing § 573.320 Diammonium phosphate. The food additive diammonium phosphate may be safely used... crude protein from diammonium phosphate, adequate directions for use and a prominent statement,...

  1. Inositol hexa-phosphate: a potential chelating agent for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A. [Radiobiology Laboratory, Radiation Dosimetry Unit, Department of Environment, CIEMAT, Avda Complutense 22, 28040 Madrid (Spain)

    2007-07-01

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  2. [Biodiversity of phosphate-dissolving and plant growth--promoting endophytic bacteria of two crops].

    Science.gov (United States)

    Huang, Jing; Sheng, Xiafang; He, Linyan

    2010-06-01

    We isolated and characterized phosphate-dissolving endophytic bacteria from two commonly cultivated crops. Phosphate-dissolving endophytic bacteria were isolated by plating and screening from interior tissues of rape and maize plants on NBRIP medium with tricalcium phosphate as sole phosphate source. Bacteria were characterized regarding characteristics that may be relevant for a beneficial plant-microbe interaction-indoleacetic acid, siderophore and 1-aminocyclopropane-1-carboxylic acid deaminase production,and further classified by restriction analysis of 16S rDNA. Eleven typical strains were identified by 16S rDNA sequence analysis. Thirty-two phosphate-dissolving endophytic bacteria were isolated from maize and rape plants and classified by restriction analysis of 16S rDNA in 8 different taxonomic groups at the similarity level of 76%. All the isolates could release phosphate from tricalcium phosphate and decrease the pH of the medium. The maximum phosphate content (537.6 mg/L) in the solution was obtained with strain M1L5. Thirteen isolates isolated from rape produced indoleacetic acid and siderophore, 68.4% and 63.2% of the strains isolated from maize produced indoleacetic acid and siderophore,respectively. 63.2% of the strains isolated from maize were able to grow on 1-aminocyclopropane-1-carboxylic acid as the sole nitrogen source. The eleven strains belonged to five different genera including Pantoea, Pseudomonas, Burkholderia, Acinetobacter and Ralstonia. Phosphate-dissolving endophytic bacteria isolated from rape and maize plants have abundant characteristics relative to promoting plant growth and genetic diversity.

  3. Uranium Extraction from Syrian Phosphate: A case Study

    Directory of Open Access Journals (Sweden)

    J.STAS, I. OTHMAN

    2010-12-01

    Full Text Available Uranium and trace elements were studied in few hundred samples from phosphatic formations in Syria. Uranium and trace elements were enriched in phosphorites facies compared to carbonate and siliceous facies. Uranium content of Syrian phosphorite by fission track method shows that uranium is related to the apatite mineral and organic matter. The concentration of uranium in phosphatic elements depends on the quality of these elements (grains, biogenic-elements. Further, uranium is relatively mobile during biomicritisation, coating and weathering. Investigation of uranium extraction from phosphoric acid produced at Homs plant (G.F.S by using phosphate concentrate from Khneifiss and Charquieh mines, have been carried out in a micro pilot and pilot plant scales. The result shows that the yield of uranium extraction from H3 PO4 is more than 95%.

  4. Regulation of collagen synthesis in human dermal fibroblasts by the sodium and magnesium salts of ascorbyl-2-phosphate.

    Science.gov (United States)

    Geesin, J C; Gordon, J S; Berg, R A

    1993-01-01

    Ascorbic acid has been shown to stimulate collagen synthesis in dermal fibroblasts by increasing the rate of transcription of collagen genes. Experiments involving the use of ascorbic acid require daily supplementation due to the instability of the molecule in aqueous solutions. In order to provide a more stable alternative to ascorbic acid, two salts of ascorbyl-2-phosphate, having a greater chemical stability than ascorbic acid, were tested for their ability to stimulate collagen synthesis in monolayer fibroblast cultures. The concentration and time dependence of their activities were compared with ascorbic acid. The magnesium salt of ascorbyl-2-phosphate was found to be equivalent to ascorbic acid in stimulating collagen synthesis in these assays, while the sodium salt required at least a tenfold greater concentration to produce the same effect as ascorbic acid. Solutions of either ascorbic acid or the ascorbyl-2-phosphate analogs (at 10 mM) in phosphate-buffered saline (PBS) were relatively stable as shown by their decay rates and their ability to stimulate collagen synthesis even after nine days in solution prior to testing their effects on cultured cells. Ascorbic acid was unstable at neutral pH compared to solutions of either sodium or magnesium ascorbyl-2-phosphate. These data support the use of magnesium ascorbyl-2-phosphate in experiments where stability of ascorbic acid is a concern, e.g. in long-term cultures or in in vivo studies.

