91 results on '"Leung C"'
Search Results
2. Effect of remote ischemic conditioning on the immune-inflammatory profile in patients with traumatic hemorrhagic shock in a randomized controlled trial.
- Author
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Leung, C. H., Rizoli, S. B., Trypcic, S., Rhind, S. G., Battista, A. P., Ailenberg, M., and Rotstein, O. D.
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HEMORRHAGIC shock , *ISCHEMIC conditioning , *REPERFUSION , *RANDOMIZED controlled trials , *TRAUMATIC shock (Pathology) , *PENETRATING wounds - Abstract
Resuscitation induced ischemia/reperfusion predisposes trauma patients to systemic inflammation and organ dysfunction. We investigated the effect of remote ischemic conditioning (RIC), a treatment shown to prevent ischemia/reperfusion injury in experimental models of hemorrhagic shock/resuscitation, on the systemic immune-inflammatory profile in trauma patients in a randomized trial. We conducted a prospective, single-centre, double-blind, randomized, controlled trial involving trauma patients sustaining blunt or penetrating trauma in hemorrhagic shock admitted to a Level 1 trauma centre. Patients were randomized to receive RIC (four cycles of 5-min pressure cuff inflation at 250 mmHg and deflation on the thigh) or a Sham intervention. The primary outcomes were neutrophil oxidative burst activity, cellular adhesion molecule expression, and plasma levels of myeloperoxidase, cytokines and chemokines in peripheral blood samples, drawn at admission (pre-intervention), 1 h, 3 h, and 24 h post-admission. Secondary outcomes included ventilator, ICU and hospital free days, incidence of nosocomial infections, 24 h and 28 day mortality. 50 eligible patients were randomized; of which 21 in the Sham group and 18 in the RIC group were included in the full analysis. No treatment effect was observed between Sham and RIC groups for neutrophil oxidative burst activity, adhesion molecule expression, and plasma levels of myeloperoxidase and cytokines. RIC prevented significant increases in Th2 chemokines TARC/CCL17 (P < 0.01) and MDC/CCL22 (P < 0.05) at 24 h post-intervention in comparison to the Sham group. Secondary clinical outcomes were not different between groups. No adverse events in relation to the RIC intervention were observed. Administration of RIC was safe and did not adversely affect clinical outcomes. While trauma itself modified several immunoregulatory markers, RIC failed to alter expression of the majority of markers. However, RIC may influence Th2 chemokine expression in the post resuscitation period. Further investigation into the immunomodulatory effects of RIC in traumatic injuries and their impact on clinical outcomes is warranted. ClinicalTrials.gov number: NCT02071290. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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3. Diffuse and concentrated nitrogen sewage pollution in island environments with differing treatment systems.
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Alldred, F. C., Gröcke, D. R., Leung, C. Y., Wright, L. P., and Banfield, N.
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SEWAGE ,FUCUS vesiculosus ,NITROGEN isotopes ,POLLUTION ,NITROGEN ,SEPTIC tanks - Abstract
Macroalgae is an under-utilised tool as a bioindicator of anthropogenic nitrogen loading to the coastal environment in the UK. This study compared two island systems—Jersey (Channel Islands) and St Mary's (Isles of Scilly) to assess how differing sewerage infrastructure affects nitrogen loading. A total of 831 macroalgae samples of Fucus vesiculosus and Ulva sp. were analysed for nitrogen isotopes (δ
15 N). Elevated δ15 N values were recorded for Jersey (> 9‰) in St Aubin's Bay—caused by the outflow of the Bellozanne Sewerage Treatment Works (STW). δ15 N isoplots maps indicate low diffusion of nitrogen out of St Aubin's Bay. St Mary's produced a varied δ15 N isoplot map in comparison. δ15 N was typically lower and is attributed to a smaller population and inefficient STW. Outflow of sewage/effluent at Morning Point, Hugh Town and Old Town produced elevated δ15 N values in comparison to the island average. St Mary's inefficient sewerage treatment and reliance on septic tanks/soakaways complicates δ15 N interpretation although it still indicates that nitrogen pollution is an island-wide issue. Future sewerage development and upgrades on islands are required to prevent similar effluent environmental issues as recorded in St Aubin's Bay. This study advocates the use of macroalgae as a bioindicator of nitrogen effluent in the marine environment. [ABSTRACT FROM AUTHOR]- Published
- 2023
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4. Polypharmacy Predicts Onset and Transition of Frailty, Malnutrition, and Adverse Outcomes in Peritoneal Dialysis Patients.
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Chan, Gordon C.-K., Ng, J. K.-C., Chow, K.-M., Cheng, P. M.-S., Law, M.-C., Leung, C.-B., Li, P. K.-T., and Szeto, C.-C.
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MORTALITY risk factors ,FRAIL elderly ,POLYPHARMACY ,RISK assessment ,TREATMENT effectiveness ,AGE factors in disease ,MALNUTRITION ,ACCIDENTAL falls ,HOSPITAL care ,DESCRIPTIVE statistics ,ADVERSE health care events ,LONGITUDINAL method ,BONE fractures ,DISEASE risk factors - Abstract
Background: Polypharmacy, frailty and malnutrition are known predictors of adverse outcomes in dialysis patients. Little has reported about their interaction and composite prognostic values. We aimed to describe the interaction between polypharmacy, frailty, nutrition, hospitalization, and survival in peritoneal dialysis patients. Methods: In this prospective cohort study, we recruited 573 peritoneal dialysis patients. Drug burden was measured by medication number and daily pill load. Frailty and nutrition were assessed by the validated Frailty Score (FQ) and Subjective Global Assessment (SGA) respectively. All patients were followed for two years. Primary outcome was all-cause mortality. Secondary outcomes were fall and fracture episodes, hospitalization, change in FQ and SGA. Results: At baseline, each patient took 7.5 ± 2.6 medications with 15.5 ± 8.5 tablets per day. Medication number, but not daily pill load predicted baseline FQ (p = 0.004) and SGA (p = 0.03). Over 2 years, there were 69 fall and 1,606 hospitalization episodes. In addition, 148 (25.8%) patients died, while FQ and SGA changed by 0.73 ± 4.23 and −0.07 ± 1.06 respectively in survivors. Medication number (hospitalization: p = 0.02, survival: p = 0.005), FQ (hospitalization: p < 0.001; survival: p = 0.01) predicted hospitalization and survival. Medication number also predicted fall episodes (p = 0.02) and frailty progression (p = 0.002). Daily pill load did not predict any of these outcomes. Conclusions: Drug burden is high in peritoneal dialysis patients, and it carries important prognostic implication. Medication number but not pill load significantly predicted onset and progression of frailty, malnutrition, fall, hospitalization, and mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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5. The Effectiveness of Data Augmentation of SEM Images on a Small Database Based on Deep-Learning Intelligence.
