Search Results (49,359)

Glaucoma is a complex condition with an unknown exact cause, but it involves progressive damage to the optic nerve. This damage is primarily driven by high eye pressure, poor blood flow, and oxidative stress, a process linked to cell ageing and inflammation that harms the retina. Recent research highlights that these issues stem from structural changes in the eye’s drainage system and visual pathways, which can be analysed through the lens of engineering thermodynamics. This study proposes a thermal explanation for the physiological processes linking ocular behaviour to inflammatory ion flux alterations. We develop a thermal model demonstrating that temperature increases are tied to the mechanical work necessary for maintaining water flux in the anterior ocular chamber. We show that these changes alter the membrane potential and tissue pH, resulting in elevated intraocular pressure. By clarifying the temperature–pressure effect, this research establishes a theoretical framework to study the developments of future glaucoma therapies. Full article

We perform stochastic simulations of the Hodgkin–Huxley and Morris–Lecar models with different numbers of ion channels in order to describe the effects of periodic electrical driving on spike rates and the regularity of spiking in a single neuron. For stochastic modeling, we use an efficient method that reduces the piecewise-deterministic Markov process of the membrane potential evolution to an ordinary differential equation between random opening and closing events. To characterize a regular component in the resulting voltage time series, we adopt a Wiener order parameter based on the autocorrelation function. We show that the effect of ion channel stochasticity on the spike rate is stronger at lower external force frequencies. The regular component of neural activity exhibits resonant-like behavior as a function of the driving frequency, with a maximum in the beta range. Full article

Periodontitis is a biofilm-associated inflammatory disease that still requires effective local non-antibiotic antibacterial strategies. In this study, we developed a protonated defect-engineered atomic-layered graphitic carbon nitride nano-system (PVCN) for visible light photodynamic antibacterial therapy. Defect engineering was used to improve visible light absorption and photodynamic activity, while protonation introduced a positively biased surface potential to strengthen bacteria–material interactions and enhance interfacial antibacterial efficacy. Under visible light irradiation, PVCN showed increased ROS production, stronger bacterial adhesion, and rapid killing activity against both Staphylococcus aureus and Escherichia coli, with bactericidal efficiency above 95%. PVCN also disrupted S. aureus biofilms and induced membrane damage, intracellular content leakage, and metabolic suppression. Atomic force microscopy and omics analyses further supported enhanced bacterial adsorption as an important contributor to the improved antibacterial efficacy of PVCN. In vitro assays demonstrated preliminary cytocompatibility and hemocompatibility. In a ligature-induced mouse periodontitis model, PVCN reduced bacterial burden, alleviated inflammation, and attenuated alveolar bone loss. These results support PVCN as a promising photodynamic antibacterial material with preliminary therapeutic potential in experimental periodontitis, and highlight bio-interface regulation as a useful strategy for designing efficient carbon nitride-based photodynamic antibacterial materials. Full article

Thin rectangular plates, due to their small thickness relative to length and width and their high strength-to-weight ratio, are widely used in structural elements such as ship hulls, bridge decks, and aircraft wings. They are prone to nonlinear buckling under compressive forces, especially under biaxial in-plane compressive loading with large displacements, where linear theories often fail and membrane stresses complicate analysis. This study aimed to formulate a general mathematical equation for buckling analysis of thin rectangular isotropic plates with large displacements subject to biaxial in-plane forces using the Ritz potential energy functional method, and incorporates both geometric and material nonlinearities. Based on the formulated general equation, a specific equation for an all-round simply supported (SSSS) plate was developed using polynomial displacement shape function to determine the stiffness characteristics. Numerical values for critical buckling and post-buckling loads under biaxial compression for a square plate case were obtained. To validate these results, a comparison with values in the literature was made and the results show high consistency. The uniaxial buckling deviations ranged 0.047–0.10%, while undeformed biaxial buckling coefficients across varying aspect ratios and loading ratios (n = Ny/Nx) showed near-zero differences. From the two studies used for comparison, the maximum deviation is 24.42% and the minimum deviation is 1.12%. This indicates that the new model is adequate. Also, the adequacy of this new equation can be judged based on the simplicity of the formulation, and the closed agreement of the obtained numerical results with established results in the literature. This research enhances theoretical understanding of nonlinear buckling in thin plates and offers practical insights for improving structural reliability and efficiency in civil, mechanical, aerospace, and marine engineering. Therefore, the conclusion is that the model is suitable for buckling and post-buckling analysis of thin rectangular isotropic plates. Full article

