Search Results (204)

Background: No Fourier transform infrared (FTIR) spectroscopy studies have directly evaluated adrenalectomy vessels, the technique’s established ability to probe collagen/elastin-associated spectral features and lipid peroxidation-related signatures, and protein structural damage. Stable gastric pentadecapeptide BPC 157 therapy was found to maintain the vascular function under severe stress, as FTIR spectroscopy recently demonstrated rapid peptide-induced molecular changes in healthy rat blood vessels, particularly in lipid content and protein secondary structure. Methods: To extend these findings and highlight the BPC 157 vascular background in the special circumstances of the course following unilateral adrenalectomy, abdominal aortas were collected at 15 min, 5 h, and 24 h after unilateral adrenalectomy for the FTIR spectroscopy assessment. Results: FTIR spectra were acquired, preprocessed, and analyzed using principal component analysis (PCA), support vector machine discriminant analysis (SVMDA), and band-specific statistics. BPC 157 (10 ng/kg intragatrically immediately after unilateral adrenalectomy) produced a clear, reproducible separation of aortic spectra from control samples at all time points. The main discriminatory spectral signatures were observed in three regions, including amide I and amide II (protein-related bands, consistent with collagen/elastin contributions) and lipid C–H stretching bands. These spectral signatures are consistent with early extracellular matrix reinforcement and membrane preservation in the vascular wall and align with the recovering effect on the lesions in counteraction of the severe vascular and multiorgan failure, attenuation/elimination of thrombosis and blood pressure disturbances in various occlusion/occlusion-like syndromes. Conclusions: Together, after unilateral adrenalectomy, the FTIR data provide molecular-level spectral signatures consistent with rapid remodeling of the aortic wall toward a more structurally stable and functionally favorable state. Full article

Biaxially stretched polytetrafluoroethylene (PTFE) membranes are promising media for high-efficiency air filtration because of their stable node–fiber microstructure and environmental durability. To clarify how resin properties and microstructure govern filtration behavior, ten PTFE resins with different average molecular weights (Mn) and particle size characteristics were processed into membranes under essentially identical biaxial stretching and sintering conditions. Resin particle size, fiber diameter and pore size distributions were quantified, and coefficients of variation (CVs), together with Spearman rank correlations, were used to analyze material–structure–performance links. Filtration efficiency, pressure drop and quality factor (QF) were measured according to ISO 29463-3 using 0.1–0.3 μm aerosols. Higher Mn combined with lower particle-size dispersion favored finer fibers and narrower pores, yielding efficiencies close to 100%, but increased pressure drop and slightly reduced QF, indicating a trade-off between efficiency and flow resistance. The sample with the lowest Mn in its group and a high machine-direction draw ratio (12×), showed pronounced fibril breakage, node coalescence, broadened pore-size distribution and degraded QF, illustrating the sensitivity of structure and performance to resin-process mismatch. Overall, the study establishes a hierarchical material–fiber–pore–performance relationship that can guide resin selection, structural tuning and process optimization of biaxially stretched PTFE membranes. Full article

Diabetic cataract (DC) is a major complication of diabetes, with human lens epithelial cells (HLECs) playing a central role in its pathogenesis. Gigantol, a natural compound, has demonstrated protective effects against HLEC damage, yet its underlying mechanisms, particularly concerning cellular biophysical properties, remain poorly understood. This study investigated the protective role of gigantol against high-glucose-induced damage in HLECs, with a specific focus on alterations in cellular biophysical properties. Using a multi-technique approach including transmission electron microscopy (TEM), atomic force microscopy, laser scanning confocal microscopy, and Raman spectroscopy, we analyzed changes in ultrastructure, morphology, stiffness, roughness, membrane fluidity, and cytoskeletal organization. Treatment with gigantol effectively restored cellular ultrastructure, mitigated cytoskeletal disruption, and normalized key biomechanical properties: it reduced cell stiffness and roughness by approximately one-fourth, increased cell height by nearly onefold, and enhanced membrane fluidity by one-fifth. Raman spectroscopy indicated that gigantol improved membrane fluidity by modulating lipid bilayer structure, specifically through alterations in –CH₂– bending and –C=C– stretching modes. These findings demonstrate that gigantol protects HLECs from high-glucose-induced damage not only by biochemical means but also by restoring cellular biophysical homeostasis. This study provides novel biophysical–pathological insights into the anti-cataract mechanism of gigantol, highlighting its potential as a therapeutic agent that targets both biochemical and biophysical aspects of DC. Full article

