Search Results (1,934)

Musculoskeletal pain is a major cause of disability and long-term analgesic use, increasing interest in safe non-pharmacological interventions. This focused narrative review examines light-emitting diode (LED)-based photobiomodulation (PBM) for musculoskeletal pain, integrating molecular, mechanistic, clinical, and translational evidence. Red and near-infrared LED-PBM may act through mitochondrial and non-mitochondrial photoacceptors, modulation of ATP production, reactive oxygen species, nitric oxide, calcium signaling, inflammatory pathways, oxidative stress responses, and extracellular matrix repair. Clinical evidence suggests a potential benefit in selected conditions, particularly temporomandibular disorders, fibromyalgia, cervical and myofascial pain, tendon and plantar fascia disorders, knee osteoarthritis, and mild-to-moderate peripheral nerve compression, while findings for non-specific low back pain remain inconsistent. The reviewed literature indicates that therapeutic response depends less on emitter identity alone than on wavelength, irradiance, radiant exposure, treatment geometry, target depth, timing, disease phenotype, and protocol quality. LED-based PBM appears generally well tolerated and clinically promising as an adjunct to rehabilitation, but current evidence is limited by heterogeneous devices, incomplete dosimetry, variable comparators, and short follow-up. Future studies should prioritize standardized reporting, depth-aware dosing, phenotype-based recruitment, biomarker-linked outcomes, and direct laser–LED comparisons under dosimetrically matched conditions. Full article

Repeated low-level red light (RLRL) has been reported to control myopia progression clinically. Given safety concerns with laser sources, light-emitting diodes (LED)-sourced red light represents a promising alternative. This study investigated the effects of LED-sourced red light (RL) on cellular response in vitro and ocular growth in normal and lens-induced myopic chicks. In vitro, the mouse photoreceptor 661W cell line was exposed to 625 and 664 nm LED-sourced RL (3 min, twice daily) for 3 days, and cytochrome c oxidase (CCO) activity and cell viability were assessed. In vivo, chicks were randomly assigned to normal visual conditions or monocular −5D lens-induced myopia (LIM). Treatment groups received 664 nm LED-sourced RL (30 min, twice daily) at low, moderate, or high intensities for 10 days. In vitro, LED-sourced RL at 664 nm more effectively activated CCO and enhanced cell viability in 661W cells than RL at 625 nm and white light. In vivo, low-intensity RL exposure of 10 days significantly inhibited vitreous chamber depth (VCD) and axial length (AL) elongation compared to the normal light group (p < 0.05) in normally growing chicks but showed no significant effect in LIM eyes. By contrast, moderate- and high-intensity RL exposure for 10 days attenuated myopia progression in LIM eyes, as reflected by slower VCD and AL elongation and less myopic shift, compared to the normal light group (all p < 0.05). Notably, high-intensity RL also protected the untouched fellow eyes of the LIM chick models against myopic shift and excessive elongation. LED-sourced RL at 664 nm was effective in activating CCO, reducing apoptosis, and promoting cell viability. In chick models, it can also inhibit ocular growth in both normally growing and −5D lens-induced myopic chicks. Full article

The oral cavity harbors a complex microbial community where pathogens implicated in dental caries and periodontitis can heavily colonize toothbrushes, transforming them into persistent sources of contamination that threaten both oral and systemic health. Consequently, this study evaluated the bactericidal efficacy of 275 nm ultraviolet light-emitting diode (UV-LED) irradiation against common oral bacteria in vitro and its practical utility for extraoral toothbrush sanitization. Suspensions of Streptococcus mutans, Streptococcus sanguinis, Porphyromonas gingivalis, and Fusobacterium nucleatum were irradiated for 3 min, 6 min, and 9 min. Bacterial growth and bactericidal effects were measured using growth curve and colony-forming unit assays, respectively. LIVE/DEAD staining and crystal violet staining were used to evaluate the bacterial viability and multispecies biofilm formation after irradiation. Additionally, the sanitization effects of a 275 nm UVC-based portable device on used toothbrushes were investigated. Direct UVC irradiation at 275 nm exhibited strong bactericidal effects against common oral bacteria in vitro. UVC irradiation also showed great sanitization effects on used toothbrushes. In summary, the vulnerability of common oral bacteria to 275 nm UVC, combined with its sanitizing efficacy on used toothbrushes, establishes a solid basis for extraoral sanitization, offering a reliable strategy to mitigate the risk of oral pathogen transmission from contaminated toothbrushes. Full article

