Variation Of Light Intensity Research Articles

Light Modulation of Photosynthate Accumulation in Microgreens Grown in a Controlled Environment During Storage

Light intensity and spectral composition are the main parameters that may be modulated to further affect plant nutritional value and shelf life. The current study aimed to assess how variations in spectral composition and light intensity affect sugar accumulation during the storage of two popular microgreens cultivated in a greenhouse under controlled conditions. Thus, in this study, amaranth (Amaranthus tricolor) and mustard (Brassica juncea) microgreens were grown in a greenhouse at 17/20 ± 3 °C and a 16 h photoperiod was maintained. (I) Four LED light intensities were set: 100, 150, 200, and 250 µmol m−2 s−1 while using 4000 K white LED lighting. (II) Maintaining 250 µmol m−2 s−1 the effect of spectrac composition: B75.6%:R24.2%:W0.02%/R88.9%:B11.1%/and R77.6%:W9.9%:B3.5% was evaluated. After 10 days from germination, microgreens were harvested and stored in the dark or under white LED light at +4 °C. Samples were collected on D0, D1, D3, and D5 days of postharvest storage. The results revealed that a wide spectrum of 250 µmol m⁻² s⁻¹ PPFD and R88,9%: B11,1% growing conditions produced the highest sugar content, achieving a balance between increased sugar accumulation and reduced deterioration during storage, ultimately extending shelf life.

Rotation of polarization plane of a laser beam by fluid vorticity

The polarization plane of a beam of light experiences angular drag when it traverses a medium rotating about an axis parallel to the direction of the beam. Here, fluid vorticity in a horizontal Rijke tube is used to cause rotation in the polarization plane of a continuous laser beam. The vorticity distribution and acoustic pressure history in the tube have been predicted numerically. The thermo-acoustic phenomenon in the tube has been found to generate the vorticity. A suitable optical arrangement has been used to capture the light intensity variation due to the rotation of the plane of polarization of the beam, and up to 4° of rotation has been observed.

Differences in carbon and nitrogen metabolism of soft japonica rice in southern China during grain filling stage under different light and nitrogen fertilizer conditions and their relationship with rice eating quality

Light and nitrogen are crucial environmental factors that significantly impact rice growth and quality formation. Currently, there is a lack of systematic research on how light and nitrogen affect carbon and nitrogen metabolism during grain filling, subsequently affecting the eating quality of rice. To address this gap, field experiments were conducted under varying light intensities and nitrogen fertilizer levels to investigate the changes in carbon and nitrogen metabolism during grain filling, the eating quality of rice at maturity, and the relationship between them. The findings revealed that, 50% light intensity suppressed carbon metabolism while stimulating nitrogen metabolism, resulting in a reduction in the C/N ratio, decreased starch content by 4.30% to 5.59%, and elevated protein content by 21.31% to 29.70%, thereby leading to decreased rice eating quality by 10.06% to 11.42%. Conversely, the application of panicle fertilizer boosted nitrogen metabolism while hindering carbon metabolism, leading to a decrease in the C/N ratio, increased protein content by 21.31% to 29.70%, and reduced starch content by1.60% to 2.93%, thereby leading to decreased rice eating quality by 4.13% to 6.71%. Correlation analysis revealed a significant positive correlation between the C/N ratio and carbon metabolism-related enzyme activities and products, along with a significant negative correlation with nitrogen metabolism-related enzyme activities and products, suggesting that the C/N ratio can serve as an indicator of carbon and nitrogen metabolism levels. Further analysis revealed a significant positive relationship between the C/N ratio and taste value, indicating that higher levels of carbon metabolism promote the development of good rice eating quality, while nitrogen metabolism exerts an opposing influence. In summary, notable variances in carbon and nitrogen metabolism were observed within the same japonica rice cultivar under diverse light and nitrogen fertilizer conditions. These metabolic differences impact the synthesis of starch and protein in the endosperm, ultimately influencing rice quality. Our study contributes to a more profound comprehension of the regulation of carbon and nitrogen metabolism in rice by light and nitrogen fertilizer, as well as their role in determining eating quality.

