Biochar mitigates the N2O emissions from acidic soil by increasing the nosZ and nirK gene abundance and soil pH.

Nitrous oxide (N2O) is a pervasive greenhouse gas, and soil management practices greatly affect its release into the atmosphere. Soil pH management (particularly increasing the pH) using biochar can seriously affect soil N2O emissions. The current incubation experiment was conducted to explore the response of N2O emissions from acidic soils using various doses of biochar. Soil with a pH of 5.48 was treated with rice straw biochar at different doses (0%, 1% and 2%) and incubated with 60% water-filled pore spaces (WFPS). The experiment was conducted in a completely randomized design (CRD) with three replications. The soil N2O emissions, pH, NH4+-N, NO3--N, microbial biomass carbon (MBC), and nosZ and nirK gene abundance were determined at various intervals throughout the study. The biochar application (2%) increased the soil pH (from 5.48 to 6.11), triggered the transformation of nitrogen, and augmented the abundance of nosZ and nirK genes. Higher magnitudes of cumulative soil N2O emissions (48.60 µg kg-1) were noted in the control (no biochar) compared to 1% (28.10 µg kg-1) and 2% (14.50 µg kg-1) biochar application. The 2% biochar application more effectively decreased the soil N2O emissions, mainly because of the increased nosZ and nirK gene abundance at higher soil pH levels. The findings suggest that the amelioration of acidic soil with rice straw biochar can considerably control soil N2O emissions by elevating the soil pH and the abundance of nosZ and nirK genes.

Animal models of intracristal and membranous ventricular septal defect / 中国组织工程研究

BACKGROUND:Surrounding structure of intracristal ventricular septal defects(IVSD) and membranous ventricular septal defects(MVSD)is complicated,and it is difficult to perform transcatheter closure treatment.Corresponding animal models should be established to define an optimal interventional therapy.OBJECTIVE:To prepare the animal models of IVSD and MVSD under echoeardiogram location.DESIGN:Animal modeling experiment.SETTING:Department of Cardiology,Zhongshan Hospital Affiliated to Fudan University.MATERIALS:Six healthy adult dogs,irrespective of gender,were purchased from Shanghai Experimental Animal Center.Aorta and great saphenous vein stapler-puncher(St.Jude corporation,USA)was used.The main improvement is to cut the plastic shell even,thin,or shorter in order to reduce the resistance when puncturing the"purse"in the fight ventficle and the interventficular septum.Sonos 5500 multifunction ultrasonoscope(Philips,USA)was used,and the frequency of the probe was between 2.5-3.5 MHz.METHODS:Experiments were performed at the Zhongshan Hospital Affiliated to Fudan University and Central Laboratory of Shanghai Institute of Cardiovascular Disease from April to July 2006(biosaflety level 2).After anaesthesia,6 adult dogs were fixed at decumbent position.The interventricular septum was punetured to make the preparation with the location of echocardiography(ECHO)by using the modified aorta and great saphenous vein proximal stapler-puncher.Animal intervention met the Animal Ethical Committee of Fudan University.MAIN OUTCOME MEASURES:One week after the surgery,transthoracic echocardiography examination was used to check the VSD site,the highest shunt flow rate,the pressure difference between both sides of the VSD,as well as pulmonary artenal pressure.RESULTS:The VSD models were successfully established in three survivals and included in the final result.Two models of IVSD and one model of MVSD were examined by ECHO one week after the surgery.The diameter of VSD ranges from 1.8 to 3.6 mm.The Peak Flow Rate of the VSD ranges between 1.8 and 4.0 m/s.The pressure difierence of both sides of the VSD ranges between 42 and 51 mm Hg.The pulmonary arterial systolic pressure ranges from 23 to 29 mm Hg.CoNCLUSION:Located by the ECHO,it is possible to establish animal models of the IVSD and MVSD with the modified aorta and great saphenous vein proximal stapler-puncher.