Search Results (410)

Background/Objectives: To review the dimensions of the round window region (round window niche, bony structures surrounding the niche, and the membrane itself). Methods: Medline, EMBASE, Cochrane Library, and Google Scholar databases were searched by two independent reviewers. Anatomical and radiological studies on the round window region were screened. Studies reporting at least one dimension for the round window (RW) niche and/or the RW membrane were included. Results: Sixteen studies met the inclusion criteria (13 anatomical and 3 radiological studies) for a total number of 808 temporal bones with at least one dimension reported. The structures measured varied across the different studies with 12 reporting RW membrane dimensions (area and/or at least one distance), 8 detailing RW niche dimensions (height, width or depth) and 6 which measured at least one element of the RW bony overhangs (posterior or anterior pillar, RW tegmen). Surface area of the RW membrane varied between 0.32 mm² and 2.89 mm², with a minimum dimension (minimum diameter or height or width) comprising between 0.51 mm and 2.1 mm. When the bony overhangs surrounding the membrane were not considered, the minimum diameter was between 1.65 mm and 1.97 mm. Conclusions: The dimensions of the RW region are intrinsically variable, but the heterogeneity of the measurements reported also contributes to these variations. Posterior pillar, RW tegmen, anterior pillar, and their relative development probably account for a large part of this variability. The future RW membrane devices should be ≤1 mm in their maximum dimension, whether or not individually tailored, to fit most of the RW membranes. Full article

One of the key challenges in commercializing proton exchange membrane (PEM) electrolyzer technology is reducing the production costs while maintaining high efficiency and operational stability. Significant contributors to the overall cost of the device are the electrode catalysts with IrO₂ and Pt/C. Due to the high cost and limited availability of noble metals, there is growing interest in developing alternative, low-cost catalytic materials. In recent years, two-dimensional transition metal dichalcogenides (2D TMDCs), such as molybdenum disulfide (MoS₂) and rhenium disulfide (ReS₂), have attracted considerable attention due to their promising electrochemical properties for hydrogen evolution reactions (HERs). These materials exhibit unique properties, such as a high surface area or catalytic activity localized at the edges of the layered structure, which can be further enhanced through defect engineering or phase modulation. To increase the catalytically active surface area, the investigated materials were deposited on a carbon-based support—Vulcan XC-72R—selected for its high electrical conductivity and large specific surface area. This study investigated the physicochemical and electrochemical properties of six catalyst samples with varying MoS₂ and ReS₂ to carbon support ratios. Among the composites analyzed, the best sample on MoS₂ (containing the most carbon soot) and the best sample on ReS₂ (containing the least carbon soot) were selected. These were then used as cathode catalysts in an experimental PEM electrolyzer setup. The results confirmed satisfactory catalytic activity of the tested materials, indicating their potential as alternatives to conventional noble metal-based catalysts and providing a foundation for further research in this area. Full article

Nafion, while a benchmark proton exchange membrane (PEM) for fuel cells, suffers from significant performance degradation at elevated temperatures and low humidity due to dehydration and diminished mechanical stability. To address these limitations, this study investigated the development and characterization of Nafion nanocomposite membranes incorporating sulfonated silica layered materials (sSLMs). The inherent lamellar structure, high surface area, and abundant sulfonic acid functionalities of sSLMs were leveraged to synergistically enhance membrane properties. Our results demonstrate that sSLM incorporation significantly improved ion exchange capacity, water uptake, and dimensional stability, leading to superior water retention and self-diffusion at higher temperatures. Critically, the nanocomposite membranes exhibited remarkably enhanced proton conductivity, particularly under demanding conditions of 120 C and low relative humidity (i.e., 20% RH), where filler-free Nafion largely ceases to conduct. Single H₂/O₂ fuel cell tests confirmed these enhancements, with the optimal sSLM-Nafion nanocomposite membrane (N-sSLM₅) achieving a two-fold power density improvement over pristine Nafion at 120 C and 20% RH (340 mW cm⁻² vs. 117 mW cm⁻² for Nafion). These findings underscore the immense potential of sSLM as a functional filler for fabricating robust and high-performance PEMs, paving the way for the next generation of fuel cells capable of operating efficiently under more challenging environmental conditions. Full article

