Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier materials.However,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane efficiencies.In this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing conditions.The results were consistent with numerical models under two scenarios considering different inflow/outflow positions.The proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the bound-aries.The calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent concentrations.The retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass approach.Finally,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

Monitoring of polymeric membrane fouling in hollow fiber module using ultrasonic nondestructive testing

This study describes the development of novel protocols extending the real-time ultrasonic reflectometry(UTDR) for the detection of membrane fouling in hollow fiber module during ultrafiltration(UF) of oily water treatment. A specially designed acoustic sensor with a frequency of 2.5 MHz was used. The hollow fiber membranes used were polysulphone(PSf) UF membranes with MWCO 40 kDa. The wastewaters with three different oily concentrations of 100, 500 and 1 000 mg/L were investigated. Diesel oil was utilized as the primary foulant. The results show that the permeate flux declines with operation time and its value becomes lower with the increase of the oily concentration in wastewater. It is found that ultrasonic measurement can detect the fouling and cleaning processes. A new signal analysis protocol-ultrasonic reflected energy was developed. Ultrasonic reflected energy obtained indicates the deposition of oily layer as a function of operation time and its removal after cleaning. The overall flux decline is reasonably correlated with the changes in ultrasonic reflected energy. This research provides the evidence that the ultrasonic reflectometry technique is capable of monitoring membrane fouling and cleaning in hollow fiber modules.

Cryodamage to plasma membrane integrity in head and tail regions of human sperm

Aim: To investigate the effect of cryopreservation on the plasma membrane integrity in the head and tail regions ofindividual sperm, and the relationship between intact cryopreserved sperm and its motility and zona-free hamster oocytepenetration rate. Methods: The eosin Y exclusion and the hypoosmotic swelling tests were combined to form a sin-gle test (HOS-EY test) to identify the spermatozoa with four types of membrane integrity. Results: After cryop-reservation, there was a marked decline in the percentage of spermatozoa with Type Ⅳ membrane integrity (head mem-brane intact/tail membrane intact), and a significant increase in those with Type Ⅰ (head membrane damaged/tail mem-brane damaged) and Type Ⅲ (head membrane damaged/tail membrane intact) membrane integrity (n = 50, P <0.01). The value of Type Ⅲ integrity had a wide range of variability, whereas Type Ⅱ (head membrane intact/tailmembrane damaged) was uncommon after thawing. A high correlation was observed between the percentage of Type Ⅳintegrity and sperm motility ( n = 50, r = 0.74, P < 0.01 ). However, the values of Type Ⅳ integrity were usuallylower than those of post-thaw motility in most cryopreserved samples. The value of Type Ⅳ integrity did not correlatewith the sperm penetration rate ( n = 25, r = 0.22, P > 0.05). Conclusion: (1) The HOS-EY test has the advan-tage of showing four patterns of membrane integrity in individual spermatozoon; (2) Cryopreservation causes a signifi-cant membrane rupture in the head and tail regions of spermatozoa; Type Ⅲ is the main transitional state of membranecryodamage; (3) Cryodamage to head and tail membrane may occur independently; the presence of an intact tail mem-brane does not necessarily indicate the intacmess of head membrane. (4) Intact membranes are closely related to post-thaw motility, but do not reflect the fertilizing potential.

Experimental Study and Model Analysis of the Performance of IPMC Membranes with Various Thickness

Ionic Polymer-Metal Composite （IPMC） is a new electro-active polymer, which has the advantages of light weight, flexibility, and large stroke with low driving voltage. Because of these features, IPMC can be applied to bionic robotic actuators, artificial muscles, as well as dynamic sensors. However, IPMC has the major drawback of low generative blocking force. In this paper, in order to enhance the blocking force, the Nation membranes with thickness of 0.22 mm, 0.32 mm, 0.42 mm, 0.64 mm and 0.8 mm were prepared by casting from liquid solution. By employing these Nation membranes, IPMCs with varying thickness were fabricated by electroless plating. The elastic modulus of the casted Nation membranes were obtained by a nano-indenter, and the current, the displacement and the blocking force were respectively measured by the apparatus for actuation test. Finally, the effects of the thickness on the performance of IPMC were analyzed with an electromechanical model. Experimental study and theory analysis indicate that as the thickness increases, the elastic modulus of Nation membrane and the blocking force of IPMC increase, however, the current and the displacement decrease.

