Kertas ini membincangkan kaedah untuk mengurangkan kesan interaksi gelombang elektromagnet dengan kepala manusia menggunakan bahan ferit dan metabahan. Pengukuran pengurangan bagi Kadar Penyerapan Spesifik (SAR) menggunakan bahan ferit dan metabahan telah dilaksana dengan kaedah domain-masa perbezaan-terhingga (FDTD) model Lossy-Drude melalui perisian CST Microwave Studio. Metabahan dibentuk dengan menyusun penyalun cincin terpisah (SRRs) secara berkala. Nilai SAR diukur pada beberapa nilai jarak antara model kepala dengan telefon, kelebaran, ketebalan dan ketinggian bahan ferit dan metabahan. Hasil kajian menunjukkan bahawa nilai SAR1g telah berkurang kepada 1.043 W/kg dengan menggunakan bahan ferit dan 1.161 W/kg dengan menggunakan metabahan. Bagi SAR10g, nilai SAR menurun kepada 0.676 W/kg menggunakan bahan ferit dan 0.737 W/kg dengan menggunakan metabahan. Keputusan bagi nilai SAR dalam kepala manusia dengan kehadiran SRR yang membentuk metabahan telah dianalisis untuk menentusahkan kesan bagi pengurangan SAR ini. Keputusan analisis ini boleh memberikan maklumat yang dapat membantu dalam reka bentuk peralatan komunikasi tanpa wayar bagi mematuhi peraturan keselamatan.
This paper focuses on detecting outliers in the circular data which follow the wrapped normal distribution. We considered four discordance tests based on M, C, D and A statistics. The cut-off points of the four tests were obtained and the performance of the detection procedures was studied via simulations. In general, we showed that the discordance test based on the A statistic outperforms the other tests in all cases. For illustration, the city of Kuantan wind direction data set was considered.
MeSH terms: Biometry; Research; Wind; Models, Statistical; Normal Distribution
The effects of strontium doping on the electrical and magneto-transport properties of magneto resistive La0.7Ca0.28Sr0.02MnO3 at different sintering temperatures have been studied. The samples were prepared by the co-precipitation technique (COP) and sintered at 1120, 1220 and 1320 oC. XRD patterns revealed that the samples have an orthorhombic structure and the diffraction patterns can be indexed with the Pbnm space group. The insulator metal transition, TIM increased linearly from 261 K to 272 K with the increase in sintering temperature. The magnetoresistance (MR) measurements were made in magnetic fields from 0.1 to 1 T at room temperature. The percentage of MR increased with increasing of magnetic field and sintering temperature for all samples. The electrical resistivity data were fitted with several equations in the metallic (ferromagnetic) and insulator (paramagnetic) regime. The density of states at the Fermi level N(EF) and the activation energy (Ea) of electron hopping were estimated by using variable range hopping and small polaron hopping model.
We report here the fabrication of microgaps electrodes on amorphous silicon using low cost techniques such as vacuum deposition and conventional lithography. Amorphous silicon is a low cost material and has desirable properties for semiconductor applications. Microgap electrodes have important applications in power saving devices, electrochemical sensors and dielectric detections of biomolecules. Physical characterization by scanning electron microscopy (SEM) demonstrated such microgap electrodes could be produced with high reproducibility and precision. Preliminary electrical
characterizations showed such structures are able to maintain a good capacitance parameters and constant current supply over a wide ranging differences in voltages. They have also good efficiency of power consumption with high insulation properties.
MeSH terms: Electricity; Electrodes; Maintenance; Microscopy, Electron, Scanning; Semiconductors; Silicon; Vacuum; Reproducibility of Results; Electric Capacitance
The Bowen ratio method was applied to determine dry deposition velocity of SO2 over rice paddy in the tropical climate condition (hot and humid). The meteorological parameters and SO2 concentration required by the method were monitored online during July – December 2007. The deposition velocity was evaluated under the wet and dry climatic conditions. The median values of the velocity in daytime in the wet season were in ranges of 0.24 - 0.41 cm s-1, and 0.42 - 0.77 cms-1 in the dry season. The SO2 dry deposition velocity was found to be very low for all the nighttime measurements and
independent of seasonal variation. A relationship between the deposition velocity and the humidity was seen in which the SO2 velocity inversely increased with the relative humidity. The velocity determined by the Bowen ratio study was compared to Wesely resistance model. The comparative study showed that the SO2 deposition velocity obtained by the resistance model was higher than the Bowen ratio in the wet season (high humidity) but lower in the dry season (low humidity). This indicated the effect of humidity on the deposition velocity under the tropical climatology. The parameterization terms to calculate the SO2 deposition in the resistance model need to be modified for the tropical region.
