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Author (down) Zukauskas, A.; Vaicekauskas, R.; Vitta, P.
Title Optimization of solid-state lamps for photobiologically friendly mesopic lighting Type Journal Article
Year 2012 Publication Applied Optics Abbreviated Journal Appl Opt
Volume 51 Issue 35 Pages 8423-8432
Keywords Lighting Systems; Circadian Rhythm; Color; Equipment Design; Humans; Light; *Lighting; Melatonin/metabolism; Photobiology/*methods; Semiconductors; Time Factors; Vision, Ocular
Abstract The circadian and visual-performance-based mesopic systems of photometry were applied for the optimization of the spectral power distributions (SPDs) of the solid-state sources of light for low-illuminance lighting applications. At mesopic adaptation luminances typical of outdoor lighting (0.1-2 cd/m(2)), the optimal SPDs were obtained through the minimization of the mesopic circadian action factor, which is the ratio of the circadian efficacy of radiation to mesopic luminous efficacy of radiation. For correlated color temperatures below ~3000 K, the optimized dichromatic light-emitting diodes (LEDs) are shown to pose a lower circadian hazard than high-pressure sodium lamps and common warm white LEDs; also they are potentially more efficacious and have acceptable color rendition properties under mesopic conditions.
Address Institute of Applied Research, Vilnius University, Sauletekio al. 9-III, Vilnius LT-10222, Lithuania. arturas.zukauskas@ff.vu.lt
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6935 ISBN Medium
Area Expedition Conference
Notes PMID:23262538 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 448
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Author (down) Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D.
Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 16 Pages 1554-1558
Keywords Human Health; Adult; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight; Young Adult; Circadian Rhythm
Abstract The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks.
Address Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309-0354, USA. kenneth.wright@colorado.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:23910656; PMCID:PMC4020279 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 505
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Author (down) Wanvik, P.O.
Title Effects of road lighting: an analysis based on Dutch accident statistics 1987-2006 Type Journal Article
Year 2009 Publication Accident; Analysis and Prevention Abbreviated Journal Accid Anal Prev
Volume 41 Issue 1 Pages 123-128
Keywords Accidents, Traffic/*statistics & numerical data; Automobile Driving/*statistics & numerical data; Confidence Intervals; Cross-Sectional Studies; Humans; *Lighting; Netherlands; Odds Ratio; Risk Factors; Safety; *Visual Fields
Abstract This study estimates the safety effect of road lighting on accidents in darkness on Dutch roads, using data from an interactive database containing 763,000 injury accidents and 3.3 million property damage accidents covering the period 1987-2006. Two estimators of effect are used, and the results are combined by applying techniques of meta-analysis. Injury accidents are reduced by 50%. This effect is larger than the effects found in most of the earlier studies. The effect on fatal accidents is slightly larger than the effect on injury accidents. The effect during twilight is about 2/3 of the effect in darkness. The effect of road lighting is significantly smaller during adverse weather and road surface conditions than during fine conditions. The effects on pedestrian, bicycle and moped accidents are significantly larger than the effects on automobile and motorcycle accidents. The risk of injury accidents was found to increase in darkness. The average increase in risk was estimated to 17% on lit rural roads and 145% on unlit rural roads. The average increase in risk during rainy conditions is about 50% on lit rural roads and about 190% on unlit rural roads. The average increase in risk with respect to pedestrian accidents is about 140% on lit rural roads and about 360% on unlit rural roads.
Address Norwegian Public Roads Administration, Region South, Serviceboks 723, 4808 Arendal, Norway. per.wanvik@vegvesen.no
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-4575 ISBN Medium
Area Expedition Conference
Notes PMID:19114146 Approved no
Call Number IDA @ john @ Serial 250
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Author (down) Vetter, C.; Juda, M.; Lang, D.; Wojtysiak, A.; Roenneberg, T.