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Wong, C. H., Ng, S. M., Leung, C. W., and Zatsepin, A. F.
- Abstract
The software development in Nanoscience Foundries & Fine Analysis (NFFA) Europe Projects needs to train numerous scanning electron microscope (SEM) images. However, the price of preparing a large SEM dataset is always very high. To assist the NFFA Projects, we search for a suitable computational method to classify the SEM images on a small dataset. To prepare for identifying the composition of nanowire-fiber-mixtures images, we optimize the performance of image classification between nanowires, fibers, and tips due to their geometric similarities. The SEM images are analyzed by deep-learning techniques where the validation accuracies of 11 convolutional neural network (CNN) models are compared. By increasing the diversity of data such as reflection, translation, and scale factor approaches, the highest validation accuracy of recognizing nanowires, fibers, and tips is 97.1%. We proceed to classify the level of porosity in anodized aluminum oxide for the self-assisted nanowire growth where the validation accuracy can be optimized at 93%. Our software presents a path for scientists to count the percentage of fibers in any nanowire-fiber composite and design the porous substrate for embedding different sizes of nanowires automatically. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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6. Effects of a Mindfulness-Based Intervention on Distress, Weight Gain, and Glucose Control for Pregnant Low-Income Women: A Quasi-Experimental Trial Using the ORBIT Model.
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Epel, E., Laraia, B., Coleman-Phox, K., Leung, C., Vieten, C., Mellin, L., Kristeller, J. L., Thomas, M., Stotland, N., Bush, N., Lustig, R. H., Dallman, M., Hecht, F. M., and Adler, N.
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PREVENTION of mental depression ,PREVENTION of obesity ,PREVENTION of psychological stress ,PSYCHOLOGICAL stress ,FOOD habits ,GLUCOSE tolerance tests ,MATHEMATICAL models ,RESEARCH methodology ,POVERTY ,PREGNANT women ,WEIGHT gain in pregnancy ,WOMEN'S health ,THEORY ,TREATMENT effectiveness ,GLUCOSE intolerance ,PHYSICAL activity ,MINDFULNESS ,GLYCEMIC control ,PREGNANCY - Abstract
Background: Stress can lead to excessive weight gain. Mindfulness-based stress reduction that incorporates mindful eating shows promise for reducing stress, overeating, and improving glucose control. No interventions have tested mindfulness training with a focus on healthy eating and weight gain during pregnancy, a period of common excessive weight gain. Here, we test the effectiveness of such an intervention, the Mindful Moms Training (MMT), on perceived stress, eating behaviors, and gestational weight gain in a high-risk sample of low income women with overweight/obesity. Method: We conducted a quasi-experimental study assigning 115 pregnant women to MMT for 8 weeks and comparing them to 105 sociodemographically and weight equivalent pregnant women receiving treatment as usual. Our main outcomes included weight gain (primary outcome), perceived stress, and depression. Results: Women in MMT showed significant reductions in perceived stress (β = − 0.16) and depressive symptoms (β = − 0.21) compared to the treatment as usual (TAU) control group. Consistent with national norms, the majority of women (68%) gained excessive weight according to Institute of Medicine weight-gain categories, regardless of group. Slightly more women in the MMT group gained below the recommendation. Among secondary outcomes, women in MMT reported increased physical activity (β = 0.26) and had lower glucose post-oral glucose tolerance test (β = − 0.23), being 66% less likely to have impaired glucose tolerance, compared to the TAU group. Conclusion: A short-term intervention led to significant improvements in stress, and showed promise for preventing glucose intolerance. However, the majority of women gained excessive weight. A longer more intensive intervention may be needed for this high-risk population. Clinical Trials.gov #NCT01307683. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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7. Numerical modelling of hydro-mechanical behaviour of ground settlement due to rising water table in loess.
- Author
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Chen, Wenwu, Xu, Yanrong, Leung, C. F., and Yu, Jian
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LOESS ,FLUID mechanics ,COLLAPSIBLE soil ,WATER table ,NATURAL disasters - Abstract
The numerical simulation of collapsible settlement in loess soil subjected to rising ground water table is presented in this paper. A coupled hydro-mechanical model is proposed. Comparisons between the results of numerical simulations and those of oedometer and in situ water immersion field test in Lanzhou, northwest China, reveal good agreement, which validates the proposed model formulation. Factors that influence the ground settlement of loess including initial elevation of ground water table, rising water height and velocity are then evaluated. The results of the analyses reveal that the most critical situation of largest possible ground settlement due to ground water rising in loess involves initial water table elevation of 10 m and rising water velocity of 0.5 m/year. Two upper bound lines of predicted maximum possible ground settlement are proposed to facilitate a preliminary quick evaluation of ground settlement due to rising water under different water table scenarios in loess. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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8. Managing Intensive Care Supply-Demand Imbalance.
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Leung, C. C. H., Wong, W. T., and Gomersall, C. D.
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- 2016
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9. Forensic Geotechnics–Some Case Studies from Singapore.
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Leung, C. F.
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- 2016
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10. Performance of the new automated Abbott RealTi me MTB assay for rapid detection of Mycobacterium tuberculosis complex in respiratory specimens.
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Chen, J., She, K., Kwong, T.-C., Wong, O.-Y., Siu, G., Leung, C.-C., Chang, K.-C., Tam, C.-M., Ho, P.-L., Cheng, V., Yuen, K.-Y., and Yam, W.-C.
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MYCOBACTERIUM tuberculosis ,POLYMERASE chain reaction ,MICROBIOLOGICAL assay ,DIAGNOSTIC specimens ,MYCOBACTERIUM ,PATHOLOGICAL laboratories ,DIAGNOSIS - Abstract
The automated high-throughput Abbott RealTi me MTB real-time PCR assay has been recently launched for Mycobacterium tuberculosis complex (MTBC) clinical diagnosis. This study would like to evaluate its performance. We first compared its diagnostic performance with the Roche Cobas TaqMan MTB assay on 214 clinical respiratory specimens. Prospective analysis of a total 520 specimens was then performed to further evaluate the Abbott assay. The Abbott assay showed a lower limit of detection at 22.5 AFB/ml, which was more sensitive than the Cobas assay (167.5 AFB/ml). The two assays demonstrated a significant difference in diagnostic performance (McNemar's test; P = 0.0034), in which the Abbott assay presented significantly higher area under curve (AUC) than the Cobas assay (1.000 vs 0.880; P = 0.0002). The Abbott assay demonstrated extremely low PCR inhibition on clinical respiratory specimens. The automated Abbott assay required only very short manual handling time (0.5 h), which could help to improve the laboratory management. In the prospective analysis, the overall estimates for sensitivity and specificity of the Abbott assay were both 100 % among smear-positive specimens, whereas the smear-negative specimens were 96.7 and 96.1 %, respectively. No cross-reactivity with non-tuberculosis mycobacterial species was observed. The superiority in sensitivity of the Abbott assay for detecting MTBC in smear-negative specimens could further minimize the risk in MTBC false-negative detection. The new Abbott RealTi me MTB assay has good diagnostic performance which can be a useful diagnostic tool for rapid MTBC detection in clinical laboratories. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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11. Knowledge Extraction and Mining in Biomedical Research Using Rule Network Model.