Contaminated water detoxification remains difficult due to the presence of persistent halo-organic contaminants, such as perfluorooctanoic acid (PFOA) and chlorophenols, which are chemically stable and resist conventional purification methods. Functionalized membrane-based separation and decontamination have garnered immense attention in recent years. Commercially available microfiltration membrane (PVDF) and polymeric non-woven fiber filters (glass and composite) are functionalized with poly(methacrylic acid) (PMAA) that shows outstanding pH-responsive performance and tunable water permeability under ambient conditions perfect for environmental applications. Polymer loading based on weight gain measurements on PMAA–microglass composite fibers (137%) and microglass fibers (116%) confirmed their extent of functionalization, which was significantly greater than that of PVDF (25%) due to its widely effective pore diameter. Presence of chemically active hydrogel within PVDF matrix was validated by FTIR (hydroxyl/carbonyl) stretch peak, substantial decrease in contact angle (68.8° ± 0.5° to 30.8° ± 1.9°), and decrease in pure water flux from 509 to 148 LMH/bar. Nanoparticles are generated both in solution and within PVDF using simple redox reactions. This strategy is extended to PVDF-PMAA membranes, which are loaded with Fe/Pd nanoparticles for catalytic conversion of 4-chlorophenol and PFOA, forming Fe/Pd-PVDF-PMAA systems. A total of 0.25 mg/L Fe/Pd nanoparticles synthesized in solution displayed alloy-type structures and demonstrated a strong catalytic performance, achieving complete hydrogenation of 4-chlorophenol to phenol and 67% hydrogenation of PFOA to its reduced form at 22–23 °C with ultrapure hydrogen gas supply at pH 5.7. These results underscore the potential of hybrid polymer–nanoparticle systems as a novel remediation strategy, integrating tunable separation with catalytic degradation to overcome the limitations of conventional water treatment methods. Full article

Blow spinning is a low-cost and versatile method that permits the large-scale production of fibrous membranes. However, polysaccharides that show numerous merits such as biocompatibility and biodegradability often have a low spinnability due to their high chain rigidity and low ability to form sufficient entanglements. Here, we report the fabrication of polysaccharide micro-fibrous membranes from sodium alginate/polyethylene oxide solutions formulated in solvent mixtures of water and ethanol. The shear and extensional rheological responses of the solutions are characterized, and parameters including specific shear viscosity, reptation time, extensional relaxation time, and maximum stretch ratio are correlated with the concentrations of polymer, polyethylene oxide, and ethanol. It is found that flexible polyethylene oxide and poorer solvent ethanol can synergistically delay the chain relaxation during stretch and increase the stretchability of the solutions. A processability map of the solutions for blow spinning is constructed, enabling the fabrication of fibrous membranes with a fiber diameter of ~1 μm, tensile strength of 4.89 MPa, elongation at break of 15.24%, and Young’s modulus of 45.43 MPa. This study presents a new strategy to fabricate sodium alginate-based membranes, which should provide insights into the design of other polysaccharide membranes with specific functions and applications. Full article

In recent years, the development of stretchable electronic devices with mechanical properties similar to those of human tissues has attracted increasing research interest in biomedical engineering, wearables, and other fields. These devices have demonstrated, and some other researchers have already shown, promising advancements towards applications that span from measurements of the disruption of model barrier tissues to wearable or implantable devices, soft robotics, and the development of flexible and stretchable batteries. For example, models of barrier tissues, consisting of two compartments separated by a porous membrane, have been used to measure their integrity as well as to investigate the passage of drugs, toxins, and cancer cells through these tissues. Some of these models include an elastomeric membrane which can be stretched to model processes such as breathing and gut peristalsis, while others include electrodes for real-time measurement of barrier tissue integrity. However, to date, microelectrodes have not been fabricated directly on a porous elastomeric membrane. Here, we present lithographically patterned gold electrodes on porous PDMS membranes that enable electronic sensing capabilities in addition to mechanical manipulation. These membranes are incorporated into vacuum-actuated devices which impart cyclic mechanical strain, and their suitability for electrical impedance measurements, even after 1000 stretching cycles under fluids similar to cell culture media, is demonstrated. In the future, we expect to use these electrodes to measure the disruption in model cell barriers as well as to dielectrophoretically trap cells in a region of interest for more rapid assembly of a model tissue. Other areas like wearables, robotics, and power sources will greatly benefit from the further development of this technology. Full article

