The two compartment model with variable extracellular volume is presented and solved by using both perturbation and analytical method. The computation for both creatinine and urea show that the perturbation solution ...The two compartment model with variable extracellular volume is presented and solved by using both perturbation and analytical method. The computation for both creatinine and urea show that the perturbation solution is not only simple but also accurate enough and is a good substitute for the more exact analytical solution.展开更多
There is a need for mesoscale resolution and coupling between flow-field information and the evolution of particle properties in high-shear granulation. We have developed a modelling framework that com- partmentalizes...There is a need for mesoscale resolution and coupling between flow-field information and the evolution of particle properties in high-shear granulation. We have developed a modelling framework that com- partmentalizes the high-shear granulation process based on relevant process parameters in time and space. The model comprises a coupled-flow-field and population-balance solver and is used to resolve and analyze the effects of mesoscales on the evolution of particle properties. A Diosna high-shear mixer was modelled with microcrystalline cellulose powder as the granulation material. An analysis of the flow-field solution and compartmentalization allows for a resolution of the stress and collision peak at the impeller blades. Different compartmentalizations showed the importance of resolving the impeller region, for aggregating systems and systems with breakage. An independent study investigated the time evolution of the flow field by changing the particle properties in three discrete steps that represent pow- der mixing, the initial granulation stage mixing and the late stage granular mixing. The results of the temporal resolution study show clear changes in collision behavior, especially from powder to granular mixing, which indicates the importance of resolving mesoscale phenomena in time and space.展开更多
A two-compartment model of patient-artificial kidney system consisting of a cerebrospinalfluid(CSF)and a body liquor compartments have been presented.With the model,the mechanism ofdisequilibrium syndrome occurred in ...A two-compartment model of patient-artificial kidney system consisting of a cerebrospinalfluid(CSF)and a body liquor compartments have been presented.With the model,the mechanism ofdisequilibrium syndrome occurred in a patient undergoing hemodialysis has been discussed to simulatethe CSF pressure transients.Urea,as an uretic toxin,was injected into dogs and in vivohemodialysis experiments have been performed under clinical conditions.The parameters in the sol-ution,G and K,have been determinde from experiments and are in good agreement with those re-ported under normal physiological conditions and in previous investigations.展开更多
Background:Liqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol-N-hydroxysuccinimide(PEG-NHS).It is designed to prevent cerebrospinal fluid(CSF)leak...Background:Liqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol-N-hydroxysuccinimide(PEG-NHS).It is designed to prevent cerebrospinal fluid(CSF)leakage after intradural surgery.This study assessed the safety and biodegradability of Liqoseal in a porcine craniotomy model.Methods:In 32 pigs a craniotomy plus durotomy was performed.In 15 pigs Liqoseal was implanted,in 11 control pigs no sealant was implanted and in 6 control pigs a control dural sealant(Duraseal or Tachosil)was implanted.The safety of Liqoseal was evaluated by clinical,MRI and histological assessment.The degradation of Liqoseal was histologically estimated.Results:Liqoseal,2 mm thick before application,did not swell and significantly was at maximum mean thickness of 2.14(±0.37)mm at one month.The foreign body reaction induced by Liqoseal,Duraseal and Tachosil were comparable.Liqoseal showed no adherence to the arachnoid layer and was completely resorbed between 6 and 12 months postoperatively.In one animal with Liqoseal,an epidural fluid collection containing CSF could not be excluded.Conclusion:Liqoseal seems to be safe for intracranial use and is biodegradable.The safety and performance in humans needs to be further assessed in clinical trials.展开更多
