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Microcurvature landscapes induce neural stem cell polarity and enhance neural differentiation

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Bio-Design and Manufacturing 2023年第5期6卷 522-535页

作者： Ho-Yin Yuen wai-Sze yip Suet To Xin Zhao Department of Biomedical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina State Key Laboratory of Ultra-Precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina

Tissue curvature has long been recognized as an important anatomical parameter that affects intracellular behaviors,and there is emerging interest in applying cell-scale curvature as a designer property to drive cell fates for tissue engineering *** neural cells are known to undergo dramatic and terminal morphological changes during development and curvature-limiting behaviors have been demonstrated in neurite outgrowth studies,there are still crucial gaps in understanding neural cell behaviors,particularly in the context of a three-dimensional(3D)curvature landscape similar to an actual tissue engineering *** this study,we fabricated two substrates of microcurvature(curvature-substrates)that present a smooth and repeating landscape with focuses of either a concave or a convex *** these curvature-substrates,we studied the properties of morphological differentiation in N2a neuroblastoma *** contrast to other studies where two-dimensional(2D)curvature was demonstrated to limit neurite outgrowth,we found that both the concave and convex substrates acted as continuous and uniform mechanical protrusions that significantly enhanced neural polarity and differentiation with few morphological changes in the main cell *** enhanced differentiation was manifested in various properties,including increased neurite length,increased nuclear displacement,and upregulation of various neural *** demonstrating how the micron-scale curvature landscape induces neuronal polarity,we provide further insights into the design of biomaterials utilizing the influence of surface curvature in neural tissue engineering.

关键词： Curvature Neural differentiation Neurite outgrowth Mechanotransduction

Epstein-Barr virus infection and persistence in nasopharyngeal epithelial cells

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chinese Journal of Cancer 2014年第11期33卷 549-555页

作者： chi Man Tsang Wen Deng Yim Ling yip Mu-Sheng Zeng Kwok wai Lo Sai Wah Tsao Department of Anatomy Li Ka Shing Faculty of MedicineThe University of Hong Kong School of Nursing Li Ka Shing Faculty of MedicineThe University of Hong Kong State Key Laboratory of Oncology in South china Sun Yat-sen University Cancer Center Department of Anatomical and Cellular Pathology The Chinese University of Hong Kong

Epstein-Barr virus(EBV) infection is closely associated with undifferentiated nasopharyngeal carcinoma(NPC), strongly implicating a role for EBV in NPC pathogenesis; conversely, EBV infection is rarely detected in normal nasopharyngeal epithelial tissues. In general, EBV does not show a strong tropism for infecting human epithelial cells, and EBV infection in oropharyngeal epithelial cells is believed to be lytic in nature. To establish life-long infection in humans, EBV has evolved efficient strategies to infect B cells and hijack their cellular machinery for latent infection. Lytic EBV infection in oropharyngeal epithelial cells, though an infrequent event, is believed to be a major source of infectious EBV particles for salivary transmission. The biological events associated with nasopharyngeal epithelial cells are only beginning to be understood with the advancement of EBV infection methods and the availability of nasopharyngeal epithelial cell models for EBV infection studies. EBV infection in human epithelial cells is a highly inefficient process compared to that in B cells, which express the complement receptor type 2(CR2) to mediate EBV infection. Although receptor(s) on the epithelial cell surface for EBV infection remain(s) to be identified, EBV infection in epithelial cells could be achieved via the interaction of glycoproteins on the viral envelope with surface integrins on epithelial cells, which might trigger membrane fusion to internalize EBV in cells. Normal nasopharyngeal epithelial cells are not permissive for latent EBV infection, and EBV infection in normal nasopharyngeal epithelial cells usually results in growth arrest. However, genetic alterations in premalignant nasopharyngeal epithelial cells, including p16 deletion and cyclin D1 overexpression, could override the growth inhibitory effect of EBV infection to support stable and latent EBV infection in nasopharyngeal epithelial cells. The EBV episome in NPC is clonal in nature, suggesting that

关键词：病毒感染上皮细胞鼻咽癌持久性细胞周期蛋白D1 全国人民代表大会生长抑制作用 EB病毒

Laser induced fluorescence diagnostic for velocity distribution functions:applications,physics,methods and developments

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Plasma Science and Technology 2021年第5期23卷 75-95页

作者： chi-Shung yip Di JIANG Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People's Republic of China

With more than 30 years of development,laser-induced fluorescence(LIF)is becoming an increasingly common diagnostic to measure ion and neutral velocity distribution functions in different fields of studies in plasma science including Hall thrusters,linear devices,plasma processing,and basic plasma physical *** this paper,technical methods used in the LIF diagnostic,including modulation,collection optics,and wavelength calibration techniques are reviewed in detail.A few basic physical processes along with applications and future development associated with the LIF diagnostics are also reviewed.

