Light-emitting Diode Light Research Articles

Evaluating Organic Fertilizers and Microbial Inoculation for Soilless and Hydroponic Crop Production

Because hydroponic operations in the United States can be certified as organic, and because the price of chemical fertilizers has increased, there is an increasing interest in using organic fertilizers and beneficial microorganisms for controlled-environment agriculture. However, there is a scarcity of information regarding their effectiveness and application methodologies. We investigated the effects of inoculating Azospirillum brasilense and Rhizophagus intraradices and using organic fertilizers on growing lettuce (Lactuca sativa ‘Cherokee’) and tomato (Solanum lycopersicum ‘Red Robin’) young plants in an indoor vertical farm. Seeds were sown in rockwool substrate, with A. brasilense (1.05 × 108 colony-forming units⋅L−1) or R. intraradices (580 propagules⋅L−1) applied weekly via subirrigation. Seedlings received chemical fertilizer, organic fertilizer derived from corn steep liquor and fermented fish by-products, and food waste-derived organic fertilizer at 100 ppm total nitrogen every 2 or 3 days. They were grown indoors at 23 °C under light-emitting diode lighting at a photosynthetic photon flux density of 200 μmol⋅m−2⋅s−1 with an 18-hour photoperiod. Lettuce under organic fertilizers had 75% lower shoot fresh mass and 64% less shoot dry mass compared with lettuce under chemical fertilizer. Similarly, tomato seedlings with organic fertilizers had fewer leaves, 75% less shoot fresh mass, and 67% less shoot dry mass. In both lettuce and tomato, the macronutrient and micronutrient concentrations in plant tissues were generally similar regardless of fertilizer treatments, but nitrogen use efficiency and nitrogen uptake efficiency were lower under organic fertilizers compared with those under chemical fertilizer. The inoculation of A. brasilense or R. intraradices showed limited effects on plant nutrient uptake, nutrient concentrations, and seedling growth in both lettuce and tomato. Further research is necessary to optimize application methods for organic fertilizers and beneficial microorganisms to fully harness the benefits of sustainable alternative fertilizers in soilless and hydroponic crop production.

Simulating PDT of port-wine stains in the in vivo chicken wattle model using Hemoporfin and radiation at 532 nm: Comparison of a LED and a laser source

Port-wine stain (PWS) birthmarks are congenital capillary malformations occurring in 0.3 %∼0.5 % of newborns. Hemoporfin-mediated vascular-acting photodynamic therapy (Hemoporfin PDT) is an emerging option for treating PWS. This in vivo study aimed to compare laser and light-emitting diodes (LED) as light source for Hemoporfin PDT. Chicken wattles were used as the animal model. Color and histopathological changes were evaluated after combining Hemoporfin with KTP laser or LED light source of 532 nm at the same doses. Both PDT approaches could induce significant vascular injury and color bleaching. Although the use of the laser resulted in a greater vascular clearance, the LED showed more uniform distribution both in the beam profiles and tissue reaction and exhibited better safety. This in vivo study suggests that the LED is a favorable choice for larger PWS lesion.

The Effect of Light-emitting Diode Light Intensities and Duration of Cure on Pulpal Wall Temperature among Different Classes of Teeth.

The thermal changes during light curing of resin-based composites (RBCs) are recognized, but there is a lack of information about temperature changes in pulp tissue under different curing protocols, especially during bonding of orthodontic brackets onto the tooth surface. In the present study, pulpal temperature (PT) variation induced by the use of four different light cure intensities and different durations of cure among different classes of teeth was measured. A total of 80 different classes of human extracted teeth (maxillary and mandibular central incisor, lateral incisor, canine, premolar, and molar) were irradiated at the same distances with four visible light curing intensities. Brackets (3M Unitek) were bonded with Transbond XT (3M Unitek, Monrovia, California) adhesive and light cured with a light-emitting diode (LED) light cure unit (LCU) (Bluephase). A J-type thermocouple wire was positioned in the center of the pulp chamber to assess the temperature difference. The results were analyzed with analysis of variance (ANOVA) and the Tukey's honestly significant difference (HSD) test. Light-emitting diode with higher intensity induced significantly higher intra-PT changes than did the LED with lower intensity (p < 0.001). Mandibular central incisors had the highest intra-PT of about 45°C at 3000 mW/cm2, 3 seconds. Maxillary central incisors had the highest intra-PT of about 40°C at 3000 mW/cm2, 3 seconds. Mandibular and maxillary canines and molars had the lowest intra-PT of about 10°C at 800 mW/cm2, 20 seconds. Pulp chamber temperature changes were influenced by the intensity and duration of curing and the anatomy of the tooth (class/type of tooth). S S, Anbarasu P, S SK, et al. The Effect of Light-emitting Diode Light Intensities and Duration of Cure on Pulpal Wall Temperature among Different Classes of Teeth. Int J Clin Pediatr Dent 2024;17(4):467-471.

