2,970 research outputs found
Playing Tic-Tac-Toe Using Genetic Neural Network with Double Transfer functions
Computational intelligence is a powerful tool for game development. In this paper, an algorithm of playing the game Tic-Tac-Toe with computational intelligence is developed. This algorithm is learned by a Neural Network with Double Transfer functions (NNDTF), which is trained by genetic algorithm (GA). In the NNDTF, the neuron has two transfer functions and exhibits a node-to-node relationship in the hidden layer that enhances the learning ability of the network. A Tic-Tac-Toe game is used to show that the NNDTF provide a better performance than the traditional neural network does
Catalytic microwave pyrolysis of waste engine oil using metallic pyrolysis char
Microwave pyrolysis was performed on waste engine oil pre-mixed with different amounts of metallic-char catalyst produced previously from a similar microwave pyrolysis process. The metallic-char catalyst was first prepared by pretreatment with calcination followed by analyses to determine its various properties. The heating characteristics of the mixture of waste oil and metallic-char during the pyrolysis were investigated, and the catalytic influence of the metallic-char on the yield and characteristics of the pyrolysis products are discussed with emphasis on the composition of oil and gaseous products. The metallic-char, detected to have a porous structure and high surface area (124 m2/g), showed high thermal stability in a N2 atmosphere and it was also found to have phases of metals and metal oxides attached or adsorbed onto the char, representing a potentially suitable catalyst to be used in pyrolysis cracking process. The metallic-char initially acted as an adsorptive-support to adsorb metals, metal oxides and waste oil. Then, the char became a microwave absorbent that absorbed microwave energy and heated up to a high temperature in a short time and it was found to generate arcing and sparks during microwave pyrolysis of the waste oil, resulting in the formation of hot spots (high temperature sites with temperature up to 650 °C) within the reactor under the influence of microwave heating. The presence of this high temperature metallic-char, the amounts of which are likely to increase when increasing amounts of metallic-char were added to the waste oil (5, 10, and 20 wt% of the amount of waste oil added to the reactor), had provided a reducing chemical environment in which the metallic-char acted as an intermediate reductant to reduce the adsorbed metals or metal oxides into metallic states, which then functioned as a catalyst to provide more reaction sites that enhanced the cracking and heterogeneous reactions that occurred during the pyrolysis to convert the waste oil to produce higher yields of light hydrocarbons, H2 and CO gases in the pyrolysis products, recording a yield of up to 74 wt% of light C5–C10 hydrocarbons and 42 vol% of H2 and CO gases. The catalytic microwave pyrolysis produced 65–85 wt% yield of pyrolysis-oil containing C5–C20 hydrocarbons that can potentially be upgraded to produce transport-grade fuels. In addition, the recovered pyrolysis-gases (up to 33 wt%) were dominated by aliphatic hydrocarbons (up to 78 vol% of C1–C6 hydrocarbons) and significant amounts of valuable syngas (up to 42 vol% of H2 and CO in total) with low heating values (LHV) ranging from 4.7 to 5.5 MJ/m3, indicating that the pyrolysis-gases could also be used as a gaseous fuel or upgraded to produce more hydrogen as a second-generation fuel. The results indicate that the metallic-char shows advantages for use as a catalyst in microwave pyrolysis treatment of problematic waste oils.
