Kaolin, theoretically known as having low reactivity during geopolymerization, was used as a source of aluminosilicate materials in this study. Due to this concern, it is challenging to directly produce kaolin geopolymers without pre-treatment. The addition of ground granulated blast furnace slag (GGBS) accelerated the geopolymerization process. Kaolin-GGBS geopolymer ceramic was prepared at a low sintering temperature due to the reaction of the chemical composition during the initial stage of geopolymerization. The objective of this work was to study the influence of the chemical composition towards sintering temperature of sintered kaolin-GGBS geopolymer. Kaolin-GGBS geopolymer was prepared with a ratio of solid to liquid 2:1 and cured at 60 °C for 14 days. The cured geopolymer was sintered at different temperatures: 800, 900, 1000, and 1100 °C. Sintering at 900 °C resulted in the highest compressive strength due to the formation of densified microstructure, while higher sintering temperature led to the formation of interconnected pores. The difference in the X-ray absorption near edge structure (XANES) spectra was related to the phases obtained from the X-ray diffraction analysis, such as akermanite and anothite. Thermal analysis indicated the stability of sintered kaolin-GGBS geopolymer when exposed to 1100 °C, proving that kaolin can be directly used without heat treatment in geopolymers. The geopolymerization process facilitates the stability of cured samples when directly sintered, as well as plays a significant role as a self-fluxing agent to reduce the sintering temperature when producing sintered kaolin-GGBS geopolymers.
Ultraviolet (UV) photodetectors (PDs) based on high-quality well-aligned ZnO nanorods (NRs) were fabricated using both modified and conventional chemical bath deposition (CBD) methods. The modified chemical bath deposition (M-CBD) method was made by adding air bubbles to the growth solution during the CBD process. The viability and effectiveness of M-CBD were examined by developing UV PDs based on ZnO NRs. The ZnO nano-seed layer was coated on a glass substrate utilizing radiofrequency (RF) sputtering. The impact of the different growth-times on morphology, growth rate, crystal structure, and optical and chemical properties were investigated systematically using different characterization techniques, such as field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) analysis, UV-VIS double beam spectrometer, and energy dispersive X-ray analysis (EDX), respectively. The Al/ZnO UV PDs based on ZnO nanorods were fabricated with optimum growth conditions through the two methods of preparation. This study showed that the synthesized ZnO NRs using the M-CBD method for different growth times possess better properties than the conventional method under similar deposition conditions. Despite having the highest aspect ratio and growth rate of ZnO NRs, which were found at 4 h growth duration for both methods, the aspect ratio of ZnO NRs using the M-CBD technique was comparatively higher than the conventional CBD method. Besides, the UV PDs fabricated by the M-CBD method at 5 V bias voltage showed high sensitivity, short response time, quick recovery time, high gain, low dark current, and high photocurrent compared with the UV PD device fabricated by the conventional CBD method.
Pseudotumour of the lung is a rare chest x-ray finding among patients who present with fluid overload. It is caused by loculated pleural effusion in the lung fissures. Unfortunately, the occurrence of pseudotumour can be misleading and sometimes can lead to unnecessary investigation and emotional stress to the patient. We present here a case of a 61-year-old gentleman with a known history of hypertension, diabetes mellitus and dyslipidemia who presented at University Malaya Medical Centre with symptoms of fluid overload and a right middle lobe mass on chest x-ray. The right middle lobe mass disappeared entirely after being treated with aggressive diuretic therapy. A diagnosis of pseudotumour was made and described in this case report.
