Connected autonomous vehicles must accurately detect, and adhere, to traffic light signals to ensure safe and efficient traffic flow. Misinterpretation of traffic lights can result in potential safety issues for drivers and pedestrians. Recent work demonstrated attacks that projected structured light patterns onto vehicle cameras, causing traffic signs and traffic light color misinterpretation. In this work, we characterize a novel vulnerability of traffic light physical structures that can be exploited by attackers to deceive recognition systems. When visible and invisible laser light is projected onto traffic lights, it is scattered by its internal reflectors. To a vehicle’s camera, the reflected light appears the same as a genuine light source, resulting in dangerous red and green traffic light status misclassifications. We evaluate our attack against three state-of-the-art traffic light recognition models and show successful misclassification up to 25 m from the target traffic light. Furthermore, the attack succeeds both in daytime and nighttime conditions both in static and moving vehicle scenarios up to 10 km/h speed. To mitigate this threat, we propose a detection system based on light texture patterns that achieve 100% TPR and 1.8% FPR in our real-world scenarios.

Existing spectral separation methods often suffer from high costs and poor portability. We propose an RGB three-channel partitioned multi-focus metalens based on the geometric phase principle. The aperture is divided into three non-overlapping lateral zones integrating heterogeneous nanopillars with high spectral selectivity. These structures respond independently to right-handed circularly polarized light at 405, 513, and 633nm, enabling precise phase modulation within each sub-aperture. Simulations demonstrate that the metalens focuses red, green, and blue light onto discrete lateral positions on a strictly co-planar focal plane, effectively circumventing the focal plane tilt inherent in traditional off-axis dispersion schemes. The achieved focusing efficiencies are 56.63%, 68.65%, and 76.55%, with focal spot sizes approaching the diffraction limit. Featuring an ultrathin profile and high integration, the proposed device provides a robust planar-optic solution for miniature color imaging and integrated multi-spectral systems.

This study evaluated the effects of different light-emitting diode (LED) spectral qualities on the early growth of kale at the baby-leaf harvest stage in a plant factory with artificial lighting (PFAL) by integrating morphological traits, biomass accumulation, plant quality indices, vegetation indices, and chlorophyll a fluorescence. Two kale (Brassica oleracea L.) cultivars, ‘Jellujon’ and ‘Manchoo Collard’, were grown for four weeks under monochromatic red, green, and blue LEDs, a purple composite LED with far-red wavelengths, and three white LEDs with different correlated color temperatures (3000, 4100, and 6500 K). Blue LED increased shoot height by approximately 14–28%, depending on cultivar and comparison among the white LED treatments, but this elongation did not translate into superior biomass production. In contrast, white LEDs, particularly at 3000–4100 K, increased leaf area to 24.2–24.9 cm2 and SPAD units to 47.3–50.2, whereas blue or green LEDs generally resulted in smaller leaves and lower SPAD units. Shoot dry weight under 3000–4100 K white LEDs reached 0.25–0.26 g in ‘Jellujon’ and 0.26–0.29 g in ‘Manchoo Collard’, approximately twofold higher than under blue or green LEDs. Compactness, Dickson quality index, root investment ratio, and leaf efficiency index were also more favorable under white LEDs, indicating improved plant sturdiness and structural stability. Green LED light was associated with lower maximum photochemical efficiency (ΦPo) and greater energy dissipation (ΦDo and DIo/RC), whereas photochemical reflectance index and PIABS tended to be more favorable under selected white LED treatments, although these responses were partly cultivar- and treatment-dependent. Taken together, among the LED spectral quality treatments tested, 3000–4100 K white LEDs provided the most consistently favorable conditions for producing structurally robust, high-quality kale at the early growth stage in PFAL systems. The purple LED showed partial advantages in leaf development and selected physiological responses, but these effects were less consistent across cultivars and indices.

