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.
Mechanical properties of blended polyethylene (PE) containing the antioxidant Irganox 1010 and the UV-absorber Tinuvin 326 were studied for future use as radiation capsule material for the TRIGA Mark II research reactor. High density and low density polyethylene were blended with the additives and tested for elongation at break, impact strength and gel content, before and after irradiation inside the nuclear reactor. Characterization via FTIR as well as determination of crystallization and melt transition temperatures through DSC were also conducted. It was found that the addition of the antioxidant at different amounts (from 0 to 4 phr) had various effects on the properties of the blended PE, with 0 phr being the amount at which there was the biggest increase in elongation at break and impact strength, post-irradiation.
Al/B4C composites with 0 wt.%, 5 wt.% and 10 wt.% of B4C were prepared by powder metallurgy and their properties were characterised successfully. Investigation of the effect of milling times (4, 8, 12, 16 hours) on microstructure, phase identification, hardness and neutron attenuation coefficient of composites has been studied. The results showed that hardness increased with increased of milling time, with maximum hardness obtained at 16 hours milling time. The increment is slower as the composition of B4C increased. The hardness of Al/10%B4C, Al/5%B4C and Al/0%B4C were 81.7, 78.7 and 61.2 HRB respectively. Morphology of scanning electron microscopy (SEM) showed that microstructures play important role in controlling the hardness. Meanwhile, x-ray diffraction (XRD) analysis showed the phases and crystalline present in composites with an indication that crystalline of the grain increased as the milling time increased. Neutron absorption of Al/10%B4C composites showed that this composite has the highest attenuation coefficient, thus indicating that it is the best composites for neutron shielding.
Assessing performance and genetic diversity of the wild material of oil palm is important for
under- standing genetic structure of natural oil palm populations towards improvement of the
crops. This in-formation is important for oil palm breeding programs, and also for continued exsitu
conservation of the germplasm and breeding program in Malaysia. Mutation induction is one
of the approaches in creating variants for selection in the breeding program. In this study, the
effect of irradiated pollen towards pollen viability, bunches formation and number of
parthenocarpic fruits were evaluated. Elaies guineensis Jacq. pollens were exposed to series of
acute gamma radiation at dose 0, 10, 20, 40, 50, 100, 200, 300, 500, 100 and 2000 Gy . Pollen
viability and pollen tube formation were disrupted in which unable the pollen to reach the ovule.
At this stage, embryo was aborted towards formation of parthenocarpic fruits and rotten bunches.
The study suggested that at low levels of irradiation i.e. < 200 Gy, generative nucleus partially
damage and it is still maintaining capacity of fertilizing the egg cells for hybridization. It is
important for breeders in understanding this finding towards novel variants of oil palm via
mutation induction
Many times a year natural gas transmission and distribution companies need to make new connections to pipelines to expand or modify their existing system through hot tapping procedure. This procedure involves the installation of a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure. The hot tap procedure includes attaching a branch connection and valve on the outside of an operating pipeline, and then cutting out the pipe-line wall within the branch and removing the wall section, which is called object of coupon through the valve. During the hot tapping process a critical problems occurred when a coupon fell into the mother pipeline. To overcome this problem, a gamma-ray absorption technique was chosen whereby a mapping technique will be done to detect the coupon position. The technique is non-destructive as it applies Co-60 (5mCi) as a radioisotope sealed source to emit gamma radiation and a NaI(Tl) scintillation as detector. The result provided a visible representation of density profile inside pipeline where the coupon location can be located. This paper provides the detail of the technique used and presents the result obtained.
