A study has been carried out using a gamma-ray spectrometric system to determine the natural
radioactivity level in bricks made from industrial waste and their associated radiation hazard.
Brick-1 and brick-2 contained waste from coal power plant and granite industry, respectively. The
leachability of radionuclides from these bricks was also investigated. The activity concentration
values of 226Ra,
228Ra,
232Th, and 40K are 64.25, 63.15, 67.9 and 254.19 Bq/kg, respectively in brick-
1, and 193, 164.48, 164.63 and 1348.75 Bq/kg, respectively in brick-2. The radiation hazard
indexes such as radium equivalent activities (Raeq), representative level index (Iγr), external hazard
index (Hex) and internal hazard index (Hin) were calculated and compared with the internationally
approved values. Results indicate that brick-1 showed less radiological hazard than brick-2. This
suggested that brick-1 could be used in building construction without exceeding the proposed
criterion level.The leachability of 226Ra for bricks showed the activity concentration slightly
exceeded 1 Bq/L which is the limit generally used for industrial wastewater.
MeSH terms: Coal; Industrial Waste; Power Plants; Radioactivity; Radioisotopes; Radium; Silicon Dioxide; Spectrometry, Gamma; Waste Water
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
Present of 241Am in the environment is being determined as part of surveillance and research
programs related to nuclear activities. The separation of 241Am from environmental samples was
carried out against the IAEA’s reference material by using an improved in-house radiochemical
separation method through anion exchange column, followed by the electro-deposition on a
stainless steel disc, and finally assayed on alpha spectrometry counting system. The resulting
spectra showed good isolated peak, indicating a good separation of the radionuclide of interest.
The analytical results were in good agreement with the certified value for IAEA-326 and IAEA-368
with the calculated U-score was 0.36 and 0.82, respectively, showing no significant difference
between the experimental and certified value. Using this method, distributions of 241Am in seabed
surface sediment in the Exclusive Economic Zone of East Coast Peninsular Malaysia were studied.
Samples were collected during June 2008 where the concentrations of 241Am were found to be
ranged from < 0.08 to 0.36 Bq/kg, dry weight.
The acrylated palm oil (APO) nanoparticle is a potential product that can be used as carriers in
medical field. The main focus of the present study was to study the potential of the APO
nanoparticles for used in a controlled drug delivery system. The microemulsion system is used as a
medium to incorporate an active substance such as Thymoquinone (TQ) into the APO polymeric
micelle and then the radiation technique is used as a tool for the synthesis of TQ-loaded APO
nanoparticle. The nano-size TQ-loaded APO particles resulted the particle size of less than 150 nm
with spherical in shape. The TQ release profile was carried out in potassium buffer saline (PBS)
solutions (pH 7.4) at 37
oC. And, the zero-order model has been used to determine the mechanism
of the drug release from the corresponding nanoparticles, respectively. The TQ release was found
to be sustained and controlled in pH 7.4. At pH 7.4, the release of TQ followed the zero-order
model. The in-vitro drug release study showed a good prospect of the APO nanoparticle on being a
potential drug carrier as there are toxic against colon cancer cells and not toxic towards normal
cells. This suggested that the APO product produce using this radiation technique can be
developed into different type of carrier systems for controlled drug release applications.
MeSH terms: Colonic Neoplasms; Delayed-Action Preparations; Drug Carriers; Micelles; Particle Size; Plant Oils; Polymers; Potassium; Benzoquinones; Drug Delivery Systems; Nanoparticles; Drug Liberation
“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 1 MW TRIGA MARK II research reactor at Malaysian Nuclear Agency achieved initial
criticality on June 28, 1982. The reactor is designed to effectively implement the various fields of
basic nuclear research, manpower training, and production of radioisotopes. This
paperdescribes the reactor parameters calculation for the PUSPATI TRIGA REACTOR (RTP);
focusing on the application of the developed reactor 3D model for criticality calculation,
analysis of power and neutron flux distribution and depletion study of TRIGA fuel. The 3D
continuous energy Monte Carlo code MCNP was used to develop a versatile and accurate full
model of the TRIGA reactor. The consistency and accuracy of the developed RTP MCNP model
was established by comparing calculations to the experimental results and TRIGLAV
code.MCNP and TRIGLAV criticality prediction of the critical core loading are in a very good
agreement with the experimental results.Power peaking factor calculated with TRIGLAV are
systematically higher than the MCNP but the trends are the same.Depletion calculation by both
codes show differences especially at high burnup.The results are conservative and can be
applied to show the reliability of MCNP code and the model both for design and verification of
the reactor core, and future calculation of its neutronic parameters.
