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The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures. [ABSTRACT FROM AUTHOR]

The present paper investigated the characteristic of the vibration of a membrane structure under impact load based on a series of experiments. Eight cases with different pretension forces by varying the pretension load in the lateral direction were carried out. The impact loads were applied on the center position of the membrane. The results of frequency, vibration amplitude, and damping ratio were discussed. It is shown that there is a main vibration mode with different main frequencies in the vibrations and the duration is the same under the different impact loads. The frequency is linear to the pretension force, and the amplitude of the vibration decreases by an exponential function determined by the parameter of the damping ratio. When the pretension force exceeded a threshold (6.2% of strength), the maximum amplitude and vibration duration tend to be a fixed value. [ABSTRACT FROM AUTHOR]

In urban open spaces, especially in large cities with warm climates, users are experiencing high thermal loads, which causes thermal discomfort. Thermal comfort in open spaces can be improved; by shading. The problem is shading and protecting open spaces from stresses caused by overheating of the earth's surface and environment. The importance of shade and reducing radiation in achieving thermal comfort in open urban spaces is to increase human presence, create climate change, increase comfort conditions. Recognizing factors that create shadows, such as canopies and their characteristics, can create a favorable space to enjoy the capabilities of outdoor space. New membranes have many characteristics of nomadic tents, and, due to creating shade and natural ventilation, are very suitable for areas with hot climates. Introducing an optimal model and dimensions of a lightweight membrane canopy can create outdoor thermal comfort and increase the efficiency of outdoor spaces. In this paper, library, field, and simulation studies have been used. According to field studies, the presence of membrane canopy can cause temperature differences up to 7.8 C. The simulation results with Ansys, ENVI-met, and Ladybug showed that the membrane canopy cools the space below and prevents overheating. Between four canopy models, the saddle canopy is suitable with a 40.63% impact on the environment and creates cooler space under the canopy. Therefore, a lightweight saddle membrane canopy with dimensions of 5*5 m^2 and a useful height of 3 meters is introduced as a suitable model of membrane canopy for the hot climate of Semnan.

Polymeric membrane technology has been accepted as one of the significant tools in separation and purification process. Membrane preparation, modification and characterization are the key steps for selection of membrane in a specific applications. This review work may offer a point of reference to the researchers who are concern in fabrication of polymeric membrane via phase inversion method dedicated on immersion precipitation. In this review article, special consideration has been paid to the evaluation of polymeric membrane properties such as casting solution viscosity, coagulation value, membrane morphology, structure, chemical composition, porosity, shrinkage, hydrophilicity, water uptake, ion exchange capacity, pHresponsive behaviour, permeation, solute rejection, fouling behaviour and cleaning efficiency. This review article encompasses the applications of polymeric membrane in various fields. [ABSTRACT FROM AUTHOR]

[Display omitted] Continuous flow injection is a key technology for serial crystallography measurements of protein crystals suspended in the lipidic cubic phase (LCP). To date, there has been little discussion in the literature regarding the impact of the injection process itself on the structure of the lipidic phase. This is despite the fact that the phase of the injection matrix is critical for the flow properties of the stream and potentially for sample stability. Here we report small-angle X-ray scattering measurements of a monoolein:water mixture during continuous delivery using a high viscosity injector. We observe both an alignment and modification of the LCP as a direct result of the injection process. The orientation of the cubic lattice with respect to the beam was estimated based on the anisotropy of the diffraction pattern and does not correspond to a single low order zone axis. The solvent fraction was also observed to impact the stability of the cubic phase during injection. In addition, depending on the distance traveled by the lipid after exiting the needle, the phase is observed to transition from a pure diamond phase (Pn 3 m) to a mixture containing both gyriod (Ia 3 d) and lamellar ( L α ) phases. Finite element modelling of the observed phase behaviour during injection indicates that the pressure exerted on the lipid stream during extrusion accounts for the variations in the phase composition of the monoolein:water mixture. [ABSTRACT FROM AUTHOR]

The cartilage tissue is neither supplied with blood nor innervated, so it cannot heal by itself. Thus, its reconstruction is highly challenging and requires external support. Cartilage diseases are becoming more common due to the aging population and obesity. Among young people, it is usually a post-traumatic complication. Slight cartilage damage leads to the spontaneous formation of fibrous tissue, not resistant to abrasion and stress, resulting in cartilage degradation and the progression of the disease. For these reasons, cartilage regeneration requires further research, including use of new type of biomaterials for scaffolds. This paper shows cartilage characteristics within its most frequent problems and treatment strategies, including a promising method that combines scaffolds and human cells. Structure and material requirements, manufacturing methods, and commercially available scaffolds were described. Also, the comparison of poly(L-lactide) (PLLA) and polyethersulfone (PES) 3D membranes obtained by a phase inversion method using nonwovens as a pore-forming additives were reported. The scaffolds' structure and the growth ability of human chondrocytes were compared. Scaffolds' structure, cells morphology, and protein presence in the membranes were examined with a scanning electron microscope. The metabolic activity of cells was tested with the MTT assay. The structure of the scaffolds and the growth capacity of human chondrocytes were compared. Obtained results showed higher cell activity and protein content for PES scaffolds than for PLLA. The PES membrane had better mechanical properties (e.g. ripping), greater chondrocytes proliferation, and thus a better secretion of proteins which build up the cartilage structure. [ABSTRACT FROM AUTHOR]

