Search Results (365)

Emission reduction remains the foundation of air-pollution control, yet the relationship between reduced emissions and improved ambient air quality is frequently non-proportional. This mismatch is not an exception to atmospheric behavior but a consequence of coupled chemical, meteorological, transport, and removal processes. Here, we critically synthesize global evidence for nonlinear air-quality responses to emission controls, with particular attention to fine particulate matter (PM_2.5) and ozone (O₃). We distinguish five response forms that are directly relevant to policy: near-linear, sublinear, superlinear, threshold, and sign-reversal behavior. Ozone provides the clearest example because the response to nitrogen oxides (NOx) and volatile organic compounds (VOCs) depends on the prevailing photochemical regime and can change as emissions decline. PM_2.5 responses are likewise nonlinear because precursor controls alter atmospheric oxidation capacity, gas-particle partitioning, aerosol water, and interactions among nitrate, sulfate, ammonium, and secondary organic aerosol. Aerosol reductions can further modify photolysis and boundary-layer processes, linking PM_2.5 control to O₃ production. Regional transport and background concentrations attenuate or redistribute the benefits of local controls, while meteorological variability changes both chemical sensitivity and the realized concentration response. These mechanisms imply that sustainable air-quality management cannot be evaluated solely by tonnes of emissions avoided. Instead, policy performance should be assessed along the complete pathway from emission reduction to ambient concentration, exposure, health, climate, ecosystem, equity, and economic outcomes. We propose a sustainability-oriented framework in which control strategies are evaluated for atmospheric effectiveness, multipollutant coherence, spatial equity, climate compatibility, and robustness across changing chemical and meteorological regimes. The evidence supports adaptive, coordinated, and regionally integrated control portfolios rather than fixed single-pollutant reduction ratios. Full article

The degradation of bromothymol blue (BTB) in aqueous solution was investigated through individual and sequential photochemical and enzymatic treatments. Photodegradation experiments were performed under UVC, UVB, UVA and visible irradiation at different pH values and atmosphere conditions, while enzymatic degradation was evaluated using Laccase from Trametes versicolor under varying pH, temperature and enzyme concentration. Kinetic analyses were performed in all cases. BTB degradation was strongly dependent on irradiation wavelength and pH. The highest photodegradation rates were obtained under UVC irradiation, particularly in alkaline medium. Additionally, our results suggest that BTB photolysis mainly proceeds through a unimolecular pathway. On the other hand, enzymatic degradation was favored at acidic pH, elevated temperature, and high amount of laccase, with optimal performance observed at pH 5 and 40 °C. Sequential treatments combining photochemical and enzymatic processes improved the overall removal efficiency, reaching degradation values above 70% regardless of the treatments order. Ecotoxicological evaluation using the Vibrio fischeri bioluminescence inhibition assay revealed a significant reduction in toxicity after all treatments, particularly those involving UVC irradiation. These results demonstrate the complementary nature of both processes and highlight the potential of combined photochemical–enzymatic treatments for the remediation of dye-contaminated waters. Full article

Trehalose-6-phosphate (T6P) is a key signalling metabolite that integrates carbon availability with development and stress responses in plants. T6P levels are controlled by trehalose phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) enzymes; however, while TPS enzymes have been studied extensively, the physiological functions of individual TPPs remain incompletely understood. Here, we investigated the role of TPPI in Arabidopsis using loss-of-function tppi mutants, a complemented line (tppi+35S::TPPI), and TPPI-overexpressing (TPPI-OEX) plants. The tppi mutant exhibited delayed flowering accompanied by reduced expression of CO, FT, and SPL3, while complementation restored wild-type (WT) flowering time. TPPI-OEX plants displayed an intermediate flowering phenotype with moderate reductions in CO and FT expression. Under nitrogen starvation, tppi plants showed enhanced anthocyanin accumulation, altered nitrate reductase regulation, characterised by lower total enzyme activity but a higher activation state, and enhanced expression of nitrate assimilation and uptake genes (NIA1, NIA2, NRT1.1, and NRT2.1). TPPI deficiency also altered photosynthetic performance, with enhanced photosystem I (PSI) acceptor-side limitation, increased non-photochemical quenching (NPQ), and a tendency toward reduced photosystem II (PSII) electron transport, indicating altered photosynthetic electron transport and energy dissipation. Taken together, these results indicate that TPPI contributes to the regulation of flowering time, nitrogen responses, and photosynthetic performance, suggesting broader effects of TPPI on plant developmental and physiological processes. Full article

