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Author Mortazavi, S.A.R., Parhoodeh, S., Hosseini, M.A., Arabi, H., Malakooti, H., Nematollahi, S., Mortazavi, G., Darvish, L., Mortazavi, S.M.J. url  doi
openurl 
  Title (up) Blocking Short-Wavelength Component of the Visible Light Emitted by Smartphones’ Screens Improves Human Sleep Quality Type Journal Article
  Year 2018 Publication Journal of Biomedical Physics and Engineering Abbreviated Journal  
  Volume 8 Issue 4 Pages 375-380  
  Keywords Human Health  
  Abstract Background: It has been shown that short-wavelength blue component of the visible light spectrum can alter the circadian rhythm and suppress the level of melatonin hormone. The short-wavelength light emitted by smartphones’ screens can affect the sleep quality of the people who use these devices at night through suppression of melatonin.

Objectives: In this study, we examined the effects of covering the screens of smartphones with different filters (changing the effective wavelength of the light) on sleep delay time in 43 healthy students.

Materials and Methods: Volunteer students were asked to go to bed at 23:00 and to use their mobile phones in bed for watching a natural life documentary movie for 60 minutes. No filter was used for one night while amber and blue filters were used for other 2 nights. Photospectrometry method was used to determine the output spectrum of the light passing through the filters used for covering the screens of the mobile phones. The order for utilizing amber or blue filters or using no filter was selected randomly. After 1 hour, the participants were asked to record their sleep delay time measured by a modified form of sleep time record sheet.

Results: The mean sleep delay time for the “no-filter” night was 20.84±9.15 minutes, while the sleep delay times for the nights with amber and blue filters were 15.26±1.04 and 26.33±1.59 minutes, respectively.

Conclusion: The findings obtained in this study support this hypothesis that blue light possibly suppresses the secretion of melatonin more than the longer wavelengths of the visible light spectrum. Using amber filter in this study significantly improved the sleep quality. Altogether, these findings lead us to this conclusion that blocking the short-wavelength component of the light emitted by smartphones’ screens improves human sleep.
 
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  Call Number NC @ ehyde3 @ Serial 2077  
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Author Kong, Y.; Stasiak, M.; Dixon, M.A.; Zheng, Y. url  doi
openurl 
  Title (up) Blue light associated with low phytochrome activity can promote elongation growth as shade-avoidance response: A comparison with red light in four bedding plant species Type Journal Article
  Year 2018 Publication Environmental and Experimental Botany Abbreviated Journal Environmental and Experimental Botany  
  Volume 155 Issue Pages 345-359  
  Keywords Plants  
  Abstract o explore the action mode of blue light on elongation growth of bedding plants, the plant growth and morphology traits of petunia (Petunia × hybrida, ‘Duvet Red’), calibrachoa (Calibrachoa × hybrida, ‘Kabloom Deep Blue’), geranium (Pelargonium × hortorum, ‘Pinto Premium Salmon’), and marigold (Tagetes erecta, ‘Antigua Orange’) were compared under four light quality treatments: (1) R, “pure” red light (660 nm); (2) B, “pure” blue light (450 nm); (3) BR, “unpure” blue light created by mixing B with a low level of R to provide B/R ≈ 9; (4) BRF, “unpure” blue light created by adding a low level of far red light to BR with red/far red ≈ 1. Continuous (24-h) light-emitting diode lighting with either 100 or 50 μmol m−2 s−1 photosynthetic photon flux density at ≈ 23℃ was used with the above treatments. After 14–20 day of lighting treatment, B promoted elongation growth compared to R, as demonstrated by a greater canopy height, main stem length, internode length, and daily main stem extension rate. However, BR showed similar or inhibitory effects on these traits relative to R, while BRF exhibited similar promotion effects as B. The calculated phytochrome photoequilibrium, an indication of phytochrome activity, was higher for R (0.89) and BR (0.74) than for B (0.49) and BRF (0.63). Adding red (or far red) light reversed the effects of B (or BR) on elongation growth and the phytochrome photoequilibrium, suggesting that blue light promotion of elongation growth is related to the lower phytochrome activity. Also, B and BRF, when compared to R or BR, promoted elongation growth to a greater degree at 50 than 100 μmol m−2 s−1 for petunia and calibrachoa. In addition to the promoted elongation growth, B and BRF reduced side branch number, biomass allocation to side branches, leaf epinasty, leaf angle, and/or leaf chlorophyll content relative to R or BR, but increased individual leaf area, petiole length, and/or biomass allocation to main stem, which varied with different species. It suggests that the promoted elongation growth by blue light associated with lower phytochrome activity is one of shade-avoidance responses with varying sensitivity among species.  
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  ISSN 0098-8472 ISBN Medium  
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  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 1973  
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Author Zhao, X.; Zhang M.; Che, X.; Zou, F. url  doi
openurl 
  Title (up) Blue light attracts nocturnally migrating birds Type Journal Article
  Year 2020 Publication The Condor Abbreviated Journal  
  Volume in press Issue Pages in press  
  Keywords Animals  
  Abstract Light pollution is increasing and artificial light sources have great impacts on animals. For migrating birds, collisions caused by artificial light pollution are a significant source of mortality. Laboratory studies have demonstrated that birds have different visual sensitivities to different colors of light, but few field experiments have compared birds’ responses to light of different wavelengths. We used 3 monochromatic lights (red, green, and blue) and polychromatic yellow light to study the impact of wavelength on phototaxis at 2 gathering sites of nocturnally migrating birds in Southwest China. For both sites, short-wavelength blue light caused the strongest phototactic response. In contrast, birds were rarely attracted to long-wavelength red light. The attractive effect of blue light was greatest during nights with fog and headwinds. As rapid urbanization and industrialization cause an increase in artificial light, we suggest that switching to longer wavelength lights is a convenient and economically effective way to reduce bird collisions.