  5. Isolation of phosphatase-producing phosphate solubilizing bacteria from Loriya hot spring: Investigation of phosphate solubilizing in the presence of different parameters

    Directory of Open Access Journals (Sweden)

    Maryam Parhamfar

    2014-04-01

    Full Text Available Introduction: Biofertilizers are the microorganisms that can convert useless nutrient to usable compounds. Unlike fertilizer, cost of biofertilizer production is low and doesn’t produce ecosystem pollution. Phosphate fertilizers can be replaced by phosphate biofertilizer to produce improvement. So, it is necessary to screen the climate-compatible phosphate solubilizing bacteria. Materials and methods: In this project samples were picked up from Loriya hot spring, which are located in Jiroft. Samples were incubated in PKV medium for 3 days. Screening of phosphate solubilizing bacteria was performed on the specific media, based on clear area diameter. The best bacterium was identified based on 16s rDNA gene. Phosphate solubilizing activity of this strain was considered in different carbon, nitrogen, phosphate and pH sources. Results: Sequence alignment and phylogenetic tree results show that B. sp. LOR033 is closely related to Bacillus licheniformis, with 97% homology. In addition, results show that maximum enzyme production was performed after 2 days that incubation pH was decreased simultaneously when the time was increased. Carbon sources investigation show that glucose is the most appropriate in enzyme production and phosphate releasing. Furthermore, results show that the optimum initial pH for phytase production was pH5.0. Different phosphate sources show that tricalcium phosphate has the suitable effect on enzyme activity in three days of incubation. Discussion and conclusion: Phosphatase enzyme production capacity, growth in acidic pH and phosphate solubilizing potential in different salt and phosphate sources show that this strain has considerable importance as biofertilizers.

  6. Distribution of potentially toxic elements in the Brazilian phosphogypsum and phosphate fertilizers

    Directory of Open Access Journals (Sweden)

    Saueia C. H. R.

    2013-04-01

    Full Text Available The Brazilian phosphate fertilizer is obtained by wet reaction of the igneous phosphate rock with concentrated sulphuric acid, giving as final product phosphoric acid and dehydrated calcium sulphate (phosphogypsum as by-product. Phosphoric acid is the raw material for the production of phosphate fertilizers (SSP, TSP, MAP and DAP. Phosphogypsum waste is stored in stacks, since its level of impurities (metals and radionuclides among others prevent its safe reutilization. However, part of this waste is used to improve fertility of agricultural soils. The main aim of this paper is to determine the levels of potentially toxic elements in phosphate fertilizers and phosphogypsum produced in Brazil. The elements Co and Cr were analyzed by instrumental neutron activation analysis and As, Cd, Cu, Hg, Ni, Pb, Se and Zn were analyzed by ICP-OES. The results obtained are lower than the limits established by the Brazilian regulatory agency for metals in fertilizers and soil conditioner.

  7. Synthesis and controllable wettability of micro- and nanostructured titanium phosphate thin films formed on titanium plates.

    Science.gov (United States)

    Yada, Mitsunori; Inoue, Yuko; Sakamoto, Ayako; Torikai, Toshio; Watari, Takanori

    2014-05-28

    The hydrothermal treatment of a titanium plate in a mixed aqueous solution of hydrogen peroxide and aqueous phosphoric acid under different conditions results in the formation of various titanium phosphate thin films. The films have various crystal structures such as Ti2O3(H2PO4)2·2H2O, α-titanium phosphate (Ti(HPO4)2·H2O), π-titanium phosphate (Ti2O(PO4)2·H2O), or low-crystallinity titanium phosphate and different morphologies that have not been previously reported such as nanobelts, microflowers, nanosheets, nanorods, or nanoplates. The present study also suggests the mechanisms behind the formation of these thin films. The crystal structure and morphology of the titanium phosphate thin films depend strongly on the concentration of the aqueous hydrogen peroxide solution, the amount of phosphoric acid, and the reaction temperature. In particular, hydrogen peroxide plays an important role in the formation of the titanium phosphate thin films. Moreover, controllable wettability of the titanium phosphate thin films, including superhydrophilicity and superhydrophobicity, is reported. Superhydrophobic surfaces with controllable adhesion to water droplets are obtained on π-titanium phosphate nanorod thin films modified with alkylamine molecules. The adhesion force between a water droplet and the thin film depends on the alkyl chain length of the alkylamine and the duration of ultraviolet irradiation utilized for photocatalytic degradation.

  8. Oxygen isotopic substitution of peptidyl phosphates for modification-specific mass spectrometry.

    Science.gov (United States)

    Shi, Yu; Yao, Xudong

    2007-11-15

    The first method of isotopic substitution of a nonbridging oxygen atom in pre-existing phosphates on peptides is reported, solving a long-standing, challenging issue in the sample preparation of phosphopeptides. Peptidyl phosphates, phosphate groups on phosphopeptides, are converted to phosphoramidates with carbodiimide assistance. Acid-catalyzed hydrolysis of the newly formed phosphoramidates incorporates one oxygen atom from H2(16)O or H2(18)O, producing peptidyl phosphates-16O1 or -18O1, respectively. The oxygen labels are stable under common separation and analysis conditions. This labeling method causes minimal structural alteration to peptidyl phosphates and allows the direct application of established phosphate-specific marker ions to the mass spectrometric analysis of differentially labeled phosphopeptide pairs. Using phosphotyrosinyl peptides as model analytes, the characteristic 16O1- and 18O1-labeled phosphotyrosine immonium ions at m/z 216.043 and 218.047 are used for developing a method of phosphopeptide quantitation that is independent of the amino acid sequence of the peptides. From analysis by tandem parallel fragmentation mass spectrometry, it is clear that the phosphate-specific marker ions authentically inherit the quantitative information from precursor phosphopeptides. The dynamic range for relative quantitation of differentially labeled phosphopeptides is at least 2 orders of magnitude for experiments run on a quadrupole time-of-flight mass spectrometer. The use of 16O1 and 18O1 labeling for counting the number of phosphate groups on peptides is also demonstrated.

