Search Results (6,570)

The wide application of light emitting diodes (LEDs) in lighting systems has necessitated the inclusion of spectral tunability by using multi-color LED chips. Since the lighting requirement depends on the specific application, it is very important to have flexibility in terms of the driving conditions. While many applications use single or rather white color, some recent applications require multi-spectral lighting systems especially for agricultural or human-medical treatment applications. These systems are underexplored and pose specific challenges. In this paper, a mixture of red, green, blue, white (RGB-W) LED chips was used to develop a compact light engine specifically for agricultural applications. A computational study was performed to understand the optical distribution. Later, attention was turned into development of prototype light engines followed by experimental validation for both the thermal and optical characteristics. Each LED string was driven separately at different current levels enabling an option for obtaining an infinite number of colors for numerous applications. Each LED string on the developed light engine was driven at 300 mA, 500 mA, 700 mA, and 900 mA current levels, and the optical and thermal parameters were recorded simultaneously. A set of computational models and an experimental study were performed to understand the optical and thermal characteristics simultaneously. Full article

Background: This case series study aims to evaluate the spontaneous eruption of impacted canines following diode laser disinclusion surgery without orthodontic traction, and to analyze the correlation with five prognostic factors: age, sex of the patient, angle α, sector, and height of inclusion of the canine. Methods: The sample included 15 patients aged 13–30 years and 20 palatally impacted canines. The patients’ records were collected, and prognostic factors were assessed. All patients underwent disinclusion surgery using a diode laser (K-Laser, Eltech, Blue Derma) and post-surgery, canines were monitored with intraoral scans and photos at 1 week, 8 weeks (T1), and 16 weeks (T2). The STL files were superimposed with the open-source software MeshLab (MeshLab 2023.12, Visual Computing Lab, Pisa, Italy), and the eruption values were measured. Through multiple linear regression analysis, the relationships between the five prognostic factors and the total spontaneous eruption value were analyzed. Results: The canines treated in this study responded with an average eruption of 4.70 mm. For the prognostic factors sex (p = 0.94) and angle α (p = 0.12), no statistically significant relationship with eruption was found. The variables age (p < 0.001), sector II (p = 0.02), sector III (p = 0.03), sector IV (p = 0.06), and inclusion height (p < 0.001) had negative linear coefficients. Consequently, as the values of these three prognostic factors increased, a lower eruption of the included element measured in millimeters was obtained. Conclusions: All canines successfully erupted following the disinclusion procedure, avoiding the use of orthodontic traction. Patient sex and the α angle of impaction were not reliable predictors of eruption outcomes. In contrast, age, sector, and inclusion height measured via CBCT showed high statistical significance and could be used as prognostic factors to predict the eruptive response following disinclusion surgery. Full article

Photobiomodulation (PBM) harnesses near-infrared (NIR) light to stimulate cellular processes, offering non-invasive treatment options for a range of conditions, including chronic wounds, inflammation, and neurological disorders. NIR light-emitting diodes (LEDs) are emerging as safer and more scalable alternatives to conventional lasers, but optimizing their performance for clinical use remains a challenge. This perspective explores the latest advances in NIR-emitting materials, spanning Group III–V, IV, and II–VI semiconductors, organic small molecules, polymers, and perovskites, with an emphasis on their applicability to PBM. Particular attention is given to the promise of perovskite LEDs, including lead-free and lanthanide-doped variants, for delivering narrowband, tunable NIR emission. Furthermore, we examine photonic and plasmonic engineering strategies that enhance light extraction, spectral precision, and device efficiency. By integrating advances in materials science and nanophotonics, it is increasingly feasible to develop flexible, biocompatible, and high-performance NIR LEDs tailored for next-generation therapeutic applications. Full article

