Synthesis of unsymmetrical dimethylhydrazine oxalate from rejected liquid rocket propellant

Science.gov (United States)

Mu, Xiaogang; Yang, Jingjing; Zhang, Youzhi

2018-02-01

The rejected liquid propellant unsymmetrical dimethylhydrazine (UDMH) was converted to UDMH oxalate, which has commercial value. The UDMH oxalate structure and stability were investigated by the Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and ultraviolet-visible spectrophotometric analysis. The results indicate that UDMH oxalate has good thermal and aqueous solution stability, a melting point of 144 °C, an initial decomposition temperature of 180 °C, and a peak wavelength of UV in aqueous solution at λ = 204 nm. This disposal method of rejected UDMH is highly efficient and environmentally safe.

Structural diversity of the lanthanide oxalates: Condensation of neodymium oxygen polyhedra under hydrothermal conditions

International Nuclear Information System (INIS)

Mer, A.; Rivenet, M.; Abraham, F.; De Almeida, L.; Grandjean, S.

2013-01-01

New neodymium hydroxo-oxalate and oxalate [Nd 6 (H 2 O) 6 (C 2 O 4 ) 7 (OH) 4 ].4H 2 O (1) and [Nd 2 (H 2 O) 4 (C 2 O 4 ) 3 ].2H 2 O (2) were synthesized by hydrothermal reaction at 150 C between neodymium nitrate and oxalic acid solutions at pH = 10-11 obtained by adding various monoamines. The structures were determined from single-crystal X-ray diffraction data. The two compounds crystallize in the monoclinic system with space group P21/c and a = 17.4384 (11), b = 8.1717 (5), c = 12.9929 (7), β = 94.66 (1) degrees, V = 1845.38 (19) (Angstroms) 3 , Z = 2 for 1 and a = 9.8249 (2) Angstroms, b = 8.2487 (2) Angstroms, c = 10.1911 (3) Angstroms, β = 99.09 (1), V = 815.53 (4) (Angstroms) 3 , Z = 2 for 2. Full matrix least-squares refinement yielded R1 = 0.0365 and 0.0267 for 6033 and 3382 independent reflections for 1 and 2 respectively. In 2, the three-dimensional neodymium oxalate arrangement results from dimeric units of edge shared NdO 9 polyhedra connected through oxalate ions acting as bis-bidentate. In 1, the neodymium atoms are connected through μ2-OH and μ3-OH ions to form a hexa-nuclear inorganic core [Nd 6 (OH) 4 (H 2 O) 6 ] with an un-precedently reported geometry leading to a hexa-nuclear polyhedra block. The blocks are connected through an O-O bridge involving two oxygen atoms of two oxalate ions to build a centipede-like ribbon. The ribbons are further connected through oxalate ions to form a three dimensional neodymium oxalate arrangement. In 1, oxalates adopt four distinct bridging modes of coordination, μ2, μ3, μ4 and μ5. (authors)

MRP-1 and BCRP Promote the Externalization of Phosphatidylserine in Oxalate-treated Renal Epithelial Cells: Implications for Calcium Oxalate Urolithiasis.

Science.gov (United States)

Li, YiFu; Yu, ShiLiang; Gan, XiuGuo; Zhang, Ze; Wang, Yan; Wang, YingWei; An, RuiHua

2017-09-01

To investigate the possible involvement of multidrug resistance-associated protein 1 (MRP-1) and breast cancer resistance protein (BCRP) in the oxalate-induced redistribution of phosphatidylserine (PS) in renal epithelial cell membranes. A western blot analysis was used to examine the MRP-1 and BCRP expression levels. Surface-expressed PS was detected by the annexin V-binding assay. The cell-permeable fluorogenic probe 2,7-dichlorofluorescein diacetate was used to measure the intracellular reactive oxygen species (ROS) level. A rat model of hyperoxaluria was obtained using 0.5% ethylene glycol and 1.0% ammonium chloride. In addition, certain animals received verapamil (50 mg/kg body weight), which is a common inhibitor of MRP-1 and BCRP. The degree of nephrolithiasis was assessed histomorphometrically using sections stained by Pizzolato method and by measuring the calcium oxalate crystal content in the renal tissue. Oxalate produced a concentration-dependent increase in the synthesis of MRP-1 and BCRP. Treatment with MK571 and Ko143 (MRP-1- and BCRP-specific inhibitors, respectively) significantly attenuated the oxalate-induced PS externalization. Adding the antioxidant N-acetyl-l-cysteine significantly reduced MRP-1 and BCRP expression. In vivo, markedly decreased nephrocalcinosis was observed compared with that in the rat model of hyperoxaluria without verapamil treatment. Oxalate induces the upregulation of MRP-1 and BCRP, which act as phospholipid floppases causing PS externalization in the renal epithelial cell membrane. The process is mediated by intracellular ROS production. The ROS-mediated increase in the synthesis of MRP-1 and BCRP can play an important role in hyperoxaluria-promoted calcium oxalate urolithiasis by facilitating phosphatidylserine redistribution in renal epithelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Study of interaction of bismuth, strontium, calcium copper, lead nitrates solutions with sodium oxalate solution with the aim of HTSC synthesis

International Nuclear Information System (INIS)

Danilov, V.P.; Krasnobaeva, O.N.; Nosova, T.A.

1993-01-01

With the aim of developing a new technique for HTSC oxides synthesis on the base of combined sedimentation of hydroxy salts and their heat treatment is studied interaction of bismuth, strontium, calcium, copper and lead nitrates with alkali solution of sodium oxalate. Conditions for total sedimentation of all five metals from the solution are found. The phase composition of interaction products is determined. It is established that they are high-dispersed homogeneous mixture of three phases of variable composition: twin hydroxalate of copper-bismuth, lead hydroxalate and twin oxalate of strontium-calcium. After heat treatment of the phases are obtained the HTSC oxides

Heterogeneous nucleation of calcium oxalate on native oxide surfaces

International Nuclear Information System (INIS)

Song, L.; Pattillo, M.J.; Graff, G.L.; Campbell, A.A.; Bunker, B.C.

1994-04-01

The aqueous deposition of calcium oxalate onto colloidal oxides has been studied as a model system for understanding heterogeneous nucleation processes of importance in biomimetic synthesis of ceramic thin films. Calcium oxalate nucleation has been monitored by measuring induction times for nucleation using Constant Composition techniques and by measuring nucleation densities on extended oxide surfaces using an atomic force microscope. Results show that the dependence of calcium oxalate nucleation on solution supersaturation fits the functional form predicted by classical nucleation theories. Anionic surfaces appear to promote nucleation better than cationic surfaces, lowering the effective energy barrier to heterogeneous nucleation

Structure of the oxalate-ATP complex with pyruvate kinase: ATP as a bridging ligand for the two divalent cations

International Nuclear Information System (INIS)

Lodato, D.T.; Reed, G.H.

1987-01-01

The 2 equiv of divalent cation that are required cofactors for pyruvate kinase reside in sites of different affinities for different species of cation. The intrinsic selectivity of the protein-based site for Mn(II) and of the nucleotide-based site for Mg(II) has been exploited in electron paramagnetic resonance (EOR) investigations of ligands for Mn(II) at the protein-based site. Oxalate, a structural analogue of the enolate of pyruvate, has been used as a surrogate for the reactive form of pyruvate in complexes with enzyme, Mn(II), Mg(II), and ATP. Superhyperfine coupling between the unpaired electron spin of Mn(II) and the nuclear spin of 17 O, specifically incorporated into oxalate, shows that oxalate is bound at the active site as a bidentate chelate with Mn(II). Coordination of the γ-phosphate of ATP to this same Mn(II) center is revealed by observation of superhyperfine coupling from 17 O regiospecifically incorporated into the γ-phosphate group of ATP. By contrast, 17 O in the α-phosphate or in the β-phosphate groups of ATP does not influence the spectrum. Experiments in 17 O-enriched water show that there is also a single water ligand bound to the Mn(II). These data indicate that ATP bridges Mn(II) and Mg(II) at the active site. A close spacing of the two divalent cations is also evident from the occurrence of magnetic interactions for complexes in which 2 equiv of Mn(II) are present at the active site. The structure for the enzyme-Mn(II)-oxalate-Mg(II)-ATP complex suggests a scheme for the normal reverse reaction of pyruvate kinase in which the divalent cation at the protein-based site activates the keto acid substrate through chelation and promotes phospho transfer by simultaneous coordination to the enolate oxygen and to a pendant oxygen from the γ-phosphate of ATP

Pseudomonas fluorescens ATCC 13525 Containing an Artificial Oxalate Operon and Vitreoscilla Hemoglobin Secretes Oxalic Acid and Solubilizes Rock Phosphate in Acidic Alfisols

Science.gov (United States)

Archana, G.; Naresh Kumar, G.

2014-01-01

Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah), Fomitopsis plaustris oxalate transporter (FpOAR) and Vitreoscilla hemoglobin (vgb) in various combinations. Pf (pKCN2) transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4) secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2) transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2) containing artificial oxalate operon (plac-FpOAR-oah) and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp) secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil. PMID:24705024

Pseudomonas fluorescens ATCC 13525 containing an artificial oxalate operon and Vitreoscilla hemoglobin secretes oxalic acid and solubilizes rock phosphate in acidic alfisols.

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Kavita Yadav

Full Text Available Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah, Fomitopsis plaustris oxalate transporter (FpOAR and Vitreoscilla hemoglobin (vgb in various combinations. Pf (pKCN2 transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4 secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2 transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2 containing artificial oxalate operon (plac-FpOAR-oah and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil.

Evaluation of oxalate decarboxylase and oxalate oxidase for industrial applications.

Science.gov (United States)

Cassland, Pierre; Sjöde, Anders; Winestrand, Sandra; Jönsson, Leif J; Nilvebrant, Nils-Olof

2010-05-01

Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley oxalate oxidase. Ten different filtrates from chemical pulping were selected for the evaluation. Oxalate decarboxylase degraded oxalic acid faster than oxalate oxidase in eight of the filtrates, while oxalate oxidase performed better in one filtrate. One of the filtrates inhibited both enzymes. The potential inhibitory effect of selected compounds on the enzymatic activity was tested. Oxalate decarboxylase was more sensitive than oxalate oxidase to hydrogen peroxide. Oxalate decarboxylase was not as sensitive to chlorate and chlorite as oxalate oxidase. Up to 4 mM chlorate ions, the highest concentration tested, had no inhibitory effect on oxalate decarboxylase. Analysis of the filtrates suggests that high concentrations of chlorate present in some of the filtrates were responsible for the higher sensitivity of oxalate oxidase in these filtrates. Oxalate decarboxylase was thus a better choice than oxalate oxidase for treatment of filtrates from chlorine dioxide bleaching.

Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

International Nuclear Information System (INIS)

Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

1988-01-01

Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14 CO 2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle

Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

1988-03-01

Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added /sup 14/CO/sub 2/ was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.

Morphological control of strontium oxalate particles by PSMA-mediated precipitation reaction

Energy Technology Data Exchange (ETDEWEB)

Yu Jiaguo [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)]. E-mail: jiaguoyu@yahoo.com; Tang Hua [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Cheng Bei [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2005-05-15

In this paper, strontium oxalate particles with different morphologies could be easily obtained by a precipitation reaction of sodium oxalate with strontium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA). The as-prepared products were characterized with scanning electron microscopy and X-ray diffraction. The effects of pH, aging time and concentration of PSMA on the phase structures and morphologies of the as-prepared strontium oxalate particles were investigated and discussed. The results showed that strontium oxalate particles with various morphologies, such as, bi-pyramids, rods, peanuts, and spherical particles, etc., could be obtained by varying the experimental conditions. PSMA promoted the formation of strontium oxalate dihydrate (SOD) phase. Suitable pH values (pH 7 and 8) favor the formation of the peanut-shaped SrC{sub 2}O{sub 4} particles. This research may provide new insight into the control of morphologies and phase structures of strontium oxalate particles and the biomimetic synthesis of novel inorganic materials.

Microbial growth on oxalate by a route not involving glyoxylate carboligase

Science.gov (United States)

Blackmore, Maureen A.; Quayle, J. R.

1970-01-01

1. The metabolism of oxalate by the pink-pigmented organisms, Pseudomonas AM1, Pseudomonas AM2, Protaminobacter ruber and Pseudomonas extorquens has been compared with that of the non-pigmented Pseudomonas oxalaticus. 2. During growth on oxalate, all the organisms contain oxalyl-CoA decarboxylase, formate dehydrogenase and oxalyl-CoA reductase. This is consistent with oxidation of oxalate to carbon dioxide taking place via oxalyl-CoA, formyl-CoA and formate as intermediates, and also reduction of oxalate to glyoxylate taking place via oxalyl-CoA. 3. The pink-pigmented organisms, when grown on oxalate, contain l-serine–glyoxylate aminotransferase and hydroxypyruvate reductase but do not contain glyoxylate carboligase. The converse of this obtains in oxalate-grown Ps. oxalaticus. This indicates that, in contrast with Ps. oxalaticus, synthesis of C3 compounds from oxalate by the pink-pigmented organisms occurs by a variant of the `serine pathway' used by Pseudomonas AM1 during growth on C1 compounds. 4. Evidence in favour of this scheme is provided by the finding that a mutant of Pseudomonas AM1 that lacks hydroxypyruvate reductase is not able to grow on oxalate. PMID:5472155

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

Investigation of composition and properties of some neptunium (5) oxalate compounds

International Nuclear Information System (INIS)

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

1981-01-01

A simple way of neptunium (5) oxalate synthesis is described and its composition is determined: (NpO 2 ) 2 C 2 O 4 xH 2 O. The compound is precipitated from solution during pouring together stoichiometric quantities of neptunium (5) nitrate and ammonium, sodium or potassium oxalate at pH=4-5. An explanation to unusual effect of solubility change with time of neptunium (5) monooxalate complexes and alkali metal or ammonium ion is found taking into account the slow formation of precipitate and low solubility of the compound obtained (0.62 g/l as to metal). Thermal decomposition of the compound is studied. At 180 deg C a water molecule is split off and at 260 deg C decomposition of neptunium oxalate starts. IR spectra and interplane distances (dsub(hkl)) of the compound crystal lattice are determined. New data on the synthesis and properties of complex neptunium (5) oxalates and monovalent cation in second sphere with the ratio ligand: metal=2:1 and 3:1 are presented. On the basis of results of IR spectroscopy and X-ray phase analyses a supposition is made on the existence of such complex compounds [ru

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

OpenAIRE

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

2015-01-01

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 ox...

Estimation of the oxalate content of foods and daily oxalate intake

Science.gov (United States)

Holmes, R. P.; Kennedy, M.

2000-01-01

BACKGROUND: The amount of oxalate ingested may be an important risk factor in the development of idiopathic calcium oxalate nephrolithiasis. Reliable food tables listing the oxalate content of foods are currently not available. The aim of this research was to develop an accurate and reliable method to measure the food content of oxalate. METHODS: Capillary electrophoresis (CE) and ion chromatography (IC) were compared as direct techniques for the estimation of the oxalate content of foods. Foods were thoroughly homogenized in acid, heat extracted, and clarified by centrifugation and filtration before dilution in water for analysis. Five individuals consuming self-selected diets maintained food records for three days to determine their mean daily oxalate intakes. RESULTS: Both techniques were capable of adequately measuring the oxalate in foods with a significant oxalate content. With foods of very low oxalate content (choice over IC for estimating the oxalate content of foods with a medium (>10 mg/100 g) to high oxalate content due to a faster analysis time and lower running costs, whereas IC may be better suited for the analysis of foods with a low oxalate content. Accurate estimates of the oxalate content of foods should permit the role of dietary oxalate in urinary oxalate excretion and stone formation to be clarified. Other factors, apart from the amount of oxalate ingested, appear to exert a major influence over the amount of oxalate excreted in the urine.

Role of cellular oxalate in oxalate clearance of patients with calcium oxalate monohydrate stone formation and normal controls.

Science.gov (United States)

Oehlschläger, Sven; Fuessel, Susanne; Meye, Axel; Herrmann, Jana; Froehner, Michael; Albrecht, Steffen; Wirth, Manfred P

2009-03-01

To examine the cellular, plasma, and urinary oxalate and erythrocyte oxalate flux in patients with calcium oxalate monohydrate (COM) stone formation vs normal controls. Pathologic oxalate clearance in humans is mostly integrated in calcium oxalate stone formation. An underlying cause of deficient oxalate clearance could be defective transmembrane oxalate transport, which, in many tissues, is regulated by an anion exchanger (SLC26). We studied 2 groups: 40 normal controls and 41 patients with COM stone formation. Red blood cells were divided for cellular oxalate measurement and for resuspension in a buffered solution (pH 7.40); 0.1 mmol/L oxalate was added. The supernatant was measured for oxalate immediately and 1 hour after incubation. The plasma and urinary oxalate were analyzed in parallel. The mean cellular oxalate concentrations were significantly greater in the normal controls (5.25 +/- 0.47 micromol/L) than in those with COM stone formation (2.36 +/- 0.28 micromol/L; P stone formation (0.31 +/- 0.02 mmol/L) than in the controls (0.24 +/- 0.02 mmol/L; P r = 0.49-0.63; P r = -0.29-0.41; P r = -0.30; P r = 0.25; P stone formation. Our data implicate the presence of a cellular oxalate buffer to stabilize plasma and urinary oxalate concentrations in normal controls.

Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

International Nuclear Information System (INIS)

Shi, Fa-Nian; Ananias, Duarte; Yang, Ting-Hai; Rocha, João

2013-01-01

A novel metal organic framework (MOF) formulated as [Eu(H 2 O) 2 (fdc)(ox) 0.5 ·(H 2 O)] n (1, fdc 2− =2,5-furandicarboxylate, ox 2− =oxalate), was hydrothermally synthesized via in situ ox 2− generation from the partial decomposition of the fdc 2− ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H 2 O, ox 2− and fdc 2− ) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu 3+ red emission and the differences observed reflects the slightly different structures of these polymorphs. - Graphical abstract: Exploring metal organic framework polymorphism in the system Eu(H 2 O) 2 (fdc)(ox) 0.5 ·(H 2 O)] n (fdc 2− =2,5-furandicarboxylate, ox 2− =oxalate) for tuning light emission. Display Omitted - Highlights: • Synthesis of Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOF polymorphs. • Detailed single-crystal study of polymorphs including hydrogen-bonding networks. • Photoluminescence spectroscopy show subtle differences light emission properties

Plasma oxalic acid and calcium levels in oxalate poisoning

Science.gov (United States)

Zarembski, P. M.; Hodgkinson, A.

1967-01-01

Observations are reported on five cases of suicide or attempted suicide by poisoning with oxalic acid or ethylene glycol. Elevated oxalic acid levels were observed in the plasma, stomach contents, and a number of tissues. Raised oxalic acid levels in plasma were associated with reduced total and ultrafilterable calcium levels. It is suggested that the reduction in plasma total calcium level is due mainly to the deposition of calcium oxalate in the soft tissues, but inhibition of the parathyroid glands may be a contributory factor. Microscopic examination of various tissues indicated that oxalic acid is deposited in the tissues in two forms: (1) crystalline calcium oxalate dihydrate in the kidney and (2) a non-crystalline complex of calcium oxalate and lipid in liver and other tissues. PMID:5602563

Synthesis from zinc oxalate, growth mechanism and optical properties of ZnO nano/micro structures

Energy Technology Data Exchange (ETDEWEB)

Raj, C. Justin; Varma, K.B.R. [Materials Research Centre, Indian Institute of Science, Bangalore 560 012 (India); Joshi, R.K. [Special Center for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)

2011-11-15

We report the synthesis of various morphological micro to nano structured zinc oxide crystals via simple precipitation technique. The growth mechanisms of the zinc oxide nanostructures such as snowflake, rose, platelets, porous pyramid and rectangular shapes were studied in detail under various growth conditions. The precursor powders were prepared using several zinc counter ions such as chloride, nitrate and sulphate along with oxalic acid as a precipitating agent. The precursors were decomposed by heating in air resulting in the formation of different shapes of zinc oxide crystals. Variations in ZnO nanostructural shapes were possibly due to the counter ion effect. Sulphate counter ion led to unusual rose-shape morphology. Strong ultrasonic treatment on ZnO rose shows that it was formed by irregular arrangement of micro to nano size hexagonal zinc oxide platelets. The X-ray diffraction studies confirmed the wurzite structure of all zinc oxide samples synthesized using different zinc counter ions. Functional groups of the zinc oxalate precursor and zinc oxide were identified using micro Raman studies. The blue light emission spectra of the various morphologies were recorded using luminescence spectrometer. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Hydrothermal growth of cross-linked hyperbranched copper dendrites using copper oxalate complex

Science.gov (United States)

Truong, Quang Duc; Kakihana, Masato

2012-06-01

A facile and surfactant-free approach has been developed for the synthesis of cross-linked hyperbranched copper dendrites using copper oxalate complex as a precursor and oxalic acid as a reducing and structure-directing agent. The synthesized particles are composed of highly branched nanostructures with unusual cross-linked hierarchical networks. The formation of copper dendrites can be explained in view of both diffusion control and aggregation-based growth model accompanied by the chelation-assisted assembly. Oxalic acid was found to play dual roles as reducing and structure-directing agent based on the investigation results. The understanding on the crystal growth and the roles of oxalic acid provides clear insight into the formation mechanism of hyperbranched metal dendrites.

Hydrothermal synthesis of two layered indium oxalates with 12-membered apertures

International Nuclear Information System (INIS)

Chen Zhenxia; Zhou Yaming; Weng Linhong; Zhang Haoyu; Zhao Dongyuan

2003-01-01

Two layered indium oxalates, In(C 2 O 4 ) 2.5 (C 3 N 2 H 12 )(H 2 O) 3 , I, and In(C 2 O 4 ) 1.5 (H 2 O) 3 , II, have been hydrothermally synthesized. In I, the linkage between indium and oxalate units gives rise to a sheet with a rectangular 12-membered aperture (six indium atoms and six oxalate units). Indium atom of II has an unusual pentagonal bipyramidal coordination arrangement. The connectivity between indium and oxalate units forms a neutral puckered layer with 12- (along a-axis) and eight-membered (along b-axis) apertures. Crystal data for these two indium oxalates are as follows: I, triclinic, space group: P-1 (No. 2), a=8.725(3) A, b=9.170(3) A, c=9.901(3) A, α=98.101(4) deg. , β=97.068(4) deg. , γ=102.403(4) deg. , V=756.3(4) A 3 , Z=2, M=463.0(5), ρ calc =2.042 g/cm 3 , R 1 =0.0377, wR 2 =0.0834. II, monoclinic, space group: P2 1 /c (No. 14), a=10.203(5) A, b=6.638(1) A, c=11.152(7) A, β=95.649(4) deg. , V=751.7(4)A 3 , Z=4, M=300.9(0), ρ calc =2.659 g/cm 3 , R 1 =0.0229, wR 2 =0.0488. TG analyses indicate the water molecules of I can be removed at 150 deg. C. The dehydrated product retains structural integrity

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.

Neptunium (IV) oxalate solubility

International Nuclear Information System (INIS)

Luerkens, D.W.

1983-07-01

The equilibrium solubility of neptunium (IV) oxalate in nitric/oxalic acid solutions was determined at 22 0 C, 45 0 C, and 60 0 C. The concentrations of nitric/oxalic acid solutions represented a wide range of free oxalate ion concentration. A mathematical solubility model was developed which is based on the formation of the known complexes of neptunium (IV) oxalate. the solubility model uses a simplified concentration parameter which is proportional to the free oxalate ion concentration. The solubility model can be used to estimate the equilibrium solubility of neptunium (IV) oxalate over a wide range of oxalic and nitric acid concentrations at each temperature

Hygroscopic properties of oxalic acid and atmospherically relevant oxalates

Science.gov (United States)

Ma, Qingxin; He, Hong; Liu, Chang

2013-04-01

Oxalic acid and oxalates represent an important fraction of atmospheric organic aerosols, however, little knowledge about the hygroscopic behavior of these particles is known. In this study, the hygroscopic behavior of oxalic acid and atmospherically relevant oxalates (H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4) were studied by Raman spectrometry and vapor sorption analyzer. Under ambient relative humidity (RH) of 10-90%, oxalic acid and these oxalates hardly deliquesce and exhibit low hygroscopicity, however, transformation between anhydrous and hydrated particles was observed during the humidifying and dehumidifying processes. During the water adsorption process, conversion of anhydrous H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4 to their hydrated particles (i.e., H2C2O4·2H2O, (NH4)2C2O4·H2O, CaC2O4·H2O, and FeC2O4·2H2O) occurred at about 20% RH, 55% RH, 10% RH, and 75% RH, respectively. Uptake of water on hydrated Ca-oxalate and Fe-oxalate particles can be described by a multilayer adsorption isotherm. During the dehumidifying process, dehydration of H2C2O4·2H2O and (NH4)2C2O4·H2O occurred at 5% RH while CaC2O4·H2O and FeC2O4·2H2O did not undergo dehydration. These results implied that hydrated particles represent the most stable state of oxalic acid and oxalates in the atmosphere. In addition, the assignments of Raman shift bands in the range of 1610-1650 cm-1 were discussed according to the hygroscopic behavior measurement results.

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.

Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the ?-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

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

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.

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

Enhanced nitrogen availability in karst ecosystems by oxalic acid release in the rhizosphere

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Fujing ePan

2016-05-01

Full Text Available In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM and causes nitrogen (N and/or phosphorus (P limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015 where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass C (MBC, and β-1,4-N-acetylglucosaminidase (NAG on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems.

Electrolytic destruction of oxalate ions in plutonium oxalate supernatant

International Nuclear Information System (INIS)

Michael, K.M.; Talnikar, S.G.; Jambunathan, U.; Kapoor, S.C.; Ramanujam, A.; Venkataraman, N.

1996-01-01

A simple and efficient electrolytic method is described for the destruction of the oxalate ions present in plutonium oxalate supernatant. Using platinum electrode and very little KMnO 4 , in situ generation of Mn 3+ ions is achieved which in turn destroys the oxalate. The use of lower current density helps in achieving maximum current efficiency. The end point is easily detectable by the pink colour of permanganate. By reversing the current, this slight excess of permanganate can be destroyed, thus avoiding the use of hydrogen peroxide. By this simple electrolytic method, the corrosive oxalate ion is completely destroyed and the salt content of the waste solution is considerably reduced. (author). 4 refs., 1 fig., 6 tabs

Destruction of oxalate by reaction with hydrogen peroxide. [Hydrazine oxalate

Energy Technology Data Exchange (ETDEWEB)

Mailen, J.C.; Tallent, O.K.; Arwood, P.C.

1981-09-01

The destruction of oxalate by oxidation to carbon dioxide using hydrogen peroxide was studied as an alternative method for the disposal of oxalate in connection with the possible use of an aqueous hydrazine oxalate solution as a scrubbing agent for solvent cleanup in processes for the recovery of uranium, plutonium, and thorium by solvent extraction. The rate of oxidation of oxalate by hydrogen peroxide in acid solution at the reflux temperature was adequate for process application; reaction half-times at 100/sup 0/C were less than one hour when the hydrogen peroxide concentration was greater than 0.5 M. The reaction was first order with respect to both the oxalate and hydrogen peroxide concentrations and had an activation energy of 58.7 kJ/g-mol. The rate increased with the hydrogen ion concentration as (H/sup +/)/sup 0/ /sup 3/ but was not significantly affected by the presence of 100 ppM of uranium or copper in solution. In the near-neutral hydrazine oxalate solutions, the reaction of either component with hydrogen peroxide was too slow for process application.

On the americium oxalate solubility

International Nuclear Information System (INIS)

Zakolupin, S.A.; Korablin, Eh.V.

1977-01-01

The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

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

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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.

Biosynthesis of l-Ascorbic Acid and Conversion of Carbons 1 and 2 of l-Ascorbic Acid to Oxalic Acid Occurs within Individual Calcium Oxalate Crystal Idioblasts1

Science.gov (United States)

Kostman, Todd A.; Tarlyn, Nathan M.; Loewus, Frank A.; Franceschi, Vincent R.

2001-01-01

l-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various 14C-labeled compounds and examined by micro-autoradiography for incorporation of 14C into calcium oxalate crystals. [14C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-14C]AsA also gave heavy labeling of crystals, whereas [6-14C]AsA gave no labeling. Labeled precursors of AsA (l-[1-14C]galactose; d-[1-14C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, d-[1-14C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > l-galactose > d-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via d-mannose and l-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments. PMID:11161021

Thorium oxalate solubility and morphology

International Nuclear Information System (INIS)

Monson, P.R. Jr.; Hall, R.

1981-10-01

Thorium was used as a stand-in for studying the solubility and precipitation of neptunium and plutonium oxalates. Thorium oxalate solubility was determined over a range of 0.001 to 10.0 in the concentration parameter [H 2 C 2 O 4 ]/[HNO 3 ] 2 . Morphology of thorium oxide made from the oxalate precipitates was characterized by scanning electron microscopy. The different morphologies found for oxalate-lean and oxalate-rich precipitations were in agreement with predictions based on precipitation theory

Two- and three-dimensional lanthanide-organic frameworks constructed using 1-hydro-6-oxopyridine-3-carboxylate and oxalate ligands.

Science.gov (United States)

Liu, Cai-Ming; Xiong, Ming; Zhang, De-Qing; Du, Miao; Zhu, Dao-Ben

2009-08-07

6-Hydroxypyridine-3-carboxylic acid (6-HOPy-3-CO(2)H) reacts with Ln(2)O(3) (Ln = Nd, Sm, Eu, Gd) and oxalic acid (H(2)OX) under hydrothermal conditions to generate four novel lanthanide-organic coordination polymeric networks [Ln(2)(1H-6-Opy-3-CO(2))(2)(OX)(2)(H(2)O)(3)] x 2.5 H(2)O (Ln = Nd, 1; Sm, 2; 1H-6-Opy-3-CO(2)(-) = 1-hydro-6-oxopyridine-3-carboxylate) and [Ln(1H-6-Opy-3-CO(2))(OX)(H(2)O)(2)] x H(2)O (Ln = Eu, 3; Gd, 4). The new co-ligand 1H-6-Opy-3-CO(2)(-) anion was generated by the autoisomerization of the single deprotonated 6-HOPy-3-CO(2)(-) anion (from the enol form into the ketone one). 1 and 2 are isomorphous, they possess a three-dimensional architecture constructed from Ln(3+) ions bridged by oxalate anions and two types of 1H-6-Opy-3-CO(2)(-) bridges, showing a three-nodal (4,5)-connected topology (3.4(2).5(2).6(3).7.8)(2)(3.5(3).6(2))(2)(3(2).6.7(2).8) or a simplified uninodal 6-connected topology (3(3).4(6).5(5).6), both topologies are completely new; while only one type of 1H-6-Opy-3-CO(2)(-) bridge is used to construct the two-dimensional layer networks of 3 and 4 besides oxalate bridges, both complexes 3 and 4 are isostructural, exhibiting the honeycomb topology 6(3). The lanthanide contraction effect is believed to play a key role in directing the formation of a particular structure. A magnetic study of 1-3 indicated that the coupling interaction between Ln(3+) ions is weak.

Oxidation of ferrocene by thiocyanic acid in the presence of ammonium oxalate

Science.gov (United States)

Ruslin, Farah bt; Yamin, Bohari M.

2014-09-01

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.

Dissolution of oxalate precipitate and destruction of oxalate ion by hydrogen peroxide in nitric acid solution

International Nuclear Information System (INIS)

Kim, Eung-Ho; Chung, Dong-Yong; Park, Jin-Ho; Yoo, Jae-Hyung

2000-01-01

This study aims at developing an oxalate precipitation process, which is applicable to a partitioning of long-lived radionuclides from the high-level radioactive liquid waste. In order to achieve this, a study for decomposition-reaction of oxalic acid by hydrogen peroxide was first carried out. The decomposition rates of H 2 O 2 and oxalic acid increased with an increase of nitric acid concentration, and especially those decomposition rates steeply increased at more than 2 M HNO 3 . Based on this result, the decomposition kinetics of H 2 O 2 and oxalic acid were suggested in this work. Then, the dissolution of oxalate precipitate and the destruction of oxalate ion in the solution were examined. Oxalate precipitates were prepared by adding oxalic acid into a simulated radioactive waste containing 8 metallic elements. The precipitates obtained thereby were dissolved in various nitric acid concentrations and reacted with H 2 O 2 at 90degC. When the oxalates were completely dissolved, most of the oxalates were decomposed by adding H 2 O 2 , but in a slurry state the decomposition yield of the oxalate decreased with an increase of the slurry density in the solution. Such phenomenon was considered to be due to a catalytic decomposition of H 2 O 2 on a solid surface of oxalate and the decomposition mechanism was explained by a charge transfer from a surface of oxalate solid to H 2 O 2 , producing OH radicals which can destruct H 2 O 2 explosively. Accordingly, the experimental condition for the decomposition of the oxalate precipitates was found to be most favorable at 3 M HNO 3 under the initial concentrations of 0.2 M oxalate and 1 M H 2 O 2 . At 3M HNO 3 , oxalate precipitates could be safely and completely dissolved, and almost decomposed. Additionally, it was observed that the presence of ferric ion in the solution largely affects the decomposition rate of H 2 O 2 . This could be explained by a chain reaction of hydrogen peroxide with ferric ion in the solution

Vibrational studies in aqueous solutions. Part II. The acid oxalate ion and oxalic acid

Science.gov (United States)

Shippey, T. A.

1980-08-01

Assignments for oxalic acid in solution are re-examined. A detailed assignment of the IR and Raman spectra of the acid oxalate ion is presented for the first time. Raman spectroscopy is used to study the first ionization of oxalic acid.

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)

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

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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

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

  Oxalic acid (C2O4H2), the strongest of the organic acids is produced by both brown and white rot decay fungi and has been connected to various aspects of brown- and white rot decay including the Fenton reaction (Green and Highley, 1997; Munir et al.,2001). Oxalic acid is secreted into the wood...... 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...

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

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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

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

Science.gov (United States)

Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Leisner, T.

2010-08-01

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 that coating layers

Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants 1

Science.gov (United States)

Yang, Joan C.; Loewus, Frank A.

1975-01-01

l-Ascorbic acid-1-14C and its oxidation product, dehydro-l-ascorbic acid, produced labeled oxalic acid in oxalate-accumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and O. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In O. oregana, conversion occurred equally well in the presence or absence of light. This relationship between l-ascorbic acid metabolism and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants. PMID:16659288

Synthesis, structure and magnetic properties of a new iron phosphonate-oxalate with 3D framework: [Fe(O3PCH3)(C2O4)0.5(H2O)

International Nuclear Information System (INIS)

Zhang Yangyang; Qi Yue; Zhang Ying; Liu Ziyu; Zhao Yinfeng; Liu Zhongmin

2007-01-01

A new iron phosphonate-oxalate [Fe(O 3 PCH 3 )(C 2 O 4 ) 0.5 (H 2 O)] (1), has been synthesized under hydrothermal condition. The single-crystal X-ray diffraction studies reveal that 1 consists of layers of vertex-linked FeO 6 octahedra and O 3 PC tetrahedra, which are further connected by bis-chelate oxalate bridges, giving to a 3D structure with 10-membered channels. Crystal data: monoclinic, P2 1 /n (no. 14), a=4.851(2)A, b=16.803(7)A, c=7.941(4)A, β=107.516(6) o , V=617.2(5)A 3 , Z=4, R 1 =0.0337 and wR 2 =0.0874 for 1251 reflections [I>2σ(I)]. Mossbauer spectroscopy measurement confirms the existence of high-spin Fe(III) in 1. Magnetic studies show that 1 exhibits weak ferromagnetism with T N =30K due to a weak spin canting

Equilibrium aluminium hydroxo-oxalate phases during initial clay formation; H +-Al 3+-oxalic acid-Na + system

Science.gov (United States)

Bilinski, Halka; Horvath, Laszlo; Ingri, Nils; Sjöberg, Staffan

1986-09-01

The conditions necessary for initial clay formation have been studied in different model systems comprising different organic acids besides Si and Al. In the present paper the solid phases and the precipitation boundary characterizing the subsystem H +-Al 3+-oxalic acid (H 2L) are discussed. pH and tyndallometric measurements were performed in an ionic medium of 0.6 M Na(Cl) at 25 °C. The two phases Al 3(OH) 7(C 2O 4) · 3H 2O (phase I) and NaAl(OH) 2(C 2O 4) · 3H 2O (phase II) determine the precipitation boundary. The following formation constants for the two phases were deduced: lgβ1 = lg([ Al3+] -3[ H2C2O4] -1[ H+] 9 = -21.87 ± 0.08 and lgβ11 = lg([ Al3+] -1[ H2C2O4] -1[ H+] 4 = -5.61 ± 0.06. Phase I exists in the range [ Al] tot≥ 10 -4.4moldm-3,[ H2C2O4] tot ≥ 10 -4.9moldm-3 and at pH oxalic-rich natural waters. The more soluble sodium phase is unlikely to exist in natural waters. The two phases are metastable relative to crystalline gibbsite and may be considered as the first precipitation step in the transition from aqueous Al oxalates down to stable Al hydroxide. Model calculations illustrating these competing hydrolysis-complexation reactions are discussed in terms of predominance and speciation diagrams. The solid phases have been characterized by X-ray analysis of powders, TGA and IR spectra, and tentative structures are proposed. Phase I seems to be an octahedral layer structure, in which 3/5 of the octahedral sites between two close packed oxygen sheets are occupied by Al 3+ and the oxalate ion acts as a bridge ligand between two aluminium atoms. Phase II forms a more open sheet structure and has ion exchange properties. Powder data for a phase crystallized from the studied solution after a year are also presented. This phase, Na 4Al 2(OH) 2(C 2O 4) 4 · 10H 2O, supports the results from the equilibrium analysis of recent solution data by SJöBERG and ÖHMAN (1985), who have found the dinuclear complex Al 2(OH) 2(C 2O 4) 44- to exist in a

Oxalate: Effect on calcium absorbability

International Nuclear Information System (INIS)

Heaney, R.P.; Weaver, C.M.

1989-01-01

Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species

The bioavailability of oxalate from Oca (Oxalis tuberosa).

Science.gov (United States)

Albihn, P B; Savage, G P

2001-08-01

It is believed that soluble oxalate has higher bioavailability than insoluble oxalate. Oca (Oxalis tuberosa) is moderately high in oxalate and contains oxalate in soluble form only. We estimated the bioavailability of oxalate in oca based on the urinary excretion of oxalate after oxalate loading with oca to estimate the bioavailability of oxalate in oca. We also clarified whether bioavailability differs in various oxalate loads from the same food source and studied the effect of an additional calcium source on the bioavailability of oxalate from oca. Four men and 4 women ingested 50, 100 and 150 gm. oca as well as 100 gm. oca with 100 gm. sour cream. Oxalate was measured in a 6-hour urine sample from each volunteer. The mean bioavailability of oxalate from oca plus or minus standard deviation was 1.44% +/- 1.31% during the 6-hour period after intake. There was no significant difference in oxalate bioavailability among oxalate intake levels in this study, although oca consumption with sour cream significantly decreased the uptake of oxalate (p oca appears to be similar to that in spinach. However, bioavailability varies among individuals and depends on other constituents of a combined meal.

Calcium oxalate stone and gout.

Science.gov (United States)

Marickar, Y M Fazil

2009-12-01

Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P stones patients. The inhibitor urine citrate (P stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

Decomposition of oxalate precipitates by photochemical reaction

International Nuclear Information System (INIS)

Jae-Hyung Yoo; Eung-Ho Kim

1999-01-01

A photo-radiation method was applied to decompose oxalate precipitates so that it can be dissolved into dilute nitric acid. This work has been studied as a part of partitioning of minor actinides. Minor actinides can be recovered from high-level wastes as oxalate precipitates, but they tend to be coprecipitated together with lanthanide oxalates. This requires another partitioning step for mutual separation of actinide and lanthanide groups. In this study, therefore, some experimental work of photochemical decomposition of oxalate was carried out to prove its feasibility as a step of partitioning process. The decomposition of oxalic acid in the presence of nitric acid was performed in advance in order to understand the mechanistic behaviour of oxalate destruction, and then the decomposition of neodymium oxalate, which was chosen as a stand-in compound representing minor actinide and lanthanide oxalates, was examined. The decomposition rate of neodymium oxalate was found as 0.003 mole/hr at the conditions of 0.5 M HNO 3 and room temperature when a mercury lamp was used as a light source. (author)

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.

Morphology-controllable synthesis of cobalt oxalates and their conversion to mesoporous Co3O4 nanostructures for application in supercapacitors.

Science.gov (United States)

Wang, Dewei; Wang, Qihua; Wang, Tingmei

2011-07-18

In this work, one-dimensional and layered parallel folding of cobalt oxalate nanostructures have been selectively prepared by a one-step, template-free, water-controlled precipitation approach by simply altering the solvents used at ambient temperature and pressure. Encouragingly, the feeding order of solutions played an extraordinary role in the synthesis of nanorods and nanowires. After calcination in air, the as-prepared cobalt oxalate nanostructures were converted to mesoporous Co(3)O(4) nanostructures while their original frame structures were well maintained. The phase composition, morphology, and structure of the as-obtained products were studied in detail. Electrochemical properties of the Co(3)O(4) electrodes were carried out using cyclic voltammetry (CV) and galvanostatic charge-discharge measurements by a three-electrode system. The electrochemical experiments revealed that the layered parallel folding structure of mesoporous Co(3)O(4) exhibited higher capacitance compared to that of the nanorods and nanowires. A maximum specific capacitance of 202.5 F g (-1) has been obtained in 2 M KOH aqueous electrolyte at a current density of 1 A g(-1) with a voltage window from 0 to 0.40 V. Furthermore, the specific capacitance decay after 1000 continuous charge-discharge cycles was negligible, revealing the excellent stability of the electrode. These characteristics indicate that the mesoporous Co(3)O(4) nanostructures are promising electrode materials for supercapacitors.

Recovery Ce from Ce - TBP Used Oxalic Acid

International Nuclear Information System (INIS)

Purwani, MV; Subagiono, R.; Suyanti

2007-01-01

Recovery or stripping Ce from Ce - TBP product of monazite sand used oxalic acid. Ce - TBP as organic phase and oxalic acid as aqueous phase and as strong precipitant compound to precipitate metal element. The stripping product as Ce - oxalic precipitate. The influence parameter were percentage of oxalic acid, volume ratio of Ce-TBP with oxalic acid, time and rate of stripping. At stripping of 25 ml Ce - TBP used oxalic acid, the optimum condition were achieve at using 5% oxalic acid, volume ratio of Ce - TBP : 5% oxalic acid = 1 : 1, time of stripping 7.5 minute and rate of stripping 150 rpm. At the optimum condition was obtained the recovery efficiency was 100%. (author)

Reaction of uranyl nitrate with carboxylic di-acids under hydrothermal conditions. Crystal structure of complexes with L(+)-tartaric and oxalic acids

International Nuclear Information System (INIS)

Thuery, P.