Kenaf (Hibiscus cannabinus L.) is one of the world’s most economically important fiber crops particularly in Asia-Pacific region. Mutation induction is a method to increase genetic divergence associated with selection, recombination, or a combination of these approaches in plant breeding. One of preliminary procedures for an execellent mutation breeding program is the radiosensitivity study to determine the optimal doses for irradiation. A total of 10 different doses of acute gamma rays (0, 100, 200, 400, 800, 1000, 1200, 1500, 1700 and 2000 Gy) from ceasium-137 source were applied to the seeds of V 36 kenaf variety. The irradiated seeds including the control were planted in trough for 30 days. The gamma irradiation effects on several parameters such as seedling survival percentages, plant height, root length, shoot fresh weight, root frest weight, shoot dry weight and root dry weight were analysed. From the radiosensitivity curve, the LD50 and LD25 values were estimated at 810 and 310 Gy, respectively. Two doses (200 Gy and 300 Gy) based on LD25 were chosen for evaluating the effects of gamma irradiation on morphological traits in M1 generation. Irradiated and non-irradiated seeds were planted in the field at Beseri, Perlis. About 10 phenotypic traits of irradiated plants were observed and evaluated against the controls. Cluster analysis on M1 progenies showed that the mutation could be classified into eight genotypic groups. The first two components from principal component analysis explained about 77.99% of variation. Number of seeds per pod, weight of seeds per plant and dry stem biomass play an important role in explaining the variation since they showed positive correlated values for the first component analysis. Morphological changes such as flower shape, flower colour, and leaf shape were also observed in M1 generation. The findings of this study are important in determining the effectiveness of these doses in generating mutations on kenaf plant and subsequent breeding program to develop new kenaf varieties with enhanced quality traits.
Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image
formation and as well as scattered radiation. But there is paucity in the study related to heel effect.
This study is for mapping and profiling the dose on the surface of water phantom by using mobile
C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to at least
about 57% from anode to cathode bound of the irradiated area. This result and information can be
used as a guide to manipulate this phenomenon for better image quality and radiation safety for
this specific and dedicated fluoroscopy unit.
Detection and analysis of resin is particularly significant since the commercial value of agarwood is related to the quantity of resins that are present. This article explores the potential of a scanning electron microscope in combination with new non-destructive 3D visualization technique, X-ray micro-computed tomography, as imaging tools to visualize micro-structure resin in agarwood. These techniques were used to compare two samples of agarwood chips: high grade and low grade. From the results, it can be concluded that a wood cell filled with resin deposit have a higher attenuation. It can be shown that the combination of scanning electron microscopy and micro-CT can offer high resolution images concerning the localization and structure of resin inside Agarwood. While the second allows the 3D investigation of internal structure of agarwood, the first technique can provide details 2D morphological information. These imaging techniques, although sophisticated can be used for standard development especially in grading of agarwoodlbr commercial activities.
An improved laboratory technique for measurement of polonium-210(
210Po) in environmental
samples has been developed in Radiochemistry and Environmental Laboratory (RAS), Malaysian
Nuclear Agency. To further improve this technique, a study with the objectives to determine the
optimum conditions for
210Po deposition and; evaluate the accuracy and precision results for
the determination of 2 1 0 P o in environmental samples was carried-out. Polonium-210 which
is an alpha emitter obtained in acidic solution through total digestion and dissolution of samples
has been efficiently plated onto one side of the silver disc in the spontaneous plating process for
measurement of its alpha activity. The optimum conditions for deposition of 210Po were achieved
using hydrochloric acid (HCl) media at acidity of 0.5 M with the presence of 1.0 gram hydroxyl
ammonium chloride and the plating temperature at 90
oC. The plating was carried out in 80 mL
HCl solution (0.5 M) for 4 hours. The recorded recoveries obtained using 2 0 9 P o tracers in
the CRM IAEA-385 and environmental samples were 85% – 98% whereby the efficiency of the
new technique is a distinct advantage over the existing techniques. Therefore, optimization of
deposition parameters is a prime importance to achieve accuracy and precision results as well as
economy and time saving
“Batu Bersurat Terengganu (inscribed stone)” is the oldest artifact with Jawi writing on it. The
artifact proves that the Kingdom of Terengganu exist earlier than 1326 or 1386. To date, a lot of
studies on the content of the inscription have been carried out by historians and archaeologists, but
no scientific investigation about the material composition and its provenance has been performed.
This paper focuses on the study of the origin of the Batu Bersurat Terengganu using NeutronInduced
Prompt Gamma-Ray Techniques (NIPGAT). Portable NIPGAT system has been designed
and developed based on volumetric measurement methods and it will be considered as a nondestructive
testing. The system uses low activity of californium-252 (Cf-252) neutron radioactive
sources, gamma ray spectroscopy and special computer software to carry out the investigation. The
study found that the Batu Bersurat Terengganu is made of dolerite based on the elemental
composition of the stone. Although most of the scientific data for the study of the origin are already
obtained, but further research is still ongoing to complete the scope of this study.
