Light Conditions Research Articles

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 (<1.5, 5, 10, and 17 parts per thousand, equivalent to <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 <1.5–5 ppt (<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 <1.5 and 10 ppt (<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.

Solar-Driven Agri Bot: A Storage-Free, Eco-Friendly Farming Solution

This work presents an innovative solution for sustainable agriculture by utilizing solar power to directly drive its motor system without the need for energy storage. This bot is equipped with Light Dependent Resistors (LDRs) and an Arduino microcontroller, the bot adjusts motor operations based on light conditions for optimal power efficiency. A relay switch enables seamless switching between solar power and a backup battery, ensuring continuous operation in varying sunlight. The bot’s multi-motor design supports reliable movement, accommodating a range of agricultural tasks such as transporting loads, water spraying, and ploughing. Its trolley adds versatility for carrying goods, making it practical and multifunctional in the field. This eco-friendly system not only reduces energy waste but also minimizes costs and design complexity by foregoing energy storage. Offering a cost-effective, environmentally-friendly solution for modern agriculture, this bot demonstrates a valuable application of direct solar power in field operations, supporting greener, more sustainable farming practices.

The effect of blue and UV light-emitted diodes (LEDs) on the disturbance of the whitefly natural enemies Macrolophus pygmaeus and Encarsia formosa

Recent studies demonstrated that blue and UV light effectively disturb greenhouse whiteflies (Trialeurodes vaporariorum) from a host plant (“push”), enhancing their capture on attractive traps after dispersal (“pull”). This push–pull technique could contribute to whitefly biocontrol and lead to the development of mass trapping. However, the impact of these wavelengths on the behavior of whitefly natural enemies, commonly deployed for biocontrol, remains underexplored. This study investigated the response of two important whitefly biocontrol agents, Macrolophus pygmaeus and Encarsia formosa, to blue and UV light. Initial experiments were conducted under artificial conditions (no prey/host and plant present) to isolate their visual behavior to these lights, excluding other stimuli. In follow up experiments, the effect of these lights was assessed in a more complex scenario, involving prey/host (whitefly nymphs) on tomato leaves. Results revealed that both M. pygmaeus and E. formosa exhibited avoidance behavior under blue and UV LEDs in the artificial setup, irrespective of ambient light or dark conditions. Contrastingly, in presence of prey/host on tomato leaves, only M. pygmaeus was significantly disturbed by UV light, whereas in all other scenarios there was little to no effect of blue and UV LEDs on the behavior of these natural enemies.. These findings enhance our understanding on the visual behavior of crucial biocontrol agents and highlight the importance of refining targeted whitefly control techniques that minimize impacts on beneficial insects and optimize the use of LEDs in integrated pest management (IPM).

Phototactic signaling network in rod-shaped cyanobacteria: A study on Synechococcus elongatus UTEX 3055

Light-controlled motility is advantageous for photosynthetic prokaryotes to better survive in environment with constantly changing light conditions. For cyanobacteria, light is both an energy source for photosynthesis and a stress factor. Consequently, some cyanobacteria evolved the ability to control type-IV pili (T4P)-mediated surface motility using a chemotaxis-like system in response to light signals. Extensive studies on the mechanism of phototaxis has been conducted in the spherical Synechocystis sp. PCC 6803 and the filamentous strain Nostoc punctiforme, while less is explored in rod-shaped cyanobacteria such as Synechococcus species. In this study, we investigated the phototaxis pathway in the unicellular rod-shaped cyanobacterium Synechococcus elongatus UTEX 3055, which exhibits bidirectional phototaxis using a single tax1 operon, in contrast to more complex and multiple gene clusters revealed in Synechocystis sp. PCC 6803. Results obtained by protein-protein interaction assays and protein subcellular localization experiments indicated that proteins encoded by the tax1 operon form large clusters that asymmetrically distributed both between the two poles and within the same pole. In vitro phosphorylation assays and site-directed mutations of conserved phosphorylation sites in PixLSe, PixGSe and PixHSe demonstrate that PixLSe acts as a histidine kinase, and PixGSe and PixHSe as response regulators for signal transduction. We further show that PixGSe and PixHSe are recruited to cell poles via interactions with the N-terminal region of PixLSe. While phosphotransfer reactions in this signaling pathway are critical for phototactic signaling, the two response regulators appear to play different roles in the control of phototaxis. This study provides a framework for further investigation into the complex phototactic signaling network in rod-shaped cyanobacteria with clearly defined cell poles in contrast to round shaped Synechocystis species with virtual cells poles through light-lensing effect.