关键词： plasma diagnostics laser induced fluorescence laser spectroscopy

Successful capture of red thrombus in acute inferior ST-elevation myocardial infarction

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Journal of Geriatric Cardiology 2018年第10期15卷 647-648页

作者： wai-Kin chi chi-Yuen CHAN Division of Cardiology Department of Medicine and TherapeuticsPrince of Wales Hospitalthe Chinese University of Hong KongHong KongChina

A 50-year-old gentleman with past medical history of hypertension presented with acute inferior ST-segment elevation myocardial infarction (STEMI).He complained severe chest pain despite onset time was more than *** p... 详细信息

关键词： Embolic protection device Successful capture Thrombus

Interplay of laser power and pore characteristics in selective laser melting of ZK60 magnesium alloys:A study based on in-situ monitoring and image analysis

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Journal of Magnesium and Alloys 2024年第4期12卷 1346-1366页

作者： Weijie Xie Hau-Chung Man chi-wai Chan Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Mechanical and Aerospace Engineering Queen’s UniversityBelfast BT95AHUK Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHong KongChina

This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)***-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 W and 60 *** morphological analysis was performed using Scanning-Electron Microscopy(SEM),demonstrating a critical correlation between laser power and pore *** laser power led to increased pore coverage,whereas a denser structure was observed at higher laser *** laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the *** increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore *** laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher *** interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.

关键词： Selective laser melting(SLM) Magnesium(Mg)alloys Biodegradable implants Porosity In-situ monitoring

Understanding the role of PIN1 in hepatocellular carcinoma

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World Journal of Gastroenterology 2016年第45期22卷 9921-9932页

作者： chi-wai Cheng Ka-wai Leong Eric Tse Department of Medicine The University of Hong Kong Queen Mary Hospital

PIN1 is a peptidyl-prolyl cis/trans isomerase that binds and catalyses isomerization of the specific motif comprising a phosphorylated serine or threonine residue preceding a proline(p Ser/Thr-Pro) in proteins. PIN1 can therefore induce conformational and functional changes of its interacting proteins that are regulated by proline-directed serine/threonine phosphorylation. Through this phosphorylation-dependent prolyl isomerization, PIN1 fine-tunes the functions of key phosphoproteins(e.g., cyclin D1, survivin, β-catenin and x-protein of hepatitis B virus) that are involved in the regulation of cell cycle progression, apoptosis, proliferation and oncogenic transformation. PIN1 has been found to be over-expressed in many cancers, including human hepatocellular carcinoma(HCC). It has been shown previously that overexpression of PIN1 contributes to the development of HCC invitro and in xenograft mouse model. In this review, we first discussed the aberrant transcription factor expression, miR NAs dysregulation, PIN1 gene promoter polymorphisms and phosphorylation of PIN1 as potential mechanisms underlying PIN1 overexpression in cancers. Furthermore, we also examined the role of PIN1 in HCC tumourigenesis by reviewing the interactions between PIN1 and various cellular and viral proteins that are involved in β-catenin, NOTCH, and PI3K/Akt/mT OR pathways, apoptosis, angiogenesis and epithelial-mesenchymal transition. Finally, the potential of PIN1 inhibitors as an anti-cancer therapy was explored and discussed.

关键词： Phosphorylation Hepatocellular carcinoma PIN1 Isomerization Hepatocarcinogenesis

Urocortin and cardiovascular protection

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Acta Pharmacologica Sinica 2004年第3期25卷 3-11页

作者： chi-wai LAU,Yau-chi CHAN,Suk-ying TSANG,Franky Leung CHAN The chinese University of Hong Kong Hong Kong china Department of Anatomy The chinese University of Hong Kong Hong Kong china Department of Anatomy The chinese University of Hong Kong Hong Kong china Department of Anatomy The chinese University of Hong Kong Hong Kong china Department of Anatomy

Urocortin and other hypothalamus corticotropin-releasing factor (CRF) polypeptides play biologically diverse roles in the stress, cardiovascular and inflammatory responses by acting on central and peripheral CRF receptors. Urocortin shows a significantly high sequence homology to CRF, and the concurrent expression of type-2 CRF (CRF2) receptors with urocortin in the heart suggests that urocortin may play a physiological role in the cardiac function. Urocortin is thought to be the endogenous agonist producing the cardiovascular actions previously attributed to CRF. This review highlights the current novel findings on the molecular and cellular mechanisms by which urocortin may exert its cardiovascular protective action.

