期刊文献+
共找到11,187篇文章
< 1 2 250 >
每页显示 20 50 100
Efficacy of single-lumen and double-lumen peripherally inserted central catheters in patients undergoing digestive surgery within bundled care contexts
1
作者 Xiao-Hui Ye Rong-Hong Cui +3 位作者 Lei Xu Mei-Jun Wang Ling-Rong Ye Ming Jiang 《World Journal of Gastrointestinal Surgery》 2025年第9期215-226,共12页
BACKGROUND Peripherally inserted central catheters(PICCs)are crucial for patients requiring long-term intravenous therapy,especially within digestive surgery under bundled care protocols.AIM To evaluate and compare th... BACKGROUND Peripherally inserted central catheters(PICCs)are crucial for patients requiring long-term intravenous therapy,especially within digestive surgery under bundled care protocols.AIM To evaluate and compare the efficacy,safety,and patient-reported outcomes of single-lumen vs double-lumen PICCs among patients undergoing digestive surgery within a structured bundled care framework.METHODS This retrospective cohort study analyzed data from 249 patients who underwent digestive surgery and utilized either single-lumen(n=117)or double-lumen(n=132)PICCs between January 2021 and June 2024.Clinical outcomes,patient satisfaction,catheterization duration,and complication rates were compared using statistical analysis via SPSS(version 29.0).The bundled care protocol was consistently applied,focusing on standardized procedures,staff training,and patient support.RESULTS Single-lumen PICCs were associated with a significantly lower thrombosis rate(0.85%)than double-lumen PICCs(6.82%,P=0.039).The single-lumen group experienced shorter catheterization durations(12.5±3.14 days vs 13.6±4.50 days,P=0.025)and higher successful infusion rates(92.7%±5.32%vs 90.4%±6.60%,P=0.003).This group also reported higher comfort scores(8.40±1.20 vs 7.90±1.50,P=0.004)and lower pain levels(2.90±0.70 vs 3.20±0.80,P=0.002).Aside from thrombosis,complication rates showed no significant difference between the groups.CONCLUSION Within bundled care context,single-lumen PICCs demonstrated advantages in reducing thrombosis risk,procedural efficiency,patient comfort,and satisfaction compared with double-lumen PICCs.The findings underscore the importance of considering patient-specific needs and clinical scenarios in catheter choice. 展开更多
关键词 Single-lumen peripherally inserted central catheter Double-lumen peripherally inserted central catheter Digestive surgery Bundled care Patient satisfaction THROMBOSIS
暂未订购
Efficacy of combined psychological and physical nursing in preventing peripherally inserted central catheter-related thrombosis in gastric cancer patients 被引量:1
2
作者 Wei-Jing Ni Yu-Xiu Xi Yong-Chao Zhou 《World Journal of Gastrointestinal Surgery》 2025年第3期206-212,共7页
BACKGROUND Long-term chemotherapy for patients with gastric cancer(GC),facilitated by peripherally inserted central catheter(PICC)catheterization,reduces vascular damage and enhances drug delivery efficiency but carri... BACKGROUND Long-term chemotherapy for patients with gastric cancer(GC),facilitated by peripherally inserted central catheter(PICC)catheterization,reduces vascular damage and enhances drug delivery efficiency but carries risks of catheter-related complications.A combination of group psychological nursing and physical mo-vement care significantly mitigates the risk of venous thrombosis and improves psychological well-being,and enhances motor function,underscoring its clinical importance.AIM To assess group psychological and physical movement nursing in preventing venous thrombosis in patients with PICC GC.METHODS Sixty-five GC patients with PICC,admitted from January 2022 to January 2023,were randomly divided into two groups using the lottery method:A control group(n=35,routine nursing)and an observation group(n=30,routine nursing plus psychological nursing and physical movement nursing).Both groups re-ceived continuous care for 2 weeks.Pre-nursing and post-nursing data on psycho-logical state,physical function,chemotherapy-related thrombosis incidence,and cancer-related fatigue were analyzed using SPSS 26.0 and GraphPad Prism 8.0.RESULTS After nursing,both groups showed reduced Hamilton Anxiety Scale