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Separation of Oleic Acid/Stearic Acid Mixtures by Extraction with a Supercritical Solvent The phase balances in the oleic acid/stearic acid/CO2 system show solutropy at pressures up to 600 bar and temperatures between 60 and 100° C in a large area (0.2 to 2.0 weight % referred to the fatty acids). Extraction trials in a split tube column showed in case of loading the CO2 with 1 weight % that at higher relative velocities between gas and liquid phase an enrichment of oleic acid in CO2 even takes place under conditions under which an enrichment of stearic acid should be expected according to the thermodynamic balance. Hence the process of enrichment depends on the velocity of material transfer. The separation effect is a function of the relative velocity of the phases in the column. 相似文献
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GS Kim SH Kim JK Cho JY Park MJ Shin YK Shong KU Lee H Han TG Kim SL Teitelbaum WR Reinus MP Whyte 《Canadian Metallurgical Quarterly》1997,76(3):157-169
Pancreatic cancer is an aggressive disease with a dismal prognosis. It has long been regarded as one of the most difficult cancers to accurately diagnose and stage preoperatively. The purpose of this review is to provide an update of the state-of-the-art for early detection, diagnosis, and staging of pancreatic cancer. These methods include spiral CT scans, magnetic resonance imaging, positron emission tomography (PET) imaging, laparoscopy, endoscopic ultrasound, CA 19-9 serology, fine needle aspiration cytology, ERCP brush cytology, and screening for p53 and ras oncogenes. These advanced techniques should help us to detect pancreatic cancers in high-risk populations at a curative stage and to decrease pancreaticoduodenectomies for benign disease which could otherwise be treated with less morbid procedures. In addition, these tests will help reliably diagnose pancreatic cancer preoperatively. 相似文献
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A postmyocardial infarction left ventricular pseudoaneurysm occurs when a rupture of the ventricular free wall is contained by overlying, adherent pericardium. A postinfarction aneurysm, in contrast, is caused by scar formation resulting in thinning of the myocardium. Although the usual treatment for patients with pseudoaneurysm is urgent surgical repair, the imaging characteristics of pseudoaneurysm and aneurysm, for which treatment is more conservative, are quite similar. The literature on the natural history and imaging characteristics of the two entities is reviewed, and an approach to distinguishing between the two entities is proposed. 相似文献
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Co-injection of the parasite Onchocerca ochengi and the caspase inhibitors z-VAD.fmk and boc-D.fmk into the natural vector Simulium damnosum s.l. led to significantly increased survival of the parasites. Subsequent in situ apoptosis detection assays demonstrated that in the case of boc-D.fmk the enhanced survival was due to a diminished apoptosis level of the microfilariae in vivo. Additional assays using O. ochengi microfilariae which were coinjected with serine protease inhibitors into S. damnosum s.l. revealed that certain serine protease inhibitors can reduce the level of apoptosis. 相似文献
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SE Galbraith A Tiwari MD Baron BT Lund T Barrett SL Cosby 《Canadian Metallurgical Quarterly》1998,72(12):10292-10297
There is evidence that CD46 (membrane cofactor protein) is a cellular receptor for vaccine and laboratory-passaged strains of measles virus (MV). Following infection with these MV strains, CD46 is downregulated from the cell surface, and consequent complement-mediated lysis has been shown to occur upon infection of a human monocytic cell line. The MV hemagglutinin (H) protein alone is capable of inducing this downregulation. Some wild-type strains of MV fail to downregulate CD46, despite infection being prevented by anti-CD46 antibodies. In this study we show that CD46 is also downregulated to the same extent by wild-type, vaccine, and laboratory-passaged strains of rinderpest virus (RPV), although CD46 did not appear to be the receptor for RPV. Expression of the RPV H protein by a nonreplicating adenovirus vector was also found to cause this downregulation. A vaccine strain of peste des petits ruminants virus caused slight downregulation of CD46 in infected Vero cells, while wild-type and vaccine strains of canine distemper virus and a wild-type strain of dolphin morbillivirus failed to downregulate CD46. Downregulation of CD46 can, therefore, be a function independent of the use of this protein as a virus receptor. 相似文献
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The predominant early childhood education philosophy in the United States views formal academic instruction as inappropriate and harmful to the social development of young children. Chinese American immigrants to the United States, however, have been found to teach their young children in more formal ways, to be more directive, and to structure their children's use of time to a greater degree (C. S. Huntsinger, P. E. Jose, F.-R. Liaw, & W.-D. Ching, 1997). Forty European American (20 boys, 20 girls) and 36 2nd-generation Chinese American (18 boys, 18 girls) 1st- and 2nd-grade children and their mothers, fathers, and teachers participated in the Time 2 data collection of this longitudinal study to assess whether the formal academic environment provided by Chinese American parents is linked to poorer social adjustment in their children. Regressions showed that parents' work-oriented methods influenced academic performance but not social adjustment of their children. 相似文献