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202. Spectral-Domain OCT Measurements in Alzheimer’s Disease

Author

Chan, Victor T.T., primary, Sun, Zihan, additional, Tang, Shumin, additional, Chen, Li Jia, additional, Wong, Adrian, additional, Tham, Clement C., additional, Wong, Tien Y., additional, Chen, Christopher, additional, Ikram, M. Kamran, additional, Whitson, Heather E., additional, Lad, Eleonora M., additional, Mok, Vincent C.T., additional, and Cheung, Carol Y., additional

Published
2019
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206. Proceedings of the 50th Winter Simulation Conference

Author

Chan, Victor, D'Ambrogio, Andrea, Zacharewicz, Grégory, Mustafee, Navonil, Dept. of Computer Science, Rensselaer Polytechnic Institute, NY, USA, Rensselaer Polytechnic Institute (RPI), Tsinghua University [Beijing] (THU), University of Rome 'Tor Vergeta', Laboratoire de l'intégration, du matériau au système (IMS), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université Sciences et Technologies - Bordeaux 1, and University of Exeter Business School

Subjects
INFORMS, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation
Abstract

International audience; From experimentation to theory; standards and advanced methodologies, modeling and simulation is continually pushing the envelope of the available technologies, as many sectors have growing needs to process, visualize, make readable, understand, and deploy complex models that use immense amounts of data. These players need to transform data into hypothesis building and critical decision-making, and to change their models in response to new hypotheses, usually involving multiple highly specialized experts working together in geographically distant areas.After 50 years, we are now beyond Modeling and Simulation using Grid and Cloud computing, Web-based and distributed simulation and other recent technologies. We need to deal with computing power and storage in heterogeneous environments, resources virtualization; services consumed on demand (with minimal limitation for resource location), power issues, massive datasets. We face new challenges as we have ubiquitous processors that can process applications on demand.WSC 2017 focus is on addressing how to achieve the goal of having Simulation Everywhere!

Published
2017

209. Renal failure caused by mushroom poisoning

Author

Leathem, Anne M., Purssell, Roy A., Chan, Victor R., and Kroeger, Paul D.

Subjects
Mushrooms, Poisonous -- Health aspects, Acute renal failure -- Causes of, Environmental issues, Health, Pharmaceuticals and cosmetics industries
Abstract

Background: In the Pacific Northwest region of the US and in southwestern British Columbia, Canada, isolated cases of renal failure have occurred following ingestion of wild mushrooms. We report four cases in which toxic mushrooms were mistaken for the edible pine mushroom or matsutake (Tricholoma magnivelare). Case Reports: Gastrointestinal symptoms started five to eight hours after ingestion and continued for several days. Three of the four patients were found to be in renal failure when they presented to the emergency department 5-6 days post ingestion. One patient, an elderly diabetic, had renal dysfunction the day following ingestion. All patients received hemodialysis and supportive care and regained renal function. Discussion: Symptoms and time of onset are similar to those reported in previous cases of Amanita smithiana poisoning. This suggests that the mushroom involved in these cases may also be Amanita smithiana which contains nephrotoxic compounds. In one of the cases, stern ends of the mushrooms were available for examination. Cellular elements conforming to those described as being present in the species Amanita smithiana were seen on light microscopy. Conclusion: Mushroom field guides warn against mistaking Amanita smithiana for pine mushrooms. They are similar in size, color and habitat. It appears possible that Amanita smithiana mushrooms were eaten instead of pine mushrooms in these cases., INTRODUCTION Until recently, serious toxicity from mushroom poisoning in North America has been associated primarily with hepatotoxicity from ingestion of amatoxin-containing mushrooms.[1-4] In the Pacific Northwest region of the US [...]

