Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning eve...Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning events due to rip currents in recent years.To address this issue,a comprehensive study was conducted based on developing a depth-averaged 2D hydrodynamic model to simulate rip currents in the Bai Dai-Cam Ranh coast.The HYDIST-2D numerical model was applied to simulate the rip current evolution in space and time for the study area.The results showed that the HYDIST-2D numerical model can accurately predict the location,magnitude,and microstructure of rip currents,including rip current speed,width,and length.The simulation results revealed that the rip current speed is greater during the low tide phase,with an average speed of 0.5 m s^(-1),while during high tide,the rip current speed is lower,around 0.1–0.8 m s^(-1).The width and length of the rip current also vary with the tide phase,with a wider and longer rip current observed during the low tide phase.The results also showed that the rip current speed and microstructure are influenced by the wave features,tide current,and bathymetry of the study area.The present study provides valuable insights into the dynamics of rip currents in the Bai Dai-Cam Ranh coast.The findings can be used to support the management of bathing activities and provide early warnings for potential risks associated with rip currents.展开更多
Background:Subcortical ischemic vascular dementia(SIVD)is a common subtype of vascular dementia.Currently,the bilateral common carotid artery stenosis(BCAS)mouse model is the most suitable SIVD rodent model.In this st...Background:Subcortical ischemic vascular dementia(SIVD)is a common subtype of vascular dementia.Currently,the bilateral common carotid artery stenosis(BCAS)mouse model is the most suitable SIVD rodent model.In this study,we investigated the functional and structural impairments in the hippocampus 1 month after BCAS.Methods:We used behavioral tests,laser speckle flowmetry,long-term potentiation,histochemical staining,molecular experiments,and voxel-based morphometry to evaluate the hippocampal impairments.Results:Behavioral studies revealed that BCAS mice exhibited worse performance.Laser speckle flowmetry detected an obvious decrease in cerebral blood flow.The synaptic plasticity of the perforant path-dentate gyrus pathway was inhibited.Decreased fractional anisotropy and increased mean diffusivity were detected in the hippocampus via diffusion tensor imaging data.A reduction in gray matter volume,which was most prominent in the hippocampus and its surrounding areas,was de-tected via voxel-based morphometry analysis.Impairments in cell morphology and myelin integrity were validated using histochemical staining and molecular biology techniques.In addition,the numbers of GFAP+astrocytes and Iba1+microglia in-creased in the hippocampus.Conclusions:Overall,our study demonstrates early functional and structural impair-ments in the hippocampus contributing to learning and memory deficits after 1 month of BCAS,indicating that the hippocampus is vulnerable to chronic cerebral ischemia.展开更多
针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造...针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。展开更多
An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the inc...An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the increase of the elastic stiffness,the change of the yield surface due to MICP cementation and the degradation of calcium carbonate bonds during shearing.Specifically,to capture the typical contraction-dilation transition in MICP soils,the original volumetric hardening rule in the MCC model is modified to a combined deviatoric and volumetric hardening rule.The model could reproduce a series of drained triaxial tests on MICP-treated soils with different calcium carbonate contents.Further,we carry out a parametric study and observe numerical instability in some cases.In combination with an analytical analysis,our numerical modelling has identified the benefits and limitations of using MCCbased models in the simulation of MICP-cemented soils,leading to suggestions for further model development.展开更多
Context/Objective: High blood pressure (HBP) currently represents the most widespread chronic non-communicable disease in Cameroon. The increase in its prevalence in the country is the result of multiple factors inclu...Context/Objective: High blood pressure (HBP) currently represents the most widespread chronic non-communicable disease in Cameroon. The increase in its prevalence in the country is the result of multiple factors including economic stress imposed by precariousness, poor living conditions, sources of anxiety, anguish, depression and other behavioral disorders. Economic stress is a globalizing concept that integrates into a purely hermeneutic approach, a particular functioning of the nervous system of an individual who faces employment problems and precarious remuneration conditions. The non-satisfaction by an individual of his basic needs due to insufficient financial means can cause him to become irritable, aggressive, and socially and symbolically isolated, thereby increasing the desire to resort to morbid life models such as excessive consumption of narcotics and other psychoactive substances often associated with high blood pressure. The fight against the emergence of BPH is a complex, multifaceted and multifactorial reality that requires taking into account economic stress. The main objective of this survey is to describe the situation of economic stress within the Cameroonian population, which imposes precariousness and life models at risk of high blood pressure. Specifically, we determined the level of household income and the sources of income. Methods: A cross-sectional survey with a descriptive aim among five hundred households in the Central Region of Cameroon was conducted. A probabilistic technique called simple randomness was used. The number of households to be surveyed was determined indirectly using the Cochrane formula. Data collection in face-to-face mode using a physical