The Meishan section of China has been confirmed as the ＂Global Stratotype Section and Point＂ of the P/T boundary. In the section, the authors found several types of iron grains, including pyrite, pure iron grains an...The Meishan section of China has been confirmed as the ＂Global Stratotype Section and Point＂ of the P/T boundary. In the section, the authors found several types of iron grains, including pyrite, pure iron grains and goethite. From the research of macro minerals, it is easy to find that the grains rich in iron appear from the bottom of the event layer of the section. In other words, it is probably residue of the geochemical catastrophe of that time. Therefore, it is important to trace the source of these iron grains and their relationships, which probably provides evidence for volcanic eruption or impact-volcanoes and has directive significance to the crisis during the P/T transitional period. Through the study of the characterization and relationships of these iron grains, the authors make a preliminary discussion on the P/T mass extinction.展开更多
目的:探究艾司氯胺酮用于剖宫产术后静脉镇痛泵中对产妇产后抑郁及调节性T细胞(regulatory T cell,Treg细胞)数量比例、IL-10表达水平的影响。方法:选择剖宫产产妇80例,随机分为艾司氯胺酮组(E组)和对照组(C组),各40例。两组术后均使用...目的:探究艾司氯胺酮用于剖宫产术后静脉镇痛泵中对产妇产后抑郁及调节性T细胞(regulatory T cell,Treg细胞)数量比例、IL-10表达水平的影响。方法:选择剖宫产产妇80例,随机分为艾司氯胺酮组(E组)和对照组(C组),各40例。两组术后均使用静脉自控镇痛泵,E组泵中加入0.4 mg/kg艾司氯胺酮,C组未加。使用爱丁堡产后抑郁量表(Edinburgh postnatal depression score,EPDS)评估产妇抑郁程度,计算两组产妇产后第3天和第42天抑郁发生率。流式细胞术检测产妇入院时、产后第3天和第42天外周血中Treg细胞数量比例,ELISA检测IL-10的表达水平。采用Pearson直线相关性分析EPDS评分与Treg细胞数量比例、IL-10表达水平的相关性。结果:产后第3天和第42天,E组产后EPDS评分和抑郁症发生率明显低于C组(P<0.05),C组Treg细胞数量比例和IL-10表达水平明显低于入院时(P<0.05);E组Treg细胞数量比例和IL-10表达水平明显高于C组(P<0.05);EPDS评分与Treg细胞数量比例呈负相关(r=-0.505、-0.503,P<0.05),且EPDS评分与IL-10表达水平呈负相关(r=-0.524、-0.511,P<0.05)。结论:艾司氯胺酮可能通过有效调节Treg细胞数量比例,促使分泌IL-10来减轻炎症反应,从而有助于预防或减轻产后抑郁。展开更多
For the purpose of inventing a new seismic retrofitting method for the reinforced high strength concrete (HSC) T-section beam using carbon fiber reinforced polymer (CFRP) sheet, three series, a total of twelve T-secti...For the purpose of inventing a new seismic retrofitting method for the reinforced high strength concrete (HSC) T-section beam using carbon fiber reinforced polymer (CFRP) sheet, three series, a total of twelve T-section beams with nine specimens confined by CFRP sheet in the plastic zone and three control beams were conducted up to failure under four-point bending test. The effectiveness of confining CFRP sheet on improving the flexural ductility of unstrengthened T-section beams was studied. The parameters such as the width and the thickness of CFRP sheet and the type of T-section were analyzed. The experimental results show that ductility and rotation capacity of plastic hinge can be improved by the confinement of CFRP sheet, and the ductility indices increase with the increment of width and thickness of CFRP sheet. A plastic rotation model considering the width of CFRP sheet and the effect of flange of T-section beam is proposed on the basis of the model of BAKER, and the test results show a good agreement with the perdicted results. The relevant construction suggestions for seismic retrofitting design of beam-slabs system in cast-in-place framework structure are presented.展开更多
Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-r...Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.展开更多
Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of ...Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of 19,140 attenuation factors t*is obtained by fitting the high-frequency attenuation of S-wave spectra with a genetic algorithm. The spatial distribution of Q_S is determined by inverting the t*data with seismic tomography. The results show that the average Q0 in eastern Tianshan is 520,and there is a significant correlation between the Q_S value distribution or attenuation characteristics it disclosed and the surface structure of the study area. The Q_S value is lower in the intersection area of the mountain basin which is located on the north and south sides of the Tianshan Mountains,and the high Q_S distribution is more concentrated inside the Tianshan orogenic belt. The M≥6. 0 earthquakes have been basically located in the Low-Q_S region since 1900. 24 high heat flow points in eastern Tianshan are located at the north and south of Tianshan Mountains where low Q_S exists,indicating a negative correlation. In addition,there is a positive correlation between the velocity structure and the attenuation structure in the study area,which reflects the consistency of the 2-D attenuation structure with the velocity structure and the two-dimensional density structure.展开更多
Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a p...Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a primary reference hospital at Puebla City, Mexico. Sample: 396 women requiring CS signed informed consent and were randomly allocated to the post-placental application of LNG-IUS (198) or Copper T 380 A (198). Methods: Follow up visits at 6 weeks, and 6 and 12 months were performed. Main Outcomes Measures: IUDs expulsion, maternal and babies’ health conditions, breastfeeding and menstrual patterns, adverse effects and pregnancies. Differences between groups were analyzed by Fisher and X2 tests, Odds ratios, relative risk and 95% confidence limits, as appropriate. Results: After one year of follow up, no pregnancies were reported. The IUD expulsion rate was 4.5% in each group. LNG-IUS users had a higher incidence of amenorrhea (OR 2.5 95% CI 2.2 - 3) and menstrual patterns significantly brief and lighter than Copper T 380 A (p < 0.001) with lower incidence of dysmenorrhea (OR 0.1 95% CI 0.04 - 0.2). No detrimental effects of LNG-IUS on breastfeeding was observed and interestingly babies weights of LNG-IUS users was slightly above the average for age compared with Copper T 380 A users. This was probably related with a major proportion of women with normal ferritin serum levels (94% vs 68%) leading to better mother’s general condition. Conclusions: LNG-IUS inserted during CS provides high efficacy contraception with additional benefits, mainly reducing menstrual bleeding and doing so, faster recovery of ferrous homeostasis after CS.展开更多
On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae...On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.展开更多
基金This research was supported by the National Natural Science Foundation of China （Nos. 40232025 40072055+1 种基金 40572020） the Research Fund for the Doctoral Program of Higher Education （No. 20040290005）.
