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Performance of ground penetrating radar in root detection and its application in root diameter estimation under controlled conditions

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Science China Earth Sciences 2016年第1期59卷 145-155页

作者： yeung Shan Wing yan Wai Man HAU Chi Hang Billy Department of Civil Engineering The University of Hong Kong Kadoorie Institute The University of Hong Kong

A plant is stabilized by its root system. In congested urban cities such as Hong Kong, ground trenching is frequently seen due to the installation of utility lines along the roadside. Soil nailing, which involves soil coring in slopes, is a common solution to improve the slope stability. However, both activities inevitably pose a risk to the integrity of any root sys- tems present, and thus reduce the root anchorage. To prevent or minimize such damage, a careful design of the excava- tion/drilling location is of prime importance. Ground penetrating radar （GPR） provides a non-destructive method for locating roots by examining the contrast between the dielectric properties of the roots and the surrounding soil. To examine the perfor- mance of GPR and promote its use in Hong Kong, a test bed was prepared using local materials to create a controlled envi- ronment in which to conduct a series of systematic tests evaluating the performance of a 900 MHz GPR. The reflected radar- grams were subject to the influence of the following factors： size and depth of roots, horizontal distance between roots, and contrast between the root and soil water content. Correlations between root size and a number of waveform parameters were also explored. Limiting values for root size, root embedded depth, horizontal separation distance between roots, and water content contrast between root and soil were obtained. A significant correlation was found between the root diameter and time travel parameter T2 （p〈0.001, t=0.795）. Because GPR root detection is highly site-specific, this study provides a local refer- ence for GPR performance in the Hong Kong environment. The findings demonstrate that the 900 MHz GPR is applicable in Hong Kong for the detection of main roots.

关键词： GPR Radar profile Root detection Root water content Root size

Background-free three-dimensional selective imaging of anisotropic plasmonic nanoparticles

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Nano Research 2017年第4期10卷 1423-1433页

作者： Xiaodong Cheng Xuan Cao Bin Xiong yan He Edward S. yeung State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering College of Biology Hunan University Changsha 410082 China Department of Chemistry Tsinghua University Beijing 100084 China School of Medical Lab Science and Life Science Wenzhou Medical University Wenzhou 325035 China

There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit, especially in three-dimensional （3D） cellular environments. In this study, using a polarization-activated localization scheme based on the orientation-dependent properties of anisotropic plasmonic metal nanoparticles （MNPs）, ＂photoswitchable＂ imaging of single gold nanorods （AuNRs） was accomplished not only in two dimensions but also in three dimensions. Moreover, the Rayleigh scattering background arising from the congested subcellular structures was efficiently suppressed. Thus, we obtained the 3D distributions of both the position and the orientation of the AuNRs inside the cells and investigated their intemalization kinetics. To our knowledge, this is the first demonstration of the confocal-like 3D imaging of non-fluorescence nanoparticles with a high resolution and almost zero background. This technique is easy to implement and should greatly facilitate MNP studies and applications in biomedicine and biology.

关键词： anisotropic nanopartide localized surface plasmon resonance (LSPR) scattering imaging polarization microscopy orientation-dependent localization microscopy three-dimensional (3D) imaging

Three-dimensional stability of landslides based on local safety factor

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Journal of Mountain Science 2016年第9期13卷 1515-1526页

作者： yanG Tao Man-chu Ronald yeung yanG Bing LIU Yong-jiang yanG yan-xin School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China MOE Key Laboratory of Transportation Tunnel Engineering Chengdu 610031China Department of Civil Engineering California State Polytechnic UniversityPomonaCA 91768USA Transportation Research Institute of Chongqing Chongqing 400072China

Unlike the limit equilibrium method(LEM), with which only the global safety factor of the landslide can be calculated, a local safety factor(LSF) method is proposed to evaluate the stability of different sections of a landslide in this paper. Based on three-dimensional(3D) numerical simulation results, the local safety factor is defined as the ratio of the shear strength of the soil at an element on the slip zone to the shear stress parallel to the sliding direction at that element. The global safety factor of the landslide is defined as the weighted average of all local safety factors based on the area of the slip surface. Some example analyses show that the results computed by the LSF method agree well with those calculated by the General Limit Equilibrium(GLE) method in two-dimensional(2D) models and the distribution of the LSF in the 3D slip zone is consistent with that indicated by the observed deformation pattern of an actual landslide in China.

