Search Results (90,317)

This paper presents an integrated study on the design, simulation, manufacturing, and experimental testing of a three-blade tritoroidal propeller compared to a conventional two-blade configuration for small UAVs. The aerodynamic analysis was performed in ANSYS Fluent 2022 R1 using the k–ω SST turbulence model at 6000 rpm, while structural integrity was assessed through FEM simulations in ANSYS Mechanical 2022 R1. Both propellers were fabricated via SLA additive manufacturing using Rigid 4000 resin and evaluated on an RCbenchmark 1585 test stand. The CFD results revealed smoother flow attachment and reduced tip vortex intensity for the tritoroidal geometry, while FEM analyses confirmed lower deformation and a more uniform stress distribution. Experimental tests showed that the tritoroidal propeller produces thrust comparable to the conventional one (within 1%) but at a 58% higher torque, resulting in slightly lower efficiency. However, vibration amplitude decreased by up to 70%, and the SPL was reduced by 0.1–6.2 dB at low and moderate speeds. These results validate the tritoroidal concept as a structurally robust and acoustically efficient alternative, with strong potential for optimization in low-noise UAV propulsion systems. Full article

The objective of this study was to evaluate the effects of sodium butyrate and organic zinc supplementation, alone or combined, on performance, zinc metabolism, blood parameters, and gut health in Holstein calves highly challenged by heat and diarrhea during the pre-weaning and weaning periods. Forty-eight male calves were assigned to one of four treatments: control (CON), SB (3 g/kg of sodium butyrate in dry matter [DM]), OZn (262 mg/kg of organic zinc in DM), or SBOZn (3 g/kg of sodium butyrate and 262 mg/kg of organic zinc in DM). Calves were monitored from days 7 to 63 for feed intake, weight gain, body morphometry, fecal score, and blood parameters. Zinc balance was evaluated from days 45 to 49, and 24 calves were slaughtered on day 64 for jejunal sampling to assess tight junction gene expression. Diarrhea incidence was high (>90%) across groups. Fecal scores varied over time but did not differ between treatments. The OZn and SBOZn groups had higher Zn intake, with greater absorption and retention of the mineral compared to the CON and SB groups. Additionally, the OZn group tended to have higher serum Zn concentrations. SB and OZn, separately or combined, had limited effects and did not consistently improve the performance or health of calves highly challenged during pre-weaning and weaning. Full article

The Czochralski method is the dominant technique for producing power-electronics-grade silicon crystals. At the beginning of the seeding stage, an excessively high (or low) temperature at the solid–liquid interface can cause the time required for the seed to reach the specified length to be too long (or too short). However, the time taken for the seed to reach a specified length is strictly controlled in semiconductor crystal growth to ensure that the initial temperature is appropriate. An inappropriate initial temperature can adversely affect crystal quality and production yield. Accurately evaluating whether the current temperature is appropriate for seeding is therefore essential. However, the temperature at the solid–liquid interface cannot be directly measured, and the current manual evaluation method mainly relies on a visual inspection of the meniscus. Previous methods for detecting this temperature classified image features, lacking a quantitative assessment of the temperature. To address this challenge, this study proposed using the duration of the seeding stage as the target variable for evaluating the temperature and developed an improved multimodal fusion regression network. Temperature signals collected from a central pyrometer and an auxiliary pyrometer were transformed into time–frequency representations via wavelet transform. Features extracted from the time–frequency diagrams, together with meniscus features, were fused through a two-level mechanism with multimodal feature fusion (MFF) and channel attention (CA), followed by masking using spatial attention (SA). The fused features were then input into a random vector functional link network (RVFLN) to predict the seeding duration, thereby establishing an indirect relationship between multi-sensor data and the seeding temperature achieving a quantification of the temperature that could not be directly measured. Transfer comparison experiments conducted on our dataset verified the effectiveness of the feature extraction strategy and demonstrated the superior detection performance of the proposed model. Full article

