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Fulltext Use of Adjuvant Endocrine Therapy Among Post-Menopausal Breast Cancer Patients in Malaysia

Saiful Bahri A, Tuan Mahmood TM, Abdul-Aziz SA, Makmor-Bakry M, Mohamed Shah N

Patient Prefer Adherence, 2021;15:227-235.
PMID: 33568899 DOI: 10.2147/PPA.S293029

Context: Globally, breast cancer is the most common cancer affecting women, and adjuvant endocrine therapy (AET) is part of its treatment modality, which improves patients' outcome. However, there are concerns on side effects related to its use, which may affect treatment adherence.
Purpose: This study was conducted to explore attitude and practice on using AET among breast cancer patients in Malaysia.
Patients and Methods: Postmenopausal breast cancer patients on at least 3 months of AET attending the outpatient oncology clinic at a tertiary care hospital were interviewed. Patients underwent in-depth interviews exploring their attitude and practices while on AET using a semi-structured interview guide. The interviews were transcribed verbatim and analyzed using thematic analysis.
Results: There were four main themes for attitude toward the use of AET: 1) benefits of using AET, 2) concerns on taking AET, 3) beliefs on alternative treatment, and 4) beliefs toward the doctor. For practice, six themes were obtained: 1) correct use of AET, 2) appointment adherence, 3) information-seeking behavior, 4) counseling services obtained, 5) experienced side effects of AET, and 6) usage of complementary and alternative medicines.
Conclusion: Several themes concerning attitude and practice of breast cancer patients receiving AET were identified, which may be addressed during treatment consultations in clinical practice.
Fulltext Thermal Stability and Rheological Properties of Epoxidized Natural Rubber-Based Magnetorheological Elastomer

Yunus NA, Mazlan SA, Ubaidillah, Abdul Aziz SA, Tan Shilan S, Abdul Wahab NA

Int J Mol Sci, 2019 Feb 10;20(3).
PMID: 30744210 DOI: 10.3390/ijms20030746

Determination of the thermal characteristics and temperature-dependent rheological properties of the magnetorheological elastomers (MREs) is of paramount importance particularly with regards to MRE applications. Hitherto, a paucity of temperature dependent analysis has been conducted by MRE researchers. In this study, an investigation on the thermal and rheological properties of epoxidized natural rubber (ENR)-based MREs was performed. Various percentages of carbonyl iron particles (CIPs) were blended with the ENR compound using a two roll-mill for the preparation of the ENR-based MRE samples. The morphological, elemental, and thermal analyses were performed before the rheological test. Several characterizations, as well as the effects of the strain amplitude, temperature, and magnetic field on the rheological properties of ENR-based MRE samples, were evaluated. The micrographs and elemental results were well-correlated regarding the CIP and Fe contents, and a uniform distribution of CIPs was achieved. The results of the thermal test indicated that the incorporation of CIPs enhanced the thermal stability of the ENR-based MREs. Based on the rheological analysis, the storage modulus and loss factor were dependent on the CIP content and strain amplitude. The effect of temperature on the rheological properties revealed that the stiffness of the ENR-based MREs was considered stable, and they were appropriate to be employed in the MRE devices exposed to high temperatures above 45 °C.
Fulltext The effect of salt water ageing on the mechanical and rheological properties of magnetorheological elastomer

Ahmad Khairi MH, Mazlan SA, Ubaidillah U, Khaidir REM, Nordin NA, Johari MAF, et al.

Sci Rep, 2023 Apr 10;13(1):5810.
PMID: 37037883 DOI: 10.1038/s41598-023-33171-6

This paper aims to investigate the mechanical and rheological properties of magnetorheological elastomer (MRE) in marine ecosystems. The prepared samples comprised silicone rubber (SR) and 70 wt% micron-sized carbonyl iron particles (CIPs), immersed in an artificial marine ecosystem using salt water (Natrium Chloride) for 30 days. The mechanical properties of MRE samples were evaluated using hardness and quasi-static tensile tests. While the rheometer was used to investigate the rheological properties of their storage modulus condition with magnetic field stimulation. Further analysis of the defects and damages caused by salt water ageing was done through morphological observation using scanning electron microscope (SEM) technology. The results showed that the hardness and tensile strength of MRE samples that were soaked in salt water were affected over time. Lower values of hardness and tensile strength were obtained after 30 days due to the presence of Na+ and Cl-, which acted as an accelerator to the hydrolyzation process of the MRE. The process then, enhanced the water ingress capability into the matrix to cause the molecular changes. Interestingly, for rheological properties, 30 days of salt water ageing allowed the water molecules to move the MRE matrix molecular chains apart, a process known as plasticization and thus increasing the MR effect. Furthermore, morphological evidence was established to determine the MRE changes during salt water ageing. The research findings should greatly contribute to a better understanding of the effect of salt water on the performance of MRE.
Fulltext The Effect of Particle Shapes on the Field-Dependent Rheological Properties of Magnetorheological Greases

