Sun Exposure and the Risk of Prostate Cancer in the Singapore Prostate Cancer Study: a Case-control Study

Chia, Sin-Eng,Wong, Kin-Yoke,Cheng, Christopher,Lau, Weber,Tan, Puay-Hoon Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Background: Most of the epidemiology studies on the effects of sun exposure and prostate cancer were conducted among the temperate countries of North America and Europe. Little is known about the influence on Asian populations. The purpose of current study was to evaluate any association of sun exposure with risk of prostate cancer in Chinese, Malays and Indians who reside in the tropics. Methods: The Singapore Prostate Cancer Study is a hospital-based case-control study of 240 prostate cancer incident cases and 268 controls conducted in Singapore between April 2007 and May 2009. Detailed information on outdoor activities in the sun, skin colour, sun sensitivity and other possible risk factors were collected in personal interviews. Cases were further classified by Gleason scores and TNM staging. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression analysis, adjusted for age, ethnicity, education, family history of any cancers, BMI and skin colour. Results: We found that prostate cancer risk was increased in subjects with black/dark-brown eyes (OR 5.88, 95%CI 3.17-10.9), darker skin colour e.g. tan/dark brown/black (OR 7.62, 95%CI 3.41-17.0), frequent sunburn in lifetime (OR 4.30, 95%CI 1.7-11.2) and increased general sun exposure in adulthood per week (OR 2.03, 95%CI 1.09-3.81). The increased risk was consistent for high grade tumours and advanced stage prostate cancers. Conclusion: The findings from this study suggest that excessive sun exposure is a risk factor for prostate cancer in Asians.

Theoretical discussion on forms of cultural capital in Singapore

Cheng Yong Tan 서울대학교 교육연구소 2013 Asia Pacific Education Review Vol.14 No.2

This article is a theoretical discussion on five forms of cultural resources that constitute cultural capital for children in the meritocratic yet stratified society of Singapore. These five forms of cultural capital are namely ‘academic’ tastes and leisure preferences, use of Standard English, access to and dispositions toward information communication technology, acquisition of learning skills, and confidence/learning dispositions. They cover two important aspects of cultural capital—namely objectified and embodied components—that may vary in levels with social class and that mediate the influence of social class on children’s academic achievement. Equally importantly, the focus on one societal context—in this case, Singapore—recognizes the contextual specificities of cultural capital in form and consumption pattern among individuals.

General Stabilization for Stochastic System With Input Delay and Multiplicative Noise: Continuous-time Case

Cheng Tan,Jianying Di,Zhengqiang Zhang,Wing Shing Wong 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.2

This paper investigates the general stabilization issues for continuous-time stochastic dynamics whose input delay and multiplicative noise in control variable exist simultaneously. On the one hand, we present a set of necessary and sufficient conditions for stabilizing the considered stochastic dynamics in mean-square sense. Different from many previous works, one significant innovation is that our control policy is designed as the feedback of an extended state that contains the current available state and some past control information. On the other hand, another important innovation is that we for the first time generalize the notions of critical stabilization and essential destabilization to stochastic time-delay model in terms of spectral analysis technique, while the related necessary and sufficient stabilization conditions are derived respectively.

Numerical analysis of RC hammer head pier cap beams extended and reinforced with CFRP plates

Cheng Tan,Jia Xu,Riyad S. Aboutaha 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.25 No.5

This paper presents a numerical study on structural behavior of hammer head pier cap beams, extended on verges and reinforced with carbon fiber reinforced polymer (CFRP) plates. A 3-D finite element (FE) model along with a simplified analytical model are presented. Concrete damage plasticity (CDP) was adapted in the FE model and an analytical approach predicting the CFRP anchor strength was adapted in both FE and analytical model. Total five quarter-scaled pier cap beams with various CFRP reinforcing schemes were experimentally tested and analyzed with numerical approaches. Comparison between experimental results, FE results, analytical results and current ACI guideline predictions was presented. The FE results showed good agreement with experimental results in terms of failure mode, ultimate capacity, load-displacement response and strain distribution. In addition, the proposed strut-and-tie based analytical model provides the most accurate prediction of ultimate strength of extended cap beams among the three numerical approaches.