scores and increased General Perceived Self-Efficacy Scale scores,with the observation group performing better(P<0.05).The Functional Comprehensive Assessment score for the observation group after nursing was(65.42±2.35)points,lower than the control group’s(62.19±4.33)points(P<0.05).Although no significant difference was observed in the incidence of venous thrombosis between the two groups(χ2=0.815,P=0.367),the observation group had lower incidence.Both groups showed decreased Revised Piper Fatigue Scale scores,with the observation group scoring lower(P<0.05).CONCLUSION Group psychological and physical movement nursing for patients with PICC reduces venous thrombosis risk,improves psychological well-being,cancer-related fatigue,and physical function,making it highly promotable. 展开更多
关键词 Group psychological nursing Physical movement nursing Peripherally inserted central catheter Gastric cancer Venous thrombosis Cancer-related fatigue
暂未订购
TfOH-Catalyzed O-H Insertion of Carboxylic Acids with α-Aryl Diazoesters
3
作者 Chen Guifang Li Hongqiang Zeng Xingrong 《有机化学》 北大核心 2025年第7期2537-2544,共8页
An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acylox... An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acyloxy esters in moderate to high yields with a broad substrate scope.All starting materials are readily available,and the reactions can be conducted in the open air at room temperature. 展开更多
关键词 carboxylic acids α-aryl diazoesters TfOH O-H insertion
原文传递
Blue Light-Induced Formal Insertion Reaction ofα-Siloxy Carbene into C-H Bond of 1,3-Diketones
4
作者 Jiang Xinyu Zhang Xinke +1 位作者 Fang Xi Xu Xinfang 《有机化学》 北大核心 2025年第6期2231-2238,共8页
A blue light-induced formal insertion reaction ofα-siloxy carbene into the C—H bond of 1,3-diketones has been reported.Under the irradiation of blue light,acylsilane converts toα-siloxy carbene,which then undergoes... A blue light-induced formal insertion reaction ofα-siloxy carbene into the C—H bond of 1,3-diketones has been reported.Under the irradiation of blue light,acylsilane converts toα-siloxy carbene,which then undergoes formal C—H bond insertion reaction with the enol form of 1,3-diketone.This method uses readily available and relative stable acylsilane as car-bene precursor,which features a simple and metal-free approach under mild conditions.Moreover,the synthetic potential of this protocol has been demonstrated by performing the reaction on a gram scale with comparable high yield. 展开更多
关键词 photoinduction α-siloxy carbene 1 3-diketone C-H bond insertion reaction
原文传递
Effect of GaInP and GaAsP inserted into waveguide/barrier interface on carrier leakage in InAlGaAs quantum well 808-nm laser diode
5
作者 FU Meng-jie DONG Hai-liang +3 位作者 JIA Zhi-gang JIA Wei LIANG Jian XU Bing-she 《中国光学(中英文)》 北大核心 2025年第1期186-197,共12页
There is nonradiative recombination in waveguide region owing to severe carrier leakage,which in turn reduces output power and wall-plug efficiency.In this paper,we designed a novel epitaxial structure,which suppresse... There is nonradiative recombination in waveguide region owing to severe carrier leakage,which in turn reduces output power and wall-plug efficiency.In this paper,we designed a novel epitaxial structure,which suppresses carrier leakage by inserting n-Ga_(0.55)In_(0.45)P and p-GaAs_(0.6)P_(0.4) between barriers and waveguide layers,respectively,to modulate the energy band structure and to increase the height of barrier.The results show that the leakage current density reduces by 87.71%,compared to traditional structure.The nonradiative recombination current density of novel structure reduces to 37.411 A/cm^(2),and the output power reaches 12.80 W with wall-plug efficiency of 78.24%at an injection current density 5 A/cm^(2) at room temperature.In addition,the temperature drift coefficient of center wavelength is 0.206 nm/℃at the temperature range from 5℃to 65℃,and the slope of fitted straight line of threshold current with temperature variation is 0.00113.The novel epitaxial structure provides a theoretical basis for achieving high-power laser diode. 展开更多
关键词 808-nm laser diode Ga_(0.55)In_(0.45)P and GaAs_(0.6)P_(0.4)insertion layers InAlGaAs quantum well carrier leakage
