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  • Author or Editor: M. Zeman x
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Experimental and clinical studies have shown alterations in activity of systems responsible for neuroendocrine stress response in obese individuals. Therefore we investigated the effect of palatable normocaloric liquid nutrition (Fresubin) on alterations in activity of the hypothalamic-pituitary-adrenal (HPA) axis in male Wistar rats of different developmental stages. Control rats (CON) received standard pellet chow all the time from weaning (21st day of age) to 150 days. Fresubin was administered throughout the experiment (LN), only in juvenility (from 21st to 90th day of age; LNJ) or only in adulthood (from 90th to 150th day of age; LNA). Body weight and energy intake were periodically monitored. Adrenal gland and fat tissue weight and plasma corticosterone levels (CORT) was determined after sacrification. Fresubin intake induced obesity in LN and LNA rats. In LN and LNA rats were observed elevated serum CORT levels, but only in LN rats with significant twofold increase compared to LNJ rats. However, the weight of adrenal glands did not differ between LN, LNJ and LNA experimental groups. Based on our results, we suggest, that obesity induced by Fresubin in LN and LNA rats is accompanied by increased HPA activity represented by elevated plasma CORT levels in these rats.

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The renin—angiotensin system (RAS) plays an important role in the development of hypertension and has serious consequences on behaviour. The aim of our study was to investigate the effect of hypertension, induced by up-regulated RAS, on the exploration, anxiety-related behaviour and object recognition in laboratory rats. In the experiment, 12 weeks old normotensive Sprague-Dawley (SD) and hypertensive TGR(mREN2)27 (TGR) male rats with up-regulated RAS were used. In the open-field test, the TGR rats were less active in ambulating, rearing and sniffing and more active in self-grooming and urinating than SD ones. In the elevated plus-maze test, the TGR rats showed lower frequency of total arm entries, closed arm entries and higher frequency of defecation than in controls. In the emergence test, TGR rats did not show significant differences. In the novel object recognition task, the TGR rats spent less time with exploration of both familiar and unfamiliar objects but preferred the novel object over the familiar one and exhibited higher percentage of the total exploring time spent with novel object exploration than SD rats. Our results indicate that the TGR rats are less actively exploring, show some modifications of emotional/anxiety-related behavior and exhibited better recognition abilities.

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Abstract  

TNAZ (1,3,3-trinitroazetidine) is a relatively new, powerful, steam castable, strained ring explosive. Owing these characteristics it is of considerable interest to the energetic material community. A relatively high vapour pressure, volume contraction and formation of shrinkage cavities in the solidification of its melt may be considered as some of its disadvantages. The kinetics and heats of TNAZ sublimation and evaporation were studied by the non-isothermal and isothermal thermogravimetry method. The activation energy of 94-102 kJ mol-1 was found for TNAZ sublimation, while the activation energy of 60-81 kJ mol-1 was found for TNAZ evaporation. The enthalpy of TNAZ sublimation at the melting temperature was found to be 95 kJ mol-1, and the enthalpy of TNAZ evaporation equals 66 kJ mol-1.

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Abstract  

The method of monitoring of U, Pu and some fission products (103,106Ru,134,137Cs and141,144Ce) in gaseous CO2 coolant is described. The method is based on the retention of the radionuclides studied by membrane filters built in by-pass of the burst-cartridge detection (BCD) system. The purpose of the present study was the determination of U, Pu in CO2 and the verification of the possibility of the indirect monitoring of U and Pu contents in the coolant, using the gamma-spectrometric determination of selected fission products retained by the filter. For calibration of the proposed method after decomposition of the filters, uranium was determined spectrophotometrically using Arsenazo III, plutonium was determined radiometrically after its separation by extraction with 2-thenoyltrifluoracetone and the fission products were determined by gamma-spectrometry. From the results obtained it follows that a correlation exists between the U and Pu content in the coolant and the activity of certain fission products retained on the filter.

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