Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Long-range prediction of fading signals

Abstract: It was previously proposed to adapt several transmission methods, including modulation, power control, channel coding, and antenna diversity to rapidly time variant fading channel conditions. Prediction of the channel coefficients several tens-to-hundreds of symbols ahead is essential to realize these methods in practice. We describe a novel adaptive long-range fading channel prediction algorithm (LRP) and its utilization with adaptive transmission methods. The LRP is validated for standard stationary fading models and tested with measured data and with data produced by our novel realistic physical channel model. Both numerical and simulation results show that long-range prediction makes adaptive transmission techniques feasible for mobile radio channels.

Catalytic Enantioselective Desymmetrization Reactions to All-Carbon Quaternary Stereocenters.

Abstract: This Review summarizes the advances in the construction of all-carbon quaternary stereocenters via catalytic enantioselective desymmetrization of prochiral and meso-compounds, highlights the power and potential of this strategy in the total synthesis of natural products and biologically active compounds, and outlines the synthetic opportunities still available.

Comparative toxicity of several metal oxide nanoparticle aqueous suspensions to Zebrafish (Danio rerio) early developmental stage

Abstract: With the emergence of manufactured nanomaterials, it is urgent to carry out researches on their potential environmental impacts and biological effects To better understand the potential ecotoxicological impacts of metal oxide nanoparticles released to aquatic environments, the zebrafish 96-h embryo-larval bioassay was used to assess and compare the developmental toxicities of nanoscale zinc oxide (nZnO), titanium dioxide (nTiO(2)) and alumina (nAl(2)O(3)) aqueous suspensions Toxicological endpoints such as zebrafish embryos or larvae survival, hatching rate and malformation were noted and described within 96 h of exposure Meanwhile, a comparative experiment with their bulk counterparts (ie, ZnO/bulk, TiO(2)/bulk and Al(2)O(3)/bulk) was conducted to understand the effect of particle size on their toxicities The results showed that: (i) both nZnO and ZnO/bulk aqueous suspensions delayed zebrafish embryo and larva development, decreased their survival and hatching rates, and caused tissue damage The 96-h LC(50) of nZnO and ZnO/bulk aqueous suspensions on the zebrafish survival are 1793 mg/L and 1550 mg/L respectively; and the 84-h EC(50) on the zebrafish embryo hatching rate are 2065 mg/L and 2066 mg/L respectively Serious tissue ulceration was found on zebrafish larvae exposed to nZnO and ZnO/bulk aqueous suspensions (ii) In contrast, neither nTiO(2) and TiO(2)/bulk nor nAl(2)O(3) and Al(2)O(3)/bulk showed any toxicity to zebrafish embryos and larvae under the same experimental condition It revealed that the metal oxide nanoparticles with different chemical composition have different zebrafish developmental toxicities (iii) Exposures of nTiO(2), nZnO and nAl(2)O(3) produced toxic effects on zebrafish embryos and larvae, which was not different from the effects caused by exposing to their bulk counterparts This is the first study about the developmental toxicity of metal oxide nanoparticles, and the results demonstrate that nZnO is very toxic to zebrafish embryos and larvae, which highlights the need to evaluate the potential eco-toxicity of these manufactured nanomaterials (MNMs)

Crystal structure of an avian influenza polymerase PA N reveals an endonuclease active site

Abstract: The heterotrimeric influenza virus polymerase, containing the PA, PB1 and PB2 proteins, catalyses viral RNA replication and transcription in the nucleus of infected cells PB1 holds the polymerase active site and reportedly harbours endonuclease activity, whereas PB2 is responsible for cap binding The PA amino terminus is understood to be the major functional part of the PA protein and has been implicated in several roles, including endonuclease and protease activities as well as viral RNA/complementary RNA promoter binding Here we report the 22 angstrom (A) crystal structure of the N-terminal 197 residues of PA, termed PA(N), from an avian influenza H5N1 virus The PA(N) structure has an alpha/beta architecture and reveals a bound magnesium ion coordinated by a motif similar to the (P)DX(N)(D/E)XK motif characteristic of many endonucleases Structural comparisons and mutagenesis analysis of the motif identified in PA(N) provide further evidence that PA(N) holds an endonuclease active site Furthermore, functional analysis with in vivo ribonucleoprotein reconstitution and direct in vitro endonuclease assays strongly suggest that PA(N) holds the endonuclease active site and has critical roles in endonuclease activity of the influenza virus polymerase, rather than PB1 The high conservation of this endonuclease active site among influenza strains indicates that PA(N) is an important target for the design of new anti-influenza therapeutics