Displaying publications 1 - 20 of 61 in total

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  1. Abd Majid N, Rainis R, Sahani M, Mohamed AF, Abdul Ghani Aziz SA, Muhamad Nazi N
    Geospat Health, 2021 03 11;16(1).
    PMID: 33706498 DOI: 10.4081/gh.2021.915
    In recent decades, dengue outbreaks have become increasingly common around the developing countries, including Malaysia. Thus, it is essential for rural as well as urbanised livelihood to understand the distribution pattern of this infection. The objective of this study is to determine the trend of dengue cases reported from the year 2014 to 2018 and the spatial pattern for this spread. Spatial statistical analyses conducted found that the distribution pattern and spatial mean centre for dengue cases were clustered in the eastern part of the Bangi region. Directional distribution observed that the elongated polygon of dengue cluster stretched from the Northeast to the Southwest of Bangi District. The standard distance observed for dengue cases was smallest in the year 2014 (0.017 m), and largest in 2016 (0.019 m), whereas in the year 2015, 2017 and 2018, it measured 0.018 m. The average nearest neighbour analysis also displayed clustered patterns for dengue cases in the Bangi District. The three spatial statistical analyses (spatial mean centre, standard distance and directional distribution) findings illustrate that the dengue cases from the year 2014 to 2018 are clustered in the Northeast to the Southwest of the study region.
  2. 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.
  3. Abdul Aziz SA, Mcstea M, Ahmad Bashah NS, Chong ML, Ponnampalavanar S, Syed Omar SF, et al.
    AIDS, 2018 05 15;32(8):1025-1034.
    PMID: 29547442 DOI: 10.1097/QAD.0000000000001798
    OBJECTIVES: In a clinic-based, treated HIV-infected cohort, we identified individuals with sarcopenia and compared with age, sex and ethnically matched controls; and investigated associated risk factors and health outcomes.

    DESIGN: Sarcopenia (age-related muscle loss) causes significant morbidity to the elderly, leading to frequent hospitalizations, disability and death. Few have characterized sarcopenia in the HIV-infected who experience accelerated aging.

    METHODS: Sarcopenia was defined as low muscle mass with weak grip strength and/or slow gait speed using lower 20th percentiles of controls. Multivariate logistic and linear regression analyses were used to explore risk factors and health-related outcomes associated with sarcopenia among HIV-infected individuals.

    RESULTS: We recruited 315 HIV-infected individuals aged at least 25 years with at least 1-year history of undetectable viral load on treatment (HIV RNA <50 copies/ml). Percentage of sarcopenia in 315 HIV-infected was 8%. Subsequently, 153 of the 315 were paired with age, sex and ethnically matched HIV-uninfected. The percentage of sarcopenia in the HIV-infected (n = 153) compared with uninfected (n = 153) were 10 vs. 6% (P = 0.193) respectively, whereas of those at least 50 years of age among them were 17% vs. 4% (P = 0.049), respectively. Associated risk factors among the HIV-infected include education level, employment status, BMI, baseline CD4 cell count, duration on NRTIs and GGT levels. Identified negative outcomes include mortality risk scores [5.42; 95% CI 1.46-9.37; P = 0.007) and functional disability (3.95; 95% CI 1.57-9.97; P = 0.004).

    CONCLUSION: Sarcopenia is more prevalent in HIV-infected at least 50 years old compared with matched controls. Our findings highlight associations between sarcopenia with loss of independence and greater healthcare burden among treated HIV-infected individuals necessitating early recognition and intervention.

  4. 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.