MeSH terms: Monte Carlo Method; Neutrons; Radioisotopes; Research; Reproducibility of Results
The glow curve in TLD-100 was compared by applying long preheat time, short preheat time
techniques and without preheat technique before the TLD readout. Fading effect of the TLD signal
upon certain storage time with long preheat time (100°C, 10 minutes using the oven) and short
preheat time techniques (100°C, 10 seconds using the reader) were also studied. 15 TLD-100 chips
were used with 3 of the TLD chips were used for measuring background radiation. 12 TLD chips
were annealed, irradiated, preheated long and short preheat time techniques) and analyzed. The TL
signals output from TLD chips of without preheated were used as the control. Two sets of data were
taken using TLD chips irradiated with 6 MV and 10 MV photon beams. TL signal output was
recorded the highest for short preheat time, followed by long preheat time and no preheating. The
TL signal loss upon certain storage time was also reduced when short preheat time technique was
applied. By applying long preheat time technique the low temperature peak in the glow curve was
completely removed for both energies. Whereas, TLD chips exposed to 6 MV and with short preheat
time technique the low temperature peak did not disappear completely but decreased in intensity as
compared to the control data by 19.80%, 37.69%, 48.19% and 100% at 24, 48, 72 and 96 hours
after exposure prior to readout, respectively. Meanwhile, for 10 MV photon beam with short
preheat time, the small peak intensity was reduced by 19.58% for readout at 24 hours after
irradiation and 100% for 48,72 and 96 hours delayed time prior to readout. It was observed that
the TLD-100 was highly dependent on preheat heating time before readout. Short preheat time
technique was able to reduce post irradiation fading of TLD-100 dosimeters
This paper aims at presenting preliminary results of a survey on physical factors, namely tube
potential (kV), tube current exposure time product (mAs) and compressed breast thickness (CBT)
during voluntary mammography screening using Full-Field Digital Mammography (FFDM) System
in Malaysia. Retrospective data were collected from 1128 FFDM images of 282 women from three
major ethnic groups (Malay, Chinese and Indian) who underwent voluntary screening
mammography at Breast Centre, International Islamic University Malaysia from January to March
2008. Results from the present study were then compared with results from the previous study on
Screen-Film Mammography System (SFM) according to the ethnic group for both Cranio-caudal
(CC) and Mediol-Lateral (MLO) views. We found that the mean kV for CC view for the three ethnic
groups are Malay (28), Chinese (28) and Indian (28), and for MLO view are Malay (29), Chinese
(28) and Indian (29). These values are higher than the kV for SFM which were Malay (26), Chinese
(27) and Indian (26) for CC and Malay (26), Chinese (27) and Indian (26) for CC and MLO views
respectively. The mean mAs for CC and MLO views for FFDM were lower compared to SFM
systems. These values were Malay (104), Chinese (108) and Indian (91) for CC views and Malay
(106), Chinese (105), and Indian (94) for MLO views for the FFDM system. The values for SFM
system are for CC and MLO views were Malay (120), Chinese (106) and Indian (126), and Malay
(166), Chinese (132), Indian (183) respectively. The median CBT for CC and MLO views increased
by 27% and 7% respectively on the FFDM compared to the SFM system. In conclusion, the FFDM
operates with higher kV, lower mAs, and higher CBT when compared with SFM system. Median
CBT on CC and MLO view with FFDM system are 27% and 7% higher respectively compared to
the SFM. We are currently collecting data on mean glandular dose with FFDM systems to assess
how the change in local mammography practice influences this value. This will allow comparison
with related data from other parts of the world.
MeSH terms: Breast; Ethnic Groups; Female; Humans; Malaysia; Mammography; Surveys and Questionnaires; Retrospective Studies; Universities; Early Detection of Cancer
Development of biofertilizer seed treatments for okra seeds were carried out by mixing phosphate
solubilising bacteria (AP 3) and plant growth promoter (AP 2) with adhesives. The seeds were
coated with inoculums and four types of adhesives namely, Gum Arabic; Polyethylene Glycol
(PEG); Sodium Alginate and Methycellulose respectively. From eight seed treatments, all seed
treatments significantly increased seed germinations except treatment T4 (Gum Arabic and AP3).
