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3D printing of hydroxyapatite/tricalcium phosphate scaffold with hierarchical porous structure for bone regeneration

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Bio-Design and Manufacturing 2020年第1期3卷 15-29页

作者： Xiangjia Li Yuan Yuan Luyang Liu yuen‑shan leung Yiyu Chen Yuxing Guo Yang Chai Yong Chen Epstein Department of Industrial and Systems Engineering University of Southern CaliforniaLos AngelesUSA Center for Craniofacial Molecular Biology University of Southern CaliforniaLos AngelesUSA Department of Chemical Engineering and Material Science University of Southern CaliforniaLos AngelesUSA Department of Aerospace and Mechanical Engineering University of Southern CaliforniaLos AngelesUSA Department of Oral and Maxillofacial Surgery Peking University School and Hospital of StomatologyBeijingChina

Three-dimensional(3D)-printed scaffolds have attracted considerable attention in recent years as they provide a suitable environment for bone cell tissue regeneration and can be customized in *** many other challenges,the material composition and geometric structure have major impacts on the performance of *** and tricalcium phosphate(HA/TCP),as the major constituents of natural bone and teeth,possess attractive biological properties and are widely used in bone scaffold *** fabrication methods have been investigated in attempts to achieve HA/TCP scaffolds with microporous structure enabling cell growth and nutrient ***,current 3D printing methods can only achieve the fabrication of HA/TCP scaffolds with certain range of microporous *** overcome this challenge,we developed a slurry-based microscale mask image projection stereolithography,allowing us to form a HA/TCP-based photocurable suspension with complex geometry including biomimetic features and hierarchical ***,the curing performance and physical properties of the HA/TCP suspension were investigated,and a circular movement process for the fabrication of highly viscous HA/TCP suspension was *** on these investigations,the scaffold composition was *** determined that a 30 wt%HA/TCP scaffold with biomimetic hierarchical structure exhibited superior mechanical properties and *** proliferation was investigated in vitro,and the surgery was conducted in a nude mouse in vivo model of long bone with cranial neural crest cells and bone marrow mesenchymal stem *** results showed our 3D-printed HA/TCP scaffold with biomimetic hierarchical structure is biocompatible and has sufficient mechanical strength for surgery.

关键词： 3D printing Slurry stereolithography Scaffold HA/TCP Hierarchical porosity

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A unified framework for isotropic meshing based on narrowband Euclidean distance transformation

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Computational Visual Media 2015年第3期1卷 239-251页

作者： yuen-shan leung Xiaoning Wang Ying He Yong-Jin Liu Charlie C.L.Wang School of Computer Engineering Nanyang Technological University Department of Computer Science and Technology Tsinghua University Department of Mechanical and Automation Engineering The Chinese University of Hong Kong

In this paper, we propose a simpleyet-effective method for isotropic meshing relying on Euclidean distance transformation based centroidal Voronoi tessellation(CVT). Our approach improves the performance and robustness of computing CVT on curved domains while simultaneously providing highquality output meshes. While conventional extrinsic methods compute CVTs in the entire volume bounded by the input model, we restrict the computation to a 3D shell of user-controlled thickness. Taking voxels which contain surface samples as sites, we compute the exact Euclidean distance transform on the GPU. Our algorithm is parallel and memory-efficient,and can construct the shell space for resolutions up to 20483 at interactive speed. The 3D centroidal Voronoi tessellation and restricted Voronoi diagrams are also computed efficiently on the GPU. Since the shell space can bridge holes and gaps smaller than a certain tolerance, and tolerate non-manifold edges and degenerate triangles, our algorithm can handle models with such defects, which typically cause conventional remeshing methods to fail. Our method can process implicit surfaces, polyhedral surfaces, and point clouds in a unified framework. Computational results show that our GPU-based isotropic meshing algorithm produces results comparable to state-ofthe-art techniques, but is significantly faster than conventional CPU-based implementations.

