18 research outputs found
Сравнительный анализ технологий поддержания пластового давления на нефтяных месторождениях
Объектом исследования является продуктивные пласты нефтяных месторождений. Цель работы - Анализ существующих систем поддержания пластового давления, классификаций систем заводнения, изучение современных технологий в системе ППД. В процессе исследования выполнен сравнительной анализ эффективности систем заводнения на коэффициент нефтеизвлечения. Экономическая эффективность представлена в части "Финансовый менеджмент, ресурсосбережение и ресурсоэффективность".The object of the study is the productive layers of oil deposits. The purpose of the work is to analyze existing systems for maintaining reservoir pressure, classifications of waterflooding systems, and the study of modern technologies in the PAP system. In the course of the research, a comparative analysis of the efficiency of water flooding systems on the oil recovery factor was performed. Economic efficiency is presented in the part "Financial Management, Resource Saving and Resource Efficiency"
Effects of latent TGF-β binding protein (LTBP) on gene expression of transforming growth factor-β (TGF-β) isoforms
Effects of latent TGF-β binding protein (LTBP) on gene expression of transforming growth factor-β (TGF-β) isoforms
Thrombospondin 1 acts as a strong promoter of transforming growth factor β effects via two distinct mechanisms in hepatic stellate cells
Background and aims: Thrombospondin 1 (TSP-1) is an important activator of latent transforming growth factor β (TGF-β) but little is known of the expression patterns and functions of TSP-1 in liver cells. We therefore analysed if and how TSP-1 acts on TGF-β during fibrogenesis. Methods and results: Using reverse transcription-polymerase chain reaction, we demonstrated that hepatocytes from normal liver expressed no TSP-1 mRNA whereas Kupffer cells and sinusoidal endothelial cells did. TSP-1 mRNA and protein were detected in quiescent and activated cultured hepatic stellate cells (HSC) and TSP-1 expression was highly inducible by platelet derived growth factor BB (PDGF-BB) and, to a lesser extent, by tumour necrosis factor α in activated HSC. Furthermore, addition of PDGF-BB directly led to enhanced TGF-β mRNA expression and a TSP-1 dependent increase in TGF-β/Smad signalling. Using either a peptide specifically blocking the interaction of TSP-1 with latent TGF-β or antibodies against TSP-1 not only abrogated activation of latent TGF-β but also reduced the effects of the active dimer itself. Conclusions: Our data suggest that TSP-1 expression is important for TGF-β effects and that it is regulated by the profibrogenic mediator PDGF-BB in HSC. Furthermore, the presence of TSP-1 seems to be a prerequisite for effective signal transduction by active TGF-β not only in rat HSC but also in other cell types such as human dermal fibroblasts