Effective communication is essential for professional practice, yet medical curricula rarely incorporate systematic, performance-based training. The Sell Yourself!—Presentation Techniques course was developed to address this gap through a two-day, practice-oriented program integrating rhetorical training, evolutionary psychology, and structured peer feedback. We examined anonymized institutional evaluations from 450 medical students using descriptive statistics and combined inductive–deductive thematic and content coding to gauge the perceived educational utility of the course. The course received a mean satisfaction rating of 9.6/10, with approximately 74% of students assigning the maximum score. Inductive analysis identified interactivity (143 mentions), practical usefulness (76), feedback and improvement (75), positive atmosphere (51), instructor quality (47), and multimedia examples (37) as key strengths, while critiques primarily concerned breaks and scheduling (62), course length and intensity (59), and smaller concerns regarding feedback processes, content structure, and technical issues. Deductive coding indicated perceived improvements across five predefined dimensions: increased confidence, rhetorical fluency, feedback quality, peer recognition, and cultural inclusivity. Structured rhetorical training appears to be well received by learners and may provide a feasible model for embedding communication competence in medical education. These findings also offer a transferable template for integrating performance-based communication training into other programs. However, conclusions are limited by reliance on self-reported perceptions and the absence of a control group or direct assessment of applied communication outcomes. Full article

Background and Objectives: Inflammation contributes to plaque rupture and thrombosis in ST-elevation myocardial infarction (STEMI). The Aggregate Index of Systemic Inflammation (AISI) is a novel biomarker that reflects innate immune and thrombotic activation. Due to the connection between inflammation and thrombosis, higher AISI values could indicate a greater thrombus burden and the necessity of glycoprotein IIb/IIIa inhibitors. The aim of this study was to assess the relationship between AISI and tirofiban use during primary percutaneous coronary intervention (PCI) in STEMI patients. Materials and Methods: This retrospective study included 2624 STEMI patients who underwent primary PCI at a tertiary heart center between 2019 and 2024. Patients with pre-hospital fibrinolysis, missing laboratory data, or rescue PCI were excluded. AISI was calculated as (neutrophil × monocyte × platelet)/lymphocyte. The primary outcome was tirofiban use during PCI. Univariate and multivariable logistic regression analyses were performed to identify independent predictors, and receiver operating characteristic (ROC) curve analysis was used to evaluate AISI performance. Statistical significance was defined as p < 0.05. Results: Among the 2624 patients with STEMI undergoing primary PCI, tirofiban was administered in 23.5% of cases. Patients receiving tirofiban had significantly higher AISI values (p < 0.001). ROC analysis demonstrated that AISI predicted tirofiban use with a modest discriminative performance (AUC = 0.566; 95% CI 0.536–0.596; p < 0.001). In multivariable logistic regression, younger age (OR 0.98; p < 0.001), higher AISI (per 100-unit increase; OR 1.01; p = 0.037), and lower LVEF (OR 0.98; p < 0.001) independently predicted tirofiban use, whereas admission glucose showed only borderline significance (p = 0.089). Conclusions: Elevated AISI was independently associated with tirofiban use during primary PCI, indicating that systemic inflammatory status parallels intraprocedural decision-making in STEMI. Although its discriminative performance was modest, AISI reflects systemic inflammatory–thrombotic activation in this clinical setting. Full article

