期刊文献+
共找到11,510篇文章
< 1 2 250 >
每页显示 20 50 100
Efficacy of combined psychological and physical nursing in preventing peripherally inserted central catheter-related thrombosis in gastric cancer patients 被引量:1
1
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
2
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
3
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
Efficacy of single-lumen and double-lumen peripherally inserted central catheters in patients undergoing digestive surgery within bundled care contexts
4
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
Rhodium-catalyzed site-selective cross-couplings of indoles and pyridotriazoles through carbene insertion
5
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
6
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
7
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
Evidence-Based Nursing Optimization for Catheter Tip Positioning in PICC Insertion in Patients with Persistent Left Superior Vena Cava
8
作者 Qian Wang Yaran Zhang +5 位作者 Haiqing Huang Ziwei Xu Xinxin Wang Chenli Zhang Shuqi Wang Bo Xu 《Journal of Clinical and Nursing Research》 2025年第12期21-29,共9页
Objective:To explore the evidence-based nursing optimization strategy for catheter tip positioning during peripherally inserted central catheter(PICC)insertion in patients with persistent left superior vena cava(PLSVC... Objective:To explore the evidence-based nursing optimization strategy for catheter tip positioning during peripherally inserted central catheter(PICC)insertion in patients with persistent left superior vena cava(PLSVC).Methods:For one ovarian cancer patient with PICC malposition in the coronary sinus(CS)due to PLSVC,multimodal imaging techniques were integrated to accurately locate the catheter tip.The catheter position was adjusted based on evidence(withdrawing 5 cm),and a standardized nursing process was established,including personalized health education,catheter fixation and displacement monitoring,complication monitoring,establishment of a specialized disease information archive system,and formulation of a follow-up plan.Results:The catheter tip was successfully withdrawn from the coronary sinus(at the T8 level)to the middle and lower part of the PLSVC(at the T6 vertebral level),and the catheter functioned normally after adjustment.No complications such as arrhythmia or thrombosis occurred during the 332-day chemotherapy period.Conclusion:The PICC tip in PLSVC patients should be positioned in the middle and lower part of the PLSVC(at the T5–T7 vertebral level).This new standard can effectively avoid CS-related complications.The integration of multi-modal imaging techniques and evidence-based nursing management are key to ensuring safe infusion. 展开更多
关键词 Persistent left superior vena cava Peripherally inserted central catheter PICC NURSING
暂未订购
Effect of GaInP and GaAsP inserted into waveguide/barrier interface on carrier leakage in InAlGaAs quantum well 808-nm laser diode
9
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
Lumbar methicillin-resistant Staphylococcus aureus infection caused by a peripherally inserted central catheter:A case report
10
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