SOLAR TRACKING SYSTEM USING ARDUINO

This research focuses on the development of a solar tracking system using an Arduino microcontroller to optimize the energy efficiency of photovoltaic solar panels. The conventional fixed solar panel setup often leads to suboptimal energy capture as the panel’s orientation remains static, resulting in reduced efficiency due to the sun’s changing position throughout the day. To address this, the proposed system employs a dual-axis solar tracker mechanism that automatically adjusts the solar panel's orientation to align with the sun's trajectory, maximizing solar energy absorption. The system utilizes Light Dependent Resistors (LDRs) placed on either side of the solar panel to detect variations in light intensity. Based on the sensor readings, the Arduino microcontroller processes the information and drives servo motors to move the panel in real time, ensuring it faces the sun. The servo motors allow for precise angular adjustments, enabling both horizontal and vertical movement to track the sun across the sky. The Arduino-based control system is simple, cost-effective, and easily programmable, offering an accessible solution for enhancing solar power efficiency. A comparative analysis between the solar tracker and a fixed-panel setup shows that the tracking system significantly improves energy capture by maintaining optimal sunlight exposure throughout the day. The paper also discusses the challenges involved in system calibration, the reliability of sensor data, and the mechanical aspects of the tracking mechanism. Results demonstrate that the solar tracking system can increase energy output by up to 30% compared to static panels. The findings indicate that the proposed low-cost solar tracking system holds significant potential for large-scale solar applications, contributing to the increased adoption of renewable energy solutions and enhancing the overall performance of solar power systems. Experimental evaluations were conducted to compare the energy output of the solar tracker against a fixed-panel setup. The results indicate a significant improvement in energy generation with the tracking system. The solar tracker’s ability to follow the sun maximizes light absorption and increases the efficiency of the photovoltaic panel by up to 30% compared to a fixed panel. The system demonstrates notable advantages, including higher energy yields, better adaptability to changing weather conditions, and the ability to capture sunlight at different times of the day. Key Words: Solar Tracker, Light Detecting Resistor (LDR), Arduino, Servo Motor

High‐Performance UV–Vis–NIR Photodetectors Based on PEDOT Obtained by Plasma‐Enhanced Chemical Vapor Deposition

This study presents the fabrication of organic UV–vis–NIR photodetectors based on poly(3,4‐ethylenedioxythiophene) (PEDOT) thin films synthesized via a plasma‐enhanced chemical vapor deposition at 10, 20, and 30 W plasma power. The effects of plasma power on polymerization, as well as optical, structural, morphological, and optoelectronic properties, are analyzed using UV–vis, Fourier transform infrared spectroscopy, scanning electron microscope, and scanning electron microscopy–energy‐dispersive X‐ray. The films, exhibiting a bandgap of 3.52–3.59 eV, are uniformly coated on Si surfaces. Photodiode and photodetector performance is evaluated through current–voltage and current–transient measurements under varying light intensities and wavelengths. PEDOT films synthesized at 10 W exhibit superior photodetector performance, with maximum responsivity and detectivity of 0.0975 A W−1 and 1.65 × 1010 cm Hz0.5 W−1 at 900 nm, and a noise‐equivalent power of 5.38 × 10−12 W Hz−1/2. Maximum external quantum efficiency is recorded as 23.975% at 450 nm. These results emphasize the suitability of low‐power PEDOT films for optoelectronic applications due to their superior morphology and optoelectronic characteristics.

Luminescent Lanthanide Infinite Coordination Polymers for Ratiometric Sensing Applications.

Ratiometric lanthanide coordination polymers (Ln-CPs) are advanced materials that combine the unique optical properties of lanthanide ions (e.g., Eu3+, Tb3+, Ce3+) with the structural flexibility and tunability of coordination polymers. These materials are widely used in biological and chemical sensing, environmental monitoring, and medical diagnostics due to their narrow-band emission, long fluorescence lifetimes, and excellent resistance to photobleaching. This review focuses on the composition, sensing mechanisms, and applications of ratiometric Ln-CPs. The ratiometric fluorescence mechanism relies on two distinct emission bands, which provides a self-calibrating, reliable, and precise method for detection. The relative intensity ratio between these bands varies with the concentration of the target analyte, enabling real-time monitoring and minimizing environmental interference. This ratiometric approach is particularly suitable for detecting trace analytes and for use in complex environments where factors like background noise, temperature fluctuations, and light intensity variations may affect the results. Finally, we outline future research directions for improving the design and synthesis of ratiometric Ln-CPs, such as incorporating long-lifetime reference luminescent molecules, exploring near-infrared emission systems, and developing up-conversion or two-photon luminescent materials. Progress in these areas could significantly broaden the scope of ratiometric Ln-CP applications, especially in biosensing, environmental monitoring, and other advanced fields.

