Search Results (661)

Addressing the growing threat of climate change requires urgent and sustainable solutions for managing carbon dioxide (CO₂) emissions. This review investigates the latest advancements in technologies for capturing and converting CO₂, with a focus on approaches that prioritize energy efficiency, environmental compatibility, and economic viability. Emerging strategies in CO₂ capture are discussed, with attention to low-carbon-intensity materials and scalable designs. In parallel, innovative CO₂ conversion pathways, such as thermocatalytic, electrocatalytic, and photochemical processes, are evaluated for their potential to transform CO₂ into valuable chemicals and fuels. A growing body of research now focuses on integrating capture and conversion into unified systems, eliminating energy-intensive intermediate steps like compression and transportation. These integrated carbon capture and conversion/utilization (ICCC/ICCU) technologies have gained significant attention as promising strategies for sustainable carbon management. By bridging the gap between CO₂ separation and reuse, these sustainable technologies are poised to play a transformative role in the transition to a low-carbon future. Full article

Synthesizing natural substances has always been a significant challenge for organic chemists. The key to a successful total synthesis lies in utilizing reactions that generate molecular complexity with high stereocontrol. Photochemical reactions offer immense potential in this regard, though their complex mechanisms require careful mastery. This review explores recent examples from the literature where light-mediated reactions are crucial, often irreplaceable by thermal alternatives. The manuscript is organized by different photochemical processes, each introduced with relevant background. This review does not offer a complete analysis of all recent light-assisted syntheses; rather, it offers a glimpse into the growing trend of using photo-driven transformations to address significant synthetic challenges. Full article

High-Intensity Laser Therapy (HILT) represents a mechanistic subset of High-Power Laser Therapy (HPLT), distinguished by the addition of a photoacoustic component to established photochemical and photothermal effects. High-peak (kW), short-pulse emission generates pressure waves exceeding 10 kPa in water (27 °C) and approximately 100 kPa in vivo, levels that are compatible with the activation of mechanotransductive processes relevant to cellular differentiation. These pressure waves propagate several centimeters into biological tissues, extending beyond the optical penetration depth of light. We introduce Pulse Energy Dose (PED), a physically grounded and clinically oriented dose metric, to determine whether a laser system meets the photoacoustic threshold while remaining within the thermoelastic regime. Only systems combining kilowatt-range peak power, microsecond pulses, high pulse energy, and very low duty cycles (<1%) consistently induce pressure waves within the therapeutic thermoelastic regime. PED was validated against the Margheri equation, showing a strong linear correlation with calculated pressure wave amplitude (Pearson r > 0.9, p < 0.0001). Based on these results, we define operational bounds that identify high-power laser systems capable of producing reproducible photoacoustic effects within thermoelastic conditions. This framework shifts classification from average power to mechanism of action, providing guidance for safe parameter selection and supporting a mechanism-based clinical use of high-power lasers, particularly in musculoskeletal disorders, cartilage regeneration, bone healing, and deep-tissue repair. Full article

Global warming is increasingly constraining plant productivity by altering the photosynthetic energy balance and leaf thermoregulation. Under high light and elevated temperatures, absorption of energy in excess (AEE) by photosystem II disrupts photosynthetic electron transport, oxygen evolution, and CO₂ assimilation, often accompanied by reduced foliar transpiration. These conditions promote photoinhibition, as reflected by a decrease in maximal photosynthetic efficiency (Fv/Fm), an increase in non-photochemical quenching (NPQ), and photooxidative stress associated with enhanced reactive oxygen species (ROS) production. In addition to environmental heat stress, AEE influences foliar temperature through internal energy partitioning, including regulated dissipation of AEE as heat and changes in transpirational cooling. The relative contributions of NPQ, photochemistry, and transpiration to leaf temperature regulation are strongly context dependent and vary with light intensity, temperature changes, and water availability. Under global warming, rising background temperatures and increased vapor pressure deficit may constrain transpirational cooling and alter the balance between non-photochemical and photochemical energy dissipation and usage, respectively. In this review, we synthesize current knowledge on AEE handling, photoinhibition, NPQ and other quenching processes, and on transpiration cooling, and discuss a conceptual framework in which sustained imbalance among these processes under global warming conditions could amplify foliar heat stress and increase the risk of cellular damage. Rather than proposing new physiological mechanisms, this work integrates existing evidence across molecular, leaf, and ecosystem scales to highlight potential feedbacks relevant to plant performance under future climate prediction scenarios. Full article

