Tunable Synthesis of SiC/SiO2 Heterojunctions via Temperature Modulation

A large-scale production of necklace-like SiC/SiO2 heterojunctions was obtained by a molten salt-mediated chemical vapor reaction technique without a metallic catalyst or flowing gas. The effect of the firing temperature on the evolution of the phase composition, microstructure, and morphology of the SiC/SiO2 heterojunctions was studied. The necklace-like SiC/SiO2 nanochains, several centimeters in length, were composed of SiC/SiO2 core-shell chains and amorphous SiO2 beans. The morphologies of the as-prepared products could be tuned by adjusting the firing temperature. In fact, the diameter of the SiO2 beans decreased, whereas the diameter of the SiC fibers and the thickness of the SiO2 shell increased as the temperature increased. The growth mechanism of the necklace-like structure was controlled by the vapor-solid growth procedure and the modulation procedure via a molten salt-mediated chemical vapor reaction process

Influence of the Halogenated Substituent on Charge Transfer Mobility of Aniline Tetramer and Derivatives: Remarkable Anisotropic Mobilities

The halogen-substituted derivatives and the parent aniline tetramer as organic semiconductors have been theoretically investigated with a focus on the electronic properties and charge transport properties through density functional theory and Marcus Hush theory methods. The study on the transport properties of holes and electrons can obtain insight into the effect of halogenation substitution on injection of charge carriers and transport character. The equilibrium geometries, reorganization energies, frontier molecular orbitals, intermolecular electronic couplings, electrostatic potential isosurfaces, and angular resolution anisotropic mobilities were calculated. The calculated results revealed that perfluorination and perchlorination can induce stronger structure relaxation and effectively lower the highest occupied molecular orbital and lowest unoccupied molecular orbital levels. The angle dependence mobilities of the three crystals show remarkable anisotropic character. The carrier mobility curves for both electron and hole transport of the parent aniline tetramer and halogen-substituted derivatives all show a remarkable anisotropic feature. Furthermore, the ANIH and ANIC1 crystals show higher electron-transfer mobilities than hole-transfer mobilities and, hence perform better as an n-type organic semiconductor. The ANIH crystal possesses a low reorganization energy combined with a high electronic coupling and electron-transfer mobility, which indicates that the ANIH crystal might be a more ideal candidate as an n-type organic semiconductor material

Waypoint Graph Based Fast Pathfinding in Dynamic Environment

Pathfinding is a fundamental task in many applications including robotics, computer games, and vehicle navigation. Waypoint graph is often used for pathfinding due to its advantage in specifying the space and obstacles in a region. Currently the waypoint graph based pathfinding suffers from large computation overhead and hence long latency in dynamic environment, where the location of obstacles may change. In this paper, we propose a fast approach for waypoint graph based pathfinding in such scenario. We eliminate unnecessary waypoints and edges to make the graph sparse. And then we design a prediction-based local method to handle the dynamic change in the environment. Extensive simulation has been done and the results show that the proposed approach outperforms existing approaches

Genome-Wide Identification of bHLH Transcription Factor Family in Malus sieversii and Functional Exploration of MsbHLH155.1 Gene under Valsa Canker Infection

Xinjiang wild apple (Malus sieversii) is an ancient relic; a plant with abundant genetic diversity and disease resistance. Several transcription factors were studied in response to different biotic and abiotic stresses on the wild apple. Basic/helix–loop–helix (bHLH) is a large plant transcription factor family that plays important roles in plant responses to various biotic and abiotic stresses and has been extensively studied in several plants. However, no study has yet been conducted on the bHLH gene in M. sieversii. Based on the genome of M. sieversii, 184 putative MsbHLH genes were identified, and their physicochemical properties were studied. MsbHLH covered 23 subfamilies and lacked two subfamily genes of Arabidopsis thaliana based on the widely used classification method. Moreover, MsbHLH exon–intron structures matched subfamily classification, as evidenced by the analysis of their protein motifs. The analysis of cis-acting elements revealed that many MsbHLH genes share stress- and hormone-related cis-regulatory elements. These MsbHLH transcription factors were found to be involved in plant defense responses based on the protein–protein interactions among the differentially expressed MsbHLHs. Furthermore, 94 MsbHLH genes were differentially expressed in response to pathogenic bacteria. The qRT-PCR results also showed differential expression of MsbHLH genes. To further verify the gene function of bHLH, our study used the transient transformation method to obtain the overexpressed MsbHLH155.1 transgenic plants and inoculated them. Under Valsa canker infection, the lesion phenotype and physiological and biochemical indexes indicated that the antioxidant capacity of plants could increase and reduce the damage caused by membrane peroxidation. This study provides detailed insights into the classification, gene structure, motifs, chromosome distribution, and gene expression of bHLH genes in M. sieversii and lays a foundation for a better understanding disease resistance in plants, as well as providing candidate genes for the development of M. sieversii resistance breeding

Rational Design of a Profluorescent Substrate for S‑adenosylhomocysteine Hydrolase and its Applications in Bioimaging and Inhibitor Screening

S-Adenosylhomocysteine hydrolase (SAHase) is a cellular enzyme that plays a key role in the methylation process, and a potential drug target in the discovery of antiviral and anticancer agents. There is increasing interest in determining its activity in the biological and clinical fields with chemosensors but with limited success so far. Herein, we designed and developed for the first time an off/on-type of fluorogenic substrate (NADE) that is directly responsive to SAHase activity. NADE used 1,8-naphthalimide as the signal reporter and adenosine (Ade) as the reaction center; removal of the Ade moiety enhanced the fluorescence by >10-fold. Kinetic study showed that NADE followed a non-Michaelis–Menten pattern that corresponded to the allosteric behavior of SAHase. NADE showed excellent selectivity and functioned efficiently in cells, allowing the microscopic imaging of SAHase activity. NADE can also be used to identify and measure the effectiveness of inhibitors in a markedly superior way. In a word, NADE would be broadly useful in clinical applications and academic studies