Lighting Energy Use Research Articles

Light Energy Use Efficiency in Photosystem II of Tomato Is Related to Leaf Age and Light Intensity

The fundamental key to increase photosynthetic efficiency of crop plants lies in optimizing the light energy use efficiency. In our study, we used tomato to evaluate the allocation of absorbed light energy in young and mature leaves, and to estimate if the extent of photoinhibition and photoprotection can be affected by the leaf age. A reduced efficiency of the oxygen-evolving complex, in young leaves compared to mature ones, resulted in a donor-side photoinhibition, as judged from the significantly lower Fv/Fm ratio, in young leaves. The detected increased 1O2 production in young leaves was probably due to a donor-side photoinhibition. The effective quantum yield of photosystem II (PSII) photochemistry (ΦPSII), at low light intensity (LLI, 426 μmol photons m−2 s−1), was significantly lower in young compared to mature leaves. Moreover, the non-significant increase in non-photochemical energy loss in PSII (ΦNPQ) could not counteract the decreased ΦPSII, and as a result the non-regulated energy loss in PSII (ΦNO) increased in young leaves, compared to mature ones. The significantly lower ΦPSII in young leaves can be attributed to the increased reactive oxygen species (ROS) creation that diminished the efficiency of the open PSII reaction centers (Fv’/Fm’), but without having any impact on the fraction of the open reaction centers. The reduced excess excitation energy, in mature leaves compared to young ones, at LLI, also revealed an enhanced PSII efficiency of mature leaves. However, there was almost no difference in the light energy use efficiency between young and mature leaves at the high light intensity (HLI, 1000 μmol photons m−2 s−1). The ability of mature tomato leaves to constrain photoinhibition is possible related to an enhanced photosynthetic function and a better growth rate. We concluded that the light energy use efficiency in tomato leaves is influenced by both the leaf age and the light intensity. Furthermore, the degrees of photoinhibition and photoprotection are related to the leaf developmental stage.

Recent Advances in the Utilization of Chiral Covalent Organic Frameworks for Asymmetric Photocatalysis.

The use of light energy to drive asymmetric organic transformations to produce high-value-added organic compounds is attracting increasing interest as a sustainable strategy for solving environmental problems and addressing the energy crisis. Chiral covalent organic frameworks (COFs), as porous crystalline chiral materials, have become an important platform on which to explore new chiral photocatalytic materials due to their precise tunability, chiral structure, and function. This review highlights recent research progress on chiral COFs and their crystalline composites, evaluating their application as catalysts in asymmetric photocatalytic organic transformations in terms of their structure. Finally, the limitations and challenges of chiral COFs in asymmetric photocatalysis are discussed, with future opportunities for research being identified.

Manipulation of defect state emission in Zn chalcogenide quantum dots and their effects on chlorophyll spectral response

Water soluble Zn based quantum dots (QDs) are of interest due to their biocompatibility and less toxic features. They have been frequently used in studies related to biotechnology, especially in agriculture studies. However, to control the optical properties of Zn based QDs has still been a challenge. In this work, the defect state emission of ZnSe QDs was successfully controlled through two different routes; 1) By creating a sulfur rich outer region around the Se rich core 2) By changing the capping agent. Gradient alloyed ZnSeS QDs with Se rich core and S rich outer region were successfully synthesized with two different capping agents; N-Acetyl-L-Cysteine (NAC) and 3-Mercaptopropionic Acid (3-MPA). The contribution of emission originated from surface-defects almost disappeared in NAC capped ZnSeS QDs, with causing a significant increase in photoluminescence quantum yield. The interaction between Zn based QDs with chlorophyll molecules was also investigated. The absorption capacity of chlorophylls significantly enhanced upon interaction with 3-MPA capped ZnSeS QDs. Also, the spectral response of chlorophylls could be modulated through interaction with 3-MPA capped ZnSeS QDs, which could be manipulated by using ZnSeS QDs with different chemical composition. Our results indicated that ZnSeS QDs have potential to be used in agriculture, which could act as a modulator of light-harvesting capacity of chlorophylls. The ability to modulate chlorophyll spectral responses through QD interaction opens new possibilities for optimizing light utilization in photosynthetic organisms, thereby contributing to enhanced crop yields and more efficient use of light energy in natural and artificial ecosystems.

