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Emission spectra of different light sources: (a) incandescent tungsten light bulb; (b) fluorescent white light bulb; (c) energy efficient light bulb; (d) white LED light bulb; (e) blue LED light bulb; (f) black LED light bulb; (g) morning sunlight; (h) midday sunlight; (i) sunlight at sunset; and (j) comparison of sunlight at midday (red), morning (yellow) and at sunset (green).
Source publication
This study aimed to investigate the biological impact of exposure on domestic light emitting diodes (LED) lighting using the free-living nematode Caenorhabditis elegans as a model. Nematodes were separately exposed to white LED light covering the range of 380-750 nm, blue light at 450 nm and black light at 380-420 nm for one life cycle (egg to adul...
Contexts in source publication
Context 1
... spectra of incandescent tungsten bulb, fluorescent white bulb, energy efficient light bulb, white LED light bulb, blue LED light bulb, black LED light bulb and sunlight (morning, midday and sunset) are shown in Figure 1. Incandescent tung- sten light was mostly free of blue light, fluorescent white light and energy efficient light bulbs showed 2 blue bands at 400 nm and 435 nm, white LED light showed high proportion of the blue light at 450 nm, blue LED light showed only one band at 455 nm and black LED light showed three blue bands at 385/ 410/435 nm. ...
Context 2
... tung- sten light was mostly free of blue light, fluorescent white light and energy efficient light bulbs showed 2 blue bands at 400 nm and 435 nm, white LED light showed high proportion of the blue light at 450 nm, blue LED light showed only one band at 455 nm and black LED light showed three blue bands at 385/ 410/435 nm. Sunlight showed a continuous spectrum from 375 to 750 nm; however, the intensity of the blue light was highest at midday and lowest at sunset as shown in Figure 1. Effect of LED light exposure on hatching, development and population increase of C. elegans ...
Citations
... To ensure that these images offer identifiable areas, they should capture light emitted by both a fluorescent and an incandescent lamp. These types of lamps are chosen due to their distinctive characteristics: fluorescent lamps provide five recognizable wavelength peaks within the desired range of 400-1052 nm, while incandescent lamps emit a continuous spectrum [36]. Consequently, the calibration process necessitates spectral images acquired from a 6500 K fluorescent lamp and either a 3000 K incandescent lamp or a 3000 K fluorescent lamp. ...
Hyperspectral imaging has revolutionized various scientific fields by enabling a detailed analysis of objects and materials based on their spectral signatures. However, the high cost and complexity of commercial hyperspectral camera systems limit their accessibility to researchers and professionals. In this paper, a do-it-yourself (DIY) hyperspectral camera device that offers a cost-effective and user-friendly alternative to hyperspectral imaging is presented. The proposed device leverages off-the-shelf components, commercially available hardware parts, open-source software, and novel calibration techniques to capture and process hyperspectral imaging data. The design considerations, hardware components, and construction process are discussed, providing a comprehensive guide for building the device. Furthermore, the performance of the DIY hyperspectral camera is investigated through experimental evaluations with a multi-color 3D-printed box in order to validate its sensitivities to red, green, blue, orange and white colors.
... Many existing applications often achieve the chromaticity of these lights through a mixture of RGB broadband lights (comprising a wavelength range of 400-700 nm); thus, recovering narrowband responses is an ill-posed problem. However, many of the existing studies directly use such composed lights for downstream applications [35,[44][45][46], and in some works, researchers use learning-based methods (convolutional neural networks (CNNs)) [47,48] or Bayesian regularization methods [49] to recover the narrowband spectrums. Moreover, many of these existing works use commercial off-theshelf RGB cameras [50] as the detector, which is suboptimal, since the RGB filters essentially limit the incoming light and its resulting bands within the visible range. ...
