Artificial Light Exposure Research Articles

Protective Effect of the Aqueous Extract of Deschampsia antarctica (EDAFENCE®) on Skin Cells against Blue Light Emitted from Digital Devices

Skin is being increasingly exposed to artificial blue light due to the extensive use of electronic devices. This, together with recent observations reporting that blue light—also known as high-energy visible light—can exert cytotoxic effects associated with oxidative stress and promote hyperpigmentation, has sparked interest in blue light and its potential harmful effects on skin. The photoprotective properties of new extracts of different botanicals with antioxidant activity are therefore being studied. Deschampsia antarctica (Edafence®, EDA), a natural aqueous extract, has shown keratinocyte and fibroblast cell protection effects against ultraviolet radiation and dioxin toxicity. In this regard, we studied the protective capacity of EDA against the deleterious effects of artificial blue light irradiation in human dermal fibroblasts (HDF) and melanocytes. We analyzed the impact of EDA on viability, cell morphology, oxidative stress, melanogenic signaling pathway activation and hyperpigmentation in HDF and melanocytes subjected to artificial blue light irradiation. Our results show that EDA protects against cell damage caused by artificial blue light, decreasing oxidative stress, melanogenic signaling pathway activation and hyperpigmentation caused by blue light irradiation. All these findings suggest that EDA might help prevent skin damage produced by artificial blue light exposure from screen of electronic devices.

Assessing coastal artificial light and potential exposure of wildlife at a national scale: the case of marine turtles in Brazil

Coastal areas provide critical nesting habitat for marine turtles. Understanding how artificial light might impact populations is key to guide management strategies. Here we assess the extent to which nesting populations of four marine turtle species—leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), hawksbill (Eretmochelys imbricata) and two subpopulations of loggerhead (Caretta caretta) turtles—are exposed to light pollution across 604 km of the Brazilian coast. We used yearly night-time satellite images from two 5-year periods (1992–1996 and 2008–2012) from the US Air Force Defense Meteorological Satellite Programme (DMSP) to determine the proportion of nesting areas that are exposed to detectable levels of artificial light and identify how this has changed over time. Over the monitored time-frame, 63.7% of the nesting beaches experienced an increase in night light levels. Based on nest densities, we identified 54 reproductive hotspots: 62.9% were located in areas potentially exposed to light pollution. Light levels appeared to have a significant effect on nest densities of hawksbills and the northern loggerhead turtle stock, however high nest densities were also seen in lit areas. The status of all species/subpopulations has improved across the time period despite increased light levels. These findings suggest that (1) nest site selection is likely primarily determined by variables other than light and (2) conservation strategies in Brazil appear to have been successful in contributing to reducing impacts on nesting beaches. There is, however, the possibility that light also affects hatchlings in coastal waters, and impacts on population recruitment may take longer to fully manifest in nesting numbers. Recommendations are made to further this work to provide deeper insights into the impacts of anthropogenic light on marine turtles.

A Note on the Surface Deterioration of Scrimber Composites Exposed to Artificial Ageing

The effect of ultraviolet radiation on the surface deterioration of scrimber composites with different densities and levels of resin content was investigated for this paper. The surface color, gloss, roughness, and wettability of the samples were investigated to determine the extent of surface changes due to accelerated ageing. The results indicated that all scrimber composites exhibited variation in the color of their surfaces during artificial xenon light exposure. After artificial accelerated ageing, the surface contact angle and roughness were found to increase, whereas the surface gloss and surface free energy decreased. Furthermore, it was observed that the density and resin content of the scrimber composites contributed to reductions in their color variation, wettability, and roughness during weathering, which suggested that the density and resin content played important roles in determining their surface photodegradation properties. Artificial ageing resulted in the degradation of lignin and hemicellulose, thus causing severe surface characteristics.

Utilization of Cladophora glomerata for Organic Substance Removal in Laundry Wastewater with Artificial Light Exposure

Macroalgae is an alternative technology for reduce organic content in wastewater. This study develop the performance of Cladophora glomerata species as a Macroalgae to remove laundry wastewater pollutants with artificial light. Light exposure conducted in 12 hours and 24 hours exposure to the algal reactor with nutrient variance concentration. The results of this study showed that macroalgae succeeded in reducing organic matter as COD to ±25.81% and BOD to ±54% within in 5 days. Performance of algae to decrease organic substance determine the effect algal-bacteria symbiosis which prevail in the reactor. Furthermore, nutrient content could affect the algal ability to remove the organic substance

Ecological light pollution affects anuran calling season, daily calling period, and sensitivity to light in natural Brazilian wetlands.