关键词： centroidal Voronoi tessellation(CVT) Euclidean distance transformation GPU isotropic meshing polygonal meshes point clouds implicit surfaces

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Fatty acids and algal lipids as precursors of chlorination by-products

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Journal of Environmental Sciences 2012年第11期24卷 1942-1946页

作者： Yan Liang yuen shan Lui Huachang Hong Croucher Institute for Environmental Sciences(CIES)and Department of Biology Hong Kong Baptist UniversityKowloon TongHong KongChina College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China Centre for Food Safety and Environmental Technology Guangzhou Institute of Advanced TechnologyChinese Academy of SciencesGuangzhou 511458China

Six common algal fatty acids （FAs） with different numbers of double bonds, lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal ceils were chlorinated to evaluate their potential in generating disinfection by-products （DBPs）. The result showed that the more double bonds in the FAs, the higher the amounts of chloroform and dichloroacetic acid （DCAA） produced, but such a pattern was not observed for trichloroacetic acid （TCAA）. Based on the previously reported composition of fatty acids in algal lipids, the DBP generation potentials of algal lipids were calculated. These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction, suggesting unknown lipophilic fraction（s） served as potent DBPs precursors. Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition, given quantified measured DBP production per unit algal lipid and proteins. The analysis showed that the observed DBP production was similar to that predicted （〈 35% difference）, suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform, DCAA and TCAA formation upon chlorinating algae.

关键词： algal lipid algal-derived organic materials chlorination by-products fatty acids

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Total conversion of centimeter-scale nickel foam into single atom electrocatalysts with highly selective CO_(2)electrocatalytic reduction in neutral electrolyte

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Nano Research 2023年第2期16卷 2003-2010页

作者： Qikui Fan Pengfei Gao shan Ren Yunteng Qu Chuncai Kong Jian Yang yuen Wu Ministry of Education Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Advanced Functional Materials and Mesoscopic PhysicsSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China Shenzhen Key Laboratory of Special Functional Materials Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Northwest Institute of Nuclear Technology Xi’an 710024China Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhou 215123China State Key Laboratory of Photoelectric Technology and Functional Materials International Collaborative Center on Photoelectric Technology and Nano Functional MaterialsInstitute of Photonics and Photon-TechnologyNorthwest UniversityXi’an 710069China Department of Chemistry iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)University of Science and Technology of ChinaHefei 230026China

To improve the atomic utilization of metals and reduce the cost of industrialization,the one-step total monoatomization of macroscopic bulk metals,as opposed to nanoscale metals,is *** this study,we used a thermal diffusion method to directly convert commercial centimeter-scale Ni foam to porous Ni single-atom-loaded carbon nanotubes(CNTs).As expected,owing to the coating of single-atom on porous,highly conductive CNT carriers,Ni single-atom electrocatalysts(Ni-SACs)exhibit extremely high activity and selectivity in CO_(2)electroreduction(CO_(2)RR),yielding a current density of>350 mA/cm^(2),a selectivity for CO of>91%under a flow cell configuration using a 1 M potassium chloride(KCl)*** on the superior activity of the Ni-SACs electrocatalyst,an integrated gas-phase electrochemical zero-gap reactor was introduced to generate a significant amount of CO current for potential practical *** overall current can be increased to 800 mA,while maintaining CO Faradaic efficiencies(FEs)at above 90%per unit *** findings and insights on the active site transformation mechanism for macroscopic bulk Ni foam conversion into single atoms can inform the design of highly active single-atom catalysts used in industrial CO_(2)RR systems.

关键词： Ni single atom electrocatalyst CO_(2)electroreduction to CO neutral electrolyte thermal diffusion

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Modulation of Neuroimmune Responses on Glia in the Central Nervous System： Implication in Therapeutic Intervention against Neuroinflammation

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Cellular & Molecular Immunology 2009年第5期6卷 317-326页

作者： Raymond Chuen-Chung Chang Kin Chiu yuen-shan Ho Kwok-Fai So Laboratory of Neurodegenerative Diseases Depamnent of Anatomy LKSFaculty of Medicine University of Hong Kong Pokfulam Hong KongSAR China Research Centre of Heart Brain Hormone and Healthy Aging LKSFaculty of Medicine University of Hong Kong Pokfulam Hong KongSAR China State Key Laboratory for Brain and Cognitive Sciences University of HongKong. Pokfulam Hong Kong SAR China Department of Anatomy LKS Faculty of Miedicine The University of Hong Kong Rm.