  9. Determination of 14 monoalkyl phosphates, dialkyl phosphates and dialkyl thiophosphates by LC-MS/MS in human urinary samples.

    Science.gov (United States)

    Reemtsma, Thorsten; Lingott, Jana; Roegler, Stefanie

    2011-04-15

    Human urine was analyzed for nine dialkyl (DAP) and five monoalkyl phosphates (MAP) by LC-MS/MS. Some phosphoric acid esters are industrial chemicals and other hydrolysis products of trialkyl or triaryl phosphates, used as pesticides, flame retardants or plasticizers. Five MAP and two DAP were detected here for the first time in human urine. Monobutyl, diethyl, diphenyl and diethylhexyl phosphate were determined with median concentrations in the μg/L-range. The total urinary concentration of the 14 DAP and MAP summed up to a median of 20μg/L. Inclusion of MAP in future biomonitoring studies should provide a more comprehensive picture of the exposure of humans to organophosphorus compounds.

  10. Gene Cloning of Iranian Leishmania major Mannose-1-Phosphate Guanyltransferase

    Directory of Open Access Journals (Sweden)

    R Salehi

    2009-07-01

    Full Text Available "nBackground: Leishmania is an obligatory intracellular protozoan parasite, which infects human be­ings when infected sand fly vector takes a blood meal.  Most efforts are towards designing an effective vaccine to prevent leishmaniasis. In this way, development of candidate antigen for vaccine has spe­cial im­portant. In this study, we cloned mannose-1-phosphate guanyltransferase gene of Iranian L .major in pET32a expression vector. "nMethods: Primers based on L. major mannose-1-phosphate guanyltransferase sequence gene was de­signed and synthesized. DNA of Leishmania promastigotes was extracted and PCR reaction was done. PCR product was cloned into pTZ57R and sub cloned into pET32a expression vector. "nResults: Recombinant plasmid containing 1140 bp as L. major mannose-1-phosphate guanyltrans­ferase gene was extracted and confirmed by restriction analysis. PCR product was sequenced and de­posited to GenBank. There were some differences in amino acid sequences between Iranian L. major mannose-1-phosphate guanyltransferase and others previously accepted in GenBank "nConclusion: We amplified and cloned Iranian L. major mannose-1-phosphate guanyltransferase successfully.

  11. Phosphate-solubilising rhizobacteria associated with Coffea arabica L. in natural coffee forests of southwestern Ethiopia

    Directory of Open Access Journals (Sweden)

    Diriba Muleta

    2013-01-01

    Full Text Available Phosphate-solubilising rhizobacteria associated with Coffea arabica L. in natural coffee forests of southwestern Ethiopia were investigated. The main purpose was to screen for potential microbial biofertilisers by assessing isolated strains for phosphate solubilisation efficiency and organic acid production in different media. Initial screening was performed on Pikovskaya’s agar (PA. Quantitative colorimetric estimations of mobilised phosphate were made in different broth media in the presence of two phosphate sources. HPLC was employed for the detection of organic acids. From a total of 395 rhizobacterial isolates tested for P solubilisation, over 72% (mostly Pseudomonas spp. formed visible dissolution haloes on PA. Two Erwinia species and a P. chlororaphis strain produced the largest solubilisation indices and also solubilised hydroxyapatite strongly in broth medium. Solubilisation of hydroxyapatite (HAP/tricalcium phosphate (TCP by all isolates coincided with a decrease in medium pH. HPLC analyses of culture supernatants confirmed the presence of several organic acids, with 2-ketogluconic acid dominating. The production of organic acids by these coffee-associated phosphobacteria could be considered the major mechanism involved in the solubilisation of insoluble HAP/TCP. Certain isolates deserve particular attention for bioinoculant development due to their remarkable efficiency of insoluble phosphate solubilisation. The present study could therefore be important with respect to screening of Coffea arabica-associated rhizobacteria that possess direct plant growth-promoting traits for extending the use of indigenous microbes as microbial biofertilisers.