Virus removal filtration is a critical step in the manufacture of monoclonal antibody products, providing a robust size‐based removal of both enveloped and non‐enveloped viruses. Many monoclonal antibodies show very large reductions in filtrate flux during virus filtration, with the mechanisms governing this behavior and its dependence on the properties of the virus filter and antibody remaining largely unknown. Experiments were performed using the highly asymmetric Viresolve® Pro and the relatively homogeneous Pegasus™ SV4 virus filters using a highly purified monoclonal antibody. The filtrate flux for a 4 g/L antibody solution through the Viresolve® Pro decreased by about 10‐fold when the filter was oriented with the skin side down but by more than 1000‐fold when the asymmetric filter orientation was reversed and used with the skin side up. The very large flux decline observed with the skin side up could be eliminated by placing a large pore size prefilter directly on top of the virus filter; this improvement in filtrate flux was not seen when the prefilter was used inline or as a batch prefiltration step. The increase in flux due to the prefilter was not related to the removal of large protein aggregates or to an alteration in the extent of concentration polarization. Instead, the prefilter appears to transiently disrupt reversible associations of the antibodies caused by strong intermolecular attractions. These results provide important insights into the role of membrane morphology and antibody properties on the filtrate flux during virus filtration. [ABSTRACT FROM AUTHOR]

The polymer electrolyte membrane and its contact with electrodes has a significant effect on the performance of fuel and electrolysis cells but the choice of commercially available membranes is limited. In this study, membranes for direct methanol fuel cells (DMFCs) were made by ultrasonic spray deposition from commercial Nafion solution; the effect of the drying temperature and presence of high boiling solvents on the membrane properties was then analyzed. When choosing suitable conditions, membranes with similar conductivity, water uptake, and higher crystallinity than comparable commercial membranes can be obtained. These show similar or superior performance in DMFC operation compared to commercial Nafion 115. Furthermore, they exhibit low permeability for hydrogen, which makes them attractive for electrolysis or hydrogen fuel cells. The findings from our work will allow for the adjustment of membrane properties to the specific requirements of fuel cells or water electrolysis, as well as the inclusion of additional functional components for composite membranes.

Membrane asymmetry is critical for maintenance of several different processes such as cell signaling, apoptosis, and vesicular transport in various eukaryotic systems. Flippases of the P4-ATPase family are associated with flipping phospholipids from the luminal or exoplasmic leaflet to the cytosolic leaflet. P4-ATPases belong to the P-type ATPase family, which are activated by phosphorylation and couple ATPase activity to substrate translocation. These proteins possess a transmembrane domain responsible for substrate transport, while the cytosolic machinery performs the necessary ATP hydrolysis for this process. Several high-resolution structures of human or yeast P4-ATPases have recently been resolved, but a comprehensive overview of the changes for reaction cycle in different members was crucial for future research. In this review, we have compiled available data reflecting the reaction cycle-associated changes in conformation of P4-ATPases. Together, this will provide an improved understanding of the similarities and differences between these members, which will drive further structural, functional, and computational studies to understand the mechanisms of these flippases., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The plasma membrane of a biological cell is a complex assembly of lipids and membrane proteins, which tightly regulate transmembrane transport. When a cell is exposed to strong electric field, the membrane integrity becomes transiently disrupted by formation of transmembrane pores. This phenomenon termed electroporation is already utilized in many rapidly developing applications in medicine including gene therapy, cancer treatment, and treatment of cardiac arrhythmias. However, the molecular mechanisms of electroporation are not yet sufficiently well understood; in particular, it is unclear where exactly pores form in the complex organization of the plasma membrane. In this study, we combine coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis to identify how formation of pores depends on the local lipid organization. We show that pores do not form homogeneously across the membrane, but colocalize with domains that have specific features, the most important being high density of polyunsaturated lipids. We further show that knowing the lipid organization is sufficient to reliably predict poration sites with machine learning. Additionally, by analysing poration kinetics with Bayesian survival analysis we show that poration does not depend solely on local lipid arrangement, but also on membrane mechanical properties and the polarity of the electric field. Finally, we discuss how the combination of atomistic and coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis can guide the design of future experiments and help us to develop an accurate description of plasma membrane electroporation on the whole-cell level. Achieving this will allow us to shift the optimization of electroporation applications from blind trial-and-error approaches to mechanistic-driven design.

By coating the alveolar air-liquid interface, lung surfactant overwhelms surface tension forces that, otherwise, would hinder the lifetime effort of breathing. Years of research have provided a picture of how highly hydrophobic and specialized proteins in surfactant promote rapid and efficient formation of phospholipid-based complex three-dimensional films at the respiratory surface, highly stable under the demanding breathing mechanics. However, recent evidence suggests that the structure and performance of surfactant typically isolated from bronchoalveolar lung lavages may be far from that of nascent, still unused, surfactant as freshly secreted by type II pneumocytes into the alveolar airspaces. In the present work, we report the isolation of lung surfactant from human amniotic fluid (amniotic fluid surfactant, AFS) and a detailed description of its composition, structure, and surface activity in comparison to a natural surfactant (NS) purified from porcine bronchoalveolar lavages. We observe that the lipid/ protein complexes in AFS exhibit a substantially higher lipid packing and dehydration than in NS. AFS shows melting transitions at higher temperatures than NS and a conspicuous presence of nonlamellar phases. The surface activity of AFS is not only comparable with that of NS under physiologically meaningful conditions but displays significantly higher resistance to inhibition by serum or meconium, agents that inactivate surfactant in the context of severe respiratory pathologies. We propose that AFS may be the optimal model to study the molecular mechanisms sustaining pulmonary surfactant performance in health and disease, and the reference material to develop improved therapeutic surfactant preparations to treat yet unresolved respiratory pathologies. [ABSTRACT FROM AUTHOR]

