A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous ...A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.展开更多
BACKGROUND Neurological complications are common in the management of venoarterial extracorporeal membrane oxygenation(VA-ECMO),with most patients requiring sedation and intubation,limiting the assessment of neurologi...BACKGROUND Neurological complications are common in the management of venoarterial extracorporeal membrane oxygenation(VA-ECMO),with most patients requiring sedation and intubation,limiting the assessment of neurological function.Therefore,we must rely on advanced neuroimaging techniques,such as computed tomography angiography(CTA)and computed tomography perfusion(CTP).Because ECMO changes the normal blood flow pattern,it may interfere with the contrast medium in some special cases,leading to artifacts and ultimately misleading clinical decisions.CASE SUMMARY A 61-year-old man presented to a local hospital with chest tightness and pain 1 d prior to presentation.The patient was treated with VA-ECMO after sudden cardiac and respiratory arrest at a local hospital.For further treatment,the patient was transferred to our hospital.The initial consciousness assessment was not clear,and routine CTP was performed to understand the intracranial changes,which suggested a large area of cerebral infarction on the right side;however,the cerebral oxygen was not consistent with the CTP results,and the reexamination of CTA still suggested a right cerebral infarction.To identify this difference,bedside transcranial Doppler was performed,and the blood flow on both sides was different.By reducing the ECMO flow,CTP reexamination showed that the results were normal and consistent with the clinical results.On day 3,the patient was alert and showed good limb movements.CONCLUSION In patients with peripheral VA-ECMO,cerebral perfusion confirmed by CTP and CTA may lead to false cerebral infarction.展开更多
With the rapid increase of water contamination,membrane separation technology and their corresponding molecular weight cut-off(MWCO) evaluation method become more necessary.In this study,Panax notoginseng saponins was...With the rapid increase of water contamination,membrane separation technology and their corresponding molecular weight cut-off(MWCO) evaluation method become more necessary.In this study,Panax notoginseng saponins was used as a new standard marker to determinate ultrafiltration(UF) membrane MWCOs,series of Millipore membranes were selected as control group to analyze and calculate the relationship between retention rate and MWCOs with exponential or logarithmic equation.A new and convenient method was provided for determining the membrane MWCO by modeling analysis retention rate with MWCOs,and the regression coefficients >0.990.The feasibility and practicability of established method was verified by different manufactures' membrane and dextrans.In the detection progress,as the main ingredient of Panax notoginseng saponins,Notoginsenoside R_1,Ginsenoside Rg_1,Ginsenoside Rb_1 and Ginsenoside Rd with different surface activity,the MWCO range of UF membranes can be divided into two zones mainly due to the retention rate difference among Notoginsenoside R_1,Ginsenoside Rg_1,Ginsenoside Rb_1 and Ginsenoside Rd.Zone 1,1000-10000;and Zone II,10000-100000.Thus,the new method would be helpful to improve the applicability of UF membrane in separation technology.展开更多
An optimal medium （300 g·L^-1 initial glucose） comprising 6.3 mmol·L^-1 Mg2＋, 5.0 mmol·L^-1 Ca2＋, 15.0 g·L^-1 peptone and 21.5 g·L^-1 yeast extract was determined by uniform design to impr...An optimal medium （300 g·L^-1 initial glucose） comprising 6.3 mmol·L^-1 Mg2＋, 5.0 mmol·L^-1 Ca2＋, 15.0 g·L^-1 peptone and 21.5 g·L^-1 yeast extract was determined by uniform design to improve very high gravity （VHG） ethanol fermentation, showing over 30% increase in final ethanol （from 13.1% to 17.1%, by volume）, 29% decrease in fermentation time （from 84 to 60 h）, 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.展开更多
Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (B...Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (BKC) has an inhibitory effect on many bacteria but it has no significant effect on Pseudomonas aeruginosa. Cetrimide agar medium is recommended for the isolation and enumeration of Ps. aeruginosa in food and environmental samples. However, there are claims that for some food factories and in particular the bottled water industry, the selectivity of this medium is not sufficient. The aim of the current research is the creation of a more selective medium for Ps. aeruginosa with BKC. A total of 28 isolates were isolated with Cetrimide agar from raw water samples and identified using biochemical tests and commercial identification kits. All the bacteria were inoculated in Cetrimide agar plates containing 0 - 625 μg/mL BKC. The Petri dishes were incubated at 37°C and 42°C for 24 h. The results showed that 375 μg/mL BKC was sufficient to suppress Burk. pseudomallei at both incubation temperatures. Ps. fluorescens-35 could not grow at 42°C at any concentration, including the control, and was suppressed at 500 μg/mL BKC. All the Ps. aeruginosa isolates and control strain were grown at both incubation temperatures at 375 μg/mL BKC concentration. In conclusion, the analysis of Ps. aeruginosa showed that the growth of accompanying flora may be suppressed by adding 375-μg/mL BKC into Cetrimide agar and incubating at an elevated temperature of 42°C.展开更多
目的探讨胰蛋白胨葡萄糖培养基(TGEA)法和营养琼脂法对内镜终末漂洗水的监测效果,以及比较试剂盒过滤集菌法和传统过滤集菌法对内镜消毒质量的监测效果。方法调查天津市24家医疗机构内镜中心基本信息,随机抽取终末漂洗水及内镜管腔冲洗...目的探讨胰蛋白胨葡萄糖培养基(TGEA)法和营养琼脂法对内镜终末漂洗水的监测效果,以及比较试剂盒过滤集菌法和传统过滤集菌法对内镜消毒质量的监测效果。方法调查天津市24家医疗机构内镜中心基本信息,随机抽取终末漂洗水及内镜管腔冲洗水水样,分别采用两种方法检测细菌菌落数。结果 TGEA法对终末漂洗水监测所得检出率(96.7% vs 73.3%)、菌落数(中位数44 CFU/100 ml vs 8 CFU/100 ml)均高于营养琼脂法,差异有统计学意义(P <0.05),Bland-Altman分析显示两方法一致性较差;试剂盒过滤集菌法和传统过滤集菌法监测内镜消毒质量检出率(60.0%vs 56.7%)及菌落数(中位数2 CFU/件vs 1 CFU/件)相近,差异无统计学意义(P>0.05),Bland-Altman分析显示两方法一致性较好。结论被调查单位对终末漂洗水及内镜消毒质量的监测水平较低、采用检测方法规范性差。TGEA法对终末漂洗水检测更具敏感性、临床适应性强,试剂盒过滤集菌法操作简单、快捷、高效、准确,两种方法均适合内镜中心的日常监测。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50779012)
文摘A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.
文摘BACKGROUND Neurological complications are common in the management of venoarterial extracorporeal membrane oxygenation(VA-ECMO),with most patients requiring sedation and intubation,limiting the assessment of neurological function.Therefore,we must rely on advanced neuroimaging techniques,such as computed tomography angiography(CTA)and computed tomography perfusion(CTP).Because ECMO changes the normal blood flow pattern,it may interfere with the contrast medium in some special cases,leading to artifacts and ultimately misleading clinical decisions.CASE SUMMARY A 61-year-old man presented to a local hospital with chest tightness and pain 1 d prior to presentation.The patient was treated with VA-ECMO after sudden cardiac and respiratory arrest at a local hospital.For further treatment,the patient was transferred to our hospital.The initial consciousness assessment was not clear,and routine CTP was performed to understand the intracranial changes,which suggested a large area of cerebral infarction on the right side;however,the cerebral oxygen was not consistent with the CTP results,and the reexamination of CTA still suggested a right cerebral infarction.To identify this difference,bedside transcranial Doppler was performed,and the blood flow on both sides was different.By reducing the ECMO flow,CTP reexamination showed that the results were normal and consistent with the clinical results.On day 3,the patient was alert and showed good limb movements.CONCLUSION In patients with peripheral VA-ECMO,cerebral perfusion confirmed by CTP and CTA may lead to false cerebral infarction.