Guild‐specific response of bats to motion‐triggered LED lighting of bicycle trails

AbstractMotion‐triggered light‐emitting diodes (LED) could reduce light pollution; however, its effect on nocturnal animals is poorly known. Here, we investigated how bats respond to the motion‐triggered lighting of a bicycle path, an infrastructure that is increasingly being built to support human mobility. We measured the acoustic activity of bats in relation to the activity of LED lights. The responses of bats varied during the night and between functional guilds: Edge‐space foraging bats avoided LED lighting, but the response was less clear during early and late night. Open‐space foraging and narrow‐space foraging bats avoided the LED lighting, especially late at night. The foraging intensity remained relatively stable across the night for bats of all guilds. We conclude that the motion‐sensitive LED lighting of bicycle paths induces a guild‐specific avoidance response in bats, which could be mitigated by shorter lighting periods.

Impacts of Emergency Vehicle Marking Characteristics and Wearable Lights on Driver Responses

Retroreflective markings provide important visual information to drivers about emergency vehicles and the incidents at which they are working. A stationary outdoor field study to investigate the impacts of emergency vehicle marking color, retroreflectivity level, and spatial patterns on drivers’ ability to see nearby emergency responders was carried out. The study also examined the impacts of a wearable flashing light-emitting diode (LED) light. Based on the results, agencies should use materials with higher levels of retroreflectivity carefully, especially when they will be covering large-area vehicle surfaces. Limiting the maximum retroreflectivity level to no greater than American Society for Testing and Materials Type III may help lessen negative impacts of bright reflective materials on drivers’ ability to see emergency responders. As long as the average reflectivity of different color combinations is similar to that of red and yellow reflective markings, chevron patterns with those color combinations will not reduce emergency responder visibility. Outline patterns of reflective markings on vehicles performed similarly at night to patterns covering most of the vehicle surface. The effectiveness of using high-retroreflectivity materials in an outline pattern in combination with lower- (or non-) retroreflectivity materials elsewhere on the surface should be studied. Wearable flashing LED lights can make emergency responders easier to see at night, provided they do not increase glare to approaching drivers.

The effect of combined red, blue, and near-infrared light-emitting diode (LED) photobiomodulation therapy on speed of wound healing after superficial ablative fractional resurfacing

Objective of the study is to assess the effects of wound healing with a commercially available light emitting diode (LED) photo biomodulation (PBM) device that emits three wavelengths (465, 640 and 880nm) after ablative fractional laser (AFL) treatment to healthy skin on the bilateral inner biceps. We conducted a prospective intraindividual randomized controlled study with 25 volunteers. AFL treatment was performed on healthy skin of the bilateral inner biceps. Subjects applied the LED light device for 30 min to the assigned bicep 3 times a week over 4 weeks, beginning on day 0. Subjects were followed up on days 2, 4, 6, 9, 13, 20 and 27 for treatment with the PBM device, clinical digital photography of the test and control sites, and in-person subject assessment, with follow ups on days 34 and 55 for clinical photography and assessment. Three blinded evaluators were asked to determine which bicep healed faster between day 0 to day 13. Pain, discomfort, and itch were also assessed. The three blinded evaluators chose the treatment arm as the faster healed arm in greater than 50% of the images, although the results were not statistically significant. There was no statistically significant difference between test and control arms in terms of pain, discomfort and itch. In conclusion, PBM therapy has the potential to improve wound healing. In this study, a three wavelength PBM device resulted in some subjects achieving faster healing after AFL but the results were not statistically significant.

