Browse publications by year: 2007

  1. Leong KC, Teng CL
    Aust Fam Physician, 2007 Sep;36(9):679; author reply 680.
    PMID: 17918303
    Comment on: Cannon B, Usherwood TP. General practice consultations - how well do doctors
    predict patient satisfaction? Aust Fam Physician. 2007 Mar;36(3):185-6, 192. PubMed PMID: 17339988.
    MeSH terms: Attitude of Health Personnel; Family Practice/standards*; Humans; Physician-Patient Relations*; Physicians, Family/psychology*; Time Factors; Patient Satisfaction*; Health Care Surveys
  2. Kim SL, Wickneswari R, Chee YC
    Sains Malaysiana, 2007;36:233-242.
    The disturbance level of two nearby logged stands, Compartment 118 and Compartment 69 were studied in Ulu Sedili Forest Reserve, Johor. The mean basal area for trees (trees ³ 1 cm dbh) in logged stand of Compartment 118 showed 51% reduction in comparison to immediately before logging of the same stand. A similar level of reduction (47%) was observed for mean density of trees in Compartment 118. However, the mean basal area and mean density of tree were higher in 50-year logged Compartment 69 (21% and 122% respectively) compared to Compartment 118 before logging. Concurrently, we examined the effects of logging on genetic diversity of seedling, sapling and mature trees of two important timber species, Koompassia malaccensis and Dryobalanops aromatica using M13 universal primer (multilocus minisatellite DNA) and three other universally-primed primers. Mature trees of K. malaccensis showed 39% reduction in Shannon diversity index (H) in Compartment 69 compared to Compartment 118 before logging detected by M13 universal primer. This may be attributed to the small sample size of the species in Compartment 69. Reduction in H and polymorphic loci (P) for K. malaccensis was higher in seedlings, 5% and 56% respectively in Compartment 69 compared to mature trees (3% and 23% respectively). Contrastingly for seedlings and saplings of D. aromatica, increment in H was higher in Compartment 69 than Compartment 118 immediately after logging, which was 25% and 14% for seedlings while 21% and 14% for saplings, detected by M13 universal primer. The increased genetic diversity detected for this species may be due to its high density in Compartment 118 and Compartment 69. Loss in alleles caused a decline in H of K. malaccensis, especially mature trees in Compartment 69. On the other hand, H of D. aromatica was not affected by loss of alleles.
  3. Darwis S, Isnani, Ashat A
    Sains Malaysiana, 2007;36:207-211.
    The aim of semivariogram modeling is to infer the structure of spatial continuity of the measurements. Practical experiences show that semivariogram modeling is an important step in spatial interpolation. The usual empirical semivariogram is sensitive to extreme data and shows a noised pattern. Some robust empirical semivariogram was proposed. This paper reports the application of pairwise relative empirical semivariogram to Kamojang geothermal decline rate. Using the same data, the usual empirical semivariogram and pairwise semivariogram are compared. Comparative study shows that the empirical pairwise relative semivariogram is able to infer the structure of spatial continuity of the process.
    MeSH terms: Hypersensitivity; Spatial Analysis
  4. Roslinda Shamsudin, Abdul Razak Daud, Muhammad Azmi Abdul Hamid, Saiful Rizam Shamsudin
    Sains Malaysiana, 2007;36:195-200.
    Nitridation behaviour of Al-Mg-Si alloys was studied as a function of temperature by means of thermogravimetry method. A reactive gas, N2-4%H2 at a rate of 10 ml/min was purged into the thermogravimetry analyser chamber. The Al alloys were heated from 25oC to 625oC at the heating rate of 15oC/min and then reduced to 3oC/min until it reached 1500oC. It was found that by varying the amount of Mg and Si in Al-Mg-Si alloys significantly influenced the growth of the composites. A differential thermogravimetric curve shows the Mg containing alloys experienced many steps of chemical reactions. This indicates that besides AlN presence as a major phase, other compounds also exist in the final product. The X-ray diffraction results confirmed the existence of oxide phases such as a-Al2O3, MgAl2O4 and MgO in addition to residual Si and Al metal. The presence of oxide compounds is believed to be due to the reaction between the alloying elements and residual oxygen gas left in the reaction atmosphere. It was also found that Si could play a role in promoting the weight gain of the composite produced. The heating rate has also a profound effect on the weight gain, whereby higher heating rate resulted in low yielded of AlN during the nitridation reaction of the Al-Mg-Si alloys.
