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Olkhovskiy I. A. Stolyar M. A. Lagutinskaya D. V. Zakhvataev V. E. Khlebopros R. G. 《Biophysics》2019,64(1):62-66
Biophysics - Abstract—The influence of exposure to mobile phone radiation on in vitro platelet aggregation has been studied. It has been shown that a 30-min exposure of blood samples to... 相似文献
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Biophysics - A glutamate model of stroke was analyzed from the standpoint of the development of a typical pathological process that is thought to occur when major regulatory mechanisms are... 相似文献
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Soohyun Ahn Johan Lim Myunghee Cho Paik Ralph L. Sacco Mitchell S. Elkind 《Biometrical journal. Biometrische Zeitschrift》2018,60(4):797-814
In cohort studies the outcome is often time to a particular event, and subjects are followed at regular intervals. Periodic visits may also monitor a secondary irreversible event influencing the event of primary interest, and a significant proportion of subjects develop the secondary event over the period of follow‐up. The status of the secondary event serves as a time‐varying covariate, but is recorded only at the times of the scheduled visits, generating incomplete time‐varying covariates. While information on a typical time‐varying covariate is missing for entire follow‐up period except the visiting times, the status of the secondary event are unavailable only between visits where the status has changed, thus interval‐censored. One may view interval‐censored covariate of the secondary event status as missing time‐varying covariates, yet missingness is partial since partial information is provided throughout the follow‐up period. Current practice of using the latest observed status produces biased estimators, and the existing missing covariate techniques cannot accommodate the special feature of missingness due to interval censoring. To handle interval‐censored covariates in the Cox proportional hazards model, we propose an available‐data estimator, a doubly robust‐type estimator as well as the maximum likelihood estimator via EM algorithm and present their asymptotic properties. We also present practical approaches that are valid. We demonstrate the proposed methods using our motivating example from the Northern Manhattan Study. 相似文献
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Two MC1R loss‐of‐function alleles in cream‐coloured Australian Cattle Dogs and white Huskies 下载免费PDF全文