Cycling Dof Factor 3 mediates light-dependent ascorbate biosynthesis by activating GDP-l-galactose phosphorylase in Rosa roxburghii fruit.

Light plays an important role in determining the l-ascorbate (AsA) pool size in plants, primarily through the transcriptional regulation of AsA metabolism-related genes. However, the specific mechanism of transcriptional induction responsible for light-dependent AsA biosynthesis remains unclear. In this study, we used a promoter sequence containing light-responsive motifs from GDP-L-galactose phosphorylase 2 (RrGGP2), a key gene involved in AsA overproduction in Rosa roxburghii fruits, to identify participating transcription factors. Among these factors, Cycling Dof Factor 3 (RrCDF3) was highly responsive to variations in light intensity, quality, and photoperiod, leading to alterations in RrGGP2 expression. Further yeast one-hybrid and dual-luciferase assays confirmed that RrCDF3 acts as a transcriptional activator of RrGGP2 by binding specifically to its promoter. Modulating the expression of RrCDF3 in fruits through transient overexpression and silencing resulted in significant changes in RrGGP2 expression and AsA synthesis. Additionally, the stable overexpression of RrCDF3 in R. roxburghii calli and Solanum lycopersicum plants resulted in a significant increase in AsA content. Notably, the well-known photo-signal transcription factor ELONGATED HYPOCOTYL5 (RrHY5) directly interacted with the RrCDF3 promoter, enhancing its transcription. These findings reveal a special mechanism involving the RrHY5-RrCDF3-RrGGP2 module that mediates light-induced AsA biosynthesis in R. roxburghii fruit.

Machine learning-based wavelength detection system

Abstract A portable wavelength detection system has potential applications in various fields, including chemistry, biology, physics, and environmental sciences. Conventional systems rely on optical components, such as filters or slits, to separate light wavelengths, leading to complex measurement structures and challenges in miniaturization. Additionally, signals generated by light are susceptible to environmental factors and electrical interference, making traditional programming methods insufficient for accurate signal correction. To overcome these limitations, this study proposes an artificial intelligence-based filter-free wavelength sensor system that identifies wavelengths using the absorption coefficient of silicon. The proposed system consists of an analog circuit that applies signal conversion and noise reduction techniques for photocurrent from the filter-free wavelength sensor, and a microcontroller embedded with machine learning algorithms to process signals and calculate wavelengths in real-time. The system can detect central wavelengths in the 400–700 nm range, even with variations in light intensity, and corrects signals using embedded machine learning data. The system demonstrated the ability to identify wavelengths with a 1.74% error rate, even when light intensities varied between 0.20, 0.25, and 0.30 mW cm−2. By leveraging the absorption coefficient of silicon and machine learning algorithms, a system has been developed that enables real-time wavelength detection regardless of changes in light intensity.

Living in Biological Darkness II: Impact of Winter Habitual Daytime Light on Night-Time Sleep.

Timing and architecture of sleep are co-driven by circadian rhythms modulated by their major Zeitgeber light and darkness. In a natural environment, one is exposed to 3.000 lx (cloudy winter sky) to 100.000 lx (bright sunny sky). The aim of the study was to assess (1) habitual daytime light exposure in urban winter and (2) impact of daytime urban light on objective night-time sleep. Eleven healthy participants (mean age ± SD: 25.4 ± 2.8 years; 6 male) wore eyeglass frames continuously recording daytime illuminance levels vertically to the eye by mounted sensors (range: 1-40.000 lx) during four consecutive days in winter 2008 in Berlin, Germany. In-lab polysomnography was performed over two nights in nine participants. Median light exposure over 4 days was the following: full day 7:00-19:00 h: 23 lx (12-37 lx); morning 7:00-11:00 h: 81 lx (19-201 lx); midday 11:00-15:00 h: 68 lx (19-164 lx); afternoon 15:00-19:00 h: 22 lx (6-58 lx), resulting in only 36 min > 500 lx per day. Timing of daytime light intensity was significantly associated with subsequent sleep: lower midday illuminance with shorter REM latency (Rho = 0.817; p = 0.049) and earlier REM polarity (less prevalence of REM at end-of-sleep; Rho = 0.817; p = 0.049). Humans, living in an urban environment, appear to be exposed to extremely low light levels, which we named as 'Living in Biological Darkness'. Most fascinating, physiology seems to adapt and responds to variation in light intensity on such low levels. Interestingly, the observed changes in sleep architecture with low light levels are reminiscent of those suspected to constitute biological markers of depression some 40-50 years ago.

