目的研究不同基因型Na-K-2Cl联合转运子1(NKCC1)小鼠的耳蜗和前庭器官的超微形态特点及其与听觉平衡功能的关系。方法采用电子显微镜对NKCC1+/+野生型鼠、NKCC1+/-杂合子鼠和NKCC1-/-基因敲除鼠的耳蜗基底膜和前庭椭圆囊进行观察,并应...目的研究不同基因型Na-K-2Cl联合转运子1(NKCC1)小鼠的耳蜗和前庭器官的超微形态特点及其与听觉平衡功能的关系。方法采用电子显微镜对NKCC1+/+野生型鼠、NKCC1+/-杂合子鼠和NKCC1-/-基因敲除鼠的耳蜗基底膜和前庭椭圆囊进行观察,并应用听觉脑干反应(ABR)检测各基因型鼠的听力和观察平衡表现。结果电镜观察显示NKCC1-/-鼠的边缘细胞体积明显缩小,边缘细胞与中间细胞之间空隙扩大成空泡样,并可见前庭膜贴附于边缘细胞的顶膜边缘上。NKCC1-/-鼠外毛细胞呈现为点状缺失,椭圆囊毛细胞仅有少许残留。NKCC1+/+鼠听力和平衡正常,ABR检测的短声阈值为23.13±3.78(dB SPL);NKCC1+/-鼠听力低于NKCC1+/+鼠,ABR短声阈值为38.49±12.29(dB SPL)。NKCC1+/+和NKCC1+/-鼠ABR的阈值在各个频率的差异均有极显著性意义(均P<0.01)。NKCC1-/-鼠呈现全聋并有平衡失调,ABR的各个频率在100 dB SPL均无反应。结论NKCC1基因在内耳表达的不同可以影响小鼠的听觉平衡功能并导致内耳形态改变;内耳形态改变也可作为基因缺失小鼠听觉平衡的形态学基础。展开更多
目的观察豚鼠耳蜗自噬相关蛋白beclin1和LC3、Na^(+-)K^(+-)2Cl^-联合转运体(NKCC1)m RNA、内皮素(ET)表达与耳蜗庆大霉素(GM)损伤关系及盐酸椒苯酮胺(PPTA)对损伤的保护作用及其机制。方法将60只豚鼠随机分成对照组、模型组、同期治疗...目的观察豚鼠耳蜗自噬相关蛋白beclin1和LC3、Na^(+-)K^(+-)2Cl^-联合转运体(NKCC1)m RNA、内皮素(ET)表达与耳蜗庆大霉素(GM)损伤关系及盐酸椒苯酮胺(PPTA)对损伤的保护作用及其机制。方法将60只豚鼠随机分成对照组、模型组、同期治疗组、造模后对照组、后期治疗组。对照组给NS+人工外淋巴液、模型组给GM+人工外淋巴液、治疗组给GM+PPTA(均连续给药7 d),造模后对照组及后期治疗组均连续注射GM 7 d后,再分别行人工外淋巴液及PPTA连续注入7 d。所有豚鼠给药前均手术行听泡置管,NS及GM(160 mg·kg^(-1)·d^(-1))采用腹腔注射,人工外淋巴液及PPTA采用听泡注入。各组豚鼠完成给药后ABR测试分析听力,检测beclin1和LC3、NKCC1 m RNA及ET-1的表达。结果模型组、造模后对照组的ABR结果差异无统计学意义(P>0.05),但两者均明显高于其余3组(P<0.05),同期治疗组豚鼠ABR阈值明显低于后期治疗组(P<0.05);模型组LC3Ⅱ及Beclin1的表达量较其余4组明显升高,后期治疗组LC3Ⅱ及Beclin1的表达量较造模后对照组降低;模型组NKCC1 m RNA表达较其余4组明显升高(P<0.05),后期治疗组NKCC1 m RNA表达明显低于造模后对照组(P<0.05)。模型组各部位ET-1表达较其余4组明显增高,对照组各部位ET-1表达低于其余4组,后期治疗组各部位ET-1表达较造模后对照组降低。结论 PPTA可抑制耳蜗细胞自噬、NKCC1、ET-1的表达,从而对耳蜗庆大霉素损伤起到保护作用;PPTA早期对抗庆大霉素耳蜗损伤效果更优,提示GM可能对听觉细胞产生不可逆损伤。展开更多
In this paper, an efficient methodology for synthesizing the indirect work exchange networks(WEN) considering isothermal process and adiabatic process respectively based on transshipment model is first proposed. In co...In this paper, an efficient methodology for synthesizing the indirect work exchange networks(WEN) considering isothermal process and adiabatic process respectively based on transshipment model is first proposed. In contrast with superstructure method, the transshipment model is easier to obtain the minimum utility consumption taken as the objective function and more convenient for us to attain the optimal network configuration for further minimizing the number of units. Different from division of temperature intervals in heat exchange networks,different pressure intervals are gained according to the maximum compression/expansion ratio in consideration of operating principles of indirect work exchangers and the characteristics of no pressure constraints for stream matches. The presented approach for WEN synthesis is a linear programming model applied to the isothermal process, but for indirect work exchange networks with adiabatic process, a nonlinear programming model needs establishing. Additionally, temperatures should be regarded as decision variables limited to the range between inlet and outlet temperatures in each sub-network. The constructed transshipment model can be solved first to get the minimum utility consumption and further to determine the minimum number of units by merging the adjacent pressure intervals on the basis of the proposed merging methods, which is proved to be effective through exergy analysis at the level of units structures. Finally, two cases are calculated to confirm it is dramatically feasible and effective that the optimal WEN configuration can be gained by the proposed method.展开更多
This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied...This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied to present the relationship of angular velocities of input shaft and output shaft. The result shows that when the angle between intersecting shafts changes from 0 to 135°, the angular velocity is maintained constant. This new result completely matches with analysis from kinematic simulation of this mechanism. The obtained result is an important base to solve dynamic problem in order to develop the applicability of this joint in reality.展开更多