Living wall systems are increasingly used in indoor environments as elements of biophilic design; however, plant growth in these systems relies almost entirely on artificial lighting. While light-emitting diode (LED) technology offers flexible spectral properties, limited information is available on how commercially available white LEDs with different correlated color temperatures (CCTs) affect plant performance in indoor vertical greenery systems. The present study evaluated the effects of three white LED lamps differing in CCT, specifically warm-white (2700 K), neutral-white (4000 K), and cool-white (6500 K), on the growth, flowering, physiological performance, and visual perception of Spathiphyllum wallisii Regel cultivated in an indoor living wall system under exclusively artificial lighting. Plants were grown for eight months under a 12 h photoperiod, and growth parameters, flowering, SPAD index, photosystem II efficiency (F_v/F_m), and biomass accumulation were assessed. In addition, a questionnaire survey evaluated visual preferences under the different lighting conditions. Plant growth parameters, flowering, and physiological performance were largely unaffected by CCT, indicating that S. wallisii can adapt to a wide range of white LED spectra under low-irradiance conditions (~16–18 μmol m⁻² s⁻¹). However, cool-white lighting was associated with slightly higher canopy coverage and aboveground biomass compared to other treatments, although overall differences among CCTs were relatively limited. In contrast, survey results indicated a clear preference for neutral-white lighting, which was most frequently perceived as providing the most natural plant appearance and the most suitable illumination for indoor living walls. These findings suggest that neutral-white LEDs may provide a suitable balance between maintaining satisfactory plant growth and achieving favorable visual perception in indoor greenery installations. Full article

Perovskite light-emitting diodes (PeLEDs) have attracted considerable attention due to their outstanding electroluminescent properties and have achieved remarkable progress. However, charge injection imbalance remains a major obstacle limiting the performance of near-infrared (NIR) PeLEDs. Herein, we propose inserting a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) buffer layer between ITO and Zinc oxide (ZnO) to reduce electron injection. This layer also acts as a substrate to modulate ZnO surface roughness, thereby improving perovskite film quality. Through this optimization, the device’s external quantum efficiency (EQE) increases from 20% to 22%, and its T₅₀ operational lifetime extends from 3.4 h to 17.8 h. Importantly, we successfully integrate the PEDOT:PSS buffer layer into scalable fabrication, demonstrating NIR-PeLEDs with a uniform emission area of 2500 mm². Full article

This study assessed the effects of different intensities of broad-spectrum white LED light (PAR range: 415–748 nm) on growth, fucoxanthin accumulation, and fatty acid composition of Isochrysis galbana. This study classified light intensity into three categories based on the white LED light source: high (HL, 150 μmol·m⁻²·s⁻¹), medium (ML, 80 μmol·m⁻²·s⁻¹), and low (LL, 30 μmol·m⁻²·s⁻¹). The results showed that biomass concentration was optimized under high light intensity (HL, 150 μmol·m⁻²·s⁻¹), whereas low light (LL, 30 μmol·m⁻²·s⁻¹) yielded the highest fucoxanthin concentration (71.15 mg/L on day 12) and the only positive volumetric fucoxanthin productivity (3.14 mg/L/d) among the three treatments tested. The results further showed that low light (LL, 30 μmol·m⁻²·s⁻¹) produced maximum cell density (10.08 × 10⁶ cells/mL) and the most polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which constituted 1.93% and 22.47% of total fatty acids, respectively. This study demonstrates that low-intensity (LL, 30 μmol·m⁻²·s⁻¹) white LED light supports the maximum co-production of valuable metabolites in I. galbana, establishing a scientific basis for scaling up I. galbana cultivation for nutraceutical and aquafeed applications. Full article