Determining the Utility of the Guillain-Barré Syndrome Classification Criteria

Cheng-Yin Tan,Siti Nur Omaira Razali,Khean Jin Goh,Nortina Shahrizaila 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.2

Background and Purpose Several variants of Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) exist, but their frequencies vary in different populations and do not always meet the inclusion criteria of the existing diagnostic criteria. However, the GBS classification criteria by Wakerley and colleagues recognize and define the clinical characteristics of each variant. We applied these criteria to a GBS and MFS cohort with the aim of determining their utility. Methods Consecutive GBS and MFS patients presenting to our center between 2010 and 2020 were analyzed. The clinical characteristics, electrophysiological data, and antiganglioside antibody profiles of the patients were utilized in determining the clinical classification. Results This study classified 132 patients with GBS and its related disorders according to the new classification criteria as follows: 64 (48.5%) as classic GBS, 2 (1.5%) as pharyngeal-cervical- brachial (PCB) variant, 7 (5.3%) as paraparetic GBS, 29 (22%) as classic MFS, 3 (2.3%) as acute ophthalmoparesis, 2 (1.5%) as acute ataxic neuropathy, 2 (1.5%) as Bickerstaff brainstem encephalitis (BBE), 17 (12.9%) as GBS/MFS overlap, 4 (3%) as GBS/BBE overlap, 1 (0.8%) as MFS/PCB overlap, and 1 (0.8%) as polyneuritis cranialis. The electrodiagnosis was demyelinating in 55% of classic GBS patients but unclassified in 79% of classic MFS patients. Anti-GM1, anti-GD1a, anti-GalNAc-GD1a, and anti-GD1b IgG ganglioside antibodies were more commonly detected in the axonal GBS subtype, whereas the anti-GQ1b and anti-GT1a IgG ganglioside antibodies were more common in classic MFS and its subtypes. Conclusions Most of the patients in the present cohort met the criteria of either classic GBS or MFS, but variants were seen in one-third of patients. These findings support the need to recognize variants of both syndromes in order to achieve a more-complete case ascertainment in GBS.

A NEW SOLUTION METHOD FOR STATE EQUATIONS OF NONLINEAR SYSTEM

Zhang, Cheng-Hui,Tan, Cheng-Hui,Cui, Na-Xin 한국전산응용수학회 1999 Journal of applied mathematics & informatics Vol.6 No.1

Along with the computation and analysis for nonlinear system being more and more involved in the fields such as automation control electronic technique and electrical power system the nonlin-ear theory has become quite a attractive field for academic research. In this paper we derives the solutions for state equation of nonlinear system by using the inverse operator expression of the so-lutions is obtained. An actual computation example is given giving a comparison between IOM and Runge-kutta method. It has been proved by our investigation that IOM has some distinct advantages over usual approximation methods in that it is computationally con-venient rapidly convergent provides accurate solutions not requiring perturbation linearization or the massive computation inherent in discrietization methods such as finite differences. So the IOM pro-vides an effective method for the solution of nonlinear system is of potential application valuable in nonlinear computation.

