Separation and quantification of the urinary enantiomers of 2-hydroxyglutaric acid by capillary electrophoresis with capacitively coupled contactless conductivity detection: Application to the diagnosis of D- and L-2-hydroxyglutaric aciduria

2-hydroxyglutaric aciduria is an inherited neurometabolic disorder with two major types: D-2-hydroxyglutaric aciduria and L-2-hydroxyglutaric aciduria. An easy and fast capillary electrophoresis system combined with a capacitively coupled contactless conductivity detection method was developed for the enantioseparation and determination of D- and L-2-hydroxyglutaric acid in urine. D- and L-2-hydroxyglutaric acids were separated using vancomycin as the chiral selector. The optimal separation conditions for enantiomers were achieved by the use of a buffer containing 50 mM 4-(N-morpholino) butane sulfonic acid solution (pH 6.5), an electroosmotic flow modifier (0.001% [w/v] polybrene), and 30 mM vancomycin as chiral selector. The analysis time was 6 min under optimal conditions. The optimized and validated method was successfully implemented for quantifying D- and L-2-hydroxyglutaric aciduria in patients’ urine, without any pretreatment step. The linearity of the method was determined to be in the range of 2–100 mg/L for D- and L-2-hydroxyglutaric acid in urine. The precision (relative standard deviation%) was obtained at about 7%. For D- and L-2-hydroxyglutaric acids, the limits of detection were 0.567 and 0.497 mg/L, respectively.     

The calculation of transition probabilities for atomic oxygen

In this contribution we present scanning tunnelling microscopy (STM) and spectroscopy (STS) investigations on isolated cobalt clusters in contact with Ge(001). Mass-filtered nanoparticles with diameters ranging from 3 to 11 nm are generated using an arc cluster ion source (ACIS) and deposited under soft landing conditions (E_kin/atom < 0.5 eV). Since the tip radius is of the same order as the nanoparticle diameters the recorded STM images are significantly affected by tip folding. By means of the “blind reconstruction method" it is possible to approximate the tip shape. After a respective deconvolution of the image structural features of the particle facets become observable. According to the equilibrium shape of the clusters being a truncated octahedron in the size range under investigation, hexagonal and rectangular features appear in the images. STS is sensitive to occupied and unoccupied states near the Fermi level and reveals the existence of distinct states in the tunnelling conductivity of the substrate as well as on the clusters. The richly structured density of states of the germanium surface serves here as tip condition test. First measurements of the tunnelling conductivity of the Co_N/Ge(001) are presented and discussed.     

Syntheses,IR spectra,thermal properties and crystal structures of novel cyano-bridged polymeric complexes of zinc and cadmium with tetracyanoplatinate

Two novel one-dimensional polymeric cyano-bridged platinum(II) complexes of N-(2-hydroxyethyl)-ethylenediamine (hydeten), [M^II(hydeten)Pt(CN)₂(μ-CN)₂]_n (M^II = Zn^II (1) and Cd^II (2)), were synthesized and characterized by physico-chemical methods (elemental analysis, IR spectroscopy and thermoanalytical measurements) and X-ray diffraction. Thermal behaviours of 1 and 2 were followed using TG and DTA (DSC) techniques. The 1D chain structures of 1 and 2 were verified by X-ray diffraction studies. According to the positions of the bridging cyano groups, in complex 1 the polymeric chains are built up via the 2,2-CT type, while in complex 2 the polymeric chains are built up via the 2,2-TT type.     

Thermal study of ruthenium(II) complexes containing pyridine-2,6-diimines

Thermal behaviors of mono-and binuclear Ru(II)-pydim complexes: [PydimCl₂RuL] (Pydim: pyridine-2,6-diimine; 2: L=NCMe; 3: L=PPh₃) and [PydimCl₂Ru(L-L)RuCl₂Pydim] (4: L-L=pyrazine; 5: L-L=4,4′-bipyridine) have been studied in nitrogen atmosphere using TG/DTG and DTA techniques. The decompositions of complexes occur in stepwise. The values of activation energy, E _a, and reaction order, n of the thermal decomposition were calculated by means of several methods such as Coats-Redfern (CR), MacCallum-Tanner (MT), Horowitz-Metzger (HM), van Krevelen (vK), Madhusudanan-Krishnan-Ninan (MKN) and Wanjun-Yuwen-Hen-Cunxin (WYHC) based on the single heating rate. Most appropriate method was determined for each decomposition step according to the least-squares linear regression.     