Mohamad N, Ubaidillah, Mazlan SA, Choi SB, Abdul Aziz SA, Sugimoto M

Int J Mol Sci, 2019 Mar 27;20(7).
PMID: 30934679 DOI: 10.3390/ijms20071525

The transient response of magnetorheological (MR) materials, in general, is very important for design consideration in MR-based devices. Better response to magnetic fields is beneficial for a better response rate to the electrical current applied in the electromagnetic coil. As a result, MR-based devices would have a high response to external stimuli. In this work, the principal characteristics of magnetorheological greases (MRGs) which have two different particle shapes are experimentally investigated. One type of particle distributed in the grease medium is conventional spherical-shaped carbonyl iron (CI) particles, while the other is plate-like CI particles made using a high-energy rotary ball mill from spherical CI particles. A set of bidisperse MRG samples are firstly prepared by adjusting the weight percentage of the plate-like CI particles and mixing with the spherical CI particles. Subsequently, three important properties of MRGs in terms of their practical application are measured and compared between the two different particle shapes. The field-dependent apparent viscoelastic properties of the prepared MRG samples are measured, followed by the field-dependent storage and loss moduli using an oscillatory shear rheometer. In addition, the transient response time, which indicates the speed in the actuating period of MRGs, is measured by changing the strain amplitude. Then, a comparative assessment on the three properties are undertaken between two different particle shapes by presenting the corresponding results in the same plot. It is shown that the bidisperse MRG with plate-like CI particles exhibits an increase in the initial apparent viscosity as well as stiffness property compared to the MRG with spherical particles only.
Fulltext The Effect of Graphite Additives on Magnetization, Resistivity and Electrical Conductivity of Magnetorheological Plastomer

Zaini N, Mohamad N, Mazlan SA, Abdul Aziz SA, Choi SB, Hapipi NM, et al.

Materials (Basel), 2021 Dec 06;14(23).
PMID: 34885641 DOI: 10.3390/ma14237484

Common sensors in many applications are in the form of rigid devices that can react according to external stimuli. However, a magnetorheological plastomer (MRP) can offer a new type of sensing capability, as it is flexible in shape, soft, and responsive to an external magnetic field. In this study, graphite (Gr) particles are introduced into an MRP as an additive, to investigate the advantages of its electrical properties in MRPs, such as conductivity, which is absolutely required in a potential sensor. As a first step to achieve this, MRP samples containing carbonyl iron particles (CIPs) and various amounts of of Gr, from 0 to 10 wt.%, are prepared, and their magnetic-field-dependent electrical properties are experimentally evaluated. After the morphological aspect of Gr-MRP is characterized using environmental scanning electron microscopy (ESEM), the magnetic properties of MRP and Gr-MRP are evaluated via a vibrating sample magnetometer (VSM). The resistivities of the Gr-MRP samples are then tested under various applied magnetic flux densities, showing that the resistivity of Gr-MRP decreases with increasing of Gr content up to 10 wt.%. In addition, the electrical conductivity is tested using a test rig, showing that the conductivity increases as the amount of Gr additive increases, up to 10 wt.%. The conductivity of 10 wt.% Gr-MRP is found to be highest, at 178.06% higher than the Gr-MRP with 6 wt.%, for a magnetic flux density of 400 mT. It is observed that with the addition of Gr, the conductivity properties are improved with increases in the magnetic flux density, which could contribute to the potential usefulness of these materials as sensing detection devices.
Fulltext Solvent Dependence of the Rheological Properties in Hydrogel Magnetorheological Plastomer

Hapipi NM, Mazlan SA, Ubaidillah U, Abdul Aziz SA, Ahmad Khairi MH, Nordin NA, et al.