  5. Abiddin NZ, Ibrahim I, Abdul Aziz SA
    Front Psychol, 2022;13:819860.
    PMID: 35664130 DOI: 10.3389/fpsyg.2022.819860
    The purpose of this paper is to determine the performance of employees employed at home during the COVID-19 pandemic in Malaysia and Indonesia, also to examine the employee's quality of life affected by COVID-19. The current study is aimed to critically determine the performance of employees employed at home during the COVID-19 pandemic. The author has analyzed and reviewed various sources of articles, reports, and documents from previous research and literature. The findings explain that working from home has provided advantages and disadvantages for both the employees and the organization and is responsible for the decrease in employee productivity. In addition, the findings conclude that the fact that working from home is generally not feasible because many areas of work cannot be done from home, although for many employees, working from home has provided a work-life balance.
  6. Ahmad AF, Aziz SA, Abbas Z, Obaiys SJ, Matori KA, Zaid MHM, et al.
    Polymers (Basel), 2019 Apr 11;11(4).
    PMID: 30978935 DOI: 10.3390/polym11040661
    In this study, a nanocomposite of reduced graphene oxide (RGO) nanofiller-reinforcement poly(lactic acid) (PLA)/poly(ethylene glycol) (PEG) matrix was prepared via the melt blending method. The flexibility of PLA was improved by blending the polymer with a PEG plasticizer as a second polymer. To enhance the electromagnetic interference shielding properties of the nanocomposite, different RGO wt % were combined with the PLA/PEG blend. Using Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and X-ray diffraction, the structural, microstructure, and morphological properties of the polymer and the RGO/PLA/PEG nanocomposites were examined. These studies showed that the RGO addition did not considerably affect the crystallinity of the resulting nanomaterials. Thermal analysis (TGA) reveals that the addition of RGO highly improved the thermal stability of PLA/PEG nanocomposites. The dielectric properties and electromagnetic interference shielding effectiveness of the synthesized nanocomposites were calculated and showed a higher SE total value than the target value (20 dB). On the other hand, the results showed an increased power loss by increasing the frequency and conversely decreased with an increased percentage of filler.
  7. 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.
  8. Ahmed H, Paterson I, Aziz SA, Cremona O, Robinson M, Carrozzo M, et al.
    J Oral Pathol Med, 2023 Sep;52(8):710-717.
    PMID: 37339783 DOI: 10.1111/jop.13460
    BACKGROUND: Most oral squamous cell carcinoma patients present with late-stage disease. Early detection of the disease is considered to be the most effective way of improving patient outcomes. Several biomarkers have been identified as indicators of oral cancer development and progression; however, none have been translated into clinical practice. In this study, we have investigated the role of Epsin3, an endocytic adaptor protein, and Notch1, a transmembrane signalling protein, in oral carcinogenesis with a view to explore their potential as biomarkers.

    METHODS: Oral cancer cell lines and a normal oral keratinocyte cell line were used together with tissue samples of normal oral mucosa (n = 21), oral epithelial dysplasia (n = 74) and early stage (Stages I and II) oral squamous cell carcinoma (n = 31). Immunocytochemical staining, immunoblotting and real-time quantitative polymerase chain reaction (PCR) were performed to assess protein as well as gene expression levels.

    RESULTS: The expression levels of Epsin3 and Notch1 mRNA and protein are variable across different oral squamous cell carcinoma derived cell lines. Epsin3 was upregulated in oral epithelial dysplasia and oral squamous cell carcinoma tissues compared with normal epithelium. Overexpression of Epsin3 resulted in a significant reduction of Notch1 expression in oral squamous cell carcinoma. Notch1 was generally downregulated in the dysplasia and oral squamous cell carcinoma samples.

    CONCLUSION: Epsin3 is upregulated in oral epithelial dysplasia and oral squamous cell carcinoma and has the potential to be used as a biomarker for oral epithelial dysplasia. Notch signalling is downregulated in oral squamous cell carcinoma, possibly through an Epsin3-induced de-activation pathway.

