Thermoplastic natural rubber sample is found isotropic based on Small Angle X-Ray Scattering (SAXS) pattern. Morphological interpretation was deduced based on ideal lamellar morphology using 1-D correlation function. The fitting was carried out using Porod tail model and Vonk for backextrapolated model. It is found that the long period value is 15. 7nm which is comparable to results obtained from Lorenzt corrected profile, 20nm. Crystalline thickness and amorphous thickness was found as 13.4 and 2.31nm respectively.
Thorium is a fertile material that can undergo transmutation for it to become a fissile material,
uranium-233. The fissile material can go through a fission process in order to generate heat energy
and eventually electricity. Most nuclear reactors use uranium as their fission source. The use of
thorium as nuclear fuel has been only investigated for few types of reactors such as a high, temperature
gas reactor (HTGR), fast breeder reactor, light water reactor (LWR) and heavy water reactor
(HWR). For research reactors specifically, there are limited academic publications related to the
la,test u.se of thorium. Hence, the main, interest, of this work is to compile and review the latest
academic publications related to the active use of thorium, for research reactors in particular. The
reviewed studies have been, divided into two categories which are experimented and simulation projects.
The experimental projects are a,bold the ongoing thorium fuel tests that have been carried out. in an
actual, research reactor. On the hand, the simulation work: is related to the computational analysis
performed in predicting the neutronic behaviour of thorium based fuel in research reactors. The
experimented study of thorium is currently active for the KAMINI research reactor. Additionally, most,
simulation works focus on finding criticality and neutron spectra.
Although the precise etiology of Glioblastoma multiforme (GBM, WHO grade IV) remains unknown, its progression
is believed to be driven by the accumulation of multiple genetic alterations. Here, we report a case of a patient who
developed GBM, and associated with dual alterations, particularly 4977-bp deletion in mtDNA (mtDNA4977) and
p.Arg132His (R132H) mutation in IDH1. A 35-year old Malaysian woman patient who primary diagnosed with astrocytoma WHO grade I and subsequently after four years developed a GBM, was detected with a mtDNA4977. This
deletion appears to be a sporadic mutation. Additionally, analysis of patient’s tumor tissue also found to harbor a heterozygous IDH1 R132H mutation. This represents the first case report of coexisting mtDNA4977 together with IDH1
R132H mutation in a Malaysian patient of GBM. The findings of dual alterations could be of therapeutic benefit if
these alterations were justified to be contributing to GBM growth and aggressiveness.
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.
Neutron aperture is one of the collimator components in a neutron radiography facility. The optimum design of neutron aperture is very importance in order to obtain largest L/D ratio with highest thermal neutron flux and low gamma-rays at the image plane. In this study, the optimization of neutron aperture parameters were done using Monte Carlo N-Particle Transport Code, version five (MCNP5). This code has a capability to simulate the neutron, photon, and electron or coupled of neutron/photon/electron transport, including the capability to calculate eigen values for critical system. The aperture parameters concerned in this study are the selection of best aperture material, aperture thickness, aperture position and aperture center hole diameter. In these simulations, vacuum beam port medium was applied.
Cement and concrete has been widely used as shielding material in reactor nuclear in order to minimize exposure to individuals. In this paper we present boron based concrete as neutron shielding for nuclear reactor applications. Concrete specimens with dimension of 10x10x10 cm were used and irradiated with neutron radiation of 252-californium. Characterization of physical, mechanical and radiation attenuation properties of concrete were carried out. The results show that the shielding performance is better than ordinary concrete. From the result, we confirmed that the performance of the concrete/boron carbide is suitable for practical use.
In order to prepare Malaysia to be nuclear ready, the Malaysian 1 MW TRIGA MARK II research
reactor (RTP) located at the Malaysian Nuclear Agency was premeditated with the aim to effectually
actualize the multitude areas of basic nuclear research, labor training and education. To meet the
modern safety standards, analyses of a strong interaction between the thermal-hydraulic system
behavior and the space-dependent neutron kinetics are needed as mere thermal-hydraulics codes are
said to be incapable to succeed the present safety standards. This could be achieved through the
coupling of neutronic and thermal-hydraulic codes of the reactor. Previous studies had shown that the
coupled codes are able to successfully be employed for the correlation between thermal-hydraulic
analysis and neutron kinetics at transient and steady state. In this study, the coupling was achieved
through MCNP and TRIGLAV codes for neutronic and thermal-hydraulic respectively. Core-15 of
RTP was modeled for both of the codes; hence calculating the criticality, analysis of power and
neutron flux distribution. The consistency and accuracy of the developed Core-15 MCNP model was
established by comparing calculations to the experimental results and TRIGLAV code. The criticality
predictions for both codes are in very good agreement with the experimental results. The core reached
its criticality after 66 fuels. The highest hot rod power peaking factor was found to be 1.28. The
results are conservative and can be applied to show the reliability of MCNP and TRIGLAV codes.
