Hong Kong Baptist University

About: Hong Kong Baptist University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Population & China. The organization has 7811 authors who have published 18919 publications receiving 555274 citations. The organization is also known as: Hong Kong Baptist College & HKBU.

Detection of nicking endonuclease activity using a G-quadruplex-selective luminescent switch-on probe

Abstract: A series of luminescent Ir(III) complexes were synthesised and evaluated for their ability to act as G-quadruplex-selective probes. A novel Ir(III) complex was found to be highly selective for G-quadruplex DNA, and was employed in a label-free G-quadruplex-based detection assay for nicking endonuclease activity in aqueous solution. A proof-of-concept of this probe has been demonstrated by using Nb·BbvCI as a model enzyme. In this assay, a DNA substrate comprised of oligonucleotides ON1 (5′-GTG3TAG3CG3T2G2CTGAG2TGA-3′) and ON2 (5′-TCAC2TCAGC2A2C2-3′) initially exists in a duplex conformation, resulting in a low luminescence signal due to the weak interaction between the Ir(III) complex and duplex DNA. Upon cleavage by Nb·BbvCI, the guanine-rich sequence is released and folds into a G-quadruplex, which greatly enhances the luminescence of the Ir(III) probe. This method was highly sensitive for Nb·BbvCI over other DNA-modifying enzymes.

Percolation threshold determines the optimal population density for public cooperation.

Abstract: While worldwide census data provide statistical evidence that firmly link the population density with several indicators of social welfare, the precise mechanisms underlying these observations are largely unknown Here we study the impact of population density on the evolution of public cooperation in structured populations and find that the optimal density is uniquely related to the percolation threshold of the host graph irrespective of its topological details We explain our observations by showing that spatial reciprocity peaks in the vicinity of the percolation threshold, when the emergence of a giant cooperative cluster is hindered neither by vacancy nor by invading defectors, thus discovering an intuitive yet universal law that links the population density with social prosperity

A sensitive AgNPs/CuO nanofibers non-enzymatic glucose sensor based on electrospinning technology

Abstract: A novel sensitive non-enzymatic glucose sensor was fabricated with silver nanoparticles modified cupric oxide nanofibers (Ag/CuO NFs). The Ag/CuO NFs–indium tin oxide (ITO) electrode was prepared by firstly electrospinning AgNO 3 , Cu(NO 3 ) 2 and polyvinylpyrrolidone onto the surface of an ITO glass and followed with oxidization to Ag/CuO NFs by annealing in air. The Ag/CuO NFs–ITO electrode was applied to detect glucose by cyclic voltammetry (CV) and chronoamperometry. The effects of electrospinning time, AgNO 3 :Cu(NO 3 ) 2 mass ratio, calcination temperature and NaOH concentration on the sensitivity of glucose sensor were investigated in detail. Under the optimal conditions, CV and chronoamperometric studies revealed that, compared with CuO NFs–ITO electrode, the AgNPs modification showed a remarkable increase in the efficiency of the electro-catalytic oxidation of glucose, exhibiting a high sensitivity of 1347 μA mM −1 cm −2 and a low detection limit of 51.7 nM ( S / N = 3). More importantly, the poisoning by chloride ion and the interferences from l -ascorbic acid, uric acid, lactose, sucrose, fructose, and dopamine were negligible. The Ag/CuO NFs–ITO sensor could be used for detecting glucose in real samples. This Ag/CuO NFs–ITO sensor is highly promising for non-enzymatic glucose sensing attributing to its high sensitivity, fast response, excellent stability and good reproducibility.

Label-free luminescence switch-on detection of hepatitis C virus NS3 helicase activity using a G-quadruplex-selective probe

Abstract: A series of luminescent Ir(III) complexes were synthesised and evaluated for their ability to act as luminescent G-quadruplex-selective probes. The Ir(III) complex 9, [Ir(phq)2(phen)]PF6 (where phq = 2-phenylquinoline; phen = 1,10-phenanthroline), exhibited high luminescence in the presence of G-quadruplex DNA compared to dsDNA and ssDNA, and was employed to construct a label-free G-quadruplex-based assay for hepatitis C virus NS3 helicase activity in aqueous solution. Moreover, the application of the assay for screening potential helicase inhibitors was demonstrated. To our knowledge, this is the first G-quadruplex-based assay for helicase activity.

Variations and changes of annual precipitation in Central Asia over the last century

Abstract: This study examines the temporal variations and spatial distributions of annual precipitation over Central Asia during the periods of 1901–2013, 1951–2013, and 1979–2013 using the latest version of Global Precipitation Climatology Centre (GPCC) full data reanalysis version 7 (GPCC V7) data set. The linear trend and multiperiods of the precipitation over the entire region and plain and mountainous area separately are analysed by linear least square method and ensemble empirical mode decomposition method. An overall increasing trend [0.66 mm (10 years)−1] is found for the entire region during 1901–2013, which is smaller than that of 1951–2013. The regional annual precipitation exhibits multi-decadal variations, with a sharp decline during 1901–1944, followed by an increase until 1980s, and a fluctuation thereafter. During 1979–2013, the mountainous area shows a greater increasing trend than the entire region. Furthermore, the regional annual precipitation has exhibited high-frequency variations with 3-year and 6-year quasiperiods and a low-frequency variation with 28-year quasiperiods. In terms of the spatial distribution, increasing trend in the annual precipitation is found in Xinjiang and decreasing trends appear over the five countries of Central Asia during 1951–2013. Empirical orthogonal function results show that the mountainous area is the large variability centre of the annual precipitation. The dominant mode of interannual variability in Central Asia annual precipitation is related to El Nino-Southern Oscillation, which explains about 17% of the interannual variance during 1951–2013. The results of this study describe the long-term variation in the annual precipitation over Central Asia as well as its relationship with some key climate indices in great detail, which will benefit the understanding and the prediction of the climate variations in this region.