An endogenous oxygen self-supplied nanoplatform with GSH-depleted and NIR-II triggered electron-hole separation for enhanced photocatalytic anti-tumor therapy.

The use of artificial enzymes and light energy in photocatalytic therapy, a developing drug-free therapeutic approach, can treat malignant tumors in vivo. However, the relatively deficient oxygen concentration in the tumor microenvironment (TME) restrains their further tumor treatment capability. Herein, a novel nanoplatform with Cu7S4@Au nanocatalyst coated by MnO2 was successfully designed. After 1064 nm light irradiation, the designed nanocatalyst can promote the separation of light generated electron-hole pairs, resulting in ROS generation and tumor cell apoptosis. The MnO2 shelled nanoplatform can function as a TME-responsive oxygen self-supplied producer to improve photocatalyst treatment and GSH depletion. In summary, the designed novel nanoplatform shows efficient inhibition of tumor growth via GSH depletion and synergistic photocatalytic therapy, which is of great significance for improving the clinical tumor treatment effect.

Modifying the Ambient Light Spectrum Using LED Lamps Alters the Phenolic Profile of Hydroponically Grown Greenhouse Lettuce Plants without Affecting Their Agronomic Characteristics.

The growth and development of green lettuce plants can be modulated by the prevailing light conditions around them. The aim of this study was to evaluate the effect of ambient light enrichment with different LED light spectra on agronomic characteristics, polyphenol concentration and relative gene expression of enzymes associated with polyphenol formation in 'Levistro' lettuce grown hydroponically in a Nutrient Film Technique (NFT) system for 28 days in a greenhouse. The spectra (blue:green:red:far-red) and red:blue (R:B) ratios obtained by enriching ambient light with Blue (B), White (W), Blue-Red (BR) and Red (R) LED light were B: 47:22:21:10, 0.5:1; W: 30:38:23:9, 0.8:1; BR: 33:15:44:8, 1.3:1 and R: 16:16:60:8, 3.8:1, respectively, and photosynthetically active radiation (PAR) under the different treatments, measured at midday, ranged from 328 to 336 µmoles m-2 s-1. The resulting daily light integral (DLI) was between 9.1 and 9.6 mol m-2 day-1. The photoperiod for all enrichment treatments was 12 h of light. The control was ambient greenhouse light (25:30:30:15; R:B = 1.2:1; PAR = 702 µmoles m-2 s-1; DLI = 16.9 mol m-2 day-1; photoperiod = 14.2 h of light). Fresh weight (FW) and dried weight percentage (DWP) were similar among the enrichment treatments and the control. The leaf number increased significantly under BR and R compared to B lights. The relative index of chlorophyll concentration (RIC) increased as plants grew and was similar among the enrichment treatments and the control. On the other hand, the concentration of chlorogenic acid and chicoric acid increased under BR and B lights, which was consistent with the higher relative expression of the coumarate 3-hydroxylase enzyme gene. In view of the results, it is inferred that half of the PAR or DLI is sufficient to achieve normal growth and development of 'Levistro' lettuce plants, suggesting a more efficient use of light energy under the light enrichment treatments. On the other hand, the blue and combined blue-red lights promoted the accumulation of phenolic compounds in the leaves of 'Levistro' lettuce plants.

The challenge of composite graft: the use of fluorescent light energy to improve engraftment

