Short-wavelength Light Research Articles

Dichromacy in the brown marmorated stink bug? Spectral sensitivity of the compound eyes and phototaxis of Halyomorpha halys

AbstractThe brown marmorated stink bug (Halyomorpha halys) is an invasive pest insect species, which was recently introduced from Asia to America and then to Europe. Besides causing serious damage in agriculture, this species also represents a source of intense annoyance for humans in residential areas, because large amounts of individuals can aggregate on buildings while seeking shelter before overwintering. Taking into account the need for pesticide-free pest management methods, for example light trapping, we measured the spectral sensitivity of the compound eyes of H. halys with electroretinography (ERG). In behavioural experiments, we also quantified the attraction of H. halys to 14 quasi-monochromatic light stimuli in the 368–743 nm spectral range. The dark-adapted compound eyes were mostly sensitive to the green range, but a minor sensitivity peak in the UV region was also identified. Recordings on chromatic-adapted eye preparations unequivocally revealed the presence of only a green- and a UV-sensitive photoreceptor type, with sensitivity maxima at 519 nm and 367 nm, respectively. No sign of any blue-sensitive receptor was detected, and thus only a receptor set allowing dichromatic vision was found. Based on the results of the behavioural experiments, we established that the attraction of H. halys to light is increasing with decreasing wavelength, and thus we emphasize the importance of short wavelength lights (368–455 nm) when phototactic attraction of H. halys is the aim.

Behavioural responses of cockroaches <i>Periplaneta americana</i> L. to short and long wavelength light in a wind tunnel

The behavioural responses of the American cockroach Periplaneta americana to short-wavelength and long-wavelength light were studied in a wind tunnel. Initial directional movement towards the light source was observed in response to both stimuli, but the latency in response to green light was significantly shorter. The cockroaches moving towards the UV light often returned to the less illuminated starting point, while this behaviour was not typical under green light. UV light often initiated masking, the behavior characteristic of the inactive, diurnal phase of the 24-hour cycle.

Nuclear Receptor Subfamily 2 Group E Member 3 (NR2E3): Role in Retinal Development and Disease.

NR2E3 is a nuclear hormone receptor gene required for the correct development of the retinal rod photoreceptors. Expression of NR2E3 protein in rod cell precursors suppresses cone-specific gene expression and, in concert with other transcription factors including NRL, activates the expression of rod-specific genes. Pathogenic variants involving NR2E3 cause a spectrum of retinopathies, including enhanced S-cone syndrome, Goldmann-Favre syndrome, retinitis pigmentosa, and clumped pigmentary retinal degeneration, with limited evidence of genotype-phenotype correlations. A common feature of NR2E3-related disease is an abnormally high number of cone photoreceptors that are sensitive to short wavelength light, the S-cones. This characteristic has been supported by mouse studies, which have also revealed that loss of Nr2e3 function causes photoreceptors to develop as cells that are intermediate between rods and cones. While there is currently no available cure for NR2E3-related retinopathies, there are a number of emerging therapeutic strategies under investigation, including the use of viral gene therapy and gene editing, that have shown promise for the future treatment of patients with NR2E3 variants and other inherited retinal diseases. This review provides a detailed overview of the current understanding of the role of NR2E3 in normal development and disease, and the associated clinical phenotypes, animal models, and therapeutic studies.

Fundus autofluorescence imaging using red excitation light

Retinal disease accounts significantly for visual impairment and blindness. An important role in the pathophysiology of retinal disease and aging is attributed to lipofuscin, a complex of fluorescent metabolites. Fundus autofluorescence (AF) imaging allows non-invasive mapping of lipofuscin and is a key technology to diagnose and monitor retinal disease. However, currently used short-wavelength (SW) excitation light has several limitations, including glare and discomfort during image acquisition, reduced image quality in case of lens opacities, limited visualization of the central retina, and potential retinal light toxicity. Here, we establish a novel imaging modality which uses red excitation light (R-AF) and overcomes these drawbacks. R-AF images are high-quality, high-contrast fundus images and image interpretation may build on clinical experience due to similar appearance of pathology as on SW-AF images. Additionally, R-AF images may uncover disease features that previously remained undetected. The R-AF signal increases with higher abundance of lipofuscin and does not depend on photopigment bleaching or on the amount of macular pigment. Improved patient comfort, limited effect of cataract on image quality, and lack of safety concerns qualify R-AF for routine clinical monitoring, e.g. for patients with age-related macular degeneration, Stargardt disease, or for quantitative analysis of AF signal intensity.