Int J Mol Sci, 2020 Mar 05;21(5).
PMID: 32151055 DOI: 10.3390/ijms21051793

Chemically crosslinked hydrogel magnetorheological (MR) plastomer (MRP) embedded with carbonyl iron particles (CIPs) exhibits excellent magnetic performance (MR effect) in the presence of external stimuli especially magnetic field. However, oxidation and desiccation in hydrogel MRP due to a large amount of water content as a dispersing phase would limit its usage for long-term applications, especially in industrial engineering. In this study, different solvents such as dimethyl sulfoxide (DMSO) are also used to prepare polyvinyl alcohol (PVA) hydrogel MRP. Thus, to understand the dynamic viscoelastic properties of hydrogel MRP, three different samples with different solvents: water, DMSO, and their binary mixtures (DMSO/water) were prepared and systematically carried out using the oscillatory shear. The outcomes demonstrate that the PVA hydrogel MRP prepared from precursor gel with water shows the highest MR effect of 15,544% among the PVA hydrogel MRPs. However, the samples exhibit less stability and tend to oxidise after a month. Meanwhile, the samples with binary mixtures (DMSO/water) show an acceptable MR effect of 11,024% with good stability and no CIPs oxidation. Otherwise, the sample with DMSO has the lowest MR effect of 7049% and less stable compared to the binary solvent samples. This confirms that the utilisation of DMSO as a new solvent affects the rheological properties and stability of the samples.
Fulltext Rheological Performance of Magnetorheological Grease with Embedded Graphite Additives

Mohd Nasir NA, Nazmi N, Mohamad N, Ubaidillah U, Nordin NA, Mazlan SA, et al.

Materials (Basel), 2021 Sep 06;14(17).
PMID: 34501180 DOI: 10.3390/ma14175091

The use of highly viscous grease as a medium in magnetorheological grease (MRG) provides the benefit of avoiding sedimentation from occurring. However, it limits the expansion of yield stress in the on-state condition, thus reducing the application performance during operation. Therefore, in this study, the improvement in the rheological properties of MRG was investigated through the introduction of graphite as an additive. MRG with 10 wt % graphite (GMRG) was fabricated, and its properties were compared to a reference MRG sample. The microstructure of GMRG was characterized using an environmental scanning electron microscope (ESEM). The rheological properties of both samples, including apparent viscosity, yield stress, and viscoelasticity, were examined using a shear rheometer in rotational and oscillatory modes. The results demonstrated a slight increase in the apparent viscosity in GMRG and a significant improvement in yield stress by 38.8% at 3 A with growth about 32.7% higher compared to MRG from 0 to 3 A. An expansion of the linear viscoelastic region (LVE) from 0.01% to 0.1% was observed for the GMRG, credited to the domination of the elastic properties on the sample. These obtained results were confirmed based on ESEM, which described the contribution of graphite to constructing a more stable chain structure in the GMRG. In conclusion, the findings highlight the influence of the addition of graphite on improving the rheological properties of MRG. Hence, the addition of graphite in MRG shows the potential to be applied in many applications in the near future.
Fulltext Prevalence, risk factors and health outcomes associated with polypharmacy among urban community-dwelling older adults in multi-ethnic Malaysia

Lim LM, McStea M, Chung WW, Nor Azmi N, Abdul Aziz SA, Alwi S, et al.