The railway transport is one of the main types of communications in the world. Analysis of service conditions of the most critical elements of the railway transport rolling stock （mils, wheels and tyres） shows that ...The railway transport is one of the main types of communications in the world. Analysis of service conditions of the most critical elements of the railway transport rolling stock （mils, wheels and tyres） shows that one of the main factors determining their reliability and service life is the structural-phase state of steel, which is formed in the process of its producing. Complication of service conditions leads to the more severe requirements, specified by the consumers, where the high level of strength and hardness should be combined with high values of ductility and toughness. Realization of these requirements is possible only at the integrated approach to the improvement of technology of their production on the basis of profound knowledge in kinetics of austenite decay processes of structure formation and its contribution to the mechanical properties. With the formation of mainly bainite-martensite structures in the HAZ （heat-affected zone） metal of welded joints of these steels and saturation of this region with diffusive hydrogen their susceptibility to the cold cracking is increased. In this connection this work presents the results of investigations of effect of the WTC （welding thermal cycles） on the nature of structural transformations, hardness, static strength and resistance to the formation of cold cracks in HAZ metal of high-strength carbon rail steel M76. For this purpose, the structure and kinetics of transformation of an overcooled austenite was studied using the advanced methods of physical materials science by the modeling of phase transformations in the Gleeble 3800 unit. It was found that the cause of reduction in mechanical properties of welded joints of steel M76 is the formation of regions with a completely martensite structure in the amount of up to 5%. Results of investigations will be applied for the optimizing the technology and conditions of FBW of the advanced rail steels. 10 Ref., 4 Tables, 11 Figures.展开更多
文摘目的研究不同基因型Na-K-2Cl联合转运子1(NKCC1)小鼠的耳蜗和前庭器官的超微形态特点及其与听觉平衡功能的关系。方法采用电子显微镜对NKCC1+/+野生型鼠、NKCC1+/-杂合子鼠和NKCC1-/-基因敲除鼠的耳蜗基底膜和前庭椭圆囊进行观察,并应用听觉脑干反应(ABR)检测各基因型鼠的听力和观察平衡表现。结果电镜观察显示NKCC1-/-鼠的边缘细胞体积明显缩小,边缘细胞与中间细胞之间空隙扩大成空泡样,并可见前庭膜贴附于边缘细胞的顶膜边缘上。NKCC1-/-鼠外毛细胞呈现为点状缺失,椭圆囊毛细胞仅有少许残留。NKCC1+/+鼠听力和平衡正常,ABR检测的短声阈值为23.13±3.78(dB SPL);NKCC1+/-鼠听力低于NKCC1+/+鼠,ABR短声阈值为38.49±12.29(dB SPL)。NKCC1+/+和NKCC1+/-鼠ABR的阈值在各个频率的差异均有极显著性意义(均P<0.01)。NKCC1-/-鼠呈现全聋并有平衡失调,ABR的各个频率在100 dB SPL均无反应。结论NKCC1基因在内耳表达的不同可以影响小鼠的听觉平衡功能并导致内耳形态改变;内耳形态改变也可作为基因缺失小鼠听觉平衡的形态学基础。
文摘目的观察豚鼠耳蜗自噬相关蛋白beclin1和LC3、Na^(+-)K^(+-)2Cl^-联合转运体(NKCC1)m RNA、内皮素(ET)表达与耳蜗庆大霉素(GM)损伤关系及盐酸椒苯酮胺(PPTA)对损伤的保护作用及其机制。方法将60只豚鼠随机分成对照组、模型组、同期治疗组、造模后对照组、后期治疗组。对照组给NS+人工外淋巴液、模型组给GM+人工外淋巴液、治疗组给GM+PPTA(均连续给药7 d),造模后对照组及后期治疗组均连续注射GM 7 d后,再分别行人工外淋巴液及PPTA连续注入7 d。所有豚鼠给药前均手术行听泡置管,NS及GM(160 mg·kg^(-1)·d^(-1))采用腹腔注射,人工外淋巴液及PPTA采用听泡注入。各组豚鼠完成给药后ABR测试分析听力,检测beclin1和LC3、NKCC1 m RNA及ET-1的表达。结果模型组、造模后对照组的ABR结果差异无统计学意义(P>0.05),但两者均明显高于其余3组(P<0.05),同期治疗组豚鼠ABR阈值明显低于后期治疗组(P<0.05);模型组LC3Ⅱ及Beclin1的表达量较其余4组明显升高,后期治疗组LC3Ⅱ及Beclin1的表达量较造模后对照组降低;模型组NKCC1 m RNA表达较其余4组明显升高(P<0.05),后期治疗组NKCC1 m RNA表达明显低于造模后对照组(P<0.05)。模型组各部位ET-1表达较其余4组明显增高,对照组各部位ET-1表达低于其余4组,后期治疗组各部位ET-1表达较造模后对照组降低。结论 PPTA可抑制耳蜗细胞自噬、NKCC1、ET-1的表达,从而对耳蜗庆大霉素损伤起到保护作用;PPTA早期对抗庆大霉素耳蜗损伤效果更优,提示GM可能对听觉细胞产生不可逆损伤。
基金Supported by the National Natural Science Foundation of China(21576036 and 21776035)