- Author
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Chan, S. W., Leung, C. H. C., and Milani, A.
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- 2013
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12. Music Retrieval in Joint Emotion Space Using Audio Features and Emotional Tags.
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Deng, James J. and Leung, C. H. C.
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- 2013
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13. A New Dimension in Student Learning: Measuring Wait Times.
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Yuen, Joe C. H., Cheung, Albert C., Fung, K. L., Lai, Alvin C. K., Leung, C. M., and Lo, S. M.
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- 2013
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14. Risk-Based Railway Systems Design Adopted for the XRL.
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Leung, C. L. and Wong, S.
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- 2012
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15. Magnetoelectric Smart Current Sensors for Wireless Condition Monitoring of Train Traction Systems.
- Author
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Leung, C. M., Zhang, S. Y., Or, S. W., Ho, S. L., and Lee, K. Y.
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- 2012
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16. Development of Piezoelectric Transformer -Coupled Solid State Relay for Electrical Circuit Control in Railway Systems.
- Author
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Kuang, W., Or, S. W., Leung, C. M., and Ho, S. L.
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- 2012
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17. Music Emotion Retrieval Based on Acoustic Features.
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Deng, James Jie and Leung, C. H. C.
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- 2012
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18. Semantic Music Information Retrieval Using Collaborative Indexing and Filtering.
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Leung, C. H. C. and Chan, W. S.
- Abstract
With the rapid development of multimedia technology, digital music has become increasingly available and it constitutes a significant component of multimedia contents on the Internet. Since digital music can be represented in various forms, formats, and dimensions, searching such information is far more challenging than text-based search. While some basic forms of music retrieval is available on the Internet, these tend to be inflexible and have significant limitations. Currently, most of these music retrieval systems only rely on shallow music information (e.g., metadata, album title, lyrics, etc). Here, we present an approach for deep content-based music information retrieval, which focuses on high-level human perception, incorporating subtle nuances and emotional impression on the music (e.g., music styles, tempo, genre, mood, instrumental combinations etc.). We also provide a critical evaluation of the most common current Music Information Retrieval (MIR) approaches and propose an innovative adaptive method for music information search that overcomes the current limitations. The main focus of our approach is concerned with music discovery and recovery by collaborative semantic indexing and user relevance feedback analysis. Through successive usage of our indexing model, novel music content indexing can be built from deep user knowledge incrementally and collectively by accumulating users΄ judgment and intelligence. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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19. Collective Evolutionary Indexing of Multimedia Objects.
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Leung, C. H. C., Chan, W. S., and Liu, J.
- Abstract
The evolution of multimedia technology and the Internet boost the multimedia sharing and searching activities among social networks. The requirements of semantic multimedia retrieval goes far beyond those provided by the text-based search engines technology. Here, we present an collaborative approach that enables the semantic search of the multimedia objects by the collective discovery and meaningful indexing of their semantic concepts. Through the successive use of our model, semantic concepts can be discovered and incorporated by analyzing the users΄ search queries, relevance feedback and selection patterns. Eventually, through the growth and evolution of the index hierarchy, the semantic index can be dynamically constructed, validated, and naturally built-up towards the expectation of the social network. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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20. Numerical Study of Turbulent Flow in a Triangular Duct with Internal Ribbed Surfaces.
- Author
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Oberlack, Martin, Khujadze, George, Günther, Silke, Weller, Tanja, Frewer, Michael, Peinke, Joachim, Barth, Stephan, Luo, D. D., Leung, C. W., Chan, T. L., and Wong, W. O.
- Published
- 2007
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21. Transmission Electron Microscopy of FeBC Network Alloys: Part II.
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Yip, Y., Leung, C., Mok, S., Yip, K., and Kui, Hin
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STEEL ingots ,SPINODAL decomposition (Chemistry) ,TRANSMISSION electron microscopy ,SOLIDIFICATION ,MICROALLOYING ,CRYSTAL grain boundaries - Abstract
When undercooled deeply into its undercooling regime, a molten FeBC ingot undergoes spinodal decomposition, splitting into two interpenetrating subnetworks which are denoted by α-(liquid subnetwork) and β-(liquid subnetwork). Transmission electron microscopy results suggest that there are three constraints on crystal growth when the undercooled, decomposed molten ingot solidifies, which are (i) the solidification is due to the advancement of a bulk solid/liquid interface. It consists of a number of α-solid/liquid interfaces moving in the α-(liquid subnetwork) and a number of β-solid/liquid interfaces moving in the β-(liquid subnetwork); (ii) to overcome two long-range composition gradients of C and B atoms; and (iii) the two long-range composition gradients stabilize the bulk solid/liquid interface. The morphology of a solidified or network FeBC ingot is explained in terms of the obtained microscopic results. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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22. Scanning Electron Microscopy of FeBC Network Alloys: Part I.
- Author
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Chow, W., Leung, C., Yip, Y., Mok, S., and Kui, H.
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IRON alloys ,SCANNING electron microscopy ,MELTING ,METAL microstructure ,RANDOM variables ,CLASSIFICATION - Abstract
Molten FeBC melts can be cast into ingots of networklike microstructure. According to microstructural classification, a FeBC network specimen can be divided into three zones. Zone A is occupied by a random network, zone B by a uniformly aligned network, and zone C by a severely aligned network that exhibits network patterns. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
23. A comparison of engineered cementitious composites versus normal concrete in beam-column joints under reversed cyclic loading.
- Author
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Yuan, Fang, Pan, Jinlong, Xu, Zhun, and Leung, C.