This study aimed to investigate the regulatory effect and cryoprotective mechanism of melatonin (MT) on the physiological functions of Lactobacillus plantarum FQR during freezing and freeze-drying. Results indicated that the addition of 5 mg/mL MT as a cryoprotectant maximized the freeze-drying survival rate to 32.04 ± 2.14%. MT effectively alleviated low-temperature and freeze-drying stress by reducing extracellular alkaline phosphatase activity, enhancing intracellular lactate dehydrogenase activity, and decreasing extracellular β-galactosidase activity without significant differences. Higher survival rates in defining medium further suggested that MT reduced damage to cell wall and membrane structures during lyophilisation, decreased membrane permeability, and preserved cellular physiological functions. In addition, MT supported cellular energy metabolism and protein synthesis, enhanced transmembrane potential to facilitate ATP transport, and helped maintain intracellular and extracellular pH balance. The prepared freeze-drying protectant containing 69.80 mg/mL exopolysaccharides (EPS) and 4.25 mg/mL MT showed better protective effects than the control group. MT also increased bound water content, lowered the freezing point of the solution, and inhibited ice crystal formation. Transcriptomic analysis revealed that amino acid biosynthesis, amino acid metabolism, and ABC transport systems were the primary pathways affected by MT treatment. These findings demonstrate that MT improves freeze-drying tolerance by maintaining membrane integrity, regulating cellular metabolism, and enhancing oxidative stress resistance. Given its natural biosynthetic origin, generally recognized as safe (GRAS) status, and absence of residual solvents or allergenic proteins, MT can be safely considered for incorporation into food and nutraceutical products. This study underscores the practical relevance of MT as a functional component in compound cryoprotectants, providing a feasible strategy to enhance the viability, stability, and industrial applicability of Lactobacillus plantarum during freeze-drying and storage. Full article

Peptide therapeutics have emerged as a versatile class of biomolecules bridging the gap between small-molecule drugs and large biologics. Advantages of such molecules include high target specificity, potent bioactivity and reduced off-target toxicity. Despite these, broader clinical translation remains constrained by inherent limitations like poor metabolic stability, rapid renal clearance, limited membrane permeability and scalable synthesis. This review aims to systematically integrate advances in peptide science across natural discovery, synthetic methodologies, structural engineering, and translational delivery systems, while identifying critical research gaps hindering clinical adoption. We highlight diverse natural sources of bioactive peptides, including plant- (lunasin), animal- (Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP)), microbial- (nisin and cyclosporine), marine- (dolastatins) and venom-derived (chlorotoxin and ω-conotoxin MVIIA (ziconotide)) agents. Advances in solid-phase peptide synthesis (SPPS), green chemistry, and catalytic strategies are discussed alongside emerging in silico approaches, including artificial intelligence-driven sequence design and molecular modeling. Structural modifications such as cyclization, hydrocarbon stapling, PEGylation, and lipidation are critically evaluated for their role in enhancing pharmacokinetic and pharmacodynamic properties. Furthermore, nanoformulation strategies, including self-assembling peptides and cell-penetrating systems, are examined for their potential to overcome biological barriers. Importantly, this review identifies key unresolved challenges, including the lack of predictive models for peptide delivery systems, safety concerns associated with long-term modifications, and limited in vivo validation of naturally derived peptides. Addressing these gaps through integrated computational and experimental approaches will be essential for advancing next-generation peptide therapeutics. Collectively, this work provides a comprehensive framework for the rational design and translation of peptide-based precision medicines. Full article