Background/Objectives: Metabolic dormancy in biofilms leads to reduced drug efficacy in these communities. Different pharmacokinetics and adverse side effects complicate the simultaneous delivery of multiple drugs at appropriate concentrations to the infection site. This study aimed to develop chitosan-coated mesoporous silica nanoparticles loaded with curcumin and amphotericin B (CS@MSNs-Cur-AmB) and to evaluate their antibiofilm activity combined with antimicrobial photodynamic therapy (PDT) against Streptococcus mutans and Candida albicans dual-species biofilms. Methods: CS@MSNs-Cur-AmB were developed. The structure and morphology of the nanoparticles were evaluated using Fourier transform-infrared spectroscopy (FTIR), zeta potential, field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). Cytotoxicity toward human gingival fibroblasts was assessed. Colony-forming units per milliliter (CFU/mL) were determined. The metabolic activity of biofilm-forming cells was measured using the tetrazolium (MTT) assay. Results: Physicochemical analyses confirmed the synthesis of CS@MSNs-Cur-AmB, revealing a particle size of 228 nm and thermal stability up to 600 °C. Cytotoxicity assays showed that CS@MSNs-Cur-AmB exhibited good biocompatibility (>90%). CS@MSNs-Cur-AmB improved antimicrobial activity, which was further enhanced by blue light-emitting diode (LED) irradiation. CS@MSNs-Cur-AmB under LED irradiation showed the strongest effect, reducing metabolic activity to 27.74 ± 4.08% (1 W/cm², 1 min), p < 0.001). Conclusions: Formulating two drugs in nanocarrier systems may improve therapeutic efficacy by increasing local concentration and reducing systemic exposure. This offers an effective strategy for combating oral biofilms. Full article

AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) have been widely deployed in water treatment, sterilization, and optical communication owing to their intrinsic merits of mercury-free operation, compact footprint, and fast turn-on capability. However, poor reliability and short operating lifetime, mainly caused by electrical degradation and poor heat dissipation, have severely limited their commercial applications. In this work, the degradation mechanism of 270 nm DUV LEDs was systematically studied via multi-condition accelerated aging tests. Results confirm that electrical stress is the dominant factor inducing device degradation, while thermal stress plays a secondary role. Electrical stress generates internal defects, increases leakage current and thermal resistance, enhances non-radiative recombination, and causes a sharp drop in light output power. Based on test data, the L70 lifetimes predicted by the inverse power law and the Arrhenius models are 5832 h and 5724 h, with relative errors of 8.59% and 10.28% compared with the measured 6380 h. This work provides reliable experimental support for the performance evaluation and lifetime prediction of DUV LEDs. Full article

When driving a partially automated vehicle, maintaining situation awareness is essential for users to be better prepared to take over. A primary challenge is maintaining awareness while the user is occupied with another task without tunneling attention towards individual elements. To investigate this, we conducted an experimental study in our driving simulator (n = 20) comparing an indirect LED (light-emitting diode) visualization of relevant objects in the driver’s field of view with a combined condition of an indirect LED + direct HUD (head-up display) visualization. The participants’ situation awareness scores were higher under the combined condition. However, the scores dropped significantly for objects outside the LED + HUD visualization. We conclude that the indirect object indication is not effective in countering tunneling effects from the HUD, and neither does it provide a satisfactory trade-off when deployed on its own, i.e., without direct indication in addition. Full article

