Displaying publications 1 - 20 of 173 in total

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  1. Zakri, A.H.
    ASM Science Journal, 2009;3(2):200-202.
    MyJurnal
    Recent studies by the United Nations University - Institute of Advanced Studies (UNU-IAS) demonstrate that bioprospecting is taking place in Antarctica and the Southern Ocean and that related commercial applications were being marketed. The bioprospectors’ interest in Antarctica stems from two reasons. First, the lack of knowledge surrounding Antarctic biota provides opportunities to discover novel organisms of potential use to biotechnology. Second, Antarctica’s environmental extremes, such as cold temperatures, extreme aridity and salinity present conditions in which biota have evolved unique characteristics for survival (UNU-IAS 2003). Thus bioprospecting opportunities include, inter alia, the discovery of novel bioactives in species found in cold and dry lithic habitat, novel pigments found in hyper-saline lakes and antifreezes in sea-lakes (Cheng & Cheng 1999).
  2. Zakiyah, L.K., Gui, M.M., Foo, R.S., Mohamed, A.R., Chai, S.P.
    ASM Science Journal, 2011;5(2):91-100.
    MyJurnal
    The functionalization of pristine CNTs is necessary for carbon nanotubes (CNTs) to be fully utilized, with the aim of increasing the nanotube reactivity and solubility in aqueous solutions. In this study, multi-walled carbon nanotubes (MWCNTs) were functionalized with a carboxylic group as this was an important step prior to application. The carboxylic group-functionalization was conducted through acid treatment, using sulphuric and nitric acids mixed at a ratio of 3:1 (v/v) and sonication for 30 min under different temperatures and time durations. The functionalization conditions of 50ºC x 5 h and 60ºC x 3 h were identified to be most suitable for introducing a carboxylic group onto the nanotube surfaces. The percentage of total weight loss due to the carboxylic group on the MWCNTs treated at 50ºC x 5 h and 60ºC x 3 h obtained from the thermogravimetric analysis was 13.26% and 13.76%, respectively. For both samples, peaks corresponding to the carboxylic group were identified in the FT-IR spectra. The changes in the morphology of the treated MWCNTs were also observed under SEM analysis.
  3. Yusoff, M.H.M., Hassan, H.A., Hashim, M.R., Abd-Rahman, M.K.
    ASM Science Journal, 2008;2(2):139-148.
    MyJurnal
    The fabrication tolerance of a short and compact low refractive index grating waveguide polarisation splitter based on the principle of resonant tunnelling was analyzed in this study. The design utilised two grating waveguides with an intermediate conventional waveguide layer. The design and optimisation were conducted using the quasi 2-D effective index solver with global search algorithm. An optimum device operating at 1.55 μm wavelength was obtained at a length of 340 μm. The splitting ratios were calculated to be 36 dB and 15 dB, and the overall device transmission efficiencies, after considering the three-dimensional waveguide leakage loss, were estimated at 88% and 83% for tranverse magnetic and tranverse electric polarisation, respectively.
  4. Yusoff, A.N., Mohamad, M., Hamid, K.A., Hamid, A.I.A., Manan, H.A., Hashim, M.H.
    ASM Science Journal, 2010;4(2):158-172.
    MyJurnal
    In this multiple-subject study, intrinsic couplings between the primary motor (M1) and supplementary motor areas (SMA) were investigated. Unilateral (UNIright and UNIleft) self-paced tapping of hand fingers were performed to activate M1 and SMA. The intrinsic couplings were analysed using statistical parametric mapping, dynamic causal modeling (DCM) and Bayesian model analysis. Brain activation observed for UNIright and UNIleft showed contralateral and ipsilateral involvement of M1 and SMA. Ten full connectivity models were constructed with right and left M1 and SMA as processing centres. DCM indicated that all subjects prefer M1 as the intrinsic input for UNIright and UNIleft as indicated by a large group Bayes factor (GBF). Positive evidence ratio (PER) that showed strong evidence of Model 3 and Model 6 against other models in at least 12 out of 16 subjects, supported GBF results. The GBF and PER results were later found to be consistent with that of BMS for group studies with high expected posterior probability and exceedance probability. It was concluded that during unilateral finger tapping, the contralateral M1 would act as the input centre which in turn triggered the propagation of signals to SMA in the same hemisphere and to M1 and SMA in the opposite hemisphere.