Title Blue-enriched office light competes with natural light as a zeitgeber Type Journal Article
Year 2011 Publication Scandinavian Journal of Work, Environment & Health Abbreviated Journal Scand J Work Environ Health
Volume 37 Issue 5 Pages 437-445
Keywords *Circadian Rhythm; *Color; Humans; *Lighting; *Occupational Health; Sleep; Wakefulness; blue light; circadian disruption; Circadian rhythm; sleep
Abstract OBJECTIVES: Circadian regulation of human physiology and behavior (eg, body temperature or sleep-timing), depends on the “zeitgeber” light that synchronizes them to the 24-hour day. This study investigated the effect of changing light temperature at the workplace from 4000 Kelvin (K) to 8000 K on sleep-wake and activity-rest behavior. METHODS: An experimental group (N=27) that experienced the light change was compared with a non-intervention group (N=27) that remained in the 4000 K environment throughout the 5-week study period (14 January to 17 February). Sleep logs and actimetry continuously assessed sleep-wake behavior and activity patterns. RESULTS: Over the study period, the timing of sleep and activity on free days steadily advanced parallel to the seasonal progression of sunrise in the non-intervention group. In contrast, the temporal pattern of sleep and activity in the experimental group remained associated with the constant onset of work. CONCLUSION: The results suggest that artificial blue-enriched light competes with natural light as a zeitgeber. While subjects working under the warmer light (4000 K) appear to entrain (or synchronize) to natural dawn, the subjects who were exposed to blue-enriched (8000 K) light appear to entrain to office hours. The results confirm that light is the dominant zeitgeber for the human clock and that its efficacy depends on spectral composition. The results also indicate that blue-enriched artificial light is a potent zeitgeber that has to be used with diligence.
Address Institute for Medical Psychology, Centre of Chronobiology, Ludwig-Maximilians-Universitat, Munich, Germany
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0355-3140 ISBN Medium
Area Expedition Conference
Notes PMID:21246176 Approved no
Call Number IDA @ john @ Serial 350
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Author (down) Stevens, R.G.; Blask, D.E.; Brainard, G.C.; Hansen, J.; Lockley, S.W.; Provencio, I.; Rea, M.S.; Reinlib, L.
Title Meeting report: the role of environmental lighting and circadian disruption in cancer and other diseases Type Journal Article
Year 2007 Publication Environmental Health Perspectives Abbreviated Journal Environ Health Perspect
Volume 115 Issue 9 Pages 1357-1362
Keywords Human Health; Animals; *Circadian Rhythm; Environmental Exposure; Humans; *Lighting/adverse effects; *Neoplasms/etiology; Research; breast cancer; circadian rhythms; clock genes; lighting; melatonin; phototransduction; pineal gland
Abstract Light, including artificial light, has a range of effects on human physiology and behavior and can therefore alter human physiology when inappropriately timed. One example of potential light-induced disruption is the effect of light on circadian organization, including the production of several hormone rhythms. Changes in light-dark exposure (e.g., by nonday occupation or transmeridian travel) shift the timing of the circadian system such that internal rhythms can become desynchronized from both the external environment and internally with each other, impairing our ability to sleep and wake at the appropriate times and compromising physiologic and metabolic processes. Light can also have direct acute effects on neuroendocrine systems, for example, in suppressing melatonin synthesis or elevating cortisol production that may have untoward long-term consequences. For these reasons, the National Institute of Environmental Health Sciences convened a workshop of a diverse group of scientists to consider how best to conduct research on possible connections between lighting and health. According to the participants in the workshop, there are three broad areas of research effort that need to be addressed. First are the basic biophysical and molecular genetic mechanisms for phototransduction for circadian, neuroendocrine, and neurobehavioral regulation. Second are the possible physiologic consequences of disrupting these circadian regulatory processes such as on hormone production, particularly melatonin, and normal and neoplastic tissue growth dynamics. Third are effects of light-induced physiologic disruption on disease occurrence and prognosis, and how prevention and treatment could be improved by application of this knowledge.
Address Department of Community Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030-6325, USA. bugs@uchc.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0091-6765 ISBN Medium
Area Expedition Conference
Notes PMID:17805428; PMCID:PMC1964886 Approved no
Call Number LoNNe @ kagoburian @ Serial 821
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