  12. Phosphate enhances Fgf23 expression through reactive oxygen species in UMR-106 cells.

    Science.gov (United States)

    Hori, Michiko; Kinoshita, Yuka; Taguchi, Manabu; Fukumoto, Seiji

    2016-03-01

    Fibroblast growth factor 23 (FGF23) has been shown to work as a phosphotropic hormone. Although FGF23 reduces the serum phosphate level, it has not been established that phosphate directly regulates FGF23 production. In this study, we investigated whether phosphate can enhance Fgf23 expression using the rat osteoblastic cell line UMR-106, which has been shown to express Fgf23 in response to 1,25-dihydroxyvitamin D [1,25(OH)2D]. Phosphate increased Fgf23 expression in a dose- and time-dependent manner in the presence of 1,25(OH)2D. Phosphate also increased Fgf23 promoter activity, but showed no effect on the half-life of Fgf23 messenger RNA. Phosphonoformic acid and PD98059, an inhibitor of MEK, inhibited the effects of phosphate on Fgf23 expression and promoter activity. In addition, phosphate enhanced production of reactive oxygen species (ROS) in UMR-106 cells, and hydrogen peroxide enhanced FGF23 production in a dose- and time-dependent manner. Hydrogen peroxide also enhanced Elk1 reporter activity, a target of the MEK-extracellular-signal-regulated kinase (ERK) pathway. Furthermore, the effect of phosphate on ROS production and Fgf23 expression was inhibited by apocynin, an inhibitor of NADPH oxidase. These results indicate that phosphate directly enhances Fgf23 transcription without affecting the stability of Fgf23 messenger RNA by stimulating NADPH-induced ROS production and the MEK-ERK pathway in UMR-106 cells.

  13. Studies on Anion Promoted Titania.1: Preparation, Characterization, and Catalytic Activity toward Alcohol and Cumene Conversion Reactions of Phosphated Titania.

    Science.gov (United States)

    Parida; Acharya; Samantaray; Mishra

    1999-09-15

    Phosphate impregnated titania samples with varying amount of phosphate have been prepared by solid-solid kneading as well as aqueous impregnation method. All the samples are characterized by XRD, TG-DTA, and N(2) adsorption-desorption isotherm. Surface area is found to increase with the increase in phosphate content up to 7.5 wt% loading and thereafter decreases. The average pore diameter and crystallite size of titania decreases with the addition of phosphate. However, total acidity (determined by base adsorption method) and the catalytic activity increases with the increase in phosphate content up to 10 wt%. Phosphated samples prepared using phosphoric acid as the source of phosphate exhibit higher acidity compared to the samples prepared using (NH(4))(3)PO(4). However, the sample prepared from (NH(4))(3)PO(4) shows the presence of both acid and basic sites. Though from the cumene conversion study it is understood that phosphated samples contain both Lewis and Brønsted acid sites, the latter predominates over the former. Copyright 1999 Academic Press.

  14. Homo-D-lactic acid fermentation from arabinose by redirection of the phosphoketolase pathway to the pentose phosphate pathway in L-lactate dehydrogenase gene-deficient Lactobacillus plantarum.

    Science.gov (United States)

    Okano, Kenji; Yoshida, Shogo; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko

    2009-08-01

    Optically pure d-lactic acid fermentation from arabinose was achieved by using the Lactobacillus plantarum NCIMB 8826 strain whose l-lactate dehydrogenase gene was deficient and whose phosphoketolase gene was substituted with a heterologous transketolase gene. After 27 h of fermentation, 38.6 g/liter of d-lactic acid was produced from 50 g/liter of arabinose.

  15. ZIRCONIUM PHOSPHATE ADSORPTION METHOD

    Science.gov (United States)

    Russell, E.R.; Adamson, A.S.; Schubert, J.; Boyd, G.E.

    1958-11-01

    A method is presented for separating plutonium values from fission product values in aqueous acidic solution. This is accomplished by flowing the solutlon containing such values through a bed of zirconium orthophosphate. Any fission products adsorbed can subsequently be eluted by washing the column with a solution of 2N HNO/sub 3/ and O.lN H/sub 3/PO/sub 4/. Plutonium values may subsequently be desorbed by contacting the column with a solution of 7N HNO/sub 3/ .

  16. Autohydrolysis of phytic acid.

    Science.gov (United States)

    Hull, S R; Gray, J S; Montgomery, R

    1999-09-10

    The autohydrolysis of phytic acid at 120 degrees C resulted in the formation of most of the phosphate esters of myo-inositol in varying amounts depending upon the reaction time. Eighteen of the 39 chromatographically distinct myo-inositol mono-, bis-, tris-, tetrakis-, pentakis-, and hexakisphosphates have been characterized using two different HPLC systems. These myo-inositol phosphates were partially purified by preparative anion-exchange chromatography under acidic and alkaline elution conditions. The combination of these two methods provides a two-tiered chromatographic approach to the rapid and sensitive identification of inositol phosphates in complex mixtures. Identification of the products was confirmed by 1D and 2D (1)H NMR analysis. The analytical procedure was applied to the autohydrolysis of the mixture of inositol phosphates from corn steep water.