Controllable synthesis of blue-emitting CsPbBr3 nanoplates via a SnBr2-mediated solvothermal reaction method

Blue-emitting CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) have potential applications in white light illumination and full-color luminescent displays. However, current methods for synthesizing blue-emitting CsPbX3 NCs face challenges in poor controllability, low photoluminescence quantum yields (PLQYs), and the harmful effects of short-wavelength blue light. In this work, we report on a SnBr2-mediated solvothermal method for the controllable synthesis of blue-emitting CsPbBr3 nanoplates (NPLs) that exhibit high optical purity within the harmless blue light range. The pioneering use of SnBr2 as a mediator in solvothermal reactions plays a crucial role in the controllable synthesis process. By increasing the amount of SnBr2, the as-prepared products gradually transform from CsPbBr3 NCs to mixed CsPbBr3/Cs4PbBr6 NCs, and finally to CsPbBr3 NPLs. By further adjusting the solvothermal reaction conditions, CsPbBr3 NPLs with controlled thickness (2.34–3.53 nm), regulated blue-light emission (459.4–466.6 nm) and a high PLQY up to 63.17% can be obtained. This study provides a feasible method for the controllable synthesis of perovskite NPLs and opens up new possibilities for the application of perovskite blue light-emitting devices.

Emission and optical characteristics of brown carbon in size-segregated particles from three types of Chinese ships

Brown carbon (BrC) is one of the important light absorption substances that have high light absorption ability under short wavelength light. However, limit studies have focused on the BrC emission from ships. In this study, size-segregated particulate matters (PM) were collected from three different types of ships, light absorption characteristics and size distribution of methanol-soluble BrC and water-soluble BrC in PM from ship exhausts were investigated. Results showed that four-stroke low-power diesel fishing boat (4-LDF) had the highest mass concentrations of methanol-soluble organic carbon (MSOC) and water-soluble organic carbon (WSOC), followed by 2-stroke high-power heavy-fuel-oil vessel (2-HHV), and four-stroke high-power marine-diesel vessel (4-HMV). While 2-HHV had obviously higher light absorption coefficients of methanol-soluble BrC (Abs365,M) and water-soluble BrC (Abs365,W) in unit weight of PM than the other two types of ships. The tested ships presented comparable or higher absorption efficiency of BrC in water extracts (MAE365,W) compared with other BrC emission sources. Majority of BrC was concentrated in fine particles, and the particle size distributions of both Abs365,M and Abs365,W showed bimodal patterns, peaking at 0.43–0.65 µm and 4.7–5.8 µm, respectively. However, different particle size distributions were found for MAE365,M between diesel and heavy fuel oil ships. Besides, different wavelength dependence in particles with different size were also detected. Ship exhaust could be confirmed as a non-ignorable BrC emission source, and complex influencing factor could affect the light absorption characteristics of ship emissions. Particle size should also be considered when light absorption ability of BrC was evaluated.

Examination of the effects of blue light stress on monoamine oxidase-mediated immunomodulatory function in the Pacific abalone, Haliotis discus hannai