Feasibility and simulation model of a pilot scale membrane bioreactor for wastewater treatment and reuse from Chinese traditional medicine

The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time （HRT） of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows： HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/（m3.d）, the range of MLSS was between 7543-13694 mg/L.

Influence of enterococci on human sperm membrane in vitro

Aim： To study the influence of enterococci on human sperm membrane in vitro. Methods： Ejaculated human sperm were artificially infected with β-hemolytic or non-β-hemolytic enterococci at the bacteria： sperm ratio of 50：1 at 37℃. Sperm membrane integrity was examined after incubation for 1, 3 and 5 h by hypoosmotic swelling （HOS） test and electron microscopy. Results： Sperm infected with β-hemolytic enterococci had lower HOS scores compared with non-β-hemolytic strains or uninfected control （P 〈 0.01）. The HOS test scores of sperm infected with β-hemolytic enterococci increased in the presence of phosphatidylcholine, an inhibitor of hemolysin. Non-β-hemolytic strains showed no significant difference in swelling rate, compared with the control group （P 〉 0.05）. It was shown by electron microscopy that β-hemolytic enterococci caused significant rupture of human sperm membrane. Conclusion： β-hemolytic enterococci caused human sperm membrane injury, and might be mediated by the hemolysin of enterococci.

Preparation and Optimization of Porous Membrane Electrodes via Gradient Coating in Hydrogen Fuel Cell

Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of the Pt/C catalysts with different Pt loading,and by changing the Nafion content,hot pressing temperature and hot pressing pressure,the catalyst coated membrane(CCM)spraying process was optimized.Moreover,the three-dimensional structure model of the single battery membrane electrode was studied quantitatively,and the porous membrane electrode with gradient distribution was fabricated under optimized processing conditions,with excellent electrical performance.

Controlling Pore Size and its Distribution of γ-Al_2O_3 Nanofiltration Membranes

The preparation process of γ-A12O3 nanofiltration membranes were studied by N2 absorption and desorption test and retention rate vs thickness gradient curve method. It was found that template and thermal treatment were key factors for controlling pore size and its distribution. Under the optimized experimental conditions, the BJH (Barret-Joyner-Halenda) desorption average pore diameter, BJH desorption cumulative volume of pores and BET (Brunauer-Emmett-Teller) surface area of obtained membranes were about 3.9 nm, 0.33 cm3/g and 245 m2/g respectively, the pore size distribution was very narrow. Pore size decreased with the increasing of thickness and no evident change after the dense top layer was formed. The optimum thickness can be controlled by retention rate vs thickness gradient curve method.

Synthesis, Characterization and Biological Activities of Novel Water-soluble Metalloporphyrins

The synthesis, characterization, and biological activities of a series of metal porphyrins were described. The complexes 3a similar to 3e were prepared from the reaction of compound 2 with M(OAc)(2) in CHCl3, and the treatment of 3a similar to 3f with pyridine gave corresponding complexes 4a similar to 4f. These new compounds were identified by absorption spectroscopies, H-1 NMR and elemental analysis. The results of biological activity,testing revealed that 4a and 4c had stronger inhibiting action for Escherichia coli (CCTCC AB91115).

Graphene/carbon structured catalyst layer to enhance the performance and durability of the high-temperature proton exchange membrane fuel cells

In this study,nitrogen doped electrochemically exfoliated reduced graphene oxide and carbon black supported platinum(Pt/Nr EGO_(2)-CB_(3))has been prepared to enhance the performance and durability of hightemperature PEMFCs with lower Pt loading.On the one hand,Pt/Nr EGO_(2)-CB_(3)with the strong interaction between the Pt and nitrogen(N)prevent agglomeration of Pt particles and Pt particles is 5.46±1.46 nm,which is smaller than that of 6.78±1.34 nm in Pt/C.Meanwhile,ECSA of Pt/Nr EGO_(2)-CB_(3)decrease 13.65%after AST,which is much lower than that of 97.99%in Pt/C.On the other hand,the Nr EGO flakes in MEAac act as a barrier to mitigate phosphoric acid redistribution,which improves the formation of triple-phase boundaries(TPBs)and gives stable operation of the MEAacwith a lower decay rate of 0.02 mV h^(-1)within100 h.After steady-state operation,the maximum power density of Pt/Nr EGO_(2)-CB_(3)(0.411 W cm^(-2))is three times higher than that of conventional Pt/C(0.134 W cm^(-2))in high-temperature PEMFCs.After AST,the mass transfer resistance of Pt/Nr EGO_(2)-CB_(3)electrode(0.560Ωcm^(2))is lower than that in Pt/C(0.728Ωcm^(2)).

