Russian Journal of Physical Chemistry B最新文献

In this work, using coarse-grained molecular modeling methods, the interactions of DNA-binding protein from starved cells (Dps) of the bacterium Escherichia coli with DNA sections of various lengths and composition are investigated. The binding features in two-dimensional crystals of the Dps protein are studied. Using free energy search methods—thermodynamic integration and linear interaction energy—the most favorable conditions for the binding of DNA and Dps are determined.

The chemically inert luminophore, the chemiluminescence enhancer 1,10-phenanthroline-tris(thenoyl-trifluoroacetonate) of trivalent europium, increases the intensity of light emission by an order of magnitude during the initiated oxidation of lipid samples of vegetable origin (sunflower oil). The introduction of a light enhancer into the chemiluminescent system leads to a change in the kinetic profile, removing the characteristic peaks on the kinetic curves at the end of the induction period of the oxidation process, but without changing the induction period itself. Using mathematical computer modeling based on a kinetic scheme of 23 elementary reactions, it is shown that the observed kinetic behavior can be rationalized by a disproportionate increase in the quantum yields of chemiluminescence derived from different electronically excited products (light emitters) formed during the oxidation process.

Earlier the efficiency of a stand in form of the open-end Π-shape tube for deflagration-to-detonation transition (DDT) of propane—air mixtures at normal pressure was shown. In this work, the study of the DDT is extended to the mixtures modeling real gaseous pyrolysis products of polyethylene and rubber-containing industrial and domestic waste. Modeling mixtures with air contain Н₂, СН₄, С₂Н₆, С₂Н₄, С₃Н₈ and С₃Н₆ in stoichiometric or lean concentration based on the experimental data presented in the literature. Conditions when the DDT can be reached (stand design, initial pyrolysis products mixture concentration) are defined. Measurements of the temperature of the mixture passed through the stand in addition to dynamic measurements allow to define the character of the processing: DDT, fast or slow deflagration. It has been shown that propane as a model fuel may be used instead of pyrolysis gases mixtures when studying DDT. The results supposed to be helpful for the waste recycling industrial setups engineering.

This paper accentuates the question, why magnetic field kills cancer. Spin selective radical pair mechanism of p53 phosphorylation is formulated to elucidate enigmatic magnetic field effect on the cancer. The idea is suggested to use ferromagnetic nanoparticles to induce local magnetic fields in tumor and stimulate the death of cancer.

This article studies the thermal denaturation of a plasminogen molecule during induced oxidation by hypochlorite in a range of concentrations (30, 62.5, 125, and 250 µM). Using differential scanning calorimetry, it is determined that in the presence of an oxidizing agent, the enthalpy of denaturation of the plasminogen molecule decreases. This is most noticeable for the peak showing the melting of the K4–K5 kringle domains. These results are consistent with the previously obtained data on the oxidative modification of amino acid residues of plasminogen treated with different concentrations of hypochlorite using the HPLC-MS/MS method. Taken together, these data and the results of previous studies indicate that the structure of full-length plasminogen is adapted to moderate HOCl-induced oxidation.

We present the results of quasiclassical trajectory simulation of dissociation of CsBr molecules in collisions with Xe atoms (at collision energies ranging from 3 to 12 eV) on two diabatic potential energy surfaces differing in the parameters of the potential well and of the repulsive wall for the pairwise interaction potential between the xenon atom and the bromide anion. The dynamical characteristics of both the dissociation channels (of the formation of the atomic ions and of that of the ionic complex XeCs⁺) are practically independent of the interaction potential between Xe and Br^–.

Bilirubin (BR), a bile pigment with photochemical activity, plays an important role in the body. The photonics (photophysics and photochemistry) of BR continues to attract scientific and practical interest from researchers to this day. This is due to the fact that its molecule is capable of ultrafast photoisomerization processes and also contains two interacting dipyrromethenone chromophores. Furthermore, the photochemical reactions of BR are used in the widespread phototherapy method of neonatal jaundice (neonatal hyperbilirubinemia (NHB)), carried out to reduce the level of BR in the body. This review briefly discusses the photonics of BR and its main photochemical reactions in the phototherapy of NHB.

The dependence of the degree of sorption of potassium dichromate by aerogels based on reduced graphite oxide and superparamagnetic iron oxide nanoparticles of the rGO⋅Fe₃O₄ composition on the mass of the sorbent, acidity, and temperature of the medium is studied. It is shown that in order to increase the degree of potassium dichromate sorption by the rGO⋅Fe₃O₄ magnetic aerogel, the process is best carried out at room temperature in media with low pH value lower than 5. The results obtained make it possible to propose aerogels rGO⋅Fe₃O₄ as environmentally friendly sorbents for water purification from the carcinogenic substance of potassium dichromate. The proposed materials after completion of the sorption process can be completely removed from the reaction medium using an external magnetic field, thereby preventing them from acting as pollutants. It is important to note that the described 3D structures based on GO and nanoparticles of superparamagnetic iron oxide Fe₃O₄ are of practical importance for the treatment of wastewater from enterprises using an oxidative method for removing phenols, cresols, and cyan-containing substances from impurities using potassium dichromate and sulfuric acid.

The influence of cobalt additives on the phase composition, structural parameters, and morphology of indium oxide containing a mixture of crystalline phases is studied. The hydrothermal synthesis method is used to obtain the corresponding systems. It is shown that during the hydrothermal reaction, a mixture of phases of indium hydroxide and oxyhydroxide is formed, which, in turn, after thermal decomposition, transform into cubic and rhombohedral indium oxide, respectively. Depending on the concentration of the introduced cobalt, the ratio between the phases changes. At a concentration of 0.05 at % Co, the cubic phase is prevalent, while at an introduction of 0.25 at %, the rhombohedral phase is prevalent compared to the undoped sample. An increase in the concentration of cobalt leads to a decrease in the particle size, as well as an increase in the specific surface area and porosity of the composites. At the same time, the introduction of cobalt does not significantly affect the morphology of the resulting systems.

The aim of this study is to consider the photogeneration of charge carriers in nano-structured blends of the donor (D) and acceptor (A) materials. The optical excitation photons absorbed in one of these materials produce intramolecular excitons which can diffuse into the D–A interface and form interfacial CT states at the interface. The interfacial CT state dissociates into a geminate pair of the nonequilibrium mobile electron and hole. In this study, an empirical model describing thermalization of the nonequilibrium charges within the Coulomb well is proposed. The efficiency of the interfacial CT state’s dissociation into a pair of free charges is found as a function of the electric field applied, effective temperature, and diffusion length of the nonequilibrium electron-hole pairs.