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Bird specimen number linked with species trait and climate niche breadth
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作者 Xiaoyu Duan Xiongwei Huang +4 位作者 Jingya Zhang Shuo Lv Gang Song Yanping Wang Gang Feng 《Avian Research》 SCIE CSCD 2024年第1期108-115,共8页
Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity re... Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity research and conservation.However,there are few systematic studies on the patterns and drivers of bird specimen number at regional scales.This study is the first attempt to examine the relationships between bird specimen number and species traits as well as climate niche breadth in China,aiming to answer two questions:1)how do species’temperature niche breadth and precipitation niche breadth influence specimen number?2)which trait is most associated with bird specimen number?The associations between bird specimen number and explanatory variables were examined using ordinary least squares,generalized linear models,phylogenetic generalized linear mixed models,and multiple comparisons.The results showed that Muscicapidae was the family with the highest specimen number,and Passeriformes was the order with the highest specimen number.Bird specimen number significantly increased with larger temperature niche breadth and precipitation niche breadth.Specimen number was also positively associated with geographic range size,habitat specificity,hunting vulnerability and clutch size,but negatively associated with body size.These findings suggest that future bird specimen collection should pay more attention to birds with limited ecological niches,large body sizes,and small clutch sizes.This research enhances the use of bird specimen data to study and preserve biodiversity. 展开更多
关键词 Biodiversity conservation Biological specimens Bird traits Scientific collection specimen number Temperature and precipitation
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Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China
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作者 Jingya Zhang Cui Xiao +5 位作者 Xiaoyu Duan Xin Gao Hao Zeng Rong'an Dong Gang Feng Keping Ma 《Plant Diversity》 SCIE CAS CSCD 2024年第3期353-361,共9页
Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection... Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate. 展开更多
关键词 Biological specimen Collection preference Dominant plant species Environmental range Geographical range Species traits
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Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen
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作者 Troy Myers Michael A.Sutton +2 位作者 Hubert Schreier Alistair Tofts Sreehari Rajan Kattil 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1263-1298,共36页
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is... To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process. 展开更多
关键词 StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation
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Perioperative outcomes of transvaginal specimen extraction laparoscopic total gastrectomy and conventional laparoscopicassisted total gastrectomy
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作者 Zhi-Cao Zhang Wen-Sheng Wang +5 位作者 Jiang-Hong Chen Yuan-Hang Ma Qi-Fa Luo Yun-Bo Li Yang Yang Dan Ma 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第6期1527-1536,共10页
BACKGROUND Natural orifice specimen extraction surgery(NOSES)has emerged as a promising alternative compared to conventional laparoscopic-assisted total gastrectomy(LATG)for treating gastric cancer(GC).However,evidenc... BACKGROUND Natural orifice specimen extraction surgery(NOSES)has emerged as a promising alternative compared to conventional laparoscopic-assisted total gastrectomy(LATG)for treating gastric cancer(GC).However,evidence regarding the efficacy and safety of NOSES for GC surgery is limited.This study aimed to compare the safety and feasibility,in addition to postoperative complications of NOSES and LATG.METHODS Dual circular staplers were used in Roux-en-Y digestive tract reconstruction for transvaginal specimen extraction LATG,and its outcomes were compared with LATG in a cohort of 51 GC patients with tumor size≤5 cm.The study was conducted from May 2018 to September 2020,and patients were categorized into the NOSES group(n=22)and LATG group(n=29).Perioperative parameters were compared and analyzed,including patient and tumor characteristics,postoperative outcomes,and anastomosis-related complications,postoperative hospital stay,the length of abdominal incision,difference in tumor type,postoperative complications,and postoperative survival.RESULTS Postoperative exhaust time,operation duration,mean postoperative hospital stay,length of abdominal incision,number of specific staplers used,and Brief Illness Perception Questionnaire score were significant in both groups(P<0.01).In the NOSES group,the postoperative time to first flatus,mean postoperative hospital stay,and length of abdominal incision were significantly shorter than those in the LATG group.Patients in the NOSES group had faster postoperative recovery,and achieved abdominal minimally invasive incision that met aesthetic requirements.There were no significant differences in gender,age,tumor type,postoperative complications,and postoperative survival between the two groups.CONCLUSION The application of dual circular staplers in Roux-en-Y digestive tract reconstruction combined with NOSES gastrectomy is safe and convenient.This approach offers better short-term outcomes compared to LATG,while long-term survival rates are comparable to those of conventional laparoscopic surgery. 展开更多
关键词 Gastric cancer Circular stapler Natural orifice specimen extraction surgery Laparoscopic-assisted total gastrectomy
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Application Effect of Feedforward Control in Outpatient Blood Specimen Management
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作者 Meiying Lu 《Journal of Clinical and Nursing Research》 2024年第6期177-183,共7页