It has long been known that the brain is an immunologically privileged site in normal conditions. Although the cascade of immune responses can occur as long as there is a neuronal injury or a potent immune stimulation, how the brain keeps glial cells in a quiescent state is still unclear. Increasing efforts have been made by several laboratories to elucidate how repression oi~ immune responses is achieved in the neuronal environment. The suppression factors include neurotransmitters, neurohormones, neurotrophic factors, anti-inflammatory factors, and cell-cell contact via adhesion molecules or CD200 receptor. This review discusses how these factors affect the cascade of cerebral immune responses because no single factor listed above can fully account for the immune suppression. While several factors contribute to the suppression of immune responses, activation of glial cells and their production of pro-inflammatory factors do occur as long as there is a neuronal injury, suggesting that some neuronal components facilitate immune responses. This review also discusses which signals initiate or augment cerebral immune responses so that stimulatory signals override the suppressive signals. Increasing lines of evidence have demonstrated that immune responses in the brain are not always detrimental to neurons. Attempt to simply clear off inflammatory factors in the CNS may not be appropriate for neurons in neurological disorders. Appropriate control of immune cells in the CNS may be beneficial to neurons or even neuroregeneration. Therefore, understanding the mechanisms underlying immune suppression may help us to reshape pharmacological interventions against inflammation in many neurological disorders.

关键词： neural cell adhesion molecule neurotrophins potassium ions microglia neuroinflammation

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Syntheses,structures,and reactivity of ruthenium(Ⅱ) hydride complexes containing Klui's oxygen tripodal ligand

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Science China Chemistry 2010年第10期53卷 2139-2143页

作者： NG Ho-yuen LAI Chun-Sing WILLIAMS Ian D. leung Wa-Hung Department of Chemistry The Hong Kong University of Science and Technology

Treatment of Ru(CO)(Cl)(H)(PPh3)3 with NaLOEt (LOEt-= [CpCo{P(O)(OEt)2}3]-) afforded the hydride complex (PPh3)(CO)-LOEtRu(H) (1), which has been characterized by X-ray crystallography. Similarly, the tricyclohexylphosphine analogue, (PCy3)(CO)LOEtRu(H) (2), was synthesized from Ru(CO)Cl(H)(PCy3)2 and NaLOEt. Treatment of complex 1 with R'SO2N3 afforded the (arylsulfonyl)amido complexes LOEtRu(CO)(PPh3)(NHSO2R) (R = 2,4,6-i-Pr3C6H2 (3), 4-t-BuC6H4 (4)). The crystal structure of complex 3 has been determined. The Ru-N distance and Ru-N-S angle in 3 are 2.076(3) and 126.14(16)°, respectively. Reactions of complex 1 with acids have been studied.

关键词： ruthenium oxygen tripodal ligand hydride complex (arylsulfonyl)amido complex

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Economic analysis in product design——A case study of a TCM dietary supplement

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Chinese Journal of Chemical Engineering 2016年第1期24卷 202-214页

作者： yuen shan Cheng Ka Yip Fung Ka Ming Ng Christianto Wibowo Department of Chemical and Biomolecular Engineering The Hong Kong University of Science and Technology ClearWaterBay Technology Inc.

An approach for the economic analysis of chemical product design is proposed. It takes into account of customers' preference on product quality and economic considerations such as pricing, profit, market share, capital investment, and operating cost. The activities needed to support business decision making – identifying product quality, estimating product cost, calculating financial metrics, and performing make–buy analysis – are *** design of a Ganoderma lucidum dietary supplement, a traditional Chinese medicinal(TCM) product, is used to illustrate all the activities in this approach.

关键词： Product design Product conceptualization TCM dietary supplement Economic analysis Make–buy analysis

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Outcome of 1355 consecutive transabdominal chorionic villus samplings in 1351 patients

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中华医学杂志(英文版) 2005年第20期 5-11页

作者： LAU Tze Kin,leung Tak Yeung,FUNG Tak yuen,Daljit S SAHOTA,leung Tse Ngong Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital Chinese University of Hong Kong Shatin Hong Kong SAR China Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital Chinese University of Hong Kong Shatin Hong Kong SAR China Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital Chinese University of Hong Kong Shatin Hong Kong SAR China Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital Chinese University of Hong Kong Shatin Hong Kong SAR China Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital Chinese University of Hong Kong Shatin Hong Kong SAR China

