Low-Molecular-Weight, High-Mechanical-Strength, and Solution-Processable Telechelic Poly(ether imide) End-Capped with Ureidopyrimidinone

Solution-processable poly­(ether imide)­s (PEIs) with ureido­pyrimidinone (UPy) end groups were prepared by incorporating mono­isocyanato-6-methyl­isocytosine into amine-terminated PEI oligomers. After functionalization with UPy end groups, PEI with a molecular weight as low as 8 kDa (8k-PEI-UPy) can be solution-cast to form films. Tensile tests revealed that 8k-PEI-UPy had an outstanding Young’s modulus higher than those of state-of-the-art high-molecular-weight commercial PEIs. The tensile strength, maximum elongation, and Young’s modulus of 8k-PEI-UPy were 87.2 ± 10.8 MPa, 3.10 ± 0.39%, and (3.20 ± 0.14) × 10³ MPa, respectively. The discovery herein significantly advances the chemistry of high-temperature PEI resins. UPy-based supramolecular chemistry is an effective and general strategy to achieve outstanding mechanical properties for PEI oligomers

Practical Approach for Synthesis of 2-Amino-benzoxazole in Water

<div><p></p><p>A practical copper-catalyzed amination of benzoxazole with secondary amine in water has been developed. This reaction has proved to be effective to some cyclic amines, and the substituted group of nitrogen has a great impact on the amination reaction. A copper-catalyzed/ amine-induced ring opening of the benzoxazole and recyclization/oxidation mechanism was also proposed.</p></div

Defect-Electron Spreading on the TiO₂(110) Semiconductor Surface by Water Adsorption

The dissociative adsorption of water at oxygen-vacancy defect sites on the TiO₂(110) surface spatially redistributes the defect electron density originally present at subsurface sites near the defect sites. This redistribution of defect-electrons makes them more accessible to Ti⁴⁺ ions surrounding the defects. The redistribution of electron density decreases the O⁺ desorption yield from surface lattice O^2‑ ions in TiO₂, as excited by electron-stimulated desorption (ESD). A model in which OH formation on defect sites redistributes defect electrons to neighboring Ti⁴⁺ sites is proposed. This switches off the Knotek–Feibelman mechanism for ESD of O⁺ ions from lattice sites. Conversely, enhanced O⁺ reneutralization could also be induced by redistribution of defect electrons. The redistribution of surface electrons by adsorption is further verified by the use of donor and acceptor molecules that add or remove electron density

Facile Template-Free Fabrication of Aluminum-Organophosphorus Hybrid Nanorods: Formation Mechanism and Enhanced Luminescence Property

Recently, much effort has been directed toward fabrication of metal-organophosphorus hybrids with microporous, fibered, layered, and open structures to obtain desired mechanical, optical, electric, and catalytic properties. In this work, aluminum–phosphorus hybrid nanorods (<b>APHNRs</b>) with regular morphology were prepared by a template-free hydrothermal reaction of aluminum hydroxide with diphenylphosphinic acid (DPPA). Structure characterization of <b>APHNRs</b> by Fourier transform infrared spectroscopy, laser Raman spectroscopy, and X-ray diffraction demonstrate a structure with aluminophosphate main chains and phenyl pendant groups, which enable self-assembly into nanorods. The reaction conditions and the structures of phosphinic acids appear to have a significant impact on the morphology and size of nanorods. Moreover, the evolution of morphology and structure assembly during the forming process of <b>APHNRs</b>, as monitored by SEM and XRD, reveal a decomposition-assembly propagation process where the driving force of assembly is attributed to π–π stacking interactions between phenyl pendant groups. <b>APHNRs</b> show a significant increase in light emission relative to pure DPPA due to their compact structure resulting from the π–π stacking interaction. Detailed investigation revealed that photoluminescence was remarkably amplified by enhancing the compactness of <b>APHNRs</b>

MnO₂‑Nanosheet-Powered Protective Janus DNA Nanomachines Supporting Robust RNA Imaging

Both biomarker and probe degradations cause serious false assay results. However, protecting a target or a target and a probe simultaneously has rarely been explored. Herein, MnO₂-nanosheet-powered target- and probe-protective Janus DNA nanomachines are reported. It is formed in living cells by an RNA-responsive assembly of two chemically modified DNA partzymes and one substrate probe. MnO₂ nanosheets are used to facilitate the cellular uptake of DNA reagents and generate Mn²⁺, which are indispensable DNAzyme cofactors for efficient catalytic cleavage. We find that DNA partzymes with modified sugar moieties (e.g., LNA or ones with 2′-O-methylation) protect the RNA of RNA–DNA hybrids from RNase H degradation. LNA blocks RNase H recruitment on the hybrid best because of its 2′-O, 4′-C methylene bridge structure. In contrast, modifications at DNA phosphate moieties fail to protect the RNA. RNA protection can exclude target-degradation-induced false negative results. In addition, the phosphorothioate-modified substrate probe is known to resist nuclease degradation, which minimizes false positive interference. Compared to canonical DNA systems without chemical modifications, the protective Janus nanomachine avoids false results and supports robust RNA imaging

