This study was conducted to evaluatethe nitrogen use efficiency and 13C isotope discrimination of rice mutant lines viz.NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a shade house. The rice mutant lines were planted on sandy loam soil. Three watering regimes and three nitrogen levels in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under three water potentials, (i) Field capacity from 0 to 40 DAS and saturated from 41 to 110 DAS [ST], (ii) Field capacity from 0 to 110 DAS [FC], and (iii) Field capacity from 0 to 40 DAS and 70% of field capacity from 41 to 110 DAS [SS]. Direct 15N isotopic tracer method was used in this study, whereby the 15N labelled urea fertilizer 5.20% atom excess (a.e) was utilized as a tracer for nitroge nuse efficiency study (NUE)by the test crops. 15Nisotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. 15N a.e values of the samples were used in the determination of the efficiency of N used by the mutant varieties. The 13C isotope discrimination (Δ13C) technique was used as a tool to identify drought resistance rice species with improves water use efficiency (WUE). WUE is the ratio of the biomass produced by the water consumed. For 13C discrimination analysis, a sample of rice leaf was analyzed for 13C content by using Isotope Ratio Mass Spectrometer (IRMS).The parameter, viz. plant height, number of tillers, grain yield, 1000 grain weight, NUE, Δ13Cand WUE were recorded. Results from this study showed nitrogen rates imparted significant effects on plant height, number of tillers, grain yield, 1000 grain weight and WUE, while water potentials had significant effects on plant height, grain yield, 1000 grain weight, NUE, Δ13Cand WUE. Δ13C has a low but significantly negative relationship with WUE. Rice mutants NMR151 and NMR152 were found to be not significantly different except for their NUE.
A study to determine whether Radiological Impact Assessment (RIA) is needed for landfill disposal of treated sludge (slag) from oil and gas industries has been carried out. Radioactivity level of slag and soil samples have been measured using gamma spectrometry system and its Total Activity Concentration (TAC) has been calculated. It was found that TAC (inclusive background) was within the control limit set by the AELB i.e. 3 Bq/g as stipulated in LEM/TEK 58 (AELB, 2009). Therefore, as a result from this study, RIA is not required and the allocated area can be used for the landfill disposal of treated sludge (slag).
Mixed organic liquid waste generated from health-care and research activities containing tritium, carbon-14, and other radionuclide posed specific challenges in its management. Often, this waste becomes legacy waste in many nuclear facilities and being considered as ‘problematic’ waste. One of the most important recommendations made by IAEA is to perform multistage processes aiming at declassification of the waste. At this moment, approximately 3000 bottles of mixed liquid waste, with estimated volume of 6000 litres are currently stored at the National Radioactive Waste Management Centre, Malaysia and some have been stored for more than 25 years. The aim of this study is to develop a characterization protocol towards reclassification of these wastes. The characterization protocol entails waste identification, waste screening and segregation, and analytical radionuclides profiling using analytical procedures involving gross alpha beta, and gamma spectrometry. The results obtained from the characterization protocol are used to establish criteria for speedy classification of the waste.
A safety evaluation test on human for latex films made from Radiation Prevulcanized Natural Rubber Latex (RVNRL) with sulfur-containing antioxidant was studied. Sulfur test has confirmed that there was sulfur compound presence in RVNRL derived from antioxidant used in this study. Two types of safety evaluation test were being adopted which are Patch Test and Modified Draize-95 test and this test proved that there is no clinical evidence on the presence of sulfur compound in RVNRL that may induce Type IV allergy in the unsensitized general user population. Both clinical test shows that the highest score value produced by test subjects is 1 and not exceed the allowable limit.