Liouville-type results for semilinear elliptic equations in unbounded domains

This paper is devoted to the study of some class of semilinear elliptic equations in the whole space:

Effect of TMAB concentration on structural,mechanical and corrosion properties of electrodeposited Ni–B alloys

The influence of trimethylamine borane (TMAB) concentration as a boron (B) source on the structural and corrosive properties of Ni–B alloy coatings produced by electrodeposition was investigated. The crystal structure of the Ni–B coatings is influenced by the B content in the coating, having a slight (220) preferred orientation. The B content in the coating increased from 16 to 34 at.% with the corresponding increase in the concentration of TMAB from 1 to 20 g/L, while interestingly retaining a crystal structure. The hardness of the coatings increased with increasing B content owing to the formation of smaller crystallites. An increase in B content in the alloy coatings, led to a shift in the E_corr values to more anodic potentials, indicating increase corrosion protection for the Ni–B coatings. This study achieved to reach 34 at.% B content in Ni–B alloy coatings produced by electrodeposition while preventing amorphization of the coating layer.     

The Determination of Timolol Maleate Using Silver/Tannic Acid/Titanium Oxide Nanocomposite as an Electrochemical Sensor in Real Samples

Herein, a portable and cost-effective electrochemical sbased on Silver/tannic acid/titanium dioxide/glassy carbon electrode (Ag/TA@ TiO₂/GCE) was fabricated to determine timolol(TM) assay. The Ag/TA@TiO₂/GCE offered an irreversible oxidation peak at +0.99 V, and exhibited an extraordinary electrochemical performance with a wide linear working ranges from 0.01–0.84 and 0.84–49.0 μM and a low detection limit of 5.2 nM. The detection of TM in the presence of interfering agents and real samples was also analyzed. The sensor‘s selectivity was studied by comparing the binding of TM, propranolol, nebivolol, and metoprolol. The developed electrochemical sensing platform could have promising potential for the determination of TM in clinical samples.     

Sol–gel synthesis of 3-(triethoxysilyl)propylsuccinicanhydride containing fluorinated silane for hydrophobic surface applications

In this paper, novel fluorinated silane compound was prepared by adding hydroxyl terminated Fluorolink D10H oligomer to 3-(triethoxysilyl)propylsuccinicanhydride. The obtained silane system was independently composed with 3-Aminopropyltrimethoxysilane, 3-Glycidyloxypropyltrimethoxysilane and 3-Glycidyloxypropyltriethoxysilane and, then the prepared coating solutions were applied to glass surface by spin-coating method. The chemical bonding between groups in system was investigated by Fourier Transform Infrared Spectroscopy analyses. The elemental composition of coatings was determined using Energy Dispersive X-ray Spectroscopy analyses. Its structure and surface properties were analyzed by scanning electron microscopy, atomic force microscopy, contact angle measurement and Ultraviolet–visible Absorption Spectroscopy. The amounts of fluorine on the coatings prepared with GF20-D10H-AMMO, GF20-D10H-GLYEO and GF20-D10H-GLYMO are 31, 32 and 34% at, respectively. Transparent coatings with smooth surface and uniform thickness were observed. The coatings had nanoscale roughness. The contact angles of coatings for water ranged from 88 to 107^o, and that of n-hexadecane ranged from 53 to 60^o.     

Synthesis and antimicrobial activity of Ag(I)‐N‐heterocyclic carbene complexes derived from benzimidazol‐2‐ylidene

Novel benzimidazol‐2‐ylidene carbene complexes of Ag(I) were prepared by interaction of the corresponding benzimidazolium salt with Ag₂O in dichloromethane. Their structures were characterized by elemental analyses, ¹H‐NMR, ¹³C‐NMR and IR spectroscopy techniques. All compounds studied in this work were screened for their in vitro antimicrobial activities against the standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and the fungi Candida albicans and Candida tropicalis. The new complexes were found to be effective antimicrobial activity against a series of bacteria and fungi. Copyright © 2010 John Wiley & Sons, Ltd.