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Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective This study investigated the efficacy of different concentrations of cholesterol-loaded cyclodextrin (CLC) on cryopreservation in boar sperm quality. Methods In this study, we treated boar sperm with different concentrations of CLC before freezing and analyzed the sperm cholesterol concentration, plasma membrane, acrosome integrity rate and total motility rate before and after freeze-thawing. We also investigated the levels of reactive oxygen species (ROS), malondialdehyde (MDA), adenosine triphosphate (ATP), and structural- and oxidative-damage related proteins in all groups after thawing. Results The results revealed that the cholesterol concentration of the CLC-treated groups was higher than that of the control group, both before freezing and after thawing (p

Antimicrobial peptide (AMP) surfaces are widely used to inhibit biofilm formation and bacterial infection. However, endpoint-immobilized AMPs on surfaces are totally different from free-state AMPs due to the constraints of the surface. In this work, the interactions between AMPs and bacterial cell membranes were analyzed through coarse-grained molecular dynamics and all-atom molecular dynamics simulations. This AMP disrupted membrane structure by altering the thickness and curvature of the membrane. Furthermore, the effect of surface-immobilized states of AMPs on their ability to disrupt membrane structure was revealed. The immobilized AMPs in the freeze-N system could bind to the membrane and disrupt the membrane structure through electrostatic forces between positively charged N-terminal amino acid residues and the negatively charged membrane, while the immobilized AMPs in the freeze-C system were repelled. The results will aid in the rational design of new AMP surfaces with enhanced efficacy and stability. [ABSTRACT FROM AUTHOR]

The mechanical properties of ETFE foils after aging in natural environment are the basis for long-term performance evaluation of ETFE structures. In this paper, the aging ETFE foils were selected to carry out the micro-morphology experiments and macro-mechanical tests. The standard values of mechanical parameters were analyzed based on statistical methods. The micro results show that the rough surface morphology and dense cross-section wrinkles existed and that the grain size increased by 7.8%. The breaking strength, yield stress and elastic modulus of aging ETFE foils decreased significantly. The standard values of the yield stress and elastic modulus were 11.73 MPa and 703.2 MPa, which reduced by 14.9% and 13.5%. In general, these results are critical for accurately evaluating long-term performance of ETFE structures. [ABSTRACT FROM AUTHOR]

The fact that tension fabric structures are light and durable, as well as visually pleasing, has become a reason for preference, especially in contemporary architecture. In this article, in addition to a comprehensive evaluation of stretchable fabric structures, two important stretchable fabric systems, Bigo Arena and Denver International Airport, are used as case studies. By comparing these two case studies, this study pays attention to the differences and properties of the materials while also emphasizing the advantages of the tensile fabric structure. It aims to give ideas to researchers working on this subject by researching the materials and techniques used during construction and examining the possibilities, such as their impact on progress and sustainability in architecture. The Denver International Airport and Bigo Arena serve as prime examples of how membrane systems may be used successfully in architectural projects. While PTFE-coated glass fiber material is preferred in the construction of lightweight structures, it also provides the opportunity to capture solar radiation. Through the projects examined in this research, it is emphasized that fiberglass material coated with PTFE is an example of how interior spaces can be more useful by creating both aesthetic and well-lit spaces. In summary, the case studies demonstrate the successful application of membrane frameworks to achieve functional and aesthetically acceptable goals in architecture.

Nonsolvent-induced phase separation is a widely used technique in the manufacture of polymeric separators. This method involves fine-tuning porous structures through the phase separation of polymer solutions in Li-ion secondary battery systems. The phase separation properties and kinetics of heat-resistant poly(vinylidene fluoride-co-hexafluoropropylene) polymer solutions were characterized by adjusting the weight ratio of N-methyl-2-pyrrolidone (NMP) as a solvent and water as a nonsolvent using both macro- and micro-rheological techniques. The viscoelastic moduli, measured with a rotational rheometer as a macro-rheological technique, and autocorrelation functions describing the fast movements of tracer ceria particles within polymer solutions—quickly detected using the micro-rheological light scattering technique of multi-speckle diffusing wave spectroscopy—offered a comprehensive assessment of the phase separation status and its kinetics during changes in the NMP/water ratio. These results are expected to play a fundamental role in understanding and controlling the pore structures of actual separator membranes applied in Li-ion battery systems. [ABSTRACT FROM AUTHOR]

A nano-satellite called the re-entry satellite with a gossamer aeroshell and GPS/Iridium (EGG) was developed as part of the research and development of a re-entry system featuring a deployable membrane aeroshell. The EGG has a size of 3U (11 cm × 11 cm × 34 cm, 4 kg) including the packed membrane aeroshell. This membrane aeroshell consists of an inflatable ring and a membrane flare and can be deployed using a gas injection system installed in the EGG’s main body. The diameter of the deployed aeroshell is 80 cm. The EGG was deployed from the ISS by the JEM Small Satellite Orbital Deployer (J-SSOD) in January 2017. The aeroshell deployment sequence was successfully executed in February 2017. Images of the deployed aeroshell were captured by onboard cameras. After the deployment of the aeroshell, the EGG gradually lost altitude owing to the aerodynamic force acting on the aeroshell. This trend of orbital decay was confirmed by the GPS data. All flight data right until re-entry were acquired via the Iridium satellite network. Therefore, the EGG became the first satellite to rely solely on the Iridium satellite network for telemetry and command. [ABSTRACT FROM AUTHOR]

