Red Illumination Research Articles

Highly sensitive MoS2 photodetector on polarized thin-film lithium niobate with extremely low dark current

To obtain high performance optoelectronic devices, ferroelectric materials have received a lot of attention due to the various emerging effects on channel materials induced by the ferroelectric polarization. In this work, a special photodetector with the channel material of a triple-layer MoS2 on a polarized LiNbO3 substrate was fabricated. The device has a high responsivity of 113.1[Formula: see text]A/W and a high specific detectivity of up to [Formula: see text] Jones under red illumination, while maintaining the rise and fall time of 32 and 22[Formula: see text]ms, respectively. Meanwhile, the dark current of this device can be as low as [Formula: see text][Formula: see text]A with a bias of 5.0[Formula: see text]V because the channel material MoS2 is almost depleted under the internal electrical field induced by the polarized LiNbO3. This work promises a feasible way for the future development of integrated high-sensitivity photodetectors.

Direct air capture using halophilic Cyanobacterium aponinum PCC10605 under illumination of light-emitting diodes in marine environment

Excessive carbon dioxide (CO2) emissions have become a disaster, calling for an effective way to reduce atmospheric CO2 content. Cyanobacteria, also known as blue-green algae, are potent natural carbon sinks with efficient photosynthesis and produce valuable compounds. Herein, we demonstrated the excellent properties of Cyanobacterium aponinum PCC10605 (Capo) in maintaining growth and protein accumulation under salt stress and red light-emitting diodes (LEDs) illumination at 660 nm under direct air capture (DAC) condition. Multi-factor optimization from response surface methodology revealed the best condition of 25 °C, 70 μE light intensity, 17 g/L salt, 16 to 8 h for light to dark period, and 6 mM nitrogen to yield the highest combination of 1.49 g/L biomass and 19.1 % C-phycocyanin (C-PC) content. Capo also thrived in 50 % seawater from Penghu, Taiwan where its DAC capacity was confirmed using an elemental analyzer, showing that 48.2 % carbon content was equivalent to specific capture ratio of 1.75 g-CO2/g-DCW and volumetric efficiency of 2.62 g-CO2/L, respectively. Finally, scaling up cultivation in 2-liter photobioreactor was successfully carried out under red LED illumination. The potential of Capo in reducing atmospheric CO2 level represents an advancement in sustainable biotechnology for climate change mitigation.

Effectiveness of light-emitting diodes for arsenic and mercury accumulation by Ceratophyllum demersum L.: An innovative advancement in phytoremediation technology

Light Emitting Diodes (LEDs) have emerged as a tool with great potential in the field of phytoremediation, offering a novel approach to enhance the efficiency of plant-based remediation techniques. In this work investigated the influence of LEDs on the phytoremediation of arsenic (As) and mercury (Hg) by Ceratophyllum demersum L., propagated using tissue culture methods. In addition, the biochemical properties of the plants exposed to metal toxicity were examined. Phytoremediation experiments employed concentrations of As (0.01–1.0 mg/L) and Hg (0.002–0.2 mg/L), with application periods set at 1, 7, 14, and 21 days. In addition to white, red and blue LEDs, white fluorescent light was used for control purposes in the investigations. A positive correlation was observed between higher metal concentrations, extended exposure times, and increased metal accumulation in the plants. Red LED light yielded the highest level of heavy metal accumulation, while white fluorescent light resulted in the lowest accumulation level. Examination of the biochemical parameters of the plants, including photosynthetic pigment levels, protein quantities, and lipid peroxidation, revealed a pronouncedly enhanced performance in specimens subjected to red and blue LED illumination, surpassing outcomes observed in other light treatments. The findings of this study introduce innovative avenues for the effective utilization of red and blue LED lights in the realm of phytoremediation research. Thus, the interaction between LEDs, tissue culture, and the phytoremediation process could lead to synergistic effects that contribute to more effective and sustainable remediation strategies.