This study investigates the synthesis and photochemical behavior of a series of (E)-1-aryl-1,3-butadienes with different aromatic substituents. Despite their simple structure and straightforward preparation, detailed studies of their photochemical properties, especially UV light-induced (E) to (Z) isomerization, are scarce. Our results demonstrate that these compounds can efficiently undergo photo-triggered geometric changes, highlighting their potential as functional units in photochemical applications. The findings underline the significance of extended conjugation in managing excited-state processes, providing new insights into the dynamics of photoinduced transformations in conjugated diene systems. Additional computational analyses show how geometric modifications influence conformational energies in the synthesized compounds. Overall, these results improve understanding of structure–reactivity relationships and lay the foundation for designing photoresponsive materials based on (E) and (Z)-1-aryl-1,3-butadiene frameworks, with promising applications in photochemistry and materials science. Full article

Given the deteriorating situation of ambient ozone (O₃) pollution in some areas of China, understanding the mechanisms driving O₃ formation is essential for formulating effective control measures. This study examines O₃ formation mechanisms and RO_x (OH, HO_2, and RO₂) radical cycling driven by photochemical processes in Bozhou, located at the junction of Jiangsu–Anhui–Shandong–Henan (JASH), a region heavily affected by O₃ pollution, by applying a zero-dimensional box model (Framework for 0-Dimensional Atmospheric Modeling, F0AM) coupled with the Master Chemical Mechanism (MCM v3.3.1) and Positive Matrix Factorization (PMF 5.0) to characterize O₃ pollution, identify volatile organic compound (VOC) sources, and quantify radical budgets during pollution episodes. The results show that O₃ episodes in Bozhou mainly occurred in June under conditions of high temperature and low wind speed. Oxygenated volatile organic compounds (OVOCs), alkanes, and halocarbons were the dominant VOCs groups. The CH₃O₂ + NO reaction accounted for 24.3% of O₃ production, while photolysis contributed 68.7% of its removal. Elevated VOCs concentrations in Bozhou were largely maintained by anthropogenic sources such as vehicle exhaust, solvent utilization, and gasoline evaporation, which collectively enhanced O₃ production. The findings indicate that O₃ formation in the region is primarily regulated by NO_x availability. Therefore, emission reductions targeting NO_x, along with selective control of OVOCs and alkenes, would be the most effective strategies for lowering O₃ levels. Model simulations further highlight Bozhou’s strong atmospheric oxidation capacity, with OVOC photolysis identified as the dominant contributor to RO_x generation, accounting for 33% of the total. Diurnal patterns were evident: NO_x-related reactions dominated radical sinks in the morning, while HO₂ + RO₂ reactions accounted for 28.5% in the afternoon. By clarifying the mechanisms of O₃ formation in Bozhou, this study provides a scientific basis for designing ozone control strategies across the JASH junction region. In addition, ethanol was not directly measured in this study; given its potential to generate acetaldehyde and affect local O₃ formation, its possible contribution introduces additional uncertainty that warrants further investigation. Full article

Triclosan (TCS) is a widely used antimicrobial agent found in personal care products and household cleaners. While valued since the 1960s for its ability to inhibit bacterial fatty acid synthesis, its environmental persistence, ecotoxicity, and bioaccumulative potential have raised significant global concern. The increased use of disinfectants during the COVID-19 pandemic has further exacerbated its prevalence as an aquatic pollutant. In the environment, TCS is distributed through water bodies and sediments, undergoing processes such as biodegradation and photochemical degradation. Its bioaccumulation poses a substantial threat to aquatic organisms, particularly fish. A growing body of research indicates that TCS acts as an endocrine disruptor and developmental toxicant, with documented adverse effects encompassing impaired embryonic and larval development, skeletal malformations, and induction of oxidative stress, mitochondrial dysfunction, DNA damage, and inflammatory responses. Furthermore, TCS exposure is linked to reproductive toxicity, including altered sex hormone levels and diminished reproductive capacity. This review consolidates current knowledge on the chemical properties, environmental fate, biodegradation pathways, and ecotoxicological impacts of TCS, with a specific emphasis on its multifaceted health risks to fish. The synthesis aims to provide a foundation for future research, inform environmental risk assessments, and support the development of evidence-based regulatory measures. Full article