We describe how to use several machine learning techniques organized in a learning pipeline to segment and identify cell membrane structures from cryo electron tomograms. These tomograms are difficult to analyze with traditional segmentation tools. The learning pipeline in our approach starts from supervised learning via a special convolutional neural network trained with simulated data. It continues with semi-supervised reinforcement learning and/or a region merging technique that tries to piece together disconnected components belonging to the same membrane structure. A parametric or non-parametric fitting procedure is then used to enhance the segmentation results and quantify uncertainties in the fitting. Domain knowledge is used in generating the training data for the neural network and in guiding the fitting procedure through the use of appropriately chosen priors and constraints. We demonstrate that the approach proposed here works well for extracting membrane surfaces in two real tomogram datasets.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims This study aimed to investigate the changes of cell membrane structure and function of Issatchenkia terricola under citric acid by performing physiological analysis. Methods and results The membrane integrity, surface hydrophobicity, structure, fluidity, apoptosis, and fatty acid methyl esters composition of I. terricola WJL-G4 cells were determined by propidium iodide staining, microbial adhesion to hydrocarbon test, transmission electron microscopy analysis, fluorescence anisotropy, flow cytometry, and gas chromatography-mass, respectively. The results showed that with the increasing of citric acid concentrations, the cell vitality, membrane integrity, and fluidity of I. terricola reduced; meanwhile, apoptosis rate, membrane permeable, hydrophobicity, and ergosterol contents augmented significantly. Compared to control, the activities of Na+, K+-ATPase, and Ca2+, Mg2+-ATPase increased by 3.73-fold and 6.70-fold, respectively, when citric acid concentration increased to 20 g l−1. The cells cracked and their cytoplasm effused when the citric acid concentration reached 80 g l−1. Conclusions I. terricola could successfully adjust its membrane structure and function below 60 g l−1 of citric acid. However, for citric acid concentrations above 80 g l−1, its structure and function were dramatically changed, which might result in reduced functionality. [ABSTRACT FROM AUTHOR]

Although various studies on vibration control schemes exist, most of them focus on a one-time optimization of actuator layout. However, numerical results indicate significant drawbacks of fixed layouts on control performance, a factor rarely mentioned in the field of vibration control. This study aims to address this gap by proposing a novel rearrangement strategy that adaptively varies the actuator layout based on the vibration intensity pattern. The inspiration for this approach comes from the reorientation of cortical microtubules in plant cells, which adapt to stress patterns. The study first derives the definitions of vibration patterns and the index of intensity based on energy transfer. These definitions then guide the optimization of actuator layout throughout the control process. The study compares the fixed layout with the proposed adaptive varying layout, considering both full-state feedback and recognition feedback. The numerical results demonstrate that the proposed adaptive rearrangement of actuator layout significantly improves suppression performance, leading to higher utilization efficiency of control forces. Additionally, the presented strategy is tolerant to computation errors from recognition feedback, resulting in robust enhancements in vibration attenuation. Our study has introduced new possibilities for improving existing control schemes. • First-time practical dynamic rearrangement strategy adapts actuator layout based on system responses. • A bioinspired optimization framework aligns the actuator layout with a vibration intensity pattern in a fast-computing manner. • The strategy is compatible with both full-state feedback and recognition reconstructed from sensing signals. • Simulations show improved control performance with increased force utilization and error tolerance. [ABSTRACT FROM AUTHOR]

The organelles of eukaryotic cells maintain distinct protein and lipid compositions required for their specific functions. The mechanisms by which many of these components are sorted to their specific locations remain unknown. While some motifs mediating subcellular protein localization have been identified, many membrane proteins and most membrane lipids lack known sorting determinants. A putative mechanism for sorting of membrane components is based on membrane domains known as lipid rafts, which are laterally segregated nanoscopic assemblies of specific lipids and proteins. To assess the role of such domains in the secretory pathway, we applied a robust tool for synchronized secretory protein traffic (RUSH, Retention Using Selective Hooks) to protein constructs with defined affinity for raft phases. These constructs consist solely of single-pass transmembrane domains (TMDs) and, lacking other sorting determinants, constitute probes for membrane domain-mediated trafficking. We find that while raft affinity can be sufficient for steady-state PM localization, it is not sufficient for rapid exit from the endoplasmic reticulum (ER), which is instead mediated by a short cytosolic peptide motif. In contrast, we find that Golgi exit kinetics are highly dependent on raft affinity, with raft preferring probes exiting the Golgi ~2.5-fold faster than probes with minimal raft affinity. We rationalize these observations with a kinetic model of secretory trafficking, wherein Golgi export can be facilitated by protein association with raft domains. These observations support a role for raft-like membrane domains in the secretory pathway and establish an experimental paradigm for dissecting its underlying machinery.