2007-01-01

L(+)-tartaric acid reacts with uranyl nitrate in the presence of KOH, under mild hydrothermal conditions, to give the complex [UO 2 (C 4 H 4 O 6 )(H 2 O)] (1), the first uranyl tartrate to be crystallographically characterized. Each tartrate ligand bridges three uranyl ions, one of them in chelating fashion through proximal carboxylate and hydroxyl groups. The resulting assemblage is two-dimensional, with the uranyl pentagonal bipyramidal coordination polyhedra separated from one another. Prolonged heating of an uranyl tartrate solution resulted in oxidative cleavage of the acid and formation of the oxalate complex [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)Na(H 2 O) 2 ] (2). The bis-bidentate oxalate and bridging hydroxide groups ensure the formation of sheets with corner-sharing uranyl pentagonal bipyramidal coordination polyhedra, in which six-membered metallacycles encompass the sodium ions. These sheets are assembled into a three-dimensional framework through further oxo-bonding of the sodium ions. (authors)

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

OpenAIRE

R. Wagner; O. Möhler; H. Saathoff; M. Schnaiter; T. Leisner

2010-01-01

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 ...

The comparability of oxalate excretion and oxalate:creatinine ratio in the investigation of primary hyperoxaluria: review of data from a referral centre.

Science.gov (United States)

Clifford-Mobley, Oliver; Tims, Christopher; Rumsby, Gill

2015-01-01

Urine oxalate measurement is an important investigation in the evaluation of renal stone disease. Primary hyperoxaluria (PH) is a rare inherited metabolic disease characterised by persistently elevated urine oxalate, but the diagnosis may be missed in adults until renal failure has developed. Urine oxalate results were reviewed to compare oxalate:creatinine ratio and oxalate excretion, and to estimate the potential numbers of undiagnosed PH. Urine oxalate results from August 2011 to April 2013 were reviewed. Oxalate excretion and oxalate:creatinine ratio were evaluated for 24 h collections and ratio alone for spot urine samples. Oxalate:creatinine ratio and oxalate excretion were moderately correlated (R=0.63) in 24-h urine collections from patients aged 18 years and above. Sex-related differences were found requiring implementation of male and female reference ranges for oxalate:creatinine ratio. Of samples with both ratio and excretion above the reference range, 7% came from patients with confirmed PH. There were 24 patients with grossly elevated urine oxalate who had not been evaluated for PH. Oxalate:creatinine ratio and oxalate excretion were discordant in many patients, which is likely to be a result of intra-individual variation in creatinine output and imprecision in the collection itself. Some PH patients had urine oxalate within the reference range on occasion, and therefore it is not possible to exclude PH on the finding of a single normal result. A significant number of individuals had urine oxalate results well above the reference range who potentially have undiagnosed PH and are consequently at risk of renal failure. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Influence of oxalate ligand functionalization on Co/ZSM-5 activity in Fischer Tropsch synthesis and hydrodeoxygenation of oleic acid into hydrocarbon fuels.

Science.gov (United States)

Ayodele, Olumide Bolarinwa

2017-08-30

Achieving high degree of active metal dispersions at the highest possible metal loading and high reducibility of the metal remains a challenge in Fischer Tropsch synthesis (FTS) as well as in hydrogeoxygenation (HDO).This study therefore reports the influence of oxalic acid (OxA) functionalization on the metal dispersion, reducibility and activity of Co supported ZSM-5 catalyst in FTS and HDO of oleic acid into paraffin biofuel. The Brunauer-Emmett-Teller (BET) results showed that cobalt oxalate supported ZSM-5 catalyst (CoOx/ZSM-5) synthesized from the incorporation of freshly prepared cobalt oxalate complex into ZSM-5 displayed increase in surface area, pore volume and average pore size while the nonfunctionalized cobalt supported on ZSM-5 (Co/ZSM-5) catalyst showed reduction in those properties. Furthermore, both XRD and XPS confirmed the presence of Co° formed from the decomposition of CoOx during calcination of CoOx/ZSM-5 under inert atmosphere. The HRTEM showed that Co species average particle sizes were smaller in CoOx/ZSM-5 than in Co/ZSM-5, and in addition, CoOx/ZSM-5 shows a clear higher degree of active metal dispersion. The FTS result showed that at CO conversion over Co/ZSM-5 and CoOx/ZSM-5 catalysts were 74.28% and 94.23% and their selectivity to C 5+ HC production were 63.15% and 75.4%, respectively at 4 h TOS. The HDO result also showed that the CoOx/ZSM-5 has higher OA conversion of 92% compared to 59% over Co/ZSM-5. In addition CoOx/ZSM-5 showed higher HDO and isomerization activities compared to Co/ZSM-5.

De-agglomeration of thorium oxalate - a method for the synthesis of sinteractive thoria

International Nuclear Information System (INIS)

Ananthasivan, K.; Anthonysamy, S.; Singh, Alok; Vasudeva Rao, P.R.

2002-01-01

Thorium oxalate was obtained by precipitation in water and in non-aqueous solvents and de-agglomerated by ultrasonication in both aqueous as well as non-aqueous media. Sinteractive thoria (crystallite size 6-20 nm) obtained from the de-agglomerated thorium oxalate was characterised for residual carbon, crystallite size, specific surface area, particle size distribution and bulk density. Microstructure of the precursor and the product was studied using TEM and HRTEM. The morphology of the sintered pellets was studied using SEM. The reactivity of the calcined powders was determined by measuring the density of the sintered compacts. The solvent used for de-agglomeration was found to have significant influence on the microstructure of the powders. Thoria derived through aqueous precipitation route could be sintered to a density of 9.7 Mg m -3 at 1673 K. It was demonstrated that ultrasonic de-agglomeration could be a useful method for obtaining sinteractive thoria

Synthesis of CaTiO 3 from calcium titanyl oxalate hexahydrate (CTO)

Indian Academy of Sciences (India)

Calcium titanate, CaTiO3, an important microwave dielectric material and one of major phases in synroc (synthetic rock), a titanate ceramic with potential application for fixation of high level nuclear waste was synthesized from calcium titanyl oxalate [CaTiO (C2O4)2.6H2O] (CTO) by employing microwave heating technique.

Decomposition of oxalate precipitates by photochemical reaction

International Nuclear Information System (INIS)

Yoo, J.H.; Kim, E.H.

1998-01-01

A photo-radiation method was applied to decompose oxalate precipitates so that it can be dissolved into dilute nitric acid. This work has been studied as a part of partitioning of minor actinides. Minor actinides can be recovered from high-level wastes as oxalate precipitates, but they tend to be coprecipitated together with lanthanide oxalates. This requires another partitioning step for mutual separation of actinide and lanthanide groups. In this study, therefore, the photochemical decomposition mechanism of oxalates in the presence of nitric acid was elucidated by experimental work. The decomposition of oxalates was proved to be dominated by the reaction with hydroxyl radical generated from the nitric acid, rather than with nitrite ion also formed from nitrate ion. The decomposition rate of neodymium oxalate, which was chosen as a stand-in compound representing minor actinide and lanthanide oxalates, was found to be 0.003 M/hr at the conditions of 0.5 M HNO 3 and room temperature when a mercury lamp was used as a light source. (author)

Co-precipitation of plutonium(IV) and americium(III) from nitric acid-oxalic acid solutions with bismuth oxalate

International Nuclear Information System (INIS)

Pius, I.C.; Noronha, D.M.; Chaudhury, Satyajeet

2017-01-01

Co-precipitation of plutonium and americium from nitric acid-oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from waste solutions. Effect of concentration of bismuth and oxalic acid on the co-precipitation of Pu(IV) from 3 M HNO_3 has been investigated. Similar experiments were also carried out from 3.75 M HNO_3 on co-precipitation of Am(III) to optimize the conditions of precipitation. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate indicate feasibility of treatment of plutonium and americium bearing waste solutions. (author)

Oxalates in oca (New Zealand yam) (Oxalis tuberosa Mol.).

Science.gov (United States)

Ross, A B; Savage, G P; Martin, R J; Vanhanen, L

1999-12-01

Oca (Oxalis tuberosa Mol.) or New Zealand yam, in common with other members of this genus, contains oxalate, an antinutritive factor. Twelve South American and two New Zealand cultivars of oca were analyzed for total and soluble oxalate contents of the tubers. The range of total oxalate levels was 92-221 mg/100 g of fresh weight. Levels of soluble and total oxalate extracted from the tubers were not significantly different, suggesting that no calcium oxalate is formed in the tubers. The oxalate concentrations obtained in this study for oca suggest that previously reported values are too low and that oca is a moderately high oxalate-containing food. This is the first report of a tuber crop containing moderate to high levels of soluble oxalates in the tubers and no insoluble oxalates.

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].

Isolation of oxalic acid tolerating fungi and decipherization of its potential to control Sclerotinia sclerotiorum through oxalate oxidase like protein.

Science.gov (United States)

Yadav, Shivani; Srivastava, Alok K; Singh, Dhanajay P; Arora, Dilip K

2012-11-01

Oxalic acid plays major role in the pathogenesis by Sclerotinia sclerotiorum; it lowers the pH of nearby environment and creates the favorable condition for the infection. In this study we examined the degradation of oxalic acid through oxalate oxidase and biocontrol of Sclerotinia sclerotiorum. A survey was conducted to collect the rhizospheric soil samples from Indo-Gangetic Plains of India to isolate the efficient fungal strains able to tolerate oxalic acid. A total of 120 fungal strains were isolated from root adhering soils of different vegetable crops. Out of 120 strains a total of 80 isolates were able to grow at 10 mM of oxalic acid whereas only 15 isolates were grow at 50 mM of oxalic acid concentration. Then we examined the antagonistic activity of the 15 isolates against Sclerotinia sclerotiorum. These strains potentially inhibit the growth of the test pathogen. A total of three potential strains and two standard cultures of fungi were tested for the oxalate oxidase activity. Strains S7 showed the maximum degradation of oxalic acid (23 %) after 60 min of incubation with fungal extract having oxalate oxidase activity. Microscopic observation and ITS (internally transcribed spacers) sequencing categorized the potential fungal strains into the Aspergillus, Fusarium and Trichoderma. Trichoderma sp. are well studied biocontrol agent and interestingly we also found the oxalate oxidase type activity in these strains which further strengthens the potentiality of these biocontrol agents.

Synthesis and structural characterisation of mixed An(IV)-An(III) actinide oxalates used as precursors for dedicated fuel or target

International Nuclear Information System (INIS)

Tamain, Christelle; Grandjean, Stephane; Arab Chapelet, Benedicte; Abraham, Francis

2010-01-01

Oxalic co-conversion process plays an important role by producing mixed-actinide compounds used as starting materials as they are particularly suitable precursors of actinide oxide solid solutions. In these oxalate compounds, a mixed crystallographic site which accommodates both elements in spite of their different oxidation states has been established. The charge compensation is ensured by monovalent cations present in the acidic solution. This communication reviews the various mixed-actinide oxalates obtained by crystallization from acidic solution. First, crystallographic structures determined by X-ray diffraction from single crystals are described. Then completing data obtained by powder X-ray diffraction are presented on various systems. The different supramolecular arrangements underline the complexity of An(IV)-An(III)/Ln(III) oxalate system and the need to pursue studies on single crystals. (authors)

Directed synthesis of crystalline plutonium (III) and (IV) oxalates: accessing redox-controlled separations in acidic solutions

International Nuclear Information System (INIS)

Runde, Wolfgang; Brodnax, Lia F.; Goff, George S.; Bean, Amanda C.; Scott, Brian L.

2009-01-01

Both binary and ternary solid complexes of Pu(III) and Pu(IV) oxalates have been previously reported in the literature. However, uncertainties regarding the coordination chemistry and the extent of hydration of some compounds remain mainly because of the absence of any crystallographic characterization. Single crystals of hydrated oxalates of Pu(III), Pu 2 (C 2 O 4 ) 3 (H 2 O) 6 ·3H 2 O (I) and Pu(IV), KPu(C 2 O 4 ) 2 (OH)·2.5H 2 O (II), were synthesized under moderate hydrothermal conditions and characterized by single crystal X-ray diffraction studies. Compounds I and II are the first plutonium(III) or (IV) oxalate compounds to be structurally characterized via single crystal X-ray diffraction studies. Crystallographic data for I: monoclinic, space group P21/c, a = 11.246(3) A, b = 9.610(3) A, c = 10.315(3) A, Z = 4 and II: monoclinic, space group C2/c, a = 23.234(14) A, b = 7.502(4) A, c = 13.029(7) A, Z = 8.

(Dimethylphosphorylmethanaminium hydrogen oxalate–oxalic acid (2/1

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Sebastian Bialek

2014-03-01

Full Text Available The reaction of (dimethylphosphorylmethanamine (dpma with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4−·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-molecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16° whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°. In the crystal, the components are connected by strong O—H...O and much weaker N—H...O hydrogen bonds, leading to the formation of layers extending parallel to (001. The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio.

Mixing state of oxalic acid containing particles in the rural area of Pearl River Delta, China: implications for the formation mechanism of oxalic acid

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C. Cheng

2017-08-01

Full Text Available The formation of oxalic acid and its mixing state in atmospheric particulate matter (PM were studied using a single-particle aerosol mass spectrometer (SPAMS in the summer and winter of 2014 in Heshan, a supersite in the rural area of the Pearl River Delta (PRD region in China. Oxalic-acid-containing particles accounted for 2.5 and 2.7 % in total detected ambient particles in summer and winter, respectively. Oxalic acid was measured in particles classified as elemental carbon (EC, organic carbon (OC, elemental and organic carbon (ECOC, biomass burning (BB, heavy metal (HM, secondary (Sec, sodium-potassium (NaK, and dust. Oxalic acid was found predominantly mixing with sulfate and nitrate during the whole sampling period, likely due to aqueous-phase reactions. In summer, oxalic-acid-containing particle number and ozone concentration followed a very similar trend, which may reflect the significant contribution of photochemical reactions to oxalic acid formation. The HM particles were the most abundant oxalic acid particles in summer and the diurnal variations in peak area of iron and oxalic acid show opposite trends, which suggests a possible loss of oxalic acid through the photolysis of iron oxalato-complexes during the strong photochemical activity period. In wintertime, carbonaceous particles contained a substantial amount of oxalic acid as well as abundant carbon clusters and BB markers. The general existence of nitric acid in oxalic-acid-containing particles indicates an acidic environment during the formation process of oxalic acid. The peak areas of nitrate, sulfate and oxalic had similar temporal change in the carbonaceous type oxalic acid particles, and the organosulfate-containing oxalic acid particles correlated well with total oxalic acid particles during the haze episode, which suggests that the formation of oxalic acid is closely associated with the oxidation of organic precursors in the aqueous phase.

Cable Supported Bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

Dating oxalate minerals in rock surface deposits

International Nuclear Information System (INIS)

Watchman, A.

2001-01-01

Oxalate minerals are found associated with rocks, mineral coatings, micro-organisms, plants and animals. They are important in archaeology because they have been found intimately associated with organic binders in prehistoric paints. Oxalate minerals also accumulate in the coatings on rock shelter walls and fallen ceiling slabs where they form the natural backing supports for painting and opaque laminates covering engravings. Though the relationship between anthropogenic activity in a rock shelter and oxalate formation is often uncertain, the radiocarbon age of the oxalate may provide the only means for determining the antiquity of a rock painting or engraving. This paper examines the history of dating oxalate minerals at archaeological sites and provides insights into achieving reliable age estimates. (author). 37 refs., 1 fig., 2 tabs

Cerium oxalate precipitation

International Nuclear Information System (INIS)

Chang, T.P.

1987-02-01

Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxalate precipitations in particle size and extent of plating, but not particle morphology. The equilibrium solubility, precipitation kinetics, particle size, extent of plating, and dissolution characteristics of cerium oxalate have been investigated. Interpretations of particle size and plating based on precipitation kinetics (i.e., nucleation and crystal growth) are presented. 16 refs., 7 figs., 6 tabs

Pathology and Epidemiology of Oxalate Nephrosis in Cheetahs.

Science.gov (United States)

Mitchell, Emily P; Church, Molly E; Nemser, Sarah M; Yakes, Betsy Jean; Evans, Eric R; Reimschuessel, Renate; Lemberger, Karin; Thompson, Peter N; Terio, Karen A

2017-11-01

To investigate cases of acute oxalate nephrosis without evidence of ethylene glycol exposure, archived data and tissues from cheetahs ( Acinonyx jubatus) from North America ( n = 297), southern Africa ( n = 257), and France ( n = 40) were evaluated. Renal and gastrointestinal tract lesions were characterized in a subset of animals with ( n = 100) and without ( n = 165) oxalate crystals at death. Crystals were confirmed as calcium oxalate by Raman spectroscopy in 45 of 47 cheetahs tested. Crystals were present in cheetahs from 3.7 months to 15.9 years old. Cheetahs younger than 1.5 years were less likely to have oxalates than older cheetahs ( P = .034), but young cheetahs with oxalates had more oxalate crystals than older cheetahs ( P Cheetahs with oxalate crystals were more likely to have renal amyloidosis, interstitial nephritis, or colitis and less likely to have glomerular loop thickening or gastritis than those without oxalates. Crystal number was positively associated with renal tubular necrosis ( P ≤ .001), regeneration ( P = .015), and casts ( P ≤ .001) but inversely associated with glomerulosclerosis, renal amyloidosis, and interstitial nephritis. Crystal number was unrelated to the presence or absence of colitis and was lower in southern African than American and European animals ( P = .01). This study found no evidence that coexisting chronic renal disease (amyloidosis, interstitial nephritis, or glomerulosclerosis), veno-occlusive disease, gastritis, or enterocolitis contributed significantly to oxalate nephrosis. Oxalate-related renal disease should be considered as a potential cause of acute renal failure, especially in young captive cheetahs. The role of location, diet, stress, and genetic predisposition in the pathogenesis of oxalate nephrosis in cheetahs warrants further study.

Precipitation of plutonium oxalate from homogeneous solutions

International Nuclear Information System (INIS)

Rao, V.K.; Pius, I.C.; Subbarao, M.; Chinnusamy, A.; Natarajan, P.R.

1986-01-01

A method for the precipitation of plutonium(IV) oxalate from homogeneous solutions using diethyl oxalate is reported. The precipitate obtained is crystalline and easily filterable with yields in the range of 92-98% for precipitations involving a few mg to g quantities of plutonium. Decontamination factors for common impurities such as U(VI), Am(III) and Fe(III) were determined. TGA and chemical analysis of the compound indicate its composition as Pu(Csub(2)Osub(4))sub(2).6Hsub(2)O. Data are obtained on the solubility of the oxalate in nitric acid and in mixtures of nitric acid and oxalic acid of varying concentrations. Green PuOsub(2) obtained by calcination of the oxalate has specifications within the recommended values for trace foreign substances such as chlorine, fluorine, carbon and nitrogen. (author)

Update on probiotics for the treatment of calcium oxalate stones

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Di ZHANG

2016-09-01

Full Text Available Urolithiasis is one of the common diseases in urinary system, among which calcium oxalate stone is the most common one with a high recurrence rate. An important pathological factor for the formation of calcium oxalate stone is the increased absorption of oxalate from intestine, which leads to a high urine oxalate concentration. Intestinal bacteria known to be able to degrade oxalate includes Oxalobacter formigenes, Enterococcus faecalis, Escherichia coli, Eubacterium lentum, Providencia rettgeri, Lactobacillus and Bifidobacterium species, etc. Among those, Oxalobacter formigenes is the first oxalate-degrading obligate anaerobe found in human, while the rest are just conditioned bacteria with the function to degrade intestinal oxalate. There are three kinds of enzymes in Oxalobacter formigenes involved in the metabolism of oxalate, namely oxalate-formate antiporter (OxlT, formyl-CoA transferase (Frc and oxalyl-CoA decarboxylase (Oxc. Animal experiments have verified that Oxalobacter formigenes could reduce intestinal oxalate absorption by promoting the secretion of oxalate and degradation as well, thus decrease the excretion of urine oxalate. The present review will focus on the research progress of probiotics treatment for the calcium oxalate stones so as to provide reference for further research and development. DOI: 10.11855/j.issn.0577-7402.2016.08.16

Advanced Oxidation: Oxalate Decomposition Testing With Ozone

International Nuclear Information System (INIS)

Ketusky, E.; Subramanian, K.

2012-01-01

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) after nearing

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

Combinatorial Synthesis of Structurally Diverse Triazole-Bridged Flavonoid Dimers and Trimers

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Tze Han Sum

2016-09-01

Full Text Available Flavonoids are a large family of compounds associated with a broad range of biologically useful properties. In recent years, synthetic compounds that contain two flavonoid units linked together have attracted attention in drug discovery and development projects. Numerous flavonoid dimer systems, incorporating a range of monomers attached via different linkers, have been reported to exhibit interesting bioactivities. From a medicinal chemistry perspective, the 1,2,3-triazole ring system has been identified as a particularly attractive linker moiety in dimeric derivatives (owing to several favourable attributes including proven biological relevance and metabolic stability and triazole-bridged flavonoid dimers possessing anticancer and antimalarial activities have recently been reported. However, there are relatively few examples of libraries of triazole-bridged flavonoid dimers and the diversity of flavonoid subunits present within these is typically limited. Thus, this compound type arguably remains underexplored within drug discovery. Herein, we report a modular strategy for the synthesis of novel and biologically interesting triazole-bridged flavonoid heterodimers and also very rare heterotrimers from readily available starting materials. Application of this strategy has enabled step-efficient and systematic access to a library of structurally diverse compounds of this sort, with a variety of monomer units belonging to six different structural subclasses of flavonoid successfully incorporated.

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.

Studies in the solubility of Pu(III) oxalate

Energy Technology Data Exchange (ETDEWEB)

Hasilkar, S P; Khedekar, N B; Chander, K; Jadhav, V; Jain, H C [Bhabha Atomic Research Centre, Bombay (India). Fuel Reprocessing Div.

1994-11-01

Studies have been carried out on the solubility of Pu(III) oxalate by precipitation of Pu(III) oxalate from varying concentrations of HNO[sub 3]/HCl (0.5-2.0M) solutions and also by equilibrating freshly prepared Pu(III) oxalate with solutions containing varying concentrations of HNO[sub 3]/HCl, oxalic acid and ascorbic acid. Pu(III) solutions in HNO[sub 3] and HCl media were prepared by reduction of Pu(IV) with ascorbic acid. 0.01-0.10M ascorbic acid concentration in the aqueous solution was maintained as holding reductant. The solubility of Pu(III) oxalate was found to be a minimum in 0.5M-1M HNO[sub 3]/HCl solutions containing 0.05M ascorbic acid and 0.2M excess oxalic acid in the supernatant. (author) 6 refs.; 6 tabs.

Atmospheric production of oxalic acid/oxalate and nitric acid/nitrate in the Tampa Bay airshed: Parallel pathways

Science.gov (United States)

Martinelango, P. Kalyani; Dasgupta, Purnendu K.; Al-Horr, Rida S.

Oxalic acid is the dominant dicarboxylic acid (DCA), and it constitutes up to 50% of total atmospheric DCAs, especially in non-urban and marine atmospheres. A significant amount of particulate H 2Ox/oxalate (Ox) occurred in the coarse particle fraction of a dichotomous sampler, the ratio of oxalate concentrations in the PM 10 to PM 2.5 fractions ranged from 1 to 2, with mean±sd being 1.4±0.2. These results suggest that oxalate does not solely originate in the gas phase and condense into particles. Gaseous H 2Ox concentrations are much lower than particulate Ox concentrations and are well correlated with HNO 3, HCHO, and O 3, supporting a photochemical origin. Of special relevance to the Bay Region Atmospheric Chemistry Experiment (BRACE) is the extent of nitrogen deposition in the Tampa Bay estuary. Hydroxyl radical is primarily responsible for the conversion of NO 2 to HNO 3, the latter being much more easily deposited. Hydroxyl radical is also responsible for the aqueous phase formation of oxalic acid from alkenes. Hence, we propose that an estimate of rad OH can be obtained from H 2Ox/Ox production rate and we accordingly show that the product of total oxalate concentration and NO 2 concentration approximately predicts the total nitrate concentration during the same period.

Oxalic acid decreases calcium absorption in rats

International Nuclear Information System (INIS)

Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

1987-01-01

Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

Oxalate Content of Taro Leaves Grown in Central Vietnam

Science.gov (United States)

Du Thanh, Hang; Phan Vu, Hai; Vu Van, Hai; Le Duc, Ngoan; Le Minh, Tuan; Savage, Geoffrey

2017-01-01

Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM) while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35%) of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%). There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%). The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption. PMID:28231080

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

Oxalate quantification in hemodialysate to assess dialysis adequacy for primary hyperoxaluria.

Science.gov (United States)

Tang, Xiaojing; Voskoboev, Nikolay V; Wannarka, Stacie L; Olson, Julie B; Milliner, Dawn S; Lieske, John C

2014-01-01

Patients with primary hyperoxaluria (PH) overproduce oxalate which is eliminated via the kidneys. If end-stage kidney disease develops they are at high risk for systemic oxalosis, unless adequate oxalate is removed during hemodialysis (HD) to equal or exceed ongoing oxalate production. The purpose of this study was to validate a method to measure oxalate removal in this unique group of dialysis patients. Fourteen stable patients with a confirmed diagnosis of PH on HD were included in the study. Oxalate was measured serially in hemodialysate and plasma samples in order to calculate rates of oxalate removal. HD regimens were adjusted according to a given patient's historical oxalate production, amount of oxalate removal at dialysis, residual renal clearance of oxalate, and plasma oxalate levels. After a typical session of HD, plasma oxalate was reduced by 78.4 ± 7.7%. Eight patients performed HD 6 times/week, 2 patients 5 times/week, and 3 patients 3 times/week. Combined oxalate removal by HD and the kidneys was sufficient to match or exceed endogenous oxalate production. After a median period of 9 months, pre-dialysis plasma oxalate was significantly lower than initially (75.1 ± 33.4 vs. 54.8 ± 46.6 mmol/l, p = 0.02). This methodology can be used to individualize the dialysis prescription of PH patients to prevent oxalosis during the time they are maintained on HD and to reduce risk of oxalate injury to a transplanted kidney.

Acute oxalate nephropathy caused by ethylene glycol poisoning

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Jung Woong Seo

2012-12-01

Full Text Available Ethylene glycol (EG is a sweet-tasting, odorless organic solvent found in many agents, such as anti-freeze. EG is composed of four organic acids: glycoaldehyde, glycolic acid, glyoxylic acid and oxalic acid in vivo. These metabolites are cellular toxins that can cause cardio-pulmonary failure, life-threatening metabolic acidosis, central nervous system depression, and kidney injury. Oxalic acid is the end product of EG, which can precipitate to crystals of calcium oxalate monohydrate in the tubular lumen and has been linked to acute kidney injury. We report a case of EG-induced oxalate nephropathy, with the diagnosis confirmed by kidney biopsy, which showed acute tubular injury of the kidneys with extensive intracellular and intraluminal calcium oxalate monohydrate crystal depositions.

Oxalate Content of the Herb Good-King-Henry, Blitum Bonus-Henricus

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Wanying Li

2015-05-01

Full Text Available The total, soluble and insoluble oxalate contents of the leaves, stems and buds of Good-King-Henry (Blitum Bonus-Henricus were extracted and measured using HPLC chromatography. The large, mature leaves contained 42% more total oxalate than in the small leaves and the soluble oxalate content of the large leaves was 33% higher than the smaller leaves. Cooking the mixed leaves, stems and buds in boiling water for two minutes significantly (p < 0.05 reduced the total oxalate when compared to the raw plant parts. Pesto sauce made from mixed leaves contained 257 mg total oxalate/100 g fresh weight; this was largely made up of insoluble oxalates (85% of the total oxalate content. Soup made from mixed leaves contained lower levels of total oxalates (44.26 ± 0.49 mg total oxalate/100 g fresh weight and insoluble oxalate made up 49% of the oxalate contents. The levels of oxalates in the Good-King-Henry leaves were high, suggesting that the leaves should be consumed occasionally as a delicacy because of their unique taste rather than as a significant part of the diet. However, the products made from Good-King-Henry leaves indicated that larger amounts could be consumed as the oxalate levels were reduced by dilution and processing.

Preparation of [11C]diethyl oxalate and [11C]oxalic acid and demonstration of their use in the synthesis of [11C]-2,3-dihydroxyquinoxaline

International Nuclear Information System (INIS)

Thorell, J.-O.; Stone-Elander, S.

1993-01-01

A method for the production of two new carbon-11 labelled difunctional radiolabelling precursors, [ 11 C]diethyl oxalate,2, and [ 11 C]oxalic acid, 3 is described. Methyl chloroformate was reacted with no-carrier-added [ 11 C]cyanide to generate the intermediate nitrile, methyl [ 11 C]cyanoformate. Alcoholysis with HC1 in ethanol generated 2, which could subsequently be converted to 3 with aqueous acid. The total time of preparation from end-or-trapping of [ 11 C]cyanide was 6-7 min using combined microwave and thermal treatment or, by exclusively thermal treatment, 15 and 20 min for 2 and 3, respectively. The radiochemical conversion of [ 11 C]cyanide to 2 and 3 was ∼ 80% and ∼ 70%, respectively. Both 2 and 3 were used in a model reaction with 1,2-phenylenediamine to synthesize the heterocyclic compound, 2,3-dihydroxyquinoxaline, a basic structural unit in antagonists for the excitatory amino acid receptor system. (Author)

Oxalate Content of Taro Leaves Grown in Central Vietnam

Directory of Open Access Journals (Sweden)

Hang Du Thanh

2017-01-01

Full Text Available Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35% of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%. There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%. The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption.

Urinary oxalate to creatinine ratios in healthy Turkish schoolchildren.

Science.gov (United States)

Dursun, Ismail; Çelik, İlknur; Poyrazoglu, Hakan M; Köse, Kader; Tanrıkulu, Esen; Sahin, Habibe; Yılmaz, Kenan; Öztürk, Ahmet; Yel, Sibel; Gündüz, Zübeyde; Düşünsel, Ruhan

2017-11-01

we aimed to establish reference values for urinary oxalate to creatinine ratios in healthy children aged 6-15 years and to investigate the relationship between their nutritional habits and oxalate excretion. Random urine specimens from 953 healthy children aged 6-15 years were obtained and analyzed for oxalate and creatinine. Additionally, a 24-h dietary recall form was prepared and given to them. The ingredient composition of the diet was calculated. The children were divided into three groups according to age: Group I (69 years, n = 353), Group II (10-12 years, n = 335), and Group III (13-15 years, n = 265). The 95th percentile of the oxalate to creatinine ratio for subjects aged 6-9, 10-12, and 13-15 years were 0.048, 0.042, and 0.042 mg/mg, respectively. The oxalate to creatinine ratio was significantly higher in Group 1 than in Group 2 and Group 3. Urinary oxalate excretion was positively correlated with increased protein intake and negatively correlated with age. A significant positive correlation was determined between urinary oxalate excretion and the proline, serine, protein, and glycine content of diet. Dietary proline intake showed a positive correlation with the urine oxalate to creatinine ratio and was found to be an independent predictor for urinary oxalate. These data lend support to the idea that every country should have its own normal reference values to determine the underlying metabolic risk factor for kidney stone disease since regional variation in the dietary intake of proteins and other nutrients can affect normal urinary excretion of oxalate.

Pseudomonas fluorescens ATCC 13525 Containing an Artificial Oxalate Operon and Vitreoscilla Hemoglobin Secretes Oxalic Acid and Solubilizes Rock Phosphate in Acidic Alfisols

OpenAIRE

Yadav, Kavita; Kumar, Chanchal; Archana, G.; Naresh Kumar, G.

2014-01-01

Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah), Fomitopsis plaustris oxalate transporter (FpOAR) and Vitreoscilla hemoglobin (vgb) in various combinations. Pf (pKCN2) transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4) s...

Sustainable Synthesis of Oxalic and Succinic Acid through Aerobic Oxidation of C6 Polyols Under Mild Conditions.

Science.gov (United States)

Ventura, Maria; Williamson, David; Lobefaro, Francesco; Jones, Matthew D; Mattia, Davide; Nocito, Francesco; Aresta, Michele; Dibenedetto, Angela

2018-03-22

The sustainable chemical industry encompasses a shift from the use of fossil carbon to renewable carbon. The synthesis of chemicals from nonedible biomass (cellulosic or oil) represents one of the key steps for "greening" the chemical industry. In this paper, we report the aerobic oxidative cleavage of C6 polyols (5-HMF, glucose, fructose and sucrose) to oxalic acid (OA) and succinic acid (SA) in water under mild conditions using M@CNT and M@NCNT (M=Fe, V; CNT=carbon nanotubes; NCNT=N-doped CNT), which, under suitable conditions, were recoverable and reusable without any loss of efficiency. The influence of the temperature, O 2 pressure (PO2 ), reaction time and stirring rate are discussed and the best reaction conditions are determined for an almost complete conversion of the starting material and a good OA yield of 48 %. SA and formic acid were the only co-products. The former could be further converted into OA by oxidation in the presence of formic acid, resulting in an overall OA yield of >62 %. This process was clean and did not produce organic waste nor gas emissions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Addition of calcium compounds to reduce soluble oxalate in a high oxalate food system.

Science.gov (United States)

Bong, Wen-Chun; Vanhanen, Leo P; Savage, Geoffrey P

2017-04-15

Spinach (Spinacia oleracea L.) is often used as a base vegetable to make green juices that are promoted as healthy dietary alternatives. Spinach is known to contain significant amounts of oxalates, which are toxic and, if consumed regularly, can lead to the development of kidney stones. This research investigates adding 50-500mg increments of calcium carbonate, calcium chloride, calcium citrate and calcium sulphate to 100g of raw homogenates of spinach to determine whether calcium would combine with the soluble oxalate present in the spinach. Calcium chloride was the most effective additive while calcium carbonate was the least effective. The formation of insoluble oxalate after incubation at 25°C for 30min is a simple practical step that can be incorporated into the juicing process. This would make the juice considerably safer to consume on a regular basis. Copyright © 2016 Elsevier Ltd. All rights reserved.

4-Methoxybenzamidinium hydrogen oxalate monohydrate

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Simona Irrera

2012-12-01

Full Text Available The title hydrated salt, C8H11N2O+·C2HO4−·H2O, was synthesized by a reaction of 4-methoxybenzamidine (4-amidinoanisole and oxalic acid in water solution. In the cation, the amidinium group forms a dihedral angle of 15.60 (6° with the mean plane of the benzene ring. In the crystal, each amidinium unit is bound to three acetate anions and one water molecule by six distinct N—H...O hydrogen bonds. The ion pairs of the asymmetric unit are joined by two N—H...O hydrogen bonds into ionic dimers in which the carbonyl O atom of the semi-oxalate anion acts as a bifurcated acceptor, thus generating an R12(6 motif. These subunits are then joined through the remaining N—H...O hydrogen bonds to adjacent semi-oxalate anions into linear tetrameric chains running approximately along the b axis. The structure is stabilized by N—H...O and O—H...O intermolecular hydrogen bonds. The water molecule plays an important role in the cohesion and the stability of the crystal structure being involved in three hydrogen bonds connecting two semi-oxalate anions as donor and a benzamidinium cation as acceptor.

Acute oxalate nephropathy after ingestion of star fruit.

Science.gov (United States)

Chen, C L; Fang, H C; Chou, K J; Wang, J S; Chung, H M

2001-02-01

Acute oxalate nephropathy associated with ingestion of star fruit (carambola) has not been reported before. We report the first two cases. These patients developed nausea, vomiting, abdominal pain, and backache within hours of ingesting large quantities of sour carambola juice; then acute renal failure followed. Both patients needed hemodialysis for oliguric acute renal failure, and pathologic examinations showed typical changes of acute oxalate nephropathy. The renal function recovered 4 weeks later without specific treatment. Sour carambola juice is a popular beverage in Taiwan. The popularity of star fruit juice is not compatible with the rare discovery of star fruit-associated acute oxalate nephropathy. Commercial carambola juice usually is prepared by pickling and dilution processes that reduce oxalate content markedly, whereas pure fresh juice or mild diluted postpickled juice for traditional remedies, as used in our cases, contain high quantities of oxalate. An empty stomach and dehydrated state may pose an additional risk for development of renal injury. To avoid acute oxalate nephropathy, pure sour carambola juice or mild diluted postpickled juice should not be consumed in large amounts, especially on an empty stomach or in a dehydrated state.

Superhydrophobic hybrid membranes by grafting arc-like macromolecular bridges on graphene sheets: Synthesis, characterization and properties

Science.gov (United States)

Mo, Zhao-Hua; Luo, Zheng; Huang, Qiang; Deng, Jian-Ping; Wu, Yi-Xian

2018-05-01

Grafting single end-tethered polymer chains on the surface of graphene is a conventional way to modify the surface properties of graphene oxide. However, grafting arc-like macromolecular bridges on graphene surfaces has been barely reported. Herein, a novel arc-like polydimethylsiloxane (PDMS) macromolecular bridges grafted graphene sheets (GO-g-Arc PDMS) was successfully synthesized via a confined interface reaction at 90 °C. Both the hydrophilic α- and ω-amino groups of linear hydrophobic NH2-PDMS-NH2 macromolecular chains rapidly reacted with epoxy and carboxyl groups on the surfaces of graphene oxide in water suspension to form arc-like PDMS macromolecular bridges on graphene sheets. The grafting density of arc-like PDMS bridges on graphene sheets can reach up to 0.80 mmol g-1 or 1.32 arc-like bridges per nm2 by this confined interface reaction. The water contact angle (WCA) of the hybrid membrane could be increased with increasing both the grafting density and content of covalent arc-like bridges architecture. The superhydrophobic hybrid membrane with a WCA of 153.4° was prepared by grinding of the above arc-like PDMS bridges grafted graphene hybrid, dispersing in ethanol and filtrating by organic filter membrane. This superhydrophobic hybrid membrane shows good self-cleaning and complete oil-water separation properties, which provides potential applications in anticontamination coating and oil-water separation. To the best of our knowledge, this is the first report on the synthesis of functional hybrid membranes by grafting arc-like PDMS macromolecular bridges on graphene sheets via a confined interface reaction.

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.

1D and 2D Cobalt(II) Coordination Polymers, Co(ox)(en):Synthesis, Structures and Magnetic Properties

International Nuclear Information System (INIS)

Kang, Jae Un; Lee, Yu Mi; Kim, Seung Joo; Yun, Ho Seop; Do, Jung Hwan

2014-01-01

Two ethylenediamine cobalt(II) oxalate complexes Co(ox)(en), 1 and Co(ox)(en)·2H 2 O, 2 have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, IR spectrum, TG analysis, and magnetic measurements. In 1, Co atoms are coordinated by two bis-bidentate oxalate ions in transconfiguration to form Co(ox) chains, which are further bridged by ethylenediamine molecules to produce 2D grid layers, Co(ox)(en). In 2, Co atoms are coordinated by bridging oxalate ions in cis - configuration to form Co(ox) chains, and the additional chelation of ethylenediamine to Co atoms completes 1D zigzag chain, Co(en)(ox). Two lattice water molecules stabilize the chains through hydrogen bonding. Magnetic susceptibility measurements indicate that both complexes exhibit weak antiferromagnetic coupling between cobalt(II) ions with the susceptibility maxima at 23 K for 1 and 20 K for 2, respectively. In 1 and 2, the oxalate ligands afford a much shorter and more effective pathway for the magnetic interaction between cobalt ions compared to the ethylenediamine ligands, so the magnetic behaviors of both complexes could be well described with 1D infinite magnetic chain model

Oxalic acid has an additional, detoxifying function in Sclerotinia sclerotiorum pathogenesis.

Directory of Open Access Journals (Sweden)

Annerose Heller

Full Text Available The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi. Calcium oxalate crystals were detected in advanced (36-48 hpi and late (72 hpi infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages.

Growth of strontium oxalate crystals in agar–agar gel

Indian Academy of Sciences (India)

Growth of strontium oxalate crystals in agar–agar gel. P V DALAL. ∗ and K B SARAF. Postgraduate Department of Physics, Pratap College, Amalner 425 401, India. MS received 16 March 2008; revised 5 April 2010. Abstract. Single crystals of strontium oxalate have been grown by using strontium chloride and oxalic acid in.

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.

Radiolysis of titanium potassium oxalate in aqueous solution. [. gamma. rays

Energy Technology Data Exchange (ETDEWEB)

Bundo, Y; Ono, I [Industrial Research Inst. of Kanagawa Prefecture, Yokohama (Japan); Ogawa, T

1975-01-01

The dissolution state of titanium potassium oxalate in aqueous solution is different according to the pH. The yellowish brown titanium complex produced by the reaction of titanium potassium oxalate and hydrogen peroxide seems to be different in its structure according to the pH. Considering these points, gamma-ray irradiation was carried out on the sample by dissolving titanium potassium oxalate in purified water under the conditions of oxygen saturation and nitrogen saturation, and the relation between irradiation dose and the production of titanium complex was determined. On the basis of the experimental result, the mechanism of forming hydrogen peroxide was presumed. The radiation source used was 2,000 Ci of /sup 60/Co. For photometric analysis, a 139 type photoelectric spectrophotometer of Hitachi Ltd. was used. From the experimental results, in neutral water, titanium potassium oxalate exists in the state that two oxalic acid ions are coordinated to titanyl ion, while in case of the pH lowered by the addition of sulfuric acid, it can exist in the state that one oxalic acid ion is coordinated to titanyl ion. The yield of hydrogen peroxide produced by irradiating titanium potassium oxalate aqueous solution with gamma-ray is the sum of the molecular product from water and the radiolysis product from titanium potassium oxalate.

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.

Effect of heat treatment on the structure of incorporated oxalate species and photoluminescent properties of porous alumina films formed in oxalic acid

Science.gov (United States)

Vrublevsky, I.; Jagminas, A.; Hemeltjen, S.; Goedel, W. A.

2008-09-01

The present work focuses on the use of IR spectroscopy and photoluminescence spectral measurements for studying the treatment temperature effect on the compositional and luminescent properties of oxalic acid alumina films. In line with the recent researches we have also found that heat treatment of porous alumina films formed in oxalic acid leads to considerable changes in their photoluminescence properties: upon annealing the intensity of photoluminescence (PL) increases reaching a maximum at the temperature of around 500 °C and then decreases. IR spectra of as-grown and heat-treated films have proved that PL emission in the anodic alumina films is related with the state of 'structural' oxalate species incorporated in the oxide lattice. These results allowed us to conclude that PL behavior of oxalic acid alumina films can be explained through the concept of variations in the bonding molecular orbitals of incorporated oxalate species including σ- and π-bonds.

Effect of medium pH on chemical selectivity of oxalic acid biosynthesis by Aspergillus niger W78C in submerged batch cultures with sucrose as a carbon source.

Science.gov (United States)

Walaszczyk, Ewa; Podgórski, Waldemar; Janczar-Smuga, Małgorzata; Dymarska, Ewelina

2018-01-01

The pH of the medium is the key environmental parameter of chemical selectivity of oxalic acid biosynthesis by Aspergillus niger . The activity of the enzyme oxaloacetate hydrolase, which is responsible for decomposition of oxaloacetate to oxalate and acetate inside the cell of the fungus, is highest at pH 6. In the present study, the influence of pH in the range of 3-7 on oxalic acid secretion by A. niger W78C from sucrose was investigated. The highest oxalic acid concentration, 64.3 g dm -3 , was reached in the medium with pH 6. The chemical selectivity of the process was 58.6% because of the presence of citric and gluconic acids in the cultivation broth in the amount of 15.3 and 30.2 g dm -3 , respectively. Both an increase and a decrease of medium pH caused a decrease of oxalic acid concentration. The obtained results confirm that pH 6 of the carbohydrate medium is appropriate for oxalic acid synthesis by A. niger , but the chemical selectivity of the process described in this paper was high in comparison to values reported previously in the literature.

