Search Results (194)

The use of confuser–diffuser nozzles in power machines enables efficient conversion of gas energy into mechanical work. However, traditional Laval, Venturi, and Vitoszynski nozzles are associated with shock wave formation, causing energy losses, noise, and structural loading. This study proposes innovative jet nozzles with an internal streamlined body that forms annular flow rather than a classical diffusor. A rational computational design methodology based on the Venturi effect criterion and equality of cross-sectional area variation laws was developed. A couple of configurations with spindle-toroidal and ellipsoidal streamlined bodies were generated analytically, studied numerically, and confirmed experimentally. Based on the SST turbulence model, CFD simulations for a compressible flow (air) show that the proposed designs reduce the pressure jump from 60 kPa (traditional nozzle) to 20 kPa for the spindle-toroidal configuration and eliminate it for the ellipsoidal configuration. The Reynolds number in the throat decreases by a factor of 2.6, reducing turbulence. The outlet velocity increases by 3.0% for the spindle-toroidal design, while the ellipsoidal nozzle provides expansion with slightly lower velocity but a smoother velocity profile. Experimental thrust measurements agree with simulations within 2.6–6.7%. The proposed designs enhance energy efficiency, reduce erosion and vibration, and enable adaptive flow control via axial displacement of the streamlined body. Full article

Background: Antimicrobial resistance continues to threaten effective infection management worldwide and is driven largely by inappropriate prescribing practices. In Saudi Arabia, the cities of Makkah and Al-Madinah experience intense seasonal healthcare demand due to the annual pilgrimage, creating additional challenges for rational antibiotic use. This study aimed to evaluate physicians’ knowledge, attitudes, and prescribing behaviors related to antibiotics in these high-demand settings. Methods: A cross-sectional analytic study was conducted between June and August 2024 among physicians practicing in Makkah and Al-Madinah, including those participating in Hajj services. A previously validated, structured electronic questionnaire assessed knowledge of common pathogens, perceptions of antimicrobial resistance, prescribing influences, and counseling practices. The survey was distributed electronically to eligible physicians. Descriptive statistics were generated, and associations were examined using appropriate inferential tests with a 95% confidence level. Results: A total of 487 physicians participated. Most respondents (74%) correctly identified major bacterial causes of upper respiratory tract infections, and 90% acknowledged the association between prior antibiotic exposure and resistance. Nonetheless, misconceptions persisted regarding the benefit of antibiotics in viral conditions. Workload and patient expectations influenced prescribing behavior; 77% reported a greater likelihood of prescribing antibiotics during periods of high clinical pressure. While adherence to guideline-based practice was generally reported, variability existed in counseling practices and perceptions of stewardship policies. Conclusions: Although baseline knowledge was satisfactory, contextual and behavioral factors continue to influence prescribing decisions and may contribute to unnecessary antibiotic exposure, highlighting the need for strengthened antimicrobial stewardship strategies in high-demand healthcare environments. Full article

Over the past decades, gut microbiota has emerged as a critical modulator of human health and disease. Pregnancy involves substantial microbiota remodelling that influences offspring development, yet mechanisms linking maternal microbiota changes to gestational diabetes mellitus (GDM) remain unclear. The current literature lacks a comprehensive synthesis of pregnancy microbiota dynamics across healthy gestation to GDM, comparative human–murine analysis, and pregnancy-specific mechanistic frameworks distinct from type 2 diabetes models. This narrative review comprehensively synthesised evidence on gut microbiota composition in healthy pregnancy and GDM (2005–2025, NCBI PubMed) to identify convergent signatures and articulate pregnancy-specific mechanisms. Early pregnancy microbiota resembles non-pregnant individuals, whereas late pregnancy exhibits increased lactic acid-producing bacteria and reduced Firmicutes-to-Bacteroidetes (F/B) ratios. GDM exhibits pathological dysbiosis with elevated F/B ratios and reduced Bifidobacterium. Critically, GDM butyrate-producer patterns diverge from type 2 diabetes, suggesting pregnancy-specific mechanisms beyond glucose homeostasis. Despite these insights, methodological heterogeneity and cross-sectional designs constrain definitive conclusions. Longitudinal studies with standardised sequencing are essential to confirm consistent signatures and enable rational design of microbiota-modulating interventions (prebiotics, probiotics, synbiotics, postbiotics, diet) to optimise maternal health, prevent GDM, and support offspring development. Full article

