Two-dimensional (2D) perovskites are emerging photovoltaic materials because of their highly tunable photophysical properties and improved environmental stability in comparison with 3D perovskites. Here, a thiophene-based bulky dication spacer, namely, 2,5-thiophenedimethyl­ammonium (ThDMA), was developed and applicated in 2D Dion–Jacobson (DJ) perovskite. High-quality 2D DJ perovskite, (ThDMA)­(MA) n–1Pb n I3n+1 (nominal n = 5), with improved crystallinity, preferred vertical orientation, and enlarged spatially resolved carrier lifetime could be achieved by a one-step method using a mixed solvent of DMF/DMSO (v/v, 9:1). The optimized device exhibits a high efficiency of 15.75%, which is a record for aromatic spacer-based 2D DJ perovskite solar cells (PSCs). Moreover, the unencapsulated 2D DJ perovskite devices sustained over 95% of their original efficiency after storage in N2 for 1655 h. Importantly, both the light-soaking stability and thermal stability (T = 80 °C) of the 2D DJ perovksite devices are dramatically improved in comparison with their 3D counterparts. These results indicate that highly efficient and stable 2D DJ PSCs could be achieved by developing thiophene-based aromatic spacers as well as device engineering.

Formamidinium (FA)‐based 3D perovskite solar cells (PSCs) have been widely studied and they show reduced bandgap, enhanced stability, and improved efficiency compared to MAPbI3‐based devices. Nevertheless, the FA‐based spacers have rarely been studied for 2D Ruddlesden–Popper (RP) perovskites, which have drawn wide attention due to their enormous potential for fabricating efficient and stable photovoltaic devices. Here, for the first time, FA‐based derivative, 2‐thiopheneformamidinium (ThFA), is successfully synthesized and employed as an organic spacer for 2D RP PSCs. A precursor organic salts‐assisted crystal growth technique is further developed to prepare high quality 2D (ThFA)2(MA)n−1PbnI3n+1 (nominal n = 3) perovskite films, which shows preferential vertical growth orientations, high charge carrier mobilities, and reduced trap density. As a result, the 2D RP PSCs with an inverted planar p‐i‐n structure exhibit a dramatically improved power conversion efficiency (PCE) from 7.23% to 16.72% with negligible hysteresis, which is among the highest PCE in 2D RP PSCs with low nominal n‐value of 3. Importantly, the optimized 2D PSCs exhibit a dramatically improved stability with less than 1% degradation after storage in N2 for 3000 h without encapsulation. These findings provide an effective strategy for developing FA‐based organic spacers toward highly efficient and stable 2D PSCs.

Ultraviolet‐B (UV‐B) radiation and low temperature promote the accumulation of anthocyanins, which give apple skins their red colour. Although many transcription regulators have been characterized in the UV‐B and low‐temperature pathways, their interregulation and synergistic effects are not well understood. Here, a B‐box transcription factor gene, MdBBX20, was characterized in apple and identified to promote anthocyanin biosynthesis under UV‐B conditions in field experiments and when overexpressed in transgenic apple calli. The transcript level of MdBBX20 was significantly induced by UV‐B. Specific G‐box elements in the promoters of target genes were identified as interaction sites for MdBBX20. Further experimental interrogation of the UV‐B signalling pathways showed that MdBBX20 could interact with MdHY5 in vitro and in vivo and that this interaction was required to significantly enhance the promoter activity of MdMYB1. MdBBX20 also responded to low temperature (14°C) with the participation of MdbHLH3, which directly bound a low temperature‐response cis elements in the MdBBX20 promoter. These findings demonstrate the molecular mechanism by which MdBBX20 integrates low‐temperature‐ and UV‐B‐induced anthocyanin accumulation in apple skin.

Layered two-dimensional (2D) perovskites are emerging photovoltaic materials due to their good environmental and structural stability thanks to the bulky organic spacers incorporated in the crystal lattice. Formamidine (FA) is an indispensable organic cation in high-performance 3D perovskite materials, whereas FA derivative-based spacers have remained largely unexplored in 2D perovskite. Here, we demonstrated a class of aromatic formamidinium (ArFA) spacers, namely, benzamidine (PhFA) and para-fluorobenzamidine (p-FPhFA), for efficient 2D Ruddlesden–Popper (RP) perovskite solar cells. It is found that the 2D perovskite with the fluorinated spacer p-FPhFA shows significantly improved charge carrier lifetime, enhanced mobility, and reduced trap density in comparison with an unfluorinated PhFA spacer. As a result, the p-FPhFA-based 2D perovskite (n = 5) device yields a champion efficiency of 17.37%, which is much higher than that of the PhFA-Pb device (12.92%), representing a record value for 2D PSCs with FA-based spacers. These results highlight the great potential of ArFA spacers, especially the fluorinated ArFA spacer, for high-performance 2D perovskite solar cells.