Hyperspectral imaging is capable of capturing information beyond conventional RGB cameras; therefore, several applications of this have been found, such as material identification and spectral analysis. However, similar to many camera systems, most of the existing hyperspectral cameras are still passive imaging systems. Such systems require an external light source to illuminate the objects, to capture the spectral intensity. As a result, the collected images highly depend on the environment lighting and the imaging system cannot function in a dark or low-light environment. This work develops a prototype system for active hyperspectral imaging, which actively emits diverse single-wavelength light rays at a specific frequency when imaging. This concept has several advantages: first, using the controlled lighting, the magnitude of the individual bands is more standardized to extract reflectance information; second, the system is capable of focusing on the desired spectral range by adjusting the number and type of LEDs; third, an active system could be mechanically easier to manufacture, since it does not require complex band filters as used in passive systems. Three lab experiments show that such a design is feasible and could yield informative hyperspectral images in low light or dark environments: (1) spectral analysis: this system’s hyperspectral images improve food ripening and stone type discernibility over RGB images; (2) interpretability: this system’s hyperspectral images improve machine learning accuracy. Therefore, it can potentially benefit the academic and industry segments, such as geochemistry, earth science, subsurface energy, and mining.
... We consistently refer to shelf-stable derivatives, while in situ generated compounds have been excluded from the present survey. We collected only transformations that took place by using a light source emitting exclusively in the visible range [36] to avoid a UV contribution to the outcome of the reaction. The following examples have been classed according to the type of bond broken. ...
The use of visible light to promote synthetic processes has been emerging rapidly in recent years. In the frame of eco-sustainable strategies involving the generation of reactive intermediates (especially radicals), the search for compounds able to directly undergo the photocleavage of a labile X–Y bond by using visible photons appears an intriguing alternative to the use of a colored photocatalyst. This review focuses on the recent efforts to design compounds having such X–Y moieties to be used in radical chemistry under photocatalyst-free conditions.
... Mitochondria provide much of the energy for cell function in the form of ATP. They have optical characteristics and absorb short wavelength light that is regarded as harmful and is associated with reduced function [1][2][3][4][5]. ATP production requires integrity of the mitochondrial inner membrane, which is where respiratory complexes are located. ...
Increased blue light exposure has become a matter of concern as it has a range of detrimental effects, but the mechanisms remain unclear. Mitochondria absorb short wavelength light but have a specific absorbance at 420nm at the lower end of the human visual range. This 420nm absorption is probably due to the presence of porphyrin. We examine the impact of 420nm exposure on drosophila melanogaster mitochondria and its impact on fly mobility. Daily 15 mins exposures for a week significantly reduced mitochondrial complex activities and increased mitochondrial inner membrane permeability, which is a key metric of mitochondrial health. Adenosine triphosphate (ATP) levels were not significantly reduced and mobility was unchanged. There are multiple options for energy/time exposure combinations, but we then applied single 420nm exposure of 3h to increase the probability of an effect on ATP and mobility, and both were significantly reduced. ATP and mitochondrial membrane permeability recovered and over corrected at 72h post exposure. However, despite this, normal mobility did not return. Hence, the effect of short wavelengths on mitochondrial function is to reduce complex activity and increasing membrane permeability, but light exposure to reduce ATP and to translate into reduced mobility needs to be sustained.
... Early sources of human-made light, such as liquid fuel lamps, emit a significant amount of energy greater than 700 nm, much of which is in the infrared range outside the spectral sensitivities of most visual and non-visual receptors (Elvidge et al. 2010). The oldest forms of electric lights (incandescent, 1879) also emit disproportionally longer wavelengths (600-700 nm), resulting in light that, at dim levels, is visually similar to the naturally occurring skyglow produced by the stars and moon which peaks at around 560 nm (Schubert and Kim 2005;Veilleux and Cummings 2012;Kohyama et al. 2014;Archer 2015;Abdel-Rahman et al. 2017). Alternative technologies such as fluorescent, metal halide, high pressure sodium, and low pressure sodium lights were developed in the late 1900s in efforts to improve the efficiency and visual quality of night light, and these have reduced infrared Light pollution and photosensitivity 3 radiance with strong peaks around 500-600 nm (Kok and Hengstberger 1974;Tibbits et al. 1983;Knight and Mitchell 1988;Islam et al. 2012;Abdel-Rahman et al. 2017;Longcore et al. 2018). ...
