Radiotherapy causes various complications including low immunity. Past research has shown that the low immunity is due to the low amount of lymphocytes and consumption of citrullus vulgaris will alleviate this problem. Based on this a study was conducted to identify how citrullus vulgaris was able to produce radioprotection on the lymphocyte membrane. A total of 30 adult male Sprague-Dawley rats were used and divided into three equals groups of positive control, negative control and treatment. For seven days, positive control and negative control were force fed with normal saline of 40 ml/kg animal weight while the treatment group received 40 g/kg animal weight fresh juice of citrullus vulgaris daily. After a week positive control and treatment group were irradiated with 0.9 Gy gamma ray. Viable lymphocyte were determined using propidium iodine and acridine orange stain. Results clearly shows that positive control, negative and treatment group were significantly different at 34 3% , 80 2% and 71 2% respectively. SEM results shows that pores were present on the membrane of the positive control while the negative control had none. Similar results were also found on the treatment group. Based on the result it had shown that citrullus vulgaris had radioprotection properties and lymphocytes were destroyed by the formation of pores on their membrane. It is very likely that the radioprotection properties could be due to the presence of antioxidants particularly vitamin A, C and lycopene. In conclusion, citrullus vulgaris could be used as a safe radioprotection agent.
The objective of this study is to compare low-contrast detectability of computed radiography (CR) and screen/film (SF) mammography systems. The Nijimegen contrast detail test object (CDMAM type 3.4) was imaged at 28 kV, in automatic exposure control mode separately. Six medical imaging physicists read each CDMAM phantom image. Contrast detail curves were plotted to compare lowcontrast detectability of CR (soft copy and hard copy) and SF mammography systems. Effect of varying exposure parameters, namely kV, object position inside the breast phantom, and entrance surface exposure (ESE) on the contrast detail curve were also investigated using soft copy CR. The significance of the difference in contrast between CR and SF, and for each exposure parameter, was tested using non-parametric Kruskal-Wallis test. The low- contrast detectability of the CR (soft copy and hard copy) system was found to be not significantly different to that of the SF system (p>0.05, Kruskal-Wallis test). For CR soft copy, no significant relationship (p>0.05, Kruskal-Wallis test) was seen for variation of kV, object position inside the breast phantom and ESE. This indicates that CR is comparable with SF for useful detection and visualization of low-contrast objects such as small lowcontrast areas corresponding to breast pathology.
The blooming use of ionizing radiation in industry, research, agriculture, medicine and nuclear industry increases the risk of overexposure for radiation workers as well as members of the public. Ionizing radiation is a strong clastogen, causing chromosome breakage, and resulting in cytogenetic aberrations in exposed cells. Cytogenetic analysis of human blood lymphocytes has been widely used as the biological technique for quantifying radiation dose in man. In the investigation of radiation accident, it is important to estimate the dose absorbed by the exposed person in order for the attending medical doctor to plan for their therapy. This paper reviews the current status on cytogenetic biodosimetry methods for radiation dose assessment.
Electrical capacitance tomography (ECT) velocimetry technique was utilized in this study to quantify the flow structure of gas-liquid based on the ECT images. A new 8 electrodes sensor ECT has been successfully developed to provide 2D images in a cross section of pipeline. The ECT has been attentively applied in the test section of the flow rig for imaging the gas-liquid distribution. The inside diameter of ECT pipeline sensor is 100mm. Meanwhile, the flow rig consists of close loop of “CPVC” pipes that includes a pipe test section, two tanks of oil and water respectively and allows the working pressure up to 5 bars. Transparent pipe is used for visual monitoring. A portable Doppler flow meter that utilizes the ultrasonic signal has also been placed at the test section to measure the velocity. The images obtained by ECT show that the different flow patterns have been observed in the horizontal pipe during the experiment. The technique enables realization of the time and position at which particle density fluctuations with respect to dominant time-space levels pass through the pipeline.
A laboratory scale test rig to treat simulated flue gas using electron beam technology was installed at the Alurtron EB-Irradiation Center, MINT. The experiment test rig was proposed as a result of feasibility studies conducted jointly by IAEA, MINT and TNB Research in 1997. The test rig system consists of several components, among others, diesel generator sets, pipe ducts, spray cooler, ammonia dosage system, irradiation vessel, bag filter and gas analyzers. The installation was completed and commissioned in October 2001. Results from the commissioning test runs and subsequent experimental work showed that the efficiency of flue gas treatment is high. It was proven that electron beam technology might be applied in the treatment of air pollutants. This paper describes the design and work function of the individual major components as well as the full system function. Results from the initial experimental works are also presented.
