Broad-spectrum Light Research Articles

Infrared response in photocatalytic polymeric carbon nitride for water splitting via an upconversion mechanism

Broad-spectrum light activation in photocatalytic materials is considered vital for effective solar-to-hydrogen energy conversion. Here, we propose an upconversion process in oxygen-doped polymeric carbon nitride (C3N4) nanosheets, resulting in high photocatalytic activity for hydrogen generation from water splitting under infrared light irradiation. Due to the upconversion, the photoexcited electrons are transferred to the conduction band, and a σ* carbon-oxygen orbital localized on the triazine matrix ring resulting from oxygen doping extends the lifetime of photogenerated electrons, which increases the photocatalytic activity under both infrared and visible light. Our material exhibits high apparent quantum efficiency of 0.014% and 23% at 850 nm and 420 nm, respectively. Under infrared light (λ ≥ 800 nm, 24 mW cm−2), the hydrogen production rate of our material is 22.84 μmol h−1 g−1, which can reach a yield similar to that of pristine C3N4 under visible light.

Unraveling the Roles of Hot Electrons and Cocatalyst toward Broad Spectrum Photocatalytic H2 Generation of g‐C3N4 Nanotube

Exploiting active photocatalysts with broad spectrum light response is a priority target in the field of photocatalysis. Herein, integrating Au and CoO nanoparticles with g‐C3N4 hollow nanotubes, a promising ternary photocatalyst with wide‐light spectrum response (420–650 nm) is designed, in which Au nanoparticles play the dual role of plasmonic electron donor and reduction cocatalyst, while CoO nanoparticles act as oxidation cocatalyst. The optimum H2 evolution rates of the ternary hybrid reach 238.7 and 4.9 μmol under the irradiation of visible light and monochromic light of 650 nm, respectively. Localized surface plasmon resonance (LSPR) can promote charge‐carrier generation in the g‐C3N4, and the appropriate band alignment between the Au and g‐C3N4 is favorable for hot electron transfer from Au to g‐C3N4, which makes this ternary hybrid possess extra hot electrons for water reduction reaction under a wider solar spectrum. Furthermore, Au as a reduction cocatalyst and CoO as an oxidation cocatalyst can effectively impel the charge separation and restrain charge recombination, which is also responsible for the enhanced photocatalytic activity. This work affords a credible strategy for the rational construction of plasmon‐assisted photocatalysts for the wider‐spectrum appliance of solar energy.

Single pixel hyperspectral Cherenkov-excited fluorescence imaging with LINAC X-ray sheet scanning and spectral unmixing.

Cherenkov light induced from megavolt (MV) X-rays during external beam radiotherapy serves as an internal light source to excite phosphors or fluorophores within biological tissues for molecular imaging. The broad spectrum of Cherenkov light leads to significant spectral overlap with any luminescence emission and, to overcome this problem, a single pixel hyperspectral imaging methodology was demonstrated here by coupling the detection with light sheet scanning and filtered back projection reconstruction of hyperspectral images. Thin scanned sheets of MV X-rays produce Cherenkov light to illuminate the planes deep within the tissue-simulating media. A fluorescence probe was excited by Cherenkov light, and a complete hyperspectral sinogram of the data was obtained through translation and rotation of the beam. Hyperspectral 2D images finally were reconstructed. Through this approach of spectral unmixing, it was possible to resolve hyperspectral images of both the Cherenkov and resulting fluorescence intensity from molecular sensors.

P.765 The role of N-acetyl-D-glucosamine kinase in protecting proteinopathies

This study evaluates the potential of continuous wave Ultraviolet C light (UV-C) and broad-spectrum intense pulsed light (in this study referred to as High Intensity Light Pulses, HILP) for the inactivation of pathogens of public concern in powdered infant formula (PIF) producers. To achieve this goal a sequential set of experiments were performed, firstly in clear liquid media, secondly on the surface of spherical beads under agitation and, finally in PIF. L. innocua was the most sensitive microorganism to both technologies under all conditions studied with reductions exceeding 4 log10 cycles in PIF. In the clear liquid medium, the maximum tolerance to light was observed for C. sakazakii against UV-C light and for B. subtilis spores against HILP, with a fluence of approximately 17 mJ/cm2 required for a 1 log10 cycle inactivation (D value) of each species. In PIF it was possible to inactivate >99% of the vegetative cell populations by HILP with a fluence of 199 mJ/cm2 and of B. subtilis spores by doubling the fluence. By contrast, for UV-C treatments a fluence of 2853 mJ/cm2 was needed for 99.9% reduction of C. sakazakii, which was the most light-resistant microorganism to UV-C. Results here obtained clearly show the potential for light-based interventions to improve PIF microbiological safety.

