Showing papers by "University of Macau published in 2012"
TL;DR: In this article, the role of the dark side of leadership in employee creativity is examined, by examining how and when department leader abusive supervision may flow down organizational levels to unbalance creativity.
Abstract: This research sheds light on the role of the dark side of leadership in employee creativity by examining how and when department leader abusive supervision may flow down organizational levels to un...
532 citations
TL;DR: A systematic review of communication/netsworking technologies in Smart Grid is conducted, including communication/networking architecture, different communication technologies that would be employed into this architecture, quality of service (QoS), optimizing utilization of assets, control and management, etc.
488 citations
TL;DR: Seven PM formulations of anti-tumor drugs being evaluated in clinical trials are reviewed in this paper, in terms of formulation study, in vitro cytotoxicity, in vivo pharmacokinetics, anti-Tumor efficacy and safety as well as clinical trials, to shed new light on the discovery of novel PM formulations.
483 citations
TL;DR: Based on the information in the literature that is summarized in this paper, the use of alkaloids as anticancer agents is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloid properties can be made.
Abstract: Alkaloids are important chemical compounds that serve as a rich reservoir for drug discovery. Several alkaloids isolated from natural herbs exhibit antiproliferation and antimetastasis effects on various types of cancers both in vitro and in vivo. Alkaloids, such as camptothecin and vinblastine, have already been successfully developed into anticancer drugs. This paper focuses on the naturally derived alkaloids with prospective anticancer properties, such as berberine, evodiamine, matrine, piperine, sanguinarine, and tetrandrine, and summarizes the mechanisms of action of these compounds. Based on the information in the literature that is summarized in this paper, the use of alkaloids as anticancer agents is very promising, but more research and clinical trials are necessary before final recommendations on specific alkaloids can be made.
320 citations
TL;DR: Luminescent metal complexes have attracted increasing attention in the literature over the last few decades as discussed by the authors, and transition metal compounds have been widely studied for luminescent sensing applications due to their attractive photophysical properties.
256 citations
TL;DR: In this article, the authors analyzed the work performance of salespeople with a competitive disposition and found a positive link between dispositional competitiveness and discretionary performance, and suggest that salespeople's affective commitment to their organization mediates this link.
255 citations
18 Jun 2012
TL;DR: This paper mainly analyzes existing authentication and access control methods, and then, it designs a feasible one for the Internet of Things.
Abstract: Due to the inherent vulnerabilities of the Internet, security and privacy issues should be considered and addressed before the Internet of Things is widely deployed. This paper mainly analyzes existing authentication and access control methods, and then, it designs a feasible one for the Internet of Things.
248 citations
TL;DR: The anti-cancer activity of terpenoids appears promising and will potentially open more opportunities for cancer therapy, however, current studies are restricted to descriptive findings and lack mechanistic insights and systematic structure–activity relationship (SAR) studies.
Abstract: Introduction: Terpenoids constitute the largest class of natural products and are a rich reservoir of candidate compounds for drug discovery. Recent efforts into the research and development of anti-cancer drugs derived from natural products have led to the identification of a variety of terpenoids that inhibit cancer cell proliferation and metastasis via various mechanisms. Despite the increasing number of research reports, there lacks a comprehensive review of anti-cancer activity of terpenoids. Areas covered: The present article provides an overview of the recent progress in the anti-cancer studies on terpenoids. Over a dozen naturally originated terpenoid compounds, in particular those derived from traditional Chinese medicine, were classified into five categories according to the structures, namely monoterpenoids, sesquiterpenoids, diterpenoids, triterpenoids and tetraterpenoids. The anti-cancer activities and relevant mechanistic insights of these compounds are discussed in this review. Expert opini...
236 citations
TL;DR: Herb pairs have played, and may continue to play a key role in full investigation of general herb compatibility for their indispensable position in TCM, and much more research is needed for the standardization, safety evaluation, and mechanism exploration of herb pairs.
234 citations
TL;DR: This study compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009 to discuss the possible reasons and proposed the rational strategies for drug research and development in the future.
Abstract: Summarizing the status of drugs in the market and examining the trend of drug research and development is important in drug discovery. In this study, we compared the drug targets and the market sales of the new molecular entities approved by the U.S. Food and Drug Administration from January 2000 to December 2009. Two networks, namely, the target–target and drug–drug networks, have been set up using the network analysis tools. The multi-target drugs have much more potential, as shown by the network visualization and the market trends. We discussed the possible reasons and proposed the rational strategies for drug research and development in the future.