Background: The active (remote) loading of drugs into nanoparticulate systems via the pH gradient technique has been proven highly successful in liposomes, as numerous formulations have reached the market. However, this is not the case for niosomes, as the full potential of this area remains largely undiscovered. The purpose of this research is to study the effect of different co-surfactants (Cremophor RH 40, Cremophor ELP and Solutol HS-15) on stabilising the niosomal membrane to enable the creation of a pH gradient. Methods: For visualisation of pH gradients, pH indicator bromocresol green (BCG) was used as a novel encapsulated model molecule to visually investigate the ability of niosomes to entrap drugs through active loading. Thereafter, the optimised BCG niosomal formulation was applied to encapsulate a therapeutic drug molecule, doxorubicin, via pH gradient active loading. Niosomes were formulated via thin-film hydration using Span 60, cholesterol, with or without co-surfactants. Thin films were hydrated with either Trizma buffer or HEPES buffer for BCG, or ammonium sulfate for doxorubicin. The niosomes’ outer membrane pH was adjusted via either the addition of HCl or citric acid in the case of BCG, or by passing the niosomes through a Sephadex G50 gel column, pre-equilibrated with PBS or Trizma buffer, in the case of doxorubicin. Results: Niosomes formulated with Span 60 and cholesterol could not be formed at acidic pH and thus could not create a pH gradient. All three co-surfactants, when added to Span 60 and cholesterol, stabilised the niosomes and enabled them to form a pH gradient. Niosomes (after size reduction) containing Solutol HS-15 showed significantly higher entrapment efficiency of BCG when compared to Cremophor RH 40 and Cremophor ELP (67.86% vs. 15.57% vs. 17.81%, respectively, with sizes of 159.6 nm, 177.9 nm and 219.1 nm, respectively). The use of HEPES buffer resulted in a higher EE of BCG compared to Trizma buffer (72.85% vs. 67.86%) and achieved a size of 283.4 nm. The Solutol HS-15 containing formulation has exhibited 68.28% EE of doxorubicin with ammonium sulfate as the inner buffer, while the external buffer was Trizma with a size of 241.1 nm after extrusion. Conclusions: Niosomal formulations containing Solutol HS-15 are highly promising for remote drug loading. The novel use of BCG for studying pH gradient and drug loading into niosomes has proved beneficial and successful. Full article

The primary challenge associated with stainless steel in fuel cell operation is its susceptibility to corrosion, which leads to increased contact resistance and subsequent degradation of electrochemical performance. In general, the protective layers have been loaded onto the metal surface by widely used traditional techniques such as physical vapor deposition (PVD), or cathode arc ion plating. However, the above sputtering and evaporation ways require a high-vacuum condition, complicated experimental setups, higher costs, and an elevated temperature. Therefore, herein the achievement for uniform coatings over a large surface area has been realized by using a cost-effective strategy through a complete wet chemical process. The synergistic regulation of two conductive components and a plastic additive has been employed together with the entrapment of a surfactant to optimize the microstructure of the coating surface. The assembly of layered graphite and a polystyrene sphere could maintain both the high corrosion resistance feature and excellent electrical conductivity. In particular, the intrinsic vacant space in the above physical barriers has been filled with fine powders of indium tin oxide (ITO) due to its small size, and the interconnected conductive network with vertical/horizontal directions would be formed. All the key technical targets based on the U.S. Department of Energy (DOE) have been achieved under the simulated operating environments of a proton exchange membrane fuel cell. The corrosion current density has been measured as low as 0.52 μA/cm² (for the sample of graphite/mixed layer) over the applied potentials from −0.6 V to 1.2 V and its protective efficiency is evaluated to be 99.8%. The interfacial contact resistance between the sample and the carbon paper is much less than 10 mΩ·cm² (3.4 mΩ·cm²) under a contact pressure of 165 N/cm². The wettability has been investigated and its contact angle has been evolved from 48° (uncoated sample) to even 110°, providing superior hydrophobicity to prevent water penetration. Such an innovative approach opens up new possibilities for improving the durability and reducing the costs of carbon-based coatings. Full article