[Graphical abstract - see article]The authors acknowledges the financial support by the Ministry of Science, Technology, and Innovation Malaysia (MOSTI), Ministry of Higher Education Malaysia (MOHE), and University Malaysia Terengganu for the conduct of the research under the E-Science fund (UMT/RMC/SF/13/52072(5), Vot No: 52072), the Fundamental Research Grant Scheme (Project No: FRGS/1/2013/TK05/UMT/02/2, Vot No: 59296), and the Research Acculturation Grant Scheme (Project No: RAGS/2012/UMT/TK07/3, Vot No: 57085).This is the author accepted manuscript. The final version is available from [publisher] via http://dx.doi.org/10.1016/j.apcatb.2015.04.01
Group sequencing around a common due date
Author name used in this publication: C. T. Ng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Elucidating the relationship between crystallo-chemistry and optical properties of CIGS nanocrystals
The performance of solar cells fabricated using Cu(In,Ga)(S,Se)2 nanocrystal (NC) inks synthesized using the hot injection method has yielded efficiencies up to 12% recently. The efficiency of these devices is highly dependent on the chemical composition and crystallographic quality of the NCs. The former has been extensively discussed as it can be easily correlated to the optical properties of the film, but detailed crystallographic structure of these NCs has scarcely been discussed and it can influence both the optical and electrical properties. Hence both chemical composition and crystal structure should be explored for these NCs in order for this material to be further developed for application in thin film solar cells. In this work, a thorough investigation of the composition and crystal structure of CuIn x Ga1−x Se2 NCs synthesized using the hot injection method over the entire composition range (0 ≤ x ≤ 1) has been conducted. Raman spectroscopy of the NCs complements the information derived from x-ray diffraction (XRD) and electron probe microanalysis (EPMA). EPMA, which was carried out for the first time, indicates good controllability of the NC Ga/(In + Ga) ratio using this synthesis method. Raman spectroscopy reveals that CuInSe2 NCs are a mixture of chalcopyrite and sphalerite with disordered cations, whereas CuGaSe2 NCs are purely chalcopyrite. The lattice parameters determined from XRD were found to deviate from those calculated using Vegard's law for all compositions. Hence, it can be deduced that the lattice is distorted in the crystal. The optical and electrochemical band gap of CuIn x Ga1−x Se2 NCs increases as the Ga content increases. The energy band gap deviates from the theoretical values, which could be related to the contribution from cation disordering and strain. These results help to tailor the opto-electrical properties of semiconductors, which inherently depend on the crystalline quality, strain and composition
Gamma-glutamyl transferase level predicts the development of hypertension in Hong Kong Chinese
Introduction: Liver enzymes are elevated in cardiometabolic diseases, particularly when there is non-alcoholic fatty
liver disease. We therefore investigated if hypertension is associated with elevated levels of alkaline phosphatase (ALP),
alanine aminotransferase (ALT), aspartate aminotransferase and γ-glutamyl transferase (GGT).
Methods: We included 235 hypertensive and 708 normotensive subjects from the Hong Kong Cardiovascular Risk
Factor Prevalence Study-2 (CRISPS-2) in 2000-2004 who had fewer than one alcoholic drink a week. In the follow-up
study in 2005-2008 (CRISPS-3), 126 out of the 708 subjects had developed hypertension.
Results: In CRISPS-2, plasma ALT (OR=1.31 per SD of log-transformed level, P=0.005) and GGT (OR=1.52 per SD
of log-transformed level, P<0.001) were significantly associated with prevalent hypertension after adjusting for age,
sex and body mass index (BMI). Among subjects not on anti-hypertensive medication, plasma ALP and GGT were
significantly associated with both systolic blood pressure (beta=0.141, P<0.001 for ALP and beta=0.096, P=0.004
for GGT) and diastolic blood pressure (beta=0.131, P<0.001 for ALP and beta=0.102, P=0.004 for GGT). In forward
stepwise logistic regression analysis of subjects normotensive at CRISPS-2, the highest tertile of plasma GGT level
was an independent predictor of the development of hypertension in CRISPS-3 (OR=2.40, P=0.010), together with
age, BMI, systolic blood pressure and plasma CRP at baseline, and change in BMI. The other liver enzymes were not
significantly predictors of new-onset hypertension.
Conclusions: Among the four liver enzymes, elevated GGT level is the strongest risk factor for hypertension in Hong
Kong Chinese.
Acknowledgement: This study was funded by Hong Kong Research Grant Council grants (HKU7229/01M and HKU7626/07M)
and the Sun Chieh Yeh Heart Foundation.published_or_final_versio
Role of genetic variants in gene encoding lipocalin-2 in the development of elevated blood pressure
Introduction: Lipocalin-2 is recently recognised as a biomarker of obesity and inflammation, which are both risk
factors for hypertension. We therefore investigated the association of common single nucleotide polymorphisms (SNPs)
in the gene encoding lipocalin-2 (LCN2) with elevated blood pressure in Hong Kong Chinese.
Methods: Five tagging SNPs were genotyped in 1936 subjects from the Hong Kong Cardiovascular Risk Factor
Prevalence Study-2 (CRISPS-2) with a median follow-up period of 6.4 years. Elevated blood pressure was defined as
≥130/85 mm Hg or taking anti-hypertensive medication.
