Membrane Structure Research Articles

Antibacterial activity and biosynthetic potential of Streptomyces sp. PBR19, isolated from forest rhizosphere soil of Assam.

An Actinomycetia isolate, designated as PBR19, was derived from the rhizosphere soil of Pobitora Wildlife Sanctuary (PWS), Assam, India. The isolate, identified as Streptomyces sp., shares a sequence similarity of 93.96% with its nearest type strain, Streptomyces atrovirens. This finding indicates the potential classification of PBR19 as a new taxon within the Actinomycetota phylum. PBR19 displayed notable antibacterial action against some ESKAPE pathogens. The ethyl acetate extract of PBR19 (EtAc-PBR19) showed the lowest minimum inhibitory concentration (MIC) of ≥ 0.195µg/mL against Acinetobacter baumannii ATCC BAA-1705. A lower MIC indicates higher potency against the tested pathogen. Scanning electron microscope (SEM) findings revealed significant changes in the cytoplasmic membrane structure of the pathogen. This suggests that the antibacterial activity may be linked to the disruption of the microbial membrane. The predominant chemical compound detected in the EtAc-PBR19 was identified as phenol, 3,5-bis(1,1-dimethylethyl), comprising 48.59% of the area percentage. Additionally, PBR19 was found to contain the type II polyketide synthases (PKS type II) gene associated with antibiotic synthesis. The predicted gene product of PKSII was identified as the macrolide antibiotic Megalomicin A. The taxonomic distinctiveness, potent antibacterial effects, and the presence of a gene associated with antibiotic synthesis suggest that PBR19 could be a valuable candidate for further exploration in drug development and synthetic biology. The study contributes to the broader understanding of microbial diversity and the potential for discovering bioactive compounds in less-explored environments.

Trigonometric Bundling Disulfide Unit Starship Synergizes More Effectively to Promote Cellular Uptake

A small molecule disulfide unit technology platform based on dynamic thiol exchange chemistry at the cell membrane has the potential for drug delivery. However, the alteration of the CSSC dihedral angle of the disulfide unit caused by diverse substituents directly affects the effectiveness of this technology platform as well as its own chemical stability. The highly stable open-loop relaxed type disulfide unit plays a limited role in drug delivery due to its low dihedral angle. Here, we have built a novel disulfide unit starship based on the 3,4,5-trihydroxyphenyl skeleton through trigonometric bundling. The intracellular delivery results showed that the trigonometric bundling of the disulfide unit starship effectively promoted cellular uptake without any toxicity, which is far more than 100 times more active than that of equipment with a single disulfide unit in particular. Then, the significant reduction in cell uptake capacity (73–93%) using thiol erasers proves that the trigonometric bundling of the disulfide starship is an endocytosis-independent internalization mechanism via a dynamic covalent disulfide exchange mediated by thiols on the cell surface. Furthermore, analysis of the molecular dynamics simulations demonstrated that trigonometric bundling of the disulfide starship can significantly change the membrane curvature while pushing lipid molecules in multiple directions, resulting in a significant distortion in the membrane structure and excellent membrane permeation performance. In conclusion, the starship system we built fully compensates for the inefficiency deficiencies induced by poor dihedral angles.

Atypical structure of the nuclear membrane, distribution of nuclear pores and lamin B1 in spermatozoa of patients with complete and partial globozoospermia