PLoS One, 2017;12(3):e0173466.
PMID: 28273128 DOI: 10.1371/journal.pone.0173466

BACKGROUND: Polypharmacy has been associated with increased morbidity and mortality in the older population.
OBJECTIVES: The aim of this study was to determine the prevalence, risk factors and health outcomes associated with polypharmacy in a cohort of urban community-dwelling older adults receiving chronic medications in Malaysia.
METHODS: This was a baseline study in the Malaysian Elders Longitudinal Research cohort. The inclusion criteria were individuals aged ≥55years and taking at least one medication chronically (≥3 months). Participants were interviewed using a structured questionnaire during home visits where medications taken were reviewed. Health outcomes assessed were frequency of falls, functional disability, potential inappropriate medication use (PIMs), potential drug-drug interactions (PDDIs), healthcare utilisation and quality of life (QoL). Risk factors and health outcomes associated with polypharmacy (≥5 medications including dietary supplements) were determined using multivariate regression models.
RESULTS: A total of 1256 participants were included with a median (interquartile range) age of 69(63-74) years. The prevalence of polypharmacy was 45.9% while supplement users made up 56.9% of the cohort. The risk factors associated with increasing medication use were increasing age, Indian ethnicity, male, having a higher number of comorbidities specifically those diagnosed with cardiovascular, endocrine and gastrointestinal disorders, as well as supplement use. Health outcomes significantly associated with polypharmacy were PIMS, PDDIs and increased healthcare utilisation.
CONCLUSION: A significant proportion of older adults on chronic medications were exposed to polypharmacy and use of dietary supplements contributed significantly to this. Medication reviews are warranted to reduce significant polypharmacy related issues in the older population.
Fulltext Optimal energy for cell radiosensitivity enhancement by gold nanoparticles using synchrotron-based monoenergetic photon beams

Rahman WN, Corde S, Yagi N, Abdul Aziz SA, Annabell N, Geso M

Int J Nanomedicine, 2014;9:2459-67.
PMID: 24899803 DOI: 10.2147/IJN.S59471

Gold nanoparticles have been shown to enhance radiation doses delivered to biological targets due to the high absorption coefficient of gold atoms, stemming from their high atomic number (Z) and physical density. These properties significantly increase the likelihood of photoelectric effects and Compton scattering interactions. Gold nanoparticles are a novel radiosensitizing agent that can potentially be used to increase the effectiveness of current radiation therapy techniques and improve the diagnosis and treatment of cancer. However, the optimum radiosensitization effect of gold nanoparticles is strongly dependent on photon energy, which theoretically is predicted to occur in the kilovoltage range of energy. In this research, synchrotron-generated monoenergetic X-rays in the 30-100 keV range were used to investigate the energy dependence of radiosensitization by gold nanoparticles and also to determine the photon energy that produces optimum effects. This investigation was conducted using cells in culture to measure dose enhancement. Bovine aortic endothelial cells with and without gold nanoparticles were irradiated with X-rays at energies of 30, 40, 50, 60, 70, 81, and 100 keV. Trypan blue exclusion assays were performed after irradiation to determine cell viability. Cell radiosensitivity enhancement was indicated by the dose enhancement factor which was found to be maximum at 40 keV with a value of 3.47. The dose enhancement factor obtained at other energy levels followed the same direction as the theoretical calculations based on the ratio of the mass energy absorption coefficients of gold and water. This experimental evidence shows that the radiosensitization effect of gold nanoparticles varies with photon energy as predicted from theoretical calculations. However, prediction based on theoretical assumptions is sometimes difficult due to the complexity of biological systems, so further study at the cellular level is required to fully characterize the effects of gold nanoparticles with ionizing radiation.
Morphological features of magnetorheological elastomer degradation under a natural weathering environment

Johari MAF, Mazlan SA, Abdul Aziz SA, Zaini N, Nordin NA, Ubaidillah U, et al.

Sci Rep, 2024 Jan 12;14(1):1155.
PMID: 38212384 DOI: 10.1038/s41598-024-51736-x

It is well known in the field of materials science that a substance's longevity is significantly influenced by its environment. Everything begins with the initial contact on a material's surface. This influence will then deteriorate and have an extended negative impact on the strength of the material. In this study, the effect of natural weathering in tropical climates on magnetorheological elastomer (MRE) was investigated through microstructural evaluation to understand the aging behavior of the environmentally exposed MRE. To understand and elucidate the process, MREs made of silicone rubber and 70 wt% micron-sized carbonyl iron particles were prepared and exposed to the natural weathering of a tropical climate for 90 days. The MRE samples were then mechanically tensile tested, which revealed that Young's modulus increased, while elongation at break decreased. Surface degradation due to weathering was suspected to be the primary cause of this condition. Using scanning electron microscopy (SEM), the degradation of MRE was investigated as a function of morphological evidence. Upon examination through SEM, it was noted that the weathering effects on the morphology of the exposed samples showed distinct characteristics on the degraded surfaces of the MRE, including numerous microvoids, cavities, and microcracks. While these features were not prominent for the MRE itself, they bear resemblance to the effects observed in similar materials like rubber and elastomer. An atomic force microscope (AFM) is used to investigate the surface topography and local degradation conditions. This observation revealed a distinctive degradation characteristic of the MRE in connection to natural weathering in tropical climates. The surface damage of the MRE samples became severe and inhomogeneous during the environmental aging process, and degradation began from the exposed MRE surface, causing the mechanical characteristics of the MRE to significantly change.
Fulltext Material Characterization of a Magnetorheological Fluid Subjected to Long-Term Operation in Damper

Utami D, Ubaidillah, Mazlan SA, Imaduddin F, Nordin NA, Bahiuddin I, et al.