227 citations
TL;DR: The fractional diffusion equation is discretized by the implicit finite difference scheme with the shifted Grunwald formula and the coefficient matrix possesses the Toeplitz-like structure and a multigrid method is proposed to solve the resulting system.
TL;DR: This work formulate the decomposition problem as the minimization of a quadratic function which incorporates both the retinex constraint and the nonlocal texture constraint, and can be solved in closed form with the standard conjugate gradient algorithm.
Abstract: We propose a method for intrinsic image decomposition based on retinex theory and texture analysis. While most previous methods approach this problem by analyzing local gradient properties, our technique additionally identifies distant pixels with the same reflectance through texture analysis, and uses these nonlocal reflectance constraints to significantly reduce ambiguity in decomposition. We formulate the decomposition problem as the minimization of a quadratic function which incorporates both the retinex constraint and our nonlocal texture constraint. This optimization can be solved in closed form with the standard conjugate gradient algorithm. Extensive experimentation with comparisons to previous techniques validate our method in terms of both decomposition accuracy and runtime efficiency.
26 Nov 2012
TL;DR: This paper proposes a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA) that imitates the way wolves search for food and survive by avoiding their enemies.
Abstract: In computer science, a computational challenge exists in finding a globally optimized solution from a tremendously large search space. Heuristic optimization methods have therefore been created that can search the very large spaces of candidate solutions. These methods have been extensively studied in the past, and progressively extended in order to suit a wide range of optimization problems. Researchers recently have invented a collection of heuristic optimization methods inspired by the movements of animals and insects (e.g., Firefly, Cuckoos, Bats and Accelerated PSO) with the advantages of efficient computation and easy implementation. This paper proposes a new bio-inspired heuristic optimization algorithm called the Wolf Search Algorithm (WSA) that imitates the way wolves search for food and survive by avoiding their enemies. The contribution of the paper is twofold: 1. for verifying the efficacy of the WSA the algorithm is tested quantitatively and compared to other heuristic algorithms under a range of popular non-convex functions used as performance test problems for optimization algorithms; 2. The WSA is investigated with respective to its memory requirement. Superior results are observed in most tests.
TL;DR: An enhanced model-predictive control (EMPC) scheme is presented for positioning control of a novel parallel-kinematic XY micropositioning system, which has a motion range larger than 10 mm along with a compact structure.
Abstract: Flexure-based micropositioning systems with a large workspace are attractive for a variety of precision engineering applications. In this paper, a new idea of multistage compound parallelogram flexure is proposed for the mechanism design of a novel parallel-kinematic XY micropositioning system, which has a motion range larger than 10 mm along with a compact structure. The established quantitative models and the stage performances are validated by conducting finite-element analysis (FEA) and experimental studies. Moreover, an enhanced model-predictive control (EMPC) is presented for positioning control of the system, which has a nonminimum-phase plant. It is shown that the EMPC is capable of producing a low magnitude of output tracking error by imposing an appropriate suppression on the control effort. Simulation and experimental studies reveal that the EMPC scheme outperforms the conventional proportional-integral-derivative (PID) and MPC methods in terms of transient response speed and steady-state accuracy. The idea that is presented in this paper is extendable to design and control of other micro-/nanopositioning systems with either minimum- or nonminimum-phase plants.
TL;DR: In this article, the authors examined the relationship between procedural justice and employee job insecurity, and the boundary conditions of this relationship, and hypothesized that procedural justice is negatively related to job insecurity and that this relationship is moderated by ethical leadership.
Abstract: This study examines the relationship between procedural justice and employee job insecurity, and the boundary conditions of this relationship. Drawing upon uncertainty management theory and ethical leadership research, we hypothesized that procedural justice is negatively related to job insecurity, and that this relationship is moderated by ethical leadership. We further predicted that the moderating relationship would be more pronounced among employees with a low power distance orientation. We tested our hypotheses using a sample of 381 workers in Macau and Southern China. The results support all of our hypotheses. The implications of these results for research and practice are discussed.
TL;DR: Experimental results showed that the participants were able to learn to increase the relative amplitude in individual alpha band during NFT and short term memory performance was significantly enhanced by 20 sessions of NFT.
TL;DR: It was found that education level, age and household income were the significant factors affecting residents' WTP, and most residents were still willing to hand their e-waste into the government for centralized collection.
TL;DR: In this article, an adaptive dc-link voltage-controlled LC coupling hybrid active power filter (LC-HAPF) for reducing switching loss and switching noise under reactive power compensation is presented.
