Objective Most patients with knee osteoarthritis(OA)have alignment deformity with the change of Hip-knee-ankle(HKA)angle.The knee alignment influences load distribution at the tibial plateau.Meanwhile,change of subcho...Objective Most patients with knee osteoarthritis(OA)have alignment deformity with the change of Hip-knee-ankle(HKA)angle.The knee alignment influences load distribution at the tibial plateau.Meanwhile,change of subchondral trabecular bone microstructure is related to load bearing and OA progression.However,the relationship between knee alignment on the changes of subchondral trabecular bone microstructure and OA severity have been poorly investigated.The main goal of this work was to investigate variation in tibial plateaus subchondral trabecular bone microstructure in knee OA patients and their association with the severity of OA with the change of knee alignment.Methods Seventy-one knee OA patients planning to undergo total knee arthroplasty were enrolled in this study.The HKA angle and OA disease severity(OARSI score,compartment-specific Kellgren-Lawrence(K-L)grade and OARSI Atlas grade)based on full-leg standing posteroanterior radiographs were evaluated preoperatively in all patients.The tibial plateau collected during surgery was first used for micro-computed tomography(μCT)to analyze the subchondral trabecular bone microstructures,and then used for pathological sections to analyze cartilage degeneration(OARSI score).Pearson and spearman correlations were used to examine linear relationships between knee alignment,OA disease severity and subchondral trabecular bone microstructure.Patients were then divided into group I(HKA angle exceeds 0°in the valgus direction),group II(varus angle<10°)and group III(varus angle≥10°).The differences in subchondral trabecular bone microstructural parameters between the three groups were analyzed by the one-way ANOVA with a post hoc Tukey test.Results HKA angle was significantly correlated with all tibial plateau subchondral trabecular bone microstructure parameters.Regardless of the medial or lateral tibia,HKA angle was most strongly correlated with bone volume fraction(BV/TV),M:(r=0. 613,P<0.01);L:(r=-0.490,P<0.01).In addition,for the media-to-lateral ratios(M:L)of the subchondral trabecular bone microstructure parameters,the HKA angle is positively correlated with M:L BV/TV(r=0.658,P<0.01),M:L trabecular number(Tb.N)(r=0.525,,P<0.01),M:L trabecular thickness(Tb.Th)(r=0.636,P<0.01),and negatively correlated with M:L trabecular separation(Tb.Sp)(r=-0.636,P<0.01)and M:L Specific Bone Surface(BS/BV)(r=-0.792,P<0.01).The BV/TV,Tb.N,and Tb.Th of the medial tibia were sequentially incremented in the order of groupⅠ,Ⅱ,Ⅲof knee alignment,while the Tb.Sp and BS/BV were decreased in this order.The lateral tibia is the opposite.In addition,most of the severity indices of OA are associated with subchondral trabecular bone microstructures,of which OARSI score and BV/TV in medial tibia are the most relevant(r=0.787,P<0.01).HKA angle is significantly correlated with all OA severity grades in medial compartment,but only with OARSI score and Bone sclerosis grade in lateral compartment.Conclusions Tibial plateau subchondral trabecular bone microarchitecture is associated with the HKA angle and OA severity.With the increase of varus angle and the severity of OA,the subchondral trabecular bone in medial tibia has more obvious sclerosis changes and vice versa,suggesting that knee malalignment may promote abnormal subchondral trabecular bone remodeling by altering joint load distribution,thereby affecting the progression of OA.展开更多
Vibration monitoring and vibration severity evaluation of armored vehicle transmission are realized by additional sensors. An algorithm of vibration severity in frequency domain is presented. The algorithm has powerfu...Vibration monitoring and vibration severity evaluation of armored vehicle transmission are realized by additional sensors. An algorithm of vibration severity in frequency domain is presented. The algorithm has powerful applicability for signal type and flexible selectivity for frequency range,and avoids the processing of signal conversion used calculus and filtering compared to the algorithm of vibration severity in time domain. An applied example is given in company with attentive proceedings and measures for improving evaluation effect.展开更多
RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorl...RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorly understood,particularly at varying dust concentrations.This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations(300 g/m^(3),600 g/m^(3),900 g/m^(3))on RDX dust explosion severity,flame propagation behavior,and gaseous products.The results indicate that the maximum explosion pressure peaks at 35%RDX,65%RDX,and 80%RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Concurrently,the time for the flame to propagate to the wall(t1)reaches minimum values of 34.8 ms,25.66 ms,and 23.93 ms.The maximum rate of pressure rise is observed for pure RDX at 900 g/m^(3).Aluminum powder enhances flame propagation velocity and combustion duration,as validated by the flame propagation system.Overall,the concentrations of carbon oxides(CO+CO_(2))decrease significantly with increasing aluminum mass percentage.At 20%RDX,the concentrations decreased by 51.64%,72.31%,and 79.55%compared to pure RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Notably,N_(2)O concentration only at 300 g/m^(3)showed such a trend.It rises first and then falls at 35%RDX at 600 g/m^(3)and 900 g/m^(3).These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.展开更多
Objective:Augmented renal clearance(ARC),in contrast to renal dysfunction,refers to enhanced renal elimination of circulating solutes compared to the expected baseline.Although patients may present with normal serum c...Objective:Augmented renal clearance(ARC),in contrast to renal dysfunction,refers to enhanced renal elimination of circulating solutes compared to the expected baseline.Although patients may present with normal serum creatinine(Scr)levels,the incidence of ARC is high in intensive care unit(ICU)settings.ARC is associated with subtherapeutic exposure and treatment failure of renally cleared antibiotics.However,limited research exists on the incidence and risk factors of ARC in the ICU,and even fewer data are available specifically for neurological ICU(NICU).This study aims to determine the incidence and risk factors of ARC in neurocritically ill patients.Methods:We retrospectively analyzed all available Scr data of neurocritical care patients admitted to the NICU of the Second Xiangya Hospital of Central South University between December 2020 and January 2023.Creatinine clearance(CrCl)was calculated using the Cockcroft-Gault equation.ARC was defined as a CrCl≥130 mL/(min·1.73 m^(2))sustained for more than 50%of the duration of the NICU stay.A total of 208 neurocritically ill patients were assigned into an ARC group(n=52)and a non-ARC(N-ARC)group(n=156).Clinical characteristics were compared between the 2 groups.Variables with P<0.05 in univariate analysis were included in binary Logistic regression to identify independent risk factors for ARC.Results:The incidence of ARC among neurocritically ill patients was 25.00%.Of the 74 patients with normal CrCl,20(27.03%)gradually developed ARC during hospitalization.Compared with the N-ARC group,the patients of the ARC group were younger(P<0.001),with a higher proportion of females(P=0.048)and a lower admission mean arterial pressure(MAP)(P=0.034).Moreover,patients of the ARC group were commonly complicated with severe bacterial infections compared with the patients of the N-ARC group(P<0.001).In binary Logistic regression analysis,younger age(OR=0.903,95%CI 0.872 to 0.935)and severe bacterial infections(OR=6.270,95%CI 2.568 to 15.310)were significant predictors of ARC.Conclusion:ARC is relatively common in the NICU.A considerable number of patients with initially normal renal function developed ARC during hospitalization.Younger age and concurrent severe bacterial infection are important risk factors of ARC in neurocritically ill patients.展开更多
随着世界各国步入老龄化社会,越来越多的老龄患者因结直肠恶性肿瘤而需要外科治疗,如何评价患者的身体条件及预测手术风险,一直是外科医生重点关注的问题。英国Copeland等[1]1991年建立病死率和并发症率的生理学及手术严重性评分（physi...随着世界各国步入老龄化社会,越来越多的老龄患者因结直肠恶性肿瘤而需要外科治疗,如何评价患者的身体条件及预测手术风险,一直是外科医生重点关注的问题。英国Copeland等[1]1991年建立病死率和并发症率的生理学及手术严重性评分（physiological and operative severity score for the enumeration of mortality and morbidity,简称POSSUM）,预测术后病死率和并发症发生率。展开更多
讨论了基于SQL Sever 2000数据库、B/S模型构建的矿山安全生产信息系统的开发,该系统采用自顶而下、不断迭代和优化的开发策略,能够实时、动态存储和管理安全、生产等信息,并使得这些信息实现共享,提高生产、安全和质量管理的决策科学...讨论了基于SQL Sever 2000数据库、B/S模型构建的矿山安全生产信息系统的开发,该系统采用自顶而下、不断迭代和优化的开发策略,能够实时、动态存储和管理安全、生产等信息,并使得这些信息实现共享,提高生产、安全和质量管理的决策科学性与实时处理问题的能力。展开更多
