Search Results (1,879)

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by impaired glucose homeostasis, insulin resistance, and progressive β-cell dysfunction. Increasing evidence suggests that glucose homeostasis is regulated not only by peripheral metabolic organs but also by central nervous system and autonomic pathways. Photobiomodulation (PBM) has been reported to modulate mitochondrial function, oxidative stress, vascular responses, and neural activity; however, its potential influence on glycemic outcomes remains largely unexplored. Objective: This prospective pilot study aimed to evaluate the feasibility of applying multi-wavelength LED irradiation to a predefined cranial region and to explore preliminary glycemic outcomes in individuals with T2DM. Methods: Seven participants with physician-diagnosed T2DM receiving stable antidiabetic medication regimens were enrolled. Multi-wavelength LED irradiation (660, 850, and 940 nm) was applied bilaterally to the predefined S3 region of the skull. Irradiation parameters included an irradiance of 5 mW/cm² (0.005 W/cm²), an energy density of 4.5 J/cm², and an exposure duration of 900 s per session. Treatments were administered three times weekly for four weeks (12 sessions). Primary outcome measures included fasting blood glucose (Glucose AC) and glycated hemoglobin (HbA1c). Secondary outcomes included mean blood glucose, fasting insulin, C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR), lipid profile, and C-reactive protein (CRP). Exploratory paired statistical analyses were performed following assessment of data normality using the Shapiro–Wilk test. Results: Following the four-week intervention, fasting blood glucose and mean blood glucose were significantly reduced (p = 0.026 and p = 0.044, respectively), whereas HbA1c demonstrated a borderline reduction (p = 0.051). Changes in fasting insulin, C-peptide, HOMA-IR, lipid profile, and CRP were variable and did not reach statistical significance. No intervention-related adverse events were observed, and all participants completed the study protocol. Conclusions: Multi-wavelength LED irradiation applied to the predefined S3 region of the skull was feasible, safe, and well tolerated in individuals with T2DM. The observed preliminary glycemic outcomes support the feasibility of further investigation in larger randomized controlled trials. However, because of the small sample size, absence of a control group, and exploratory study design, the present findings should be interpreted cautiously and should not be considered evidence of clinical efficacy or causal effects. Full article

Pesticides pose significant hazards to aquatic ecosystems and public health; therefore, understanding their fate in aquatic systems is critically important. Photochemical processes driven by direct and indirect photolysis, particularly hydroxyl radical (^•OH) reactions, play a pivotal role in the transformation of these contaminants in natural waters. This study employed an efficient and selective ^•OH production technique using a high-power UV light-emitting diode (UV-LED) combined with nitrite photolysis to determine the second-order reaction rate constants between ^•OH and selected pesticides (k_X,OH). This approach enabled reliable estimation of the indirect photodegradation rate constants (k_IP) for the selected pesticides in aquatic systems. In addition, direct photodegradation rate constants (k_DP) of the selected pesticides were determined under simulated sunlight conditions using a solar simulator equipped with a 500 W xenon lamp. The photochemical half-lives of selected pesticides in river water and seawater were calculated from k_DP and kIP under assumed steady-state HO^• concentrations. The results demonstrated that direct photolysis rate constants of the selected pesticides ranged from 1.62 × 10⁻⁷ to 5.52 × 10⁻⁴ s⁻¹. The second-order reaction rate constants between the investigated pesticides and ^•OH ranged from 0.045 × 10⁹ to 14.8 × 10⁹ M⁻¹ s⁻¹. Estimated half-lives under direct photolysis in seawater ranged from hours to days, whereas half-lives attributed to indirect photolysis in seawater extended to several years. In contrast, half-lives of pesticides in river water ranged from hours to days for indirect photolysis. Under the assumed steady-state ^•OH concentrations, direct photolysis generally produced shorter calculated half-lives than the ^•OH pathway in seawater, whereas the higher assumed ^•OH concentration substantially reduced the calculated indirect-photolysis half-lives in river water. These findings should be interpreted as condition-specific kinetic comparisons rather than direct measurements of environmental persistence. Full article