Composite graft is a useful tool for the reconstruction of specific facial aesthetic subunits with a single surgical stage. This technique, when successful, gives optimal results in the reconstruction of small defects of nose, ear, eyelid and lips. The aim of this work is to optimize the attachment of composite grafts in the reconstruction of small complex facial defects by combining it with Fluorescent Light Energy (FLE) during the healing process of the graft. The beneficial effects of photobiomodulation (PBM) on wound healing might be attributed to anti-inflammatory signaling, cell proliferation, protein synthesis, and decreased bacterial infection. We previously experienced rewarding achievements using Photonic energy in the treatment of burns, non-healing wounds and pathological scars. Therefore, we chose to exploit the potential of bioluminescent energy to maximize aesthetical and functional results, enhancing the formation of new vascular connections and modulating both inflammatory and scarring processes. From the 2nd postoperative day, the patients were locally treated with 5 FLE sessions every (48/72 h) 2 or 3 days. We evaluated results in terms of time for engraftment, quality of the scarring, infective complications and morbidity of the donor site. Graft survival is subject to many factors, both local and systemic. To overcome these issues, various methods have been studied and described. We here report the successful reconstruction of full-thickness defects of the free margin of the nasal alar rim and the central portion of the inferior lip with a composite graft. These results were highly encouraging if compared with the literature. By analyzing our small cohort, we demonstrated how new technologies may push this traditional reconstructive procedure beyond their old boundaries: overcoming an increased size demand or a potential infective wound environment.

Harnessing Solar Energy for Sustainable Urban Street Lighting

Public street lighting plays an important role in enhancing safety and comfort in urban areas. However, the use of conventional energy for public street lighting significantly contributes to greenhouse gas emissions. This research aims to study the optimization of solar energy usage in public street lighting systems to reduce urban emissions. The methods used include energy efficiency analysis, case studies of solar energy-based public street lighting implementation, and environmental impact evaluation. The results of the study show that the application of solar energy technology in public street lighting can increase energy efficiency by up to 30% and reduce CO2 emissions by 25% compared to conventional systems. In the case study of public street lighting in the city of Binjai, the reduction in carbon emissions reached 99.96%. Additionally, this study also identifies key factors affecting the success of implementation, such as technical design, initial costs, and government policy support. Therefore, optimizing solar energy-based public street lighting not only has the potential to reduce negative environmental impacts but also supports sustainable urban development.

Does the Daily Light Integral Influence the Sowing Density of Tomato Plug Seedlings in a Controlled Environment?

To achieve high-density tomato seedlings in a plant factory with artificial lighting, tomatoes (Solanum lycopersicum Mill. cv. “Zhongza NO.9”) were used as the experimental material. This study expected to analyze the effects of light intensity (150, 200, 250, and 300 μmol·m−2·s−1) and light time (12 and 14 h), as well as daily light integral (DLI, 10.80, 12.60, and 12.96 mol·m−2·d−1) and sowing density (50, 72, and 105 holes per tray), on seedling quality. The results indicated that biomass accumulation, seedling quality, and energy use efficiency of seedlings significantly improved with an increase in DLI. At a DLI of 12.96 mol·m−2·d−1, seedlings sown at a density of 72 holes per tray exhibited comparable growth characteristics and biomass accumulation to those sown at 50 holes per tray. However, under lower DLIs, seedlings at 50 holes per tray displayed superior growth morphology and seedling quality compared to those at 72 holes per tray. This indicates that increasing the DLI can partially mitigate the negative effects of higher sowing density on seedling quality. Light use efficiency (LUE) and energy use efficiency (EUE) were not significantly different between seedlings at 72 and 105 holes per tray but were higher than those at 50 holes per tray. Therefore, optimizing parameters such as DLI and sowing density can effectively enhance the seedling quality, spatial use efficiency, and light use efficiency in industrial seedling production. Based on the results of this study, a DLI of 12.96 mol·m−2·d−1 (achieved with a light intensity of 300 μmol·m−2·s−1 and a light time of 12 h) and sowing density of 72 holes per tray are recommended for cultivating high-quality tomato seedlings while reducing energy consumption.

