摘要 : Traumatic brain injury (TBI) is one of the most dangerous acute diseases resulting in high morbidity and mortality. Current methods remain limited with respect to early diagnosis and real‐time feedback on the pathological process. Herein, a targeted activatable fluorescent nanoprobe (V&A@Ag2S) in the second near‐infrared window (NIR‐II) is presented for in vivo optical imaging of TBI. Initially, the fluorescence of V&A@Ag2S is turned off owing to energy transfer from Ag2S to the A1094 chromophore. Upon intravenous injection, V&A@Ag2S quickly accumulates in the inflamed vascular endothelium of TBI based on VCAM1‐mediated endocytosis, after which the nanoprobe achieves rapid recovery of the NIR‐II fluorescence of Ag2S quantum dots (QDs) owing to the bleaching of A1094 by the prodromal biomarker of TBI, peroxynitrite (ONOO−). The nanoprobe offers high specificity, rapid response, and high sensitivity toward ONOO−, providing a convenient approach for in vivo early real‐time assessment of TBI.

摘要 : Future renewable energy supplies and a sustainable environment rely on many important catalytic processes. Single‐atom catalysts (SACs) are attractive because of their maximum atom utilization efficiency, tunable electronic structures, and outstanding catalytic performance. Of particular note, transition‐metal SACs exhibit excellent catalytic activity and selectivity for the oxygen reduction reaction (ORR)—an important half reaction in fuel cells and metal–air batteries as well as for portable hydrogen peroxide (H2O2) production. Although considerable efforts have been made on the synthesis of SACs for ORR, the regulation of the coordination environments of SACs and thus the electronic structures still pose a big challenge. In this review, strategies for manipulating the coordination environments of SACs are classified into three categories, including regulation of the center metal atoms, manipulation of the surrounding environment connecting to the center metal atom, and modification of the geometric configuration of the support. Finally, some issues regarding the future development of SACs for ORR are raised and possible solutions are proposed.

摘要 : To enhance the ability to remove mercury(II) from aqueous media, an Fe3O4 magnetic nanocomposite (PPy–GO) composed of polypyrrole (PPy) and graphene oxide (GO) was synthesized in situ and characterized via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), zeta potential analysis, vibrating sample magnetometer (VSM) and the Brunauer–Emmett–Teller (BET) method. The performance of the magnetic PPy–GO for adsorbing mercury(II) from water along with the effects of solution pH, adsorbent dosage, coexisting ions, reaction time and temperature were studied in detail. The adsorption kinetics, isotherms and thermodynamics were investigated in detail to gain insights into the adsorption process. The results show that the BET surface area of the magnetic PPy–GO reached 1737.6 m2 g−1. The Langmuir capacity of the magnetic PPy–GO for mercury(II) adsorption was 400.0 mg g−1 at 300 K and pH 7 ± 0.1. After adsorption, the magnetic PPy–GO nanocomposite could be efficiently separated from water via a magnetic field. The adsorption process was endothermic and spontaneous and occurred in accord with the Langmuir and pseudo-second-order models. The overall adsorption of mercury(II) not only involved chemisorption, but was also partially governed by intra-particle diffusion. Data from the preliminary application of magnetic PPy–GO to remove heavy metals from real electroplating effluent indicated a high removal efficiency of over 99% for mercury(II). Finally, a possible adsorption mechanism was discussed. All data showed that the magnetic PPy–GO material is a promising adsorbent to remove mercury(II) from aqueous media.

摘要 : Membrane proteins perform a variety of functions vital to the survival of organisms, such as oxidoreductase, transferase or hydrolase. If the type of membrane protein can be detected, the function of protein can be quickly determined. Many existing computational methods not only use the autocorrelation function on the hydrophobicity index of amino acids, but also consider the evolutionary conservatism information of the primary protein sequences. In this study, we employ Average Blocks (AvBlock), Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT), Histogram of Oriented Gradient (HOG) and Pseudo-PSSM (PsePSSM) to extract evolution characteristics from Position-Specific Score Matrix (PSSM). Then, we construct five kernels from above five corresponding feature sets. Finally, we propose a novel Multiple Kernel Support Vector Machine (MKSVM) classifier based on Hilbert Schmidt Independence Criterion (HSIC) to integrate five kernels for identifying membrane proteins. For the performance evaluation, our method is tested on four benchmark datasets of membrane proteins. The comparative results demonstrate that our prediction model achieves the best performance among all existing outstanding approaches.

