Publications by authors named "Jiusheng Ren"

Climate warming affects the carbon cycle of northern peatlands through temperature rises and a changing carbon availability. To clarify the effects of elevated temperature and labile carbon addition on SOC mineralization, as well as their microbial driving mechanisms, topsoil (0-10 cm) and subsoil (10-20 cm) were collected from a peatland in the Great Hing'an Mountains and incubated with or without C-glucose at 10 °C and 15 °C for 42 days. The results showed that 5 °C warming significantly stimulated SOC mineralization along with NH-N and NO-N content increases, as well as a decrease in invertase and urease activities.

View Article and Find Full Text PDF

Diurnal freeze-thaw cycles (FTCs) occur in the spring and autumn in boreal wetlands as soil temperatures rise above freezing during the day and fall below freezing at night. A surge in methane emissions from these systems is frequently documented during spring FTCs, accounting for a large portion of annual emissions. In boreal wetlands, methane is produced as a result of syntrophic microbial processes, mediated by a consortium of fermenting bacteria and methanogenic archaea.

View Article and Find Full Text PDF

Nitrogen (N) availability affects litter decomposition and nutrient dynamics, especially in N-limited ecosystems. We investigated the response of litter decomposition to N additions in Eriophorum vaginatum and Vaccinium uliginosum peatlands. These two species dominate peatlands in Northeast China.

View Article and Find Full Text PDF

Effects of the three-dimensional residual stresses on the mechanical properties of arterial walls are analyzed in this paper, based on the model which considered the bending and stretching both in the circumferential and axial directions of the three distinct arterial layers. Moreover, different constitutive models are proposed to quantify the nonlinear mechanics of the three distinct layers and the important constituents, i.e.

View Article and Find Full Text PDF

Aims: Our study aims to clarify the effects of demecolcine, alone or in combination with sucrose on bovine oocyte protrusion rate, MAPK1 protein level and c-mos gene expression level.

Methods: The effects of the demecolcine concentration, treatment duration, and synergistic effects with sucrose solution on the rate of membrane protrusions of bovine oocytes were investigated. Using real-time fluorescent quantitative PCR, western blot analysis, and immunofluorescence assays, the expression of the maternal c-mos gene, the protein level of mitogen-activated protein kinase 1 (MAPK1), and the change in the localization of spindles and nuclei during the demecolcine treatment were analyzed in bovine oocytes.

View Article and Find Full Text PDF

Growth, residual stresses and mechanical responses of arterial walls under the inner pressure are investigated within the framework of a finite deformation hyper-elasticity theory. A biomechanical model for a two-layer thick-walled circular cylindrical tube is proposed to address the mechanical effects of finite volumetric growth and residual stresses of arterial walls. The active stress due to smooth muscle tone in the media and the dispersion of collagen fiber orientations in the adventitia are also considered.

View Article and Find Full Text PDF

Effects of dispersion of the fiber orientation on the mechanical property of the arterial wall in health and disease subjected to the combined internal pressure and axial loading are examined within the framework of the finite deformation hyper-elasticity theory. Taking into account the residual stress, a two layer thick-walled circular cylindrical tube model with the fiber-reinforced incompressible composite hyper-elastic material is employed. Stress-radius curves and stress distributions of the arterial wall are given in health and disease considering dispersion of the fiber orientation.

View Article and Find Full Text PDF