Background: Fixed-dose combination drugs (FDCs) are combinations of two or more active ingredients in a single dosage form. These formulations have proven effective in combating the development of resistance in diseases such as tuberculosis and malaria. Despite the benefits observed in the aforementioned cases, fixed-dose antibiotics combinations (FDACs) are increasingly raising questions about their rationality. This is the case for several FDACs listed in the AWaRe classification as not recommended, which unfortunately remain available on the pharmaceutical market, particularly in low- and middle-income countries like the Democratic Republic of Congo (DRC). Objectives: To identify the essential medicines available in pharmacies open to the public in the city of Kinshasa and to assess their inclusion in the DRC’s National List of Essential Medicines (NLEM) and in the World Health Organization’s (WHO) List of Essential Medicines (LEM). The rationality of the FDACs circulating in the city of Kinshasa were also evaluated based on the 2023 AWaRe classification. Methods: A cross-sectional and descriptive study was conducted between February and October 2025 in Kinshasa. For this purpose, fifty registered pharmacies open to the public were selected by systematic random sampling as the research sample. Data collection consisted of completing a data collection form after we had provided the pharmacies’ owners with the necessary explanations regarding the importance of the study and guaranteed their anonymity. Results: The controlled FDACs encountered comprised 27 specialties across 15 different formulations. Out of 15 formulations, 12 (80%) were included on the WHO list of non-recommended antibiotics and were not included in the DRC’s NLEM nor in the WHO’s LEM. Some had been withdrawn from the market in their countries of manufacture. Of the 15 FDACs evaluated for their rationality and compliance, the injectable FDACs presented problems related to the relevance and completeness of information contained on their packaging. On their primary packaging, there was a significant difference in the expiration dates of the powder and sterile water for injection contained in the combination pack, ranging from 6 to 36 months. Furthermore, the secondary packaging lacked data related to the sterile water for injection contained in the combination pack. In addition, several medications contained the same therapeutic combination. For injectable FDAC, for example, the combination Ceftriaxone-Sulbactam was represented by eight medications. For oral FDACs, the combination Sulfamethoxazole-Trimethoprim was represented by seven medications. Globally, 100% of these drug combinations originated from India. Conclusions: Fifteen varieties of FDACs were available in Kinshasa, most of which (80%) were unsuitable. It is important that public health authorities address this situation and develop stricter guidelines for granting marketing authorizations, particularly for FDACs. Full article

Based on temperature–stress coupling simulation, a thermal source model for nanosecond pulsed hollow cathode electron beam surface modification is proposed. Dynamic thermal-stress changes from beam–surface interaction and their influence on micro–nano characteristics were systematically investigated. By analyzing maximum temperature/stress dynamics, cross-sectional remelted layer variations, and heating/cooling rates, the temperature and stress distribution in the micron-scale surface layer was comprehensively revealed, validating the model’s rationality. Combined with low, medium, and high pulse count experiments, the effects of thermal and stress factors on surface morphology and grain refinement were studied, elucidating underlying mechanisms through numerical correspondence. Results show irradiation effects confined to a 1.5–2 mm localized region, with extreme temperature changes (~10³ K) and stress variations (10³–10⁴ MPa) within tens of nanoseconds. Heating rates reached 10¹¹ K/s, cooling rates 10⁹–10¹⁰ K/s, exceeding microsecond pulsed beams by one to two orders. Simulated remelting zone diameter and thickness agreed well with experiments, confirming model validity. Grain refinement is primarily driven by rapid temperature distribution, generating instant solidification nucleation sites, with a secondary contribution from high-stress-induced plastic deformation forming sub-grains. Full article

This study presents the development of a three-dimensional (3D) filament assembly model for predicting the air permeability of woven fabrics composed of spun yarns. To address the limitations of conventional single-line yarn models, the proposed framework incorporates fiber-level geometric representations using non-uniform rational B-splines (NURBS) and simulates multiple weave patterns—including plain, basket, twill, and rib—under various set density configurations. Each yarn was modeled with accurate filament distribution and cross-sectional layering, enabling the construction of realistic unit-cell-based CAD geometries. Computational fluid dynamics (CFD) simulations were performed using the k-ε turbulence model in SolidWorks Flow Simulation and validated against experimental measurements conducted under ISO 9237:1995 conditions. The filament assembly model achieved high predictive accuracy, exhibiting a lower of percentage prediction errors than the single-line yarn path model, thereby more effectively capturing airflow behavior through inter-yarn and intra-yarn pores. These findings highlight the capability of integrated CAD/CFD methodologies for virtual prototyping of breathable textiles and provide a robust foundation for high-precision performance prediction in functional and technical fabric design. Full article

