A topological classification for piecewise monotone iterative roots

It is proved that every continuous iterative root of a piecewise monotone function with finite nonmonotonicity height, is an extension from a root on the c     

Integral representations for the Lagrange polynomials,Shively’s pseudo-Laguerre polynomials,and the generalized Bessel polynomials

Motivated essentially by their potential for applications in the mathematical, physical, and statistical sciences, the object of this paper is to investigate several general families of hypergeometric polynomials and their associated multiple integral representations. By suitably specializing the main results presented here, the corresponding integral representations are derived for familiar simpler classes of hypergeometric polynomials such as (for example) the Lagrange polynomials, Shively’s pseudo-Laguerre polynomials, and generalized Bessel polynomials. Each of the integral representations derived in this paper may be also viewed as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials.     

不同大气信道对大气激光通信的影响研究

对自由空间光通信技术的基本原理进行了分析,并对该项技术目前所存在的关键问题一自由空间衰减效应做了重点研究,为实现不同天气条件下语音信号的传输进行了初步探索。     

Inducing new secondary metabolites through co-cultivation of the fungus Pestalotiopsis sp. with the bacterium Bacillus subtilis

Two new lactones, pestalotiolactones A (1) and B (2), together with three known compounds (3–5) were isolated from the axenic culture of the endophytic fungus Pestalotiopsis sp., obtained from fruits of Drepanocarpus lunatus (Fabaceae). Co-culture of this fungus with Bacillus subtilis afforded two new sesquiterpenoids pestabacillins A (6) and B (7) as well as eight known compounds (8–15). Their structures were elucidated by extensive analysis of the NMR and MS data as well as by comparison with literature data. All isolated compounds were evaluated for their cytotoxic and antimicrobial activities but proved to be inactive.     

Activity Essential Residue Analysis of Taxoid 10β-O-Acetyl Transferase for Enzymatic Synthesis of Baccatin

Taxoid 10β-O-acetyl transferase (DBAT) is a key enzyme in the biosynthesis of the famous anticancer drug paclitaxel, which catalyses the formation of baccatin III from 10-deacetylbaccatin III (10-DAB). However, the activity essential residues of the enzyme are still unknown, and the acylation mechanism from its natural substrate 10-deacetylbaccatin III and acetyl CoA to baccatin III remains unclear. In this study, the homology modelling, molecular docking, site-directed mutagenesis, and kinetic parameter determination of the enzyme were carried out. The results showed that the enzyme mutant DBAT^H162A resulted in complete loss of enzymatic activity, suggesting that the residue histidine at 162 was essential to DBAT activity. Residues D166 and R363 which were located in the pocket of the enzyme by homology modelling and molecular docking were also important for DBAT activity through the site-directed mutations. Furthermore, four amino acid residues including S31 and D34 from motif SXXD, D372 and G376 from motif DFGWG also played important roles on acylation. This was the first report of the elucidation of the activity essential residues of DBAT, making it possible for the further structural-based re-design of the enzyme for efficient biotransformation of baccatin III and paclitaxel.     

Exonuclease-assisted multicolor aptasensor for visual detection of ochratoxin A based on G-quadruplex-hemin DNAzyme-mediated etching of gold nanorod

Microchimica Acta - The authors report on a microneedle-based amperometric nonenzymatic glucose sensor for painless and continuous monitoring of glucose. It consists of 3 × 5 sharp...