Structural variability in neptunium(V) oxalate compounds: synthesis and structural characterization of Na2NpO2(C2O4)OH.H2O.

Science.gov (United States)

Bean, Amanda C; Garcia, Eduardo; Scott, Brian L; Runde, Wolfgang

2004-10-04

Reaction of a (237)Np(V) stock solution in the presence of oxalic acid, calcium chloride, and sodium hydroxide under hydrothermal conditions produces single crystals of a neptunium(V) oxalate, Na(2)NpO(2)(C(2)O(4))OH.H(2)O. The structure consists of one-dimensional chains running down the a axis and is the first example of a neptunium(V) oxalate compound containing hydroxide anions.

Novel methods for the synthesis of magnetite nanoparticles with special morphologies and textured assemblages

Energy Technology Data Exchange (ETDEWEB)

Nyiro-Kosa, Ilona, E-mail: kosaili@gmail.com [University of Pannonia, Department of Material Engineering (Hungary); Recnik, Aleksander [Jozef Stefan Institute, Department for Nanostructured Materials (Slovenia); Posfai, Mihaly [University of Pannonia, Department of Earth and Environmental Sciences (Hungary)

2012-10-15

There is an increasing technological demand for magnetic nanocrystals with special morphologies and controlled sizes. Several approaches are used for the synthesis of magnetite crystals with irregular or octahedral shapes; however, the room-temperature synthesis of nanocrystals with specific morphologies is not yet established. Here, we describe the synthesis of magnetite crystals (100-300 nm) at a relatively low temperature ({approx}70 Degree-Sign C) from organic precursors, including Fe(II) oxalate or Fe(II) sulfate, and study the effects of ethylene glycol and tetraethylene glycol on the final physical and chemical properties of the crystals. The magnetite crystals formed from different precursor materials (sulfate or oxalate green rust) show specific morphological and textural features. We show that octahedral magnetite crystals can be produced from Fe(II) oxalate via a simple co-precipitation process. Using different kinds and amounts of polyols, various types of particle morphologies and nanocrystal textures can be produced, including hexagonal-shaped clusters of elongated crystals and porous and solid, large, rounded polycrystalline aggregates.

Novel methods for the synthesis of magnetite nanoparticles with special morphologies and textured assemblages

International Nuclear Information System (INIS)

Nyirő-Kósa, Ilona; Rečnik, Aleksander; Pósfai, Mihály

2012-01-01

There is an increasing technological demand for magnetic nanocrystals with special morphologies and controlled sizes. Several approaches are used for the synthesis of magnetite crystals with irregular or octahedral shapes; however, the room-temperature synthesis of nanocrystals with specific morphologies is not yet established. Here, we describe the synthesis of magnetite crystals (100–300 nm) at a relatively low temperature (∼70 °C) from organic precursors, including Fe(II) oxalate or Fe(II) sulfate, and study the effects of ethylene glycol and tetraethylene glycol on the final physical and chemical properties of the crystals. The magnetite crystals formed from different precursor materials (sulfate or oxalate green rust) show specific morphological and textural features. We show that octahedral magnetite crystals can be produced from Fe(II) oxalate via a simple co-precipitation process. Using different kinds and amounts of polyols, various types of particle morphologies and nanocrystal textures can be produced, including hexagonal-shaped clusters of elongated crystals and porous and solid, large, rounded polycrystalline aggregates.

Neurotoxic effects of carambola in rats: the role of oxalate.

Science.gov (United States)

Chen, Chien-Liang; Chou, Kang-Ju; Wang, Jyh-Seng; Yeh, Jeng-Hsien; Fang, Hua-Chang; Chung, Hsiao-Min

2002-05-01

Carambola (star fruit) has been reported to contain neurotoxins that cause convulsions, hiccups, or death in uremic patients, and prolong barbiturate-induced sleeping time in rats. The constituent responsible for these effects remains uncertain. Carambola contains a large quantity of oxalate, which can induce depression of cerebral function and seizures. This study was conducted to investigate the role of oxalate in carambola toxicity in rats. The effects on barbiturate-induced sleeping time and death caused by intraperitoneal administration of carambola juice were observed in Sprague-Dawley rats. To obtain a dose-dependent response curve and evaluate the lethal dose, rats were treated with serial amounts of pure carambola juice diluted with normal saline in a volume of 1:1. To test the role of oxalate in the neurotoxic effect of carambola, either 5.33 g/kg carambola after oxalate removal or 5.33 g/kg of pure carambola juice diluted with normal saline were administered intraperitoneally, while the control group was given normal saline before pentobarbital injection. The effects of carambola and oxalate-removed carambola on barbiturate-induced sleeping time were compared with those of saline. To assess the lethal effect of oxalate in carambola, we gave rats chemical oxalate at comparable concentrations to the oxalate content of carambola. Carambola juice administration prolonged barbiturate-induced sleeping time in a dose-dependent manner. The sleeping time of rats that received normal saline and 1.33 g/kg, 2.67 g/kg, 5.33 g/kg, and 10.67 g/kg of carambola juice were 66 +/- 16.6, 93.7 +/- 13.4, 113.3 +/- 11.4, 117.5 +/- 29.0, and 172.5 +/- 38.8 minutes, respectively. The three higher-dose groups had longer sleeping times than controls (p carambola juice. Four of eight rats in the 10.67-g/kg group and all rats in the 21.33 g/kg and chemical oxalate groups died after seizure. Lethal doses of carambola juice were rendered harmless by the oxalate removal procedure

Synthesis, structure and characterization of two new open-framework gallium phosphite-oxalates of varying dimensionality

International Nuclear Information System (INIS)

Li, Caixia; Huang, Liangliang; Zhou, Mingdong; Xia, Jing; Ma, Hongwei; Zang, Shuliang; Wang, Li

2013-01-01

Using N, N-dimethyl-piperazine as structure directing agent, two new gallium phosphite-oxalates [Ga 2 (HPO 3 ) 2 (H 2 PO 3 ) 2 (C 2 O 4 )](C 6 N 2 H 16 ) (I) and [Ga 2 (HPO 3 ) 2 (H 2 PO 3 )(C 2 O 4 )](C 6 N 2 H 16 ) 0.5 (II) have been synthesized under solvothermal and hydrothermal conditions, respectively and further characterized by powder X-ray diffraction, IR spectroscopy, TGA, ICP-AES and elemental analyses. Single crystal X-ray diffraction reveals that the striking feature of I and II is that they possess the same second building unit (SBU) Ga 2 P 2 constructed from two GaO 6 octahedra and two [HPO 3 2− ] pseudo-pyramids sharing oxygen atoms. However, due to the different connecting fashions of SBUs, [C 2 O 4 2− ] groups and [H 2 PO 3 − ] pseudo-pyramids, the final frameworks of them are distinctly different. Compound I shows 2D layered structures with 8-membered ring (8-MR) windows in the ab plane while compound II presents a 3D open-framework with 8-MR channels along the b axis. - Graphical abstract: Using N, N-dimethyl-piperazine as structure directing agent, two new gallium phosphite-oxalates I showing 2D layered structure and II presenting 3D open-framework have been synthesized under solvothermal and hydrothermal conditions, respectively. - Highlights: • Using N, N-dimethyl-piperazine as structure directing agent, two new gallium phosphite-oxalates have been synthesized under solvothermal and hydrothermal conditions, respectively. • The same second building unit (SBU) is displayed in both compounds. • Compound I shows 2D layered structure with 8-MR windows while compound II presents 3D open-framework with 8-MR channels. • The solvent plays an important role on the formation of microporous compounds

Oxalic acid biosynthesis and oxalacetate acetylhydrolase activity in Streptomyces cattleya

International Nuclear Information System (INIS)

Houck, D.R.; Inamine, E.

1987-01-01

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- 14 C]aspartate proved to be the best precursor, whereas only a small percentage of label from [1,5- 14 C]citrate was found in oxalate. Cell-free extracts catalyzed the formation of [ 14 C]oxalate and [ 14 C]acetate from L-[U- 14 C]aspartate. When L-[4- 14 C]aspartate was the substrate only [ 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

Isolation and some characteristics of anaerobic oxalate-degrading bacteria from the rumen.

OpenAIRE

Dawson, K A; Allison, M J; Hartman, P A

1980-01-01

Obligately anaerobic oxalate-degrading bacteria were isolated from an enriched population of rumen bacteria in an oxalate-containing medium that had been depleted of other readily metabolized substrates. These organisms, which are the first reported anaerobic oxalate degraders isolated from the rumen, were gram negative, nonmotile rods. They grew in a medium containing sodium oxalate, yeast extract, cysteine, and minerals. The only substrate that supported growth was oxalate. Growth was direc...

Spectroscopic properties of Pr -doped erbium oxalate crystals

Indian Academy of Sciences (India)

Spectroscopic properties of praseodymium ions-doped erbium oxalate ... solution with specific gravity 1.04 g/cm3 was mixed homogeneously with 0.5 M oxalic ... of concentrated nitric acid were transferred carefully and gently through the wall ...

Preparation of [[sup 11]C]diethyl oxalate and [[sup 11]C]oxalic acid and demonstration of their use in the synthesis of [[sup 11]C]-2,3-dihydroxyquinoxaline

Energy Technology Data Exchange (ETDEWEB)

Thorell, J -O; Stone-Elander, S [Karolinska Pharmacy, Stockholm (Sweden) Karolinska Hospital and Institute, Stockholm (Sweden). Dept. of Clinical Neurophysiology; Elander, N [Manne Siegbahn Inst. of Physics, Stockholm (Sweden)

1993-11-01

A method for the production of two new carbon-11 labelled difunctional radiolabelling precursors, [[sup 11]C]diethyl oxalate,2, and [[sup 11]C]oxalic acid, 3 is described. Methyl chloroformate was reacted with no-carrier-added [[sup 11]C]cyanide to generate the intermediate nitrile, methyl [[sup 11]C]cyanoformate. Alcoholysis with HC1 in ethanol generated 2, which could subsequently be converted to 3 with aqueous acid. The total time of preparation from end-or-trapping of [[sup 11]C]cyanide was 6-7 min using combined microwave and thermal treatment or, by exclusively thermal treatment, 15 and 20 min for 2 and 3, respectively. The radiochemical conversion of [[sup 11]C]cyanide to 2 and 3 was [approx] 80% and [approx] 70%, respectively. Both 2 and 3 were used in a model reaction with 1,2-phenylenediamine to synthesize the heterocyclic compound, 2,3-dihydroxyquinoxaline, a basic structural unit in antagonists for the excitatory amino acid receptor system. (Author).

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.

Influence of additives on the structure and microstructure of lanthanides and actinides oxalates

International Nuclear Information System (INIS)

Haidon, Blaise; Vitart, Anne-Lise; Rivenet, Murielle; Arab-Chapelet, Benedicte; Roussel, Pascal; Delahaye, Thibaud; Grandjean, Stephane; Abraham, Francis

2015-07-01

Oxalic conversion is a well-known process in the nuclear industry where it is used for precipitating plutonium as an oxalate thereafter calcinated into an oxide. As there is a strong relationship between the morphology of the oxalate precursor and that of the resulting oxide, it is of interest to control the oxalate structure and microstructure during the precipitation step. The influence of additives on the precipitation of neodymium (III) oxalates, non-radioactive analogs of actinides (III) oxalates, was explored. With the use of nitrilotri-methylphosphonic acid (NTMP), the structure and microstructure of the neodymium oxalates are different from that obtained without additive. (authors)

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

Decontamination effectiveness of mixtures of citric acid, oxalic acid and EDTA

International Nuclear Information System (INIS)

Speranzini, R.A.

1990-01-01

An experimental study of the decontamination effectiveness of citric acid, oxalic acid and EDTA mixtures was conducted to assess whether oxalic acid could be removed from decontamination solutions to minimize corrosion. In loop experiments, radioactive specimens from two boiling water reactors and one pressurized water reactor were suspended in solutions of single acids or in mixtures of reagents at total reagent concentrations of less than 0.1 wt% under conditions similar to those used to decontaminate reactor systems. Rate constants for dissolution of oxides and decontamination factors were measured. Based on the results, it was concluded that under certain conditions, oxalic acid was the most effective reagent for the dissolution of oxides. It was also found, however, that conditions under which effective dissolution occurred in solutions of oxalic acid and/or citric acid were difficult to define and control. EDTA was found to be an effective reagent for dissolution of oxides such that rates of dissolution in EDTA containing solutions at 117 degrees Celsius were comparable to rates in oxalic acid containing solutions. At 90 degrees Celsius, EDTA acted synergistically with oxalic acid such that the rate of dissolution of oxides in citric-acid/oxalic-acid/EDTA solutions was higher than in citric-acid/EDTA solutions. The rates of dissolution of oxides were significantly reduced when 60 mg/kg of ferric ion was added to the citric-acid/oxalic-acid, citric-acid/EDTA and citric-acid/oxalic-acid/EDTA solutions. It was concluded that effective decontaminations of BWR and PWR systems could be achieved with mixtures of citric acid and EDTA

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.

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.

The metabolic and ecological interactions of oxalate-degrading bacteria in the Mammalian gut.

Science.gov (United States)

Miller, Aaron W; Dearing, Denise

2013-12-06

Oxalate-degrading bacteria comprise a functional group of microorganisms, commonly found in the gastrointestinal tract of mammals. Oxalate is a plant secondary compound (PSC) widely produced by all major taxa of plants and as a terminal metabolite by the mammalian liver. As a toxin, oxalate can have a significant impact on the health of mammals, including humans. Mammals do not have the enzymes required to metabolize oxalate and rely on their gut microbiota for this function. Thus, significant metabolic interactions between the mammalian host and a complex gut microbiota maintain the balance of oxalate in the body. Over a dozen species of gut bacteria are now known to degrade oxalate. This review focuses on the host-microbe and microbe-microbe interactions that regulate the degradation of oxalate by the gut microbiota. We discuss the pathways of oxalate throughout the body and the mammalian gut as a series of differentiated ecosystems that facilitate oxalate degradation. We also explore the mechanisms and functions of microbial oxalate degradation along with the implications for the ecological and evolutionary interactions within the microbiota and for mammalian hosts. Throughout, we consider questions that remain, as well as recent technological advances that can be employed to answer them.

Two-stage precipitation of neptunium (IV) oxalate

International Nuclear Information System (INIS)

Luerkens, D.W.

1983-07-01

Neptunium (IV) oxalate was precipitated using a two-stage precipitation system. A series of precipitation experiments was used to identify the significant process variables affecting precipitate characteristics. Process variables tested were input concentrations, solubility conditions in the first stage precipitator, precipitation temperatures, and residence time in the first stage precipitator. A procedure has been demonstrated that produces neptunium (IV) oxalate particles that filter well and readily calcine to the oxide

Preparation, characterization and catalytic effects of copper oxalate nanocrystals

International Nuclear Information System (INIS)

Singh, Gurdip; Kapoor, Inder Pal Singh; Dubey, Reena; Srivastava, Pratibha

2012-01-01

Graphical abstract: Prepared copper oxalate nanocrystals were characterized by FE-SEM and bright field TEM micrographs. Its catalytic activity was evaluated on the thermal decomposition of ammonium perchlorate using TG and TG-DSC techniques. Highlights: ► Preparation of nanocrystals (∼9.0 nm) of copper oxalate using Cu(NO 3 ) 2 ·2H 2 O, oxalic acid and acetone under thermal conditions. ► Method is simple and novel. ► Characterization using XRD, SEM, TEM, HRTEM and ED pattern. ► Catalytic activity of copper oxalate nanocrystals on AP thermal decomposition using thermal techniques (TG, TG-DSC and ignition delay). ► Kinetics of thermal decomposition of AP + CONs using isoconversional and model fitting kinetic approaches. - Abstract: Recent work has described the preparation and characterization of copper oxalate nanocrystals (CONs). It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and electron diffraction pattern (ED). The catalytic activity of CONs on the thermal decomposition of ammonium perchlorate (AP) and composite solid propellants (CSPs) has been done by thermogravimetry (TG), differential scanning calorimetry (DSC) and ignition delay measurements. Burning rate of CSPs was also found to be enhanced in presence of copper oxalate nanocrystals. Kinetics of thermal decomposition of AP with and without CONs has also been investigated. The model free (isoconversional) and model-fitting kinetic approaches have been applied to data for isothermal TG decomposition.

Features of atopic dermatitis in children with oxalic acid dysmetabolism

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T.V. Stoieva

2018-03-01

Full Text Available The article presents the features of atopic dermatitis in children with concomitant metabolic disturbances of oxalic acid. The influence of metabolic shifts was evaluated by clinical presentation, morphofunctional parameters of the skin and the features of oxalic acid metabolites excretion. In this study, a high incidence of dysmetabolic changes was identified, their significance was determined by the involvement of different systems for oxalic acid products excretion. The increased concentration of oxalate in the urine and in the exhaled air condensate had irritant effect and is associated with the hereditary metabolic disorders, early manifestation of atopy symptoms and the intensity of skin itching, with moderate increase of immunoglobulin E level.

Novel Inorganic Coordination Polymers Based on Cadmium Oxalates

Science.gov (United States)

Prasad, P. A.; Neeraj, S.; Vaidhyanathan, R.; Natarajan, Srinivasan

2002-06-01

Three new cadmium oxalate coordination polymers, I-III, with extended layered structures have been synthesized in the presence of imidazole. While I was prepared by the reaction between imidazolium oxalate and Cd, II and III were synthesized from their constituents using hydrothermal methods. [Cd(C2O4)(C3N2H4)]∞ (I): monoclinic, space group P21/c (no. 14), a=8.7093(1) Å, b=9.9477(3) Å, c=8.4352 Å, β=93.796(1)°, Z=4; [Cd(C2O4)2(C3N2H4)3(H2O)]∞ (II): monoclinic, space group P21/c (no. 14), a=7.8614(2) Å, b=14.9332(3) Å, c=15.9153(4) Å β=94.587(1)°, Z=4; [Cd(C2O4)2(C3N2H4)3(H2O)]∞ (III): monoclinic, space group P21/c (no. 14), a=11.844(2) Å, b=9.066(1) Å, c=18.583(2) Å, β=103.84(2)°, Z=4. While the structure of I is made from CdO5N distorted octahedra linked with oxalate, II and III are built-up from CdO6N, CdO5N2 distorted pentagonal bi-pyramids connected to oxalate units. The framework formulas of II and III are identical and their structures closely related. In all the cases, the networking between the Cd-O/N polyhedra and oxalates give rise to layered architectures with the amine molecules pointing in a direction perpendicular to the layers (in the inter-lamellar region). The difference in the linkages between the oxalates and the Cd atoms in I-III, produces unusual Cd-O-Cd one-dimensional chains, which have been observed for the first time.

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.

Urinary oxalate excretion, as determined by isotope dilution and indirect colorimetry

International Nuclear Information System (INIS)

Prenen, J.A.C.; Boer, P.; Leersum, L. van; Oldenburg, S.J.; Endeman, H.J.

1983-01-01

A simple and reliable method for the determination of urinary oxalate excretion is described. Urinary oxalate is precipitated with calcium chloride, and the oxalate content of the precipitate is measured by an indirect colorimetric method developed by Neas and Guyon in 1972. For single urine samples, a correction is made for the incompleteness of the precipitation of calcium oxalate by isotope dilution. The range of normal values (5% limits) determined in 52 normal subjects was 0.121-0.325 mmol.24 h - 1 .m - 2 for a 1-day collection period and 0.145-0.301 mmol. 24 h - 1 .m - 2 for a 3-day collection period. The within-assay CV of a control urine with a low oxalate concentration was 9% (n=7) and the between-assay CV for the same control urine was 12% (n=6). When the values obtained for oxalate excretion were normalized to body surface area, there was no significant difference between males and females; the main source of variation was the intra-individual variation. (Auth.)

Availability of calcium from chemically pure potassium oxalate to the buffalo (Bubalus bubalis)

International Nuclear Information System (INIS)

Singh, Sudarshan; Sareen, V.K.; Marwah, S.R.; Sharma, K.C.; Bhatia, I.S.

1978-01-01

Three experiments were conducted to determine the true dige'stibility of calcium in the buffalo calves fed chemically pure potassium oxalate. In each experiments 6 calves were divided into two groups, viz. control and oxalate-fed. The control group was given basal ration consisting of wheat straw, mustard-cake and maize grains. The oxalate-fed group was fed the basal ration supplemented with 60, 100 and 140 g potassium oxalate per day in experiments 1,2, and 3 respectively. The percent true digestibility of calcium was 51.7 and 52.5 in experiment 1, 60.5 and 44.1 in experiment 2, and 59.3 and 44.1 in experiment 3 in the control and oxalate-fed groups respectively. In all the experiments the oxalate was completely broken down in the rumen. The volume of water intake and urine excretion was more in the oxalate-fed groups. The daily alkali output in the urine in terms of N-acid was 0.7 and 1.3 in experiment 1, 1.5 and 2.5 in experiment 2, and 2.1 and 3.8 in experiment 3 in control and oxalate-fed groups respectively. The daily bicarbonate concentration in the urine (in g) was 26.5 and 53.4 in experiment 1, 83.2 and 146.2 in experiment 2, and 132.6 and 222.8 in experiment 3 in control and oxalate-fed groups respectively. Likewise the excretion of oxalate in the urine was more in oxalate-fed groups. On the basis of the results obtained, the reason for the somewhat low true digestibility of calcium in the calves consuming more than 60 g of potassium oxalate/day are discussed. Isotope-dilution technique using 45 CaCl 2 was employed in the study. (auth.)

Unusual calcium oxalate crystals in ethylene glycol poisoning.

Science.gov (United States)

Godolphin, W; Meagher, E P; Sanders, H D; Frohlich, J

1980-06-01

A patient poisoned with ethylene glycol exhibited the symptoms of (1) hysteria, (2) metabolic acidosis with both a large anion gap and osmolal gap, and (3) crystalluria. However, the shape of the urinary crystals was prismatic and resembled hippurate rather than the expected dipyramidal calcium oxalate dihydrate. X-ray crystallography positively identified them as calcium oxalate monohydrate.

Crystallization of calcium oxalate in minimally diluted urine

Science.gov (United States)

Bretherton, T.; Rodgers, A.

1998-09-01

Crystallization of calcium oxalate was studied in minimally diluted (92%) urine using a mixed suspension mixed product crystallizer in series with a Malvern particle sizer. The crystallization was initiated by constant flow of aqueous sodium oxalate and urine into the reaction vessel via two independent feed lines. Because the Malvern cell was in series with the reaction vessel, noninvasive measurement of particle sizes could be effected. In addition, aliquots of the mixed suspension were withdrawn and transferred to a Coulter counter for crystal counting and sizing. Steady-state particle size distributions were used to determine nucleation and growth kinetics while scanning electron microscopy was used to examine deposited crystals. Two sets of experiments were performed. In the first, the effect of the concentration of the exogenous sodium oxalate was investigated while in the second, the effect of temperature was studied. Calcium oxalate nucleation and growth rates were found to be dependent on supersaturation levels inside the crystallizer. However, while growth rate increased with increasing temperature, nucleation rates decreased. The favored phases were the trihydrate at 18°C, the dihydrate at 38° and the monohydrate at 58°C. The results of both experiments are in agreement with those obtained in other studies that have been conducted in synthetic and in maximally diluted urine and which have employed invasive crystal counting and sizing techniques. As such, the present study lends confidence to the models of urinary calcium oxalate crystallization processes which currently prevail in the literature.

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

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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.

Correlation between oxalic acid production and copper tolerance in Wolfiporia cocos

Science.gov (United States)

C. A. Clausen; Frederick Green; B. M. Woodward; J. W. Evans; R. C. DeGroot

2000-01-01

The increased interest in copper-based wood preservatives has hastened the need for understanding why some fungi are able to attack copper-treated wood. Due in part to accumulation of oxalic acid by brown-rot fungi and visualization of copper oxalate crystals in wood decayed by known copper-tolerant decay fungi, oxalic acid has been implicated in copper tolerance by...

Synthesis, Structure and Thermal Behavior of Oxalato-Bridged Rb+ and H3O+ Extended Frameworks with Different Dimensionalities

Science.gov (United States)

Kherfi, Hamza; Hamadène, Malika; Guehria-Laïdoudi, Achoura; Dahaoui, Slimane; Lecomte, Claude

2010-01-01

Correlative studies of three oxalato-bridged polymers, obtained under hydrothermal conditions for the two isostructural compounds {Rb(HC2O4)(H2C2O4)(H2O)2}∞1, 1, {H3O(HC2O4)(H2C2O4).2H2O}∞1, 2, and by conventional synthetic method for {Rb(HC2O4)}∞3, 3, allowed the identification of H-bond patterns and structural dimensionality. Ferroïc domain structures are confirmed by electric measurements performed on 3. Although 2 resembles one oxalic acid sesquihydrate, its structure determination doesn’t display any kind of disorder and leads to recognition of a supramolecular network identical to hybrid s-block series, where moreover, unusual H3O+ and NH4+ similarity is brought out. Thermal behaviors show that 1D frameworks with extended H-bonds, whether with or without a metal center, have the same stability. Inversely, despite the dimensionalities, the same metallic intermediate and final compounds are obtained for the two Rb+ ferroïc materials.

Effects of Juice Processing on Oxalate Contents in Carambola Juice Products.

Science.gov (United States)

Huynh, Nha K; Nguyen, Ha V H

2017-09-01

Effects of processing methods including pressing, enzyme-assisted extraction, lactic acid fermentation by Lactobacillus acidophilus, and alcohol fermentation by Saccharomyces cerevisiae on total and soluble oxalate contents of carambola juices were studied. In comparison with pressing, the use of enzyme increased juice yields (15.89-17.29%), but resulted in higher total oxalate (1.60-1.73 times) and soluble oxalate contents (1.16-1.49 times). In addition, extension of enzyme incubation periods led to an increase in soluble oxalate contents in the products (p carambola juices. These results suggested that carambola juice products should only be consumed moderately, and that alcohol fermentation could be a potential method to reduce oxalate contents in foods in order to prevent the risks of forming kidney stones.

Studies on the decomposition of oxalic acid by nitric acid in presence of catalysts

International Nuclear Information System (INIS)

Noronha, D.M.; Pius, I.C.; Chaudhury, S.

2015-01-01

Impure Plutonium oxalate generated from the recovery of plutonium from waste solutions may require further purification via anion exchange. Conventionally, plutonium oxalate is converted to oxide in a furnace and the oxide is dissolved in Conc. HNO 3 containing HF and purified by anion exchange route. Studies initiated on the decomposition of oxalic acid with Conc. HNO 3 to facilitate direct dissolution of plutonium oxalate and quantitative destruction of oxalate are discussed in this paper. (author)

Optimization of precipitation conditions of thorium oxalate precipitate

International Nuclear Information System (INIS)

Pazukhin, Eh.M.; Smirnova, E.A.; Krivokhatskij, A.S.; Pazukhina, Yu.L.; Kiselev, P.P.

1986-01-01

Thorium precipitation in the form of difficultly soluble oxalate has been investigated. The equation binding the concentration of metal with the nitric acid in the initial solution and quantity of a precipitator necessary for minimization of desired product losses is derived. The graphical solution of this equation for a case, when the oxalic acid with 0.78 mol/l concentration is the precipitator, is presented

Aspects of calcium oxalate crystallization: theory, in vitro studies, and in vivo implementation.

Science.gov (United States)

Rodgers, A

1999-11-01

There are three main approaches to urolithiasis research: theory, basic science, and clinical implementation. Although each approach has yielded meaningful results, there does not appear to be complete synergy between them. This article examines these approaches as they pertain to urinary calcium oxalate crystallization processes. Theoretical calculations were performed to examine the role of oxalate concentration on calcium oxalate supersaturation. The effects of magnesium, citrate, and combinations thereof on calcium oxalate crystallization kinetics were examined in a mixed suspension, mixed product removal crystallizer. Finally, male volunteers were given supplements of calcium alone and binary combinations of calcium, magnesium, and citrate to investigate their effects on the urinary supersaturation of calcium oxalate. Calculations showed that oxalate is 23 times more potent than calcium in its effect on the supersaturation of calcium oxalate. In the in vitro experiments, magnesium and citrate reduced the growth and nucleation kinetics as well as the supersaturation. In combination, these two components were more effective than the individual components in reducing the growth rate and the supersaturation. All of the supplements favorably altered the kinetic and thermodynamic risk factors. Calcium was the most effective in reducing the urinary excretion of oxalate. Articulation of these three approaches is essential for the meaningful investigation and understanding of urolithiasis.

Preparation of High-purity Indium Oxalate Salt from Indium Scrap by Organic Acids

International Nuclear Information System (INIS)

Koo, Su-Jin; Ju, Chang-Sik

2013-01-01

Effect of organic acid on the preparation of indium-oxalate salt from indium scraps generated from ITO glass manufacturing process was studied. Effects of parameters, such as type and concentration of organic acids, pH of reactant, temperature, reaction time on indium-oxalate salt preparation were examined. The impurity removal efficiency was similar for both oxalic acid and citric acid, but citric acid did not make organic acid salt with indium. The optimum conditions were 1.5 M oxalic acid, pH 7, 80 .deg. C, and 6 hours. On the other hand, the recoveries increased with pH, but the purity decreased. The indium-oxalate salt purity prepared by two cycles was 99.995% (4N5). The indium-oxalate salt could be converted to indium oxide and indium metal by substitution reaction and calcination

Wu-Ling-San formula prophylaxis against recurrent calcium oxalate ...

African Journals Online (AJOL)

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 ...

Oxalate Encapsulation in Aqueous Medium by Tripodal Urea ...

Indian Academy of Sciences (India)

1H-NMR titration studies: All 1H-NMR titration experiments for L1 and L2 were conducted on a Bruker 300 MHz spectrometer at 298 K respectively. Potassium oxalate dihydrate (K2C2O4.2H2O) was used to prepare the stock solution of anion in DMSO-d6:D2O (1:1.1) solvent system. Lower solubility of potassium oxalate in ...

Hydrothermal synthesis and characterization of a binuclear complex and a coordination

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Reza Mohamadinasab

2010-06-01

Full Text Available Two new copper complexes [(bipy(pydcCu(μ-OCO-pydcCu(bipy(H2O].3.5H¬2O (1 and {[(μ2-C2O4(2,2'-bipyCu].2H2O}n (2 (pydcH2 = pyridine-2,6-dicarboxylilic acid, bipy = 2,2'-bipyridine have been hydrothermally synthesized. Both complexes were characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction studies. Complex 1 consists of two independent neutral molecules. In every moiety, metal ion center is in a distorted octahedral geometry. Coordination polymer (2 has been prepared from the reaction of bis-(cyclohexanone-oxal-dihydrazone,2,2'-bipyridine and Cu(NO32 in basic solution and under hydrothermal condition. The results showed that the bis-(cyclohexanone-oxal-dihydrazone was converted to oxalate ion under heating and basic pH. Each metal ion center in 2 is in a distorted octahedral geometry and is coordinated by four oxygen atoms of two bridged oxalate ions and two nitrogen atoms of 2,2'-bipyridine molecules. In the crystal structure of 2, some H-bonds and π-π interaction cause formation of a 3D network.

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] < 1.035), and in 83%, USG was < 1.030. Koalas with oxalate nephrosis were hyperoxaluric compared with Queensland koalas (P < .01). Urinary crystals from 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 < 1.030 (n = 7). Unaffected Mount Lofty Ranges and Kangaroo Island koalas were hyperoxaluric compared with Queensland koalas (P < .01). 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.

NDA technique for the assay of wet plutonium oxalate

International Nuclear Information System (INIS)

Marshall, R.S.; Canada, T.R.

1980-01-01

A method has been developed to quantitatively measure batches of wet plutonium oxalate. The method is based on a count of coincidence neutrons to which a correction is applied for the effects of neutron moderation by water. A therma-neutron coincidence counter (TNC) with two concentric rings of 3 He detectors provides the signal needed for the water correction. The signal is the ratio of neutron counts between the detector rings that changes with the percent of water in plutonium oxalate. To evaluate the measurement technique, 26 batches of plutonium oxalate were measured in an in-line TNC. The evaluation showed the measurements to be essentially unbiased and precise to 2.2%

Interaction Studies of Dilute Aqueous Oxalic Acid

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Kiran Kandpal

2007-01-01

Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

Dynamic process model of a plutonium oxalate precipitator. Final report

Energy Technology Data Exchange (ETDEWEB)

Miller, C.L.; Hammelman, J.E.; Borgonovi, G.M.

1977-11-01

In support of LLL material safeguards program, a dynamic process model was developed which simulates the performance of a plutonium (IV) oxalate precipitator. The plutonium oxalate precipitator is a component in the plutonium oxalate process for making plutonium oxide powder from plutonium nitrate. The model is based on state-of-the-art crystallization descriptive equations, the parameters of which are quantified through the use of batch experimental data. The dynamic model predicts performance very similar to general Hanford oxalate process experience. The utilization of such a process model in an actual plant operation could promote both process control and material safeguards control by serving as a baseline predictor which could give early warning of process upsets or material diversion. The model has been incorporated into a FORTRAN computer program and is also compatible with the DYNSYS 2 computer code which is being used at LLL for process modeling efforts.

Dynamic process model of a plutonium oxalate precipitator. Final report

International Nuclear Information System (INIS)

Miller, C.L.; Hammelman, J.E.; Borgonovi, G.M.

1977-11-01

In support of LLL material safeguards program, a dynamic process model was developed which simulates the performance of a plutonium (IV) oxalate precipitator. The plutonium oxalate precipitator is a component in the plutonium oxalate process for making plutonium oxide powder from plutonium nitrate. The model is based on state-of-the-art crystallization descriptive equations, the parameters of which are quantified through the use of batch experimental data. The dynamic model predicts performance very similar to general Hanford oxalate process experience. The utilization of such a process model in an actual plant operation could promote both process control and material safeguards control by serving as a baseline predictor which could give early warning of process upsets or material diversion. The model has been incorporated into a FORTRAN computer program and is also compatible with the DYNSYS 2 computer code which is being used at LLL for process modeling efforts

Characterization of oxalate-based 237NpO2 powder

International Nuclear Information System (INIS)

Rankin, D.T.; Burney, G.A.; Smith, P.K.; Sisson, R.D.

1976-01-01

238 Pu, a radioisotope heat source, is produced by irradiating reactor targets containing 237 NpO 2 . The neptunium oxide is obtained by precipitating and calcining 237 Np(IV) oxalate. The effects of oxalate precipitation parameters on particle morphology and size distribution of 237 NpO 2 powder were established to provide process controls for fabricating reactor targets

Ultrastructural and biochemical studies on formation of calcium oxalate in plants

International Nuclear Information System (INIS)

Abdelmottaleb, A.M.

1989-01-01

Plant calcium oxalate crystals occur within cells called crystal idioblasts. Important aspects of this calcification phenomenon have not been characterized. This dissertation examines some of the aspects of this ubiquitous type of calcification including (1) characterization of ultrastructural features of developing crystal idioblasts, (2) determination of the relationship of specialized ultrastructural features of the idioblasts to transport of compounds and mechanisms of crystal deposition, and (3) the biochemical relationship between ascorbic acid metabolism and production of oxalic acid used for crystal formation. Structural and cytochemical studies revealed that crystal idioblasts have dense cytoplasm, modified plastids, enlarged nuclei, extensive endoplasmic reticulum, numerous dictyosomes and vesicles, and a bundle of raphide crystals in their vacuoles. A mechanism for Ca transport and crystal precipitation is proposed, based on these results. There is a strong and dynamic relationship between Ca concentration and oxalic acid produced for crystal formation, where increasing Ca level in the growth medium lead to increased total and insoluble oxalate in the plant. Calmodulin antagonists reduced oxalic acid production

Corrosion and impedance studies on magnesium alloy in oxalate solution

International Nuclear Information System (INIS)

Fekry, A.M.; Tammam, Riham H.

2011-01-01

Highlights: → Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na 2 C 2 O 4 containing different additives as Br - , Cl - or Silicate. → The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. → For the other added ions Br - or Cl - , the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br - , Cl - or SiO 3 2- ) on the electrochemical behavior of magnesium alloy in 0.1 M Na 2 C 2 O 4 solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br - or Cl - , the corrosion rate is higher than the blank.

Oxalate complexation in dissolved carbide systems

International Nuclear Information System (INIS)

Choppin, G.R.; Bokelund, H.; Valkiers, S.

1983-01-01

It has been shown that the oxalic acid produced in the dissolution of mixed uranium, plutonium carbides in nitric acid can account for the problems of incomplete uranium and plutonium extraction on the Purex process. Moreover, it was demonstrated that other identified products such as benzene polycarboxylic acids are either too insoluble or insufficiently complexing to be of concern. The stability constants for oxalate complexing of UO 2 +2 and Pu +4 ions (as UO 2 (C 2 O 4 ), Pu(C 2 O 4 ) 2+ and Pu(C 2 O 4 ) 2 , respectively) were measured in nitrate solutions of 4.0 molar ionic strength (0-4 M HNO 3 ) by extraction of these species with TBP. (orig.)

Studies on removal of plutonium from oxalic acid containing hydrochloric acid solutions

Energy Technology Data Exchange (ETDEWEB)

Ghadse, D R; Noronha, D M; Joshi, A R [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Solution containing hydrochloric acid, oxalic acid and considerable quantities of plutonium may be generated while recycling of scrap produced during the metallic fuel fabrication. Plutonium from such waste is normally recovered by anion exchange method after the destruction of oxalic acid using suitable oxidising agent. Solvent extraction and ion exchange methods are being explored in this laboratory for recovery of Pu from oxalic acid containing HCl solutions without prior destruction of oxalic acid. This paper describes the results on the determination of distribution ratios for extraction of Pu(IV) from hydrochloric acid using Aliquot-336 or HDEHP under varying experimental conditions. (author). 5 refs., 5 tabs.

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

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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

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.

Synthesis and colloidal properties of anisotropic hydrothermal barium titanate

Science.gov (United States)

Yosenick, Timothy James

2005-11-01

Nanoparticles of high dielectric constant materials, especially BaTiO3, are required to achieve decreased layer thickness in multilayer ceramic capacitors (MLCCs). Tabular metal nanoparticles can produce thin metal layers with low surface roughness via electrophoretic deposition (EPD). To achieve similar results with dielectric layers requires the synthesis and dispersion of tabular BaTiO3 nanoparticles. The goal of this study was to investigate the deposition of thin BaTiO3 layers using a colloidal process. The synthesis, interfacial chemistry and colloidal properties of hydrothermal BaTiO3 a model particle system, was investigated. After characterization of the material system particulates were deposited to form thin layers using EPD. In the current study, the synthesis of BaTiO3 has been investigated using a hydrothermal route. TEM and AFM analyses show that the synthesized particles are single crystal with a majority of the particle having a zone axis and {111} large face. The particles have a median thickness of 5.8 +/- 3.1 nm and face diameter of 27.1 +/- 12.3 nm. Particle growth was likely controlled by the formation of {111} twins and the synthesis pH which stabilizes the {111} face during growth. With limited growth in the direction, the particles developed a plate-like morphology. Physical property characterization shows the powder was suitable for further processing with high purity, low hydrothermal defect concentration, and controlled stoichiometry. TEM observations of thermally treated powders indicate that the particles begin to loose the plate-like morphology by 900 °C. The aqueous passivation, dispersion, and doping of nanoscale BaTiO 3 powders was investigated. Passivation BaTiO3 was achieved through the addition of oxalic acid. The oxalic acid selectively adsorbs onto the particle surface and forms a chemically stable 2-3 nm layer of barium oxalate. The negative surface charge of the oxalate effectively passivated the BaTiO3 providing a surface

Probable functions of calcium oxalate crystals in different tissues of ...

African Journals Online (AJOL)

Representatives of seven major edible aroid accessions were screened for calcium oxalate using standard histochemical methods. All the accessions were noted to contain calcium oxalate in the forms of raphide bundles and intra-amylar crystals. The crystals were widely present in all parts of the plants including spongy ...

Catalytic upgrading of oleic acid into biofuel using Mo modified zeolite supported Ni oxalate catalyst functionalized with fluoride ion

International Nuclear Information System (INIS)

Ayodele, O.B.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

2014-01-01

Highlights: • Modification of zeolite with freshly prepared molybdenum oxalate. • Functionalization of Ni oxalate with HF and incorporation into Mo modified zeolite. • Characterization of synthesized Mo modified zeolite supported Ni oxalate catalyst. • Deoxygenation of oleic acid with the synthesized zeolite supported catalyst. • Reusability study on the synthesized zeolite supported catalyst. - Abstract: In this study, fluoride ion functionalized nickel oxalate supported on molybdenum modified zeolite (NiMoFOx/Zeol) catalyst was synthesized, characterized and tested on the hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic fuel. The NiMoFOx/Zeol characterization results confirmed the presence of both Ni and Mo as well as the formation of NiMoO 4 which is a highly HDO reactive specie at 2θ value of 43.6° according to the XRD result. NiMoFOx/Zeol also showed loss in crystallinity and reduction in the average particle size leading to increase in the pore volume and specific surface area due to the combined effects of fluoride ion presence, oxalic acid functionalization and calcination. The effect of temperature, pressure and NiMoFOx/Zeol loading studied showed that initial increase in their values increased the yield of the target fractions until some points where reduction was observed. The best observed experimental conditions to hydrodeoxygenate 40 g (∼45 mL) of OA into 75% n-C 18 and 23% i-C 18 were 360 °C, 30 mg NiMoFOx/Zeol loading and 20 bar using 100 mL H 2 /min. The presence of i-C 18 was due to the functionalization of the catalyst with fluoride ion. The catalyst reusability result displayed excellent qualities with marginal loss of only 2% in activity after third reuse due to the improved synthesis protocol that employed organometallic precursor. The results are strongly encouraging for further studies toward industrialization of HDO process

(Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

OpenAIRE

Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

2014-01-01

The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the ox...

Successful treatment of sodium oxalate induced urolithiasis with Helichrysum flowers.

Science.gov (United States)

Onaran, Metin; Orhan, Nilüfer; Farahvash, Amirali; Ekin, Hasya Nazlı; Kocabıyık, Murat; Gönül, İpek Işık; Şen, İlker; Aslan, Mustafa

2016-06-20

Helichrysum (Asteraceae) flowers, known as "altın otu, yayla çiçeği, kudama çiçeği" , are widely used to remove kidney stones and for their diuretic properties in Turkey. To determine the curative effect of infusions prepared from capitulums of Helichrysum graveolens (M. Bieb.) Sweet (HG) and H. stoechas ssp. barellieri (Ten.) Nyman (HS) on sodium oxalate induced kidney stones. Infusions prepared from the capitulums of HG and HS were tested for their curative effect on calcium oxalate deposition induced by sodium oxalate (70mg/kg i.p.). Following the injection of sodium oxalate for 5 days, plant extracts were administered to rats at two different doses. Potassium citrate was used as positive control. Water intake, urine volume, body, liver and kidney weights were measured; biochemical and hematological analyses were conducted on urine and blood samples. Additionally, histopathological examinations were done on kidney samples. H. stoechas extract showed prominent effect at 156mg/kg dose (stone formation score: 0.33), whereas number of kidney stones was maximum in sodium oxalate group (stone formation score: 2.33). The reduction in the uric acid and oxalate levels of urine samples and the elevation in the urine citrate levels are significant and promising in extract groups. Some hematological, biochemical and enzymatic markers are also ameliorated by the extracts. This is the first report on the curative effect of immortal flowers. Our preliminary study indicated that Helichrysum extracts may be used for treatment of urolithiasis and Helichrysum extracts are an alternative therapy to potassium citrate for patients suffering from kidney stones. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Enhanced Chemical Cleaning: Effectiveness Of The UV Lamp To Decompose Oxalates

International Nuclear Information System (INIS)

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

2010-01-01

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

Measurement of plutonium oxalate in thermal neutron coincidence counters

International Nuclear Information System (INIS)

Marshall, R.S.; Erkkila, B.H.