A novel transillumination meibography device for in vivo imaging of mouse meibomian glands

PurposeWhile mouse models of dry eye disease (DED) have been developed, studies evaluating the role of the meibomian glands limited by the inability to temporally document changes. In this report we describe the development of a novel mouse transillumination meibography device and assess the ability of this device to detect age-related changes in the meibomian glands of young and old mice. MethodsThe mouse meibography device was comprised of a 3 mm wide right angle prism attached to broad spectrum light source by an optical fiber. Eyelids were then pulled over the prism using double tooth forceps and imaged using a stereomicroscope and low light level camera. Meibomian glands from four young and four old male, BALB/c mice were then imaged and analyzed using ImageJ. ResultsIn young mice, meibography documented the presence of 7–8 meibomian glands appearing as black and distinct eyelid structures with the length shorter in the lower eyelid compared to the upper eyelids. Eyelids of old mice showed apparent dropout of meibomian glands along with smaller and more irregularly shaped acini. The mean acini area of one meibomian gland was 0.088 ± 0.025 mm2 in young mice and 0.080 ± 0.020 mm2 in old mice (p = 0.564), but the Meibomian gland density was significantly lower in older mice (41.7 ± 6.4%, 27.3 ± 4.2%) (p = 0.021). ConclusionWe have developed an in vivo meibography device that may prove useful in sequentially documenting changes during development of meibomian gland dysfunction and following treatment.

Responses and preferences of salmon louse (Lepeophtheirus salmonis Krøyer 1836) copepodids to underwater artificial light sources

The ectoparasitic salmon louse (Lepeophtheirus salmonis, Krøyer 1836) remains a major disease problem and cost driver in commercial Atlantic salmon (Salmo salar L) farming and is also implicated in the decline of wild salmon stocks. The parasite feeds on mucus and blood causing skin damage on its host (i.e. leads to reduced welfare and disease resistance). Underwater lights (UL) are being used regularly in open-cage salmon aquaculture to delay maturation and increase feeding rates during the dark season. The aim of this study has therefore been to supply basic experimental data on the responses of the infectious copepodid stage of L. salmonis to discrete underwater light sources with different light qualities and intensities. The collective movement of a copepodid population in response to light sources was tested in a laboratory-based machine vision system using automated image processing. Copepodids always moved towards the light source even at low light intensities (1.5 × 10−3 μmol m−2 s−1) within a broad spectrum of visible light as well as near-UV. It is therefore plausible that subsea light sources frequently used in salmon farming under certain conditions can attract salmon lice copepodids and increase infection pressure. Moreover, the findings of our study support that light traps may be used to catch planktonic salmon lice. The actual effect of underwater light sources on the local distribution of salmon lice should be tested by controlled plankton sampling or monitoring in the vicinity of light sources compared to the surrounding water.

Clade-specific variation in susceptibility of Candida auris to broad-spectrum ultraviolet C light (UV-C).

Candida auris is an emerging and often multidrug-resistant fungal pathogen with an exceptional ability to persist on hospital surfaces. These surfaces can act as a potential source of transmission. Therefore, effective disinfection strategies are urgently needed. We investigated the efficacy of ultraviolet C light (UV-C) disinfection for C. auris isolates belonging to 4 different clades. In vitro testing of C. auris isolates was conducted using 106 colony-forming units (CFU) spread on 20-mm diameter steel carriers and exposed to a broad-spectrum UV-C light source for 10, 20, and 30 minutes at a 1.5 m (5 feet) distance. Post-UV survivors on the coupons were subsequently plated. Colony counts and log reductions were recorded, calculated, and compared to untreated control carriers. Identification of all isolates were confirmed by MALDI-TOF and morphology was visualized by microscopy. We observed an increased susceptibility of C. auris to UV-C in 8 isolates belonging to clades I, II and IV with increasing UV exposure time. The range of log kill (0.8-1.19) was highest for these isolates at 30 minutes. But relatively no change in log kill (0.04-0.35) with increasing time in isolates belonging to clade III were noted. Interestingly, C. auris isolates susceptible to UV-C were mostly nonaggregating, but the isolates that were more resistant to UV exposure formed aggregates. Our study suggests variability in susceptibility to UV-C of C. auris isolates belonging to different clades. More studies are needed to assess whether a cumulative impact of prolonged UV-C exposure provides additional benefit.

