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Sample records for n-phenyl oxalic dihydrazide

  1. 40 CFR 721.10057 - Dodecanedioic acid, 1, 12-dihydrazide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dodecanedioic acid, 1, 12-dihydrazide... Specific Chemical Substances § 721.10057 Dodecanedioic acid, 1, 12-dihydrazide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanedioic acid, 1,...

  2. First cascade Mitsunobu reactions for the synthesis of 2-benzoxazole-N-phenyl and 2-benzimidazole-N-phenyl derivatives.

    Science.gov (United States)

    Yan, Yu; Zhong, Qifei; Zhao, Nan; Liu, Gang

    2012-02-01

    An efficient method has been developed via cascade Mitsunobu reactions to synthesize 2-benzoxazole-N-phenyl and 2-benzimidazole-N-phenyl derivatives, which are common structural motifs in medicinal chemistry. This method also provides a new application of the Mitsunobu reaction.

  3. N-Phenyl-N'-ethoxycarbonyl-thiourea

    Institute of Scientific and Technical Information of China (English)

    XIAN Liang; LIN Qi; ZHANG You-ming; WEI Tai-bao

    2004-01-01

    Thiourea compounds are excellent bioactive agents. A number of biological activities are associated with substituted thiourea derivatives, and some N-substituted-N'-alkoxycarbonyl-thiourea have been used as antifungal agents. On the other hand, N-substituted-N'-alkoxycarbonyl-thiourea have attracted considerable attention in recent years because of its coordination ability with transition metal ions such as Cu(Ⅰ), Zn(Ⅱ) and Cd(Ⅱ).As a part of our works in researching coordination behaviours, synthesis and biological activities of N-substituted-N'-alkoxycarbonyl-thiourea, the present work was reported on the crystal structure of N-phenyl-N'- ethoxycarbonyl-thiourea.Fig. 1 Molecular structure of the title compound Fig. 2 Packing diagram of molecules shows the hydrogen bond intermolecular contacts.Ethyl chloroformate was treated with potassium thiocyanate in ethyl acetate under the condition of solid-liquid phase transfer catalysis using 3% polyethylene glycol-400 as the catalyst to give the corresponding ethoxycarbonyl isothiocyanate, which was reacted with aniline to give the title compound. The solid was separated from the liquid phase by filtration, washed with ethyl acetate and then dried in air. The single crystals of the title compound was obtained by the slow evaporation of its ethanol solution after 2 weeks, one of them was selected optically for the diffraction study and glued to a glass fibre.The crystals structure in the triclinic system and space group of P-1 of N-phenyl-N'-ethoxycarbonyl-thiourea was determined from single-crystal X-ray diffraction analysis,a = 5.787 (1) A, b = 10.218 (2) A, c = 10.501 (2) A, a = 109.39(2)°, a = 94.41(2)°, a = 100.04(1) °,Ⅴ = 570.6 (2) A3, Z = 2, Dc = 1.305 Mg/m3, i (Mo Ka)= 0.266 mm-1, F(000) = 236. The final R andu R are 0.0358 and 0.0919 for 1823 observed reflections [Ⅰ>2o(Ⅰ)].Fig. 1 shows the molecular crystal structure indicating that the carbonyl and thiocarbonyl moieties are pointing in

  4. Enrofloxacinium oxalate.

    Science.gov (United States)

    Yamuna, Thammarse S; Kaur, Manpreet; Anderson, Brian J; Jasinski, Jerry P; Yathirajan, H S

    2014-02-01

    The title salt, 2C19H23FN3O3 (+)·C2O4 (2-) {systematic name: bis-[4-(3-carb-oxy-1-cyclo-propyl-6-fluoro-4-oxo-1,4-di-hydro-quino-lin-7-yl)-1-ethyl-piperazin-1-ium] oxalate}, crystallizes with two independent monocations (A and B) and an oxalate dianion (C) in the asymmetric unit. The piperazinium ring in both the cations adopts a slightly disordered chair conformation. The dihedral angles between the mean planes of the cyclo-propyl ring and the 10-membered quinoline ring are 50.6 (5)° (A) and 62.2 (5)° (B). In each of the cations, a single O-H⋯O intra-molecular hydrogen bond is observed. In the crystal, the oxalate anions inter-act with the cations through N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions, forming R 2 (2)(8) graph-set ring motifs. Weak C-H⋯F inter-actions along with further C-H⋯O inter-actions are observed between the cations, forming zigzag chains along [001]. In addition, π-π stacking inter-actions are observed with centroid-centroid distances of 3.5089 (13), 3.5583 (13), 3.7900 (13) and 3.7991 (13) Å.

  5. Synthesis, biological evaluation and molecular docking of N-phenyl thiosemicarbazones as urease inhibitors.

    Science.gov (United States)

    Hameed, Abdul; Khan, Khalid Mohammed; Zehra, Syeda Tazeen; Ahmed, Ramasa; Shafiq, Zahid; Bakht, Syeda Mahwish; Yaqub, Muhammad; Hussain, Mazhar; de la Vega de León, Antonio; Furtmann, Norbert; Bajorath, Jürgen; Shad, Hazoor Ahmad; Tahir, Muhammad Nawaz; Iqbal, Jamshed

    2015-08-01

    Urease is an important enzyme which breaks urea into ammonia and carbon dioxide during metabolic processes. However, an elevated activity of urease causes various complications of clinical importance. The inhibition of urease activity with small molecules as inhibitors is an effective strategy for therapeutic intervention. Herein, we have synthesized a series of 19 benzofurane linked N-phenyl semithiocarbazones (3a-3s). All the compounds were screened for enzyme inhibitor activity against Jack bean urease. The synthesized N-phenyl thiosemicarbazones had varying activity levels with IC50 values between 0.077 ± 0.001 and 24.04 ± 0.14 μM compared to standard inhibitor, thiourea (IC50 = 21 ± 0.11 μM). The activities of these compounds may be due to their close resemblance of thiourea. A docking study with Jack bean urease (PDB ID: 4H9M) revealed possible binding modes of N-phenyl thiosemicarbazones.

  6. Synthesis and characterization of 2-hydroxy-N-methyl-N-phenyl-acetamide

    Institute of Scientific and Technical Information of China (English)

    周忠诚; 舒万艮

    2002-01-01

    2-hydroxy-N-methyl-N-phenyl-acetamide was synthesized by using N-methylaniline, chloracetyl chloride, anhydrous sodium acetate and methanol through the acetylation, esterfication and ester interchange steps. The acetylation of N-methylaniline with chloracetyl chloride, catalyzed by triethylamide with mole ratio n(C6H5NHCH3)∶n(ClCH2C(O)Cl)∶n(N(C2H5)3)=1∶1.05∶1, the yield of 2-chloro-N-methyl-N-phenyl- acetamide(Ⅰ) was 93.8%; Then the esterification of Ⅰ with anhydrous sodium acetate in the presence of phase transfer catalyst tetrabutyl ammonia bromide gave 97.3% yield of 2-acetoxyl-N-methyl-N-phenyl-acetamide (Ⅱ); The ester interchange of with methanol catalyzed by potassium hydroxide gave 2-hydroxy-N-methyl-N-phenyl-acetamide (Ⅲ) in 96.4% yield. And the total yield was 88.0%. IR and MS spectroscopy of products were analyzed and their characteristic peaks were assigned. Combining the results of elemental analysis, the molecular structure of Ⅰ, Ⅱ and Ⅲ was identified.

  7. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Jun Jie Gao; Hui Quan Li; Yi Zhang

    2007-01-01

    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  8. Oxalate catabolism in Arabidopsis

    Science.gov (United States)

    Oxalic acid is found in most plant species and can serve beneficial roles that protect the plant from a variety of environmental stresses. Excessive amounts of oxalate, however, can be detrimental to plant health. Thus, careful coordination of oxalate metabolism is needed. Despite the important impa...

  9. Structural characterization of some N-phenyl-4-oxo-4H-2-chromone carboxamides.

    Science.gov (United States)

    Gomes, Ligia Rebelo; Low, John Nicolson; Cagide, Fernando; Gaspar, Alexandra; Reis, Joana; Borges, Fernanda

    2013-06-01

    N-phenyl-4-oxo-4H-2-chromone carboxamides were found to be inactive as MAO inhibitors in contrast with their N-phenyl-4-oxo-4H-3-chromone carboxamide isomers. In order to obtain a close insight into the docking mechanism for this family of compounds, the molecular and supramolecular structures of nine N-phenyl-4-oxo-4H-2-chromone carboxamides were determined. It was found that, in most of the secondary structures, the N(amido) and the O(carboxyl) of the carboxamide residue participate in strong intramolecular interactions, with the O atom of the chromene ring and with the H(ortho)-C (phenyl), respectively. When the phenyl ring had accessible acceptors as substituents a third intramolecular hydrogen bond was also observed. As a consequence, rotations of the chromone and phenyl rings around the N-C(alpha) and C(alpha')-C=O are constrained and the compounds were found to be more planar than would otherwise be expected. The deviation from planarity of the whole molecule can be quantified by the dihedral angles between mean planes of the aromatic rings and it was found that they were mainly affected by the degree of torsion of the phenyl ring with respect to the amide residue. The molecular conformations assumed by the secondary amides clearly contrast with that of a related tertiary amide that was also determined in this study. The unavailability of the N in this compound as a donor strongly influences the molecular isomerism and conformation. This analysis demonstrates that the molecules can be classified into four groups depending on the types of interactions formed as described above. If the secondary N(amido) of the carboximide is involved in two intramolecular interactions then this atom does not form any intermolecular contacts. In all other cases it does and the supramolecular structure formed is in most cases supplemented by weak C-H···O interactions.

  10. Bioconversion of 6-(N-methyl-N-phenyl)aminomethyl androstane steroids by Nocardioides simplex.

    Science.gov (United States)

    Sukhodolskaya, Galina; Fokina, Victoria; Shutov, Andrei; Nikolayeva, Vera; Savinova, Tatiana; Grishin, Yuri; Kazantsev, Alexey; Lukashev, Nikolay; Donova, Marina

    2017-02-01

    The newly synthesized (α/β)-diastereomers of 6-(N-methyl-N-phenyl)aminomethylandrost-4-ene-3,17-dione (5) and 6-(N-methyl-N-phenyl)aminomethylandrost-4-en-17β-ol-3-one (6) were firstly investigated as substrates for the whole cells of Nocardioides simplex VKM Ac-2033D in comparison with their unsubstituted analogs, - androst-4-ene-3,17-dione (1) and androst-4-en-17β-ol-3-one (2). 1(2)-Dehydroderivatives were identified as the major bioconversion products from all the substrates tested. When using the mixtures of (α/β)-stereoisomers of 5 and 6 as the substrates, only β-stereoisomers of the corresponding 1,4-diene-steroids were formed. Along with 1(2)-dehydrogenation, N. simplex VKM Ac-2033D promoted oxidation of the hydroxyl group at C-17 position of 6: both 6(α) and 6(β) were transformed to the corresponding 17-keto derivatives. No steroid core destruction was observed during the conversion of the 6-substituted androstanes 5 and 6, while it was significant when 1 or 2 was used as the substrate. The results suggested high potentials of N. simplex VKM Ac-2033D for the generation of novel 1(2)-dehydroanalogs.

  11. Synthesis and antiproliferative activity of 3-amino-N-phenyl-1H-indazole-1-carboxamides.

    Science.gov (United States)

    Raffa, Demetrio; Maggio, Benedetta; Cascioferro, Stella; Raimondi, Maria Valeria; Schillaci, Domenico; Gallo, Giorgio; Daidone, Giuseppe; Plescia, Salvatore; Meneghetti, Fiorella; Bombieri, Gabriella; Di Cristina, Antonietta; Pipitone, Rosaria M; Grimaudo, Stefania; Tolomeo, Manlio

    2009-01-01

    A series of new 3-amino-N-phenyl-1H-indazole-1-carboxamides 10 have been prepared from commercially available phenyl isocyanate precursors 8 and 3-aminoindazole 9. Some of the synthesized compounds were evaluated for their in vitro antineoplastic activity against 60 human cell lines derived from seven clinically isolated cancer types (lung, colon, melanoma, renal, ovarian, brain, and leukemia) according to the NCI standard protocol. The test results indicated that 3-amino-1H-indazole-1-carboxamides 10 were endowed with an interesting antiproliferative activity. The most active compounds of this series, 10d,e, were able to inhibit cell growth of many neoplastic cell lines at concentrations lower than 1 microM (0.0153 microM in SR leukemia) causing a block in G0-G1 phase of cell cycle. Analysis of pRb expression showed that these two compounds increased the ratio between underphosphorylated pRb and total pRb. The X-ray structure of 10w, confirmed the 3-amino-N-phenyl-1H-indazole-1-carboxamide structure of compounds 10.

  12. Computational Studies on 2(2-Hydroxyphenyl-N-phenyl Nitrone, Spectroscopic Investigation.

    Directory of Open Access Journals (Sweden)

    R. Kumutha

    2014-12-01

    Full Text Available The title compound 2(2-Hydroxyphenyl-N-phenyl Nitrone (2HPNPN was synthesized and characterized by FT-IR, FT-Raman spectral analysis. The molecular geometry, harmonic vibrational frequencies and bonding features of the title compound in the ground state are computed at three parameter hybrid functional Lee-Yang-parr/6-311++G(d,p levels of theory. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA following the scaled quantum mechanical force field methodology (SQMF. Finally, the calculations are applied to simulated FT-IR and FT-Raman spectra of the title compound which show good agreement with observed spectra.

  13. SBR COMPOSITES REINFORCED WITH N-ISOPROPYL-N'-PHENYL-P-PHENYLENEDIAMINE-MODIFIED CLAY

    Institute of Scientific and Technical Information of China (English)

    Habibollah Baharvand; Ghasem Naderi; Sedigheh Soltani

    2011-01-01

    SBR compounds including the N-isopropyl-N'-phenyl-p-phenylenediamine-modified clay (organoclay) were prepared. Effects of modified clay and antioxidant (IPPD) contents on mechanical and rheological properties of SBR composites were studied. FTIR results confirmed that the clay was chemically modified by IPPD and changed into an organoclay. X-ray diffraction (XRD) results confirmed the increase in interlayer distance of the clay due to the insertion of IPPD. Rheological and cure characteristics of SBR compounds were determined using RPA (Rubber Process Analyzer) and rheometer. Scorch time and cure time of SBR compounds decreased with introduction of the organoclay. Mechanical properties and heat aging resistance of the SBR composites were improved significantly by incorporation of the organoclay.

  14. Luminescent properties and photostability of thin films of N,N'-phenyl-substituted biphenyls

    Science.gov (United States)

    Chaplanova, Zh. D.; Mikhailovskii, Yu. K.; Agabekov, V. E.; Galinovskii, N. A.; Gracheva, E. A.

    2012-11-01

    We have studied the luminescent properties and morphology of thin films, formed by deposition from solutions (wet) and thermal vacuum deposition (TVD), of 4,4'- bis[(E)-2-[4-(diphenylamino)phenyl]ethenyl]-1,1'-biphenyl (PAB-1) and its 2-oxyhexyl derivative (PAB-2). We have established that the presence of an oxyhexyl side substituent in the structure of N,N'-phenyl-substituted biphenyl promotes quenching of the photoluminescence of the TVD film based on it when stored in air. We show that introducing PAB-2 into a polymer matrix (polymethylmethacrylate, polystyrene, polycyclohexadiene) significantly improves the stability of such composite films when exposed to UV light and to oxygen in the air. We use electron diffraction and atomic force microscopy to establish that these films have an amorphous structure that remains resistant to degradation during photooxidative aging.

  15. Speciation study on the interaction of some divalent transition metal ions with succinic acid dihydrazide in aqueous medium.

    Science.gov (United States)

    Satyanarayana, Atreyapurapu; Kenie, Dunkana Negussa; Shyamala, Pulipaka

    2013-01-01

    The interaction of succinic acid dihydrazide with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) was investigated in aqueous medium at 303K and ionic strength of 0.1 mol dm-3. The speciation and stability constants of the metal complexes formed were determined by pH-metric method. Mononuclear and homo binuclear species in different protonation and deprotonation states were identified, the corresponding formation constants calculated using MINIQUAD-75 computer program, and species distribution diagrams produced using the HYSS computer program. Selection of the best-fit chemical models was based on statistical parameters.

  16. Conformational isomerization of N-(naphthalen-1-yl)-N-(phenyl(quinolin-3-yl)methyl)amide derivatives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A series of N-(naphthalen-1-yl)-N-(phenyl(quinolin-3-yl)methyl)amide derivatives were designed and synthesized as anti-Mycobacterium tuberculosis drugs. NMR spectra showed that two conformational isomers of these compounds exist in solution,which is not due to cis-trans isomerization of amide bond. We proposed that the spatial interactions between three large aromatic groups caused the conformational isomerization,which was supported by molecular modeling and X-ray diffraction.

  17. Synthesis of substituted 3-amino-N-phenyl-1H-indazole-1-carboxamides endowed with antiproliferative activity.

    Science.gov (United States)

    Maggio, Benedetta; Raimondi, Maria Valeria; Raffa, Demetrio; Plescia, Fabiana; Cascioferro, Stella; Plescia, Salvatore; Tolomeo, Manlio; Di Cristina, Antonietta; Pipitone, Rosaria Maria; Grimaudo, Stefania; Daidone, Giuseppe

    2011-01-01

    Several new N-phenyl-1H-indazole-1-carboxamides 1c-h and 4l,m were prepared by reacting phenyl isocyanate derivatives 3a,b with 3-amino-1H-indazole derivatives 2c,e,g or 1H-indazole 2l respectively. Chemical transformations of compounds 1a,b and 1g,h gave 3-acetamido-N-phenyl-1H-indazole-1-carboxamide derivatives 5a,b, and 3,5-diamino-N-phenyl-1H-indazole-1-carboxamide derivatives 4i,j respectively. Finally, 3,5-diacetamido-N-phenyl-1H-indazole-1-carboxamide derivatives 6a,b were prepared by acetylation of 4i,j. Some of synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell lines panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). Compound 1c, the most active of the series, was able to inhibit cell growth showing GI(50) values in the 0.041-33.6 μM range, mean GI(50) 1.90 μM, being very effective against colon and melanoma cell lines. Cell cycle analysis in K562 cells showed that 1c causes a marked increase of cells in G0-G1 phase. Moreover, it increases the ratio between hypophosphorylated pRb and total pRb.

  18. Discovery and Characterization of the N-phenyl-N 0 -Naphthylurea Class of p38 Kinase Inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Cirillo, P.; Hickey, E; Moss, N; Breitfelder, S; Betageri, R; Fadra, T; Gaenzler, F; Gilmore, T; Xiong, Z; et al.

    2009-01-01

    An effort aimed at exploring structural diversity in the N-pyrazole-N{prime}-naphthylurea class of p38 kinase inhibitors led to the synthesis and characterization of N-phenyl-N{prime}-naphthylureas. Examples of these compounds displayed excellent inhibition of TNF-{alpha} production in vitro, as well as efficacy in a mouse model of lipopolysaccharide induced endotoxemia. In addition, perspective is provided on the role of a sulfonamide functionality in defining inhibitor potency.

  19. Uranyl Oxalate Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Leturcq, G.; Costenoble, S.; Grandjean, S. [CEA Marcoule DEN/DRCP/SCPS/LCA - BP17171 - 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    The solubility of uranyl oxalate was determined at ambient temperature by precipitation in oxalic-nitric solutions, using an initial uranyl concentration of 0.1 mol/L. Oxalic concentration varied from 0.075 to 0.3 mol/L while nitric concentration ranged between 0.75 and 3 mol/L. Dissolution tests, using complementary oxalic-nitric media, were carried out for 550 hours in order to study the kinetic to reach thermodynamic equilibrium. Similar solubility values were reached by dissolution and precipitation. Using the results, it was possible to draw the solubility surface versus oxalic and nitric concentrations and to determine both the apparent solubility constant of UO{sub 2}C{sub 2}O{sub 4}, 3H{sub 2}O (Ks) and the apparent formation constant of the first uranyl-oxalate complex UO{sub 2}C{sub 2}O{sub 4} (log {beta}1), for ionic strengths varying between 1 and 3 mol/L. Ks and log {beta}1 values were found to vary from 1.9 10{sup -8} to 9.2 10{sup -9} and from 5.95 to 6.06, respectively, when ionic strength varied from 1 to 3 mol/L. A second model may fit our data obtained at an ionic strength of 3 mol/L suggesting as reported by Moskvin et al. (1959) that no complexes are formed for [H{sup +}] at 3 M. The Ks value would then be 1.3 10{sup -8}. (authors)

  20. Influence of end groups in hyperbranched polyesters used as modifiers in the characteristics of epoxy thermosets cured by adipic dihydrazide

    Directory of Open Access Journals (Sweden)

    A. Serra

    2013-07-01

    Full Text Available Mixtures of diglycidylether of bisphenol A (DGEBA resin and different ratios of aliphatic-aromatic hyperbranched polyester (HBP were cured by a latent curing agent, adipic dihydrazide (AH. The HBPs prepared have hydroxyl groups or 10-undecenoyl or allyl groups as chain ends. The curing mixtures were investigated by differential scanning calorimetry (DSC to study the curing process and to evaluate the kinetic parameters of the different formulations. These studies suggest that HBPs decrease the curing rate of epoxy/AH in the case of vinyl terminated HPB, whereas OH terminated HBP accelerates the first stages and delays the lasts. The thermosets obtained showed an improvement in microhardness and impact strength without any reduction of the Tg and thermal parameters. Microparticle phase separation was observed with the undecenoyl HBP derivatives or when a 10% of allyl HBP derivative was in the formulation.

  1. Ultrasound-induced controllable morphology and growth dimension in a dihydrazide-based self-assembly system.

    Science.gov (United States)

    Zhang, Yan; Ding, Hao; Wu, Yangfang; Zhang, Chunxue; Bai, Binglian; Wang, Haitao; Li, Min

    2014-11-28

    We have demonstrated ultrasound-induced organogels based on twin-tapered dihydrazide derivatives, oxalyl acid N,N-di(3,4,5-trialkoxybenzoyl)hydrazide (FH-Tn). Ultrasound irradiation has been proved to influence gel properties at micro-levels. Different self-assembled structures from entangled fibers to tube-like structures and nanoparticles can be easily manipulated by tuning irradiation time and water bath temperature. FT-IR spectra exhibit weakened hydrogen bonding interactions, and XRD studies showed different packing modes before and after sonication. In addition, ultrasound can have effects on gel properties at macro-levels. Gels obtained from ultrasound treatment possess different wetting properties, relatively worse rheological properties and thermo-stability. Kinetic studies based on dynamic fluorescence spectra, rheological studies and theoretical calculations suggest that molecular aggregation mode differed from one-dimension to two-dimension for the gel after sonication.

  2. Acid–base equilibria of the Zn(II and Fe(III complexes with condensation products of 2-acetylpyridine and the dihydrazide of oxalic and malonic acid

    Directory of Open Access Journals (Sweden)

    DUŠAN SLADIĆ

    2009-03-01

    Full Text Available Acid–base equilibria of Zn(II and Fe(III complexes with N',N'2-bis[(1E-1-(2-pyridylethylidene]ethanedihydrazide (ligand L1 and N',N'2-bis[(1E-1-(2-pyridylethylidene]propanedihydrazide (ligand L2, i.e., [Fe(L1Cl2(H2O], [Fe(L2Cl(H2O]2+, [Zn(L1(H2O3]+ and [Zn(L2(H2O2]2+, which expressed cytotoxic activity, were investigated in aqueous media. The equilibrium constants were determined potentiometrically at 25 °C at a constant ionic strength of 0.10 mol/dm3 (Na2SO4. The results showed that at pH < 8 both the Fe(III complexes studied here have three, while [Zn(L1(H2O3]+ and [Zn(L2(H2O2]2+ have one and two titratable protons, respectively. Based on the obtained values for the equilibrium constants, protonation schemes of the examined complexes are proposed.

  3. Literature review for oxalate oxidation processes and plutonium oxalate solubility

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-01

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign.

  4. Discovery of novel N-phenyl 1,4-dihydropyridines with a dual mode of antimycobacterial activity.

    Science.gov (United States)

    Lentz, Fabian; Hemmer, Marc; Reiling, Norbert; Hilgeroth, Andreas

    2016-12-15

    There is an urgent need for novel drugs for the treatment of tuberculosis (TB) due to the increasing prevalence of antibiotic resistance among Mycobacterium tuberculosis (Mtb) strains against first-line and second-line therapeutics. We developed novel N-phenyl 1,4-dihydropyridines as potential antituberculotic agents. The observed activity depends on the substitution patterns of the aromatic residues. N-unsubstituted 1,4-dihydropyridines are known inhibitors of the cancer-relevant transmembrane efflux pump ABCB1. Based on the similarity of ABCB1 amino acids sequences relevant to 1,4-dihydropyridine binding and the MTb efflux pump Rv0194, we determined ABCB1-inhibitory properties of our compounds in a cell line model. We identified one compound, which substantially increased the activity of two antituberculotic drugs which are substrates of ABCB1. The data indicate that our N-phenyl 1,4-dihydropyridines represent a novel compound class which improves the efficacy of anti-TB drugs by interfering with transmembrane efflux pumps in Mtb. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.

    2012-02-03

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

  6. Tetraphenylphosphonium hydrogen oxalate

    Directory of Open Access Journals (Sweden)

    Philip A. W. Dean

    2008-01-01

    Full Text Available In the title compound, C24H20P+·C2HO4−, two symmetry-independent ion pairs are present. The cations aggregate into puckered sheets via zigzag infinite chains of sixfold phenyl embraces and parallel fourfold phenyl embraces, while the anions form hydrogen-bonded chains between the sheets of cations. In the two independent oxalate anions, the angles between the normals to the two least-squares carboxylate COO planes are unusually large, viz. 72.5 (1 and 82.1 (1°.

  7. Reactivity of N-Phenyl-1-Aza-2-Cyano-1,3-Butadienes in the Diels-Alder Reaction.

    Science.gov (United States)

    Sisti, Nicholas J.; Motorina, Irina A.; Tran Huu Dau, Marie-Elise; Riche, Claude; Fowler, Frank W.; Grierson, David S.

    1996-05-31

    It is found that N-phenyl-2-cyano-1-azadiene 4, prepared via a two-step, one-pot, sequence from acrylanilide, undergoes efficient [4 + 2] cycloaddition with a complete range of electron rich, electron poor, and neutral dienophiles under remarkably mild thermal conditions (90-120 degrees C for 20-48 h). Regiospecific formation of the alpha-cycloadduct wherein the dienophile substituent is alpha to nitrogen is observed for vinyl ethers and styrene, whereas the Diels-Alder reactions with methyl acrylate and methyl vinyl ketone (MVK) produce alpha/beta mixtures in which the alpha-cycloadduct is the major regioisomer (approximately 4-5:1). An essentially identical reaction pattern was observed in the Diels-Alder reaction of N-(p-methoxyphenyl)-2-cyano-1-azadiene 18 and the 4-methyl-substituted azadiene 27. For compound 19 derived from cycloaddition of 18 with ethyl vinyl ether, facile conversion to the dihydropyridine 21 through loss of EtOH on brief acid treatment was also noted. The 2,4-cis-disubstitution pattern confirmed by X-ray diffraction for the major cycloadduct 29 isolated from the reaction of 27 with styrene provides evidence for the endo mode of cycloaddition in the Diels-Alder reaction of N-phenyl(aryl)-2-cyano-1-azadienes. Calculation of the frontier orbital energies and coefficients, as well as the transition state geometries for the [4 + 2] cycloaddition of N-phenyl-2-cyano-1-azadiene 4 with methyl vinyl ether, styrene, and MVK were carried out at the RHF AM1 level (MOPAC, Version 5.0). The FMO treatment indicates that the reaction of 4 with methyl vinyl ether occurs under LUMO(diene) control, whereas in contrast, the corresponding cycloaddition with MVK occurs preferably under HOMO(diene) control. A high degree of asynchronicity is observed in the calculated transition states for reaction of 4 with the three representative dienophiles. In all cases the transition states leading to the alpha-cycloadducts are lower in energy than those giving the beta

  8. Synthesis, Structure and Biological Activities of 2-(4-Methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide

    Institute of Scientific and Technical Information of China (English)

    LIU Fa-qian; QIN Yong-qi; LI Wei-hua; YANG Shuang-hua; LU Lu-de; YANG Xu-jie; WANG Xin; HOU Bao-rong

    2005-01-01

    The title compound, 2-(methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide was synthesized by several reactions from 4-methoxyacetophenone, triazole and phenyl isothiocyanate. The structure was identified by elemental analysis, 1H NMR, MS and IR. The single crystal structure of 2-(methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide was determined with X-ray diffraction. The preliminary bioassays show that the title compound exhibits weak antifungal activities and plant-growth regulatory activity.

  9. In vivo metabolism of N-phenyl-N'-(3,5-dimethylpyrazole-4-yl) thiourea in rats.

    Science.gov (United States)

    Kaymakcioğlu, Bedia Koçyiğit; Rollas, Sevim; Kartal-Aricioğlu, Feyza

    2003-01-01

    Thiourea derivatives have been shown to posses several biological activities. Therefore a series of N-substituted -N'-(3,5-di/1,3,5trimethylpyrazole-4-yl)thioureas were synthesized and the antitubercular and anticonvulsant activities were studied. Among the new compounds, N-phenyl-N'-(3,5-dimethylpyrazole4-yl)thiourea (S) was demonstrated to have remarkable anticonvulsant activity. In this study, S was selected as a model compound and the in vivo metabolic pathway in rats was investigated. The substrate was given intraperitoneally (50 mg/kg) and blood samples were collected at 0, 1, 2, 4, 8, 12, 24 and 48 h. The substrate and its potential metabolites were separated using HPLC on reverse phase system. The substrate was detected at all times with small quantity of metabolites.

  10. Influence of Solvent on Reaction Path to Synthesis of Methyl N-Phenyl Carbamate from Aniline, CO2 and Methanol

    Institute of Scientific and Technical Information of China (English)

    安华良; 张丽丽; 苑保国; 赵新强; 王延吉

    2014-01-01

    Methyl N-phenyl carbamate (MPC), an important organic chemical, can be synthesized from aniline, CO2 and methanol. Catalyst Cu-Fe/ZrO2-SiO2 was first prepared and its catalytic performance for MPC synthesis was evaluated. Then the influence of solvent on the reaction path of MPC synthesis was investigated. It is found that the reaction intermediate is different with acetonitrile or methanol as a solvent. With acetonitrile as a solvent, the synthesis of MPC follows the reaction path with diphenyl urea as the intermediate, while with methanol as a solvent the reaction occurs via the reaction path with dimethyl carbonate as the intermediate. The catalytic mecha-nism of cooperative catalysis comprising metal sites, Lewis acid sites and Lewis base sites is proposed according to different reaction intermediates.

  11. Gelation behaviour of a bent-core dihydrazide derivative: effect of incubation temperature in chloroform and toluene.

    Science.gov (United States)

    Zhang, Chunxue; Zhang, Tianren; Ji, Nan; Zhang, Yan; Bai, Binglian; Wang, Haitao; Li, Min

    2016-02-01

    In this work, a new kind of gelator, 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide]phenylene (BP8-C), containing two dihydrazide units as the rigid bent-core, has been synthesized and investigated. It was demonstrated that BP8-C is an efficient gelator which can gel various organic solvents, such as ethanol, benzene, toluene, chloroform, etc. Both an opaque gel (O-gel) and a transparent gel (T-gel), which is more stable, were obtained with BP8-C in chloroform at different incubation temperatures. Kinetic data based on fluorescence spectra revealed that the T-gels showed a larger Avrami parameter (n = 1.44 at 20 °C) than that of the O-gels (n = 1.21 for gelation at temperatures below 0 °C). While BP8-C did form the opaque gel in toluene, gelation took longer at lower incubation temperatures and even precipitated out below 0 °C. The kinetic Avrami analysis on sols of BP8-C with different concentrations shows a two-phrase mechanism, i.e. the n values are between 0.88 and 1.74 followed by 1.69 and 3.01 throughout the temperature range of 5 °C and 35 °C for 5.34 mg mL(-1) BP8-C in toluene, indicating that the fibers formed first and then bundled to produce compact networks. We propose that supersaturation governs the formation of gel in chloroform and that the diffusion process denominates gelation in toluene. XRD and FT-IR measurements confirmed that the xerogels prepared at different temperatures in different solvents exhibited a Col(h) structure and that there are three molecules in one columnar slice. Our results indicate that the gelation process, morphology of the gels and thus the final properties of the gels depend strongly on the preparation conditions such as temperature, solvent, concentration, etc.

  12. Analytical Study of Oxalates Coprecipitation

    Directory of Open Access Journals (Sweden)

    Liana MARTA

    2003-03-01

    Full Text Available The paper deals with the establishing of the oxalates coprecipitation conditions in view of the synthesis of superconducting systems. A systematic analytical study of the oxalates precipitation conditions has been performed, for obtaining superconducting materials, in the Bi Sr-Ca-Cu-O system. For this purpose, the formulae of the precipitates solubility as a function of pH and oxalate excess were established. The possible formation of hydroxo-complexes and soluble oxalato-complexes was taken into account. A BASIC program was used for tracing the precipitation curves. The curves of the solubility versus pH for different oxalate excess have plotted for the four oxalates, using a logaritmic scale. The optimal conditions for the quantitative oxalate coprecipitation have been deduced from the diagrams. The theoretical curves were confirmed by experimental results. From the precursors obtained by this method, the BSCCO superconducting phases were obtained by an appropriate thermal treatment. The formation of the superconducting phases was identified by X-ray diffraction analysis.

  13. Aluminum-activated Oxalate Secretion does not Associate with Internal Content among Some Oxalate Accumulators

    Institute of Scientific and Technical Information of China (English)

    Jian Li Yang; Lei Zhang; Shao Jian Zheng

    2008-01-01

    Although aluminum (AI)-activated secretion of oxalate has been considered to be an Important AI-exclusion mechanism,whether it is a general response in oxalate accumulators and related to oxalate content in roots are still not clear.Here,we examined the oxalate secretion and oxalate content in some oxalate accumulators,and investigated the role of oxalate secretion in AI resistance.When oxalate content in amaranth roots was decreased by about 50% with the increased ratio of NH4+-N to NO3——N in nutrient solution,the amount of AI-activated oxalate secretion still remained constant.There was no relationship between the content of the water soluble oxalate in four species of oxalate accumulators and the amount of the AI-activated oxalate secretion in roots.Furthermore,oxalate secretion is poorly associated with AI resistance among these species.Based on the above results,we concluded that although all of the oxalate accumulators tested could secrete oxalate rapidly,the density of anion channels in plasma membrane may play a more important role in AI-activated oxalate secretion.Key words: aluminum toxicity; Amaranthus; anion channel; oxalate accumulator; oxalate secretion.

  14. Kinetics and mechanism of the chain reaction between N-phenyl-1,4-benzoquinone monoimine and thiophenol

    Science.gov (United States)

    Varlamov, V. T.; Gadomsky, S. Ya.

    2017-05-01

    The kinetics of the reaction between N-phenyl-1,4-benzoquinone monoimine (quinone monoimine) and thiophenol is studied in chlorobenzene at 343 K. The reaction has the same mechanism proposed earlier for a similar reaction involving N,N'-diphenyl-1,4-benzoquinone diimine (quinone diimine). This mechanism has two paths: chain and nonchain. An important difference between the kinetics of the two reactions is the apparent reversible nature of the chain reaction in the quinone monoimine + thiophenol system. This nature reveals itself when the concentrations of thiophenol are comparable to or slightly higher than the concentrations of quinone imine. In light of this, kinetic research is conducted under conditions where the concentrations of thiophenol are significantly higher than those of quinone monoimine, allowing us to simplify the kinetic features and obtain interpretable data. The rate constants of the reaction's elementary steps are estimated and found to be three to five times lower for the reaction involving quinone monoamine than for the one involving quinone diimine. Both reactions have relatively short chains whose lengths do not exceed several tens of units.

  15. Poly(vinyl chloride) blend with biodegradable cellulose acetate in presence of N-(phenyl amino) maleimides.

    Science.gov (United States)

    Abdel-Naby, Abir S; Al-Ghamdi, Azza A

    2014-09-01

    Wider plastic applications of poly(vinyl chloride) (PVC) has raised serious problem to the environment. Since (PVC) waste products resist biodegradation and persist in the environment for longer time. The object of this study is to blend (PVC) with biodegradable cellulose acetate to thermally support the polymer during the molding process as well as to enhance the biodegradability of (PVC) waste products. Blending of poly(vinyl chloride) and cellulose acetate (CA) in presence of N-(phenyl amino) maleimides (R-PhAM) where (R=H, 4-NO2) led to improvement in the thermal stability of the blend film at high temperatures as shown from the high values of initial decomposition temperature (To) determined from their thermogravimetry (TG) curves. Also, blending (PVC) with (CA) led to improvement in the mechanical properties of the blend films as compared to (PVC). The crystalline regions of cellulose acetate enhanced the elasticity of the blend films as shown from their high Young's modulus values.

  16. Synthesis, spectroscopic characterization and X-ray structure of novel 7-methoxy-4-oxo-N-phenyl-4H-chromene-2-carboxamides

    Science.gov (United States)

    Reis, Joana; Gaspar, Alexandra; Borges, Fernanda; Rebelo Gomes, Ligia; Low, John Nicolson

    2014-01-01

    The chromone scaffold has been found to be an important tool in the drug discovery process through its relevant pharmacological activities. Chromone carboxamide derivatives synthesized within our group have shown noteworthy results as inhibitors of monoamino oxidase-B and as ligands for adesonine receptors. Specifically, chromone-2-carboxamide has been shown to be a privileged structure for the development of selective A3 adenosine receptor ligands. In this work two novel substituted 4-oxo-N-phenyl-4H-chromene-2-carboxamides have been synthesized and a complete structural characterization was performed using Fourier Transform Infrared Spectroscopy, one-dimensional and two-dimensional Nuclear Magnetic Resonance techniques and Mass Spectroscopy. Finally, the molecular and supramolecular structures were determined by X-ray analysis. The X-ray crystallographic analysis describes in detail the molecular conformation and supramolecular structure of a hemihydrate of 7-methoxy-4-oxo-N-phenyl-4H-chromene-2-carboxamide.

  17. Synthesis of New N-phenyl Fulleroisoxazoline in the Presence of Fe3O4@SiO2 Nanoparticles as an Efficient Magnetically Recoverable and Reusable Catalyst

    Directory of Open Access Journals (Sweden)

    J. Safaei-Ghomi

    2014-07-01

    Full Text Available In this research an effective and appropriate method has been developed for one-pot synthesis of new N-phenyl fulleroisoxazoline using Fe3O4@SiO2 nanoparticles as a green magnetically recyclable catalyst. The prepared catalytic samples were characterized by XRD, SEM, FT-IR and VSM. The products have been characterized by physical and spectroscopic data such as IR, 1H NMR, 13C NMR, and MS analyses.

  18. Clinical investigation on gastric oxalate absorption

    Institute of Scientific and Technical Information of China (English)

    陈志强; 叶章群; 曾令启; 杨为民

    2003-01-01

    Objective To study the stomach role in exogenous oxalate absorption.Methods The kinetic variation of urinary oxalate excretion (mg/min) in 10 healthy adults and 8 patients who underwent total gastrectomy was investigated before and after an oral spinach oxalate load. The bioavailability of the oxalate load in the healthy adults was calculated and compared with that in the patients.Results The oxalate content in the oral spinach load was 2567-2670 mg. The urinary oxalate excretion (mg/min) in the 10 healthy adults increased significantly 20 minutes after loading (this increase was compared against their basic oxalate excretion level of 0.0331±0.0203). Further observations after loading include: a first peak of oxalate excretion 40 minutes after loading; an oxalate excretion level double that of the basic level after 60 minutes (0.0732±0.0294) and a second peak appearing at 3 hours (P<0.01). A "first peak" (0.063%±0.062%) was not in any of the patients who underwent a total gastrectomy. Furthermore, a bioavailability of oxalate, which was 50% lower than that in the healthy subjects, appeared 60 minutes after loading (0.098%±0.071%, P<0.01). Conclusions The stomach is a powerful oxalate absorption organ under normal physiological conditions. Further investigation on the relationship between stomach dysfunction and urinary calcium oxalate formation is needed.

  19. Variation in oxalate and oxalate decarboxylase production by six species of brown and white rot fungi

    DEFF Research Database (Denmark)

    Hastrup, Anne Christine Steenkjær; Oliver, Jason; Howell, Caitlin;

    cell lumen where it quickly dissociates into hydrogen ions and oxalate, resulting in a pH decrease of the environment, and oxalate-cation complexes. Generally, brown rot fungi accumulate larger quantities of oxalic acid in the wood than white rot fungi. The amount of oxalic acid has been shown to vary...... of formic acid and CO2 (Makela et al., 2002). So far only a few species of brown rot fungi have been shown to accumulate this enzyme (Micales, 1995, Howell and Jellison, 2006).   The purpose of this study was to investigate the variation in the levels of soluble oxalate and total oxalate, in correlation...

  20. Influence of N-phenyl-2-naphthylamine on the Activity of Adenylate Cyclase Signaling System and the Virulence of Clavibacter michiganensis subsp. sepedonicus

    Directory of Open Access Journals (Sweden)

    A.M. Goncharova

    2016-11-01

    Full Text Available The effect of N-phenyl-2-naphthylamine was obtained from exudates of pea root on growth, virulence and signaling-specific of potato phytopathogen Clavibacter michiganensis subsp. sepedonicus. It is shown that the compound in a physiological concentration of the peas 9 mkM had no effect on C. michiganensis subsp. sepedonicus, but when exposed to N-FNA in a concentration of 45 mkM was observed reduction in growth of planktonic culture C. michiganensis subsp. sepedonicus, as well as changes in the activity of adenylyl cyclase signaling system components in this phytopathogen.

  1. In vivo oxalate degradation by liposome encapsulated oxalate oxidase in rat model of hyperoxaluria

    Directory of Open Access Journals (Sweden)

    Tulika Dahiya

    2013-01-01

    Interpretation & conclusions: EMA-oxalate oxidase encapsulated liposome caused oxalate degradation in experimental hyperoxaluria indicating that the enzyme could be used as a therapeutic agent in hyperoxaluria leading to urinary stones.

  2. Crystal structure of dimethylammonium hydrogen oxalate hemi(oxalic acid

    Directory of Open Access Journals (Sweden)

    Waly Diallo

    2015-05-01

    Full Text Available Single crystals of the title salt, Me2NH2+·HC2O4−·0.5H2C2O4, were isolated as a side product from the reaction involving Me2NH, H2C2O4 and Sn(n-Bu3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH22C2O4 salt and Sn(CH33Cl in a 2:1 ratio in ethanol. The asymmetric unit comprises a dimethylammonium cation (Me2NH2+, an hydrogenoxalate anion (HC2O4−, and half a molecule of oxalic acid (H2C2O4 situated about an inversion center. From a supramolecular point of view, the three components interact together via hydrogen bonding. The Me2NH2+ cations and the HC2O4− anions are in close proximity through bifurcated N—H...(O,O hydrogen bonds, while the HC2O4− anions are organized into infinite chains via O—H...O hydrogen bonds, propagating along the a-axis direction. In addition, the oxalic acid (H2C2O4 molecules play the role of connectors between these chains. Both the carbonyl and hydroxyl groups of each diacid are involved in four intermolecular interactions with two Me2NH2+ and two HC2O4− ions of four distinct polymeric chains, via two N—H...O and two O—H...O hydrogen bonds, respectively. The resulting molecular assembly can be viewed as a two-dimensional bilayer-like arrangement lying parallel to (010, and reinforced by a C—H...O hydrogen bond.

  3. Scientific Opinion on the safety assessment of the substance adipic acid dihydrazide, CAS No 1071-93-8, for use in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2015-01-01

    Full Text Available This scientific opinion of EFSA’s Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF deals with the risk assessment of the additive adipic acid dihydrazide, CAS No 1071-93-8, FCM substance No 987 for use as a crosslinker for acrylic polymer with keto side groups coated on polyolefins and adhesives in laminates made from plastics. The coating is not for direct food contact but used in inner layers of plastics laminates which are intended to be used for all types of foodstuffs at all time-temperature conditions applicable according to the laminate’s properties. Specific migration of the substance was measured from a coated low-density polyethylene (LDPE film, the substance was not detectable (limit of detection (LOD 0.019 mg/kg with the food simulants 3 % acetic acid, 10 % ethanol for 10 days at 40 °C and isooctane for 2 days at 20 °C. According the in vitro and in vivo studies available the substance is not considered genotoxic. Based on an in vivo micronucleus test, the substance is not considered to be clastogenic/aneugenic under the tested conditions. The CEF Panel concluded that there is no safety concern for the consumer if the substance is used as a crosslinker for non-self-supporting coatings on polyolefins and adhesives for laminates not in direct contact with food and its migration does not exceed 0.050 mg/kg food.

  4. A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea:Effect of Solvent and Catalyst

    Institute of Scientific and Technical Information of China (English)

    WANG,Xin-Kui(王心葵); YAN,Shi-Run(闫世润); CAO,Yong(曹勇); FAN,Kang-Nian(范康年); HE,He-Yong(贺鹤勇); KANG,Mao-Qing(亢茂青); PENG,Shao-Yi(彭少逸)

    2004-01-01

    A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.

  5. 1H NMR spectra of N-methyl-4-tolyl-1-(4-bromonaphthylamine and N-phenyl-1-(4-bromonaphthylamine: a combined experimental and theoretical study

    Directory of Open Access Journals (Sweden)

    Sergiy I. Okovytyy

    2014-03-01

    Full Text Available Theoretical investigations of the conformational properties and 1H NMR chemical shifts for N-methyl-4-tolyl-1-(4-bromonaphthylamine and N-phenyl-1-(4-bromonaphthylamine are reported. The calculations were performed at the DFT level (PBE1PBE functional using magnetically consistent 6-31G## and STO##-3Gmag basis sets. Conformational properties of the amines were studied using potential energy surface scanning. Chemical shifts were calculated using the GIAO and CSGT methods and averaged in proportion to the population of the corresponding conformations. Solvent effects (CDCl3 were accounted via PCM method. The obtained results allowed to assign the 1H NMR signals for the naphthalene moiety, which could not be done based on the experimental data alone.

  6. A novel 2-(2-Formyl-4-methyl-phenoxy)-N-phenyl-acetamide-based fluorescence turn-on chemosensor for selenium determination with high selectivity and sensitivity

    Science.gov (United States)

    Song, Cairui; Fei, Qiang; Shan, Hongyan; Feng, Guodong; Cui, Minghui; Liu, Yameng; Huan, Yanfu

    2013-12-01

    A novel turn-on fluorescent chemosensor, 2-(2-Formyl-4-methyl-phenoxy)-N-phenyl-acetamide (FMPPA) was designed and synthesized, and its photophysical properties were characterized. Upon coordination with Se (IV), the chemosensor showed incredible fluorescence enhancement (turn-on), other alkali, alkaline earth, transitional metal ions, and common anions including Li+, Na+, K+, Rb+, Cs+, Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Ni2+, Cu2+, Cd2+, Zn2+, Mn2+, As3+, Pt4+, V5+, Fe3+, Mo6+, Al3+, CO32-, Cl-, SCN-, AC-, NO3-, F-, SO42- had no significant interference on Se (IV) determination. The chemosensor exhibits a dynamic response range for Se (IV) from 3.32 × 10-7 to 2.63 × 10-6 M, with a detection limit of 9.38 × 10-9 M (3σ).

  7. Discovery of 5-substituted tetrahydronaphthalen-2yl-methyl with N-phenyl-N-(piperidin-4-yl)propionamide derivatives as potent opioid receptor ligands.

    Science.gov (United States)

    Deekonda, Srinivas; Wugalter, Lauren; Kulkarni, Vinod; Rankin, David; Largent-Milnes, Tally M; Davis, Peg; Bassirirad, Neemah M; Lai, Josephine; Vanderah, Todd W; Porreca, Frank; Hruby, Victor J

    2015-09-15

    A new series of novel opioid ligands have been designed and synthesized based on the 4-anilidopiperidine scaffold containing a 5-substituted tetrahydronaphthalen-2yl)methyl group with different N-phenyl-N-(piperidin-4-yl)propionamide derivatives to study the biological effects of these substituents on μ and δ opioid receptor interactions. Recently our group reported novel 4-anilidopiperidine analogues, in which several aromatic ring-contained amino acids were conjugated with N-phenyl-N-(piperidin-4-yl)propionamide and examined their biological activities at the μ and δ opioid receptors. In continuation of our efforts in these novel 4-anilidopiperidine analogues, we took a peptidomimetic approach in the present design, in which we substituted aromatic amino acids with tetrahydronaphthalen-2yl methyl moiety with amino, amide and hydroxyl substitutions at the 5th position. In in vitro assays these ligands, showed very good binding affinity and highly selective toward the μ opioid receptor. Among these, the lead ligand 20 showed excellent binding affinity (2 nM) and 5000 fold selectivity toward the μ opioid receptor, as well as functional selectivity in GPI assays (55.20 ± 4.30 nM) and weak or no agonist activities in MVD assays. Based on the in vitro bioassay results the lead compound 20 was chosen for in vivo assessment for efficacy in naïve rats after intrathecal administration. Compound 20 was not significantly effective in alleviating acute pain. This discrepancy between high in vitro binding affinity, moderate in vitro activity, and low in vivo activity may reflect differences in pharmacodynamics (i.e., engaging signaling pathways) or pharmacokinetics (i.e., metabolic stability). In sum, our data suggest that further optimization of this compound 20 is required to enhance in vivo activity.

  8. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor

    Science.gov (United States)

    Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei

    2014-01-01

    A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process.

  9. Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...

    African Journals Online (AJOL)

    ADOWIE PERE

    acid and ammonium oxalate on the prevalence of microorganisms and removal of ... of water and applied at different time intervals; application on a day prior to .... and residual soil composition after plant exposure for 3 months. Treatment. C.

  10. Chronic metabolic acidosis reduces urinary oxalate excretion and promotes intestinal oxalate secretion in the rat.

    Science.gov (United States)

    Whittamore, Jonathan M; Hatch, Marguerite

    2015-11-01

    Urinary oxalate excretion is reduced in rats during a chronic metabolic acidosis, but how this is achieved is not clear. In this report, we re-examine our prior work on the effects of a metabolic acidosis on urinary oxalate handling [Green et al., Am J Physiol Ren Physiol 289(3):F536-F543, 2005], offering a more detailed analysis and interpretation of the data, together with new, previously unpublished observations revealing a marked impact on intestinal oxalate transport. Sprague-Dawley rats were provided with 0.28 M ammonium chloride in their drinking water for either 4 or 14 days followed by 24 h urine collections, blood-gas and serum ion analysis, and measurements of (14)C-oxalate fluxes across isolated segments of the distal colon. Urinary oxalate excretion was significantly reduced by 75% after just 4 days compared to control rats, and this was similarly sustained at 14 days. Oxalate:creatinine clearance ratios indicated enhanced net re-absorption of oxalate by the kidney during a metabolic acidosis, but this was not associated with any substantive changes to serum oxalate levels. In the distal colon, oxalate transport was dramatically altered from net absorption in controls (6.20 ± 0.63 pmol cm(-2) h(-1)), to net secretion in rats with a metabolic acidosis (-5.19 ± 1.18 and -2.07 ± 1.05 pmol cm(-2) h(-1) at 4 and 14 days, respectively). Although we cannot rule out modifications to bi-directional oxalate movements along the proximal tubule, these findings support a gut-kidney axis in the management of oxalate homeostasis, where this shift in renal handling during a metabolic acidosis is associated with compensatory adaptations by the intestine.

  11. Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants 1

    Science.gov (United States)

    Nuss, Richard F.; Loewus, Frank A.

    1978-01-01

    l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined. When l-[1-14C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the 14C is released over a 24-hour period as 14CO2 and only a small portion is recovered as [14C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the 14C as [14C]oxalic acid and release very little 14CO2. Support for an intermediate role of oxalate in the release of 14CO2 from l-[1-14C]ascorbic acid is seen in the rapid release of 14CO2 by R. crispus and H. glomeratus seedlings labeled with [14C]oxalic acid. The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of 14C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-14C]- or l-[UL-14C]ascorbic acid. Theoretically, l-[1-14C]ascorbic acid will produce labeled oxalic acid containing three times as much 14C as l-[UL-14C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 ± 0.5 is obtained in duplicate experiments with six different species. PMID:16660342

  12. Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants.

    Science.gov (United States)

    Nuss, R F; Loewus, F A

    1978-04-01

    l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined.When l-[1-(14)C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the (14)C is released over a 24-hour period as (14)CO(2) and only a small portion is recovered as [(14)C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the (14)C as [(14)C]oxalic acid and release very little (14)CO(2). Support for an intermediate role of oxalate in the release of (14)CO(2) from l-[1-(14)C]ascorbic acid is seen in the rapid release of (14)CO(2) by R. crispus and H. glomeratus seedlings labeled with [(14)C]oxalic acid.The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of (14)C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-(14)C]- or l-[UL-(14)C]ascorbic acid. Theoretically, l-[1-(14)C]ascorbic acid will produce labeled oxalic acid containing three times as much (14)C as l-[UL-(14)C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 +/- 0.5 is obtained in duplicate experiments with six different species.

  13. The mechanics of hyaluronic acid/adipic acid dihydrazide hydrogel: towards developing a vessel for delivery of preadipocytes to native tissues.

    Science.gov (United States)

    Shoham, Naama; Sasson, Aviad Levi; Lin, Feng-Huei; Benayahu, Dafna; Haj-Ali, Rami; Gefen, Amit

    2013-12-01

    Promising treatment approaches in repairing tissue defects include implementation of regenerative medicine strategies, particularly delivery of preadipocytes to sites where adipose tissue damage needs to be repaired or where fat needs to be generated. In this study, we suggest that the injectable hyaluronic acid/adipic acid dihydrazide (HA/ADH) hydrogel may be an adipose-tissue-like material in terms of biological compatibility as well as mechanical behavior. First, we show that the hydrogel enables and supports growth, proliferation and differentiation of 3T3-L1 preadipocytes. Second, given that adipose tissue is a weight-bearing biological structure, we investigate the large deformation mechanical behavior of the hydrogel with and without embedded preadipocytes, by performing confined and unconfined compression tests and then calibrating a strain energy density (SED) function to the results. Four test groups were examined: (1) Hydrogel specimens right after the preparation without cells, (2) and (3) 3-days-cultured hydrogel specimens with and without cells, respectively, and (4) 6-days-cultured hydrogel specimens with cells. A one-term Ogden SED was found to adequately describe the hyperelastic behavior of the hydrogel specimens in all experimental groups. Importantly, we found that the mechanical properties of the hydrogel, when subjected to compression, are in good agreement with those of native adipose tissue, with the better fit occurring 3-6 days after preparation of the hydrogel. Third, computational finite element studies of the mechanical (stress-strain) behavior of the HA/ADH hydrogel when containing mature adipocytes indicated that the stiffnesses of the constructs were mildly affected by the presence of the adipocytes. Hence, we conclude that injectable HA/ADH hydrogel may serve as a vessel for protecting preadipocytes during, and at a short-term after delivery to native tissues, e.g. in research towards regenerative medicine in tissue reconstructions.

  14. Short communication: Urinary oxalate and calcium excretion by dogs and cats diagnosed with calcium oxalate urolithiasis

    NARCIS (Netherlands)

    Dijcker, J.C.; Kummeling, A.; Hagen-Plantinga, E.A.; Hendriks, W.H.

    2012-01-01

    Introduction Urine concentrations of oxalate and calcium play an important role in calcium oxalate (CaOx) urolith formation in dogs and cats, with high excretions of both substances increasing the chance of CaOx urolithiasis. In 17 CaOx-forming dogs, urine calcium:creatinine ratio (Ca:Cr) was found

  15. Influence of a low- and a high-oxalate vegetarian diet on intestinal oxalate absorption and urinary excretion.

    Science.gov (United States)

    Thomas, E; von Unruh, G E; Hesse, A

    2008-09-01

    To compare quantitatively the effect of a low- and a high-oxalate vegetarian diet on intestinal oxalate absorption and urinary excretion. Eight healthy volunteers (three men and five women, mean age 28.6+/-6.3) were studied. Each volunteer performed the [(13)C(2)]oxalate absorption test thrice on a low-oxalate mixed diet, thrice on a low-oxalate vegetarian diet and thrice on a high-oxalate vegetarian diet. For each test, the volunteers had to adhere to an identical diet and collect their 24-h urines. In the morning of the second day, a capsule containing [(13)C(2)]oxalate was ingested. On the low-oxalate vegetarian diet, mean intestinal oxalate absorption and urinary oxalate excretion increased significantly to 15.8+/-2.9% (P=0.012) and 0.414+/-0.126 mmol/day (P=0.012), compared to the mixed diet. On the high-oxalate vegetarian diet, oxalate absorption (12.5+/-4.6%, P=0.161) and urinary excretion (0.340+/-0.077 mmol/day, P=0.093) did not change significantly, compared to the mixed diet. A vegetarian diet can only be recommended for calcium oxalate stone patients, if the diet (1) contains the recommended amounts of divalent cations such as calcium and its timing of ingestion to a meal rich in oxalate is considered and (2) excludes foodstuffs with a high content of nutritional factors, such as phytic acid, which are able to chelate calcium.

  16. High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2010-08-01

    Full Text Available The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to be capable of acting as a heterogeneous ice nucleus in both the deposition and immersion mode. We could confirm a high deposition mode ice activity for 0.03 to 0.8 μm sized oxalic acid dihydrate particles that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets. The critical saturation ratio with respect to ice required for deposition nucleation was found to be less than 1.1 and the size-dependent ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles that had crystallised from less supersaturated solution droplets and had been allowed to slowly grow in a supersaturated environment from still unfrozen oxalic acid solution droplets over a time period of several hours were found to be much poorer heterogeneous ice nuclei. We speculate that under these conditions a crystal surface structure with less-active sites for the initiation of ice nucleation was generated. Such particles partially proved to be almost ice-inactive in both the deposition and condensation mode. At times, the heterogeneous ice nucleation ability of oxalic acid dihydrate significantly changed when the particles had been processed in preceding cloud droplet activation steps. Such behaviour was also observed for the second investigated species, namely sodium oxalate. Our experiments address the atmospheric scenario

  17. Fabrication of a Ho3+-PVC membrane sensor based on N-phenyl-2-(thiophen-2-ylmethylene)hydrazinecarbothioamide for determination of holmium ions

    Institute of Scientific and Technical Information of China (English)

    Hassan Ali Zamani

    2011-01-01

    In this research, a new poly(vinyl chloride) (PVC) membrane sensor for Ho3+ ion based on N-phenyl-2-(thiophen-2-ylmethylene)hydrazinecarbothioamide (PHC) as an ionophore was prepared. This sensor demonstrated good selectivity and sensitivity towards the holmium ion in comparison with variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition and pH on the response properties of the electrode was investigated. In detail, the suggested sensor exhibited a Nernstian behavior (with a slope of 20.4 ± 0.3 mV decade-1) in the range of 1.0 × 10-6 to 1.0 × 10-2 mol/L with a detection limit of 6.2 × 10-7 mol/L. The response time was relatively quick in the whole concentration range (~5 s). The sensor usage was found to be at least 10 weeks in a pH range of 3.3-10.9. It was successfully applied in determination of fluoride ions in mouth wash preparations.

  18. Synthesis, characterization and DNA-binding studies on La(III) and Ce(III) complexes containing ligand of N-phenyl-2-pyridinecarboxamide

    Science.gov (United States)

    He, Xin-Qian; Lin, Qiu-Yue; Hu, Rui-Ding; Lu, Xiao-Hong

    2007-09-01

    La(III) and Ce(III) complexes containing ligand of N-phenyl-2-pyridinecarboxamide (HL) were synthesized and characterized by elemental analyses, conductivity measurement, IR spectra and thermal analysis. The general formulas of the complexes were [Ln(HL) 3(H 2O) 2](NO 3) 3·2H 2O [Ln = La(III), Ce(III)]. The results indicated that the oxygen of carbonyl and the nitrogen of pyridyl coordinated to Ln(III), and there were also two water molecules taking part in coordination. Ln(III) and HL formed 1:3 chelate complexes and the coordination number was eight. The interaction between the complexes and DNA was studied by means of UV-vis spectra, fluorescence spectra, SERS spectra and agarose gel electrophoresis. The results showed that complexes can bind to DNA. The binding ability decreased in following order: La(III) complex, Ce(III) complex, and HL. The interaction modes between DNA and the three compounds were found to be mainly intercalative.

  19. Rare earth complexes with a novel ligand N-(naphthalen-2-yl)- N-phenyl-2-(quinolin-8-yloxy)acetamide: Preparation and spectroscopic studies

    Science.gov (United States)

    Wu, Wei-Na; Tang, Ning; Yan, Lan

    2008-12-01

    Six complexes of rare earth nitrates (Ln = La, Sm, Eu, Gd, Tb, Dy) with a new amide type ligand, N-(naphthalen-2-yl)- N-phenyl-2-(quinolin-8-yloxy)acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and and 1H NMR spectra. Under excitation, Eu(III) and Sm(III) complexes exhibited strong red emissions. And the luminescence intensity of Sm(III) complex is higher than that of Eu(III) complex. Thus the Eu(III) and Sm(III) complexes are the potential light conversion agent. However, the Tb(III) and Dy(III) complexes cannot exhibit characteristic emissions of terbium and dysprosium ions, respectively. The results of phosphorescence spectrum show that the triplet-state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. In addition, the luminescence of the Eu(III) complex is also relatively strong in highly diluted tetrahydrofuran solution (2 × 10 -4 mol/L) compared with the powder. This is not only due to the solvate effects but also to the changes of the structure of the Eu(III) complex after being dissolved into the solvents. Furthermore, owing to the co-luminescence effect, the proper La(III) or Gd(III) doped Eu(III) complexes show stronger luminescence than the pure Eu(III) complex.

  20. Mixed Ligand Complexes of N-Methyl-N-phenyl Dithiocarbamate: Synthesis, Characterisation, Antifungal Activity, and Solvent Extraction Studies of the Ligand.

    Science.gov (United States)

    Ekennia, Anthony C; Onwudiwe, Damian C; Ume, Cyril; Ebenso, Eno E

    2015-01-01

    A series of mixed ligand dithiocarbamate complexes with a general formula [ML2(py)2], where M = Mn(II), Co(II), Ni(II), and Cu(II), py = pyridine, and L = N-methyl-N-phenyl dithiocarbamate have been prepared and characterised by elemental analysis, FTIR and Uv spectroscopy, magnetic moment, and thermogravimetric and conductance analysis. The infrared spectra showed that symmetrical bidentate coordination occurred with the dithiocarbamate moiety through the sulfur atoms, while neutral monodentate coordination occurred through the nitrogen atom for the pyridine molecule in the complexes. The electronic spectra, elemental analysis, and magnetic moment results proved that the complexes adopted octahedral geometry. The conductance measurement showed that the complexes are nonelectrolytes proving their nonionic nature. The compounds were screened for three human pathogenic fungi: Aspergillus flavus, Aspergillus niger, and Candida albicans. The cobalt complex showed the best antifungal activity among the test compounds. Liquid-liquid extractive abilities of the ligand towards copper and nickel ions in different solvent media were investigated. The ligand showed a strong binding affinity towards the metals ions with an extractive efficiency of about 99%.

  1. Effects of copper sulfate, hydrogen peroxide and N-phenyl-2-naphthylamine on oxidative stress and the expression of genes involved photosynthesis and microcystin disposition in Microcystis aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Qian Haifeng; Yu Shuqiong; Sun Zhengqi; Xie Xiucai; Liu Weiping [College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310032 (China); Fu Zhengwei, E-mail: azwfu2003@yahoo.com.cn [College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, 310032 (China)

    2010-09-01

    Algal blooms have been increasing in prevalence all over the world, destroying ecosystems and placing other organisms at risk. Chemical remediation is one of most important methods of controlling algal bloom formation. The effects of copper sulfate, hydrogen peroxide (H{sub 2}O{sub 2}) and N-phenyl-2-naphthylamine on photosynthesis-related and microcystin-related gene transcription and physiological changes of Microcystis aeruginosa were analyzed. The results suggest that transcription of psaB, psbD1 and rbcL was inhibited by the three algaecides, which blocked the electron transport chain, significantly enhanced reactive oxygen species (ROS) accumulation and overwhelmed the antioxidant system. The increase in ROS destroyed pigment synthesis and membrane integrity, which inhibited or killed the algal cells. Furthermore, H{sub 2}O{sub 2} treatment down-regulated mcyD transcription, which indicated a decrease in the microcystin level in the cells. Our results demonstrate that H{sub 2}O{sub 2} has the greatest potential as an algaecide because it not only inhibits algae growth but may reduce microcystin synthesis.

  2. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration

  3. A CONTROLLED METABOLIC DIET REDUCES CALCIUM OXALATE SUPERSATURATION BUT NOT OXALATE EXCRETION AFTER BARIATRIC SURGERY

    Science.gov (United States)

    Pang, Ran; Linnes, Michael; O’Connor, Helen M.; Li, Xujian; Bergstralh, Eric; Lieske, John C.