1979-01-01

A coincidence neutron counting method has been developed for assaying batches of plutonium oxalate. Using counting data from two concentric rings of 3 He detectors, corrections are made for the effects that water has on the coincidence neutron count rate. Batches of plutonium oxalate varying from 750 to 1000 g of plutonium and from 34 to 54% water are assayed with an average accuracy of +-3%

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.

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.

Corrosion and impedance studies on magnesium alloy in oxalate solution

Energy Technology Data Exchange (ETDEWEB)

Fekry, A.M., E-mail: hham4@hotmail.com [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt); Tammam, Riham H. [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt)

2011-06-15

Highlights: > Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na{sub 2}C{sub 2}O{sub 4} containing different additives as Br{sup -}, Cl{sup -} or Silicate. > The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. > For the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br{sup -}, Cl{sup -} or SiO{sub 3}{sup 2-}) on the electrochemical behavior of magnesium alloy in 0.1 M Na{sub 2}C{sub 2}O{sub 4} solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank.

Precipitation of plutonium (III) oxalate and calcination to plutonium oxide

International Nuclear Information System (INIS)

Esteban, A.; Orosco, E.H.; Cassaniti, P.; Greco, L.; Adelfang, P.

1989-01-01

The plutonium based fuel fabrication requires the conversion of the plutonium nitrate solution from nuclear fuel reprocessing into pure PuO2. The conversion method based on the precipitation of plutonium (III) oxalate and subsequent calcination has been studied in detail. In this procedure, plutonium (III) oxalate is precipitated, at room temperature, by the slow addition of 1M oxalic acid to the feed solution, containing from 5-100 g/l of plutonium in 1M nitric acid. Before precipitation, the plutonium is adjusted to trivalent state by addition of 1M ascorbic acid in the presence of an oxidation inhibitor such as hydrazine. Finally, the precipitate is calcinated at 700 deg C to obtain PuO2. A flowsheet is proposed in this paper including: a) A study about the conditions to adjust the plutonium valence. b) Solubility data of plutonium (III) oxalate and measurements of plutonium losses to the filtrate and wash solution. c) Characterization of the obtained products. Plutonium (III) oxalate has several potential advantages over similar conversion processes. These include: 1) Formation of small particle sizes powder with good pellets fabrication characteristics. 2) The process is rather insensitive to most process variables, except nitric acid concentration. 3) Ambient temperature operations. 4) The losses of plutonium to the filtrate are less than in other conversion processes. (Author) [es

Arthritis associated with calcium oxalate crystals in an anephric patient treated with peritoneal dialysis

International Nuclear Information System (INIS)

Rosenthal, A.; Ryan, L.M.; McCarty, D.J.

1988-01-01

The authors report a case of calcium oxalate arthropathy in a woman undergoing intermittent peritoneal dialysis who was not receiving pharmacologic doses of ascorbic acid. She developed acute arthritis, with calcium oxalate crystals in Heberden's and Bouchard's nodes, a phenomenon previously described in gout. Intermittent peritoneal dialysis may be less efficient than hemodialysis in clearing oxalate, and physicians should now consider calcium oxalate-associated arthritis in patients undergoing peritoneal dialysis who are not receiving large doses of ascorbic acid

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.

Ruthenium-catalyzed intramolecular metathesis of dienes and its application in the synthesis of bridged and spiro azabicycles

Science.gov (United States)

Kuznetsov, N. Yu; Bubnov, Yu N.

2015-07-01

The review presents a historical excursion into catalytic alkene metathesis, covering the problems of history of the discovery of this process, as well as investigations on the properties, structure and reactivity of the most popular ruthenium catalysts for metathesis, mechanism of their action and decomposition. The main part covers studies devoted to the syntheses of bridged azabicyclic and 1-azaspirocyclic compounds comprising the intramolecular metathesis of dienes as the key step. The formation of a bicyclic skeleton of a series of natural bridged (cocaine, ferruginine, calystegines, and anatoxin-a) and spiro (pinnaic acids, halichlorine, hystrionicotoxin, and cephalotaxine) azabicycles, as well as their analogues and compounds with larger rings is demonstrated. The methods for the synthesis of diene precursors and the conditions for final assembling of the bicyclic compounds are considered in detail. The generalization of the literature data allows one to efficiently carry out the mentioned process taking into account the most important features. The bibliography includes 129 references.

Ruthenium-catalyzed intramolecular metathesis of dienes and its application in the synthesis of bridged and spiro azabicycles

International Nuclear Information System (INIS)

Kuznetsov, N Yu; Bubnov, Yu N

2015-01-01

The review presents a historical excursion into catalytic alkene metathesis, covering the problems of history of the discovery of this process, as well as investigations on the properties, structure and reactivity of the most popular ruthenium catalysts for metathesis, mechanism of their action and decomposition. The main part covers studies devoted to the syntheses of bridged azabicyclic and 1-azaspirocyclic compounds comprising the intramolecular metathesis of dienes as the key step. The formation of a bicyclic skeleton of a series of natural bridged (cocaine, ferruginine, calystegines, and anatoxin-a) and spiro (pinnaic acids, halichlorine, hystrionicotoxin, and cephalotaxine) azabicycles, as well as their analogues and compounds with larger rings is demonstrated. The methods for the synthesis of diene precursors and the conditions for final assembling of the bicyclic compounds are considered in detail. The generalization of the literature data allows one to efficiently carry out the mentioned process taking into account the most important features. The bibliography includes 129 references

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-...

(Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

Science.gov (United States)

Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

2014-01-01

The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°). In the crystal, the components are connected by strong O—H⋯O and much weaker N—H⋯O hydrogen bonds, leading to the formation of layers extending parallel to (001). The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio. PMID:24765013

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.

Influence of oxalic acid on the dissolution kinetics of manganese oxide

Science.gov (United States)

Godunov, E. B.; Artamonova, I. V.; Gorichev, I. G.; Lainer, Yu. A.

2012-11-01

The kinetics and electrochemical processes of the dissolution of manganese oxides with various oxidation states in sulfuric acid solutions containing oxalate ion additives is studied under variable conditions (concentration, pH, temperature). The parameters favoring a higher degree of the dissolution of manganese oxides in acidic media are determined. The optimal conditions are found for the dissolution of manganese oxides in acidic media in the presence of oxalate ions. The mechanism proposed for the dissolution of manganese oxides in sulfuric acid solutions containing oxalic acid is based on the results of kinetic and electrochemical studies. The steps of the dissolution mechanism are discussed.

Lipid synthesis under hydrothermal conditions by Fischer-Tropsch-type reactions.

Science.gov (United States)

McCollom, T M; Ritter, G; Simoneit, B R

1999-03-01

Ever since their discovery in the late 1970's, mid-ocean-ridge hydrothermal systems have received a great deal of attention as a possible site for the origin of life on Earth (and environments analogous to mid-ocean-ridge hydrothermal systems are postulated to have been sites where life could have originated or Mars and elsewhere as well). Because no modern-day terrestrial hydrothermal systems are free from the influence of organic compounds derived from biologic processes, laboratory experiments provide the best opportunity for confirmation of the potential for organic synthesis in hydrothermal systems. Here we report on the formation of lipid compounds during Fischer-Tropsch-type synthesis from aqueous solutions of formic acid or oxalic acid. Optimum synthesis occurs in stainless steel vessels by heating at 175 degrees C for 2-3 days and produces lipid compounds ranging from C2 to > C35 which consist of n-alkanols, n-alkanoic acids, n-alkenes, n-alkanes and alkanones. The precursor carbon sources used are either formic acid or oxalic acid, which disproportionate to H2, CO2 and probably CO. Both carbon sources yield the same lipid classes with essentially the same ranges of compounds. The synthesis reactions were confirmed by using 13C labeled precursor acids.

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

Precipitation stripping of neodymium from carboxylate extractant with aqueous oxalic acid solutions

International Nuclear Information System (INIS)

Konishi, Yasuhiro; Asai, Satoru; Murai, Tetuya

1993-01-01

This paper describes a precipitation stripping method in which neodymium ions are stripped from carboxylate extractant in organic solvent and simultaneously precipitated with aqueous oxalic acid solution. For the single-stage process, a quantitative criterion for precipitating oxalate powders was derived theoretically, and stripping experiments were done under the precipitation conditions. The resultant precipitates were neodymium oxalate, which is completely free from contamination by the carboxylate extractant and the organic solvent. The overall rate of stripping was controlled by the transfer of neodymium carboxylate in the organic solution, indicating that the presence of oxalic acid in the aqueous phase has no effect on the stripping rate. These findings demonstrate the feasibility of combining the conventional stripping and precipitation stages in a solvent extraction process for separation and purification of rare earths

Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

International Nuclear Information System (INIS)

Kasar, U.M.; Pawar, S.M.; Joshi, A.R.

1999-01-01

An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO 3 ) 3 . Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

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.

Determination of Food Oxalates Using Silica–Titania Xerogel Modified with Eriochrome Cyanine R

Directory of Open Access Journals (Sweden)

Maria A. Morosanova

2018-03-01

Full Text Available The interaction of silica–titania xerogel with triphenylmethane dyes (pyrocatechol violet, chrome azurol S, eriochrome cyanine R has been investigated to create a new sensor material for solid phase spectrophotometric determination of food oxalates. The complex forming reaction between xerogel incorporated titanium(IV and triphenylmethane dyes has been studied; half-reaction periods, complex composition, equilibrium constants, and xerogel sorption capacity have been calculated for each dye. Eriochrome cyanine R (ECR is characterized by the shortest half-reaction period, the smallest equilibrium constant, and the greatest capacity; it has been chosen for the sensor material construction because titanium(IV-ECR complex is formed faster and can be destroyed easier than other studied complexes. The interaction of this sensor material with oxalates has been described: the presence of oxalates causes sensor material discoloration and the absorbance is used as analytical signal. The analytical range is 35–900 mg/L (LOD 10.5 mg/L, n = 7. High concentrations of interfering inorganic anions, organic acids, and sucrose did not affect oxalate determination. Proposed solid phase spectrophotometric procedure has been successfully applied for the determination of oxalates in food samples (sorrel, spinach, parsley, ginger, and black pepper and the results are in good agreement with HPLC oxalate determination.

Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.

Science.gov (United States)

Silva, S M A; Malacarne-Zanon, J; Carvalho, R M; Alves, M C; De Goes, M F; Anido-Anido, A; Carrilho, M R

2012-01-01

The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; padhesive, the treatment with potassium oxalate reduced the adhesives' KHN (psystem exhibiting the lowest KHN compared with the MP and SB systems.

Hydrothermal synthesis of a layered-type W-Ti-O mixed metal oxide and its solid acid activity

NARCIS (Netherlands)

Murayama, T.; Nakajima, K.; Hirata, J.; Omata, K.; Hensen, E.J.M.; Ueda, W.

2017-01-01

A layered-type W–Ti–O mixed oxide was synthesized by hydrothermal synthesis from an aqueous solution of ammonium metatungstate and titanium sulfate. To avoid the formation of titania, oxalic acid was used as a reductant. Optimized synthesis led to rod-like particles comprised of MO6 (M = W, Ti)

Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease.

Science.gov (United States)

Marangella, M; Bianco, O; Martini, C; Petrarulo, M; Vitale, C; Linari, F

1989-04-01

Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.

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...

In situ ligand synthesis with the UO22+ cation under hydrothermal conditions

International Nuclear Information System (INIS)

Frisch, Mark; Cahill, Christopher L.

2007-01-01

A novel uranium (VI) coordination polymer, (UO 2 ) 2 (C 2 O 4 )(C 5 H 6 NO 3 ) 2 (1), has been prepared under the hydrothermal reaction of uranium nitrate hexahydrate and L-pyroglutamic acid. Compound 1 (monoclinic, C2/c, a=22.541(6) A, b=5.7428(15) A, c=15.815(4) A, β=119.112(4) o , Z=4, R 1 =0.0237, wR 2 =0.0367) consists of uranium pentagonal bipyramids linked via L-pyroglutamate and oxalate anions to form an overall two-dimensional (2D) structure. With the absence of oxalic acid within the starting materials, the oxalate anions are hypothesized to form in situ whereby decarboxylation of L-pyroglutamic acid occurs followed by coupling of CO 2 to form the oxalate linkages as observed in the crystal structure. Addition of copper (II) to this system appears to promote oxalate formation in that synthetic moolooite (Cu(C 2 O 4 ).nH 2 O; 0≤n≤1) and a known uranyl oxalate [(UO 2 ) 2 (C 2 O 4 )(OH) 2 (H 2 O) 2 .H 2 O], co-crystallize in significant quantity. Compound 1 exhibits the characteristic uranyl emission spectrum upon either direct uranyl excitation or ligand excitation, the latter of which shows an increase in relative intensity. This subsequent increase in the intensity indicates an energy transfer from the ligand to the uranyl cations thus illustrating an example of the antenna effect in the solid state. - Graphical abstract: A novel homometallic coordination polymer (UO 2 ) 2 (C 2 O 4 )(C 5 H 6 NO 3 ) 2 , in the uranium-L-pyroglutamic acid system has been synthesized under hydrothermal conditions. The title compound consists of uranium pentagonal bipyramids bridged through both L-pyroglutamate and oxalate linkages to produce a 3D crystal structure. The oxalate anions are theorized to result from decarboxylation of L-pyroglutamic acid followed by subsequent coupling of CO 2

trans-Methylpyridine cyclen versus cross-bridged trans-methylpyridine cyclen. Synthesis, acid-base and metal complexation studies (metal = Co2+, Cu2+, and Zn2+).

Science.gov (United States)

Bernier, Nicolas; Costa, Judite; Delgado, Rita; Félix, Vítor; Royal, Guy; Tripier, Raphaël

2011-05-07

The synthesis of the cross-bridged cyclen CRpy(2) {4,10-bis((pyridin-2-yl)methyl)-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane}, a constrained analogue of the previously described trans-methylpyridine cyclen Cpy(2) is reported. The additional ethylene bridge confers to CRpy(2) proton-sponge type behaviour which was explored by NMR and potentiometric studies. Transition metal complexes have been synthesized (by complexation of both ligands with Co(2+), Cu(2+) and Zn(2+)) and characterized in solution and in the solid state. The single crystal X-ray structures of [CoCpy(2)](2+), [CuCpy(2)](2+) and [ZnCpy(2)](2+) complexes were determined. Stability constants of the complexes, including those of the cross-bridged derivative, were determined using potentiometric titration data and the kinetic inertness of the [CuCRpy(2)](2+) complex in an acidic medium (half-life values) was evaluated by spectrophotometry. The pre-organized structure of the cross-bridged ligand imposes an additional strain for the complexation leading to complexes with smaller thermodynamic stability in comparison with the related non-bridged ligand. The electrochemical study involving cyclic voltammetry underlines the importance of the ethylene cross-bridge on the redox properties of the transition metal complexes.

Viscosities of oxalic acid and its salts in water and binary aqueous ...

Indian Academy of Sciences (India)

Unknown

Viscosities; oxalic acid and its salts; water + THF mixtures; structure-breakers. 1. Introduction ... has found its application in the organic syntheses as manifested from ... water. In other words, these results indicate that oxalic acid and its salts mix ...

Effect of processing and cooking on total and soluble oxalate content in frozen root vegetables prepared for consumption

Directory of Open Access Journals (Sweden)

Z. LISIEWSKA

2008-12-01

Full Text Available The oxalate content of beetroot, carrot, celeriac and parsnip after freezing by traditional and modified methods (the latter resulting in a convenience food product, and after the preparation of frozen products for consumption was evaluated. The highest content of total and soluble oxalates (105 and 82 mg 100 g-1 fresh matter was found in beetroot. The lowest proportion (55% of soluble oxalates was noted in celeriac; this proportion was higher in the remaining vegetables, being broadly similar for each of them. Blanching brought about a significant decrease in total and soluble oxalates in fresh vegetables. Cooking resulted in a higher loss of oxalates. The level of oxalates in products prepared for consumption directly after freezing approximated that before freezing. Compared with the content before freezing, vegetables prepared for consumption by cooking after frozen storage contained less oxalates, except for total oxalates in parsnip and soluble oxalates in beetroot and celeriac. The highest ratio of oxalates to calcium was found in raw beetroot; it was two times lower in raw carrot; five times lower in raw celeriac; and eight times lower in raw parsnip. These ratios were lower after technological and culinary processing. The percentage of oxalate bound calcium depended on the species; this parameter was not significantly affected by the procedures applied. The true retention of oxalates according to Judprasong et al. (2006 was lower than retention calculated taking its content in 100 g fresh matter into account.;

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...

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Tetraphenylphosphonium hydrogen oxalate

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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°.

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

Adaptable coordination of U(IV) in the 2D-(4,4) uranium oxalate network: From 8 to 10 coordinations in the uranium (IV) oxalate hydrates

International Nuclear Information System (INIS)

Duvieubourg-Garela, L.; Vigier, N.; Abraham, F.; Grandjean, S.

2008-01-01

Crystals of uranium (IV) oxalate hydrates, U(C 2 O 4 ) 2 .6H 2 O (1) and U(C 2 O 4 ) 2 .2H 2 O (2), were obtained by hydrothermal methods using two different U(IV) precursors, U 3 O 8 oxide and nitric U(IV) solution in presence of hydrazine to avoid oxidation of U(IV) into uranyl ion. Growth of crystals of solvated monohydrated uranium (IV) oxalate, U(C 2 O 4 ) 2 .H 2 O.(dma) (3), dma=dimethylamine, was achieved by slow diffusion of U(IV) into a gel containing oxalate ions. The three structures are built on a bi-dimensional complex polymer of U(IV) atoms connected through bis-bidentate oxalate ions forming [U(C 2 O 4 )] 4 pseudo-squares. The flexibility of this supramolecular arrangement allows modifications of the coordination number of the U(IV) atom which, starting from 8 in 1 increases to 9 in 3 and, finally increases, to 10 in 2. The coordination polyhedron changes from a distorted cube, formed by eight oxygen atoms of four oxalate ions, in 1, to a mono-capped square anti-prism in 3 and, finally, to a di-capped square anti-prism in 2, resulting from rotation of the oxalate ions and addition of one and two water oxygen atoms in the coordination of U(IV). In 1, the space between the ∞ 2 [U(C 2 O 4 ) 2 ] planar layers is occupied by non-coordinated water molecules; in 2, the space between the staggered ∞ 2 [U(C 2 O 4 ) 2 .2H 2 O] layers is empty, finally in 3, the solvate molecules occupy the interlayer space between corrugated ∞ 2 [U(C 2 O 4 ) 2 .H 2 O] sheets. The thermal decomposition of U(C 2 O 4 ) 2 .6H 2 O under air and argon atmospheres gives U 3 O 8 and UO 2 , respectively. - Graphical abstract: The adaptable environment of U(IV) in U(IV) oxalates: from eight cubic coordination in U(C 2 O 4 ) 2 .6H 2 O (a) completed by water oxygens to nine in [U(C 2 O 4 ) 2 .H 2 O](C 2 NH 5 ) (b) and ten coordination in U(C 2 O 4 ) 2 .2H 2 O (c)

The production of (14C) oxalate during the metabolism of (14C) carbohydrates in isolated rat hepatocytes.

Science.gov (United States)

Rofe, A M; James, H M; Bais, R; Edwards, J B; Conyers, R A

1980-04-01

Oxalate (14C) was produced during the metabolism of (U-14C) carbohydrates in hepatocytes isolated from normal rats. At 10 mM, the order of oxalate production was fructose > glycerol > xylitol > sorbitol greater than or equal to glucose in the ratio 10 : 4 : 3 : 1 : 1. This difference between oxalate production from fructose and glucose was reflected in their rates of utilisation, glucose being poorly metabolised in hepatocytes from fasted rats. Fructose was rapidly metabolised, producing glucose, lactate and pyruvate as the major metabolites. Glycerol, xylitol and sorbitol were metabolised at half the rate of fructose, the major metabolites being glucose, lactate and glycerophosphate. The marked similarity in the pattern of intermediary metabolites produced by these polyols was not, however, reflected in the rates of oxalate production. Hepatic polyol metabolism resulted in high levels of cytosolic NADH, as indicated by elevated lactate : pyruvate and glycerophosphate : dihydroxyacetone phosphate ratios. The artificial electron acceptor, phenazine methosulphate (PMS) stimulated oxalate production from the polyols, particularly xylitol. In the presence of PMS, the order of oxalate production was fructose greater than or equal to xylitol > glycerol > sorbitol in the ratio 10 : 10 : 6 : 2. The production of glucose, lactate and pyruvate from the polyols was also stimulated by PMS, whereas the general metabolism of fructose, including oxalate production, was little affected. Oxalate (14C) was produced from (1-14C), (2-14C) and (6-14C) but not (3,4-14C) glucose in hepatocytes isolated from non-fasted, pyridoxine-deficient rats. Whilst this labelling pattern is consistent with oxalate being produced by a number of pathways, it is suggested that metabolism via hydroxypyruvate is a major route for oxalate production from various carbohydrates, with perhaps the exception of xylitol, which appears to have an alternative mechanism for oxalate production. The observation that

Intramolecular Diels–Alder reaction as a key step in tandem or sequential processes: a versatile tool for the synthesis of fused and bridged bicyclic or polycyclic compounds.

Digital Repository Service at National Institute of Oceanography (India)

Parvatkar, P.T.; Kadam, H.K.; Tilve, S.G.

This review summarizes the recent examples of tandem or sequential reactions used for the last 10 years for the synthesis of fused and bridged bicyclic or polycyclic compounds with IMDA cycloaddition as the key means to access these compounds...

Acute oxalate nephropathy due to ′Averrhoa bilimbi′ fruit juice ingestion

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G Bakul

2013-01-01

Full Text Available Irumban puli (Averrhoa bilimbi is commonly used as a traditional remedy in the state of Kerala. Freshly made concentrated juice has a very high oxalic acid content and consumption carries a high risk of developing acute renal failure (ARF by deposition of calcium oxalate crystals in renal tubules. Acute oxalate nephropathy (AON due to secondary oxalosis after consumption of Irumban puli juice is uncommon. AON due to A. bilimbi has not been reported before. We present a series of ten patients from five hospitals in the State of Kerala who developed ARF after intake of I. puli fruit juice. Seven patients needed hemodialysis whereas the other three improved with conservative management.

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.

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.

Crystal structure of dimethylammonium hydrogen oxalate hemi(oxalic acid

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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.

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

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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.

Complexation of Am(III) by oxalate in NaClO4 media

International Nuclear Information System (INIS)

Choppin, G.R.; Chen, J.F.

1995-01-01

The complexation of Am(III) by oxalate has been investigated in solutions of NaClO 4 up to 9.0 M ionic strength at 25 degrees C. The dissociation constants of oxalic acid were determined by potentiometric titration, while the stability constants of the Am(III)-oxalate complexation were measured by the solvent extraction technique. A thermodynamic model was constructed to predict the apparent equilibrium constants at different ionic strengths by applying the Pitzer equation using parameters for the Na + -HOx - , Na + -Ox - , AmOx + -ClO 4 - , and Na + -Am(Ox) 2 - interactions obtained by fitting the data

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 A novel method has been developed for determining soluble and insoluble forms of oxalate in pulp and paper samples by ion chromatography. Methanesulphonic acid is used to dissolve insoluble oxalate, and total oxalate is then determined by ion...

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.

Calcium extraction from brine water and seawater using oxalic acid

Science.gov (United States)

Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

2017-01-01

Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

Crystal forms of the hydrogen oxalate salt of o-desmethylvenlafaxine.

Science.gov (United States)

Dichiarante, Elena; Curzi, Marco; Giaffreda, Stefano L; Grepioni, Fabrizia; Maini, Lucia; Braga, Dario

2015-06-01

To prepare new crystalline forms of the antidepressant o-desmethylvenlafaxine salt as potential new commercial forms and evaluate their physicochemical properties, in particular the dissolution rate. A new hydrogen oxalate salt of o-desmethylvenlafaxine hydrogen oxalate (ODV-OX) was synthesized, and a polymorph screening was performed using different solvents and crystallization conditions. Crystalline forms were characterized by a combination of solid-state techniques: X-ray powder diffraction, differential scanning calorimetry, thermogravimetric analysis, FT-IR spectroscopy and single crystal X-ray diffraction. The stability of all crystalline phases was tested under International Conference on Harmonisation (ICH) conditions (40°C and 75% Relative Humidity (RH)) for 1 week. Dissolution tests were performed on the hydrogen oxalate salt ODV-OX Form 1 and compared with dissolution test on the commercial form of the succinate salt of o-desmethylvenlafaxine. Five crystalline forms of ODV-OX were isolated, namely three hydrated forms (Form 1, Form 2, Form 3) and two anhydrous forms (Form 4 and Form 5). Comparative solubility tests on ODV-OX Form 1 and o-desmethylvenlafaxine succinate evidenced a significant increase in solubility for the hydrogen oxalate salt (142 g/l) with respect to the succinate salt (70 g/l). © 2015 Royal Pharmaceutical Society.

Behaviour of Pu-IV with various ion exchangers in solutions containing nitric acid and oxalates

International Nuclear Information System (INIS)

Walter, E.; Ali, S.A.

1982-02-01

The distribution of Pu-IV on the ion exchangers Dowex 50W-X8, Dowex 1-X8 und Dowex Chelating Resin Al-X8 in the presence of various concentrations of nitric acid and oxalate were investigated. The results indicate that nitric acid and oxalic acid influence each other during complexation of Pu-IV with oxalate ions solutions containing nitric acid it is not possible to neglect the formation of Pu-IV nitrate complexes. The complex Pu(IV) (C 2 O 4 ) 3 2 - only is formed in solutions containing low nitric acid and high oxalic acid concentrations. The separation of Pu-IV in Dowex Chelating Resin from nitric acid solution in the presence of higher oxalate concentrations is possible, provided that the nitric acid concentration is lower than 0.25 molar [fr

Effect of oxalic acid on the optical, thermal, dielectric and mechanical behaviour of ADP crystals

International Nuclear Information System (INIS)

Rajesh, P.; Ramasamy, P.

2009-01-01

The effect of the addition, over a concentration range from 1 to 5 mol%, of oxalic acid on the growth rate, optical transparency, hardness, dielectric behaviour, and SHG efficiency of ammonium dihydrogen phosphate single crystals grown by slow evaporation method has been investigated. UV-Vis studies show that the transparency of the oxalic acid added crystals decreased gradually. Thermal studies indicate that the decomposition temperatures of the crystal are decreased in oxalic acid added ADP crystals. It is observed from the dielectric measurements that the dielectric constant and dielectric loss increase with increase in temperature for all the crystals. Vicker's microhardness study reveals that the addition of higher concentration of oxalic acid decreases the hardness of the crystal. SHG efficiency of 1 mol% of oxalic acid is higher than the pure ADP.

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

International Nuclear Information System (INIS)

Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, Francois; 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 x 10 4 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

EFFECTIVENESS OF USING DILUTE OXALIC ACID TO DISSOLVE HIGH LEVEL WASTE IRON BASED SLUDGE SIMULANT

International Nuclear Information System (INIS)

Ketusky, E

2008-01-01

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

Two novel 3-D bismuth oxalates with organic amines protruding in channels

International Nuclear Information System (INIS)

Yu Xiaohong; Zhang Hanhui; Cao Yanning; Hu Zhongjian; Chen Yiping; Wang Zhen

2006-01-01

Two novel 3-D oxalate-containing bismuth compounds of formula (C 3 N 2 H 5 ) 2 [Bi 2 (C 2 O 4 ) 4 (H 2 O) 2 ].2H 2 O 1 and [NH(C 2 H 5 ) 3 ][Bi 3 (C 2 O 4 ) 5 ] 2 were obtained by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic P2/n space group with a=9.7541(13)A, b=17.7404(15)A, c=14.6321(6)A, β=97.280(3) o , Z=4, R 1 =0.0340 and wR 2 =0.0766 for unique 4734 reflections I>2σ(I). Compound 2 belongs to the orthorhombic Pbcn space group with a=14.803(4)A, b=19.783(7)A, c=8.202(2)A, Z=4, R 1 =0.0222 and wR 2 =0.0568 for unique 2472 reflections I>2σ(I). The Bi III centers have nine-fold coordination for 1 and eight-fold for 2 with the Bi atoms in distorted monocapped square antiprism and distorted dodecahedron, respectively. And oxalate ligands adopt different coordination modes: bidentate for 1, bidentate and tricoordinate for 2. Compounds 1 and 2 are both 3-D open-framework structures containing channels with guest molecules. These two compounds exhibit intense blue luminescence with the emission peaks at 419nm for 1 and 442nm for 2, respectively, in the solid state at room temperature. These compounds with novel structural frameworks could be useful in the field of photoactive materials

Intercomparison of the measurements of oxalic acid in aerosols by gas chromatography and ion chromatography

Science.gov (United States)

Kawamura, Kimitaka; Barrie, Leonard A.; Toom-Sauntry, Desiree

2010-12-01

Oxalate, the anion of oxalic acid, is one of the most abundant measurable organic species in atmospheric aerosols. Traditionally, this bifunctional species has been measured by gas chromatography (GC) after derivatization to butyl ester and by ion chromatography (IC) without derivatization. However, there are few published comparisons of the two techniques. Here, we report the results of an intercomparison study for the measurement of oxalic acid in Arctic aerosols (oxalic acid by GC ranged from 6.5-59.1 ng m -3 (av. 26.0 ng m -3, median 26.2 ng m -3) whereas those by IC ranged from 6.6-52.1 ng m -3 (av. 26.6 ng m -3, median 25.4 ng m -3). They showed a good correlation ( r = 0.84) with a slope of 0.96. Thus, observations of oxalate obtained by GC employing dibutyl esters are almost equal to those by IC. Because the accuracy of oxalic acid by GC method largely depends on the method used, it is important to strictly examine the recovery in each study.

Towards novel efficient and stable nuclear import signals: synthesis and properties of trimethylguanosine cap analogs modified within the 5',5'-triphosphate bridge.

Science.gov (United States)

Zytek, Malgorzata; Kowalska, Joanna; Lukaszewicz, Maciej; Wojtczak, Blazej A; Zuberek, Joanna; Ferenc-Mrozek, Aleksandra; Darzynkiewicz, Edward; Niedzwiecka, Anna; Jemielity, Jacek

2014-12-07

A trimethylguanosine (TMG) cap is present at the 5' end of several small nuclear and nucleolar RNAs. Recently, it has been reported that the TMG cap is a potential nuclear import signal for nucleus-targeting therapeutic nucleic acids and proteins. The import is mediated by recognition of the TMG cap by the snRNA transporting protein, snurportin1. This work describes the synthesis and properties of a series of dinucleotide TMG cap (m3(2,2,7)GpppG) analogs modified in the 5',5'-triphosphate bridge as tools to study TMG cap-dependent biological processes. The bridge was altered at different positions by introducing either bridging (imidodiphosphate, O to NH and methylenebisphosphonate, O to CH2) or non-bridging (phosphorothioate, O to S and boranophosphate, O to BH3) modifications, or by elongation to tetraphosphate. The stability of novel analogs in blood serum was studied to reveal that the α,β-bridging O to NH substitution (m3(2,2,7)GppNHpG) confers the highest resistance. Short RNAs capped with analogs containing α,β-bridging (m3(2,2,7)GppNHpG) or β-non-bridging (m3(2,2,7)GppSpG D2) modifications were resistant to decapping pyrophosphatase, hNudt16. Preliminary studies on binding by human snurportin1 revealed that both O to NH and O to S substitutions support this binding. Due to favorable properties in all three assays, m3(2,2,7)GppNHpG was selected as a promising candidate for further studies on the efficiency of the TMG cap as a nuclear import signal.

Evidence of a natural marine source of oxalic acid and a possible link to glyoxal

Science.gov (United States)

Rinaldi, Matteo; Decesari, Stefano; Carbone, Claudio; Finessi, Emanuela; Fuzzi, Sandro; Ceburnis, Darius; O'Dowd, Colin D.; Sciare, Jean; Burrows, John P.; Vrekoussis, Mihalis; Ervens, Barbara; Tsigaridis, Kostas; Facchini, Maria Cristina

2011-08-01

This paper presents results supporting the existence of a natural source of oxalic acid over the oceans. Oxalate was detected in "clean-sector" marine aerosol samples at Mace Head (Ireland) (53°20'N, 9°54'W) during 2006, and at Amsterdam Island (37°48'S, 77°34'E) from 2003 to 2007, in concentrations ranging from 2.7 to 39 ng m-3 and from 0.31 to 17 ng m-3, respectively. The oxalate concentration showed a clear seasonal trend at both sites, with maxima in spring-summer and minima in fall-winter, being consistent with other marine biogenic aerosol components (e.g., methanesulfonic acid, non-sea-salt sulfate, and aliphatic amines). The observed oxalate was distributed along the whole aerosol size spectrum, with both a submicrometer and a supermicrometer mode, unlike the dominant submicrometer mode encountered in many polluted environments. Given its mass size distribution, the results suggest that over remote oceanic regions oxalate is produced through a combination of different formation processes. It is proposed that the cloud-mediated oxidation of gaseous glyoxal, recently detected over remote oceanic regions, may be an important source of submicrometer oxalate in the marine boundary layer. Supporting this hypothesis, satellite-retrieved glyoxal column concentrations over the two sampling sites exhibited the same seasonal concentration trend of oxalate. Furthermore, chemical box model simulations showed that the observed submicrometer oxalate concentrations were consistent with the in-cloud oxidation of typical marine air glyoxal mixing ratios, as retrieved by satellite measurements, at both sites.

Polyfunctional inorganic-organic hybrid materials: an unusual kind of NLO active layered mixed metal oxalates with tunable magnetic properties and very large second harmonic generation.

Science.gov (United States)

Cariati, Elena; Macchi, Roberto; Roberto, Dominique; Ugo, Renato; Galli, Simona; Casati, Nicola; Macchi, Piero; Sironi, Angelo; Bogani, Lapo; Caneschi, Andrea; Gatteschi, Dante

2007-08-01

Mixed M(II)/M(III) metal oxalates, as "stripes" connected through strong hydrogen bonding by para-dimethylaminobenzaldeide (DAMBA) and water, form an organic-inorganic 2D network that enables segregation in layers of the cationic organic NLO-phore trans-4-(4-dimethylaminostyryl)-1-methylpyridinium, [DAMS+]. The crystalline hybrid materials obtained have the general formula [DAMS]4[M2M'(C2O4)6].2DAMBA.2H2O (M = Rh, Fe, Cr; M' = Mn, Zn), and their overall three-dimensional packing is non-centrosymmetric and polar, therefore suitable for second harmonic generation (SHG). All the compounds investigated are characterized by an exceptional SHG activity, due both to the large molecular quadratic hyperpolarizability of [DAMS+] and to the efficiency of the crystalline network which organizes [DAMS+] into head-to-tail arranged J-type aggregates. The tunability of the pairs of metal ions allows exploiting also the magnetic functionality of the materials. Examples containing antiferro-, ferro-, and ferri-magnetic interactions (mediated by oxalato bridges) are obtained by coupling proper M(III) ions (Fe, Cr, Rh) with M(II) (Mn, Zn). This shed light on the role of weak next-nearest-neighbor interactions and main nearest-neighbor couplings along "stripes" of mixed M(II)/M(III) metal oxalates of the organic-inorganic 2D network, thus suggesting that these hybrid materials may display isotropic 1D magnetic properties along the mixed M(II)/M(III) metal oxalates "stripes".

Uranyl oxalate hydrates: structures and IR spectra

International Nuclear Information System (INIS)

Giesting, P.A.; Porter, N.J.; Burns, P.C.

2006-01-01

The novel compound (UO 2 ) 2 C 2 O 4 (OH) 2 (H 2 O) 2 (UrOx2A) and the previously studied compound UO 2 C 2 O 4 (H 2 O) 3 (UrOx3) have been synthesized by mild hydrothermal methods. Single crystal diffraction data collected at 125 K using MoK α radiation and a CCD-based area detector were used to solve and refine the crystal structures by full-matrix least-squares techniques to agreement indices (UrOx2A, UrOx3) wR 2 = 0.037, 0.049 for all data, and R1 0.015, 0.024 calculated for 1285, 2194 unique reflections respectively. The compound UrOx2A is triclinic, space group P1, Z = 1, a = 5.5353(4), b 6.0866(4), c = 7.7686(6) Aa, α = 85.6410(10) , β = 89.7740(10) , γ = 82.5090(10) , V = 258.74(3) Aa 3 . The compound UrOx3 is monoclinic, space group P2 1 /c, Z = 4, a = 5.5921(4), b = 16.9931(13), c = 9.3594(7) Aa, β = 99.5330(10) , V = 877.11(11) Aa 3 . The structures consist of chains of uranyl pentagonal bipyramids connected by oxalate groups and, in UrOx2A, hydroxyl groups; UrOx2A is also notable for its high (2:1) ratio of uranyl to oxalate groups, higher than any observed in other published structures of uranyl oxalates. The structure determined for UrOx3, previously studied by Jayadevan and Chackraburtty (1972); Mikhailov et al. (1999) is in agreement with the previous results; however, the increased precision of the present low-temperature structure refinement allows for the assignment of H atom positions based on the difference Fourier map of electron density. The infrared spectra of these two materials collected at room temperature are also presented and compared with previous work on uranyl oxalate systems. (orig.)

an oxalate-peroxide complex used in the preparation of doped barium titanate

NARCIS (Netherlands)

van der Gijp, S.; Winnubst, Aloysius J.A.; Verweij, H.

1998-01-01

A method is described for the preparation of homogeneously doped barium titanate, which can be applied in non-linear dielectric elements. Ba and Ti salts are dissolved, mixed with hydrogen peroxide and added to a solution of ammonium oxalate, resulting in the formation of an insoluble peroxo-oxalate

Hydrazinium lanthanide oxalates: synthesis, structure and thermal reactivity of N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce, Nd.

Science.gov (United States)

De Almeida, Lucie; Grandjean, Stéphane; Rivenet, Murielle; Patisson, Fabrice; Abraham, Francis

2014-03-28

New hydrazinium lanthanide oxalates N2H5[Ln2(C2O4)4(N2H5)]·4H2O, Ln = Ce (Ce-HyOx) and Nd (Nd-HyOx), were synthesized by hydrothermal reaction at 150 °C between lanthanide nitrate, oxalic acid and hydrazine solutions. The structure of the Nd compound was determined from single-crystal X-ray diffraction data, space group P2₁/c with a = 16.315(4), b = 12.127(3), c = 11.430(2) Å, β = 116.638(4)°, V = 2021.4(7) Å(3), Z = 4, and R1 = 0.0313 for 4231 independent reflections. Two distinct neodymium polyhedra are formed, NdO9 and NdO8N, an oxygen of one monodentate oxalate in the former being replaced by a nitrogen atom of a coordinated hydrazinium ion in the latter. The infrared absorption band at 1005 cm(-1) confirms the coordination of N2H5(+) to the metal. These polyhedra are connected through μ2 and μ3 oxalate ions to form an anionic three-dimensional neodymium-oxalate arrangement. A non-coordinated charge-compensating hydrazinium ion occupies, with water molecules, the resulting tunnels. The N-N stretching frequencies of the infrared spectra demonstrate the existence of the two types of hydrazine ions. Thermal reactivity of these hydrazinium oxalates and of the mixed isotypic Ce/Nd (CeNd-HyOx) oxalate were studied by using thermogravimetric and differential thermal analyses coupled with gas analyzers, and high temperature X-ray diffraction. Under air, fine particles of CeO2 and Ce(0.5)Nd(0.5)O(1.75) are formed at low temperature from Ce-HyOx and CeNd-HyOx, respectively, thanks to a decomposition/oxidation process. Under argon flow, dioxymonocyanamides Ln2O2CN2 are formed.

Characterization of metabolic network of oxalic acid biosynthesis through RNA seq data analysis of developing spikes of finger millet (Eleusine coracana): Deciphering the role of key genes involved in oxalate formation in relation to grain calcium accumulation.

Science.gov (United States)

Akbar, Naved; Gupta, Supriya; Tiwari, Apoorv; Singh, K P; Kumar, Anil

2018-04-05

In the present study, we identified seven major genes of oxalic acid biosynthesis pathway (SGAT, GGAT, ICL, GLO, MHAR, APO and OXO) from developing spike transcriptome of finger millet using rice as a reference. Sequence alignment of identified genes showed high similarity with their respective homolog in rice except for OXO and GLO. Transcript abundance (FPKM) reflects the higher accumulation of identified genes in GP-1 (low calcium genotype) as compared to GP-45 (high calcium genotype) which was further confirmed by qRT-PCR analysis, indicating differential oxalate formation in both genotypes. Determination of oxalic acid and tartaric acid content in developing spikes explain that higher oxalic acid content in GP-1 however, tartaric acid content was more in GP-45. Higher calcium content in GP-45 and lower oxalate accumulation may be due to the diversion of more ascorbic acid into tartaric acid and may correspond to less formation of calcium oxalate. Our results suggest that more than one pathway for oxalic acid biosynthesis might be present in finger millet with probable predominance of ascorbate-tartarate pathway rather than glyoxalate-oxalate conversion. Thus, finger millet can be use as an excellent model system for understanding more specific role of nutrients-antinutrients interactions, as evident from the present study. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

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.