Dry immersion is an effective and useful model for research in physiology and physiopathology. The focus of this study was to provide integrative insight into renal, endocrine, circulatory, autonomic and metabolic eff...Dry immersion is an effective and useful model for research in physiology and physiopathology. The focus of this study was to provide integrative insight into renal, endocrine, circulatory, autonomic and metabolic effects of dry immersion. We assessed if the principal changes were restored within 24 h of recovery, and determined which changes were mainly associated with immersion-induced orthostatic intolerance. Five-day dry immersion without countermeasures, and with ad libitum water intake, standardized diet and a permitted short daily rise was performed in a relatively large sample for this experiment type (14 healthy young men). Reduction of total body water derived mostly from extracellular compartment, and stabilized rapidly at the new operating point. Decrease in plasma volume was estimated at 20% - 25%. Five-day immersion was sufficient to impair metabolism with a decrease in glucose tolerance and hypercholesterolemia, but was not associated with pronounced autonomic changes. Five-day immersion induced marked cardiovascular impairment. Immediately after immersion, over half of the subjects were unable to accomplish the 20-min 70° tilt;during tilt, heart rate and total peripheral resistance were increased, and stroke volume was decreased. However, 24 hours of normal physical activity appeared sufficient to reverse orthostatic tolerance and all signs of cardiovascular impairment, and to restitute plasma volume and extracellular fluid volume. Similarly, metabolic impairment was restored. In our study, the major factor responsible for orthostatic intolerance appeared to be hypovolemia. The absence of pronounced autonomic dysfunction might be explained by relatively short duration of dry immersion and daily short-time orthostatic stimulation.展开更多
目的基于实验室检查建立儿童细菌性脑膜炎的多项检验指标联合诊断模型。方法回顾性分析2018—2023年惠州市中心人民医院及深圳市儿童医院收治的细菌性脑膜炎(56例)和非细菌性脑膜炎(75例)患儿的16项实验室检验指标。对细菌性脑膜炎与非...目的基于实验室检查建立儿童细菌性脑膜炎的多项检验指标联合诊断模型。方法回顾性分析2018—2023年惠州市中心人民医院及深圳市儿童医院收治的细菌性脑膜炎(56例)和非细菌性脑膜炎(75例)患儿的16项实验室检验指标。对细菌性脑膜炎与非细菌性脑炎患儿的人口学资料(性别、年龄)、临床表现及16项实验室检验指标进行单因素分析。选取单因素分析差异有统计学意义的检验指标进行ROC分析,以曲线下面积(areas under curve,AUC)>0.7作为检验标准,根据β系数的大小对与细菌性脑膜炎独立相关的变量进行排名,利用Logistic线性回归分析将相应变量进行线性拟合,获得新的诊断模型,并选取16例脑膜炎患儿的数据评估模型的诊断效能。结果细菌性脑膜炎和非细菌性脑膜炎患儿的16项检验指标中,12项的差异均有统计学意义(P<0.05)。其中,8项指标的AUC>0.7,包括脑脊液白细胞计数(C-WBC)、脑脊液多核细胞占比(C-PNC%)、脑脊液多核细胞计数(C-PNC)、脑脊液蛋白(C-Pro)、脑脊液乳酸脱氢酶(C-LDH)、血降钙素原(B-PCT)、血清C反应蛋白(B-CRP)、脑脊液葡萄糖/血葡萄糖比值(C/B-Glu)。通过线性拟合获得的诊断模型为:Y=-0.351×C/B Glu+0.561×C-PNC%+0.005×B-PCT+0.001×B-CRP+0.24。拟合模型诊断细菌性脑膜炎的AUC为0.87,灵敏度、特异度均>75%。结论由C/B-Glu、C-PNC%、B-PCT、B-CRP组成的联合模型对儿童细菌性脑膜炎具有良好的诊断价值。展开更多
The residence-time distribution （RTD） and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematic...The residence-time distribution （RTD） and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematical model as well as three-dimensional computational fluid dynamics （CFD） model was established to analyze the flow regions of feedwells on an industrial scale. The concept of RTD, although a well-known method for the characterization of mixing behavior in conventional mixers and reactors, is still a novel measure for the characterization of mixing in feedwells. Numerical simulation results show that the inlet feed rate and the aspect ratio of feedwells are the most critical parameters which affect the RTD of feedwell. Further simulation experiments were then carried out. Under the optimal operation conditions, the volume fraction of dead zone can reduce by10.8% and an increasement of mixing flow volume fraction by 6.5% is also observed. There is an optimum feed inlet rate depending on the feedwell design. The CFD model in conjunction with the RTD analysis then can be used as an effective tool in the design, evaluation and optimization of thickener feedwell in the red mud separation.展开更多
文摘The two compartment model with variable extracellular volume is presented and solved by using both perturbation and analytical method. The computation for both creatinine and urea show that the perturbation solution is not only simple but also accurate enough and is a good substitute for the more exact analytical solution.