Multifunctional membrane space structures have been developed in the past to realize solar arrays, array antennas, and other applications. However, the deployment of a folded membrane often requires fluctuating forces with high peaks, caused by the stiffness of the crease lines. This study proposes the use of a plain-woven textile as the base membrane for the planar deployment structures primarily because of its high packaging efficiency. The deployment forces required for the folded plain-woven textile structures to be employed in future space applications are experimentally measured. The deployment forces are compared between the proposed textile structures and the conventional film-based membranes to characterize the deployment behavior of the textile structures. Two types of experiments are conducted in this study for the one-dimensional deployment of v-folded membranes and the two-dimensional deployment of quarter Flasher origami structures, respectively. The advantages presented by the deployable textiles are as follows: (i) they require smaller and smoother deployment forces, and (ii) they are insensitive to imperfect boundary conditions. These features are important for the reliable deployment of future space structures. • Membrane structures will be compactly stored and deployed more smoothly when woven textile is used. • The attachment of thin-film devices on the textile will enable innovative space applications. • The forces for one-dimensional and two-dimensional deployment were experimentally measured. • Comparison of deployment forces between polymer film and textile clarified unique characteristics. • Extremely low shear stiffness of the plain-woven textile results in smaller deployment force and smoother deployment. [ABSTRACT FROM AUTHOR]

This paper focuses on the deployment dynamics of space membrane structures, placing an emphasis on membranes folded and deployed in a manner in which inter-membrane interaction must be taken into account in order to produce accurate results. This is motivated by the ongoing development of the HELIOS mission; a spacecraft component scheduled to launch in 2022, which is expected to have high membrane entanglements during its deployment. Contact mechanics are added to a multi-particle method-based model to be able to simulate HELIOS-like membrane deployment configurations. The resulting deployment simulation is analyzed using the work rate of the deployment structure and membrane stress during deployment. Several deployment configurations are tested, and factors that amplify or suppress entanglement phenomena are identified. [ABSTRACT FROM AUTHOR]

The plasma membrane (PM) comprises distinct subcellular domains with diverse functions that need to be dynamically coordinated with intracellular events, one of the most impactful being mitosis. The Kv2.1 voltage-gated potassium channel is conditionally localized to large PM clusters that represent specialized PM:endoplasmic reticulum membrane contact sites (PM:ER MCS), and overexpression of Kv2.1 induces more exuberant PM:ER MCS in neurons and in certain heterologous cell types. Localization of Kv2.1 at these contact sites is dynamically regulated by changes in phosphorylation at one or more sites located on its large cytoplasmic C terminus. Here, we show that Kv2.1 expressed in COS-1 cells undergoes dramatic cell cycle-dependent changes in its PM localization, having diffuse localization in interphase cells, and robust clustering during M phase. The mitosis-specific clusters of Kv2.1 are localized to PM:ER MCS, and M phase clustering of Kv2.1 induces more extensive PM:ER MCS. These cell cycle-dependent changes in Kv2.1 localization and the induction of PM:ER MCS are accompanied by increased mitotic Kv2.1 phosphorylation at several C-terminal phosphorylation sites. Phosphorylation of exogenously expressed Kv2.1 is significantly increased upon metaphase arrest in COS-1 and CHO cells, and in a pancreatic β cell line that express endogenous Kv2.1. The M phase clustering of Kv2.1 at PM:ER MCS in COS-1 cells requires the same C-terminal targeting motif needed for conditional Kv2.1 clustering in neurons. The cell cycle-dependent changes in localization and phosphorylation of Kv2.1 were not accompanied by changes in the electrophysiological properties of Kv2.1 expressed in CHO cells. Together, these results provide novel insights into the cell cycle-dependent changes in PM protein localization and phosphorylation.

Abstract Unique membrane structures endow membranes with controlled ion transport properties in both biological and artificial systems, and they have shown broad application prospects from industrial production to biological interfaces. Herein, current advances in nanochannel‐structured membranes for manipulating ion transport are reviewed from the perspective of membrane structures. First, the controllability of ion transport through ion selectivity, ion gating, ion rectification, and ion storage is introduced. Second, nanochannel‐structured membranes are highlighted according to the nanochannel dimensions, including single‐dimensional nanochannels (i.e., 1D, 2D, and 3D) functioning by the controllable geometrical parameters of 1D nanochannels, the adjustable interlayer spacing of 2D nanochannels, and the interconnected ion diffusion pathways of 3D nanochannels, and mixed‐dimensional nanochannels (i.e., 1D/1D, 1D/2D, 1D/3D, 2D/2D, 2D/3D, and 3D/3D) tuned through asymmetric factors (e.g., components, geometric parameters, and interface properties). Then, ultrathin membranes with short ion transport distances and sandwich‐like membranes with more delicate nanochannels and combination structures are reviewed, and stimulus‐responsive nanochannels are discussed. Construction methods for nanochannel‐structured membranes are briefly introduced, and a variety of applications of these membranes are summarized. Finally, future perspectives to developing nanochannel‐structured membranes with unique structures (e.g., combinations of external macro/micro/nanostructures and the internal nanochannel arrangement) for mediating ion transport are presented.

