19672 research outputs found
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DFT studies of structural–electronic correlation for the HAT6 discotic liquid crystal columnar stacking
No full textDiscotic liquid crystals (DLC) have shown much promise for 1-D charge transport and relatively high charge mobility due to π-π conjugation of their cores. However, development of DLCs in molecular electronics are hindered by a lack of systematic study of DLCs' molecular conformation and its effect on the electronic properties. This study takes a model DLC molecule, 2, 3, 6, 7, 10, 11-hexahexyloxytriphenylene (HAT6) and calculates the electronic properties as a function of the columnar structural parameters (co-facial distance, twist and lateral slide) from (density functional theory) DFT calculations. The relationship between the structural parameter to band gap, electronic density of state (DOS) and partial DOS, charge population analysis, and electronic density mapping is discussed
GWAS signals revisited using human knockouts
No full textPurpose: Genome-wide association studies (GWAS) have been instrumental to our understanding of the genetic risk determinants of complex traits. A common challenge in GWAS is the interpretation of signals, which are usually attributed to the genes closest to the polymorphic markers that display the strongest statistical association. Naturally occurring complete loss of function (knockout) of these genes in humans can inform GWAS interpretation by unmasking their deficiency state in a clinical context.Methods: We exploited the unique population structure of Saudi Arabia to identify novel knockout events in genes previously highlighted in GWAS using combined autozygome/exome analysis.Results: We report five families with homozygous truncating mutations in genes that had only been linked to human disease through GWAS. The phenotypes observed in the natural knockouts for these genes (TRAF3IP2, FRMD3, RSRC1, BTBD9, and PXDNL) range from consistent with, to unrelated to, the previously reported GWAS phenotype.Conclusion: We expand the role of human knockouts in the medical annotation of the human genome, and show their potential value in informing the interpretation of GWAS of complex traits
A case report of benign transient hyperphosphatasaemia: What can we learn from this?
No full textWe report a case of benign transient hyperphosphatasaemia (BTH) which was noted incidentally when the patient was admitted for acute tonsillitis. Blood result showed alkaline phosphatase (ALP) at admission was markedly elevated with value of 2481 U/L [normal range 34 – 104 U/L]. He had no history or physical findings to suggest liver or bone disease. Various blood and radiographic investigations were performed to determine the cause but results were normal. He was followed-up with repeat blood test and the alkaline phosphatase normalised after 42 days
Metabolomics and 16S rRNA sequencing of human colorectal cancers and adjacent mucosa
No full textColorectal cancer (CRC) is ranked the third most common cancer in human worldwide. However, the exact mechanisms of CRC are not well established. Furthermore, there may be differences between mechanisms of CRC in the Asian and in the Western populations. In the present study, we utilized a liquid chromatography-mass spectrometry (LC-MS) metabolomic approach supported by the 16S rRNA next-generation sequencing to investigate the functional and taxonomical differences between paired tumor and unaffected (normal) surgical biopsy tissues from 17 Malaysian patients. Metabolomic differences associated with steroid biosynthesis, terpenoid biosynthesis and bile metabolism could be attributed to microbiome differences between normal and tumor sites. The relative abundances of Anaerotruncus, Intestinimonas and Oscillibacter displayed significant relationships with both steroid biosynthesis and terpenoid and triterpenoid biosynthesis pathways. Metabolites involved in serotonergic synapse/ tryptophan metabolism (Serotonin and 5-Hydroxy-3-indoleacetic acid [5-HIAA]) were only detected in normal tissue samples. On the other hand, S-Adenosyl-L-homocysteine (SAH), a metabolite involves in methionine metabolism and methylation, was frequently increased in tumor relative to normal tissues. In conclusion, this study suggests that local microbiome dysbiosis may contribute to functional changes at the cancer sites. Results from the current study also contributed to the list of metabolites that are found to differ between normal and tumor sites in CRC and supported our quest for understanding the mechanisms of carcinogenesis
Tuning of polarization, internal electric field, and hysteresis loop behaviours in BaTiO3/BaxSr1-xTiO3 superlattices
No full textA thermodynamic model based on the Landau-Ginzburg theory is developed to study the polarization and hysteresis loop behaviors in ferroelectric superlattices with technologically important BaxSr1-xTiO3 (BST) solid solutions. Our study shows that the polarization, coercive field, and hysteresis loop behaviors can be tailored by changing the thickness ratio and the Ba/Sr content of BST. The study also found that the sign of the internal fields depends sensitively on both thickness ratio and Ba/Sr content of BST. Both results imply that the internal electric field of superlattice can be tuned to yield zero polarizing or depolarizing field via manipulation of thickness ratio and composition. These findings could pave the way to enhance the efficiency of ferroelectric photovoltaic devices by manipulating the internal electric field through thickness and composition
Economic Burden of the Inadequate Management of Allergic Rhinitis and Urticaria in Asian Countries Based on the GA2LEN Model
No full textPurpose: Across Hong Kong, Malaysia, the Philippines, Singapore, Thailand and Vietnam, (referred to as Asia) approximately 30-53 million individuals of the 151 million employed suffer from allergic rhinitis (AR) and urticaria. It is estimated that approximately 90% of patients with these allergic conditions are insufficiently treated, impacting the socioeconomic burden in terms of absence from work and decreased productivity. This study aims to estimate the socioeconomic burden of allergies in Asia and the cost savings that their adequate management can provide. Due to the limited availability of regional data, this study focused AR and urticaria in selected countries. Methods: Published literature, information from statistical bureaus, clinician surveys and extrapolation of selected data from the European Union were used to determine the socioeconomic costs of AR and urticaria. Results: Many patients in Asia suffer from perennial allergies and experience symptoms of AR and urticaria for up to 298 days per year. An estimate of the indirect costs of patients insufficiently treated for AR and urticaria amounts to USD 105.4 billion a year, which equates to USD 1,137-2,195 per patient due to absenteeism and presenteeism. Adherence to guideline-approved treatment can lead to estimated savings of up to USD 104 billion. Conclusions: The current study suggests that within Asia, the socioeconomic impact of AR and urticaria is similar to that seen in the European Union in spite of the lower wages in Asia. This is due to the mainly perennial allergens prevailing in Asia, whereas the sensitization patterns observed in the European Union are dominated by seasonal exposure to pollen. These results underline the need for governmental initiatives to increase public awareness on the prevention and treatment of these and other allergic diseases as well as greater research funding and large-scale studies to reduce their growing socioeconomic burden in coming years
