High cut-off membranes in patients requiring renal replacement therapy:a systematic review and meta-analysis

Background:Whether high cut-off(HCO)membranes are more effective than high-flux(HF)membranes in patients requiring renal replacement therapy(RRT)remains controversial.The aim of this systematic review was to investigate the efficacy of HCO membranes regarding the clearance of inflammation-related mediators,β2-microglobulin and urea;albumin loss;and all-cause mortality in patients requiring RRT.Methods:We searched all relevant studies on PubMed,Embase,Web of Science,the Cochrane Library,and China National Knowledge Infrastructure,with no language or publication year restrictions.Two reviewers independently selected studies and extracted data using a prespecified extraction instrument.Only randomized controlled trials(RCTs)were included.Summary estimates of standardized mean differences(SMDs)or weighted mean differences(WMDs)and risk ratios(RRs)were obtained by fixed-effects or random-effects models.Sensitivity analyses and subgroup analyses were performed to determine the source of heterogeneity.Results:Nineteen RCTs involving 710 participants were included in this systematic review.Compared with HF membranes,HCO membranes were more effective in reducing the plasma level of interleukin-6(IL-6)(SMD-0.25,95%confidence interval(CI)-0.48 to-0.01,P=0.04,I 2=63.8%);however,no difference was observed in the clearance of tumor necrosis factor-α(TNF-α)(SMD 0.03,95%CI-0.27 to 0.33,P=0.84,I 2=4.3%),IL-10(SMD 0.22,95%CI-0.12 to 0.55,P=0.21,I 2=0.0%),or urea(WMD-0.27,95%CI-2.77 to 2.23,P=0.83,I 2=19.6%).In addition,a more significant reduction ratio ofβ2-microglobulin(WMD 14.8,95%CI 3.78 to 25.82,P=0.01,I 2=88.3%)and a more obvious loss of albumin(WMD-0.25,95%CI-0.35 to-0.16,P<0.01,I 2=40.8%)could be observed with the treatment of HCO membranes.For all-cause mortality,there was no difference between the two groups(risk ratio[RR]1.10,95%CI 0.87 to 1.40,P=0.43,I 2=0.0%).Conclusions:Compared with HF membranes,HCO membranes might have additional benefits on the clearance of IL-6 andβ2-microglobulin but not on TNF-α,IL-10,and urea.Albumin loss is more serious with the treatment of HCO membranes.There was no difference in all-cause mortality between HCO and HF membranes.Further larger high-quality RCTs are needed to strengthen the effects of HCO membranes.

High-performance imidazole-containing polymers for applications in high temperature polymer electrolyte membrane fuel cells

This work focuses on the development of high temperature polymer electrolyte membranes(HT-PEMs)as key materials for HT-PEM fuel cells(HT-PEMFCs).Recognizing the challenges associated with the phosphoric acid(PA) doped polybenzimidazole(PBI) membranes,including the use of carcinogenic monomers and complex synthesis procedures,this study aims to develop more cost-effective,readily synthesized,and high-performance alternatives.A series of superacid-catalyzed polyhydroxyalkylation reactions have been carefully designed between p-terphenyl and aldehydes bearing imidazole moieties,resulting in a new class of HT-PEMs.It is found that the chemical structure of aldehyde-substituted N-heterocycles significantly impacts the polymerization reaction.Specifically,the use of 1-methyl-2-imidazole-formaldehyde and 1 H-imidazole-4-formaldehyde monomers leads to the formation of high-viscosity,rigid,and ether-free polymers,denoted as PTIm-a and PTIm-b.Membranes fabricated from these polymers,due to their pendent imidazole groups,exhibit an exceptional capacity for PA absorption.Notably,PTIm-a,carrying methylimidazole moieties,demonstrates a superior chemical stability by maintaining morphology and structural stability during 350 h of Fenton testing.After being immersed in 75 wt% PA at 40℃,the PTIm-a membrane reaches a PA content of 152%,maintains a good tensile strength of 13.6 MPa,and exhibits a moderate conductivity of 50.2 mS cm^(-1) at 180℃.Under H_(2)/O_(2) operational conditions,a single cell based on the PTIm-a membrane attains a peak power density of 732 mW cm^(-2) at 180℃ without backpressure.Furthermore,the membrane demonstrates stable cycle stability over 173 h within 18 days at a current density of 200 mA cm^(-2),indicating its potential for practical application in HT-PEMFCs.This work highlights innovative strategies for the synthesis of advanced HT-PEMs,offering significant improvements in membrane properties and fuel cell performance,thus expanding the horizons of HT-PEMFC technology.