The discoloration of building facades due to airborne algae is observed in our surroundings. The growth conditions of these algae are not yet fully understood, and efficient measures for preventing the growth of the algae are not presently available. The objective of this study was to investigate the effects of the ambient environment and building structure on algal growth. A residential building in a cold region of Japan was surveyed. The roof was a multi-layered structure comprising a semi-transparent film, an air layer, and a layer of insulation from the outside, supported by rafters. The soiled state was visually observed by taking photographs. On the northeast (NE) and northwest (NW) roofs, several black stripes appeared 4 months after cleaning. The soiling increased in the spring and autumn. The soiling first appeared on the film backed by the rafter and then extended to the film backed by the air layer. The condensation time during the day in the rafter part was longer than that in the air-layer part. Condensation occurred during the night, but its frequency exhibited no dependence on the orientation of the roof. Algae tend to die when exposed to an environment with a temperature higher than 45°C. The NE roof had the shortest period with a surface temperature of >45°C. These measurements agreed well with the survey results, which indicated that the soiling mainly occurred on the NE and NW sides of the roofs. The time for algal growth was estimated under the assumption that algae can grow at surface temperatures ranging from 0 to 45°C, in agreement with the observed soiling. The observed soiling changes were well explained by the algal population calculated via a growth predictive model according to the algal temperature and relative humidity. [ABSTRACT FROM AUTHOR]

Cardiolipin (CL) localizes to curved membranes such as cristae in mitochondria as well as cell poles and division sites in rod-shaped bacteria. CL is believed to stabilize the membrane curvature by localizing to sites of negative curvature. However, this hypothesis has not been tested because of a lack of appropriate tools to distinguish CL inside and outside lipid bilayers. In this study, we provided the first evidence that CL localized to regions of negative curvature in Escherichia coli using the novel CL probe erylysin A-EGFP (EryA-EGFP). Staining in E.coli illustrated that CL localized to the inner leaflets at cell poles and the outer leaflets at division sites. Furthermore, we revealed that EryA-EGFP inhibited cytokinesis. We propose that cytokinesis completes after CL in the outer leaflets transfers to the inner leaflets at division sites by inspecting the mechanism of inhibition of cytokinesis. Moreover, the cytoskeletal protein RodZ was abnormally distributed when cytokinesis was inhibited by EryA-EGFP, suggesting that RodZ participates in cytokinesis. In summary, we revealed the detailed distribution of CL and proposed a new model of cytokinesis. [ABSTRACT FROM AUTHOR]

We studied the physico-chemical properties of lipids of the most important organs (the liver and brain) of mice that received nanoliposomal complexes of different compositions in a long-term diet (3 months). The components of the nanoliposomal complexes included soy phosphatidylcholine, clove essential oil, fish oil, and sodium caseinate. We prepared liposomes by mixing lipids from the investigated organs and determined whether they were able to initiate oxidation. We also determined the structure of the lipid bilayer in regions of localization of 5-doxyl and 16-doxyl stearic acids spin probes, and liposome size and charge. It was found that all the studied parameters changed significantly with the age of the animal: lipids from both organs had a reduced capacity for oxidation, microviscosity decreased and cells were enlarged; the size of liposomes from liver lipids increased, whereas the size of liposomes from brain lipids decreased; after consuming this diet the studied values were closer to those typical of young animals. A correlation was found between the rate of lipid oxidation and microviscosity and changing fatty acid composition, whereas liposome size correlated with the parameter of the arrangement of lipid layers over the membrane surface. [ABSTRACT FROM AUTHOR]

Residual plasmin activity in whole ultra-instantaneous UHT (UI-UHT) milk causes rapid fat rise during storage, seriously affecting consumers' purchase intentions. In this work, the molecular mechanisms underlying fat destabilization in whole UI-UHT milk by added plasmin were investigated based on the hydrolysis behavior of interfacial proteins. By using SDS-PAGE and peptidomic analysis, we found that the hydrolysis of interfacial proteins by plasmin led to a decrease in the amount and coverage of interfacial proteins and an increase in zeta-potential value, causing the flocculation and coalescence of fat globules. Moreover, the hydrolysis pattern varied in different categories of interfacial proteins by plasmin. In total, 125 peptides in all samples were identified. Plasmin tended to hydrolyze most major milk fat globule membrane (MFGM) proteins into protein fragments (>10 kDa) rather than peptides (<10 kDa). In contrast, peptides derived from caseins were more preferentially identified within a relatively short incubation time. It was the co-hydrolysis of caseins and some major MFGM proteins as anchors that destroyed the stability of MFGM. Furthermore, studies on the effect of trilayer membrane structure remaining at the interface on the hydrolysis rate of major MFGM proteins by plasmin revealed that ADPH and BTN were very sensitive to plasmin action, while PAS 7 was very resistant to plasmin action. Overall, membrane structure reduced the susceptibility of some major MFGM proteins to plasmin and provided protective effects. Therefore, this study provided important insights into the hydrolysis behavior of interfacial proteins in whole UI-UHT milk induced by plasmin. • Plasmin tended to hydrolyze most major MFMG proteins into protein fragments. • The relationships between interfacial behavior and fat stability were revealed. • At the interface, ADPH and BTN were very sensitive to the action of plasmin. • Membrane structure reduced the susceptibility of major MFGM proteins to plasmin. • PAS 7 was more resistant to plasmin than other major MFGM proteins. [ABSTRACT FROM AUTHOR]