Published
1997

210. Hydrolysis of Ferulic Acids in Corn Fiber by a Metagenomic Feruloyl Esterase.

Author

Wong, Dominic W. S., Chan, Victor J., and Liao, Hans

Abstract

A feruloyl esterase (FAE) gene was isolated from rumen microbial metagenome that consisted of 774 bp encoding 258 amino acid residues. The gene was subcloned into pET 32b vector, expressed in Escherichia. coli, and the enzyme was purified in active form. Homology modeling showed that the FAE contained the catalytic triad composed of Ser80- His236-Asp177, and a classical Gly-X-Ser-X-Gly nucleophile motif commonly found in esterases. Under optimum pH and temperature (pH 7.0, 40 °C), 1 nmole FAE catalyzed the release of 19.75 ± 0.24 µg ferulic acid (FA) from 100 mg corn fiber (CF) in 1 h, which represents 3.5% of FA present in saponified CF. Addition of GH10 endoxylanase (XYN) to 0.5 nmole FAE enhanced the yield by 1.1 fold, equivalent to a 5% increase in FA release. Using CF pretreated with hot water, the synergistic effect of adding XYN resulted in 59.0 ± 0.2 mg FA/100 mg CF (5 nmole XYN, 0.5 nmole FAE), equivalent to a 4-fold increase compared to using the untreated CF substrate under the same reaction conditions. [ABSTRACT FROM AUTHOR]

Published
2021
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212. The effects of teams' initial characterizations of interactions on product development performance

Author

Songhori, Mohsen Jafari, Jalali, Mohammad S., Terano, Takao, Chan, Victor, D'Ambrogio, Andrea, Zacharewicz, Gregory, and Mustafee, Navonil

Abstract

Coordinated search processes are pervasive in both organizations and product development projects. In such processes, designers with different specialties learn about their interdependent alternatives through a mutual adjustment process. In the context of a product development with several teams developing the new product’s subsystems, and using reinforcement learning and agent-based simulation modeling, this study looks at the performance effects of design teams’ initial mental characterizations about subsystem interactions. The focus is on two initial mental models, one in which teams over-weight their own subsystem’s element interactions, and another, in which teams over-weighting interactions between subsystems. The results indicate that both initial representations have critical performance consequences for product development. Specifically, teams prioritizing their interactions of their own subsystem’s elements gain short-run performance benefits as they converge to a local optimum in a short time period. Contrarily, over-weighting between-subsystem interactions leads to a tendency for teams to have long-run performance advantages.

Published
2017

219. 208 - Effectiveness of Volunteer-Delivered Telephone Reminders on Adherence to Colorectal Cancer Screening: A Randomized Controlled Trial

Author

Wong, Martin C., primary, Lam, Thomas Y., additional, Ching, Jessica Y., additional, Chan, Victor C., additional, Ng, Simpson K.C., additional, Hui, Shu Ning, additional, Luk, Arthur K.C., additional, Huang, Junjie, additional, Huang, Jason, additional, Wu, Justin C., additional, Chan, Francis K., additional, and Sung, Joseph J., additional

Published
2018
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221. Tolerogenic Nanoparticles Induce Antigen-Specific Regulatory T Cells and Provide Therapeutic Efficacy and Transferrable Tolerance against Experimental Autoimmune Encephalomyelitis

Author

LaMothe, Robert A., primary, Kolte, Pallavi N., additional, Vo, Trinh, additional, Ferrari, Joseph D., additional, Gelsinger, Tracy C., additional, Wong, Jodie, additional, Chan, Victor T., additional, Ahmed, Sinthia, additional, Srinivasan, Aditi, additional, Deitemeyer, Patrick, additional, Maldonado, Roberto A., additional, and Kishimoto, Takashi K., additional

Published
2018
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226. Using Retinal Imaging to Study Dementia

Author

Chan, Victor T.T., primary, Tso, Tiffany H.K., primary, Tang, Fangyao, primary, Tham, Clement, primary, Mok, Vincent, primary, Chen, Christopher, primary, Wong, Tien Y., primary, and Cheung, Carol Y., primary

Published
2017
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229. Development of Generic Competencies and its Association with Secondary Public Examination Performance: A Tertiary STEM Freshmen's Perspective

Author

Ho, W. T., Chan, Victor C W, Lam, Derek S Y, So, Joseph C H, Ng, Kris, Ho, W. T., Chan, Victor C W, Lam, Derek S Y, So, Joseph C H, and Ng, Kris

Abstract

The present paper examines the relationship between development of various kinds of generic competencies, and its association with secondary public examination performance, using a case study of tertiary STEM freshmen in Hong Kong. The result shows different trajectories of generic competencies development between STEM and non-STEM students prior to their entrance to tertiary education. The findings also show that Liberal Studies, as a key public examination subject, has positive association with the development of both creative thinking as well as critical thinking among STEM students. © 2016 IEEE.

