Effect of thermal and chemical treatment on the structure and composition of nanodiamonds

The effect of chemical and thermal treatment on structural characteristics and chemical composition of detonation synthesis ultradispersed diamonds (UDDs) was studied. UDDs of five different producers were compared. Special attention was paid to structural characteristics of samples (size of coherent scattering regions, aggregation), which were determined by SEM, AFM, and X-ray diffraction methods. Impurities were analyzed by methods of mass spectrometry, atomic and absorption analysis, and X-ray spectral analysis.     

Kinetic relationships of metal filling of epoxy resin by in situ reduction of silver nitrate

The kinetics of metal filling of ED-20 epoxy oligomer by its action on AgNO₃ in the temperature interval 50–90°C was studied.     

Correction to: Finding False Paths in Sequential Circuits

Russian Physics Journal - A reference on the grant “The study was partially supported by Russian Science Foundation research project №14-19-00218” has been missed.     

Oxidative activity of organometallic compounds in relation to the coenzymes NADH and NADPH

Kinetic investigations of the interaction of Hg and Sn-containing organometallic compounds with NADH and NADPH using spectro-photometric methods have shown that these compounds may act as oxidizing agents in relation to the coenzyme. Their oxidative activity depends on the nature and number of organic groups in the molecule. Comparison of the kinetic data for the activity of Hg and Sn compounds with those for Fe porphyrins imitating the active centers of redox enzymes indicates the competitiveness of the organometallic compounds and models of natural electron acceptors.M. V. Lomonosov Moscow State University, Moscow 119899, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1036–1040, August, 1999.     

Interpretation of hypsochromic and bathochromic shifts of vibrational frequencies of a cation exchanger

Structures of a representative fragment of a sulfocation exchanger in the form of alkali metal salts were optimized using the Gaussian-03 program package. Frequencies of stretching vibrations of the sulfo group were calculated for structures of the contact ion and hydrate-separated ion pairs. A comparison of the calculated and experimental values of hypsochromic (bathochromic) shifts of the frequencies of stretching vibrations of the sulfo group due to the cation field suggests that the ion pair in the studied systems dissociates. The calculated IR spectra of the representative fragment of the sulfocation exchanger can be used as calculated benchmarks in analyzing substances using expert systems.     

Nucleophilic substitution inβ-chloroacrylic acids by cyclic thioamides

The nucleophilic substitution of halogen inβ-chloroacrylic acids by benzoxazoline-2-thione and benzimidazoline-2-thione was studied by PMR spectroscopy. It is shown that the reaction with benzimidazoline-2-thione proceeds with 100% retention of configuration, whereas only the trans isomer is isolated with benzoxazoline-2-thione because of prior isomerizaton of the starting acid.     

Quasi-elastic scattering of neutrons by a water dispersion of nanodiamonds

Data on quasi-elastic neutron scattering by a water dispersion of nanodiamonds and a pure water as a supporting system has been analyzed. The observed difference in the quasi-elastic neutron scattering spectra is interpreted using two different approaches developed to date for describing the behavior of a solvent in the cases of low and moderate concentrations of carbon nanoparticles (for example, fullerenes, nanotubes, ultradispersed diamonds). Within the first approach, it is assumed that the influence of dissolved nanoparticles leads to an insignificant change in the properties of the solvent. Within the second approach, the properties of the solvent are assumed to be invariable as compared to those of the pure liquid, except for a narrow boundary region of the order of two to three atomic layers near the surface of nanoparticles, where the properties of the solvent change drastically. The explanation of the effect within the second approach seems to be more reliable despite the apparent complication of the mathematical treatment of the experiment.     

Light‐Gated Synthetic Protocells for Plasmon‐Enhanced Chemiosmotic Gradient Generation and ATP Synthesis

Herein, we present a light‐gated protocell model made of plasmonic colloidal capsules (CCs) assembled with bacteriorhodopsin for converting solar energy into electrochemical gradients to drive the synthesis of energy‐storage molecules. This synthetic protocell incorporated an important intrinsic property of noble metal colloidal particles, namely, plasmonic resonance. In particular, the near‐field coupling between adjacent metal nanoparticles gave rise to strongly localized electric fields and resulted in a broad absorption in the whole visible spectra, which in turn promoted the flux of photons to bacteriorhodopsin and accelerated the proton pumping kinetics. The cell‐like potential of this design was further demonstrated by leveraging the outward pumped protons as “chemical signals” for triggering ATP biosynthesis in a coexistent synthetic protocell population. Hereby, we lay the ground work for the engineering of colloidal supraparticle‐based synthetic protocells with higher‐order functionalities.