Marine environments harbor a growing number of stressors brought about by global climate change, local human activities and the urbanization of coastal areas. The Pacific abalone, Haliotis discus hannai, is a nocturnal animal that avoids strong light and prefers darkness. Previous research showed that the abalone mortality rate under short-wavelength blue light was remarkably greater than that under darkness, natural light and orange light. In this study, the temporal variations in the dopamine content of abalone hemolymph under various light conditions were compared, and the dopamine content after exposure to blue light for 6 h was remarkably higher than that in any other group. The full-length monoamine oxidase (MAO) gene sequence for the catecholamine metabolism-related MAO enzyme was obtained by cloning. This gene encoded 545 amino acids, in which the predicted sequence contained a domain that was characteristic for monoamino oxidase. The MAO expression levels were highest in the hepatopancreas and in situ hybridization further revealed that MAO was widely localized around the hepatic nerve cord. The in vitro recombinant MAO protein could catalyze the degradation of epinephrine and dopamine. After 3 h exposure to blue light, the expression levels of MAO, Mn-superoxide dismutase (Mn-SOD), and catalase (CAT) genes were remarkably greater than those in any other group, but the lysozyme (LYZ) and sigma-glutathione-s-transferase (GSTs) expression levels began to increase at 12 h and 6 h, respectively. After the MAO expression levels were knocked-down by RNAi technology, the dopamine concentration significantly increased, but the phagocytic activity, nitric oxide concentration, and the Mn-SOD, CAT, GSTs and LYZ expression levels were remarakbly lower than in the control group and the enhanced green fluorescent protein (GFP) group, suggesting that the normal dopamine metabolism process played a vital role in maintaining the immune response. The above results show that monoamine oxidase may act as an immunomodulator in abalone when responding to adverse light conditions. These results could also be useful when drawing up conservation measures for preserving nearshore benthic biodiversity, such as optimizing urban night lighting schemes.

Unification of Irreversibility and Energy Diagram Theory.

A simultaneous emission-detection phenomenon occurs when a quantum well (QW) diode is biased with a forward voltage and illuminated with a shorter-wavelength light beam. The diode is able to detect and modulate light emitted by itself due to its spectral emission-detection overlap. Here, two identical QW diode units separately function as a transmitter and a receiver to establish a wireless light communication system. In association with energy diagram theory, we explain the irreversibility between light emission and light excitation in the QW diode, which may help us deeply understand various expressions in nature.

Drosophila photoreceptor systems converge in arousal neurons and confer light responsive robustness.

Lateral ventral neurons (LNvs) in the fly circadian neural circuit mediate behaviors other than clock resetting, including light-activated acute arousal. Converging sensory inputs often confer functional redundancy. The LNvs have three distinct light input pathways: (1) cell autonomously expressed cryptochrome (CRY), (2) rhodopsin 7 (Rh7), and (3) synaptic inputs from the eyes and other external photoreceptors that express opsins and CRY. We explored the relative photoelectrical and behavioral input contributions of these three photoreceptor systems to determine their functional impact in flies. Patch-clamp electrophysiology measuring light evoked firing frequency (FF) was performed on large LNvs (l-LNvs) in response to UV (365 nm), violet (405 nm), blue (450 nm), or red (635 nm) LED light stimulation, testing controls versus mutants that lack photoreceptor inputs gl60j, cry-null, rh7-null, and double mutant gl60j-cry-null flies. For UV, violet, and blue short wavelength light inputs, all photoreceptor mutants show significantly attenuated action potential FF responses measured in the l-LNv. In contrast, red light FF responses are only significantly attenuated in double mutant gl60j-cry-null flies. We used a light-pulse arousal assay to compare behavioral responses to UV, violet, blue and red light of control and light input mutants, measuring the awakening arousal response of flies during subjective nighttime at two different intensities to capture potential threshold differences (10 and 400 μW/cm2). The light arousal behavioral results are similar to the electrophysiological results, showing significant attenuation of behavioral light responses for mutants compared to control. These results show that the different LNv convergent photoreceptor systems are integrated and together confer functional redundancy for light evoked behavioral arousal.