Ex situ aging effect on sulfonated poly(ether ether ketone) membrane:Hydration-dehydration cycling and hydrothermal treatment

Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation provides incremental proton conductivity to the membranes, whereas mechanical degradation drastically reduces device stability. On this basis, we describe here the effects of two different ex situ aging processes on sulfonated poly(ether ether ketone) membranes: hydrationdehydration cycling and prolonged hydrothermal treatment. Both aged membranes exhibited enhanced phase separation under the hydrated conditions, as characterized by small angle X-ray scattering.However, when the aged membranes were dried again, the nanostructure of the membranes aged via the hydration-dehydration cycling was recoverable, whereas that of the membranes aged via prolonged hydrothermal treatment was irreversible. Furthermore, the two differently aged membranes showed clear differences in thermal, mechanical, and electrochemical properties. Finally, we implemented both aged membranes in fuel cell application. The sample aged via hydration-dehydration cycling maintained its improved cell performance, whereas the sample aged via hydrothermal treatment showed drastically reduced cell performance after durability test for 50 h.

Peritoneal Membrane Transport Characteristics in Uni-PET with Preceding Icodextrin Dwell as Compared to Classic PET with Preceding Glucose Dwell: A Prospective Study

Background: In subjects on CAPD who use icodextrin for long night dwell, it has been recommended that nocturnal exchange be replaced by dextrose dwell whenever PET is to be performed as preceding exchange with icodextrin temporarily increases peritoneal membrane permeability and therefore, gives high D/PCr and low D/D0 glucose values. Whether this temporary change is also seen with use of Uni-PET (which involves one hour dwell of 1.5% dextrose followed by 4-hour dwell of 4.25% dextrose) is not known. Methods: In this self, controlled study, subjects on CAPD, who were using icodextrin for long nocturnal dwell for at least 3 months, were screened for enrolment. Pregnancy or lactation, history of any PD related infectious complication in the past one month, present or past malignancy, and poor functional status were exclusion criteria. Enrolled subjects underwent classic PET with preceding 2.5% dextrose long nocturnal dwell on day 1 followed by Uni-PET with preceding 7.5% icodextrin long nocturnal dwell on day 2. Difference in D/PCr and D/D0 glucose between the two PETs was primary objectives. The study was approved by Institute Ethics Committee. Results: 15 out of 26 screened subjects were enrolled over a period of 18 months (July 2015-December 2016). The mean (±SD) age of study population was 60.8±9.1 years. Majority were males and diabetes was the most common cause of CKD. Mean D/PCr were 0.68 ± 0.11 and 0.64 ± 0.08 in classic PET and Uni-PET, respectively. The difference between the two values was not significant [mean difference between D/PCr (classic PET-Uni-PET): 0.040 ± 0.86;95% CI (-0.007 to 0.088);p = 0.09]. Similarly, D/D0 glucose between classic PET and Uni-PET was also similar [mean difference between D/D0 glucose (classic PET-Uni-PET): -0.02 ± 0.09;95% CI (-0.06 to 0.03);p = 0.448]. Conclusion: Peritoneal membrane small solute transport characteristics in Uni-PET with preceding icodextrin dwell are similar to classic PET with preceding glucose dwell. If Uni-PET is used, it may not be necessary to replace preceding nocturnal exchange of icodextrin with that of dextrose as is currently advised.

