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The University of Hong Kong is the oldest tertiary institution in Hong Kong. Its motto is "Sapientia et Virtus" in Latin, meaning "wisdom and virtue", and "明德格物" in Chinese. The medium of instruction in most classes is English. The school adopts the problem-based learning teaching strategy which aims to train students' problem solving skills. It has a great achievement in Humanities, Legal subjects, Political science, Biological science and Medicine. Wikipedia.

Observational studies usually show that moderate alcohol use is associated with better cognitive function. Such studies are vulnerable to residual confounding arising from systematic differences between moderate alcohol users and others. A Mendelian randomization study carried out in a suitable population, such as southern Chinese men, in which alcohol use is low to moderate and is influenced by genotype, offers an alternative and superior approach for clarifying the causal effect of moderate alcohol use on cognitive function. The authors used aldehyde dehydrogenase 2 (ALDH2) genotype (AA, GA, or GG) as an instrumental variable in 2-stage least squares analysis to obtain unbiased estimates of the relation of alcohol consumption (measured in alcohol units (10 g ethanol) per day) with cognitive function, assessed from delayed 10-word recall score (n = 4,707) and Mini-Mental State Examination (MMSE) score (n = 2,284), among men from the Guangzhou Biobank Cohort Study (2003-2008). ALHD2 genotype was strongly associated with alcohol consumption, with an F statistic of 71.0 in 2-stage least squares analysis. Alcohol consumption was not associated with delayed 10-word recall score (-0.03 words per alcohol unit, 95% confidence interval:-0.18, 0.13) or MMSE score (0.06 points per alcohol unit, 95% confidence interval:-0.22, 0.34). Moderate alcohol use is unlikely to be cognitively protective. © The Author 2012. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved.

Ng F.Y.,University of Hong Kong
Journal of orthopaedic surgery (Hong Kong) | Year: 2012

To compare total knee arthroplasty (TKA) patients who received continuous femoral nerve block (FNB) with local anaesthetics through a catheter versus patient-controlled analgesia (PCA) with intravenous morphine. 50 women and 10 men aged 51 to 84 years with matched characteristics underwent TKA and received either continuous FNB with local anaesthetics through a catheter (n=30) or PCA with intravenous morphine (n=30). None of the patients had had previous knee surgery. All operations were performed according to the standard protocol. Daily mean pain numerical rating scale at rest (NRS-R) and during movement (NRS-M), requirement of extra pain control, complications related to pain control, and overall patient satisfaction in both groups were compared. Both groups were similar in terms of pain NRS-R and NRS-M, overall satisfaction, and length of hospital stay. Within each group, pain NRS-M score was significantly higher than pain NRS-R score. In the FNB group, 3 patients had dislodgement of the femoral catheter on day 1 and switched to PCA with intravenous morphine. Two of them had fair satisfaction. Patients in the PCA group had significantly more side-effects (nausea, vomiting, dizziness, and pruritis); 2 of the 5 patients with nausea and vomiting had fair satisfaction. No patients had any surgical complication. Both FNC and PCA provide reliable pain control.

The origin of the catalytic power of enzymes with a meta-stable native state, e.g. molten globular state, is an unsolved challenging issue in biochemistry. To help understand the possible differences between this special class of enzymes and the typical ones, we report here computer simulations of the catalysis of both the well-folded wild-type and the molten globular mutant of chorismate mutase. Using the ab initio quantum mechanical/molecular mechanical minimum free-energy path method, we determined the height of reaction barriers that are in good agreement with experimental measurements. Enzyme-substrate interactions were analyzed in detail to identify factors contributing to catalysis. Computed angular order parameters of backbone N-H bonds and side-chain methyl groups suggested site-specific, non-uniform rigidity changes of the enzymes during catalysis. The change of conformational entropy from the ground state to the transition state revealed distinctly contrasting entropy/enthalpy compensations in the dimeric wild-type enzyme and its molten globular monomeric variant. A unique catalytic strategy was suggested for enzymes that are natively molten globules: some may possess large conformational flexibility to provide strong electrostatic interactions to stabilize the transition state of the substrate and compensate for the entropy loss in the transition state. The equilibrium conformational dynamics in the reactant state were analyzed to quantify their contributions to the structural transitions enzymes needed to reach the transition states. The results suggest that large-scale conformational dynamics make important catalytic contributions to sampling conformational regions in favor of binding the transition state of substrate. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg.

Fu Z.,Shanxi University | Huang L.,Shanxi University | Meng Z.,Shanxi University | Wang P.,Shanxi University | And 5 more authors.
Nature Physics | Year: 2014

The search for topological superconductors is a challenging task. One of the most promising directions is to use spin-orbit coupling through which an s-wave superconductor can induce unconventional p-wave pairing in a spin-polarized metal. Recently, synthetic spin-orbit couplings have been realized in cold-atom systems where instead of a proximity effect, s-wave pairing originates from a resonant coupling between s-wave molecules and itinerant atoms. Here we demonstrate a dynamic process in which spin-orbit coupling coherently produces s-wave Feshbach molecules from a fully polarized Fermi gas, and induces a coherent oscillation between these two. This demonstrates experimentally that spin-orbit coupling does coherently couple singlet and triplet states, and implies that the bound pairs of this system have a triplet p-wave component, which can become a topological superfluid by further cooling to condensation and confinement to one dimension. © 2014 Macmillan Publishers Limited.

Yeo S.I.,University of Hong Kong
International journal of rheumatic diseases | Year: 2013

Gout is a common condition which is mainly treated with the hypo-uricemic agent, allopurinol. Although allopurinol is generally a well-tolerated drug, there is a small risk of developing potentially fatal complications, such as allopurinol hypersensitivity syndrome. Recent advances in pharmacogenomics have made possible the identification of genes which confer susceptibility to specific drugs. A recent multi-national case-control study has reported allopurinol as the most common drug associated with Stevens-Johnson syndrome and toxic epidermal necrolysis. Several studies have established a strong association between the human leukocyte antigen (HLA)-B*5801 gene and development of Stevens-Johnson syndrome and toxic epidermal necrolysis. The allele frequency of HLA-B*5801 is highest in the South East Asian population.Since other hypo-uricemic agents are available, patients may wish to have HLA-B*5801 testing before being started on allopurinol. As the test for HLA-B*5801 is expensive, time-consuming and only available in selected laboratories, there is a need to evaluate the utility and cost-effectiveness of this test in our region. © 2013 The Author International Journal of Rheumatic Diseases © 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Rowell C.,Hong Kong University of Science and Technology | Lam E.Y.,University of Hong Kong
IEEE Transactions on Antennas and Propagation | Year: 2012

The performance characteristics of the capacitive slot, or a slot placed between the feed and ground connections, in a planar inverted-F antenna (PIFA) are comprehensively analyzed. The PIFA capacitive slot behavior is measured inside a two antenna system within a mobile phone where the first antenna is a multiple band PIFA and the second antenna is a higher frequency band PIFA directly overlapping with the first antenna higher frequency band. The dual band PIFA in this paper is designed to be resonant in the quad-band GSM+3G/4G, and the second PIFA is resonant in the 3G/4G frequency bands. The capacitive slot has three types of behaviors: affect the matching of existing frequency resonances, induce another frequency resonance, and improve the isolation between the two antennas. Together with optimal antenna ground and feed placement, the capacitive slot can act as a notched bandstop filter to decrease the S 21 mutual coupling between the two antennas by over 20 dB and decrease the envelope correlation by almost one order of magnitude. © 1963-2012 IEEE.

Rowell C.,ASTRI Hong Kong | Lam E.Y.,University of Hong Kong
IEEE Antennas and Propagation Magazine | Year: 2012

This paper is a survey of internal antennas in mobile phones from 1997 to 2010. It covers almost 60 GSM and 3G handsets, ranging from the first GSM handset with an internal antenna to the current Nokia, Sony-Ericsson, Motorola, and Apple handsets. The paper discusses different types of mobile-phone antennas, feeding structures, active antennas, isolation, and antenna loading techniques. This paper examines different design techniques for mobile-phone antennas, and the limitations of antenna design due to manufacturing technologies and the effect of handset materials. Antenna performance parameters, including S parameters, radiation efficiency, SAR, and TRP/TIS are reported for the surveyed handsets. The effective antenna volume for every antenna is calculated, in order to determine the average volume/space required for each antenna type and the corresponding performance. Some of the handsets are further simulated using commercial electromagnetic simulators to illustrate the electromagnetic-field distributions. This paper summarizes the antenna design parameters as a function of handset performance, and presents a short summary of design procedure. © 2011 IEEE.

Yu Z.,Tsinghua University | Thywissen J.H.,University of Toronto | Zhang S.,University of Hong Kong
Physical Review Letters | Year: 2015

We investigate the properties of a spinless Fermi gas close to a p-wave interaction resonance. We show that the effects of interaction near a p-wave resonance are captured by two contacts, which are related to the variation of energy with the p-wave scattering volume v and with the effective range R in two adiabatic theorems. Exact pressure and virial relations are derived. We show how the two contacts determine the leading and subleading asymptotic behavior of the momentum distribution (∼1/k2 and ∼1/k4) and how they can be measured experimentally by radio-frequency and photoassociation spectroscopies. Finally, we evaluate the two contacts at high temperature with a virial expansion. © 2015 American Physical Society.

Sims L.D.,Asia Pacific Veterinary Information Services | Peiris M.,University of Hong Kong
Current Topics in Microbiology and Immunology | Year: 2013

The occurrence of avian influenza A(H5N1) in Hong Kong in 1997 led to the development of a "One-Health" approach to deal with emerging infectious diseases that has been applied to other emergent diseases such as SARS and the pandemic H1N1 2009. Evaluation of poultry marketing and production systems and investigations at the animal-human interface, led to defining the routes of human exposure to avian influenza and factors that allowed virus to multiply and persist. Active and systematic surveillance of apparently healthy as well as diseased poultry and wild birds provided evidence of ongoing virus evolution in the wider region. Epidemiological studies, supplemented with molecular epidemiology, helped to elucidate the role of the poultry marketing system and live poultry markets in the persistence of avian influenza viruses and provided evidence for the impact of interventions designed to interrupt virus transmission. Enhanced bio-security, active surveillance together with targeted and evidence-based interventions in the poultry production, and marketing system together with poultry vaccination has prevented further human H5N1 disease and minimized outbreaks of poultry disease in Hong Kong. Similar strategies have led to the understanding of the emergence of SARS and provided options for preventing the re-emergence of this disease. Surveillance of influenza in swine has provided insights into the emergence of the 2009 pandemic, to the reverse zoonosis of the pandemic virus from humans to swine and to the emergence of novel reassortant viruses within swine. "One Health" strategies are not "cost-free" and require sensitive implementation to optimize food-safety and food security, while safeguarding the economics of animal husbandry and the environment and remaining sensitive to cultural practices. © Springer-Verlag Berlin Heidelberg 2013.

Kong T.S.K.,University of Hong Kong
British Journal of Criminology | Year: 2016

Commercial sex is a risky business and men who buy sex engage in a form of voluntary risky behaviour. Using Stephen Lyng's notion of edgework, this qualitative study examines Hong Kong men who buy sex in Hong Kong/China and argues that these men's engagement can be understood as a form of leisure edgework which balances risk and pleasure by negotiating the boundary between order and chaos. This article concludes that men buying sex can be seen as a form of resistance to normative companionate sexuality and the skills they exercise are key cultural principles needed in late-modern society. Edgework therefore plays an important role in modern intimacy, especially in shaping masculinity and men's sexual scripts. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Centre for Crime and Justice Studies (ISTD). All rights reserved.

Wang A.Y.-M.,University of Hong Kong
Seminars in Dialysis | Year: 2012

Dialysis patients suffer a greatly heightened risk of cardiovascular morbidity and mortality. These patients also experience an extremely high prevalence of left ventricular hypertrophy, heart failure, and coronary artery disease. Thus, there is a clinical need to identify circulating biomarkers that have diagnostic value for cardiovascular disease and have prognostic importance so to facilitate earlier and more aggressive intervention. The natriuretic peptides, namely brain natriuretic peptide (BNP) or N-terminal pro-brain natriuretic peptide (NT-pro-BNP), belong to a family of vasopeptide hormones that are released from the heart and play a major role in blood pressure regulation and volume homeostasis through their direct effects on the kidney and systemic vasculature and represent a favorable aspect of neurohumoral activation. Testing for BNP or NT-pro-BNP has recently emerged as important diagnostic tool for heart failure and a useful biomarker for risk stratification in the general population. In dialysis patients, there has been interest in evaluating the potential of BNP and NT-pro-BNP as markers of volume status as they are frequently elevated in dialysis patients. However, the interpretation of their levels is confounded by impaired renal clearance and preexisting LV abnormalities which have limited their applicability as a surrogate marker of volume status. In this article, we discuss the pathophysiology accounting for the elevation of natriuretic peptides in dialysis patients and review current evidence that supports their clinical utility as a diagnostic and prognostic tool in this population. © 2012 Wiley Periodicals, Inc.

Artificial turf can develop unusually high surface temperature on hot sunny days. Solar and terrestrial radiant energy regimes as key determinants of thermal performance deserve detailed investigation. This study evaluated six components of the radiant-energy environment of a natural turf (NT) and a contiguous artificial turf (AT) sports fields in Hong Kong: direct solar, reflected solar, net solar, sky thermal, ground thermal, and net thermal. Temperature was monitored at five positions: air at 150 cm, 50 cm and 15 cm height, turf surface, and substrate. The experiment included four replications, namely two summer sunny days, and two duplicated instrument sets at each turf site. The two sites reacted very differently to the same intense daily sum of solar radiation input of 23.70 MW m-2 with 9 h of bright sunshine (>120 W m-2), and daily sum of sky thermal radiation input of 38.59 MW m-2. The maximum direct solar radiation reached 976.1 W m-2 at 1245 h. NT albedo of 0.23 vis-à-vis AT of merely 0.073, and higher moisture content and specific heat of NT materials, presented critical differences. The hydrophobic and generally dry plastic (polyethylene) pile-fibers and black rubber-granule infill materials have low specific heat. Intense incoming shortwave and longwave radiation absorbed readily by AT materials raised turf surface temperature to 70.2 °C and substrate 69.3 °C, in comparison with <40 °C at NT. A cascading warming effect was triggered, beginning with low albedo, high net solar irradiance and low material specific heat, leading to heated AT materials, high ground-thermal radiation, and heat flux to near-ground air by conduction and convection. The ephemeral rainfall cooling confirmed ineffective cooling by irrigation. Athletes are immersed in an anomalously intense and omnidirectional radiant-energy and sensible-heat ambience. The heat-stress health implications of AT for athletes in hot summer afternoon call for preventive-precautionary measures and re-assessment of NT-to-AT decisions. © 2016 Elsevier Ltd.

Cowling B.J.,University of Hong Kong
Nature communications | Year: 2013

Influenza A viruses are believed to spread between humans through contact, large respiratory droplets and small particle droplet nuclei (aerosols), but the relative importance of each of these modes of transmission is unclear. Volunteer studies suggest that infections via aerosol transmission may have a higher risk of febrile illness. Here we apply a mathematical model to data from randomized controlled trials of hand hygiene and surgical face masks in Hong Kong and Bangkok households. In these particular environments, inferences on the relative importance of modes of transmission are facilitated by information on the timing of secondary infections and apparent differences in clinical presentation of secondary infections resulting from aerosol transmission. We find that aerosol transmission accounts for approximately half of all transmission events. This implies that measures to reduce transmission by contact or large droplets may not be sufficient to control influenza A virus transmission in households.

Li S.Y.W.,University of Hong Kong | Magrabi F.,University of New South Wales | Coiera E.,University of New South Wales
Journal of the American Medical Informatics Association | Year: 2012

Objective: To understand the complex effects of interruption in healthcare. Materials and methods: As interruptions have been well studied in other domains, the authors undertook a systematic review of experimental studies in psychology and humanecomputer interaction to identify the task types and variables influencing interruption effects. Results: 63 studies were identified from 812 articles retrieved by systematic searches. On the basis of interruption profiles for generic tasks, it was found that clinical tasks can be distinguished into three broad types: procedural, problem-solving, and decision-making. Twelve experimental variables that influence interruption effects were identified. Of these, six are the most important, based on the number of studies and because of their centrality to interruption effects, including working memory load, interruption position, similarity, modality, handling strategies, and practice effect. The variables are explained by three main theoretical frameworks: the activation-based goal memory model, prospective memory, and multiple resource theory. Discussion: This review provides a useful starting point for a more comprehensive examination of interruptions potentially leading to an improved understanding about the impact of this phenomenon on patient safety and task efficiency. The authors provide some recommendations to counter interruption effects. Conclusion: The effects of interruption are the outcome of a complex set of variables and should not be considered as uniformly predictable or bad. The task types, variables, and theories should help us better to identify which clinical tasks and contexts are most susceptible and assist in the design of information systems and processes that are resilient to interruption.

Jim C.Y.,University of Hong Kong
Urban Ecosystems | Year: 2014

Hong Kong's rugged topography demands creation of developable land by reclaiming the harbor and terracing hillslopes. The vertical faces between adjoining hillslope-platforms are often stabilized by stone retaining walls. Such artificial cliffs embedded in the urban matrix, as a habitat analogue of rocky cliffs, have been colonized by spontaneous-ruderal vegetation. Detailed field assessment of 289 walls with 793 trees permitted in-depth analysis of this unique tropical urban ecology to inform conservation. The 28 stonewall tree species, mainly native, are dominated by six keystone and companion Ficus (Moraceae) species. They can develop into large cliff hangers > 20 m height on the apparently precarious and inhospitable walls. The many joints between masonry blocks provide opportunities for lodging and germination of seeds brought by frugivorous birds and bats. The aft-soil behind walls provides catchment for normal root functions. Beginning as pioneers and persisting as climax members, they short-circuit the seral processes. Wall-gripping capability as large epilithic woody hemi-epiphytes is due to the strangler-fig habit, an evolutionary trait that originated in the tropical forest. The polymorphic roots with morphological plasticity and self-grafting ability, and their multiple modes of interactions with wall niches, account for firm attachment on the vertical habitat and exploration of proximal soils. A model of strangler-fig growth on stone walls serving as surrogate host tree is developed. The diverse and versatile rooting modes are the basis to sustain strangler-fig wall conditions to permit continuation of strangler-fig habit. Such unique nature-in-city and natural-cum-cultural gems deserve conservation as urban ecological heritage. © 2013 Springer Science+Business Media New York.

Cheung V.Y.T.,University of Hong Kong
Journal of Minimally Invasive Gynecology | Year: 2015

The objective of this study was to determine the outcome of using ultrasound-guided local methotrexate injection as the first-line treatment of cesarean scar pregnancy (CSP). A literature review was performed on all eligible reports using this modality as the first-line treatment of CSP. Relevant publications were obtained from the PubMed electronic database from inception to December 2014. Ninety-six cases from 95 women reported in 17 articles were reviewed. The success rate was 73.9% after a single local methotrexate injection. An accumulated success rate of 88.5% could be achieved after additional local or intramuscular methotrexate administration. Eleven cases (11.5%) failed methotrexate treatment and required surgical interventions. Except for women with serum human chorionic gonadotropin levels higher than 100 000 IU/L, ultrasound-guided local methotrexate injection could be considered as a first-line treatment modality for CSP. © 2015 AAGL.

Ellobody E.,Tanta University | Young B.,University of Hong Kong
Journal of Constructional Steel Research | Year: 2011

This paper investigates the behaviour of pin-ended axially loaded concrete encased steel composite columns. A nonlinear 3-D finite element model was developed to analyse the inelastic behaviour of steel, concrete, longitudinal and transverse reinforcement bars as well as the effect of concrete confinement of the concrete encased steel composite columns. The interface between the steel section and concrete, the longitudinal and transverse reinforcement bars, and the reinforcement bars and concrete were also considered that allowed the bond behaviour to be modeled and the different components to retain their profile during the deformation of the column. Furthermore, the initial overall (out-of-straightness) geometric imperfection was carefully incorporated in the model. The finite element model has been validated against published experimental results. The main objective of the study was to understand the structural response and modes of failure of the columns and to assess the composite column strengths against current design codes. The study covered slender, non-slender, stub and long concrete encased steel composite columns. The concrete strengths varied from normal to high strength (20110 MPa). The steel section yield stresses also varied from normal to high strength (275690 MPa). Furthermore, the variables that influence the composite column behaviour and strength comprising different slenderness ratios, concrete strength and steel yield stress were investigated in a parametric study. It is shown that the increase in structural steel strength has a small effect on the composite column strength for the columns having higher relative slenderness ratios due to the flexural buckling failure mode. The composite column strengths obtained from the finite element analysis were compared with the design strengths calculated using the American Institute for Steel Construction AISC and Eurocode 4 for composite columns. Generally, it is shown that the EC 4 accurately predicted the design strength for the concrete encased steel composite columns having a concrete cylinder strength of 30 MPa and structural steel yield stresses of 275 and 460 MPa, which are in the limits of the code, which otherwise, was generally conservative. The AISC predictions were quite conservative for all the concrete encased steel composite columns. © 2010 Elsevier Ltd. All rights reserved.

La Grange A.,City University of Hong Kong | Pretorius F.,University of Hong Kong
Urban Studies | Year: 2016

The specificity of Hong Kong’s gentrification trajectory reflects its urban morphology, political institutions, and social and economic structure. While continuously renewing itself economically, much of the city’s inner urban area building stock is old and functionally obsolete, whilst nevertheless providing affordable, well-located housing for lower-income and disadvantaged groups and small-scale commercial clusters. Constrained redevelopment is not the result of economic decline but rather of formidable frictions that make land assembly and vacant possession of buildings difficult. Hong Kong’s executive-led, quasi democratic government articulates with the public ownership of land and its management through the leasehold system, and leads inner-city redevelopment through the Urban Renewal Authority (URA) supported by various institutional and statutory arrangements. (Re)development is favoured because it generates significant state revenue from physical and economic intensification of sites. Although gentrification is not an agenda of the URA, it is a significant outcome of its redevelopment activities. © 2014, © Urban Studies Journal Limited 2014.

Liang Z.,Chinese University of Hong Kong | Tang Q.,Chinese University of Hong Kong | Xu J.,Chinese University of Hong Kong | Miao Q.,Chinese University of Hong Kong | Miao Q.,University of Hong Kong
Advanced Materials | Year: 2011

An exploratory study on a group of silylethynylated N-heteropentacenes as soluble and stable organic semiconductors is presented. An interesting finding is that a silylethynylated N-heteropentacene can function as a p-type, n-type, or ambipolar organic semiconductor depending on the structure of its π-backbone. The tetraazapentacene derivative is one of the best performing n-type organic semiconductors with an electron mobility of up to 3.3 cm 2 V-1 s-1. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yu C.,Johnson Electric | Chau K.T.,University of Hong Kong
IEEE Transactions on Energy Conversion | Year: 2011

In this paper, a new type of memory motors, namely the dc-excited memory motor, is proposed and implemented. The concept of dc-excited memory is due to the nature that the magnetization level of permanent magnets (PMs) in the motor can be regulated by a temporary dc current pulse and be automatically memorized. Based on an outer-rotor doubly salient motor structure, the proposed dc-excited memory motor can offer effective and efficient online air-gap flux control. Hence, it possesses the advantages of mechanical robustness, high efficiency, and wide constant power operation region. Both simulation and experimentation are carried out to verify the validity of the proposed motor. © 2010 IEEE.

Leung S.S.K.,University of Hong Kong
International Journal of Women's Health | Year: 2010

Purpose: Cervical cancer screening has been consistently shown to be effective in reducing the incidence rate and mortality from cervical cancer. However, cervical screening attendance rates are still far from satisfactory in many countries. Strategies, health promotion and education programs need to be developed with clear evidence of the causes and factors relating to the low attendance rate. The study aims to assess the prediction of cervical screening attendance rate by Chinese women's knowledge about cervical cancer and cervical screening as well as their perception of health. Patients and methods: A survey with self-reported questionnaires was conducted on 385 Chinese women recruited from a community clinic in Hong Kong. Participants were Chinese women, Hong Kong residents, aged 18-65 years, able to read Chinese or English, and were not pregnant. Results: Women aged 37 years or less, with at least tertiary education, who perceived having control over their own health and had better knowledge on risk factors, were more likely to attend cervical cancer screening. Many participants had adequate general knowledge but were unable to identify correct answers on the risk factors. Conclusion: Health promotion efforts need to focus on increasing women's knowledge on risk factors and enhancing their perceived health control by providing more information on the link between screening and early detection with lower incidence rates and mortality from cervical cancer. © 2010 Leung and Leung.

Au W.Y.,University of Hong Kong
Hong Kong Medical Journal | Year: 2011

Arsenic trioxide has been used in traditional Chinese medicine for over 5000 years, but lost its appeal due to its toxicity. It was rediscovered in western medicine and enjoyed a renaissance from 1830 to 1930, as the first effective chemotherapy against syphilis, parasites and leukaemia. These years were also a time of political turmoil in China. The Nanking treaty (29 August 1842) turned Hong Kong into a colony, while the Xinhai Revolution (10 October 1911) gave birth to a republic of China. Arsenic returned to China and Hong Kong with the establishment of the first medical schools from 1887 to 1920. Until 1950, oral arsenic trioxide was the standard anti-leukaemic treatment in Queen Mary Hospital. The advent of alkylating chemotherapeutic agents replaced arsenic trioxide in Hong Kong and around the world. In the 1970s, however, the specific activity of arsenic trioxide against acute promyelocytic leukaemia was re-discovered during the Cultural Revolution in Harbin, China. In 1997, Hong Kong was returned to China. In the same year, arsenic trioxide returned to the world stage. Intravenous arsenic trioxide became the worldwide standard therapy for relapsed acute promyelocytic leukaemia. Oral administration of arsenic trioxide was revived in Hong Kong in 2000. This resulted in the first locally produced, registered, patented prescription drug in Hong Kong. Pending imminent manufacture, this product is poised to revolutionise acute promyelocytic leukaemia care and may hold the key to saving the lives of acute promyelocytic leukaemia patients worldwide. The remarkable journey of arsenic in the setting of medical history of China and Hong Kong is reviewed.

Cheung Y.-F.,University of Hong Kong
Korean Circulation Journal | Year: 2010

Arterial stiffness describes the rigidity of the arterial wall. Its significance owes to its relationship with the pulsatile afterload presented to the left ventricle and its implications on ventricular-arterial coupling. In adults, the contention that arterial stiffness as a marker and risk factor for cardiovascular morbidity and mortality is gaining support. Noninvasive methods have increasingly been adopted in both the research and clinical arena to determine local, segmental, and systemic arterial stiffness in the young. With adoption of these noninvasive techniques for use in children and adolescents, the phenomenon and significance of arterial stiffening in the young is beginning to be unveiled. The list of childhood factors and conditions found to be associated with arterial stiffening has expanded rapidly over the last decade; these include traditional cardiovascular risk factors, prenatal growth restriction, vasculitides, vasculopathies associated with various syndromes, congenital heart disease, and several systemic diseases. The findings of arterial stiffening have functional implications on energetic efficiency, structure, and function of the left ventricle. Early identification of arterial dysfunction in childhood may provide a window for early intervention, although longitudinal studies are required to determine whether improvement of arterial function in normal and at-risk paediatric populations will be translated into clinical benefits. Copyright ©2010 The Korean Society of Cardiology.

Wang K.,Nanjing University of Science and Technology | Chen M.Z.Q.,University of Hong Kong
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2012

This brief is concerned with the realization problem of biquadratic impedances, motivated by the recent development in passive mechanical control. This brief generalizes a realization procedure of a special class of biquadratic impedances to a more general form, and the resulting series-parallel RLC networks whose elements are no more than those in Bott-Duffin's networks are obtained without minimization. The realizability condition is proven by providing a constructive synthesis procedure. The series-parallel network obtained contains elements no more than those of Bott-Duffin's network when the impedance is nonregular. © 2004-2012 IEEE.

Guo Y.,CAS Institute of Chemistry | Xu L.,CAS Institute of Chemistry | Liu H.,CAS Institute of Chemistry | Li Y.,CAS Institute of Chemistry | Che C.-M.,University of Hong Kong
Advanced Materials | Year: 2015

Self-assembled functional nanoarchitectures are employed as important nanoscale building blocks for advanced materials and smart miniature devices to fulfi ll the increasing needs of high materials usage effi ciency, low energy consumption, and high-performance devices. One-dimensional (1D) crystalline nanostructures, especially molecule-composed crystalline nanostructures, attract signifi cant attention due to their fascinating infusion structure and functionality which enables the easy tailoring of organic molecules with excellent carrier mobility and crystal stability. In this review, we discuss the recent progress of 1D crystalline self-assembled nanostructures of functional molecules, which include both a small molecule-derived and a polymer-based crystalline nanostructure. The basic principles of the molecular structure design and the process engineering of 1D crystalline nanostructures are also discussed. The molecular building blocks, self-assembly structures, and their applications in optical, electrical, and photoelectrical devices are overviewed and we give a brief outlook on crucial issues that need to be addressed in future research endeavors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leung F.,University of Hong Kong
Journal of orthopaedic surgery (Hong Kong) | Year: 2012

To assess the one-year outcome of a dynamic hip screw (DHS) blade in the treatment of AO/OTA 31-A1 and 31-A2 intertrochanteric hip fractures. 35 men and 65 women aged 47 to 100 (mean, 83) years underwent fixation with a DHS blade for A1 (n=47) and A2 (n=53) intertrochanteric hip fractures after a low-energy injury. Patients were operated on within 48 hours of admission. Anteroposterior and lateral radiographs were examined for the tip-apex distance and femoral shortening. Potential complications were looked for, including implant migration, cut-out, loosening, or breakage. Functional outcome was based on the Parker mobility score. The 30-day and one-year mortality rates were 5% and 20%, respectively. At the one-year follow-up, 81 patients were available, and all fractures had healed without varus deformity. The mean tip-apex distance was 14.1 (range, 5.7-31.1; SD, 4.3) mm. The mean femoral shortening was 4.9 (range, 0-20.2; SD, 4.8) mm. The mean Parker score decreased to 3.8 at one-year follow-up from 5.9 before injury (p<0.001). There was one loss of fixation secondary to a non-traumatic subcapital fracture at 3 months, for which a bipolar hemiarthroplasty was performed. CONCLUSION; The DHS blade system is effective in treating AO/OTA 31-A1 and 31-A2 intertrochanteric hip fractures and results in a low complication rate.

Limited improvement in long term survival of lung cancer patients has been achieved by conventional chemotherapy or targeted therapy. To explore the potentials of tumor initiating cells (TIC)-directed therapy, it is essential to identify the cell targets and understand their maintenance mechanisms. We have analyzed the performance of ALDH/CD44 co-expression as TIC markers and treatment targets of lung cancer using well-validated in vitro and in vivo analyses in multiple established and patient-derived lung cancer cells. The ALDH(hi)CD44(hi) subset showed the highest enhancement of stem cell phenotypic properties compared to ALDH(hi)CD44(lo), ALDH(lo)CD44(hi), ALDH(lo)CD44(lo) cells and unsorted controls. They showed higher invasion capacities, pluripotency genes and epithelial-mesenchymal transition transcription factors expression, lower intercellular adhesion protein expression and higher G2/M phase cell cycle fraction. In immunosuppressed mice, the ALDH(hi)CD44(hi)xenografts showed the highest tumor induction frequency, serial transplantability, shortest latency, largest volume and highest growth rates. Inhibition of sonic Hedgehog and Notch developmental pathways reduced ALDH+CD44+ compartment. Chemotherapy and targeted therapy resulted in higher AALDH(hi)CD44(hi) subset viability and ALDH(lo)CD44(lo) subset apoptosis fraction. ALDH inhibition and CD44 knockdown led to reduced stemness gene expression and sensitization to drug treatment. In accordance, clinical lung cancers containing a higher abundance of ALDH and CD44-coexpressing cells was associated with lower recurrence-free survival. Together, results suggested theALDH(hi)CD44(hi)compartment was the cellular mediator of tumorigenicity and drug resistance. Further investigation of the regulatory mechanisms underlying ALDH(hi)CD44(hi)TIC maintenance would be beneficial for the development of long term lung cancer control.

Kuah-Pearce K.E.,University of Hong Kong
Anthropology and Medicine | Year: 2014

This paper will explore the social engagement of Buddhists through their active voluntary works - works that result in the development of a religious philanthropic culture. Through three case examples, this paper will examine how the sangha and individual Buddhists understand social suffering and compassion and attempt to integrate their understanding of Buddhist virtues and values in their daily life where the performance of voluntary works is seen as Buddhist spiritualism. In this process, the individuals seek to understand the key principles of Buddhism that are of direct relevance to their daily existence and their quest to be a compassionate self. Foremost are two notions of yebao (karma) and gan-en (gratitude) and how through compassionate practices and gratitude for those who accepted compassionate acts, they would be rewarded with good karma. Here, pursuing compassionate acts and the alleviation of social suffering is the pursuit of this-worldly spiritualism. © 2014 Taylor & Francis.

