Hyperbranched Phosphorus-Containing Benzoxazine for Epoxy Modification: Flame Retardant and Toughening Agent

To overcome the high flammability and brittleness of epoxy resin (EP) without sacrificing its glass transition temperature (Tg) and mechanical properties, a series of hyperbranched benzoxazines (HB1.0–HB2.5) were synthesized using 6-(bis­(4-hydroxyphenyl)­methyl)­dibenzo­[1,2]­oxaphosphinine 6-oxide (DOPO-2OH) as the “hard” segment and Jeffamine T403 as the “soft” segment. The property investigation revealed that HB2.0 with the optimized ratio of “hard/soft” segments was the appropriate additive for commercial EP. Furthermore, the comprehensive performance of the EP/HB2.0 system was significantly enhanced compared to the pristine EP, demonstrating a 115% increase in impact strength and 5.7 °C in Tg. Impressively, when the loading of HB2.0 was only 10 phr (phosphorus content is 0.34 wt %), the modified EP passed the UL-94 V-0 rating and achieved a limited oxygen index (LOI) value of 30.8%, mainly resulting from the flame inhibition effect of the gaseous phase. This research provided an appealing technique for simultaneously improving the toughness and flame retardancy of EP

Benchmarking the pH–Stability Relationship of Metal Oxide Anodes in Anion Exchange Membrane Water Electrolysis

Anion exchange membrane water electrolysis (AEMWE) is one of the most promising technologies for producing green hydrogen; however, they still suffer from durability issues. One task is to find suitable electrolyte conditions for anode catalysts that endow them with both high activity and stability. Herein, we benchmark the pH–stability relationship of four typical metal oxides as anode catalysts in the AEMWE. Their electrochemical performance and structural stability were in-depth analyzed through impedance, dissolved composition in the electrolyte, and correlated Pourbaix diagram. NiFe2O4 with the best activity and stability in the strong alkaline (pH = 14) shows terrible stability in pure water, which is then verified due to the severe Fe leaching, and it cannot be alleviated by alkaline pre-activation. Notably, Co3O4 shows comparable activity and stability to IrO2 in pure water and weak alkaline conditions. At pH = 12, it entails only ∼2.18 V to reach 1.0 A cm–2 and stabilizes for 40 h, being superior to others. This work screens out suitable transition metal oxides as a substitute for noble metals and their optimal application scenarios for AEMWE

Data_Sheet_1_Dominant Dendrobium officinale mycorrhizal partners vary among habitats and strongly induce seed germination in vitro.pdf

Dendrobium officinale (Orchidaceae) is an endangered epiphytic orchid that has been well studied as a medicinal plant. Although previous studies have shown that various fungal isolates promote D. officinale seed germination and seedling development in vitro, mycorrhizal associations among its wild populations remain poorly understood. In this study, we identified mycorrhizal fungi associated with D. officinale (36 individuals from six sites) using Sanger sequencing and compared fungal communities among sites and habitats (lithophytic vs. epiphytic individuals). Among the obtained sequences, 76 belonged to orchid mycorrhizal fungi (OMF), among which Tulasnellaceae accounted for 45.8% and Serendipitaceae for 28.1%. The Serendipitaceae operational taxonomic unit (OTU) SE1 was the most dominant partner, accounting for 27.1% of all detected fungal sequences, followed by a Tulasnellaceae OTU, TU27, which accounted for 15.6%. The relative frequencies of Serendipitaceae and Tulasnellaceae differed greatly between lithophytic and epiphytic individuals. Serendipitaceae accounted for 47.3% of the OMF sequences among lithophytes, and Tulasnellaceae for 95.2% among epiphytes. Mycorrhizal community composition also varied among sites. We further conducted in vitro symbiotic culture from seeds with six fungal isolates. Two Serendipitaceae and two Tulasnellaceae isolates, including SE1 and TU27, significantly promoted seed germination and seedling development. These results indicate that D. officinale is mainly associated with Tulasnellaceae and Serendipitaceae as its main fungal partners, which strongly induced seed germination and seedling development in vitro, suggesting their association with D. officinale through its life cycle.</p

Design of a Low-Temperature Ring-Opening Benzoxazine System Using a Supramolecular Hydrogen-Bond Structure

Phenolic derivatives capable of reducing the ring-opening temperature of benzoxazine resin have gradually emerged as valuable modules for benzoxazine chemistry, not to mention their good compatibility, coreactivity, and network modifiability. However, the previously reported unsatisfactory promotion effects, unclear reaction mechanisms, and unstable structure have severely limited the development of benzoxazine/phenol systems. Herein, a supramolecular hydrogen-bonded system consisting of resorcinol and 2-aminopyridine benzoxazine (PH-2a) was developed. The PH-2a/resorcinol mixture system with an equivalence ratio of 1:1 exhibited a dramatic reduction in ring-opening peak temperature (Tp) from 283 to 110 °C. Experimental combined with computational investigations supported its supramolecular H-bond behavior. Based on the cross-comparison of PH-2a analogues and other diphenols, the critical roles of H-bonding interactions both in activating reactants and inducing a directional reaction were revealed. These H-bonds with appropriate strengths can self-assembly form and close the distance between potential reaction sites, facilitating the direct production of an adduct. In addition, the application potential of the PH-2a/resorcinol system was also prospected, which can promise network tailoring and low-temperature cross-linking by the design flexibility of PH-2a and resorcinol derivatives, opening up possibilities for the preparation of advanced polybenzoxazine resins at low temperature

Additional file 1 of Functions of retinal astrocytes and Müller cells in mammalian myopia

Additional file 1

Additional file 2 of Functions of retinal astrocytes and Müller cells in mammalian myopia

Additional file 2

Hybrid Catalyst Coupling Single-Atom Ni and Nanoscale Cu for Efficient CO₂ Electroreduction to Ethylene

A hybrid catalyst with integrated single-atom Ni and nanoscale Cu catalytic components is reported to enhance the C–C coupling and ethylene (C2H4) production efficiency in the electrocatalytic CO2 reduction reaction (eCO2RR). The single-atom Ni anchored on high-surface-area ordered mesoporous carbon enables high-rate and selective conversion of CO2 to CO in a wide potential range, which complements the subsequent CO enrichment on Cu nanowires (NWs) for the C–C coupling to C2H4. In situ surface-enhanced infrared absorption spectroscopy (SEIRAS) confirms the substantially improved CO enrichment on Cu, once the incorporation of single-atom Ni occurs. Also, in situ X-ray absorption near-edge structure (XANES) demonstrates the structural stability of the hybrid catalyst during eCO2RR. By modulating hybrid compositions, the optimized catalyst shows 66% Faradaic efficiency (FE) in an alkaline flow cell with over 100 mA·cm–2 at −0.5 V versus reversible hydrogen electrode, leading to a five-order enhancement in C2H4 selectivity compared with single-component Cu NWs