Soil physico-chemical properties and yield response of cucumber (Cucumis sativus L.) To 2,4-Epibrasinolide under water stress

Dry season production of cucumber is often limited by water availability. Here, we explored the pleiotropic role of 2,4-epibrassinolide (BR) in ameliorating water stress based on changes in soil physico-chemical properties and fruit yield of cucumber under water stressed-conditions. The effects of four water stress levels-WL0, [No stress/control: 860 mL (100% daily irrigation)], WL1 [640 mL (75% daily irrigation)], WL2 [430 mL (50% daily irrigation)] and WL3 = [210 mL (25% daily irrigation)] in factorial combination with foliarly-applied two BR levels [with (BR1= 150 and 250 mL) and without (BR0= 0 mL)] were studied. The soil hydraulic conductivity (Ks) decreased substantially under the water-stressed condition. Soil pH, total nitrogen, available phosphorus, exchangeable bases, effective cation exchange capacity and base saturation were adversely (p ≤ 0.05) affected by water stress, but the exchangeable acidity (EA) was little changed. Water-stressed soil treated with BR showed a significant reduction in EA, increased Ks and nutrient availability. Although dry matter, biological yield, moisture content of the leaves and fruit yield were severely reduced by water stress, treatment with BR increased these by about 89, 27, 41 and 95%, respectively. Light interception was considerably improved under BR treatment as evidenced from the photosynthetically active radiation which increased by 42%. Over all, the increased fruit yield was a result of reduced soil acidity, increased nutrient availability and better use of light energy. Foliar application with BR could sustain growth and fruit yield of cucumber up to 50% of daily irrigation requirement.

Current Advances in Agriculture, Environment, and Chemistry with Technological Applications

Soil contaminated with heavy metals has a negative impact on plant development and survival. On the other hand, plants have developed intricate physiological mechanisms to resist these kinds of environmental stimuli. Anthropogenic sources of emissions are the many industrial point sources, including transporters, smelters and foundries, present and former mining sites, and combustion byproducts. Mercury is released via the degassing of the earth's crust, whereas lead is emitted during its mining and smelting operations, from automotive exhausts by burning petroleum fuels coated with tetraethyl lead antiknock, and from old lead paints. The process of refining zinc releases cadmium as a byproduct and occasionally lead. Emissions are generally released during the mining and processing of metals. Stress from heavy metals affects plants absorb nutrients through interactions with other essential elements. Chromium restricts the quantity of nutrients the soil may absorb by forming insoluble compounds. An intriguing method for managing plastic waste, particularly micro/nano plastics, is photocatalysis. Through the use of suitable light energy, nanostructured semiconductors are excited, producing exciton pairs that react with surrounding water or moisture to produce highly reactive species like superoxide’s and hydroxyl radicals that can effectively oxidize organic species, including polymers. Climate variability affects the sustainability of human and environmental health together with other man-made and natural stresses.

Far-red radiation management for lettuce growth: Physiological and morphological features leading to energy optimization in vertical farming

Recently, far-red wavelengths (FR, 700–750 nm) have been largely investigated in indoor cultivation systems due to their morphological effects on plants (e.g., leaf expansion and stem elongation), resulting also in increasing yield. This work investigated the effect of substituting part of the red (R) and blue (B) radiation with far-red radiation, while keeping constant the photon flux density, in the light spectrum for lettuce grown in a vertical farm. Lettuce (Lactuca sativa var. Canasta) plants were transplanted and grown in an ebb-and-flow system for 29 days. During the cycle, plants were subjected to five different light treatments: a control treatment consisting of an optimized R and B spectrum (ratio of 3; RB3) with a photosynthetic photon flux density of 200 µmol m−2 s−1, and four treatments in which R and B were partially replaced by 10, 30, 50 and 70 µmol m−2 s−1 of FR light, resulting in an increasing FR fraction. Biomass production and most of the morphological parameters were affected from 15 days after transplanting (DAT), while stomatal conductance from 22 DAT. Leaf greenness and specific leaf area values were influenced by the FR radiation starting from 8 DAT. At 29 DAT, substitution of an amount of R and B photons equal to 30 (RB3–30) or 50 (RB3–50) µmol m−2 s−1 with the same amount of FR radiation resulted in increased leaf biomass in both fresh (+49 and +47%, respectively) and dry weight (+45 and +42%, respectively). With RB3–30, the increase was due to leaf area expansion (+103%), whereas stomatal conductance (gs) and quantum efficiency of photosystem II (ΦPSII) did not change compared with the spectrum with only R and B. With RB3–50, gs and ΦPSII decreased compared with RB3 (-27 and -6%, respectively), but the greater biomass accumulation was supported by the greater leaf expansion (+119 %). The adoption of RB3–30 and RB3–50 also promoted light use efficiency (+45 and +42 %, respectively), lighting energy use efficiency (+48 and +53 %, respectively) and therefore the overall energy performance of the system. The adoption of RB3–30 and RB3–50 is a valid strategy to increase yield for lettuce production, but further studies, also in relation to blue radiation intensity, are needed to avoid the negative effect on leaf pigmentation.

