Search Results (4,328)

Background: Academic performance is related to cognitive functions and satisfied physiological needs such as proper sleep, a factor frequently overlooked by university students. Our aim was to investigate sleep-related variables, cognitive performance and stress level measured by heart rate variability among university students. Methods: A novel psychophysiological measurement system was used for data collection in which a screen-adapted questionnaire was used to collect data on sleep; gamified versions of standard psychological tests were used to assess cognitive performance, and ECG data were recorded by a wearable ECG sensor, all synchronized by a software. University students volunteered for anonymous testing that lasted approximately one hour. Results: Of the 107 students (mean age: 22.2 years, SD ± 2.22; 52% female), those who reported being well-rested achieved significantly higher overall cognitive performance (p = 0.024). Sleep duration did not correlate with cognitive performance but longer sleep duration was associated with feeling rested (rho = 0.326; p < 0.001). Cognitive performance showed significant association with two HRV parameters such as the Baevsky Stress Index (r = 0.195), higher values of which reflect higher autonomic stress load. Significant negative relation was found between cognitive performance and RMSSD (r = −0.195), another HRV parameter, higher values of which allude to higher parasympathetic activity (p = 0.050 for both). These findings suggest a link between mild arousal and performance. Conclusions: Being rested and lower autonomic stress load are positively correlated with cognitive performance. The novel psychophysiological measurement system integrating subjective and objective measurements of cognitive and physiological functions is feasible for assessing cognitive functions and stress levels in students. Full article

Oral wound healing is a robust process; however, complications from surgery, systemic diseases, and aging can impair healing. While some treatments exist, regenerative therapies to promote mucosal wound healing remain limited. In recent years, there has been a significant rise in FDA-approved cell-based therapies; however, extracellular vesicles represent an emerging cell-free alternative that may mitigate risks associated with cellular therapies, including tumorigenesis and immunogenicity. These lipid-encapsulated nanovesicles can deliver therapeutic cargo, such as proteins, lipids, nucleic acids, or drugs, to the wound site. Extracellular vesicles can be derived from mesenchymal stromal cells, immune cells, bodily fluids, or bacteria, and engineered through genetic modification, preconditioning, or direct cargo loading to enhance therapeutic potency. Furthermore, advanced delivery platforms, including hydrogels, microneedles, and aerosols, allow for sustained and localized EV delivery to the oral wound site. This review examines differences between cutaneous and oral wound healing; factors that impair oral repair; extracellular vesicle sources and engineering strategies; and delivery strategies for developing EV-based therapeutics for oral wound healing. Full article

Kaposi’s Sarcoma-associated herpesvirus (KSHV) and Epstein–Barr virus (EBV) are oncogenic gammaherpesviruses with high prevalence in sub-Saharan Africa. Both viruses are typically acquired during childhood, establishing lifelong latency. While viral reactivation into the lytic cycle has been mainly studied in adult HIV-infected populations—and more recently in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infection—the dynamics of KSHV and EBV infection in children remain poorly understood. Here, we characterize pediatric patients (n = 175; median age 4.6 years; IQR 2.0–8.3) presenting with inflammatory conditions during the COVID-19 pandemic in South Africa (from July 2020 to February 2024). Including a healthy, non-inflammatory control group, we found widespread exposure to SARS-CoV-2 (70.9% seropositivity), with 72.6% of the children being seropositive for EBV and 19.4% for KSHV. There were no significant differences in seroprevalence between children with inflammatory conditions and healthy controls for any of these viruses, although SARS-CoV-2 antibody titers were significantly higher in the inflammatory group, while EBV immune responses were lower in children presenting with inflammation. Among the KSHV-seropositive children, no active viremia was detected (as determined by the absence of viral DNA in the peripheral blood). In contrast, 34.4% of EBV-seropositive children had detectable EBV viral load, with a modestly higher proportion in the inflammatory group. However, EBV viral load levels were comparable between children diagnosed with Multisystem Inflammatory Syndrome in Children (MIS-C), Kawasaki Disease (KD), and other inflammatory conditions. Logistic regression analyses revealed that increasing age was significantly associated with higher risk of SARS-CoV-2 and EBV seropositivity, but not KSHV. Notably, the risk of EBV DNA detection in the peripheral blood decreased with age. In summary, this study suggests effective immunological control of gammaherpesvirus infections in HIV-negative paediatric patients, even in the presence of inflammatory conditions that might otherwise trigger viral reactivation. Full article