Novel and efficient total syntheses of the nonsteroidal anti-inflammatory drugs Pelubiprofen and Loxoprofen via a photo-Favorskii rearrangement are reported herein. The key photochemical transformation was optimized under both batch and continuous-flow conditions using a suitably functionalized chloro-phenylpropan-1-one derivative, affording the target 2-arylpropionic acid in excellent yield. Implementation under continuous-flow conditions increased process productivity and enabled gram-scale operation. Aerobic oxidation of the benzylic position to the corresponding aldehyde, followed by Claisen–Schmidt condensation with cyclohexanone, afforded Pelubiprofen in 35% overall yield. Alternatively, condensation with cyclopentanone afforded the corresponding α,β-unsaturated enone intermediate, whose selective reduction under flow conditions enabled access to Loxoprofen in 28% overall yield. The versatility of the methodology was further demonstrated through the synthesis of Carprofen, highlighting the broader applicability of the photo-Favorskii rearrangement to the synthesis of APIs through previously unreported synthetic routes. Full article

Photo-induced reactions, also known as photochemical reactions, are chemical processes that are initiated or driven by the absorption of light energy. Photo-induced reactions have been applied in a variety of fields from organic synthesis to polymer curation. One such application of much current interest is additive manufacturing (AM)—a technique used within a variety of fields to produce intricately shaped components. Currently, additive manufacturing is utilized within the solar, medicine, electronic, and nuclear application industries, making it a diverse and expansive system of production. Present reviewed AM production methods include laser powder bed fusion (L-PBF), stereolithography (SLA), direct energy deposition (DED), and selective laser sintering (SLS). However, the literature points to the need for expansion of feedstock capabilities as the horizon broadens to extreme environments like nuclear reactors, a solution which might be found in photolytic reaction synthesis. This review examines photo-induced synthesis most applicable to additive manufacturing, focusing on four key reaction types: oxidation–reduction, combustion, decomposition and polymerization. Past and present applications, future challenges, and emerging opportunities regarding photolytic reaction synthesis are analyzed. This assessment provides insights into the current state and future potential of these reactions in advancing additive manufacturing technologies. Full article

Anthropogenic air pollution represents a significant threat to both environmental and human health, with nitrogen oxides (NO_x) playing a substantial role in the formation of photochemical smog, acid rain, eutrophication, and respiratory diseases. In Bangladesh, NO_x emissions primarily originate from combustion sources such as road transportation, power generation, and industrial activities, while natural sources include lightning, wildfires, and soil emissions. Furthermore, ammonia emissions from fertilizers and livestock exacerbate air quality issues in both urban and rural settings. Despite the acknowledgment of vehicular and industrial contributions, comprehensive and systematic assessments of NO₂ trends across the nation remain scarce. This study presents a complementary, side-by-side assessment of ground-based NO₂ measurements from the Department of Environment (DoE) with atmospheric NO₂ retrieved from the Sentinel-5P TROPOMI Level-3 product via Google Earth Engine (GEE). Spatial distribution patterns of both ground-level and atmospheric NO₂ were analyzed using ArcGIS Pro, along with seasonal and interannual trend assessments from 2018 to 2024. Results indicated pronounced spatial and temporal variability in NO₂ concentrations. The highest levels were consistently recorded over Dhaka and surrounding industrial zones, with moderate accumulation in Chattogram. Winter months (December–February) exhibited hazardous concentrations, with a national maximum of 205.21 µg/m³, while monsoon periods recorded the lowest levels overall, as reflected in its seasonal mean (see below). Seasonal averages indicated the highest concentrations in winter (35.03 µg/m³), followed by pre-monsoon (29.16 µg/m³), with monsoon recording the lowest seasonal mean (19.94 µg/m³). Long-term analysis showed the highest national annual mean NO₂ con-centration in 2018 (44.32 µg/m³), decreasing to 14.81 µg/m³ by 2024, with non-monotonic year-to-year fluctuation in the intervening period (2020–2021 data were unavailable). These findings underscore the necessity for stricter emission regulations and targeted mitigation measures. As a policy recommendation, this may include the implementation of NO_x-selective catalytic reduction (SCR) using NH₃ over metal oxide and zeolite catalysts. This study provides evidence-based insights to support cleaner air initiatives and sustainable environmental management strategies in Bangladesh. Full article

