The Hong Kong Polytechnic University is a public university located in Hung Hom, Hong Kong. The history of PolyU can be traced back to 1937, and it assumed full university status in 1994. It is one of the funded institutions of the territory's University Grants Committee .PolyU has an international faculty and student community and has developed a global network with more than 440 institutions in 47 countries and regions. PolyU offers 220 postgraduate, undergraduate and sub-degree programmes for more than 32,000 students every year. It is the largest UGC-funded tertiary institution in terms of number of students. Wikipedia.
Hong Kong Polytechnic University and McGill University | Date: 2016-10-18
A triazole bridged flavonoid dimer compound library was efficiently constructed via the cycloaddition reaction of a series of flavonoid-containing azides (Az 1-15) and alkynes (Ac 1-17). These triazole bridged flavonoid dimers and their precursor alkyne- and azide-containing flavonoids were screened for their ability to modulate multidrug resistance (MDR) in P-gp-overexpressed cell line (LCC6MDR), MRP1-overexpressed cell line (2008/MRP1) and BCRP-overexpressed cell line (HEK293/R2 and MCF7-MX100). Generally, they displayed very promising MDR reversal activity against P-gp-, MRP1- and BCRP-mediated drug resistance. Moreover, they showed different levels of selectivity for various transporters. Overall, they can be divided into mono-selective, dual-selective and multi-selective modulators for the P-gp, MRP1 and BCRP transporters. The EC_(50 )values for reversing paclitaxel resistance (141-340 nM) of LCC6MDR cells, DOX (78-590 nM) and vincristine (82-550 nM) resistance of 2008/MRP1 cells and topotecan resistance (0.9-135 nM) of HEK293/R2 and MCF7-MX100 cells were at nanomolar range. Importantly, a number of compounds displayed EC_(50 )at or below 10 nM in BCRP-overexpressed cell lines, indicating that these bivalent triazoles more selectively inhibit BCRP transporter than the P-gp and MRP1 transporters. Most of the dimers are notably safe MDR chemosensitizers as indicated by their high therapeutic index values.
Lin P.,Hong Kong Polytechnic University |
Yan F.,Hong Kong Polytechnic University
Advanced Materials | Year: 2012
Organic thin-film transistors (OTFTs) show promising applications in various chemical and biological sensors. The advantages of OTFT-based sensors include high sensitivity, low cost, easy fabrication, flexibility and biocompatibility. In this paper, we review the chemical sensors and biosensors based on two types of OTFTs, including organic field-effect transistors (OFETs) and organic electrochemical transistors (OECTs), mainly focusing on the papers published in the past 10 years. Various types of OTFT-based sensors, including pH, ion, glucose, DNA, enzyme, antibody-antigen, cell-based sensors, dopamine sensor, etc., are classified and described in the paper in sequence. The sensing mechanisms and the detection limits of the devices are described in details. It is expected that OTFTs may have more important applications in chemical and biological sensing with the development of organic electronics. Organic thin-film transistors, including organic field-effect transistors and organic electrochemical transistors, can be used in various types of chemical and biological sensors, such as pH, humidity, ion, glucose, DNA, enzyme, antibody-antigen, cell and dopamine sensors. The organic transistors are expected to have more important sensing applications with the development of organic electronics. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
So C.M.,Hong Kong Polytechnic University |
Kwong F.Y.,Hong Kong Polytechnic University
Chemical Society Reviews | Year: 2011
Palladium-catalyzed cross-coupling reactions are state-of-the art methods for synthesis of many important compounds. The development of the use of the phenol-derived sulfonated hydroxyl group in the coupling reactions is highly attractive as the hydroxyl group is commonly present in organic compounds and they are versatile alternatives to aryl halides in cross-coupling reactions. In this tutorial review, we summarize the current development of palladium-catalyzed cross-coupling reactions of aryl mesylates. © 2011 The Royal Society of Chemistry.
Huang K.,Hong Kong Polytechnic University
IEEE Transactions on Information Theory | Year: 2013
Designing mobiles to harvest ambient energy such as kinetic activities or electromagnetic radiation will enable wireless networks to be self-sustaining. In this paper, the spatial throughput of a mobile ad hoc network powered by energy harvesting is analyzed using a stochastic-geometry model. In this model, transmitters are distributed as a Poisson point process and energy arrives at each transmitter randomly with a uniform average rate called the energy arrival rate. Upon harvesting sufficient energy, each transmitter transmits with fixed power to an intended receiver under an outage-probability constraint for a target signal-to-interference-and-noise ratio. It is assumed that transmitters store energy in batteries with infinite capacity. By applying the random-walk theory, the probability that a transmitter transmits, called the transmission probability, is proved to be equal to the smaller of one and the ratio between the energy-arrival rate and transmission power. This result and tools from stochastic geometry are applied to maximize the network throughput for a given energy-arrival rate by optimizing transmission power. The maximum network throughput is shown to be proportional to the optimal transmission probability, which is equal to one if the transmitter density is below a derived function of the energy-arrival rate or otherwise is smaller than one and solves a given polynomial equation. Last, the limits of the maximum network throughput are obtained for the extreme cases of high energy-arrival rates and sparse/dense networks. © 1963-2012 IEEE.