questionnaire took place from July 1 to August 31, 2023, after obtaining ethical clearance from the Regional Health Research Ethics Committee, Human from the Center and an administrative authorization for data collection. Regarding their processing, the data was grouped during processing in Excel sheets. Normality and reliability tests of the collected data were carried out. For this, the Chi-square test was used for data with a qualitative value and that of Kolmogorov-Sminorf for data with a quantitative value. Descriptive analysis was possible using R software version 3.2, SPSS version 25.0, XLSTAT 2016, PAST and EXCEL programs from Microsoft Office 2013. Results: The main results highlight economic stress, with 45.60% of households surveyed earning less than US$154 per month;55% of household heads were women in single-parent families;14% of household heads were unemployed, 22% worked in the private sector and 19% were self-employed. This general economic situation leads to precarious living conditions, thereby increasing the risk of high blood pressure among the Cameroonian population.展开更多
BACKGROUND Rebleeding after recovery from esophagogastric variceal bleeding(EGVB)is a severe complication that is associated with high rates of both incidence and mortality.Despite its clinical importance,recognized p...BACKGROUND Rebleeding after recovery from esophagogastric variceal bleeding(EGVB)is a severe complication that is associated with high rates of both incidence and mortality.Despite its clinical importance,recognized prognostic models that can effectively predict esophagogastric variceal rebleeding in patients with liver cirrhosis are lacking.AIM To construct and externally validate a reliable prognostic model for predicting the occurrence of esophagogastric variceal rebleeding.METHODS This study included 477 EGVB patients across 2 cohorts:The derivation cohort(n=322)and the validation cohort(n=155).The primary outcome was rebleeding events within 1 year.The least absolute shrinkage and selection operator was applied for predictor selection,and multivariate Cox regression analysis was used to construct the prognostic model.Internal validation was performed with bootstrap resampling.We assessed the discrimination,calibration and accuracy of the model,and performed patient risk stratification.RESULTS Six predictors,including albumin and aspartate aminotransferase concentrations,white blood cell count,and the presence of ascites,portal vein thrombosis,and bleeding signs,were selected for the rebleeding event prediction following endoscopic treatment(REPET)model.In predicting rebleeding within 1 year,the REPET model ex-hibited a concordance index of 0.775 and a Brier score of 0.143 in the derivation cohort,alongside 0.862 and 0.127 in the validation cohort.Furthermore,the REPET model revealed a significant difference in rebleeding rates(P<0.01)between low-risk patients and intermediate-to high-risk patients in both cohorts.CONCLUSION We constructed and validated a new prognostic model for variceal rebleeding with excellent predictive per-formance,which will improve the clinical management of rebleeding in EGVB patients.展开更多
文摘Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning events due to rip currents in recent years.To address this issue,a comprehensive study was conducted based on developing a depth-averaged 2D hydrodynamic model to simulate rip currents in the Bai Dai-Cam Ranh coast.The HYDIST-2D numerical model was applied to simulate the rip current evolution in space and time for the study area.The results showed that the HYDIST-2D numerical model can accurately predict the location,magnitude,and microstructure of rip currents,including rip current speed,width,and length.The simulation results revealed that the rip current speed is greater during the low tide phase,with an average speed of 0.5 m s^(-1),while during high tide,the rip current speed is lower,around 0.1–0.8 m s^(-1).The width and length of the rip current also vary with the tide phase,with a wider and longer rip current observed during the low tide phase.The results also showed that the rip current speed and microstructure are influenced by the wave features,tide current,and bathymetry of the study area.The present study provides valuable insights into the dynamics of rip currents in the Bai Dai-Cam Ranh coast.The findings can be used to support the management of bathing activities and provide early warnings for potential risks associated with rip currents.
基金supported by Tianjin Key Medical Discipline(Specialty)Construction Project(grant number TJYXZDXK-004A).
文摘Background:Subcortical ischemic vascular dementia(SIVD)is a common subtype of vascular dementia.Currently,the bilateral common carotid artery stenosis(BCAS)mouse model is the most suitable SIVD rodent model.In this study,we investigated the functional and structural impairments in the hippocampus 1 month after BCAS.Methods:We used behavioral tests,laser speckle flowmetry,long-term potentiation,histochemical staining,molecular experiments,and voxel-based morphometry to evaluate the hippocampal impairments.Results:Behavioral studies revealed that BCAS mice exhibited worse performance.Laser speckle flowmetry detected an obvious decrease in cerebral blood flow.The synaptic plasticity of the perforant path-dentate gyrus pathway was inhibited.Decreased fractional anisotropy and increased mean diffusivity were detected in the hippocampus via diffusion tensor imaging data.A reduction in gray matter volume,which was most prominent in the hippocampus and its surrounding areas,was de-tected via voxel-based morphometry analysis.Impairments in cell morphology and myelin integrity were validated using histochemical staining and molecular biology techniques.In addition,the numbers of GFAP+astrocytes and Iba1+microglia in-creased in the hippocampus.Conclusions:Overall,our study demonstrates early functional and structural impair-ments in the hippocampus contributing to learning and memory deficits after 1 month of BCAS,indicating that the hippocampus is vulnerable to chronic cerebral ischemia.