Globozoospermia is a form of male infertility characterized by spermatozoa with spherical heads lacking acrosomes. The aim of this study was to evaluate ultrastructural and molecular defects in different types of globozoospermia. Semen samples from 12 infertile patients (9 with complete globozoospermia and 3 with partial globozoospermia) and 10 normozoospermic men (control) were examined by transmission electron microscopy and immunocytochemistry with antibodies against lamin B1. The presence of lamin A and progerin was assessed by reverse transcription-PCR. Whole exome sequencing was performed in three patients. In semen samples with complete and partial globozoospermia, lamin B1 was observed at the periphery of sperm nuclei, whereas lamin A and progerin were absent. Nuclear envelope pores were found in spermatozoa from both patient groups, regardless of morphology and chromatin condensation, in contrast to the control group. Non-condensed chromatin was present in 51%–81% of cases of complete globozoospermia and in 36%–79% of cases of partial globozoospermia. Homozygous DPY19L2 and SPATA16 variants were identified in two patients with partial globozoospermia and one patient with complete globozoospermia. An atypical nuclear membrane with abnormal nuclear pore distribution and lamin B1 localization was observed in spermatozoa from patients with both complete and partial globozoospermia. The genetic defects in the DPY19L2 and SPATA16 genes detected in patients from both globozoospermic groups suggest a generalized disruption of nuclear structure in globozoospermia, highlighting the genetic and phenotypic similarities between complete and partial globozoospermia.

Unveiling the cell dynamics during the final shape formation of the tarsus in Drosophila adult leg by live imaging.

Organisms display a remarkable diversity in their shapes. Although substantial progress has been made in unraveling the mechanisms that govern cell fate determination during development, the mechanisms by which fate-determined cells give rise to the final shapes of organisms remain largely unknown. This study describes in detail the process of the final shape formation of the tarsus, which is near the distal tip of the adult leg, during the pupal stage in Drosophila melanogaster. Days-long live imaging revealed unexpectedly complicated cellular dynamics. The epithelial cells transiently form the intriguing structure, which we named the Parthenon-like structure. The basal surface of the epithelial cells and localization of the basement membrane protein initially show a mesh-like structure and rapidly shrink into the membranous structure during the formation and disappearance of the Parthenon-like structure. Furthermore, macrophage-like cells are observed moving around actively in the Parthenon-like structure and engulfing epithelial cells. The findings in this research are expected to significantly contribute to our understanding of the mechanisms involved in shaping the final structure of the adult tarsus.

Impact of DEHP on mitochondria-associated endoplasmic reticulum membranes and reproductive toxicity in ovary

Di(2-ethylhexyl) phthalate (DEHP) is a widely recognized environmental endocrine disruptor that potentially impacts female reproductive function, although the specific mechanisms leading to such impairment remain unclear. A growing body of research has revealed that the endoplasmic reticulum and mitochondrial function significantly influence oocyte quality. The structure of mitochondria-associated endoplasmic reticulum membranes (MAMs) is crucial for facilitating the exchange of Ca2+, lipids, and metabolites. This study aimed to investigate the alterations in the composition and function of MAMs after DEHP exposure and to elucidate the underlying mechanisms of ovarian toxicity. The female mice were exposed to DEHP at doses of 5 and 500 mg/kg/day for one month. The results revealed that DEHP exposure led to reduced serum anti-Müllerian hormone levels and increased atretic follicles in mice. DEHP induced endoplasmic reticulum stress and disrupted calcium homeostasis in oocytes. Furthermore, DEHP impaired the mitochondrial function of oocytes and reduced their membrane potential, and promoting apoptosis. Similar results were observed in human granulosa cells after exposure to mono-(2-ethylhexyl) phthalate (MEHP, metabolites of DEHP) in vitro. Proteomic analysis and transmission electron microscopy revealed modifications in the functional proteins and structure of the MAMs, and the suppression of oxidative phosphorylation pathways. The findings of this investigation provide a new perspective on the mechanism underlying the reproductive toxicity of DEHP in females.

A promising metabolite, 9-aminominocycline, restores the sensitivity of tigecycline against tet(X4)-positive Escherichia coli