    2012-01-01

    Objective To identify the effect of controlled metabolic diet on reducing urinary calcium oxalate supersaturation in subjects with hyperoxaluric nephrolithiasis after potentially malabsorptive forms of bariatric surgery. Materials and Methods Subjects with a history of CaOx kidney stones and mild hyperoxaluria after bariatric surgery (n=9) collected baseline 24-hour urine samples while on a free choice diet. They were then placed on a controlled diet low in oxalate (70 – 80 mg/day), normal in calcium (1000 mg/day), and moderate in protein prior to 2 final 24-hour urine collections. Results Overall urinary CaOx supersaturation fell from 1.97 ± 0.49 delta Gibbs (DG) on the free choice diet to 1.13 ± 0.75 DG on the controlled diet (P0.05), contributing to the significant CaOx supersaturation change. Conclusions A controlled metabolic diet normal in calcium, moderate in protein and reduced in oxalate can positively impact urinary CaOx supersaturation after bariatric surgery. However, this diet did not appear to decrease urinary oxalate excretion. Therefore, restriction of dietary oxalate alone may not be enough to reduce urinary oxalate excretion to normal levels in this group of known enteric hyperoxaluric patients. Additional strategies may be necessary, such as use of oral calcium supplements as oxalate binders and a lower fat diet. PMID:22554593

  4. Controlled metabolic diet reduces calcium oxalate supersaturation but not oxalate excretion after bariatric surgery.

    Science.gov (United States)

    Pang, Ran; Linnes, Michael P; O'Connor, Helen M; Li, Xujian; Bergstralh, Eric; Lieske, John C

    2012-08-01

    To identify the effect of a controlled metabolic diet on reducing urinary calcium oxalate (CaOx) supersaturation in subjects with hyperoxaluric nephrolithiasis after potentially malabsorptive forms of bariatric surgery. Subjects with a history of CaOx kidney stones and mild hyperoxaluria after bariatric surgery (n = 9) collected baseline 24-hour urine samples while consuming a free choice diet. They were then instructed to consume a controlled diet low in oxalate (70-80 mg/d), normal in calcium (1000 mg/d), and moderate in protein before 2 final 24-hour urine collections. Overall, the urinary CaOx supersaturation decreased from 1.97 ± 0.49 delta Gibbs (DG) with the free choice diet to 1.13 ± 0.75 DG with the controlled diet (P .05), contributing to the significant CaOx supersaturation change. A controlled metabolic diet normal in calcium, moderate in protein, and reduced in oxalate can positively affect urinary CaOx supersaturation after bariatric surgery. However, this diet did not appear to decrease urinary oxalate excretion. Therefore, restriction of dietary oxalate alone might not be enough to reduce urinary oxalate excretion to normal levels in this group of patients with known enteric hyperoxaluria. Additional strategies could be necessary, such as the use of oral calcium supplements as oxalate binders and a lower fat diet. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Vibrational spectra of the two hydrates of strontium oxalate.

    Science.gov (United States)

    D'Antonio, Maria C; Torres, María M; Palacios, Daniel; González-Baró, Ana C; Baran, Enrique J

    2015-02-25

    The infrared and Raman spectra of the two hydrates of strontium oxalate, SrC2O4⋅H2O and SrC2O4⋅2H2O, were recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of the related calcium oxalates and other previously investigated metallic oxalates.

  6. Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2011-05-01

    Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

  7. Insight into the template effect of vesicles on the laccase-catalyzed oligomerization of N-phenyl-1,4-phenylenediamine from Raman spectroscopy and cyclic voltammetry measurements

    Science.gov (United States)

    Ležaić, Aleksandra Janoševic; Luginbühl, Sandra; Bajuk-Bogdanović, Danica; Pašti, Igor; Kissner, Reinhard; Rakvin, Boris; Walde, Peter; Ćirić-Marjanović, Gordana

    2016-08-01

    We report about the first Raman spectroscopy study of a vesicle-assisted enzyme-catalyzed oligomerization reaction. The aniline dimer N-phenyl-1,4-phenylenediamine (= p-aminodiphenylamine, PADPA) was oxidized and oligomerized with Trametes versicolor laccase and dissolved O2 in the presence of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) vesicles (80-100 nm diameter) as templates. The conversion of PADPA into oligomeric products, poly(PADPA), was monitored during the reaction by in situ Raman spectroscopy. The results obtained are compared with UV/vis/NIR and EPR measurements. All three complementary methods indicate that at least some of the poly(PADPA) products, formed in the presence of AOT vesicles, resemble the conductive emeraldine salt form of polyaniline (PANI-ES). The Raman measurements also show that structural units different from those of “ordinary” PANI-ES are present too. Without vesicles PANI-ES-like products are not obtained. For the first time, the as-prepared stable poly(PADPA)-AOT vesicle suspension was used directly to coat electrodes (without product isolation) for investigating redox activities of poly(PADPA) by cyclic voltammetry (CV). CV showed that poly(PADPA) produced with vesicles is redox active not only at pH 1.1-as expected for PANI-ES-but also at pH 6.0, unlike PANI-ES and poly(PADPA) synthesized without vesicles. This extended pH range of the redox activity of poly(PADPA) is important for applications.

  8. Insight into the template effect of vesicles on the laccase-catalyzed oligomerization of N-phenyl-1,4-phenylenediamine from Raman spectroscopy and cyclic voltammetry measurements.

    Science.gov (United States)

    Ležaić, Aleksandra Janoševic; Luginbühl, Sandra; Bajuk-Bogdanović, Danica; Pašti, Igor; Kissner, Reinhard; Rakvin, Boris; Walde, Peter; Ćirić-Marjanović, Gordana

    2016-08-26

    We report about the first Raman spectroscopy study of a vesicle-assisted enzyme-catalyzed oligomerization reaction. The aniline dimer N-phenyl-1,4-phenylenediamine (= p-aminodiphenylamine, PADPA) was oxidized and oligomerized with Trametes versicolor laccase and dissolved O2 in the presence of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) vesicles (80-100 nm diameter) as templates. The conversion of PADPA into oligomeric products, poly(PADPA), was monitored during the reaction by in situ Raman spectroscopy. The results obtained are compared with UV/vis/NIR and EPR measurements. All three complementary methods indicate that at least some of the poly(PADPA) products, formed in the presence of AOT vesicles, resemble the conductive emeraldine salt form of polyaniline (PANI-ES). The Raman measurements also show that structural units different from those of "ordinary" PANI-ES are present too. Without vesicles PANI-ES-like products are not obtained. For the first time, the as-prepared stable poly(PADPA)-AOT vesicle suspension was used directly to coat electrodes (without product isolation) for investigating redox activities of poly(PADPA) by cyclic voltammetry (CV). CV showed that poly(PADPA) produced with vesicles is redox active not only at pH 1.1-as expected for PANI-ES-but also at pH 6.0, unlike PANI-ES and poly(PADPA) synthesized without vesicles. This extended pH range of the redox activity of poly(PADPA) is important for applications.

  9. Structural and in vitro cytotoxicity studies on 1H-benzimidazol-2-ylmethyl-N-phenyl amine and its Pd(II) and Pt(II) complexes

    Science.gov (United States)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2011-10-01

    [MLCl 2]· zH 2O (L = (1H-benzimidazol-2-ylmethyl)-N-phenyl amine; M = Pd, z = 0; M = Pt, z = 1) and [PdL(OH 2) 2]·2X·zH 2O (X = Br, I, NO 3, z = 0; X = SCN, z = 1) complexes were synthesized as potential anticancer compounds and characterized by elemental analysis, spectral and thermal methods. FT-IR and 1H NMR studies revealed that the benzimidazole L is coordinated to the metal ions via the pyridine-type nitrogen (N py) of the benzimidazole ring and secondary amino group (NH sec). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and 1H NMR of the benzimidazole L and its complexes were carried out by density functional theory using B3LYP functional combined with 6-31G(d) and LANL2DZ basis sets. Natural bond orbitals (NBOs) and frontier molecular orbitals were performed at B3LYP/LANL2DZ level of theory. The synthesized ligand, in comparison to its metal complexes was screened for its antibacterial activity. The benzimidazole L is more toxic against the bacterium Staphylococcus aureus (MIC = 58 μg/mL) than the standard tetracycline (MIC = 82 μg/mL). The complexes showed cytotoxicity against breast cancer, Colon Carcinoma, and human heptacellular Carcinoma cells. The platinum complex ( 6) displays cytotoxicity (IC 50 = 12.4 μM) against breast cancer compared with that reported for cis-platin 9.91 μM.

  10. Nutrition and oxalate metabolism in cats

    NARCIS (Netherlands)

    Dijcker, J.C.

    2013-01-01

    Over the past 30 years, a progressive increase in calcium oxalate (CaOx) urolith prevalence is reported in cats and dogs diagnosed with urolithiasis. This increase in prevalence appears to have occurred since dietary modifications were introduced to address magnesium ammonium phosphate urolithiasis.

  11. Nutrition and oxalate metabolism in cats

    NARCIS (Netherlands)

    Dijcker, J.C.|info:eu-repo/dai/nl/315029412

    2013-01-01

    Over the past 30 years, a progressive increase in calcium oxalate (CaOx) urolith prevalence is reported in cats and dogs diagnosed with urolithiasis. This increase in prevalence appears to have occurred since dietary modifications were introduced to address magnesium ammonium phosphate urolithiasis.

  12. Electron imaging of calcium oxalate crystals in beagle dogs’ urine

    Directory of Open Access Journals (Sweden)

    Walaa I. Mohamaden

    2014-06-01

    Full Text Available Calcium oxalate crystalluria appears to be a common problem in most of small animal clinics. This current study aimed at inducing a condition of oxalate crystalluria in beagles and record the primary changes in canine blood and urine on response to oxalates injection. 15 dogs were divided into two groups; those in the treatment group were injected intravenously with 0.5 M potassium oxalate and the dogs of control group were injected with physiological saline for five successive days. Urine test revealed a significant decrease in urinary creatinine and urinary urea nitrogen levels. The ultrastructural examination of urine sediment showed typical and atypical phases of calcium oxalate crystals and the X-ray defractionation of these crystals showed high content of calcium in addition to other minerals. Therefore potassium oxalate injection may provide an example of calcium oxalate crystalluria which may answer some question around the pathogenesis of this problem in dogs.

  13. Screening of oxalate degrading lactic acid bacteria of food origin

    Directory of Open Access Journals (Sweden)

    Nicoletta Murru

    2017-04-01

    Full Text Available A screening for oxalate degrading abilities was initially carried on within Lactic Acid Bacteria cultures of different food origin. Seventy-nine strains were drop-inoculated onto MRS agar plates containing calcium oxalate. By comparing colonies diameters, 31 strains were used to inoculate, in parallel, MRS and MRS modified by sodium oxalate addition. Differences in the strains’ growth were assessed by colony forming unit counts. For two strains, the growth in oxalate enriched medium was significantly higher; while, for eleven strains an opposite behaviour was recorded. Two strains – probiotic Lactobacillus rhamnosus LbGG and Enterococcus faecalis 59 – were chosen. The first strain appeared to be able to metabolize oxalate more efficiently than the other tested cultures, while strain 59 appeared unable to gather advantage by oxalates and, indeed, appeared to be inhibited by the salt presence in the medium. Outcomes revealed that higher glucose concentrations may favour oxalates utilization. In MRS with oxalate, but without glucose, citrate was completely metabolized. Evaluation along time confirmed that the oxalate degradation is more significant in presence of glucose. Outcomes may represent a good start for the development of a safe and even probiotic culture able to lower the oxalates content of food.

  14. Crystal and molecular structures of alkali oxalates: first proof of a staggered oxalate anion in the solid state.

    Science.gov (United States)

    Dinnebier, Robert E; Vensky, Sascha; Panthöfer, Martin; Jansen, Martin

    2003-03-10

    The molecular and crystal structures of solvent-free potassium, rubidium, and cesium oxalates have been determined ab initio from high-resolution synchrotron and X-ray laboratory powder patterns. In the case of potassium oxalate K(2)C(2)O(4) (a = 10.91176(7) A, b = 6.11592(4) A, c = 3.44003(2) A, orthorhombic, Pbam, Z = 2), the oxalate anion is planar, whereas in cesium oxalate Cs(2)C(2)O(4) (a = 6.62146(5) A, b = 11.00379(9) A, c = 8.61253(7) A, beta = 97.1388(4) degrees, monoclinic, P2(1)/c, Z = 4) it exhibits a staggered conformation. For rubidium oxalate at room temperature, two polymorphs exist, one (beta-Rb(2)C(2)O(4)) isotypic to potassium oxalate (a = 11.28797(7) A, b = 6.29475(4) A, c = 3.62210(2) A, orthorhombic, Pbam, Z = 2) and the other (alpha-Rb(2)C(2)O(4)) isotypic to cesium oxalate (a = 6.3276(1) A, b = 10.4548(2) A, c = 8.2174(2) A, beta = 98.016(1) degrees, monoclinic, P2(1)/c, Z = 4). The potassium oxalate structure can be deduced from the AlB(2) type, and the cesium oxalate structure from the Hg(99)As type, respectively. The relation between the two types of crystal structures and the reason for the different conformations of the oxalate anion are discussed.

  15. Simulation of calcium oxalate stone in vitro

    Institute of Scientific and Technical Information of China (English)

    欧阳健明; 姚秀琼; 苏泽轩; 崔福斋

    2003-01-01

    Crystallization of calcium oxalate is studied mainly in the diluted healthy urine using scanning electron microscopy (SEM), and is compared with the crystallization in the diluted pathological urine. It suggests that the average sizes of calcium oxalate crystals are not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Only in the concentration range of 0.60-0.90 mmol/L can larger size of CaOx crystals appear. When the concentrations of Ca2+ and Ox2- ions are 1.20, 0.80, 0.60, 0.30 and 0.15 mmol/L in the healthy urine, the average sizes of calcium oxalate crystallites are 9.5 × 6.5, 20.0 × 13.5 and 15.0 μm × 10.0 μm, respectively, for the former three samples after 6 d crystallization. No crystal appears even after 30 d crystallization for the samples of concentrations of 0.30 and 0.15 mmol/L due to their low supersaturations. The results theoretically explain why the probability of stone forming is clinically not in direct proportion to the concentrations of Ca 2+ and Ox2- ions. Laser scattering technology also confirms this point. The reason why healthy human has no risk of urinary stone but stone-formers have is that there are more urinary macromolecules in healthy human urines than that in stone-forming urines. These macromolecules may control the transformation in CaOx crystal structure from monohydrate calcium oxalate (COM) to dihydrate calcium oxalate (COD). COD has a weaker affinity for renal tubule cell membranes than COM. No remarkable effect of the crystallization time is observed on the crystal morphology of CaOx. All the crystals are obtuse hexagon. However, the sizes and the number of CaOx crystals can be affected by the crystallization time. In the early stage of crystallization (1-6 d), the sizes of CaOx crystals increase and the number of crystal particles changes little as increasing the crystallization time due to growth control. In the middle and late stages (6-30 d), the number of crystals increases markedly while the

  16. Kinetic study of oxalic acid inhibition on enzymatic browning.

    Science.gov (United States)

    Son, S M; Moon, K D; Lee, C Y

    2000-06-01

    Oxalic acid has a strong antibrowning activity. The inhibitory pattern on catechol-PPO model system appeared to be competitive, with a K(i) value of 2.0 mM. When the PPO was incubated with oxalic acid, the activity was not recovered via dialysis, but the inactivated enzyme partially recovered its activity when cupric ion was added. Comparing the relative antibrowning effectiveness of oxalic acid with other common antibrowning agents, oxalic acid with I(50) value of 1.1 mM is as effective as kojic acid and more potent than cysteine and glutathione.

  17. Treatment of simulated wastewater containing n-phenyl-n-isopropyl-p-phenylenediamine using electrolysis system with Ti/TiRuO2 electrodes

    Directory of Open Access Journals (Sweden)

    Thelma Helena Inazaki

    2004-11-01

    Full Text Available This study investigated the effects of the electrolytic treatment in the simulated wastewater with aromatic amine n-phenyl-n-isopropyl-p-phenylenediamine (Flexzone 3P® using Ti/TiRuO2 electrodes under 0.025 A/cm² (DC for different electrolysis durations (5; 15; 30; 45 and 60 min. Conductivity, pH, UV-visible spectra, gas chromatograms, toxicity and biodegradation tests were carried out. During the electrolytic treatment the pH decreased and conductivity increased slightly. After 60 min of electrolysis, the concentration of Flexzone 3P decreased by 65.1%. UV-vis spectra and chromatograms of simulated wastewater showed changes in the molecular structure of the aromatic amine. After 5 and 15 min of electrolysis, the simulated wastewater containing the Flexzone 3P showed detoxification by Saccharomyces cerevisiae toxicity test. The electrolysis of 5 min improved the biodegradation of the simulated wastewater containing Flexzone 3P.O presente trabalho apresenta os resultados dos tratamentos eletrolíticos (05; 15; 30; 45 e 60 min no efluente simulado com o composto Flexzone 3P, utilizando-se eletrodos de Ti/TiRuO2, sob 0,025 A cm-2. Após as eletrólises, foram feitas análises de pH, condutividade, espectrofotometria no UV-vis, análise por cromatografia gasosa, ensaios de toxicidade utilizando Saccharomyces cerevisiae e ensaio de respirometria de Bartha. O pH dos efluentes foi diminuindo à medida que aumentou- se o tempo de eletrólise, ao contrário da condutividade, a qual apresentou pequeno aumento. Verificou-se que após 60 min de tratamento foi obtida diminuição da concentração do composto Flexzone 3P em 65,1%. Analisando-se os espectros de UV-vis e cromatogramas do efluente após realização do tratamento eletrolítico, concluiu-se que ocorreram oxidações e transformações de funções orgânicas do composto, durante os tratamentos. Após a realização do tratamento eletrolítico, o efluente simulado apresentou diminuição da

  18. Influence of nutrition on feline calcium oxalate urolithiasis with emphasis on endogenous oxalate synthesis

    NARCIS (Netherlands)

    Dijcker, J.C.; Plantinga, E.A.; Baal, van J.; Hendriks, W.H.

    2011-01-01

    The prevalence of calcium oxalate (CaOx) uroliths detected in cats with lower urinary tract disease has shown a sharp increase over the last decades with a concomitant reciprocal decrease in the occurrence of struvite (magnesium ammonium phosphate) uroliths. CaOx stone-preventative diets are availab

  19. Crystal structure of (ferrocenylmethyldimethylammonium hydrogen oxalate

    Directory of Open Access Journals (Sweden)

    Mamadou Ndiaye

    2015-08-01

    Full Text Available The crystal structure of the title salt, [Fe(C5H5(C8H13N](HC2O4, consists of discrete (ferrocenylmethyldimethylammonium cations and hydrogen oxalate anions. The anions are connected through a strong O—H...O hydrogen bond, forming linear chains running parallel to [100]. The cations are linked to the anions through bifurcated N—H...(O,O′ hydrogen bonds. Weak C—H...π interactions between neighbouring ferrocenyl moieties are also observed.

  20. Calcium Oxalate Accumulation in Malpighian Tubules of Silkworm (Bombyx mori)

    Science.gov (United States)

    Wyman, Aaron J.; Webb, Mary Alice

    2007-04-01

    Silkworm provides an ideal model system for study of calcium oxalate crystallization in kidney-like organs, called Malpighian tubules. During their growth and development, silkworm larvae accumulate massive amounts of calcium oxalate crystals in their Malpighian tubules with no apparent harm to the organism. This manuscript reports studies of crystal structure in the tubules along with analyses identifying molecular constituents of tubule exudate.

  1. Oxalate Synthesis and Pyrolysis: A Colorful Introduction to Stoichiometry

    Science.gov (United States)

    Vannatta, Michael W.; Richards-Babb, Michelle; Sweeney, Robert J.

    2010-01-01

    Metal oxalate synthesis and pyrolysis provides an opportunity for students to (i) learn stoichiometry, (ii) experience the consequences of proper stoichiometric calculations and experimental techniques, and (iii) be introduced to the relevance of chemistry by highlighting oxalates in context, for example, usages and health effects. At our…

  2. Total and soluble oxalate content of some Indian spices.

    Science.gov (United States)

    Ghosh Das, Sumana; Savage, G P

    2012-06-01

    Spices, such as cinnamon, cloves, cardamom, garlic, ginger, cumin, coriander and turmeric are used all over the world as flavouring and colouring ingredients in Indian foods. Previous studies have shown that spices contain variable amounts of total oxalates but there are few reports of soluble oxalate contents. In this study, the total, soluble and insoluble oxalate contents of ten different spices commonly used in Indian cuisine were measured. Total oxalate content ranged from 194 (nutmeg) to 4,014 (green cardamom) mg/100 g DM, while the soluble oxalate contents ranged from 41 (nutmeg) to 3,977 (green cardamom) mg/100 g DM. Overall, the percentage of soluble oxalate content of the spices ranged from 4.7 to 99.1% of the total oxalate content which suggests that some spices present no risk to people liable to kidney stone formation, while other spices can supply significant amounts of soluble oxalates and therefore should be used in moderation.

  3. [Formation of oxalate in oxaliplatin injection diluted with infusion solutions].

    Science.gov (United States)

    Eto, Seiji; Yamamoto, Kie; Shimazu, Kounosuke; Sugiura, Toshimune; Baba, Kaori; Sato, Ayaka; Goromaru, Takeshi; Hagiwara, Yoshiaki; Hara, Keiko; Shinohara, Yoshitake; Takahashi, Kojiro

    2014-01-01

    Oxaliplatin use can cause acute peripheral neuropathy characterized by sensory paresthesias, which are markedly exacerbated by exposure to cold temperatures, and is a dose-limiting factor in the treatment of colorectal cancer.Oxalate is eliminated in a series of nonenzymatic conversions of oxaliplatin in infusion solutions or biological fluids.Elimination of oxalate from oxaliplatin has been suggested as one of the reasons for the development of acute neuropathy.In this study, we developed a high-performance liquid chromatography(HPLC)-based method to detect oxalate formation, and investigated the time dependent formation of oxalate in oxaliplatin diluted with infusion solutions.The results obtained showed that the amount of oxalate in the solution corresponded to 1.6% of oxaliplatin 8 h after oxaliplatin dilution with a 5% glucose solution. On the other hand, oxalate formation from oxaliplatin diluted with a saline solution was ten-fold higher than that from oxaliplatin diluted with the 5% glucose solution.Most patients who were intravenously injected with oxaliplatin experienced venous pain.As a preventive measure against venous pain, dexamethasone was added to the oxaliplatin injection.We measured the amount of oxalate formed in the dexamethasone-containing oxaliplatin injection diluted with a 5% glucose solution.The amount of oxalate formed when dexamethasone was added did not differ significantly from that formed when dexamethasone was not added.Thus, there are no clinical problems associated with the stability of oxaliplatin solutions.

  4. Production of oxalic acid by some fungi infected tubers.

    Science.gov (United States)

    Faboya, O; Ikotun, T; Fatoki, O S

    1983-01-01

    Oxalic acid (as oxalate) was detected in four tubers commonly used for food in Nigeria-Dioscorea rotundata (White yam), Solanum tuberosum (Irish potato), Ipomoea batatas (Sweet potato), and Manihot esculenta (cassava). Whereas healthy I. batata had the highest oxalic acid content, healthy M. esculenta contained the lowest. When all tubers were artifically inoculated with four fungi-Penicillium oxalicum CURIE and THOM, Aspergillus niger VAN TIEGH, A. flavus and A. tamarii KITA, there was an increase in oxalate content/g of tuber tissue. The greatest amount of oxalate was produced by P. oxalicum in D. rotundata tuber. Consistently higher amounts of oxalate were produced by the four fungi in infected sweet potato tuber than in any other tuber and consistently lower amounts of oxalate were produced by the four fungi in Irish potato tuber. Differences in the carbohydrate type present in the tubers and in the biosynthesis pathway are thought to be responsible for variation in the production of oxalate in the different tubers by the four fungi used.

  5. Oxalate Synthesis and Pyrolysis: A Colorful Introduction to Stoichiometry

    Science.gov (United States)

    Vannatta, Michael W.; Richards-Babb, Michelle; Sweeney, Robert J.

    2010-01-01

    Metal oxalate synthesis and pyrolysis provides an opportunity for students to (i) learn stoichiometry, (ii) experience the consequences of proper stoichiometric calculations and experimental techniques, and (iii) be introduced to the relevance of chemistry by highlighting oxalates in context, for example, usages and health effects. At our…

  6. OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-07-22

    The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

  7. Crystal growth methods dedicated to low solubility actinide oxalates

    Energy Technology Data Exchange (ETDEWEB)

    Tamain, C., E-mail: christelle.tamain@cea.fr [CEA, Nuclear Energy Division, Marcoule, RadioChemistry & Processes Department, F-30207 Bagnols sur Cèze (France); Arab-Chapelet, B. [CEA, Nuclear Energy Division, Marcoule, RadioChemistry & Processes Department, F-30207 Bagnols sur Cèze (France); Rivenet, M. [University Lille Nord de France, Unité de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, ENSCL-USTL, B.P. 90108, F-59652 Villeneuve d’Ascq Cedex (France); Grandjean, S. [CEA, Nuclear Energy Division, Marcoule, RadioChemistry & Processes Department, F-30207 Bagnols sur Cèze (France); Abraham, F. [University Lille Nord de France, Unité de Catalyse et de Chimie du Solide, UCCS UMR CNRS 8181, ENSCL-USTL, B.P. 90108, F-59652 Villeneuve d’Ascq Cedex (France)

    2016-04-15

    Two novel crystal growth syntheses dedicated to low solubility actinide-oxalate systems and adapted to glove box handling are described. These methods based on the use of precursors of either actinide metal or oxalic acid have been optimized on lanthanide systems (analogue of actinides(III)) and then assessed on real actinide systems. They allow the synthesis of several actinide oxalate single crystals, Am{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 3}·xH{sub 2}O, Th(C{sub 2}O{sub 4}){sub 2}·6H{sub 2}O, M{sub 2+x}[Pu{sup IV}{sub 2−x}Pu{sup III}{sub x}(C{sub 2}O{sub 4}){sub 5}]·nH{sub 2}O and M{sub 1−x}[Pu{sup III}{sub 1−x}Pu{sup IV}{sub x}(C{sub 2}O{sub 4}){sub 2}·H{sub 2}O]·nH{sub 2}O. It is the first time that these well-known compounds are formed by crystal growth methods, thus enabling direct structural studies on transuranic element systems and acquisition of basic data beyond deductions from isomorphic (or not) lanthanide compounds. Characterizations by X-ray diffraction, UV–visible solid spectroscopy, demonstrate the potentialities of these two crystal growth methods to obtain oxalate compounds. - Graphical abstract: Two new single crystal growth methods dedicated to actinide oxalate compounds. - Highlights: • Use of diester as oxalate precursor for crystal growth of actinide oxalates. • Use of actinide oxide as precursor for crystal growth of actinide oxalates. • Crystal growth of Pu(III) and Am(III) oxalates. • Crystal growth of mixed Pu(III)/Pu(IV) oxalates.

  8. Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II oxalate precursor layers

    Directory of Open Access Journals (Sweden)

    Kai Rückriem

    2016-06-01

    Full Text Available Copper(II oxalate grown on carboxy-terminated self-assembled monolayers (SAM using a step-by-step approach was used as precursor for the electron-induced synthesis of surface-supported copper nanoparticles. The precursor material was deposited by dipping the surfaces alternately in ethanolic solutions of copper(II acetate and oxalic acid with intermediate thorough rinsing steps. The deposition of copper(II oxalate and the efficient electron-induced removal of the oxalate ions was monitored by reflection absorption infrared spectroscopy (RAIRS. Helium ion microscopy (HIM reveals the formation of spherical nanoparticles with well-defined size and X-ray photoelectron spectroscopy (XPS confirms their metallic nature. Continued irradiation after depletion of oxalate does not lead to further particle growth giving evidence that nanoparticle formation is primarily controlled by the available amount of precursor.

  9. A new polymorph of magnesium oxalate dihydrate

    Directory of Open Access Journals (Sweden)

    Xue-An Chen

    2008-07-01

    Full Text Available In the asymmetric unit of the title compound, catena-poly[[diaquamagnesium(II]-μ-oxalato], [Mg(C2O4(H2O2]n, there is one Mg atom in an octahedral coordination with site symmetry 222, a unique C atom of the oxalate anion lying on a twofold axis, an O atom of the anion in a general position and a water O atom at a site with imposed twofold rotation symmetry. The Mg2+ ions are ligated by water molecules and bridged by the anions to form chains that are held together by O—H...O hydrogen bonds. The structure of the title compound has already been reported in a different space group [Lagier, Pezerat & Dubernat (1969. Rev. Chim. Miner. 6, 1081–1093; Levy, Perrotey & Visser (1971. Bull. Soc. Chim. Fr. pp. 757–761].

  10. A previously unknown oxalyl-CoA synthetase is important for oxalate catabolism in Arabidopsis

    Science.gov (United States)

    Oxalate is produced by several catabolic pathways in plants. The best characterized pathway for subsequent oxalate degradation is via oxalate oxidase, but some species, such as Arabidopsis thaliana, have no oxalate oxidase activity. Previously, an alternative pathway was proposed in which oxalyl-CoA...

  11. Diet, but not oral probiotics, effectively reduces urinary oxalate excretion and calciumoxalate supersaturation

    Science.gov (United States)

    Lieske, John C.; Tremaine, William J.; De Simone, Claudio; O’Connor, Helen M.; Li, Xujian; Bergstralh, Eric J.; Goldfarb, David S.

    2014-01-01

    We examined the effect of a controlled diet and two probiotic preparations on urinary oxalate excretion, a risk factor for calcium oxalate kidney stone formation, in patients with mild hyperoxaluria. Patients were randomized to a placebo, a probiotic, or a synbiotic preparation. This tested whether these probiotic preparations can increase oxalate metabolism in the intestine and/or decrease oxalate absorption from the gut. Patients were maintained on a controlled diet to remove the confounding variable of differing oxalate intake from food. Urinary oxalate excretion and calcium oxalate supersaturation on the controlled diet were significantly lower compared with baseline on a free-choice diet. Neither study preparation reduced urinary oxalate excretion nor calcium oxalate supersaturation. Fecal lactobacilli colony counts increased on both preparations, whereas enterococcal and yeast colony counts were increased on the synbiotic. Total urine volume and the excretion of oxalate and calcium were all strong independent determinants of urinary calcium oxalate supersaturation. Hence, dietary oxalate restriction reduced urinary oxalate excretion, but the tested probiotics did not influence urinary oxalate levels in patients on a restricted oxalate diet. However, this study suggests that dietary oxalate restriction is useful for kidney stone prevention. PMID:20736987

  12. 4-Oxo-N-phenyl-4H-chromene-2-carboxamide and of a new polymorph of 7-methoxy-4-oxo-N-p-tolyl-4H-chromene-2-carboxamide and its hemihydrate.

    Science.gov (United States)

    Reis, Joana; Gaspar, Alexandra; Borges, Fernanda; Gomes, Ligia R; Low, John Nicolson

    2013-12-15

    4-Oxo-N-phenyl-4H-chromene-2-carboxamide, C16H11NO3, crystallizes in the space group P2(1)/n and its derivative 7-methoxy-4-oxo-N-p-tolyl-4H-chromene-2-carboxamide, C18H15NO4, forms two polymorphs which crystallize in the space groups P2(1)/c and P1. The structures have an anti-rotamer conformation about the C-N bond; however, the amide O atom can be either trans- or cis-related to the O atom of the pyran ring. The latter compound also crystallizes as a hemihydrate, C18H15NO4·0.5H2O, in the space group C2/c. This compound has a similar structure to that of the unsolvated compound.

  13. Consultation document: risk management measure for benzenamine, N-phenyl-, reaction products with styrene and 2,4, 4-trimethylpentene (BNST)[Chemical Abstracts Service Registry Number (CAS RN): 68921-45-9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-10-15

    The Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-Trimethylpentene, also known as BNST, is a chemical substance that has been analysed by the Government of Canada in order to determine if the substance could generate harmful effects on the environment. The main use of BNST, according to industry information, is as an antioxidant in vehicle engine oils. The analysis concluded that BNST is persistent, bioaccumulative and may have harmful effects on aquatic organisms. In August 2009, considering the results of the examination, the Government of Canada suggested in a consultation paper to add BNST to the Prohibition of Certain Toxic Substances Regulations, 2005. The report provides elements to promote discussion and allow interested stakeholders to give their opinion and provide data regarding the addition of BNST to these regulations. 4 refs.

  14. N-Phenyl-N'-(2-chloroethyl)ureas (CEUs) as potential antineoplastic agents. Part 3: role of carbonyl groups in the covalent binding to the colchicine-binding site.

    Science.gov (United States)

    Moreau, Emmanuel; Fortin, Sébastien; Lacroix, Jacques; Patenaude, Alexandre; Rousseau, Jean L C; C-Gaudreault, René

    2008-02-01

    In the course of the development of N-phenyl-N'-(2-chloroethyl)ureas (CEUs) as potential antineoplastic agents, we investigated the effect of carbonylated substituting chains of the aromatic ring of CEU on their covalent binding to the colchicine-binding site (C-BS). In this study, we found that CEU, 5e, 5f, 8e, and 8f substituted by either a methyl ester or a methyl ketyl group at the omega-position exhibited a significant antiproliferative activity on HT-29, M21, and MCF-7 tumor cells. SDS-PAGE assays and cell cycle analysis confirmed that 5e, 5f, 8e, and 8f covalently bind to the C-BS and arrest the cell division in G(2)/M phase. Surprisingly, the presence of omega-carboxyl, omega-ethyl esters or omega-amides decreased significantly both the antiproliferative activity and the specificity toward beta-tubulin.

  15. An oxalyl-CoA dependent pathway of oxalate catabolism plays a role in regulating calcium oxalate crystal accumulation and defending against oxalate-secreting phytopathogens in Medicago truncatula

    Science.gov (United States)

    Considering the widespread occurrence of oxalate in nature and its broad impact on a host of organisms, it is surprising that so little is known about the turnover of this important acid. In plants, oxalate oxidase is the most well studied enzyme capable of degrading oxalate, but not all plants pos...

  16. Determination of urine oxalate level in rats with renal calcium oxalate calculus by high-performance liquid chromatography.

    Science.gov (United States)

    Cao, Qiu-shi; Ba, Yuan-ming; Luo, Jun-hua; Dai, Qi

    2015-02-01

    To establish a method of high-performance liquid chromatography (HPLC) for determining the urine oxalate levle in rats with renal calcium oxalate calculus. Totally 24 SPF Wistar healthy male rats were randomly divided into control group(n=12)and ethylene glycol (EG) group (n=12). Rats in EG group were administered intragastrically with 2% ammonium chloride (AC)2 ml/rat per day+1% ethylene glycol (EG), along with free access to drinking water.The control group was fed with deionized water, along with the intragastric administration of normal saline (1 ml per day). Twenty-eight days after modelling, the 24-hour urine samples were collected, and the urine oxalic acid levels were determined using HPLC and the results were compared with those of catalytic spectrophotometry using oxidation of methyl. During the HPLC, the samples were separated on Aglient 5TC-C18 (250×4.6 mm,5 Μm), eluted with mixture of methanol (0.1 mol/L) and ammonium acetate (15:85) at 1.2 ml/min, and detected at 314 nm, with the column temperature being 20 ℃. The standard curves of high and low concentrations of oxalic acid were y=5909.1x+378730, R² =0.9984 and y=7810.5x-16635, R² =0.9967,respectively. The lowest detectable concentration in this method was 5 Μg/ml. The linear high concentration range of oxalate stood at 62.50-2000.00 Μg/ml, and the linear low concentration range of oxalate stood at 6.25-100.00 Μg/ml. Its average recovery was 95.1%, and its within-day and day-to-day precisions were 3.4%-10.8% and 3.8%-9.4%. Both HPLC and catalytic spectrophotometry showed significantly higher urinary oxalic acid concentration and 24 h urine oxalate level in EG group compared with the control group [urinary oxalic acid concentration: (736.35 ± 254.52) Μg/ml vs.(51.56 ± 36.34) Μg/ml,(687.35 ± 234.53) Μg/ml vs.(50.24 ± 42.34) Μg/ml;24 h urine oxalate level: (11.23 ± 4.12)mg vs.(0.87 ± 0.45)mg,(9.89 ± 3.55)mg vs. (0.77 ± 0.65)mg; all P0.05). HPLC is a simple, rapid, and precise method

  17. 3.2.1. Synthesis, crystal and molecular structure of catena-(bis(µ1-oxalic acid-µ3-hydrogen oxalate-di-aqua-sodium(I.

    Directory of Open Access Journals (Sweden)

    Olga Kovalchukova*, Sergey Aldoshin, Andrey Utenyshev, Konstantin Bogenko, Valeriy Tkachev

    2015-07-01

    Full Text Available The crystal and molecular structure of catena-(bis(µ- oxalic acid-µ-hydrogen oxalate-di-aqua-sodium(I was detected by X-Ray analysis. The compound crystallizes in the triclinic space group P-1, with a(Å 6.2378(12; b(Å 7,1115(14; c(Å 10.489(2; α(° 94.65(3; β(° 100.12(3; γ(° 97.78(3. The sodium cation in the title compound is eight coordinated and forms a square antiprism. It is surrounded by two molecules of oxalic acid, one hydrogen oxalate anion and one water molecule. Both oxalic acid and hydrogen oxalate anion act as polydentate bridging ligands. Centrosymmetric sodium cations are bounded by hydrogen oxalate anions through a system of H bonds involving the molecules of oxalic acid. In the lattice, the 3D structure stabilized by H bonds is formed.

  18. Oxalic acid biosynthesis and oxalacetate acetylhydrolase activity in Streptomyces cattleya.

    Science.gov (United States)

    Houck, D R; Inamine, E

    1987-11-15

    In addition to producing the antibiotic thienamycin, Streptomyces cattleya accumulates large amounts of oxalic acid during the course of a fermentation. Washed cell suspensions were utilized to determine the specific incorporation of carbon-14 into oxalate from a number of labeled organic and amino acids. L-[U-14C]aspartate proved to be the best precursor, whereas only a small percentage of label from [1,5-14C]citrate was found in oxalate. Cell-free extracts catalyzed the formation of [14C]oxalate and [14C]acetate from L-[U-14C]aspartate. When L-[4-14C]aspartate was the substrate only [14C]acetate was formed. The cell-free extracts were found to contain oxalacetate acetylhydrolase (EC 3.7.1.1), the enzyme that catalyzes the hydrolysis of oxalacetate to oxalate and acetate. The enzyme is constitutive and is analogous to enzymes in fungi that produce oxalate from oxalacetate. Properties of the crude enzyme were examined.

  19. Oxalic acid biosynthesis and oxalacetate acetylhydrolase activity in Streptomyces cattleya

    Energy Technology Data Exchange (ETDEWEB)

    Houck, D.R.; Inamine, E.

    1987-11-15

    In addition to producing the antibiotic thienamycin, Streptomyces cattleya accumulates large amounts of oxalic acid during the course of a fermentation. Washed cell suspensions were utilized to determine the specific incorporation of carbon-14 into oxalate from a number of labeled organic and amino acids. L-(U-/sup 14/C)aspartate proved to be the best precursor, whereas only a small percentage of label from (1,5-/sup 14/C)citrate was found in oxalate. Cell-free extracts catalyzed the formation of (/sup 14/C)oxalate and (/sup 14/C)acetate from L-(U-/sup 14/C)aspartate. When L-(4-/sup 14/C)aspartate was the substrate only (/sup 14/C)acetate was formed. The cell-free extracts were found to contain oxalacetate acetylhydrolase, the enzyme that catalyzes the hydrolysis of oxalacetate to oxalate and acetate. The enzyme is constitutive and is analogous to enzymes in fungi that produce oxalate from oxalacetate. Properties of the crude enzyme were examined.

  20. DETERMINATION OF OXALATE ION DOPANT LEVEL IN POLYPYRROLE USING FT-IR.

    Science.gov (United States)

    Miller, Eric T; Benally, Kristal J; GreyEyes, Shawn D; McKenzie, Jason T

    A pellet method using standard addition and FT-IR was used to estimate oxalate ion doping levels in electrosynthesized polypyrrole. The method is useful for materials where removal of analyte from an insoluble material is problematic. Here, electrosynthesized oxalate doped polypyrrole is dispersed in potassium bromide. Spikes of sodium oxalate are added and the mixtures pressed into pellets. The oxalate carbonyl absorption peak is then used to quantify the amount of oxalate present in the polypyrrole. The mass fraction of oxalate dopant in polypyrrole was determined to be 0.4 ± 0.1 % and coincides with the original synthesis solution composition.

  1. Urinary supersaturation with respect to brushite in patients suffering calcium oxalate lithiasis.

    Science.gov (United States)

    Berland, Y; Boistelle, R; Olmer, M

    1990-01-01

    The urines of 23 stone-formers presenting repeated calcium oxalate lithiasis and 12 control subjects were collected at six different time periods daily. Supersaturations for calcium oxalate and brushite (DCPD) were calculated using ionic and solubility products. Urines of both groups were supersaturated for calcium oxalate but only urines of the stone-formers were supersaturated for brushite, the most simple calcium phosphate which nucleates very easily at the urinary pH. This fact suggests that the core of the calcium oxalate stone could be made of either a calcium oxalate crystallite or a brushite seed onto which hetergeneous nucleation of calcium oxalate can take place.

  2. Drug dosage protocol for calcium oxalate stone.

    Science.gov (United States)

    Marickar, Y M Fazil; Salim, Abiya

    2009-12-01

    In earlier studies, we have confirmed that in most patients with calcium oxalate stone formation, a combination of allopurinol and pyridoxine is best suited for treatment and prevention of the stone forming process. The objective of this study is to identify the most effective directed medical treatment of urinary stones. The drug dose adjustment was based on clinical, radiological, biochemical, and microscopic parameters. 444 patients with proved calcium oxalate stone disease who were getting a combination of allopurinol and pyridoxine for a minimum period of 36 months were enrolled in this prospective study. The dosage schedule of these patients was recorded. Dosage adjustment was made depending upon the various clinical, biochemical, microscopic, and radiological changes during the study period. The dosage schedules were in six categories, namely very high dose chemotherapy (VHDC), i.e. allopurinol 600 mg/day and pyridoxine 240 mg/day, high-dose chemotherapy (HDC), i.e. allopurinol 300 mg/day and pyridoxine 120 mg/day, moderate dose prophylaxis (MDP), i.e. allopurinol 200 mg/day and pyridoxine 80 mg/day, low-dose prophylaxis (LDP), i.e. allopurinol 100 mg/day and pyridoxine 40 mg/day, and very low-dose prophylaxis (VLDP), i.e. allopurinol 50 mg/day and pyridoxine 20 mg/day and intermittent VLDP, wherein the VLDP was given on alternate months and still later at longer intervals. The temporary risk was assessed at each visit and dosage adjustment was made. The effect of the intervention was assessed during the next visit. All the patients involved in the study needed dose adjustment. The following schedules were initiated: VHDC (12) 3.5%, HDC (103) 23.2%, MDP (78) 17.57%, or LDP (251) 56.53%. Patients who defaulted for more than a month were excluded from the study. During each visit for follow up, all patients were advised change over of dose depending upon the clinical situation at the time of review. Patients on VHDC were advised reduction to lower doses

  3. Surface analysis of transition metal oxalates: Damage aspects

    Energy Technology Data Exchange (ETDEWEB)

    Chenakin, S.P., E-mail: chenakin@imp.kiev.ua [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Institute of Metal Physics, Nat. Acad. Sci. of Ukraine, Akad. Vernadsky Blvd. 36, 03680 Kiev (Ukraine); Szukiewicz, R. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Barbosa, R.; Kruse, N. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Voiland School of Chemical Engineering and Bioengineering, Washington State University, 155 Wegner Hall, Pullman, WA 99164-6515 (United States)

    2016-05-15

    Highlights: • Gas evolution from the Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation is studied. • A comparative study of the damage caused by X-rays in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} is carried out. • Effect of Ar{sup +} bombardment on the structure and composition of CoC{sub 2}O{sub 4} is studied. - Abstract: The behavior of transition metal oxalates in vacuum, under X-ray irradiation and low-energy Ar{sup +} ion bombardment was studied. A comparative mass-spectrometric analysis was carried out of gas evolution from the surface of Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation. The rates of H{sub 2}O and CO{sub 2} liberation from the oxalates were found to be in an inverse correlation with the temperatures of dehydration and decomposition, respectively. X-ray photoelectron spectroscopy (XPS) was employed to study the X-ray induced damage in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} by measuring the various XP spectral characteristics and surface composition of the oxalates as a function of time of exposure to X-rays. It was shown that Cu oxalate underwent a significantly faster degradation than Ni oxalate and demonstrated a high degree of X-ray induced reduction from the Cu{sup 2+} to the Cu{sup 1+} chemical state. 500 eV Ar{sup +} sputter cleaning of CoC{sub 2}O{sub 4} for 10 min was found to cause a strong transformation of the oxalate structure which manifested itself in an appreciable alteration of the XP core-level and valence band spectra. The analysis of changes in stoichiometry and comparison of XP spectra of bombarded oxalate with respective spectra of a reference carbonate CoCO{sub 3} implied that the bombardment-induced decomposition of CoC{sub 2}O{sub 4} gave rise to the formation of CoO-like and disordered CoCO{sub 3}-like phases.

  4. Computational and experimental studies on oxalic acid imprinted polymer

    Indian Academy of Sciences (India)

    Kiran Kumar Tadi; R V Motghare

    2013-03-01

    Computational approach plays an important role to pre-evaluate the interactions between template and functional monomer, so that to choose functional monomer having stronger interactions with template during synthesis of molecularly imprinted polymers (MIPs). Hence template-monomer interactions in pre-polymerization were mainly focused. In this paper, computational chemistry was applied to screen the number of mol of functional monomer that interacts with one mol of template. Intermolecular interactions between oxalic acid and acrylamide have been investigated. The binding energies Ebind were calculated by DFT (B3LYP) level of theory with the 6−31+G(d,p) basis set. It was found that four mol of acrylamide were sufficient to interact with one mol of oxalic acid in the pre-polymerization mixture. Four possible conformations and frequency calculations were performed to locate minima. Oxalic acid specific bulk polymer was obtained by the thermal initiated free radical co-polymerization of acrylamide and ethylene glycol dimethacrylate with oxalic acid as template and acetonitrile as porogen. The synthesized MIP efficiently adsorbed oxalic acid from aqueous solutions. The binding parameters ofMIP and non-imprinted polymer (NIP) were compared by Freundlich and Langmuir adsorption isotherms.

  5. Modulation of polyepoxysuccinic acid on crystallization of calcium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanqing [School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009 (China); Tang, Yongming, E-mail: tangym@njtech.edu.cn [School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009 (China); Xu, Jinqiu; Zhang, Dongqin [School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 210009 (China); Lu, Gang [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Jing, Wenheng [College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing 210009 (China)

    2015-11-15

    The influence of polyepoxysuccinic acid (PESA) on the phase composition and crystal morphology of calcium oxalate was investigated in this paper. It was found that the presence of PESA inhibited the growth of the monoclinic calcium oxalate monohydrate (COM) crystal and promoted the nucleation of the tetragonal calcium oxalate dihydrate (COD). In addition, with the increase in PESA concentration, the aggregation of COD crystals was reduced but the particle size was increased. Under the conditions of low calcium-to-oxalate ratio and high CaOx concentration, PESA could not effectively stabilize the formation of COD. Based on molecular dynamic simulations, the adsorption of PESA on CaOx crystal faces was confirmed. - Graphical abstract: Introduction of PESA into crystallization solutions promotes the formation of calcium oxalate dehydrate and modifies the morphology of crystals. - Highlights: • PESA induces the formation of COD at low supersaturation. • Establishment of Ca-rich surface augments the adsorption of PESA. • At Ca/Ox=0.5 PESA cannot induce the formation of COD compared with Ca/Ox=2. • Interaction of PESA with COM faces is stronger than that with COD faces.

  6. The influence of scale inhibitors on calcium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Gill, J.S. [Calgon Corp., Pittsburgh, PA (United States)

    1999-11-01

    Precipitation of calcium oxalate is a common occurrence in mammalian urinary tract deposits and in various industrial processes such as paper making, brewery fermentation, sugar evaporation, and tannin concentration. Between pH 3.5 to 4.5 the driving force for calcium oxalate precipitation increases almost by three fold. It is a complicated process to predict both the nature of a deposit and at which stage of a multi-effect evaporator a particular mineral will deposit, as this depends on temperature, pH, total solids, and kinetics of mineralization. It is quite a challenge to inhibit calcium oxalate precipitation in the pH range of 4--6. Al{sup 3+} ions provide excellent threshold inhibition in this pH range and can be used to augment traditional inhibitors such as polyphosphates and polycarboxylates.

  7. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    Science.gov (United States)

    Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, François; Whittaker, James W.

    2007-01-01

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an α-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4×104 U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions. PMID:17399681

  8. Oxalic acid adsorption states on the clean Cu(110) surface

    Science.gov (United States)

    Fortuna, Sara

    2016-11-01

    Carboxylic acids are known to assume a variety of configurations on metallic surfaces. In particular oxalic acid on the Cu(110) surface has been proposed to assume a number of upright configurations. Here we explore with DFT calculations the possible structures that oxalic acid can form on copper 110 at different protonation states, with particular attention at the possibility of forming structures composed of vertically standing molecules. In its fully protonated form it is capable of anchoring itself on the surface thanks to one of its hydrogen-free oxygens. We show the monodeprotonated upright molecule with two oxygens anchoring it on the surface to be the lowest energy conformation of a single oxalic molecules on the Cu(110) surface. We further show that it is possible for this configuration to form dense hexagonally arranged patterns in the unlikely scenario in which adatoms are not involved.

  9. THORIUM OXALATE-URANYL ACETATE COUPLED PROCEDURE FOR THE SEPARATION OF RADIOACTIVE MATERIALS

    Science.gov (United States)

    Gofman, J.W.

    1959-08-11

    The recovery of fission products from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in acid and thorium oxalate is precipitated in ihe solution formed, whereby the fission products are carried on the thorium oxalate. The separated thorium oxalate precipitate is then dissolved in an aqueous oxalate solution and the solution formed is acidified, limiting ihe excess acidity to a maximum of 2 N, whereby thorium oxalate precipitates and carries lanthanum-rareearth- and alkaline-earth-metal fission products while the zirconium-fission-product remains in solution. This precipitate, too, is dissolved in an aqaeous oxalate solution at elevated temperature, and lanthanum-rare-earth ions are added to the solution whereby lanthanum-rare-earth oxalate forms and the lanthanum-rare-earth-type and alkalineearth-metal-type fission products are carried on the oxalate. The precipitate is separated from the solution.

  10. Interaction of Celestine Concentrate and Reagent Grade SrSO4 with Oxalate Solutions

    Directory of Open Access Journals (Sweden)

    Abdullah Obut

    2012-12-01

    Full Text Available The interaction of reagent grade strontium sulphate and celestine concentrate with aqueous solutions of oxalic acid, sodiumoxalate and ammonium oxalate for the production of strontium carbonate were investigated for different oxalate compound:SrSO4 moleratios and reaction times using x-ray diffraction analysis and dissolution tests. Under the same experimental conditions, it was foundthat aqueous oxalic acid and sodium oxalate solutions had no or little effect on reagent grade strontium sulphate or celestineconcentrate, but aqueous ammonium oxalate solution converted them into strontium oxalate hydrate. Strontium carbonate was obtainedat conversion ratios of 74.7% for the celestine concentrate and 84.6 % for the reagent grade strontium sulphate by the decompositionof the obtained strontium oxalate hydrate at 600 °C under air atmosphere.

  11. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

    Directory of Open Access Journals (Sweden)

    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  12. Characterization of calcium oxalate biominerals in Pereskia species (Cactaceae).

    Science.gov (United States)

    Monje, Paula V; Baran, Enrique J

    2009-01-01

    Calcium oxalate druses were isolated from the stems and leaves of six Pereskioideae family members and investigated by infrared spectroscopy, showing that in all samples the biomineral was present in the form of whewellite, CaC2O4 x H2O. As Pereskia is thought to represent the "ancestral" condition of the leafless stem-succulent cacti, these results suggest that the biomineralization of calcium oxalate in Cactaceae represents a primitive characteristic of the group and also support a close genetic relationship between Pereskia and Opuntia.

  13. Microwave studies on double rare earth oxalate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Elizabeth, Anit [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Joseph, Cyriac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Paul, Issac [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Ittyachen, M.A. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Mathew, K.T. [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)]. E-mail: ktm@cusat.ac.in; Lonappan, Anil [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India); Jacob, Joe [Microwave Imaging and Material Research Laboratory, Department of Electronics, Cochin University of Science and Technology, Kochi 682022 (India)

    2005-01-25

    Rare earth compounds are recognized for outstanding physical, magnetic and optical properties. The oxalates and molybdates have gained importance for their various properties, which find applications in electro and accusto optical devices. This paper reports the microwave dielectric studies on double rare earth oxalate crystals. Using the cavity perturbation technique dielectric parameters such as complex permittivity and conductivity at microwave frequencies is determined. Using X-ray diffraction study the crystalline nature of the samples was established. The molecular and crystal structures were identified by IR analysis.

  14. Concentration and size distribution of particulate oxalate in marine and coastal atmospheres - Implication for the increased importance of oxalate in nanometer atmospheric particles

    Science.gov (United States)

    Guo, Tianfeng; Li, Kai; Zhu, Yujiao; Gao, Huiwang; Yao, Xiaohong

    2016-10-01

    In literature, particulate oxalate has been widely studied in the total suspended particles (TSP), particles 100 nm. In this article, we measured oxalate's concentrations in size-segregated atmospheric particles down to 10 nm or 56 nm during eight campaigns performed at a semi-urban coastal site, over the marginal seas of China and from the marginal seas to the northwest Pacific Ocean (NWPO) in 2012-2015. When the sum of the oxalate's concentration in particles pollution event. Mode analysis results of particulate oxalate and the correlation between oxalate and sulfate suggested that the elevated concentrations of oxalate in PM10 were mainly related to enhanced in-cloud formation of oxalate via anthropogenic precursors. Size distribution data in the total of 136 sets of samples also showed approximately 80% of particulate oxalate's mass existing in atmospheric particles >100 nm. Consistent with previous studies, particulate oxalate in particles >100 nm was a negligible ionic component when comparing to particulate SO42- in the same size range. However, the mole ratios of oxalate/sulfate in particles 100 nm atmospheric particles such as PM2.5, PM10, TSP, etc.

  15. Determining the Structure of Oxalate Anion Using Infrared and Raman Spectroscopy Coupled with Gaussian Calculations

    Science.gov (United States)

    Peterson, Karen I.; Pullman, David P.

    2016-01-01

    A laboratory project for the upper-division physical chemistry laboratory is described, and it combines IR and Raman spectroscopies with Gaussian electronic structure calculations to determine the structure of the oxalate anion in solid alkali oxalates and in aqueous solution. The oxalate anion has two limiting structures whose vibrational spectra…

  16. Enzymatic oxalic acid regulation correlated with wood degradation in four brown-rot fungi

    Science.gov (United States)

    Anne Christine Steenkjær Hastrup; Frederick Green III; Patricia K. Lebow; Bo Jensen

    2012-01-01

    Oxalic acid is a key component in the initiation of brown-rot decay and it has been suggested that it plays multiple roles during the degradation process. Oxalic acid is accumulated to varying degrees among brown-rot fungi; however, details on active regulation are scarce. The accumulation of oxalic acid was measured in this study from wood degraded by the four brown-...

  17. Oxaloacetate hydrolase, the C-C bond lyase of oxalate secreting fungi

    NARCIS (Netherlands)

    Han, Y.; Joosten, H.J.; Niu, W.; Zhao, Z.; Mariano, P.S.; McCalman, M.; Kan, van J.; Schaap, P.J.; Dunaway-Mariano, D.

    2007-01-01

    Oxalate secretion by fungi is known to be associated with fungal pathogenesis. In addition, oxalate toxicity is a concern for the commercial application of fungi in the food and drug industries. Although oxalate is generated through several different biochemical pathways, oxaloacetate acetylhydrolas

  18. Clinical evaluation of ferric oxalate in relieving dentine hypersensitivity.

    Science.gov (United States)

    Gillam, D G; Newman, H N; Davies, E H; Bulman, J S; Troullos, E S; Curro, F A

    2004-03-01

    Previous in vitro permeability and scanning electron microscopic (SEM) studies have demonstrated the effectiveness of the oxalate ion in dentine permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, split mouth 4-week clinical study, therefore was to determine whether a 1-min application of ferric oxalate (Sensodyne Sealant) on exposed root dentine was effective in reducing dentine hypersensitivity (DH). Thirteen subjects [8F:5M, mean age 46.2 (s.d. 4.15) years] completed the study. The subjective response was evaluated by tactile, thermal and evaporative methods of assessment. Data were collected at baseline and post-application at +5 min and 4 weeks. Analysis was based on paired t-test (P=0.05) and Wilcoxon-Mann-Whitney tests. No statistically significant differences were noted between ferric oxalate and placebo preparations at +5 min and 4 weeks for any of the test stimuli. There was, however, a clear trend towards immediate reduction (+5 min) in DH reverting back to baseline values at 4 weeks with the exception of the Biomat Thermal Probe mean values, which maintained the reductions in DH compared with placebo. The results of the present study demonstrated that a 1-min application of ferric oxalate is both rapid and effective in reducing DH although its long-term effectiveness still needs to be determined.

  19. In vivo Drosophilia genetic model for calcium oxalate nephrolithiasis.

    Science.gov (United States)

    Hirata, Taku; Cabrero, Pablo; Berkholz, Donald S; Bondeson, Daniel P; Ritman, Erik L; Thompson, James R; Dow, Julian A T; Romero, Michael F

    2012-12-01

    Nephrolithiasis is a major public health problem with a complex and varied etiology. Most stones are composed of calcium oxalate (CaOx), with dietary excess a risk factor. Because of complexity of mammalian system, the details of stone formation remain to be understood. Here we have developed a nephrolithiasis model using the genetic model Drosophila melanogaster, which has a simple, transparent kidney tubule. Drosophilia reliably develops CaOx stones upon dietary oxalate supplementation, and the nucleation and growth of microliths can be viewed in real time. The Slc26 anion transporter dPrestin (Slc26a5/6) is strongly expressed in Drosophilia kidney, and biophysical analysis shows that it is a potent oxalate transporter. When dPrestin is knocked down by RNAi in fly kidney, formation of microliths is reduced, identifying dPrestin as a key player in oxalate excretion. CaOx stone formation is an ancient conserved process across >400 My of divergent evolution (fly and human), and from this study we can conclude that the fly is a good genetic model of nephrolithiasis.

  20. Oxalate Mass Balance During Chemical Cleaning in Tank 5F

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-07-08

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 5F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate.

  1. Phase transition in L-alaninium oxalate by photoacoustics

    Indian Academy of Sciences (India)

    M Sivabarathy; S Natarajan; S K Ramakrishnan; K Ramachandran

    2004-10-01

    Phase transition in L-alaninium oxalate is studied by using TG, DTA and photoacoustic spectroscopy. A sharp transition at 378 K by photoacoustics is observed whereas at the same temperature the endothermic energy change observed by TG and DTA is not very sharp. This is discussed in detail with reference to the other known data for the organic crystals.

  2. Production of battery grade materials via an oxalate method

    Energy Technology Data Exchange (ETDEWEB)

    Belharouak, Ilias; Amine, Khalil

    2016-05-17

    An active electrode material for electrochemical devices such as lithium ion batteries includes a lithium transition metal oxide which is free of sodium and sulfur contaminants. The lithium transition metal oxide is prepared by calcining a mixture of a lithium precursor and a transition metal oxalate. Electrochemical devices use such active electrodes.

  3. Crystal growth and morphology of calcium oxalates and carbonates

    NARCIS (Netherlands)

    Heijnen, W.M.M.

    1986-01-01

    The main purpose of the research described in this thesis is to establish a relationship between the crystal structure and morphology of calcium oxalate and calcium carbonate crystals grown from aqueous solutions. Starting point is the PBC (Periodic Bond Chain) theory formulated by Hartman and Perdo

  4. Transcellular oxalate and Cl- absorption in mouse intestine is mediated by the DRA anion exchanger Slc26a3, and DRA deletion decreases urinary oxalate.

    Science.gov (United States)

    Freel, Robert W; Whittamore, Jonathan M; Hatch, Marguerite

    2013-10-01

    Active transcellular oxalate transport in the mammalian intestine contributes to the homeostasis of this important lithogenic anion. Several members of the Slc26a gene family of anion exchangers have a measurable oxalate affinity and are expressed along the gut, apically and basolaterally. Mouse Slc26a6 (PAT1) targets to the apical membrane of enterocytes in the small intestine, and its deletion results in net oxalate absorption and hyperoxaluria. Apical exchangers of the Slc26a family that mediate oxalate absorption have not been established, yet the Slc26a3 [downregulated in adenoma (DRA)] protein is a candidate mediator of oxalate uptake. We evaluated the role of DRA in intestinal oxalate and Cl(-) transport by comparing unidirectional and net ion fluxes across short-circuited segments of small (ileum) and large (cecum and distal colon) intestine from wild-type (WT) and DRA knockout (KO) mice. In WT mice, all segments demonstrated net oxalate and Cl(-) absorption to varying degrees. In KO mice, however, all segments exhibited net anion secretion, which was consistently, and solely, due to a significant reduction in the absorptive unidirectional fluxes. In KO mice, daily urinary oxalate excretion was reduced 66% compared with that in WT mice, while urinary creatinine excretion was unchanged. We conclude that DRA mediates a predominance of the apical uptake of oxalate and Cl(-) absorbed in the small and large intestine of mice under short-circuit conditions. The large reductions in urinary oxalate excretion underscore the importance of transcellular intestinal oxalate absorption, in general, and, more specifically, the importance of the DRA exchanger in oxalate homeostasis.

  5. The effects of oxalate-containing products on the exposed dentine surface: an SEM investigation.

    Science.gov (United States)

    Gillam, D G; Mordan, N J; Sinodinou, A D; Tang, J Y; Knowles, J C; Gibson, I R

    2001-11-01

    In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.

  6. Plasma biochemistry and urinalysis variables of koalas (Phascolarctos cinereus) with and without oxalate nephrosis.

    Science.gov (United States)

    Speight, K Natasha; Haynes, Julie I; Boardman, Wayne; Breed, William G; Taggart, David A; Rich, Brian; Woolford, Lucy

    2014-06-01

    Oxalate nephrosis is a highly prevalent disease in the Mount Lofty Ranges koala population in South Australia, but associated clinicopathologic findings remain undescribed. The aims of this study were to determine plasma biochemical and urinalysis variables, particularly for renal function and urinary crystal morphology and composition, in koalas with oxalate nephrosis. Blood and urine samples from Mount Lofty Ranges koalas with oxalate nephrosis were compared with those unaffected by renal oxalate crystal deposition from Mount Lofty and Kangaroo Island, South Australia and Moggill, Queensland. Plasma and urine biochemistry variables were analyzed using a Cobas Bio analyzer, and urinary oxalate by high-performance liquid chromatography. Urinary crystal composition was determined by infrared spectroscopy and energy dispersive X-ray analysis. Azotemia (urea > 6.6 mmol/L, creatinine > 150 μmol/L) was found in 93% of koalas with oxalate nephrosis (n = 15). All azotemic animals had renal insufficiency (urine specific gravity [USG] Koalas with oxalate nephrosis were hyperoxaluric compared with Queensland koalas (P koalas with oxalate nephrosis had atypical morphology and were composed of calcium oxalate. Mount Lofty Ranges koalas unaffected by renal oxalate crystal deposition had renal insufficiency (43%), although only 14% had USG koalas were hyperoxaluric compared with Queensland koalas (P Koalas with oxalate nephrosis from the Mount Lofty Ranges had renal insufficiency, hyperoxaluria, and pathognomonic urinary crystals. The findings of this study will aid veterinary diagnosis of this disease. © 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology.

  7. Real-Time kinetic studies of Bacillus subtilis oxalate decarboxylase and Ceriporiopsis subvermispora oxalate oxidase using a luminescent oxygen sensor

    Directory of Open Access Journals (Sweden)

    Laura Molina

    2014-12-01

    Full Text Available Oxalate decarboxylase (OxDC, an enzyme of the bicupinsuperfamily, catalyzes the decomposition of oxalate into carbondioxide and formate at an optimal pH of 4.3 in the presence ofoxygen. However, about 0.2% of all reactions occur through anoxidase mechanism that consumes oxygen while producing twoequivalents of carbon dioxide and one equivalent of hydrogenperoxide. The kinetics of oxidase activity were studied bymeasuring the consumption of dissolved oxygen over time using a luminescent oxygen sensor. We describe the implementation of and improvements to the oxygen consumption assay. The oxidase activity of wild type OxDC was compared to that of the T165V OxDC mutant, which contains an impaired flexible loop covering the active site. The effects of various carboxylic acid-based buffers on the rate of oxidase activity were also studied. These results were compared to the oxidase activity of oxalate oxidase (OxOx, a similar bicupin enzyme that only carries out oxalate oxidation. Thetemperature dependence of oxidase activity was analyzed, andpreliminary results offer an estimate for the overall activationenergy of the oxidase reaction within OxDC. The data reported here thus provide insights into the mechanism of the oxidase activity of OxDC.

  8. Crystal and Molecular Structure of N-Phenyl 1-Methoxycarbonylmethyl-3-benzyl-1,2,3,4- tetrahydro-4-oxo-1,3,2-benzodiazaphosphorin- 2-thiocarboxamide 2-Oxide

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The crystal structure of the title compound N-phenyl 1-methoxycarbonyl methy-3-benzyl-1,2,3,4-tetrahydro-4-oxo-1,3,2-benzodiazaphosphorin-2-thiocarboxamide 2-oxide, C24H22N3O4PS (Mr = 479.50), was determined by single-crystal X-ray diffraction at 299±1 K. It crystallizes in the triclinic system, space group P _ 1 with a = 10.555(2), b = 11.733(2), c = 12.191(2) ?, a = 60.50(3),β= 62.10(3), g = 75.09(3)°, V = 1161(1) ?3, Z = 2, Dx =1.372 g·cm-3, l = 0.71073 ?, m = 0.2351 mm-1 and F(000) = 500. The structure was solved by direct methods. The final R factor is 0.046 and Rw is 0.061 for 3246 observed reflections with I ≥3s(I). The results presented herein indicate that in the phosphorus-containing bicyclic moiety, atoms C(21), C(22), C(23), C(24), C(25), C(26), C(27), N(3) and N(2) are nearly coplanar. Moreover, the proximate thiocarbonyl and phosphoryl groups are nearly coplanar, and the P=O bond is trans-parallel to the C=S bond. Molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two hydrogen bonds which connected the nitrogen atom of one molecule to the phosphoryl oxygen atom of the other forming a ten-membered ring.