Life cycle assessment of high-power white LEDs for indoor lighting in the context of Hong Kong

The introduction of white light-emitting diodes (LEDs) is one of the key innovations that has revolutionized the lighting industry due to its multiple benefits. Despite their advantages, there is a gap in the environmental impact information of the recently developed high-power LED products within the whole lifecycle, which is a key step to achieve sustainable and green development. This life cycle assessment (LCA) is conducted by considering the cradle-to-grave system boundary. The functional units considered are a LED and compact fluorescent lamp (CFL) of 40 million lumen-hours (lm-h) used for indoor applications over an operating time of 20 000 h. In this study, the LCA was carried out using the SimaPro software and built-in ecoinvent database V2.2 with appropriate life cycle inventory data. The analysis results indicate that: (1) the LED-package has a dominant environmental impact followed by the LED driver while the housing and corrugated-board packaging materials showed the least negative effect to the ecosystem during the manufacturing phase. On the contrary, the CFL drivers are dominant followed by the light sources in the case of CFLs. From the lifecycle stages, the usage-phase showed a predominant environmental effect, mainly due to the energy consumption and sources of energy production. (2) A scenario analysis on the sources of electricity production revealed that prospective sources (70% natural gas, 25% nuclear and 5% pumped storage) of energy production lowered the environmental impact compared to the current electricity mix. These proposed electricity generation production sources provide a 61% reduction in the global warming potential in light sources for Hong Kong.

Artificial intelligence models for validating and predicting the impact of chemical priming of hydrogen peroxide (H2O2) and light emitting diodes on in vitro grown industrial hemp (Cannabis sativa L.).

Industrial hemp (Cannabis sativa L.) is a highly recalcitrant plant under in vitro conditions that can be overcome by employing external stimuli. Hemp seeds were primed with 2.0-3.0% hydrogen peroxide (H2O2) followed by culture under different Light Emitting Diodes (LEDs) sources. Priming seeds with 2.0% yielded relatively high germination rate, growth, and other biochemical and enzymatic activities. The LED lights exerted a variable impact on Cannabis germination and enzymatic activities. Similarly, variable responses were observed for H2O2 × Blue-LEDs combination. The results were also analyzed by multiple regression analysis, followed by an investigation of the impact of both factors by Pareto chart and normal plots. The results were optimized by contour and surface plots for all parameters. Response surface optimizer optimized 2.0% H2O2 × 918 LUX LEDs for maximum scores of all output parameters. The results were predicted by employing Multilayer Perceptron (MLP), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost) algorithms. Moreover, the validity of these models was assessed by using six different performance metrics. MLP performed better than RF and XGBoost models, considering all six-performance metrics. Despite the differences in scores, the performance indicators for all examined models were quite close to each other. It can easily be concluded that all three models are capable of predicting and validating data for cannabis seeds primed with H2O2 and grown under different LED lights.

High β-carotene accumulation in transgenic eggplant fruits grown under artificial light.

Eggplant (Solanum melongena L.) fruits are known to contain few carotenoids such as β-carotene, which are abundant in congener tomato fruits. In a previous study, we introduced a fruit-specific EEF48 gene promoter-driven crtB gene encoding phytoene synthase (PSY) of Erwinia uredovora into eggplant 'Senryo No. 2'. The transgenic plants grown in a greenhouse set fruits that accumulated β-carotene (∼1.67 µg g-1FW) in the T0 and T1 generations. In the present study, we grew T1 and T2 generations of the transgenic eggplant plants in artificial climate chambers to investigate their fruit set and β-carotene accumulation. No clear difference in β-carotene accumulation was observed in the fruit of transgenic plants grown under either HID (high-intensity discharge) or LED (light-emitting diode) light, or between T1 and T2 generations. The β-carotene accumulation (8.83 µg g-1FW on average) was approximately 5 times higher than the previous results obtained from greenhouse-grown plants. However, the fruit weight and size of the T-DNA (+) plants were significantly smaller than that of their null-segregant T-DNA (-) plants derived from the same line, suggesting that β-carotene accumulation may inhibit fruit development. Considering that a part of plants grown under LED irradiation failed to set fruits or set smaller fruits than those grown under HID irradiation, the light condition in the LED chamber may not be sufficient to promote fruit development. The present results are expected to provide valuable information for the selection of transgenic eggplants with high β-carotene content in fruit under artificial lighting.