Environmental time series, such as near-surface air temperature, exhibit strong multi-scale structure and persistent autocorrelation. Accurate forecasting therefore requires careful consideration of both temporal scale separation and serial dependence. In this study, we evaluate a unified framework that integrates Kolmogorov–Zurbenko (KZ) filtering with two classes of models: (i) classical regression with Cochrane–Orcutt autocorrelation correction, and (ii) an autocorrelation-adjusted Long Short-Term Memory (LSTM) network that learns an embedded correlation coefficient ($\rho$). All models are assessed using standardized meteorological predictors of T2M under walk-forward validation. The LSTM trained on raw predictors shows moderate performance (RMSE = 0.73, $R^2=0.46$, DW = 0.79), which improves after KZ filtering (RMSE = 0.59, $R^2=0.63$, DW = 1.84). Classical regression applied to KZ-decomposed predictors and corrected using the Cochrane–Orcutt procedure achieves substantially higher accuracy (RMSE = 0.41, $R^2=0.89$, DW $\approx 2.0$), outperforming the LSTM in both predictive precision and residual behavior. Visual diagnostics further confirm tighter predicted–actual alignment and near-white residuals in the classical models, whereas the LSTM retains small systematic deviations even after filtering. Overall, the results demonstrate that addressing multi-scale structures and autocorrelation had a greater impact than increasing model complexity. Integrating spectral decomposition with autocorrelation correction thus produces more reliable, statistically valid forecasts, demonstrating that classical regression with KZ filtering can surpass LSTM models in both accuracy and interpretability. These findings emphasize the value of combining time series–aware pre-processing with both traditional and neural network approaches for environmental prediction. Full article

Background/Objectives: Hepatocellular carcinoma remains a major cause of death from cancer globally. While ¹⁸F-FDG PET/CT is commonly used for tumor imaging, its sensitivity is limited, especially due to high liver background uptake. Recently, ⁶⁸Ga-FAPI PET/CT, which targets fibroblast activation protein in tumor stroma, has emerged as a promising diagnostic tool. In this study, we aimed to assess the diagnostic performance of ⁶⁸Ga-FAPI-04 PET/CT in HCC patients with and without liver cirrhosis and to explore the relationship between PET metrics, tumor size, and PIVKA-II serum marker. Methods: In this prospective single-center study, 59 patients with confirmed HCC (37 with cirrhosis, 22 without) underwent ⁶⁸Ga-FAPI-04 PET/CT. The standard dose (1.5–2.0 MBq/kg) was administered intravenously, and imaging was carried out 60 min post-injection. Semi-quantitative parameters including SUVmax, SUVmean, and tumor-to-background ratio were calculated. Diagnostic performance was assessed using histopathology and multimodal imaging. Statistical analyses included the Mann–Whitney U test and Spearman correlation. Results: The overall sensitivity for HCC detection was 89.8%, with a specificity of 60% and accuracy of 87%. Sensitivity and specificity showed a tendency to be lower in cirrhotic compared with non-cirrhotic patients, with a notably higher background liver uptake in cirrhosis (SUVmax 3.60 vs. 1.3, p < 0.001), resulting in lower TBR values (3.7 vs. 7.0, p < 0.001). A strong correlation between SUVmax and tumor size was seen in non-cirrhotic HCC, while a moderate association between SUVmax and PIVKA-II levels was observed in cirrhotic patients. Conclusions:⁶⁸Ga-FAPI-04 PET/CT demonstrates high sensitivity for HCC detection and may serve as a complementary imaging modality, particularly when interpreted through conventional cross-sectional imaging. Image interpretation in cirrhotic livers may be challenging due to increased background uptake and reduced TBR. Associations between PET-derived parameters, tumor size, and serum PIVKA-II levels should be considered hypothesis-generating and require validation in larger, multicenter studies with clinical outcome data. Full article

