Sci

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.

The present paper concerns a new formulation of the optimal design problem of I-shaped multistep steel beam elements, based on the study of the plastic strain spread occurring in the relevant elements, with the aim of determining the length involved by the plastic deformation related to assigned load conditions and different constrained beam schemes. Material behavior is assumed as elastic–perfectly plastic, and the hypothesis of plane cross-sections is accepted. The functions defining the plastic strain spread are analytically obtained in the framework of Euler–Bernoulli beam theory. The proposed optimal design problem is a minimum volume one and the new constraint imposed on the length of the plasticized portion ensures that the minimum volume beam element also represents a maximum plastic dissipation one. Furthermore, the solution to the optimal design problem guarantees that the obtained multistep beam element ensures protection against brittle failure of the beam end sections, provides optimal cross-sections of the different portions belonging to Class 1 and ensures a suitable minimum value of the elastic flexural stiffness to respect the constraint on the deflection. Explicit reference is made to the so-called Reduced Beam Section (RBS), which characterizes the described multistep beam elements. Actually, the proposed formulation represents an innovative approach to obtaining an optimal beam element that really satisfies all the resistance, stiffness and ductility behavioral requirements. Some numerical applications conclude the paper, and their results are confirmed by appropriate FEM analyses in ABAQUS environment.

Assisted Reproductive Technology Units (ARTUs) constitute a rapidly growing sector in healthcare, where service quality and patient safety are closely intertwined with ethical principles, technological precision, and managerial efficiency. This study aims to explore quality management practices and certification standards—such as ISO 9001, ISO 15189, and ISO 13485—within ARTUs, with the goal of developing a model that enhances patient-centered outcomes. The analysis focuses on the roles of leadership, staff training, and internal auditing mechanisms as key factors for the successful implementation of quality management systems (QMSs). Through a structured literature review and thematic synthesis, this study identifies challenges that ARTUs face in aligning with international standards and highlights strategies that strengthen patient trust, transparency, and continuous improvement. The proposed model connects measurable quality indicators with patient perceptions and experiences, providing a comprehensive framework for sustainable quality development. This article contributes to the academic discourse on healthcare quality governance and offers practical insights for policymakers and administrators seeking to improve patient experience and organizational resilience in reproductive medicine.