Капитальный ремонт магистрального газопровода «НГПЗ – Парабель» на участке 227-254 км

Объектом исследования является магистральный газопровод Ду 1000 протяженностью 26,267км. Цель работы – выбор эффективного способа выполнения работ по капитальному ремонту магистрального газопровода. Проведены расчеты толщины стенки трубы, трубопровод на прочность и устойчивость. Рассмотрена разработка траншеи, сварочно-монтажные работы, прокладка, ликвидации разрывов, проведение испытания, мероприятия по охране труда и безопасности строительства, охране окружающей среды, технико-экономическая часть. Было предложено выполнять укладку нового трубопровода параллельно существующему, силами КТП. На основании выполненных расчетов на прочность было рекомендовано увеличения толщины стенки.The object of study is (are) the main gas pipeline DN 1000 with a length of 26,267 km. Purpose – the choice of effective method of execution of works on capital repair of the trunk gas pipeline. The calculations of wall thickness, tubing for strength and stability. Describes the development of a trench, welding and installation works, laying, bridging the gaps, running the test, measures on labor protection and building safety, environmental, technical and economic part. It was proposed to carry out laying a new pipeline parallel to the existing, by the CTU. On the basis of the calculations for strength, it was recommended that increasing the thickness of the wall

LRAT Overexpression Diminishes Intracellular Levels of Biologically Active Retinoids and Reduces Retinoid Antitumor Efficacy in the Murine Melanoma B16F10 Cell Line

BACKGROUND/AIM Vitamin A (all- trans -retinol, ATRol) serves as a precursor for all- trans -retinoic acid (ATRA), a ligand for the retinoic acid receptor (RAR), representing a potent regulator for many physiological processes. While murine melanoma cells are highly sensitive to retinoid treatment, human melanoma cells have developed still unidentified mechanisms that mediate cellular retinoid resistance. One of the key retinoid metabolizing enzymes is lecithin retinol acyltransferase (LRAT), which catalyzes the transformation of ATRol into inactive retinyl esters. LRAT is highly expressed in human melanoma cells. The aim of this study was to identify the mechanisms in retinol metabolism that are responsible for cellular retinoid sensitivity in the murine melanoma cell line B16F10. METHODS mRNA expression analysis, cell viability assessment and determination of intracellular retinoid levels using HPLC analysis of a generated LRAT-overexpressing B16F10 cell line compared to the control B16F10 cell line. RESULTS We found that the murine retinoid-sensitive B16F10 cell line does not express the enzyme LRAT. LRAT overexpression decreased the antiproliferative effects of retinoid treatment in these melanoma cells. The RAR-regulated enzyme Cyp26a1 showed a significantly lower expression in LRAT-overexpressing B16F10 cells. Cyp26a1 expression was restored after ATRA incubation. HPLC analysis revealed that the level of inactive retinyl ester increased after ATRol treatment, and levels of the substrate ATRol and biologically active ATRA significantly decreased in LRAT-overexpressing murine melanoma. Consistently with this, levels of 4-oxoretinoic acid, an ATRA metabolite and Cyp26a1 product, were also decreased in LRAT-overexpressing cells. CONCLUSION Our results revealed a direct link between LRAT expression and regulation of ATRA levels indicating that the absence of LRAT-catalyzed retinol esterification is important for mediating retinoid sensitivity in murine melanoma cells. Thus, our data suggest that LRAT overexpression represents a novel mechanism by which tumor cells can escape high supplementary ATRA levels that mediate tumor-suppressive RAR signaling