Multiplexed endoscopic imaging of Barrett’s neoplasia using targeted fluorescent heptapeptides in a phase 1 proof-of-concept study

Improved methods for early cancer detection arising from Barrett’s oesophagus (BE) are still needed. Imaging molecular expression patterns in BE patients can target neoplasia. We demonstrate a multiplexed fluorescence imaging...

Efecto del estrés salino sobre la morfología y fitoquímica de orégano mexicano (Lippia graveolens Kunth) cultivado in vitro

Las plantas, al ser organismos sésiles sufren diferentes tipos de estreses bióticos y abióticos. En este trabajo se cultivaron in vitro plantas de orégano, bajo condiciones de estrés salino (NaCl 25 mM), en diferentes fuentes de luz: blanca (CTL), ultravioleta tipo C (UV-C) y de amplio espectro (AE). Se evaluaron cambios morfológicos en las plantas tratadas, así como parámetros fitoquímicos (fenoles y flavonoides totales y la capacidad antioxidante). Los tratamientos NaCl/CTL y AE mostraron el mayor número de yemas activadas. La luz UV-C mostró la menor cantidad de yemas y de altura de planta, sin embargo, no se observó efecto de la salinidad. La luz UV-C causó el menor número de hojas, así como raíces adventicias. No parece haber injerencia de la condición salinidad en estos resultados. La condición que provocó el mayor contenido de fenoles fue la luz UV-C y la que provocó el mayor contenido de flavonoides fue la combinación NaCl/UV-C. La combinación NaCl/AE causó la mayor capacidad antioxidante con el método DPPH y ABTS. No se observó una correlación entre el contenido de fenoles y la capacidad antioxidante.

Phototactic Behavior of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is a well-known aphid predator in its native Asian habitat. Currently, H. axyridis are predominantly released for aphid control in China; however, light traps and colored sticky cards also were widely used to control aphid pests, which results in population reduction of H. axyridis. This study used 15 monochromatic and whole-spectrum lights to investigate whether H. axyridis has a particular light intensity and spectral preference. Positive phototaxis was found in both H. axyridis adults and larvae to a broad specturm of light. The phototactic responses of adult H. axyridis showed significant similarity to that of larvae. Female H. axyridis had four sensitivity maxima at 414, 492, 504, and 568 nm, male H. axyridis had four maxima of sensitivity at 380, 492, 504, and 549 nm, and H. axyridis larvae also had four maxima of sensitivity at 414, 504, 549, and 568 nm. The phototactic responses of H. axyridis to various monochromatic lights did not significantly differ between sexes. The larval response to a broad spectrum of light was significantly less than that of adults. Furthermore, H. axyridis adults of both sexes showed an increased phototactic response at low intensities and a decreased response at high intensities for both blue light and green light. Moreover, the phototactic response of both female and male H. axyridis was strongest at 10 lux. The males of H. axyridis are more sensitive to light intensity than females; however, the H. axyridis light intensity experiments between sexes showed no significant differences. These behavioral differences could be exploited for the development of selected colored light traps used for insect pest management.

Fabrication and Characterization of Seawater Temperature Sensor with Self-Calibration Based on Optical Microfiber Coupler Interferometer

In this paper, a novel high-sensitivity temperature sensor with two sensing regions based on optical microfiber coupler interferometer (OMCI) for ocean application is proposed. The OMCI sensor is constructed by connecting Faraday mirrors to the two ports of the microfiber coupler respectively. Its sensing characteristics analysis and experimental test are conducted. Using a broad-spectrum light source as input light, temperature sensor demodulation can be implemented by tracking the drift of the characteristic wavelength (dip wavelength or peak wavelength) of the reflection spectrum. Experimental results show that the temperature sensitivity of the OMCI sensor can reach 1007.4 pm/°C and the detection dynamic range up to 17.6 °C. Besides, due to the two sensing regions in OMCI, self-calibration of seawater temperature sensing and optimization of multi-parameter cross-sensitive demodulation are performed by affecting the non-equal-arm interferometer through a specific package design of the external environment. The sensor has the advantages of high sensitivity, large dynamic range, small size, easy to manufacture, which will play an important role in the practical application of marine environment monitoring.