  9. Ali N, Aziz SA, Nordin S, Mi NC, Abdullah N, Paranthaman V, et al.
    Subst Use Misuse, 2018 01 28;53(2):239-248.
    PMID: 29116878 DOI: 10.1080/10826084.2017.1385630
    BACKGROUND: Opioid misuse and dependence is a global issue with a huge negative impact. In Malaysia, heroin is still the main illicit drug used, and methadone maintenance treatment (MMT) has been used since 2005.
    OBJECTIVE: To evaluate the effectiveness of MMT.
    METHODS: This was a cross-sectional study conducted in 103 treatment centers between October and December 2014 using a set of standard questionnaires. Data were analyzed using SPSS Statistics 20.
    RESULTS: There were 3254 respondents (93.6% response rate); of these 17.5% (n = 570) transferred to another treatment center, 8.6% (n = 280) died, 29.2% (n = 950) defaulted, and 7.6% (n = 247) were terminated for various reasons. Hence, 1233 (37%) respondents' baseline and follow-up data were further analyzed. Respondents had a mean age of 39.2 years old and were mainly male, Malay, Muslim, married (51.1%, n = 617), and currently employed. Few showed viral seroconversion after they started MMT (HIV: 0.5%, n = 6; Hepatitis B: 0.3%, n = 4; Hepatitis C: 2.7%, n = 29). There were significant reductions in opioid use, HIV risk-taking score (p < 0.01), social functioning (p < 0.01), crime (p < 0.01), and health (p < 0.01). However, there were significant improvements in quality of life in the physical, psychological, social, and environmental domains. Factors associated with change were being married, employed, consuming alcohol, and high criminality at baseline. Lower methadone dosage was significantly associated with improvements in the physical, psychological, and environmental domains.
    Conclusion/Importance: The MMT program was found to be successful; hence, it should be expanded.
  10. Aziz SA, Nuawi MZ, Nor MJ
    J Occup Health, 2015;57(6):513-20.
    PMID: 26269278 DOI: 10.1539/joh.14-0206-OA
    OBJECTIVE: The objective of this study was to present a new method for determination of hand-arm vibration (HAV) in Malaysian Army (MA) three-tonne truck steering wheels based on changes in vehicle speed using regression model and the statistical analysis method known as Integrated Kurtosis-Based Algorithm for Z-Notch Filter Technique Vibro (I-kaz Vibro).

    METHODOLOGY: The test was conducted for two different road conditions, tarmac and dirt roads. HAV exposure was measured using a Brüel & Kjær Type 3649 vibration analyzer, which is capable of recording HAV exposures from steering wheels. The data was analyzed using I-kaz Vibro to determine the HAV values in relation to varying speeds of a truck and to determine the degree of data scattering for HAV data signals.

    RESULTS: Based on the results obtained, HAV experienced by drivers can be determined using the daily vibration exposure A(8), I-kaz Vibro coefficient (Ƶ(v)(∞)), and the I-kaz Vibro display. The I-kaz Vibro displays also showed greater scatterings, indicating that the values of Ƶ(v)(∞) and A(8) were increasing. Prediction of HAV exposure was done using the developed regression model and graphical representations of Ƶ(v)(∞). The results of the regression model showed that Ƶ(v)(∞) increased when the vehicle speed and HAV exposure increased.

    DISCUSSION: For model validation, predicted and measured noise exposures were compared, and high coefficient of correlation (R(2)) values were obtained, indicating that good agreement was obtained between them. By using the developed regression model, we can easily predict HAV exposure from steering wheels for HAV exposure monitoring.