    MeSH terms: Alloys; Aluminum Oxide; Hot Temperature; Heating; Magnesium Oxide; Oxides; Oxygen; Temperature; Thermogravimetry; X-Ray Diffraction; Weight Gain
  5. Tangang FT, Mohd Syamil Mohd Yussof, Liew J
    Sains Malaysiana, 2007;36:165-173.
    The current circulation pattern in waters around Pulau Tinggi, Johor was deduced based on the results of the Acoustic Doppler Current Profiler (ADCP) measurements during a period of 16 – 19 August 2004. It appears that the currents, regardless of tidal cycle, were predominantly southerly or southeasterly with average speeds of between 30 – 50 cm s-1. There appears to be current speed horizontal gradient toward the island as the current became weaker as it gets closer to the island. In the upper 10-15 m the currents were slowed by the prevailing winds which were predominantly southeasterly during the period. In the lower layer, about 10 m from seabed, the current speed reduced drastically due to bottom friction. The circulation pattern proves to be a typical pattern of a flow around an island where an evident of an eddy was captured in the observation data in a station located south of the island. Estimated shallow water Reynolds number indicates that the flow may produce a pair vortex of opposite direction and a central return flow at the southern end of the island.
  6. Abdul Rahim Samsudin, Umar Hamzah, Zuraidah Ramli
    Sains Malaysiana, 2007;36:159-163.
    An integrated geophysical study was conducted to investigate the subsurface regional structure and the presence of a Quaternary sedimentary basin in the Olak Lempit - Banting area of Selangor, Malaysia. A regional gravity survey and the high resolution reflection seismic were employed to determine the thickness and areal distribution of the alluvial sedimentary basin as well as to investigate the depth and topography of the bedrock in the study area. The sedimentary basin hosts one of the most important coastal alluvial aquifer which was used to cater the shortage of domestic water supply during the worst water crisis that hit the state of Selangor in 1998. The surface geological map shows that in general 70% of the study area is covered by Quaternary deposits of Beruas, Gula and Simpang Formations which overlie the sedimentary bedrock of Kenny Hill Formation. The Beruas Formation consists of mainly clay, sandy clay and peat of Holocene fluviatile-estuarine deposits, whereas the Gula Formation represents Holocene marine to estuarine sediments which mostly consists of clay and minor sand. The Simpang Formation (Pleistocene) is a continental deposit comprising of gravel, sand, clay and silt. The underlying Kenny Hill Formation consists of a monotonous sequence of interbedded shales, mudstones and sandstones. The rock is Carbonaceous in age and it forms an undulating surface topography in the eastern part of the study area. A total of 121 gravity stations were established using a La Coste & Romberg gravity meter and the elevations of most of the stations were determined barometrically using Tiernan-Wallace altimeters. The high resolution seismic reflection using the common mid point (CMP) or roll along technique was carried out using a 24 channel signal enhancement seismograph and high frequency geophones. A total length of about 1.7 km stacked seismic section has been acquired in this survey and a nearby borehole data was used for interpretation. A relative Bouguer anomaly map shows an elongated zone of low gravity anomaly trending approximately NW-SE which is interpreted to be the deposition center of the Quaternary basin. The interpreted gravity profiles running across the central area of the study area show that the basin has thickness varies from tenth to several hundred meters with maximum depth to bedrock of about 275m. A gravity profile which passes through the eastern edge of the basin was modeled with depth to bedrock of about 178m below ground which agrees very well with those obtained from the interpreted seicmic section and borehole data. The stacked seismic section shows several high amplitude parallel to sub-parallel reflection overlying discontinuos and low reflection pattern. Reflections on the eastern part of the section is much shallower than the one observed on the western part which clearly indicates the presence of basinal structure with a total interpreted depth to bedrock of about 200 meters.
    MeSH terms: Aluminum Silicates; Geology; Malaysia; Surveys and Questionnaires; Running; Soil; Water; Water Supply; Hypogravity; Groundwater
  7. Wan Zuhairi W, Abdul Rahim S
    Sains Malaysiana, 2007;36:149-157.