Objective:To analyze the application effect of feedforward control in outpatient blood specimen management.Methods:1,200 patients who had their venous blood collected in outpatient phlebotomy room of our hospital'... Objective:To analyze the application effect of feedforward control in outpatient blood specimen management.Methods:1,200 patients who had their venous blood collected in outpatient phlebotomy room of our hospital's outpatient clinic from January 2021 to April 2021 were selected as study subjects and divided into 600 cases in the control group and 600 cases in the observation group.The two groups of patients were compared in terms of their satisfaction with the staff,the efficiency of the nurses and the quality of nursing care,turnaround time before specimen analysis,the rejection rate of the blood specimens,and the time of result reporting.Results:After the implementation of feedforward control,patients'satisfaction with staff,nurses work efficiency and quality of care,turnaround time before specimen analysis,specimen rejection rate,and result reporting time in the observation group were significantly higher than those in the control group(P<0.05).Conclusion:The application of feedforward control in the management of outpatient blood specimens has significant effect,which effectively improves patients'satisfaction,enhances the efficiency of nurses and the quality of nursing care,shortens the turnaround time of specimens before analysis and the reporting time of results,and reduces the rejection rate of specimens. 展开更多
关键词 Feedforward control Venous blood specimen Nursing management Application effect
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Experimental and numerical study on crack propagation in pre-cracked beam specimens under three-point bending 被引量:6
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作者 Hadi Haeri 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第2期430-439,共10页
A simultaneous experimental and numerical study on crack propagation in the pre-cracked beams specimens(concrete-like materials) is carried out using three-point bending flexural test. The crack propagation and coales... A simultaneous experimental and numerical study on crack propagation in the pre-cracked beams specimens(concrete-like materials) is carried out using three-point bending flexural test. The crack propagation and coalescence paths of internal cracks in side beam specimens are experimentally studied by inserting double internal cracks. The effects of crack positions on the fracturing path in the bridge areas of the double cracked beam specimens are also studied. It has been observed that the breaking of concrete-like cracked beams specimens occurs mainly by the propagation of wing cracks emanating from the tips of the pre-existing cracks in the numerical and experimental analyses, respectively. The same specimens are numerically simulated by an indirect boundary element method(IBEM) known as displacement discontinuity method(DDM) using higher displacement discontinuity. These numerical results are compared with the existing experimental results. This comparison illustrates the higher accuracy of the results obtained by the indirect boundary element method by using only a small number of elements compared with the discrete element method(PFC2D code). 展开更多
