A study of the antibacterial properties of a non-polar extract of microalgae Chlorella sorokiniana on gram-positive bacteria is presented along with a determination of the minimum inhibitory ...concentrations of the mixture and the individual metabolites that make up the extract. A regular effect of illumination on the intensity of the antibiotic effect of non-polar microalgae extract on gram-positive bacteria is demonstrated. A mixture of substances extracted from disintegrated cells of the microalgae biomass Chlorella sorokiniana has an inhibitory effect on bacterial growth at a photosynthetically active radiation level of 100±6 μmol photons/(m 2 ×s). The minimum effective amount of the extract is 330±11.09 µg. When analysing the chemical structure of the components of the non-polar fraction extracted from the cells of microalgae Chlorella sorokiniana, the composition of the non-polar extract was shown to include triacylglycerides, fatty acids, o-dialkyl monoglycerides and ethers of sterols or waxes, or trialkyl esters of glycerol. When studying the antibiotic properties of individual fractions of substances, triacylglycerides and fatty acids were found to have an antibiotic effect on gram-positive bacteria. In this case, the minimum effective amount of triacylglycerides is 400±13.37 μg, while that of fatty acids is 600±20.05 μg. The combined effect of a mixture of non-polar extract substances gives the most pronounced antibiotic effect on gram-positive bacteria at a photosynthetically active radiation level of 100±6 μmol of photons/(m 2 ×s). Thus, an increase in antibacterial action was demonstrated when using a mixture of substances of the non-polar extract of microalgae Chlorella sorokiniana at a photosynthetically active radiation level of 100±6 μmol of photons/(m 2 ×s).
Methodology of designing flexible chemical engineering processes, apparatuses, and systems, which form prerequisites of efficient process control and automation was proposed, and the multistage ...iteration procedure of solving the problems of the integrated design of flexible automated chemical engineering systems (CESs) was formalized. A method of calculating the structural parameters and regime variables (optimal tasks for the controllers of a system of automatic stabilization (SAS)) that provide the optimal (from the viewpoint of energy- and resource saving and product quality) and safe operation of chemical engineering processes, apparatuses, and systems for the technological equipment implementation of chemical engineering systems has been developed.
A numerical study of the dynamics of pressure swing adsorption process for synthesis gas separation and hydrogen concentration was carried out. The influence of regime parameters (compressor and ...vacuum pump outlet pressures, duration of the "adsorption-desorption" cycle, backflow coefficient) and design parameters (height of the adsorbent bulk layer and the internal bed diameter) on the recovery and purity of hydrogen, plant performance in a given range of changes in the temperature, composition and pressure of the initial gas mixture was studied. It is found that when the hydrogen content decreases from 68 to 48 vol. % and a simultaneous increase in the carbon dioxide content in the initial gas mixture from 27 to 47 vol. % required hydrogen purity value at 99.99 vol. % can be achieved by reducing the pressure at the outlet of the vacuum pump from 0.75?105 to 0.5?105 Pa. At the same time, the duration of the adsorption stage increases from 120 to 150 seconds, and the degree of hydrogen extraction decreases from 55 to 52% due to an increase in the proportion of the flow selected for the regeneration of the adsorbent. Increasing the temperature of the initial gas mixture from 293 to 323 K leads to the need to reduce the duration of the adsorption stage from 148 to 42 s due to a decrease in the equilibrium concentrations of carbon dioxide and monoxide in the adsorbent.
The work is devoted to the study of technological processes corresponding to the requirements of the developing closed-loop economy, which will be based on the wide use of renewable resources, ...maximum recycling of secondary raw materials, with the transition from fossil fuels to renewable energy sources as one of the objectives. A study of the possibility of producing fatty acid esters from renewable raw materials of plant origin - microalgae Chlorella vulgaris - with the use of municipal wastewater was carried out. Approaches to the development of technologies of fatty acid esters production and promising ways to improve the key stages of such production are considered. It is shown that under certain conditions (temperature of 10-32 °С, illumination of 7-14 klx) municipal wastewater can be treated and at the same time serve as a nutrient medium in the process of cultivation of microalgae biomass with lipid content of 10-18% of dry matter. Depending on the conditions of cultivation, the cells of the Chlorella vulgaris IPPAS C-2 strain of microalgae reduce the concentration of ammonium cations, phosphate anions and total microbial number in municipal wastewater by 93 - 95% (wt.), 90 - 97% (wt.) and 86 - 95%, respectively. The influence of technological conditions of the process on the biomass growth rate and fatty acid composition of accumulated lipids is analyzed. It is experimentally established that triglycerides, O-dialkylmonoglycerides and fatty acids have the greatest inhibiting effect on the microflora of wastewater. Using Hansen solubility parameters, a system of polar and non-polar solvents consisting of ethanol and petroleum ether in the ratio of 1:2 (vol). was selected, which ensures the efficient conduct of the extraction process. The yield of fatty acid esters of КFAE = 45% was obtained in the course of transesterification reaction with the use of ethanol in the ratio with lipids 6:1 (mole) at the reaction temperature of 60 °C in the presence of an alkaline catalyst - sodium hydroxide (3% of the mass of lipids).
