Особенности дуговой сварки вертикальных швов резервуара

Цель работы – расчет режимов сварки и выбор сварочных материалов для получения равнопрочного коррозионностойкого соединения. Сложность изготовления стенок резервуара состоит в том, что резервуар РВС предназначен работать в агрессивной среде и должен выдерживать большое давление и нагрузку на свои основные части. При выборе стали необходимо руководствоваться основными её характеристиками - минимальным пределом текучести, толщиной проката и ударной вязкости.The aim of this work is the calculation of the modes of welding and selection of welding materials to obtain a durable corrosion-resistant connection

Molecular MRI of early thrombus formation using a bimodal alpha2-antiplasmin-based contrast agent

Objectives: We aimed to investigate whether early thrombus formation can be visualized with in vivo magnetic resonance imaging (MRI) by the use of a novel bimodal a2-antiplasmin-based contrast agent (CA). Background: Thrombus formation plays a central role in several vascular diseases. During the early phases of thrombus formation, activated factor XIII (FXIIIa) covalently cross-links a2-antiplasmin to fibrin, indicating the potential of a2-antiplasmin-based CAs in the detection of early thrombus formation. Methods: A bimodal CA was synthesized by coupling gadolinium-diethylene triamine pentaacetic acid and rhodamine to an a2-antiplasmin-based peptide. For the control CA, a glutamine residue essential for cross-linking was replaced by alanine. In vitro-generated thrombi were exposed to both CAs and imaged by MRI and 2-photon laser-scanning microscopy. Immunohistochemistry was performed on human pulmonary thromboemboli sections to determine the presence of a2-antiplasmin and FXIII in different thrombus remodeling phases. In vivo feasibility of the CA in detecting early thrombus formation specifically was investigated with MRI. Results: In vitro-generated thrombi exposed to the a2-antiplasmin-based CA showed hyperintense magnetic resonance signal intensities at the thrombus edge. No hyperintense signal was observed when we used the a2-antiplasmin-based CA in the presence of FXIII inhibitor dansylcadaverine nor when we used the control CA. Two-photon laser-scanning microscopy demonstrated that the a2-antiplasmin-based CA bound to fibrin. Immunohistochemistry demonstrated substantial a2-antiplasmin staining in fresh compared with lytic and organized thrombi. The administration of CA in vivo within seconds after inducing thrombus formation increased contrast-to-noise ratios (CNRs 2.28 ± 0.39, n=6) at the site of thrombus formation compared with the control CA (CNRs -0.14 ± 0.55, p = 0.003, n = 6) and a2-antiplasmin-based CA administration 24 to 48 h after thrombus formation (CNRs 0.11 ± 0.23, p = 0.006, n = 6). Conclusions: A bimodal CA was developed, characterized, and validated. Our results showed that this bimodal CA enabled noninvasive in vivo magnetic resonance visualization of early thrombus formation. © 2009 American College of Cardiology Foundation

Sodium arsenite reduces severity of dextran sulfate sodium-induced ulcerative colitis in rats

The histopathological features and the associated clinical findings of ulcerative colitis (UC) are due to persistent inflammatory response in the colon mucosa. Interventions that suppress this response benefit UC patients. We tested whether sodium arsenite (SA) benefits rats with dextran sulfate sodium (DSS)-colitis. The DSS-colitis was induced by 5% DSS in drinking water. SA (10 mg/kg; intraperitoneally) was given 8 h before DSS treatment and then every 48 h for 3 cycles of 7, 14 or 21 d. At the end of each cycle rats were sacrificed and colon sections processed for histological examination. DSS induced diarrhea, loose stools, hemoccult positive stools, gross bleeding, loss of body weight, loss of epithelium, crypt damage, depletion of goblet cells and infiltration of inflammatory cells. The severity of these changes increased in the order of Cycles 1, 2 and 3. Treatment of rats with SA significantly reduced this severity and improved the weight gain