  17. Could organic phosphorus compounds contaminate the analysis of phosphate oxygen isotopes in freshwater matrices?

    Science.gov (United States)

    Davies, Ceri; Surridge, Ben; Gooddy, Daren

    2014-05-01

    Variation in the stable isotope composition of oxygen within dissolved phosphate (δ18Op) represents a novel and potentially powerful environmental tracer, providing insights into the sources of phosphorus and the extent to which phosphorus from different sources is metabolised. The analysis of δ18Opwithin freshwater matrices requires isolation of the phosphate ion from possible sources of contaminant oxygen within the bulk matrix, prior to pyrolysis (usually of a silver phosphate precipitate) and analysis of the oxygen isotope composition. The majority of published research uses co-precipitation of phosphate with brucite (Mg(OH)2) as an initial step in the isolation of the phosphate ion. However, freshwater matrices also contain a wide range of organic phosphorus compounds, including adenosine 5'-triphosphate (ATP) and phosphonates such as 2-aminoethylphosphonic acid. In this paper, we initially examine the potential for co-precipitation of organic phosphorus compounds with brucite. Our data indicate that ATP, sodium pyrophosphate and inositol hexakisphosphate are almost entirely removed from solution through co-precipitation with brucite, whilst glucose-6-phosphate and 2-aminoethylphosphonic acid are less readily co-precipitated. Subsequently, we assessed the potential for acid-hydrolysis of organic phosphorus compounds during re-dissolution of the brucite precipitate, using a range of acid systems. Our data indicate that up to 17% of ATP and up to 5% of sodium pyrophosphate can be hydrolysed by concentrated acetic acid, yielding fresh phosphate ions in solution. Our findings have potentially significant implications for analysis of δ18Opbecause the fresh phosphate ions produced following acid hydrolysis will be subjected to inheritance and kinetic isotope fractionations, likely altering the bulk δ18Op within a freshwater sample.

  18. Constant composition dissolution of mixed phases. II. Selective dissolution of calcium phosphates.

    Science.gov (United States)

    Tang, Ruikang; Hass, Michael; Wu, Wenju; Gulde, Stacey; Nancollas, George H

    2003-04-15

    Characterization of the dissolution kinetics of individual synthetic and biological calcium phosphates is of considerable importance since these phases often coexist in biological minerals. The constant composition method has been used to study the dissolution kinetics of a series of synthetic calcium phosphates, brushite (DCPD), beta-tricalcium phosphate (TCP), octacalcium phosphate (OCP), hydroxyapatite (HAP), and carbonated apatite (CAP) in the presence and absence of citric acid, as a function of pH and thermodynamic driving force. While citric acid markedly accelerates the dissolution of TCP, HAP dissolution is significantly inhibited. Moreover, this additive has almost no influence on the dissolution of DCPD, OCP, and CAP. Dual constant composition dissolution studies of mixed calcium phosphates in the presence of citric acid have also been made. Another factor, pH, also plays an important role in the dissolution of these calcium phosphates. In suspensions of calcium phosphate mixtures, specific phases can be selectively dissolved by changing experimental parameters such as pH and the presence of rate modifiers. This result has important applications for the dissolution control of dental hard tissues such as dentin, enamel, and calculus.

  19. Mechanisms for solubilization of various insoluble phosphates and activation of immobilized phosphates in different soils by an efficient and salinity-tolerant Aspergillus niger strain An2.

    Science.gov (United States)

    Li, Xiaolong; Luo, Lijin; Yang, Jinshui; Li, Baozhen; Yuan, Hongli

    2015-03-01

    Mechanisms for solubilization of different types of phosphates and activation of immobilized phosphates in different types of soils by an efficient fungal strain An2 were explored and evaluated in this study. An2 was isolated from a Chinese cabbage rhizosphere soil and identified as Aspergillus niger. It could fast release up to 1722, 2066, and 2356 mg L(-1) of soluble phosphorus (P) from 1 % Ca3(PO4)2, Mg3(PO4)2, and AlPO4 (Ca-P, Mg-P, and Al-P) and 215 and 179 mg L(-1) from 0.5 % FePO4 and rock phosphate (Fe-P and RP), respectively. HPLC assay demonstrated that An2 mainly secreted oxalic acid to solubilize Ca-P, Mg-P, Al-P, and Fe-P whereas secreted tartaric acid to solubilize RP. Furthermore, An2 could tolerate salinity up to 4 % NaCl without impairing its phosphate-solubilizing ability. The simulation experiments validated that An2 was able to effectively activate immobilized phosphates in general calcareous, acidic, as well as saline-alkali soils with high total P content. This study shows new insights into the mechanisms for microbial solubilization of different types of phosphates and supports the future application of strain An2 in different types of soils to effectively activate P for plants.

  20. Uranium recovery from Uro area phosphate ore, Nuba Mountains, Sudan

    Directory of Open Access Journals (Sweden)

    Abdelmajid A. Adam

    2014-11-01

    Full Text Available This study was carried out in a laboratory scale to recover uranium from Uro area phosphate ore in the eastern part of Nuba Mountains in Sudan. Phosphate ore samples were collected, and analyzed for uranium abundance. The results showed that the samples contain a significant concentration of uranium with an average of 310.3 μg/g, which is 2.6 times higher than the world average of phosphate. The green phosphoric acid obtained from the samples was found to contain uranium in the range of 186–2049 μg/g, with an average of 603.3 μg/g, and about 98% of uranium content of the phosphate ore was rendered soluble in the phosphoric acid. An extraction process using 25% tributylphosphate, followed by stripping process using 0.5 M sodium carbonate reported that more than 98% of uranium in the green phosphoric acid exists as uranyl tricarbonate complex, moreover, sodic decomposition using 50% sodium hydroxide showed that about 98% of the uranium was precipitated as sodium diuranate concentrate that is known as the yellow cake (Na2U2O7. Further purification and calcinations of the yellow cake led to the formation of the orange powder of uranium trioxide (UO3. The chemical analysis of the obtained uranium concentrates; yellow cake and uranium trioxide proved their nuclear purity and that they meet the standard commercial specification. The obtained results proved that uranium from Uro phosphate ore was successfully recovered as uranium trioxide with an overall recovery percentage of 93%.

