Metal support effects in electrocatalysis at hexagonal boron nitride

A scanning electrochemical droplet cell technique has been employed to screen the intrinsic electrocatalytic hydrogen evolution reaction (HER) activity of hexagonal boron nitride (h-BN) nanosheets supported on different metal substrates (Cu and Au). Local (spatially-resolved) voltammetry and Tafel analysis reveal that electronic interaction with the underlying metal substrate plays a significant role in modulating the electrocatalytic activity of h-BN, with Au-supported h-BN exhibiting significantly enhanced HER charge-transfer kinetics (exchange current is ca. two orders of magnitude larger) compared to Cu-supported h-BN, making the former material the superior support in a catalytic sense

Characterization of lncRNA–miRNA–mRNA Network to Reveal Potential Functional ceRNAs in Bovine Skeletal Muscle

There is growing evidence that non-coding RNAs are emerging as critical regulators of skeletal muscle development. In order to reveal their functional roles and regulatory mechanisms, we constructed a lncRNA–miRNA–mRNA network according to the ceRNA (competitive endogenous RNA) theory, using our high-throughput sequencing data. Subsequently, the network analysis, GO (Gene Ontology) analysis, and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis were performed for functional annotation and exploration of lncRNA ceRNAs. The results uncovered a scale-free characteristics network which exhibited high functional specificity for bovine skeletal muscle development: co-expression lncRNAs were significantly enriched in muscle development related biological processes and the Wnt signaling pathway. Furthermore, GSEA (Gene Set Enrichment Analysis) indicated that the risk score has a tendency to associate with myogenesis, and differentially expressed RNAs were validated by qPCR, further confirming the credibility of our network. In summary, this study provides insights into lncRNA-mediated ceRNA function and mechanisms in bovine skeletal muscle development and will expand our understanding of lncRNA biology in mammals

A trehalose biosynthetic enzyme doubles as an osmotic stress sensor to regulate bacterial morphogenesis

The dissacharide trehalose is an important intracellular osmoprotectant and the OtsA/B pathway is the principal pathway for trehalose biosynthesis in a wide range of bacterial species. Scaffolding proteins and other cytoskeletal elements play an essential role in morphogenetic processes in bacteria. Here we describe how OtsA, in addition to its role in trehalose biosynthesis, functions as an osmotic stress sensor to regulate cell morphology in Arthrobacter strain A3. In response to osmotic stress, this and other Arthrobacter species undergo a transition from bacillary to myceloid growth. An otsA null mutant exhibits constitutive myceloid growth. Osmotic stress leads to a depletion of trehalose-6-phosphate, the product of the OtsA enzyme, and experimental depletion of this metabolite also leads to constitutive myceloid growth independent of OtsA function. In vitro analyses indicate that OtsA can self-assemble into protein networks, promoted by trehalose-6-phosphate, a property that is not shared by the equivalent enzyme from E. coli, despite the latter's enzymatic activity when expressed in Arthrobacter. This, and the localization of the protein in non-stressed cells at the mid-cell and poles, indicates that OtsA from Arthrobacter likely functions as a cytoskeletal element regulating cell morphology. Recruiting a biosynthetic enzyme for this morphogenetic function represents an intriguing adaptation in bacteria that can survive in extreme environments

Analysis of ground states of fcc thin film of binary alloy under confinement

In this paper, we have investigated the ground states of a few-layered fcc thin film of binary alloy with two surfaces in the (001) direction under symmetric surface confinement. The phase diagram of the ground states is given according to the energy analysis of binary alloy thin film composed of six atomic layers in the (001) direction. Surface confinement field (SC field) is introduced as a term to describe the confinement on the two surfaces in the (001) direction. Using Monte Carlo simulation, we have found that there are 17 different ground states occurring when both SC field and chemical potential vary from $-\infty$ to $+\infty$. Antiphase boundary(APB) was found in 12 of the 17 ground states, and only nine configurations with different symmetry were found among the 17 ground states

Size-Dependent Structural Properties of a High-Nb TiAl Alloy Powder

TiAl-based alloys are promising light weight structural materials for high temperature applications in the field of aerospace. Recently, fabrication technologies starting from powders including powder metallurgy and additive manufacturing have been developed to overcome the difficulties in the processing, machining and shaping of TiAl-based alloys. Spherical alloy powders with different particle size distributions are usually used in these fabrication techniques. The purpose of this study is to reveal the size-dependent structural properties of a high-Nb TiAl powder for these fabrication technologies starting from powders. A high-Nb TiAl pre-alloyed powder with nominal composition of Ti-48Al-2Cr-8Nb (at. %) was prepared by the electrode induction melting gas atomization (EIGA) method. The phase structure and morphology of the as-atomized powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The size-dependent structural changes of the as-atomized powders with different sizes were studied by differential scanning calorimetry (DSC) and in situ high temperature XRD. It was found that with decreasing the powder size, the content of the γ-TiAl phase decreases and the α2-Ti3Al phase increases. The α2-Ti3Al to γ-TiAl phase transformation was found in the temperature range of 600–770 °C. Based on the present work, the structural characteristics of TiAl powders are strongly dependent on their particle size, which should be considered in optimizing the process parameters of TiAl alloys fabricated from powders

Research on spatial structure of regional tourism resources——Taking Nanjing city as an example

The spatial structure of tourism resources can help to understand the spatial distribution characteristics of tourism resources,and then guide the tourism planning and improve the competitive advantage of tourism area.Based on the relevant data released by Jiangsu Provincial Tourism Bureau,taking advantage of the ArcGIS platform,the development and utilization of tourism resources and the problems in the spatial structure of tourism resources were analyzed by using the superiority index,Nearest Neighbor Index and Traffic Connectivity Index.The results show that:1) the spatial distribution of tourism resources in Nanjing is clustered;the distribution of the main urban area is relatively dense,and the resource level is higher;2) the spatial distribution of the traffic network between the tourist resources is in the middle and lower levels,and the traffic loops are poor and the accessibility is not high.The accessibility degree shows ‘center high,four weeks low’ and ‘east and west high,north and south low’.3)The resource of Nanjing tourism can be optimized by optimization of the transport network;by determining the core of tourism,clarifying the level of scenic spots;increasing the efforts of tourism development and developing tourism products in depth;integration of the tourism resources,construction of the clusters and zones of tourism resources;and other aspects