scholarly journals Accuracy of the GENEActiv Device for Measuring Light Exposure in Sleep and Circadian Research

2020 ◽  
Vol 2 (2) ◽  
pp. 143-152
Author(s):  
Julia E. Stone ◽  
Elise M. McGlashan ◽  
Elise R. Facer-Childs ◽  
Sean W. Cain ◽  
Andrew J. K. Phillips
Keyword(s):  
Light Source ◽  
Light Exposure ◽  
Red Light ◽  
Spectral Composition ◽  
Green Light ◽  
Well Being ◽  
Infrared Light ◽  
Light Sources ◽  
Lower Accuracy ◽  
The Impact

Light is a variable of key interest in circadian rhythms research, commonly measured using wrist-worn sensors. The GENEActiv Original is a cost-effective and practical option for assessing light in ambulatory settings. With increasing research on health and well-being incorporating sleep and circadian factors, the validity of wearable devices for assessing light environments needs to be evaluated. In this study, we tested the accuracy of the GENEActiv Original devices (n = 10) for recording light under a range of ecologically relevant lighting conditions, including LED, fluorescent, infrared, and outdoor lighting. The GENEActiv output had a strong linear relationship with photopic illuminance. However, the devices consistently under-reported photopic illuminance, especially below 100 lux. Accuracy below 100 lux depended on the light source, with lower accuracy and higher variability under fluorescent lighting. The device’s accuracy was also tested using light sources of varying spectral composition, which indicated that the device tends to under-report photopic illuminance for green light sources and over-report for red light sources. Furthermore, measures of photopic illuminance were impacted by infrared light exposure. We conclude that the GENEActiv Original is suitable for mapping light patterns within an individual context, and can reasonably differentiate indoor vs. outdoor lighting, though the accuracy is variable at low light conditions. Given the human circadian system’s high sensitivity to light levels below 100 lux, if using the GENEActiv Original, we recommend also collecting light source data to better understand the impact on the circadian system, especially where participants spend prolonged periods in dim lighting.

Safest light in a combat area while performing intravenous access in the dark

2018 ◽  
Vol 164 (5) ◽  
pp. 343-346 ◽  
Author(s):  
Attila Aydin ◽  
S Bilge ◽  
M Eryilmaz
Keyword(s):  
Light Source ◽  
Blue Light ◽  
Green Light ◽  
Night Vision ◽  
Infrared Light ◽  
Light Sources ◽  
Night Time ◽  
Naked Eye ◽  
Prehospital Management ◽  
Dark Room

IntroductionCannulation for the administration of intravenous fluids is integral to the prehospital management of injured military patients. However, this may be technically challenging to undertake during night-time conditions where the use of light to aid cannulation may give the tactical situation away to opponents. The aim of this study was to investigate the success and tactical safety of venepuncture under battlefield conditions with different colour light sources.MethodThe procedure was carried out with naked eye in a bright room in the absence of a separate light source, with a naked eye in a dark room under red, white, blue and green light sources and under an infrared light source while wearing night vision goggles (NVGs). The success, safety, degree of difficulty and completion time for each procedure were then explored.ResultsAll interventions made in daylight and in a dark room were found to be 100% successful. Interventions performed under infrared light while wearing NVGs took longer than under other light sources or in daylight. Interventions performed under blue light were tactically safer when compared with interventions performed under different light sources.ConclusionBlue light offered the best tactical safety during intravenous cannulation under night-time conditions and is recommended for future use in tactical casualty care. The use of NVGs using infrared light cannot be recommended if there is the possibility of opponents having access to the technology.