Although extensive analyses of road segments and intersections located in urban road networks have examined the role of many factors that contribute to the frequency and severity of crashes, the explicit relationship ...Although extensive analyses of road segments and intersections located in urban road networks have examined the role of many factors that contribute to the frequency and severity of crashes, the explicit relationship between street pattern characteristics and traffic safety remains underexplored. Based on a zone-based Hong Kong database, the Space Syntax was used to quantify the topological characteristics of street patterns and investigate the role of street patterns and zone-related factors in zone-based traffic safety analysis. A joint probability model was adopted to analyze crash frequency and severity in an integrated modeling framework and the maximum likelihood estimation method was used to estimate the parameters. In addition to the characteristics of street patterns, speed, road geometry, land-use patterns, and temporal factors were considered. The vehicle hours was also included as an exposure proxy in the model to make crash frequency predictions. The results indicate that the joint probability model can reveal the relationship between zone-based traffic safety and various other factors, and that street pattern characteristics play an important role in crash frequency prediction.展开更多
Measuring the dust explosion characteristics of aluminum-based activated fuels was a prerequisite for developing effective prevention and control measures.In this paper,ignition sensitivity,flame propagation behaviors...Measuring the dust explosion characteristics of aluminum-based activated fuels was a prerequisite for developing effective prevention and control measures.In this paper,ignition sensitivity,flame propagation behaviors and explosion severity of aluminum/polytetrafluoroethylene(Al/PTFE)compositions including 2 PT(2.80 wt.%F),4 PT(7.18 wt.%F)and 8 PT(11.90 wt.%F)were studied.When the content of F increased from 2.80 wt.%to 11.90 wt.%,the minimum explosive concentration MEC decreased from380 g/m^(3)to 140 g/m^(3),due to the dual effects of increased internal active aluminum and enhanced reactivity.The average flame propagation velocities increased as the percentage of F increased.The maximum explosion pressure Pmof 500 g/m3aluminum-based activated fuels increased from 247 k Pa to299 kPa.Scanning electron microscopy demonstrated that with the increase of PTFE content,the reaction was more complete.On this basis,the explosion mechanism of aluminum-based activated fuels was revealed.展开更多
介绍了一个基于client/sever结构,前端应用程序使用DELPHI 5.0作为开发工具,后台使用Microsoft SQL SERVER 7.0作为数据库支持的教师评测软件系统的设计与实现方法。通过对教师自评、专家评价和学生评价的评价数据采集、模糊评测分析...介绍了一个基于client/sever结构,前端应用程序使用DELPHI 5.0作为开发工具,后台使用Microsoft SQL SERVER 7.0作为数据库支持的教师评测软件系统的设计与实现方法。通过对教师自评、专家评价和学生评价的评价数据采集、模糊评测分析和统计,实现了对教师教学工作的全面、准确、科学的评价,同时该系统还具备教师信息查询、打印、数据库维护等功能,实现教师信息管理的无纸化办公。展开更多
基金supported by grants from the National Natural Science Foundation of China ( 11572197, 11872251)Shanghai Clinical Medical Center ( 2017ZZ01023)+1 种基金Shanghai Municipal Key Clinical Specialty,Shanghai Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine ( JYLJ201821,CK2018011)Shanghai Jiao Tong University School of Medicine ( TM201814)
文摘Objective Most patients with knee osteoarthritis(OA)have alignment deformity with the change of Hip-knee-ankle(HKA)angle.The knee alignment influences load distribution at the tibial plateau.Meanwhile,change of subchondral trabecular bone microstructure is related to load bearing and OA progression.However,the relationship between knee alignment on the changes of subchondral trabecular bone microstructure and OA severity have been poorly investigated.The main goal of this work was to investigate variation in tibial plateaus subchondral trabecular bone microstructure in knee OA patients and their association with the severity of OA with the change of knee alignment.Methods Seventy-one knee OA patients planning to undergo total knee arthroplasty were enrolled in this study.The HKA angle and OA disease severity(OARSI score,compartment-specific Kellgren-Lawrence(K-L)grade and OARSI Atlas grade)based on full-leg standing posteroanterior radiographs were evaluated preoperatively in all patients.The tibial