- Abstract
Engineered cementitious composites (ECC) are a class of high-performance fiber reinforced cementitious composite with strain hardening and multiple cracking properties. For a reinforced concrete member, substitution of conventional concrete with ECC can significantly improve the deformation characteristics in terms of reinforced composite tensile or shear strength and energy dissipation ability. In this paper, a number of RC/ECC composite beam-column joints have been tested under reversed cyclic loading to study the effect of substitution of concrete with ECC in the joint zone on the seismic behaviors of composite members. The experimental parameters include shear reinforcement ratio in the joint zone, axial load level on the column and substitution of concrete with ECC or not. According to the test results, for the specimens without shear reinforcement in the joint zone, substitution of concrete with ECC in the joint zone cannot change the brittle shear failure in the joint zone, but can significantly increase the load capacity and ductility of the beam-column joint specimens, as well as the energy dissipation ability due to high ductility and shear strength of ECC material. For the specimens with insufficient or proper shear reinforcement ratio, substitution of concrete with ECC in the joint zone can lead to failure mode change from brittle shear failure in the joint zone to a more ductile failure mode, i.e. flexural failure at the base of the beam, with increased load capacity, ductility and energy dissipation ability. Increase of axial load on column and shear reinforcement in the joint zone have little effect on seismic behaviors of the members when they failed by flexural failure at the base of beam. In a word, the substitution of concrete with ECC in the joint zone was experimentally proved to be an effective method to increase the seismic resistance of beam-column joint specimens. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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24. Thermal tuning of surface plasmon resonance: Ag gratings on barium strontium titanate thin films.
- Author
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Xin, J., Hui, K., Wang, K., Chan, H., Ong, D., and Leung, C.
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SURFACE plasmon resonance ,REFRACTIVE index ,THIN films ,OPTICAL properties ,FERROELECTRIC crystals ,PULSED laser deposition ,MAGNESIUM oxide - Abstract
Surface plasmon tuning via thermally induced refractive index changes in ferroelectrics is investigated. Epitaxial (BaSr)TiO (BST) thin films were deposited on MgO (001) substrates by pulsed laser deposition. The refractive index of BST thin films measured by the prism-coupling technique was found to increase from 2.3932 (TE)/1.9945 (TM) at room temperature to 2.3949 (TE)/1.9965 (TM) at 66°C. Then 30-nm-Ag gratings with periodicity 750 nm and width 300 nm were fabricated on BST by soft ultraviolet nanoimprint lithography and subsequent lift-off process. The reflection spectra from 500 to 1000 nm with incident angle from 5° to 60° were measured at room temperature and 66°C, with a collimated and p-polarized light incident perpendicularly to the grating direction. Several modes were observed from the spectra. At 66°C, a red shift of a dip at about 850 nm by 2 nm was obtained at an incident angle of 15°. Calculations confirmed that the observed modes belong to the (−1), (2), (−2) and (3) surface plasmon modes from the Ag and BST interfaces and localized mode; the red shift by thermal tuning is also confirmed. The results indicate the feasibility of active modulation in surface plasmon resonance in solid-state structures. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
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25. Strontium titanate/silicon-based terahertz photonic crystal multilayer stack.
- Author
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Xin, J., Jim, K., Yang, J., Gong, X., Chen, L., Gao, F., Tsang, Y., Chan, H., and Leung, C.
- Subjects
PHOTONIC crystals ,STRONTIUM titanate ,REFRACTIVE index ,SILICON ,MATERIALS ,TERAHERTZ technology - Abstract
A one-dimensional photonic crystal working in the terahertz (THz) range was designed and implemented. To facilitate the design, the transmission properties of strontium titanate crystals were characterized by THz-time-domain spectroscopy. Relatively high refractive index (∼18.5) and transmission ratio (0.08) were observed between 0.2 to 1 THz. A stacked structure of (Si d/STO d)/Si d was then designed, with transmission spectra calculated by the transfer matrix method. The effects of the filling ratio ( d/( d+ d)), periodicity ( d+ d) and the number of repeats N on the transmission of PC were investigated. The effect of introducing a defect layer was also studied. Based on these, Si/STO multilayers with STO defect thickness of 125 μm and 200 μm were measured. The shift of the defect mode was observed and compared with the calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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26. Analytical and numerical modelling of FRP debonding from concrete substrate under pure shearing.
- Author
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Pan, Jinlong, Xu, Zhun, Leung, C., and Li, Zongjin
- Abstract
External bonding of fiber reinforced polymer (FRP) composites on the concrete structures has been proved to be an effective and efficient way to strengthen concrete structures. For a FRP strengthened concrete beam, it is usually observed that the failure occurs in the concrete and a thin layer of concrete is attached on the surface of the debonded FRP plate. To study the debond behavior between concrete and FRP composites, an analytical model based on the three-parameter model is developed to study the debonding behavior for the FRP-to-concrete joint under pure shearing. Then, nonlinear FEM analysis is conducted to verify the proposed analytical model. The FEM results shows good agreement with the results from the model. Finally, with the analytical model, sensitivity analyses are performed to study the effect of the interfacial parameters or the geometric parameters on the debonding behavior. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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27. Modelling the IDV Emissions of the BL Lac Objects with a Langevin Type Stochastic Differential Equation.
- Author
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Leung, C., Wei, J., Harko, T., and Kovacs, Z.
- Subjects
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BL Lacertae objects , *STOCHASTIC differential equations , *LANGEVIN equations , *ACCRETION (Astrophysics) , *DISKS (Astrophysics) , *BLACK holes , *OSCILLATIONS - Abstract
In this paper, we introduce a simplified model for explaining the observations of optical intra-day variability (IDV) of the BL Lac Objects. We assume that the source of the IDV are the stochastic oscillations of an accretion disk around a supermassive black hole. The stochastic fluctuations on the vertical direction of the accretion disk are described by using a Langevin type equation with a damping term and a random, white noise type force. Furthermore, preliminary numerical simulation results are presented, which are based on the numerical analysis of the Langevin stochastic differential equation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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28. Anterior chamber angle imaging with optical coherence tomography.
- Author
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Leung, C. K.-S. and Weinreb, R. N.
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OPTICAL coherence tomography , *IMAGING systems , *SCLERA , *PATHOLOGICAL physiology , *VISUAL perception - Abstract
The technology of optical coherence tomography (OCT) has evolved rapidly from time-domain to spectral-domain and swept-source OCT over the recent years. OCT has become an important tool for assessment of the anterior chamber angle and detection of angle closure. Improvement in image resolution and scan speed of OCT has facilitated a more detailed and comprehensive analysis of the anterior chamber angle. It is now possible to examine Schwalbe's line and Schlemm's canal along with the scleral spur. High-speed imaging allows evaluation of the angle in 360°. With three-dimensional reconstruction, visualization of the iris profiles and the angle configurations is enhanced. This article summarizes the development and application of OCT for anterior chamber angle measurement, detection of angle closure, and investigation of the pathophysiology of primary angle closure. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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29. Assessment of rates of structural change in glaucoma using imaging technologies.