The emergence and widespread of tigecycline resistance undoubtedly poses a serious threat to public health globally. The exploration of combination therapies has become preferred antibacterial strategies to alleviate this global burden. In this study, tigecycline-resistant tet(X4)-positive Escherichia coli were selected for adjuvant screening. Interestingly, 9-aminominocycline (9-AMC), one of the tigecycline metabolites, exhibits synergistic antibacterial activity with tigecycline using checkerboard assay. The efficacy in vitro and in vivo was evaluated, and the synergistic mechanism was further explored. The results suggested that 9-AMC combined with tigecycline could inhibit the growth of antibiotic resistant bacteria, efficiently retard the evolution of tet(X4) gene and narrow the drug mutant selection window. In addition, the combination of tigecycline and 9-AMC could destroy the normal membrane structure of bacteria, inhibit the formation of biofilm, remarkably reduce the level of intracellular ATP level, and accelerate the oxidative damage of bacteria. Furthermore, 9-AMC is more stable in the bind of Tet(X4) inactivating enzyme. The transcriptomics analysis revealed that the genes related to the 9-AMC and tigecycline were mainly enriched in ABC transporters. Collectively, the results reveal the potentiation effects on tigecycline and the probability of 9-AMC as a novel tigecycline adjuvant against tet(X4)-positive Escherichia coli, which provides new insights for adjuvant screening.

Advanced Preparation Methods for Ceramic Membrane Materials in Electrochemical Applications

The outstanding thermal, chemical, and mechanical properties of ceramic membranes have attracted increasing attention, offering advantages over polymer and metal counterparts. Exploring the specialized applications of ceramic membranes through various preparation methods poses a daunting challenge for contemporary researchers. Traditional preparation methods are essentially unable to meet the requirements of complex membrane structures. For instance, in ceramic fuel cell applications, cells composed of ceramic membrane materials exhibit high resistance and low conductivity, which seriously hinders the progress of new high-performance ceramic fuel cells. Therefore, it is necessary to improve preparation methods to improve the electrochemical performance of devices composed of ceramic membrane materials. In recent years, breakthroughs in various new processing technologies have propelled the performance of ceramic membrane devices. This paper will focus on the following aspects. Firstly, traditional preparation methods and advanced preparation methods of ceramic membrane materials will be discussed. Secondly, high-performance ceramic membrane materials prepared by different advanced preparation methods are introduced, and the electrochemical properties of the devices composed of ceramic membrane materials are elaborated in combination with different testing and characterization methods. Finally, the prospects and future direction of the preparation of ceramic membrane materials by advanced preparation methods are summarized.

Coenzyme Q10 supplementation affects cellular ionic balance: relevance to aging.

Aging results into disruptive physiological functioning and cellular processes that affect the composition and structure of the plasma membrane. The plasma membrane is the major regulator of ionic homeostasis thatregulates the functioning of membrane transporters and exchangers. Coenzyme Q10 is a lipid-soluble antioxidant molecule that declines during aging and age-associated diseases. The presentstudy aims to explore the role of Coenzyme Q10 supplementation to rats during aging on membrane transporters and redox biomarkers. The studywas conducted on young and old male Wistar rats supplemented with 20 mg/kg b.w. of Coenzyme Q10 per day. After a period of 28days, rats were sacrificed and erythrocyte membrane was isolated. The result exhibits significant decline in biomarkers of oxidative stress in old control rats when compared with young control. The effect of Coenzyme Q10 supplementation was more pronounced in old rats. Thefunctioning of membrane transporters and Na+/H+ exchanger showed potential return to normal levels in the Coenzyme Q10 treated rats. Overall, the results demonstrate that Coenzyme Q10 plays an important role in maintaining redox balance in cells which interconnects with membrane integrity. Thus, Coenzyme Q10 supplementation may play animportant role in protecting age related alterations inerythrocyte membrane physiology.

Robust channel structures of proton exchange membrane fuel cells for uniform clamping pressure to gas diffusion layers

Robust channel structures of proton exchange membrane fuel cells for uniform clamping pressure to gas diffusion layers

Polyvinyl alcohol gel/micro-arc oxidation 3D-printed porous structural aluminium for oil-water separation