Treatment of Chinese traditional medicine wastewater in a submerged membrane bioreactor

A pilot scale test was conducted in a submerged membrane bioreactor SMBR with capacity of 10. 0 m^3/d for 120 days to treat high-strength Chinese traditional medicine wastewater. Performance of the SMBR was investigated with a sludge retention time （ TSR ） of 50 days, a hydraulic retention time （ THR ） of 8.0 h, membrane flux of 8. 0 IV（ m^2 · h） and dissolved oxygen （DO） concentration of 2. 0 - 3. 0 mg/L, respectively. It was observed that the SMBR had high capacity of COD and suspended solid （SS） removal. The influent COD concentration was fluctuated between I 000 and 5 000 mg/L, while the averaged effluent COl） concentration was only 44. 6 mg/L. The influent SS concentration was fluctuated between 1 000 and 1 600 mg/L, while little effluent SS was detected. It was found that the COD remove rate increased with mixed liquor suspended solids （MLSS） and organic loading rate （ROL）. In order to obtain good-quality effluent, the operational conditions of the SMBR were suggested as follows： the temperature was controlled above 10 ℃, MLSS about 7000 mg/L, R,L under 24. 76 kg/（ m^3 · d）, low vacuum value and constant water flux.

Dip-coating of SiO2 onto ZnO-SiC Composite Membrane

SiC composite membrane was fabricated by mixing with SiC and ZnO powder. This mixture was pressed and sintered at 1,300 ℃ under air condition. This sintered ZnO-SiC membrane was dip-coated by silica sol and followed by heat-treatment. This membrane was characterized by XRD （X-ray diffraction）, FE-SEM （field emission scanning electron microscopy） and BET （Brunauer-Emmett-Teller） instruments. Hydrogen permeation test was conducted at 0.1 MPa pressure and also variation of temperatures. The obtained value of heat-treated membrane after dip-coating at 298 K was obtained as 1.61 × 10-6 mol/（m2·s·Pa）.

血栓弹力图与常规凝血试验应用于ECMO治疗中止凝血管理的对比研究

目的探讨血栓弹力图(thromboelastography,TEG)与常规凝血试验各参数的相关性和一致性,评价2种方法在体外膜肺氧合(extracorporeal membrane oxygenation,ECMO)支持治疗患者肝素抗凝监测及凝血功能监测中的应用价值。方法选取2021年10月—2022年12月就诊于广西壮族自治区人民医院重症医学科的138例ECMO支持治疗的患者,对同步检测的共317对普通TEG、肝素酶纠正的血栓弹力图(heparinase-modified thromboelastography,hmTEG)参数与活化部分凝血活酶时间(APTT)、纤维蛋白原(Fib)、血小板计数(Plt)等指标进行相关性及一致性分析,并对ECMO建立时和ECMO运行24 h后的指标进行比较。结果hmTEG的凝血反应时间(R)与APTT的相关系数(r=0.441,P<0.05)低于普通TEG R值与APTT的相关系数(r=0.547,P<0.05);普通TEG的凝固角(α-Angle)、凝血形成时间(K)与Fib无相关关系(P>0.05),而hmTEG的α-Angle、K与Fib的相关系数分别为0.359(P<0.05)、-0.343(P<0.05);hmTEG的最大振幅(MA)与Plt的相关性为0.456(P<0.05),远低于其与Fib的相关性(r=0.715,P<0.05)。APTT和hmTEG对ECMO支持治疗患者普通肝素抗凝效果的判断具有中度的一致性(P<0.05)。ECMO上机24 h后Plt明显低于ECMO建立时(P<0.05),而Fib、APTT及hmTEG各参数等指标在两者间比较差异均无统计学意义(P>0.05)。结论hmTEG可以更好地反映ECMO支持治疗患者真实的凝血因子功能水平,使用hmTEG和APTT评估ECMO支持治疗患者肝素是否超量的结果可以相互参考,且hmTEG具有独特的优势。常规凝血试验和TEG检测不能相互替代,联合应用利于实现更好地抗凝和凝血管理。

矩形平面投影气膜结构风振响应特性及风振系数研究

近年来,矩形平面投影气膜结构被广泛应用于大跨度气膜煤仓等设施中,但是规范中尚无该类结构的风振系数。本文通过风洞测压试验,测量了典型矢跨比矩形平面投影气膜结构的风荷载;运用非线性动力时程分析法分析了结构的风振响应。研究了风速、风向、跨度、矢跨比和内压等参数对结构变形和响应极值的影响。结果表明:结构呈现迎风面及背风面凹陷、顶部和两侧向外凸的平均变形特征;极值响应的分布受结构参数和风向角的影响;响应的大小与跨度和矢跨比呈正相关;增大内压在一定程度上可以提高结构的抗风性,内压调控区间建议为400~500Pa;给出了可供抗风设计参考的位移风振系数及应力风振系数。