Design and manufacturing of aspherical GaAs-SILs for a versatile optical semiconductor failure analysis system

In this study, we have developed an aspherical solid immersion lens (SIL) made of gallium arsenide (GaAs) for semiconductor failure analysis. A SIL is an optical component to dramatically increase the numerical aperture and the spatial resolution of a microscopy system by attaching it to the backside of the device-under-test. To further enhance the spatial resolution of the optical microscopy system, a shorter wavelength light source has also been introduced. In the past, we have developed a spherical SIL made of silicon (Si), which is the same material as the device under test. However, Si is not transparent for wavelengths shorter than around 1100 nm. To enable the use of a SIL at shorter wavelengths, we chose GaAs as SIL material, which is transparent at shorter wavelengths than Si and has a refractive index very close to that of Si. However, a spherical GaAs SIL features a more pronounced spherical aberration due to the difference in refractive index between the device-under-test (Si) and that of the SIL (GaAs) deteriorating the optical resolution of the microscopy system. We have therefore designed an aspherical GaAs-SIL which makes it possible to correct spherical aberration. We applied diamond tooling as a technique for manufacturing the SIL shape with a required surface irregularity below 100 nm peak-to-valley, resulting in a diffraction limited performance of the optical system for semiconductor failure analysis with a performance at around 0.18 μm cutoff.

Near-Infrared Light-Activated Ruthenium Complex-based Photocage for Cancer Phototherapy.

Conventional photocages only respond to short wavelength light, which is a significant obstacle to developing efficient phototherapy in vivo. The development of photocages activated by near-infrared (NIR) light at wavelengths from 700 to 950 nm is important for in vivo studies but remains challenging. Herein, we describe the synthesis of a photocage based on a ruthenium (Ru) complex with NIR light-triggered photocleavage reaction. The commercial anticancer drug, tetrahydrocurcumin (THC), was coordinated to the Ru(II) center to create the Ru-based photocage that is readily responsive to NIR light at 760 nm. The photocage inherited the anticancer properties of THC. As a proof-of-concept, we further engineered a self-assembled photocage-based nanoparticle system with amphiphilic block copolymers. Upon exposure to NIR light at 760 nm, the Ru complex-based photocages were released from the polymeric nanoparticles and efficiently inhibited tumor proliferation in vivo.

A Near‐Infrared Light‐Activated Photocage Based on a Ruthenium Complex for Cancer Phototherapy

AbstractConventional photocages only respond to short wavelength light, which is a significant obstacle to developing efficient phototherapy in vivo. The development of photocages activated by near‐infrared (NIR) light at wavelengths from 700 to 950 nm is important for in vivo studies but remains challenging. Herein, we describe the synthesis of a photocage based on a ruthenium (Ru) complex with NIR light‐triggered photocleavage reaction. The commercial anticancer drug, tetrahydrocurcumin (THC), was coordinated to the RuII center to create the Ru‐based photocage that is readily responsive to NIR light at 760 nm. The photocage inherited the anticancer properties of THC. As a proof‐of‐concept, we further engineered a self‐assembled photocage‐based nanoparticle system with amphiphilic block copolymers. Upon exposure to NIR light at 760 nm, the Ru complex‐based photocages were released from the polymeric nanoparticles and efficiently inhibited tumor proliferation in vivo.

The response of adult adzuki been borer <i>Ostrinia scapulalis</i> to light stimuli in a wind tunnel

The attraction of nocturnal insects to light is a known phenomenon with unknown physiological mechanisms. Moths of the pyralid family are characterized by the most pronounced response to light, but the spectral preferences of these insects have not been studied. The adzuki been borers Ostrinia scapulalis, which live on dicotyledonous plants, are the ancestral form for the Asian and European corn borers, widespread pests of corn. Using a wind tunnel modified to deliver light stimuli, we tested the responses of males and females to light stimuli with wavelengths of 532, 440 and 365 nm at 2 lux, capable of stimulating photoreceptors of compound eyes (with maximum sensitivity of 352, 413, 480 and 530 nm) as well as simple ocelli, whose sensitivity had the main peak in ultraviolet and additional one in the green spectrum (360 and 520 nm). It turned out that ultraviolet was the most attractive stimulus. A small percentage of insects responded to green light, but showed a freezing reaction near the light source. The least attractive was blue light, which also caused freezes. Thus, the flight of O. scapulalis adults is induced by short-wavelength light, the response is more consistent with the sensitivity of the ocelli than the compound eyes; blue and green light leads to a masking effect.

