Displaying publications 281 - 300 of 409 in total

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  1. Fulltext Enhancement of Particle Alignment Using Silicone Oil Plasticizer and Its Effects on the Field-Dependent Properties of Magnetorheological Elastomers
    Khairi MHA, Fatah AYA, Mazlan SA, Ubaidillah U, Nordin NA, Ismail NIN, et al.
    Int J Mol Sci, 2019 Aug 21;20(17).
    PMID: 31438576 DOI: 10.3390/ijms20174085
    The existing mold concept of fabricating magnetorheological elastomer (MRE) tends to encounter several flux issues due to magnetic flux losses inside the chamber. Therefore, this paper presents a new approach for enhancing particle alignment through MRE fabrication as a means to provide better rheological properties. A closed-loop mold, which is essentially a fully guided magnetic field inside the chamber, was designed in order to strengthen the magnetic flux during the curing process with the help of silicone oil (SO) plasticizers. The oil serves the purpose of softening the matrix. Scanning electron microscopy (SEM) was used to observe the surface morphology of the fabricated MRE samples. The field-dependent dynamic properties of the MREs were measured several ways using a rheometer, namely, strain sweep, frequency sweep, and magnetic field sweep. The analysis implied that the effectiveness of the MRE was associated with the use of the SO, and the closed-loop mold helped enhance the absolute modulus up to 0.8 MPa. The relative magnetorheological (MR) effects exhibited high values up to 646%. The high modulus properties offered by the MRE with SO are believed to be potentially useful in industry applications, particularly as vibration absorbers, which require a high range of stiffness.
  2. Rehabilitation in Malaysia
    Naicker AS, Mohamad Yatim S, Engkasan JP, Mazlan M, Yusof YM, Yuliawiratman BS, et al.
    Phys Med Rehabil Clin N Am, 2019 11;30(4):807-816.
    PMID: 31563172 DOI: 10.1016/j.pmr.2019.07.006
    This article reviews the epidemiology, rehabilitation intervention strategies, and rehabilitation resources for persons with disabilities (PWD) in Malaysia. Currently, the registered number of PWD is 409,269 individuals, 1.3% of the total population, which is far less than the World Health Organization estimation of 10%. The rehabilitation implementation strategies include health policies, health promotion, and prevention programs. Health-related services for PWD are provided by many government agencies, including health, welfare, education, manpower, housing, and the private sector and nongovernment organizations. It is hoped national health programs can ensure special care and rehabilitation for PWD, optimizing self-reliance and social integration.
  3. Mycobacterium tuberculosis complex in wildlife: Review of current applications of antemortem and postmortem diagnosis
    Lekko YM, Ooi PT, Omar S, Mazlan M, Ramanoon SZ, Jasni S, et al.
    Vet World, 2020 Sep;13(9):1822-1836.
    PMID: 33132593 DOI: 10.14202/vetworld.2020.1822-1836
    Tuberculosis (TB) is a chronic inflammatory and zoonotic disease caused by Mycobacterium tuberculosis complex (MTBC) members, which affects various domestic animals, wildlife, and humans. Some wild animals serve as reservoir hosts in the transmission and epidemiology of the disease. Therefore, the monitoring and surveillance of both wild and domestic hosts are critical for prevention and control strategies. For TB diagnosis, the single intradermal tuberculin test or the single comparative intradermal tuberculin test, and the gamma-interferon test, which is regarded as an ancillary test, are used. Postmortem examination can identify granulomatous lesions compatible with a diagnosis of TB. In contrast, smears of the lesions can be stained for acid-fast bacilli, and samples of the affected organs can be subjected to histopathological analyses. Culture is the gold standard test for isolating mycobacterial bacilli because it has high sensitivity and specificity compared with other methods. Serology for antibody detection allows the testing of many samples simply, rapidly, and inexpensively, and the protocol can be standardized in different laboratories. Molecular biological analyses are also applicable to trace the epidemiology of the disease. In conclusion, reviewing the various techniques used in MTBC diagnosis can help establish guidelines for researchers when choosing a particular diagnostic method depending on the situation at hand, be it disease outbreaks in wildlife or for epidemiological studies. This is because a good understanding of various diagnostic techniques will aid in monitoring and managing emerging pandemic threats of infectious diseases from wildlife and also preventing the potential spread of zoonotic TB to livestock and humans. This review aimed to provide up-to-date information on different techniques used for diagnosing TB at the interfaces between wildlife, livestock, and humans.
