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Effects of tube cross-sectional shapes on flow pattern, liquid film and heat transfer of n-pentane across tube bundles
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作者 Xuejing He Zhenlin Li +1 位作者 Ji Wang Hai Yu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期16-25,共10页
The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes o... The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes on flow pattern, film thickness and heat transfer of n-pentane across tube bundles, including circle, ellipse-shaped, egg-shaped and cam-shaped tube bundles. Simulation results agree well with experimental data in the literature. The liquid film thickness of sheet flow and heat transfer for different tube shapes were obtained numerically. The flow pattern transition occurs lower vapor quality for ellipse-shaped tube than other tube shapes. For sheet flow, the liquid film on circle tube and ellipseshaped tube is symmetrically distributed along the circumferential direction. However, the liquid film on egg-shaped tube at circumferential angles(θ) = 15°–60° is thicker than θ = 135°–165°. The liquid film on cam tube at θ = 15°–60° is slightly thinner than θ = 135°–165°. The liquid film thickness varies from thinner to thicker for ellipse-shaped, cam-shaped, egg-shape and circle within θ = 15°–60°. The effect of tube shape is insignificant on thin liquid film thickness. Ellipse-shaped tube has largest heat transfer coefficient for sheet flow. In practical engineering, the tube shape could be designed as ellipse to promote heat transfer. 展开更多
关键词 Tube shapes Flow pattern Liquid film thickness Heat transfer Two-phase flow
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Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes 被引量:2
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作者 Hyeonhee Roh Young Jun Yoon +4 位作者 Jin Soo Park Dong-Hyun Kang Seung Min Kwak Byung Chul Lee Maesoon Im 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第2期60-78,共19页
Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to ... Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs.The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)steps.First,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual microneedle.Then,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate.Subsequently,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures.Depending on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the substrate.With these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si wafer.Insertion tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain.To demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding processes.The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on. 展开更多
关键词 MICRONEEDLE Various heights cross-sectional shapes Isotropic etch Deep reactive ion etching
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Optimization of Cross-sectional Shapes of the Bi-2223/Ag Wires before Flat Rolling
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作者 LU Yongjin ZENG Pan +1 位作者 LEI Liping SUN Jianfeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第6期890-895,共6页
Rolling process plays an important role in the manufacture of Bi-based high temperature superconductor tapes, and the plastic flow regularities of the superconducting wires during deformation will directly affect the ... Rolling process plays an important role in the manufacture of Bi-based high temperature superconductor tapes, and the plastic flow regularities of the superconducting wires during deformation will directly affect the ultimate quality of the tapes. In order to investigate the effect of cross-sectional shapes before fiat rolling on the performance and homogeneity of the tapes, some numerical models of Bi-2223/Ag wires with different cross-sectional shapes including circular, square, elliptical and racetrack cross-sections are constructed during the rolling process. By comparing the relative density, logarithmic strain ratio and length-width ratio on the filaments, it is revealed that Bi-2223/Ag wire with special-shaped cross-section can achieve better conductivity than the round wire, in particular, the racetrack cross-sectional wire has the second best performance among four wires. Based on material processability and experimental condition, tri-pass racetrack drawing technique is employed to optimize the process and obtain racetrack cross-sectional wire. The rolling process of Bi-2223/Ag wire with racetrack cross-section causes more intensive deformation of filaments in the center of the tape and achieves the filaments with larger length-width ratio. Also, the deformation distribution of filaments verifies the numerical results. Consequently, the racetrack drawing technique can be utilized for a reference during the mechanical processing and to increase the current transmission capacities of Bi-2223/Ag tapes. 展开更多
关键词 ROLLING cross-sectional shape FILAMENT modelling
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Optimal Cross-Sectional Shape of Gas/Air Ducts
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作者 Yongjian Gu 《World Journal of Engineering and Technology》 2016年第3期250-255,共6页