Genes SNO1 and SNZ1 are Saccharomyces cerevisiae homologues of PDX2 and PDX1 which participate in pyridoxine synthesis in the fungus Cercospora nicotianae. In order to clarify their function, the two genes SNO1 and SNZ1 were expressed in Escherichia coli either individually or simultaneously and with or without a His-tag. When expressed simultaneously, the two protein products formed a complex and showed glutaminase activity. When purified to homogeneity, the complex exhibited a specific activity of 480 nmolAEmg )1 AEmin)1 as glutaminase, with a K m of 3.4 mM for glutamine. These values are comparable to those for other glutamine amidotransferases. In addition, the glutaminase activity was impaired by 6-diazo-5-oxo-L-norleucine in a time-and dose-dependent manner and the enzyme was protected from deactivation by glutamine. These data suggest strongly that the complex of Sno1p and Snz1p is a glutamine amidotransferase with the former serving as the glutaminase, although the activity was barely detectable with Sno1p alone. The function of Snz1p and the amido acceptor for ammonia remain to be identified.

Two-dimensional Dion–Jacobson (DJ) perovskites have shown improved structure stability in comparison with Ruddlesden–Popper (RP) perovskites. However, the mechanism behind the improved stability is still largely unexplored. Here a multifluorinated aromatic spacer, namely, 4F-PhDMA, has been successfully developed for 2D DJ perovskites. It is found that the 2D DJ perovskite with a 4F-PhDMA spacer exhibits a high dissociation energy due to the multiple noncovalent interactions. The optimized 2D DJ device based on the 4F-PhDMA spacer (n = 4) exhibits a champion efficiency of 16.62% with much improved light and thermal stability. This efficiency is much higher than that of the control device using an unfluorinated spacer (n = 4, PCE = 10.11%) and is among the highest efficiencies in aromatic-spacer-based 2D DJ perovskite solar cells (PSCs). Our work highlights the importance of incorporating multiple noncovalent interactions in the 2D DJ perovskite by employing a multifluorinated aromatic spacer to achieve DJ PSCs with both high efficiency and high stability.

Polyphenols are micronutrients that are widely present in human daily diets. Numerous studies have demonstrated their potential as antioxidants and anti-inflammatory agents, and for cancer prevention, heart protection and the treatment of neurodegenerative diseases. However, due to their vulnerability to environmental conditions and low bioavailability, their application in the food and medical fields is greatly limited. Nanoformulations, as excellent drug delivery systems, can overcome these limitations and maximize the pharmacological effects of polyphenols. In this review, we summarize the biological activities of polyphenols, together with systems for their delivery, including phospholipid complexes, lipid-based nanoparticles, protein-based nanoparticles, niosomes, polymers, micelles, emulsions and metal nanoparticles. The application of polyphenol nanoparticles in food and medicine is also discussed. Although loading into nanoparticles solves the main limitation to application of polyphenolic compounds, there are some concerns about their toxicological safety after entry into the human body. It is therefore necessary to conduct toxicity studies and residue analysis on the carrier.

Exogenously applied caveolin-1 scaffolding domain (CAV) has been shown to inhibit inflammatory mediator-induced nitric oxide (NO) production and NO-mediated increases in microvessel permeability. However, the effect of CAV on endothelial basal NO that prevents leukocyte adhesion remains unknown. This study aims to investigate the roles of exogenously applied CAV in endothelial basal NO production, leukocyte adhesion, and adhesion-induced changes in microvessel permeability. Experiments were conducted in individually perfused rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (Lp). NO was quantified with fluorescence imaging in DAF-2-loaded vessels. Perfusing venules with CAV inhibited basal NO production without affecting basal Lp. Resuming blood flow in CAV-perfused vessels significantly increased leukocyte adhesion. The firmly adherent leukocytes altered neither basal Lp nor adherens junction integrity. Increases in Lp occurred only upon formyl-Met-Leu-Phe application that induces release of reactive oxygen species from the adherent leukocytes. The application of NO synthase inhibitor showed similar results to CAV, and NO donor abolished CAV-mediated leukocyte adhesion. Immunofluorescence staining showed increases in binding of ICAM-1 to an adhesion-blocking antibody concurrent with a Src-dependent ICAM-1 phosphorylation following CAV perfusion. Pre-perfusing vessels with anti-ICAM-1 blocking antibody or a Src kinase inhibitor attenuated CAV-induced leukocyte adhesion. These results indicate that the application of CAV, in addition to preventing excessive NO-mediated permeability increases, also causes reduction of basal NO and promotes ICAM-1-mediated leukocyte adhesion through Src activation-mediated ICAM-1 phosphorylation. CAV-induced leukocyte adhesion was uncoupled from leukocyte oxidative burst and microvessel barrier function, unless in the presence of a secondary stimulation.