Showing papers by "National University of Malaysia published in 2004"

The Classification of Glomerulonephritis in Systemic Lupus Erythematosus Revisited

Abstract: The currently used classification reflects our understanding of the pathogenesis of the various forms of lupus nephritis, but clinicopathologic studies have revealed the need for improved categorization and terminology. Based on the 1982 classification published under the auspices of the World Health Organization (WHO) and subsequent clinicopathologic data, we propose that class I and II be used for purely mesangial involvement (I, mesangial immune deposits without mesangial hypercellularity; II, mesangial immune deposits with mesangial hypercellularity); class III for focal glomerulonephritis (involving or = 50% of total number of glomeruli) either with segmental (class IV-S) or global (class IV-G) involvement, and also with subdivisions for active and sclerotic lesions; class V for membranous lupus nephritis; and class VI for advanced sclerosing lesions]. Combinations of membranous and proliferative glomerulonephritis (i.e., class III and V or class IV and V) should be reported individually in the diagnostic line. The diagnosis should also include entries for any concomitant vascular or tubulointerstitial lesions. One of the main advantages of the current revised classification is that it provides a clear and unequivocal description of the various lesions and classes of lupus nephritis, allowing a better standardization and lending a basis for further clinicopathologic studies. We hope that this revision, which evolved under the auspices of the International Society of Nephrology and the Renal Pathology Society, will contribute to further advancement of the WHO classification.

Effects of performance appraisal politics on job satisfaction and turnover intention

Abstract: There is evidence that performance ratings are often manipulated for political purposes. The present study examined the effects of employees' perceptions of political motives in performance appraisal on their job satisfaction and intention to quit using survey data from an occupationally heterogeneous sample of white‐collar employees (N=127) from various organizations. Regression analysis results indicated that when employees perceived performance ratings to be manipulated because of raters' personal bias and intent to punish subordinates they expressed reduced job satisfaction that, in turn, led to greater intentions to quit their jobs. Manipulations of ratings for motivational purposes, however, had no effect on job satisfaction and turnover intention.

A new family of optical code sequences for spectral-amplitude-coding optical CDMA systems

Abstract: A new code structure for spectral-amplitude-coding optical code-division multiple-access system based on double-weight (DW) code families is proposed. The DW code has a fixed weight of two. By using a mapping technique, codes that have a larger number of weights can be developed. Modified double-weight (MDW) code is a DW code family variation that has variable weights of greater than two. The newly proposed code possesses ideal cross-correlation properties and exists for every natural number n. Based on theoretical analysis and simulation, MDW code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.

Nipah Virus: Vaccination and Passive Protection Studies in a Hamster Model

Abstract: Nipah virus, a member of the paramyxovirus family, was first isolated and identified in 1999 when the virus crossed the species barrier from fruit bats to pigs and then infected humans, inducing an encephalitis with up to 40% mortality. At present there is no prophylaxis for Nipah virus. We investigated the possibility of vaccination and passive transfer of antibodies as interventions against this disease. We show that both of the Nipah virus glycoproteins (G and F) when expressed as vaccinia virus recombinants induced an immune response in hamsters which protected against a lethal challenge by Nipah virus. Similarly, passive transfer of antibody induced by either of the glycoproteins protected the animals. In both the active and passive immunization studies, however, the challenge virus was capable of hyperimmunizing the vaccinated animals, suggesting that although the virus replicates under these conditions, the immune system can eventually control the infection.

Career commitment and career success: moderating role of emotion perception

Abstract: This study examined the moderating effect of emotion perception – a basic component of emotional intelligence – on the relationship between career commitment and career success. White‐collar employees from a diverse set of occupations and organizations in Malaysia were surveyed. Moderated multiple regression results showed that career commitment predicted objective career success (i.e. salary level) only for employees with average to high emotion perception but not for those with low emotion perception. Emotion perception, however, did not moderate the effects of career commitment on subjective career success (i.e. career satisfaction). Implications of the findings and suggestions for future research are discussed.