    The sorption parameters of two heavy metals (i.e. Pb and Cu) in clay soils from Selangor were studied using batch equilibrium test. The test was conducted in two separate systems, i.e. single and mix solutions. The sorption isotherms data from this test were then used to calculate the sorption parameters, i.e. distribution coefficient (Kd) and maximum adsorption capacity (Am). Langmuir sorption equation was used to model the sorption data with the correlation coefficients (r2) higher than 0.6. The study has revealed that different soils have different sorption capacity for different heavy metals. The Kd values are proportional to the sorption capacity of the soils. The sorption of Pb and Cu in single solution is higher than in mix solution, due to the competition for sorption sites among heavy metals in mix solution. The Kd values for Pb in single solution ranging from 36.18-334.48 L/g and for Cu is 9.29-66.19 L/g. In mix solution, the Kd values for Pb and Cu are much smaller, ranging from 23.13-31.79 L/g and 3.95-18.53 L/g respectively. The Am values in single solution for both Pb and Cu are ranging from 0.48-1.09 mg/g dan 0.18-0.70 mg/g respectively. While in mix solution, the values of Am for Pb ranging from 0.20-1.11 mg/g and Cu within 0.18-0.60 mg/g.
    MeSH terms: Adsorption; Aluminum Silicates; Lead; Soil; Metals, Heavy
  8. Norela Sulaiman, Toh LF, Hazzila Abdul Samat, Ismail Sahid, Maimon Abdullah, Mohd. Rozali Othman
    Sains Malaysiana, 2007;36:91-95.
    This study was carried out to determine the concentrations of cypermethrin in total suspended particulate in air in several farming areas of Cameron Highlands. Samples of total suspended particulate were collected using a high volume air sampler (Model Graseby) from six different sampling sites around Cameron Highlands. Laboratory analysis of total suspended particulate was conducted by the standard method. High dosages of cypermethrin were used by farmers in the dry season. Results of the study showed that the concentrations of cypermethrin in total suspended particulate in the air samples were higher during the dry season (May-July 2004) compared to the rainy season (September-October 2004). There was a significant positive correlation between the concentrations of cypermethrin and total suspended particulate (p<0.05).
    MeSH terms: Farmers; Agriculture; Dust; Rain; Seasons; Farms
  9. Nurhaida Kamaruddin, Farah Diba Abu Bakar, Rohaiza Ahmad Redzuan, Nor Muhammad Mahadi, Abdul Munir Abdul Murad
    Sains Malaysiana, 2007;36:91-95.
    Effective and rapid methods for RNA extraction from conidia, germinating conidia and appressoria of the fungal plant pathogen, Colletotrichum gloeosporioides is reported in this study. The procedure for the RNA extraction from conidia and germinating conidia was carried out using TRI REAGENT® solution (Molecular Research Center, USA) and can be completed in less than one and a half hours. The procedure for RNA extraction from appressoria was carried out using a modified protocol employing guanidine isothiocyanate and mechanical cell disruption by glass beads. The efficiency of the RNA extraction procedures was evaluated by several measures to determine RNA integrity, purity and applicability in RT-PCR. RNA integrity was assessed by observing the integrity of the major RNA species (18S and 28S rRNA) on denaturing agarose gel electrophoresis. The ethidium bromide-staining pattern of intact total RNA extracted from the three fungal morphogenetic cells showed clearly defined 28S and 18S rRNA bands and no genomic DNA contamination. Spectrophotometric assessment of RNA from each sample indicated relatively high purity and absence of carbohydrate contamination. Finally, we have demonstrated that the methods used for RNA extraction of conidia, germinating conidia and appressoria produced RNA of sufficient quality suitable for RT-PCR in detecting the expression of protein kinase A regulatory subunit gene in C. gloeosporioides.
  10. Sapar S, Mohd Atan K
    Sains Malaysiana, 2007;36:77-82.
    Telah diketahui nilai hasil tambah eksponen S(f;pa) adalah bersandar kepada penganggaran bilangan unsur |V|, yang terdapat dalam set dengan menandakan polinomial-polinomial terbitan separa f terhadap . Kekardinalan bagi V pula bersandar kepada saiz p-adic pensifar sepunya terbitan separa .