Internal limiting membrane peeling combined with silicone oil or air tamponade for highly myopic foveoschisis

AIM:To compare the efficacy of pars plana vitrectomy(PPV)combined with internal limiting membrane(ILM)and silicone oil or sterile air tamponade for the treatment of myopic foveoschisis(MF)in highly myopic eyes.METHODS:This retrospective study included 48 myopic eyes of 40 patients with MF and axial lengths(ALs)ranging from 26-32 mm treated between January 2020 and January 2022.All patients were underwent PPV combined with ILM peeling followed by sterile air or silicone oil tamponade and followed up at least 12mo.Based on the features on spectral-domain optical coherence tomography(SD-OCT),the eyes were divided into the MF-only group(Group A,n=15 eyes),MF with central foveal detachment group(Group B,n=20 eyes),and MF with lamellar macular hole group(Group C,n=13 eyes).According to AL,eyes were further divided into three groups:Group D(26.01-28.00 mm,n=12 eyes),Group E(28.01-30.00 mm,n=26 eyes),and Group F(30.01-32.00 mm,n=10 eyes).The best-corrected visual acuity(BCVA),central foveal thickness(CFT),and complications were recorded.RESULTS:The patients included 16 males and 24 females with the mean age of 56±9.82y.The BCVA and CFT improved in all groups after surgery(P<0.01),while there was no significant difference of the CFT in Group A,B,and C postoperatively(P>0.05).The intergroup differences of BCVA and CFT postoperatively were statistically significant in Group D,E,and F.Twenty eyes were injected with sterile air,and 28 eyes were injected with silicone oil for tamponade based on the AL.However,there was no statistically significant difference among Groups D,E,and F in terms of the results of sterile air or silicone oil tamponade.The mean recovery time was 5.9mo for MF patients subjected to silicone oil tamponade and 7.7mo for patients subjected to sterile air tamponade,and the difference was not statistically significant.CONCLUSION:PPV and ILM peeling combined with silicone oil or sterile air tamponade can achieve good results for MF in highly myopic eyes with ALs≤32 mm.

Intermolecular Acid-Base-Pairs Containing Poly(p-Terphenyl-co-lsatin Piperidinium)for High Temperature Proton Exchange Membrane Fuel Cells

How to optimize and regulate the distribution of phosphoric acid in matrix,and pursuing the improved electrochemical performance and service lifetime of high temperature proton exchange membrane(HT-PEMs)fuel cell are significant challenges.Herein,bifunctional poly(p-terphenyl-co-isatin piperidinium)copolymer with tethered phosphonic acid(t-PA)and intrinsic tertiary amine base groups are firstly prepared and investigated as HT-PEMs.The distinctive architecture of the copolymer provides a well-designed platform for rapid proton transport.Protons not only transports through the hydrogen bond network formed by the adsorbed free phosphoric acid(f-PA)anchored by the tertiary amine base groups,but also rely upon the proton channel constructed by the ionic cluster formed by the t-PA aggregation.Thorough the design of the structure,the bifunctional copolymers with lower PA uptake level(<100%)display prominent proton conductivities and peak power densities(99 mS cm^(-1),812 mW cm^(-2)at 160℃),along with lower PA leaching and higher voltage stability,which is a top leading result in disclosed literature.The results demonstrate that the design of intermolecular acid-base-pairs can improve the proton conductivity without sacrificing the intrinsic chemical stability or mechanical property of the thin membrane,realizing win-win demands between the mechanical robustness and electrochemical properties of HT-PEMs.

Gradient nanoporous phenolics as substrates for high-flux nanofiltration membranes by layer-by-layer assembly of polyelectrolytes

Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m-2?h-1?MPa-1, which is ~2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.