Visible to Mid-Infrared Photodetector Based on Black Phosphorous-MoS2 Van Der Waals Heterojunction

Van der Waals heterostructures of black phosphorous(BP) and Molybdenum Disulfide(MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) is designed and evaluated for photodetection application from visible to mid-infrared wavelength up to 4.5 μm. The device possesses a low dark current less than 0.1 μA for short wavelength light. For visible and near infrared radiation, the contribution of heat and photo energy to current enhancement is analyzed. Dark current drift by joule heat and laser heat absorbed is observed in short waveband. The difference in response speed is believed to be a result of the competition of BP and MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> photocurrent. Gate tunable response time and on-off ratio makes the device versatile in potential application. For mid infrared radiation, BP-MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> heterojunction with a dedicated thickness tailoring of MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> exhibits similar negative response as an intrinsic BP. The normalized detectivity is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${D}^*$</tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2.02 \times {10}^8\ Jones$</tex-math></inline-formula> for the 4.5 μm mid-infrared radiation. Elaborate reduction of the noise is conducted to get the time resolvable photo-response. A low bias is necessary for a time resolved photocurrent, reducing the flicker noise to an acceptable level.

Simultaneous light emission and detection of an AlGaInP quantum well diode

When a quantum well (QW) diode is biased with a forward voltage and illuminated with an external shorter-wavelength light, the device simultaneously emits and detects light, with the injected current and the induced current mixed inside the wells. Separating these superimposed and dynamic electrical signals is useful for the development of multifunctional displays that can simultaneously transmit and receive light signals. By utilizing the unique overlap between the electroluminescence and detection spectra, we establish a wireless optical communication system using two AlGaInP diodes that have identical QW structures. The communication distance is 25 m, with one diode functioning as the transmitter and the other as the receiver. In particular, at the receiver end, the QW diode demonstrates simultaneous light emission and reception ability, and the mixed signals can be efficiently extracted, suggesting great potential for applications from light communication to advanced displays.

A novel instrument to determine hue discrimination.

We report and verify a novel hue discrimination instrument. We also investigate its efficiency to determine hue discrimination in persons with normal color vision. Experimental and clinical investigation. The instrument setup comprises an optical unit and examination unit. The optical unit is composed of the same 2 spectrometers and their controllers, which enables the independent emission of different spectral lights. Two independent bundle fibers connect the optical unit and the examination unit. Two different wavelength lights are illuminated on the bipartite upper and lower circular objectives with a visual angle of 2 degrees in the examination unit. The examinee recognizes the difference in the spectral lights between the bipartite targets. Persons with normal color vision are examined and the findings are confirmed using the Ishihara Test for Colour Deficiency. The instrument could generate spectral light from 450 to 650 nm within 2-nm accuracy. The spectral light showed a different light intensity according to the spectral centroid, ranging from 450 to 650nm, but the difference could be adjusted and was negligible in terms of determination of hue discrimination using the power meter. Three width slits, 0.2mm, 0.5mm, and 1.0mm, to homogenize the light path were investigated. The half-width wavelength was accurate on each spectral centroid; however, the 0.5mm slit was suitable to generate an efficient light path. The hue discrimination differed among the study participants. In general, at short and long wavelength lights, the hue discrimination range was large: about 15nm at 450nm and about 10nm at 650nm. Between 470 and 620 nm, the hue discrimination showed good sensitivity and specificity between 8 and 2nm depending on the targeting wavelength lights. Intraindividual variation was small, ranging from 3 to 1nm, thus indicating good repeatability. The time to examine the hue discrimination was about 20min. This newly invented instrument using two independent spectrometer units enabled the determination of hue discrimination. The instrument's sensitivity and specificity including its repeatability were confirmed and indicated that the instrument could be a clinically applicable method.