... The oldest forms of electric lights (incandescent, 1879) also emit disproportionally longer wavelengths (600-700 nm), resulting in light that, at dim levels, is visually similar to the naturally occurring skyglow produced by the stars and moon which peaks at around 560 nm (Schubert and Kim 2005;Veilleux and Cummings 2012;Kohyama et al. 2014;Archer 2015;Abdel-Rahman et al. 2017). Alternative technologies such as fluorescent, metal halide, high pressure sodium, and low pressure sodium lights were developed in the late 1900s in efforts to improve the efficiency and visual quality of night light, and these have reduced infrared Light pollution and photosensitivity 3 radiance with strong peaks around 500-600 nm (Kok and Hengstberger 1974;Tibbits et al. 1983;Knight and Mitchell 1988;Islam et al. 2012;Abdel-Rahman et al. 2017;Longcore et al. 2018). ...
... LEDs are also unique in that they are commercially available in a wide range of color temperatures (Box 1) that vary in spectral composition. Cool white LEDs, designed to mimic daylight, emit a broad spectrum (380-700 nm) with strong irradiance peaks at around 450 nm (Migaud et al. 2007;Abdel-Rahman et al. 2017;Alaasam et al. 2018;Longcore et al. 2018;Kim et al. 2019). As mentioned previously, 450 nm light is particularly stimulatory for human photoreceptors that suppress melatonin, and so there is a market for cool white LEDs that increase attention, alertness, and productivity in humans (Schubert and Kim 2005;Mills et al. 2007;Viola et al. 2008;Hertog et al. 2015). ...
Synopsis
Artificial light at night (ALAN) is a pervasive anthropogenic pollutant, emanating from urban and suburban developments and reaching nearly all ecosystems from dense forests to coastlines. One proposed strategy for attenuating the consequences of ALAN is to modify its spectral composition to forms that are less disruptive for photosensory systems. However, ALAN is a complicated pollutant to manage due to the extensive variation in photosensory mechanisms and the diverse ways these mechanisms manifest in biological and ecological contexts. Here, we highlight the diversity in photosensitivity across taxa and the implications of this diversity in predicting biological responses to different forms of night lighting. We curated this paper to be broadly accessible and inform current decisions about the spectrum of electric lights used outdoors. We advocate that efforts to mitigate light pollution should consider the unique ways species perceive ALAN, as well as how diverse responses to ALAN scale up to produce diverse ecological outcomes.
... LCUs that use LEDs now dominate the market. The emission spectrum from LED lights is different and narrower than that from QTH units, [23][24][25] and most contemporary LED curing lights deliver at least 2 to 3 times the irradiance of QTH units. Manufacturers of some LED units now claim 26 their products deliver as much as 5,000 mW/cm 2 of irradiance, and most of this light is emitted in the blue wavelength region from 430 through 480 nm. ...
... [22][23][24]35 Although blue light is present all around us and helps regulate our circadian rhythms, 8 light can damage the light-sensing cells (photoreceptors) in the retina. 25,[39][40][41][42][43][44][45] It is also known that the juvenile lens absorbs less blue light than the adult lens and that their retinas are more susceptible to the effects of blue light. 33,46,47 Based on numerous animal studies of acute exposure to blue light, daily exposure limits to protect the eyes of all workers have been set by many organizations, such as the International Commission on Non-Ionizing Radiation Protection, 30 the European Parliament, 31 and the American Conference of Governmental Industrial Hygienists. ...
... 32 As the use of electronic devices such as flat-screen televisions, computers, smartphones, tablets, and fluorescent and white light LED operatory lights has become more prevalent, 47,48 health-related concerns have arisen that all humans, not just dentists, are being exposed to excessive amounts of blue light. 25,38,49 A significant adverse association between touchscreen use and nighttime sleep, and sleep onset has already been reported. 8,36,41,50 A 2016 report from the American Medical Association 38 expressed concerns that the blue light from the LEDs in streetlamps might suppress melatonin production, disrupt the circadian rhythm, cause discomfort glare, and have detrimental environmental effects. ...