  1. Synthesis, characterization and photocatalytic reactions of phosphated mesoporous titania

    Indian Academy of Sciences (India)

    Pallabi Goswami; Jatindra Nath Ganguli

    2012-10-01

    Mesoporous titania nanoparticles with a well-definedmesostructure was prepared by hydrothermal process, using nonionic triblock copolymer P123 as surfactant template, modified with phosphoric acid and followed by calcination at 600°C. The sol–gel titania was modified by in situ phosphorylation using phosphoric acid and thereby incorporating phosphorous directly into the framework of TiO2. The resulting materials were characterized by XRD, SEM, TEM, nitrogen adsorption, TGA and DRS. It was found that the structural and optical properties of titania samples are strongly influenced by their phosphate modification. In case of calcined samples a positive effect on the specific surface area for the in situ phosphated sample was found. Mesoporous structure of phosphated titania did not collapse even after calcination at 600°C. The enhanced photocatalytic activity of the synthesized phosphate nanomaterials were evaluated through a study of the decomposition of fluorescein under UV light excitation and compared with undoped titania nanomaterial as well as with commercial titania.

  2. A Novel Approach to Bioleach Soluble Phosphorus from Rock Phosphate

    Institute of Scientific and Technical Information of China (English)

    池汝安; 肖春桥; 黄晓慧; 王存文; 吴元欣

    2007-01-01

    A novel approach to bioleach soluble phosphorus from rock phosphate, involving the bio-oxidation of pyrite by adaptated Acidithiobacillus ferrooxidans (At. f) and the product of sulfuric acid to dissolve rock phosphate, has been proposed in this paper. The soluble phosphorus could be leached more effectively in the presence of pyrite by At. f than that leached directly by sulfuric acid. The optimal technological parameters are presented. The highest phosphorus leaching rate is 9.00% when the culture substrate is the mixture of FeSO4·7H2O and pyrite, the phosphorus leaching rate is 8.00% when the initial pH and culture time are 2.5 and 5 d, respectively. The optimal rock phosphate particle size is 0.05 mm for the leaching of phosphorus. The bigger the grains of pyrite, the lower the phosphorus leaching rate. The bacterium At. f should be appropriately adaptated, which makes it easier to bioleach soluble phosphorus from rock phosphate.

  3. The chemistry of tributyl phosphate at elevated temperatures in the Plutonium Finishing Plant Process Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.; Cooper, T.D.

    1994-06-01

    Potentially violent chemical reactions of the tributyl phosphate solvent used by the Plutonium Finishing Plant at the Hanford Site were investigated. There is a small probability that a significant quantity of this solvent could be accidental transferred to heated process vessels and react there with nitric acid or plutonium nitrate also present in the solvent extraction process. The results of laboratory studies of the reactions show that exothermic oxidation of tributyl phosphate by either nitric acid or actinide nitrates is slow at temperatures expected in the heated vessels. Less than four percent of the tributyl phosphate will be oxidized in these vented vessels at temperatures between 125{degrees}C and 250{degrees}C because the oxidant will be lost from the vessels by vaporization or decomposition before the tributyl phosphate can be extensively oxidized. The net amounts of heat generated by oxidation with concentrated nitric acid and with thorium nitrate (a stand-in for plutonium nitrate) were determined to be about -150 and -220 joules per gram of tributyl phosphate initially present, respectively. This is not enough heat to cause violent reactions in the vessels. Pyrolysis of the tributyl phosphate occurred in these mixtures at temperatures of 110{degrees}C to 270{degrees}C and produced mainly 1-butene gas, water, and pyrophosphoric acid. Butene gas generation is slow at expected process vessel temperatures, but the rate is faster at higher temperatures. At 252{degrees}C the rate of butene gas generated was 0.33 g butene/min/g of tributyl phosphate present. The measured heat absorbed by the pyrolysis reaction was 228 J/g of tributyl phosphate initially present (or 14.5 kcal/mole of tributyl phosphate). Release of flammable butene gas into process areas where it could ignite appears to be the most serious safety consideration for the Plutonium Finishing Plant.

  4. Phosphate-solubilizing bacteria associated with runner bean rhizosphere

    Directory of Open Access Journals (Sweden)

    Mihalache Gabriela

    2015-01-01

    Full Text Available Soil microorganisms, especially rhizobacteria, play a key role in soil phosphorus (P dynamics and the subsequent availability of phosphate to plants. Utilization of phosphate-solubilizing bacteria as biofertilizers instead of synthetic chemicals is known to improve plant growth through the supply of plant nutrients, and may help to sustain environmental health and soil productivity. The main purpose of this study was to identify new phosphate-solubilizing bacteria isolated from runner bean rhizosphere. Ten out of 25 isolated bacterial strains solubilized Ca3(PO42 in qualitative and quantitative P-solubilization. The strain that exhibited the highest potential to solubilize Ca3(PO42, was selected for further determination of the mechanisms involved in the process. The medium pH was measured, organic acids released in the culture medium were identified by HPLC analysis, and the acid and alkaline phosphatase activities were determined. Our results showed that strain R7 solubilized phosphorous through the production of various organic acids such as lactic, isocitric, tartaric and pyruvic acids, and that it can be used as a potential biofertilizer.