[H3N(CH2)4NH3]2[Al4(C2O4)(H2PO4)2(PO4)4].4[H2O]: A new layered aluminum phosphate-oxalate

International Nuclear Information System (INIS)

Peng Li; Li Jiyang; Yu Jihong; Li Guanghua; Fang Qianrong; Xu Ruren

2005-01-01

A new layered inorganic-organic hybrid aluminum phosphate-oxalate [H 3 N(CH 2 ) 4 NH 3 ] 2 [Al 4 (C 2 O 4 )(H 2 PO 4 ) 2 (PO 4 ) 4 ].4[H 2 O](AlPO-CJ25) has been synthesized hydrothermally, by using 1,4-diaminobutane (DAB) as structure-directing agent. The structure has been solved by single-crystal X-ray diffraction analysis and further characterized by IR, 31 P MAS NMR, TG-DTA as well as compositional analyses. Crystal data: the triclinic space group P-1, a=8.0484(7) A, b=8.8608(8) A, c=13.2224(11) A, α=80.830(6) deg. , β=74.965(5) deg. , γ=78.782(6) deg. , Z=2, R 1[ I >2 σ ( I )] =0.0511 and wR 2(alldata) =0.1423. The alternation of AlO 4 tetrahedra and PO 4 tetrahedra gives rise to the four-membered corner-sharing chains, which are interconnected through AlO 6 octahedra to form the layered structure with 4,6-net sheet. Interestingly, oxalate ions are bis-bidentately bonded by participating in the coordination of AlO 6 , and bridging the adjacent AlO 6 octahedra. The layers are held with each other through strong H-bondings between the terminal oxygens. The organic ammonium cations and water molecules are located in the large cavities between the interlayer regions. -- Graphical abstract: The alternation of AlO 4 tetrahedra and PO 4 tetrahedra gives rise to the four-membered corner-sharing chains, which are interconnected through AlO 6 octahedra to form the layered structure with 4,6-net sheet. Oxalate ions are bis-bidentately boned by participating in the coordination of AlO 6 , and bridging the adjacent AlO 6 octahedra

Hydrazinium lanthanide oxalates: synthesis, structure and thermal reactivity of N_2H_5[Ln_2(C_2O_4)_4(N_2H_5)].4H_2O, Ln = Ce, Nd

International Nuclear Information System (INIS)

De Almeida, Lucie; Grandjean, Stephane; Abraham, Francis; Rivenet, Murielle; Patisson, Fabrice

2014-01-01

New hydrazinium lanthanide oxalates N_2H_5[Ln_2(C_2O_4)_4(N_2H_5)].4H_2O, Ln = Ce (Ce-H_yO_x) and Nd (Nd- H_yO_x), were synthesized by hydrothermal reaction at 150 C between lanthanide nitrate, oxalic acid and hydrazine solutions. The structure of the Nd compound was determined from single-crystal X-ray diffraction data, space group P2_1/c with a = 16.315(4), b = 12.127(3), c = 11.430(2) Angstroms, β = 116.638(4) degrees, V = 2021.4(7) Angstroems"3, Z = 4, and R1 = 0.0313 for 4231 independent reflections. Two distinct neodymium polyhedra are formed, NdO_9 and NdO_8N, an oxygen of one monodentate oxalate in the former being replaced by a nitrogen atom of a coordinated hydrazinium ion in the latter. The infrared absorption band at 1005 cm"-"1 confirms the coordination of N_2H_5"+ to the metal. These polyhedra are connected through μ"2 and μ"3 oxalate ions to form an anionic three-dimensional neodymium-oxalate arrangement. A non-coordinated charge-compensating hydrazinium ion occupies, with water molecules, the resulting tunnels. The N-N stretching frequencies of the infrared spectra demonstrate the existence of the two types of hydrazine ions. Thermal reactivity of these hydrazinium oxalates and of the mixed isotypic Ce/Nd (CeNd-H_yO_x) oxalate were studied by using thermogravimetric and differential thermal analyses coupled with gas analyzers, and high temperature X-ray diffraction. Under air, fine particles of CeO_2 and Ce_0_._5Nd_0_._5O_1_._7_5 are formed at low temperature from Ce-H_yO_x and CeNd-H_yO_x, respectively, thanks to a decomposition/oxidation process. Under argon flow, dioxy-mono-cyanamides Ln_2O_2CN_2 are formed. (authors)

Study on the Key Technology of High Purity Strontium Titanate Powder Synthesized from Oxalic Acid Co-sediment Precipitation

Science.gov (United States)

Bi, Xiaoguo; Dong, Yingnan; Li, Yingjie; Niu, Wei; Tang, Jian; Ding, Shuang; Li, Meiyang

2017-09-01

Oxalate coprecipitation is applied in this paper, high purity titanium tetrachloride, and after the purification of strontium chloride, match with a certain concentration of solution, oxalate and strontium chloride and titanium tetrachloride in 1.005:1.000 make strontium titanium mixture ratio, slowly under 60°C to join in oxalic acid solution, aging around 4 h, get oxygen titanium strontium oxalate (SrTiO(C2O4)2 • 4H2 ) precipitation, after washing, drying and other process made oxygen titanium strontium oxalate powder.

ROLE OF THE MICROFLORA IN DISTAL INTESTINAL TRACT BY MAINTAINING OXALATE HOMEOSTASIS

Directory of Open Access Journals (Sweden)

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

Liquid waste processing from plutonium (III) oxalate precipitation

International Nuclear Information System (INIS)

Esteban, A.; Cassaniti, P.; Orosco, E.H.

1990-01-01

Plutonium (III) oxalate filtrates contain about 0.2M oxalic acid, 0.09M ascorbic acid, 0.05M hydrazine, 1M nitric acid and 20-100 mg/l of plutonium. The developed treatment of liquid wastes consist in two main steps: a) Distillation to reduce up to 10% of the initial volume and refluxing to destroy organic material. Then, the treated solution is suitable to adjust the plutonium at the tetravalent state by addition of hydrogen peroxide and the nitric molarity up to 8.6M. b) Recovery and purification of plutonium by anion exchange using two columns in series containing Dowex 1-X4 resin. With the proposed process, it is possible to transform 38 litres of filtrates with 40mg/l of Pu into 0.1 l of purified solution with 15-20g/l of Pu. This solution is suitable to be recycled in the Pu (III) oxalate precipitation process. This process has several potential advantages over similar liquid waste treatments. These include: 1) It does not increase the liquid volume. 2) It consumes only few reagents. 3) The operations involved are simple, requiring limited handling and they are feasible to automatization. 4) The Pu recovery factor is about 99%. (Author) [es

Investigation on clean-up of Zr and HDBP in PUREX process with UDMH oxalate

International Nuclear Information System (INIS)

Zhang Youzhi; Wang Xuanjun; Li Zhengli; Liu Xiangxuan

2007-01-01

It is generally accepted that the interracial crud formation is related to the complex formation of Zr with degradation products of TBP, such as DBP and MBP, in PUREX process, especially in the first cycle. The crud seriously deteriorates the operation of extraction column and therefore must be properly cleared up. Various clear up methods were studied and those with salt-free washing agents were recently focused. In this paper a new scrubbing agent 1,1- dimethylhydrazine (UDMH) oxalate was proposed, the optimized experimental conditions were described, and the possible mechanism was discussed. The influence of different factors, including reaction temperature, UDMH oxalate concentration, organic-to-aqueous phase ratio, and free UDMH concentration, on the decontamination factors were examined with simulated Zr- and/or DBP-loaded solvents. The optical experimental parameters are found as follows: temperature 40-60 degree C, phase ratio V (o) /V (a) =1, concentration of UDMH oxalate solution 0.4-0.6 mol/L. Especialy some UDMH was added into the UDMH oxalate queues solution to make the concentration of free UDMH 0.2-0.3 mol/L. Under these conditions, the decontaminator factor of Zr from the corresponding simulated solvent with UDMH oxalate is up to 143, slightly higher than that with sodium carbonate. The decontamination factor of HDBP from the corresponding simulated solvent with UDMH oxalate is up to 100, similar to sodium carbonate. (authors)

Primary Nonfunction of Renal Allograft Secondary to Acute Oxalate Nephropathy

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Ravi Parasuraman

2011-01-01

Full Text Available Primary nonfunction (PNF accounts for 0.6 to 8% of renal allograft failure, and the focus on causes of PNF has changed from rejection to other causes. Calcium oxalate (CaOx deposition is common in early allograft biopsies, and it contributes in moderate intensity to higher incidence of acute tubular necrosis and poor graft survival. A-49-year old male with ESRD secondary to polycystic kidney disease underwent extended criteria donor kidney transplantation. Posttransplant, patient developed delayed graft function (DGF, and the biopsy showed moderately intense CaOx deposition that persisted on subsequent biopsies for 16 weeks, eventually resulting in PNF. The serum oxalate level was 3 times more than normal at 85 μmol/L (normal <27 μmol/L. Allograft nephrectomy showed massive aggregates of CaOx crystal deposition in renal collecting system. In conclusion, acute oxalate nephropathy should be considered in the differential diagnosis of DGF since optimal management could change the outcome of the allograft.

Improving the two-step remediation process for CCA-treated wood. Part I, Evaluating oxalic acid extraction

Science.gov (United States)

Carol Clausen

2004-01-01

In this study, three possible improvements to a remediation process for chromated-copper-arsenate (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for...

The Relationship between Serum Oxalic Acid, Central Hemodynamic Parameters and Colonization by Oxalobacter formigenes in Hemodialysis Patients.

Science.gov (United States)

Gulhan, Baris; Turkmen, Kultigin; Aydin, Merve; Gunay, Murat; Cıkman, Aytekin; Kara, Murat

2015-06-01

Elevated pulse wave velocity (PWV) and central aortic blood pressures are independent predictors of increased cardiovascular morbidity and mortality in hemodialysis (HD) patients. Oxalic acid is a uremic retention molecule that is extensively studied in the pathogenesis of calcium oxalate stones. Oxalobacter formigenes, a member of the colon microbiota, has important roles in oxalate homeostasis. Data regarding the colonization by and the exact role of O. formigenes in the pathogenesis of oxalic acid metabolism in HD patients are scant. Hence, we aimed to determine the relationship between fecal O. formigenes colonization, serum oxalic acid and hemodynamic parameters in HD patients with regard to the colo-reno-cardiac axis. Fifty HD patients were enrolled in this study. PWV and central aortic systolic (cASBP) and diastolic blood pressures (cADBP) were measured with a Mobil-O-Graph (I.E.M. GmbH, Stolberg, Germany). Serum oxalic acid levels were assessed by ELISA, and fecal O. formigenes DNA levels were isolated and measured by real-time PCR. Isolation of fecal O. formigenes was found in only 2 HD patients. One of them had 113,609 copies/ml, the other one had 1,056 copies/ml. Serum oxalic acid levels were found to be positively correlated with PWV (r = 0.29, p = 0.03), cASBP (r = 0.33, p = 0.001) and cADBP (r = 0.42, p = 0.002) and negatively correlated with LDL (r = -0.30, p = 0.03). In multivariate linear regression analysis, PWV was independently predicted by oxalic acid, glucose and triglyceride. This is the first study that demonstrates the absence of O. formigenes as well as a relation between serum oxalic acid and cASBP, cADBP and PWV in HD patients. Replacement of O. formigenes with pre- and probiotics might decrease serum oxalic acid levels and improve cardiovascular outcomes in HD patients.

Tetrakis(acetonitrilecopper(I hydrogen oxalate–oxalic acid–acetonitrile (1/0.5/0.5

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A. Timothy Royappa

2013-10-01

Full Text Available In the title compound, [Cu(CH3CN4](C2HO4·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four acetonitrile ligands in a slightly distorted tetrahedral environment. The oxalic acid molecule lies across an inversion center. The acetonitrile solvent molecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid molecules are linked via O—H...O hydrogen bonds, forming chains along [010].

Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...

African Journals Online (AJOL)

Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate on the ... The test plant was sown in aluminium-polluted soil (conc. ... The perseverance of the test plant in the aluminium spiked soil is an indication of adaptation to the stress ...

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 composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar....... The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns...

Oxalate content of different drinkable dilutions of tea infusions after different brewing times.

Science.gov (United States)

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

2012-01-01

The aims of this study were to determine the effect of different brewing times and diluting on oxalate content of loose-packed black teas consumed in Tabriz, Iran. The oxalate content of black teas after brewing for 5, 10, 15, 30, 60 minutes was measured in triplicate by enzymatic assay. In order to attain the most acceptable dilution of tea infusions, tea samples which were brewed for 15, 30 and 60 minutes were diluted two (120 ml), three (80 ml) and four (60 ml) times respectively. There was a stepwise increase in oxalate concentrations associated with increased brewing times (Pbrewing times, respectively. There were significant differences between the mean oxalate content of different dilutions after brewing for 15, 30 and 60 minutes (Pbrewing times and different dilution was below the recommended levels. Therefore, it seems that consumption of black tea several times per day would not pose significant health risk in kidney stone patients and susceptible individuals.

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.

Isolation and characterization of mesophilic, oxalate-degrading Streptomyces from plant rhizosphere and forest soils

Science.gov (United States)

Sahin, Nurettin

2004-10-01

The present work was aimed at the isolation of additional new pure cultures of oxalate-degrading Streptomyces and its preliminary characterization for further work in the field of oxalate metabolism and taxonomic studies. Mesophilic, oxalate-degrading Streptomyces were enriched and isolated from plant rhizosphere and forest soil samples. Strains were examined for cultural, morphological (spore chain morphology, spore mass colour, diffusible and melanin pigment production), physiological (antibiosis, growth in the presence of inhibitory compounds, assimilation of organic acids and enzyme substrates) and chemotaxonomic characters (cellular lipid components and diagnostic cell-wall diamino acid). The taxonomic data obtained were analysed by using the simple matching (SSM) and Jaccard (SJ) coefficients, clustering was achieved using the UPGMA algorithm. All strains were able to utilize sodium-, potassium-, calcium- and ammonium-oxalate salts. Based on the results of numerical taxonomy, isolates were grouped into five cluster groups with a ≥70% SSM similarity level. Streptomyces rochei was the most common of the cluster groups, with a Willcox probability of P>0.8. Streptomyces antibioticus, S. anulatus, S. fulvissimus, S. halstedii and S. violaceusniger are newly reported as oxalate-utilizing Streptomyces.

Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

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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.

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

Science.gov (United States)

Aggarwal, A; Tandon, S; Singla, S K; Tandon, C

2010-01-01

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. 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. 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. 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.

Influencing the solubility of oxalates for the preparation of ceramic powders from mixed precipitates

International Nuclear Information System (INIS)

Krueger, C.; Fischer, S.; Fischer, St.; Chebani, M.Kh.

1991-01-01

Based on investigations of the solubility of oxalate with 140 Ba, 64 Cu and 59 Fe, techniques for quantitative oxalate coprecipitation were developed. Addition of organic solvents lowers the solubility and leads to a smaller particle size of products. (orig.) [de

The oxalic acid biosynthetic activity of Burkholderia mallei is encoded by a single locus

Science.gov (United States)

Although it is known that oxalic acid provides a selective advantage to the secreting microbe, our understanding of how this acid is biosynthesized remains incomplete. This study reports the identification, cloning, and partial characterization of the oxalic acid biosynthetic enzyme from the animal ...

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 <2 years of age. The findings of this study suggest that oxalate nephrosis is a leading disease in this koala population. Possible causes of this disease are currently under investigation.

Synthesis of poly(aniline-co-o-toluidine) coatings on copper

Energy Technology Data Exchange (ETDEWEB)

Raotole, Pritee, E-mail: priteeraotole@gmail.com; Patil, V. T.; Huse, V. R.; Chaudhari, A. L. [MGSM’s Arts, Science and Commerce, College, Chopda, Dist-Jalgaon 425107, Maharashtra (India); Raotole, Mahesh [Sharacchandrika Suresh Patil, Institute of Technology, Polytechnic, Chopda, Dist-Jalgaon, 425107, Maharashtra (India)

2016-05-06

The corrosion protective poly(aniline-co-o-toluidine) (PAOT) coatings were synthesized on copper (Cu) by the electrochemical copolymerization of aniline with o-toluidine under cyclic voltammetry conditions. Aqueous oxalate solutions were used as the supporting electrolytes for the synthesis of PAOT coatings on Cu. The resulting coatings were characterized by different spectroscopic techniques, cyclic voltammetry, ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and scanning electron microscopy. The Fourier Transform InfraRed (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy studies reveal that the copolymerization of aniline and o-toluidine takes place on Cu substrates from an aqueous oxalate solutions and resulting in PAOT copolymer, there are more o-toluidine units than aniline units.

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...

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.

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

Directory of Open Access Journals (Sweden)

Miia R Mäkelä

Full Text Available 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 transcriptional level study on oxalate-catabolising genes was performed with an effective lignin-degrading white-rot fungus Dichomitus squalens, which has demonstrated particular abilities in production and degradation of oxalic acid. The expression of oxalic-acid decomposing oxalate decarboxylase (ODC and formic-acid decomposing formate dehydrogenase (FDH encoding genes was followed during the growth of D. squalens on its natural spruce wood substrate. The effect of high proton concentration on the regulation of the oxalate-catabolising genes was determined after addition of organic acid (oxalic acid and inorganic acid (hydrochloric acid to the liquid cultures of D. squalens. In order to evaluate the co-expression of oxalate-catabolising and manganese peroxidase (MnP encoding genes, the expression of one MnP encoding gene, mnp1, of D. squalens was also surveyed in the solid state and liquid cultures. Sequential action of ODC and FDH encoding genes was detected in the studied cultivations. The odc1, fdh2 and fdh3 genes of D. squalens showed constitutive expression, whereas ODC2 and FHD1 most likely are the main responsible enzymes for detoxification of high concentrations of oxalic and formic acids. The results also confirmed the central role of ODC1 when D. squalens grows on coniferous wood. Phylogenetic analysis revealed that fungal ODCs have evolved from at least two gene copies whereas FDHs have a single ancestral gene. As a conclusion, the multiplicity of oxalate-catabolising genes and their differential regulation on wood and in acid-amended cultures of D. squalens point to divergent physiological roles for the corresponding enzymes.

Continuous plutonium(IV) oxalate precipitation, filtration, and calcination process. [From product streams from Redox, Purex, or Recuplex solvent extraction plants

Energy Technology Data Exchange (ETDEWEB)

Beede, R L

1956-09-27

A continuous plutonium (IV) oxalate precipitation, filtration, and calcination process has been developed. Continuous and batch decomposition of the oxalate in the filtrates has been demonstrated. The processes have been demonstrated in prototype equipment. Plutonium (IV) oxalate was precipitated continuously at room temperature by the concurrent addition of plutonium (IV) nitrate feed and oxalic acid into the pan of a modified rotary drum filter. The plutonium (IV) oxalate was calcined to plutonium dioxide, which could be readily hydrofluorinated. Continuous decomposition of the oxalate in synthetic plutonium (IV) oxalate filtrates containing plutonium (IV) oxalate solids was demonstrated using co-current flow in a U-shaped reactor. Feeds containing from 10 to 100 g/1 Pu, as plutonium (IV) nitrate, and 1.0 to 6.5 M HNO/sub 3/, respectively, can be processed. One molar oxalic acid is used as the precipitant. Temperatures of 20 to 35/sup 0/C for the precipitation and filtration are satisfactory. Plutonium (IV) oxalate can be calcined at 300 to 400/sup 0/C in a screw-type drier-calciner to plutonium dioxide and hydrofluorinated at 450 to 550/sup 0/C. Plutonium dioxide exceeding purity requirements has been produced in the prototype equipment. Advantages of continuous precipitation and filtration are: uniform plutonium (IV) oxalate, improved filtration characteristics, elimination of heating and cooling facilities, and higher capacities through a single unit. Advantages of the screw-type drier-calciner are the continuous production of an oxide satisfactory for feed for the proposed plant vibrating tube hydrofluorinator, and ease of coupling continuous precipitation and filtration to this proposed hydrofluorinator. Continuous decomposition of oxalate in filtrates offers advantages in decreasing filtrate storage requirements when coupled to a filtrate concentrator. (JGB)

Savannah River Site Tank Cleaning: Corrosion Rate For One Versus Eight Percent Oxalic Acid Solution

International Nuclear Information System (INIS)

Ketusky, E.; Subramanian, K.

2011-01-01

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 from

Charge dynamics in conducting polyaniline–metal oxalate composites

Indian Academy of Sciences (India)

Unknown

Polyaniline; metal oxalate composites; charge transport; mobile and fixed spins; VRH conduc- tion mechanism ... Al, Mn and Co on doping into Pani improve the poly- merization ... dopants on charge dynamics with EPR and other tech- niques.

Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

International Nuclear Information System (INIS)

Sun Liang; Qiu Keqiang

2012-01-01

Graphical abstract: Display Omitted Highlights: ► Vacuum pyrolysis as a pretreatment was used to separate cathode material from aluminum foils. ► Cobalt and lithium can be leached using oxalate while cobalt can be directly precipitated as cobalt oxalate. ► Cobalt and lithium can be separated efficiently from each other only in the oxalate leaching process. ► High reaction efficiency of LiCoO 2 was obtained with oxalate. - Abstract: 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.

Substituting milk for apple juice does not increase kidney stone risk in most normocalciuric adults who form calcium oxalate stones.

Science.gov (United States)

Massey, L K; Kynast-Gales, S A

1998-03-01

Increasing intake of dietary calcium from less than 400 mg to 800 mg daily may decrease the absorption of dietary oxalate, which in turn would decrease urinary oxalate excretion. The effect of substituting milk for apple juice on urine composition and risk of calcium oxalate precipitability was studied. Twenty-one normocalciuric adults with a history of at least 1 calcium oxalate stone and urinary oxalate excretion exceeding 275 micromol/day on their self-selected diet. Randomized crossover trial. Each participant consumed two moderate-oxalate (2,011 micromol/day) study diets, which were identical except that one contained 360 mL milk and the other contained 540 mL apple juice as the beverage with meals. Four days free-living then 2 days in the metabolic unit of a university nutrition department. Tiselius risk index for calcium oxalate precipitability calculated from urine composition. Paired t tests. Twenty-four hour urinary oxalate excretion was 18% lower (Pjuice diet: 423 vs 514 micromol, respectively. Calcium excretion was 17% higher (Pjuice diet: 4.7 vs 3.9 mmol, respectively. Urinary magnesium and citrate excretion, volume, and Tiselius risk index did not differ between diets. Substituting 360 mL milk daily for apple juice with meals in a diet containing moderate amounts of dietary oxalate from whole grains, legumes, fruits, and vegetables does not increase the risk index of calcium oxalate precipitability in most normocalciuric adults who form stones.

Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

International Nuclear Information System (INIS)

STALLINGS, MARY

2004-01-01

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

Determining the biochemical properties of the Oxalate Biosynthetic Component (Obc)1 from Burkholderia mallei

Science.gov (United States)

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 quo...

Evaluation of soluble oxalates content in infusions of different kinds of tea and coffee available on the Polish market.

Science.gov (United States)

Rusinek, Elzbieta

2012-01-01

Tea and coffee are the potentially rich source of oxalic acid, which can act as a antinutrient. The aim of this study was to determine and evaluate the content of soluble oxalates in teas and coffees available on the Polish market. The green, red and black teas, and black natural ground and instant coffees were used for preparing the infusions. The manganometric method was used for the determination of the oxalates in the infusions. The mean oxalates content in the infusions from 3 g of black teas was 115.68 mg/100 cm3 and was higher as compared to red teas (101.91 mg/100 cm3) and green teas (87.64 mg/100 cm3). Disregarding the variety of analyzed teas, the largest oxalates content was in infusions of pure one-component tea--"Sir Roger" (164.82-174.22 mg/100 cm3), while the lowest oxalates content was noted in the tea containing the components from other plants ("Bio-Active" with grapefruit juice--reaching as low level as 39.00 mg/100 cm3). Instant coffees contained larger amount of oxalates than natural ground coffees. Irrespective of the kind of the tested coffees, the lowest oxalates content was found in the infusions from the following coffees: Tchibo Exclusive--19.62 mg/100 cm3, Gala ulubiona--37.32 mg/100 cm3, and Maxwell House--38.40 mg/100 cm3, while the highest oxalates content in instant coffee--Nescafe Espiro 51.80 mg/100 cm3. The results revealed a significant relation between phytochemical composition of analyzed teas and coffees and the level of soluble oxalates in infusions prepared from the tested products.

Synthesis of carbon nanotubes bridging metal electrodes

International Nuclear Information System (INIS)

Kotlar, M.; Vojs, M.; Marton, M.; Vesel, M.; Redhammer, R.

2012-01-01

In our work we demonstrate growth of carbon nanotubes that can conductively bridge the metal electrodes. The role of different catalysts was examined. Interdigitated metal electrodes are made from copper and we are using bimetal Al/Ni as catalyst for growth of carbon nanotubes. We are using this catalyst composition for growth of the single-walled carbon nanotube network. (authors)

Studies on Pu(IV)/(III)-oxalate precipitation from nitric acid containing high concentration of calcium and fluoride ions

International Nuclear Information System (INIS)

Kalsi, P.K.; Pawar, S.M.; Ghadse, D.R.; Joshi, A.R.; Ramakrishna, V.V.; Vaidya, V.N.; Venugopal, V.

2003-01-01

Plutonium (IV)/(III) oxalate precipitation from nitric acid solution, containing large amount of calcium and fluoride ions was investigated. It was observed that direct precipitation of Pu (IV) oxalate from nitric acid containing large amount of calcium and fluoride ions did not give good decontamination of Pu from calcium and fluoride impurities. However, incorporation of hydroxide precipitation using ammonium hydroxide prior to Pu (IV) oxalate precipitation results into PuO 2 with much less calcium and fluoride impurities. Whereas, good decontamination from calcium and fluoride impurities could be obtained by employing Pu (III) oxalate precipitation directly from nitric acid containing large amount of calcium and fluoride ions. A method was also developed to recover Pu from the oxalate waste containing calcium and fluoride ions. (author)

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....

Framework for a comprehensive bridge management and information system.

Science.gov (United States)

2011-11-01

"The purpose of this research project was to provide a framework for the development of a Bridge : Management Information System (BMIS). Researchers developed a synthesis of current BMIS development : activities and identified sources of data availab...

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. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

A Systematic Method to Synthesize New Transformerless Full-bridge Grid-tied Inverters

DEFF Research Database (Denmark)

Wang, Hongliang; Burton, Sarah; Liu, Yan-Fei

2014-01-01

Many inverter topologies have been proposed to eliminate the leakage current of transformerless Full Bridge Grid-Tied photovoltaic (PV) inverters. These include implementations such as the H5, H6, and HERIC topologies, among others. In this paper, a new full bridge topology synthesis method, called...... the MN synthesis method, is proposed. The MN method introduces two criteria that can be used to synthesize all of the possible topologies, including the existing topologies as well as new simplified topologies. This method concludes that there are only 15 simplified topologies available. Most simplified...... topologies from MN method have been verified by existing papers and patents....

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.

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.

Circular patterns of calcium oxalate monohydrate induced by defective Langmuir-Blodgett film on quartz substrates

Energy Technology Data Exchange (ETDEWEB)

He Jieyu [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Ouyang Jianming [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)], E-mail: toyjm@jnu.edu.cn

2009-01-01

The defective Langmuir-Blodgett (LB) film of dipalmitoylphosphatidylcholine (DPPC) on quartz injured by potassium oxalate (K{sub 2}C{sub 2}O{sub 4}) was used as a model system to induce growth of calcium oxalate crystals. Atomic force microscopy (AFM) indicated that circular defective domains with a diameter of 1-200 {mu}m existed in the LB film. Scanning electron microscopy (SEM) showed circular patterns of aggregated calcium oxalate monohydrate (COM) crystallites were induced by these defective domains. It was ascribed to that the interaction between the negatively-charged oxalate ions and the phosphatidyl groups in DPPC headgroups makes the phospholipid molecules rearranged and exist in an out-of-order state in the LB film, especially at the boundaries of liquid-condensed (LC)/liquid-expanded (LE) phases, which provide much more nucleating sites for COM crystals.

Effects of dietary interventions on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones

Directory of Open Access Journals (Sweden)

Mustafa Kıraç

2013-02-01

Full Text Available The aim of this study is to investigate the effects of dietary factors on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones. A total of 108 of idiopathic recurrent calcium oxalate stones were included in the study. A 24-hour urinalysis was performed and metabolic abnormalities were measured for all of the patients. All of the patients were given specialized diets for their 24-hour urine abnormalities. At the end of first month, the same parameters were examined in another 24-hour urinalysis. Hyperoxaluria, hypernatruria, and hypercalciuria were found in 84 (77%, 43 (39.8%, and 38 (35.5% of the patients, respectively. The differences between the oxalate, sodium, volume, uric acid, and citrate parameters before and after the dietary intervention were significant (p < 0.05. The calcium parameters were not significantly different before and after the intervention. We found that oxalate, sodium, volume, uric acid, and citrate—but not calcium—abnormalities in patients with recurrent calcium oxalate stones can be corrected by diet. The metabolic profiles of idiopathic calcium oxalate stone patients should be evaluated and the appropriate dietary interventions should be implemented to decrease stone recurrence.

SAFETY EVALUATION OF OXALIC ACID WASTE RETRIEVAL IN SINGLE SHELL TANK (SST) 241-C-106

International Nuclear Information System (INIS)

SHULTZ, M.V.

2003-01-01

This report documents the safety evaluation of the process of retrieving sludge waste from single-shell tank 241-C-106 using oxalic acid. The results of the HAZOP, safety evaluation, and control allocation/decision are part of the report. This safety evaluation considers the use of oxalic acid to recover residual waste in single-shell tank (SST) 241-C-106. This is an activity not addressed in the current tank farm safety basis. This evaluation has five specific purposes: (1) Identifying the key configuration and operating assumptions needed to evaluate oxalic acid dissolution in SST 241-C-106. (2) Documenting the hazardous conditions identified during the oxalic acid dissolution hazard and operability study (HAZOP). (3) Documenting the comparison of the HAZOP results to the hazardous conditions and associated analyzed accident currently included in the safety basis, as documented in HNF-SD-WM-TI-764, Hazard Analysis Database Report. (4) Documenting the evaluation of the oxalic acid dissolution activity with respect to: (A) Accident analyses described in HNF-SD-WM-SAR-067, Tank Farms Final Safety Analysis Report (FSAR), and (B) Controls specified in HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements (TSR). (5) Documenting the process and results of control decisions as well as the applicability of preventive and/or mitigative controls to each oxalic acid addition hazardous condition. This safety evaluation is not intended to be a request to authorize the activity. Authorization issues are addressed by the unreviewed safety question (USQ) evaluation process. This report constitutes an accident analysis

Computational and experimental studies on oxalic acid imprinted ...

Indian Academy of Sciences (India)

e-mail: rkkawadkar@chm.vnit.ac.in. MS received 13 ... vent or porogen to form a pre-polymerization complex, followed by .... tered off and the filtrate was analysed for oxalic acid by. UV/VIS ... The experimental binding data were fitted to the.

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.

Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

International Nuclear Information System (INIS)

Yu Jiaguo; Tang Hua; Cheng Bei; Zhao Xiujian

2004-01-01

Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca 2+ ]/[C 2 O 4 2- ] ratio and concentration of PSMA and CaC 2 O 4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis

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 aluminum in soil by bitter leaf plant (Vernonia ... highest accumulation of aluminium in the root (16.92mg/kg); however concentrations of aluminium in the roots were .... whereas the sulphate was 13.75mg/kg. Table 2: The total colony count of ...

BaTiO3 thick fi lms obtained by tape casting from powders prepared by the oxalate route

Directory of Open Access Journals (Sweden)

Adelina Ianculescu

2009-06-01

Full Text Available BaTiO3 powders were prepared by co-precipitation via oxalate route. The size, morphology and particle size distribution of the oxalate powders have been optimized by the control of different synthesis parameters during the precipitation reaction (nature of salts, concentration of different solutions, aging time. The single phase BaTiO3 oxide particles were obtained after a thermal decomposition of the as-synthesized powders at 850°C for 4 hours under air atmosphere. Oxide powders with a suitable specifi c surface area were selected in order to obtain thick fi lms by the tape casting technique. The microstructure and dielectric properties of the thick films varied obviously depending on the deposition-calcination-sintering cycle used. A double depositioncalcination cycle followed by sintering, as well as a two step deposition-calcination-sintering procedure was used in order to improve the compactness and therefore, the dielectric behaviour. A higher dielectric constant value (~ 750 and lower dielectric losses (~ 2 % were achieved at room temperature and at 1 kHz frequency for the dense, double-deposited fi lm obtained after two deposition-calcination-sintering cycles. For this film, a superior value of the dielectric constant (~ 1100, almost frequency independent in the frequency range of 100 Hz – 10 kHz was gained also at the ferroelectric-paraelectric phase transition temperature of 130°C.

Conductance and bulk vertical detachment energy of hydrated sulphate and oxalate dianions: a theoretical study

Science.gov (United States)

Pathak, Arup Kumar

2014-06-01

Analytical expressions have been derived for the vertical detachment energy (VDE) for hydrated sulphate (SO2 -4) and oxalate (C2O2 -4) dianions that can be used to calculate the same over a wide range of cluster sizes including the bulk from the knowledge of VDE for a finite number of stable clusters. The calculated bulk detachment energies are found to be very good in agreement (within 5%) with the available experimental results for both the systems. It is observed that two or more water molecules will be essential for the stability of sulphate and oxalate dianions against spontaneous electron loss and this is consistent with the experiment. We have, for the first time, provided a scheme to calculate the radius of the solvent berg for sulphate and oxalate dianions. The calculated conductivity values for the sulphate and oxalate dianions using Stokes-Einstein relation and the radius of solvent berg are found to be very good in agreement (within 4%) with the available experimental results.

Utilisation of sugarcane trash and other cellulosic wastes for production of oxalic acid

Energy Technology Data Exchange (ETDEWEB)

Mane, J D; Modak, H M; Ramaiah, N A; Jadhav, S J

1988-01-01

The nitric acid oxidation process was developed for the production of oxalic acid from sugarcane trash, groundnut shells, corn cobs and rice husks. Good yields of oxalic acid from the above raw materials were obtained under optimum conditions, with sugarcane trash as the preferable raw material. The absorption of waste nitrogen oxide gases in aqueous NaOH to get a valuable by-product, sodium nitrite, was also successful.

Growth and physico chemical characterization of lanthanum neodymium oxalate single crystals

International Nuclear Information System (INIS)

Raju, K.S.; John, Varughese; Ittyachen, M.A.

1998-01-01

Single crystals of lanthanum neodymium oxalate (LNO) are grown in sodium meta silicate gels, by the diffusion of a mixture of aqueous solutions of lanthanum nitrate and neodymium nitrate into the test tube having the set gel containing oxalic acid. The bluish pink coloured tabular crystals of LNO having well defined hexagonal basal planes appear either as foggy or clear, the latter at the greater depths inside the gel. The coloration of LNO visually observed is evidenced in UV-visible spectrum, by the revelation of well pronounced characteristic peaks in the visible region (500-900 nm). X-ray diffraction (XRD) of powdered LNO is ordered, meaning crystalline in nature, besides its isostructurality with similarly grown lanthanum samarium oxalate crystals. The single crystallinity of LNO is established by its oscillation XRD pattern. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) support that LNO loses water of crystallization around 120 degC and CO and CO 2 around 350-450 degC, while the infrared absorption (IR) spectrum of LNO establishes the presence of oxalate (C 2 O 4 ) 2- ions. Energy dispersive x-ray analysis (EDAX) confirms the presence of La and Nd in the sample. X-ray photoelectron spectroscopic (XPS) studies of LNO establish the presence of La and Nd in their respective oxide states. An empirical structure for LNO has been proposed on the basis of these findings. The smokiness in the foggy LNO crystal has been attributed due to the gel inclusion during the growth process. (author)

Colorimetric sensing of oxalate based on its inhibitory effect on the reaction of Fe (III) with curcumin nanoparticles

Science.gov (United States)

Pourreza, Nahid; Lotfizadeh, Neda; Golmohammadi, Hamed

2018-03-01

In this research, a new colorimetric method for the determination of oxalate using curcumin nanoparticles (CURNs) in the presence Fe (III) is introduced. The method is based on the inhibitory effect of oxalate ion on the reaction of (CURNs) with Fe (III) in acidic media. This reaction was monitored by measuring the increase in absorbance of CURNs-Fe3 + complex in the presence of oxalate ion at 427 nm. The effect of different parameters such as the pH of the sample solution, concentration of Fe (III), concentration of CURNs and the reaction time was examined and optimized. Under optimum experimental conditions, the absorption intensity was linear with the concentration of oxalate in the range of 0.15 to 1.70 μg mL- 1. The limit of detection (LOD) was 0.077 μg mL- 1 and the relative standard deviations (RSD) for 8 replicate measurements of 0.40 and 1.05 μg mL- 1 of oxalate were 4.20% and 2.74%, respectively. The developed method was successfully employed to the determination of oxalate in water, food and urine samples with satisfactory results.

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

Effect of Lagenaria siceraria fruit powder on sodium oxalate induced urolithiasis in Wistar rats

Directory of Open Access Journals (Sweden)

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.

Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

Science.gov (United States)

Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

2015-01-01

Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

Synthesis and crystal structures of three isophthalato-bridged ...

Indian Academy of Sciences (India)

dral environments, and the isophthalato ligand bridges two Ni(II) centres in a bis bidentate fashion to form dimers in all three complexes. ... building blocks to construct supramolecular isomers, and one-dimensional left-handed helical chains of ... region using KBr pellets and a Bruker. EQUINOX 55 spectrometer. The solid ...

Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

International Nuclear Information System (INIS)

Rudisill, T.S.

1999-01-01

Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

Synthesis of concrete bridge piles prestressed with CFRP systems.

Science.gov (United States)

2017-06-01

The Texas Department of Transportation frequently constructs prestressed concrete piles for use in bridge : foundations. Such prestressed concrete piles are typically built with steel strands that are highly susceptible to : environmental degradation...

Effect of dentin pretreatment with potassium oxalate: analysis of microtensile bond strengths and morphologic aspects.

Science.gov (United States)

De Moraes Porto, Isabel Cristina Celerino; De Andrade, Ana Karina Maciel; Alves, Luiz Carlos; Braz, Rodivan

2012-02-01

An effective and stable bond is the most desirable characteristic of contemporary adhesive systems. The aim of this study was to evaluate the effect of potassium oxalate on dentin/resin bond strength. Dentin on the occlusal surface of human premolars was exposed and etched with 35% phosphoric acid, to receive 3% monohydrated potassium oxalate and the following adhesive systems: Scotchbond Multipurpose (SMO; 3M/ESPE) and Prime & Bond NT (PBO; Dentsply), followed by the application of resin composite (Z250; 3M/ESPE). The control groups (SM and PB) did not receive potassium oxalate application. The prepared teeth were kept in distilled water at 37°C for 24 h and 12 months. They were then cut longitudinally into sticks with a bond area of ∼0.8 mm(2) for submission to the microtensile bond strength test. The data were analyzed by two-factor ANOVA, Tamhane's paired comparisons, and the Student t-test (α = 0.05). The hybrid layer formed was observed by scanning electron microscopy (SEM). SEM analysis of the surfaces treated with PB revealed shorter resin tags associated with the application of potassium oxalate, whereas SM showed tags similar to those without potassium oxalate. A significant difference was shown between the two storage times for each of the protocols. There was a significant difference among SMO, SM, and PBO (24 h), as well as among SM, SMO, and PBO, and between PB and PBO (12 months). The application of potassium oxalate before conventional adhesive systems may result in alteration of the bond strength between dentin and resin composite, depending on the material. Copyright © 2011 Wiley Periodicals, Inc.

Controlled synthesis of porous anhydrous cobalt oxalate nanorods with high reversible capacity and excellent cycling stability

International Nuclear Information System (INIS)

Xu, Junmin; He, Lei; Liu, Hui; Han, Tao; Wang, Yongjian; Zhang, Changjin; Zhang, Yuheng

2015-01-01

Graphical abstract: Display Omitted -- Abstract: One-dimensional porous anhydrous cobalt oxalate nanorods are prepared via a facile water-controlled coprecipitate method followed by thermal annealing treatment under N 2 at 300 °C. The nanorods are characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. When evaluated as an anode material for lithium ion batteries, the nanorods exhibit high reversible specific capacity and excellent cycling stability (924 mA h g −1 at 50 mA g −1 after 100 cycles and 709 mA h g −1 at 200 mA g −1 after 220 cycles). This remarkable electrochemical performance is attributed to the one-dimensional porous nanostructure that can provide large electrode/electrolyte contact area and short lithium-ion diffusion pathway, meanwhile reduce the volume expansion during the repeated discharge/charge process

Effects of reactive Mn(III)-oxalate complexes on structurally intact plant cell walls

Science.gov (United States)

Summering, J. A.; Keiluweit, M.; Goni, M. A.; Nico, P. S.; Kleber, M.

2011-12-01

Lignin components in the in plant litter are commonly assumed to have longer residence times in soil than many other compounds, which are supposedly, more easily degradable. The supposed resistance of lignin compounds to decomposition is generally attributed to the complex chain of biochemical steps required to create footholds in the non-porous structure of ligno-cellulose in cell walls. Interestingly, Mn(III) complexes have shown the ability to degrade ligno-cellulose. Mn(III) chelated by ligands such as oxalate are soluble oxidizers with a high affinity for lignin structures. Here we determined (i) the formation and decay kinetics of the Mn(III)-oxalate complexes in aqueous solution and (ii) the effects that these complexes have on intact ligno-cellulose. UV/vis spectroscopy and iodometric titrations confirmed the transient nature of Mn(III)-oxalate complexes with decay rates being in the order of hours. Zinnia elegans tracheary elements - a model ligno-cellulose substrate - were treated with Mn(III)-oxalate complexes in a newly developed flow-through reactor. Soluble decomposition products released during the treatment were analyzed by GC/MS and the degree of cell integrity was measured by cell counts, pre- and post-treatment counts indicate a decrease in intact Zinnia elegans as a result of Mn(III)-treatment. GC/MS results showed the release of a multitude of solubilized lignin breakdown products from plant cell walls. We conclude that Mn(III)-oxalate complexes have the ability to lyse intact plant cells and solubilize lignin. Lignin decomposition may thus be seen as resource dependent, with Mn(III) a powerful resource that should be abundant in terrestrial characterized by frequent redox fluctuations.

Synthesis, structure and magnetic behavior of a new three-dimensional Manganese phosphite-oxalate: [C2N2H10][Mn2II(OH2)2(HPO3)2(C2O4)

International Nuclear Information System (INIS)

Ramaswamy, Padmini; Mandal, Sukhendu; Natarajan, Srinivasan

2009-01-01

A novel manganese phosphite-oxalate, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been hydothermally synthesized and its structure determined by single-crystal X-ray diffraction. The structure consists of neutral manganese phosphite layers, [Mn(HPO 3 )] ∞ , formed by MnO 6 octahedra and HPO 3 units, cross-linked by the oxalate moieties. The organic cations occupy the middle of the 8-membered one-dimensional channels. Magnetic studies indicate weak antiferromagnetic interactions between the Mn 2+ ions. - Abstract: A new antiferromagnetic three-dimensional inorganic-organic hybrid compound, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been prepared hydrothermally. The compound has neutral manganese layers pillared by oxalate units. The neutral manganese layers are shown here. Display Omitted

Thermodynamic analysis of stability in iron removal from kaolin by using oxalic acid

Directory of Open Access Journals (Sweden)

C. Ocampo-López

2013-06-01

Full Text Available The graphical representation of global stability for a system, or Pourbaix diagram, was constructed to perform a thermodynamic study of iron removal from kaolin using oxalic acid as an oxidant. To do this the free energies of formation of the oxalate complex of the system were calculated, and it was found that the more stable specie is Fe(C2O43-3, with a calculated free energy of formation of -3753.88 kcal/mol. Thermodynamic stability functions were estimated for the system as a function of pH and Eh known as potential of oxide reduction. It was built a global stability diagram for the removal system; it showed that the specie trioxalate Fe(C2O43-3 is the only oxalate in equilibrium with other compounds associated with the removal of iron in kaolin.

In vitro selection of rape variants resistant to oxalic acid using haploid stem apexes

International Nuclear Information System (INIS)

Wang Yifei; Huang Jianhua; Lu Ruiju; Sun Yuefang; Zhou Runmei; Zhou Zhijiang; Xie Zhujie; Liu Chenghong

2002-01-01

Mutagenic treatment was made of the haploid stem apexes rape strain '9841' and '9885' with Pingyangmycin. As a result of positive selection with oxalic acid providing selection pressure, variants with significantly higher tolerance to oxalic acid than the original ones were obtained. 3 germplasm with significantly higher resistance to Sclerotinia sclerotiorum than cultivar Hu You 12 were selected from field test

Deep catalytic oxidative desulfurization (ODS) of dibenzothiophene (DBT) with oxalate-based deep eutectic solvents (DESs).

