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Author Kayaba, M.; Iwayama, K.; Ogata, H.; Seya, Y.; Tokuyama, K.; Satoh, M. url  doi
openurl 
  Title Drowsiness and low energy metabolism in the following morning induced by nocturnal blue light exposure Type Journal Article
  Year 2013 Publication Sleep Medicine Abbreviated Journal Sleep Medicine  
  Volume 14 Issue Pages e166-e167  
  Keywords (up) blue light; light exposure; light at night; circadian disruption; drowsiness; melatonin; metabolism; sleep  
  Abstract Introduction

Evening light exposure debilitates the circadian rhythm and elicits sleep disturbance. Blue light peak wavelengths, around 460 nm, suppress melatonin secretion via the non-image-forming system. The effects of nocturnal blue light exposure on sleep have been reported to be specific but rather small (Münch, 2008). This study was designed to assess the effect of nocturnal blue light exposure on sleep and energy metabolism until noon the next day.

Materials and methods

Nine healthy male volunteers aged between 21 and 25 participated in this study which had a balanced cross-over design with intrasubject comparisons. After 2 h dark adaptation, the subjects were exposed to blue light or no light for 2 h. The peak wavelength of the blue LED was 465 nm, and the horizontal irradiance of the blue light at the height of eye was at 7.02fÊW/cm2. Sleep was recorded polysomnographically, and energy metabolism was measured with a whole body indirect calorimeter.

Results

There were no significant differences in sleep architecture and energy metabolism during the night. However, dozing (stages 1 and 2) was significantly higher (26.0 < 29.4 vs 6.3 < 8.1 min, P < 0.05), and energy expenditure, O2 consumption, CO2 production and the thermic effect of food (increase in energy expenditure after breakfast) were significantly lower the following morning in the blue light exposure subjects.

Conclusion

Contrary to our expectation, sleep architecture and energy metabolism during sleep were not affected by evening exposure to blue light. It might be due to our milder intervention by which subjects in a sitting position did not gaze at the light source set on the ceiling, while the subjects in previous studies directly received brighter light via custom built goggles (Cajochen, 2005; Münch, 2008) or gazed at a light source under the influence of mydriatic agents to dilate pupils (Brainard, 2001). New findings of the present study were that dozing (stages 1 and 2) was significantly increased, and energy metabolism was significantly lower the following morning in blue light exposed subjects. This suggests that modulation of the circadian rhythm is affected by nocturnal blue light exposure and the effect continues in the following daytime even if the intervention was mild.
 
  Address University of Tsukuba, Graduate School of Comprehensive Human Sciences, Japan  
  Corporate Author Thesis  
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  Series Volume Series Issue Edition  
  ISSN 1389-9457 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 349  
Permanent link to this record
 

 
Author Haus, E.L.; Smolensky, M.H. url  doi
openurl 
  Title Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation Type Journal Article
  Year 2013 Publication Sleep Medicine Reviews Abbreviated Journal Sleep Med Rev  
  Volume 17 Issue 4 Pages 273-284  
  Keywords (up) Cell Cycle/physiology; Circadian Rhythm/*physiology; Epigenesis, Genetic/physiology; Humans; Light; Melatonin/physiology; Neoplasms/*etiology; Risk Factors; Sleep Deprivation/*complications; Work Schedule Tolerance/*physiology; oncogenesis  
  Abstract Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species.  
  Address Department of Laboratory Medicine & Pathology, University of Minnesota and Health Partners Medical Group, Regions Hospital, 640 Jackson Street, St. Paul, Minnesota 55101, USA. Erhard.X.Haus@HealthPartners.com  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1087-0792 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23137527 Approved no  
  Call Number IDA @ john @ Serial 157  
Permanent link to this record
 