In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional sha... In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional shapes, such as round or rectangle. The author reveals through geometric calculation of the duct cross-sectional shapes and engineering experiences that the round cross-section is an optimal shape in the duct system. The round duct has the shorter perimeter than the other cross-sectional shape ducts and the stronger structure in the same working condition. The material saving of the round duct due to the shorter perimeter is quantitatively determined. In the pater, it is shown that the round duct is economically attractive. The economic analysis for the material cost saving is illustrated by an example. For a long duct system, the material and material cost savings are significant. It is suggested that the round duct in the gas and air duct system should have priority as long as the field conditions are allowed. In the paper, the material cost saving is also converted to PW, AW, and FW used for LCC economic analysis. 展开更多
关键词 OPTIMAL Ducts cross-sectional shape Economic and Cost Analysis
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Optimization Design of the Multi-Layer Cross-Sectional Layout of An Umbilical Based on the GA-GLM 被引量:1
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作者 YANG Zhi-xun YIN Xu +5 位作者 FAN Zhi-rui YAN Jun LU Yu-cheng SU Qi MAO Yandong WANG Hua-lin 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期247-254,共8页
Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with multi-layers.The layout of these components direct... Marine umbilical is one of the key equipment for subsea oil and gas exploitation,which is usually integrated by a great number of different functional components with multi-layers.The layout of these components directly affects manufacturing,operation and storage performances of the umbilical.For the multi-layer cross-sectional layout design of the umbilical,a quantifiable multi-objective optimization model is established according to the operation and storage requirements.Considering the manufacturing factors,the multi-layering strategy based on contact point identification is introduced for a great number of functional components.Then,the GA-GLM global optimization algorithm is proposed combining the genetic algorithm and the generalized multiplier method,and the selection operator of the genetic algorithm is improved based on the steepest descent method.Genetic algorithm is used to find the optimal solution in the global space,which can converge from any initial layout to the feasible layout solution.The feasible layout solution is taken as the initial value of the generalized multiplier method for fast and accurate solution.Finally,taking umbilicals with a great number of components as examples,the results show that the cross-sectional performance of the umbilical obtained by optimization algorithm is better and the solution efficiency is higher.Meanwhile,the multi-layering strategy is effective and feasible.The design method proposed in this paper can quickly obtain the optimal multi-layer cross-sectional layout,which replaces the manual design,and provides useful reference and guidance for the umbilical industry. 展开更多
关键词 UMBILICAL cross-sectional layout MULTI-LAYERS GA-GLM optimization
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Dyslipidemia in Adults with Type 2 Diabetes in a Rural Community in Ganadougou, Mali: A Cross-Sectional Study
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作者 Abdoulaye Diawara Djibril Mamadou Coulibaly +22 位作者 Drissa Kone Mama A. Traore Drissa Konaté Dicko S. Bazi Oumar Kassogue Djeneba Sylla Fatoumata Gniné Fofana Oudou Diabaté Mariam Traore Ibrahim Antoine Nieantao Kaly Keїta Mamadou Diarra Olivia Smith Jian Li Cheickna Cisse Talib Yusuf Abbas Crystal Zheng Segun Fatumo Kassim Traore Mamadou Wele Mahamadou Diakité Seydou O. Doumbia Jeffrey G. Shaffer 《Journal of Diabetes Mellitus》 CAS 2024年第2期133-152,共20页
Dyslipidemia is a disorder where abnormally lipid concentrations circulate in the bloodstream. The disorder is common in type 2 diabetics (T2D) and is linked with T2D comorbidities, particularly cardiovascular disease... Dyslipidemia is a disorder where abnormally lipid concentrations circulate in the bloodstream. The disorder is common in type 2 diabetics (T2D) and is linked with T2D comorbidities, particularly cardiovascular disease. Dyslipidemia in T2D is typically characterized by elevated plasma triglyceride and low high-density lipoprotein cholesterol (HDL-C) levels. There is a significant gap in the literature regarding dyslipidemia in rural parts of Africa, where lipid profiles may not be captured through routine surveillance. This study aimed to characterize the prevalence and demo-graphic profile of dyslipidemia in T2D in the rural community of Ganadougou, Mali. We performed a cross-sectional study of 104 subjects with T2D in Ganadougou between November 2021 and March 2022. Demographic and lipid profiles were collected through cross-sectional surveys and serological analyses. The overall prevalence of dyslipidemia in T2D patients was 87.5% (91/104), which did not differ by sex (P = .368). High low-density lipoprotein cholesterol (LDL-C) was the most common lipid abnormality (78.9%, [82/104]). Dyslipidemia was associated with age and hypertension status (P = .013 and.036, respectively). High total and high LDL-C parameters were significantly associated with hypertension (P = .029 and .006, respectively). In low-resource settings such as rural Mali, there is a critical need to improve infrastructure for routine dyslipidemia screening to guide its prevention and intervention approaches. The high rates of dyslipidemia observed in Gandadougou, consistent with concomitant increases in cardiovascular diseases in Africa suggest that lipid profile assessments should be incorporated into routine medical care for T2D patients in African rural settings. 展开更多