Background: Circular economy encourages environment protection and social prosperity while giving the green light to economic growth with sustainable development in a country. The apparel industry both globally and Sri Lanka faces considerable environmental challenges and it is recognized as a major consumer of water. Aim: This study seeks to identify the challenges and opportunities of adopting circular economy practices to enhance resource efficiency in the apparel manufacturing industry of Sri Lanka, under social, environmental, and economic aspects. Methods: Within the apparel industry, circular design, product life extension, textile recycling, and resource efficiency were identified as key circular economy practices. Qualitative research approach was adopted to identify the social, environmental, and economic aspects of circular economy adoption. Target population consisted of key stakeholders in Sri Lanka’s apparel manufacturing sector, including lean managers, sustainability officers, supply chain professionals, and employees involved in circular economy-related practices. Given the qualitative nature of this study, a purposive sampling strategy was adopted to select 4 respondents. A semi-structured interview used as the primary method of data collection and content analysis used to identify key factors through participants’ responses. Results: The results revealed that circular economy is understood among Sri Lankan apparel manufacturers as a strategic shift from linear “take-make-dispose” model to a closed-loop system that keeps materials in use for as long as possible. Despite facing notable challenges such as high initial costs, limited infrastructure, and low awareness, companies are making steady progress through innovation, collaboration, and commitment to sustainability goals. The social findings revealed the need for awareness and training to drive behavioral change, while environmental results confirmed significant achievements in waste reduction, water reuse, and carbon footprint minimization. Economically, although initial investments are high, long-term cost savings, market differentiation, and stronger buyer relationships make circular adoption a viable and strategic direction for the industry. Implications: Apparel manufacturers in Sri Lanka need to implement circular economy principles as port of their core business strategy rather than as isolated sustainability projects. Capacity building in employees and suppliers through continuous awareness and training program; collaborating across the supply chain actors, leveraging circularity for brand differentiation; developing the supportive policy frameworks; expanding recycling and waste management infrastructure and establishing regulatory and certification system would encourage to take part in circular transformation. Further Study: This study focused on the manufacturing perspective; future research could explore consumer behavior, buyer expectations, and government policy roles in enabling circular transformation.

Amino acids with β,β-carbocyclic sidechains are valuable replacements for endogenous Val, Leu, and Ile, with therapeutic benefits. When placed into ordinary peptides, these annulated variants improve metabolic stability, cell permeability, and receptor affinity and selectivity. Yet, their appearance in modern peptide drugs is often limited to β,β-cyclopentyl- and β,β-cyclohexyl-rings, one reason being the limited availability of resin- and solution-compatible β,β-carbocyclic amino acids for direct coupling. More 'exotic' rings, i.e., those with different sizes, chemical compositions, and geometric preferences, could be superior, but finding and assessing their benefits calls for more general ways to incorporate and test them. Herein, we pioneer a modular route to convert a single unsaturated residue, known as β-sulfonyldehydroamino acid (ΔSulf), in a peptide into many unique β,β-carbocycles-cyclic, polycyclic, and heteroatom-containing-in two telescoped steps. First, an unprecedented photocatalyst, Pyronin Y, in an original combination with an organodiiodide, cobalt porphyrin catalyst, sacrificial amine, and green LEDs converts ΔSulf into a Δ-amino acid with a pendant iodide. Adding Zn/Cu couple then triggers an intramolecular and stereoselective Giese cyclization. We detail the mechanism of our procedure, highlighting the interplay between aqueous metallaphotoredox catalysis, halogen-atom abstraction, and ligand-controlled cyclization using spectroscopy, cyclic voltammetry, intermediate-trapping, and radical-clock experiments.

Alkene relocation to create structural diversity from abundant chemotypes is prevalent in biology but conspicuously underdeveloped in synthetic chemistry. Interconverting constitutional isomers that are partitioned by small energy differences requires intractable thermo- and regiochemical challenges to be overcome, and this continues to limit ground-state positional isomerization. In contrast, light-based activation allows excited-state reactivity to be leveraged to tackle intractable selectivity issues and mimic biochemical isomerization. Emulating steroid Δ5-isomerase, a mild photocatalytic deconjugation of cyclohexenone motifs is reported in which a traceless C(sp3)-Br handle is leveraged to bias regioselective generation of a key photodienol. Irradiation with green light (520 nm) in the presence of an organophotoredox catalyst (eosin Y), a base (NaOAc), and a sacrificial reductant (HEH2) enables the endo-selective debrominative deconjugation of a diverse range of brominated cyclic enones: this expedites access to β-isophorone (an industrial precursor for vitamin and carotenoid synthesis) as well as 3-oxo-Δ5-steroids that are common in hormones and oncology drugs (e.g., Zytiga).