文摘The Meishan section of China has been confirmed as the ＂Global Stratotype Section and Point＂ of the P/T boundary. In the section, the authors found several types of iron grains, including pyrite, pure iron grains and goethite. From the research of macro minerals, it is easy to find that the grains rich in iron appear from the bottom of the event layer of the section. In other words, it is probably residue of the geochemical catastrophe of that time. Therefore, it is important to trace the source of these iron grains and their relationships, which probably provides evidence for volcanic eruption or impact-volcanoes and has directive significance to the crisis during the P/T transitional period. Through the study of the characterization and relationships of these iron grains, the authors make a preliminary discussion on the P/T mass extinction.
基金Project(51121005) supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of ChinaProject(50878035) supported by the National Natural Science Foundation of China
文摘For the purpose of inventing a new seismic retrofitting method for the reinforced high strength concrete (HSC) T-section beam using carbon fiber reinforced polymer (CFRP) sheet, three series, a total of twelve T-section beams with nine specimens confined by CFRP sheet in the plastic zone and three control beams were conducted up to failure under four-point bending test. The effectiveness of confining CFRP sheet on improving the flexural ductility of unstrengthened T-section beams was studied. The parameters such as the width and the thickness of CFRP sheet and the type of T-section were analyzed. The experimental results show that ductility and rotation capacity of plastic hinge can be improved by the confinement of CFRP sheet, and the ductility indices increase with the increment of width and thickness of CFRP sheet. A plastic rotation model considering the width of CFRP sheet and the effect of flange of T-section beam is proposed on the basis of the model of BAKER, and the test results show a good agreement with the perdicted results. The relevant construction suggestions for seismic retrofitting design of beam-slabs system in cast-in-place framework structure are presented.
基金National Natural Science Foundation of China(No.50471025)Natural Science Foundation of Liaoning Province (No.20052028).
文摘Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.
基金jointly funded by the Contract Oriented Work Task for Seismic Situation in 2017(2017010104)Science for Earthquake Resilience(XH17041Y)Fund of Earthquake Agency of Xinjiang Uygur Autonomous Region(201401)
文摘Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of 19,140 attenuation factors t*is obtained by fitting the high-frequency attenuation of S-wave spectra with a genetic algorithm. The spatial distribution of Q_S is determined by inverting the t*data with seismic tomography. The results show that the average Q0 in eastern Tianshan is 520,and there is a significant correlation between the Q_S value distribution or attenuation characteristics it disclosed and the surface structure of the study area. The Q_S value is lower in the intersection area of the mountain basin which is located on the north and south sides of the Tianshan Mountains,and the high Q_S distribution is more concentrated inside the Tianshan orogenic belt. The M≥6. 0 earthquakes have been basically located in the Low-Q_S region since 1900. 24 high heat flow points in eastern Tianshan are located at the north and south of Tianshan Mountains where low Q_S exists,indicating a negative correlation. In addition,there is a positive correlation between the velocity structure and the attenuation structure in the study area,which reflects the consistency of the 2-D attenuation structure with the velocity structure and the two-dimensional density structure.
文摘Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a primary reference hospital at Puebla City, Mexico. Sample: 396 women requiring CS signed informed consent and were randomly allocated to the post-placental application of LNG-IUS (198) or Copper T 380 A (198). Methods: Follow up visits at 6 weeks, and 6 and 12 months were performed. Main Outcomes Measures: IUDs expulsion, maternal and babies’ health conditions, breastfeeding and menstrual patterns, adverse effects and pregnancies. Differences between groups were analyzed by Fisher and X2 tests, Odds ratios, relative risk and 95% confidence limits, as appropriate. Results: After one year of follow up, no pregnancies were reported. The IUD expulsion rate was 4.5% in each group. LNG-IUS users had a higher incidence of amenorrhea (OR 2.5 95% CI 2.2 - 3) and menstrual patterns significantly brief and lighter than Copper T 380 A (p < 0.001) with lower incidence of dysmenorrhea (OR 0.1 95% CI 0.04 - 0.2). No detrimental effects of LNG-IUS on breastfeeding was observed and interestingly babies weights of LNG-IUS users was slightly above the average for age compared with Copper T 380 A users. This was probably related with a major proportion of women with normal ferritin serum levels (94% vs 68%) leading to better mother’s general condition. Conclusions: LNG-IUS inserted during CS provides high efficacy contraception with additional benefits, mainly reducing menstrual bleeding and doing so, faster recovery of ferrous homeostasis after CS.
文摘On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.