胶囊形气膜结构风致气弹响应及风振系数研究

针对1/3矢跨比胶囊形气膜结构进行了气弹模型风洞试验,研究了结构的风致气弹响应变化规律,并给出了可供设计参考的风振系数。研究发现:结构平均变形呈迎风面凹陷,顶部隆起,横风向向外凸出的趋势,且这种变形趋势随着内压减小和风速增大越来越明显。0°风向角时的平均变形和振幅大于45°风向角时的平均变形和振幅大于90°风向角时的平均变形和振幅,结构合位移均值的极值出现在迎风面与顶面中心点;0°和45°风向角下,顶点竖向振幅>顺风向振幅>横风向振幅,结构以1阶模态振动为主;90°风向角下,顶点横风向振幅大于其他两个方向,结构以1阶和2阶模态叠加振动为主。各工况下结构的内压均有不同程度的减小。最后给出了考虑流固耦合效应的响应风振系数。

抗生素类药品无菌检查方法研究进展

无菌检查法是无菌药品检查的法定检验方法,其中薄膜过滤法因易操作、风险低和准确度高等优点比直接接种法应用更广泛。无菌药品剂型种类繁多,其中抗生素类药品因品种结构多变、抑菌性强和抗菌谱广等因素,一直以来是建立无菌检查方法的难点。本文就薄膜过滤法中的溶解、过滤、冲洗和培养等4个关键步骤展开讨论,通过对已建立的13类47个品种共61个抗生素药品无菌检查方法的综述,探讨建立无菌检查方法的基本策略,并对无菌检查方法和结果的局限性进行讨论,以期为建立抗生素类无菌药品无菌检查方法及正确认识无菌检查结果提供思路和参考。

高温质子交换膜燃料电池动态性能测试教学实验设计

该文结合科研热点,设计了具有创新性和研究性的“高温质子交换膜燃料电池动态性能测试实验”。实验研究了阳极流动和死端模式下高温质子交换膜燃料电池在阶跃电流条件下的动态响应。从实验理论基础、实验平台搭建、性能测试方法及内容、实验结果探讨分析等方面,展示了科学研究的全过程。该实验旨在培养和提升学生的实验素养、科研能力、创新能力和实践能力。

基线腹膜转运特性对CAPD患者腹膜蛋白丢失、生存率及腹膜炎发生率的影响

目的:观察基线腹膜转运特性对持续不卧床腹膜透析(CAPD)患者腹膜蛋白丢失、腹膜炎发生率及生存率的影响。方法:回顾性分析2014年01月—2021年01月在我院行腹膜透析手术并规律CAPD治疗≥1年的91例患者作为研究对象,根据术后首次的腹膜平衡试验(PET)结果,将患者分为4组:高转运组(H)、高平均转运组(HA)、低平均转运组(LA)及低转运组(L),比较各组腹膜蛋白清除率(PrC)及腹膜炎发生率,分析终末期肾脏病(ESRD)不同原发病与其基线腹膜转运特性之间的关系。Kaplan-Meier生存曲线比较HT组(H和HA)和LT组(LA和L)患者的生存情况。结果:PrC水平在H、HA、LA及L四组间存在显著差异,H组的PrC水平显著高于HA、LA及L组,而其血清白蛋白水平显著低于其余三组(P<0.05)。不同ESRD原发病的患者,其基线腹膜转运特性也存在差异,糖尿病肾病患者的基线腹膜转运特性多为HA及H,而慢性肾小球肾炎患者的基线腹膜转运特性多为LA及HA。腹膜炎发生率及生存率在HT组和LT组差异无统计学意义(P>0.05)。结论:ESRD原发病不同可影响其基线腹膜转运特性的分布,不同基线腹膜转运特性PD患者间PrC水平存在显著差异,腹膜高转运特性的患者多伴有高的PrC水平和低的血白蛋白水平,而腹膜转运特性对CAPD患者的腹膜炎发生率及生存率无显著影响。