Oligothiophene molecular wires at graphene-based molecular junctions.

The use of graphene as a new type of electrode at molecular junctions has led to a renewal of molecular electronics. Indeed, the symmetry breaking induced by the graphene electrode yields different electronic behaviors at the molecular junction and in particular enhanced conductance for longer molecules. In this respect, several studies involving different molecular backbones and anchoring groups have been performed. Here in the same line, we consider oligopthiophene based hybrid gold-graphene junctions and we measure their electrical properties using the STM-I(s) method in order to determine their attenuation factor and the effect of specific anchoring groups. The results are supported by density functional theory (DFT) calculations, and exhibit a similar behavior to what is observed at alkane-based junctions.

Charge transport in hybrid platinum/molecule/graphene single molecule junctions.

The single molecule conductance of hybrid platinum/alkanedithiol/graphene junctions has been investigated with a focus on understanding the influence of employing two very different contact types. We call this an "anti-symmetric" configuration, with the two different contacts here being platinum and graphene, which respectively provide very different electronic coupling to the alkanedithiol bridge. The conductance of these junctions is experimentally investigated by using a non-contact scanning tunneling microscopy (STM) based method called the I(s) technique. These experimental determinations are supported by density functional theory (DFT) calculations. These alkanedithiol bridging molecules conduct electric current through the highest occupied molecular orbital (HOMO), and junctions formed with Pt/graphene electrode pairs are slightly more conductive than those formed with Au/graphene electrodes which we previously investigated. This is consistent with the lower work function of gold than that of platinum. The measured conductance decays exponentially with the length of the molecular bridge with a low tunneling decay constant, which has a similar value for Pt/graphene and Au/graphene electrode pairs, respectively. These new results underline the importance of the coupling asymmetry between the two electrodes, more than the type of the metal electrode itself. Importantly, the tunneling decay constant is much lower than that of alkanedithiols with the symmetrical equivalent, i.e. identical metal electrodes. We attribute this difference to the relatively weak van der Waals coupling at the graphene interface and the strong bond dipole at the Pt-S interface, resulting in a decrease in the potential barrier at the interface.

Improving Stock Closing Price Prediction Using Recurrent Neural Network and Technical Indicators.

This study focuses on predicting stock closing prices by using recurrent neural networks (RNNs). A long short-term memory (LSTM) model, a type of RNN coupled with stock basic trading data and technical indicators, is introduced as a novel method to predict the closing price of the stock market. We realize dimension reduction for the technical indicators by conducting principal component analysis (PCA). To train the model, some optimization strategies are followed, including adaptive moment estimation (Adam) and Glorot uniform initialization. Case studies are conducted on Standard & Poor's 500, NASDAQ, and Apple (AAPL). Plenty of comparison experiments are performed using a series of evaluation criteria to evaluate this model. Accurate prediction of stock market is considered an extremely challenging task because of the noisy environment and high volatility associated with the external factors. We hope the methodology we propose advances the research for analyzing and predicting stock time series. As the results of experiments suggest, the proposed model achieves a good level of fitness.

Coupling effects of nitrate reduction and sulfur oxidation in a subtropical marine mangrove ecosystem with Spartina alterniflora invasion.