Low back pain is common and negatively impacts quality of life and workplace productivity. However, few studies have focused on small- and medium-sized enterprises (SMEs) where risk factors are prevalent. This cross-sectional study examined the association and structural relationships between physical and social factors in low back pain among Japanese SME workers. We analyzed survey data collected between April 2021 and August 2022 from 762 SME workers aged 18–65 years in Shimane, Japan, to assess acute (less than 3 months) and chronic low back pain using a self-reported questionnaire. Workplace physical (physical load) and social (stress of interpersonal relations) factors were measured using a brief job stress-related questionnaire. Associations between workplace factors and acute and chronic low back pain were evaluated using multivariable, multinomial logistic regression. Among the 762 workers, 50.9% and 7.3% reported acute and chronic low back pain, respectively. The odds ratio (OR) for acute pain was 2.08 for ‘Very much so’ in those with a high physical load. Compared with those with low interpersonal stress, the OR for chronic pain was 2.20 for medium stress and 2.82 for high stress. Reducing physical workloads may mitigate acute low back pain, while lowering interpersonal stress at work may reduce chronic low back pain. Future studies should investigate whether improving workplace physical and social factors is longitudinally effective. Full article

Saliva is essential for maintaining oral health, and conditions like hyposalivation increase the risk of diseases. To address this, artificial saliva (AS) formulations incorporated with antimicrobials have been proposed. This study aimed to evaluate the antimicrobial activity and determine the minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of AS formulations containing nystatin (Nys), chlorhexidine diacetate 98% (Chx), and silver nanoparticles (AgNp) against Candida albicans biofilm. The fungistatic and fungicidal properties of six groups (AS; AS + AgNp 2 mM; AS + AgNp 4 mM; AS + AgNp 6 mM; AS + Nys; AS + Chx) were assessed using the XTT colorimetric assay. Additionally, 35 denture base heat-polymerized acrylic resin specimens were prepared and treated with the antimicrobials, serving as substrates for C. albicans biofilm development over 3, 6, and 12 h. Biofilm growth was quantified by CFU/mL counting. All analyses were performed with a significance level of p < 0.05. Results demonstrated fungal load inhibition and a reduction in metabolic activity across all experimental groups (p < 0.05). Notably, AS + Nys, AS + Chx, and AS + AgNp 6 mM exhibited similar and significant inhibitory effects against C. albicans biofilm. Full article

This comprehensive review examines hierarchical control principles and frameworks for grid-connected microgrids operating in environments prone to load shedding and under demand response. The particular emphasis is on South Africa’s current electricity grid issues, experiencing regular planned and unplanned outages, due to numerous factors including ageing and underspecified infrastructure, and the decommissioning of traditional power plants. The study employs a systematic literature review methodology following PRISMA guidelines, analysing 127 peer-reviewed publications from 2018–2025. The investigation reveals that conventional microgrid controls require significant adaptation to address the unique challenges brought about by scheduled power outages, including the need for predictive–proactive strategies that leverage known load-shedding schedules. The paper identifies three critical control layers of primary, secondary, and tertiary and their modifications for resilient operation in environments with frequent, planned grid disconnections alongside renewables integration, regular supply–demand balancing and dispatch requirements. Hybrid optimisation approaches combining model predictive control with artificial intelligence show good promise for managing the complex coordination of solar–storage–diesel systems in these contexts. The review highlights significant research gaps in standardised evaluation metrics for microgrid resilience in load-shedding contexts and proposes a novel framework integrating predictive grid availability data with hierarchical control structures. South African case studies demonstrate techno-economic advantages of adapted control strategies, with potential for 23–37% reduction in diesel consumption and 15–28% improvement in battery lifespan through optimal scheduling. The findings provide valuable insights for researchers, utilities, and policymakers working on energy resilience solutions in regions with unreliable grid infrastructure. Full article

