RETENTION AND LIPOPHILICITY OF ESTRADIOL DERIVATIVES IN NORMAL- AND REVERSED-PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

The retention behaviour and separation ability of some estradiol derivatives were studied by HPLC on silica and C-18 commercially available columns. The mobile phases used were: benzene-ethyl acetate, benzene-tetrahydrofuran, benzene-acetonitrile, isopropanol-water and tetrahydrofuran-water in various proportions. The results are discussed in terms of nature of the solute, eluent and stationary phase. Correlation between the retention constants of estradiol derivatives obtained on C-18 column and log P calculated by program ACD log P was examined too

INTERACTION OF THE WAVE PACKET AND GRAPHENE SHEET AND CRITICAL TEMPERATURE OF HYDROGEN STORAGE

Concerning to their industrial application, testing of the performances of nanomaterials is very important . Research of graphene characteristics is important for the storage of hydrogen. In this paper the interaction of the wave packet was simulated with one graphene sheet and the results were studied. Temperature Tf was calculated, whereby, for T ≤ Tf, the graphene sheet can significantly affect the movement of a wave packet, while the movement of the wave packet is not significantly affected for T> Tf. We analyzed the functional dependence of temperature Tf on the sheet shapes and sizes. The question under which conditions the temperature Tf is suitable for significant hydrogen storage is a very interesting issue. Approximate quantum Newton's equation was used for calculation. Guisbiers and Buchaillot discussed the dependence of the size and shape of nanostructures (graphene sheet) and characteristic temperatures of transition. The results obtained by computer experiments partly agree with the equation proposed by Guisbiers and Buchaillot. The computations were done using Runge-Kutta-Fehlberg method and partly agree with equation. Guisbiers and Buchaillot discussed the dependence of nanostructure size and shape (graphene sheet) and characteristic temperature (phase) transition, suggesting a universal equation, in which case our results can be fitted with a curve of this form for certain temperature intervals.Concerning to their industrial application, testing of the performances of nanomaterials is very important . Research of graphene characteristics is important for the storage of hydrogen. In this paper the interaction of the wave packet was simulated with one graphene sheet and the results were studied. Temperature Tf was calculated, whereby, for T ≤ Tf, the graphene sheet can significantly affect the movement of a wave packet, while the movement of the wave packet is not significantly affected for T> Tf. We analyzed the functional dependence of temperature Tf on the sheet shapes and sizes. The question under which conditions the temperature Tf is suitable for significant hydrogen storage is a very interesting issue. Approximate quantum Newton's equation was used for calculation. Guisbiers and Buchaillot discussed the dependence of the size and shape of nanostructures (graphene sheet) and characteristic temperatures of transition. The results obtained by computer experiments partly agree with the equation proposed by Guisbiers and Buchaillot. The computations were done using Runge-Kutta-Fehlberg method and partly agree with equation. Guisbiers and Buchaillot discussed the dependence of nanostructure size and shape (graphene sheet) and characteristic temperature (phase) transition, suggesting a universal equation, in which case our results can be fitted with a curve of this form for certain temperature intervals

Influence of the applied pressure of processing upon bioactive components of diets made of feathers

The feathers gained by slaughtering fattening chickens can be processed into protein meal for feeding certain animals, as indicated by its chemical characteristics. However, raw feather proteins (keratin) are faintly digestible (cca. 19%), even inert in digestive tract. Digestion of feather proteins could be improved by hydrolysis (alkaline, enzymatic, microbiological or hydrothermal). Practically, hydrothermal processing of raw feathers is mostly applied. The influence of hydrothermal processing under the pressures of 3.0, 3.5 or 4.0 bar on the nutritive value of the resulting meal is presented in this paper. For the hydrolysis of raw feathers, semi continuous procedure was applied. Semi continuous procedure of feathers processing comprise hydrolysis of raw wet feathers followed by partial drying of hydrolyzed mass that has to be done in a hydrolyser with indirect heating. Continuous tubular dryer with recycled air was used during the final process of drying. Protein nitrogen decreased by 3.46% and 4.80% in comparison with total protein nitrogen content in raw feathers under the pressure of 3.0 and 3.5 bar, respectively. The highest applied hydrolysis pressure caused the greatest loss of protein nitrogen up to 9.52%. Hydrothermal hydrolysis under pressure has increased in vitro protein digestibility significantly. Under pressure of 3.0, 3.5 and 4.0 bar digestibility of proteins increasing from 19.01 to 76.39, 81.71 and 87.03%, respectively. Under pressure of 3.0, 3.5 and 4.0 bar cysteine content decreased from 6.44 to 4.17% (loss 35.25%), 3.94 (loss 38.825%) and to 3.75% (loss 41.77%), respectively. These decreases are statistically significant. It can be concluded that the hydrolysis carried out under the pressure of 3.5 bar, during the period of 25 min, and with the content of water in raw feathers of cca. 61% is the optimal technological process for converting raw feathers into diets for certain animal diets

Experimental study and analytical model of shear thinning in 3d bioprinting of gelatin

© 2020 Published by Faculty of Engineering. This paper presented extrusion-based 3D bioprinting of gelatin hydrogel and optimisation of material properties and process parameters, in order to improve printability of hydrogel. Gelatin hydrogel was prepared by mixing it with water in concentration of 13.04 wt%. Dimensional accuracy of the bioprinting was studied and significant changes in comparison with designed geometry were noted. Gelatin hydrogel made only with water showed inadequate thixotropy for extrusion based bioprinting and poor mechanical properties of the printed sample, and needs additional constituents to enable good printability with satisfying dimensional accuracy. We presented parameter optimisation index (POI), shear thinning model and friction factor of gelatin hydrogel by using analytical approach. Friction factor of the gelatin hydrogel during bioprinting was 0.268 10-5. Analytical models of shear thinning and friction factor were in consistence with experimental data, and indicated that such approach can be used in optimisation of bioprinting parameters and material properties

Tehnološki postupak iskorišćenja karbotacionog mulja otpada iz procesa proizvodnje šećera kao katalizatora u proizvodnji biodizela

Registrovan patent na nacionalnom nivou. Rešenje o priznatom patentu 990, broj: 2021/11636–П–2019/0713 od 28.09.2021. godine. Prethodno prihvaćeno kao tehnološko rešenje 30.07.2020. od strane MNO za biotehnologiju i poljoprivredu, korisnik Vladimir Kovač iz Novog Sada