  5. Final Report: Dominant Mechanisms of Uranium-Phosphate Reactions in Subsurface Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, Jeffrey G. [Washington Univ., St. Louis, MO (United States); Giammar, Daniel E. [Washington Univ., St. Louis, MO (United States); Wang, Zheming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-08

    Phosphate addition is an in situ remediation approach that may enhance the sequestration of uranium without requiring sustained reducing conditions. However, the geochemical factors that determine the dominant immobilization mechanisms upon phosphate addition are insufficiently understood to design efficient remediation strategies or accurately predict U(VI) transport. The overall objective of our project is to determine the dominant mechanisms of U(VI)-phosphate reactions in subsurface environments. Our research approach seeks to determine the U(VI)-phosphate solid that form in the presence of different groundwater cations, characterize the effects of phosphate on U(VI) adsorption and precipitation on smectite and iron oxide minerals, examples of two major reactive mineral phases in contaminated sediments, and investigate how phosphate affects U(VI) speciation and fate during water flow through sediments from contaminated sites. The research activities conducted for this project have generated a series of major findings. U(VI) phosphate solids from the autunite mineral family are the sole phases to form during precipitation, with uranyl orthophosphate not occurring despite its predicted greater stability. Calcium phosphates may take up substantial quantities of U(VI) through three different removal processes (adsorption, coprecipitation, and precipitation) but the dominance of each process varies with the pathway of reaction. Phosphate co-adsorbs with U(VI) onto smectite mineral surfaces, forming a mixed uranium-phosphate surface complex over a wide range of conditions. However, this molecular-scale association of uranium and phosphate has not effect on the overall extent of uptake. In contrast, phosphate enhanced U(VI) adsorption to iron oxide minerals at acidic pH conditions but suppresses such adsorption at neutral and alkaline pH, despite forming mixed uranium-phosphate surface complexes during adsorption. Nucleation barriers exist that inhibit U(VI) phosphate

  6. [Phosphate metabolism and iron deficiency].

    Science.gov (United States)

    Yokoyama, Keitaro

    2016-02-01

    Autosomal dominant hypophosphatemic rickets(ADHR)is caused by gain-of-function mutations in FGF23 that prevent its proteolytic cleavage. Fibroblast growth factor 23(FGF23)is a hormone that inhibits renal phosphate reabsorption and 1,25-dihydroxyvitamin D biosynthesis. Low iron status plays a role in the pathophysiology of ADHR. Iron deficiency is an environmental trigger that stimulates FGF23 expression and hypophosphatemia in ADHR. It was reported that FGF23 elevation in patients with CKD, who are often iron deficient. In patients with nondialysis-dependent CKD, treatment with ferric citrate hydrate resulted in significant reductions in serum phosphate and FGF23.

  7. Thermal Decomposition of Nitrated Tributyl Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Paddleford, D.F. [Westinghouse Savannah River Company, Aiken, SC (United States); Hou, Y.; Barefield, E.K.; Tedder, D.W.; Abdel-Khalik, S.I. [Georgia Institute of Technology, GA (United States)

    1995-01-01

    Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ``red oil`` explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material.

  8. Improved production of homo-D-lactic acid via xylose fermentation by introduction of xylose assimilation genes and redirection of the phosphoketolase pathway to the pentose phosphate pathway in L-Lactate dehydrogenase gene-deficient Lactobacillus plantarum.

    Science.gov (United States)

    Okano, Kenji; Yoshida, Shogo; Yamada, Ryosuke; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko

    2009-12-01

    The production of optically pure d-lactic acid via xylose fermentation was achieved by using a Lactobacillus plantarum NCIMB 8826 strain whose l-lactate dehydrogenase gene was deficient and whose phosphoketolase genes were replaced with a heterologous transketolase gene. After 60 h of fermentation, 41.2 g/liter of d-lactic acid was produced from 50 g/liter of xylose.

