Displaying all 8 publications

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  1. Samat S, Too S, Kadni T, Dollah M
    The values of beam quality correction factor kQ that were experimentally determined from year 2002 to 2008 were analysed. As kQ is the function of ionization chamber and beam quality, the analysis were based on three cases namely (a) kQ(NE2571, 6 MV x-rays) that were determined from 17 measurements in the duration of 69 months at 6 radiotherapy centres, (b) kQ(NE2571, 10 MV x-rays) from 7 measurements in the duration of 12 months at one radiotherapy centre, and (c) kQ(NE2581, 6 MV x-rays) from 5 measurements in the duration of 5 months also at one radiotherapy centre. The purpose is to examine, in each case, the variation kQ for all the measurements. In other words, to see variation kQ with time. Results obtained are 0.993(NE2571, 6 MV), 0.986(NE2571, 10 MV) and 0.986(NE2581, 6 MV). This shows that in each case, despite the difference in the experimental data in getting kQ for all measurement, kQ remains constant with time. Reasons for this are explained.
    Matched MeSH terms: Relative Biological Effectiveness
  2. Maman Hermana, Hammad Hazim Mohd Azhar, Zuhar Zahir Tuan Harith
    Sains Malaysiana, 2012;41:953-959.
    This paper presents the improvement of quality factor (Q) estimation using shift frequency method. A new method was developed based on two previous methods; peak frequency shift (PFS) method and centroid frequency shift (CFS) method. The proposed algorithm has been tested to gauge its performance using three different scenarios; Q variation, travel
    time variation, and signal to noise ratio (SNR) variation. The test was performed using the Ricker wavelet with random noise included. Based on the results obtained, it can be concluded that the new proposed method was able to improve Q estimation using shift frequency method. This method can also be implemented in the low and high Q condition, shallow and deep wavelet targets and in the low and high SNR conditions of seismic data. The limitations in the PFS and CFS methods can be reduced by this method.
    Matched MeSH terms: Relative Biological Effectiveness
  3. Ali I, Jamaluddin MH, Gaya A, Rahim HA
    Sensors (Basel), 2020 Jan 26;20(3).
    PMID: 31991889 DOI: 10.3390/s20030675
    In this paper, a dielectric resonator antenna (DRA) with high gain and wide impedance bandwidth for fifth-generation (5G) wireless communication applications is proposed. The dielectric resonator antenna is designed to operate at higher-order TEδ15x mode to achieve high antenna gain, while a hollow cylinder at the center of the DRA is introduced to improve bandwidth by reducing the quality factor. The DRA is excited by a 50Ω microstrip line with a narrow aperture slot. The reflection coefficient, antenna gain, and radiation pattern of the proposed DRAs are analyzed using the commercially available full-wave electromagnetic simulation tool CST Microwave Studio (CST MWS). In order to verify the simulation results, the proposed antenna structures were fabricated and experimentally validated. Measured results of the fabricated prototypes show a 10-dB return loss impedance bandwidth of 10.7% (14.3-15.9GHz) and 16.1% (14.1-16.5 GHz) for DRA1 and DRA2, respectively, at the operating frequency of 15 GHz. The results show that the designed antenna structure can be used in the Internet of things (IoT) for device-to-device (D2D) communication in 5G systems.
    Matched MeSH terms: Relative Biological Effectiveness
  4. Shakinah Salleh, Zaiton Ahmad, Affrida Abu Hassan, Yahya Awang, Yutaka Oono
    MyJurnal
    Chrysanthemum morifolium is an important temperate cut flower for Malaysian floriculture
    industry and the lack of new local owned varieties led to this mutation breeding research. The
    objective of this study was to compare the effectiveness of ion beam irradiation in generating
    mutations on ray florets and nodal explants of Chrysanthemum morifolium cv. ‘Reagan Red’. Ion
    beams has become an efficient physical mutagen for mutation breeding. The ray florets and nodal
    explants were irradiated with ion beams at doses 0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy.
    The 50% of in vitro shoot regeneration (RD50) for ray florets explants was 2.0 Gy and for nodal
    explants was 4.0 Gy. Thus, relative biological effectiveness (RBE) for ray florets was found 2.0
    times higher than the nodal explants. The regenerated plantlets were planted in the greenhouse at
    MARDI, Cameron Highlands for morphological screening. Overall performance of survival
    plantlets derived from in vitro nodal and ray floret explants was recorded. The characters studied
    include plant morphology and flowering characteristic. The ray florets explants were found to be
    more sensitive to ion beam irradiation and generated more mutations as compared to nodal
    explants.