关键词 double internal cracks concrete-like specimens crack propagation
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Crack growth analysis for rock-like materials with ordered multiple pre-cracks under biaxial compression 被引量:3
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作者 WANG Min CAO Ping +3 位作者 WAN Wen ZHAO Yan-lin LIU Jie LIU Jing-shuo 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第4期866-874,共9页
The pre-burying iron sheets approach was used to prepare rock-like materials with ordered multiple pre-cracks. 60 specimens in total were prepared in these experiments. Through biaxial compression experiments, the inf... The pre-burying iron sheets approach was used to prepare rock-like materials with ordered multiple pre-cracks. 60 specimens in total were prepared in these experiments. Through biaxial compression experiments, the influence of both the number of pre-cracks and pre-cracks angles to crack growth was analyzed. Meanwhile, species of rock bridge failure were summarized, namely, wing crack, secondary shear crack between horizontal pre-cracks and secondary shear crack between vertical pre-cracks. The wing crack plays a significant role in crack growth. Furthermore, fractal dimension was adopted to describe quantitatively the crack growth during the failure process. The results indicate that with the failure of specimens, corresponding fractal dimension for specimen monotonically increases, which indicates that the fractal dimension can be considered to the failure of the specimens quantitatively. 展开更多
关键词 CRACK growth WING CRACK secondary SHEAR CRACK vertical pre-cracks FRACTAL DIMENSION
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Robotic natural orifice specimen extraction surgery I-type F method vs conventional robotic resection for lower rectal cancer 被引量:2
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作者 Fang Tao Dong-Ning Liu +4 位作者 Peng-Hui He Xin Luo Chi-Ying Xu Tai-Yuan Li Jin-Yuan Duan 《World Journal of Gastrointestinal Surgery》 SCIE 2023年第10期2142-2153,共12页
BACKGROUND Robotic resection using the natural orifice specimen extraction surgery I-type F method(R-NOSES I-F)is a novel minimally invasive surgical strategy for the treatment of lower rectal cancer.However,the curre... BACKGROUND Robotic resection using the natural orifice specimen extraction surgery I-type F method(R-NOSES I-F)is a novel minimally invasive surgical strategy for the treatment of lower rectal cancer.However,the current literature on this method is limited to case reports,and further investigation into its safety and feasibility is warranted.AIM To evaluate the safety and feasibility of R-NOSES I-F for the treatment of low rectal