Synthesis and Characterization of Photocurable Difunctional Monomers for Medical Applications.

Photocurable materials offer a rapid transition from a liquid to a solid state, and have recently received great interest in the medical field. However, while dental resins are very popular, only a few materials have been developed for soft tissue repair. This study aims to synthesize a difunctional methacrylate monomer using a dibutyltin dilaurate which is suitable for the photocuring of soft materials. These soft materials were compared with PhotoBioCure® (Szczecin, Poland) material with a similar molecular weight, of Mn ~7000 g/mol on average. Infrared spectroscopy was used to monitor the two-step synthesis catalyzed with dibutyltin dilaurate, while spectroscopic and chromatographic methods were used to determine the chemical structure and molecular weight of the monomers. Photopolymerization kinetics under varying light intensities were explored in a nitrogen atmosphere for representative difunctional monomers. The mechanical testing of the resulting elastomeric films confirmed tensile strength and modulus values consistent with soft tissue parameters in the range of 3-4 MPa. The 3D printability of the macromonomers was also assessed. Additionally, cytotoxicity assessments using cultured cells showed a high cell viability (97%) for all new materials. Overall, we demonstrate that difunctional methacrylate monomers converted to flexible solids during photopolymerization show great potential for biomedical applications.

Effect of Light Intensity on Ammonium Removal and Biomass Growth in Different Levels of Aquaculture Effluent Using Duckweed (Lemna perpusilla)

Cultivating duckweed in aquaculture effluent offers a viable approach to eliminating contaminants. The duckweed biomass obtained can be utilized for the generation of bioenergy. However, elevated levels of ammonium (NH4+) in aquaculture effluent, combined with variations in light intensity, can hinder biomass formation. The precise mechanisms underlying this inhibition remain incompletely elucidated. The study assessed the efficacy of duckweed (Lemna perpusilla) as a treatment agent for wastewater from catfish farms. The objective was to evaluate the growth response of duckweed and its efficacy in reducing ammonium levels. The research demonstrated that daily light intensity fluctuated using shade nets and that the ammonium concentration of aquaculture wastewater varied according to the age of the fish. The shade nets, which blocked 25% of the sunlight and had an average daily light intensity of 3433.34–15199.56 lux, demonstrated a slightly elevated NH4+ removal efficiency and duckweed productivity of 69.34% and 0.050 kg/m²/day, respectively. However, these values were not statistically significant when compared to conditions without shade nets, which had a removal efficiency of 63.97% and duckweed productivity of 0.042kg/m2/day (P<0.05). The implementation of shade structures that effectively decrease solar exposure by 25% shows promise for enhancing duckweed productivity and optimizing nutrient reduction in wastewater from fish cultivation systems. This approach contributes to the promotion of sustainable integrated aquaculture.

Implementation of Augmented Reality Snap That Animal Using MDLC Method as Learning Media

This research introduces Snap That Animal, an augmented reality (AR) mobile application designed as an innovative educational tool for early childhood education. The study focuses on identifying challenges faced by teachers at Aisyiyah Bustanul Athfal Krajan Kindergarten when using traditional teaching methods to engage young learners. To address these challenges, the application was developed using the Multimedia Development Life Cycle (MDLC) method, incorporating the Vuforia SDK on the Android platform to create interactive 3D animal models activated by markers. This interactive approach aims to enhance student interest and learning outcomes by offering more engaging and accessible educational content. The app underwent thorough testing, including marker recognition under varying light intensities, tilt angles, and distances, as well as compatibility with different devices. Results demonstrated that the application performs efficiently in real-life educational settings. A quantitative descriptive approach was employed, with data collected through a questionnaire. The study population consisted of kindergarten teachers, and a total sample of nine teachers participated as respondents. The processed questionnaire results, evaluated using an assessment scale, revealed a feasibility rating of “very good,” with a score of 93.56%. In conclusion, the findings suggest that AR applications like Snap That Animal significantly enhance student engagement and learning effectiveness in early childhood education.

Biocompatibility of light responsive materials prepared for accommodative intraocular lenses manufacturing.

