Search Results (1,254)

Photocatalytic composite materials (TiO₂/SiO₂/BFSF) were first fabricated using the sol–gel method of loading SiO₂ and TiO₂ on blast furnace slag fibers (BFSFs) in sequence and using them as a new carrier. Then, TG-DTA, XRD, BET, SEM-EDS, and UV-Vis absorption spectra, as well as spectrophotometric measurements, were employed to analyze the physicochemical properties of TiO₂. The influence of SiO₂ coating, the number of impregnations in TiO₂ sol, the calcination temperature, and the number of repeated usages on the activity of TiO₂/SiO₂/BFSF was researched by analyzing the degradation of methylene blue (MB) aqueous solution. The results show that SiO₂ could increase the load of TiO₂, impede the growth of TiO₂ grains, and inhibit the recombination of electron–hole pairs, ultimately enhancing the photocatalytic activity of samples. The activity of TiO₂/SiO₂/BFSF first quickly increased and then slowly decreased with an increase in the loading times of TiO₂ sol and calcination temperature. After three impregnations in TiO₂ sol and calcining at 450 °C for 2.5 h, a uniform and compact anatase TiO₂ thin film was deposited on the surface of TiO₂/SiO₂/BFSF, showing the strongest activity. When this sample was used to degrade MB aqueous solution for 180 min under ultraviolet light irradiation, the degradation proportion reached a maximum of 96%. After four reuses, the degradation ratio could still reach 67%. In addition, three potential photocatalytic mechanisms were proposed. Finally, the high-value-added application of blast furnace slag for preparing photocatalytic composite materials was achieved, successfully turning solid waste into “treasure”. Full article

Piping systems can be analogized to the “vascular systems” of vessels, but their transmission characteristics often result in loud noises and large vibrations. The integration of flexible inserts within these piping systems has been shown to isolate and/or mitigate such vibrations and noise. In this work, a novel sandwich flexible insert (NSFI) was presented specifically to reduce the vibrations and noise associated with piping systems on vessels. In contrast to conventional flexible inserts, the NSFI features a distinctive three-layer configuration, comprising elastic inner and outer layers, along with a honeycomb core exhibiting a zero Poisson’s ratio. The dynamic characteristics, specifically axial impedance, of the fluid-filled NSFI are examined utilizing a fluid–structure interaction (FSI) four-equation model. The validity of the theoretical predictions is corroborated through finite element analysis, experimental results, and comparisons with existing literature. Furthermore, the study provides a comprehensive evaluation of the effects of geometric and structural parameters on the dynamic characteristics of the NSFI. It is worth noting that axial impedance is significantly affected by these parameters, which suggests that the dynamic characteristics of the NSFI can be customized by parameter adjustments. Full article

Polycystic ovary syndrome (PCOS) is a complex condition affecting women of reproductive age, characterized by menstrual irregularities, hyperandrogenism, polycystic ovarian morphology, and low-grade inflammation accompanied by oxidative stress and increased autoimmune risk, particularly Hashimoto’s thyroiditis. Many studies have examined thyroid autoantibodies—anti-thyroid peroxidase antibodies (anti-TPO) and anti-thyroglobulin antibodies (anti-TG)—in PCOS; however, observed differences in baseline thyroid-stimulating hormone (TSH) levels and body mass indices (BMIs) impede a direct interpretation of the results. This systematic review and meta-analysis aimed to summarize the available evidence on the prevalence and levels of anti-TPO and anti-TG in women with PCOS. We conducted a systematic search of PubMed, Scopus, and Embase, which yielded 40 eligible, observational studies including 6045 women with PCOS and 4527 controls. Subgroup analyses were conducted separately for TSH- and BMI-matched populations. Anti-TPO prevalence (odds ratio [OR] = 2.03; 95% confidence interval [CI]: 1.35–3.04; p = 0.0006) and levels (standardized mean difference [SMD] = 0.63; 95% CI: 0.37–0.88; p < 0.00001) were significantly higher in PCOS patients. Anti-TG prevalence (OR = 1.92; 95% CI: 1.23–3.01; p = 0.004) and levels (SMD = 0.41; 95% CI: 0.18–0.64; p = 0.0004) were also significantly elevated. In matched subgroups, prevalence differences were no longer significant, though anti-TPO levels remained significantly elevated and anti-TG levels were borderline significant in the TSH-matched subgroup of PCOS women. Although differences in thyroid autoantibody prevalence in women with PCOS appear to be driven by elevated TSH levels and BMIs, the persistently increased antibody levels in the majority of matched subgroups suggest that PCOS itself may contribute independently to heightened autoimmune activation. Full article