This study aimed to establish a rapid analytical method for the determination of 69 pesticide residues in Platycodonis Radix using GC-MS/MS and UHPLC-MS/MS, as well as carry out a dietary risk assessment on 42 batches of Platycodonis Radix samples collected from different geographical origins. Samples were prepared using the QuEChERS method, followed by high-speed centrifugation and membrane filtration, and the target pesticides were analyzed in selected reaction monitoring (SRM) mode via GC-MS/MS and in multiple reaction monitoring (MRM) mode via UHPLC-MS/MS. Among the 42 tested batches of Platycodonis Radix samples, 3 out of 27 pesticide compounds were detected via GC-MS/MS screening, while only 1 pesticide compound was positive from the 42 compounds determined via UHPLC-MS/MS, and the risk assessment results demonstrated that both chronic and acute dietary exposure risks of all detected pesticides were considerably lower than 1. Full article

Sustainable energy technologies like the fuel cell have been explored as potential substitute energy sources to lessen pollution and reliance on fossil fuels. At the very core of fuel cells are ionomer membranes, particularly used in proton exchange membrane fuel cells (PEMFCs) and other electrochemical devices such as electrolyzers. This research aimed to study the morphological and structural changes of ionomer membranes in the presence of single solvents. The ionomer membranes were partially dissolved in water (polar protic solvent) and dimethyl sulfoxide (polar aprotic solvent) and analyzed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and electrochemical impedance spectroscopy (EIS). The results showed that water, being a polar protic solvent, interacted not only with the hydrophilic sulfonic acid regions of the membranes but also with the hydrophobic fluorocarbon backbone as seen in the EDX results. On the other hand, DMSO, which is a polar aprotic solvent, caused more visible changes in both structure and surface appearance. By examining these relationships more closely, this research deepened our understanding of how single solvents affect ionomer membranes to improve ionomer membrane fabrication methods. Full article

Microbial inoculation is widely used to improve composting performance, yet its effectiveness hinges on inoculum composition, substrate characteristics, and composting technology, which remain poorly understood. This study compared single versus mixed inoculants across different substrates and assessed their interactions with biochar amendment and nanomembrane covering, focusing on organic matter transformation, inorganic nutrient dynamics, and biological pollution control. Mixed inoculation significantly improved heating performance in cattle manure compost compared to single strains (p < 0.05) and sustained thermophilic conditions in sludge-sawdust compost, but showed limited impact in chicken manure-sludge compost. It reduced humic acid (HA) accumulation in chicken manure-sludge compost (14.29% to −39.28%) while increasing HA content in sludge-sawdust compost (3.55–5.41 g/kg, p < 0.05). Inorganic nitrogen retention was enhanced; specifically NO₃⁻-N concentrations rose by 175.1–222.6% in the chicken manure-sludge and by 6.7–17.9% in the sludge-sawdust compost. Microbial community analysis indicated enrichment of inoculant strains during the thermophilic phase, supporting nitrogen conservation and humification. However, inoculation increased potential pathogenic bacteria by over 51.2% across all composts and enriched predicted antibiotic resistance genes (ARGs) by 9.9–22.96% in chicken manure-sludge compost, while reducing the membrane covering’s inhibitory effect on predicted ARGs (rebound by 29.5%). Moreover, we found that the predicted ARG profiles, derived from 16S-based PICRUSt2 functional inference, covaried strongly with microbial community structure, with environmental factors such as organic carbon shaping predicted ARG dynamics mainly through indirect effects on microbial communities. These findings highlight that while mixed inoculation boosts composting efficiency, it also raises biosafety concerns. Thus, a comprehensive evaluation integrating organic, inorganic, and biological perspectives is essential before promoting thermophilic inoculants. Full article