Effect of photoselective filters on the physical and chemical traits of vine-ripened tomato fruits

2005 ◽  
Vol 85 (2) ◽  
pp. 439-446 ◽  
Author(s):  
Hélène Gautier ◽  
Aline Rocci ◽  
Michel Buret ◽  
Dominique Grasselly ◽  
Yvon Dumas ◽  
...  
Keyword(s):  
Vitamin C ◽  
Fruit Ripening ◽  
Light Exposure ◽  
Soluble Sugars ◽  
Red Light ◽  
Spectral Composition ◽  
Titratable Acidity ◽  
Infrared Light ◽  
Tomato Fruits ◽  
Β Carotene

The effects of several wavelength selective light filters placed on developing mature green tomato fruits were studied to determine whether light environment during fruit ripening has an impact on fruit composition. Juice titratable acidity and fruit fresh and dry weight varied little with the different filters. Reducing the red/far-red light ratio with a green filter to simulate vegetation shade slightly delayed ripening. Reducing infrared light (700-1100 nm) reduced vitamin C and soluble sugars content. A drastic reduction in photosynthetic light (97%) reduced both β-carotene (-23%) and lycopene (-29%) contents and red coloration (-21%). Significant correlations were found among the content of soluble sugars, vitamin C and lycopene, but these components increased differently according to the spectral composition of the light transmitted to the fruit. The content of lycopene and β-carotene increased with exposure to photosynthetic radiation and more precisely with exposure to blue light. In contrast, the content of vitamin C and sugar increased with infrared light exposure. Key words: β-carotene, photoselective filters or shading, fruit ripening, fruit environment, lycopene, Lycopersicon esculentum, tomato, vitamin C

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

scholarly journals A conceptual simulation workflow to guide design decisions regarding the effects of daylight on occupants’ alertness

2021 ◽  
Vol 2042 (1) ◽  
pp. 012116
Author(s):  
Pierson Clotilde ◽  
Soto Magán Victoria Eugenia ◽  
Aarts Mariëlle ◽  
Andersen Marilyne
Keyword(s):  
Light Exposure ◽  
Well Being ◽  
Research Field ◽  
Decision Makers ◽  
Spectral Simulation ◽  
Design Decisions ◽  
Computational Tools ◽  
Recent Developments ◽  
The Impact

Abstract Recent developments in the lighting research field have demonstrated the importance of a proper exposure to light to mediate several of our behavioral and physiological responses. However, we spend nowadays around 90% of our time indoors with an often quite limited access to bright daylight. To be able to anticipate how much the built environment actually influences our light exposure, and how much it may ultimately impact our health, well-being, and productivity, new computational tools are needed. In this paper, we present a first attempt at a simulation workflow that integrates a spectral simulation tool with a light-driven prediction model of alertness. The goal is to optimize the effects of light on building occupants, by informing the decision makers about the impact of different design choices. The workflow is applied to a case study to provide an example of what learnings can be expected from it.

The Effect of Light on Sleep and Sleep-Related Physiological Factors Among Patients in Healthcare Facilities: A Systematic Review

2019 ◽  
Vol 12 (4) ◽  
pp. 116-141
Author(s):  
Khatereh Hadi ◽  
Jennifer R. Du Bose ◽  
Young-Seon Choi
Keyword(s):  
Light Exposure ◽  
Bright Light ◽  
Light Sources ◽  
Related Factors ◽  
Healthcare Facilities ◽  
New Findings ◽  
Healthcare Environments ◽  
The Impact ◽  
Improve Patient ◽  
Bright Light Exposure

Objectives: Lighting is one of the environmental factors which can improve patient sleep in healthcare environments. Due to the high degree of variation in study designs and results on this topic, the implications have been difficult to interpret. This review consolidates studies on the impact of bright light exposure on sleep to identify lighting conditions that can be applied and researched in future healthcare environments. Methods: We searched for peer-reviewed articles on the impact of light on sleep or sleep-related outcomes in healthcare settings. We provided detailed analysis of the direct links between light and sleep, and a more cursory analysis of links between light and sleep-related factors, from 34 articles which met our inclusion criteria. Results: The current state of the literature includes evidence on how various durations and intensities of morning, midday, and evening bright light exposure, as well as whole-day light exposure interventions can improve specific aspects of sleep. Lighting interventions differed in all attributes (illuminance levels, exposure time, exposure duration, and spectral qualities) but showed promising results in improving patients’ sleep. Conclusions: Short-term bright light exposure in the morning, up to 2 hr of moderate (3,000–10,000 lux) morning exposures, up to 4 hr of moderate evening exposure, and whole-day exposures to lower illuminance levels (<3,000 lux) can improve patient sleep outcomes. Based on new findings on the mechanism through which light impacts sleep, future studies should be more specific about the spectral qualities of light sources.

