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101.
Melts of pipe steel (strength class K52) obtained at the casting and rolling complex of AO OMK (a branch of AO OMK-Stal’) are analyzed. The initial data correspond to a set of 30 melts. The production system includes batch preparation, steel production in an arc furnace, treatment in a ladle–furnace unit, vacuum treatment (with microalloying and modification), hot rolling, and cutting of the rolled steel into sheet and strip. The basic factors affecting steel quality are identified. The rejection of the steel produced is mainly due to brittle and undeformable nonmetallic silicate inclusions. Changes in the process so as to reduce the content of nonmetallic silicate inclusions are recommended.  相似文献   
102.
Crohn’s disease remains one of the challenging problems of modern medicine, and the development of new and effective and safer treatments against it is a dynamic field of research. To make such developments possible, it is important to understand the pathologic processes underlying the onset and progression of Crohn’s disease at the molecular and cellular levels. During the recent years, the involvement of mitochondrial dysfunction and associated chronic inflammation in these processes became evident. In this review, we discuss the published works on pathogenetic models of Crohn’s disease. These models make studying the role of mitochondrial dysfunction in the disease pathogenesis possible and advances the development of novel therapies.  相似文献   
103.
Aging is one of the most intriguing processes of human ontogenesis. It is associated with the development of a wide variety of diseases affecting all organs and their systems. The victory over aging is the most desired goal of scientists; however, it is hardly achievable in the foreseeable future due to the complexity and ambiguity of the process itself. All body systems age, lose their performance, and structural disorders accumulate. The cardiovascular system is no exception. And it is cardiovascular diseases that occupy a leading position as a cause of death, especially among the elderly. The aging of the cardiovascular system is well described from a mechanical point of view. Moreover, it is known that at the cellular level, a huge number of mechanisms are involved in this process, from mitochondrial dysfunction to inflammation. It is on these mechanisms, as well as the potential for taking control of the aging of the cardiovascular system, that we focused on in this review.  相似文献   
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The effects produced in vitro by minocycline (MINO), aminobenzyl penicillin (ABPC) and cefotiam (CTM) on polymorphonuclear leukocytes (PMN) chemotaxis were investigated in this study using the Boyden chamber technique and polarization assay. The following results were obtained: CTM brought about a significant increase of PMN chemotaxis at the therapeutic dose (10, 100 micrograms/ml), MINO reduced PMN chemotaxis significantly at a concentration as low as 1 microgram/ml and ABPC did not influence PMN chemotaxis at concentrations up to 100 micrograms/ml in both methods. Furthermore, using a checkerboard assay, it was shown that CTM worked as a chemokinetic factor.  相似文献   
109.
The author compares the practice of geriatric psychiatry among three countries: Ireland, the United Kingdom and the United States. The two main areas reviewed are how the practice of geriatric psychiatry is done, and the mental health services available in each country, including organizational characteristics. The US is the most entrepreneurial of the three, Britain's greatest strength is the uniformity and comprehensiveness of its services, and Ireland provides an excellent model for nations of comparable size. Considerable change is occurring in all three countries.  相似文献   
110.
The naturally occurring tetrakisphosphate myo-inositol-1,3,4, 6-tetrakisphosphate [Ins(1,3,4,6)P4] was able to release Ca2+ from the intracellular stores of permeabilized rabbit platelets but was 40-fold less potent than D-myo-inositol-1,4,5-trisphosphate [Ins(1,4,5)P3]. The Ca2+ releasing activity of Ins(1,3,4,6)P4 was rationalized by envisaging two alternative receptor binding orientations in which the vicinal D-1,6-bisphosphate of Ins(1,3,4,6)P4 mimics the D-4,5-bisphosphate in the Ins(1,4,5)P3 binding conformation. This rationalization predicted that Ins(1,4,5)P3 regioisomers [i.e, D-myo-inositol -1,4,6-trisphosphate [D-Ins(1,4,6)P3] and D-myo-inositol-1,3,6 -trisphosphate [D-Ins(1,3,6)P3]] should also possess Ca(2+)-releasing activity. The unambiguous total synthesis of the enatiomers of Ins(1,4,6)P3 [i.e., D-Ins(1,4,6)P3 and D-Ins(3,4,6)P3] and the enatiomers of Ins(1,3,4)P3 [i.e., D-Ins(1,3,6)P3 and D-Ins(1,3,4)P3] allowed an examination of this prediction. D-Ins(1,4,6)P3 released Ca2+ from the intracellular stores of permeabilized platelets and was only 2-3-fold less potent than Ins(1,4,5)P3. D-Ins(1,3,6)P3 [alternative nomenclature, L-Ins(1,3,4)P3] also released Ca2+ but was 12-fold less potent than Ins(1,4,5)P3. Both D-Ins(1,4,6)P3 and D-Ins(1,3,6)P3 displaced specifically bound [3H]Ins(1,4,5)P3 from the Ins(1,4,5)P3 receptor on rat cerebellar membranes. In contrast, however, D-Ins(3,4,6)P3 [alternative nomenclature, L-Ins(1,4,6)P3] and D-Ins(1,3,4)P3 neither possessed Ca(2+)-releasing activity nor displaced [3H]Ins(1,4,5)P3. The ability of D-Ins(1,3,6)P3 to release Ca2+ in permeabilized platelets is in contrast to its apparent lack of Ca(2+)-mobilizing activity previously reported in rat basophilic leukemic cells. The possibility that this is a reflection of the different Ins(1,4,5)P3 receptor subtypes possessed by these two cell types is discussed.  相似文献   
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