Improvement of Climate Resource Utilization in the Southwestern Hilly Region through the Construction of a New Multi-Maturing Cropping System

The construction of an appropriate cropping pattern is crucial for the improvement of regional agricultural economic efficiency and sustainable development. Despite previous efforts, there remains a gap in optimizing cropping patterns that fully leverage climate resources to enhance production efficiency. This study addresses this gap by systematically comparing the differences in climate resource allocation, production efficiency and crop response among models by constructing four new triple-maturing cropping models at typical ecological sites in the hilly areas of southwest China. To solve the above problems, we constructed eight cropping patterns and classified them to three as follows: the Traditional Double Cropping System, the Traditional Triple Cropping System, the Novel Triple Cropping System. The results showed that the new multi-maturing planting pattern was significantly better than the traditional two-maturing netting pattern and the traditional three-maturing planting pattern in terms of light, temperature and water productivity. Compared with the traditional two-maturity net cropping model and the traditional three-maturity cropping model, the new cropping model increased light energy productivity by 97.88% and 50.00%, respectively; light energy use by an average of 0.48% and 0.31%; cumulative temperature productivity by an average of 84.70% and 49.14%; and rainfall productivity by an average of 101.04% and 49.61%. An assessment of the light, temperature and water meteorological resource use efficiency of the different treatments showed that the resource use efficiency of the new multi-maturing planting pattern was on average 111.58% and 74.78% higher than that of the traditional two-maturing net planting pattern and the traditional three-maturing planting pattern, with the T6 pattern having the highest resource use efficiency. The new multi-ripening cropping pattern has demonstrated production stability in response to changes in light, temperature and water resources, better adapting to weekly climate changes, stabilizing yields and improving efficiency. In summary, the results of this study can provide a theoretical basis for optimizing cropping patterns and promoting the use of climate resources in agriculture and sustainable development. Future research should focus on further refining these models, exploring their adaptability to various climatic conditions, and evaluating their long-term economic and environmental impacts.

Simulation-Based Evaluation of the Impact of an Electrochromic Glazing on the Energy Use and Indoor Comfort of an Office Room

Electrochromic glazing alters its optical properties in the absence/presence of an electrical charge, varying from clear to dark to control daylighting and solar heat gains. This study aims to evaluate the impact of an electrochromic glazing, with indoor glare or temperature control, on the energy performance and thermal and visual comfort of an office room under three European climates, using a calibrated simulation model. The novelty of the paper lies in its combined performance assessment, using different standards and metrics. The results showed reduced climatization energy requirements with temperature control, but significantly increased artificial lighting energy use. Glare control achieved useful illuminance levels during 74–80% of working hours. Concerning temperature control, working hours within thermal comfort increased (21–43%) under a free-float regime. Moreover, the performance of this glazing was compared to that of a clear glazing with/without a reflective film and a thermochromic glazing for different solar orientations. The electrochromic glazing with glare control showed the highest energy savings (14–36%) for a western orientation, and the lowest negative impact on daylighting for a northern orientation. The best glare reduction was achieved with the reflective film. Considering the free-float regime, the electrochromic glazing, with temperature control, showed the highest increase in working hours within thermal comfort (6–9%) for a western orientation.

Multi-step FRET systems based on discrete supramolecular assemblies.

Fluorescence resonance energy transfer (FRET) from the excited state of the donor to the ground state of the acceptor is one of the most important fluorescence mechanisms and has wide applications in light-harvesting systems, light-mediated therapy, bioimaging, optoelectronic devices, and information security fields. The phenomenon of sequential energy transfer in natural photosynthetic systems provides great inspiration for scientists to make full use of light energy. In recent years, discrete supramolecular assemblies (DSAs) have been successively constructed to incorporate donor and multiple acceptors, and to achieve multi-step FRET between them. This perspective describes recent advances in the fabrication and application of DSAs with multi-step FRET. These DSAs are categorized based on the non-covalent scaffolds, such as amphiphilic nanoparticles, host-guest assemblies, metal-coordination scaffolds, and biomolecular scaffolds. This perspective will also outline opportunities and future challenges in this research area.