Glucose is the principal energy substrate for the brain. Hypo- and hyperglycemic episodes frequently occur in senescent people, contributing to functional and structural impairment of brain neurons and causing cognitive deficits in this population. In this study, we investigate whether long-term changes in the extracellular concentration of glucose affect viability and transmitter functions of septum-derived SN56 cholinergic neuronal cells through alterations in acetyl-CoA availability. Cells with low cholinergic expression (NCs) and cAMP/retinoic acid-induced high cholinergic expression (DCs) were investigated. Hypoglycemia brought about similar (approximately 20–30%) decreases in pyruvate dehydrogenase complex (PDHC) and ATP-citrate lyase (ACLY) activities and a 65% decline in lactate dehydrogenase (LDH) activity in NCs and DCs. Choline acetyltransferase (ChAT) and LDH activities in DCs were about 3–8 and 1.7–2.4 times higher than in NCs over the tested glucose concentration range, respectively. DCs appeared to be more resistant than NCs to hypoglycemia, as evidenced by lower glucose IC₅₀ values for cell count and intracellular LDH activity. On the other hand, some of functional properties of DCs, such as the cholinergic phenotype and their plasma membrane functions (trypan blue exclusion, TB+), were found to be more sensitive to hypoglycemia than those of NCs, as demonstrated by the higher IC₅₀ for glucose in DCs. Acetyl-CoA levels in DCs were 40% lower than in NCs, and decreased by about 25% with increasing hypoglycemia in both cell types. The cytotoxic effects of amyloid-β_25–35 (Aβ) and sodium nitroprusside (SNP; NO generator) were also tested. In 25 mM glucose medium, these toxic compounds exerted greater detrimental effects on DCs than on NCs. In contrast, in 1 mM glucose, more evident cytotoxicity of SNP and Aβ was observed in NCs. These data suggest that the higher rate of glycolysis in differentiated cholinergic septal neurons may be a protective mechanism against hypoglycemia. Full article

Purpose: To evaluate the anatomical and functional efficacy of photobiomodulation (PBM) therapy in patients with dry age-related macular degeneration (AMD) and to investigate structural predictors of visual response. Methods: This retrospective study included 47 eyes of 30 patients with dry AMD treated with PBM. Best-corrected visual acuity (BCVA) was recorded as Early Treatment Diabetic Retinopathy Study (ETDRS) letter score, and visual change (ΔBCVA) was calculated. Spectral-domain optical coherence tomography parameters—central retinal thickness (CRT), central macular volume (ETDRS 9-subfield central zone), and photoreceptor layer integrity (external limiting membrane [ELM], ellipsoid zone [EZ], and interdigitation zone [IZ])—were assessed pre- and post-treatment. Age-Related Eye Disease Study (AREDS) stage was graded per eye. Because both eyes from some patients were included, generalized estimating equation (GEE) models with patient-level clustering were used to account for inter-eye correlation. Effect estimates were reported as unstandardized coefficients with 95% confidence intervals. Results: Visual acuity improved following PBM therapy, with mean ETDRS letter scores increasing from 75.0 ± 14.1 to 78.0 ± 12.1 letters. In the GEE model accounting for patient-level clustering, the estimated mean gain was 2.97 ETDRS letters (95% CI: 1.15 to 4.79; p = 0.001). Mean CRT showed no significant change following PBM therapy (210.32 ± 48.61 µm vs. 211.23 ± 50.27 µm; GEE estimate: +0.91 µm; 95% CI: −5.52 to 7.35; p = 0.780). Central macular volume likewise remained stable (0.1913 ± 0.030 vs. 0.1919 ± 0.033 mm³; GEE estimate: +0.0006 mm³; 95% CI: −0.0054 to 0.0067; p = 0.836). Photoreceptor layer integrity demonstrated limited structural change, with no significant time effect for EZ or IZ integrity in binary GEE models and no observed pre–post change in ELM integrity. In multivariable GEE analysis, baseline BCVA (p < 0.001), ELM integrity (p < 0.001) and central macular volume (p = 0.041) were associated with change in ETDRS letter score, whereas AREDS category, EZ integrity, and IZ integrity were not. Conclusions: PBM therapy demonstrated limited short-term anatomical change but variable functional outcomes in dry AMD. Baseline BCVA emerged as the primary determinant of visual response, suggesting that treatment benefit may be influenced predominantly by pre-treatment functional reserve. Full article

