Shanghai University

About: Shanghai University is a education organization based out in Shanghai, Shanghai, China. It is known for research contribution in the topics: Microstructure & Catalysis. The organization has 59583 authors who have published 56840 publications receiving 753549 citations. The organization is also known as: Shànghǎi Dàxué.

Facile synthesis of reduced graphene oxide/hexagonal WO3 nanosheets composites with enhanced H2S sensing properties

Abstract: Reduced graphene oxide/hexagonal WO3 (rGO/h-WO3) nanosheets composites were synthesized through hydrothermal method and post-calcination treatment. The products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N2 adsorption-desorption, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The results showed that two-dimensional (2D) h-WO3 nanosheets with porous structure were attached on rGO to construct 3D rGO/h-WO3 hybrid nanocomposites. This 3D hybrid nanostructure provided many channels for gas diffusion. The fabricated sensor based on 3.8 wt% rGO/h-WO3 composites showed good gas sensing response to H2S. The sensitivity of the sensor was about 168.58 toward 40 ppm H2S, which was 3.7 times higher than that of pure WO3, and the response time was 7 s when exposed to 10 ppm H2S. Moreover, the sensor showed low detection limit (10 ppb), wide linear range and high selectivity to H2S. The improved gas sensing properties of 3.8 wt% rGO/h-WO3 composites may be attributed to the formation of hetero-junctions, good accepting/transporting electrons properties of rGO and effective gas transport channels in 3D hybrid nanostructure.

Analysis of the transcriptome of Panax notoginseng root uncovers putative triterpene saponin-biosynthetic genes and genetic markers.

Abstract: Panax notoginseng (Burk) F.H. Chen is important medicinal plant of the Araliacease family. Triterpene saponins are the bioactive constituents in P. notoginseng. However, available genomic information regarding this plant is limited. Moreover, details of triterpene saponin biosynthesis in the Panax species are largely unknown. Using the 454 pyrosequencing technology, a one-quarter GS FLX titanium run resulted in 188,185 reads with an average length of 410 bases for P. notoginseng root. These reads were processed and assembled by 454 GS De Novo Assembler software into 30,852 unique sequences. A total of 70.2% of unique sequences were annotated by Basic Local Alignment Search Tool (BLAST) similarity searches against public sequence databases. The Kyoto Encyclopedia of Genes and Genomes (KEGG) assignment discovered 41 unique sequences representing 11 genes involved in triterpene saponin backbone biosynthesis in the 454-EST dataset. In particular, the transcript encoding dammarenediol synthase (DS), which is the first committed enzyme in the biosynthetic pathway of major triterpene saponins, is highly expressed in the root of four-year-old P. notoginseng. It is worth emphasizing that the candidate cytochrome P450 (Pn02132 and Pn00158) and UDP-glycosyltransferase (Pn00082) gene most likely to be involved in hydroxylation or glycosylation of aglycones for triterpene saponin biosynthesis were discovered from 174 cytochrome P450s and 242 glycosyltransferases by phylogenetic analysis, respectively. Putative transcription factors were detected in 906 unique sequences, including Myb, homeobox, WRKY, basic helix-loop-helix (bHLH), and other family proteins. Additionally, a total of 2,772 simple sequence repeat (SSR) were identified from 2,361 unique sequences, of which, di-nucleotide motifs were the most abundant motif. This study is the first to present a large-scale EST dataset for P. notoginseng root acquired by next-generation sequencing (NGS) technology. The candidate genes involved in triterpene saponin biosynthesis, including the putative CYP450s and UGTs, were obtained in this study. Additionally, the identification of SSRs provided plenty of genetic makers for molecular breeding and genetics applications in this species. These data will provide information on gene discovery, transcriptional regulation and marker-assisted selection for P. notoginseng. The dataset establishes an important foundation for the study with the purpose of ensuring adequate drug resources for this species.

On the fractional Adams method

Abstract: The generalized Adams-Bashforth-Moulton method, often simply called ''the fractional Adams method'', is a useful numerical algorithm for solving a fractional ordinary differential equation: D"*^@ay(t)=f(t,y(t)),y^(^k^)(0)=y"0^(^k^),k=0,1,...,n-1, where @a>0,[email protected][email protected]@? is the first integer not less than @a, and D"*^@ay(t) is the @ath-order fractional derivative of y(t) in the Caputo sense. Although error analyses for this fractional Adams method have been given for (a) 0 1, [email protected]?C^1^+^@?^@a^@?[0,T], (c) 0 1, [email protected]?C^3(G), there are still some unsolved problems-(i) the error estimates for @[email protected]?(0,1), [email protected]?C^3(G), (ii) the error estimates for @[email protected]?(0,1), [email protected]?C^2(G), (iii) the solution y(t) having some special forms. In this paper, we mainly study the error analyses of the fractional Adams method for the fractional ordinary differential equations for the three cases (i)-(iii). Numerical simulations are also included which are in line with the theoretical analysis.