Journal articles: 'Blue LED light'

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Son, Younghyun, Seok-Jun Yang, Chang Jin Kim, Gyeong Sun Lee, Su Mi Choi, Young Guk Yu, Sang-Young Oh, Mi-Sun Jung, A.-Ra Jo, and Eun Jung Choi. "Performance Optimization of Blue-light Blocking Lens Through Analysis of Blue Light Emitted from LED Light Sources." Journal of Korean Ophthalmic Optics Society 21, no. 4 (December 30, 2016): 393–400. http://dx.doi.org/10.14479/jkoos.2016.21.4.393.

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Johkan, Masahumi, Kazuhiro Shoji, Fumiyuki Goto, Shin-nosuke Hashida, and Toshihiro Yoshihara. "Blue Light-emitting Diode Light Irradiation of Seedlings Improves Seedling Quality and Growth after Transplanting in Red Leaf Lettuce." HortScience 45, no. 12 (December 2010): 1809–14. http://dx.doi.org/10.21273/hortsci.45.12.1809.

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In this study, we determined the effects of raising seedlings with different light spectra such as with blue, red, and blue + red light-emitting diode (LED) lights on seedling quality and yield of red leaf lettuce plants. The light treatments we used were applied for a period of 1 week and consisted of 100 μmol·m−2·s−1 of blue light, simultaneous irradiation with 50 μmol·m−2·s−1 of blue light and 50 μmol·m−2·s−1 of red light, and 100 μmol·m−2·s−1 of red light. At the end of the light treatment, that is 17 days after sowing (DAS), the leaf area and shoot fresh weight (FW) of the lettuce seedlings treated with red light increased by 33% and 25%, respectively, and the dry weight of the shoots and roots of the lettuce seedlings treated with blue-containing LED lights increased by greater than 29% and greater than 83% compared with seedlings grown under a white fluorescent lamp (FL). The shoot/root ratio and specific leaf area of plants irradiated with blue-containing LED lights decreased. At 45 DAS, higher leaf areas and FWs were obtained in lettuce plants treated with blue-containing LED lights. The total chlorophyll (Chl) contents in lettuce plants treated with blue-containing and red lights were less than that of lettuce plants treated with FL, but the Chl a/b ratio and carotenoid content increased under blue-containing LED lights. Polyphenol contents and the total antioxidant status (TAS) were greater in lettuce seedlings treated with blue-containing LED lights than in those treated with FL at 17 DAS. The higher polyphenol contents and TAS in lettuce seedlings at 17 DAS decreased in lettuce plants at 45 DAS. In conclusion, our results indicate that raising seedlings treated with blue light promoted the growth of lettuce plants after transplanting. This is likely because of high shoot and root biomasses, a high content of photosynthetic pigments, and high antioxidant activities in the lettuce seedlings before transplanting. The compact morphology of lettuce seedlings treated with blue LED light would be also useful for transplanting.

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JANCIN, BRUCE. "Home-Based LED: Blue Light Gets Green Light." Skin & Allergy News 40, no. 5 (May 2009): 36. http://dx.doi.org/10.1016/s0037-6337(09)70217-7.

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Jung, Conrad H. G., Peter Waldeck, Shadi Sykora, Steffen Braune, Ingolf Petrick, Jan-Heiner Küpper, and Friedrich Jung. "Influence of Different Light-Emitting Diode Colors on Growth and Phycobiliprotein Generation of Arthrospira platensis." Life 12, no. 6 (June 15, 2022): 895. http://dx.doi.org/10.3390/life12060895.

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Light-emitting diodes (LED) can be utilized as tailorable artificial light sources for the cultivation of cyanobacteria such as Arthrospira platensis (AP). To study the influence of different LED light colors on phototrophic growth and biomass composition, AP was cultured in closed bioreactors and exposed to red, green, blue, or white LED lights. The illumination with red LED light resulted in the highest cell growth and highest cell densities compared to all other light sources (order of cell densities: red > white > green > blue LED light). In contrast, the highest phycocyanin concentrations were found when AP was cultured under blue LED light (e.g., order of concentrations: blue > white > red > green LED light). LED-blue light stimulated the accumulation of nitrogen compounds in the form of phycobiliproteins at the expense of cell growth. The results of the study revealed that exposure to different LED light colors can improve the quality and quantity of the biomass gained in AP cultures.

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Kim, Jun-Sub, and Ssang-Taek Steve Lim. "LED Light-Induced ROS Differentially Regulates Focal Adhesion Kinase Activity in HaCaT Cell Viability." Current Issues in Molecular Biology 44, no. 3 (March 4, 2022): 1235–46. http://dx.doi.org/10.3390/cimb44030082.

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In this study, changes in cell signaling mechanisms in skin cells induced by various wavelengths and intensities of light-emitting diodes (LED) were investigated, focusing on the activity of focal adhesion kinase (FAK) in particular. We examined the effect of LED irradiation on cell survival, the generation of intracellular reactive oxygen species (ROS), and the activity of various cell-signaling proteins. Red LED light increased cell viability at all intensities, whereas strong green and blue LED light reduced cell viability, and this effect was reversed by NAC or DPI treatment. Red LED light caused an increase in ROS formation according to the increase in the intensity of the LED light, and green and blue LED lights led to sharp increases in ROS formation. In the initial reaction to LEDs, red LED light only increased the phosphorylation of FAK and extracellular-signal regulated protein kinase (ERK), whereas green and blue LED lights increased the phosphorylation of inhibitory-κB Kinase α (IKKα), c-jun N-terminal kinase (JNK), and p38. The phosphorylation of these intracellular proteins was reduced via FAK inhibitor, NAC, and DPI treatments. Even after 24 h of LED irradiation, the activity of FAK and ERK appeared in cells treated with red LED light but did not appear in cells treated with green and blue LED lights. Furthermore, the activity of caspase-3 was confirmed along with cell detachment. Therefore, our results suggest that red LED light induced mitogenic effects via low levels of ROS–FAK–ERK, while green and blue LED lights induced cytotoxic effects via cellular stress and apoptosis signaling resulting from high levels of ROS.

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König, Yanyan, C. Huchzermeyer, and Hans Drexler. "Blaulichtgefährdung der Augen durch Lichtemittierende Dioden (LED)?" ASU Arbeitsmedizin Sozialmedizin Umweltmedizin 2020, no. 02 (January 31, 2020): 109–13. http://dx.doi.org/10.17147/asu-2002-8657.

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Blue light from light-emitting diodes (LED): a risk to the eyes? Background: In occupational and domestic environments people are increasingly exposed to artificial light from light-emitting diodes (LEDs). LEDs have peak emission in the blue range. In this review, we summarise the current knowledge of the possible effects of blue light exposure on ocular health. Effects of blue light on the regulation of physiological functions will be considered elsewhere. Methods: We performed a narrative review. We included preclinical data as well as epidemiological studies. We searched MEDLINE, Pubmed, the Cochrane Library and International Standard Randomised Controlled Trial Number (ISRCTN)-Register clinical trial registers from 01 January 2014 to 31 May 2019. Results: The accumulated experimental evidence obtained from different experimental models has indicated that excessive exposure to blue light can induce damage in the retinal pigment epithelium (RPE), in photoreceptors and ganglion cells. Previous epidemiological findings are equivocal regarding any causal links between blue light exposure and the development of macular degeneration (AMD). In vitro and in vivo evidence suggests that blue light exposure may influence the progression of uveal melanoma. Conclusions: Long-term effects of LEDs on ocular health cannot be definitively assessed on the basis of current knowledge. Susceptibility to blue light damage varies among the different species. The severity of light-induced retinal damage changes with the time of the day and depends on the diet and genetic background. Additional studies on the safety of long-term exposure to low levels of blue light are needed to determine the safety of LEDs for ocular health. Keywords: blue light – light-emitting diode – macular degeneration – uveal melanoma

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Jung, Myoung Hoon, Seok-Jun Yang, Ju Sung Yuk, Sang-Young Oh, Chang-Jin Kim, Jungmook Lyu, and Eun Jung Choi. "Evaluation of Blue Light Hazards in LED Lightings." Journal of Korean Ophthalmic Optics Society 20, no. 3 (September 30, 2015): 293–300. http://dx.doi.org/10.14479/jkoos.2015.20.3.293.