- Author
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Mansouri, K., Leite, M. T., Medeiros, F. A., Leung, C. K., and Weinreb, R. N.
- Subjects
GLAUCOMA ,IMAGING systems ,SCANNING laser ophthalmoscopy ,OPTIC disc ,OPTIC nerve ,PATIENTS - Abstract
PurposeTo review the ability of current imaging technologies to provide estimates of rates of structural change in glaucoma patients.Patients and methodsReview of literature.ResultsImaging technologies, such as confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT), provide quantifiable and reproducible measurements of the optic disc and parapapillary retinal nerve fibre layer (RNFL). Rates of change as quantified by the rim area (RA) (for CSLO) and RNFL thickness (for SLP and OCT) are related to glaucoma progression as detected by conventional methods (eg, visual fields and optic disc photography). Evidence shows that rates of RNFL and RA loss are significantly faster in progressing compared with non-progressing glaucoma patients.ConclusionMeasurements of rates of optic disc and RNFL change are becoming increasingly precise and individualized. Currently available imaging technologies have the ability to detect and quantify progression in glaucoma, and their measurements may be suitable end points in glaucoma clinical trials. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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30. Sugary beverage and food consumption, and leukocyte telomere length maintenance in pregnant women.
- Author
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Leung, C W, Laraia, B A, Coleman-Phox, K, Bush, N R, Lin, J, Blackburn, E H, Adler, N E, and Epel, E S
- Abstract
Leukocyte telomere length (LTL) has been inversely associated with sugar-sweetened beverage (SSB) consumption in cross-sectional studies, but no studies have examined whether dietary intake influences LTL over time. This study examined longitudinal associations between sugary foods and beverages and LTL. Participants were 65 overweight and obese pregnant women, aged 18-45 years, from a mindfulness intervention study conducted from early pregnancy (⩽16 weeks gestation) and followed through 9 months postpartum. During pregnancy and postpartum, dietary intake was measured with 24-h diet recalls, and LTL was assessed using quantitative PCR. Adjusting for sociodemographic and health characteristics, decreased SSB consumption from baseline to 9 months postpartum was associated with greater concurrent LTL lengthening (β=-0.102, 95% confidence interval (CI) -0.192, -0.013). No associations between sugary foods and LTL were found in either period. The finding that reduced SSB consumption is associated with increased LTL warrants investigation in large cohort studies. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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31. Magnetoelectric effect in laminates of polymer-based pseudo-1–3 (Tb0.3Dy0.7)0.5Pr0.5Fe1.55 composite and 0.3Pb(Mg1/3Nb2/3)O3–0.7PbTiO3 single crystal
- Author
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Wang, Y. J., Leung, C. M., Or, S. W., Zhao, X. Y., Luo, H. S., Lv, X. K., and Zhang, Z. D.
- Subjects
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SPINTRONICS , *MAGNETIC fields , *FIELD theory (Physics) , *DIGITAL communications , *POLYMERS - Abstract
We report an extrinsic magnetoelectric effect in composite laminates made by sandwiching one thickness-polarized 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) piezoelectric single crystal plate between two length-magnetized, polymer-based pseudo-1–3 (Tb0.3Dy0.7)0.5Pr0.5Fe1.55 magnetostrictive composite plates. The laminates exhibit large magnetoelectric voltage coefficients ( α V) of ∼0.17 V/Oe with a flat response for frequencies in excess of 40 kHz and of ∼2.97 V/Oe at the natural resonance frequency of ∼65 kHz. The distinct advantages of the laminates include high magnetic field sensitivity, low Joule heating loss, wide operating bandwidth, and low cost. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
32. Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study.
- Author
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Cheung, C. Y. L., Yiu, C. K. F., Weinreb, R. N., Lin, D., Li, H., Yung, A. Y., Pang, C. P., Lam, D. S. C., and Leung, C. K. S.
- Subjects
OPTICAL coherence tomography ,COHERENCE (Optics) ,OPTIC nerve ,REFRACTIVE errors ,VISION disorders ,CLINICAL trials - Abstract
ObjectiveTo study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models.MethodsForty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1 to 2.5 mm). The RNFL profile in each eye was constructed with a mathematical model using a smoothing spline approximation. Scan circle (diameter 3.4 mm) RNFL measurements (total average, superior, nasal, inferior, and temporal RNFL thicknesses) obtained from eight directions (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, and superotemporal) displaced at different distances (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 mm) from the disc centre were then computed by a computer program and compared to the ‘reference standard’ where the scan circle is centred at the optic disc. RNFL measurement error was calculated as the absolute of (RNFL thickness
(displaced) – RNFL thickness(reference standard) ).ResultsThe respective mean average, superior, nasal, inferior, and temporal RNFL measurement errors were 2.3±2.0, 4.9±4.5, 4.1±3.8, 6.2±7.6, and 3.8±3.5 μm upon 0.1 mm scan circle displacement, and 12.1±11.4, 27.8±18.4, 21.7±18.6, 34.8±22.9, and 15.2±10.7 μm upon 0.7 mm scan circle displacement. Significant differences of average and quadrant RNFL thicknesses were evident between centred and displaced scan circle measurements (all with P<0.001). RNFL measurement error increased in a monotonic fashion with increasing distance away from the disc and the change was direction-dependent.ConclusionsRNFL measurement error varies with the direction and distance of scan displacement. The superior and the inferior RNFL measurements are most vulnerable to scan displacement errors, whereas the average RNFL thickness is the least susceptible. Obtaining a well-centred scan is essential for reliable RNFL measurement in OCT.Eye (2009) 23, 1436–1441; doi:10.1038/eye.2008.258; published online 19 September 2008 [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
33. Peak plasma rifampicin level in tuberculosis patients with slow culture conversion.
- Author
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Chang, K.-C., Leung, C.-C., Yew, W.-W., Kam, K.-M., Yip, C.-W., Ma, C.-H., Tam, C.-M., Leung, E., Law, W.-S., and Leung, W.-M.