Background/Objectives: The aquaculture industry represents a fundamental food sector. One of the main limiting factors for this sector is related to bacterial diseases, for which antibiotics have been widely used worldwide for decades. In recent years, a more conscious approach to the use of antimicrobials within the framework of the One Health approach has increased the need for alternatives capable of helping with disease management while avoiding the onset of antimicrobial resistance phenomena. Antimicrobial peptides, which have a broad spectrum of action against pathogens, are a promising solution. Methods: In this work, we investigated the capability of three peptides (Trematocine, Chionodracine, and Cnd-m3) isolated from Antarctic fish to target bacterial and viral pathogens affecting aquaculture. Successively, we investigated their cytotoxicity versus a continuous embryonic cell line (DLEC) derived from European sea bass and their haemolytic activity against fish erythrocytes. Moreover, we evaluated their immunomodulatory effect. Results: Regarding antibacterial properties, Cnd-m3 was identified as the best peptide, demonstrating good bactericidal and bacteriostatic activity against various bacterial strains, including Lactococcus garvieae. Concerning this bacterium, ANS permeability assays showed that the Cnd-m3 peptide has a great ability to interact with its outer membrane, while TEM analysis revealed that the peptide, after destabilization of the cell membrane, interacts with nucleic structures. Considering the antiviral activity, Trematocine was effective against two tested pathogenic enveloped viruses. Moreover, the toxicity of Trematocine and Cnd-m3 was evaluated by investigating their cytotoxicity against a cell line derived from Dicentrarchus labrax and haemolysis against sea bass erythrocytes. Both revealed good selectivity towards pathogens at the lowest concentration. Finally, Cnd-m3 manifested light in vitro immunomodulatory properties. Conclusions: Overall, these data provide a solid basis for future studies assessing the potential applications of two of the tested peptides in aquaculture. Full article

Cryopreservation of gametes is crucial for conserving genetic diversity in livestock and endangered species, but the process can significantly impair sperm quality due to oxidative stress. Our aim was to evaluate the impacts of coenzyme Q10 (CoQ10) supplementation on the in vitro quality of cooled and cryopreserved goat semen. Semen samples collected from six mature Saanen bucks were pooled then diluted with AndroMed^® semen extender to a final concentration of 800 × 10⁶ sperm/mL. Diluted semen was supplemented with 0, 1, 2, 5, 10, and 20 µM CoQ10. Extended semen was either cooled at 4 °C for 72 h or cryopreserved using a Styrofoam box in which the straws were arranged on the freezing rack and placed 4 cm over the liquid nitrogen (LN₂) for 10 min then stored in a LN₂ tank for one-week before being thawed at 37 °C for 30 sec. Sperm quality, including total and progressive motility, sperm kinematics, live sperm %, and sperm membrane integrity, was assessed at 0 h (fresh semen), and 24, 48, and 72 h post-cooling. For post-thaw sperm, we evaluated the same parameters plus acrosome integrity, mitochondrial activity, lipid peroxidation, and sperm ultrastructural changes using scanning electron microscopy (SEM). The pooled semen sample was considered the experimental unit for all treatments. Cooled semen data were analyzed using a General Linear Model (GLM) with univariate analysis, followed by Tukey’s test for multiple comparisons. In contrast, data from frozen–thawed semen were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s test. CoQ10 supplementation at 10 and 20 µM significantly (p < 0.05) improved sperm motility, viability, and membrane integrity in cooled and frozen–thawed semen in comparison with the control group (0 µM CoQ10). Moreover, the same concentrations significantly (p < 0.05) enhanced acrosome integrity, mitochondrial activity, and reduced the percentages of sperm with lipid peroxidation in frozen–thawed semen. Furthermore, 10 and 20 µM CoQ10 significantly mitigated the ultrastructural defects in frozen–thawed spermatozoa. In conclusion, CoQ10 supplementation during the cooling and cryopreservation of dairy goat semen significantly improved sperm quality. Among the tested concentrations, 10 and 20 µM exhibited the most favorable outcomes. Full article

