[Semen quality of infertile men carrying hepatitis B virus].

Objective: To study the semen parameters of infertile men carrying hepatitis B virus (HBV) and the influence of HBV infection on semen quality.

Methods: We collected the semen samples from 782 infertility males aged 25－35 years old. According to the results of serological examinations, we divided the patients into groups A (HBsAg, HBeAb and HBcAb positive, n = 286), B (HBsAg, HBeAg and HBcAb positive, n = 230) and C (non-HBV control, n = 266), and comparatively analyzed the routine semen parameters, sperm acrosin activity, sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) among the three groups of patients.

Increasing rates of long-term nitrogen deposition consistently increased litter decomposition in a semi-arid grassland.

The continuing nitrogen (N) deposition observed worldwide alters ecosystem nutrient cycling and ecosystem functioning. Litter decomposition is a key process contributing to these changes, but the numerous mechanisms for altered decomposition remain poorly identified. We assessed these different mechanisms with a decomposition experiment using litter from four abundant species (Achnatherum sibiricum, Agropyron cristatum, Leymus chinensis and Stipa grandis) and litter mixtures representing treatment-specific community composition in a semi-arid grassland under long-term simulation of six different rates of N deposition.