Biobutanol can be obtained by fermentation of microorganisms and used as biofuel. The membrane separation is energetically favorable. The incorporation of butanol into syndiotactic polystyrene (sPS) with crystalline nanopores was investigated as a function of the butanol uptake temperature using infrared spectroscopy. The OH stretching modes at 3596 and 3300 cm⁻¹, corresponding to hydrogen-bonded butanol in the crystalline cavity and free butanol in the amorphous region, respectively, were employed for analysis. Upon immersion of the sPS film in butanol, butanol molecules were absorbed in the crystalline nanocavities and amorphous phase. Diffusion increased with the uptake temperature in both regions. This can be associated with the larger molecular mobility of butanol molecules at high temperatures, facilitating contact between the film surface and the butanol molecules. The number of butanol molecules incorporated into the crystalline cavity was estimated using Lambert-Beer’s law. On average 90% of the nanopore cavities were occupied by butanol, while the remaining 10% were empty. Full article

The inner mitochondrial membrane proteins ATP/ADP carrier protein 1 (AAC1) and Uncoupling protein 1 (UCP1) belong to the SLC25 mitochondrial carrier family. AAC1 is responsible for ATP/ADP exchange, while UCP1-dependent proton transport, which also requires small molecules known as activators, is the basis of brown fat thermogenesis. Arachidonic acid (AA) is an endogenous activator capable of inducing proton transport in both proteins. As such, both AAC1- and UCP1-dependent proton transport are potential targets of weight loss drugs. While AAC1 structures have long been available, only recently have structures of UCP1 been determined. Unfortunately, no AA-bound structure of either protein is available. To explore their interactions with AA, we performed molecular dynamics (MD) simulations of both proteins. Six parallel simulations of each protein were run with an average length of just over 6 μs, for a total of 75 μs of aggregate simulation across both proteins. AA bound deeply between transmembrane helix (TM) helices or in the central cavity of AAC1 in 14 events and between TM helices of UCP1 in 6 events. All AA involved in these deep binding events came from the intermembrane space-facing (C) leaflet. In AAC1, AA most often bound between TM1/TM2 and TM5/TM6. In four cases the fatty acid bound at the bottom of the central cavity rather than in an interhelical groove. In UCP1, all but one deeply bound AA sat between TM5 and TM6. No AA fully entered the cavity as observed in AAC1. In addition to entering the proteins, AAs were enriched around them in the surrounding membrane adjacent to the TM helices. While both protein structures exhibit hydrophobic stretches separating the intermembrane space (IMS) from the matrix, water wires formed through both AAC1 and UCP1, connecting the bulk water in both regions. Grotthuss shuttling along water wires has been proposed as a possible mechanism of AAC1/UCP1-dependent proton transport, but water wires are not present in experimental structures and have not previously been reported in MD simulations. Calculations of electric potentials along these water wires find a large 0.75–1 V electrostatic barrier along water wires through AAC1 and a substantially smaller such barrier of ~0.5 V through UCP1. Full article

Changes in membrane lipid composition constitute a key bacterial resistance mechanism. In Staphylococcus aureus, phosphatidylglycerol undergoes lysine modification to form lysyl-phosphatidylglycerol, a cationic lipid that reduces the net negative surface charge and thereby enhances resistance to cationic antimicrobial peptides. In this study, we examined the influence of lysyl-PG on the membrane activity of three antimicrobial peptides with distinct physicochemical characteristics: LL-37, F5W Magainin II, and NA-CATH:ATRA-1-ATRA-1. Model membranes composed of phosphatidylglycerol and cardiolipin were supplemented with increasing molar fractions of lysyl-phosphatidylglycerol, and peptide–membrane interactions were characterized using Fourier-transform infrared spectroscopy. Membrane fluidity was evaluated through shifts in the symmetric methylene stretching bands, while changes in interfacial polarity were assessed via the carbonyl and phosphate asymmetric stretching bands. LL-37 induced pronounced disruption of anionic bilayers, an effect progressively attenuated by lysyl-phosphatidylglycerol, particularly within the hydrophobic core. F5W Magainin perturbed both hydrophobic and interfacial regions across a broader range of lysyl-phosphatidylglycerol concentrations, whereas NA-CATH:ATRA-1-ATRA-1 primarily targeted interfacial domains, with minimal disruption of acyl chain order. Increasing lysyl-PG content modulated the extent of bilayer disorder and dehydration at the hydrophobic–hydrophilic interface, with each peptide exhibiting a distinct interaction profile. Collectively, these findings provide mechanistic insights into lysyl-PG-mediated modulation of peptide activity and highlight the role of lipid remodeling as a bacterial defense strategy. Full article