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Brgoch, Jakoah, and Shruti Hariyani. "(Invited) Advancing Human-Centric Lighting." ECS Meeting Abstracts MA2022-02, no. 51 (October 9, 2022): 1958. http://dx.doi.org/10.1149/ma2022-02511958mtgabs.

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The concept of human-centric lighting stems from the evolution of sunlight’s intensity and color temperature throughout the course of a day. This natural progression of bright cold-white light during the middle of the day to a softer warm-white light in the evening stimulates intrinsic photosensitive retinal ganglion cells that control our circadian rhythm. The blue-hue of daylight activates these cells to produce dopamine and cortisol while suppressing melatonin, the sleep hormone, to keep humans awake and alert. The current generation of energy-efficient LED lights reproduce daylight by converting a blue-emitting LED into a broad-spectrum white light using inorganic phosphors. Unfortunately, the resulting intense blue-hue generated by cheap LED bulbs and the underlying blue light from even the most expensive bulbs have been shown to cause macular degeneration, cataract formation, mood disorders, and circadian disruption, resulting in insomnia and fatigue. This talk will investigate the production of a ‘human-centric’ light that minimizes blue light by using a violet LED chip and inorganic phosphors. We report a new phosphor, Na2MgPO4F:Eu2+, which can be readily excited by violet light to produce a bright blue emission. This material possesses all the necessary requirements for LED lighting, including a high quantum yield, thermally robust emission, and impressive chemical stability. Incorporating this material into a prototype device demonstrates our ability produce a warm-white light with a higher color rendering index than a commercially purchased LED light bulb while significantly reducing the blue component.

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Ebbesen, Finn, Hendrik Jan Vreman, and Thor Willy Ruud Hansen. "Blue-Green (~480 nm) versus Blue (~460 nm) Light for Newborn Phototherapy—Safety Considerations." International Journal of Molecular Sciences 24, no. 1 (December 27, 2022): 461. http://dx.doi.org/10.3390/ijms24010461.

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We have previously shown that the phototherapy of hyperbilirubinemic neonates using blue-green LED light with a peak wavelength of ~478 nm is 31% more efficient for removing unconjugated bilirubin from circulation than blue LED light with a peak wavelength of ~452 nm. Based on these results, we recommended that the phototherapy of hyperbilirubinemic newborns be practiced with light of ~480 nm. Aim: Identify and discuss the most prominent potential changes that have been observed in the health effects of phototherapy using either blue fluorescent- or blue LED light and speculate on the expected effects of changing to blue-green LED light phototherapy. Search the phototherapy literature using the terms neonate, hyperbilirubinemia, and phototherapy in the PubMed and Embase databases. Transitioning from blue fluorescent light to blue-green LED light will expose neonates to less light in the 400–450 nm spectral range, potentially leading to less photo-oxidation and geno-/cytotoxicity, reduced risk of cancer, and decreased mortality in extremely low-birthweight neonates. The riboflavin level may decline, and the increased production and retention of bronze pigments may occur in predisposed neonates due to enhanced lumirubin formation. The production of pre-inflammatory cytokines may rise. Hemodynamic responses and transepidermal water loss are less likely to occur. The risk of hyperthermia may decrease with the use of blue-green LED light and the risk of hypothermia may increase. Parent–neonate attachment and breastfeeding will be positively affected because of the shortened duration of phototherapy. The latter may also lead to a significant reduction in the cost of phototherapy procedures as well as the hospitalization process.

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Le, Anh Tuan, Ju-Kyung Yu, Gyung-Deok Han, Thuong Kiet Do, and Yong-Suk Chung. "Potential Use of Colored LED Lights to Increase the Production of Bioactive Metabolites Hedyotis corymbosa (L.) Lam." Plants 11, no. 2 (January 15, 2022): 225. http://dx.doi.org/10.3390/plants11020225.

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Hedyotis corymbosa (L.) Lam is a wild herb that is used in traditional Indian, Chinese, and African medicine. Light-emitting diode (LED) technology is paving the way to enhance crop production and inducing targeted photomorphogenic, biochemical, or physiological responses in plants. This study examines the efficiency of H. corymbosa (L.) Lam production under blue 450 nm and red 660 nm LED lights for overall plant growth, photosynthetic characteristics, and the contents of metabolite compounds. Our research showed that blue LED lights provided a positive effect on enhancing plant growth and overall biomass. In addition, blue LED lights are more effective in controlling the production of sucrose, starch, total phenolic compounds, and total flavonoid compared to red LED lights. However, blue and red LED lights played essential but different roles in photosynthetic characteristics. Our results showed the potential of colored LED light applications in improving farming methods and increasing metabolite production in herbs.

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Radi, Radi, Yuwan Nanda Adyatma, and Makbul Hajad. "Optimization of Fooder Sorghum (Sorghum Bicolor L. Moench) Growth in a Closed Hydroponic System Through Combination of Red and Blue LED Lighting." Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) 11, no. 2 (June 30, 2022): 314. http://dx.doi.org/10.23960/jtep-l.v11i2.314-324.

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Plant cultivation with a closed hydroponic system needs to be developed as a food production solution in the future. With this technology, plant growth parameters (including light parameters) can be adjusted according to needs so that plants can grow optimally. Red and blue light are needed for sorghum cultivation. This study aims to analyze the effect of the combination of red and blue LED lights on the growth of sorghum plants and determine the optimal ratio between the two light sources based on the plant growth rate in a closed hydroponic system. The plant growth parameters measured included plant height, stem diameter, number of leaves, leaf area, leaf color, wet weight, dry weight, water consumption, and morphology of sorghum plants. This research is conducted by constructing the nine combination of red and blue LED light with the control system placed inside each closed hydroponic box. The results confirmed that the use of red and blue LED light combinations has a significant effect on the growth rate of sorghum. The optimum combination of red and blue LED light is obtained from combination of R7:B1 with the conversion ratio of 9.53 kg fresh product per kg sorghum seed. Keywords: Closed Hydroponic System, Control Systems, Growth Optimization, Sorghum Plant, Red And Blue LED Light

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Honglei Li, Honglei Li, Yini Zhang Yini Zhang, Xiongbin Chen Xiongbin Chen, Chunhui Wu Chunhui Wu, Junqing Guo Junqing Guo, Zongyu Gao Zongyu Gao, and Hongda Chen Hongda Chen. "High-speed phosphorescent white LED visible light communications without utilizing a blue filter." Chinese Optics Letters 13, no. 8 (2015): 080605–80609. http://dx.doi.org/10.3788/col201513.080605.

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Ying, Qinglu, Yun Kong, and Youbin Zheng. "Growth and Appearance Quality of Four Microgreen Species under Light-emitting Diode Lights with Different Spectral Combinations." HortScience 55, no. 9 (September 2020): 1399–405. http://dx.doi.org/10.21273/hortsci14925-20.