    Makalah ini membentangkan suatu kaedah penentuan anggaran saiz p-adic bagi komponen (x,h) pensifar sepunya terbitan separa f(x,y) dalam berdarjah enam berasaskan teknik polihedron Newton yang disekutukan dengan polinomial terbabit. Polinomial berdarjah enam yang dipertimbangkan berbentuk. Anggaran yang diperolehi adalah dalam sebutan saiz p-adic pekali-pekali sebutan yang dominan dalam f.
    MeSH terms: Ion Transport
  11. Ahmad Nazlim Yusoff, Junaidah Mat Sani, Mustaffa Abdullah, Sahrim Ahmad, Nazree Ahmad
    Sains Malaysiana, 2007;36:65-67.
    The complex scattering parameters (S11* and S21*), relative dielectric permittivity (er* = er' - jer"), relative magnetic permeability (mr* = mr' - jmr") and absorption characteristics of some thermoplastic natural rubber (TPNR) – Fe3O4/YIG composites were investigated by means of a microwave vector network analyser and specular absorber method. The measurements were performed in the frequency range of 1 – 13 GHz with and without the presence of a transverse external magnetic field with magnitude of 1 T. The specular absorber method is used in determining the reflection loss (RL) of the composites and its dependence on material properties, thickness and the external magnetic field. In toroidal form, the composites under study seem to transmit more (Pt > 60%) but absorb and reflect less (Pa + Pr < 30%) microwave power in the frequency range used in this study and in both unmagnetised and magnetised states. The external magnetic field is seen to have the effects of reducing S11*, S21*, er', er", mr' and mr". The suppression of the relaxation and resonance behaviours on the mr' and mr" plots for all samples are observed for measurements performed in the presence of the external field. The composites, as revealed by the specular absorber method, show conditions of minimal reflection on RL versus frequency plot for all sample thickness where more than 95% of the microwave power is not reflected back. The location of the dips of minimal reflection on the frequency domain depend on the thickness, the dielectric and magnetic properties of the materials. The conditions of minimal reflection was found to occur when the thickness (t) of the sample equals the odd number multiple of a quarter wavelength in the material (lm), t = nlm/4 (n = 1, 3, 5, 7 …), where a geometrical cancellation took place at the surface of the absorber between the reflected waves, resembling a thin filem inteference phenomenon. The dips are suppressed and shifted to a higher frequency in the presence of the external magnetic field. With the knowledge of the dielectric permittivity and magnetic permeability of a material, the specular absorber method may provides a simple theoretical graphic aids in determining the absorption characteristics and location of the matching condition in the frequency domain.
  12. Samat S, Siaw S
    Sains Malaysiana, 2007;36:59-63.
    The 12 MeV electron beam reference depth zref at three field size FS 10 × 10 cm2, 15 × 15 cm2, 20 × 20 cm2 were determined for TRS277 and TRS398 IAEA protocols. At a fixed SSD = 100 cm, results showed that all zref TRS398 are higher than zref TRS277, in the range of 0.01 to 0.10 cm. Reasons for this is explained. For a particular zref of TRS398 at FS 10 × 10 cm2, comparison was made with earlier results obtained by other worker that used similar experimental set-up except a different linear accelerator. The present result is comparable since it is higher only by 0.11cm.
  13. Uda Hashim, Ramzan Mat Ayub, Nik Hazura N. Hamat
    Sains Malaysiana, 2007;36:53-57.
    This paper involves the planarization of borophosphosilicate glass (BPSG) film using a new recipe for annealing process to improve the borophosphosilicate glass (BPSG) film flatness after reflow. This improvement is for 0.35µm technology using steam annealing method at different temperatures. This process allows the planarization of wafers with thin layer at its surface. In this paper we present the comparison between the effect of hydrofluoric acid (HF) staining on the cross sectional topography with the samples without hydrofluoric acid (HF) staining analyzed by field emission scanning electron microscopy (FESEM). We found that staining with HF produced clearer images.
  14. Swesi AT, Yang Farina, Ibrahim Baba
    Sains Malaysiana, 2007;36:21-26.