  4. Fulltext A case report: Community-acquired Pseudomonas aeruginosa necrotizing fasciitis in a morbidly obese diabetic young man can be fatal
    Mazlan MZ, Zainal Abidin H, Wan Hassan WMN, Nik Mohamad NA, Salmuna ZN, Ibrahim K, et al.
    IDCases, 2020;22:e01001.
    PMID: 33204633 DOI: 10.1016/j.idcr.2020.e01001
    We present a case study of a 26-year-old morbidly obese man with a three-day history of right leg pain and swelling. The swelling was associated with low grade fever. He was alert and conscious upon presentation to the hospital. His physical examination showed gross swelling of the entire right lower limb with no systemic manifestations. There was no discharge and bullae from the swelling area of the leg. He had high blood sugar and was newly diagnosed with type 2 diabetes mellitus. He was diagnosed with necrotizing fasciitis. An intravenous imipenem-cilastatin 500 mg every 6 h together with clindamycin 900 mg every 8 h was started empirically. Extensive wound debridement was performed. The swab culture obtained intraoperatively grew Pseudomonas aeruginosa. He required an above knee amputation due to worsening infection despite wound debridement. Post-operatively, he developed acute kidney injury with severe metabolic acidosis, which required daily hemodialysis. However, the patient deteriorated due to septic shock with multi-organ failure, resulting in his death.
  5. Extracellular Vesicles Derived From Colorectal Cancer Affects CD8 T Cells: An Analysis Based on Body Mass Index
    Abu N, Othman N, Ab Razak NS, Bakarurraini NAAR, Nasir SN, Soh JEC, et al.
    Front Cell Dev Biol, 2020;8:564648.
    PMID: 33324632 DOI: 10.3389/fcell.2020.564648
    Colorectal cancer (CRC) is one of the most widely diagnosed cancers worldwide. It has been shown that the body-mass index (BMI) of the patients could influence the tumor microenvironment, treatment response, and overall survival rates. Nevertheless, the mechanism on how BMI affects the tumorigenesis process, particularly the tumor microenvironment is still elusive. Herein, we postulate that extracellular vesicles (EVs) from CRC patients and non-CRC volunteers with different BMI could affect immune cells differently, in CD8 T cells particularly. We isolated the EVs from the archived serum of CRC patients with high and low BMI, as well as healthy controls with similar BMI status. The EVs were further characterized via electron microscopy, western blot and dynamic light scattering. Then, functional analysis was performed on CD8 T cells including apoptosis, cell proliferation, gene expression profiling and cytokine release upon co-incubation with the different EVs. Our results suggest that CRC-derived EVs were able to regulate the CD8 T cells. In some assays, low BMI EVs were functionally different than high BMI EVs. This study highlights the possible difference in the regulatory mechanism of cancer patients-derived EVs, especially on CD8 T cells.
  6. Postoperative Maladaptive Behavior, Preoperative Anxiety and Emergence Delirium in Children Undergone General Anesthesia: A Narrative Review
    Zainal Abidin H, Omar SC, Mazlan MZ, Hassan MH, Isa R, Ali S, et al.
    Glob Pediatr Health, 2021;8:2333794X211007975.
    PMID: 33889680 DOI: 10.1177/2333794X211007975
    Over the years, the number of pediatric patients undergoing surgeries are increasing steadily. The types of surgery vary between elective to emergency with involvement of multidisciplinary teams. The development of day care surgery unit is expanding where the patients will only come to the hospital on the day of surgery and discharge home after such as satisfactory parameters achieved, minimal to no pain, minimal to no bleeding from surgical site and able to tolerate fluids. Hospitalization and surgery could contribute to significant psychological disturbance to the children. These issues are not being addressed as children have difficulty in conveying their problems and fear. They do however express it through negative behavioral changes.
  7. Fulltext Global metabolomics profiling of colorectal cancer in Malaysian patients
    Amir Hashim NA, Ab-Rahim S, Wan Ngah WZ, Nathan S, Ab Mutalib NS, Sagap I, et al.
    Bioimpacts, 2021;11(1):33-43.
    PMID: 33469506 DOI: 10.34172/bi.2021.05
    Introduction:
    The serum metabolomics approach has been used to identify metabolite biomarkers that can diagnose colorectal cancer (CRC) accurately and specifically. However, the biomarkers identified differ between studies suggesting that more studies need to be performed to understand the influence of genetic and environmental factors. Therefore, this study aimed to identify biomarkers and affected metabolic pathways in Malaysian CRC patients.