In general, maximum germination rates and log of viable cells were observed when treated with
polyethylene glycol 4000 (PEG) mixed with AP2 (T7) and AP3 (T8). These results show that using
PEG as adhesive enhanced the germination rates and log of viable cells of AP2 and AP3. Thus,
PEG could be a good adhesive for seed treatment. In greenhouse experiment, okra seeds treatment
with AP2 and PEG (T1) showed the highest dry weight compared to other treatments. Seeds
treatment with AP3 and PEG (T2) showed higher contribution of N compare to seeds treatment
(T1). There were no significant different within seed treatments and urea treatment in okra yield.
All treatments significantly increased yields compared with control
Effects of 3 MeV electron (10 mA) irradiation at room temperature on the phase, microstructure,
electrical and life time properties of 4H-SiC wafer were investigated by scanning electron
microscopy (SEM), X-ray diffraction (XRD), four point probe current-voltage measurements and
positron annihilation spectroscopy. It was found that irradiation damage in SiC wafer is
significantly increased with the increase of radiation dose as observed in SEM. Irradiation also
resulted in modification of crystallite size as identified by XRD. The resistance of a sample before
irradiation was found to be 0.8 MΩ, whereas for a sample irradiated at 200 kGy, the resistance as
measured by four point probe was 5.2 MΩ. It seems that the increase of resistance hence, reduction
in conductivities could be due to defects induced by the radiation dose received then created
leakage currents at both reverse and low-forward biases and creation of traps in the SiC.
Meanwhile positron annihilation spectroscopy (PAS) was used to analyse the life time of irradiated
samples which nonetheless shows that all irradiated sample have similar life time of 151 ps. It was
observed that that no degradation process of materials experienced by SiC wafer irradiated at 500
kGy.
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.
Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.
Tocochromanols (tocopherols and tocotrienols) unitedly known as vitamin E, are the necessary antioxidant components of both human and animal diets. There is a considerable interest in plants with increased or customized vitamin E content, due to their potential health benefits. To quantify the tocochromanol content and determine the expression of a key tocotrienol biosynthesis gene among a set of contrasting red pericarp and light brown rice genotypes of advanced breeding lines together with their parents; expression pattern of homogentisate geranylgeranyl transferase (HGGT), the key gene was studied by semi-quantitative RT-PCR in milky and matured grain stages. Vitamin E analysis was carried out by high performance liquid chromatography (HPLC). The chloroform-methanolic extracts prepared from red pericarp and light brown rice advanced breeding lines showed significant differences for vitamin E content. Averaged across all samples, the content of γ-tocotrienol > α-tocopherol > α-tocotrienol > γ-tocopherol > δ-tocotrienol, and total E vitamin content ranged from 10.30 to 31.65 µg/g. Genotype G37 (red pericarp) was found to have higher expression than G7 (light brown) and G33 (red pericarp) at both grain development stages but lower than both parents whereas their transcript levels were comparatively lower in mature grain, which indicates their possible regulation by plant growth stage. HPLC results of γ-tocotrienol content supported gene expression results with the exception of the recurrent parent MR219.
An awareness of Escherichia coli as a foodborne pathogen and illness causing bacterium has been increased among consumers. Moreover, there is demand for natural product in order to reduce synthetic product that can cause toxic to the human. In this study, antibacterial activity, in term of MIC, MBC and killing-time curve of methanolic extract of Boesenbergia rotunda have been tested against a standard E. coli ATCC 25922 and two E. coli isolated from milk products using Clinical and Laboratory Standard Institute (CLSI) methods. The results show that B. rotunda extract was susceptible to all E. coli strains. The MIC and MBC values of B. rotunda extract against E. coli ranged 0.019 mg/mL 2.5 mg/mL and 0.039 mg/mL – 5.0 µg/mL, respectively. Killing-time curves were constructed at concentrations of 0x MIC, 1/2x MIC, 1x MIC, and 2x MIC. All E. coli strains can be killed with concentration of 2x MIC after 2 hours. The results show that B. rotunda extract has potential antibacterial activity against E. coli.
Foodborne diseases are mainly caused by bacterial contamination which can lead to severe diarrhea. This study aimed to detect the presence of Shiga toxin-Producing Escherichia coli O157, Escherichia coli non-O157 and virulence gene in raw vegetables. The samples were purchased from wet market and hypermarket in Selangor. The detections were carried out by using the combination methods of Most Probable Number-Polymerase Chain Reaction (MPNPCR). A total of 37(18.5%) samples were found to be contaminated by STEC. Out of these 37 isolates, four (10.8%) of the isolates were E. coli O157 while 33(89.2%) were E. coli nonO157. However, there was no E. coli O157:H7 detected in all the samples. The occurrence of Shiga toxin-Producing E. coli in edible raw vegetables samples suggests the importance of this pathogen in vegetables. Therefore, more studies are required to remove this pathogen from vegetables.