关键词： urocortin corticotropin-releasing hormone vascular smooth muscle heart vasodilaion second messenger system protein kinases

LARGE EDDY SIMULATION OF VERTICAL JET IMPINGEMENT WITH A FREE SURFACE

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Journal of Hydrodynamics 2006年第2期18卷 148-155页

作者： CHEN Yong-ping LI chi-wai ZHANG Chang-kuang Departmentof Civil and Structural Engineering The Hongkong Polytechnic University Hongkong China College of Traffic and Ocean Engineering Hohai University Nanjing 210098 China

The flow characteristics of a 2D slot jet vertically impinging on free surfaces are numerically investigated by the Large Eddy Simulation （LES） with a dynamic Sub-Grid Scale （SGS） model. The σ-coordinate transformation is introduced to map the depth-variable physical domain to a depth-uniform computational domain. The split-operator scheme, which splits the solution procedure into advection, diffusion and pressure propagation steps, is employed to solve the instantaneous velocity and pressure field. A fully nonlinear Lagrange-Euler method is used to compute the free surface elevation. The numerical results show that the jet retains good self-similarity in the Zone of Eestablished Flow （ZEF）, while the turbulence of jet shifts gradually from isotropic to anisotropic in the Zone of Surface Impingement （ZSI）. When the jet approaches the free surface, the centerline velocity decreases rapidly and the flow is deflected by the free surface. Two symmetrical surface jets are formed in the Zone of Horizontal Jets （ZHJ）. An approximate Guassian distribution of super-elevation is also formed on the free surface. The computed results are in good agreement with the available experimental data.

关键词： Large Eddy Simulation (LES) 2D slot jet free surface

Virtual reality based multiple life skill training for intellectual disability:A multicenter randomized controlled trial

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Engineered Regeneration 2022年第2期3卷 121-130页

作者： James Chung-wai Cheung Ming Ni Andy Yiu-Chau Tam Tim Tin-Chun Chan Alyssa Ka-Yan Cheung Ocean Yu-Hong Tsang chi-Bun yip Wing-Kai Lam Duo wai-chi Wong Department of Biomedical Engineering Faculty of EngineeringThe Hong Kong Polytechnic UniversityHong Kong 999077China Research Institute for Smart Ageing The Hong Kong Polytechnic UniversityHong Kong 999077China Jockey Club Smart Ageing Hub Department of Biomedical EngineeringFaculty of EngineeringThe Hong Kong Polytechnic UniversityHong Kong 999077China Department of Orthopaedics Pudong New Area People’s Hospital Affiliated to Shanghai Jiaotong UniversityShanghai 201299China Social Service Department Yan Chai HospitalHong Kong 999077China C2 Innovations and Research Limited Hong Kong 999077China Department of Kinesiology Shenyang Sport UniversityShenyang 110102China Sports Information and External Affairs Centre Hong Kong Sports InstituteHong Kong 999077China

Life skill-based training is essential for intellectual disabled individuals to regain autonomy and social *** reality(VR)could deliver a nascent application that is more engaging and *** objective of this study was to evaluate the training effects of the VR-based multiple life skill training program on life skill perfor-mance,self-efficacy,memory,cognitive and behavioral functions via a multicenter randomized controlled trial.A total of 145 intellectual disabled participants were recruited for a randomized controlled trial with three in-tervention arms:VR(n=42);traditional(n=53);and control(n=50).The life skill tasks for the interventions included 1)grocery shopping,2)cooking,and 3)kitchen *** measures were performance scores for the three tasks,self-efficacy scale,digit span score,and Frontal Assessment Battery score,graded by blinded ***-after effects of each group were evaluated using separated Wilcoxon Signed-rank *** sig-nificantly improved cooking,cleaning performance,and memory span,while traditional training significantly improved shopping,cooking,and cleaning *** generalized estimating equation evaluated effects between groups adjusted for age,gender and intelligence quotient(IQ).VR had significantly larger improvement effects in cooking and cleaning than the control group and memory span compared to traditional training and controls *** appeared to be a significant confounder on the training *** work may consider developing artificial intelligence to customize programs depending on IQ level.

关键词： Mental retardation Intellectual development X-reality Immersive rehabilitation Metaverse