Phytochrome-interacting factors (PIFs) are key transcriptional regulators of phytochrome signalling that coordinate photomorphogenesis and photosynthesis under different environmental conditions. PIFs play an important role in this regulation and act mainly as negative regulators of photomorphogenesis, but under high-intensity light (HIL), their functions can also include adaptive roles. We investigated the contribution of individual PIFs to the adaptation of the photosynthetic apparatus in wild-type A. thaliana and pif4, pif5, pif4pif5, and pif1pif3pif4pif5 mutants exposed to HIL for 0, 16, 32, or 48 h. Chlorophyll fluorescence parameters (Y(II), F_v/F_m, NPQ), net photosynthesis (Pn), transpiration rates, stomatal conductance (g_S), pigment contents and the expression of key genes were evaluated. The response of plants to HIL varied depending on the duration of exposure. After 16 h of irradiation, the greatest reductions in Pn and g_S were observed in the pif4pif5 and pif1pif3pif4pif5 mutants, whereas after 48 h, the decreases were most pronounced in the pif4, pif5, and pif4pif5 mutants. After 16 h of HIL exposure, the absence of pif4 and pif5 did not substantially alter the chlorophyll fluorescence parameters. However, after 48 h, both Y(II) and Fv/Fm were lower in these mutants than in the wild type, indicating changes in PSII functional status rather than direct reductions in photochemical quantum efficiency. At 16 h, chlorophyll levels were the highest in pif5 and WT, whereas anthocyanin and UV-absorbing pigment (UAP) levels were the highest in pif4, pif5 and WT. After 48 h, the highest levels of any pigments were detected in the WT and the pif1pif3pif4pif5 mutant. These results suggest that the accumulation of anthocyanins and UAPs under HIL is likely associated with the regulation of transcription factors, such as PIFs, de-etiolated 1 (DET1), constitutive photomorphogenic 1 (COP1), and elongated hypocotyl 5 (HY5). During prolonged HIL exposure, the absence of PIF4 and PIF5 has a critical impact on photosynthesis and the accumulation of photosynthetic pigments, whereas the simultaneous loss of PIF1, PIF3, PIF4, and PIF5 is less detrimental. This finding likely indicates opposite roles of PIF1 and PIF3 in the above-described processes, on the one hand, and PIF4 and PIF5, on the other hand, under HIL conditions. Full article

Background: The intravascular laser irradiation of blood (ILIB) is a low-power laser technique that has been studied since the 1970s, and it is associated with the substantial capability to modulate various physiological processes. Indeed, ILIB involves the irradiation of blood with low-intensity light, typically within the red or near-infrared spectrum, to trigger a cascade of photochemical and photobiological events. Objective: This study aimed to analyze previous findings regarding ILIB effects on physical performance. Methods: This study is a narrative review of the literature, addressing the effects of ILIB on multiple organ systems and its impact on physical performance. Results: The most found effects include antioxidant activation, inhibition of inflammatory processes, increased blood fluidity, and improved hemorheological properties. The ILIB affects blood rheological properties based on vasodilatation and decreasing aggregation of thrombocytes. Other effects include improved deformability of erythrocytes, which results in a better supply of oxygen and a decrease in the partial pressure of carbon dioxide. Since ILIB is a photobiomodulation procedure, other applications can be considered, such as ergogenic intervention. In this context, ILIB may favor performance in aerobic exercises and contribute to practices involving anaerobic metabolism by facilitating phosphocreatine resynthesis and ATP restoration. Conclusions: Multiple findings seek to support the potential benefits of ILIB on metabolic and cardiovascular responses associated with exercise training, providing potential improvements in athletic performance. Full article