Comparison of Violet, Red, and Green Light on Early-Stage Common Bean (Phaseolus vulgaris L.) Development

The energy efficiency of light-emitting diodes (LEDs) makes them attractive for indoor plant lighting. LEDs, however, do not produce broad-spectrum light efficiently. The effects of LED lighting on common bean (Phaseolus vulgaris L.) growth are not well known. This study sought to find the colors of light that most effectively grow common bean plants under indoor conditions. The hypothesis was that red light would promote early common bean growth better, both qualitatively and quantitatively, than violet or green light. After planting the seeds in soil, 20 common bean plants were each grown under red, or green, or violet LED lights (PHILIPS®) (8 watt), or natural sunlight, for 16 days: a total of 80 plants. Bonferroni adjusted t-tests showed that the plants under the violet light grew significantly taller than the plants under red or green light with p-values 0.000 respectively; the plants under red or green light had significantly larger leaves than those under the violet light with p-values 0.000. Qualitative observations (based upon visual inspections of leaf health, maturity, and root development) revealed the plants under red light were the healthiest, most mature, and exhibited the most developed roots—followed by those under green light. The findings of this study suggested early common bean growth performed better under red light than under violet or green light.

Melanin and Melanin-Like Hybrid Materials in Regenerative Medicine.

Melanins are a group of dark insoluble pigments found widespread in nature. In mammals, the brown-black eumelanins and the reddish-yellow pheomelanins are the main determinants of skin, hair, and eye pigmentation and play a significant role in photoprotection as well as in many biological functions ensuring homeostasis. Due to their broad-spectrum light absorption, radical scavenging, electric conductivity, and paramagnetic behavior, eumelanins are widely studied in the biomedical field. The continuing advancements in the development of biomimetic design strategies offer novel opportunities toward specifically engineered multifunctional biomaterials for regenerative medicine. Melanin and melanin-like coatings have been shown to increase cell attachment and proliferation on different substrates and to promote and ameliorate skin, bone, and nerve defect healing in several in vivo models. Herein, the state of the art and future perspectives of melanins as promising bioinspired platforms for natural regeneration processes are highlighted and discussed.

Rational regulation on charge spatial separation and directional migration in the yolk-shell structural SiO2/Ni2P/rGO/Cd0.5Zn0.5S nanoreactor for efficient photocatalytic H2 evolution

High-efficiency light utilization and prolonged lifetime of photo-induced charge carriers is a key step towards superior photocatalytic H2 evolution. Herein, the design of a novel spatially separated Ni2P co-catalyst decorated SiO2/rGO/Cd0.5Zn0.5S yolk-shell structural photocatalytic nanoreactor is reported. In this system, the advantages of ultrathin mesoporous shell and yolk-shell structure not only facilitate the mass diffusion with short length, but also allow broad-spectrum light absorption and increase the density of catalytic active sites. Importantly, the photo-generated electrons can be directionally injected from the outermost Cd0.5Zn0.5S shell to the spatially separated Ni2P co-catalyst. The dynamic behaviors of photo-induced charge carriers can be rationally regulated by the suitable energy level alignment and the built-in electric fields derived from both sides of embedded rGO interlayer. The synergistic effects of the excellent light-harvesting ability, more exposed active sites and improved charge separation efficiency significantly boosted the photocatalytic performances of hydrogen evolution. As a result, the optimal SiO2/Ni2P/rGO/Cd0.5Zn0.5S composite exhibited the highest hydrogen generation of 11.65 mmoL‧g−1‧h−1, even after five cycles. This work proposes new insights into the design of the efficient hollow sphere structural heterojunctions for photocatalytic water splitting applications.

On Demand Light-Degradable Polymers Based on 9,10-Dialkoxyanthracenes.

Light induced degradation of polymers has drawn increasing interest due to the need for externally controllable modulation of materials properties. However, the portfolio of polymers, that undergo precisely controllable degradation, is limited and typically requires UV light. A novel class of backbone-degradable polymers that undergo aerobic degradation in the presence of visible light, yet remain stable against broad-spectrum light under anaerobic conditions is reported. In this design, the polymer backbone is comprised of 9,10-dialkoxyanthracene units that are selectively cleaved by singlet oxygen in the presence of green light as confirmed by NMR and UV/vis spectroscopy. The resulting polymers have been processed by electrohydrodynamic (EHD) co-jetting into bicompartmental microfibers, where one hemisphere is selectively degraded on demand.

