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  • Author or Editor: B. Gabriela x
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Authors: Loredana Feher, B. Jurconi, Gabriela Vlase, T. Vlase and N. Doca

Abstract  

The thermooxidative degradation of three models of oily soils was studied under non-isothermal conditions, at heating rates of 5, 10, 15 and 20�C min−1. Di-octyl-sebacate, as model for synthetic oil, was adsorbed on silica, alumina and silico-alumina, considered models for the inorganic micelle of a soil. For a kinetic analysis, the TG data were processed by three methods: Flynn-Wall-Ozawa, Friedman and NPK (Nomen-Sempere). The results indicate the NPK as the less speculative method that allows a separation of the elementary steps and at the same time a separation of the temperature, respective conversion dependent part of the reaction rate.

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Abstract  

Thermal analysis is one of the most widely used methods for studying the solid state of pharmaceutical substances. TG/DTG and DSC curves provide important information regarding the physical properties of the pharmaceutical compounds (stability, compatibility, polymorphism, kinetic analysis, phase transitions etc.). The purpose of a kinetic investigation is to calculate the kinetic parameters and the kinetic model for the studied process. The results are further used to predict the system’s behaviour in various circumstances. A kinetic study regarding the diazepam, nitrazepam and oxazepam thermal decomposition was performed, under non-isothermal and isothermal conditions and in a nitrogen atmosphere, for the temperature steps: 483, 498, 523, 538 and 553 K. The TG/DTG data were processed by three methods: isothermal model-fitting, Friedman’s isothermal-isoconversional and Nomen-Sempere non-parametric kinetics. In the model-fitting methods the kinetic triplets (f(α), A and E a) that defines a single reaction step resulted in being at variance with the multi-step nature of diazepines decomposition. The model-free approach represented by isothermal and non-isothermal isoconversional methods, gave dependences of the activation energies on the extent of conversion. It is very difficult to obtain an accord with the similar data which resulted under non-isothermal conditions from a previous work. The careful treatment of the kinetic parameters obtained in different thermal conditions was confirmed to be necessary, as well as a different strategy of experimental data processing.

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Abstract

In this paper presents ternary diagrams for geothermal waters from two wells in Săcuieni: ternary diagram Na-K-Mg, ternary diagram Cl-SO4-HCO3 and calculation model, which allows location of geothermal fluids in these diagrams. Classification of geothermal water with the two diagrams, involving knowledge of their chemical composition. Thus, it was the chemical composition of geothermal water coming from drillings: 1704 Săcuieni and 752 Săcuieni, situated in Bihor county. Location of geothermal water on the two diagrams we will establish the type of water, depending to the presence in their content of major anions and cations, what is of great importance for use in various purposes of the geothermal fluids.

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Authors: J. Staszkiewicz, M. Skowronski, Gabriela Siawrys, T. Kaminski, B. Krazinski, K. Plonka, B. Wylot, Jadwiga Przala and S. Okrasa

The objective of the study was to examine the expression of the genes coding for proopiomelanocortin (POMC), proenkephalin (PENK) and prodynorphin (PDYN) in porcine luteal cells isolated from corpora lutea (CL) collected on days 3–6, 8–10 and 13–16 of the oestrous cycle. Total RNA was purified from non-incubated cells and from cells incubated for 48 h in the absence or presence of luteinising hormone (LH). The semi-quantitative RT-PCR technique, involving coamplification of the target and control cDNA (β-actin or 18S rRNA), was used to examine gene expression. It was found that the genes coding for opioid precursors are expressed in both non-incubated and incubated porcine luteal cells representing the early, mid- and late luteal phase. In non-incubated cells, only POMC mRNA content changed during CL development, whereas the expression of PENK and PDYN genes remained relatively constant. Additionally, the treatment of cells with LH markedly affected the expression of POMC and PENK, but no influence on PDYN expression was observed. The present study indicates that porcine luteal cells may produce opioid peptides and that gene expression of their precursors (except for PDYN) may be modulated in these cells by LH. Moreover, the present results support the involvement of opioid peptides in local regulation within the CL of the pig.

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