Traditional oil-water separation membranes still face challenges in designing membrane structures and pore sizes. In this study, we successfully prepared a PVA@MAO 3D-Al material with an internal porous structure using 3D printing technology and micro-arc oxidation (MAO). Compared to the base 3D-Al material, the fabricated PVA@MAO 3D-Al exhibits excellent wear resistance, with an average friction coefficient reduced by 66% in dry friction and 22% in water lubrication. In electrochemical experiments, corrosion current density decreased by an order of magnitude, indicating higher stability of PVA@MAO 3D-Al in corrosive environments. In oil-water separation experiments, PVA@MAO 3D-Al achieved separation efficiencies exceeding 97% for mixtures of white oil, kerosene, liquid paraffin, and cyclohexane with water. Moreover, even after undergoing 600 cycles of reciprocating friction and exposure to various environmental solutions, the separation efficiency of PVA@MAO 3D-Al for white oil/water mixtures remained above 96%, demonstrating outstanding physical and chemical stability. This suggests that PVA@MAO 3D-Al is suitable for use in extremely harsh environments. This study introduces a simple and efficient approach to manufacturing oil-water separation membranes using 3D printing technology, coupled with MAO technology to enhance the base material's performance. The combination of these techniques opens up new avenues in the field of oil-water separation.

SIRT1-mediated tunnelling nanotubes may be a potential intervention target for arsenic-induced hepatocyte senescence and liver damage

Arsenic, a widespread environmental poison, can cause significant liver damage upon exposure. Mitochondria are the most sensitive organelles to external factors. Dysfunctional mitochondria play a crucial role in cellular senescence and liver damage. Tunnelling nanotubes (TNTs), membrane structures formed between cells, with fibrous actin (F-actin) serving as the scaffold, facilitate mitochondrial transfer between cells. Notably, TNTs mediate the delivery of healthy mitochondria to damaged cells, thereby mitigating cellular damage. Although limited studies have suggested that F-actin may be modulated by the longevity gene SIRT1, the association between arsenic-induced liver damage and this mechanism remains unexplored. The findings of the current study indicate that arsenic suppresses SIRT1 and F-actin in the rat liver and MIHA cells, impeding the formation of TNTs and mitochondrial transfer between MIHA cells, thereby playing a pivotal role in mitochondrial dysfunction, cellular senescence and liver damage induced by arsenic. Notably, increasing SIRT1 levels effectively mitigated liver mitochondrial dysfunction and cellular senescence triggered by arsenic, highlighting SIRT1's crucial regulatory function. This research provides novel insights into the mechanisms underlying arsenic-induced liver damage, paving the way for the development of targeted preventive and therapeutic drugs to address arsenic-induced liver damage.

Residual Membrane Fluidity in Mycobacterial Cell Envelope Layers under Extreme Conditions Underlines Membrane-Centric Adaptation.

One of the routes for adaptation to extreme environments is via remodeling of cell membrane structure, composition, and biophysical properties rendering a functional membrane. Collective studies suggest some form of membrane feedback in mycobacterial species that harbor complex lipids within the outer and inner cell wall layers. Here, we study the homeostatic membrane landscape of mycobacteria in response to high hydrostatic pressure and temperature triggers using high pressure fluorescence, mass and infrared spectroscopies, NMR, SAXS, and molecular dynamics simulations. Our findings reveal that mycobacterial membrane possesses unique and lipid-specific pressure-induced signatures that attenuate progression to highly ordered phases. Both inner and outer membrane layers exhibit phase coexistence of nearly identical lipid phases keeping residual fluidity over a wide range of temperature and pressure, but with different sensitivities. Lipidomic analysis of bacteria grown under pressure revealed lipidome remodeling in terms of chain length, unsaturation, and specific long-chained characteristic mycobacterial lipids, rendering a fluid bacterial membrane. These findings could help understand how bacteria may adapt to a broad spectrum of harsh environments by modulating their lipidome to select lipids that enable the maintenance of a fluid functional cell envelope.

