Peculiarities of Interaction of Electric Arc Plasma and Composite Electrodes’ Working Surface

The aim of this work is complex investigations of interaction between electric arc discharge plasma and Cu-Mo composite electrodes’ working surface. The destructions of working layer of such electrodes, caused by discharge plasma influence, were studied. The mutual correlation of plasma properties and destruction behavior of electrodes surface was found

Discrete kink dynamics in hydrogen-bonded chains I: The one-component model

We study topological solitary waves (kinks and antikinks) in a nonlinear one-dimensional Klein-Gordon chain with the on-site potential of a double-Morse type. This chain is used to describe the collective proton dynamics in quasi-one-dimensional networks of hydrogen bonds, where the on-site potential plays role of the proton potential in the hydrogen bond. The system supports a rich variety of stationary kink solutions with different symmetry properties. We study the stability and bifurcation structure of all these stationary kink states. An exactly solvable model with a piecewise ``parabola-constant'' approximation of the double-Morse potential is suggested and studied analytically. The dependence of the Peierls-Nabarro potential on the system parameters is studied. Discrete travelling-wave solutions of a narrow permanent profile are shown to exist, depending on the anharmonicity of the Morse potential and the cooperativity of the hydrogen bond (the coupling constant of the interaction between nearest-neighbor protons).Comment: 12 pages, 20 figure

Thermal plasma of electric arc discharge in air between composite Cu-C electrodes

The complex technique of plasma property studies is suggested. As the first step the radial profiles of temperature and electron density in plasma of free burning electric arc discharge in air between Cu-C composite and brass electrodes, as well as copper electrodes in air flow, were measured by optical emission spectroscopy techniques. As the next step the radial profiles of electric conductivity of plasma mixture were calculated by solution of energy balance equation. The electron density is obtained from electric conductivity by calculation in assumption of local thermodynamical equilibrium in plasma.Предложена комплексная методика исследования плазмы. На первом этапе методами оптической эмиссионной спектроскопии проводились измерения радиальных распределений температуры и электронной концентрации в плазме электродугового разряда в воздухе между композитными Cu-C и латунными электродами, а также медными электродами в потоке воздуха. На следующем этапе рассчитывались радиальные распределения электропроводности плазменной смеси путем решения уравнения энергетического баланса. Распределение электронной концентрации получено из электропроводности плазмы в допущении локального термодинамического равновесия.Запропонована комплексна методика дослідження плазми. На першому етапі методами оптичної емісійної спектроскопії проводились дослідження радіальних розподілів температури та електронної концентрації в плазмі електродугового розряду в повітрі між композитними Cu-C та латунними електродами, а також мідними електродами в потоці повітря. Наступним кроком розраховувались радіальні розподіли електро-провідності плазмової суміші шляхом розв’язку рівняння енергетичного балансу. Розподіл електронної концентрації отримали з електропровідності плазми в припущенні локальної термодинамічної рівноваги

The effect of S-substitution at the O6-guanine site on the structure and dynamics of a DNA oligomer containing a G:T mismatch

The effect of S-substitution on the O6 guanine site of a 13-mer DNA duplex containing a G:T mismatch is studied using molecular dynamics. The structure, dynamic evolution and hydration of the S-substituted duplex are compared with those of a normal duplex, a duplex with Ssubstitution on guanine, but no mismatch and a duplex with just a G:T mismatch. The S-substituted mismatch leads to cell death rather than repair. One suggestion is that the G:T mismatch recognition protein recognises the S-substituted mismatch (GS:T) as G:T. This leads to a cycle of futile repair ending in DNA breakage and cell death. We find that some structural features of the helix are similar for the duplex with the G:T mismatch and that with the S-substituted mismatch, but differ from the normal duplex, notably the helical twist. These differences arise from the change in the hydrogen-bonding pattern of the base pair. However a marked feature of the S-substituted G:T mismatch duplex is a very large opening. This showed considerable variability. It is suggested that this enlarged opening would lend support to an alternative model of cell death in which the mismatch protein attaches to thioguanine and activates downstream damage-response pathways. Attack on the sulphur by reactive oxygen species, also leading to cell death, would also be aided by the large, variable opening

PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood Circulation

Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NP) and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly-(g-glutamic acid) (gPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pHs, at elevated temperatures and in serum. Morever, the polymer-coated SWNTs exhibit remarkably long blood circulation (t1/2 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultra-long blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery

РАЗРАБОТКА ТЕХНОЛОГИИ И НОРМАТИВНОЙ ДОКУМЕНТАЦИИ НА ИМПОРТОЗАМЕЩАЮЩИЙ ПРОДУКТ ПЕРЕРАБОТКИ БРОККОЛИ

The aim of the present investigation was development of an efficient technology for obtaining powders from fresh broccoli; determination of the possibility of using domestic production of broccoli as an import-substituting product; development of regulatory documentation for broccoli powders for the food industry. The research was carried out jointly with the representatives of the Federal Scientific cen-ter of vegetable production on an experimental basis in 2016. The domestic Tonus variety of broccoli (Federal Scientific center of vegetable production) and the Maraton F1 hybrid (France), differing in appearance, vegetative period, biochemical and physical characteristics were chosen. Technology of broccoli powder production from domestic and imported products was developed using two methods of drying convection and lyophilization. The gentle drying conditions of broccoli freeze drying compared to convective drying technology provided higher content of both vitamin C and polyphenols in the final powder. Comparative studies of organoleptic and physico-chemical properties of powders obtained from domestic and imported broccoli demonstrated close quality parameters, indicating the possibility of effective domestic broccoli utilization and import substitution. For the first time in the Russian Federation, the "Organization Standard" was developed for regulation of the quality parameters of broccoli powders intended for use in the food industry.Цель данных исследований заключалась в разработке эффективной технологии получения порошков из свежей капусты брокколи; установлении возможности использования брокколи отечественного производства как импортозаме-щающего продукта; разработке нормативной документации на порошки брокколи для использования в пищевой промыш-ленности. Исследования проводили совместно с представителями ФГБНУ ВНИИССОК на экспериментальной базе в посевной период 2016 года. К исследованиям принята капуста брокколи: отечественный сорт Тонус (селекции ФГБНУ ВНИИССОК) и гибрид Маратон F1 (производитель Франция), различающиеся по внешним признакам, продолжительности вегетации, биохимическим и физическим характеристикам. Технология порошков брокколи из сырья отечественного и импортного производств осуществлена с применением двух способов сушки – конвективной и лиофильной. Щадящие условия высушивания свежего продукта при лиофильной сушке обеспечивали повышенное содержание в конечном порошке как витамина С, так и полифенолов по сравнению с порошками конвективной сушки. Сравнительными исследованиями органолептических и физико-химических свойств порошков, полученных из сырья разного происхождения, установлены близкие показатели качества, что является обоснованием для использования отечественного сырья в качестве импортозамещающего. Впервые в Российской Федерации разработан «Стандарт организации», призванный регламентировать показатели качества порошков брокколи, предназначенных для использования в пищевой промышленности