No abstract

Our aim was to study the selected cases of the patients with ischemic heart disease and to analyze the structure of blood serum of patients in comparison with control serum of healthy subjects by methods: synchronous fluorescence fingerprint and atomic force microscopy that are still not used in clinical practice. Our results of fluorescence analysis showed that blood serum of all patients with ischemic heart disease decreased intensity of fluorescence in comparison with control blood serum. Endogenous fluorescence of synchronous fluorescence fingerprint of blood serum of patients with unstable angina pectoris state after non ST elevation myocardial infarction; angina pectoris and arterial hypertension 3 was similar, but atomic force microscopy revealed differences in the structure of blood serum of patients with the angina pectoris. Blood serum of patients with angina pectoris exhibited disappearance of fluorescence peak with maximum fluorescence and showed lower fluorescence intensity than control blood serum and blood serum of patients with arterial hypertension 2. Profiles of synchronous fluorescence fingerprint of blood serum of patients with arterial hypertension stage 2 showed formation of the new fluorescent peak with maximum fluorescence, similar shape of synchronous fluorescence fingerprint and higher fluorescence intensity than blood serum of healthy subjects. Blood serum sensitively revealed changes in the body by using untraditional novel techniques which enable the analysis of the mixture of blood serum and might be a new possibility in study of heart ischemia diseases.

We prepared Pt3Ni and PtNi3 nanoparticles of various sizes on conductive and atomically smooth highly oriented pyrolytic graphite surfaces using potentiostatic electrodeposition. We can control the size of electrodeposited nanoparticles and their density on the surface by changing the deposition time. The morphology of nanoparticles was determined by scanning electron microscopy. PtNi3 particles have spherical shape, while Pt3Ni particles have more irregular shape. Composition of particles was confirmed by energy dispersive spectroscopy. We have measured magnetic properties of both systems with 100 s preparation time, superparamagnetic behavior was observed in PtNi3 nanoparticles with blocking temperature TB = 225 K.

We studied degradation mechanism of platinum catalysts films of ultralow loading on titanium nitride, highly oriented pyrolytic graphite and Sigradur G glassy carbon substrates. The films were prepared by magnetron sputtering with platinum amount nominally corresponding to 1, 5 and 10 layers. The catalyst stability was tested by potential cycling in perchloric acid. We find that dependence of catalyst stability on the substrate type is very much function of catalyst loading. This is a result of different catalyst degradation mechanisms. For samples with 1 platinum layer we observe that three dimensional crystallites are formed from two dimensional initial nanoislands and degradation mechanism follows power laws derived for three dimensional nanoparticle growth; for samples with 5 platinum layers we observe formation of interconnected network of two dimensional islands. The electrochemical surface area loss does not depend much on the substrate type and the degradation mechanism follows power law developed for two dimensional particle growth. Catalyst films made by deposition of 10 platinum layers are continuous films on all three studied substrates and after potential cycling, the films stay continuous with small difference of the film stability for studied substrates. For studied platinum loadings carbon substrates performed better than titanium nitride substrate.