在线阅读 下载PDF
Rhodium-catalyzed site-selective cross-couplings of indoles and pyridotriazoles through carbene insertion
6
作者 Hua Tian Xin Yang +2 位作者 Ge Shi Heng Xu Yi Dong 《Chinese Chemical Letters》 2025年第7期302-307,共6页
The switchable cross-coupling of indoles and pyridotriazoles through carbene insertion at C_(2)-or C_(3)-positon has been developed in this paper.This highly site-selective C-H carbenoid functionalization is determine... The switchable cross-coupling of indoles and pyridotriazoles through carbene insertion at C_(2)-or C_(3)-positon has been developed in this paper.This highly site-selective C-H carbenoid functionalization is determined by both the Rh-catalyst species and auxiliary groups.[Cp∗RhCl_(2)]_(2) and coordinating pyrimidyl group direct the C-H carbenoid functionalization to occur at the C_(2)-position,while Rh2OAc4 and noncoordinating benzyl group lead the reaction to occur at the C_(3)-position of the indoles.This regioselective C−H functionalization strategy is of significant importance for the discovery of indole drugs. 展开更多
关键词 RHODIUM-CATALYZED Site-selective CROSS-COUPLINGS Carbene insertion Pyridotriazoles
原文传递
Personalizing withdrawal time by insertion time to achieve target adenoma detection rate in colonoscopy
7
作者 Bing-Xin Xu Cong-Zhou Xu +3 位作者 Hao-Yan Zhang Xu-Jin Chen Bing-Ni Wei Cheng Yang 《World Journal of Gastroenterology》 2025年第38期105-119,共15页
BACKGROUND Adenoma detection rate(ADR),a key colonoscopy quality metric,varies with patient demographics and procedural factors.AIM To identify independent predictors of≥25%ADR,develop a risk model,and propose withdr... BACKGROUND Adenoma detection rate(ADR),a key colonoscopy quality metric,varies with patient demographics and procedural factors.AIM To identify independent predictors of≥25%ADR,develop a risk model,and propose withdrawal durations based on different insertion times.METHODS We retrospectively analyzed 830 cases using logistic regression and identified four key factors,validated in a prospective cohort of 5699 patients.Their importance was confirmed using random forest(RF),extreme gradient boosting(XGBoost)and light gradient boosting machine(LightGBM).Attempts to determine targetachieving withdrawal time by grouping cases based on insertion time and Cox regression were inconclusive.Using the 5699-case dataset,we developed a predictive model combining support vector machine(SVM)with XGBoost.We built a Shiny app using this model for clinical application.RESULTS Multivariate logistic regression identified age[odds ratio(OR)=1.05;95%confidence interval(CI):1.03-1.08;P<0.001],male(OR=1.79;95%CI:1.32-2.41;P=0.005),higher endoscopist experience(OR=1.79;95%CI:1.20-2.68;P=0.005),and longer withdrawal time(P<0.001)as independent risk factors for colorectal adenoma.A nomogram demonstrated strong discrimination[area under the curve(AUC)=0.720],with robust calibration and decision-curve performance.Feature importance via RF,XGBoost,and LightGBM confirmed key predictors.A hybrid model combining SVM regression for withdrawal-time estimation and XGBoost classification achieved stable results,with XGBoost reporting AUCs of 0.640 in training and 0.610 in testing,and similar validation outcomes.Deployed via a Shiny app for clinical use.However,model discrimination was modest(AUC:0.61-0.64),suggesting that clinical utility requires further refinement.CONCLUSION A hybrid SVM-XGBoost model using four key endoscopic factors was independently validated and is available as a Shiny app,delivering real-time decision support to streamline endoscopy and enhance clinical outcomes. 展开更多
关键词 COLONOSCOPY Withdrawal time insertion time Adenoma detection rate Machine learning
暂未订购
Concise synthesis of NDP-activated uronic acid by an oxidation reaction insertion strategy
8
作者 Nana Yang Rui Yuan +5 位作者 Xinyue Fu Xiao Tian Jin Yu Shengzhou Ma Liuqing Wen Jiabin Zhang 《Chinese Chemical Letters》 2025年第8期296-302,共7页