Ali J.R.,University of Hong Kong | Krause D.W.,State University of New York at Stony Brook
Journal of Biogeography | Year: 2011

Aim To evaluate the Gunnerus Ridge land-bridge hypothesis, which postulates a Late Cretaceous causeway between eastern Antarctica and southern Madagascar allowing the passage of terrestrial vertebrates. Location Eastern Antarctica, southern Indian Ocean, Madagascar. Methods The review involves palaeogeographical modelling, which draws upon geological and geophysical data, bathymetric charts, and plate tectonic reconstructions, and the evaluation of stratigraphically calibrated phylogenetic analyses to document ghost lineages of select taxa. Results The available geological and geophysical evidence indicates that eastern Antarctica's Gunnerus Ridge and southern Madagascar were separated for the entire Late Cretaceous by a vast marine expanse. In the mid-Late Cretaceous, the gap was probably punctuated by land on two intervening physiographical highs, the northern Madagascar Plateau and Conrad Rise, the latter of which, although probably large, was still separated from Antarctica's Riiser-Larsen Peninsula by c.1600km. Recent, stratigraphically calibrated phylogenies including large, terrestrial end-Cretaceous vertebrate taxa of Madagascar and the Indian subcontinent reveal long ghost lineages that extended into the Early Cretaceous. Main conclusions The view that Antarctica and Madagascar were connected by a long causeway between the Gunnerus Ridge and southern Madagascar in the Late Cretaceous, and that terrestrial vertebrates were able to colonize new frontiers using this physiographical feature, is almost certainly incorrect, as was previously demonstrated for the purported causeway between Antarctica and the Indian subcontinent across the Kerguelen Plateau. Connection across mainland Africa to account for the close relationships of several fossil and extant vertebrate taxa of Indo-Madagascar and South America is another option, although this too lacks credibility. We conclude that (1) throughout the Late Cretaceous there was no intervening, continuous causeway through Antarctica and associated land bridges between South America to the west and Indo-Madagascar to the east; and (2) mid- to large-sized, obligate terrestrial forms (e.g. abelisauroid theropod and titanosaurian sauropod dinosaurs and notosuchian crocodyliforms) gained broad distribution across Gondwanan land masses prior to fragmentation and were isolated on Indo-Madagascar before the end of the Early Cretaceous. © 2011 Blackwell Publishing Ltd.

Chan J.Y.W.,University of Hong Kong
Current Oncology Reports | Year: 2015

Nasopharyngeal carcinoma is a unique tumour which is endemic in southern China including Hong Kong. Whilst the treatment results for the primary cancer has been encouraging, management of recurrent tumours has been challenging. Compared to other surgical approaches, the maxillary swing operation provides wide access to the bilateral nasopharynx and the ipsilateral parapharyngeal space, allowing resection of tumours with adequate margins. Among the 312 patients who had received salvage nasopharyngectomy via the maxillary swing approach, the chance of achieving microscopically clear resection margins was 79.5 %. The overall local recurrence rate after surgery was 13.1 %. Multivariate analysis showed that resection margin status, synchronous nodal recurrence and cavernous sinus invasion were independent prognostic factors for overall survival. For small tumours located in the posterior wall, endoscopic resection, or more recently, the transoral robotic (TORS)-assisted approach, can be performed. Every effort should be made to ensure microscopic clearance of disease as well as to minimize the potential complications of surgery that may adversely affect the subsequent quality of life. © 2015, Springer Science+Business Media New York.

So S.,University of Hong Kong
Internet and Higher Education | Year: 2016

Smartphones could be the fastest spreading technology in human history. These mobile devices change the way we communicate and enable mobile and ubiquitous learning at a different level. This study evaluated the use of mobile instant messaging tools to support teaching and learning in higher education. A total of 61 undergraduate students enrolled at a teacher-training institute in Hong Kong who have smartphones with WhatsApp were assigned into experimental and control groups. Besides the traditional classroom learning for both groups, the experimental group was also supported with bite-sized multimedia materials and teacher-student interaction via WhatsApp outside school hours. The participants of the control group used WhatsApp only for academic communication. Pre-test scores were used as the covariate. The marginal means on the post-test scores showed that the participants in the experimental group performed better than those in the control group. The intervention of WhatsApp improved the learning achievement of the participants. The strength of the intervention between the two groups was medium to large. A questionnaire designed by the author was administered at the end of the study. The participants showed positive perception and acceptance of the use of WhatsApp for teaching and learning. The participants slightly rejected the view that receiving instructional materials and questions outside school hours could interfere with their private lives. The typical usability issues on mobile learning were found to be valid. The experience learnt in this research was discussed. © 2016 Elsevier Inc.

Jha V.,Jawaharlal Institute of Postgraduate Medical Education & Research | Jha V.,George Institute of Global Health | Garcia-Garcia G.,University of Guadalajara | Iseki K.,University of Ryukyus | And 7 more authors.
The Lancet | Year: 2013

Summary Chronic kidney disease is defined as a reduced glomerular filtration rate, increased urinary albumin excretion, or both, and is an increasing public health issue. Prevalence is estimated to be 8-16% worldwide. Complications include increased all-cause and cardiovascular mortality, kidney-disease progression, acute kidney injury, cognitive decline, anaemia, mineral and bone disorders, and fractures. Worldwide, diabetes mellitus is the most common cause of chronic kidney disease, but in some regions other causes, such as herbal and environmental toxins, are more common. The poorest populations are at the highest risk. Screening and intervention can prevent chronic kidney disease, and where management strategies have been implemented the incidence of end-stage kidney disease has been reduced. Awareness of the disorder, however, remains low in many communities and among many physicians. Strategies to reduce burden and costs related to chronic kidney disease need to be included in national programmes for non-communicable diseases. © 2013 Elsevier Ltd.

Chan T.M.,University of Hong Kong
Current Hepatitis Reports | Year: 2010

Glomerulonephritis is an important extrahepatic manifestation of chronic hepatitis B virus (HBV) infection. The uncommon occurrence, variability in renal histopathology, and heterogeneity in clinical course present challenges in clinical studies and have resulted in a relative paucity of data and uncertainty with regard to the optimal management of HBV-related glomerular diseases. The advent of nucleos(t)ide analogue medications that effectively suppress HBV replication has markedly altered the clinical outcomes of kidney transplant recipients with HBV infection, but the emergence of drug resistance is an escalating problem. This article reviews the recent knowledge of the pathogenesis and treatment of HBV-related membranous nephropathy, and discusses the management of hepatitis B in kidney transplant recipients, which is continuously evolving. © 2010 The Author(s).

Jim C.Y.,University of Hong Kong
Landscape and Urban Planning | Year: 2015

Many cities have inadequate green infrastructures and cannot benefit from ecosystem services brought by greenspaces. Global warming and urban heat island (UHI) effect impose a dual warming impact on cities, especially compact ones. Green roofs offer a plausible solution for climate adaptation. In compact humid-tropical Hong Kong, two green-roof and a control bare-roof plots were installed on a high-rise building. Precision sensors were installed along a holistic vertical temperature profile extending from outdoor air to roof surface, green-roof material layers, and indoor ceiling and air. Three apartments under the plots were kept vacant to monitor air-conditioning energy consumption. The comprehensive-systematic data allowed in-depth analysis of thermal performance of vegetation (Sedum and Perennial Peanut) and weather (sunny, cloudy and rainy) in summer. Intense solar radiation at Control plot triggered significant material heating, which in turn warmed near-ground air to intensify UHI effect and indoor space to lift energy consumption. Sedum plot with incomplete plant cover, sluggish transpiration and limited substrate moisture storage had feeble evapotranspiration cooling. The warmed roof passed heat to near-ground air and subsurface layers to impose a small indoor cooling load. Peanut plot with high transpiration rate can significantly cool foliage surface and near-ground air to ameliorate UHI. Its high moisture-holding capacity, however, can generate an appreciable heat-sink to push heat downwards and increase indoor cooling load. Practical hints on green roof design and management were distilled from the findings for application in Hong Kong and beyond and to contribute to climate-resilient cities. © 2015 Elsevier B.V.

Wang L.,Northeastern University China | Yung N.H.C.,University of Hong Kong
IEEE Transactions on Intelligent Transportation Systems | Year: 2012

In this paper, the problem of human detection in crowded scenes is formulated as a maximum a posteriori problem, in which, given a set of candidates, predefined 3-D human shape models are matched with image evidence, provided by foreground extraction and probability of boundary, to estimate the human configuration. The optimal solution is obtained by decomposing the mutually related candidates into unoccluded and occluded ones in each iteration according to a graph description of the candidate relations and then only matching models for the unoccluded candidates. A candidate validation and rejection process based on minimum description length and local occlusion reasoning is carried out after each iteration of model matching. The advantage of the proposed optimization procedure is that its computational cost is much smaller than that of global optimization methods, while its performance is comparable to them. The proposed method achieves a detection rate of about 2% higher on a subset of images of the Caviar data set than the best result reported by previous works. We also demonstrate the performance of the proposed method using another challenging data set. © 2011 IEEE.

Chui W.H.,University of Hong Kong | Chan H.C.,City University of Hong Kong
Child Abuse and Neglect | Year: 2013

Objective: Macau is a Special Administrative Region (SAR) of China with over 95% of the population is of Chinese descent. Research on school bullying using Macanese samples is virtually nonexistent. Thus, this study is among the first to sample this population by exploring the association between bullying perpetration and victimization, and the level of self-control among a group of school-aged Macanese adolescents. Methods: A total of 365 participants, aged between 10 and 17 years, from two male-only schools (a boarding and a non-boarding schools) in Macau are surveyed. The Illinois Bully Scale (Espelage & Holt, 2001) and Self-Control Scale (Grasmick, Tittle, Bursik, & Arneklev, 1993) are used to measure the participants bullying behaviors and self-control level, respectively. Results: Overall finding indicates that bullying perpetration is negatively associated with the participants' level of self-control. Conclusion: These findings provide further support for the importance of self-control in bullying perpetration. Implications of the findings are offered by way to increase the youngsters' level of self-control in order to reduce their propensity to engage in bullying perpetration at school. © 2012 Elsevier Ltd.

Lo S.H.,University of Hong Kong
Finite Elements in Analysis and Design | Year: 2012

A generic algorithm is proposed to merge structured and unstructured hexahedral meshes automatically into one single valid finite element mesh of hexahedral, tetrahedral and pyramid elements. In view of the success of merging arbitrary tetrahedral meshes in addressing the industrial need for rapid modification, update and manipulation of meshed objects, the merging algorithm is extended to hexahedral meshes by first dividing each hexahedral element into five or six tetrahedral elements. Non-intersected hexahedral elements can be easily recovered from the merged tetrahedral mesh as the constituent tetrahedra as a subdivision of the original hexahedral elements are intact and present in the mesh. Like the merging of tetrahedral meshes, the procedure is robust and efficient as all operations such as loops of intersection, incorporation of intersection segments, partition of boundary surfaces and identification of regions of intersection are deterministic and topological. The mesh merging algorithm provides a means to combine, modify and insert new features to existing hexahedral and tetrahedral meshes. It is also a powerful tool to create new meshes from existing hexahedral and tetrahedral meshes through the Boolean operations. High-quality regular hexahedral elements of the original mesh generated by mapping or extrusion will be preserved, which is important for finite element analysis as hexahedral elements are sensitive to shape distortions. Examples with details for each step of the mesh merging process are presented to elucidate the main ideas of the algorithm. © 2012 Elsevier B.V. All rights reserved.

Yip P.S.F.,University of Hong Kong | Caine E.D.,University of Rochester
Journal of Epidemiology and Community Health | Year: 2011

Background: Existing studies have described a strong correlation between unemployment rates and suicide rates, but the exact mechanisms through which they may interact with one another remain unknown. Method This study examined the complex relationships between suicide rates and both regional unemployment rates and individual employment status during times of economic recession (2000-3) and recovery (2003-6) in Hong Kong. Results: Despite the strong correlation (0.86) between the unemployment rates and suicide rates for 2000-6, the rates of suicides within the employed and unemployed groups moved in the opposite direction from the overall population trend. That is, the suicide rate among the unemployed decreased during economic recession and increased during recovery. Conclusion: It is important to be able to distinguish precisely between population-level concepts, such as rates, and individual-level characteristics, such as employment status, when considering the development of evidence-based suicide prevention strategies.

Kwan K.H.,Nanyang Technological University | So P.L.,Nanyang Technological University | Chu Y.C.,University of Hong Kong
IEEE Transactions on Industrial Electronics | Year: 2012

This paper proposes a novel control design for the unified power quality conditioner (UPQC). This design, enabled by a control framework that employs the output regulation (OR) theory, is also made up of an exogenous Kalman filter used to extract the state components of the distorted supply voltage and load current, and a plant Kalman filter as a state observer. In addition, the same framework integrates the major functions of the UPQC with ease to unify the treatments of several power quality problems including system harmonics in the supply voltage and load current, sags/swells in the supply voltage, variations in the load demands, and poor power factor at the supply side. A linear quadratic regulator-based self-charging circuit is also incorporated into the control design so that the UPQC operates without relying on an external dc source. Simulation and experimental studies on a single-phase power distribution system are used to verify the performance and real-time implementation of this control design with the UPQC. © 2012 IEEE.

Wang A.Y.M.,University of Hong Kong
Seminars in Nephrology | Year: 2011

The mortality of end-stage renal disease (ESRD) patients, including those receiving long-term peritoneal dialysis (PD), has remained unacceptably high owing to the prevalence of cardiovascular disease. It is well recognized that both traditional Framingham risk factors and kidney disease-related risk factors may contribute to the high prevalence of cardiovascular disease in these patients. Of the different risk factors, chronic inflammation frequently is observed in long-term PD patients. The causes of inflammation are usually complex and multifactorial, involving both dialysis-related and dialysis-unrelated factors. Inflammation is strongly associated with cardiovascular disease and malnutrition, and has been shown consistently to be a powerful predictor of mortality and adverse cardiovascular outcomes in PD patients. In this article we review the prevalence and potential causes of chronic inflammation in PD patients. More importantly, we provide emerging evidence that shows the serious consequences of chronic systemic inflammation in PD patients and the important contribution of inflammation to adverse clinical outcomes. © 2011 Elsevier Inc.

Wang Y.,University of Hong Kong
Diabetes and Metabolism Journal | Year: 2014

Ageing is the most significant risk factor for a range of prevalent diseases, including cancer, cardiovascular disease, and diabetes. Accordingly, interventions are needed for delaying or preventing disorders associated with the ageing process, i.e., promotion of healthy ageing. Calorie restriction is the only nongenetic and the most robust approach to slow the process of ageing in evolutionarily divergent species, ranging from yeasts, worms, and flies to mammals. Although it has been known for more than 80 years that calorie restriction increases lifespan, a mechanistic understanding of this phenomenon remains elusive. Yeast silent information regulator 2 (Sir2), the founding member of the sirtuin family of protein deacetylases, and its mammalian homologue Sir2-like protein 1 (SIRT1), have been suggested to promote survival and longevity of organisms. SIRT1 exerts protective effects against a number of age-associated disorders. Caloric restriction increases both Sir2 and SIRT1 activity. This review focuses on the mechanistic insights between caloric restriction and Sir2/SIRT1 activation. A number of molecular links, including nicotinamide adenine dinucleotide, nicotinamide, biotin, and related metabolites, are suggested to be the most important conduits mediating caloric restriction- induced Sir2/SIRT1 activation and lifespan extension. © 2014 Korean Diabetes Association.

Zhou F.,Tongji University | Young B.,University of Hong Kong
Engineering Structures | Year: 2013

This paper reports a numerical investigation of cold-formed high strength stainless steel square and rectangular hollow sections subjected to web crippling at elevated temperatures. Finite element analysis was conducted on cold-formed high strength austenitic and duplex stainless steel material. Four loading conditions specified in the American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures were investigated in the numerical study. A non-linear finite element model which includes geometric and material non-linearities was developed and verified against experimental results. It was shown that the finite element model closely predicted the web crippling strengths and failure modes of the tested specimens under the four loading conditions. Hence, parametric study was carried out to investigate the web crippling behaviour of cold-formed high strength stainless steel square and rectangular hollow sections at elevated temperatures. The web crippling strengths predicted from the finite element analysis were compared with the design strengths obtained using the American, Australian/New Zealand and European specifications for stainless steel structures by substituting the reduced material properties in the current web crippling design equations. A unified web crippling equation for cold-formed high strength stainless steel square and rectangular hollow sections at elevated temperatures is proposed. It is demonstrated that the web crippling strength obtained using the proposed equation is safe and reliable using reliability analysis. © 2013 Elsevier Ltd.

Chen J.-C.,CAS Institute of Physics | Wang J.,University of Hong Kong | Sun Q.-F.,CAS Institute of Physics
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The effect of magnetic field on electron transport in the inverted band structure of HgTe/CdTe quantum well is investigated. Although magnetic field breaks the time-reversal symmetry, the quantum spin Hall effect can still survive at large magnetic field up to 10 T. Moreover, two quantum anomalous Hall-like phases emerge, in which the system only has a spin-up or spin-down edge state at a given sample edge and the edge current is spin polarized. By tuning the Fermi energy, the system can transit between the quantum spin Hall phase and two quantum anomalous Hall-like phases, so the polarized direction of the edge current is well controllable. Thus the spin selectivity can be realized for potential applications of spintronics. Due to the quantum spin and anomalous Hall-like effects, the longitudinal and Hall resistances exhibit quantum plateaus. In addition, at certain magnetic field, some exotic plateaus like 23 fractional quantum Hall effect are also observed, where edge states with the same spin counterpropagate at the one edge. At last, these plateaus are hardly affected by Rashba spin-orbit interaction, Zeeman effect, and Anderson disorder. © 2012 American Physical Society.

Tao X.,City University of Hong Kong | Hui S.Y.R.,University of Hong Kong | Hui S.Y.R.,Imperial College London
IEEE Transactions on Industrial Electronics | Year: 2012

This paper presents a dynamic photoelectrothermal theory for light-emitting diode (LED) systems. In addition to photometric, electrical, and thermal aspects, this theory incorporates the time domain into the generalized equations. A dynamic model for a general LED system is developed for system analysis. This theory highlights the fact that the luminous output of an LED system will decrease with time from the initial operation to the steady state due to the rising temperature of the heat sink and the LED devices. The essential thermal time constants involved in the LED systems are explained. The time factor is critical in understanding how much the luminous output will decrease with time and is essential to the optimal designs of the LED systems that are operated continuously (e.g., general lighting) or momentarily (e.g., traffic lights). Experiments on several LED systems at different time frames have been conducted, and the practical measurements confirm the validity of this theory. © 2011 IEEE.

Jim C.Y.,University of Hong Kong
Landscape and Urban Planning | Year: 2015

Vertical greening can contribute to urban green infrastructure, urban heat-island amelioration and climate adaptation. Tropical greenwall practice, hindered by inadequate scientific knowledge and experience, can benefit from objective assessment of species performance and growth deficiency. Comprehensive survey of critical climber-plant traits shortlisted 20 potentially suitable species. A climber-selection matrix was established to facilitate species selection and greenwall design. Perennial woody climbers with ornamental flower or foliage and biological potential to reach 13-m height were preferred. They represented two attachment modes, namely mesh-climber and concrete-(bare-wall)climber groups. A field study was designed to monitor their growth from seedlings in experimental plots. Growth conditions were optimized by providing high-quality soil mix and irrigation. The 32-month study period included three active-growing seasons with two interspersed slow-growing seasons. Field assessment methods were developed to acquire systematic data on plant performance indicators and deficiency symptoms. Key attributes were selected to compute climber performance index (CPI) and climber deficiency index (CDI) as synoptic representation of greenwall-application suitability. Mesh-climbers performed much better than concrete-climbers across all key performance indicators, and with notably better CPI. They demonstrated faster establishment and growth rates and more ornamental flowers. The two groups had similar CDI mainly due to insufficient foliage density and foliage loss. For mesh-climbers, Quisqualis indica, Wisteria sinensis and Lonicera japonica had excellent performance, and the remaining species were good to fair. For concrete-climbers, only Parthenocissus dalzielii was rated good and Campsis grandiflora fair, with the rest poor to very poor. © 2015 Elsevier B.V..

Shiau W.-L.,Ming Chuan University | Chau P.Y.K.,University of Hong Kong
Industrial Management and Data Systems | Year: 2012

Purpose: The purpose of this paper is to understand blog continuance. Specifically, this paper aims to compare two theoretical models and an integrated model to identify which theoretical models best predicts blog continuance intention. Design/methodology/approach: An empirical study was conducted through an online survey. Data collected from six famous blogs in Taiwan (n = 361) were analyzed using structural equation modeling and pairwise nested F-tests. Findings: Results show that the ECT-IS model and the integrated model have greater explanatory power of blog continuance intention than the technology acceptance model (TAM). The results of pairwise nested F-tests show that the ECT-IS model exhibits statistically significant R 2 improvement compared to TAM. However, the R 2 improvement in the integrated model is not statistically different from that in the ECT-IS model. The ECT-IS model is also more parsimonious than the integrated model. Thus, the ECT-IS is a preferable model. Confirmation and satisfaction are salient factors influencing this intention. Practical implications - The results of this study provide useful information for blogging service providers (BSPs) to enhance and develop useful blog functions for user satisfaction. By revealing the differences and comparisons among these three models, this study can help BSPs promote the benefits of their blogs to strengthen the continuance intentions of their customers. Originality/value: This paper is one of the first studies to examine of influence change of variables and compare the relative ability of two competing theories, ECT-IS and TAM, and an integrated model in explaining blog continuance intention. The results confirm that the ECT-IS is a better model than the other two for explaining blog continuance intention. © Emerald Group Publishing Limited.

Lau R.Y.K.,University of Hong Kong | Xia Y.,Tsinghua University | Ye Y.,Harbin Institute of Technology
IEEE Computational Intelligence Magazine | Year: 2014

Abstract-There has been a rapid growth in the number of cybercr imes that cause tremendous financial loss to organizations. Recent studies reveal that cybercriminals tend to collaborate or even transact cyber-attack tools via the dark markets established in online social media. Accordingly, it presents unprecedented opportunities for researchers to tap into these underground cybercriminal communities to develop better insights about collaborative cybercrime activities so as to combat the ever increasing number of cybercrimes. The main contribution of this paper is the development of a novel weakly supervised cybercriminal network mining method to facilitate cybercrime forensics. In particular, the proposed method is underpinned by a probabilistic generative model enhanced by a novel context-sensitive Gibbs sampling algorithm. Evaluated based on two social media corpora, our experimental results reveal that the proposed method significantly outperforms the Latent Dirichlet Allocation (LDA) based method and the Support Vector Machine (SVM) based method by 5.23% and 16.62% in terms of Area Under the ROC Curve (AUC), respectively. It also achieves comparable performance as the state-of-the-art Partially Labeled Dirichlet Allocation (PLDA) method. To the best of our knowledge, this is the first successful research of applying a probabilistic generative model to mine cybercriminal networks from online social media. © 2014 IEEE.

Wang K.,Wuhan University | Choi S.H.,University of Hong Kong
Computers and Operations Research | Year: 2014

Flexible flow shop scheduling problems are NP-hard and tend to become more complex when stochastic uncertainties are taken into consideration. This paper presents a novel decomposition-based holonic approach (DBHA) for minimising the makespan of a flexible flow shop (FFS) with stochastic processing times. The proposed DBHA employs autonomous and cooperative holons to construct solutions. When jobs are released to an FFS, the machines of the FFS are firstly grouped by a neighbouring K-means clustering algorithm into an appropriate number of cluster holons, based on their stochastic nature. A scheduling policy, determined by the back propagation networks (BPNs), is then assigned to each cluster holon for schedule generation. For cluster holons of a low stochastic nature, the Genetic Algorithm Control (GAC) is adopted to generate local schedules in a centralised manner; on the other hand, for cluster holons of a high stochastic nature, the Shortest Processing Time Based Contract Net Protocol (SPT-CNP) is applied to conduct negotiations for scheduling in a decentralised manner. The combination of these two scheduling policies enables the DBHA to achieve globally good solutions, with considerable adaptability in dynamic environments. Computation results indicate that the DBHA outperforms either GAC or SPT-CNP alone for FFS scheduling with stochastic processing times. © 2013 Elsevier Ltd.

Gan R.-Y.,University of Hong Kong | Li H.-B.,Sun Yat Sen University
International Journal of Molecular Sciences | Year: 2014

Liver kinase B1 (LKB1), known as a serine/threonine kinase, has been identified as a critical cancer suppressor in many cancer cells. It is a master upstream kinase of 13 AMP-activated protein kinase (AMPK)-related protein kinases, and possesses versatile biological functions. LKB1 gene is mutated in many cancers, and its protein can form different protein complexes with different cellular localizations in various cell types. The expression of LKB1 can be regulated through epigenetic modification, transcriptional regulation and post-translational modification. LKB1 dowcnstream pathways mainly include AMPK, microtubule affinity regulating kinase (MARK), salt-inducible kinase (SIK), sucrose non-fermenting protein-related kinase (SNRK) and brain selective kinase (BRSK) signalings, etc. This review, therefore, mainly discusses recent studies about the expression, regulation, downstream signaling and cancer suppressive function of LKB1, which can be helpful for better understanding of this molecular and its significance in cancers. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Fox P.T.,Research Imaging Institute and | Fox P.T.,University of Texas Health Science Center at San Antonio | Fox P.T.,University of Hong Kong | Lancaster J.L.,Research Imaging Institute and | And 3 more authors.
Annual Review of Neuroscience | Year: 2014

Spatial normalization-applying standardized coordinates as anatomical addresses within a reference space-was introduced to human neuroimaging research nearly 30 years ago. Over these three decades, an impressive series of methodological advances have adopted, extended, and popularized this standard. Collectively, this work has generated a methodologically coherent literature of unprecedented rigor, size, and scope. Large-scale online databases have compiled these observations and their associated meta-data, stimulating the development of meta-analytic methods to exploit this expanding corpus. Coordinate-based meta-analytic methods have emerged and evolved in rigor and utility. Early methods computed cross-study consensus, in a manner roughly comparable to traditional (nonimaging) meta-analysis. Recent advances now compute coactivation-based connectivity, connectivity-based functional parcellation, and complex network models powered from data sets representing tens of thousands of subjects. Meta-analyses of human neuroimaging data in large-scale databases now stand at the forefront of computational neurobiology. © Copyright ©2014 by Annual Reviews. All rights reserved.

Fung M.L.,University of Hong Kong
Mediators of Inflammation | Year: 2015

Breathing difficulties in sleep are a hallmark of sleep-disordered breathing commonly observed in patients with sleep disorders. The pathophysiology of sleep apnea is in part due to an augmented activity of the carotid body chemoreflex. Arterial chemoreceptors in the carotid body are sensitive to inflammatory cytokines and immunogenic molecules in the circulation, because cytokine receptors are expressed in the carotid body in experimental animals and human. Intriguingly, proinflammatory cytokines are also locally produced and released in the carotid body. Also, there are significant increases in the expression of proinflammatory cytokines, cytokine receptors, and inflammatory mediators in the carotid body under hypoxic conditions, suggesting an inflammatory response of the carotid body. These upregulated cytokine signaling pathways could enhance the carotid chemoreceptor activity, leading to an overactivity of the chemoreflex adversely effecting breathing instability and autonomic imbalance. This review aims to summarize findings of the literature relevant to inflammation in the carotid body, with highlights on the pathophysiological impact in sleep apnea. It is concluded that local inflammation in the carotid body plays a pathogenic role in sleep apnea, which could potentially be a therapeutic target for the treatment of the pathophysiological consequence of sleep apnea. © 2014 Man Lung Fung.

Lo A.Y.,University of Hong Kong
Environmental Values | Year: 2015

China’s political environment offers limited space for critical debates on domestic politics. In such a constrained environment, people tend to represent and articulate climate change issues without explicitly addressing their political aspects. The aim of this paper is to examine this political ambiguity in climate change discourses. Q methodology was employed to elicit the subjective positions of forty-five young and educated Chinese individuals. Three discourses were extracted: namely, prosaic environmentalism, co-operative economic optimism and actor scepticism. These discourses do not indicate critical intent and deep engagement in the political arguments regarding climate change. This raises concern about the growth of climate citizenship within the country. © 2015 The White Horse Press.

Lai W.-F.,University of Hong Kong
Expert Review of Medical Devices | Year: 2011

Poly(ethylenimine) (PEI) has recently emerged as a favorable candidate for nucleic acid (NA) delivery because of its good effectivity at low cost. Despite copious derivatives and formulations being explored over the years, there is a scarcity of efforts to systematically review the current status and unmet needs of related research. The objective of this article is to fill this gap by revisiting the recent advances and challenges in in vivo NA delivery mediated by PEI. For this, related literature was retrieved from PubMed and Web of Science, and among the 530 articles yielded, 49 recent in vivo studies were selected for further analysis. Based on the distillation of literature, implications for research will be drawn and prospects of PEI-mediated NA delivery for stem cell- and RNA-based therapies will be explored. It is hoped that this article could add a new insight to the field and to clinical endeavors in the future. © 2011 Expert Reviews Ltd.

Gong T.,University of Hong Kong | Shuai L.,Johns Hopkins University
Proceedings of the Royal Society B: Biological Sciences | Year: 2012

Joint attention (JA) is important to many social, communicative activities, including language, and humans exhibit a considerably high level of JA compared with non-human primates. We propose a coevolutionary hypothesis to explain this degree-difference in JA: once JA started to aid linguistic comprehension, along with language evolution, communicative success (CS) during cultural transmission could enhance the levels of JA among language users. We illustrate this hypothesis via a multi-agent computational model, where JA boils down to a genetically transmitted ability to obtain non-linguistic cues aiding comprehension. The simulation results and statistical analysis show that: (i) the level of JA is correlated with the understandability of the emergent language; and (ii) CS can boost an initially low level of JA and 'ratchet' it up to a stable high level. This coevolutionary perspective helps explain the degree-difference in many language-related competences between humans and non-human primates, and reflects the importance of biological evolution, individual learning and cultural transmission to language evolution. © 2012 The Royal Society.

Yuan H.,Southwest Jiaotong University | Lu W.,University of Hong Kong | Jianli Hao J.,Ryerson University
Renewable and Sustainable Energy Reviews | Year: 2013

Construction waste comprises inert (e.g., sand, bricks, and concrete) and non-inert materials (e.g., bamboo, plastics, glass, wood, and paper). In Hong Kong, the inert portion can be deposited at public filling areas for land reclamation while the non-inert portion is disposed of at landfills. However, construction waste is usually a mixture of both inert and non-inert materials and thus a segregation of the two portions is of paramount importance for effective waste minimization. Previous studies have revealed that construction contractors in Hong Kong were unwilling to carry out on-site construction waste sorting (CWS) even though it has numerous advantages. After a decade, the situation should have changed, particularly given the promulgation of a waste charging scheme in 2006 imposing levies on different methods of construction waste disposal. This study thus aims at ascertaining the state-of-the-art on-site CWS practices in Hong Kong, with a particular interest in its evolution over the past ten years. Data was collected through case studies of six construction sites where a hybrid research method included a literature review, non-participant observations, and interviews. It was found that construction waste management (CWM) regulations have significantly enhanced on-site CWS in Hong Kong. Site space and project stakeholders' attitudes are still regarded as the most critical factors but labor and cost are no longer of major concerns in undertaking on-site CWS. Instead, a market for recyclables and an awareness of the profound environmental benefits are now perceived as being of major importance in these practices. Findings from the study can be used to review the effectiveness of current on-site CWS in Hong Kong, and through benchmarking they can also be used to develop good CWS practices in other economies. © 2012 Elsevier Ltd.

Ng C.-O.,University of Hong Kong | Wang C.Y.,Michigan State University
Microfluidics and Nanofluidics | Year: 2010

A mathematical model is presented for the problem of apparent slip arising from Stokes shear flow over a composite surface featuring mixed boundary conditions on the microscale. The surface can be composed of a bidimensional array of solid areas placed on an otherwise no-shear surface corresponding to an envelope over the tops of posts, or no-shear areas placed on an otherwise solid surface corresponding to an envelope over the tops of holes. Posts and holes of circular or square cross section, and solid areas of no-slip or partial-slip types are studied. Following some previously proposed scaling laws, the effective slip length is expressed as a certain function of the solid fraction for some specific cases. More refined equations based on linear regression of the computed results are obtained for these cases. Amounts of slippage arising from these bidimensional patterns are compared with those from the one-dimensional patterns of grooves/grates. It is also shown that a larger slip length can result from an arrangement where the pitch is larger in the spanwise direction than in the streamwise direction. © 2009 Springer-Verlag.

A strong dependence of thermal activation energy (TAE) on infrared (IR) stimulation time for the infrared stimulated luminescence (IRSL) signal was observed for K-feldspar grains extracted from several sediments and granites from China. A TAE value as low as ∼0.1 eV was observed at the beginning of IR stimulation and increased to ∼0.45 eV after 90 s. For a trap depth of ∼2 eV below the conduction band for the IRSL traps, the TAE value of ∼0.45 eV is consistent with the energy gap between the excited states (∼0.5 eV below the conduction band) and conduction band. This phenomenon is explained as the result of the coexistence of thermally assisted recombination via conduction band or band-tail states hopping and athermal tunnelling recombination of electrons from the excited states under IR stimulation, leading to the observation of a higher anomalous fading rate in the initial part of the IRSL decay curve. © 2010 Elsevier Ltd. All rights reserved.

Vanhoutte P.M.,University of Hong Kong
ACS Chemical Neuroscience | Year: 2013

The Serotonin Club has played a crucial role in disseminating information on the roles played by this monoamine neurotransmitter, as well as in the process of pharmacological classification of serotonin membrane receptors. The Club's future mission should be to emphasize that serotonin (5-hydroxytyptamine) contributes to physiology and pathology beyond its function in the central nervous system. © 2013 American Chemical Society.

We investigated if 18F-FDG PET/CT, DW-MRI, and DCE-MRI are able to predict preoperative chemoradiation therapy (CRT) response in patients with T3-4 rectal adenocarcinomas. MRI and PET/CT scans were performed within 1 week, at baseline, early midtreatment (2 weeks of CRT), and posttreatment (6 weeks after completing CRT). Responders (n = 4) and nonresponders (n = 4) were defined according to tumor regression grade by histology. Only SUVmax (P = 0.030) at early midtreatment could significantly differentiate between responders and nonresponders, suggesting that 18F-FDG PET/CT may be effective to predict early treatment response compared with DW-MRI and DCE-MRI in T3-4 rectal cancer.