Research on the Clinical Application Value of Peripherally Inserted Central Catheter(PICC)after Radical Gastrectomy
11
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
Compound lidocaine cream with warm compress for pain relief in ultrasound-guided peripherally inserted central catheter placement for cancer patients
12
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
Preventive of deep vein thrombosis in cancer patients after peripherally inserted central catheter catheterization using a diversified comprehensive teaching model
13
作者 Xiao-Ying Zhao Yan-Yu Lu +2 位作者 Xian Hong Xiao-Yan Wu Mei-Fang Ruan 《World Journal of Gastrointestinal Surgery》 2025年第11期308-315,共8页
BACKGROUND Peripherally inserted central catheter(PICC)is the preferred intravenous route for chemotherapy in patients with cancer,but its complications,especially deep vein thrombosis(DVT),are becoming increasingly p... BACKGROUND Peripherally inserted central catheter(PICC)is the preferred intravenous route for chemotherapy in patients with cancer,but its complications,especially deep vein thrombosis(DVT),are becoming increasingly prevalent.Medical staff proficient in intubation and maintenance techniques can reduce complications.The multivariate integration teaching model applies the integration of“teaching learning application”to medical training,which helps shift the prevention of complications from“passive management of complications”to“active construction of risk immunity”,thereby ensuring foundational competency for PICC in patients with cancer.AIM To investigate the efficacy of the multivariate integration teaching model in patients with gastric cancer and concurrent DVT after PICC intubation and analyze its effect on patients’quality of life index(QLI)and satisfaction.METHODS A retrospective analysis of medical records of 100 patients with gastric cancer and PICC treated at Zhejiang Provincial People’s Hospital from May 2019 to November 2020 was conducted.According to the different treatment methods and teaching modes received by medical staff,they were divided into a control group and an experimental group,with 50 cases in each group.The routine clinical teaching model and the multivariate integration teaching model were administered to the medical staff for the control group and the experimental group,respectively,to compare the incidence rates of DVT and other adverse reactions,QLI scores,Karnofsky Performance Scale scores,Mental Status Scale in Non-Psychiatric Settings scores,patient satisfaction,medical staff’s test marks,and satisfaction evaluation of the teaching model.RESULTS Compared with the control group,the experimental group exhibited significantly lower incidence rates of DVT and other adverse reactions and MSSNS scores but significantly higher QLI scores,KPS scores,patient satisfaction,medical staff’s test marks,and their satisfaction evaluations of the teaching model(P<0.05).CONCLUSION In a single-center practice,performing the multivariate integration teaching model for medical staff may effectively improve the patients’QLI and satisfaction and may have certain application value in preventing DVT in patients with gastric cancer and PICC. 展开更多