Uronic acids are prevalent components of crucial glycoconjugates,pivotal in various biological processes.In nature,NDP-uronic acids,the nucleosides-activated uronic acids,serve as glycosylation donors catalyzed by uro... Uronic acids are prevalent components of crucial glycoconjugates,pivotal in various biological processes.In nature,NDP-uronic acids,the nucleosides-activated uronic acids,serve as glycosylation donors catalyzed by uronosyltransferases(UATs)to construct glycans containing uronic acids.Despite their biological importance,the synthesis of naturally occurring NDP-uronic acids on a large scale remains challenging.Here,we developed an oxidation reaction insertion strategy for the efficient synthesis of NDP-uronic acids,and 11 NDP-uronic acids were successfully prepared in good yield and on a large scale.The prepared NDP-uronic acids can be used to explore new uronosyltransferases and synthesize uronic acids containing carbohydrates for fundamental research. 展开更多
关键词 NDP-uronic acids BIOCATALYSIS Enzyme-mediated biomimetic synthesis Oxidation reaction insertion strategy
原文传递
Lumbar methicillin-resistant Staphylococcus aureus infection caused by a peripherally inserted central catheter:A case report
9
作者 Xiao-Xiao Yuan Qiong-Qiong Tan +2 位作者 Chen Chen Qing-Qing He Yan-Ning Li 《World Journal of Clinical Cases》 2025年第19期84-91,共8页
BACKGROUND Peripherally inserted central catheters(PICCs)are widely used for administering chemotherapy to breast cancer patients due to their long-term indwelling capability,versatility in drug administration,and fle... BACKGROUND Peripherally inserted central catheters(PICCs)are widely used for administering chemotherapy to breast cancer patients due to their long-term indwelling capability,versatility in drug administration,and flexibility.PICCs infection are a relatively common occurrence,yet there were no reported instances that it can metastasise to the lumbar spine.CASE SUMMARY This case report describes a breast cancer patient who developed a methicillinresistant Staphylococcus aureus lumbar vertebral infection secondary to a PICCrelated infection during chemotherapy.Following PICC removal,bacterial culture confirmed the presence of highly virulent methicillin-resistant Staphylococcus aureus.The patient presented with fever and severe lumbar pain.Lumbar magnetic resonance imaging revealed paraspinal muscle edema from L1 to L3 with abnormal signal intensity in the affected regions,suggestive of vertebral osteomyelitis.Prompt initiation of appropriate antibiotic therapy based on the culture results led to significant improvement in the patient’s lumbar pain.CONCLUSION This case highlights the importance of vigilant infection prevention and control measures to minimize the risk of PICC-related complications,such as bloodstream infections and subsequent metastatic infections. 展开更多
关键词 Peripherally inserted central catheter Methicillin-resistant Staphylococcus aureus infection Lumbar magnetic resonance imaging Breast cancer CHEMOTHERAPY Case report
暂未订购
Compound lidocaine cream with warm compress for pain relief in ultrasound-guided peripherally inserted central catheter placement for cancer patients
10
作者 Yan Wang Xue-Ni Yang +4 位作者 Sheng Ji Yu-Mei Zhang Yi Wang Yan-Mei Wang Yue-Xia Gu 《World Journal of Clinical Oncology》 2025年第7期217-223,共7页
BACKGROUND Ultrasound-guided peripherally inserted central catheter(PICC)placement is vital for cancer therapy,but lidocaine infiltration faces limitations like puncture pain and vasospasm.AIM To assess the clinical e... BACKGROUND Ultrasound-guided peripherally inserted central catheter(PICC)placement is vital for cancer therapy,but lidocaine infiltration faces limitations like puncture pain and vasospasm.AIM To assess the clinical efficacy of a no-pain intervention-combining compound lidocaine cream with warm compress-in reducing pain during ultrasound-guided PICC placement in cancer patients.METHODS A retrospective cohort study analyzed 88 cancer patients undergoing PICC placement(Shanghai Fourth People’s Hospital,2024).Patients were divided into control(lidocaine infiltration,n=44)and intervention(cream+warm compress,n=44)groups.Primary outcomes:Pain scores(numerical rating scale),procedural time,complications;secondary outcome:Satisfaction.RESULTS The intervention group showed significantly lower pain scores(1.2±0.4 vs 3.8±1.2,P=0.012)with comparable first-attempt success(95.5%vs 90.9%)and safety(P=0.672).Thermal activation of transient receptor potential vanilloid 1 channel enhanced drug penetration,achieving anesthesia within 8-10 minutes.Patient satisfaction reached 97.7%.CONCLUSION The combination of compound lidocaine cream with warm compress significantly alleviates procedural pain and enhances patient satisfaction during ultrasound-guided PICC placement in cancer patients,supporting its clinical application. 展开更多