Although hypergravity may influence cardiac mechanosensitivity, the effects on specific ion channels remain inadequately understood. This research examined the effects of long-term hypergravity on the functional activity and transcriptional expression of mechanosensitive channels (MSCs) in rat ventricular cardiomyocytes. After 14 days of exposure to 4g, rats were subjected to molecular and electrophysiological analyses. Significant remodeling of MSC-encoding genes was revealed by RNA-seq. Trpm7 (+41.23%, p = 0.0073) and Trpc1 (+68.23%, p = 0.0026) were significantly upregulated among non-selective cation channels, while Trpv2 (−62.19%, p = 0.0044) and Piezo2 (−57.58%, p = 0.0079) were significantly downregulated. Kcnmb1 (−47.84%, p = 0.0203) was suppressed, whereas Traak/K2P4.1 showed a strong increase (+239.48%, p = 0.0092), among K⁺-selective MSCs. Furthermore, Kir6.1 was significantly downregulated (−75.8%, p = 0.0085), whereas Kir6.2 was significantly upregulated (+38.58%, p = 0.0317). These results suggest targeted transcriptional reprogramming that suppresses pathways associated with maladaptive Ca²⁺ influx while enhancing Ca²⁺-permeable mechanosensitive channels alongside stabilized K⁺ conductance. At the structural level, cardiomyocytes from hypergravity exposure showed a 44% increase in membrane capacitance, consistent with hypertrophic remodeling, and sarcomere elongation (p < 0.001). Functionally, stretch-activated current (I_SAC) was markedly hypersensitive in patch-clamp analysis: currents were induced at very small displacements (1–2 µm) and were significantly larger under 4–10 µm stretch (222–107% of control values). These findings indicate that chronic hypergravity induces coordinated molecular, structural, and functional remodeling of cardiomyocytes, characterized by increased membrane excitability, compensatory stabilizing mechanisms, and enhanced Ca²⁺ signaling. This demonstrates the flexibility of cardiac mechanotransduction under prolonged gravitational stress, with potential implications for understanding cardiovascular risks, arrhythmias, and hypertrophy associated with altered gravity environments. Full article

To expand the application of silver nanowires (AgNWs) in the field of flexible sensors, this study developed a stretchable flexible sensor based on thermoplastic polyurethane (TPU). Initially, the TPU nanofiber membrane was prepared by electrospinning. Subsequently, high-aspect-ratio AgNWs were synthesized via a one-step polyol reduction method. The AgNWs with the optimal aspect ratio were selected for the conductive layer and spray-coated onto the surface of the TPU nanofiber membrane. Another layer of TPU nanofiber membrane was then laminated on top, resulting in a flexible thin-film sensor with a “sandwich” structure. Through morphological, chemical structure, and crystallinity analyses, the primary factors influencing AgNWs’ growth were investigated. Performance tests revealed that the prepared AgNWs had an average length of approximately 130 μm, a diameter of about 80 nm, and an average aspect ratio exceeding 1500, with the highest being 1921. The obtained sensor exhibited a low initial resistance (26.7 Ω), high strain range (sensing, ε = 0–150%), high sensitivity (GF, over 19.21), fast response and recovery time (112 ms), and excellent conductivity (428 S/cm). Additionally, the sensor maintained stable resistance after 3000 stretching cycles at a strain range of 0–10%. The sensor could output stable and recognizable electrical signals, demonstrating significant potential for applications in motion monitoring, human–computer interaction, and healthcare fields. Full article

Rice membrane-covered cultivation offers notable agronomic advantages, including effective weed suppression and improved moisture retention. However, current mechanized approaches remain constrained by high labor requirements, low operational efficiency, and the inherent fragility of biodegradable membranes. To address these limitations, this study integrates a high-speed synchronous membrane-covering device, governed by a PSO-Fuzzy PID control algorithm, into a conventional rice transplanter. This integration enables precise coordination between membrane-laying and transplanting operations. The mechanical properties of the membranes were analyzed, and a tension evaluation model was developed considering structural parameters and roll diameter variation. Experimental tests on three biodegradable membranes revealed an average thickness of 0.012 mm, a longitudinal tensile force of 0.57 N, and a tensile strength of 2.85 N/mm. The PSO algorithm was employed to optimize fuzzy PID parameters (K = 5.3095, K_p = 10.6981, K_i = 0.0100, K_d = 8.2892), achieving adaptive synchronization between membrane output speed and transplanter travel speed. Simulation results demonstrated that the PSO-Fuzzy PID reduced rise time by 53.13%, stabilization time by 90.58%, and overshoot by 3.3% compared with the conventional PID. In addition, a dedicated test bench for the membrane-covering device was designed and fabricated. Orthogonal experiments determined the optimal parameters for the speed-measurement system: a membrane pressure of 5.000 N, a roller width of 28.506 mm, and a placement angle of 0.690°. Under these conditions, the minimum membrane-stretching tension was 0.55 N, and the rotational speed error was 0.359%. Field tests indicated a synchronization error below 1.00%, a membrane-width variation rate below 1.50%, and strong anti-interference capability. The proposed device provides an effective solution for intelligent and fully mechanized rice transplanting. Full article

