Fluorescent Organo-Antimony Compounds as Precursors for Syntheses of Redox-Active Trimeric and Dimeric Alkali Metal Antimonides: An Insight into Electron Transfer Reduction Processes

(Tip)2SbCl (1, Tip = 2,4,6-triisopropylphenyl) has been utilized as a precursor for the synthesis of distibane (Tip)4Sb2 (4) by one-electron reduction using KC8. Two-electrons reduction of 1 and 4 afforded...

Sulfide-Based Photocatalysts Using Visible Light, with Special Focus on In2S3, SnS2 and ZnIn2S4

Sulfides are frequently used as photocatalysts, since they absorb visible light better than many oxides. They have the disadvantage of being more easily photocorroded. This occurs mostly in oxidizing conditions; therefore, they are commonly used instead in reduction processes, such as CO2 reduction to fuels or H2 production. Here a summary will be presented of a number of sulfides used in several photocatalytic processes; where appropriate, some recent reviews will be presented of their behaviour. Results obtained in recent years by our group using some octahedral sulfides will be shown, showing how to determine their wavelength-dependent photocatalytic activities, checking their mechanisms in some cases, and verifying how they can be modified to extend their wavelength range of activity. It will be shown here as well how using photocatalytic or photoelectrochemical setups, by combining some enzymes with these sulfides, allows achieving the photo-splitting of water into H2 and O2, thus constituting a scheme of artificial photosynthesis.

Porous SiC and SiC/Cf Ceramic Microspheres Derived from Polyhydromethylsiloxane by Carbothermal Reduction

A simple and inexpensive method for the preparation of porous SiC microspheres is presented. Polysiloxane microspheres derived from polyhydromethylsiloxane (PHMS) cross-linked with divinylbenzene (DVB) were ceramized under conditions leading to the removal of oxygen from the material. The content of free carbon (Cf) in highly crystalline silicon carbide (SiC) particles can be controlled by using various proportions of DVB in the synthesis of the pre-ceramic material. The chemical structure of the ceramic microspheres was studied by elemental analysis for carbon and oxygen, 29Si MAS NMR, 13C MAS NMR, SEM/EDS, XRD and Raman spectroscopies, and their morphology by SEM, nitrogen adsorption and mercury intrusion porosimetries. The gaseous products of the thermal reduction processes formed during ceramization created a porous structure of the microspheres. In the SiC/Cf microspheres, meso/micro pores were formed, while in carbon-free SiC, microspheres macroporosity dominated.

Effect of the irrigation regime of rise on soil oxidation-reduction status

During the cultivation of rice in the field for 3 months, the required water layer is maintained. In these conditions, there are the processes that lead to changes in the composition of organic and mineral components of the soil, namely: removal of easily soluble substances and mobile forms of nutrients, the dominance of reduction processes over oxidation ones. Irrigation of rice crops using drip irrigation also causes changes in salt and water-air regimes, which leads to the formation of salt bags and toxic salinization of the soil in a layer of 0-60 cm. The negative effect of drip irrigation is not so noticeable compared to flooding conditions and can be eliminated by observing crop rotation with the rate of the main crop not more than 50%. The research was conducted during 2016-2020 in the territory of the Rice Institute of NAAS and its experimental farm (Skadovsk district, Kherson region), where the soil cover is represented by dark chestnut saline soil. The study of the effect of rice cultivation in flood conditions was carried out on a rice irrigation system with an area of ​​190 ha, and under drip irrigation - on a demonstration trail with an area of ​​4 ha. The oxidation-reduction status of the arable soil layer of rice crop rotations when rice growing, is seasonal. In the period of water layer maintaining in the field, in the arable layer reduction processes predominate, while after harvesting and checks draining the intensity of the reduction processes is moderate and decreases. A model describing this process by the equation of a quadratic parabola was constructed. Growing rice under drip irrigation also reduces the oxidation-reduction soil capacity to negative values, but for a short period, which does not adversely affect the soil. The dynamics of this indicator in the conditions of drip irrigation is described by the equation of a quadratic parabola. Continuous monitoring of this process enables to evaluate the stability of fluctuations of the oxidation-reduction soil balance, which is important for assessing soil quality.

