199 research outputs found

    The Synthesis of (E)-4-Thio-5-(2-Bromovinyl)Uridine/Deoxyuridine and Its Characterization and Cytotoxicity

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    (E)-4-Thio-5-(2-brominevinyl)uridine/2'-deoxyuridine(8a/8b) were efficiently and in an environmental friendly way synthesized from uridine/2'-deoxyuridine (1a/1b) that were first transformed to (E)-(2-brominevinyl) uridine / 2'-deoxyuridine(5a/5b) via iodination, selective oxidation, Heck reaction steps. The resulting products (5a/5b) were then converted to the targets (8a/8b) through esterification, thio-reaction of carbonyl, hydrolysis steps. Two new compounds (8a/8b) and three new intermediates (7a 7b 10) were obtained, and their structures have been fully characterized by 1H NMR, 13C NMR, IR, UV, HR-MS, X-Ray. The study of 8a and their derivatives regarding cytotoxicity was carried out by using MTT experiment method, and the initial findings suggest (E)-4-Thio-5-(2-brominevinyl) uridine/ 2'-deoxyuridine (8a / 8b) would be potential antitumor drugs

    Environmental Strategy, Institutional Force, and Innovation Capability: A Managerial Cognition Perspective

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    Abstract(#br)Despite the rising interest in environmental strategies, few studies have examined how managerial cognition of such strategies influences actual innovation capability development. Taking a managerial cognition perspective, this study investigates how managers’ perceptions of institutional pressures relate to their focus on proactive environmental strategy, which in turn affects firms’ realized innovation capability. The findings from a primary survey and three secondary datasets of publicly listed companies in China reveal that managers’ perceived business and social pressures are positively associated with their focus on proactive environmental strategy, which consequently fosters innovation capability development. Moreover, state ownership and government administrative..

    Strong semismoothness of eigenvalues of symmetric matrices and its application to inverse eigenvalue problems

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    10.1137/S0036142901393814SIAM Journal on Numerical Analysis4062352-2367SJNA

    Effects of Remote Ischemic Preconditioning on Decreasing Troponin Release in Patients Not Taking Sulfonylureas After Cardiac Surgery – A Meta-Analysis

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    ABSTRACT Introduction: Remote ischemic preconditioning (RIPC) is a new noninvasive myocardial protection strategy that uses blood pressure cuf inflation to simulate transient non-fatal ischemia to protect the myocardium and reduce ischemia-reperfusion injury. Sulfonylureas may mask the effects of RIPC due to their cardioprotec-tive effect. This meta-analysis aimed to evaluate whether RIPC, in the absence of sulfonylureas, reduces troponin release in patients undergoing cardiac surgery. Methods: We conducted a meta-analysis of randomized controlled clinical trials to determine whether RIPC can reduce postoperative troponin release in cardiac surgery patients undergoing cardiopulmonary bypass without treatment with sulfonylureas. The data were normalized to equivalent units prior to the analysis. A random-effects model was used to provide more conservative estimate of the effects in the presence of known or unknown heterogeneity. Results: Six studies with a total of 570 participants were included. The analysis showed that troponin release was lower in the RIPC group than in the control group at six hours (test of standardized mean differences = 0, Z=3.64, P 60 minutes, RIPC reduced troponin release at six hours (Z=2.84, P=0.005), 24 hours (Z=2.64, P=0.008), and 48 hours (Z=2.87, P=0.004) postoperatively. Conclusion: In cardiac surgery patients who are not taking sulfonylureas, RIPC can reduce troponin release at six and 48 hours postoperatively; hence, RIPC may serve significant benefits in certain cardiac surgery patients

    Synchronous post-acceleration of laser-driven protons in helical coil targets by controlling the current dispersion

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    Post-acceleration of protons in helical coil targets driven by intense, ultrashort laser pulses can enhance ion energy by utilizing the transient current from the targets’ self-discharge. The acceleration length of protons can exceed a few millimeters, and the acceleration gradient is of the order of GeV/m. How to ensure the synchronization between the accelerating electric field and the protons is a crucial problem for efficient post-acceleration. In this paper, we study how the electric field mismatch induced by current dispersion affects the synchronous acceleration of protons. We propose a scheme using a two-stage helical coil to control the current dispersion. With optimized parameters, the energy gain of protons is increased by four times. Proton energy is expected to reach 45 MeV using a hundreds-of-terawatts laser, or more than 100 MeV using a petawatt laser, by controlling the current dispersion
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