Accelerated failure time modeling of in-lane street hawkers’ lane entry and exit behaviors at signalized intersections

In-lane street hawking is the intermittent entry of signalized intersections by traders to sell groceries to drivers and passengers. Studies have shown that hawkers get exposed to traffic injuries but the lack of quantitative analysis of their lane entry and exit behaviors in signalized intersections makes it difficult to improve traffic safety. This study analyzes the significant predictors of in-lane street hawkers’ (1) lane entry within 30 s after the red signal illumination, (2) lane exit within 30 s after the green signal illumination, and (3) probability of getting injuries during the green signal time. Drone-based trajectory data were collected from a selected signalized intersection in Accra, Ghana. A Weibull accelerated failure time duration model incorporating Gamma frailty was used to evaluate hawkers’ behaviors. Overall, the majority of hawkers exhibited red-light running behaviors exposing them to traffic injuries. An increase in traffic speed, especially beyond 20 km/h, exposed hawkers to injury risks significantly. Notably, hawkers’ lane entry decreased significantly as the traffic speed increased. Their lane exit duration was significantly predicted by the queue lengths and traffic volumes. Accordingly, safety practitioners can enhance traffic regulation and control methods in addition to pro-poor social interventions to demotivate hawking at signalized intersections.

Chromatic changes in vision with diffractive ophthalmic optics.

Diffractive optics is a valuable technique for designing presbyopia-correcting lenses, but its effectiveness is wavelength-dependent. This study investigates the spatio-chromatic alterations in visual resolution associated with diffractive multifocal lenses by using non-invasive, removable diffractive bifocal contact lenses. The study combines theoretical analysis, numerical simulation, and clinical intra-observer experiments to assess visual acuity under various lighting conditions. Results demonstrate the introduction of spatio-chromatic asymmetry and a change in visual acuity under red and blue lights, depending on the operating diffraction order employed in the lens design. The energy distribution of the diffractive contact lens studied favors resolution under red illumination at far distances and under blue illumination at near distances. These findings are consistent with computational simulations and provide insights into the visual changes induced by diffractive ophthalmic lenses.

A visual measurement method of grinding surface roughness based on aliasing region index and neural network

Most existing vision-based roughness measurements primarily rely on statistical information from grayscale images or intensity information from color images. However, the structural information of images has not been fully and effectively utilized. To more accurately measure the roughness of grinding surfaces, a visual measurement method of grinding surface roughness based on aliasing region index and neural network is proposed. Firstly, color images of grinding surface are obtained under red and green illumination. Secondly, aliasing regions of red and green images are extracted through fuzzy clustering segmentation and morphological processing. Then the aliasing width and the aliasing dispersion of aliasing region can be calculated as indices for roughness measurement. Thirdly, the relationship model between aliasing region index and grinding surface roughness is constructed using the back propagation (BP) neural network. The results demonstrate that the aliasing dispersion index has a better correlation with grinding surface roughness than the aliasing width index. The method based on the aliasing dispersion index and BP neural network is feasible and accurate for grinding surface roughness measurement.

The effect of yellow and red illuminations on the swimming behaviour, mortality and growth rates of yellowfin tuna juveniles (Thunnus albacares)

The effect of yellow and red illuminations on the swimming behaviour, mortality and growth rates of yellowfin tuna juveniles (<i>Thunnus albacares</i>)

BOLD fMRI in patients before and after multifocal intraocular lens implantation

Background. In practical ophthalmology during cataract surgery, patients are increasingly being implanted with multifocal intraocular lenses (mfIOLs), which form several foci on the retina. The appearing of new factors creates conditions for human neuroadaptation, the parameters of which can be assessed using a modern research method – functional magnetic resonance imaging (fMRI). Purpose: to determine the change in the nature of the activation of the visual brain cortex in response to stimulation after surgery for the implantation of a multifocal artifi cial lens. Materials and methods. The study included patients with cataract (n = 22), who underwent structural neuroimaging and BOLD fMRI to assess neuronal activity before and after mfIOL implantation. The Gabor element was used as a stimulus for performing BOLD fMRI (unilluminated and ill uminated versions). fMRI data (positive BOLD effect) were processed using the SPM 12 software package in the Matlab R2017a environment. Evaluation of the research results was carried out at the individual and group levels. Results. When evaluating individual results after mfIOL implantation, patients show more local activation of the cerebral cortex, gravitating towards the area of the spur sulcus, while before surgery, the cortical response is more diffuse. In a group analysis in patients after mfIOL implantation, the total volume of the activation cluster of the cerebral cortex signifi cantly increased by 27 times. Maximum activation is noted in the pulvinar on the right and the lingual gyrus on the left. The activation of the cortex in the study with red illumination of Gabor element after surgery is less than in the study with white illumination, and less than in the study after surgery without illumination of Gabor element. Conclusions. A signifi cant but ambiguous change in the neuronal activity of the cerebral cortex on various stimulation options in patients after mfIOL implantation was established. Further work in this area is planned