Nanotechnology is one of the most interesting areas of research due to its flexibility to improve or form new products from nanoparticles (NPs), and as a fast, greener, more eco-friendly and sustainable solution to technological and environmental challenges. Among metal oxides of photocatalytic performance, the use of titania (TiO2) as photocatalyst is most popular due to its unique optical and electronic properties. Despite the wide utilization, the synthesis of TiO2 NPs bears many disadvantages: it utilizes various less environmental-friendly chemicals, high cost, requires high pressure and energy, and potentially hazardous physical and chemical methods. Hence, the development of green synthesis approach with eco-friendly natural products can be used to overcome these adverse effects. In this work, TiO2 NPs have been prepared by using Deinbollia pinnata leaves extracts, obtained by different solvents (n-hexane, ethyl acetate, and ethanol) with different polarities. The extracts acted as the reducing agent, while titanium isopropoxide as the precursor and water as the solvent. X-ray diffraction (XRD) pattern confirmed the synthesized TiO2 consist of anatase phase in high purity, with average crystallite size in the range of 19-21 nm. Characterization by using field emission scanning electron microscopy (FESEM) showed the TiO2 NPs possess a uniform semi-spherical shape in the size range of 33-48 nm. The energy dispersive X-ray (EDX) spectra of green TiO2 NPs showed two peaks for the main elements of Ti (61 Wt.%) and O (35 Wt.%). The band-gap energy of 3.2 eV was determined using UV-Vis spectroscopy. From the nitrogen sorption analysis, type V isotherm of the material was obtained, with BET surface area of 31.77 m2/g. The photocatalytic activity of synthesized TiO2 was evaluated for photodegradation of methyl orange (MO) under UV light irradiation. Based on the results, it is shown that TiO2 NPs synthesized with D. pinnata leaves extracted using ethyl acetate showed the most effective photodegradation performance, achieving 98.7% of MO conversion within 150 min. It can be concluded that the use of plant extracts in synthesis with TiO2 managed to produce highly crystalline anatase TiO2 with superior photocatalytic activity in the photodegradation of organic dye.
Despite the importance of studying the instability of delithiated cathode materials, it remains difficult to underpin the degradation mechanism of lithium-rich cathode materials due to the complication of combined chemical and structural evolutions. Herein, we use state-of-the-art electron microscopy tools, in conjunction with synchrotron X-ray techniques and first-principle calculations to study a 4d-element-containing compound, Li2Ru0.5Mn0.5O3. We find surprisingly, after cycling, ruthenium segregates out as metallic nanoclusters on the reconstructed surface. Our calculations show that the unexpected ruthenium metal segregation is due to its thermodynamic insolubility in the oxygen deprived surface. This insolubility can disrupt the reconstructed surface, which explains the formation of a porous structure in this material. This work reveals the importance of studying the thermodynamic stability of the reconstructed film on the cathode materials and offers a theoretical guidance for choosing manganese substituting elements in lithium-rich as well as stoichiometric layer-layer compounds for stabilizing the cathode surface.
Poly(phenyl-(4-(6-thiophen-3-yl-hexyloxy)-benzylidene)-amine) (P3TArH) was successfully synthesized and coated on the surface of Fe₃O₄ magnetic nanoparticles (MNPs). The nanocomposites were characterized by Fourier transform infra-red (FTIR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, analyzer transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). P3TArH-coated MNPs (MNP@P3TArH) showed higher capabilities for the extraction of commonly-used phthalates and were optimized for the magnetic-solid phase extraction (MSPE) of environmental samples. Separation and determination of the extracted phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), dicyclohexyl phthalate (DCP), di-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DNOP), were conducted by a gas chromatography-flame ionization detector (GC-FID). The best working conditions were as follows; sample at pH 7, 30 min extraction time, ethyl acetate as the elution solvent, 500-µL elution solvent volumes, 10 min desorption time, 10-mg adsorbent dosage, 20-mL sample loading volume and 15 g·L-1 concentration of NaCl. Under the optimized conditions, the analytical performances were determined with a linear range of 0.1⁻50 µg·L-1 and a limit of detection at 0.08⁻0.468 µg·L-1 for all of the analytes studied. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSD%) of three replicates were each demonstrated in the range of 3.7⁻4.9 and 3.0⁻5.0, respectively. The steadiness and reusability studies suggested that the MNP@P3TArH could be used up to five cycles. The proposed method was executed for the analysis of real water samples, namely commercial bottled mineral water and bottled fresh milk, whereby recoveries in the range of 68%⁻101% and RSD% lower than 7.7 were attained.