Light exposure is a primary zeitgeber for the human circadian system and plays a key role in shaping sleep-wake patterns during adolescence, a period marked by biological sensitivity and social constraints. How the temporal organization and spectral composition of daily light exposure differ between weekdays and weekends remains poorly understood. Eighteen adolescents (15-17 years) were monitored for seven days using wrist actigraphy with integrated light sensors. Sleep parameters, nonparametric circadian rhythm indices, and time-resolved profiles of ambient and spectral (blue, green, and red) light exposure were analyzed. Repeated-measures ANOVA tested the effects of time of day and day type. Total sleep time and time in bed were longer on weekdays than on weekends (p < 0.05), while sleep latency and WASO did not differ. Circadian indices indicated preserved rhythmic organization. Light exposure showed a robust diurnal profile, with higher spectral irradiance on weekends (p < 0.001), especially in the morning and early afternoon. Significant time × day-type interactions were observed across all spectral bands (p < 0.001), indicating systematic reshaping of daily light profiles. Adolescents exhibit weekday-weekend differences in the temporal and spectral organization of light exposure, affecting the amplitude and shape of overall daily profiles.

Effects of Combined UV-A/B and Green Light Exposure on Growth Performance, Photosynthesis, and Antioxidant Defense in Grafted Watermelon Seedlings

To accurately quantify the intrinsic absorption efficiency of bamboo leaves to the solar spectrum, we measured the reflectance and transmittance of leaves from 55 bamboo species cultivated at the same site, and developed a mathematical model to calculate the annual cumulative photon absorption of photosynthetically active radiation (PAR) per leaf. The results showed the following: (1) Bamboo leaf optical properties exhibited high instrumental and spatial measurement consistency, with transmittance not significantly fluctuating with changes in incident light intensity or quality. (2) Bamboo leaves exhibited significant spectral selective absorption characteristics, with stronger absorption of blue and red light and weaker absorption of green light; Phyllostachys vivax had the highest mean absorptance per unit area, while Chimonobambusa tumidinoda had the lowest. (3) The annual photon absorption per unit leaf area ranged from 1.83 × 105 to 9.86 × 105 μmol, with Phyllostachys iridescens being the lowest and Chimonobambusa marmorea the highest. The annual photon absorption per single leaf ranged from 1.84 × 106 to 5.13 × 107 μmol, with Indocalamus decorus achieving the highest total absorption due to its largest leaf area (114.9 cm2), while Bambusa multiplex var. riviereorum was the lowest. (4) All tested bamboo species showed consistent seasonal dynamics in photon absorption, with the highest in summer and lowest in winter. Although unit-area absorptance reflects the intrinsic light interception efficiency, leaf morphology has a substantial influence (explaining 99.56% of the variance) in determining total light acquisition per leaf.

Developing robust materials that exhibit full-color, switchable, circularly polarized luminescence (CPL) remains a significant challenge. Herein, we report a facile, one-pot encapsulation of achiral dyes within chiral metal-organic frameworks (MOFs) for tunable CPL emission. This approach leverages the chiral microenvironment of MOFs to transfer chirality to the dye molecules, as evidenced by distinct mirror-image circular dichroism (CD) signals. Notably, the confinement effect not only imparts CPL activity to the guest molecules but also enhances their emission intensity via host-guest energy transfer. By controlling the encapsulation of dyes that emit blue (CBS), green (C6), and red (RB) light, we successfully achieved tunable CPL emission across the entire visible spectrum. Furthermore, optimizing the mass ratio of three trichromatic dyes yielded white-light CPL emission with a CIE 1931 coordinate of (0.30, 0.32) and a dissymmetry factor (glum) of |2 × 10-3|.

