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Chinese Chemical Letters 2000年第8期11卷 667-670页

作者： Yu Fei SONG Pin YANG leung SHEH Institute of Molecular Science Shanxi UniversityTaiyuan 030006 Department of Chemistry Tunghai UniversityTaichungTaiwan 407-04

This paper reports an ongoing study of the use of short chain peptides as carriers of a potential antitumor agents: 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). Three new peptide-DMQ-MA conjugates: DMQ-MA-arg-arg-ome, DMQ-MA-lys(cbz)-arg-ome, DMQ-MA-lys(cbz)-arg-arg-ome were synthesized by coupling protected amino acids in solution and the next conjugation wa. achieved by reacting with pentafluorophenyl ester of DMQ-MA in DMF, and further study on their ability to inhibit human pulmonary adenocarcinoma cell line (PC-9 cells) and oral epidermoid carcinoma cell line (KB) are investigating.

关键词： 2 6-dimethoxyhydroquinone-3-mercaptoacetic acid

Low DHEAS levels are associated with depressive symptoms in elderly Chinese men： results from a large study

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Asian Journal of Andrology 2011年第6期13卷 898-902页

作者： Samuel YS Wong Jason C leung Timothy Kwok Claes Ohlsson Liesbeth Vandenput Ping C leung Jean Woo School of Public Health and Primary Care School of Public Health The Chinese University of Hong Kong Hong Kong China jockey Club Centre for Osteoporosis Care and Control The Chinese University of Hong Kong Hong Kong China Department of Medicine and Therapeutics The Chinese University of Hong Kong Hong Kong China Center for Bone Research Department of Internal Medicine University of Gothenburg Gothenburg SE-413 45 Sweden Division of Geriatrics Department of Medicine and Therapeutics The Chinese University of Hong Kong Hong Kong China

This study investigated the association between depressive symptoms in elderly Chinese men and the total testosterone, dehydroepiandrosterone （DHEA）, DHEA sulphate （DHEAS）, oestradiol and sex hormone-binding globulin （SHBG） levels, and the free androgen index. Cross-sectional data from 1147 community-dwelling elderly men, aged 65 and older, were used. Depressive symptoms were measured using the Chinese Geriatric Depression Scale （GDS）. Total testosterone, free testosterone, DHEA, DHEAS, total oestradiol, the free androgen index and SHBG levels were assessed. DHEA wa. significantly associated with GDS score, and there wa. a trend towa.ds DHEAS association, but this wa. not significant （p=-0. 110, P=0.015; p=-0.074, P=0.055）. However, no association wa. seen between depressive symptoms and total testosterone levels, free testosterone levels, oestradiol levels or SHBG levels. In terms of the presence of clinically relevant depressive symptoms, there were no statistically significant differences between patients in the lowest quartile of sex steroid hormone levels and those in other quartiles of sex steroid hormone levels. Similarly to Western studies, our study shows that DHEA and DHEAS levels are associated with depressive symptoms.

关键词： Chinese dehydroepiandrosterone depression elderly men testosterone

Mechanistic study of vacuum UV catalytic oxidation for toluene degradation over CeO_(2) nanorods

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Green Energy & Environment 2022年第3期7卷 533-544页

作者： Muyan Wu Yingguang Zhang Haibao Huang Dennis Y.C.leung Department of Mechanical Engineering The University of Hong KongPokfulam RoadHong KongChina School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou510275China

The present study specifically investigates vacuum ultraviolet (VUV) catalytic oxidation for toluene degradation over CeO_(2) *** effects of ultraviolet photocatalytic oxidation (UV-PCO) and ozone catalytic oxidation (OZCO) were manifested in the results of toluene removal and COx generation,while the combination of UV-PCO andOZCO (UV-OZCO) did not lead to improvement of *** the processes contribute to ozone decomposition,but no obvious synergetic effects of the different processes can be *** analysis results indicated that more toluene wa. oxidized into by-products,such as benzyl alcohol and benzaldehyde,by UV-OZCO rather than forming *** hydroxyl radical (·OH) and superoxide radical (·O_(2)^(-)) were found in all the processes of the VUV-PCO-OZCO system(combination of VUV photolysis,UV-PCO,OZCO and UV-OZCO processes).In the UV-OZCO process,the formation of hydroxyl radical wa. promoted,while that of superoxide radical wa. impeded,resulting in lower mineralization level of *** mechanistic study of toluene degradation over CeO_(2) nanorods in the VUV-PCO-OZCO system revealed that with the formation of·O_(2)^(-)and·OH,toluene is first oxidized to intermediates,followed by further ring–opening reaction and,finally,degradation into CO_(2) and H_(2)***_(2) nanorods function as both ozonation catalyst and photocatalyst,and the redox pair of Ce^(3+)and Ce^(4+)are interconvertible and can keep a balance.

