Modification of cathode structure by introduction of CNT for air-breathing DMFC

Optimization of the structure and texture of the cathode catalyst layer for air-breathing DMFC has been studied. Application of carbon nanotubes (CNT) as an additive to the cathode catalyst layer resulted in the increase of BET surface area and porosity of the catalyst layer due to filamentous morphology of CNT. Best performance was observed at the intermediate CNT/catalyst ratio of 0.05. I–U polarization and impedance analysis indicated that the faster oxygen reduction reaction at the open cathode is responsible for the power density improvement. Excessive cathode porosity was not favorable due to the decrease of the effective ionic conductivity of the catalyst layer.     

Diaminofuroxan: Synthetic Approaches and Computer‐Aided Study of Thermodynamic Stability

Different approaches to synthesize diaminofuroxan are presented herein. Mathematical and quantum chemical methods were used to study the possible reasons for failures in the syntheses of diaminofuroxan. Additionally, structural isomers of this compound were generated. With the help of the results of quantum chemical calculations at levels of DFT B3LYP 6‐31G(d) and MP2 6‐31G(d), screening of the most stable isomeric forms in the gaseous phase and in water was performed. It was shown that diaminofuroxan is not the thermodynamically most stable isomer among its structural analogues.     

Computer Simulation of Decomposition Mechanisms for CL‐20, Hydrazine,and Their Binary System

An approach to simulate thermal destruction processes of energetic materials has been developed. It is based on the classification of structural features for nitro compounds and the experimental data regarding their decomposition mechanisms. This approach consists of the mathematical simulation of thermal decomposition mechanisms to predict the likely reactions that may occur during the destruction of organic compounds. On the basis of contemporary experimental data on the decomposition of energetic materials from various chemical classes, a set of semi‐empirical rules for modeling possible reaction pathways has been formulated. These rules allow the generation of a whole set of possible decomposition mechanisms for substances at different steps of their destruction. In this study, the suggested methodology is applied to 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (CL‐20) and hydrazine and to their binary energetic mixture. It has been shown that thermal decomposition of the binary system consists in decompositions of the separate compounds at the initial stage with subsequent collisions and interactions of the resultant intermediates and decomposition products at different stages. In addition to some experimentally found decomposition products, our simulation showed some other possible compounds among the final products.     

The antioxidant activity of Californian red wines does not correlate with wine age

A range of physico‐chemical properties of 21 Californian red wines from 1 to 28 years old were correlated with wine age. The level of monomeric phenolics and low molecular‐weight phenolic oligomers decreased with age, while the level of high molecular‐weight phenolics increased. On the other hand, total phenols given by the Folin–Ciocalteau method, antioxidant capacity determined using a controlled chain reaction of methyl linoleate and the intensity of the anodic peak determined by cyclic voltammetry (CV) did not show any significant correlation with wine age. Total phenols and the shapes of CV traces were more dependent on the grape variety and the particular viticultural and wine‐making practices rather than on wine age. At the same time, young and aged wines showed a pronounced difference in the shape of [O₂] traces recorded during the oxidation of methyl linoleate in a micellar solution inhibited by wine addition. Possible reasons why the antioxidant activity of red wines does not correlate with wine age are discussed. Copyright © 2006 Society of Chemical Industry     

Difluoromethylornithine (DFMO), an Inhibitor of Polyamine Biosynthesis,and Antioxidant N-Acetylcysteine Potentiate Immune Response in Mice to the Recombinant Hepatitis C Virus NS5B Protein

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.     

Search for New Three-, Four-Component Petasis,Passerini, Hantzsch,Kabachnic-Fields,Ugi Reactions with Organic Compounds of Phosphorus,Arsenic, Antimony and Bismuth

It is discovered a new three-, four-component Petasis, Passerini, Hantzsch, Kabachnic-Fields, Ugi reactions with of arsine, stibine and bismuthine in organometallic chemistry. Modifications were replaced to a nitrogen atom of classical reactions of atoms of phosphorus, arsenic, antimony and bismuth. It has been proposed a new mechanism for possible reactions.     

Surface Structure,Spectroscopic and Photocatalytic Activity Study of Polyaniline/TiO2 Nanocomposites

PANI （polyaniline） as a promising conducting polymer and photosensitizer has been used to prepare PANI/TiO2 （polyaniline/TiO2） nanocomposite as photocatalyst. TiO2 nanoparticles with size of 5-100 nm were encapsulated by PANI via the ＂in situ＂ polymerization of aniline on the surface of TiO2 nanoparticles. IR, SEM, EPR techniques were used to characterize the mechanism of electron interaction in PANI/TiO2 nanocomposite. The resulting PANI-modified TiO2 composites exhibit significantly higher photocatalytic activity than that of neat PANI on degradation of MB （methylen blue） aqueous solution under UV irradiation.     

Comparison of dispersants performance on the suspension Lu2O3:Eu stability and high-density compacts on their basis

The conditions for obtaining a stable Lu₂O₃:Eu³⁺ suspension of spherical particles with a diameter of 100 nm using three dispersants possessing an electrosteric stabilizing effect (Dolapix CE 64, Darvan 821 A, Darvan C-N) have been studied. It has been shown that in colloidal processing of ceramics the packing density and microstructure of green bodies can be controlled by regulating the interactions between ceramic particles in the suspension. The influence of the molecular weight and concentration of the dispersant on the stability of Lu₂O₃:Eu³⁺ suspensions containing 5-10 vol.% of the solid loading has been considered. It has been determined that use of Dolapix CE 64 with a concentration of 1 mass.% in the alkaline pH range allows to obtain suspensions with high stability and low viscosity (∼1.7 сP). Such suspensions were used to produce compacts with a maximum relative density of ∼52% and uniform density distribution by the pressure slip casting method. The obtained compacts were densified into translucent Lu₂O₃:Eu³⁺ ceramics by the vacuum sintering method.     

Cyanides,Arsenic, and Noble Metals in Abandoned Gold Ore Cyanidation Tailings and Surface Waters in a Permafrost Region (Transbaikal Territory,Russia)

Mine Water and the Environment - Geochemical and geophysical investigations were performed in an area of the Darasun ore cyanidation tailings impoundment, which is located in a permafrost region....