Research on porous membrane technology is proliferating, especially in the process of fabrication of membranes. Different methods in membrane fabrication can affect the physical and chemical properties of the produced membrane. This study aims to investigate the influence of temperature, molecular weight, and non-solvent type on the physical-chemical properties of PVDF membranes. The membrane was produced by the immersion precipitation method with varying PVDF molecular weights of 64 kDa, 352 kDa (Solef 1010), 534 kDa, and 573 kDa (Solef 1015); non-solvent variations of alcohol (methanol, ethanol, isopropyl alcohol, and butanol); and drying temperature variations of 40, 50, and 60°C. The produced membranes were analyzed using ATR-FTIR, XRD, TGA, DSC, and SEM, and their wettability properties were evaluated using water contact angles. The optimal drying temperature for membrane production was 60°C. The ATR-FTIR data showed that molecular weight impacted membrane structure, where PVDF MW 534 kDa membrane had the highest percentage of β phase (77.47%). Non-solvent changes also affected membrane structure; PVDF Solef 1010 with non-solvent isopropyl alcohol had the highest percentage of β phase (67.45%). This is supported by the XRD diffractogram that displayed peaks at 2θ values between 20.24° and 20.66°, indicating the presence of a phase β PVDF. The thermal analysis exhibited three stages of degradation for Solef 1010 with ethanol non-solvent and two for the other seven membranes. The degradation temperature increases with the increase in molecular weight and the difference in non-solvents. The highest thermal stability membrane was PVDF Solef 1010 with isopropyl alcohol non-solvent (430°C). SEM images showed the membrane with non-solvent isopropyl alcohol, displaying a dense sponge-like morphology. The wettability of membranes is affected by molecular weight and non-solvent type. The membrane with isopropyl alcohol non-solvent obtained the smallest contact angle (54.77°) and indicated the most wettability membrane.

Antimicrobial peptide (AMP) surfaces are widely used to inhibit biofilm formation and bacterial infection. However, endpoint-immobilized AMPs on surfaces are totally different from free-state AMPs due to the constraints of the surface. In this work, the interactions between AMPs and bacterial cell membranes were analyzed through coarse-grained molecular dynamics and all-atom molecular dynamics simulations. This AMP disrupted membrane structure by altering the thickness and curvature of the membrane. Furthermore, the effect of surface-immobilized states of AMPs on their ability to disrupt membrane structure was revealed. The immobilized AMPs in the freeze-N system could bind to the membrane and disrupt the membrane structure through electrostatic forces between positively charged N-terminal amino acid residues and the negatively charged membrane, while the immobilized AMPs in the freeze-C system were repelled. The results will aid in the rational design of new AMP surfaces with enhanced efficacy and stability.

Rice sheath blight is a fungal disease caused mainly by Rhizoctonia solani AG1-IA. Toxins are a major pathogenic factor of R. solani, and some studies have reported their toxin components; however, there is no unified conclusion. In this study, we reported the toxin components and their targets that play a role in R. solani AG1-IA. First, toxins produced by R. solani AG1-IA were examined. Several important phytotoxins, including benzoic acid (BZA), 5-hydroxymethyl-2-furanic aid (HFA), and catechol (CAT), were identified by comparative analysis of secondary metabolites from AG1-IA, AG1-IB, and healthy rice. Follow-up studies have shown that the toxin components of this fungus can rapidly disintegrate the biofilm structure while maintaining the content of host plant membrane components, thereby affecting the organelles, which may also explain the lack of varieties highly resistant to sheath blight. [ABSTRACT FROM AUTHOR]

Research on porous membrane technology is proliferating, especially in the process of fabrication of membranes. Different methods in membrane fabrication can affect the physical and chemical properties of the produced membrane. This study aims to investigate the influence of temperature, molecular weight, and non-solvent type on the physical-chemical properties of PVDF membranes. The membrane was produced by the immersion precipitation method with varying PVDF molecular weights of 64 kDa, 352 kDa (Solef 1010), 534 kDa, and 573 kDa (Solef 1015); non-solvent variations of alcohol (methanol, ethanol, isopropyl alcohol, and butanol); and drying temperature variations of 40, 50, and 60°C. The produced membranes were analyzed using ATR-FTIR, XRD, TGA, DSC, and SEM, and their wettability properties were evaluated using water contact angles. The optimal drying temperature for membrane production was 60°C. The ATR-FTIR data showed that molecular weight impacted membrane structure, where PVDF MW 534 kDa membrane had the highest percentage of ß phase (77.47%). Nonsolvent changes also affected membrane structure; PVDF Solef 1010 with nonsolvent isopropyl alcohol had the highest percentage of β phase (67.45%). This is supported by the XRD diffractogram that displayed peaks at 2° values between 20.24° and 20.66°, indicating the presence of a phase β PVDF. The thermal analysis exhibited three stages of degradation for Solef 1010 with ethanol nonsolvent and two for the other seven membranes. The degradation temperature increases with the increase in molecular weight and the difference in nonsolvents. The highest thermal stability membrane was PVDF Solef 1010 with isopropyl alcohol non-solvent (430°C). SEM images showed the membrane with non-solvent isopropyl alcohol, displaying a dense sponge-like morphology. The wettability of membranes is affected by molecular weight and non-solvent type. The membrane with isopropyl alcohol non-solvent obtained the smallest contact angle (54.77°) and indicated the most wettability membrane. [ABSTRACT FROM AUTHOR]