Flexoelectricity arises in materials under strain gradients, which can be particularly significant for situations in which the existence of other electromechanical properties is absent or generating large flexoelectric properties is achievable. This effect has also been observed in some biological materials, whose understanding can hugely help to further enhance our understanding of vital biological processes like mechanotransduction, as well as the development of applications in regenerative medicine and drug delivery. While the field of flexoelectricity as a relevant topic in biological materials is relatively new and still developing, the current study aims to review available results on flexoelectric effects in biological materials such as cells and cell membranes, hearing mechanisms, and bone, and their potential applications in biomedical research. Therefore, we first provide a brief background on two main electromechanical couplings (piezoelectricity and flexoelectricity) and further, how flexoelectricity has been experimentally and theoretically identified. We then review flexoelectricity in different biological materials as the main aim of the current study. Within that, we provide additional emphasis on the influence of this effect on bone and bone remodeling. In particular, the study outlines current limitations and provides potential directions for future work, emphasizing the crucial role in the development of next-generation electromechanical devices and optimizing their function in the area of biomedical research. Full article

Air-supported membrane structures (ASMS) are widely applied in warehouses and large-span venues due to their lightweight and cost-effective nature. However, as a storage building with a lot of combustible material and significant fire hazards, it imposes stringent demands on structural stability and safety. This paper investigates the impact of fire-induced effects on stability using Fire Dynamics Simulator (FDS) software, with a case study focusing on an ASMS coal storage bin. The study comprises two key components: (1) internal pressure stability and (2) thermal stability. Results show that ambient temperature, leakage area and air supply govern non-fire pressure stability, with a 10 K increase reducing pressure by 9.4 Pa. During fires, HRR, location and growth type effect the stability of ASMS buildings. Thermal stability analysis reveals 6 m horizontal spacing can prevent coal ignition (<12.5 kW/m², <100 °C), while 10 m vertical spacing can avoid PVC membrane pyrolysis. These findings provide critical design guidelines for ASMS fire protection, highlighting the necessity of asymmetric safety margins due to vertical–horizontal radiation anisotropy. Full article

We study a computational model of a protocell, in which an autocatalytic reaction sustains itself inside a lipid vesicle. The autocatalytic reaction drives volume growth via osmosis. Membrane area grows due to addition of lipids from the environment. The membrane growth rate depends on the external lipid concentration and on the tension in the membrane. In the absence of division, a cell either reaches a state of homeostasis or grows to a point where the internal reaction collapses. If a cell becomes elongated, it can divide into two smaller spherical vesicles, conserving the total volume and area. We determine when it is energetically favorable for a large vesicle to divide. Division requires the buildup of a difference between the lipid areas on the outer and inner leaflets of the membrane. Division occurs most easily when the rate of flipping of lipids between leaflets is relatively slow. If the flipping is too fast, the parent cell grows large without dividing. There is a typical size at which division occurs, producing two daughter cells of unequal sizes. The smaller and larger daughters regrow to the same typical size before the next division. Protocells with an active metabolism reach a stable state where the internal autocatalytic reaction and the membrane growth are well balanced. Active protocells can grow and divide in conditions where an inactive vesicle without an internal reaction cannot. Full article

Background: The use of antimicrobial peptides (AMPs) as biotechnological tools is an area of growing interest in the research that seeks to improve crop defense. SmAP_α1–21 and SmAP_γ27–44 were previously reported to inhibit Fusarium graminearum, permeabilize the plasma membrane and induce cytoplasmic disorganization. To exert its activity, SmAP_α1–21 initially enters through the basal and apical cells of F. graminearum conidia and then displays a general but non-homogeneous distribution in the cytoplasm of all conidial cells, in contrast. Methods: We analyzed, focusing on membrane interaction, the mode of action of SmAP_γ27–44, a peptide based on the γ-core of defensins DefSm2-D and DefSm3, and SmAP_α1–21, based on the α-core of DefSm2-D. Additionally, we compared the behavior of SmAP_α1–21 with that of SmAP3_α1–21 based on DefSm3 but with no activity against F. graminearum. Results: In this study, we showed that SmAP_γ27–44 enters the cells with discrete intracellular localization. Furthermore, both peptides disrupted the plasma membrane, but with different modes of action. When large unilamellar liposomes (LUVs) containing phosphatidic acid and ergosterol were used as a filamentous fungal plasma membrane model, SmAP_γ27–44 strongly induced aggregation concomitantly with the solubilization of the liposomes and showed the maximal insertion of its tryptophan moiety into the membrane’s hydrophobic interior. In comparison, SmAP_α1–21 showed a high effect on the ζ potential of anionic vesicles, vesicle aggregation capacity after reaching a concentration threshold, and moderate transfer of tryptophan to the membrane. SmAP3_α1–21, on the other hand, showed poor superficial adsorption to liposomes. Conclusions: In view of our results, a cell penetration peptide-like effect was pictured for the γ-core defensin-derived peptide and a classical AMP action was observed for the α-core defensin-derived one. Full article