Effects of Pulsed Electric Fields on the Elimination of Fusarium oxysporum in Greenhouse Soil

In greenhouses, high humidity, low light, and inadequate ventilation conditions, along with continuous and high-density planting, promote the proliferation of soilborne pathogens. Among these pathogens, Fusarium oxysporum Schltdl (F. oxysporum) is a notably challenging one, causing root rot of tomato plants in greenhouse cultivation. To address this issue, this study applied a pulsed electric field (PEF) to target the elimination of F. oxysporum in suspension and soil media. Initially, PEF parameters were systematically explored in suspensions to determine the effective ranges for the elimination of F. oxysporum. The results revealed that the effective ranges for achieving the desired microbial reduction were an electric field strength (EFS) between 5–15 kV·cm−1, a pulse number within the range of 100–500, and a pulse width of 10–20 µs. Subsequently, the impact of soil moisture content, soil bulk density, and soil type on soil dielectric breakdown field strength was analyzed within the range from previous results. Based on these findings, the soil experiments were conducted with parameters designed to prevent dielectric breakdown. Specifically, for sampling soil with a moisture content of 16.2% and a bulk density of 1.31 g·cm−3, the maximum effective application of electric field strength was 9.5 kV·cm−1, accompanied by 1000 pulses and a pulse width of 20 µs. Finally, building on these results, soil samples were sterilized within a parameter range that spanned an electric field strength of 5–9.5 kV·cm−1, a pulse number between 100–500, and a pulse width of 10–20 µs. Response surface methodology (RSM) analysis further identified the optimal parameter combination: an electric field strength of 8.2 kV·cm−1, 306 pulses, and a pulse width of 15 µs, resulting in an average lethal rate of 76.16% for F. oxysporum sterilization in soil. These findings suggest the potential use of PEF against F. oxysporum and other pathogens in greenhouse soils, and provide theoretical foundations for further experiments, thereby contributing to the sustainable advancement of greenhouse agriculture.

A REVIEW OF Solar Panel Efficiency: The Influence of Installation Angles and Design

This contrasts performance under different conditions of air, how these solar cell technologies can optimize solar energy conversion efficiency in specific locations. The intention of this information on the best applications is to consider cost, efficiency, and environmental considerations. These findings of the present study will contribute to ongoing efforts at making solar energy use better and more efficient, thereby accelerating the transition towards a greener energy future. All these technologies, including monocrystalline, polycrystalline, thin-film, and Passivated Emitter and Rear Cell (PERC) solar cells, have been developed to convert the energy received from the sun efficiently. As far as conversion efficiency is concerned, every technology has its plus points and negative points, especially in different climatic situations. These monocrystalline solar cells are known for their great endurance and efficiency in functioning remarkably well, even in hot and sunny conditions. Even though not as efficient as the monocrystalline counterparts, polycrystalline solar cells are still affordable and work satisfactorily in temperate climates. With their flexibility and low weight, thin-film solar cells work well with low light conditions and may be applied in many applications, such as building-integrated photovoltaics. They have greater capacity for absorbing light and lesser electron. Keywords: monocrystalline, polycrystalline, thin-film, and PERC (Passivated Emitter and Rear Cell).