The rise of multidrug-resistant pathogens has become a serious health concern, creating an urgent need for novel therapeutic approaches. Among the compounds explored, AMPs have emerged as promising candidates due to their broad-spectrum activity and low propensity for resistance development. However, their clinical implementation is limited by improper size, in vivo instability, and toxicity. Here, we designed short analogs of CeHS-1 via (1) truncation of intact CeHS-1, (2) amino acid substitution, (3) end-tagging, and (4) C-terminal amidation. The results showed that short analogs fused with an RWW stretch exhibited stronger antibacterial activity than the parent analogs, without inducing hemolysis in human red blood cells. Among the tested AMPs, mechanistic studies revealed membrane-disruptive activity of certain peptides against Staphylococcus aureus. In silico analyses also suggested that the analogs bind DNA by aligning parallel to its grooves, where the RWW stretch is believed to contribute to interactions between arginine and tryptophan residues and nitrogenous bases through electrostatic, hydrogen bonding, and hydrophobic interactions. The short CeHS-1 analogs established here may serve as potential alternative antimicrobial agents, which should be tested in clinical trials in the future. Full article

Superhydrophobic and superoleophilic nanofibrous or microfibrous membranes are regarded as ideal oil/water separation materials owing to their controllable porosity, superior separation efficiency, and ease of operation. However, developing efficient, scalable, and environmentally friendly strategies for fabricating such membranes remains a significant challenge. In this study, isotactic polypropylene (iPP) fibrous membranes with morphologies ranging from ellipsoidal stacking to microfiber stacking were successfully fabricated via a multistage stretching extrusion and leaching process using in situ microfibrillar composites (MFCs). The results establish a significant relationship between microfiber morphology and membrane oil adsorption performance. Compared with membranes formed from high-aspect-ratio microfibers, those comprising short microfibers feature larger pores and a more open structure, which enhances their oil adsorption capacity. Among the fabricated membranes, the iPP membrane with an ellipsoidal stacking morphology exhibits optimal performance, achieving a porosity of 65% and demonstrating both hydrophobicity and superoleophilicity, with a silicone oil adsorption capacity of up to 312.5%. Furthermore, this membrane shows excellent reusability and stability over ten adsorption–desorption cycles using chloroform. This study presents a novel approach leveraging in situ microfibrillar composites to prepare high-performance oil/water separation membranes in this study, underscoring their considerable promise for practical use. Full article

Cardiomyocytes, similarly to cells in various tissues, are responsive to mechanical stress of all types, which is reflected in the significant alterations to their electrophysiological characteristics. This phenomenon, known as mechanoelectric feedback, is based on the work of mechanically gated channels (MGCs) and mechano-sensitive channels (MSCs). Since microgravity (MG) in space, as well as simulated microgravity (SMG), changes the morphological and physiological properties of the heart, it was assumed that this result would be associated with a change in the expression of genes encoding MGCs and MSCs, leading to a change in the synthesis of channel proteins and, ultimately, a change in channel currents during cell stretching. In isolated ventricular cardiomyocytes of rats exposed to SMG for 14 days, the amount of MGCs and MSCs gene transcripts was studied using the RNA sequencing method by normalizing the amount of “raw” reads using the Transcripts Per Kilobase Million (TPM) method. Changes in the level of channel protein, using the example of the MGCs TRPM7, were assessed by the Western blot method, and changes in membrane ion currents in the control and during cardiomyocyte stretching were assessed by the patch-clamp method in the whole-cell configuration. The data obtained demonstrate that SMG results in a multidirectional change in the expression of genes encoding various MGCs and MSCs. At the same time, a decrease in the TPM of the MGCs TRPM7 gene leads to a decrease in the amount of TRPM7 protein. The resulting redistribution in the synthesis of most channel proteins leads to a marked decrease in the sensitivity of the current through MGCs to cell stretching and, ultimately, to a change in the functioning of the heart. Full article