Effects of the supernatant of Chlorella vulgaris cultivated under different culture modes on lettuce (Lactuca sativa L.) growth.

CO2 capture by microalgae is a feasible strategy to reduce CO2 emissions. However, large amounts of cell-free supernatant will be produced after microalgal harvesting, which may be harmful to the environment if it is disorderly discharged. In this study, Chlorella vulgaris (C. vulgaris) was cultivated under three common cultivation modes (autotrophic culture (AC), heterotrophic culture (HC) and mixotrophic culture (MC)), and the obtained supernatant was used as fertilizer to investigate its effect on the growth of lettuce. The biomass concentration of C. vulgaris cultivated under MC and HC was 3.25 and 2.59 times that of under AC, respectively. The contents of macronutrients in supernatant obtained from AC were higher than those of MC and HC. However, the contents of amino acids and hormones in supernatant obtained from MC and HC were higher than those of AC. The fresh shoot weight, fresh root weight and root length of lettuce treated with supernatant were significantly higher than that of control treatment. In addition, the contents of chlorophyll, soluble sugar and soluble protein in lettuce treated with supernatant were also higher than that of control treatment. However, the contents of nitrate in lettuce treated with supernatant was lower than that of control treatment. These results showed that the supernatant could promote the growth of lettuce and was a potential of fertilizer for crop planting.

Causal association between 25-hydroxyvitamin D status and cataract development: A two-sample Mendelian randomization study.

BACKGROUND: Vitamin deficiencies are linked to various eye diseases, and the influence of vitamin D on cataract formation has been noted in prior research. However, detailed investigations into the causal relationship between 25-(OH)D status and cataract development remain scarce. AIM: To explore a possible causal link between cataracts and vitamin D. METHODS: In this study, we explored the causal link between 25-(OH)D levels and cataract development using Mendelian randomization. Our analytical approach included inverse-variance weighting (IVW), MR-Egger, weighted median, simple mode, and weighted mode methods. The primary analyses utilized IVW with random effects, supplemented by sensitivity and heterogeneity tests using both IVW and MR-Egger. MR-Egger was also applied for pleiotropy testing. Additionally, a leave-one-out analysis helped identify potentially impactful single-nucleotide polymorphisms. RESULTS: The analysis revealed a positive association between 25-(OH)D levels and the risk of developing cataracts (OR = 1.11, 95%CI: 1.00-1.22; P = 0.032). The heterogeneity test revealed that our IVW analysis exhibited minimal heterogeneity (P > 0.05), and the pleiotropy test findings confirmed the absence of pleiotropy within our IVW analysis (P > 0.05). Furthermore, a search of the human genotype-phenotype association database failed to identify any potentially relevant risk-factor single nucleotide polymorphisms. CONCLUSION: There is a potential causal link between 25-(OH)D levels and the development of cataracts, suggesting that greater 25-(OH)D levels may be a contributing risk factor for cataract formation. Further experimental research is required to confirm these findings.

Reductive Carbon-Carbon Coupling on Metal Sites Regulates Photocatalytic CO2 Reduction in Water Using ZnSe Quantum Dots.

Colloidal quantum dots (QDs) consisting of precious-metal-free elements show attractive potentials towards solar-driven CO2 reduction. However, the inhibition of hydrogen (H2 ) production in aqueous solution remains a challenge. Here, we describe the first example of a carbon-carbon (C-C) coupling reaction to block the competing H2 evolution in photocatalytic CO2 reduction in water. In a specific system taking ZnSe QDs as photocatalysts, the introduction of furfural can significantly suppress H2 evolution leading to CO evolution with a rate of ≈5.3 mmol g-1 h-1 and a turnover number (TON) of >7500 under 24 h visible light. Meanwhile, furfural is upgraded to the self-coupling product with a yield of 99.8 % based on the consumption of furfural. Mechanistic insights show that the reductive furfural coupling reaction occurs on surface Zn-sites to consume electrons and protons originally used for H2 production, while the CO formation pathway at surface anion vacancies from CO2 remains.

Rational Design of Dot-on-Rod Nano-Heterostructure for Photocatalytic CO2 Reduction: Pivotal Role of Hole Transfer and Utilization.

Inspired by green plants, artificial photosynthesis has become one of the most attractive approaches toward carbon dioxide (CO2 ) valorization. Semiconductor quantum dots (QDs) or dot-in-rod (DIR) nano-heterostructures have gained substantial research interest in multielectron photoredox reactions. However, fast electron-hole recombination or sluggish hole transfer and utilization remains unsatisfactory for their potential applications. Here, the first application of a well-designed ZnSe/CdS dot-on-rods (DORs) nano-heterostructure for efficient and selective CO2 photoreduction with H2 O as an electron donor is presented. In-depth spectroscopic studies reveal that surface-anchored ZnSe QDs not only assist ultrafast (≈2 ps) electron and hole separation, but also promote interfacial hole transfer participating in oxidative half-reactions. Surface photovoltage (SPV) spectroscopy provides a direct image of spatially separated electrons in CdS and holes in ZnSe. Therefore, ZnSe/CdS DORs photocatalyze CO2 to CO with a rate of ≈11.3 µmol g-1 h-1 and ≥85% selectivity, much higher than that of ZnSe/CdS DIRs or pristine CdS nanorods under identical conditions. Obviously, favored energy-level alignment and unique morphology balance the utilization of electrons and holes in this nano-heterostructure, thus enhancing the performance of artificial photosynthetic solar-to-chemical conversion.

Semiconductor nanocrystals for small molecule activation via artificial photosynthesis.

Facile activation and conversion of small molecules (e.g., H2O, CO2, N2, CH4, and C6H6) into solar fuels or value-added chemicals under mild conditions is an attractive pathway in dealing with the worldwide appeal of energy consumption and the growing demand of industrial feedstocks. Compared with conventional thermo- or electro-catalytic approaches, the protocol of photocatalysis shines light on green and low-cost storage of sunlight in chemical bonds. For instance, artificial photosynthesis is an effective way to split H2O into molecular O2 and H2, thereby storing solar energy in the form of hydrogen fuel. Because of rational tunability in band gaps, charge-carrier dynamics, exposed active sites and catalytic redox activities by tailoring size, composition, morphology, surface, and/or interface property, semiconductor nanocrystals (NCs) emerge as very promising candidates for photo-induced small molecule activation, including H2O splitting, CO2 reduction, N2 fixation, CH4 conversion and chemical bond formation (e.g., S-S, C-C, C-N, C-P, C-O). In this review, we summarize the recent advances in small molecule activation via artificial photosynthesis using semiconductor NCs, especially those consisting of II-VI and III-V elements. Moreover, we highlight the intrinsic advantages of semiconductor NCs in this field and look into the fabrication of prototype devices for large-scale and sustainable small molecule activation to store solar energy in chemical bonds.

Exploring the Reducing Ability of Organic Dye (Acr+-Mes) for Fluorination and Oxidation of Benzylic C(sp3)-H Bonds under Visible Light Irradiation.

The excellent oxidizing capability of acridinium-based organic dye (Acr+-Mes) is fully studied in photoredox catalysis. However, its reducing ability is always considered weak for organic transformation. The reducing ability of Acr+-Mes is developed by Selectfluor to achieve effective fluorination and oxidation of benzylic C(sp3)-H bonds under visible light irradiation, which is not available for the direct use of oxidizing ability of excited Acr+-Mes. Mechanistic insights provided strong evidence for the oxidative quenching of Acr+-Mes.