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Author Brelsford, CC; Robson, TM
Title (up) Blue light advances bud burst in branches of three deciduous tree species under short-day conditions Type Journal Article
Year 2018 Publication Trees Abbreviated Journal
Volume 32 Issue 4 Pages 1157-1164
Keywords Plants
Abstract During spring, utilising multiple cues allow tree species from temperate and boreal regions to coordinate their bud burst and leaf out, at the right moment to capitalise on favourable conditions for photosynthesis. Whilst the effect of blue light (400–500 nm) has been shown to increase percentage bud burst of axillary shoots of Rosa sp., the effects of blue light on spring-time bud burst of deciduous tree species have not previously been reported. We tested the hypotheses that blue light would advance spring bud burst in tree species, and that late-successional species would respond more than early-successional species, whose bud burst is primarily determined by temperature. The bud development of Alnus glutinosa, Betula pendula, and Quercus robur branches, cut from dormant trees, was monitored under two light treatments of equal photosynthetically active radiation (PAR, 400–700 nm) and temperature, either with or without blue light, under controlled environmental conditions. In the presence of blue light, the mean time required to reach 50% bud burst was reduced by 3.3 days in Betula pendula, 6 days in Alnus glutinosa, and 6.3 days in Quercus robur. This result highlights the potential of the blue region of the solar spectrum to be used as an extra cue that could help plants to regulate their spring phenology, alongside photoperiod and temperature. Understanding how plants combine photoreceptor-mediated cues with other environmental cues such as temperature to control phenology is essential if we are to accurately predict how tree species might respond to climate change.
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Call Number GFZ @ kyba @ Serial 1847
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Author Kong, Y.; Stasiak, M.; Dixon, M.A.; Zheng, Y.
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 Stern, M.; Broja, M.; Sansone, R.; Grone, M.; Skene, S.S.; Liebmann, J.; Suschek, C.V.; Born, M.; Kelm, M.; Heiss, C.
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)
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Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
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ISSN 2047-4873 ISBN Medium
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Notes PMID:30196723 Approved no
Call Number IDA @ john @ Serial 2157
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Author Point, S.
Title (up) Blue Light Hazard: are exposure limit values protective enough for newborn infants? Type Journal Article
Year 2018 Publication Radioprotection Abbreviated Journal
Volume 53 Issue 3 Pages 219-224
Keywords Human Health
Abstract Blue Light Hazard is an emerging concern for health of population. Nevertheless, acute exposure to blue rays from artificial light is well taken into account by normative requirements applicable to lamps engineering and risk for general population is low. There is also no evidence for a chronic effect of artificial lighting on retina for general population at radiance below exposure limit values. That said, children in the very first years of life constitute a specific population to consider. On one side, eye anatomy of very young infants is different from elder young people or adults. On the other side, infants can be in close contact with some luminous toys or night lights. This paper presents a first approach for taking into account the specific anatomy of newborn infants’ eyes in blue light hazard evaluation. Results show that differences of crystalline lens transparency, focal length and pupil diameter could induce a significantly higher retinal exposure than for adult.
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Call Number GFZ @ kyba @ Serial 1982
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Author Griepentrog, J.E.; Labiner, H.E.; Gunn, S.R.; Rosengart, M.R.
Title (up) Bright environmental light improves the sleepiness of nightshift ICU nurses Type Journal Article
Year 2018 Publication Critical Care (London, England) Abbreviated Journal Crit Care
Volume 22 Issue 1 Pages 295
Keywords Circadian; Light; Night shift; Nurse; Shift work sleep disorder
Abstract BACKGROUND: Shift work can disturb circadian homeostasis and result in fatigue, excessive sleepiness, and reduced quality of life. Light therapy has been shown to impart positive effects in night shift workers. We sought to determine whether or not prolonged exposure to bright light during a night shift reduces sleepiness and enhances psychomotor performance among ICU nurses.

METHODS: This is a single-center randomized, crossover clinical trial at a surgical trauma ICU. ICU nurses working a night shift were exposed to a 10-h period of high illuminance (1500-2000 lx) white light compared to standard ambient fluorescent lighting of the hospital. They then completed the Stanford Sleepiness Scale and the Psychomotor Vigilance Test. The primary and secondary endpoints were analyzed using the paired t test. A p value <0.05 was considered significant.

RESULTS: A total of 43 matched pairs completed both lighting exposures and were analyzed. When exposed to high illuminance lighting subjects experienced reduced sleepiness scores on the Stanford Sleepiness Scale than when exposed to standard hospital lighting: mean (sem) 2.6 (0.2) vs. 3.0 (0.2), p = 0.03. However, they committed more psychomotor errors: 2.3 (0.2) vs. 1.7 (0.2), p = 0.03.

CONCLUSIONS: A bright lighting environment for ICU nurses working the night shift reduces sleepiness but increases the number of psychomotor errors.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT03331822 . Retrospectively registered on 6 November 2017.
Address Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA. rosengartmr@upmc.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1364-8535 ISBN Medium
Area Expedition Conference
Notes PMID:30424793 Approved no
Call Number GFZ @ kyba @ Serial 2070
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