    Methods:
    Serum from 50 healthy controls and 50 CRC patients were collected at UKM Medical Centre. The samples were deproteinized with acetonitrile and untargeted metabolomics profile determined using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOFMS, Agilent USA). The data were analysed using Mass Profiler Professional (Agilent, USA) software. The panel of biomarkers determined were then used to identify CRC from a new set of 20 matched samples.
    Results:
    Eleven differential metabolites were identified whose levels were significantly different between CRC patients compared to normal controls. Based on the analysis of the area under the curve, 7 of these metabolites showed high sensitivity and specificity as biomarkers. The use of the 11 metabolites on a new set of samples was able to differentiate CRC from normal samples with 80% accuracy. These metabolites were hypoxanthine, acetylcarnitine, xanthine, uric acid, tyrosine, methionine, lysoPC, lysoPE, citric acid, 5-oxoproline, and pipercolic acid. The data also showed that the most perturbed pathways in CRC were purine, catecholamine, and amino acid metabolisms.
    Conclusion:
    Serum metabolomics profiling can be used to identify distinguishing biomarkers for CRC as well as to further our knowledge of its pathophysiological mechanisms.
  8. Fulltext Microstructural behavior of magnetorheological elastomer undergoing durability evaluation by stress relaxation
    Johari MAF, Mazlan SA, Nasef MM, Ubaidillah U, Nordin NA, Aziz SAA, et al.
    Sci Rep, 2021 May 25;11(1):10936.
    PMID: 34035434 DOI: 10.1038/s41598-021-90484-0
    The widespread use of magnetorheological elastomer (MRE) materials in various applications has yet to be limited due to the fact that there are substantial deficiencies in current experimental and theoretical research on its microstructural durability behavior. In this study, MRE composed of silicon rubber (SR) and 70 wt% of micron-sized carbonyl iron particles (CIP) was prepared and subjected to stress relaxation evaluation by torsional shear load. The microstructure and particle distribution of the obtained MRE was evaluated by a field emission scanning electron microscopy (FESEM). The influence of constant low strain at 0.01% is the continuing concern within the linear viscoelastic (LVE) region of MRE. Stress relaxation plays a significant role in the life cycle of MRE and revealed that storage modulus was reduced by 8.7%, normal force has weakened by 27%, and stress performance was reduced by 6.88% along approximately 84,000 s test duration time. This time scale was the longest ever reported being undertaken in the MRE stress relaxation study. Novel micro-mechanisms that responsible for the depleted performance of MRE was obtained by microstructurally observation using FESEM and in-phase mode of atomic force microscope (AFM). Attempts have been made to correlate strain localization produced by stress relaxation, with molecular deformation in MRE amorphous matrix. Exceptional attention was focused on the development of molecular slippage, disentanglement, microplasticity, microphase separation, and shear bands. The relation between these microstructural phenomena and the viscoelastic properties of MRE was diffusely defined and discussed. The presented MRE is homogeneous with uniform distribution of CIP. The most significant recent developments of systematic correlation between the effects of microstructural deformation and durability performance of MRE under stress relaxation has been observed and evaluated.
  9. 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.
  10. Fulltext Antituberculosis Targeted Drug Delivery as a Potential Future Treatment Approach
    Mazlan MKN, Mohd Tazizi MHD, Ahmad R, Noh MAA, Bakhtiar A, Wahab HA, et al.
    Antibiotics (Basel), 2021 Jul 25;10(8).
    PMID: 34438958 DOI: 10.3390/antibiotics10080908
    Mycobacterium tuberculosis (Mtb) is the microorganism that causes tuberculosis. This infectious disease has been around for centuries, with the earliest record of Mtb around three million years ago. The discovery of the antituberculosis agents in the 20th century has managed to improve the recovery rate and reduce the death rate tremendously. However, the conventional antituberculosis therapy is complicated by the development of resistant strains and adverse drug reactions experienced by the patients. Research has been conducted continuously to discover new, safe, and effective antituberculosis drugs. In the last 50 years, only two molecules were approved despite laborious work and costly research. The repurposing of drugs is also being done with few drugs; antibiotics, particularly, were found to have antituberculosis activity. Besides the discovery work, enhancing the delivery of currently available antituberculosis drugs is also being researched. Targeted drug delivery may be a potentially useful approach to be developed into clinically accepted treatment modalities. Active targeting utilizes a specifically designed targeting agent to deliver a chemically conjugated drug(s) towards Mtb. Passive targeting is very widely explored, with the development of multiple types of nanoparticles from organic and inorganic materials. The nanoparticles will be engulfed by macrophages and this will eliminate the Mtb that is present in the macrophages, or the encapsulated drug may be released at the sites of infections that may be in the form of intra- and extrapulmonary tuberculosis. This article provided an overview on the history of tuberculosis and the currently available treatment options, followed by discussions on the discovery of new antituberculosis drugs and active and passive targeting approaches against Mycobacterium tuberculosis.