关键词： Landslide stability Local safety factor Stability analysis method Slip mechanism

Quality and readability of online information resources on insomnia

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Frontiers of Medicine 2017年第3期11卷 423-431页

作者： yan Ma Albert C. yang Ying Duan Ming Dong Albert S. yeung Division of Interdisciplinary Medicine and Biotechnology Department of Medicine Beth Israel Deaconess Medical Center Harvard Medical School Boston MA 02215 USA Sleep Medicine Center Airforee General Hospital Beijing 100142 China IBM Software Development Lab Littleton MA 01460 USA Depression Clinical and Research Program Massachusetts General Hospital Harvard Medical School Boston MA 02114 USA

The internet is a major source for health information. An increasing number of people, including patients with insomnia, search for remedies online; however, little is known about the quality of such information. This study aimed to evaluate the quality and readability of insomnia-related online information. Google was used as the search engine, and the top websites on insomnia that met the inclusion criteria were evaluated for quality and readability. The analyzed websites belonged to nonprofit, commercial, or academic organizations and institutions such as hospitals and universities. Insomnia-related websites typically included definitions （85%）, causes and risk factors （100%）, symptoms （95%）, and treatment options （90%）. Cognitive behavioral therapy for insomnia （CBT-I） was the most commonly recommended approach for insomnia treatment, and sleep drugs are frequently mentioned. The overall quality of the websites on insomnia is moderate, but all the content exceeded the recommended reading ease levels. Concerns that must be addressed to increase the quality and trustworthiness of online health information include sharing metadata, such as authorship, time of creation and last update, and conflicts of interest; providing evidence for reliability; and increasing the readability for a layman audience.

关键词： insomnia intemet readability information quality health literacy cognitive behavioral therapy treatment

Biocomposites:Their multifunctionality

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International Journal of Smart and Nano Materials 2010年第1期1卷 13-27页

作者： Kin-tak Lau Mei-po Ho Chi-ting Au-yeung Hoi-yan Cheung Centre of Excellence in Engineered Fibre Composites Faculty of Engineering and SurveyingUniversity of Southern QueenslandQueenslandAustralia Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

During the last decade,tissue engineering has shown a considerable promise in providing more viable alternatives to surgical procedures for harvested tissues,implants and *** to the fast development on nano-and biomaterial technologies,it is now possible for doctors to use patients’cells to repair orthopaedic defects such as focal articular cartilage *** order to support the three-dimensional tissue formation,scaffolds made by biocompatible and bioresorbable polymers and composite materials,for providing temporary support of damaged body and cell structures,have been developed *** ceramic and metallic materials have been widely accepted for the development of implants,their non-resorbability and necessity of second surgical operation(like for bone repair),which induce extra pain for the patients,limit their wide *** development of different types of biocomposites for biomedical engineering applications is *** biocomposites include(i)basic biomaterials;(ii)natural fiber-reinforced biocomposites and(iii)nanoparticle-reinforced *** multifunctionality is discussed in terms of the control of mechanical properties,biodegradability and bioresorbability.

关键词： multifunctional materials biocomposite

Risk of ischaemic and haemorrhagic stroke in Chinese undergoing percutaneous coronary intervention treated with potent P2Y12 inhibitor versus clopidogrel

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Stroke & Vascular Neurology 2022年第4期7卷 310-318,I0015-I0019页

作者： Andrew Kei-yan Ng Pauline yeung Ng April Ip Kui Kai Lau Chung-Wah Siu Cardiac Medical Unit Grantham HospitalHong KongHong Kong Department of Adult Intensive Care Queen Mary HospitalHong KongHong Kong Department of Medicine The University of Hong KongHong KongHong Kong The State Key Laboratory of Brain and Cognitive Sciences The University of Hong KongHong KongHong Kong

Background Stroke after acute coronary syndrome(ACS)can be *** is uncertain whether the risks of ischaemic stroke or intracranial haemorrhage(ICH)are associated with different choices of P2Y12 inhibitors(potent P2Y12 inhibitors such as ticagrelor and prasugrel vs clopidogrel).Even though East Asians are known to have different thrombotic and haemorrhagic profiles from Caucasians,data on Chinese patients are *** This was a retrospective cohort study conducting in Chinese patients with ACS who underwent first-ever percutaneous coronary intervention from 14 hospitals in Hong Kong between 2010 and *** primary efficacy endpoint was ischaemic *** secondary efficacy endpoint was a composite outcome of thrombotic events including all-cause mortality,non-fatal myocardial infarction and ischaemic *** primary safety endpoint was *** secondary safety endpoint was a composite of major bleeding *** After adjustment of baseline characteristics by 1:1 propensity score matching,a total of 6220 patients(3110 on each group)were *** with clopidogrel,potent P2Y12 inhibitors were associated with a lower risk of ischaemic stroke(HR 0.57;95%CI 0.37 to 0.87;p=0.008)and a lower risk of thrombotic events(HR 0.77;95%CI 0.66 to 0.90;p=0.001).Potent P2Y12 inhibitor was associated with similar risk of ICH(HR 0.65;95%CI 0.34 to 1.25,p=0.20)and major bleeding(HR 0.83;95%CI 0.68 to 1.01,p=0.069).Conclusions Potent P2Y12 inhibitors were associated with a lower adjusted risk of ischaemic stroke and thrombotic events,compared with *** risks of ICH and major bleeding were similar.