Ecological light pollution alters an environment's light cycle, potentially affecting photoperiod-controlled behavior. Anurans, for example, generally breed nocturnally, and the influence of light pollution on their natural history may therefore be especially strong. In this study, we tested this hypothesis by measuring male calling behavior of anuran communities in natural wetlands in southern Brazil exposed or not exposed to street lights. We recorded seasonal and diel calling activity and calling response to a light pulse. The peak calling season differed between continuously lit and unlit locations with most species in illuminated wetlands shortening their calling season and calling earlier in the year. In unlit breeding sites, Boana pulchella, Pseudis minuta, and Pseudopaludicola falcipes confined their calling activity to well-defined hours of the night, but in continuously lit areas, these species called more continuously through the night. A 2-minute light pulse inhibited calling, but only in unlit wetlands. After a light pulse, frogs quickly resumed calling-suggesting acclimatization to brief artificial light exposure. Our field experiment presents a convincing example of ecological light pollution showing that artificial light alters the seasonal and diel calling time of some South American wetland anurans. It also documents their acclimatization to brief lighting when being continuously exposed to light.

Comparison on the Aging of Woods Exposed to Natural Sunlight and Artificial Xenon Light.

To investigate the relationship between sunlight and artificial light sources on the weathering of wood, three woods, namely, Tectona grandis L.F. (teak), Stereospermum colais (mabberley), and Dicorynia guianensis (basralocus), were tested under natural sunlight for 733 days and artificial xenon light for 180 h, respectively. A comparison between sunlight and artificial xenon light was made based on surface color changes at various intervals. The results showed that the woods suffered from more severe aging in the artificial xenon light exposure than that in the natural sunlight exposure. At the early stage of exposure, very good relationships were found between 70 days under natural sunlight weathering and 60 h under artificial xenon light weathering. Compared with natural sunlight, about a 30 times faster aging process was identified in the artificial xenon light. However, the linear relationship vanished at the later aging stage. It was found that the color change fluctuated in natural sunlight, while it increased steadily in artificial xenon light. The wood species affected the aging of woods. In natural sunlight exposure, the color change decreased in the order of mabberley > teak > basralocus, while in artificial xenon light exposure, color change decreased in the order of mabberley > basralocus > teak due to the easier volatilization of extractives in artificial xenon light than in natural sunlight.

Does bottle color protect red wine from photo‐oxidation?

Even if bottled red wines have an extended shelf life, they undergo several chemical changes, and producers are well aware of the importance of the packaging. However, there is a lack of research into the effect of light on their composition. Therefore, the storage conditions of a Sangiovese wines with respect to artificial light exposure (present/absent) and bottle color (transparent, brown, and green) were investigated. Thirty‐five chemical characteristics (physicochemical, UV‐VIS indexes, and volatile compounds) were recorded after 6 months of storage. Light exposure caused significant differences in total SO2 and a shift from red to yellow/orange color. For wines kept in transparent bottles, total red pigments, total phenol index, monomeric anthocyanins, copigmentation, chemical age, and some volatile compounds showed significant differences, depending on whether it was exposed to light or not. On the contrary, light exposure was found not significant for the wine stored in green and brown bottles, Finally, an overall increase in variability was found for light‐exposed wine in transparent bottles which could be considered, in itself, a measure of lack of quality.

Telling the Time with a Broken Clock: Quantifying Circadian Disruption in Animal Models.

Circadian rhythms are approximately 24 h cycles in physiology and behaviour that enable organisms to anticipate predictable rhythmic changes in their environment. These rhythms are a hallmark of normal healthy physiology, and disruption of circadian rhythms has implications for cognitive, metabolic, cardiovascular and immune function. Circadian disruption is of increasing concern, and may occur as a result of the pressures of our modern 24/7 society—including artificial light exposure, shift-work and jet-lag. In addition, circadian disruption is a common comorbidity in many different conditions, ranging from aging to neurological disorders. A key feature of circadian disruption is the breakdown of robust, reproducible rhythms with increasing fragmentation between activity and rest. Circadian researchers have developed a range of methods for estimating the period of time series, typically based upon periodogram analysis. However, the methods used to quantify circadian disruption across the literature are not consistent. Here we describe a range of different measures that have been used to measure circadian disruption, with a particular focus on laboratory rodent data. These methods include periodogram power, variability in activity onset, light phase activity, activity bouts, interdaily stability, intradaily variability and relative amplitude. The strengths and limitations of these methods are described, as well as their normal ranges and interrelationships. Whilst there is an increasing appreciation of circadian disruption as both a risk to health and a potential therapeutic target, greater consistency in the quantification of disrupted rhythms is needed.