P-117 Extracellular vesicles from fallopian tubal fluid benefit human embryo development in vitro

Abstract Study question Do extracellular vesicles (EVs) from Fallopian tubes benefit human embryo development, and how do they affect preimplantation embryo development? Summary answer The Fallopian tubal EVs can be internalized by human embryos, and they contain miR-21-5p that downregulated P53 in blastocysts. What is known already EVs in the Fallopian tubes are identified as key mediators in embryo-oviduct interactions that contribute to a successful pregnancy in vivo. We previously showed Fallopian tubal EVs can benefit mouse embryo development in vitro. However, if a similar phenomenon can be observed in human embryos and what is the key component in Fallopian tubal EVs remains elusive. Study design, size, duration The EVs were isolated from the luminal fluid of human Fallopian tubes (n = 23). Immature human oocytes were collected and in vitro matured and fertilized, and 2-pronuclei embryos were included in this study and randomly divided (n = 87). We cocultured these zygotes with Fallopian tubal EVs until the blastocyst stage. Further, two-cell mouse embryos were used to explore the expression levels of miRNAs in Fallopian tubal EVs. The effects of miR-21-5p on mouse embryos were analyzed. Participants/materials, setting, methods EVs were isolated using ultracentrifugation. The uptake of labeled EVs by human embryos was analyzed using confocal microscopy. The fragmentation of the day-3 embryos and the blastocyst rate were compared between the control and the EV-treatment group. Then the stage-specific expression of miRNAs was compared in mouse embryos that were either developed in vivo or cultured in vitro. miR-21-5p were supplemented to the culture medium and the p53-related apoptosis in embryos was evaluated. Main results and the role of chance EVs were measured less than 200 nm in diameter with a typical bi-layer membrane structure and expressed protein markers Heat shock protein 70 (HSP70) and CD9. Most of the fluorescence-labeled EVs were attached to the zona pellucida within 2 h of co-culture. However, human embryos internalized EV within 4 h, with fluorescence signals observed in embryonic cells. The fragmentation rate was decreased and the blastocyst rate was increased by EVs. miR-21-5p, which was highly enriched in EVs, was found to be expressed at a significantly lower level in in-vitro-cultured mouse embryos compared to the in-vivo-developed embryos, through the two-cell stage to the eight-cell stage. miR-21-5p agomir supplementation to the culture medium was found to increase the mouse blastocyst formation rate, decrease apoptosis, and downregulate the P53 expression level in mouse blastocysts. Limitations, reasons for caution Though we observed that Fallopian tubal EVs could be internalized by human embryos and improve embryo development morphologically, the subsequent mechanism exploration was conducted using mouse embryos. Whether the stage-specific expression level of miR-21-5p and the effects of miR-21-5p are the same in human embryos remains to be determined. Wider implications of the findings This study showed miRNAs in Fallopian tubal EVs can act as embryonic survival signals, which opens the insight into further explorations to demonstrate the molecular mechanisms during early embryo development, as well as holds the potential to optimize the culture medium used in ART in the future. Trial registration number 2022YFC2702503

P-040 The characteristic of human seminal plasma extracellular vesicle (SPEVs) profiles with different sperm features in a large cohort of 309 Taiwanese men