    Matched MeSH terms: Relative Biological Effectiveness
  5. Shakinah Salleh, Affrida Abu Hassan, Shuhaimi Shamsudin, Yahya Awang, Ab. Kahar Sandrang, Abdullah, Thohirah Lee
    MyJurnal
    Chrysanthemum morfolium is an important temperate cut flower and potted plant for Malaysian local market and exporter. Considering chrysanthemum as a popular vegetatively propagated ornamental plant, induce mutations for breeding purposes are more beneficial. Several of physical mutagens have been used in mutation breeding including x-rays, gamma rays and ion beams. Gamma rays and ion beams are from two different linear energy transfer (LET) which are low and high, respectively. The objective of this study was to compare the effectiveness of acute gamma and ion beam irradiation in generating flower colour mutations on nodal explants of Chrysanthemum morifblium cv. Reagan Red'. The nodal explants were irradiated with acute gamma (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 Gy) and ion beam (0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy). The optimal dose for in vitro shoot regeneration using acute gamma was in the range of 10 to .15.0Gy and for ion beam was between 3.5 to 4.OGv. Relative biological effectiveness for ion beam was found 3.75 higher than the acute gamma. The regenerated plantlets were planted in the greenhouse at MARDI, Cameron Highland for morphological screening. The highest frequency of flower colour mutation for acute gamma was 77.8% whilst for ion beam were between 42.3 to 58.3%.
    Matched MeSH terms: Relative Biological Effectiveness
  6. Yousif AA, Bin Bahari I, Yasir MS
    Curr Radiopharm, 2012 Jan;5(1):34-7.
    PMID: 21864247
    Inactivation constant for V79 cells has been extracted from radiobiology experiments that utilize charged particles to irradiate mammal cells in vitro. Physical parameters such as effective charge, radiation mean free path and linear ionization which characterized protons and heluim-4 particles are determined using of standard values. The relationship between inactivation constant α and physical quality parameters have been determined, in this research, for protons and heluim-4 particles. This approach allows getting the characteristic biological response of inactivation of V79 cells in terms of each selected physical quality parameter. The best regression models are formulated for each obtained relationship.
    Matched MeSH terms: Relative Biological Effectiveness
  7. Noriah MA
    Radiat Prot Dosimetry, 2007;125(1-4):101-4.
    PMID: 17145724
    This paper discusses the advantage of certification process in the quality assurance of individual dose monitoring in Malaysia. The demand by customers and the regulatory authority for a higher degree of quality service requires a switch in emphasis from a technically focused quality assurance program to a comprehensive quality management for service provision. Achieving the ISO 9001:2000 certification by an accredited third party demonstrates acceptable recognition and documents the fact that the methods used are capable of generating results that satisfy the performance criteria of the certification program. It also offers a proof of the commitment to quality and, as a benchmark, allows measurement of the progress for continual improvement of service performance.
    Matched MeSH terms: Relative Biological Effectiveness
  8. Hambali AS, Ng KH, Abdullah BJ, Wang HB, Jamal N, Spelic DC, et al.
    Radiat Prot Dosimetry, 2009 Jan;133(1):25-34.
    PMID: 19223292 DOI: 10.1093/rpd/ncp007
    This study was undertaken to compare the entrance surface dose (ESD) and image quality of adult chest and abdominal X-ray examinations conducted at general practitioner (GP) clinics, and public and private hospitals in Malaysia. The surveyed facilities were randomly selected within a given category (28 GP clinics, 20 public hospitals and 15 private hospitals). Only departmental X-ray units were involved in the survey. Chest examinations were done at all facilities, while only hospitals performed abdominal examinations. This study used the x-ray attenuation phantoms and protocols developed for the Nationwide Evaluation of X-ray Trends (NEXT) survey program in the United States. The ESD was calculated from measurements of exposure and clinical geometry. An image quality test tool was used to evaluate the low-contrast detectability and high-contrast detail performance under typical clinical conditions. The median ESD value for the adult chest X-ray examination was the highest (0.25 mGy) at GP clinics, followed by private hospitals (0.22 mGy) and public hospitals (0.17 mGy). The median ESD for the adult abdominal X-ray examination at public hospitals (3.35 mGy) was higher than that for private hospitals (2.81 mGy). Results of image quality assessment for the chest X-ray examination show that all facility types have a similar median spatial resolution and low-contrast detectability. For the abdominal X-ray examination, public hospitals have a similar median spatial resolution but larger low-contrast detectability compared with private hospitals. The results of this survey clearly show that there is room for further improvement in performing chest and abdominal X-ray examinations in Malaysia.
    Matched MeSH terms: Relative Biological Effectiveness
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