Shiga toxin-producing E. coli (STEC) is an important foodborne pathogen causing diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome in humans. STEC is an implicated in the vast majority of outbreaks, widely via consumption of STEC contaminated beef, as important vehicle of transmission of this organism to human. The E. coli O157:H7 serotype is traditionally identified by serological identification of the somatic antigen (O157) and structural flagella (H7). In this study, the bacteria were identified as STEC serotype O157:H7 with three primer pairs that amplified fragments of secD, rfbE and fliC genes in PCR assays. These primer pairs specifically amplified different sizes of target genes: a 244bp region of the E. coli diagnostic marker gene (secD); a 317bp region of the O157 lipopolysacharide (LPS) gene (rfbE); and a 381bp region of the H7 flagellin gene (fliC). The singleplex, duplex and triplex PCR assay developed in this study have a sensitivity limit at 2.8 x 103, 2.8 x 105 and 2.8 x 107 CFU/ml of E. coli O157:H7, respectively. Sensitivity to detect trace amount of E. coli O157:H7 DNA was reduced as the number of primer used was increased for competing to the same DNA template.
Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and trh gene, increasing prevalence demands an effective fingerprinting scheme which can constantly monitor and trace the sources of such emerging food pathogens. By using ERIC-, RAPD-, and BOX-PCR methods, 33 Vibrio parahaemolyticus isolates from local Malaysia bloody clam (Anadara granosa) and Lala (Orbicularia orbiculata) with confirmed presence of tdh and trh gene were characterised, followed by determination of clonal relatedness among virulent strains using cluster analysis and discriminatory index. This study also involved application of Immunomagnetic Separation (IMS) Method which significantly improved the specificity of strain isolation. Cluster analysis using Unweighted Pair Group Mathematical Averaging (UPGMA) and Dice Coefficient shown clustering according to isolation food source, IMS level and haemolysin gene possessed. Nevertheless, different DNA fingerprinting methods generated different clustering at different similarity cut-off percentage, regardless as individual or as composite dendrograms. ERIC- and RAPD-PCR composite fingerprinting relatively shown the highest discriminatory index at following similarity cutoff percentage: 0.68 at 50%; 0.83 at 65%; and 0.93 at 75%. Discriminatory power increased with similarity cut-off percentage. However, result also suggested that BOX-PCR might be an effective fingerprinting tool, as it generated three clusters with no single-colony isolate at 70% similarity cut-off. This study not only achieved its objective to determine clonal relatedness among virulent strains from local seafood via characterisation, but also speculated the best possible combination of molecular typing methods to effectively do so.
MeSH terms: Hemolysin Proteins; Malaysia; Vibrio parahaemolyticus; Prevalence; Cluster Analysis; Polymerase Chain Reaction; DNA Fingerprinting; Seafood; Immunomagnetic Separation; Random Amplified Polymorphic DNA Technique; Bivalvia; Arcidae; Molecular Typing
This study was done to determine the effects of different thermal drying methods (sun drying, microwave drying and hot air oven drying) on the total phenolic content (TPC), total anthocyanin content and the antioxidant properties of Vitex negundo (VN) tea. Significant decline (P < 0.05) in antioxidant properties of hot air oven drying shows that this method is not the best method to preserve antioxidant compounds in VN tea. As a conclusion, microwave drying has been found to be a good method for maintain the TPC, anthocyanin content and AEAC in dried sample of VN tea.
Henna plant (Lawsonia inermis) is an Indian medicinal plant used in traditional medicine for the treatment of various diseases, besides its popularity as a natural dye to colour hand and hair. Research in the recent past has accumulated enormous evidence revealing henna plant to be an excellent source of antioxidants such as total phenolics. In this study, the extraction of total phenolics from henna stems was evaluated using the Folin-Ciocalteu assay. A set of single factor experiments was carried out for identifying the optimum condition of each independent variable affecting total phenolic content (TPC) extraction efficiency of henna stems, namely the solvent type, solvent concentration (v/v, %), extraction time (min) and extraction temperature (oC). Generally, high extraction yield was obtained using aqueous acetone (about 40%) as solvent and the extraction yield could further be increased using a prolonged time of 270 min and a higher incubation temperature of 55°C. Under these optimized conditions, the experimental maximum yield of TPC of 5554.15 ± 73.04 mg GAE/100 g DW was obtained.