Science.gov (United States)

Lü, Hongying; Li, Pengcheng; Deng, Changliang; Ren, Wanzhong; Wang, Shunan; Liu, Pan; Zhang, Han

2015-07-07

An oxalate-based DES with a tetrabutyl ammonium chloride and oxalate acid molar ratio of 1/2 (TBO1 : 2) exhibited high activity in oxidative desulfurization (ODS) of dibenzothiophene (DBT) under mild reaction conditions. It is potentially a promising and highly environmentally friendly approach for desulfurization of fuels.

Effect of Surface Precipitate on the Crevice Corrosion in HYBRID and Oxalic Acid Solution

International Nuclear Information System (INIS)

Park, S. Y.; Jung, J. Y.; Won, H. J.; Kim, S. B.; Choi, W. K.; Moon, J. K.; Park, S. J.

2015-01-01

In this study, we investigated the characteristics of the crevice corrosion for Inconel-600 and 304SS in OA solution according to the change in pH. The evaluation of the crevice corrosion with the chemical thermodynamic analysis identified the effect of the residual chemicals such as iron-oxalate and nickeloxalate to the crevice corrosion behavior. Test results were compared with those of HYBRID (HYdrizine Base Reductive metal Ion Decontamination). The crevice corrosion properties of 304 SS and Inconel-600 in HYBRID and oxalic acid solution were evaluated. In case of oxalic acid solution, the corrosion rate on 304SS was rapidly increased with a pH decrease of around 2, but there was no increase in the corrosion rate on Inconel-600

Crystal structure of di?methyl?ammonium hydrogen oxalate hemi(oxalic acid)

OpenAIRE

Diallo, Waly; Gueye, Ndongo; Crochet, Aur?lien; Plasseraud, Laurent; Cattey, H?l?ne

2015-01-01

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-Bu)3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH2)2C2O4 salt and Sn(CH3)3Cl in a 2:1 ratio in ethanol. The asymmetric unit comprises a di?methyl?ammonium cation (Me2NH2 +), an hydrogenoxalate anion (HC2O4 ?), and half a mol?ecule of oxalic acid (H2C2O4) situated about an inversion center. From a supra?molecular point of view, the t...

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

Directory of Open Access Journals (Sweden)

Fan Zhang

2016-10-01

Full Text Available 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, Bax and Caspase3 mRNA also increased while the level of Bcl2 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.

Oxalate Acid-Base Cements as a Means of Carbon Storage

Science.gov (United States)

Erdogan, S. T.

2017-12-01

Emission of CO2 from industrial processes poses a myriad of environmental problems. One such polluter is the portland cement (PC) industry. PC is the main ingredient in concrete which is the ubiquitous binding material for construction works. Its production is responsible for 5-10 % of all anthropogenic CO2 emissions. Half of this emission arises from the calcination of calcareous raw materials and half from kiln fuel burning and cement clinker grinding. There have long been efforts to reduce the carbon footprint of concrete. Among the many ways, one is to bind CO2 to the phases in the cement-water paste, oxides, hydroxides, and silicates of calcium, during early hydration or while in service. The problem is that obtaining calcium oxide cheaply requires the decarbonation of limestone and the uptake of CO2 is slow and limited mainly to the surface of the concrete due to its low gas permeability. Hence, a faster method to bind more CO2 is needed. Acid-base (AB) cements are fast-setting, high-strength systems that have high durability in many environments in which PC concrete is vulnerable. They are made with a powder base such as MgO and an acid or acid salt, like phosphates. Despite certain advantages over PC cement systems, AB cements are not feasible, due to their high acid content. Also, the phosphoric acid used comes from non-renewable sources of phosphate. A potential way to reduce the drawbacks of using phosphates could be to use organic acids. Oxalic acid or its salts could react with the proper powder base to give concrete that could be used for infrastructure hence that would have very high demand. In addition, methods to produce oxalates from CO2, even atmospheric, are becoming widespread and more economical. The base can also be an industrial byproduct to further lower the environmental impact. This study describes the use of oxalic acid and industrial byproducts to obtain mortars with mechanical properties comparable to those of PC mortars. It is

Hydrothermal synthesis and characteristics of 3-D hydrated bismuth oxalate coordination polymers with open-channel structure

International Nuclear Information System (INIS)

Chen Xinxiang; Cao Yanning; Zhang Hanhui; Chen Yiping; Chen Xuehuan; Chai Xiaochuan

2008-01-01

Two new 3-D porous bismuth coordination polymers, (C 5 NH 6 ) 2 [Bi 2 (H 2 O) 2 (C 2 O 4 ) 4 ].2H 2 O 1 and (NH 4 )[Bi(C 2 O 4 ) 2 ].3H 2 O 2, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic symmetry, P2 1 /c space group with a=10.378(2) A, b=17.285(3) A, c=16.563(5) A, α=90 deg., β=119.66(2) deg., γ=90 deg., V=2581.8(10) A 3 , Z=4, R 1 =0.0355 and wR 2 =0.0658 for unique 4713 reflections I >2σ(I). Compound 2 crystallizes in the tetragonal symmetry, I4 1 /amd space group with a=11.7026(17) A, b=11.7026(17) A, c=9.2233(18) A, α=90 deg., β=90 deg., γ=90 deg., V=1263.1(4) A 3 , Z=32, R 1 =0.0208 and wR 2 =0.0518 for unique 359 reflections I> 2σ(I). Compounds 1 and 2 are 3-D open-framework structures with a 6 6 uniform net, which consist of honeycomb-like layers connected to each other by oxalate units. While different guest molecules fill in their cavities of honeycomb-like layers, study of ultrasonic treatment on 2 indicates the replacement of NH 4 + by K + on potassium ion exchange. Thermogravimetric analysis indicates that the open-channel frameworks are thermally stable up to 200 deg. C, and other characterizations are also described by elemental analysis, IR and ultraviolet-visible diffuse reflectionintegral spectrum (UV-Vis DRIS). - Graphical abstract: Two novel 3-D extended porous coordination polymers have been synthesized by hydrothermal method. Both compounds are 3-D open-framework structures with a 6 6 uniform net, which consist of honeycomb-like layers connected to each other by oxalate units. While different guest molecules fill in their cavities of honeycomb-like layers. Study of ultrasonic treatment on 2 indicates the replacement of NH 4 + by K + on potassium ion exchange

Proximally functionalized cavitands and synthesis of a flexible hemicarcerand

NARCIS (Netherlands)

Timmerman, P.; Boerrigter, H.; Verboom, Willem; van Hummel, G.J.; Harkema, Sybolt; Reinhoudt, David

1995-01-01

A general study on the synthesis of partly bridged octols3a-d and4c-d is described. Tri-bridged diol3c can be prepared in 54% yield in DMSO at 70°C with excess CH2BrCl or in 52% yield in DMF at 70°C with only 4 equiv. of CH2BrCl. 1,3-Di-bridged tetrol4a, one of the two possible di-bridged isomers

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

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

International Nuclear Information System (INIS)

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

2006-01-01

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 γ-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 (Γ max ) was ranked the order of IO-250>IO-320>γ-FeOOH>IO-420>IO-520 and the adsorption equilibrium constant (K a ) followed the order of IO-250>IO-520>γ-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 γ-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 ox 0 was ranked as the order of γ-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 3+ and Fe 2+ during the photoreaction were also strongly dependent on the C ox 0 and iron oxides

Determination of alkaloids and oxalates in some selected food ...

African Journals Online (AJOL)

STORAGESEVER

2009-01-05

Jan 5, 2009 ... MATERIALS AND METHODS. Source of samples. Samples ... until the colour of solution changed from salmon pink colour to a faint yellow colour. .... Effect of cooking on the soluble and insoluble oxalate content of some New ...

Laboratory study of the effect of oxalic acid on the cloud condensation nuclei activity of mineral dust aerosol

Science.gov (United States)

Gierlus, Kelly M.; Laskina, Olga; Abernathy, Tricia L.; Grassian, Vicki H.

2012-01-01

Dicarboxylic acids, which make up a significant portion of the atmospheric organic aerosol, are emitted directly through biomass burning as well as produced through the oxidation of volatile organic compounds. Oxalic acid, the most abundant of the dicarboxylic acids, has been shown by recent field studies to be present in mineral dust aerosol particles. The presence of these internally mixed organic compounds can alter the water absorption and cloud condensation nuclei (CCN) abilities of mineral particles in the Earth's atmosphere. The University of Iowa's Multi-Analysis Aerosol Reactor System ( MAARS) was used to measure the CCN activity of internally mixed particles that were generated from a mixture of either calcite or polystyrene latex spheres (PSLs) in an aqueous solution of oxalic acid. Although PSL is not a mineral dust component, it is used here as a non-reactive, insoluble particle. CCN measurements indicate that the internally mixed oxalate/calcite particles showed nearly identical CCN activity compared to the original calcite particles whereas oxalic acid/PSL internally mixed particles showed much greater CCN activity compared to PSL particles alone. This difference is due to the reaction of calcite with oxalic acid, which produces a relatively insoluble calcium oxalate coating on the particle surface and not a soluble coating as it does on the PSL particle. Our results suggest that atmospheric processing of mineral dust aerosol through heterogeneous processes will likely depend on the mineralogy and the specific chemistry involved. Increase in the CCN activity by incorporation of oxalic acid are only expected for unreactive insoluble dust particles that form a soluble coating.

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.

Crystal structure of di­methyl­ammonium hydrogen oxalate hemi(oxalic acid)

Science.gov (United States)

Diallo, Waly; Gueye, Ndongo; Crochet, Aurélien; Plasseraud, Laurent; Cattey, Hélène

2015-01-01

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-Bu)3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH2)2C2O4 salt and Sn(CH3)3Cl 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. PMID:25995858

Nephroprotective effect of Corn Silk extract on oxalic acid-induced nephrocalcinosis in rabbit model

OpenAIRE

Faruk Hassan Al-Jawad; Rafi Abdul Majeed Al-Razzuqi; Zainab Awaen Al-Ebady; Thulfuqar Abdul Majeed Al-Razzuqi

2012-01-01

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...

Physical simulation of precipitation of radioactive element oxalates by using the harmless neodymium oxalate for studying the agglomeration phenomena

International Nuclear Information System (INIS)

Lalleman, Sophie; Bertrand, Murielle; Plasari, Edouard

2012-01-01

Oxalic precipitation is usually applied in nuclear industry to process radioactive wastes or to recover actinides from a multicomponent solution.This paper deals with the development of methods adapted to a nuclear environment in order to study the agglomeration phenomena during actinide oxalic precipitation.These methods are previously set up with harmless elements that simulate the actinide behaviour: the lanthanides. A parametric study is carried out to quantify the influence of operating parameters on the agglomeration kernel and to determine a kinetic law for this mechanism. The experimental study is performed in a continuous-MSMPR precipitator at steady-state. The method is based on the resolution of two population balances using the moment approach, one for elementary crystals and the other for agglomerates. Provided that the kinetic rates of nucleation and growth are known, the agglomeration kernel can be obtained from a mathematical treatment of the experimental particle size distributions. Results point out that experimental crystal sizes are consistent with an independent kernel. It appears that the agglomeration kernel is directly proportional to supersaturation, increases with temperature but is limited by ionic strength and shear rate. (authors)

A novel 3D framework indium phosphite-oxalate based on a pcu-type topology

International Nuclear Information System (INIS)

Zuo, Mengmeng; Zhou, Mingdong; Hu, Dianwen; Gao, Fan; Dong, Sijie; Huang, Liangliang

2016-01-01

A new inorganic–organic hybrid indium phosphite-oxalate, formulated as H[In 5 (HPO 3 ) 6 (H 2 PO 3 ) 2 (C 2 O 4 ) 2 ]·(C 4 N 2 H 11 ) 2 ·H 2 O 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), [C 2 O 4 ] 2− groups and [H 2 PO 3 ] − 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. - Graphical abstract: A 3D open-framework indium phosphite-oxalate has been synthesized under hydrothermal conditions. A classical SBU, D6R, is present in the structure. By regarding D6R as the 6-connected nodes, the inorganic–organic hybrid framework is based on a pcu-type topology. - Highlights: • A new indium phosphite-oxalate based on a pcu-type topology has been synthesized. • A classical SBU, D6R, is present in the structure. • The classical SBU is firstly reported in main metal phosphite/phosphite-oxalate.

Impedance and hydrogen evolution studies on magnesium alloy in oxalic acid solution containing different anions

Energy Technology Data Exchange (ETDEWEB)

Fekry, A.M. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

2010-12-15

The corrosion behavior of AZ31E alloy was investigated in oxalic acid solution using different electrochemical techniques. The effect of concentration was studied, where the corrosion rate was found to increase with increasing oxalic acid concentration and hydrogen evolution. The effect of adding Cl{sup -}, F{sup -} or PO{sub 4}{sup 3-} ions on the electrochemical behavior of AZ31E electrode was studied in 0.01 M oxalic acid solution at 298 K. It was found that the corrosion rate increases with increasing Cl{sup -} or F{sup -} ion concentration, however, it decreases with increasing PO{sub 4}{sup 3-} ion concentration. Good agreement was observed between the results obtained from electrochemical techniques and confirmed by Scanning electron micrographs. (author)

Trace element studies in urolithiasis; preliminary investigation on mixed calcium oxalate-struvite urinary calculi

International Nuclear Information System (INIS)

Syed, A.M.; Qadiruddin, M.; Shirin, K.; Manser, W.W.T.

1999-01-01

In this study the levels of the trace elements copper , zinc, lead, iron, aluminum, nickel, chromium along with magnesium, sodium and potassium were estimated in fifteen mixed calcium oxalate-struvite (CaOx/STR) urinary stones. The mean values of the combined results were, copper 4.24, zinc 1302, zinc 1302.10, lead 23.25, iron 36.83,nickel 0.69, chromium 1.93, magnesium 4530441, sodium 54.13 and potassium 5.93 ng mg/sup -1/. It was observed that zinc, aluminum and potassium levels were higher than in calcium oxalate(CaOx) calculi 0.05>P>0.02 and potassium levels were higher than in mixed calcium oxalate-hydroxy appetite (CaOx/APA) calculi, P<0.01. A combination of all the results was also compared with similar data from South Africa, Turkey, Austria, India, U.S.A and Japan. (author)

Salubrious effect of C-phycocyanin against oxalate-mediated renal cell injury.

Science.gov (United States)

Farooq, Shukkur Muhammed; Asokan, Devarajan; Sakthivel, Ramasamy; Kalaiselvi, Periandavan; Varalakshmi, Palaninathan

2004-10-01

C-phycocyanin, a biliprotein pigment found in some blue green algae (Spirulina platensis) with nutritional and medicinal properties, was investigated for its efficacy on sodium oxalate-induced nephrotoxicity in experimentally induced urolithic rats. Male Wistar rats were divided into four groups. Hyperoxaluria was induced in two of these groups by intraperitoneal infusion of sodium oxalate (70 mg/kg), and a pretreatment of phycocyanin (100 mg/kg) as a single oral dosage was given to one of these groups by 1 h prior to sodium oxalate infusion challenges. The study also encompasses an untreated control group and a phycocyanin-alone treated drug control group. The extent of lipid peroxidation (LPO) was evaluated in terms of renal concentrations of MDA, conjugated diene and hydroperoxides. The following assay was performed in the renal tissue (a) antioxidant enzymes such as superoxide dismutase (SOD) and catalase, (b) glutathione metabolizing enzymes such as glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST) and glucose 6-phosphate dehydrogenase (G6PD), (c) the low molecular weight antioxidants (GSH, vitamins E and C) and protein carbonyl content. The increased concentrations of MDA, conjugated diene and hydroperoxide (index of the lipid peroxidation) were controlled (P antioxidants were appreciably increased (P antioxidants. It was noticed that the activities of antioxidant enzymes and glutathione metabolizing enzymes were considerably stabilized in rats pretreated with phycocyanin. We suggest that phycocyanin protects the integrity of the renal cell by stabilizing the free radical mediated LPO and protein carbonyl, as well as low molecular weight antioxidants and antioxidant enzymes in renal cells. Thus, the present analysis reveals that the antioxidant nature of C-phycocyanin protects the renal cell against oxalate-induced injury and may be a nephroprotective agent.

Highly Water-Stable Lanthanide-Oxalate MOFs with Remarkable Proton Conductivity and Tunable Luminescence.

Science.gov (United States)

Zhang, Kun; Xie, Xiaoji; Li, Hongyu; Gao, Jiaxin; Nie, Li; Pan, Yue; Xie, Juan; Tian, Dan; Liu, Wenlong; Fan, Quli; Su, Haiquan; Huang, Ling; Huang, Wei

2017-09-01

Although proton conductors derived from metal-organic frameworks (MOFs) are highly anticipated for various applications including solid-state electrolytes, H 2 sensors, and ammonia synthesis, they are facing serious challenges such as poor water stability, fastidious working conditions, and low proton conductivity. Herein, we report two lanthanide-oxalate MOFs that are highly water stable, with so far the highest room-temperature proton conductivity (3.42 × 10 -3 S cm -1 ) under 100% relative humidity (RH) among lanthanide-based MOFs and, most importantly, luminescent. Moreover, the simultaneous response of both the proton conductivity and luminescence intensity to RH allows the linkage of proton conductivity with luminescence intensity. This way, the electric signal of proton conductivity variation versus RH will be readily translated to optical signal of luminescence intensity, which can be directly visualized by the naked eye. If proper lanthanide ions or even transition-metal ions are used, the working wavelengths of luminescence emissions can be further extended from visible to near infrared light for even wider-range applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

The effect of processing and preservation methods on the oxalate ...

African Journals Online (AJOL)

Dr. J. T. Ekanem

vegetables and consequently the associated food safety problems. Keywords: .... vegetables prepared in slightly two different ... Table 2: Oxalate levels of selected leafy vegetables as a function of cooking method and the interplay of freezing.

Recovery of plutonium from nitric acid containing oxalate and fluoride by a macroporous bifunctional phosphinic acid resin (MPBPA)

International Nuclear Information System (INIS)

Venugopal Chetty, K.; Godbole, A.G.; Swarup, R.; Vaidya, V.N.; Venugopal, V.; Vasudeva Rao, P.R.

2006-01-01

The sorption of Pu from nitric acid solutions containing oxalate/fluoride was studied using an indigenously available macroporous bifunctional phosphinic acid (MPBPA) resin. Batch experiments were carried out to obtain the distribution data of Pu(IV) with a view to optimize conditions for its recovery from nitric acid waste solutions containing oxalate or fluoride ions. The measurements showed high distribution ratio (D) values even in the presence of strong complexing ions, like oxalate and fluoride, indicating the possibility of recovery of Pu from these types of waste solution. Column studies were carried out using this resin to recover Pu from the oxalate supernatant waste solution, which showed that up to 99% of Pu could be adsorbed on the resin. Elution of Pu loaded on the resin was studied using different eluting agents. (author)

Synthesis and characterization of polymorphs of photoluminescent Eu(III)-(2,5-furandicarboxylic acid, oxalic acid) MOFs

Science.gov (United States)

Shi, Fa-Nian; Ananias, Duarte; Yang, Ting-Hai; Rocha, João

2013-08-01

A novel metal organic framework (MOF) formulated as [Eu(H2O)2(fdc)(ox)0.5·(H2O)]n (1, fdc2-=2,5-furandicarboxylate, ox2-=oxalate), was hydrothermally synthesized via in situ ox2- generation from the partial decomposition of the fdc2- ligand. This material crystallizes in the monoclinic space group C2/c, unit cell parameters of 1: a=16.7570(10), b=10.5708(7), c=13.5348(14) Å, β=116.917(2)° (Z=8), and exhibits a three-dimensional (3D)-porous framework, with guest water molecules residing in the channel linking all other ligands (H2O, ox2-and fdc2-) via hydrogen bonding interactions. Compound 2 is a polymorph of 1 crystallizing in monoclinic P21/c space group. The photoluminescence properties of 1 and 2 were studied at room temperature. The spectra show the typical Eu3+ red emission and the differences observed reflects the slightly different structures of these polymorphs.

The role of nanoparticulate agglomerates in TiO{sub 2} photocatalysis: degradation of oxalic acid

Energy Technology Data Exchange (ETDEWEB)

Ivanova, Irina [Leibniz Universitaet Hannover, Institut fuer Technische Chemie (Germany); Mendive, Cecilia B., E-mail: cbmendive@mdp.edu.ar [Universidad Nacional de Mar del Plata, Facultad de Ciencias Exactas y Naturales, Departamento de Química (Argentina); Bahnemann, Detlef [Leibniz Universitaet Hannover, Institut fuer Technische Chemie (Germany)

2016-07-15

The simultaneous bimodal study of the photocatalytic oxalic acid degradation by aqueous TiO{sub 2} 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 TiO{sub 2} agglomerates in which these molecules are hidden from the effect of the light, thus being protected from photocatalytic degradation. Studies of different TiO{sub 2} 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.Graphical AbstractFig.: Deaggregation of TiO{sub 2} particle agglomerates upon UV illumination.

Coordination of manganous ion at the active site of pyruvate, phosphate dikinase: the complex of oxalate with the phosphorylated enzyme

International Nuclear Information System (INIS)

Kofron, J.L.; Ash, D.E.; Reed, G.H.

1988-01-01

Electron paramagnetic resonance spectroscopy has been used to investigate the structure of the complex of manganous ion with the phosphorylated form of pyruvate, phosphate dikinase (E/sub p/) and the inhibitor oxalate. Oxalate, an analogue of the enolate of pyruvate, is competitive with respect to pyruvate in binding to the phosphorylated form of the enzyme. Superhyperfine coupling between the unpaired electrons of Mn(I) and ligands specifically labeled with 17 O has been used to identify oxygen ligands to Mn(II) in the complex with oxalate and the phosphorylated form of the enzyme. Oxalate binds at the active site as a bidentate chelate with Mn(II). An oxygen from the 3'-N-phosphohistidyl residue of the protein is in the coordination sphere of Mn(II), and at least two water molecules are also bound to Mn(II) in the complex. Oxalate also binds directly to Mn(II) in a complex with nonphosphorylated enzyme. The structure for the E/sub p/-Mn(II)-oxalate complex implies that simultaneous coordination of a phospho group and of the attacking nucleophile to the divalent cation is likely an important factor in catalysis of this phospho-transfer reaction

Oxalate molecule as the trap for gamma-irradiation energy in the amorphous aluminosilicate Al2(OH)6H4SiO4

International Nuclear Information System (INIS)

Nothig-Laslo, V.; Horvath, L.; Bilinski, H.

1990-01-01

Paramagnetic species which were the products of gamma irradiation at 77 K and at room temperature were studied by ESR spectroscopy in the amorphous aluminosilicate, Al2(OH)6H4SiO4, prepared in the presence and in the absence of oxalate ion. The aluminosilicate precipitated from the solution containing the oxalate ion in 10(-4) mol dm-3 concentration contained the oxalate only in trace amounts. When gamma-irradiated at 77 K and at room temperature, this compound gave the stable paramagnetic species represented by the single ESR line centered at g = 2.000. We ascribe this spectrum to the CO2- radical formed from the oxalate ion. The same aluminosilicate prepared in the absence of the oxalate either produced no stable paramagnetic product after gamma irradiation at room temperature or resulted in composite ESR spectra, indicating the presence of several paramagnetic species if irradiated at 77 K. Complex ESR spectra were transformed by heating to the stable paramagnetic centers which differed from the one obtained from oxalate ion. We conclude that in Al2(OH)6H4SiO4 oxalate acts as a trap for the gamma-radiation energy

Adsorption and oxidation of oxalic acid on anatase TiO2 (001) surface: A density functional theory study.

Science.gov (United States)

Sun, Tao; Wang, Yun; Zhang, Haimin; Liu, Porun; Zhao, Huijun

2015-09-15

Anatase TiO2 (001) surfaces have attracted great interest for photo-degradation of organic species recently due to their high reactivity. In this work, adsorption properties and oxidation mechanisms of oxalic acid on the anatase TiO2 (001) surface have been theoretically investigated using the first-principles density functional theory. Various possible adsorption configurations are considered by diversifying the connectivity of carboxylic groups with the surface. It is found that the adsorption of oxalic acid on the anatase (001) surface prefer the dissociative states. A novel double-bidentate configuration has been found due to the structural match between oxalic acid and the (001) surface. More charge is transferred from the adsorbed oxalic acid to the surface with the double-bidentate configuration when comparing with other adsorption structures. Thus, there is a positive correlation relationship between the transferred charge amount and the interfacial bond numbers when oxalic acid adsorbs on the anatase TiO2 (001) surface. The adsorption energies with dispersion corrections have demonstrated that the van der Waals interactions play an important role in the adsorption, especially when adsorbates are close to the surface. Copyright © 2015 Elsevier Inc. All rights reserved.

Oxalate contributes to the resistance of Gaillardia grandiflora and Lupinus sericeus to a phytotoxin produced by Centaurea maculosa.

Science.gov (United States)

Weir, Tiffany L; Bais, Harsh Pal; Stull, Valerie J; Callaway, Ragan M; Thelen, Giles C; Ridenour, Wendy M; Bhamidi, Suresh; Stermitz, Frank R; Vivanco, Jorge M

2006-03-01

Centaurea maculosa Lam. is a noxious weed in western North America that produces a phytotoxin, (+/-)-catechin, which is thought to contribute to its invasiveness. Areas invaded by C. maculosa often result in monocultures of the weed, however; in some areas, North American natives stand their ground against C. maculosa and show varying degrees of resistance to its phytotoxin. Two of these resistant native species, Lupinus sericeus Pursh and Gaillardia grandiflora Van Houtte, were found to secrete increased amounts of oxalate in response to catechin exposure. Mechanistically, we found that oxalate works exogenously by blocking generation of reactive oxygen species in susceptible plants and reducing oxidative damage generated in response to catechin. Furthermore, field experiments show that L. sericeus indirectly facilitates native grasses in grasslands invaded by C. maculosa, and this facilitation can be correlated with the presence of oxalate in soil. Addition of exogenous oxalate to native grasses and Arabidopsis thaliana (L.) Heynh grown in vitro alleviated the phytotoxic effects of catechin, supporting the field experiments and suggesting that root-secreted oxalate may also act as a chemical facilitator for plant species that do not secrete the compound.

Recovery of plutonium from oxalate bearing solutions using a mixture of CMPO and TBP

International Nuclear Information System (INIS)

Mathur, J.N.; Murali, M.S.; Rizvi, G.H.; Iyer, R.H.; Badheka, L.P.; Banerji, A.; Michael, K.M.; Kapoor, S.C.; Dhumwad, R.K.

1993-01-01

A simple and efficient procedure has been developed to quantitatively recover Pu from oxalate bearing solutions using a mixture of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and TBP in dodecane. Pu(IV) in the range of 6.9 to 34.6 mg/1 was quantitatively extracted into 0.2 M CMPO+ 1.2 M TBP in dodecane from an aqueous solution containing 3.0 M HNO 3 and 0.1 M H 2 C 2 O 4 . At such low concentrations of Pu, the distribution ratio (D) did not change but the increase in oxalic acid concentration drastically reduced these values. The variation in HNO 3 concentration at a fixed concentration of 0.2 M CMPO + 1.2 M TBP has shown a dramatic increase in the D values, being 0.3 at 1.0 M and > 10 4 at 7.5 M. The extraction was almost quantitative even at the aqueous to organic ratio of 10:1. Plutonium could be quantitatively recovered (i) by stripping with 0.5 M acetic acid and (ii) by coprecipitating it directly from the organic phase with 0.3 M oxalic acid + 0.3 M calcium nitrate + sodium nitrite. ∼ 92% of the Pu was found in the precipitate and ∼7% in the supernatant. Using this procedure Pu, in a concentrated form (∼50 times), could be recovered from the oxalate bearing solutions without recourse to the destruction of oxalate ion. The slope of 2 from the nitrate ion as well as CMPO variation experiments suggest the species in the organic phase to be PuC 2 O 4 (NO 3 ) 2 .2CMPO. The absorption spectral study of Pu(IV) confirmed the above species in the organic phase. (author). 19 refs., 5 figs., 9 tabs

In vitro anti-inflammatory activity of selected oxalate-degrading probiotic bacteria: potential applications in the prevention and treatment of hyperoxaluria.

Science.gov (United States)

Giardina, Silvana; Scilironi, Cristina; Michelotti, Angela; Samuele, Alberta; Borella, Fabio; Daglia, Maria; Marzatico, Fulvio

2014-03-01

Oxalate (Ox) is a very common component of the human diet, capable to collect in the renal tissue and bind calcium to form calcium oxalate (CaOx) crystals. A supersaturation of CaOx crystal may cause nephrocalcinosis and nephrolithiasis. The inflammation derived from the CaOx crystal accumulation, together with innate or secondary renal alterations, could strongly affect the renal function. In this case a consumption of probiotics with either oxalate-degrading activity at intestinal level and systemic anti-inflammatory activity could be an alternative approach to treat the subjects with excess of urinary oxalate excretion. 11 strains of lactic acid bacteria (Lactobacilli and Bifidobacteria), already included in the list of bacteria safe for the human use, were investigated for their capability to degrade oxalate by mean of RP-HPLC-UV method and modulate inflammation in an in vitro model system based on peripheral blood mononuclear cells. Four promising bacterial strains (Lactobacillus plantarum PBS067, Lactobacillus acidophilus LA-14, Bifidobacterium breve PBS077, Bifidobacterium longum PBS078) were identified as innovative biological tools for the prevention and the therapeutic treatment of hyperoxaluria and the inflammatory events associated to the Ox accumulation. The oxalate-degrading activity of some probiotics and their capability to modulate the release of inflammation mediators could be exploited as a new nutraceutical and therapeutic approach for the treatment of oxalate accumulation and the related inflammatory state. © 2014 Institute of Food Technologists®

Porous aluminum room temperature anodizing process in a fluorinated-oxalic acid solution

Science.gov (United States)

Dhahri, S.; Fazio, E.; Barreca, F.; Neri, F.; Ezzaouia, H.

2016-08-01

Anodizing of aluminum is used for producing porous insulating films suitable for different applications in electronics and microelectronics. Porous-type aluminum films are most simply realized by galvanostatic anodizing in aqueous acidic solutions. The improvement in application of anodizing technique is associated with a substantial reduction of the anodizing voltage at appropriate current densities as well as to the possibility to carry out the synthesis process at room temperature in order to obtain a self-planarizing dielectric material incorporated in array of super-narrow metal lines. In this work, the anodizing of aluminum to obtain porous oxide was carried out, at room temperature, on three different substrates (glass, stainless steel and aluminum), using an oxalic acid-based electrolyte with the addition of a relatively low amount of 0.4 % of HF. Different surface morphologies, from nearly spherical to larger porous nanostructures with smooth edges, were observed by means of scanning electron microscopy. These evidences are explained by considering the formation, transport and adsorption of the fluorine species which react with the Al3+ ions. The behavior is also influenced by the nature of the original substrate.

Sinteractive thoria powders derived through gel-combustion and oxalate deagglomeration - a comparison

International Nuclear Information System (INIS)

Ananthasivan, K.; Balakrishnan, S.; Anthonysamy, S.; Ganesan, V.; Vasudeva Rao, P.R.

2011-01-01

Thorium dioxide finds extensive application in the nuclear industry. Pellets of thoria are used in PHWRs for flux flattening and in FBRs as a blanket material. The development of advanced methods for the synthesis and sintering of thoria is relevant to these applications. This paper attempts to compare the properties of sinteractive nanocrystalline thoria (pure and doped with Ca 2+ and Mg 2+ ) synthesized in our laboratory through two different techniques, viz. gel-combustion and oxalate de-agglomeration. In all the investigations cited above the precursors obtained by using both the procedures were calcined in air at 1073 K. The thoria powders thus obtained were characterised for their specific surface area (SSA), X-ray crystallite size (XCS), bulk density, particle size distribution and residual carbon content. These powders were pelletised and sintered at 1473, 1673, and 1873 K. The sinterability of these powders was compared by measuring the density of the sintered pellets. A matrix density as high as 96.8 % TD (gel combustion) or 98.6 % TD (de-agglomeration) could be obtained at 1873 K, with the powders doped with 0.5 mole % calcia. (author)

An Assessment of Engineered Calcium Oxalate Crystal Formation on Plant Growth and Development as a Step toward Evaluating Its Use to Enhance Plant Defense.

Directory of Open Access Journals (Sweden)

Paul A Nakata

Full Text Available 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.

Acute kidney injury associated with ingestion of star fruit: Acute oxalate nephropathy.

Science.gov (United States)

Barman, A K; Goel, R; Sharma, M; Mahanta, P J

2016-01-01

Starfruit ( Averrhoa carambola ) and its juice are popular in the Indian subcontinent as an indigenous medicine. Oxalate concentration in this fruit and it's freshly prepared juice is very high. We present a report of patients presenting with acute kidney injury due to oxalate nephropathy admitted in a single center. All patients had history of ingesting star fruit. Patients became symptomatic after 10-12 h of eating and main symptoms were pain abdomen and decrease in urine output. Three patients needed hemodialysis. All improved with complete renal recovery. Taking star fruit in large amount on an empty stomach and in a dehydrated state is a risk factor for nephrotoxicity.

Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions in nitric and perchloric acid solutions

International Nuclear Information System (INIS)

Nikitenko, S.I.; Astafurova, L.N.

1991-01-01

Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions are studied spectrometrically. It is shown that even at small oxalate concentrations a notable effect of tetravalent uranium stabilization is observed relatively to the oxidation with nitrous acid. In case of a significant excess of oxalate-ions the oxidation rate will be considerably slower as a result of the formation of U(4) bisoxalate complex

Assembly of an Oxalate Decarboxylase Produced under σK Control into the Bacillus subtilis Spore Coat

Science.gov (United States)

Costa, Teresa; Steil, Leif; Martins, Lígia O.; Völker, Uwe; Henriques, Adriano O.

2004-01-01

Over 30 polypeptides are synthesized at various times during sporulation in Bacillus subtilis, and they are assembled at the surface of the developing spore to form a multilayer protein structure called the coat. The coat consists of three main layers, an amorphous undercoat close to the underlying spore cortex peptidoglycan, a lamellar inner layer, and an electron-dense striated outer layer. The product of the B. subtilis oxdD gene was previously shown to have oxalate decarboxylase activity when it was produced in Escherichia coli and to be a spore constituent. In this study, we found that OxdD specifically associates with the spore coat structure, and in this paper we describe regulation of its synthesis and assembly. We found that transcription of oxdD is induced during sporulation as a monocistronic unit under the control of σK and is negatively regulated by GerE. We also found that localization of a functional OxdD-green fluorescent protein (GFP) at the surface of the developing spore depends on the SafA morphogenetic protein, which localizes at the interface between the spore cortex and coat layers. OxdD-GFP localizes around the developing spore in a cotE mutant, which does not assemble the spore outer coat layer, but it does not persist in spores produced by the mutant. Together, the data suggest that OxdD-GFP is targeted to the interior layers of the coat. Additionally, we found that expression of a multicopy allele of oxdD resulted in production of spores with increased levels of OxdD that were able to degrade oxalate but were sensitive to lysozyme. PMID:14973022

Crystal structure of a mixed-ligand terbium(III coordination polymer containing oxalate and formate ligands, having a three-dimensional fcu topology

Directory of Open Access Journals (Sweden)

Chainok Kittipong

2016-01-01

Full Text Available The title compound, poly[(μ3-formato(μ4-oxalatoterbium(III], [Tb(CHO2(C2O4]n, is a three-dimensional coordination polymer, and is isotypic with the LaIII, CeIII and SmIII analogues. The asymmetric unit contains one TbIII ion, one formate anion (CHO2− and half of an oxalate anion (C2O42−, the latter being completed by application of inversion symmetry. The TbIII ion is nine-coordinated in a distorted tricapped trigonal–prismatic manner by two chelating carboxylate groups from two C2O42− ligands, two carboxylate oxygen atoms from another two C2O42− ligands and three oxygen atoms from three CHO2− ligands, with the Tb—O bond lengths and the O—Tb—O bond angles ranging from 2.4165 (19 to 2.478 (3 Å and 64.53 (6 to 144.49 (4°, respectively. The CHO2− and C2O42− anions adopt μ3-bridging and μ4-chelating-bridging coordination modes, respectively, linking adjacent TbIII ions into a three-dimensional 12-connected fcu topology with point symbol (324.436.56. The title compound exhibits thermal stability up to 623 K, and also displays strong green photoluminescence in the solid state at room temperature.

'Chocolate' silver nanoparticles: Synthesis, antibacterial activity and cytotoxicity.

Science.gov (United States)

Chowdhury, Neelika Roy; MacGregor-Ramiasa, Melanie; Zilm, Peter; Majewski, Peter; Vasilev, Krasimir

2016-11-15

Silver nanoparticles (AgNPs) have emerged as a powerful weapon against antibiotic resistant microorganisms. However, most conventional AgNPs syntheses require the use of hazardous chemicals and generate toxic organic waste. Hence, in recent year's, plant derived and biomolecule based synthetics have has gained much attention. Cacao has been used for years for its medicinal benefits and contains a powerful reducing agent - oxalic acid. We hypothesized that, due to the presence of oxalic acid, cacao extract is capable of reducing silver nitrate (AgNO3) to produce AgNPs. In this study, AgNPs were synthesized by using natural cacao extract as a reducing and stabilizing agent. The reaction temperature, time and reactant molarity were varied to optimize the synthesis yield. UV-visible spectroscopy (UV-vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM) characterization demonstrated that the synthesized AgNPs were spherical particles ranging in size from 35 to 42.5nm. The synthesized AgNPs showed significant antibacterial activity against clinically relevant pathogens such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. Importantly, these green AgNPs are not cytotoxic to human dermal fibroblasts (HDFs) at concentrations below 32μg/ml. We conclude that cacao-based synthesis is a reproducible and sustainable method for the generation of stable antimicrobial silver nanoparticles with low cytotoxicity to human cells. The AgNPs synthesized in this work have promising properties for applications in the biomedical field. Copyright © 2016 Elsevier Inc. All rights reserved.

Optimization of the conditions for the precipitation of thorium oxalate. II. Minimization of the product losses

International Nuclear Information System (INIS)

Pazukhin, E.M.; Smirnova, E.A.; Krivokhatskii, A.S.; Pazukhina, Yu.L.; Kiselev, P.P.

1987-01-01

The precipitation of thorium as a poorly soluble oxalate was investigated. An equation relating the concentrations of the metal and nitric acid in the initial solution and the amount of precipitant required to minimize the product losses was derived. A graphical solution of the equation is presented for the case where the precipitant is oxalic acid at a concentration of 0.78 M

The influence of freezer storage of urine samples on the BONN-Risk-Index for calcium oxalate crystallization.

Science.gov (United States)

Laube, Norbert; Zimmermann, Diana J

2004-01-01

This study was performed to quantify the effect of a 1-week freezer storage of urine on its calcium oxalate crystallization risk. Calcium oxalate is the most common urinary stone material observed in urolithiasis patients in western and affluent countries. The BONN-Risk-Index of calcium oxalate crystallization risk in human urine is determined from a crystallization experiment performed on untreated native urine samples. We tested the influence of a 1-week freezing on the BONN-Risk-Index value as well as the effect of the sample freezing on the urinary osmolality. In vitro crystallization experiments in 49 native urine samples from stone-forming and non-stone forming individuals were performed in order to determine their calcium oxalate crystallization risk according to the BONN-Risk-Index approach. Comparison of the results derived from original sample investigations with those obtained from the thawed aliquots by statistical evaluation shows that i) no significant deviation from linearity between both results exists and ii) both results are identical by statistical means. This is valid for both, the BONN-Risk-Index and the osmolality data. The differences in the BONN-Risk-Index results of both procedures of BONN-Risk-Index determination, however, exceed the clinically acceptable difference. Thus, determination of the urinary calcium oxalate crystallization risk from thawed urine samples cannot be recommended.

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.

Preparation and characterization of alumina supported nickel-oxalate catalyst for the hydrodeoxygenation of oleic acid into normal and iso-octadecane biofuel

International Nuclear Information System (INIS)

Ayodele, O.B.; Togunwa, Olayinka S.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

2014-01-01

Highlights: • Preparation of nickel oxalate complex as catalyst precursor. • Incorporation of nickel oxalate complex into alumina support. • Characterization of the alumina supported nickel oxalate catalyst. • Hydrodeoxygenation of oleic acid with nickel oxalate catalyst. • Nickel oxalate catalyst reusability studies. - Abstract: In this study, nickel II oxalate complex (NiOx) was prepared by functionalization of nickel with oxalic acid (OxA) and incorporated into Al 2 O 3 to synthesize alumina supported nickel oxalate (NiOx/Al 2 O 3 ) catalyst for the hydrodeoxygenation (HDO) of oleic acid (OA) into biofuel. The synthesized NiOx/Al 2 O 3 was characterized and the X-ray fluorescence and elemental dispersive X-ray results showed that NiOx was successfully incorporated into the structure of Al 2 O 3 . The X-ray diffraction and Raman spectroscopy results confirmed that highly dispersed Ni species are present in the NiOx/Al 2 O 3 due to the functionalization with OxA. The catalytic activity of the NiOx/Al 2 O 3 on the HDO of OA produced a mixture of 21% iso-C18 and 72% n-C18 at a 360 °C, 20 bar, 30 mg NiOx/Al 2 O 3 loading pressure and gas flow rate of 100 mL/min. The presence of i-C 18 was ascribed to the OxA functionalization which increased the acidity of NiOx/Al 2 O 3 . The NiOx/Al 2 O 3 reusability study showed consistent HDO ability after 5 runs. These results are promising for further research into biofuel production for commercialization

[Clinical, laboratory, and functional characteristic of patients with bronchial asthma and chronic obstructive pulmonary disease with disturbances of oxalic acid metabolism].

Science.gov (United States)

Shaĭlieva, L O; Fedoseev, G B; Zorina, M L; Petrova, M A; Trofimov, V I; Kakliugin, A P

2013-01-01

We studied the role of oxalate release through the airways as a potential injurious factor in the development of inflammation, bronchial obstruction and cough syndrome (respiratory oxalosis). Detection of oxalates in bronhcoalveolar lavage fluid and daily urine is the most valuable method for diagnostics of oxalates. Systemic effects, such as cholelithiasis, urolithiasis, and spinal osteochondrosis are characteristic clinical signs of respiratory oxalosis, besides purely respiratory symptoms.

Luminescent and morphological study of Sr2CeO4 blue phosphor prepared from oxalate precursors

International Nuclear Information System (INIS)

Ferrari, Jefferson L.; Pires, Ana M.; Serra, Osvaldo A.; Davolos, Marian R.

2011-01-01

Luminescent and morphological studies of Sr 2 CeO 4 blue phosphor prepared from cerium-doped strontium oxalate precursor are reported. Powder samples were prepared from 5 and 25 mol% Ce 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 2 CeO 4 material are little affected by the SrCO 3 remaining from precursors. The Sr 2 CeO 4 material consists in one-dimensional chains of edge-sharing CeO 6 octahedra that are linked together by Sr 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 2- and Ce 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 μm.

