RESUMO
At present, traditional methods on statistics have limitations in controlling time- varying confounding. This paper introduces an analysis method, parametric g-formula, which would adjust time-varying confounding, and also exemplifies the steps of its implementation for purpose to provide a new reference for researchers to deal with long-term observational data.
RESUMO
In the studies of modem epidemiology,exposure in a short term cannot fully elaborate the mechanism of the development of diseases or health-related events.Thus,lights have been shed on to life course epidemiology,which studies the exposures in early life time and their effects related to the development of chronic diseases.When exploring the mechanism leading from one exposure to an outcome and its effects through other factors,due to the existence of time-variant effects,conventional statistic methods could not meet the needs of etiological analysis in life course epidemiology.This paper summarizes the dynamic path analysis model,including the model structure and significance,and its application in life course epidemiology.Meanwhile,the procedure of data processing and etiology analyzing were introduced.In conclusion,dynamic path analysis is a useful tool which can be used to better elucidate the mechanisms that underlie the etiology of chronic diseases.
RESUMO
In the studies of modem epidemiology,exposure in a short term cannot fully elaborate the mechanism of the development of diseases or health-related events.Thus,lights have been shed on to life course epidemiology,which studies the exposures in early life time and their effects related to the development of chronic diseases.When exploring the mechanism leading from one exposure to an outcome and its effects through other factors,due to the existence of time-variant effects,conventional statistic methods could not meet the needs of etiological analysis in life course epidemiology.This paper summarizes the dynamic path analysis model,including the model structure and significance,and its application in life course epidemiology.Meanwhile,the procedure of data processing and etiology analyzing were introduced.In conclusion,dynamic path analysis is a useful tool which can be used to better elucidate the mechanisms that underlie the etiology of chronic diseases.
RESUMO
In modern biology and biotechnology research, recombinant gene expression has been the most popular method to obtain the target protein. In recent years, many foreign genes have been efficiently expressed in Escherichia coli. However, proteins encoded by animal, plant or mesophilic microbial genes often lose activities or become denatured within a few hours at regular growth temperatures for E. coli; some other target proteins are toxic to host cells and therefore difficult to be over-expressed. The new T-vector, pEXC-T, was constructed by combining TA cloning and cold-shock induction to obtain high expression levels with low costs. This paper reports the construction of pEXC-T and optimization of induction techniques for gene expression. Two instable proteins were tested and successfully expressed in soluble form by using pEXC vector. The development of pEXC-T offers a convenient technique for the preparations of recombinant proteins to be used in structure/function studies, or as diagnostic markers and medicinal proteins.