关键词 Multivariate integration teaching model Gastric cancer peripherally inserted central catheter intubation Deep vein thrombosis Quality of life SATISFACTION
暂未订购
Construction and validation of a machine learning algorithm-based predictive model for difficult colonoscopy insertion
14
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
德标减振轨道插入损失率的理论修正方法及应用
15
作者 韦凯 刘延滨 +1 位作者 王显 蒲前华 《西南交通大学学报》 北大核心 2026年第1期117-126,共10页
为准确高效评价轨道减振性能,德国标准DIN V 45673-4规定了插入损失率的高效计算方法,能够排除线路运营条件与轨道不平顺等随机因素的干扰,但该方法在模型等效时未考虑轨道抗弯刚度的贡献,不能准确得到实际轮轨系统共振频率,进而无法准... 为准确高效评价轨道减振性能,德国标准DIN V 45673-4规定了插入损失率的高效计算方法,能够排除线路运营条件与轨道不平顺等随机因素的干扰,但该方法在模型等效时未考虑轨道抗弯刚度的贡献,不能准确得到实际轮轨系统共振频率,进而无法准确判断减振轨道的减振频带.为提高计算精度,在不降低计算效率的前提下改进德标插入损失率计算模型,以弹性地基梁近似反映轨道实际结构尺寸与刚度特征,综合考虑弹性元件与轨道抗弯刚度对轨道刚度的贡献,修正模型刚度;以减振垫浮置板轨道为例,针对我国环评要求的1~80 Hz减振频带,讨论轨道尺寸及弹性元件减振优化方案.研究结果表明:刚度修正后,轮轨系统共振频率误差由76.0%大幅降低至4.9%;单纯提高扣件损耗因子可以实现环评1~80 Hz频带的整体减振,然而在30~90 kN/mm扣件刚度范围内,单纯降低(单纯提高)扣件刚度仅能提高60~80 Hz(30~60 Hz)频带的插入损失率,但是却降低了30~60 Hz(60~80 Hz)的插入损失率,无法实现环评1~80 Hz频带的整体减振;只有当扣件刚度提升至90 kN/mm以上时,才可实现环评1~80 Hz频带的整体减振,且当减振垫刚度越低或浮置板厚度越大时,所需提高的扣件刚度越大. 展开更多
关键词 插入损失率 弹性地基梁 环境振动 刚度修正 扣件参数
在线阅读 下载PDF
Genetic Analysis of a Small Grain Mutant Induced by T-DNA Insertion in Rice 被引量:5
16
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
针刺穴位得气时针感的力学机理分析
17
作者 罗银淼 詹倩 《湖南工业大学学报》 2026年第1期79-84,共6页
通过生物力学分析方法,系统揭示了传统针灸疗法中“得气”现象的力学作用机制,阐明施针者手部力学感知的物理来源及其定量表征。基于针刺过程中组织位移与针体受力显著增强的生物力学实验现象,构建了弹性针体与周围组织的力学耦合系统... 通过生物力学分析方法,系统揭示了传统针灸疗法中“得气”现象的力学作用机制,阐明施针者手部力学感知的物理来源及其定量表征。基于针刺过程中组织位移与针体受力显著增强的生物力学实验现象,构建了弹性针体与周围组织的力学耦合系统。通过建立界面压力-位移动态关系方程,提出基于针尖受力诱导的针体变形位移函数假设,推导施针者手感的力学表征,并采用Langevin团队的生物力学实验数据完成模型验证。研究结果表明:得气效应的力学本质源于针尖刺激引发的周缘组织收缩形变,该过程通过组织-针体耦合作用,导致针体曲率改变及插提阻力增加;施针者的力学感知可量化为组织形变梯度与界面摩擦因数的函数关系。 展开更多
关键词 针刺手法 得气效应 插提阻力 组织界面力学 生物力学建模
在线阅读 下载PDF
我国FCI的构建及其对宏观经济的非对称性冲击 被引量:5
18
作者 肖强 白仲林 《中国经济问题》 CSSCI 北大核心 2015年第5期27-34,共8页
本文针对利率、汇率、股票价格和房地产价格等11个金融变量,利用动态因子模型得到共同金融因子,然后基于VAR模型构建了中国金融状况指数(FCI)。并且以FCI作为转移变量,建立了包含FCI、产出和价格的因子扩展的logistic平滑转移向量自回归... 本文针对利率、汇率、股票价格和房地产价格等11个金融变量,利用动态因子模型得到共同金融因子,然后基于VAR模型构建了中国金融状况指数(FCI)。并且以FCI作为转移变量,建立了包含FCI、产出和价格的因子扩展的logistic平滑转移向量自回归(FALSTVAR)模型,分析FCI对宏观经济变量冲击响应对金融状况变迁的依赖性。实证结果表明,在不同金融状况下,FCI代表的金融市场对产出和价格的影响具有非对称性。在金融状况较好情形下,FCI对产出具有显著的正向冲击效应;而在金融状况恶化的情形下,FCI对产出具有显著负的即有害的影响。 展开更多
关键词 fci 宏观经济 动态因子模型 FALSTVAR
原文传递
金融状况指数FCI与货币政策反应函数经验研究 被引量:49
19
作者 封北麟 王贵民 《财经研究》 CSSCI 北大核心 2006年第12期53-64,共12页
文章运用VAR模型经验估计了中国的金融状况指数FCI,结果表明FCI指数对通货膨胀率具有良好的预测力。在此基础上,将FCI指数作为目标和信息变量纳入泰勒规则,运用GMM方法估计了中国的货币政策反应函数,发现FCI指数与短期利率存在正相关关... 文章运用VAR模型经验估计了中国的金融状况指数FCI,结果表明FCI指数对通货膨胀率具有良好的预测力。在此基础上,将FCI指数作为目标和信息变量纳入泰勒规则,运用GMM方法估计了中国的货币政策反应函数,发现FCI指数与短期利率存在正相关关系,可以成为货币政策的短期指示器;但是利率调节对CPI通胀率、产出缺口和金融形势的松紧变化均反应不足。特别是利率对金融形势松紧变化的调节不足,刺激了金融不平衡和资产价格泡沫的相互推动和累积,是经济不平稳发展的重要政策诱因。 展开更多
关键词 金融状况指数fci 泰勒规则 通货膨胀率
在线阅读 下载PDF
基于可变参数的FCI构建与实证研究 被引量:3
20
作者 许涤龙 欧阳胜银 《统计与信息论坛》 CSSCI 2014年第3期29-35,共7页
通过构建包含利率、汇率、房价、股价、货币供应量和第二产业增加值比重共六个指标的FCI,以具有可变参数特征的状态空间模型为基础,拟合具有可变权重的FCI。实证结果显示:FCI在样本期内的拟合效果基本符合经济现实,用于指示金融松紧程... 通过构建包含利率、汇率、房价、股价、货币供应量和第二产业增加值比重共六个指标的FCI,以具有可变参数特征的状态空间模型为基础,拟合具有可变权重的FCI。实证结果显示:FCI在样本期内的拟合效果基本符合经济现实,用于指示金融松紧程度和经济运行方向的功能明显,2005年第3季度、2008年第3季度和2011年第3季度等时段的金融形势最为紧张,2004年第2季度和2011年第1季度的金融形势最为宽松。 展开更多
关键词 fci 货币政策 可变参数 状态空间模型
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