In this study, laser powder bed fusion (PBF-LB) 022Cr17Ni12Mo2 steel plates with dimensions of 50 mm × 50 mm × 2 mm were fabricated using a laser power of 206 W, a scanning speed of 900 mm/s, a hatch spacing of 90 μm, a layer thickness of 30 μm, and an interlayer scanning rotation of 67°. The specimens were then subjected to solution treatment at 900–1100 °C for 30 min and at 950 °C for 30–120 min. Unlike previous ultrasonic studies on additively manufactured metals, which mainly focused on defect detection, elastic-constant characterization, or residual stress evaluation, this work investigates whether solution-treatment-induced changes in grain size and dislocation density can be quantitatively reflected by laser-ultrasonic attenuation and further correlated with yield strength. Laser ultrasonic nondestructive testing using a 1064 nm pulsed laser with a pulse width of 8 ns and a pulse energy of 500 mJ was combined with metallographic observation, EBSD characterization, XRD analysis, tensile testing, and microhardness measurement. The results show that the solution-treated samples retained a single-phase γ-austenitic structure, while microstructural recovery, weakening of PBF-LB-induced cellular substructures, and partial annihilation of cell-wall dislocations led to a reduction in KAM-derived dislocation density from 2.04 × 10¹⁴ m⁻² to 1.45 × 10¹⁴ m⁻² and a decrease in yield strength from 466.9 MPa to 407.4 MPa. Within the present dataset, the EBSD-equivalent grain size showed an apparent positive correlation with ultrasonic attenuation, while the KAM-derived dislocation density showed an empirical negative correlation with ultrasonic attenuation. However, ultrasonic attenuation should be interpreted as a combined microstructure-sensitive response rather than as a response controlled only by EBSD-equivalent grain size or dislocation density. Based on the empirical correlations among ultrasonic attenuation, EBSD-equivalent grain size, KAM-derived dislocation density, and yield strength, a preliminary attenuation-based calibration model was established for the present solution-treated samples. The model should be regarded as an in-sample empirical calibration within the present experimental range rather than a general Hall–Petch-based predictive model. The model showed good in-sample fitting performance, with (R²) values higher than 0.85 and a maximum in-sample fitting error of 3.85%. However, because the model was established and assessed using the same eight solution-treatment conditions, it should be regarded as a preliminary calibration model within the present experimental range rather than a general predictive model. This study demonstrates the potential of laser ultrasonic attenuation for non-contact evaluation of microstructural and mechanical-property variations in solution-treated PBF-LB 022Cr17Ni12Mo2 steel. Full article

Wind energy, an abundant renewable resource, remains difficult to harness efficiently due to fluctuating speeds and unpredictable directions. In this work, we present a wind bell-inspired triboelectric nanogenerator (WB-TENG) designed for omnidirectional, variable-speed wind harvesting, utilizing layered triboelectric polymers such as polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and polyamide (PA) to enhance energy capture performance. The developed device demonstrates the ability to generate electrical output even under extremely low wind speeds as low as 0.5 m/s. Additionally, it successfully captures wind energy from all directions within a full 360° range. Through structural optimization, the WB-TENG achieves a peak output voltage of 25.1 V and a maximum power of 3.5 μW, representing substantial improvements of 170% and 1232%, respectively, over the performance of our previous prototype. To verify its practical capability, the optimized WB-TENG is employed to power several electronic devices, including a digital watch and 50 commercial LEDs, confirming its potential for real-world energy harvesting applications. This work presents a novel and effective strategy for harnessing wind energy under dynamic environmental conditions, offering a sustainable approach for decentralized energy collection in low-speed and omnidirectional wind settings. Full article