This study presents a compact and high-efficiency microstrip antenna integrated with a square electromagnetic band-gap (EBG) structure for radio frequency energy harvesting to power battery-less Internet of Things (IoT) sensors and medical devices in the 5.8 GHz Industrial, Scientific, and Medical (ISM) band. The proposed antenna features a compact design with reduced physical dimensions of 36 × 40 mm² (0.69λ_o × 0.76λ_o) while providing high-performance parameters such as a reflection coefficient of −27.9 dB, a voltage standing wave ratio (VSWR) of 1.08, a gain of 7.91 dBi, directivity of 8.1 dBi, a bandwidth of 188 MHz, and radiation efficiency of 95.5%. Incorporating EBG cells suppresses surface waves, enhances gain, and optimizes impedance matching through 50 Ω inset feeding. The simulated and measured results of the designed antenna show a high correlation. This study demonstrates a robust and promising solution for high-performance wireless systems requiring a compact size and energy-efficient operation. Full article

Background and Objectives: Malnutrition is one of the most common complications in patients undergoing hemodialysis (HD) and is closely linked to increased morbidity and mortality. This study aimed to investigate the nutritional status of HD patients and the clinical relevance of bioelectrical impedance analysis (BIA) parameters such as the percent body fat (PBF), skeletal muscle mass index (SMI), extracellular water-to-total body water ratio (ECW/TBW), and phase angle (PhA) in assessing malnutrition in Vietnamese HD patients. Materials and Methods: This cross-sectional study was conducted among 184 patients undergoing hemodialysis in Hanoi, Vietnam. The BIA parameters were measured by the InBody S10 body composition analyzer, while malnutrition was assessed by the geriatric nutritional risk index (GNRI), with a GNRI <92 classified as a high risk of malnutrition. The independent BIA variables for predicting malnutrition and its cut-off values were explored using logistic regression models and a receiver operating characteristic (ROC) curve analysis, respectively. Results: Among the study population, 42.9% (79/184) of patients were identified as being at a high risk of malnutrition. The multivariate logistic regression analysis revealed that a higher ECW/TBW was independently associated with an increased risk of malnutrition, while the PBF, SMI, and PhA expressed significant and inverse associations with the malnutrition risk after adjusting for multiple confounders. The cut-off values for predicting the high risk of malnutrition in overall HD patients were determined to be 20.45%, 7.75 kg/m², 5.45°, and 38.03% for the PBF, the SMI, the PhA, and the ECW/TBW ratio, respectively. Conclusions: BIA parameters, including the PBF, SMI, PhA, and ECW/TBW ratio, could serve as indicators of malnutrition in general Vietnamese patients with HD. Full article

The education sector in Tanzania faces significant challenges, especially in public primary schools. Unmanageably large classes and critical teacher–pupil ratios hinder the provision of tailored tutoring, impeding pupils’ educational growth. However, artificial intelligence (AI) could provide a way forward. Advances in generative AI can be leveraged to create interactive and effective intelligent tutoring systems, which have recently been built into embodied systems such as social robots. Motivated by the pivotal influence of teachers’ attitudes on the adoption of educational technologies, this study undertakes a qualitative investigation of Tanzanian primary school mathematics teachers’ perceptions of contextualised intelligent social robots. Thirteen teachers from six schools in both rural and urban settings observed pupils learning with a social robot. They reported their views during qualitative interviews. The results, analysed thematically, reveal a generally positive attitude towards using social robots in schools. While commended for their effective teaching and suitability for one-to-one tutoring, concerns were raised about incorrect and inconsistent feedback, language code-switching, response latency, and the lack of support infrastructure. We suggest actionable steps towards adopting tutoring systems and social robots in schools in Tanzania and similar low-resource countries, paving the way for their adoption to redress teachers’ workloads and improve educational outcomes. Full article