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To investigate plant growth and quality responses to different light spectral combinations, cabbage (Brassica oleracea L. var. capitata f. rubra), kale (Brassica napus L. ‘Red Russian’), arugula (Eruca sativa L.), and mustard (Brassica juncea L. ‘Ruby steak’) microgreens were grown in a controlled environment using sole-source light with six different spectra: 1) FL: cool white fluorescent light; 2) BR: 15% blue and 85% red light-emitting diode (LED); 3) BRFRL: 15% blue, 85% red, and 15.5 µmol·m−2·s−1 far-red (FR) LED; 4) BRFRH: 15% blue, 85% red, and 155 µmol·m−2·s−1 FR LED; 5) BGLR: 9% blue, 6% green, and 85% red LED; and 6) BGHR: 5% blue, 10% green, and 85% red LED. For all the light treatments, the total photosynthetic photon flux density (PPFD) was set at ≈330 µmol·m−2·s−1 under a 17-hour photoperiod, and the air temperature was ≈21 °C with 73% relative humidity (RH). At harvest, BR vs. FL increased plant height for all the tested species except arugula, and enlarged cotyledon area for kale and arugula. Adding high-intensity FR light to blue and red light (i.e., BRFRH) further increased plant height for all species, and cotyledon area for mustard, but it did not affect the fresh or dry biomass for any species. Also, BRFRH vs. BR increased cotyledon greenness for green-leafed species (i.e., arugula, cabbage, and kale), and reduced cotyledon redness for red-leafed mustard. However, BGLR, BGHR, and BRFRL, compared with BR, did not affect plant height, cotyledon area, or fresh or dry biomass. These results suggest that the combination of 15% blue and 85% red LED light can potentially replace FL as the sole light source for indoor production of the tested microgreen species. Combining high-intensity FR light, rather than low-level (≤10%) green light, with blue and red light could be taken into consideration for the optimization of LED light spectral quality in microgreen production under environmental conditions similar to this experiment.

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Sun, Yanbin, Jiaxing Zhang, Jilin Xu, Jiayi Cao, and Yanrong Li. "The Effects of Different LED Lights on the Main Nutritional Compositions of Isochrysis zhanjiangensis." Fishes 8, no. 3 (February 22, 2023): 124. http://dx.doi.org/10.3390/fishes8030124.

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Light irradiation plays an important role in the growth of microalgae and their nutrient composition. To elucidate the effect of different LED lights (red, orange, green, blue, purple, simulated sunlight, and white) on the main nutritional compositions of Isochrysis zhanjiangensis, the growth, fatty acid composition, soluble carbohydrate, and soluble protein contents were studied. The results show that I. zhanjiangensis grew the fastest under blue light (p = 0.044). In terms of fatty acid composition, the percentage of myristic acid (C14:0) decreased significantly (p = 0.021) under blue light and simulated sunlight, but the percentages of palmitic acid (C16:0) (p = 0.032) and stearic acid (C18:0) (p = 0.037) significantly increased. The percentage of docosahexaenoic acid (C22:6n-3) increased under orange light (p = 0.021), and the percentage of total unsaturated fatty acids increased under blue light (p = 0.008). The protein content significantly increased under simulated sunlight (p = 0.025), while the carbohydrate content did not vary much (p > 0.05) under different lights. These findings provide useful guidance for optimizing the cultivation conditions of I. zhanjiangensis to improve its nutritional value and yield.

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Park, Chang, Nam Kim, Jong Park, Sook Lee, Jong-Won Lee, and Sang Park. "Effects of Light-Emitting Diodes on the Accumulation of Glucosinolates and Phenolic Compounds in Sprouting Canola (Brassica napus L.)." Foods 8, no. 2 (February 19, 2019): 76. http://dx.doi.org/10.3390/foods8020076.

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In this study, we investigated optimal light conditions for enhancement of the growth and accumulation of glucosinolates and phenolics in the sprouts of canola (Brassica napus L.). We found that the shoot lengths and fresh weights of red light-irradiated sprouts were higher than those of sprouts exposed to white, blue, and blue + red light, whereas root length was not notably different among red, blue, white, and blue + red light treatments. The accumulations of total glucosinolates in plants irradiated with white, blue, and red lights were not significantly different (19.32 ± 0.13, 20.69 ± 0.05, and 20.65 ± 1.70 mg/g dry weight (wt.), respectively). However, sprouts exposed to blue + red light contained the lowest levels of total glucosinolates (17.08 ± 0.28 mg/g dry wt.). The accumulation of total phenolic compounds was the highest in plants irradiated with blue light (3.81 ± 0.08 mg/g dry wt.), 1.33 times higher than the lowest level in plants irradiated with red light (2.87 ± 0.05 mg/g dry wt.). These results demonstrate that red light-emitting diode (LED) light is suitable for sprout growth and that blue LED light is effective in increasing the accumulation of glucosinolates and phenolics in B. napus sprouts.

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Weremczuk-Jeżyna, Izabela, Katarzyna Hnatuszko-Konka, Liwia Lebelt, and Izabela Grzegorczyk-Karolak. "The Protective Function and Modification of Secondary Metabolite Accumulation in Response to Light Stress in Dracocephalum forrestii Shoots." International Journal of Molecular Sciences 22, no. 15 (July 26, 2021): 7965. http://dx.doi.org/10.3390/ijms22157965.

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The aim of this work was to determine the effect of stress conditions caused by different light sources, i.e., blue LED (λ = 430 nm), red LED (λ = 670 nm), blue and red LED (70%:30%) and white LED (430–670 nm) on the growth and morphology of cultivated in vitro Dracocephalum forrestii shoot culture. It also examines the effects on bioactive phenolic compound production and photosynthetic pigment content, as well as on antioxidant enzyme activity (CAT, SOD, POD) and antioxidant properties. The most beneficial proliferation effect was observed under white LEDs (7.1 ± 2.1 shoots per explant). The white and blue lights stimulated the highest fresh weight gain, while red light induced the highest dry weight gain. The total phenolic acid content ranged from 13.824 ± 1.181 to 20.018 ± 801 mg g DW−1 depending on light conditions. The highest content of rosmarinic acid was found in the control shoots (cultivated under fluorescent lamps), followed by culture grown under red light. All LED treatments, especially red and blue, increased salvianolic acid B content, and blue increased apigenin p-coumarylrhamnoside biosynthesis. The greatest ferric reduction activity was observed in shoots cultivated under red light, followed by blue; this is associated with the presence of the highest total phenol content, especially phenolic acids. Similarly, the highest DPPH radical scavenging potential was observed under red light followed by blue. This study proves that LEDs have emerged as significant support for directed in vitro propagation, taking advantage of specific stress responses on various light spectra. This study also showed how stress induced by different LED light spectra increases in Dracocephalum forrestii the synthesis of pharmacologically-active compounds. Hence, light stress may turn out to be a simpler alternative to metabolic engineering for improving the production of secondary metabolites of therapeutic value.

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Rauch, M., S. Schmidt, I. W. C. E. Arends, K. Oppelt, S. Kara, and F. Hollmann. "Photobiocatalytic alcohol oxidation using LED light sources." Green Chemistry 19, no. 2 (2017): 376–79. http://dx.doi.org/10.1039/c6gc02008a.

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Li, Mingcai, Xuejie Zhang, Haoran Zhang, Weibin Chen, Li Ma, Xiaojun Wang, Yingliang Liu, and Bingfu Lei. "Highly efficient and dual broad emitting light convertor: an option for next-generation plant growth LEDs." Journal of Materials Chemistry C 7, no. 12 (2019): 3617–22. http://dx.doi.org/10.1039/c8tc06115g.

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At present, blue-red composite LED light sources used for plant lighting are mainly composed of blue light and red light; the blue light is provided by gallium nitride LED chips, but the full-width at half-maximum (FWHW) is only approximately 25 nm, while the blue light required by plants for photosynthesis is wider.

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Kaptsov, V. A., and V. N. Deinego. "Blue LED light as a new hygienic problem." Health Risk Analysis, no. 1 (January 2016): 15–25. http://dx.doi.org/10.21668/health.risk/2016.1.02.

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Kaptsov, V. A., and V. N. Deinego. "Blue LED light as a new hygienic problem." Health Risk Analysis, no. 1 (January 2016): 15–25. http://dx.doi.org/10.21668/health.risk/2016.1.02.eng.

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Lafuente, María T., and Fernando Alférez. "Effect of LED Blue Light onPenicillium digitatumandPenicillium italicumStrains." Photochemistry and Photobiology 91, no. 6 (October 7, 2015): 1412–21. http://dx.doi.org/10.1111/php.12519.

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Cioć, Monika, and Bożena Pawłowska. "Leaf Response to Different Light Spectrum Compositions during Micropropagation of Gerbera Axillary Shoots." Agronomy 10, no. 11 (November 22, 2020): 1832. http://dx.doi.org/10.3390/agronomy10111832.