Abstract: This paper presents a novel adaptive dc-link voltage-controlled LC coupling hybrid active power filter (LC-HAPF) for reducing switching loss and switching noise under reactive power compensation. First, the mathematical relationship between LC-HAPF dc-link voltage and reactive power compensation range is deduced and presented. Based on the compensation range analysis, the required minimum dc-link voltage with respect to different loading reactive power is deduced. Then, an adaptive dc-link voltage controller for the three-phase four-wire LC-HAPF is proposed, in which the dc-link voltage as well as the reactive power compensation range can be adaptively changed according to different inductive loading situations. Therefore, the compensation range, switching loss, and switching noise of the LC-HAPF can be determined and reduced correspondingly. In this paper, the reference dc-link voltage is classified into certain levels for selection in order to alleviate the problem of dc voltage fluctuation caused by its reference frequent variation, and hence reducing the fluctuation impact on the compensation performances. Finally, representative simulation and experimental results of a three-phase four-wire center-split LC -HAPF are presented to verify the validity and effectiveness of the proposed adaptive dc-link voltage-controlled LC-HAPF in dynamic reactive power compensation.
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TL;DR: In this paper, the authors argue that the generally observed positive effect of technological collaboration on product innovation may be diluted in highly competitive markets, and that the interactive effect of technology collaboration and market competition will be further moderated by sectoral technological intensity.
Abstract: Drawing on the strategic alliances and innovation literature, this study proposes that the impact of technological collaboration on product innovation is contingent on market competition and sectoral technology characteristics. Specifically, it argues that the generally observed positive effect of technological collaboration on product innovation may be diluted in highly competitive markets, and the interactive effect of technological collaboration and market competition on product innovation will be further moderated by sectoral technological intensity. Data on the product innovation and technological collaboration of 944 Chinese firms across five manufacturing sectors provide robust support for the contingent effects of technological collaboration on product innovation.
TL;DR: This review aims to systematically summarize and analyze the anti-cancer properties of terpenoids, the main components of essential oils in Rhizoma Curcumae, and thus enable the development of new anti- cancer drugs.
TL;DR: This paper presents a novel compliant parallel XY micromotion stage driven by piezoelectric actuators (PZT) designed using a symmetric 4-PP structure in which double four-bar flexure is chosen as the prismatic joint.
Abstract: This paper presents a novel compliant parallel XY micromotion stage driven by piezoelectric actuators (PZT). With the purpose to obtain complete kinematic decoupling and good stiffness performance, the stage is designed using a symmetric 4-PP structure in which double four-bar flexure is chosen as the prismatic joint. Matrix method is employed to establish the compliance model of the mechanism. Based on the model, dynamic analysis is investigated after static analysis is carried out. The dimensions of the mechanism are optimized using the particle swarm optimization (PSO) algorithm in order to maximize the natural frequencies. Finite-element analysis (FEA) result indicates that the mechanism has an almost linear force-deflection relationship, high first natural frequency (720.52 Hz), and ideal decoupling property. To cope with the nonlinearities such as hysteresis that exists in the PZT, the control system is constructed by a proportional-integral-derivative (PID) feedback controller with a feedforward compensator based on Preisach model. The fabricated prototype has a 19.2 μm × 8.8 μm rectangular workspace with coupling less than 5%. The result of the closed-loop test shows that the XY stage can achieve positioning, tracking and contouring tasks with small errors.
TL;DR: In this paper, the authors examined the important role of the servicescape in relation to customers' cognitive (beliefs about servicescape quality), affective (affect and satisfaction) and behavioral responses (desire to stay) in the context of convention and exhibition centers in Macao.
TL;DR: In this paper, the authors argue that the generally observed positive effect of technological collaboration on product innovation may be diluted in highly competitive markets, and that the interactive effect of technology collaboration and market competition will be further moderated by sectoral technological intensity.
TL;DR: Experimental results show that both LS-SVM and RVM model-based control schemes can suppress the rate-dependent hysteresis to a negligible level, which validates the feasibility and effectiveness of the proposed approaches.
Abstract: Hysteresis nonlinearity degrades the positioning accuracy of a piezostage and requires a suppression for precision micro-/nanopositioning applications. This paper proposes two new approaches to modeling and compensating the rate-dependent hysteresis of a piezostage driven by piezoelectric stack actuators. By formulating the hysteresis modeling as an online nonlinear regression problem, online least squares support vector machine (SVM) (LS-SVM) and online relevance vector machine (RVM) models are proposed to capture the hysteretic behavior. Both hysteresis models are capable of updating continually with subsequent samples. After a comparative study on modeling performances, an inverse model-based feedforward combined with proportional-integral-derivative feedback control is presented to alleviate the hysteresis effect. Experimental results show that the LS-SVM model-based control scheme is over 86% more accurate than the RVM model-based one in the motion tracking task, whereas the latter is 14 times faster than the former in terms of updating time. Moreover, both LS-SVM and RVM model-based control schemes can suppress the rate-dependent hysteresis to a negligible level, which validates the feasibility and effectiveness of the proposed approaches.
