Records |
Author |
Souman, J.L.; Borra, T.; de Goijer, I.; Schlangen, L.J.M.; Vlaskamp, B.N.S.; Lucassen, M.P. |
Title |
Spectral Tuning of White Light Allows for Strong Reduction in Melatonin Suppression without Changing Illumination Level or Color Temperature |
Type |
Journal Article |
Year |
2018 |
Publication |
Journal of Biological Rhythms |
Abbreviated Journal |
J Biol Rhythms |
Volume |
33 |
Issue |
4 |
Pages |
420-431 |
Keywords |
Human Health; Lighting |
Abstract |
Studies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature. Moreover, it changed the appearance from white light to yellow/orange, rendering it unusable for many practical applications. Here, we show that selectively tuning a polychromatic white light spectrum, compensating for the reduction in spectral power between 450 and 500 nm by enhancing power at even shorter wavelengths, can produce greatly different effects on melatonin production, without changes in illuminance or color temperature. On different evenings, 15 participants were exposed to 3 h of white light with either low or high power between 450 and 500 nm, and the effects on salivary melatonin levels and alertness were compared with those during a dim light baseline. Exposure to the spectrum with low power between 450 and 500 nm, but high power at even shorter wavelengths, did not suppress melatonin compared with dim light, despite a large difference in illuminance (175 vs. <5 lux). In contrast, exposure to the spectrum with high power between 450 and 500 nm (also 175 lux) resulted in almost 50% melatonin suppression. For alertness, no significant differences between the 3 conditions were observed. These results open up new opportunities for lighting applications that allow for the use of electrical lighting without disturbance of melatonin production. |
Address |
Philips Lighting Research, Department Lighting Applications, Eindhoven, The Netherlands |
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English |
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0748-7304 |
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Notes |
PMID:29984614 |
Approved |
no |
Call Number |
GFZ @ kyba @ |
Serial |
1985 |
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Author |
Flores, D.E.F.L.; Oda, G.A. |
Title |
Novel Light/Dark Regimens with Minimum Light Promote Circadian Disruption: Simulations with a Model Oscillator |
Type |
Journal Article |
Year |
2018 |
Publication |
Journal of Biological Rhythms |
Abbreviated Journal |
J Biol Rhythms |
Volume |
in press |
Issue |
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Pages |
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Keywords |
Animals |
Abstract |
Artificial lab manipulation of LD cycles has enabled simulations of the disruptive conditions found in modern human societies, such as jet-lag, night-work and light at night. New techniques using animal models have been developed, and these can greatly improve our understanding of circadian disruption. Some of these techniques, such as in vivo bioluminescence assays, require minimum external light. This requirement is challenging because the usual lighting protocols applied in circadian desynchronization experiments rely on considerable light input. Here, we present a novel LD regimen that can disrupt circadian rhythms with little light per day, based on computer simulations of a model limit-cycle oscillator. The model predicts that a single light pulse per day has the potential to disturb rhythmicity when pulse times are randomly distributed within an interval. Counterintuitively, the rhythm still preserves an underlying 24-h periodicity when this interval is as large as 14 h, indicating that day/night cues are still detectable. Only when pulses are spread throughout the whole 24-h day does the rhythm lose any day-to-day period correlation. In addition, the model also reveals that stronger pulses of brighter light should exacerbate the disrupting effects. We propose the use of this LD schedule-which would be compatible with the requirements of in vivo bioluminescence assays-to help understand circadian disruption and associated illnesses. |
Address |
Instituto de Biociencias, Universidade de Sao Paulo, Sao Paulo, SP, Brazil |
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English |
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ISSN  |
0748-7304 |
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Notes |
PMID:30595077 |
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no |
Call Number |
GFZ @ kyba @ |
Serial |
2146 |
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Author |
Ostrin, L.A. |
Title |
Ocular and systemic melatonin and the influence of light exposure |
Type |
Journal Article |
Year |
2018 |
Publication |
Clinical & Experimental Optometry |
Abbreviated Journal |
Clin Exp Optom |
Volume |
in press |
Issue |
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Pages |
in press |
Keywords |
Vision; Review; Human Health |
Abstract |
Melatonin is a neurohormone known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland is heavily influenced by light stimulation of the retina, particularly through the intrinsically photosensitive retinal ganglion cells. Melatonin is also synthesised within the eye, although to a much lesser extent than in the pineal gland. Melatonin acts directly on ocular structures to mediate a variety of diurnal rhythms and physiological processes within the eye. The interactions between melatonin, the eye, and visual function have been the subject of a considerable body of recent research. This review is intended to provide a broad introduction for eye-care practitioners and researchers to the topic of melatonin and the eye. The first half of the review describes the anatomy and physiology of melatonin production: how visual inputs affect the pineal production of melatonin; how melatonin is involved in a variety of diurnal rhythms within the eye, including photoreceptor disc shedding, neuronal sensitivity, and intraocular pressure control; and melatonin production and physiological roles in retina, ciliary body, lens and cornea. The second half of the review describes clinical implications of light/melatonin interactions. These include light exposure and photoreceptor contributions in melatonin suppression, leading to consideration of how blue blockers, cataract, and light therapy might affect sleep and mood in patients. Additionally, the interactions between melatonin, sleep and refractive error development are discussed. A better understanding of environmental factors that affect melatonin and subsequent effects on physiological processes will allow clinicians to develop treatments and recommend modifiable behaviours to improve sleep, increase daytime alertness, and regulate ocular and systemic processes related to melatonin. |