Chesi G.,University of Hong Kong
IEEE Transactions on Robotics | Year: 2010

Image noise unavoidably affects the available image points that are used in visual-servoing schemes to steer a robot end-effector toward a desired location. As a consequence, letting the image points in the current view converge to those in the desired view does not ensure that the camera converges accurately to the desired location. This paper investigates the selection of object configurations to minimize the worst-case positioning error due to the presence of image noise. In particular, a strategy based on linear matrix inequalities (LMIs) and barrier functions is proposed to compute upper and lower bounds of this error for a given maximum error of the image points. This strategy can be applied to problems such as selecting an optimal subset of object points or determining an optimal position of an object in the scene. Some examples illustrate the use of the proposed strategy in such problems. © 2010 IEEE.

Cheung J.P.,University of Hong Kong
Journal of orthopaedic surgery (Hong Kong) | Year: 2010

Misdiagnosis and delayed treatment of Mycobacterium marinum infection is common because of its diverse manifestations. This leads to inappropriate use of antimicrobials, extension of the infection from the skin to the tenosynovium, and a poor prognosis (loss of tendons and prolonged immobilisation, secondary to multiple debridements and joint contractures). Clinicians should be aware of this type of infection, especially in subjects at risk (fishermen and aquarium enthusiasts), and those with a history of trauma coupled with exposure to water or marine life. A proactive approach to obtain a biopsy for histopathological and microbiological diagnosis is advised. Anti-mycobacterial treatment should be started promptly. The combined use of rifampicin, ethambutol, and clarithromycin appears to be effective, and debridement is indicated in patients with deep-seated infections.

Chan K.L.,University of Hong Kong
Child Abuse and Neglect | Year: 2014

Multiple forms of violence may co-occur on a child. These may include various forms of child victimization and different types of family violence. However, evidence that child victims are more likely to witness other types of family violence has been lacking in China. Using data of a large and diverse sample of children recruited from 6 regions in China during 2009 and 2010 (N= 18,341; 47% girls; mean age. = 15.9 years), the associations between child victimization and family violence witnessed were examined. Descriptive statistics and the associations between child victimization, demographic characteristics, and family violence witnessed were analyzed. Lifetime and preceding-year rates were 71.7% and 60.0% for any form of child victimization and 14.0% and 9.2% for poly-victimization (having four or more types of victimization), respectively. Family disadvantages (i.e., lower socio-economic status, single parents, and having more than one child in the family) were associated with child victimization and poly-victimization. Witnessing of parental intimate partner violence, elder abuse, and in-law conflict also increased the likelihood of child victimization and poly-victimization, even after the adjustment of demographic factors. Possible mechanisms for the links between family violence and child victimization are discussed. The current findings indicated the need for focusing on the whole family rather than the victim only. For example, screening for different types of family violence when child victims are identified may help early detection of other victims within the family. © 2014 Elsevier Ltd.

Lai W.-F.,University of Hong Kong
Journal of Biosciences | Year: 2011

Lifespan prolongation is a common desire of the human race. With advances in biotechnology, the mechanism of aging has been gradually unraveled, laying the theoretical basis of nucleic acid therapy for lifespan prolongation. Regretfully, clinically applicable interventions do not exist without the efforts of converting theory into action, and it is the latter that has been far from adequately addressed at the moment. This was demonstrated by a database search on PubMed and Web of Science, from which only seven studies published between 2000 and 2010 were found to directly touch on the development of nucleic acid therapy for anti-aging and/or longevity enhancing purposes. In light of this, the objective of this article is to overview the current understanding of the intimate association between genes and longevity, and to bring the prospect of nucleic acid therapy for lifespan prolongation to light. © 2011 Indian Academy of Sciences.

Lo A.Y.H.,Griffith University | Jim C.Y.,University of Hong Kong
Land Use Policy | Year: 2012

Residents' views are pertinent in urban-park design and management, yet they are often ignored. Social-empirical studies could enhance socially relevant park design. As a compact city, Hong Kong's limited greenspaces are often too small, surrounded by incompatible activities, and fail to meet user demands and expectations. This study explores the response of citizens living in the crowded urban milieu to inadequate greenspace provision. A questionnaire survey gleaned opinion from residents in representative residential neighbourhoods in old city and new towns. Green sites are appreciated more for pragmatic microclimatic and amenity benefits than social and high-order environmental functions. The principal limitations are deficiency in sports facilities and greenery. Respondents favour more trees, dispersed seating design and large parks. The preferences are mainly related to age, income, education and retirement status. The high-density living milieu may have weakened attitude and perception towards urban nature. The findings could inform public policies and programmes on urban parks. They call for an institutional restructuring to facilitate active public engagement in greenspace planning and management. © 2011 Elsevier Ltd.

Wong O.L.,University of Hong Kong
Social Work in Health Care | Year: 2010

This study aimed to examine the relational meaning of food, based on the results of a qualitative study of eight obese children (six male and two female) and their families in a Chinese society in Hong Kong. The children range in age from 7 to 13. Findings reveal the important bonding function of food in family relationships. Two clinical themes were identified from the data: (1) food bonding nurturer and obese child; (2) eating and the bonding relationship with extended family. Putting a child on a diet was found to disrupt the bonding between the nurturers and the obese child. Power struggles over the loyalty of the child in food provision were also observed. Implications for practice are discussed. © Taylor & Francis Group, LLC.

Wong V.,University of Hong Kong
The Cochrane database of systematic reviews | Year: 2013

Traumatic brain injury (TBI) can be life threatening depending on the severity of the insult to the brain. It can also cause a range of debilitating sequelae which require cognitive, motor, communication, emotional, or behavioral rehabilitation of varying intensity and duration. A number of studies conducted and published in China have suggested that acupuncture may be beneficial in the acute treatment and rehabilitation of TBI. To determine the efficacy and safety of acupuncture in the acute management or rehabilitation (or both) of patients with a TBI, including cognitive, neurological, motor, communication, emotional, or behavioral complications, or a combination of such complications. We searched the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE, EMBASE, CINAHL, AMED, PsycINFO and others. We also searched the Chinese Acupuncture Studies Register, the Studies Register of the Cochrane Complementary Medicine Field, NCCAM, and NIH Clinical Studies Database. Three major Mainland Chinese academic literature databases (CNKI, VIP and Wang Fang Data) were also searched using keywords in simplified Chinese. We searched all databases through December 2009, and some searches have been updated to October 2012. Randomized controlled studies evaluating different variants of acupuncture and involving participants of any age who had suffered a TBI. Included trials compared acupuncture with placebo or sham treatment, or acupuncture plus other treatments compared with the same other treatments. We excluded trials that only compared different variants of acupuncture or compared acupuncture alone against other treatments alone, as they did not yield the net effect of acupuncture. Two review authors identified potential articles from the literature search and extracted data independently using a data extraction form. We performed methodological assessment of included studies using the Cochrane Collaboration's tool for assessing risk of bias. We were unable to perform quantitative data analysis due to insufficient included studies and available data. Four RCTs, including 294 participants, reported outcomes specified by this review. Three investigated electro-acupuncture for TBI while one investigated acupuncture for acute TBI. The results seem to suggest that acupuncture is efficacious for these indications, however the low methodological quality of these studies renders the results questionable. No adverse effects of acupuncture were reported in any of the studies. The low methodological quality of the included studies does not allow us to make conclusive judgments on the efficacy and safety of acupuncture in either the acute treatment and/or rehabilitation of TBI. Its beneficial role for these indications remains uncertain. Further research with high quality trials is required.

Zhu J.-H.,Shenzhen University | Young B.,University of Hong Kong
Journal of Constructional Steel Research | Year: 2012

This paper presents the numerical simulation and design of cold-formed steel oval hollow section columns. An accurate finite element model was developed to simulate the fixed-ended column tests of oval hollow sections. The material non-linearities obtained from tensile coupon tests as well as the initial local and overall geometric imperfections were incorporated in the finite element model. Convergence study was performed to obtain the optimized mesh size. A parametric study consisted of 100 columns was conducted using the verified numerical model. The failure modes of material yielding, local buckling and flexural buckling as well as interaction of local and flexural buckling were found in this study. The experimental column strengths and numerical results predicted by the parametric study were compared with the design strengths calculated using the current North American, Australian/New Zealand and European specifications for cold-formed steel structures. In addition, the direct strength method, which was developed for cold-formed steel members for certain cross-sections but not cover oval hollow sections, was used in this study. The reliability of these design rules was evaluated using reliability analysis. © 2011 Elsevier Ltd. All rights reserved.

Shan Y.,University of Hong Kong
Sub-cellular biochemistry | Year: 2012

Oxygen has a great impact on the metabolism and physiology of microorganisms. It serves as the most efficient terminal electron acceptor to drive the energy conservation process of cellular respiration and is required in many biosynthetic reactions. Bacteria encounter oxygen fluctuation and limitation during their growth in both natural ecological niches and in laboratory vessels. In response to oxygen limitation, facultative bacteria undergo substantial metabolic reprogramming to switch from the aerobic respiration to either anaerobic respiration, fermentation, or photosynthesis. Two key factors determine the metabolic pathways bacteria adopt under oxygen deprived microaerobic and anaerobic conditions: maximal energy conservation and redox homeostasis. In this chapter, we first describe how the fulfillment of these two key factors governs the metabolic reprogramming of facultative bacteria and how the process is tightly controlled by several global regulatory factors: FNR, ArcBA, as well as NarL and NarP. We then utilizes fermentation of glycerol, a large surplus byproduct of biodiesel industry, as an example to illustrate how environment, process, and strain based approaches can be exploited to manipulate and engineer the anaerobic metabolic pathways so that desirable fermentation products can be achieved with optimal yield.

Yu F.,Zhejiang Sci-Tech University | Yang J.,University of Hong Kong
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012

This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter-a key factor reflecting the influence of pile embedment-whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option. ©2012 American Society of Civil Engineers.

Chow C.K.W.,University of Hong Kong
Journal of Air Transport Management | Year: 2014

This paper focuses on studying the relationship between customer satisfaction, measured by customer complaints, and the service quality of Chinese carriers. By using a quarterly unbalanced panel data set covering twelve large and small carriers, our fixed effect Tobit analysis shows that customer complaints rise with increases in the number of damaged bags, but at a declining rate. By contrast, the on-time performance of scheduled flights has no significant effect on customer complaints. Furthermore, non-state or privately owned carriers receive significantly more customer complaints compared with state-owned carriers, and the largest number of complaints are made in the third quarter, which covers the high season of the summer holidays. © 2013 Elsevier Ltd.

Chan J.Y.W.,University of Hong Kong
Oral Oncology | Year: 2014

Objectives: Nasopharyngeal carcinoma is a unique tumour which is endemic in Southern China including Hong Kong. While the treatment results for primary cancer has been encouraging, management of persistent or recurrent tumours has been challenging. Compared to other surgical approaches, the maxillary swing operation provides spacious access to the bilateral nasopharynx and the ipsilateral parapharyngeal space, allowing resection of tumours with wide margins. In this article, we will present our results in the surgical management of recurrent nasopharyngeal carcinoma.Materials and Methods: Retrospective review.Results: Over the years, we have performed salvage maxillary swing nasopharyngectomy for 312 patients. Microscopic negative resection margins were achieved in the majority (79.5%) of the patients. The overall local recurrence rate after surgery was 13.1%, the risk of which was significantly higher in patients with previous positive resection margins. The overall 5-year actuarial local tumour control and overall survival was 74% and 62%, respectively, which was significantly higher in patients with clear resection. For small tumours located in the posterior wall, minimally invasive approach can be used, which included the endoscopic resection, or more recently, the transoral robotic (TORS) assisted approach.Conclusion: The result of surgical salvage of recurrent nasopharyngeal carcinoma is promising. Every effort should be made to ensure microscopic clearance of disease as well as to minimize the potential complications of surgery that may adversely affect the subsequent quality of life. © 2013 Elsevier Ltd. All rights reserved.

Lui W.Y.,University of Hong Kong
Advances in experimental medicine and biology | Year: 2012

Spermatogenesis involves precise co-ordination of multiple cellular events that take place in the seminiferous epithelium composed of Sertoli cells and developing germ cells during the seminiferous epithelial cycle. Given the cyclic and co-ordinated nature of spermatogenesis, temporal and spatial expression of certain genes pertinent to a specific cellular event are essential. As such, transcriptional regulation is one of the major regulatory machineries in controlling the cell type- and stage-specific gene expression, some of which are under the influence of gonadotropins (e.g., FSH and LH) and sex steroids (e.g., testosterone and estradiol-17beta). Recent findings regarding transcriptional control of spermatogenesis, most notably target genes at the Sertoli-Sertoli and Sertoli-spermatid interface at the site of the blood-testis barrier (BTB) and apical ectoplasmic specialization (apical ES), respectively, involving in cell adhesion are reviewed and discussed herein. This is a much neglected area of research and a concerted effort by investigators is needed to understand transcriptional regulation of cell adhesion function in the testis particularly at the BTB during spermatogenesis.

Huang K.,University of Hong Kong | Lau V.K.N.,Hong Kong University of Science and Technology
IEEE Transactions on Wireless Communications | Year: 2014

Microwave power transfer (MPT) delivers energy wirelessly from stations called power beacons (PBs) to mobile devices by microwave radiation. This provides mobiles practically infinite battery lives and eliminates the need of power cords and chargers. To enable MPT for mobile recharging, this paper proposes a new network architecture that overlays an uplink cellular network with randomly deployed PBs for powering mobiles, called a hybrid network. The deployment of the hybrid network under an outage constraint on data links is investigated based on a stochastic-geometry model where single-antenna base stations (BSs) and PBs form independent homogeneous Poisson point processes (PPPs) with densities λ-b and λ-p, respectively, and single-antenna mobiles are uniformly distributed in Voronoi cells generated by BSs. In this model, mobiles and PBs fix their transmission power at p and q, respectively; a PB either radiates isotropically, called isotropic MPT, or directs energy towards target mobiles by beamforming, called directed MPT. The model is used to derive the tradeoffs between the network parameters (p, λ-b, q, λ-p) under the outage constraint. First, consider the deployment of the cellular network. It is proved that the outage constraint is satisfied so long as the product pλ-b^\frac{alpha}{2} is above a given threshold where α is the path-loss exponent. Next, consider the deployment of the hybrid network assuming infinite energy storage at mobiles. It is shown that for isotropic MPT, the product qλ-p λ-b^\frac{alpha}{2} has to be above a given threshold so that PBs are sufficiently dense; for directed MPT, z-mqλ-p λ-b^\frac{alpha}{2} with z-m denoting the array gain should exceed a different threshold to ensure short distances between PBs and their target mobiles. Furthermore, similar results are derived for the case of mobiles having small energy storage. © 2002-2012 IEEE.

Chung K.K.H.,The Hong Kong Institute of Education | Ho C.S.-H.,University of Hong Kong
Journal of Learning Disabilities | Year: 2010

This study examined the relations between reading-related cognitive skills and word reading development of Chinese children with dyslexia in their Chinese language (L1) and in English (L2). A total of 84 bilingual children-28 with dyslexia, 28 chronological age (CA) controls, and 28 reading-level (RL) controls-participated and were administered measures of word reading, rapid naming, visual-orthographic skills, and phonological and morphological awareness in both L1 and L2. Children with dyslexia showed weaker performance than CA controls in both languages and had more difficulties in phonological awareness in English but not in Chinese. In addition, reading-related cognitive skills in Chinese contributed significantly to the ability to read English words, suggesting cross-linguistic transfer from L1 to L2. Results found evidence for different phonological units of awareness related to the characteristics of the different languages being learned, supporting the psycholinguistic grain size and linguistic coding differences hypotheses. © Hammill Institute on Disabilities 2010.

Chesi G.,University of Hong Kong
IEEE Transactions on Automatic Control | Year: 2014

This technical note addresses the design of robust static output feedback controllers that minimize a polynomial cost and robustly stabilize a system with polynomial dependence on an uncertain vector constrained in a semialgebraic set. The admissible controllers are those in a given hyper-rectangle for which the system is well-posed. First, the class of robust stabilizability functions is introduced, i.e., the functions of the controller that are positive whenever the controller robustly stabilizes the system. Second, the approximation of a robust stabilizability function with a controller-dependent lower bound is proposed through a sums-of-squares (SOS) program exploiting a technique developed in the estimation of the domain of attraction. Third, the derivation of a robust stabilizing controller from the found controller-dependent lower bound is addressed through a second SOS program that provides an upper bound of the optimal cost. The proposed method is asymptotically non-conservative under mild assumptions. © 1963-2012 IEEE.

Duan B.,Cornell University | Wang M.,University of Hong Kong
MRS Bulletin | Year: 2011

Rapid prototyping (RP) technologies, which are based on computer-aided design and computer-aided manufacturing, are widely employed in traditional industries. They are capable of achieving extensive and detailed control over the architecture of objects to be formed and therefore are increasingly used in the biomedical engineering field. Selective laser sintering (SLS), a versatile RP technique, uses a laser beam to selectively sinter powdered materials to form three-dimensional objects according to designs that can be based on data obtained from computer-based medical imaging technologies. In this article relating to biomedical applications, the principle, materials, machine modification, and parameter optimization for SLS are reviewed. Biomedical applications of SLS, especially in the fabrication of tissue engineering scaffolds and drug/biomolecule delivery vehicles, are presented and discussed. SLS exhibits great potential for many applications in biomedical engineering. Copyright © Materials Research Society 2011.

Lemke K.H.,University of Hong Kong | Seward T.M.,Victoria University of Wellington
Chemical Physics Letters | Year: 2013

The M06-2X and B2PLYP-D functionals have been applied to predict structures and energies for (CO2)n clusters up to n = 16. A comparison between M06-2X, B2PLYP-D and benchmark CCSD(T) results indicates that M06-2X is capable of providing accurate binding energies. Stepwise M06-2X (CO2)n clustering free energies exhibit a sharp discontinuity at the magic cluster size n = 13 and systematically shift to more exergonic values with decreasing temperature, in particular for larger clusters. These results indicate that the M06-2X method provides an accurate and cost effective description of non-covalent interactions in (CO2) n clusters and therefore may provide important information on CO 2 nucleation phenomena. © 2013 Elsevier B.V. All rights reserved.

Yeung M.L.,University of Hong Kong | Jeang K.-T.,National Institute of Allergy and Infectious Diseases
Pharmaceutical Research | Year: 2011

MicroRNAs (miRNAs) are small physiological non-coding RNAs that regulate gene expression through an RNA interference (RNAi) mechanism. The expression of miRNAs is tightly controlled both spatially and temporally. Aberrant miRNA expression has been correlated with various cancers. Recent findings suggest that some miRNAs can function as tumor suppressors or oncogenes. In model experiments, the cancer phenotype of some cells can be reverted to normal when the cells are treated with miRNA mimics or inhibitors. Here, we discuss in brief the potential utility of miRNA-based cancer therapy as well as the current limitations thwarting their useful clinical application. © 2011 Springer Science + Business Media, LLC (outside the USA).

Cowling B.J.,University of Hong Kong
Pediatric Infectious Disease Journal | Year: 2012

Background: Annual vaccination against seasonal influenza viruses is recommended for school-age children in some countries. There are limited data on the immunogenicity and efficacy of repeated influenza vaccinations. Methods: In a randomized controlled trial, we administered seasonal trivalent inactivated influenza vaccine (TIV) or placebo to 64 children 6-15 years of age in two consecutive years and explored their humoral antibody responses. Results: Receipt of TIV in the first year was associated with lower antibody titer rises in the second year to seasonal influenza A(H1N1) and A(H3N2) strains for which the vaccine strains remained unchanged. Antibody response to a different influenza B strain in the second year was unaffected by receipt of TIV in the first year. Children who received TIV in both years showed higher antibody titers against pandemic A(H1N1) which was not included in either TIV. Conclusions: Results from our study suggest that humoral antibody response to TIV may be lower in children receiving repeated vaccination, but receipt of TIV induced seroprotection in most subjects. Our study was underpowered to explore whether differences in immunogenicity translated to differences in vaccine efficacy. © 2012 by Lippincott Williams and Wilkins.

Sun S.,University of Hong Kong
IEEE Microwave and Wireless Components Letters | Year: 2011

A simple microstrip ring-resonator is presented for novel design of dual-band dual-mode bandpass filters with good isolation and upper-stopband performance. By increasing the length of the loaded open-circuited stub, the two first-order degenerate modes are excited and slit for the use of the first passband, while one of the third-order degenerate modes moves downward and forms the second passband together with a second-order degenerate mode. Meanwhile, three transmission zeros are properly tuned for the rejections between the two passbands and in the upper stopband. After installing two coupled-line sections on a square ring at the two ports with 90°-separation, a dual-band filter with the two transmission poles in each passband is designed and measured. Without adding any additional perturbation element inside the ring, the measured filter shows good performance for both in-band matching and outside rejections of the desired dual passbands. © 2011 IEEE.

Zhang X.,University of Hong Kong
Renewable and Sustainable Energy Reviews | Year: 2015

Green real estate development is one of measures being implemented to reduce negative impacts of the building industry on the environment, society, and economy. However, there is lack of a systematic review of this large number of studies that is critical for the future endeavor. This paper reviews the existing body of knowledge related to green development. At first, the common research themes on green real estate development were identified, including concept, measure, business, and result. Then, the connotation and denotation of green real estate development was introduced in four dimensions. Third, the stakeholders of green real estate development and its benefits and costs were expatiated. Then, how to realize the green real estate development and its current weakness were analyzed in various aspects. It is found that the existing studies mainly focus on the environmental aspect of green building, other dimensions of sustainability of green building, especially the social sustainability is largely overlooked. Future research opportunities were identified such as the innovation of evaluation systems, integration of planning and design frameworks, management mechanisms and financing modes, and future proofing. © 2015 Elsevier Ltd All rights reserved.

Biped humanoid robots have gained much popularity in recent years. These robots are mainly controlled by two major control methods, the biologically-inspired approach based on Central Pattern Generator (CPG) and the engineering-oriented approach based on Zero Moment Point (ZMP). Given that flexibility in the body torso is required in some human activities, we believe that it is beneficial for the next generation of humanoid robots to have a flexible spine as humans do. In order to cope with the increased complexity in controlling this type of robot, a new kind of control system is necessary. Currently, there is no controller that allows a flexible spine humanoid robot to maintain stability in real-time while walking with dynamic spine motions. This paper presents a new hybrid CPG-ZMP control system for the walking of a realistically simulated flexible spine humanoid robot. Experimental results showed that using our control method, the robot is able to adapt its spine motions in real-time to allow stable walking. Our control system could be used for the control of the next generation humanoid robots. © 2009 Elsevier Ltd. All rights reserved.

Cheung V.Y.T.,University of Hong Kong
Journal of Ultrasound in Medicine | Year: 2013

High-intensity focused ultrasound therapy has received increasing interest in the management of solid malignancies and benign tumors. Magnetic resonance imaging has always been used to define the target for controlling and monitoring the ablation. Recently, sonographically guided high-intensity focused ultrasound has been introduced to monitor the ablation process. This article provides an overview of the background, clinical use, and treatment outcomes of sonographically guided high-intensity focused ultrasound in the treatment of uterine fibroids. © 2013 by the American Institute of Ultrasound in Medicine.

Expressions of gratitude often occur as functional lexical chunks such as thanks and thank you (Coulmas, 1981). In this paper, I will focus on the use of such units and longer formulaic sequences of gratitude such as thanks a lot and thank you very much, relying on data from the Hong Kong component of the International Corpus of English (ICE-HK). The results show that Hong Kong speakers of English do not employ the wide variety of thanking strategies that has been investigated in previous literature. Their expressions of gratitude are usually brief, with thanks and thank you being the commonest forms of gratitude expression. These forms are frequently used as closing signals; they often constitute a complete turn. Repetitive gratitude formulae and expressions of appreciation of the interlocutors (both in a single turn and across turns) are exceedingly rare, which suggests that the Chinese may be too reserved to express their gratitude openly and explicitly. Responses to an act of thanking seem to be infrequent in ICE-HK and only a few strategies are represented. The paper also considers the pedagogical implications of the way this function can be acquired in a second/foreign language with the help of the corpus findings. © 2009 Elsevier B.V. All rights reserved.

Zhang X.,Huazhong University of Science and Technology | Huang G.Q.,University of Hong Kong
International Journal of Production Economics | Year: 2010

This paper deals with simultaneous configuration of platform products and supply chains. The supply chain consists of one manufacturer and multiple cooperative suppliers. A common platform is shared for developing/configuring the product family with variant modules which are substitutable in the sense that high-performance module options can replace low-performance ones. As the customer in the supply chain, the manufacturer takes its leading role by making the first move to produce decisions on platform products configuration (PPC) and supplier selection. The manufacturer and concerned suppliers then move cooperatively to make their ordering and pricing decisions with a common objective to maximize their joint payoffs. We derive the optimal solution ranges for this two-moves dynamic game according to Nash's bargaining model. An iterative algorithm is developed to find the subgame perfect equilibrium. A numerical study is conducted through a series of simulation experiments to illustrate how useful insights about the mutual impacts between the PPC and SCC (supply chain configuration) decisions can be obtained from the proposed game models and solution procedure. The results are further compared with those obtained in a previous study with non-cooperative suppliers. The comparative study allows us to appreciate managerial measures under different supply chain coordination schemes. It is found that a supply chain with cooperative suppliers is more effective by using the lot-for-lot policy and more competitive by accommodating higher product variety. © 2009 Elsevier B.V. All rights reserved.

Yuan Y.,University of Houston | Yin G.,University of Hong Kong
Statistics in Medicine | Year: 2011

In oncology, dose escalation is often carried out to search for the maximum tolerated dose (MTD) in phase I clinical trials. We propose a Bayesian hybrid dose-finding method that inherits the robustness of model-free methods and the efficiency of model-based methods. In the Bayesian hypothesis testing framework, we compute the Bayes factor and adaptively assign a dose to each cohort of patients based on the adequacy of the dose-toxicity information that has been collected thus far. If the data observed at the current treatment dose are adequately informative about the toxicity probability of this dose (e.g. whether this dose is below or above the MTD), we make the decision of dose assignment (e.g. either to escalate or to de-escalate the dose) directly without assuming a parametric dose-toxicity curve. If the observed data at the current dose are not sufficient to deliver such a definitive decision, we resort to a parametric dose-toxicity curve, such as that of the continual reassessment method (CRM), in order to borrow strength across all the doses under study to guide dose assignment. We examine the properties of the hybrid design through extensive simulation studies, and also compare the new method with the CRM and the '3 + 3' design. The simulation results show that our design is more robust than parametric model-based methods and more efficient than nonparametric model-free methods. © 2011 John Wiley & Sons, Ltd.

Zhou B.,Harbin Institute of Technology | Duan G.-R.,Harbin Institute of Technology | Lam J.,University of Hong Kong
Automatica | Year: 2010

By exploring some geometric properties of the logarithmic quantizer and using the fact that the logarithmic quantizer is sector bounded and nondecreasing, this paper presents a new approach to the stability analysis of quantized feedback control systems. Our method is based on Tsypkin-type Lyapunov functions that have been widely used in absolute stability analysis problems. The results are expressed in linear matrix inequalities (LMIs) and are valid for both single-input and multiple-input discrete-time linear systems with a logarithmic quantizer. Both theoretical analysis and numerical examples show that the results in this paper are generally less conservative than those in the quadratic framework. © 2009 Elsevier Ltd. All rights reserved.

Chan T.M.,University of Hong Kong
Nature Reviews Nephrology | Year: 2015

Lupus nephritis is a common and severe manifestation of systemic lupus erythematosus, and an important cause of both acute kidney injury and end-stage renal disease. Despite its aggressive course, lupus nephritis is amenable to treatment in the majority of patients. The paradigm of immunosuppressive treatment for lupus nephritis has evolved over the past few decades from corticosteroids alone to corticosteroids combined with cyclophosphamide. Sequential treatment regimens using various agents have been formulated for induction and long-term maintenance therapy, and mycophenolate mofetil has emerged as a standard of care option for both induction and maintenance immunosuppressive treatment. The current era has witnessed the emergence of multiple novel therapeutic options, such as calcineurin inhibitors and biologic agents that target key pathogenetic mechanisms of lupus nephritis. Clinical outcomes have improved in parallel with these therapeutic advances. This Review discusses the evidence in support of current standard of care immunosuppressive treatments and emerging therapies, and describes their roles and relative merits in the management of patients with lupus nephritis. © 2015 Macmillan Publishers Limited. All rights reserved.

Lo S.H.,University of Hong Kong
Finite Elements in Analysis and Design | Year: 2014

In view of the simplicity and the linearity of regular grid insertion, a multi-grid insertion scheme is proposed for the three-dimensional Delaunay triangulation of non-uniform point distributions by recursive application of the regular grid insertion to an arbitrary subset of the original point set. The fundamentals and difficulties of three-dimensional Delaunay triangulation of highly non-uniformly distributed points by the insertion method are reviewed. Current strategies and methods of point insertions for non-uniformly distributed spatial points are discussed. An enhanced kd-tree insertion algorithm with a specified number of points in a cell and its natural sequence derived from a sandwich insertion scheme is also presented. The regular grid insertion, the enhanced kd-tree insertion and the multi-grid insertion have been rigorously studied with benchmark non-uniform distributions of 0.4-20 million points. It is found that the kd-tree insertion is more efficient in locating the base tetrahedron, but it is also more sensitive to the triangulation of non-uniform point distributions with a large amount of conflicting elongated tetrahedra. Including the grid construction time, multi-grid insertion is the most stable and efficient for all the uniform and non-uniform point distributions tested. © 2014 Elsevier B.V.

Cheung Y.-F.,University of Hong Kong
Nature Reviews Cardiology | Year: 2012

Heart failure is a major health problem in developed countries and a growing one in developing countries. Cardiac remodeling in heart failure affects myocardial mechanics, which requires comprehensive evaluation in three dimensions. The novel technique of 3D wall motion tracking applies speckle tracking technology to full volume, 3D echocardiographic datasets. Quantification of conventional and novel left ventricular (LV) parameters including volumes, ejection fraction, global and regional 3D strain, endocardial area strain, twist, and dyssynchrony, and identification of the site of latest mechanical activation are feasible on the basis of a single acquisition of a full-volume dataset. Clinical applications of 3D wall motion tracking include the assessment of global and regional LV performance in ischemic and nonischemic heart diseases, evaluation of mechanics in cardiomyopathies and congenital heart disease, potential selection of patients for cardiac resynchronization therapy and prediction of their response, and detection of subclinical cardiac dysfunction in diseases with likelihood of progression to heart failure. Technological advances with improvement in spatial and temporal resolution of this novel imaging modality are expected. Although 3D wall motion tracking is still in its infancy, this method has begun to provide new insights into LV mechanics and has already found clinical applications. Future developments in 3D assessment of right ventricular and myocardial layer-specific mechanics are awaited. © 2012 Macmillan Publishers Limited. All rights reserved.

Danchin A.,AMAbiotics SAS | Danchin A.,University of Hong Kong
FEBS Letters | Year: 2012

Using comparative genomics and functional analysis, this work summarises how the cell's genome is organised, with emphasis on the importance of the cell's chassis. Some discrete but important engineering constraints are reviewed, beginning with the need for scaffolds, as well as the question posed by the difficult task of putting a very long random thread (DNA) into a limited volume. Subsequently, to illustrate overlooked essential functions, we show the importance of safety valves, as well as the need to cope with leftovers. The third section discusses how transplantation experiments point out a remarkable feature of the cell factory: the program replicates (makes identical copies of itself), whereas the cell reproduces (makes similar copies of itself), placing in the limelight the role of informational maintenance. A final section identifies the need to put together a globally linear behaviour of the cell with intrisically non-linear genetic constructs. The discussion ends with the central question of evolvability of artificial constructs and to suggest that combining in vivo Synthetic Biology with biochemical reactors might be an efficient way forward. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Poon R.T.P.,University of Hong Kong | Borys N.,Celsion Corporation
Future Oncology | Year: 2011

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer death worldwide. No more than 30% of HCC patients are considered suitable for curative treatment because of tumor size and severity of liver impairment, among other factors. Radiofrequency ablation (RFA) monotherapy can cure small (<3 cm) HCC tumors. An adjuvant that interacts synergistically with RFA might enable curative therapy for many HCC patients with lesions >3 cm. Lyso-thermosensitive liposomal doxorubicin (LTLD) consists of the heat-enhanced cytotoxic doxorubicin within a heat-activated liposome. LTLD is infused intravenously prior to RFA. When heated to >39.5° ,°C, LTLD releases doxorubicin in high concentrations into the tumor and the tumor margins. The RFA plus LTLD combination has shown a statistically significant dose-response effect for time to treatment failure in a Phase I trial in which most subjects (62.5%) had tumors >3 cm. RFA plus LTLD is currently being evaluated in a 600-patient randomized, double-blind, dummy-controlled trial. © 2011 Future Medicine Ltd.