Introduction: Various phantom with varied materials has been proposed to replace the human body. Besides, there is always a demand to use the local material as a phantom material, which is readily available and inexpensive. Wood is usually preferred because it is multifunction, environmentally friendly, low in toxic, inexpensive, as well as easy to use and prepare. Previous studies have found that Rhizophora spp. is a suitable natural source material and has been suggested due to its comparable dosimetric properties to commercial phantom. Methods: In this study, fabricated Rhizophora spp. particleboards phantom was opted as a solid-equivalent phantom medium at low energy photon beams using Gafchromic film x-ray quality assurance 2 (XRQA2). Additionally, the characteristics of XRQA2 film in the diagnostic energy range were generated. Results: Interestingly, the density of the fabricated Rhizophora spp particleboards was observed to have the same density with the water equivalent material (ρ= 1.00 g.cm-3) and has shown to have loosened agreement with PDD of water phantom at approximately 25% of the dose error. Also, further analysis using XRQA 2 film showed that energy was independent at different ranges. Conclusion: The analysis of fabricated Rhizophora spp particleboards undertaken here has extended our knowledge of the possibility of man- ufacturing cost-effective water equivalent phantom by using binder-less particleboard from Rhizophora spp. There- fore, a definite need for smaller interspacing particles should be considered to elevate the potential of Rhizophora spp particle boards as water equivalent materials.
Chest radiography, or chest X-ray (CXR), is not only an important tool for triaging and screening for pulmonary tuberculosis (TB) but is also useful in aiding diagnosis when pulmonary TB cannot be confirmed bacteriologically. Sabah is a state with high TB burden with the incidence rate of 124/100,000 population in 2015. Access to chest radiography is limited in many settings in Sabah. In 2016, the TB and Leprosy Control Unit of Sabah State Health Department started systematic screening for TB with the help of a mobile digital X-ray unit.
The aimed of this study is to estimate the entrance surface dose (ESD) of routine chest X-ray (CXR) examination and to compare the direct and indirect measurement. This study also extended to relate with the patients body thickness and established lifetime attributable risk (LAR) of the examinations. A total of 101 CXR examinations in posteroanterior (PA) projections were selected
as subjects and data, such as patient habitus and scanning acquisition parameters were recorded. The mean ESD value obtained from the TLD-100 and the software calculation was 0.31 mGy and 0.17 mGy, respectively. The percentage deviation obtained ranged from 25.5% to 61.3%. In comparison with the national diagnostic reference level (DRL), the mean values of ESD obtained from this study were lower by a factor of 3. Furthermore, it was observed that the mean absorbed dose of the adrenals, kidneys, lungs, oesophagus, and heart walls were lower as compared to the ESD value. The examinations were only associated with very low risk of cancer incidence and mortality. Hence, the results of this study suggested a need for standardisations of the personnel training to perform X-ray examinations according to ALARA principles.
This paper clarified the microstructural element distribution and electrical conductivity changes of kaolin, fly ash, and slag geopolymer at 900 °C. The surface microstructure analysis showed the development in surface densification within the geopolymer when in contact with sintering temperature. It was found that the electrical conductivity was majorly influenced by the existence of the crystalline phase within the geopolymer sample. The highest electrical conductivity (8.3 × 10-4 Ωm-1) was delivered by slag geopolymer due to the crystalline mineral of gehlenite (3Ca2Al2SiO7). Using synchrotron radiation X-ray fluorescence, the high concentration Ca boundaries revealed the appearance of gehlenite crystallisation, which was believed to contribute to development of denser microstructure and electrical conductivity.
G protein-coupled receptors (GPCRs) belong to the largest family of protein targets comprising over 800 members in which at least 500 members are the therapeutic targets. Among the GPCRs, G protein-coupled estrogen receptor-1 (GPER-1) has shown to have the ability in estrogen signaling. As GPER-1 plays a critical role in several physiological responses, GPER-1 has been considered as a potential therapeutic target to treat estrogen-based cancers and other non-communicable diseases. However, the progress in the understanding of GPER-1 structure and function is relatively slow due to the availability of a only a few selective GPER-1 modulators. As with many GPCRs, the X-ray crystal structure of GPER-1 is yet to be resolved and thus has led the researchers to search for new GPER-1 modulators using homology models of GPER-1. In this review, we aim to summarize various approaches used in the generation of GPER-1 homology model and their applications that have resulted in new GPER-1 ligands.