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The experiment evaluated the influence of different light qualities and 6-benzyladenine (BA) concentration in a medium on the leaf response of multiplied Gerbera jamesonii Bolus ex Hook. f.‘Big Apple’ shoots. Three different light-emitting diode (LED) spectra—100% blue (B), 100% red (R) and red and blue mixture (7:3, RB)—were used, and a fluorescent lamp was used as a control (Fl). Concentrations of BA in Murashige and Skoog (MS) medium were 1, 2.5 and 5 µM. Leaves developed under 100% blue light had a lower frequency of stomata and a smaller area as compared with those from plants exposed to light with red in spectrum. Under 100% red light, the leaf area and the frequency of stomata increased along with growing concentration of BA in the medium. The thickest mesophyll was spotted in the cross-section of leaves exposed to the blue LED light. Leaves developed under the 100% red light had the thinnest mesophyll layers. Increasing concentration of BA in the medium resulted in enhanced leaf blade thickness. The cross-section of leaf vascular bundles was only half of that in petioles. The leaves under the LED combinations had larger vascular bundles than those under fluorescent light. The highest level of photosynthetic pigments was noticed in the leaves grown under LED R and RB lights. Our study demonstrated that 2.5 µM BA and a mixture of blue and red light provided by LED improved leaf quality during multiplication of gerbera shoots.

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Lin, Chao-Wen, Chung-May Yang, and Chang-Hao Yang. "Protective Effect of Astaxanthin on Blue Light Light-Emitting Diode-Induced Retinal Cell Damage via Free Radical Scavenging and Activation of PI3K/Akt/Nrf2 Pathway in 661W Cell Model." Marine Drugs 18, no. 8 (July 25, 2020): 387. http://dx.doi.org/10.3390/md18080387.

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Light-emitting diodes (LEDs) are widely used and energy-efficient light sources in modern life that emit higher levels of short-wavelength blue light. Excessive blue light exposure may damage the photoreceptor cells in our eyes. Astaxanthin, a xanthophyll that is abundantly available in seafood, is a potent free radical scavenger and anti-inflammatory agent. We used a 661W photoreceptor cell line to investigate the protective effect of astaxanthin on blue light LED-induced retinal injury. The cells were treated with various concentrations of astaxanthin and then exposed to blue light LED. Our results showed that pretreatment with astaxanthin inhibited blue light LED-induced cell apoptosis and prevented cell death. Moreover, the protective effect was concentration dependent. Astaxanthin suppressed the production of reactive oxygen species and oxidative stress biomarkers and diminished mitochondrial damage induced by blue light exposure. Western blot analysis confirmed that astaxanthin activated the PI3K/Akt pathway, induced the nuclear translocation of Nrf2, and increased the expression of phase II antioxidant enzymes. The expression of antioxidant enzymes and the suppression of apoptosis-related proteins eventually protected the 661W cells against blue light LED-induced cell damage. Thus, our results demonstrated that astaxanthin exerted a dose-dependent protective effect on photoreceptor cells against damage mediated by blue light LED exposure.

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Song, Dae-Gyu, Junseok Lee, Hong-Jin Choi, and Jeong-Koo Kim. "Study on Contact Lens That Blocks Blue Light from LED." Polymer Korea 46, no. 1 (January 31, 2022): 62–67. http://dx.doi.org/10.7317/pk.2022.46.1.62.

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de Vries, Lana J., Frank van Langevelde, Coby van Dooremalen, Ilse G. Kornegoor, Martin J. Lankheet, Johan L. van Leeuwen, Marc Naguib, and Florian T. Muijres. "Bumblebees land remarkably well in red–blue greenhouse LED light conditions." Biology Open 9, no. 6 (May 6, 2020): bio046730. http://dx.doi.org/10.1242/bio.046730.

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ABSTRACTRed–blue emitting LEDs have recently been introduced in greenhouses to optimise plant growth. However, this spectrum may negatively affect the performance of bumblebees used for pollination, because the visual system of bumblebees is more sensitive to green light than to red–blue light. We used high-speed stereoscopic videography to three-dimensionally track and compare landing manoeuvres of Bombus terrestris bumblebees in red–blue light and in regular, broad-spectrum white light. In both conditions, the landing approaches were interspersed by one or several hover phases, followed by leg extension and touchdown. The time between leg extension and touchdown was 25% (0.05 s) longer in red–blue light than in white light, caused by a more tortuous flight path in red–blue light. However, the total landing duration, specified as the time between the first hover phase and touchdown, did not differ between the light conditions. This suggests that the negative effects of red–blue light on the landing manoeuvre are confined to the final phase of the landing.This article has an associated First Person interview with the first author of the paper.

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Chung, Ill-Min, Changhwan Lee, Myeong Ha Hwang, Seung-Hyun Kim, Hee-Yeon Chi, Chang Yeon Yu, Ramachandran Chelliah, Deog-Hwan Oh, and Bimal Kumar Ghimire. "The Influence of Light Wavelength on Resveratrol Content and Antioxidant Capacity in Arachis hypogaeas L." Agronomy 11, no. 2 (February 9, 2021): 305. http://dx.doi.org/10.3390/agronomy11020305.

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The quality and intensity of light can have a huge influence on plant growth and bioactive compound production. Compared to conventional lighting, very little is known about the influence of light emitting diodes (LED) irradiation on the antioxidant and antimicrobial properties and resveratrol content of peanut sprouts. This study was aimed at understanding the effects of LED light on the growth and antioxidant capacity of peanut sprouts. The resveratrol concentration was determined by liquid chromatography–tandem mass spectrometry. Peanut sprouts grown under blue LED light exhibited a higher total resveratrol content grown than those under fluorescent light and other LED light sources. The highest total phenolic content was recorded in the case of blue LED. The 1,1-diphenyl-2-picrylhydrazyl and 2,2-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid radical scavenging values of blue LED‒treated and micro-electrodeless light-treated sprouts were significantly (p < 0.05) higher than that of sprouts grown under lights with other wavelengths. A Pearson correlation analysis revealed a strong association of the resveratrol, total phenolic, and flavonoid contents of peanut sprouts with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS), indicating its contribution to antioxidant activities. The anti-tyrosinase activity increased with an increase in the concentration of the tested sample. Blue LED-irradiated peanut extracts at a selected concentration range showed moderate cytotoxicity. Furthermore, the antimicrobial activity of peanut sprouts grown under blue LED was effective against Escherichia coli, Klebsiella pneumonia, and Vibrio litoralis. The present study revealed that the application of LEDs during the peanut sprouts growth improves the antioxidant activity, resveratrol concentration, and metabolite accumulation.

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Zhang, Xianchen, Keyang Chen, Ziyi Zhao, Siya Li, and Yeyun Li. "A Novel LED Light Radiation Approach Enhances Growth in Green and Albino Tea Varieties." Plants 12, no. 5 (February 21, 2023): 988. http://dx.doi.org/10.3390/plants12050988.