Materials (Basel), 2018 Nov 06;11(11).
PMID: 30404193 DOI: 10.3390/ma11112195

This paper investigates the field-dependent rheological properties of magnetorheological (MR) fluid used to fill in MR dampers after long-term cyclic operation. For testing purposes, a meandering MR valve was customized to create a double-ended MR damper in which MR fluid flowed inside the valve due to the magnetic flux density. The test was conducted for 170,000 cycles using a fatigue dynamic testing machine which has 20 mm of stroke length and 0.4 Hz of frequency. Firstly, the damping force was investigated as the number of operating cycles increased. Secondly, the change in viscosity of the MR fluid was identified as in-use thickening (IUT). Finally, the morphological observation of MR particles was undertaken before and after the long-term operation. From these tests, it was demonstrated that the damping force increased as the number of operating cycles increases, both when the damper is turn on (on-state) and off (off-state). It is also observed that the particle size and shape changed due to the long operation, showing irregular particles.
Major health impact of accelerated aging in young HIV-infected individuals on antiretroviral therapy

Rajasuriar R, Chong ML, Ahmad Bashah NS, Abdul Aziz SA, Mcstea M, Lee ECY, et al.

AIDS, 2017 06 19;31(10):1393-1403.
PMID: 28358731 DOI: 10.1097/QAD.0000000000001475

BACKGROUND: Aging among HIV-infected individuals on antiretroviral therapy (ART) is a significant clinical challenge; however, studies assessing multidimensional aspects of aging are lacking. We characterized 10 geriatric conditions encompassing multiple functional domains, its health impact and associated risk factors in HIV-infected and age-matched uninfected controls.

METHODS: HIV-infected individuals were recruited from the outpatient clinic in University Malaya Medical Centre, Malaysia and controls from the community. All participants were aged at least 25 years of age with no acute illness, and HIV-infected individuals were on stable ART. Geriatric conditions were assessed and the burden scored as a composite of geriatric conditions present in an individual (total score = 10). Multivariate regression analysis was performed to determine the risk factors and health impact associated with the burden of geriatric conditions.

RESULTS: We analyzed data from 336 HIV-infected individuals (total HIV+), of whom 172 were matched for age, sex, and ethnicity with 172 HIV-uninfected controls (matched subset). In the total HIV-positive cohort, median (interquartile range) age was 44 (38-51) years and CD4 T-cell count was 562 (398-737) cells/μl. The burden of geriatric conditions was significantly higher in the HIV-infected group compared with controls (P
Fulltext Information needs on type 1 diabetes mellitus (T1DM) and its management in children and adolescents: a qualitative study

Muhammed Elamin S, Muhamad Arshad NF, Md Redzuan A, Abdul Aziz SA, Hong J, Chua XY, et al.

BMJ Open, 2024 Apr 02;14(4):e079606.
PMID: 38569693 DOI: 10.1136/bmjopen-2023-079606

OBJECTIVE: The objective of this study is to explore the information needs related to insulin therapy in children and adolescents with type 1 diabetes mellitus (T1DM) from the children's perspectives as well as their caregivers.
DESIGN: Qualitative study; semistructured interviews. To identify emerging themes relating to information needs, open coding and thematic analysis were employed.
SETTING: Participants were recruited from a tertiary care children's hospital in Kuala Lumpur, Malaysia and a specialist hospital in Riyadh, Saudi Arabia.
PARTICIPANTS: Thirty one children with a mean age of 11.5 years (SD=1.9) and their caregivers were interviewed. Seventeen participants were from Malaysia and 14 were from Saudi Arabia.
RESULTS: Four themes of information emerged from the interviews, including information related to (1) hypoglycaemia and hyperglycaemia, (2) insulin therapy, (3) injection technique and (4) other information needs pertaining to continuous glucose monitoring, access to peer groups and future advances in insulin therapy.
CONCLUSION: This study provided valuable insights into the information needs related to T1DM and insulin therapy among children and adolescents with T1DM that should be considered by stakeholders in the development of age-appropriate education materials. Such materials will assist children and adolescents to better manage their life-long T1DM condition from adolescence until adulthood.
Information Received and Usefulness of the Sources of Information to Cancer Patients at a Tertiary Care Centre in Malaysia