    Organotin compounds especially the dialkyltin derivatives are reported to possess anti-tumour properties. The diorganotin(IV) complexes of the type Me2SnL1, Me2SnL2, Bu2SnL1, Bu2SnL2 and Ph2SnL1 (L1 and L2 is the anion of the thiosemicarbazone ligand formed by the condensation reaction of 2,3-dihydroxybenzaldehyde with thiosemicarbazide or its N(4)-methyl substituent) were synthesized using 1:1 metal-to-ligand reactant ratios. The newly synthesized complexes were characterized using elemental analysis, infrared and nuclear magnetic resonance (1H, 13C, 119Sn) spectroscopic techniques. Complex formation between the organotin(IV) moiety and the anions of 2,3-dihydroxybenzaldehyde thiosemicarbazone and 2,3-dihydroxybenzaldehyde 4-methylthiosemicarbazone occurred with chelation at the o-dihydroxy positions. The complexes are proposed to have tetrahedral geometry.
    MeSH terms: Anions; Magnetic Resonance Imaging; Metals; Neoplasms; Magnetic Resonance Spectroscopy; Organotin Compounds; Semicarbazides; Thiosemicarbazones
  15. Indah Raya, Ibrahim Baba, Bohari Mohd Yamin, Onggo D
    Sains Malaysiana, 2007;36:15-20.
    A new series of gadolinium complexes with mixed ligands, dialkyl dithiocarbamate and 1,10-Phenantroline were successfully synthesized using “in situ” methods. Microelemental analysis data of complexes are in agreement with the general formula Gd[S2CNR’R”]3Phen (R’ = ethyl, methyl; R” = butyl, heptyl, isopropyl, isobutyl, benzyl and cyclohexyl; Phen = 1,10-phenantroline). These complexes have been characterized using elemental analysis, infrared, thermogravimetric analysis, conductivity and magnetic measurements. Infrared spectra of complexes showed the thioureide n(C-N) bands were in the region of 1450 - 1490 cm-1. The single n(C-S) bands appeared in the region of 959 – 1003 cm-1 and n(C-H) bands in the region of 2853-2931 cm-1. The crystal structure of tris(N,N-methylbenzyldithiocarbamate)(1,10-phenantroline) gadolinium(III) adopts a triclinic system (space group Pī) with a distorted dodecahedron geometry with a = 11.04(6) Å , b = 12.65(7) Å, c = 17.13(10) Å, a =73.86o(8) b =74.54o(8) g = 72.34o(8) and Z = 2. Three dithiocarbamates and one phenanthroline ligands were coordinated to the central Gd atom in bidentate manner.
  16. Abu Hassan Shaari Mohd Nor, Tan YL, Fauziah Maarof
    Sains Malaysiana, 2007;36:225-232.
    The main objective of this paper is to explore the varying volatility dynamic of inflation rate in Malaysia for the period from January 1980 to December 2004. The GARCH, GARCH-Mean, EGARCH and EGARCH-Mean models are used to capture the stochastic variation and asymmetries in the economic instruments. Results show that the EGARCH model gives better estimates of sub-periods volatility. Further analysis using Granger causality test show that there is sufficient empirical evidence that higher inflation rate level will result in higher future inflation uncertainty and higher level of inflation uncertainty will lead to lower future inflation rate.
    MeSH terms: Forecasting; Inflation, Economic; Insufflation; Malaysia; Paper; Volatilization; Uncertainty
  17. Nurul Izzaty Hassan, Musa Ahmad
    Sains Malaysiana, 2007;36:189-194.
    Analisis kuantitatif untuk penentuan kepekatan ion Al3+ dalam larutan akueus telah dilakukan menggunakan reagen alizarin red S (ARS) melalui pembentukan kompleks ARS-Al(III) yang dianalisis menggunakan kaedah spektrofotometri UL-Nampak. Kompleks ARS-Al(III) memberikan puncak serapan pada panjang gelombang 484 nm pada pH 5. Kajian kestabilan foto bagi reagen ARS memberikan nilai RSD sebanyak 0.46 %. Analisis kebolehulangan memberikan nilai RSD sebanyak 1.07 % dan 0.67 % masing-masingnya bagi kepekatan Al(III) 0.2 ppm dan 9 ppm. Gangguan kation Cu2+ dan Fe3+ pada nisbah mol 1:10 adalah minimum. Kebanyakan anion penggangu tidak memberikan kesan gangguan kecuali F- pada nisbah mol 1:1 dan 1:10. Sistem ini memberikan julat kepekatan dinamik Al3+ antara 0.1 – 1.0 ppm. Arkitektur ANN dengan bilangan neuron terlindung, bilangan kitaran dan kadar pembelajaran adalah masing-masingnya 23, 40000 dan 0.001 telah berjaya memanjangkan julat dinamik kepekatan Al(III) daripada 0.1 – 8.0 ppm. Reagen ARS berjaya dipegunkan pada permukaan ko-polimer XAD 4 dan mampu memberikan respon optik yang baik terhadap ion Al3+.