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Light, as an energy source, has been proven to strongly affect photosynthesis and, thus, can regulate the yield and quality of tea leaves (Camellia sinensis L.). However, few comprehensive studies have investigated the synergistic effects of light wavelengths on tea growth and development in green and albino varieties. Thus, the objective of this study was to investigate different ratios of red, blue and yellow light and their effects on tea plants’ growth and quality. In this study, Zhongcha108 (green variety) and Zhongbai4 (albino variety) were exposed to lights of different wavelengths for a photoperiod of 5 months under the following seven treatments: white light simulated from the solar spectrum, which served as the control, and L1 (red 75%, blue 15% and yellow 10%), L2 (red 60%, blue 30% and yellow 10%), L3 (red 45%, far-red light 15%, blue 30% and yellow 10%), L4 (red 55%, blue 25% and yellow 20%), L5 (red 45%, blue 45% and yellow 10%) and L6 (red 30%, blue 60% and yellow 10%), respectively. We examined how different ratios of red light, blue light and yellow light affected tea growth by investigating the photosynthesis response curve, chlorophyll content, leaf structure, growth parameters and quality. Our results showed that far-red light interacted with red, blue and yellow light (L3 treatments) and significantly promoted leaf photosynthesis by 48.51% in the green variety, Zhongcha108, compared with the control treatments, and the length of the new shoots, number of new leaves, internode length, new leaf area, new shoots biomass and leaf thickness increased by 70.43%, 32.64%, 25.97%, 15.61%, 76.39% and 13.30%, respectively. Additionally, the polyphenol in the green variety, Zhongcha108, was significantly increased by 15.6% compared to that of the plants subjected to the control treatment. In addition, for the albino variety Zhongbai4, the highest ratio of red light (L1 treatment) remarkably enhanced leaf photosynthesis by 50.48% compared with the plants under the control treatment, resulting in the greatest new shoot length, number of new leaves, internode length, new leaf area, new shoot biomass, leaf thickness and polyphenol in the albino variety, Zhongbai4, compared to those of the control treatments, which increased by 50.48%, 26.11%, 69.29%, 31.61%, 42.86% and 10.09%, respectively. Our study provided these new light modes to serve as a new agricultural method for the production of green and albino varieties.

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Esmaeili-Rad, Mohammad R., Nikolas P. Papadopoulos, Marius Bauza, Arokia Nathan, and William S. Wong. "Blue-Light-Sensitive Phototransistor for Indirect X-Ray Image Sensors." IEEE Electron Device Letters 33, no. 4 (April 2012): 567–69. http://dx.doi.org/10.1109/led.2012.2185676.

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Lan, Hao-Yu, I.-Chen Tseng, Yung-Hsiang Lin, Shu-Wei Chang, and Chao-Hsin Wu. "Characteristics of Blue GaN/InGaN Quantum-Well Light-Emitting Transistor." IEEE Electron Device Letters 41, no. 1 (January 2020): 91–94. http://dx.doi.org/10.1109/led.2019.2955733.

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Khac Hung, Nguyen, Do Thi Gam, Hoang Thi Huyen Trang, Chu Hoang Ha, Do Tien Phat, and Pham Bich Ngoc. "Effects of blue and red LED lights on rubisco activase gene expression, CO2 fixation efficiency and plant morphology of Gerbera jamesonii." Vietnam Journal of Biotechnology 20, no. 3 (September 30, 2022): 467–77. http://dx.doi.org/10.15625/1811-4989/16043.

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Light quality is known to affects numerous plants’ physiological and metabolic processes during development period, including photosynthesis and morphogenesis. Light properties such as light wavelength has been optimized for several cultivated crops. In this study, the effects of LED light wavelengths blue and red on both photosynthetic performance and morphology of Gerbera jamesonii plantlets was investigated. The results showed the photosynthesis efficiency via the photo-pigment system and mediated regulation of rubisco activase encoding gene (RCA) mechanism was significantly enhanced by blue light. The expression of RCA was approximatly 2.7 times higher than those under red light. In contrast, chlorophyll contents, CO2 assimilation, total carbohydrate and RCA expression was reduced under red wavelength. However, both single-wavelengths caused a dramatically negative impact on G. jamesonii. Total chlorophyll/carotenoid value or higher carotenoid contents was lower under blue light; fragile petioles and drawrfism morphology was occurred under red and blue LED, respectively. The combination of blue and red light in the lighting spectrum significantly improved the limitations of single-wavelength. The supplement of blue light under red light background (at blue LED and red LED ratio = 1:4) improved plant photosynthesis while maintained the normal morphology of plants, although the expression of RCA and net photosynthesis of plants in BR LED was lower than in the control. Our results obviously provide the scientific evidences for requirement of LED light in micropropagation or canopy culture of G. jamesonii.

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Mpai, Semakaleng, and Dharini Sivakumar. "Stimulation of Light-Emitting Diode Treatment on Defence System and Changes in Mesocarp Metabolites of Avocados Cultivars (Hass and Fuerte) during Simulated Market Shelf Conditions." Agronomy 10, no. 11 (October 27, 2020): 1654. http://dx.doi.org/10.3390/agronomy10111654.

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The ability of light-emitting diode (LED) light treatment to reduce the anthracnose decay via its eliciting effects and thus induce resistance in the avocado (Persea americana), was investigated in this study to replace the current postharvest fungicide treatment. In experiment 1, the effect of blue or red LED lights (6 h per day) on the incidence of anthracnose in artificially inoculated (Colletotrichum gloesposorioides) and naturally infected avocados (cv. Fuerte and Hass) at 12–14 °C (simulated market shelf) for 4, 8, 14, and 16 days was investigated. In experiment 2, the effect of blue or red LED lights on the induced defence mechanism, fruit metabolites, antioxidant activity, and percentage of fruit reaching ready-to-eat stage was determined. Exposure to red LED light significantly reduced the anthracnose decay incidence in naturally infected cv. Fuerte on day 12 and in cv. Hass on day 16 compared to the prochloraz fungicide treatment by upregulating the PAL genes and maintaining the epicatechin content. Blue LED light accelerated the ripening in both cultivars, probably due to reduced D-mannoheptulose content. Red LED light exposure for 6 h per day and 12 days storage showed potential to replace the prochloraz treatment with improved ascorbic acid content and antioxidant activity.

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WANG, YAN, FUGEN WU, XIN ZHANG, YUANWEI YAO, HUILIN ZHONG, SHUYA YAN, and YUN HE. "ENHANCEMENT OF LIGHT EXTRACTING FROM GaN-BASED BLUE LIGHT EMITTING DIODES USING PHOTONIC CRYSTAL." Modern Physics Letters B 26, no. 12 (April 26, 2012): 1250071. http://dx.doi.org/10.1142/s0217984912500716.

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Photonic crystal (PC) structures on LED have been known to enhance the light extraction significantly. In this paper, we report the light energy of GaN -based blue lighting emitting diode (LED) with perfect area photonic crystal (PPC) structure and defect area photonic crystal (DPC) structure. As a result, the light extracting energy of LEDs with PPC structure enhanced little compared to that of without PC structure. In addition, the light extracting energy of blue LED with DPC structure was remarkably improved.

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Park, Chang Ha, Ye Eun Park, Hyeon Ji Yeo, Jae Kwang Kim, and Sang Un Park. "Effects of Light-Emitting Diodes on the Accumulation of Phenolic Compounds and Glucosinolates in Brassica juncea Sprouts." Horticulturae 6, no. 4 (November 9, 2020): 77. http://dx.doi.org/10.3390/horticulturae6040077.

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Recent improvements in light-emitting diode (LED) technology afford an excellent opportunity to investigate the relationship between different light sources and plant metabolites. Accordingly, the goal of the present study was to determine the effect of different LED (white, blue, and red) treatments on the contents of glucosinolates (glucoiberin, gluconapin, sinigrin, gluconasturtiin, 4-methoxyglucobrassicin, 4-hydroxyglucobrassicin, glucobrassicin, and neoglucobrassicin) and phenolic compounds (4-hydroxybenzonate, catechin, chlorogenic acid, caffeate, gallate, sinapate, and quercetin) in Brassica juncea sprouts. The sprouts were grown in a growth chamber at 25 °C under irradiation with white, blue, or red LED with a flux rate of 90 μmol·m−2·s−1 and a long-day photoperiod (16 h light/8 h dark cycle). Marked differences in desulfoglucosinolate contents were observed in response to treatment with different LEDs and different treatment durations. In addition, the highest total desulfoglucosinolate content was observed in response to white LED light treatment, followed by treatment with red LED light, and then blue LED light. Among the individual desulfoglucosinolates identified in the sprouts, sinigrin exhibited the highest content, which was observed after three weeks of white LED light treatment. The highest total phenolic contents were recorded after one week of white and blue LED light treatment, whereas blue LED irradiation increased the production of most of the phenolic compounds identified, including 4-hydroxybenzonate, gallate, sinapate, caffeate, quercetin, and chlorogenic acid. The production of phenolics decreased gradually with increasing duration of LED light treatment, whereas anthocyanin accumulation showed a progressive increase during the treatment. These findings indicate that white LED light is appropriate for glucosinolate accumulation, whereas blue LED light is effective in increasing the production of phenolic compounds in B. juncea sprouts.