Background: Spondylolysis is a stress fracture of the pars interarticularis, most common in adolescents and athletes involved in sports requiring repetitive spinal loading, extension, and rotation. The condition is often underdiagnosed due to delays in presentation and diagnosis, particularly among non-orthopedic providers. Aims: This review aims to summarize the current understanding of spondylolysis, focusing on its etiology, diagnosis, management strategies, and identify gaps in research for future exploration. Methods: A structured literature search was conducted in PubMed to identify studies relevant to pediatric and adolescent spondylolysis, spondylosis, and spondylolisthesis, particularly in the context of athletic injuries. The initial search yielded 143 citations. Applying filters for English language publications within the past five years reduced this to 125 citations. Limiting to populations that were aged 18 years and under returned 50 studies. After screening the titles and abstracts, 12 non-specific or irrelevant articles (including letters to the editor) were excluded, leaving a final dataset of 38 articles for detailed review. In addition, foundational and landmark studies outside this window were included to provide historical and conceptual context, bringing the total evidence base to 50 papers. Findings: Spondylolysis most commonly affects the L5 vertebra, with a higher incidence in male athletes. Conservative treatments like physical therapy and bracing are effective, especially when initiated early. However, the efficacy of bracing remains debated, with limited evidence on long-term clinical benefits. Surgical intervention is considered for severe or non-responsive cases. Diagnostic methods, including CT and MRI, are preferred, with emerging techniques like ultrasound showing potential for non-ionizing, cost-effective, early detection. Implications: Early diagnosis and treatment are crucial for preventing progression to spondylolisthesis. While conservative treatments often yield favorable outcomes, more research is needed to compare the effectiveness of bracing and pharmacological interventions. Future studies should focus on long-term outcomes, cost-effective, non-ionizing diagnostic methods, and the role of emerging therapies like regenerative medicine. A multi-disciplinary approach is vital for optimal patient care, particularly in young athletes. Full article

Geopolymer mortars were produced from construction and demolition waste using a binary binder of recycled brick powder/recycled concrete powder (RBP/RCP = 70/30 wt%), activated with a hybrid alkaline solution (NaOH/Na₂SiO₃/KOH) and reinforced with sisal fibres at 0–2 wt%. Mechanical performance (compression and three-point bending) and microstructure–phase evolution (XRD, FTIR, SEM-EDS) were assessed after low-temperature curing. Sisal addition delivered a strength–toughness trade-off with a reproducible optimum at ~1.0–1.5 wt%; at 2.0 wt%, fibre clustering and connected porosity reduced the effective load-bearing section, penalising flexure more than compression. Microstructural evidence indicates coexistence and co-crosslinking of N-A-S-H and C-(A)-S-H gels—enabled by Ca from RCP—leading to matrix densification and improved fibre–matrix anchorage. Fractographic features (tortuous crack paths, bridging, and extensive pull-out at ~1.5 wt%) are consistent with an extended post-peak response and higher fracture work without compromising early-age strength. This study achieves the following: (i) it identifies a practical reinforcement window for sisal in RBP/RCP geopolymers, (ii) it links gel chemistry and interfacial phenomena to macroscopic behaviour, and (iii) it distils processing guidelines (gradual addition, workability control, gentle deaeration, and constant A/S) that support reproducibility. These outcomes provide a replicable, low-embodied-CO₂ route to fibre-reinforced geopolymer mortars derived from CDW for non-structural and semi-structural applications where flexural performance and post-peak behaviour are critical. Full article

Work-related musculoskeletal disorders (MSDs) remain a global occupational health priority, with recognized limitations in current point-in-time assessment methodologies. This research extends prior computer vision ergonomic assessment approaches by implementing biological proprioceptive feedback principles into a continuous, real-time monitoring system. Unlike traditional periodic ergonomic evaluation methods such as “Rapid Upper Limb Assessment” (RULA), our bio-inspired system translates natural proprioceptive mechanisms—which enable continuous postural monitoring through spinal feedback loops operating at 50–150 ms latencies—into automated assessment technology. The system integrates (1) markerless 3D pose estimation via MediaPipe Holistic (33 anatomical landmarks at 30 FPS), (2) depth validation via Orbbec Femto Mega RGB-D camera (640 × 576 resolution, Time-of-Flight sensor), and (3) proprioceptive-inspired alert architecture. Experimental validation with 40 adult participants (age 18–25, n = 26 female, n = 14 male) performing standardized load-lifting tasks (6 kg) demonstrated that 62.5% exhibited critical postural risk (RULA ≥ 5) during dynamic movement versus 7.5% at static rest, with McNemar test $p<0.001$ (Cohen’s $h=1.22$, 95% CI: 0.91–0.97). The system achieved 95% Pearson correlation between risk elevation and alert activation, with response latency of $42.1\pm 8.3$ ms. This work demonstrates technical feasibility for continuous occupational monitoring. However, long-term prospective studies are required to establish whether continuous real-time feedback reduces workplace injury incidence. The biomimetic design framework provides a systematic foundation for translating biological feedback principles into occupational health technology. Full article