Background/Objectives: Epiretinal membrane (ERM) is a common vitreoretinal disorder characterized by fibrocellular proliferation on the inner retinal surface, often leading to progressive visual impairment. Accurate grading of ERM severity using optical coherence tomography (OCT) is critical for treatment planning and surgical decision-making; however, manual grading is labor-intensive and subjective. This study aims to develop an automated and reliable deep learning-based method for ERM severity classification. Methods: We propose DenseViT-OCT, a hybrid deep learning model that integrates dense convolutional neural networks (CNN) and vision transformers (ViT). The model introduces three key modules: Multi-Scale Dense Feature Aggregation (MDFA) for capturing hierarchical features across multiple spatial scales, Adaptive Feature Calibration (AFC) for enhancing feature discrimination through channel and spatial attention, and Cross-Attention Feature Fusion (CAFF) for enabling bidirectional interaction between convolutional and transformer representations. The model was trained and evaluated on 2195 OCT B-scan images obtained from 397 patients. Results: DenseViT-OCT achieved an overall accuracy of 94.76% on the internal four-class test set, outperforming 19 benchmark models, including ConvNeXt, EfficientNet, ViT, and Swin Transformers. The model demonstrated balanced performance with a macro-averaged precision of 93.76%, recall of 93.22%, F1-score of 93.47%, Cohen’s kappa of 92.62%, and macro-Area Under the Curve (AUC) of 98.95%. Ablation experiments confirmed the contribution of the proposed MDFA, AFC, CAFF, and deep supervision components, with the full model consistently outperforming reduced variants and standalone DenseNet121 and ViT-B/16 backbones. In repeated experiments across five random seeds, DenseViT-OCT also achieved the best mean accuracy (0.9399 ± 0.0052). External validation on the public multicenter OCTDL dataset, performed as binary ERM-versus-normal classification because of label availability, yielded 90.76% accuracy and 97.61% AUC, indicating promising generalization beyond the development cohort. Conclusions: DenseViT-OCT provides a robust framework for automated ERM severity classification from OCT B-scans. The combination of local CNN features, global transformer context, and dedicated fusion modules improves classification performance and yields clinically meaningful error patterns. Although further stage-wise multicenter validation, volumetric OCT analysis, and prospective clinical assessment are required, the proposed method shows promise as a research-oriented decision-support framework for B-scan-level ERM assessment. Full article

To address performance limitations in proton exchange membrane fuel cells (PEMFCs), this work proposes and numerically investigates a cathode gas diffusion layer (GDL) with conical frustum grooves. A systematic comparison is performed across three GDL configurations: a baseline structure without grooves, a design with cylindrical grooves, and the proposed conical frustum grooves. The results demonstrate that the conical frustum grooves effectively enhance liquid water removal, oxygen mass transport, membrane current density, and peak power density. This improvement arises as the grooves expand transport pathways for both liquid water and oxygen, facilitating more robust electrochemical reactions. A parametric analysis is further conducted to evaluate the effects of groove spacing, depth, top radius, and bottom radius. Reduced groove spacing, together with increased groove depth, top radius, and bottom radius, consistently improves water management and oxygen delivery. However, membrane current density and power density do not vary monotonically with groove depth and bottom radius. The optimal values for these two parameters are identified as 0.3 mm and 0.5 mm, respectively. Full article