Lew YL, Ismail F, Abdul Aziz SA, Mohamed Shah N

J Cancer Educ, 2021 04;36(2):350-358.
PMID: 31659620 DOI: 10.1007/s13187-019-01637-9

Most people with cancer have a combination of treatments, such as surgery with chemotherapy and/or radiation therapy. Providing good quality cancer-related information enables patients to be better prepared for treatment and improves their adherence. This study aimed to determine the level of information received and the perceived usefulness of the sources of information to cancer patients. A 4-month study was conducted at a day care oncology unit and oncology ward of a tertiary care centre in Malaysia using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Information Module (EORTC QLQ-INFO 25). In total, 103 patients successfully completed the questionnaire. Level of information received was moderate. Patients were well-informed about medical tests (mean ± SD = 74.2 ± 17.8) followed by the disease itself (mean ± SD = 68.0 ± 13.6). Patients received less information on both other services (mean ± SD = 47.6 ± 18.1) and different places of care (mean ± SD = 41.3 ± 22.3). Although the correlation between age and level of information received was poor (r = - 0.201; P = .042), younger patients (≤ 65 years old) were found to have higher level of information received than older patients (mean ± SD = 61.5 ± 11.2 versus 57.8 ± 6.6; P = .046). Doctors (mean ± SD = 88.1 ± 17.1), nurses (mean ± SD = 83.7 ± 20.3), and family members (mean ± SD = 81.1 ± 24.9) were the most useful sources of information by cancer patients. There is still a need for improvement in the provision of information by the healthcare team and prioritisation should depend on patients' individual characteristics and their needs of information. More attention is needed in delivering required information especially to older patients.
Exposure to potentially harmful excipients in medications among neonates at a state hospital in Malaysia

Wong SW, Chew SP, Abdul Aziz SA, Mohamed Shah N

Drug Dev Ind Pharm, 2024 Mar 22.
PMID: 38459761 DOI: 10.1080/03639045.2024.2327462

OBJECTIVES: This study aimed to determine the incidence, types and predictors of Potentially Harmful Excipients (PHE) exposure among hospitalized neonates.
METHODS: A prospective observational study was conducted from March to April 2022 in neonatal wards at a state hospital in Malaysia. The PHEs of interest were aspartame, benzalkonium chloride, benzyl alcohol, benzoic acid or benzoates, ethanol, parabens, polysorbate 80, propylene glycol, saccharin sodium, sorbitol and sulfites. Product information leaflets (PILs) and summaries of product characteristics (SPCs) were referred to obtain information on active pharmaceutical ingredient, strength, trade name as well as type and amount of the excipients.
RESULTS: A total of 108 neonates were recruited and 97.2% of them were exposed to at least one PHE. Parabens (47.2%) and sulfites (27.5%) were the two most commonly administered PHEs. Benzyl alcohol is contraindicated in neonates but was administered to 8% of neonates in this study. The median daily dose of ethanol (24.11 mg/kg/day, IQR 19.73, 28.49) exceeded the acceptable daily intake (ADI) by four times. However, the dose was not available for all PHEs as this information is not always available in the PIL or SPC. Administration of cardiovascular drugs was associated with a higher risk of exposure to any PHE (OR 6.38, CI 2.75, 14.79, p-value < 0.001).
CONCLUSION: The exposure of PHE among neonates in this study is high with certain PHEs exceeding the ADI. It highlights the need for certain strategies to be implemented to reduce such exposure in neonates.
Evaluation of mean glandular dose and modulation transfer function for different tube potentials and target-filter combinations in computed radiography mammography