Background/Objectives: The laser beam absorption and thermal relaxation time (TRT) in oral tissues are key to optimizing treatment parameters. The aim of this study is to (1) evaluate, in an ex vivo study, the percentage of attenuation and transmittance of each wavelength as a function of tissue thickness; (2) determine the global absorption coefficient, α, of pig gingival tissue for the most commonly used wavelengths in dentistry; (3) calculate the thermal relaxation time (TRT) of oral tissue for these wavelengths; and (4) determine their corresponding penetration depths. Methods: We measured the transmission of different laser wavelengths through pig oral gingival tissues (Mandibular labial gingiva). We placed each tissue sample between two glass slides with minimal light attenuation. The input and output powers were measured after irradiating the tissue at different specific wavelengths: 450 nm, 480 nm, 532 nm, 632 nm, 810 nm, 940 and 980 nm, 1064 nm, 1341, 2780 nm and 2940 nm. After calculating the transmittance values, we plotted transmittance curves for each wavelength. Using the Beer–Lambert law, we then calculated the absorption coefficient (α) of each wavelength in the oral gingival tissue. Absorption coefficients were then used to calculate the TRT and penetration depth for each wavelength. Results: Among the tested wavelengths, 810 nm exhibited the lowest absorption in ex vivo porcine gingival tissue (α = 9.60 cm⁻¹). The 450 nm blue laser showed moderate absorption (α = 26.8 cm⁻¹), while the Er:YAG laser at 2940 nm demonstrated the highest absorption (α = 144.8 cm⁻¹). We ranked the wavelengths from most absorbed to least absorbed by porcine oral gingival mucosa as follows: 2940 nm > 2780 nm > 450 nm > 480 nm > 532 nm > 1341 nm > 632 nm > 940 nm > 980 nm > 1064 nm > 810 nm. Conclusions: Absorption and the TRT vary significantly across wavelengths. Erbium lasers are characterized by the highest absorption and minimal light penetration. Infrared diodes, particularly the 810 nm wavelength, showed the lowest absorption and deepest tissue penetration and exhibited the highest thermal relaxation time. The 480 nm laser demonstrated greater absorption by porcine gingival tissue compared to the 532 nm laser. These findings provide evidence-based guidance for wavelength selection in dental treatments and photobiomodulation, enabling improved precision, safety, and therapeutic efficacy in clinical practice. Full article

In this paper, a novel enhancement-mode β-Ga₂O₃-based FinFET structure with a gate formed by the NiO/β-Ga₂O₃ heterojunction named HJ-FinFET has been proposed, and the excellent performance of the device has also been demonstrated. The primary operational mechanism of this structure involves integrating p-type NiO on both sides of the fin-shaped channel, which forms p-n junctions with β-Ga₂O₃. The depletion regions thus generated are utilized to establish electron channels, enabling enhancement-mode operation. The reverse p-NiO/n-Ga₂O₃ heterojunction diode is integrated to reduce the reverse free-wheeling loss. Compared with the conventional devices, the threshold voltage of the HJ-FinFET is greatly improved, and normally off operation is realized, showing a positive threshold voltage of 2.14 V. Meanwhile, the simulated breakdown voltage of the HJ-FinFET reaches 2.65 kV with specific on-resistance (R_on,sp) of 2.48 mΩ·cm² and the power figure of merit (PFOM = BV²/R_on,sp) reaches 2840 MW/cm², respectively. In addition, the influence of the doping concentration of the heterojunction layer constituting the gate, the doping concentration of the drift layer, and the channel width on the electrical characteristics of the devices were focused on. This structure provides a feasible idea for high-performance β-Ga₂O₃-based FinFET. Full article