INFLUENCE OF ALLOYING Ti, Mo AND W ON THE KINETIC AND STRENGTH CHARACTERISTICS OF MEMBRANE ALLOYS BASED ON Nb AND V

Проведен анализ влияния Ti, Mo и W на характер аморфной нано- и кристаллической структуры на прочностные и кинетические характеристики - диффузии D и проницаемости Ф водорода в мембранных сплавах, созданных на основе бинарных Ni - Nb и V - Ni. Легирование сплавов Ni - V титаном, молибденом и вольфрамом ведет к постепенному замещению ими ниобия и ванадия и способствует образованию нескольких второстепенных фаз хотя и действующих как барьеры для диффузии водорода, но способствующих снижению процессов гидридообразования. Выявлена строгая зависимость кинетики водорода не только от термодинамических параметров -температуры и давления, но и от наличия свободного объема в формируемых аморфных, нано-кристаллических и кристаллических сплавов. Установлено, что процессы селективности, динамика водорода - его поток J, определяемый произведением диффузии и проницаемости (J = D×Ф), зависят от базового состава, выбора легирующих элементов (Ti,Mo и W ), а также формируемых структур - аморфной, нанокристаллической и полифазной дуплексной кристаллической микроструктурой. Установлено, что тщательно подобранный состав определяет производительность селективного процесса и способствует выделению высокочистого водорода с последующими его приложениями для зеленой энергетики. An analysis was carried out of influence of Ti, Mo and W on the nature of the amorphous nano- and crystalline structures on the strength and kinetic characteristics - diffusion D and permeability Ф of hydrogen in membrane alloys based on binary Nb - Ni, V - Ni. Doping with Nb - V alloys, titanium, molybdenum and tungsten leads to the gradual replacement of niobium and vanadium, and promotes the formation of several minor phases while acting as barriers for hydrogen diffusion, but contributing hydride reduction processes. A close dependence of the hydrogen kinetics was revealed not only on thermodynamic parameters - temperature and pressure, but also on the presence of free volume in the formed amorphous, nanocrystalline and crystalline alloys. So, the processes of selectivity, the dynamics of hydrogen - its flux J determined by the product of diffusion D and permeability Ф, J = D×Ф depend on the basic composition and the choice of alloying elements (Ti,Mo and W ), as well as the formed structures - amorphous, nanocrystalline and duplex, represented by multiphase crystalline microstructures. It was found that a carefully selected composition determines the productivity of the selective process and promotes the release of high-purity hydrogen with its subsequent applications for green energy.

Biofilm matrix proteome of clinical strain of P. aeruginosa

Extracellular matrix plays a pivotal role in biofilm biology. Despite importance of matrix proteins as potential targets for development of antibacterial therapeutics little is known about matrix proteomes. While P. aeruginosa is one of the most important pathogens with emerging antibiotic resistance only few studies are devoted to matrix proteomes and there are no studies describing matrix proteome for any clinical isolates. As matrix responsible for some extracellular functions, it is expected that protein composition should be different in comparison with embedded in biofilm cells and this difference reflects possible active processes in matrix. Here we report the first matrix proteome for clinical isolate of P. aeruginosa in comparison with embedded cells. We have identified the largest number of proteins in matrix among all published studies. Ten proteins were unique for matrix and not present inside cells, but most of these proteins do not have well described function with respect to extracellular component of biofilm. Functional classification of enriched in matrix proteins resulted in several bioprocess groups of proteins. Top three groups were: oxidation-reduction processes, nucleoside metabolism and fatty acid synthesis. Finally, we discuss obtained data in prism of possible directions for antibiofilm therapeutic development.