  5. Yunus, N.A.M., Jaafar, H., Halin, I.A., Green, N.G.
    ASM Science Journal, 2014;8(1):29-35.
    MyJurnal
    This paper presents a suitable and unique system for observing dielectrophoretic particle separation in a microfluidic device. Details presented on the experimental setup used will enable real time examination, monitoring and analysis of carboxylate-modified latex sphere particles in a colloidal mixture. Observations of the particles were made possible through an optical setup that illuminates the particles that went through the microelectrode array in the microchannel that was controlled by two analog signal generators. Through the setup, it was easily observed that the latex sphere particles move at a flow rate of 0.2 μl/s without colliding or overlapping on each other and successfully separated in two bands left and right. The new separation of one finest particles size for finest purification with respect to frequency was also observed, obtained and analysed.
  6. Yahya, A., Sidek, O., Salleh, M.F.M.
    ASM Science Journal, 2010;4(1):48-54.
    MyJurnal
    Frequency hopping spread spectrum (FHSS) systems with partial band interference require appropriate compounding of spread spectrum modulation, error correcting code, diversity and decoding method to receive improved transmission signal. In this paper, a fast FHSS system with regular low-density parity-check codes was employed to cater some anti-jamming competence by using good waterfall and error floor performance. The performance evalution of the previously mentioned system was conducted in the presence of partial band noise jamming. The best possible design of the system was achieved with the combination of diversity level L=2 with a probability rate of at 0.7 dB which showed the robustness of the system.
  7. Wong, C.M.V.L., Chung, H.H., Aisyah, S., Omar, S., Cheah, Y.K., Maria de, L.G., et al.
    ASM Science Journal, 2009;3(2):107-112.
    MyJurnal
    There are relatively little data on bacteria with antimicrobial activities from Antarctic, especially from the South Shetland Islands when compared to the other parts of the world. Hence, this project was set to isolate and characterize bacteria that produce anti-microbial compounds from Greenwich Island (one of the South Shetland Islands), Antarctica. A total of 356 strains of bacteria were isolated from Greenwich Island. They were screened for antimicrobial activities against 13 Gram-negative and one Gram-positive indicator food-borne pathogens. Two out of the 356 Antarctic bacterial strains exhibited an antagonistic effect on the indicator strains, Escherichia coli, Salmonella spp., Klebsiella pneumoniae, Enterobacter cloacae, Vibrio parahaemolyticus and Bacillus cereus. The two Antarctic bacterial strains were designated as SS157 and SR13. Biochemical and 16S rDNA analysis indicated that the strain SS157 was closely related to Pseudomonas congelans while the strain SR13 was closely related to Pseudomonas tremae. The anti-microbial compounds produced by the two Antarctic bacteria were not sensitive to temperature and were not degraded by trypsin or pronase indicating that they were likely to be chemical compounds or antibiotics. Antimicrobial compounds from strains SS157 and SR13 were broad spectrum, and targeted both Gram-positive and negative pathogens.
  8. Wan M. Khairul, Foong, Y.D., Lee, O.J., Lim, S.K.J., Daud, A.I., Rahamathullah, R., et al.
    ASM Science Journal, 2018;11(101):124-135.
    MyJurnal
    A new class of liquid crystalline acetylide-imine system was successfully synthesized, characterized
    and deposited on indium tin oxide (ITO) coated substrate via electrochemical deposition
    method for potential organic film application. The relationship between liquid crystal
    molecular structure, phase transition temperature and electrical performance was evaluated.
    The mesomorphic properties were identified via polarized optic microscopy (POM) which displayed
    fan-shaped texture of smectic A phase and their corresponding transition enthalpies
    are in concurrence with DSC and TGA studies. The findings from the conductivity analysis
    revealed that the fabricated film exhibits good electrical performance where it displayed
    linear current-voltage relationship of I-V curve. Therefore, this proposed type of molecular
    framework has given an ideal indication to act as transporting material for application in
    optoelectronic devices.
  9. W. Wilonita, R. Nurliyana, D.D. Asma, M. Noorazizah, M.Y. Hirzun
    ASM Science Journal, 2013;7(2):105-112.
