Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N ferti...Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.展开更多
Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^...Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^＋-N concentration in the field floodwater affecting ammonia loss were also investigated. Results show that the ammonia loss by volatilization accounted for 18.6%-38.7% of urea applied at different stages, the greatest loss took place when urea was applied at the tillering stage, the smallest at the ear bearing stage, and the intermediate loss at the basal stage. The greatest loss took place within 7 d following the fertilizer application. Ammonia volatilization losses at three fertilization stages were significantly correlated with the ammonium concentration in the field floodwater after the fertilizer was applied. ^15N balance experiment indicated that the use efficiency of urea by rice plants ranged between 24.4% and 28.1%. At the early stage of rice growth, the fertilizer nitrogen use efficiency was rather low, only about 12%. The total amount of nitrogen lost from different fertilization stages in the rice field was 44.1%-54.4%, and the ammonia volatilization loss was 25.4%-33.3%. Reducing ammonia loss is an important treatment for improving N use efficiency.展开更多
目的:分析达拉非尼联合曲美替尼治疗黑色素瘤致皮肤系统不良反应(ADR)的发生情况及临床特点,为临床安全用药提供参考。方法:检索Web of Science、PubMed、知网和万方数据库,收集国内外相关个案报道并进行分析总结。结果:共筛选出有效文...目的:分析达拉非尼联合曲美替尼治疗黑色素瘤致皮肤系统不良反应(ADR)的发生情况及临床特点,为临床安全用药提供参考。方法:检索Web of Science、PubMed、知网和万方数据库,收集国内外相关个案报道并进行分析总结。结果:共筛选出有效文献31篇,共38例次,患者年龄主要为31~80岁(89.47%);ADR多发生在用药后90 d内(60.52%);主要临床表现为痤疮样皮疹(18.42%)、肉芽肿性皮炎(13.16%)、脂膜炎(10.53%)、纹身并发症(10.53%)及结节性红斑病变(10.53%);34例患者皮肤ADR痊愈或好转,其中2例永久停用了达拉非尼与曲美替尼,10例继续联合治疗,12例暂停联合治疗,其中11例患者好转或痊愈后重启联合治疗。在重启或继续使用联合治疗的患者中,10例再次出现ADR。结论:本研究中,达拉非尼联合曲美替尼致皮肤系统ADR表现出不同的发生率和特征,且免疫治疗后进行靶向治疗可能增加严重皮肤ADR发生风险。临床在联合使用时应加强用药监测,及时发现ADR并采取适当的防治措施,同时严密监测重启或继续用药所致ADR,确保用药安全。展开更多
基金Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-413-3)National Natural Science Foundation of China (No.30390080)National Basic Research Program of China (No.2005CB121108)
文摘Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.
文摘Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^＋-N concentration in the field floodwater affecting ammonia loss were also investigated. Results show that the ammonia loss by volatilization accounted for 18.6%-38.7% of urea applied at different stages, the greatest loss took place when urea was applied at the tillering stage, the smallest at the ear bearing stage, and the intermediate loss at the basal stage. The greatest loss took place within 7 d following the fertilizer application. Ammonia volatilization losses at three fertilization stages were significantly correlated with the ammonium concentration in the field floodwater after the fertilizer was applied. ^15N balance experiment indicated that the use efficiency of urea by rice plants ranged between 24.4% and 28.1%. At the early stage of rice growth, the fertilizer nitrogen use efficiency was rather low, only about 12%. The total amount of nitrogen lost from different fertilization stages in the rice field was 44.1%-54.4%, and the ammonia volatilization loss was 25.4%-33.3%. Reducing ammonia loss is an important treatment for improving N use efficiency.
文摘目的:分析达拉非尼联合曲美替尼治疗黑色素瘤致皮肤系统不良反应(ADR)的发生情况及临床特点,为临床安全用药提供参考。方法:检索Web of Science、PubMed、知网和万方数据库,收集国内外相关个案报道并进行分析总结。结果:共筛选出有效文献31篇,共38例次,患者年龄主要为31~80岁(89.47%);ADR多发生在用药后90 d内(60.52%);主要临床表现为痤疮样皮疹(18.42%)、肉芽肿性皮炎(13.16%)、脂膜炎(10.53%)、纹身并发症(10.53%)及结节性红斑病变(10.53%);34例患者皮肤ADR痊愈或好转,其中2例永久停用了达拉非尼与曲美替尼,10例继续联合治疗,12例暂停联合治疗,其中11例患者好转或痊愈后重启联合治疗。在重启或继续使用联合治疗的患者中,10例再次出现ADR。结论:本研究中,达拉非尼联合曲美替尼致皮肤系统ADR表现出不同的发生率和特征,且免疫治疗后进行靶向治疗可能增加严重皮肤ADR发生风险。临床在联合使用时应加强用药监测,及时发现ADR并采取适当的防治措施,同时严密监测重启或继续用药所致ADR,确保用药安全。