This in vivo animal study aimed to evaluate the effects of two different implant placement micromotor systems on implant stability and removal torque. In a within-animal crossover design, twenty titanium implants (AnyOne fixture; internal type; diameter, 3.5 mm; length, 7.0 mm; Megagen, Daegu, Republic of Korea) were placed in the tibiae of five rabbits using a conventional micromotor system (NSK group: SurgicPro+; NSK, Kanuma, Japan) and a diode laser-integrated micromotor system (SAESHIN group: BLP 10; Saeshin, Daegu, Republic of Korea). Resonance frequency analysis provided the implant stability quotient (ISQ) immediately after placement and at four weeks. Micro-computed tomography quantified the bone–implant interface gap (BIG). Removal torque was measured at sacrifice. Linear mixed-effects models with a random intercept for rabbit generated adjusted means with 95% confidence intervals (CIs) (α = 0.05). Equivalence for the four-week ISQ used two one-sided tests with a margin of ±5 ISQ. The SAESHIN group achieved a higher immediate ISQ than the NSK group (difference =+6.9 ISQ; 95% CI +1.3–+12.5; p = 0.018). At four weeks, the ISQ did not differ (difference = −1.2 ISQ; 95% CI −4.3–+1.9; p = 0.42), and equivalence was supported (TOST p_lower = 0.024; p_upper = 0.019). Removal torque was comparable (difference = +4.3 N·cm; 95% CI −5.2–+13.8; p = 0.36). BIG metrics showed no between-system differences across regions. ICC indicated clustering for ISQ and torque (0.36 and 0.31). The diode laser-integrated micromotor system yielded a higher immediate ISQ under a standardized 35 N·cm seating torque, whereas the ISQ, removal torque, and BIG at four weeks were comparable to those of the conventional system. The immediate ISQ should be interpreted as stiffness under fixed torque rather than superior device-dependent interlocking. These findings support the clinical interchangeability of the two systems for early osseointegration endpoints in preclinical settings. Full article

Organic light-emitting diodes (OLEDs) have emerged as a critical battleground in display technology due to their self-emissive and foldable properties. However, the adoption of polyimide (PI) as a flexible substrate material introduces technical challenges, particularly image sticking. This study proposes an interfacial polarization mechanism to explain this phenomenon, confirmed through dielectric and ferroelectric spectroscopy. The results show that introducing an amorphous silicon (α-Si) interlayer significantly improves interface compatibility, increasing the polarization response frequency from 74 Hz to 116 Hz and reducing residual polarization strength from 2.81 nC/cm² to 1.00 nC/cm². Practical tests on OLED devices demonstrate that the optimized structure (PI/α-Si/SiO₂) lowers the image sticking score from 3.46 to 1.67, validating the proposed mechanism. This research provides both theoretical insights and practical solutions for mitigating image sticking in flexible OLED displays. Full article

Native defects significantly impair the electro-optical performance of GaInN/GaN-based light-emitting diodes (LEDs). Therefore, precise characterization of their properties, such as energy levels, capture kinetics, capture cross-sections, and spatial distributions, is crucial for understanding their physical origins following improvement in performance. However, modeling the impact of various defects on the electrical and optical characteristics of LEDs still remains a complex challenge. This study proposes a laser-based measurement technique for the accurate localization and screening of defects in GaInN/GaN-based LEDs by establishing a correlation model between laser excitation and defect response, which enables real-time monitoring of defect dynamics during device degradation, while simultaneously evaluating the effects of the defect state dynamics on the electro-optical characteristics of LED devices. The experimental results indicate that defects located at different spatial positions lead to distinct degradation mechanisms. Full article

Background and Clinical Significance: Cervical ectopic pregnancy (CEP) is a rare and potentially serious condition, in which the embryo implants within the cervical canal rather than the uterine cavity and is present in less than 1% of all ectopic pregnancies. There are different treatment options depending on the particular situation and the woman’s reproductive desire but conservative approaches as the first line of treatment is preferred in all cases and hysteroscopic resection of the fetus is one of these options. Several types of laser systems are available for use in hysteroscopic surgery, including neodymium:YAG (Nd:YAG) lasers, KTP and Argon lasers, as well as diode lasers. The holmium:YAG (Ho:YAG) laser, although more commonly used in urology due to its ability to cut, coagulate, and vaporize tissue, has gained interest in gynecologic procedures because of its precision and favorable safety profile. Case Presentation: We present the case of a 32-year-old woman, pregnant for the first time, who was diagnosed with CEP and successfully treated using a Ho:YAG laser during an outpatient hysteroscopic procedure. As far as we know, this is the first published case using this approach. Conclusions: The Ho:YAG laser is a proven tool for outpatient hysteroscopic procedures like septum and adhesion removal. Its ability to both cut and coagulate offers a minimally invasive, fertility-sparing option for managing cervical ectopic pregnancy. With the right patient and proper backup plans in place, this approach could be a promising alternative to more aggressive treatments. Full article