The development of sensitive and selective methods for detecting pesticide residues has become paramount for ensuring food safety. In this work, a high-performance molecularly imprinted electrochemical sensor based on the composite of Cu-BTC- and FeCo-ZIF-derived N-doped carbon (FeCo@NC), synthesized by pyrolysis and electrodeposition, was developed for Benomyl (BN) detection. The materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In this sensing system, the Cu-BTC/FeCo@NC composite used as the electrode substrate displayed a large specific surface area, high electronic conductivity, and rich active catalytic sites, demonstrating excellent electrocatalytic ability toward BN oxidation. Meanwhile, Cu-BTC, with its abundant surface functional groups, facilitated strong hydrogen bonding interactions with the imprinted template molecule of 3,4-ethylenedioxythiophene (EDOT), promoting the formation of a uniform molecularly imprinted membrane on the substrate material surface. The introduced MIP-PEDOT could enhance the selective recognition and enrichment of the target BN, leading to an amplified detection signal. Thanks to the synergistic effects between Cu-BTC/FeCo@NC and MIP-PEDOT, the proposed sensor achieved a low detection limit of 1.67 nM. Furthermore, the fabricated sensor exhibited high selectivity, reproducibility, and interference resistance in detecting BN. The method has been successfully applied to the determination of BN in vegetable and fruit samples, indicating its potential for use in practical applications. Full article

(1) Background: Musculoskeletal trauma from combat wounds, accidents, or surgeries is highly associated with infections and hospitalization. The current “gold standard” for such injuries when access to hospitals is limited is administering antibiotics and opioids; however, they are not ideal treatments due to their contributions to antibiotic resistance and the opioid epidemic. Electrospun chitosan acylated with lipids and loaded with hydrophobic drugs has been shown to release the therapeutics systemically and to prevent infections. (2) Methods: Electrospun chitosan membranes (ESCMs) were fabricated and acylated using decanoyl chloride. FTIR was used to confirm acylation through the presence of ester bonds and acyl chains. ESCMs were loaded with the quorum-sensing molecule cis-2-decenoic acid (C2DA) and the local anesthetic bupivacaine and then implanted in rat femurs for 3 days. Afterward, the rats were euthanized, and CFUs were measured on retrieved bone, tissue, and treatment material. (3) Conclusions: While ESCMs prevented bacterial growth on the surface of the material, controls outperformed treatment groups. This is possibly due to bupivacaine’s role in inhibiting sodium channels, which favors the production of Th2-type cytokines associated with immune response suppression. Furthermore, ESCMs provide a large surface area for bacteria to grow on and form bridges between nanofibers. Full article

α-Synuclein (αS) interacts with lipid membranes in neurons to form amyloid fibrils that contribute to Parkinson’s disease, and its non-amyloid-β component domain is critical in the fibrillation. In this study, the salt (NaCl) effect on the membrane interaction and fibril formation of αS_57–102 peptide (containing the non-amyloid-β component domain) was characterized at the molecular level because the αS_57–102 fibrils exhibited structural polymorphism with two morphologies (thin and thick) in the presence of NaCl but showed one morphology (thin) in the absence of NaCl. The membrane-bound conformation (before fibrillation) of αS_57–102 had two helical regions (first and second) on the membrane regardless of salt, but the length of the first region largely shortened when NaCl was present, exposing its hydrophobic area to the solvent. The exposed region induced two distinct pathways of fibril nucleation, depending on the molar ratios of free and membrane-bound αS_57–102: one from the association of free αS_57–102 with membrane-bound αS_57–102 and the other from the assembly among membrane-bound αS_57–102. The differences mainly affected the β-strand orientation and helical content within the fibril conformations, probably contributing to the thickness degree, leading to structural polymorphism. Full article