文摘In this paper, an efficient methodology for synthesizing the indirect work exchange networks(WEN) considering isothermal process and adiabatic process respectively based on transshipment model is first proposed. In contrast with superstructure method, the transshipment model is easier to obtain the minimum utility consumption taken as the objective function and more convenient for us to attain the optimal network configuration for further minimizing the number of units. Different from division of temperature intervals in heat exchange networks,different pressure intervals are gained according to the maximum compression/expansion ratio in consideration of operating principles of indirect work exchangers and the characteristics of no pressure constraints for stream matches. The presented approach for WEN synthesis is a linear programming model applied to the isothermal process, but for indirect work exchange networks with adiabatic process, a nonlinear programming model needs establishing. Additionally, temperatures should be regarded as decision variables limited to the range between inlet and outlet temperatures in each sub-network. The constructed transshipment model can be solved first to get the minimum utility consumption and further to determine the minimum number of units by merging the adjacent pressure intervals on the basis of the proposed merging methods, which is proved to be effective through exergy analysis at the level of units structures. Finally, two cases are calculated to confirm it is dramatically feasible and effective that the optimal WEN configuration can be gained by the proposed method.
文摘This paper has been done on study kinematic problem of Persian joint in a general way. In this study, instead of using simulation analysis method as in the previous researches, the 3D rotation matrix method is applied to present the relationship of angular velocities of input shaft and output shaft. The result shows that when the angle between intersecting shafts changes from 0 to 135°, the angular velocity is maintained constant. This new result completely matches with analysis from kinematic simulation of this mechanism. The obtained result is an important base to solve dynamic problem in order to develop the applicability of this joint in reality.
文摘The railway transport is one of the main types of communications in the world. Analysis of service conditions of the most critical elements of the railway transport rolling stock （mils, wheels and tyres） shows that one of the main factors determining their reliability and service life is the structural-phase state of steel, which is formed in the process of its producing. Complication of service conditions leads to the more severe requirements, specified by the consumers, where the high level of strength and hardness should be combined with high values of ductility and toughness. Realization of these requirements is possible only at the integrated approach to the improvement of technology of their production on the basis of profound knowledge in kinetics of austenite decay processes of structure formation and its contribution to the mechanical properties. With the formation of mainly bainite-martensite structures in the HAZ （heat-affected zone） metal of welded joints of these steels and saturation of this region with diffusive hydrogen their susceptibility to the cold cracking is increased. In this connection this work presents the results of investigations of effect of the WTC （welding thermal cycles） on the nature of structural transformations, hardness, static strength and resistance to the formation of cold cracks in HAZ metal of high-strength carbon rail steel M76. For this purpose, the structure and kinetics of transformation of an overcooled austenite was studied using the advanced methods of physical materials science by the modeling of phase transformations in the Gleeble 3800 unit. It was found that the cause of reduction in mechanical properties of welded joints of steel M76 is the formation of regions with a completely martensite structure in the amount of up to 5%. Results of investigations will be applied for the optimizing the technology and conditions of FBW of the advanced rail steels. 10 Ref., 4 Tables, 11 Figures.