文摘There is a need for mesoscale resolution and coupling between flow-field information and the evolution of particle properties in high-shear granulation. We have developed a modelling framework that com- partmentalizes the high-shear granulation process based on relevant process parameters in time and space. The model comprises a coupled-flow-field and population-balance solver and is used to resolve and analyze the effects of mesoscales on the evolution of particle properties. A Diosna high-shear mixer was modelled with microcrystalline cellulose powder as the granulation material. An analysis of the flow-field solution and compartmentalization allows for a resolution of the stress and collision peak at the impeller blades. Different compartmentalizations showed the importance of resolving the impeller region, for aggregating systems and systems with breakage. An independent study investigated the time evolution of the flow field by changing the particle properties in three discrete steps that represent pow- der mixing, the initial granulation stage mixing and the late stage granular mixing. The results of the temporal resolution study show clear changes in collision behavior, especially from powder to granular mixing, which indicates the importance of resolving mesoscale phenomena in time and space.
文摘A two-compartment model of patient-artificial kidney system consisting of a cerebrospinalfluid(CSF)and a body liquor compartments have been presented.With the model,the mechanism ofdisequilibrium syndrome occurred in a patient undergoing hemodialysis has been discussed to simulatethe CSF pressure transients.Urea,as an uretic toxin,was injected into dogs and in vivohemodialysis experiments have been performed under clinical conditions.The parameters in the sol-ution,G and K,have been determinde from experiments and are in good agreement with those re-ported under normal physiological conditions and in previous investigations.
文摘Background:Liqoseal consists of a watertight layer of poly(ester)ether urethane and an adhesive layer containing polyethylene glycol-N-hydroxysuccinimide(PEG-NHS).It is designed to prevent cerebrospinal fluid(CSF)leakage after intradural surgery.This study assessed the safety and biodegradability of Liqoseal in a porcine craniotomy model.Methods:In 32 pigs a craniotomy plus durotomy was performed.In 15 pigs Liqoseal was implanted,in 11 control pigs no sealant was implanted and in 6 control pigs a control dural sealant(Duraseal or Tachosil)was implanted.The safety of Liqoseal was evaluated by clinical,MRI and histological assessment.The degradation of Liqoseal was histologically estimated.Results:Liqoseal,2 mm thick before application,did not swell and significantly was at maximum mean thickness of 2.14(±0.37)mm at one month.The foreign body reaction induced by Liqoseal,Duraseal and Tachosil were comparable.Liqoseal showed no adherence to the arachnoid layer and was completely resorbed between 6 and 12 months postoperatively.In one animal with Liqoseal,an epidural fluid collection containing CSF could not be excluded.Conclusion:Liqoseal seems to be safe for intracranial use and is biodegradable.The safety and performance in humans needs to be further assessed in clinical trials.
