The main sources of nssSO 2- 4 and NO - 3 were summarized in this paper. By analyzing the spatial distribution features of major ions in Antarctic ice sheet and studying on the different time of the same volca...The main sources of nssSO 2- 4 and NO - 3 were summarized in this paper. By analyzing the spatial distribution features of major ions in Antarctic ice sheet and studying on the different time of the same volcanic event recorded by different ice cores from different regions in Antarctica, this paper intends to study the transmission path of nssSO 2- 4 and NO - 3. Results show that nssSO 2- 4 and NO - 3 are transmitted to the ice sheet through long distance and high altitude. The procedure of the transmission is that nssSO 2- 4 and NO - 3 are transmitted to the level between the top of troposphere and the bottom of stratosphere, then subsided to the ice sheet surface and spread to other regions.展开更多
The nitrogen transformation in maize soil after application of different organic manure was studied. The nitrogen mineralization in surface soil, NO - 3-N dynamics and distribution in soil profile, and N 2O emissio...The nitrogen transformation in maize soil after application of different organic manure was studied. The nitrogen mineralization in surface soil, NO - 3-N dynamics and distribution in soil profile, and N 2O emission were investigated. Eight treatments were laid out randomizing with three replications in 24 plots: maize plantation without fertilizer(CK1), bare soil without maize plantation and fertilization(CK2), swine manure(S1, S2), poultry manure(P1, P2), and cattle manure(C1, C2). Three manures were applied at two application levels(15 t/hm 2 and 30 t/hm 2). The results indicated that NH + 4-N in surface soil showed the same temporal pattern without much variation among different treatments. But NO - 3-N in the same layer exhibited large temporal pattern in all treatments, which was mainly due to its easy eluviations of NO - 3-N in soil, its transformation to N 2O and the influence of precipitation. The distribution of NO - 3-N in the soil profile during maize growing season showed the leaching tendency from surface soil to subsoil, which was different among the treatments. The poultry treatments showed the largest leaching tendency. The study also revealed that the emissions of N 2O were affected by the application of organic manures in the order of P2>S2>C2>P1>S1>C1>CK1>CK2. All these results showed that organic manure applications significantly affect nitrogen transformation and distribution in maize soil. Considering N 2O emission and NO - 3-N leaching, the management of organic manure in the agriculture needs further studies.展开更多
To study the protective effect of rosuvastatin on ischemic brain injury and its mechanism, focal cerebral ischemia/reperfusion was induced by occlusion of the middle cerebral artery （MCA） using the intra-luminal fil...To study the protective effect of rosuvastatin on ischemic brain injury and its mechanism, focal cerebral ischemia/reperfusion was induced by occlusion of the middle cerebral artery （MCA） using the intra-luminal filament technique. The cerebral blood flow was monitored with laser-Doppler flowmetry （LDF）. The slices of brain tissue were stained with cresyl-violet. The cerebral volume of infarction and edema were quantified with ImageJ software. The expressions of endothelial NO synthase （eNOS） and activated caspase-3 were detected with Western blot. The inducible NO synthase （iNOS） positive cells were immunohistochemically observed. The results demonstrated that rosuvastatin （20 mg/kg） could remarkably decrease infarct volume and cerebral edema after MCAO 90 min/reperfusion 24 h. Western blots showed that the expression of eNOS in cerebral cortex before and after ischemia was （100±43.3） %, （1668.9± 112.2） % respectively （P〈0.001）, rosuvastatin significantly up-regulated the expression of eNOS in non-ischemic cortex （P〈0.001）, whereas in ischemic cortex of rosuvastatin group the expression of eNOS was （1678.8 ± 121.3） %. There was no expression of activated caspase-3 in non-ischemic cortex, nonetheless the expression of activated caspase-3 increased after ischemia, and rosuvastatin significantly diminished it （P〈0.01）. Immunohistochemistry revealed no iNOS-positive cells in non-ischemic brain area, while in ischemic brain area the number of iNOS positive cells went up, and rosuvastatin could significantly reduced them. Consequently, the mechanisms of rosuvastatin＇s neural protection on ischemic brain injury are to enhance expression of eNOS, to inhibit expression of iNOS and activated caspase-3.展开更多
文摘The main sources of nssSO 2- 4 and NO - 3 were summarized in this paper. By analyzing the spatial distribution features of major ions in Antarctic ice sheet and studying on the different time of the same volcanic event recorded by different ice cores from different regions in Antarctica, this paper intends to study the transmission path of nssSO 2- 4 and NO - 3. Results show that nssSO 2- 4 and NO - 3 are transmitted to the ice sheet through long distance and high altitude. The procedure of the transmission is that nssSO 2- 4 and NO - 3 are transmitted to the level between the top of troposphere and the bottom of stratosphere, then subsided to the ice sheet surface and spread to other regions.
