In this work the effects of O_2 concentration on the pulsed dielectric barrier discharge in helium-oxygen mixture at atmospheric pressure have been numerically researched by using a one-dimensional fluid model in conj...In this work the effects of O_2 concentration on the pulsed dielectric barrier discharge in helium-oxygen mixture at atmospheric pressure have been numerically researched by using a one-dimensional fluid model in conjunction with the chosen key species and chemical reactions.The reliability of the used model has been examined by comparing the calculated discharge current with the reported experiments. The present work presents the following significant results. The dominative positive and negative particles are He_2~＋ and O_2^-, respectively, the densities of the reactive oxygen species（ROS） get their maxima nearly at the central position of the gap, and the density of the ground state O is highest in the ROS. The increase of O_2 concentration results in increasingly weak discharge and the time lag of the ignition. For O_2 concentrations below 1.1%,the density of O is much higher than other species, the averaged dissipated power density presents an evident increase for small O_2 concentration and then the increase becomes weak. In particular,the total density of the reactive oxygen species reaches its maximums at the O_2 concentration of about 0.5%. This characteristic further convinces the experimental observation that the O_2 concentration of 0.5% is an optimal O_2/He ratio in the inactivation of bacteria and biomolecules when radiated by using the plasmas produced in a helium oxygen mixture.展开更多
目的探讨氦氧机械通气联合乌司他丁对盐酸诱导兔急性肺损伤(ALI)的影响。方法将40只健康新西兰兔子随机分为生理盐水对照组(N组)、ALI模型组(M组)、氦氧机械通气治疗组(H组)、乌司他丁治疗组(U组)和氦氧机械通气联合乌司他丁治疗组(H+U...目的探讨氦氧机械通气联合乌司他丁对盐酸诱导兔急性肺损伤(ALI)的影响。方法将40只健康新西兰兔子随机分为生理盐水对照组(N组)、ALI模型组(M组)、氦氧机械通气治疗组(H组)、乌司他丁治疗组(U组)和氦氧机械通气联合乌司他丁治疗组(H+U组)各8只。5组均给予气管切开、机械通气,除了N组外,余各组均气管内滴注盐酸建立ALI模型。模型建立后,N、M组腹腔注射生理盐水,调整吸入氧浓度(FiO_2)为50%;H组给予氦氧通气、腹腔注射生理盐水;U组腹腔注射乌司他丁,调整FiO_2为50%;H+U组给予氦氧通气、腹腔注射乌司他丁。于气管插管后即刻、模型建立后即刻、治疗后4 h记录各组兔子的气道峰压、胸肺总顺应性及PaO_2。治疗4 h后处死兔子,在光学显微镜下观察肺组织的病理学改变,检测肺组织髓过氧化物酶(MPO)含量及细胞凋亡指数(AI)。结果 (1)5组间气道峰压比较,差异有统计学意义(P<0.05),治疗4 h后H组及H+U组的气道峰压较前明显降低,且均低于其余3组。(2)5组间胸肺总顺应性比较,差异有统计学意义(P<0.05),治疗后4 h H组及H+U组的胸肺总顺应性较前升高,且均高于其余3组。(3)5组间PaO_2比较,差异有统计学意义(P<0.05),治疗后4 h M组、H组明显低于N组,但U组及U+H组接近N组水平。(4)治疗4 h后,其余4组MPO水平均高于N组(P<0.05),U组和H+U组的MPO活性较M组和H组明显降低(P<0.05)。(5)M组和H组的AI均高于N组(P<0.05),M组和H组间比较,差异无统计学意义(P>0.05);而U组和H+U组的AI均低于M组及H组(P<0.05),U组和H+U组间比较,差异无统计学意义(P>0.05)。结论氦氧机械通气联合乌司他丁能够通过降低气道峰压、改善氧合及胸肺总顺应性、抑制炎性细胞聚集及激活、减少肺组织细胞凋亡等途径对盐酸诱导的兔急性肺损伤有一定的保护作用。展开更多
基金supported by the Fundamental Research Funds of Shandong University,China(No.2016JC016)
文摘In this work the effects of O_2 concentration on the pulsed dielectric barrier discharge in helium-oxygen mixture at atmospheric pressure have been numerically researched by using a one-dimensional fluid model in conjunction with the chosen key species and chemical reactions.The reliability of the used model has been examined by comparing the calculated discharge current with the reported experiments. The present work presents the following significant results. The dominative positive and negative particles are He_2~＋ and O_2^-, respectively, the densities of the reactive oxygen species（ROS） get their maxima nearly at the central position of the gap, and the density of the ground state O is highest in the ROS. The increase of O_2 concentration results in increasingly weak discharge and the time lag of the ignition. For O_2 concentrations below 1.1%,the density of O is much higher than other species, the averaged dissipated power density presents an evident increase for small O_2 concentration and then the increase becomes weak. In particular,the total density of the reactive oxygen species reaches its maximums at the O_2 concentration of about 0.5%. This characteristic further convinces the experimental observation that the O_2 concentration of 0.5% is an optimal O_2/He ratio in the inactivation of bacteria and biomolecules when radiated by using the plasmas produced in a helium oxygen mixture.
文摘目的探讨氦氧机械通气联合乌司他丁对盐酸诱导兔急性肺损伤(ALI)的影响。方法将40只健康新西兰兔子随机分为生理盐水对照组(N组)、ALI模型组(M组)、氦氧机械通气治疗组(H组)、乌司他丁治疗组(U组)和氦氧机械通气联合乌司他丁治疗组(H+U组)各8只。5组均给予气管切开、机械通气,除了N组外,余各组均气管内滴注盐酸建立ALI模型。模型建立后,N、M组腹腔注射生理盐水,调整吸入氧浓度(FiO_2)为50%;H组给予氦氧通气、腹腔注射生理盐水;U组腹腔注射乌司他丁,调整FiO_2为50%;H+U组给予氦氧通气、腹腔注射乌司他丁。于气管插管后即刻、模型建立后即刻、治疗后4 h记录各组兔子的气道峰压、胸肺总顺应性及PaO_2。治疗4 h后处死兔子,在光学显微镜下观察肺组织的病理学改变,检测肺组织髓过氧化物酶(MPO)含量及细胞凋亡指数(AI)。结果 (1)5组间气道峰压比较,差异有统计学意义(P<0.05),治疗4 h后H组及H+U组的气道峰压较前明显降低,且均低于其余3组。(2)5组间胸肺总顺应性比较,差异有统计学意义(P<0.05),治疗后4 h H组及H+U组的胸肺总顺应性较前升高,且均高于其余3组。(3)5组间PaO_2比较,差异有统计学意义(P<0.05),治疗后4 h M组、H组明显低于N组,但U组及U+H组接近N组水平。(4)治疗4 h后,其余4组MPO水平均高于N组(P<0.05),U组和H+U组的MPO活性较M组和H组明显降低(P<0.05)。(5)M组和H组的AI均高于N组(P<0.05),M组和H组间比较,差异无统计学意义(P>0.05);而U组和H+U组的AI均低于M组及H组(P<0.05),U组和H+U组间比较,差异无统计学意义(P>0.05)。结论氦氧机械通气联合乌司他丁能够通过降低气道峰压、改善氧合及胸肺总顺应性、抑制炎性细胞聚集及激活、减少肺组织细胞凋亡等途径对盐酸诱导的兔急性肺损伤有一定的保护作用。