The genus Euterpe, which includes açaí palm (Euterpe oleracea) and juçara palm (Euterpe edulis), plays an important socioeconomic and environmental role in Brazil. However, soil and water salinization is a global issue that compromises agricultural productivity by affecting plant physiological and metabolic processes. This study aimed to evaluate the physiological responses of young açaí and juçara plants under salt stress. The experiment was conducted in a randomized complete block design in a 5 × 2 factorial arrangement, consisting of five irrigation water salinity levels (0.1, 1.0, 2.0, 3.0, and 5.0 dS m⁻¹) and two Euterpe species (açaí and juçara), with four replicates. After 104 days of stress exposure, gas exchange, chlorophyll ‘a’ fluorescence, relative chlorophyll index (SPAD), and sodium, chloride, and phenolic compounds were evaluated. Increasing salinity caused linear reductions in the maximum quantum yield and potential photochemical efficiency of PSII, accompanied by an increase in F₀/Fm, indicating impaired PSII photochemical performance and photoinhibition. Stomatal conductance and transpiration also decreased significantly with increasing salinity, with reductions of up to 41.33% and 35.48%, respectively, at the highest salinity level. Salt stress negatively affected the physiological performance of both palm species through stomatal limitation and reduced photosystem II efficiency. However, açaí plants exhibited greater tolerance to salt stress than juçara plants. Full article

The frequency and magnitude of droughts are increasing concurrently with atmospheric CO₂ concentration, with profound consequences for plant carbon assimilation. However, the interactions and the underlying physiological mechanism are still not fully understood. To fill the knowledge gap, we exposed Chinese fir (Cunninghamia lanceolata) saplings to two CO₂ concentrations (400 and 800 ppm, representing ambient and elevated CO₂) and two soil water regimes (70% and 40% field capacity; well-watered and drought-stressed conditions) in a factorial design. Net photosynthetic rate (A_n), chlorophyll fluorescence, photosynthetic pigments, oxidative stress indicators, and antioxidant enzyme activities were measured four times over a 45-day treatment period. Under well-watered conditions, elevated CO₂ significantly increased A_n by 61.5%. However, drought stress substantially reduced A_n by 75.0% under ambient CO₂ and by 75.6% under elevated CO₂, whereas no statistically significant CO₂-induced increase was detected under drought conditions. Furthermore, drought stress caused marked reductions in stomatal conductance, transpiration, chlorophyll content, and photosystem II (PSII)-related parameters, together with increased malondialdehyde, proline, and antioxidant enzyme activities. Variance partitioning analysis suggested that stomatal regulation (SR), photosynthetic capacity (PC), and stress response (STR) jointly explained 71% of the variation in A_n. Structural equation modeling further suggested that drought stress restricted the photosynthetic benefits of elevated CO₂ primarily through stomatal closure, concurrently associated with stress-related declines in pigment stability and photochemical performance. These findings suggest that the carbon sink potential of Chinese fir plantations under future CO₂-enriched climates may be strongly constrained by water deficits. Full article

Background: Infrared (IR) radiation constitutes the dominant component of the energy reaching the Earth’s surface and plays a significant role in the photochemical and thermal processes occurring in the skin. The aim of this study was to evaluate the photoprotective potential of selected cosmetic ingredients—ferulic acid, citrus pectin, and dextran—against IR radiation using the directional hemispheric reflectance (DHR) method in an ex vivo model. Methods: Formulations based on an amphiphilic carrier (Lekobaza) containing various concentrations of the tested substances were developed, and their optical and thermal properties were evaluated. Results: The results showed that the application of all formulations led to a statistically significant reduction in reflectance in the near- and mid-infrared range, indicating an increase in the absorption of radiation energy within the formulation layer. The strongest absorption effect was observed for ferulic acid, which—in addition to its antioxidant properties—exhibits the ability to absorb IR energy and dissipate it as heat. Pectin and dextran formed a water-binding hydrocolloid matrix on the surface, acting as a selective “water filter” for long-wavelength radiation (IR-B and IR-C). At the same time, all the tested systems increased the surface’s thermal emissivity, which promotes more efficient dissipation of absorbed energy through radiative cooling and may support the skin’s natural thermoregulation. Conclusions: The obtained data indicate that protection against IR radiation should not be defined solely as the physical reflection of radiation, but as a complex process of managing the skin’s energy balance, encompassing surface absorption, heat dissipation, and the neutralization of biological effects. The results support the development of hybrid photoprotective systems combining antioxidant and thermoregulatory mechanisms to prevent thermal aging-related changes. Full article