Roles of stakeholders for adopting sustainable design in buildings

Buildings account for the highest carbon dioxide emissions during their operation stage, primarily due to high energy use for heating, cooling, and lighting, which in turn contribute to global warming and climate change. Such impact can be considerably reduced through crafting sustainable design (SusD) in buildings. So, availability of relevant information, professional guidance to clients, and appropriate decision-making are crucial. A study summarized the findings from a questionnaire survey conducted in Brunei with 122 responses. The results revealed that architects, consultants, and government are more important stakeholders to assist with SusD adoption, while clients and developers are important stakeholders in decision-making. The results appreciate the roles of clients and architects to a higher degree, despite a comparatively higher number of private projects in Brunei with relatively more influence of contractors. This was interpreted as having a good degree of awareness of the survey participants towards the role of SusD and who actually can better contribute to SusD adoption. However, the outcome also revealed inconsistent perception among the respondents, both within and between different groups based on their affiliations and nature of job. This inconsistency implies the need for appropriate training or education to enhance awareness of SusD, make pertinent information available, and develop appropriate skills.

Topological insulator Bi2Te3 and graphene oxide synergistically enhance the photothermal effect and photocatalytic hydrogen evolution activity

Photothermal co-catalysis with the partial conversion of solar energy to thermal energy has the potential to overcome the current bottleneck of realizing efficient photocatalytic hydrogen production with zero artificial energy consumption. However, it is still challenging to design highly efficient photocatalysts that can make use of light and thermal energy synergistically. In this work, we successfully improved the photothermal effect and visible-light-catalyzed hydrogen evolution performance by constructing a novel heterojunction based on the topological insulator Bi2Te3 and graphene oxide (GO) synergistically modified with Zn0.67Cd0.33S. The photocatalytic hydrogen evolution rate of the 1.1 wt% Bi2Te3@0.05% GO@Zn0.67Cd0.33S heterojunctions reached 11.52 mmol/h/g (Apparent Quantum Yield of 21.7%), which was 12.9 times higher than that of pure Zn0.67Cd0.33S. Furthermore, the hydrogen production rate reached 71.79 mmol/h/g without cooling. The improved photocatalytic activity originated from the synergistic enhancement of visible-light absorption and the systematic enhancement of the photothermal effect by the Bi2Te3 and GO. In addition, the high electrical conductivity of Bi2Te3 and the high proton conductivity of GO not only increased the electron transfer rate but also synergistically mediated the acceleration of the hydrogen generation reaction. A strong built-in electric field is formed between Bi2Te3 and Zn0.67Cd0.33S, which greatly facilitates the efficient separation of photogenerated carriers. The obtained results illustrate a promising strategy for the development of efficient new photothermal catalysts.

Optimizing Energy Efficiency in Indian Buildings: A Comprehensive Analysis of Current Norms and Proposed Guidelines for Strategic Placement and Orientation

The concept of energy-efficient buildings is increasingly critical in today's world, where energy conservation and environmental sustainability are paramount. Energy-efficient buildings are designed to minimize the use of energy for heating, cooling, lighting, and other operations without compromising on comfort or utility. This approach not only helps in reducing the overall energy demand but also contributes significantly to mitigating climate change by lowering carbon emissions. This research focuses on optimizing energy efficiency in residential buildings, recognizing the crucial role of the residential sector in overall energy consumption. The study investigates innovative approaches, technologies, and design strategies to enhance energy performance while ensuring occupant comfort and cost-effectiveness. Key Word: Energy efficient, Glazing system, Solar radiation, Energy consumption, Green practice.