Abstract Study question To investigate human seminal plasma extracellular vesicle profiles in different sperm characteristics and their potential clinical application. Summary answer Normozoospermic semen has significantly higher SPEV concentration than asthenozoospermic or oligozoospermic samples. Moreover, SPEV concentration was highly correlated with total motile sperm count. What is known already Seminal plasma extracellular vesicles (SPEVs) are cell-derived membrane structures that carry proteins, nucleic acid, and lipids, which can modify the constitution and biological function of sperm. However, the characteristics of SPEVs in different sperm features remained unclear. Study design, size, duration From January 2021 to September 2023, 309 men who visited the NCKUH andrology clinic agreed to collect semen samples for this study, which the Institutional Review Board has approved. Participants/materials, setting, methods Semen parameters were measured by the X1 CASA system (Bonraybio, Taiwan). SPEVs were isolated by size exclusion chromatography column and ExoQuick™. Next, the SPEVs’ concentration and size distribution were performed with nanoparticle tracking analysis. The Kruskal-Wallis test calculated comparison in multiple groups, and Dunn’s multiple comparison tests accessed group-group comparison. The Pearson correlation coefficient r of exosome concentration with individual sperm parameters was calculated. A p-value less than 0.05 was set as statistical significance. Main results and the role of chance Among them, 59 semen samples were presented with normozoospermia, 36 were oligozoospermia, 73 were asthenozoospermia, and 141 samples had no sperm in semen. Among these 141 azoospermic men, 89 men are characterized by non-obstructive azoospermia (NOA), while the other 52 men had a vasectomy. Our data showed that normozoospermic semen has significantly higher SPEV concentration than asthenozoospermic or oligozoospermic semen samples (26 x109 [IQR 17.25 x109-56.25 x109] versus 12 x109 [IQR 5.6 x109-19.5 x109] versus 15.5 x109 [IQR 8.575 x109-26.75 x109], p = 0.0001). Nevertheless, azoospermic semen has the lowest SPEV concentrations. The concentration of SPEVs from infertile men diagnosed with NOA is slightly lower than vasectomized men (3.9 x109 [IQR 1.875 x109-7.675 x109] versus 5.4 x109 [IQR 2.9 x109-8 x109], p = 0.0001). The Pearson r coefficient of SPEV concentration with sperm concentration, progressive motility, and total motile sperm count was 0.238, 0.303, and 0.451, respectively. (P < 0.0001) Limitations, reasons for caution Because our data were collected from Taiwanese men, it is not yet known whether SPEV profiles differ among races. Wider implications of the findings Human SPEV concentration and its bio-content may be a potential non-invasive biomarker to predict the male reproductive outcome. Trial registration number not applicable

Effect of abamectin on osmoregulation in red swamp crayfish (Procambarus clarkii).

As a widely used pesticide, abamectin could be a threat to nontarget organisms. In this study, the toxic mechanism of abamectin on osmoregulation in Procambarus clarkii was explored for the first time. The results of this study showed that with increasing abamectin concentration, the membrane structures of gill filaments were damaged, with changes in ATPase activities, transporter contents, biogenic amine contents, and gene expression levels. The results of this study indicated that at 0.2mg/L abamectin, ion diffusion could maintain osmoregulation. At 0.4mg/L abamectin, passive transport was inhibited due to damage to the membrane structures of gill filaments, and active transport needed to be enhanced for osmoregulation. At 0.6mg/L abamectin, the membrane structures of gill filaments were seriously damaged, and the expression level of osmoregulation-related genes decreased, but the organisms were still mobilizing various transporters, ATPases, and biogenic amines to address abamectin stress. This study provided a theoretical basis for further study of the effects of contaminations in aquatic environment on the health of crustaceans.

Meningeal lymphatic supporting cells govern the formation and maintenance of zebrafish mural lymphatic endothelial cells

The meninges are critical for the brain functions, but the diversity of meningeal cell types and intercellular interactions have yet to be thoroughly examined. Here we identify a population of meningeal lymphatic supporting cells (mLSCs) in the zebrafish leptomeninges, which are specifically labeled by ependymin. Morphologically, mLSCs form membranous structures that enwrap the majority of leptomeningeal blood vessels and all the mural lymphatic endothelial cells (muLECs). Based on its unique cellular morphologies and transcriptional profile, mLSC is characterized as a unique cell type different from all the currently known meningeal cell types. Because of the formation of supportive structures and production of pro-lymphangiogenic factors, mLSCs not only promote muLEC development and maintain the dispersed distributions of muLECs in the leptomeninges, but also are required for muLEC regeneration after ablation. This study characterizes a newly identified cell type in leptomeninges, mLSC, which is required for muLEC development, maintenance, and regeneration.