Ngan A.H.W.,University of Hong Kong
Scripta Materialia | Year: 2011

The power-law scaling of size effect of strength in micro-crystals is explained in terms of an assumed fractal geometry of the initial dislocation network. The size effect arises from the Taylor-type resistance in such a network. The power exponent of the size effect is predicted to be 3/(q + n), where q is the fractal dimension of the dislocation network, and n is the stress exponent of dislocation velocity. The theory is verified by a set of experimental strength data of Al micro-pillars. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Greenland K.B.,University of Hong Kong
Current Opinion in Anaesthesiology | Year: 2012

Purpose of review: This review will focus on two key aspects of difficult airway management in an ambulatory surgical center (ASC). First, the selection process of patients with known difficult airways suitable for this environment, and second, the requirements of a difficult airway cart to manage unexpected airway problems. Recent findings: The decision whether to manage a patient with a previously documented difficult airways in an ASC requires a multidisciplinary approach. Many factors will influence this decision including the cause and severity of the airway problem, the type of procedure, the experience of the perioperative staff, and the availability of difficult airway management devices.Unexpected difficult airways will always occur in anesthesia. Difficult airway carts are, therefore, a requirement for any area in which anesthesia is to be conducted. The contents of these carts should reflect the need to maintain patient oxygenation to avoid morbidity and mortality. Regular training sessions should include both technical training in the use of equipment and nontechnical training to improve interpersonal communication during crises. Summary: The management of ambulatory surgical practices must provide suitable difficult airway management equipment as well as technical and nontechnical training. Patients may present to an ASC with expected and unexpected difficult airways. Appropriate management of these patients requires advance planning to avoid poor outcomes. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Lee P.H.,University of Hong Kong
American Journal of Clinical Nutrition | Year: 2013

Background: Accelerometers are gaining popularity for the assessment of the physical activity level; however, compliance is a problem that results in missing data. Data from study days in which the accelerometer is not worn for a number of hours that are sufficient to reach a predetermined cutoff value are considered invalid and discarded. The problem of missing data is commonly handled by imputation; however, all traditional imputation methods ignore the available information from invalid days. Objective: In this study, I propose a new approach to the imputation of missing accelerometer data that takes into account the data available from invalid days. Design: A total of 4069 participants in NHANES waves 2003-2004 and 2005-2006 who provided 7 d of valid accelerometer data were used to illustrate this new approach. The method of imputation was a combined approach that combined the available data from valid days and invalid days to impute missing values. Simulation studies were carried out to compare this new combined approach with the traditional imputation method for 1) accuracy and 2) effect-size estimation of the sexphysical activity relation by using the root mean squared error (RMSE). Results: The combined approach performed significantly better than traditional imputation method (all t tests P<0..001), with the percentage reduction of the RMSE for accuracy and effect-size estimation that ranged from 12.4% to 17.3% and 19.8% to 32.9%, respectively. Conclusion: The combined approach significantly outperforms the traditional imputation algorithm. © 2013 American Society for Nutrition.

Ma X.,Tsinghua University | Fung C.-H.F.,University of Hong Kong | Razavi M.,University of Leeds
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

Measurement-device-independent quantum key distribution with a finite number of decoy states is analyzed under finite-data-size assumption. By accounting for statistical fluctuations in parameter estimation, we investigate vacuum+weak- and vacuum+two-weak-decoy-state protocols. In each case, we find proper operation regimes, where the performance of our system is comparable to the asymptotic case for which the key size and the number of decoy states approach infinity. Our results show that practical implementations of this scheme can be both secure and efficient. © 2012 American Physical Society.

Seneviratne C.J.,University of Hong Kong
The Chinese journal of dental research : the official journal of the Scientific Section of the Chinese Stomatological Association (CSA) | Year: 2011

Dental plaque is an archetypical biofilm composed of a complex microbial community. It is the aetiological agent for major dental diseases such as dental caries and periodontal disease. The clinical picture of these dental diseases is a net result of the cross-talk between the pathogenic dental plaque biofilm and the host tissue response. In the healthy state, both plaque biofilm and adjacent tissues maintain a delicate balance, establishing a harmonious relationship between the two. However, changes occur during the disease process that transform this 'healthy' dental plaque into a 'pathogenic' biofilm. Recent advances in molecular microbiology have improved the understanding of dental plaque biofilm and produced numerous clinical benefits. Therefore, it is imperative that clinicians keep abreast with these new developments in the field of dentistry. Better understanding of the molecular mechanisms behind dental diseases will facilitate the development of novel therapeutic strategies to establish a 'healthy dental plaque biofilm' by modulating both host and microbial factors. In this review, the present authors aim to summarise the current knowledge on dental plaque as a microbial biofilm and its properties in oral health and disease.

BACKGROUND: Populations in Asia are not only at risk of harm to their health through environmental degradation as a result of worsening pollution problems but also constantly threatened by recurring and emerging influenza epidemics and. pandemics. Situated in the area with the world's fastest growing economy and close to hypothetical epicenters of influenza transmission, Hong Kong offers a special opportunity for testing environmental management and public health surveillance in the region. In the Public Health and Air Pollution in Asia (PAPA*) project, the Hong Kong research team assessed the health effects of air pollution and influenza as well as the interaction between them. The team also assessed disparities in the health effects of air pollution between relatively deprived and more affluent areas in Hong Kong. The aim was to provide answers to outstanding research questions relating to the short-term effects of air pollution on mortality and hospital admissions; the health effects of influenza with a view to validating different measures of influenza activity according to virologic data; the confounding effects of influenza on estimates of the health effects of air pollution; the modifying effects of influenza on the health effects of air pollution; and the modifying effects of neighborhood social deprivation on the health effects of air pollution. DATA: Data on mortality and hospital admissions for all natural causes, as well as the subcategories of cardiovascular diseases (CVD) and respiratory diseases (RD), were derived from the Hong Kong Census and Statistics Department and the Hospital Authority. Daily concentrations of nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with an aerodynamic diameter < or = 10 pm (PM10); and ozone (O3) were derived from eight monitoring stations with hourly data that were at least 75% complete during the study period. Three measures of influenza and respiratory syncytial virus (RSV) activity were derived from positive isolates of specimens in the virology laboratory of Queen Mary Hospital (QMH), the main clinical teaching center at The University of Hong Kong and part of the Hong Kong Hospital Authority network of teaching hospitals: influenza intensity (defined as the weekly proportion of positive isolates of influenza in the total number of specimens received for diagnostic tests); the presence of influenza epidemic (defined as a period when the weekly frequency of these positive isolates is > or = 4% of the annual total number of positive isolates [i.e., twice the expected mean value] in two or more consecutive weeks); and influenza predominance (defined as a period of influenza epidemic when the weekly frequency of RSV was less than 2% for two or more consecutive weeks).

Li C.,University of Hong Kong | Guo L.,Institute of Systems Science
IEEE Transactions on Automatic Control | Year: 2011

In this technical note, we will investigate the maximum capability and limitations of the feedback mechanism in globally stabilizing a basic class of discrete-time nonlinearly parameterized dynamical systems with multiple unknown parameters. Both possibility and impossibility theorems together with a fairly complete characterization on the capability of feedback will be presented. It will be seen that to characterize the feedback capability, the growth rates of the sensitivity functions of the nonlinear dynamics with respect to the uncertain parameters play a crucial role, and a suitable decomposition of the family of the nonlinearly parameterized functions in question turns out to be necessary. © 2006 IEEE.

Pan H.,University of Hong Kong | Darvell B.W.,Kuwait University
Crystal Growth and Design | Year: 2010

Carbonate is present in biological apatites (BAp) (enamel, dentine, bone, and pathological calcifications) by substitution at phosphate and hydroxide sites, tending to increase its solubility in comparison with pure hydroxyapatite (HAp). The role of solution carbonate, however, is poorly understood. Using the solid titration method, it was found that the apparent solubility of HAp increased greatly with an increase in pCO2, and was sensitively-dependent at low values. No other phase was formed at the end point except HAp, and in particular no dicalcium phosphate dihydrate (DCPD) was found. However, no carbonate was detected in the end-point solid except for a small amount at pH ∼ 7.4, pCO2 = 0.01-1.0 bar. The implications of these results need further investigation, bearing as they do on a central topic in oral chemistry. © 2010 American Chemical Society.

Understanding environmental and biological influences on the dynamics of microbial communities has received great attention in microbial ecology. Here, utilizing large time-series 16S rRNA gene data, we show that in activated sludge of an environmentally important municipal wastewater treatment plant, 5-year temporal dynamics of bacterial community shows no significant seasonal succession, but is consistent with deterministic assemblage by taxonomic relatedness. Biological interactions are dominant drivers in determining the bacterial community assembly, whereas environmental conditions (mainly sludge retention time and inorganic nitrogen) partially explain phylogenetic and quantitative variances and indirectly influence bacterial assembly. We demonstrate a correlation-based statistical method to integrate bacterial association networks with their taxonomic affiliations to predict community-wide co-occurrence and co-exclusion patterns. The results show that although taxonomically closely related bacteria tend to positively co-occur (for example, out of a cooperative relationship), negative co-excluding correlations are deterministically observed between taxonomically less related species, probably implicating roles of competition in determining bacterial assembly. Overall, disclosures of the positive and negative species-species relations will improve our understanding of ecological niches occupied by unknown species and help to predict their biological functions in ecosystems.

Yeung W.L.,University of Hong Kong
Expert Systems with Applications | Year: 2011

Web services have emerged as the building blocks of a service-oriented architecture that supports not only enterprise application integration (EAI) and business process management (BPM) within an organization but also B2B collaboration based on business process integration. The web services choreography approach to B2B process integration allows business partners to orchestrate their own web services privately, while conforming with an agreed specification of the common ordering conditions and constraints under which messages are exchanged among partners' web services. In this approach, choreography conformance is an essential requirement for the successful implementation of collaborative processes. A formal approach to web services composition and conformance verification based on WS-CDL and WS-BPEL is presented. This approach involves model checking as an automated means of verifying choreography conformance. The main contributions include a precise notion of choreography conformance on which verification is based as well as support for the complementary use of visual modeling (e.g. UML) and standard WS-* notations in composition. © 2010 Elsevier Ltd. All rights reserved.

Liu X.,University of Pennsylvania | Jin D.-Y.,University of Hong Kong | McManus M.T.,University of California at San Francisco | Mourelatos Z.,University of Pennsylvania
Molecular Cell | Year: 2012

Assembly of microRNA ribonucleoproteins (miRNPs) or RNA-induced silencing complexes (RISCs) is essential for the function of miRNAs and initiates from processing of precursor miRNAs (pre-miRNAs) by Dicer or by Ago2. Here, we report an in vitro miRNP/RISC assembly assay programmed by pre-miRNAs from mammalian cell lysates. Combining in vivo studies in Dicer Knockout cells reconstituted with wild-type or catalytically inactive Dicer, we find that the miRNA loading complex (miRLC) is the primary machinery linking pre-miRNA processing to miRNA loading. We show that a miRNA precursor deposit complex (miPDC) plays a crucial role in Dicer-independent miRNA biogenesis and promotes miRNP assembly of certain Dicer-dependent miRNAs. Furthermore, we find that 5'-uridine, 3'-mid base pairing, and 5'-mid mismatches within pre-miRNAs promote their assembly into miPDC. Our studies provide a comprehensive view of miRNP/RISC assembly pathways in mammals, and our assay provides a versatile platform for further mechanistic dissection of such pathways in mammals. © 2012 Elsevier Inc.

Zhao G.,University of Hong Kong | Cawood P.A.,University of St. Andrews
Precambrian Research | Year: 2012

China contains three major Precambrian blocks, the North China, South China and Tarim cratons, separated and sutured by Phanerozoic orogenic belts. The North China Craton (NCC) contains rocks as old as 3.8Ga, but is dominated by Neoarchean igneous rocks that were formed during two magmatic events at 2.8-2.7Ga and 2.55-2.50Ga. The 2.8-2.7Ga magmatic pulse is considered as a major phase of juvenile crustal growth in the craton, though exposure of these rocks is limited. The 2.55-2.50Ga rocks make up ~80% of Archean basement in the NCC, but their rock associations, structural patterns, and metamorphic age and P-T paths in the eastern and western parts (Eastern and Western blocks) are different from those in the central part (Trans-North China Orogen). In the Eastern and Western blocks, the end-Neoarchean rocks are exposed as gneissic domes and dominated by tonalitic-trondhjemitic-granodioritic (TTG) gneisses and mafic to komatiitic rocks that were metamorphosed at ~2.5Ga, along anticlockwise P-T paths involving isobaric cooling, that is interpreted to reflect underplating of mantle-derived magmas. In the Trans-North China Orogen, the end-Neoarchean rocks occur as linear structural belts and are composed of arc-related granitoids and volcanic rocks that formed in a supra-subduction zone setting and were metamorphosed at ~1.85Ga along a clockwise P-T paths involving isothermal decompression in a continent-continent collisional setting. Although magmatic arc models can explain the origin of the 2.55-2.50Ga TTG rocks in the Eastern and Western blocks, a mantle plume model is favored because it best explains many other features, including the formation of komatiitic rocks. The 2.55-2.50Ga rocks and associated Paleoproterozoic rocks in the Trans-North China Orogen exhibit the same structural and metamorphic characteristics that typify continental margin arcs and collisional belts. Spatially, Paleoproterozoic rocks in the NCC are related to collisional assembly of the disparate parts of the Eastern and Western blocks including a ~1.95Ga collisional event that led to amalgamation of the Yinshan and Ordos blocks to form the Western Block, which then collided with the Eastern Block to form the Trans-North China Orogen at ~1.85Ga. Following the final assembly at ~1.85Ga, the interior of the NCC underwent on-going extension, leading to widespread emplacement of 1.80-1.75Ga mafic dyke swarms, 1.75-1.68Ga anorthosite-mangerite-granite-rapakivi suites, and deposition of Mesoproterozoic and Neoproterozoic strata. Meanwhile, a large Paleo-Mesoproterozoic volcanic belt (Xiong'er Group) developed on the southern margin of the NCC, and is variously interpreted as an intracontinental rift zone or an Andean-type continental margin arc. In the late Mesoproterozoic, the northern margin of the NCC underwent rifting (Zhaertai-Bayan Obo rift zone), coincident with breakup of the Columbia (Nuna) supercontinent.The South China Craton consists of the Yangtze and Cathaysia blocks, which are considered to have collided along the Jiangnan Belt in the Neoproterozoic. Archean and Paleoproterozoic basement rocks in the Yangtze Block are only locally exposed. The late Mesoproterozoic to early Neoproterozoic folded belts in the Yangtze Block are divided into the Jiangnan Belt in the southeast and the Panxi-Hannan Belt in the west and north. The former is dominated by early Neoproterozoic metamorphosed volcanic-sedimentary strata intruded by middle Neoproterozoic peraluminous (S-type) granites and unconformably overlain by the middle Neoproterozoic Banxi Group and its equivalents. The Panxi-Hannan Belt consists of late Mesoproterozoic to early Neoproterozoic metamorphosed volcanic-sedimentary units and plutonic complexes. A number of mutually exclusive models (e.g. plume-rift, slab-arc, plate-rift, etc.) have been proposed for these belts. The Cathaysia Block is composed predominantly of Neoproterozoic basement rocks with Paleoproterozoic rocks only exposed in southwest Zhejiang and north Fujian, and Mesoproterozoic rocks limited to Hainan Island. The Paleoproterozoic rocks consist of 1890-1830Ma granitoids and 1850-1815Ma supracrustal rocks, which were metamorphosed at 1.89-1.88Ga and locally reworked at 250-230Ma. Neoproterozoic rocks make up ~90% of the Precambrian basement in the Cathaysia Block and mainly consist of volcanic-sedimentary strata metamorphosed from greenschist to granulite facies. Some of the volcanic rocks have arc affinities, suggesting the existence of a Neoproterozoic magmatic arc in the Cathaysia Block. The Neoproterozoic rocks were metamorphosed at 460-420Ma. The tectonic setting of this event has been related to both intracontinental orogeny and continental margin subduction and collision.The Precambrian basement of the Tarim Craton consists of Neoarchean and Paleoproterozoic rocks and late Mesoproterozoic to early-middle Neoproterozoic sedimentary and volcanic strata metamorphosed at greenschist and blueschist facies, which are unconformably overlain by unmetamorphosed late Neoproterozoic (Sinian) cover. The Neoarchean and Paleoproterozoic rocks are exposed in the Kulukatage and Dunhuang complexes on the northern and northeastern margins of the craton, respectively. The Neoarchean rocks consist of granitoid rocks and minor supracrustal rocks, including TTG gneisses, calc-alkaline granites and Kf-granites, most of which were emplaced at 2.6-2.50Ga. The Paleoproterozoic basement rocks are also composed of granitoid and supracrustals rocks (Xingditage and Dunhuang groups), of which the granitoids were emplaced in two stages at 2.45-2.35Ga and ~1.9Ga. In the Kulukatage Complex, the Neoarchean and Paleoproterozoic rocks underwent metamorphic events at 1.9-1.8Ga and 1.1-1.0Ga that are related to assembly of the Columbia (Nuna) and Rodinia supercontinents, respectively. In the Dunhuang Complex, Archean rocks underwent metamorphic events at ~2.5Ga and 1.9-1.8Ga, similar to two major metamorphic events occurring in the Western Block of the NCC, leading to speculation that the complex is the western extension of the Alax Complex of the NCC. Late Mesoproterozoic to early-middle Neoproterozoic metamorphosed strata are exposed on the peripheral margins of the Tarim Craton and are considered to have formed in Andean-type continental margins that were deformed and metamorphosed between 1.0Ga and 0.9Ga, probably related to the assembly of Rodinia. During middle Neoproterozoic to Cambrian time, the Tarim Craton became a stable platform overlain by middle-late Neoproterozoic to Cambrian unmetamorphosed cover, of which the middle-late Neoproterozoic units contain four sequences of tillite correlated with the global snowball Earth events. Widespread middle to late Neoproterozoic ultramafic-mafic complexes and mafic dyke swarms with the Tarim Craton are related to a mantle plume event that led to the final breakup of Rodinia. © 2012 Elsevier B.V..

Gao X.L.,University of Hong Kong
Journal of Immigrant and Minority Health | Year: 2011

The impact of acculturation on systemic health has been extensively investigated and is regarded as an important explanatory factor for health disparity. However, information is limited and fragmented on the oral health implications of acculturation. This study aimed to review the current evidence on the oral health impact of acculturation. Papers were retrieved from five electronic databases. Twenty-seven studies were included in this review. Their scientific quality was rated and key findings were summarized. Seventeen studies investigated the impacts of acculturation on the utilization of dental services; among them, 16 reported positive associations betwen at least one acculturation indicator and use of dental services. All 15 studies relating acculturation to oral diseases (dental caries and periodontal disease) suggested better oral health among acculturated individuals. Evidence is lacking to support that better oral health of acculturated immigrants is attributable to their improved dental attendance. Further researches involving other oral health behaviors and diseases and incorporating refined acculturation scales are needed. Prospective studies will facilitate the understanding on the trajectory of immigrants' oral health along the acculturation continuum. © 2010 The Author(s).

Szeto W.Y.,University of Hong Kong
Transportation Research Part C: Emerging Technologies | Year: 2011

Traditionally, game-theoretic approaches to measuring transport network reliability have relied on the outcome of a game played between on the one hand users who seek minimum cost routes, and on the other hand, one or more evil entities or demons that seek to maximize the total expected network cost to the users by damaging links in the network. As the demons are assumed to be non-cooperative, this approach has been criticized that it cannot produce the worst-case solution for reliability analysis, contradicting the original purpose of adopting game-theoretic approaches. In this paper, two cooperative game formulations, the Stackelberg-Nash formulation and the partial-cooperative Nash formulation, are proposed to determine travel cost reliability. Their relationships are analyzed and their properties are examined. This paper also investigates under what condition(s) the classical non-cooperative demon behavior can lead to the worst-case solution. Numerical studies are provided to demonstrate: (i) the effects of the number of coalitions formed by demons on total network expected cost and network/Origin-Destination (OD) travel cost reliability; (ii) the paradoxical phenomenon that if one adds a road to a network then all the travelers may be worse off in terms of expected network travel cost and/or network travel cost reliability, and (iii) the possibility of the classical game-theoretic approach of overestimating network/OD travel cost reliability. © 2010 Elsevier Ltd.

Sun D.,University of Washington | Aivazian G.,University of Washington | Jones A.M.,University of Washington | Ross J.S.,University of Washington | And 3 more authors.
Nature Nanotechnology | Year: 2012

The combination of its high electron mobility, broadband absorption and ultrafast luminescence make graphene attractive for optoelectronic and photonic applications, including transparent electrodes, mode-locked lasers and high-speed optical modulators. Photo-excited carriers that have not cooled to the temperature of the graphene lattice are known as hot carriers, and may limit device speed and energy efficiency. However, their roles in charge and energy transport are not fully understood. Here, we use time-resolved scanning photocurrent microscopy to demonstrate that hot carriers, rather than phonons, dominate energy transport across a tunable graphene p-n junction excited by ultrafast laser pulses. The photocurrent response time varies from 1.5 ps at room temperature to 4 ps at 20 K, implying a fundamental bandwidth of ∼500 GHz (refs 12, 13, 21). Gate-dependent pump-probe measurements demonstrate that both thermoelectric and built-in electric field effects contribute to the photocurrent, with the contribution from each depending on the junction configuration. The photocurrent produced by a single pulsed laser also displays multiple polarity reversals as a function of carrier density, which is a possible signature of impact ionization. © 2012 Macmillan Publishers Limited. All rights reserved.

Si S.,University of Hong Kong | Tao D.,Nanyang Technological University | Geng B.,Peking University
IEEE Transactions on Knowledge and Data Engineering | Year: 2010

The regularization principals [31] lead approximation schemes to deal with various learning problems, e.g., the regularization of the norm in a reproducing kernel Hilbert space for the ill-posed problem. In this paper, we present a family of subspace learning algorithms based on a new form of regularization, which transfers the knowledge gained in training samples to testing samples. In particular, the new regularization minimizes the Bregman divergence between the distribution of training samples and that of testing samples in the selected subspace, so it boosts the performance when training and testing samples are not independent and identically distributed. To test the effectiveness of the proposed regularization, we introduce it to popular subspace learning algorithms, e.g., principal components analysis (PCA) for cross-domain face modeling; and Fisher's linear discriminant analysis (FLDA), locality preserving projections (LPP), marginal Fisher's analysis (MFA), and discriminative locality alignment (DLA) for cross-domain face recognition and text categorization. Finally, we present experimental evidence on both face image data sets and text data sets, suggesting that the proposed Bregman divergence-based regularization is effective to deal with cross-domain learning problems. © 2010 IEEE.

Ho C.S.H.,University of Hong Kong
Journal of Experimental Child Psychology | Year: 2010

This study examined how four domain-specific skills (arithmetic procedural skills, number fact retrieval, place value concept, and number sense) and two domain-general processing skills (working memory and processing speed) may account for Chinese children's mathematics learning difficulties. Children with mathematics difficulties (MD) of two age groups (7-8 and 9-11. years) were compared with age-matched typically achieving children. For both age groups, children with MD performed significantly worse than their age-matched controls on all of the domain-specific and domain-general measures. Further analyses revealed that the MD children with literacy difficulties (MD/RD group) performed the worst on all of the measures, whereas the MD-only group was significantly outperformed by the controls on the four domain-specific measures and verbal working memory. Stepwise discriminant analyses showed that both number fact retrieval and place value concept were significant factors differentiating the MD and non-MD children. To conclude, deficits in domain-specific skills, especially those of number fact retrieval and place value understanding, characterize the profile of Chinese children with MD. © 2010 Elsevier Inc.

Switzer A.D.,University of Hong Kong | Burston J.M.,University of Sydney
Geomorphology | Year: 2010

This study investigates the role of late Holocene sea-level change, large storms and possible pre-historic tsunami in the deposition of boulder features on an exposed headland and sheltered rock ramp. Large accumulations of boulders are found on coastal rock platforms, cliff tops and ramps in the Jervis Bay region of southeastern Australia. These deposits are elevated above sea-level and in places exhibit obvious signs of imbrication as a response to flow in a landward direction. The event history of these features is controversial and Holocene sea-level change, storms and tsunami can be considered as possible, non-mutually exclusive mechanisms of deposition. It is apparent that even if the detachment site, transport distance, elevation and final orientation of a boulder can be identified, deciphering the event history remains a difficult task. © 2009 Elsevier B.V. All rights reserved.

Wang M.,University of Hong Kong
Information Systems Frontiers | Year: 2011

E-learning is emerging as a popular approach of education in the workplace by virtue of its flexibility to access, just-in-time delivery, and cost-effectiveness. To improve social interaction and knowledge sharing in e-learning, Web 2.0 is increasingly utilized and integrated with e-learning applications. However, existing social learning systems fail to align learning with organizational goals and individual needs in a systemic way. The dominance of technology-oriented approaches makes elearning applications less goal-effective and poor in quality and design. To solve the problem, we address the requirement of integrating organizational, social, and individual perspectives in the development of Web 2.0 elearning systems. To fulfill the requirement, a key performance indicator (KPI)-oriented approach is presented in this study. By integrating a KPI model with Web 2.0 technologies, our approach is able to: 1) set up organizational goals and link the goals with expertise required for individuals; 2) build a knowledge network by linking learning resources to a set of competences to be developed and a group of people who learn and contribute to the knowledge network through knowledge creation, sharing, and peer evaluation; and 3) improve social networking and knowledge sharing by identifying each individual's work context, expertise, learning need, performance, and contribution. The mechanism of the approach is explored and elaborated with conceptual frameworks and implementation technologies. A prototype system for Web 2.0 e-learning has been developed to demonstrate the effectiveness of the approach. © Springer Science + Business Media, LLC 2009.

Lu W.,University of Hong Kong
Journal of Construction Engineering and Management | Year: 2010

Strength, weakness, opportunity, and threat (SWOT) analysis has been in use since the 1960s as a tool to assist strategic planning in various types of enterprises including those in the construction industry. While still widely used, the approach has called for improvements to make it more helpful in strategic management. The project described in this paper aimed to study whether the process to convert a SWOT analysis into a strategic plan could be assisted with some simple rationally quantitative model, as an augmented SWOT analysis. By using the mathematical approaches including the quantifying techniques, the "maximum subarray" method, and fuzzy mathematics, one or more heuristic rules (HRs) are derived from a SWOT analysis. These HRs bring into focus the most influential factors concerning a strategic planning situation, and thus inform strategic analysts where particular consideration should be given. A case study conducted in collaboration with a Chinese international construction company showed that the new SWOT approach is more helpful to strategic planners. The paper provides an augmented SWOT analysis approach for strategists to conduct strategic planning in the construction industry. It also contributes fresh insights into strategic planning by introducing rationally analytic processes to improve the SWOT analysis. © 2010 ASCE.

Ali J.R.,University of Hong Kong | Fitton J.G.,University of Edinburgh | Herzberg C.,Rutgers University
Journal of the Geological Society | Year: 2010

The Middle Permian (c. 262 Ma) Emeishan Basalt Formation of SW China is a commonly cited example of a large igneous province (LIP) that formed as a result of a deep-mantle plume impinging on the base of the lithosphere and generating large regional-scale up-doming prior to volcanism. Recently, however, this assertion has been challenged on the grounds that some lava flows close to the centre of the LIP were erupted in a submarine setting. Here we analyse all the available biolithostratigraphical, petrological, geochemical and volcanological information and show that this supports the idea that the terrain was generated by a plume that originated in the mantle. Emeishan basalt magma melted from a hot mantle source with trace element contents that are similar to the source of Icelandic and intraplate ocean island basalts. However, the amount and lateral extent of uplift is significantly less than is predicted by conventional deepmantle plume models. We conclude that large-scale doming is not a diagnostic feature of mantle plumes; surface topography can be greatly influenced by the type of lower mantle plume (thermal or thermochemical), how it passes through the transition zone, and how it interacts with the lithosphere. © 2010 Geological Society of London.

Hou J.,CAS Institute of Tibetan Plateau Research | D'Andrea W.J.,Lamont Doherty Earth Observatory | Liu Z.,University of Hong Kong
Quaternary Science Reviews | Year: 2012

There is a great deal of controversy regarding the fate of glaciers and ice fields on the Tibetan Plateau in the face of continued anthropogenic global warming. Paleoclimate reconstructions and spatial analyses aimed at mapping past climate changes are the key to understanding the climatic response of the Tibetan Plateau to changing conditions. Specifically, the numerous lakes distributed across the Tibetan Plateau can provide high-resolution (spatial and temporal) climate reconstructions to investigate past changes in the climate system. In this paper, we review the primary limitation to exploiting these valuable paleoclimate archives: errors in radiocarbon-based age models. We review the techniques that have been used to estimate 14C reservoir ages on the Tibetan Plateau and compile the published 14C reservoir ages to examine their spatial and temporal patterns and to assess the imposed chronological uncertainties. Using site-specific evaluations of Bangong Co and Lake Qinghai, we demonstrate that 14C age model uncertainties permit equally probable and contrasting interpretations of existing paleoclimate records. We also examine 14C-induced uncertainties in the spatial climatic response on the Tibetan Plateau to (1) the termination of the Last Glacial Maximum and (2) the Holocene Thermal Maximum. We conclude with recommendations for reducing uncertainties in future lake-based paleoclimate studies on the Tibetan Plateau. © 2012 Elsevier Ltd.

Lee M.-C.,Harvard University | Lee M.-C.,University of Hong Kong | Marx C.J.,Harvard University
PLoS Genetics | Year: 2012

Genome reduction has been observed in many bacterial lineages that have adapted to specialized environments. The extreme genome degradation seen for obligate pathogens and symbionts appears to be dominated by genetic drift. In contrast, for free-living organisms with reduced genomes, the dominant force is proposed to be direct selection for smaller, streamlined genomes. Most variation in gene content for these free-living species is of "accessory" genes, which are commonly gained as large chromosomal islands that are adaptive for specialized traits such as pathogenicity. It is generally unclear, however, whether the process of accessory gene loss is largely driven by drift or selection. Here we demonstrate that selection for gene loss, and not a shortened genome, per se, drove massive, rapid reduction of accessory genes. In just 1,500 generations of experimental evolution, 80% of populations of Methylobacterium extorquens AM1 experienced nearly parallel deletions removing up to 10% of the genome from a megaplasmid present in this strain. The absence of these deletion events in a mutation accumulation experiment suggested that selection, rather than drift, has dominated the process. Reconstructing these deletions confirmed that they were beneficial in their selective regimes, but led to decreased performance in alternative environments. These results indicate that selection can be crucial in eliminating unnecessary genes during the early stages of adaptation to a specialized environment. © 2012 Lee, Marx.

Lemke K.H.,University of Hong Kong
Current Organic Chemistry | Year: 2013

Hydrothermal fluids play a major role in the transport and redistribution of inorganic and organic compounds in the Earth's crust. The unique physico-chemical properties of water at these conditions have demonstrated to facilitate a wide range of novel chemical synthesis and biomass conversion processes, but have also attracted much attention because organic synthesis reactions at elevated temperatures may have contributed towards the origin of life. This short review focuses on the high-temperature stability of aqueous biomolecules. In particular, a review of individual bond breaking reactions in amino acids, nucleosides and nucleotides is presented and corresponding reactions rates and their temperature- and pH-dependence are reported and discussed. © 2013 Bentham Science Publishers.

De Mitcheson Y.S.,University of Hong Kong
BioScience | Year: 2016

Many marine fishes mate in massive and spectacular gatherings at predictable times and places. These spawning aggregations are often attractive targets of fisheries. Many commercially important fish species exhibit aggregation spawning, and many have undergone serious declines from overfishing. It is timely to explore whether the exploitation of spawning aggregations makes species particularly susceptible to overfishing; if so, why and how we can better manage these species. I present evidence that aggregate fish spawners are especially vulnerable because of both increased catchability (lethal effects) and biological factors (nonlethal effects). For these species to continue contributing to food security and livelihoods while retaining their ecosystem function, a truly precautionary approach is essential to reduce the risk of declines, particularly in the case of small-scale commercial fisheries of low-productivity species and where management and monitoring are lacking. There is a pressing need to mainstream spawning aggregations into marine resource management. © 2016 The Author(s).

Ali J.R.,University of Hong Kong | Aitchison J.C.,University of Sydney
Basin Research | Year: 2014

Greater India's northern edge prior to collision with Asia is typically modelled as a rifted passive margin. We argue for a quite different geometry as a consequence of two tectonic episodes that happened sometime before the main impact. Whilst the western segment of India's northern boundary had formed in the Late Triassic as a rifted margin, the central and eastern portions developed between 132 and 110 Ma when the sub-continent separated from Australia-Antarctica as the inner wall of a dextral 'scything' transform fault along the Wallaby-Zenith Fracture Zone off western Australia. Key features would have been (i) the very narrow (20-30 km wide) ocean-continent transition zone marking the sub-continent's eastern northern boundary, and (ii) similar to the region offshore South Africa's Garden Route coast, Greater India's NE corner may have developed a series of 'perched' half grabens due to shearing related to its motion along the Wallaby-Zenith Fracture Zone, from initial break-up until it passed the Zenith Plateau (ca. 110 Ma). Differences in the development of NW Greater India may be reflected in restriction of ultra-high pressure metamorphic rocks to the western Himalaya where late Paleocene subduction of the rifted passive margin occurred at sub-equatorial latitudes beneath the intra-Tethyan arc. Further east, where the margin developed along the scything transform, the continent-ocean boundary would have been more abrupt and probably less strongly welded. Ophiolite emplacement appears to have been penecontemporaneous along the margin. A subsequent slab break-off episode then eliminated the original plate boundary. Thereafter, remaining oceanic lithosphere north of the arc sutured to the sub-continent, albeit rather weakly, was consumed beneath Eurasia, culminating in India-Asia collision. © 2014 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.