Co, Ni-based nanoparticles supported on graphitic carbon nitride nanosheets as catalysts for hydrogen generation from the hydrolysis of ammonia borane under broad-spectrum light irradiation

From the viewpoint of tailoring the atomic and nanoscale structures of semiconductors to enhance the solar-to-hydrogen energy conversion, we employed an in-situ gas template-assisted co-polymerization route, where melamine and 2,4,6-triaminopyrimidine were co-monomers and NH4Cl was the in-situ gas template, to synthesize porous broad-spectrum light-responsive carbon nitride nanosheet (termed as CNN) species with increased π-electron availability. Then we developed CNN-supported Co and Ni nanoparticles (NPs) for catalytic hydrogen generation from aqueous ammonia borane (NH3BH3) under light irradiation (λ ≥ 420 nm) at room temperature. Though all the Co-based catalysts had the similar activities with total turnover frequency (TOF) values of 37.5–44.1 min−1 in the dark, they exhibited significantly different and enhanced photocatalytic activities. Remarkably, the optimized catalyst had a total TOF value of 123.2 min−1, exceeding the values of reported non-noble metal catalysts. Moreover, the porous CNN species possessed the C-substitution for N, tunable narrow bandgaps of 0.71–2.34 eV and efficient separation of photogenerated charge carriers. This resulted in the enriched electron density of metal NPs and the apparent quantum yield of 66.9% at 420 nm.

Enhanced full solar spectrum photocatalysis by nitrogen-doped graphene quantum dots decorated BiO2-x nanosheets: Ultrafast charge transfer and molecular oxygen activation

It is still challenging to produce superoxide and hydroxyl radicals through activating molecular oxygen under broad-spectrum light in environmental photocatalysis. In this work, nitrogen-doped graphene quantum dots (N-GQDs) modified BiO2-x nanosheets were successfully fabricated and exhibited superior performance in light-harvesting, electron-hole pair separation, and full-spectrum driven molecular oxygen activation. The hybridized photocatalyst with a N-GQDs weight ratio of 0.4wt% (GBO-0.4) exhibited an excellent photocatalytic activity toward tetracycline degradation with a 4.0-fold, 2.9-fold and 5.5-fold higher reaction rate under full-spectrum, visible and near-infrared light irradiations than that of pure BiO2-x, respectively. The enhanced photocatalytic performance was ascribed to the electron collection effect and up-conversion photoluminescence properties of the N-GQDs as well as the synergistic effects of the developed nanojunction. Efficient molecular oxygen activation was achieved via the construction of a bulk-to-surface channel between BiO2-x and N-GQDs. DFT calculations were also used to explore the geometric and electronic structure variations of BiO2-x after the introduction of N-GQDs. The high photostability and mineralization ability toward tetracycline degradation confirm the promising application prospects of the N-GQDs/BiO2-x photocatalyst. This work provides a rational strategy for designing 0D/2D nanoscale heterostructure photocatalysts with improved full-spectrum photoactivity for environmental applications.

Lignin as a UV Light Blocker-A Review.

Lignin is the by-product of pulp and paper industries and bio-refining operations. It is available as the leading natural phenolic biopolymer in the market. It has chromophore functional groups and can absorb a broad spectrum of UV light in range of 250–400 nm. Using lignin as a natural ingredient in sunscreen cream, transparent film, paints, varnishes and microorganism protection has been actively investigated. Both in non-modified and modified forms, lignin provides enhancing UV protection of commercial products with less than a 10% blend with other material. In mixtures with other synthetic UV blockers, lignin indicated synergic effects and increased final UV blocking potential in compare with using only synthetic UV blocker or lignin. However, using lignin as a UV blocker is also challenging due to its complex structure, polydispersity in molecular weight, brownish color and some impurities that require more research in order to make it an ideal bio-based UV blocker.

