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Oxygen Tracer Diffusion in Vitreous Silica 总被引:2,自引:0,他引:2
Joseph D. Kalen Rethia S. Boyce James D. Cawley 《Journal of the American Ceramic Society》1991,74(1):203-209
Oxygen diffusion in vitreous silica glass is studied using the gas exchange technique. The tracer concentration profiles are consistent with a model based on two mechanisms, one network and the other interstitial. These processes are coupled through limited network–interstitial exchange. Nuclear reaction analysis and secondary ion mass spectrometry techniques are performed and compared. These results are compared to experiments on transport in thin silica films grown on single-crystal silicon. 相似文献
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Zain Mehdi Michael S. Petronek Jeffrey M. Stolwijk Kranti A. Mapuskar Amanda L. Kalen Garry R. Buettner Joseph J. Cullen Douglas R. Spitz John M. Buatti Bryan G. Allen 《International journal of molecular sciences》2021,22(19)
Interest in the use of pharmacological ascorbate as a treatment for cancer has increased considerably since it was introduced by Cameron and Pauling in the 1970s. Recently, pharmacological ascorbate has been used in preclinical and early-phase clinical trials as a selective radiation sensitizer in cancer. The results of these studies are promising. This review summarizes data on pharmacological ascorbate (1) as a safe and efficacious adjuvant to cancer therapy; (2) as a selective radiosensitizer of cancer via a mechanism involving hydrogen peroxide; and (3) as a radioprotector in normal tissues. Additionally, we present new data demonstrating the ability of pharmacological ascorbate to enhance radiation-induced DNA damage in glioblastoma cells, facilitating cancer cell death. We propose that pharmacological ascorbate may be a general radiosensitizer in cancer therapy and simultaneously a radioprotector of normal tissue. 相似文献
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A forward Raman gain of 2.9 dB has been measured in a 1.1 km low-loss fibre using an LED at 1.118 ?m as a signal source and a CW Nd: YAG laser as a pump. Backward Brillouin scattering, which depletes the pump power towards the end of the fibre, is found to enhance the Raman gain at the front end. 相似文献
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An effective system for perfusing rat liver using complete tissue culture medium and washed calf erythrocytes as oxygen carriers
was devised. Infusion of taurocholate and glucose proved necessary to maintain stable metabolic activity an bile secretion
during a 6-hr period. Perfusate pO2, pCO2 and pH values were monitored continuously and found to be stable. Electron microscopic examination revealed the maintenance
of normal hepatic structure, even after 6 hr. Normal rates of protein and urea synthesis, no leakage of cytoplasmic enzymes,
and continuous bile acid production demonstrated the functional integrity of this system. Using [3H]mevalonic acid as precursor, dolichol, dolichyl phosphate, ubiquinone and cholesterol were found to be continuously synthesized
in this perfusate, indicating discharge through the ER-Golgi system. The lipoproteins of the perfusate were isolated by ultracentrifugation
and characterized with respect to size distribution and lipid composition. Dolichol was found in VLDL, LDL and HDL fractions,
with the highest concentration present in the latter. In rat and human blood plasma this lipid was mainly associated with
HDL. The ubiquinone in the perfusate was primarily associated with the VLDL fraction, while in rat plasma it was found more
evenly distributed among all the three lipoprotein fractions studied. Dolichol, ubiquinone and cholesterol were also discharged
to the bile, whereas dolichyl phosphate was not. Thus, newly-synthesized dolichol and ubiquinone are transported out of the
hepatocyte to the blood and to the bile. 相似文献
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