Hydrangea ( Hydrangea macrophylla ) is a widely grown ornamental nursery crop, but its vigorous shoot growth often necessitates pruning or repeated applications of plant growth regulators (PGRs) to achieve saleable size, which increases production costs and labor inputs. Passive strategies to manage shoot growth are desirable alternatives to pruning and PGR use. Shade materials are routinely applied in hydrangea production to protect foliage from excessive solar radiation, typically using 30% to 50% black netting. Beyond reducing light intensity, shade nets also can modify light quality by altering the relative proportions of blue (400–499 nm), green (500–599 nm), and red (600–699 nm) light, which can influence plant morphology. Blue shade nets, which primarily absorb green and red light, are often marketed as tools to produce more compact plants and could provide a passive alternative to pruning or PGR applications. This study evaluated the effects of shade color (black, blue, red, and gray) and shade percentage (40% to 75% blue shade) on the growth and morphology of hydrangea ‘Twist and Shout’ in a commercial nursery and research greenhouse experiments. In the nursery experiment, hoop houses were covered with 30% black, blue, or red, or 45% gray shade netting. In the greenhouse experiment, chambers were covered with 40%, 50%, or 75% blue shade or 50% black shade. Blue shade of any percentage did not suppress shoot growth in either experiment. Increasing shade percentage in general increased plant growth index, a proxy for aboveground shoot size, but decreased leaf length and chlorophyll concentration. Shade color did not eliminate the need for pruning or PGR applications of hydrangea to control shoot growth.

Phototribology of copper surfaces

BackgroundPhotophobia is experienced by most individuals with migraine, and it is frequently the most bothersome symptom other than headache. Light is not perceived uniformly; spectral composition and intensity influence discomfort and can exacerbate symptoms. While monochromatic green light shows therapeutic potential, it appears visually unnatural and is impractical for daily use. This study aimed to determine whether spectrally tailored white light, more visually acceptable in everyday environments, reduces light sensitivity among those with migraine.MethodsTwenty adults (18-44 years) with episodic migraine completed two research sessions: one during an acute migraine attack and one between migraine attacks. Participants were exposed to four spectrally distinct white light conditions (red-, green-, cyan-, and blue-enriched) in a randomized order delivered at ten intensity levels (50-590 lux). After each exposure, visual discomfort was rated on a 0-10 scale. Pupil size was measured using a pupillometer. Repeated-measures ANOVAs examined the effects of light spectrum, intensity, and migraine state on visual discomfort and pupil response.ResultsMigraine attack status significantly increased visual discomfort (F(1,19) = 25.84, p < .001, η2 = .576). White light spectrum (F(3,57) = 12.47, p < .001, η2 = .396) and light intensity (F(9171) = 124.30, p < .001, η2 = .867) were associated with intensity of visual discomfort. Post-hoc analyses indicated that visual discomfort increased with increasing light intensity, especially at higher light intensities. Among all tested spectra, green-enriched white light resulted in the least visual discomfort; blue-, red-, and cyan-enriched white light produced significantly higher discomfort (all p < .001). Pupil size varied by spectrum (F(3,57) = 14.13, p < .001, η2 = .426), with green-enriched white light producing the largest pupil size.ConclusionSpectral composition, light intensity, and migraine state jointly influence both subjective and physiological responses to light. Across lighting spectra, lower light intensity was consistently associated with reduced visual discomfort, indicating greater visual comfort at lower intensities. These results identify green-enriched white light at lower intensities as a visually acceptable, migraine-conscious lighting option with potential for real-world application.

Chiral epoxides are valuable intermediates widely used in pharmaceutical synthesis and functional materials. In this work, herein, we designed and developed a bifunctional chiral catalyst by grafting a photosensitizing unit onto chiral iron complexes of (R,R)−3,4‐diaminopyrrolidine‐derived N4 ligands. Employing molecular oxygen or air as a green oxidant and visible light as the driving force, this catalytic system successfully achieved asymmetric epoxidation of chalcones, furnishing the desired epoxides in high yields with excellent enantiopurity.