  9. Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2014-01-01

    Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

  10. Dependence of bisphenol A photodegradation on the initial concentration of oxalate in the lepidocrocite-oxalate complex system

    Institute of Scientific and Technical Information of China (English)

    DONG Jun; LI Fang-bai; LAN Chong-yu; LIU Cheng-shuai; LI Xiao-min; LUAN Tian-gang

    2006-01-01

    To understand the degradation of endocrine disrupting chemicals (EDCs) in natural environment with existence of iron oxides and carboxylic acids, the dependence ofbisphenol A (BPA) photodegradation on the initial concentration ofoxalate (Cox) in lepidocrocite (γ-FeOOH) aqueous suspension was investigated under both UV and visible lights in this study. Lepidocrocite powder was home-prepared by a hydrothermal process. It was found that BPA degradation was promoted greatly in the presence of oxalate owing to the formation of lepidocrocite-oxalate complex. And there was an optimal Cox, which was 2.0 and 2.4 mmol/L, under UV and visible lights, respectively. The first-order kinetic constant, k value increased 38 times from 0.17 × 10-2 min-1 in the absence of oxalate to 6.39 × 10-2 min-1 in the presence ofoxalate with an optimal Cox (2.0 mmol/L) under UV irradiation, and almost 306 times from 0.02 × 10-2 min-1 in the absence ofoxalate to 6.11 × 10-2 min-1 in the presence of oxalate with an optimal Cox (2.4 mmol/L) under visible irradiation. The BPA degradation rate increased and the first-order kinetic constants decreased with the increase in BPA initial concentration. The dependence of the variation of pH value, total-Fe and Fe2+ during the photoreaction on Cox was also investigated.The pH value increased obviously with the reaction time. Total-Fe increased dramatically at the first 5 min and then decreased quickly under UV irradiation and slowly under visible irradiation. The initial concentration of oxalate is a main factor to affect BPA photodegradation in aqueous suspension under both UV and visible lights.

  11. (S-N-Phenyl-tert-butanesulfinamide

    Directory of Open Access Journals (Sweden)

    Xiaofei Sun

    2012-06-01

    Full Text Available The asymmetric unit of the title compound, C10H15NOS, contains two independent molecules with similar conformations. In the crystal, molecules are linked in a head-to-tail fashion by N—H...O hydrogen bonds into chains running along the b axis. The absolute configuration was assigned on the basis of known chirality of the parent compound.

  12. 4-Nitro-N-phenyl-benzene-sulfonamide.

    Science.gov (United States)

    Chaithanya, U; Foro, Sabine; Gowda, B Thimme

    2012-10-01

    In the title compound, C(12)H(10)N(2)O(4)S, the dihedral angle between the aromatic rings is 36.19 (18)°. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into C(4) chains running along the a axis.

  13. 2-Nitro-N-phenyl-benzene-sulfonamide.

    Science.gov (United States)

    Chaithanya, U; Foro, Sabine; Gowda, B Thimme

    2012-09-01

    In the title compound, C(12)H(10)N(2)O(4)S, the conformation of the N-H bond in the -SO(2)-NH- fragment is syn to the ortho-nitro group in the sulfonyl-benzene ring. The mol-ecule is twisted at the S-N bond, the C-N-S-C torsion angle being -72.83 (15)°. The dihedral angle between the benzene rings is 59.55 (7)°. The amide H atom and the nitro group O atom form an intra-molecular hydrogen bond, generating an S(7) motif. In the crystal, C-H⋯O hydrogen-bond inter-actions link the mol-ecules into S(2) (2)(10) networks.

  14. Oxalate-Degrading Capacities of Gastrointestinal Lactic Acid Bacteria and Urinary Tract Stone Formation

    Directory of Open Access Journals (Sweden)

    Mohammad Kargar

    2013-10-01

    Full Text Available Background: Calcium oxalate is one the most significant causes of human kidney stones. Increasing oxalate uptake results in increased urinary oxalate. Elevated urinary oxalate is one the most important causes of kidney stone formation. This study aims to evaluate oxalate-degrading capacity of lactic acid bacteria and its impact on incidence of kidney stone.Materials and Methods: This case-control study was conducted on serum, urinary, and fecal samples. The research population included a total of 200 subjects divided in two equal groups. They were selected from the patients with urinary tract stones, visiting urologist, and also normal people. The level of calcium, oxalate, and citrate in the urinary samples, parathyroid and calcium in the serum samples, and degrading activity of fecal lactobacillus strains of all the subjects were evaluated. Then, data analysis was carried out using SPSS-11.5, χ2 test, Fisher’s exact test, and analysis of variance. Results: The results revealed that the patients had higher urinary level of oxalate and calcium, as well as higher serum level of parathyroid hormone than normal people. In contrast, urinary level of citrate was higher in normal people. In addition, there was a significant difference between the oxalate-degrading capacities of lactobacillus isolated from the patients and their normal peers.Conclusion: Reduction of digestive lactobacillus-related oxalate-degrading capacity and increased serum level of parathyroid hormone can cause elevated urinary level of oxalate and calcium in people with kidney stone.

  15. Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.

    Science.gov (United States)

    Studenroth, Sabine; Huber, Stefan G; Kotte, Karsten; Schöler, Heinz F

    2013-02-05

    Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.

  16. Preparation, spectral and thermal studies of neodymium zirconyl oxalate hexahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, V.B.; Mehrotra, P.N. (Roorkee Univ. (India). Dept. of Chemistry)

    Neodymium zirconyl oxalate (NdZrOX) is prepared and characterized by chemical analysis and IR spectral studies. Its thermal decomposition was investigated using DTA, TG, DTG, x-ray diffraction and IR spectroscopy. Based on thermogravimetry and isothermal studies a probable mechanism for the decomposition is proposed. The decomposition proceeds mainly through three stages: dehydration between RT-413 K; decomposition of oxalate between 413-943 K; and decomposition of the carbonate between 1028-1235 K to give a mixed oxide. The IR spectra and x-ray diffraction studies are made for identification of the intermediates. X-ray diffraction studies of the end product indicates that it belongs to cubic crystal system.

  17. Growth of strontium oxalate crystals in agar–agar gel

    Indian Academy of Sciences (India)

    P V Dalal; K B Saraf

    2011-04-01

    Single crystals of strontium oxalate have been grown by using strontium chloride and oxalic acid in agar–agar gel media at ambient temperature. Different methods for growing crystals were adopted. The optimum conditions were employed in each method by varying concentration of gel and reactants, and gel setting time etc. Transparent prismatic bi-pyramidal platy-shaped and spherulite crystals were obtained in various methods. The grown crystals were characterized with the help of FT–IR studies and monoclinic system of crystals were supported with lattice parameters = 9.67628 Å, = 6.7175 Å, = 8.6812 Å, = 113.566°, and = 521.84 Å3 calculated from X-ray diffractogram.

  18. Bis(l-serinium oxalate dihydrate: polymorph II

    Directory of Open Access Journals (Sweden)

    Marta Kulik

    2013-11-01

    Full Text Available A corrected and improved structure of the polymorph II of 2C3H8NO3+·C2O42−·2H2O, based on single-crystal data, is presented. The structure is refined with anisotropic displacement parameters for all non-H atoms and all H atoms are located. Due to the charged moieties, the structure is classified as a molecular salt. Intermolecular O—H...O−, O—H...O and N+—H...O−hydrogen bonds link the components of the structure. The l-serinium cations and oxalate anions form a network of channels in [100] direction, filled with the water molecules of crystallization. The dihedral angle between the CO2 units of the oxalate dianion is 10.2 (3°

  19. Equilibrium studies of oxalate and aluminum containing solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hay, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); King, W. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, D. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-01

    The Savannah River National Laboratory (SRNL) was tasked to develop data on the solubility and conditions leading to precipitation of sodium oxalate, sodium nitrate, Bayerite (a polymorph of gibbsite, Al(OH)3), and sodium aluminosilicate solids recently found in the Modular Caustic Side Solvent Extraction Unit (MCU). The data generated will be used to improve the OLI Systems thermodynamic database for these compounds allowing better prediction of solids formation by the modeling software in the future.

  20. Neutral tripodal receptors towards efficient trapping of oxalate

    Indian Academy of Sciences (India)

    Ranjan Dutta; Bijit Chowdhury; Purnandhu Bose; Pradyut Ghosh

    2014-09-01

    Tris(2-aminoethyl)amine (TREN) based pentafluorophenyl urea and 4-cyanophenyl thiourea receptors have shown encapsulation of oxalate (C2O$^{2−}_{4}$) in semi-aqueous environment. A single crystal X-ray study shows trapping of planar conformer of C2O$^{2−}_{4}$ in both the cases. Further solution state binding of C2O$^{2−}_{4}$ is probed by 1H-NMR titration study in semi-aqueous solvent.

  1. Conductivity of Oxalic Acid in Aqueous Solution at Low Concentration

    Institute of Scientific and Technical Information of China (English)

    倪良; 韩世钧

    2005-01-01

    Oxalic acid is a weak and unsymmetrical bi-basic acid. There exist dissociation and association equilibria among the species in aqueous solution. The molar conductivity of the solution is the sum of the ionic contributions.Based on this idea, a new prediction equation of ionic conductivity was proposed at low concentration. The molar conductivities of the solution and its relevant ions were calculated respectively. The results obtained were in good agreement with those from experiments and the Quint-Viallard equation.

  2. Hafnium(IV) complexation with oxalate at variable temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Friend, Mitchell T.; Wall, Nathalie A. [Washington State Univ., Pullmanm, WA (United States). Dept. of Chemistry

    2017-08-01

    Appropriate management of fission products in the reprocessing of spent nuclear fuel (SNF) is crucial in developing advanced reprocessing schemes. The addition of aqueous phase complexing agents can prevent the co-extraction of these fission products. A solvent extraction technique was used to study the complexation of Hf(IV) - an analog to fission product Zr(IV) - with oxalate at 15, 25, and 35 C in 1 M HClO{sub 4} utilizing a {sup 175+181}Hf radiotracer. The mechanism of the solvent extraction system of 10{sup -5} M Hf(IV) in 1 M HClO{sub 4} to thenoyltrifluoroacetone (TTA) in toluene demonstrated a 4{sup th}-power dependence in both TTA and H{sup +}, with Hf(TTA){sub 4} the only extractable species. The equilibrium constant for the extraction of Hf(TTA){sub 4} was determined to be log K{sub ex}=7.67±0.07 (25±1 C, 1 M HClO{sub 4}). The addition of oxalate to the aqueous phase decreased the distribution ratio, indicating aqueous Hf(IV)-oxalate complex formation. Polynomial fits to the distribution data identified the formation of Hf(ox){sup 2+} and Hf(ox){sub 2(aq)} and their stability constants were measured at 15, 25, and 35 C in 1 M HClO{sub 4}. van't Hoff analysis was used to calculate Δ{sub r}G, Δ{sub r}H, and Δ{sub r}S for these species. Stability constants were observed to increase at higher temperature, an indication that Hf(IV)-oxalate complexation is endothermic and driven by entropy.

  3. Characterization of calcium oxalates generated as biominerals in cacti.

    Science.gov (United States)

    Monje, Paula V; Baran, Enrique J

    2002-02-01

    The chemical composition and morphology of solid material isolated from various Cactaceae species have been analyzed. All of the tested specimens deposited high-purity calcium oxalate crystals in their succulent modified stems. These deposits occurred most frequently as round-shaped druses that sometimes coexist with abundant crystal sand in the tissue. The biominerals were identified either as CaC(2)O(4).2H(2)O (weddellite) or as CaC(2)O(4).H(2)O (whewellite). Seven different species from the Opuntioideae subfamily showed the presence of whewellite, and an equal number of species from the Cereoideae subfamily showed the deposition of weddellite. The chemical nature of these deposits was assessed by infrared spectroscopy. The crystal morphology of the crystals was visualized by both conventional light and scanning electron microscopy. Weddellite druses were made up of tetragonal crystallites, whereas those from whewellite were most often recognized by their acute points and general star-like shape. These studies clearly demonstrated that members from the main traditional subfamilies of the Cactaceae family could synthesize different chemical forms of calcium oxalate, suggesting a definite but different genetic control. The direct relationship established between a given Cactaceae species and a definite calcium oxalate biomineral seems to be a useful tool for plant identification and chemotaxonomy.

  4. Characterization of Calcium Oxalates Generated as Biominerals in Cacti1

    Science.gov (United States)

    Monje, Paula V.; Baran, Enrique J.

    2002-01-01

    The chemical composition and morphology of solid material isolated from various Cactaceae species have been analyzed. All of the tested specimens deposited high-purity calcium oxalate crystals in their succulent modified stems. These deposits occurred most frequently as round-shaped druses that sometimes coexist with abundant crystal sand in the tissue. The biominerals were identified either as CaC2O4.2H2O (weddellite) or as CaC2O4.H2O (whewellite). Seven different species from the Opuntioideae subfamily showed the presence of whewellite, and an equal number of species from the Cereoideae subfamily showed the deposition of weddellite. The chemical nature of these deposits was assessed by infrared spectroscopy. The crystal morphology of the crystals was visualized by both conventional light and scanning electron microscopy. Weddellite druses were made up of tetragonal crystallites, whereas those from whewellite were most often recognized by their acute points and general star-like shape. These studies clearly demonstrated that members from the main traditional subfamilies of the Cactaceae family could synthesize different chemical forms of calcium oxalate, suggesting a definite but different genetic control. The direct relationship established between a given Cactaceae species and a definite calcium oxalate biomineral seems to be a useful tool for plant identification and chemotaxonomy. PMID:11842173

  5. Inhibition of oxalate nephrolithiasis with Ammi visnaga (AI-Khillah).

    Science.gov (United States)

    Khan, Z A; Assiri, A M; Al-Afghani, H M; Maghrabi, T M

    2001-01-01

    We investigated the effect of Ammi visnaga seeds on experimentally - induced kidney stones - in male Wistar albino rats. Oxalate nephrolithiasis was experimentally induced by 3% glycolic acid (added in their diet) given for the period of four weeks. A highly significant amount of deposits were found in the kidneys, which were analyzed quantitatively. These deposits were mainly of calcium oxalate in composition. Daily oral (gavage) treatment with Ammi visnaga (500 mg/kg) highly reduced the incidence of nephrolithiasis (calcium oxalate deposition in the kidneys). Ammi visnaga seeds extract showed highly potent diuretic activity. The reduction in body weight, increase in kidneys weight, increase in water intake, decrease in urine output found in glycolic acid control group were prevented to various extent on Ammi visnaga treatment; and the values became to insignificant difference with control group. The changes in weights of liver, heart and lungs of the three groups were insignificant. Uraemia and hyperbilirubinaemia observed in glycolic acid control group were found to be ameliorated by Ammi visnaga seed extract treatment.

  6. Acute oxalate poisoning attributable to ingestion of curly dock (Rumex crispus) in sheep.

    Science.gov (United States)

    Panciera, R J; Martin, T; Burrows, G E; Taylor, D S; Rice, L E

    1990-06-15

    Ten of 100 mature ewes were afflicted with acute oxalate toxicosis within 40 hours after being temporarily penned in a lot that contained considerable growing Rumex crispus (curly dock). Clinical signs of toxicosis included excess salivation, tremors, ataxia, and recumbency. Affected ewes were markedly hypocalcemic and azotemic. Oxalate crystals were not observed in urine. Gross postmortem lesions were minimal and nondiagnostic in 2 ewes that died peracutely, but perirenal edema and renal tubular degeneration were clearly observable in ewes euthanatized on the third day of toxicosis. Diagnosis of oxalate toxicosis was confirmed by histopathologic findings. Samples of Rumex spp contained 6.6 to 11.1% oxalic acid on a dry-weight basis, a concentration comparable with that in other oxalate-containing plants that have caused acute oxalate toxicosis.

  7. A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

    Directory of Open Access Journals (Sweden)

    Yanfang Xu

    2016-01-01

    Full Text Available A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from 1.94×109 to 4.89×109 cm−2 were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

  8. Determining the Biochemical Properties of the Oxalate Biosynthetic Component (Obc)1 from Burkholderia mallei

    OpenAIRE

    Lambert, Peter M.; Nakata, Paul A.

    2016-01-01

    Oxalic acid is produced by a variety of organisms ranging from simple microbes to complex animals. This acid has been proposed to fulfill various physiological and pathological functions which vary between organisms. In bacteria from the Burkholderia genus, oxalate secretion has been shown to be quorum sensing dependent and to support pathogenicity and cell viability. In light of the critical roles of oxalate in Burkholderia as well as other organisms, it is surprising that our understanding ...

  9. Determination of common anions in oxalate by ion chromatography coupled with UV photolysis pretreatment

    Institute of Scientific and Technical Information of China (English)

    Sheng Lin Cao; Ming Li Ye; Wei De Lv; Guang Wen Pan; Ting Ting Zhang; Zhong Yang Hu; Li Na Liang; Yan Zhu

    2012-01-01

    A new and simple method was developed to determine anions in oxalate of analytical reagent grade.After UV photolysis with optimal 1% H2O2 in 10,000 mg/L oxalate in the fabricated photoreactor,sample was directly injected into IC system.Satisfactory linearity,detections limits,good repeatability and spiked recovery were obtained.The method was successfully applied to determine anions in two commercial oxalate samples.

  10. Determination of residues in honey after treatments with formic and oxalic acid under field conditions

    OpenAIRE

    Bogdanov, Stefan; Charrière, Jean-Daniel; IMDORF, Anton; KILCHENMANN, Verena; Fluri, Peter

    2002-01-01

    International audience; Formic acid and oxalic acid field trials for control of Varroa destructor were carried out in autumn according to the Swiss prescriptions during three successive years in different apiaries in Switzerland. The following parameters were determined in honey that was harvested the year after treatment: formic acid, oxalic acid and free acidity. The following range of values were found in honeys of untreated colonies: formic acid, from 17 to 284 mg/kg, n = 34; oxalic acid,...

  11. Acute Oxalate Nephropathy Associated with Orlistat: A Case Report with a Review of the Literature

    OpenAIRE

    2013-01-01

    Orlistat is a gastrointestinal lipase inhibitor used for weight reduction in obese individuals. Enteric hyperoxaluria caused by orlistat leads to oxalate absorption. Acute oxalate nephropathy is a rare complication of treatment with orlistat. Herein we report a patient presenting with acute renal failure which improved minimal with intravenous hydration. She was found to have oxalate crystals on renal biopsy. Patient admitted orlistat use over the counter for weight reduction on further quest...

  12. The effects of oxalate treatment on the smear layer of ground surfaces of human dentine.

    Science.gov (United States)

    Pashley, D H; Galloway, S E

    1985-01-01

    The layer was evaluated by scanning electron microscopy and by measurement of hydraulic conductance before and after 2-min topical treatment with potassium chloride, neutral potassium oxalate, half-neutralized oxalic acid or both neutral and acidic oxalates. The treated smear layers were then re-evaluated microscopically and functionally both before and after acid challenge. The layers treated with KCl were not altered either microscopically or functionally and were susceptible to acid etching. Dentine surfaces treated with either oxalate solutions became less permeable and were acid-resistant.

  13. A human strain of Oxalobacter (HC-1) promotes enteric oxalate secretion in the small intestine of mice and reduces urinary oxalate excretion.

    Science.gov (United States)

    Hatch, Marguerite; Freel, Robert W

    2013-10-01

    Enteric oxalate secretion that correlated with reductions in urinary oxalate excretion was previously reported in a mouse model of primary hyperoxaluria, and in wild type (WT) mice colonized with a wild rat strain (OXWR) of Oxalobacter (Am J Physiol 300:G461–G469, 2010). Since a human strain of the bacterium is more likely to be clinically used as a probiotic therapeutic, we tested the effects of HC-1 in WT. Following artificial colonization of WT mice with HC-1, the bacteria were confirmed to be present in the large intestine and, unexpectedly, detected in the small intestine for varying periods of time. The main objective of the present study was to determine whether the presence of HC-1 promoted intestinal secretion in the more proximal segments of the gastrointestinal tract. In addition, we determined whether HC-1 colonization led to reductions in urinary oxalate excretion in these mice. The results show that the human Oxalobacter strain promotes a robust net secretion of oxalate in the distal ileum as well as in the caecum and distal colon and these changes in transport correlate with the beneficial effect of reducing renal excretion of oxalate. We conclude that OXWR effects on intestinal oxalate transport and oxalate homeostasis are not unique to the wild rat strain and that, mechanistically, HC-1 has significant potential for use as a probiotic treatment for hyperoxaluria especially if it is also targeted to the upper and lower gastrointestinal tract.

  14. Metal complexation inhibits the effect of oxalic acid in aerosols as cloud condensation nuclei (CCN

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2010-11-01

    Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to cancel the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play a key role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is one of the major components of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan with fractionation based on particle size using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid can act as CCN because of its hygroscopic properties, while metal complexes are not hygroscopic, and so cannot be CCN. Based on the concentration of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not act as CCN in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is possible that the cooling effect of organic aerosols assumed in various climate modeling studies is overestimated because of the lack of information on metal oxalate complexes in aerosols.

  15. Gadolinium oxalate derivatives with enhanced magnetocaloric effect via ionothermal synthesis.

    Science.gov (United States)

    Meng, Yan; Chen, Yan-Cong; Zhang, Ze-Min; Lin, Zhuo-Jia; Tong, Ming-Liang

    2014-09-02

    Two new oxalate-bridged Gd(III) coordination polymers, namely, (choline)[Gd(C2O4)(H2O)3Cl]Cl·H2O (1) and [Gd(C2O4)(H2O)3Cl] (2), were first obtained ionothermally by using a deep eutectic solvent (DES). The magnetic studies and heat capacity measurements reveal that the two-dimensional Gd(III)-based coordination polymer of 2 has the higher magnetic density and exhibits a larger cryogenic magnetocaloric effect (MCE) (ΔS(m) = 48 J kg(-1) K(-1) for ΔH = 7 T at 2.2 K).

  16. Development of Endoplasmic Reticulum Stress during Experimental Oxalate Nephrolithiasis.

    Science.gov (United States)

    Motin, Yu G; Lepilov, A V; Bgatova, N P; Zharikov, A Yu; Motina, N V; Lapii, G A; Lushnikova, E L; Nepomnyashchikh, L M

    2016-01-01

    Morphological and ultrastructural study of the kidney was performed in rats with oxalate nephrolithiasis. Specific features of endoplasmic reticulum stress were evaluated during nephrolithiasis and treatment with α-tocopherol. We observed the signs of endoplasmic reticulum stress with activation of proapoptotic pathways and injury to the cell lining in nephron tubules and collecting ducts. Ultrastructural changes were found in the organelles, nuclei, and cell membranes of epitheliocytes. A relationship was revealed between endoplasmic reticulum stress and oxidative damage, which developed at the early state of lithogenesis.

  17. Interactions in Calcium Oxalate Hydrate/Surfactant Systems.

    Science.gov (United States)

    Sikiric; Filipovic-Vincekovic; Babic-Ivancić Vdović Füredi-Milhofer

    1999-04-15

    Phase transformation of calcium oxalate dihydrate (COD) into the thermodynamically stable monohydrate (COM) in anionic (sodium dodecyl sulfate (SDS)) and cationic (dodecylammonium chloride) surfactant solutions has been studied. Both surfactants inhibit, but do not stop transformation from COD to COM due to their preferential adsorption at different crystal faces. SDS acts as a stronger transformation inhibitor. The general shape of adsorption isotherms of both surfactants at the solid/liquid interface is of two-plateau-type, but differences in the adsorption behavior exist. They originate from different ionic and molecular structures of crystal surfaces and interactions between surfactant headgroups and solid surface. Copyright 1999 Academic Press.

  18. The effect of antioxidant concentration of N-isopropyl-N-phenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline and mixing time of physical properties, thermal properties, mechanical properties and microstructure on natural rubber compound

    Science.gov (United States)

    Budiarto

    2017-03-01

    Study the influence of high concentrations of antioxidants N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and the mixing time of the vulcanization physical properties, thermal properties, mechanical properties and structure micro on natural rubber compound has been done. The purpose of this study is to compare the effect of anti-oxidants types IPPD and TMQ and mixing time of vulcanization of the physical properties, mechanical properties, microstructure and elemental composition of the synthesis of natural rubber compound. Processes of vulcanization with variations in the concentration of antioxidant IPPD and TMQ: 2, 3, and 4 grams and mixing time: 20, 30, and 40 minutes. Analysis characterization of physical properties and mechanical properties of natural rubber compound showed that the maturity value 0,499Nm (TMQ) and 0.489 Nm (IPPD), Mooney viscosity value of 26.7 (TMQ) and 20.8 (IPPD), the value of the elongation at break 583.75 % (IPPD), and 552.63% (TMQ) as well as the value of tensile strength of 28.108 M.Pa (TMQ), and 27.986 M.Pa (IPPD). Analysis of thermal properties of natural rubber compound antioxidant IPPD with DTA shows there are three endothermic peak on the curve that is temperature 405°C, 550°C and 660°C and tested by TGA showed that the curve of the total reduction in the sample are 81.745% and compound rubber antioxidant TMQ with the analysis of DTA also contained 3 endothermic peak at a temperature 397,21°C, 514,02°C, and 610,27°C and TGA analysis shows the curve of the total sample of 82.356% reduction. Gsi fun group analysis rubber-antioxidant compound IPPD / TMQ with FTIR spectrophotometer shows some typical infrared absorption peak at the wave number (1 / λ) 833-895 cm-1 for cluster / CH bonds, 1,313 cm-1 for group / single bond Si-O, 1368 cm-1 to g ugus / single bond CC, 1507 cm-1, for cluster / bond C = C, 1665 cm-1For cluster / bond-C = O, 2128 cm-1 is the group / bond CN single, 3371

  19. Reflectance spectroscopy of oxalate minerals and relevance to Solar System carbon inventories

    Science.gov (United States)

    Applin, Daniel M.; Izawa, Matthew R. M.; Cloutis, Edward A.

    2016-11-01

    The diversity of oxalate formation mechanisms suggests that significant concentrations of oxalic acid and oxalate minerals could be widely distributed in the Solar System. We have carried out a systematic study of the reflectance spectra of oxalate minerals and oxalic acid, covering the 0.2-16 μm wavelength region. Our analyses show that oxalates exhibit unique spectral features that enable discrimination between oxalate phases and from other commonly occurring compounds, including carbonates, in all regions of the spectrum except for the visible. Using these spectral data, we consider the possible contribution of oxalate minerals to previously observed reflectance spectra of many objects throughout the Solar System, including satellites, comets, and asteroids. We find that polycarboxylic acid dimers and their salts may explain the reflectance spectra of many carbonaceous asteroids in the 3 μm spectral region. We suggest surface concentration of these compounds may be a type of space weathering from the photochemical and oxidative decomposition of the organic macromolecular material found in carbonaceous chondrites. The stability and ubiquity of these minerals on Earth, in extraterrestrial materials, and in association with biological processes make them useful for many applications in Earth and planetary sciences.

  20. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit.

    Science.gov (United States)

    Nguyễn, Hà Vũ Hồng; Savage, Geoffrey P

    2013-03-05

    Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L.) and golden (Actinidia chinensis L.) were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW) and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW) when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW), while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  1. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit

    Directory of Open Access Journals (Sweden)

    Hà Vũ Hồng Nguyễn

    2013-03-01

    Full Text Available Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L. and golden (Actinidia chinensis L. were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW, while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  2. Insights into the mechanism of copper-tolerance in Fibroporia radiculosa: The biosynthesis of oxalate

    Science.gov (United States)

    Katie Jenkins; Carol A. Clausen; Frederick Green; Susan V. Diehl

    2015-01-01

    Copper is currently used as the key component in wood preservatives despite the known tolerance of many brown-rot Basidiomycetes. Copper-tolerant fungi, like Fibroporia radiculosa, produce and accumulate high levels of oxalate when exposed to copper. To gain insight into the mechanism of oxalate production, four F. radiculosa...

  3. Evaluating the Mechanism of Oxalate Synthesis of Fibroporia Radiculosa Isolates Adapting to Copper-Tolerance

    Science.gov (United States)

    Katie Marie Jenkins

    2012-01-01

    Despite the drawbacks associated with tolerant organisms, copper is still used as the key component in current wood preservatives. Copper-tolerant fungi, like Fibroporia radiculosa, produce and accumulate high levels of oxalate in response to copper. The biosynthesis of oxalate has been connected to specific enzymes in the glyoxylate and...

  4. The effects of copper proximity on oxalate production in Fibroporia radiculosa

    Science.gov (United States)

    Katie M. Jenkins; Carol A. Clausen; Frederick Green III

    2014-01-01

    Copper remains a key component used in wood preservatives available today. However, the observed tolerance of several critical wood rotting organisms continues to be problematic. Tolerance to copper has been linked to the production and accumulation of oxalate, which precipitates copper into insoluble copper-oxalate crystals, thus inactivating copper ions. The purpose...

  5. Kinetic Spectrophotometric Method for Determination of Oxalic Acid and Its application in Lathyrus sativus

    Institute of Scientific and Technical Information of China (English)

    YAN Ze-Yi; XING Geng-Mei; LI Zhi-Xiao

    2003-01-01

    @@ Oxalic acid is one of the most common nutrient chelators in the human diet found in many vegetables, such as mushroom, spinach, fresh kidney beans, rhubarb leaves and beet leaves. Some recent reports demonstrate that oxalate plays an important role in resistance stress metabolism and steady state regulation in plant. [1

  6. Renal histopathology and crystal deposits in patients with small bowel resection and calcium oxalate stone disease.

    Science.gov (United States)

    Evan, Andrew P; Lingeman, James E; Worcester, Elaine M; Bledsoe, Sharon B; Sommer, Andre J; Williams, James C; Krambeck, Amy E; Philips, Carrie L; Coe, Fredric L

    2010-08-01

    We present here the anatomy and histopathology of kidneys from 11 patients with renal stones following small bowel resection, including 10 with Crohn's disease and 1 resection in infancy for unknown cause. They presented predominantly with calcium oxalate stones. Risks of formation included hyperoxaluria (urine oxalate excretion greater than 45 mg per day) in half of the cases, and acidic urine of reduced volume. As was found with ileostomy and obesity bypass, inner medullary collecting ducts (IMCDs) contained crystal deposits associated with cell injury, interstitial inflammation, and papillary deformity. Cortical changes included modest glomerular sclerosis, tubular atrophy, and interstitial fibrosis. Randall's plaque (interstitial papillary apatite) was abundant, with calcium oxalate stone overgrowth similar to that seen in ileostomy, idiopathic calcium oxalate stone formers, and primary hyperparathyroidism. Abundant plaque was compatible with the low urine volume and pH. The IMCD deposits all contained apatite, with calcium oxalate present in three cases, similar to findings in patients with obesity bypass but not an ileostomy. The mechanisms for calcium oxalate stone formation in IMCDs include elevated urine and presumably tubule fluid calcium oxalate supersaturation, but a low calcium to oxalate ratio. However, the mechanisms for the presence of IMCD apatite remain unknown.

  7. Oxalic acid biosynthesis is encoded by an operon in Burkholderia glumae

    Science.gov (United States)

    Although the biosynthesis of oxalic acid is known to occur in a number of bacteria, the mechanism(s) regulating its production remains largely unknown. To date, there is no report on the identification of an oxalic acid biosynthetic pathway gene from bacteria. In an attempt to identify such a gene...

  8. An oxalyl-CoA synthetase is important for oxalate metabolism in Saccharomyces cerevisiae

    Science.gov (United States)

    Although oxalic acid is common in nature, our understanding of the mechanism(s) regulating its turnover remains incomplete. In this study we identify Saccharomyces cerevisiae acyl-activating enzyme 3 (ScAAE3) as an enzyme capable of catalyzing the conversion of oxalate to oxalyl-CoA. Based on our fi...

  9. Hydrogen bonding in oxalic acid and its complexes: A database study of neutron structures

    Indian Academy of Sciences (India)

    R Chitra; Amit Das; R R Choudhury; M Ramanadham; R Chidambaram

    2004-08-01

    The basic result of carboxylic group that the oxygen atom of the –OH never seems to be a hydrogen bond acceptor is violated in the cases, namely urea oxalic acid and bis urea oxalic acid complexes, where the hydroxyl oxygen atom is an acceptor of a weak N–H... O hydrogen bond. The parameters of this hydrogen bond, respectively in these structures are: hydrogen acceptor distance 2.110 Å and 2.127 Å and the bending angle at hydrogen, 165.6° and 165.8°. The bond strength around the hydroxyl oxygen is close to 1.91 valence units, indicating that it has hardly any strength left to form hydrogen bonds. These two structures being highly planar, force the formation of this hydrogen bond. As oxalic acid is the common moiety, the structures of the two polymorphs, -oxalic acid and -oxalic acid, also were looked into in terms of hydrogen bonding and packing.

  10. Facile fabrication of cobalt oxalate nanostructures with superior specific capacitance and super-long cycling stability

    Science.gov (United States)

    Cheng, Guanhua; Si, Conghui; Zhang, Jie; Wang, Ying; Yang, Wanfeng; Dong, Chaoqun; Zhang, Zhonghua

    2016-04-01

    Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g-1 at the current density of 6 A g-1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g-1 to 30 A g-1. More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density.

  11. Calcium oxalate crystals in eucalypt ectomycorrhizae: morphochemical characterization.

    Directory of Open Access Journals (Sweden)

    Victor Satler Pylro

    Full Text Available Ectomycorrhizal fungi are ubiquitous in forest ecosystems, benefitting plants principally by increasing the uptake of water and nutrients such as calcium from the soil. Previous work has demonstrated accumulation of crystallites in eucalypt ectomycorrhizas, but detailed morphological and chemical characterization of these crystals has not been performed. In this work, cross sections of acetic acid-treated and cleared ectomycorrhizal fragments were visualized by polarized light microscopy to evaluate the location of crystals within cortical root cells. Ectomycorrhizal sections were also observed by scanning electron microscopy (SEM coupled with energy dispersive x-ray (EDS microprobe analysis. The predominant forms of crystals were crystal sand (granules and concretions. Calcium, carbon and oxygen were detected by EDS as constituent elements and similar elemental profiles were observed between both crystal morphologies. All analyzed crystalline structures were characterized as calcium oxalate crystals. This is the first report of the stoichiometry and morphology of crystals occurring in eucalypt ectomycorrhizas in tropical soils. The data corroborates the role of ectomycorrhizae in the uptake and accumulation of calcium in the form of calcium oxalate crystals in hybrid eucalypt plants.

  12. Hydroxyl radical substitution in halogenated carbonyls: oxalic acid formation.

    Science.gov (United States)

    Christiansen, Carrie J; Dalal, Shakeel S; Francisco, Joseph S; Mebel, Alexander M; Gaffney, Jeffrey S

    2010-03-04

    An ab initio study of OH radical substitution reactions in halogenated carbonyls is conducted. Hydroxyl radical substitution into oxalyl dichloride [ClC(O)C(O)Cl] and oxalyl dibromide [BrC(O)C(O)Br], resulting in the formation of oxalic acid, is presented. Analogous substitution reactions in formyl chloride [ClCH(O)], acetyl chloride [ClC(O)CH(3)], formyl bromide [BrCH(O)], and acetyl bromide [BrC(O)CH(3)] are considered. Energetics of competing hydrogen abstraction reactions for all applicable species are computed for comparison. Geometry optimizations and frequency computations are performed using the second-order Møller-Plesset perturbation theory (MP2) and the 6-31G(d) basis set for all minimum species and transition states. Single point energy computations are performed using fourth-order Møller-Plesset perturbation theory (MP4) and coupled cluster theory [CCSD(T)]. Potential energy surfaces, including activation energies and enthalpies, are determined from the computations. These potential energy surfaces show that OH substitution into ClC(O)C(O)Cl and BrC(O)C(O)Br, resulting in the formation of oxalic acid and other minor products, is energetically favorable. Energetics of analogous reactions with ClCH(O), BrCH(O), ClC(O)CH(3), and BrC(O)CH(3) are also computed.

  13. Raman spectroscopy study of calcium oxalate extracted from cacti stems.

    Science.gov (United States)

    Frausto-Reyes, Claudio; Loza-Cornejo, Sofia; Terrazas, Teresa; Terrazas, Tania; Miranda-Beltrán, María de la Luz; Aparicio-Fernández, Xóchitl; López-Macías, Brenda M; Morales-Martínez, Sandra E; Ortiz-Morales, Martín

    2014-01-01

    To find markers that distinguish the different Cactaceae species, by using near infrared Raman spectroscopy and scanning electron microscopy, we studied the occurrence, in the stem, of solid deposits in five Cactaceae species (Coryphantha clavata, Ferocactus latispinus, Opuntia ficus-indica, O. robusta, and O. strepthacantha) collected from their natural habitats from a region of México. The deposits in the tissues usually occurred as spheroidal aggregates, druses, or prismatic crystals. From the Raman spectra, the crystals were identified either as calcium oxalate monohydrate (CaC2O4·H2O) or calcium oxalate dihydrate (CaC2O4·2H2O). Opuntia species (subfamily Opuntioideae) showed the presence of CaC2O4·H2O, and the deposition of CaC2O4·2H2O was present in C. clavata and F. latispinus (subfamily Cactoideae, Cacteae tribe). As a punctual technique, Raman spectroscopy seems to be a useful tool to identify crystal composition. In addition to allowing the analysis of crystal morphology, this spectroscopic technique can be used to identify Cactaceae species and their chemotaxonomy.

  14. Cellular adaptive response of distal renal tubular cells to high-oxalate environment highlights surface alpha-enolase as the enhancer of calcium oxalate monohydrate crystal adhesion.

    Science.gov (United States)

    Kanlaya, Rattiyaporn; Fong-Ngern, Kedsarin; Thongboonkerd, Visith

    2013-03-27

    Hyperoxaluria is one of etiologic factors of calcium oxalate kidney stone disease. However, response of renal tubular cells to high-oxalate environment remained largely unknown. We applied a gel-based proteomics approach to characterize changes in cellular proteome of MDCK cells induced by 10mM sodium oxalate. A total of 14 proteins were detected as differentially expressed proteins. The oxalate-induced up-regulation of alpha-enolase in whole cell lysate was confirmed by 2-D Western blot analysis. Interaction network analysis revealed that cellular adaptive response under high-oxalate condition involved stress response, energy production, metabolism and transcriptional regulation. Down-regulation of RhoA, which was predicted to be associated with the identified proteins, was confirmed by immunoblotting. In addition, the up-regulation of alpha-enolase on apical surface of renal tubular epithelial cells was also confirmed by immunoblotting of the isolated apical membranes and immunofluorescence study. Interestingly, blockage of alpha-enolase expressed on the cell surface by antibody neutralization significantly reduced the number of calcium oxalate monohydrate (COM) crystals adhered on the cells. These results strongly suggest that surface alpha-enolase plays an important role as the enhancer of COM crystal binding. The increase of alpha-enolase expressed on the cell surface may aggravate kidney stone formation in patients with hyperoxaluria. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. 手性氨基亚磺酰胺的合成及其对N-苯基酮亚胺不对称还原的催化作用%Synthesis of Chiral Amino Sulfinamides and Their Catalyzed Asymmetric Reduction of N-phenyl Ketimine

    Institute of Scientific and Technical Information of China (English)

    王萌; 王超; 卢晓霞; 孙健

    2011-01-01

    A series of novel organocatalysts, chiral amino sulfinamides (5a ~ 5f), were synthesized from N-protected chiral amino alcohol via oxidation, reacting with chiral t-butyl sulfonamide and reductive amination. 5 was further applied in the asymmetric hydrosilylation of N-phenyl ketimine by HSiCl3 to give chiral N-phenyl-methylbenzyl amine in moderate yield and enantioselectivity.%从N-保护的手性氨基醇出发,经氧化成醛后,与手性叔丁基亚磺酰胺发生缩合反应,再经一步还原胺化合成了一系列新型手性氨基亚磺酰胺有机小分子催化剂.将其应用于N-苯基酮亚胺的不对称硅氢化反应中,以中等收率和对映选择性获得了相应的N-苯基手性胺.

  16. Enzymatic mechanism of oxalate production in the TCA and glyoxylate pathways using various isolates of Antrodia radiculosa

    Science.gov (United States)

    K.M. Jenkins; S.V. Diehl; C.A. Clausen; F. Green

    2011-01-01

    Brown-rot fungi produce oxalate in large amounts; however, levels of accumulation and function vary by species. Copper-tolerant fungi, like Antrodia radiculosa, produce and accumulate high levels of oxalate in response to copper. Oxalate biosynthesis in copper-tolerant fungi has been linked to the glyoxylate and tricarboxylic acid (TCA) cycles. Within these two cycles...

  17. A Comparative Study on Several Models of Experimental Renal Calcium Oxalate Stones Formation in Rats

    Institute of Scientific and Technical Information of China (English)

    LIU Jihong; CAO Zhenggno; ZHANG Zhaohui; ZHOU Siwei; YE Zhangqun

    2007-01-01

    In order to compare the effects of several experimental renal calcium oxalate stones formation models in rats and to find a simple and convenient model with significant effect of calcium oxalate crystals deposition in the kidney, several rat models of renal calcium oxalate stones formation were induced by some crystal-inducing drugs (CID) including ethylene glycol (EG), ammonium chloride (AC), vitamin D3 [1α(OH)VitD3, alfacalcidol], calcium gluconate, ammonium oxalate, gentamicin sulfate, L-hydroxyproline. The rats were fed with drugs given singly or unitedly. At the end of experiment, 24-h urines were collected and the serum creatinine (Cr), blood urea nitrogen (BUN), the extents of calcium oxalate crystal deposition in the renal tissue, urinary calcium and oxalate excretion were measured. The serum Cr levels in the stone-forming groups were significantly higher than those in the control group except for the group EG+L-hydroxyproline, group calcium gluconate and group oxalate. Blood BUN concentration was significantly higher in rats fed with CID than that in control group except for group EG+L-hydroxyproline and group ammonium oxalate plus calcium gluconate. In the group of rats administered with EG plus Vitamin D3, the deposition of calcium oxalate crystal in the renal tissue and urinary calcium excretion were significantly greater than other model groups. The effect of the model induced by EG plus AC was similar to that in the group induced by EG plus Vitamin D3. EG plus Vitamin D3 or EG plus AC could stably and significantly induced the rat model of renal calcium oxalate stones formation.

  18. Protection of metal artefacts with the formation of metal-oxalates complexes by Beauveria bassiana.

    Directory of Open Access Journals (Sweden)

    Edith eJoseph

    2012-01-01

    Full Text Available Several fungi present high tolerance to toxic metals and some are able to transform metals into metal-oxalate complexes. In this study, the ability of Beauveria bassiana to produce copper oxalates was evaluated in vitro. Growth performance was tested on various copper-containing media. B. bassiana proved highly resistant to copper, tolerating concentrations of up to 20 g.L-1, and precipitating copper oxalates on all media tested. Chromatographic analyses showed that this species produced oxalic acid as sole metal chelator. The production of metal-oxalates can be used in the restoration and conservation of archaeological and modern metal artefacts. The production of copper-oxalates was confirmed directly using metallic pieces (both archaeological and modern. The conversion of corrosion products into copper oxalates was demonstrated as well. In order to assess whether the capability of B. bassiana to produce metal-oxalates could be applied to other metals, iron and silver were tested as well. Iron appears to be directly sequestered in the wall of the fungal hyphae forming oxalates and probably goethite. However, the formation of a homogeneous layer on the object is not yet optimal. Silver nitrate was extracellularly reduced into nanoparticles of elemental silver by an unknown mechanism. The production of copper oxalates is immediately applicable for the conservation of copper-based artefacts. For iron and silver this is not yet the case. However, the vast ability of B. bassiana to transform toxic metals using different immobilization mechanisms seems to offer considerable possibilities for industrial applications, such as the bioremediation of contaminated soils or the green synthesis of chemicals.

  19. Proteomic Analysis after Sequential Extraction of Matrix Proteins in Urinary Stones Composed of Calcium Oxalate Monohydrate and Calcium Oxalate Dihydrate.

    Science.gov (United States)

    Kaneko, Kiyoko; Nishii, Shin-ichiro; Izumi, Yoko; Yasuda, Makoto; Yamanobe, Tomoyo; Fukuuchi, Tomoko; Yamaoka, Noriko; Horie, Shigeo

    2015-01-01

    In this study, we performed proteomic analysis following sequential protein extraction on calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) urinary stones to determine the specific matrix proteins according to the crystal components of the stones. After X-ray and IR analysis of 13 urinary stones, matrix proteins were sequentially extracted with KCl, formic acid, guanidine-HCl, and EDTA, before SDS-electrophoresis followed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The electrophoretic patterns of the extracted proteins differed from that of COM and COD stones. LC-MS/MS identified 65 proteins, of which many were cellular plasma proteins, and were frequently detected regardless of the crystal components. However, 6 proteins (protein Z, protein S, prothrombin, osteopontin, fatty acid binding protein 5, and ubiquitin) were detected in the final EDTA fractions of COM stones. These proteins are involved in the coagulation process or osteometabolism, and thus the roles they play are of particular interest.

  20. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    Directory of Open Access Journals (Sweden)

    G. Cailleau

    2011-07-01

    Full Text Available An African oxalogenic tree, the iroko tree (Milicia excelsa, has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi. Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate

  1. [The evaluation of anti-nutritive components in beer on the example of oxalic acid].

    Science.gov (United States)

    Salamon, Agnieszka; Baca, Elzbieta; Baranowski, Krzysztof; Michałowska, Dorota

    2012-01-01

    Food in its composition contains anti-nutritional substances that reduces or prevents the use of valuable nutrients. The oxalic acid, as phytate and dietary fiber, occurs naturally in foods of plant origin, to which the beer is classified. The negative effect of oxalic acid is reducing the bioavailability of calcium and magnesium, and disorder of metabolism of the body's absorption of these elements from the diet. The excess of oxalic acid and its salt in the diet contributes to the formation of certain diseases, such as oxalate urolithiasis, osteoporosis, arthritis, etc. Due to the diuretic effect of beer, drinking moderate amounts of it is recommended as a preventive and support urinary tract disorders. The aim of this study was to determine and comparison the oxalic acid content in selected beers available on the Polish market. Fifty seven samples of beer were used for this study. These samples were divided into three groups depending on the alcohol concentration declared by the producers (1st group--below 5.5% vol., 2nd group--from 5.5 to 6.5% vol., 3rd group--above 6.5% vol.). The beer samples were incubated in the ultrasonic bath for 15 minutes following pH adjustments up to pH = 2 with the 1 mol/L hydrochloric acid to transform calcium oxalates into soluble form, then filtered. The oxalic acid concentration was measured by high performance liquid chromatography (HPLC) with conductivity detection. The concentration of oxalic acid in tested samples of beer ranged from 1.8 to 30.3 mg/L. No considerable differences between the concentration of oxalic acid in the three tested group of beer with the various content of the alcohol were found. Basing on the average concentrations of the oxalic acid in the different groups of the tested beers the positive trend in oxalic acid concentration related to the increase of alcohol could be observed. The very low concentration of oxalic acid allows to classify beer as food product safe for the human health in terms of low

  2. [Catalytic ozonation by ceramic honeycomb for the degradation of oxalic acid in aqueous solution].

    Science.gov (United States)

    Zhao, Lei; Sun, Zhi-Zhong; Ma, Jun

    2007-11-01

    Comparative experiments for the degradation of oxalic acid in aqueous solution were carried out in the three processes of ozonation alone, ceramic honeycomb-catalyzed ozonation and ceramic honeycomb adsorption. The results show that the degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation, ozonation alone and ceramic honeycomb adsorption systems are 37.6%, 2.2% and 0.4%, and the presence of ceramic honeycomb catalyst significantly improves the degradation rate of oxalic acid compared to the results from non-catalytic ozonation and adsorption. With the addition of tert-butanol, the degradation rates of oxalic acid in catalytic ozonation system decrease by 24.1%, 29.0% and 30.1%, respectively, at the concentration of 5, 10 and 15 mg x L(-1). This phenomenon indicates that ceramic honeycomb-catalyzed ozonation for the degradation of oxalic acid in aqueous solution follows the mechanism of *OH oxidation, namely the heterogeneous surface of catalyst enhances the initiation of *OH. The results of TOC analysis demonstrate that the process of ceramic honeycomb-catalyzed ozonation can achieve the complete mineralization level without the formation of intermediary degradation products. The experimental results suggest that the reaction temperature has positive relationship with the degradation rate of oxalic acid. The degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation system are 16.4%, 37.6%, 61.3% and 68.2%, at the respective reaction temperature of 10, 20, 30 and 40 degrees C.

  3. Synergistic effects of the combination of oxalate and ascorbate on arsenic extraction from contaminated soils.

    Science.gov (United States)

    Lee, Jae-Cheol; Kim, Eun Jung; Baek, Kitae

    2017-02-01

    Arsenic is often associated with iron oxides in soils due to its high affinity with iron oxides and the abundance of iron oxides in the environment. Dissolution of iron oxides can subsequently release arsenic associated with them into the environment, which results in the increase of arsenic mobility in the soil environment. In this study, arsenic extraction from soils via the dissolution of iron oxides was investigated using oxalate, ascorbate, and their combination in order to effectively remediate arsenic-contaminated soils. Oxalate mainly extracted iron from soils via a ligand-promoted reaction, while ascorbate extracted iron mainly via a reductive reaction. Arsenic extractions from soils by oxalate and ascorbate were shown to behave similarly to iron extractions, indicating the concurrent release of arsenic adsorbed on iron oxides upon the dissolution of iron oxides. The combination of oxalate and ascorbate greatly increased arsenic extraction, indicating the synergistic effects of the combination of oxalate and ascorbate on iron and arsenic extraction from soils. Oxalate and ascorbate are naturally-occurring organic reagents that have chelating and reducing capacity. Therefore, the use of oxalate and ascorbate is environmentally friendly and effective for the remediation of arsenic-contaminated soils.

  4. Urinary oxalate excretion by very low birth weight infants receiving parenteral nutrition.

    Science.gov (United States)

    Campfield, T; Braden, G

    1989-11-01

    Renal calcifications have been described in very low birth weight (VLBW) infants, and diuretic drug-associated hypercalciuria is believed to play a role in the pathogenesis of this lesion. Hyperoxaluria is an important cause of renal stone formation in children and adults. Because parenteral nutrition solutions contain the oxalate precursors ascorbate and glycine, the relationship between total parenteral nutrition administration and oxalate excretion in VLBW infants was examined. Administration of approximately 0.5 g of total parenteral nutrition protein per kilogram per day to VLBW infants was associated with an increased urinary oxalate concentration and an increased urinary oxalate to creatinine ratio, when compared with VLBW infants receiving a glucose and electrolyte solution. A further increase in urinary oxalate concentration and oxalate to creatinine ratio was noted when total parenteral nutrition protein was increased to approximately 1.5 g of protein per kilogram per day. In VLBW infants who receive total parenteral nutrition, elevated urinary oxalate concentrations may develop and may be a factor in the pathogenesis of nephrocalcinosis in these infants.

  5. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    Science.gov (United States)

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign.

  6. The control of Varroa destructor using oxalic acid.

    Science.gov (United States)

    Gregorc, Ales; Planinc, I

    2002-05-01

    Twenty-four honeybee (Apis mellifera) colonies were used to monitor the efficacy of a solution of 2.9% oxalic acid (OA) and 31.9% sugar against the mite Varroa destructor. Mite mortality was established prior to and after OA treatments, which were conducted in August and September. The treatments resulted in 37% mite mortality as opposed to 1.11% in the controls. OA treatment conducted in September on previously untreated colonies resulted in 25% mite mortality. OA treatments in October and November resulted in approximately 97% mite mortality. These results suggest that OA is effective during the broodless period and less effective when applied to colonies with capped broods. The possible use of OA against the Varroa mite in honeybee colonies as an alternative to routine chemical treatments is discussed.

  7. The structural dynamics in the proton-conducting imidazolium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Rachocki, Adam; Pogorzelec-Glaser, Katarzyna; Tritt-Goc, Jadwiga [Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznan (Poland); Pietraszko, Adam [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland)], E-mail: radam@ifmpan.poznan.pl

    2008-12-17

    The {sup 1}H spin-lattice relaxation times and high-resolution solid-state nuclear magnetic resonance (NMR) under fast magic spinning were used to study the structural dynamics in the proton-conducting material imidazolium oxalate. The measurements provide evidence for the ordered and disordered domains within the studied material. The two components drastically differ in their {sup 1}H spin-lattice relaxation times and {sup 1}H-{sup 13}C cross-polarization magic-angle-spinning (CP/MAS) spectra. The coalescence phenomenon of the resonances of the basal carbons of the imidazole ring undergoing a reorientation is observed only for mobile molecules in the disordered domains. Therefore, only these molecules can be responsible for proton conductivity allowing for the Grotthus mechanism.

  8. Biocompatible laponite ionogels based non-enzymatic oxalic acid sensor

    Directory of Open Access Journals (Sweden)

    Nidhi Joshi

    2015-09-01

    Full Text Available An enzyme-free oxalic acid (OA electrochemical sensor was assembled on indium tin oxide (ITO plate on which a film of laponite ionogel was coated that resulted in an L/IL/ITO electrode. This ionogel electrode was characterized by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and UV–Vis spectroscopy techniques. Electrochemical oxidation of OA on the electrode surface was investigated by cyclic voltammetry. Further this electrode exhibited high electrochemical activity that yielded well-defined peaks of OA oxidation, and a notably suppressed over-potential compared to the laponite–ITO (L/ITO electrode. Under optimized conditions, a good linear response (anodic current was observed for the OA concentration in the 1–20 mM range with a detection limit of 3 μM. Furthermore, this electrochemical strip sensor presented good characteristics in terms of stability, and reproducibility offering promise of applicability of this green sensor platform.

  9. Optimization of air-sparged plutonium oxalate/hydroxide precipitators

    Energy Technology Data Exchange (ETDEWEB)

    VanderHeyden, W.B.; Yarbro, S.L.; Fife, K.W.

    1997-04-01

    The high cost of waste management and experimental work makes numerical modeling an inexpensive and attractive tool for optimizing and understanding complex chemical processes. Multiphase {open_quotes}bubble{close_quotes} columns are used extensively at the Los Alamos Plutonium Facility for a variety of different applications. No moving parts and efficient mixing characteristics allow them to be used in glovebox operations. Initially, a bubble column for oxalate precipitations is being modeled to identify the effect of various design parameters such as, draft tube location, air sparge rate and vessel geometry. Two-dimensional planar and axisymmetric models have been completed and successfully compared to literature data. Also, a preliminary three-dimensional model has been completed. These results are discussed in this report along with future work.

  10. Charge dynamics in conducting polyaniline–metal oxalate composites

    Indian Academy of Sciences (India)

    R Murugesan; E Subramanian

    2003-08-01

    Polyaniline (Pani) and its metal oxalate composites (∼ 10 wt.%) of trivalent metal ions of Cr, Fe, Mn, Co and Al were synthesized by chemical oxidative polymerization technique with potassium perdisulphate oxidant in aqueous sulphuric acid medium. These materials were characterized by UV–VIS and EPR spectral techniques. Their d.c. electrical conductivities at room temperature and also as a function of temperature (307–453 K) were measured by four-probe technique. Presence of radical cation/polaron transition was indicated by UV–VIS absorption peak and EPR signals. Further, a close correlation existed between the conductivities and EPR parameters such as line width and peak ratio, which demonstrated that both mobile and fixed spins are involved in these composites. The dependence of conductivity on temperature, when analysed graphically by VRH, GB and TC mechanisms, pointed out that VRH is the predominant charge transport mechanism in these materials.

  11. Thorium adsorption behaviour on mixed ammonium lanthanum oxalate, LAOX

    Energy Technology Data Exchange (ETDEWEB)

    Valentini Ganzerli, M.T.; Maggi, L.; Crespi Caramella, V

    1999-07-01

    The cation-exchange properties of mixed ammonium lanthanum oxalate, LAOX, were studied by batch equilibration as a function of the concentration of some cations, such as alkaline earths or ammonium and of some anions and acids. The distribution coefficients for thorium are high, while U(VI) is not adsorbed over a large acidity range. Thus, the separation of thorium from uranium may be successfully carried out. The experimental conditions of adsorption, elution and recovery of thorium were investigated as well, by using chromatographic columns filled with LAOX, in order to set best the separation conditions from uranyl ions. Instrumental neutron activation analysis, ICP emission spectrometry and the UV spectrometry were used to evaluate the thorium, uranium and lanthanum concentrations00.

  12. Calcium oxalate monohydrate precipitation investigation by thermometric method

    Science.gov (United States)

    Söhnel, O.; Costa-Bauzá, A.; Velich, V.

    1993-01-01

    Calcium oxalate monohydrate (COM) precipitation from diluted solutions of 100 mol m -3 ionic strength at 25°C was studied by an isoperibolic reaction twin calorimeter. The molar reaction enthalpy was determined as - 17.5 kJ mol -1. Results achieved with a pure system were highly reproducible. Citrate, pyrophosphate and phytate retard COM precipitation that is manifested mainly by an induction period appearance and a decrease of the initial precipitation rate. Effect of the studied impurities on individual precipitation experiments carried out under identical conditions was to some extent "random", i.e. the reaction extent reached at arbitrary time considerably differed for individual experiments. Impurity effectiveness in retarding spontaneous precipitation increases in succession citrate phytate.

  13. Growth and characterisation of gadolinium samarium oxalate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Korah, I. [Dept. of Physics, St. George College, Aruvithura - 686122, Kerala (India); Joseph, C. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam - 686562 (India); Ittyachan, M.A. [Dept. of Physics, Cochin University of Science and Technology, Cochin (India)

    2007-10-15

    Single crystals of Gadolinium Samarium Oxalate (GSO) are grown by gel method. The crystals are pale yellowish in colour. Morphology and size of the crystals are found to depend on pH of the medium, gel density, concentration of the reactants and acidity of the feed solution. The crystallinity of the grown sample was confirmed by X-ray diffraction studies and the lattice parameters were determined. X-ray diffractogram shows well defined peaks. IR spectrum confirms the presence of water molecules and carboxylic group. EDAX analysis confirms the presence of Gd and Sm in the sample. The thermal decomposition behaviour of the crystal was analysed using TGA and DTA studies. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Oxalic acid production by citric acid-producing Aspergillus niger overexpressing the oxaloacetate hydrolase gene oahA.

    Science.gov (United States)

    Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro

    2014-05-01

    The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC 3.7.1.1), were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host.

  15. EFFECTIVENESS OF USING DILUTE OXALIC ACID TO DISSOLVEHIGH LEVEL WASTE IRON BASED SLUDGE SIMULANT

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E

    2008-07-11

    At the Savannah River Site (SRS), near Aiken South Carolina, there is a crucial need to remove residual quantities of highly radioactive iron-based sludge from large select underground storage tanks (e.g., 19,000 liters of sludge per tank), in order to support tank closure. The use of oxalic acid is planned to dissolve the residual sludge, hence, helping in the removal. Based on rigorous testing, primarily using 4 and 8 wt% oxalic acid solutions, it was concluded that the more concentrated the acid, the greater the amount of residual sludge that would be dissolved; hence, a baseline technology on using 8 wt% oxalic acid was developed. In stark contrast to the baseline technology, reports from other industries suggest that the dissolution will most effectively occur at 1 wt% oxalic acid (i.e., maintaining the pH near 2). The driver for using less oxalic acid is that less (i.e., moles) would decrease the severity of the downstream impacts (i.e., required oxalate solids removal efforts). To determine the initial feasibility of using 1 wt% acid to dissolve > 90% of the sludge solids, about 19,000 liters of representative sludge was modeled using about 530,000 liters of 0 to 8 wt% oxalic acid solutions. With the chemical thermodynamic equilibrium based software results showing that 1 wt% oxalic acid could theoretically work, simulant dissolution testing was initiated. For the dissolution testing, existing simulant was obtained, and an approximate 20 liter test rig was built. Multiple batch dissolutions of both wet and air-dried simulant were performed. Overall, the testing showed that dilute oxalic acid dissolved a greater fraction of the stimulant and resulted in a significantly larger acid effectiveness (i.e., grams of sludge dissolved/mole of acid) than the baseline technology. With the potential effectiveness confirmed via simulant testing, additional testing, including radioactive sludge testing, is planned.

  16. REINVESTIGATING THE PROCESS IMPACTS FROM OXALIC ACIDHIGH LEVEL WASTE TANK CLEANING

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E

    2008-01-22

    The impacts and acceptability of using oxalic acid to clean the Savannah River Site, High Level Waste Tanks 1-8, were re-investigated using a two-phased approach. For the first phase, using a representative Tank 1-8 sludge, the chemical equilibrium based software, OLI ESP{copyright} and Savannah River Site laboratory test results were used to develop a chemically speciated material balance and a general oxalate mass balance. Using 8 wt% oxalic acid with a 100% molar excess, for every 1 kg of sludge solid that was dissolved, about 3.4 kg of resultant solids would form for eventual vitrification, while about 0.6 kg of soluble oxalate would precipitate in the evaporator system, and form a salt heel. Using available analyses, a list of potential safety and process impacts were developed, screened, and evaluated for acceptability. The results showed that the use of oxalic acid had two distinct types of impacts, those which were safety based and required potential upgrades or additional studies. Assuming such were performed and adequate, no further actions were required. The second type of impacts were also acceptable, but were long-term, and as such, would need to be managed. These impacts were directly caused by the solubility characteristics of oxalate in a concentrated sodium solution and, occurred after pH restoration. Since oxalate destruction methods are commonly available, their use should be considered. Using an oxalate destruction method could enable the benefits of oxalic to applied, while eliminating the long-term impacts that must be managed, and hence should be considered.

  17. [Urinary calcium oxalate supersaturation beyond nephrolithiasis. Relationship with tubulointerstitial damage].

    Science.gov (United States)

    Toblli, Jorge E; Angerosa, Margarita; Stella, Inés; Ferder, León; Inserra, Felipe

    2003-01-01

    A number of studies have demonstrated that the urinary ion activity product (IAP) of calcium oxalate (CaOx), as an index of urinary CaOx supersaturation (SS), is higher in renal stone formers than in normal subjects. Besides, the relation between CaOx SS and lithogenesis, crystal CaOx exposition can produce tubular cell as well as renal interstitial lesions. The aim of our study was to evaluate the possible relationship between CaOx SS and tubulointerstitial (TI) damage in an animal model of hyperoxaluria. During four weeks, male Sprague-Dawley rats received: G1 (n = 8) control regular water, and G2 (n = 8) 1% ethylene glycol (ETG) (precursor for oxalates) in drinking water. In order to evaluate urinary CaOx SS, IAP assessed by Tisselius formula was performed. At the end of the study, renal lesions were evaluated by light microscopy and immunohistochemistry. Animals from G2 (ETG) presented higher (p intersticial fibrosis; e) interstitial alpha-smooth muscle actin; f) collagen type III; g) TI TGF beta 1 compared with G1 (control). Rats from G2 (ETG) presented a high correlation between urinary CaOx SS and most of the TI damage parameters evaluated, in especial with interstitial fibrosis. Both, inflammatory infiltrates and urinary CaOx SS were the most significant variables related to interstitial fibrosis. Finally, since hyperoxaluric animals showed higher urinary CaOx SS associated with higher renal TI damage, the results from this study suggest the presence of a tight link between urinary CaOx SS and renal TI damage. Considering these findings we think that urinary CaOx SS control rises in importance beyond nephrolithiasis.

  18. Manganese oxalate nanorods as ballistic modifier for composite solid propellants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Supriya [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India); Chawla, Mohit [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Siril, Prem Felix, E-mail: prem@iitmandi.ac.in [School of Basic Sciences, Indian Institute of Technology Mandi, Mandi 175005, H.P. (India); Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273009, U.P. (India)

    2014-12-10

    Highlights: • Manganese oxalate nanorods were prepared using mild thermal precipitation and aging. • The nanorods were found to be efficient ballistic modifier for solid propellants. • The nanorods sensitized the thermolysis of ammonium perchlorate. • Controlled thermal decomposition of nanorods yielded manganese oxide nanoparticles. • MnO nanoparticles formed insitu in the condensed phase enhance the burning rates. - Abstract: Rod-shaped nanostructures of manganese oxalate (MnC{sub 2}O{sub 4}) were synthesized via mild thermal precipitation and aging process. Chemical composition of the MnC{sub 2}O{sub 4} nanorods was confirmed using Fourier transform infra-red (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) and selected area electron diffraction (SAED) studies revealed the crystal structure. Field emission scanning electron microscopy (FE-SEM) imaging and high resolution transmission electron microscopy (HR-TEM) were employed to study the structural features of the nanorods. The MnC{sub 2}O{sub 4} nanorods were found to be efficient ballistic modifier for the burning rate enhancement of composite solid propellants (CSPs). Thermal analysis using TGA-DSC showed that MnC{sub 2}O{sub 4} nanorods sensitized the thermal decomposition of ammonium perchlorate (AP) and the CSPs. Controlled thermal decomposition of the MnC{sub 2}O{sub 4} nanorods resulted in the formation of managanese oxide nanoparticles with mesoporosity. A plausible mechanism for the burning rate enhancement using MnC{sub 2}O{sub 4} nanorods was proposed.

  19. Acute kidney injury after ingestion of rhubarb: secondary oxalate nephropathy in a patient with type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Albersmeyer Marc

    2012-10-01

    Full Text Available Abstract Background Oxalosis is a metabolic disorder characterized by deposition of oxalate crystals in various organs including the kidney. Whereas primary forms result from genetic defects in oxalate metabolism, secondary forms of oxalosis can result from excessive intestinal oxalate absorption or increased endogenous production, e.g. after intoxication with ethylene glycol. Case presentation Here, we describe a case of acute crystal-induced renal failure associated with excessive ingestion of rhubarb in a type 1 diabetic with previously normal excretory renal function. Renal biopsy revealed mild mesangial sclerosis, but prominent tubular deposition of oxalate crystals in the kidney. Oxalate serum levels were increased. Conclusion Acute secondary oxalate nephropathy due to excessive dietary intake of oxalate may lead to acute renal failure in patients with preexisting renal disease like mild diabetic nephropathy. Attention should be payed to special food behaviors when reasons for acute renal failure are explored.