关键词 CHOLESTEROL cross-sectional Study DYSLIPIDEMIA LIPIDS MALI Type 2 Diabetes
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Association between triglyceride-glucose index and colorectal polyps:A retrospective cross-sectional study
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作者 Ya-Jie Teng Ying-Xue Yang +5 位作者 Jing-Jing Yang Qiu-Yan Lu Jia-Yi Shi Jian-Hao Xu Jie Bao Qing-Hua Wang 《World Journal of Gastrointestinal Endoscopy》 2024年第2期55-63,共9页
BACKGROUND Colorectal polyps(CPs)are frequently occurring abnormal growths in the colorectum,and are a primary precursor of colorectal cancer(CRC).The triglyceride-glucose(TyG)index is a novel marker that assesses met... BACKGROUND Colorectal polyps(CPs)are frequently occurring abnormal growths in the colorectum,and are a primary precursor of colorectal cancer(CRC).The triglyceride-glucose(TyG)index is a novel marker that assesses metabolic health and insulin resistance,and has been linked to gastrointestinal cancers.AIM To investigate the potential association between the TyG index and CPs,as the relation between them has not been documented.METHODS A total of 2537 persons undergoing a routine health physical examination and colonoscopy at The First People's Hospital of Kunshan,Jiangsu Province,China,between January 2020 and December 2022 were included in this retrospective cross-sectional study.After excluding individuals who did not meet the eligibility criteria,descriptive statistics were used to compare characteristics between patients with and without CPs.Logistic regression analyses were conducted to determine the associations between the TyG index and the prevalence of CPs.The TyG index was calculated using the following formula:Ln[triglyceride(mg/dL)×glucose(mg/dL)/2].The presence and types of CPs was determined based on data from colonoscopy reports and pathology reports.RESULTS A nonlinear relation between the TyG index and the prevalence of CPs was identified,and exhibited a curvilinear pattern with a cut-off point of 2.31.A significant association was observed before the turning point,with an odds ratio(95% confidence interval)of 1.70(1.40,2.06),P<0.0001.However,the association between the TyG index and CPs was not significant after the cut-off point,with an odds ratio(95% confidence interval)of 0.57(0.27,1.23),P=0.1521.CONCLUSION Our study revealed a curvilinear association between the TyG index and CPs in Chinese individuals,suggesting its potential utility in developing colonoscopy screening strategies for preventing CRC. 展开更多
关键词 Triglyceride-glucose index Colorectal polyps Colorectal cancer Insulin resistance cross-sectional study
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Mental health and insomnia problems in healthcare workers after the COVID-19 pandemic:A multicenter cross-sectional study
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作者 Wei Ding Min-Zhong Wang +8 位作者 Xian-Wei Zeng Zhen-Hua Liu Yao Meng Hui-Ting Hu Yuan Zhang Yu-Guang Guan Fan-Gang Meng Jian-Guo Zhang Shu Wang 《World Journal of Psychiatry》 SCIE 2024年第5期704-714,共11页
BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and insomnia.These problems can persist for a long period,even afte... BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and insomnia.These problems can persist for a long period,even after the pandemic.However,less is known about this topic.AIM To analyze mental health,insomnia problems,and their influencing factors in HCWs after the COVID-19 pandemic.METHODS This multicenter cross-sectional,hospital-based study was conducted from June 1,2023 to June 30,2023,which was a half-year after the end of the COVID-19 emergency.Region-stratified population-based cluster sampling was applied at the provincial level for Chinese HCWs.Symptoms such as anxiety,depression,and insomnia were evaluated by the Generalized Anxiety Disorder-7,Patient Health Questionnaire-9,and Insomnia Severity Index.Factors influencing the symptoms were identified by multivariable logistic regression.RESULTS A total of 2000 participants were invited,for a response rate of 70.6%.A total of 1412 HCWs[618(43.8%)doctors,583(41.3%)nurses and 211(14.9%)nonfrontline],254(18.0%),231(16.4%),and 289(20.5%)had symptoms of anxiety,depression,and insomnia,respectively;severe symptoms were found in 58(4.1%),49(3.5%),and 111(7.9%)of the participants.Nurses,female sex,and hospitalization for COVID-19 were risk factors for anxiety,depression,and insomnia symptoms;moreover,death from family or friends was a risk factor for insomnia symptoms.During the COVID-19 outbreak,most[1086(76.9%)]of the participating HCWs received psychological interventions,while nearly all[994(70.4%)]of them had received public psychological education.Only 102(7.2%)of the HCWs received individual counseling from COVID-19.CONCLUSION Although the mental health and sleep problems of HCWs were relieved after the COVID-19 pandemic,they still faced challenges and greater risks than did the general population.Identifying risk factors would help in providing targeted interventions.In addition,although a major proportion of HCWs have received public psychological education,individual interventions are still insufficient. 展开更多
关键词 COVID-19 Mental health Psychological symptoms INSOMNIA Sleep disorders cross-sectional study Epidemiological study
