Metalloporphyrin intercalation in liposome membranes: ESR study

Liposomes characterized by membranes featuring diverse fluidity (liquid-crystalline and/or gel phase), prepared from egg yolk lecithin (EYL) and dipalmitoylphosphatidylcholine (DPPC), were doped with selected metalloporphyrins and the time-related structural and dynamic changes within the lipid double layer were investigated. Porphyrin complexes of Mg(II), Mn(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and the metal-free base were embedded into the particular liposome systems and tested for 350 h at 24°C using the electron spin resonance (ESR) spin probe technique. 5-DOXYL, 12-DOXYL, and 16-DOXYL stearic acid methyl ester spin labels were applied to explore the interior of the lipid bilayer. Only the 16-DOXYL spin probe detected evident structural changes inside the lipid system due to porphyrin intercalation. Fluidity of the lipid system and the type of the porphyrin complex introduced significantly affected the intermolecular interactions, which in certain cases may result in self-assembly of metalloporphyrin molecules within the liposome membrane, reflected in the presence of new lines in the relevant ESR spectra. The most pronounced time-related effects were demonstrated by the EYL liposomes (liquid-crystalline phase) when doped with Mg and Co porphyrins, whereas practically no spectral changes were revealed for the metal-free base and both the Ni and Zn dopants. ESR spectra of the porphyrin-doped gel phase of DPPC liposomes did not show any extra lines; however, they indicated the formation of a more rigid lipid medium. Electronic configuration of the porphyrin’s metal center appeared crucial to the degree of molecular reorganization within the phospholipid bilayer system

Identification of the heat transfer coefficient in phase change problems

In this paper, an algorithm will be presented that enables solving the two-phase inverse Stefan problem, where the additional information consists of temperature measurements in selected points of the solid phase. The problem consists in the reconstruction of the function describing the heat transfer coefficient, so that the temperature in the given points of the solid phase would differ as little as possible from the predefined values. The featured examples of calculations show a very good approximation of the exact solution and stability of the algorithm

Verification measurements of microclimate in the mines of Katowicki Holding Węglowy S.A. and Kompania Węglowa S.A.

Artykuł poświęcony jest problemowi pomiarów weryfikacyjnych mikroklimatu w kopalniach. Przedstawiono w nim metodykę tego rodzaju badań, opracowaną w ramach realizacji projektu, przeznaczoną do wykorzystania w kopalniach, w których występują trudne warunki mikroklimatu. W dalszej części zaprezentowano wyniki dokonanych pomiarów weryfikacyjnych. Łącznie wykonano 10 serii pomiarowych, podczas których pomiarami objęto 20 różnych stanowisk pracy. Badania potwierdziły występowanie zagrożenia cieplnego w wybranych wyrobiskach podziemnych. Omówiono też wnioski z wywiadu środowiskowego (przeprowadzonego w postaci ankiet), który wykazał m. in., że górnicy często pracują w ciężkich warunkach klimatycznych.The article is devoted to the issue of verification measurements of microclimate in coal mines. It features the methodology of such tests which was elaborated in the course of the project. The methodology had been developed for measurements in selected coal mines with harsh climatic conditions. In the further part of the article the authors presented the results of the conducted verification measurements. In total, there were 10 measurement series carried out on 20 different work stands. The tests confirmed the occurrence of the heat hazard in the selected underground excavations. Additionally, the results of the survey were discussed. The survey, in the form of questionnaires, showed that miners very often work in harsh climatic conditions