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Suada, I. Ketut, I. Gede Putu Wirawan, Rindang Dwiyani, Linawati Linawati, I. Nyoman Setiawan, Hery Suyanto, Ni Nyoman Suryantini, and Qomariah Qomariah. "Growth of Lettuce (Lactucasativa L.) Plant Under Red-Blue-White Light and Grow Light LEDs in Plant Factory System." International Journal of Environment, Agriculture and Biotechnology 6, no. 6 (2021): 146–52. http://dx.doi.org/10.22161/ijeab.66.18.

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Indoor culture requires a variety of inputs to get maximum biomass. These inputs are the nutrients, temperature, humidity, and light which plants needed to photosynthesize. Different types of light have been studied and it is known that the same spectrum will give different responses by different plants. The purpose of this study was to find out the effect of red-blue-white light LED on lettuce growth compared to grow light LED as a control which commonly used in plant factory rooms. The red-blue-white light is arranged on a 100 cm long aluminum rod, mounted along the plant in a gully DFT hydroponic fed by 1000-2000 ppm nutrients of ABmix plus with a pH of 5.5-6.5. LED grow light provided the plant a significantly higher height of 16.30% compared to red-blue-white light, but was no different to the length of lettuce root. The number and the area of leaves in red-blue-white light were markedly higher at 16.67% and 33.78% respectively than grow light. In addition, the red-blue-white light increased the chlorophyll content, fresh weight, and dry weight of lettuce plants, by 25.00%, 101.49% and 58.13% consecutively. Therefore, these results suggested that the red-blue-white LED light provided a significant higher biomass than the grow light LED.

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WAN MOHD NOOR, WAN NUR HIDAYAH, WAN ZALIHA WAN SEMBOK, and WAN ZAWIAH WAN ABDULLAH. "THE EFFECTS OF LIGHT-EMITTING DIODES (LED) IRRADIATION TREATMENT ON THE POSTHARVEST PRESERVATION AND MICROBIOLOGICAL QUALITY OF STRAWBERRY (Fragaria ananassa) CV. FESTIVAL." Universiti Malaysia Terengganu Journal of Undergraduate Research 3, no. 4 (October 31, 2021): 137–48. http://dx.doi.org/10.46754/umtjur.v3i4.247.

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Strawberry (Fragaria Ananassa sp.) is non-climacteric, aggregate fruit with a rich source of anthocyanin and vitamin C. However, strawberry has short storage life and is very susceptible to decay and physiological deterioration process. Therefore, emitting the post-harvest LED light to strawberries during cold storage has been studied. This work aimed to evaluate different LED light treatment effects to retain post-harvest quality and microbial quality of the strawberry. The post-harvest parameters that have been used are weight loss, colour, firmness, total soluble solids, titratable acidity, and pH. The microbial parameter such as Escherichia coli count, Salmonella count, total plate count, and mold count would also has been assessed. Strawberries were irradiated under three different LED light types (white, blue and red). Blue and red LED lights have different wavelengths, which are 470 nm and 630 nm. The strawberry fruits were stored at 5ºC in a cold room and study parameter were assessed in 10 days. There were statistically significant differences (p<0.05) between the treatment of weight loss, firmness, pH, and total soluble solid. The best treatment for this experiment is blue LED light which showed the lowest weight loss, retained the colour and delayed firmness loss of the strawberry. This study also proved that blue LED light could reduce the growth of E.coli. In conclusion, LED light produces minimal heat, which improves food safety and preserves post-harvest quality of strawberry.

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Maroga, Gludia M., Puffy Soundy, and Dharini Sivakumar. "Different Postharvest Responses of Fresh-Cut Sweet Peppers Related to Quality and Antioxidant and Phenylalanine Ammonia Lyase Activities during Exposure to Light-Emitting Diode Treatments." Foods 8, no. 9 (August 23, 2019): 359. http://dx.doi.org/10.3390/foods8090359.

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The influence of emitting diode (LED) treatments for 8 h per day on functional quality of three types of fresh-cut sweet peppers (yellow, red, and green) were investigated after 3, 7, 11, and 14 days postharvest storage on the market shelf at 7 °C. Red LED light (660 nm, 150 μmol m−2 s−1) reduced weight loss to commercially acceptable level levels (≤2.0%) in fresh-cuts of yellow and green sweet peppers at 7 and 11 d, respectively. Blue LED light (450 nm, 100 μmol m−2 s−1) maintained weight loss acceptable for marketing in red fresh-cut sweet peppers up to 11 d. Highest marketability with minimum changes in color difference (∆E) and functional compounds (total phenols, ascorbic acid content, and antioxidant activity) were obtained in yellow and green sweet pepper fresh-cuts exposed to red LED light up to 7 and 11 d, respectively, and for red sweet pepper fresh-cuts exposed to blue LED light for 11 d. Red LED light maintained the highest concentrations of β carotene, chlorophyll, and lycopene in yellow, green, and red sweet pepper fresh-cuts up to 7 d. Similarly, blue LED light showed the highest increase in lycopene concentrations for red sweet pepper fresh-cuts up to 7 d. Red LED (yellow and green sweet peppers) and blue LED (red sweet pepper) lights maintained phenolic compounds by increasing phenylalanine ammonia lyase activity. Thus, the results indicate a new approach to improve functional compounds of different types of fresh-cut sweet pepper.

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Sri Santiari, Dewa Ayu, and Mahadi Putra. "Kajian Area Penyinaran Dan Nilai Intensitas Pada Peralatan Blue Light Therapy." Majalah Ilmiah Teknologi Elektro 17, no. 2 (September 28, 2018): 279. http://dx.doi.org/10.24843/mite.2018.v17i02.p17.

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Kasus bayi kuning (hiperbilirubinemia) merupakan salah satu keadaan yang sering ditemukan pada bayi baru lahir. Salah satu tindakan untuk menurunkan tingkat bilirubin pada bayi kuning adalah dengan fototerapi menggunakan blue light therapy. Ada dua jenis peralatan blue light therapy yang saat ini dipergunakan pada ruang Cempaka di rumah sakit Sanglah, yaitu :blue light therapy lampu fluorescent dan blue light therapy lampu LED. Kedua jenis peralatan tersebut memiliki bentuk dan sumber cahaya yang berbeda. Hasil analisa bentuk sumber cahaya pada kedua peralatan therapy menunjukkan bahwa blue light therapy lampu fluorescent yang berbentuk persegi panjang akan menghasilkan area penyinaran yang lebih luas dari blue light therapy LED yang hanya menghasilkan area penyinaran terbatas pada permukaan bidang kerja.Berdasarkan pada area dan intensitas penyinaran yang dihasilkan oleh kedua bentuk blue light therapy maka dapat disimpulkan bahwa blue light therapy lampu fluorescent yang berbentuk persegi panjang pada jarak 30 cm akan menghasilkan area penyinaran yang lebih luas dengan nilai rata-rata intensitas yang lebih tinggi (12mW/cm2/nm) dibandingkan dengan blue light therapy LED yang hanya menghasilkan area penyinaran terbatas pada permukaan bidang kerja dengan nilai rata-rata intensitas yang lebih rendah (6 mW/cm2/nm).

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Rasiukevičiūtė, Neringa, Aušra Brazaitytė, Viktorija Vaštakaitė-Kairienė, Asta Kupčinskienė, Pavelas Duchovskis, Giedrė Samuolienė, and Alma Valiuškaitė. "The Effect of Monochromatic LED Light Wavelengths and Photoperiods on Botrytis cinerea." Journal of Fungi 7, no. 11 (November 16, 2021): 970. http://dx.doi.org/10.3390/jof7110970.