Organic–inorganic hybrid halide perovskites have attracted extensive attention due to their excellent optoelectronic properties and potential applications in field-effect transistors (FET), light-emitting diodes (LEDs), and photodetectors. However, conventional three-dimensional (3D) perovskites are limited by intrinsic instability and ion migration. Two-dimensional Ruddlesden-Popper (2D RP) perovskites offer improved structural stability, but many systems still suffer from modest photoluminescence efficiency and limited charge-transport performance. In this work, a novel 2D RP perovskite, (C₆H₅NH₃)₂CsPb₂Cl₇, was designed and synthesized, where the anilinium ion (C₆H₅NH₃⁺) serves as the organic spacer. Structural characterization indicates that the material possesses high crystallinity and a smooth surface morphology. Optical measurements reveal a violet emission peak at 411 nm with a single-peak feature and a full width at half maximum (FWHM) of 10 nm. The bandgap is determined to be 3.1 eV. Time-resolved photoluminescence (TRPL) measurements show an average lifetime of 4 ns, and the photoluminescence quantum yield (PLQY) is 29.8%. Based on the measured PLQY and lifetime, the radiative and non-radiative recombination rates were estimated to be K_r ≈ 7.45 × 10⁷ s⁻¹ and K_nr ≈ 1.76 × 10⁸ s⁻¹, respectively, suggesting that radiative recombination is appreciable although non-radiative pathways remain present. FET measurements demonstrate an on/off current ratio of 10⁴ and a carrier mobility of 1.1 cm² V⁻¹ s⁻¹. Without any systematic optimization, (C₆H₅NH₃)₂CsPb₂Cl₇ exhibits relatively favorable emissive behavior and measurable field-effect charge transport performance when compared with structurally similar 2D RP perovskites reported under comparable, non-optimized conditions. This study expands the family of chloride-based 2D perovskites and provides a basis for future improvements in their recombination and field-effect transport properties. Full article

Light combined with refrigeration is an effective strategy for preserving postharvest fruit and vegetable quality. This study explored the effects of various red–blue (R/B) light-emitting diode (LED) light/dark (L/D) cycles on pak choi during refrigeration. Pak choi exposed to a 4/20 h L/D cycle exhibited greater freshness, along with the highest levels of total phenolic compounds, chlorophyll, and ascorbic acid, particularly after 6 days of refrigeration. Transcriptomic analysis showed that this lighting regime upregulated genes associated with phenylpropanoid and flavonoid biosynthesis (PAL, C4H, ANS, CHS, FLS) and ascorbate metabolism (VTC2_5, VTC4, APX), boosting phenolic and ascorbic acid content. It also reduced chlorophyll degradation by increasing the expression of genes in the porphyrin metabolism pathway (CRD1, POR, DVR). These findings highlight the benefits of R/B light with a 4/20 h L/D cycle for enhancing pak choi quality during refrigeration storage. This approach provides an efficient approach for vegetable preservation. Full article

The growing problem of antibiotic resistance poses a serious threat to public health and ecosystems. New disinfection methods could help address this global issue. In this study, ultraviolet-C light-emitting diodes (UV-C LEDs) were used to inactivate Escherichia coli isolates resistant to antibiotics. These isolates were obtained from various real water sources, including seawater, surface water, and treated wastewater. Inactivation assays were performed using two wavelengths (255 nm and 265 nm), applying UV fluences ranging from 1 to 7 mJ/cm² to a phosphate-buffered saline solution inoculated with a mixture of 10 E. coli strains. Using an UV fluence of 2 mJ/cm², a log reduction of about 5 was achieved with both UV-C wavelengths tested. SEM imaging revealed no observable alterations in cell morphology after UV-C exposure. Pyrimidine dimer formation was quantified, yielding approximately 40 ng/mL of cyclobutane pyrimidine dimers after 2 mJ/cm² of exposure to both wavelengths. Additionally, water treatment was tested using ceramic silicon carbide membranes. High average rejection efficiencies (99.9%) were obtained for both total coliforms and E. coli using uncut flat sheet membranes. The combination with UV-C LEDs led to treatment of the concentrated membrane retentate (99.985% or higher), highlighting the potential of this treatment approach for effective water disinfection. Full article