    MyJurnal
    Molecular markers have been intensively used in assisting breeding to reduce the time taken by conventional breeding as well as helping introgression of specific traits. Baseline analysis of known markers is crucial in developing a genetic database on disease and pest resistance for local rice germplasm which does not yet
    exist. In this study seven local rice varieties, including the popular MR219 and MRQ 74 and MRQ 76 (newly developed aromatic rice varieties), together with a foreign variety, Intani-2, were screened for genetic markers related to pest and disease resistance. One hundred and twenty-two type-related markers (SSR, STS, InDel and Allele-specific) for genes resistant to bacterial leaf blight, blast and brown planthopper were screened using PCR amplification and validated by sequencing. It was found that each variety had its own pattern of resistance. Using allele-specific markers namely pBPH9, pTA248 and Pisbdom were found to be the most efficient way to screen for the targeted genes. Of the seven varieties, MR219 and MR232 were found to have the highest distribution of markers for resistance genes against pest and diseases studied.
  10. Varatharajoo, R.
    ASM Science Journal, 2011;5(2):153-155.
    MyJurnal
    Malaysia has adopted various strategies in developing its space sector. Indigenous space technologies would enable a sustainable growth of the space field and at the same time develop the strategic space technologies. Therefore, issues related to the current space research level are fundamentally crucial to be highlighted. Subsequently, the space focus areas can be derived in order to meet the expectations of the national and international space technology growth requirements, which are moving on to a stronger posture in R&D. In the absence of a strong R&D national space industry leadership, the Malaysian space sector remains in a traditional downstream mode of the world space technology supply chain ever since. The space technology supply chain can be divided into the ground segment and the space segment. This paper examines the current space research activities in Malaysia within the framework of the space technology supply chain. As a result, a preliminary gap in the overview of space research in Malaysia is established.
  11. Teoh, P.H., Kuah, M.K., Lim, P.S., Muhammand, T.S.T., Najimudin, N., Chien, A.S.C.
    ASM Science Journal, 2010;4(2):123-132.
    MyJurnal
    The receptor-interacting protein 140 (RIP 140) is a well known nuclear repressor and has been shown to be crucial for female reproduction and metabolism. However, the function of this repressor in developmental processes is still unknown. We conducted a study to investigate the expression patterns of RIP 140 in developing zebrafish embryos. Semi-quantitative RT-PCR analysis revealed that RIP140 was highly expressed in the eye, swim bladder, reproductive and metabolic organs of adult zebrafish. During embryogenesis, RIP 140 mRNA was continuously expressed throughout all the developmental stages with the highest expression at 24 hours of post-fertilization (hpf). Furthermore, in situ hybridization whole-mounts revealed that the expression of this gene was mainly localized in the eyes, mid-brain, pectoral fin buds and somites. Therefore, this present study has provided a starting point for future investigations to examine the role of RIP 140 in the development of these organs.
  12. Teh, G.B., Wong, Y.C., Tilley, R.D.
    ASM Science Journal, 2014;8(1):21-28.
    MyJurnal
    Co(II)-Ti(IV)-substituted magnetoplumbite-type (M-type) barium ferrite nanoparticles were synthesized via the sol-gel technique employing ethylene glycol as the gel precursor. Structural and magnetic properties were characterised via X-ray diffraction (XRD), high resolution transmission electron microscopy and superconducting quantum interference device magnetometry. The particle sizes of the M-type BaCoXTiXFe12-2XO19 (0.2 ≤  ≤ 1.0) were found to be 900 Å – 1500 Å. The XRD results confirmed that the Co(II)-Ti(IV) substituted ferrites in the range of 0.2 ≤  ≤ 1.0 substitution had the M-type ferrite as the dominant phase. The hysteresis loss per-cycle decreased with increasing Co(II)-Ti(IV) substitution in M-type ferrites which showed reduced values in coercivity and remnant magnetisation with moderate effect on the saturation magnetisation.
  13. Tan, S.L.
    ASM Science Journal, 2015;9(1):21-27.
    MyJurnal
    Public awareness and understanding of the technology behind the creation of Genetically Modified Organisms
    (GMOs) varies greatly from country to country, and indeed within the different sectors of any one country. Perhaps,
    it is “the fear of the unknown” at work, or it is just a pure rejection of the idea that “Man is playing God”. For whatever
    reason, and for whatever vested interest, there is often widespread clamor for stringent studies to be carried out
    when conducting a risk assessment of GMOs.