Investigating the in-Situ Doping Effect of Niobium Pentoxide Nanostructures on Their Electronic Surface Properties

The release of large quantities of effluents to the environment as wastewater affects the quality of drinking water and it is a serious concern for the environment and for the public health. Often wastewater contains substances that are toxic, carcinogenic and resistant to biodegradation [1]. Thereby, the stringent regulations imposed by environmental and governmental agencies to improve the quality of water, require more efficient wastewater treatment techniques. Advanced oxidative processes (AOPs) consist of non-selective and efficient oxidative degradation of organic pollutants using chemical species with high oxidative power such as hydroxyl radicals [1]. In one of the AOP methods, light interacts with semiconductors generating excitons by the transfer of electrons from the valence band to the conduction one. The excitons react with oxygen and water forming hydroxyl radicals, which degrade organic molecules. Actually, photodegradation is an effective-cost method to treat industrial effluents [1]. However, this technology suffers from some challenges such as insufficient utilization of visible-light. Therefore, advances in photodegradation processes require the development of new semiconductors, the evaluation of their electronic and surface properties, to enhance the efficiency of hydroxyl radicals’ generation in presence of UV light and broad spectrum light source. [2][3]. Different metal oxides, were exploited for such a purpose like TiO2, SnO2, ZnO2, Fe3O2, Al2O3, showing different performances in terms of degradation rates [1]. Niobium pentoxide has been investigated for different applications such as humidity, gas and chemical sensing, electrochromic devices and catalysis due to its thermodynamic stability, high corrosion resistance, biocompatibility and Bronsted acidic properties [2]. At the same time, is one of the least studied metal oxides, which makes it attractive for fundamental studies. Nb2O5 is a wide band-gap semiconductor, with a band gap of 3.4 - 4 eV depending on its morphological features, meaning that it can be used as a photocatalyst only when activated with ultraviolet irradiation [4][5][6]. In this work, we investigate the impact of the nature and content of the doping element on the electronic surface properties of Nb2O5 nanostructures aiming at widen its photon absorption in the electromagnetic spectrum.The Nb2O5 nanoparticles were synthesized by hydrothermal synthesis at 150°C, for 2h, by mixing ammonium niobium oxalate with the different percentages of dopant precursors: N, Cu, and Ta. The structural and morphological characterization of the samples was carried out by X-ray diffraction (XRD) and Scanning electronic microscopy (SEM). The optical properties were investigated by UV-Visible-NIR diffuse-reflectance spectroscopy (DRS) to define the effective optical band gap, Ultraviolet photoelectron spectroscopy (UPS) to calculate the work function of the materials and by X-ray photoelectron spectroscopy (XPS) to determine the valence band edge, leading to the complete construction of the energy diagram of the different synthesized nanoparticles. The successful doping of Nb2O5 nanostructures with 1 wt% of Ta, Cu or N lead to a narrowing of the optical band gap as illustrated in Figure 1. The reduction of the optical band gap of Nb2O5 is at least of 0.5 EV through the doping with tantalum but around 1 eV with nitrogen. The correlation between the electronic surface properties and the structure of the materials will be discussed.AcknowledgementsThe authors would like to thank the funding from NSERC (Strategic partnership program, Canada) and FAPESP (BEPE 2018/17279-1, Brazil).

Broad-spectrum light pollution suppresses melatonin and increases West Nile virus–induced mortality in House Sparrows (Passer domesticus)

Abstract Artificial light at night (ALAN) has become a pervasive anthropogenic stressor for both humans and wildlife. Although many negative impacts of ALAN on human health have been identified, the consequences for infectious disease dynamics are largely unexplored. With the increase in popularity of energy efficient light-emitting diodes (LEDs), the effects of spectral composition of ALAN have also come into question. Previous studies showed that exposure to low levels of incandescent ALAN extended the infectious period of House Sparrows (Passer domesticus) infected with West Nile virus (WNV) without affecting mortality rates, thus increasing the pathogen initial reproductive rate (R0) by ~41%. Here, we asked whether exposure to broad-spectrum (3000 K [Kelvin; unit of color temperature]) ALAN suppressed melatonin, a hormone implicated in ALAN-induced physiological consequences, in House Sparrows. We then asked whether amber-hue bulbs (1800 K) could ameliorate the effects of WNV on individual sparrows, and whether broad-spectrum or blue-rich bulbs (3000 K and 5000 K, respectively) could exacerbate them. We found that exposure to low intensity (~5 lux) broad-spectrum (3000 K) ALAN significantly suppressed melatonin levels throughout the night. Second, we found that exposure to broad-spectrum and blue-rich (3000 + 5000 K) lights did not affect WNV viremia but did increase WNV-induced mortality. Conversely, birds exposed to amber-hue (1800 K) ALAN had lower viremia and mortality rates similar to controls (i.e. natural light conditions). This study demonstrates that ALAN affects melatonin regulation in birds, but this effect, as well as ALAN influences on infectious disease responses, can be ameliorated by particular lighting technologies.