Background:
Dental light-curing units (LCUs) are powerful sources of blue light that can cause soft-tissue burns and ocular damage. Although most ophthalmic research on the hazards of blue light pertains to low levels from personal electronic devices, computer monitors, and light-emitting diode light sources, the amount of blue light emitted from dental LCUs is much greater and may pose a "blue light hazard."
Methods:
The authors explain the potential risks of using dental LCUs, identify the agencies that provide guidelines designed to protect all workers from excessive exposure to blue light, discuss the selection of appropriate eye protection, and provide clinical tips to ensure eye safety when using LCUs.
Results:
While current literature and regulatory standards regarding the safety of blue light is primarily based on animal studies, sufficient evidence exists to suggest that appropriate precautions should be taken when using dental curing lights. The authors found it difficult to find on the U.S. Food and Drug Administration database which curing lights had been cleared for use in the United States or Europe and could find no database that listed which brands of eyewear designed to protect against the blue light has been cleared for use. The authors conclude that more research is needed on the cumulative exposure to blue light in humans. Manufacturers of curing lights, government and regulatory agencies, employers, and dental personnel should collaborate to determine ocular risks from blue light exist in the dental setting, and recommend appropriate eye protection. Guidance on selection and proper use of eye protection should be readily accessible.
Conclusions and practical implications:
The Centers for Disease Control and Prevention Guidelines for Infection Control in the Dental Health-Care Setting-2003 and the Occupational Safety and Health Administration Bloodborne Pathogen Standard do not include safety recommendations or regulations that are directly related to blue light exposure. However, there are additional Occupational Safety and Health Administration regulations that require employers to protect their employees from potentially injurious light radiation. Unfortunately, it is not readily evident that these regulations apply to the excessive exposure to blue light. Consequently employers and dental personnel may be unaware that these Occupational Safety and Health Administration regulations exist.
... The melt-quenching method and the physical appearance of the prepared glass samples under sunlight (a) and fluorescent light (b). The emission spectra of both light sources were obtained from Ref.[45]. ...
Customisation of the lasing characteristics of rare-earth ions activating various materials for practical applications requires fundamental knowledge of the structure and dielectric correlation. Based on these factors, a new series of glass ceramics of composition (40-x)P2O5 –30B2O3 –30ZnSO4 –xHo2O3 (x = 0.0, 0.4, 0.5, and 0.6 mol%) were prepared using the melt-quenching method. As-prepared samples were characterised using various techniques to determine the effect of holmium ion (Ho³⁺) doping on their structure and dielectric traits. XRD patterns of as-quenched samples confirmed their glass-ceramic characteristics. Holmium ion concentration-dependent Raman and FTIR analyses revealed the structural enhancement in the glass ceramics. The presence of Zn, S, B, P, O, and Ho in the glass ceramics was disclosed by the XPS spectra, and the ratio of the bridging to non-bridging oxygen atoms was evaluated by analysing the O1s peaks. The recorded room temperature complex impedance spectra of the samples in the range of 103–105 Hz were influenced by the predominant glassy and dormant crystalline structures. The UV–Vis–NIR data (in the range of 206–310 nm) and the impedance spectra (3×1012–3×1014 nm) were analysed to evaluate the dielectric features of the samples. The considerable increase in the frequency-dependent AC conductivity and its slight reduction with Ho³⁺ incorporation was ascribed to the dopant ion-induced formation of quasi-molecular complexes (such as bridging oxygen and ligands) in the host network. A correlation between the structure and dielectric attributes of the titled glass ceramics was established. In short, the Ho³⁺-incorporated customised structures and dielectric properties of the newly proposed glass-ceramic composition were affirmed to be prospective for sundry applications.