Echeveria spp. (Mexican hens and chicks) are among the most popular genera of succulents sold because they are compact and form attractive, symmetrical rosettes with brightly colored, fleshy, broad, iridescent leaves, as well as large, showy inflorescences. However, they are slow-growing, and flower induction protocols are not widely available. Therefore, the objectives of this study were (1) to determine if photoperiod and the photosynthetic daily light integral (DLI) can be manipulated to promote rapid growth and leaf expansion without excessive extension growth of several cultivars of Echeveria and (2) to establish the critical photoperiod for flower induction. Cuttings of E. spp. and hybrids ‘Apus’, ‘Canadian’, ‘Elegans Blue’, ‘Jade Point’, and ‘Topsy Turvy’ were received from a commercial breeder and grown in a greenhouse at 20 °C for 5 weeks. Photoperiods were created using a truncated 9 h short day (SD) or a SD extended to 10, 11, 13, 15, 16 h or a 4 h night-interruption (NI), using light-emitting diode (LED) lamps providing a total photon flux density of ≈2 μmol·m⁻²·s⁻¹ of red (R) + white (W) + far-red (FR) radiation. DLIs of 4.8 and 12.8 mol·m⁻²·d⁻¹ were maintained with and without shade cloth and supplemental lighting. Photoperiod and DLI interacted to influence the final height of E. ‘Canadian’, ‘Elegans Blue’, and ‘Jade Point’; plants were tallest under photoperiods > 13 h and low DLI. Similar trends were observed for growth index and average plant diameter. No clear trend was observed for leaf unfolding or leaf length across DLI or photoperiod treatments. Flower initiation of E. ‘Apus’ and ‘Jade Point’ was highest under a DLI of 12.8 mol·m⁻²·d⁻¹. Additionally, E. ‘Jade Point’ only developed inflorescences under day lengths ≤ 11 h, indicating an obligate SD response. Our results suggest that growers should maintain DLIs > 10 mol·m⁻²·d⁻¹ and SD conditions to promote flower initiation of the Echeveria cultivars tested. Such conditions would prevent excessive stem elongation and encourage flowering, increasing crop quality and marketability. Full article

Visible light communication (VLC) employs light-emitting diodes (LEDs) for simultaneous illumination and wireless data transmission, offering advantages such as unlicensed spectrum, immunity to electromagnetic interference, and intrinsic security. Conventional PAM-VLC transmitters generally rely on a single high-power LED driven by analog front-end components, such as digital-to-analog converters and power amplifiers, which increase hardware complexity, power consumption, and thermal burden. To address these limitations, this paper proposes an energy-efficient spatial-combining VLC transmitter in which multiple LEDs are directly driven by FPGA GPIO ports, without using DACs or power amplifiers. Multilevel PAM is digitally realized by controlling the number of activated LEDs, and the emitted optical signals are spatially combined through an optical lens. Experimental results demonstrate reliable 1 m free-space transmission. At a bit-error rate (BER) of 3.8 × 10⁻³, the proposed scheme achieves SNR gains of 0.75 dB for PAM-4 and 0.8 dB for PAM-8 over the conventional pulse amplitude modulation (PAM)-VLC architecture. Moreover, the proposed transmitter reduces power consumption by 38.7%. These results confirm that digitally driven multi-LED spatial combining is a promising solution for low-cost and energy-efficient VLC systems. Full article

Autonomous driving in underground mines faces significant challenges due to Global Navigation Satellite System (GNSS) denial and harsh environmental conditions. Mainstream multi-sensor fusion and Simultaneous Localization and Mapping (SLAM) schemes have achieved substantial progress in underground navigation, but their deployment in feature-sparse tunnels may still face challenges related to computational burden and perception robustness. This study explores an infrastructure-assisted navigation architecture that transforms the roadway into a structured luminous guidance channel by deploying programmable Light Emitting Diode (LED) strips along the tunnel roof. The proposed system simplifies complex three-dimensional pose estimation into a two-dimensional visual servoing task targeting optical signals. Central to this approach is a robust data fusion strategy that utilizes a topology matching algorithm to map noisy Ultra-Wide-band (UWB) coordinates onto a discrete LED index space, thereby providing a reliable global positioning reference. Furthermore, a hierarchical fault-tolerant controller based on a Finite State Machine (FSM) is designed to facilitate seamless degradation to a UWB-assisted ultrasonic wall-following mode in the event of visual degradation, supporting fault-tolerant operation under controlled laboratory conditions. Experimental results in a laboratory simulation environment demonstrate that the system achieves millimeter-level static initialization accuracy, a dynamic tracking Root Mean Square Error of approximately 4 cm, and a 100% autonomous recovery rate from visual failures in straight tunnels. These results demonstrate the feasibility of the proposed infrastructure-assisted route under controlled laboratory conditions and suggest its potential as an engineering reference for structured underground transport scenarios with acceptable infrastructure modification. Full article