Abdul Aziz SA, Mohd Saparudin AK, Harun AZ

Malays J Med Sci, 2013 May;20(3):23-30.
PMID: 23966821 MyJurnal

BACKGROUND: Different target-filter combinations in computed radiography have different impacts on the dose and image quality in digital radiography. This study aims to evaluate the mean glandular dose (MGD) and modulation transfer function (MTF) of various target-filter combinations by investigating the signal intensities of X-ray beams.
METHODS: General Electric (GE) Senographe DMR Plus mammography unit was used for MGD and MTF evaluation. The measured MGD was compared with the dose reference level (DRL), whereas the MTF was evaluated using ImageJ 1.46o software. A modified Mammography Accreditation Phantom RMI 156 was exposed using different target-filter combinations of molybdenum-molybdenum (Mo-Mo), molybdenum-rhodium (Mo-Rh) and rhodium-rhodium (Rh-Rh) at two different tube voltages, 26 kV and 32 kV with 50 mAs.
RESULTS: In the MGD evaluations, all target-filters gave an MGD value of < 1.5 mGy. The one-way ANOVA test showed a highly significant interaction between the MGD and the kilovoltage and target-filter material used (26 kV: F (2,12) = 49,234, P = 0.001;32 kV: F (2,12) = 89,972, P = 0.001). A Tukey post-hoc test revealed that the MGD for 26 kV and 32 kV was highly affected by the target-filter combinations. The test of homogeneity of variances indicates that the MGD varies significantly for 26 kV and 32 kV images (0.045 and 0.030 (P < 0.05), respectively). However, the one-way ANOVA for the MTF shows that no significant difference exists between the target-filter combinations used with 26 kV and 32 kV images either in parallel or perpendicular to the chest wall side F (2,189) = 0.26, P > 0.05).
CONCLUSION: Higher tube voltage and atomic number target-filter yield higher MGD values. However, the MTF is independent of the X-ray energy and the type of target-filter combinations used.
Fulltext Enhancement of Viscoelastic and Electrical Properties of Magnetorheological Elastomers with Nanosized Ni-Mg Cobalt-Ferrites as Fillers

Abdul Aziz SA, Mazlan SA, Ubaidillah U, Shabdin MK, Yunus NA, Nordin NA, et al.

Materials (Basel), 2019 Oct 28;12(21).
PMID: 31661837 DOI: 10.3390/ma12213531

Carbon-based particles, such as graphite and graphene, have been widely used as a filler in magnetorheological elastomer (MRE) fabrication in order to obtain electrical properties of the material. However, these kinds of fillers normally require a very high concentration of particles to enhance the conductivity property. Therefore, in this study, the nanosized Ni-Mg cobalt ferrite is introduced as a filler to soften MRE and, at the same time, improve magnetic, rheological, and conductivity properties. Three types of MRE samples without and with different compositions of Mg, namely Co0.5Ni0.2Mg0.3Fe2O4 (A1) and Co0.5Ni0.1Mg0.4Fe2O4 (A2), are fabricated. The characterization related to the micrograph, magnetic, and rheological properties of the MRE samples are analyzed using scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and the rheometer. Meanwhile, the effect of the nanosized Ni-Mg cobalt ferrites on the electrical resistance property is investigated and compared with the different Mg compositions. It is shown that the storage modulus of the MRE sample with the nanosized Ni-Mg cobalt ferrites is 43% higher than that of the MRE sample without the nanomaterials. In addition, it is demonstrated that MREs with the nanosized Ni-Mg cobalt ferrites exhibit relatively low electrical resistance at the on-state as compared to the off-state condition, because MRE with a higher Mg composition shows lower electrical resistance when higher current flow occurs through the materials. This salient property of the proposed MRE can be effectively and potentially used as an actuator to control the viscoelastic property of the magnetic field or sensors to measure the strain of the flexible structures by the electrical resistance signal.
Fulltext Effects of Petroleum-Based Oils as Dispersing Aids on Physicochemical Characteristics of Magnetorheological Elastomers

Muhammad Zaki N, Yunus NA, Yusoff MS, Mazlan SA, Abdul Aziz SA, Izni NA, et al.