To investigate the biocompatibility and bacterial adhesion properties of light responsive materials (LRM) and analyze the feasibility and biosafety of employing LRM in the preparation of accommodative intraocular lenses (AIOLs). Employing fundamental experimental research techniques, LRM with human lens epithelial cells (hLECs) and human retinal pigment epithelium cells (ARPE-19 cells) were co-cultured. Commercially available intraocular lenses (IOLs) were used as controls to perform cell counting kit-8 (CCK-8), cell staining under varying light intensities, cell adhesion and bacterial adhesion experiments. LRM exhibited a stronger inhibitory effect on the proliferation of ARPE19 cells than commercially available IOLs when co-cultured with the undiluted extract for 96h (P<0.05). Under other culturing conditions, the effects on the proliferation of hLECs and ARPE-19 cells were not significantly different between the two materials. Under the influence of light irradiation at intensities of 200 and 300 mW/cm2, LRM demonstrated a markedly higher inhibitory effect on the survival of hLECs compared to commercially available IOLs (P<0.0001). They also showed a stronger suppressive effect on the survival rate of ARPE-19 cells, with significant differences observed at 200 mW/cm2 (P<0.001) and extremely significant differences at 300 mW/cm2 (P<0.0001). Additionally, compared to commercially available IOLs, LRM had a higher number of cells adhering to their surface (P<0.05), as well as a significantly greater number of adherent bacterium (P<0.0001). LRM, characterized by their excellent non-contact tunable deformability and low cytotoxicity to ocular tissues, show considerable potential for use in the fabrication of AIOLs. These materials demonstrate strong cell adhesion; however, during photothermal conversion processes involving shape deformation under various light intensities, the resultant temperature rise may harm surrounding cells. These factors suggest that while the material plays a positive role in reducing the incidence of posterior capsule opacification (PCO), it also poses potential risks for retinal damage. Additionally, the strong bacterial adhesion of these materials indicates an increased risk of endophthalmitis.

Anatomical adaptations of mangroves to the intertidal environment and their dynamic responses to various stresses.

Mangroves are intertidal plants that survive extreme environmental conditions through unique adaptations. Various reviews on diverse physiological and biochemical stress responses of mangroves have been published recently. However, a review of how mangroves respond anatomically to stresses is lacking. This review presents major mangrove anatomical adaptations and their modifications in response to dynamic environmental stresses such as high salinity, flooding, extreme temperatures, varying light intensities, and pollution. The available research shows that plasticity of Casparian strips and suberin lamellae, variations in vessel architecture, formation of aerenchyma, thickening of the cuticle, and changes in the size and structure of salt glands occur in response to various stresses. Mangrove species show different responses correlated with the diversity and intensity of the stresses they face. The flexibility of these anatomical adaptations represents a key feature that determines the survival and fitness of mangroves. However, studies demonstrating these mechanisms in detail are relatively scarce, highlighting the need for further research. An in-depth understanding of the structural adaptations of individual mangrove species could contribute to appropriate species selection in mangrove conservation and restoration activities.

Lighting Patterns Regulate Flowering and Improve the Energy Use Efficiency of Calendula Cultivated in Plant Factories with Artificial Lighting

Calendula is an edible flower with highly beneficial bioactive compounds for human health. Environmental factors such as light influence flower yield and quality. Calendula is cultivated under controlled environments in plant factories with artificial lighting (PFALs), which enhance its productivity. However, electricity is the main operating cost, with fees based on the time of use in some countries. This study aimed to investigate the effects of lighting patterns on calendula growth and yield. Two varieties of calendula seedlings were cultivated in a PFAL and subjected to six different lighting patterns, i.e., 6 h/6 h, 12 h/12 h, 6 h/2 h, and 18 h/6 h (light/dark) and two continuous lighting patterns with varying light intensities (24 h-200 and 24 h-400). The results indicated that plants cultivated under the 6 h/2 h, 18 h/6 h, 24 h-200, and 24 h-400 conditions showed a more rapid appearance of the first flower bud than those cultivated under the 6 h/6 h and 12 h/12 h conditions. The number of flowers and the fresh and dried weights tended to increase with a longer photoperiod. Interestingly, the total carotenoid content (TCC) of “Citrus Orange” increased under 6 h/6 h and 12 h/12 h conditions compared with the others. For “Orange Gem”, continuous lighting (24 h) increased the total phenolic content (TPC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in flowers compared with the 6 h/6 h 12 h/12 h, and 6 h/2 h treatments. The energy use efficiency (EUE) under the 24 h-200 condition was the highest in terms of flower yield and secondary metabolite production. These results suggest that lighting patterns can be used to modulate the growth and flowering of calendula and to maximize EUE.