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Botrytis cinerea is a ubiquitous necrotrophic pathogen causing grey mould in economically important crops. Light effect in horticulture is undeniable and fungi also react to light. Selected specific light-emitting diodes (LEDs) and photoperiods can be used for fungal pathogen inhibition. This study aimed to evaluate how LED light wavelengths and photoperiods affect the growth parameters of B. cinerea. The morphological (mycelium appearance, sclerotia distribution) and phenotypic (conidia presence and size, mycelium growth rate, recovery) characteristics of the fungal pathogen B. cinerea were evaluated under royal blue 455 nm, blue 470 nm, cyan 505 nm, yellow 590 nm, and red 627 nm LED lights at various photoperiods (4, 8, 12, 16, 20, 24 h). The results revealed that the light conditions and photoperiods influenced the B. cinerea morphological and phenotypic characteristics. Overall, the highest B. cinerea inhibition was under yellow (590 nm) LED light at 4 and 8 h photoperiods. Conidia did not form under blue 455 nm at 8, 16, 20, and 24 h photoperiods. Therefore, it can be assumed that the phenotypic and morphological features of B. cinerea depend on the specific photoperiod and LED light wavelength. The results allowed an exploration of original research approaches, raised new scientific questions for further investigation, and suggested new green plant protection solutions.

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Matysiak, Bożena, and Artur Kowalski. "THE GROWTH, PHOTOSYNTHETIC PARAMETERS AND NITROGEN STATUS OF BASIL, CORIANDER AND OREGANO GROWN UNDER DIFFERENT LED LIGHT SPECTRA." Acta Scientiarum Polonorum Hortorum Cultus 20, no. 2 (April 26, 2021): 13–22. http://dx.doi.org/10.24326/asphc.2021.2.2.

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Growth, morphological parameters, photosynthetic performance and nitrogen status were investigated in leafy herbs grown in light-limited time in a greenhouse under different light spectra emitted by LEDs. Fluorescence-based sensors that detect crop N status and maximum photochemical efficiency of photosystem II were used in this study. Four light treatments with the ratio of Red, Blue and White LEDs including 1) R40 + B50 + W10, 2) R70 + B20 + W10, 3) R70 + B20 + W10 + Far-Red and 4) White LEDs as control were used in this study. Dominant red light and/or white LED lights at 200 µmol m–2 s–1 at plant level and a 12 h photoperiod provided the most favourable conditions for plant growth and development compared to a high proportion of blue light (R40 + B50 + W10). However, plants grown under a high proportion of blue light had a higher chlorophyll index and nitrogen balance index (NBI) than under dominant red light treatments. Our study indicates the significant potential of fluorescence-based sensors in photobiology research as well as in the production of leafy herbs under LED lights.

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Smith, Barbara J., Eric T. Stafne, Hamidou F. Sakhanokho, and Blair J. Sampson. "Intensity of Supplemental Greenhouse Lighting Affects Strawberry Plant Growth, Anthracnose Infection Response, and Colletotrichum Pathogen Development in Culture." HortScience 58, no. 1 (January 2023): 127–33. http://dx.doi.org/10.21273/hortsci16888-22.

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The effect of supplemental lighting on strawberry growth and anthracnose disease response of three strawberry (Fragaria ×ananassa) cultivars was evaluated in two greenhouse trials, and the effect on strawberry anthracnose pathogens (Colletotrichum sp.) was evaluated in the laboratory. The objective of the greenhouse trials was to determine the effect of various intensities of the red and blue light emitting diode (LED) light treatment on strawberry plant vigor, injury, and disease development. In these trials, the duration of supplemental light treatments was split into two 4-hour periods: dawn and dusk. The intensity of the red and blue LED bulbs was set using an adjustable dial at 1 or 3 in trial 1 and at 1, 5, or 10 in trial 2. Illuminance and photosynthetic photon flux densities of the light treatments ranged from lows of 402 lx and 5 μmol⋅m–2⋅s–1 (blue LED 1) to highs of 575 lx and 25 μmol⋅m–2⋅s–1 (red LED 1 + blue LED 3) in trial 1, and from lows of 4213 lx and 81 μmol⋅m–2⋅s–1 (red LED 1) to highs of 7051 lx (red LED 5) and 194 μmol⋅m–2⋅s–1 (red LED 10) in trial 2. Lower light intensities in trial 1 resulted in no significant differences as a result of light treatments in relative chlorophyll content, plant vigor ratings, or disease severity ratings (DSRs). However, plant injury ratings were significantly greater in plants in the wide-spectrum fluorescent (WSF) plus ultraviolet B (UVB) light treatment compared with the other treatments. Under the higher light intensities in trial 2, there were more significant effects among light treatments. Relative chlorophyll content of plants in the WSF + UVB, WSF, and red LED 1 treatments was significantly greater than that of plants in the red LED 10 treatment; however, plants in the red LED 10 treatment had the greatest injury ratings. Detached leaves from plants in the red 5 LED and red 10 LED treatments inoculated with Colletotrichum gloeosporioides received the greatest DSRs, and leaves from plants in the red LED 1 and WSF treatments received the lowest DSRs. In the laboratory, five days of exposure to supplemental lights did not prevent the growth of isolates of three species of Colletotrichum pathogens even though the intensity of the LED lights was set at their highest intensity. However, growth of isolates exposed to the WSF + UVB light treatment was slowed.

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Aldarkazali, Rihan, Carne, and Fuller. "The Growth and Development of Sweet Basil (Ocimum basilicum) and Bush Basil (Ocimum minimum) Grown under Three Light Regimes in a Controlled Environment." Agronomy 9, no. 11 (November 11, 2019): 743. http://dx.doi.org/10.3390/agronomy9110743.

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Light is a crucial element for plant growth and production. In areas where natural light is not sufficient for optimal plant growth and production, high pressure sodium (HPS) light sources are widely used. However, HPS lamps are considered not very electrically efficient generating high radiant heat and as a consequence, there has been a lot of interest in replacing HPS lamps with new more efficient lighting sources in the form of light-emitting diodes (LEDs). The effects of three lighting sources (White LED, Blue/Red LED and HPS) on the growth, development and on the essential oil yield and quality of sweet basil and bush basil were investigated. There was a clear advantage to the Blue/Red (452 nm and 632 nm, respectively) LED on virtually all growth and physiological parameters measured for both basil species. The HPS lighting system always performed least effectively in all comparisons. Combining increases in plant yield and increases in oil yield the Blue/Red LED array outperformed the HPS lights by a factor of approximately double, with the white LED being intermediate between these two extremes.

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Syväjärvi, Mikael, Rositza Yakimova, Motoaki Iwaya, Tetsuya Takeuchi, Isamu Akasaki, and Satoshi Kamiyama. "Growth and Light Properties of Fluorescent SiC for White LEDs." Materials Science Forum 717-720 (May 2012): 87–92. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.87.

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The LED technology started to developed many years ago with red light emitting diodes. To achieve the blue LED, novel growth technologies and process steps were explored, and made it possible to demonstrate efficient blue LED performance from nitrides. The efficiency was further developed and blue LEDs were commercially introduced in the 1990’s. The white LED became possible by the use of the blue LED and a phosphor that converts a part of the blue light to other colors in the visible range to combine into white light. However, even today there are limitations in the phosphor-based white LED technology, in particular for general lighting, and new solutions should be explored to speed the pace when white LEDs will be able to make substantial energy savings. In this paper we overview gallium nitride materials evolution and growth concepts for LEDs. We describe the fluorescent silicon carbide material prepared by a novel growth technology for a new type of white LED in general lighting with pure white light. This paper introduces an interesting research in fundamental growth and optical properties of light emitting silicon carbide.

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Wojciechowska, Renata, Anna Kołton, Olga Długosz-Grochowska, Edward Kunicki, Katarzyna Mrowiec, and Paweł Bathelt. "LED lighting affected the growth and metabolism of eggplant and tomato transplants in a greenhouse." Horticultural Science 47, No. 3 (September 30, 2020): 150–57. http://dx.doi.org/10.17221/78/2019-hortsci.