Published
2017

230. Colorectal Cancer Screening Based on Age and Gender

Author

Wong, Martin C.S., Ching, Jessica Y.L., Chan, Victor C.W., Lam, Thomas Y.T., Luk, Arthur K.C., Wong, Sunny H., Ng, Siew C., Ng, Simon S.M., Wu, Justin C.Y., Chan, Francis K.L., and Sung, Joseph J.Y.

Subjects
Male, Economic Evaluation Study, Cost-Benefit Analysis, Patient Selection, Age Factors, Colonoscopy, Middle Aged, United States, Sex Factors, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Humans, Female, Colorectal Neoplasms, Sigmoidoscopy, Early Detection of Cancer, Research Article, Aged, Neoplasm Staging
Abstract

Supplemental Digital Content is available in the text, We evaluated whether age- and gender-based colorectal cancer screening is cost-effective. Recent studies in the United States identified age and gender as 2 important variables predicting advanced proximal neoplasia, and that women aged

Published
2016

231. Determinants of Bowel Preparation Quality and Its Association With Adenoma Detection

Author

Wong, Martin C.S., Ching, Jessica Y.L., Chan, Victor C.W., Lam, Thomas Y.T., Luk, Arthur K.C., Tang, Raymond S.Y., Wong, Sunny H., Ng, Siew C., Ng, Simon S.M., Wu, Justin C.Y., Chan, Francis K.L., and Sung, Joseph J.Y.

Subjects
Adenoma, Male, Cathartics, Colonic Neoplasms, Observational Study, Humans, Female, Colonoscopy, Prospective Studies, Middle Aged, Research Article, Aged
Abstract

The predictors of poor bowel preparation in colorectal cancer screening participants have not been adequately studied, and the association between the quality of bowel preparation and adenoma detection has not been firmly established. This study examined the determinants of poor bowel preparation, and evaluated its relationship with adenoma detection. We included subjects aged between 50 and 70 years who received colonoscopy between 2008 and 2014 in a colorectal cancer screening program in Hong Kong. The quality of the bowel preparation was assessed by colonoscopists, and the factors associated with poor bowel cleansing were evaluated by a binary logistic regression analysis. A multivariate regression model was constructed to evaluate if poor bowel preparation was associated with detection of colorectal neoplasia. From 5470 screening participants (average age 57.7 years, SD 4.9), 1891 (34.6%) had poor or fair bowel preparation. The average cecal intubation time was 7.0 minutes (SD 5.4; range 1.22–36.9 minutes) and the average colonoscopy withdrawal time was 10.8 minutes (SD 6.9; range 6.0–107.0 minutes). Among all, 26.5% had colorectal neoplasia and 5.5% had advanced neoplasia. Older age (≥60 years; adjusted odds ratio [AOR] = 1.19–1.38, P = 0.02–0.04), male sex (AOR = 1.38, 95% confidence interval [CI] 1.19–1.60, P

Published
2016

235. Effectiveness of Telephone Reminders vs. Short Message Service vs. Usual Care on Persistent Adherence to Colorectal Cancer Screening: A Randomized Clinical Trial

Author

Wong, Martin C, primary, Ching, Jessica, additional, Chan, Victor C.W., additional, Wong, John C., additional, Kyaw, Moe H., additional, Lam, Thomas Y., additional, Ng, Simpson K.C., additional, Hui, Zero, additional, Luk, Arthur K.C., additional, Liang, Miaoyin, additional, Fang, Yuan, additional, Huang, Jason L., additional, Wu, Justin C., additional, Chan, Francis K., additional, and Sung, Joseph J., additional

Published
2017
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236. Adenoma Detection Rate among Colonoscopy for Positive Screening Fit is Higher than for Direct Screening Colonoscopy: A Call for Differential ADR Targets

Author

Wong, John C., primary, Wong, Martin C., additional, Ching, Jessica, additional, Chan, Victor C.W., additional, Ng, Siew C., additional, Tang, Raymond S., additional, Kyaw, Moe H., additional, Wong, Sunny H., additional, Lau, James Y., additional, Wu, Justin C., additional, Chan, Francis K., additional, and Sung, Joseph J., additional

Published
2017
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241. Metagenomic discovery of feruloyl esterases from rumen microflora.