Environmental values and resource management options: a choice modelling experience in malaysia

Abstract: The management of the Matang Mangrove Wetlands in Perak State, Malaysia is under review. To assist decision makers in determining the optimal management strategy, a choice modelling application was undertaken to estimate the non-market values provided under different management options. Implicit prices for environmental attributes including the area of environmental forest protected, the number of bird species protected and the recreation use of the area were estimated. In addition, the implicit price of a social, non-market attribute, the employment of local people in wetland based extractive industries, was estimated. Compensating surplus estimates for a number of alternative wetland management scenarios were also calculated.

Mitochondrial DNA sequences reveal the photosynthetic relatives of Rafflesia, the world's largest flower

Abstract: All parasites are thought to have evolved from free-living ancestors. However, the ancestral conditions facilitating the shift to parasitism are unclear, particularly in plants because the phylogenetic position of many parasites is unknown. This is especially true for Rafflesia, an endophytic holoparasite that produces the largest flowers in the world and has defied confident phylogenetic placement since its discovery >180 years ago. Here we present results of a phylogenetic analysis of 95 species of seed plants designed to infer the position of Rafflesia in an evolutionary context using the mitochondrial gene matR (1,806 aligned base pairs). Overall, the estimated phylogenetic tree is highly congruent with independent analyses and provides a strongly supported placement of Rafflesia with the order Malpighiales, which includes poinsettias, violets, and passionflowers. Furthermore, the phylogenetic placement of Mitrastema, another enigmatic, holoparasitic angiosperm with the order Ericales (which includes blueberries and persimmons), was obtained with these data. Although traditionally classified together, Rafflesia and Mitrastema are only distantly related, implying that their endoparasitic habits result from convergent evolution. Our results indicate that the previous significant difficulties associated with phylogenetic placement of holoparasitic plants may be overcome by using mitochondrial DNA so that a broader understanding of the origins and evolution of parasitism may emerge.

Isolation and molecular identification of Nipah virus from pigs

Abstract: Nipah viruses from pigs from a Malaysian 1998 outbreak were isolated and sequenced. At least two different Nipah virus strains, including a previously unreported strain, were identified. The findings highlight the possibility that the Malaysia outbreaks had two origins of Nipah virus infections.

Vitamin D status among postmenopausal Malaysian women.

Abstract: Serum levels of 25-hydroxyvitamin D (25 (OH) D) were determined in 276 (103 Malays and 173 Chinese) postmenopausal women, aged 50 to 65 years. The level of 25 (OH) D was significantly lower in the postmenopausal Malay women (44.4 +/-10.6 nmol/L) compared to the Chinese women (68.8 +/- 15.7 nmol/L) (P<0.05). There were 27% Malay women with serum 25 (OH) D in the range of 50 - 100 nmol/L (defined as lowered vitamin D status, or hypovitaminosis D) and 71% with levels in the range of 25 - 50 nmol/L (defined as vitamin D insufficiency) compared to 87% and 11% Chinese women respectively. Serum 25 (OH) D was found to significantly correlate with BMI, fat mass and PTH level. Multivariate analyses showed that race has a strong association with vitamin D status. The high prevalence of inadequate levels of serum vitamin D found in our study may have important public health consequences and warrants the development of a strategy to correct this problem in the older adult Malaysian population.

Cement-based solidification for the safe disposal of blasted copper slag

Abstract: This paper describes an investigation of cement-based solidification/stabilization process for the safe disposal of blasted copper slag. The treatments evaluated were based on ordinary Portland cement (OPC). Mortar specimens with ground copper slag ranging from 0% to 10% by weight of cement were tested for whole block and crushed block leachability, compressive strength and hydration. The results indicated that the leaching of selected heavy metal ions from the cement matrix was low and did not exceed the Malaysian Environmental Quality Act. Addition of copper slag to cement increased initial and final setting times. The primary hydration process was the OPC hydration. The strength of the copper slag mortar was generally lower than that of the control mortar and the amount of ground copper slag to replace cement for optimum strength was about 5%.