This study focused on the application of a Dielectric Barrier Discharge (DBD ) unit to produce highly oxidizing ozone molecules for the treatment of drinking water. The samples of water were collected from three different sources, namely tap, stone spout and tube-well in the Kathmandu valley. Various physical, chemical and micro-biological analyses were carried out to both the ozone treated and untreated samples of water for comparison. Our results indicated that ozone does not alter the physical characteristics, namely pH, conductivity and turbidity of water but it has significant effect on the chemical properties such as nitrate concentration, total hardness, calcium hardness, Fe(II) and Fe(III) concentration. It was observed that ozone efficiently precipitates ferrous ion into ferric ion and is effective in the removal of fecal coliform, a key element for various water related health problems in most of the developing countries. It is shown that the treatment with ozone leads to a significant reduction in the number of fecal coliform in the samples of drinking water from tap, stone spout and tube well with p values 0.00182, 0.026 and 5.8 ×10-15, respectively at 0.05 level of significance.
Potassium hydroxide (KOH)-catalyzed reactions were utilized to hydrolyze Jatropha curcas seed oil. In this study, the effect of ethanolic KOH concentration, reaction temperature and reaction time to the free fatty acid (FFA) produced were investigated. D-Optimal Design was employed to study the significance of these factors and optimum conditions for the technique was predicted. The results showed that ethanolic KOH concentration was a significant variable for hydrolysis of J. curcas seed oil. In 18 experimental designs, FFA percentage of hydrolyzed J. curcas seed oil increased from 1.89% to 102.2%. The optimal conditions of response were found at 1.75M of ethanolic KOH, 65 °C and at 2 h reaction time. Fourier Transforms Infrared Spectroscopy (FTIR) spectrum analysis confirmed the concentration of ethanolic KOH i.e. at 1.00, 1.50 dan 1.75 M affect the percentage yields of J. curcas seed oil hydrolysis process.
Hepatic phosphoprotein levels are altered in mouse liver as a manifestation of bacteria, virus or parasite infection. Identification of signaling pathways mediated by these hepatic proteins contribute to the current understanding of the mechanism of pathogenesis in malarial infection. The present study was undertaken to evaluate the changes in hepatic phosphoprotein levels during Plasmodium berghei infection. Our study revealed changes in levels of three hepatic phosphoproteins following P. berghei infection compared to non-infected controls. Peptide fragment sequence analysis using tandem mass spectrometry (MS/MS) showed these hepatic proteins to be homologs to haemoglobin beta (HBB), class
Pi glutathione S-tranferase (GSTPi) and carbonic anhydrase III (CAIII) proteins of Mus musculus species respectively from the NCBInr sequence database. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis predicted the involvement of these proteins in specific pathways in Mus musculus species; GSTPi in glutathione and drug metabolism and CAIII in nitrogen metabolism. This shows that P. berghei infection affects similar signaling pathways as those reported in other pathogenic infections such as that related to GSTPi and CAIII in response to oxidative stress.
Free radicals are results of aerobic activities and can damage cells when present in excess by causing oxidative stress. Antioxidants efficiently quench free radicals to counteract oxidative stress. Carotenoids are antioxidants that have detectable natural colorant which can be measured as indicator of antioxidant level in human. The aim of this study is to investigate possible association of carotenoid antioxidant levels in schizophrenia. A total of 524 patients with schizophrenia from Hospital Bahagia Ulu Kinta, Malaysia and 391 healthy controls were recruited. Subjects’ skin carotenoid levels were measured through a non-invasive approach using Raman spectroscopy. Patients with schizophrenia showed significant (p < 0.01) lower carotenoid level compared to healthy controls. Factors such as gender, age, subtypes, antipsychotic drug treatments, and duration of illness did not differ significantly among patients. It is concluded that patient with schizophrenia have low levels of carotenoid antioxidants and is suggested to experience higher level of oxidative stress compared to healthy individuals.