This work main aim is to study the analysis of slow neutrons which include thermal and
epithermal neutrons and also analysis on fast neutrons. The outcome from this work showed that
the comparison result between fast and slow neutrons. The safety assessment at reactor TRIGA
FUSFATI (RTF) is one of the main objectives of the work and there is a detailed discussion on it
which helped in accomplishing the task. Gamma Rays produced in this experiment was high and in
the experiment and it is realized that the shielding plays a vital role in the success of this
experiment which prevents all the radiations. From the results of the experiment it is realized that
these gamma rays are not suitable for the application of Boron Neutron Capture Therapy
(BNCT). However, these radiations are suitable for the application of Neutron Radiography (NR).
The study on this work will help in study of nuclear applications such as BNCT, NR, SANS etc.
These applications are using in medical and nuclear fields. The electronic device used in the
experiment to detect neutron is Neutron Spectrometer. The results from Neutron Spectrometer
and TLDs are very similar which showed that the experiment is a success. Numerical results were
compared with those available in literature for validation.
Alumina powder was synthesized from an aluminum precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was of high purity and highly crystalline D-phase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder.
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.
Muhammad Akmal Asraf Mohamad Sharom, Zainol Abidin Ibrahim, Wan Ahmad Tajuddin Wan Abdullah, Megat Harun Al Rashid Megat Ahmad, Faridah Mohamad Idris, Abdul Aziz Mohamed
Small angle neutron scattering (SANS) is used for probing the microstructure of materials in the range between 1-100 nm in dimension. The scattered neutrons from the target material were detected by a 128 x 128 array area sensitive, Helium gas-filled proportional counter, which is known as Position Sensitive Detector (PSD). The small angle neutron scattering (SANS) facility in Malaysian Nuclear Agency has been developed since 1995. The data acquisition system of this prototype facility consists of the two-dimensional Position Sensitive Detector (2D-PSD) and neutron monitor as a data grabber, TDC Histogram as a memory processing processor, two units of ORTEC 994 as a counter and timer and a computer as a data acquisition controller via GPIB interfacing protocol. This paper will describe on the development of GPIB interface for data acquisition of the SANS instrument on Windows based platform. The GPIB device interface and graphical user interface (GUI) for this data acquisition is developed using WaveMetrics Igor software.
Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. The use of boundary element analysis system (BEASY) has allowed cathodic protection (CP) interference to be assessed in terms of the normal current density, which is directly proportional to the corrosion rate. This paper was present the analysis of the galvanic corrosion between Aluminium and Carbon Steel in natural sea water. The result of experimental was validated with computer simulation like BEASY program. Finally, it can conclude that the BEASY software is a very helpful tool for
future planning before installing any structure, where it gives the possible CP interference on any nearby unprotected metallic structure.
The geometry of reactor core, thermal column, collimator and shielding system for BNCT application of TRIGA MARK II REACTOR were simulated with MCNP5 code. Neutron particle lethargy and dose were calculated with MCNPX code. Neutron flux in a sample located at the end of collimator after normalized to measured value (Eid Mahmoud Eid Abdel Munem, 2007) at 1 MW power was 1.06E8 n/cm2/s. According to IAEA (2001) flux of 1.00E9 n/cm2/s requires three hours of treatment. Few modifications were needed to get higher flux.
A Monte Carlo simulation of the Malaysian nuclear reactor has been performed using MCNP Version 5 code. The purpose of the work is the determination of the multiplication factor (k eff ) for TRIGA Mark II research reactor in Malaysia based on Monte Carlo method. This work has been performed to calculate the value of k eff for two cases, which are the control rod either fully withdrawn or fully inserted to construct a complete model of the TRIGA Mark II PUSPATI Reactor (RTP). The RTP core was modeled as close as possible to the real core and the results of k eff from MCNP5 were obtained. When the control-fuel rods were fully inserted, the k eff value indicates the RTP reactor was in the subcritical condition with a value of 0.98370 ± 0.00054. When the control-fuel rods were fully withdrawn the value of k eff value indicates the RTP reactor is in the supercritical condition, that is 1.10773 ± 0.00083.