  11. Fulltext High Granulocyte-Macrophage Colony Stimulating Factor to Interleukin 10 Ratio and Marked Antioxidant Enzyme Activities Predominate in Symptomatic Cattle Naturally Infected with Candidatus Mycoplasma haemobos, Theileria orientalis, Theileria sinensis and Trypanosoma evansi
    Agina OA, Cheah KT, Sayuti NSA, Shaari MR, Isa NMM, Ajat M, et al.
    Animals (Basel), 2021 Jul 29;11(8).
    PMID: 34438696 DOI: 10.3390/ani11082235
    The aim of this study was to measure the serum proinflammatory (IL-12, GM-CSF & IFN-γ) to anti-inflammatory (IL-10, IL-4) cytokine ratio, oxidant (MDA) level and antioxidant enzyme (SOD; GPx) activities after blood parasite infections. The blood and serum samples were obtained from 130 cattle and screened for identity of the infecting blood parasites by conventional PCR. The following blood parasite species were detected: Candidatus Mycoplasma haemobos (70/130); Theileria orientalis (65/130); Theileria sinensis (32/130); Anaplasma marginale (49/130); Anaplasma platys (7/130); and Trypanosoma evansi (4/130). The GM-CSF/IL-10 ratio showed significantly higher values in all the symptomatic blood parasite infected cattle groups except for symptomatic A. platys infected cattle groups. Anti-inflammatory cytokine immune responses were notable findings in symptomatic and asymptomatic cattle infected with C. M. haemobos and T. orientalis characterized by low serum IL-12:IL-10, IFN-γ:IL-10, IL-12:IL-4 and IFN-γ:IL-4 (p < 0.05). Therefore, high serum GM-CSF:IL:10 in the symptomatic blood parasite infected cattle, low serum IL-12:IL-10, IFN-γ:IL-10, IL-12:IL-4 and IFN-γ:IL-4 ratios in asymptomatic cattle, high MDA level, and increased antioxidant enzyme activities could be useful predictive tools for outcome of natural blood parasite infections in cattle.
  12. Fulltext An Insight into Amorphous Shear Band in Magnetorheological Solid by Atomic Force Microscope
    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.
  13. Fulltext Acute bacteremic pneumonia due to melioidosis developing in the intensive care setting
    Zainal Abidin H, Muhd Besari A, Nadarajan C, Wan Shukeri WF, Mazlan MZ, Chong SE, et al.
    IDCases, 2017;8:63-65.
    PMID: 28417070 DOI: 10.1016/j.idcr.2017.03.010
    In Malaysia, melioidosis is commonly encountered as this infection is known as part of the endemic area for the disease. Managing cases of positive Burkholderia pseudomallei infection can involve multidisciplinary unit mainly, microbiologist, infectious disease team and intensive care as it may be quite difficult to distinguish melioidosis from a number of other diseases on the clinical setting alone. Laboratory diagnosis plays a vital role in determining the direction of management. Investigations such as culture, polymerase chain reaction (PCR) and serology should be evaluated once the disease is suspected. In this particular case, the patient is a young adult involved in a road traffic accident. Unlike any other cases with melioidosis, he had no potential risk factors which may have contributed to the severity of the disease and it is likely that the site of the accident was the source of acquisition of this gram negative bacterium.
  14. Fulltext The positive expression of genotype VII Newcastle disease virus (Malaysian isolate) in Japanese quails (Coturnix coturnix japonica)
    Mazlan LF, Bachek NF, Mahamud SNA, Idris LH, Wei TS, Omar AR, et al.
    Vet World, 2017 May;10(5):542-548.