关键词 ULTRASOUND-GUIDED Peripherally inserted central catheter placement Pain relief Compound lidocaine cream Warm compress Retrospective study Cancer patients
暂未订购
Construction and validation of a machine learning algorithm-based predictive model for difficult colonoscopy insertion
11
作者 Ren-Xuan Gao Xin-Lei Wang +6 位作者 Ming-Jie Tian Xiao-Ming Li Jia-Jia Zhang Jun-Jing Wang Jing Gao Chao Zhang Zhi-Ting Li 《World Journal of Gastrointestinal Endoscopy》 2025年第7期149-161,共13页
BACKGROUND Difficulty of colonoscopy insertion(DCI)significantly affects colonoscopy effectiveness and serves as a key quality indicator.Predicting and evaluating DCI risk preoperatively is crucial for optimizing intr... BACKGROUND Difficulty of colonoscopy insertion(DCI)significantly affects colonoscopy effectiveness and serves as a key quality indicator.Predicting and evaluating DCI risk preoperatively is crucial for optimizing intraoperative strategies.AIM To evaluate the predictive performance of machine learning(ML)algorithms for DCI by comparing three modeling approaches,identify factors influencing DCI,and develop a preoperative prediction model using ML algorithms to enhance colonoscopy quality and efficiency.METHODS This cross-sectional study enrolled 712 patients who underwent colonoscopy at a tertiary hospital between June 2020 and May 2021.Demographic data,past medical history,medication use,and psychological status were collected.The endoscopist assessed DCI using the visual analogue scale.After univariate screening,predictive models were developed using multivariable logistic regression,least absolute shrinkage and selection operator(LASSO)regression,and random forest(RF)algorithms.Model performance was evaluated based on discrimination,calibration,and decision curve analysis(DCA),and results were visualized using nomograms.RESULTS A total of 712 patients(53.8%male;mean age 54.5 years±12.9 years)were included.Logistic regression analysis identified constipation[odds ratio(OR)=2.254,95%confidence interval(CI):1.289-3.931],abdominal circumference(AC)(77.5–91.9 cm,OR=1.895,95%CI:1.065-3.350;AC≥92 cm,OR=1.271,95%CI:0.730-2.188),and anxiety(OR=1.071,95%CI:1.044-1.100)as predictive factors for DCI,validated by LASSO and RF methods.Model performance revealed training/validation sensitivities of 0.826/0.925,0.924/0.868,and 1.000/0.981;specificities of 0.602/0.511,0.510/0.562,and 0.977/0.526;and corresponding area under the receiver operating characteristic curves(AUCs)of 0.780(0.737-0.823)/0.726(0.654-0.799),0.754(0.710-0.798)/0.723(0.656-0.791),and 1.000(1.000-1.000)/0.754(0.688-0.820),respectively.DCA indicated optimal net benefit within probability thresholds of 0-0.9 and 0.05-0.37.The RF model demonstrated superior diagnostic accuracy,reflected by perfect training sensitivity(1.000)and highest validation AUC(0.754),outperforming other methods in clinical applicability.CONCLUSION The RF-based model exhibited superior predictive accuracy for DCI compared to multivariable logistic and LASSO regression models.This approach supports individualized preoperative optimization,enhancing colonoscopy quality through targeted risk stratification. 展开更多
关键词 COLONOSCOPY Difficulty of colonoscopy insertion Machine learning algorithms Predictive model Logistic regression Least absolute shrinkage and selection operator regression Random forest
暂未订购
Research on the Clinical Application Value of Peripherally Inserted Central Catheter(PICC)after Radical Gastrectomy
12
作者 Xing Su Haixia Zhao Yuchen Huang 《Journal of Clinical and Nursing Research》 2025年第8期305-311,共7页