关键词： toluene catalytic vacuum

Effects of building aspect ratio,diurnal heating scenario,and wind speed on reactive pollutant dispersion in urban street canyons

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Journal of Environmental Sciences 2012年第12期24卷 2091-2103页

作者： Nelson Y.O.Tong Dennis Y.C.leung Department of Mechanical Engineering The University of Hong Kong

A photochemistry coupled computational fluid dynamics （CFD） based numerical model has been developed to model the reactive pollutant dispersion within urban street canyons, particularly integrating the interrelationship among diurnal heating scenario （solar radiation affections in nighttime, daytime, and sun-rise/set）, wind speed, building aspect ratio （building-height-to-street-width）, and dispersion of reactive gases, specifically nitric oxide （NO）, nitrogen dioxide （NO2） and ozone （O3） such that a higher standard of air quality in metropolitan cities can be achieved. Validation has been done with both experimental and numerical results on flow and temperature fields in a street canyon with bottom heating, which justifies the accuracy of the current model. The model wa. applied to idealized street canyons of different aspect ratios from 0.5 to 8 with two different ambient wind speeds under different diurnal heating scenarios to estimate the influences of different aforementioned parameters on the chemical evolution of NO, NO2 and 03. Detailed analyses of vertical profiles of pollutant concentrations showed that different diurnal heating scenarios could substantially affect the reactive gases exchange between the street canyon and air aloft, followed by respective dispersion and reaction. Higher building aspect ratio and stronger ambient wind speed were revealed to be, in general, responsible for enhanced entrainment of 03 concentrations into the street canyons along windwa.d wa.ls under all diurnal heating scenarios. Comparatively, particular attention can be paid on the windwa.d wa.l heating and nighttime uniform surface heating scenarios.

关键词： photochemistry reactive pollutant dispersion building aspect ratio diurnal heating scenario wind speed urban streetcanyon

Structural, densitometric and biomechanical evaluations of Chinese patients with long-term bisphosphonate treatment

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Chinese Medical Journal 2013年第1期126卷 27-33页

作者： leung Kwok-sui TANG Ning James Griffith CHOY Tak-Kee HUNG Vivian Wing-Yin MOK Hoi-wa.SHI Lin leung Ping-Chung CHEUNG Wing-Hoi Department of Orthopaedics and Traumatology and Bone Quality and Health Center The Chinese University of Hong Kong Shatin Hong Kong SAR China Department of Imaging and Interventional Radiology The Chinese University of Hong Kong Shatin Hong Kong SAR China The Jockey Club Center for Osteoporosis Care and Control The Chinese University of Hong Kong Shatin Hong Kong SAR China Orthopaedic Research Laboratory of Translational MedicineResearch and Development Center Institute of Biomedical andHealth Engineering Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences China

Background The association of long-term bisphosphonate treatment for osteoporosis and related safety problems such as atypical fractures were not clearly defined. This study wa. to evaluate the structural, densitometric and biomechanical properties of the prolonged bisphosphonate-loaded bones. Methods Bone mineral density （BMD） at hip and femoral midshaft, bone cross-sectional area, moment of inertia of both femurs, bone formation and resorption biochemical markers were compared between 28 elderly with at least 4 years of bisphosphonate treatment from 2002 through 2006 and age-matched group of 37 elderly. Results The total hip BMD and t-score were found not different between two groups. However, bisphosphonate treated patients were found to have significantly lower bone mineral content in the femoral shaft （P 〈0.05）; morphological study showed lower cross-sectional area in subtrochanteric and mid-diaphyseal region and thus significantly lower moment of inertia （P 〈0.01）. High resolution-peripheral quantitative computed tomography showed significantly decreased trabeculardensity, bone volume ratio, trabecular number but increased trabecular spacing in tibia and distal radius. Finite element analysis further confirmed significantly lower stiffness and failure load in tibia. Biochemical studies also showed lower bone resorption and severely suppressed bone formation activity （P 〈0.001）. Conclusions The unchanged total hip BMD between two groups confirmed the beneficial effects of bisphosphonate on trabecular bone, thus preventing osteoporotic fractures at large in previous studies. However, the inferior structural, densitometric and biomechanical properties at cortical bones, especially femur midshaft, need a special attention to look into the association between long-term bisphosphonate intake and the occurrence of stress fractures. When patients taking bisphosphonate complain of proximal thigh pain or discomfort, plain X-ray film can be the first line screening. All

关键词： bisphosphonate bone mineral density moment of inertia HR-pQCT cortical bone

A review on the generation, determination and mitigation of Urban Heat Island

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Journal of Environmental Sciences 2008年第1期20卷 120-128页

作者： RIZwa. Ahmed Memon DENNIS Y.C. leung LIU Chunho Department of Mechanical Engineering the University of Hong Kong Hong Kong China.