Background: Vaginal infections often present with overlapping symptoms and involve single or multiple pathogens. However, the relationship between clinical symptoms and molecularly defined vaginal pathogen profiles, especially in multi-pathogen infections, remains poorly characterized in a routine care setting. This study exams the connection between vaginal symptoms and pathogen profiles among women with vaginitis in Northern Vietnam. Methods: We conducted a multicenter cross-sectional study of women with vaginitis at Bac Ninh CDC and Hanoi Obstetrics and Gynecology Hospital between December 2023 and December 2024. Baseline demographics and clinical symptoms were assessed by physicians. Vaginal swabs were collected for pH measurement and pathogen detection using multiplex real-time PCR. The correlation was analyzed using logistic regression in GraphPad Prism v10.1.1. Results: Among 289 symptomatic women, abnormal vaginal discharge and itching were the most common symptoms. Gardnerella vaginalis was the most commonly detected pathogen, occurring alone or in combination with Candida albicans, Mycoplasma hominis, and other genital pathogens. Multi-pathogen infection was associated with abnormal vaginal discharge (OR = 5.44), itching (OR = 2.13), and elevated vaginal pH (OR = 4.70). Women at the tertiary hospital showed greater symptom burden (OR = 1.75) and higher prevalence of multi-pathogen infections (OR = 9.75) than those attending the provincial CDC. Conclusions: Multiplex real-time PCR combined with simple clinical indicators (symptom clustering and vaginal pH) provides practical diagnostic value for identifying multi-pathogen infections in symptomatic women. This integrated approach may support more accurate etiologic diagnosis and guide rational testing strategies, particularly in resource-limited settings. Full article

This study demonstrates that compressive strength in cement-stabilized rammed earth is governed by conditional, threshold-controlled interactions rather than by intrinsic mineralogical effects. A B + K (beidellite + kaolinite) content exceeding 15% defines a low-strength regime (median ≈ 44.6 kN), whereas B + K ≤ 5% allows medians above 90 kN under 7% forming moisture. Quartz-rich fractions show a global correlation of r = 0.71. The Kruskal–Wallis test confirms strong clay grouping influence (H = 72.78, p < 0.001). Analysis of the experimental dataset shows that most strength distributions deviate from normality, invalidating pooled parametric inference and justifying the use of distribution-free methods. At the global level, bulk density and quartz-rich fractions are the dominant positive contributors to strength. Meanwhile, forming moisture and high combined beidellite–kaolinite content (>15%) exerts a negative influence under elevated forming moisture (8%), whereas the effect of 1:1 and 2:1 clay minerals differs depending on their hydro-affinity and moisture regime. However, subgroup analyses reveal frequent reversals in both magnitude and sign of correlations, proving that mineral effects depend critically on cement dosage and moisture regime, revealing discrete strength regimes defined by hierarchical interactions between moisture, cement content, and mineralogical thresholds. The combined beidellite–kaolinite content was classified into ≤5%, 5–15%, and >15% groups. Specimens with B + K > 15% consistently formed a low-strength regime, with a median destructive load of approximately 44.6 kN (≈1.1–1.3 MPa depending on cross-sectional area). In contrast, mixtures with B + K ≤ 5% achieved median loads above 90 kN (≈2.5–3.0 MPa). Quartz-rich fractions showed a strong global positive correlation with strength (r = 0.71), while the grouped clay fraction exhibited a highly significant effect (Kruskal–Wallis H = 72.78, p < 0.001). A regime shift was observed between 7% and 8% forming moisture, where quartz correlation changed from strongly positive (r ≈ 0.70) to negative (r ≈ −0.69). Increasing cement content from 6% to 9% significantly improved strength (H = 12.30, p = 0.0005), although this effect diminished when B + K exceeded 15% or forming moisture reached 8%. Association rules further confirm that high or low strength emerges only from specific multivariate combinations. The results show that mineralogy influences CSRE strength primarily through interaction with technological parameters, providing a robust basis for regime-based interpretation and rational mixture design. Full article

This study investigates the factors associated with niyyah (worshipful intention) of Islamic bankers toward issuing green sukuk (G-sukuk) investment instruments. In particular, it analyses how bankers’ empathy, moral and ethical responsibilities, and self-efficacy are related with environmental awareness, perceived social support, and green tech innovation, respectively. These factors then predicted bankers’ niyyah toward issuing G-sukuk. The present research employed the theory of bounded rational planned behavior as its theoretical foundation. Data were collected from 390 bankers employed in different Islamic banks. Random sampling technique was employed for this cross-sectional study and for analyzing data, this study applied structural equation modeling. Findings indicate that all predictors are statistically significant and positively associated with bankers’ niyyah toward G-sukuk for ensuring sustainable finance. Furthermore, G-sukuk initiatives can help to lower the carbon emissions and other harmful substances, which would improve overall environmental sustainability and ecological contexts related to SDG-13. There is limited empirical evidence available on the G-sukuk perspective in Bangladesh. This study will provide practical insights for the bankers and policymakers. Full article