cancer.METHODS From September 2018 to February 2022,206 patients diagnosed with low rectal cancer at First Affiliated Hospital of Nanchang University were included in this retrospective analysis.Of these patients,22 underwent R-NOSES I-F surgery(RNOSES I-F group)and 76 underwent conventional robotic-assisted low rectal cancer resection(RLRC group).Clinicopathological data of all patients were collected and analyzed.Postoperative outcomes and prognoses were compared between the two groups.Statistical analysis was performed using SPSS software.RESULTS Patients in the R-NOSES I-F group had a significantly lower visual analog score for pain on postoperative day 1(1.7±0.7 vs 2.2±0.6,P=0.003)and shorter postoperative anal venting time(2.7±0.6 vs 3.5±0.7,P<0.001)than those in the RLRC group.There were no significant differences between the two groups in terms of sex,age,body mass index,tumor size,TNM stage,operative time,intrao-perative bleeding,postoperative complications,or inflammatory response(P>0.05).Postoperative anal and urinary functions,as assessed by Wexner,low anterior resection syndrome,and International Prostate Symptom Scale scores,were similar in both groups(P>0.05).Long-term follow-up revealed no significant differences in the rates of local recurrence and distant metastasis between the two groups(P>0.05).CONCLUSION R-NOSES I-F is a safe and effective minimally invasive procedure for the treatment of lower rectal cancer.It improves pain relief,promotes gastrointestinal function recovery,and helps avoid incision-related complications. 展开更多
关键词 Robotic surgery Natural orifice specimen extraction surgery Lower rectal cancer Robotic resection using the natural orifice specimen extraction surgery I-type F method
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Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens
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作者 LUO Tingting GUO Yi +4 位作者 DENG Zhao LIU Xiaoqing SUN Zhenya QI Yanyuan YANG Meijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1304-1310,共7页
To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantit... To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides. 展开更多
关键词 analytical transmission electron microscopy(AEM) energy dispersive X-ray spectroscopy(EDS) PYRITE thin specimen quantitative analysis
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Statistical Analysis and Countermeasures for Specimen Rejection in the Emergency Department
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作者 Yinhua Fan Bo Zhao 《Journal of Clinical and Nursing Research》 2023年第4期145-150,共6页