摘要

目前地球上光污染日益严重,五颜六色的人工光源对生态系统造成了很大影响。就鸟类而言,在世界各地已发生了很多鸟类撞击人工光源的事件。实验室研究表明,鸟类对不同颜色的光有不同的视觉敏感度,但很少有野外实验比较鸟类对不同波长光的反应。我们在中国西南地区的两个夜间候鸟迁徙聚集点使用三种单色光(红、绿、蓝)和一种复合光(黄),研究了光波长对的候鸟趋光性的影响。研究表明,短波长的蓝光引起了候鸟最强烈的趋光性反应。相反,鸟类很少被长波长的红光所吸引。特别是在有雾和逆风的夜晚,蓝光的吸引力最大。由于快速的城市化和工业化导致人造光的增加,我们认为使用长波光是一个减少鸟类碰撞光源的方便和经济有效的方式。
 
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  Call Number GFZ @ kyba @ Serial 2896  
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Author Dong, K.; Goyarts, E.C.; Pelle, E.; Trivero, J.; Pernodet, N. url  doi
openurl 
  Title (up) Blue Light disrupts the circadian rhythm and create damage in skin cells Type Journal Article
  Year 2019 Publication International Journal of Cosmetic Science Abbreviated Journal Int J Cosmet Sci  
  Volume 41 Issue 6 Pages 558-562  
  Keywords Human Health; Circadian disruption; Skin; Clock genes  
  Abstract On a daily basis, the skin is exposed to many environmental stressors and insults. Over a 24-hr natural cycle, during the day, the skin is focused on protection; while at night, the skin is focused on repairing damage that occurred during daytime and getting ready for the next morning. Circadian rhythm provides the precise timing mechanism for engaging those different pathways necessary to keep a healthy skin through clock genes that are present in all skin cells. The strongest clue for determining cellular functions timing is through sensing light or absence of light (darkness). Here, we asked the question if blue light could be a direct entrainment signal to skin cells and also disrupt their circadian rhythm at night. Through a reporter assay for per1 transcription, we demonstrate that blue light at 410nm decreases per1 transcription in keratinocytes, showing that epidermal skin cells can sense light directly and control their own clock gene expression. This triggers cells to “think” it is daytime even at nighttime. Elsewhere, we measured different skin cell damage due to blue light exposure (at different doses and times of exposure) versus cells that were kept in full darkness. We show an increase of ROS production, DNA damage and inflammatory mediators. These deleterious effects can potentially increase overall skin damage over time and ultimately accelerates aging.  
  Address Materials Science & Engineering, Stony Brook University, Stony Brook  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0142-5463 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31418890 Approved no  
  Call Number GFZ @ kyba @ Serial 2618  
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Author Stern, M.; Broja, M.; Sansone, R.; Grone, M.; Skene, S.S.; Liebmann, J.; Suschek, C.V.; Born, M.; Kelm, M.; Heiss, C. url  doi
openurl 
  Title (up) Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans Type Journal Article
  Year 2018 Publication European Journal of Preventive Cardiology Abbreviated Journal Eur J Prev Cardiol  
  Volume 25 Issue 17 Pages 1875-1883  
  Keywords Human Health; Blue light; blood pressure; endothelial function; forearm blood flow; pulse wave velocity  
  Abstract AIMS: Previous studies have shown that ultraviolet light can lead to the release of nitric oxide from the skin and decrease blood pressure. In contrast to visible light the local application of ultraviolet light bears a cancerogenic risk. Here, we investigated whether whole body exposure to visible blue light can also decrease blood pressure and increase endothelial function in healthy subjects. METHODS: In a randomised crossover study, 14 healthy male subjects were exposed on 2 days to monochromatic blue light or blue light with a filter foil (control light) over 30 minutes. We measured blood pressure (primary endpoint), heart rate, forearm vascular resistance, forearm blood flow, endothelial function (flow-mediated dilation), pulse wave velocity and plasma nitric oxide species, nitrite and nitroso compounds (secondary endpoints) during and up to 2 hours after exposure. RESULTS: Blue light exposure significantly decreased systolic blood pressure and increased heart rate as compared to control. In parallel, blue light significantly increased forearm blood flow, flow-mediated dilation, circulating nitric oxide species and nitroso compounds while it decreased forearm vascular resistance and pulse wave velocity. CONCLUSION: Whole body irradiation with visible blue light at real world doses improves blood pressure, endothelial function and arterial stiffness by nitric oxide released from photolabile intracutanous nitric oxide metabolites into circulating blood.  
  Address Department of Clinical and Experimental Medicine, Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford GU2 7XH, UK. Email: c.heiss(at)  
  Corporate Author Thesis  
  Publisher SAGE Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2047-4873 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30196723 Approved no  
  Call Number IDA @ john @ Serial 2157  
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