Effect of Social Media on Child Obesity: Application of Structural Equation Modeling with the Taguchi Method
No full textThrough public health studies, specifically on child obesity modeling, research scholars have been attempting to identify the factors affecting obesity using suitable statistical techniques. In recent years, regression, structural equation modeling (SEM) and partial least squares (PLS) regression have been the most widely employed statistical modeling techniques in public health studies. The main objective of this study to apply the Taguchi method to introduce a new pattern rather than a model for analyzing the body mass index (BMI) of children as a representative of childhood obesity levels mainly related to social media use. The data analysis includes two main parts. The first part entails selecting significant indicators for the proposed framework by applying SEM for primary and high school students separately. The second part introduces the Taguchi method as a realistic and reliable approach to exploring which combination of significant variables leads to high obesity levels in children. AMOS software (IBM, Armonk, NY, USA) was applied in the first part of data analysis and MINITAB software (Minitab Inc., State College, PA, USA) was utilized for the Taguchi experimental analysis (second data analysis part). This study will help research scholars view the data and a pattern rather than a model, as a combination of different factor levels for target factor optimization
Nematode control failure due to anthelmintic resistance in a sheep farm in Malaysia: First identification of the f200y mutation in the isotype 1 β-tubulin gene
No full textThis paper reports total nematode anthelmintic resistance towards albendazole, fenbendazole, levamisole and ivermectin in a commercial sheep farm located in Terengganu, Malaysia. Faecal Egg Count Reduction Test (FECRT) was conducted on 25 sheep, where five sheep in each group were treated with the respective four anthelmintics based on live bodyweight. The balance of five sheep placed in the control group were not treated with any anthelmintics. At day 13 post-treatment, faecal egg count was conducted and nematode worm egg count reduction percentage was calculated to determine the resistance status towards the respective anthelmintics tested. Results showed that nematodes were resistant to all the anthelmintics tested, namely albendazole, fenbendazole, levamisole and ivermectin with reduction percentage of 87%, 46%, 94% and 68%, respectively. Subsequently, the third stage larvae of Haemonchus contortus and Trichostrongylus colubriformis recovered from post-treatment faecal cultures were subjected to allele-specific polymerase chain reaction (AS-PCR) assay to determine the presence of the benzimidazole resistance gene. This study reports the occurrence of the classical F200Y mutation in the isotype 1 β-tubulin gene, for the first time in Malaysia
Self-adaptive conjugate method for a robust and efficient performance measure approach for reliability-based design optimization
No full textThe advanced mean value and hybrid mean value methods are commonly used to evaluate the probabilistic constraint of reliability-based design optimization (RBDO) problems. These iterative methods can yield unstable solutions to highly nonlinear performance functions. The conjugate gradient analysis (CGA) and modified chaos control (MCC) algorithms have recently been employed to achieve the stabilization of reliability analysis in RBDO problems. However, the CGA and the MCC methods can be inefficient for convex performance functions. In this paper, a self-adaptive conjugate gradient (SCG) method is proposed to improve the efficiency of the minimum performance target point (MPTP) search based on an adaptive conjugate scalar factor for highly nonlinear concave and convex problems. With this aim, the conjugate search direction is adaptively computed using the mean value of the previous performance function with a limited conjugate scalar factor. The efficiency and robustness of the proposed SCG algorithm are compared with those of different reliability methods using five nonlinear concave/convex reliability problems and two mathematical/structural RBDO examples. The results indicate that the SCG method accurately converges after less iterations compared to other existing reliability methods. The SCG method is a robust iterative formula for inverse reliability analysis and RBDO
Green Maintenance for Heritage Buildings: An Appraisal Approach for St Paul’s Church in Melaka, Malaysia
No full textMaintenance is an important conservation activity in ensuring the survival of heritage buildings for future generations. Knowledge and practices in this field have essentially shifted toward the sustainability framework, comprised of economic, societal, and environmental parameters. Regarding the environment, low carbon repair became the main item on the sustainability agenda for heritage buildings, and this case study supports this growing agenda by examining the "Green Maintenance" concept and methodology. The study aims to determine the applicability of Green Maintenance in assessing low carbon repair for laterite stone structures based on their embodied carbon expenditure, focusing on St Paul's Church within the Historical City of Melaka, Malaysia. In addition, this study highlights the nature of the maintenance and common techniques and materials used in laterite stone repairs. The results reveal that the most sustainable repair techniques are influenced by the longevity of the repair and the embodied carbon expenditure, represented by the Environmental Maintenance Impact (EMI) of Green Maintenance modeling. The EMI measures the amount of "true" CO2 emissions in a sample of laterite-stone-repair techniques over the selected maintenance period, which can be calculated through the "cradle-to-site" boundary of the Life Cycle Assessment (LCA). The study also found that the quality of repair (workmanship), material durability, and selection of materials to deal with specific areas of deterioration are other variables to be considered when determining the most sustainable technique