Classification of Postponement Strategies and Performance Metrics Framework

Cheng Zhang,Gek Woo Tan 한국경영정보학회 2001 한국경영정보학회 학술대회논문집 Vol.2001 No.-

Protective effect of procyanidin B2 on hydrogen peroxide (H2O2)-induced oxidative damage in MCF-7 cells

Tan Jia-qi,Li Peng-cheng,Li Qian,Tang Jin-tian,Xue Hong-kun 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.5

The aim of this study is to assess the cytoprotection and potential molecular mechanisms of procyanidin B2 ( PCB2) on hydrogen peroxide ( H2O2)-induced oxidative damage in MCF-7 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the viability of MCF-7 cell exposure to H2O2 or PCB2. We measured the antioxidant properties of PCB2 by determining the activities of SOD, GSH-Px, LDH and MDA levels, and evaluated apoptosis and intracellular reactive oxygen species (ROS) levels. The related proteins expression levels were monitored by Western blot. MCF-7 cells induced with H2O2 had a remarkable decrease in cell viability that was suppressed when it was interfered with PCB2 (0.1–10.0 μM). PCB2 interference memorably and dose-dependently inhibited H2O2- induced LDH leakage, ROS and MDA overproduction, while PCB2 markedly increased H2O2- induced the activities of SOD and GSH-Px. Eventually, H2O2 prominently down-regulated the ratio of Bcl-2/Bax and the relative proteins expression levels of Nrf2, GCLC, NQO1 and HO-1, and up-regulated the relative proteins expression levels of cytochrome c, caspase-3 and Keap1. However, the relative expression levels of these proteins were reversed in PCB2- interfered MCF-7 cells. This study implied that protective effect of PCB2 on H2O2- induced oxidative damage in MCF-7 cells might be related to inhibition of mitochondria-dependent apoptosis, activation of Keap1/Nrf2/HO-1 signaling pathway and improvement of the antioxidant enzymes activities.

Calibration Practices in Clinical Mass Spectrometry: Review and Recommendations

Cheng Wan Ling,Markus Corey,Lim Chun Yee,Tan Rui Zhen,Sethi Sunil Kumar,Loh Tze Ping 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.1

Background: Calibration is a critical component for the reliability, accuracy, and precision of mass spectrometry measurements. Optimal practice in the construction, evaluation, and implementation of a new calibration curve is often underappreciated. This systematic review examined how calibration practices are applied to liquid chromatography-tandem mass spectrometry measurement procedures. Methods: The electronic database PubMed was searched from the date of database inception to April 1, 2022. The search terms used were “calibration,” “mass spectrometry,” and “regression.” Twenty-one articles were identified and included in this review, following evaluation of the titles, abstracts, full text, and reference lists of the search results. Results: The use of matrix-matched calibrators and stable isotope-labeled internal standards helps to mitigate the impact of matrix effects. A higher number of calibration standards or replicate measurements improves the mapping of the detector response and hence the accuracy and precision of the regression model. Constructing a calibration curve with each analytical batch recharacterizes the instrument detector but does not reduce the actual variability. The analytical response and measurand concentrations should be considered when constructing a calibration curve, along with subsequent use of quality controls to confirm assay performance. It is important to assess the linearity of the calibration curve by using actual experimental data and appropriate statistics. The heteroscedasticity of the calibration data should be investigated, and appropriate weighting should be applied during regression modeling. Conclusions: This review provides an outline and guidance for optimal calibration practices in clinical mass spectrometry laboratories.

Noise Analysis and Structure Optimization for Sleeve Type Regulating Valve Based on CFD

Cheng Wu,Gang Yang,Fabing Tan,Baoren Li 유공압건설기계학회 2015 유공압건설기계학회 학술대회논문집 Vol.2015 No.10

According to the noise problems of sleeve type regulating valve, this paper utilizes the method of Computational Fluid Dynamics(CFD) based on the RNG k-ε turbulence model to analyze flow field characteristics of sleeve type regulating valve, then the window shape and valve core angle is optimized. The analysis shows that the shape of sleeve window has a significant effect on the noise of regulating valve. In the same boundary conditions, the noise of the new valve is 13dB lower than the original valve, and the noise performance of the sleeve type regulating valve gets significant improvement. And its flow characteristic curve is obtained by simulation, which shows that the optimized sleeve flow regulating valve has good linear flow characteristic. The research in this paper can be used for reference for the design of sleeve type regulating valve with low noise and high performance.