    PMID: 28620260 DOI: 10.14202/vetworld.2017.542-548
    AIM: Genotype VII Newcastle disease virus (NDV) is the most predominant NDV strains that circulating in Malaysia; thus, this study was aimed to determine the susceptibility of Japanese quails toward genotype VII NDV. Clinical signs, gross pathological lesions of organs, positive detection of virus in organs and cloacal swabs, as well as the expression of the antibody titer, were used as parameters to assess the susceptibility of Japanese quails following infection of genotype VII NDV.

    MATERIALS AND METHODS: About 20 quails were divided into three groups (n=8 for Groups A and B; n=4 for the control group). The quails in the Groups A and B were infected via intraocular route with 0.03 ml of 103.5 ELD50 and 107.0 ELD50 of NDV strain IBS 002, respectively, while the control group received 1× phosphate-buffered saline. Cloacal swabs and necropsy were taken on day 7 post-infection for all quails were subjected to one-step reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) for detection of virus and examination for gross pathological lesion, respectively. Blood serums of infected quails were taken on day 10, 14, and 21 post-day infections and were subjected for hemagglutination inhibition (HI) assay.

    RESULTS: Depression and ruffled feathers, trachea rales, leg paralysis, and torticollis were shown in some of the quails in both infected groups. Based on statistical analysis, there was no significant difference (p>0.05) in clinical signs between the infected groups. The results for RT-qPCR were found to be negative for all groups, and no gross pathological lesions of organs observed for quails in both infected groups. Trachea, proventriculus, and cecal tonsil were taken for the detection of NDV by RT-qPCR, and some of the organ samples showed positive detection of virus in both infected groups. HI assay showed an increase in mean titers of antibody across time and between infected groups.

    CONCLUSION: In summary, Japanese quails are susceptible to genotype VII NDV based on parameters assessed.

  15. 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.
  16. 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.
  17. Acrylic-based genosensor utilizing metal salphen labeling approach for reflectometric dengue virus detection
    Mazlan NF, Tan LL, Karim NHA, Heng LY, Jamaluddin ND, Yusof NYM, et al.
    Talanta, 2019 Jun 01;198:358-370.
    PMID: 30876573 DOI: 10.1016/j.talanta.2019.02.036
    An optical genosensor based on Schiff base complex (Zn2+ salphen) DNA label and acrylic microspheres (AMs) as polymer support of the capturing DNA probe (cpDNA) was developed for dengue virus serotype 2 (DEN-2) detection via reflectance spectrophotometric method. The solid-state optical DNA biosensor showed high selectivity and specificity up to one-base mismatch in the target DNA sequence owing to the salphen chemical structure that is rich in localized electrons, and allowed π-π stacking interaction between stacked base pairs of double-stranded DNA (dsDNA). The reflectometric DNA microsensor demonstrated a broad linear detection range towards DEN-2 DNA from 1 × 10-15 M to 1 × 10-3 M with a low limit of detection (LOD) obtained at 1.21 × 10-16 M. The DNA biosensor gave reproducible optical response with a satisfactory relative standard deviation (RSD) at 3.1%, (n = 3), and the reflectance response was stable even after four regeneration cycles of the DNA biosensor. The optical genosensor was proven comparable with standard reverse transcription polymerase chain reaction (RT-PCR) in detecting DEN-2 genome acquired from clinical samples of serum, urine and saliva of dengue virus infected patients under informed consent. The developed reflectometric DNA biosensor is advantageous in offering an early DEN-2 diagnosis, when fever symptom started to manifest in patient.
  18. Fulltext Sandwich-Type DNA Micro-Optode Based on Gold-Latex Spheres Label for Reflectance Dengue Virus Detection
    Jeningsih, Tan LL, Ulianas A, Heng LY, Mazlan NF, Jamaluddin ND, et al.
    Sensors (Basel), 2020 Mar 25;20(7).