Materials (Basel), 2021 Nov 19;14(22).
PMID: 34832425 DOI: 10.3390/ma14227026

This paper investigated the effects of petroleum-based oils (PBOs) as a dispersing aid on the physicochemical characteristics of natural rubber (NR)-based magnetorheological elastomers (MREs). The addition of PBOs was expected to overcome the low performance of magnetorheological (MR) elastomers due to their inhomogeneous dispersion and the mobility of magnetic particles within the elastomer matrix. The NR-based MREs were firstly fabricated by mixing the NR compounds homogeneously with different ratios of naphthenic oil (NO), light mineral oil (LMO), and paraffin oil (PO) to aromatic oil (AO), with weight percentage ratios of 100:0, 70:30, 50:50, and 30:70, respectively. From the obtained results, the ratios of NO mixed with low amounts of AO improved the material physicochemical characteristics, such as thermal properties. Meanwhile, LMO mixed the AO led to the best results for curing characteristics, microstructure observation, and magnetic properties of the MREs. We found that the LMO mixed with a high content of AO could provide good compatibility between the rubber molecular and magnetic particles due to similar chemical structures, which apparently enhance the physicochemical characteristics of MREs. In conclusion, the 30:70 ratio of LMO:AO is considered the preferable dispersing aid for MREs due to structural compounds present in the oil that enhance the physicochemical characteristics of the NR-based MREs.
Fulltext Effectiveness of antihypertensive drugs in hypertensive patients with end stage renal failure

Kumolosasi E, Ng WB, Abdul Aziz SA

Med J Malaysia, 2012 Aug;67(4):379-85.
PMID: 23082445 MyJurnal

Hypertension has been identified as one of the causes for end stage renal failure (ESRF) and is likely to worsen kidney function. This retrospective study was carried out at a tertiary hospital in Malaysia with the objective of determining the effectiveness of combination antihypertensive drugs in hypertensive patients with ESRF admitted between 2006 and 2008. Patients with incomplete data and who were on monotherapy were excluded from this study. Although six different combinations gave significant reductions in systolic blood pressure (SBP) (13.38 +/- 9.11 mmHg, p < 0.05) and diastolic blood pressure (DBP) (6.03 +/- 11.39 mmHg, p < 0.05), 69.16% patients did not achieve target blood pressure (BP) (< or = 130/80 mmHg). Combination of beta blocker (BB) with calcium channel blocker (CCB) was the most commonly used. The CCB-diuretic regimen achieved highest percentage of BP control compared to others (40%). Comparison of blood pressure reduction between different combinations of antihypertensive drugs were not significant (p > 0.05) except for CCB-diuretics and BB-CCB-alpha blocker. The findings suggested better BP control with CCB-diuretic relative to other combinations used.
Fulltext Dual Properties of Polyvinyl Alcohol-Based Magnetorheological Plastomer with Different Ratio of DMSO/Water

Hapipi NM, Mazlan SA, Ubaidillah U, Abdul Aziz SA, Choi SB, Nordin NA, et al.

Sensors (Basel), 2021 Nov 22;21(22).
PMID: 34833835 DOI: 10.3390/s21227758

Polyvinyl alcohol (PVA)-based magnetorheological plastomer (MRP) possesses excellent magnetically dependent mechanical properties such as the magnetorheological effect (MR effect) when exposed to an external magnetic field. PVA-based MRP also shows a shear stiffening (ST) effect, which is very beneficial in fabricating pressure sensor. Thus, it can automatically respond to external stimuli such as shear force without the magnetic field. The dual properties of PVA-based MRP mainly on the ST and MR effect are rarely reported. Therefore, this work empirically investigates the dual properties of this smart material under the influence of different solvent compositions (20:80, 40:60, 60:40, and 80:20) by varying the ratios of binary solvent mixture (dimethyl sulfoxide (DMSO) to water). Upon applying a shear stress with excitation frequencies from 0.01 to 10 Hz, the storage modulus (G') for PVA-based MRP with DMSO to water ratio of 20:40 increases from 6.62 × 10-5 to 0.035 MPa. This result demonstrates an excellent ST effect with the relative shear stiffening effect (RSTE) up to 52,827%. In addition, both the ST and MR effect show a downward trend with increasing DMSO content to water. Notably, the physical state of hydrogel MRP could be changed with different solvent ratios either in the liquid-like or solid-like state. On the other hand, a transient stepwise experiment showed that the solvent's composition had a positive effect on the arrangement of CIPs within the matrix as a function of the external magnetic field. Therefore, the solvent ratio (DMSO/water) can influence both ST and MR effects of hydrogel MRP, which need to be emphasized in the fabrication of hydrogel MRP for appropriate applications primarily with soft sensors and actuators for dynamic motion control.

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