- Subjects
- *
RIFAMPIN , *THERAPEUTICS , *TUBERCULOSIS , *LUNG diseases , *CLINICAL trials , *MEDICAL research , *PATIENTS , *HIV infections , *DRUG resistance in microorganisms - Abstract
The clinical utility of therapeutic drug monitoring in tuberculosis has not been adequately evaluated by controlled clinical trials. To examine the relationship between slow culture conversion and peak plasma rifampicin level (Cmax-rfm) in a case-control study, patients with persistence of positive sputum smear despite at least 8 weeks of directly observed treatment with standard pyrazinamide-containing regimens were enrolled prospectively in government chest clinics from 16 December 2005 to 15 November 2006. Patients with multidrug-resistant tuberculosis, human immunodeficiency virus infection, or poor treatment adherence were excluded. Cases referred to patients with persistence of positive culture whereas controls had negative culture despite positive smear. Blood was checked at 2 and 4 hours post-dosing to capture Cmax-rfm. A cohort of 88 patients was identified. After excluding 16 patients, there were 36 controls and 36 cases. None had symptoms of malabsorption. Cmax-rfm was below 6 mg/l among 47% of controls and 44% of cases. Univariate and multiple logistic regression analyses showed no significant association between slow culture conversion and Cmax-rfm after logarithmic transformation. Thus, there is probably no association between Cmax-rfm and slow culture conversion. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
34. In vivo measurements of macular and nerve fibre layer thickness in retinal arterial occlusion.
- Author
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Leung, C. K. S., Tham, C. C. Y., Mohammed, S., Li, E. Y. M., Leung, K. S., Chan, W.-M., and Lam, D. S. C.
- Subjects
- *
ARTERIAL occlusions , *ARTERIAL diseases , *NERVE fibers , *OPTICAL coherence tomography , *VISUAL fields , *EYE - Abstract
AimTo investigate the structure–function relationship in patients with retinal arterial occlusion by measuring the macular and the peripapillary retinal nerve fibre layer (RNFL) thickness and the visual sensitivity.MethodsThis is an observational case series with three patients with central retinal arterial occlusion (CRAO) and two patients with branch retinal arterial occlusion (BRAO). The macular/peripapillary RNFL thickness and the visual field were measured with Stratus optical coherence tomography (OCT) and Humphrey visual field analyzer, respectively, at least 1 year after the diagnosis of CRAO or BRAO.ResultsThe macular thickness, in particular the inner retinal layer, and the peripapillary RNFL thickness were reduced in patients with retinal arterial occlusion. The decrease in the macular and the peripapillary RNFL thickness corresponded to the sites of retinal arterial occlusion with diffuse and segmental thinning found in CRAO and BRAO, respectively. Visual field defects were found in the corresponding locations of macular and RNFL thinning, and closely correlated with the degree of the structural damage.ConclusionsStructural damages in terms of reduction in the macular and peripapillary RNFL thickness were evident in patients with retinal arterial occlusion. A close structure–function correlation was found and a worse functional outcome is associated with a more extensive thinning of the macula and RNFL. OCT measurements of the macular/peripapillary RNFL thickness provide useful indicators to reflect the severity of the disease in retinal arterial occlusion and serve as a new paradigm to study and monitor the disease longitudinally.Eye (2007) 21, 1464–1468; doi:10.1038/sj.eye.6702457; published online 2 June 2006 [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
35. MTB, the murine homolog of condensin II subunit CAP-G2, represses transcription and promotes erythroid cell differentiation.
- Author
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Xu, Y, Leung, C G, Lee, D C, Kennedy, B K, and Crispino, J D
- Subjects
- *
MITOSIS , *CHROMOSOMES , *GENOMICS , *ERYTHROPOIESIS , *TRANSCRIPTION factors - Abstract
Chromosome condensation is essential for proper segregation of duplicated sister chromatids in mitosis. Mammalian erythroid maturation is also associated with gradual nuclear condensation. However, few proteins that are directly involved in chromosome condensation during erythropoiesis have been identified. In this report, we show that MTB (more than blood), which was initially isolated in a yeast two-hybrid screen for proteins that interact with the basic helix-loop-helix (bHLH) protein stem cell leukemia (SCL), and later identified as the murine homolog of the condensin II subunit CAP-G2, participates in erythroid cell development. MTB interacts with SCL and another hematopoietic bHLH protein, E12, and is recruited to the nucleus by SCL and E12. In addition, MTB can repress SCL/E12-mediated transcriptional activation. Consistent with the model that MTB may function together with SCL/E12 heterodimer during erythroid cell development, MTB is highly expressed in the erythroid lineage and is upregulated upon erythroid differentiation. Moreover, overexpression of MTB promotes the terminal differentiation of the murine erythroleukemia erythroid cell line. Together, these findings demonstrate that the condensin II subunit MTB/mCAP-G2 plays a novel function during erythropoiesis and suggest that key hematopoietic transcription factors such as SCL and E12 may regulate the terminal differentiation of hematopoietic cells through the interaction with condensin complexes. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
36. Polychlorinated Biphenyls and Organochlorine Pesticides in Human Adipose Tissue and Breast Milk Collected in Hong Kong.
- Author
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Poon, B. H. T., Leung, C. K. M., Wong, C. K. C., and Wong, M. H.
- Subjects
PHYSIOLOGICAL effects of chemicals ,POLYCHLORINATED biphenyls ,ORGANOCHLORINE compounds ,PESTICIDES ,BREAST milk ,POLLUTANTS - Abstract
Contamination from persistent organic pollutants is a pervasive global problem that urgently demands global concern and action. In the present study, concentrations of organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) were determined in 37 samples of female adipose tissue collected in Hong Kong hospitals. Among the pollutants analyzed, DDTs (2.79 ng/g fat), HCHs (0.72 ng/g fat), and PCBs (0.19 ng/g fat) were prominent compounds in most of the adipose tissue. p,p′-DDE and hexachlorinated biphenyls were found in all samples, whereas heptachlor epoxide and dieldrin were found only in some samples. An estimation of toxic equivalency concentration (TEQ) due to dioxin-like coplanar PCBs was also performed. The estimated TEQ
PCBs was 2.01 pg/g fat. This study also compared our previous results obtained from the milk samples of the same donors. Significant correlations are obtained for DDTs and HCHs between milk and adipose tissue. Detailed review of available information concerning OC pesticides and PCBs in different ecological compartments indicated that bioconcentration and biomagnification of these contaminants are common phenomena of the Pearl River Delta region, which has undergone rapid socioeconomic change in the past 20 years. It is suggested to establish a regional organization in order to coordinate the monitoring of persistent organic pollutants in the region. [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
37. Inhibition of histone deacetylase 2 increases apoptosis and p21Cip1/WAF1 expression, independent of histone deacetylase 1.
- Author
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Huang, B. H., Laban, M., Leung, C. H.-W., Lee, L., Lee, C. K., Salto-Tellez, M., Raju, G. C., and Hooi, S. C.