摘要 : Thermal energy storage technologies based on phase change materials (PCM) have been increasingly studied because of their superb regulation of thermal energy and their recent increases in efficient energy utilization. However, the low thermal conductivity of pure PCM immensely restricts their use in some applications such as the thermal management of devices and wearable textiles. Adding highly thermal conductive nanoadditives to PCM is widely accepted as a highly effective strategy to enhance the thermal conductivity of PCM. In this review, a comprehensive summary of the recent advances in enhancing thermal conductivity of PCM based on different dimensional nanoadditives is proposed, including zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) nanoadditives along with hybrid nanoadditives. We emphasize the fundamental thermal mechanisms : phonon transport, interfacial thermal resistance, thermal conductive architectures, and thermal conductivity. Furthermore, we systematically compare the traits and differences of different dimensional nanoadditives and their construction of thermally conductive pathways on the thermal conductivity enhancement of PCM. Potential applications in different fields for PCM with enhanced thermal conductivity are also presented. Finally, we outline the main advances, challenges and outlooks for enhancing the thermal conductivity of PCM.

摘要 : With the rapid development of data-driven human interaction, advanced data-storage technologies with lower power consumption, larger storage capacity, faster switching speed, and higher integration density have become the goals of future memory electronics. Nevertheless, the physical limitations of conventional Si-based binary storage systems lag far behind the ultrahigh-density requirements of post-Moore information storage. In this regard, the pursuit of alternatives and/or supplements to the existing storage technology has come to the forefront. Recently, organic-based resistive memory materials have emerged as promising candidates for next-generation information storage applications, which provide new possibilities of realizing high-performance organic electronics. Herein, the memory device structure, switching types, mechanisms, and recent advances in organic resistive memory materials are reviewed. In particular, their potential of fulfilling multilevel storage is summarized. Besides, the present challenges and future prospects confronted by organic resistive memory materials and devices are discussed.

摘要 : MXenes, as an emerging family of conductive two-dimensional materials, hold promise for late-model electrode materials in Li-ion batteries. A primary challenge hindering the development of MXenes as electrode materials is that a complete understanding of the intrinsic storage mechanism underlying the charge/discharge behavior remains elusive. This article presents two key discoveries: first, the characteristics of the Ti 3 C 2 T x structure can be modified systematically by calcination in various atmospheres, and second, these structural changes greatly affect Li-ion storage behavior, which reveals the mechanism for lithium storage in Ti 3 C 2 T x MXene. Specifically, via ammonization, the interlayer spacing gets dilated and uniform, giving rise to only one redox couple. In stark contrast, there are two well-recognized redox couples corresponding to two interlayer spacings in pristine Ti 3 C 2 T x MXene, in which Li-ion (de)intercalation occurs between interlayers in a sequential manner as evidenced by ex situ X-ray diffraction (XRD). Notably, the XRD diffraction peaks shift hardly in the whole range of charge/discharge voltage, indicating a zero-strain feature upon Li-ion (de)intercalation. Moreover, the diffusion-controlled contribution percentage to capacity inversely depends on the scan rate. The understanding suggests a new design principle of the MXene anode: reduced lateral size to shorten the diffusion path and dilated interlayer spacing.

摘要 : Abstract A simple chemical precipitation method is used to synthesize the cubic phase of ZnS nanoparticles. The crystal structure, phase purity, surface morphology, optical and photo-luminescence properties, and photocatalytic activity of ZnS nanoparticles were studied using X-ray diffraction (XRD), fourier transform infrared (FTIR) spectra, Raman spectrometer, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV–vis spectrophotometer, fluorescence spectrophotometer and 721 spectrophotometer. XRD, FTIR, Raman and XPS analysis indicates that the ZnS nanoparticles has a cubic phase with the cell parameter a = 5.406 Å without the presence of any other impurities. SEM image shows that the average particle size of ZnS nanoparticles is about 40 nm. Optical properties and photoluminescence experiment confirmed that the Eg value is found to be 3.21 eV and the emission spectra are made up of four emission bands at 345, 408, 444 and 510 nm under excitation wavelength at 290 nm. Photocatalytic experiment results indicate that the pure ZnS nanoparticles exhibits an obviously enhanced photocatalytic activity for degradation MO, and MR dyes than degradation MB, and XO dyes due to the ZnS nanoparticles can easily degradation the N N bonds. Based on the electrochemical measurement and photocatalytic experiment, a possible photocatalytic mechanism for degradation of various dyes in presence of the ZnS nanoparticles are analyzed.