Hengyang Normal University

About: Hengyang Normal University is a education organization based out in Hengyang, China. It is known for research contribution in the topics: Graphene & Adsorption. The organization has 1087 authors who have published 1280 publications receiving 13850 citations. The organization is also known as: Hengyang Teachers' College & Héngyáng Shīfàn Xuéyuàn.

Dynamical behavior of a third-order rational fuzzy difference equation

Abstract: According to a generalization of division (g-division) of fuzzy numbers, this paper is concerned with the boundedness, persistence and global behavior of a positive fuzzy solution of the third-order rational fuzzy difference equation $$x_{n+1}=A+\frac{x_{n}}{x_{n-1}x_{n-2}},\quad n=0,1,\ldots, $$ where A and initial values $x_{0}$ , $x_{-1}$ , $x_{-2}$ are positive fuzzy numbers. Moreover, some examples are given to demonstrate the effectiveness of the results obtained.

Putative genes in alkaloid biosynthesis identified in Dendrobium officinale by correlating the contents of major bioactive metabolites with genes expression between Protocorm-like bodies and leaves.

Abstract: Dendrobium officinale, an endangered Chinese herb, possesses extensive therapeutic effects and contains bioactive ingredients such as major polysaccharides, alkaloids, and minimal flavonoids. We first obtained the protocorm-like bodies (PLBs) of this plant through tissue culture in order to determine the distribution of the main secondary metabolites in each organelle and the PLBs. We then analyzed the correlation between gene expression level from comparative transcriptome sequencing and metabolite content in different organs to identify putative genes encoding enzymes involved in the biosynthesis of polysaccharides, alkaloids, and flavonoids. We used seeds as explants for protocorm induction and PLB propagation of D. officinale. The optimal medium formula for PLB propagation was 1/2 MS + α-NAA 0.5 mg·L− 1 + 6-BA 1.0 mg·L− 1 + 2, 4-D 1.5–2.0 mg·L− 1 + potato juice 100 g·L− 1. Stems, PLBs and leaves of D. officinale had the highest content of polysaccharides, alkaloids and flavonoids, respectively. Naringenin was only produced in stem; however, PLBs with high alkaloid content can replace other organs producing alkaloids. The hot water extraction method outperformed the ultrasound-assisted extraction method for extracting polysaccharides from D. officinale. A comparative transcriptome analysis of PLBs and leaves of D. officinale revealed differential expression of genes encoding enzymes involved in polysaccharide, alkaloid and flavonoid biosynthetic pathways. Putative genes encoding enzymes involved in these biosynthetic pathways were identified. Notably, we identified genes encoding the alkaloid biosynthesis enzymes strictosidine β-D-Glucosidase, geissoschizine synthase and vinorine synthase in D. officinale. The identification of candidate genes encoding enzymes involved in metabolite biosynthesis will help to explore and protect this endangered species and facilitate further analysis of the molecular mechanism of secondary metabolite biosynthesis in D. officinale.

Stability and electronic structure of two-dimensional arsenic phosphide monolayer

Abstract: Using first-principles calculations, we investigate the geometric structures, stabilities, electronic structures, and magnetic properties of three kinds of AsP monolayers: blue-phosphorene-like AsP (blue AsP), black-phosphorene-like AsP (black AsP) and puckered AsP. Stability analysis implies a high possibility of fabricating AsP monolayers in experiments. The blue AsP monolayer possesses the most stable structure with an indirect band-gap of 2.52 eV. The blue AsP system is also a good candidate for visible light photocatalytic decomposition of water. The black one is a semiconductor with a direct band gap of 1.53 eV at the Γ point. The puckered AsP monolayer shows the lowest stability and narrowest indirect band gap of 1.38 eV. Both the intrinsic defects of P and As vacancies result in half-metallicity and magnetic semiconductor for blue and black AsP monolayers, respectively. Our results provide useful information to obtain new two dimensional materials for water splitting photocatalysts and spintronic devices.