Background The true risk of choronic villus sampling (C VS) is poorly defined. The objective of this study was to review the clinical o utcome of transabdominal CVS performed in a university teaching unit, with an em phasis on the complication rate. Methods A comprehensive audit database was maintained for 1351 pregnant women, including 17 sets of twin pregnancies, who had a CVS. Details a nd outcome of all CVSs made in the unit between May 1996 and May 2004 were revie wed. All CVSs were performed by one of 5 operators using the identical techniqu es. Results All procedures were performed transabdominally. A tota l of 1355 CVSs were performed because there were 4 dichorionic twin pregnancies which required 2 punctures. The mean gestation at CVS was (11.8±0.7) weeks, and 97.3% of the procedures were performed between 11 and 13 completed weeks. The majority (96.2%) required only 1 puncture to achieve correct needle placeme nt. The procedure failed to obtain an adequate sample in 4 subjects (0.30%). A total of 1351 chromosomal studies were requested and there was 1 case (0.07%) of culture failure. The results of chromosomal studies were available within 1 4 days in 36.7% of the cases and within 21 days in 94.0%. Overall, 77 chromos omal abnormalities (5.7%) and 5 cases of thalassemia major were detected. Preg nancy outcome was unknown in only 13 singleton subjects (0.96%). In the remain ing 1355 fetuses, there were 76 pregnancy terminations (5.56%), 10 fetal losses with obvious obstetric causes (0.73%), and 21 potentially procedure-relat ed fetal losses (1.54%). In the last group, the majority had one or more co-e xisting obstetric complications. The background fetal loss rate for pregnancies at similar gestational age in the unit was about 0.8%. Therefore, the procedu re-related fetal loss rate was estimated to be at the maximum of 0.74%. Conclusions In experienced hands, first trimester transabdomina l CVS is an accurate and safe invasive prenatal diagnostic procedur

关键词： chorionic villus sampling · postoperative complication · pregnancy outcome

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Percutaneous transgastric computed tomography-guided biopsy of the pancreas using large needles

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World Journal of Gastroenterology 2009年第47期15卷 5972-5975页

作者： Hsiuo-shan Tseng Chia-yuen Chen Wing P Chan Jen-Huey Chiang Department of Radiology Taipei Veterans General HospitalTaipei 112Taiwan China Department of Radiology School of MedicineNational Yang-Ming UniversityTaipei 112TaiwanChina Department of Radiology Taipei Medical University-Municipal Wan Fang HospitalTaipei 116TaiwanChina Department of Radiology School of MedicineTaipei Medical UniversityTaipei 116TaiwanChina

AIM:To assess the safety,yield and clinical utility of percutaneous transgastric computed tomography(CT)-guided biopsy of pancreatic tumor using large needles, in selected patients. METHODS:We reviewed 34 CT-guided biopsies in patients with pancreas mass,of whom 24(71%)had a direct path to the mass without passing through a major *** needle passed through the liver in one case(3%).Nine passes(26%)were made through the *** nine transgastric biopsies which used a coaxial technique(i.e.a 17-gauge coaxial introducer needle and an 18-gauge biopsy needle)were the basis of this *** and late follow-up CT images to detect complications were obtained. RESULTS:Tumor tissues were obtained in nine pancreatic biopsies,and histologic specimens for diagnosis were obtained in all *** patient,who had a rare sarco-matoid carcinoma,received a second *** patient had a complication of transient pneumoperitoneum but no subjective *** immediate imaging study and clinical follow-up detected neither hemorrhage nor *** delayed procedure-related complication was seen during the survival period of our ***:Pancreatic biopsy can be obtained by a transgastric route using a large needle as an alternative method,without complications of peritonitis or bleeding.

关键词： Biopsy Computed tomography Pancreas Stomach

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The Use of Technology to Enhance Taxpayer Service and Improve Tax Compliance——Experience of Hong Kong, China

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Belt and Road Initiative Tax Journal 2021年第1期2卷 47-51页

作者： leung To-shan Inland Revenue Department Hong Kong China

The Inland Revenue Department(IRD)is the authority which administers the tax law in the Hong Kong Special Administrative Region of the People’s Republic of *** article shares the IRD’s experience in applying digitalised tax administration to enhance taxpayer services and improve tax *** can be achieved through developing user-friendly digital platforms for filing and communication,the use of prepopulated tax returns,fillable PDF public forms and online systems for paying taxes,and providing accessible and easy-to-understand tax information on the Internet.

关键词： Inland Revenue Department Taxpayer service Electronic service Tax compliance Digitalised tax administration

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