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Light-emitting diodes (LEDs) were used for the spring greenhouse cultivation of eggplant (Solanum melongena L.) ‘Milar F1’ and tomato (S. lycopersicon L.) ‘Benito F1’ transplants. Seedlings were grown under natural light conditions with the supplemental LED light. A 16-h photoperiod provided plants with a DLI of 12.6 (eggplant) and 9.6 (tomato) mol m2/day. Four supplemental light spectra were tested: L1 (90% red + 10% blue); L2 (80% red + 20% blue); L3 (43% red + 42% blue+15% green) and L4 (56% red + 26% blue + 15% green + 3% UV-A). The PPFD in each LED light treatment was 150 ± 20 µmol/m2·s. Compared to the control plants (without LED lighting), the eggplant transplants had about a 25% larger leaf area and a higher level of total phenol content as well as a higher antiradical scavenging activity under the L1 spectrum. The favourable spectrum for the tomato transplants consisted of red to blue in a ratio of 1 : 1 mixed with a green light (L3) – the leaves were characterised by a higher content of dry matter, soluble sugars, photosynthetic pigments and total phenols; also the radical scavenging activity increased in comparison to the control group. It was shown that the supplemental irradiation of transplants was economically acceptable.

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Kobayashi, Haruna, and Yohei Kurata. "Relationship between photomorphogenesis and tree growth in Cryptomeria japonica assessed using light emitting diodes." BioResources 17, no. 1 (December 21, 2021): 1136–43. http://dx.doi.org/10.15376/biores.17.1.1136-1143.

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Recently, there has been considerable interest in establishing tree-rearing methods for breeding nursery trees, which are similar to the methods employed in plant factories to produce vegetables. Studies have shown that the efficiency of tree cultivation can be improved by changing the wavelength of the lighting that is used to raise young plants and that light emitting diodes (LEDs) are effective for this purpose. In this study, the effect of blue (450 nm), red (660 nm), and white (combination of blue and yellow (525 nm) LED lights was investigated for rearing Cryptomeria japonica saplings. 7 saplings with each LED were prepared and reared for 52 weeks in a constant environment chamber (Temperature: 23 ± 2 °C, relative humidity 50% ± 10%), and their growth rates and root system morphology were compared. After 52 weeks of breeding, red light induced slightly more stem growth than white light. Blue light was nearly three times more effective in stem growth than white light. Furthermore, the wavelength of light affected the root system morphology. Many root branches were observed in saplings reared under red light, while marked taproot growth was observed in saplings reared under blue light. There was a possibility that saplings could be produced more efficiently by using LED.

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Morańska, Emilia, Magdalena Simlat, Marzena Warchoł, Edyta Skrzypek, Piotr Waligórski, Dominique Laurain-Mattar, Rosella Spina, and Agata Ptak. "Phenolic Acids and Amaryllidaceae Alkaloids Profiles in Leucojum aestivum L. In Vitro Plants Grown under Different Light Conditions." Molecules 28, no. 4 (February 4, 2023): 1525. http://dx.doi.org/10.3390/molecules28041525.

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Light-emitting diodes (LEDs) have emerged as efficient light sources for promoting in vitro plant growth and primary and secondary metabolite biosynthesis. This study investigated the effects of blue, red, and white-red LED lights on plant biomass growth, photosynthetic pigments, soluble sugars, phenolic compounds, the production of Amaryllidaceae alkaloids, and the activities of antioxidant enzymes in Leucojum aestivum L. cultures. A white fluorescent light was used as a control. The plants that were grown under white-red and red light showed the highest fresh biomass increments. The blue light stimulated chlorophyll a, carotenoid, and flavonoid production. The white-red and blue lights were favourable for phenolic acid biosynthesis. Chlorogenic, p-hydroxybenzoic, caffeic, syringic, p-coumaric, ferulic, sinapic, and benzoic acids were identified in plant materials, with ferulic acid dominating. The blue light had a significant beneficial effect both on galanthamine (4.67 µg/g of dry weight (DW)) and lycorine (115 µg/g DW) biosynthesis. Red light treatment increased catalase and superoxide dismutase activities, and high catalase activity was also observed in plants treated with white-red and blue light. This is the first report to provide evidence of the effects of LED light on the biosynthesis of phenolic acid and Amaryllidaceae alkaloids in L. aestivum cultures, which is of pharmacological importance and can propose new strategies for their production.

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Ridhani, Fatahah Dwi, Nur Hasanah Ahniar, Ansor Ibrahim Usman, Moch Prastawa Assalim Tetra Putra, and Suharyati Atmadja. "The Design of Infant Warmer with Simple Blue Light Therapy LED Addition." SANITAS: Jurnal Teknologi dan Seni Kesehatan 13, no. 1 (June 28, 2022): 44–55. http://dx.doi.org/10.36525/sanitas.2022.5.

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This paper presents a result of experiment on adding built-in blue light therapy on a purpose built infant warmer. Blue light therapy are often used in case of jaundice and usually a separated unit with added complexity. The blue light assembly was LED based that placed along the heater bar, placed on its aluminum strips and spaced to prevent being affected by the heater. Blue light LED specification was an SMD 5730 dimension with 465nm wavelength driven at 160mA at 12V for the three clusters of LED. Measured light output was around 618-716 lux and measured at the bed area with good uniformity for area under the heater bar at around 60-69 lux. There was another bottom blue LED source but the effect was negligible. The system uses a 10A maximum current source of 12V power supply exclusively for the LED arrangement and another 3A maximum current source of 5V power supply for supplying the rest of the control systems. The LED was controlled by a switch button and monitored for its activation by means of measuring the voltage difference with resistor circuits through the button switch. It works as intended.

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Mohammadian, Farough, Ahmad Mehri, Kamaladdin Abedi, Hossein Ebrahimi, Fereydoon Laal, and Hamed Falahi. "A Simplified Approach to Evaluate Retinal Blue Light Hazard Using the Correlated Color Temperature of LED Light Sources." Journal of Advances in Environmental Health Research 9, no. 4 (October 1, 2121): 299–310. http://dx.doi.org/10.32598/jaehr.9.4.1226.

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Background: Visible light of short wavelength (blue light) can damage the retina cells, called blue light hazard. To protect the retina, permissible exposure limits have been determined by ICNIRP (the International Commission on Non-Ionizing Radiation Protection) and other health and safety agencies. These limits include complex physical concepts, and their evaluation requires light measuring instruments equipped with a blue light hazard function filter, which is not available at the moment in developing countries. This study aims to assess retinal blue light hazard using the correlated color temperature of Light-Emitting Diode (LED) light sources. Methods: In this study, a new method was proposed for evaluating the retinal blue light hazard using only the Correlated Color Temperature (CCL) of LED light sources for which concern on blue light hazard has currently been reinforced. In the proposed method, the radiometric quantity (blue light effective radiance) in W.m-2.sr-1 was converted to the corresponding photometric quantity (blue light effective luminance) in lm.m-2.sr-1. Then a computer code was developed for relevant calculations. Results: The estimated permissible exposure times applying the new photometry approach were highly reliable and supported by the literature. The proposed method is particularly useful because it eliminates the need to utilize any light measuring device. Conclusion: The new approach makes the concept of blue light hazard straightforward and understandable for all specialists dealing with optical radiation safety.

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Cooper, Keith. "LED streetlights responsible for blue-light pollution in Europe." Physics World 35, no. 11 (December 1, 2022): 6i. http://dx.doi.org/10.1088/2058-7058/35/11/06.

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Leoni, B., O. D. Palmitessa, F. Serio, A. Signore, and P. Santamaria. "Blue LED light irradiation enhances yield in green beans." Acta Horticulturae, no. 1321 (September 2021): 9–14. http://dx.doi.org/10.17660/actahortic.2021.1321.2.

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Itoh, Akitoshi, and Hirotomo Hisama. "Motion Control of Daphnia magna by Blue LED Light." Journal of Aero Aqua Bio-mechanisms 1, no. 1 (2010): 93–98. http://dx.doi.org/10.5226/jabmech.1.93.

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Journal articles on the topic 'Blue LED light'

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