Onychomycosis is the infection of nail apparatus by dermatophytes, yeasts or non-dermatophyte moulds and is responsible for 50% of all nail disorders. A five year retrospective study was conducted at Universiti Kebangsaan Malaysia to identify the common pathogens responsible for onychomycosis and to describe the epidemiology of the affected patients. A total of 278 abnormal nails were cultured, out of which 231 were positive for fungus. Females constituted 50.2% (n=116) while males 49.8% (n=115). The majority (51.9%, n=120) were between ages 50-69 years. The Malay ethnic group was most commonly affected (44.2%, n=102) followed by Chinese (33.8%, n=78), Indians (18.2%, n=42) and other ethnic groups (3.8%, n=9). The most common fungal element isolated was non-dermatophyte moulds (45.4%, n=105) followed by yeast (34.6%, n=80) and dermatophytes (1.3%, n=3). Aspergillus spp. was the commonest (59.8%,n=81) non-dermatophyte mould, while Candida spp. was the commonest yeast (74.3%, n=89) isolated. In this study, non-dermatophyte moulds are the most common microorganisms implicated to cause onychomysosis. Treatment for non-dermatophyte mould is challenging as the current available antifungal agents are more effective against dermatophytes and yeasts.
A study was conducted in a lowland forest at Pasoh Forest Reserve (FR), Negeri Sembilan, to determine the association between liana communities and its soil properties. Liana species inventory and soil samplings were carried out in 16 plots (40 m × 40 m each) established within the 50 ha permanent plot of Pasoh FR. All lianas with diameter at breast height (dbh) of 1 cm and above were measured, tagged and identified, whilst soil samples were analysed for texture, pH, base cations, available nutrients that include Mg, P and K, and inorganic nitrogen of ammonium-N and nitrate-N. The liana inventory recorded a total of 1628 individuals which comprised of 167 species and 65 genera from 31 families. The most speciose family was Annonaceae which was represented by 33 species, followed by Connaraceae and Leguminosae with 20 species and 19 species, respectively. Density-wise, the Leguminosae recorded the highest density of 41 stems/ha, whilst at species level, Byttneria maingayi (Sterculiaceae) showed the highest density of 25 stems/ha. The most important species based on the highest important value (IVi) was Byttneria maingayi with an IVi of 7.5%. Soils analyses showed that the soil texture was dominated by clay, and the organic matter content was low with mean percentage of 3.98±0.21%. In general, the soils of the study site were acidic, whilst available nutrients were in the range of low to high concentrations. Canonical Correspondence Analysis (CCA) showed a low species-environment correlation with eigenvalues of the first and second axes of 0.178 and 0.154, respectively. Nevertheless, the CCA species ordination diagram shows that several liana species are closely associated with soil factors such as soil pH, inorganic nitrogen and available nutrients of Mg, K and P, thus indicates the role of soil factors in influencing floristic distribution patterns of vegetation communities in the forest habitats.
The small indigenous species namely ailiichthys punctata (Day 1871), Botia lohachata (Chaudhuri 1912), Chanda nama (Hamilton 1822), Laubuca laubuca (Hamilton 1822) and Mystus cavasius (Hamilton 1822) comprise an important component of riverine fisheries of Bangladesh. But the natural populations are decreasing fast due to high fishing pressure as well as environmental degradation. Therefore, data and information is needed to avert the alarming decline and initiate conservation measures for these important fishes of the Jamuna River. This study describes the condition- (Fulton’s and Relative weight) and form-factor (a3.0) of the five threatened fishes from the Jamuna River, a distributary of the Brahmaputra River in northern Bangladesh. A total of 919 specimens from five species in five families used for this study were caught by traditional fishing gear during March 2010 through February 2011. For each individual, the total (TL), fork (FL) and standard (SL) length were measured by digital slide calipers while individual body weight (BW) was measured using a digital balance. The Fulton’s condition factor (KF) showed significant variations (p<0.01) among species, with best performance by B. lohachata (1.49±0.20) followed by C. nama (1.41±0.19), M. cavasius (0.79±0.14), L. laubuca (0.78±0.09) and a. punctata (0.71±0.12). The calculated minimum and maximum relative weight (WR) was 53.14 for C. nama and 167.88 for a. punctata, respectively. However, the estimated relative weight (WR) was close to 100 for
all populations (p>0.05) indicating a balanced habitat with food availability relative to the presence of predators. The calculated minimum and maximum form factor (a3.0) was 0.0062 for a. punctata and 0.0158 for B. lohachata, respectively. To the best of our knowledge, this study presents the first reference on KF, WR and a3.0 factors for these threatened species in Bangladesh. The results would be useful for sustainable management and conservation of the limited stocks in the Brahmaputra River ecosystem.