 
Author Saldaña-Vázquez, R.A.; Munguía-Rosas, M.A. url  doi
openurl 
  Title Lunar phobia in bats and its ecological correlates: A meta-analysis Type Journal Article
  Year 2013 Publication Mammalian Biology – Zeitschrift für Säugetierkunde Abbreviated Journal Mammalian Biology – Zeitschrift für Säugetierkunde  
  Volume 78 Issue 3 Pages 216-219  
  Keywords (up) Chiroptera; Foraging activity; Foraging habitat; Latitude; Moonlight; mammals; bats; animals  
  Abstract Animals show several behavioral strategies to reduce predation risks. Presumably, moonlight avoidance is a strategy used by some nocturnal species to reduce the risk of predation. In bats, some research indicates that foraging activity is negatively correlated with moonlight intensity, a phenomenon better known as lunar phobia. However, the currently available evidence is contradictory because some bat species reduce their activity during nights with more moonlight while the opposite occurs in other species. We quantitatively evaluated the strength and direction of the relationship between moonlight intensity and bat activity using a meta-analysis. We also looked at some ecological correlates of lunar phobia in bats. Specifically, we examined foraging habitat and latitude as potential moderators of the size of the lunar phobia effect. Our results show that, regardless of the method used to evaluate bat activity, the overall relationship between moonlight intensity and bat activity is significant and negative (r = &#8722;0.22). Species foraging on the surface of the water (piscivores and insectivores; r = &#8722;0.83) and forest canopy species (i.e., big frugivores; r = &#8722;0.30) are more affected by moonlight than those with different foraging habitats (understory, subcanopy, open air). Latitude was positively correlated with lunar phobia (r = 0.023). The stronger lunar phobia for bats foraging on the water surface and in the forest canopy may suggest that the risk of predation is greater where moonlight penetrates more easily. The significant effect of latitude as a moderator of lunar phobia suggests that there is a weak geographic pattern, with this phobia slightly more common in tropical bats than in temperate species.  
  Address  
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  Series Volume Series Issue Edition  
  ISSN 1616-5047 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 97  
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Author Nguyen, B.P.; Postma, E.; Ekkers, D.; Degener, F.; Mejier, T. url  openurl
  Title Bad Kissingen : a blueprint for future urban design Type Report
  Year 2013 Publication University Groningen Abbreviated Journal  
  Volume Issue Pages  
  Keywords (up) chronobiology, economy, society, urban design  
  Abstract  
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  Notes Approved no  
  Call Number LoNNe @ schroer @ Serial 1061  
Permanent link to this record
 

 
Author Hurley, S.; Nelson, D.O.; Garcia, E.; Gunier, R.; Hertz, A.; Reynolds, P. url  doi
openurl 
  Title A cross-sectional analysis of light at night, neighborhood sociodemographics and urinary 6-sulfatoxymelatonin concentrations: implications for the conduct of health studies Type Journal Article
  Year 2013 Publication International Journal of Health Geographics Abbreviated Journal Int J Health Geogr  
  Volume 12 Issue 1 Pages 39  
  Keywords (up) circadian disruption; 6-sulftoxymelatonin; melatonin; aMT6s, DMSP; light at night  
  Abstract BACKGROUND: There is accumulating evidence that circadian disruption, mediated by alterations in melatonin levels, may play an etiologic role in a wide variety of diseases. The degree to which light-at-night (LAN) and other factors can alter melatonin levels is not well-documented. Our primary objective was to evaluate the degree to which estimates of outdoor environmental LAN predict 6-sulftoxymelatonin (aMT6s), the primary urinary metabolite of melatonin. We also evaluated other potential behavioral, sociodemographic, and anthropomorphic predictors of aMT6s. METHODS: Study participants consisted of 303 members of the California Teachers Study who provided a 24-hour urine specimen and completed a self-administered questionnaire in 2000. Urinary aMT6s was measured using the Buhlmann ELISA. Outdoor LAN levels were estimated from satellite imagery data obtained from the U.S. Defense Meteorological Satellite Program's (DMSP) Operational Linescan System and assigned to study participants' geocoded residential address. Information on other potential predictors of aMT6s was derived from self-administered surveys. Neighborhood socioeconomic status (SES) was based on U.S. Census block group data. RESULTS: Lower aMT6s levels were significantly associated with older age, shorter nights, and residential locations in lower SES neighborhoods. Outdoor sources of LAN estimated using low-dynamic range DMSP data had insufficient variability across urban neighborhoods to evaluate. While high-dynamic range DMSP offered much better variability, it was not significantly associated with urinary aMT6s. CONCLUSIONS: Future health studies should utilize the high-dynamic range DMSP data and should consider other potential sources of circadian disruption associated with living in lower SES neighborhoods.  
  Address  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-072X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24127816; PMCID:PMC3766028 Approved no  
  Call Number IDA @ john @ Serial 142  
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