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Patterns of Infertility and Abortion in Saudi Arabia: A Cross-Sectional Study
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作者 Majed Saeed Alshahrani 《Open Journal of Obstetrics and Gynecology》 2024年第6期911-922,共12页
Background: Infertility and abortion are significant reproductive health concerns globally, impacting individuals' well-being and healthcare systems. In Saudi Arabia, cultural, social, and religious factors influe... Background: Infertility and abortion are significant reproductive health concerns globally, impacting individuals' well-being and healthcare systems. In Saudi Arabia, cultural, social, and religious factors influence perceptions and management of these issues, necessitating research to understand the patterns and associated factors. Study Aim: This cross-sectional study aimed to investigate the patterns of infertility and abortion among 458 women in Saudi Arabia, focusing on demographic profiles, reproductive histories, medical conditions, and lifestyle factors. Methodology: Participants were recruited from healthcare facilities, and data on age, BMI, reproductive history, medical conditions, assisted reproduction methods, and lifestyle behaviors were collected. Statistical analyses, including chi-square tests, were conducted to examine associations between variables. Results: The majority of participants were aged 30 - 39 years (47.4%), with 76.9% experiencing secondary infertility. Among those with offspring (76.9%), 31% reported using assisted reproduction methods, primarily ovarian stimulators (54.2%). Abortion history was reported by 39.5% of participants. Significant associations were found between age and infertility type (X2 = 5.8, p = 0.054), having offspring and infertility type (X2 = 458.0, p = 0.001), menstrual irregularity and infertility type (X2 = 11.4, p = 0.001), and abortion history and delayed fertility (X2 = 10.4, p = 0.001). Conclusion: Our study reveals significant associations between demographic, medical, and lifestyle factors with infertility patterns and abortion history among Saudi women. These findings emphasize the need for tailored interventions addressing medical conditions, age-related factors, and access to reproductive healthcare services. 展开更多
关键词 INFERTILITY ABORTION Saudi Arabia Reproductive Health Assisted Reproduction cross-sectional Study
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A Cross-Sectional Study on The Prevalence of Anemia in Maintenance Hemodialysis and Peritoneal Dialysis Patients and Its Related Factors
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作者 Mingrong Huang 《Journal of Clinical and Nursing Research》 2024年第3期134-140,共7页
Objective:To study the prevalence of anemia,the proportion of hemoglobin(Hb)levels,the treatment methods,and the influencing factors of Hb levels in maintenance hemodialysis(MHD)and peritoneal dialysis patients.Method... Objective:To study the prevalence of anemia,the proportion of hemoglobin(Hb)levels,the treatment methods,and the influencing factors of Hb levels in maintenance hemodialysis(MHD)and peritoneal dialysis patients.Methods:In this study,602 patients with maintenance hemodialysis and continuous ambulatory peritoneal dialysis were enrolled from December 2020 to December 2022 in our hospital,and their medical records were collected and summarized.The main contents included the patient’s gender,age,primary disease,dialysis duration,dialysis method,the use of erythropoietic stimulating agents(ESA),intravenous iron,and laboratory tests.A Hb index exceeding 110 g/L was set as the standard for the prevalence of anemia.Results:The rate of anemia in patients undergoing blood purification was 83%.The proportion of ESA use was 84.1%,and the proportion of iron use was 76.7%,of which the proportion of intravenous iron used was 17.0%,and the proportion of folic acid used was 28.3%.Conclusion:The incidence of anemia in MHD patients was relatively high,with a low proportion of patients reaching the standard Hb levels.Risk factors include albumin(ALB)levels,iron storage,white blood cells,C-reactive protein,cholesterol,etc.Nutritional support,iron supplementation,and prevention of micro-inflammatory reactions can effectively promote the improvement of Hb indicators in dialysis patients to prevent anemia. 展开更多
关键词 HEMODIALYSIS Peritoneal dialysis ANEMIA Related factors cross-sectional study
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3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因分析
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作者 李娜 《临床医学研究与实践》 2024年第9期85-88,共4页
目的分析并比较3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因,为临床取模以及口内扫描仪性能改善提供参考依据。方法回顾性分析2021年1月至2023年10月实施口腔固定修复治疗并返工的200例患者为研究对象,以取模方式将... 目的分析并比较3shape Trios 3口内扫描和传统硅橡胶在牙体缺损修复中的失败原因,为临床取模以及口内扫描仪性能改善提供参考依据。方法回顾性分析2021年1月至2023年10月实施口腔固定修复治疗并返工的200例患者为研究对象,以取模方式将其分为口扫组(n=97)和硅橡胶组(n=103)。口扫组给予3shape Trios 3口内扫描,硅橡胶组给予传统硅橡胶。比较两组在牙体缺损修复中的失败原因。结果两组的牙体缺损修复失败分布情况比较,差异具有统计学意义(P<0.05);口扫组中,龈下缺损修复失败占比高于龈上(P<0.05)。两组的龈下缺损修复失败原因比较,差异具有统计学意义(P<0.05)。结论相较于传统硅橡胶,3shape Trios 3口内扫描在龈上缺损修复中更有优势,但在龈下缺损修复中,硅橡胶应用效果更佳。 展开更多
关键词 3shape Trios 3口内扫描 硅橡胶 牙体缺损
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Knowledge,attitude,and practice of patients living with inflammatory bowel disease:A cross-sectional study
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作者 Xiao-Xiao Shao Lu-Yan Fang +3 位作者 Xu-Ri Guo Wei-Zhong Wang Rui-Xin Shi Dao-Po Lin 《World Journal of Gastroenterology》 SCIE CAS 2023年第43期5818-5833,共16页