Background/Objectives: Since breast cancer (BC) survival rates have increased to 91% at 5 years and 80% at 15 years postdiagnosis, there is a growing awareness of the importance of addressing the long-term well-being of patients. Consequently, integrative oncology, which combines standard therapies with complementary approaches (nutrition, mind–body practices, and lifestyle modifications), has emerged as a patient-centred model aimed at improving symptom management, treatment adherence, and overall quality of life (QoL). This study aims to demonstrate how integrative therapies can benefit body composition, phase angle, and fluid and electrolyte balance through bioelectrical impedance analysis (BIA). Methods: This study considers a patient who underwent BC surgery and was enrolled in the AMICO clinic for anamnesis, as well as their oncological pathology data, assessment of QoL, and BIA. The breast surgeon specialising in integrative oncology therapies prescribed the patient curcumin and polydatin, moderate physical activity, a balanced diet, and Qigong sessions. The patient underwent monitoring through haematochemical analysis, BIA, and a QoL questionnaire, with follow-up every four months. Results: Between 4 and 12 months, fat mass (FM) and body mass index (BMI) markedly decreased, whereas fat-free mass (FFM), total body water (TBW), and skeletal muscle mass (SMM) increased progressively. Moreover, the improvements in the Na/K ratio and phase angle (PhA) suggest a shift toward better electrolyte and fluid balance and enhanced cellular integrity and membrane function. Equally outstanding were her psychological benefits in terms of mood, sleep, anxiety, and melancholy. Conclusions: Patient progress in body composition, metabolic function, pain management, and psychological status measured during the 12-month follow-up demonstrates the potential benefits of an integrative approach to supportive cancer care. Full article

Traditional intensive agricultural system impedes ecological functions, such as nutrient cycling and biodiversity conservation, resulting in excessive nitrogen discharge, CH₄ emission, and ecosystem service losses. To enhance critical ecosystem services and mitigate environmental externalities in paddy fields, we developed a multi-objective agricultural system (MIA system), which combines two eco-functional units: paddy wetlands and Beitang (irrigation water collection pond). Pilot study results demonstrated that the MIA system enhanced biodiversity and inhibited pest outbreak, with only a marginal reduction in rice production compared with the control. Additionally, the paddy wetland effectively removed nitrogen, with removal rates of total nitrogen and dissolved inorganic nitrogen ranging from 0.06 to 0.65 g N m⁻² d⁻¹ and from 0.02 to 0.22 g N m⁻² d⁻¹, respectively. Continuous water flow in the paddy wetland reduced the CH₄ emission by 84.4% compared with the static water conditions. Furthermore, a simulation experiment indicated that tide flow was more effective in mitigating CH₄ emission, with a 68.3% reduction compared with the drying–wetting cycle treatment. The emergy evaluation demonstrated that the MIA system outperformed the ordinary paddy field when considering both critical ecosystem services and environmental externalities. The MIA system exhibited higher emergy self-sufficiency ratio, emergy yield ratio, and emergy sustainable index, along with a lower environmental load ratio. Additionally, the system required minimal transformation, thus a modest investment. By presenting the case of the MIA system, we provide a theoretical foundation for comprehensive management and assessment of agricultural ecosystems, highlighting its significant potential for widespread application. Full article

The development of lightweight composites with superior mechanical properties and electromagnetic interference (EMI) shielding performance is essential for various structural and functional applications. This study investigates the effect of hybrid nanocarbon (graphene nanosheet (GNS) and carbon nanotube (CNT)) reinforcements on the properties of magnesium (Mg) matrix composites. Specifically, the GNS-CNT hybrid, which forms a three-dimensional interconnected network structure, was analyzed and compared to composites reinforced with only GNSs or CNTs. The objective was to determine the benefits of hybrid reinforcements on the mechanical strength and EMI shielding capability of the composites. The results indicated that the GNS-CNT/Mg composite, at a nanocarbon content of 0.5 wt.% and a GNS-CNT ratio of 1:2, achieved optimal performance, with a 55% increase in tensile strength and an EMI shielding effectiveness of 70 dB. The observed enhancements can be attributed to several key mechanisms: effective load transfer, which promotes tensile twinning, along with improved impedance matching and multiple internal reflections within the GNS-CNT network, which enhance absorption loss. These significant improvements position the composite as a promising candidate for advanced applications requiring high strength, toughness, and efficient electromagnetic shielding, providing valuable insights into the design of high-performance lightweight materials. Full article