Competitive adsorption and photodegradation of salicylate and oxalate on goethite

Czech Academy of Sciences Publication Activity Database

Krýsa, J.; Jirkovský, Jaromír; Bajt, O.; Mailhot, G.

2011-01-01

Roč. 161, č. 1 (2011), s. 221-227 ISSN 0920-5861 R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : goethite * oxalate * salicylate Subject RIV: CG - Electrochemistry Impact factor: 3.407, year: 2011

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

Catalytic ozonation of oxalate with a cerium supported palladium oxide: An efficient degradation not relying on hydroxyl radical oxidation

KAUST Repository

Zhang, Tao; Li, Weiwei; Croue, Jean-Philippe

2011-01-01

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.

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.

Precipitation behavior of uranium in multicomponent solution by oxalic acid

International Nuclear Information System (INIS)

Shin, Y.J.; Kim, I.S.; Lee, W.K.; Shin, H.S.; Ro, S.G.

1996-01-01

A study on the precipitation of uranium by oxalic acid was carried out in a multicomponent solution. The precipitation method is usually applied to the treatment of radioactive waste and the recovery of uranium from a uranium-scrap contaminated with impurities. In these cases, the problem is how to increase the precipitation yield of target element and to prevent impurities from coprecipitation. The multicomponent solution in the present experiment was prepared by dissolving U, Nd, Cs and Sr in nitric acid. The effects of concentrations of oxalic acid and ascorbic acid on the precipitation yield and purity of uranium were observed. As results of the study, the maximum precipitation yield of uranium is revealed to be about 96.5% and the relative precipitation ratio of Nd, Cs and Sr versus uranium are discussed at the condition of the maximum precipitation yield of uranium, respectively. (author). 11 refs., 5 figs., 1 tab

Structural features and electrochemical properties of nanostructured ZnCo2O4 synthesized by an oxalate precursor method

International Nuclear Information System (INIS)

Kang, Wenpei; Feng, Fan; Zhang, Miaomiao; Liu, Shaojie; Shen, Qiang

2013-01-01

As a Li-ion battery anode, the active substance with a porous nanostructure can be endowed with a high electrochemical performance because of its porosity and remarkable surface area. In this paper, the thermal decomposition of zinc–cobalt binary oxalate precursors, precipitated from a solvothermal medium of ethanol and water (75/25, v/v) at 100 °C, has been performed to synthesize phase-pure ZnCo 2 O 4 spinels, thoroughly giving porous and rod-like configurations with an average length of a few micrometers. Interestingly, each of the as-obtained porous microrods has been well characterized to consist of ∼35.2-nm single-crystalline nanoparticles with polydisperse interspaces. More interestingly, porous ZnCo 2 O 4 microrods can deliver an initial specific discharge capacity of 1,293.7 mAh g −1 with the coulombic efficiency of 76.8 % at 0.2 A g −1 , reaching a value of 937.3 mAh g −1 over 100 discharge–charge cycles. Even at a high current density of 2.0 A g −1 , the porous ZnCo 2 O 4 nanostructures can still possess a reversible discharge capacity of ∼925.0 mAh g −1 , further assigned to the synergistic effect of Zn- and Co-based oxide components. Anyway, the facile oxalate precursor method can realize the controlling synthesis of porous and rod-like ZnCo 2 O 4 nanostructures with a high electrochemical performance

Quantitative Mineralogical Composition of Calculi and Urine Abnormalities for Calcium Oxalate Stone Formers: A Single-Center Results.

Science.gov (United States)

Kustov, Andrey V; Strelnikov, Alexander I

2017-12-26

The paper focuses on the relationship of risk factors and metabolic disorders with mineralogical composition of calculi, age and gender of calcium oxalate stone formers. Stone mineralogical composition, 24 hour biochemistry and pH-profile of urine were examined for sixty four stone formers using powder X-ray diffraction, spectrophotometric and potentiometric techniques. The analysis indicated that 44 % of calculi were composed of pure calcium oxalate monohydrate, whereas other 56 % contained both monohydrate and dihydrate or usually their mixtures with hydroxyl apatite. Hypocitraturia, hypercalciuria and hyperuricosuria were identified as the most frequent disorders. Patients with pure calcium oxalate stones and calcium oxalate mixed with apatite revealed different patterns including age, acid-base balance of urine, calcium, citrate excretion etc. Our results demonstrate that most patients simultaneously reveal several risk factors. The special attention should be paid to normalize the daily citrate, calcium and urate excretion. High risk patients, such as postmenopausal females or stone formers with a high apatite content require a specific metabolic evaluation towards in highlighting abnormalities associated with stone formation.

Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.

Science.gov (United States)

Monico, Letizia; Rosi, Francesca; Miliani, Costanza; Daveri, Alessia; Brunetti, Brunetto G

2013-12-01

In this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome artworks analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the νs(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks. Copyright © 2013 Elsevier B.V. All rights reserved.

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...

Synthesis, characterization and study of some physical properties of some lanthanide complexes of salicylaldehyde oxal-dihydrazone

International Nuclear Information System (INIS)

Shrestha, S.; Rao, T.R.; Narang, K.K.; Shrestha, S.P.

2006-05-01

Some Lanthanoid complexes of the type [Ln (L-2H).A.H 2 O] [Ln = Y, La, Nd, Gd, Tb, Dy, A=OAc; and L = Salicyaldehyde oxal di-hydrazone] was synthesized and characterized by various physico- chemical techniques. Dehydration study at two specific temperatures (110 deg. C and 150 deg. C) indicates the presence of water molecules only in co-ordination sphere of the metal ion. IR, electronic spectra, DTA-TG have been recorded to establish the bonding sites of the ligand. All the complexes decomposed above and not melting up to 350 deg. C. The complexes are insoluble in any common organic solvent even in DMF and DMSO. Solid state electrical conductivities at various frequencies show a semiconducting nature of the complexes. Optical band gap measurement of the complex [Dy(SODH-2H).OAc.H 2 O] shows that complex behaves as direct band gap material. No well-defined peaks, except broad humps were observed in X-ray diffractogram of these complexes, indicating an amorphous nature of the complexes. (author)

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

Indian Academy of Sciences (India)

WINTEC

Institute of Diploma Studies, Nirma University of Science and Technology, Ahmedabad 384 481, India. MS received 29 ... dielectric response at various frequencies of applied field. ... 1987). Many oxalates exist in nature, for example, copper.

Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

International Nuclear Information System (INIS)

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 (H 2 O)] n ·2n(H 2 O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H 2 sfpip)(ox)(H 2 O) 4 ] n ·2n(H 2 O) (Ln=Nd (8) Sm (9)), [H 2 ox=oxalic acid, H 3 sfpip=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 H 3 sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox 2− 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. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

Energy Technology Data Exchange (ETDEWEB)

Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN; An, Ran; Yang, Meng-Lin; Xue, Ganglin

2017-01-15

Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox){sub 0.5}(H{sub 2}O)]{sub n}·2n(H{sub 2}O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H{sub 2}sfpip)(ox)(H{sub 2}O){sub 4}]{sub n}·2n(H{sub 2}O) (Ln=Nd (8) Sm (9)), [H{sub 2}ox=oxalic acid, H{sub 3}sfpip=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 H{sub 3}sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox{sup 2−} 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. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

Recovery of plutonium from oxalate supernatant using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

International Nuclear Information System (INIS)

Mohapatra, P.K.; Manchanda, V.K.; Gupta, K.K.; Singh, R.K.

1997-01-01

Extraction of Pu(IV) from oxalate supernatant was carried out employing varying concentrations of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP). Near quantitative extraction of Pu(IV) from an aqueous solution of 0.2M oxalic acid and 3M HNO 3 was possible employing 0.05M PMBP solution in xylene. Extraction studies at different uranium loading conditions were carried out and conditions for quantitative stripping were arrived at. (author). 2 refs., 4 tabs

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.

Heteropentanuclear Oxalato-Bridged nd–4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

KAUST Repository

Kuhn, Paul-Steffen

2015-08-10

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d–4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by 13C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)]2− are coordinated to YIII and DyIII, respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4]5− (Ln=Y, Dy). While YIII is eight-coordinate in 2, DyIII is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N+ ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2–5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d–4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2–5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d–4f metal complexes 6–9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.

Heteropentanuclear Oxalato-Bridged nd–4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

KAUST Repository

Kuhn, Paul-Steffen; Cremer, Laura; Gavriluta, Anatolie; Jovanović, Katarina K.; Filipović, Lana; Hummer, Alfred A.; Bü chel, Gabriel E.; Dojčinović, Biljana P.; Meier, Samuel M.; Rompel, Annette; Radulović, Siniša; Tommasino, Jean Bernard; Luneau, Dominique; Arion, Vladimir B.

2015-01-01

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d–4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by 13C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)]2− are coordinated to YIII and DyIII, respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4]5− (Ln=Y, Dy). While YIII is eight-coordinate in 2, DyIII is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N+ ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2–5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d–4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2–5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d–4f metal complexes 6–9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

A new approach to study cadmium complexes with oxalic acid in soil solution.

Science.gov (United States)

Dytrtová, Jana Jaklová; Jakl, Michal; Sestáková, Ivana; Zins, Emilie-Laure; Schröder, Detlef; Navrátil, Tomáš

2011-05-05

This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH(2)) were observed. In order to verify the possible formation of complexes with OAH(2), aqueous solutions of OAH(2) with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd(n)(X,Y)((2n+1))](-), where n is the number of cadmium atoms, X=Cl(-), and Y=OAH(-). Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

A new approach to study cadmium complexes with oxalic acid in soil solution

International Nuclear Information System (INIS)

Jaklova Dytrtova, Jana; Jakl, Michal; Sestakova, Ivana; Zins, Emilie-Laure; Schroeder, Detlef; Navratil, Tomas

2011-01-01

This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH 2 ) were observed. In order to verify the possible formation of complexes with OAH 2 , aqueous solutions of OAH 2 with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd n (X,Y) (2n+1) ] - , where n is the number of cadmium atoms, X = Cl - , and Y = OAH - . Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

A new approach to study cadmium complexes with oxalic acid in soil solution

Energy Technology Data Exchange (ETDEWEB)

Jaklova Dytrtova, Jana, E-mail: dytrtova@uochb.cas.cz [Institute of Organic Chemistry and Biochemistry of the AS CR, v.v.i., Flemingovo namesti 2, 16610 Prague 6 (Czech Republic); Jakl, Michal [Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamycka 129, 16521 Prague - Suchdol (Czech Republic); Sestakova, Ivana [J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 3, 182 23 Prague 8 (Czech Republic); Zins, Emilie-Laure; Schroeder, Detlef [Institute of Organic Chemistry and Biochemistry of the AS CR, v.v.i., Flemingovo namesti 2, 16610 Prague 6 (Czech Republic); Navratil, Tomas [J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 3, 182 23 Prague 8 (Czech Republic)

2011-05-05

This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH{sub 2}) were observed. In order to verify the possible formation of complexes with OAH{sub 2}, aqueous solutions of OAH{sub 2} with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd{sub n}(X,Y){sub (2n+1)}]{sup -}, where n is the number of cadmium atoms, X = Cl{sup -}, and Y = OAH{sup -}. Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

Structure and dynamics of solvated hydrogenoxalate and oxalate anions: theoretical study

Czech Academy of Sciences Publication Activity Database

Kroutil, O.; Minofar, Babak; Kabeláč, M.

2016-01-01

Roč. 22, č. 9 (2016), s. 210 ISSN 1610-2940 Institutional support: RVO:61388971 Keywords : Ab initio molecular dynamics * oxalic acid anions * Potential energy surface Subject RIV: EE - Microbiology, Virology Impact factor: 1.425, year: 2016

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

Comparative study of oxalic and malonic acid behaviour in the chemical cleaning of alloy 800 surfaces

International Nuclear Information System (INIS)

Garcia, Damian A.; Bruyere, Vivienne I.E.; Bordoni, Roberto A.; Olmedo, Ana M.; Morando, Pedro J.

2004-01-01

This work consisted, in a first stage, on a basic study of the dissolution mechanism of nickel ferrite in aqueous malonic acid. Powdered oxides (Ni x Fe 3-x O 4 ) were synthesized by wet procedures and heated at 750 C degrees. These oxides were characterized by conventional methods and dissolved under different experimental conditions (pH, reagent concentration, temperature, etc.) in order to determine the dissolution rates. Optimal dissolution conditions were explored and compared to the corresponding oxalic acid ones. In a second stage, these conditions were applied to oxides grown on Alloy 800 coupons. Before oxidation, all coupons were ground polished and then were exposed to hydrothermal conditions (350 C degrees, pH 25Cdegrees ≅ 10.4 -LiOH-, 20-22 days) in static autoclaves. Finally, oxidized and unoxidized coupons were treated with chemical solutions containing oxalic or malonic acid at conditions optimized in the first stage. These results were also compared to those obtained on coupons exposed to a commercial formulation, APAC (Alkaline Permanganate Ammonium Citrate), as a reference. The results on coupon descaling using APMAL (AP + Malonic), APOX (AP + oxalic) and the comparison with APAC leads to conclude that malonic acid is a reagent whose chemical behavior is much better than oxalic acid and comparable to commercial formulations. (author) [es

Synthesis of BaTiO3 powder from barium titanyl oxalate (BTO ...

Indian Academy of Sciences (India)

Unknown

the synthesis of BaTiO3 from the mixture of barium car- bonate and titanium dioxide employing microwave heat- ing. They observed that hypostoichiometric TiO2 (TiO2–x) reacted with BaCO3 in the presence of microwave field at temperature as low as 350°C to give the mixture of hexa- gonal and tetragonal forms of BaTiO3 ...

Mechanism of formation of oxalate concrements in the presence of ureaseproducing pathogens in urine (conception

Directory of Open Access Journals (Sweden)

Vozianov S.A.

2017-06-01

Full Text Available The aim of the study was to as¬certain the role of U.urealyticum in formation of phosphates and oxalates in kidneys and factors promoting this pro¬cess. The work represents the author’s conception of this process. There were fully examined 79 patients with nephro¬lithiasis with the aim to determine the species difference of pathogenic agents of the accompanying inflammatory process and there was compared the chemical structure of the removed concrements. There was stated the role of the urease-producing bacteria (P.mirabilis and U.urealyticum in the process of phosphate and oxalate lithogenesis and the accompanying factors, which initiate these reactions (urinary pH, endogenic urease, index of oxalic acid concentration. The work presents the comparative analysis of lithogenesis in the presence of accompanying bacteria of different taxonomic position. The authors’ conception of the role of U.urealyticum and P.mirabilis in lithogenesis has been elaborated.

synthesis and structures

Indian Academy of Sciences (India)

Priya Saxena

2017-08-29

Aug 29, 2017 ... to a single crystal X-ray diffraction study for 1, 2 and 4-7. Keywords. Sterically .... 2.2b Mono-Schiff base 2: A suspension of I (1.00 g,. 2.27 mmol) and ...... bridge Crystallographic Data Centre, CCDC, 12 Union. Road, Cambridge .... H-C 2014 Rational design and synthesis of porous poly- mer networks: ...

Poly[di-μ-aqua-diaquabis(μ7-oxalato-κ9O1:O1:O1,O2:O2:O2′:O2′,O1′:O1′calciumdicaesium

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Hamza Kherfi

2013-09-01

Full Text Available In the title compound, [CaCs2(C2O42(H2O4]n, the Ca2+ ion, lying on a twofold rotation axis, is coordinated by four O atoms from two oxalate ligands and two bridging water molecules in an octahedral geometry. The Cs+ ion is coordinated by seven O atoms from six oxalate ligands, one bridging water and one terminal water molecule. The oxalate ligand displays a scarce high denticity. The structure contains parallel chain units runnig along [10-1], formed by two edge-sharing Cs polyhedra connected by CsO9 polyhedra connected by a face-sharing CaO6 octahedron. These chains are further linked by the oxalate ligands to build up a three-dimensional framework. O—H...O hydrogen bonds involving the water molecules and the carboxylate O atoms enhance the extended structure.

Bilateral native nephrectomy to reduce oxalate stores in children at the time of combined liver-kidney transplantation for primary hyperoxaluria type 1.

Science.gov (United States)

Lee, Eliza; Ramos-Gonzalez, Gabriel; Rodig, Nancy; Elisofon, Scott; Vakili, Khashayar; Kim, Heung Bae

2018-05-01

Primary hyperoxaluria type-1 (PH-1) is a rare genetic disorder in which normal hepatic metabolism of glyoxylate is disrupted resulting in diffuse oxalate deposition and end-stage renal disease (ESRD). While most centers agree that combined liver-kidney transplant (CLKT) is the appropriate treatment for PH-1, perioperative strategies for minimizing recurrent oxalate-related injury to the transplanted kidney remain unclear. We present our management of children with PH-1 and ESRD on hemodialysis (HD) who underwent CLKT at our institution from 2005 to 2015. On chart review, three patients (2 girls, 1 boy) met study criteria. Two patients received deceased-donor split-liver grafts, while one patient received a whole liver graft. All patients underwent bilateral native nephrectomy at transplant to minimize the total body oxalate load. Median preoperative serum oxalate was 72 μmol/L (range 17.8-100). All patients received HD postoperatively until predialysis serum oxalate levels fell stores and may mitigate damage to the renal allograft.

pH Dependency of sclerotial development and pathogenicity revealed by using genetically defined oxalate-minus mutants of Sclerotinia sclerotiorum

Science.gov (United States)

The devastating plant pathogen Sclerotinia sclerotiorum produces copious (up to 50mM) amounts of oxalic acid, which, for over a quarter century, has been claimed as the pathogenicity determinant based on UV-induced mutants that concomitantly lost oxalate production and pathogenicity. Such a claim wa...

Structural Characterization and Magnetic Properties of Undoped and Ti-Doped ZnO Nanoparticles Prepared by Modified Oxalate Route

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Ekane Peter Etape

2018-01-01

Full Text Available Ti-doped zinc oxide and pure zinc oxide nanoparticles were synthesized by a modified oxalate route using Averrhoa carambola fruit juice as a natural source of oxalate. The characteristics of the precursors have been investigated by FTIR, TGA, and XRD. The results from the investigation revealed that the precursors are zinc oxalate and Ti-doped zinc oxalate which readily decompose at 450°C. The as-prepared precursors were calcined at 450°C for 4 hours, and the decomposition products have been characterized by XRD, SEM, EDX, and VSM. XRD results revealed crystallinity with hexagonal wurtzite structure, while the average grain size was found to be 26 nm for Ti-doped ZnO and 29 nm for ZnO, using calculations based on Debye-Scherrer equation. Furthermore, the morphological studies by SEM showed particle agglomeration, while the presence of Ti3+ in the zinc oxide lattice is indicated by EDS analysis. Finally the hysteresis loop from VSM results shows that Ti-doped ZnO exhibits ferromagnetism.

Study of Gel Growth Cobalt (II Oxalate Crystals as Precursor of Co3O4 Nano Particles

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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  |

Engineering nutritious proteins: improvement of stability in the designer protein MB-1 via introduction of disulfide bridges.

Science.gov (United States)

Doucet, Alain; Williams, Martin; Gagnon, Mylene C; Sasseville, Maxime; Beauregard, Marc

2002-01-02

Protein design is currently used for the creation of new proteins with desirable traits. In this laboratory the focus has been on the synthesis of proteins with high essential amino acid content having potential applications in animal nutrition. One of the limitations faced in this endeavor is achieving stable proteins despite a highly biased amino acid content. Reported here are the synthesis and characterization of two disulfide-bridged mutants derived from the MB-1 designer protein. Both mutants outperformed their parent protein MB-1 with their bridge formed, as shown by circular dichroism, size exclusion chromatography, thermal denaturation, and proteolytic degradation experiments. When the disulfide bridges were cleaved, the mutants' behavior changed: the mutants significantly unfolded, suggesting that the introduction of Cys residues was deleterious to MB-1-folding. In an attempt to compensate for the mutations used, a Tyr62-Trp mutation was performed, leading to an increase in bulk and hydrophobicity in the core. The Trp-containing disulfide-bridged mutants did not behave as well as the original MB-1Trp, suggesting that position 62 might not be adequate for a compensatory mutation.

Synthesis of nanocrystalline materials through reverse micelles: A ...

Indian Academy of Sciences (India)

Wintec

precursors were heated to form their respective oxides. Mixture of ... oxychloride and 0⋅1 M zinc nitrate solution for cerium oxalate, zirconium oxalate and zinc oxalate, respectively. The other contained 0⋅1 M solution of ammonium oxalate.

Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents

International Nuclear Information System (INIS)

Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming

2014-01-01

Highlights: • Synthesis of highly phosphonic acid functionalized benzene-bridged PMOs. • Phosphonic acid loaded PMOs as adsorbent for cationic and anionic dyes. • Due to electrostatic interaction the adsorbent has high dye adsorption capacity. • π–π stacking interaction between benzene and dye enhances adsorption capacity. • Intraparticle diffusion played a dominant role in the adsorption process. - Abstract: Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π–π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles

Oxalic acid overproduction by copper-tolerant brown-rot basidiomycetes on southern yellow pine treated with copper-based preservatives

Science.gov (United States)

Carol A. Clausen; Frederick Green

2003-01-01

Accumulation of oxalic acid (OA) by brown-rot fungi and precipitation of copper oxalate crystals in wood decayed by copper-tolerant decay fungi has implicated OA in the mechanism of copper tolerance. Understanding the role of OA in copper tolerance is important due to an increasing reliance on copper-based wood preservatives. In this study, four copper-tolerant brown-...

Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

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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.

The Response of Paraburkholderia terrae Strains to Two Soil Fungi and the Potential Role of Oxalate

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Irshad Ul Haq

2018-05-01

Full Text Available Fungal-associated Paraburkholderia terrae strains in soil have been extensively studied, but their sensing strategies to locate fungi in soil have remained largely elusive. In this study, we investigated the behavior of five mycosphere-isolated P. terrae strains [including the type-3 secretion system negative mutant BS001-ΔsctD and the type strain DSM 17804T] with respect to their fungal-sensing strategies. The putative role of oxalic acid as a signaling molecule in the chemotaxis toward soil fungi, as well as a potential carbon source, was assessed. First, all P. terrae strains, including the type strain, were found to sense, and show a chemotactic response toward, the different levels of oxalic acid (0.1, 0.5, and 0.8% applied at a distance. The chemotactic responses were faster and stronger at lower concentrations (0.1% than at higher ones. We then tested the chemotactic responses of all strains toward exudates of the soil fungi Lyophyllum sp. strain Karsten and Trichoderma asperellum 302 used in different dilutions (undiluted, 1:10, 1:100 diluted versus the control. All P. terrae strains showed significant directed chemotactic behavior toward the exudate source, with full-strength exudates inciting the strongest responses. In a separate experiment, strain BS001 was shown to be able to grow on oxalate-amended (0.1 and 0.5% mineral medium M9. Chemical analyses of the fungal secretomes using proton nuclear magnetic resonance (1H NMR, next to high-performance liquid chromatography (HPLC, indeed revealed the presence of oxalic acid (next to glycerol, acetic acid, formic acid, and fumaric acid in the supernatants of both fungi. In addition, citric acid was found in the Lyophyllum sp. strain Karsten exudates. Given the fact that, next to oxalic acid, the other compounds can also serve as C and energy sources for P. terrae, the two fungi clearly offer ecological benefits to this bacterium. The oxalic acid released by the two fungi may have

Novel approach to recover cobalt and lithium from spent lithium-ion battery using oxalic acid

Energy Technology Data Exchange (ETDEWEB)

Zeng, Xianlai; Li, Jinhui, E-mail: jinhui@tsinghua.edu.cn; Shen, Bingyu

2015-09-15

Highlights: • Short-cut recovery of cobalt and lithium was directly obtained using oxalic acid. • Short-cut recovery process was optimized for a high recovery rate. • Leaching process was controlled by chemical reaction. • Leaching order of the sampling LiCoO{sub 2} using oxalic acid was first proposed. - Abstract: 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{sup −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 (LiCoO{sub 2}) using oxalic acid, and the leaching order of the sampling LiCoO{sub 2} 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.

Morphology-control of VO2 (B) nanostructures in hydrothermal synthesis and their field emission properties

International Nuclear Information System (INIS)

Yin Haihong; Yu Ke; Zhang Zhengli; Zhu Ziqiang

2011-01-01

VO 2 (B) nanostructures were synthesized via a facile hydrothermal process using V 2 O 5 as source material and oxalic acid as reductant. Three nanostructures of nanorods, nanocarambolas and nanobundles were found existing in the products, and a continuous changing of morphology was found in the synthesis process, during which the proportion of these three types of nanostructures can be adjusted by altering the concentrations of oxalic acid. The microstructures were evaluated using X-ray diffraction and scanning and transmission electron microscopies, respectively. FE properties measurement of these three types of nanostructures showed that the nanobundles have the best field emission performance with a turn-on field of ∼1.4 V/μm and a threshold field of ∼5.38 V/μm. These characteristics make VO 2 (B) nanostructures a competitive cathode material in field emission devices.

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

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B. Zobrist

2006-01-01

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 and 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.

Kinetics and mechanism of the oxidation of formic and oxalic acids ...

Indian Academy of Sciences (India)

Unknown

The organic acids were commercial products of the highest degree of purity .... reaction is not complete even at high concentration of ZnCl2, and that only the ... activation in the oxidation of oxalic acid suggests the involvement of both the ...

Multiscale structural characterizations of mixed U(iv)-An(iii) oxalates (An(iii) = Pu or Am) combining XAS and XRD measurements.

Science.gov (United States)

Arab-Chapelet, B; Martin, P M; Costenoble, S; Delahaye, T; Scheinost, A C; Grandjean, S; Abraham, F

2016-04-28

Mixed actinide(III,IV) oxalates of the general formula M2.2UAn(C2O4)5·nH2O (An = Pu or Am and M = H3O(+) and N2H5(+)) have been quantitatively precipitated by oxalic precipitation in nitric acid medium (yield >99%). Thorough multiscale structural characterization using XRD and XAS measurements confirmed the existence of mixed actinide oxalate solid solutions. The XANES analysis confirmed that the oxidation states of the metallic cations, tetravalent for uranium and trivalent for plutonium and americium, are maintained during the precipitation step. EXAFS measurements show that the local environments around U(+IV), Pu(+III) and Am(+III) are comparable, and the actinides are surrounded by ten oxygen atoms from five bidentate oxalate anions. The mean metal-oxygen distances obtained by XAS measurements are in agreement with those calculated from XRD lattice parameters.

Preparation of nuclear purity beryllium oxalate tri-hydrate; Preparation d'oxalate de beryllium trihydrate de purete nucleaire

Energy Technology Data Exchange (ETDEWEB)

Delcorte, M; Lecocq, A; Rigaud, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1964-07-01

In this report we have gathered the whole of the knowledge acquired by our group during the campaign for preparation of beryllium oxalate we carried out through the first half year of 1962. The reader shall find in the first place information and bibliographic data gathered by Miss OLLIVIER, documentalist of the Section d'Etudes, Recherches et Applications Chimiques. We then describe the original process perfected in the laboratories, and the production techniques we employed for the semi-large operative units. Finally, we publish the results we obtained on one hand on the chemical aspect, in the industrial meaning of the term, which is to-day concerning the ponderal output, on the other hand on the analytical aspect as you can evidently not dissociate the quantity of substance produced from its purity. (authors) [French] Nous avons reuni dans ce document l'ensemble des connaissances acquises par notre groupe pendant la campagne de preparation d'oxalate de beryllium que nous avons effectuee au cours du 1er semestre 1962. Le lecteur y trouvera en premier lieu les renseignements et donnees bibliographiques rassembles par Mlle OLLIVIER, documentaliste a la Section d'Etudes, Recherches et Applications Chimiques. Nous decrivons ensuite le procede original mis au point dans les laboratoires et les techniques de fabrication que nous avons utilisees pour des unites operatoires demi-grand. Pour terminer nous publions les resultats obtenus, d'une part sur le plan chimique, au sens industriel du terme, c'est-a-dire du point de vue rendement ponderal, d'autre part sur le plan analytique puisqu'on ne peut evidemment pas dissocier la quantite de produit fabrique, de sa purete. (auteurs)

X-ray fluorescence analysis of neodymium oxide/oxalate for rare earth impurities

International Nuclear Information System (INIS)

Chandola, L.C.; Mohile, A.N.

1977-01-01

An X-ray fluorescence method for the determination of cesium, praseodymium, samarium, europium and gadolinium in pure neodymium oxide and oxalate is described. The oxide sample is converted to oxalate and mixed with a binder (boric acid) to obtain a pressed circular pellet. The amount of sample needed for analysis is reduced by making use of the double layer pellet technique. A tungsten target X-ray tube is employed to irradiate the sample and a Philips PW 1220 semiautomatic X-ray spectrometer with a LiF (200) crystal is used to analyse the fluorescent X-rays. The minimum determination limit is 0.01 percent for all rare earths determined except for europium for which the limit is 0.005 percent. Three sigma detection limits have been calculated. (author)

Recovery of Iron from Pyrolusite Leaching Slag by a Lab-Scale Circulation Process of Oxalic Acid Leaching and Ultraviolet Irradiation

Directory of Open Access Journals (Sweden)

Biao Deng

2017-12-01

Full Text Available Pyrolusite leaching slag is a Fe-containing slag generated from pyrolusite leaching process with SO2. Recovery of iron from the slag not only has economic benefit, but also prevents the secondary pollution to the environment. A novel lab-scale cyclic process for recovering iron from pyrolusite leaching slag was introduced. The process contains two steps: (1 iron was leached with oxalic acid and [Fe(C2O4n](3−2n+ solution was generated; (2 the [Fe(C2O4n](3−2n+ solution was irradiated by ultraviolet and ferrous oxalate precipitation were obtained. The effect of operation parameter on leaching and irradiation process were studied separately. In the leaching process, the optimal solid/liquid ratio, oxalic acid concentration, leaching temperature, stirring rate, and leaching time are 1:50, 0.40 mol/L, 95 °C, 300 r/min, and 3 h, respectively. In the irradiation process, the best irradiation wavelength, Fe/oxalic acid molar ratio and irradiation time are 254 nm, 1:4, and 30 min. Besides, a test of 9 continuous cycles was carried out and the performance and material balance of the combined process were investigated. The results showed that the cyclic process is entirely feasible and prove to be stable producing, and ferrous oxalate of 99.32% purity. Material balance indicated that 95.17% of iron was recovered in the form of FeC2O4·2H2O, and the recovery efficiency of oxalic acid was 58.52%.

47 CFR 80.331 - Bridge-to-bridge communication procedure.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

Sky-blue emitting bridged diiridium complexes: beneficial effects of intramolecular π-π stacking.

Science.gov (United States)

Congrave, Daniel G; Hsu, Yu-Ting; Batsanov, Andrei S; Beeby, Andrew; Bryce, Martin R

2018-02-06

The potential of intramolecular π-π interactions to influence the photophysical properties of diiridium complexes is an unexplored topic, and provides the motivation for the present study. A series of diarylhydrazide-bridged diiridium complexes functionalised with phenylpyridine (ppy)-based cyclometalating ligands is reported. It is shown by NMR studies in solution and single crystal X-ray analysis that intramolecular π-π interactions between the bridging and cyclometalating ligands rigidify the complexes leading to high luminescence quantum efficiencies in solution and in doped films. Fluorine substituents on the phenyl rings of the bridge promote the intramolecular π-π interactions. Notably, these non-covalent interactions are harnessed in the rational design and synthesis of the first examples of highly emissive sky-blue diiridium complexes featuring conjugated bridging ligands, for which they play a vital role in the structural and photophysical properties. Experimental results are supported by computational studies.

Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR

Directory of Open Access Journals (Sweden)

Andrea Testino

2015-06-01

Full Text Available Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR, has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1−xNixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO42 nanoparticles (NPs can be obtained with a production rate of about 1–10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.

Science.gov (United States)

Zhao, Cen; Arroyo-Mora, Luis E; DeCaprio, Anthony P; Sharma, Virender K; Dionysiou, Dionysios D; O'Shea, Kevin E

2014-12-15

Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (OH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.19 ± 0.12 and 0.30 ± 0.01 μM/min, respectively. The steady-state concentration of hydroxyl radical (OH) for the Fe(III)-oxalate/H2O2/UV (350 nm) conditions was 10.88 ± 1.13 × 10(-14) M and 2.7 ± 0.1 × 10(-14) M for the Fe(III)-oxalate/H2O2/visible (450 nm). The rate of superoxide anion radical (O2(-)) production under Fe(III)-oxalate/H2O2/UV (350 nm) was 0.19 ± 0.02 μM/min with a steady-state concentration of 5.43 ± 0.473 × 10(-10) M. Detailed product studies using liquid chromatography coupled to Q-TOF/MS demonstrate both reduction (multiple dehalogenations) and oxidation (aromatic ring and side chains) contribute to the degradation pathways. The reduction processes appear to be initiated by the carbon dioxide anion radical (CO2(-)) while oxidation processes are consistent with OH initiated reaction pathways. Unlike most advanced oxidation processes the Fe(III)-oxalate/H2O2/photochemical system can initiate to both reductive and oxidative degradation processes. The observed reductive dehalogenation is an attractive remediation strategy for halogenated organic compounds as the process can dramatically reduce the formation of the problematic disinfection by-products often associated with oxidative treatment processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

A review of plutonium oxalate decomposition reactions and effects of decomposition temperature on the surface area of the plutonium dioxide product

International Nuclear Information System (INIS)

Orr, R.M.; Sims, H.E.; Taylor, R.J.

2015-01-01

Plutonium (IV) and (III) ions in nitric acid solution readily form insoluble precipitates with oxalic acid. The plutonium oxalates are then easily thermally decomposed to form plutonium dioxide powder. This simple process forms the basis of current industrial conversion or ‘finishing’ processes that are used in commercial scale reprocessing plants. It is also widely used in analytical or laboratory scale operations and for waste residues treatment. However, the mechanisms of the thermal decompositions in both air and inert atmospheres have been the subject of various studies over several decades. The nature of intermediate phases is of fundamental interest whilst understanding the evolution of gases at different temperatures is relevant to process control. The thermal decomposition is also used to control a number of powder properties of the PuO_2 product that are important to either long term storage or mixed oxide fuel manufacturing. These properties are the surface area, residual carbon impurities and adsorbed volatile species whereas the morphology and particle size distribution are functions of the precipitation process. Available data and experience regarding the thermal and radiation-induced decompositions of plutonium oxalate to oxide are reviewed. The mechanisms of the thermal decompositions are considered with a particular focus on the likely redox chemistry involved. Also, whilst it is well known that the surface area is dependent on calcination temperature, there is a wide variation in the published data and so new correlations have been derived. Better understanding of plutonium (III) and (IV) oxalate decompositions will assist the development of more proliferation resistant actinide co-conversion processes that are needed for advanced reprocessing in future closed nuclear fuel cycles. - Highlights: • Critical review of plutonium oxalate decomposition reactions. • New analysis of relationship between SSA and calcination temperature. • New SEM

VHDL for logic synthesis

CERN Document Server

Rushton, Andrew

2011-01-01

Many engineers encountering VHDL (very high speed integrated circuits hardware description language) for the first time can feel overwhelmed by it. This book bridges the gap between the VHDL language and the hardware that results from logic synthesis with clear organisation, progressing from the basics of combinational logic, types, and operators; through special structures such as tristate buses, register banks and memories, to advanced themes such as developing your own packages, writing test benches and using the full range of synthesis types. This third edition has been substantially rewritten to include the new VHDL-2008 features that enable synthesis of fixed-point and floating-point hardware. Extensively updated throughout to reflect modern logic synthesis usage, it also contains a complete case study to demonstrate the updated features. Features to this edition include: * a common VHDL subset which will work across a range of different synthesis systems, targeting a very wide range of technologies...

Kinetic study of nucleation and crystal growth during oxalic precipitation in the nuclear industry

International Nuclear Information System (INIS)

Andrieu, Murielle

1999-01-01

In spite of an extensive use in chemical industry, most of precipitation processes are based on global and empirical knowledge. However, in the recent years, fundamental and phenomenological theories have been developed and they can be used to better understand the mechanisms of precipitation of plutonium IV oxalate, which is a significant stage of the irradiated fuel reprocessing. For this reason, appropriate methods were developed to study nucleation and crystal growth kinetics in a nuclear environment under a wide range of operating conditions. Each phenomena was studied individually in order to reduce the free parameters of the System. This study bears on the oxalates of plutonium and elements which simulate plutonium behaviour during the precipitation, neodymium III and uranium IV. A compact apparatus of a specific construction was used for nucleation measurements in accordance with the Nielsen's method. The state of the mixing was characterised at the reactor scale (macro-mixing) and at molecular scale (micro-mixing). The experimental results for the studied oxalates are in good agreement with the Volmer and Weber's theory. We propose primary nucleation kinetic laws over a wide range of operating conditions (temperature, non-stoichiometric conditions, acidity...). An original method, using a high seed charge, was developed for the determination of crystal growth kinetics, in a batch crystallizer. The crystal growth rate is first order with respect to the supersaturation and the kinetic constant follows an Arrhenius type relation with activation energies of 14, 29 and 36 kJ.mol -1 for respectively neodymium III, uranium IV and plutonium IV oxalates. The overall growth process is surface integration controlled, with a screw dislocation mechanism. [fr

Effect of feeding various forms of oxalate on the rumen metabolism and the fate of calcium in buffalo (Bubalus bubalis) calves

International Nuclear Information System (INIS)

Saddi, L.K.; Ahuja, S.P.; Sareen, V.K.; Singh, Sudarshan; Bhatia, I.S.

1978-01-01

The degradation of 45 Ca oxalate in the rumen and the absorption of 45 Ca released (experiment 2), the production of bicarbonates and TVFA in the rumen, and the rumen pH value (experiment 1) were studied in male buffalo calves consuming paddy straw (group 1), wheat straw supplemented with calcium oxalate (group 2) and wheat straw supplemented with calcium oxalate plus potassium oxalate (group 3). The radioactivity 1n the blood appeared with 1 hr in all the animals. Maximum 45 Ca specific activity in the blood was observed at 18,24 and 36 hr in groups 1 to 3, respectively, after intraruminal infusion of 15 mCi 45 Ca oxalate. Paddy-straw feeding caused polyurea. In all the animals the very first micturition showed the presence of radioactivity, and maximum 45 Ca specific activity in the urine and feaces was obtained around 31 and 25 hr, respectively, after infusion. However, during the following 5 days, the decline in 45 Ca specific activity in the feaces was sharper in group 1 than in the other groups indicating less absorption of calcium in group 1. Higher bicarbonates contents and pH of the rumen fluid were observed in group 3. The results indicated a slow and continuous release of oxalates from paddy straw. The ruminal TVFA concentration was lower and pH was relatively higher in group 3. Group 1 showed uniformly higher amounts of TVFA. (auth.)

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.

Efficiency and resistance of the artificial oxalate protection treatment on marble against chemical weathering

International Nuclear Information System (INIS)

Doherty, B.; Pamplona, M.; Selvaggi, R.; Miliani, C.; Matteini, M.; Sgamellotti, A.; Brunetti, B.

2007-01-01

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

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.

Preventive treatment of calcium oxalate crystal deposition with immortal flowers.

Science.gov (United States)

Orhan, Nilüfer; Onaran, Metin; Şen, İlker; Işık Gönül, İpek; Aslan, Mustafa

2015-04-02

A number of medicinal plants are used for their diuretic, urolithiatic and anti-inflammatory effects on urinary system problems in Turkey and the most common traditional remedy for kidney stones is the tea of immortal flowers. The aim of this study is to evaluate the preventive effect of infusions prepared from capitulums of Helichrysum graveolens (M.Bieb.) Sweet (HG) and Helichrysum stoechas ssp. barellieri (Ten.) Nyman (HS) on formation of kidney stones. Sodium oxalate (Ox-70mg/kg intraperitoneally) was used to induce kidney stones on Wistar albino rats. At the same time, two different doses of the plant extracts (HG: 62.5 and 125mg/kg; HS: 78 and 156mg/kg) were dissolved in the drinking water and administered to animals for 5 days. Potassium citrate was used as positive control in the experiments. During the experiment, water intake, urine volume and body weights of the animals were recorded. At the end of the experiments, liver, kidney and body weights of the animals were determined; biochemical analysis were conducted on urine, blood and plasma samples. Histopathological changes in kidney tissues were examined and statistical analysis were evaluated. HS extract showed the highest preventive effect at 156mg/kg dose (stone formation score: 1.16), whereas a number of kidney stones were maximum in sodium oxalate group (stone formation score: 2.66). Helichrysum extracts decreased urine oxalate and uric acid levels and increased citrate levels significantly. In addition, Helichrysum extracts regulated the negative changes in biochemical and hematological parameters occurred after Ox injection. We conclude that Helichrysum extracts could reduce the formation and growth of kidney stones in Ox-induced urolithiasis and can be beneficial for patients with recurrent stones. In addition, this is the first study on the preventive effect of immortal flowers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Synthesis and X-ray diffraction study of new uranyl malonate and oxalate complexes with carbamide

International Nuclear Information System (INIS)

Medvedkov, Ya. A.; Serezhkina, L. B.; Grigor’ev, M. S.; Serezhkin, V. N.

2016-01-01

Two new malonate-containing uranyl complexes with carbamide of the formulas [UO 2 (C 3 H 2 O 4 )(Urea) 2 ] (I) and [UO 2 (C 3 H 2 O 4 )(Urea) 3 ] (II), where Urea is carbamide, and one uranyl oxalate complex of the formula [UO 2 (C 2 O 4 )(Urea) 3 ] (III) were synthesized, and their crystals were studied by X-ray diffraction. The main structural units in crystals I are the electroneutral chains [UO 2 (C 3 H 2 O 4 )(Urea) 2 ] ∞ belonging to the crystal-chemical group AT 11 M 2 1 (A = UO 2 2+ , T 11 = C 3 H 2 O 4 2- , M 1 = Urea) of uranyl complexes. Crystals II and III are composed of the molecular complexes [UO 2 (L)(Urea) 3 ], where L = C 3 H 2 O 4 2- or C 2 O 4 2- , belonging to the crystal-chemical group AB 01 M 3 1 (A = UO 2 2+ , B 01 = C 3 H 2 O 4 2- or C 2 O 4 2- , M 1 = Urea). The characteristic features of the packing of the uranium-containing complexes are discussed in terms of molecular Voronoi–Dirichlet polyhedra. The effect of the Urea: U ratio on the structure of uranium-containing structural units is considered.

Effect of Copper Nanoparticles Dispersion on Catalytic Performance of Cu/SiO2 Catalyst for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

Directory of Open Access Journals (Sweden)

Yajing Zhang

2013-01-01

Full Text Available Cu/SiO2 catalysts, for the synthesis of ethylene glycol (EG from hydrogenation of dimethyl oxalate (DMO, were prepared by ammonia-evaporation and sol-gel methods, respectively. The structure, size of copper nanoparticles, copper dispersion, and the surface chemical states were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, temperature-programmed reduction (TPR, and X-ray photoelectron spectroscopy (XPS and N2 adsorption. It is found the structures and catalytic performances of the catalysts were highly affected by the preparation method. The catalyst prepared by sol-gel method had smaller average size of copper nanoparticles (about 3-4 nm, better copper dispersion, higher Cu+/C0 ratio and larger BET surface area, and higher DMO conversion and EG selectivity under the optimized reaction conditions.

