| Records |
Author  |
Chamorro, E.; Bonnin-Arias, C.; Perez-Carrasco, M.J.; Munoz de Luna, J.; Vazquez, D.; Sanchez-Ramos, C. |
| Title |
Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro |
Type |
Journal Article |
| Year |
2013 |
Publication |
Photochemistry and Photobiology |
Abbreviated Journal |
Photochem Photobiol |
| Volume |
89 |
Issue |
2 |
Pages |
468-473 |
| Keywords |
Human Health; Apoptosis/*radiation effects; Biological Markers/metabolism; Caspases/metabolism; Cell Survival/radiation effects; DNA Damage; Epithelial Cells/cytology/metabolism/*radiation effects; Histones/metabolism; Humans; Light; Membrane Potential, Mitochondrial/*radiation effects; Mitochondria/*radiation effects; Photoperiod; Primary Cell Culture; Reactive Oxygen Species/metabolism; Retinal Pigment Epithelium/cytology/metabolism/*radiation effects |
| Abstract |
Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC. |
| Address |
Neuro-Computing and Neuro-Robotics Research Group, Universidad Complutense de Madrid, Madrid, Spain. eva.chamorro@opt.ucm.es |
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| Language |
English |
Summary Language |
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| ISSN |
0031-8655 |
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| Notes |
PMID:22989198 |
Approved |
no |
| Call Number |
LoNNe @ christopher.kyba @ |
Serial |
511 |
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| Author |
Chang, A.-M.; Scheer, F.A.J.L.; Czeisler, C.A.; Aeschbach, D. |
| Title |
Direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans depend on prior light history |
Type |
Journal Article |
| Year |
2013 |
Publication |
Sleep |
Abbreviated Journal |
Sleep |
| Volume |
36 |
Issue |
8 |
Pages |
1239-1246 |
| Keywords |
Arousal/*radiation effects; Attention/radiation effects; Cross-Over Studies; *Electroencephalography; Female; Humans; *Light; Male; Melatonin/blood/physiology; Psychomotor Performance/radiation effects; Reaction Time; Wakefulness/*radiation effects; Young Adult; Light history; alertness and performance; light exposure |
| Abstract |
STUDY OBJECTIVES: Light can induce an acute alerting response in humans; however, it is unknown whether the magnitude of this response is simply a function of the absolute illuminance of the light itself, or whether it depends on illuminance history preceding the stimulus. Here, we compared the effects of illuminance history on the alerting response to a subsequent light stimulus. DESIGN: A randomized, crossover design was used to compare the effect of two illuminance histories (1 lux vs. 90 lux) on the alerting response to a 6.5-h 90-lux light stimulus during the biological night. SETTING: Intensive Physiologic Monitoring Unit, Brigham and Women's Hospital, Boston, MA. PARTICIPANTS: Fourteen healthy young adults (6 F; 23.5 +/- 2.9 years). INTERVENTIONS: Participants were administered two 6.5-h light exposures (LE) of 90 lux during the biological night. For 3 days prior to each LE, participants were exposed to either 1 lux or 90 lux during the wake episode. MEASUREMENTS AND RESULTS: The alerting response to light was assessed using subjective sleepiness ratings, lapses of attention, and reaction times as measured with an auditory psychomotor vigilance task, as well as power density in the delta/theta range of the waking EEG. The alerting response to light was greater and lasted longer when the LE followed exposure to 1 lux compared to 90 lux light. CONCLUSION: The magnitude and duration of the alerting effect of light at night depends on the illuminance history and appears to be subject to sensitization and adaptation. |
| Address |
Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. amchang@rics.bwh.harvard.edu |
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English |
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0161-8105 |
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| Notes |
PMID:23904684; PMCID:PMC3700721 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
145 |
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| Author |
Chellappa, S.L.; Steiner, R.; Oelhafen, P.; Lang, D.; Gotz, T.; Krebs, J.; Cajochen, C. |
| Title |
Acute exposure to evening blue-enriched light impacts on human sleep |
Type |
Journal Article |
| Year |
2013 |
Publication |
Journal of Sleep Research |
Abbreviated Journal |
J Sleep Res |
| Volume |
22 |
Issue |
5 |
Pages |
573-580 |
| Keywords |
Human Health |
| Abstract |