The rejected specimens from the Emergency Department of the Center of Clinical Laboratory from January 1,2022 to January 1,2023 were analyzed to reduce the specimen rejection rates and to improve the quality of inspec... The rejected specimens from the Emergency Department of the Center of Clinical Laboratory from January 1,2022 to January 1,2023 were analyzed to reduce the specimen rejection rates and to improve the quality of inspection.The results showed that there were 1488 samples of rejected specimens and the non-conforming rate was 0.58%.The departments involved were mainly the Emergency Department,the Hematology Department,the Cardiology Department,the Intensive Care Department,and the Brain Surgery Department.Among the reasons for rejection,blood hemolysis accounted for 43.15%,blood coagulation accounted for 26.61%,and the rate of insufficient specimens was 17.14%.Among them,the sample rejection rate for arterial blood gas analysis was the highest,which accounted for 1.74%;followed by specimens for coagulation test,which was 1.18%.These results indicate the main reason for producing rejected specimens is mainly due to not following the standard operating procedure.Specimen rejection can largely be avoided if the standards for specimen collection are strictly followed. 展开更多
关键词 specimen rejection Statistical analysis Quality inspection
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数智化全自动标本转移系统在手术病理标本前处理流程中的应用
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作者 张颖 雷梦君 +4 位作者 玄力娟 孙碧海 司超增 陈静 牛云 《中国护理管理》 CSCD 北大核心 2024年第6期924-928,共5页
目的:探讨在数智化管理背景下,由手术室护士主导的数智化全自动标本转移系统在手术病理标本前处理流程中的应用效果,为提高手术病理标本质量提供参考。方法:构建数智化全自动标本转移系统,并将其应用于手术病理标本前处理流程中,比较系... 目的:探讨在数智化管理背景下,由手术室护士主导的数智化全自动标本转移系统在手术病理标本前处理流程中的应用效果,为提高手术病理标本质量提供参考。方法:构建数智化全自动标本转移系统,并将其应用于手术病理标本前处理流程中,比较系统应用前(2023年4月—7月)和系统应用后(2023年8月—11月)的病理标本送检效率、送检质量、手术室护士心理压力及医护人员满意度。结果:应用数智化全自动标本转移系统后,病理标本前处理流程时长较应用前平均减少3.66 min,一次性接收合格率由87.07%提高至96.42%,病理送检质量满意率较高,护士工作压力显著缓解,医务人员满意度明显提高,以上差异均具有统计学意义(P<0.05)。结论:数智化全自动标本转移系统应用于手术标本前处理流程中可有效提高手术标本前处理效率并缓解护士工作压力,保障病理标本送检质量,为医疗诊断提供可靠的依据,有效减少医务人员职业暴露,提升医护人员满意度。 展开更多
关键词 数智化 全自动标本转移系统 手术病理标本前处理 抽真空处理 冷藏
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寄生虫虫卵悬液永久封制玻片标本制作方法探索
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作者 唐媛媛 王晓楠 +2 位作者 李京培 王林定 李群 《河南大学学报(医学版)》 CAS 2024年第3期184-188,共5页
目的:探索寄生虫虫卵液永久玻片封制标本的最佳制作方法。方法:在现有研究的基础上,改良虫卵悬液保存配方,再结合不同封片方法制作虫卵玻片标本,保存1 a后,再对其制作效果对进行观察。结果:用体积分数为50%的鸡蛋清、40%的福尔马林、10... 目的:探索寄生虫虫卵液永久玻片封制标本的最佳制作方法。方法:在现有研究的基础上,改良虫卵悬液保存配方,再结合不同封片方法制作虫卵玻片标本,保存1 a后,再对其制作效果对进行观察。结果:用体积分数为50%的鸡蛋清、40%的福尔马林、10%的甘油配制的蛋白甘油液保存虫卵,再进行石蜡圈+树胶双封片制作效果最佳。结论:经比较发现虫卵保存液中甘油的含量多少对于虫卵永久封制玻片标本效果的影响很大,其次封制方法对于虫卵液的长期保存也尤为重要。 展开更多
关键词 寄生虫虫卵 蛋白甘油液 标本制作
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甲状腺结节大小对超声引导下细针穿刺活检标本质量影响的研究
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作者 李龙 张苏雅 +2 位作者 吕镔 王贝贝 冷志远 《影像科学与光化学》 CAS 2024年第1期29-33,共5页
本研究旨在评估甲状腺结节大小对超声引导下细针穿刺活检(US-FNAB)标本质量的影响。回顾性分析由同一名超声医生独立完成的614例共733个甲状腺结节US-FNAB患者资料,根据甲状腺结节直径分为A组(<5 mm)、B组(5~10 mm)和C组(>10 mm)... 本研究旨在评估甲状腺结节大小对超声引导下细针穿刺活检(US-FNAB)标本质量的影响。回顾性分析由同一名超声医生独立完成的614例共733个甲状腺结节US-FNAB患者资料,根据甲状腺结节直径分为A组(<5 mm)、B组(5~10 mm)和C组(>10 mm),比较各组间标本不满意率。A组189个结节,不满意率为11.6%(22/189);B组397个结节,不满意率为10.8%(43/397);C组147个结节,不满意率为9.5%(14/147)。三组间US-FNAB标本不满意率比较差异均无统计学意义(P>0.05)。对于一名具有丰富操作经验的医生,甲状腺结节大小不会影响US-FNAB的标本质量。 展开更多
关键词 甲状腺结节 超声检查 活组织检查 细针 标本质量
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2015-2021年CHINET尿液分离菌分布和耐药性变迁