  20. Growth kinetics of calcium oxalate monohydrate. III. Variation of solution composition

    Science.gov (United States)

    Bijvoet, Olav L. M.; Blomen, Leo J. M. J.; Will, Eric J.; van der Linden, Hanneke

    1983-11-01

    The influence of the variations of initial supersaturation, ionic strength and calcium-to-oxalate ratio on the growth kinetics of calcium oxalate monohydrate from suspension at 37°C have been investigated in an isotopic system. All experiments can be described with a single growth formula, containing three constants: kA (growth rate constant), La (thermodynamic solubility product) and [ tm] (a parameter describing the agglomeration of any seed suspension). This formula is able to predict any growth curve when the initial concentrations of seed, oxalate and indifferent electrolyte are known. Comparisons with datak from the literature are discussed.

  1. Blue luminescence in porous anodic alumina films: the role of the oxalic impurities

    CERN Document Server

    Gao Tao; Zhang Li

    2003-01-01

    Porous anodic alumina (PAA) films with ordered nanopore arrays have been prepared by electrochemically anodizing aluminium in oxalic acid solutions, and the role of the oxalic impurities in the optical properties of PAA films has been discussed. Photoluminescence (PL) measurements show that the PAA films obtained have a blue PL band with a peak position at around 470 nm; the oxalic impurities, incorporated in the PAA films during the anodization processes and already existing in them, could be being transformed into PL centres and hence responsible for this PL emission.

  2. Modulation of Tartrates with Various Counterions on the Phases of Calcium Oxalate in Gelatinous Systems

    Institute of Scientific and Technical Information of China (English)

    Jian Ming OUYANG; Xiang Ping LI

    2005-01-01

    Effect of various counterions of tartrate on the crystallization of calcium oxalate in gel system was investigated using scanning electron microscopy and X-ray diffraction. Various tartrates with hydrogen (H2tart), sodium (Na2tart), potassium (K2tart), ammonium ((NH4)2tart), and a mixture of sodium and potassium cations (NaKtart) were considered. For H2tart, Na2tart, and (NH4)2tart, calcium oxalate dihydrate (COD) was induced. However, for K2tart and NaKtart,calcium oxalate trihydrate (COT) was obtained.

  3. Kinetics of wet air oxidation of glyoxalic acid and oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shende, R.V.; Mahajani, V.V. (Univ. of Bombay (India). Dept. of Chemical Technology)

    1994-12-01

    Oxidation of lower molecular weight monobasic and dibasic acids such as formic acid, acetic acid, glyoxalic acid, and oxalic acid is often the rate-controlling step during wet air oxidation (WAO) of an aqueous waste stream exhibiting very high chemical oxygen demand (COD). The kinetics of WAO of glyoxalic acid and oxalic acid was studied in absence and presence of a cupric sulfate catalyst in the temperature range of 120--245 C and oxygen partial pressure of 0.345--1.380 MPa. The wet oxidation of oxalic acid was found to require more severe conditions as compared to glyoxalic acid. The reaction mechanism and kinetic model have been discussed.

  4. Is there a role for pentosan polysulfate in the prevention of calcium oxalate stones?

    Science.gov (United States)

    Jones, Marklyn; Monga, Manoj

    2003-12-01

    The clinical role for pentosan polysulfate (PPS) in the prevention of calcium oxalate urolithiasis is not known. Crystallization and aggregation are important steps in calcium oxalate stone formation, and PPS has been shown to inhibit these steps, both in vitro and in vivo. In addition, PPS has a role in repairing injured urothelium and inhibiting adhesion to epithelial defects. A randomized double-blind placebo-controlled study appears warranted to assess the utility of PPS in the prevention of recurrent calcium oxalate stones.

  5. Paramagnetic behaviour of silver nanoparticles generated by decomposition of silver oxalate

    Science.gov (United States)

    Le Trong, Hoa; Kiryukhina, Kateryna; Gougeon, Michel; Baco-Carles, Valérie; Courtade, Frédéric; Dareys, Sophie; Tailhades, Philippe

    2017-07-01

    Silver oxalate Ag2C2O4, was already proposed for soldering applications, due to the formation when it is decomposed by a heat treatment, of highly sinterable silver nanoparticles. When slowly decomposed at low temperature (125 °C), the oxalate leads however to silver nanoparticles isolated from each other. As soon as these nanoparticles are formed, the magnetic susceptibility at room temperature increases from -3.14 10-7 emu.Oe-1.g-1 (silver oxalate) up to -1.92 10-7 emu.Oe-1.g-1 (metallic silver). At the end of the oxalate decomposition, the conventional diamagnetic behaviour of bulk silver, is observed from room temperature to 80 K. A diamagnetic-paramagnetic transition is however revealed below 80 K leading at 2 K, to silver nanoparticles with a positive magnetic susceptibility. This original behaviour, compared to the one of bulk silver, can be ascribed to the nanometric size of the metallic particles.

  6. Crystal morphology and carbon/carbon composition of solid oxalate in cacti.

    Science.gov (United States)

    Rivera, E R; Smith, B N

    1979-12-01

    Morphology, crystal structure, and carbon isotopic composition of calcium oxalate from representative species from the family Cactaceae were determined using scanning electron microscopy, x-ray diffraction, and isotope ratio mass spectrometry. Crystals from one species in the Opuntieae tribe of the Cactaceae were druses with acute points composed of the monohydrate form of calcium oxalate (whewellite). Crystals from three species in the Cereeae tribe were the dihydrate form of calcium oxalate (weddellite) forming druses made up of tetragonal and isodiametric crystallites. The oxalate was relatively enriched in (13)C isotope (-7.3 to - 8.7 per thousand) compared with woody fibers (-13.3 to 14.1 per thousand) from the same plants.

  7. Crystal Morphology and 13Carbon/12Carbon Composition of Solid Oxalate in Cacti 1

    Science.gov (United States)

    Rivera, E. R.; Smith, B. N.

    1979-01-01

    Morphology, crystal structure, and carbon isotopic composition of calcium oxalate from representative species from the family Cactaceae were determined using scanning electron microscopy, x-ray diffraction, and isotope ratio mass spectrometry. Crystals from one species in the Opuntieae tribe of the Cactaceae were druses with acute points composed of the monohydrate form of calcium oxalate (whewellite). Crystals from three species in the Cereeae tribe were the dihydrate form of calcium oxalate (weddellite) forming druses made up of tetragonal and isodiametric crystallites. The oxalate was relatively enriched in 13C isotope (-7.3 to - 8.7 ‰) compared with woody fibers (-13.3 to 14.1 ‰) from the same plants. Images PMID:16661115

  8. Novel synthesis and characterization of nanocrystalline thoria from oxalate precursor via reverse micellar route

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R.; Aggarwal, S.K. [Bhabha Atomic Research Centre, Mumbai (India). Fuel Chemistry Div.; Gupta, S.K. [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.

    2013-03-01

    Nanoparticles of thorium oxalate were synthesized by the reaction of thorium nitrate and ammonium oxalate by the microemulsion method. The ThO{sub 2} nanoparticles were obtained by heating thorium oxalate nanoparticles at 500 C in air. The oxalate and oxide nanoparticles of thorium were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and selected area electron diffraction (SAED). X-ray diffraction studies showed the mono-phasic nature of the powder thoria. The particle size was obtained from X-ray line broadening ({proportional_to} 10 nm) and transmission electron microscopy ({proportional_to} 10 nm). Dynamic light scattering (DLS) was used to calculate the average grain size of the particles. SAED confirmed the nanocrystalline nature of thoria particles. High resolution transmission electron microscopy (HRTEM) was also carried out to understand the morphology of the system. The monodisperse nanoparticles of thoria are promising for future reactor technologies. (orig.)

  9. Oxalate complexation with aluminum(III) and iron(III) at moderately elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Tait, C.D.; Janecky, D.R.; Clark, D.L. [Los Alamos National Lab., NM (United States); Bennett, P.C. [Texas Univ., Austin, TX (United States). Dept. of Geological Sciences

    1992-05-01

    To add to our understanding of the weathering of rocks in organic rich environments such as sedimentary brines and oil field waters, we have examined the temperature dependent complexation of aluminum with oxalate. Raman vibrational studies show that even the association constant for the highly charged Al(ox){sub 3}{sup 3{minus}} unexpectedly increases with moderate temperature increases to 80{degrees}C. To evaluate the potential importance of these Al-oxalate species in complex natural systems, temperature dependent competition experiments Fe(III) and Al(III) for oxalate have been initiated. Similar to aluminum, ferric oxalates show increases in association constants at higher temperatures. In competition experiments, the first association constant for Fe(ox){sup +} increases faster than that for Al(ox){sup +} to 90{degrees}C.

  10. An unusual cause of acute kidney injury due to oxalate nephropathy in systemic scleroderma.

    Science.gov (United States)

    Mascio, Heather M; Joya, Christie A; Plasse, Richard A; Baker, Thomas P; Flessner, Michael F; Nee, Robert

    2015-08-01

    Oxalate nephropathy is an uncommon cause of acute kidney injury. Far rarer is its association with scleroderma, with only one other published case report in the literature. We report a case of a 75-year-old African-American female with a history of systemic scleroderma manifested by chronic pseudo-obstruction and small intestinal bacterial overgrowth (SIBO) treated with rifaximin, who presented with acute kidney injury with normal blood pressure. A renal biopsy demonstrated extensive acute tubular injury with numerous intratubular birefringent crystals, consistent with oxalate nephropathy. We hypothesize that her recent treatment with rifaximin for SIBO and decreased intestinal transit time in pseudo-obstruction may have significantly increased intestinal oxalate absorption, leading to acute kidney injury. Oxalate nephropathy should be considered in the differential diagnosis of acute kidney injury in scleroderma with normotension, and subsequent evaluation should be focused on bowel function to include alterations in gut flora due to antibiotic administration.

  11. Oxalate nephropathy induced by octreotide treatment for acromegaly: a case report

    Directory of Open Access Journals (Sweden)

    Gariani Karim

    2012-07-01

    Full Text Available Abstract Introduction Oxalate nephropathy has various etiologies and remains a rare cause of renal failure. To the best of our knowledge, we report the first case of oxalate nephropathy following octreotide therapy. Case presentation We report the case of a 78-year-old Caucasian man taking chronic octreotide treatment for acromegaly who presented with acute oxalate nephropathy after antibiotic therapy. The diagnosis was confirmed by urinary analysis and a kidney biopsy. The recovery of renal function was favorable after hydration and withdrawal of octreotide therapy. Conclusions Oxalate nephropathy should be suspected in patients at risk who present with acute kidney injury after prolonged antibiotic treatment. This diagnosis should be distinguished from immuno-allergic interstitial nephritis and requires specific care. The evolution of this condition may be favorable if the pathology is identified correctly. Octreotide therapy should be considered a risk factor for enteric oxaluria.

  12. Stability Constants of Technetium (IV) Oxalate Complexes as a Function of Ionic Strength

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yuanxian; Hess, Nancy J.; Felmy, Andrew R.

    2006-03-01

    Solvent extraction methods were used to determine the stability constants of Tc(IV) with oxalate anions in NaCl solutions ranging in concentration from 0.5 M to 2.0 M. All experiments were conducted in an atmosphere-controlled chamber under Ar atmosphere (< 1.0ppm O2). A reducing agent (hydrazine) was used during extractions to maintain technetium in the tetravalent oxidation state. Independent tests confirmed that the oxidation state of technetium did not change during extractions. The distribution ratio of Tc(IV) between the organic and aqueous phases was found to decrease as the concentration of oxalic acid increased. At the oxalic acid concentrations used in these experiments, the complexes TcO(Ox) and TcO(Ox)22- were found to be the dominant aqueous species. Based on these data, the thermodynamic stability constants of Tc(IV) with oxalate complexes were calculated by the Specific Ion Interaction Theory (SIT).

  13. COFFEE BEAN MYCO-CONTAMINANTS AND OXALIC ACID PRODUCING ASPERGILLUS NIGER

    Directory of Open Access Journals (Sweden)

    Mohamed A. Yassin

    2015-03-01

    Full Text Available Coffee bean-contaminating fungi were determined in random samples collected in Riyadh, Kingdom of Saudi Arabia, using the direct plating technique. Forty-five samples were examined and 12 fungal species belonging to 5 genera were isolated. Aspergillus niger was the most widely distributed and most frequently isolated fungus (86.67%. The ability of the predominant fungus, A. niger, to produce oxalic acid was evaluated using high-performance liquid chromatography. About 50% of the tested A. niger isolates produced oxalic acid; the amount produced was in the range of 90–550 ppm of oxalic acid. Because A. niger was the predominant and most widely distributed toxigenic fungus in the examined samples, more efforts should be directed to minimize the risk of oxalic acid contamination of commoditized coffee beans in the Kingdom of Saudi Arabia.

  14. Effect of Kimchi Fermentation on Oxalate Levels in Silver Beet (Beta vulgaris var. cicla).

    Science.gov (United States)

    Wadamori, Yukiko; Vanhanen, Leo; Savage, Geoffrey P

    2014-04-23

    Total, soluble and insoluble oxalates were extracted and analyzed by high performance liquid chromatography (HPLC) following the preparation of kimchi using silver beet (Beta vulgaris var. cicla) stems and leaves. As silver beet contains high oxalate concentrations and consumption of high levels can cause the development of kidney stones in some people, the reduction of oxalate during preparation and fermentation of kimchi was investigated. The silver beet stems and leaves were soaked in a 10% brine solution for 11 h and then washed in cold tap water. The total, soluble and insoluble oxalate contents of the silver beet leaves were reduced by soaking in brine, from 4275.81 ± 165.48 mg/100 g to 3709.49 ± 216.51 mg/100 g fresh weight (FW). Fermenting the kimchi for 5 days at 19.3 ± 0.8 °C in 5 L ceramic jars with a water airtight seal resulted in a mean 38.50% reduction in total oxalate content and a mean 22.86% reduction in soluble oxalates. The total calcium content was essentially the same before and after the fermentation of the kimchi (mean 296.1 mg/100 g FW). The study showed that fermentation of kimchi significantly (p < 0.05) reduced the total oxalate concentration in the initial mix from 609.32 ± 15.69 to 374.71 ± 7.94 mg/100 g FW in the final mix which led to a 72.3% reduction in the amount of calcium bound to insoluble oxalate.

  15. Aggregation of Calcium Phosphate and Oxalate Phases in the Formation of Renal Stones

    OpenAIRE

    2014-01-01

    The majority of human kidney stones are comprised of multiple calcium oxalate monohydrate (COM) crystals encasing a calcium phosphate nucleus. The physiochemical mechanism of nephrolithiasis has not been well determined on the molecular level; this is crucial to the control and prevention of renal stone formation. This work investigates the role of phosphate ions on the formation of calcium oxalate stones; recent work has identified amorphous calcium phosphate (ACP) as a rapidly forming initi...

  16. Oxalic acid for the control of varroosis in honey bee colonies - a review

    OpenAIRE

    RADEMACHER, Eva; Harz, Marika

    2006-01-01

    International audience; The review summarizes research results on the use of oxalic acid as an acaricide in honey bee colonies. Three different treatment techniques (i.e. trickling, evaporation and spraying) have been developed for the application of oxalic acid. Detailed information is given on the efficacy against Varroa destructor, tolerability by Apis mellifera, protective procedures for the user, residue situation and consumer safety, as well as recommendations for use.

  17. In-cloud oxalate formation in the global troposphere: a 3-D modeling study

    Directory of Open Access Journals (Sweden)

    S. Myriokefalitakis

    2011-01-01

    Full Text Available Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and droplets. Its lifecycle and atmospheric global distribution remain highly uncertain and are the focus of this study. The first global spatial and temporal distribution of oxalate, simulated using a state-of-the-art aqueous phase chemical scheme embedded within the global 3-dimensional chemistry/transport model TM4-ECPL, is here presented. The model accounts for comprehensive gas-phase chemistry and its coupling with major aerosol constituents (including secondary organic aerosol. Model results are consistent with ambient observations of oxalate at rural and remote locations (slope = 0.83 ± 0.06, r2 = 0.67, N = 106 and suggest that aqueous phase chemistry contributes significantly to the global atmospheric burden of secondary organic aerosol. In TM4-ECPL most oxalate is formed in-clouds and less than 10% is produced in aerosol water. About 61% of the oxalate is removed via wet deposition, 35% by in-cloud reaction with hydroxyl radical and 4% by dry deposition. The global oxalate net chemical production is calculated to be about 17–27 Tg yr−1 with almost 91% originating from biogenic hydrocarbons, mainly isoprene. This condensed phase net source of oxalate in conjunction with a global mean turnover time against deposition of about 5 days, maintain oxalate's global tropospheric burden of 0.24–0.39 Tg that is about 13–19% of calculated total organic aerosol burden.

  18. In-cloud oxalate formation in the global troposphere: a 3-D modeling study

    Directory of Open Access Journals (Sweden)

    S. Myriokefalitakis

    2011-06-01

    Full Text Available Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and droplets. Its lifecycle and atmospheric global distribution remain highly uncertain and are the focus of this study. The first global spatial and temporal distribution of oxalate, simulated using a state-of-the-art aqueous-phase chemical scheme embedded within the global 3-dimensional chemistry/transport model TM4-ECPL, is here presented. The model accounts for comprehensive gas-phase chemistry and its coupling with major aerosol constituents (including secondary organic aerosol. Model results are consistent with ambient observations of oxalate at rural and remote locations (slope = 1.16 ± 0.14, r2 = 0.36, N = 114 and suggest that aqueous-phase chemistry contributes significantly to the global atmospheric burden of secondary organic aerosol. In TM4-ECPL most oxalate is formed in-cloud and less than 5 % is produced in aerosol water. About 62 % of the oxalate is removed via wet deposition, 30 % by in-cloud reaction with hydroxyl radical, 4 % by in-cloud reaction with nitrate radical and 4 % by dry deposition. The in-cloud global oxalate net chemical production is calculated to be about 21–37 Tg yr−1 with almost 79 % originating from biogenic hydrocarbons, mainly isoprene. This condensed phase net source of oxalate in conjunction with a global mean turnover time against deposition of about 5 days, maintain oxalate's global tropospheric burden of 0.2–0.3 Tg, i.e. 0.05–0.1 Tg-C that is about 5–9 % of model-calculated water soluble organic carbon burden.

  19. Retinal and choroidal findings in oxalate retinopathy using EDI-OCT.

    Science.gov (United States)

    Roth, Bryan M; Yuan, Alex; Ehlers, Justis P

    2012-01-01

    A 55-year-old woman with extensive retinal crystalline deposition secondary to primary hyperoxaluria presented with bilateral loss of vision secondary to oxalate retinopathy. Enhanced depth imaging optical coherence tomography revealed intraretinal, subretinal, and intraretinal and subretinal pigment epithelium, and choroidal focal hyperreflective structures consistent with both neurosensory and uveal deposition of oxalate crystals. Serial optical coherence tomography revealed continued crystalline deposition with progressive retinal atrophy.

  20. The oxalate-carbonate pathway: at the interface between biology and geology

    Science.gov (United States)

    Junier, P.; Cailleau, G.; Martin, G.; Guggiari, M.; Bravo, D.; Clerc, M.; Aragno, M.; Job, D.; Verrecchia, E.

    2012-04-01

    The formation of calcite in otherwise carbonate-free acidic soils through the biological degradation of oxalate is a mechanism termed oxalate-carbonate pathway. This pathway lies at the interface between biological and geological systems and constitutes an important, although underestimated, soil mineral carbon sink. In this case, atmospheric CO2 is fixed by the photosynthetic activity of oxalogenic plants, which is partly destined to the production of oxalate used for the chelation of metals, and particularly, calcium. Fungi are also able to produce oxalate to cope with elevated concentrations of metals. In spite of its abundance as a substrate, oxalate is a very stable organic anion that can be metabolized only by a group of bacteria that use it as carbon and energy sources. These bacteria close the biological cycle by degrading calcium oxalate, releasing Ca2+ and inducing a change in local soil pH. If parameters are favourable, the geological part of the pathway begins, because this change in pH will indirectly lead to the precipitation of secondary calcium carbonate (calcite) in unexpected geological conditions. Due to the initial acidic soil conditions, and the absence of geological carbonate in the basement, it is unexpected to find C in the form of calcite. The activity of the oxalate-carbonate pathway has now been demonstrated in several places around the world, suggesting that its importance can be even greater than expected. In addition, new roles for each of the biological players of the pathway have been revealed recently forcing us to reconsider a global biogeochemical model for oxalate cycling.

  1. Ability of sat-1 to transport sulfate, bicarbonate, or oxalate under physiological conditions.

    Science.gov (United States)

    Krick, Wolfgang; Schnedler, Nina; Burckhardt, Gerhard; Burckhardt, Birgitta C

    2009-07-01

    Tubular reabsorption of sulfate is achieved by the sodium-dependent sulfate transporter, NaSi-1, located at the apical membrane, and the sulfate-anion exchanger, sat-1, located at the basolateral membrane. To delineate the physiological role of rat sat-1, [(35)S]sulfate and [(14)C]oxalate uptake into sat-1-expressing oocytes was determined under various experimental conditions. Influx of [(35)S]sulfate was inhibited by bicarbonate, thiosulfate, sulfite, and oxalate, but not by sulfamate and sulfide, in a competitive manner with K(i) values of 2.7 +/- 1.3 mM, 101.7 +/- 9.7 microM, 53.8 +/- 10.9 microM, and 63.5 +/- 38.7 microM, respectively. Vice versa, [(14)C]oxalate uptake was inhibited by sulfate with a K(i) of 85.9 +/- 9.5 microM. The competitive type of inhibition indicates that these compounds are most likely substrates of sat-1. Physiological plasma bicarbonate concentrations (25 mM) reduced sulfate and oxalate uptake by more than 75%. Simultaneous application of sulfate, bicarbonate, and oxalate abolished sulfate as well as oxalate uptake. These data and electrophysiological studies using a two-electrode voltage-clamp device provide evidence that sat-1 preferentially works as an electroneutral sulfate-bicarbonate or oxalate-bicarbonate exchanger. In kidney proximal tubule cells, sat-1 likely completes sulfate reabsorption from the ultrafiltrate across the basolateral membrane in exchange for bicarbonate. In hepatocytes, oxalate extrusion is most probably mediated either by an exchange for sulfate or bicarbonate.

  2. Influence of nitrate on oxalate- and glyoxylate-dependent growth and acetogenesis by Moorella thermoacetica.

    Science.gov (United States)

    Seifritz, Corinna; Fröstl, Jürgen M; Drake, Harold L; Daniel, Steven L

    2002-12-01

    Oxalate and glyoxylate supported growth and acetate synthesis by Moorella thermoacetica in the presence of nitrate under basal (without yeast extract) culture conditions. In oxalate cultures, acetate formation occurred concomitant with growth and nitrate was reduced in the stationary phase. Growth in the presence of [(14)C]bicarbonate or [(14)C]oxalate showed that CO(2) reduction to acetate and biomass or oxalate oxidation to CO(2) was not affected by nitrate. However, cells engaged in oxalate-dependent acetogenesis in the presence of nitrate lacked a membranous b-type cytochrome, which was present in cells grown in the absence of nitrate. In glyoxylate cultures, growth was coupled to nitrate reduction and acetate was formed in the stationary phase after nitrate was totally consumed. In the absence of nitrate, glyoxylate-grown cells incorporated less CO(2) into biomass than oxalate-grown cells. CO(2) conversion to biomass by glyoxylate-grown cells decreased when cells were grown in the presence of nitrate. These results suggest that: (1) oxalate-grown cells prefer CO(2) as an electron sink and bypass the nitrate block on the acetyl-CoA pathway at the level of reductant flow and (2) glyoxylate-grown cells prefer nitrate as an electron sink and bypass the nitrate block of the acetyl-CoA pathway by assimilating carbon via an unknown process that supplements or replaces the acetyl-CoA pathway. In this regard, enzymes of known pathways for the assimilation of two-carbon compounds were not detected in glyoxylate- or oxalate-grown cells.

  3. Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the β-lactam producer Penicillium chrysogenum.

    Science.gov (United States)

    Gombert, A K; Veiga, T; Puig-Martinez, M; Lamboo, F; Nijland, J G; Driessen, A J M; Pronk, J T; Daran, J M

    2011-08-01

    Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of ß-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate complicates product recovery. We observed oxalate production in glucose-limited chemostat cultures of P. chrysogenum grown with or without addition of adipic acid, side-chain of the cephalosporin precursor adipoyl-6-aminopenicillinic acid (ad-6-APA). Oxalate accounted for up to 5% of the consumed carbon source. In filamentous fungi, oxaloacetate hydrolase (OAH; EC3.7.1.1) is generally responsible for oxalate production. The P. chrysogenum genome harbours four orthologs of the A. niger oahA gene. Chemostat-based transcriptome analyses revealed a significant correlation between extracellular oxalate titers and expression level of the genes Pc18g05100 and Pc22g24830. To assess their possible involvement in oxalate production, both genes were cloned in Saccharomyces cerevisiae, yeast that does not produce oxalate. Only the expression of Pc22g24830 led to production of oxalic acid in S. cerevisiae. Subsequent deletion of Pc22g28430 in P. chrysogenum led to complete elimination of oxalate production, whilst improving yields of the cephalosporin precursor ad-6-APA.

  4. Renal peroxidative changes mediated by oxalate: the protective role of fucoidan.

    Science.gov (United States)

    Veena, Coothan Kandaswamy; Josephine, Anthony; Preetha, Sreenivasan P; Varalakshmi, Palaninathan; Sundarapandiyan, Rajaguru

    2006-10-04

    Oxalate, one of the major constituents of renal stones is known to induce free radicals which damage the renal membrane. Damaged epithelia might act as nidi for stone formation aggravating calcium oxalate precipitation during hyperoxaluria. In the present study, the beneficial effects of fucoidan on oxalate-induced free radical injury were investigated. Male Wistar rats were divided into four groups. Hyperoxaluria was induced in two groups by administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with fucoidan from Fucus vesiculosus at a dose of 5 mg/kg b.wt subcutaneously commencing from the 8th day of induction. A control and drug control (fucoidan alone) was also included in the study. The extent of renal injury in hyperoxaluria was evident from the increased activities of alkaline phosphatase, gamma-glutamyl transferase, beta-glucuronidase, N-acetyl-beta-D-glucosaminidase in urine. There was a positive correlation between plasma malondialdehyde levels and renal membrane damage indicating a striking relation between free radical formation and cellular injury. Increased protein carbonyl and decreased thiols further exemplified the oxidative milieu prevailing during hyperoxaluria. Decreased renal membrane ATPases accentuated the renal membrane damage induced by oxalate. Renal microscopic analysis showed abnormal findings in histology as an evidence of oxalate damage. The above biochemical and histopathological discrepancies were abrogated with fucoidan administration, indicating its protective role in oxalate mediated peroxidative injury.

  5. Inhibition of crystallization of calcium oxalate by the extraction of Tamarix gallica L.

    Science.gov (United States)

    Bensatal, Ahmed; Ouahrani, M R

    2008-12-01

    The main objective is to study the inhibitor effect of acid fraction of the extract of Tamarix gallica L on the crystallization of calcium oxalate. The extract of Tamarix gallica L is very rich by acid compounds that are used as an inhibitor of nephrolithiasis (calcium oxalate). Our study of the calcium oxalate crystallization is based on the model of turbidimetry by means of a spectrophotometer. The calcium oxalate formation is induced by the addition of oxalate solutions of sodium and of calcium chloride. The addition of inhibitor with various concentrations enabled us to give information on the percentage of inhibition. The comparison between the turbidimetric slopes with and without inhibitor gives the effectiveness of inhibitor for the acid fraction. By comparing the photographs of with and without inhibitor, we concluded that the extract of Tamarix gallica L acts at the stage of growth. The acid fraction of the extract of Tamarix gallica L gives an activity remarkable in the formation of urinary lithiasis (calcium oxalate); this effectiveness is due to the presence of functions of acid.

  6. Characteristic of synergistic extraction of oxalic acid with system from rare earth metallurgical wastewater

    Institute of Scientific and Technical Information of China (English)

    QIU

    2010-01-01

    Large amount of high concentration acidic wastewater would be produced in the conversion process of chloride rare earth into oxide rare earth.It was a mixed solution of oxalic acid and hydrochloric acid,so the recycling use was very difficult.The method of liquid-liquid extraction was proposed in this paper to achieve wastewater treatment and reclamation.The mechanism of extraction of oxalic acid from the wastewater with the systems of 50% TOB+45% kerosene and 5% 2-ethyl hexanol was investigated.The composition and structure of the extracted species and the establishment of the mathematical model of the oxalic acid extraction were determined by the use of saturation method,equimolar series method.The results showed that extraction of oxalic acid by TOB was a neutral association extraction,oxalic acid existed mainly in a molecular form in the organic phase,and the extraction combination ratio was 2:1.The duality extraction system composed of extractant TOB and TOC had synergistic extraction effect on oxalic acid and chlorhydric acid,and the extraction dislribution ratio was improved greatly.The optimum volume fiaction of TOB was 0.6-0.8.

  7. [Study on inhibitory effect of EGCG on Calcium oxalate nephrolithiasis in rats and its related mechanism].

    Science.gov (United States)

    Zhou, Yong; Wang, Shuo; Tang, Chun-bo

    2015-04-01

    In the study, the inhibitory effect of epigallocatechin gallate (EGCG) on Calcium oxalate nephrolithiasis and its possible mechanism were investigated. The rat Calcium oxalate nephrolithiasis model was induced through the combined oral administration of ethylene glycol and ammonium chloride, which was intervened with EGCG. Rat blood samples were collected to detect blood creatinine (Cr), blood urea nitrogen (BUN) and blood calcium. Rat urine samples were collected to observe and compare 24-hour urine volume, oxalic acid (Ox) and calcium in urine. Renal samples were collected to prepare tissue slices and observe the pathological changes in Calcium oxalate nephrolithiasis. The expression of osteopontin (OPN) in renal tissues was evaluated by Real-time PCR and Western blot. According to the results, compared with normal rats, rats in the nephrolithiasis model showed significant increases in Cr, BUN, urine Calcium, urine Ox and renal OPN expression (P nephrolithiasis, those processed with EGCG revealed remarkable declines in Cr, BUN, urine Calcium and urine Ox (P nephrolithiasis rats showed significant pathological changes in Calcium oxalate calculus. After ECCG treatment, the renal pathological changes and OPN expression attenuated significantly in a concentration-dependent manner. The results showed that EGCG inhibits the formation of calcium oxalate nephrolithiasis in rats and shows a notable protective effect on renal functions.

  8. Competitive and Cooperative Effects during Nickel Adsorption to Iron Oxides in the Presence of Oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Elaine D. [Department of Earth and Planetary; Catalano, Jeffrey G. [Department of Earth and Planetary

    2017-08-09

    Iron oxides are ubiquitous in soils and sediments and play a critical role in the geochemical distribution of trace elements and heavy metals via adsorption and coprecipitation. The presence of organic acids may potentially alter how metals associate with iron oxide minerals through a series of cooperative or competitive processes: solution complexation, ternary surface complexation, and surface site competition. The macroscopic and molecular-scale effects of these processes were investigated for Ni adsorption to hematite and goethite at pH 7 in the presence of oxalate. The addition of this organic acid suppresses Ni uptake on both minerals. Aqueous speciation suggests that this is dominantly the result of oxalate complexing and solubilizing Ni. Comparison of the Ni surface coverage to the concentration of free (uncomplexed) Ni2+ in solution suggests that the oxalate also alters Ni adsorption affinity. EXAFS and ATR-FTIR spectroscopies indicate that these changes in binding affinity are due to the formation of Ni–oxalate ternary surface complexes. These observations demonstrate that competition between dissolved oxalate and the mineral surface for Ni overwhelms the enhancement in adsorption associated with ternary complexation. Oxalate thus largely enhances Ni mobility, thereby increasing micronutrient bioavailability and inhibiting contaminant sequestration.

  9. Microstructure and properties of oxalate conversion coating on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    JIANG Yong-feng; ZHOU Hai-tao; ZENG Su-min

    2009-01-01

    The oxalate coating formed on AZ91D magnesium alloy by chemical conversion treatment methods in oxalate salt solutions was investigated.The surface morphologies and chemical composition of coating were examined using scanning electron microscopy (SEM) equipped with energy dispersive analysis of X-ray (EDX).Electrochemical impedance spectroscopy (EIS),potentiodynamic polarization curves and salt spray tests were employed to evaluate corrosion protection of the coating to substrate in 5% NaCl solution.The mechanism of coating formations was also considered in details.The results indicate that a compact and dense surface morphology with fine particle clusters of the oxalate coating on magnesium alloy is presented,which mainly consists of oxide or/and organic of Mg,Al and Zn.And the anti-corrosion of the magnesium after oxalate conversion treatment is better than that of the magnesium substrate.The results of salt spray test for oxalate coating is evaluated as Grade 9 according to ASTM B117.The electric resistance of oxalate chemical conversion coating to substrate is below 0.1Ω.

  10. Urinary excretion of orally administered oxalic acid in saccharin and o-phenylphenol-fed NMRI mice.

    Science.gov (United States)

    Salminen, E; Salminen, S

    1986-01-01

    Both saccharin and o-phenylphenol have been suggested to be carcinogenic to the urinary bladder in experimental animals, but the mechanism has remained unclear. The aim of this study was to investigate the effects of dietary saccharin and o-phenylphenol on the urinary excretion of dietary oxalic acid. Male NMRI mice were gradually adapted to either 3% o-phenylphenol or 5% saccharin in their diet. Having being adapted to these diets for 1 week or after consuming them for 3 months, the animals were fasted for 6 h and given a 2.5-microCi oral dose of U-14C-oxalic acid. Dosed animals were kept in metabolism cages for 48 h to monitor urinary and fecal excretion of the label. Adaptation to dietary o-phenylphenol appeared to increase the urinary excretion of orally administered U-14C-oxalic acid when food and water were available during urinary and fecal collections. Adaptation to dietary saccharin had little effect on urinary oxalate levels when compared to control animals. These results indicate that changes in urinary oxalate levels should be more carefully studied in connection with potential urinary bladder carcinogens to avoid the possibility of bladder irritation by increased urinary oxalate excretion.

  11. Putative Aspergillus niger-induced oxalate nephrosis in sheep : clinical communication

    Directory of Open Access Journals (Sweden)

    C.J. Botha

    2009-05-01

    Full Text Available A sheep farmer provided a maize-based brewer's grain (mieliemaroek and bales of Eragrostis curvula hay to ewes and their lambs, kept on zero-grazing in pens. The 'mieliemaroek' was visibly mouldy. After 14 days in the feedlot, clinical signs, including generalised weakness, ataxia of the hind limbs, tremors and recumbency, were noticed. Six ewes died within a period of 7 days. A post mortem examination was performed on 1 ewe. The carcass appeared to be cachectic with mild effusions into the body cavities; mild lung congestion and pallor of the kidneys were observed. Microscopical evaluation revealed nephrosis and birefringent oxalate crystals in the renal tubules when viewed under polarised light. A provisional diagnosis of oxalate nephrosis with subsequent kidney failure was made. Amongst other fungi, Aspergillus niger was isolated from 'mieliemaroek' samples submitted for fungal culture and identification. As A. niger is known to synthesise oxalates, a qualitative screen to detect oxalic acid in the mieliemaroek and purified A. niger isolates was performed using high-performance liquid chromatography (HPLC. Oxalic acid was detected, which supported a diagnosis of soluble oxalate-induced nephropathy.

  12. Oxalic acid: a signal molecule for fungus-feeding bacteria of the genus Collimonas?

    Science.gov (United States)

    Rudnick, M B; van Veen, J A; de Boer, W

    2015-10-01

    Mycophagous (=fungus feeding) soil bacteria of the genus Collimonas have been shown to colonize and grow on hyphae of different fungal hosts as the only source of energy and carbon. The ability to exploit fungal nutrient resources might require a strategy for collimonads to sense fungi in the soil matrix. Oxalic acid is ubiquitously secreted by soil fungi, serving different purposes. In this study, we investigated the possibility that collimonads might use oxalic acid secretion to localize a fungal host and move towards it. We first confirmed earlier indications that collimonads have a very limited ability to use oxalic acid as growth substrate. In a second step, with using different assays, we show that oxalic acid triggers bacterial movement in such a way that accumulation of cells can be expected at micro-sites with high free oxalic acid concentrations. Based on these observations we propose that oxalic acid functions as a signal molecule to guide collimonads to hyphal tips, the mycelial zones that are most sensitive for mycophagous bacterial attack.

  13. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    Science.gov (United States)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  14. Effect of Oxalic Acid on Potassium Release from Typical Chinese Soils and Minerals

    Institute of Scientific and Technical Information of China (English)

    TU Shu-Xin; GUO Zhi-Fen; SUN Jin-He

    2007-01-01

    Oxalic acid plays an important role in improving the bioavailability of soil nutrients. Batch experiments were employed to examine the influences of oxalic acid on extraction and release kinetics of potassium (K) from soils and minerals along with the adsorption and desorption of soil K+. The soils and minerals used were three typical Chinese soils, black soil (Mollisol), red soil (Ultisol), and calcareous alluvial soil (Entisol), and four K-bearing minerals, biotite, phlogopite, muscovite, and microcline. The results showed that soil K extracted using 0.2 mol L-1 oxalic acid was similar to that using 1 mol L-1 boiling HNO3. The relation between K release (y) and concentrations of oxalic acid (c) could be best described logarithmically as y=a+blogc, while the best-fit kinetic equation of K release was y=a +b√t, where a and b are the constants and t is the elapsed time. The K release for minerals was ranked as biotite> phlogopite>> muscovite> microcline and for soils it was in the order: black soil> calcareous alluvial soil> red soil. An oxalic acid solution with low pH was able to release more K from weathered minerals and alkaline soils. Oxalic acid decreased the soil K+ adsorption and increased the soil K+ desorption, the effect of which tended to be greater at lower solution pH, especially in the red soil.

  15. Oxalate supported pyrolysis of CoTMPP as electrocatalysts for the oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, I. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Institute for Solar Fuel and Energy Storage Materials, Division for Solar Energy Research, Glienicker Strasse 100, D-14109 Berlin (Germany)], E-mail: iris.herrmann@helmholtz-berlin.de; Kramm, U.I.; Fiechter, S.; Bogdanoff, P. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Institute for Solar Fuel and Energy Storage Materials, Division for Solar Energy Research, Glienicker Strasse 100, D-14109 Berlin (Germany)

    2009-07-15

    The utilisation of different metal oxalates in the pyrolysis of cobalt-tetramethoxyphenylporphyrin (CoTMPP) has been investigated as a structure forming agent to obtain highly active electrocatalysts for the oxygen reduction reaction (ORR). Decomposition products of the metal oxalates provide a nano-scaled template for the carbonisation of CoTMPP. After the pyrolysis this template is removed by an etching step so that highly porous carbon-based particles with different morphologies are attained. Thermogravimetric measurements, gas sorption isotherms (BET and pore size distribution), neutron activation analysis (NAA), SEM and XRD analysis examine the pyrolysis process of CoTMPP in the presence of the metal oxalates and the subsequent conditioning step. Thereby, the degree of graphitisation and the morphology of the formed carbon matrix are influenced by the decomposition products of the metal oxalates. Furthermore, the solubility of the decomposition products in the etching step is a crucial factor for the porosity of the final obtained product. Electrochemical analysis (CV and RDE) shows that the catalysts exhibit high kinetic current densities towards the ORR in acidic electrolyte, which is correlated with the contribution of mesopores within the catalyst. Among the investigated metal oxalates, the utilisation of tin oxalate reveals the most beneficial characteristics for the preparation.

  16. REMOVING SLUDGE HEELS FROM SAVANNAH RIVER SITE WASTE TANKS BY OXALIC ACID DISSOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M; David Herman, D; Fernando Fondeur, F; John Pareizs, J; Michael Hay, M; Bruce Wiersma, B; Kim Crapse, K; Thomas Peters, T; Samuel Fink, S; Donald Thaxton, D

    2009-03-01

    The Savannah River Site (SRS) will remove sludge as part of waste tank closure operations. Typically the bulk sludge is removed by mixing it with supernate to produce a slurry, and transporting the slurry to a downstream tank for processing. Experience shows that a residual heel may remain in the tank that cannot be removed by this conventional technique. In the past, SRS used oxalic acid solutions to disperse or dissolve the sludge heel to complete the waste removal. To better understand the actual conditions of oxalic acid cleaning of waste from carbon steel tanks, the authors developed and conducted an experimental program to determine its effectiveness in dissolving sludge, the hydrogen generation rate, the generation rate of other gases, the carbon steel corrosion rate, the impact of mixing on chemical cleaning, the impact of temperature, and the types of precipitates formed during the neutralization process. The test samples included actual SRS sludge and simulated SRS sludge. The authors performed the simulated waste tests at 25, 50, and 75 C by adding 8 wt % oxalic acid to the sludge over seven days. They conducted the actual waste tests at 50 and 75 C by adding 8 wt % oxalic acid to the sludge as a single batch. Following the testing, SRS conducted chemical cleaning with oxalic acid in two waste tanks. In Tank 5F, the oxalic acid (8 wt %) addition occurred over seven days, followed by inhibited water to ensure the tank contained enough liquid to operate the mixer pumps. The tank temperature during oxalic acid addition and dissolution was approximately 45 C. The authors analyzed samples from the chemical cleaning process and compared it with test data. The conclusions from the work are: (1) Oxalic acid addition proved effective in dissolving sludge heels in the simulant demonstration, the actual waste demonstration, and in SRS Tank 5F. (2) The oxalic acid dissolved {approx} 100% of the uranium, {approx} 100% of the iron, and {approx} 40% of the manganese

  17. Downscaled anodic oxidation process for aluminium in oxalic acid

    Science.gov (United States)

    Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A.; Lampke, T.

    2017-03-01

    The increasing multi-functionality of parts and assemblies in several fields of engineering demands, amongst others, highly functionalised surfaces. For the different applications, on the one hand, there is a need to scale up surface modification processes originating in the nano- and micro-scale. On the other hand, conventional macro-scale surface refinement methods offer a huge potential for application in the said nano- and micro-scale. The anodic oxidation process, which is established especially for aluminium and its alloys, allows the formation of oxide ceramic layers on the surface. The build-up of an oxide ceramic coating comes along with altered chemical, tribological and electrical surface properties. As a basis for further investigations regarding the use of the anodic oxidation process for micro-scale-manufacturing, the scale effects of oxalic acid anodising on commercially pure aluminium as well as on the AlZn5.5MgCu alloy are addressed in the present work. The focus is on the amount of oxide formed during a potentiostatic process in relation to the exchanged amount of charge. Further, the hardness of the coating as an integral measure to assess the porous oxide structure is approached by nano-indentation technique.

  18. Isolation of americium (5) oxalate compounds from solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zubarev, V.G.; Krot, N.N.

    1982-01-01

    Certain conditions of americium (5) isolation with solutions of ammonia and KOH are studied as well as the attitude of hydroxide obtained to heating. Like neptunium (5) hydroxide americium (5) hydroxide probably has the formula AmO/sub 2/OHxxH/sub 2/O, where x is approximately equal to 2.3. It is established that during heating in the air up to 120 deg C hydroxide transforms into AmO/sub 2/. It is shown that in solutions with a high concentration of oxalate-ion americium stability in oxidation state +5 depends greatly on the pH of solution. Complex salts KAmO/sub 2/C/sub 2/O/sub 4/xxH/sub 2/O and CsAmO/sub 2/C/sub 2/O/sub 4/xxH/sub 2/O are synthesized. The identification is made according to the method of preparation and results of analysis of C/sub 2/O/sub 4//sup 2 -/: AmO/sub 2//sup +/ ratio. It is found that the salts are non-isomorphous to similar salts of pentavalent neptunium. CsAmO/sub 2/C/sub 2/O/sub 4/xxH/sub 2/O is identified in cubic crystal system with the lattice constant a=1.25 nm.

  19. Hydrogen bond patterns in 3-carboxypiperidinium semi-oxalate monohydrate

    Directory of Open Access Journals (Sweden)

    Lusbely M. Belandria

    2013-05-01

    Full Text Available The crystal structure of compound C6H12NO2·C2HO4·H2O, or NIPE·OXAL·HYDR, is an ionic ensemble assisted by hydrogen bonds established between NIPE+ cations, OXAL− semi-oxalate anions and water molecules.The molecules are connected by O--H···O and N--H···O hydrogen bonds, forming linear ∙∙∙semi-oxalate∙∙∙semi-oxalate∙∙∙ chains extending along the a axis and described by the graph-set motif C(5. These chains interact with the NH2+ group of NIPE+ and the water molecules building a two-dimensional crystal packing of rings described by graph-set R21(5, R24(8 and R55(19, with corrugated layers running parallel to the (001 plane, and separated by hydrophobic interactions at c/2. Analyzes of the structures of the individual components and the hydrogen-bond network of the crystal structure are given.

  20. Effect of different brewing times on soluble oxalate content of loose-packed black teas and tea bags.

    Science.gov (United States)

    Mahdavi, Reza; Lotfi Yagin, Neda; Liebman, Michael; Nikniaz, Zeinab

    2013-02-01

    Because of the postulated role of increased dietary oxalate intake in calcium oxalate stone formation, the effect of different brewing times on soluble oxalate contents of loose-packed black tea and tea bags was studied. The oxalate content of 25 different samples of loose-packed black teas after brewing at 5, 10, 15, 30, and 60 min and of ten brands of tea bags after infusion for 1, 2, 3, 4, and 5 min was measured by enzymatic assay. The oxalate concentration resulting from different brewing times ranged from 4.3 to 6.2 mg/240 ml for loose-packed black teas and from 2.7 to 4.8 mg/240 ml for tea bags. There was a stepwise increase in oxalate concentration associated with increased brewing times.

  1. Nanoscale observations of the effect of citrate on calcium oxalate precipitation on calcite surfaces.

    Science.gov (United States)

    Burgos-Cara, Alejandro; Ruiz-Agudo, Encarnacion; Putnis, Christine V.

    2016-04-01

    Calcium oxalate (CaC2O4ṡxH2O) minerals are naturally occurring minerals found in fossils, plants, kidney stones and is a by-product in some processes such as paper, food and beverage production [1,2]. In particular, calcium oxalate monohydrate phase (COM) also known as whewellite (CaC2O4ṡH2O), is the most frequently reported mineral phase found in urinary and kidney stones together with phosphates. Organic additives are well known to play a key role in the formation of minerals in both biotic and abiotic systems, either facilitating their precipitation or hindering it. In this regard, recent studies have provided direct evidence demonstrating that citrate species could enhance dissolution of COM and inhibit their precipitation. [3,4] The present work aims at evauate the influence of pH, citrate and oxalic acid concentrations in calcium oxalate precipitation on calcite surfaces (Island Spar, Chihuahua, Mexico) through in-situ nanoscale observation using in situ atomic force microscopy (AFM, Multimode, Bruker) in flow-through experiments. Changes in calcium oxalate morphologies and precipitated phases were observed, as well as the inhibitory effect of citrate on calcium oxalate precipitation, which also lead to stabilization an the amorphous calcium oxalate phase. [1] K.D. Demadis, M. Öner, Inhibitory effects of "green"additives on the crystal growth of sparingly soluble salts, in: J.T. Pearlman (Ed.), Green Chemistry Research Trends, Nova Science Publishers Inc., New York, 2009, pp. 265-287. [2] M. Masár, M. Zuborová, D. Kaniansky, B. Stanislawski, Determination of oxalate in beer by zone electrophoresis on a chip with conductivity detection, J. Sep. Sci. 26 (2003) 647-652. [3] Chutipongtanate S, Chaiyarit S, Thongboonkerd V. Citrate, not phosphate, can dissolve calcium oxalate monohydrate crystals and detach these crystals from renal tubular cells. Eur J Pharmacol 2012;689:219-25. [4] Weaver ML, Qiu SR, Hoyer JR, Casey WH, Nancollas GH, De Yoreo JJ

  2. Inhibition of the Crystal Growth and Aggregation of Calcium Oxalate by Algae Sulfated Polysaccharide In-vitro

    Institute of Scientific and Technical Information of China (English)

    Xiu Mei WU; Jian Ming OUYANG; Sui Ping DENG; Ying Zhou CEN

    2006-01-01

    The influence of sulfated polysaccharide (SPS) isolated from marine algae Sargassum fusiforme on the morphology and phase compositions of urinary crystal calcium oxalate was investigated in vitro by means of scanning electron microscopy and X-ray diffraction. SPS maybe is a potential inhibitor to CaOxa urinary stones by inhibiting the growth of calcium oxalate monohydrate (COM), preventing the aggregation of COM, and inducing the formation of calcium oxalate dihydrate (COD) crystals.

  3. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid

    Science.gov (United States)

    Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae

    2016-01-01

    Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease. PMID:27258452

  4. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid.

    Directory of Open Access Journals (Sweden)

    Ja Yeong Jang

    Full Text Available Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS. Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10% and oxalic acid-WP8 (ai 8%, were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate. These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.

  5. The role of intestinal oxalate transport in hyperoxaluria and the formation of kidney stones in animals and man.

    Science.gov (United States)

    Whittamore, Jonathan M; Hatch, Marguerite

    2017-02-01

    The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal pathway for elimination of this waste metabolite. Knowledge of the mechanisms responsible for oxalate absorption and secretion by the intestine therefore have significant implications for understanding the etiology of hyperoxaluria, as well as offering potential targets for future treatment strategies for calcium oxalate kidney stone disease. In this review, we present the recent developments and advances in this area over the past 10 years, and put to the test some of the new ideas that have emerged during this time, using human and mouse models. A key focus for our discussion are the membrane-bound anion exchangers, belonging to the SLC26 gene family, some of which have been shown to participate in transcellular oxalate absorption and secretion. This has offered the opportunity to not only examine the roles of these specific transporters, revealing their importance to oxalate homeostasis, but to also probe the relative contributions made by the active transcellular and passive paracellular components of oxalate transport across the intestine. We also discuss some of the various physiological stimuli and signaling pathways which have been suggested to participate in the adaptation and regulation of intestinal oxalate transport. Finally, we offer an update on research into Oxalobacter formigenes, alongside recent investigations of other oxalate-degrading gut bacteria, in both laboratory animals and humans.

  6. Synthesis of calcium oxalate crystals in culture medium irradiated with non-equilibrium atmospheric-pressure plasma

    Science.gov (United States)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Mizuno, Masaaki; Yamanishi, Yoko; Hori, Masaru

    2016-09-01

    Octahedral particulates several tens of microns in size were synthesized in a culture medium irradiated through contact with a plume of non-equilibrium atmospheric-pressure plasma (NEAPP). The particulates were identified in the crystalline phase as calcium oxalate dihydrate (COD). The original medium contained constituents such as NaCl, d-glucose, CaCl2, and NaHCO3 but not oxalate or oxalic acid. The oxalate was clearly synthesized and crystallized in the medium as thermodynamically unstable COD crystals after the NEAPP irradiation.

  7. Factors affecting calcium oxalate dihydrate fragmented calculi regrowth

    Directory of Open Access Journals (Sweden)

    Sanchis P

    2006-07-01

    Full Text Available Abstract Background The use of extracorporeal shock wave lithotripsy (ESWL to treat calcium oxalate dihydrate (COD renal calculi gives excellent fragmentation results. However, the retention of post-ESWL fragments within the kidney remains an important health problem. This study examined the effect of various urinary conditions and crystallization inhibitors on the regrowth of spontaneously-passed post-ESWL COD calculi fragments. Methods Post-ESWL COD calculi fragments were incubated in chambers containing synthetic urine varying in pH and calcium concentration: pH = 5.5 normocalciuria (3.75 mM, pH = 5.5 hypercalciuria (6.25 mM, pH = 6.5 normocalciuria (3.75 mM or pH = 6.5 hypercalciuria (6.25 mM. Fragment growth was evaluated by measuring increases in weight. Fragment growth was standardized by calculating the relative mass increase. Results Calcium oxalate monohydrate (COM crystals formed on COD renal calculi fragments under all conditions. Under pH = 5.5 normocalciuria conditions, only COM crystals formed (growth rate = 0.22 ± 0.04 μg/mg·h. Under pH = 5.5 hypercalciuria and under pH = 6.5 normocalciuria conditions, COM crystals and a small number of new COD crystals formed (growth rate = 0.32 ± 0.03 μg/mg·h and 0.35 ± 0.05 μg/mg·h, respectively. Under pH = 6.5 hypercalciuria conditions, large amounts of COD, COM, hydroxyapatite and brushite crystals formed (growth rate = 3.87 ± 0. 34 μg/mg·h. A study of three crystallization inhibitors demonstrated that phytate completely inhibited fragment growth (2.27 μM at pH = 5.5 and 4.55 μM at pH = 6.5, both under hypercalciuria conditions, while 69.0 μM pyrophosphate caused an 87% reduction in mass under pH = 6.5 hypercalciuria conditions. In contrast, 5.29 mM citrate did not inhibit fragment mass increase under pH = 6.5 hypercalciuria conditions. Conclusion The growth rate of COD calculi fragments under pH = 6.5 hypercalciuria conditions was approximately ten times that observed under

  8. Origin and types of calcium oxalate monohydrate papillary renal calculi.

    Science.gov (United States)

    Grases, Fèlix; Costa-Bauzá, Antonia; Gomila, Isabel; Conte, Antonio

    2010-12-01

    Subepithelial hydroxyapatite calcification of renal papilla is thought to be involved in the formation of calcium oxalate monohydrate (COM) papillary calculi. To assess the mechanism of formation, we sought to correlate the fine structure of papillary renal calculi with specific pathophysiologic conditions and urinary alterations. The study included 831 COM papillary renal calculi with established fine inner structures. A total of 24 patients with chronic stone formation were randomly selected, and their urine was collected and analyzed. The case history and lifestyle habits of these patients were obtained. The 831 papillary calculi could be classified into 1 of 4 main groups. Type I included small calculi in which COM columnar crystals begin to develop in the concave zone in close contact with papillary tissue. Type II calculi contained a hydroxyapatite core located in or near the concave zone. Type III consisted of calculi that developed on the tip of the papillae and in the concave zone, containing hydroxyapatite, calcified tissue, and calcified tubules. Type IV consisted of papillary calculi in which the core, which is situated near, but not in, the concave zone, is formed by intergrown COM crystals and organic matter. Many factors, including urinary alterations (eg, hyperoxaluria), associated diseases (eg, hypertension, diabetes), and consumption or exposure to cytotoxic substances (eg, analgesic abuse) were associated with these types of calculi. Our findings have indicated that injury is the first cause of papillary COM calculus formation, with the location of the injury determining the morphology of the resulting calculus. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. ENHANCED CHEMICAL CLEANING: EFFECTIVENESS OF THE UV LAMP TO DECOMPOSE OXALATES

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Huff, T.; Sudduth, C.

    2010-01-19

    Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

  10. ENHANCED CHEMICAL CLEANING: EFFECTIVENESS OF THE UV LAMP TO DECOMPOSE OXALATES

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Huff, T.; Sudduth, C.

    2010-01-19

    Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

  11. Smad signaling pathway in pathogenesis of kidney injury induced by calcium oxalate stone in rats

    Institute of Scientific and Technical Information of China (English)

    Fan Zhang

    2016-01-01

    Objective:To investigate the involvement of Smad signaling pathway in the pathogenesis of kidney injury induced by calcium oxalate stone in rats to provide a reference for clinical treatment.Methods: Clean SD rats were randomly divided into 3 group, namely the control group, model group and pirfenidone group. Ethylene glycol + αhydroxy vitamin D3 was used as a stone-inducing agent to replicate the renal calcium oxalate stone model. Rats in the pirfenidone group were treated with pirfenidone intragastric administration. The serum Cr, BUN and 24-hour oxalate and calcium in renal tissues were assayed. The expressions of Bax/Bcl2 protein, Caspase3 protein, TGFβ, Smad1, Smad2 and Smad3 proteins were detected by the fluorescent quantitation PCR method.Results:Compared with the rats of the control group, the results showed that the levels of serum BUN, Cr and 24-hour oxalate in rats of the model group were increased greatly,BaxandCaspase3 mRNA also increased while the level ofBcl2 decreased significantly, and the expressions of TGFβ, Smad1, Smad2 and Smad3 proteins increased distinctly as well (P<0.01). These abnormal parameters could be normalized effectively by pirfenidone.Conclusions:Activated TGFβ/Smad signaling pathway is involved in the pathogenesis of kidney injury induced by calcium oxalate stone in rats.

  12. Corrosion Behavior of Alloy 22 in Oxalic Acid and Sodium Chloride Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Day, S D; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-06-24

    Nickel based Alloy 22 (NO6022) is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in oxalic acid solution and to compare its behavior to sodium chloride (NaCl) solutions. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion rate of Alloy 22 in oxalic acid solutions increased rapidly as the temperature and the acid concentration increased. Extrapolation studies show that even at a concentration of 10{sup -4}M oxalic acid, the corrosion rate of Alloy 22 would be higher in oxalic acid than in 1 M NaCl solution. Alloy 22 was not susceptible to localized corrosion in oxalic acid solutions. Cyclic polarization tests in 1 M NaCl showed that Alloy 22 was susceptible to crevice corrosion at 90 C but was not susceptible at 60 C.

  13. Growth and characterization of Sm3+ doped cerium oxalate single crystals

    Directory of Open Access Journals (Sweden)

    Minu Mary C

    2016-07-01

    Full Text Available Single crystals of Sm3+ doped cerium oxalate decahydrate were synthesized using single diffusion gel technique and the conditions influencing the size, morphology, nucleation density and quality of the crystals were optimized. Highly transparent single crystals of average size 3 mm × 2 mm × 1 mm with well-defined hexagonal morphology were grown during a time period of two weeks. X-ray powder diffraction analysis revealed that the grown crystals crystallize in the monoclinic system with space group P21/c as identical with the pure cerium oxalate. The various functional groups of the oxalate ligand and the water of crystallization were identified by Fourier transform infrared spectroscopy. The photoluminescence spectrum of the Sm3+ doped cerium oxalate indicated that the Sm3+ ions are optically active in the cerium oxalate matrix. The crystal has a strong and efficient orange red emission with a wavelength peak at 595 nm and hence can be effectively used for optical amplification. Microhardness measurements of the crystal revealed that they belong to the soft material category.

  14. 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.

  15. Calcium oxalate crystallization index (COCI): an alternative method for distinguishing nephrolithiasis patients from healthy individuals.

    Science.gov (United States)

    Yang, Bowei; Dissayabutra, Thasinas; Ungjaroenwathana, Wattanachai; Tosukhowong, Piyaratana; Srisa-Art, Monpichar; Supaprom, Thavorn; Insin, Numpon; Boonla, Chanchai

    2014-01-01

    Urinary supersaturation triggers lithogenic crystal formation. We developed an alternative test, designated calcium oxalate crystallization index (COCI), to distinguish nephrolithiasis patients from healthy individuals based on their urinary crystallization capability. The effect of urine volume, oxalate, phosphate, citrate, potassium, and sodium on COCI values was investigated. COCI values were determined in 24-hr urine obtained from nephrolithiasis patients (n=72) and matched healthy controls (n=71). Increases in urine oxalate and phosphate and decreases in urine volume and citrate resulted in significantly increased COCI values. The urinary COCI in nephrolithiasis patients was significantly higher than that in healthy individuals. Two healthy subjects who had elevated COCI values were found to have asymptomatic kidney calculi. The receiver operating characteristic analysis showed an area under the curve of the urinary COCI test of 0.9499 (95%CI: 0.9131-0.9868) for distinguishing between nephrolithiasis and healthy subjects. At the cutoff of 165 mg oxalate equivalence/day, the urinary COCI test provided sensitivity, specificity, and accuracy amounts of 83.33%, 97.18%, and 90.21%, respectively. Urinary COCI values were primarily dependent on urine volume, oxalate, and phosphate. The test provided high sensitivity and specificity for clinically discriminating nephrolithiasis patients from healthy controls. It might be used to detect individuals with asymptomatic kidney calculi.

  16. Pathological features of oxalate nephrosis in a population of koalas (Phascolarctos cinereus) in South Australia.

    Science.gov (United States)

    Speight, K N; Boardman, W; Breed, W G; Taggart, D A; Woolford, L; Haynes, J I

    2013-03-01

    The wild and captive koala population of the Mt Lofty Ranges in South Australia has a high level of renal dysfunction in which crystals consistent with calcium oxalate have been observed in the kidneys. This study aimed to describe the pathological features of the renal disease in this population, confirm the composition of renal crystals as calcium oxalate, and determine whether any age or sex predispositions exist for this disease. A total of 51 koalas (28 wild rescues, 23 captive) were examined at necropsy, of which 28 (55%) were found to have gross and/or histological evidence of oxalate nephrosis. Histopathological features included intratubular and interstitial inflammation, tubule dilation, glomerular atrophy, tubule loss, and cortical fibrosis. Calcium oxalate crystals were demonstrated using a combination of polarization microscopy, alizarin red S staining, infrared spectroscopy, and energy-dispersive X-ray analysis with scanning electron microscopy. Uric acid and phosphate deposits were also shown to be present but were associated with minimal histopathological changes. No significant differences were found between the numbers of affected captive and wild rescued koalas; also, there were no sex or age predispositions identified, but it was found that oxalate nephrosis may affect koalas koala population. Possible causes of this disease are currently under investigation.

  17. Synthesis and spectroscopic investigation of nanostructured europium oxalate: A potential red emitting phosphor

    Science.gov (United States)

    Vimal, G.; Mani, K. P.; Biju, P. R.; Joseph, C.; Unnikrishnan, N. V.; Ittyachen, M. A.

    2015-10-01

    Nanostructured europium oxalate was successfully synthesized for the first time by microwave assisted co-precipitation method. Structure and nanocrystalline nature of the synthesized europium oxalate was analyzed using X-ray diffraction and the results were confirmed by transmission electron microscopy. Fourier transform infrared spectroscopy was employed to identify the different functional groups present in the nanostructured europium oxalate. Detailed spectroscopic investigations were carried out using Judd-Ofelt theory to find out the spectroscopic parameters of europium oxalate. Nature of the metal-ligand bond and symmetry of the environment around Eu3+ ions, which strongly influences the luminescence characteristics of the material, were analyzed. Photoluminescence emission spectrum of the material confirmed the strong red emission predicted by the JO theoretical analysis which is further ascertained by CIE chromaticity diagram. Further analysis on the luminescence parameters such as life time, quantum efficiency and color purity of nanostructured europium oxalate revealed the suitability of this material as a potential phosphor for red emission.

  18. Effects of surface coordination on the temperature-programmed desorption of oxalate from goethite

    Energy Technology Data Exchange (ETDEWEB)

    Boily, Jean F.; Szanyi, Janos; Felmy, Andrew R.

    2007-11-15

    The temperature-programmed desorption (TPD) of weakly-bound, hydrogen-bonded and metal-bonded oxalate complexes at the goethite surface was investigated in the 300-900 K range with concerted Fourier Transform Infrared (FTIR) measurements (TPD-FTIR). These reactions took place with the concomitant dehydroxylation reaction of goethite to hematite and decarbonation of bulk-occluded carbonate. The measurements revealed three important stages of desorption. Stage I (300-440 K) corresponds to the desorption of weakly-and/or un-bound oxalate molecules in the goethite powder with a thermal decomposition reaction pathway characteristic of oxalic acid. Stage II (440-520 K) corresponds to a thermally-driven dehydration of hydrogen-bonded surface complexes, leading to a partial desorption via oxalic acid thermal decomposition pathways and to a partial conversion to metal-bonded surface complexes. This latter mechanism led to the increase in FTIR bands characteristic of these complexes. Finally, Stage III (520-660 K) corresponds to the thermal decomposition of the metal-bonded oxalate complex, proceeding through a 2 electron reduction pathway.

  19. SAVANNAH RIVER SITE TANK CLEANING: CORROSION RATE FOR ONE VERSUS EIGHT PERCENT OXALIC ACID SOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Subramanian, K.

    2011-01-20

    Until recently, the use of oxalic acid for chemically cleaning the Savannah River Site (SRS) radioactive waste tanks focused on using concentrated 4 and 8-wt% solutions. Recent testing and research on applicable dissolution mechanisms have concluded that under appropriate conditions, dilute solutions of oxalic acid (i.e., 1-wt%) may be more effective. Based on the need to maximize cleaning effectiveness, coupled with the need to minimize downstream impacts, SRS is now developing plans for using a 1-wt% oxalic acid solution. A technology gap associated with using a 1-wt% oxalic acid solution was a dearth of suitable corrosion data. Assuming oxalic acid's passivation of carbon steel was proportional to the free oxalate concentration, the general corrosion rate (CR) from a 1-wt% solution may not be bound by those from 8-wt%. Therefore, after developing the test strategy and plan, the corrosion testing was performed. Starting with the envisioned process specific baseline solvent, a 1-wt% oxalic acid solution, with sludge (limited to Purex type sludge-simulant for this initial effort) at 75 C and agitated, the corrosion rate (CR) was determined from the measured weight loss of the exposed coupon. Environmental variations tested were: (a) Inclusion of sludge in the test vessel or assuming a pure oxalic acid solution; (b) acid solution temperature maintained at 75 or 45 C; and (c) agitation of the acid solution or stagnant. Application of select electrochemical testing (EC) explored the impact of each variation on the passivation mechanisms and confirmed the CR. The 1-wt% results were then compared to those from the 8-wt%. The immersion coupons showed that the maximum time averaged CR for a 1-wt% solution with sludge was less than 25-mils/yr for all conditions. For an agitated 8-wt% solution with sludge, the maximum time averaged CR was about 30-mils/yr at 50 C, and 86-mils/yr at 75 C. Both the 1-wt% and the 8-wt% testing demonstrated that if the sludge was removed

  20. Oxalic acid as a heterogeneous ice nucleus in the upper troposphere and its indirect aerosol effect

    Directory of Open Access Journals (Sweden)

    B. Zobrist

    2006-05-01

    Full Text Available Heterogeneous ice freezing points of aqueous solutions containing various immersed solid dicarboxylic acids (oxalic, adipic, succinic, phthalic and fumaric have been measured with a differential scanning calorimeter. The results show that only the dihydrate of oxalic acid (OAD acts as a heterogeneous ice nucleus, with an increase in freezing temperature between 2-5 K depending on solution composition. In several field campaigns, oxalic acid enriched particles have been detected in the upper troposphere with single particle aerosol mass spectrometry. Simulations with a microphysical box model indicate that the presence of OAD may reduce the ice particle number density in cirrus clouds by up to ~50% when compared to exclusively homogeneous cirrus formation without OAD. Using the ECHAM4 climate model we estimate the global net radiative effect caused by this heterogeneous freezing to result in a cooling as high as -0.3 Wm-2.