[2 + 2] Photocycloadditions are one of the most important classes of photochemical reactions and are often employed in soft matter materials science. However, the wavelength resolved investigation of [2 + 2] based photopolymerizations has not been examined. Herein, we initially introduce a photoreactive alkene (nitrovinyl pyrene), which displays strong absorption in the visible light spectrum, extending to the green light (λ > 500 nm) region. Chromophore conversion and cycloaddition yield were quantified through a photochemical action plot using 1H NMR spectroscopy. A local maximum in the wavelength dependent quantum yield was observed close to 520 nm, revealing a strong mismatch between absorptivity and reactivity, i.e. higher values are observed at excitation wavelengths that are red-shifted relative to the absorption maximum. To ultimately map the wavelength dependence of a photopolymerization based on the introduced chromophore, we subsequently establish a size-exclusion chromatography (SEC)-based method to map the nitrovinyl pyrene species depletion as a function of wavelength, introducing an SEC-based photochemical action plot methodology. We next modify our chromophore with a second nitrovinyl group, making it a photoreactive bifunctional monomer, leading to a further redshift in its absorbance maximum and an increased quantum yield at 550 nm. We finally apply our SEC-based photochemical action plot methodology to map the wavelength-dependent [2 + 2] photopolymerization of the dinitrovinyl chromophore and demonstrate a significant effect of monochromatic wavelength on the product distribution of the individual chains, highlighting how changes in the electronic properties─particularly the size of the conjugated system─of multifunctional chromophore monomers can be exploited to control photopolymerizations via irradiation wavelength.

We develop CsxFA1-xPbI3 perovskite photodetectors with varying Cs content in the x = 0.05-0.25 range to identify the most stable cubic-lattice perovskite composition for visible-light photodetection. The perovskite layers were deposited by the spin-coating technique on a nickel oxide p-type contact and then were covered with C60/Ag electron contact to obtain a vertical pin diode structure. X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements show that x = 0.1-0.2 provides the most stable lattice and pinhole-free perovskite layers. The photocurrents are linear in an extremely wide 1 nW-10 mW excitation power range, providing photoresponsivity of 0.28 A/W at 532 nm (green light), similar to that of Si photodiodes. The testing of the photodetectors using picosecond pulses provided their rise times and fall times. The x = 0.2 composition provided the shortest rise time values of 27.5 ns, leading to a detector modulation bandwidth of 12.7 MHz. This indicates that this perovskite composition is suitable for replacing silicon photodetectors in cost-efficient light detection systems for imaging and light communication applications such as Li-Fi.

Light spectral composition plays a central role in regulating plant growth, morphology, nutrient uptake, and pigment biosynthesis, particularly in controlled-environment agriculture. This study investigated the effects of targeted LED spectral modulation, focusing on green light deprivation and different red-to-blue (R:B) ratios at constant photon flux density, on morphological traits, mineral composition, and photosynthetic pigments in Salvia officinalis L. and Cannabis sativa L. grown under controlled conditions. Plants were cultivated under three LED treatments providing equal light intensity but differing in spectral composition. Morphological parameters, mineral nutrients, inorganic anions, and photosynthetic pigments were assessed at harvest. Total biomass production was not significantly affected by the light treatments in either species; however, clear species-specific responses were observed. In S. officinalis, higher R:B ratios promoted stem elongation without affecting leaf number or fresh weight, whereas in C. sativa, the higher R:B ratio significantly increased leaf number. Green light deprivation and red-blue enrichment generally enhanced mineral accumulation and nitrogen content, although the magnitude and direction of these effects varied between species. Photosynthetic pigment responses were more pronounced in hemp, with increased chlorophylls and carotenoids under green light deprivation, while salvia showed a selective increase in carotenoids under higher R:B ratios. Overall, these findings emphasize the importance of species-specific LED spectral optimization to improve physiological performance and nutritional quality in indoor cultivation of medicinal plants.