Accurate assessment of vehicular air pollution in arid urban environments remains a challenge because standard emission models often overlook localized influences such as climate-driven dust resuspension and urban canyon effects. This study develops an enhanced modeling framework that integrates critical regional parameters into established algorithms to improve estimates of traffic-related emissions, including PM₁₀, PM₂.₅, CO, and NO₂. The US EPA’s AP-42 algorithm was modified to incorporate a novel highway width-to-building height ratio (I/H) and a climate-driven dynamic silt loading model derived from satellite data, while the European EEA algorithm was refined by introducing an explicit fuel density correction (ρ). The framework was applied and validated on two representative highways in Jordan—an industrial corridor and an urban-commercial artery—using continuous sensor-based measurements. Results indicate substantial improvement in predictive performance, with reductions of 60–77% in normalized difference for particulate matter and 72% for CO. The model successfully distinguished between emission regimes, capturing a seasonal silt-loading peak of approximately 17.5 g/m² during autumn at the industrial site, compared to more stable, traffic-dominated emissions along the urban corridor. Although NO₂ performance showed modest gains (4–40%) due to complex photochemical processes, the overall framework proved to be a robust and reliable tool for air quality assessment in arid cities. This adaptable approach provides a foundation for targeted air pollution management, and future work will integrate real-time dispersion dynamics and photochemical modules to better capture secondary pollutant formation. Full article

Heat-induced β-carotene synthesis in Dunaliella salina typically compromises biomass accumulation, resulting in a biomass–β-carotene trade-off. This study demonstrates that exogenous putrescine (Put) alleviates this conflict through temperature-dependent mechanisms. At 28 °C (optimal for growth), 10⁻⁶ M Put increased biomass by 9.52% and β-carotene yield by 10.72%, probably by accelerating electron transport and relatively mitigating the loss of photosynthetic function. At 34 °C (optimal for β-carotene synthesis), 10⁻⁷ M Put enhanced biomass by 9.68% and β-carotene yield by 35.71% through a process associated with nitric oxide (NO) accumulation, involving antioxidant synergy and controlled reactive oxygen species (ROS) signaling, which activated photoprotective carotenogenesis. At 40 °C (extreme thermal stress), 10⁻⁷ M Put maintained β-carotene levels 44.99% above the control despite a 2.50% biomass reduction, reflecting a shift toward photoprotection via elevated non-photochemical quenching (NPQ) and sustained electron transport beyond photosystem II (δ_RO). Put’s hierarchical modulation of redox homeostasis, photosystem plasticity, and NO signaling underpinned its temperature-dependent efficacy. Peak NO levels correlated with β-carotene yield, while thermodynamic enzyme denaturation at 40 °C limited protection. These findings establish a temperature–concentration framework for Put application that alleviates the biomass–β-carotene trade-off under climate variability. Full article

Avocado trees (Persea americana Mill.) grown in Mediterranean conditions are exposed to high temperatures and intense solar radiation during summer, factors that can severely compromise plant water status and key physiological processes. To minimize these stressful conditions, the use of shade nets is an agronomical technique that permits the creation of an optimal microclimate for crop development. Thus, the aim was to evaluate the effects of shade netting on the physiological response of young avocado trees commercially grown under Mediterranean climatic conditions. The main results showed similar circadian rhythms of plant water status under both crop systems (open-air and shaded) in both seasons. However, the use of shading nets altered the circadian rhythm of leaf gas exchange. In summer, stomatal conductance (g_s) remained significantly more open after midday in shaded trees, allowing higher leaf transpiration (E_leaf) and cooler leaf temperature (T_leaf). A similar daily pattern was observed in chlorophyll a fluorescence parameters, including the effective quantum yield of photosystem II (ΦPSII) and the electron transport rate (ETR), with the lowest values occurring at midday. In shaded plants, ΦPSII and ETR remained higher after midday than in open-air, suggesting a lower photochemical inhibition of photosynthesis caused by heat stress and photoinhibition. Thus, the use of shade nets represents an agronomic alternative technique for cultivating avocados in Mediterranean climate conditions. Full article

