National University of Malaysia

About: National University of Malaysia is a education organization based out in Kuala Lumpur, Malaysia. It is known for research contribution in the topics: Population & Heat transfer. The organization has 26593 authors who have published 41270 publications receiving 552683 citations. The organization is also known as: NUM & Universiti Kebangsaan Malaysia.

The Prognostic Value of the Glasgow Coma Scale, Hypoxia and Computerised Tomography in Outcome Prediction of Pediatric Head Injury

Abstract: The outcome of 151 children less than 15 years of age and admitted within 24 h of head injury was studied in relation to clinical and computed tomography (CT) scan features. Thirty one (20.5%) had a p

Wheat mitochondrial respiration shifts from the tricarboxylic acid cycle to the GABA shunt under salt stress

Abstract: Mitochondrial respiration and tricarboxylic acid (TCA) cycle activity are required during salt stress in plants to provide ATP and reductants for adaptive processes such as ion exclusion, compatible solute synthesis and reactive oxygen species (ROS) detoxification. However, there is a poor mechanistic understanding of how salinity affects mitochondrial metabolism, particularly respiratory substrate source. To determine the mechanism of respiratory changes under salt stress in wheat leaves, we conducted an integrated analysis of metabolite content, respiratory rate and targeted protein abundance measurements. Also, we investigated the direct effect of salt on mitochondrial enzyme activities. Salt-treated wheat leaves exhibit higher respiration rate and extensive metabolite changes. The activity of the TCA cycle enzymes pyruvate dehydrogenase complex and the 2-oxoglutarate dehydrogenase complex were shown to be directly salt-sensitive. Multiple lines of evidence showed that the γ-aminobutyric acid (GABA) shunt was activated under salt treatment. During salt exposure, key metabolic enzymes required for the cyclic operation of the TCA cycle are physiochemically inhibited by salt. This inhibition is overcome by increased GABA shunt activity, which provides an alternative carbon source for mitochondria that bypasses salt-sensitive enzymes, to facilitate the increased respiration of wheat leaves.

Cell wall modifications, degrading enzymes and softening of carambola fruit during ripening

Abstract: The fruit extracts of the slow-ripening cv. B 10 carambola (Averrhoa carambola L.) contained a number of cell wall hydrolases. The predominant ones appeared to be β-(1,4)-glucanase (as carboxymethylcellulase), pectinesterase, β-galactosidase, and polygalacturonase (PG). Other significant hydrolases the activity of which also increased with ripening were the glycosidases,α-arabinosidase, α-galactosidase, and α-mannosidase, and also the glycanases, β-(1,4)-galactanase and xylanase. Throughout ripening, as pectins and hemicelluloses were being differentially modified, the levels of buffered-phenol cell wall materials, total polyuronides as well as arabinose, galactose, xylose, and glucose decreased. At early ripening phase (days 0-12) there was no apparent pectin solubilization, and the loosely-bound water- and chelator-soluble pectins were the first pectic polysaccharides to be affected. That of the former exhibited an upshift, whilst the latter, showed a distinct downshift in their molecular size profiles. At late ripening phase (days 12-24) when tissue firmness had declined substantially, dramatic changes involving pectins and hemicelluloses were evident. Pectins were solubilized, and this increased solubility was accompanied by depolymerization of all pectin classes and a decrease in the level of the Na 2 CO 3 -soluble polyuronides. Coincident with this marked modifications of the tightly-bound, predominant polyuronide fractions and hemicellulose was the increase in activities of polygalacturonase and β-(1,4)-glucanase, suggesting that these enzymes may contribute to wall modifications late during ripening. Some of the other wall hydrolases, namely, α-arabinosidase, α-galactosidase and certain isoforms of β-galactosidase/galactanase, might be relevant to the early ripening changes when pectin solubilization was limited.