In recent years, metal nanoclusters (NCs) with atomic-scale precision have emerged as novel photosensitizers for light energy conversion in metal cluster-sensitized semiconductor (MCSS) systems. However, conventional NCs often suffer from photodegradation after binding with semiconductors, limiting their long-term catalytic stability. Modifying NCs via single-atom doping provides an effective strategy to tailor their interfacial charge transfer behavior. In this study, PtAg₂₈ NCs were synthesized by doping Pt single atoms into Ag₂₉ NCs and subsequently loaded onto TiO₂ via electrostatic adsorption to construct composite photocatalysts. Systematic investigations revealed that Pt doping significantly enhances light absorption and promotes the formation of a direct Z-scheme heterojunction. The optimized PtAg₂₈/TiO₂ composite exhibits effective suppression of charge recombination. This enhanced charge separation efficiency, driven by pronounced band bending at the interface, leads to a remarkable hydrogen evolution rate of 14,564 μmol g⁻¹ h⁻¹. This work demonstrates the critical role of single-atom doping in regulating the photophysical properties of metal NCs and offers a feasible approach for designing highly efficient and stable metal-cluster-based photocatalytic systems. Full article

Background: The characteristics and prognosis of HIV-associated Kaposi sarcoma (KS) among people living with HIV (PLWH), and their association with HHV-8 viral load are not well understood in Japan. Methods: We conducted a retrospective study of PLWH diagnosed with KS at Tokyo Medical University from 2000 to 2023. Results: Seventy cases of KS were identified; HHV-8 viral load data were available for twenty-three of these cases. The median age was 43 years (interquartile range [IQR], 11 years). The median HIV viral load at diagnosis was 150,000 copies/mL (IQR, 560,000 copies/mL). The median CD4 count was 76.0/μL (IQR, 157/μL). Lesions other than those of the skin were observed in the gastrointestinal tract (nine cases, 39.1%), oropharynx (three cases, 13.0%), and bronchial/lung (two cases, 8.7%). The median HHV-8 viral load was 0.0 copies/10⁶ WBC (IQR, 1500 copies/10⁶ WBC). Among the nine deceased PLWH, KS inflammatory cytokine syndrome (KICS) was diagnosed in five PLWH. Older age (≥50 years) and a high HHV-8 viral load (>615 copies/10⁶ WBCs) were significantly associated with worse survival. Conclusion: A high HHV-8 viral load may be a risk factor for mortality in PLWH with KS. Notably, all PLWH diagnosed with KICS in this study died, underscoring the poor prognosis associated with this condition. Full article

The operational reliability of Insulated Gate Bipolar Transistor (IGBT) modules in demanding transportation applications, such as traction systems, is critically challenged by solder layer and bond wire failures under cyclic thermal stress. To address this, this paper proposes a novel health monitoring framework that innovatively synergizes micro-scale spatial thermal analysis with microsecond electrical dynamics inversion. The method requires only non-invasive temperature measurements on the module baseplate and utilizes standard electrical signals (load current, duty cycle, switching frequency, DC-link voltage) readily available from the converter’s controller, enabling simultaneous diagnosis without dedicated voltage or high-bandwidth current sensors. First, a non-invasive assessment of solder layer fatigue is achieved by correlating the normalized thermal gradient ($\nabla T_{\mathrm{P}}$) on the baseplate with the underlying thermal impedance ($Z_{\mathrm{JC}}$). Second, for bond wire aging, a cost-effective inversion algorithm estimates the on-state voltage ($V_{\mathrm{ce},\mathrm{on}}$) by calculating the total power loss from temperature, isolating the conduction loss ($P_{\mathrm{cond}}$) with the aid of a Foster-model-based junction temperature ($T_{\mathrm{J}}$) estimate, and finally computing $V_{\mathrm{ce},\mathrm{on}}$ at a unique current inflection point ($I_{\mathrm{C},\inf }$) to nullify $T_{\mathrm{J}}$ dependency. Third, the health states from both failure modes are fused for comprehensive condition evaluation. Experimental validation confirms the method’s accuracy in tracking both degradation modes. This work provides a practical and economical solution for online IGBT condition monitoring, enhancing the predictive maintenance and operational safety of transportation electrification systems. Full article