    For example, in Indonesia, regulation on the release of GMOs requires studies on any impact on non-target
    organisms (NTOs) as well as on soil microorganisms (Machmud Thohari 2014). Similarly, in Vietnam, it is mandatory
    to determine if there is any impact to the soil environment or ecosystem (Truong 2014), while in Cambodia, there is
    worry over high levels of damage to NTOs and the environment from GMOs, because of the lack of capacity to cope
    with such damage if it occurs (Pisey 2014).
    All too often, opponents of modern biotechnology (a term used to define technologies resulting in GMOs), and,
    indeed, the regulators themselves forget that there is already a procedure in place to provide a check and balance;
    the risk assessment (RA) protocol. Most times, RA is far more stringent when conducted on GMOs compared with
    when exotic species which are non-GMOs are involved (Tan 2013). It is also overlooked that modern biotechnology
    can after all be considered a sophisticated new tool in plant breeding, an activity which has been practiced both by
    farmers and scientists for millennia, and a technology accepted by all and sundry.
    While GMOs are currently used in biological and medical research, for the production of pharmaceutical drugs,
    in experimental medicine (e.g. gene therapy) and in agriculture, this paper is confined to discussions on GMOs in
    agriculture.
  14. Tan, C.T., Chua, K.B., Wong, K.T.
    ASM Science Journal, 2009;3(1):91-96.
    MyJurnal
    The Nipah virus was first discovered in 1999, following a severe outbreak of viral encephalitis among pig farm workers in Malaysia. The virus was thought to have spread from Pteropus bats to pigs, then from infected pigs to humans by close contact. Mortality of the disease was high at about 40%. The main necropsy finding was disseminated microinfarction associated with vasculitis and direct neuronal involvement. Relapsed encephalitis was seen in approximately 10% of those who survived the initial illness. Since its first recorded emergence in peninsular Malaysia, 10 outbreaks of Nipah virus encephalitis have been reported in Bangladesh and West Bengal in India. The outbreaks occurred from January to May, with Pteropus giganteus as the reservoir of the virus. In Bangladesh, evidence indicated that the virus transmitted directly from bats to human, with human to human transmission as an important mode of spread. The mortality of the illness was higher in Bangladesh which stood at around 70%. This was likely to be due to genetic variation of the virus.
  15. Syafiqah, H.N., Umar, R., Kamarudin, M.K.A., Hazmin, S.N., Dianah, A.R.S.N., Jaafar, H., et al.
    ASM Science Journal, 2018;11(101):183-194.
    MyJurnal
    Nowadays, the wireless technology has become a lifestyle; even the children have their own
    mobile phones, although they are categorized as high risk susceptible to health problems
    due to radiation. Thus, the public exposure that stemmed from electromagnetic radiations
    become public concern since studies have been done and the finding showed that the repetitive
    and long term exposure may have adverse health effect. This study was conducted to
    evaluate the exposure level at UMT and UniSZA campuses by measuring the electric field
    strength. This measurement was conducted using omni-directional antenna below 4 GHz,
    connected to spectrum analyzer. In this paper, the measured values are compared with
    the previous study from several locations and then the spatial maps of exposure level are
    developed. The result shows that high exposure level was recorded at UMT and UniSZA.
    From this study, the findings may assist the Ministry of Health to monitor the public health
    due to non-ionizing radiation (NIR) exposure. This is crucial to make sure the international
    commission of non-ionizing radiation protection (ICNIRP) limit is complied. Moreover, the
    development of public NIR exposure policy can be initiated to the Malaysia government for
    health concern. For future study, the investigation of the suitable material used as antenna
    and casing or exposure reduction tool can be done to reduce NIR exposure rate on human
    body.
  16. Suratman, S., Tawnie, I., Sefei, A.
    ASM Science Journal, 2011;5(2):101-107.
