نتایج جستجو برای: borate

تعداد نتایج: 3395  

2000
Richard E. Zeebe Abhijit Sanyal Joseph D. Ortiz Dieter A. Wolf-Gladrow

Ž Ž . . Ž Ž .y. Dissolved boron in seawater occurs mainly in the form of boric acid B OH and borate B OH . While the 3 4 equilibrium properties of the dissociation of boric acid have been studied in detail, very little work has focused on the kinetics of the boric acid–borate equilibrium in seawater. Here, we present a theoretical study of the relaxation of the w Ž . seawater borate–carbonate s...

Journal: :The Journal of Experimental Medicine 1944
C. A. Knight

The stability of centrifugally purified PR8 influenza virus at pH 7 in 0.001, 0.01, 0.1, and 1.0 M phosphate buffers, in veronal and borate buffers, and in adjusted solutions of saline and distilled water was investigated. The results demonstrate that the stability of this virus can vary considerably at pH 7 depending upon the nature and concentration of the salts present. Borate, veronal, and ...

2003
BORGHILD TVEIT GERD SVENNEBY

A method for preparing highly purified glutaminase (EC 3.5.1.2, L-glutamine amidohydrolase) from pig renal cortex is described. The main steps consist of sodium sulfate fractionation followed by alternative solubilization by dialysis against Tris-HCI buffer and precipitation with phosphateborate. The linal enzyme preparation contains no impurities which could be detected by sucrose gradient cen...

Journal: :Environmental Health Perspectives 1994
H R Massie

Total boron concentrations in Drosophila changed during development and aging. The highest concentration of boron was found during the egg stage, followed by a decline during the larval stages. Newly emerged flies contained 35.5 ppm boron. During the adult stage the boron concentration increased by 52% by 9 weeks of age. Adding excess dietary boron during the adult stage decreased the median li...

Journal: :Organic & biomolecular chemistry 2011
Xavier Garrabou Jordi Calveras Jesús Joglar Teodor Parella Jordi Bujons Pere Clapés

Aldol addition reactions of dihydroxyacetone (DHA) to N-Cbz-amino aldehydes catalyzed by L-rhamnulose-1-phosphate aldolase (RhuA) in the presence of borate buffer are reported. High yields of aldol adduct (e.g. 70-90%) were achieved with excellent (>98 : 2 syn/anti) stereoselectivity for most S or R configured acceptors, which compares favorably to the reactions performed with DHAP. The stereoc...

Journal: :Journal of bacteriology 1983
L M Kozloff M A Schofield M Lute

Chemical and biological properties of the ice nucleating sites of Pseudomonas syringae, strain C-9, and Erwinia herbicola have been characterized. The ice nucleating activity (INA) for both bacteria was unchanged in buffers ranging from pH 5.0 to 9.2, suggesting that there were no essential groups for which a change in charge in this range was critical. The INA of both bacteria was also unaffec...

Journal: :Organic & biomolecular chemistry 2013
Michael E Deary Marcus C Durrant D Martin Davies

Our recent work has provided new insights into the equilibria and species that exist in aqueous solution at different pHs for the boric acid - hydrogen peroxide system, and the role of these species in oxidation reactions. Most recently, (M. C. Durrant, D. M. Davies and M. E. Deary, Org. Biomol. Chem., 2011, 9, 7249-7254), we have produced strong theoretical and experimental evidence for the ex...

Journal: :Acta Crystallographica Section E Structure Reports Online 2010

2011
Edward S. Grew Jeffrey L. Bada Robert M. Hazen

The RNA World is generally thought to have been an important link between purely prebiotic (>3.7 Ga) chemistry and modern DNA/protein biochemistry. One concern about the RNAWorld hypothesis is the geochemical stability of ribose, the sugar moiety of RNA. Prebiotic stabilization of ribose by solutions associated with borate minerals, notably colemanite, ulexite, and kernite, has been proposed as...

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