Seeing green: phototactic responses for management of Rove beetle Paederus fuscipes

Paederus fuscipes Curtis (Coleoptera: Staphylinidae) is a medical pest due to its attraction to bright light sources from human residential premises. This study aims to investigate the phototactic response on light wavelengths and colour preferences by P. fuscipes. Paedarus fuscipes showed positive responses to all types of light sources (fluorescent, LED, and incandescent) presented in the light and dark choice test, which indicates their attractiveness towards light presented in human habitation. However, most beetles showed a higher preference towards fluorescent and cool white LED. Paedarus fuscipes showed consistent preferences for white, blue and green, with the exception of red. Remarkably, green light elicited the strongest positive phototactic response compared to other colours. Overall, our results showed that P. fuscipes beetles prefer the range of 550 nm wavelength. Warm light colours such as yellow (warm white LED) with red illumination can be recommended to avoid infestation and in innovative management of Paedarus.

Fully Implantable and Retrievable Upconversion Waveguides for Photodynamic Therapy in Deep Tissue

AbstractThe clinical administration of biophotonic approaches, such as photodynamic therapy (PDT), is impeded by the low penetration of visible light in biological tissues. The cooperation of infrared (IR) light with deeper penetration and implantable IR‐to‐visible upconversion materials and devices establishes an effective strategy to generate visible light in deep tissue. In this work, a wirelessly powered upconversion waveguide‐based light source is reported for PDT‐based in vivo cancer treatments in deep tissue. Combining microscale IR‐to‐visible upconversion device arrays and a biocompatible waveguide, the implant exhibits enhanced IR transmission in biological environments and generates upconverted red emission in the target region at a depth &gt;10 mm. The red illumination activates a photosensitizer in 5‐aminolevulinic acid (5‐ALA)‐based PDT treatment, inducing massive apoptosis (&gt;60% cell death) of tumor cells. After implanted in tumor‐bearing mice, the waveguides enable chronic operation for more than two weeks and reveal ideal anti‐tumor efficacies in the PDT process. Finally, the biocompatible waveguide can be retrieved from the tissue, leaving minimal traces after treatments. Such a waveguide implant represents a prospective technique to realize optical‐based biological modulations and medical treatments within the body.

Photoredox-active Cr(0) luminophores featuring photophysical properties competitive with Ru(II) and Os(II) complexes

Coordination complexes of precious metals with the d6 valence electron configuration such as Ru(II), Os(II) and Ir(III) are used for lighting applications, solar energy conversion and photocatalysis. Until now, d6 complexes made from abundant first-row transition metals with competitive photophysical and photochemical properties have been elusive. While previous research efforts focused mostly on Fe(II), we disclose that isoelectronic Cr(0) gives access to higher photoluminescence quantum yields and excited-state lifetimes when compared with any other first-row d6 metal complex reported so far. The luminescence behaviour of the metal-to-ligand charge transfer excited states of these Cr(0) complexes is competitive with Os(II) polypyridines. With these Cr(0) complexes, the metal-to-ligand charge transfer states of first-row d6 metal complexes become exploitable in photoredox catalysis, and benchmark chemical reductions proceed efficiently under low-energy red illumination. Here we demonstrate that appropriate molecular design strategies open up new perspectives for photophysics and photochemistry with abundant first-row d6 metals.