Medical radioisotope is a small quantity of radioactive substance used for the purpose of diagnostic and therapy of various diseases. In Malaysia, the emerging of new nuclear medicine centers or institutions in both government and private sectors rose abruptly for the past few years. Currently, there are no data available on the usage and demand of these medical radioisotope or radiopharmaceuticals. The aim of this study is to assess current medical radioisotopes and radiopharmaceuticals usage and also to provide data on current medical radioisotope and radiopharmaceuticals demand for both private and government hospitals or institutions in Malaysia. A survey for a period of 3 months was conducted across Malaysia. The survey was divided into five (5) main parts and it was distributed among healthcare professionalsinvolved working with medical radioisotope and radiopharmaceuticals in private, government and university based hospitals or institutions and was distributed manually either by hand, mail ore-mail.Data is presented in either pie chart or bar chart. Survey results found out that the highest demand and the highest usage among all radioisotopes are Technetium-99m and radioiodine isotopes such as the iodine-131, iodine-131 MIBG, iodine-123 and iodine-123 MIBG. Technetium-99m is the backbone of nuclear medicine whereby more than 80% of Nuclear Medicine services utilize this radioisotope. Technetium-99m supply chain is unstable globally and in coming future, two main reactors that produce 60% of world Molybdenum-99 will shut down and the supply of molybdenum-99 will be disrupted. In radioiodine services, currently, Iodine-123 can’t be obtained in Malaysia and neighboring countries due to its short half-life. Iodine-123 is useful in diagnostic of thyroid related diseases. As for PET services, the highest demands are F-18 FDG and gallium-68 Generator. It is important for Malaysia to self-produced medical radioisotope and radiopharmaceuticals to meet the local market demand.
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.
Gamma irradiation is widely used in sterilizationand mutagenesis,especially for plant breeding and crop protection. Microbial mutagenesisthrough gamma irradiation is mainly applied in fermentation industry. In agriculture, gamma irradiation is mostlyapplied in cropimprovement. Microbial mutagenesis is mainly applied against fungus and spore-forming bacteria,which are resistant to gamma irradiation.Response of microbes to gamma irradiation varies and depends on various factors. Reviewof previous works on gamma irradiation for microbial mutagenesis in agriculture may provide some information for the use of this method. Thegeneral view ongamma irradiation, its application,and mutagenesis are discussedin this paper. Further investigation onmicrobial mutagenesis should consider molecular changes,information on which is lacking in previous works.Moreover, studies on microbial mutagenesis are still lacking in Malaysiadespite having severalgamma irradiation facilities.Therefore, further studies on microbial mutagenesis should be conducted.
Radiotracer technology is a technique of radioactive injection into the systemand the detection is done using radiationdetector.It is alsoa tool for investigating and solving plant process problems namely process malfunctions andmechanical damages. Radiotracer is the most preferred stimulus response techniques in the industries due to its non-invasive application and on line monitoring capabilities, which avoid shut down of the plant. Radiotracer techniques have many advantages, such as high detection sensitivity, in-situ detection, availability of a wide range of compatible radiotracers for different phases, rapid response and high reliability and accuracy of the results. The residence time distribution (RTD) is one of the important parameters that can provide information on the characteristics or hydrodynamics of the nuclear reactor. In this paper, the overall review is presented in brief regarding radiotracer technology in plant operation.
Stable isotope analysis has widely been used to trace the origin of organic materials in various fields, such as geochemistry, biochemistry, archeology and petroleum. In past a decade, it has also become an important tool for food traceability study. The globalisation of food markets and the relative ease which food commodities are transported through and between countries and continentsmeans that consumers are increasingly concerned about the origin of the foods they eat. The natural abundance of stable isotope variation such as carbon, nitrogen, hydrogen and oxygen are usedas geographic tracersor marker to determine the geographic origin of fruits, crop, vegetables and food products from animal. The isotopic compositions of plant materials reflect various factors such as isotopic compositions of source materials and their assimilation processes as well as growth environments. This paper will discuss on stable carbon and nitrogen isotopic compositions inricethat been determined by Isotope Ratio Mass Spectromety, advantages, limitations and potential of other analysis applicationsthat can be incorporated in food traceability system.
Results ofthe bioaccumulation study anddose assessmentof Th-232 in whole-body Anabas testudineus are presented. The objective of this study was to evaluate the effect of Th-232 concentration activity on the laboratory bioaccumulation and total dose rate in Anabas testudineus. Anabas testudineus adults were exposed to different waterborne Th-232 levels: 0 Bq/L (control), 50 Bq/L and 100 Bq/L for 30 day (uptake phase). Whole-body uptakesof Th-232 in Anabas testudineuswere calculated and total dose ratesusing ERICA Assessment Tool were also estimated. The results showed the increase of waterborne Th-232 concentration corresponded to a progressive increase of Th-232accumulation and total dose rate (internal and external) in whole-body Anabas testudineus.Considering the ERICA dose rate screening value of 10 μGy/h, the findings can be concluded the estimated of total dose rate (0.38 –1.29μGy/h) in Anabas testudineuswasin orderof small magnitude. Nevertheless, these results showed that the Anabas testudineushas a potential to accumulate thorium.