The temperature profile of a cryogenic system for cooling of beryllium filter of a small-angle neutron scattering (SANS) instrument of TRIGA MARK II PUSPATI research reactor was investigated using computational fluid dynamics (CFD) modeling and simulation. The efficient cooling of beryllium filter is important for obtaining higher cold neutron transmission for the SANS instrument. This paper presents the transient CFD results of temperature distributions via the thermal link to the beryllium and simulation of heat
flux. The temperature simulation data are also compared with the experimental results for the cooling time and distribution to the beryllium.
Thermal neutron beam from thermal column was selected for a Boron Neutron Capture Therapy
(BNCT) system utilizing the Malaysian TRIGA MARK II reactor. Determination of shielding
materials for fast and epithermal neutron was conducted. The materials selected were polyethylene,
paraffin and water. For gamma-ray shielding, lead was used. The objective of this paper is to present
the simulation and verification of an optimal design of BNCT collimation at a beam. line viewing the
thermal column. A collimator was made from polyethylene pipe with 8 cm of diameter filled with
paraffin.
Glioblastoma, the most aggressive and malignant form of glioma, appears to be resistant to various chemotherapeutic agents. Hence, approaches have been intensively investigated to targeti specific molecular pathways involved in glioblastoma development and progression. Aloe emodin is believed to modulate the expression of several genes in cancer cells. We aimed to understand the molecular mechanisms underlying the therapeutic effect of Aloe emodin on gene expression profiles in the human U87 glioblastoma cell line utilizing microarray technology. The gene expression analysis revealed that a total of 8,226 gene alterations out of 28,869 genes were detected after treatment with 58.6 μg/ml for 24 hours. Out of this total, 34 genes demonstrated statistically significant change (p<0.05) ranging from 1.07 to 1.87 fold. The results revealed that 22 genes were up-regulated and 12 genes were down-regulated in response to Aloe emodin treatment. These genes were then grouped into several clusters based on their biological functions, revealing induction of expression of genes involved in apoptosis (programmed cell death) and tissue remodelling in U87 cells (p<0.01). Several genes with significant changes of the expression level e.g. SHARPIN, BCAP31, FIS1, RAC1 and TGM2 from the apoptotic cluster were confirmed by quantitative real-time PCR (qRT-PCR). These results could serve as guidance for further studies in order to discover molecular targets for the cancer therapy based on Aloe emodin treatment.
Mitochondria are cellular machines essential for energy production. The biogenesis of mitochondria is a highly complex and it depends on the coordination of the nuclear and mitochondrial genome. Mitochondrial DNA (mtDNA) mutations and deletions are suspected to be associated with carcinogenesis. The most described mtDNA deletion in various human cancers is called the 4977-bp common deletion (mDNA4977) and it has been explored since two decades. In spite of that, its implication in carcinogenesis still unknown and its predictive and prognostic impact remains controversial. This review article provides an overview of some of the cellular and molecular mechanisms underlying mDNA4977 formation and a detailed summary about mDNA4977 reported in various types of cancers. The current knowledges of mDNA4977 as a prognostic and predictive marker are also discussed.
Glioblastoma multiforme (GBM) is one of the most common primary brain tumours in adults, accounting for almost 65% of all cases. Among solid tumours, GBM is characterised by strong angiogenesis, including the highest degree of vascular proliferation and endothelial cell hyperplasia. Despite numerous improvements in existing treatment approaches, the prognosis of GBM patients remains poor, with a mean survival of only 14.6 months. Growing evidence has shown significant overexpression of the ephrin type-A receptor 2 (EphA2) receptor in various malignancies, including GBM, as well as a correlation to poor prognoses. It is believed that EphA2 receptors play important roles in mediating GBM tumourigenesis, including invasion, metastasis, and angiogenesis. Despite the clinical and pathological importance of tumour-associated vasculature, the underlying mechanism involving EphA2 is poorly known. Here, we have summarised the current knowledge in the field regarding EphA2 receptors' roles in the angiogenesis of GBM.
The new millennium has been regarded as a genomic era. A lot of researchers and pathologists are beginning to understand the scientific basis of molecular genetics and relates with the progression of the diseases. Central nervous system (CNS) tumours are among the most rapidly fatal of all cancers. It has been proposed that the progression of malignant tumours may result from multi-step of genetic alterations, including activation of oncogenes, inactivation of tumour suppressor genes and also the presence of certain molecular marker such as telomerase activity. In this paper, we review some recent data from the literature, including our own studies, on the molecular genetics analysis in CNS tumours. Our studies have shown that two types of tumour suppressor genes, p53 and PTEN were involved in the development of these tumours but not in p16 gene among the patients from Hospital Universiti Sains Malaysia (HUSM). Telomerase activity also has been detected in various types of CNS tumours. Thus, it is important to assemble all data which related to this study and may provide as a vital information in a new approach to neuro-oncology studies in Malaysia.