BACKGROUND Patients with inflammatory bowel diseases(IBDs)generally have poor knowledge,attitude,and practice of their disease,while the data from China are lacking.AIM To address this knowledge disparity among Chines... BACKGROUND Patients with inflammatory bowel diseases(IBDs)generally have poor knowledge,attitude,and practice of their disease,while the data from China are lacking.AIM To address this knowledge disparity among Chinese patients with IBD.METHODS This web-based,cross-sectional study was conducted on a cohort of IBD patients who visited the Second Affiliated Hospital of Wenzhou Medical University between December 2022 and February 2023.Their socio-demographic information and the knowledge,attitude,and practice scores were collected and estimated using a self-designed questionnaire.Pearson’s correlation analysis was used to determine the pairwise correlations among knowledge,attitude,and practice scores.A multivariate logistic regression analysis was further performed to determine the independent factors associated with their knowledge,attitude,and practice scores.RESULTS A total of 353 patients(224 males)with IBD completed the questionnaires.The mean knowledge,attitude,and practice scores were 10.05±3.46(possible range:0-14),41.58±5.23(possible range:0-56),44.20±7.39(possible range:0-56),respectively,indicating good knowledge,positive attitude,and proactive practice toward IBD.Pearson’s correlation analysis showed that the knowledge score had significant positive correlations with the attitude score(r=0.371,P<0.001)and practice score(r=0.100,P<0.001).The attitude score had a significant positive correlation with the practice score(r=0.452,P<0.001).Moreover,multivariate logistic regression analysis showed that aged 30-40 years[odds ratio(OR)=4.06,95%confidence interval(CI):1.04-15.82,P=0.043],middle school education(OR=3.98,95%CI:1.29-12.33,P=0.017),high school/technical secondary school education(OR=14.06,95%CI:3.92-50.38,P<0.001),and junior college/bachelor’s degree and above education(OR=15.20,95%CI:4.15-55.650,P<0.001)were independently associated with good knowledge.The higher knowledge score was independently associated with a positive attitude(OR=1.23,95%CI:1.11-1.36,P<0.001).The higher attitude score was independently associated with proactive practice(OR=1.20,95%CI:1.11-1.30,P<0.001).CONCLUSION Chinese patients with IBD might have good knowledge,a positive attitude,and proactive practice toward their disease.However,a small number of specific items require education. 展开更多
关键词 ATTITUDE cross-sectional study Inflammatory bowel disease KNOWLEDGE PRACTICE QUESTIONNAIRE
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Exercise, Depression, and Anxiety in Young People: A Cross-Sectional Survey
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作者 Meilin Huo Zhen Yang 《International Journal of Mental Health Promotion》 2023年第4期551-562,共12页
Background:Depression and anxiety are highly prevalent among adolescents and have multiple negative effects on their physical and mental health.While exercise can reduce the symptoms of depression and anxiety,the rela... Background:Depression and anxiety are highly prevalent among adolescents and have multiple negative effects on their physical and mental health.While exercise can reduce the symptoms of depression and anxiety,the rela-tionship between mental disorders among American university students has been rarely reported.Accordingly,this study aimed to explore the association between exercise,depression and anxiety among American university students in the 2018–2019 academic year.Methods:In this cross-sectional study,the association between exercise,depression and anxiety was investigated in a large representative sample of American university students.In the 2018–2019 academic year,university students aged 18+years old from 79 institutions participated in this school-based study.The questionnaire included measurements of demographic characteristics,exercise,and validated screen instructions for depression(PHQ-9)and anxiety(GAD-7).The multivariable logistic regression model was applied to explore the association between exercise,depression and anxiety.Results:A total of 62026 indivi-duals(31.9%males)participated in this survey,and the prevalence of exercising at least 5 h each day was 24.6%.The prevalence of depression and anxiety was 25.7%and 22.3%,respectively.In the multivariable logistic regres-sion model,compared to exercise at least 5 h daily,participants whose exercise less than 1 h daily(OR=1.31[1.29,1.33],p<0.05),2 to 3 h daily(OR=1.13[1.11,1.15],p<0.05),3 to 4 h daily(OR=1.04[1.02,1.06],p<0.05),were correlated with greater odds of depression,while exercise less than 1 h daily(OR=1.23[1.21,1.25],p<0.05),2 to 3 h daily(OR=1.10[1.08,1.12],p<0.05)were significantly correlated with great-er odds of anxiety.Conclusion:Higher levels of exercise are associated with lower risk of depression and anxiety among American university students.Community and school interventions should focus on increasing exercise participation in university populations to promote both physical and mental health. 展开更多
关键词 EXERCISE DEPRESSION ANXIETY ADOLESCENT cross-sectional studies
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Machine learning-assisted efficient design of Cu-based shape memory alloy with specific phase transition temperature 被引量:1
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作者 Mengwei Wu Wei Yong +2 位作者 Cunqin Fu Chunmei Ma Ruiping Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期773-785,共13页