  18. Rusli Daik, Yee LC
    Sains Malaysiana, 2007;36:183-188.
    Adunan polietilena berketumpatan rendah (LDPE)/getah asli cecair (LNR) dalam komposisi 100LDPE/0LNR, 70LDPE/30LNR, 60LDPE/40LNR dan 40LDPE/60LNR telah dihasilkan melalui penyebaran emulsi LDPE dan LNR.. LNR diperolehi melalui tindak balas pemekaan fotokimia ke atas getah asli (NR) dan emulsi LNR disediakan dengan menggunakan natrium dodesil sulfat (SDS) sebagai agen pengemulsi dan 1-heksanol sebagai ko-pengemulsi. Emulsi LDPE dihasilkan dengan cara yang sama menggunakan larutan LDPE dalam karbon tetraklorida, SDS dan 1-heksanol. Adunan LDPE/LNR disediakan melalui pencampuran emulsi LNR dan LDPE. Sifat mekanik adunan LDPE/LNR dianalisis melalui ujian regangan, hentaman dan kekerasan. Sifat mekanik optimum diperhatikan bagi adunan dengan komposisi 60LDPE/40LNR yang memberi nilai tegasan dan terikan yang maksimum. Suhu peralihan kaca, Tg, seperti yang diperolehi daripada analisis kalorimetri imbasan pembezaan (DSC) menunjukkan adunan yang dihasilkan adalah homogen. Kajian morfologi yang dilakukan dengan menggunakan mikroskop imbasan elektron (SEM) juga menunjukkan kehomogenan adunan yang dihasilkan.
    MeSH terms: Animals; Ataxia Telangiectasia; Lymphatic Metastasis; Polyethylene; Gastropoda
  19. Riyanto, Jumat Salimon, Mohamed Rozali Othman
    Sains Malaysiana, 2007;36:175-181.
    Elektrod platinum-polivinilklorida (Pt-PVC) untuk pengoksidaan elektrokimia etanol dalam larutan alkali telah direkabentuk. Elektrod Pt-PVC dibina dengan mencampurkan serbuk-serbuk logam platinum dengan PVC (95:5 w/w), diaduk untuk mendapatkan campuran yang homogen, ditambahkan dengan tetrahidrofuran (THF) untuk melarutkan PVC, dikeringkan, dimasukkan ke dalam acuan berdiameter 1 cm dan ditekan pada tekanan kira-kira 10 tan/cm2. Kajian elektrokimia dilakukan menggunakan voltammetri kitaran (CV) dan kronokoulometri (CC). CV untuk etanol yang menggunakan elektrod-elektrod kepingan logam Pt dan Pt-PVC masing-masing memberikan ketumpatan arus 0.25 mA/cm2 dan 85 mA/cm2 untuk puncak penjerapan hidroksida. Ini menunjukkan bahawa elektrod Pt-PVC mempunyai nilai konduktiviti dan perilaku elektrokimia yang lebih baik untuk pengoksidaan etanol dalam KOH berbanding elektrod kepingan logam Pt. Hasil kajian mendapati bahawa terdapat peningkatan peratus hasil elektrolisis dari 3.64% kepada 23.64% asid asetik apabila elektrod Pt-PVC digunakan untuk pengoksidaan elektrokimia 0.25 M etanol dalam larutan elektrolit 1.0 M KOH menggantikan elektrod kepingan logam Pt.
    MeSH terms: Ethanol; Alkalies; Platinum; Polyvinyl Chloride; Procarbazine; Receptor, Notch1
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