Urban Heat Island （UHI） is considered as one of the major problems in the 21st century posed to human beings as a result of urbanization and industrialization of human civilization. The large amount of heat generated from urban structures, as they consume and re-radiate solar radiations, and from the anthropogenic heat sources are the main causes of UHI. The two heat sources increase the temperatures of an urban area as compared to its surroundings, which is known as Urban Heat Island Intensity （UHII）. The problem is even worse in cities or metropolises with large population and extensive economic activities. The estimated three billion people living in the urban areas in the world are directly exposed to the problem, which will be increased significantly in the near future. Due to the severity of the problem, vast research effort has been dedicated and a wide range of literature is available for the subject. The literature available in this area includes the latest research approaches, concepts, methodologies, latest investigation tools and mitigation measures. This study wa. carded out to review and summarize this research area through an investigation of the most important feature of UHI. It wa. concluded that the heat re-radiated by the urban structures plays the most important role which should be investigated in details to study urban heating especially the UHI. It wa. also concluded that the future research should be focused on design and planning parameters for reducing the effects of urban heat island and ultimately living in a better environment.

关键词： urban heat island (UHI) urbanization temperature rise mitigation

Food and Drug:A New Direction in the History of Medicine in China

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中医药文化(英文) 2023年第3期6卷 265-271页

作者： Angela Ki Che leung Chair Professor of History Joseph Needham-Philip Mao Professor in Chinese HistoryScienceand CivilizationHong Kong Institute for the Humanities and Social SciencesThe University of Hong KongHong Kong 518057China

1 Objects and their histories: unraveling the “black box”The history of object is a burgeoning field in contemporary historical studies. An object, like a “black box,” contains rich information that holds the secret code for knowledge construction. Object is a multifaceted being, consisting of aspects like technology, institution, human–object relationship, and human–nature interaction. Medicine and food inform sophisticated questions about society and ideology.

关键词： knowledge holds History

Comparative Genomic Study Reveals a Transition from TA Richness in Invertebrates to GC Richness in Vertebrates at CpG Flank-ing Sites:An Indication for Context-Dependent Mutagenicity of Methylated CpG Sites

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Genomics, Proteomics & Bioinformatics 2008年第3期6卷 144-154页

作者： Frederick C.C. leung School of Biological Sciences and Genome Research Centre The University of Hong Kong

Vertebrate genomes are characterized with CpG deficiency, particularly for GCpoor regions. The GC content-related CpG deficiency is probably caused by context-dependent deamination of methylated CpG sites. This hypothesis wa. examined in this study by comparing nucleotide frequencies at CpG flanking positions among invertebrate and vertebrate genomes. The finding is a transition of nucleotide preference of 5＇ T to 5＇ A at the invertebrate-vertebrate boundary, indicating that a large number of CpG sites with 5＇ Ts were depleted because of global DNA methylation developed in vertebrates. At genome level, we investigated CpG observed/expected （obs/exp） values in 500 bp fragments, and found that higher CpG obs/exp value is shown in GC-poor regions of invertebrate genomes （except sea urchin） but in GC-rich sequences of vertebrate genomes. We next compared GC content at CpG flanking positions with genomic average, showing that the GC content is lower than the average in invertebrate genomes, but higher than that in vertebrate genomes. These results indicate that although 5＇ T and 5＇ A are different in inducing deamination of methylated CpG sites, GC content is even more important in affecting the deamination rate. In all the tests, the results of sea urchin are similar to vertebrates perhaps due to its fractional DNA methylation. CpG deficiency is therefore suggested to be mainly a result of high mutation rates of methylated CpG sites in GC-poor regions.

关键词： CpG deficiency DNA methylation invertebrate genomes GC content

A Sub-Grid Structure Enhanced Discontinuous Galerkin Method for Multiscale Diffusion and Convection-Diffusion Problems

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Communications in Computational Physics 2013年第7期14卷 370-392页

作者： Eric T.Chung Wing Tat leung Department of Mathematics The Chinese University of Hong KongHong Kong

In this paper,we present an efficient computational methodology for diffusion and convection-diffusion problems in highly heterogeneous media as well as convection-dominated diffusion *** is well known that the numerical computation for these problems requires a significant amount of computermemory and ***,the solutions to these problems typically contain a coarse component,which is usually the quantity of interest and can be represented with a small number of degrees of *** are many methods that aim at the computation of the coarse component without resolving the full details of the *** proposed method falls into the framework of interior penalty discontinuous Galerkin method,which is proved to be an effective and accurate class of methods for numerical solutions of partial differential equations.A distinctive feature of our method is that the solution space contains two components,namely a coarse space that gives a polynomial approximation to the coarse component in the traditional wa. and a multiscale space which contains sub-grid structures of the solution and is essential to the computation of the coarse *** addition,stability of the method is *** numerical results indicate that the method can accurately capture the coarse behavior of the solution for problems in highly heterogeneous media as well as boundary and internal layers for convection-dominated problems.

关键词： Multiscale problem sub-grid capturing multiscale basis function boundary layer internal layer

Alcoholic ketoacidosis in two Chinese patients

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Chinese Medical Journal 2000年第11期113卷 91-93页

作者： Rossa WKChiu Hok-leung Tai and Ching-wa. Lam DepartmentofChemicalPathology TheChineseUniversityofHongKongPrinceofWalesHospitalHongKongChinaDepartmentofChemicalPathologyTheChineseUniversityofHongKongPrinceofWalesHospitalHongKongChina