The dynamic of hypervelocity projectile impacting inflatable multilayer flexible membrane structure is studied in this paper. The velocity increment of the inflatable multilayer flexible membrane structure under hypervelocity impact comes from two parts. One is the acceleration caused by the pulling of the membrane when the hypervelocity projectile is in direct contact with the membrane, and the other is the acceleration provided by the reverse impulse caused by the gas leakage in the inflatable structure. The hypervelocity projectile will be decelerated in the impact process, and finally fly with the accelerated multilayer flexible membrane structure at the same velocity, which means that the projectile is captured by the membrane structure. According to the above process, the influence of the mechanical property parameters of the flexible membrane on the structural parameters of the multi-layer flexible membrane can be calculated, which can be used to guide the engineering design. Finally, the hypervelocity impact process is verified by the numerical simulation. • Space soft capture method achieved through flexible inflatable membrane structure. • Hypervelocity impact dynamics of flexible inflatable membrane structure. • Verify the dynamic process of hypervelocity impact using numerical simulation. • The influence of membrane mechanical properties on the parameters of the structure. [ABSTRACT FROM AUTHOR]

Within the food industry, membrane separation is commonplace due to its relatively low energy consumption. It allows fractionation of various feeds (e.g., milk) into starting materials for food design. We feel that considerable progress can still be made. For this, the specific properties of the components of interest would need to be taken into account, such as their mobility in flow, and their deformability in relation to the actual membrane structure. Furthermore, improvements are possible through cascaded use of membrane processes, and upgrading waste streams, which leads to new opportunities. [ABSTRACT FROM AUTHOR]

The existing large inflatable membrane structure is complex in structure and takes a long time to be extended. In this paper, an air-ribbed skeleton membrane structure is proposed to meet the requirement of camp and emergency tents needing to be set up quickly and easily. Ten single-arch air ribs are arranged side by side to support the tarpaulin, and wind ropes are added to the end and side faces of the tarpaulin to remain stable. The finite element model of the air-ribbed skeleton membrane structure is established to analyze the stress and the displacement of the membrane structure under combined wind and snow loads. The maximum displacement (439.4 mm) and maximum stress (29.94 MPa) are both within the safe standard. The stress and the displacement of the membrane structure in the wind load case is affected by the angle of the wind. The value of maximum stress and displacement at the wind angle of 90° are both lower than those at 0° and 45° in the wind load case. It is advisable to align the site layout of the membrane structure at the wind angle of 90°. The effect of the angle of wind ropes on the stress and displacement of the membrane structure is also studied. The maximum stress and displacement in the case when the angle of wind rope is 30° is smaller than those in the case when the angle of wind ropes is 45°. It is recommended that the wind rope should be laid at 30° to reinforce the membrane structure. [ABSTRACT FROM AUTHOR]

Lipids constitute a significant group of biological metabolites and the building blocks of all cell membranes. The abundance and stoichiometries of different lipid species are known to vary across the lifespan and metabolic state, yet the functional effects of these changes have been challenging to understand. Here we review the potentially powerful intersection of lipid metabolism, which determines membrane composition, and aging. We first introduce several key lipid classes that are associated with aging and aging-related disease, where they are found in organisms, and how they act on membrane structure and function. Instead of neutral lipids, which have primary roles in energy storage and homeostasis, we review known functions for polar lipids that control the physicochemical properties of cell membranes. We then focus on aging processes in the central nervous system (CNS), which is enriched in lipids and is highly dependent on membrane structure for function. Recent studies show how lipids act not just as biomarkers of aging and associated changes in the CNS, but as direct mediators of these processes. As a model system, we explore how fatty acid composition in the retina impact aging and aging-related disease. We propose that the biophysical effects of membrane structure on fundamental eukaryotic processes - mitochondrial respiration and autophagy - provide avenues by which lipid dysregulation can accelerate aging processes. Finally, we lay out ways in which an increased understanding of lipid membrane biology can be applied to studies of aging and lifespan.

Introduction: Antifreeze peptides regulate the physiological functions of frozen cells and even their apoptosis; however, the mechanisms by which antifreeze peptides regulate these processes remain unclear, although the interactions between cell membranes and ice are well known to be important in this process. Objectives: Our study aims to investigate how antifreeze peptides regulate cell physiological functions during the freezing process. Methods: We investigated the cryoprotective effect of rsfAFP on the physiological functions of S. thermophilus under freezing stress by measuring cellular metabolism activity, intracellular enzyme activity, cell membrane characterization, and cell apoptosis. The mechanism by which rsfAFP impacts S. thermophilus physiological functions under freezing stress was investigated using multispectral techniques and cryo-TEM. Results: We show that a recombinant antifreeze peptide (rsfAFP) interacts with the extracellular capsular polysaccharides and peptidoglycan of Streptococcus thermophilus and ice to cover the outer layer of the membrane, forming a dense protective layer that regulates the molecular structure of extracellular ice crystals, which results in reduced extracellular membrane damage, depressed apoptosis and increased intracellular metabolic activity. This interaction mechanism was indicated by the fact that S. thermophilus better maintained its permeability barrier, membrane fluidity, membrane structural integrity, and cytoplasmic membrane potential during freezing stress with rsfAFP treatment. Conclusion: These results provide new insights into the mechanism by which rsfAFP regulates frozen cell physiological functions and apoptosis under freezing stress.