EFFECTS OF HYPOTHERMIC STRESS APPLIED TO SEEDS BEFORE GERMINATION ON THE PARAMETERS OF THE PHOTOSYNTHETIC APPARATUS OF MAIZE PLANTS

In maize (Zea mays L.) plants grown from seeds pre-treated with negative temperature stress (NTS) of -4°C for 16 hours before germination, followed by growth in dark and light conditions, the content of chlorophyll pigments (Chl) in leaves, the chlorophyll content index (CCI) and some gas exchange parameters were assessed. Combined application of NTS and illumination conditions to seedling growth showed that 6-day-old NTS maize seedlings grown in the dark were etiolated, contained carotenoids and traces of Chl a and Chl b. Whereas in green seedlings grown in the light, NTS decreased Chl a, Chl b and carotenoids. NTS also reduced the CCI in1st, 2nd and 3ed leaves of plants grown in the light for 17 days. While in the 1st, 2nd and 3ed leaves of control plants that grew in the light, the CCI changed dynamically, showing a maximum on the 9th day of growth and then decreased. The influence of NTS also affected the parameters of gas exchange in leaves, causing a decrease in CO2 exchange, real CO2 absorption and total respiration.

White LED intensities during co-cultivation affect the Agrobacterium-mediated soybean (Glycine max) transformation using mature half seeds as explants.

The transition of light fixture from fluorescent light to light-emitting diodes (LEDs) in growth chambers prompts a reevaluation of current practices in plant biotechnology. Agrobacterium-mediated transformation is crucial for genetic engineering and genome editing in soybean (Glycine max). The critical co-cultivation step of soybean transformation occurs under light condition. Current protocols for co-cultivation in soybean transformation lack a standard for light intensity. In the present study, the objective is to investigate the effect of light intensity during co-cultivation on soybean transformation efficiency. Five light intensities were implemented during five days of co-cultivation: 50, 100, 150, 190 μmol∙m-2∙s-1 of white LEDs in addition to 100 μmol∙m-2∙s-1 of fluorescent light. After co-cultivation, all the explants underwent shoot induction and elongation with selection pressure, rooting and acclimation under uniform condition. The experiment was conducted with two selectable markers, hppdPf-4Pa and bar, separately, investigating whether the potential light effects vary due to the marker-associated pathways. The positive PCR analysis of rooted in vitro plants suggested successful transformation events achieved under both selectable markers across all light treatments ranging from 2.4% to 6.9%. Increasing LED light intensity during co-cultivation resulted in different transformation efficiencies between the two selectable markers. Results indicated that increasing the light intensity during co-cultivation led to a linear increase in transformation efficiency when shoot regeneration was under 4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor selection. No difference in transformation efficiency was detected among the treatments under glufosinate selection. Furthermore, when selection occurred with HPPD inhibitor, variation of transformation efficiency was also observed between fluorescent light and white LED at 100 μmol∙m-2∙s-1. The results highlight the significance and potential applications of investigating the impact of light on transformation efficiency.

Germination, seed traits, and seedling vigor of Pilosocereus robinii (Cactaceae) from northwestern Cuba

Studies on the germination of Caribbean cacti are essential for conservation and ecological restoration programs. We evaluated the seed traits and germination response of Pilosocereus robinii under five temperatures and two light conditions and compared the vigor of the seedlings obtained. Seminal traits showed characteristics of orthodox seeds. Pilosocereus robinii seeds showed positive photoblastism and a range of optimal temperatures below 30°C. In all treatments where germination was suboptimal, the seeds demonstrated high recovery percentages when they were exposed to the optimal temperature. The vigor of the seedlings showed a behavior similar to germination. Our study shows that restoration plans for the species' populations are viable from seeds.

Phenotypic plasticity does not prevent impairment of aboveground biomass production due to increased light and water deficit in Dimorphandra exaltata, an endangered species.

