Proficiency tests to evaluate commercially available IVD kits for glucose and cholesterol measurements

The first proficiency testing round 630-IL-1002, was carried out with a Reference Material DMR-180a with reference values obtained by using gas chromatography isotope dilution mass spectrometry methods, in which glucose, cholesterol and creatinine were measured. The serum pool was obtained from blood donors and all the analytes were at the normal concentration in Mexican population. The laboratories participants used different field methods to measure the analytes. The Mexican compulsory standard NOM-064-SSA1-1993 “specifications for equipments in vitro diagnostic (IVD)” requests 5% precision and 5% maximum bias of the IVD equipments in the measurements of analytes like glucose and cholesterol. The results obtained by field laboratories in the proficiency testing round are compared to the reference value and uncertainty provided by the National Metrology Institute (CENAM). The quality of measurements is dependent not only on the laboratory competence but also on the methods used by those commercially available IVD kits. It is concluded that quality assessment of measurements in clinical laboratories should be critically evaluated by using stable and certified reference materials. Presented at MEFNM 2008, September 2008, Budapest, Hungary.     

LC Determination of Gallic Acid in Preparations Derived from Schinus terebinthifolius Raddi

The aim of the present paper was to develop and validate a method to determine gallic acid and tannins by LC. Validation was carried out in accordance with Brazilian Resolution 899/2003. The method showed satisfactory results for precision, accuracy, specificity and linearity. Variations on the composition and flow rate of the mobile phase influenced the peak area and retention time. The method was applied to determine the amount of hydrolysable tannins in preparations containing Schinus terebinthifolius Raddi.

     

Synthesis, structures and phase transitions in the double perovskites Sr2−xCaxCrNbO6

The synthesis and crystal structures of nine members of the rock-salt ordered double perovskites Sr_2−xCa_xCrNbO₆ is presented. The crystal structures of the end members of the series Sr₂CrNbO₆ and Ca₂CrNbO₆ were refined using powder neutron diffraction data and are cubic in and monoclinic in P2₁/n, respectively, in both cases there being considerable anti-site Cr-Nb mixing. Variable temperature and/or composition studies suggest a direct first-order P2₁/n to transition, a suggestion supported by selected area electron diffraction studies.     

Overriding Intrinsic Reactivity in Aliphatic C−H Oxidation: Preferential C3/C4 Oxidation of Aliphatic Ammonium Substrates

The site‐selective C?H oxidation of unactivated positions in aliphatic ammonium chains poses a tremendous synthetic challenge, for which a solution has not yet been found. Here, we report the preferential oxidation of the strongly deactivated C3/C4 positions of aliphatic ammonium substrates by employing a novel supramolecular catalyst. This chimeric catalyst was synthesized by linking the well‐explored catalytic moiety Fe(pdp) to an alkyl ammonium binding molecular tweezer. The results highlight the vast potential of overriding the intrinsic reactivity in chemical reactions by guiding catalysis using supramolecular host structures that enable a precise orientation of the substrates.     

Poly(diol-co-citrate)s as novel elastomeric perivascular wraps for the reduction of neointimal hyperplasia

The synthesis of poly(diol-co-citrate) elastomers that are biocompatible with vascular cells and can modulate the kinetics of the NO release based on the diol of selection is reported. NO-mediated cytostatic or cytotoxic effects can be controlled depending on the NO dose and the exposure time. When implanted in vivo in a rat carotid artery injury model, these materials demonstrate a significant reduction of neointimal hyperplasia. This is the first report of a NO-releasing polymer fabricated in the form of an elastomeric perivascular wrap for the treatment of neointimal hyperplasia. These elastomers also show promise for other cardiovascular pathologies where NO-based therapies could be beneficial.     

The Violation of Bell-CHSH Inequalities Leads to Different Conclusions Depending on the Description Used

Since the experimental observation of the violation of the Bell-CHSH inequalities, much has been said about the non-local and contextual character of the underlying system. However, the hypothesis from which Bell’s inequalities are derived differ according to the probability space used to write them. The violation of Bell’s inequalities can, alternatively, be explained by assuming that the hidden variables do not exist at all, that they exist but their values cannot be simultaneously assigned, that the values can be assigned but joint probabilities cannot be properly defined, or that averages taken in different contexts cannot be combined. All of the above are valid options, selected by different communities to provide support to their particular research program.     