A faunal survey aimed to document small mammals was conducted at Nature Study Centre of Kuala Atok, Taman Negara Pahang from 16th to 23rd May 2008. This survey was part of the Biodiversity Inventory Programme that was organised by the Department of Wildlife and National Parks (DWNP). On average, ten mist nets, two four-bank harp traps, 100 cage traps and 40 Sherman traps were set for six trapping nights. A total of 79 individuals from three orders, seven families and 23 species were caught in this study. Of the 23 species, three were frugivorous bats, 15 were insectivorous bats, four were rodents and one was treeshrew. Our sampling site was bounded by Pahang River and mainly covered with lowland secondary forest. This is evidence by the highest abundance of Long-tailed Giant Rat (Leopoldamys sabanus) for non-volant small mammals, and Fawn Roundleaf Bat (Hipposideros cervinus) for volant small mammals that are adapted to disturbed habitat. The increasing species cumulative curve for Chiropteran indicates that there may be more species yet to be recorded from this study site compared to rodents and treeshrews. Preliminary analysis on the species similarity between our study site to other survey reports in Peninsular Malaysia, positioned Kuala Atok with Krau Wildlife Reserve and Bukit Fraser Forest Reserve that are located adjacent to our study site. This similarity further indicate the
importance of future survey in Kuala Atok especially for Chiropterans to properly document the species diversity in this site that may be as rich as other well studied area e.g. Krau Wildlife Reserve.
Dwarf bamboo is recognized as a significant determinant of the structure and dynamics in temperate forests. Quantitative relationships between the abundance (density and coverage) of dwarf bamboo, Fargesia nitida, and micro-environments, species diversity on the floor were estimated in an Abies faxoniana pure forest in southwest China. Understory microenvironmental conditions (daily differences temperature and moisture, RPPFD under bamboo layer and ground cover) changed dramatically with the bamboo density. Stepwise multiple regression analyses indicated that abundance of F. nitida was mainly correlated with canopy characteristics and disturbance factors in the A. faxoniana pure forest. All richness indices decreased significantly with the bamboo density and RPPFD under bamboo layer. Importance values (IV) of understory species in different bamboo densities and Detrended canonical correspondence analysis (DCCA) indicated three understory plant groups, resistant to high bamboo abundance (Group A), resistant to intermediate bamboo abundance (Group B) and sensitive to bamboo abundance (Group C). These groups mainly responded to abundance of bamboo and RPPFD under bamboo layer, resulted from the integration of characteristics of bamboo, canopy and topography factors. Different bamboo abundance had different influences on understory species diversity and groups. Dense F. nitida condition (> 10 culms/m2) had significant negative effect and 0-5 bamboo condition had not significant negative effect on understory species diversity in A. faxoniana forest. We suggest the fine-scale analysis on effects of bamboo abundance should be taken account into considering in heterogeneous patches in process of the succession and regeneration of natural forests.