  11. Aziz SA, Clements GR, Peng LY, Campos-Arceiz A, McConkey KR, Forget PM, et al.
    PeerJ, 2017;5:e3176.
    PMID: 28413729 DOI: 10.7717/peerj.3176
    There is an urgent need to identify and understand the ecosystem services of pollination and seed dispersal provided by threatened mammals such as flying foxes. The first step towards this is to obtain comprehensive data on their diet. However, the volant and nocturnal nature of bats presents a particularly challenging situation, and conventional microhistological approaches to studying their diet can be laborious and time-consuming, and provide incomplete information. We used Illumina Next-Generation Sequencing (NGS) as a novel, non-invasive method for analysing the diet of the island flying fox (Pteropus hypomelanus) on Tioman Island, Peninsular Malaysia. Through DNA metabarcoding of plants in flying fox droppings, using primers targeting the rbcL gene, we identified at least 29 Operationally Taxonomic Units (OTUs) comprising the diet of this giant pteropodid. OTU sequences matched at least four genera and 14 plant families from online reference databases based on a conservative Least Common Ancestor approach, and eight species from our site-specific plant reference collection. NGS was just as successful as conventional microhistological analysis in detecting plant taxa from droppings, but also uncovered six additional plant taxa. The island flying fox's diet appeared to be dominated by figs (Ficus sp.), which was the most abundant plant taxon detected in the droppings every single month. Our study has shown that NGS can add value to the conventional microhistological approach in identifying food plant species from flying fox droppings. At this point in time, more accurate genus- and species-level identification of OTUs not only requires support from databases with more representative sequences of relevant plant DNA, but probably necessitates in situ collection of plant specimens to create a reference collection. Although this method cannot be used to quantify true abundance or proportion of plant species, nor plant parts consumed, it ultimately provides a very important first step towards identifying plant taxa and spatio-temporal patterns in flying fox diets.
  12. Aziz SA, Clements GR, McConkey KR, Sritongchuay T, Pathil S, Abu Yazid MNH, et al.
    Ecol Evol, 2017 Nov;7(21):8670-8684.
    PMID: 29152168 DOI: 10.1002/ece3.3213
    Fruit bats provide valuable pollination services to humans through a unique coevolutionary relationship with chiropterophilous plants. However, chiropterophily in the Old World and the pollination roles of large bats, such as flying foxes (Pteropus spp., Acerodon spp., Desmalopex spp.), are still poorly understood and require further elucidation. Efforts to protect these bats have been hampered by a lack of basic quantitative information on their role as ecosystem service providers. Here, we investigate the role of the locally endangered island flying fox Pteropus hypomelanus in the pollination ecology of durian (Durio zibethinus), an economically important crop in Southeast Asia. On Tioman Island, Peninsular Malaysia, we deployed 19 stations of paired infrared camera and video traps across varying heights at four individual flowering trees in a durian orchard. We detected at least nine species of animal visitors, but only bats had mutualistic interactions with durian flowers. There was a clear vertical stratification in the feeding niches of flying foxes and nectar bats, with flying foxes feeding at greater heights in the trees. Flying foxes had a positive effect on mature fruit set and therefore serve as important pollinators for durian trees. As such, semi-wild durian trees-particularly tall ones-may be dependent on flying foxes for enhancing reproductive success. Our study is the first to quantify the role of flying foxes in durian pollination, demonstrating that these giant fruit bats may have far more important ecological, evolutionary, and economic roles than previously thought. This has important implications and can aid efforts to promote flying fox conservation, especially in Southeast Asian countries.
  13. Aziz SA, Clements GR, Giam X, Forget PM, Campos-Arceiz A
    Hum Ecol Interdiscip J, 2017;45(3):377-389.
    PMID: 28680192 DOI: 10.1007/s10745-017-9905-6
    As tropical landscapes become increasingly human-dominated, conflicts between people and wildlife threaten ecological processes. Old World fruit bats such as flying foxes are especially susceptible to extinction risk because there is low interest in their conservation, particularly when they are considered pests. In order to arrest fruit bat declines, there is an urgent need to understand human-bat conflict and its implications. On a tropical island in Peninsular Malaysia, we conducted a questionnaire survey to investigate coexistence between people and the island flying fox (Pteropus hypomelanus). Among 119 respondents, knowledge of ecosystem services provided by flying foxes was extremely low. Most respondents held negative attitudes towards the bats, and older male locals were more likely to support killing them. This was also true for older owners of fruit trees who derived income from selling fruit, and experienced flying fox raids. Our results can be used to design appropriate interventions to support conservation efforts, and has important implications for managing conflicts between humans and synanthropic wildlife.
  14. Aziz SA, See TL, Khuay LY, Osman K, Abu Bakar MA
    Malays J Med Sci, 2005 Jul;12(2):22-6.
    PMID: 22605954
    The study was carried out to determine the in vitro effect of Plantago major extract on calcium oxalate crystals and to compare the effects of Plantago major extract with clinically used drugs like allopurinol and potassium citrate (positive controls). Modified Schneider slide gel method was used for the in vitro study and the crystals formed were measured by Image Analyser system KS 300, 3.0 Carl Zeiss. The concentrations of Plantago major extract used were from 100ppm to 350ppm. Plantago major extract at concentrations in the range of (100ppm-350ppm) significantly inhibited the size of calcium oxate crystals (dihydrate variety) against negative control (p<0.05) and against positive controls (p<0.05). However the inhibition concentration 50 (IC(50)) values on the size of calcium oxalate crystal for the extract, potassium citrate and allopurinol were 300ppm, 350ppm and 450ppm respectively. Extract of Plantago major also has inhibition effect on the number of crystals but it was not significant. In conclusion extract of Plantago major was better than allopurinol and potassium citrate in inhibiting the size of the calcium oxalate crystal in-vitro.
  15. Clements GR, Rayan DM, Aziz SA, Kawanishi K, Traeholt C, Magintan D, et al.
    Integr Zool, 2012 Dec;7(4):400-406.
    PMID: 23253371 DOI: 10.1111/j.1749-4877.2012.00314.x
    In 2008, the IUCN threat status of the Asian tapir (Tapirus indicus) was reclassified from 'vulnerable' to 'endangered'. The latest distribution map from the IUCN Red List suggests that the tapirs' native range is becoming increasingly fragmented in Peninsular Malaysia, but distribution data collected by local researchers suggest a more extensive geographical range. Here, we compile a database of 1261 tapir occurrence records within Peninsular Malaysia, and demonstrate that this species, indeed, has a much broader geographical range than the IUCN range map suggests. However, extreme spatial and temporal bias in these records limits their utility for conservation planning. Therefore, we used maximum entropy (MaxEnt) modeling to elucidate the potential extent of the Asian tapir's occurrence in Peninsular Malaysia while accounting for bias in existing distribution data. Our MaxEnt model predicted that the Asian tapir has a wider geographic range than our fine-scale data and the IUCN range map both suggest. Approximately 37% of Peninsular Malaysia contains potentially suitable tapir habitats. Our results justify a revision to the Asian tapir's extent of occurrence in the IUCN Red List. Furthermore, our modeling demonstrated that selectively logged forests encompass 45% of potentially suitable tapir habitats, underscoring the importance of these habitats for the conservation of this species in Peninsular Malaysia.
  16. Getachew Y, Hassan L, Zakaria Z, Zaid CZ, Yardi A, Shukor RA, et al.
    J Appl Microbiol, 2012 Nov;113(5):1184-95.
    PMID: 22906187 DOI: 10.1111/j.1365-2672.2012.05406.x
    This study determined the risk factors and characteristics of vancomycin-resistant Enterococci (VRE) among individuals working with animals in Malaysia.
  17. 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.
  18. 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.
  19. Jeon HJ, Ju PC, Sulaiman AH, Aziz SA, Paik JW, Tan W, et al.
    Clin Psychopharmacol Neurosci, 2022 Feb 28;20(1):70-86.
    PMID: 35078950 DOI: 10.9758/cpn.2022.20.1.70
    Objective: To evaluate the long-term safety and efficacy of intranasal esketamine in patients with treatment-resistant depression from the Asian subgroup of the SUSTAIN-2 study.