Efficient tunable temperature sensitivity in thermally coupled levels of Er3+/Yb3+ co-doped BaBi2Nb2O9 ferroelectric ceramic

Er3+/Yb3+ co-doped ferroelectric ceramic BaBi2-0.04-yNb2Er0.04YbyO9 (y = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, and 0.12) are prepared by solid-state method and investigated for their structural and upconversion luminescence properties. High-resolution X-ray pattern investigation confirmed the ceramic's orthorhombic structure. Microstructure of sintered ceramic surface resembles plate-like structures and consists of non-uniform grains that are randomly oriented. Upconversion luminescence (UCL) spectra revealed two prominent green emission bands near 535 and 557 nm and a notable red band at 672 nm, corresponding to a 980 nm excitation wavelength. Decay time measurements support the effective energy transfer from Yb3+ to Er3+ ions. The average lifetime increases with increasing Er3+/Yb3+ doping concentration up to the optimal concentration (y = 0.10). Pump power dependence demonstrates that two photons are required to generate green and red UC illumination. The absolute sensitivity, Sa (0.69% K−1 and 0.58% K−1) and relative sensitivity, Sr (1.1% K−1 and 1.01% K−1) have been recorded for the first time on Er3+/Yb3+ co-doped BaBi2-0.04-yNb2Er0.04YbyO9 ceramic at y = 0.06 and 0.10, respectively, suggesting it is a viable non-contact sensor ceramic whose sensitivity can be tuned by varying dopant concentrations.

Whole-transcriptome RNA sequencing reveals changes in amino acid metabolism induced in harvested broccoli by red LED irradiation

Whole-transcriptomic profiling combined with amino acid analysis were conducted in order to gain a better understanding of global changes in amino acid metabolism induced in broccoli by red LED irradiation. The results showed that the contents of almost all 16 amino acids in postharvest broccoli were maintained under red LED illumination. The red LED irradiation enhanced the anabolism of amino acid, including the biosynthesis of aromatic amino acids by upregulating the genes’ expression in the shikimate pathway, as well as by upregulating the genes’ expression which encoding biosynthetic enzymes in the branched-chain amino acid biosynthesis pathway. Red LED irradiation induced the expression of genes encoding aspartate aminotransferase, which plays a role in Asp synthesis, aspartate kinase, which functions in aspartate metabolism, and a cytoplasmic aspartate aminotransferase that converts 2-Oxoglutarate into Glu. Genes encoding imidazole glycerol-phosphate synthase and histidinol-phosphatase, which function in the His biosynthesis pathway, were also upregulated. According to our results, red LED irradiation delays broccoli’s yellowing and senescence by regulating amino acid metabolism. These results enhance our understanding of the role of amino acid metabolism in the senescence of broccoli and the mechanism of red LED irradiation to alter amino acid metabolism in harvested broccoli.

Pulse Oximetry Imaging System Using Spatially Uniform Dual Wavelength Illumination.

Pulse oximetry is a non-invasive method for measuring blood oxygen saturation. However, its detection scheme heavily relies on single-point measurements. If the oxygen saturation is measured at a single location, the measurements are influenced by the profile of illumination, spatial variations in blood flow, and skin pigment. To overcome these issues, imaging systems that measure the distribution of oxygen saturation have been demonstrated. However, previous imaging systems have relied on red and near-infrared illuminations with different profiles, resulting in inconsistent ratios between transmitted red and near-infrared light over space. Such inconsistent ratios can introduce fundamental errors when calculating the spatial distribution of oxygen saturation. In this study, we developed a novel illumination system specifically designed for a pulse oximetry imaging system. For the illumination system, we customized the integrating sphere by coating a mixture of barium sulfate and white paint inside it and by coupling eight red and eight near-infrared LEDs. The illumination system created identical patterns of red and near-infrared illuminations that were spatially uniform. This allowed the ratio between transmitted red and near-infrared light to be consistent over space, enabling the calculation of the spatial distribution of oxygen saturation. We believe our developed pulse oximetry imaging system can be used to obtain spatial information on blood oxygen saturation that provides insight into the oxygenation of the blood contained within the peripheral region of the tissue.

Abstract 4707: LED photobleaching-based multiplex 3D microscopy of the tumor microenvironment