The mangrove ecosystem has a high nitrate reduction capacity, which significantly alleviates severe nitrogen pollution. However, current research on nitrate reduction mechanisms in the mangrove ecosystem is limited. Furthermore, Spartina alterniflora invasion has disrupted the balance of the mangrove ecosystem and the effect of S. alterniflora on nitrate reduction has not yet been fully elucidated. Nitrate reduction was comprehensively investigated in a subtropical mangrove ecosystem in this study, which has been invaded by S. alterniflora for 40 years. Results showed that S. alterniflora significantly increased the relative and absolute abundance of nitrate reduction genes, especially nirS (nitrite reductase), in the mangrove ecosystem. Dissimilatory nitrate reduction to ammonium was the main pathway of nitrate reduction in the mangrove ecosystem. Nitrate reduction was mainly performed by Desulfobacterales and occurred in the shallow layers (0-10 cm) of mangrove sediments. A strong positive correlation was found between nitrate reduction and sulfur oxidation (especially sulfide oxidation), and the sulfide content was significantly positively correlated with the relative abundance of nitrate reduction genes. Moreover, 207 metagenomic assembled genomes (MAGs) were constructed, including 50 MAGs with high numbers (≥ 10) of nitrate reduction genes. This finding indicates that the dominant microbes had strong nitrate reduction potential in mangrove sediments. Our findings highlight the impact of S. alterniflora invasion on nitrate reduction in a subtropical marine mangrove ecosystem. This study provides new insights into our understanding of nitrogen pollution control and contributes to the exploration of new nitrogen-degrading microbes in mangrove ecosystems.

Sulfur metabolism in subtropical marine mangrove sediments fundamentally differs from other habitats as revealed by SMDB.

Shotgun metagenome sequencing provides the opportunity to recover underexplored rare populations and identify difficult-to-elucidate biochemical pathways. However, information on sulfur genes, including their sequences, is scattered in public databases. Here, we introduce SMDB ( https://smdb.gxu.edu.cn/ )-a manually curated database of sulfur genes based on an in-depth review of the scientific literature and orthology database. The SMDB contained a total of 175 genes and covered 11 sulfur metabolism processes with 395,737 representative sequences affiliated with 110 phyla and 2340 genera of bacteria/archaea. The SMDB was applied to characterize the sulfur cycle from five habitats and compared the microbial diversity of mangrove sediments with that of other habitats. The structure and composition of microorganism communities and sulfur genes were significantly different among the five habitats. Our results show that microorganism alpha diversity in mangrove sediments was significantly higher than in other habitats. Genes involved in dissimilatory sulfate reduction were abundant in subtropical marine mangroves and deep-sea sediments. The neutral community model results showed that microbial dispersal was higher in the marine mangrove ecosystem than in others habitats. The Flavilitoribacter of sulfur-metabolizing microorganism becomes a reliable biomarker in the five habitats. SMDB will assist researchers to analyze genes of sulfur cycle from the metagenomic efficiently.

Complete mitochondrial genome and the phylogenetic position of the Sphaeroma sp. (Crustacea, Isopod, Sphaeromatidae).

The complete mitogenome of Sphaeroma sp. (Crustacea, Isopod, Sphaeromatidae) was determined in this study. The total length of mitogenome was 15,839 bp, and contained 13 protein-coding genes, 21 tRNA genes, 2 rRNA genes, 1 control region, and 2 unknown fragments which longer than 200 bp. The nucleotide composition was 25.80% A, 16.56% C, 25.94% G and 31.67% T. Six initiation codons (ATA, ATC, ATG, ATT, ACG, GTG) and three termination codons (TAA, TAG, TA-) were used in the protein-coding genes. The length of tRNA genes ranged from 52 to 65 bp, and tRNA-Arg was not identified. The phylogenetic result showed Sphaeroma sp. was closely related to Sphaeroma terebrans with high bootstrap value supported.

Mitochondrial genome of the ringstraked guitarfish Rhinobatos hynnicephalus (Elasmobranchii: Rajiformes).

The complete mitochondrial genome of the ringstraked guitarfish Rhinobatos hynnicephalus is firstly presented in this study, which is also the first representative in the family Rhinobatidae. It is 16,776 bp in length and contains 37 genes and one control region as the typical gene arrangement and transcriptional direction in vertebrates. The overall base composition is 31.7% A, 26.8% C, 13.5% G and 28.1% T. The 22 tRNA genes ranged from 67 bp (tRNA-Ser2) to 75 bp (tRNA-Leu1). The origin of L-strand replication (OL) sequence was identified between tRNA-Asn and tRNA-Cys genes. The termination associated sequence (TAS) and the conserved sequence blocks (CSB 1--3) were recognized in the control region.