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.
A 3.375 kJ plasma focus is designed to operate at 13.5 kV for studying X-ray source in Argon discharge. X-rays are detected by a film from the mammography radiographic plate using radiography technique. The feasibility of plasma focus as a high intensity flash X-ray radiation for a good contrast in radiography image is presented.
This study was performed to observe the variation in the distribution of 210Po,210Pb and 210Po/210Pb activity ratio throughtheir vertical profile of the sediment cores takenat surrounding Sungai Linggi estuary. Five sediment cores were takenin February 2011 and were cutto an intervalof 2 cm layer. Activity concentrations of 210Po and 210Pb were determined using alpha radiochemical analysis and gamma direct measurement, respectively. Generally, the measured activity of 210Po, 210Pb and 210Po/210Pbwere in the ranges of 22.73 –139.06 Bqkg-1dw., 37.88 –176.24 Bqkg-1dw.and 0.23 –1.34, respectively. The variation in the distribution profile for the radionuclides are believed to be influencedby human activities such as agriculture, fertilizer, vehicles, burned fuel fossil and forest, industrialand others via river input from land-base.Other factor is due to organic mattercontent played importantrole as the geochemical carrier to transportthose radionuclides at study area. It was provedthat hasa strong correlation between the radionuclide distribution and the sedimentcomposition of organic matter.Furthermore, in those rangesreflectedthat 210Pb activities were higher than210Po with an activity ratio average of 0.79. This is probably due to dramatic increase of excess 210Pb supplied from atmospheric deposition, in situ decay of 226Ra and as a result of diagenetic remolibilazationof 210Pbin deeper layesof the sediment column. Thus, thosefactors are majorcontributions on thevariation of 210Po and 210Pb in the sediment core at surrounding Sungai Linggi estuary.
Natural radioactivityin thesurface soil from thevicinity of Lynas Rare-earth plantin Kuantan, Pahanghad been studied with aim of evaluating environmental radioacitivityof thatarea. The radioactivities of the samples have been measured usinga low-background HPGe gamma detector. The concentration of 226Ra ranged found to be between 8.7 –76.9 Bq/kg (mean 33.7 Bq/kg); activity of 238U from 8.7 to 80.5 Bq/kg (mean 36.9 Bq/kg); as for 232Th, it ranged from 6.2 to 121.5 Bq/kg(mean 58.2 Bq/kg)and that of 40K,the values was from 19.1 to 778.9 Bq/kg (mean of 221.3 Bq/kg). Activity standard deviation for226Ra, 238U, 232Th and 40K were 14.2 Bq/kg, 14.7 Bq/kg, 26.1 Bq/kg and 185.6 Bq/kg, respectively. To evaluate the risk of radiation hazard to human, several parameters, i.e. the radium equivalent activity, External hazard index, Representative level index and dose rate in air from the terrestrial natural gamma radiation were calculatedwith the mean valuesfound to be136.7 Bq/kg, 0.4, 1.0, 65 nGy/h, respectively. The data were discussed and compared with those obtained from the previous studies given in the literatures. Thisstudy found that themean dose equivalent received by an individual at the vicinity area (outdoor) of Lynas plant was estimated to be 82.0 Sv/yr, whichis far below the annual dose limitof1,000 Sv/yrfor general public as stipulated in the national act.
Sludge and scales produced during oil and gas production contain enhanced naturally occurring
radioactive material (NORM). Sludge and scales are under the jurisdiction of Department of
Environment (DOE) and also Atomic Energy Licensing Board (AELB). AELB has issued a
guideline regarding the disposal of sludge and scales as in its guideline (LEM/TEK/30 SEM.2,
1996). In this guideline, Radiological Impact Assessment (RIA) should be carried out on all
proposed disposals and has to demonstrate that no member of public will be exposed to more than
1 mSv/y. This paper presented RIA analysis using RESRAD computer code for the disposal of
treated sludge. RESRAD (RESidual RADioactive) developed by Argonne National Laboratory is to
estimate radiation doses and risks from residual radioactive materials. The dose received by the
member of public is found to be well below the stipulated limit.