Sustainability concerns over the management and handling of the growing volume of waste tires have necessitated the exploration of potential applications for the reuse and recycling of this resource, as they are categorized as hazardous wastes and are typically incinerated through thermal processing or dumped in landfills, resulting in significant environmental issues. The recycled steel and textile fibers from tires can be incorporated in concrete to assist in mitigating this impending environmental calamity, primarily by enhancing the efficacy of concrete. The present study aims to investigate the effect of using recycled tire steel fibers (RTSF) and recycled tire textile fibers (RTTF) in concrete, as economically viable and environmentally friendly alternatives to commercially available fibers. Although literature on the use of recycled fibers in concrete is available, the research is very limited in terms of their hybrid use and with minimal environmental analysis. Consequently, to address the gaps, this research concentrates on the use of RTSF and RTTF as a hybrid mix in concrete with life cycle assessment (LCA) to balance the mechanical performance and environmental sustainability. The experimental work is formulated to suggest an optimum dose of RTSF and RTTF, as a hybrid mix form, to be incorporated in concrete that imparts sufficient strength and workability. The fibers were integrated with dosages of 0.75%, 1%, and 1.25% for RTSF and 0.25%, 0.5%, and 0.75% for RTTF, respectively, by volume in non-hybrid form, while in hybrid form, they were reinforced as four different combinations (1%:0.5%, 0.75%, 0.75%, 0.5%, 0.5%:0.5%, and 0.75%:0.25%) by volume of RTSF and RTTF, respectively. Fresh and hardened properties of concrete were tested according to the ASTM standards. The results showed that concrete with hybrid fibers outperformed the concrete with normal individual fibers in both fresh and hardened states tests. The mechanical strength results showed that the synergistic use of RTSF and RTTF can enhance the strength, toughness, ductility, and crack resistance of the concrete. The hybrid mix H1 comprising 1% RTSF and 0.5% RTTF was ascertained as the optimal mix showing the highest mechanical performance with embodied CO₂ and energy values only slightly higher than the control mix, while offering the significant sustainability benefit of utilizing recycled fibers. Full article

Air pollution, particularly fine particulate matter (PM_2.5), poses significant public health and environmental risks. This study explores the effectiveness of spatiotemporal graph neural networks (ST-GNNs) in forecasting PM_2.5 concentrations by integrating remote-sensing hyperspectral indices with traditional meteorological and pollutant data. The model was evaluated using data from Switzerland and the Gauteng province in South Africa, with datasets spanning from January 2016 to December 2021. Key performance metrics, including root mean squared error (RMSE), mean absolute error (MAE), probability of detection (POD), critical success index (CSI), and false alarm rate (FAR), were employed to assess model accuracy. For Switzerland, the integration of spectral indices improved RMSE from 1.4660 to 1.4591, MAE from 1.1147 to 1.1053, CSI from 0.8345 to 0.8387, POD from 0.8961 to 0.8972, and reduced FAR from 0.0760 to 0.0719. In Gauteng, RMSE decreased from 6.3486 to 6.2319, MAE from 4.4891 to 4.4066, CSI from 0.9555 to 0.9560, and POD from 0.9699 to 0.9732, while FAR slightly increased from 0.0154 to 0.0181. Error analysis revealed that while the initial one-day ahead forecast without spectral indices had a marginally lower error, the dataset with spectral indices outperformed from the two-day ahead mark onwards. The error for Swiss monitoring stations stabilized over longer prediction lengths, indicating the robustness of the spectral indices for extended forecasts. The study faced limitations, including the exclusion of the Planetary Boundary Layer (PBL) height and K-index, lack of terrain data for South Africa, and significant missing data in remote sensing indices. Despite these challenges, the results demonstrate that ST-GNNs, enhanced with hyperspectral data, provide a more accurate and reliable tool for PM_2.5 forecasting. Future work will focus on expanding the dataset to include additional regions and further refining the model by incorporating additional environmental variables. This approach holds promise for improving air quality management and mitigating health risks associated with air pollution. Full article

Fragaria vesca L., a widely distributed model species, serves as a key resource for studying the evolution and genetics of the Fragaria genus. Research has shown that R2R3-MYB transcription factors are crucial for plant growth and development. However, their specific role in cold resistance in F. vesca is not well understood. In this study, we used the latest genome data for the strawberry (F. vesca v6.0). We performed a genome-wide identification of the R2R3-MYB gene family in F. vesca. We identified a total of 106 R2R3-FvMYBs. Based on their predicted functions in plants, we classified these genes into 25 distinct subfamilies. We then conducted a comprehensive bioinformatics analysis of this family. We performed a detailed examination of the R2R3-FvMYBs structures and physicochemical properties. This analysis provided five key parameters for each protein: molecular weight, the number of amino acids, theoretical isoelectric point, grand average of hydropathicity (GRAVY), and instability index. Gene duplication analysis suggested that segmental duplications were a primary driver of the proliferation of this gene family. Promoter cis-acting element prediction revealed that a large proportion of R2R3-FvMYBs possess elements predominantly associated with phytohormone responsiveness and biotic/abiotic stress responses. Quantitative real-time reverse transcription PCR (qRT-PCR) results confirmed that the expression levels of several R2R3-FvMYBs were upregulated under cold stress. Furthermore, compared to wild-type controls, the overexpression of FvMYB103 in Arabidopsis thaliana enhanced cold tolerance, accompanied by increases in the relevant physiological indices. Collectively, these findings support further investigation into R2R3-MYB gene family to directly assess their contribution to cold resistance. Full article