Variability of Primary Productivity as an Initial Link in Carbon Flux Under the Influence of Hydrological Conditions in the Baltic Sea

Investigating variability in phytoplankton primary productivity as a key component of the “biological pump” is critical to quantifying flux in the marine environment. We hypothesized that under certain hydrological conditions, changes in phytoplankton productivity are greater with changes in photosynthetic efficiency (the ratio of primary production (P P ) to the rate of electron transport in the phytoplankton photosystem, P P /ETR) than with changes in chlorophyll content. This study showed that increase of P P during sharp changes in hydrological parameters in the temporary frontal South-East Baltic (SEB) is achieved by increasing the efficiency of photosynthesis, i.e., the degree of use of light energy captured by chlorophyll a (Chl a). In the Gulf of Finland (GF), an increase in P P followed an increase in salinity from the Neva mouth to the sea and controls chlorophyll contents with low variability in photosynthetic efficiency. For SEB and GF, measurements of parameters of phytoplankton productivity and chlorophyll a content in late autumn (November) are carried out. The first stage of carbon flow (in biological pump), expressed in terms of primary production, was higher in the SEB than in the GF

Coping with darkness: residents’ experience of reduced outdoor lighting in neighbourhoods

Despite ongoing replacement of old lighting installations with new energy-efficient light emitting diodes, the energy crisis has led to the implementation of strategies for reducing energy use for public outdoor lighting in neighbourhood environments. This would save money and reduce light pollution; however, the situations should be evaluated from the residents’ perspective. This paper presents a pilot study, which aimed to explore how residents experience and respond to reduced outdoor lighting in their neighbourhoods during dark hours, by applying the adapted Human-Environment Interaction model to understand the relation between outdoor lighting quality, neighbourhood quality and local independent mobility from the residents’ perspective. The pilot study was based on a short questionnaire (N =76, 29 males, 47 females, Mage = 66.66 years) and telephone or online interviews (N = 13, 5 males, 8 females, Mage = 68.08 years) with the residents living in the neighbourhood areas, in Southern Sweden, where strategies were employed for reducing the use of public outdoor lighting. Data were collected between February and March 2023. Overall, the results affirmed the important role of outdoor lighting quality in residents’ experience of neighbourhood environments and local independent mobility (i.e. the ability of residents to walk or move around on their own in their neighbourhood area), whereas the effect of reduced outdoor lighting was rather insignificant. The interviews further showed different experiences of the reduced outdoor lighting and how the residents coped with the lighting conditions by using solutions (i.e. headlamps, flashlights, bike lamps and reflectors), and that high-level perceived safety from crime in the neighbourhoods was found to play an important role in local independent mobility during dark hours. The adapted conceptual model allowed for the evaluation of outdoor lighting conditions considering both internal and external factors from the residents’ perspective, and could provide a basis for discussion about potential changes in public outdoor lighting.

Toxicological effects and mechanisms of lithium on growth, photosynthesis and antioxidant system in the freshwater microalga Chromochloris zofingiensis

The growing prevalence of lithium (Li) batteries has drawn public attention to Li as an emerging pollutant. The present study investigates the toxicity of Li+ on Chromochloris zofingiensis, examining physiological, biochemical and omics aspects. Results reveal hormesis effects of Li+ on C. zofingiensis growth. At Li+ concentrations below 5 mg L−1, Li+ can enhance chlorophyll content, mitochondrial activity, and antioxidant capacity, leading to increased dry cell weight and cell number. Conversely, when it exceeded 10 mg L−1, Li+ can reduce chlorophyll content, induce oxidative stress, and disrupt chloroplast and mitochondria structure and function, ultimately impeding cell growth. In addition, under 50 mg L−1 Li+ stress, microalgae optimize absorbed light energy use (increasing Fv/Fm and E TR ) and respond to stress by up-regulating genes in starch and lipid biosynthesis pathways, promoting the accumulation of storage components. Weighted gene co-expression network analysis indicates that peptidylprolyl cis/trans isomerase, GTPase and L-ascorbate oxidase might be the key regulators in response to Li+ stress. This research marks the toxic effects and molecular mechanisms of Li+ on freshwater microalga, which would improve our understanding of Li’s toxicology and contributing to the establishment of Li pollution standards.