Objective:Patients after radical gastrectomy often require medium-to long-term intravenous therapy.However,traditional central venous catheters(CVCs)have issues such as high infection risk and poor comfort.This study ... Objective:Patients after radical gastrectomy often require medium-to long-term intravenous therapy.However,traditional central venous catheters(CVCs)have issues such as high infection risk and poor comfort.This study aims to deeply explore the clinical application value of peripherally inserted central catheters(PICCs)after radical gastrectomy,providing a scientific basis for optimizing intravenous access selection.Methods:Fifty patients requiring catheterization after radical gastrectomy at the Friendship Hospital of Ili Kazak Autonomous Prefecture from December 2022 to May 2024 were selected.Catheterization site selection was based on patients’preferences,dividing them into two groups:the experimental group receiving PICCs and the control group receiving CVCs,with 25 patients in each group.Multi-dimensional comparative analysis was conducted,including catheterization operation time,catheter indwelling time,success rates of first and second catheterizations,and complication rates.Statistical methods such as t-tests and chi-square tests were used for in-depth analysis.Results:Compared to the control group,the experimental group had longer catheterization operations and catheter indwelling times,and a higher success rate of first catheterization(P<0.05).The incidence of catheterization complications in the experimental group was 12.00%,lower than the 40.00%in the control group(P<0.05).Conclusion:Although PICC catheterization after radical gastrectomy has relatively longer catheterization operation and indwelling times,it has a high success rate of first catheterization and a low complication rate,demonstrating high clinical application value and worth promoting in clinical practice. 展开更多
关键词 Peripherally inserted central catheter(PICC) Central venous catheter(CVC) Post-radical gastrectomy
暂未订购
Genetic Analysis of a Small Grain Mutant Induced by T-DNA Insertion in Rice 被引量:5
13
作者 张向前 朱海涛 +1 位作者 邹金松 曾瑞珍 《Agricultural Science & Technology》 CAS 2008年第3期63-66,91,共5页
[Objective] The aim of this study is to understand the genetic characteristics of a grain shape mutant and its possible role in genetic improvement of grain yield in rice. [Method] On the basis of the collection of T-... [Objective] The aim of this study is to understand the genetic characteristics of a grain shape mutant and its possible role in genetic improvement of grain yield in rice. [Method] On the basis of the collection of T-DNA tag lines, the progeny of homozygous plants carrying T-DNA insertion were screened for mutants with mutated phenotypes. The genetic analysis of the mutant and test for the linkage between the mutated phenotype and the T-DNA insertion were carried out to determine its genetic characteristics. [Result] In the present study, a grain shape mutant induced by T-DNA insertion in rice was identified, which showed small grain. Genetic analysis of the mutant showed that the two types of phenotype, normal and small grain in the segregating populations derived from the T-DNA heterozygotes, fit the ratio of 3∶1. Test for Basta resistance showed that all the mutants were resistant while the normal plants segregated for resistant and susceptible by the ratio of 2∶1. The results indicated that the mutant phenotype cosegregated with Bar gene. The small grain mutant caused by T-DNA insertion was confirmed by PCR amplification aiming at T-DNA. [Conclusion] The grain shape mutant is useful for isolation of the tagged gene and genetic improvement in rice. 展开更多
关键词 ORYZA SATIVA GRAIN shape MUTANT T-DNA insertion
在线阅读 下载PDF
高分辨率小动物Micro Insert PET系统的模拟研究 被引量:1
14
作者 尹永智 李梅春 +2 位作者 王慧鹏 姚丽萍 叶征乾 《核技术》 CAS CSCD 北大核心 2014年第11期23-28,共6页
在西门子Micro PET小动物成像系统中接入高分辨率的Insert探测器环,组成了Micro Insert PET系统,可以进一步提高小动物PET系统的图像分辨率。本文采用蒙特卡罗模拟软件GATE定义Focus-220小动物PET和Micro Insert两种系统,在同步仿真运算... 在西门子Micro PET小动物成像系统中接入高分辨率的Insert探测器环,组成了Micro Insert PET系统,可以进一步提高小动物PET系统的图像分辨率。本文采用蒙特卡罗模拟软件GATE定义Focus-220小动物PET和Micro Insert两种系统,在同步仿真运算中,给出了三种类型的符合数据,即PET Scanner和PET Scanner之间的符合、PET Scanner和Insert之间的符合、Insert和Insert之间的符合。用滤波反投影算法重建了Na-22单点源模型、多点源模型、LZU模型的PET图像。其中,多点源模型的径向图像分辨率的仿真结果与美国华盛顿大学的Micro Insert实验数据,在忽略正电子射程、非线性效应项以及噪声等的贡献下,两者符合得很好。研究表明,使用Micro Insert系统能够将小动物PET系统的图像分辨率提高到亚毫米水平。 展开更多