Mild cognitive impairment (MCI) is a common condition among the elderly and is believed to be a precursor to Alzheimer disease. This study aims to detect the prevalence of MCI and factors associated with it. A cross-sectional study was conducted on a group of elderly patients attending various medical clinics in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) in 2010. Only patients aged 60 years and above, literate with no hearing or visual impairments were included. Screening instruments included the Mini Mental State Examination (MMSE) and a questionnaire on
sociodemographic and clinical data. The cut-off points for MMSE for MCI was 21/30 to 28/30. The prevalence rate based on MMSE score for ‘normal’ and MCI were 35.3% and 64.7%, respectively. Most of the 346 patients (33.9%) had only one type of medical illness and on one type of medication. MCI was significantly associated with low educational achievement (p<0.05) and rheumatological diseases (p= 0.05). However, it is not associated with the number of medical illnesses suffered by patients and the number of medications prescribed. This study highlighted that MCI was a common condition among the elderly UKMMC Medical clinic attendees and was significantly associated with their low education level.
The aim of the study was to determine the success factors of oral cancer susceptibility prediction using fuzzy models. Three fuzzy prediction models including fuzzy logic, fuzzy neural network and fuzzy linear regression models were constructed and applied to a Malaysian oral cancer data set for cancer susceptibility prediction. The three models’ prediction performances were evaluated and compared. All the three fuzzy models were found to have 64% prediction accuracies for 1-input and 2-input predictor sets. However, when the number of input predictor set was increased to 3-input and 4-input, both fuzzy neural networks’ and fuzzy linear regression’s prediction accuracies increased to 80%, while fuzzy logic prediction accuracy remains at 64%. Fuzzy linear regression model was found to have the capability of quantifying the relationships between input predictors and the predicted outcomes and also suitable for small sample size. Fuzzy neural network model on the other hand, handles ambiguous relationship between variables well but lacks the ability to describe input-output association. The third model, fuzzy logic, is easy to construct but highly dependent on human expert-input. The outcome of this study is a computer-based prediction tool which can be used in cancer screening programs.
Two-point four step direct implicit block method is presented by applying the simple form of Adams- Moulton method for solving directly the general third order ordinary differential equations (ODEs) using variable step size. This method is implemented to get the solutions of initial value problems (IVPs) at two points simultaneously in a block using four backward steps. The numerical results showed that the performance of the developed method is better in terms of maximum error at all tested tolerances and lesser total number of steps as the tolerances getting smaller compared to the existence direct method.
Cobalt films of thickness 21, 29 and 68 nm were prepared by thermal evaporation with a deposition rate around 0.3 nm/s. Their hysteresis loops from longitudinal and polar magneto-optic Kerr effect (MOKE) magnetometry differed from typical characteristics of uniaxial magnetic anisotropy but still indicated the preference of in-plane anisotropy over perpendicular anisotropy. The longitudinal hysteresis loop of the 68 nm-thick film was decidedly in a transcritical state signified by an enhanced coercive field. Changing the angle (θ) between the 2500 Oe-magnetic field and the current gave rise to the change in electrical resistance (Rθ) of 29 nm-thick film and the plot between Rθ and cos2θ could be linearly
fitted. The changes in resistance due to this anisotropic magnetoresistance (AMR) effect ranged from -0.08 % (θ = 90º) to +0.04 % (θ = 0º).
This project deals with the development of a computer interfacing technique for the study of Hall effect. A stepper motor with resolution of 0.1 mm was used to move a pair of permanent magnet backward and forward against the sample. The General Purpose Interface Bus (GPIB) card together with a digital nanovoltmeter and teslameter using serial port siri RS232, interface were used to measure the potential difference and magnetic field strength, respectively. Hall effect for YBa2Cu3-xTixO7-δ system (x=0.00, 0.01, 0.03 and 0.05) showed positive sign Hall coefficient showing that the material is
a hole type carrier at room temperature. Parameters such as Hall coefficient and charge carrier concentration were also display on the front panel of Lab View programming.
Surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out using a gas phase treatment in a Universal Temperature Program (UTP) reactor by flowing SO3 gas onto the CNTs while being heated at different temperatures. The functionalized nanotubes were characterized using X-ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectroscopy. The amount of oxyen and sulfur containing groups was determined by acid-base titration. The titration results were in good agreement with elemental analysis using x-ray fluorescence. FTIRanalysis showed the presence of oxygen and sulfur containing groups, S=O, C-S, C=O and -COOH. Raman spectroscopy confirmed that oxygen and sulfur containing acidic groups covalently attached to the sidewall of the MWCNTs.