TL;DR: To fully exploit the potential of PCHM in cancer therapy, more attentions are advocated to be focused on their safety evaluation and mechanism exploration.
TL;DR: A cyclometalated iridium(III) biquinoline complex targets the protein-protein interface of the tumor necrosis factor-α (TNF-α) trimer and displays comparable in vitro potency to the strongest small-molecule inhibitor of TNF- α.
Abstract: Staying in the pocket: A cyclometalated iridium(III) biquinoline complex targets the protein-protein interface (see picture; C yellow, N blue, Ir dark green) of the tumor necrosis factor-α (TNF-α) trimer. Molecular-modeling studies confirm the nature of this interaction. Both enantiomers of the iridium complex display comparable in vitro potency to the strongest small-molecule inhibitor of TNF-α.
TL;DR: Results indicate that baicalein prevented PC12 cells from 6-OHDA-induced oxidative damage via the activation of Keap1/Nrf2/HO-1, and it also involves the PKCα and PI3K/AKT signaling pathway.
Abstract: Baicalein, one of the major flavonoids found in Scutellaria baicalensis Georgi, displays neuroprotective effects on experimental models of Parkinson's disease (PD) in vitro and in vivo. Although the antioxidative and/or anti-inflammatory activity of baicalein likely contributes to these neuroprotective effects, other modes of action remain largely uncharacterized. In the present study, baicalein pretreatment significantly prevented cells from 6-hydroxydopamine (6-OHDA)-induced damage by attenuating cellular apoptosis. However, post-treatment with baicalein did not show any restorative effect against 6-OHDA-induced cellular damage. We found that baicalein increased transcriptional factor NF-E2-related factor 2 (Nrf2)/hemo oxygenase 1(HO-1) protein expression and decreased Kelch-like ECH-associated protein 1 (Keap1) in a time- and concentration-dependent manner in PC12 cells. In addition, baicalein induced Nrf2 nuclear translocation and enhanced antioxidant response element (ARE) transcriptional activity, which conferred cytoprotection against 6-OHDA-induced oxidative injury. Moreover, we demonstrated that cytoprotective effects of baicalein could be attenuated by Nrf2 siRNA transfection and the HO-1 inhibitor zinc protoporphyrin (Znpp) as well as the proteasome inhibitor MG132. Furthermore, PKCα and AKT protein phosphorylation were up-regulated by baicalein pretreatment, and selective inhibitors targeted to PKC, PI3K, and AKT could block the cytoprotective effects of baicalein. Taken together, our results indicate that baicalein prevented PC12 cells from 6-OHDA-induced oxidative damage via the activation of Keap1/Nrf2/HO-1, and it also involves the PKCα and PI3K/AKT signaling pathway. Ultimately, the neuroprotective effects of baicalein may endue baicalein as a promising candidate for the prevention of PD.
TL;DR: SSa and SSd showed potent anti-inflammatory activity through inhibitory effects on NF-κB activation and thereby on iNOS, COX-2 and pro-inflammatory cytokines.
TL;DR: Li et al. as mentioned in this paper empirically examined some listed Chinese firms' political connection, ownership, and financing constraints and found that politically connected firms display no financing constraints whereas firms without connection experience significant constraints.
17 Apr 2012
TL;DR: The authors' evaluation data show that novel false data injection attacks against the energy routing process can effectively disrupt the effectiveness of energy distribution process, causing significant supplied energy loss, energy transmission cost and the number of outage users.
Abstract: Smart Grid is a new type of energy-based cyber physical system (CPS) that will provide reliable, secure, and efficient energy transmission and distribution. The way to secure the distributed energy routing process that efficiently utilizes the distributed energy resources and minimizes the energy transmission overhead is essential in smart grid. In this paper, we study the vulnerability of the distributed energy routing process and investigate novel false data injection attacks against the energy routing process. We consider several general attacks, in which the adversary may manipulate the quantity of energy supply, the quantity of energy response, and the link state of energy transmission. The forged data injected by those attacks will cause imbalanced demand and supply, increase the cost for energy distribution, and disrupt the energy distribution. We formally model these attacks and quantitatively analyze their impact on energy distribution. Our evaluation data show that those attacks can effectively disrupt the effectiveness of energy distribution process, causing significant supplied energy loss, energy transmission cost and the number of outage users.