Various palm oil (RBD Palm Olein) based urethane acrylate prepolymers (UPs) having different structures and molecular weights were synthesised from palm oil based polyols, diisocyanate compounds and hydroxyl terminated acrylate monomers by following established synthesis procedures described elsewhere. The products (UPs) were compared with each other in terms of their molecular weights (MW), viscosities and UV curing performances of pressure sensitive adhesives (PSA) UP based formulations. The molecular structure of diisocyanate compounds and hydroxyl acrylate monomers tend to determine the molecular weights and hence viscosities of the final products of urethane acrylate prepolymers (UP), whereas, the MW of the UP has no direct effects on the coatings and adhesive properties of UV curable UP based PSA.
The main component of most building materials in Malaysia is rocks. These rocks have been found to naturally contain U-238, Th-232 and K-40. In order to estimate the radiological impact to the dweller, the level of radionuclides present in various building materials available in Malaysia were analyzed using gamma spectrometry. The radiation hazard indexes were calculated based on the above results. The results showed that the activity concentration of natural radionuclides U-238, Th-232, K-40 were between 19.0 Bq/kg – 42.2 Bq/kg, 16.5 Bq/kg –28.8 Bq/kg and 243.3 Bq/kg – 614.2 Bq/kg respectively. On the whole the radionuclides concentrations were still below the global average of 50 Bq/kg, 50 Bq/kg and 500 Bq/kg for U-238, Th-232 and K-40 respectively. The radiation hazard indexes of the building materials were also lower than the maximum value suggested.
The studies of ¹³⁷Cs content in the seawater surrounding Peninsular Malaysia had been carried out as part of the Malaysia Marine Radioactivity Database Project. The results of the measurement will serve as the baseline data and reference level to Malaysia. A numbers of sampling locations, including coastal and offshore at the East Coast (South China Sea) and West Coast (Straits of Malacca) of Peninsular Malaysia had been selected for the study. From each location at the coastal area, water samples were collected from the surface of the seawater. Meanwhile, for the offshore area, water samples have been collected at three different depths. Due to usual low concentration of ¹³⁷Cs in the marine environment, large volumes of seawater were collected and the co precipitation technique was employed to concentrate the ¹³⁷Cs. The activity of ¹³⁷Cs was determined by measuring the peak area under photo peak of the gamma spectrum at 661 keV, which is equivalent to the gamma intensity corrected to the HpGe detection efficiency and percentage of gamma ray abundance of the ¹³⁴Cs. At each study location, there were no significant differences for ¹³⁷Cs activities at 95% confidence interval. The activities of ¹³⁷Cs found to be quite uniformly distributed in the range of 2.33 to 5.00 Bq/m3and 1.76 to 4.76 Bq/m3for the South China Sea and the Straits of Malacca, respectively.
An instrumental neutron activation analytical (INAA) technique is used for the determination of thirty elements in five coal samples collected from Kapar power station, imported from Indonesia and Australia. Analyses of the samples are being associated with standards. All irradiations were performed in the nuclear reactor of Malaysia Nuclear Agency (MNA). Samples were counted by Hyper Pure Germanium (HPGe) detector for short period irradiations at MNA, while for the long period irradiations the samples were counted at Universiti Kebangsaan Malaysia (UKM). The concentrations of thirty elements have been determined: The major components are Cl, Ca, Mg, K, Fe, Ti and Na with the mean concentrations in the range between 70±69 ppm- 6100±1639 ppm; and the trace elements are Zr, V, Mn , Sc, Cr, Co, As ,Br ,Rb ,Sb ,Ba , La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Th, U and Ta with the mean concentrations in the range between 0.1381±0.0202 - 69.0±2.8 ppm. The results have been compared to the reported data of eight coal samples from the United States and the reported data of Australian bituminous coal.
Al-Si/SiC composites with the fraction of 5 and 15 wt. % fine SiC particles were fabricated using stir casting process by which SiC powders were poured into aluminium melt and cast in a stainless steel mould to form ingot. Characterization by X-ray diffraction (XRD) analysis showed the presence of constituent and intermetallic materials in the composites. Microstructure study revealed that both fine and course particles scattered in the Al-Si matrix. The characterization of thermal properties showed that the thermal conductivity and coefficient of thermal expansion decreased with the increase in SiC content. The conductivity and expansion behavior is correlated to the microstructure and weight fraction of the SiC particles. Meanwhile, the hardness of the composite increased with the increasing of SiC particles in the composites.