关键词 蒙特卡罗仿真 小动物PET MICRO insert系统 图像重建
原文传递
Preparation of BCEC-Astrocyte Co-culturing Membrane Plate Insert 被引量:1
15
作者 赵康峰 王琪 +2 位作者 蒲小平 杨秀伟 朱玉真 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第4期276-281,共6页
To prepare a hand-made micropore membrane culture plate insert forco-culture. Methods The plate insert was made using plastic centrifuge tube and micropore membrane.After seeding brain capillary endothelial cells (BCE... To prepare a hand-made micropore membrane culture plate insert forco-culture. Methods The plate insert was made using plastic centrifuge tube and micropore membrane.After seeding brain capillary endothelial cells (BCECs) on it (under the effect ofastrocyte-conditioned medium), the plate insert was assessed by analysis of trans-endothelialelectrical resistance (TEER). Results The plate insert has a stability of at least 15 d underculture condition. TEER increased significantly under co-culture condition from (66.1 +- 13.3)Ωcm^2 to (182.2 +- 6.7) Ωcm^2. Conclusion This micropore membrane culture plate insert can beeasily made, on which BCEC culture can be successfully performed. Moreover, it is adjustable andrecyclable. It follows that the plate insert is a useful tool for co-culture and the relatedresearch fields. 展开更多
关键词 blood-brain barrier culture plate insert brain capillary endothelial cell ASTROCYTE trans-endothelial electronic resistance
暂未订购
Needle Steering for Robot-Assisted Insertion into Soft Tissue:A Survey 被引量:7
16
作者 GAO Dedong LEI Yong ZHENG Haojun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第4期629-638,共10页
Needle insertion is a common surgical procedure used in diagnosis and treatment.The needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on ne... Needle insertion is a common surgical procedure used in diagnosis and treatment.The needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on needle insertion.It is necessary to summarize and analyze the existing results to promote the future development of theories and applications of needle insertion.Thus,a survey of the state of the art of research is presented on algorithms of needle steering techniques,the surgical robots and devices.Based on the analysis of the needle insertion procedure,the concept of needle steering is defined as a kinematics problem,which is to place the needle at the target and avoid the obstacles.The needle steering techniques,including the artificial potential field method and the nonholonomic model,are introduced to control the needles for improving the accuracy.Based on the quasi-static thinking,the virtual spring model and the cantilever-beam model are developed to calculate the amount of needle deflection and generate the needle path.The phantoms instead of the real tissue are used to verify the models mentioned in most of the experimentations.For the desired needle trajectories,the image-guided robotic devices and some novel needles are presented to achieve the needle steering.Finally,the challenges are provided involving the controllability of the long flexible needle and the properties of soft tissue.The results and investigations can be used for further study on the precision and accuracy of needle insertion. 展开更多
关键词 needle insertion needle steering robot-assisted needle insertion path planning needle deflection tissue deformation
在线阅读 下载PDF
Counter-ion insertion of chloride in Mn3O4 as cathode for dual-ion batteries: A new mechanism of electrosynthesis for reversible anion storage 被引量:3
17
作者 Heng Jiang Xiulei Ji 《Carbon Energy》 CAS 2020年第3期437-442,共6页