文摘The nitrogen transformation in maize soil after application of different organic manure was studied. The nitrogen mineralization in surface soil, NO - 3-N dynamics and distribution in soil profile, and N 2O emission were investigated. Eight treatments were laid out randomizing with three replications in 24 plots: maize plantation without fertilizer(CK1), bare soil without maize plantation and fertilization(CK2), swine manure(S1, S2), poultry manure(P1, P2), and cattle manure(C1, C2). Three manures were applied at two application levels(15 t/hm 2 and 30 t/hm 2). The results indicated that NH + 4-N in surface soil showed the same temporal pattern without much variation among different treatments. But NO - 3-N in the same layer exhibited large temporal pattern in all treatments, which was mainly due to its easy eluviations of NO - 3-N in soil, its transformation to N 2O and the influence of precipitation. The distribution of NO - 3-N in the soil profile during maize growing season showed the leaching tendency from surface soil to subsoil, which was different among the treatments. The poultry treatments showed the largest leaching tendency. The study also revealed that the emissions of N 2O were affected by the application of organic manures in the order of P2>S2>C2>P1>S1>C1>CK1>CK2. All these results showed that organic manure applications significantly affect nitrogen transformation and distribution in maize soil. Considering N 2O emission and NO - 3-N leaching, the management of organic manure in the agriculture needs further studies.
基金This project was supported by a grant from National Natural Sciences Foundation of China (No. 30472234), and the National Center of Competence in Research Neural Plastic-ity and Repair of Switzerland (3200B0-100790/1).
文摘To study the protective effect of rosuvastatin on ischemic brain injury and its mechanism, focal cerebral ischemia/reperfusion was induced by occlusion of the middle cerebral artery （MCA） using the intra-luminal filament technique. The cerebral blood flow was monitored with laser-Doppler flowmetry （LDF）. The slices of brain tissue were stained with cresyl-violet. The cerebral volume of infarction and edema were quantified with ImageJ software. The expressions of endothelial NO synthase （eNOS） and activated caspase-3 were detected with Western blot. The inducible NO synthase （iNOS） positive cells were immunohistochemically observed. The results demonstrated that rosuvastatin （20 mg/kg） could remarkably decrease infarct volume and cerebral edema after MCAO 90 min/reperfusion 24 h. Western blots showed that the expression of eNOS in cerebral cortex before and after ischemia was （100±43.3） %, （1668.9± 112.2） % respectively （P〈0.001）, rosuvastatin significantly up-regulated the expression of eNOS in non-ischemic cortex （P〈0.001）, whereas in ischemic cortex of rosuvastatin group the expression of eNOS was （1678.8 ± 121.3） %. There was no expression of activated caspase-3 in non-ischemic cortex, nonetheless the expression of activated caspase-3 increased after ischemia, and rosuvastatin significantly diminished it （P〈0.01）. Immunohistochemistry revealed no iNOS-positive cells in non-ischemic brain area, while in ischemic brain area the number of iNOS positive cells went up, and rosuvastatin could significantly reduced them. Consequently, the mechanisms of rosuvastatin＇s neural protection on ischemic brain injury are to enhance expression of eNOS, to inhibit expression of iNOS and activated caspase-3.