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作者 李艳明 邹明祥 +86 位作者 刘文恩 杨洋 胡付品 朱德妹 徐英春 张小江 张峰波 季萍 谢轶 康梅 王传清 付盼 徐元宏 黄颖 孙自镛 陈中举 倪语星 孙景勇 褚云卓 田素飞 胡志东 李金 俞云松 林洁 单斌 杜艳 郭素芳 魏莲花 邹凤梅 张泓 王春 胡云建 艾效曼 卓超 苏丹虹 郭大文 赵金英 喻华 黄湘宁 金炎 邵春红 徐雪松 鄢超 王山梅 楚亚菲 张利侠 马娟 周树平 周艳 朱镭 孟晋华 董方 吕志勇 胡芳芳 沈瀚 周万青 贾伟 李刚 吴劲松 卢月梅 李继红 段金菊 康建邦 马晓波 郑燕萍 郭如意 朱焱 陈运生 孟青 王世富 胡雪飞 沈继录 汪瑞忠 房华 俞碧霞 赵勇 龚萍 温开镇 张贻荣 刘江山 廖龙凤 顾洪芹 姜琳 贺雯 薛顺虹 冯佼 岳春雷 《中国感染与化疗杂志》 CAS CSCD 北大核心 2024年第3期287-299,共13页
目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共... 目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共分离细菌261893株,其中革兰阳性菌62219株,占23.8%,革兰阴性菌199674株占76.2%。常见的分离菌依次为大肠埃希菌(46.7%)、屎肠球菌(10.4%)、肺炎克雷伯菌(9.8%)、粪肠球菌(8.7%)、奇异变形杆菌(3.5%)、铜绿假单胞菌(3.4%)、无乳链球菌(2.6%)和阴沟肠杆菌(2.1%)。上述细菌主要分离自住院患者,女性多见于男性,成人多见于儿童。大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌中产超广谱β内酰胺酶(ESBL)菌株分别占53.2%、52.8%和37.0%。耐碳青霉烯类的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌中检出率分别为1.7%、18.5%、16.4%和40.3%。粪肠球菌对氨苄西林、呋喃妥因、利奈唑胺、万古霉素、替考拉宁和磷霉素的耐药率<10%,屎肠球菌对氨苄西林、左氧氟沙星、红霉素的耐药率>90%,对万古霉素、利奈唑胺和替考拉宁的耐药率<2%。ICU住院患者分离的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌对大部分抗菌药物的耐药率明显高于门诊患者和非ICU住院患者。结论尿液标本临床分离菌主要以大肠埃希菌、肠球菌和肺炎克雷伯菌为主,不同人群尿液标本中分离的细菌种类和耐药性不尽相同,应重视细菌耐药监测,减少抗菌药物的不合理使用。 展开更多
关键词 尿液 细菌耐药性监测 药物敏感性试验 大肠埃希菌 多重耐药菌
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织物增强混凝土永久模板叠合试件抗氯离子渗透性能研究
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作者 陈欣 王国杰 林颖 《混凝土》 CAS 北大核心 2024年第8期158-162,共5页
织物增强混凝土(TRC)由高性能细骨料混凝土基体与纤维网组成,TRC永久模板与核心混凝土组成叠合试件。为揭示叠合试件氯离子渗透作用规律,确定永久模板最佳厚度范围,以TRC永久厚度、耐碱纤维网层数以及界面处理方式为变量,进行叠合试件... 织物增强混凝土(TRC)由高性能细骨料混凝土基体与纤维网组成,TRC永久模板与核心混凝土组成叠合试件。为揭示叠合试件氯离子渗透作用规律,确定永久模板最佳厚度范围,以TRC永久厚度、耐碱纤维网层数以及界面处理方式为变量,进行叠合试件抗氯离子渗透性能试验研究和计算分析。结果表明:与未设置永久模板相比,当TRC永久模板厚度为10~50 mm时,叠合试件氯离子扩散系数分别降低73.2%~95.6%。耐碱纤维编网对永久模板抗氯离子渗透性能没有增强作用。水泥净浆涂刷、表面凿毛、短切纤维插入三种界面处理方式对叠合试件氯离子渗透系数和渗透深度的影响不显著。结合Duracrete模型定量分析,给出了海洋环境不同工况下TRC永久模板厚度建议范围。 展开更多
关键词 永久模板 叠合试件 氯离子扩散系数 模板厚度
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类岩石试件三轴扰动破坏特性试验研究
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作者 王军 朱传根 +2 位作者 李勋 王波 张艺腾 《采矿与岩层控制工程学报》 EI 北大核心 2024年第2期11-24,共14页
为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试... 为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试件扰动破坏机理。研究结果表明:(1)试件在不同围压下均存在一个阈值强度,轴向荷载超过阈值强度后,轴向变形对扰动变得敏感,再次施加扰动会引起试件显著变形,当轴向荷载低于阈值强度时,变形对扰动不敏感。阈值强度与极限强度的比值可以反映试件的抗扰动能力,随着围压增大,该比值呈现逐步递减的规律,说明高围压下试件抗扰动能力下降,对扰动作用更敏感。(2)扰动作用下类岩石试件存在弱化效应,如常规三轴10MPa围压下试件表现出腰鼓破坏,而受扰动作用后,试件呈现斜切脆性破坏,与常规三轴5MPa围压下破坏形态相近。(3)岩石试件在高应力作用下进入塑性流动状态,内部颗粒重新排列,内部小孔隙与大孔隙的占比减少,而中孔隙的占比显著增多,试件内部孔隙率整体降低。 展开更多
关键词 类岩石试件 三轴扰动 阈值强度 破坏形态 核磁共振
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结直肠癌经自然腔道取标本手术的早期炎性反应、肿瘤学治疗结局与远期预后
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作者 刘远 周晓蕾 +5 位作者 李国雷 李伟 徐志峰 李新宇 徐曌 兴伟 《现代肿瘤医学》 CAS 2024年第13期2380-2386,共7页