关键词： P2Y12 coronary haemorrhagic

High-speed 3D imaging based on structured illumination and electrically tunable lens

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Chinese Optics Letters 2017年第9期15卷 12-15页

作者： Dongping Wang Yunlong Meng Dihan Chen yeung yan Shih-Chi Chen Department of Mechanical and Automation Engineering The Chinese University of Hong KongShatinHong Kong SARChina Shenzhen Research Institute The Chinese University of Hong KongShenzhen 518057China

In this Letter, we present a high-speed volumetric imaging system based on structured illumination and an electrically tunable lens（ETL）, where the ETL performs fast axial scanning at hundreds of Hz. In the system,a digital micro-mirror device（DMD） is utilized to rapidly generate structured images at the focal plane in synchronization with the axial scanning unit. The scanning characteristics of the ETL are investigated theoretically and experimentally. Imaging experiments on pollen samples are performed to verify the optical cross-sectioning and fast axial scanning capabilities. The results show that our system can perform fast axial scanning and threedimensional（3D） imaging when paired with a high-speed camera, presenting an economic solution for advanced biological imaging applications.

关键词： ETL High-speed 3D imaging based on structured illumination and electrically tunable lens

Identification of the metabolites of biologically active xanthones isolated from Halenia elliptica *** by high performance liquid chromatography coupled to ion trap time-of-flight mass spectrometry

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Chinese Chemical Letters 2011年第7期22卷 839-842页

作者： Ru Feng Jian Gong Shi Xiao Wei Liu Chun Tao Che John H.K. yeung yan Wang Institute of Materia Medica Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100050 China Department of Ophthalmology Peking Union Medical College Hospital Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100730 China School of Chinese Medicine The Chinese University of Hong Kong Shatin NT Hong Kong SAR China Department of Pharmacology Faculty of Medicine The Chinese University of Hong Kong Shatin NZ Hong Kong SAR China

Metabolism study has been carried out on 1-hydroxy-2,3,5-trimethoxyxanthone （HM-1） and 1-hydroxy-2,3,4,7- tetramethoxyxanthone （HM-2）, which are two biologically active ingredients isolated from the Tibetan herb, Halenia elliptica D. Don., in rat liver microsomes in vitro. A method of high performance liquid chromatography coupled to ion trap time-of-flight mass spectrometry （LCMSn-ESI-IT-TOF） was applied to analyze metabolites of HM-1 and HM-2 on line, and five metabolites were identified containing 1,5-dihydroxy-2,3-dimethoxyxanthone （HM-5）, 1,7-dihydroxy-2,3,4-trimethoxyxanthone （HM-9）, 1,4, 7- trihydroxy-2,3-dimethoxyxanthone （HM-10）, 1,4-dihydroxy-2,3,7-trimethoxyxanthone （HM-11） and 1,2-dilaydroxy-3,4,7- trimethoxyxanthone （HM-12）. Among these metabolites, HM-9, HM-11, and HM-12 were isomers mutually. The results indicated that HM-1 and HM-2 occurred Phase I metabolic reaction of demethylation in rat microsomes in vitro.

关键词： Halenia elliptica Xanthone Biotransformation LCMSn-ESI-IT-TOF Metabolite identification

Unveiling Cellular Internalization Dynamics of Single Gold Nanorods by Tracking Their Orientational and Translational Motions

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CCS Chemistry 2022年第4期4卷 1295-1304页

作者： Dong Xu Yi Du Feng Ge yan He Edward S.yeung National Engineering Laboratory for Rice and By-Products Further Processing College of Food Science and EngineeringCentral South University of Forestry&TechnologyChangsha 410004 State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringCollege of BiologyHunan UniversityChangsha 410082 Department of Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology(Ministry of Education)Tsinghua UniversityBeijing 100084 Department of Chemistry Iowa State UniversityAmesIA 50011

Single nanoparticle tracking(SPT)is a unique and powerful tool to investigate the interaction between nanoparticles and cells,which is of considerable importance for nanotechnology applications in biomedical fields and in-depth understanding of biological ***,previous work typically focused on translations of single nanoparticles while they undergo both translational and rotational *** this study,we obtained both the translational and rotational dynamics of single gold nanorods during their cellular internalization process using dual-channel polarization *** particular,the azimuth and polar angles were integrated into a polar coordinate systemto obtain three general orientation distribution patterns,found to have a close relationship with the nanoparticle cellular internalization process and time-dependent ***,the patterns accompanied by trajectories,translational and rotational coefficients,the azimuth and polar angles,and other parameters provided a wealth of knowledge on the nanoparticle cellular internalization dynamics with unprecedented *** observed that the gold nanorods could initially assume a tip-first quick rotation state with partially restricted orientations,then change to a strongly confined near-vertical insertion state with slight angular fluctuations,and eventually transform into a random and fast rotation *** methodology opens up a new avenue for a detailed understanding of biological processes.

关键词： orientation distribution pattern nanoparticle cellular internalization orientational and translational motion single nanoparticle tracking