基金Supported by the National Natural Science Foundation of China(No.81503258,No.81373980)Youth Natural Science Foundation of Jiangsu Province(No.BK20151005)Science and Technology Project of Jiangsu Traditional Chinese Medicine Administration(No.YB2015009)
文摘With the rapid increase of water contamination,membrane separation technology and their corresponding molecular weight cut-off(MWCO) evaluation method become more necessary.In this study,Panax notoginseng saponins was used as a new standard marker to determinate ultrafiltration(UF) membrane MWCOs,series of Millipore membranes were selected as control group to analyze and calculate the relationship between retention rate and MWCOs with exponential or logarithmic equation.A new and convenient method was provided for determining the membrane MWCO by modeling analysis retention rate with MWCOs,and the regression coefficients >0.990.The feasibility and practicability of established method was verified by different manufactures' membrane and dextrans.In the detection progress,as the main ingredient of Panax notoginseng saponins,Notoginsenoside R_1,Ginsenoside Rg_1,Ginsenoside Rb_1 and Ginsenoside Rd with different surface activity,the MWCO range of UF membranes can be divided into two zones mainly due to the retention rate difference among Notoginsenoside R_1,Ginsenoside Rg_1,Ginsenoside Rb_1 and Ginsenoside Rd.Zone 1,1000-10000;and Zone II,10000-100000.Thus,the new method would be helpful to improve the applicability of UF membrane in separation technology.
基金Supported by the Natural Science Foundation of Fujian Province of China （E0810018）
文摘An optimal medium （300 g·L^-1 initial glucose） comprising 6.3 mmol·L^-1 Mg2＋, 5.0 mmol·L^-1 Ca2＋, 15.0 g·L^-1 peptone and 21.5 g·L^-1 yeast extract was determined by uniform design to improve very high gravity （VHG） ethanol fermentation, showing over 30% increase in final ethanol （from 13.1% to 17.1%, by volume）, 29% decrease in fermentation time （from 84 to 60 h）, 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.
文摘Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (BKC) has an inhibitory effect on many bacteria but it has no significant effect on Pseudomonas aeruginosa. Cetrimide agar medium is recommended for the isolation and enumeration of Ps. aeruginosa in food and environmental samples. However, there are claims that for some food factories and in particular the bottled water industry, the selectivity of this medium is not sufficient. The aim of the current research is the creation of a more selective medium for Ps. aeruginosa with BKC. A total of 28 isolates were isolated with Cetrimide agar from raw water samples and identified using biochemical tests and commercial identification kits. All the bacteria were inoculated in Cetrimide agar plates containing 0 - 625 μg/mL BKC. The Petri dishes were incubated at 37°C and 42°C for 24 h. The results showed that 375 μg/mL BKC was sufficient to suppress Burk. pseudomallei at both incubation temperatures. Ps. fluorescens-35 could not grow at 42°C at any concentration, including the control, and was suppressed at 500 μg/mL BKC. All the Ps. aeruginosa isolates and control strain were grown at both incubation temperatures at 375 μg/mL BKC concentration. In conclusion, the analysis of Ps. aeruginosa showed that the growth of accompanying flora may be suppressed by adding 375-μg/mL BKC into Cetrimide agar and incubating at an elevated temperature of 42°C.
文摘目的探讨胰蛋白胨葡萄糖培养基(TGEA)法和营养琼脂法对内镜终末漂洗水的监测效果,以及比较试剂盒过滤集菌法和传统过滤集菌法对内镜消毒质量的监测效果。方法调查天津市24家医疗机构内镜中心基本信息,随机抽取终末漂洗水及内镜管腔冲洗水水样,分别采用两种方法检测细菌菌落数。结果 TGEA法对终末漂洗水监测所得检出率(96.7% vs 73.3%)、菌落数(中位数44 CFU/100 ml vs 8 CFU/100 ml)均高于营养琼脂法,差异有统计学意义(P <0.05),Bland-Altman分析显示两方法一致性较差;试剂盒过滤集菌法和传统过滤集菌法监测内镜消毒质量检出率(60.0%vs 56.7%)及菌落数(中位数2 CFU/件vs 1 CFU/件)相近,差异无统计学意义(P>0.05),Bland-Altman分析显示两方法一致性较好。结论被调查单位对终末漂洗水及内镜消毒质量的监测水平较低、采用检测方法规范性差。TGEA法对终末漂洗水检测更具敏感性、临床适应性强,试剂盒过滤集菌法操作简单、快捷、高效、准确,两种方法均适合内镜中心的日常监测。