Nest height is affected by lamppost lighting proximity in addition to nestbox size in urban great tits

Both natural and artificial light have proximate influences on many aspects of avian biology, physiology and behaviour. To date artificial light at night is mostly considered as being a nuisance disrupting for instance sleep and reproduction of diurnal species. Here, we investigate if lamppost night lighting affects cavity‐nesting bird species inside their breeding cavity. Nest height in secondary cavity‐nesting species is the result of trade‐offs between several selective forces. Predation is the prevailing force leading birds to build thin nests to increase the distance towards the entrance hole. A thin nest may also limit artificial light exposure at night. Yet, a minimum level of daylight inside nesting cavities is necessary for adequate visual communication and/or offspring development. Against this background, we hypothesised that avian nest‐building behaviour varies in response to a change in night lighting. We monitored nest height of urban great tits Parus major during six years and found that it varied with artificial light proximity. The birds built thinner nests inside nestboxes of various sizes in response to increasing lamppost night light availability at the nest. In large nestboxes, the nests were also thinner when a lamppost was present in the territory. Whether this relationship between artificial night lighting and nest height reflects a positive or negative effect of urbanisation is discussed in the light of recent experimental studies conducted in rural populations by other research groups.

Outdoor Artificial Nighttime Light and Use of Hypnotic Medications in Older Adults: A Population-Based Cohort Study.

Outdoor artificial nighttime light is increasingly recognized as a form of environmental pollution. Excessive nighttime light exposure, whether from indoor or outdoor sources, has been associated with a number of deleterious effects on human health. We performed a population-based cohort study in South Korea to assess the possible association between outdoor nocturnal lighting and insomnia in older adults, as measured by prescriptions for hypnotic drugs. This study used data from the 2002-2013 National Health Insurance Service-National Sample Cohort (NHIS-NSC), and a total of 52,027 adults who were age 60 years or older were included in the study. Light data were based on satellite mapping of artificial light. The usage data of two hypnotic drugs, zolpidem (N05CF02) and triazolam (N05CD05), were extracted from the NHIS-NSC records. Of the 52,027 patients in this cohort, 11,738 (22%) had prescriptions for hypnotic drugs. Increasing outdoor artificial nighttime light exposure (stratified by quartile) was associated with an increased prevalence of hypnotic prescriptions and daily dose intake. Compared with individuals in the lowest quartile 1, the regression coefficients for prescription days and daily defined doses of all hypnotic drugs and certain hypotonic drugs were significantly higher among those living in areas with higher outdoor artificial nighttime light (quartiles 2 through 4). Outdoor artificial nighttime light exposure was significantly associated with prescription of hypnotic drugs in older adults. These findings are consistent with the hypothesis that outdoor artificial nighttime light may cause sleep disturbances.

Circadian Health and Light: A Report on the National Heart, Lung, and Blood Institute's Workshop.

Despite the omnipresence of artificial and natural light exposure, there exists little guidance in the United States and elsewhere on light exposure in terms of timing, intensity, spectrum, and other light characteristics known to affect human health, performance, and well-being; in parallel, there is little information regarding the quantity and characteristics of light exposure that people receive. To address this, the National Center on Sleep Disorders Research, in the Division of Lung Diseases, National Heart, Lung, and Blood Institute, held a workshop in August 2016 on circadian health and light. Workshop participants discussed scientific research advances on the effects of light on human physiology, identified remaining knowledge gaps in these research areas, and articulated opportunities to use appropriate lighting to protect and improve circadian-dependent health. Based on this workshop, participants put forth the following strategic intent, objectives, and strategies to guide discovery, measurement, education, and implementation of the appropriate use of light to achieve, promote, and maintain circadian health in modern society.

The Effect of Light Exposure at Night (LAN) on Carcinogenesis via Decreased Nocturnal Melatonin Synthesis.

In mammals, a master clock is located within the suprachiasmatic nucleus (SCN) of the hypothalamus, a region that receives input from the retina that is transmitted by the retinohypothalamic tract. The SCN controls the nocturnal synthesis of melatonin by the pineal gland that can influence the activity of the clock’s genes and be involved in the inhibition of cancer development. On the other hand, in the literature, some papers highlight that artificial light exposure at night (LAN)-induced circadian disruptions promote cancer. In the present review, we summarize the potential mechanisms by which LAN-evoked disruption of the nocturnal increase in melatonin synthesis counteracts its preventive action on human cancer development and progression. In detail, we discuss: (i) the Warburg effect related to tumor metabolism modification; (ii) genomic instability associated with L1 activity; and (iii) regulation of immunity, including regulatory T cell (Treg) regulation and activity. A better understanding of these processes could significantly contribute to new treatment and prevention strategies against hormone-related cancer types.