Enhanced air filtration performance under high-humidity condition through electrospun membranes with optimized structure

The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%.The developed hydrophobic filters possess comparable separation performance with the hydrophilic one,but greatly enhanced stability.After the introduction of beadon-string structure,the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity.Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons.

PREPARATION OF HIGH DENSITY POLYETHYLENE/POLYETHYLENE-BLOCK-POLY(ETHYLENE GLYCOL)COPOLYMER BLEND POROUS MEMBRANES VIA THERMALLY INDUCED PHASE SEPARATION PROCESS AND THEIR PROPERTIES

High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.

Sulfonated polybenzimidazole/amine functionalized titanium dioxide(s PBI/AFT) composite electrolyte membranes for high temperature proton exchange membrane fuel cells usage

The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel cells(HT-PEMFCs),unlike the prior low temperature AFT endeavors.The high temperature compatibility was actualized because of the filling of free volumes in the rigid aromatic matrix of the composite with AFT nanoparticles which inhibited segmental motions of the chains and improved its thermal stability.Besides,amine functionalization of TiO2 enhanced their dispersion character in the sPBI matrix and shortened the interparticle separation gap which finally improved the proton transfer after establishing interconnected pathways and breeding more phosphoric acid(PA) doping.In addition,the appeared assembled clusters of AFT flourished a superior mechanical stability.Thus,the optimized sPBI/AFT(10 wt%) showed 65.3 MPa tensile strength;0.084 S·cm^-1 proton conductivity(at 160℃;in anhydrous conditions),28.6% water uptake and PA doping level of 23 mol per sPBI repeat unit.The maximum power density peak for sPBI/AFT-10 met the figure of0.42 W·cm^-2 at 160℃(in dry conditions) under atmospheric pressure with 1.5 and 2.5 stoichiometric flow rates of H2/air.These results affirmed the probable fitting of sPBI/AFT composite for HT-PEMFC applications.

A convenient method for the determination of molecular weight cut-off of ultrafiltration membranes

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.

High-yield Cultivation Techniques of Drip Irrigation under Ground Membrane for Cotton

Yuepuhu County in Xinjiang has a long history of cotton planting and is a national high-quality cotton base county.In 2002,it was appraised by the Ministry of Agriculture as the"Hometown of High-yield Cotton Production in China",with an annual cotton planting area of about 43000 ha.Traditional cotton planting has disadvantages such as waste of water resources,low water use efficiency,easy breeding of diseases and insect pests,and unfavorable ground temperature recovery at the seedling stage.In order to solve the low water use efficiency in cotton planting in Yuepuhu County,reduce the occurrence of diseases and insect pests,promote sustainable cotton production,and improve the economic benefits and local ecological benefits of cotton planting,Yuepuhu County promoted the application of the resource-saving technology drip irrigation under ground membrane cotton comprehensive cultivation technology mainly promoted by the Ministry of Agriculture.This paper mainly discusses the disadvantages of traditional cotton planting,the main technical content of drip irrigation under ground membrane technology,the problems found in the practice process and the solutions,so as make cotton growers in Yuepuhu County better understand the planting technology under plastic film,and to better promote the development of cotton industry in Yuepuhu County and the surrounding regions.

Application of High-pressure Flat Membranes in Coal Chemical Wastewater Treatment

In the process of using high-pressure flat membranes to treat coal chemical wastewater,the effects of high-pressure flat membranes on the concentration of salt ions and the removal of pollutants were studied under the conditions of different concentrations of influent TDS,COD and silicon dioxide.The results showed that when the concentration of influent TDS was 35 000-55 000 mg/L,the economic benefit of high-pressure flat membrane operation was the best,and the concentration ratio of high-pressure flat membranes was stable,varying from 3.3 to 3.6.As the concentration of influent organic matter ranged from 100 to 1 800 mg/L,the removal rate of organic matter ranged from 60% to 79%.In addition,the retention rate of high-pressure flat membranes to silicon dioxide was more than 90%.

THE ASYMPTOTIC PROPERTIES OF HIGH FREQUENCIES FOR BARS,BEAMS AND MEMBRANES

In this paper, a uniform analysis of the asymptotic properties of high frequencies of non-uniform bars, beams and circular membranes is given by using perturbation method, and the ease of discontinuous physical parameters is also discussed.

