This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength r...This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements （optical and pneumatic）.展开更多
[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning...[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.展开更多
Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptati...Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptation in the natural habitats of common reed （Phragmites communis Trin.） contrasted considerably among three different ecotypes： dune reed （DR）, Gobi salt reed （GSR） and swamp reed （SR）. The main objective of the present study is to determine the adapting characteristics of morphology, anatomy and physiological responses of thin roots in DR, GSR and SR. The results show that root length density was higher in SR and few root hairs were observed in DR. Cross-section anatomical features show that each ecotype has an endodermis and exodermis, while cortex thickness and proportion of root cortical aerenchyma and stele in root structure varied among the three ecotypes. The stele and xylem share a larger area in DR compared to GSR and SR. GSR has a large proportion of the cortex with radialized distribution of aerenchyma cells spacing, and the cortex has a peripheral, mechanically stiff ring in the exodermis. SEM and TEM microscope images show that GSR has a scle- renchyma ring with high lignification in the exodermis. The physio-chemical parameters show that GSR had a higher level of stress tolerance than DR. These findings indicate that developed water-absorbing tissues were largely distributed in the root structure of DR, and a main framework with supporting function spacing with aerenchyma was dominant in GSR in the long term adaptation to their natural habitats, respectively.展开更多
目的:调查胃肠道恶性肿瘤手术患者营养状况,并探讨其影响因素。方法:横断面调查2021年01月至2022年05月入住合肥市某三级甲等医院胃肠外科560例行胃肠道恶性肿瘤根治术患者的相关资料,应用GLIM标准诊断营养不良,统计营养不良发生现况并...目的:调查胃肠道恶性肿瘤手术患者营养状况,并探讨其影响因素。方法:横断面调查2021年01月至2022年05月入住合肥市某三级甲等医院胃肠外科560例行胃肠道恶性肿瘤根治术患者的相关资料,应用GLIM标准诊断营养不良,统计营养不良发生现况并分析其影响因素。结果:560例行胃肠道恶性肿瘤根治术患者中,营养不良的发生率为28.93%(162/560),其中重度营养不良的发生率为7.68%(43/560)。胃癌患者营养不良发生率为39.09%(95/243),结直肠癌患者营养不良发生率为21.14%(67/317)。Logistic回归分析显示:肿瘤类型(OR=3.192)、肿瘤分期、饮食教育(OR=2.821)、体质量指数(body mass index,BMI)(OR=0.709)、血清白蛋白浓度(OR=0.491)、血红蛋白浓度(OR=0.190)是胃肠道恶性肿瘤手术患者发生营养不良的影响因素(P<0.05)。结论:胃肠道恶性肿瘤手术患者易发生营养不良,且胃癌患者高于结直肠癌患者。肿瘤分期越晚及未接受正规饮食教育的患者营养不良发生率更高。入院BMI、血清白蛋白浓度、血红蛋白浓度下降是胃肠道恶性肿瘤手术患者发生营养不良的危险因素。建议临床医护人员应关注胃癌、晚期肿瘤、低蛋白血症及贫血的手术患者,及时给予个案化营养干预提高术前营养状况,改善临床结局。展开更多
基金the Technology Agency of the Czech Republic,which supported this research under grants No.TA03020277 and TH02020057Institutional support RVO61388998
文摘This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements （optical and pneumatic）.
基金Supported by National Natural Science Foundation of China(81001700)Project of Sichuan Provincial Education Department(11ZB227,11ZB124)Research Project for the Application Foundation of Sichuan Provincial Science and Technology Department(2012JY0081)
文摘[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.
基金financially supported by the State Key Development Program for Basic Research of China(973 Program,Grant No.2013CB429904)the National Natural Science Foundation of China(Grant No.91125029)
文摘Reeds are widely distributed in drought and high salt conditions of northwestern China. Leaf epidermal micromorphology, anatomy, chloroplast ultrastructure and physio-chemical characteristics due to long-term adaptation in the natural habitats of common reed （Phragmites communis Trin.） contrasted considerably among three different ecotypes： dune reed （DR）, Gobi salt reed （GSR） and swamp reed （SR）. The main objective of the present study is to determine the adapting characteristics of morphology, anatomy and physiological responses of thin roots in DR, GSR and SR. The results show that root length density was higher in SR and few root hairs were observed in DR. Cross-section anatomical features show that each ecotype has an endodermis and exodermis, while cortex thickness and proportion of root cortical aerenchyma and stele in root structure varied among the three ecotypes. The stele and xylem share a larger area in DR compared to GSR and SR. GSR has a large proportion of the cortex with radialized distribution of aerenchyma cells spacing, and the cortex has a peripheral, mechanically stiff ring in the exodermis. SEM and TEM microscope images show that GSR has a scle- renchyma ring with high lignification in the exodermis. The physio-chemical parameters show that GSR had a higher level of stress tolerance than DR. These findings indicate that developed water-absorbing tissues were largely distributed in the root structure of DR, and a main framework with supporting function spacing with aerenchyma was dominant in GSR in the long term adaptation to their natural habitats, respectively.
文摘目的:调查胃肠道恶性肿瘤手术患者营养状况,并探讨其影响因素。方法:横断面调查2021年01月至2022年05月入住合肥市某三级甲等医院胃肠外科560例行胃肠道恶性肿瘤根治术患者的相关资料,应用GLIM标准诊断营养不良,统计营养不良发生现况并分析其影响因素。结果:560例行胃肠道恶性肿瘤根治术患者中,营养不良的发生率为28.93%(162/560),其中重度营养不良的发生率为7.68%(43/560)。胃癌患者营养不良发生率为39.09%(95/243),结直肠癌患者营养不良发生率为21.14%(67/317)。Logistic回归分析显示:肿瘤类型(OR=3.192)、肿瘤分期、饮食教育(OR=2.821)、体质量指数(body mass index,BMI)(OR=0.709)、血清白蛋白浓度(OR=0.491)、血红蛋白浓度(OR=0.190)是胃肠道恶性肿瘤手术患者发生营养不良的影响因素(P<0.05)。结论:胃肠道恶性肿瘤手术患者易发生营养不良,且胃癌患者高于结直肠癌患者。肿瘤分期越晚及未接受正规饮食教育的患者营养不良发生率更高。入院BMI、血清白蛋白浓度、血红蛋白浓度下降是胃肠道恶性肿瘤手术患者发生营养不良的危险因素。建议临床医护人员应关注胃癌、晚期肿瘤、低蛋白血症及贫血的手术患者,及时给予个案化营养干预提高术前营养状况,改善临床结局。