The objective of this study was to compare the acquired image of teflon, human bone equivalent material on a Positron Emission Tomography/Computed Tomography (PET/CT) scanner with Monte Carlo simulation (MCNP). The cylindrical shape teflon phantom with dimensions of 19.5 cm length and 5.0 cm diameter was used for imaging with different settings of kilovolts (kV) and milliamperes (mA) of PET/CT. In this simulation, the photon flux in each pixel was accumulated by the Flux Image Radiograph (FIR) tally as flux image detectors and the image was plotted using Microsoft Office Excel. Results show that MCNP image was comparable with that of CT image and the obtained MCNP image depends on pixels size of the FIR tally.
The interference of 235 U on 226 Ra concentration measured directly using the γ-ray energy of 186 keV and the interference of 228 Ac on the 40 K analysis by gamma-spectrometry system were highlighted and discussed. The interference of 235 U was demonstrated to be very significant, i.e. 45% of the 226 Ra concentration measured directly at 186 keV in natural samples containing uranium series in equilibrium. The interference of 228 Ac on 40 K concentration was particularly significant for samples containing high concentration of 228 Ac ( 228 Ra) such as radioactive minerals. Another important aspect discussed is the assignment of the right emission probability of the 583 keV and 2614 keV of the 208 Tl for the purpose of estimating the concentration of 232 Th or other radionuclides in the thorium series. Extra cautions are required in the interpretation of the measured 208 Tl concentration in samples of various natures. It is suggested that the emission probability used for 208 Tl be reported for comparison and verification.
XRF analysis was done on a local zircon samples and the result shows it has a high Fe, Th and U content. The high Fe content in Malaysian zircon had made the mineral to be classified as of a low-grade zircon. Presence of Fe in this mineral may be resulted from clay mineral coating found on the zircon surface. Chemical leaching technique was used for the removal of this Fe and the study also shows that a 600 o C heat pretreatment stage is important for the effectiveness of this process. Other parameters studied are the HCl concentration, leaching temperature and time. By using the optimum leaching parameters, the Fe content had been reduced to 0.049% and thus qualified it to be categorised as a premium grade zircon.
β-tricalcium phosphate (β-TCP) powders were synthesized by using various particles sizes (40 nm – 780 μm) calcium carbonate (CaCO3) and phosphoric acid (H3PO4) at room temperature (25 ˚C). The synthesized powders were characterized by using X-Ray Diffraction (XRD) method. The purity of β-TCP powders were determined from XRD pattern while the crystallite size of β-TCP powders were calculated by using Scherrer equation. Results shows that the purity of β-TCP powders were ranged from 20.33 % to 81.94 % while the crystallite size of β- TCP powders were ranged from 0.04391 μm to 0.06751 μm. From this work, particle size of CaCO3 will influenced the purity but not the mean crystallite size of synthesized β-TCP.
The land area of Tanah Putih, Gua Musang, Kelantan (Malaysia) is well-known for its wealth in industrial mineral resources, especially aluminosilicate of feldspar and mica. Natural feldspar and mica were physicochemically characterized with regard to X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscopy (TEM) techniques for qualitative and quantitative identification of feldspar and mica. They show a good crystallinity, high surface area and uniformity of mesoporous structures. For the purpose of this experiment, the aluminosilicate of feldspar was modified either by acid treatment, or grafting the silanol groups present with various functional groups including aminopropyl-, octyl-, vinyl-, mercapto- and glycidoxy-triethoxysilanes, or activation of pre-treated support with glutaraldehyde. These support derivatives were used for further utilization in the immobilization of lipase from Candida rugosa and resulted in various interaction mechanisms between enzyme and introduced supports. It seemed that the features of the functionalized feldspar surfaces provide a preferable environmental host to enable the adsorption of lipase via interfacial adsorption method. Lipase immobilization onto feldspar support were further confirmed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray microanalysis (EDX), transmission electron microscopy (TEM) and infra-red spectroscopy (FTIR) techniques. Enhancement of protein loading (up to 8.22 mg protein/g support) and immobilization yield (up to 78%) were shown by modified feldspar-lipase derivatives compared to unmodified feldspar support.