High matrix metalloproteinase-9 expression induces angiogenesis and basement membrane degradation in stroke-prone spontaneously hypertensive rats after cerebral infarction

Basement membrane degradation and blood-brain barrier damage appear after cerebral infarc- tion, severely impacting neuronal and brain functioning; however, the underlying pathogenetic mechanisms remain poorly understood. In this study, we induced cerebral infarction in stroke- prone spontaneously hypertensive rats by intragastric administration of high-sodium water （1.3% NaC1） for 7 consecutive weeks. Immunohistochemical and immunofluorescence assays demonstrated that, compared with the non-infarcted contralateral hemisphere, stroke-prone spontaneously hypertensive rats on normal sodium intake and Wistar-Kyoto rats, matrix metalloproteinase-9 expression, the number of blood vessels with discontinuous collagen IV expression and microvessel density were significantly higher, and the number of continuous collagen IV-positive blood vessels was lower in the infarct border zones of stroke-prone sponta- neously hypertensive rats given high-sodium water. Linear correlation analysis showed matrix metalloproteinase-9 expression was positively correlated with the number of discontinuously collagen IV-labeled blood vessels and microvessel density in cerebral infarcts of stroke-prone spontaneously hypertensive rats. These results suggest that matrix metalloproteinase-9 upregula- tion is associated with increased regional angiogenesis and degradation of collagen IV, the major component of the basal lamina, in stroke-prone spontaneously hypertensive rats with high-sodi- um water-induced focal cerebral infarction.

Preparation of High Concentration Polyaluminum Chloride with High Al_c Content by Membrane Distillation

A direct contact membrane distillation（DCMD）process was applied to prepare high concentration polyaluminum chloride（PACl）with high Alc content.The changes in total Al concentration（AlT）and Al species distribution were investigated.The results showed that AlT increased but the flux decreased with operating time during the DCMD process.The Alc content increased from 65%to 81%while the Alb content decreased from 34% to 18%,and the Ala content was almost 1%in the process.2.1 mol·L 1PACl with 81%Alc was successfully prepared by DCMD method.Thus the DCMD is an effective method for preparing high concentration PACl with high Alc content.

Macular Bruch's membrane defects and other myopic lesions in high myopia

AIM: To compare the ocular fundus features of highly myopic eyes with and without macular Bruch’s membrane(BM) defects and investigate the associations between macular BM defects and other myopic lesions.METHODS: This retrospective, observational case series included 262 eyes(139 patients) with high myopia(HM) refractive error ≥-6.0 diopters(D) or axial length ≥26.5 mm from March 2019 to December 2019.The patients underwent a comprehensive ophthalmic examination, including sweptsource optical coherence tomography(SS-OCT).The features of macular BM defects and other ocular fundus lesions were examined in OCT images.RESULTS: Totally 51 eyes(19.5%) were detected with macular BM defects, which were characterized by a lack of BM, retinal pigment epithelium(RPE), and an almost complete loss of photoreceptors or choriocapillaris.Eyes with macular BM defects had worse best-corrected visual acuity(BCVA) than those without(P<0.001).Dome-shaped macula(DSM, P=0.042), retinal cysts(P=0.006), choroidal neovascularization(CNV, P<0.001), choroidal defects and abnormality(P=0.003), scleral defects(P=0.015), scleral deformation(P=0.005), posterior staphyloma(P=0.011), and perforating vessels(P<0.001) occurred more frequently in eyes with macular BM defects.In multivariate analysis, the presence of macular BM defects remained the significant association with presence of DSM(P=0.013), scleral defects(P=0.015), posterior staphyloma(P=0.001), perforating vessels(P<0.001) and CNV(P=0.004).CONCLUSION: Macular BM defects has a prevalence of approximately 20% in HM and it has tight association with other myopic fundus lesions.BM might be crucial in the pathogenesis of myopic fundus lesions due to its biomechanical function.A comprehensive understanding of BM’s role is useful for further researches about myopic lesions.