This study investigates the use of the fine fraction of Brazilian residual kaolin, a material with no pozzolanic activity according to the modified Chapelle test, as a partial cement replacement in rendering mortars. The kaolin was classified into three granulometric fractions (coarse: 150–300 µm, intermediate: 75–150 µm, and fine: <75 µm) and incorporated at two filler contents (10% and 20% by weight). Mineralogical and chemical analyses revealed that the fine fractions contained higher proportions of kaolinite and accessory oxides, while medium and coarse fractions were dominated by quartz. Intensity ratios from XRD confirmed greater structural disorder in the fine fraction, which was associated with higher water demand but also improved particle packing and pore refinement. Fresh state tests showed that mortars with fine kaolin maintained higher density and exhibited moderate increases in air content, whereas medium and coarse fractions promoted greater entrainment. In the hardened state, fine kaolin reduced water absorption by immersion and capillary rise, while medium and coarse fractions led to higher porosity. Mechanical tests confirmed these trends: although compressive and flexural strengths decreased with increasing substitution, mortars containing the fine kaolin fraction consistently exhibited more moderate strength losses than those with medium or coarse fractions, reflecting their enhanced packing efficiency and pore refinement. Tensile bond strength results further highlighted the positive contribution of the kaolin additions, as the mixtures with 10% coarse kaolin and 20% fine kaolin achieved adhesion values only about 7% and 4% lower, respectively, than the control mortar after 28 days. All mixtures surpassed the performance requirements of NBR 13281, demonstrating that the incorporation of residual kaolin—even at higher substitution levels—does not compromise adhesion and remains compatible with favorable cohesive failure modes in the mortar layer. Despite the lack of pozzolanic activity, residual kaolin was used due to its filler effect and capacity to enhance particle packing and pore refinement in rendering mortars. A life cycle assessment indicated that the partial substitution of cement with residual kaolin effectively reduces the environmental impacts of mortar production, particularly the global warming potential, when the residue is modeled as a by-product with a negligible environmental burden. This highlights the critical role of methodological choices in assessing the sustainability of industrial waste utilization. Full article

Background: Cigarette smoking remains one of the most important preventable causes of respiratory morbidity, exerting detrimental effects even in young adults. Medical students represent a particularly relevant population, as the lifestyle habits they adopt during their training years may influence both their personal health and professional credibility. Methods: We conducted a cross-sectional analysis of 264 medical students from the University of Medicine, Pharmacology, Science and Technology of Târgu-Mures, aged 18–30 years, stratified according to smoking status, type of tobacco product used, and lifestyle characteristics (athletic vs. sedentary). Standardized spirometry was performed to assess FVC, FEV₁, FEV₁/FVC ratio, PEF, and small airway flow parameters (MEF₂₅, MEF₅₀, MEF₇₅). Statistical comparisons between groups were performed using t-tests, Mann–Whitney U tests, chi-square tests, and correlation analyses, with p < 0.05 considered statistically significant. Results: Smokers demonstrated significantly lower values for FEV₁, PEF, and MEF parameters compared with non-smokers, confirming early functional impairment of both large and small airways. Within the smoking group, users of e-cigarettes or heated tobacco products exhibited more favorable FEV₁ and small airway flow values than conventional cigarette smokers. However, differences in FVC were less pronounced. Significantly, athletes consistently outperformed their sedentary peers across all respiratory parameters, regardless of smoking status, with markedly higher FEV₁, FVC, and MEF values and a lower prevalence of obstructive patterns. Cumulative smoking exposure (pack-years) was inversely associated with small airway function, whereas higher levels of physical activity were independently linked to a pronounced protective effect. Conclusions: Even in early adulthood, smoking is related to measurable declines in lung function, particularly affecting small airway dynamics. Although alternative products may appear less harmful than conventional cigarettes, they cannot be considered risk-free. Conversely, regular physical activity demonstrated a protective association in the case–control analysis, attenuating functional decline and supporting the preservation of long-term respiratory health. These findings underscore the importance of integrated prevention strategies in medical universities, combining smoking cessation initiatives with the systematic promotion of physical activity to safeguard the health of future physicians and reinforce their role as credible health advocates. Full article