    Methods: SUSTAIN-2 was a phase 3, open-label, single-arm, multicenter study comprising a 4-week screening, 4-week induction, 48-week optimization/maintenance, and 4-week follow-up (upon esketamine discontinuation) phase. Patients with treatment-resistant depression received esketamine plus an oral antidepressant during the treatment period.

    Results: The incidence of ≥ 1 serious treatment-emergent adverse event (TEAE) among the 78 subjects from the Asian subgroup (Taiwan: 33, Korea: 26, Malaysia: 19) was 11.5% (n = 9); with no fatal TEAE. 13 Asian patients (16.7%) discontinued esketamine due to TEAEs. The most common TEAEs were dizziness (37.2%), nausea (29.5%), dissociation (28.2%), and headache (21.8%). Most TEAEs were mild to moderate in severity, transient and resolved on the same day. Upon discontinuation of esketamine, no trend in withdrawal symptoms was observed to associate long-term use of esketamine with withdrawal syndrome. There were no reports of drug seeking, abuse, or overdose. Improvements in symptoms, functioning and quality of life, occurred during in the induction phase and were generally maintained through the optimization/maintenance phases of the study.

    Conclusion: The safety and efficacy of esketamine in the Asian subgroup was generally consistent with the total SUSTAIN-2 population. There was no new safety signal and no indication of a high potential for abuse with the long-term (up to one year) use of esketamine in the Asian subgroup. Most of the benefits of esketamine occurred early during the induction phase.

  20. Johari MAF, Sarman AM, Mazlan SA, U U, Nordin NA, Abdul Aziz SA, et al.
    Materials (Basel), 2021 Aug 05;14(16).
    PMID: 34442907 DOI: 10.3390/ma14164384
    Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.
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