The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important prac... The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important practical significance.In this work,machine learning(ML)methods were utilized to accelerate the search for shape memory alloys with targeted properties(phase transition temperature).A group of component data was selected to design shape memory alloys using reverse design method from numerous unexplored data.Component modeling and feature modeling were used to predict the phase transition temperature of the shape memory alloys.The experimental results of the shape memory alloys were obtained to verify the effectiveness of the support vector regression(SVR)model.The results show that the machine learning model can obtain target materials more efficiently and pertinently,and realize the accurate and rapid design of shape memory alloys with specific target phase transition temperature.On this basis,the relationship between phase transition temperature and material descriptors is analyzed,and it is proved that the key factors affecting the phase transition temperature of shape memory alloys are based on the strength of the bond energy between atoms.This work provides new ideas for the controllable design and performance optimization of Cu-based shape memory alloys. 展开更多
关键词 machine learning support vector regression shape memory alloys martensitic transformation temperature
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Endoscopy demand among county people in southeast China:A cross-sectional study
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作者 Huihui Yan Zhenghua Lin +12 位作者 Shuangjing Gao Chenyu Fan Mengyue Jiang Liying Que Lanfang Zhou Yingdi Weng Jing Shu Tongyun Zhang Jian Hu Zhiqiang Liu Xi Ye Jianting Cai Guangfa Liao 《Laparoscopic, Endoscopic and Robotic Surgery》 2023年第1期9-15,共7页
Objective The popularization of gastroenteroscopy and the introduction of comfortable medical care have further promoted the growth of people's demand,especially the demand for painless endoscopy.This cross-sectio... Objective The popularization of gastroenteroscopy and the introduction of comfortable medical care have further promoted the growth of people's demand,especially the demand for painless endoscopy.This cross-sectional study aims to investigate the current situation and change in county people's demand for endoscopy to promote the development of endoscopy centers in county hospitals in southeast China.Methods From October to December 2021,patients and their family members who came to the Gastroenterology Department in Suichang County People's Hospital of Zhejiang Province were randomly selected to complete the questionnaire.A total of 838 valid questionnaires were collected.Additionally,the original software data of the Endoscopy Center were sampled and retrieved(from October to December every year from 2018 to 2021)for statistical analysis of real-world data.Those who would choose painless endoscopy the next time in the valid questionnaires were included in the painless endoscopy group,while those who would choose ordinary endoscopy the next time were included in the ordinary endoscopy group.Results The stepwise forward binary logistic regression model analysis showed that,patients with“secondhand smoke exposure”were more willing to choose painless endoscopy(OR=1.459,95%CI:1.050-2.028,p=0.025).However,patients with an education level of“primary and below”and“junior high school”,and patients who are suffering from“currently experiencing abdominal distension”,were more willing to choose ordinary endoscopy(OR=0.270,95%CI:0.149-0.488,p<0.001;OR=0.528,95%CI:0.330-0.845,p=0.008;OR=0.536,95%CI:0.334-0.861,p=0.010).Patients with previous experience in painless endoscopy tended to choose painless endoscopy the next time,while patients with previous experience in ordinary endoscopy tended to choose ordinary endoscopy the next time(χ^(2)=140.97,p<0.001).From 2018 to 2021,the proportion of painless endoscopy has increased yearly(p<0.001).Most patients indicated that they would“regularly review gastroenteroscopy”(477/838,56.9%).Conclusions With Suichang County of Zhejiang Province as the representative,the demand for painless endoscopy for people's gastrointestinal cancer detection in southeast China has been increasing yearly.The development of endoscopy centers in county-level hospitals can basically meet the demand growth.Meanwhile,advanced concepts such as comfortable medical care and regular follow-up are gradually popularized at the grassroots level in southeast China. 展开更多
关键词 County people Comfortable medical care Painless endoscopy Endoscopic demand cross-sectional study
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Determinants of internet addiction among medical students in Casablanca: a cross-sectional study
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作者 Boubacar Traore Yassine Aguilo +1 位作者 Samira Hassoune Samira Nani 《Global Health Journal》 2023年第2期101-109,共9页