  1. Thermal, FT–IR and dielectric studies of gel grown sodium oxalate single crystals

    Indian Academy of Sciences (India)

    B B Parekh; P M Vyas; Sonal R Vasant; M J Joshi

    2008-04-01

    Oxalic acid metabolism is important in humans, animals and plants. The effect of oxalic acid sodium salt is widely studied in living body. The growth of sodium oxalate single crystals by gel growth is reported, which can be used to mimic the growth of crystals in vivo. The grown single crystals are colourless, transparent and prismatic. The crystals have been characterized by thermogravimetric analysis, FT–IR spectroscopy and dielectric response at various frequencies of applied field. The crystals become anhydrous at 129.3°C. Coats and Redfern relation is applied to evaluate the kinetic and thermodynamic parameters of dehydration. The dielectric study suggests very less variation of dielectric constant with frequency of applied field in the range of 1 kHz–1 MHz. The nature of variation of imaginary part of complex permittivity, dielectric loss and a.c. resistivity with applied frequency has been reported.

  2. Electrochemical Oxidation and Determination of Oxalic Acid at an Exfoliated Graphite-Polystyrene Composite Electrode

    Directory of Open Access Journals (Sweden)

    Joop Schoonman

    2007-04-01

    Full Text Available An exfoliated graphite-polystyrene composite electrode was evaluated as analternative electrode in the oxidation and the determination of oxalic acid in 0.1 M Na2SO4supporting electrolyte. Using CV, LSV, CA procedures, linear dependences I vs. C wereobtained in the concentrations range of oxalic acid between 0.5 to 3 mM, with LOD =0.05mM, and recovery degree of 98%, without need of surface renewing between successiveruns. The accuracy of the methods was evaluated as excellent comparing the detection resultswith that obtained using conventional KMnO4 titration method. In addition, the apparentdiffusion coefficient of oxalic acid D was found to be around 2.89 · 10-8 cm2·s-1 by CA andCV.

  3. Stannous oxalate: An efficient catalyst for poly(trimethylene terephthalate) synthesis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.

  4. [Contents of tannins and oxalic acid in the selected forest fruits depending on the harvest site].

    Science.gov (United States)

    Sembratowicz, Iwona; Ognik, Katarzyna; Rusinek, Elzbieta; Truchliński, Jerzy

    2008-01-01

    Contents of anti-nutritional components (tannins and oxalic acid) were determined in samples of forest fruits: blueberry, raspberry and wild strawberry harvested in Lublin region from areas considered as potentially not exposed to pollution (Skierbieszów Landscape Park) and potentially polluted areas (Cement Factory Rejowiec S.A.). Study revealed that blueberry and raspberry fruits collected on potentially polluted area were characterized by higher tannins contents than those harvested on potentially not polluted area. Oxalic acid level in studied material indicated its significantly higher concentration in wild strawberry fruits collected both from not exposed and polluted areas as compared to raspberry and blueberry. Tannins and oxalic acid contents in analyzed berries may be accepted as low and safe for human's health.

  5. Acute oxalate nephropathy associated with orlistat: a case report with a review of the literature.

    Science.gov (United States)

    Chaudhari, Dhara; Crisostomo, Conchitina; Ganote, Charles; Youngberg, George

    2013-01-01

    Orlistat is a gastrointestinal lipase inhibitor used for weight reduction in obese individuals. Enteric hyperoxaluria caused by orlistat leads to oxalate absorption. Acute oxalate nephropathy is a rare complication of treatment with orlistat. Herein we report a patient presenting with acute renal failure which improved minimal with intravenous hydration. She was found to have oxalate crystals on renal biopsy. Patient admitted orlistat use over the counter for weight reduction on further questioning. The purpose of this case review is to increase awareness among patients since they are more focused on losing weight. This case also calls for the provider attention to educate patients regarding side effects of orlistat because of easy availability of orlistat over the counter.

  6. Acute Oxalate Nephropathy Associated with Orlistat: A Case Report with a Review of the Literature

    Directory of Open Access Journals (Sweden)

    Dhara Chaudhari

    2013-01-01

    Full Text Available Orlistat is a gastrointestinal lipase inhibitor used for weight reduction in obese individuals. Enteric hyperoxaluria caused by orlistat leads to oxalate absorption. Acute oxalate nephropathy is a rare complication of treatment with orlistat. Herein we report a patient presenting with acute renal failure which improved minimal with intravenous hydration. She was found to have oxalate crystals on renal biopsy. Patient admitted orlistat use over the counter for weight reduction on further questioning. The purpose of this case review is to increase awareness among patients since they are more focused on losing weight. This case also calls for the provider attention to educate patients regarding side effects of orlistat because of easy availability of orlistat over the counter.

  7. Decreased renal vitamin K-dependent γ-glutamyl carboxylase activity in calcium oxalate calculi patients

    Institute of Scientific and Technical Information of China (English)

    陈俊汇; 刘继红; 章咏裳; 叶章群; 王少刚

    2003-01-01

    Objective To study the activity of vitamin K-dependent γ-glutamyl carboxylase in patients with calcium oxalate (CaOx) urolithiasis compared with healthy individuals and to assess its relationship to the renal calcium oxalate urolithiasis. Methods Renal parenchymas were harvested from urolithic patients and renal tumor patients undergoing nephrectomy. The renal carboxylase activity was evaluated as the radioactivity of [14C] labeled sodium bicarbonate in carboxylic reactions in vitro using β-liquid scintillation counting. Results Significantly reduced activity of renal vitamin K-dependent γ-glutamyl carboxylase was observed in the urolithic group as compared with normal controls (P<0.01). Conclusion It suggests that the reduced carboxylase activity observed in the urolithic patients may play an important role in the course of renal calcium oxalate urolithiasis.

  8. [Effect of lectins from Azospirillum brasilense to peroxidase and oxalate oxidase activity regulation in wheat roots].

    Science.gov (United States)

    Alen'kina, S A; Nikitina, V E

    2010-01-01

    Lectins were extracted from the surface of nitrogen-fixing soil bacteria Azospirillum brasilense Sp7 and from its mutant A. brasilense Sp7.2.3 defective in lectin activity. The ability oflectins to stimulate the rapid formation of hydrogen peroxide related to increase of oxalate oxidase and peroxidase activity in the roots of wheat seedlings has been demonstrated. The most rapid induced pathway of hydrogen peroxide formation in the roots of wheat seedlings was the oxalic acid oxidation by oxalate oxidase which is the effect oflectin in under 10 min in a concentration of 10 microg/ml. The obtained results show that lectins from Azospirillum are capable of inducing the adaptation processes in the roots of wheat seedlings.

  9. Hydrothermal decomposition of actinide(IV oxalates: a new aqueous route towards reactive actinide oxide nanocrystals

    Directory of Open Access Journals (Sweden)

    Walter Olaf

    2016-01-01

    Full Text Available The hydrothermal decomposition of actinide(IV oxalates (An= Th, U, Pu at temperatures between 95 and 250 °C is shown to lead to the production of highly crystalline, reactive actinide oxide nanocrystals (NCs. This aqueous process proved to be quantitative, reproducible and fast (depending on temperature. The NCs obtained were characterised by X-ray diffraction and TEM showing their size to be smaller than 15 nm. Attempts to extend this general approach towards transition metal or lanthanide oxalates failed in the 95–250 °C temperature range. The hydrothermal decomposition of actinide oxalates is therefore a clean, flexible and powerful approach towards NCs of AnO2 with possible scale-up potential.

  10. Stability-indicating RP-HPLC method for the simultaneous determination of escitalopram oxalate and clonazepam.

    Science.gov (United States)

    Kakde, Rajendra B; Satone, Dinesh D; Gadapayale, Kamalesh K; Kakde, Megha G

    2013-07-01

    The objective of the current study was to develop a validated, specific stability-indicating reversed-phase liquid chromatographic (LC) method for the quantitative determination of escitalopram oxalate and clonazepam and their related substances in bulk drugs and pharmaceutical dosage forms in the presence of degradation products. Forced degradation studies were performed on the pure drugs of escitalopram oxalate and clonazepam, as per the stress conditions prescribed by the International Conference on Harmonization (ICH) using acid, base, oxidation, thermal stress and photolytic degradation to show the stability-indicating power of the method. Significant degradation was observed during acid and alkaline hydrolysis and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies. Good resolution between the peaks corresponded to the active pharmaceutical ingredients, escitalopram oxalate and clonazepam, and degradation products from the analyte were achieved on an ODS Hypersil C18 column (250 × 4.6 mm) using a mobile phase consisting of a mixture of acetonitrile-50 mM phosphate buffer + 10 mM triethylamine (70:30, v/v). The detection was conducted at 268 nm. The limit of detection and the limit of quantitation for escitalopram oxalate and clonazepam were established. The stress test solutions were assayed against the qualified working standards of escitalopram oxalate and clonazepam, which indicated that the developed LC method was stability-indicating. Validation of the developed LC method was conducted as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of escitalopram oxalate and clonazepam.

  11. Spectroscopic study of the inhibition of calcium oxalate calculi by Larrea tridentata

    Science.gov (United States)

    Pinales, Luis Alonso

    The causes of urolithiasis include such influences as diet, metabolic disorders, and genetic factors which have been documented as sources that aggravate urinary calculi depositions and aggregations, and, implicitly, as causes of urolithiasis. This study endeavors to detail the scientific mechanisms involved in calcium oxalate calculi formation, and, more importantly, their inhibition under growth conditions imposed by the traditional medicinal approach using the herbal extract, Larrea tridentata. The calculi were synthesized without and with Larrea tridentata infusion by employing the single diffusion gel technique. A visible decrease in calcium oxalate crystal growth with increasing amounts of Larrea tridentata herbal infusion was observed in photomicrographs, as well as a color change from white-transparent for pure crystals to light orange-brown for crystals with inhibitor. Analysis of the samples, which includes Raman, infrared absorption, scanning electron microscopy (SEM), and X-ray powder diffraction (XRD) techniques, demonstrate an overall transition in morphology of the crystals from monohydrate without herbal extract to dihydrate with inhibitor. Furthermore, the resulting data from Raman and infrared absorption support the possibilities of the influences, in this complex process, of NDGA and its derivative compounds from Larrea tridentata, and of the bonding of the magnesium of the inhibitor with the oxalate ion on the surface of the calculi crystals. This assumption corroborates well with the micrographs obtained under higher magnification, which show that the separated small crystallites consist of darker brownish cores, which we attribute to the dominance of growth inhibition by NDGA, surrounded by light transparent thin shells, which possibly correspond to passivation of the crystals by magnesium oxalate. The SEM results reveal the transformation from the dominant monoclinic structure of the calcium oxalate crystals grown alone to the tetragonal

  12. Two novel metal–organic coordination polymers based on diphosphonate and oxalate: Synthesis, structures and properties

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Qing-Jun; Zheng, Yue-Qing, E-mail: yqzhengmc@163.com; Zhou, Lin-Xia; Zhu, Hong-Lin

    2015-07-15

    Two 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonato and oxalic acid bridged coordination polymers (H{sub 2}en)[Co{sub 3}(H{sub 2}zdn){sub 2}(ox)(H{sub 2}O){sub 2}] (1) and Cd{sub 2}(H{sub 2}zdn)(ox){sub 0.5}(H{sub 2}O) (2) (2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid=H{sub 5}zdn; oxalic acid=H{sub 2}ox) were synthesized under hydrothermal conditions and characterized by the infrared (IR), thermogravimetric analyses (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Compound 1 is bridged by phosphonate anions to 1D chain, and further linked by oxalate anions to 2D layer. Compound 2 is bridged by O–P–O units of H{sub 5}zdn to the layer, and then pillared by oxalate anions to generate 3D frameworks. Compound 1 shows anti-ferromagnetic behaviors analyzed with the temperature-dependent zero-field ac magnetic susceptibilities, while compound 2 exhibits an influence on the luminescent property. - Graphical abstract: Linked by oxalate, two zoledronate-based metal–organic frameworks are synthesized, which exhibits the different frameworks. Magnetism and luminescent properties have been studied. The weak antiferromagnetic coupling is conducted in 1. - Highlights: • Compound 1 and 2 are first linked by oxalate anion based on zoledronic acid. • Compound 1 generates a classic “dia Diamond” (6{sup 6}) topology. • Compound 2 exhibits a (4{sup 4}·6{sup 2})(4{sup 4}·6{sup 6}) topology. • Magnetism and luminescent properties of 1 and 2 have been studied, respectively.

  13. Citric and Oxalic Acids Effect on Pb and Zn Uptake by Maize and Winter Wheat

    Institute of Scientific and Technical Information of China (English)

    Wang Xinmin; Hou Yanlin; Jie Xiaolei

    2004-01-01

    A pot experiment was conducted to investigate the influence of citric and oxalic acids effect on Pb and Zn uptake by corn and winter wheat.The experiment was employed with citric acid (CA)applied at 3 rates (0, 1.5 and 3.0 mmol kg-1 soil),oxalic acid (OA) at 3 rates (0, 1.5 and 3.0mmol kg-1soil) and citric acid combined with oxalic acid (1.5mmol citric acid combined with 1.5 mmol oxalic acid kg-1). Two types of soil were chose in the experiment.One was collected from the agricultural soil near a battery-recycling factory in Anhui province, China (site A) and the other was collected from a Pb-Zn mine residues in Hunan province, China (site B). The results showed that soil pH varied with the different treatment of citric and oxalic acids. However, there were no differences in all the treatments. 3.0mmol CA kg-1 soil addition significantly increased the concentrations of the CaCl2-extractable Pb and Zn and other treatments have no significantly increased.The highest shoot concentrations of Pb and Zn in both species occurred in application of 3.0 mmol CA/kg-1 soil and shoot concentrations of Pb and Zn in both species were significantly higher than the controls in this treatment. Shoot yields declined with application of citric and oxalic acids, indicating that the plants were sensitive to the toxicity of the metals or the amendments. The highest Pb uptake values by maize and wheat were112.3 and 77.2 μg pot-1in soil of site A, and occurred with the control and 3.0 mmol CA/kg-1 soil respectively.

  14. ANALYSIS OF MACRONUTRIENCONTENT, GLYCEMIC INDEX AND CALCIUM OXALATE ELIMINATION IN Amorphophallus campanulatus (Roxb.

    Directory of Open Access Journals (Sweden)

    Endang Lukitaningsih

    2013-10-01

    Full Text Available Recently, the research to find alternative sources of carbohydrates as a replacement for rice has been developed. Walur is one of the carbohydrate sources that can be explored because it can be grown in any area with out special treatment. However, walur has limitation for direct consumption, because it contains calcium oxalate. The purposes of this study were to determine the chemical character (macronutrient content, calculate glycemic index and get the proper washing techniques to elimin ate calcium oxalate of walur. Macro nutrients content studied in this research include carbohydrates, fats, protein, star chand crude fiber. Analysis of macronutrients has been chemically done, while the glycemic index was measured by in vivo using glucose as a standard. Elimination of calcium oxalate was conducted by washing the fresh walur tubers using a solution of0.01NHCl-NaOH, 5% NaCl, and solution of lemon-lime. The content of oxalate before and after washing was analyzed by permanganometry method. The results showed that walur containing 4.34 ±0.07% of reducingsugar,3.24 ± 0.06 % of not-reducing sugar, 11.27±0.40 % of crude fiber,0.03±1.05 % of starchand0.57±0.01 % of protein. Qualitative analysis of fatty acids showed that hexade canoicacid, octade cadienoicacid, and the acide icosatetranoic were detected in high concentrations. The glycemic index valueof walur was relative lylow, about of 16.9. In addition, washing technique using a solution of lemon-lime was the most excellent technique and can reduce the oxalate content up to61.82%.Fromthis research, it can be concluded that walur can be used as food substitute esrice after washing treatment using lemon-lime solution to remove the calcium oxalate content.

  15. Photodegradation of orange I in the heterogeneous iron oxide-oxalate complex system under UVA irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Jing [Faculty of Agriculture, Guangxi University, Nanning 630005 (China); Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China); Liu Chengshuai [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Fangbai [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China)]. E-mail: cefbli@soil.gd.cn; Li Xiaomin [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhou Shungui [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China); Liu Tongxu [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Gu Minghua [Faculty of Agriculture, Guangxi University, Nanning 630005 (China); Wu Qitang [College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642 (China)

    2006-09-21

    To understand the photodegradation of azo dyes in natural aquatic environment, a novel photo-Fenton-like system, the heterogeneous iron oxide-oxalate complex system was set up with the existence of iron oxides and oxalate. Five iron oxides, including {gamma}-FeOOH, IO-250, IO-320, IO-420 and IO-520, were prepared and their adsorption capacity was investigated in the dark. The results showed that the saturated adsorption amount ({gamma}{sub max}) was ranked the order of IO-250>IO-320>{gamma}-FeOOH>IO-420>IO-520 and the adsorption equilibrium constant (K{sub a}) followed the order of IO-250>IO-520>{gamma}-FeOOH>IO-420>IO-320. The effect of initial pH value, the initial concentrations of oxalate and orange I on the photodegradation of orange I were also investigated in different iron oxide-oxalate systems. The results showed that the photodegradation of orange I under UVA irradiation could be enhanced greatly in the presence of oxalate. And the optimal oxalate concentrations (C{sub ox}{sup 0}) for {gamma}-FeOOH, IO-250, IO-320, IO-420 and IO-520 were 1.8, 1.6, 3.5, 3.0 and 0.8mM, respectively. The photodegradation of orange I in the presence of optimal C{sub ox}{sup 0} was ranked as the order of {gamma}-FeOOH>IO-250>IO-320>IO-420>IO-520. The optimal range of initial pH was at about 3-4. The first-order kinetic constant for the degradation of orange I decreased with the increase in the initial concentration of orange I. Furthermore, the variation of pH, the concentrations of Fe{sup 3+} and Fe{sup 2+} during the photoreaction were also strongly dependent on the C{sub ox}{sup 0} and iron oxides.

  16. Photodegradation of orange I in the heterogeneous iron oxide-oxalate complex system under UVA irradiation.

    Science.gov (United States)

    Lei, Jing; Liu, Chengshuai; Li, Fangbai; Li, Xiaomin; Zhou, Shungui; Liu, Tongxu; Gu, Minghua; Wu, Qitang

    2006-09-21

    To understand the photodegradation of azo dyes in natural aquatic environment, a novel photo-Fenton-like system, the heterogeneous iron oxide-oxalate complex system was set up with the existence of iron oxides and oxalate. Five iron oxides, including gamma-FeOOH, IO-250, IO-320, IO-420 and IO-520, were prepared and their adsorption capacity was investigated in the dark. The results showed that the saturated adsorption amount (gamma(max)) was ranked the order of IO-250 > IO-320 > gamma-FeOOH > IO-420 > IO-520 and the adsorption equilibrium constant (Ka) followed the order of IO-250 > IO-520 > gamma-FeOOH > IO-420 > IO-320. The effect of initial pH value, the initial concentrations of oxalate and orange I on the photodegradation of orange I were also investigated in different iron oxide-oxalate systems. The results showed that the photodegradation of orange I under UVA irradiation could be enhanced greatly in the presence of oxalate. And the optimal oxalate concentrations (C(ox)0) for gamma-FeOOH, IO-250, IO-320, IO-420 and IO-520 were 1.8, 1.6, 3.5, 3.0 and 0.8 mM, respectively. The photodegradation of orange I in the presence of optimal C(ox)0 was ranked as the order of gamma-FeOOH > IO-250 > IO-320 > IO-420 > IO-520. The optimal range of initial pH was at about 3-4. The first-order kinetic constant for the degradation of orange I decreased with the increase in the initial concentration of orange I. Furthermore, the variation of pH, the concentrations of Fe3+ and Fe2+ during the photoreaction were also strongly dependent on the C(ox)0 and iron oxides.

  17. Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the beta-lactam producer Penicillium chrysogenum

    NARCIS (Netherlands)

    Gombert, A. K.; Veiga, T.; Puig-Martinez, M.; Lamboo, F.; Nijland, J. G.; Driessen, A. J. M.; Pronk, J. T.; Daran, J. M.

    2011-01-01

    Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of g-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate compl

  18. The roles of xylan and lignin in oxalic acid pretreated corncob during separate enzymatic hydrolysis and ethanol fermentation

    Science.gov (United States)

    Jae-Won Lee; Rita C.L.B. Rodrigues; Hyun Joo Kim; In-Gyu Choi; Thomas W. Jeffries

    2010-01-01

    High yields of hemicellulosic and cellulosic sugars are critical in obtaining economical conversion of agricultural residues to ethanol. To optimize pretreatment conditions, we evaluated oxalic acid loading rates, treatment temperatures and times in a 23 full factorial design. Response-surface analysis revealed an optimal oxalic acid pretreatment...

  19. MitoTEMPO Prevents Oxalate Induced Injury in NRK-52E Cells via Inhibiting Mitochondrial Dysfunction and Modulating Oxidative Stress

    Science.gov (United States)

    Yu, Xiao; Liu, Jihong

    2017-01-01

    As one of the major risks for urolithiasis, hyperoxaluria can be caused by genetic defect or dietary intake. And high oxalate induced renal epithelial cells injury is related to oxidative stress and mitochondrial dysfunction. Here, we investigated whether MitoTEMPO, a mitochondria-targeted antioxidant, could protect against oxalate mediated injury in NRK-52E cells via inhibiting mitochondrial dysfunction and modulating oxidative stress. MitoSOX Red was used to determine mitochondrial ROS (mtROS) production. Mitochondrial membrane potential (Δψm) and quantification of ATP synthesis were measured to evaluate mitochondrial function. The protein expression of Nox4, Nox2, and p22 was also detected to explore the effect of oxalate and MitoTEMPO on NADPH oxidase. Our results revealed that pretreatment with MitoTEMPO significantly inhibited oxalate induced lactate dehydrogenase (LDH) and malondialdehyde (MDA) release and decreased oxalate induced mtROS generation. Further, MitoTEMPO pretreatment restored disruption of Δψm and decreased ATP synthesis mediated by oxalate. In addition, MitoTEMPO altered the protein expression of Nox4 and p22 and decreased the protein expression of IL-6 and osteopontin (OPN) induced by oxalate. We concluded that MitoTEMPO may be a new candidate to protect against oxalate induced kidney injury as well as urolithiasis.

  20. Leaf calcium oxalate crystal structure and its role in defense against a chewing insect in Medicago truncatula

    Science.gov (United States)

    Crystals of calcium oxalate are common in plants and widely distributed among many plant families. These hard and largely insoluble crystals take on many shapes and sizes depending on the tissue and species. In Medicago truncatula, calcium oxalate crystals are abundant in leaves and accumulate in sh...

  1. The crystal structure of paramagnetic copper(ii) oxalate (CuC2O4):

    DEFF Research Database (Denmark)

    Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel

    2014-01-01

    Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have the composi...

  2. Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the β-lactam producer Penicillium chrysogenum

    NARCIS (Netherlands)

    Daran, J.M.; Pronk, J.T.; Driessen, A.J.M.; Nijland, J.G.; Lamboo, F.; Puig-Martinez, M.; Veiga, T.; Gombert, A.K.

    2011-01-01

    Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of ß-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate compl

  3. Enzymatic Method for Rapid Determination of Oxalic Acid in Bleaching Filtrates from the Pulp and Paper Industry

    Institute of Scientific and Technical Information of China (English)

    HONG Feng; SJ(O)DE Anders; NILVEBRANT Nils-Olof; J(O)NSSON Leif J.

    2005-01-01

    Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry.Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method.Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching filtrates from the pulp and paper industry. The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.

  4. Thermodynamics for complex formation between palladium(ii) and oxalate.

    Science.gov (United States)

    Pilný, Radomír; Lubal, Přemysl; Elding, Lars I

    2014-08-28

    Complex formation between [Pd(H2O)4](2+) and oxalate (ox = C2O4(2-)) has been studied spectrophoto-metrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HClO4 ionic medium for the complex formation [Pd(H2O)4](2+) + H2ox ⇄ [Pd(H2O)2(ox)] + 2H3O(+) with equilibrium constant K1,H (in mol dm(-3)) are log10K1,H = 3.38 ± 0.08, ΔH = -33 ± 3 kJ mol(-1), and ΔS = -48 ± 11 J K(-1) mol(-1), as determined from spectrophotometric equilibrium titrations at 15.0, 20.0, 25.0 and 31.0 °C. Thermodynamic overall stability constants β (in (mol dm(-3))(-n), n = 1,2) for [Pd(H2O)2(ox)] and [Pd(ox)2](2-) at zero ionic strength and 298.2 K, defined as the equilibrium constants for the reaction Pd(2+) + nox(2-) ⇄ [Pd(ox)n](2-2n) (water molecules omitted) are log10β = 9.04 ± 0.06 and log10β = 13.1 ± 0.3, respectively, calculated by use of Specific Ion Interaction Theory from spectrophotometric titrations with initial hydrogen ion concentrations of 1.00, 0.100 and 0.0100 mol dm(-3) and ionic strengths of 1.00, 2.00 or 3.00 mol dm(-3). The values derived together with literature data give estimated overall stability constants for Pd(ii) compounds such as [Pd(en)(ox)] and cis-[Pd(NH3)2Cl2], some of them analogs to Pt(ii) complexes used in cancer treatment. The palladium oxalato complexes are significantly more stable than palladium(ii) complexes with monodentate O-bonding ligands. A comparison between several different palladium complexes shows that different parameters contribute to the stability variations observed. These are discussed together with the so-called chelate effect.

  5. Field Assessment of Yeast- and Oxalic Acid-generated Carbon Dioxide for Mosquito Surveillance

    Science.gov (United States)

    2014-12-01

    generated by electro-stripping oxalic acid was produced by a Moustiq- AirTM CO2 generator (Med-e-Cell, San Diego, CA) powered with a lithium iron (Li...Moustiq- AirTM oxalic acid generator in the laboratory, and the positioning of (C) the 2 yeast tanks and (D) the Moustiq-Air when paired with a...Average flow rate (ml/min) 6 S0 generated by a single yeast-fermentation bottle (35 g yeast, 250 g sugar, 2.5 liters water), and by the Moustiq- AirTM

  6. Solid phase precipitates in (Zr,Th)-OH-(oxalate, malonate) ternary aqueous system

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, T.; Sasaki, T.; Takagi, I.; Moriyama, H. [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2009-07-01

    The solubility-limiting solid phases in the ternary aqueous systems of Zr(IV)/OH/oxalate, Zr(IV)/OH/malonate, Th(IV)/OH/oxalate and Th(IV)/OH/malonate were characterized by elemental analysis, X-ray diffraction, thermogravimetric analysis and differential thermal analysis. The ternary solid phase of M(IV)/OH/carboxylate was observed to form, even under acidic conditions, depending on the pH and the concentration of carboxylate ligand. In the presence of a large excess of carboxylic acid, however; the binary M(IV)-carboxylate solid phase formed. (orig.)

  7. Effect of Diluents on the Extraction of Oxalic Acid by Trialkylphosphine Oxide

    Institute of Scientific and Technical Information of China (English)

    李玉鑫; 王运东; 戴猷元

    2004-01-01

    Abstract In liquid-liquid solvent extraction processes, diluents have a strong influence on the extraction mechanism and efficiency. In this study, benzene, cyclohexane, trichloromethane, carbon tetrachloride, methyl isobutyl ketone (MIBK), butyl acetate, and 1-octanol were used as diluents in the extraction of oxalic acid by trialkylphosphine oxide (TRPO). The effects of extractant concentration, initial concentration of oxalic acid and diluent type on the extraction equilibrium partition coefficient are analyzed. The sequence of the extraction ability by different diluents is MIBK > butyl acetate > cyclohexane=benzene > carbon tetrachloride > 1-octanol > trichloromethane. Extraction mechanism was analyzed and extraction model parameters were evaluated.

  8. The influence of crystal morphology on the kinetics of growth of calcium oxalate monohydrate

    Science.gov (United States)

    Millan, A.; Sohnel, O.; Grases, F.

    1997-08-01

    The growth of several calcium oxalate monohydrate seeds in the presence and absence of additives (phytate, EDTA and citrate) has been followed by potentiometry measurements. Growth rates have been calculated from precipitate curves by a cubic spline method and represented in logarithmic plots versus supersaturation. Crystal growth kinetics were found to be dependent on crystal morphology, crystal perfection and degree of aggregation. Some seeds were dissolving in supersaturated solutions. Other seeds showed an initial growth phase of high-order kinetics. The effect of the additives was also different on each seed. Three alternative mechanisms for calcium oxalate crystal growth are proposed.

  9. Characterization of calcium oxalate biominerals in some (non-Cactaceae) succulent plant species.

    Science.gov (United States)

    Monje, Paula V; Baran, Enrique J

    2010-01-01

    The water-accumulating leaves of crassulacean acid metabolism plants belonging to five different families were investigated for the presence of biominerals by infrared spectroscopic and microscopic analyses. Spectroscopic results revealed that the mineral present in succulent species of Agavaceae, Aizoaceae, and Asphodelaceae was calcium oxalate monohydrate (whewellite, CaC2O4 x H2O). Crystals were predominantly found as raphides or solitary crystals of various morphologies. However, representative Crassulaceae members and a succulent species of Asteraceae did not show the presence of biominerals. Overall, these results suggest no correlation between calcium oxalate generation and crassulacean acid metabolism in succulent plants.

  10. Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

    Institute of Scientific and Technical Information of China (English)

    OUYANG; Jianming; DENG; Suiping; LI; Xiangping; TAN; Yanh

    2004-01-01

    [1]Ouyang, J. M., Yao, X. Q., Su, Z. X. et al., Simulation of calcium oxalate stone in Vitro, Science in China, Ser. B, 2003, 46(3):234-242.[2]Xu, S. H., Chen, J. Q., Zhou, H., Nepidemiological study of renal calculus in Shenshen region, Chin. J. Urol. (in Chinese), 1999,20(11): 655-657.[3]Bretherton, T., Rodgers, A., Crystallization of calcium oxalate in minimally diluted urine, J. Crystal Growth, 1998, 192: 448-455.[4]Grover, P. K., Ryall, R. L., Effect of seed crystals of uric acid and monosodium urate on the crystallization of CaOxa in undiluted human urine in vitro, Clin. Sci., 1997, 92: 205-213.[5]Laube, N., Mohr, B., Hesse, A., Laser-probe-based investigation of the evolution of particle size distributions of calcium oxalate particles formed in artificial urines, J. Crystal Growth, 2001, 233:367-374.[6]Tunik, L., Fueredi-Milhofer, H., Garti, N., Adsorption of sodium diisooctyl sulfosuccinate onto calcium oxalate crystals, Langmuir,1998, 14: 3351-3355.[7]Cody, A. M., Cody, R. D., Calcium oxalate trihydrate phase control by structurally-specific carboxylic acids, J. Cryst. Growth,1994, 135: 234-245.[8]Ouyang, J. M., Duan, L., Tieke, B., Effects of carboxylic acids on the crystal growth of calcium oxalate nanoparticles in lecithin-water liposome systems, Langmuir, 2003, 19: 8980-8985.[9]Guo, S., Ward, M. D., Wesson, J. A., Direct visualization of calcium oxalate monohydrate crystallization and dissolution with atomic force microscopy and the role of polymeric additives,Langmuir, 2002, 18:4284-4291.[10]Yasui, T., Sato, M., Fujita, K., Effects of citrate on renal stone formation and osteopontin expression in a rat urolithiasis model,Urol. Res., 2001,29: 50-56.[11]Ouyang, J. M., Deng, S. P., Controlled and uncontrolled crystallization of calcium oxalate monohydrate in the presence of citric acid, Dalton Transactions, 2003, (14): 2846-2851.[12]Khan, S. R., Whalen, P. O., Glenton, P. A., Heterogeneous nucleation of

  11. Diuron degradation in irradiated, heterogeneous iron/oxalate systems: the rate-determining step.

    Science.gov (United States)

    Mazellier, P; Sulzberger, B

    2001-08-15

    The purpose of this study was to examine the various factors that control the kinetics of diuron degradation in irradiated, aerated suspensions containing goethite (alpha-FeOOH) and oxalate, in the following denoted as heterogeneous photo-Fenton systems. In these systems, attack by hydroxyl radicals (HO.) was the only pathway of diuron degradation. Studies were conducted in systems containing initially 80 or 200 mg L(-1) goethite (corresponding to 0.9 or 2.25 mM total iron) and 20, 50, 75, 100, 200, and 400 microM oxalate at 3 heterogeneous photo-Fenton systems.

  12. A kinetic and ESR investigation of iron(II) oxalate oxidation by hydrogen peroxide and dioxygen as a source of hydroxyl radicals

    DEFF Research Database (Denmark)

    Park, J S; Wood, P M; Davies, Michael Jonathan

    1997-01-01

    The reaction of Fe(II) oxalate with hydrogen peroxide and dioxygen was studied for oxalate concentrations up to 20 mM and pH 2-5, under which conditions mono- and bis-oxalate complexes (Fe[II](ox) and Fe[II](ox)2[2-]) and uncomplexed Fe2+ must be considered. The reaction of Fe(II) oxalate with hy...

  13. Viscosities of oxalic acid and its salts in water and binary aqueous mixtures of tetrahydrofuran at different temperatures

    Indian Academy of Sciences (India)

    M L Parmar; M K Guleria

    2005-07-01

    Relative viscosities for the solutions of oxalic acid and its salts, viz. ammonium oxalate, sodium oxalate and potassium oxalate, at different concentrations have been determined in water and in binary aqueous mixtures of tetrahydrofuran (THF) [5, 10, 15 and 20% by weight of THF] at 298.15 K, and in water and in 5% (w/w) THF + water at five different temperatures. The data have been evaluated using the Jones-Dole equation and the obtained parameters have been interpreted in terms of solute-solute and solute-solvent interactions. The activation parameters of viscous flow have been obtained which depicts the mechanism of viscous flow. The oxalic acid and its salts behave as structure breakers in water and in binary aqueous mixtures of THF.

  14. Oxalate-metabolising genes of the white-rot fungus Dichomitus squalens are differentially induced on wood and at high proton concentration

    NARCIS (Netherlands)

    Mäkelä, Miia R; Sietiö, Outi-Maaria; de Vries, Ronald P; Timonen, Sari; Hildén, Kristiina; van den Brink, J.

    2014-01-01

    Oxalic acid is a prevalent fungal metabolite with versatile roles in growth and nutrition, including degradation of plant biomass. However, the toxicity of oxalic acid makes regulation of its intra- and extracellular concentration crucial. To increase the knowledge of fungal oxalate metabolism, a tr

  15. Diminution of oxalate induced renal tubular epithelial cell injury and inhibition of calcium oxalate crystallization in vitro by aqueous extract of Tribulus terrestris

    Directory of Open Access Journals (Sweden)

    A. Aggarwal

    2010-08-01

    Full Text Available PURPOSE: Recurrence and persistent side effects of present day treatment for urolithiasis restrict their use, so an alternate solution, using phytotherapy is being sought. The present study attempted to evaluate the antilithiatic properties of Tribulus terrestris commonly called as “gokhru” which is often used in ayurveda to treat various urinary diseases including urolithiasis. MATERIALS AND METHODS: The activity of Tribulus terrestris was investigated on nucleation and the growth of the calcium oxalate (CaOx crystals as well as on oxalate induced cell injury of NRK 52E renal epithelial cells. RESULTS: Tribulus terrestris extract exhibited a concentration dependent inhibition of nucleation and the growth of CaOx crystals. When NRK-52E cells were injured by exposure to oxalate for 72 h, Tribulus terrestris extract prevented the injury in a dose-dependent manner. On treatment with the different concentrations of the plant, the cell viability increased and lactate dehydrogenase release decreased in a concentration dependent manner. CONCLUSION: The current data suggests that Tribulus terrestris extract not only has a potential to inhibit nucleation and the growth of the CaOx crystals but also has a cytoprotective role. Our results indicate that it could be a potential candidate for phytotherapy against urolithiasis.

  16. Reduction of oxalate-induced renal tubular epithelial (NRK-52E cell injury and inhibition of calcium oxalate crystallisation in vitro by aqueous extract of Achyranthes aspera

    Directory of Open Access Journals (Sweden)

    Aggarwal Anshu

    2010-01-01

    Full Text Available Despite considerable progress in medical therapy, there is no satisfactory drug to treat kidney stones. Therefore, this study is aimed to look for an alternative treatment by using Achyranthes aspera. Here, the inhibitory potency of A. aspera was investigated on nucleation and the growth of the calcium oxalate (CaOx crystals as well as on oxalate-induced cell injury of NRK 52E renal epithelial cells in vitro. Data are expressed as mean values of three independent experiments (each in triplicate and analysed by the analysis of variance (P < 0.05 to estimate the differences between values of extracts tested. A. aspera extract exhibited a concentration-dependent inhibition of the growth of CaOx crystals but a similar pattern of inhibition was not observed with increase in the plant extract concentration for the nucleation assay. When NRK 52E cells were injured by exposure to oxalate for 72 hours, A. aspera extract prevented the injury in a dose-dependent manner. On treatment with the different concentrations of the plant, the cell viability increased and the lactate dehydrogenase (LDH release decreased in a concentration-dependent manner. These studies indicate that A. aspera extract besides having a cytoprotective role also has a potential to inhibit both nucleation and the growth of the CaOx crystals and can prove to be a potent candidate for phytotherapy against urolithiasis.

  17. Synthesis, characterization and thermal studies of Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate: the single crystal structure of [(C(6)H(5))(CH(3))NCS(2)](4)Hg(2).

    Science.gov (United States)

    Onwudiwe, Damian C; Ajibade, Peter A

    2011-01-01

    Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.

  18. A model of relationship between climate and soil factors related to oxalate content in porang (Amorphophallus muelleri Blume corm

    Directory of Open Access Journals (Sweden)

    SERAFINAH INDRIYANI

    2011-01-01

    Full Text Available Indriyani S, Arisoesilaningsih E, Wardiyati T, Purnobasuki H (2011 A model of relationship between climate and soil factors related to oxalate content in porang (Amorphophallus muelleri Blume corm. Biodiversitas 12: 45-51. The abiotic environment as well as the biotic environment, involved climate and soil affect directly or indirectly to plant growth as well as plant substance. The objective of the research was to obtain a model of relationship between climate and soil factors related to oxalate content in porang corm. Porang corms were collected from five locations of porang agroforestry in East Java. The locations were (i Klangon Village, Saradan Subdistrict, Madiun District; (ii Klino Villlage, Sekar Subdistrict, Bojonegoro District; (iii Bendoasri Village, Rejoso Subdistrict, Nganjuk District; (iv Sugihwaras Village, Nggluyu Subdistrict, Nganjuk District and (v Kalirejo Village, Kalipare Subdistrict, Malang District. Geography variable consist of altitude. Climate variables consist of percentage of radiation, temperature and rainfall. Soil variables consist of electrical conductivity, pH, soil specific gravity, soil organic matter, available of calcium, and cation exchange capacity (CEC. Vegetation variables consist of species of plant tree and percentage of coverage. Porang vegetative growth variables consist of plant height, number of bulbil, canopy diameter, and petiole diameter. Corm variables consist of corm diameter, corm weight, and corm specific gravity. Oxalate variables consist of total oxalate, soluble oxalate, insoluble oxalate, and density of calcium oxalate crystal. Oxalate contents were measured based on AOAC method. All of variables were collected from first to fourth growth period of porang. Data were analyzed by smartPLS (Partial Least Square software. The results showed that there were significantly direct effect between altitude and temperature, altitude and CEC of soil, temperature and CEC of soil, altitude and

  19. Human serum transferrin: Is there a link between autism, high oxalate and iron deficiency anemia?

    Science.gov (United States)

    Luck, Ashley N.; Bobst, Cedric E.; Kaltashov, Igor A.; Mason, Anne B.

    2013-01-01

    It has been previously suggested that high amounts of oxalate in plasma could play a role in autism by binding to the bilobal iron transport protein transferrin (hTF) thereby interfering with iron metabolism by inhibiting iron delivery to cells. By examining the effect of the substitution of oxalate for the physiologically utilized synergistic carbonate anion in each lobe of hTF we sought to provide a molecular basis for or against such a role. Our work clearly shows both qualitatively (6 M urea gels) and quantitatively (kinetic analysis by stop flow spectrofluorimetry) that the presence of oxalate in place of carbonate in each binding site of hTF does indeed greatly interfere with iron removal from each lobe (both in the absence and presence of the specific hTF receptor). However, we also clearly demonstrate that once the iron is bound within each lobe of hTF, neither anion can displace the other. Additionally, as verified by urea gels and electrospray mass spectrometry, formation of completely homogeneous hTF-anion complexes requires that all iron must first be removed and hTF then reloaded with iron in the presence of either carbonate or oxalate. Of significance, experiments described herein show that carbonate is the preferred binding partner, i.e., even if an equal amount of each anion is available during the iron loading process the hTF-carbonate complex is formed. PMID:24152109

  20. Human serum transferrin: is there a link among autism, high oxalate levels, and iron deficiency anemia?

    Science.gov (United States)

    Luck, Ashley N; Bobst, Cedric E; Kaltashov, Igor A; Mason, Anne B

    2013-11-19

    It has been previously suggested that large amounts of oxalate in plasma could play a role in autism by binding to the bilobal iron transport protein transferrin (hTF), thereby interfering with iron metabolism by inhibiting the delivery of iron to cells. By examining the effect of the substitution of oxalate for the physiologically utilized synergistic carbonate anion in each lobe of hTF, we sought to provide a molecular basis for or against such a role. Our work clearly shows both qualitatively (6 M urea gels) and quantitatively (kinetic analysis by stopped-flow spectrofluorimetry) that the presence of oxalate in place of carbonate in each binding site of hTF does indeed greatly interfere with the removal of iron from each lobe (in the absence and presence of the specific hTF receptor). However, we also clearly demonstrate that once the iron is bound within each lobe of hTF, neither anion can displace the other. Additionally, as verified by urea gels and electrospray mass spectrometry, formation of completely homogeneous hTF-anion complexes requires that all iron must first be removed and hTF then reloaded with iron in the presence of either carbonate or oxalate. Significantly, experiments described here show that carbonate is the preferred binding partner; i.e., even if an equal amount of each anion is available during the iron loading process, the hTF-carbonate complex is formed.

  1. The role of nanoparticulate agglomerates in TiO2 photocatalysis: degradation of oxalic acid

    Science.gov (United States)

    Ivanova, Irina; Mendive, Cecilia B.; Bahnemann, Detlef

    2016-07-01

    The simultaneous bimodal study of the photocatalytic oxalic acid degradation by aqueous TiO2 suspensions revealed that particular systems possess the capacity to protect a certain amount of oxalic acid from oxidation, thus hindering, to some extent, the photocatalytic reaction. While measurements of the oxalic acid concentration in the bulk liquid phase indicated full photocatalytic degradation; in situ pH-stat measurements allowed the quantification of the amount of oxalic acid remaining in the part of the nanoparticulate agglomerates where light could apparently not access. An explanation for this phenomenon takes into account the possibility of the formation of TiO2 agglomerates in which these molecules are hidden from the effect of the light, thus being protected from photocatalytic degradation. Studies of different TiO2 materials with different particle sizes allowed a deeper exploration of this phenomenon. In addition, because this property of encapsulating pollutant molecules by photocatalytic systems is found to be a reversible phenomenon, P25 appears to be more convenient and advantageous as compared to the use of large surface area photocatalysts.

  2. An ATP and oxalate generating variant tricarboxylic acid cycle counters aluminum toxicity in Pseudomonas fluorescens.

    Directory of Open Access Journals (Sweden)

    Ranji Singh

    Full Text Available Although the tricarboxylic acid (TCA cycle is essential in almost all aerobic organisms, its precise modulation and integration in global cellular metabolism is not fully understood. Here, we report on an alternative TCA cycle uniquely aimed at generating ATP and oxalate, two metabolites critical for the survival of Pseudomonas fluorescens. The upregulation of isocitrate lyase (ICL and acylating glyoxylate dehydrogenase (AGODH led to the enhanced synthesis of oxalate, a dicarboxylic acid involved in the immobilization of aluminum (Al. The increased activity of succinyl-CoA synthetase (SCS and oxalate CoA-transferase (OCT in the Al-stressed cells afforded an effective route to ATP synthesis from oxalyl-CoA via substrate level phosphorylation. This modified TCA cycle with diminished efficacy in NADH production and decreased CO(2-evolving capacity, orchestrates the synthesis of oxalate, NADPH, and ATP, ingredients pivotal to the survival of P. fluorescens in an Al environment. The channeling of succinyl-CoA towards ATP formation may be an important function of the TCA cycle during anaerobiosis, Fe starvation and O(2-limited conditions.

  3. Effect of oxalic acid pretreatment of wood chips on manufacturing medium-density fiberboard

    Science.gov (United States)

    Xianjun Li; Zhiyong Cai; Eric Horn; Jerrold E. Winandy

    2011-01-01

    The main objective of this study was to evaluate the effect of oxalic acid (OA) wood chips pretreatment prior to refining, which is done to reduce energy used during the refining process. Selected mechanical and physical performances of medium-density fiberboard (MDF) – internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA)...

  4. Oxalic acid catalyzed solvent-free one pot synthesis of coumarins

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.

  5. Synthesis of Diethyl Oxalate by a Coupling-Regeneration Reaction of Carbon Monoxide

    Institute of Scientific and Technical Information of China (English)

    Fandong Meng; Genhui Xu; Baowei Wang; Xinbin Ma

    2002-01-01

    This article describes a process for the synthesis of diethyl oxalate by a coupling reaction ofcarbon monoxide, catalyzed by palladium in the presence of ethyl nitrite. The kinetics and mechanism ofthe coupling and regeneration reaction are also discussed. This paper presents the results of a scale-uptest of the catalyst and the process based on an a priori computer simulation.

  6. Oxalic Acid Catalyzed Three Component One Pot Synthesis of 3,4-Dihydroquinazolin-4-ones

    Institute of Scientific and Technical Information of China (English)

    SANGSHETTI Jaiprakash-N.; KOKARE Nagnnath-D.; SHINDE Devanand-B.

    2008-01-01

    An efficient one-pot method for synthesis of an array of 3,4-dihydroquinazolin-4-ones from anthranilicacid, triethyl orthoformate, and anilines using oxalic acid as a catalyst was described. The present protocol offers im-provements for the synthesis of 3,4-dihydroquinazolin-4-ones with regard to short reaction time, high yields of products, and simplicity in operation.

  7. Urolithiasis in a herd of beef cattle associated with oxalate ingestion.

    Science.gov (United States)

    Waltner-Toews, D; Meadows, D H

    1980-02-01

    An unusually high incidence of urinary calculi in a group of feeder cattle is described. Necropsy findings in one affected animal suggested that oxalates in the feed, specifically in fescue (Festuca spp.) seed screenings, may have been the cause. Low dietary calcium and decreased water intake by the cattle appear to have been predisposing factors. Control measures are discussed.

  8. Urolithiasis in a Herd of Beef Cattle Associated with Oxalate Ingestion

    OpenAIRE

    Waltner-Toews, D; Meadows, D H

    1980-01-01

    An unusually high incidence of urinary calculi in a group of feeder cattle is described. Necropsy findings in one affected animal suggested that oxalates in the feed, specifically in fescue (Festuca spp.) seed screenings, may have been the cause. Low dietary calcium and decreased water intake by the cattle appear to have been predisposing factors. Control measures are discussed.

  9. Association of Vitamin D Receptor Gene Polymorphisms with Calcium Oxalate Calcul us Disease

    Institute of Scientific and Technical Information of China (English)

    王少刚; 刘继红; 胡少群; 叶章群

    2003-01-01

    To study the relationship between polymorphism of vitamin D receptor (VDR) allele with formation of calcium oxalate calculus and find the predisposing genes of calcium oxalate calculus, we screened out 150 patients who suffered from calcium oxalate calculus. 36 of them had idiopathic hypercalciuria according to analysis of calculus component and assay of urine calcium. The polymorphisms of VDR gene Taq1, Apa1 and Fok1 were detected using PCR-RFLP technique and the correlation were analyzed between the polymorphism and urinary calculus or between the polymorphism and hypercalciuria. The difference in each genotypic frequency of the allele of promoter Fok1 between calculus group and healthy group or between idiopathic hypercalciuria calculus group and health group was significant. The content of 24-h urine calcium of those who had genotype ff was obviously higher than that of those who have other genotypes in the same group. There was no significant difference in the polymorphism of gene Apa1 and Taq1 between each two groups. It is concluded that hypercalciuria and calcium oxalate calculus were related to the polymorphism of VDR gene's promoter Fok1 allele, but it had nothing to do with the polymorphism of gene Apa1 and Taq1. The genotype ff was a candidate heredity marker of calcium calculus disease.

  10. Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate.

    Science.gov (United States)

    Warren, L M; Mackenzie, A; Dance, D R; Young, K C

    2013-04-07

    Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

  11. Simultaneous saccharification and ethanol fermentation of oxalic acid pretreated corncob assessed with response surface methodology

    Science.gov (United States)

    Jae-Won Lee; Rita C.L.B. Rodrigues; Thomas W. Jeffries

    2009-01-01

    Response surface methodology was used to evaluate optimal time, temperature and oxalic acid concentration for simultaneous saccharification and fermentation (SSF) of corncob particles by Pichia stipitis CBS 6054. Fifteen different conditions for pretreatment were examined in a 23 full factorial design with six axial points. Temperatures ranged from 132 to 180º...

  12. A Case of Randall's Plugs Associated to Calcium Oxalate Dihydrate Calculi

    Directory of Open Access Journals (Sweden)

    Felix Grases

    2016-07-01

    Full Text Available A case of a patient who developed multiple calcium oxalate dihydrate calculi, some of them connected to intratubular calcifications (Randall's plugs, is presented. Randall's plugs were isolated and studied. The mechanism of Randall's plug development is also suggested.

  13. Reconstruct Environmental Change through Reading Oxalate Records from the Ice Core

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ CAS scientists have made progress in investigating the past atmospheric changes by retrieving oxalate records from an ice core of Tianshan glaciers. An analysis shows that the variation of the organic acid mirrors the history of the regional economic development as well as environment protection in the west China over the past 40 years.

  14. Evaluation Of Sludge Heel Dissolution Efficiency With Oxalic Acid Cleaning At Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Sudduth, Christie; Vitali, Jason; Keefer, Mark

    2014-01-08

    The chemical cleaning process baseline strategy at the Savannah River Site was revised to improve efficiency during future execution of the process based on lessons learned during previous bulk oxalic acid cleaning activities and to account for operational constraints imposed by safety basis requirements. These improvements were also intended to transcend the difficulties that arise from waste removal in higher rheological yield stress sludge tanks. Tank 12 implemented this improved strategy and the bulk oxalic acid cleaning efforts concluded in July 2013. The Tank 12 radiological removal results were similar to previous bulk oxalic acid cleaning campaigns despite the fact that Tank 12 contained higher rheological yield stress sludge that would make removal more difficult than the sludge treated in previous cleaning campaigns. No appreciable oxalate precipitation occurred during the cleaning process in Tank 12 compared to previous campaigns, which aided in the net volume reduction of 75-80%. Overall, the controls established for Tank 12 provide a template for an improved cleaning process.

  15. Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Sanchez, Bernadette A.; Tuttle, Bruce Andrew

    2009-06-01

    Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

  16. Degradation of reactive dyes by ozonation and oxalic acid-assimilating bacteria isolated from soil.

    Science.gov (United States)

    Kurosumi, Akihiro; Kaneko, Erika; Nakamura, Yoshitoshi

    2008-07-01

    Ozonation and treatment of wastewaters with oxalic acid-assimilating bacterium was attempted for the complete degradation of reactive dyes. Oxalic acid-assimilating bacterium, Pandoraea sp. strain EBR-01, was newly isolated from soil under bamboo grove and was identified to be a member of the genus Pandoraea by physicochemical and biochemical tests including 16S rDNA sequence analysis. The bacterium was grown optimally at pH 7 and temperature of 30 degrees C under the laboratory conditions. Reactive Red 120 (RR120), Reactive Green 19 (RG19), Reactive Black 5 (RB5) and Remazol Brilliant Blue R (RBBR) were used in degradation experiments. At the initial reactive dye concentrations of 500 mg/l and the ozonation time of 80 min, it was confirmed that 75-90 mg/l oxalic acid was generated from reactive dyes by ozonation. Microbial treatment using EBR-01 greatly decreased the amount of oxalic acid in the mixture after 48 h, but it was not removed completely. TOC/TOC(0) of reactive dye solutions was also decreased to 80-90% and 20-40% by ozonation and microbial treatment using EBR-01, respectively. The study confirmed that consecutive treatments by ozone and microorganisms are efficient methods to mineralize reactive dyes.

  17. Morphology and optical properties of aluminum oxide formed into oxalic electrolyte with addition surface active agents

    Science.gov (United States)

    Kazarkin, B.; Stsiapanau, A.; Zhilinski, V.; Chernik, A.; Bezborodov, V.; Kozak, G.; Danilovich, S.; Smirnov, A.

    2016-08-01

    The article discusses the results of investigations of porous films of alumina, formed into oxalic electrolyte with addition surface active agents, in particular, ordering structure, roughness of a surface, the optical transparency of the electrolyte concentration and surface active agents. Also discusses the features of the formation of porous films of temperature and IR radiation.

  18. Cell wall oxalate oxidase modifies the ferulate metabolism in cell walls of wheat shoots.

    Science.gov (United States)

    Wakabayashi, Kazuyuki; Soga, Kouichi; Hoson, Takayuki

    2011-11-01

    Oxalate oxidase (OXO) utilizes oxalate to generate hydrogen peroxide, and thereby acts as a source of hydrogen peroxide. The present study was carried out to investigate whether apoplastic OXO modifies the metabolism of cell wall-bound ferulates in wheat seedlings. Histochemical staining of OXO showed that cell walls were strongly stained, indicating the presence of OXO activity in shoot walls. When native cell walls prepared from shoots were incubated with oxalate or hydrogen peroxide, the levels of ester-linked diferulic acid (DFA) isomers were significantly increased. On the other hand, the level of ester-linked ferulic acid (FA) was substantially decreased. The decrease in FA level was accounted neither by the increases in DFA levels nor by the release of FA from cell walls during the incubation. After the extraction of ester-linked ferulates, considerable ultraviolet absorption remained in the hemicellulosic and cellulose fractions, which was increased by the treatment with oxalate or hydrogen peroxide. Therefore, a part of FA esters may form tight linkages within cell wall architecture. These results suggest that cell wall OXO is capable of modifying the metabolism of ester-linked ferulates in cell walls of wheat shoots by promoting the peroxidase action via supply of hydrogen peroxide.

  19. A study about some phosphate derivatives as inhibitors of calcium oxalate crystal growth

    Science.gov (United States)

    Grases, F.; March, P.

    1989-08-01

    The kinetic of crystal growth of calcium oxalate monohydrate seed crystals were investigated potentiometrically in the presence of several phosphate derivatives, D-fructose-1,6-diphosphate, pyrophosphate, methylene diphosphonate and phytate, and it was found that in some cases they strongly inhibited crystal growth. The inhibitory action of the different substances assayed was comparatively evaluated.

  20. Metal oxalate complexes as novel inorganic dopants: Studies on their effect on conducting polyaniline

    Indian Academy of Sciences (India)

    R Murugesan; E Subramanian

    2002-12-01

    Doped polyaniline materials with metal oxalate complexes of Cr, Fe, Mn, Co and Al were synthesized by in situ chemical oxidative polymerization of aniline using potassium perdisulphate as oxidant in aqueous sulphuric acid medium. These polymer materials were characterized by chemical analyses, spectral studies (UV-visible and IR), X-ray diffraction and thermal techniques and also by conductivity measurements by four-probe technique. The presence of complex anion in polyaniline material was confirmed by chemical and spectral analyses. The yield and conductivity of metal oxalate doped polyanilines were found to be high when compared to the simple sulphate ion doped polyaniline prepared under similar condition. UV-visible and IR spectral features not only confirmed the polyaniline doping by complex anions but also substantiated their facilitating effect on conductivity. The X-ray diffraction patterns indicated some crystalline nature in metal oxalate doped polyaniline and amorphous in polyaniline sulphate salt. The conductivity of the polymer samples strongly depended on the degree of crystallinity induced by complex counter anions as dopant. All the polymer materials, as evident from TGA curves, were observed to undergo three-step degradation of water loss, de-doping and decomposition of polymer. Further, the thermal stability of polyaniline was found to improve on doping with metal oxalate complex.

  1. Oxalic acid complexes: Promising draw solutes for forward osmosis (FO) in protein enrichment

    KAUST Repository

    Ge, Qingchun

    2015-01-01

    Highly soluble oxalic acid complexes (OACs) were synthesized through a one-pot reaction. The OACs exhibit excellent performance as draw solutes in FO processes with high water fluxes and negligible reverse solute fluxes. Efficient protein enrichment was achieved. The diluted OACs can be recycled via nanofiltration and are promising as draw solutes.

  2. In-cloud oxalate formation in the global troposphere: A 3-D modeling study

    NARCIS (Netherlands)

    Myriokefalitakis, S.; Tsigaridis, K.; Mihalopoulos, N.; Sciare, J.; Nenes, A.; Kawamura, K.; Segers, A.; Kanakidou, M.

    2011-01-01

    Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and

  3. Oxalic acid pretreatment of rice straw particles and loblolly pine chips : release of hemicellulosic carbohydrates

    Science.gov (United States)

    Xianjun Li; Zhiyong Cai; Eric Horn; Jerrold E. Winandy

    2011-01-01

    This study was conducted to evaluate the effect of oxalic acid (OA) pretreatment on carbohydrates released from rice straw particles and wood chips. The results showed that OA treatment accelerated carbohydrates extraction from rice straw particles and wood chips. OA pretreatment dramatically increased the amount of carbohydrates extracted, up to 24 times for wood...

  4. Molybdenum carbide as an efficient catalyst for low-temperature hydrogenation of dimethyl oxalate.

    Science.gov (United States)

    Liu, Yanting; Ding, Jian; Sun, Jiaqiang; Zhang, Juan; Bi, Jicheng; Liu, Kefeng; Kong, Fanhua; Xiao, Haicheng; Sun, Yanping; Chen, Jiangang

    2016-04-11

    Silica-supported molybdenum carbide (Mo2C/SiO2) is found to be a highly active, selective and stable catalyst for the hydrogenation of dimethyl oxalate to ethanol at low temperatures (473 K). Moreover, the formation of ethanol over the Mo2C catalyst performs via the novel intermediate methyl acetate instead of ethylene glycol forming over the Cu catalyst.

  5. In-cloud oxalate formation in the global troposphere: A 3-D modeling study

    NARCIS (Netherlands)

    Myriokefalitakis, S.; Tsigaridis, K.; Mihalopoulos, N.; Sciare, J.; Nenes, A.; Kawamura, K.; Segers, A.; Kanakidou, M.

    2011-01-01

    Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and drople

  6. Formation of ring calcium oxalate patterns induced by domains in DPPC Langmuir-Blodgett films

    Institute of Scientific and Technical Information of China (English)

    Yi Ming Liu; Sui Ping Deng; Hui Zheng; Jian Ming Ouyang

    2007-01-01

    The ring patterns of calcium oxalate crystals were induced by domains in Langmuir-Blodgett (LB) films of dipalmitoylpho-sphatidylcholine (DPPC). The result was explained by the defects at the ring boundaries of liquid condensed (LC) and liquid expanded (LE) phases of LB film. These boundaries could provide less free energy and much more nucleating sites for COM crystals.

  7. Kaleidoscopic Views in the Bone Marrow: Oxalate Crystals in a Patient Presenting with Bicytopenia

    Directory of Open Access Journals (Sweden)

    Yelda Dere

    2016-03-01

    Full Text Available Pancytopenia associated with BM infiltration of different deposits is a rare condition mostly associated with amyloidosis or the accumulation of iron. One of the rarest deposits in the BM is oxalate crystals due to hyperoxaluria [1,2,3]. Primary hyperoxaluria, a genetic disorder due to mutation in the alanine glyoxylate aminotransferase gene, located on chromosome 2q37.3 and resulting in the conversion of glyoxylate to oxalate, is characterized by increased production of oxalic acid because of the specific liver enzyme deficiency and generally presents with renal stones, renal or liver failure, and oxalosis [4]. Calcium oxalate may even be deposited into various tissues such as those of the retina, peripheral nerves, arterial media, and heart [4,5]. The medical history of nephrolithiasis at early ages, characteristic appearance of birefringent crystals forming rosettes in the BM, and the envelope-like forms in the BM aspirates seen in our case supported the diagnosis of primary hyperoxaluria, which is best confirmed by genetic studies and treated with liver transplantation because of the location of the abnormal enzymes in the hepatocytes.

  8. Influence of essential and non-essential amino acids on calcium oxalate crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Sargut, S.T.; Sayan, P.; Kiran, B. [Marmara University, Faculty of Engineering, Department of Chemical Engineering, 34722 Istanbul (Turkey)

    2010-01-15

    The investigation on the mechanism of nucleation and growth of crystals at organic-inorganic interfaces is crucial for understanding biological and physiological calcification processes such as the formation of urinary stones. The effects of five different amino acids on the crystallization of calcium oxalate have been investigated at pH 4.5 and 37 C in aqueous solutions in the batch type crystallizer. The products were characterized by Scanning Electron Microscopy (SEM), Fourier Transfer Infrared Spectroscopy (FT/IR) and X-Ray diffraction (XRD) analysis. Crystal size distribution (CSD) and filtration rate measurements were done. In order to determine the adsorption characteristics of amino acids on the calcium oxalate crystal surfaces, zeta potential measurements were also done and discussed. The results indicate that in the presence of all investigated amino acids, calcium oxalate monohydrate (COM) crystals were preferentially produced, but the crystal morphology varied with amino acid types and concentrations. Various crystal morphologies such as elongated hexagonal, coffin or platy habits were observed. In the presence of all investigated amino acids, the calcium oxalate crystallized in a monohydrate form. Electrostatic/ionic interaction, different adsorption properties and special functional effects of amino acids led to find different crystal morphology. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Alarm Photosynthesis: Calcium Oxalate Crystals as an Internal CO2 Source in Plants.

    Science.gov (United States)

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-08-01

    Calcium oxalate crystals are widespread among animals and plants. In land plants, crystals often reach high amounts, up to 80% of dry biomass. They are formed within specific cells, and their accumulation constitutes a normal activity rather than a pathological symptom, as occurs in animals. Despite their ubiquity, our knowledge on the formation and the possible role(s) of these crystals remains limited. We show that the mesophyll crystals of pigweed (Amaranthus hybridus) exhibit diurnal volume changes with a gradual decrease during daytime and a total recovery during the night. Moreover, stable carbon isotope composition indicated that crystals are of nonatmospheric origin. Stomatal closure (under drought conditions or exogenous application of abscisic acid) was accompanied by crystal decomposition and by increased activity of oxalate oxidase that converts oxalate into CO2 Similar results were also observed under drought stress in Dianthus chinensis, Pelargonium peltatum, and Portulacaria afra Moreover, in A. hybridus, despite closed stomata, the leaf metabolic profiles combined with chlorophyll fluorescence measurements indicated active photosynthetic metabolism. In combination, calcium oxalate crystals in leaves can act as a biochemical reservoir that collects nonatmospheric carbon, mainly during the night. During the day, crystal degradation provides subsidiary carbon for photosynthetic assimilation, especially under drought conditions. This new photosynthetic path, with the suggested name "alarm photosynthesis," seems to provide a number of adaptive advantages, such as water economy, limitation of carbon losses to the atmosphere, and a lower risk of photoinhibition, roles that justify its vast presence in plants.

  10. Growth and characterization of cerium lanthanum oxalate crystals grown in hydro-silica gel

    Energy Technology Data Exchange (ETDEWEB)

    John, M.V.; Ittyachen, M.A. [Mahatma Gandhi Univ., Kerala (India). School of Pure and Applied Physics

    2001-07-01

    Single crystals of mixed cerium lanthanum oxalate (CLO) are grown by gel method. Over the hydrosilica gel prepared by mixing oxalic acid and sodium meta silicate, a mixture of aqueous solutions of cerium nitrate and lanthanum nitrate are poured gently. Cerium and lanthanum ions diffuse into the gel and react with oxalic acid to give colorless, transparent cerium lanthanum oxalate crystals with in a few days. Different growth parameters give crystals of various dimensions. Infrared (IR) spectrum confirms the presence of water molecules and carboxylic acid. X-ray diffraction (XRD) pattern of these samples reveals the crystalline nature. Diffraction peaks are indexed. Unit cell parameters are determined. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) data support the presence of 9 H{sub 2}O molecules attached to the CLO crystal lattice which are lost around 200 C as revealed by the endotherm record. Exothermic peak around 350 C-425 C shows the release of CO and CO{sub 2}. Elemental analysis done by energy dispersive X-ray fluorescence analysis (EDXRF) for the mixed rare earth compound is almost in good agreement with experimental and theoretical values. (orig.)