Background: Serum C–C motif chemokine ligand 18 (seCCL18) in systemic sclerosis (SSc) has been primarily associated with progressive interstitial lung disease (SSc-ILD) and mortality. However, its relationship with non-pulmonary organ involvement, disease activity, and long-term outcome has not been comprehensively evaluated. We therefore examined the clinical relevance of seCCL18 in a single-center SSc cohort. Methods: A total of 151 patients with SSc (83 diffuse cutaneous (dcSSc), 68 limited cutaneous SSc (lcSSc); median (IQR) disease duration: 9 (4;16) years) and 47 age- and sex-matched healthy controls (HCs) were enrolled. Serum CCL18 concentrations were measured by enzyme-linked immunosorbent assay. Elevated seCCL18 was defined as >130 ng/mL (mean + 2 SD of the healthy control group). Organ involvement and disease activity (EUSTAR Activity Index, EUSTAR-AI) were assessed at baseline, while survival was analysed longitudinally. Results: Patients with SSc had significantly higher seCCL18 levels than HCs (mean ± SD: 99.9 ± 43.2 vs. 75.0 ± 27.5 ng/mL, p < 0.01). Elevated seCCL18 was associated with SSc-ILD (81.1% vs. 60.5%, p = 0.022), reduced forced vital capacity (FVC < 70%: 16.2% vs. 3.5%, p = 0.006), and reduced diffusing capacity for carbon monoxide (DLCO < 70%: 80.6% vs. 54.4%, p = 0.005). Higher seCCL18 levels were observed in patients with myocardial disease (104.8 ± 41.8 vs. 83.8 ± 44.2 ng/mL, p = 0.008), left ventricular diastolic dysfunction (107.1 ± 40.5 vs. 84.5 ± 45.0 ng/mL, p < 0.001), and oesophageal involvement (110.7 ± 38.3 vs. 93.3 ± 43.1 ng/mL, p = 0.009). SeCCL18 levels above the cut-off were more frequently associated with tendon friction rubs (51.4% vs. 27.4%, p = 0.007), active disease (EUSTAR-AI ≥ 2.5: 73% vs. 44%, p = 0.002), and elevated inflammatory markers (CRP > 5 mg/L: 51.4% vs. 19.3%, p < 0.001; ESR > 28 mm/h: 37.8% vs. 18.4%, p = 0.015). During a median follow-up of 87 months, 22 patients (15%) died. Elevated baseline seCCL18 predicted poorer survival in univariate analysis (log-rank p = 0.013) and remained an independent predictor of mortality in multivariable Cox regression (HR 1.789; 95% CI 1.133–2.824; p = 0.013), together with declining DLCO and reduced six-minute walk test performance. Conclusions: Elevated seCCL18 may identify patients with systemic sclerosis who exhibit a more severe multisystem phenotype, including cardiopulmonary, gastrointestinal, and musculoskeletal involvement, increased inflammatory activity, and reduced long-term survival. These findings suggest that seCCL18 may have some clinical utility as a prognostic biomarker reflecting widespread disease involvement beyond the lungs, even in patients with long-standing disease; however, the lack of an established cut-off value requires further validation in prospective, multicentre studies. Full article

