Reversible Dimerization of Human Serum Albumin

Pulsed Dipolar Spectroscopy (PDS) methods of Electron Paramagnetic Resonance (EPR) were used to detect and characterize reversible non-covalent dimers of Human Serum Albumin (HSA), the most abundant protein in human plasma. The spin labels, MTSL and OX063, were attached to Cys-34 and these chemical modifications of Cys-34 did affect the dimerization of HSA, indicating that other post-translational modifications can modulate dimer formation. At physiologically relevant concentrations, HSA does form weak, non-covalent dimers with a well-defined structure. Dimer formation is readily reversible into monomers. Dimerization is very relevant to the role of HSA in the transport, binding, and other physiological processes.     

2H Solid-State NMR Spectroscopy Reveals the Dynamics of a Pyridine Probe Interacting with Coordinatively Unsaturated Metal Sites of MIL-100(Al) Metal–Organic Frameworks

Coordinatively unsaturated metal sites (CUS) play an important role in catalysis by metal-organic frameworks (MOF). Being an intrinsic part of the framework the CUS take the role of acidic sites active in industrially relevant processes such as condensation or oxidation reactions. The key step of such reactions represents the coordination of the reagents to CUS. In MOFs the mechanism of the reagent interaction with CUS is poorly understood. Herein, we characterize the interaction of a widely used acidity probe pyridine with CUS of MIL-100(Al) MOF by means of the ²H solid-state NMR spectroscopy. ²H NMR reveals that pyridine species, which are interacting with CUS and the ones which are coordinated to the Al−OH site, exhibit different motional behavior. ²H NMR line shape as well as T₁, T₂ relaxation analyses for [D₅]pyridine adsorbed in MIL-100(Al) allowed us to perform a detailed characterization of pyridine dynamics in both states including the kinetics of the exchange process between these adsorption states.     

Raman imaging and photodegradation study of phthalocyanine containing microcapsules and coated particles

We present the results of using Raman molecular imaging and atomic force microscopy (AFM) investigation of the composition, stability, and photodegradation of polyelectrolyte multilayer microcapsules and coated microparticles containing copper–phthalocyanine and iron–phthalocyanine. The influence of laser light on degradation of these phthalocyanine dyes embedded in the walls of polyelectrolyte multilayer capsules and shells of microparticles was studied by both AFM and Raman molecular imaging, but only the latter technique gave information on dynamics of photodegradation. Raman peak assignment was performed according to theoretical calculations. The degradation rate of phthalocyanine dyes is estimated from Raman signal measurements and a model is proposed to account for the degradation rate. Practical applications of our approach are outlined. Copyright © 2011 John Wiley & Sons, Ltd.     

Amines-boron trifluoride complexes as catalyst for cold curing epoxy resin ED-20 using anhydride curing agents

Russian Journal of Applied Chemistry - The reaction of the anhydride curing epoxy resin ED-20 in the presence of boron trifluoride-amines was investigated in the temperature range 303–393 K....     

Problems of higher and secondary school interaction

Conventional methods and techniques of effective interaction between higher and secondary school have been analyzed. This effective interaction has developed successfully until present and has ensured teaching continuity from school to university. It has been shown that introduction of the External Independent Evaluation (EIE) in 2007 led to revolutionary-evolutionary losses of the connection between secondary and higher school. Therefore, a possibility to teach high quality professionals capable of solving non-standard problems and accumulating new ideas has deteriorated significantly. Ways to restore the relationship between higher and secondary school have been proposed in order to save the high scientific potential of the country. These options included introduction of a general chemistry course in higher educational institutions, preservation of chemistry as a natural science subject in secondary schools, and renewal of universities’ work with applicants based on their positive experience in the past.     

PrCo1−xFexO3 perovskite powders for possible photocatalytic applications

Research on Chemical Intermediates - Mixed perovskites PrCo1?xFexO3 have been synthesized by the solgel citrate route with the following calcinations in air at 600–800 °C....     

Regioselectivity of the acidolysis of 2-(chloromethyl)oxirane with aromatic acids in the presence of organic bases

Regioselectivity of the reaction of 2-(chloromethyl)oxirane with aromatic acids in the presence of tertiary amines and tetraalkylammonium halides has been studied. Opening of the oxirane ring follows simultaneously S_N2 and borderline S_N2 mechanisms. The regioselectivity of the acidolysis of substituted oxiranes is determined by acid-base properties of the reactants and catalysts and steric factor. The regioselectivity increases as the contribution of the S_N2 mechanism increases.