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Man‐Lai Tang Ping‐Shing Chan Wai Chan 《Biometrical journal. Biometrische Zeitschrift》2000,42(7):795-806
The one‐degree‐of‐freedom Cochran‐Armitage (C‐A) test statistic for linear trend has been widely applied in various dose‐response studies (e.g., anti‐ulcer medications and short‐term antibiotics, animal carcinogenicity bioassays and occupational toxicant studies). This approximate statistic relies, however, on asymptotic theory that is reliable only when the sample sizes are reasonably large and well balanced across dose levels. For small, sparse, or skewed data, the asymptotic theory is suspect and exact conditional method (based on the C‐A statistic) seems to provide a dependable alternative. Unfortunately, the exact conditional method is only practical for the linear logistic model from which the sufficient statistics for the regression coefficients can be obtained explicitly. In this article, a simple and efficient recursive polynomial multiplication algorithm for exact unconditional test (based on the C‐A statistic) for detecting a linear trend in proportions is derived. The method is applicable for all choices of the model with monotone trend including logistic, probit, arcsine, extreme value and one hit. We also show that this algorithm can be easily extended to exact unconditional power calculation for studies with up to a moderately large sample size. A real example is given to illustrate the applicability of the proposed method. 相似文献
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Jingqiang Zheng Chaohong Guan Huangxu Li Danjun Wang Yanqing Lai Simin Li Jie Li Zhian Zhang 《Liver Transplantation》2024,14(15):2303584
The primary bottleneck hindering the application of hard carbon in sodium-ion batteries (SIBs) anodes lies in its inadequate initial Coulombic efficiency (ICE). Unclear causes of capacity loss at the microscopic level restrict the improvement of hard carbon anodes. Here, two pivotal stages that influence the structure and composition of hard carbon, namely synthesis, and storage are evaluated; subsequently identifying crucial determinants contributing to irreversible capacity loss. The results suggest that undergrown carbon layers allowing the intrusion of solvent molecules into the interior of the hard carbon is a key factor during the synthesis stage, while the gradual formation of oxygen-containing functional groups on the surface of the hard carbon is another factor leading to irreversible loss of capacity during storage stage. This research microscopically clarifies the irreversible capacity loss mechanism on hard carbon and provides guidelines for designing and applying high ICE hard carbon for SIBs. 相似文献
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Organization of intermediate filament, a major component of cytoskeleton, is regulated by protein phosphorylation/dephosphorylation, which is a dynamic process governed by a balance between the activities of involved protein kinases and phosphatases. Blocking dephosphorylation by protein phosphatase inhibitors such as okadaic acid (OA) leads to an apparent activation of protein kinase(s) and to genuine activation of phosphatase-regulated protein kinase(s). Treatment of 9L rat brain tumor cells with OA results in a drastically increased phosphorylation of vimentin, an intermediate filament protein. In-gel renaturing assays and in vitro kinase assays using vimentin as the exogenous substrate indicate that certain protein kinase(s) is activated in OA-treated cells. With specific protein kinase inhibitors, we show the possible involvement of the cdc2 kinase- and p38 mitogen-activated protein kinase (p38MAPK)-mediated pathways in this process. Subsequent in vitro assays demonstrate that vimentin may serve as an excellent substrate for MAPK-activated protein kinase-2 (MAPKAPK-2), the downstream effector of p38MAPK, and that MAPKAPK-2 is activated with OA treatment. Comparative analysis of tryptic phosphopeptide maps also indicates that corresponding phosphopeptides emerged in vimentin from OA-treated cells and were phosphorylated by MAPKAPK-2. Taken together, the results clearly demonstrate that MAPKAPK-2 may function as a vimentin kinase in vitro and in vivo. These findings shed new light on the possible involvement of the p38MAPK signaling cascade, via MAPKAPK-2, in the maintenance of integrity and possible physiological regulation of intermediate filaments. J. Cell. Biochem. 71:169–181, 1998. © 1998 Wiley-Liss, Inc. 相似文献
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Benjamin Chung Howe Lai Hung-Jen Shih Syuan-Hao Syu Ke-Hsun Lin 《The Yale journal of biology and medicine》2021,94(4):609
Introduction: Schwannoma of the male genital system is very uncommon and is mostly treated by surgery. However, prostatic schwannoma presenting with elevated prostate-specific antigen (PSA) level and treated conservatively are extremely rare. Case presentation: Herein, we present a rare case of a prostatic schwannoma in a 65-year-old man who initially presented with an elevated PSA level. Digital rectal examination revealed an enlarged prostate with a palpable hard nodule on the left side. Transrectal ultrasonography revealed an enlarged prostate with a well-defined homogeneously hypoechoic nodule in the left peripheral lobe. Biopsy was done, and histopathology revealed a prostatic schwannoma. Conservative treatment with regular image follow-up was done per the patient’s preference. Mild PSA progression but no worsening of symptoms was found in 6 years of follow-up. Conclusions: PSA elevation could be a rare presentation of prostatic schwannoma. Treatment options other than surgery, such as conservative treatment with close observation, could be feasible for these rare tumors and long-term survivorship can be achieved. 相似文献
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