The importance and advantages of the hybrid approach developed within the TAIGA project for studying the high-energy section of the spectrum of gamma radiation in the Universe are discussed. The ...pilot complex of the TAIGA gamma observatory with an area of 1 km
is briefly described along with the lines of its development, and the first results obtained on this basis are given.
Bioprosthetic heart valves (BHVs) are known for their lower thrombogenicity rates and excellent hemodynamic parameters similar to native valves. However, the lifespan of these medical devices is ...limited to 15 years due to the structural valve degeneration. One of the mechanisms underlying functional impairment and calcification of BHVs includes proteolytic degradation of biomaterials. However, proteases found in xenogeneic BHVs tissue remain poorly studied. In this study using the dot blot assay, we have performed a screening analysis of proteolytic enzymes and their inhibitors in the leaflets of five BHVs explanted due to their dysfunction. Five aortic valves (AVs) explanted due to calcific aortic valve disease were studied as a comparison group. The results of the study have demonstrated that at least 17 proteases and 19 of their inhibitors can be found in BHVs. In the AVs 20 proteases and 21 their inhibitors were identified. Small quantitative differences were noted between proteomic profiles of the BHVs and AVs. Matrix metalloproteinases (MMPs) were expressed in BHVs and AVs at comparable levels, but the level of tissue inhibitors of metalloproteinases-1/-2 and RECK protein in implant tissues was lower than in natural valves. Probably, excessive activity of MMPs cannot be counterbalanced by their inhibitors in BHVs and therefore MMPs can degrade prosthetic biomaterial. Moreover, the detection of a wide range of proteolytic enzymes and their inhibitors in the degenerated BHVs suggests the existence of several pathophysiological pathways that can lead to structural valve degeneration.
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Bioprosthetic heart valves (BHVs) have lower thrombogenicity rates and excellent hemodynamic parameters similar to native valves. However, the lifespan of these medical devices is limited to 15 ...years due to the structural valve degeneration (SVD). One of the mechanisms underlying functional impairment and calcification of BHVs includes proteolytic degradation of biomaterials. However, proteases found in xenogeneic tissue of BHVs remain poorly studied. In this study using the dot blot assay, we have performed a screening analysis of proteolytic enzymes and their inhibitors in the leaflets of five BHVs explanted due to dysfunction. Five aortic valves (AVs) explanted due to calcific aortic valve disease were used as a comparison group. The results of the study have demonstrated the presence of at least 17 proteases and 19 of their inhibitors in BHVs. In the AVs 20 proteases and 21 of their inhibitors were identified. Small quantitative differences were found between proteomic profiles of BHVs and AVs. Matrix metalloproteinases (MMPs) were expressed in BHVs and AVs at comparable levels, but the level of tissue inhibitors of metalloproteinases-1/-2 and reversion-inducing-cysteine-rich protein with Kazal motifs in implant tissues was lower than in native valves. This suggests that excessive activity of MMPs cannot be counterbalanced by their specific inhibitors in BHVs and therefore MMPs initiate the process of degeneration. Moreover, the detection of a wide range of proteolytic enzymes and their inhibitors in the degenerated BHVs suggests the existence of several pathophysiological pathways that can lead to SVD.
Method of burning the molybdenite concentrates Ovtsyn, D. V.; Kostyunin, V. V.; Potapov, V. N. ...
Russian journal of non-ferrous metals,
06/2009, Letnik:
50, Številka:
3
Journal Article
Recenzirano
A new method of burning the molybdenite concentrate is developed. An installation is used in which material is burned in the vortical flow of the oxidizer with obtaining the cinder. It is established ...that, at a temperature of 600°C and air consumption of 100–120 m 3 /h, 98.7% of MoS
2
transforms into MoO
3
and 85% of Re sublimes in 0.5 h. The sulfur content in the cinder is <1.8%. Upon treating the cinder with a potassium carbonate solution, up to 96.5% Mo is extracted. This method provides a rather high productivity, it is rather simple, it does not require large expenses for equipment and exploitation, it is promising, and it can be used for burning other materials containing sulfides of metals.
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