Visible Light Positioning (VLP), leveraging Light-Emitting Diodes (LEDs) and smartphone CMOS cameras, provides a high-precision solution for indoor localization. However, existing systems face challenges in accuracy, latency, and robustness due to line-of-sight (LOS) limitations and inefficient signal encoding. To overcome these constraints, this paper introduces a real-time VLP framework that integrates Multi-Pulse Position Modulation (MPPM) with smartphone multi-sensor fusion. By employing MPPM, a high-efficiency encoding scheme, the proposed system transmits LED identifiers (LED-IDs) with reduced inter-symbol interference, enabling robust signal detection even under dynamic lighting conditions and at extended distances. The smartphone’s camera is a receiver that decodes the MPPM-encoded LED-ID, while accelerometer and magnetometer data compensate for device orientation and motion-induced errors. Experimental results demonstrate that the MPPM-driven approach achieves a decoding success rate of over 97% at distances up to 2.4 m, while maintaining a frame processing rate of 30 FPS and sub-35 ms latency. Furthermore, the method reduces angular errors through sensor fusion, yielding 2D positioning accuracy below 10 cm and vertical errors under 16 cm across diverse smartphone orientations. The synergy of MPPM’s spectral efficiency and multi-sensor correction establishes a new benchmark for VLP systems, enabling scalable deployment in real-world environments without requiring complex infrastructure. Full article

Advances in OLED display technology have increased the demand for high-performance luminescent materials, yet efficient red emitters with narrow emission spectra remain rare. Here, two new polycyclic compounds (O-QA and S-QA) are designed by incorporating oxygen/sulfur into a carbonyl/nitrogen skeleton. Photophysical and theoretical studies reveal their hybridized local and charge-transfer state characteristics. In toluene, O-QA and S-QA show photoluminescence peaks at 586/579 nm with narrow emission spectra, while doped films exhibit strong red emissions peaking at 598/600 nm with high PL quantum yields of 67%/60%. The OLEDs using these emitters achieve red electroluminescence (EL) peaks at 598/602 nm, and attain maximum external quantum efficiencies of 7.36%/14.54%. This work may provide guidance for the development of narrow-spectrum red emitters based on carbonyl/nitrogen frameworks. Full article

Cocoa pod husk (CPH), the principal by-product of cocoa processing, represents an abundant and underutilized source of bioactive phenolics with potential applications in the food and nutraceutical sectors. This study optimized the extraction of catechin, epicatechin, procyanidin B2, and clovamide from CPH (CCN-51 variety) using microwave-assisted extraction (MAE) and evaluated the influence of drying temperature on their retention. A Box–Behnken design within a response surface methodology framework was employed to evaluate the effects of ethanol concentration (0–100%), extraction temperature (50–150 °C), and extraction time (15–60 min) on compound recovery. The phenolic profile was characterized by high-performance liquid chromatography with diode-array detection and electrospray ionization ion trap tandem mass spectrometry. Optimal MAE conditions of 51% ethanol, 104 °C, and 38 min yielded maximum concentrations of clovamide, procyanidin B2, and epicatechin of 3440, 908, and 445 mg/kg dry matter of cocoa pod husk, respectively. Drying studies demonstrated that moderate hot-air temperatures (40–50 °C) preserved the highest phenolic levels. These results underscore the importance of optimizing both extraction and drying conditions to enhance the recovery of phenolic compounds from cocoa processing residues, supporting their potential valorization as antioxidant-rich functional ingredients. Full article