Hierarchical biocatalytic membranes embedded with trypsin–inorganic hybrid nanoflowers for effective β-lactoglobulin hydrolysis

β-lactoglobulin (β-LG) is a significant allergen in milk. Enzymatic hydrolysis of β-LG produces peptides with low allergenicity and improved functionality. The biocatalytic membranes combine enzyme function and membrane separation in one step, but is still challenging for proteolysis. Herein, the biocatalytic membranes embedded with trypsin-inorganic hybrid nanoflowers are developed by a facile and green method for β-LG hydrolysis. Ethylene vinyl alcohol copolymer (EVAL) nanofibers are fabricated as 3D scaffolding on the membrane surface and trypsin-copper phosphate nanoflowers are in-situ grown in the porous structure of membranes. The nanoflowers are uniformly entrapped in the EVAL nanofiber layer and preferentially grow in the EVAL nanofibers layer, leading to the hierarchical structure of membranes. The trypsin loading of the nanoflowers membrane is approximate to 282.1µg/cm2. Lower Michaelis-Menten constants Km prove the better affinity of Cu3(PO4)2-TR nanoflower membrane with substrates during filtration than that in static mode, even than free trypsin. The hierarchical structure of the membranes ensures both the enhanced trypsin-substrate contacts and low mass transfer resistance during the β-LG filtration. This work not only presents a novel concept of enzyme immobilized biocatalytic membranes, but also offers a sustainable solution for high-performance proteolysis.

Effects of FMWCNT inclusions on PVDF/FMWCNT membranes structure and characteristics

Effects of FMWCNT inclusions on PVDF/FMWCNT membranes structure and characteristics

Organic-organic interfacial polymerization for the ultrathin polyamide organic solvent nanofiltration membranes

There is an increasing demand for advanced membranes that exhibit both high perm-selectivity and good stability in organic solvents, particularly for organic solvent nanofiltration (OSN). Traditional methods of synthesizing thin films using conventional interfacial polymerization (CIP) have been limited by the use of water-soluble monomers, which has hindered the development of high-performance membranes. To address this issue, a new method called organic-organic interfacial polymerization (OOIP) has been proposed. This method allows for the use of aromatic amines that are not water-soluble in the fabrication of ultrathin polyamide (PA) (<40 nm) thin film composite (TFC) membranes. By investigating five different organic solvents (tetrahydrofuran, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide) with varying water content as the organic phase for a water-insoluble benzidine monomer, two diffusion models of monomers were identified that resulted in different membrane structures and degrees of network crosslinking. The ultrathin PA membranes produced using tetrahydrofuran-H2O and N,N-dimethylformamide-H2O, along with solvent activation, demonstrated high methanol permeances of 11.4 L m−2 h−1 bar−1 and 6.0 L m−2 h−1 bar−1, respectively, while maintaining exceptional rejections of over 99.0 % for small molecules with molecular weights greater than 452 g mol−1. The OOIP method is scalable and reproducible, making it suitable for large-scale membrane production. This innovative approach shows great potential for advancing OSN technology and providing efficient and cost-effective separation solutions for various industries.

Fluid-structure interaction in inflatable membrane structures: A featured study of mechanical behavior

This paper presents a comprehensive analysis of fluid-structure interaction (FSI) effects on the behavior of inflatable membrane structures under wind loads, aiming to enhance the understanding of the structural performance. We adopted a mixed-methods approach, incorporating a numerical simulation based on the RNG k-ε turbulence model. The work focused on a semi-cylindrical air-supported membrane structure examining the effects of varying wind directions, speeds, and internal pressures. Specifically, we investigated the displacement and stress on the inflatable membrane structure under wind velocities of 12, 15, and 18 m/s, taking into account the internal air pressure. Consequently, we determined the influence coefficients for displacement and stress, representing the ratio of FSI effects to those in a static case. Our findings indicate that the displacement coefficient is inversely related to internal pressure, whereas the stress coefficient directly correlates with wind speed. The maximum displacement and stress under FSI conditions can be calculated by applying an influence coefficient to the static case results. The findings from this study offer a convenient and reliable method for predicting the actual structural response. This paper provides valuable insights for the design and optimization of inflatable membrane structures to withstand wind loads, a topic that has been underexplored in previous studies. Future studies should investigate additional cases to further enhance the reliability of this method.