The mechanism of Amphotericin B at the membrane is still subject of debate, with the prevailing hypothesis being the formation of pores. The activity of these pores is influenced by various factors. Recently aggregation in solution and insertion in the membrane had been highlighted as crucial for action of the drug Here we investigated the effect of applied pressure on the activity of Amphotericin B. Our findings demonstrate that applied pressure of 50 mmHg is sufficient to enhance the activity. We interpreted the results as supporting the idea that pressure fractures the membrane and promotes the insertion of the polyene [ABSTRACT FROM AUTHOR]

In recent years, inferring phylogenies has attracted lots of attention in both academic community and various application fields. Phylogenetic inference usually consists of a couple of evolutionary relationships, which can be represented as a phylogenetic tree. The phylogenetic reconstruction problem can be defined as an optimization problem, targeting at finding the most eligible tree among all possible topologies according to a selected criterion. Since the combinatorial number of possible topologies exceeds tolerance, various heuristic and metaheuristic methods have been proposed to find approximate solutions according to the selected criterion. However, different criterions are based on different principle and conflict with each other basically. In this line, scholars has proposed multi-objective evolutionary algorithm (MOEA) based on diverse criteria. Nevertheless, MOEA has suffered unbearable time consumption due to its inherent drawbacks of computational complexity and convergence. By studying the independence between the sub-populations in each time-consuming step of MOEA, the steps without global information can be designed to be executed in parallel, which can fundamentally address computational problems. Effective parallel algorithms designed with the characteristics of modern multicore clusters can solve such problems. In this sense, we propose a parallelized multi-objective evolutionary algorithm (MOEA-MC) by deploying on Spark, which added consensus into evolutionary algorithm to improve the quality of convergence and used membrane structure to keep equal solutions under different weights. In order to assess the performance achieved by the proposal, we have performed comparison among different methods on three real-world datasets separately. The results have certified that the solutions derived from MOEA-MC are superior to traditional methods in all studied datasets. And parallelized MOEA-MC can get dominant position and optimal Pareto-frontier simultaneously within minimal runtime.

Protein toxins from tarantula venom alter the activity of diverse ion channel proteins, including voltage, stretch, and ligand-activated cation channels. Although tarantula toxins have been shown to partition into membranes, and the membrane is thought to play an important role in their activity, the structural interactions between these toxins and lipid membranes are poorly understood. Here, we use solid-state NMR and neutron diffraction to investigate the interactions between a voltage sensor toxin (VSTx1) and lipid membranes, with the goal of localizing the toxin in the membrane and determining its influence on membrane structure. Our results demonstrate that VSTx1 localizes to the headgroup region of lipid membranes and produces a thinning of the bilayer. The toxin orients such that many basic residues are in the aqueous phase, all three Trp residues adopt interfacial positions, and several hydrophobic residues are within the membrane interior. One remarkable feature of this preferred orientation is that the surface of the toxin that mediates binding to voltage sensors is ideally positioned within the lipid bilayer to favor complex formation between the toxin and the voltage sensor.

Sleep deprivation has profound influence on several aspects of health and disease. Mitochondria dysfunction has been implicated to play an essential role in the neuronal cellular damage induced by sleep deprivation, but little is known about how neuronal mitochondrial ultrastructure is affected under sleep deprivation. In this report, we utilized electron cryo-tomography to reconstruct the three-dimensional (3-D) mitochondrial structure and extracted morphometric parameters to quantitatively characterize its reorganizations. Isolated mitochondria from the hippocampus and cerebral cortex of adult male Sprague-Dawley rats after 72 h of paradoxical sleep deprivation (PSD) were reconstructed and analyzed. Statistical analysis of six morphometric parameters specific to the mitochondrial inner membrane topology revealed identical pattern of changes in both the hippocampus and cerebral cortex but with higher significance levels in the hippocampus. The structural differences were indistinguishable by conventional phenotypic methods based on two-dimensional electron microscopy images or 3-D electron tomography reconstructions. Furthermore, to correlate structure alterations with mitochondrial functions, high-resolution respirometry was employed to investigate the effects of PSD on mitochondrial respiration, which showed that PSD significantly suppressed the mitochondrial respiratory capacity of the hippocampus, whereas the isolated mitochondria from the cerebral cortex were less affected. These results demonstrate the capability of the morphometric parameters for quantifying complex structural reorganizations and suggest a correlation between PSD and inner membrane architecture/respiratory functions of the brain mitochondria with variable effects in different brain regions. [ABSTRACT FROM AUTHOR]