Cheung J.P.,University of Hong Kong
Journal of orthopaedic surgery (Hong Kong) | Year: 2012

To review records of 166 patients who underwent treatment for Mycobacterium marinum tenosynovitis of the hand and wrist to identify factors associated with functional outcome. Records of 97 men and 69 women aged 13 to 85 (mean, 50) years who underwent treatment for suspected M marinum tenosynovitis of the hand and wrist were retrospectively reviewed. All underwent open biopsy; synovectomy was performed when florid synovitis was present. Rifampicin and ethambutol were usually prescribed. Clarithromycin, minocycline and/or levofloxacin were used as adjuvants if there was drug intolerance, allergy, or relapse. The duration of antibiotic treatment depended on the clinical recovery. Patients were followed up for one year after completion of drug treatment. Functional outcome was considered excellent for those with >195o total active motion (TAM) and >75% return of motion, good for those with 130o to 195o TAM and 50 to 75% return of motion, fair for those with 65o to 129o TAM and 25 to 49% return of motion, and poor for those with<65o TAM and <25% return of motion. The mean delay in presentation was 4.9 (0.3-120) months. 93 of the patients presented with disabilities (flexion deformity or reduced range of motion), 64 of whom presented one month after injury. 37 (22%) of the patients had received intralesional steroids prior to admission, 30 of whom presented one month after injury. 32 (19%) patients were treated with antibiotics alone, whereas 134 (81%) patients underwent debridement in addition to antibiotic treatment. The mean duration of antibiotic treatment was 7.2 (range, 0-29) months. Of the 156 patients who completed the follow-up, functional outcome was satisfactory in 128 (82%) and unsatisfactory in 28 (17%). Steroid injections and late presentation led to worse functional outcome. Patients with unsatisfactory outcome were more likely to have received intralesional steroid injections (43% [16/37] vs. 10% [12/118], p<0.001, Pearson Chi squared test), have presented >2 months after injury (27% [21/79] vs. 9% [7/77], p=0.004, Pearson Chi squared test), and have undergone synovectomy (23% [28/124]) vs. 0% [0/32], p=0.001, Fisher's exact test). Worse functional outcome correlated with late presentation (r=0.218) and the greater number of debridement procedures (r=0.453). Delayed antibiotic treatment of M marinum infections and steroid injections were associated with unsatisfactory outcome. Clinicians must have a high index of suspicion for this condition and avoid inappropriate management such as intralesional steroid injections. Public awareness to this condition should be raised.

Niu J.,University of Hong Kong
Stochastic Environmental Research and Risk Assessment | Year: 2013

This study examines the temporal patterns of precipitation and the influence of large-scale climate anomalies in the Pearl River basin (South China), with particular focus on sub-basin scale. Three popular data analysis techniques are employed: (1) wavelet analysis; (2) principal component analysis (PCA); and (3) rank correlation method. With due consideration to hydrologic factors, water resources activities, and large-scale climate data, the entire basin is divided into ten sub-basins and the analysis is performed on monthly data. The wavelet analysis reveals discernible differences in temporal scales of fluctuation embedded in the monthly precipitation anomalies over the basin. The PCA delineates three coherent regions exhibiting similar distribution of variability across scales. Analysis of linkages between precipitation and teleconnection patterns using cross-wavelet transform and wavelet coherence reveals that the dominant variabilities of precipitation are essentially depicted by the Indian Ocean Dipole (IOD), especially for the central and eastern part of the Pearl River basin. On the influence of El Niño-Southern Oscillation (ENSO) signal on precipitation, more significant correlation is detected for the eastern part of the basin, long-term relationships (within 4-8 years band) are found for the western part of the basin, while the central part seems to be acting as a transition zone. Rank correlations of scale-averaged wavelet power between regional precipitation and climate indices for the dominant low-frequency variability band (0.84-8.40 years) provide further support to the different precipitation-climate relationships for different regions over the basin. The present results provide valuable information towards: (1) improving predictions of extreme hydroclimatic events in the Pearl River basin, based on their relationships with IOD or ENSO; and (2) devising better adaptation and mitigation strategies under a future changing climate. © 2012 Springer-Verlag Berlin Heidelberg.

Huang K.,University of Hong Kong | Larsson E.,Linkoping University
IEEE Transactions on Signal Processing | Year: 2013

Far-field microwave power transfer (MPT) will free wireless sensors and other mobile devices from the constraints imposed by finite battery capacities. Integrating MPT with wireless communications to support simultaneous wireless information and power transfer (SWIPT) allows the same spectrum to be used for dual purposes without compromising the quality of service. A novel approach is presented in this paper for realizing SWIPT in a broadband system where orthogonal frequency division multiplexing and transmit beamforming are deployed to create a set of parallel sub-channels for SWIPT, which simplifies resource allocation. Based on a proposed reconfigurable mobile architecture, different system configurations are considered by combining single-user/multi-user systems, downlink/uplink information transfer, and variable/fixed coding rates. Optimizing the power control for these configurations results in a new class of multi-user power-control problems featuring the circuit-power constraints, specifying that the transferred power must be sufficiently large to support the operation of the receiver circuitry. Solving these problems gives a set of power-control algorithms that exploit channel diversity in frequency for simultaneously enhancing the throughput and the MPT efficiency. For the system configurations with variable coding rates, the algorithms are variants of water-filling that account for the circuit-power constraints. The optimal algorithms for those configurations with fixed coding rates are shown to sequentially allocate mobiles their required power for decoding in ascending order until the entire budgeted power is spent. The required power for a mobile is derived as simple functions of the minimum signal-to-noise ratio for correct decoding, the circuit power and sub-channel gains. © 1991-2012 IEEE.

Wong C.M.,University of Hong Kong
Research report (Health Effects Institute) | Year: 2012

After the implementation of a regulation restricting sulfur to 0.5% by weight in fuel on July 1, 1990, in Hong Kong, sulfur dioxide (SO2*) levels fell by 45% on average and as much as 80% in the most polluted districts (Hedley et al. 2002). In addition, a reduction of respiratory symptoms and an improvement in bronchial hyperresponsiveness in children were observed (Peters et al. 1996; Wong et al. 1998). A recent time-series study (Hedley et al. 2002) found an immediate reduction in mortality during the cool season at six months after the intervention, followed by an increase in cool-season mortality in the second and third years, suggesting that the reduction in pollution was associated with a delay in mortality. Proportional changes in mortality trends between the 5-year periods before and after the intervention were measured as relative risks and used to assess gains in life expectancy using the life table method (Hedley et al. 2002). To further explore the relation between changes in pollution-related mortality before and after the intervention, our study had three objectives: (1) to evaluate the short-term effects on mortality of changes in the pollutant mix after the Hong Kong sulfur intervention, particularly with changes in the particulate matter (PM) chemical species; (2) to improve the methodology for assessment of the health impact in terms of changes in life expectancy using linear regression models; and (3) to develop an approach for analyzing changes in life expectancy from Poisson regression models. A fourth overarching objective was to determine the relation between short- and long-term benefits due to an improvement in air quality. For an assessment of the short-term effects on mortality due to changes in the pollutant mix, we developed Poisson regression Core Models with natural spline smoothers to control for long-term and seasonal confounding variations in the mortality counts and with covariates to adjust for temperature (T) and relative humidity (RH). We assessed the adequacy of the Core Models by evaluating the results against the Akaike Information Criterion, which stipulates that, at a minimum, partial autocorrelation plots should be between -0.1 and 0.1, and by examining the residual plots to make sure they were free from patterns. We assessed the effects for gaseous pollutants (NO2, SO2, and O3), PM with an aerodynamic diameter < or = 10 microm (PM10), and its chemical species (aluminum [Al], iron [Fe], manganese [Mn], nickel [Ni], vanadium [V], lead [Pb], and zinc [Zn]) using the Core Models, which were developed for the periods 5 years (or 2 years in the case of the sensitivity analysis) before and 5 years after the intervention, as well as in the10-year (or 7-year in the case of the sensitivity analysis) period pre- and post-intervention. We also included an indicator to separate the pre- and post-intervention periods, as well as the product of the indicator with an air pollution concentration variable. The health outcomes were mortality for all natural causes and for cardiovascular and respiratory causes, at all ages and in the 65 years or older age group. To assess the short- and long-term effects, we developed two methods: one using linear regression models reflecting the age-standardized mortality rate D(j) at day j, divided by a reference D(ref); and the other using Poisson regression models with daily mortality counts as the outcome variables. We also used both models to evaluate the relation between outcome variables and daily air pollution concentrations in the current day up to all previous days in the past 3 to 4 years. In the linear regression approach, we adjusted the data for temperature and relative humidity. We then removed season as a potential confounder, or deseasonalized them, by calculating a standard seasonal mortality rate profile, normalized to an annual average of unity, and dividing the mortality rates by this profile. Finally, to correct for long-term trends, we calculated a reference mortality rate D(ref)(j) as a moving average of the corrected and deseasonalized D(j) over the observation window. Then we regressed the outcome variable D(j)/D(ref) on an entire exposure sequence {c(i)} with lags up to 4 years in order to obtain impact coefficient f(i) from the regression model shown below: deltaD(j)/D (ref) = i(max)sigma f(i) c(j - i)(i = 0). The change in life expectancy (LE) for a change of units (deltac) in the concentration of pollutants on T(day)--representing the short interval (i.e., a day)--was calculated from the following equation (deltaL(pop) = average loss in life expectancy of an entire population): deltaL(pop) = -deltac T(day) infinity sigma (j = 0) infinity sigma f(i) (i = 0). In the Poisson regression approach, we fitted a distributed-lag model for exposure to previous days of up to 4 years in order to obtain the cumulative lag effect sigma beta(i). We fit the linear regression model of log(LE*/LE) = gamma(SMR - 1) + alpha to estimate the parameter gamma by gamma, where LE* and LE are life expectancy for an exposed and an unexposed population, respectively, and SMR represents the standardized mortality ratio. The life expectancy change per Ac increase in concentration is LE {exp[gamma delta c(sigma beta(i))]-1}. In our assessment of the changes in pollutant levels, the mean levels of SO2, Ni, and V showed a statistically significant decline, particularly in industrial areas. Ni and V showed the greatest impact on mortality, especially for respiratory diseases in the 5-year pre-intervention period for both the all-ages and 65+ groups among all chemical species. There were decreases in excess risks associated with Ni and V after the intervention, but they were nonsignificant. Using the linear regression approach, with a window of 1095 days (3 years), the losses in life expectancy with a 10-microg/m3 increase in concentrations, using two methods of estimation (one with adjustment for temperature and RH before the regression against pollutants, the other with adjustment for temperature and RH within the regression against pollutants), were 19.2 days (95% CI, 12.5 to 25.9) and 31.4 days (95% CI, 25.6 to 37.2) for PM10; and 19.7 days (95% CI, 15.2 to 24.2) and 12.8 days (95% CI, 8.9 to 16.8) for SO2. The losses in life expectancy in the current study were smaller than the ones implied by Elliott and colleagues (2007) and Pope and colleagues (2002) as expected since the observation window in our study was only 3 years whereas these other studies had windows of 16 years. In particular, the coefficients used by Elliott and colleagues (2007) for windows of 12 and 16 years were non-zero, which suggests that our window of at most 3 years cannot capture the full life expectancy loss and the effects were most likely underestimated. Using the Poisson regression approach, with a window of 1461 days (4 years), we found that a 10-microg/m3 increase in concentration of PM10 was associated with a change in life expectancy of -69 days (95% CI, -140 to 1) and a change of -133 days (95% CI, -172 to -94) for the same increase in SO2. The effect estimates varied as expected according to most variations in the sensitivity analysis model, specifically in terms of the Core Model definition, exposure windows, constraint of the lag effect pattern, and adjustment for smoking prevalence or socioeconomic status. Our results on the excess risks of mortality showed exposure to chemical species to be a health hazard. However, the statistical power was not sufficient to detect the differences between the pre- and post-intervention periods in Hong Kong due to the data limitations (specifically, the chemical species data were available only once every 6 days, and data were not available from some monitoring stations). Further work is needed to develop methods for maximizing the information from the data in order to assess any changes in effects due to the intervention. With complete daily air pollution and mortality data over a long period, time-series analysis methods can be applied to assess the short- and long-term effects of air pollution, in terms of changes in life expectancy. Further work is warranted to assess the duration and pattern of the health effects from an air pollution pulse (i.e., an episode of a rapid rise in air pollution) so as to determine an appropriate length and constraint on the distributed-lag assessment model.

Xu L.,University of Hong Kong
American journal of human biology : the official journal of the Human Biology Council | Year: 2014

Previous small studies examining differences in testosterone concentrations by ethnicity found mixed results for Caucasians and Chinese men, which might be confounded by age differences and living standards. The aim of the present study is to examine the differences in total, free, and bioavailable testosterone concentrations between healthy young men from the United States (US) and from the most economically developed part of China, i.e., Hong Kong (HK). Cross-sectional analysis based on 365 young men from the Third National Health and Nutrition examination Survey (NHANES III) in the US and 299 Chinese men recruited from university students. All participants were aged from 18 to 29 years. Main outcome measures were total testosterone (TT) and calculated bioavailable testosterone (Bio T) and free testosterone (FT). In both US and Chinese men, TT, FT, and Bio T concentration peaked at 20-24 years of age, at 23.19, 0.49, and 12.23 nmol/l in US men, and 20.72, 0.48 and 12.59 nmol/l in Chinese men, respectively. Among those aged 18-24 years, after adjusting for age, US men had higher TT (mean, 95% confidence interval: 21.64, 21.31-21.99 versus 20.20, 20.12-20.28 nmol/l), but not FT (0.47, 0.47-0.48 versus 0.47, 0.47-0.47 nmol/l) or Bio T (11.90, 11.83-11.97 versus 12.39, 12.35-12.42 nmol/l) than Chinese men. TT, but not FT or Bio T concentrations are lower in young healthy Chinese men than US men. These differences apparent in young men may be important in understanding different patterns of diseases between Western and Asian populations. Copyright © 2013 Wiley Periodicals, Inc.

Ma W.W.K.,Hong Kong Shue Yan University | Chan A.,University of Hong Kong
Computers in Human Behavior | Year: 2014

Social media, such as Facebook and Twitter, have become extremely popular. Facebook, for example, has more than a billion registered users and thousands of millions of units of information are shared every day, including short phrases, articles, photos, and audio and video clips. However, only a tiny proportion of these sharing units trigger any type of knowledge exchange that is ultimately beneficial to the users. This study draws on the theory of belonging and the intrinsic motivation of altruism to explore the factors contributing to knowledge sharing behavior. Using a survey of 299 high school students applying for university after the release of the public examination results, we find that perceived online attachment motivation (β = 0.31, p < 0.001) and perceived online relationship commitment (β = 0.49, p < 0.001) have positive, direct, and significant effects on online knowledge sharing (R 2 0.568). Moreover, when introduced into the model, altruism has a direct and significant effect on online knowledge sharing (β = 0.46, p < 0.001) and the total variance explained by the extended model increases to 64.9%. The implications of the findings are discussed. © 2014 Elsevier Ltd. All rights reserved.

Harko T.,University of Hong Kong
Journal of Cosmology and Astroparticle Physics | Year: 2011

We analyze the observed properties of dwarf galaxies, which are dark matter dominated astrophysical objects, by assuming that dark matter is in the form of a strongly-coupled, dilute Bose-Einstein condensate. The basic astrophysical properties of the condensate (density profile, rotational velocity, and mass profile, respectively), are derived from a variational principle. To test the validity of the model we compare first the tangential velocity equation of the model with a sample of eight rotation curves of dwarf galaxies. We find a good agreement between the theoretically predicted rotation curves (without any baryonic component) and the observational data. The mean value of the logarithmic inner slope of the mass density profile of dwarf galaxies is also obtained, and it is shown that the observed value of this parameter is in agreement with the theoretical results. The predictions of the Bose-Einstein condensate model are also systematically compared with the predictions of the standard Cold Dark Matter model. The non-singular density profiles of the Bose-Einstein condensed dark matter generally show the presence of an extended core, whose presence is due to the strong interaction between dark matter particles. © 2011 IOP Publishing Ltd and SISSA.

Young B.,University of Hong Kong | Ellobody E.,Tanta University
Engineering Structures | Year: 2011

The structural performance of axially restrained concrete encased steel composite columns at elevated temperatures is investigated in this study. An efficient nonlinear 3-D finite element model was presented for the analysis of the pin-ended axially loaded columns. The restraint ratios varied from 20% to 100% of the axial stiffness of the composite columns at ambient temperature. The finite element model was verified against published test results on axially restrained concrete encased steel composite columns at elevated temperatures. The columns investigated had different cross-sectional dimensions, different coarse aggregates and different load ratios during fire. The nonlinear material properties of steel, concrete, longitudinal and transverse reinforcement bars as well as the effect of concrete confinement at ambient and elevated temperatures were considered in the finite element model. The interface between the steel section and concrete, the longitudinal and transverse reinforcement bars, and the reinforcement bars and concrete were also considered allowing the bond behaviour to be modelled and the different components to retain its profile during the deformation of the column. The initial overall geometric imperfection was carefully included in the model. The time-temperature relationships, deformed shapes at failure, time-axial displacement relationships, failure modes and fire resistances of the columns were evaluated by the finite element model and compared well against test results. Furthermore, the variables that influence the fire resistance and behaviour of the axially restrained composite columns comprising different axial restraint ratios, different load ratios during fire, different coarse aggregates and different slenderness ratios were investigated in a parametric study. It is shown that axially restrained composite columns behave differently in fire compared to the unrestrained columns since the typical "runaway" failure was not predicted from the finite element analysis. The fire resistances of the composite columns obtained from the finite element analysis were compared with the design values obtained from the Eurocode 4 for composite columns at elevated temperatures. It is shown that the EC4 is generally conservative for all the axially restrained concrete encased steel composite columns, except for some columns with higher load and slenderness ratios. © 2010 Elsevier Ltd.

Interpreting the genetic variants located in the regulatory regions, such as enhancers and promoters, is an indispensable step to understand molecular mechanism of complex traits. Recent studies show that genetic variants detected by genome-wide association study (GWAS) are significantly enriched in the regulatory regions. Therefore, detecting, annotating and prioritizing of genetic variants affecting gene regulation are critical to our understanding of genotype-phenotype relationships. Here, we developed a web server GWAS3D to systematically analyze the genetic variants that could affect regulatory elements, by integrating annotations from cell type-specific chromatin states, epigenetic modifications, sequence motifs and cross-species conservation. The regulatory elements are inferred from the genome-wide chromosome interaction data, chromatin marks in 16 different cell types and 73 regulatory factors motifs from the Encyclopedia of DNA Element project. Furthermore, we used these function elements, as well as risk haplotype, binding affinity, conservation and P-values reported from the original GWAS to reprioritize the genetic variants. Using studies from low-density lipoprotein cholesterol, we demonstrated that our reprioritizing approach was effective and cell type specific. In conclusion, GWAS3D provides a comprehensive annotation and visualization tool to help users interpreting their results. The web server is freely available at http://jjwanglab.org/gwas3d.

Cheung Y.-F.,University of Hong Kong
Korean Circulation Journal | Year: 2014

Significant improvement in survival of children with congenital cardiac malformations has resulted in an increasing population of adolescent and adult patients with congenital heart disease. Of the long-term cardiac problems, ventricular dysfunction remains an important issue of concern. Despite corrective or palliative repair of congenital heart lesions, the right ventricle, which may be the subpulmonary or systemic ventricular chamber, and the functional single ventricle are particularly vulnerable to functional impairment. Regular assessment of cardiac function constitutes an important aspect in the long-term follow up of patients with congenital heart disease. Echocardiography remains the most useful imaging modality for longitudinal monitoring of cardiac function. Conventional echocardiographic assessment has focused primarily on quantification of changes in ventricular size and blood flow velocities during the cardiac cycles. Advances in echocardiographic technologies including tissue Doppler imaging and speckle tracking echocardiography have enabled direct interrogation of myocardial deformation. In this review, the issues of ventricular dysfunction in congenital heart disease, conventional echocardiographic and novel myocardial deformation imaging techniques, and clinical applications of these techniques in the functional assessment of congenital heart disease are discussed Copyright ©2014 The Korean Society of Cardiology.

Yam V.W.-W.,University of Hong Kong
Angewandte Chemie - International Edition | Year: 2015

Inorganic chemistry has evolved from fundamental studies to the forefronts of interdisciplinary research. What was considered to be impossible or elusive has now become feasible. While we still keep our identity as inorganic chemists, the sharp demarcation between the divisions of different subject disciplines or subdisciplines is no longer relevant Read more in the Editorial by Vivian W.-W. Yam. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zeng H.,Chinese University of Hong Kong | Cui X.,University of Hong Kong
Chemical Society Reviews | Year: 2015

The ultimate goal of making atomically thin electronic devices stimulates intensive research on layered materials, in particular the group-VI transition metal dichalcogenides (TMDs). Atomically thin group-VI TMD crystals with a 2H stacking order emerging as a family of intrinsic 2-dimensional (2D) semiconductors with a sizeable bandgap in the visible and near infrared range satisfy numerous requirements for ultimate electronics and optoelectronics. In addition, the characteristic inversion symmetry breaking presented in monolayer TMDs leads to non-zero but contrasting Berry curvatures and orbit magnetic moments at K/K′ valleys located at the corners of the first Brillouin zone. These features provide an opportunity to manipulate electrons' additional internal degrees of freedom, namely the valley degree of freedom, making monolayer TMDs a promising candidate for the conceptual valleytronics. Besides, the strong spin-orbit interactions and the subsequent spin-valley coupling demonstrated in atomically thin group-VI TMDs open up potential routes towards quantum manipulation. In this tutorial review, we highlight recent advances in the optical study on electronic structures, vibrational properties, excitonic effects, valley dependent optical selection rules, and the interplay of valley, spin, and layer degrees of freedoms in this class of atomic 2D semiconductors including MoS2, MoSe2, WS2, and WSe2. © 2015 The Royal Society of Chemistry.

Lee H.C.,University of Hong Kong
Science China Life Sciences | Year: 2011

The concept advanced by Berridge and colleagues that intracellular Ca 2+-stores can be mobilized in an agonist-dependent and messenger (IP 3)-mediated manner has put Ca 2+-mobilization at the center stage of signal transduction mechanisms. During the late 1980s, we showed that Ca 2+-stores can be mobilized by two other messengers unrelated to inositol trisphosphate (IP 3) and identified them as cyclic ADP-ribose (cADPR), a novel cyclic nucleotide from NAD, and nicotinic acid adenine dinucleotide phosphate (NAADP), a linear metabolite of NADP. Their messenger functions have now been documented in a wide range of systems spanning three biological kingdoms. Accumulated evidence indicates that the target of cADPR is the ryanodine receptor in the sarco/endoplasmic reticulum, while that of NAADP is the two pore channel in endolysosomes. As cADPR and NAADP are structurally and functionally distinct, it is remarkable that they are synthesized by the same enzyme. They are thus fraternal twin messengers. We first identified the Aplysia ADP-ribosyl cyclase as one such enzyme and, through homology, found its mammalian homolog, CD38. Gene knockout in mice confirms the important roles of CD38 in diverse physiological functions from insulin secretion, susceptibility to bacterial infection, to social behavior of mice through modulating neuronal oxytocin secretion. We have elucidated the catalytic mechanisms of the Aplysia cyclase and CD38 to atomic resolution by crystallography and site-directed mutagenesis. This article gives a historical account of the cADPR/NAADP/CD38-signaling pathway and describes current efforts in elucidating the structure and function of its components. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Churchill D.,University of Hong Kong
Educational Technology and Society | Year: 2011

This article presents recommendations for the design of conceptual models for applications via handheld devices such as personal digital assistants and some mobile phones. The recommendations were developed over a number of years through experience that involves design of conceptual models, and applications of these multimedia representations with students in schools and higher education. Three sets of design recommendations are discussed: design presentation of conceptual models, small screen design, and design in relation to specific learning uses. These recommendations should prove useful to designers of multimedia resources and professionals engaged in instructional uses of these representations. The article calls for researchers to pay more attention to the design of conceptual models and other forms of multimedia resources and their instructional uses. © International Forum of Educational Technology & Society (IFETS).

Chan C.K.Y.,University of Hong Kong
European Journal of Engineering Education | Year: 2012

Experiential learning pedagogy is taking a lead in the development of graduate attributes and educational aims as these are of prime importance for society. This paper shows a community service experiential project conducted in China. The project enabled students to serve the affected community in a post-earthquake area by applying their knowledge and skills. This paper documented the students' learning process from their project goals, pre-trip preparations, work progress, obstacles encountered to the final results and reflections. Using the data gathered from a focus group interview approach, the four components of Kolb's learning cycle, the concrete experience, reflection observation, abstract conceptualisation and active experimentation, have been shown to transform and internalise student's learning experience, achieving a variety of learning outcomes. The author will also explore how this community service type of experiential learning in the engineering discipline allowed students to experience deep learning and develop their graduate attributes. © 2012 Copyright Taylor and Francis Group, LLC.

Saunders R.M.K.,University of Hong Kong
Botanical Journal of the Linnean Society | Year: 2012

The pollination biology of Annonaceae has received considerable attention, with data now available for >45% of the genera (or genus-equivalent clades) included in recent molecular phylogenetic analyses. This provides a basis for understanding evolutionary shifts in the pollination system within the family. The present study focuses on subfamilies Anaxagoreoideae, Ambavioideae and Annonoideae, for which robust, well-resolved phylogenetic trees are available. Information is summarized on the pollination biology of individual clades and the evolutionary adaptations favouring different pollinator guilds evaluated. Although the majority of species of Annonaceae are pollinated by small beetles, five other pollinator groups are known: large beetles, thrips, flies, bees and cockroaches. Small-beetle pollination is inferred as the ancestral pollination system, with all other systems being derived. Evolutionary shifts to pollination by large beetles, thrips and flies are unlikely to have been significantly constrained by previous adaptations favouring pollination by small beetles, as many of the adaptations to these different pollinator guilds are similar (including protogyny, partially enclosed floral chambers and olfactory cues). In contrast, however, the evolutionary shift to bee pollination has presumably been constrained by both protogyny (as pollen-collecting bees are unlikely to visit pistillate-phase flowers) and the presence of floral chambers. © 2012 The Linnean Society of London.

Chan C.K.Y.,University of Hong Kong
European Journal of Engineering Education | Year: 2012

While experential learning has been increasingly explored and adopted by higher education institutions, few have researched the appropriate assessment methods that can be aligned with the learning outcomes of experential learning. A literature review on the diverse forms of assessment currently used for community service types of experiential learning in higher education is presented in this paper to review their appropriateness in assessing experential learning. The paper also describes the assessment framework of the University of Hong Kong Sichuan Reconstruction Community Service Project, which is incorporated into a multidisciplinary community service learning project. Feedback from students and teachers are reviewed to gauge their preferences towards these assessments, as well as their opinions on assigning academic credits to experential learning projects. © 2012 SEFI.

Miao Q.,Chinese University of Hong Kong | Miao Q.,University of Hong Kong
Advanced Materials | Year: 2014

Introducing N atoms to the pentacene backbone leads to N-heteropentacenes, whose properties can be tuned by changing the number, position and valence state of N atoms in the pentacene backbone. With a rapid development in recent years, N-heteropentacenes and their derivatives have arisen as a new family of organic semiconductors with high performance in organic thin-film transistors (OTFTs). This article reviews the research efforts of developing N-heteropentacenes into organic semiconductors starting from 2003 with emphasis on the work of the author's group since 2009. The structure-property relationship and design rationale are highlighted based on an overview of reported organic semiconductors of N-heteropentacenes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recently, various metal nanostructures have been introduced into organic solar cells (OSCs) for performance enhancement. Here, we review the recent progress in OSCs incorporated with multiple metal nanostructures including various metal nanopatterns and metal nanomaterials. Multiple physical effects arise from these incorporated nanostructures, which require careful distinction. Changes induced by the metal nanostructures are examined in detail from the optical and electrical aspects. With the comprehensive understanding of the physical mechanisms for various metal nanostructures, further improvement in device performance and emerging applications can be expected for the new class of nanostructure-incorporated OSCs. This journal is © the Partner Organisations 2014.

Pan W.,University of Hong Kong
Renewable and Sustainable Energy Reviews | Year: 2014

Zero carbon building has been regarded as an important approach in reducing the carbon emissions associated with buildings. However, despite significant policy drivers, the uptake of this approach has been low. This paper examines the concepts and develops a theoretical model of the system boundaries of zero carbon buildings. Previous research is largely grounded in the net (nearly) zero carbon/energy parameter and focuses on buildings operations. However, there is increasing awareness of the need for lifecycle approaches to address carbon emissions and for boundaries to be defined to help elaborate the concept and guide research. The developed model covers eight types of boundaries, the policy timeframe, building lifecycle, geographic, climatic, stakeholder, sector, density and institutional boundaries. These boundaries are dynamic and interactive. It is concluded that zero carbon buildings should be regarded as complex socio-technical systems, but should not be exaggerated as surrogates for sustainable buildings. The findings are confirmed with case studies of five pioneering zero carbon buildings worldwide. The case studies demonstrate the great diversity and complexity of zero carbon building boundaries and assert that without the explicit specification of the boundaries, the comparison of cases in different contexts is like "comparing apples to pears." © 2014 Elsevier Ltd.

Miao Q.,Chinese University of Hong Kong | Miao Q.,University of Hong Kong
Synlett | Year: 2012

N-Heteropentacenes and their derivatives have been recently discovered as a new family of organic semiconductors exhibiting high performance in organic field effect transistors (OFETs). Introducing nitrogen atoms to the pentacene moiety leads to a large number of structurally related -backbones with tunable electronic structures, stability, solubility, and molecular packing. This gives considerable freedom when designing organic semiconductors and provides good opportunities for studying structure-property relationships. In this account, efforts on developing N-heteropentacenes and N-heteropentacenequinones as organic semiconductors are reviewed, with focus on the recent work of our own group. 1 Overview 2 Brief Introduction to Organic Semiconductors and Organic Field Effect Transistors 3 Dihydrodiazapentacenes and Diazapentacenes 4 A Dihydrotetraazapentacene and Its Methylated Derivatives 5 N- Heteropentacenequinones 6 Silylethynylated N-Heteropentacenes 7 Conclusion and Outlook. © Georg Thieme Verlag Stuttgart · New York.

Chu L.W.,University of Hong Kong
Hong Kong Medical Journal | Year: 2012

With ageing of populations, the worldwide population of persons with dementia will reach over 81 million by 2040, of which the most common cause is Alzheimer's disease. In recent years, there have been major advances in the understanding of its pathogenesis, methods to diagnose it, and treatment. Magnetic resonance brain imaging, cerebrospinal fluid biomarkers, and Pittsburgh compound B and fluorodeoxyglucose positron emission tomography of the brain can facilitate an accurate diagnosis of Alzheimer's disease in its early stage, and diagnose the mild cognitive impairment stage of Alzheimer's disease. At present, only symptomatic but not disease-modifying drug treatments are available. Donepezil, rivastigmine and galantamine are the currently approved cholinesterase inhibitors for the treatment of mild, moderate, and severe Alzheimer's disease. Overall, cholinesterase inhibitors show beneficial effects on cognition, activity of daily living, behaviour, and overall clinical rating. Memantine is another symptomatic treatment for moderate-to-severe Alzheimer's disease patients. It has a small beneficial effect on cognition, activity of daily living, behaviour, and overall clinical rating. Vitamin E has antioxidant properties, and may be used in some Alzheimer's disease patients without vascular risk factors. Concurrent non-pharmacological and psychosocial management of patients and their caregivers have a very important role. Disease-modifying therapies are still under development, whilst immunotherapy may be a viable option in the near future.

Li H.C.,University of Hong Kong
Psycho-oncology | Year: 2011

The treatment of cancer is a stressful and threatening experience, particularly for children. Knowing how children cope with cancer is a crucial step toward designing appropriate psychological interventions that help them ease the burden of cancer treatment. The purpose of this study was to examine the coping strategies used by Chinese children hospitalized with cancer, an area of research that is under-represented in the existing literature. Hong Kong Chinese children (9-16-year olds) admitted for cancer treatment to the pediatric oncology units of two different regional acute public hospitals were invited to participate. A short one-to-one structured interview was conducted with each participant. Content analysis was conducted to analyze the interview data. A convenience sample of 88 children was recruited and participated in the interviews during an 8-month period. The coping strategies used by Chinese children hospitalized with cancer did not differ according to gender and diagnosis, but only according to age, with younger children using less problem-focused and more emotion-focused coping strategies than older children. The overall results indicated that 30% of these Chinese patients used problem-focused coping strategies, while 70% used emotion-focused coping. Findings from this study indicated that children use different coping strategies at different developmental stages. The study also revealed that Chinese children used more emotion-focused than problem-focused coping strategies than their Western counterparts. The information derived from this study will help health-care professionals design and shape appropriate psychological interventions that can help reduce the burden of cancer treatment. Copyright © 2010 John Wiley & Sons, Ltd. Copyright © 2010 John Wiley & Sons, Ltd.

Yuen M.-F.,University of Hong Kong
Hepatology International | Year: 2015

Hepatitis B virus (HBV) reactivation with hepatic decompensation leading to acute on chronic liver failure is not uncommon. It is associated with high mortality of up to 30–70 %. Prognostic factors for mortality include high bilirubin level, more prolonged prothrombin time, low platelet count and presence of pre-existing cirrhosis. Several studies addressing the efficacy of different anti-viral therapies, namely lamivudine, entecavir and tenofovir, have been performed. Although the results were not highly consistent, it appeared that use of anti-viral agents was associated with decreasing chance of mortality, subsequent HBV reactivation, disease progression, and with excellent viral suppression. The beneficial effects were most prominently observed in patients with MELD score 20–30. However, even with anti-viral therapy, patients may still have irreversible liver decompensation requiring liver transplantation if other adverse parameters. including pre-existing cirrhosis, bilirubin >20 mg/dL (340 µmol/L), prothrombin time <40 %, platelet count <120 × 109/L. were present. Mortality rate in patients with MELD score >30 was >92 % even with prompt anti-viral treatment. Liver transplantation should be considered urgently. © 2014, Asian Pacific Association for the Study of the Liver.