The membrane structure roof is widely used in large-span buildings such as stadiums and gymnasiums because of its full use of natural light sources and flexible forms. In order to solve the prominent problems such as poor thermal insulation performance and prone to external environmental factors, the multi-layer membrane structure design, laying of insulation layers, and other schemes are applied to engineering practice. However, there is still a gap in the relevant research of thermal environment monitoring and analysis. In order to study the thermal environment of the double-layer PTFE (polytetrafluoroethylene)-aerogel roof, multi-point thermometers were uniformly arranged to monitor, and the overall temperature field was constructed using the measured data. A thermophysical model which could accurately reflect the change of temperature field was established, whose average error was less than 5%. With the laying of roof insulation layer as the variable, three working conditions, i.e., no insulation layer, only rock wool insulation layer, and all aerogel insulation layer were constructed based on the model. The comparison indicates that the laying of aerogel reduces the average temperature of indoor space by 2.0 ℃, the original working condition has the best thermal insulation effect, and the average temperature difference between indoor and outdoor is 9.6 ℃. This paper can provide reference for the thermal insulation design of membrane structure roofs.

When encountering heavy rain, the membrane surface with a relatively small slope is easy to accumulate water. Accurately simulating the deformation of the membrane surface at this time will help ensure the safety of the structure. The linear constitutive model of membrane material used in existing research is not suitable for simulating the deformation of membrane structure in rainstorm. This study conducts a uniform load test on a membrane structure to simulate the mechanical behavior of the membrane surface in rainstorm and obtains the deformation form of the structure when water is accumulated. The linear constitutive model and the double broken line constitutive model of membrane material are used in the finite element model of the membrane structure for load analysis. By comparing the deformation of the finite element model and the actual structure, it selects the constitutive model suitable for simulating the deformation of the membrane structure in heavy rain. The numerical simulation results show that the structural deformation simulated by the double broken line constitutive model is closer to the deformation measured in the experiment than the linear constitutive model. The research results can provide a reference for the selection of the membrane constitutive model and the analysis of membrane structure in rainstorm.

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.

The design of suitable and efficient membranes for fuel and electrolyzer cells has been a long standing problem that still seeks for technical improvements. The structural properties of proton conducting poly [2,2-(m-phenylene)-5,5-bibenzimidazole] (PBI) membranes doped with phosphoric acid as electrolyte have been investigated prior and after thermal treatment by small angle neutron scattering (SANS), neutron diffraction with polarization analysis and transmission electron microscopy (TEM). Our observations indicate that during the first heating attempt stable crystalline domains in the PBI are formed and they persist in all further thermal cycles typical for electrolyte membrane operation. The combination of real space TEM picture under cryogenic conditions and reciprocal space scattering pattern with enhanced contrast by partial deuteration allows obtaining unique insight into the structure of proton conducting membranes, i.e., characteristic distances associated with irreversible changes as well as volume fraction of the different phases of the sample.

The author first describes his childhood in the South and the ways in which it fostered the values he has espoused throughout his life, his development of a keen fascination with science, and the influences that supported his progress toward higher education. His experiences in ROTC as a student, followed by two years in the US Army during the Vietnam War, honed his leadership skills. The bulk of the autobiography is a chronological journey through his scientific career, beginning with arrival at the University of California, Irvine in 1972, with an emphasis on the postdoctoral students and colleagues who have contributed substantially to each phase of his lab's progress. White's fundamental findings played a key role in the development of membrane biophysics, helping establish it as fertile ground for research. A story gradually unfolds that reveals the deeply collaborative and painstakingly executed work necessary for a successful career in science. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study provides new insights into the mechanism by which antifreeze peptides regulate cell physiological functions and apoptosis under freezing stress. • A novel interaction model between frozen cells and ice crystals with antifreeze peptide intervention was revealed. • This study provides a scientific basis for the use of an antifreeze peptide as an effective cryopreservation agent for LAB and other microbes. Antifreeze peptides regulate the physiological functions of frozen cells and even their apoptosis; however, the mechanisms by which antifreeze peptides regulate these processes remain unclear, although the interactions between cell membranes and ice are well known to be important in this process. Our study aims to investigate how antifreeze peptides regulate cell physiological functions during the freezing process. We investigated the cryoprotective effect of rsfAFP on the physiological functions of S. thermophilus under freezing stress by measuring cellular metabolism activity, intracellular enzyme activity, cell membrane characterization, and cell apoptosis. The mechanism by which rsfAFP impacts S. thermophilus physiological functions under freezing stress was investigated using multispectral techniques and cryo-TEM. We show that a recombinant antifreeze peptide (rsfAFP) interacts with the extracellular capsular polysaccharides and peptidoglycan of Streptococcus thermophilus and ice to cover the outer layer of the membrane, forming a dense protective layer that regulates the molecular structure of extracellular ice crystals, which results in reduced extracellular membrane damage, depressed apoptosis and increased intracellular metabolic activity. This interaction mechanism was indicated by the fact that S. thermophilus better maintained its permeability barrier, membrane fluidity, membrane structural integrity, and cytoplasmic membrane potential during freezing stress with rsfAFP treatment. These results provide new insights into the mechanism by which rsfAFP regulates frozen cell physiological functions and apoptosis under freezing stress. [ABSTRACT FROM AUTHOR]