  11. Alleviation of chilling injury in tomato fruit by exogenous application of oxalic acid.

    Science.gov (United States)

    Li, Peiyan; Yin, Fei; Song, Lijun; Zheng, Xiaolin

    2016-07-01

    The effects of oxalic acid on the development of chilling injury (CI), energy metabolism and lycopene metabolism in tomato fruit (Solanum lycopersicum L.) were investigated. Mature green tomatoes were dipped in 10mmoll(-1) oxalic acid (OA) solution for 10min at 25°C. Tomatoes were subsequently stored at 4±0.5°C for 20days before being transferred to 25°C for 12days. Oxalic acid treatment apparently alleviated CI development and membrane damage; maintained higher levels of ATP and ADP; increased activities of succinic dehydrogenase (SDH), Ca(2+)-adenosine triphosphatase (Ca(2+)-ATPase) and H(+)-adenosine triphosphatase (H(+)-ATPase); and elevated lycopene accumulation associated with the upregulation of PSY1 and ZDS expression in tomatoes during a period at room temperature following exposure to chilling stress. Thus, oxalic acid treatment benefited the control of CI and the maintenance of fruit quality in tomatoes stored for long periods (approximately 32days). Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. A new method for the analysis of soluble and insoluble oxalate in pulp and paper matrices

    CSIR Research Space (South Africa)

    Sithole, Bruce

    2013-11-01

    Full Text Available . 7. Löwendahl, L., Petersson, G. and Samuelson, O., 1976, Tappi 59(9): 118. 8. Elsander, A., Ek, M. and Gellerstedt, G., 2000, Tappi J., 83(2): 73. 9. Fiskari, J. and Gullichsen, J., Laboratory experiments on oxalic acid formation in hardwood...

  13. Synthesis of Y2O3 Nano-Powder from Yttrium Oxalate under Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Li Ling

    2005-01-01

    High purity Y2O3 nano-powders was synthesized directly from solution of industrial YCl3 by method of oxalate precipitation through super-micro-reactors made by complex non-ionic surfactant. The purity and diameter of Y2O3 particles were controlled by such processing parameters as concentration of YCl3 and oxalic acid and complex non-ionic surfactant etc. TEM photomicrographs show that Y2O3 particles are spherical in shape, with an average diameter of less than 30 nm. Test results certify that the purity and particle diameter as well as the dispersion of Y2O3 nano-powder depend on the concentrations of YCl3, oxalic acid and complex non-ionic surfactant. The optimum ranges of the concentrations for YCl3 and complex non-ionic surfactant when the diameter of Y2O3 particles is smaller than 100 nm are 0.43~1.4 mol·L-1 and 0.031~0.112 mol·L-1 respectively, while the mass fraction range of oxalic acid is 10%~18%. The purity of Y2O3 nano-powder tested by ICP-AES analysis is 99.99%.

  14. Raman and FTIR spectroscopy of natural oxalates: Implications for the evidence of life on Mars

    Institute of Scientific and Technical Information of China (English)

    R. L. Frost; YANG Jing; Zhe Ding

    2003-01-01

    Evidence for the existence of primitive life forms such as lichens andfungi can be based upon the formation of oxalates. Oxalates are most readily detected using Raman spectroscopy. A comparative study of a suite of natural oxalates including weddellite, whewellite, moolooite, humboldtine, glushinskite, natroxalate and oxammite has been undertaken using Raman spectroscopy. The minerals are characterised by the Raman position of the CO stretching vibration which is cation sensitive. The band is observed at 1468 cm-1 for weddellite, 1489 cm-1 for moolooite, 1471 cm-1 for glushinskite and 1456 cm-1 for natroxalate. Except for oxammite, the infrared and Raman spectra are mutually exclusive indicating theminerals are bidentate. Differences are also observed in the water OH stretching bands of the minerals. The significance of this work rests with the ability of Raman spectroscopy to identify oxalates which often occur as a film on a host rock. As such Raman spectroscopy has the potential to identify the existence or pre-existence of life forms on planets such as Mars.

  15. ROLE OF THE MICROFLORA IN DISTAL INTESTINAL TRACT BY MAINTAINING OXALATE HOMEOSTASIS

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    Osolodchenko T.P.

    2015-05-01

    Full Text Available Human intestinal microflora is part of the human body and performs numerous function. Considerable research interest is in the field of probiotics for the prevention of kidney stones, which is one of the most common urological diseases.Urolithiasis is one of the most common urological diseases. This is polyetiological disease congenital and acquired character with complex physical and chemical processes that occur not only in the urinary system, but also the whole body. None of the treatments does not guarantee full recovery of the patient and often leads to relapse. The open methods of removal stones yield news minimally invasive the technologys. Development of stone formation depends on the presence of many factors, metabolic disorders, chronic urinary tract infections, genetic disorders and more. Most have the following metabolic disorders as hypercalciuria, hiperurikuria, hipotsytraturia , hyperoxaluria and hipomahniuria. Among all types of urolithiasis kaltsiyoksalatnyy ranked first in the prevalence rate - about 75.0 - 85.0 % of cases. Dietary restriction by oxalates іs the unreliable method of preventing disease. Although there is evidence for the growth inhibition normobiocenosis representatives, which in turn enhances the absorption of salts of oxalic acid oxalate in the application of sodium , magnesium and cobalt in their intragastric administration. Recently published many papers on the impact on the level of oxalate intestinal microflora. The first publications appeared on the influence of gram-negative obligate anaerobes O. formigenes the concentration of oxalate in the urine. This anaerobic bacteria living in the colon, its prevalence - 46.0 % - 77.0 % of the adult population. O. formigenes reveals the symbiotic interaction with the human body by reducing absorption of oxalate in the intestinal cavity with subsequent decrease in their concentration in plasma and urine. O. formigenes has two key enzymes - oksalyl

  16. Effect of Lagenaria siceraria fruit powder on sodium oxalate induced urolithiasis in Wistar rats

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    Rahul V Takawale

    2012-01-01

    Full Text Available Background: In spite of advances in the present practice of medicine, the formation and growth of calculi continues to trouble mankind, as there is no satisfactory drug to treat kidney stones. In India, many indigenous drugs are in use for the treatment of urinary calculus disease. Objective: The present study was intended to determine anti-urolithiatic effect of Lagenaria siceraria fruit powder (LSFP against sodium oxalate (NaOx induced urolithiasis in rats. Materials and Methods: Animals were grouped as Vehicle Group (received vehicle gum acacia 2% w/v 1 mL/kg/p.o., NaOx Group(Sodium oxalate 70 mg/kg,i.p., LSFP Group (500 mg/kg, p.o. LSFP suspended in gum acacia 2% + Sodium oxalate 70 mg/kg, Cystone Group (500 mg/kg, p.o. Cystone suspended in gum acacia 2% + Sodium oxalate 70 mg/kg. Result: The increased severity of microscopic calcium oxalate (CaOx crystals deposition along with increased concentration in the kidney was seen after 7 days of NaOx (70 mg/kg, i.p. pre-treatment. LSFP (500 mg/kg, p.o. and standard marketed formulation Cystone (500 mg/kg, p.o. caused a significant reversal of NaOx-induced changes in ion excretion and urinary CaOx concentration in 7 days treatment. Conclusion: From the results, it was concluded that LSFP showed beneficial effect against urolithiasis by decreasing CaOx excretion and preventing crystal deposition in the kidney tubules.

  17. Hyperoxaluria leads to dysbiosis and drives selective enrichment of oxalate metabolizing bacterial species in recurrent kidney stone endures

    Science.gov (United States)

    Suryavanshi, Mangesh V.; Bhute, Shrikant S.; Jadhav, Swapnil D.; Bhatia, Manish S.; Gune, Rahul P.; Shouche, Yogesh S.

    2016-01-01

    Hyperoxaluria due to endogenously synthesized and exogenously ingested oxalates is a leading cause of recurrent oxalate stone formations. Even though, humans largely rely on gut microbiota for oxalate homeostasis, hyperoxaluria associated gut microbiota features remain largely unknown. Based on 16S rRNA gene amplicons, targeted metagenomic sequencing of formyl-CoA transferase (frc) gene and qPCR assay, we demonstrate a selective enrichment of Oxalate Metabolizing Bacterial Species (OMBS) in hyperoxaluria condition. Interestingly, higher than usual concentration of oxalate was found inhibitory to many gut microbes, including Oxalobacter formigenes, a well-characterized OMBS. In addition a concomitant enrichment of acid tolerant pathobionts in recurrent stone sufferers is observed. Further, specific enzymes participating in oxalate metabolism are found augmented in stone endures. Additionally, hyperoxaluria driven dysbiosis was found to be associated with oxalate content, stone episodes and colonization pattern of Oxalobacter formigenes. Thus, we rationalize the first in-depth surveillance of OMBS in the human gut and their association with hyperoxaluria. Our findings can be utilized in the treatment of hyperoxaluria associated recurrent stone episodes. PMID:27708409

  18. C-Phycocyanin Confers Protection against Oxalate-Mediated Oxidative Stress and Mitochondrial Dysfunctions in MDCK Cells

    Science.gov (United States)

    Farooq, Shukkur M.; Boppana, Nithin B.; Asokan, Devarajan; Sekaran, Shamala D.; Shankar, Esaki M.; Li, Chunying; Gopal, Kaliappan; Bakar, Sazaly A.; Karthik, Harve S.; Ebrahim, Abdul S.

    2014-01-01

    Oxalate toxicity is mediated through generation of reactive oxygen species (ROS) via a process that is partly dependent on mitochondrial dysfunction. Here, we investigated whether C-phycocyanin (CP) could protect against oxidative stress-mediated intracellular damage triggered by oxalate in MDCK cells. DCFDA, a fluorescence-based probe and hexanoyl-lysine adduct (HEL), an oxidative stress marker were used to investigate the effect of CP on oxalate-induced ROS production and membrane lipid peroxidation (LPO). The role of CP against oxalate-induced oxidative stress was studied by the evaluation of mitochondrial membrane potential by JC1 fluorescein staining, quantification of ATP synthesis and stress-induced MAP kinases (JNK/SAPK and ERK1/2). Our results revealed that oxalate-induced cells show markedly increased ROS levels and HEL protein expression that were significantly decreased following pre-treatment with CP. Further, JC1 staining showed that CP pre-treatment conferred significant protection from mitochondrial membrane permeability and increased ATP production in CP-treated cells than oxalate-alone-treated cells. In addition, CP treated cells significantly decreased the expression of phosphorylated JNK/SAPK and ERK1/2 as compared to oxalate-alone-treated cells. We concluded that CP could be used as a potential free radical-scavenging therapeutic strategy against oxidative stress-associated diseases including urolithiasis. PMID:24691130

  19. A Potentiometric, Spectrophotometric and Pitzer Ion-Interaction Study of Reaction Equilibria in the Aqueous H+-Al3+, H+-Oxalate and H+-Al3+-Oxalate Systems up to 5 mol*dm-3 NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Boily, Jean F.; Qafoku, Odeta; Felmy, Andrew R.

    2007-12-01

    Aluminium-oxalate complexation was determined in acidic media of aqueous NaCl solutions ranging from 0.1-5.0 mol•dm-3. Complexation in the H+-Al3+ and H+-Oxalate systems was also studied to provide a set of internally consistent thermodynamic data. The ionic strength dependent formation constants describing the stabilities of the Al3+, AlOH2+, Al3(OH)45+, Al13O4(OH)247+, H2L, HL-, L2-, AlL+, AlL2- and AlL33- species (where L is the oxalate ion) was also described using a Pitzer ion interaction model. The derived parameters can be used to predict chemical speciation in the H+-Al3+-Oxalate system in the 0.1-5.0 mol•dm-3 NaCl range.

  20. Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation

    Science.gov (United States)

    Gan, Qiong-Zhi; Sun, Xin-Yuan; Bhadja, Poonam; Yao, Xiu-Qiong; Ouyang, Jian-Ming

    2016-01-01

    Background Renal epithelial cell injury facilitates crystal adhesion to cell surface and serves as a key step in renal stone formation. However, the effects of cell injury on the adhesion of nano-calcium oxalate crystals and the nano-crystal-induced reinjury risk of injured cells remain unclear. Methods African green monkey renal epithelial (Vero) cells were injured with H2O2 to establish a cell injury model. Cell viability, superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, propidium iodide staining, hematoxylin–eosin staining, reactive oxygen species production, and mitochondrial membrane potential (Δψm) were determined to examine cell injury during adhesion. Changes in the surface structure of H2O2-injured cells were assessed through atomic force microscopy. The altered expression of hyaluronan during adhesion was examined through laser scanning confocal microscopy. The adhesion of nano-calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) crystals to Vero cells was observed through scanning electron microscopy. Nano-COM and COD binding was quantitatively determined through inductively coupled plasma emission spectrometry. Results The expression of hyaluronan on the cell surface was increased during wound healing because of Vero cell injury. The structure and function of the cell membrane were also altered by cell injury; thus, nano-crystal adhesion occurred. The ability of nano-COM to adhere to the injured Vero cells was higher than that of nano-COD crystals. The cell viability, SOD activity, and Δψm decreased when nano-crystals attached to the cell surface. By contrast, the MDA content, reactive oxygen species production, and cell death rate increased. Conclusion Cell injury contributes to crystal adhesion to Vero cell surface. The attached nano-COM and COD crystals can aggravate Vero cell injury. As a consequence, crystal adhesion and aggregation are enhanced. These findings provide further insights into kidney stone

  1. The influence of oxalate-promoted growth of saponite and talc crystals

    Science.gov (United States)

    Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D.; Sears, S. Kelly; Hesse, Reinhard; Vali, Hojatollah

    2013-01-01

    The intercalating growth of new silicate layers or metal hydroxide layers in the interlayer space of other clay minerals is known from various mixed-layer clay minerals such as illite-smectite (I-S), chlorite-vermiculite, and mica-vermiculite. In a recent study, the present authors proposed that smectite-group minerals can be synthesized from solution as new 2:1 silicate layers within the low-charge interlayers of rectorite. That study showed how oxalate catalyzes the crystallization of saponite from a silicate gel at low temperatures (60ºC) and ambient pressure. As an extension of this work the aim of the present study was to test the claim that new 2:1 silicate layers can be synthesized as new intercalating layers in the low-charge interlayers of rectorite and whether oxalate could promote such an intercalation synthesis. Two experiments were conducted at 60ºC and atmospheric pressure. First, disodium oxalate solution was added to a suspension of rectorite in order to investigate the effects that oxalate anions have on the structure of rectorite. In a second experiment, silicate gel of saponitic composition (calculated interlayer charge −0.33 eq/O10(OH)2) was mixed with a suspension of rectorite and incubated in disodium oxalate solution. The synthesis products were extracted after 3 months and analyzed by X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). The treatment of ultrathin sections with octadecylammonium (nC = 18) cations revealed the presence of 2:1 layer silicates with different interlayer charges that grew from the silicate gel. The oxalate-promoted nucleation of saponite and talc crystallites on the rectorite led to the alteration and ultimately to the destruction of the rectorite structure. The change was documented in HRTEM lattice-fringe images. The crystallization of new 2:1 layer silicates also occurred within the expandable interlayers of rectorite but not as new 2:1 silicate layers parallel to the previous 2

  2. Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation

    Directory of Open Access Journals (Sweden)

    Gan QZ

    2016-06-01

    Full Text Available Qiong-Zhi Gan,1,2 Xin-Yuan Sun,1,2 Poonam Bhadja,1,2 Xiu-Qiong Yao,1,2 Jian-Ming Ouyang1,2 1Department of Chemistry, Jinan University, Guangzhou, People’s Republic of China; 2Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, People’s Republic of China Background: Renal epithelial cell injury facilitates crystal adhesion to cell surface and serves as a key step in renal stone formation. However, the effects of cell injury on the adhesion of nano-calcium oxalate crystals and the nano-crystal-induced reinjury risk of injured cells remain unclear.Methods: African green monkey renal epithelial (Vero cells were injured with H2O2 to establish a cell injury model. Cell viability, superoxide dismutase (SOD activity, malonaldehyde (MDA content, propidium iodide staining, hematoxylin–eosin staining, reactive oxygen species production, and mitochondrial membrane potential (ΔΨm were determined to examine cell injury during adhesion. Changes in the surface structure of H2O2-injured cells were assessed through atomic force microscopy. The altered expression of hyaluronan during adhesion was examined through laser scanning confocal microscopy. The adhesion of nano-calcium oxalate monohydrate (COM and calcium oxalate dihydrate (COD crystals to Vero cells was observed through scanning electron microscopy. Nano-COM and COD binding was quantitatively determined through inductively coupled plasma emission spectrometry.Results: The expression of hyaluronan on the cell surface was increased during wound healing because of Vero cell injury. The structure and function of the cell membrane were also altered by cell injury; thus, nano-crystal adhesion occurred. The ability of nano-COM to adhere to the injured Vero cells was higher than that of nano-COD crystals. The cell viability, SOD activity, and ΔΨm decreased when nano-crystals attached to the cell surface. By contrast, the MDA content, reactive oxygen species production

  3. Surfactant-free nickel-silver core@shell nanoparticles in mesoporous SBA-15 for chemoselective hydrogenation of dimethyl oxalate.

    Science.gov (United States)

    Li, Molly Meng-Jung; Ye, Linmin; Zheng, Jianwei; Fang, Huihuang; Kroner, Anna; Yuan, Youzhu; Tsang, Shik Chi Edman

    2016-02-11

    Surfactant-free bimetallic Ni@Ag nanoparticles in mesoporous silica, SBA-15 prepared by simple wet co-impregnation catalyse hydrogenation of dimethyl oxalate to methyl glycolate or ethylene glycol in high yield.

  4. Comparison of oxalate contents and recovery from two green juices prepared using a masticating juicer or a high speed blender

    Directory of Open Access Journals (Sweden)

    Leo Vanhanen

    2015-06-01

    Conclusion: Green juices prepared using common vegetables can contain high levels of soluble oxalates, which will vary with the type and proportion of vegetables used and whether or not the pulp fraction was retained during processing.

  5. Partial specific volume of cellulose N-phenyl carbamate

    Science.gov (United States)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  6. Second virial coefficient of cellulose tris(N-phenyl carbamate)

    Science.gov (United States)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  7. Second virial coefficient of amylose tris(N-phenyl carbamate)

    Science.gov (United States)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  8. 4-Nitro-N-phenyl­benzene­sulfonamide

    Science.gov (United States)

    Chaithanya, U.; Foro, Sabine; Gowda, B. Thimme

    2012-01-01

    In the title compound, C12H10N2O4S, the dihedral angle between the aromatic rings is 36.19 (18)°. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into C(4) chains running along the a axis. PMID:23125671

  9. Indium tin oxide thin films elaborated by sol-gel routes: The effect of oxalic acid addition on optoelectronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Kesim, Mehmet Tumerkan; Durucan, Caner, E-mail: cdurucan@metu.edu.tr

    2013-10-31

    Single layer indium tin oxide (ITO) thin films were deposited on glass using modified sol-gel formulations. The coating sols were prepared using indium (InCl{sub 3}∙ 4H{sub 2}O) and tin salts (SnCl{sub 4}∙ 5H{sub 2}O). The stable sols were obtained using ethanol (C{sub 2}H{sub 5}OH) and acetylacetone (C{sub 5}H{sub 8}O{sub 2}) as solvents and by the addition of oxalic acid dihydrate (C{sub 2}H{sub 2}O{sub 4}∙ 2H{sub 2}O) in different amounts. The effect of oxalic acid content in the sol formulation and post-coating calcination treatment (in air at 300–600 °C) on electrical/optical properties of ITO films have been reported. It was shown that film formation efficiency, surface coverage and homogeneity were all enhanced with oxalic acid addition. Oxalic acid modification also leads to a significant improvement in electrical conductivity without affecting the film thickness (45 ± 3 nm). ITO films exhibiting high transparency (≈ 93%, visible region) with a sheet resistance as low as 3.8 ± 0.4 kΩ/sqr have been formed by employing coating sols with optimized oxalic acid amount. The mechanisms and factors affecting the functional performance of oxalic acid-modified films have been thoroughly discussed and related to the microstructural and chemical characteristic of the films achieved by oxalic acid addition. - Highlights: • A solution-based method for processing indium tin oxide (ITO) thin film is reported. • Oxalic acid (OAD) modification leads to a highly compacted film microstructure. • Bulk resistivity of a single layer OAD-modified ITO film was determined as 0.02 Ωcm. • Thin films with transparency values higher than 90% were produced.

  10. Coadsorption of Cd(II) and oxalate ions at the TiO2/electrolyte solution interface.

    Science.gov (United States)

    Janusz, W; Matysek, M

    2006-04-01

    The study of the adsorptions of cadmium and oxalate ions at the titania/electrolyte interface and the changes of the electrical double layer (edl) structure in this system are presented. The adsorption of cadmium or oxalate ions was calculated from an uptake of their concentration from the solution. The concentration of Cd(II) or oxalate ions in the solution was determined by radiotracer method. For labeling the solution 14C and 115Cd isotopes were used. Coadsorption of Cd(II) and oxalic ions was determined simultaneously. Besides, the main properties of the edl, i.e., surface charge density and zeta potential were determined by potentiometer titration and electrophoresis measurements, respectively. The adsorption of cadmium ions increases with pH increase and shifts with an increase of the initial concentration of Cd(II) ions towards higher pH values. The adsorption process causes an increase of negatively charged sites on anatase and a decrease of the zeta potential with an increase of initial concentration of these ions. The adsorption of oxalate anions at the titania/electrolyte interface proceeds through the exchange with hydroxyl groups. A decrease of pH produces an increase of adsorption of oxalate ions. The processes of anion adsorption lead to increase the number of the positively charged sites at the titania surface. However, specific adsorption of bidenate ligand as oxalate on one surface hydroxyl group may form inner sphere complexes on the metal oxide surface and may overcharge the compact part of the edl. The presence of oxalate ions in the system affects the adsorption of Cd(II) ions on TiO2, increasing the adsorption at low pH range and decreasing the adsorption at high pH range. Using adsorption as a function of pH data, some characteristic parameters of adsorption envelope were calculated.

  11. Oxalic acid as an assisting agent for the electrodialytic remediation of chromated copper arsenate treated timber waste

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra B.; Mateus, Eduardo P.; Ottosen, Lisbeth M.

    1999-01-01

    The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber.......The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber....

  12. Oxalic acid as an assisting agent for the electrodialytic remediation of chromated copper arsenate treated timber waste

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra B.; Mateus, Eduardo P.; Ottosen, Lisbeth M.

    1999-01-01

    The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber.......The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber....

  13. Renal intratubular crystals and hyaluronan staining occur in stone formers with bypass surgery but not with idiopathic calcium oxalate stones.

    Science.gov (United States)

    Evan, Andrew P; Coe, Fredric L; Gillen, Daniel; Lingeman, James E; Bledsoe, Sharon; Worcester, Elaine M

    2008-03-01

    Whether idiopathic calcium oxalate (CaOx) stone formers form inner medullary collecting duct (IMCD) crystal deposits bears on pathogenetic mechanisms of stone formation. In prior work, using light and transmission electron microscopy, we have found no IMCD crystal deposits. Here, we searched serial sections of papillary biopsies from a prior study of 15 idiopathic calcium oxalate stone formers, 4 intestinal bypass patients with CaOx stones, and 4 non-stone-forming subjects, and biopsies from an additional hitherto unreported 15 idiopathic calcium oxalate stone formers and 1 bypass patient using polarized light oil immersion optics, for deposits overlooked in our original study. We found no IMCD deposits in any of 1,500 serial sections from the 30 idiopathic calcium oxalate stone formers, nor in 87 additional sections from a frozen idiopathic calcium oxalate stone former biopsy sample processed without exposure to aqueous solutions. Among 4 of the 5 bypass patients but in none of the 30 idiopathic calcium oxalate stone formers or 4 normal stone formers, we found tiny birefringent thin crystalline overlays on scattered IMCD cell membranes. We also found IMCD lumen deposits in two bypass patients that contained mixed birefringent and nonbirefringent crystals, presumably CaOx and apatite. In the bypass patients, we observed focal apical IMCD cell hyaluronan staining, which was absent in idiopathic calcium oxalate stone formers. The absence of any IMCD deposits in 1,500 serial sections of biopsies from 30 idiopathic calcium oxalate stone formers allows us to place the upper limit on the probability of their occurrence at approximately 0.002 and place the lower limit of their size at the resolution of the optics (crystal lesion.

  14. Genome wide analysis of differentially expressed genes in HK-2 cells, a line of human kidney epithelial cells in response to oxalate.

    Directory of Open Access Journals (Sweden)

    Sweaty Koul

    Full Text Available Nephrolithiasis is a multi-factorial disease which, in the majority of cases, involves the renal deposition of calcium oxalate. Oxalate is a metabolic end product excreted primarily by the kidney. Previous studies have shown that elevated levels of oxalate are detrimental to the renal epithelial cells; however, oxalate renal epithelial cell interactions are not completely understood. In this study, we utilized an unbiased approach of gene expression profiling using Affymetrix HG_U133_plus2 gene chips to understand the global gene expression changes in human renal epithelial cells [HK-2] after exposure to oxalate. We analyzed the expression of 47,000 transcripts and variants, including 38,500 well characterized human genes, in the HK2 cells after 4 hours and 24 hours of oxalate exposure. Gene expression was compared among replicates as per the Affymetrix statistical program. Gene expression among various groups was compared using various analytical tools, and differentially expressed genes were classified according to the Gene Ontology Functional Category. The results from this study show that oxalate exposure induces significant expression changes in many genes. We show for the first time that oxalate exposure induces as well as shuts off genes differentially. We found 750 up-regulated and 2276 down-regulated genes which have not been reported before. Our results also show that renal cells exposed to oxalate results in the regulation of genes that are associated with specific molecular function, biological processes, and other cellular components. In addition we have identified a set of 20 genes that is differentially regulated by oxalate irrespective of duration of exposure and may be useful in monitoring oxalate nephrotoxicity. Taken together our studies profile global gene expression changes and provide a unique insight into oxalate renal cell interactions and oxalate nephrotoxicity.

  15. Reevaluation of the plant "gemstones": Calcium oxalate crystals sustain photosynthesis under drought conditions.

    Science.gov (United States)

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-09-01

    Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path "alarm photosynthesis." The so-far "enigmatic," but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants.

  16. Stannous oxalate as a novel catalyst for the synthesis of polytrimethylene terephthalate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibited higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate (PTT) via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260 ℃ after 1.5 h,while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polyester, polymerized at 260 ℃,60 Pa for 2 h, was 0.8950 dL/g and 15 mol/t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester.(C) 2007 Yun Cheng Cui. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  17. Construction and Characterization of Coated Wire Oxalate Ion Selective Electrode Based on Chitosan

    Directory of Open Access Journals (Sweden)

    Zuri Rismiarti

    2013-10-01

    Full Text Available PVC (polyvinyl chloride membrane based coated wire oxalate ion selective electrode has been developed by using chitosan. The results showed the optimum composition of the membrane was chitosan: aliquat 336: PVC: DBP = 4:1:33:62 (% weight. The electrode showed Nernstian response, Nernst factor 29.90 mV/decade of concentration, linier concentration range of 1x10-5 - 1x10-1 M, detection limit of 2.56 x10-6 M, response time of 30 second, and life time of 42 days. ISE’s performance worked well in pH range of 5-7 and temperature of 25-50 oC. Validation test showed no significant difference (t test with the SSA method so that the potentiometric method could be used as an alternative method for determining urinary oxalate.

  18. ELECTROCHEMICAL STUDIES ON THE CORROSION OF CARBON STEEL IN OXALIC ACID CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; John Mickalonis, J

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS has utilized oxalic acid to accomplish this task. Since the waste tanks are constructed of carbon steel, a significant amount of corrosion may occur. Although the total amount of corrosion may be insignificant for a short contact time, a significant amount of hydrogen may be generated due to the corrosion reaction. Linear polarization resistance and anodic/cathodic polarization tests were performed to investigate the corrosion behavior during the process. The effect of process variables such as temperature, agitation, aeration, sample orientation, light as well as surface finish on the corrosion behavior were evaluated. The results of the tests provided insight into the corrosion mechanism for the iron-oxalic acid system.

  19. The effect of sulfuric acid on pore initiation in anodic alumina formed in oxalic acid

    Directory of Open Access Journals (Sweden)

    Behnam Hafezi

    2014-07-01

    Full Text Available In this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. Effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. Electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (SEM techniques, respectively. Effect of electrolyte composition on current density was discussed. In various electrical potentials, electrolyte composition had different effects on current density. Addition of sulfuric acid into oxalic acid increased porosity. Also, distribution of pore size and pore diameter were influenced by presence of sulfuric acid. Effect of electrolyte composition on the morphology of aluminum surface layer depended on the electric potential. Current density and porosity of aluminum surface layer was decreased by heat pretreatment.

  20. Microstructure of Yttria-Doped Ceria as a Function of Oxalate Co-Precipitation Synthesis Conditions

    Science.gov (United States)

    Brissonneau, Laurent; Mathieu, Aurore; Tormos, Brigitte; Martin-Garin, Anna

    2016-12-01

    In sodium fast reactors (SFR), dissolved oxygen in sodium can be monitored via potentiometric sensors with an yttria-doped thoria electrolyte. Yttria-doped ceria (YDC) was chosen as a surrogate material to validate the process of such sensors. The material must exhibit high density and a fine grain microstructure to be resistant to the corrosion by liquid sodium and thermal shocks. Thus, the oxalic co-precipitation route was chosen to avoid milling steps that could bring impurity incorporation which is suspected to induce grain boundary corrosion in sodium. The powder and sintered pellets examination show that the synthesis conditions are of primary importance on the process yield, the oxalate powder microstructure and, eventually, on the ceramic density and microstructure. The impurity content was limited by controlling the synthesis, calcination, and sintering steps.

  1. Room temperature magnetism in zinc nano ferrite synthesized by a novel oxalate-ceramic method

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Kapil K., E-mail: getdrkapil@yahoo.com [Department of Physics, Wilson College, Chowpatty, Mumbai 400 007 (India); Department of Physics and National Centre for Nanosciences and Nanotechnology, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Niwate, Yogesh S.; Garje, Shivram S. [Department of Chemistry, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Kothari, D.C. [Department of Physics and National Centre for Nanosciences and Nanotechnology, University of Mumbai, Santacruz (E), Mumbai 400 098 (India)

    2015-07-01

    Zinc nano-ferrite has been synthesized using a novel oxalate-ceramic method and its magnetic properties are reported in this paper. The hysteresis loop recorded at 300 K exhibits ferrimagnetic behavior. The Neel temperature was found to be 557 K. The AC susceptibility curve also indicates ferrimagnetic behavior. The temperature dependent magnetization curves, obtained in the temperature range of 4–300 K, show spin glass behavior. Using this method of synthesis large quantity of ferrite can be synthesized therefore this method can become useful technique for industrial scale production. - Highlights: • Oxalate-ceramic method is a novel technique to synthesize spinel ferrites. • Zinc ferrite synthesized by this technique are in nanocrystalline form with average crystallite size of 32 nm. • Neel temperature of zinc ferrite is found to be 557 K. • Different magnetic behavior in different temperature regime.

  2. IN-SITU MONITORING OF CORROSION DURING A LABORATORY SIMULATION OF OXALIC ACID CHEMICAL CLEANING

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; John Mickalonis, J; Michael Poirier, M; John Pareizs, J; David Herman, D; David Beam, D; Samuel Fink, S; Fernando Fondeur, F

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS used oxalic acid to accomplish this task. To better understand the conditions of oxalic acid cleaning of the carbon steel waste tanks, laboratory simulations of the process were conducted to determine the corrosion rate of carbon steel and the generation of gases such as hydrogen and carbon dioxide. Open circuit potential measurements, linear polarization measurements, and coupon immersion tests were performed in-situ to determine the corrosion behavior of carbon steel during the demonstration. Vapor samples were analyzed continuously to determine the constituents of the phase. The combined results from these measurements indicated that in aerated environments, such as the tank, that the corrosion rates are manageable for short contact times and will facilitate prediction and control of the hydrogen generation rate during operations.

  3. Photoelectrocatalytic Degradation of Sodium Oxalate by TiO2/Ti Thin Film Electrode

    Directory of Open Access Journals (Sweden)

    Chen-Yu Chang

    2012-01-01

    Full Text Available The photocatalytically active TiO2 thin film was deposited on the titanium substrate plate by chemical vapor deposition (CVD method, and the photoelectrocatalytic degradation of sodium oxalate was investigated by TiO2 thin film reactor prepared in this study with additional electric potential at 365 nm irradiation. The batch system was chosen in this experiment, and the controlled parameters were pH, different supporting electrolytes, applied additional potential, and different electrolyte solutions that were examined and discussed. The experimental results revealed that the additional applied potential in photocatalytic reaction could prohibit recombination of electron/hole pairs, but the photoelectrocatalytic effect was decreased when the applied electric potential was over 0.25 V. Among the electrolyte solutions added, sodium sulfate improved the photoelectrocatalytic effect most significantly. At last, the better photoelectrocatalytic degradation of sodium oxalate occurred at pH 3 when comparing the pH influence.

  4. Catalytic ozonation of oxalate with a cerium supported palladium oxide: An efficient degradation not relying on hydroxyl radical oxidation

    KAUST Repository

    Zhang, Tao

    2011-11-01

    The cerium supported palladium oxide (PdO/CeO 2) at a low palladium loading was found very effective in catalytic ozonation of oxalate, a probe compound that is difficult to be efficiently degraded in water with hydroxyl radical oxidation and one of the major byproducts in ozonation of organic matter. The oxalate was degraded into CO 2 during the catalytic ozonation. The molar ratio of oxalate degraded to ozone consumption increased with increasing catalyst dose and decreasing ozone dosage and pH under the conditions of this study. The maximum molar ratio reached around 1, meaning that the catalyst was highly active and selective for oxalate degradation in water. The catalytic ozonation, which showed relatively stable activity, does not promote hydroxyl radical generation from ozone. Analysis with ATR-FTIR and in situ Raman spectroscopy revealed that 1) oxalate was adsorbed on CeO 2 of the catalyst forming surface complexes, and 2) O 3 was adsorbed on PdO of the catalyst and further decomposed to surface atomic oxygen (*O), surface peroxide (*O 2), and O 2 gas in sequence. The results indicate that the high activity of the catalyst is related to the synergetic function of PdO and CeO 2 in that the surface atomic oxygen readily reacts with the surface cerium-oxalate complex. This kind of catalytic ozonation would be potentially effective for the degradation of polar refractory organic pollutants and hydrophilic natural organic matter. © 2011 American Chemical Society.

  5. Oxalate Accumulation as Regulated by Nitrogen Forms and Its Relationship to Photosynthesis in Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Xiu-Mei JI; Xin-Xiang PENG

    2005-01-01

    Four-leaf rice seedlings (Oryza sativa L.), which had been cultivated in Kimura B complete nutrient solution, were treated with two nitrogen forms by replacing the nitrogen element in the complete solution with sole nitrate or ammonium (2.86 mmol/L). Nitrate-N nutrition tended to increase oxalate content in all parts of the plant, including the leaves, stems, roots, and root exudates, whereas ammonium had the opposite effect. Consequently, marked differences in oxalate content were observed between the two treatments throughout the time tested (0--12 d), with maximal differences of approximately 12-fold at 6 d after treatment. Photosynthetic/respiratory parameters were examined over time simultaneously with changes in oxalate content. Net photosynthetic rate, chlorophyll fluorescence parameters (i.e. maximal photochemical efficiency (Fv/Fm) and photochemical quantum yields of photosystem (PS)Ⅱ (φ PSⅡ)), and respiratory rate were not significantly different between plants treated with the two nitrogen forms, although ammonium-fed plants had apparently higher leaf chlorophyll content than nitrate-fed plants. Leaf glucose content was altered little, but the content of fructose, sucrose, and total soluble sugar was significantly higher in the leaves of ammonium-fed plants than nitrate-fed plants, The results indicate that nitrate/ammonium may serve as efficient regulators of oxalate accumulation owing to regulation of metabolism in rice leaves rather than oxalate downward transfer and root excretion, and that photosynthetic metabolism is not directly correlated with the regulation of oxalate accumulation in rice plants.

  6. Reversal of Gastric Bypass Resolves Hyperoxaluria and Improves Oxalate Nephropathy Secondary to Roux-en-Y Gastric Bypass

    Science.gov (United States)

    Agrawal, Varun; Wilfong, Jonathan B.; Rich, Christopher E.; Gibson, Pamela C.

    2016-01-01

    Hyperoxaluria after Roux-en-Y gastric bypass (RYGB) increases the risk for kidney injury. Medical therapies for hyperoxaluria have limited efficacy. A 65-year-old female was evaluated for acute kidney injury [AKI, serum creatinine (Cr) 2.1 mg/dl, baseline Cr 1.0 mg/dl]. She did not have any urinary or gastrointestinal symptoms or exposure to nephrotoxic agents. Sixteen months prior to this evaluation, she underwent RYGB for morbid obesity. Her examination was unremarkable for hypertension or edema and there was no protein or blood on urine dipstick. Kidney biopsy revealed acute tubulointerstitial nephritis with oxalate crystals in tubules. The concurrent finding of severe hyperoxaluria (urine oxalate 150 mg/day) confirmed the diagnosis of oxalate nephropathy. Despite medical management of hyperoxaluria, her AKI worsened. Laparoscopic reversal of RYGB was performed and within 1 month, her hyperoxaluria resolved (urine oxalate 20 mg/day) and AKI improved (Cr 1.7 mg/dl). Surgical reversal of RYGB may be considered in patients with oxalate nephropathy at high risk of progression who fail medical therapy. Physicians need to be aware of the possibility of oxalate nephropathy after RYGB and promptly treat the hyperoxaluria to halt further kidney damage. PMID:27781207

  7. Preparation of Porous Alumina Film on Aluminum Substrate by Anodization in Oxalic Acid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Self-ordering of the cell arrangement of the anodic porous alumina was prepared in oxalic acid solution at a constant potential of 40V and at a temperature of 20°C. The honeycomb structure made by one step anodization method and two step anodization method is different.Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.

  8. Synthesis of Diethyl Oxalate by a Coupling—Regeneration Reaction of Carbon Monoxide

    Institute of Scientific and Technical Information of China (English)

    FandongMeng; GenhuiXu; 等

    2002-01-01

    This article describes a process for the synthesis of diethyl oxalate by a copling reaction of carbon monoxide,catalyzed by palladium in the presence of ethyl nitrite ,The kinetics and mechanism of the coupling and regeneration reaction are also discussed ,This paper presents the results of a scale-up test of the catalyst and the process based on an a priori computer simulation.

  9. Use of oxalic acid to control Varroa destructor in honeybee (Apis mellifera L.) colonies

    OpenAIRE

    Akyol, Ethem; YENİNAR, Halil

    2009-01-01

    This study was carried out to determine the effects of oxalic acid (OA) on reducing Varroa mite (Varroa destructor) populations in honeybee (Apis mellifera L.) colonies in the fall. Twenty honeybee colonies, in wooden Langstroth hives, were used in this experiment. Average Varroa infestation levels (%) of the OA and control groups were 25.87% and 24.57% on adult workers before the treatments. The OA treatments were applied twice, on 3 November and 13 November 2006. Average Varroa infestation ...

  10. Mediation of calcium oxalate crystal growth on human kidney epithelial cells with different degrees of injury

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shen [Graduate School of Southern Medical University, Guangzhou 510515 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Su Zexuan, E-mail: suz2008@126.com [The First Affiliated Hospital, Jinan University, Guangzhou 510632 (China); Yao Xiuqiong; Peng Hua; Deng Suiping [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Ouyang Jianming, E-mail: toyjm@jnu.edu.cn [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)

    2012-05-01

    The current study examined the role of injured human kidney tubular epithelial cell (HKC) in the mediation of formation of calcium oxalate (CaOxa) crystals by means of scanning electronic microscopy and X-ray diffraction. HKC was injured using different concentrations of H{sub 2}O{sub 2}. Cell injury resulted in a significant decrease in cell viability and superoxide dismutase (SOD) concentration and an increase in the level of malondialdehyde (MDA) and expression of osteopontin (OPN). Injured cells not only promote nucleation and aggregation of CaOxa crystals, but also induce the formation of calcium oxalate monohydrate (COM) crystals that strongly adhere to cells. These results imply that injured HKCs promote stone formation by providing more nucleating sites for crystals, promoting the aggregation of crystals, and inducing the formation of COM crystals. - Graphical abstract: Injured cells promote nucleation and aggregation of CaOxa crystals, induce the formation of calcium oxalate monohydrate (COM) crystals. Highlights: Black-Right-Pointing-Pointer A direct nucleation and growth of CaOxa crystals on both normal and injured cells. Black-Right-Pointing-Pointer Stronger green fluorescence, i.e. OPN expression, was seen on the injury cell surface Black-Right-Pointing-Pointer Injured cells promote nucleation and aggregation of CaOxa crystals. Black-Right-Pointing-Pointer Injured cells induce the formation of calcium oxalate monohydrate crystals. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} decrease cell viability in a dose-dependent manner at 0.1-1 mmol/L.

  11. Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.

    2002-01-01

    Full Text Available Dietary calcium lowers the risk of nephrolithiasis due to a decreased absorption of dietary oxalate that is bound by intestinal calcium. The aim of the present study was to evaluate oxaluria in normocalciuric and hypercalciuric lithiasic patients under different calcium intake. Fifty patients (26 females and 24 males, 41 ± 10 years old, whose 4-day dietary records revealed a regular low calcium intake (<=500 mg/day, received an oral calcium load (1 g/day for 7 days. A 24-h urine was obtained before and after load and according to the calciuria under both diets, patients were considered as normocalciuric (NC, N = 15, diet-dependent hypercalciuric (DDHC, N = 9 or diet-independent hypercalciuric (DIHC, N = 26. On regular diet, mean oxaluria was 30 ± 14 mg/24 h for all patients. The 7-day calcium load induced a significant decrease in mean oxaluria compared to the regular diet in NC and DIHC (20 ± 12 vs 26 ± 7 and 27 ± 18 vs 32 ± 15 mg/24 h, respectively, P<0.05 but not in DDHC patients (22 ± 10 vs 23 ± 5 mg/24 h. The lack of an oxalate decrease among DDHC patients after the calcium load might have been due to higher calcium absorption under higher calcium supply, with a consequent lower amount of calcium left in the intestine to bind with oxalate. These data suggest that a long-lasting regular calcium consumption <500 mg was not associated with high oxaluria and that a subpopulation of hypercalciuric patients who presented a higher intestinal calcium absorption (DDHC tended to hyperabsorb oxalate as well, so that oxaluria did not change under different calcium intake.

  12. Isothermal titration calorimetry uncovers substrate promiscuity of bicupin oxalate oxidase from Ceriporiopsis subvermispora

    Directory of Open Access Journals (Sweden)

    Hassan Rana

    2016-03-01

    Full Text Available Isothermal titration calorimetry (ITC may be used to determine the kinetic parameters of enzyme-catalyzed reactions when neither products nor reactants are spectrophotometrically visible and when the reaction products are unknown. We report here the use of the multiple injection method of ITC to characterize the catalytic properties of oxalate oxidase (OxOx from Ceriporiopsis subvermispora (CsOxOx, a manganese dependent enzyme that catalyzes the oxygen-dependent oxidation of oxalate to carbon dioxide in a reaction coupled with the formation of hydrogen peroxide. CsOxOx is the first bicupin enzyme identified that catalyzes this reaction. The multiple injection ITC method of measuring OxOx activity involves continuous, real-time detection of the amount of heat generated (dQ during catalysis, which is equal to the number of moles of product produced times the enthalpy of the reaction (ΔHapp. Steady-state kinetic constants using oxalate as the substrate determined by multiple injection ITC are comparable to those obtained by a continuous spectrophotometric assay in which H2O2 production is coupled to the horseradish peroxidase-catalyzed oxidation of 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid and by membrane inlet mass spectrometry. Additionally, we used multiple injection ITC to identify mesoxalate as a substrate for the CsOxOx-catalyzed reaction, with a kinetic parameters comparable to that of oxalate, and to identify a number of small molecule carboxylic acid compounds that also serve as substrates for the enzyme.

  13. Oxidation of ferrocene by thiocyanic acid in the presence of ammonium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Ruslin, Farah bt; Yamin, Bohari M. [School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Malaysia)

    2014-09-03

    A flake-like crystalline salt was obtained from the reaction of ferrocene, oxalic acid and ammonium thiocyanate in ethanol The elemental analysis and spectroscopic data were in agreement with the preliminary X-ray molecular structure. The compound consists of four ferrocenium moieties and a counter anion consisting of two (tetraisothiocyanato)iron(III) linked by an oxalato bridging group in such a way that both iron central atoms adopt octahedral geometries.

  14. Growth and study of barium oxalate single crystals in agar gel

    Indian Academy of Sciences (India)

    P V Dalal; K B Saraf

    2006-10-01

    Barium oxalate was grown in agar gel at ambient temperature. The effect of various parameters like gel concentration, gel setting time and concentration of the reactants on the growth of these crystals was studied. Prismatic platy shaped spherulites and dendrites were obtained. The grown crystals were characterized by X-ray powder diffractometry, infrared spectroscopy, thermogravimetric and differential thermal analysis. An attempt is made to explain the spherulitic growth mechanism.

  15. Kinetics and mechanism of the oxidation of formic and oxalic acids by benzyltrimethylammonium dichloroiodate

    Indian Academy of Sciences (India)

    Poonam Gupta; Seema Kothari

    2001-04-01

    The oxidation of formic and oxalic acids by benzyltrimethylammonium dichloroiodate (BTMACI), in the presence of zinc chloride, leads to the formation of carbon dioxide. The reaction is first order with respect to BTMACI, zinc chloride and organic acid. Oxidation of deuteriated formic acid indicates the presence of a kinetic isotope effect. Addition of benzyltrimethylammonium chloride enhances the rate. It is proposed that the reactive oxidizing species is [(PhCH2Me3N)+ (IZn2Cl6)−]. Suitablemechanisms have been proposed.

  16. Oscillatory bromate-oxalic acid-Ce-acetone-sulfuric acid reaction, in CSTR

    OpenAIRE

    Pereira,Janaina A. M.; Roberto B Faria

    2004-01-01

    Periodic oscillations were observed for the first time, in a CSTR, in the system bromate-oxalic acid-Ce(IV)-acetone-sulfuric acid, in a CSTR. A reaction between Ce(IV) and acetone, until now not described in the literature and occurring before the addition of the reagents to the reactor, was identified as a decisive factor for the appearing of the regular oscillations.

  17. An oxalate selective electrode based on modified PVC-membrane with tetra-butylammonium--Clinoptilolite nanoparticles.

    Science.gov (United States)

    Hoseini, Zohre; Nezamzadeh-Ejhieh, Alireza

    2016-03-01

    A modified PVC-membrane electrode with tetra-butylammonium bromide - Clinoptilolite nano-particles (TBA-NCP) showed good Nernstian slope (29.9±0.6 mV per decade of oxalate concentration) in concentration range of 3.1×10(-7)-8.3×10(-1) mol L(-1) with a detection limit of 1.5×10(-7) mol L(-1). The best performance was obtained with a membrane composition of 31.5% PVC, 62.5% DOP and 6% TBA-NCP in the temperature range of 20-35 °C and the pH range of 4-9. The fast response time and good reproducibility over a period of 3 months are other characteristics of the sensor. The proposed electrode was successfully used as an indicator electrode in titration of oxalate ions with CaCl2 solution. The proposed electrode was also used in direct potentiometric determination of oxalate in many real samples such as: mushroom, black and green tea, spinach and beet.

  18. Oxalate-containing phytocomplexes as dentine desensitisers: an in vitro study.

    Science.gov (United States)

    Sauro, Salvatore; Gandolfi, Maria Giovanna; Prati, Carlo; Mongiorgi, Romano

    2006-08-01

    It is known that pulpal fluid movement through dentinal tubules causes dentinal hypersensitivity and that pain can be reduced by decreasing the fluid flow. The aim of this study was to evaluate dentinal permeability and morphology after a single exposure to experimental phytocomplex substances containing oxalates. The treatments tested were experimental pastes, gels and solutions of phytocomplexes (extracted from rhubarb, spinach and mint), an experimental paste containing 5% potassium oxalate, and two commercial toothpastes recommended for dentinal hypersensitivity (Elmex and Sensodyne). Dentine discs from human third molars were used in this study. Each sample was brushed for 3 min with each treatment in order to test reductions in dentinal permeability. Each treated sample was challenged with orthophosphoric acid for 90 s to determine changes in dentinal permeability and the sensitivity of treatments to acid challenge. Scanning electron microscopy was used to analyse the samples. This study found that spinach and rhubarb phytocomplex treatments reduced dentinal permeability by occluding dentinal tubules through formation of calcium oxalate crystals. These results indicate that phytocomplexes extracted from rhubarb and spinach, used in different formulations, should be effective for topical treatment of dentinal hypersensitivity.

  19. Stone size limits the use of Hounsfield units for prediction of calcium oxalate stone composition.

    Science.gov (United States)

    Stewart, Gregory; Johnson, Lewis; Ganesh, Halemane; Davenport, Daniel; Smelser, Woodson; Crispen, Paul; Venkatesh, Ramakrishna

    2015-02-01

    To evaluate the role of stone size in predicting urinary calculus composition using Hounsfield units on noncontrasted computed tomography (CT) scan. A retrospective review was performed for all patients who underwent ureteroscopy or percutaneous nephrolithotomy during a 1-year period, had a stone analysis performed, and had CT imaging available for review. All CT scans were reviewed by a board-certified radiologist. Variables evaluated included age, sex, body mass index, stone size, stone location, Hounsfield units (HUs), and stone composition. We identified a total of 91 patients (41 men and 50 women) with CT imaging and stone analysis available for review. Stone analysis showed 41 calcium oxalate monohydrate (CaOxMH), 13 calcium oxalate dihydrate, 29 calcium phosphate, 5 uric acid, 2 struvite, and 1 cystine stone. Average age was 46 years, and average body mass index was 32 kg/m2. Measured HUs varied significantly with size for CaOxMH and calcium oxalate dihydrate stones (P values 10 mm) stones (55%). For calcium stones, the ability of CT HUs to predict stone composition was limited, likely due to the mixed stone composition. Within a cohort of CaOxMH stone formers, measured HUs varied linearly with stone size. All stones <5 mm were below thresholds for CaOxMH composition. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. EFFECT OF NATURAL IRON OXIDE, HYDROGEN PEROXIDE, AND OXALIC ACID ON PHOTOCHEMICAL DEGRADATION OF 2-CHLOROPHENOL

    Directory of Open Access Journals (Sweden)

    W REMACHE

    2014-07-01

    Full Text Available The voluntary or accidental release of chemical compounds in the environment is a major cause of pollution of natural waters. Most of chlorophenols are toxic and hardly biodegradable and are difficult to remove from the environment. Therefore, it is important to find innovative and economical methods for the safe and complete destruction. The objective of this work is to test the activity photocatalytic of natural iron oxide (NIO in the photodegradation of 2-chlorophenol (2-CP. The analysis chromatographic with HPLC of solutions exposed under UV irradiation revealed that the degradation of 2-CP was negligible under the condition of using only natural iron oxide. The effect of wavelength on photoreactivity of NIO was also investigated in this process: at high wavelength thus at low energy the efficiency of degradation is important. We have also investigated the activation of NIO by hydrogen peroxide and oxalic acid, The results showed that the photodegradation of 2-CP under UVA irradiation could be enhanced greatly in the presence of oxalate. 2-CP was completly removed after 240 minutes of irradiation when the concentration of oxalic acid is equal to 2.10-3 M. The use of 2.0 % of isopropanol as a scavenger confirmed the intervention of hydroxyl radicals in the photodegradation of 2-CP.

  1. Circular patterns of calcium oxalate crystals induced by defective Langmuir-Blodgett film

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett(LB)films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate(COM)were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine(DPPC)LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size(5-20μm)increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.

  2. Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-01

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodium aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the tests showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.

  3. Reactivity of metal-oxalate EUV resists as a function of the central metal

    Science.gov (United States)

    Grzeskowiak, Steven; Narasimhan, Amrit; Murphy, Michael; Napolitano, Lee; Freedman, Daniel A.; Brainard, Robert L.; Denbeaux, Greg

    2017-03-01

    the microelectronics industry. Traditional EUV photoresists have been composed of organic compounds which are moderately transparent to EUV. Resist stochastics and sensitivity can be improved by increasing the number of photons absorbed. Molecular organometallic resists are a type of metal containing resist aimed at improving EUV absorption. This work focuses on studying the role of the metal center (Metal = Co, Fe, Cr) in an oxalate complex by comparing the number of absorbed photons and the photoelectron reactivity in each compound. In the study presented here, the EUV absorption coefficients are determined experimentally by measuring the transmission through a resist coated on a silicon nitride membrane using an Energetiq EQ-10M xenon plasma EUV source. Additionally, the photochemistry is evaluated by monitoring outgassing reaction products. This particular resist platform eliminates oxalate ligands when exposed to electrons or EUV photons resulting in a solubility difference between the exposed and unexposed regions. In the process, carbon dioxide is produced and is monitored using mass spectrometry, where quantitative values are obtained using a calibration technique. For the metal oxalate complexes studied, the absorption of EUV changed minimally due to the low concentrations of metal atoms. However, EUV and electron reactivity greatly changed between the three compounds likely due to the reducibility of the metal center. A correlation is shown between Esize and the reducibility of each photoresist.

  4. Efficiency and resistance of the artificial oxalate protection treatment on marble against chemical weathering

    Energy Technology Data Exchange (ETDEWEB)

    Doherty, B. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Pamplona, M. [Centro de Petrologia e Geoquimica do Instituto Superior Tecnico Universidade Tecnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal); Selvaggi, R. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Miliani, C. [Istituto CNR di Scienze e Tecnologie Molecolari (ISTM), Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy)]. E-mail: miliani@thch.unipg.it; Matteini, M. [CNR Istituto, Conservazione e Valorizzazione dei Beni Culturali (ICVBC), Via Madonna del Piano, 10, Edifico C-50019, Florence (Italy); Sgamellotti, A. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Istituto CNR di Scienze e Tecnologie Molecolari (ISTM), Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Brunetti, B. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy)

    2007-03-15

    The artificial oxalate protection method was analyzed in laboratory experiments in order to achieve an optimum treatment application and concentration giving rise to its most effective protective nature. Spectroscopic (Fourier transform infrared, Micro-Raman and UV-vis colorimetry), microscopic (scanning electron microscope) and contact-angle analyses were carried out to characterize Carrara marble samples before and after application of the treatment to validate its efficiency. The resistance effects against chemical weathering were subsequently observed in a lab-controlled weak acid rain experiment. An acid spray at pH 5.5, representative of normal rain was used to provoke degrade of natural marble, marble treated with the artificial oxalate protective at concentrations of 0.4 and 5% and marble treated with a commercial organic silicon product. Run-off solutions sampled at timely intervals were tested for any change in pH followed by ion chromatography measurements for the presence of calcium ions in solution. The chromatography results of the oxalate treatment applied at a 5% concentration are analogous to an organic commercial product indicating its validity as a method for the conservation of carbonate substrates conferring protection to stone materials against acid environments.

  5. Elemental Content of Calcium Oxalate Stones from a Canine Model of Urinary Stone Disease.

    Directory of Open Access Journals (Sweden)

    David W Killilea

    Full Text Available One of the most common types of urinary stones formed in humans and some other mammals is composed of calcium oxalate in ordered hydrated crystals. Many studies have reported a range of metals other than calcium in human stones, but few have looked at stones from animal models such as the dog. Therefore, we determined the elemental profile of canine calcium oxalate urinary stones and compared it to reported values from human stones. The content of 19 elements spanning 7-orders of magnitude was quantified in calcium oxalate stones from 53 dogs. The elemental profile of the canine stones was highly overlapping with human stones, indicating similar inorganic composition. Correlation and cluster analysis was then performed on the elemental profile from canine stones to evaluate associations between the elements and test for potential subgrouping based on elemental content. No correlations were observed with the most abundant metal calcium. However, magnesium and sulfur content correlated with the mineral hydration form, while phosphorous and zinc content correlated with the neuter status of the dog. Inter-elemental correlation analysis indicated strong associations between barium, phosphorous, and zinc content. Additionally, cluster analysis revealed subgroups within the stones that were also based primarily on barium, phosphorous, and zinc. These data support the use of the dog as a model to study the effects of trace metal homeostasis in urinary stone disease.

  6. Photoluminescence properties of heat-treated porous alumina films formed in oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Vrublevsky, I., E-mail: vrublevsky@bsuir.edu.b [Belarusian State University of Informatics and Radioelectronics Minsk, Department of Micro and Nanoelectronics, 220013 Minsk (Belarus); Chernyakova, K. [Belarusian State University of Informatics and Radioelectronics Minsk, Department of Micro and Nanoelectronics, 220013 Minsk (Belarus); Ispas, A.; Bund, A.; Gaponik, N.; Dubavik, A. [Technische Universitaet Dresden, Physikalische Chemie und Elektrochemie, 01062 Dresden (Germany)

    2011-05-15

    Photoluminescence and optical properties of as-anodized and heat-treated at 500 {sup o}C porous alumina films formed in a 0.3 M oxalic acid at 40 V have been studied. The FTIR indicates that the oxalate ions are embedded in the anodic alumina as chelating bidentate structures and further heating up to 500 {sup o}C does not cause any change in ion coordination. The results of time-resolved spectroscopy show the presence of two luminescence centers both in the as-anodized and heat-treated anodic alumina films with lifetimes of about 0.25 and 4.0 ns. The F{sup +}-centers in anodic alumina are responsible for the luminescence peak at about 420 nm, with a lifetime of about 4.0 ns. The luminescence peak at about 480 nm, with lifetime of about 0.25 ns, can be attributed to the luminescence of carboxylate ions existing in bulk of anodic alumina. - Research highlights: {yields} Photoluminescence and optical properties of porous alumina films have been studied. {yields} In anodic alumina the oxalate ions are embedded as chelating bidentate structures. {yields} The results show the presence of two luminescence centers. {yields} The F{sup +}-centers are responsible for the peak at 420 nm with a lifetime of 4.0 ns. {yields} The peak at 480 nm with a lifetime of 0.25 ns can be attributed to carboxylate ions.

  7. COMPARATIVE ANALYSIS OF OXALIC ACID PRODUCED FROM RICE HUSK AND PADDY

    Directory of Open Access Journals (Sweden)

    P.I. Oghome

    2012-09-01

    Full Text Available In this research work, comparative analysis of Oxalic acid produced from Rice husk and Paddy was carried out in order to ascertain which waste sample produced a better yield. Nitric acid oxidation of carbohydrates was the method adopted in the production. The variable ratios of HNO3:H2SO4 used were 80:20, 70:30, 60:40, and 50:50. The variable ratio of 60:40 gave the maximum yield and at a maximum temperature of 75oC. Rice husk sample gave a percentage yield of 53.2, 64.4, 81.0, and 53.3 at temperatures of 55 oC, 65 oC, 75 oC, and 85 oC respectively. In the case of paddy a percentage yield of 53.1, 64.0, 79.9, and 52.8 at temperatures of 55 oC, 65 oC, 75 oC, and 85 oC were obtained respectively. The plots between yield and temperature at different variable ratios illustrate the dependence of yield on temperature, which was similar to a parabolic relationship and the peak value (yield was at 75 oC above which it decreased. The properties of oxalic acid from both sources were very close and compared favourably with literature. In comparing the yield, oxalic acid produced from Rice husk gave higher yield than that from Paddy.

  8. Vibrational spectra and non linear optical proprieties of L-histidine oxalate: DFT studies

    Science.gov (United States)

    Ahmed, A. Ben; Elleuch, N.; Feki, H.; Abid, Y.; Minot, C.

    2011-08-01

    This paper presents the results of our calculations on the geometric parameters, vibrational spectra and hyperpolarizability of a nonlinear optical material L-histidine oxalate. Due to the lack of sufficiently precise information on geometric structure in literature, theoretical calculations were preceded by re-determination of the crystal X-ray structure. Single crystal of L-histidine oxalate has been growing by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in the non-Centro symmetric space group P2 12 12 1 of orthorhombic system. The FT-IR and Raman spectra of L-histidine oxalate were recorded and analyzed. The vibrational wave numbers were examined theoretical with the aid of Gaussian98 package of programs using the DFT//B3LYP/6-31G(d) level of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands obtained in IR and Raman spectroscopy of the studied compound. The geometrical parameters of the title compound are in agreement with the values of similar structures. To investigate microscopic second order non-linear optical NLO behaviour of the examined complex, the electric dipole μtot, the polarizability αtot and the hyperpolarizability βtot were computed using DFT//B3LYP/6-31G(d) method. According to our calculation, the title compound exhibits non-zero βtot value revealing microscopic second order NLO behaviour.

  9. Circular patterns of calcium oxalate crystals induced by defective Langmuir-Blodgett film

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The injury of the renal epithelial cell membrane can promote the nucleation of nascent crystals, as well as adhesion of crystals on it. It thus accelerates the formation of renal calculi. In this paper, the defective Langmuir-Blodgett (LB) films were used as a model system to simulate the injured renal epithelial cell membrane. The microcosmic structure of the defective LB film and the molecular mechanism of the effect of this film on nucleation, growth, deposited patterns and adhesion of calcium oxalate monohydrate (COM) were investigated. The circular defective domains were formed in dipalmitoylphosphatidylcholine (DPPC) LB film after the film was treated by potassium oxalate. These domains could induce ring-shaped patterns of COM crystals. In comparison, the LB film without pretreatment by potassium oxalate only induced random growth of hexagonal COM crystals. As the crystallization time increased, the size of COM crystals in the patterns increased, the crystal patterns changed from empty circles to solid circles, and the number of the circular patterns with small size (5-20 μm) increased. The results would shed light on the molecular mechanism of urolithiasis induced by injury of the renal epithelial membrane at the molecular and supramolecular level.

  10. Calcium oxalate crystals: an integral component of the Sclerotinia sclerotiorum/Brassica carinata pathosystem.

    Science.gov (United States)

    Uloth, Margaret B; Clode, Peta L; You, Ming Pei; Barbetti, Martin J

    2015-01-01

    Oxalic acid is an important virulence factor for disease caused by the fungal necrotrophic pathogen Sclerotinia sclerotiorum, yet calcium oxalate (CaOx) crystals have not been widely reported. B. carinata stems were infected with S. sclerotiorum and observed using light microscopy. Six hours post inoculation (hpi), CaOx crystals were evident on 46% of stem sections and by 72 hpi on 100%, demonstrating that the secretion of oxalic acid by S. sclerotiorum commences before hyphal penetration. This is the first time CaOx crystals have been reported on B. carinata infected with S. sclerotiorum. The shape of crystals varied as infection progressed. Long tetragonal rods were dominant 12 hpi (68% of crystal-containing samples), but by 72 hpi, 50% of stems displayed bipyramidal crystals, and only 23% had long rods. Scanning electron microscopy from 24 hpi revealed CaOx crystals in all samples, ranging from tiny irregular crystals (Crystal morphology encompassed various forms, including tetragonal prisms, oval plates, crystal sand, and druses. Large conglomerates of CaOx crystals were observed in the hyphal mass 72 hpi and these are proposed as a strategy of the fungus to hold and detoxify Ca2+ions. The range of crystal morphologies suggests that S. sclerotiorum growth and infection controls the form taken by CaOx crystals.

  11. An understanding of renal stone development in a mixed oxalate-phosphate system.

    Science.gov (United States)

    Guan, Xiangying; Wang, Lijun; Dosen, Anja; Tang, Ruikang; Giese, Rossman F; Giocondi, Jennifer L; Orme, Christine A; Hoyer, John R; Nancollas, George H

    2008-07-15

    The in vivo formation of calcium oxalate concretions having calcium phosphate nidi is simulated in an in vitro (37 degrees C, pH 6.0) dual constant composition (DCC) system undersaturated (sigma DCPD = -0.330) with respect to brushite (DCPD, CaHPO 4 . 2H 2O) and slightly supersaturated (sigma COM = 0.328) with respect to calcium oxalate monohydrate (COM, CaC2O4 . H2O). The brushite dissolution provides calcium ions that raise the COM supersaturation, which is heterogeneously nucleated either on or near the surface of the dissolving calcium phosphate crystals. The COM crystallites may then aggregate, simulating kidney stone formation. Interestingly, two intermediate phases, anhydrous dicalcium phosphate (monetite, CaHPO4) and calcium oxalate trihydrate (COT), are also detected by X-ray diffraction during this brushite-COM transformation. In support of clinical observations, the results of these studies demonstrate the participation of calcium phosphate phases in COM crystallization providing a possible physical chemical mechanism for kidney stone formation.

  12. Crystal growth and first crystallographic characterization of mixed uranium(IV)-plutonium(III) oxalates.

    Science.gov (United States)

    Tamain, Christelle; Arab Chapelet, Bénédicte; Rivenet, Murielle; Abraham, Francis; Caraballo, Richard; Grandjean, Stéphane

    2013-05-06

    The mixed-actinide uranium(IV)-plutonium(III) oxalate single crystals (NH4)0.5[Pu(III)0.5U(IV)0.5(C2O4)2·H2O]·nH2O (1) and (NH4)2.7Pu(III)0.7U(IV)1.3(C2O4)5·nH2O (2) have been prepared by the diffusion of different ions through membranes separating compartments of a triple cell. UV-vis, Raman, and thermal ionization mass spectrometry analyses demonstrate the presence of both uranium and plutonium metal cations with conservation of the initial oxidation state, U(IV) and Pu(III), and the formation of mixed-valence, mixed-actinide oxalate compounds. The structure of 1 and an average structure of 2 were determined by single-crystal X-ray diffraction and were solved by direct methods and Fourier difference techniques. Compounds 1 and 2 are the first mixed uranium(IV)-plutonium(III) compounds to be structurally characterized by single-crystal X-ray diffraction. The structure of 1, space group P4/n, a = 8.8558(3) Å, b = 7.8963(2) Å, Z = 2, consists of layers formed by four-membered rings of the two actinide metals occupying the same crystallographic site connected through oxalate ions. The actinide atoms are nine-coordinated by oxygen atoms from four bidentate oxalate ligands and one water molecule, which alternates up and down the layer. The single-charged cations and nonbonded water molecules are disordered in the same crystallographic site. For compound 2, an average structure has been determined in space group P6/mmm with a = 11.158(2) Å and c = 6.400(1) Å. The honeycomb-like framework [Pu(III)0.7U(IV)1.3(C2O4)5](2.7-) results from a three-dimensional arrangement of mixed (U0.65Pu0.35)O10 polyhedra connected by five bis-bidentate μ(2)-oxalate ions in a trigonal-bipyramidal configuration.