Light in the short wavelength range (blue light: 446-483 nm) elicits direct effects on human melatonin secretion, alertness and cognitive performance via non-image-forming photoreceptors. However, the impact of blue-enriched polychromatic light on human sleep architecture and sleep electroencephalographic activity remains fairly unknown. In this study we investigated sleep structure and sleep electroencephalographic characteristics of 30 healthy young participants (16 men, 14 women; age range 20-31 years) following 2 h of evening light exposure to polychromatic light at 6500 K, 2500 K and 3000 K. Sleep structure across the first three non-rapid eye movement non-rapid eye movement – rapid eye movement sleep cycles did not differ significantly with respect to the light conditions. All-night non-rapid eye movement sleep electroencephalographic power density indicated that exposure to light at 6500 K resulted in a tendency for less frontal non-rapid eye movement electroencephalographic power density, compared to light at 2500 K and 3000 K. The dynamics of non-rapid eye movement electroencephalographic slow wave activity (2.0-4.0 Hz), a functional index of homeostatic sleep pressure, were such that slow wave activity was reduced significantly during the first sleep cycle after light at 6500 K compared to light at 2500 K and 3000 K, particularly in the frontal derivation. Our data suggest that exposure to blue-enriched polychromatic light at relatively low room light levels impacts upon homeostatic sleep regulation, as indexed by reduction in frontal slow wave activity during the first non-rapid eye movement episode. |
| Address |
Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland; Cyclotron Research Center, University of Liege, Liege, Belgium |
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English |
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Edition |
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| ISSN |
0962-1105 |
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| Notes |
PMID:23509952 |
Approved |
no |
| Call Number |
GFZ @ kyba @ |
Serial |
2201 |
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| Author |
Cho, J.R.; Joo, E.Y.; Koo, D.L.; Hong, S.B. |
| Title |
Let there be no light: the effect of bedside light on sleep quality and background electroencephalographic rhythms |
Type |
Journal Article |
| Year |
2013 |
Publication |
Sleep Medicine |
Abbreviated Journal |
Sleep Med |
| Volume |
14 |
Issue |
12 |
Pages |
1422-1425 |
| Keywords |
Eeg; Light; Polysomnography; Sleep; Sleep spindle; Slow oscillation |
| Abstract |
OBJECTIVES: Artificial lighting has been beneficial to society, but unnecessary light exposure at night may cause various health problems. We aimed to investigate how whole-night bedside light can affect sleep quality and brain activity. PATIENTS AND METHODS: Ten healthy sleepers underwent two polysomnography (PSG) sessions, one with the lights off and one with the lights on. PSG variables related to sleep quality were extracted and compared between lights-off and lights-on sleep. Spectral analysis was performed to rapid eye movement (REM) sleep and non-REM (NREM) sleep epochs to reveal any light-induced differences in background brain rhythms. RESULTS: Lights-on sleep was associated with increased stage 1 sleep (N1), decreased slow-wave sleep (SWS), and increased arousal index. Spectral analysis revealed that theta power (4-8Hz) during REM sleep and slow oscillation (0.5-1Hz), delta (1-4Hz), and spindle (10-16Hz) power during NREM sleep were decreased in lights-on sleep conditions. CONCLUSIONS: Sleeping with the light on not only causes shallow sleep and frequent arousals but also has a persistent effect on brain oscillations, especially those implicated in sleep depth and stability. Our study demonstrates additional hazardous effect of light pollution on health. |
| Address |
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Samsung Biomedical Research Institute, Seoul, Republic of Korea; Division of Computation and Neural Systems, California Institute of Technology, Pasadena, California, USA |
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English |
Summary Language |
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| ISSN |
1389-9457 |
ISBN |
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| Notes |
PMID:24210607 |
Approved |
no |
| Call Number |
IDA @ john @ |
Serial |
141 |
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| Author |
Ciocca, M.; Wang, J. |
| Title |
By the light of the silvery Moon: fact and fiction |
Type |
Journal Article |
| Year |
2013 |
Publication |
Physics Education |
Abbreviated Journal |
Phys. Educ. |
| Volume |
48 |
Issue |
3 |
Pages |
360-367 |
| Keywords |
Vision; moonlight; Purkinje effect; Purkinje shift; mesopic |
| Abstract |
Is moonlight 'silver' or 'cold'? In this paper we discuss the interesting combination of factors that contribute to the common descriptions of moonlight. Sunlight is reflected from the lunar surface and red-shifted. When traversing the atmosphere, moonlight is further depleted of short wavelength content by Rayleigh scattering. We measured the spectra of the moonlight to show these effects and compared them with sunlight. All measurements, including spectral reflectance, suggest that moonlight is redder than sunlight. The silvery Moon is just an illusion due to the properties and behaviour of our own eyes, including the responses of rods and cones and the physiological perceptive phenomenon called Purkinje shift. |
| Address |
Eastern Kentucky University, Richmond, KY, USA E-mail: marco.ciocca(at)eku.edu |
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IOP |
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English |
Summary Language |
English |
Original Title |
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0031-9120 |
ISBN |
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no |
| Call Number |
IDA @ john @ |
Serial |
2227 |
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