Indium antimonide nanowires were synthesized by electrochemical deposition using anodic aluminum oxide template in the presence of gold film as conductive layers. Field emission scanning electron microscopy and energy dispersive X-ray spectrometry measurements were carried out to investigate the effect of adhesive insulated tape covered below the conductive layer. Results showed that the anodic aluminum oxide template covered with insulating tapes had better morphology with less presence of overgrown rough film on the topside of the anodic aluminum oxide template and it exhibited a smoother nanowire sidewall as compared to the uncovered ones. Additionally, the unique properties of anodic aluminum oxide were controllable pore diameter with a narrow size distribution at some intervals. It was evident from the energy dispersive X-ray spectrum that the nanowires synthesized from the covered template condition exhibited better InSb composition and stoichiometric ratio compared to the uncovered template condition.
This paper addresses the growth of nano-structured MgZnO thin films by sol-gel spin coating method which will be used as a template layer to grow carbon nanotubes. The nano-structured MgZnO films were deposited on platinized (100) silicon substrates. In this work, we focused on the effect of aging and Mg content on the film structure and resistivity. Sols with Mg content of 10, 30 and 50 at.% were subjected to aging times of between 3 to 240 hours. Results from scanning (SEM) and field emission scanning electron (FESEM) microscopes and surface profiler (SP) showed that the sol aging increased the thickness, grain size and surface roughness for aging up to 240 hours. The energy dispersive analysis by X-ray (EDAX) confirmed the element of Mg in the ZnO films. The electrical resistivity also increased with aging time as confirmed by four point probe method. The results suggest that appropriate aging of the sol is important for improving physical quality and electrical performance of MgZnO thin films derived from sol-gel technique.
Zinc oxide (ZnO) is an emerging optoelectronic material in large area electronic applications due to its various functional behaviors. We present the fabrication and the characterization of ZnO nanorods. The ZnO nanorods were synthesized using sol-gel hydrothermal technique on oxidized silicon substrates. Different post-annealing temperatures were explored in the sol-gel hydrothermal synthesis of the ZnO nanorods. The surface morphology of the ZnO nanorods were examined using scanning electron microscope (SEM). In order to investigate the structural properties, the ZnO nanorods were measured using X-ray diffractometer (XRD). The optical properties were measured using ultraviolet-visible (UV-Vis) spectroscopy. The influence of the post-annealing temperature on the realized ZnO nanorods will be revealed and discussed in this paper.
Zinc oxide (ZnO) is an emerging material in large area electronic applications such as thin-film solar cells and transistors. We report on the fabrication and characterization of ZnO microstructures and nanostructures. The ZnO microstructures and nanostructures have been synthesized using sol-gel immerse technique on oxidized silicon substrates. Different precursor's concentrations ranging from 0.0001 M to 0.01 M (M=molarity) using zinc nitrate hexahydrate [Zn(NO3)2. 6H2O] and hexamethylenetetramine [C6H12N4] were employed in the synthesis of the ZnO structures. The surface morphologies were examined using scanning electron microscope (SEM) and atomic force microscope (AFM). In order to investigate the structural properties, the ZnO microstructures and nanostructures were measured using X-ray diffractometer (XRD). The optical properties of the ZnO structures were measured using photoluminescence (PL) and ultraviolet-visible (UV-Vis) spectroscopies.