Peptide Amphiphile Supramolecular Nanostructures as a Targeted Therapy for Atherosclerosis

The rising prevalence of cardiovascular disease worldwide necessitates novel therapeutic approaches to manage atherosclerosis. Intravenously administered nanostructures are a promising noninvasive approach to deliver therapeutics that reduce plaque burden. The drug liver X receptor agonist GW3965 (LXR) can reduce atherosclerosis by promoting cholesterol efflux from plaque but causes liver toxicity when administered systemically at effective doses, thus preventing its clinical use. The ability of peptide amphiphile nanofibers containing apolipoprotein A1–derived targeting peptide 4F to serve as nanocarriers for LXR delivery (ApoA1‐LXR PA) in vivo is investigated here. These nanostructures are found to successfully target atherosclerotic lesions in a mouse model within 24 h of injection. After 8 weeks of intravenous administration, the nanostructures significantly reduce plaque burden in both male and female mice to a similar extent as LXR alone in comparison to saline‐treated controls. Furthermore, they do not cause increased liver toxicity in comparison to LXR treatments, which may be related to more controlled release by the nanostructure. These findings demonstrate the potential of supramolecular nanostructures as safe, effective drug nanocarriers to manage atherosclerosis.     

LC Determination of Gallic Acid in Preparations Derived from Schinus terebinthifolius Raddi

The aim of the present paper was to develop and validate a method to determine gallic acid and tannins by LC. Validation was carried out in accordance with Brazilian Resolution 899/2003. The method showed satisfactory results for precision, accuracy, specificity and linearity. Variations on the composition and flow rate of the mobile phase influenced the peak area and retention time. The method was applied to determine the amount of hydrolysable tannins in preparations containing Schinus terebinthifolius Raddi.     

Syntheses and crystal structures of organoindium(III) 1-D coordination polymers with bis(diphenylphosphino)alkane dioxides

Abstract

Bromomethyl-dibromo-indium(III), Br₂InCH₂Br, obtained from indium monobromide and methylene dibromide, reacts with hard and soft donor ligands to afford the corresponding indium(III) organometallic complexes. In this work, we investigated the conditions to prepare adducts of Br₂InCH₂Br using bis(diphenylphosphino)alkane dioxides acting as hard ligands. We report here the synthesis and crystal structures of two 1-D coordination polymers with the hard donor ligands Ph₂P(O)(CH₂)_mP(O)Ph₂ (m = 2, dppeO₂ and m = 6, dpphO₂). Compounds 1 and 2 with formulas [Br₂In(CH₂Br)(dppeO₂)]_n (1) and [Br₂In(CH₂Br)(dpphO₂)]_n (2) were characterized by IR and Raman spectroscopy and elemental analysis. We also obtained an ionic indium(III) compound with dppeO₂ acting as a chelating ligand with formula [InBr₂(dppeO₂)₂][InBr₃(CH₂Br)] (3). The crystal structures were determined for 1–3 using single crystal X-ray diffractometry. The geometry around the In(III) can be described as a trigonal bipyramid in 1 and 2, and the chains were packed onto the plane giving layers that are stabilized mainly by intermolecular interactions. Compound 3 has a square bipyramidal In(III) cation with formula [Br₂L₂In]⁺ and tetrahedral organoindium(III) anion with formula [Br₃InCH₂Br]^–. Hirshfeld surface analysis employing 2-D fingerprint plots have been used to analyze intramolecular and intermolecular interactions present in the solid state of the structures.     

Vibrational and valence photoelectron spectroscopies, matrix photochemistry, and conformational studies of ClC(O)SSCl

ClC(O)SSCl was prepared by an improved method by the reaction of [(CH(3))(2)CHOC(S)](2)S with SO(2)Cl(2) in hexane. The photoelectron spectra in the gas phase present four distinct regions, corresponding to ionizations from electrons formally located at the S, O, and Cl atoms and at the C═O bond. The vibrational IR and Raman spectra of the liquid were interpreted in terms of the most stable syn-gauche conformer (the O═C double bond syn with respect to the S-S single bond and the C-S single bond gauche with respect to the S-Cl single bond) in equilibrium with the less stable anti-gauche form, both occurring in two enantiomeric forms. The randomization process between the conformers was induced by broad-band UV-visible irradiation in matrix conditions, and several photoproducts were identified by FTIR spectroscopy. The experimental results were complemented by theoretical calculations.