Phenotypic plasticity may allow plant species to cope with environmental variability that influences plant growth and may limit the distribution of a species. The present study investigated the morphophysiology and phenotypic plasticity responses due to light and water variability of young Dimorphandra exaltata plants, an endemic threatened tree from the Atlantic Forest. After emergence, plants were grown in two light conditions: shading (70%) and full sun. At 160days old, we measured chlorophyll a fluorescence, chlorophyll indices, and biomass allocation. Afterward, the plants were subdivided into two water regimes: irrigation vs suspension of irrigation. At 310days old, morphophysiological measurements and stem water potential were taken. D. exaltata plants showed higher specific leaf area (SLA, 160days old) and chlorophyll b (310days old) under shading. Over time, plants under shading showed a decrease in SLA. Also, there was a decrease in the leaf area ratio in both light treatments and an increase in the phenotypic plasticity index. Even showing morphological adjustments to light and water deficit, the higher biomass allocation to roots at the expense of the aboveground part could impair the growth of young plants in understory areas. The phenotypic plasticity presented by D. exaltata does not guarantee that the species can withstand severe disturbance while maintaining normal development. Therefore, it is important to understand the effects of ecosystem fragmentation and water variation and their impacts on the maintenance of species in their areas of occurrence, especially endangered species such as D. exaltata.

Synthesis and marine antifouling properties of carbazole amide derivatives with fluorescent properties and their zinc acrylate resins

Fluorescent antifouling is a method that utilizes substances fluorescent repellent effect to prevent organisms attachment and fouling. It is considered one of the directions for developing environmentally friendly marine antifouling materials. The current fluorescent antifouling materials were characterized by issues such as single functionality, unclear antifouling mechanisms, and suboptimal antifouling performance. In this study, three carbazole derivatives containing carbon–carbon double bonds were synthesized by Friedel-Crafts alkylation reaction, and a series of zinc acrylate resins containing carbazole derivative structures were further synthesized through free radical polymerization. Three carbazole derivatives were tested for their fluorescence and their growth inhibition properties against bacteria and algae. The results showed that the three carbazole derivatives not only had high fluorescence intensity, but also had good inhibitory effects on bacteria and algae, with the highest inhibition rate of 81% on algae. The fluorescence properties, algal inhibition properties and anti-algal adhesion properties of the resin were investigated. The results showed that the fluorescence intensity of the resin was enhanced with the increase of carbazole derivative content. The inhibition rate of the resin against algae was as high as 88.5%, and the anti-algal adhesion rate of the resin was improved under light conditions. Mechanistic studies showed that the resin influenced the cell wall, and the fluorescence caused the algae to prioritize photosynthesis rather than attachment and settlement. Self-polishing performance test results showed that the introduction of carbazole derivatives improved the stability of the resin. The results of the real sea antifouling test show that the resin integrates fluorescence, chemical activity and self-polishing, and has excellent antifouling performance. This provides a theoretical basis for the development of environmentally friendly marine antifouling materials.

Spatiotemporal bifurcation of HY5-mediated blue-light signaling regulates wood development during secondary growth

Plants have evolved photoreceptors to optimize their development during primary growth, including germination, hypocotyl elongation, cotyledon opening, and root growth, allowing them to adapt to challenging light conditions. The light signaling transduction pathway during seedling establishment has been extensively studied, but little molecular evidence is available for light-regulated secondary growth, and how light regulates cambium-derived tissue production remains largely unexplored. Here, we show that CRYPTOCHROME (CRY)-dependent blue light signaling and the subsequent attenuation of ELONGATED HYPOCOTYL 5 (HY5) movement to hypocotyls are key inducers of xylem fiber differentiation in Arabidopsis thaliana. Using grafted chimeric plants and hypocotyl-specific transcriptome sequencing of light signaling mutants under controlled light conditions, we demonstrate that the perception of blue light by CRYs in shoots drives secondary cell wall (SCW) deposition at xylem fiber cells during the secondary growth of hypocotyls. We propose that HY5 is a blue light–responsive mobile protein that inhibits xylem fiber formation via direct transcriptional repression of NAC SECONDARY WALL THICKENING PROMOTING 3 ( NST3 ). CRYs retain HY5 in the nucleus, impede its long-distance transport from leaf to hypocotyl, and they initiate NST3- driven SCW gene expression, thereby triggering xylem fiber production. Our findings shed light on the long-range CRYs-HY5-NST3 signaling cascade that shapes xylem fiber development, highlighting the activity of HY5 as a transcriptional repressor during secondary growth.