Surface Colour Matching under Conditions of Multiple Illuminants

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 190-190 ◽  
Author(s):  
H Irtel
Keyword(s):  
Light Source ◽  
Green Light ◽  
Light Sources ◽  
Local Contrast ◽  
Colour Constancy ◽  
Lighting Condition ◽  
3 Dimensional ◽  
Special Cases ◽  
Type Pattern ◽  
Light And Shadow

Most theories of colour constancy assume a flat coloured surface and a single homogenous light source. Natural situations, however, are 3-dimensional (3-D), are hardly ever restricted to a single light source, and object illumination is never homogenous. Here, two special cases of secondary light sources with sharp boundaries were simulated on a computer screen: a house-like 3-D object with colour patches in sunlight and shadow, and a Mondrian-type pattern with a coloured transparency covering some of the colour patches. Subjects made ‘paper’-matches between colour patches in light and shadow and between patches under the transparency and without the transparency. Matching did not depend on whether the simulated lighting condition was natural (yellow light, blue shadow) or artificial (green light, magenta shadow). Patches under a coloured transparency produced lightness constancy but subjects could not discount chromaticity shifts induced by the transparency. The number of context patches (2 vs 6) made no difference, and it made no difference whether the transparency covered the Mondrian completely or only partially. These results indicate that subjects were not able to use local contrast cues at sharp illumination boundaries to discount for the illuminant.

scholarly journals Blue light attracts nocturnally migrating birds

The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
Xuebing Zhao ◽  
Min Zhang ◽  
Xianli Che ◽  
Fasheng Zou
Keyword(s):  
Blue Light ◽  
Field Experiments ◽  
Red Light ◽  
Light Pollution ◽  
Artificial Light ◽  
Light Sources ◽  
Rapid Urbanization ◽  
Phototactic Response ◽  
Migrating Birds ◽  
The Impact

Abstract Light pollution is increasing and artificial light sources have great impacts on animals. For migrating birds, collisions caused by artificial light pollution are a significant source of mortality. Laboratory studies have demonstrated that birds have different visual sensitivities to different colors of light, but few field experiments have compared birds’ responses to light of different wavelengths. We used 3 monochromatic lights (red, green, and blue) and polychromatic yellow light to study the impact of wavelength on phototaxis at 2 gathering sites of nocturnally migrating birds in Southwest China. For both sites, short-wavelength blue light caused the strongest phototactic response. In contrast, birds were rarely attracted to long-wavelength red light. The attractive effect of blue light was greatest during nights with fog and headwinds. As rapid urbanization and industrialization cause an increase in artificial light, we suggest that switching to longer wavelength lights is a convenient and economically effective way to reduce bird collisions.

scholarly journals Light Exposure during Days with Night, Outdoor, and Indoor Work

2019 ◽  
Vol 63 (6) ◽  
pp. 651-665 ◽  
Author(s):  
Stine Daugaard ◽  
Jakob Markvart ◽  
Jens Peter Bonde ◽  
Jens Christoffersen ◽  
Anne Helene Garde ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Exposure ◽  
Spectral Composition ◽  
Working Hours ◽  
Well Being ◽  
Outdoor Workers ◽  
Light Levels ◽  
Light Intensities ◽  
Treatment Of Depression ◽  
Night Shifts