Recently, due to the expansion of telecommunication and power networks, as well as other structures, the demand for designing efficient and durable tall supporting columns has increased. Efficient steel columns are well known, including prestressed stayed beam–column systems. However, because of their relatively high cost, designers often turn to reinforced concrete structures, which are not only relatively cheaper but also sufficiently strong and resistant to aggressive external influences. Nevertheless, the large self-weight of reinforced concrete structures and considerable material consumption encourage the search for new efficient solutions. One such solution is the use of spun reinforced concrete structures. Compared to conventional reinforced concrete structures, these solutions not only reduce material consumption but also increase durability. This study examines an innovative prestressed stayed beam–column structure consisting of a spun reinforced concrete core and supporting prestressed steel tension ties. The behavior of such a composite structure is analyzed, and calculations of internal forces and displacements are presented. The rational parameters of the composing elements of this new prestressed stayed beam–column structure are discussed, and their influence on the stress–strain state of the structure is evaluated. Expressions are provided for calculating the rational bending moments of the spun reinforced concrete core. The obtained solutions make it possible to select rational cross-sections of the core and ties, as well as the required prestressing of the tension ties, without iterative calculations. Full article

Hydrodynamic models of river networks are commonly used for flood disaster simulation, and the accuracy of model parameter settings directly affects the reliability of simulation results. Among these, Manning’s roughness coefficient is the core parameter for calibrating one-dimensional(1D) hydrodynamic models, as it is the most sensitive and frequently adjusted parameter. Taking the Yunxi Area of Huai’an City as a case study, this paper proposes an integrated workflow using orthogonal experiments and successive approximation for calibrating Manning’s roughness coefficients in river networks. In this workflow, 13 river reaches (from six major rivers) serve as experimental factors. The Manning’s roughness coefficients for the main channel and floodplains are assigned different values as experimental levels. Model performance is evaluated using the Nash–Sutcliffe Efficiency (NSE) and Root Mean Square Error (RMSE). A multi-factor and multi-level orthogonal table L₂₇(3¹³) of main channel or floodplains roughness is alternately selected to design 27 sets of experiments. Through HEC-RAS simulation and orthogonal analysis, the roughness coefficients of the main channel and floodplains are alternately screened and successively approximated to the target values. Finally, the roughness coefficients of the main channel and floodplains for each river reach meeting the accuracy requirements are obtained, with corresponding values of NSE = 0.93 and RMSE = 0.04 m. The results show that orthogonal experimental design significantly reduces the number of simulation tests and effectively saves computational time and costs, while the successive approximation strategy addresses the complexity of solving problems with multiple decision variables. Additionally, the experimental factors consider variations in cross-section types and hydraulic conditions along the river by setting roughness coefficients in segments. The orthogonal experimental design ensures the relevance, simultaneity, and systematic nature of parameter adjustments across all river reaches, significantly enhancing the rationality and reliability of the model parameter calibration. Full article

Infertility affects 10–30% of couples globally, with significant psychological and social impacts in sub-Saharan Africa, where fertility is closely tied to identity and social status. To explore how couples’ understanding of infertility causes influences their treatment-seeking behaviours and healthcare decision-making processes in Ghana, this cross-sectional qualitative study used in-depth interviews with 24 married participants (nine dyads and six individuals) experiencing current or past infertility in Greater Accra, Ghana, from August to October 2023. Data were analysed using thematic analysis with NVivo version 15. Couples demonstrated comprehensive knowledge of infertility causes spanning medical, spiritual, cultural, and lifestyle factors, although they lacked knowledge of clinical diagnostic criteria. Three main treatment pathways emerged: medical/orthodox, herbal, and spiritual interventions, pursued either sequentially or concurrently. Decision-making was influenced by internal factors (treatment effectiveness, financial constraints, and safety concerns) and external factors (family influence and peer testimonials). Four distinct navigation strategies were identified: informed notification, trial periods and evaluation, parallel relationship management, and strategic sequencing. Couples experiencing infertility are sophisticated healthcare consumers who skilfully navigate pluralistic healthcare systems through strategic decision-making. Rather than representing non-compliance, their multimodal approaches reflect rational responses to structural constraints and cultural values. Healthcare systems should recognise and accommodate these navigation strategies to improve therapeutic relationships and outcomes. Full article