Address |
University of Houston College of Optometry, Houston, Texas, USA |
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English |
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ISSN  |
0816-4622 |
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Notes |
PMID:30074278 |
Approved |
no |
Call Number |
GFZ @ kyba @ |
Serial |
1986 |
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Author |
Bowne, D.R.; Cosentino, B.J.; Anderson, L.J.; Bloch, C.P.; Cooke, S.; Crumrine, P.W.; Dallas, J.; Doran, A.; Dosch, J.J.; Druckenbrod, D.L.; Durtsche, R.D.; Garneau, D.; Genet, K.S.; Fredericksen, T.S.; Kish, P.A.; Kolozsvary, M.B.; Kuserk, F.T.; Lindquist, E.S.; Mankiewicz, C.; March, J.G.; Muir, T.J.; Murray, K.G.; Santulli, M.N.; Sicignano, F.J.; Smallwood, P.D.; Urban, R.A.; Winnett-Murray, K.; Zimmermann, C.R. |
Title |
Effects of urbanization on the population structure of freshwater turtles across the United States |
Type |
Journal Article |
Year |
2018 |
Publication |
Conservation Biology : the Journal of the Society for Conservation Biology |
Abbreviated Journal |
Conserv Biol |
Volume |
32 |
Issue |
5 |
Pages |
1150-1161 |
Keywords |
Animals; Remote Sensing |
Abstract |
Landscape-scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization. As a collaborative effort of the Ecological Research as Education Network (EREN), we sampled freshwater turtle populations in 11 states across the central and eastern United States. Contrary to expectations, we found a significant positive relationship between proportions of mature female painted turtles (Chrysemys picta) and urbanization. We did not detect a relationship between urbanization and proportions of immature turtles. Urbanization may alter the thermal environment of nesting sites such that more females are produced as urbanization increases. Our approach of creating a collaborative network of scientists and students at undergraduate institutions proved valuable in terms of testing our hypothesis over a large spatial scale while also allowing students to gain hands-on experience in conservation science. This article is protected by copyright. All rights reserved. |
Address |
Department of Biology, Rogers State University, 1701 W. Will Rogers Boulevard, Claremore, OK 74017, U.S.A |
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English |
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Edition |
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ISSN  |
0888-8892 |
ISBN |
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Notes |
PMID:29781169 |
Approved |
no |
Call Number |
GFZ @ kyba @ |
Serial |
1920 |
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Author |
Hüppop, O.; Ciach, M.; Diehl, R.; Reynolds, D.R.; Stepanian, P.M.; Menz, M.H.M. |
Title |
Perspectives and challenges for the use of radar in biological conservation |
Type |
Journal Article |
Year |
2018 |
Publication |
Ecography |
Abbreviated Journal |
Ecography |
Volume |
in press |
Issue |
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Pages |
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Keywords |
Animals; Review |
Abstract |
Radar is at the forefront for the study of broad‐scale aerial movements of birds, bats and insects and related issues in biological conservation. Radar techniques are especially useful for investigating species which fly at high altitudes, in darkness, or which are too small for applying electronic tags. Here, we present an overview of radar applications in biological conservation and highlight its future possibilities. Depending on the type of radar, information can be gathered on local‐ to continental‐scale movements of airborne organisms and their behaviour. Such data can quantify flyway usage, biomass and nutrient transport (bioflow), population sizes, dynamics and distributions, times and dimensions of movements, areas and times of mass emergence and swarming, habitat use and activity ranges. Radar also captures behavioural responses to anthropogenic disturbances, artificial light and man‐made structures. Weather surveillance and other long‐range radar networks allow spatially broad overviews of important stopover areas, songbird mass roosts and emergences from bat caves. Mobile radars, including repurposed marine radars and commercially dedicated ‘bird radars’, offer the ability to track and monitor the local movements of individuals or groups of flying animals. Harmonic radar techniques have been used for tracking short‐range movements of insects and other small animals of conservation interest. However, a major challenge in aeroecology is determining the taxonomic identity of the targets, which often requires ancillary data obtained from other methods. Radar data have become a global source of information on ecosystem structure, composition, services and function and will play an increasing role in the monitoring and conservation of flying animals and threatened habitats worldwide. |
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ISSN  |
0906-7590 |
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no |
Call Number |
GFZ @ kyba @ |
Serial |
2204 |
Permanent link to this record |