目的:比较结直肠癌传统腹腔镜手术(laparoscopic surgery,LAP)与无腹部辅助切口是经自然腔道取标本手术(natural orifice specimen extraction surgery,NOSES)术后的炎性反应程度、肿瘤学治疗结局与远期生存预后。方法:共1 020例患者纳... 目的:比较结直肠癌传统腹腔镜手术(laparoscopic surgery,LAP)与无腹部辅助切口是经自然腔道取标本手术(natural orifice specimen extraction surgery,NOSES)术后的炎性反应程度、肿瘤学治疗结局与远期生存预后。方法:共1 020例患者纳入研究,其中NOSES组416例,LAP组604例。倾向得分匹配平衡两组患者基线资料,最后,两组各有344例患者纳入研究。收集两组患者临床病理特征、围手术期参数、早期炎性反应指标与预后信息。研究终点为5年总生存期(overall survival,OS)、无瘤生存率(disease-free survival,DFS)与无局部复发率生存率(local-recurrence free survival,LRFS)。结果:NOSES具有术后疼痛轻(P<0.05)、额外麻醉药物使用比例少(11.0%vs 29.9%,P<0.001)、切口并发症发生率低(1.5%vs 4.4%,P=0.023)、术后胃肠道功能恢复快(2.7 vs 3.3天,P=0.022)等短期优势。NOSES组患者术后第2天平均体温显著高于LAP组(37.3 vs 37.1℃,P=0.031)。此外,NOSES组患者术后第1、3天的平均中性粒细胞百分比与术后第3天的C反应蛋白水平显著高于LAP组(P<0.05)。然而,两组患者术后盆腔感染并发症发生率无显著差异(0.9%vs 1.2%,P=1.000)。此外,两组患者标本长度、近端切缘距肿瘤距离、远端切缘距肿瘤距离和淋巴结清扫数量等病理结果方面无统计学差异(P>0.05)。预后方面,两组患者有着相似的5年OS(91.6%vs 89.3%,P=0.434)、DFS(84.1%vs 83.6%,P=0.898)与LRFS(95.9%vs 94.0%,P=0.369)。结论:结直肠癌NOSES是安全可行的,有着疼痛轻、恢复快、切口并发症发生率低等明显的短期优势。虽然NOSES手术会在早期引起较强的急性全身炎性反应,然而并不会转化为相关并发症。此外,NOSES手术与LAP有着相似的肿瘤学治疗结局与远期预后,可以在临床工作中广泛开展与推广。 展开更多
关键词 结直肠癌 经自然腔道取标本手术 炎性反应 预后 局部复发
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钢筋混凝土板柱节点冲切性能研究进展 被引量:1
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作者 郑山锁 杜宜阳 +1 位作者 梁泽田 宋枳含 《建筑科学与工程学报》 北大核心 2024年第1期52-68,共17页
为提高板柱节点冲切性能从而促进其工程应用,比较了各类抗冲切元件的不同布置形式、形状尺寸、几何参数以及组合形式对节点抗冲切承载力的影响,概括了受损板柱节点修复与加固的研究现状,梳理了不同开洞尺寸、距离、数量、形状及偏心荷... 为提高板柱节点冲切性能从而促进其工程应用,比较了各类抗冲切元件的不同布置形式、形状尺寸、几何参数以及组合形式对节点抗冲切承载力的影响,概括了受损板柱节点修复与加固的研究现状,梳理了不同开洞尺寸、距离、数量、形状及偏心荷载作用下开洞板柱试件抗冲切性能的研究成果,归纳了有无抗冲切钢筋和配置型钢剪力架板柱节点的抗冲切承载力计算方法以及基于机器学习的板柱节点冲切承载力预测方法。结果表明:各类抗冲切元件可通过改变布置形式、形状尺寸、几何参数以及元件组合从而改善板柱节点的冲切性能;板件开洞的尺寸越大、距离越远、数量越多,对节点的抗冲切性能越不利;基于数值模拟和规范改进得出的冲切承载力计算公式仅对特定试验有较高的预测精度,尚未形成较为统一的承载力计算公式,而基于机器学习的冲切承载力预测模型是未来研究的重点;需进一步开展关于受损板柱节点修复与加固方法的研究,对完善板柱节点抗冲切性能研究理论体系具有重要意义。 展开更多
关键词 板柱节点 抗冲切元件 抗冲切承载力 预测模型 开洞板柱试件 机器学习
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沙土比对混凝土试件空蚀影响的试验研究
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作者 董志勇 徐瀚冉 +1 位作者 李丹 袁雨晨 《浙江工业大学学报》 CAS 北大核心 2024年第4期423-429,共7页
在小型循环式水洞中试验研究了沙土比对混凝土试件空蚀影响的机理。首先,在循环式水洞内筒中配制11种沙土比(0%,10%,20%,30%,40%,50%,60%,70%,80%,90%,100%)试样,用红外测沙仪测定相同沙土比的3种不同含沙量(2,12,30 kg/m 3)的挟沙水样... 在小型循环式水洞中试验研究了沙土比对混凝土试件空蚀影响的机理。首先,在循环式水洞内筒中配制11种沙土比(0%,10%,20%,30%,40%,50%,60%,70%,80%,90%,100%)试样,用红外测沙仪测定相同沙土比的3种不同含沙量(2,12,30 kg/m 3)的挟沙水样,用压力传感器和压力数据采集系统实时采集水洞文丘里工作段空化区和空蚀区的压力;然后,制作了水灰比为0.4、灰砂比为1.5,7 d龄期强度f cu,k=17.8 MPa的混凝土试件,将其安放在水洞文丘里工作段混凝土试件盒中进行4 h的空蚀试验。试验结果表明:沙土比的增大对空化和空蚀破坏均具有促进作用;消失空化数随沙土比的增加而增加,对空化发生具有抑制作用;相同沙土比时,混凝土试件的空蚀量随着含沙量的增加而增加。 展开更多
关键词 沙土比 高速水流 空化空蚀 混凝土试件 消失空化数
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装配整体式梁柱节点的抗震性能对比研究
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作者 刘卫东 许攀熊 +3 位作者 张学伟 霍涛 蒙圣荣 覃智泽 《沈阳建筑大学学报(自然科学版)》 CAS 北大核心 2024年第5期839-847,共9页
目的 研究预制柱纵筋间距放大后装配整体式T型节点和十字型节点的抗震性能,为工程设计提供依据。方法 对5个足尺梁柱节点试件进行低周往复荷载试验,通过对比各试件的滞回曲线、骨架曲线和位移延性等,研究了节点类型、柱纵筋间距和轴压... 目的 研究预制柱纵筋间距放大后装配整体式T型节点和十字型节点的抗震性能,为工程设计提供依据。方法 对5个足尺梁柱节点试件进行低周往复荷载试验,通过对比各试件的滞回曲线、骨架曲线和位移延性等,研究了节点类型、柱纵筋间距和轴压比对梁柱节点抗震性能的影响。结果 装配式节点均发生梁端弯曲破坏,预制柱和节点核心区未见明显破坏,破坏主要是预制梁端底部纵筋屈服和梁端底部混凝土压碎脱落;楼板加强了叠合梁的抗负弯矩能力,叠合梁上部现浇混凝土和预制混凝土交界面出现明显的水平剪切裂缝;柱纵筋间距放大后,与对比试件相比,T型节点的承载力提高了9.2%,十字型节点的承载力提高了1.3%。结论 柱纵筋间距放大试件的延性和耗能能力与对比试件相差不大,柱纵筋间距放大对梁柱节点的抗震性能影响不大;十字型节点和T型节点位移延性系数相差不大。 展开更多
关键词 装配混凝土节点 抗震性能 足尺试件 低周往复荷载试验
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