Background: Rosiglitazone (Ros) has been shown to attenuate CXCL8 and ICAM-1 overexpression in renal tubular cells exposed to glycated albumin. The present study explores whether this can be translated into renoprotection in vivo. Uninephrectomized (Unx) type 2 diabetic db/db mice were chosen as a model of accelerated diabetic nephropathy. Methods: Uninephrectomy was performed in 10-week-old db/db mice. They were then treated with vehicle, metformin or Ros for 8 weeks. Results: Unx-db/db mice treated with Ros had lower serum creatinine and albuminuria, less severe glomerulosclerosis, tubulointerstitial injury, fewer infiltrating macrophages, and less proliferating nuclear antigen-positive tubular cells compared with mice treated with metformin that had a similar level of glycemic control and insulin resistance. In addition, Ros but not metformin attenuated renal cortical expression of CCL2, MIP-2, and ICAM-1 and inhibited p-STAT1 signal activation. Ros also increased glomerular nephrin expression. Conclusions: Our results delineated the biochemical and histologic characteristics of Unx-db/db mice and demonstrated the in vivo glucose-independent anti-inflammatory mechanisms of Ros in nephropathy of accelerated murine type 2 diabetes. Copyright © 2010 S. Karger AG, Basel.

Leung D.Y.C.,University of Hong Kong | Caramanna G.,Heriot - Watt University | Maroto-Valer M.M.,Heriot - Watt University
Renewable and Sustainable Energy Reviews | Year: 2014

Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process. © 2014 Published by Elsevier Ltd.

Yang X.,Chinese University of Hong Kong | Liu D.,Chinese University of Hong Kong | Miao Q.,Chinese University of Hong Kong | Miao Q.,University of Hong Kong
Angewandte Chemie - International Edition | Year: 2014

This study presents a new class of conjugated polycyclic molecules that contain seven-membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have a nearly flat C 6-C7-C6-C7-C6 polycyclic framework with a p-quinodimethane core. With field-effect mobilities of up to 0.76cm2V-1s-1 as measured from solution-processed thin-film transistors, these molecules are alternatives to the well-studied pentacene analogues for applications in organic electronic devices. All sixes and sevens: A new class of conjugated polycyclic molecules have a nearly flat C6-C7-C6-C 7-C6 polycyclic framework with a p-quinodimethane core. With a field-effect mobility of up to 0.76cm2V-1s -1 as measured from solution-processed thin-film transistors, these molecules are alternatives to the pentacene analogues for application in organic electronic devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lau C.-P.,University of Hong Kong | Zhang S.,Peking Union Medical College
Europace | Year: 2013

Remote monitoring of pacemakers and implantable cardioverter defibrillators (ICDs) has emerged as a tool to replace regular follow-up of such devices, and to detect hardware failure, arrhythmias, and heart failure decompensation. The Asia-Pacific region is a geographically diverse area, with widely different cardiac device implant rates and expertise. However, common to all countries, distance and logistic for patients to reach an expert monitoring centre for routine follow up are significant, and in some countries, this will likely be replaced by remote monitoring. Unscheduled visits such as for the treatment of atrial fibrillation and ICD shocks will be expedited.There has been an increase in both pacemaker and ICD implant rates in Asia-Pacific, due to an ageing population and improvement in economic condition. Among the countries, Australia and Japan are the major users of remote monitoring. According to the statistics of the suppliers, in Australia, up to 15% of pacemakers, 40% ICD, and 30% cardiac resynchronization therapy (CRT)/cardiac resynchronization therapy defibrillator (CTRD) are remotely monitored. The corresponding numbers for Japan are 5, 50, and 50% respectively. The monitoring personnel include nurses, technicians, and doctors, either from local centre or from device companies. Cost, lack of reimbursement, and logistic support are major issues in widespread application of remote monitoring technology.In conclusion, remote monitoring is increasing in Asia-Pacific region despite the increase in cost. Implantable cardioverter defibrillators and CRT/CRTDs are more likely than pacemakers to be enabled with remote monitoring Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2013.

Cheng K.K.-Y.,University of Hong Kong
British Journal of Criminology | Year: 2013

Guilty pleas are the primary mode of case dispositions in the common law world, and its propensity is seen to undermine due process principles. Hong Kong for many remains a steadfast protector of due process despite its handover back to China. The written law in Hong Kong, while emphasizing the importance of ensuring defendants make their plea decisions free from any improper pressure, neglects the intrinsic pressures brought upon by having to go through the criminal justice process. Results from courtroom observations in two Hong Kong magistrates' courts indicate that defendants who made an admission, represented themselves and were denied bail were more likely to plead guilty. Overall, defendants plead guilty to terminate as quickly as possible the 'punishment' of being caught up in the criminal justice system. © 2012 The Author.

Fraser A.,University of Hong Kong
Theoretical Criminology | Year: 2013

In the current era of globalization, a paradox has developed in the field of criminology. In the context of the increasingly global nature of crime, there has been a firm recognition among criminologists of the need for comparative, transnational research; particularly that which moves beyond knowledge created in the global North. However, production of this knowledge remains clustered in a relatively narrow range of geographical sites-and understandings of crime and criminology in the South too often defined through the lens of the North. As processes of globalization confound and disrupt the traditional dualisms of East/West and North/South, there is a pressing need for an expansion of criminology's world-map. This article explores the conceptual possibilities of one particular methodology-ethnography-as a means of explicating the deep-seated tensions, fragmented realities and hybridized identities that emerge from the margins of globalization. Drawing on cogent debates from the fields of sociology and anthropology, I argue that ethnographically informed 'theory from the South' can at once enrich the criminological imagination and provoke a more cosmopolitan global imaginary. © The Author(s) 2013.

Chan K.-H.,HKU Shenzhen Institute of Research and Innovation | Guan X.,University of Hong Kong | Lo V.K.-Y.,HKU Shenzhen Institute of Research and Innovation | Che C.-M.,HKU Shenzhen Institute of Research and Innovation
Angewandte Chemie - International Edition | Year: 2014

Bis(NHC)ruthenium(II)-porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans Mï£CRR′/Mï£NR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene C-H, N-H, S-H, and O-H insertion, alkene aziridination, and nitrene C-H insertion with turnover frequencies up to 1950 min-1. The use of chiral [Ru(D4-Por)(BIMe)2] (1 g) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % ee. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the trans axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal-carbene reaction intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wardman J.K.,University of Hong Kong
Journal of Risk Research | Year: 2014

Kasperson's reflections on the 'state of the art' in risk communication thinking and practice set out an ambitious programmatic vision of how future progress in effective risk communication might be achieved. In this critical but supportive response, I first outline two perspectives on how progress in risk communication might be evaluated. This is followed by some discussion relating these issues to the sociocultural nature of risk communication thinking and practice, and the normative basis of underlying assumptions and ideas of effectiveness. It is suggested that inasmuch as the practical application of effective risk communication requires knowledge of human thinking and behaviour, then further considerations of some sociocultural regularities, contingencies and varieties in risk communication thinking and behaviour within particular contexts should also have practical applications. © 2014 Taylor & Francis.

Han G.,University of Hong Kong | Marcus B.H.,University of British Columbia
IEEE Transactions on Information Theory | Year: 2012

We consider a memoryless channel with an input Markov process supported on a mixing finite-type constraint. We continue the development of asymptotics for the entropy rate of the output hidden Markov chain and deduce that, at high signal-to-noise ratio, the mutual information rate of such a channel is concave with respect to "almost" all input Markov chains of a given order. © 2012 IEEE.

Li Y.,University of Hong Kong
Science and Engineering Ethics | Year: 2013

Text-based plagiarism, or copying language from sources, has recently become an issue of growing concern in scientific publishing. Use of CrossCheck (a computational text-matching tool) by journals has sometimes exposed an unexpected amount of textual similarity between submissions and databases of scholarly literature. In this paper I provide an overview of the relevant literature, to examine how journal gatekeepers perceive textual appropriation, and how automated plagiarism-screening tools have been developed to detect text matching, with the technique now available for self-check of manuscripts before submission; I also discuss issues around English as an additional language (EAL) authors and in particular EAL novices being the typical offenders of textual borrowing. The final section of the paper proposes a few educational directions to take in tackling text-based plagiarism, highlighting the roles of the publishing industry, senior authors and English for academic purposes professionals. © 2012 The Author(s).

Khambay B.,University of Hong Kong | Ullah R.,Birmingham Dental Hospital
International Journal of Oral and Maxillofacial Surgery | Year: 2015

Since the introduction of three-dimensional (3D) orthognathic planning software, studies have reported on their predictive ability. The aim of this study was to highlight the limitations of the current methods of analysis. The predicted 3D soft tissue image was compared to the postoperative soft tissue. For the full face, the maximum and 95th and 90th percentiles, the percentage of 3D mesh points ≤2 mm, and the root mean square (RMS) error, were calculated. For specific anatomical regions, the percentage of 3D mesh points ≤2 mm and the distance between the two meshes at 10 landmarks were determined. For the 95th and 90th percentiles, the maximum difference ranged from 7.7 mm to 2.2 mm and from 3.7 mm to 1.5 mm, respectively. The absolute mean distance ranged from 0.98 mm to 0.56 mm and from 0.91 mm to 0.50 mm, respectively. The percentage of mesh with ≤2 mm for the full face was 94.4-85.2% and 100-31.3% for anatomical regions. The RMS error ranged from 2.49 mm to 0.94 mm. The majority of mean linear distances between the surfaces were ≤0.8 mm, but increased for the mean absolute distance. At present the use of specific anatomical regions is more clinically meaningful than the full face. It is crucial to understand these and adopt a protocol for conducting such studies. © 2014 International Association of Oral and Maxillofacial Surgeons.

Chan S.C.,University of Hong Kong
Transplantation | Year: 2014

Liver transplantation (LT) is the most effective treatment for small and unresectable hepatocellular carcinomas (HCCs). With scarcity of deceased donor livers, living donor LT (LDLT) is the alternative to deceased donor LT (DDLT). Animal studies have suggested that regeneration of the partial liver graft encourages HCC recurrence. Increased recurrence was observed in a few studies. Thus, there is the belief that the use of small-for-size graft carries the potential risk of disease recurrence. Nevertheless, those studies were retrospective, with sample sizes not large enough for conclusions.Living donor LT can be performed when a suitable donor is available. The fast tracking of patients for transplantation without a period of observation is an issue. Meta-analyses, however, showed no significant increase in HCC recurrence after LDLT. Patients listed for DDLT and without suitable living donors have to endure a long wait, during which the aggressiveness of their HCC is observed. Such observation almost guarantees slow disease progression when they get transplanted. Nevertheless, a long wait has the disadvantage of transplanting patients with more advanced tumors, although still within standard criteria. Judicious use of deceased donor grafts is the responsibility of the transplant community.Living donor LT for HCC should only be performed after careful assessment of the recipient and tumor status. Although tumor size and number are references widely adopted in tumor staging, biological staging of tumors using positron emission tomography could provide additional information of tumor behavior. A high level of serum α-fetoprotein also warns against LT because it is predictive of a high HCC recurrence rate.

Cheung B.M.Y.,University of Hong Kong
Drug Safety | Year: 2011

Obesity is a major health problem worldwide. It is associated with cardiovascular diseases, diabetes mellitus and decreased longevity. In managing obesity, diet and exercise are essential; pharmacological therapy may be added for obese patients or overweight patients with cardiovascular risk factors. Sibutramine is a serotonergic and adrenergic drug that reduces food intake and increases thermogenesis. It reduces bodyweight by about 4.2kg after 12 months, and improves blood glucose and lipids; however, it can increase heart rate and blood pressure. In the SCOUT (Sibutramine Cardiovascular OUTcomes) study, sibutramine increased serious cardiovascular events, such as stroke or myocardial infarction, compared with placebo, and was consequently withdrawn from the market. The lesson learnt from this is the importance of patient selection, limiting the duration of treatment and stopping treatment in non-responders. Currently, phentermine and amfepramone (diethylpropion) are approved for short-term treatment of obesity (up to 3 months) and orlistat is approved for longer-term treatment; however, the gastrointestinal adverse effects of orlistat may be intolerable for some patients. There is now a clear need to find anti-obesity drugs that are effective and safe in the long term. © 2011 Adis Data Information BV. All rights reserved.

Vanhoutte P.M.,University of Hong Kong
Circulation Journal | Year: 2016

This essay summarizes 30 years of work attempting to understand why regenerated endothelium becomes dysfunctional. It focuses on the activation of endothelial nitric oxide synthase (eNOS) and the production of NO in response to platelet products and thrombin, which represents a first-line protection against vasospasm and atherosclerosis. Serotonin and adenosine diphosphate released by aggregating platelets are coupled to the activation of eNOS by different G-proteins. The endothelium-dependent relaxation that they cause is modulated non-selectively by the lipid content in the diet. When the endothelium regenerates after mechanical disruption, the newly formed endothelial cells selectively lose their Gi-mediated coupling and become less responsive to serotonin and thrombin. Accelerated senescence and the emergence of adipocyte-fatty acid binding protein leading to increased oxidative stress play a key role in the genesis of the dysfunction of regenerated endothelium. The consequent local NO deficiency not only favors the occurrence of vasospasm but sets the stage for the occurrence of atherosclerosis. © 2016, Japanese Circulation Society. All rights reserved.

Pan W.,University of Hong Kong | Garmston H.,University of Plymouth
Energy | Year: 2012

Despite increasingly stringent building energy regulations worldwide, non-compliance exists in practice. This paper examines the profile of compliance with building energy regulations for new-build dwellings. In total 404 new-build dwellings completed in the UK from 2006 to 2009 were investigated. Only a third of these dwellings were evidenced as being compliant with Building Regulations Part L (England and Wales). Such low compliance casts a serious concern over the achievability of the UK Government's target for all new-build homes to be 'zero carbon' from 2016. Clearly evidenced was a lack of knowledge of Part L and its compliance requirements among the supply and building control sides of new-build dwellings. The results also indicate that the compliance profile was influenced by factors including Standard Assessment Procedure (UK Government's methodology for energy efficiency) calculation submissions, learning and experience of builders and building controls with Part L, use of Part L1A checklist, the introduction of energy performance certificate (EPC), build method, dwelling type, and project size. Better compliance was associated with flats over houses and timber frame over masonry. The use of EPC and Part L1A checklist should be encouraged. Key to addressing the lack of compliance with building energy regulations is training. © 2012 Elsevier Ltd.

Chiu H.Y.,University of Hong Kong
Anatomical sciences education | Year: 2012

Body donation is important for medical education and academic research. However, it is relatively rare in Hong Kong when compared with many Western countries. Comprehensive research has been performed on the motivation for body donation in Western countries; however, there is still insufficient research on body donation in Hong Kong to provide information on how to increase the body-donation rate. To understand the factors involved in the decision to donate one's body, the authors interviewed a registered donor and the daughter of another donor in Hong Kong. The authors interpreted the information collected in light of the available published reports, which mostly focus on body donation in Western countries. Despite the consistency of some demographic factors and motivations between the participants in our study and those investigated in the published reports from Western countries, there are differences in education level and socioeconomic status between the donors in our study and those from Western studies. The authors also suggest that Confucianism and Buddhism in Chinese culture may motivate potential body donors in Hong Kong. Other important factors that influence the body-donation decision may include family members' body donation, registration as organ donors, and good doctor-patient relationships. Although case report studies have their limitations, this study allows us to explore the complexity of events and establish the interconnectivity of factors involved in body donation, which could not be achieved in previous survey-based studies. Copyright © 2012 American Association of Anatomists.

Wang A.Y.M.,University of Hong Kong
Seminars in Nephrology | Year: 2014

Hypertension is a highly prevalent problem worldwide, affecting at least one third of the adult general population. Although the exact prevalence is uncertain, it is estimated that at least 15% to 20% of individuals with hypertension have resistant hypertension. Resistant hypertension has been shown to predict more adverse cardiovascular and renal outcomes. In 2003, the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure recognized obstructive sleep apnea (OSA) as an important cause of secondary hypertension. A large body of epidemiologic evidence has linked OSA to resistant hypertension, nondipping nocturnal blood pressure, as well as target organ damage, including left ventricular hypertrophy, arterial stiffness, and microalbuminuria. The importance of OSA as a risk factor for the development of hypertension independent of other confounding factors also was observed in a prospective longitudinal study. More importantly, OSA predicts an increased risk of adverse cardiovascular outcomes, mortality, and sudden cardiac death. This article discusses the associations between OSA and resistant hypertension and reviews the latest understanding on the pathophysiologic mechanisms of hypertension in OSA. Nocturnal continuous positive airway pressure therapy is regarded as the standard treatment for OSA. Prospective randomized controlled trials and meta-analyses of prospective randomized controlled trials within the past 10 years that have examined the effects of continuous positive airway pressure therapy on blood pressure control in patients with OSA with or without hypertension are reviewed and summarized. The majority of the trials suggest a modest but significant benefit on blood pressure control with continuous positive airway pressure therapy. Whether continuous positive airway pressure therapy may improve hard outcomes of patients with OSA and resistant hypertension warrants further investigation. © 2014 Elsevier Inc.

Pilnick A.,University of Nottingham | Zayts O.,University of Hong Kong
Sociology of Health and Illness | Year: 2012

There now exists a considerable body of sociological work examining antenatal screening for fetal abnormalities. A common theme emerging from this literature is that pregnant women report not feeling able to exercise choice freely, experiencing constraints both from medical professionals and their perceived expectations of the sociocultures in which they live. This study adds to existing literature in three ways. Firstly, in contrast to the existing body of interview-based research, the study uses video recordings of actual consultations, in order to capture the interactional processes through which choice and constraints are established, negotiated and contested. Secondly, it explores the next stage in the process of antenatal screening, by focusing on women who are offered invasive diagnostic testing as a result of 'high risk' screening results, and who have been the subject of little research. Thirdly, the study site in Hong Kong provides a particularly interesting location, given limited research on antenatal screening in that part of the world, and Hong Kong's cosmopolitan environment that is reflected in the diversity of client population undergoing antenatal screening. Using conversation analysis we examine how aspects of the clients' diverse socioeconomic backgrounds and circumstances are interactionally managed in this setting, and how this might impact on decision-making. © 2011 The Authors. Sociology of Health & Illness © 2011 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.

Zhao W.,Jiangsu University | Cheng M.,Nanjing Southeast University | Chau K.T.,University of Hong Kong | Cao R.,Nanjing Southeast University | Ji J.,Jiangsu University
IEEE Transactions on Industrial Electronics | Year: 2013

Redundant flux-switching permanent-magnet (R-FSPM) motors are a new class of brushless machines having magnets in the stator, offering high power density, simple and robust rotor structure, and good thermal dissipation conditions. This paper proposes a new control strategy for fault-tolerant operation of the R-FSPM motor drive considering the capability limitation of the power converter. The key is to operate the R-FSPM motor in the remedial mode by injecting harmonic currents, the so-called remedial injected-harmonic-current (RIHC) operation mode. Moreover, the motor losses at the existing and the proposed remedial operations are compared for evaluation. Both cosimulation and experimental results are presented, confirming that the proposed RIHC operation can offer good steady-state and dynamic performances while reducing the motor losses and the capability requirements of the power converter during fault. © 2012 IEEE.

Lo S.H.,University of Hong Kong
Finite Elements in Analysis and Design | Year: 2013

In the light of the simplicity and the linearity of regular grid insertion, a multi-grid insertion scheme is proposed for the Delaunay triangulation of uniform and non-uniform point distributions by recursive application of the regular grid insertion to an arbitrary subset of the original point set. The fundamentals and difficulties of Delaunay triangulation of highly non-uniformly distributed points by the insertion method are discussed. Current strategies and methods of point insertions for non-uniformly distributed points are reviewed. An enhanced kd-tree insertion scheme with specified number of points in a cell and its natural sequence of insertion are presented. The regular grid insertion, the enhanced kd-tree insertion and the multi-grid insertion have been thoroughly tested with benchmark non-uniform distributions of 1-100 million points. It is found that the kd-tree insertion is very sensitive to the triangulation of non-uniform point distributions with a large amount of conflicting elongated triangles. Multi-grid insertion is the most stable and efficient for all the uniform and non-uniform point distributions tested. © 2012 Elsevier B.V. All rights reserved.

As a key actor behind the emerging global biofuels market, the European Union has introduced environmental regulations governing such products. This article analyses the biofuels 'meta-standard' certification scheme which creates a transnational governance regime involving a regional bloc including States, non-governmental organisations and businesses in a hybrid regulatory model combining elements of private certification and public authority. A comparison of the role of Designated Operational Entities in the Kyoto Protocol's Clean Development Mechanism (CDM) and the certification schemes in the EU sustainability regulatory regime demonstrates that the problems that threaten the environmental integrity of the CDM are less likely to emerge in the EU biofuels context. copy; The Author 2011. Published by Oxford University Press. All rights reserved.

Zhong W.X.,University of Hong Kong | Hui S.Y.R.,Imperial College London
IEEE Transactions on Power Electronics | Year: 2015

A method for automatic "maximum energy efficiency tracking" operation for wireless power transfer (WPT) systems is presented in this paper. Using the switched-mode converter in the receiver module to emulate the optimal load value, the proposed method follows the maximum energy efficiency operating points of a WPT system by searching for the minimum input power operating point for a given output power. Because the searching process is carried out on the transmitter side, the proposal does not require any wireless communication feedback from the receiver side. The control scheme has been successfully demonstrated in a two-coil system under both weak and strong magnetic coupling conditions. Experimental results are included to confirm its feasibility. © 2014 IEEE.

Yip C.C.,University of Hong Kong
Emerging health threats journal | Year: 2013

Human enterovirus 71 (EV71) epidemics have affected various countries in the past 40 years. EV71 commonly causes hand, foot and mouth disease (HFMD) in children, but can result in neurological and cardiorespiratory complications in severe cases. Genotypic changes of EV71 have been observed in different places over time, with the emergence of novel genotypes or subgenotypes giving rise to serious outbreaks. Since the late 1990s, intra- and inter-typic recombination events in EV71 have been increasingly reported in the Asia-Pacific region. In particular, 'double-recombinant' EV71 strains belonging to a novel genotype D have been predominant in mainland China and Hong Kong over the last decade, though co-circulating with a minority of other EV71 subgenotypes and coxsackie A viruses. Continuous surveillance and genome studies are important to detect potential novel mutants or recombinants in the near future. Rapid and sensitive molecular detection of EV71 is of paramount importance in anticipating and combating EV71 outbreaks.

Zhao J.-H.,Wuhan University | Zhou M.-F.,University of Hong Kong
Precambrian Research | Year: 2013

The southeastern Yangtze Block, South China, contains voluminous late Neoproterozoic felsic plutonic rocks and minor mafic-ultramafic volcanic rocks. Some ca. 830Ma lavas hosted in the Neoproterozoic strata have pillow structures and micro-spinifex textures and thus previously were considered as komatiitic basalts derived from a mantle plume. These rocks have high MgO (10.1-16.3wt%), variable CaO (6.57-11.2wt%), restricted Al2O3 (11.2-13.4wt%), and low TiO2 (0.50-0.61wt%), P2O5 (0.03-0.04wt%) and incompatible trace elements. They also have negative εNd (-5.4 to -2.9), and high 207Pb/204Pb (15.71-15.76) and initial 187Os/188Os ratios (0.1100-0.1931), indicating crustal contamination. The most primitive samples show arc-like trace elemental features which are characterized by enrichment of LREE and LILE relative to HFSE in the primitive-mantle-normalized trace-element diagrams, suggesting derivation from enriched mantle sources. PRIMELT2 modeling shows that their primary magmas were produced by about 30% partial melting of a fertile peridotite source having a mantle potential temperature of 1440-1500°C. Such a potential temperature is in agreement with the estimates for ambient mantle during the Neoproterozoic. These evidence suggest that the high-Mg basalts are similar to boninites and probably be part of an ophiolite assemblage. They were generated by melting of a hot ambient mantle source in relation to slab subduction during the amalgamation of the Yangtze and Cathaysia Blocks. © 2013 Elsevier B.V.

Lo S.H.,University of Hong Kong
Computers and Structures | Year: 2013

Abstract The advancing front approach is known to be robust, versatile over domains of different dimensions with diverse geometrical and topological characteristics, and is able to generate elements of various types such as triangles, quadrilaterals, tetrahedra and hexahedra close to the well-shaped ideal geometry in compliance with the specified node spacing specification. However, the main inconvenience with the advancing front approach is its efficiency in handling a large number of elements. Whenever a new element is formed, we have to assure that segments created do not penetrate into the generation front, and the search over the entire generation front to ensure no intersection is a rather time-consuming process. In this paper, a dynamic grid approach for the advancing front method is presented to generate adaptive triangular meshes of variable element size over arbitrary planar domains. A simple domain partition scheme with little demand on additional memory is proposed, which could drastically reduce the search time over the generation front. Variable number of objects can be stored in an individual cell so that a coarse grid could be employed for relatively complex meshes. A dynamic marking and unmarking of cells intersected by a line segment is devised so as to cope with the changing boundary conditions during mesh generation. From the tests of two series of adaptive meshes with size up to one million elements on a PC, the use of partition grid could substantially reduce the CPU time by more than five times compared to mesh generation by the same procedure without a background grid. © 2013 Elsevier Ltd. All rights reserved.

Zhao J.-H.,Wuhan University | Zhou M.-F.,University of Hong Kong | Zheng J.-P.,Wuhan University
Precambrian Research | Year: 2013

The Huangling igneous complex in the central Yangtze Block, South China, consists of the 850-Ma tonalite and trondhjemite which were intruded by the 826±13Ma high-K granite. The granites are composed of plagioclase (30-60%), alkali feldspar (10-30%), quartz (20-30%), biotite (<10%) and hornblende (<5%). Both hornblende and biotite have high Ti and low Al contents, indicating high liquidus temperature. The granites have high SiO2 (63.1-73.3wt.%), K2O (2.58-4.79wt.%) and Na2O (3.90-5.89wt.%) and low MgO (0.49-1.78wt.%) and are magnesian alkali-calcic in composition. Their chondrite - normalized REE patterns are characterized by enrichment of LREE (La/YbN=14.5-32.8) and mostly negative Eu anomalies (Eu/Eu*=0.5-1.1). They have moderately high Sr (202-698ppm) and low Y (6.13-18.7ppm) with Sr/Y ratios of 14-64. These large elemental variations probably resulted from fractional crystallization. They also have negative whole rock εNd (-9.75 to -11.73) and zircon εHf values (-7.1 to -15.8) which are similar to those of the Neoproterozoic mafic rocks in the same region, suggesting that the granites may have been produced by melting of newly-emplaced mafic rocks. Tonalites and trondhjemites of the Huangling complex previously were considered as products by differentiation of water-rich basaltic magmas and melting of the thickened Archean continental crust in an arc setting, respectively. Therefore, the crustal growth and reworking of the Yangtze Block were probably wholly controlled by the subduction system which resulted in formation of the stable continent during the Neoproterozoic. © 2013.

Shellnutt J.G.,Academia Sinica, Taiwan | Jahn B.-M.,Academia Sinica, Taiwan | Zhou M.-F.,University of Hong Kong
Lithos | Year: 2011

In the Panxi region of the Late Permian (~260Ma) Emeishan large igneous province (ELIP) there is a bimodal assemblage of mafic and felsic plutonic rocks. Most Emeishan granitic rocks were derived by differentiation of basaltic magmas (i.e. mantle-derived) or by mixing between crustal melts and primary basaltic magmas (i.e. hybrid). The Yingpanliangzi granitic pluton within the city of Panzhihua intrudes Sinian (~600Ma) marbles and is unlike the mantle-derived or hybrid granitic rocks. The SHRIMP zircon U-Pb ages of the Yingpanliangzi pluton range from 259±8Ma to 882±22Ma. Younger ages are found on the zircon rims whereas older ages are found within the cores. Field relationships and petrography indicate that the Yingpanliangzi pluton must be <600Ma, therefore the older zircons are interpreted to represent the protolith age whereas the younger analyses represent zircon re-crystallization during emplacement. The Yingpanliangzi granites are metaluminous and have negative Ta-NbPM anomalies, low εNd(260 Ma) values (-3.9 to -4.4), and high ISr (0.71074 to 0.71507) consistent with a crustal origin. The recognition of a crustally-derived pluton along with mantle-derived and mantle-crust hybrid plutons within the Panxi region of the ELIP is evidence for a complete spectrum of sources. As a consequence, the types of Panxi granitoids can be distinguished according to their ASI, Eu/Eu*, εNd(T), εHf(T), TZr(°C) and Nb-TaPM values. The diverse granitic magmatism during the evolution of the ELIP from ~260Ma to ~252Ma demonstrates the complexity of crustal growth associated with LIPs. © 2010 Elsevier B.V.

Minazzoli O.,Jet Propulsion Laboratory | Harko T.,University of Hong Kong
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In this paper we give a simple proof that when the particle number is conserved, the Lagrangian of a barotropic perfect fluid is L m=- ρ[c2+P(ρ)/ρ2dρ], where ρ is the rest mass density and P(ρ) is the pressure. To prove this result, neither additional fields nor Lagrange multipliers are needed. Besides, the result is applicable to a wide range of theories of gravitation. The only assumptions used in the derivation are: 1) the matter part of the Lagrangian does not depend on the derivatives of the metric, and 2) the particle number of the fluid is conserved ( σ(ρuσ)=0). © 2012 American Physical Society.

Chan J.K.Y.,University of Hong Kong | Wong M.H.,Hong Kong Baptist University
Science of the Total Environment | Year: 2013

This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16. pg. WHO-TEQ/kg. bw/day, exceeding the tolerable daily intakes recommended by the WHO (1-4. pg. WHO-TEQ/kg. bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60-99% of the total intakes. Inhalation is the second major exposure route, accounted for 12-30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed. © 2012 Elsevier B.V.

Lung M.A.,University of Hong Kong
American Journal of Rhinology and Allergy | Year: 2011

Background: Acetylcholine (ACh) has been shown to induce nasal congestion via vasorelaxation of intranasal posterior collecting veins (PCV) coupled with vasocontraction of extranasal outflow veins (dorsal nasal vein [DNV] and sphenopalatine vein [SPV]). The aim of this study was to characterize the muscarinic receptor subtype(s) involved in ACh-induced relaxation and contraction in canine nasal veins. Methods: PCV, DNV, and SPV were isolated from the canine nose. In vitro isometric tension of segments from these veins was monitored to reflect vascular reactivity. ACh concentration-response curve was studied in the presence of muscarinic receptor subtype inhibitors. Immunohistochemical localization of M1-M5 receptor subtypes in the veins was performed. Results: ACh-induced relaxation in PVC was inhibited by pertussis toxin (PTX; inhibitor of G-protein that couples M2/M4 receptors), methoctramine (selective M2 muscarinic receptor inhibitor), muscarinic toxin 7 (MT-7; selective M1 muscarinic receptor inhibitor), and 4-diphenylacetoxy-methylpiperidine methiodide (4-DAMP; selective M3 muscarinic receptor inhibitor). ACh-induced contraction in SPV and DNV was potentiated by PTX and methoctramine but was inhibited by MT-7 and 4-DAMP. Immunohistochemistry confirmed the presence of five muscarinic receptor subtypes in the endothelium of nasal veins, with staining of M3 > M1 > M5 > M2 > M4 in PVC but M2 > M4 > M3 > M1 > M5 in outflow veins. M1 and M3 receptor subtypes were localized in the smooth muscles of both types of veins. Conclusion: The results show that ACh relaxes intranasal veins and contracts extranasal veins primarily via M 1 and M3 muscarinic receptor subtypes, implying the therapeutic value of M1/M3-specific or highly selective anticholinergics on nasal congestion. Copyright © 2011, OceanSide Publications, Inc.

Chesi G.,University of Hong Kong
IEEE Transactions on Automatic Control | Year: 2013

This technical note addresses robust stability of uncertain systems with rational dependence on unknown time-varying parameters constrained in a polytope. First, the technical note proves that a sufficient linear matrix inequality (LMI) condition that we previously proposed, based on homogeneous polynomial Lyapunov functions (HPLFs) and on the introduction of an extended version of Polya's theorem, is also necessary. Second, the technical note proposes a new sufficient and necessary LMI condition by exploiting properties of the simplex and sum-of-squares (SOS) parameter-dependent polynomials. Lastly, the technical note investigates relationships among these conditions and conditions based on the linear fractional representation (LFR). It is worth remarking that sufficient and necessary LMI conditions for this problem have not been proposed yet in the literature. © 1963-2012 IEEE.

Ahmed S.K.,University of Hong Kong
Hand surgery : an international journal devoted to hand and upper limb surgery and related research : journal of the Asia-Pacific Federation of Societies for Surgery of the Hand | Year: 2011

The distal radioulnar joint (DRUJ) is commonly affected in rheumatoid arthritis and is associated with significant functional morbidity. The aim of our study is to review our results with matched hemi-resection interposition arthroplasty in patients with DRUJ arthritis. This was a retrospective study of 39 patients with 51 wrists that were treated at Queen Mary Hospital in Hong Kong from 1989 to 2007. All patients underwent matched hemi-resection interposition arthroplasty and dorsal wrist synovectomy. Long arm hinged elbow brace was used for three weeks followed by intensive rehabilitation up to twelve weeks. The indicators of outcome included range of motion assessment, pain, wrist stiffness, grip of strength and need for revision assessed during follow-up. Statistical analysis was performed with student t-test. The average age of patients was 50.5 years (25 to 77 years) and there was a 35:4 female to male ratio. The average follow up was 4.5 years ranging from 1 to 18 years. Associated extensor tendon ruptures were found in 31.4% patients. The average increase in supination was from 73 degrees preoperatively to 81 degrees at long term follow up (p = 0.10 at 1 year and 0.13 at long term follow-up). The average increase in pronation was from 68 degrees preoperatively to 74 degrees on long term follow up (p = 0.57 at 1 year and 0.02 at long term follow-up). There was evidence of painless, relatively stiff but functional wrist in 37.25% of patients. There was an increase in grip strength from an average of 6.1 kilogram force preoperatively to an average of 11.5 kilogram force at follow-up (p = 0.004 at 1 year and 0.15 at long term follow-up). Complete relief of ulnar sided pain was seen in 43 wrists (84%), partial relief was seen in 7 wrists (13.7%) and no relief was found in one wrist (1.9%). DRUJ arthroplasty is a rewarding procedure and most of the patients obtain pain free movement.