Background/Objectives: Sarcopenia is an age-related decline in muscle mass and strength, reducing mobility and functional independence and increasing the risk of falls. Non-pharmacological interventions remain the most effective strategies to prevent or delay its progression, with exercise recognized as the primary approach. Virtual reality (VR)-based training has recently emerged as a promising tool to promote physical activity; however, its application among the oldest-old individuals remains underexplored. This is a randomized controlled pilot study to evaluate the effects of VR-based intervention using the game “Beat Saber” on muscle strength and selected physical performance indicators related to sarcopenia risk in older adults. Methods: Thirty-eight residents (mean age: 87.2) of a long-term care facility were randomly assigned to either a VR group or a control group. The VR group participated in 12 supervised VR-based training sessions of 20 min per session, three times per week for four weeks. Handgrip strength, the arm curl test, 30-s chair stand, a 2-min step-in-place test, and an 8-foot up-and-go test were assessed before and after the intervention. Results: Linear mixed-model analyses revealed significant group-by-time interactions for upper- and lower-limb strength (handgrip, arm curl, chair stand; p < 0.05), favoring the VR group. Agility and endurance (8-foot up-and-go, 2-min step-in-place) showed no significant interactions. In the VR group, the 30-s chair stand performance correlated positively with the arm curl and the 2-min step-in-place tests results, while handgrip strength correlated with the arm curl performance. In the control group, the 30-s chair stand test results correlated strongly with the 8-foot up-and-go and 2-min step-in-place tests, but no significant correlations were found for handgrip strength. Conclusions: The findings indicate short-term functional benefits of VR exercise among the oldest-old adults. VR-based training appears to be an effective and well-tolerated method to enhance physical performance in individuals aged 80 and older and may represent a valuable strategy for improving functional performance indicators associated with sarcopenia risk in adults aged 80 years and older. Full article

Introduction: The sustained global epidemic of Human Immunodeficiency Virus (HIV) necessitates comprehensive, region-specific surveillance to inform public health policy. This 30-year retrospective observational cohort study delineated the epidemiological patterns, transmission dynamics, treatment efficacy, and long-term clinical outcomes of HIV infection in Oman to strategically align preventative and therapeutic programs with Oman’s Vision 2040 framework. Methods: We analyzed the clinical and epidemiological data of 429 confirmed HIV-positive patients with a minimum follow-up period of six months, registered at a secondary care facility in North Batinah, Oman, between January 1995 and December 2024. Predictors of mortality were rigorously assessed utilizing Kaplan–Meier survival analysis and Cox proportional hazards regression models. Continuous variables were evaluated using independent sample t-tests or Mann–Whitney U tests, while categorical variables employed chi-square or Fisher’s exact tests. Results: The cohort exhibited a male predominance (70.6%) with a mean age at diagnosis of 32.8 years (SD ± 12.17). Heterosexual contact constituted the predominant mode of acquisition (56%), followed by bisexual (17%) and homosexual (12%) contacts. Although 67.1% of patients presented with early, asymptomatic disease (WHO Stage 1), opportunistic infections were evident in 28.1% of the cohort, with recurrent sepsis (8.4%) and bacterial pneumonia (3.5%) being the most frequent complications. The WHO clinical stage at presentation was confirmed as a highly significant predictor of survival (p < 0.0001). Stage 1 patients achieved excellent long-term prognosis (approximately 75% survival beyond 30 years), markedly contrasting with Stage 4 patients, whose survival declined sharply (median survival of approximately 8 years, and only 10–15% surviving past 20 years). The tenofovir/emtricitabine/efavirenz regimen showed superior efficacy, achieving 75% survival at 30 years, relative to zidovudine-based regimens, which showed significantly poorer performance (15–20% survival at 20 years). Conclusions: This investigation substantiates the shift toward predominant heterosexual transmission and emphasizes the critical prognostic significance of the clinical stage at diagnosis. Optimal long-term survival mandates prompt diagnosis, timely initiation of contemporary antiretroviral therapies, and sustained viral suppression. These findings offer crucial evidence to strengthen HIV prevention and treatment programs within Oman. Full article