Irreversible reductive insertion of Zn2+transforms Mn3O4 such that the resulting Zn0.2Mn3O4 exhibits highly reversible storage properties of chloride ions,thus rendering Zn0.2Mn3O4 an excellent cathode of aqueous dual... Irreversible reductive insertion of Zn2+transforms Mn3O4 such that the resulting Zn0.2Mn3O4 exhibits highly reversible storage properties of chloride ions,thus rendering Zn0.2Mn3O4 an excellent cathode of aqueous dual-ion batteries.With Zn2+trapped,Zn0.2Mn3O4 delivers the chloride-storage capacity over 200 mAh/g at an average potential of 1.6 V vs Zn2+/Zn by reversibly forming a new ionic compound equivalent to Zn0.2Mn3O4Cl1.7.Electrochemical quartz crystal microbalance results suggest chloride as the primary charge carrier in the reversible oxidative anion insertion.The Mn3O4 anion-hosting cathode couples with Zn metal anode in a full-cell dual-ion battery,demonstrating stable cycling in practical pouch cells with an energy density of 150 Wh/kg based on the mass of both electrodes. 展开更多
关键词 anion insertion counter-ion insertion dual-ion battery metal oxide cathode Zn batteries
在线阅读 下载PDF
Timing Optimization by Inserting Minimum Buffers with Accurate Delay Models
18
作者 张轶谦 洪先龙 +1 位作者 周强 蔡懿慈 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第11期1409-1415,共7页
An algorithm of minimizing the number of buffers under certain delay constraint with accurate delay models is presented.Given a two-terminal net,the algorithm can minimize the total number of buffers inserted to meet ... An algorithm of minimizing the number of buffers under certain delay constraint with accurate delay models is presented.Given a two-terminal net,the algorithm can minimize the total number of buffers inserted to meet the delay constraint.A high order delay model is applied to estimate interconnect delay and a nonlinear delay model based on look-up table is for buffer delay estimation.The experimental results show that the algorithm can efficiently achieve the trade-offs between number of buffers and delay,and avoid needless power and area cost.The running time is satisfactory. 展开更多
关键词 buffer insertion interconnect optimization layout VLSI
在线阅读 下载PDF
Lack of association between ADRA2B-4825 gene insertion/deletion poly- morphism and migraine in Chinese Han population
19
作者 倪健强 贾莎莎 +4 位作者 刘民 陈守恭 姜玉婷 董万利 高玉振 《Neuroscience Bulletin》 SCIE CAS CSCD 2010年第4期322-326,共5页
Objective The present study aimed to estimate the association between susceptibility to migraine and the 12nucleotide insertion/deletion (indel) polymorphism in promoter region ofα 2B -adrenergic receptor gene (AD... Objective The present study aimed to estimate the association between susceptibility to migraine and the 12nucleotide insertion/deletion (indel) polymorphism in promoter region ofα 2B -adrenergic receptor gene (ADRA2B).Methods A case-control study was carried out in Chinese Han population,including 368 cases of migraine and 517 controls.Genomic DNA was extracted from blood samples,and DNA fragments containing the site of polymorphism were amplified by PCR.Data were adjusted for sex,age,migraine history and family history,and analyzed using a logistic regression model.Results There was no association between indel polymorphism and migraine,at either the allele or the genotype level.Conclusion These findings do not support a functional significance of ADRA2B indel polymorphism at position-4825 relative to the start codon in the far upstream region of the promoter in the present migraine subjects. 展开更多
关键词 MIGRAINE promoter ofα 2B -adrenergic receptor gene insertion/deletion polymorphism genetic association
原文传递
Path-Based Timing Optimization by Buffer Insertion with Accurate Delay Model
20
作者 张轶谦 周强 +1 位作者 洪先龙 蔡懿慈 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第5期520-525,共6页
An algorithm of path based timing optimization by buffer insertion is presented.The algorithm adopts a high order model to estimate interconnect delay and a nonlinear delay model based on look up table for gate dela... An algorithm of path based timing optimization by buffer insertion is presented.The algorithm adopts a high order model to estimate interconnect delay and a nonlinear delay model based on look up table for gate delay estimation.And heuristic method of buffer insertion is presented to reduce delay.The algorithm is tested by industral circuit case.Experimental results show that the algorithm can optimize the timing of circuit efficiently and the timing constraint is satisfied. 展开更多
关键词 buffer insertion timing optimization interconnect planning routing algorithm
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部