To characterise the complete case series of influenza A/H7N9 infections as of 27 May 2013, detected by China's national sentinel surveillance system for influenza-like illness. Case series. Outpatient clinics and emergency departments of 554 sentinel hospitals across 31 provinces in mainland China. Infected individuals were identified through cross-referencing people who had laboratory confirmed A/H7N9 infection with people detected by the sentinel surveillance system for influenza-like illness, where patients meeting the World Health Organization's definition of influenza-like illness undergo weekly surveillance, and 10-15 nasopharyngeal swabs are collected each week from a subset of patients with influenza-like illness in each hospital for virological testing. We extracted relevant epidemiological data from public health investigations by the Centers for Disease Control and Prevention at the local, provincial, and national level; and clinical and laboratory data from chart review. Epidemiological, clinical, and laboratory profiles of the case series. Of 130 people with laboratory confirmed A/H7N9 infection as of 27 May 2013, five (4%) were detected through the sentinel surveillance system for influenza-like illness. Mean age was 13 years (range 2-26), and none had any underlying medical conditions. Exposure history, geographical location, and timing of symptom onset of these five patients were otherwise similar to the general cohort of laboratory confirmed cases so far. Only two of the five patients needed hospitalisation, and all five had mild or moderate disease with an uneventful course of recovery. Our findings support the existence of a "clinical iceberg" phenomenon in influenza A/H7N9 infections, and reinforce the need for vigilance to the diverse presentation that can be associated with A/H7N9 infection. At the public health level, indirect evidence suggests a substantial proportion of mild disease in A/H7N9 infections.

Lai M.H.,University of Hong Kong | Ho J.C.M.,University of Queensland
Journal of Constructional Steel Research | Year: 2015

Nowadays reinforced concrete (RC) columns are commonly adopted in tall building structures. One of its associated problems is that the transverse steel cannot confine the concrete cover and has limited effect on the ductility improvement, particularly of those made of high-strength concrete (HSC). Therefore, there is usually a maximum limit of concrete strength that can be used. To further push up this limit, concrete-filled-steel-tube (CFST) columns are advocated for its better performance contributed by the composite action. However, this composite action cannot be fully developed because of different dilation properties between steel tube and concrete, and very often de-bonding between the constitutive materials will occur initially. To overcome this problem, external confinement in the form of spirals is proposed to improve the interface bonding. In this paper, a total of 38 specimens were fabricated and tested under uni-axial compression. From the results, it can be concluded that the proposed spirals can improve the strength, initial stiffness, ductility and the interface bonding by restraining the lateral expansion of steel tube and core concrete. Lastly, an analytical model evaluating the ultimate strength of spiral-confined CFST columns is proposed and verified. © 2014 Elsevier Ltd. All rights reserved.

Cheuk D.K.,University of Hong Kong
Cochrane database of systematic reviews (Online) | Year: 2012

Although conventional non-pharmacological and pharmacological treatments for insomnia are effective in many people, alternative therapies such as acupuncture are widely practised. However, it remains unclear whether current evidence is rigorous enough to support acupuncture for the treatment of insomnia. To determine the efficacy and safety of acupuncture for insomnia. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, Dissertation Abstracts International, CINAHL, AMED, the Traditional Chinese Medical Literature Analysis and Retrieval System (TCMLARS), the World Health Organization (WHO) Trials Portal (ICTRP) and relevant specialised registers of the Cochrane Collaboration in October 2011. We screened reference lists of all eligible reports and contacted trial authors and experts in the field. Randomised controlled trials evaluating any form of acupuncture for insomnia. They compared acupuncture with/without additional treatment against placebo or sham or no treatment or same additional treatment. We excluded trials that compared different acupuncture methods or acupuncture against other treatments. Two review authors independently extracted data and assessed risk of bias. We used odds ratio (OR) and mean difference for binary and continuous outcomes respectively. We combined data in meta-analyses where appropriate. Thirty-three trials were included. They recruited 2293 participants with insomnia, aged 15 to 98 years, some with medical conditions contributing to insomnia (stroke, end-stage renal disease, perimenopause, pregnancy, psychiatric diseases). They evaluated needle acupuncture, electroacupuncture, acupressure or magnetic acupressure.Compared with no treatment (two studies, 280 participants) or sham/placebo (two studies, 112 participants), acupressure resulted in more people with improvement in sleep quality (compared to no treatment: OR 13.08, 95% confidence interval (CI) 1.79 to 95.59; compared to sham/placebo: OR 6.62, 95% CI 1.78 to 24.55). However, when assuming that dropouts had a worse outcome in sensitivity analysis the beneficial effect of acupuncture was inconclusive. Compared with other treatment alone, acupuncture as an adjunct to other treatment might marginally increase the proportion of people with improved sleep quality (13 studies, 883 participants, OR 3.08, 95% CI 1.93 to 4.90). On subgroup analysis, only needle acupuncture but not electroacupuncture showed benefits. All trials had high risk of bias and were heterogeneous in the definition of insomnia, participant characteristics, acupoints and treatment regimen. The effect sizes were generally small with wide confidence intervals. Publication bias was likely present. Adverse effects were rarely reported and they were minor. Due to poor methodological quality, high levels of heterogeneity and publication bias, the current evidence is not sufficiently rigorous to support or refute acupuncture for treating insomnia. Larger high-quality clinical trials are required.

Lam W.W.,University of Hong Kong
Journal of clinical oncology : official journal of the American Society of Clinical Oncology | Year: 2013

Breast cancer (BC) decision aid (DA) randomized studies are limited to DA use in consultations among Western populations and for primary surgery. Their effectiveness beyond consultations, for reconstructive surgery and in other populations, has not been evaluated. We developed a DA administered after consultation for Chinese women deciding on BC surgery and, where relevant, immediate breast reconstruction, which was evaluated in this randomized controlled trial (RCT). Overall, 276 women considering BC surgery for early-stage BC were randomly assigned to receive a DA (take-home booklet) or the standard information booklet (control condition) after the initial consultation, wherein surgeons disclosed the diagnosis and discussed treatment options with patients. Using block random assignment by week, 138 women were assigned to the DA arm and 138 to the control arm. Participants completed interview-based questionnaires 1 week after consultation and then 1, 4, and 10 months after surgery. Primary outcome measures were decisional conflict, decision-making difficulties, BC knowledge 1 week after consultation, and decision regret 1 month after surgery. Secondary outcome measures were treatment decision, decision regret 4 and 10 months after surgery, and postsurgical anxiety and depression. The DA group reported significantly lower decisional conflict scores 1 week after consultation (P = .016) compared with women in the control arm. Women receiving the DA had significantly lower decision regret scores 4 (P = .026) and 10 months (P = .014) after surgery and lower depression scores 10 months after surgery (P = .001). This RCT demonstrated DAs may benefit Chinese patients in Hong Kong by reducing decisional conflict and subsequent regret and enhance clinical services for this population.

Wang L.,Harbin Engineering University | Wang Q.,Harbin Engineering University | Wang Q.,University of Hong Kong
IEEE Geoscience and Remote Sensing Letters | Year: 2013

Subpixel mapping (SPM) is a promising technique to increase the spatial resolution of land cover maps. Markov random field (MRF)-based SPM has the advantages of considering spatial and spectral constraints simultaneously. In the conventional MRF, only the spectral information of one observed coarse spatial resolution image is utilized, which limits the SPM accuracy. In this letter, supplementary information from subpixel shifted remote sensing images (SSRSI) is used with MRF to produce more accurate SPM results. That is, spectral information from SSRSI is incorporated into the likelihood energy function of MRF to provide multiple spectral constraints. Simulated and real images were tested with the subpixel/pixel spatial attraction model, Hopfield neural networks (HNNs), HNN with SSRSI, image interpolation then hard classification, conventional MRF, and proposed MRF with SSRSI based SPM methods. Results showed that the proposed method can generate the most accurate SPM results among these methods. © 2004-2012 IEEE.

Han G.,University of Hong Kong
IEEE Transactions on Information Theory | Year: 2015

Inspired by ideas from the field of stochastic approximation, we propose a randomized algorithm to compute the capacity of a finite-state channel with a Markovian input. When the mutual information rate of the channel is concave with respect to the chosen parameterization, the proposed algorithm proves to be convergent to the capacity of the channel almost surely with the derived convergence rate. We also discuss the convergence behavior of the algorithm without the concavity assumption. © 2015 IEEE.

Brownnutt M.,University of Innsbruck | Brownnutt M.,University of Hong Kong | Kumph M.,University of Innsbruck | Rabl P.,Vienna University of Technology | And 2 more authors.
Reviews of Modern Physics | Year: 2015

Electric-field noise near surfaces is a common problem in diverse areas of physics and a limiting factor for many precision measurements. There are multiple mechanisms by which such noise is generated, many of which are poorly understood. Laser-cooled, trapped ions provide one of the most sensitive systems to probe electric-field noise at MHz frequencies and over a distance range 30-3000 μm from a surface. Over recent years numerous experiments have reported spectral densities of electric-field noise inferred from ion heating-rate measurements and several different theoretical explanations for the observed noise characteristics have been proposed. This paper provides an extensive summary and critical review of electric-field noise measurements in ion traps and compares these experimental findings with known and conjectured mechanisms for the origin of this noise. This reveals that the presence of multiple noise sources, as well as the different scalings added by geometrical considerations, complicates the interpretation of these results. It is thus the purpose of this review to assess which conclusions can be reasonably drawn from the existing data, and which important questions are still open. In so doing it provides a framework for future investigations of surface-noise processes. © 2015 American Physical Society.

Cheung E.C.K.,University of Hong Kong
Queueing Systems | Year: 2011

In this paper a stochastic process involving two-sided jumps and a continuous downward drift is studied. In the context of ruin theory, the model can be interpreted as the surplus process of a business enterprise which is subject to constant expense rate over time along with random gains and losses. On the other hand, such a stochastic process can also be viewed as a queueing system with instantaneous work removals (or negative customers). The key quantity of our interest pertaining to the above model is (a variant of) the Gerber-Shiu expected discounted penalty function (Gerber and Shiu in N. Am. Actuar. J. 2(1):48-72, 1998) from ruin theory context. With the distributions of the jump sizes and their inter-arrival times left arbitrary, the general structure of the Gerber-Shiu function is studied via an underlying ladder height structure and the use of defective renewal equations. The components involved in the defective renewal equations are explicitly identified when the upward jumps follow a combination of exponentials. Applications of the Gerber-Shiu function are illustrated in finding (i) the Laplace transforms of the time of ruin, the time of recovery and the duration of first negative surplus in the ruin context; (ii) the joint Laplace transform of the busy period and the subsequent idle period in the queueing context; and (iii) the expected total discounted reward for a continuous payment stream payable during idle periods in a queue. © 2011 The Author(s).

Leung K.W.,Hong Kong University of Science and Technology | Wong A.S.,University of Hong Kong
Chinese Medicine | Year: 2010

The therapeutic potential of ginseng has been studied extensively, and ginsenosides, the active components of ginseng, are shown to be involved in modulating multiple physiological activities. This article will review the structure, systemic transformation and bioavailability of ginsenosides before illustration on how these molecules exert their functions via interactions with steroidal receptors. The multiple biological actions make ginsenosides as important resources for developing new modalities. Yet, low bioavailability of ginsenoside is one of the major hurdles needs to be overcome to advance its use in clinical settings. © 2010 Leung and Wong; licensee BioMed Central Ltd.

Kwong A.,University of Hong Kong
Chinese Clinical Oncology | Year: 2016

Genetic screening for hereditary breast and ovarian cancer (HBOC) has gained much attention for the past decades. With the development of advanced sequencing technology, other novel breast cancer associated susceptibility genes, other than BRCA genes, have been identified recently. The prevalence of BRCA mutation is known to be different in the West and in the East, therefore it is important to understand the mutation spectrum locally and in Asia to improve early diagnosis and clinical management of hereditary breast cancer in the region. In this editorial, we sought to highlight the need of genetic screening in HBOC, and also highlight specific issues within Asia which may need to be addressed to help popularize its appropriate use in this region. © Chinese Clinical Oncology.

Cheuk D.K.,University of Hong Kong
Cochrane database of systematic reviews (Online) | Year: 2011

Autism spectrum disorders (ASD) are characterized by impairment in social interaction, impairment in communication and lack of flexibility of thought and behavior. Acupuncture, which involves the use of needles or pressure to specific points on the body, is used widely in Traditional Chinese Medicine and increasingly within a western medical paradigm. It has sometimes been used as a treatment aimed at improving ASD symptoms and outcomes, but its clinical effectiveness and safety has not been rigorously reviewed. To determine the effectiveness of acupuncture for people with ASD in improving core autistic features, as well as communication, cognition, overall functioning and quality of life, and to establish if it has any adverse effects. We searched the following databases on 30 September 2010: CENTRAL (The Cochrane Library, 2010, Issue 3), MEDLINE (1950 to September 2010 Week 2), EMBASE (1980 to 2010 Week 38), PsycINFO, CINAHL, China Journal Full-text Database, China Master Theses Full-text Database, China Doctor Dissertation Full-text Database, China Proceedings of Conference Database, Index to Taiwan Periodical Literature System, metaRegister of Controlled Trials and the Chinese Clinical Trials Registry. We also searched AMED (26 February 2009) and Dissertation Abstracts International (3 March 2009), but these were no longer available to the authors or editorial base at the date of the most recent search. TCMLARS (Traditional Chinese Medical Literature Analysis and Retrieval System) was last searched on 3 March 2009. We included randomized and quasi-randomized controlled trials. We included studies comparing an acupuncture group with at least one control group that used no treatment, placebo or sham acupuncture treatment in people with ASD. We excluded trials that compared different forms of acupuncture or compared acupuncture with another treatment. Two review authors independently extracted trial data and assessed the risk of bias in the trials. We used relative risk (RR) for dichotomous data and mean difference (MD) for continuous data. We included 10 trials that involved 390 children with ASD. The age range was three to 18 years and the treatment duration ranged from four weeks to nine months. The studies were carried out in Hong Kong, mainland China and Egypt.Two trials compared needle acupuncture with sham acupuncture and found no difference in the primary outcome of core autistic features (RFRLRS total score: MD 0.09; 95% CI -0.03 to 0.21, P = 0.16), although results suggested needle acupuncture might be associated with improvement in some aspects of the secondary outcomes of communication and linguistic ability, cognitive function and global functioning.Six trials compared needle acupuncture plus conventional treatment with conventional treatment alone. The trials used different primary outcome measures and most could not demonstrate effectiveness of acupuncture in improving core autistic features in general, though one trial reported patients in the acupuncture group were more likely to have improvement on the Autism Behavior Checklist (RR 1.53; 95% CI 1.09 to 2.16, P = 0.02) and had slightly better post-treatment total scores (MD -5.53; 95% CI -10.76 to -0.31, P = 0.04). There was no evidence that acupuncture was effective for the secondary outcome of communication and linguistic ability, though there seemed to be some benefit for the secondary outcomes of cognitive function and global functioning.Two trials compared acupressure plus conventional treatment with conventional treatment alone and did not report on the primary outcome. Individual study results suggested there may be some benefit from acupressure for certain aspects of the secondary outcomes of communication and linguistic ability, cognitive function and global functioning.Four trials reported some adverse effects, though there was little quantitative information, and at times both intervention and control groups experienced them. Adverse effects noted included bleeding, crying due to fear or pain, irritability, sleep disturbance and increased hyperactivity. None of the trials reported on quality of life.There are a number of problems with the evidence base: the trials were few in number and included only children; six of the trials were at high risk of bias; they were heterogeneous in terms of participants and intervention; they were of short duration and follow-up; they reported inconsistent and imprecise results, and, due to carrying out large numbers of analyses, they were at risk of false positivity. Current evidence does not support the use of acupuncture for treatment of ASD. There is no conclusive evidence that acupuncture is effective for treatment of ASD in children and no RCTs have been carried out with adults. Further high quality trials of larger size and longer follow-up are needed.

Vavken P.,Harvard University | Samartzis D.,University of Hong Kong
Osteoarthritis and Cartilage | Year: 2010

Objective: The relative differences in effectiveness of subchondral stimulation, osteochondral grafts, and autologous chondrocyte implantation (ACI) are still unclear. It is the objective of this study to systematically review the literature on ACI compared to other treatments by clinical outcome and the quality of the repair tissue, including an assessment of the validity of these findings. Method: The online databases PubMed, EMBASE, Cochrane Controlled Trial Register, CENTRAL, CINAHL, and BioMed were searched. Controlled trials comparing ACI with other methods of cartilage repair or placebo were included. Data on clinical outcome and the quality of the repair tissue was abstracted in duplicate. Study validity was assessed by individual components (randomization, blinded outcome assessment, sample size, attrition, percentage biopsies). Results: Nine studies were included. The internal validity of most of these studies was poor. Studies comparing ACI with subchondral stimulation have a higher quality and show no differences in clinical outcomes, but suggest better results in tissue quality. The high quality evidence comparing ACI with osteochondral grafts shows better clinical outcomes and higher tissue quality after ACI. Conclusion: Among the included studies there is much inconsistency in methodological quality and findings. Regardless of these problems, the absolute differences between groups are fairly small, thus raising questions about their clinical importance. Future studies will be needed to answer the question of benefits of ACI compared to other treatments, and could profit from addressing and avoiding the problems seen in this group. Finally conclusions concerning long-term effects are still difficult. © 2010 Osteoarthritis Research Society International.

Chau M.,University of Hong Kong
ACM Transactions on Management Information Systems | Year: 2011

While the Web provides a lot of useful information to managers and decision makers in organizations for decision support, it requires a lot of time and cognitive effort for users to sift through a search result list returned by search engines to find useful information. Previous research in information visualization has shown that visualization techniques can help users comprehend information and accomplish information tasksmore efficiently and effectively. However, only a limited number of such techniques have been applied to Web search result visualization withmixed evaluation results. Using a design science approach, this research designed and implemented a glyph (a graphical object that represents the values of multiple dimensions using multiple visual parameters) and a system for visualizing Web search results. A flower metaphor was adopted in the glyph design to represent the characteristics and metadata of Web documents. Following the cognitive fit theory, an experimental study was conducted to evaluate three displays: a numeric display, a glyph display, and a combined display which showed numbers only, glyphs only, and both, respectively. Experimental results showed that the glyph display and the combined display performed better when task complexity was high, and the numeric display and the combined display performed better when task complexity was low. The combined display also received the best perceived usability from the subjects. Based on the findings, the implications of the study to research and practice are discussed and some future research directions are suggested. © 2011 ACM.

In China, sexual health and behaviors of young people have become a growing public concern but few studies have been conducted to investigate the prevalence and psychosocial correlates of the phenomenon. A self-reported questionnaire survey on youth sexual behaviors was conducted among 1,500 university students in 2011 at Hefei, a middle-size city in eastern China. A total of 1,403 students (age = 20.30 ± 1.27 years) completed the questionnaire with a high response rate of 93.5%. Among the respondents, 12.6% (15.4% of male versus 8.6% of female) students reported having pre-marital heterosexual intercourse; 10.8% (10.5% of males versus 11.2% females) had oral sex; 2.7% (3.4% of males versus 1.7% females) reported same-sex activities; 46% (70.3% of males versus 10.8% of females) reported masturbation behaviors; 57.4% (86.2% of males versus 15.6% females) students viewed pornography. In terms of sexual communication about sexual knowledge acquisition, 13.7% (10.7% of males versus 18% of females) talked to their parents about sex; 7.1% (6.1% of males versus 8.4% of females) students reported having conversation with parents on contraception. About forcing sexual behavior, 2.7% (4% of males versus 0.9% of females) reported forcing their sexual partners to have sex, and 1.9% (2.4% of males versus 1.2% of females) reported being forced to have sex. Gender was found to be significant predictor of sexual behaviors in university students: males reported more sexual behaviors including sexual fantasy, heterosexual intercourse, masturbation, viewing pornography and talking about sex with friends. Several correlates of sexual behaviors were identified for students of different gender separately. For males, having romantic relationships, past sex education experiences, low educational aspirations, time spent on the Internet, and urban native settings were significantly associated with more sexual behaviors. For female students, having romantic relationships and urban native settings predicted sexual behaviors. Sexual behavior among University students in China is not uncommon, although there are limited ways for students to acquire sex-related knowledge: male students showed significantly more sexual behaviors than female students. Having romantic relationships and more time spent online were important predictors of sexual behaviors among university students. To guide healthy sexual behaviors in young people, comprehensive sex education programs that provide necessary sexual health knowledge about safe sex should be developed and implemented in universities in China, particularly for students who have romantic relationships and those who spend long periods of time on the Internet.

The past decade has witnessed numerous publications on mesenchymal stem cells (MSC), which have great potential in regenerative medicine. MSC from various types of origins exhibit different characteristics, which may relate to the maintenance role of MSC in that specific source. Reports have emerged that among the most widely investigated sources, umbilical cord (UC) or umbilical cord blood (UCB) derived MSC throw advantages over bone marrow (BM) derived MSC due to their close to fetal origin. Here the methodologies used to separate MSC from UC or UCB, and the intrinsic properties, including proliferation capacity, multipotency, cytokine profile, cell surface protein expression and gene expression, between UC, UCB and BM derived MSC, are discussed in details, though may not in a full picture, for the first time.

Lee M.-C.,University of Hong Kong | Marx C.J.,Harvard University
Genetics | Year: 2013

It has increasingly been recognized that adapting populations of microbes contain not one, but many lineages continually arising and competing at once. This process, termed "clonal interference," alters the rate and dynamics of adaptation and biases winning mutations toward those with the largest selective effect. Here we uncovered a dramatic example of clonal interference between multiple similar mutations occurring at the same locus within replicate populations of Methylobacterium extorquens AM1. Because these mutational events involved the transposition of an insertion sequence into a narrow window of a single gene, they were both readily detectable at low frequencies and could be distinguished due to differences in insertion sites. This allowed us to detect up to 17 beneficial alleles of this type coexisting in a single population. Despite conferring a large selective benefit, the majority of these alleles rose and then fell in frequency due to other lineages emerging that were more fit. By comparing allele-frequency dynamics to the trajectories of fitness gains by these populations, we estimated the fitness values of the genotypes that contained these mutations. Collectively across all populations, these alleles arose upon backgrounds with a wide range of fitness values. Within any single population, however, multiple alleles tended to rise and fall synchronously during a single wave of multiple genotypes with nearly identical fitness values. These results suggest that alleles of large benefit arose repeatedly in failed "soft sweeps" during narrow windows of adaptation due to the combined effects of epistasis and clonal interference. © 2013 by the Genetics Society of America.

Hu R.-Z.,Chinese Academy of science | Zhou M.-F.,University of Hong Kong
Mineralium Deposita | Year: 2012

Mesozoic mineral deposits in South China include world-class deposits of W, Sn and Sb and those that provide the major sources of Ta, Cu, Hg, As, Tl, Pb, Zn, Au and Ag for the entire country. These deposits can be classified into polymetallic hydrothermal systems closely related to felsic intrusive rocks (Sn-W -Mo granites, Cu porphyries, polymetallic and Fe skarns, and polymetallic vein deposits) and low-temperature hydrothermal systems with no direct connection to igneous activities (MVT deposits, epithermal Au and Sb deposits). Recent studies have shown that they formed in the Triassic (Indosinian), Jurassic-Cretaceous (Early Yanshanian), and Cretaceous (Late Yanshanian) stages. Indosinian deposits include major MVT (Pb-Zn-Ag) deposits and granite-related W-Sn deposits. Early Yanshanian deposits are low-temperature Sb-Au and high-temperature W-Sn and Cu porphyry types. Many Late Yanshanian deposits are low-temperature Au-As-Sb-Hg and U deposits, and also include high-temperature W-Sn polymetallic deposits. The formation of these deposits is linked with a specific tectonothermal evolution and igneous activities. This special issue brings together some of the latest information in eight papers that deal with the origins and tectonic environments of mineral deposits formed in these stages. We anticipate that this issue will stimulate more interests in these ore deposits in South China. © 2012 Springer-Verlag.

Mok M.Y.,University of Hong Kong
International Journal of Rheumatic Diseases | Year: 2015

Dendritic cells (DCs) are antigen presenting cells that activate T cells and determine the outcome of immune response. In addition to their important function in defense against pathogens, DCs are increasingly recognized as playing a crucial role in the regulation of immune tolerance. Plasticity of DCs with different maturity status and functions enable them to be exploited as potential cell-based therapy to restore immune tolerance in autoimmune diseases. Various ex vivo methods have been developed to generate stable tolerogenic DCs that are able to induce and maintain regulatory T cell homeostasis. The beneficial effect of tolerogenic DCs have been studied in murine autoimmune models with promising results. Systemic lupus erythematosus (SLE) is a prototypic multi-systemic autoimmune disease characterized by autoantibody production and deposition of immune complexes in organs. There are evidences that dysregulated DCs play a pivotal role in the initiation and perpetuation of lupus disease. Peripheral blood monocytes in SLE patients were found to have active phenotype with accelerated differentiation into DCs efficient in antigen presentation. Plasmacytoid DCs in SLE patients produce high levels of interferon-alpha, the signature cytokine of this disease, that cause a positive feedback loop in the amplification of activation of innate and adaptive immunity. Furthermore, manipulation of DCs via toll-like receptor knockout in a murine lupus model leads to alteration in disease severity and survival. Thus, tolerogenic DCs may appear as a potential cell-based therapeutic option in SLE. © 2014 The Author. International Journal of Rheumatic Diseases published by Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Wong H.M.,University of Hong Kong
Journal of investigative and clinical dentistry | Year: 2012

To develop and validate an instrument, the Hong Kong Rapid Estimate of Adult Literacy in Dentistry (HKREALD-30). The Rapid Estimate of Adult Literacy in Dentistry (REALD-99) was translated into Chinese and modified in the pretest. A total of 200 parents of pediatric dental patients were interviewed using this modified scale and administered additional three sets of self-reported questionnaires. The 99 items of the scale were reduced to 30 (HKREALD-30). Concurrent validity was tested by comparing the HKREALD-30 scores with the participants' educational level, pattern of dental visits and reading habits. Convergent validity was tested by examining the association between HKREALD-30 and the Test of Functional Health Literacy in Dentistry (TOFHLiD). The test-retest reliability and internal consistency of HKREALD-30 were also evaluated. A significant correlation (P < 0.01) was found between HKREALD-30 and participants' reading habits. HKREALD-30 was also highly correlated with TOFHLiD (Spearman's rho = 0.693, P < 0.01). In the regression model, HKREALD-30 was positively associated with TOFHLiD (P < 0.05) after controlling for participants' characteristics. The intra-class correlation coefficient of HKREALD-30 was 0.78 and the Cronbach's alpha was 0.84. Initial testing of HKREALD-30 suggested that it is a valid and reliable instrument for the basic screening of oral health literacy among Chinese people in Hong Kong. © 2012 Blackwell Publishing Asia Pty Ltd.

Tse G.,University of Hong Kong
Journal of Arrhythmia | Year: 2016

Blood circulation is the result of the beating of the heart, which provides the mechanical force to pump oxygenated blood to, and deoxygenated blood away from, the peripheral tissues. This depends critically on the preceding electrical activation. Disruptions in the orderly pattern of this propagating cardiac excitation wave can lead to arrhythmias. Understanding of the mechanisms underlying their generation and maintenance requires knowledge of the ionic contributions to the cardiac action potential, which is discussed in the first part of this review. A brief outline of the different classification systems for arrhythmogenesis is then provided, followed by a detailed discussion for each mechanism in turn, highlighting recent advances in this area. © 2015 Japanese Heart Rhythm Society.

Liu R.-B.,Chinese University of Hong Kong | Yao W.,University of Hong Kong | Sham L.J.,University of California at San Diego
Advances in Physics | Year: 2010

We review the progress and main challenges in implementing large-scale quantum computing by optical control of electron spins in quantum dots (QDs). Relevant systems include self-assembled QDs of III-V or II-VI compound semiconductors (such as InGaAs and CdSe), monolayer fluctuation QDs in compound semiconductor quantum wells, and impurity centres in solids, such as P-donors in silicon and nitrogen-vacancy centres in diamond. The decoherence of the electron spin qubits is discussed and various schemes for countering the decoherence problem are reviewed. We put forward designs of local nodes consisting of a few qubits which can be individually addressed and controlled. Remotely separated local nodes are connected by photonic structures (microcavities and waveguides) to form a large-scale distributed quantum system or a quantum network. The operation of the quantum network consists of optical control of a single electron spin, coupling of two spins in a local nodes, optically controlled quantum interfacing between stationary spin qubits in QDs and flying photon qubits in waveguides, rapid initialization of spin qubits and qubit-specific single-shot non-demolition quantum measurement. The rapid qubit initialization may be realized by selectively enhancing certain entropy dumping channels via phonon or photon baths. The single-shot quantum measurement may be in situ implemented through the integrated photonic network. The relevance of quantum non-demolition measurement to large-scale quantum computation is discussed. To illustrate the feasibility and demand, the resources are estimated for the benchmark problem of factorizing 15 with Shor's algorithm. © 2010 Taylor & Francis.

Wang F.Y.,Nanjing University | Wang F.Y.,University of Hong Kong
Astronomy and Astrophysics | Year: 2013

The collapsar model of long gamma-ray bursts (GRBs) indicates that they may trace the star formation history, so long GRBs may be a useful tool for measuring the high-redshift star formation rate (SFR). The collapsar model explains GRB formation via the collapse of a rapidly rotating massive star with M > 30 M· into a black hole, which may imply a decrease in SFR at high redshift. However, we find that the Swift GRBs during 2005 to 2012 are biased when tracing the SFR, including a factor about (1 + z)0.5, which agrees with recent results. After taking this factor, the SFR derived from GRBs does not show a steep drop up to z ∼ 9.4. We consider the GRBs produced by rapidly rotating metal-poor stars with low masses to explain the high-redshift GRB rate excess. The chemically homogeneous evolution scenario (CHES) of rapidly rotating stars with mass higher than 12 M· is recognized as a promising path towards collapsars in connection with long GRBs. Our results indicate that the stars in the mass range 12 M· < M < 30 M· for low enough metallicity Z = 0.004 with the GRB efficiency factor 10-5 can fit the derived SFR with good accuracy. Combining these two factors, we find that the conversion efficiency from massive stars to GRBs is enhanced by a factor of 10, which may explain the excess of the high-redshift GRB rate. We also investigate the cosmic reionization history using the derived SFR. The GRB-inferred SFR would be sufficient to maintain cosmic reionization over 6 < z < 10 and reproduce the observed optical depth of Thomson scattering to the cosmic microwave background. © 2013 ESO.

Wu D.Y.,Leighton Center | Lam K.F.,University of Hong Kong
Clinical Orthopaedics and Related Research | Year: 2015

Level of Evidence: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.Conclusions: The osteodesis is a soft tissue nonosteotomy technique, and provided adequate deformity correction and improvement in AOFAS scores for patients with mild to moderate hallux valgus deformities, although a small number of the patients had postoperative stress fractures of the second ray develop. Future prospective studies should compare this technique with osteotomy techniques in terms of effectiveness of the correction, restoration of hallux function, complications, and long-term recurrence.Background: Although the etiology of hallux valgus is contested, in some patients it may be failure of the stabilizing soft tissue structures around the first ray of the foot. Because there is lack of effective soft tissue techniques, osteotomies have become the mainstream surgical approach to compensate for the underlying soft tissue deficiency; osteodesis, a soft tissue nonosteotomy technique, may be a third alternative, but its efficacy is unknown.Questions/purposes: We asked: (1) Can an osteodesis, a distal soft tissue technique, correct hallux valgus satisfactorily in terms of deformity correction and improvement in American Orthopaedic Foot and Ankle Society (AOFAS) score? (2) Is the effectiveness of an osteodesis affected by the patient’s age or deformity severity? (3) What complications are associated with this procedure?Methods: Between February and October 2010, we performed 126 operations to correct hallux valgus, of which 126 (100%) were osteodeses. Sixty-one patients (110 procedures) (87% of the total number of hallux valgus procedures) were available for followup at a minimum of 12 months (mean, 23 months; range, 12–38 months). This group formed our study cohort. During the study period, the general indications for this approach included failed conservative measures for pain relief and metatarsophalangeal angle greater than 20° or intermetatarsal angle greater than 9°. Intermetatarsal cerclage sutures were used to realign the first metatarsal and postoperative fibrosis was induced surgically between the first and second metatarsals to maintain its alignment. The radiologic first intermetatarsal angle, metatarsophalangeal angle, and medial sesamoid position were measured by Hardy and Clapham’s methods for deformity and correction evaluation. Clinical results were assessed by the AOFAS score.Results: The intermetatarsal angle was improved from a preoperative mean of 14° to 7° (p < 0.001; Cohen’s d = 1.8) at followup, the metatarsophalangeal angle from 31° to 18° (p < 0.001; Cohen’s d = 3.1), the medial sesamoid position from position 6 to 3 (p < 0.001; Cohen’s d = 2.4), and AOFAS hallux score from 68 to 96 points (p < 0.001). Neither patient age nor deformity severity affected the effectiveness of the osteodesis in correcting all three radiologic parameters; however, the deformities treated in this series generally were mild to moderate (mean intermetatarsal angle, 14°; range, 9°–22°). There were six stress fractures of the second metatarsal (5%), five temporary metatarsophalangeal joint medial subluxations all resolved in one month by the taping-reduction method without surgery, and six metatarsophalangeal joints with reduced dorsiflexion less than 60°. © 2014, The Association of Bone and Joint Surgeons®.