Objective:This study aimed to estimate the prevalence and determinants of Internet addiction among medical students at the Faculty of Medicine and Pharmacy of Casablanca,Morocco.Methods:This was a cross-sectional stud... Objective:This study aimed to estimate the prevalence and determinants of Internet addiction among medical students at the Faculty of Medicine and Pharmacy of Casablanca,Morocco.Methods:This was a cross-sectional study conducted among students at the Faculty of Medicine and Pharmacy in Casablanca between October and March 2020.An online questionnaire was administered to students to collect data and internet addiction was assessed by the Young questionnaire.A score threshold≥50 was adopted to define addiction.Univariate and multivariate logistic regression analyses were used to identify factors associated with internet addiction.Results:Out of a total of 4093 FMPC students enrolled in the 2020-2021 academic year,506 agreed to participate in this study,including 303 females and 203 males.The mean addiction score assessed on the Young scale was(49.08±16.11).The prevalence of Internet addiction was 44.5%(225/506,95% CI:40% to 49%).Multiple regression analysis showed that being older than 20 years(OR=0.17,95% CI:0.40 to 0.64),being female(OR=1.70,95% CI:1.04 to 2.78),being in the dissertation year(6th year)(OR=5.17,95% CI:2.23 to 11.44),having a history of psychiatric consultation(OR=2.64,95% CI:1.34 to 5.21),having divorced parents(OR=2.64,95% CI:1.05 to 5.87),use of sleeping medication(OR=2.9,95% CI:1.05 to 3.70),sleep disorders(OR=2.06,95% CI:1.25 to 3.79),sleep deprivation(OR=2.26,95% CI:1.39 to 3.65),excessive daytime sleepiness(OR=5.39,95% CI:2.19 to 13.24),anxiety disorders(OR=1.47,95% CI:1.18 to 2.30),duration of internet connection(>4 h)(OR=11.43,95% CI:4.85 to 27.66),and having frequent conflicts with parents(OR=2.37,95% CI:1.49 to 3.79)and friends(OR=0.26,95% CI:0.11 to 0.65)were independently associated with internet addiction.Conclusion:The prevalence of Internet addiction among medical students in Casablanca remains high.Targeted action on the determinants would be of great value in prevention. 展开更多
关键词 Internet addiction disorder Medical students Associated factors cross-sectional study Morocco
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The L-shaped association between superoxide dismutase levels and blood pressure in older Chinese adults:community-based,cross-sectional study 被引量:1
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作者 Ying HUANG Wei LAI +3 位作者 Hong CHEN Qi-Fan LIU Ju-Xiang LI Jin-Zhu HU 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2022年第1期71-82,共12页
BACKGROUND As an antioxidant,serum superoxide dismutase(SOD)have been found to be associated with hypertension.METHODS The data were derived from the Chinese Longitudinal Healthy Longevity Survey(CLHLS),a prospective ... BACKGROUND As an antioxidant,serum superoxide dismutase(SOD)have been found to be associated with hypertension.METHODS The data were derived from the Chinese Longitudinal Healthy Longevity Survey(CLHLS),a prospective cohort study in China.We explored the association between serum SOD and blood pressure(BP)using multivariable correction analysis in an older Chinese population.RESULTS We observed a significantly gradual downward trend in the association between serum SOD levels and diastolic BP(DBP)in participants with lower serum SOD levels(<58 IU/mL),while no associations were observed between serum SOD levels and DBP in participants with higher serum SOD levels(>58 IU/mL).Similar results showed a significant gradual downward trend in associations between serum SOD levels and the risk of diastolic hypertension only at SOD<58 IU/mL.Multiple linear regression analysis suggested that serum SOD was negatively correlated with DBP(Sβ=-0.088,P<0.001)but not with SBP(Sβ=0.013,P=0.607).Multiple logistic regression analysis suggested that serum SOD was independently associated with the risk of diastolic hypertension(OR=0.984,95%CI:0.973−0.996,P=0.010)but not with the risk of systolic hypertension(OR=1.001,95%CI:0.990−1.012,P=0.836))after adjusting for relevant confounding factors.Serum SOD levels(<58 IU/mL,>58 IU/mL)were an effect modifier of the association between serum SOD and DBP(interaction P=0.0038)or the risk of diastolic hypertension(interaction P=0.0050).CONCLUSIONS Our study indicated for the first time that there was an L-shaped association between serum SOD levels and the risk of diastolic hypertension in the older Chinese population. 展开更多
关键词 HYPERTENSION shaped Serum
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Lung Function Impairment among Gasoline Attendants: A Cross-Sectional Study
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作者 Emmanuel Obazee Henry Aiwuyo +8 位作者 Anthony Kweki Tinuade Obazee Tinuade Obazee John Osarenkhoe Uche Agboje Beatrice Torere Nosakhare Ilerhunmwuwa Uchenna Amaechi Gabriel Alugba 《Open Journal of Ecology》 2023年第3期48-63,共16页
Background: Occupational health is an important consideration, especially for people that work in an environment with pollutants. Gasoline attendants are individuals that work in filling stations. They are constantly ... Background: Occupational health is an important consideration, especially for people that work in an environment with pollutants. Gasoline attendants are individuals that work in filling stations. They are constantly exposed to gasoline fumes and automobile engine products from vehicle exhaust. This increases the risk of acute and chronic respiratory diseases and carcinogenesis among them. The risk of health complications tends to increase with the duration of exposure. The study aimed to determine the proportion of gasoline attendants with lung function impairment. Methods and Materials: Two hundred and eight eligible participants were recruited for this study. A cross-sectional analytical study was carried out in Esan