plateau collected during surgery was first used for micro-computed tomography(μCT)to analyze the subchondral trabecular bone microstructures,and then used for pathological sections to analyze cartilage degeneration(OARSI score).Pearson and spearman correlations were used to examine linear relationships between knee alignment,OA disease severity and subchondral trabecular bone microstructure.Patients were then divided into group I(HKA angle exceeds 0°in the valgus direction),group II(varus angle<10°)and group III(varus angle≥10°).The differences in subchondral trabecular bone microstructural parameters between the three groups were analyzed by the one-way ANOVA with a post hoc Tukey test.Results HKA angle was significantly correlated with all tibial plateau subchondral trabecular bone microstructure parameters.Regardless of the medial or lateral tibia,HKA angle was most strongly correlated with bone volume fraction(BV/TV),M:(r=0. 613,P<0.01);L:(r=-0.490,P<0.01).In addition,for the media-to-lateral ratios(M:L)of the subchondral trabecular bone microstructure parameters,the HKA angle is positively correlated with M:L BV/TV(r=0.658,P<0.01),M:L trabecular number(Tb.N)(r=0.525,,P<0.01),M:L trabecular thickness(Tb.Th)(r=0.636,P<0.01),and negatively correlated with M:L trabecular separation(Tb.Sp)(r=-0.636,P<0.01)and M:L Specific Bone Surface(BS/BV)(r=-0.792,P<0.01).The BV/TV,Tb.N,and Tb.Th of the medial tibia were sequentially incremented in the order of groupⅠ,Ⅱ,Ⅲof knee alignment,while the Tb.Sp and BS/BV were decreased in this order.The lateral tibia is the opposite.In addition,most of the severity indices of OA are associated with subchondral trabecular bone microstructures,of which OARSI score and BV/TV in medial tibia are the most relevant(r=0.787,P<0.01).HKA angle is significantly correlated with all OA severity grades in medial compartment,but only with OARSI score and Bone sclerosis grade in lateral compartment.Conclusions Tibial plateau subchondral trabecular bone microarchitecture is associated with the HKA angle and OA severity.With the increase of varus angle and the severity of OA,the subchondral trabecular bone in medial tibia has more obvious sclerosis changes and vice versa,suggesting that knee malalignment may promote abnormal subchondral trabecular bone remodeling by altering joint load distribution,thereby affecting the progression of OA.
基金Sponsored by National Defense Science and Technology Key Lab Foundation of China (51457120104JB3505)
文摘Vibration monitoring and vibration severity evaluation of armored vehicle transmission are realized by additional sensors. An algorithm of vibration severity in frequency domain is presented. The algorithm has powerful applicability for signal type and flexible selectivity for frequency range,and avoids the processing of signal conversion used calculus and filtering compared to the algorithm of vibration severity in time domain. An applied example is given in company with attentive proceedings and measures for improving evaluation effect.
基金the financial support of the Shanxi Fire&Explosion-Proofing Safety Engineering and Technology Research Center,North University of China。
文摘RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorly understood,particularly at varying dust concentrations.This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations(300 g/m^(3),600 g/m^(3),900 g/m^(3))on RDX dust explosion severity,flame propagation behavior,and gaseous products.The results indicate that the maximum explosion pressure peaks at 35%RDX,65%RDX,and 80%RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Concurrently,the time for the flame to propagate to the wall(t1)reaches minimum values of 34.8 ms,25.66 ms,and 23.93 ms.The maximum rate of pressure rise is observed for pure RDX at 900 g/m^(3).Aluminum powder enhances flame propagation velocity and combustion duration,as validated by the flame propagation system.Overall,the concentrations of carbon oxides(CO+CO_(2))decrease significantly with increasing aluminum mass percentage.At 20%RDX,the concentrations decreased by 51.64%,72.31%,and 79.55%compared to pure RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Notably,N_(2)O concentration only at 300 g/m^(3)showed such a trend.It rises first and then falls at 35%RDX at 600 g/m^(3)and 900 g/m^(3).These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.