Chen X.,Hong Kong Polytechnic University
Mathematical Programming | Year: 2012
We consider a class of smoothing methods for minimization problems where the feasible set is convex but the objective function is not convex, not differentiable and perhaps not even locally Lipschitz at the solutions. Such optimization problems arise from wide applications including image restoration, signal reconstruction, variable selection, optimal control, stochastic equilibrium and spherical approximations. In this paper, we focus on smoothing methods for solving such optimization problems, which use the structure of the minimization problems and composition of smoothing functions for the plus function (x)+.Many existing optimization algorithms and codes can be used in the inner iteration of the smoothing methods. We present properties of the smoothing functions and the gradient consistency of subdifferential associated with a smoothing function. Moreover, we describe how to update the smoothing parameter in the outer iteration of the smoothing methods to guarantee convergence of the smoothing methods to a stationary point of the original minimization problem. © Springer and Mathematical Optimization Society 2012.
Yao Z.-P.,Hong Kong Polytechnic University
Mass Spectrometry Reviews | Year: 2012
Proteins play important roles in living systems and are topics of many fundamental and applied research projects. With the introduction of electrospray ionization and matrix-assisted laser desorption/ionization for analysis of biomacromolecules in the late 1980s, mass spectrometry has become an important tool for characterization of proteins. Characterization of proteins in raw samples by these mass spectrometric techniques, however, usually requires extensive sample pretreatment. Ambient ionization techniques are new mass spectrometric techniques that allow direct analysis of samples with no or little sample preparation. Can these techniques facilitate or even eliminate sample preparation for mass spectrometric analysis of proteins? Apart from sample preparation, do these techniques offer any new features for characterization of proteins as compared with conventional ESI or MALDI? Recent advances in characterization of proteins by ambient mass spectrometry are summarized and commented in this article. © 2011 Wiley Periodicals, Inc.
Choi T.-M.,Hong Kong Polytechnic University
Computers and Operations Research | Year: 2013
Carbon emission tax is an important measure for sustainable supply chain management. This paper studies an optimal supplier selection problem in the fashion apparel supply chain in the presence of carbon emission tax. We consider the scenario in which there are multiple suppliers in the market. In the basic model, each supplier offers a supply lead time and a wholesale pricing contract to the fashion retail buyer. For the fashion retail buyer, the supplier which offers a shorter lead time allows it to postpone the ordering decision with updated and better forecast, and also a smaller carbon tax. However, the wholesale price is usually larger. We propose a two-phase optimal supplier selection scheme in which phase one filters the inferior suppliers and phase two helps to select the best supplier among the set of non-inferior suppliers by multi-stage stochastic dynamic programming. The impacts brought by different formats of carbon emission tax are explored. Finally, we examine an extended model in which there is a local supplier who offers a buyback contract and accepts product returns. Insights from the analysis are discussed. © 2013 Elsevier Ltd.
Hong Kong Polytechnic University | Date: 2016-08-25
A dye-sensitized solar cell that includes an electrode having a semiconductor nanoparticle layer dispersed on a transparent conductive substrate, a plurality of semiconductor nanofibers dispersed on the nanoparticle layer, a first light absorption material is attached to the plurality of semiconductor nanofibers in which the first light absorption material having a first light absorption bandwidth, and a second light absorption material deposited on the light absorption material of the plurality of semiconductor nanofibers, the second light absorption material having a second light absorption bandwidth complementary to the first light absorption bandwidth, a counter electrode includes a metal-coated transparent conductive substrate, and an electrolyte in contact with the near-infrared light absorption material and the counter electrode.
Hong Kong Polytechnic University | Date: 2016-01-28
A method for retarding or reversing progression of myopia of a viewer includes providing an object in front of the viewer; providing a transparent layer between the viewer and the object; and providing a primary image on the transparent layer, the transparent layer allows the viewer to see the object as a secondary image simultaneously with the primary image, wherein the secondary image is focused in front of the central region of the retina. A method for reducing hyperopia of a viewer includes providing an object in front of the viewer to provide a primary image; providing a transparent layer between the viewer and the object; providing a secondary image on the transparent layer, the transparent layer allows the viewer to see the primary image simultaneously with the secondary image, wherein the secondary image is focused behind the central region of the retina. Other systems are also described herein.
Hong Kong Polytechnic University | Date: 2016-03-23
This invention provides a catalyst comprising a new form of ZnFe_(2)O_(4 )spinel nanoparticles, and a method for preparing same. The catalyst is useful for catalyzing the esterification of fatty acids or transesterification of triglycerides, wherein the reaction rate and conversion can be enhanced by free fatty acids.