• A unified novelty procedure is proposed to study the sound radiation and sound transmission performance from the membrane backed by a variable-shape cavity based on the energy principle. The proposed model can directly calculate acoustic quantities such as sound radiation and sound intensity. • The back irregular acoustic cavity is regularized by coordinate transformation theory, which is simple and efficient for acoustic quantity calculation and multi-physics coupling analysis. • A detailed study was conducted on the effects of various parameters on the sound radiation power and sound transmission loss of the coupled system. • This paper analyzes the membrane structures from the perspectives of analytical modeling, finite element method simulation, and experiment respectively. The drum-type muffler comprises a rigid back cavity and a tensioned membrane, which utilizes the radiation sound field of a membrane and the superposition effect of the enclosed sound field to achieve noise reduction. However, most previous studies have been focused on idealized models, with little research on the sound radiation power from a membrane concerning a variable-shape back cavity. This article aims to establish a membrane vibration-acoustic model and investigate the impact of irregular shape and pre-tension conditions on the radiated sound energy. The microunits on the surface of the membrane and the pressure of the sound field are represented as cosine Fourier series. The variable-shape cavity is converted into a normal one by employing the coordinate transformation method. The analytical model of the coupling structure composed by a membrane and the enclosed sound fields is developed based on the energy principle. The acoustic and vibration characteristics of the membrane are solved based on the Rayleigh integral equation. This study also considers the difference in sound insulation performance between the thin plate and the membrane. The analytical results are compared with Finite Element Analysis (FEM) to verify the correctness of the theoretical model. In addition, based on the LMS Simcenter measurement system, experiments are designed to predict the sound pressure on both sides of the membrane. The test results closely correspond with the theoretical calculation results, which confirms the practicality of the theoretical approach. [ABSTRACT FROM AUTHOR]

As the world confronts the pursuit of sustainable energy sources, floating photovoltaic (FPV) systems emerge as a focal point of innovation. As a novel FPV system, the membrane structure, owing to its advantages of lightweight design and economic feasibility, presents significant potential for widespread applications. Drawing inspiration from Ocean Sun's membrane prototype, this article devised a research model for the membrane structure. The initial phase involved a frequency-domain study. A 1:40 scale-down model was meticulously crafted for laboratory experiments, intended for comparison with numerical simulations. Conclusively, the amplitude response functions of the experimental scaled model aligned well with those of the numerically simulated scaled model and full-scale model. Moving forward, a time-domain study was conducted through numerical simulations to analyze the hydrodynamic responses of the prototype under combined wave and current loading. The findings revealed that the membrane structure have good seakeeping and stability. In comparison to the working sea state, the structural motion responses and mooring forces under survival sea state were significantly amplified. Notably, the mooring forces exhibited the most pronounced increase, surpassing a two-fold relationship. Subsequently, comparative analyses were conducted between membrane structures and FPV platforms in six relevant studies. It was found that the trends in RAO and wave interactions exhibited by these structures generally align with those observed in membrane structures. • The experiments to scrutinize the motion responses under varying wave periods. • A time-domain study to analyze the hydrodynamic responses of the prototype. • The mooring forces exhibited the most pronounced increase, surpassing a two-fold relationship. [ABSTRACT FROM AUTHOR]

Due to their lightness, the capacity to adapt to the flow conditions, and the safety when operating near humans, the use of membrane-resistant structures has increased in fields as micro aerial vehicles and yachts sails. This work focuses on the computational methodology required for simulating the aeroelastic coupling of the structure with the incident wind flow. A semi-monocoque structure (composed of a main spar, a set of ribs, and an external membrane) inside a wind tunnel is simulated using two different methodologies. Firstly, a complete fluid-structure interaction is calculated by combining the finite element methodology for the solid and the unsteady Reynolds average Navier-Stokes computational fluid dynamics for the air, including nonlinear effects and prestress. Then, a low-fidelity model is applied, obtaining the linear aeroelastic eigenvalues and the temporal response of the wing. Both methodologies results are in agreement with estimating the transient mean deformation and flutter velocity. However, the modal analysis tends to overestimate the aeroelastic effects, as it calculates potential aerodynamics, predicting an instability velocity lower than that provided by the transient simulations. • Development and validation of a low-fidelity model for aeroelastic simulation of flexible membrane wings. • Analysis of the shell behavior of the membrane and limitations of the low-fidelity model. • Analysis of the effects of prestressing the membrane. • Prediction of aeroelastic instabilities through the low-fidelity model. • Analysis of the interaction between the membrane distortion and the aeroelastic behavior of the wing. [ABSTRACT FROM AUTHOR]

Membrane technology plays a vital role in drinking water and wastewater treatments. Among a number of factors affecting membrane performance, temperature is one of the dominant factors determining membrane performance. In this review, the impact of temperature on membrane structure, fouling, chemical cleaning, and membrane performance is reviewed and discussed with a particular focus on cold temperature effects. The findings from the literature suggest that cold temperatures have detrimental impacts on membrane structure, fouling, and chemical cleaning, and thus could negatively affect membrane filtration operations and performance, while warm and hot temperatures might expand membrane pores, increase membrane flux, improve membrane chemical cleaning efficiency, and interfere with biological processes in membrane bioreactors. The research gaps, challenges, and directions of temperature effects are identified and discussed indepth. Future studies focusing on the impact of temperature on membrane processes used in water and wastewater treatment and the development of methods that could reduce the adverse effect of temperature on membrane operations are needed.