Proper substrate moisture management is essential for producing high-quality seedlings in nurseries. This study aimed to evaluate the morphological and physiological quality of lettuce (Lactuca sativa L.) and tomato (Solanum lycopersicum L.) seedlings subjected to different substrate moisture levels, monitored by weighing lysimetry under protected environment conditions. Four experiments were conducted over two growing seasons (2019 and 2020) using six irrigation treatments corresponding to 80, 70, 60, 50, and 40% of the substrate water-holding capacity, in addition to the conventional irrigation management adopted by the grower (Control). Water consumption, morphological traits, root architecture, gas exchange, chlorophyll fluorescence, and photosynthetic pigments were assessed. Cumulative irrigation water applied ranged from 77 to 92 mm in lettuce and from 91 to 132 mm in tomato. Reducing substrate moisture to 40% negatively affected seedling growth, root development, and physiological performance in both species. In tomato, stomatal conductance decreased by up to 90%, accompanied by a decline in Fv/Fm from 0.78 to 0.70. Both lettuce and tomato tolerated moderate reductions in substrate moisture (60–70% holding capacity) without significant losses in growth or gas exchange performance. However, the highest seedling quality was achieved under the grower-managed Control and the 80% substrate moisture treatment, although the traits contributing to this response differed between species. In lettuce, favorable performance was associated with growth, pigment-related traits, and photochemical efficiency, whereas in tomato superior seedling quality was linked to shoot growth, root development, and gas exchange characteristics. These findings support the use of species-specific irrigation strategies to improve seedling quality in nursery production. Full article

This work aimed to evaluate the combined effects of an antibiotic (erythromycin, ERY) and an herbicide (metolachlor, MET), at environmentally relevant concentrations, on the physiology of the freshwater microalga Raphidocelis subcapitata. For this purpose, firstly, the alga was exposed to each toxic compound to determine the respective effect concentrations after 72 h (72h-EC values). Subsequently, the alga was exposed to mixtures composed of 72h-EC₁₀, 72h-EC₂₅, and 72h-EC₅₀ values of each toxicant, and interaction analysis was conducted using the independent action (IA) model. Overall, the mixtures of ERY and MET inhibited algal growth synergistically. Regarding photosynthetic performance, exposure to the mixtures of toxicants, generally resulted in a reduction of the maximum photochemical efficiency of photosystem II (PSII) (F_v/F_m), the effective photochemical yield of PSII (Φ_PSII), and the electron transport rate (ETR). However, MET antagonizes the negative effects of ERY on photosynthesis, particularly at lower concentrations of the antibiotic (72h-EC₁₀ and 72h-EC₂₅). The exposure to ERY–MET mixtures resulted in an overall increase in photosynthetic pigments (chlorophyll a and carotenoids), likely reflecting a compensatory response by the alga to counterbalance impaired photosynthetic function. Nonetheless, overall pigment analysis indicated an antagonistic interaction between the two toxicants, as the magnitude of this increase was lower than predicted by the IA model. The results presented here provide new insights into the toxicological interactions between ERY and MET in microalgae and contribute to addressing the critical knowledge gap regarding the ecotoxicity of pharmaceutical–herbicide mixtures in aquatic environments. Full article

Background/Objectives: An evaluation of the sensitizing properties of chloroindium(III) phthalocyanine complex (InPc) bearing 4-sulfonylphenoxy groups was performed. Methods: The ability to form singlet oxygen under light exposure was assessed, and the quantum yield Φ_Δ was calculated to be 0.82 ± 0.04. Under ultrasound exposure of the sensitizer (1 MHz, 3 W, 40% duty cycle), significant 1,3-diphenylisobenzofuran decomposition was observed. Results: Moreover, the macrocycle was assigned to be a moderate–high photo- and sonostable sensitizer. Density functional theory studies supported experimental results, suggesting the InPc to be a good photochemical agent. From the global reactivity parameters analysis, it can be suggested that InPc would interact easily with electron-excess species, such as various free radicals, in the solution phase, and should also be able to interact with electrophilic species. Conclusions: Studied InPc revealed high photodynamic antimicrobial activity and reached >4 log₁₀ reduction in microbial growth against methicillin-resistant Staphylococcus aureus, and 4.08 ± 0.29 log₁₀ against Candida albicans resistant to fluconazole (for dosimetry of 100 μM and 50 J/cm²). Interestingly, the photosensitizer studied was inactive against extended-spectrum β-lactamase-producing Escherichia coli. Full article