Pencirian enzim ekstraselular protease daripada bakteria Alkalophilic Bacillus lehensis G1 dari Malaysia telah dikaji. Enzim protease yang dirembeskan diuji pada agar susu skim 2%. Keputusan menunjukkan protease ekstraselular mampu mengekalkan aktiviti sehingga suhu 60°C di dalam julat pH yang luas iaitu 3 hingga 11 dengan suhu optimum pada 40°C dan pH optimum pada 7.0. Aktiviti enzim juga diperhatikan akan meningkat dengan penambahan beberapa ion iaitu Mn2+, Fe2+, Cu2+, Mg2+ dan Co2+. Manakala aktiviti protease didapati sedikit direncat dengan kehadiran ion Ca2+, K+ dan Ni2+ dengan baki aktiviti sebanyak 85%, 81% dan 75%. Protease ekstraselular juga didapati serasi dengan beberapa cecair detergen komersial dari Malaysia, yang menunjukkan protease ini boleh dimanfaatkan sebagai pembersih kotoran pada pakaian. Selain itu, potensi kegunaan protease yang dihasilkan oleh B. lehensis G1 ke atas penguraian gelatin dari filem X-ray yang telah digunakan juga telah dilakukan di dalam kajian ini.
Being an imperative material for man either used as building materials, pottery or as components in material industry and technology, knowledge of clays elemental contents is important. In the present study ten clay samples obtained from various locations in North-West Peninsular Malaysia were used. Majority of the clays were economically manufactured to be used as building materials or pottery. The objective of study was to determine the main elemental contents of the samples, and relate the results to the types of minerals, as well as to compare them with clays from other studies. In the study X-ray Fluorescence (XRF) coupled to samples dilution method and standard calibration samples was used. The elements detected in the study were Si, Al, Fe, Ti, K and Ca. Depending on locations, the percentage concentration ranged between 24.8 – 32.4 for Si, 10.8 – 19.0 for Al, 0.09 – 2.12 for Fe, 0.08 – 1.13 for Ti, 0.45 – 3.39 for K and trace amount of Ca and P. However, Mg that normally found in typical clay was not found in the studied samples. Comparing the oxide of the major elements with other studies, it was found that the clay samples contained mixtures of kaolinite (two-layered structure) and illite (three-layered structure).
Ni3A1 is an intermetallic compound which has unique property with temperature. Annealing is done at temperature 300, 500, and 700°C for 1 hour and analyzed with X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX) analysis for their crystallographic nature. EDX confirmed the composition of Ni3A1 with exact stoichiometry, whereas the XRD confirmed the crystallographic nature of the material. The mechanical properties by hardness results showed that Ni3A1 has highest Vickers hardness value of 554 HV when it is non-heat treated. Its hardness drops as it undergoes annealing process. Corrosion analysis by tafel test shows that its polarization resistance may increase up to 4145 W cm2 when annealed at high temperature. These results show that Ni3A1 is a promising material to be considered as an alternative automotive body.
Aim: This study was designed to evaluate the use of ultrasound in diagnosis of infection and tumour of long bones. Methodology: Patients referred from the orthopaedic unit with doubt regarding long bone clinical and/or radiological signs which could be tumour or infection were enrolled in this study. Analysis of ultrasound characteristics included presence of pericortical fluid over normal cortex well away from the primary lesion, wavy contour sign (fluid tracking in and out muscle planes), subperiosteal fluid and soft tissue mass displacing adjacent muscle planes. Results: Fourteen out of 15 patients with confirmed osteomyelitis were diagnosed by ultrasound examination. Ultrasound as a diagnostic tool has a sensitivity of 93% and specificity of 100%. The most accurate indicator was pericortical fluid noted up to several centimetres from the long bone abnormality seen on plain x-rays. Conclusion: Ultrasound is a safe, fast, cost-effective imaging modality that can play an important role in diagnosis of osteomyelitis as it then serves as a tool for ultrasound guided aspiration.
Considerable amount of uranium and thorium are found in our local zircon and the level is much higher than the maximum value adopted by Malaysia and many importing countries. Energy Dispersive X-ray Flourescence (EDXRF) proves to be a very valuable tool in the determination of these radioactive elements as it can perform the analysis simultaneously in shorter time. Quantitative analysis of this mineral involves the use of a fundamental parameter technique developed by National Bureau of Standard, USA and Geological Survey Canada (NBS-GSC FPT). The analysis for tin slag is more challenging as there is no reference standard of similar material. Thus the standard addition method was applied to correct the error from the matrix of the sample.