Blue Light—Ocular and Systemic Damaging Effects: A Narrative Review

Light is a fundamental aspect of our lives, being involved in the regulation of numerous processes in our body. While blue light has always existed in nature, with the ever-growing number of electronic devices that make use of short wavelength (blue) light, the human retina has seen increased exposure to it. Because it is at the high-energy end of the visible spectrum, many authors have investigated the theoretical harmful effects that it poses to the human retina and, more recently, the human body, given the discovery and characterization of the intrinsically photosensitive retinal ganglion cells. Many approaches have been explored, with the focus shifting throughout the years from examining classic ophthalmological parameters, such as visual acuity, and contrast sensitivity to more complex ones seen on electrophysiological assays and optical coherence tomographies. The current study aims to gather the most recent relevant data, reveal encountered pitfalls, and suggest future directions for studies regarding local and/or systemic effects of blue light retinal exposures.

Wavelength-Dependent Effects of Photobiomodulation for Wound Care in Diabetic Wounds.

Photobiomodulation, showing positive effects on wound healing processes, has been performed mainly with lasers in the red/infrared spectrum. Light of shorter wavelengths can significantly influence biological systems. This study aimed to evaluate and compare the therapeutic effects of pulsed LED light of different wavelengths on wound healing in a diabetic (db/db) mouse excision wound model. LED therapy by Repuls was applied at either 470 nm (blue), 540 nm (green) or 635 nm (red), at 40 mW/cm2 each. Wound size and wound perfusion were assessed and correlated to wound temperature and light absorption in the tissue. Red and trend-wise green light positively stimulated wound healing, while blue light was ineffective. Light absorption was wavelength-dependent and was associated with significantly increased wound perfusion as measured by laser Doppler imaging. Shorter wavelengths ranging from green to blue significantly increased wound surface temperature, while red light, which penetrates deeper into tissue, led to a significant increase in core body temperature. In summary, wound treatment with pulsed red or green light resulted in improved wound healing in diabetic mice. Since impeded wound healing in diabetic patients poses an ever-increasing socio-economic problem, LED therapy may be an effective, easily applied and cost-efficient supportive treatment for diabetic wound therapy.

Tuning of Ultra-Thin Gold Films by Photoreduction.

Ultrathin metal films (UTMFs) are used in a wide range of applications, from transparent electrodes to infrared mirrors and metasurfaces. Due to their small thickness (<5 nm), the electrical and optical properties of UTMFs can be changed by external stimuli, for example, by applying an electric field through an ion gel. It is also known that oxidized thin films and nanostructures of Au can be reduced by irradiating with short-wavelength light. Here we show that the resistance, reflectance, and resonant optical response of Au UTMFs is changed significantly by ultraviolet light. More specifically, photoreduction and oxidation processes can be sequentially applied for continuous tuning, with observed modulation ranges for sheet resistance (Rs) and reflectance of more than 40% and 30%, respectively. The proposed method has the potential for achieving reconfigurable UTMF structures and trimming their response to specific working points, e.g., a predetermined resonance wavelength and amplitude. This is also important for large scale deployment of such surfaces as one can compensate material nonuniformity, morphological, and structural dimension errors occurring during fabrication.

A light-exploiting insectivorous bat shows no melatonin disruption under lights with different spectra.

Natural light-dark cycles synchronize an animal's internal clock with environmental conditions. The introduction of artificial light into the night-time environment masks natural light cues and has the potential to disrupt this well-established biological rhythm. Nocturnal animal species, such as bats, are adapted to low light conditions and are therefore among the most vulnerable to the impacts of artificial light at night (ALAN). The behaviour and activity of insectivorous bats is disrupted by short-wavelength artificial light at night, while long-wavelength light is less disruptive. However, the physiological consequences of this lighting have not been investigated. Here, we examine the effect of LEDs with different spectra on urinary melatonin in an insectivorous bat. We collected voluntarily voided urine samples from Gould's wattled bats (Chalinolobus gouldii) and measured melatonin-sulfate under ambient night-time conditions (baseline) and under red (λP 630 nm), amber (λP 601 nm), filtered warm white (λP 586 nm) and cool white (λP 457 nm) LEDs. We found no effect of light treatment on melatonin-sulfate irrespective of spectra. Our findings suggest that short-term exposure to LEDs at night do not disrupt circadian physiology in the light-exploiting Gould's wattled bat.