Water deficit is a major abiotic constraint limiting maize growth and productivity worldwide. Although silicon (Si) is not classified as an essential element, its beneficial effects on numerous crop species are well documented. Silicon has been shown to promote plant growth and enhance tolerance to abiotic stresses, particularly drought stress. Seed priming, a pre-sowing technique known to stimulate early germination processes, has emerged as a promising approach to enhance seedling establishment and stress tolerance in crops. In the present study, silicon-based seed priming was investigated as a strategy to alleviate the adverse effects of water deficit in maize (Zea mays) using two sodium silicate priming-solution concentrations (10 and 20 mM). Maize plants were subjected to six experimental treatments based on seed priming: three under well-watered conditions (no silicon seed priming and seed priming with 10 and 20 mM sodium silicate solutions) and three corresponding treatments combined with irrigation withdrawal for 15 days to induce drought stress. Morphological traits, biomass accumulation, photosynthetic pigment content, plant water status, and PSI- and PSII-related photochemical parameters were evaluated. Drought stress markedly reduced plant growth, biomass production, relative water content, chlorophyll pigment levels, and photosystem photochemical performance, reflecting a strong negative impact of water deficit on most measured parameters. In particular, root and shoot fresh weights decreased by 75% and 71%, respectively, compared with those of well-watered unprimed control plants, indicating a substantial reduction in biomass accumulation under drought conditions. Furthermore, drought conditions impaired photochemical performance and increased non-regulated energy dissipation, indicative of impaired photosynthetic performance. Silicon seed priming mitigated several drought-induced effects in a trait-dependent manner. Under water-deficit conditions, 20 mM Si produced the strongest improvement in root and shoot fresh weights, whereas 10 mM Si showed stronger responses for selected shoot-growth and PSI-related parameters. Both Si treatments improved leaf water status and photosynthetic stability to varying extents. Collectively, these results indicate that sodium silicate seed priming partially improves drought-related responses in maize seedlings under the conditions of this study by sustaining growth performance, preserving plant water status, and maintaining photosynthetic stability under water-deficit conditions. Full article

Waterlogging at the tillering stage, a key early vegetative growth stage, is increasingly limiting wheat productivity worldwide, but the physiological mechanisms underlying genotypic tolerance are not fully understood. To address this, 23 bread wheat (Triticum aestivum L.) genotypes from five germplasm groups were exposed to 14 days of waterlogging at the tillering stage. Morphological traits including leaf (green area, biomass, and senescent biomass proportion) and the elongation rate of the main culm (cm day⁻¹), plant water status (relative water content, RWC), photosynthetic pigment content (SPAD values; total chlorophyll, TChl; total carotenoids, TCar), and photosynthetic performance (maximal photochemical efficiency of photosystem II, F_v/Fm; actual photochemical efficiency of photosystem II, F_v′/F_m′; net photosyntheis, P_n; stomatal conductance to water vapor, g_s), were assessed. Waterlogging induced strong but highly variable responses among genotypes. Sensitive genotypes showed marked reductions in green biomass (up to ~40–60%), TChl content (up to ~80%), TCar (~70%), and photosynthetic performance, including declines in F_v/F_m, F_v′/F_m′, and P_n. In contrast, tolerant genotypes maintained higher photochemical efficiency, P_n, and pigment content, despite stress exposure, underscoring greater functional resilience. Importantly, morphological stability did not consistently translate into functional performance. Several genotypes maintained green leaf area despite pronounced declines in photosynthetic capacity and pigment content, revealing a decoupling between morphological and physiological responses. Multivariate analysis identified an integrated photosynthetic trait axis strongly associated with yield performance under stress, highlighting that tolerance is primarily driven by the capacity to maintain photosynthetic function rather than green biomass alone. Together, these findings emphasize the importance of preserving both physiological functionality and green leaf area to maintain waterlogging tolerance. Integrated physiological markers (e.g., TChl and TCar content, photochemical quenching, leaf gas exchange traits) enable effective early screening and support function-based selection in wheat breeding programs. Full article

Lignin is the most abundant renewable source of aromatic carbon, and yet it remains a mostly underutilized byproduct of the biorefinery and paper industries. Factors such as complexity and a heterogeneous structure make lignin recalcitrant to conventional valorization, the utility of which often requires harsh conditions and expensive catalysts. Electrochemical conversion has emerged as a highly promising, sustainable alternative due to the use of electricity produced by renewable sources to drive depolymerization under mild, ambient conditions. This review summarizes recent progress in this field and provides a comprehensive overview of the primary electrochemical pathways used to promote the valorization of lignin. Herein, we critically examine oxidative strategies that include both direct electrooxidation at the anode surface and indirect oxidation using redox mediators, and provide details of the key challenges of electrode deactivation and product overoxidation. We then discuss reductive strategies with a focus on electrocatalytic hydrogenolysis for C-O bond cleavage. Furthermore, we explore advanced integrated systems that combine electrochemistry with microbial, enzymatic, and photochemical processes to enhance selectivity and efficiency. Finally, this review addresses persistent challenges and offers future perspectives and suggests opportunities with an emphasis on the critical need for innovations in electrocatalyst design, green electrolytes, and integrated reactor engineering to unlock the full potential of lignin as a renewable feedstock for a circular carbon economy. Full article