Functions of MdTINY, a member of the apple dehydration responsive element binding-A4

The dehydration responsive element binding (DREB) transcription factors play an important role in plant growth and development and are extensively involved in plant responses to abiotic stress. The DREB family contains six subfamilies, and TINY belongs to the DREB-A4 subfamily. The Arabidopsis thaliana TINY gene, AtTINY, plays a role in regulating plant growth and responses to stress. In order to investigate the evolutionary characterization of the DREB-A4 subfamily and the biological function of the MdTINY gene in apple (Malus domestica), in this study, we used the databases GDDH13 and TAIR and online tools (Expasy and WoLF PSORT) to study the biological information of the DREB-A4 subfamily in apple. In addition, the tertiary structures of the proteins were predicted. The apple DREB-A4 subfamily contained 22 genes, all of which had a conserved AP2 domain, and subcellular localization predictions showed that DREB-A4 subfamily proteins were mainly located in the nucleus. The transgenic calli of MdTINY were obtained by the Agrobacterium-mediated transformation method, and the main biological functions of MdTINY were explored by quantitative real-time PCR (qRT-PCR) combined with anthocyanin content determination. MdTINY shared the highest amino acid sequence similarity with AtTINY. The coding region of MdTINY had a full length of 759 bp, encoding 252 amino acid residues. Analysis of the promoter elements and expression patterns indicated that MdTINY was responsive to light and multiple stress conditions. MdTINY was localized in the nucleus and had transcriptional autoactivation activity. The overexpression of MdTINY in calli inhibited normal growth and promoted anthocyanoside accumulation. These results indicated that MdTINY negatively regulated apple plant growth and promoted fruit coloring, providing a candidate gene for the breeding of apple varieties with high quality of fruit color.

Phenothiazine‐Modified PTAA Hole Transporting Materials for Flexible Perovskite Solar Cells: A Trade‐Off Between Performance and Sustainability

AbstractHole Transport Materials (HTMs) are one of the key elements in Perovskite Solar Cells (PSCs) and specifically polymeric HTMs have recently emerged as one of the most viable options to couple excellent performance and good stability. However, most are processed only in aromatic solvents (e.g., toluene or chlorobenzene), thus negatively impacting the overall sustainability of the device. In this contribution, four novel polymers are synthesized specifically designed to be processable in less harsh, non‐aromatic, and non‐chlorinated solvent (i.e., Tetrahydrofuran – THF): the conventional PTAA scaffold is modified by the insertion of a phenothiazine (PTZ) and by the modulation of the methyl moieties on the peripheral benzene. Alternatively, a benzothiadiazole moiety is also added. The polymers are then implemented in flexible PSCs (F‐PSCs) that have recently attracted increased attention due to their high power‐to‐weight ratio. The THF‐processed P1 (a PTZ‐PTAA copolymer with one methyl group substituted) reaches an overall efficiency of 9.10%, outperforming THF‐processed PTAA (PCE = 8.25%) and approaching the one of toluene‐processed reference (PCE = 9.30%). Furthermore, P1 shows better stability under light soaking conditions. To rationalize these results, different characterizations are presented, including optoelectronic techniques, thermal and surface analyses, and GWAXS measurements.

Genomic insights into the alphaproteobacterium Georhizobium sp. MAB10 revealed a pathway of Mn(II) oxidation-coupled anoxygenic photoautotrophy: a novel understanding of the biotic process in deep-sea ferromanganese nodule formation.

Microorganisms are believed to participate in the biotic process of deep-sea ferromanganese nodule formation [Mn(II) oxidation]. Despite the multitude of studies and reviews focusing on the details of Mn(II) oxidation catalyzed by diverse heterotrophs, the mechanistic roles of manganese chemolithotrophs from ferromanganese nodules remain unclear. We demonstrate that strain Georhizobium sp. MAB10 can utilize Mn(II)-derived electrons for photoautotrophic growth, with concomitant generation of dark β-MnO2 type Mn oxides under near-infrared light condition. This study uses genomic and biochemical assays to explore the genetic basis of Mn(II) oxidation-coupled anoxygenic photoautotrophy. The comprehensive analyses of respiration and carbon and nitrogen metabolism further elucidated the high ecophysiological flexibility of strain MAB10 in deep-sea habits. These findings expand our understanding of the role of chemolithotrophs in deep-sea ferromanganese nodule formation and justify further investigations into the molecular basis for Mn(II) oxidation-coupled anoxygenic photoautotrophy.