The objective of this study was to measure indoor radon concentrations in the expected high risk area around Ipoh in Kinta Valley, Perak. The area was chosen based on its own special characteristics. The measurements were carried out by means of long term exposure (3 months) using CR-39 solid state nuclear track detector. The mean indoor radon concentration in Ipoh was 45 Bq/m3 which is equivalent to effective dose of 1.1 mSv/y. This value was higher compared to low or normal area in Bangi, Selangor but comparable to the world average value reported by UNSCEAR. The maximum value of indoor radon concentration measured was 87 Bq/m3.
Haruan or Channa striatus is source of protein that is widely consumed in the region and its extract
is well known for having medical values. It is of great advantage if this product could be taken
orally rather than by injection because the oral route of drug delivery is still preferred by the vast
majority of patients. However protein and peptides can be denatured or degraded by the acidic pH
of the stomach and the presence of endogenous enzymes. In order to protect or prevent digestion
and degradation of the protein in the stomach and to ensure the protein reaches the gastro
intestinal (GI) tract, Carboxymethyl Starch (CMS) nanogel system was developed using electron
irradiation method. However stability of HTE during the irradiation process needed to be studied
before being developed further. In this study, the HTE was irradiated using electron beams. Its
stability was analysed in terms of physical and chemical changes by looking at colour difference,
melting point by using Differential Scanning Calorimetry (DSC) and molecular bonds by using
Fourier Transform Infrared (FTIR) respectively. The results of this study were that no apparent
colour difference was observed with HTE before and after irradiation. These observations were
supported by the FTIR and DSC results that showed that there were no changes in molecular bonds
and melting point, compared between no irradiation and irradiation HTE during electron
irradiation up to 10 kGy. Statistically the test showed no significant difference at p < 0.005 between
melting temperatures.
The purpose of the study was to determine the effect of out-of-field photon beams radiotherapy to the cancer cell survival. In this study, HeLa and T24 cancer cells were irradiated with 6 MV and 10 MV photon beams in two different conditions, one with intercellular communication with the in-field cell and one without the communication. Cells survival was determined by clonogenic assay. In the presence of intercellular communication, the cell death was increased which indicate the presence of radiation induced bystander effects (RIBE). The effects were also dependent on the cell types and photon energy where the HeLa cells exhibit less survival compares to T24 cells and the effects were prominent at higher photon energy. This study demonstrates that the out-of-field cells in conjunction with RIBE plays important roles in the cells response towards megavoltage photon beam radiation therapy.
The objective of this study is to perform a thermoluminescent dosimetry (TLD) postal dose quality audit for megavoltage X-ray teletherapy units in Malaysia. This audit is essential to be carried out to ensure adequate precision in the dosimetry of clinical beams before being delivered to the patients. Through this work, participating centres were requested to irradiate three capsules of TLD-100 powder with an absorbed dose to water of 2 Gy for 6MV and10MV photon beams. The International Atomic Energy Agency (IAEA)’s Technical Report Series No. 398 is used as a reference standard for TLD irradiation. Atotal of 22photon beamsfrom ten radiotherapy centres comprising onegovernment hospital and nineprivate medical centres were evaluated. The percentage deviation of user’s measured absorbed dose relative to Secondary Standard Dosimetry Laboratory (SSDL) mean absorbed dose was calculated. The results showed that all photon beams are within the IAEA’s acceptance limit of ± 5% except six photon beams. These centres were followed up with a second round of TLD irradiation which resulted in a better compliance.As a conclusion, regular audits should be performed to ensure consistency of radiotherapy treatment unit performances thus maintaining the accuracy of dose delivered to patients inall radiotherapy centres in Malaysia.
Mushroom can be used as a biological indicator in assessing radiological impact on the
environment. Radiological effect would be reflected through morphological changes as well as
those changes at molecular level. For this purpose, a preliminary work was conducted, which
included DNA isolation, optimization of PCR parameters for Inter-Simple Sequence Repeat (ISSR)
and primers screening on Pleurotus sajor caju mushroom strains from Nuclear Malaysia’s
Sterifeed Mushrooms Collection Centre. In this work, DNA isolation technique from cap and stalk
of fruit body were optimized and quantified. It was found that stalk produced highest amount of
genomic DNA at 304.01ng/µl and cap at 149.00ng/µl. A total of 100 ISSR primers were tested and
51 primers were successfully amplified. These primers will be used further for dose response
evaluation and molecular profiling in mushroom species.