The present study intends to evaluate the ratcheting of ER9 wheel medium carbon steel and austenitic steel samples at room and elevated temperatures subjected to uniaxial loading cycles through the use of the Ahmadzadeh–Varvani (A–V) kinematic hardening rule. The A–V framework incorporated an exponential function in the dynamic recovery term to account for the dynamic strain aging (DSA) phenomenon at temperatures where solute atoms and moving dislocations showed increased interaction. Within the DSA domain at 573K for ER9 wheel steel samples, and at 423K for austenitic steel samples, the collision of carbon and nitrogen solute atoms with moving dislocations resulted in the materials hardening, and promoted the yield strength. The Voyiadjis–Song–Rusinek (VSR) multivariable model was used to capture the evolution of yield strength with temperature. The predicted ratcheting results within the DSA temperature domain were in close agreement with those of measured values. Full article

Background: Catechol-O-methyltransferase (COMT) catalyzes catecholamine O-methylation and contributes to dopamine turnover, potentially influencing levodopa requirements in Parkinson’s disease (PD). We evaluated whether the Gothelf COMT haplotype—and its constituent variants rs2075507, rs4680 (Val158Met), and rs165599—differ in frequency between PD cases and controls. We then tested associations between these variants and clinical phenotypes, with a prespecified focus on levodopa equivalent daily dose (LEDD). Finally, we examined whether haplotype structure and allele-specific context (e.g., background-dependent effects) help explain observed genotype–phenotype relationships in the PD cohort. Aim: Analysis of the rs2075507, rs4680 and rs165599 at individual and haplotype level between control and diseased groups. Furthermore, analysis of association of individual SNPs or haplotype level with clinical outcomes. Subjects and methods: Fifty-five individuals with Parkinson’s disease (PD) and fifty-three neurologically healthy controls were enrolled at a single center. Genomic DNA was isolated from peripheral blood, and three COMT variants—rs2075507 (promoter), rs4680/Val158Met (coding), and rs165599 (3′UTR)—were genotyped by Sanger sequencing. Allele, genotype, and tri-marker haplotype frequencies were estimated, and case–control differences were evaluated. Within the PD cohort, associations with clinical outcomes—primarily levodopa equivalent daily dose (LEDD)—were analyzed using multivariable linear models. Statistical tests were two-sided, with multiplicity control as specified in the corresponding tables. Results: The rs2075507 polymorphism showed a robust additive association with LEDD; each A allele predicted higher dose (LEDD ≈ +1331 mg/day, p = 0.001) after adjusting for age and sex. The tri-haplotype test did not show significant association with LEDD. Nevertheless, rs2075507 SNP strongly marked downstream backgrounds: in AA carriers, rs4680–rs165599 haplotypes were enriched for Val (G) and rs165599-G; in GG carriers, for rs165599-A with mixed Val/Met; and GA was A-loaded at both loci. Exact tests confirmed that AA and GG differed in rs4680–rs165599 composition, whereas GA vs. GG was not significant. Conclusions: The promoter variation at rs2075507 may represent the genetic contributor to levodopa dose requirements when modeled with SNP–SNP interactions, with its effect is modified mostly by rs165599 polymorphism. Tri-haplotypes do not independently predict LEDD. The rs4680 (coding) and rs165599 (3′UTR) context appears to fine-tune rather than determine dosing needs, mainly via interaction with rs2075507 SNP. Full article

Cleaning historical silk textiles is a particularly sensitive operation that requires precise control to prevent mechanical or chemical damage. In this study, we investigate using flexible PVA–borax-based gels to remove soot from silk, i.e., polyvinyl alcohol–borax (PVA-B) gels and polyvinyl alcohol–borax–agarose double network gels (PVA-B/AG DN) loaded with different cleaning agents—namely, 30% ethanol and 1% Ecosurf EH-6—in addition to plain gels loaded with water. These gel formulations were tested on simplified model systems (SMS) and were applied using two methods: placing and tamping. The cleaning results were compared with a traditional contact-cleaning approach; micro-vacuuming followed by sponging. Visual inspection, 3D opto-digital microscopy, colorimetry, and machine-learning-assisted (ML) soot counting were exploited for the assessment of cleaning efficacy. Rheological characterization provided information about the flexibility and handling properties of the different gel formulations. Among the tested systems, the DN gel containing only water, applied by tamping, was easy to handle and demonstrated the highest soot-removal effectiveness without leaving residues, as confirmed by micro-Fourier Transform Infrared (micro-FTIR) analysis. Scanning electron microscope (SEM) micrographs proved the structural integrity of the treated silk fibers. Overall, this work allows us to conclude that PVA–borax-based gels offer an effective, adaptable, and low-risk cleaning strategy for historical silk fabrics. Full article