Abstract Objective To assess light exposure during days with indoor, outdoor, and night work and days off work. Methods Light intensity was continuously recorded for 7 days across the year among indoor (n = 170), outdoor (n = 151), and night workers (n = 188) in Denmark (55–56°N) equipped with a personal light recorder. White light intensity, duration above 80, 1000, and 2500 lux, and proportion of red, green, and blue light was depicted by time of the day and season for work days and days off work. Results Indoor workers’ average light exposure only intermittently exceeded 1000 lux during daytime working hours in summer and never in winter. During daytime working hours, most outdoor workers exceeded 2500 lux in summer and 1000 lux in winter. Night workers spent on average 10–50 min &gt;80 lux when working night shifts. During days off work, indoor and night workers were exposed to higher light intensities than during work days and few differences were seen between indoor, outdoor, and night workers. The spectral composition of light was similar for indoor, outdoor, and night workers during days at and off work. Conclusion The night workers of this study were during night hours on average exposed for a limited time to light intensities expected to suppress melatonin. The indoor workers were exposed to light levels during daylight hours that may reduce general well-being and mood, especially in winter. Outdoor workers were during summer daylight hours exposed to light levels comparable to those used for the treatment of depression.

scholarly journals Long-Term Comparison of Attraction of Flying Insects to Streetlights after the Transition from Traditional Light Sources to Light-Emitting Diodes in Urban and Peri-Urban Settings

2019 ◽  
Vol 11 (22) ◽  
pp. 6198 ◽  
Author(s):  
Roy H. A. van Grunsven ◽  
Julia Becker ◽  
Stephanie Peter ◽  
Stefan Heller ◽  
Franz Hölker
Keyword(s):  
Light Emitting Diodes ◽  
Spectral Composition ◽  
Mercury Vapor ◽  
World Market ◽  
Relative Difference ◽  
Urban Setting ◽  
Light Sources ◽  
Urban Settings ◽  
Light Emitting ◽  
The Impact

Among the different light sources used for street lighting, light-emitting diodes (LEDs) are likely to dominate the world market in the coming years. At the same time, the spectral composition of nocturnal illumination is changing. Europe and many other areas worldwide have implemented bans on energy-inefficient lamps, such as the still very common mercury vapor lamps. However, the impact of artificial light on insects is mostly tested with light-traps or flight-intercept traps that are used for short periods only. By comparing the numbers of insects attracted by street lamps before and after replacing mercury vapor light sources (MV) with light emitting diodes, we assessed the impact in more typical (urban and peri-urban) settings over several years. We found that LED attracted approximately half of the number of insects compared to MV lights. Furthermore, most insect groups are less drawn by LED than by MV, while Hymenoptera are less attracted by MV than by LED. Thus, the composition of the attracted communities differed between the light sources, which may impact ecosystem processes and functions. In green peri-urban settings more insects are attracted than in an urban setting, but the relative difference between the light sources is the same.

The Luminescence Properties of BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ Phosphors

2010 ◽  
Vol 663-665 ◽  
pp. 137-140 ◽  
Author(s):  
Jia Yue Sun ◽  
Wei Hang Zhang ◽  
Yu Jing Lan ◽  
Hai Yan Du
Keyword(s):  
Red Light ◽  
Green Light ◽  
Green Emission ◽  
Infrared Light ◽  
Solid State Method ◽  
Light Excitation ◽  
Bright Green ◽  
State Method ◽  
Uv Excitation ◽  
Color Emission

Two-color emission phosphors BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ have been synthesized by the high temperature solid-state method. The as-prepared BaGd2(MoO4)4: Eu3+, Er3+, Yb3+ phosphors can emit intense red light under 395 nm UV excitation, while it will show bright green light upon 980 nm infrared light excitation. It is found that the red emission peaks at 595 and 614 nm should be attributed to 5D0-7F1 and 5D0-7F2 transitions of Eu3+, respectively. The green emission peaks centered at 532 and 553 nm under 980 nm excitation, are attributed to Er3+ transitions from 4H11/2 -4I15/2 and 4S3/2-4I15/2, respectively.

Sign in / Sign up

Export Citation Format

Share Document