Abstract Multiplexing in immunofluorescence imaging is important for the spatial profiling of cells and molecules in tumor tissue samples. Cyclic immunofluorescence (IF) methods using oxidants (e.g. hydrogen peroxide) and enzymes (e.g. DNase) localize a great number of cellular makers and proteins in a tissue section while repeating a process of IF staining, imaging, and fluorescence deactivation. However, the repeated use of chemicals and enzymes might cause artifacts in tissue and cell morphologies. Furthermore, these methods are restricted to thin tissue sections (~5 μm thick) which are inappropriate to provide comprehensive structural information on tissue samples. Although reconstruction of two-dimensional (2D) images from serial tissue sections can provide a certain volumetric tissue image, it takes a huge amount of time and effort. Here we introduce a three-dimensional (3D) multiplex IF imaging method using LED photobleaching. We built high-power LED illuminators with 100W warm (emission wavelength: 480-700 nm), green (430-520 nm), and red (600- 680 nm) LED chips, which can efficiently bleach a broad or selected wavelength of fluorescence signals in tissue samples. We integrated this LED photobleaching with the Transparent Tissue Tomography (T3) protocol and created a 3D cyclic IF method involving tissue macrosectioning (400 μm), three-color IF staining, D-fructose-based tissue clearing, 3D confocal fluorescence microscopy, LED photobleaching, tissue washing, and three-color IF staining for other biomarkers, and repeating the process. By applying this method to mouse mammary tumor tissues, we could perform 8-plex fluorescence microscopy for visualizing cell nuclei (DAPI), vascular (CD31, SMA) and structural (ER-TR7) cells, immune cells (CD3, CD8, CD45), and cancer cells (CK8) in the tumor macrosections in 3D at tissue and cellular resolution. To validate the method as an evaluation tool for immunotherapy, we treated the mouse mammary tumor with a STING agonist (DMAXX) intratumorally and collected the tumor tissue 1 day after the treatment, and processed it for the 3D cyclic IF protocol. The quantitative multiplex image data showed immune-driven-cancer eradication and high tumor infiltration of a large number of CD3+CD8+CD45+ cytotoxic T cells. We also examined that Red and Green LED illumination can selectively bleach fluorophores in tissues, which would be useful for patterning fluorescence in tissue as well as studying fluorescent drug-cell interaction in a tissue. In summary, this chemical and enzyme-free 3D cyclic IF imaging method will be a powerful tissue assay tool to provide comprehensive spatial information of tissue (tumor) samples including cell types, cellular and molecular location, and their 3D organization in a tissue sample. Citation Format: Jingtian Zheng, Evan Phillips, Yi-Chien Wu, Steve Seung-Young Lee, Vytautas Bindokas. LED photobleaching-based multiplex 3D microscopy of the tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4707.

All-Optical Switching Based on Sub-Bandgap Photoactivation of Charge Trapping in Metal Halide Perovskites.

Controllable optical properties are crucial for the application of light-emitting materials in optical devices. In this work, controllable photoluminescence in metal halide perovskite crystals is realized via photoactivation of their defects. It is found that under continuous excitation, the photoluminescence intensity of a CH3 NH3 PbBr3 crystal can be fully controlled by sub-bandgap energy photon illumination. Such optically controllable emission behavior is rather general as it is observed also in CsPbBr3 and other perovskite materials. The switching mechanism is assigned to reversible light-induced activation/deactivation of nonradiative recombination centers, the presence of which relates to an excess of Pb during perovskite synthesis. Given the success of perovskites in photovoltaics and optoelectronics, it is believed that the discovery of green luminescence controlled by red illumination will extend the application scope of perovskites toward optical devices and intelligent control.

Scanning Electrochemical Microscope Studies of Charge Transfer Kinetics at the Interface of the Perovskite/Hole Transport Layer

Interfacial carrier transfer kinetics is critical to the efficiency and stability of perovskite solar cells. Herein, we measure the regeneration rate constant, absorption cross-section, reduction rate constant, and conductivity of hole transport layered perovskites using scanning electrochemical microscopy (SECM). The SECM feedback revealed that the regeneration rate constant, absorption cross-section, and reduction rate constant of the nickel oxide (NiO) layer perovskite layer are higher than those of the poly (3,4-ethyenedioxythiophene)-poly (styrenesulfonate) layered perovskite. Also, at a specific flux density ( J h v ), the value of the regeneration rate constant (keff) in both blue and red illuminations for the NiO/CH3NH3PbI3 film is significantly higher than in both PEDOT: PSS/CH3NH3PbI3 and FTO/CH3NH3PbI3 films. The difference in keff between layered and nonlayered perovskite conforms to the impact of the hole conducting layer on the charge transfer kinetics. According to the findings, SECM is a powerful approach for screening an appropriate hole transport layer for stable perovskite solar cells.