A study was carried out to determine short term diurnal radon concentration at five locations in Malaysia. Two locations (KG & AP) are former tin mining areas that has been converted to housing area and training centre respectively, one a relatively new city (SA), that was formerly a rubber and oil palm plantation area, one older cities (KB) and one housing complex by the sea (LP). The study was carried out in 2005, 2006 and 2007 using a diffused-junction photodiode sensor continuous radon monitor. The monitor is recognized by the USEPA. In each location, measurements were carried out on at least ten sites. Former tin mining areas of KG and AP shows up to seven times higher indoor average than the average in the other three locations. However the indoor average in all locations is still below the action level of 4 pCiL-1. For outdoor, the former tin mining areas average concentration was higher than the global average of 0.4 pCiL-1. For the twenty four hours temporal variation the trend indicated that former tin mining areas concentration are always higher, and at time up to six fold higher. The hourly variation of all locations follows an identical trend of high concentration during early to late morning and drop in the afternoon till evening. The outdoor twenty four hour temporal average of former tin mining areas is consistently higher than the outdoor global average of 0.4 pCiL-1. The strong correlation between indoor and outdoor concentration at AP, indicates that indoor radon might originates from outdoor environment. The study was also extended to estimate the effective dose (mSvyr-1) of Rn-222 to the public.
The purpose of this study is to measure and monitor the radon concentration from fabricated foamed light concrete, made of Portland cement, mine sand and granite. The concentration of radon released was measured using Radon Monitor Model 1027 from Sun Nuclear. The results of this research showed that the avearge radon concentration from foamed light concrete was 2.2 pCiL-1 L. Higher radon concentrations were detected after three days of measurements. Environment Protection Agency stated in its guidelines that radon concentration must lower than 4 pCiL-1 for a healthy environment. Thus, the use of foamed light concrete can be one of the alternatives to reduce radon concentration levels in human environment.
Indialite or α-cordierite was synthesized by glass crystallization method using mainly talc and kaolin and with small amount of MgO, Al2O3, SiO2 to compensate the chemical formulation of non-stoihiometric compositions of cordierite. (3MgO.1.5Al2O3.5SiO2). B2O3, P2O5 and CaO was also added to decrease the melting and sintering temperature of cordierite. The glasses were pelletized and sintered from 850 o C up to 1050 o C. Phase compositions of both heat treated glass was quantified by X-ray powder diffraction data by the Rietveld method using TOPAS Ver 3 software. Result shows that about 60wt% of α cordierite has successfully crystallized at 850 o C. Beside secondary phases (forsterite) which come from initial raw materials, phases from grinding media were also presents in the sample. The contamination was considered high since it has reacted with existence phases to form a new phase at higher temperature. Without any contamination from grinding it was expected to obtain more than 90wt% α cordierite using the same composition.
Chitosan was chemically modified with bulky structure, cis-5-norbornene-2, 3-dicarboxylic anhydride and the characteristic of this modified chitosan was studied. The resulting material was analyzed by FTIR, TGA, DSC, XRD and SEM to study the effect of N-acylation to the polysaccharide structure. FTIR results show that the anhydride monomer was successfully bound to amine group of chitosan. Thermal analysis of the modified structure provides the chitosan fibers with thermal stability while XRD and SEM show the lost of crystallinity of modified chitosan. XRD of modified chitosan shows broader peak pattern and a considerable increase in a dimension while SEM of chitosan presented the single particle morphology while norbornene-chitosan shows aggromolarate behaviour due to the hydrophobic nature of norbornene pendant group which induced aggromolaration of the particles in modified structure.
The term microfibril angle, MFA in wood science refers to the angle between the direction of the helical windings of cellulose microfibrils in the secondary cell wall, S2 layer of fibres and tracheids and the long axis of the cell. In this study, the mean MFA of the cell walls were determined for thin samples of thickness 200.0 µm from pith and outwards, for eight ages of Acacia mangium wood. The determination of MFA was based on a diffraction pattern arising from cellulose crystal planes of the type 002 generated by x-ray diffraction and recorded using an electronic detector. The results show an inversely relationship between MFA and age of tree in Acacia mangium wood. MFA decreased from 26.13° at age 3 year-old to 0.20° at tree of age 15 year-old for the pith region. The most significant drop occurred from 16.14° at age 7 yearold to 11.30° at age 9 year-old. An inversely relationship between MFA and storage modulus E’ was evidence in Acacia mangium at age 10-year-old. The results showed that about 76.22% variation of loss modulus E” was attributed to the MFA, while about 66.4% of the variation of glass transition Tg was explained by MFA under the same experimental conditions.