The effect of the antioxidant resveratrol on the structure of mitochondrial membranes isolated from Pisum sativum L. pea germ exposed to a heat stress factor is studied. The temperature dependence of microviscosity is used as the structural characteristics of the membranes. The microviscosity is determined by the method of electron spin resonance (ESR). Heat stress leads to a decrease in the crystallinity of mitochondrial membranes. It is shown that ultralow doses (ULDs) of resveratrol restore the structure of the lipid bilayer of the mitochondria after exposure to heat stress (HS) to a state similar to intact plants. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wave-based active vibration control of a membrane structure by using the Active Sink Method is studied in this paper. Unlike the modal-based vibration control method which attempts to suppress several vibration modes that have already been excited, wave-based active controller can keep vibration modes inactive by stopping the formation of standing waves in the structure. First, the wave transfer matrix is deduced to characterize the wave transmission in the membrane structure. Then, feedforward wave control laws are derived analytically to absorb reflected waves or eliminate transmitted waves. The validity of the proposed active wave controllers is verified through numerical simulations. Simulation results show that by using the active wave controllers no standing waves will be produced in the structure, and the vibration of the membrane structure is suppressed significantly. [ABSTRACT FROM AUTHOR]

Membranes are molecular interfaces that compartmentalize cells to control the flow of nutrients and information. These functions are facilitated by diverse collections of lipids, nearly all of which are distributed asymmetrically between the two bilayer leaflets. Most models of biomembrane structure and function often include the implicit assumption that these leaflets have similar abundances of phospholipids. Here, we show that this assumption is generally invalid and investigate the consequences of lipid abundance imbalances in mammalian plasma membranes (PM). Using quantitative lipidomics, we discovered that cytoplasmic leaflets of human erythrocyte membranes have >50% overabundance of phospholipids compared to exoplasmic leaflets. This imbalance is enabled by an asymmetric interleaflet distribution of cholesterol, which regulates cellular cholesterol homeostasis. These features produce unique functional characteristics, including low PM permeability and resting tension in the cytoplasmic leaflet that regulates protein localization. These largely overlooked aspects of membrane asymmetry represent an evolution of classic paradigms of biomembrane structure and physiology., Competing Interests: Declaration of interests: The authors declare no competing interests.

Myelin is a natural and dynamic multilamellar membrane structure that continues to be of significant biological and neurological interest, especially with respect to its biosynthesis and assembly during its normal formation, maintenance, and pathological breakdown. To explore the usefulness of neutron diffraction in the structural analysis of myelin, we investigated the use of in vivo labeling by metabolically incorporating non-toxic levels of deuterium (2H; D) via drinking water into a pregnant dam (D-dam) and her developing embryos. All of the mice were sacrificed when the pups (D-pups) were 55 days old. Myelinated sciatic nerves were dissected, fixed in glutaraldehyde and examined by neutron diffraction. Parallel samples that were unfixed (trigeminal nerves) were frozen for mass spectrometry (MS). The diffraction patterns of the nerves from deuterium-fed mice (D-mice) vs. the controls (H-mice) had major differences in the intensities of the Bragg peaks but no appreciable differences in myelin periodicity. Neutron scattering density profiles showed an appreciable increase in density at the center of the lipid-rich membrane bilayer. This increase was greater in D-pups than in D-dam, and its localization was consistent with deuteration of lipid hydrocarbon, which predominates over transmembrane protein in myelin. MS analysis of the lipids isolated from the trigeminal nerves demonstrated that in the pups the percentage of lipids that had one or more deuterium atoms was uniformly high across lipid species (97.6% ​± ​2.0%), whereas in the mother the lipids were substantially less deuterated (60.6% ​± ​26.4%) with levels varying among lipid species and subspecies. The mass distribution pattern of deuterium-containing isotopologues indicated the fraction (in %) of each lipid (sub-)species having one or more deuteriums incorporated: in the D-pups, the pattern was always bell-shaped, and the average number of D atoms ranged from a low of ∼4 in fatty acid to a high of ∼9 in cerebroside. By contrast, in D-dam most lipids had more complex, overlapping distributions that were weighted toward a lower average number of deuteriums, which ranged from a low of ∼3–4 in fatty acid and in one species of sulfatide to a high of 6–7 in cerebroside and sphingomyelin. The consistently high level of deuteration in D-pups can be attributed to their de novo lipogenesis during gestation and rapid, postnatal myelination. The widely varying levels of deuteration in D-dam, by contrast, likely depends on the relative metabolic stability of the particular lipid species during myelin maintenance. Our current findings demonstrate that stably-incorporated D label can be detected and localized using neutron diffraction in a complex tissue such as myelin; and moreover, that MS can be used to screen a broad range of deuterated lipid species to monitor differential rates of lipid turnover. In addition to helping to develop a comprehensive understanding of the de novo synthesis and turnover of specific lipids in normal and abnormal myelin, our results also suggest application to studies on myelin proteins (which constitute only 20–30% by dry mass of the myelin, vs. 70–80% for lipid), as well as more broadly to the molecular constituents of other biological tissues.