基金supported by the Natural Science Foundation of Hunan Province(2023JJ60087)the Clinical Medical Technology Innovation Guidance Project of Hunan Province(2021SK53501),China。
文摘Objective:Augmented renal clearance(ARC),in contrast to renal dysfunction,refers to enhanced renal elimination of circulating solutes compared to the expected baseline.Although patients may present with normal serum creatinine(Scr)levels,the incidence of ARC is high in intensive care unit(ICU)settings.ARC is associated with subtherapeutic exposure and treatment failure of renally cleared antibiotics.However,limited research exists on the incidence and risk factors of ARC in the ICU,and even fewer data are available specifically for neurological ICU(NICU).This study aims to determine the incidence and risk factors of ARC in neurocritically ill patients.Methods:We retrospectively analyzed all available Scr data of neurocritical care patients admitted to the NICU of the Second Xiangya Hospital of Central South University between December 2020 and January 2023.Creatinine clearance(CrCl)was calculated using the Cockcroft-Gault equation.ARC was defined as a CrCl≥130 mL/(min·1.73 m^(2))sustained for more than 50%of the duration of the NICU stay.A total of 208 neurocritically ill patients were assigned into an ARC group(n=52)and a non-ARC(N-ARC)group(n=156).Clinical characteristics were compared between the 2 groups.Variables with P<0.05 in univariate analysis were included in binary Logistic regression to identify independent risk factors for ARC.Results:The incidence of ARC among neurocritically ill patients was 25.00%.Of the 74 patients with normal CrCl,20(27.03%)gradually developed ARC during hospitalization.Compared with the N-ARC group,the patients of the ARC group were younger(P<0.001),with a higher proportion of females(P=0.048)and a lower admission mean arterial pressure(MAP)(P=0.034).Moreover,patients of the ARC group were commonly complicated with severe bacterial infections compared with the patients of the N-ARC group(P<0.001).In binary Logistic regression analysis,younger age(OR=0.903,95%CI 0.872 to 0.935)and severe bacterial infections(OR=6.270,95%CI 2.568 to 15.310)were significant predictors of ARC.Conclusion:ARC is relatively common in the NICU.A considerable number of patients with initially normal renal function developed ARC during hospitalization.Younger age and concurrent severe bacterial infection are important risk factors of ARC in neurocritically ill patients.
文摘随着世界各国步入老龄化社会,越来越多的老龄患者因结直肠恶性肿瘤而需要外科治疗,如何评价患者的身体条件及预测手术风险,一直是外科医生重点关注的问题。英国Copeland等[1]1991年建立病死率和并发症率的生理学及手术严重性评分（physiological and operative severity score for the enumeration of mortality and morbidity,简称POSSUM）,预测术后病死率和并发症发生率。
基金Project(71301083)supported by the National Natural Science Foundation of ChinaProject(2012AA112305)supported by the National High-Tech Research and Development Program of China+1 种基金Project(2012CB725405)supported by the National Basic Research Program of ChinaProject(17208614)supported by the Research Grants Council of the Hong Kong Special Administrative Region,China
文摘Although extensive analyses of road segments and intersections located in urban road networks have examined the role of many factors that contribute to the frequency and severity of crashes, the explicit relationship between street pattern characteristics and traffic safety remains underexplored. Based on a zone-based Hong Kong database, the Space Syntax was used to quantify the topological characteristics of street patterns and investigate the role of street patterns and zone-related factors in zone-based traffic safety analysis. A joint probability model was adopted to analyze crash frequency and severity in an integrated modeling framework and the maximum likelihood estimation method was used to estimate the parameters. In addition to the characteristics of street patterns, speed, road geometry, land-use patterns, and temporal factors were considered. The vehicle hours was also included as an exposure proxy in the model to make crash frequency predictions. The results indicate that the joint probability model can reveal the relationship between zone-based traffic safety and various other factors, and that street pattern characteristics play an important role in crash frequency prediction.
基金financially supported by National Natural Science Foundation of China(No.51922025 and No.51874066)China Postdoctoral Science Foundation(No.2020M670759)the Fundamental Research Funds for the Central Universities(No.DUT20GJ201)。
文摘Measuring the dust explosion characteristics of aluminum-based activated fuels was a prerequisite for developing effective prevention and control measures.In this paper,ignition sensitivity,flame propagation behaviors and explosion severity of aluminum/polytetrafluoroethylene(Al/PTFE)compositions including 2 PT(2.80 wt.%F),4 PT(7.18 wt.%F)and 8 PT(11.90 wt.%F)were studied.When the content of F increased from 2.80 wt.%to 11.90 wt.%,the minimum explosive concentration MEC decreased from380 g/m^(3)to 140 g/m^(3),due to the dual effects of increased internal active aluminum and enhanced reactivity.The average flame propagation velocities increased as the percentage of F increased.The maximum explosion pressure Pmof 500 g/m3aluminum-based activated fuels increased from 247 k Pa to299 kPa.Scanning electron microscopy demonstrated that with the increase of PTFE content,the reaction was more complete.On this basis,the explosion mechanism of aluminum-based activated fuels was revealed.
文摘介绍了一个基于client/sever结构,前端应用程序使用DELPHI 5.0作为开发工具,后台使用Microsoft SQL SERVER 7.0作为数据库支持的教师评测软件系统的设计与实现方法。通过对教师自评、专家评价和学生评价的评价数据采集、模糊评测分析和统计,实现了对教师教学工作的全面、准确、科学的评价,同时该系统还具备教师信息查询、打印、数据库维护等功能,实现教师信息管理的无纸化办公。
