mutations in the human hepatitis b virus (hbv) genome contribute to its escape from host immune surveillance and result in persistent infections. the aim of this study was to characterize the molecular variations of the surface gene and protein in chronically-infected patients from the southern part of iran. the  surface  genes  from  12  hbv  chronic  carriers  were  amplified, sequenced  and ...

BACKGROUND It has recently been shown that levels of diversity in mitochondrial DNA are remarkably constant across animals of diverse census population sizes and ecologies, which has led to the suggestion that the effective population of mitochondrial DNA may be relatively constant. RESULTS Here we present several lines of evidence that suggest, to the contrary, that the effective population ...

background: celiac sprue (gluten sensitive enteropathy) is an autoimmune disease which is hereditary and its pathology mainly bases on immunologic intolerance to gluten. it has a vast variety of signs and symptoms and its clinical features range from a silent disease to a typical gastrointestinal disorder. in this study we reviewed and summarized some other related issues about this disease and...

A technique for tracing stem cells and their descendants reveals how the lining of the airways is maintained, and how this process is altered in smokers.

Anyone who has ever been drenched by a sudden downpour that failed to follow the weather forecast has a feeling for the problem that faces climate modelers. Small-scale features like thunderstorms, in which the core might be 5 km across, are much harder to predict in global models for weather and climate then are quantities like temperature that tend to vary on larger scales. Rain and snowfall,...