Sustainable building materials development is essential for improving energy efficiency, addressing environmental concerns and optimizing resources use. This study investigates the development and characterization of sorghum stalk fiber-reinforced cement mortar bio-composite for thermal insulation application. Sorghum stalk fiber was added to cement mortar at varying fiber contents (0%, 15%, 30% and 45%), fiber lengths (0.5 cm and 1.5 cm) and varying water–cement ratios (0.4 and 0.6). The composites were characterized for thermal conductivity, thermal diffusivity, density, and compressive and flexural strengths, as well as water absorption and drying kinetics. The result showed that the addition of fiber led to significantly improved thermal insulation performance, accompanied by decreased mechanical strength. The thermal conductivity decreased from 1.57 W/m·K for the control mortar to 0.18 W/m·K (about 88.5% reduction) for 0.5 cm fiber and 0.16 W/m·K (about 89.8% reduction) for 1.5 cm at 45% of fiber. The composite with 15% fiber provided the best balance between thermal and mechanical performance suitable for low load-bearing application, particularly thermal conductivity of 0.90 W/m·K (43% lower) and compressive strength of 10.56 MPa that exceeds the minimum standard to be used in low load-bearing applications; the 30% and 45% fiber composites are suitable for non-structural and thermal insulation applications only. The results obtained demonstrate that the sorghum stalk fiber-reinforced cement mortar is a lightweight, ecological and insulative bio-composite with strong applicability in energy-efficient buildings. Full article

Widespread application of dyes has led to severe threats to water environments, and advanced oxidation processes (AOPs) have been confirmed as an effective solution to dye degradation. Among them, ozonation was one of the most prevalent AOPs. In this study, the effects of using AOPs—mainly based on ozone (O₃)—to treat printing and dyeing wastewater (PDW) were compared. Firstly, ozone carrier active carbon fiber (ACF) was investigated for adsorption performance evaluation on pretreatment. The results showed that ACF treated by ultrasound performed best compared with ACF treated with other four pretreatment methods. Secondly, comparative studies based on individual O₃, ultraviolet (UV), and combined O₃/UV processes on PDW under different pH conditions were conducted. The decolorization rate of reactive brilliant blue X-BR dye under acidic conditions was higher than in alkaline and neutral dyes. In addition, with the utilization of single ozone and O₃/UV under pH = 4 conditions, the decolorization rate could be above 99%. However, individual UV caused few variations in wastewater chromaticity. Thirdly, the effects of pH, UV light intensity, hydraulic retention time (HRT), and ACF filling rate on the performance of the O₃/UV/ACF system were preliminarily screened using a saturated L9 orthogonal design. In terms of the results, the performance of the constructed O₃/UV/ACF AOP system was superior than the conventional oxidation method, in which HRT had the largest apparent main effect on decolorization, followed by pH, ACF filling rate, and UV light intensity. Among the factor levels examined, the best-performing combination was pH 4, a UV power of 48 W, an HRT of 3 h, and an ACF filling rate of 80%. In a subsequent single kinetic experiment conducted using this combination, the final decolorization efficiency was 92.14%, the COD removal was 60%, and the biodegradability increased by 63.08%. This study offered novel insights into an O₃-based AOP system for improving PDW treatment. Full article

Dense Ce,Pr-doped YAG transparent ceramics (YAG:Ce,Pr) with enhanced red emission were fabricated by pressureless sintering in air at 1600 °C. Fine YAG powders containing 0.2 mol% Ce and varying amounts of Pr (0.04–0.32 mol%) were synthesized using a glycine–nitrate combustion method. The emission and excitation spectra were analyzed to investigate the influence of Pr doping on red emission. The results indicate that YAG: Ce,Pr ceramics are a promising candidate for blue-to-yellow light conversion. The strongest red emission component was measured in samples containing 0.16 mol% Pr. It was confirmed that electron transfer from Ce to Pr enhances the red emission component (609 nm), primarily by increasing the population of electrons relaxing from the ¹D₂ excited state to the ³H₄ ground state. Further increasing the Pr concentration beyond 0.16 mol% resulted in a reduction in the red emission intensity due to concentration quenching. Microstructural analysis of YAG:Ce,Pr revealed a dense and homogeneous microstructure composed of equiaxed grains. Full article

The widespread use of domestic LED lamps raises concerns about harmonic current aggregation when multiple units operate in parallel. This study presents a regression-based method for predicting aggregate current waveforms of identical LED lamps. Measurements conducted in accordance with IEC 61000-4-30:2015 involved 1–24 parallel-connected units of a 12 W lamp under controlled conditions. Individual harmonics through the 40th order were assessed against IEC 61000-3-2 product limits, while components up to the 50th order were retained for PCC-oriented characterization of large-scale aggregation, consistent with IEEE 519-2022. Although the product limits were satisfied, measured THD_I remained at 88.6–92%, dominated by the 3rd, 5th, and 7th harmonics. Within the measured range, per-harmonic regressions were evaluated using R² and RMSE, while reconstructed time-domain waveforms produced NRMSE values of 5–10% relative to measured RMS current. Consistent phase angles indicated predominantly constructive aggregation. The model was then applied to an illustrative scenario of up to 100 identical lamps. Under unchanged lamp and supply conditions, the projection indicated a near-linear increase in RMS current, persistent THD_I of approximately 90%, and continued dominance of low-order odd harmonics. Results beyond 24 lamps represent model-based extrapolation rather than experimental validation. The framework provides a baseline for harmonic current assessment in homogeneous LED installations. Full article

This study turns to W.E.B. Du Bois’ late-career works of fiction for insights about the importance of Historically Black Colleges and Universities (HBCUs), especially Black public Land-Grant universities in promoting racial justice in the United States. Commentators often argue that Du Bois’ early career endorsement of the emancipatory power of liberal education and social science research was later abandoned in favor of political activism. The present study challenges this assumption by demonstrating that an important, but generally underappreciated, source of continuity in Du Bois’ thoughts on education was his belief that German-inspired social science research could be a means to combat racial injustice in America. In his major work of fiction, the historical novels The Black Flame Trilogy, Du Bois expounded the positive role Black public universities, and their Presidents have historically played in what he called the “racial uplift” of African American people. Du Bois focuses on the impact of the Second Morrill Act of 1890, which established the legal framework for the system of Black Land-Grant universities and colleges, and which he believed provided the institutional foundations for social science research led primarily but not exclusively by Black scholars in projects that center Black experiences. I conclude with reflections on how Du Bois’ literary representation of the importance of historically Black public universities sheds light on current concerns about state coercion and systematic underfunding of Black Land-Grant Universities. Full article

Background: Ultra-fast high-irradiance curing shortens exposure time, but its effects on conversion and polymer-network integrity may vary among bulk-fill resin composites. This in vitro study was designed as a materials-level investigation of irradiated-surface polymerization behavior. It evaluated irradiated-surface degree of conversion and polymer-network quality while deliberately excluding assessment of depth of cure or polymerization throughout the 4 mm bulk increment. Methods: Eighty disk specimens (6 mm × 4 mm) of Filtek One Bulk Fill, SDR Plus, Beautifil Bulk Flowable, and Beautifil Bulk Restorative (n = 10/material/protocol) were cured with a polywave LED at 1200 mW/cm² for 10 s or 3000 mW/cm² for 3 s. Degree of conversion (DC) was measured by ATR-FTIR on the irradiated (top) surface only. Ethanol-induced softening (ES%, Knoop-hardness reduction at the irradiated surface after 24 h ethanol immersion) served as an inverse, indirect indicator of polymer-network quality (cross-link density). Data were analyzed by two-way ANOVA and Tukey tests (α = 0.05); the DC–ES% relationship was examined by Pearson correlation at the individual-specimen level (n = 80). Results: Ultra-fast curing yielded higher pooled DC (66.30 ± 10.06%) than conventional curing (59.37 ± 7.96%; p < 0.001), but the effect was material-dependent: DC increased significantly for Filtek One Bulk Fill (p < 0.001) and Beautifil Bulk Flowable (p = 0.035), but not for SDR Plus or Beautifil Bulk Restorative. ES% was influenced mainly by material (p < 0.001) and less by curing protocol (p = 0.009). At the specimen level (n = 80), DC and ES% showed a weak but statistically significant negative correlation (r = −0.31, p = 0.006). Conclusions: Within the conditions of this study, irradiated-surface polymerization behavior under ultra-fast curing depended primarily on composite formulation, underscoring the need to evaluate both conversion efficiency and polymer-network quality when optimizing dental restorative materials. Because conversion was assessed only at the irradiated surface, these findings describe irradiated-surface behavior and do not provide evidence of adequate cure at the bottom of the 4 mm increment. Full article

This paper presents a high-efficiency direct-AC LED driver integrating a 14-stage voltage-segmented architecture, digitally coordinated stage selection, and adaptive current-reference regulation. The proposed driver provides finer matching between the rectified bus voltage and the cumulative LED voltage, thereby reducing the residual voltage and power dissipation of the linear regulating devices. Unlike conventional constant-current segmented drivers, the current reference is adjusted according to the selected operating state and the corresponding active LED voltage. A valley-filler circuit is employed to extend the conduction interval of the LED driver and reduce the low-voltage dead zone. A prototype operated at an input voltage of 112.92 V AC and a rated power of approximately 12 W was experimentally evaluated. The measured input power, total LED active power, conversion efficiency, and power factor were 12.12 W, 11.54 W, 95.18%, and 0.9, respectively. The results demonstrate that finer voltage segmentation can reduce voltage-mismatch loss, although the increased number of stages introduces additional component and control complexity. Full article

Laser-directed energy deposition (L-DED) was used to manufacture samples of the newly developed W360 hot-work tool steel from voestalpine Böhler Edelstahl. Various heat-treatment processes, including austenitising followed by air or water-quenching and tempering, as well as direct tempering, were applied. The as-built and heat-treated conditions were characterised by optical microscopy (OM), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD), while the microstructural evolution during austenitisation was investigated using a high-temperature microscope (HTM). Hardness measurements were performed to determine the material response. The as-built condition exhibited a hardness of 628 ± 12 HV with no manufacturing cracks. The highest hardness (666 ± 13 HV) was obtained after air-quenching, whereas water-quenching produced 651 ± 14 HV. The rapid cooling of water-quenching, however, led to the formation of macroscopic cracks. The lattice distortion differences identified by XRD and the kernel average misorientation values obtained from EBSD indicated differences between the air and water-quenched conditions. High hardness (622–628 HV) was retained after low-temperature direct tempering, whereas high-temperature tempering resulted in significant softening (487 ± 12 HV). These results suggest that low-temperature direct tempering is a promising post-processing treatment for L-DED W360 tool steel, although additional mechanical testing is required to confirm industrial applicability. Full article

Continuous monoculture in poplar plantations often leads to declining soil nutrient availability and productivity. Phosphorus (P), in particular, frequently becomes a key limiting factor due to its high fixability and low chemical availability in the soil. Understory vegetation, however, may promote soil P cycling and enhance P availability by regulating the community structure and decomposition activity of soil microorganisms. In this study, a seven-year field experiment was conducted in degraded poplar plantations using a randomized complete block design to investigate the effects of four understory vegetation treatments—understory removal (UR), planting of a nitrogen-fixing species Sesbania cannabina in understory (PN), retention of a single dominant understory species Echinochloa crus-galli (RS), and retention of diverse understory vegetation (RD)—on soil P fractions and availability, and to elucidate the microbial mechanisms driving P cycling using a metagenomic approach. The results showed that, compared with UR, all understory retention treatments significantly increased soil labile P fractions, improved microbial community structure, and enhanced the abundance of P cycling-related functional genes and associated enzyme activities. Specifically, PN enriched the bacterial phylum Chloroflexi, thereby strengthening its role in P cycling, and increased the abundance of key functional genes such as ppa and phnH. These changes led to higher activities of acid phosphatase, phosphodiesterase, and phytase, ultimately improving soil P availability. In contrast, through the input of litter with greater diversity and higher biomass, RD enriched microbial communities dominated by Proteobacteria. This treatment increased the abundance of P cycling-related genes (e.g., phnW, purK, phnP, ugpQ) and associated enzyme activities, thereby enhancing soil P mobilization. Both the introduction of nitrogen-fixing species and the increase in understory species richness promoted soil P cycling and enhanced P availability, albeit through distinct mechanisms. Planting of nitrogen-fixing species enriched specific microbial taxa and functional genes, whereas increasing understory species richness boosts P cycling by increasing bacterial species richness and functional gene abundance. Both enhancing species richness and planting nitrogen-fixing species in the understory effectively improved soil P availability and supported the sustainable management of degraded poplar plantations. Among these approaches, retaining diverse understory vegetation is more cost-effective and contributes to biodiversity conservation, making it a recommended management strategy. Full article

The Kalasayi tungsten deposit is a medium-sized quartz-vein scheelite tungsten deposit in the Western Tianshan, Central Asia Orogenic Belt. The Kalatawu pluton yielded Late Carboniferous zircon U–Pb ages (313.99–310.32 Ma), and molybdenite Re–Os dating gives an isochron age of 302.3 ± 1.8 Ma for W mineralization, indicating an ~8–12 Myr magmatic-hydrothermal system. Whole-rock geochemistry classifies the pluton as aluminous A₂-type granite formed in a post-collisional extensional setting. Zircon Hf isotopes (εHf(t) = +2.8 to +8.3) suggest a mixed juvenile lower crust source with mantle input. In situ LA-ICP-MS scheelite trace element analysis and REE geochemistry distinguish two populations: proximal Group I (high Mo, low Sr, low ΣREE, right-inclined REE patterns) is precipitated from oxidizing magmatic fluid, and distal Group II (low Mo, high Sr, high ΣREE, flat REE patterns, strong positive Eu anomalies) records reduced, mixed fluid with intense fluid–rock interaction. Fluid inclusion data show decreasing temperature and salinity proximally to distally, confirming that mixing of magmatic and meteoric water led to cooling and pH increase that caused W precipitation. A four-stage metallogenic model is proposed for a post-collisional extensional setting, providing robust evidence for A-type granite-related, multi-stage W mineralization and establishing exploration indicators for the southwestern Central Asia Orogenic Belt. Full article

Artificial high-reflectivity ground covers are a potential strategy to increase rear-side irradiance and energy yield in bifacial photovoltaic systems, especially in utility-scale plants with single-axis trackers. This paper reports field evidence from a pilot plant in southern Brazil (27.4° S, 48.4° W), where four reflective covers—a white film, a pearl-white film, a black-and-pearl film, and a white geomembrane—were evaluated against a gray gravel reference. The study combines albedo and spectral characterization, rear-to-front irradiation ratios, energy-yield comparisons, soiling assessment, thermal analysis, and operational observations. Broadband albedo increased from 25% for gray gravel to 53–58% for the reflective films and 72% for the geomembrane. Reflective films increased the rear-to-front irradiation ratio to around 20% and delivered energy gains close to 9%, while the geomembrane achieved the highest irradiance enhancement and gains exceeding 10%. Inverter current limitations led to clipping, indicating that measured gains may underestimate the full energy potential of the reflective covers. Estimated thermal losses were insignificant compared with measured gains, while soiling and fixation methods affected long-term feasibility. The results confirm the technical potential of reflective covers, while showing that utility-scale deployment must consider not only optical performance, but also optical stability, electrical limitations, cleaning and anchoring requirements, drainage adaptations, operation and maintenance practices, and cost constraints. Full article