Palladium-Catalyzed Selective Mono-/Tetraacetoxylation of <i>o</i>‑Carboranes with Acetic Acid via Cross Dehydrogenative Coupling of Cage B–H/O–H Bonds

A selective mono-/tetraacetoxylation of <i>o</i>-carboranes with acetic acid via cross dehydrogenative coupling of cage B–H/O–H bonds has been developed, and a series of mono- and tetraacetoxylated <i>o</i>-carboranes have been synthesized with moderate to good yields as well as good selectivity. Mechanistic studies indicate that the acetoxyl originates from acetic acid directly, and a nucleophilic addition of Pd^IV-oxo species and dehydration process is proposed

Analysis of anti-asthmatic drug patents published in China between 2004 and 2013

<p><b>Introduction</b>: We previously reported that 789 anti-allergic patents were granted in China between 1988 and 2008, but the number of patents seems to have grown much faster in China in recent years. Therefore, it is necessary to analyse the patents for anti-asthmatic products between 2004 and 2013 to give pharmaceutical companies and individuals a better understanding of potential candidates for anti-asthmatic drug development from patents published in China.</p> <p><b>Areas covered</b>: The current report analyses the scientific progress that supports anti-asthmatic drug patent applications and reviews the published patent literature in China from 2004 to 2013.</p> <p><b>Expert opinion</b>: The rapid increase in the number of anti-asthmatic patents in China indicates that more specific discoveries have been made and that more people are aware of the importance of intellectual property protection in China. Holding patents may guarantee protection for an innovative new product.</p

Graphene-Bridged Multifunctional Flexible Fiber Supercapacitor with High Energy Density

Portable fiber supercapacitors with high-energy storage capacity are in great demand to cater for the rapid development of flexible and deformable electronic devices. Hence, we employed a 3D cellular copper foam (CF) combined with the graphene sheets (GSs) as the support matrix to bridge the active material with nickel fiber (NF) current collector, significantly increasing surface area and decreasing the interface resistance. In comparison to the active material directly growing onto the NF in the absence of CF and GSs, our rationally designed architecture achieved a joint improvement in both capacity (0.217 mAh cm^–2/1729.413 mF cm^–2, 1200% enhancement) and rate capability (87.1% from 1 to 20 mA cm^–2, 286% improvement), which has never been achieved before with other fiber supercapacitors. The in situ scanning electron microscope (SEM) microcompression test demonstrated its superior mechanical recoverability for the first time. Importantly, the assembled flexible and wearable device presented a superior energy density of 109.6 μWh cm^–2 at a power density of 749.5 μW cm^–2, and the device successfully coupled with a flexible strain sensor, solar cell, and nanogenerator. This rational design should shed light on the manufacturing of 3D cellular architectures as microcurrent collectors to realize high energy density for fiber-based energy storage devices

Graphene-Bridged Multifunctional Flexible Fiber Supercapacitor with High Energy Density

Portable fiber supercapacitors with high-energy storage capacity are in great demand to cater for the rapid development of flexible and deformable electronic devices. Hence, we employed a 3D cellular copper foam (CF) combined with the graphene sheets (GSs) as the support matrix to bridge the active material with nickel fiber (NF) current collector, significantly increasing surface area and decreasing the interface resistance. In comparison to the active material directly growing onto the NF in the absence of CF and GSs, our rationally designed architecture achieved a joint improvement in both capacity (0.217 mAh cm^–2/1729.413 mF cm^–2, 1200% enhancement) and rate capability (87.1% from 1 to 20 mA cm^–2, 286% improvement), which has never been achieved before with other fiber supercapacitors. The in situ scanning electron microscope (SEM) microcompression test demonstrated its superior mechanical recoverability for the first time. Importantly, the assembled flexible and wearable device presented a superior energy density of 109.6 μWh cm^–2 at a power density of 749.5 μW cm^–2, and the device successfully coupled with a flexible strain sensor, solar cell, and nanogenerator. This rational design should shed light on the manufacturing of 3D cellular architectures as microcurrent collectors to realize high energy density for fiber-based energy storage devices

Graphene-Bridged Multifunctional Flexible Fiber Supercapacitor with High Energy Density

Portable fiber supercapacitors with high-energy storage capacity are in great demand to cater for the rapid development of flexible and deformable electronic devices. Hence, we employed a 3D cellular copper foam (CF) combined with the graphene sheets (GSs) as the support matrix to bridge the active material with nickel fiber (NF) current collector, significantly increasing surface area and decreasing the interface resistance. In comparison to the active material directly growing onto the NF in the absence of CF and GSs, our rationally designed architecture achieved a joint improvement in both capacity (0.217 mAh cm^–2/1729.413 mF cm^–2, 1200% enhancement) and rate capability (87.1% from 1 to 20 mA cm^–2, 286% improvement), which has never been achieved before with other fiber supercapacitors. The in situ scanning electron microscope (SEM) microcompression test demonstrated its superior mechanical recoverability for the first time. Importantly, the assembled flexible and wearable device presented a superior energy density of 109.6 μWh cm^–2 at a power density of 749.5 μW cm^–2, and the device successfully coupled with a flexible strain sensor, solar cell, and nanogenerator. This rational design should shed light on the manufacturing of 3D cellular architectures as microcurrent collectors to realize high energy density for fiber-based energy storage devices