    MyJurnal
    A study to determine the impact of leachate from operating and closed landfills into the surface water and groundwater systems in the state of Selangor was conducted in the year 2009. Groundwater was a major source of water for various uses in Selangor, Malaysia and was especially important for industrial purposes. The presence of high numbers of landfill sites was seen to have increased the risk of groundwater contamination. There were 20 landfill sites in the state of Selangor and seven of them were still operating and 13 closed. The landfills are classified into four categories, which were: (a) landfills operating at critical stages without controls to prevent pollution into the environment; (b) open dumpsites that have the capacity to continue to accept waste but needed to be upgraded to manage leachate and gas; (c) landfills that were closed but no safety closure plan was carried out; and (d) engineered landfills with up to date technologies. As most of the landfills were built prior to 1989, they were not subjected to the Environmental Impact Assessment requirements, hence, they were being poorly managed and were badly sited. The non-engineered sites had no proper pollution controls such as cover materials, liner materials, groundwater monitoring wells, leachate collection ponds and treatment, and methane gas collection pipes. This study revealed that the surface water and groundwater at and nearby the landfill sites were contaminated at various levels due to the landfill sites and operation. A comparison between the current quality of surface water and groundwater with their respective standards and background levels was carried out to survey the trend of the contamination. However, the limited financial resources hindered a very thorough investigation and restricted the number of samples collected and parameters analysed.
  17. Suparta, W., Samah, A.A., Harper, A.R.
    ASM Science Journal, 2009;3(2):152-160.
    MyJurnal
    Katabatic winds dramatically affect the polar climate. Their activity depends on density of air and temperature in the source region. This paper presents for first time an analysis of the precipitable water vapour (PWV) variability and its relation to a katabatic event at Scott Base station, Antarctica. A significant effect in their characteristics toward calculation of a reliable user accuracy in GPS applications is addressed. Our investigations using the data between 21st and 30th of November 2002 showed that the PWV profile exhibited an irregular pattern with a maximum value of 7.38 mm (~ 6 mm on average), and was more strongly influenced by relative humidity than by wind speed activity. The dominant wind flow during this period was from the North-Northeast (blowing from the Ross Sea) with a median speed of 4.96 ms–1. The PWV was high when the temperature was between –15ºC and –11ºC. During the dates identified as a katabatic event between 21:30 UT of 28th November and 18:40 UT on 29th November, the wind blew from the Southeast-South direction (from the Ross Ice Shelf) with a maximum speed of 10.92 ms–1. The PWV increased ~1.4 mm (23%) from the mean value, indicating severe wind during this event which had pronounced effect on GPS observations.
  18. Sugandi, G., Majlis, B.Y.
    ASM Science Journal, 2012;6(2):122-127.
    MyJurnal
    Since its invention, polyimide (PI) has been widely used in micro-electro-mechanical system (MEMS) devices. For fabrication, the PI membrane, PI-2723 HD-Microsystems was used as the membrane material due to its Young's modulus of 2.7 GPa and its film thickness could easily be controlled by changing the speed of the spin coater system. The application PI as membrane structure on silicon wafers therefore gave a much better mechanical performance then conventional membranes made of silicon dioxide (SiO2) or silicon nitride (Si3N4) layers. The fabrication of PI membrane was the same as for SiO2 and Si3N4 membranes; the basic step was to etch a side of the silicon wafer using wet anisotropic etching. This paper proposes an effective process for fabrication of PI membrane with f ast and little supervision. In this process, a dual step process was wet anisotropic etching of single crystal silicon using pottasium hydroxyl (KOH) with different concentrations and temperature processes. For the first process, 45% KOH under boiling temperature was used to etch at least 90%–95% of the silicon. In the second process, the silicon was submerged in 45% KOH with temperature at 70ºC–80ºC to etch away the residual silicon until a clean and transparent PI membrane was achieved. Using this method, the fabrication of PI membrane could be generated fast.
  19. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
  20. Siti-Balkhis, A.B., Yaman, I.C., Siti-Hasmah, I., Khalil, M.Z., Muhammad-Shukri, M.Y., Zulfigar, Y., et al.
    ASM Science Journal, 2014;8(2):159-164.
    MyJurnal
    A survey on the diversity of marine macrogastropoda
    in Pulau Songsong, Pulau Bidan and Pulau Telor on the
    Northern Straits of Malacca was conducted. Specimens
    were collected on rocky shores following NaGISA protocol
    and the number of marine macrogastropod were recorded.
    Distances and the number of the same species were
    converted into Relative Abundance unit (individuals per
    100 m2
    ). A total of 15 species of marine macrogastropoda
    were found from seven families namely Neritidae,
    Trochidae, Ceriitidae, Littorinidae, Turbinidae, Muricidae
    and Potamididae. Seven macrogastropoda species were
    newly recorded from these three islands. Morula marginatra
    was the most dominant species and Pulau Songsong had
    the highest genera and species diversity among the three
    islands. (Copied from article).
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