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排序方式: 共有1444条查询结果,搜索用时 15 毫秒
1.
Kumar Kuila Saikat Kumbhakar Partha Sekhar Tiwary Chandra Kumar Kundu Tarun 《Journal of Materials Science》2022,57(19):8658-8675
Journal of Materials Science - Hybrid oxidation methodologies (HOMs) and active site enrichment of 2D nanocatalyst through defects induction are ubiquitously used for generating adequate reactive... 相似文献
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Renal cell carcinoma may metastasize to the head and neck region at different stages of its evolution. We present a case of an undiagnosed renal cell carcinoma presenting as an ear polyp, and discuss the difficulties of the diagnosis and the management of these tumours. 相似文献
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Sintering and grain growth of nano-crystalline undoped ZnO has been studied in detail over a wide range of temperature and holding time. Below 800 °C, sintering of over 70% theoretical density is not observed, irrespective of particle size. At 900 °C for 6 h, the nano-crystalline sample sinters to 99% of theoretical density whereas the density for as received sample is 93% of theoretical density. However, at 1300 °C or higher, the densification is found to be much faster and after a few hours becomes independent of holding time. Grain growth studies reveal a similar feature of attaining saturation over holding time. The average saturated grain size is found to be ∼1.5 and ∼2.2 μm at 800 and 900 °C, respectively, while at 1300 °C or higher, it is in between 12 and 13 μm. 相似文献
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P Ferroni L Lenti F Martini F Ciatti GM Pontieri PP Gazzaniga 《Canadian Metallurgical Quarterly》1997,77(3):548-554
Gangliosides may play functional roles in platelet physiology, therefore this study has been designed to evaluate whether changes in ganglioside composition may occur as a consequence of platelet activation. The results obtained indicate that lactosylceramide and GM3 are the major glycosphingolipids of human platelets. The lipid-bound sialic acid (LBSA) content was 1.27 +/- 0.04 micrograms/mg of protein. Resting platelets did not express GD3; GD3 was synthesized upon platelet activation (24 +/- 8 ng/mg of protein). The stimulation of platelets with adenosine diphosphate showed the appearance of GD3 even in the absence of degranulation. Finally, incorporation of pyrene-labeled GM3 into platelet membranes, followed by stimulation with adenosine diphosphate, resulted in the appearance of a fluorescent band comigrating with GD3. The present studies indicate that sialytransferase activation may occur as an early event following platelet stimulation, leading to GD3 synthesis mainly from the GM3 pool. 相似文献
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MS Ali PP Sayeski LB Dirksen DJ Hayzer MB Marrero KE Bernstein 《Canadian Metallurgical Quarterly》1997,272(37):23382-23388
Angiotensin II is the effector molecule of the renin-angiotensin system. Virtually all of its biochemical actions are mediated through a single class of cell-surface receptors called AT1. These receptors contain the structural features of the seven-transmembrane, G-protein-coupled receptor superfamily. Angiotensin II, acting through the AT1 receptor, also stimulates the Jak/STAT pathway by inducing ligand-dependent Jak2 tyrosine phosphorylation and activation. Here, we show that a glutathione S-transferase fusion protein containing the carboxyl-terminal 54 amino acids of the rat AT1A receptor physically binds to Jak2 in an angiotensin II-dependent manner. Deletional analysis, using both in vitro protocols and cell transfection analysis, showed that this association is dependent on the AT1A receptor motif YIPP (amino acids 319-322). The wild-type AT1A receptor can induce Jak2 tyrosine phosphorylation. In contrast, an AT1A receptor lacking the YIPP motif is unable to induce ligand-dependent phosphorylation of Jak2. Competition experiments with synthetic peptides suggest that each of the YIPP amino acids, including tyrosine 319, is important in Jak2 binding to the AT1A receptor. The binding of the AT1A receptor to the intracellular tyrosine kinase Jak2 supports the concept that the seven-transmembrane superfamily of receptors can physically associate with enzymatically active intracellular proteins, creating a signaling complex mechanistically similar to that observed with growth factor and cytokine receptors. 相似文献
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PP Lee CA Jackson DA Relles 《Canadian Metallurgical Quarterly》1995,102(12):1964-71; discussion 1971-2
PURPOSE: To estimate the workforce supply and requirements for eye care in the United States. METHODS: Three models were constructed for analysis: supply of providers, public health need for eye care, and demand (utilization) for eye care. Ophthalmologists, other physicians, and optometrists were included in the models. Public health need was determined by applying condition-specific prevalence and incidence rates from population-based and other epidemiologic studies. Demand was determined by use of national databases, such as the National Ambulatory Care Survey, National Hospital Discharge Survey, and Medicare Part B. Time requirements for care were obtained through a stratified sample survey of the membership of the American Academy of Ophthalmology. RESULTS: Under modeling assumptions that use a work-time ratio of one between optometrists and ophthalmologists and between specialist and generalist ophthalmologists, a significant excess of eye care providers exists relative to both public health need and demand. Changes in the work-time ratio, work-hours per year per provider, care patterns for the same condition, or other factors could significantly reduce or eliminate the surplus relative to need. CONCLUSION: If optometrists are the preferred primary eye care provider, ophthalmologists would be in excess under all demand scenarios and all need scenarios where the optometrist to ophthalmologist work-time ratio is greater than 0.6. No excess of ophthalmologists would exist if ophthalmologists are the preferred primary eye care provider. Data on the appropriate work time ratio will help refine estimates of the imbalance between supply and requirements. 相似文献
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All animal DNA viruses except pox virus utilize the cell nucleus as the site for virus reproduction. Yet, a critical viral infection process, nuclear targeting of the viral genome, is poorly understood. The role of capsid proteins in nuclear targeting of simian virus 40 (SV40) DNA, which is assessed by the nuclear accumulation of large tumor (T) antigen, the initial sign of the infectious process, was tested by two independent approaches: antibody interception experiments and reconstitution experiments. When antibody against viral capsid protein Vp1 or Vp3 was introduced into the cytoplasm, the nuclear accumulation of T antigen was not observed in cells either infected or cytoplasmically injected with virion. Nuclearly introduced anti-Vp3 IgG also showed the inhibitory effect. In the reconstitution experiments, SV40 DNA was allowed to interact with protein components of the virus, either empty particles or histones, and the resulting complexes were tested for the capability of protein components to target the DNA to the nucleus from cytoplasm as effectively as the targeting of DNA in the mature virion. In cells injected with empty particle-DNA, but not in minichromosome-injected cells, T antigen was observed as effectively as in SV40-injected cells. These results demonstrate that SV40 capsid proteins can facilitate transport of SV40 DNA into the nucleus and indicate that Vp3, one of the capsid proteins, accompanies SV40 DNA as it enters the nucleus during virus infection. 相似文献