  9. Intermediates in the transformation of phosphonates to phosphate by bacteria.

    Science.gov (United States)

    Kamat, Siddhesh S; Williams, Howard J; Raushel, Frank M

    2011-11-16

    Phosphorus is an essential element for all known forms of life. In living systems, phosphorus is an integral component of nucleic acids, carbohydrates and phospholipids, where it is incorporated as a derivative of phosphate. However, most Gram-negative bacteria have the capability to use phosphonates as a nutritional source of phosphorus under conditions of phosphate starvation. In these organisms, methylphosphonate is converted to phosphate and methane. In a formal sense, this transformation is a hydrolytic cleavage of a carbon-phosphorus (C-P) bond, but a general enzymatic mechanism for the activation and conversion of alkylphosphonates to phosphate and an alkane has not been elucidated despite much effort for more than two decades. The actual mechanism for C-P bond cleavage is likely to be a radical-based transformation. In Escherichia coli, the catalytic machinery for the C-P lyase reaction has been localized to the phn gene cluster. This operon consists of the 14 genes phnC, phnD, …, phnP. Genetic and biochemical experiments have demonstrated that the genes phnG, phnH, …, phnM encode proteins that are essential for the conversion of phosphonates to phosphate and that the proteins encoded by the other genes in the operon have auxiliary functions. There are no functional annotations for any of the seven proteins considered essential for C-P bond cleavage. Here we show that methylphosphonate reacts with MgATP to form α-D-ribose-1-methylphosphonate-5-triphosphate (RPnTP) and adenine. The triphosphate moiety of RPnTP is hydrolysed to pyrophosphate and α-D-ribose-1-methylphosphonate-5-phosphate (PRPn). The C-P bond of PRPn is subsequently cleaved in a radical-based reaction producing α-D-ribose-1,2-cyclic-phosphate-5-phosphate and methane in the presence of S-adenosyl-L-methionine. Substantial quantities of phosphonates are produced worldwide for industrial processes, detergents, herbicides and pharmaceuticals. Our elucidation of the chemical steps for the

  10. Photorelease of phosphates: Mild methods for protecting phosphate derivatives

    Directory of Open Access Journals (Sweden)

    Sanjeewa N. Senadheera

    2014-08-01

    Full Text Available We have developed a new photoremovable protecting group for caging phosphates in the near UV. Diethyl 2-(4-hydroxy-1-naphthyl-2-oxoethyl phosphate (14a quantitatively releases diethyl phosphate upon irradiation in aq MeOH or aq MeCN at 350 nm, with quantum efficiencies ranging from 0.021 to 0.067 depending on the solvent composition. The deprotection reactions originate from the triplet excited state, are robust under ambient conditions and can be carried on to 100% conversion. Similar results were found with diethyl 2-(4-methoxy-1-naphthyl-2-oxoethyl phosphate (14b, although it was significantly less efficient compared with 14a. A key step in the deprotection reaction in aq MeOH is considered to be a Favorskii rearrangement of the naphthyl ketone motif of 14a,b to naphthylacetate esters 25 and 26. Disruption of the ketone-naphthyl ring conjugation significantly shifts the photoproduct absorption away from the effective incident wavelength for decaging of 14, driving the reaction to completion. The Favorskii rearrangement does not occur in aqueous acetonitrile although diethyl phosphate is released. Other substitution patterns on the naphthyl or quinolin-5-yl core, such as the 2,6-naphthyl 10 or 8-benzyloxyquinolin-5-yl 24 platforms, also do not rearrange by aryl migration upon photolysis and, therefore, do not proceed to completion. The 2,6-naphthyl ketone platform instead remains intact whereas the quinolin-5-yl ketone fragments to a much more complex, highly absorbing reaction mixture that competes for the incident light.

  11. Formation of hydroxyapatite in hydrogels from tetracalcium phosphate/dicalcium phosphate mixtures.

    Science.gov (United States)

    Sugawara, A; Antonucci, J M; Takagi, S; Chow, L C; Ohashi, M

    1989-03-01

    Apatitic calcium phosphate cements, formed by the ambient reaction of tetracalcium phosphate (TTCP) with dicalcium phosphates (DCP), have been recently reported. H2O or dilute aq. H3PO4 (0.2%) is used as the liquid vehicle for this reaction. The aim of this study was to ascertain if hydroxyapatite (HAp) can form in self-cured hydrogel composites containing TTCP/DCP mixes. The setting times (ST) and diametral tensile strengths (DTS) of these hydrogel composites were also determined. The hydrogels were of two types: (1) vinyl thermosets derived from the copolymerization of HEMA (2-hydroxyethyl methacrylate) and cross-linking monomers, and (2) polyelectrolyte-based hydrogels formed from aq. poly(alkenoic acids), e.g., poly(acrylic acid). Cylindrical specimens 6 mm D x 3 mm H were prepared and stored in H2O for up to 30 days. The HEMA composites were hardened in 7-15 min by free radical initiation (benzoyl peroxide/tertiary aromatic amine). The polyelectrolyte cements were hardened in 6-8 min. After various periods of storage in H2O at 37 degrees C, some of the specimens were examined by X-ray spectroscopy for HAp. HAp formation was not observed in the HEMA composites even after 30 days of H2O storage but was detected in the polyacid cements. The 24-h DTS values of the HEMA composites (14-26 MPa) were higher than those of the polyacid cements (7-12 MPa). Both the H2O content and pH may thus be factors controlling the rate and extent of HAp formation in hydrogel composites containing TTCP/DCP mixtures.

  12. Cloning and characterization of a glucose 6-phosphate/phosphate translocator from Oryza sativa

    Institute of Scientific and Technical Information of China (English)

    姜华武; 佃蔚敏; 刘非燕; 吴平

    2003-01-01

    Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator (GPT) was isolated from a cDNA library of immature seeds of rice and named as OsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit poptide consisting of 70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked