Search Results (1,916)

High-power-density LED devices have emerged as a prominent focus in current research and industrial development, largely due to their role in advancing LED lighting technologies. At high power and high current, the structure and area of the thermoelectrically separated copper substrate connected to the LEDs significantly influence the device’s optoelectronic performance, yet detailed studies in this area remain limited. To address this issue, blue and white LED devices with a maximum power rating of 400 W were fabricated and soldered onto copper substrates with diameters of 20 mm, 25 mm, and 32 mm. The influence of substrate area on the I–V and I–L characteristics of the LEDs was systematically measured and analyzed at different operating temperatures. Additionally, variations in operating voltage and luminous intensity with temperature were investigated under specific driving currents. Infrared thermal imaging was employed to examine the thermal field distribution under varying substrate sizes and current levels. The results show that increasing the copper substrate diameter from 20 mm to 25 mm and further to 32 mm leads to a significant improvement in LED optoelectronic performance. To determine the diameter threshold beyond which performance gains diminish, a 3D COMSOL 6.1. model was developed. The model reveals that expanding the diameter from 32 mm to 35 mm results in only a marginal improvement, while further increasing it to 40 mm offers a negligible additional benefit, thereby identifying the optimal substrate area for performance saturation. Full article

Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) have emerged as promising candidates for next-generation large-area and low-power electronics due to their high mobility, low leakage current, and compatibility with low-temperature fabrication on flexible or transparent substrates. In this work, we report the fabrication of bottom-gate a-IGZO NMOS TFTs using HfO₂ as high-k gate dielectric and Mo top contacts. The devices were electrically characterized through capacitance–voltage (C–V) and current–voltage (I–V) measurements, from which key parameters were extracted. Based on these transistors, we designed, fabricated, and characterized inverters employing four different load configurations: resistive, diode, depletion, and pseudo-CMOS. A comparative analysis was performed in terms of voltage transfer characteristics (VTCs), gain, and noise margins, highlighting that depletion-load inverters offer the highest gain and robust noise margins. Finally, a two-channel multiplexer was designed and fabricated. The multiplexer was characterized under both square and sinusoidal input signals up to 1 kHz, demonstrating correct channel selection and robust switching behavior. These results confirm the potential of a-IGZO TFT-based circuits as building blocks for low-power and high-reliability digital and mixed-signal electronics. Full article

The maturation of distilled spirits in wooden barrels is a critical process that defines the sensory profile and quality of the final product, primarily through the release of polyphenols and flavonoids. In this study, the early extraction kinetics of these compounds in agave distillates were investigated using laboratory-scale barrels (5 L) with three toasting levels: light (185 °C/60 s), medium (210 °C/90 s), and intense (235 °C/120 s). The barrels were characterized by FTIR and Raman spectroscopy (SEM), as well as Scanning Electron Microscopy to correlate the chemical structure of the wood with the release of phenolic compounds. For this purpose, the Electrochemical Color Index (ECI), representative of polyphenols and flavonoids, was monitored daily for over 60 days. Results showed no statistically significant differences (p > 0.05) among the toasting levels. On the other hand, the observed kinetics exhibited four characteristic phases: (i) a linear increase during the first week due to the extraction of the most exposed compounds, (ii) a partial decrease in the second week associated with the re-adsorption of extracted compounds onto active sites remaining available on the barrel surface, (iii) a pseudo-steady state up to day 60, and finally, (iv) a subsequent linear increase. These findings provide scientific evidence supporting the official standards for the classification of aged distillates, since at least 60 days are required to condition the barrel surface to achieve a balanced extraction of polyphenols and flavonoids. The results highlight ECI as a robust and sensitive tool for monitoring the early maturation of agave distillates. Furthermore, the proposed approach not only offers complementary analytical criteria but also contributes to supporting the regulatory definitions of the reposado category, providing a practical framework for process standardization. Full article

Tin selenide (SnSe) is a sustainable, lead-free IV–VI semiconductor whose layered orthorhombic crystal structure induces pronounced electronic and phononic anisotropy, enabling diverse energy-related functionalities. This review systematically summarizes recent progress in understanding the structure–property–processing relationships that govern SnSe performance in thermoelectric and optoelectronic applications. Key crystallographic characteristics are first discussed, including the temperature-driven Pnma–Cmcm phase transition, anisotropic band and valley structures, and phonon transport mechanisms that lead to intrinsically low lattice thermal conductivity below 0.5 W m⁻¹ K⁻¹ and tunable carrier transport. Subsequently, major synthesis strategies are critically compared, spanning Bridgman and vertical-gradient single-crystal growth, spark plasma sintering and hot pressing of polycrystals, as well as vapor- and solution-based thin-film fabrication, with emphasis on process windows, stoichiometry control, defect chemistry, and microstructure engineering. For thermoelectric applications, directional and temperature-dependent transport behaviors are analyzed, highlighting record thermoelectric performance in single-crystal SnSe at hi. We analyze directional and temperature-dependent transport, highlighting record thermoelectric figure of merit values exceeding 2.6 along the b-axis in single-crystal SnSe at ~900 K, as well as recent progress in polycrystalline and thin-film systems through alkali/coinage-metal doping (Ag, Na, Cu), isovalent and heterovalent substitution (Zn, S), and hierarchical microstructural design. For optoelectronic applications, optical properties, carrier dynamics, and photoresponse characteristics are summarized, underscoring high absorption coefficients exceeding 10⁴ cm⁻¹ and bandgap tunability across the visible to near-infrared range, together with interface engineering strategies for thin-film photovoltaics and broadband photodetectors. Emerging applications beyond energy conversion, including phase-change memory and electrochemical energy storage, are also reviewed. Finally, key challenges related to selenium volatility, performance reproducibility, long-term stability, and scalable manufacturing are identified. Overall, this review provides a process-oriented and application-driven framework to guide the rational design, synthesis optimization, and device integration of SnSe-based materials. Full article

Background/Objectives: Advances in pediatric oncology have improved survival; however, critically ill children with cancer remain at high risk for adverse outcomes and frequently require admission to the pediatric intensive care unit (PICU). Despite the rising burden of pediatric cancer in Saudi Arabia, data on PICU utilization and outcomes remain limited. This study aimed to describe the clinical characteristics, critical care interventions, and outcomes of pediatric oncology patients admitted to a tertiary PICU and to identify predictors of mortality. Methods: This is a retrospective cohort study was conducted including pediatric oncology patients (<14 years) admitted to the PICU at King Abdullah Specialized Children’s Hospital, Riyadh, between 2015 and 2021. Demographic, oncologic, and clinical variables; admission indications; PRISM-IV scores; and PICU interventions were collected. Predictors of mortality were evaluated using Cox proportional hazards modeling. Results: A total of 126 pediatric oncology patients were admitted to the PICU during the study period. The median age was 6 years (IQR 3–11), and 59% were female. Hematologic malignancies accounted for 63% of admissions. Sepsis (41%) and respiratory failure (21%) were the leading indications for PICU admission. Comorbidities were present in 33% of patients, and 70% had received prior therapeutic interventions, most commonly chemotherapy. Organ dysfunction occurred in 39% of patients, including 32% with multiorgan failure. Mechanical ventilation was required in 35% of patients, vasopressor support in 30%, and dialysis in a smaller proportion. The overall mortality rate was 19%, with more than half of deaths occurring during the PICU stay. Non-survivors had higher rates of comorbidities and invasive organ support, and higher PRISM scores. Mechanical ventilation (HR 3.02; 95% CI 1.16–7.60) and prior therapeutic interventions (HR 3.19; 95% CI 1.24–8.19) were independent predictors of mortality. Conclusions: Pediatric oncology patients admitted to the PICU experience substantial morbidity and mortality, underscoring the need for early risk identification and optimized supportive care. Full article

An elevated somatic cell count (SCC) affects the physicochemical characteristics of milk, altering its renneting ability and ultimately impacting the yield and quality of the cheese produced. This study aims to analyse the variations in the composition of Latvian goat milk and its technological properties in relation to SCC. Individual goat milk samples (n = 240) were collected from one of the largest goat farms in Latvia during 2019 and 2020. Latvian, Saanen, and cross-breed goat milk samples from different lactations were tested for their chemical composition (fat, protein, lactose, dry matter, and SCC), fat-to-protein ratio, freezing point, and curd firmness. Samples were collected during different lactation periods in order to analyse the seasonal effect on milk quality. The results demonstrated that milk samples from goats with lower SCCs (Group I) exhibited the highest fat (3.34%), lactose (4.56%), and dry matter (11.28%) concentrations and fat-to-protein ratios (1.02). Curd firmness decreased progressively from Group I to Group IV, fluctuating between Latvian Native (1.96–1.47 N), Saanen (1.91–1.59 N), and cross-breed (1.66–1.58 N) goat milk samples. A significantly lower (p = 0.030) curd firmness (1.56 N) was determined in the Group IV goat milk samples. Seasonal fluctuations in milk composition were observed in relation to curd firmness, which peaked in late lactation milk (3.85 N), although minor fluctuations were observed in protein concentrations (3.23% to 3.30%) across the sampling periods (2019 and 2020). These findings highlight the necessity of SCC monitoring in Latvian goat milk to ensure appropriate quality for milk processing. Full article

Reticulated acanthoma with sebaceous differentiation (RASD) is a rare, benign cutaneous neoplasm. Its variable clinical presentation frequently mimics both benign and malignant entities, posing a significant diagnostic challenge. We report a case of pigmented RASD in a 78-year-old Malay male of Fitzpatrick skin type IV who presented with a 5-year history of an 8 × 5 mm deeply pigmented, asymmetrical nodule on the left upper back, with a 2 mm central raised area showing less pigmentation. The lesion was clinically suspicious for malignant melanoma. Histopathological examination revealed characteristic features of RASD: a broad, plate-like, reticulated and pigmented epidermal proliferation with clusters of mature sebocytes at the bases of anastomosing rete ridges. Following biopsy confirmation, the residual lesion is being managed conservatively with observation. This case demonstrates an unusual heavily pigmented clinical presentation that completely obscured the typical yellowish hue associated with sebaceous differentiation, highlighting pigmented RASD as an important diagnostic pitfall in patients with skin of color. In conclusion, RASD should be included in the differential diagnosis of pigmented cutaneous lesions, especially in patients with skin of color. Recognition of this benign entity can prevent unnecessary aggressive surgical intervention. Full article

This article describes the design, control, and implementation of a photovoltaic (PV) emulator using two-switch forward-converter topology. The system is designed to emulate the nonlinear electrical behavior of an actual PV panel under different environmental conditions including radiation level and temperature. The emulator provides galvanic isolation and also accurate current modulation to provide a safe yet reliable means of testing PV-related devices and algorithms within a laboratory setting. A dual-loop PI control is proposed to adjust the output current according to voltage feedback (VF), thus making accurate I–V and P–V curves achievable. Besides software simulation, a tailored printed circuit board (PCB) was fabricated. The simulation result demonstrated that the system can achieve a fast response and stable operation, with a maximum error percentage of about 2.1%, indicating high emulation fidelity, thereby providing an attractive platform for various evaluation purposes such as MPPT algorithms, inverters, and EMS. Full article

Woody debris decomposition is a key process in forest ecosystem material cycles, with invertebrate communities playing a vital role. Distinct physicochemical properties of woody debris types lead to varying effects on these communities. Taking woody debris in Saihanba’s Larix principis-rupprechtii plantations, Betula platyphylla natural secondary forests, and larch–birch mixed forests (northern China) as objects, we collected woody debris-inhabiting invertebrates via hand-sorting. We studied how tree species (larch/birch), forest types (pure/mixed), and decay stages (I–V) collectively regulate invertebrate community assembly. Results showed significant differences in woody debris physicochemical properties across these factors. Phytophagous groups dominated early decay stages (I–III) and decreased significantly (p < 0.05) with reduced wood density. In contrast, saprophagous and predatory groups increased with decay, correlated with higher TN and were more abundant in mixed than pure forests. NMDS indicated significant community differences among tree species/forest types in early decay, converging later. PLS-PM further confirmed functional groups’ response pathways to woody debris characteristics. Thus, preserving woody debris integrity and diversity in plantations is crucial for maintaining invertebrate diversity, promoting nutrient cycling, and enhancing forest ecosystem functions. Full article

Objectives: The lymph node yield of a curative neck dissection for advanced head and neck squamous cell carcinoma (HNSCC) is an important factor in improving patient outcomes. Achieving adequate resection while minimising surgical risk is important. This retrospective study investigated the role of the lymph node yield for the survival of patients with HNSCC. Methods: A total of 234 patients with advanced HNSCC who were treated at a German university hospital between 1997 and 2018 were analysed. The analysis included patient data, tumour-specific characteristics, and the extent of neck dissection performed. Statistical analysis was performed using multivariate Cox proportional hazards models, supplemented by Kaplan–Meier analyses. Results: The median age was 60.0 years (range: 30–85 years, interquartile range: 12.3 years). The follow-up period covered up to 25 years. According to the Union for International Cancer Control, n = 64 patients had UICC-stage III, and 170 patients had UICC-stage IV. The above-average lymph node yield was superior to average, but especially to below-average lymph node yields in bilateral (2.9-fold), ipsilateral (2.6-fold), and contralateral (10.7-fold) neck dissection. In particular, contralateral neck dissection was found to correlate with a significantly better prognosis in terms of overall survival when a higher number of lymph nodes were removed. Conclusions: The study suggests that a thorough and careful neck dissection involving the removal of a greater number of lymph nodes and including the contralateral side could significantly improve the survival for patients with advanced HNSCC. Full article

Dust accumulation on photovoltaic (PV) modules is a major factor contributing to reduced power output, lower efficiency, and accelerated material degradation, particularly in arid and industrialized regions. This study presents a comprehensive review and analysis of the influence of dust deposition on PV performance, covering its optical, thermal, and electrical impacts. Findings from global literature indicate that dust-induced efficiency losses typically range from 10% to 70%, depending on particle characteristics, environmental conditions, and surface orientation. Experimental and modeled I–V and P–V characteristics further reveal significant declines in current and power output as soiling levels increase. Through an extensive literature assessment, this paper identifies Machine Learning (ML)-based approaches as emerging and highly effective techniques for dust detection and mitigation. Recent studies demonstrate the integration of image processing, drone-assisted monitoring, and convolutional neural networks (CNNs) to enable automated, real-time soiling assessment. These intelligent methods outperform conventional manual and time-based cleaning strategies in accuracy, scalability, and cost efficiency. By synthesizing current research trends, this review highlights the growing role of ML and data-driven technologies in enhancing PV system reliability, informing predictive maintenance, and supporting sustainable solar energy generation. Full article

Background: Right-ventricular (RV) involvement is starting to gain recognition in pediatric dilated cardiomyopathy (DCM), but its deformation characteristics and its relationship to functional status remain insufficiently defined. Methods: Twenty-nine children with primary DCM were compared with age- and sex-matched healthy controls. Conventional echocardiography and two-dimensional speckle-tracking echocardiography (2D-STE) were performed. Segmental deformation (basal, mid-ventricular and apical levels) was analyzed using a linear mixed-effects model. Associations between strain indices and advanced functional limitation (NYHA/Ross Class III-IV) were evaluated using exploratory logistic regression and ROC analysis. Results: Children with DCM showed significant impairment in both ventricles. Conventional parameters (TAPSE, tricuspid E/A ratio, RV E′ velocity, and LV ejection fraction) were reduced. Right ventricular strain was significantly lower in DCM compared with controls (p < 0.05). Segmental analysis demonstrated a basal-predominant reduction in RV strain. Right-ventricular free-wall longitudinal strain correlated with RV S′ (r = −0.49), RV E′ (r = −0.46), LVGLS (r = 0.79) and LV ejection fraction (r = −0.63, all p < 0.05). In univariable analysis, RVFWSL predicted advanced functional class (OR 1.13 per 1% decrease, p = 0.026), while LVGLS remained the independent predictor in the multivariable model. A combined model incorporating RVFWSL and LVGLS demonstrated excellent discriminative accuracy (AUC 0.95). Conclusions: Pediatric DCM is characterized by RV involvement with a distinct basal-dominant deformation pattern. Biventricular strain assessment improves the identification of children with advanced functional class and may enhance functional stratification beyond conventional indices. Full article

Accurate monitoring of shaft voltages and bearing currents in large turbo-generators is essential for promoting the sustainable operation of critical power infrastructure. Conventional monitoring systems often rely on threshold triggers that fail to identify early-stage degradation in shaft-earthing brushes. This paper presents an advanced diagnostic approach based on real-time shaft voltage and current measurements collected from four large utility-scale steam turbine generators. Through detailed analysis of time-domain waveforms, frequency-domain spectra, and current scatter plots, characteristic electrical signatures were established for four operational case studies for faults: (i) a floating voltage brush, (ii) a floating current brush, (iii) a worn brush, and (iv) oil/dust contamination. This study demonstrates that each fault produces a distinctive pattern, such as the suppressed RMS shaft voltage with transient spikes in floating voltage brushes, elevated DC offsets and even-order harmonics in floating current brushes, erratic waveforms and intermittent surges in worn brushes, and elevated DC bias with increased current under contamination. These findings establish actionable thresholds for predictive maintenance, fostering enhanced reliability, optimized asset life, and reduced maintenance-related environmental impact. Full article

Background/Objectives: Comprehensive genomic profiling (CGP) is a cornerstone of personalized oncology. However, large-scale, systematic data on the somatic mutation spectrum in Russian cancer patients are scarce. This study aimed to characterize the genomic landscape and assess the potential for matched therapy in a Russian cohort of patients with solid tumors. Methods: This retrospective study included 204 patients with various solid tumors. CGP was performed using the FoundationOne^®CDx (FFPE tissue) and FoundationOne^®Liquid CDx (cfDNA) platforms. The analysis assessed single-nucleotide variants, indels, copy number alterations, gene fusions, tumor mutational burden (TMB), microsatellite instability (MSI), and PD-L1 expression. Results: The most frequently mutated genes were TP53 (61.5%) and KRAS. The median TMB was 4.0 mut/Mb and was significantly lower in stage IV tumors. Significant co-occurrence was observed between KRAS and TP53 mutations, as well as between APC and KRAS mutations, which were particularly characteristic of colorectal cancer. KRAS mutations were associated with higher combined positive score (CPS) values in cases with lung cancer. Based on the CGP results, 44% of patients had findings that supported the use of an approved matched targeted therapy or immunotherapy for their tumor type. An additional 36% of patients had alterations indicating potential benefit from off-label targeted therapy. Conclusions: This study reveals the distinct genomic characteristics of solid tumors in a Russian cohort and confirms the high clinical utility of CGP for identifying actionable targets. Implementing CGP early in the diagnostic process is a necessary step towards realizing personalized treatment strategies for cancer patients. Full article

This study aims to investigate hydrogeochemical characteristics and groundwater quality in the Bashang Area in Chengde and to discuss factors controlling the groundwater quality. A total of 91 groundwater samples were collected and a fuzzy synthetic evaluation (FSE) method was used for assessing groundwater quality. Results show the groundwater chemistry in the study area is predominantly characterized by HCO₃⁻-Ca type waters. Rock weathering processes dominate the hydrogeochemical processes within the study area, while also being influenced by evaporation and concentration effects. The results of the fuzzy evaluation indicate that 94.5% of groundwater samples are of good quality and suitable for drinking (Classes I, II, and III), while 5.5% are of poor quality and unsuitable for drinking (Class IV). Among these, bedrock fissure water exhibited superior quality. Within clastic rock pore water, elevated levels of NO₃⁻ and F⁻ ions were observed in certain localized areas. The exceedance of NO₃⁻ concentrations stems from agricultural expansion, where the application of nitrogen fertilizers constitutes the primary driver of local nitrate pollution. Excessive F⁻ levels correlate with the region’s indigenous geological background. Fluoride-bearing minerals such as fluorite and biotite are widely distributed throughout the study area. Intensive evaporation concentrates groundwater, while the region’s slow groundwater flow facilitates the accumulation and enrichment of F⁻ within aquifers. Full article