The heterogeneous reaction of OH radicals with sub-micron unsaturated fatty acid particles in the presence of H2O2 and O2 is studied to explore how surface OH addition reactions initiate chain reactions that rapidly transform the chemical composition of an organic particle. In the presence of 20.7 ppm [H2O2] in a 10% mixture of O2 in N2, the effective uptake coefficients of oleic acid, linoleic...

CYP24A1 is a mitochondrial cytochrome P450 (CYP) that catabolizes 1α,25-dihydroxyvitamin D(3) (1α,25-(OH)(2)D(3)) to different products: calcitroic acid or 1α,25-(OH)(2)D(3)-26,23-lactone via multistep pathways commencing with C24 and C23 hydroxylation, respectively. Despite the ability of CYP24A1 to catabolize a wide range of 25-hydroxylated analogs including 25-hydroxyvitamin D(3), the enzyme...

Hydroxyl radical (˙OH) scavenging reaction rate constants of standard natural organic matter (NOM) isolates (k˙OH,NOM) were measured with a rapid background scavenging method, to expand the dataset of published k˙OH,NOM values. The proposed method relies on ˙OH generation with a simple UV/H₂O₂ AOP-based system. The associated decay of a ˙OH probe compound is monitored with a field-deployable sp...

the kinetics of the de complexation by hydroxyl ions of some pervanadyl, molybdate and tungstate amionocarboxylate complexes have been studied spectrophotometrically by means of a stopped flow technique. the chelate groups used were the iminodiacetic acid (ida), ethylenediarnine-n,n' -diacetic acid (edda), nitrilotriacetic acid (nta) and ethylene diamine-n,n,n' ,n'-tetraacetic ac...

Transactivation of the rat apical sodium-dependent bile acid transporter (ASBT; Slc10a2) by 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] via the vitamin D receptor (VDR), was studied. Levels of ASBT protein and mRNA were low in the duodenum and high in the ileum, and both were induced by 1,25(OH)(2)D(3). The nuclear receptor protein, VDR, was present uniformly in the duodenum, jejunum, and...

The biodegradation of iron-citrate complexes depends on the structure of the complex formed between the metal and citric acid. Ferric iron formed a bidentate complex with citric acid, [Fe(III) (OH)(2) cit] involving two carboxylic acid groups, and was degraded at the rate of 86 muM h. In contrast, ferrous iron formed a tridentate complex with citric acid, [Fe(II) cit], involving two carboxylic ...

DFT calculations were carried out to investigate reaction paths of L-ascorbic acid (AAH2), hydroxyl radicals and water clusters. Frontier-orbital analyses were also performed to examine the regioselectivity of the OH˙ addition. Transition states of the electrolytic dissociation of AAH2 and intermediate carboxylic acids were found to have very small activation energies through proton transfers a...

The hydroxyl radical (OH•) is a powerful oxidant produced as a consequence of cavitation in water. It can react nonspecifically in breaking down persistent organic pollutants in water into their mineral form. It can also recombine to form hydrogen peroxide which is very useful in water treatment. In this study, terephthalic acid (TA) and potassium iodide dosimetry were used to quantify and inve...

via Infrared Action Spectroscopy Ilana B. Pollack, Ian M. Konen, Eunice X.J. Li, and Marsha I. Lester Department of Chemistry, University of Pennsylvania Philadelphia, PA 19104-6323 Abstract The trans-perp (tp) conformer of peroxynitrous acid (HOONO), a secondary product of the OH + NO2 reaction and a less stable isomer of nitric acid, has been identified by infrared action spectroscopy in the ...

N-Protected derivatives of 1-amino-cyclo-hexa-neacetic acid (β(3,3)-Ac6c), namely Valeroyl-β(3,3)-Ac6c-OH [2-(1-pentanamidocyclohexyl)acetic acid, C13H23NO3], (I), Fmoc-β(3,3)-Ac6c-OH [2-(1-{[(9H-fluoren-9-yloxy)carbonyl]amino}cyclohexyl)acetic acid, C23H25NO4], (II), and Pyr-β(3,3)-Ac6c-OH {2-[1-(pyrazine-2-amido)cyclohexyl]acetic acid, C13H17N3O3}, (III), were synthesized and their conformati...