Water use efficiency in tropical plants based on a set of newly created leaf photosynthesis-related parameters

Water use efficiency (WUE) quantifies the amount of water expended per unit of dry leaf matter accumulated, reflecting the trade-offs between water consumption and carbon uptake. It is also a critical parameter for understanding plant responses to environmental changes. This study introduced an innovative set of WUE-related parameters, including maximum water use efficiency (WUEmax) and associated coefficients of water potential, loss, strategic usage, and total usage (WPC, WLC, WSC, and WTC, respectively) in providing a comprehensive evaluation of water use strategies in 48 common tropical plant species during the natural light fluctuations. These parameters exhibited significant differences among plant types, with sun-adapted and shade-tolerant plants (both C3) showing mean of WUEmax values of 3.81 ± 0.63 and 5.42 ± 1.61 μmol mmol−1, respectively, whereas C4 plants demonstrated a greater WUEmax of 7.04 ± 1.77 μmol mmol−1. Compared to C3 plants, particularly shade-tolerant types, C4 plants exhibited significantly higher WPC and WTC (p < 0.05). Furthermore, shade-tolerant plants displayed lower WLC and higher WSC than sun-adapted plants, suggestive of their specialized adaptations to variations in light intensity. The sensitivity of stomatal and mesophyll conductance (i.e., gs and gm) to incident light (Iinc) and/or intercellular CO2 concentration (Ci) helped clarify the source of variation in WUE-related parameters. In sun-adapted plants, gs was sensitive to changes in both Iinc and Ci. In terms of gm, shade-tolerant plants exhibited the lowest overall sensitivity to Iinc. Increasing atmospheric CO2 concentrations from 400 to 450 ppm caused WUE-related parameters to vary, with this response differing among plant types. These insights emphasize the significance of plant adaptation strategies in tropical rainforest ecosystems.

Optimizing Light Intensity and Salinity for Sustainable Kale (Brassica oleracea) Production and Potential Application in Marine Aquaponics

With rising populations and increasing food consumption, the demand for food is placing significant strain on freshwater resources. Exploring crops that can thrive under saline conditions is crucial to ensuring food security. Although brackish and seawater is abundant, it is generally unsuitable for irrigation. However, some plants exhibit tolerance to moderate levels of salinity. This study investigated the effects of varying light intensities (150 and 250 photosynthetic photon flux densities) and salinity levels (&lt;1.5, 5, 10, and 17 parts per thousand, equivalent to &lt;26, 86, 171, and 291 millimolars) on the growth and nutrient composition of Russian kale (Brassica oleracea) grown in indoor hydroponics. The experiment was conducted over five months, from September 2023 to January 2024. The results revealed that a light intensity of 250 PPFD and salinity levels of &lt;1.5–5 ppt (&lt;26–86 mM) were optimal for maximizing the biomass yield of the kale, whereas a significant reduction in the yield was observed at salinity levels exceeding 10 ppt (171 mM). In contrast, the dry matter percentage was significantly higher at 17 ppt (291 mM). The macronutrient contents, particularly the total Kjeldahl nitrogen (TKN), total phosphorus (TP), and magnesium (Mg), were consistent across both light intensities (150–250 PPFDs) and at salinity levels between &lt;1.5 and 10 ppt (&lt;26–171 mM) but were reduced at 17 ppt (291 mM). The micronutrient concentrations, such as those of copper (Cu), iron (Fe), and zinc (Zn), were higher at the lower light intensity (150 PPFD) across the salinity levels. These findings suggest that optimizing the light conditions is essential for enhancing the nutritional value of kale in saline environments. These outcomes are particularly vital for improving agricultural productivity and resilience in salt-affected regions, thereby supporting broader food security and sustainability goals.

