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Refined energy-conserving dissipative particle dynamics model with temperature-dependent properties and its application in solidification problem

Ng KC, Sheu TWH

Phys Rev E, 2017 Oct;96(4-1):043302.
PMID: 29347538 DOI: 10.1103/PhysRevE.96.043302

It has been observed previously that the physical behaviors of Schmidt number (Sc) and Prandtl number (Pr) of an energy-conserving dissipative particle dynamics (eDPD) fluid can be reproduced by the temperature-dependent weight function appearing in the dissipative force term. In this paper, we proposed a simple and systematic method to develop the temperature-dependent weight function in order to better reproduce the physical fluid properties. The method was then used to study a variety of phase-change problems involving solidification. The concept of the "mushy" eDPD particle was introduced in order to better capture the temperature profile in the vicinity of the solid-liquid interface, particularly for the case involving high thermal conductivity ratio. Meanwhile, a way to implement the constant temperature boundary condition at the wall was presented. The numerical solutions of one- and two-dimensional solidification problems were then compared with the analytical solutions and/or experimental results and the agreements were promising.
Variation of the platelet glycoprotein IIIa PI(A1/A2) allele frequencies in the three ethnic groups of Singapore

Lim J, Lal S, Ng KC, Ng KS, Saha N, Heng CK

Int J Cardiol, 2003 Aug;90(2-3):269-73.
PMID: 12957761

BACKGROUND: Polymorphisms of the glycoprotein IIIa receptor have been shown to be associated with differences in platelet aggregability. The PI(A2) variant of the polymorphism has been reported to be an inherited risk factor for acute coronary events. Although the allele frequency of this polymorphism is well documented in Caucasian populations, studies involving Asian Indians, Malays and Chinese are lacking. We studied 706 random male individuals to determine the genotypic distribution of this polymorphism in Singapore.
METHODS: Male subjects included in this study were drawn from those undergoing routine annual medical examinations offered by their employers. Venous blood was obtained from these patients after an overnight fast and from which genomic DNA was extracted. Genotyping was carried out by polymerase chain reaction (PCR) followed by digestion with restriction enzyme NciI. Personal and family medical history of the subjects were also taken.
RESULTS: The genotype distribution of the individuals studied was in accordance to a population at Hardy Weinberg equilibrium. The frequency of the PI(A2) allele was 0.1, 0.01 and 0.01 in the Indians, Malays and Chinese, respectively. The differences in frequencies of the PI(A2) variant are significant among different ethnic groups (P<0.001 for Indians vs. Chinese and Indians vs. Malays).
CONCLUSIONS: We observed a significantly higher frequency of the PI(A2) allele among Indians relative to the Chinese and Malays in Singapore. The effect of this genotype may partially explain the higher rate of ischaemic heart disease seen among Indians compared to the Chinese and Malay ethnic groups.
Erysipelothrix rhusiopathiae endocarditis presenting with stroke

Tan YA, Ng KC, Cheo SW, Low QJ, Chia YK

QJM, 2020 07 01;113(7):485-487.
PMID: 32053172 DOI: 10.1093/qjmed/hcaa025
Fulltext A case of dapsone-induced methaemoglobinaemia

Tan YA, Ng KC, Cheo SW, Khoo TT, Low QJ

Clin Med (Lond), 2020 09;20(5):519-521.
PMID: 32934050 DOI: 10.7861/clinmed.2020-0364

Methaemoglobinaemia is an uncommon but potentially serious condition. It can be caused by congenital or acquired cause. Drug-induced methaemoglobinaemia is the commonest cause of acquired methaemoglobinaemia. The clinical signs and symptoms of methaemoglobinaemia include dyspnoea, desaturation, presence of saturation gap, headache, nausea and seizures depending on level of serum methaemoglobinaemia. We illustrate a case of dapsone-induced methaemoglobinaemia and its successful treatment by intravenous methylene blue.
Fulltext Prevalence of hypertension among Malay adolescents in Putrajaya secondary schools, Malaysia, 2010

Rampal L, Ng KC, Nur Izzati I, Farah Izzati Z, Mohammad Nazrul I, Faisal I, et al.

Malaysian Journal of Medicine and Health Sciences, 2011;7(2):53-60.
MyJurnal

Background: In Malaysia, the prevalence of hypertension amongst adults aged 30 years and above has increased from 32.9% in 1996 to 40.5% in 2004 and to 42.6% in 2006. Information on the prevalence of hypertension among adolescents is lacking.
Objective: to determine the prevalence of hypertension among Malay secondary school students in Putrajaya.
Methods: A cross sectional study was carried out in Putrajaya, Malaysia. The sampling frame consisted of a list of all the 12 secondary schools in Putrajaya. Three schools were selected using table of random numbers. All Malay students aged 13 years old to 17 years old from the three selected school students were included in the study. Blood pressure was measured after the respondents had rested for at least 5 minutes using a standard mercury sphygmomanometer. Three blood pressure measurements were taken for each respondent. Systolic blood pressure [SBP] was defined as the average of three SBP readings and diastolic blood pressure [DBP] was defined as the average of three DBP readings. Data was analyzed using SPSS 18.
Results: The overall mean SBP and DBP were 108.9 mmHg and 63.2 mmHg respectively. The prevalence of pre-hypertension and hypertension among the male was 16.2% and 12.9% respectively as compared to 5.8% and 10.2% respectively in the females. The overall prevalence of prehypertension and hypertension was 11.1% and 11.6% respectively. The prevalence increased with age (p<0.05). There was a significant positive correlation between BMI and SBP (r = 0.52, r2 = 0.27, p= 0.001) and BMI and DBP (r = 0.38, r2 = 0.15, p= 0.001). The mean SBP was significantly higher in males (111.7 mmHg) as compared to 106 mmHg in females (p<0.001). The mean DBP in males (63.5 mmHg) was slightly higher as compared to 62.9 mmHg in females but the difference was not significant.
Conclusions: Prevalence of hypertension and pre-hypertension is high. There is an urgent need for implementation of a comprehensive CVD prevention program and routine blood pressure measurements should be taken in school children to improve the detection, prevention and treatment of hypertension
Keywords: Prevalence, Hypertension, Adolescents, Putrajaya, Malaysia
Response to: Stroke and infective endocarditis

Tan YA, Ng KC, Cheo SW, Low QJ, Chia YK

QJM, 2020 07 01;113(7):517-518.
PMID: 32191336 DOI: 10.1093/qjmed/hcaa099