    PMID: 32218202 DOI: 10.3390/s20071820
    A DNA micro-optode for dengue virus detection was developed based on the sandwich hybridization strategy of DNAs on succinimide-functionalized poly(n-butyl acrylate) (poly(nBA-NAS)) microspheres. Gold nanoparticles (AuNPs) with an average diameter of ~20 nm were synthesized using a centrifugation-based method and adsorbed on the submicrometer-sized polyelectrolyte-coated poly(styrene-co-acrylic acid) (PSA) latex particles via an electrostatic method. The AuNP-latex spheres were attached to the thiolated reporter probe (rDNA) by Au-thiol binding to functionalize as an optical gold-latex-rDNA label. The one-step sandwich hybridization recognition involved a pair of a DNA probe, i.e., capture probe (pDNA), and AuNP-PSA reporter label that flanked the target DNA (complementary DNA (cDNA)). The concentration of dengue virus cDNA was optically transduced by immobilized AuNP-PSA-rDNA conjugates as the DNA micro-optode exhibited a violet hue upon the DNA sandwich hybridization reaction, which could be monitored by a fiber-optic reflectance spectrophotometer at 637 nm. The optical genosensor showed a linear reflectance response over a wide cDNA concentration range from 1.0 × 10-21 M to 1.0 × 10-12 M cDNA (R2 = 0.9807) with a limit of detection (LOD) of 1 × 10-29 M. The DNA biosensor was reusable for three consecutive applications after regeneration with mild sodium hydroxide. The sandwich-type optical biosensor was well validated with a molecular reverse transcription polymerase chain reaction (RT-PCR) technique for screening of dengue virus in clinical samples, e.g., serum, urine, and saliva from dengue virus-infected patients under informed consent.
  19. Colorectal screening using the immunochemical faecal occult blood test kit among the Malaysian cohort participants
    Abdullah N, Abd Jalal N, Ismail N, Kamaruddin MA, Abd Mutalib NS, Alias MR, et al.
    Cancer Epidemiol, 2020 04;65:101656.
    PMID: 31923638 DOI: 10.1016/j.canep.2019.101656
    BACKGROUND: There has been a rapid increase in colorectal cancer (CRC) cases in Asian countries, including Malaysia. CRC is usually diagnosed at a late stage, and early detection of CRC is vital in improving survival. This study was conducted to determine the uptake rate of the immunochemical faecal occult blood test (iFOBT), the response rate to colonoscopy, and the CRC detection rate. We also wanted to identify the association between colorectal neoplasia and the Asia Pacific Colorectal Cancer Screening (APCS) scoring system.

    METHODS: We recruited 2264 individuals from The Malaysian Cohort participants aged 35-65 years who consented to colorectal screening using the iFOBT kit from July 2017 until January 2019.

    RESULTS: The response rate and positive iFOBT test rate of this study were 79.6% and 13.1% respectively. Among those with positive results, 125 individuals (52.7%) underwent colonoscopy; CRC was detected in six of them while 45 others (36.0%) had polyps. The overall CRC detection rate was 0.3% while the colorectal neoplasia detection rate (both colorectal cancer and colorectal polyps) was 2.3%. The APCS scoring indicated a significant association with colorectal neoplasia risk, with increasing trend by severity from moderate to high risk (3.46-11.14) compared to low risk. Most of the participants who were positive for iFOBT were those at high risk.

    CONCLUSIONS: The awareness of CRC risk and iFOBT screening are important strategies for early detection of CRC. We showed a CRC detection rate of 0.3 % among those who volunteered to have the iFOBT screening.

  20. Non-parametric multiple inputs prediction model for magnetic field dependent complex modulus of magnetorheological elastomer
    Saharuddin KD, Ariff MHM, Bahiuddin I, Ubaidillah U, Mazlan SA, Aziz SAA, et al.
    Sci Rep, 2022 Feb 17;12(1):2657.
    PMID: 35177686 DOI: 10.1038/s41598-022-06643-4
    This study introduces a novel platform to predict complex modulus variables as a function of the applied magnetic field and other imperative variables using machine learning. The complex modulus prediction of magnetorheological (MR) elastomers is a challenging process, attributable to the material's highly nonlinear nature. This problem becomes apparent when considering various possible fabrication parameters. Furthermore, traditional parametric modeling methods are limited when applied to solve larger-scale cases involving large databases. Consequently, the application of non-parametric modeling such as machine learning has gained increasing attraction in recent years. Therefore, this work proposes a data-driven approach for predicting multiple input-dependent complex moduli using feedforward neural networks. Besides excitation frequency and magnetic flux density as operating conditions, the inputs consider compositions and curing conditions represented by magnetic particle weight percentage and the curing magnetic field, respectively. Extreme learning machines and artificial neural networks were used to train the models. The simulation results obtained at various curing conditions and other inputs confirm that the predicted complex modulus has high accuracy with an R2 of about 0.997, as compared to the experimental results. Furthermore, the predicted complex modulus pattern and magnetorheological effect agree with the experimental data using both the learned and unlearned data.
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