Dual-channel on-chip data transmission system using UV light based on GaN-on-Si wafer

The ultraviolet photonic integrated circuits possess application prospects in ultraviolet (UV) microscopy, bio-sensing, on-chip data communication, etc. Herein, we propose a UV light on-chip data transmission system based on epitaxial GaN on silicon. This simple system includes a light-emitting diode light source, a modulator, a Y-branch waveguide and two photodetectors. Both direct modulation and indirect modulation are configured into this system and demonstrated by experiment. Dual-channel communication is also implemented through Y-branch waveguide. As all the active devices share the same InGaN/AlGaN multiple quantum wells (MQW) diode structure, this 378 nm UV light data transmission system can be monolithically integrated through the compatible manufacturing processes. By adopting the integrated MQW modulator with relatively large active region area, a significant modulation effect can be achieved with modulation depth greater than 48% under reverse bias of 20 V.

Leading Light: The Impact of Advanced Lighting Technologies on Indonesia's Office Industry

Addressing concerns over resource scarcity and environmental sustainability necessitates a global shift towards sustainable energy, notably facilitated by adopting Light-Emitting Diode (LED) lamps. This transition is pivotal for ensuring global energy security and aligning with sustainability goals. This study endeavors to comprehensively analyze potential energy savings achievable through the transition from Fluorescent (FL) lamps to LED lamps within industrial offices. Emphasis is placed on highlighting the central role of energy efficiency. Utilizing false color rendering as a visual guide, the study systematically identifies areas where FL lamps inadequately illuminate. The findings prompt recalculations for determining optimal room illumination achievable through implementing LED lamps. Lux calculations are then employed to showcase the superior illumination offered by LED lamps, revealing consistent monthly cost savings of 35%, particularly when harmonized with Building Management System (BMS) control in industrial office buildings. The study's results indicate that LED lamps provide superior illumination, yielding a noteworthy 35% monthly cost savings, especially when integrated with BMS control. Lamps contribute modestly (21-30%) to overall energy consumption, while air conditioning commands a substantial 60%, underscoring the critical need for advanced lighting technology. This need is emphasized, particularly with Solar PV as a sustainable energy source. Understanding technological developments, especially in BMS, is crucial to optimize energy efficiency in industrial offices. The imperative implementation of LED lighting technology is a critical solution to address resource scarcity and environmental concerns in industrial offices. The efficacy of LED lamps in achieving significant energy savings, especially when coupled with advanced systems like BMS and complemented by renewable energy sources such as Solar PV. The conclusion stresses the significance of staying abreast of technological advancements to foster sustained progress towards energy-efficient and environmentally conscious practices within industrial environments.

Microleakage of two resin composites by using different light curing systems

This study was conducted to evaluate marginal microleakage of two resineomposite (Glacier resin composite and Filtek P 60 resin composite) either cured witheonventional light cure unit ( Astralis 5) or light emitting diodes (LED) light cure unit»Radii). Forty class V cavities were prepared in 20 extracted second premolars, onebuccaly and one palataly in each tooth. Each cavity was located lmm coronal toeementoenamel junction and lmm apical to it. The teeth were randomly divided into 4groups, each group of five teeth (I0 cavities): Group I was filled with Glacier resincomposite and cured with LED curing unit. Group ll filled with Glacier and curedin ith Astralis 5 curing unit. Group lll filled with Filtek P60 resin composite and curedv- ith LED curing unit. Group IV filled with Filtek P 60 and cured with Astralis curingxnit. The teeth were stored in distilled water for seven days. Then the apices of theteeth were sealed with sticky wax and the teeth were covered with two layers of nailvamish except lmm around the restoration. The teeth were immersed in 0.5% basicfaehsin dye for 24 hours at 37°C in the incubator and then were longitudinallyxctioned in a buccolingual direction and the extent of dye penetration was recorded.The statistical analysis of the result revealed that the use of LED light cure unit,results in highly significant reduction in the microleakage occlusally and gingivally