Numerical researches of influence of temperature, composition and pressure changes of the initial gas mixture on the purity, recovery and capacity of the pressure swing adsorption (PSA) unit was ...made. Air separation dynamics was researches in a wide range of control (pressure at the compressor outlet, the duration of the adsorption – desorption cycle, backflow coefficient, programs of control valves opening degree in time) variables. It was found that the change of regime parameters and the inflow on has a significant impact on the purity and recovery of oxygen. Also was founded that the range of the duration of the adsorption stage and the compressor outlet pressure values should be limited to the intervals of 39-43 s and 2.7–2.8?105 Pa, respectively. The steady-state of the PSA unit mode output time was amount 20-30 cycles of "adsorption-desorption". Formulated and solved the optimization tasks of regime parameters of air separation cyclic processes by criterion of maximum oxygen recovery in 2-bed PSA unit with granular adsorbent zeolite 13X; the optimal values of the control parameters for differential environmental conditions (when the product oxygen concentration not less than 45% vol. and the PSA unit capacity ~2 l/min) are determined. It is shown that the implementation of the optimal of the inlet and discharge valves opening degree changes program in PSA unit allows to provide the set values of the gas flow rate in the "frontal" layer of the adsorbent, in which there is no abrasion of the adsorbent in the cyclic adsorption–desorption processes
We investigate the magnetotransport properties of strained 80 nm thick HgTe layers featuring a high mobility of μ ∼ 4 × 10(5) cm(2)/V · s. By means of a top gate, the Fermi energy is tuned from the ...valence band through the Dirac-type surface states into the conduction band. Magnetotransport measurements allow us to disentangle the different contributions of conduction band electrons, holes, and Dirac electrons to the conductivity. The results are in line with previous claims that strained HgTe is a topological insulator with a bulk gap of ≈ 15 meV and gapless surface states.
The Iceland scallop from the Barents Sea is a commercially important species with promising aquaculture potential, but information on the biochemical properties of its tissues is limited. Our ...analysis of the adductor muscle, gonad, and mantle of this bivalve mollusk from coastal waters provided insight into its amino acid composition. Biochemical analysis revealed predominant levels of glycine (11.8, 11.5, and 9.6 mg g
, respectively) and arginine (11.2, 8.3, and 5.8 mg g
, respectively). While multivariate comparisons did not reveal significant differences in amino acid composition between the tissues, single comparisons showed significantly higher levels of arginine and leucine in the adductor muscle compared to those of the mantle. The abundant presence of glycine and arginine underscores their importance in maintaining basic physiological processes, consistent with other scallop species. Redundancy analysis identified water depth and scallop gonad index as influential factors shaping the amino acid profile in the adductor muscle. In the case of the mantle, water temperature emerged as the main driver of amino acid content. Our results confirm the richness of essential amino acids in scallop by-products and highlight their potential for human consumption, production of feed ingredients for farmed animals, and nutraceuticals.
Recent topological band theory distinguishes electronic band insulators with respect to various symmetries and topological invariants, most commonly, the time reversal symmetry and the Z_{2} ...invariant. The interface of two topologically distinct insulators hosts a unique class of electronic states-the helical states, which shortcut the gapped bulk and exhibit spin-momentum locking. The magic and so far elusive property of the helical electrons, known as topological protection, prevents them from coherent backscattering as long as the underlying symmetry is preserved. Here we present an experiment that brings to light the strength of topological protection in one-dimensional helical edge states of a Z_{2} quantum spin-Hall insulator in HgTe. At low temperatures, we observe the dramatic impact of a tiny magnetic field, which results in an exponential increase of the resistance accompanied by giant mesoscopic fluctuations and a gap opening. This textbook Anderson localization scenario emerges only upon the time-reversal symmetry breaking, bringing the first direct evidence of the topological protection strength in helical edge states.
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