Synthesis and characteristics of a novel 3-D organic amine oxalate: (enH2)1.5[Bi3(C2O4)6(CO2CONHCH2CH2NH3)].6.5H2O

International Nuclear Information System (INIS)

Yu Xiaohong; Zhang Hanhui; Cao Yanning; Chen Yiping; Wang Zhen

2006-01-01

A novel 3-D compound of (enH 2 ) 1.5 [Bi 3 (C 2 O 4 ) 6 (CO 2 CONHCH 2 CH 2 NH 3 )].6.5H 2 O has been hydrothermally synthesized and characterized by IR, ultraviolet-visible diffuse reflection integral spectrum (UV-Vis DRIS), fluorescence spectra, TGA and single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=31.110(8)A, b=11.544(3)A, c=22.583(6)A, β=112.419(3) o , V=7497(3)A 3 , Z=8, R 1 =0.0463 and wR 2 =0.1393 for unique 7686 reflections I>2σ(I). In the title compound, the Bi atoms have eight-fold and nine-fold coordination with respect to the oxygen atoms, with the Bi atoms in distorted dodecahedron and monocapped square antiprism, respectively. The 3-D framework of the title compound contains channels and is composed of linkages between Bi atoms and oxalate units, forming honeycomb-like layers with two kinds of 6+6 membered aperture, and pillared by oxalate ligands and monamide groups. The channels have N-ethylamine oxalate monamide group - CO 2 CONHCH 2 CH 2 NH 3 + , which is formed by the in situ reaction of en and oxalate acid. At room temperature, the complex exhibits intense blue luminescence with an emission peak at 445nm

In vitro dissolution of calcium oxalate stones with ethylenediaminetetraacetic acid and snake venom thrombin-like enzyme.

Science.gov (United States)

Zhou, Xiang-Jun; Zhang, Jie; Zhang, Ci; Xu, Chang-Geng

2014-01-01

The aim of this study was to determine the feasibility of using snake venom thrombin-like enzyme (SVTLE) and/or ethylenediaminetetraacetic acid (EDTA) to dissolve calcium oxalate stones in vitro. Seven calcium oxalate stones were incubated with various chemolytic agents [EDTA, Tris-HCl/EDTA (TE) buffer or SVTLE diluted in TE buffer]. The pH, calcium concentration, stone weight and stone surface integrity were recorded, as well as related pathological changes to bladder mucosae. Compared to all other solutions, those containing SVTLE and buffered EDTA had higher concentrations of mobilized calcium and caused significantly more stone weight loss, stone fragility and gaps in the calcium crystals. Also, there were no adverse pathological effects on rabbit bladder mucosae from any of the solutions. The data indicate that buffered EDTA and SVTLE can be used to dissolve calcium oxalate stones and, at the concentrations used here, do not damage tissue. 2013 S. Karger AG, Basel.

Synthesis of LiBOB Fine Powder to Increase Solubility

Directory of Open Access Journals (Sweden)

Etty Marti Wigayati

2017-04-01

Full Text Available Lithium bis (oxalate borate or LiBOB compound has captured interest of researchers, because it is potentially viable to be used as electrolyte salt in lithium-ion battery system. This compound is easy to synthesize and considered to be more environmentally friendly compared to conventional electrolyte salt because LiBOB does not contain halogen element. This research focused on the synthesis of LiBOB fine powder, which main purpose is improving LiBOB salt solubility in liquid electrolyte solution. This will aid the ion transfer between electrodes which in turn will increase the electrolyte performance. Solid state reaction was employed in this experiment. Synthesis of LiBOB compound was performed by reacting oxalic acid dihydrate, lithium hydroxide monohydrate, and boric acid. The resulting powder was then processed into fine powder using ball milling technique with varying milling time (0, 6, 10, and 13 hour. Microstructure of the sample was then analyzed to obtain information regarding phase formation, functional groups, grain surface morphology, surface area, pore volume, solubility, and ionic conductivity. The analysis shown that LiBOB and LiBOB hydrate phase was formed during the reaction, there was no changed in existing phase during milling process, crystallinity index was shifted to lower value but there was no difference in functional groups. Highest value in surface area was found to be 83.11 m2/g, with pore volume of 1.21311e+02 A at 10 hours milling. Smaller powder size resulted in higher solubility, unfortunately the ionic conductivity was found to be decreased.

Molecular Fluoride-Bridged 3d-4f Complexes and Their Magnetic Properties

DEFF Research Database (Denmark)

Pedersen, K. S.; Bendix, J.

2016-01-01

trifluorides with very high lattice enthalpies, building block approaches are not limited to robust systems and use of labile transition metal fluoride complexes has met with unexpected success. The physical properties of fluoride-bridged 3d-4f systems are crucially dependent on coordination geometries, which...... be utilized efficiently in tailored synthesis of polynuclear complexes and extended structures. In particular, the strong affinity of the lanthanides for fluoride makes it a good choice for directed synthesis of mixed lanthanide-transition metal complexes. Despite the competition from formation of lanthanide...

Studies on the preparation of thorium metal sponge from thorium oxalate

International Nuclear Information System (INIS)

Vijay, P.L.; Sehra, J.C.; Sundaram, C.V.; Gurumurthy, K.R.; Raghavan, R.V.

1978-01-01

The results of investigations carried out on the production of high purity thorium metal sponge, starting with thorium oxalate are presented. The flow sheet includes chlorination of thorium oxalate, purification of raw thorium tetrachloride, magnesium reduction of anhydrous thorium tetrachloride, slag metal separation, vacuum distillation for removal of residual MgCl 2 and excess magnesium, and consolidation of the metal sponge. Studies have been carried out to investigate the optimum chlorination efficiency and chlorine utilization attainable using different chlorinating agents, and to compare the quality of the sponge obtained with single and double distilled chloride. The overall process efficiency under optimum conditions was 81%. The thorium metal button, prepared from the sponge by arc-melting, analysed : O 2 - 847, N 2 - 20, C - 179, Mg - 100, Fe - 49, Ni<50, Al - 11, Cr - 7 (expressed in parts per million parts of thorium). The button could be further purified by electron beam melting to improve its ductility. (author)

Lanthanum and yttrium oxysulfides activated by europium: (Ln1-x Eux)2 O2 S - Synthesis and characterization

International Nuclear Information System (INIS)

Luiz, J.M.

1989-01-01

The synthesis of lanthanum and yttrium oxysulfides activated by europium were obtained by thermal decomposition of lanthanum and yttrium oxalates doped with europium, under an argon and sulphur atmosphere. The thermal decomposition of these compounds is studied by differential thermal analysis (DTA). The characterization of these oxysulfides were made by chemical analyses, infrared spectroscopy, X-ray diffraction, scanning electron microscopy and emission spectroscopy. (M.V.M.)

Dynamic process model of a plutonium oxalate precipitator

International Nuclear Information System (INIS)

Borgonovi, G.M.; Hammelman, J.E.; Miller, C.L.

1980-01-01

A dynamic model of a plutonium oxalate precipitator is developed to provide a means of predicting plutonium inventory on a continuous basis. The model is based on state-of-the-art crystallization equations, which describe nucleation and growth phenomena. The model parameters were obtained through the use of batch experimental data. The model has been used to study the approach to steady state, to investigate the response to input transients, and to simulate the control of the precipitation process. 12 refs

Tetra­kis(aceto­nitrile)copper(I) hydrogen oxalate–oxalic acid–aceto­nitrile (1/0.5/0.5)

Science.gov (United States)

Royappa, A. Timothy; Stepherson, Jacob R.; Vu, Oliver D.; Royappa, Andrew D.; Stern, Charlotte L.; Müller, Peter

2013-01-01

In the title compound, [Cu(CH3CN)4](C2HO4)·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four aceto­nitrile ligands in a slightly distorted tetra­hedral environment. The oxalic acid mol­ecule lies across an inversion center. The aceto­nitrile solvent mol­ecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid mol­ecules are linked via O—H⋯O hydrogen bonds, forming chains along [010]. PMID:24098175

Solution Synthesis and Processing of PZT Materials for Neutron Generator Applications

Energy Technology Data Exchange (ETDEWEB)

Anderson, M.A.; Ewsuk, K.G.; Montoya, T.V.; Moore, R.H.; Sipola, D.L.; Tuttle, B.A.; Voigt, J.A.

1998-12-01

A new solution synthesis route has been developed for the preparation of lead-based ferroelectric materials (patent filed). The process produces controlled stoichiometry precursor powders by non-aqueous precipitation. For a given ferroelectric material to be prepared, a metal acetate/alkoxide solution containing constituent metal species in the appropriate ratio is mixed with an oxalic acid/n-propanol precipitant solution. An oxalate coprecipitate is instantly fonned upon mixing that quantitatively removes the metals from solution. Most of the process development was focused on the synthesis and processing of niobium-substituted lead zirconate titanate with a Zr-to-Ti ratio of 95:5 (PNZT 95/5) that has an application in neutron generator power supplies. The process was scaled to produce 1.6 kg of the PNZT 95/5 powder using either a sen-ii-batch or a continuous precipitation scheme. Several of the PNZT 95/5 powder lots were processed into ceramic slug form. The slugs in turn were processed into components and characterized. The physical properties and electrical performance (including explosive functional testing of the components met the requirements set for the neutron generator application. Also, it has been demonstrated that the process is highly reproducible with respect to the properties of the powders it produces and the properties of the ceramics prepared from its powders. The work described in this report was funded by Sandia's Laboratory Directed Research and Development Program.

Growth and study of barium oxalate single crystals in agar gel

Indian Academy of Sciences (India)

Unknown

tive Powder Diffraction Data Interpretation and Indexing. Program, Version 2.2) was used to calculate 'd' values. Calculated 'd' values matched with reported values. Table. 2 shows calculated unit cell parameters. Table 2. Calculated unit cell parameters. Parameters. Barium oxalate. System. Monoclinic (P) a. 8⋅2426 Å b.

Growth and study of barium oxalate single crystals in agar gel

Indian Academy of Sciences (India)

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 ...

Low-frequency magnetic field effect on solubility of oxalate type human organominerals in water in vitro

Directory of Open Access Journals (Sweden)

PopkovV.M.

2012-09-01

Full Text Available The research goal is to determine low-frequency AMF effect on dissolution of urinary stone material in vitro in water with human urinary stones (oxalate type. Materials and Methods. The structural changes in aqueous solutions may occur when exposed to low-frequency alternating magnetic fields (AMF. It depends on chemical composition of the solutions under the study. Results. Organic components (63.1 %, leading to the density decrease of the solution, urea (18.8%, leading to its increase, and oxalic acid (19.7% have been determined in stone composition. The decrease of transmittance T (% by the time of oxalate dissolution has indicated increase in concentration of dissolved sample. The sample has been exposed to AMF of 2-9 Hz on the background of the control sample. The growth of this dependence with AMF increasing of 11-22 Hz has established less concentration of dissolved sample in the test solution than in the control one. Conclusion. The main task has been to determine the influence of AMF of 2-22 Hz on solubility of urinary stones placed in water for an hour. The article is to conclude that maximal solubility of oxalate mineral sample by AMF of 2-22 Hz has been reached. It is 14% more than in the control solution. The effectiveness of AMF influence on solubility of organomineral decreases with frequency increasing. It has been confirmed by photometric and areometric measurements.

Membrane inlet mass spectrometry reveals that Ceriporiopsis subvermispora bicupin oxalate oxidase is inhibited by nitric oxide.

Science.gov (United States)

Moomaw, Ellen W; Uberto, Richard; Tu, Chingkuang

2014-07-18

Membrane inlet mass spectrometry (MIMS) uses a semipermeable membrane as an inlet to a mass spectrometer for the measurement of the concentration of small uncharged molecules in solution. We report the use of MIMS to characterize the catalytic properties of oxalate oxidase (E.C. 1.2.3.4) from Ceriporiopsis subvermispora (CsOxOx). Oxalate oxidase is a manganese dependent enzyme that catalyzes the oxygen-dependent oxidation of oxalate to carbon dioxide in a reaction that is coupled with the formation of hydrogen peroxide. CsOxOx is the first bicupin enzyme identified that catalyzes this reaction. The MIMS method of measuring OxOx activity involves continuous, real-time direct detection of oxygen consumption and carbon dioxide production from the ion currents of their respective mass peaks. (13)C2-oxalate was used to allow for accurate detection of (13)CO2 (m/z 45) despite the presence of adventitious (12)CO2. Steady-state kinetic constants determined by MIMS 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-sulphonic acid). Furthermore, we used MIMS to determine that NO inhibits the activity of the CsOxOx with a KI of 0.58±0.06 μM. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Surface activation of MnNb{sub 2}O{sub 6} nanosheets by oxalic acid for enhanced photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Wu, Junshu; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Li, Hongyi; Li, Yongli; Du, Yucheng; Yang, Yilong; Jia, Xinjian

2017-05-01

Graphical abstract: Visible light driven photoreduction of Cr(VI) over MnNb{sub 2}O{sub 6} nanosheets is enhanced via oxalic acid surface complex to generate activation layer. - Highlights: • MnNb{sub 2}O{sub 6} nanosheets are crystallized by a surface capping route of sulfonate groups. • Oxalic acid on MnNb{sub 2}O{sub 6} nanosheets forms an excited surface complex hybrid layer. • Surface activation enhances visible-light induced reduction of Cr(VI) into Cr(III). - Abstract: MnNb{sub 2}O{sub 6} nanosheets (P-MNOs) is selectively crystallized by using surface capping ligand with functional sulfonate group (sodium dodecyl benzene sulphonate), which binds to the (131) surface of MnNb{sub 2}O{sub 6} inducing the morphology-controlled crystallization of MnNb{sub 2}O{sub 6} materials. Surface modification of photoactive P-MNOs with electron-rich oxalic acid ligands establishes an excited surface complex layer on phase-pure P-MNO as evidenced by spectroscopic analyses (FT-IR, UV–vis, Raman, PL, etc.), and thus more efficiently photocatalyzes the reduction of Cr(VI) into Cr(III) than solely P-MNOs or oxalic acid under visible light (λ > 420 nm) via a ligand-to-metal interfacial electron transfer pathway. However, the interaction between oxalic acid and MnNb{sub 2}O{sub 6} is highly dependent upon the morphology of solid MnNb{sub 2}O{sub 6} substrate due to the higher surface-area-to-volume ratio and higher surface activity of (131) planes in the sheet-like morphology. This study could assist the construction of stable niobate material systems to allow a versatile solid surface activation for establishing more energy efficient and robust catalysis process under visible light.

Synthesis and characterization of LiFePO{sub 4} cathode preparation by low temperature method

Energy Technology Data Exchange (ETDEWEB)

Rajesh, Desapogu, E-mail: rajesh.desapogu@gmail.com; Srinivas Naik, V.; Sunandana, C.S., E-mail: sunandana@gmail.com

2015-05-01

We review in detail the physics and technology of the novel material LiFePO{sub 4}, a potential cathode material for Li-ion batteries. In the present work, nano crystalline LiFePO{sub 4} film has been synthesized in both powder and thin film forms from a non-aqueous sol–gel synthesis route based on oxalates of Li and Fe (II). Ferrous oxalate has been synthesized indigenously using a ferrous sulphate based chemical reaction and characterized. Nano powders and thin films of LiFePO{sub 4} have been fabricated and coated on stainless steel substrates with the aim of device development in future. The material has been characterized extensively by XRD for crystal structure, FESEM for microstructure, EDS for elemental analysis and FTIR for the internal modes of phosphate ion. Fe{sup 3+} impurity characterization has been done by using ESR.

Calcium oxalate crystals: an integral component of the Sclerotinia sclerotiorum/Brassica carinata pathosystem.

Directory of Open Access Journals (Sweden)

Margaret B Uloth

Full Text Available 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 (< 0.5 μm to large (up to 40 μm highly organized arrangements. 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.

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Kinetics and mechanism of the oxidation of formic and oxalic acids ...

Indian Academy of Sciences (India)

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 ...

Binding abilities of copper to phospholipids and transport of oxalate

Czech Academy of Sciences Publication Activity Database

Jaklová Dytrtová, Jana; Jakl, M.; Nováková, Kateřina; Navrátil, Tomáš; Šádek, Vojtěch

2015-01-01

Roč. 146, č. 5 (2015), s. 831-837 ISSN 0026-9247 R&D Projects: GA ČR GP13-21409P; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : copper cations * dipalmitoylphosphatidylcholine (lecithin) * ESI-MS * impedance spectroscopy * oxalic acid * voltammetry * membrane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.131, year: 2015

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....

A review of plutonium oxalate decomposition reactions and effects of decomposition temperature on the surface area of the plutonium dioxide product

Energy Technology Data Exchange (ETDEWEB)

Orr, R.M.; Sims, H.E.; Taylor, R.J., E-mail: robin.j.taylor@nnl.co.uk

2015-10-15

Plutonium (IV) and (III) ions in nitric acid solution readily form insoluble precipitates with oxalic acid. The plutonium oxalates are then easily thermally decomposed to form plutonium dioxide powder. This simple process forms the basis of current industrial conversion or ‘finishing’ processes that are used in commercial scale reprocessing plants. It is also widely used in analytical or laboratory scale operations and for waste residues treatment. However, the mechanisms of the thermal decompositions in both air and inert atmospheres have been the subject of various studies over several decades. The nature of intermediate phases is of fundamental interest whilst understanding the evolution of gases at different temperatures is relevant to process control. The thermal decomposition is also used to control a number of powder properties of the PuO{sub 2} product that are important to either long term storage or mixed oxide fuel manufacturing. These properties are the surface area, residual carbon impurities and adsorbed volatile species whereas the morphology and particle size distribution are functions of the precipitation process. Available data and experience regarding the thermal and radiation-induced decompositions of plutonium oxalate to oxide are reviewed. The mechanisms of the thermal decompositions are considered with a particular focus on the likely redox chemistry involved. Also, whilst it is well known that the surface area is dependent on calcination temperature, there is a wide variation in the published data and so new correlations have been derived. Better understanding of plutonium (III) and (IV) oxalate decompositions will assist the development of more proliferation resistant actinide co-conversion processes that are needed for advanced reprocessing in future closed nuclear fuel cycles. - Highlights: • Critical review of plutonium oxalate decomposition reactions. • New analysis of relationship between SSA and calcination temperature. �

United States - Japan Workshop on Dielectric and Piezoelectric Ceramics (3rd) Held in Toyama, Japan on November 9-12, 1986.

Science.gov (United States)

1987-07-30

hydrothermal synthesis method, the oxalate method and the calcination -, method, and among various additives for low firing temperature. As a result. it was...were used as samples: 1) Powder produced by the hydrothermal synthesis method 2) Commercially available powder produced by the oxalate method 3) Powder...4Hii prepared by, coprecipitation in a mixed solution of TIC!- BaCI., and oxalic acid was -alcined at 800 C for I Hr in air. Caicinei BaTilO

Calcium oxalate druses affect leaf optical properties in selenium-treated Fagopyrum tataricum.

Science.gov (United States)

Golob, Aleksandra; Stibilj, Vekoslava; Nečemer, Marijan; Kump, Peter; Kreft, Ivan; Hočevar, Anja; Gaberščik, Alenka; Germ, Mateja

2018-03-01

Plants of the genus Fagopyrum contain high levels of crystalline calcium oxalate (CaOx) deposits, or druses, that can affect the leaf optical properties. As selenium has been shown to modify the uptake and accumulation of metabolically important elements such as calcium, we hypothesised that the numbers of druses can be altered by selenium treatment, and this would affect the leaf optical properties. Tartary buckwheat (Fagopyrum tataricum Gaertn.) was grown outdoors in an experimental field. At the beginning of flowering, plants were foliarly sprayed with sodium selenate solution at 10 mg selenium L -1 or only with water. Plant morphological, biochemical, physiological and optical properties were examined, along with leaf elemental composition and content. Se spraying did not affect leaf biochemical and functional properties. However, it increased leaf thickness and the contents of Se in the leaves, and decreased the density of calcium oxalate druses in the leaves. Except Se content, Se spraying did not affect contents of other elements in leaves, including total calcium per dry mass of leaf tissue. Redundancy analysis showed that of all parameters tested, only the calcium oxalate druses parameters were significant in explaining the variability of the leaf reflectance and transmittance spectra. The density of CaOx druses positively correlated with the reflectance in the blue, green, yellow and UV-B regions of the spectrum, while the area of CaOx druses per mm 2 of leaf transection area positively correlated with the transmittance in the green and yellow regions of the spectrum. Copyright © 2018 Elsevier B.V. All rights reserved.

Solvothermal synthesis of Zn1−xMnxO nanoparticles using oxalate precursor route: Optical and magnetic properties

Directory of Open Access Journals (Sweden)

Tokeer Ahmad

2017-05-01

Full Text Available Nanoparticles of Zn1−xMnxO (x = 0.022, 0.061 and 0.098 were synthesized by a modified solvothermal method through the oxalate precursor route. The precursors were characterized by TG/DTA analysis. Their kinetics has also been studied using the Freeman and Carroll method. The prepared oxide nanoparticles were investigated by powder X-ray diffraction (PXRD, transmission electron microscopy (TEM, optical and BET surface area studies. PXRD patterns were matched with hexagonal ZnO structure, however few impurity peaks of ZnMnO3 appeared. Reflectance measurements showed that Mn2+ is incorporated in the Zn matrix. The band gap decreases on increasing Mn concentration. The particle size decreases from 18 to 9 nm and the surface area increases (255.4–582.9 m2g−1 on increasing Mn concentration. All these solid solutions show paramagnetic behaviour with very weak antiferromagnetic interactions. The effective magnetic moment of these nanoparticles comes out to be 4.91, 4.77 and 4.18 μB/Mn2+.

The promotion effect of coexisting hygroscopic composition on the reaction between oxalic acid and calcite during humidifying process

Science.gov (United States)

Ma, Q.; He, H.

2012-12-01

Internally mixed oxalic acid with mineral dust has been frequently detected in field measurements (Sullivan and Prather, 2007; Wang et al., 2012; Yang et al., 2009). Meanwhile, Furukawa and Takahashi (Furukawa and Takahashi, 2011) found that most of the oxalic acid in mineral mixture is present as metal oxalate complexes in the aerosols, however, the formation mechanism of these complexes is not well known. It was reported that cloud process of H2C2O4/CaCO3 mixture could lead to the formation of calcium oxalate (Gierlus et al., 2012). Recently, we used Raman spectroscopy to investigate the hygroscopic behavior of H2C2O4/CaCO3 mixture below saturation condition as well as the effect of coexisting hygroscopic compositions, e.g. Ca(NO3)2, NaCl, NH4NO3, and (NH4)2SO4. It was found that there was no interaction between H2C2O4 and calcite without third component during humidifying process under ambient condition. In contrast, the presence of coexisting Ca(NO)3, NaCl, or NH4NO3 could promote the reaction between H2C2O4 and calcite by providing an aqueous circumstance after deliquescence, resulting in the formation of calcium oxalate hydrates. Moreover, substitution of strong acid (HNO3) by medium acid (H2C2O4) occurred when water vapor was absorbed in Ca(NO3)2/H2C2O4 mixture (Ma and He, 2012). As for (NH4)2SO4, there existed a competition effect between (NH4)2SO4 and H2C2O4 for the reaction with CaCO3. CaCO3 was preferentially reacted with (NH4)2SO4 to form gypsum in the solution, while the residual NH4+ and C2O42- ions were bonded to (NH4)2C2O4 after efflorescence. These results implies a potential formation pathway of metal oxalate complexes in the atmosphere and also suggests that synergistic effect between different constituents in humidifying process of mixed particles should be considered in future hygroscopic behavior studies.

Sol – Gel synthesis and characterization of magnesium peroxide nanoparticles

International Nuclear Information System (INIS)

Jaison, J; Chan, Y S; Ashok raja, C; Balakumar, S

2015-01-01

Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO 2 ) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO 2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles. (paper)

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.

Synthesis and configurational analysis of phosphonate cavitands

NARCIS (Netherlands)

Jacopozzi, Paola; Dalcanale, Enrico; Spera, Silvia; Chrisstoffels, L.A.J.; Reinhoudt, David; Lippmann, Tino; Mann, Gerhard

1998-01-01

Synthesis, separation and configurational analysis of phosphonated and partially phosphonated cavitands derived from resorcinarenes are described. The configuration of all diastereomers has been elucidated by their 1H, 31P NMR spectra and 13C relaxation times. In all cases the course of the bridging

Redox Cycling, pH Dependence, and Ligand Effects of Mn(III) in Oxalate Decarboxylase from Bacillus subtilis.

Science.gov (United States)

Twahir, Umar T; Ozarowski, Andrew; Angerhofer, Alexander

2016-11-29

This contribution describes electron paramagnetic resonance (EPR) experiments on Mn(III) in oxalate decarboxylase of Bacillus subtilis, an interesting enzyme that catalyzes the redox-neutral dissociation of oxalate into formate and carbon dioxide. Chemical redox cycling provides strong evidence that both Mn centers can be oxidized, although the N-terminal Mn(II) appears to have the lower reduction potential and is most likely the carrier of the +3 oxidation state under moderate oxidative conditions, in agreement with the general view that it represents the active site. Significantly, Mn(III) was observed in untreated OxDC in succinate and acetate buffers, while it could not be directly observed in citrate buffer. Quantitative analysis showed that up to 16% of the EPR-visible Mn is in the +3 oxidation state at low pH in the presence of succinate buffer. The fine structure and hyperfine structure parameters of Mn(III) are affected by small carboxylate ligands that can enter the active site and have been recorded for formate, acetate, and succinate. The results from a previous report [Zhu, W., et al. (2016) Biochemistry 55, 429-434] could therefore be reinterpreted as evidence of formate-bound Mn(III) after the enzyme is allowed to turn over oxalate. The pH dependence of the Mn(III) EPR signal compares very well with that of enzymatic activity, providing strong evidence that the catalytic reaction of oxalate decarboxylase is driven by Mn(III), which is generated in the presence of dioxygen.

2,4-Diamino-6-methyl-1,3,5-triazin-1-ium hydrogen oxalate

Directory of Open Access Journals (Sweden)

Bohari M. Yamin

2012-05-01

Full Text Available The title compound, C4H8N5+·C2HO4−, was obtained from the reaction of oxalic acid and 2,4-diamino-6-methyl-1,3,5-triazine. The protonated triazine ring is essentially planar with a maximum deviation of 0.035 (1 Å, but the hydrogen oxalate anion is less planar, with a maximum deviation of 0.131 (1 Å for both carbonyl O atoms. In the crystal, the ions are linked by intermolecular N—H...O, N—H...N, O—H...O and C—H...O hydrogen bonds, forming a three-dimensional network. Weak π–π [centroid–centroid distance = 3.763 Å] and C—O...π interactions [O...centroid = 3.5300 (16 Å, C—O...centroid = 132.19 (10°] are also present.

Development and characterization of oxalate coatings for the corrosion protection of metallic zinc

International Nuclear Information System (INIS)

Oliveira, M.; Ferreira Junior, J.M.; Baker, M.A.; Rossi, J.; Costa, I.

2016-01-01

This work aims to develop and characterize surface treatments for corrosion protection of zinc. Oxalic acid (OA) was used and the concentration range selected was from 10"-"1 M to 1 M. The chemical composition of the layers formed was evaluated by XPS, and the morphology and thickness, by FIB and EDS, respectively. The corrosion resistance was monitored by Electrochemical Impedance Spectroscopy (EIS). The results showed that a zinc oxalate layer had been formed in both concentrations but of different thickness and crystal sizes but similar morphology. The EIS results showed that the layer formed in the lower concentration solution provided corrosion protection for long periods whereas the one obtained at higher concentration did not protect the surface. The results led to conclude that one of the treatments tested is highly indicated for corrosion protection of zinc. (author)

Bridging the Gap between Social Animal and Unsocial Machine: A Survey of Social Signal Processing

NARCIS (Netherlands)

Vinciarelli, Alessandro; Pantic, Maja; Heylen, Dirk K.J.; Pelachaud, Catherine; Poggi, Isabella; D’Ericco, Francesca; Schröder, Marc

Social Signal Processing is the research domain aimed at bridging the social intelligence gap between humans and machines. This paper is the first survey of the domain that jointly considers its three major aspects, namely, modeling, analysis, and synthesis of social behavior. Modeling investigates

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

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.

Dilute oxalic acid pretreatment for biorefining giant reed (Arundo donax L.)

Science.gov (United States)

Danilo Scordia; Salvatore L. Cosentino; Jae-Won Lee; Thomas W. Jeffries

2011-01-01

Biomass pretreatment is essential to overcome recalcitrance of lignocellulose for ethanol production. In the present study we pretreated giant reed (Arundo donax L.), a perennial, rhizomatous lignocellulosic grass with dilute oxalic acid. The effects of temperature (170-190 ºC), acid loading (2-10% w/w) and reaction time (15-40 min) were handled as a single...

Synthesis and structural characterization of a calcium coordination ...

Indian Academy of Sciences (India)

Synthesis and structural characterization of a calcium coordination polymer based on a μ3-bridging. tetradentate binding mode of glycine. SUBRAMANIAN NATARAJAN*a, BIKSHANDARKOIL R. SRINIVASANb , J. KALYANA SUNDARa, K. RAVIKUMARc , R.V. KRISHNAKUMARd , J. SURESHe,. aSchool of Physics, ...

Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

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

Isotopic fractionation of NBS oxalic acid and its influence in the calculated age of materials

International Nuclear Information System (INIS)

Nehmi, V.A.

1979-10-01

The intensity of the isotopic fractionation during the oxidation of NBS oxalic acid to carbon dioxide was checked. 30 reactions of oxidation of NBS oxalic acid with potassium permanganate were made. The resultant isotopic composition of CO 2 has been determined with a mass-spectrometer. A conclusion has been reached that the average of Δ 13 C is - 18.9% o with variation between - 17.7 and - 21.2%o. For values of Δ 13 C equal to - 22.0%o, the calculated age with isotopic correction shows the following deviations in relation to non-corrected age: 4% for materials of 1,000 years and 0.3% for 20,000 years.(Author) [pt

Effects of Orthosiphon grandiflorus, Hibiscus sabdariffa and Phyllanthus amarus extracts on risk factors for urinary calcium oxalate stones in rats.

Science.gov (United States)

Woottisin, Surachet; Hossain, Rayhan Zubair; Yachantha, Chatchai; Sriboonlue, Pote; Ogawa, Yoshihide; Saito, Seiichi

2011-01-01

We evaluated the antilithic effect of Orthosiphon grandiflorus, Hibiscus sabdariffa and Phyllanthus amarus extracts on known risk factors for calcium oxalate stones in rats. We divided 30 male Wistar rats into 5 equal groups. Controls were fed a standard diet and the remaining groups received a 3% glycolate diet for 4 weeks to induce hyperoxaluria. One glycolate fed group served as the untreated group and the others were given oral extracts of Orthosiphon grandiflorus, Hibiscus sabdariffa or Phyllanthus amarus at a dose of 3.5 mg daily. We collected 24-hour urine and blood samples. Kidneys were harvested for histological examination. We measured the renal tissue content of calcium and oxalate. The Hibiscus sabdariffa group showed significantly decreased serum oxalate and glycolate, and higher oxalate urinary excretion. The Phyllanthus amarus group showed significantly increased urinary citrate vs the untreated group. Histological examination revealed less CaOx crystal deposition in the kidneys of Hibiscus sabdariffa and Phyllanthus amarus treated rats than in untreated rats. Those rats also had significantly lower renal tissue calcium content than untreated rats. All parameters in the Orthosiphon grandiflorus treated group were comparable to those in the untreated group. Hibiscus sabdariffa and Phyllanthus amarus decreased calcium crystal deposition in the kidneys. The antilithic effect of Hibiscus sabdariffa may be related to decreased oxalate retention in the kidney and more excretion into urine while that of Phyllanthus amarus may depend on increased urinary citrate. In contrast, administering Orthosiphon grandiflorus had no antilithic effect. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A non-acid-assisted and non-hydroxyl-radical-related catalytic ozonation with ceria supported copper oxide in efficient oxalate degradation in water

KAUST Repository

Zhang, Tao

2012-06-01

Oxalate is usually used as a refractory model compound that cannot be effectively removed by ozone and hydroxyl radical oxidation in water. In this study, we found that ceria supported CuO significantly improved oxalate degradation in reaction with ozone. The optimum CuO loading amount was 12%. The molar ratio of oxalate removed/ozone consumption reached 0.84. The catalytic ozonation was most effective in a neutral pH range (6.7-7.9) and became ineffective when the water solution was acidic or alkaline. Moreover, bicarbonate, a ubiquitous hydroxyl radical scavenger in natural waters, significantly improved the catalytic degradation of oxalate. Therefore, the degradation relies on neither hydroxyl radical oxidation nor acid assistance, two pathways usually proposed for catalytic ozonation. These special characters of the catalyst make it suitable to be potentially used for practical degradation of refractory hydrophilic organic matter and compounds in water and wastewater. With in situ characterization, the new surface Cu(II) formed from ozone oxidation of the trace Cu(I) of the catalyst was found to be an active site in coordination with oxalate forming multi-dentate surface complex. It is proposed that the complex can be further oxidized by molecular ozone and then decomposes through intra-molecular electron transfer. The ceria support enhanced the activity of the surface Cu(I)/Cu(II) in this process. © 2012 Elsevier B.V.

Railroad Bridges

Data.gov (United States)

Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

The study of the inhibitory effect of calcium oxalate monohydrate's crystallization by two medicinal and aromatic plants: Ammi visnaga and Punica granatum.

Science.gov (United States)

Kachkoul, R; Sqalli Houssaini, T; Miyah, Y; Mohim, M; El Habbani, R; Lahrichi, A

2018-03-01

Urinary lithiasis is a recurrent disease defined by the presence of calculi in the urinary tract. Most urinary calculi have as a major component calcium oxalate which occurs mainly in two crystalline forms: Calcium oxalate monohydrate (whewellite) and calcium oxalate dihydrate (weddellite). The target behind, this work is to study the inhibiting effect of the calcium oxalate's crystallization by the extract of the Ammi visnaga and the Punica granatum. The inhibition of crystallization has been studied in vitro with both the absence and the presence of the different concentrations of the extracts of the two plants. This study consists in measurement, with the UV-Visible spectrophotometer, the temporal evolution of the optical density at λ equal to 620nm corresponding to the formation of the crystals due to the mixing of metastable solutions of calcium and oxalate. The characterization of the crystals is carried out in parallel by both the Fourier transform infrared spectra (FT-IR) and the observation of the crystals with the help of an optical microscope. In this respect, the inhibition percentages were calculated from the turbidity slopes in the presence and absence of the extract. The results obtained were more effective, especially for Punica granatum with percentages of 97.8±0.12 and 83.46±1.34% against nucleation and aggregation, respectively, the order of Ammi visnaga was as follow: 73.25±0.81 and 59.44±3.3%. Thus, all correlation coefficients are greater than 0.95 and all coefficients of variation are less than 10%. The prevention and treatment of urinary lithiasis and especially in the case of recurrence by plants remains an alternative choice for medical methods. This study justified the efficacy of the plants Ammi visnaga and in particular Punica granatum against the crystallization of calcium oxalate. 3. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

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.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

Reactivity of uranium(IV) bridged chalcogenido complexes UIV–E–UIV (E = S, Se) with elemental sulfur and selenium: synthesis of polychalcogenido-bridged uranium complexes

OpenAIRE

Franke, Sebastian M.; Heinemann, Frank W.; Meyer, Karsten

2014-01-01

We report the syntheses, electronic properties, and molecular structures of a series of polychalcogenido-bridged dinuclear uranium species. These complexes are supported by the sterically encumbering but highly flexible, single N-anchored tris(aryloxide) chelator (AdArO)3N3−. Reaction of an appropriate uranium precursor, either the U(III) starting material, [((AdArO)3N)U(DME)], or the dinuclear mono-chalcogenido-bridged uranium(IV/IV) compounds [{((AdArO)3N)U(DME)}2(μ-E)] (E = S, Se), with el...

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Indian Academy of Sciences (India)

Several media, it has been found that a saturated solution of starch and water could be employed to obtain acicular crystals. 2.3 Synthesis of mixed oxalates. The starting materials for the Synthesis of doped gamma ferric oxide were mixed oxalates of iron and the dopant (Mg/Co/Ni/Cu), which was co-precipitated from a.

Structural stability of (Pu1-xAmx)O2 (x=0.2;0.5;0.8) obtained by oxalate co-conversion

International Nuclear Information System (INIS)

Jankowiak, A.; Donnet, L.; Maillard, C.

2008-01-01

The EUROTRANS project investigates the transmutation of transuranium elements in dedicated reactors (ADS, FR). The study includes various subject areas: neutronics, physical properties, coolant type (sodium, lead, bismuth, helium), etc, and experimental work concerning the fabrication of minor actinide compounds for thermo-physical properties determination. For this program, the CEA was responsible for synthesizing three Pu 1-x Am x O 2 compounds with various Am and Pu content (x = 0.2, 0.5, 0.8). The selected synthesis route for the mixed Am and Pu oxide powder consists in actinides oxalates co-conversion. The purpose of the study was to determine by XRD the crystal structure and the lattice parameters change as a function of the time for each co-converted mixed oxides. After one year of experiment, although the lattice parameters significantly expanded, the compounds remained monophasic. The observations showed that the initial expansion rate and the a max stage value vary according to the Pu and Am content. (authors)

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

Copper tolerance of brown-rot fungi : time course of oxalic acid production

Science.gov (United States)

Frederick Green; Carol A. Clausen

2003-01-01

The increase in the use of non-arsenical copper-based wood preservatives in response to environmental concerns has been accompanied by interest in copper-tolerant decay fungi. Oxalic acid production by brown-rot fungi has been proposed as one mechanism of copper tolerance. Fifteen brown-rot fungi representing the genera Postia, Wolfiporia, Meruliporia, Gloeophyllum,...

Synthesis and X-ray diffraction study of new uranyl malonate and oxalate complexes with carbamide

Energy Technology Data Exchange (ETDEWEB)

Medvedkov, Ya. A.; Serezhkina, L. B., E-mail: Lserezh@samsu.ru [Samara State University (Russian Federation); Grigor’ev, M. S. [Russian Academy of Sciences, Frumkin Institute of Physical Chemistry and Electrochemistry (Russian Federation); Serezhkin, V. N. [Samara State University (Russian Federation)

2016-05-15

Two new malonate-containing uranyl complexes with carbamide of the formulas [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Urea){sub 2}] (I) and [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Urea){sub 3}] (II), where Urea is carbamide, and one uranyl oxalate complex of the formula [UO{sub 2}(C{sub 2}O{sub 4})(Urea){sub 3}] (III) were synthesized, and their crystals were studied by X-ray diffraction. The main structural units in crystals I are the electroneutral chains [UO{sub 2}(C{sub 3}H{sub 2}O{sub 4})(Urea){sub 2}]{sub ∞} belonging to the crystal-chemical group AT{sup 11}M{sub 2}{sup 1} (A = UO{sub 2}{sup 2+}, T{sup 11} = C{sub 3}H{sub 2}O{sub 4}{sup 2-}, M{sup 1} = Urea) of uranyl complexes. Crystals II and III are composed of the molecular complexes [UO{sub 2}(L)(Urea){sub 3}], where L = C{sub 3}H{sub 2}O{sub 4}{sup 2-} or C{sub 2}O{sub 4}{sup 2-}, belonging to the crystal-chemical group AB{sup 01}M{sub 3}{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = C{sub 3}H{sub 2}O{sub 4}{sup 2-} or C{sub 2}O{sub 4}{sup 2-}, M{sup 1} = Urea). The characteristic features of the packing of the uranium-containing complexes are discussed in terms of molecular Voronoi–Dirichlet polyhedra. The effect of the Urea: U ratio on the structure of uranium-containing structural units is considered.

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

Process development of oxalic acid production in submerged culture of Aspergillus niger F22 and its biocontrol efficacy against the root-knot nematode Meloidogyne incognita.

Science.gov (United States)

Lee, Sang Il; Lee, Keon Jin; Chun, Ho Hyun; Ha, Sanghyun; Gwak, Hyun Jung; Kim, Ho Myeong; Lee, Jong-Hee; Choi, Hak-Jong; Kim, Hyeong Hwan; Shin, Teak Soo; Park, Hae Woong; Kim, Jin-Cheol

2018-03-01

Oxalic acid has potent nematicidal activity against the root-knot nematode Meloidogyne incognita. In this study, fermentation parameters for oxalic acid production in submerged culture of Aspergillus niger F22 at 23, 25, and 30 °C were optimized in 5-L jar fermenters. The viscosity of the culture broth increased with increasing temperature. There was a negative correlation between oxalic acid production and the apparent viscosity; high volumetric productivity of oxalic acid was obtained at low apparent viscosity (less than 1000 cP), with a productivity of more than 100 mg/L h. When the apparent viscosity was over 2500 cP, the volumetric productivity decreased below 50 mg/L h. In addition, the volumetric mass transfer coefficient, K L a, positively correlated with volumetric productivity. When the K L a value increased from 0.0 to 0.017 /s, the volumetric productivity proportionally increased up to 176 mg/L h. When the temperature decreased, K L a increased due to the decrease in viscosity, leading to increased volumetric productivity. The highest productivity of 7453.3 mg/L was obtained at the lowest temperature, i.e., 23 °C. The nematicidal activity of culture filtrate was proportional to the content of oxalic acid. Based on a constant impeller tip speed, oxalic acid production was successfully scaled up to a 500-L pilot vessel, producing a final concentration comparable to that in the 5-L jar.

Adventures in bridgehead substitution chemistry: synthesis of polycyclic polyprenylated acylphloroglucinols (PPAPs).

Science.gov (United States)

Simpkins, Nigel S

2013-02-04

The polycyclic polyprenylated acylphloroglucinol (PPAP) family of natural products includes important compounds with notable biological activities, such as garsubellin A, hyperforin and clusianone. The synthesis of these complex, bridged, highly oxidized and substituted systems presents a formidable challenge to synthetic chemists. This feature article describes how the use of unconventional bridgehead substitution chemistry has enabled the synthesis of these natural products and their analogues.

Mechanism and kinetics of thermal decomposition of ammoniacal complex of copper oxalate

International Nuclear Information System (INIS)

Prasad, R.

2003-01-01

A complex precursor has been synthesized by dissolving copper oxalate in liquor ammonia followed by drying. The thermal decomposition of the precursor has been studied in different atmospheres, air/nitrogen. The mechanism of decomposition of the precursor in air is not as simple one as in nitrogen. In nitrogen, it involves endothermic deammoniation followed by decomposition to finely divided elemental particles of copper. Whereas in air, decomposition and simultaneous oxidation of the residual products (oxidative decomposition), make the process complex and relatively bigger particle of cupric oxide are obtained as final product. The products of decomposition in different atmospheres have been characterized by X-ray diffraction and particle size analysis. The stoichiometric formula, Cu(NH 3 ) 2 C 2 O 4 of the precursor is established from elemental analysis and TG measurements, and it is designated as copper amino oxalate (CAO). In nitrogen atmosphere, the deammoniation and decomposition have been found to be zero and first order, respectively. The values of activation energy have been found to be 102.52 and 95.38 kJ/mol for deammoniation and decomposition, respectively