Background/Objectives: The COVID-19 pandemic exposed global weaknesses in healthcare preparedness and highlighted the pivotal role of the World Health Organization (WHO) in coordinating responses and issuing technical guidance. Among these, the document “Rational use of personal protective equipment (PPE) for COVID-19 and considerations during severe shortages” (December 2020) aimed to standardize PPE use amid global scarcity. This study assessed the awareness, implementation, and perceived usefulness of this WHO guidance among Polish healthcare personnel and evaluated discrepancies between the WHO expectations and workplace realities. Methods: A cross-sectional, anonymous online survey was conducted between July and September 2025 among employees of 243 randomly selected healthcare facilities in Poland (constituting 20% of all hospitals). The original 24-item questionnaire covered the demographics, awareness and implementation of the WHO PPE guidelines, and perceptions of their effectiveness during and after the pandemic. Data were analyzed descriptively. Results: A total of 542 healthcare workers participated, predominantly nurses (56.8%) and physicians (12.2%), with 86.8% being female and 59.3% having over 20 years of experience. Most respondents (76.5%) reported familiarity with the WHO PPE document, and 63.1% confirmed its implementation in their institutions. Over two-thirds (68.0%) reported that the guidelines improved their sense of safety at work. The main barriers to implementation included staff shortages (52.9%) and insufficient local guidance (20.6%). In 2025, 52.3% continue to apply the WHO recommendations, and 70.8% believe they remain relevant in current practice. However, 80.2% indicated that the WHO guidance should be more closely adapted to local conditions. Conclusions: The WHO PPE guidance was widely recognized and reported as implemented by respondents from participating healthcare facilities, contributing to improved preparedness. Nonetheless, limited institutional support and inadequate local adaptation reduced implementation effectiveness. Future WHO recommendations should better align with national healthcare contexts to enhance preparedness for future crises. Full article

Background/Objectives: Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for pain management but pose gastrointestinal (GI) and cardiovascular (CV) risks, particularly during long-term use. This study evaluated NSAID-prescribing patterns and the appropriateness of gastroprotective co-therapy among patients with varying GI and CV risk profiles. Methods: An observational, cross-sectional study was conducted in the outpatient pharmacy department over six months (March 2023 to August 2023) at a public secondary care facility. Data pertaining to patient demographics, NSAIDs prescription, and GI/CV risks were collected and reviewed from electronic health records. Descriptive statistics, chi-square tests, and logistic regression were performed. Results: A total of 1005 prescriptions containing 2051 NSAIDs were analyzed. Selective COX-2 inhibitors and non-selective NSAIDs were the most frequently prescribed. Only 42.1% of patients received proton-pump inhibitors despite guideline recommendations. Non-selective NSAIDs were significantly associated with CV history and GI risk (p < 0.0001). Logistic regression showed age, gender, CV history, and GI risk significantly influenced NSAID selection. Notably, non-selective NSAIDs continued to be prescribed among moderate- and high-GI-risk patients. Conclusions: Suboptimal adherence to guideline-recommended gastroprotective strategies was evident, particularly among high-risk patients. Comprehensive GI and CV risk assessment and the rational use of gastroprotective co-therapy are essential. Integrating evidence-based digital tools may enhance safer NSAID prescribing in routine practice. Full article

Background/Objectives: Weight loss supplements (WLS) are popular dietary agents; however, their effectiveness is rarely supported by scientific-based evidence. This cross-sectional study aimed to identify the types of WLS used among adult Poles in relation to sociodemographic factors, anthropometric indices, and physical activity (PA). Methods: The study was conducted among 1071 adults aged 19–80 years in Świętochłowice, a region in Poland with a high rate of overweightness and obesity. Body mass index (BMI), waist-to-hips ratio, and weight-to-height ratio were calculated. Fat mass percentage was assessed. Data on PA level and the use of WLS were collected via a face-to-face questionnaire. Results: Nearly 70% respondents declared consumption of WLS, including 486 females and 259 males. Among WLS consumers, 43.4% had normal BMI, and 6.3% were underweight. The most popular WLS were supplements aiming at enhancing thermogenesis (38.0% of WLS consumers), followed by WLS decreasing appetite (15.0%) and blocking dietary fat absorption (13.0%). Sociodemographic factors (sex, age, marital status, education and financial status) were strong determinants of using particular types of WLS. Mean values of anthropometric indices and PA level were different among consumers of various WLS. Conclusions: WLS use was common, including among individuals without overweightness/obesity, or cardiometabolic risk. Extensive educational programs and legislation are essential to promote justified, rational, effective, and safe methods for reducing excessive body mass. Full article