Growth, leaf anatomy, and photosynthesis of cotton (Gossypium hirsutum L.) seedlings in response to four light-emitting diodes and high pressure sodium lamp

BackgroundLight is a critical factor in plant growth and development, particularly in controlled environments. Light-emitting diodes (LEDs) have become a reliable alternative to conventional high pressure sodium (HSP) lamps because they are more efficient and versatile in light sources. In contrast to well-known specialized LED light spectra for vegetables, the appropriate LED lights for crops such as cotton remain unknown.ResultsIn this growth chamber study, we selected and compared four LED lights with varying percentages (26.44%–68.68%) of red light (R, 600–700 nm), combined with other lights, for their effects on growth, leaf anatomy, and photosynthesis of cotton seedlings, using HSP lamp as a control. The total photosynthetic photon flux density (PPFD) was (215 ± 2) μmol·m−2·s−1 for all LEDs and HSP lamp. The results showed significant differences in all tested parameters among lights, and the percentage of far red (FR, 701–780 nm) within the range of 3.03%–11.86% was positively correlated with plant growth (characterized by leaf number and area, plant height, stem diameter, and total biomass), palisade layer thickness, photosynthesis rate (Pn), and stomatal conductance (Gs). The ratio of R/FR (4.445–11.497) negatively influenced the growth of cotton seedlings, and blue light (B) suppressed stem elongation but increased palisade cell length, chlorophyll content, and Pn.ConclusionThe LED 2 was superior to other LED lights and HSP lamp. It had the highest ratio of FR within the total PPFD (11.86%) and the lowest ratio of R/FR (4.445). LED 2 may therefore be used to replace HPS lamp under controlled environments for the study of cotton at the seedling stage.

Combined effect of LED light color and nitrogen source on growth, pigments composition and oxidative stress in Arthrospira platensis

Artificial lighting with light-emitting diodes (LED) is proposed as a suitable solution to reach stable yearly production of high value molecules from microalgae under unfavorable climates. However, available studies are inconsistent regarding the effect of LED color on cultures performance. This study examined the response of Arthrospira platensis to three different LED lighting conditions (white, red, and red-blue 70:30) when is grown in three media with different nitrogen composition. Growth, phycobiliproteins and lipophilic pigments content were determined. In addition, antioxidant enzymes (GST, lipid peroxidation) and morphology were analyzed to enlighten new perspectives on the health status of microalgae production.The highest biomass production (2.13 g/L) was achieved under red LED when Zarrouk medium was supplemented with urea. Regarding pigment production (phycobilins, chlorophyll a and β- carotene), the most desirable combination was red: blue together with urea supplementation. In addition, this combination showed a high biomass production (2.03 g/L) and low expression of antioxidant enzymatic activity. This research shows a novel combination of LED technology and nutrients to enhance microalgae biomass production and high value metabolites with a lower economic cost.

Smart Hydroponic Farming System Integrated with LED Grow Lights

Vertical farming, including hydroponics, is a growing trend in the agricultural sector due to the increasing demand for food and urbanisation. Thus, hydroponics can save space and achieve faster plant growth compared to traditional farming methods. The concept of smart farming has been applied in this study to improve the ease of control and monitoring of hydroponic systems. The effects of light-emitting diodes (LEDs), light distance, and colour (purple and white) on water spinach growth in a hydroponic system were investigated. Additionally, an Internet of Things (IoT) controller was developed and implemented to facilitate the use of the system in an indoor hydroponic-based environment system. Based on the results, the distance between the LED light of 15 cm and the plants and the colour of the LED light (white) can positively impact plant growth in a hydroponic system. Using an IoT controller also allows for continuous monitoring and control of factors that influence plant growth. Hence, this research would catalyse the local smart hydroponic farming system for improved deliverables.