Genetic diversity of oil palm (Elaeis guineensis Jacq.) germplasm collections from Africa: implications for improvement and conservation of genetic resources

Abstract: A total of 723 accessions of oil palm ( Elaeis guineensis Jacq.) from 26 populations representing ten countries in Africa and one Deli dura family were screened for allelic variation at seven enzyme loci from six enzyme systems using starch gel electrophoresis. On average, 54.5% of the loci were polymorphic (0.99 criterion). The average and effective number of alleles per locus was 1.80 and 1.35, respectively. Mean expected heterozygosity was 0.184, with values ranging from 0.109 (population 8, Senegal) to 0.261 (population 29, Cameroon). The genetic differentiation among populations was high (F(ST)=0.301), indicating high genetic divergence. The calculation of F(ST) by geographic zones revealed that the high F(ST) was largely due to F(ST) among populations in West Africa, suggesting diversifying selection in this region. The mean genetic distance across populations was 0.113. The lowest genetic distance (D) was observed between population 5 from Tanzania and population 7 from the Democratic Republic of the Congo (0.000) and the highest was found between population 4 from Madagascar and population 13 from Sierra Leone (0.568). The total gene flow across oil palm populations was low, with an Nm of 0.576, enhancing genetic structuring, as evident from the high F(ST) values. UPGMA cluster analysis revealed three main clusters; the western outlying populations from Senegal and Sierra Leone were in one cluster but separated into two distinct sub-clusters; the eastern outlying populations from Madagascar were in one cluster; the populations from Angola, Cameroon, The Democratic Republic of the Congo, Ghana, Tanzania, Nigeria and Guinea were in one cluster. The Deli dura family seems to be closely related to population 6 from Guinea. Oil palm populations with high genetic diversity-i.e. all of the populations from Nigeria, Cameroon and Sierra Leone, population 6 of Guinea, population 1 of Madagascar and population 2 of Senegal should be used in improvement programmes, whereas for conservation purposes, oil palm populations with high allelic diversity (A(e)), which include populations 22 and 29 from Cameroon, populations 39 and 45 from Nigeria, population 6 from Guinea, populations 5 and 13 from Sierra Leone and population 1 from Madagascar should be selected for capturing as much genetic variation as possible.

Weed problems and their management in rice fields of Malaysia: An overview

Abstract: The available literature on weed problems and weed control in rice fields in Malaysia is reviewed and suggestions for future research are included. The problem of weed competition with rice is of great economic importance in the country because it causes a 10–35% reduction in grain yield. About US$4.10 million is spent annually on herbicides for rice alone, and this amounts to approximately 7% of the total expenditure on herbicides. The shift in methods of rice culture from transplanting to direct seeding has magnified the weed problem. The problem of weedy rice is particularly acute in the direct-seeding rice areas. Although a number of sulfonylurea herbicides (e.g. cinosulfuron, metsulfuron, bensulfuron and pyrazosulfuron) have been found to be suitable alternatives to the old herbicide 2,4-D, an integrated weed management program must be developed in order to reduce the problem of herbicide resistance in weeds. Weed control methods that are more friendly to the environment and affordable to farmers must be sought. Weed-competitive and allelopathic rice varieties must be produced. The problem of weeds in rice calls for systematic studies on biotechnological methods of control of weedy rice. Detailed studies on the biology and ecology of notorious rice weeds, particularly Oryza sativa L. (weedy rice), Echinochloa spp., Leptochloa chinensis (L.) Nees, Fimbristylis miliacea (L.) Vahl. and Limnocharis flava (L.) Buch. need to be done in order to formulate successful weed control measures.

Implementation of inverse perspective mapping algorithm for the development of an automatic lane tracking system

Abstract: Vision based automatic lane tracking system requires information such as lane markings, road curvature and leading vehicle be detected before capturing the next image frame. Placing a camera on the vehicle dashboard and capturing the forward view results in a perspective view of the road image. The perspective view of the captured image somehow distorts the actual shape of the road, which involves the width, height, and depth. Respectively, these parameters represent the x, y and z components. As such, the image needs to go through a pre-processing stage to remedy the distortion using a transformation technique known as an inverse perspective mapping (IPM). This paper outlines the procedures involved.