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.
Non-destructive and real time method becomes a well-liked method to researchers in the oil palm
industry since 2000. This method has the ability to detect oil content in order to increase the
production of oil palm for better profit. Hence, this research investigates the potential of neutron
source to estimate oil content in palm oil fruit since oil palm contains hydrogen with chemical
formula C55H96O6. For this paper, oil palm loose fruit was being used and divided into three
groups. These three groups are ripe, under-ripe and bruised fruit. A total of 21 loose fruit for each
group were collected from a private plantation in Malaysia. Each sample was scanned using
neutron backscattered technique. The higher neutron count, the more hydrogen content, and the
more oil content in palm oil fruit. The best correlation result came from the ripe fruits with r2=0.98.
This research proves that neutron backscattered technique can be used as a non-destructive and
real time grading system for palm oil.
On March 11, 2011, a serious accident occurred in Daiichi nuclear reactor plant, Fukushima,
Japan which caused radioactive materials been released into the atmosphere in the form of
aerosols and dust particles. Sea water around the plant was also found contaminated with high
radioactivity readings. These radioactive materials could be transported by the winds and ocean
current across international borders and cannot be controlled by human. Thus, a continuous
monitoring activity of radionuclide content in the air and sea water needs to be conducted by the
authorities. In addition to radioactivity monitoring, Malaysia should also control the entry of
contaminated food in order to prevent radionuclide ingestion by human. The radionuclide 131I,
134Cs and 137Cs were used as a measure of pollution levels and counted with gamma spectrometry
using standard analysis method suggested by AOAC International. In this paper, details description
of the role of Radiochemical and Environment Group, Nuclear Malaysia who’s responsible in
analyzing the radioactivity in the food samples due to Fukushima Daiichi, Japan accident was
included. The radioactivity limit adopted and analysis results from this monitoring were discussed
The assessment of surface dose is essential in radiotherapy to avoid deterministic effect or to
reduce the severity of side effects from radiation treatment. In this study, the surface dose for breast
cancer radiotherapy was measured using two types of dosimeter; Thermoluminescent Dosimeter
(TLD) and Optically Stimulated Luminescent Dosimeter (OSLD). The study was performed on the
left breast of female Alderson Radiation Therapy (ART) phantom. The treatment planning was
carried out on the ART phantom to determine the homogeneity of dose distribution within the target
organ is complied with the tolerance limits of 95% to 107% as recommended by the International
Commission on Radiation Units and Measurements (ICRU)’s Report No. 50. From the treatment
planning result, the phantom then was irradiated with 267 cGy dose per fraction for two beam
fields; medial tangential and lateral tangential fields using a 6 MV photon beam produced from
three-dimensional (3D) conformal radiotherapy. Result shows that the OSLD provides 25.7% and
23.5% higher surface dose compared to TLD for medial tangential and lateral tangential fields,
respectively. This condition may be due to higher effective point of measurement and angular
dependence of the OSLD compared to TLD. As a conclusion, suitable dosimeter should be selected
to ensure accurate estimation of surface dose could be made thus reduction of skin reaction to
patient could be achieved.
This paper studies about water obtained from fish pond of fisheries research centre. Usual water
quality parameters such as pH, COD, Turbidity and Ammonia content were analyzed before and
after irradiation. Electron beam irradiation was used to irradiate the water with the dose 100 kGy,
200 kGy and 300 kGy. Only high dose was applied on this water as only a limited amount of
samples was supplied. All the parameters indicated a slight increase after irradiation except for the
ammonia content, which showed a gradual decrease as irradiation dose increases. Sample
condition was changed before irradiation in order to obtain more effective results in the following
batch. The water sample from fisheries was diluted with distilled water to the ratio of 1:1.This was
followed with irradiation at 100 kGy, 200 kGy and 300 kGy. The results still showed an increase in
all parameters after irradiation except for ammonia content. For the following irradiation batch,
the pH of the sample was adjusted to pH 4 and pH 8 before irradiation. For this sample the
irradiation dose selected was only 100 kGy. A higher value of ammonia was observed for the
sample with pH 4 after irradiation. Other parameters were almost the same as the first two batches