Effects of Spirulina maxima on a Model of Sexual Dysfunction in Streptozotocin-Induced Diabetic Male Rats

Arthrospira (Spirulina) maxima (SM) is a cyanobacterium that has a long history of being used as human food. In recent years, several investigations have shown its beneficial biological effects, among which its antioxidant capacity has been highlighted. The purpose of this study was to evaluate the effects of SM on body weight, glycemia, sexual behavior, sperm quality, testosterone levels, sex organ weights, and the activity of antioxidant enzymes in diabetic male rats (a disease characterized by an increase in reactive oxygen species). The experiment consisted of six groups of sexually expert adult males (n = 6): (1) control (vehicle); (2) streptozotocin (STZ)-65 mg/kg; (3) SM-400 mg/kg; (4) STZ + SM-100 mg/kg; (5) STZ + SM-200 mg/kg; and (6) STZ + SM-400 mg/kg. Sexual behavior tests were performed during the first 3 h of the dark period under dim red illumination. Our results showed that SM significantly improved sexual behavior and sperm quality vs. diabetic animals. Likewise, while the enzymatic activities of SOD and GPx increased, TBARS lipoperoxidation decreased and testosterone levels increased. In view of the findings, it is suggested that SM may potentially be used as a nutraceutical for the treatment of diabetic male sexual dysfunction due to its antioxidant property.

Room-Temperature Photochromism of Silicon Vacancy Centers in CVD Diamond.

The silicon vacancy (SiV) center in diamond is typically found in three stable charge states, SiV0, SiV-, and SiV2-, but studying the processes leading to their formation is challenging, especially at room temperature, due to their starkly different photoluminescence rates. Here, we use confocal fluorescence microscopy to activate and probe charge interconversion between all three charge states under ambient conditions. In particular, we witness the formation of SiV0 via the two-step capture of diffusing, photogenerated holes, a process we expose both through direct SiV0 fluorescence measurements at low temperatures and confocal microscopy observations in the presence of externally applied electric fields. In addition, we show that continuous red illumination induces the converse process, first transforming SiV0 into SiV- and then into SiV2-. Our results shed light on the charge dynamics of SiV and promise opportunities for nanoscale sensing and quantum information processing.

Reproductive Performance of Zi-Goose Promoted by Red Color Illumination.

The color of light affects the reproductive performance of poultry, but it is not clear what efficient illumination strategy could be adopted to improve the reproductive performance of Zi-goose. Red light can increase the average weekly egg production rate, egg production, and qualified production. It can increase the serum GnRH level and decrease the serum PRL, MT, and T4 levels. In our study, red light for 12 h increased the average weekly laying rate, average qualified egg production, and hatching rate of Zi-goose eggs, and increased the serum levels of FSH, LH, P4, E2, MT, T3, and T4. Blue light at 14 h improved the average weekly egg production rate, average egg production, and average qualified egg production, and reduce serum PRL and MT levels to ensure the improvement of reproductive performance of goose. A total of 705,714 overlapping group sequences, 471,145 transcript sequences, and 268,609 single gene sequences were obtained from 18 sequencing samples, with a total length of 323.04, 668.53, and 247.88 M, respectively. About 176,416 unigenes were annotated successfully in six databases, accounting for 65.68% of the total unigenes obtained. 2,106, 2,142, and 8,892 unigenes were identified in the hypothalamus, pituitary gland, and ovary of the birds respectively, with different expressions of light regulation. The hypothalamus, ovary, and pituitary were involved in 279, 327, and 275 KEGG (Kyoto Encyclopedia of Genes and Genomes) metabolic pathways in response to light, respectively. Through further significance analysis and differential discovery rate control, a total of five metabolic pathways were obtained which were closely related to the reproductive hormones of goose. Ten candidate genes related to the reproductive performance of goslings were selected according to the identification results of differentially expressed genes of goslings under red light and white light conditions and the genes involved in metabolic pathways significantly related to the reproductive hormones of goslings. The expression levels of GnRh-1 in the hypothalamus, GnRH-R, FSH β and LH β in the pituitary gland, and FSH-R and LH-R candidate genes in the ovary were higher under the 12 h red light treatment than white light. However, the expression levels of VIP, PRL, and PRL-R candidate genes in the hypothalamus, pituitary and ovary were lower under 12 h red light than under 12 h white light.