ABSTRACT Throughout their evolution, insect species have adapted in different ways to light stimuli, exhibiting phototactic behaviours that vary according to the wavelength, intensity and quality of light. In this study, the phototactic response of Conotrachelus psidii Marshall, 1922 (Coleoptera: Curculionidae) to different light spectra was evaluated. To perform the bioassays, adults of C. psidii were collected from guava orchards and placed in a phototactic arena consisting of three sections: two lateral sections containing light sources and a central section designated for insect release. Six LED light sources were used: red (612 nm), yellow (594 nm), green (520 nm), blue (455 nm), white (449 and 535 nm) and ultraviolet (365 and 405 nm). A total of 360 adults were evaluated in three experimental assays: (1) unsexed insects exposed to one light at a time; (2) sex‐separated insects exposed to one light at a time; and (3) unsexed insects exposed to two lights simultaneously. The effect of light exposure on the duration of thanatosis behaviour was also evaluated, justified as an antipredator strategy that may influence the dispersal and survival of C. psidii adults under field conditions. The results indicated that red light elicited a significantly higher positive phototactic response (approximately 65% of males moved toward the red light) in males, whereas females did not show significant attraction to any spectrum. Both sexes showed significant aversion to ultraviolet (UV) and white light, with less than 20% of adults entering these sections. In the choice tests, red light attracted significantly more adults than yellow, green and ultraviolet lights. Exposure to different light spectra also affected the duration of thanatosis, with males exhibiting longer immobility under blue light and females under dark and blue‐green conditions, suggesting sex‐specific behavioural strategies. The results suggest that red light can be cautiously considered for developing selective light traps for monitoring C. psidii in Integrated Pest Management (IPM) programmes, contributing to early detection and improved pest management in guava orchards.

To date, transition metal dichalcogenides (TMDCs) are mostly explored as 2D semiconducting materials due to their distinctive properties as compared to their bulk counterparts while similar research focus on post-transition metal dichalcogenides (PTMDCs) is still in infancy. Here, we demonstrate an interesting contrast between photocarrier dynamics in quasi-2D van der Waals TlGaS2, revealed through a comparative study of single-crystal and exfoliated microflake. The single crystal exhibits pronounced temperature-sensitive spectral features indicative of strong carrier-phonon coupling and delivers a maximum responsivity of 5 mA/W under 490 nm illumination. In contrast, the microflake shows faster, weakly temperature-dependent carrier relaxation and narrowband blue-UV selectivity. Remarkably, the microflake demonstrates an enhanced responsivity of 32.1 mA/W, with a negligible response to green and red light, revealing TlGaS2 single crystals as visible photodetectors with optically tunable switching, while the microflake as a low-power, blue-UV selective, temperature-robust optical-digital conversion system. Most importantly, this work provides fundamental insight into temperature-dependent carrier transport and dimensionality-driven photocarrier dynamics in quasi-2D PTMDCs.

Ferroptosis, a recently described form of regulated, nonapoptotic cell death mechanism, presents significant potential for cancer treatment, particularly when combined with photodynamic therapy (PDT). In this study, we report the synthesis and biological evaluation of a series of Ir-COUBPY complexes as novel photosensitizers (PSs) for effective cancer phototherapy. These complexes exhibit high stability under both dark and light conditions and are capable of photogenerating Type I and Type II reactive oxygen species (ROS), as well as photo-oxidizing NADH. Electron paramagnetic resonance (EPR) spectroscopy provided direct evidence of light-induced superoxide and singlet oxygen generation, confirming dual ROS pathways. Moreover, the Ir-COUBPY complexes preferentially accumulated in the mitochondria of cancer cells, leading to the photogeneration of hydroxyl radicals and hydrogen peroxide. Photocytotoxicity studies on HeLa and A375 cancer cells underscored the role of the COUBPY ligand in enhancing PDT efficiency upon irradiation with both green and red light. Among the Ir-COUBPY complexes, the most effective PS, Ir4a, was encapsulated in polyurethane-polyurea hybrid nanocapsules (NC-Ir4a), resulting in a significant increase in phototoxic index values (e.g., from 64 to 179.6 in A375 cells). Mechanistic studies confirmed ferroptosis as the primary cell death pathway induced by Ir4a, supported by light-dependent lipid peroxidation, glutathione oxidation and depletion, intracellular ATP photodepletion, and the viability-restoring effect of Fer-1. These effects were more pronounced upon nanoencapsulation. Photobiological studies with 3D tumor spheroids of A375 cells further confirmed higher cellular uptake of NC-Ir4a, contributing to improved phototoxic efficiency. Overall, these findings highlight the potential of coumarin-based COUBPY ligands in the design of new Ir-(III)-based PSs that can be activated with light within the phototherapeutic window, operating through nonconventional cell death mechanisms such as ferroptosis.