Organic chlorine (Org-Cl) in crude oil poses continuous operational and environmental risks during production, trading, and refining processes. This article reviews the management of Org-Cl from its origin assumptions to analysis and mitigation measures and proposes a practical closed-loop framework. Quantitative merit value indicators (typical detection limit/quantitative limit, accuracy, and repeatability) and greenness indicators are used to compare standard methods and advanced methods, and to guide the selection of applicable methods. Corresponding technical maturity levels (TRLs) are assigned to mitigation measures (protective beds/adsorption, HDC, and emerging electrochemical/photochemical routes). Technical economic indicators with reference values (relative capital expenditure/operating expenditure levels) are summarized to assist decision-making. The main findings are as follows: (i) Evidence of secondary formation of organic chlorine under distillation-related conditions still relies on the matrix and requires independent verification; (ii) MWDXRF can achieve rapid screening (usually only 5 to 10 min), while CIC/D5808 supports quality balance arbitration; (iii) adsorption can remove a considerable portion of organic chlorine in light fractions under laboratory conditions, while the survival ability of HDC related to crude oil depends on the durability of the catalyst and the tail gas treatment capacity; and (iv) minimum viable implementation (MVI) combined with online total-chlorine monitoring and a physical principle-based digital twin technology can provide auditable closed-loop control. The limitations of this review include partial reliance on laboratory-scale data, inconsistent reports among studies, and the lack of standardized public datasets for model benchmarking. Prioritization should be given to analysis quality control, process durability indicators, and data governance to achieve reliable digital deployment. Full article

Open urban environmental data offer a unique opportunity to connect scientific research, education, and citizen participation. Leveraging IoT-based sensor networks and AI-driven forecasting models, this study integrates open environmental data with reproducible analysis and learning workflows. This study presents a reproducible workflow developed in the Quarto–R environment to analyse and model air-quality dynamics in Madrid between 2020 and 2024. The workflow integrates data acquisition, validation, harmonisation, exploratory analysis, and forecasting using the Prophet model. The analysis focuses on nitrogen dioxide (NO₂) and ozone (O₃) as representative pollutants of traffic emissions and photochemical processes. Results show a marked decline in NO₂ concentrations across traffic stations and a parallel rise in O₃ levels in suburban areas, reflecting the combined effects of emission control and regional transport. Beyond its scientific contribution, the Quarto–R workflow functions as a pedagogical tool that embeds transparency, traceability, and active learning throughout the analytical process. By enabling students and researchers to reproduce every step, from raw data to interpreted results, it strengthens data literacy and fosters a deeper understanding of urban sustainability. The framework exemplifies how open data and reproducible computing can be integrated into STEM education and citizen-science initiatives, promoting both environmental awareness and methodological integrity, thus bridging artificial intelligence and experiential learning. Full article

The anodization of Ti° enables the formation of well-ordered TiO₂ nanotubes, a highly promising nanomaterial with exceptional photochemical properties and potential applications in the energy and environmental sectors. This study addresses the growth of TiO₂ nanotubes on large-scale surfaces applied for photocatalytic processes. The present investigation approaches the scaling up of the reactor for anodizing Ti°-coated flat surfaces and thus connecting the TiO₂-nano-structure with real-world applications. For this, 316 stainless steel sheets were coated with a uniform Ti° layer using the arc cathodic method. The results indicate that the (~3 µm) thick Ti° arc-PVD coatings are well anodized, despite the inherent amount of µm-sized droplets produced during the deposition. The results reported here highlight the effects of the anodization process parameters—voltage, current, and time—on nanotube growth. At 60 V, the nanotubes exhibited a highly uniform cylindrical morphology, homogeneous walls contributing to an ordered, stable, and open nanostructure at large Ti-coated surfaces. The scaling up of the reactor for the controlled anodization process of Ti° coating is addressed. This approach validates Ti°-based PVD coatings at a semi-industrial scale on commercial stainless steel, thus enabling affordable production costs. Lastly, the anodization of Ti° coatings is a viable, scalable manufacturing process for producing photocatalytic nanostructured surfaces. Full article