West local government area of Edo state, Nigeria. The study was carried out for a period of six months from December 2015 to May 2016. A questionnaire was used to obtain information on demographic characteristics, work history, mode of exposure and duration of exposure to petrol fumes. Lung function was assessed using a DTspiro spirometer (Model POP 10. Serial no 110843-005);also the anthropometric parameters of the respondent were measured. Statistical analysis was done using IBM SPSS version 20.0. Frequency and percentages were used to present categorical data. The mean and standard deviation of continuous variables were calculated and compared using the student’s t-test. The criteria of significant association were assumed for a p-value less than 0.05. Results: A total of one hundred and forty petrol pump attendants and one hundred and forty controls participated in this study. The mean age for petrol pump attendants was 24 ± 3.1 years and 23 ± 2.8 years for the control group. There were no significant differences in the gender distribution and anthropometric parameters as observed in this study. The lung impairment pattern observed in this study was obstructive in twelve (8.6%) gasoline pump attendants and restrictive pattern in thirty-nine (27.9%) gasoline pump attendants, while only four (2.9%) had an obstructive pattern and twelve (8.6%) had a restrictive pattern of lung impairment among the control group. This implies that a restrictive pattern was predominant. This study also observed that there was an increase in the number of gasoline pump attendants with declined lung function compared to the control group. Conclusion: Restrictive pattern of lung impairment was more predominant than the obstructive pattern among gasoline pump attendants. As a result, public health interventions should be instituted among these individuals, especially in developing countries. 展开更多
关键词 Lung Function Test Lung Impairment Lung Impairment Pattern Gasoline Attendants Occupational Hazards cross-sectional Study
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The Frequency of the v-AKT Murine Thymoma Viral Oncogene Homologue 1 Gene Amplification among Sudanese Women with Ovarian Cancer: A Cross-Sectional Study
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作者 Rawia Eljaili Elmassry Aisha Osman Mohammed +7 位作者 Amina Ibrahim Badawy Rasha Saad Abdalhamid Huda Abdalla Eltahir Safa Abass Mohammed Hammad Yahia Abdou Adil Abdelrahim Yousif Zubaida Abohumeda Adam Nazik Elmalaika Husaim 《Open Journal of Genetics》 2023年第2期75-82,共8页
Background: Protein kinase B (AKT/PKB) family is frequently amplified in ovarian cancer (OC). To the greatest of our knowledge, there is a lack of published reports about the amplification of the genes belonging to th... Background: Protein kinase B (AKT/PKB) family is frequently amplified in ovarian cancer (OC). To the greatest of our knowledge, there is a lack of published reports about the amplification of the genes belonging to the AKT family among Sudanese women with OC. The present study was conducted to detect the AKT1 gene amplification and its association with tumour types, grades, and ages among Sudanese women with OC, bearing in mind the ethnic variation. Methods: This institution-based study included 79 cases of women diagnosed with ovarian cancer (OC) at Omdurman Maternity Hospital in the period 2013-2018. Formalin-fixed, paraffin-embedded (FFPE) tissue sections were used to extract RNA. AKT1 gene amplification was assessed using quantitative real-time PCR. Results: The mean age (±SD) of included women was 49.29 (±13.612). The amplification of AKT1 gene was observed in 18/79 (22.8%) of OC women, with a high frequency in women with undifferentiated 1/2 (50%), clear cell 2/6 (33.3%), mucinous 3/11 (27.3%), endometrioid 3/17 (17.6%), and serous carcinomas 5/30 OC (16.7%). High frequency was seen in women with low (26.3%;n = 10/28) rather than in higher (19.5%;n = 8/33) grade carcinoma, and in older (25.8%;n = 8/23) rather than younger (18.2%;n = 2/9) women. No significant association between AKT1 gene amplification and tumour types, grades, and ages of women was observed (Fisher’s Exact test: p = 0.405, 0.593 and 0.851, respectively). Conclusion: AKT1 gene amplification arises in around one-fifth of Sudanese women with ovarian cancer (OC). It is seen more in undifferentiated, clear cell, and mucinous tumours types, and more frequently in low tumour grade and older women, but not to a statistically significant level. These outcomes sustenance previous studies suggesting that activated AKT genes have a vital role in OC progression and may offer a plan for targeted therapy and prognostic evaluation. 展开更多
关键词 AKT1 Gene Amplification Ovarian Cancer cross-sectional Study Quantitative Real-Time PCR Sudan
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基于改进Alpha Shape算法的点云数据岛屿边界提取
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作者 宋晓辉 熊祖雄 +2 位作者 张炎 吕富强 韦建林 《海洋测绘》 CSCD 北大核心 2024年第1期58-62,共5页
针对机载LiDAR点云的岛屿岸线提取过程复杂、附属岛屿岸线难以提取等问题,提出一种基于改进Alpha Shape算法的点云数据岛屿边界提取方法。首先利用布料模拟滤波算法剔除非岛屿点云数据,通过欧式聚类进行不同岛屿的提取,再将岛屿点云数... 针对机载LiDAR点云的岛屿岸线提取过程复杂、附属岛屿岸线难以提取等问题,提出一种基于改进Alpha Shape算法的点云数据岛屿边界提取方法。首先利用布料模拟滤波算法剔除非岛屿点云数据,通过欧式聚类进行不同岛屿的提取,再将岛屿点云数据投影至二维平面,并根据岛屿点云构建格网。在此基础上使用自适应Alpha Shape算法,对提取出的岛屿点云进行边界提取,即可得到岛屿的岸线轮廓。选取新西兰的玛提尤/萨姆斯岛作为研究区域,并将本文算法与Alpha Shape算法进行对比,结果表明:本文算法提取岛屿边界点云的精准度为97.78%,可以准确地提取岛屿岸线,为海岛规划提供参考。 展开更多
关键词 摄影测量 机载LiDAR点云 边界提取 欧式聚类 自适应Alpha shape
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