Like all structural elements, inflatable beams can be subjected to combined loads. This may be the case for inflatable masts or inflatable columns supporting floors. This study addresses inflatable beams subjected to combinations of compression and bending. Whereas the mechanics of inflatable beams subjected only to transverse loading is now well established, the study of inflatable beams subjected to combined loads has still received few investigation. Furthermore, whereas the effects of individual loads are superimposed when beams are made of conventional materials such as steel, the problem is more complex for inflatable beams since compressive forces counteract the effects of internal pressure and reduce the stiffness. This study presents new analytical formulas for inflatable beams subjected to bending and compressive loads. Buckling load and wrinkling limit load are also proposed, taking into account the internal pressure. [ABSTRACT FROM AUTHOR]

Ceramic membranes are especially beneficial for treating industrial wastewater due to their satisfactory bending strength, high chemical resistance, and excellent thermal stability. However, the high fabrication cost has restricted their wide applications. Usually, sintering-energy consumption accounts for most of the costs of ceramic membranes, thus increasing the fabrication costs and limiting their application prospects. In this review, we discuss strategies to decrease energy consumption and give meaningful prospects for future work. Easily sintered materials, low sintering temperature, cold sintering process, no sintering process, rapid sintering process, and decrease sintering methods (i.e., co-sintering process and optimized membrane structure) are the main methods treated in this work. This review will provide an important reference for ceramic membranes regarding low energy consumption in the ceramic field. [ABSTRACT FROM AUTHOR]

The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures.

EPR spin labeling has been used extensively to study lipids in model membranes to understand their structures and dynamics in biological membranes. The lipid multilamellar liposomes, which are the most commonly used biological membrane model, were prepared using film deposition methods and investigated with the continuous wave EPR technique (T2-sensitive spin-labeling methods). These investigations provided knowledge about the orientation of lipids, their rotational and lateral diffusion, and their rate of flip-flop between bilayer leaflets, as well as profiles of membrane hydrophobicity, and are reviewed in many papers and book chapters. In the early 1980s, the saturation recovery EPR technique was introduced to membrane studies. Numerous T1-sensitive spin-label methods were developed to obtain detailed information about the three-dimensional dynamic membrane structure. T1-sensitive methods are advantageous over T2-sensitive methods because the T1 of spin labels (1–10 μs) is 10 to 1000 times longer than the T2, which allows for studies of membrane dynamics in a longer time–space scale. These investigations used multilamellar liposomes also prepared using the rapid solvent exchange method. Here, we review works in which saturation recovery EPR spin-labeling methods were applied to investigate the properties of multilamellar lipid liposomes, and we discuss their relationships to the properties of lipids in biological membranes.

This review examined a collection of studies regarding the molecular properties of some polyene antibiotic molecules as well as their properties in solution and in particular environmental conditions. We also looked into the proposed mechanism of action of polyenes, where membrane properties play a crucial role. Given the interest in polyene antibiotics as therapeutic agents, we looked into alternative ways of reducing their collateral toxicity, including semi-synthesis of derivatives and new formulations. We follow with studies on the role of membrane structure and, finally, recent developments regarding the most important clinical applications of these compounds.

This paper reports on the manufacturing and evaluation of a solar power sail membrane prototype for the OKEANOS project. The in-house prototype was built by the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency. Mechanical and electrical evaluation tests were conducted. The membrane, thin-film solar cells, reflectivity control devices were good condition after the manufacturing and handling. The improvements in the manufacturing process and design were found. The manufacturing process and design were fundamentally established. After the prototype, improvement plans for the manufacturing process and design were tried. We have a prospect of manufacturing the flight model sail and continue to the development. [ABSTRACT FROM AUTHOR]

A spinning solar sail IKAROS's membrane is estimated to unexpectedly deform into an inverted pyramid shape due to thin-film devices with curvature, such as thin-film solar cells and steering devices on the membrane. It is important to investigate the deformation caused by the curved thin-film devices and predict the sail shape because the out-of-plane deformation greatly affects solar radiation pressure (SRP) and SRP torque. The purpose of this paper is to clarify the relationship between the global shape and orientation and position of curved thin-film devices and to evaluate SRP torque on the global shape using finite element analysis. The global shape is evaluated based on the out-of-plane displacement and the SRP torque. When the curved thin-film devices make the membrane shrink in the circumferential, diagonal, and radial direction, the sail deforms into a pyramid shape, an inverted pyramid one, and a saddle one, respectively. The saddle shape is more desirable for solar sails than the inverted pyramid shape and the pyramid one from the viewpoint of shape stability to SRP and control of SRP torque in the normal direction of the sail (windmill torque). The position of the thin-film device tends to increase the absolute value of windmill torque when it is biased circumferentially from the petal central axis. The suggested design principles for the arrangement of thin-film devices is that the curved thin-film devices should be directed so that the sail shrinks in the radial direction in order to deform the sail into a saddle shape with high shape stability, and the position of the thin-film devices should be biased in the circumferential direction paying attention to the absolute value of windmill torque to determine the direction of windmill torque. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the membrane structure is prone to creases in the process of folding and compaction, a proxy model is used to replace the creases to introduce initial defects for the folded membrane to realize the research of the deployment simulation of the membrane. Based on the finite-element method, the Z-folding and deploying process of the membrane is simulated and the elastic-plastic behavior of the crease is parameterized. The ABAQUS connector is used to replace the crease area of the membrane to simulate the characteristics of the crease and its effectiveness is verified. The deployment of Miura-ori membrane is simulated to explore the influence of force driving and constant-speed driving on the deploying process and deployment results of the membrane. In view of the self-contact phenomenon in the membrane deploying process when driven at a constant-speed, referring to the motion trajectory of the membrane loading corner of the force drive, a step-speed driving method is proposed. The research results show that using a step-speed to drive the deployment of folded membrane can reduce the curvature of the membrane surface, solve the problem of membrane self-contact, and eliminate the phenomenon of stress concentration of membrane surface. In addition, compared with other driving methods, the step-speed driving method has a significant advantage in improving the stability of the deploying process of a membrane. [ABSTRACT FROM AUTHOR]