Effect of northwestern photoperiod and exogenous melatonin on the psychoemotional state of the Syrian hamsters (Mesocricetus auratus)

Background. Among the environmental factors that influence the increase in the frequency of occurrence of psychoemotional states, great importance is attributed to the light conditions. However, the mechanisms of behaviour regulation in the mammals in non-standard light conditions and the role of melatonin in this process have not been fully studied.The aim of the study. To assess the effects of specific northern light conditions and melatonin on the behavior of Mesocricetus auratus.Methods. The animals were divided into 4 groups: LD (control), NL (northern light conditions), and LD + mel and NL + mel (melatonin, 100 μg/animal). The study of behavioral reactions, the level of emotional and phobic anxiety state of animals was carried out in the “Open field” and “Dark chamber with holes” installations.Results. Keeping M. auratus in NL had a negative effect on their behavior – a decrease in motor activity (horizontal and vertical) and the “hole-exploratory behavior”, an increase in the number of freezing and grooming reactions and the time of the first peeking out of the upper hole were revealed. It was shown that melatonin contributed to an increase in exploratory activity and a decrease in the number of anxiety acts in NL + mel group compared to NL group; the opposite effect of the hormone on these parameters was observed in LD + mel group.Conclusion. The obtained results indicate the important role of photoperiod and melatonin in regulating the behavior of seasonally breeding species.

Deadwood manipulation and type determine assemblage composition of saproxylic beetles and fungi after a decade

The biodiversity crisis calls for immediate restoration of deteriorated and rare habitat. Due to fire suppression and intensive forest management, boreal pine forests of high conservation value are exceptionally rare. Despite decades of restoration research in boreal forests, relatively few studies have evaluated multi-taxon biodiversity response of restoration measures in pine forests. In a Scots pine experiment, we investigated biodiversity patterns of wood-inhabiting fungi and beetles a decade after restoration (prescribed burning and deadwood creation) and forest management (harvest with varying retention). We found that fungi and beetles develop differently and have distinct preferences in deadwood originating from restoration. Standing deadwood supported more species for beetles and lying deadwood for fungi and for both taxa, standing and lying deadwood harboured different species assemblages. Burned deadwood displayed less variable assemblages than unburned deadwood for both organism groups. We found that, after a decade, deadwood type and not harvest with different retention levels better explained diversity patterns of wood-inhabiting beetles and fungi in pine forests. Pine forests are naturally prone to recurring disturbances creating open light conditions. Pine-associated species are therefore likely resistant to disturbance as long as a variety of deadwood resources are present. To accommodate multiple taxa, a variety of substrate and environment types is required. Beetles benefit from standing deadwood while fungi benefit from lying deadwood. To support assemblages with both rapid and slow turnover rates, a combination of recurring restoration and leaving restored stands in the adjacent landscapes is required.

Fabrication of organic/inorganic reactive composites for fast removal of arsenic species from groundwater systems

