为探明凉山干热河谷典型坡耕地土壤入渗性能的动态变化特征及其影响因素,选用微型圆盘入渗仪(mini disk infiltrometer)探究不同地表处理和不同时段(5、8、10月)的土壤入渗特征.研究结果表明:坡耕地连续休闲处理的土壤属性和入渗性能动...为探明凉山干热河谷典型坡耕地土壤入渗性能的动态变化特征及其影响因素,选用微型圆盘入渗仪(mini disk infiltrometer)探究不同地表处理和不同时段(5、8、10月)的土壤入渗特征.研究结果表明:坡耕地连续休闲处理的土壤属性和入渗性能动态变化不大,而5月份雨季初期的翻耕扰动是导致土壤属性突变和导水率急剧增加的主要原因,翻耕后的土壤属性和入渗性能至8月可恢复至连续休闲对照的水平;坡耕地种植玉米可显著降低土壤容重和增加团聚体水稳性,从而提升土壤入渗性能;土壤累积入渗量可以用入渗时间的二次多项式方程进行模拟,在Kostiakov、Philip和Green-Ampt 3种常用入渗过程模型中,GreenAmpt模型用于模拟坡耕地土壤水分入渗过程的效果最优.研究结果可为凉山干热河谷地区的坡耕地水分管理及土壤保持措施布设提供依据.展开更多
AIM： To investigate the damaging effect of high-intensity focused ultrasound （HIFU） on cancer cells and the inhibitory effect on tumor growth. METHODS： Hurine H22 hepatic cancer cells were treated with HIFU at the...AIM： To investigate the damaging effect of high-intensity focused ultrasound （HIFU） on cancer cells and the inhibitory effect on tumor growth. METHODS： Hurine H22 hepatic cancer cells were treated with HIFU at the same intensity for different lengths of time and at different intensities for the same length oftime in vitro, the dead cancer cells were determined by trypan blue staining. Two groups of cancer cells treated with HIFU at the lowest and highest intensity were inoculated into mice. Tumor masses were removed and weighed after 2 wk, tumor growth in each group was confirmed pathologically.RESULTS： The death rate of cancer cells treated with HIFU at 1 000 W/cm^2 for 0.5, 1, 2, 4, 8, and 12 s was 3.11±1.21%, 13.37±2.56%, 38.84±3.68%, 47.22±5.76%,87.55±7.32%, and 94.33±8.11%, respectively. A positive relationship between the death rates of cancer cells and the length of HIFU treatment time was found （r = 0.96,P〈0.01）. The death rate of cancer cells treated with HIFU at the intensity of 100, 200, 400, 600, 800, and 1 000 W/cm^2 for 8 s was 26.31±3.26%, 31.00±3.87%, 41.97±5.86%,72.23±8.12%, 94.90±8.67%, and 99.30±9.18%, respectively. A positive relationship between the death rates of cancer cells and the intensities of HIFU treatment was confirmed （r= 0.98, P〈0.01）. The cancer cells treated with HIFU at 1 000 W/cm^2 for 8 s were inoculated intomice ed into. The tumor inhibitory rate was 90.35% compared to the control （P〈0.01）. In the experimental group inoculated with the cancer cells treated with HIFU at 1 000 W/cm^2 for 0.5 s, the tumor inhibitory rate was 22.9% （P〈0.01）. By pathological examination, tumor growth was confirmed in 8 out of 14 mice （57.14%, 8/14） inoculated with the cancer cells treated with HIFU at 1 000 W/cm^2 for 8 s, which was significantly lower than that in the control （100%, 15/15, P〈O.05）.CONCLUSION： HIFU is effective on killing or damage of H22 hepatic cancer cells in vitro and on inhibiting tumor growth in mice ex vivo.展开更多
文摘为探明凉山干热河谷典型坡耕地土壤入渗性能的动态变化特征及其影响因素,选用微型圆盘入渗仪(mini disk infiltrometer)探究不同地表处理和不同时段(5、8、10月)的土壤入渗特征.研究结果表明:坡耕地连续休闲处理的土壤属性和入渗性能动态变化不大,而5月份雨季初期的翻耕扰动是导致土壤属性突变和导水率急剧增加的主要原因,翻耕后的土壤属性和入渗性能至8月可恢复至连续休闲对照的水平;坡耕地种植玉米可显著降低土壤容重和增加团聚体水稳性,从而提升土壤入渗性能;土壤累积入渗量可以用入渗时间的二次多项式方程进行模拟,在Kostiakov、Philip和Green-Ampt 3种常用入渗过程模型中,GreenAmpt模型用于模拟坡耕地土壤水分入渗过程的效果最优.研究结果可为凉山干热河谷地区的坡耕地水分管理及土壤保持措施布设提供依据.
基金Supported by the Grant from National Economic Trade Committee, No. 2000-312-2
文摘AIM： To investigate the damaging effect of high-intensity focused ultrasound （HIFU） on cancer cells and the inhibitory effect on tumor growth. METHODS： Hurine H22 hepatic cancer cells were treated with HIFU at the same intensity for different lengths of time and at different intensities for the same length oftime in vitro, the dead cancer cells were determined by trypan blue staining. Two groups of cancer cells treated with HIFU at the lowest and highest intensity were inoculated into mice. Tumor masses were removed and weighed after 2 wk, tumor growth in each group was confirmed pathologically.RESULTS： The death rate of cancer cells treated with HIFU at 1 000 W/cm^2 for 0.5, 1, 2, 4, 8, and 12 s was 3.11±1.21%, 13.37±2.56%, 38.84±3.68%, 47.22±5.76%,87.55±7.32%, and 94.33±8.11%, respectively. A positive relationship between the death rates of cancer cells and the length of HIFU treatment time was found （r = 0.96,P〈0.01）. The death rate of cancer cells treated with HIFU at the intensity of 100, 200, 400, 600, 800, and 1 000 W/cm^2 for 8 s was 26.31±3.26%, 31.00±3.87%, 41.97±5.86%,72.23±8.12%, 94.90±8.67%, and 99.30±9.18%, respectively. A positive relationship between the death rates of cancer cells and the intensities of HIFU treatment was confirmed （r= 0.98, P〈0.01）. The cancer cells treated with HIFU at 1 000 W/cm^2 for 8 s were inoculated intomice ed into. The tumor inhibitory rate was 90.35% compared to the control （P〈0.01）. In the experimental group inoculated with the cancer cells treated with HIFU at 1 000 W/cm^2 for 0.5 s, the tumor inhibitory rate was 22.9% （P〈0.01）. By pathological examination, tumor growth was confirmed in 8 out of 14 mice （57.14%, 8/14） inoculated with the cancer cells treated with HIFU at 1 000 W/cm^2 for 8 s, which was significantly lower than that in the control （100%, 15/15, P〈O.05）.CONCLUSION： HIFU is effective on killing or damage of H22 hepatic cancer cells in vitro and on inhibiting tumor growth in mice ex vivo.