文摘针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。
基金funded by the German Research Foundation(DFG)(Grant No.NA 330/20e1).
文摘An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the increase of the elastic stiffness,the change of the yield surface due to MICP cementation and the degradation of calcium carbonate bonds during shearing.Specifically,to capture the typical contraction-dilation transition in MICP soils,the original volumetric hardening rule in the MCC model is modified to a combined deviatoric and volumetric hardening rule.The model could reproduce a series of drained triaxial tests on MICP-treated soils with different calcium carbonate contents.Further,we carry out a parametric study and observe numerical instability in some cases.In combination with an analytical analysis,our numerical modelling has identified the benefits and limitations of using MCCbased models in the simulation of MICP-cemented soils,leading to suggestions for further model development.
文摘Context/Objective: High blood pressure (HBP) currently represents the most widespread chronic non-communicable disease in Cameroon. The increase in its prevalence in the country is the result of multiple factors including economic stress imposed by precariousness, poor living conditions, sources of anxiety, anguish, depression and other behavioral disorders. Economic stress is a globalizing concept that integrates into a purely hermeneutic approach, a particular functioning of the nervous system of an individual who faces employment problems and precarious remuneration conditions. The non-satisfaction by an individual of his basic needs due to insufficient financial means can cause him to become irritable, aggressive, and socially and symbolically isolated, thereby increasing the desire to resort to morbid life models such as excessive consumption of narcotics and other psychoactive substances often associated with high blood pressure. The fight against the emergence of BPH is a complex, multifaceted and multifactorial reality that requires taking into account economic stress. The main objective of this survey is to describe the situation of economic stress within the Cameroonian population, which imposes precariousness and life models at risk of high blood pressure. Specifically, we determined the level of household income and the sources of income. Methods: A cross-sectional survey with a descriptive aim among five hundred households in the Central Region of Cameroon was conducted. A probabilistic technique called simple randomness was used. The number of households to be surveyed was determined indirectly using the Cochrane formula. Data collection in face-to-face mode using a physical questionnaire took place from July 1 to August 31, 2023, after obtaining ethical clearance from the Regional Health Research Ethics Committee, Human from the Center and an administrative authorization for data collection. Regarding their processing, the data was grouped during processing in Excel sheets. Normality and reliability tests of the collected data were carried out. For this, the Chi-square test was used for data with a qualitative value and that of Kolmogorov-Sminorf for data with a quantitative value. Descriptive analysis was possible using R software version 3.2, SPSS version 25.0, XLSTAT 2016, PAST and EXCEL programs from Microsoft Office 2013. Results: The main results highlight economic stress, with 45.60% of households surveyed earning less than US$154 per month;55% of household heads were women in single-parent families;14% of household heads were unemployed, 22% worked in the private sector and 19% were self-employed. This general economic situation leads to precarious living conditions, thereby increasing the risk of high blood pressure among the Cameroonian population.
基金Supported by National Natural Science Foundation of China,No.81874390 and No.81573948Shanghai Natural Science Foundation,No.21ZR1464100+1 种基金Science and Technology Innovation Action Plan of Shanghai Science and Technology Commission,No.22S11901700the Shanghai Key Specialty of Traditional Chinese Clinical Medicine,No.shslczdzk01201.
文摘BACKGROUND Rebleeding after recovery from esophagogastric variceal bleeding(EGVB)is a severe complication that is associated with high rates of both incidence and mortality.Despite its clinical importance,recognized prognostic models that can effectively predict esophagogastric variceal rebleeding in patients with liver cirrhosis are lacking.AIM To construct and externally validate a reliable prognostic model for predicting the occurrence of esophagogastric variceal rebleeding.METHODS This study included 477 EGVB patients across 2 cohorts:The derivation cohort(n=322)and the validation cohort(n=155).The primary outcome was rebleeding events within 1 year.The least absolute shrinkage and selection operator was applied for predictor selection,and multivariate Cox regression analysis was used to construct the prognostic model.Internal validation was performed with bootstrap resampling.We assessed the discrimination,calibration and accuracy of the model,and performed patient risk stratification.RESULTS Six predictors,including albumin and aspartate aminotransferase concentrations,white blood cell count,and the presence of ascites,portal vein thrombosis,and bleeding signs,were selected for the rebleeding event prediction following endoscopic treatment(REPET)model.In predicting rebleeding within 1 year,the REPET model ex-hibited a concordance index of 0.775 and a Brier score of 0.143 in the derivation cohort,alongside 0.862 and 0.127 in the validation cohort.Furthermore,the REPET model revealed a significant difference in rebleeding rates(P<0.01)between low-risk patients and intermediate-to high-risk patients in both cohorts.CONCLUSION We constructed and validated a new prognostic model for variceal rebleeding with excellent predictive per-formance,which will improve the clinical management of rebleeding in EGVB patients.