Background: Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder characterized by reproductive and metabolic abnormality disorders. Dietary factors influence the body composition and hydration status, which may exacerbate PCOS symptoms. The aim of this study was to assess the associations between the habitual nutrient intake and bioelectrical impedance analysis parameters in Polish women with PCOS and healthy controls, in order to identify potential nutritional targets for a non-pharmacological intervention. Methods: This study involved 50 women aged 18–45 years (25 with PCOS and 25 healthy). Participants kept 7-day food diaries and their body composition was assessed using the SECA mBCA 515 analyzer. The nutrient intake was compared with EFSA recommendations. Results: Women with PCOS had a higher body weight, waist circumference and body mass index, visceral adipose tissue, and fat mass index, despite no difference in their total energy intake. They consumed more omega-3 fatty acids (EPA + DHA) than the control group. Vitamin D deficiency and irregular supplementation were common in both groups. Body composition parameters such as the phase angle and ECW/TBW ratio correlated with the diet quality—especially with protein; fiber; and vitamin B2, B12, and folate levels. Conclusions: The obtained results showed significant differences in body compositions and the presence of a relationship between the nutrient intake and bioimpedance parameters in women with PCOS. These results emphasize the importance of a comprehensive nutritional and body composition assessment in planning dietary interventions in this group of patients. Full article

Enhancing the resilience of renewable energy systems in ultra-weak grids is crucial for promoting sustainable energy adoption and ensuring a reliable power supply during disturbances. Ultra-weak grids characterized by a very low Short-Circuit Ratio, less than 2, and high grid impedance significantly impair voltage and frequency stability, imposing challenging conditions for Inverter-Based Resources. To address these challenges, this paper considers a 110 KVA, three-phase, two-level Voltage Source Converter, interfacing a 700 V DC link to a 415 V AC ultra-weak grid. X/R = 1 is controlled using Sinusoidal Pulse Width Modulation, where the Grid-Connected Converter operates in Grid-Forming Mode to maintain voltage and frequency stability under a steady state. During symmetrical and asymmetrical faults, the converter transitions to Grid-Following mode with current control to safely limit fault currents and protect the system integrity. After fault clearance, the system seamlessly reverts to Grid-Forming Mode to resume voltage regulation. This paper proposes an improved control strategy that integrates voltage feedforward reactive power support and virtual capacitor-based virtual inertia using Active Disturbance Rejection Control, a robust, model-independent controller, which rapidly rejects disturbances by regulating d and q-axes currents. To test the practicality of the proposed system, real-time implementation is carried out using the OPAL-RT OP4610 platform, and the results are experimentally validated. The results demonstrate improved fault current limitation and enhanced DC link voltage stability compared to a conventional PI controller, validating the system’s robust Fault Ride-Through performance under ultra-weak grid conditions. Full article

The quarter-wave transformer is a useful circuit for impedance matching. In this paper, we use three equal-length transmission lines to design dual-band quarter-wave transformers. Closed-form design equations are derived. The proposed structure is found to be suitable for dual-band operation with a frequency ratio greater than 5. Numerous microwave passive components are composed of quarter-wave transformers. For these components consisting of quarter-wave transformers, the use of dual-band quarter-wave transformers can inherently result in dual-band operation. The proposed structure is, therefore, a simple and effective element for designing dual-band microwave passive components with a frequency ratio greater than 5. Because the existing techniques for designing dual-band circuits are mostly suitable for frequency ratios lower than 5, the proposed structure, therefore, complements the existing techniques. To demonstrate the applicability of the structure, two directional couplers, namely, a dual-band branch-line hybrid and a dual-band rat-race hybrid, are designed and fabricated on a RO4003C substrate. Measurement results validate the applicability of the proposed structure. Full article

This paper presents a symmetry-driven broadband circularly polarized magnetoelectric dipole antenna with bandpass filtering response, where the principle of symmetry is strategically employed to enhance both radiation and filtering performance. The antenna’s circular polarization is achieved through a symmetrical arrangement of two orthogonally placed metallic ME dipoles combined with a phase delay line, creating balanced current distributions for optimal CP characteristics. The design further incorporates symmetrical parasitic elements—a pair of identical inverted L-shaped metallic structures placed perpendicular to the ground plane at −45° relative to the ME dipoles—which introduce an additional CP resonance through their mirror-symmetric configuration, thereby significantly broadening the axial ratio bandwidth. The filtering functionality is realized through a combination of symmetrical modifications: grid slots etched in the metallic ground plane and an open-circuited stub loaded on the microstrip feed line work in tandem to create two radiation nulls in the upper stopband, while the inherent symmetrical properties of the ME dipoles naturally produce a radiation null in the lower stopband. This comprehensive symmetry-based approach results in a well-balanced bandpass filtering response across a wide operating bandwidth. Experimental validation through prototype measurement confirms the effectiveness of the symmetric design with compact dimensions of 0.96${\lambda }_0$ × 0.55${\lambda }_0$ × 0.17${\lambda }_0$ (${\lambda }_0$ is the wavelength at the lowest operating frequency), demonstrating an impedance bandwidth of 66.4% (2.87–5.05 GHz), an AR bandwidth of 31.9% (3.32–4.58 GHz), an average passband gain of 5.5 dBi, and out-of-band suppression levels of 11.5 dB and 26.8 dB at the lower and upper stopbands, respectively, along with good filtering performance characterized by a gain-suppression index (GSI) of 0.93 and radiation skirt index (RSI) of 0.58. The proposed antenna is suitable for satellite communication terminals requiring wide AR bandwidth and strong interference rejection in L/S-bands. Full article

Background/Objectives: Celiac disease (CD) alters nutrient absorption and body composition, especially during childhood. Although adherence to a gluten-free diet (GFD) promotes mucosal recovery, its impact on cellular functionality and metabolic balance remains underexplored. This study aims to evaluate the utility of bioelectrical impedance vector analysis (BIVA) in assessing nutritional status, inflammatory improvement, and body composition changes in pediatric patients with CD following a GFD. Methods: Seventy-nine children aged 5–14 years were studied. Three groups were analyzed: (1) 25 children with newly diagnosed CD, evaluated at diagnosis and after 12 months of GFD (prospective cohort); (2) 25 CD patients on a GFD for over 24 months (cross-sectional); and (3) 29 healthy controls. Body composition (fat mass (FM), fat-free mass (FFM), body cell mass (BCM), phase angle (PhA), and Na⁺/K⁺ ratio) was measured. GFD adherence was assessed and a dietary assessment was also performed. Results: After 12 months on a GFD, newly diagnosed CD patients showed significant increases in FM (from 8.2 to 10.1 kg, p = 0.001), FFM (p = 0.001), and BCM (p = 0.0001), along with a significant decrease in the Na⁺/K⁺ ratio (p = 0.015). Compared to healthy controls, CD children on GFD for more than 24 months had higher FM (12.2 vs. 8.8 kg, p = 0.013) and lower Na⁺/K⁺ ratios (p = 0.006). PhA increased slightly over time but did not reach statistical significance. Conclusions: Our study suggests that the adherence to a GFD leads to improved body composition and cellular homeostasis in children with CD, as reflected by increases in BCM and reductions in Na⁺/K⁺ ratio, making it a promising biomarker for monitoring inflammation and cellular recovery. Full article

With the increasing penetration of distributed generation and the diversification of electrical equipment, distribution networks face issues like three-phase unbalance and harmonic currents, while the voltage stability and inertia of the grid-connected system also decrease. A certain amount of energy storage is needed in a Distribution Static Synchronous Compensator (DSTATCOM) to manage power quality and actively support voltage and inertia in the network. This paper first addresses the limitations of traditional $dq0$ compensation algorithms in effectively filtering out negative-sequence twice-frequency components. An improved $dq0$ compensation algorithm is proposed to reduce errors in detecting positive-sequence fundamental current under unbalanced three-phase conditions. Second, considering the impedance ratio characteristics of the distribution network, while reactive power voltage regulation is common, active power regulation is more effective in high-resistance distribution networks. A grid-forming model-based active and reactive power coordinated voltage regulation method is proposed. This method uses synchronous control to establish a virtual three-phase voltage internal electromotive force, forming a comprehensive compensation strategy that combines power quality improvement and active voltage support, exploring the potential of energy storage DSTATCOM applications in distribution networks. Finally, simulation and experimental results demonstrate the effectiveness of the proposed control method. Full article