The presence of dissolved sulfides in feed seawater causes severe elemental sulfur fouling in the reverse osmosis (RO) process. However, current pretreatment methods suffer from large footprint, high energy consumption, and limitations in effluent quality. In this study, adsorption and microfiltration are merged into a single process for the pretreatment of sulfide-containing seawater. Powdered activated carbon (PAC) was selected for its superior adsorption capacity (14.6-fold) and faster kinetics (3.9-fold) for sulfide removal compared to granular activated carbon. The high surface area and multiple pore structures of PAC facilitate surface and intraparticle diffusion, as well as anion–π conjugation likely occur between PAC and sulfide. Polypropylene microporous membranes, capable of tolerating high PAC dosages, were used in the hybrid process. Long-term pilot tests demonstrated that the effluent (turbidity < 1 NTU and SDI₁₅ ≈ 2.50) met the quality requirements for RO unit feedwater, achieving 100% sulfide removal efficiency over 101 h, with no risk of PAC leakage throughout the entire operation process. The formation of a loose, porous PAC cake layer alleviates membrane fouling and enhances the retention and adsorption of metal(loid)s and sulfide. Moreover, the low permeate flux of the polymeric membranes significantly mitigates filter cake formation. The hybrid system adapts to variations in feedwater quality, making it highly suitable for desalination plants with limited space and budget. These findings offer valuable insights and practical guidance for advancing seawater desalination pretreatment. Full article

In the last decades, numerous dendrimers with a variety of potential biomedical applications have been developed and investigated. The aim of the present study was to evaluate the molecular mechanisms of interaction between two dendrimers with proven antibacterial activity (4-N,N-dimethylamino-1,8-naphthalimide (Dab) and 3-bromo-Dab (Dab-Br)) and POPC (1-palmitoyl-2-oleoylphosphatidylcholine) model membranes (monolayers and liposomes). The pressure-area isotherms and the compressional modulus of the monolayers revealed that Dab is likely to penetrate the hydrophobic region of POPC, whereas Dab-Br inserts mainly into the lipid headgroup area. This assumption was confirmed by FTIR-ATR of POPC liposomes containing Dab and Dab-Br dendrimers. In addition, Dab induced a higher lipid order in POPC large unilamellar vesicles (LUVs) compared to Dab-Br. Moreover, both dendrimers changed the negative zeta potential of POPC vesicles to positive values, with slightly higher effect of Dab-Br, indicating electrostatic interactions between the lipid headgroups and dendrimers. Furthermore, Dab was able to reduce the average POPC LUVs’ size, unlike Dab-Br. The visualization of giant unilamellar vesicles revealed that the increasing dendrimer concentration induced model membrane shrinking and complete disintegration, which was more prominent for Dab. Based on the experimental results, new fundamental knowledge about the destabilizing effect of dendrimers on model lipid membranes will be acquired with a focus on their application in pharmacology and clinical practice. Full article

Background: Biologics is an exciting and growing area of medicine. Within the larger field of biologics, the use of viral vectors and virus-like particles (VLPs) is increasingly common, making it crucial to develop innovative and practical unit operations for the related purification process. Objective: Some scientists and engineers propose that membrane-based downstream virus purification (MVP) platforms would allow for more scalable and cost-effective production of these critical particles. However, the so-cial, political, and ethical implications of these advancements remain largely unex-plored. This paper aims to explore various pivotal facets of MVP technology govern-ance and regulations within the U.S. context, including (1) government policy ar-rangements related to the implementation of the technologies, (2) stakeholder atti-tudes, policy preferences, and behaviors, and (3) the fundamental factors that shape these attitudes, policy preferences, and behaviors. Methods: In doing so, we analyze publicly available federal and state government documents pertaining to biomanu-facturing, healthcare, and legislative attempts. Additionally, we will perform a stake-holder analysis on relevant industries, healthcare service providers, and recipients. Conclusions: Our goal is to outline the socio-political, ethical, and regulatory factors pertaining to the regulation and governance of these technologies. Full article