文摘Dry immersion is an effective and useful model for research in physiology and physiopathology. The focus of this study was to provide integrative insight into renal, endocrine, circulatory, autonomic and metabolic effects of dry immersion. We assessed if the principal changes were restored within 24 h of recovery, and determined which changes were mainly associated with immersion-induced orthostatic intolerance. Five-day dry immersion without countermeasures, and with ad libitum water intake, standardized diet and a permitted short daily rise was performed in a relatively large sample for this experiment type (14 healthy young men). Reduction of total body water derived mostly from extracellular compartment, and stabilized rapidly at the new operating point. Decrease in plasma volume was estimated at 20% - 25%. Five-day immersion was sufficient to impair metabolism with a decrease in glucose tolerance and hypercholesterolemia, but was not associated with pronounced autonomic changes. Five-day immersion induced marked cardiovascular impairment. Immediately after immersion, over half of the subjects were unable to accomplish the 20-min 70° tilt;during tilt, heart rate and total peripheral resistance were increased, and stroke volume was decreased. However, 24 hours of normal physical activity appeared sufficient to reverse orthostatic tolerance and all signs of cardiovascular impairment, and to restitute plasma volume and extracellular fluid volume. Similarly, metabolic impairment was restored. In our study, the major factor responsible for orthostatic intolerance appeared to be hypovolemia. The absence of pronounced autonomic dysfunction might be explained by relatively short duration of dry immersion and daily short-time orthostatic stimulation.
文摘目的基于实验室检查建立儿童细菌性脑膜炎的多项检验指标联合诊断模型。方法回顾性分析2018—2023年惠州市中心人民医院及深圳市儿童医院收治的细菌性脑膜炎(56例)和非细菌性脑膜炎(75例)患儿的16项实验室检验指标。对细菌性脑膜炎与非细菌性脑炎患儿的人口学资料(性别、年龄)、临床表现及16项实验室检验指标进行单因素分析。选取单因素分析差异有统计学意义的检验指标进行ROC分析,以曲线下面积(areas under curve,AUC)>0.7作为检验标准,根据β系数的大小对与细菌性脑膜炎独立相关的变量进行排名,利用Logistic线性回归分析将相应变量进行线性拟合,获得新的诊断模型,并选取16例脑膜炎患儿的数据评估模型的诊断效能。结果细菌性脑膜炎和非细菌性脑膜炎患儿的16项检验指标中,12项的差异均有统计学意义(P<0.05)。其中,8项指标的AUC>0.7,包括脑脊液白细胞计数(C-WBC)、脑脊液多核细胞占比(C-PNC%)、脑脊液多核细胞计数(C-PNC)、脑脊液蛋白(C-Pro)、脑脊液乳酸脱氢酶(C-LDH)、血降钙素原(B-PCT)、血清C反应蛋白(B-CRP)、脑脊液葡萄糖/血葡萄糖比值(C/B-Glu)。通过线性拟合获得的诊断模型为:Y=-0.351×C/B Glu+0.561×C-PNC%+0.005×B-PCT+0.001×B-CRP+0.24。拟合模型诊断细菌性脑膜炎的AUC为0.87,灵敏度、特异度均>75%。结论由C/B-Glu、C-PNC%、B-PCT、B-CRP组成的联合模型对儿童细菌性脑膜炎具有良好的诊断价值。
基金Project (50876116) supported by the National Natural Science Foundation of China
文摘The residence-time distribution （RTD） and the compartment model were applied to characterizing the flow regions in red mud separation thickener’s feedwells. Combined with the experimental work, validated mathematical model as well as three-dimensional computational fluid dynamics （CFD） model was established to analyze the flow regions of feedwells on an industrial scale. The concept of RTD, although a well-known method for the characterization of mixing behavior in conventional mixers and reactors, is still a novel measure for the characterization of mixing in feedwells. Numerical simulation results show that the inlet feed rate and the aspect ratio of feedwells are the most critical parameters which affect the RTD of feedwell. Further simulation experiments were then carried out. Under the optimal operation conditions, the volume fraction of dead zone can reduce by10.8% and an increasement of mixing flow volume fraction by 6.5% is also observed. There is an optimum feed inlet rate depending on the feedwell design. The CFD model in conjunction with the RTD analysis then can be used as an effective tool in the design, evaluation and optimization of thickener feedwell in the red mud separation.