This study investigates the catalytic potential of anionic MnO2 nanosheets (Mn), a cationic covalent organic Framework (COF), and their composites (CM, C2M, and CM2) with varying Mn weight percentages for arsenic removal from groundwater. The catalysts were used as activators of sodium sulfite (SS) under light conditions, enabling the pre-oxidation of arsenic (III) (As3) to arsenic(V) (As5), followed by the adsorption of As5 for complete arsenic removal from water. The Mn-COF-SS systems (C2M, CM, CM2) exhibited superior performance compared to Mn and COF alone, highlighting the dual functionality of the composites as both oxidizing agents and effective adsorbents for arsenic species. Among the composites, CM2 with 32 wt% Mn demonstrates exceptional efficiency, achieving 99.99 % arsenic removal within 30 min. The sorption process in a batch reactor was pH-dependent, with sulfate radicals (SO4-) and electrostatic interactions playing key roles in As3 oxidation and As5 removal, respectively. The pseudo-second-order kinetic model was found to be the dominant model for the sorption process, and the sorption process was compatible with the Freundlich isotherm model, which indicates a multilayer adsorption process of arsenic species on CM2. The practical application of CM2 in a fixed-bed reactor showed its high efficiency for arsenic removal, achieving the contaminant level below 10 ppb as recommended by WHO. This project highlights the potential of CM2 as an effective catalyst for arsenic removal, offering a promising approach to mitigating arsenic contamination in water sources.

Interface structure of PN junctions in NiO–WO3–FTO photoelectrode for efficient DSSCs and enhanced photoresponses

In the current global energy crisis, dye-sensitized solar cells (DSSCs) with excellent performance and loaded with P/N type semiconductor heterojunctions (PN junctions) has attracted huge attention in renewable energy research. This study reports the unique energy level structure and synergistic effect of the PN junction interfaces in response to light. Photoelectrodes containing NiO–WO3 nano-powder (NPs) layers were synthesized on fluorine-doped tin oxide (FTO) substrates by a simple method, which can respond to full-spectrum absorption of sunlight. In this study, the carrier densities in the P-type and N-type semiconductor heterojunctions at a light intensity of 2 SUN (2000 W/m2) were 1.38 × 1028 m−3 and 4.27 × 1028 m−3, respectively. These values are 2.7 and 1.9 times higher than those in dark conditions, indicating that the electrode excels in converting light into electrical energy, outperforming other reported results. Although PN junctions are often used in applications such as DSSCs and energy storage devices, the photoresponses of the heterojunction energy band structure still need to be elucidated. In this work, the analysis of the charge depletion region width revealed the electron transfer mechanism during the charge and discharge process under light illumination. Additionally, the electrochemical experiment demonstrated the impact of space charge at the interface on the energy levels. Furthermore, by studying the energy level structure of the PN junction, it was confirmed that the internal resistance decreases and the photocurrent increases under light conditions. The design and application flexibility of the PN junctions were verified based on these results and the possible applications of this photoelectrode in solar cells were elucidated.

Decapsulation of artemia cysts (Artemia sp.) using different versions of sodium hypochlorite solutions (NaOCL)

The article describes the technology of Artemia decapsulation, its features and external factors affecting the efficiency of hatching with subsequent use as a feed composition. Artemia nauplii and its eggs, due to their high nutritional value and high digestibility in the digestive tract, are widely used in growing sturgeon larvae and other fish species. Artemia decapsulation is one of the most important factors in the transition of fish larvae to active feeding, in this regard, it is very important to select the optimal decapsulation conditions, the composition of chemical reagents, temperature and light conditions. The decapsulation process is a chemical process of removing the hard shell that surrounds the Artemia embryo. The procedure involves hydration, during which the outer shell is removed, can be carried out with a number of solutions: sodium hydroxide, sodium carbonate, sodium hypochlorite, hydrochloric acid. However, they all show different availability and efficiency in decapsulation. The most common is the use of sodium hypochlorite solutions, but they do not show stable results, since the process of decapsulation and hatching of nauplii from cysts depends on many factors. The aim of the work was to study the methods of decapsulation of Artemia eggs for their use as a starter feed when transferring to active feeding and feeding of sturgeon larvae. As a result of the experiments, a technology for incubating Artemia eggs in accessible conditions without the use of professional equipment was developed. Cysts are incubated in aerated Weiss apparatuses, under constant illumination, in a volume of 7 liters of water, at a concentration of: NaCl — 30%, artemia cysts 3 g/l, water temperature — 28 °С. The cysts are decapsulated without soaking, with 2.5% NaOCl solution with a total volume of 300 ml (21 g of dry cysts + 150 ml of water + 150 ml of NaOCl) for 4–5 minutes.