- Subjects
HISTONE deacetylase ,AMIDASES ,APOPTOSIS ,GENE expression ,CELL death ,CELL differentiation - Abstract
Histone deacetylases (HDACs) 1 and 2 share a high degree of homology and coexist within the same protein complexes. Despite their close association, each possesses unique functions. We show that the upregulation of HDAC2 in colorectal cancer occurred early at the polyp stage, was more robust and occurred more frequently than HDAC1. Similarly, while the expression of HDACs1 and 2 were increased in cervical dysplasia and invasive carcinoma, HDAC2 expression showed a clear demarcation of high-intensity staining at the transition region of dysplasia compared to HDAC1. Upon HDAC2 knockdown, cells displayed an increased number of cellular extensions reminiscent of cell differentiation. There was also an increase in apoptosis, associated with increased p21
Cip1/WAF1 expression that was independent of p53. These results suggest that HDACs, especially HDAC2, are important enzymes involved in the early events of carcinogenesis, making them candidate markers for tumor progression and targets for cancer therapy.Cell Death and Differentiation (2005) 12, 395-404. doi:10.1038/sj.cdd.4401567 Published online 21 January 2005 [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
38. STIFFNESS MEASUREMENT OF THE EXTERNAL POLYMERIC COATING ON AN OPTICAL FIBER.
- Author
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Olson, N. G., Leung, C., and Wang, X.
- Subjects
- *
SURFACE coatings , *OPTICAL fibers , *COATING processes , *TESTING , *STRAINS & stresses (Mechanics) - Abstract
Summarizes results on the measurement of fiber coating stiffness with the nano-indentation technique. Explanation of the principle of the nano indenter; Sample preparation for the nano-indentation test; Two types of optical fiber that were tested; Influence of the change in Poisson's Ratio on the calculated value of modulus; Significance of optical fiber sensors to structural quantities such as strain and crack opening.
- Published
- 2002
- Full Text
- View/download PDF
39. Heat transfer characteristics of premixed butane/air flame jet impinging on an inclined flat surface.
- Author
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Dong, L. L., Leung, C. W., and Cheung, C. S.
- Abstract
A series of experiments were carried out to determine the heat transfer characteristics of a round, premixed butane/air flame jet impinging upwards on an inclined flat plate, at different angles of incidence. The flame was fixed with an equivalence ratio of 1.0, a Reynolds number of 2500 and a plate-to-nozzle distance of 5 d, while the inclination angles chosen for investigation were 57°, 67°, 80° and 90°. It was found that the location of the maximum heat flux point would be shifted away from the geometrical impingement point by reducing the angle of incidence. Decreasing the angle of incidence also enhanced the maximum local heat flux, while reduced the average heat transfer. The present study presented the effect of angle of incidence on the heat transfer characteristics of an impinging butane/air flame jet, which had been rarely reported in previous similar studies. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
40. Startup analysis of oil-fired furnace – the smoothing Monte Carlo model approach.
- Author
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Liu, M. S., Choi, C. K., and Leung, C. W.
- Abstract
A multi-dimensional mathematical thermal model of the oil-fired furnace has been developed. Radiation calculation of this model is based on the Hottel's zone method incorporating with the statistical Monte Carlo method to determine the total exchange areas. The whole furnace is divided into 4 gaseous zones and 18 surface zones. The Monte Carlo method integrated with the least square smoothing technique considering both conservation and reciprocity is used to evaluate the total exchange areas, i.e. surface–surface, surface–gas, gas–gas and gas–surface, directly for both the absorbing and emitting media. A better accuracy is achieved in the determination of the total exchange areas by using the proposed smoothing Monte Carlo method. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
41. Experimental study of optimum spacing problem in the cooling of simulated electronic package.
- Author
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Chen, S., Liu, Y., Chan, S. F., Leung, C. W., and Chan, T. L.
- Abstract
An experimental investigation has been performed to determine the effects of different arrangements of obstacles on the cooling of simulated electronic package. The considered simulated electronic package consisted of a channel formed by two parallel plates. The bottom plate is attached with five identical electrically heated square obstacles, which are perpendicular to the mean airflow and arranged with different side-to-side distances. The experimental results show that the conventional equi-spaced arrangement might not be the optimum option and should be avoided. A better thermal performance could be obtained when the side-to-side distances between the obstacles followed a geometric series. For example, at Re=800, the highest temperature of the optimum arrangement could be reduced by 12% compare to the equi-spaced arrangement and the maximum temperature difference among the five obstacles is lower than that of equi-spaced arrangement by 32.1%. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
42. Crystallization kinetics of amorphous nanostructured Pd40.5Ni40.5P19 alloys.
- Author
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Ngai, H. W., Leung, C. C., Guo, W. H., and Kui, H. W.
- Published
- 2001
- Full Text
- View/download PDF
43. Forced convection and friction in triangular duct with uniformly spaced square ribs on inner surfaces.
- Author
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Leung, C. W., Chan, T. L., and Chen, S.
- Abstract
Experimental investigation had been conducted to study the steady-state forced convection heat transfer and pressure drop characteristics of the hydrodynamic fully-developed turbulent flow in the air-cooled horizontal equilateral triangular ducts, which were fabricated with the same length and hydraulic diameter. Inner surfaces of the ducts were fixed with square ribs with different side lengths of 6.35, 9.525 and 12.7 mm, respectively, and the uniform separation between the centre lines of two adjacent ribs was kept constant at 57.15 mm. Both the triangular ducts and the ribs were fabricated with duralumin. The experiments were performed with the hydraulic diameter based Reynolds number ranged from 3100 to 11300. The entire inner wall of the duct was heated uniformly, while the outer surface was thermally insulated. It was found that the Darcy friction factor of the duct was increasing rather linearly with the rib size, and forced convection could be enhanced by an internally ribbed surface. However, the heat transfer enhancement was not proportional to the rib size but a maximum forced convection heat transfer augmentation was obtained at the smallest rib of 6.35 mm. Non-dimensional expressions for the determination of the steady-state heat transfer coefficient and Darcy friction factor of the equilateral triangular ducts, which were internally fabricated with uniformly spaced square ribs of different sizes, were also developed. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
44. Interfacial changes of optical fibers in the cementitious environment.
- Author
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Leung, C. K. Y. and Darmawangsa, D.