... The onychophoran Euperipatoides rowelli was not attracted by light but instead significantly avoided illumination with wave lengths ranging from UV to green light (Beckmann et al., 2015). It has been further reported that sensitivity to blue light is wide spread among invertebrates with monochromatic vision which has been attributed to the maximum distribution of energy of solar radiation at 480 nm (Menzel, 1979;Bowmaker and Hunt, 1999;Wang et al., 2003;Kelber and Roth, 2006).The nematode Caenorhabtidis elegans when exposed to high energy blue light indicated stress with a spurt in the production of Reactive Oxygen Species (ROS) (Abdel-Rahman et al., 2017). Among the invertebrates, ___________________________________________________________________________ behavioural and physiological responses of annelids to light intensity and colours have not been adequately investigated. ...
... Also the present study indicated a depleted protein level in earthworms exposed to lights relative to dark. Abdel-Rahman et al. (2017) conducted an experiment on the nematode C. elegans to study the impact of exposure to light emitting diode (LED) domestic lighting and found that high-energy blue light (blue and black emitting lights) induces stress in the animal, affecting egg hatching, development, population, progeny, locomotion and survival. The stress response was also associated with the production of reactive oxygen species (ROS). ...
The biological activities of invertebrates are influenced by environmental factors. Surface feeding soil animals such as epigeic earthworms are likely to be influenced by the type and intensity of light unlike deep dwelling species which live in dark. This study reports the effects of low intensity light exposures on the survivability, biomass, vermicomposting efficiency, tissue protein, lipid peroxidation and activities of three stress enzymes, acetylcholinesterase, lactate dehydrogenase and catalase of the vermicomposting earthworm, Eudrilus eugeniae. Consistent exposure of the animal to low intensity white, blue, green and red LED lights for 42 days in semi-decomposed organic substrate indicated decreased protein level, increased lipid peroxidation and enzyme activities in the animal with respect to those kept in dark. The study further indicated that darkness favours survivability, biomass gain and vermicomposting efficiency in this earthworm.
... When a laser microbeam is fired on a specimen, it is thought that the extreme heat and pressure generated denature proteins and DNA 27 . Similarly, prolonged LED exposure has also been shown to cause harmful effects on C. elegans and to cause retinal damage in rats [28][29][30] . It has also been reported that C. elegans possess LITE-1 photoreceptors which are sensitive to laser and UV light stimuli which are responsible for inducing negative photo-tactic responses 31 . ...
Nematode bioassays are extensively conducted worldwide, either for screening anthelmintic drugs or for assessing the toxicity of drug candidates. Recently, the US Environmental Protection Agency mandated the use of invertebrate models including nematodes especially Caenorhabditis elegans, for toxicity testing as an alternative to rodent models. The significance of nematode bioassays in the biological sciences is escalating, but no standardized protocol is available to assess nematode mortality in a liquid medium. Manual counting under white light is the only approach currently practiced, which exhibit large variabilities and false positive results. Here, we describe an innovative counting strategy that employs light-emitting diode (LED) technology. We found that the nematodes stopped moving under white light (360-760 nm) when administered with sub-lethal dosage (LC50) of a toxic drug, whereas they responded rapidly to blue (450-490 nm) and ultraviolet (UV) (100-400 nm) LED lights. Furthermore, paralyzed nematodes responded in less than 5 seconds to a LED pulse. The response to the LED stimulus was distinctively noted in C. elegans dauers, which squirmed away from illuminated sites within seconds. LED produced an incoherent beam, and uniformly distributed light across the sampling area. In conclusion, this method is more accurate than the conventional counting techniques, and enables us to differentiate paralyzed and dead nematodes virtually in real-time. Furthermore, this technique would appear to be suitable for incorporating a motion-sensor based automated system.
... According to studies by Abdel-Rahman et al., the exposure for 72 hours blue light can cause oxidative stress in C. elegans, producing negative effects on its locomotion, survival, oviposition, besides reducing the number of eggs or delaying its maturation. 19 Thus, it is possible that the effect of the blue light (450 nm), in addition to the reduction of motility, also influenced to a smaller amount of worms for PS curcumin, demetoxicurcumin and the curcuminoid mixture of PDI group compared to its referent PS group, but not statistically confirmed. However, it is desirable that the nematicidal effect is caused by the association between the photosensitizer and light, producing a more controlled effect on only one localized target capable of retaining the PS. ...