  13. Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    STALLINGS, MARY

    2004-07-08

    This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalic acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the untreated

  14. Risk factors associated with calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States.

    Science.gov (United States)

    Okafor, Chika C; Lefebvre, Sandra L; Pearl, David L; Yang, Mingyin; Wang, Mansen; Blois, Shauna L; Lund, Elizabeth M; Dewey, Cate E

    2014-08-01

    Calcium oxalate urolithiasis results from the formation of aggregates of calcium salts in the urinary tract. Difficulties associated with effectively treating calcium oxalate urolithiasis and the proportional increase in the prevalence of calcium oxalate uroliths relative to other urolith types over the last 2 decades has increased the concern of clinicians about this disease. To determine factors associated with the development of calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States, a retrospective case-control study was performed. A national electronic database of medical records of all dogs evaluated between October 1, 2007 and December 31, 2010 at 787 general care veterinary hospitals in the United States was reviewed. Dogs were selected as cases at the first-time diagnosis of a laboratory-confirmed urolith comprised of at least 70% calcium oxalate (n=452). Two sets of control dogs with no history of urolithiasis diagnosis were randomly selected after the medical records of all remaining dogs were reviewed: urinalysis examination was a requirement in the selection of one set (n=1808) but was not required in the other set (n=1808). Historical information extracted included urolith composition, dog's diet, age, sex, neuter status, breed size category, hospital location, date of diagnosis, and urinalysis results. Multivariable analysis showed that the odds of first-time diagnosis of calcium oxalate urolithiasis were significantly (P30 mg/dL (OR: 1.55, 1.04-2.30). Patient demographics and urinalysis results are important factors that can support risk assessment and early identification of canine oxalate urolithiasis. Therefore, periodic urolith screening and monitoring of urine parameters should be encouraged for dogs at risk of developing these uroliths.

  15. Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

    Science.gov (United States)

    Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

    2012-11-01

    The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil.

  16. Detection of fluorescent labelled oligonucleotides using oxalate chemiluminiscence. Estudio de la deteccion de oligonucleotidos marcados con compuestos fluorescentes utilizando la quimioluminiscencia de los esteres del acido oxalico

    Energy Technology Data Exchange (ETDEWEB)

    Eritia, R. (Barcelona Univ. (Spain). Dept. de Quimica Organica); Johnson, D.; Paige, J.; Walker, P.; Kaplan, B. (Beckman Research Institute of City of Hope, CA (USA))

    1989-01-01

    The preparation and characterization of oligonucleotides containing fluorescent compounds at the 5' terminus is described together with the utilization of oxalate chemiluminiscence for their detection. (Author)

  17. An Assessment of Engineered Calcium Oxalate Crystal Formation on Plant Growth and Development as a Step toward Evaluating Its Use to Enhance Plant Defense.

    Science.gov (United States)

    Nakata, Paul A

    2015-01-01

    The establishment of new approaches to control chewing insects has been sought not only for direct use in reducing crop loss but also in managing resistance to the pesticides already in use. Engineered formation of calcium oxalate crystals is a potential strategy that could be developed to fulfill both these needs. As a step toward this development, this study investigates the effects of transforming a non-calcium oxalate crystal accumulating plant, Arabidopsis thaliana, into a crystal accumulating plant. Calcium oxalate crystal accumulating A. thaliana lines were generated by ectopic expression of a single bacterial gene encoding an oxalic acid biosynthetic enzyme. Biochemical and cellular studies suggested that the engineered A. thaliana lines formed crystals of calcium oxalate in a manner similar to naturally occurring crystal accumulating plants. The amount of calcium oxalate accumulated in leaves also reached levels similar to those measured in the leaves of Medicago truncatula in which the crystals are known to play a defensive role. Visual inspection of the different engineered lines, however, suggested a phenotypic consequence on plant growth and development with higher calcium oxalate concentrations. The restoration of a near wild-type plant phenotype through an enzymatic reduction of tissue oxalate supported this observation. Overall, this study is a first to provide initial insight into the potential consequences of engineering calcium oxalate crystal formation in non-crystal accumulating plants.

  18. Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents

    Science.gov (United States)

    Mellman, James Kenneth

    Ureteral stents develop calcium-bearing deposits, called encrustation, that diminish their biocompatibility due to complications, such as chronic abrasion to the lumen of the ureter wall and subsequent infection. A reduction of encrustation, namely calcium oxalate, will improve the lifetime, health care costs, and infection resistance of such devices. The purpose of this research project is to study oxalate-degrading enzymes entrapped into a coating material that will control the interface to the urinary environment for ureteral stents. The coating material was a lightly crosslinked poly(2-hydroxyethyl methacrylate) (p(HEMA)) matrix in which the active enzymes were entrapped within the bulk material's free volume. The swelling of p(HEMA) films was comparable in ddH2O and urine. This hydrophilic matrix allows oxalate anions to diffuse into the bulk so that enzyme activity against oxalate can lower its local concentration, and thereby reduce the supersaturation of calcium oxalate. Oxalate oxidase (OxO) and oxalate decarboxylase (OxDc) were the oxalate-degrading enzymes examined herein. Michaelis Menten kinetic models were applied to free and immobilized enzyme activity. A substrate inhibition model was applied to OxO. The free form of OxO had a Vmax of 1.8 +/- 0.1 muM/min-mug, a km of 1.8 +/- 0.1 mM, and a ks of 35.4 +/- 3.7 mM while the immobilized form had a Vmax of 1.2 +/- 0.2 muM/min-mug, a km of 4.1 +/- 0.6 mM, and a ks of 660 +/- 140 mM. The free form of OxDc had a Vmax of 23.5 +/- 1.4 muM/min-mug and a km of 0.5 +/- 0.1 mM while the immobilized form had a Vmax of 5.0 +/- 1.9 muM/min-mug and km of 23.2 +/- 9.1 mM. The enzyme activity was measured to indicate viable application conditions for the coating, such as storing the films in urine over time. The maximum activity was shown at pH 4.2 to 4.5 and activity drops to be negligible by pH 7.0. Storing the enzyme at pH 6.1 exhibited a larger retained activity than storing at pH 4.2, yet storing in urine showed

  19. Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.

    Science.gov (United States)

    Chen, Haihan; Grassian, Vicki H

    2013-09-17

    Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface.

  20. Thermodynamics of the Complexation of Uranium(VI) by oxalate in aqueous solution at 10-70oC

    Energy Technology Data Exchange (ETDEWEB)

    Di Bernardo, Plinio; Zanonato, Pier Luigi; Tian, Guoxin; Tolazzi, Marilena; Rao, Linfeng

    2009-03-31

    The protonation reactions of oxalate (ox) and the complex formation of uranium(VI) with oxalate in 1.05 mol kg{sup -1} NaClO{sub 4} were studied at variable temperatures (10-70 C). Three U(VI)/ox complexes (UO{sub 2}ox{sub j}{sup (2-2j){sup +}} with j = 1, 2, 3) were identified in this temperature range. The formation constants and the molar enthalpies of complexation were determined by spectrophotometry and calorimetry. The complexation of uranium(VI) with oxalate ion is exothermic at lower temperatures (10-40 C) and becomes endothermic at higher temperatures (55-70 C). In spite of this, the free energy of complexation becomes more negative at higher temperatures due to increasingly more positive entropy of complexation that exceeds the increase of the enthalpy of complexation. The thermodynamic parameters at different temperatures, in conjunction with the literature data for other dicarboxylic acids, provide insight into the relative strength of U(VI) complexes with a series of dicarboxylic acids (oxalic, malonic and oxydiacetic) and rationalization for the highest stability of U(VI)/oxalate complexes in the series. The data reported in this study are of importance in predicting the migration of uranium(VI) in geological environments in the case of failure of the engineering barriers which protect waste repositories.

  1. Improving nutritional quality and fungal tolerance in soya bean and grass pea by expressing an oxalate decarboxylase.

    Science.gov (United States)

    Kumar, Vinay; Chattopadhyay, Arnab; Ghosh, Sumit; Irfan, Mohammad; Chakraborty, Niranjan; Chakraborty, Subhra; Datta, Asis

    2016-06-01

    Soya bean (Glycine max) and grass pea (Lathyrus sativus) seeds are important sources of dietary proteins; however, they also contain antinutritional metabolite oxalic acid (OA). Excess dietary intake of OA leads to nephrolithiasis due to the formation of calcium oxalate crystals in kidneys. Besides, OA is also a known precursor of β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP), a neurotoxin found in grass pea. Here, we report the reduction in OA level in soya bean (up to 73%) and grass pea (up to 75%) seeds by constitutive and/or seed-specific expression of an oxalate-degrading enzyme, oxalate decarboxylase (FvOXDC) of Flammulina velutipes. In addition, β-ODAP level of grass pea seeds was also reduced up to 73%. Reduced OA content was interrelated with the associated increase in seeds micronutrients such as calcium, iron and zinc. Moreover, constitutive expression of FvOXDC led to improved tolerance to the fungal pathogen Sclerotinia sclerotiorum that requires OA during host colonization. Importantly, FvOXDC-expressing soya bean and grass pea plants were similar to the wild type with respect to the morphology and photosynthetic rates, and seed protein pool remained unaltered as revealed by the comparative proteomic analysis. Taken together, these results demonstrated improved seed quality and tolerance to the fungal pathogen in two important legume crops, by the expression of an oxalate-degrading enzyme. © 2016 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  2. Are calcium oxalate crystals involved in the mechanism of acute renal failure in ethylene glycol poisoning?

    Science.gov (United States)

    McMartin, Kenneth

    2009-11-01

    Ethylene glycol (EG) poisoning often results in acute renal failure, particularly if treatment with fomepizole or ethanol is delayed because of late presentation or diagnosis. The mechanism has not been established but is thought to result from the production of a toxic metabolite. A literature review utilizing PubMed identified papers dealing with renal toxicity and EG or oxalate. The list of papers was culled to those relevant to the mechanism and treatment of the renal toxicity associated with either compound. ROLE OF METABOLITES: Although the "aldehyde" metabolites of EG, glycolaldehyde, and glyoxalate, have been suggested as the metabolites responsible, recent studies have shown definitively that the accumulation of calcium oxalate monohydrate (COM) crystals in kidney tissue produces renal tubular necrosis that leads to kidney failure. In vivo studies in EG-dosed rats have correlated the severity of renal damage with the total accumulation of COM crystals in kidney tissue. Studies in cultured kidney cells, including human proximal tubule (HPT) cells, have demonstrated that only COM crystals, not the oxalate ion, glycolaldehyde, or glyoxylate, produce a necrotic cell death at toxicologically relevant concentrations. COM CRYSTAL ACCUMULATION: In EG poisoning, COM crystals accumulate to high concentrations in the kidney through a process involving adherence to tubular cell membranes, followed by internalization of the crystals. MECHANISM OF TOXICITY: COM crystals have been shown to alter membrane structure and function, to increase reactive oxygen species and to produce mitochondrial dysfunction. These processes are likely to be involved in the mechanism of cell death. Accumulation of COM crystals in the kidney is responsible for producing the renal toxicity associated with EG poisoning. The development of a pharmacological approach to reduce COM crystal adherence to tubular cells and its cellular interactions would be valuable as this would decrease the renal

  3. In situ spectroscopic studies on vapor phase catalytic decomposition of dimethyl oxalate.

    Science.gov (United States)

    Hegde, Shweta; Tharpa, Kalsang; Akuri, Satyanarayana Reddy; K, Rakesh; Kumar, Ajay; Deshpande, Raj; Nair, Sreejit A

    2017-03-15

    Dimethyl Oxalate (DMO) has recently gained prominence as a valuable intermediate for the production of compounds of commercial importance. The stability of DMO is poor and hence this can result in the decomposition of DMO under reaction conditions. The mechanism of DMO decomposition is however not reported and more so on catalytic surfaces. Insights into the mechanism of decomposition would help in designing catalysts for its effective molecular transformation. It is well known that DMO is sensitive to moisture, which can also be a factor contributing to its decomposition. The present work reports the results of decomposition of DMO on various catalytic materials. The materials studied consist of acidic (γ-Al2O3), basic (MgO), weakly acidic (ZnAl2O4) and neutral surfaces such as α-Al2O3 and mesoporous precipitated SiO2. Infrared spectroscopy is used to identify the nature of adsorption of the molecule on the various surfaces. The spectroscopy study is done at a temperature of 200 °C, which is the onset of gas phase decomposition of DMO. The results indicate that the stability of DMO is lower than the corresponding acid, i.e. oxalic acid. It is also one of the products of decomposition. Spectroscopic data suggest that DMO decomposition is related to surface acidity and the extent of decomposition depends on the number of surface hydroxyl groups. Decomposition was also observed on α-Al2O3, which was attributed to the residual surface hydroxyl groups. DMO decomposition to oxalic acid was not observed on the basic surface (MgO).

  4. Vibrational spectra and non linear optical proprieties of L-histidine oxalate: DFT studies.

    Science.gov (United States)

    Ben Ahmed, A; Elleuch, N; Feki, H; Abid, Y; Minot, C

    2011-08-01

    This paper presents the results of our calculations on the geometric parameters, vibrational spectra and hyperpolarizability of a nonlinear optical material L-histidine oxalate. Due to the lack of sufficiently precise information on geometric structure in literature, theoretical calculations were preceded by re-determination of the crystal X-ray structure. Single crystal of L-histidine oxalate has been growing by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in the non-Centro symmetric space group P2(1)2(1)2(1) of orthorhombic system. The FT-IR and Raman spectra of L-histidine oxalate were recorded and analyzed. The vibrational wave numbers were examined theoretical with the aid of Gaussian98 package of programs using the DFT//B3LYP/6-31G(d) level of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands obtained in IR and Raman spectroscopy of the studied compound. The geometrical parameters of the title compound are in agreement with the values of similar structures. To investigate microscopic second order non-linear optical NLO behaviour of the examined complex, the electric dipole μ(tot), the polarizability α(tot) and the hyperpolarizability β(tot) were computed using DFT//B3LYP/6-31G(d) method. According to our calculation, the title compound exhibits non-zero β(tot) value revealing microscopic second order NLO behaviour. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  5. Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

    Institute of Scientific and Technical Information of China (English)

    OUYANG Jianming; DENG Suiping; LI Xiangping; TAN Yanhua; Bernd Tieke

    2004-01-01

    The effects of temperature and multifunctional sodium carboxylate additives on the phase composition and morphology of calcium oxalate (CaOxa) crystals grown in silica gel system were systematically investigated using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and Fourier-transform infrared spectra (FT-IR). The sodium carboxylates investigated include: monocarboxylate sodium acetate (NaAc), disodium tartrate (Na2tart), trisodium citrate (Na3cit), and the disodium salt of ethylenediaminetetraacetic acid (Na2edta). The temperature range was from 7℃ to 67℃. The crystallization temperature affects the phase compositions, the growth rate, and the morphology of CaOxa. First, the logarithm of the percentage of calcium oxalate dihydrate (COD) formed at a certain temperature (T) is proportional to the reciprocal of temperature (1/T). Second, the weight of CaOxa crystals decreases as decreasing the temperature. At a given temperature, the ability of the sodium carboxylates to induce COD follows the order: Na2edta > Na3cit > Na2tart >> NaAc. Third, the multicarboxylates can decrease the surface area of calcium oxalate monohydrate (COM).It makes the edges and tips of COM crystals blunt and oval. All the three changes, an increase of the content of COD, a decrease of the weight of CaOxa crystals, and a decrease of the surfacearea of COM crystals,can inhibit the formation of CaOxa stones. These results support the clinical use of citrates and may be helpful in elucidating the mechanisms of the formation of CaOxa calculus.

  6. Hydrothermal synthesis and characterization of new hybrid open-framework indium phosphate-oxalates

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhenxia; WENG Linhong; CHEN Jinxi; ZHAO Dongyuan

    2004-01-01

    Three new hybrid open-framework indium phosphate-oxalates,Ⅰ, Na[InPO4(C2O4)0.5]·H2OⅡ, [C2N2- H10]0.5[InPO4(C2O4)0.5]Ⅲ, [C3N2H12]0.5[In2(PO4)(HPO4)(C2- O4)]·H2O have been hydrothermally synthesized by using organic amines such as ethylamine, 1,3-diaminopropane and alkali metal ions such as Na+ as structure-directing agents (SDA). The structures of these compounds were characterized by single crystal X-ray diffraction. The structure of Ⅰ consists of InO6 octahedra that are linked by phosphate and oxalate groups to generate a three-dimensional framework with intersecting 8-membered ring (MR) channels parallel to the [100] and [010] directions. The structure of Ⅱ is similar to that of I except that its guest species are protonated ethylamines. Ⅲ is built from indiumphosphate double-six-rings second building units linked by oxalate units, resulting in large circular 16 MR channels. Single crystal X-ray diffraction measurements show that the SDA of Ⅰ-Ⅲ are located in their channels. Crystal data for these three indium phosphate-oxalates are as follows: Ⅰ, triclinic, space group: P-1 (No. 2), a = 5.5662(17)(A), b = 6.454(2) (A), c = 8.966(3) (A), α = 102.609(4)°, β = 107.319(3)°, γ = 94.426(4)°, V = 296.56(16) (A)3, Z = 2, M = 294.81, Ρcalcu = 3.301 g/cm3, R1 = 0.0275, wR2 = 0.0731. Ⅱ, triclinic, space group: P-1 (No. 2), a = 5.653(4) (A), b = 6.627(4) (A), c = 9.391(8) (A), α = 70.788(8)°, β = 75.836(12)°, γ = 89.681(9)°, V = 321.1(4) (A)3, Z = 2, M = 283.85, Ρcalcu = 2.936 g/cm3, R1= 0.0664, wR2 = 0.1572. Ⅲ, orthorhombic, space group: Pccm (No. 49), a = 10.350(2) (A), b = 12.190(2) (A), c = 13.000(3) (A), V = 1640.2(6) (A)3, Z = 4, M =272.32, Ρcalcu = 2.206 g/cm3, R1=0.0691, wR2 = 0.1831.

  7. Polyfunctional two- (2D) and three- (3D) dimensional oxalate bridged bimetallic magnets

    CERN Document Server

    Clément, R; Gruselle, M; Train, C

    2003-01-01

    We report major results concerning polyfunctional two- (2D) and three- (3D) dimensional oxalate bridged bimetallic magnets. As a consequence of their specific organization they are composed of an anionic sub-lattice and a cationic counter-part. These bimetallic polymers can accommodate various counter-cations possessing specific physical properties in addition to the magnetic ones resulting from the interactions between the metallic ions in the anionic sub-lattice. Thus, molecular magnets possessing paramagnetic, conductive and optical properties are presented in this review. Refs. 60 (author)

  8. Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate

    Directory of Open Access Journals (Sweden)

    Mouhamadou Birame Diop

    2016-08-01

    Full Text Available Single crystals of the title molecular salt, C4H7N2+·HC2O4−·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H...(O,O hydrogen bonds. The water molecules of crystallization link the chains into (10-1 bilayers, with the methyl groups of the cations organized in an isotactic manner.

  9. Role of Tamm-Horsfall protein and uromodulin in calcium oxalate crystallization

    Directory of Open Access Journals (Sweden)

    Carvalho M.

    2002-01-01

    Full Text Available One of the defenses against nephrolithiasis is provided by macromolecules that modulate the nucleation, growth, aggregation and retention of crystals in the kidneys. The aim of the present study was to determine the behavior of two of these proteins, Tamm-Horsfall and uromodulin, in calcium oxalate crystallization in vitro. We studied a group of 10 male stone formers who had formed at least one kidney stone composed of calcium oxalate. They were classified as having idiopathic nephrolithiasis and had no well-known metabolic risk factors involved in kidney stone pathogenesis. Ten normal men were used as controls, as was a group consisting of five normal women and another consisting of five pregnant women. Crystallization was induced by a fixed supersaturation of calcium oxalate and measured with a Coulter Counter. All findings were confirmed by light and scanning electron microscopy. The number of particulate material deposited from patients with Tamm-Horsfall protein was higher than that of the controls (P<0.001. However, Tamm-Horsfall protein decreased the particle diameter of the stone formers when analyzed by the mode of the volume distribution curve (P<0.002 (5.64 ± 0.55 µm compared to 11.41 ± 0.48 µm of uromodulin; 15.94 ± 3.93 µm and 12.45 ± 0.97 µm of normal men Tamm-Horsfall protein and uromodulin, respectively; 8.17 ± 1.57 µm and 9.82 ± 0.95 µm of normal women Tamm-Horsfall protein and uromodulin, respectively; 12.17 ± 1.41 µm and 12.99 ± 0.51 µm of pregnant Tamm-Horsfall protein and uromodulin, respectively. Uromodulin produced fewer particles than Tamm-Horsfall protein in all groups. Nonetheless, the total volume of the crystals produced by uromodulin was higher than that produced by Tamm-Horsfall protein. Our results indicate a different effect of Tamm-Horsfall protein and uromodulin. This dual behavior suggests different functions. Tamm-Horsfall protein may act on nucleation and inhibit crystal aggregation, while

  10. DEPOSITION TANK CORROSION TESTING FOR ENHANCED CHEMICAL CLEANING POST OXALIC ACID DESTRUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.

    2011-08-29

    An Enhanced Chemical Cleaning (ECC) process is being developed to aid in the high level waste tank closure at the Savannah River Site. The ECC process uses an advanced oxidation process (AOP) to destroy the oxalic acid that is used to remove residual sludge from a waste tank prior to closure. The AOP process treats the dissolved sludge with ozone to decompose the oxalic acid through reactions with hydroxyl radicals. The effluent from this oxalic acid decomposition is to be sent to a Type III waste tank and may be corrosive to these tanks. As part of the hazardous simulant testing that was conducted at the ECC vendor location, corrosion testing was conducted to determine the general corrosion rate for the deposition tank and to assess the susceptibility to localized corrosion, especially pitting. Both of these factors impact the calculation of hydrogen gas generation and the structural integrity of the tanks, which are considered safety class functions. The testing consisted of immersion and electrochemical testing of A537 carbon steel, the material of construction of Type III tanks, and 304L stainless steel, the material of construction for transfer piping. Tests were conducted in solutions removed from the destruction loop of the prototype ECC set up. Hazardous simulants, which were manufactured at SRNL, were used as representative sludges for F-area and H-area waste tanks. Oxalic acid concentrations of 1 and 2.5% were used to dissolve the sludge as a feed to the ECC process. Test solutions included the uninhibited effluent, as well as the effluent treated for corrosion control. The corrosion control options included mixing with an inhibited supernate and the addition of hydroxide. Evaporation of the uninhibited effluent was also tested since it may have a positive impact on reducing corrosion. All corrosion testing was conducted at 50 C. The uninhibited effluent was found to increase the corrosion rate by an order of magnitude from less than 1 mil per year (mpy

  11. Theoretical calculation of zero field splitting parameters of Cr{sup 3+} doped ammonium oxalate monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Kripal, Ram, E-mail: ram_kripal2001@rediffmail.com; Yadav, Awadhesh Kumar, E-mail: aky.physics@gmail.com

    2015-06-15

    Zero field splitting parameters (ZFSPs) D and E of Cr{sup 3+} ion doped ammonium oxalate monohydrate (AOM) are calculated with formula using the superposition model. The theoretically calculated ZFSPs for Cr{sup 3+} in AOM crystal are compared with the experimental value obtained by electron paramagnetic resonance (EPR). Theoretical ZFSPs are in good agreement with the experimental ones. The energy band positions of optical absorption spectra of Cr{sup 3+} in AOM crystal calculated with CFA package are in good match with the experimental values.

  12. INHIBITION OF CALCIUM OXALATE CRYSTALLIZATION IN-VITRO BY VARIOUS EXTRACTS OF HYPTIS SUAVEOLENS (L. POIT.

    Directory of Open Access Journals (Sweden)

    Agarwal Kumkum

    2012-03-01

    Full Text Available Hyptis suaveolens (L Poit. commonly known as Vilayati tulsi, belongs to the Mint family Lamiaceae. The inhibition of in-vitro calcium-oxalate crystal (a major component of most urinary stones formation by various extracts of Hyptis was investigated by titrimetric method. The inhibitor potency of alcohol extracts of Hyptis suaveolens (L. Poit was found to be comparable to that of cystone (a proprietary drug for dissolving kidney stones. Thus alcohol extract could be further analyzed in vivo and further characterization of its active compound could lead to the discovery of a new candidate drug for the patients with urolithiasis.

  13. The influence of dicarboxylic acids: Oxalic acid and tartaric acid on the compressive strength of glass ionomer cements

    Science.gov (United States)

    Permana, Ahmadi Jaya; Setyawati, Harsasi; Hamami, Murwani, Irmina Kris

    2016-03-01

    Glass ionomer cement (GIC) has limitation on the mechanical properties especially compressive strength. The change of compressive strength of GIC by adding oxalic acid and tartaric acid has been investigated. Oxalic acid and tartaric acid was added to the liquid components at concentrations of 0 - 15% (w/w). Powder component of GIC was made from optimum experimental powder glass SiO2-Al2O3-CaF2. GIC was characterized by compressive strength test, SEM-EDX and FTIR. The addition of tartaric acid to GIC has greater improvement than addition of oxalic acid. The addition of tartaric acid at 10 % (w/w) to GIC has greatest value of compressive strength.

  14. Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries.

    Science.gov (United States)

    Sun, Liang; Qiu, Keqiang

    2012-08-01

    Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO(2) and CoO directly as CoC(2)O(4)·2H(2)O with 1.0 M oxalate solution at 80°C and solid/liquid ratio of 50 g L(-1) for 120 min. The reaction efficiency of more than 98% of LiCoO(2) can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.

  15. Influence of Amitraz and Oxalic Acid on the Cuticle Proteolytic System of Apis mellifera L. Workers

    Directory of Open Access Journals (Sweden)

    Grzegorz Borsuk

    2012-08-01

    Full Text Available This work verifies that amitraz and oxalic acid treatment affect honeybee cuticle proteolytic enzymes (CPE. Three bee groups were monitored: oxalic acid treatment, amitraz treatment, control. Electrophoresis of hydrophilic and hydrophobic CPE was performed. Protease and protease inhibitor activities (in vitro and antifungal/antibacterial efficiencies (in vivo, were analyzed. Amitraz and oxalic acid treatment reduced hydrophobic, but did not affect hydrophilic, protein concentrations and reduced both hydrophilic and hydrophobic body surface asparagine and serine protease activities in relation to most substrates and independently of pH. The activities of natural cuticle inhibitors of acidic, neutral, and alkaline proteases were suppressed as a result of the treatments, corresponding with reduced antifungal and antibacterial activity. Electrophoretic patterns of low-, medium-, and high-molecular-weight proteases and protease inhibitors were also affected by the treatments.

  16. Influence of oxazolidines and zirconium oxalate crosslinkers on the hydrothermal, enzymatic, and thermo mechanical stability of type 1 collagen fiber

    Energy Technology Data Exchange (ETDEWEB)

    Haroun, Mahdi A. [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang (Malaysia)], E-mail: Mahdiupm@hotmail.com; Khirstova, Palmina K. [People' s Hall 11113, P.O. Box 6272, Khartoum (Sudan); Gasmelseed, Gurashi A. [Juba University, Leather Dept. P.O. Box 12327 Khartoum (Sudan); Covington, Antony D. [Leather Centre, University College Northampton, Northampton (United Kingdom)

    2009-02-20

    Stabilization of type I rat tail tendon (RTT) collagen by crosslink agent oxazolidine and zirconium oxalate was studied to understand the effect on the thermal, enzymatic and mechanical stability of collagen. The results show that both oxazolidine and zirconium oxalate imparts thermal stability to collagen, and oxazolidine exhibits a marked increase in the peak temperature and enthalpy changes when compared to both native and zirconium oxalate tanned RTT. There is a decrease in the peak temperature and the enthalpy changes of oxazolidine tanned RTT fibers after treatment with urea, suggesting the possibility of alterations in the secondary structure of collagen after tanning. Oxazolidine, which forms carbocationic intermediates species in solution, have better crosslinking with collagen as seen from viscometry studies and hence provides better enzymatic stability to collagen than zirconium, which largely forms monomeric species in solution. Zirconium does not seem to change the tensile strength of RTT fibers significantly in wet condition as well as oxazolidine.

  17. A kinetic and ESR investigation of iron(II) oxalate oxidation by hydrogen peroxide and dioxygen as a source of hydroxyl radicals

    DEFF Research Database (Denmark)

    Park, J S; Wood, P M; Davies, Michael Jonathan

    1997-01-01

    The reaction of Fe(II) oxalate with hydrogen peroxide and dioxygen was studied for oxalate concentrations up to 20 mM and pH 2-5, under which conditions mono- and bis-oxalate complexes (Fe[II](ox) and Fe[II](ox)2[2-]) and uncomplexed Fe2+ must be considered. The reaction of Fe(II) oxalate...... with hydrogen peroxide (Fe2+ + H2O2 --> Fe3+ + .OH + OH-) was monitored in continuous flow by ESR with t-butanol as a radical trap. The reaction is much faster than for uncomplexed Fe2+ and a rate constant, k = 1 x 10(4) M(-1) s(-1) is deduced for Fe(II)(ox). The reaction of Fe(II) oxalate with dioxygen...... by oxalate. Further ESR studies with DMPO as spin trap reveal that reaction of Fe(II) oxalate with hydrogen peroxide can also lead to formation of the carboxylate radical anion (CO2-), an assignment confirmed by photolysis of Fe(II) oxalate in the presence of DMPO....

  18. Calcium acetate induces calcium uptake and formation of calcium-oxalate crystals in isolated leaflets of Gleditsia triacanthos L.

    Science.gov (United States)

    Borchert, R

    1986-09-01

    During treatment of isolated, peeled leaflets of Gleditsia triacanthos with 0.5-2 mM [(45)Ca]acetate, saturation of the cell-wall free space with Ca(2+) occurred within 10 min and was followed by a period of 6-10 h during which there was no significant Ca-uptake into the protoplast, but apoplastic Ca(2+) was periodically released into the medium. Later, Ca(2+) was absorbed for 3-4 d at rates of up to 2.2 μmol Ca(2+)·h(-1)·(g FW)(-1) to final concentrations of 350 μmol Ca(2+)· (g FW)(-1). The distribution of absorbed Ca(2+) between cell wall, vacuole and Ca-oxalate crystals was determined during Ca-uptake. Wheras intact, cut leaflets deposited absorbed Ca(2+) as Ca-oxalate in the crystal cells, peeled leaflets lacking crystal cells accumulated at least 40-50 μmol·(g FW)(-1) soluble Ca(2+) before the absorbed Ca(2+) was precipitated as Ca-oxalate. These observations indicate that the mechanisms for the continuous uptake of Ca(2+), the synthesis of oxalate and the precipitation of Ca(2+) as Ca-oxalate are operational in the crystal cells of intact leaflets, but not in the mesophyll cells of peeled leaflets where they must be induced by exposure to Ca(2+). The precipitation of absorbed Ca(2+) as Ca-oxalate by the crystal cells of isolated Gleditsia leaflets illustrates the role of these cells in the excretion of surplus Ca(2+) which enters normal, attached leaves with the transpiration stream.In addition to acetate, only Ca-lactate and Ca-carbonate lead to Ca-uptake, but at rates well below those observed with Ca-acetate. Other small organic anions (citrate, glycolate, glyoxalate, malate) and inorganic anions (chloride, nitrate, sulfate) did not permit Ca-uptake. Acetate-(14)C was rapidly absorbed during Ca-uptake, but less than 20% was incorporated into Ca-oxalate; the rest remained mostly in the soluble fraction or was metabolized to CO2. Acetate, as a permeable weak acid, may enable rapid Ca-uptake by stimulating proton extrusion at the plasmalemma and by

  19. Crystal structure of bis[3-methoxy-17β-estra-1,3,5(10-trien-17-yl] oxalate

    Directory of Open Access Journals (Sweden)

    William T. A. Harrison

    2014-08-01

    Full Text Available In the title compound, C40H50O6, a symmetrical steroid oxalate diester, the dihedral angle between the CO2 planes of the oxalate linker is 61.5 (5° and the C—C bond length is 1.513 (6 Å. The steroid B, C and D rings adopt half-chair, chair and envelope conformations, respectively, in both halves of the molecule, which adopts an overall shallow V-shaped conformation. In the crystal, molecules are linked by weak C—H...O interactions, forming a three-dimensional network.

  20. Nucleation Controlled Growth of Cadmium Oxalate Crystals in Agar Gel and Their Characterization

    Directory of Open Access Journals (Sweden)

    P. V. Dalal

    2013-01-01

    Full Text Available Perfect single crystals of cadmium oxalate have been grown using the slow and controlled reaction between cadmium acetate and oxalic acid in agar gel media at ambient temperature, resulting in the formation of insoluble product Cd(COO2. Different methods for growing crystals were adopted. The optimum conditions were employed in each method by varying the concentration of gel and reactants, gel setting time, and so forth. Prismatic, transparent single crystal about 20 times larger than the crystals obtained in various other methods at the interstitial by adding impurities in the gel was obtained. The grown crystals was characterized with the help of FT-IR studies and triclinic system of crystals were supported with lattice parameters a = 8.803 A0, b = 22.352 A0, c = 5.706 A0, α = 95.74 A0, β = 90.92 A0, γ = 117.01 A0, and V = 994.69 A03, calculated from X-ray diffractogram.

  1. Raman spectroscopic analysis of the calcium oxalate producing extremotolerant lichen Circinaria gyrosa

    Science.gov (United States)

    Böttger, U.; Meessen, J.; Martinez-Frias, J.; Hübers, H.-W.; Rull, F.; Sánchez, F. J.; de la Torre, R.; de Vera, J.-P.

    2014-01-01

    In the context of astrobiological exposure and simulation experiments in the BIOMEX project, the lichen Circinaria gyrosa was investigated by Raman microspectroscopy. Owing to the symbiotic nature of lichens and their remarkable extremotolerance, C. gyrosa represents a valid model organism in recent and current astrobiological research. Biogenic compounds of C. gyrosa were studied that may serve as biomarkers in Raman assisted remote sensing missions, e.g. ExoMars. The surface as well as different internal layers of C. gyrosa have been characterized and data on the detectability and distribution of β-carotene, chitin and calcium oxalate monohydrate (whewellite) are presented in this study. Raman microspectroscopy was applied on natural samples and thin sections. Although calcium oxalates can also be formed by rare geological processes it may serve as a suitable biomarker for astrobiological investigations. In the model organism C. gyrosa, it forms extracellular crystalline deposits embedded in the intra-medullary space and its function is assumed to balance water uptake and gas exchange during the rare, moist to wet environmental periods that are physiologically favourable. This is a factor that was repeatedly demonstrated to be essential for extremotolerant lichens and other organisms. Depending on the decomposition processes of whewellite under extraterrestrial environmental conditions, it may not only serve as a biomarker of recent life, but also of past and fossilized organisms.

  2. A novel 3D framework indium phosphite-oxalate based on a pcu-type topology

    Science.gov (United States)

    Zuo, Mengmeng; Zhou, Mingdong; Hu, Dianwen; Gao, Fan; Dong, Sijie; Huang, Liangliang

    2016-05-01

    A new inorganic-organic hybrid indium phosphite-oxalate, formulated as H[In5(HPO3)6(H2PO3)2(C2O4)2]·(C4N2H11)2·H2O 1 has been hydrothermally synthesized in the presence of piperazine acting as a structure directing agent (SDA). The single crystal X-ray diffraction reveals that compound 1 shows three-dimensional open-framework with intersecting 12-ring channels along the [010] and [001] directions, which is constructed from strictly alternating double 6-ring units (D6Rs), [C2O4]2- groups and [H2PO3]- pseudo-pyramids. It is noted that the classical D6R SBU is firstly reported in main metal phosphite/phosphite-oxalate. By regarding D6R as the 6-connected nodes, the inorganic-organic hybrid framework is based on a pcu-type topology. The as-synthesized product was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), ICP-AES and elemental analyses.

  3. Cassava Pulp Hydrolysis under Microwave Irradiation with Oxalic Acid Catalyst for Ethanol Production

    Directory of Open Access Journals (Sweden)

    Euis Hermiati

    2014-07-01

    Full Text Available Microwave irradiation is an alternative method of starch hydrolysis that offers a rapid process. The aim of this research was to improve microwave-assisted hydrolysis of cassava pulp by using oxalic acid as a catalyst. Suspension of cassava pulp in 0.5% oxalic acid (1 g/20 mL was subjected to microwave irradiation at 140-230 °C for 5 minutes, with 4 minutes of pre-heating. One gram of fractured activated carbon made of coconut shell was added into a number of suspensions that were subjected to the same conditions of microwave irradiation. The soluble fraction of the hydrolysates was analyzed for its total soluble solids, malto-oligomer distribution, glucose content, pH value, and formation of brown compounds. The effects of the combined severity parameter at a substrate concentration of 5-12.5% on the glucose yield were also evaluated. The highest glucose yield (78% of dry matter was obtained after hydrolysis at 180 °C without activated carbon addition. Heating above 180 °C reduced the glucose yield and increased the pH and the formation of brown compounds. The use of activated carbon in microwave-assisted acid hydrolysis of cassava pulp reduced the glucose yield, but suppressed the formation of brown compounds. The highest glucose yield (70-80% of dry matter was attained at a severity parameter of 1.3-1.5.

  4. Magnetic properties of NiCuZn ferrites synthesized by oxalate precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Ghodake, S.A. [Department of Physics, Applied Electronics, Solapur University, Kegaon, Solapur 413 255 (India); Ghodake, U.R. [Department of Physics, Applied Electronics, Solapur University, Kegaon, Solapur 413 255 (India); Sawant, S.R. [Department of Electronics, Shivaji University, Kolhapur 416 004 (India); Suryavanshi, S.S. [Department of Physics, Applied Electronics, Solapur University, Kegaon, Solapur 413 255 (India)]. E-mail: sssuryavanshi@rediffmail.com; Bakare, P.P. [Centre for Material Characterization, National Chemical Laboratory, Pune 411008 (India)

    2006-10-15

    Ni-Cu-Zn ferrites have been synthesized by employing co-precipitation technique using oxalate precursors. X-ray diffractograms did not show impurity phases, indicating single-phase formation of the ferrites. The diffractograms of oxalate complex decomposed at 650 deg. C show that ferritization is complete up to 650 deg. C. Lattice parameter a (A) was found to decrease with the addition of Ni{sup 2+} which is attributed to ionic sizes of Ni{sup 2+} (0.69A), which replaces Cu{sup 2+} (0.72A). From the thermogravimetric studies it is observed that the experimentally observed total mass loss (%), agrees with theoretically calculated mass loss (%) indicating maintenance of requisite stoichiometry. Initial permeability ({mu}{sub i} ) shows increase when Ni{sup 2+} is added up to x=0.15 while for (x>0.15), it decreases. The increase in initial permeability ({mu}{sub i}) is attributed to monotonic increase in Ms, and K{sub 1} on addition of Ni{sup 2+}. However, the microstructure and density (porosity) also influence {mu}{sub i} variations. The decrease in {mu}{sub i} is attributable to increase of K{sub 1.} The composition with density 91.14% exhibits large {mu}{sub i} which also tends to increase with temperature up to 60 deg. C. Thus its usable range extends up to 60 deg. C. This samples has T{sub c} near to 160 deg. C.

  5. CORROSION TESTING OF CARBON STEEL IN OXALIC ACID CHEMICAL CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.; Mickalonis, J.; Subramanian, K.; Ketusky, E.

    2011-10-14

    Radioactive liquid waste has been stored in underground carbon steel tanks for nearly 60 years at the Savannah River Site. The site is currently in the process of removing the waste from these tanks in order to place it into vitrified, stable state for longer term storage. The last stage in the removal sequence is a chemical cleaning step that breaks up and dissolves metal oxide solids that cannot be easily pumped out of the tank. Oxalic acid has been selected for this purpose because it is an effective chelating agent for the solids and is not as corrosive as other acids. Electrochemical and immersion studies were conducted to investigate the corrosion behavior of carbon steel in simulated chemical cleaning environments. The effects of temperature, agitation, and the presence of sludge solids in the oxalic acid on the corrosion rate and the likelihood of hydrogen evolution were determined. The testing showed that the corrosion rates decreased significantly in the presence of the sludge solids. Corrosion rates increased with agitation, however, the changes were less noticeable.

  6. Dual roles of brushite crystals in calcium oxalate crystallization provide physicochemical mechanisms underlying renal stone formation.

    Science.gov (United States)

    Tang, R; Nancollas, G H; Giocondi, J L; Hoyer, J R; Orme, C A

    2006-07-01

    Calcium oxalate monohydrate (COM) crystals are the major mineral component of most kidney stones, and thus have an important role in chronic human disease. However, the physicochemical mechanisms leading to calcium oxalate (CaOx) stone disease are only partially defined. As spontaneous precipitation of CaOx is rare under renal conditions, an alternative pathway for CaOx crystallization seems necessary to resolve this central issue. We performed kinetic studies using the dual constant composition method to simultaneously analyze the crystallization of COM and brushite, the form of calcium phosphate that is most readily formed in the typical slightly acidic urinary milieu. These studies were supported by parallel analysis by scanning electron and atomic force microscopy. In these studies, mineralization of a thermodynamically stable phase (COM) was induced by the presence of brushite, a more readily precipitated inorganic phase. Furthermore, once formed, the COM crystals grew at the expense of brushite crystals causing the dissolution of the brushite crystals. These studies show that brushite may play crucial roles in the formation of COM crystals. The definition of these two roles for brushite thereby provides physicochemical explanations for the initiation of COM crystallization and also for the relative paucity of calcium phosphate detected in the majority of CaOx renal stones.

  7. DC resistivity of Ni-Zn ferrites prepared by oxalate precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, T.J. [Department of Physics, K.R.P. Kanya Mahavidyalaya, Islampur 415409 (India)], E-mail: pshindetj@yahoo.co.in; Gadkari, A.B. [Department of Physics, G.K.G. College, Kolhapur 416004 (India); Vasambekar, P.N. [Department of Electronics, Shivaji University, Kolhapur 416004 (India)

    2008-09-15

    Polycrystalline ferrites with general formula Ni{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by oxalate precipitation method. The samples were characterized by X-ray diffraction (XRD), IR and scanning electron microscope (SEM) techniques. All compositions show cubic Spinel structure. Lattice constant increases with increase in zinc content, obeying Vegard's law. The physical densities are about 98.14% of their X-ray density. Average crystallite size lies in the range 27.59-31.49 nm. Infrared studies show two absorption bands near about 400 cm{sup -1} and 600 cm{sup -1} for octahedral and tetrahedral sites, respectively. The resistivity of all the samples was studied. It is observed that the resistivity of nickel-zinc ferrites prepared by oxalate precipitation method is higher than that prepared by ceramic and citrate precursor method. It is attributed to greater homogeneity and smaller grain size. Activation energy in paramagnetic region is higher than that of ferrimagnetic region.

  8. Orlistat-induced oxalate nephropathy may be dose-independent and present as a late manifestation.

    Science.gov (United States)

    Dossabhoy, Neville R; McRight, Scott; Sangha, Bhupinder; Khan, Sarah; Adgeh, Cherinet

    2013-01-01

    We present the case of a 61-year-old Caucasian male veteran who had been on orlistat (120mg dosing) for four years, and had changed to the over-the-counter (OTC) form, Alli (orlistat 60mg), about three months before presentation. He had been experiencing nausea and vomiting for three weeks prior to evaluation. Laboratory studies revealed a serum creatinine of 6.2 mg/dL--his previous renal function having been normal. An ultrasound-guided renal biopsy was performed, which revealed deposition of calcium oxalate crystals in the renal tubules. Orlistat is a popular weight-loss medication. Orlistat-induced oxalate crystal nephropathy has recently been reported in the literature, resulting from the original, patented version. We report a case with the first such complication from the OTC version, Alli - which is a reduced-dose formulation. Our case report highlights that this complication can occur after several years of use of the medication and is not necessarily dose dependant.

  9. Novel approach to recover cobalt and lithium from spent lithium-ion battery using oxalic acid.

    Science.gov (United States)

    Zeng, Xianlai; Li, Jinhui; Shen, Bingyu

    2015-09-15

    With the booming of consumer electronics (CE) and electric vehicle (EV), a large number of spent lithium-ion battery (LIBs) have been generated worldwide. Resource depletion and environmental concern driven from the sustainable industry of CE and EV have motivated spent LIBs should be recovered urgently. However, the conventional process combined with leaching, precipitating, and filtering was quite complicated to recover cobalt and lithium from spent LIBs. In this work, we developed a novel recovery process, only combined with oxalic acid leaching and filtering. When the optimal parameters for leaching process is controlled at 150 min retention time, 95 °C heating temperature, 15 g L(-1) solid-liquid ratio, and 400 rpm rotation rate, the recovery rate of lithium and cobalt from spent LIBs can reach about 98% and 97%, respectively. Additionally, we also tentatively discovered the leaching mechanism of lithium cobalt oxide (LiCoO2) using oxalic acid, and the leaching order of the sampling LiCoO2 of spent LIBs. All the obtained results can contribute to a short-cut and high-efficiency process of spent LIBs recycling toward a sound closed-loop cycle. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. High-performing mesoporous iron oxalate anodes for lithium-ion batteries.

    Science.gov (United States)

    Ang, Wei An; Gupta, Nutan; Prasanth, Raghavan; Madhavi, Srinivasan

    2012-12-01

    Mesoporous iron oxalate (FeC(2)O(4)) with two distinct morphologies, i.e., cocoon and rod, has been synthesized via a simple, scalable chimie douce precipitation method. The solvent plays a key role in determining the morphology and microstructure of iron oxalate, which are studied by field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Crystallographic characterization of the materials has been carried out by X-ray diffraction and confirmed phase-pure FeC(2)O(4)·2H(2)O formation. The critical dehydration process of FeC(2)O(4)·2H(2)O resulted in anhydrous FeC(2)O(4), and its thermal properties are studied by thermogravimetric analysis. The electrochemical properties of anhydrous FeC(2)O(4) in Li/FeC(2)O(4) cells are evaluated by cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. The studies showed that the initial discharge capacities of anhydrous FeC(2)O(4) cocoons and rods are 1288 and 1326 mA h g(-1), respectively, at 1C rate. Anhydrous FeC(2)O(4) cocoons exhibited stable capacity even at high C rates (11C). The electrochemical performance of anhydrous FeC(2)O(4) is found to be greatly influenced by the number of accessible reaction sites, morphology, and size effects.

  11. Calcium Oxalate Stone Agglomeration Inhibition [tm] Reflects Renal Stone-Forming Activity.

    Science.gov (United States)

    Lindberg, J S; Cole, F E; Romani, W; Husserl, F E; Fuselier, H A; Kok, D J; Erwin, D T

    2000-04-01

    Louisiana and other Gulf South states comprise a "Stone Belt" where calcium oxalate stone formers (CaOx SFs) are found at a high rate of approximately 5%. In these patients, the agglomeration of small stone crystals, which are visible in nearly all morning urine collections, forms stones that can become trapped in the renal parenchyma and the renal pelvis. Without therapy, about half of CaOx SFs repeatedly form kidney stones, which can cause excruciating pain that can be relieved by passage, fragmentation (lithotripsy), or surgical removal. The absence of stones in "normal" patients suggests that there are stone inhibitors in "normal" urines.At the Ochsner Renal Stone Clinic, 24-hour urine samples are collected by the patient and sent to the Ochsner Renal Stone Research Program where calcium oxalate stone agglomeration inhibition [tm] measurements are performed. Urine from healthy subjects and inactive stone formers has demonstrated strongly inhibited stone growth [tm] in contrast to urine from recurrent CaOx SFs. [tm] data from 1500 visits of 700 kidney stone patients have been used to evaluate the risk of recurrence in Ochsner's CaOx SF patients. These data have also been used to demonstrate the interactive roles of certain identified urinary stone-growth inhibitors, citrate and Tamm-Horsfall protein (THP), which can be manipulated with medication to diminish recurrent stone formation. Our goal is to offer patients both financial and pain relief by reducing their stones with optimized medication, using medical management to avoid costly treatments.

  12. Blumea Balsamifera (Sambong Tea as a Therapeutic Drink for Calcium Oxalate Stones

    Directory of Open Access Journals (Sweden)

    Montealegre Charlimagne M.

    2016-01-01

    Full Text Available Calcium oxalate stones are among the most prevalent type of kidney stones. Methods of treatment range from surgical removal, shockwave lithotripsy, medical and natural treatment. In the Philippines, consuming tea preparation of Blumea balsamifera is believed to aid in the treatment of kidney stones. The effect of Blumea balsamifera tea in the nucleation of calcium oxalate crystals was studied at 0, 0.5 and 1.0 mg tea preparation per mL of the crystallization solution by UV-Vis spectrophotomery. Induction time decreased with increasing concentration of Blumea balsamifera tea. Further analysis showed that this decrease in induction time is due to a decrease in surface free energy from 20.95 mJ/m2 to 19.48 mJ/m2 and 17.22 mJ/m2 at 0.5 and 1.0 mg/mL, respectively. This decrease in induction time correspond to an increased nucleation rate thus, a large number of smaller crystals are formed. This explains the therapeutic benefits of consuming Blumea balsamifera tea as stone formers would form smaller stones that are easier to eliminate by urination.

  13. Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

    Science.gov (United States)

    Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming; An, Ran; Yang, Meng-Lin; Xue, Ganglin

    2017-01-01

    Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox)0.5(H2O)]n·2n(H2O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H2sfpip)(ox)(H2O)4]n·2n(H2O) (Ln=Nd (8) Sm (9)), [H2ox=oxalic acid, H3sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H3sfpip resulted in two types of structures. Compounds 1-7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox2- anions as linkers to bridge the adjacent layers. Compounds 8-9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1-7 to 8-9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1-9 were also investigated.

  14. Renal Calcium Oxalate Deposits Induce a Pro-Atherosclerotic and Pro-Osteoporotic Response in Mice.

    Science.gov (United States)

    Kusumi, Kirsten; Barr-Beare, Evan; Saxena, Vijay; Safedi, Fayez; Schwaderer, Andrew

    2017-09-01

    Urinary stone disease (USD) is increasing in adult and pediatric populations. Adult and pediatric studies have demonstrated decreased bone mineral density and increased fracture rates. USD has also been independently linked to increased rates of myocardial infarction and cerebral vascular accidents. Although USD is a multisystem disorder involving the kidneys, bone, and vasculature, the molecular mechanisms linking these three organs remain unknown. Calcium oxalate nephropathy was induced in C57BL/6J mice with intra-peritoneal (ip) injection of sodium glyoxolate. Half of each kidney underwent Pizzalato staining and half was snap frozen for RNA extraction. RT(2) Profiler Mouse Atherosclerosis, Osteoporosis, and Calcium Signaling PCR Arrays (Qiagen) were performed. Only results that passed quality checks in PCR array reproducibility and genomic DNA contamination were included. Genes had to show at least fourfold differential expression and P 10-fold increase. All 10 have P ≤ 0.003. The calcium signaling array showed significant fourfold upregulation of 10 genes, four of which were ≥10-fold. All 10 have P ≤ 0.03. We have demonstrated that calcium oxalate nephropathy can induce upregulation of atherosclerotic, metabolic bone, and calcium homeostasis genes in a murine model. This may be and initial step in identifying the molecular mechanisms linking stone, bone, and cardiovascular disease. J. Cell. Biochem. 118: 2744-2751, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  15. In vitro effects of metal oxide nanoparticles on barley oxalate oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Nidhi [M. D. University, Department of Biochemistry (India); Hooda, Vinita [M. D. University, Department of Botany (India); Pundir, C. S., E-mail: pundircs@rediffmail.com [M. D. University, Department of Biochemistry (India)

    2013-03-15

    Barley oxalate oxidase (OxO), a manganese-containing protein, is largely employed for determination of oxalate in various biologic materials. The present report describes in vitro effects of nanoparticles (NPs) of three metal oxides, i.e., zinc oxide (ZnO), copper oxide (CuO), and manganese oxide (MnO{sub 2}), on the activity and stability of OxO purified from barley roots. The transmission electron microscopy and X-ray diffraction studies of these NPs revealed their very fine crystalline structure with the dimeter in the range 30-70, 50-60, and 20-60 nm for ZnO NPs, CuO NPs, and MnO{sub 2} NPs, respectively. The addition of suspension of these three NPs into assay mixture of enzyme individually, led to the adsorption of OxO over their surface, as confirmed by Fourier transform infrared spectra and UV-Vis spectroscopic studies. Compared to free enzyme, MnO{sub 2} NPs-bound enzyme showed improved activity (35 % stimulation at 2.5 mg/ml concentration), while ZnO NPs- and CuO NPs-bound enzyme had no substantial improvement. The kinetic properties of individually NPs-bound enzyme were studied and compared with those of free enzyme. The MnO{sub 2} NPs-bound enzyme also showed marked improvement in its storage and thermal stability compared to free enzyme.

  16. Mechanism of electron transfer reaction of ternary dipicolinatochromium(III) complex involving oxalate as secondary ligand

    Indian Academy of Sciences (India)

    Hassan Amroun Ewais; Iqbal Mohamed Ibrhium Ismail

    2013-09-01

    Mechanism of electron transfer reaction of ternary Mechanism of the oxidation of [CrIII(DPA)(OX)(H2O)]− (DPA = dipicolinate and OX = oxalate) by periodate in aqueous acidic medium has been studied spectrophotometrically over the pH range of 4.45-5.57 at different temperatures. The reaction is first order with respect to both [IO$^{−}_{4}$] and the complex concentration, and it obeys the following rate law: $$d[{\\text Cr}^{\\text{VI}}]/dt = k_6K_4K_6[{\\text IO}^−_4][{\\text{Cr}}^{\\text{III}}]_{\\text{T}}/\\{([H^+] + K_4) + (K_5[H+] + K_6K_4)[{\\text{IO}}^{−}_{4}]\\}.$$ The rate of the reaction increases with increasing pH due to the deprotonation equilibria of the complex. The experimental rate law is consistent with a mechanism in which the deprotonated form [CrIII(DPA)(OX)(OH)]2− is more reactive than the conjugated acid. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO$^{−}_{4}$ to chromium(III). Thermodynamic activation parameters were calculated using the transition state theory equation.dipicolinatochromium(III) complex involving oxalate as secondary ligand

  17. Genomic evaluation of oxalate-degrading transgenic soybean in response to Sclerotinia sclerotiorum infection.

    Science.gov (United States)

    Calla, Bernarda; Blahut-Beatty, Laureen; Koziol, Lisa; Zhang, Yunfang; Neece, David J; Carbajulca, Doris; Garcia, Alexandre; Simmonds, Daina H; Clough, Steven J

    2014-08-01

    Oxalate oxidases (OxO) catalyse the degradation of oxalic acid (OA). Highly resistant transgenic soybean carrying an OxO gene and its susceptible parent soybean line, AC Colibri, were tested for genome-wide gene expression in response to the necrotrophic, OA-producing pathogen Sclerotinia sclerotiorum using soybean cDNA microarrays. The genes with changed expression at statistically significant levels (overall F-test P-value cut-off of 0.0001) were classified into functional categories and pathways, and were analysed to evaluate the differences in transcriptome profiles. Although many genes and pathways were found to be similarly activated or repressed in both genotypes after inoculation with S. sclerotiorum, the OxO genotype displayed a measurably faster induction of basal defence responses, as observed by the differential changes in defence-related and secondary metabolite genes compared with its susceptible parent AC Colibri. In addition, the experiment presented provides data on several other transcripts that support the hypothesis that S. sclerotiorum at least partially elicits the hypersensitive response, induces lignin synthesis (cinnamoyl CoA reductase) and elicits as yet unstudied signalling pathways (G-protein-coupled receptor and related). Of the nine genes showing the most extreme opposite directions of expression between genotypes, eight were related to photosynthesis and/or oxidation, highlighting the importance of redox in the control of this pathogen.

  18. Does aridity influence the morphology, distribution and accumulation of calcium oxalate crystals in Acacia (Leguminosae: Mimosoideae)?

    Science.gov (United States)

    Brown, Sharon L; Warwick, Nigel W M; Prychid, Christina J

    2013-12-01

    Calcium oxalate (CaOx) crystals are a common natural feature of many plant families, including the Leguminosae. The functional role of crystals and the mechanisms that underlie their deposition remain largely unresolved. In several species, the seasonal deposition of crystals has been observed. To gain insight into the effects of rainfall on crystal formation, the morphology, distribution and accumulation of calcium oxalate crystals in phyllodes of the leguminous Acacia sect. Juliflorae (Benth.) C. Moore & Betche from four climate zones along an aridity gradient, was investigated. The shapes of crystals, which include rare Rosanoffian morphologies, were constant between species from different climate zones, implying that morphology was not affected by rainfall. The distribution and accumulation of CaOx crystals, however, did appear to be climate-related. Distribution was primarily governed by vein density, an architectural trait which has evolved in higher plants in response to increasing aridity. Furthermore, crystals were more abundant in acacias from low rainfall areas, and in phyllodes containing high concentrations of calcium, suggesting that both aridity and soil calcium levels play important roles in the precipitation of CaOx. As crystal formation appears to be calcium-induced, we propose that CaOx crystals in Acacia most likely function in bulk calcium regulation.

  19. Kidney injury molecule-1 is up-regulated in renal epithelial cells in response to oxalate in vitro and in renal tissues in response to hyperoxaluria in vivo.

    Directory of Open Access Journals (Sweden)

    Lakshmipathi Khandrika

    Full Text Available Oxalate is a metabolic end product excreted by the kidney. Mild increases in urinary oxalate are most commonly associated with Nephrolithiasis. Chronically high levels of urinary oxalate, as seen in patients with primary hyperoxaluria, are driving factor for recurrent renal stones, and ultimately lead to renal failure, calcification of soft tissue and premature death. In previous studies others and we have demonstrated that high levels of oxalate promote injury of renal epithelial cells. However, methods to monitor oxalate induced renal injury are limited. In the present study we evaluated changes in expression of Kidney Injury Molecule-1 (KIM-1 in response to oxalate in human renal cells (HK2 cells in culture and in renal tissue and urine samples in hyperoxaluric animals which mimic in vitro and in vivo models of hyper-oxaluria. Results presented, herein demonstrate that oxalate exposure resulted in increased expression of KIM-1 m RNA as well as protein in HK2 cells. These effects were rapid and concentration dependent. Using in vivo models of hyperoxaluria we observed elevated expression of KIM-1 in renal tissues of hyperoxaluric rats as compared to normal controls. The increase in KIM-1 was both at protein and mRNA level, suggesting transcriptional activation of KIM-1 in response to oxalate exposure. Interestingly, in addition to increased KIM-1 expression, we observed increased levels of the ectodomain of KIM-1 in urine collected from hyperoxaluric rats. To the best of our knowledge our studies are the first direct demonstration of regulation of KIM-1 in response to oxalate exposure in renal epithelial cells in vitro and in vivo. Our results suggest that detection of KIM-1 over-expression and measurement of the ectodomain of KIM-1 in urine may hold promise as a marker to monitor oxalate nephrotoxicity in hyperoxaluria.

  20. Ion-exchange behavior of Hf, Ta, and W as homologs of elements 104, 105, and 106 in oxalic-acid and oxalic-acid-HCl solutions

    Energy Technology Data Exchange (ETDEWEB)

    Szeglowski, Z.; Guseva, L.I.; Din-Ti-Lien, Domanov, V.P.; Constantinescu, M.; Constantinescu, O.; Tikhomirova, G.S.; Hussonnois, M.

    1995-01-01

    Distribution coefficients are determined for Zr, Hf, Nb, Ta, Cm, Cf, and Lu on ion exchangers in H{sub 2}C{sub 2}O{sub 4} and H{sub 2}C{sub 2}O{sub 4} + HCl solutions as a function of the solution concentrations and ion-exchanger type. Optimal conditions are found for separating Group IV-VIB elements from trivalent transplutonium elements and rare earths on cation exchangers and anion exchangers in H{sub 2}C{sub 2}O{sub 4}-HCl solutions with high separation coefficients (>10{sup 4}-10{sup 5}). Model experiments are performed on the isolation of short-lived isotopes of Hf and W, which were produced by irradiation of natural Gd and {sup 144}Sm with {sup 18}O and {sup 24}Mg, respectively, in the U-400 cyclotron of the Flerov Laboratory of Nuclear Reactions at the Joint Institute of Nuclear Research. The ability to use solutions of oxalic acid to isolate the transactinide elements (104, 105, 106) and to identify them from their daughters is demonstrated.

  1. Sources and atmospheric processes impacting oxalate at a suburban coastal site in Hong Kong: Insights inferred from 1 year hourly measurements

    Science.gov (United States)

    Zhou, Yang; Huang, Xiaohui Hilda; Bian, Qijing; Griffith, Stephen M.; Louie, Peter K. K.; Yu, Jian Zhen

    2015-09-01

    Oxalic acid is one of the most abundant dicarboxylic acids in the atmosphere, receiving a great deal of attention due to its potential influence on cloud condensation nucleus activities. In this work, we report 10 months of hourly oxalate measurements in particulate matter of less than 2.5 µm in aerodynamic diameter (PM2.5) by a Monitor for Aerosols and Gases in ambient Air at a suburban coastal site in Hong Kong from April 2012 to February 2013. A total of more than 6000 sets of oxalate and inorganic ion data were obtained. The mean (±SD) oxalate concentration was 0.34 (±0.18) µg m-3, accounting for 2.8% of the total ion mass and 1.5% of the PM2.5 mass. Seasonal variation showed higher concentrations in fall and winter (0.54 and 0.36 µg m-3, respectively) and lower concentrations in spring and summer (~0.26 µg m-3). Different from the inorganic ions, a shallow dip in the oxalate concentration consistently occurred in the morning after sunrise (around 9:00 A.M.) throughout all seasons. Our analysis suggests that this was likely due to photolysis of oxalate-Fe (III) complex under sunlight. In summer, a small daytime peak was discernable for oxalate and nitrate. This characteristic, together with a more evident diurnal variation of O3, indicates comparatively more active photochemical oxidation in summer than other seasons. High correlations were observed between oxalate and non-sea-salt SO42- (NSS) (R2 = 0.63) and Ox (O3 + NO2) (R2 = 0.48), indicating significant commonality in their secondary formation. Positive matrix factorization analysis of oxalate and other real-time gas and particle-phase component data estimates that secondary formation processes, including secondary gas or aqueous oxidation processes (49%), oxidation processes of biomass burning emissions (37%), accounted for the majority of PM2.5 oxalate. A backward trajectories cluster analysis found that higher oxalate/NSS ratios were associated with low pollution samples under the influence of

  2. Synthesis of water-dispersible silver nanoparticles by thermal decomposition of water-soluble silver oxalate precursors.

    Science.gov (United States)

    Togashi, Takanari; Saito, Kota; Matsuda, Yukiko; Sato, Ibuki; Kon, Hiroki; Uruma, Keirei; Ishizaki, Manabu; Kanaizuka, Katsuhiko; Sakamoto, Masatomi; Ohya, Norimasa; Kurihara, Masato

    2014-08-01

    Silver oxalate, one of the coordination polymer crystals, is a promising synthetic precursor for transformation into Ag nanoparticles without any reducing chemicals via thermal decomposition of the oxalate ions. However, its insoluble nature in solvents has been a great disadvantage, especially for systematic control of crystal growth of the Ag nanoparticles, while such control of inorganic nanoparticles has been generally performed using soluble precursors in homogeneous solutions. In this paper, we document our discovery of water-soluble species from the reaction between the insoluble silver oxalate and N,N-dimethyl-1,3-diaminopropane. The water-soluble species underwent low-temperature thermal decomposition of the oxalate ions at 30 °C with evolution of CO2 to reduce Ag+ to Ag0. Water-dispersible Ag nanoparticles have been successfully synthesized from the water-soluble species in the presence of gelatin via similar thermal decomposition at 100 °C. The gelatin-protected and water-dispersible Ag nanoparticles with a mean diameter of 25.1 nm appeared. In addition, antibacterial activity of the prepared water-dispersible Ag nanoparticles has been preliminarily investigated.

  3. Studying inhibition of calcium oxalate stone formation: an in vitro approach for screening hydrogen sulfide and its metabolites

    Directory of Open Access Journals (Sweden)

    S. Vaitheeswari

    2015-06-01

    Full Text Available ABSTRACTPurpose:Calcium oxalate urolithiasis is one of the most common urinary tract diseases and is of high prevalence. The present study proposes to evaluate the antilithiatic property of hydrogen sulfide and its metabolites like thiosulfate & sulfate in an in vitro model.Materials and Methods:The antilithiatic activity of sodium hydrogen sulfide (NaSH, sodium thiosulfate (Na2S2O3 and sodium sulfate (Na2SO4 on the kinetics of calcium oxalate crystal formation was investigated both in physiological buffer and in urine from normal and recurrent stone forming volunteers. The stones were characterized by optical and spectroscopic techniques.Results:The stones were characterized to be monoclinic, prismatic and bipyramidal habit which is of calcium monohydrate and dihydrate nature. The FTIR displayed fingerprint corresponding to calcium oxalate in the control while in NaSH treated, S=O vibrations were visible in the spectrum. The order of percentage inhibition was NaSH>Na2S2O3>Na2SO4.Conclusion:Our study indicates that sodium hydrogen sulfide and its metabolite thiosulfate are inhibitors of calcium oxalate stone agglomeration which makes them unstable both in physiological buffer and in urine. This effect is attributed to pH changes and complexing of calcium by S2O32-and SO42- moiety produced by the test compounds.