- Subjects
OPTICAL fibers ,STRAINS & stresses (Mechanics) ,MATRIX mechanics ,SURFACE coatings ,CONCRETE analysis - Abstract
Embedded optical fiber sensors have recently been employed for strain and crack monitoring in concrete structures. The performance of the sensor is strongly affected by the fiber/matrix interface. For strain monitoring, effective stress transfer between fiber and matrix is required. A high interfacial bond is therefore desirable. On the other hand, crack sensing may rely on fiber debonding and bending, which is only possible with a weak interfacial bond. In the cementitious environment, the interfacial properties are known to vary with time, and this may affect the long-term performance of embedded optical sensors. The objective of the present investigation is to study the interfacial changes when specimens containing embedded optical fibers (with different coatings) are subject to different environmental conditions including wet curing, wetting/drying and freezing/thawing. Fibers removed from the matrix are examined under the SEM. Also, fiber pull-out specimens are prepared and tested. The results show that the fiber pull-out test can reveal significant changes in interfacial behaviour that cannot be detected from SEM examination. The pull-out test is therefore demonstrated to be a useful technique for the characterization of time dependent interfacial behavior for embedded optical fiber sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
45. Formation of Bulk Nanostructured Materials by Rapid Solidification.
- Author
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Guo, W. H., Chua, L. F., Leung, C. C., and Kui, H. W.
- Published
- 2000
- Full Text
- View/download PDF
46. Assessment for Learning: Using Solo Taxonomy to Measure Design Performance of Design & Technology Students.
- Author
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Leung, C. F.
- Subjects
- *
ABILITY grouping (Education) , *INSIGHT , *PROBLEM-based learning , *DESIGN , *MANUAL training , *TECHNICAL education - Abstract
One objective of Design & Technology (D&T) is to enable students to be inventive in designing practical solutions to problems. D&T is viewed as being successful when students can demonstrate the ability to recognize problems, undertake inquiries by themselves, and contribute ideas accordingly. This article will discuss a study which investigated an alternative approach to assessing students' design performances. In the study, a new item format was designed and a new criterion framework of assessment based on Biggs' SOLO Taxonomy was developed. The evidence from this study indicates strong face validity for the new approach which maps closely to the goals and purposes of learning D&T. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
47. The Employee Stress and Alcohol Project: the development of a computer-based alcohol abuse prevention program for employees.
- Author
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Matano, Robert A., Futa, Kristine T., Wanat, Stanley F., Mussman, Lisa M., Leung, Cynthia W., Matano, R A, Futa, K T, Wanat, S F, Mussman, L M, and Leung, C W
- Subjects
EMPLOYEES ,SUBSTANCE use of employees ,EMPLOYEE health promotion ,ALCOHOL drinking - Abstract
The Employee Stress and Alcohol Project (ESAP) developed an interactive computer-based alcohol abuse prevention and early intervention program accessible to employees over the Internet. Behavioral health research recommends that specialists develop and provide comprehensive yet cost-effective approaches to alcohol abuse prevention, early intervention, and treatment within the context of workplace managed care. ESAP is implementing this web site for a diverse 8,567-employee work site. ESAP's web site enables employees to self-assess their stress levels, coping styles, and risk for alcohol-related problems. It provides personalized feedback, recommendations, mini-workshops, a drinking journal, links to other online resources, and an interactive forum for direct participant-to-participant communication. ESAP's web site provides resources for employees who are concerned about another individual's drinking as well as information about adolescent alcohol use. This article discusses the implications of incorporating the ESAP web site into worksite alcohol abuse prevention and early intervention programming. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
48. An optimum spacing problem for five chips on a horizontal substrate in a vertically insulated enclosure.
- Author
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Liu, Y., Phan-Thien, N., Leung, C. W., and Chan, T. L.
- Abstract
The optimum spacing problem for five heated chips rested on a conductive substrate in a vertically insulated enclosure filled with air is solved by an operator-splitting pseudo-time-stepping finite element method, which automatically satisfies the continuity of the interfacial temperature and heat flux. It is found that the conventional equi-spaced arrangement is not an optimum option. An optimum thermal performance can be obtained when the center-to-center distances between the chips follow a geometric series. The maximum relative temperature drop in the optimum configuration can be as much as 20% of the equi-spaced arrangement. [ABSTRACT FROM AUTHOR]
- Published
- 1999
- Full Text
- View/download PDF
49. Mixed convection from upward flow of hot air to a cooled vertical pipe.
- Author
-
Chan, T. L. and Leung, C. W.
- Abstract
An experimental study had been carried out to investigate the buoyancy-opposed mixed convection from an upward flow of hot air to a vertical pipe with a cooled surface. The investigation covered a wide range of flow regime, ranging from the “free convection significant” to the “forced convection significant” conditions. Reynolds number of the flow extended from 966 to 14780, whereas the Buoyancy parameter, Ω [=Gr
d /(Red )2 ], varied from 0.008 to 2.77. A steady stream of hot air at a moderate pressure and a Prandtl number of 0.707 was arranged to flow upward through a vertical steel pipe, whose external wall was cooled uniformly by ambient air at 20°C. Test section of the vertical pipe was 1625 mm long with an internal diameter of 156 mm and an external diameter of 166 mm. Air temperature at inlet of the test section was varied from 40°C to 70°C. Both radial temperature and velocity profiles of the airflow were measured at inlet and exit of the test section respectively. Temperatures along the pipe wall were also measured. Non-dimensional expression for the prediction of the average heat transfer coefficient of the mixed convection from an upward flow of hot air to a vertical pipe with a cooled surface was developed from the experimental results. Convection heat transfer was found to impair when the flow is laminar and was enhanced for turbulent flow condition. [ABSTRACT FROM AUTHOR]- Published
- 1999
- Full Text
- View/download PDF
50. Use of home automated intermittent peritoneal dialysis in the treatment of end stage renal failure.
- Author
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Li, P., Wang, A., Leung, C., Lui, S., and Lai, K.
- Abstract
We report our retrospective analysis of 16 uraemic patients who were treated with home automated intermittent peritoneal dialysis (IPD) from 1988 to 1993. Six patients were diabetic. The mean age was 58.5 years. The reasons for home automated IPD were: old age, poor eyesight, low intelligence or poor dexterity, family or patient request and old stroke. It took an average of 8.8 sessions to train the helper. The mean frequency of the home IPD was once every 5.8 days with a mean volume of 48 litres of dialysate used during each dialysis. There were 3 peritonitis episodes making the peritonitis rate once every 93 patient months. Four patients were still on home IPD and two were transplanted. Ten patients died of stroke, myocardial infarction, tuberculosis, chronic obstructive lung disease or suicide. A low plasma albumin is the only significant parameter in the early mortality group. Such high mortality can be accounted for by the fact that patients were older and forty per cent were diabetic. We conclude that home automated IPD can be an alternative for some patients in whom other modes of dialysis are difficult. [ABSTRACT FROM AUTHOR]
- Published
- 1994
- Full Text
- View/download PDF
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