Results: There were only two haplotypes with frequency of >5%, namely AGATC (45.5%) and GGTCC (41.2%).
Haplotype GGTCC was associated with elevated blood pressure at follow-up (OR=1.17 compared to haplotype
AGATC, P=0.031 after adjusting for age and sex). Among 1381 subjects without elevated blood pressure at baseline,
321 subjects developed elevated blood pressure at follow-up. Haplotype GGTCC was associated with the development
of elevated blood pressure at follow-up (OR=1.30 compared to haplotype AGATC, P=0.011 after adjusting for age,
sex, systolic blood pressure, and follow-up duration; OR=1.44, P=0.0015 after further adjusting for other covariates).
Among subjects not taking anti-hypertensive medication, carriers of the haplotype GGTCC had higher systolic blood
pressure than non-carriers (119.7±16.4 mm Hg vs 117.9±17.3 mm Hg, P=0.043).
Conclusion: Our findings suggest, for the first time, that genetic variants in LCN2 may affect blood pressure. Further
studies on the role of lipocalin-2 in blood pressure regulation are warranted.
Acknowledgement: This study was funded by Hong Kong Research Grant Council grants (HKU7229/01M and HKU7626/07M)
and the Sun Chieh Yeh Heart Foundation.published_or_final_versio
Gamma-glutamyl transferase level predicts the development of hypertension in Hong Kong Chinese
Background: Plasma activities of alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase, and γ-glutamyl transferase (GGT) are often increased in cardiometabolic diseases. We investigated if hypertension is associated with increased activities of these plasma markers. Methods: We included 235 hypertensive and 708 normotensive subjects (mean age 47.3 ± 9.6 and 58.0 ± 10.2. years respectively) from the Hong Kong Cardiovascular Risk Factor Prevalence Study-2 (CRISPS-2) in 2000-2004 who had drank < 1/week. In the follow-up study in 2005-2008 (CRISPS-3), 126 out of the 708 subjects had developed hypertension. Results: Raised plasma ALT (OR = 1.22 per SD of log-transformed level, P=0.045) and GGT (OR = 1.38 per SD of log-transformed level, P=0.001) levels were associated with hypertension at baseline in CRISPS-2 after adjusting for covariates. Among subjects not on anti-hypertensive medications, plasma ALP, ALT and GGT were related to blood pressure (P< 0.01). In subjects normotensive at CRISPS-2, plasma GGT, but not ALP, ALT and AST, was an independent predictor of new-onset hypertension at CRISPS-3 (OR = 1.38 per SD of log-transformed level, P=0.020 and OR = 2.68 for 3rd tertile vs. 1st tertile, P=0.004) after adjusting for covariates. Conclusions: Among the 4 plasma markers, increased GGT activity is the strongest predictor for existing and new-onset hypertension in Hong Kong Chinese. © 2011 Elsevier B.V.postprin
Association of a genetic variant in adrenomedullin gene with its plasma level
published_or_final_versionThe 16th Annual Research Conference of the Department of Medicine, The University of Hong Kong, Hong Kong, 22 January 2011. In Hong Kong Medical Journal, 2011, v. 17, suppl. 1, p. 19, abstract no. 1
Hong Kong Chinese community leaders' perspectives on family health, happiness and harmony: A qualitative study
This paper examines the views of Hong Kong community leaders on the underlying issues that affect family health, happiness and harmony (3Hs) in Hong Kong. Using a community reconnaissance method, a series of individual in-depth interviews with 26 leaders that represent neighbourhoods of diverse socio-economic status (SES) from June to August 2008 were conducted. Participants considered that changing family structure, economic situation and strong work ethic are the most salient factors that affect family 3Hs. The deprived comprehensive social security assistance recipients, single-parent families and migrant women were considered to be the most vulnerable groups to breakdown in family 3Hs and particularly, they lack family resources. Families from different SES have to overcome different challenges in order to achieve and sustain family 3Hs. Leaders from low SES neighbourhood were concerned more about providing tangible help such as child care facilities to improve family resources, whereas leaders from high SES neighbourhood focused more on preventive interventions such as education on relationship skills to achieve better family well-being. The findings offer insights in designing effective social marketing education campaigns and family-friendly workplace policy to promote social harmony through the maintenance of 3Hs families. © The Author 2011. Published by Oxford University Press. All rights reserved.postprin
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