  4. Renal tubular injury induced by ischemia promotes the formation of calcium oxalate crystals in rats with hyperoxaluria.

    Science.gov (United States)

    Cao, Yanwei; Liu, Wanpeng; Hui, Limei; Zhao, Jianjun; Yang, Xuecheng; Wang, Yonghua; Niu, Haitao

    2016-10-01

    Hyperoxaluria and cell injury are key factors in urolithiasis. Oxalate metabolism may be altered by renal dysfunction and therefore, impact the deposition of calcium oxalate (CaOx) crystals. We investigated the relationship of renal function, oxalate metabolism and CaOx crystal deposition in renal ischemia. One hundred male Sprague-Dawley rats were randomly divided into four groups. Hyperoxaluria model (Group A and B) was established by feeding rats with 0.75 % ethylene glycol (EG). The left renal pedicle was clamped for 30 min to establish renal ischemia Groups (B and C), while Groups A and D underwent sham operation. Then, serum and urine oxalate (Ox), creatinine (Cr) and urea nitrogen (UN) levels were evaluated by liquid chromatography mass spectrometry (LCMS) and ion mass spectrum (IMS) at days 0, 2, 4, 7, and 14. CaOx crystallization was assessed by transmission electron microscope (TEM). A temporal and significant increase of serum Cr and UN levels was observed in Groups B and C compared to values obtained for Groups A and D (P renal tissue. Our results indicated that renal tubular injury induced by renal ischemia might not affect Ox levels but could promote CaOx crystal retention under hyperoxaluria.

  5. Screening of indigenous oxalate degrading lactic acid bacteria from human faeces and South Indian fermented foods: assessment of probiotic potential.

    Science.gov (United States)

    Gomathi, Sivasamy; Sasikumar, Ponnusamy; Anbazhagan, Kolandaswamy; Sasikumar, Sundaresan; Kavitha, Murugan; Selvi, M S; Selvam, Govindan Sadasivam

    2014-01-01

    Lactic acid bacteria (LAB) have the potential to degrade intestinal oxalate and this is increasingly being studied as a promising probiotic solution to manage kidney stone disease. In this study, oxalate degrading LAB were isolated from human faeces and south Indian fermented foods, subsequently assessed for potential probiotic property in vitro and in vivo. Based on preliminary characteristics, 251 out of 673 bacterial isolates were identified as LAB. A total of 17 strains were found to degrade oxalate significantly between 40.38% and 62.90% and were subjected to acid and bile tolerance test. Among them, nine strains exhibited considerable tolerance up to pH 3.0 and at 0.3% bile. These were identified as Lactobacillus fermentum and Lactobacillus salivarius using 16S rDNA sequencing. Three strains, Lactobacillus fermentum TY5, Lactobacillus fermentum AB1, and Lactobacillus salivarius AB11, exhibited good adhesion to HT-29 cells and strong antimicrobial activity. They also conferred resistance to kanamycin, rifampicin, and ampicillin, but were sensitive to chloramphenicol and erythromycin. The faecal recovery rate of these strains was observed as 15.16% (TY5), 6.71% (AB1), and 9.3% (AB11) which indicates the colonization ability. In conclusion, three efficient oxalate degrading LAB were identified and their safety assessments suggest that they may serve as good probiotic candidates for preventing hyperoxaluria.

  6. Large magnetocaloric effect in a dense and stable inorganic-organic hybrid cobridged by in situ generated sulfate and oxalate.

    Science.gov (United States)

    Han, Song-De; Miao, Xiao-Hong; Liu, Sui-Jun; Bu, Xian-He

    2014-11-01

    A dense and stable inorganic-organic hybrid with distorted cubic [Gd4O4] units as building blocks bridged by in situ generated sulfate and oxalate was synthesized. Magnetic measurements indicate that the title complex features a -ΔS(m)(max)=51.49 J kg(-1) K(-1), which is among the highest values reported so far.

  7. Screening of Indigenous Oxalate Degrading Lactic Acid Bacteria from Human Faeces and South Indian Fermented Foods: Assessment of Probiotic Potential

    Directory of Open Access Journals (Sweden)

    Sivasamy Gomathi

    2014-01-01

    Full Text Available Lactic acid bacteria (LAB have the potential to degrade intestinal oxalate and this is increasingly being studied as a promising probiotic solution to manage kidney stone disease. In this study, oxalate degrading LAB were isolated from human faeces and south Indian fermented foods, subsequently assessed for potential probiotic property in vitro and in vivo. Based on preliminary characteristics, 251 out of 673 bacterial isolates were identified as LAB. A total of 17 strains were found to degrade oxalate significantly between 40.38% and 62.90% and were subjected to acid and bile tolerance test. Among them, nine strains exhibited considerable tolerance up to pH 3.0 and at 0.3% bile. These were identified as Lactobacillus fermentum and Lactobacillus salivarius using 16S rDNA sequencing. Three strains, Lactobacillus fermentum TY5, Lactobacillus fermentum AB1, and Lactobacillus salivarius AB11, exhibited good adhesion to HT-29 cells and strong antimicrobial activity. They also conferred resistance to kanamycin, rifampicin, and ampicillin, but were sensitive to chloramphenicol and erythromycin. The faecal recovery rate of these strains was observed as 15.16% (TY5, 6.71% (AB1, and 9.3% (AB11 which indicates the colonization ability. In conclusion, three efficient oxalate degrading LAB were identified and their safety assessments suggest that they may serve as good probiotic candidates for preventing hyperoxaluria.

  8. An Efficient Method for Synthesis of N-tert-Butyl Amides Using Oxalic Acid Dihydrate in Solvent-Free Condition

    Directory of Open Access Journals (Sweden)

    Masoud Mokhtary

    2014-01-01

    Full Text Available An efficient method for the synthesis of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate or tert-butanol is described using oxalic acid dihydrate in solvent-free condition. The result showed that tert-butyl acetate served as a relatively better source of tert-butyl carbocation than tert-butanol.

  9. Queen survival and oxalic acid residues in sugar stores after summer application against Varroa destructor in honey bees (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Donders, J.N.L.C.; Stratum, van P.; Blacquière, T.; Dooremalen, van C.

    2012-01-01

    Methods using oxalic acid (OA) to control Varroa destructor in honey bee (Apis mellifera) colonies are widely applied. In this study, the effects of an OA spray application in early summer on the survival of young and old queens, and on OA residues in sugar stores were investigated. A questionnaire

  10. In vitro effect of hydro alcoholic extract of Adiantum capillus-veneris Linn. on calcium oxalate crystallization

    Directory of Open Access Journals (Sweden)

    Ajij Ahmed

    2013-01-01

    Full Text Available Background: Adiantum capillus-veneris Linn. is widely used in the management of urolithiasis in Unani system of medicine. Aim: To evaluate the effect of the hydro alcoholic extract of A. capillus-veneris Linn. on calcium oxalate crystallisation by in vitro study. Materials and Methods: The study includes crystallization, nucleation and aggregation assay. Crystallization was induced by addition of 50 μl of 0.1 M sodium oxalate in whole urine in the absence and the presence of extract at different concentrations (0.50 mg, 0.75 mg and 1 mg. The nucleation and aggregation rates were followed at 620 nm after mixing calcium chloride and sodium oxalate solution and in a buffered solution containing calcium oxalate monohydrate crystals, respectively. The rate was evaluated by comparing the slope of turbidity in the presence of extract with that of control using the spectrophotometer. Crystals in the urine were also analysed by light microscopy. Results and Conclusion: Extract of the test drug inhibited the crystallization in solution; less and smaller particles were observed in the presence of extract. These results were further confirmed in the nucleation assay, though the rate of nucleation was not inhibited but number of crystals was found to be decreased. The test drug also inhibited crystal aggregation. It can be concluded therefore, that the test drug possesses significant antilithiasic activity.

  11. Luminescent and morphological study of Sr{sub 2}CeO{sub 4} blue phosphor prepared from oxalate precursors

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Jefferson L., E-mail: jeffersonferrari@gmail.co [Instituto de Quimica, Unesp Univ Estadual Paulista, P.O. Box 355, 14800-970 Araraquara, SP (Brazil); Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, SP (Brazil); Pires, Ana M. [Depto. de Fisica, Quimica e Biologia, Faculdade Ciencias e Tecnologia, Unesp Univ Estadual Paulista. P.O. Box 467, Presidente Prudente, SP 19060-900 (Brazil); Serra, Osvaldo A. [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, SP (Brazil); Davolos, Marian R. [Instituto de Quimica, Unesp Univ Estadual Paulista, P.O. Box 355, 14800-970 Araraquara, SP (Brazil)

    2011-01-15

    Luminescent and morphological studies of Sr{sub 2}CeO{sub 4} blue phosphor prepared from cerium-doped strontium oxalate precursor are reported. Powder samples were prepared from 5 and 25 mol% Ce{sup 3+}-doped strontium oxalate as well as from a mechanical mixture of strontium oxalate and cerium oxalate at a 4:1 ratio, respectively. All the samples were characterized by XRD, IR, PLS, and SEM. The luminescent and structural properties of the Sr{sub 2}CeO{sub 4} material are little affected by the SrCO{sub 3} remaining from precursors. The Sr{sub 2}CeO{sub 4} material consists in one-dimensional chains of edge-sharing CeO{sub 6} octahedra that are linked together by Sr{sup 2+} ions. The carbonate ion might be associated with oxygen ions of the linear chain, and also with the oxygen atoms located in the equatorial position, which consequently affects the charge transfer bands between O{sup 2-} and Ce{sup 4+}. As observed by SEM, the morphological changes are related to each kind of precursor and thermal treatment, along with irregular powder particles within the size range 0.5-2 {mu}m.

  12. High-sensitivity microchip electrophoresis determination of inorganic anions and oxalate in atmospheric aerosols with adjustable selectivity and conductivity detection.

    Science.gov (United States)

    Noblitt, Scott D; Schwandner, Florian M; Hering, Susanne V; Collett, Jeffrey L; Henry, Charles S

    2009-02-27

    A sensitive and selective separation of common anionic constituents of atmospheric aerosols, sulfate, nitrate, chloride, and oxalate, is presented using microchip electrophoresis. The optimized separation is achieved in under 1 min and at low background electrolyte ionic strength (2.9 mM) by combining a metal-binding electrolyte anion (17 mM picolinic acid), a sulfate-binding electrolyte cation (19 mM HEPBS), a zwitterionic surfactant with affinity towards weakly solvated anions (19 mM N-tetradecyl,N,N-dimethyl-3-ammonio-1-propansulfonate), and operation in counter-electroosmotic flow (EOF) mode. The separation is performed at pH 4.7, permitting pH manipulation of oxalate's mobility. The majority of low-concentration organic acids are not observed at these conditions, allowing for rapid subsequent injections without the presence of interfering peaks. Because the mobilities of sulfate, nitrate, and oxalate are independently controlled, other minor constituents of aerosols can be analyzed, including nitrite, fluoride, and formate if desired using similar separation conditions. Contact conductivity detection is utilized, and the limit of detection for oxalate (S/N=3) is 180 nM without stacking. Sensitivity can be increased with field-amplified sample stacking by injecting from dilute electrolyte with a detection limit of 19 nM achieved. The high-sensitivity, counter-EOF operation, and short analysis time make this separation well-suited to continuous online monitoring of aerosol composition.

  13. Extraction and estimation of the quantity of calcium oxalate crystals in the foliage of conifer and hardwood trees

    Science.gov (United States)

    Rakesh Minocha; Bradley Chamberlain; Stephanie Long; Swathi A. Turlapati; Gloria. Quigley

    2015-01-01

    The main goal of this study was to develop a method for the extraction and indirect estimation of the quantity of calcium oxalate (CaOx) in the foliage of trees. Foliar tissue was collected from a single tree of each species (five conifers and five hardwoods) for comparison of extractions in different solvents using 10 replicates per species from the same pool of...

  14. Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce

    Science.gov (United States)

    Kevin T. Smith; Walter C. Shortle; Jon H. Connolly; Rakesh Minocha; Jody Jellison

    2009-01-01

    Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of...

  15. Physical characteristics of calcium oxalate crystals as determinants in structural defense against chewing insects in Medicago truncatula

    Science.gov (United States)

    In addition to the numerous chemical defenses that plants employ to fend off insect herbivores, simple structural components can also play important roles in effective protection. Our investigations have shown that plant crystals of calcium oxalate can function in insect defense. The isolation of ca...

  16. Medicago truncatula-derived calcium oxalate crystals have a negative impact on chewing insect performance via their physical properties

    Science.gov (United States)

    Plant structural traits often act as defenses against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in Medicago truncatula Gaertn. (Fabaceae) leaves have previously been shown to be effective deterrents of lepidopteran insect feedi...

  17. Queen survival and oxalic acid residues in sugar stores after summer application against Varroa destructor in honey bees (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Donders, J.N.L.C.; Stratum, van P.; Blacquière, T.; Dooremalen, van C.

    2012-01-01

    Methods using oxalic acid (OA) to control Varroa destructor in honey bee (Apis mellifera) colonies are widely applied. In this study, the effects of an OA spray application in early summer on the survival of young and old queens, and on OA residues in sugar stores were investigated. A questionnaire

  18. Evaluation of ferric oxalate as an agent for use during surgery to prevent post-operative root hypersensitivity.

    Science.gov (United States)

    Wang, H L; Yeh, C T; Smith, F; Burgett, F G; Richards, P; Shyr, Y; O'Neal, R

    1993-11-01

    The aim of this study was to evaluate the effectiveness of a 6% ferric oxalate solution applied during periodontal surgery to prevent post-operative tooth hypersensitivity. Twenty-five adult patients with similar bilateral periodontal defects participated in this study. Data were collected at baseline (1 week prior to surgery) and 1, 2, 4, and 6 weeks following surgery. Sensitivity level was determined using the visual analog scale (VAS) with the following stimuli: 1) mechanical stimulation with a No. 23 dental explorer; 2) water at 50 degrees C; 3) ice; and 4) electric pulp tester (EPT). Teeth were randomly assigned to either test (6% ferric oxalate in 0.9% saline) or control (0.9% saline) groups. Solutions were applied to the exposed root surfaces for 1 minute during surgery. Data were analyzed by repeated measures ANOVA, paired t-test, and Pearson's correlation test. Results from this study demonstrated statistically significant reduction in the responses to thermal stimuli, especially cold, between groups treated with ferric oxalate as compared to those treated with saline. For the cold test the difference increased with time from baseline to 6 weeks. Statistically significant (P surgery. There were no differences at any time period between the test and control groups when tactile or EPT techniques were used. In addition, there was no correlation between sensitivity and other clinical parameters. It was concluded from this study that 6% ferric oxalate was effective in reducing post-surgical cold sensitivity when applied during periodontal surgical procedures.

  19. Synthesis of Copper Oxalate Nanorods by a Simple One-step Solid-state Chemical Reaction Method

    Institute of Scientific and Technical Information of China (English)

    CAO Ya-li; JIA Dian-zeng; LIU Lang; XIAO Ding-quan; XIN Xin-quan

    2005-01-01

    Copper oxalate nanorods were successfully prepared by means of a simple one-step solid-state reaction method with the assistance of a suitable surfactant, polyethylene glycol 400. The product with uniform rodlike morphology was characterized by XRD, TEM and SEM. The formational mechanism of the rod-like structure was also preliminary discussed.

  20. Dietary and animal-related factors associated with the rate of urinary oxalate and calcium excretion in dogs and cats

    NARCIS (Netherlands)

    Dijcker, J. C.; Hagen-Plantinga, E. A.; Everts, H.; Bosch, G.; Kema, I. P.; Hendriks, W. H.

    2012-01-01

    This paper reports the results of a cohort study and randomised clinical trial (RCT) in cross-over design. In the cohort study, the range of urinary oxalate (Uox) and calcium (Uca) excretion was determined within a sample of the Dutch population of dogs and cats, and dietary and animal-related

  1. Dietary and animal-related factors associated with the rate of urinary oxalate and calcium excretion in dogs and cats

    NARCIS (Netherlands)

    Dijcker, J.C.; Hagen-Plantinga, E.A.; Everts, H.; Bosch, Guido; Kema, I.P.; Hendriks, W.H.

    2012-01-01

    This paper reports the results of a cohort study and randomised clinical trial (RCT) in crossover design. In the cohort study, the range of urinary oxalate (Uox) and calcium (Uca) excretion was determined within a sample of the Dutch population of dogs and cats, and dietary and animal-related

  2. Synthesis, structure and luminescence property of 2D lanthanide complexes with 3-fluorophthalate and oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Yu-E [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Li, Xia, E-mail: xiali@mail.cnu.edu.cn [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Song, Shuang [Department of Chemistry, Capital Normal University, Beijing 100048 (China)

    2012-12-15

    Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (Ln=Sm 1, Eu 2, Tb 3 and Dy 4; fpht=3-fluorophthalate and ox=oxalate) have been synthesized and structurally characterized by single crystal X-ray diffraction. The four complexes possess similar 2D framework structures constructed from Ln-fpht double-stranded helices and ox linkages. Complexes 2 and 3 display the characteristic emission {sup 5}D{sub 0}{yields}{sup 7}F{sub J} (J=0-4) transitions of Eu(III) ion and {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=6-3) transitions of Tb(III) ion, respectively. The emission decay curves reveal a monoexponential behavior yielding the lifetime values of 0.266{+-}0.002 ms for 2 and 0.733{+-}0.002 ms for 3. The emission spectrum of 1 shows three weak bands corresponding to the characteristic emission {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 5/2}, {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} and {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 9/2} transitions of Sm(III) ion. The emission spectrum of 4 displays a broad band centered at 438 nm, which comes from the {pi}{sup Low-Asterisk }-{pi} transition of the ligand. - Graphical abstract: Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate, ox=oxalate) possess 2D structures. Sm(III), Eu(III) and Tb(III) complexes show the characteristic fluorescent emission of the Ln(III). Dy(III) complex displays ligand-based luminescent behavior. Highlights: Black-Right-Pointing-Pointer [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate; ox=oxalate) show 2D structures. Black-Right-Pointing-Pointer The 2D structures are constructed from Ln-fpht double-stranded helices and ox linkage. Black-Right-Pointing-Pointer The Sm(III), Eu(III) and Tb(III) complexes show the characteristic emission of the Ln(III) ions. Black-Right-Pointing-Pointer Dy(III) complex displays ligand-based luminescent behavior.

  3. Photocatalytic decomposition of perfluorooctanoic acid (PFOA) by TiO{sub 2} in the presence of oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuan, E-mail: wang_yuan@mail.tsinghua.edu.cn [State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Pengyi [State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2011-09-15

    Graphical abstract: In the presence of oxalic acid, perfluoroocatanoic acid (PFOA) was effectively decomposed over TiO{sub 2} with the irradiation of 254 nm UV light under nitrogen atmosphere. A possible reductive mechanism induced by carboxyl anion radicals (CO{sub 2}{center_dot}{sup -}) and photogenerated electron was proposed. Highlights: {yields} Perfluoroocatanoic acid (PFOA) was decomposed effectively over TiO{sub 2} with the irradiation of 254 nm UV light under nitrogen atmosphere in the presence of oxalic acid. {yields} Photogenerated electrons and carboxyl anion radicals (CO{sub 2}{center_dot}{sup -}) had the ability to induce the reductive decomposition of PFOA. {yields} Carboxyl anion radicals (CO{sub 2}{center_dot}{sup -}) in the photocatalytic process was confirmed by the electron paramagnetic resonance (EPR) measurements. {yields} The results of the addition of potassium persulfate (K{sub 2}S{sub 2}O{sub 8}), as an electron acceptor, validated the action of photogenerated electrons for the decomposition of PFOA. - Abstract: Heterogeneous photocatalytic decomposition of perfluoroocatanoic acid (PFOA) by TiO{sub 2} under 254 nm UV light was investigated. Adding oxalic acid as a hole-scavenger significantly accelerated PFOA decomposition under nitrogen atmosphere. Fluoride ion, formic acid and six shorter-chain perfluorinated carboxylic acids (PFCAs) bearing C{sub 2}-C{sub 7} were identified as intermediates. When using perchloric acid (HClO{sub 4}) as a replacement of oxalic acid to maintain the same pH of the reaction solution, PFOA did not decomposition efficiently. Compared with oxalic acid, potassium iodide (KI, another hole-scavenger) also led to a slower PFOA decomposition, while the addition of an electron acceptor (potassium persulfate, K{sub 2}S{sub 2}O{sub 8}) obviously inhibited PFOA decomposition. This suggested that oxalic acid played more than one role in PFOA decomposition rather than simply providing acidity and acting as a hole

  4. Effect of Postharvest Oxalic Acid and Calcium Chloride on Quality Attributes of Sweet Cherry (Prunus avium L.

    Directory of Open Access Journals (Sweden)

    M. Safa

    2016-02-01

    Full Text Available Introduction: Fruits and vegetables have special importance as a very important part of the human food supply. And from the beginnings of life, man has used these products to supply a part of his food. Nowadays, horticultural products are widely used in the diet. Cherry is one of the deciduous trees in the temperate regions, which is potassium rich. Use of Oxalic acid significantly reduces frost injury in pomegranate fruits during storage at a temperature of 2° C. In fruit trees, the importance of calcium is due to a delay in fruit ripening process and this way products have better portability. Materials and Methods: Firmness test was measured using the FT011 model of penetrometer. For determination of titratable acidity, the 0.1 N sodium hydroxide (NaOH titration method was used. Total Soluble solids content (SSC of fruit was measured by a digital refractometer (PAL-1. For determination of vitamin C in fruit juices, titration method with the indicator, 2,6-di-chlorophenolindophenol was used. Fruit juice pH was measured using pH meter model HI 9811.In order to investigate the effect of postharvest soaking treatment with Oxalic acid on the qualitative specifications and storage life of single grain sweet cherry fruit a research was conducted. This experience was conducted in a completely randomized design with 3 replications separately for the two materials. In this experiment Oxalic acid, in four levels (0,4,6 and 8 mM and Calcium chloride in four levels (0, 40, 55 and 70 mM were applied on the single grain sweet cherry fruit in the form of soaking and sampleswith7-day intervals for a period of 28 days from the fridge out and quanti tate and qualitative traits such as stiffness, weight loss, Titratable acidity, total soluble solids, vitamin C and pH were measured. Results and Discussion: The results showed that compared with control ones all of the concentrations of Oxalic acid and Calcium chloride caused significant differences in the amount

  5. Study of wet etching thin films of indium tin oxide in oxalic acid by monitoring the resistance

    Energy Technology Data Exchange (ETDEWEB)

    Mammana, Suelene S., E-mail: ssmammana@abinfo.com.br [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil); Greatti, Alessandra; Luiz, Francis H.; Costa, Francisca I. da; Mammana, Alaide P. [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil); Calligaris, Guilherme A.; Cardoso, Lisandro P. [Institute of Physics Gleb Wataghin, State University of Campinas-UNICAMP, CEP 13083-859, Campinas, SP (Brazil); Mammana, Carlos I.Z.; Engelsen, Daniel den [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil)

    2014-09-30

    We describe a study on wet etching of thin films of indium tin oxide (ITO) using a simple method by monitoring the resistance of the thin film in aqueous solutions of oxalic acid and hydrochloric acid. Generally three different regimes can be distinguished during etching ITO in acids: (1) initial etching, which is slow, (2) a fast etching phase and (3) slow etching stage at the end. These regimes are explained in terms of a porosity–roughness model. This porosity model has been confirmed largely by X-ray reflection measurements at grazing incidence, roughness measurements and scanning electron microscopy (SEM). A reliable method for monitoring the resistance during etching has been developed. This method is based on a 2-strips measuring jig with a very low series contact resistance. The activation energy of the etch rate of ITO films was found to be 80 ± 5 kJ/mol for oxalic acid and 56 ± 5 kJ/mol for HCl. SEM analyses in the final stage of the etching process indicate an enrichment of Sn in the residual film material. These observations are explained in terms of preferential etching of In{sub 2}O{sub 3}. X-ray analyses showed that the density of the ITO film decreased by etching. By adding ferric chloride to the oxalic acid solution we could accelerate the etch rate substantially. - Highlights: • Etching of indium tin oxide thin films by monitoring the resistance. • Oxalic acid has 2–3 times lower etch rate than concentrated HCl. • The etch rate in oxalic acid can be accelerated substantially by adding FeCl{sub 3}. • The proposed etching model for indium tin oxide was confirmed by X-ray analysis and scanning electron microscopy. • Energy Dispersive X-ray Spectroscopy analyses showed preferential etching of In{sub 2}O{sub 3}, enriching the film with SnO{sub 2}.

  6. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles

    Directory of Open Access Journals (Sweden)

    Yuniar Ponco Prananto

    2013-03-01

    Full Text Available Crystal growth of cobalt (II oxalate in silica gel at room temperature as precursor of Co3O4 nano particles has been studied. Specifically, this project is focusing on the use of two different reaction tube types toward crystallization of cobalt (II oxalate in gel. The gel was prepared at pH 5 by reacting sodium metasilicate solution with dilute nitric acid (for U-tube and oxalic acid (for straight tube, with gelling time of 4 days and crystal growth time of 8 (for straight tube and 12 (for U-tube weeks. Result shows that pink crystalline powder was directly formed using straight tube method. The use of different solvents in straight tube method affects crystallization and could delay direct precipitation of the product. In contrast, bigger and better shape of red block crystal was yielded from U-tube method; however, longer growth time was needed. FTIR studies suggest that both growth method produces identical compound of hydrated cobalt (II oxalate. © 2013 BCREC UNDIP. All rights reservedReceived: 25th October 2012; Revised: 30th November 2012; Accepted: 5th December 2012[How to Cite: Y.P. Prananto, M.M. Khunur, D.T. Wahyuni, R.A. Shobirin, Y.R. Nata, E. Riskah, (2013. Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 198-204. (doi:10.9767/bcrec.7.3.4066.198-204][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4066.198-204 ] View in  |

  7. Real-Time Studies of Iron Oxalate-Mediated Oxidation of Glycolaldehyde as a Model for Photochemical Aging of Aqueous Tropospheric Aerosols.

    Science.gov (United States)

    Thomas, Daniel A; Coggon, Matthew M; Lignell, Hanna; Schilling, Katherine A; Zhang, Xuan; Schwantes, Rebecca H; Flagan, Richard C; Seinfeld, John H; Beauchamp, J L

    2016-11-15

    The complexation of iron(III) with oxalic acid in aqueous solution yields a strongly absorbing chromophore that undergoes efficient photodissociation to give iron(II) and the carbon dioxide anion radical. Importantly, iron(III) oxalate complexes absorb near-UV radiation (λ > 350 nm), providing a potentially powerful source of oxidants in aqueous tropospheric chemistry. Although this photochemical system has been studied extensively, the mechanistic details associated with its role in the oxidation of dissolved organic matter within aqueous aerosol remain largely unknown. This study utilizes glycolaldehyde as a model organic species to examine the oxidation pathways and evolution of organic aerosol initiated by the photodissociation of aqueous iron(III) oxalate complexes. Hanging droplets (radius 1 mm) containing iron(III), oxalic acid, glycolaldehyde, and ammonium sulfate (pH ∼3) are exposed to irradiation at 365 nm and sampled at discrete time points utilizing field-induced droplet ionization mass spectrometry (FIDI-MS). Glycolaldehyde is found to undergo rapid oxidation to form glyoxal, glycolic acid, and glyoxylic acid, but the formation of high molecular weight oligomers is not observed. For comparison, particle-phase experiments conducted in a laboratory chamber explore the reactive uptake of gas-phase glycolaldehyde onto aqueous seed aerosol containing iron and oxalic acid. The presence of iron oxalate in seed aerosol is found to inhibit aerosol growth. These results suggest that photodissociation of iron(III) oxalate can lead to the formation of volatile oxidation products in tropospheric aqueous aerosols.

  8. Activated carbon enhanced ozonation of oxalate attributed to HO oxidation in bulk solution and surface oxidation: effect of activated carbon dosage and pH.

    Science.gov (United States)

    Xing, Linlin; Xie, Yongbing; Minakata, Daisuke; Cao, Hongbin; Xiao, Jiadong; Zhang, Yi; Crittenden, John C

    2014-10-01

    Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon (AC) in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals (HO) in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol (tBA) with low dosages of AC, while it was hardly affected by tBA when the AC dosage was greater than 0.3g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05g/L, but it did not work when the AC dosage was no less than 0.1g/L. These observations indicate that HO in bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HO oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HO oxidation in basic bulk solution. A mechanism involving both HO oxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.

  9. Synthesis of Flower-like Zinc Oxalate Microspheres in Ether-water Bilayer Refluxing Systems and Their Conversion to Zinc Oxide Microspheres

    Institute of Scientific and Technical Information of China (English)

    Liang Ni; Lei Wang; Bing Shao; Yinjue Wang; Wenli Zhang; Yong Jiang

    2011-01-01

    Flower-like zinc oxalate with a mean diameter of 50 μm was synthesized via the reaction of zinc acetate and dimethyl oxalate in ether-water bilayer refluxing systems at low temperature. Flower-like zinc oxalate microspheres can be further transformed into the similar morphology to zinc oxide by the decomposition of zinc oxalate at 500℃. Scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysisdifferential scanning calorimetric (TG-DSC), energy dispersive X-ray spectrum (EDX) and Fourier transforminfrared spectroscopy (FT-IR) were used to characterize the structure features and chemical compositions of the as-synthesized products. The UV-Vis and photoluminescence spectrum of flower-like zinc oxide microspheres were studied. The experimental results showed that flower-like zinc oxalate microspheres may be self-assembled by the zinc oxalate flakes. The ether-water volume ratio of 4:1 and refluxing temperature of 40℃ wereconsidered to favor the preparation of flower-like zinc oxalate microspheres.

  10. Synthesis and photochromic properties of WO3 powder induced by oxalic acid

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi; ZHU Hua; HUANG Rong; ZHAO Li; YAN ShaNing

    2009-01-01

    Tungsten trioxide powder with the novel morphology was prepared via the hydrothermal method with oxalic acid as the organic inducer, the structure and shape of which were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. Furthermore, photochromic properties of the as-prepared powder samples were tested by an ultraviolet-visible spectrophotometer combined with a color difference meter. The corresponding results indicated that the induced product was still hex- agonal WO3, made up of regularly spindle particles with 200--300 nm in length and 30--50 nm in width. The ratio of the length and width was from 4 to 10. Moreover, the special morphology improved its ab-sorptive capacity to the excitation light source, resulting in its high photochromic properties.

  11. Synthesis and photochromic properties of WO3 powder induced by oxalic acid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Tungsten trioxide powder with the novel morphology was prepared via the hydrothermal method with oxalic acid as the organic inducer, the structure and shape of which were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. Furthermore, photochromic properties of the as-prepared powder samples were tested by an ultraviolet-visible spectrophotometer combined with a color difference meter. The corresponding results indicated that the induced product was still hexagonal WO3, made up of regularly spindle particles with 200-300 nm in length and 30-50 nm in width. The ratio of the length and width was from 4 to 10. Moreover, the special morphology improved its absorptive capacity to the excitation light source, resulting in its high photochromic properties.

  12. Tracer studies of anodic films formed on aluminium in malonic and oxalic acids

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Vergara, S.J. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: s.garcia-vergara@manchester.ac.uk; Skeldon, P.; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Habakaki, H. [Graduate School of Engineering, Hokkaido University, N13-W8, Sapporo 060-8628 (Japan)

    2007-12-30

    Using a tungsten-containing layer, incorporated into sputtering-deposited aluminium, as a tracer, the growth of porous anodic films in malonic and oxalic acid electrolytes has been investigated using transmission electron microscopy, Rutherford backscattering spectroscopy and nuclear reaction analysis. Comparisons were also made with films formed in phosphoric acid electrolyte, which have been studied previously. The findings reveal a distortion of the tracer layer within the barrier region of the porous films, evident as a lagging of the tracer beneath the pores relative to that in the adjacent cell wall region. Further, the films are significantly thicker than the layer of metal consumed during anodizing and display smooth-sided pores. The anodizing behaviours are consistent with a major role for field-assisted flow of film material within the barrier layer in the development of the pores.

  13. Optimization of thorium oxalate precipitation conditions relative to thorium oxide sinterability

    Energy Technology Data Exchange (ETDEWEB)

    White, G.D.; Bray, L.A.; Hart, P.E.

    1980-01-01

    The effect of thorium oxalate precipitation conditions on derived oxide sinterability was investigated with the objective of producing ThO/sub 2/ powder that could be sintered to high density without premilling. Precipitation conditions examined were temperature, digestion time and agitation method which were employed in a two-level factorial experimental design to delineate their effects. The two levels for each of the factors, respectively, were 10/sup 0/C and 70/sup 0/C, 15 min and 360 min, and mechanical stirrer and a homogenizer that imparted both mechanical and ultrasonic agitation. The ThO/sub 2/ derived from each of the precipitation trials was characterized with respect to morphology, surface area, and crystallite size as well as sinterability. Only precipitation temperature had a significant effect upon all the properties of the derived oxide powders.

  14. Self-Ordered Nanoporous Alumina Templates Formed by Anodization of Aluminum in Oxalic Acid

    Science.gov (United States)

    Vida-Simiti, Ioan; Nemes, Dorel; Jumate, Nicolaie; Thalmaier, Gyorgy; Sechel, Niculina

    2012-10-01

    Anodic aluminum oxide (AAO) membranes with highly ordered nanopores serve as ideal templates for the formation of various nanostructured materials. The procedure of the template preparation is based on a two-step self-organized anodization of aluminum. In the current study, AAO templates were fabricated in 0.3 M oxalic acid under the anodizing potential range of 30-60 V at an electrolyte temperature of ~5°C. The AAO templates were analyzed using scanning electron microscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, and differential thermal analysis. The as obtained layers are amorphous; the mean pore size is between 40 nm and 75 nm and increases with the increase of the anodization potential. Well-defined pores across the whole aluminum template, a pore density of ~1010 pores/cm2, and a tendency to form a porous structure with hexagonal symmetry were observed.

  15. Kinetics and mechanism of the oxidation of formic and oxalic acids by quinolinium fluorochromate

    Indian Academy of Sciences (India)

    Madhu Khurana; Pradeep K Sharma; Kalyan K Banerji

    2000-04-01

    Kinetics and mechanism of oxidation of formic and oxalic acids by quinolinium fluorochromate (QFC) have been studied in dimethylsulphoxide. The main product of oxidation is carbon dioxide. The reaction is first-order with respect to QFC. Michaelis-Menten type of kinetics were observed with respect to the reductants. The reaction is acid-catalysed and the acid dependence has the form: obs = + [H+]. The oxidation of -deuterioformic acid exhibits a substantial primary kinetic isotope effect (H/D = 6.01 at 303 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft’s and Swain’s multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical cyclic transition state in the rate-determining step. Suitable mechanisms have been proposed

  16. Papillary and Nonpapillary Calcium Oxalate Monohydrate Renal Calculi: Comparative Study of Etiologic Factors

    Directory of Open Access Journals (Sweden)

    Enrique Pieras

    2006-01-01

    Full Text Available Calcium oxalate monohydrate (COM renal calculi can be classified into two groups: papillary and nonpapillary. In this paper, a comparative study between etiologic factors of COM papillary and nonpapillary calculi is performed. The study included 40 patients with COM renal calculi. The urine of these individuals was analyzed. Case history, lifestyle, and dietetic habits were obtained.No significant differences between urinary biochemical data of both groups were observed; 50% of COM papillary stone formers and 40% of COM nonpapillary stone formers had urolithiasis family history. A low consumption of phytate-rich products was observed for both groups. A relationship between profession with occupational exposure to cytotoxic products and COM papillary renal lithiasis was detected.The results suggest that COM papillary calculi would be associated to papillary epithelium alterations together with a crystallization inhibitors deficit, whereas COM nonpapillary calculi would be associated to the presence of heterogeneous nucleants and a crystallization inhibitors deficit.

  17. Description of Mechanism Function about Dehydration of Cobalt Oxalate Dihydrate by Multiple Rates Isotemperature Method

    Institute of Scientific and Technical Information of China (English)

    Li Li-qing; Chen Dong-hua

    2004-01-01

    A new method of the multiple rates isotemperature is proposed to define the most probable mechanism g(α) of thermal analysis; the iterative isoconversional procedure has been employed to estimate apparent activation energy E; the pre-exponential factor A is obtained on the basis of E and g(α). By this new method, the thermal analysis kinetics triplet of dehydration of cobalt oxalate dihydrate is determined, apparent activation energy E is 99.84 kJ\\5mol-1; pre-exponential factor A is 3.427×109-3.872×109 s-1 and the most probable mechanism belongs to nucleation and growth, Am model, the range of m is from 1.50 to 1.70.

  18. Degradation of azurite in mural paintings: distribution of copper carbonate, chlorides and oxalates by SRFTIR

    Science.gov (United States)

    Lluveras, A.; Boularand, S.; Andreotti, A.; Vendrell-Saz, M.

    2010-05-01

    This article illustrates the analysis by synchrotron micro-analytical techniques of an azurite painting presenting greenish chromatic degradation. The challenge of the experiments was to obtain the spatial distribution of the degradation products of azurite. Copper hydroxychlorides, carbonates and copper oxalates have been mapped by SR FTIR imaging of cross sections in transmission mode. To complement the information, Py/GC/MS and GC/MS techniques were applied in order to characterize the binding media and organic materials present as well as their degradation products. Results contribute to a better understanding of the decay of blue areas in ancient paintings not only from the particular point of view of azurite weathering, but also by adding information regarding the oxalates’ formation and their distribution in painting samples. Synchrotron radiation demonstrates its capability for the mapping in painting cross sections.

  19. Photodegradation of bisphenol A in Fe(Ⅲ)-oxalate complexes solution

    Institute of Scientific and Technical Information of China (English)

    ZHAN Man-jun; YANG Xi; XIAN Qi-ming; KONG Ling-ren

    2006-01-01

    The aqueous photodegradation of bisphenol A (BPA) in the presence of Fe(Ⅲ)-oxalate complexes (Fe(Ⅲ)-Ox), which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe(Ⅲ)-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial processes of Fe(Ⅲ)-Ox complexes and contributed to the photooxidation of BPA, were determined by molecular probe and electron spin resonance (ESR) methods with the steady-state concentration of 2.56 × 10-14 mol/L. Superoxide anion radical (O2.-) was consistructural analysis of the intermediate photoproducts of BPA in Fe(Ⅲ)-Ox complexes solution, the possible degradation pathways of of Fe(Ⅲ) may affect the environmental fate of BPA in natural water significantly.

  20. Synthesis and magnetic properties of one-dimensional metal oxalate networks as molecular-based magnets

    Indian Academy of Sciences (India)

    B P Singh; B Singh

    2000-02-01

    The homo- and heteropolymetallic assemblies of MM′(OX)2(H2O)4, where MM′ represents MnMn, CoMn, NiMn, CuMn, CoCo, NiCo, CuCo, NiNi, CuNi, and CuCu; and the respective complexes, numbered 1–10, have been prepared by reacting metal(II) salts—i.e. of Mn, Co, Ni, and Cu—and potassium oxalate monohydrate in hot water (90–100°C). The magnetic susceptibility data of the complexes 8 and 9 in the 300 K–20 K temperature range obeys the Curie–Weiss law and exhibits Weiss constants – 50 K and – 100 K, respectively. On lowering the temperature, the effective magnetic moment decreases gradually and is indicative of antiferromagnetic phase transition. The complexes have also been characterized by ES mass spectrometry, infrared (IR), electronic, and electron spin resonance (ESR) spectra.

  1. SYNTHESIS, THERMAL STUDIES AND CRYSTAL STRUCTURE OF 4-AMINOPYRIDINIUM SEMI-OXALATE HEMIHYDRATE

    Directory of Open Access Journals (Sweden)

    CECILIA CHACÓN

    2017-06-01

    Full Text Available The title compound has been synthesized by grinding in an agate mortar. Its structure was characterized by TGA-DSC studies and single-crystal X-ray diffraction. This compound crystallize in the monoclinic system with space group C2/c, Z = 4, and unit cell parameters a = 16.109(2 Å, b = 5.748(7 Å, c = 20.580(3 Å, β = 107.36(1°. The salt, C2HO4-.C5H7N+.0.5 H2O, is an ionic ensemble assisted by hydrogen bonds established between 4-aminopyridinium cations, oxalate anions and water molecules. The three components thus construct a supramolecular assembly with a three-dimensional hydrogen bonded framework.

  2. Energy transfer and thermal studies of Pr3+ doped cerium oxalate crystals

    Indian Academy of Sciences (India)

    R Pragash; Gijo Jose; N V Unnikrishnan; C Sudarsanakumar

    2011-07-01

    Energy transfer process at room temperature for cerium (sensitizer) oxalate single crystals doped with different concentrations (10, 13, 15, 17 and 20%) of praseodymium ions (activator) grown by hydro silica gel method has been evaluated. The analysis of energy level diagrams of cerium and praseodymium ions indicates that the energy gap between the sensitizer and the activator ions varies in a small range suggesting a possible energy transfer from the Ce3+ to Pr3+. The emission and absorption spectra of these crystals were recorded. The overlapping of the absorption spectra of Pr3+ and emission spectra of Ce3+ at wavelengths 484 and 478 nm, respectively, strongly supports the possible energy transfer process in this system. From the absorption spectra, oscillator strength, electric dipole moment, branching ratio and Judd–Ofelt parameters of this system were evaluated by least square programming. The quantum efficiency, energy transfer probabilities and thermal properties have been studied.

  3. Oxalic acid alleviates chilling injury in peach fruit by regulating energy metabolism and fatty acid contents.

    Science.gov (United States)

    Jin, Peng; Zhu, Hong; Wang, Lei; Shan, Timin; Zheng, Yonghua

    2014-10-15

    The effects of postharvest oxalic acid (OA) treatment on chilling injury, energy metabolism and membrane fatty acid content in 'Baifeng' peach fruit stored at 0°C were investigated. Internal browning was significantly reduced by OA treatment in peaches. OA treatment markedly inhibited the increase of ion leakage and the accumulation of malondialdehyde. Meanwhile, OA significantly increased the contents of adenosine triphosphate and energy charge in peach fruit. Enzyme activities of energy metabolism including H(+)-adenosine triphosphatase, Ca(2+)-adenosine triphosphatase, succinic dehydrogenase and cytochrome C oxidase were markedly enhanced by OA treatment. The ratio of unsaturated/saturated fatty acid in OA-treated fruit was significantly higher than that in control fruit. These results suggest that the alleviation in chilling injury by OA may be due to enhanced enzyme activities related to energy metabolism and higher levels of energy status and unsaturated/saturated fatty acid ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Calcium Oxalate Stone Agglomeration Inhibition [tm] Reflects Renal Stone-Forming Activity

    Science.gov (United States)

    Lindberg, Jill S.; Cole, Francis E.; Romani, William; Husserl, Fred E.; Fuselier, Harold A.; Kok, Dirk J.; Erwin, Donald T.

    2000-01-01

    Louisiana and other Gulf South states comprise a “Stone Belt” where calcium oxalate stone formers (CaOx SFs) are found at a high rate of approximately 5%. In these patients, the agglomeration of small stone crystals, which are visible in nearly all morning urine collections, forms stones that can become trapped in the renal parenchyma and the renal pelvis. Without therapy, about half of CaOx SFs repeatedly form kidney stones, which can cause excruciating pain that can be relieved by passage, fragmentation (lithotripsy), or surgical removal. The absence of stones in “normal” patients suggests that there are stone inhibitors in “normal” urines. At the Ochsner Renal Stone Clinic, 24-hour urine samples are collected by the patient and sent to the Ochsner Renal Stone Research Program where calcium oxalate stone agglomeration inhibition [tm] measurements are performed. Urine from healthy subjects and inactive stone formers has demonstrated strongly inhibited stone growth [tm] in contrast to urine from recurrent CaOx SFs. [tm] data from 1500 visits of 700 kidney stone patients have been used to evaluate the risk of recurrence in Ochsner's CaOx SF patients. These data have also been used to demonstrate the interactive roles of certain identified urinary stone-growth inhibitors, citrate and Tamm-Horsfall protein (THP), which can be manipulated with medication to diminish recurrent stone formation. Our goal is to offer patients both financial and pain relief by reducing their stones with optimized medication, using medical management to avoid costly treatments. PMID:21811395

  5. Wu-Ling-San formula prophylaxis against recurrent calcium oxalate nephrolithiasis - a prospective randomized controlled trial.

    Science.gov (United States)

    Lin, Eugene; Ho, Lin; Lin, Mao-Sheng; Huang, Min-Ho; Chen, Wen-Chi

    2013-01-01

    Wu-Ling-San (WLS) formula has been proved to prevent calcium oxalate nephrolithiasis both in vitro and in vivo. This is the first prospective, randomized and placebo-controlled clinical trial of WLS in calcium oxalate nephrolithiasis prevention. All patients who enrolled were asked to drink enough fluid to urinate at least 2 L daily during the study period. A 24-hour urine collection was performed to establish the baseline levels of multiple urinary parameters before taking the medicine. The patients were randomized and divided into two groups. The medication group took 2 gm WLS formula three times daily for 1 month. The control group took 2 gm placebo three times daily for 1 month. A 24-hour urine collection was performed to evaluate multiple urinary and serum parameters from all patients during the study period. A total of 39 patients were enrolled and 28 patients completed the study. Fourteen patients were allocated to WLS group and 14 patients to placebo group. After treatment, the mean urine output level increased to 2796.4 ± 525.7 ml/day (percentage of change, 13.9 %) in the WLS formula group. With placebo therapy, the mean decreased slightly to 2521.4 ± 762.7ml/day (percentage of change, -5.7 %). The percentage of change was significantly different between the two groups (independent t-test, P=0.02). No patient complained of side effects, such as fatigue, dizziness, musculoskeletal symptoms, or gastrointestinal disturbance. WLS formula is a promising adjunct to surgical and medical management of kidney stones. Active therapy with WLS formula has a positive effect on diuresis without leading to electrolyte imbalance.

  6. Variations in Tannin and Oxalic acid Content in Terminalia arjuna (Arjuna Bark

    Directory of Open Access Journals (Sweden)

    A K Pandey

    2009-01-01

    Full Text Available Terminalia arjuna (Arjuna, belonging to family combretaceae, grows along the streams or rivers and often in the shallow streambeds and riverbeds in central India. It has been considered by the Ayurvedic physicians as well as by the modern practitioners as a cardiac tonic. Clinical evaluation indicated that it has been found beneficial in the treatment of coronary artery disease, heart failure, and possibly hypercholesterolemia. It has also been found to possess antibacterial, antimutagenic and antioxidant activities. Demand for T. arjuna bark, both in India and abroad has been increasing rapidly for over a decade. About 95 percent of the requirement is met from the wild and collected in a pattern that is not concomitant with sustainable harvesting practices. The quality of the bark is directly dependent on harvesting technique and time. There is also a clear relationship between the part of the plant harvested, harvesting method used, and the impact of these on the plant. Keeping above into consideration it has been planned to carry out systematic study on phytochemical investigation of Arjuna bark collected from various parts of the tree at different harvesting time. The bark samples were analyzed for tannin and oxalic acid. The tannin and oxalic acid content varied from 6.75 to 14.82 % and 7.66 to 20.05 % respectively in various samples of T. arjuna bark collected from various places of Madhya Pradesh. The middle-aged trees having GBH around 130 cm were found to contain more amount of tannin. The study gives important information to obtain better quality of T. arjuna bark on sustainable basis.

  7. Nephroprotective effect of Corn Silk extract on oxalic acid-induced nephrocalcinosis in rabbit model

    Directory of Open Access Journals (Sweden)

    Faruk Hassan Al-Jawad

    2012-04-01

    Full Text Available ABSTRACT Background : Nephrocalcinosis is a state of deposition of calcium phosphate or oxalate in the renal parenchyma. It may occur in patients with renal tubular acidosis, vitamin D intoxication, and hyperparathyroidism. Corn silk was used in traditional Chinese medicine to relieve renal pains. Aim: To evaluate the effect of Corn silk aqueous extract in reducing calcium deposits from renal parenchyma in oxalic acid-induced nephrocalcinosis model. Materials and methods: Fourteen healthy rabbits were allocated to two groups. Two hours before induction of nephrocalcinosis, one group received water and the other received aqueous extract of corn silk and continued feeding for ten days. Blood samples were collected for biochemical analysis before induction and in the fifth and tenth post-induction day. Urine samples were taken to estimate urinary ca+2 levels and crystals. The histopathological examination was carried to check for crystal deposits in renal tissues. Results: Corn silk aqueous extract produced a significant reduction of blood urea nitrogen(5.2+/-0.08 vs 7.3+/-0.2 mmol/l, serum creatinine (85.9+/-0.2 vs 97.3+/-0.5 mmol/l and serum Na+ levels (137+/-0.2 vs 142.16+/-0.7 mmol/l with non-significant reduction in serum K+ (4.0+/-0.02 vs 4.2+/-0.05. There is a significant reduction in calcium deposition in renal parenchyma in comparison to the control group after ten days of treatment. Conclusion: Corn silk had a significant diuretic effect that accelerates the excretion of urinary calcium. [J Intercult Ethnopharmacol 2012; 1(2.000: 75-78

  8. Heterogeneous uptake of ammonia and dimethylamine into sulfuric and oxalic acid particles

    Science.gov (United States)

    Sauerwein, Meike; Keung Chan, Chak

    2017-05-01

    Heterogeneous uptake is one of the major mechanisms governing the amounts of short-chain alkylamines and ammonia (NH3) in atmospheric particles. Molar ratios of aminium to ammonium ions detected in ambient aerosols often exceed typical gas phase ratios. The present study investigated the simultaneous uptake of dimethylamine (DMA) and NH3 into sulfuric and oxalic acid particles at gaseous DMA / NH3 molar ratios of 0.1 and 0.5 at 10, 50 and 70 % relative humidity (RH). Single-gas uptake and co-uptake were conducted under identical conditions and compared. Results show that the particulate dimethyl-aminium/ammonium molar ratios (DMAH / NH4) changed substantially during the uptake process, which was severely influenced by the extent of neutralisation and the particle phase state. In general, DMA uptake and NH3 uptake into concentrated H2SO4 droplets were initially similarly efficient, yielding DMAH / NH4 ratios that were similar to DMA / NH3 ratios. As the co-uptake continued, the DMAH / NH4 gradually dropped due to a preferential uptake of NH3 into partially neutralised acidic droplets. At 50 % RH, once the sulfate droplets were neutralised, the stronger base DMA displaced some of the ammonium absorbed earlier, leading to DMAH / NH4 ratios up to four times higher than the corresponding gas phase ratios. However, at 10 % RH, crystallisation of partially neutralised sulfate particles prevented further DMA uptake, while NH3 uptake continued and displaced DMAH+, forming almost pure ammonium sulfate. Displacement of DMAH+ by NH3 has also been observed in neutralised, solid oxalate particles. The results can explain why DMAH / NH4 ratios in ambient liquid aerosols can be larger than DMA / NH3, despite an excess of NH3 in the gas phase. An uptake of DMA to aerosols consisting of crystalline ammonium salts, however, is unlikely, even at comparable DMA and NH3 gas phase concentrations.

  9. Slow relaxation of the magnetization in non-linear optical active layered mixed metal oxalate chains.

    Science.gov (United States)

    Cariati, Elena; Ugo, Renato; Santoro, Giuseppe; Tordin, Elisa; Sorace, Lorenzo; Caneschi, Andrea; Sironi, Angelo; Macchi, Piero; Casati, Nicola

    2010-12-06

    New Co(II) members of the family of multifunctional materials of general formula [DAMS](4)[M(2)Co(C(2)O(4))(6)]·2DAMBA·2H(2)O (M(III) = Rh, Fe, Cr; DAMBA = para-dimethylaminobenzaldehyde and [DAMS(+)] = trans-4-(4-dimethylaminostyryl)-1-methylpyridinium) have been isolated and characterized. Such new hybrid mixed metal oxalates are isostructural with the previously investigated containing Zn(II), Mn(II), and Ni(II). This allows to preserve the exceptional second harmonic generation (SHG) activity, due to both the large molecular quadratic hyperpolarizability of [DAMS(+)] and the efficiency of the crystalline network which organizes [DAMS(+)] into head-to-tail arranged J-type aggregates, and to further tune the magnetic properties. In particular, the magnetic data of the Rh(III) derivative demonstrate that high spin octacoordinated Co(II) centers behave very similarly to the hexacoordinated Co(II) ones, being dominated by a large orbital contribution. The Cr(III) derivative is characterized by ferromagnetic Cr(III)-Co(II) interactions. Most relevantly, the Fe(III) compound is characterized by a moderate antiferromagnetic interaction between Fe(III) and Co(II), resulting in a ferrimagnetic like structure. Its low temperature dynamic magnetic properties were found to follow a thermally activated behavior (τ(0) = 8.6 × 10(-11) s and ΔE = 21.4 K) and make this a candidate for the second oxalate-based single chain magnet (SCM) reported up to date, a property which in this case is coupled to the second order non linear optical (NLO) ones.

  10. Calcium oxalate monohydrate crystals internalized into renal tubular cells are degraded and dissolved by endolysosomes.

    Science.gov (United States)

    Chaiyarit, Sakdithep; Singhto, Nilubon; Thongboonkerd, Visith

    2016-02-25

    Interaction between calcium oxalate crystals and renal tubular cells has been recognized as one of the key mechanisms for kidney stone formation. While crystal adhesion and internalization have been extensively investigated, subsequent phenomena (i.e. crystal degradation and dissolution) remained poorly understood. To explore these mechanisms, we used fluorescein isothiocyanate (FITC)-labelled calcium oxalate monohydrate (COM) crystals (1000 μg/ml of crystals/culture medium) to confirm crystal internalization into MDCK (Type II) renal tubular cells after exposure to the crystals for 1 h and to trace the internalized crystals. Crystal size, intracellular and extracellular fluorescence levels were measured using a spectrofluorometer for up to 48 h after crystal internalization. Moreover, markers for early endosome (Rab5), late endosome (Rab7) and lysosome (LAMP-2) were examined by laser-scanning confocal microscopy. Fluorescence imaging and flow cytometry confirmed that FITC-labelled COM crystals were internalized into MDCK cells (14.83 ± 0.85%). The data also revealed a reduction of crystal size in a time-dependent manner. In concordance, intracellular and extracellular fluorescence levels were decreased and increased, respectively, indicating crystal degradation/dissolution inside the cells and the degraded products were eliminated extracellularly. Moreover, Rab5 and Rab7 were both up-regulated and were also associated with the up-regulated LAMP-2 to form large endolysosomes in the COM-treated cells at 16-h after crystal internalization. We demonstrate herein, for the first time, that COM crystals could be degraded/dissolved by endolysosomes inside renal tubular cells. These findings will be helpful to better understand the crystal fate and protective mechanism against kidney stone formation.

  11. Oxalate content of silver beet leaves (Beta vulgaris var. cicla) at different stages of maturation and the effect of cooking with different milk sources.

    Science.gov (United States)

    Simpson, Thomas S; Savage, Geoffrey P; Sherlock, Robert; Vanhanen, Leo P

    2009-11-25

    The work presented here indicates that people who have a tendency to develop kidney stones should avoid consuming regrowth and developed silver beet (Beta vulgaris var. cicla) leaves. Soluble oxalate contents of leaves range from 58% of the total oxalate for the mature leaves up to 89% for the regrowth tissue, with regrowth tissue containing the highest levels of soluble oxalate at 7267+/-307 mg/100 g of dry matter (DM). Leaves cooked in milk contained significantly (pbeet, a low fat milk cooking medium with neutral pH should be utilized.

  12. ACTUAL-WASTE TESTS OF ENHANCED CHEMICAL CLEANING FOR RETRIEVAL OF SRS HLW SLUDGE TANK HEELS AND DECOMPOSITION OF OXALIC ACID

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; King, W.; Ketusky, E.

    2012-01-12

    Savannah River National Laboratory conducted a series of tests on the Enhanced Chemical Cleaning (ECC) process using actual Savannah River Site waste material from Tanks 5F and 12H. Testing involved sludge dissolution with 2 wt% oxalic acid, the decomposition of the oxalates by ozonolysis (with and without the aid of ultraviolet light), the evaporation of water from the product, and tracking the concentrations of key components throughout the process. During ECC actual waste testing, the process was successful in decomposing oxalate to below the target levels without causing substantial physical or chemical changes in the product sludge.

  13. Removal of aqueous oxalic acid by heterogeneous catalytic ozonation with MnOx/sewage sludge-derived activated carbon as catalysts.

    Science.gov (United States)

    Huang, Yuanxing; Sun, Yaru; Xu, Zhihua; Luo, Mengyu; Zhu, Chunlei; Li, Liang

    2017-01-01

    MnOx/sewage sludge-derived activated carbon (MnOx/SAC) was prepared as catalysts to improve the performance of aqueous oxalic acid degradation by ozonation. The results indicated that MnOx/SAC had excellent catalytic activity in mineralization of oxalic acid during heterogeneous catalytic ozonation process. MnOx/SAC with a manganese load of 30% exhibited the strongest catalytic activity under the condition of solution pH3.5, which enhanced the oxalic acid removal from 10.3% to 92.2% in 60min compared with that treated by ozone alone. Increase of catalyst dosage and aqueous ozone concentration was advantageous for oxalic acid removal from water. On the basis of catalyst characterization analysis and the observation of inhibitory effect induced by higher pH, less catalyst dosage as well as the presence of hydroxyl radical scavenger, it was deduced that the reaction mechanism involved both hydroxyl radicals attack and surface reactions.

  14. Secondary formation of oxalic acid and related organic species from biogenic sources in a larch forest at the northern slope of Mt. Fuji

    Science.gov (United States)

    Mochizuki, Tomoki; Kawamura, Kimitaka; Miyazaki, Yuzo; Wada, Ryuichi; Takahashi, Yoshiyuki; Saigusa, Nobuko; Tani, Akira

    2017-10-01

    To better understand the formation of water-soluble organic aerosols in the forest atmosphere, we measured low molecular weight (LMW) dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, unsaturated fatty acids (UFAs), and water-soluble organic carbon (WSOC) in aerosols from a Larix kaempferi forest located at the northern slope of Mt. Fuji, Japan, in summer 2012. Concentrations of dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and WSOC showed maxima in daytime. Relative abundance of oxalic acid in LMW dicarboxylic acids was on average 52% and its average concentration was 214 ng m-3. We found that diurnal and temporal variations of oxalic acid are different from those of isoprene and α-pinene, whereas biogenic secondary organic aerosols (BSOAs) derived from isoprene and α-pinene showed similar variations with oxalic acid. The mass concentration ratios of oxalic acid/BSOAs were relatively constant, although a large variation in the concentrations of toluene that is an anthropogenic volatile organic compound was observed. These results suggest that formation of oxalic acid is associated with the oxidation of isoprene and α-pinene with O3 and other oxidants in the forest atmosphere. In addition, concentrations of UFAs were observed, for the first time, to decrease dramatically during daytime in the forest. Mass concentration ratios of azelaic acid to UFAs showed a positive correlation with O3, suggesting that UFAs are oxidized to yield azelaic acid, which may be further decomposed to oxalic acid in the forest atmosphere. We found that contributions of oxalic acid to WSOC are significantly high ranging from 3.7 to 9.7% (average 6.0%). This study demonstrates that forest ecosystem is an important source of oxalic acid and other dicarboxylic acids in the atmosphere.

  15. Antilithiatic Activity of phlorotannin rich extract of Sarghassum Wightii on Calcium Oxalate Urolithiais – In Vitro and In VivoEvaluation

    Directory of Open Access Journals (Sweden)

    D. Sujatha

    2015-06-01

    Full Text Available ABSTRACTPurpose:Urolithiasis is a common urological disorder responsible for serious human affliction and cost to the society with a high recurrence rate. The aim of the present study was to systematically evaluate the phlorotannin rich extract of Sargassum wightii using suitable in vitro and in vivo models to provide scientific evidence for its antilithiatic activity.Materials and Methods:To explore the effect of Sargassum wightii on calcium oxalate crystallization, in vitro assays like crystal nucleation, aggregation and crystal growth were performed. Calcium oxalate urolithiasis was induced in male Sprague dawley rats using a combination of gentamicin and calculi producing diet (5% ammonium oxalate and rat pellet feed. The biochemical parameters like calcium, oxalate, magnesium, phosphate, sodium and potassium were evaluated in urine, serum and kidney homogenates. Histopathological studies were also done to confirm the biochemical findings.Results:The yield of Sargassum wightii extract was found to be 74.5 gm/kg and confirmed by quantitative analysis. In vitro experiments with Sargassum wightii showed concentration dependent inhibition of calcium oxalate nucleation, aggregation and growth supported by SEM analysis. In the in vivo model, Sargassum wightiireduced both calcium and oxalate supersaturation in urine, serum and deposition in the kidney. The biochemical results were supported by histopathological studies.Conclusion:The findings of the present study suggest that Sargassum wightii has the ability to prevent nucleation, aggregation and growth of calcium oxalate crystals. Sargassum wightii has better preventive effect on calcium oxalate stone formation indicating its strong potential to develop as a therapeutic option to prevent recurrence of urolithiasis.

  16. Real-Time Studies of Iron Oxalate-Mediated Oxidation of Glycolaldehyde as a Model for Photochemical Aging of Aqueous Tropospheric Aerosols

    OpenAIRE

    Thomas, Daniel A.; Coggon, Matthew M.; Lignell, Hanna; Schilling, Katherine Ann; Zhang, Xuan; Schwantes, Rebecca H.; Flagan, Richard C.; Seinfeld, John H.; Beauchamp, Jesse Lee

    2016-01-01

    The complexation of iron (III) with oxalic acid in aqueous solution yields a strongly absorbing chromophore that undergoes efficient photodissociation to give iron (II) and the carbon dioxide anion radical. Importantly, iron (III) oxalate complexes absorb near-UV radiation (λ > 350 nm), providing a potentially powerful source of oxidants in aqueous tropospheric chemistry. Although this photochemical system has been studied extensively, the mechanistic details associated with its role in the o...

  17. In vitro tests to assess the effectiveness of tamarind (Tamarindus indicus) and oxalic acid solutions against cattle tick, Rhipicephalus (Boophilus) microplus

    OpenAIRE

    Álvarez C., Víctor

    2015-01-01

    An in vitro assay was performed to measure the acaricidal effectiveness of crude-extract of tamarind (Tamarindus indicus) to control the engorged female cattle tick (Rhipicephalus microplus). In addition, a product formulated with oxalic acid (OA) was tested. Parameters measured were percentage of oviposition inhibition and control rate. The best result was obtained with oxalic acid to twice the concentration recommended by the manufacturer for varroa control, followed by the tamarind pulp at...

  18. Applications in environmental bioinorganic: Nutritional and ultrastructural evaluation and calculus of thermodynamic and structural properties of metal-oxalate complexes.

    Science.gov (United States)

    Tolentino, Terezinha Alves; Bertoli, Alexandre Carvalho; dos Santos Pires, Maíra; Carvalho, Ruy; Labory, Claudia Regina Gontijo; Nunes, Janaira Santana; Bastos, Ana Rosa Ribeiro; de Freitas, Matheus Puggina

    2015-01-01

    Lead (Pb) is known by its toxicity both for animals and plants. In order to evaluate its toxicity, plants of Brachiaria brizantha were cultivated on nutritive solution of Hoagland during 90 days and submitted to different concentrations of Pb. The content of macro and micronutrients was evaluated and there was a reduction on root content of Ca, besides the lowest dosages of Pb had induced an increase of N, S, Mn, Cu, Zn and Fe. The cell ultrastructure of leaves and roots were analyzed by transmission electronic microscopy (TEM). Among the main alterations occurred there were invaginations on cell walls, the presence of crystals on the root cells, accumulation of material on the interior of cells and vacuolar compartmentalization. On the leaves the degradation of chloroplasts was observed, as well as the increase of vacuoles. Structures for the formation of oxalate crystals were proposed through molecular modeling and thermodynamic stability. Calculi suggest the formation of highly stable metal-oxalate complexes.

  19. Beta-alanine-oxalic acid (1:1) hemihydrate crystal: structure, 13C NMR and vibrational properties, protonation character.

    Science.gov (United States)

    Godzisz, D; Ilczyszyn, M; Ilczyszyn, M M

    2003-03-01

    The crystal structure of beta-alanine-oxalic acid (1:1) hemihydrate complex has been reinvestigated by X-ray diffraction method at 293 K. Formation of monoclinic crystal system belonging to C2/c space group and consisting of semi-oxalate chains, diprotonated beta-alanine dimers and water molecules bonded to both these units is confirmed. New results are obtained for distances in the carboxylic groups and hydrogen bonds. These structural observations are used for protonation degree monitoring on the carboxylic oxygen atoms. They are in accordance with our vibrational study. The 13C NMR spectra provide insights into the solid structure of this complex, character of its hydrogen bonds and the beta-alanine protonation.

  20. Genetic Mutation of Vitamin K-dependent Gamma-glutamyl Car-boxylase Domain in Patients with Calcium Oxalate Urolithiasis

    Institute of Scientific and Technical Information of China (English)

    Jiankun QIAO; Tao WANG; Jun YANG; Jihong LIU; Xiaoxin GONG; Xiaolin GUO; Shaogang WANG; Zhangqun YE

    2009-01-01

    To investigate the exon mutation of vitamin K-dependent gamma-glutamyl carboxylase (GGCX or VKDC) in patients with calcium oxalate urolithasis, renal cortex and peripheral blood sam-ples were obtained from severe hydronephrosis patients (with or without calculi), and renal tumor pa-tients undergoing nephrectomy. GGCX mutations in all 15 exons were examined in 44 patients with calcium oxalate urolithiasis (COU) by polymerase chain reaction (PCR) and denatured high pressure liquid chromatography (DHPLC), and confirmed by sequencing. Mutation was not found in all COU samples compared to the controls. These data demonstrated that functional GGCX mutations in all 15 exons do not occur in most COU patients. It was suggested that there may be no significant association between the low activity and mutation of GGCX in COU.