Amniotic membrane for covering high myopic macular hole associated with retinal detachment following failed primary surgery

AIM:To evaluate the therapeutic effect of amniotic membrane(AM)for covering high myopic macular hole associated with retinal detachment following failed primary surgery.METHODS:Seventeen eyes of 17 patients whose axial length was more than 29 mm suffered from macular hole(MH)or MH associated with retinal detachment(RD),and had previously surgery of pars plana vitrectomy(PPV)with internal limiting membrane(ILM)peeling and silicone oil(SO)tamponade.Half a year after the surgery,optical coherence tomography(OCT)showed that MH did not heal in all 17 eyes and RD was still maintained in 13 eyes of these 17 eyes.We performed SO removal combined with AM covering on macular area and C3 F8 tamponade,and phacoemulsification combined with intraocular lens implantation simultaneously cataract eyes.We followed up these patients for one year.RESULTS:In all 17 eyes,SO was removed successfully,MHs were healed and RDs were reattached.One eye(5.89%,1/17)had AM shifted half a month after surgery and underwent a second surgery to adjust the position of the AM and supplement C3 F8.After surgery,the visual acuity(VA)improved in 15 eyes(88.24%,15/17),no change in two eyes(11.76%,2/17).No serious complications occurred in all eyes.CONCLUSION:AM covering is helpful to rescue the previous failure surgery of high myopic MH.

Influence of osmotic distillation on membrane absorption for the treatment of high strength ammonia wastewater

Osmotic distillation(OD) was found to be a coupled process in membrane absorption(MA) for the treatment of high strength ammonia wastewater. As a result, ammonia could not be concentrated in absorption solution(AS) as expected. The inhibition of the coupled OD in MA process was investigated as well as various factors affecting the inhibition. The results indicated that the coupled OD can be effectively inhibited by heating concentrated solution and cooling dilute solution. It was also found that experimental minimum inhibition temperature difference(MITD) between concentrated and dilute solutions was different when using polyvinylidene fluoride(PVDF) and polypropylene(PP) membranes respectively, which could be ascribed to material properties, such as OD and membrane distillation(MD) coefficients of the membranes. Experimental MITDs were found to be higher than theoretical MITDs which were calculated using a simplified method.

Engineer Nanoscale Defects into Selective Channels:MOF-Enhanced Li^(+) Separation by Porous Layered Double Hydroxide Membrane

Two-dimensional(2D)membrane-based ion separation technology has been increasingly explored to address the problem of lithium resource shortage,yet it remains a sound challenge to design 2D membranes of high selectivity and permeability for ion separation applications.Zeolitic imidazolate framework functionalized modified layered double hydroxide(ZIF-8@MLDH)composite membranes with high lithium-ion(Li^(+)) permeability and excellent operational stability were obtained in this work by in situ depositing functional ZIF-8 nanoparticles into the nanopores acting as framework defects in MLDH membranes.The defect-rich framework amplified the permeability of Li^(+),and the site-selective growth of ZIF-8 in the framework defects bettered its selectivity.Specifically speaking,the ZIF-8@MLDH membranes featured a high permeation rate of Li^(+) up to 1.73 mol m^(−2) h^(−1) and a desirable selectiv-ity of Li^(+)/Mg^(2+) up to 31.9.Simulations supported that the simultaneously enhanced selectivity and permeability of Li+are attributed to changes in the type of mass transfer channels and the difference in the dehydration capacity of hydrated metal cations when they pass through nanochannels of ZIF-8.This study will inspire the ongoing research of high-performance 2D membranes through the engineering of defects.

Nafion/Silicon Oxide Composite Membrane for High Temperature Proton Exchange Membrane Fuel Cell

Nafion/Silicon oxide composite membranes were produced via in situ sol-gel reaction of tetraethylorthosilicate （TEOS） in Nafion membranes. The physicochemical properties of the membranes were studied by FT-IR,TG-DSC and tensile strength. The results show that the silicon oxide is compatible with the Nation membrane and the thermo stability of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. Furthermore, the tensile strength of Nation/Silicon oxide composite membrane is similar to that of the Nation membrane. The proton conductivity of Nation/Silicon oxide composite membrane is higher than that of Nation membrane. When the Nation/Silicon oxide composite membrane was employed as an electrolyte in H2/O2 PEMFC, a higher current density value （1 000 mA/cm^2 at 0.38 V） than that of the Nafion1135 membrane （100 mA/cm^2 at 0.04 V） was obtained at 110 ℃.