Author

Wong, Dominic W. S., Chan, Victor J., and Liao, Hans

Subjects
*ESTERASES, *ARABINOXYLANS, *FERULIC acid, *HYDROXYCINNAMIC acids, *ESTERS, *ESCHERICHIA coli, *MICROBIAL enzymes
Abstract

Feruloyl esterases (FAEs) are a key group of enzymes that hydrolyze ferulic acids ester-linked to plant polysaccharides. The cow's rumen is a highly evolved ecosystem of complex microbial microflora capable of converting fibrous substances to energy. From direct cloning of the rumen microbial metagenome, we identified seven active phagemids conferring feruloyl esterase activity. The genomic inserts ranged from 1633 to 4143 bp, and the ORFs from 681 to 1359 bp. BLAST search reveals sequence homology to feruloyl esterases and esterases/lipases identified in anaerobes. The seven genes were expressed in Escherichia coli, and the proteins were purified to homogeneity. The FAEs were found to cover types B, C, and D in the feruloyl esterase classification system using model hydroxycinnamic acid esters. The release of ferulic acid (FA) catalyzed by these enzymes was established using natural substrates corn fiber (CF) and wheat insoluble arabinoxylan (WIA). Three of the enzymes were demonstrated to cleave diferulates and hence the capability to break down Araf-FA-FA-Araf cross-links. The wide variation in the sequence, activity, and substrate specificity observed in the FAEs discovered in this study is a confirming evidence that combined actions of a full range of FAE enzymes contribute to the high-efficiency fiber digestion in the rumen microbial ecosystem. [ABSTRACT FROM AUTHOR]

Published
2019
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242. Image-based multi-scale mechanical analysis of strain amplification in neurons embedded in collagen gel.

Author

Chan, Victor W. L., Tobin, William R., Zhang, Sijia, Winkelstein, Beth A., Barocas, Victor H., Shephard, Mark S., and Picu, Catalin R.

Subjects
*NEURONS, *COLLAGEN, *EXTRACELLULAR matrix, *STRAINS & stresses (Mechanics), *SIMULATION methods & models
Abstract

A general multi-scale strategy is presented for modeling the mechanical environment of a group of neurons that were embedded within a collagenous matrix. The results of the multi-scale simulation are used to estimate the local strains that arise in neurons when the extracellular matrix is deformed. The distribution of local strains was found to depend strongly on the configuration of the embedded neurons relative to the loading direction, reflecting the anisotropic mechanical behavior of the neurons. More importantly, the applied strain on the surrounding extracellular matrix is amplified in the neurons for all loading configurations that are considered. In the most severe case, the applied strain is amplified by at least a factor of 2 in 10% of the neurons' volume. The approach presented in this paper provides an extension to the capability of past methods by enabling the realistic representation of complex cell geometry into a multi-scale framework. The simulation results for the embedded neurons provide local strain information that is not accessible by current experimental techniques. [ABSTRACT FROM AUTHOR]

Published
2019
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245. Cysteine protease inhibitors as chemotherapy: Lessons from a parasite target

Author

SELZER, PAUL M., PINGEL, SABINE, HSIEH, IVY, UGELE, BERNHARD, CHAN, VICTOR J., ENGEL, JUAN C., BOGYO, MATTHEW, RUSSELL, DAVID G., SAKANARI, JUDY A., and MCKERROW, JAMES H.