Nighttime light in China's coastal zone: The type classification approach using SDGSAT-1 Glimmer Imager

Nighttime Light (NTL) is highly concentrated in China's coastal zone, leading to negative health impacts on both humans and wildlife. Particularly, in recent years, the widespread adoption of broad-spectrum Light-Emitting Diode (LED) light, a low-carbon technology providing substantial increases in luminosity, has led to certain ecological consequences. Thus, information regarding spatial distribution and composition of different NTL types is essential for formulating sustainable strategies that balance nighttime public security, energy consumption, and ecosystem conservation. However, the availability of such information remains limited. To address this challenge and meet the demand, we developed two new light indices, namely the Ratio Red Light Index (RRLI) and Ratio Blue Light Index (RBLI), based on SDGSAT-1 Glimmer Imager (GLI) multispectral NTL data. We then proposed a threshold method and applied it to the entire coastal zone of China to identify White LED (WLED), Red LED (RLED), and Other lights (Other). Results showed the following. (1) In the coastal zone of China, the total lighting area was 20,517 km2, including 20,257 km2 of terrestrial lights and 260 km2 of offshore lights; (2) WLED light covered 67% (13,727 km2) of all lighting areas, while RLED lights accounted for only 1% (220 km2); (3) Guangdong had the largest lighting area (5221 km2), with the proportion of WLEDs being the highest among all coastal provinces (almost 90%); (4) The proportions of lighting areas were relatively low in Guangxi, Liaoning, and Hebei. This study represents the first attempt to identify NTL types over large regions at a finer spatial resolution. The approach proposed, including the light indices of RRLI and RBLI, as well as the defined thresholds, is universal and robust for use in NTL type classification. The developed lighting type map, containing comprehensive information on the spatial distribution and composition of NTL, could facilitate the sustainable management of China's coastal zones.

The Growth and Tuber Yield of Potatoes (Solanum tuberosum L.) under Varying LED Light Spectrums in Controlled Greenhouse Conditions

Plant growing using light-emitting diodes (LEDs) in a controlled environment is a revolutionary and innovative idea, regardless of the external environmental disturbances. Studying the growth and tuber yield of potatoes (Solanum tuberosum L.) in an LED-based plant factory system is a relatively innovative concept. The current study was conducted in a plant factory to evaluate the effects of different LED spectral compositions on potato tuberization. Potato tuberization was analyzed under six different LED light spectral combinations with irradiances of 300 mol m−2 s−1, with natural light considered the control treatment. The findings stated that the L2 treatment (red70 + blue20 + white10) increased the plant height, branch number, and biomass accumulation, while photosynthetic pigments and photosynthetic activity increased significantly in L5 (red60 + blue20 + green10 + white10). Higher gibberellic acid (GA3) content was recorded in L1 (red70 + blue30), whereas the tuber number and tuber fresh weight were recorded in L3 (red70 + blue20 + green10) and L7 (natural light), respectively. On the other hand, a higher number of smaller-sized tubers were observed in L5, while L2 and L4 (red70 + blue20 + far-red10) resulted in a higher number of medium-sized tubers. In conclusion, a high proportion of red and blue light, along with white and far-red light, increased the plant height, branch number, plant biomass, and production of small- and medium-sized tubers. On the other hand, the inclusion of green light with red and blue enhanced the chlorophyll content, photosynthesis, and leaf expansion, and promoted the production of smaller-sized tubers. Finally, with regard to tuberization, the treatment using L4 followed by L2 outperformed the other treatments.

Quantum dots boost large-view NIR-II imaging with high fidelity for fluorescence-guided tumor surgery

Owing to the high spatiotemporal resolution, the second near-infrared (NIR-II) imaging window can provide high imaging contrast with diminished tissue autofluorescence and suppressed photon scattering to pinpoint the locations for tumor surgery. Due to the unique optical properties and excellent fluorescence performance, quantum dots (QDs) are regarded as ideal nanoprobes for fluorescence-guided surgery (FGS). Moreover, QDs can be excited by a variety of light sources owing to the continuous and wide absorption ranges. Herein, light-emitting diode (LED) was used as the excitation source of QDs-based nanoprobes to realize FGS of tumor with high resolution. Since the LED light could irradiate a large region with consistent light intensity, signal distortion at the edge of imaging field was avoided. The signal intensity of the view edges under LED excitation can be improved by about 5 times compared to laser excitation. Therefore, more micro-vessels and smaller tumors (Vtumor < 5 mm2) could be detected, thus providing more precise guidance for tumor resection surgery.

