The influence of cathodic pretreatment on the kinetics of hydroxide ion oxidation on polycrystalline gold electrode

The electrochemical oxidation of the hydroxide ion was studied on a gold rotating disc electrode (RDE), in aqueous NaOH solutions in the presence of lithium perchlorate as a supporting electrolyte. By potentiodynamic polarization within the limits −1.6 V and +1.6 V vs. SCE, it was demonstrated that the overvoltage of the OH⁻ ion oxidation reaction may be significantly reduced with a 5 min long delay at the vertex cathodic potential of −1.6 V. This finding was explained in terms of the type of gold oxide formed on the gold surface under different experimental conditions.     

Rapid determination of urinary globotriaosylceramide isoform profiles by electrospray ionization mass spectrometry using stearoyl-d35-globotriaosylceramide as internal standard

Globotriaosylceramide is a neutral glycolipid containing the trihexoside Gal(alpha1-4)Gal(ss1-4)Glc(ss1-1') covalently bound to N-acylsphingosine. It was identified as the main storage substance in the kidney of patients with Fabry disease, an X-linked deficiency of lysosomal alpha-galactosidase A which can significantly be ameliorated by enzyme replacement therapy. Unlike hemizygote males, affected heterozygote females cannot be identified by enzyme assays and therefore may remain untreated. A quantitation of urinary globotriaosylceramides was proposed as an alternative method for their diagnosis. However, the required studies on physiological and pathological variations in the excretion of trihexosides so far have been prevented by a lack of suitable methods. A validated, robust and quick high-throughput method for the quantitative analysis of globotriaosylceramide isoforms using stable-isotope-dilution/internal standardization and electrospray ionization mass spectrometry (ESI-MS) was developed. An internal standard, stearoyl-d35-globotriaosylceramide, was synthesized by enzymatic coupling of d35-stearic acid to the corresponding lyso-ceramidetrihexoside. Glycolipid isoforms of high purity were obtained from a 5-mL urine portion by extraction on C18 solid-phase columns and a novel washing protocol. ESI-MS analysis was performed in full and neutral loss scan modes. Urinary trihexosyl- and some of the di- and monohexosylceramide isoforms can be quantified within a single experiment. All glycolipid isoforms were above detection limit in healthy male and female subjects (n = 63). Prominent elevations of tetracosanoyl-(C24:0 plus C24:1)-globotriaosylceramides were found in urines from female (>2.5-fold above normals) or male Fabry patients (>5.8-fold above normals), but not among controls. Globotriaosylceramide isoforms shall now be analyzed in Fabry patients, non-genetic kidney disease and healthy subjects to define the conditions for a safe diagnosis of heterozygotes.     

An atomic mutation cycle for exploring RNA's 2'-hydroxyl group

The 2'-hydroxyl group fulfills numerous structural and functional roles in RNA, including those of hydrogen bond donor and acceptor. While loss of function upon 2'-deoxynucleotide substitution establishes the importance of specific 2'-hydroxyl groups within RNA, this approach provides no information about how these hydroxyl groups impart their functional contribution. We use an atomic mutation cycle to evaluate the functional importance of the 2'-hydroxyl group's hydrogen atom. Using the Tetrahymena ribozyme reaction, we challenge the cycle to expose the catalytic contribution of the cleavage site 2'-hydroxyl group and its associated hydrogen bond network. The results establish the viability of this cycle as an approach to reveal 2'-hydroxyl groups that donate functionally significant hydrogen bonds.     

Electrochemical synthesis and characterization of basic bismuth nitrate [Bi6O5(OH)3](NO3)5·2H2O: a potential highly efficient sorbent for textile reactive dye removal

Research on Chemical Intermediates - A new method of synthesis was developed for the preparation of basic bismuth nitrate [Bi6O5(OH)3](NO3)5·2H2O (ECBBN). Electrochemical synthesis of the...     

Mass anomalous dimension in SU(2) with six fundamental fermions

We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schrödinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension γ, and find it is between 0.135 and 1.03 in the range of couplings consistent with the existence of an IR fixed point.     

Perturbations of Smooth Actions with Nontrivial Cohomology

We prove a general perturbation result for smooth Lie group actions with nontrivial finite‐dimensional cohomology. It describes sufficient conditions on cohomology over an action which imply that the action lies in a finite‐dimensional family of actions such that any small perturbation of the family intersects the smooth conjugacy class of the given action. We cast the classical KAM result on perturbations of Diophantine vector fields on tori into this general setup, and we address a few applications and potential applications of this result to homogeneous Lie group actions with finite‐dimensional first cohomology. © 2014 Wiley Periodicals, Inc.     

Influence of antimicrobial finishes on the biodeterioration of cotton and cotton/polyester fabrics: Leaching versus bio-barrier formation

The influence of antimicrobial activity of two contemporary finishes, specifically a dispersion of colloidal silver (Ag) and 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC), on the degree of biodeterioration of 100% cotton (CO) fabric and fabric composed of a mixture of cotton and polyester (CO/PET) was studied. Ag was chosen for the leaching agent, while Si-QAC was used as the bio-barrier-forming agent. The biodeterioration of samples finished with different concentrations of Ag and Si-QAC was analysed from a standard soil burial test after 3, 6 and 12 days of exposure to soil microflora. SEM micrographs revealed intensive biodeterioration of the unfinished cellulose fibres, while the highly biologically resistant polyester fibres remained undamaged. A controlled release of Ag successfully inhibited biodeterioration of the cellulose fibres in the CO and CO/PET fabrics when its concentration reached a lethal, biocidal concentration. Contrary to the effects of Ag, the bio-barrier formation of Si-QAC on CO and CO/PET fabrics was insufficient to protect the cellulose fibres during longer periods of soil burial, irrespective of its concentration. Intensive chemical changes to the cellulose were clearly seen from the FT-IR spectra of all of the samples. The resistance of the polyester component to biodeterioration did not provide any significant protection for the cotton component in CO/PET fabric.     

A Spectrophotometric Study of Streptomycin Effect on the Clinical Urea Determination

The results of studying inhibitory effect of streptomycin on the modified Berthelot reaction were presented in this paper and a new kinetic method for determining streptomycin in pharmaceutical preparations and human urine was developed on the basis of the obtained results. The rates of catalytic and catalytic‐inhibitory reaction were monitored at 700 nm (t=25±0.1°C) using UV/vis spectrophotometer. By analyzing the spectra and experimental dependences of the catalytic and catalytic‐inhibitory reaction rates on the reactant concentrations, it was noticed that streptomycin attacked nitroprusside and hypochlorite causing the inhibition of the production of 2,2′‐dicarboxylindophenol. According to this effect, an analytical decrease for determination of urea by modified Berthelot reaction appeared in the presence of small amounts of streptomycin. Beer's law was obeyed in the interval of streptomycin sulfate concentration from 18.2 to 182 µg·mL^?1. The detection limit calculated by two methods was obtained at 11.75 µg·mL^?1 and 8.54 µg·mL^?1. The relative standard deviation of 0.55%–8.83% and the recovery of 109.10% were determined. The obtained results were validated using the referent HPLC method.