Design of Monitoring System for Measuring the Impact of Light Intensity of Artificial Lights on Human Circadian Cycles in Web-Based Inpatient Rooms

Light is a source of energy that is needed in human life. In hospitals, artificial lighting is very necessary, especially in operating rooms that are impermeable to natural light and must be sterile from room bacteria. Artificial light exposure that does not meet the SNI standard for room lighting causes various problems. Therefore, in this study, a tool to control the intensity of artificial light according to the SNI standard in hospitals was designed. This research uses measurement, calculation and comparison methods. The first measurement is to measure the value of the light intensity of the lamp, then measure the temperature value in the room, the last one is to sterilize the room bacteria. From these measurements, values ??are obtained to be compared in reaching conclusions. From this research, it can be concluded that the monitoring system with the LDR light sensor can read the value of the light intensity properly according to the digital lux meter in the morning at 400 lux, 200 lux in the daytime, and 120 lux at night. Then the DHT-11 sensor can read the temperature value in the room according to the HTC comparison with the morning temperature is 25 degrees, daytime 29 degrees, afternoon 27 days, and night is 24 degrees. To help kill room bacteria, a Utraviolet lamp is used with a light for 2 hours in the morning.

0117 Impact of Light Exposure during Sleep on Cardiometabolic Function

Artificial light exposure is increasingly widespread, particularly at night. Light exposure at night is known to impact circadian rhythms such as melatonin and sleep, and disturbances in these rhythms have been shown to affect cardiometabolic function. As such, the aim of this study was to test the hypothesis that light exposure at night during sleep negatively impacts cardiometabolic outcomes, possibly via disruptions to sleep architecture and melatonin profiles. Twenty healthy adults 18–40 years of age were randomized into Dark-Dark (DD) or Dark-Light (DL) groups and run in parallel for a three day and two night stay. Participants had 8 hours of sleep opportunity each night starting at habitual bedtime determined from one week of actigraphy with sleep diary. The DL group (n=10, 2 males, ages 26.61 ± 4.64 years, BMI 23.25 ± 3.94 kg/m^2) slept in the dark < 3 lux on Night 1 and slept in overhead room light of 100 lux on Night 2, while the DD group (n=10, 4 males, ages 26.78 ± 5.15 years, BMI 24.25 ± 3.71 kg/m^2) slept in the dark <3 lux on both Nights 1 and 2. Overnight polysomnography and hourly blood sampling for melatonin were collected on both nights. Oral glucose tolerance tests were performed on both mornings following sleep in the dark or 100 lux of light. Repeated measures ANOVA were performed between groups (DL vs. DD) with Day (Day 1 vs Day 2) and Time of Day as within-subject factors. Homeostatic model assessment of insulin resistance values were significantly higher (p<0.05) in the morning following sleep in the light (DL group) compared to sleep in the dark (DD group). This effect was primarily due to increased insulin levels for DL compared to DD group, for which there was a trend for group by day effect (p<0.09). A single night of light exposure during sleep acutely impacts insulin resistance, and chronic overnight exposure may have long-term effects on metabolic function. This research was supported National Institutes of Health grants 5T32HL7909, P01AG11412, and 8UL1TR000150-05.

Fluorescent light exposure incites acute and prolonged immune responses in zebrafish (Danio rerio) skin

Artificial light produces an emission spectrum that is considerably different than the solar spectrum. Artificial light has been shown to affect various behavior and physiological processes in vertebrates. However, there exists a paucity of data regarding the molecular genetic effects of artificial light exposure. Previous studies showed that one of the commonly used fluorescent light source (FL; 4100K or “cool white”) can affect signaling pathways related to maintenance of circadian rhythm, cell cycle progression, chromosome segregation, and DNA repair/recombination in the skin of male Xiphophorus maculatus. These observations raise questions concerning the kinetics of the FL induced gene expression response, and which biological functions become modulated at various times after light exposure. To address these questions, we exposed zebrafish to 4100K FL and utilized RNA-Seq to assess gene expression changes in skin at various times (1 to 12h) after FL exposure. We found 4100K FL incites a robust early (1−2h) transcriptional response, followed by a more protracted late response (i.e., 4–12h). The early transcriptional response involves genes associated with cell migration/infiltration and cell proliferation as part of an overall increase in immune function and inflammation. The protracted late transcriptional response occurs within gene sets predicted to maintain and perpetuate the inflammatory response, as well as suppression of lipid, xenobiotic, and melatonin metabolism.