Rotenone is a widely used botanical insecticide, which can inhibit the mitochondrial respiratory chain of various insect cells, while the mechanism of its toxicity to insect cells needs further investigation. The purpose of this study was to understand the toxicity level of low (0.2 µg/mL) and high (20 µg/mL) concentrations of rotenone in Spodoptera litura cells (SL-1) using trypan blue and Coomassie brilliant blue staining assays. Our study found that rotenone possessed cytotoxicity against SL-1 cells with varying effects of action between high and low concentrations. After low-concentration rotenone treatment, the SL-1 cells showed obvious aggregation time-dependently, with the fastest aggregation rate observed under the first 8 h of treatment time, but no such phenomenon was observed at high concentration. Furthermore, this aggregation phenomenon caused SL-1 cells to squeeze each other and led to the destruction of the cell membrane structure and function. Taken together, the results suggested that treatment with a low concentration of rotenone exhibited a chronic toxic effect that was significantly different from treatment with a high concentration of rotenone, which provides new insight into the cytotoxic mechanism of rotenone. [ABSTRACT FROM AUTHOR]

The pretension of building membrane structures may relax over its service lifetime, which may cause engineering failure under external loads. Therefore, the pretension of building membrane structures should be monitored or estimated regularly to compare the actual pretension to its design pretension and then to adopt some strengthening measures to mitigate future problems. Based on the geometrically nonlinear vibration of a rectangular orthotropic membrane structure, a nondestructive detection method for monitoring its pretension is developed in this article. This method is achieved by impacting a low-velocity pellet onto the membrane surface to generate vibration and detecting its response amplitude. Then the detected amplitude is converted into a pretension estimate via a derived formula. In addition, experiments for three kinds of conventional membrane material (Heytex H5573, Xing Yi Da, and ZZF 3010) were carried out according to the theoretical idea. The experimental results proved this method is feasible and verified the theoretical derivation is reasonable.

The inner boundary and the cristae membrane are connected by pore-like structures termed crista junctions (CJs). The MICOS complex is required for CJ formation and enriched at CJs. Here, we address the roles of the MICOS subunits Mic27 and Mic10. We observe a positive genetic interaction between Mic27 and Mic60 and deletion of Mic27 results in impaired formation of CJs and altered cristae membrane curvature. Mic27 acts in an antagonistic manner to Mic60 as it promotes oligomerization of the F1FO-ATP synthase and partially restores CJ formation in cells lacking Mic60. Mic10 impairs oligomerization of the F1FO-ATP synthase similar to Mic60. Applying complexome profiling, we observed that deletion of Mic27 destabilizes the MICOS complex but does not impair formation of a high molecular weight Mic10 subcomplex. Moreover, this Mic10 subcomplex comigrates with the dimeric F1FO-ATP synthase in a Mic27-independent manner. Further, we observed a chemical crosslink of Mic10 to Mic27 and of Mic10 to the F1FO-ATP synthase subunit e. We corroborate the physical interaction of the MICOS complex and the F1FO-ATP synthase. We propose a model in which part of the F1FO-ATP synthase is linked to the MICOS complex via Mic10 and Mic27 and by that is regulating CJ formation.

The existing large inflatable membrane structure is complex in structure and takes a long time to be extended. In this paper, an air-ribbed skeleton membrane structure is proposed to meet the requirement of camp and emergency tents needing to be set up quickly and easily. Ten single-arch air ribs are arranged side by side to support the tarpaulin, and wind ropes are added to the end and side faces of the tarpaulin to remain stable. The finite element model of the air-ribbed skeleton membrane structure is established to analyze the stress and the displacement of the membrane structure under combined wind and snow loads. The maximum displacement (439.4 mm) and maximum stress (29.94 MPa) are both within the safe standard. The stress and the displacement of the membrane structure in the wind load case is affected by the angle of the wind. The value of maximum stress and displacement at the wind angle of 90° are both lower than those at 0° and 45° in the wind load case. It is advisable to align the site layout of the membrane structure at the wind angle of 90°. The effect of the angle of wind ropes on the stress and displacement of the membrane structure is also studied. The maximum stress and displacement in the case when the angle of wind rope is 30° is smaller than those in the case when the angle of wind ropes is 45°. It is recommended that the wind rope should be laid at 30° to reinforce the membrane structure.

Fault diagnostics present a crucial technical issue in the areas of both the condition monitoring of machines and the monitoring of structural health. The identification of faults at an early stage in their development has an immense effect on the safety of monitored structures. Correct identification allows for the monitoring of the development of faults and the choosing of optimal operation strategies. This article discusses a method of monitoring structural health, based on the application of the Hilbert transforms (GHT and FrHT) for detecting fault formations and their development in membrane structures. A signal resulting from the HT is analyzed using spectral analysis to identify features indicating the technical state. [ABSTRACT FROM AUTHOR]