Qualitative and quantitative analysis of samples require good judgment from the analysts. These two aspects in gamma spectrometric analysis of Proficiency Test and solid radioactive waste samples for the determination of radionuclides are discussed. It is vital to judge and decide what energy peaks belong to which radionuclides prior to the creation of customized radionuclide library for the analysis of specific samples. Corrections due to radionuclide decay and growth, and the half-life assigned to a particular radionuclide in the uranium and thorium series are also discussed. Discussion on judgment to confirm the presence of thorium in food samples based on gamma spectrometry and neutron activation analysis is also provided.
Laboratory radiotracer experiment was performed to study the bioaccumulation of 109Cd and 134Cs in the Malaysian common fish White seabass (Lates calcarifer). The aim of this study was to compare the biokinetics of uptake these two contrasting radionuclides by White seabass in laboratory condition scale. Experiments were designed to determine the processes controlling uptake of both radionuclides following exposure via seawater. In this study, the curve shapes of the uptake kinetic of 109Cd and 134Cs in White seabass were slightly linear and gradually increased with increasing of exposure time but were not reach equilibrium in the period of the study of 21 days. This phenomenon can be concluded that radioelement concentrations of 109Cd and 134Cs; and exposure duration of this experiment may not adequately to reach steady-state condition for uptake kinetic of those radioelements in White seabass. Furthermore, this was indicated that the uptake rate of 109Cd was 1.79 times faster than 134Cs due to some factors may probably influenced the output of this experiment such as different element accumulation strategies, physiological, behavior of radioelements, etc.
In this paper, we report the dosimetry methodology used in the IAEA/WHO Thermoluminescent Dosimeter (TLD) Postal Dose Quality Audit Service and the results of 22 Malaysian radiotherapy centres participated in the audit from 2011 to 2015. Each participating centre was provided with a few sets of TLD capsule (two unit of TLD capsules to be irradiated and a control TLD in one set) as requested by the centres. The participating centres were asked to irradiate each TLD capsule at 2 Gy absorbed a dose to water under reference conditions i.e the TLD capsule is positioned at 10 cm depths in water, at central axis with 10 cm x 10 cm field size at 100 cm Source-Surface Distance or 100 cm Source-Axis Distance. In this period, a total of 70 photon beams consist of 43 beams and 27 beams produced by 6 MV and 10 MV photon beams, respectively have been audited. The results demonstrated that all participating centres comply with the acceptance limits of ± 5% as recommended by the International Commission on Radiation Units and Measurements (ICRU) Report 24, except eight photon beams from six centres. However, these centres presented better compliance results after being followed up with a second round of TLD irradiation.
The objective of this study was to examine the mammographic breast density of women with breast cancer detected on voluntary mammographic screening at two selected screening centersin Malaysia.This was a retrospective study of Full-Field Digital Mammography(FFDM) images of150 Malaysian women with biopsy-proven breast cancer. The study population comprised 73 Malays(37.7%), 59 Chinese (39.3%) and 18 Indians (12.0%). The Tabár breast density Patterns(I -V) wereused to evaluate mammographic breast density. Data were analyzed using descriptive statistics. The results were compared with findings from a similar study on a group of 668 women who did not have breast cancer.The results showed that 44.7% of the study populationhad dense breasts (Patterns IV and V), 14.7% had predominantly fatty breasts (Patterns II and III) while 40.7% had Pattern I. The proportion of study populationwith dense breasts decreased with age. In conclusion, the proportion of women with dense breasts decreased with age. Majority of the women with cancer (44.7%) had dense breasts of Tabár Patterns IV and V, which has been associated with increased risk of breast cancer detected by voluntary mammographic screening. The results support the notion that increased breast density is a risk factor of breast cancer.
The total mass attenuation coefficients (μ/ρ) of stainless steel (SS316L) and carbon steel (A516) that are widely used as petrochemical plant components, such as distillation column, heat exchanger, boiler and storage tank were measured at 662, 1073 and 1332 keV of photon energies. Measurements of radiation intensity for various thicknesses of steel were made by using transmission method. The γ-ray intensity were counted by using a Gamma spectrometer that contains a Hyper-pure Germanium (HPGe) detector connected with Multi Channel Analyzer (MCA). The effective numbers of atomic (Zeff) and electron (Neff) obtained experimentally were compared by those obtained through theoretical calculation. Both experimental and calculated values of Zeff and Neff were in good agreement.