This study examines why compact organizational space may matter for technological catch-up, through a comparison of China's leading automotive groups. The comparative analysis demonstrates that the Shanghai Automotive Industry Corporation (SAIC) surpasses its two local rivals in terms of technological capabilities partly because the firm has managed its organizational space in close connection with intensive growth strategies at the group level. SAIC has greatly benefited from compact organizational space in building technological capabilities, as it encourages the mobilization and integration of internal resources and promotes group-wide synergy for an effective internalization of acquired assets. © 2014 Elsevier B.V. All rights reserved.

Jim C.Y.,University of Hong Kong
Applied Energy | Year: 2015

Thermal performance of greenwalls, a critical and common concern, is regulated by solar irradiance vis-à-vis orientation and shading. A field experiment was conducted in humid-tropical Hong Kong to address the research question under typical summer-weather scenarios: sunny, cloudy and rainy. On a large circular concrete tank, climber-greenwall experimental plots were established with duplication in four cardinal compass directions. Air and infrared-radiometer surface temperature sensors monitored at different greenwall positions: ambient-air (control), bare-concrete-surface (control), vegetation-surface, behind-mesh-airgap, and behind-mesh-concrete surface. Pyranometers were installed vertically at four orientations and horizontally at tank-top (control) to monitor solar-energy input. Habitat verticality induces notable variations in solar-energy capture at four orientations by daily total, peak level, intensity, duration and timing. On sunny day, solar fraction reaching east side was only 37.1% of tank-top. Early morning sunshine striking east side nearly perpendicularly brings maximum intensity. South side facing the sun but at tangential incident angle has only 23.3% reception. Strong irradiance drives high control-surface temperature, but also induces notable vegetation-surface and adjacent ambient-air cooling by transpiration. A threshold solar intensity of about 300Wm-2 is necessary to impart notable cooling-effect. Summer-sunny day and rainy-day sunshine-burst episodes could satisfy this condition; cloudy day and rainfall periods with attenuated-diffused sunlight could not. Cloudy day and rainfall periods suppress cooling differences by orientation. Behind-mesh concrete surface is consistently cooler than control concrete surface in the three summer-weather scenarios. Behind-mesh-air remains warmer than ambient-air but cooler than two adjoining surfaces (vegetation and behind-mesh-concrete), indicating air-barrier effect and restricted air exchange between ambience and airgap. It implies that greenwall can bring bidirectional cooling, but transpiration cooling of anterior (ambient) air is more effective than shading and thermal-insulation cooling of posterior (airgap) air and concrete-surface. The findings could inform greenwall design to enhance ecosystem services for climate-change adaption and urban heat island amelioration. © 2015 Elsevier Ltd.

Yan W.M.,University of Hong Kong | Li X.S.,Hong Kong University of Science and Technology
Geotechnique | Year: 2011

This paper presents a thermodynamically consistent constitutive model for natural soils with bonds. In the model, the free energy (the internal energy available to do work) is contributed partly by the so-called frozen or locked energy, whose evolution is assumed to be homogeneously related to the irrecoverable deformation. During loading, the bonds existing in the natural soil not only boost the dissipation rate but also liberate certain historically accumulated locked energy. Such effects, however, are diminished as loading proceeds and the bonds are destroyed. The novel aspect of the present model is that it accommodates both the Mohr-Coulomb and critical-state failure modes, and the two modes are unified through the evolution law of a thermodynamic force associated with the locked bonding energy. As compared with the classical Cam-clay models, the model contains two additional material constants, where one is proposed by Collins & Kelly to improve the shape of the yield surface, and the other is dedicated to bonding evolution. The calibration procedure for the material parameters is provided. The capability of the model is demonstrated by a series of model simulations on a hypothetical bonded soil under various triaxial loading paths, and the model response is also compared with representative testing results in the literature.

Xu X.,University of Washington | Yao W.,University of Hong Kong | Xiao D.,Carnegie Mellon University | Heinz T.F.,Columbia University
Nature Physics | Year: 2014

The recent emergence of two-dimensional layered materials-in particular the transition metal dichalcogenides-provides a new laboratory for exploring the internal quantum degrees of freedom of electrons and their potential for new electronics. These degrees of freedom are the real electron spin, the layer pseudospin, and the valley pseudospin. New methods for the quantum control of the spin and these pseudospins arise from the existence of Berry phase-related physical properties and strong spin-orbit coupling. The former leads to the versatile control of the valley pseudospin, whereas the latter gives rise to an interplay between the spin and the pseudospins. Here, we provide a brief review of both theoretical and experimental advances in this field. © 2014 Macmillan Publishers Limited.

Coralliophaga lithophagella is a nestler of basaltic rocks in the deeper waters (~57-360m) of the Açores and of shallower limestone karst in the Mediterranean where it predominately occurs in empty lithophagine burrows. In the Açores, because of low oceanic productivity and the basaltic, un-boreable, substratum, C.lithophagella is but 50% the shell length of continental European conspecifics and the shell's postero-dorsal margin is growth elevated to enhance particle capture. This is also achieved with relatively enormous ctenidia, minute labial palps and a simplified intestine. Unusually amongst the Trapezidae, C.lithophagella is abyssate and the foot is reduced. Also atypically, and during ontogeny, the shell enlarges postero-dorsally to facilitate particle capture. Anatomical features of the representatives of the constituent genera of the Trapezidae are compared one with another and with Arctica islandica (Arcticidae), the constituent families of the Arcticoidea. It is concluded that the Trapezidae constitutes a discrete clade of epibenthic nestlers, possibly descended from an endobenthic arcticoid ancestor, and showing a trend towards a reduction in shell and hinge complexity. The status of Fluviolanatus subtorta with mantle margins filled with single-celled algae and putatively assigned to the Trapezidae, awaits molecular confirmation. © 2014 Elsevier Ltd.

Zhang X.,University of Hong Kong
Habitat International | Year: 2011

Implementing international projects in a foreign country is a high risk business activity. Research on this subject has tended to emphasize traditional risks. However, an emerging new type of " social risk" in the globalization era has been ignored. With the rapid urbanization progress in China, many international contractors have entered the Chinese construction market due to the huge demand in the market. However, the differences in the social, economic and cultural backgrounds among the international contractors and their partners have led to difficulties and occasional disputes among various participants. In particular, they are presented with various social risks in a new environment. This paper identifies the key social risk factors associated with international contractors from a questionnaire survey and case study. The social risks highlighted from the questionnaire survey include " local protectionism (for local projects)" , " risk of poor social relations between various parties in the local region" , " permit or license risk in dealing with land use and construction planning issues due to policy changes" and " dispute risk with local construction labor" Several risk response strategies for international contractors are also illustrated by the case study from China. Suggestions developed in the case study can provide useful references to those international contractors who have entered or are planning to operate their businesses in China. © 2011 Elsevier Ltd.

Gu Y.-Y.,China University of Petroleum - East China | Yeung A.T.,University of Hong Kong
Journal of Hazardous Materials | Year: 2011

The sorption/desorption characteristics of heavy metals onto/from soil particle surfaces are the primary factors controlling the success of the remediation of heavy-metal contaminated soils. These characteristics are pH-dependent, chemical-specific, and reversible; and can be modified by enhancement agents such as chelates and surfactants. In this study, batch experiments were conducted to evaluate the feasibility of using citric acid industrial wastewater (CAIW) to desorb cadmium from a natural clay from Shanghai, China at different soil mixture pHs. It can be observed from the results that the proportion of cadmium desorbed from the soil using synthesized CAIW is generally satisfactory, i.e., >60%, when the soil mixture pH is lower than 6. However, the proportion of desorbed cadmium decreases significantly with increase in soil mixture pH. The dominant cadmium desorption mechanism using CAIW is the complexion of cadmium with citric acid and acetic acid in CAIW. It is concluded that CAIW can be a promising enhancement agent for the remediation of cadmium-contaminated natural soils when the environmental conditions are favorable. As a result, CAIW, a waste product itself, can be put into productive use in soil remediation. © 2011 Elsevier B.V.

Chan C.C.,University of Hong Kong | Bouscayrol A.,Lille University of Science and Technology | Chen K.,Lille University of Science and Technology
IEEE Transactions on Vehicular Technology | Year: 2010

With the advent of more stringent regulations related to emissions, fuel economy, and global warming, as well as energy resource constraints, electric, hybrid, and fuel-cell vehicles have attracted increasing attention from vehicle constructors, governments, and consumers. Research and development efforts have focused on developing advanced powertrains and efficient energy systems. This paper reviews the state of the art for electric, hybrid, and fuel-cell vehicles, with a focus on architectures and modeling for energy management. Although classic modeling approaches have often been used, new systemic approaches that allow better understanding of the interaction between the numerous subsystems have recently been introduced. © 2010 IEEE.

Zuo P.,University of Hong Kong
Current issues in molecular biology | Year: 2010

This article describes a one-step procedure based on Taq polymerase for the precise assembly of DNA fragments into circular constructs as long as 6 kb. The only prior step needed was the amplification of the gene to be cloned and the linear vector backbone, and the whole process up to assembly and circularization lasted only 2 days, compared with the conventional method's 2 weeks. Furthermore, the final DNA construct was used to transform Escherichia coli directly without any further treatment. By circumventing the need for DNA ligase, our "Quick Assemble" method offers an improvement over the combination of long PCR and overlap extension PCR, and is expected to facilitate various kinds of complex genetic engineering projects that require precise in-frame assembly of multiple fragments, such as multiple site-directed mutagenesis and whole-DNA library gene shuffling, as well as the construction of new plasmids with any promoter, resistance gene marker, restriction site, or any DNA tag.

Chou K.-L.,University of Hong Kong
American Journal of Geriatric Psychiatry | Year: 2010

OBJECTIVE: Depressive symptoms, which are both common and heritable, are important indicators of the extent of general well-being and health in old age. Identifying risk factors for depressive symptoms may lead to improved intervention and effective prevention. Both the presence of the apolipoprotein (APOE) genotype and loneliness are associated with later life symptoms of depression, and all three share a neuroendocrine signature, namely altered activity in the hypothalamic-pituitary-adrenal axis. The authors expected a positive association of loneliness with depressive symptoms, a negative link between APOE ε2 with depressive symptoms, and a significant genotype-environment interaction between loneliness (the social environment) and APOE ε2 on symptoms of depression. DESIGN: This was a cross-sectional observational study. SETTING AND PARTICIPANTS: A population-based sample of 979 Chinese people from Taiwan aged 54 years and older was examined. MEASUREMENTS: A short-form of the Center for Epidemiologic Studies of Depression Scale was used and the genotype of APOE was obtained. RESULTS: The interaction between loneliness and APOE ε2 was found to be negatively associated with depressive symptoms in adjusted regression models. Loneliness was also positively correlated with symptoms of depression. CONCLUSIONS: These data suggest that the APOE ε2 genotype decreases vulnerability to symptoms of depression in the presence of a social stressor, namely loneliness in this case, and has implications for the enhancement of well-being among older adults. Future studies are needed to delineate the mechanism underlying this gene-environment interaction. © 2010 American Association for Geriatric Psychiatry.

Bohmer C.G.,University College London | Harko T.,University of Hong Kong | Lobo F.S.N.,University of Lisbon
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In this work, we explore the possibility that static and spherically symmetric traversable wormhole geometries are supported by modified teleparallel gravity or f(T) gravity, where T is the torsion scalar. Considering the field equations with an off-diagonal tetrad, a plethora of asymptotically flat exact solutions are found, which satisfy the weak and the null energy conditions at the throat and its vicinity. More specifically, considering T=0, we find the general conditions for a wormhole satisfying the energy conditions at the throat and present specific examples that satisfy the energy conditions throughout the spacetime. As a consistency check, we also verify that in the teleparallel equivalent of general relativity, i.e., f(T)=T, one regains the standard general relativistic field equations for wormhole physics. Furthermore, considering specific choices for the f(T) form and for the redshift and shape functions, several solutions of wormhole geometries are found that satisfy the energy conditions at the throat and its neighborhood. As in their general relativistic counterparts, these f(T) wormhole geometries present far-reaching physical and cosmological implications, such as being theoretically useful as shortcuts in spacetime and for inducing closed timelike curves, possibly violating causality. © 2012 American Physical Society.

Direction of self-motion during walking is indicated by multiple cues, including optic flow, nonvisual sensory cues, and motor prediction. I measured the reliability of perceived heading from visual and nonvisual cues during walking, and whether cues are weighted in an optimal manner. I used a heading alignment task to measure perceived heading during walking. Observers walked toward a target in a virtual environment with and without global optic flow. The target was simulated to be infinitely far away, so that it did not provide direct feedback about direction of self-motion. Variability in heading direction was low even without optic flow, with average RMS error of 2.4°. Global optic flow reduced variability to 1.9°-2.1°, depending on the structure of the environment. The small amount of variance reduction was consistent with optimal use of visual information. The relative contribution of visual and nonvisual information was also measured using cue conflict conditions. Optic flow specified a conflicting heading direction (±5°), and bias in walking direction was used to infer relative weighting. Visual feedback influenced heading direction by 16%-34% depending on scene structure, with more effect with dense motion parallax. The weighting of visual feedback was close to the predictions of an optimal integration model given the observed variability measures.© 2014 ARVO.

Obesity is closely associated with various cardiovascular diseases (CVDs). Adipose tissue inflammation and perturbation of adipokine secretion may contribute to the pathogenesis of CVD. This study aimed to evaluate whether the 2 most abundant adipokines, adipocyte-fatty acid binding protein (A-FABP) and adiponectin, are independent risk factors predisposing to CVD. We investigated prospectively the 12-year development of CVD in relation to the baseline levels of A-FABP and adiponectin in a population-based community cohort comprising 1847 Chinese subjects recruited from the Hong Kong Cardiovascular Risk Factors Prevalence Study 2 (CRISPS 2) cohort without previous CVD. Baseline serum levels of A-FABP, adiponectin, and C-reactive protein (CRP), an established biomarker predictive of CVD, were measured. In all, 182 (9.9%) of the 1847 Chinese subjects developed CVD during a median follow-up of 9.4 years. The CVD group had more traditional risk factors, higher baseline levels of A-FABP and CRP (both P<0.001), but similar adiponectin levels (P=0.881) compared with the non-CVD group. In Cox regression analysis including both biomarkers, the adjusted HR for A-FABP and CRP for subjects above the optimal cutoff values were 1.57 (95% CI, 1.14 to 2.16; P=0.006) and 1.60 (95% CI, 1.12 to 2.27; P=0.01), respectively, after adjustment for traditional risk factors. The category-free net reclassification index, but not the c-statistic, showed improvement in predictive performance by the addition of A-FABP to the traditional risk factor model (P=0.017). Circulating A-FABP level predicts the development of CVD after adjustment for traditional risk factors in a community-based cohort. Its clinical use for CVD prediction warrants further validation.

Rivera-Diaz-Del-Castillo P.E.J.,University of Cambridge | Huang M.,University of Hong Kong
Acta Materialia | Year: 2012

Irreversible thermodynamics is employed as a framework to describe plastic deformation in pure metals and alloys. Expressions to describe saturation stress in single crystals and nanocrystals are employed over wide ranges of temperature, strain rate and grain size. The importance of the roles played by vacancy self-diffusion in dislocation climb and in plasticity is shown. Equations to describe the stress-strain response of single crystals and ultrafine-grained metals are derived. The activation energy for dislocation annihilation plays a central role in the mechanical response of the systems. Succinct formulations for predicting hot deformation behaviour and relaxation of industrial alloys are presented; the influence of composition in the activation energy for dislocation annihilation is shown. All formulations describing stress-strain relationships can be reduced to Kocks-Mecking classical formulation, but incorporating grain size and compositional effects. The importance of the recovery term in such formulation is established, as well as the need to obtain it employing more fundamental approaches. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Chou K.-L.,University of Hong Kong
Journals of Gerontology - Series B Psychological Sciences and Social Sciences | Year: 2010

Objectives. This study examined financial transfers from adult children to elderly parents in Hong Kong and tested three hypotheses about the motives for such transfers. We address previous research, suggesting that family financial support for retirees will decline in the coming decades as a consequence of the reduction in the fertility rate; we also examine whether financial transfers are a function of the number of adult children in the family. Methods. We used multiple regression models based on data from a representative sample of parents aged 60 years and older to identify the correlates of the amount of transfers from adult children to their elderly parents. Results. We found evidence for the hypothesis that upstream transfers to elderly parents are their way of withdrawing savings from a "support bank" in which they made contribution for their children's education earlier in life and that transfers are altruistic in nature, but our results provide only moderate support to the old age security hypothesis that perceives family as a source of capital. Discussion. The number of children has a ceiling effect on transfers, which calls into question common assumptions about the extent to which the decline in fertility will pose a severe threat to the extent of familial support of older persons over the coming decades.

Shen B.,Donghua University | Wang Z.,Donghua University | Wang Z.,Brunel University | Hung Y.S.,University of Hong Kong
Automatica | Year: 2010

This paper is concerned with a new distributed H∞-consensus filtering problem over a finite-horizon for sensor networks with multiple missing measurements. The so-called H∞-consensus performance requirement is defined to quantify bounded consensus regarding the filtering errors (agreements) over a finite-horizon. A set of random variables are utilized to model the probabilistic information missing phenomena occurring in the channels from the system to the sensors. A sufficient condition is first established in terms of a set of difference linear matrix inequalities (DLMIs) under which the expected H∞-consensus performance constraint is guaranteed. Given the measurements and estimates of the system state and its neighbors, the filter parameters are then explicitly parameterized by means of the solutions to a certain set of DLMIs that can be computed recursively. Subsequently, two kinds of robust distributed H∞-consensus filters are designed for the system with norm-bounded uncertainties and polytopic uncertainties. Finally, two numerical simulation examples are used to demonstrate the effectiveness of the proposed distributed filters design scheme. © 2010 Elsevier Ltd. All rights reserved.

Kwok S.,University of Hong Kong
Publications of the Astronomical Society of Australia | Year: 2010

Since various structural components of planetary nebulae (PN) manifest themselves differently, a combination of optical, infrared, submillimetre and radio techniques is needed to derive a complete picture of planetary nebulae. The effects of projection can also make derivation of the true 3-D structure difficult. Using a number of examples, we show that bipolar and multipolar nebulae are much more common than usually inferred from morphological classifications of apparent structures of planetary nebulae. We put forward a new hypothesis that the bipolar and multipolar lobes of PN are not regions of high-density ejected matter, but the result of ionization and illumination. The visible bright regions are in fact volumes of low density (cleared by high-velocity outflows), through which UV photons are being channelled. We suggest that multipolar nebulae with similar lobe sizes are not caused by simultaneous ejection of matter in several directions, but by leakage of UV photons in those directions. © Astronomical Society of Australia 2010.

This paper investigates linear systems with polynomial dependence on time-invariant uncertainties constrained in the simplex via homogeneous parameter-dependent quadratic Lyapunov functions (HPD-QLFs). It is shown that a sufficient condition for establishing whether the system is either stable or unstable can be obtained by solving a generalized eigenvalue problem. Moreover, this condition is also necessary by using a sufficiently large degree of the HPD-QLF. © 2009 Elsevier Ltd. All rights reserved.

Saunders R.M.K.,University of Hong Kong
Biological Reviews | Year: 2010

The recent publication of hypotheses explaining the homeotic control of floral organ identity together with the availability of increasingly comprehensive and well-resolved molecular phylogenies presents an ideal opportunity for reassessing current knowledge of floral diversity and evolution in the Annonaceae. This review summarizes currently available information on selected aspects of floral structure and function, including: changes in the number of perianth whorls and the number of perianth parts per whorl; the evolution of sympetaly; the diversity and evolution of pollination chambers (with a novel classification of seven main structural forms of floral chamber based on the different arrangement, size and shape of petals); the evolution of perianth glands; floral unisexuality and hypotheses explaining the unexpectedly high frequency of occurrence of androdioecy; the origin and possible function of inner and outer staminodes; the evolution of stamen connective diversity and theca septation; and the origin of 'true' syncarpy and functionally equivalent extragynoecial compita. In each case, current ideas on the origin, evolution and function are discussed. The information presented in this review enables two main conclusions to be drawn. The first is that changes in the homeotic control of floral organ identity may have had a profound impact on floral structure in several disparate lineages in the family. This is most obvious in Fenerivia, in which a centrifugal shift of floral organ identity has occurred, and in Dasymaschalon, in which a reverse (centripetal) shift has occurred. Other genera that have gained or lost entire perianth whorls are likely to have undergone similar homeotic changes. Attention is also drawn to the extensive functional convergence in Annonaceae flowers, with widespread homoplasy in many characters that have previously been emphasized in higher-level classifications. © 2009 Cambridge Philosophical Society.

Lo S.H.,University of Hong Kong
International Journal for Numerical Methods in Engineering | Year: 2013

A generic algorithm is proposed to merge arbitrary solid tetrahedral meshes automatically into one single valid finite element mesh. The intersection segments in the form of distinct nonoverlapping loops between the boundary surfaces of the given solid objects are determined by the robust neighbor tracing technique. Each intersected triangle on the boundary surface will be triangulated to incorporate the intersection segments onto the boundary surface of the objects. The tetrahedra on the boundary surface associated with the intersected triangular facets are each divided into as many tetrahedra as the number of subtriangles on the triangulated facet. There is a natural partition of the boundary surfaces of the solid objects by the intersection loops into a number of zones. Volumes of intersection can now be identified by collected bounding surfaces from the surface patches of the partition. Whereas mesh compatibility has already been established on the boundary of the solid objects, mesh compatibility has yet to be restored on the bounding surfaces of the regions of intersection. Tetrahedra intersected by the cut surfaces are removed, and new tetrahedra can be generated to fill the volumes bounded by the cut surfaces and the portion of cavity boundary connected to the cut surfaces to restore mesh compatibility at the cut surfaces. Upon restoring compatibility on the bounding surfaces of the regions of intersection, the objects are ready to be merged together as all regions of intersection can be detached freely from the objects. All operations, besides the determination of intersections structurally in the form of loops, are virtually topological, and no parameter and tolerance is needed in the entire merging process. Examples are presented to show the steps and the details of the mesh merging procedure. © 2012 John Wiley & Sons, Ltd.

Chu C.H.,University of Hong Kong
Oral health & preventive dentistry | Year: 2012

To describe the tooth status, periodontal status, oral hygiene and snacking habits of children in four villages in northeastern Myanmar. This was a cross-sectional study using a convenient sampling protocol. All children ages 5 and 12 years from four villages were examined by an experienced epidemiologist, and the status of their primary and permanent dentition, respectively, was reported using the diagnostic criteria recommended by the World Health Organisation. A parental questionnaire survey was performed to study the children's habits. A total of 95 5-year-old and 80 12-year-old children were examined. It was found that 94% and 39% of the 5- and 12-year-old children, respectively, had never brushed their teeth. Few children had snacking habits. Most of the children - 75% of the 5-year-olds and 85% of the 12-year-olds - had no caries experience. The mean dmft score of the 5-year-olds was 0.9, while the mean DMFT score of the 12-year-olds was 0.2. Signs of moderate to severe gingivitis were found in 42% of the 5-year-olds, and 40% of the 12-year-olds had dental calculus. The prevalence and severity of dental caries among the children in the four villages in northeastern Myanmar was low. Their oral hygiene habits and periodontal conditions were not satisfactory and need to be improved.

Hui E.C.,University of Hong Kong
Journal of Medicine and Philosophy | Year: 2010

The healthcare crisis that has developed in the last two decades during China's economic reform has caused healthcare and hospital financing reforms to be largely experienced by patients as a crisis in the patient-healthcare professional relationship (PPR) at the bedside. The nature and magnitude of this crisis were epitomized by the "Harbin Scandal" - an incident that took place in August 2005 in a Harbin teaching hospital in which the family of an elderly patient hospitalized in the intensive care unit (ICU) for 66 days paid over RMB ¥6 million. The news was publicized globally and ended in the firing of six top hospital administrators including the hospital president and the ICU director. This paper seeks to show that the Chinese healthcare crisis is ultimately linked to a conflict of interests between patients and healthcare professionals (HCPs), which is inherent in the reformed healthcare system of China. Hence the crisis is, at its core, a crisis of fidelity and confidence that must be restored to the PPR. At the "macro" level, it is simplistic to blame the crisis on the failure of the market system, and at the "micro" level, it is naïve to expect that a contractual understanding of the PPR will effectively restore the confidence of patients. This paper will show that the fiduciary relationship and medical professionalism share similar attributes, with fidelity being the core value of both. It concludes that the loss of medical fidelity implies the dissolution of the PPR and the demise of the medical profession and challenges Chinese HCPs to keep their fidelity as a means to both protect their patients' interests and to preserve their profession's survival. © The Author 2010.

Au S.L.,University of Hong Kong
Frontiers of medicine | Year: 2013

Hepatocellular carcinoma (HCC) development is characterized by the presence of epigenetic alterations, including promoter DNA hypermethylation and post-translational modifications of histone, which profoundly affect expression of a wide repertoire of genes critical for cancer development. Emerging data suggest that deregulation of polycomb group (PcG) proteins, which are key chromatin modifiers repressing gene transcription during developmental stage, plays a causative role in oncogenesis. PcG proteins assemble into polycomb repressive complex 1 (PRC1) and polycomb repressive complex 2 (PRC2) to impose the histone H3 lysine 27 trimethylation (H3K27me3) modification for repression. In this review, we will first recapitulate the mechanisms of two key epigenetic pathways: DNA methylation and histone modifications. Specifically, we will focus our discussion on the molecular roles of PcG proteins. Next, we will highlight recent findings on PcG proteins, their clinicopathological implication and their downstream molecular consequence in hepatocarcinogenesis. Last but not least, we will consider the therapeutic potential of targeting enhancer of zeste homolog 2 (EZH2) as a possible treatment for HCC. Improving our understanding on the roles of PcG proteins in hepatocarcinogenesis can benefit the development of epigenetic-based therapy.

Lo E.C.,University of Hong Kong
Advances in dental research | Year: 2012

Professionally applied topical fluoride varnish, gel, and solution have been shown to be effective in preventing and in arresting dental caries. Their use in different countries in Asia varies greatly and may not correlate with the dental caries situation of the populations in the countries. In the higher-income countries, use of fluoride varnish and gel is common among dental professionals. In contrast, the use of professionally administered topical fluorides is not common in the lower-income countries. Fluoride varnish, being easy to apply and safe, has been the preferred agent for the prevention of early childhood caries, which is prevalent in many developing countries in Asia. The relatively high cost of professionally administered fluoride agents and the shortage of a dental workforce, especially in lower income countries, have hampered the widespread adoption of these effective caries prevention methods in the private and public dental services. Government health policies should be pursued to lower the cost of treatment, either through incentives for local production and/or elimination of taxes and tariffs on imported fluoride products.

Sheng G.-P.,Hefei University of Technology | Yu H.-Q.,Hefei University of Technology | Li X.-Y.,University of Hong Kong
Biotechnology Advances | Year: 2010

A review concerning the definition, extraction, characterization, production and functions of extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment reactors is given in this paper. EPS are a complex high-molecular-weight mixture of polymers excreted by microorganisms, produced from cell lysis and adsorbed organic matter from wastewater. They are a major component in microbial aggregates for keeping them together in a three-dimensional matrix. Their characteristics (e.g., adsorption abilities, biodegradability and hydrophilicity/hydrophobicity) and the contents of the main components (e.g., carbohydrates, proteins, humic substances and nucleic acids) in EPS are found to crucially affect the properties of microbial aggregates, such as mass transfer, surface characteristics, adsorption ability, stability, the formation of microbial aggregates etc. However, as EPS are very complex, the knowledge regarding EPS is far from complete and much work is still required to fully understand their precise roles in the biological treatment process. © 2010 Elsevier Inc.

Han G.,University of Hong Kong
IEEE International Symposium on Information Theory - Proceedings | Year: 2013

Inspired by the ideas from the field of stochastic approximation, we propose a randomized algorithm to compute the capacity of a finite-state channel with a Markovian input. When the mutual information rate of the channel is concave with respect to the chosen parameterization, we show that, at least for some practical channels, the proposed algorithm will converge to the capacity almost surely. © 2013 IEEE.

Cheung B.M.Y.,University of Hong Kong
Journal of Cardiovascular Pharmacology | Year: 2010

Hypertension and type 2 diabetes are both common chronic conditions that affect a major proportion of the general population. They tend to occur in the same individual, suggesting common predisposing factors, which can be genetic or environmental. Although the genes causing hypertension or diabetes await elucidation, the environmental causes of these diseases are well known. Obesity and physical activity are the 2 leading factors that predispose to both diseases. Individuals with abdominal obesity are likely to develop lipid abnormalities and elevation of blood pressure and glucose. In time, hypertension and diabetes ensue. Because of the shared etiology, there is substantial overlap between hypertension and diabetes. In the Hong Kong Cardiovascular Risk Factor Prevalence Study, 40% of the subjects in the community had either raised blood pressure or raised blood glucose. Only 42% of people with diabetes had normal blood pressure and only 56% of people with hypertension had normal glucose tolerance. The presence of hypertension or diabetes should alert the clinician to the possibility of the other condition. Obesity, lipid abnormalities, raised blood pressure, and glucose are all components of the metabolic syndrome. The syndrome therefore implies a pathologic process, which is potentially reversible in the early stages. Previous efforts targeting smoking, hypertension, and hypercholesterolemia have started to bear fruit. However, obesity is on the increase in developed and developing countries. It is now time to focus on obesity and the metabolic syndrome, which require more a public health than a pharmacologic approach. © 2010 by Lippincott Williams & Wilkins.

Chou K.-L.,University of Hong Kong | Afifi T.O.,University of Manitoba
American Journal of Epidemiology | Year: 2011

The authors' objective in this study was to examine the role of disordered gambling as a risk factor for the subsequent occurrence of specific Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I psychiatric disorders after adjusting for medical conditions, health-related quality of life, and stressful life events. Community-dwelling respondents from nationally representative US samples (n = 33,231) were interviewed in 2000-2001 and 2004-2005. Past-year disordered gambling at baseline was associated with the subsequent occurrence of any Axis I psychiatric disorder, any mood disorder, bipolar disorder, generalized anxiety disorder, posttraumatic stress disorder, any substance use disorder, alcohol use disorders, and alcohol dependence disorder after adjustment for sociodemographic variables. After simultaneous adjustment for medical conditions, health-related quality of life, and recent stressful life events, disordered gambling remained significantly related to any mood disorder, generalized anxiety disorder, posttraumatic stress disorder, alcohol use disorders, and alcohol dependence. The clinical implications of these findings are that treatment providers need to screen gambling patients for mood, anxiety, and substance use problems and monitor the possible development of later comorbid conditions. © 2011 The Author.

Vanhoutte P.M.,University of Hong Kong
Cardiovascular Drugs and Therapy | Year: 2010

The endothelium mediates relaxations (dilatations) of the underlying vascular smooth muscle cells. The endothelium-dependent relaxations are due to the release of non-prostanoid vasodilator substances. The best characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO). The endothelial cells also release substances (endothelium-derived hyperpolarizing factor, EDHF) that cause hyperpolarization of the cell membrane of the underlying vascular smooth muscle. The release of EDRF from the endothelium can be mediated by both pertussis toxin-sensitive Gi (alpha2-adrenergic activation, serotonin, thrombin) and insensitive Gq (adenosine diphosphate, bradykinin) coupling proteins. The ability of the endothelial cell to release relaxing factors can be upregulated by impregnation with estrogens, exercise and antioxidants, and down-regulated by oxidative stress and increased presence of oxidized LDL. Following injury or apoptotic death, the endothelium regenerates. However, in regenerated endothelial cells, there is an early selective loss of the pertussis-toxin sensitive mechanisms of EDRF-release. Functional studies suggest that abnormal handling of LDL because of increased oxidative stress play a key role in this selective loss. Genomic analysis demonstrates the emergence of fatty acid binding protein-A (A-FBP) and metalloproteinase-7 (MMP7) in regenerated endothelial cells. The reduced release of NO resulting from the endothelial dysfunction in regenerated areas creates a locus minoris resistentiae which favors the occurrence of vasospasm and thrombosis as well as the initiation of atherosclerosis. © Springer Science+Business Media, LLC 2010.

Gao Y.,Peking University | Vanhoutte P.M.,University of Hong Kong
Journal of Cardiovascular Pharmacology | Year: 2012

Nebivolol is a highly selective β 1-adrenoceptor blocker, which also stimulates endothelial nitric oxide synthase and scavenges reactive oxygen species (ROS). These characteristics endow nebivolol, compared with conventional β-blockers, with a favorable hemodynamic profile for the treatment of hypertension, chronic heart failure, and possibly other cardiovascular diseases. Nebivolol is a racemic mixture of d- and l-isomers. Its β 1-antagonistic properties reside primarily with d-nebivolol although both isomers are capable of increasing the release of NO from the endothelium after binding to β 2- or β 3- adrenergic receptors. The latter action results in vasodilatation and reduced vascular resistance. Nebivolol also scavenges ROS in a receptor-independent manner by direct interaction with free radicals. By scavenging ROS nebivolol not only reduces oxidant stress but also augments NO bioavailability. The endothelial nitric oxide synthase -stimulating and ROS scavenging effects of nebivolol act synergistically to provide cardiovascular protection in addition to its β 1-antagonistic action. © 2012 Lippincott Williams & Wilkins, Inc.