In this study, dynamic response of a typical umbrella membrane structure under heavy rainfall load is studied by experimental and numerical methods. In the experiment, heavy rainfalls of three rainfall intensities are applied to a typical umbrella membrane structure under five different tensile force levels. The dynamic responses of feature points and tensile force of cables are monitored by laser displacement sensors and digital tensimeters, respectively, during the experiment. In the numerical simulation, the membrane structural model is established in ANSYS by form-finding analysis, and the rainfall load that is calculated by the analytical formula is applied to dynamic analysis. The results of the numerical simulation and the experiment are in good agreement. According to the research results, the dynamic response laws of the umbrella membrane structure under rainstorm were obtained, and the influence of rainstorm load on the umbrella membrane structure was analyzed. Suggestions for safety and structural stability of the membrane structure are proposed. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA) was coated on poly(vinylidene fluoride) (PVDF) membranes with different structures to select the most suitable structure for achieving outstanding hydrophilicity, permeability, stability, and antifouling properties. PVDF membranes were prepared with different solvents (N‐methyl‐2‐pyrrolidone [NMP], N,N‐dimethylacetamide [DMAc], N,N‐dimethylformamide [DMF], NMP/DMAc, NMP/DMF, DMAc/DMF, and NMP/DMAc/DMF), and the factors that influenced the phase inversion were discussed. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) were employed to characterize various membranes. Results indicated that PDA was coated on PVDF membrane surface and formed a smoother PDA layer. Water contact angle measurement confirmed the increased hydrophilicity of PDA modified membranes, but water flux decreased due to the adhesion of PDA on pore walls. The decrease of static adsorption of bovine serum albumin (BSA), the increase of flux recovery ratio (FRR), and the decline of fouling resistance for PDA modified membranes demonstrated that their antifouling properties have been improved significantly. The membrane prepared with NMP/DMAc displayed the highest decay rate of contact angle (16.6 ± 1.27%), the higher water flux (1358.5 ± 33.87 L m−2 h−1), the highest decrease of BSA adsorption (129.3 ± 5.02 μg cm−2), the highest increase rate of BSA rejection (13.6 ± 0.42%), and the highest FRR (92.8 ± 1.42%). This indicated that NMP/DMAc membrane possessed the most suitable structure to improve membrane performances by PDA coating. [ABSTRACT FROM AUTHOR]

A super-pressure balloon with a diamond shaped net is considered to be a vehicle which satisfies scientist requirements of a long duration balloon flight at high altitude. The development of the balloon was started in 2011, and ground inflation tests of scaled models and some flight tests have been performed. In 2016 and 2017, ground inflation tests of two 2,000 m³ balloons, NPB2-1 and NPB2-2, were performed. The meridian lengths and radii of the balloons were measured simultaneously as a function of the differential pressure between inside and outside the balloon to derive their ratio for the first time. Tension along the circumferential direction is resolved in the net balloon, the results show that within the error of a few percent, the ratio is same as that of the pumpkin shape, which withstands the differential pressure only by tension along the meridian direction. The time variation of the differential pressure between inside and outside the balloon was also measured. Based on a simple model, assuming that the balloon volume is a linear function of the differential pressure, the variation of the differential pressure due to the variation of the room temperature and the atmospheric pressure are corrected. Considering the residuals are all due to the gas leakage, the upper limit of a hole size of 0.3 cm² is derived for the NPB2-2 balloon. [ABSTRACT FROM AUTHOR]

Omega-3 FAs EPA and DHA influence membrane fluidity, lipid rafts, and signal transduction. A clinical trial, Reduction of Cardiovascular Events with Icosapent Ethyl—Intervention Trial, demonstrated that high-dose EPA (4 g/d icosapent ethyl) reduced composite cardiovascular events in statin-treated high-risk patients. EPA benefits correlated with on-treatment levels, but similar trials using DHA-containing formulations did not show event reduction. We hypothesized that differences in clinical efficacy of various omega-3 FA preparations could result from differential effects on membrane structure. To test this, we used small-angle X-ray diffraction to compare 1-palmitoyl-2-eicosapentaenoyl-sn-glycero-3-phosphocholine (PL-EPA), 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PL-DHA), and 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PL-AA) in membranes with and without 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol. Electron density profiles (electrons/Å3 vs. Å) were used to determine membrane structure, including membrane width (d-space). PL-EPA and PL-DHA had similar membrane structures without POPC and/or cholesterol but had contrasting effects in the presence of POPC and cholesterol. PL-EPA increased membrane hydrocarbon core electron density over an area of ±0–10 Å from the center, indicating an extended orientation. PL-DHA increased electron density in the phospholipid head group region, concomitant with disordering in the hydrocarbon core and a similar d-space (58 Å). Adding equimolar amounts of PL-EPA and PL-DHA produced changes that were attenuated compared with their separate effects. PL-AA increased electron density centered ±12 Å from the membrane center. The contrasting effects of PL-EPA, PL-DHA, and PL-AA on membrane structure may contribute to differences observed in the biological activities and clinical actions of various omega-3 FAs.