Satellite Hyperspectral Nighttime Light Observation and Identification with DESIS

The satellite imagery of nighttime lights (NTLs) has been studied to understand human activities, economic development, and more recently, the ecological impact of brighter night skies. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day–Night Band (DNB) offers perhaps the most advanced nighttime imaging capabilities to date, but its large pixel size and single band capture large-scale changes in NTL while missing granular but important details, such as lighting type and brightness. To better understand individual NTL sources in a region, the spectra of nighttime lights captured by the DLR Earth Sensing Imaging Spectrometer (DESIS) were extracted and compared against near-coincident VIIRS DNB imagery. The analysis shows that DESIS’s finer spatial and spectral resolutions can detect individual NTL locations and types beyond what is possible with the DNB. Extracted night light spectra, validated against ground truth measurements, demonstrate DESIS’s ability to accurately detect and identify narrow-band atomic emission lines that characterize the spectra of high-intensity discharge (HID) light sources and the broader spectral features associated with different light-emitting diode (LED) lights. These results suggest the possible application of using hyperspectral data from moderate-resolution sensors to identify lamp construction details, such as illumination source type and light quality in low-light contexts. NTL data from DESIS and other hyperspectral sensors may improve the scientific understanding of light pollution, lighting quality, and energy efficiency by identifying, evaluating, and mapping individual and small groups of light sources.

(276) Light Emitting Diodes (LED) as a Potential Therapy for Erectile Function: A Preclinical Study in a Cavernous Nerve Injury Model

Abstract Introduction Erectile dysfunction (ED) induced by nerve injury including prostatectomy poorly responds to PDE5 inhibitor and requires invasive treatment. Light emitting diodes (LED) in some spectral range, is able to irradiate cells without overheating for its low energy consumption and to enhance mitochondrial metabolism, intracellular energy transfer, and thereby cell proliferation and tissue regeneration in some organs. We, herein, investigated whether and how LED therapy may improve penile erection in mouse cavernous nerve injury (CNI) - induced ED model Objective To identify the optimal LED parameters using molecular, histological, and erectile function analysis in cavernous nerve injury. Methods Eight week old male mice (n=120) were divided into 5 age-matched groups, a sham operation group receiving heat treatment, a CNI group receiving heat treatment, a CNI group receiving red light of LED (wavelength; 660 ±3% nm), a CNI group receiving near infrared light of LED (wavelength; 830 ±2% nm), and a CNI group receiving combination of both LED light. Mice were exposed to LED light for 30 minutes on the ventral side including penis for 5 consecutive days after CNI operation. Molecular study, histopathological analysis of the penis and erectile function test were done 2 weeks following the treatment in each subject. Results CNI group with heat treatment had much lower maximum and total ICP than sham control group. In contrast, three groups with LED light irradiation exhibited considerably improved maximum and total ICP, and the group with both LED treatments had the best erectile performance, reaching 90% of the sham surgery group. Histologically, mice treated with RED, NIR, or LED irradiation had more cavernous pericytes and endothelial cells than CNI mice after sham operation. In addition, all three CNI groups with various LED lengths improved neuroprotection and brain regeneration in CNI mice. All groups treated with LED showed increased expression of βIII-tubulin, neurofilament-1, and nNOS in cavernous tissue and dorsal nerve bundle. Additionally, LED treatment in three groups, particularly the combination group, significantly increased βIII-tubulin, S100, and myelin basic protein levels, indicating axonal integrity or expansion in the dorsal root and major pelvic ganglions. Molecular analysis of downstream signals of neural regeneration or angiogenesis showed that 3 groups with LED treatment increased phosphorylated PI3K, neurotrophic factors like BDNF, NGF, and NT-3, and angiogenic factors like angiopoietin1 and vascular endothelial growth factor in cavernous tissue and llpopolysaccharide-treated PC-12 cells. The TUNEL assay and BrdU staining of these tissue and cells showed lower cell apotosis and proliferation in LED-treated groups. Conclusions The results show that LED therapy with RED, NIR, preferably combination of each wavelength improves penile erection by neural progection or regeneration in cavernous nerve injury induced-ED. This noninvasive therapy may be useful in near future for ED refractory to PDE5 inhibitor. As far as we are aware, this is the first research to demonstrate the advantage of LED therapy, low level in sexual dyfunction field. Disclosure No.