Digital game-based learning (DGBL) model and development methodology for teaching history

Abstract: History subject plays a vital role in instilling the spirits of patriotism among the students; to nourish and instill love and loyalty to one's country and to be a true citizen. The lack of creativity in history teaching caused process effectively and interestingly especially among young learners. Digital Game Based Learning (DGBL) approach utilizes the game as a medium for conveying learning contents. There are many models for educational games development which combined the Instructional Design (ID) and game development process. However, there is still a conflict on how to merge ID and game development effectively. Therefore, we looked into the pedagogy and game design aspects. We then propose a DGBL model for History educational games design and a development methodology which combined the ID and game development process, named DGBL-ID model. The DGBL-ID model consists of five phases: analysis, design, development, quality assurance as well as implementation and evaluation.

Seasonal variability of PM 2.5 composition and sources in the Klang Valley urban-industrial environment

Abstract: . This study investigates the fine particulate matter (PM2.5) variability in the Klang Valley urban-industrial environment. In total, 94 daily PM2.5 samples were collected during a 1-year campaign from August 2011 to July 2012. This is the first paper on PM2.5 mass, chemical composition and sources in the tropical environment of Southeast Asia, covering all four seasons (distinguished by the wind flow patterns) including haze events. The samples were analysed for various inorganic components and black carbon (BC). The chemical compositions were statistically analysed and the temporal aerosol pattern (seasonal) was characterised using descriptive analysis, correlation matrices, enrichment factor (EF), stoichiometric analysis and chemical mass closure (CMC). For source apportionment purposes, a combination of positive matrix factorisation (PMF) and multi-linear regression (MLR) was employed. Further, meteorological–gaseous parameters were incorporated into each analysis for improved assessment. In addition, secondary data of total suspended particulate (TSP) and coarse particulate matter (PM10) sampled at the same location and time with this study (collected by Malaysian Meteorological Department) were used for PM ratio assessment. The results showed that PM2.5 mass averaged at 28 ± 18 µg m−3, 2.8-fold higher than the World Health Organisation (WHO) annual guideline. On a daily basis, the PM2.5 mass ranged between 6 and 118 µg m−3 with the daily WHO guideline exceeded 43 % of the time. The north-east (NE) monsoon was the only season with less than 50 % sample exceedance of the daily WHO guideline. On an annual scale, PM2.5 mass correlated positively with temperature (T) and wind speed (WS) but negatively with relative humidity (RH). With the exception of NOx, the gases analysed (CO, NO2, NO and SO2) were found to significantly influence the PM2.5 mass. Seasonal variability unexpectedly showed that rainfall, WS and wind direction (WD) did not significantly correlate with PM2.5 mass. Further analysis on the PM2.5 ∕ PM10, PM2.5 ∕ TSP and PM10 ∕ TSP ratios reveal that meteorological parameters only greatly influenced the coarse particles (particles with an aerodynamic diameter of greater than 2.5 µm) and less so the fine particles at the site. Chemical composition showed that both primary and secondary pollutants of PM2.5 are equally important, albeit with seasonal variability. The CMC components identified were in the decreasing order of (mass contribution) BC > secondary inorganic aerosols (SIA) > dust > trace elements > sea salt > K+. The EF analysis distinguished two groups of trace elements: those with anthropogenic sources (Pb, Se, Zn, Cd, As, Bi, Ba, Cu, Rb, V and Ni) and those with a crustal source (Sr, Mn, Co and Li). The five identified factors resulting from PMF 5.0 were (1) combustion of engine oil, (2) mineral dust, (3) mixed SIA and biomass burning, (4) mixed traffic and industrial and (5) sea salt. Each of these sources had an annual mean contribution of 17, 14, 42, 10 and 17 % respectively. The dominance of each identified source largely varied with changing season and a few factors were in agreement with the CMC, EF and stoichiometric analysis, accordingly. In relation to meteorological–gaseous parameters, PM2.5 sources were influenced by different parameters during different seasons. In addition, two air pollution episodes (HAZE) revealed the influence of local and/or regional sources. Overall, our study clearly suggests that the chemical constituents and sources of PM2.5 were greatly influenced and characterised by meteorological and gaseous parameters which vary greatly with season.