Ruxolitinib is a small-molecule protein kinase inhibitor, which is used as a therapeutic agent against several diseases. Due to its anti-inflammatory impact, ruxolitinib has also been considered recently for usage in the treatment of Covid-19. While the specific effects of ruxolitinib on Janus kinases (JAK) is comparatively well investigated, its (unspecific) impact on membranes has not been studied in detail so far. Therefore, we characterized the interaction of this drug with lipid membranes employing different biophysical approaches. Ruxolitinib incorporates into the glycerol region of lipid membranes causing an increase in disorder of the lipid chains. This binding, however, has only marginal influence on the structure and integrity of membranes as found by leakage and permeation assays.

Glutamate transporters are essential players in glutamatergic neurotransmission in the brain, where they maintain extracellular glutamate below cytotoxic levels and allow for rounds of transmission. The structural bases of their function are well established, particularly within a model archaeal homolog, sodium, and aspartate symporter GltPh. However, the mechanism of gating on the cytoplasmic side of the membrane remains ambiguous. We report Cryo-EM structures of GltPh reconstituted into nanodiscs, including those structurally constrained in the cytoplasm-facing state and either apo, bound to sodium ions only, substrate, or blockers. The structures show that both substrate translocation and release involve movements of the bulky transport domain through the lipid bilayer. They further reveal a novel mode of inhibitor binding and show how solutes release is coupled to protein conformational changes. Finally, we describe how domain movements are associated with the displacement of bound lipids and significant membrane deformations, highlighting the potential regulatory role of the bilayer.

Nanodiscs are membrane mimetics that consist of a protein belt surrounding a lipid bilayer, and are broadly used for characterization of membrane proteins. Here, we investigate the structure, dynamics and biophysical properties of two small nanodiscs, MSP1D1ΔH5 and ΔH4H5. We combine our SAXS and SANS experiments with molecular dynamics simulations and previously obtained NMR and EPR data to derive and validate a conformational ensemble that represents the structure and dynamics of the nanodisc. We find that it displays conformational heterogeneity with various elliptical shapes, and with substantial differences in lipid ordering in the centre and rim of the discs. Together, our results reconcile previous apparently conflicting observations about the shape of nanodiscs, and pave the way for future integrative studies of larger complex systems such as membrane proteins embedded in nanodiscs.

The mitochondrial calcium uniporter is a Ca2+-gated ion channel complex that controls mitochondrial Ca2+ entry and regulates cell metabolism. MCU and EMRE form the channel while Ca2+-dependent regulation is conferred by MICU1 and MICU2 through an enigmatic process. We present a cryo-EM structure of an MCU-EMRE-MICU1-MICU2 holocomplex comprising MCU and EMRE subunits from the beetle Tribolium castaneum in complex with a human MICU1-MICU2 heterodimer at 3.3 Å resolution. With analogy to how neuronal channels are blocked by protein toxins, a uniporter interaction domain on MICU1 binds to a channel receptor site comprising MCU and EMRE subunits to inhibit ion flow under resting Ca2+ conditions. A Ca2+-bound structure of MICU1-MICU2 at 3.1 Å resolution indicates how Ca2+-dependent changes enable dynamic response to cytosolic Ca2+ signals.

Every cell is protected by a semipermeable membrane. Peptides with the right properties, for example Antimicrobial peptides (AMPs), can disrupt this protective barrier by formation of leaky pores. Unfortunately, matching peptide properties with their ability to selectively form pores in bacterial membranes remains elusive. In particular, the proline/glycine kink in helical peptides was reported to both increase and decrease antimicrobial activity. We used computer simulations and fluorescence experiments to show that a kink in helices affects the formation of membrane pores by stabilizing toroidal pores but disrupting barrel-stave pores. The position of the proline/glycine kink in the sequence further controls the specific structure of toroidal pore. Moreover, we demonstrate that two helical peptides can form a kink-like connection with similar behavior as one long helical peptide with a kink. The provided molecular-level insight can be utilized for design and modification of pore-forming antibacterial peptides or toxins.

DNA methylation of the ELOVL2 (Elongation Of Very Long Chain Fatty Acids-Like 2) promoter is one of the most robust molecular biomarkers for chronological age, but whether ELOVL2 plays a functional role in aging has not been explored. ELOVL2 encodes a transmembrane protein involved in the synthesis of very long polyunsaturated fatty acids (VLC-PUFAs). These fatty acids play important roles in retinal biology and photoreceptor renewal, key processes implicated in age-related eye diseases such as age-related macular degeneration (AMD). Here, we summarize our work deciphering the role of ELOVL2 in the eye emphasizing the potential functional role of age-related DNA methylation in the pathophysiology of AMD.