Illyrian iris (Iris pallida subsp. illyrica (Tomm. ex Vis.) K.Richt.) is a rhizomatous geophyte, an endemic species (subspecies), occurring within a limited range along the eastern coast of the Adriatic Sea. The study presents the first in-depth chemical and functional investigation of its rhizome extracts using both conventional and greener solvents, as well as essential oil (EO) via hydrodistillation, employing gas chromatography-mass spectrometry (GC/MS) and ultra-high-performance liquid chromatography-diode array detector-tandem mass spectrometry (UHPLC-DAD-MS/MS) for metabolic fingerprinting, which was further interpreted through a chemosensory lens. High-performance thin-layer chromatography (HPTLC) bioautography (HPTLC-DPPH/ HPTLC-Tyrosinase) was applied for the first time to this species, revealing zones of bioactivity. HaCaT cell viability and spectrophotometric assays were employed to further evaluate the cosmetic potential. Results showed a distinctive volatile profile of EO, including, to the best of our knowledge, the first identification of a silphiperfol-type sesquiterpenoid in the Illyrian iris rhizome. UHPLC-DAD-MS/MS and HPTLC fingerprinting further supported solvent-dependent differences in metabolite composition. Notably, acetone, ethyl acetate, and ethanol extracts exhibited similar chemical profiles, while greener extracts showed more divergent patterns. The results provide a foundation for the future exploration of Illyrian iris in sustainable cosmetic applications, emphasizing the need for further in vitro and in vivo validation. Full article

Many cases have been described where the combination of semiochemicals and light sources in traps cause an increase in adult insect attraction. In this context, we tested different treatments using Delta plastic traps to catch DBM adults: (1) dispensers containing DBM SSA; (2) UV (365–370 nm) LEDs; (3) a combination of a dispenser containing DBM SSA and LEDs (SSA + LED); and (4) no lures (Control). The trials were conducted in northwestern Russia (the vicinity of St. Petersburg) during the period of 2022–2024 on cabbage crops. The results showed a highly significant interaction between SSA and LEDs with respect to their attractiveness to male DBM adults, as evidenced by an average 15-fold increase in DBM captures after the traps containing SSA were equipped with a second lure, an LED. This article discusses the prospects for using the identified synergistic effect of interaction between SSA and LEDs to enhance the catch of DBM adults for practical purposes, such as improving monitoring and developing more effective mass-trapping technologies. Full article

Blood glucose monitoring is crucial for the daily management of diabetic patients. In this study, we developed a differential absorbance and photoplethysmography (PPG)-based non-invasive blood glucose measurement system (NIBGMS) using visible–near-infrared (Vis-NIR) light. Three light-emitting diodes (LEDs) (625 nm, 850 nm, and 940 nm) and three photodetectors (PDs) with different source–detector separation distances were used to detect the differential absorbance of tissues at different depths and PPG signals of the index finger. A spatiotemporal multimodal fused long short-term memory (STMF-LSTM) model was developed to improve the prediction accuracy of blood glucose levels by multimodal fusion of optical spatial information (differential absorbance and PPG signals) and glucose temporal information. The validity of the NIBGMS was preliminarily verified using multilayer perceptron (MLP), support vector regression (SVR), random forest regression (RFR), and extreme gradient boosting (XG Boost) models on datasets collected from 15 non-diabetic subjects and 3 type-2 diabetic subjects, with a total of 805 samples. Additionally, a continuous dataset consisting 272 samples from four non-diabetic subjects was used to validate the developed STMF-LSTM model. The results demonstrate that the STMF-LSTM model indicated improved prediction performance with a root mean square error (RMSE) of 0.811 mmol/L and a percentage of 100% for Parkes error grid analysis (EGA) Zone A and B in 8-fold cross validation. Therefore, the developed NIBGMS and STMF-LSTM model show potential in practical non-invasive blood glucose monitoring. Full article