Shadow Removal for Enhanced Nighttime Driving Scene Generation

Autonomous vehicles depend on robust vision systems capable of performing under diverse lighting conditions, yet existing models often exhibit substantial performance degradation when applied to nighttime scenarios after being trained exclusively on daytime data. This discrepancy arises from the lack of fine-grained details that characterize nighttime environments, such as shadows and varying light intensities. To address this gap, we introduce a targeted approach to shadow removal designed for driving scenes. By applying Partitioned Shadow Removal, an enhanced technique that refines shadow-affected areas, alongside image-to-image translation, we generate realistic nighttime scenes from daytime data. Experimental results indicate that our augmented nighttime scenes significantly enhance segmentation accuracy in shadow-impacted regions, thereby increasing model robustness under low-light conditions. Our findings highlight the value of Partitioned Shadow Removal as a practical data augmentation tool, adapted to address the unique challenges of applying shadow removal in driving scenes, thereby paving the way for improved nighttime performance in autonomous vehicle vision systems.

Hydrogen peroxide concentration as an indicator of cyanobacterial response to diurnal variation in light intensity

We measured diurnal variations in oxidative stress conditions of cyanobacteria utilizing field observations and laboratory experiments in order to evaluate photoinhibition effects. On clear summer days, transparent bottles filled with surface water were set up at several depths and were collected every three hours together with the measurement of the photosynthetically active radiation (PAR). In the laboratory experiment, two cyanobacterial species were exposed to gradually increasing and then decreasing light intensities. The samples were analyzed with the PAR-induced (H2O2), along with the total hydrogen peroxide concentrations (total H2O2), the catalase activities (CAT), OD730, protein (Protein), and chlorophyll a (Chl a) contents, and so on. Protein was significantly proportionate with OD730 and Chl a, and was used as an indicator of cell biomass. Increasing PAR, H2O2 concentration increased proportionately with the PAR intensity. Then, an oxidative stress indicator in a cell, H2O2/Protein is given by the PAR divided by cell volume, evaluated by Protein. CAT activity in a cell, far largest among antioxidant activities, solely followed total H2O2/Protein. The prediction model for H2O2/Protein was developed with the sufficient agreement with the experimental and field observation results. The model elucidated that the maximum H2O2/Protein in a day was larger with lower cell density even at the water surface, indicating that the higher photoinhibition was imposed at low density, in addition to the lower attenuation of PAR. These results indicate that H2O2/Protein is an effective biomarker to indicate the stress level of cyanobacteria; the observed levels of H2O2 to freshwater may prove useful in designing the criteria for cyanobacteria management.

Research and Design of an Active Light Source System for UAVs Based on Light Intensity Matching Model

The saliency feature is a key factor in achieving vision-based tracking for multi-UAV control. However, due to the complex and variable environments encountered during multi-UAV operations—such as changes in lighting conditions and scale variations—the UAV’s visual features may degrade, especially under high-speed movement, ultimately resulting in failure of the vision tracking task and reducing the stability and robustness of swarm flight. Therefore, this paper proposes an adaptive active light source system based on light intensity matching to address the issue of visual feature loss caused by environmental light intensity and scale variations in multi-UAV collaborative navigation. The system consists of three components: an environment sensing and control module, a variable active light source module, and a light source power module. This paper first designs the overall framework of the active light source system, detailing the functions of each module and their collaborative working principles. Furthermore, optimization experiments are conducted on the variable active light source module. By comparing the recognition effects of the variable active light source module under different parameters, the best configuration is selected. In addition, to improve the robustness of the active light source system under different lighting conditions, this paper also constructs a light source color matching model based on light intensity matching. By collecting and comparing visible light images of different color light sources under various intensities and constructing the light intensity matching model using the comprehensive peak signal-to-noise ratio parameter, the model is optimized to ensure the best vision tracking performance under different lighting conditions. Finally, to validate the effectiveness of the proposed active light source system, quantitative and qualitative recognition comparison experiments were conducted in eight different scenarios with UAVs equipped with active light sources. The experimental results show that the UAV equipped with an active light source has improved the recall of yoloV7 and RT-DETR recognition algorithms by 30% and 29.6%, the mAP50 by 21% and 19.5%, and the recognition accuracy by 13.1% and 13.6, respectively. Qualitative experiments also demonstrated that the active light source effectively improved the recognition success rate under low lighting conditions. Extensive qualitative and quantitative experiments confirm that the UAV active light source system based on light intensity matching proposed in this paper effectively enhances the effectiveness and robustness of vision-based tracking for multi-UAVs, particularly in complex and variable environments. This research provides an efficient and computationally effective solution for vision-based multi-UAV systems, further enhancing the visual tracking capabilities of multi-UAVs under complex conditions.