Effect of light exposure during sleep on the curricular and extracurricular activities of medical students

Introduction: Many researches have demonstrated the effect of artificial light exposure during sleep on the circadian rhythm that controls the sleep-wake cycle. Lighting during sleep suppresses the melatonin that is responsible for the sleep-wake cycle. Consequently, this affects student’s academic performance and their involvement in curricular and extracurricular activities.Aims: We conducted a study to find the effects of the exposure of light during sleep on student’s sleep quality, level of concentration in class, academic performances and involvement in extracurricular activities.Material and methods: A cross sectional study was performed by distributing a questionnaire to 238 second year medical undergraduate students.Results: We found that 84% of the respondents usually slept with light off. Students sleeping with light on reported having a lower quality of sleep and also reported having more difficulty concentrating in class. As compared to students with lights off during sleep, those who reported sleeping with the light on also reported scoring lower marks and less extracurricular activity,Conclusion: Sleeping with lights on during sleep appears to be related to poor sleep quality, lowered level of concentration in class, lower student’s academic performances and less involvement in extracurricular activities.Bangladesh Journal of Medical Science Vol.16(4) 2017 p.541-544

Fluorescent light induces neurodegeneration in the rodent nigrostriatal system but near infrared LED light does not

We investigated the effects of continuous artificial light exposure on the mouse substantia nigra (SN). A three month exposure of C57Bl/6J mice to white fluorescent light induced a 30% reduction in dopamine (DA) neurons in SN compared to controls, accompanied by a decrease of DA and its metabolites in the striatum. After six months of exposure, neurodegeneration progressed slightly, but the level of DA returned to the basal level, while the metabolites increased with respect to the control. Three month exposure to near infrared LED light (∼710nm) did not alter DA neurons in SN, nor did it decrease DA and its metabolites in the striatum. Furthermore mesencephalic cell viability, as tested by [3H]DA uptake, did not change. Finally, we observed that 710nm LED light, locally conveyed in the rat SN, could modulate the firing activity of extracellular-recorded DA neurons. These data suggest that light can be detrimental or beneficial to DA neurons in SN, depending on the source and wavelength.

Effects of pH, Electrolyte, Humic Acid, and Light Exposure on the Long-Term Fate of Silver Nanoparticles.

We investigated the evolution in silver nanoparticle (AgNP) properties during a series of 10-50 day experiments on suspensions with different pH (5-9), electrolyte type (NaNO3 and NaCl) and concentration (2 and 6 mM), Suwannee River humic acid (SRHA) concentration (0-13.2 mg C/L), and light exposure (artificial sun light exposure for 8 h per day or dark). Of these factors, pH most influenced the AgNPs' properties as it modifies surface charge as well as AgNP dissolution and oxidation and Ag+ reduction reactions. As a result, particle behavior differed in basic and acidic conditions. Trends with pH varied, however, based on the electrolyte and SRHA concentration. In the presence of chloride which forms AgCl(s), for example, we observed the particle size decreased with increasing pH. The opposite was observed in identical systems in NaNO3. This behavior was modified by SRHA, with increasing SRHA reducing dissolution and enhancing stability. Light exposure enhanced processes resulting in AgNP dissolution, resulting in higher dissolved Ag concentrations than under similar conditions in the dark. Overall, our results highlight how AgNP properties evolve over time and provide insight needed to confidently extend model system behavior to predict the environmental fate of AgNPs.

Nutrition in the spotlight: metabolic effects of environmental light.

Use of artificial light resulted in relative independence from the natural light-dark (LD) cycle, allowing human subjects to shift the timing of food intake and work to convenient times. However, the increase in artificial light exposure parallels the increase in obesity prevalence. Light is the dominant Zeitgeber for the central circadian clock, which resides within the hypothalamic suprachiasmatic nucleus, and coordinates daily rhythm in feeding behaviour and metabolism. Eating during inappropriate light conditions may result in metabolic disease via changes in the biological clock. In this review, we describe the physiological role of light in the circadian timing system and explore the interaction between the circadian timing system and metabolism. Furthermore, we discuss the acute and chronic effects of artificial light exposure on food intake and energy metabolism in animals and human subjects. We propose that living in synchrony with the natural daily LD cycle promotes metabolic health and increased exposure to artificial light at inappropriate times of day has adverse effects on metabolism, feeding behaviour and body weight regulation. Reducing the negative side effects of the extensive use of artificial light in human subjects might be useful in the prevention of metabolic disease.

Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure.

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53J/cm(2) raised the vitamin D2 content to significantly (P<0.001) higher levels of 67.1±9.9μg/g dry weight (DW) than sun exposure (3.9±0.8μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2)=0.96, P<0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.