Subjects
Proteases -- Research, Cysteine -- Research, Cancer -- Causes of, Papain -- Analysis, Chemotherapy -- Usage, Science and technology
Abstract

Papain family cysteine proteases are key factors in the pathogenesis of cancer invasion, arthritis, osteoporosis, and microbial infections. Targeting this enzyme family is therefore one strategy in the development of new chemotherapy for a number of diseases. Little is known, however, about the efficacy, selectivity, and safety of cysteine protease inhibitors in cell culture or in vivo. We now report that specific cysteine protease inhibitors kill Leishmania parasites in vitro, at concentrations that do not overtly affect mammalian host cells. Inhibition of Leishmania cysteine protease activity was accompanied by defects in the parasite's lysosome/endosome compartment resembling those seen in lysosomal storage diseases. Colocalization of anti-protease antibodies with biotinylated surface proteins and accumulation of undigested debris and protease in the flagellar pocket of treated parasites were consistent with a pathway of protease trafficking from flagellar pocket to the lysosome/endosome compartment. The inhibitors were sufficiently absorbed and stable in vivo to ameliorate the pathology associated with a mouse model of Leishmania infection.

Published
1999

246. Radiotherapy in Palliative Medicine

Author

Chan, Victor, Chan, Victor, Chan, Victor, and Chan, Victor

Abstract

Family doctors should know the indications of palliative radiotherapy in order to refer appropriately. They must answer questions about side effects and manage them when the patient is back in the community. In palliative care, radiotherapy can curtail growth or even shrink the tumour temporarily bringing about relief of pain and other symptoms. It is indicated for spinal cord compression, cerebral metastases, superior vena cava obstruction, bone metastases and pathological fracture; for control of haemorrhage, fungation and ulceration as well as relief of obstruction of ducts, hollow viscera, blood and lymphatic vessels. Management of the common acute side effects are discussed. The patients usually do not live long enough for late side effects to occur.

Published
2002

247. Chemotherapy in Palliative Medicine

Author

Chan, Victor, Chan, Victor, Chan, Victor, and Chan, Victor

Abstract

With advances in chemotherapy agents and bone marrow support, more cancer patients are indicated for curative or palliative chemotherapy. Family physicians should know about the indications and side effects, so that early referral for treatment can be made and side effects can be managed while the patient is in the community. The benefits of chemotherapy in palliative medicine and the management of common side effects are discussed.

Published
2002

248. Hypercalcaemia in Cancer Patient

Author

Chan, Victor, Chan, Victor, Chan, Victor, and Chan, Victor

Abstract

Hypercalcaemia is common in advanced cancer patients. It can also occur in breast cancer patients undergoing hormonal therapy and in the pre-terminal multiple myeloma patients. Because its symptoms are non-specific, it is often unrecognised. Successful treatment can result in improvement in quality of life. Family physicians should be aware of the clinical features so that they can provide timely management or referral. Its causes, pathophysiology, clinical features and management options are discussed.

Published
2001

249. Principle of Palliative Medicine

Author

Chan, Victor, Chan, Victor, Chan, Victor, and Chan, Victor

Abstract

Because of limited life expectancy and extent of multiple symptoms, the approach in palliative medicine is different from family medicine although there are many similarities between the two. The main goal of management is improving the quality of the patient's life through symptom control and dealing with psychosocial, spiritual and cultural factors. An interdisiplinary domiciliary service enables the patient to stay and die at home. Discussed in the paper are the general approach, communication problems, drug management and decision making process when palliative medicine is provided by family physicians.

Published
2001

250. Dyspnoea in Palliative Medicine

Author

Chan, Victor, Chan, Victor, Chan, Victor, and Chan, Victor

Abstract

Dyspnoea, common in advanced cancer patients, has many causes. Specific treatment of the cause is more effective than non-specific treatment alone. Detailed assessment for the cause is therefore mandatory. Morphine is the drug of choice for symptomatic relief of dyspnoea. Other respiratory sedatives, such as promethazine and chlorpromazine are helpful. Anxiolytics are given to anxious patients. Oxygen is helpful in certain conditions only. Non-drug management is equally important. Refractory dyspnoea in terminal stage can be managed by heavy sedation.

Published
2001

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