Displaying publications 21 - 39 of 39 in total

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  1. Mohd Azmi UZ, Yusof NA, Kusnin N, Abdullah J, Suraiya S, Ong PS, et al.
    Sensors (Basel), 2018 Nov 14;18(11).
    PMID: 30441776 DOI: 10.3390/s18113926
    A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of tuberculosis biomarker 10-kDa culture filtrate protein (CFP10). The prepared GP/PANI nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and FESEM coupled with energy dispersive X-ray spectroscopy, respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced about five times compared with bare SPGE. Differential pulse voltammetry was used to detect the CFP10 antigen. The GP/PANI-modified SPGE that was fortified with sandwich type immunosensor exhibited a wide linear range (20⁻100 ng/mL) with a low detection limit of 15 ng/mL. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid and disposable, which is suitable for tuberculosis detection in real samples.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  2. Ibrahim Z, Amin MF, Yahya A, Aris A, Muda K
    Water Sci Technol, 2010;61(5):1279-88.
    PMID: 20220250 DOI: 10.2166/wst.2010.021
    Textile wastewater, one of the most polluted industrial effluents, generally contains substantial amount of dyes and chemicals that will cause increase in the COD, colour and toxicity of receiving water bodies if not properly treated. Current treatment methods include chemical and biological processes; the efficiency of the biological treatment method however, remains uncertain since the discharged effluent is still highly coloured. In this study, granules consisting mixed culture of decolourising bacteria were developed and the physical and morphological characteristics were determined. After the sixth week of development, the granules were 3-10 mm in diameter, having good settling property with settling velocity of 70 m/h, sludge volume index (SVI) of 90 to 130 mL/g, integrity coefficient of 3.7, and density of 66 g/l. Their abilities to treat sterilised raw textile wastewater were evaluated based on the removal efficiencies of COD (initial ranging from 200 to 3,000 mg/L), colour (initial ranging from 450 to 2000 ADMI) of sterilised raw textile wastewater with pH from 6.8 to 9.4. Using a sequential anaerobic-aerobic treatment cycle with hydraulic retention time (HRT) of 24 h, maximum removal of colour and COD achieved was 90% and 80%, respectively.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  3. Kapitonova MY, Muid S, Froemming GR, Yusoff WN, Othman S, Ali AM, et al.
    Malays J Pathol, 2012 Dec;34(2):103-13.
    PMID: 23424772 MyJurnal
    Microgravity, hypergravity, vibration, ionizing radiation and temperature fluctuations are major factors of outer space flight affecting human organs and tissues. There are several reports on the effect of space flight on different human cell types of mesenchymal origin while information regarding changes to vascular endothelial cells is scarce. Ultrastructural and cytophysiological features of macrovascular endothelial cells in outer space flight and their persistence during subsequent culturing were demonstrated in the present investigation. At the end of the space flight, endothelial cells displayed profound changes indicating cytoskeletal lesions and increased cell membrane permeability. Readapted cells of subsequent passages exhibited persisting cytoskeletal changes, decreased metabolism and cell growth indicating cellular senescence.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  4. Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Molecules, 2012 Feb 16;17(2):1969-91.
    PMID: 22343368 DOI: 10.3390/molecules17021969
    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  5. Torey A, Sasidharan S
    Eur Rev Med Pharmacol Sci, 2011 Aug;15(8):875-82.
    PMID: 21845797
    Candida (C.) albicans infection in its biofilm mode of growth has taken centre point with the increasing recognition of its role in human infections due to the development of resistance to the commonly used antibiotic or phenotypic adaptation within the biofilm. Hence, in this study the inhibitory effect of methanol extract of Cassia (C.) spectabilis leaves was evaluated against biofilm forming C. albicans.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  6. Kirubakari B, Chen Y, Sasidharan S
    PMID: 31113347 DOI: 10.2174/1871523018666190522112902
    BACKGROUND: Polyalthia longifolia is a popular medicinal plant and has been widely used as a traditional remedy for centuries in curing of various ailments. The purpose of this study was conducted to determine the in situ antimicrobial synergistic effects between Polyalthia longifolia leaf ethyl acetate fraction (PLEAF) and ampicillin against MRSA local isolate by using modern microscopy technique.

    METHODS: Hence, the evaluation of the synergistic activity of PLEAF and ampicillin against MRSA local isolate was conducted with scanning electron microscopy (SEM).

    RESULTS: The combinational effect of PLEAF fraction and ampicillin exhibited significant antibacterial activity against MRSA. Bacterial cells observations showed invagination, impaired cell division, extensive wrinkles, cell shrinkage, the appearance of a rougher cell with fibrous matrix and clustered cells which confirmed the synergistic effect of PLEAF and ampicillin against MRSA local isolate by SEM.

    CONCLUSION: Conclusively, the in situ SEM observation proved the synergistic antimicrobial activity between PLEAF fraction and ampicillin to destroy the MRSA resistance bacteria which is an important aspect of PLEAF fraction to be used in the future combinational therapy.

    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  7. Shanmugapriya, Vijayarathna S, Sasidharan S
    Microsc Microanal, 2019 10;25(5):1263-1272.
    PMID: 31383043 DOI: 10.1017/S1431927619014776
    Several microscopy methods have been developed to assess the morphological changes in cells in the investigations of the mode of cell death in response to a stimulus. Our recent finding on the treatment of the IC50 concentration (26.67 μg/mL) of Polyalthia longifolia leaf extract indicated the induction of apoptotic cell death via the regulation of miRNA in HeLa cells. Hence, the current study was conducted to validate the function of these downregulated microRNAs in P. longifolia-treated HeLa cells using microscopic approaches. These include scanning electron microscope (SEM), transmission electron microscope (TEM), and acridine orange/propidium iodide (AO/PI)-based fluorescent microscopy techniques by observing the morphological alterations to cells after transfection with mimic miRNA. Interestingly, the morphological changes observed in this study demonstrated the apoptotic hallmarks, for instance, cell blebbing, cell shrinkage, cytoplasmic and nuclear condensation, vacuolization, cytoplasmic extrusion, and the formation of apoptotic bodies, which proved the role of dysregulated miRNAs in apoptotic HeLa cell death after treatment with the P. longifolia leaf extract. Conclusively, the current study proved the crucial role of downregulated miR-484 and miR-221-5p in the induction of apoptotic cell death in P. longifolia-treated HeLa cells using three approaches-SEM, TEM, and AO/PI-based fluorescent microscope.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  8. Daffalla SB, Mukhtar H, Shaharun MS
    PLoS One, 2020;15(12):e0243540.
    PMID: 33275643 DOI: 10.1371/journal.pone.0243540
    Rice husk is a base adsorbent for pollutant removal. It is a cost-effective material and a renewable resource. This study provides the physicochemical characterization of chemically and thermally treated rice husk adsorbents for phenol removal from aqueous solutions. We revealed new functional groups on rice husk adsorbents by Fourier transform infrared spectroscopy, and observed major changes in the pore structure (from macro-mesopores to micro-mesopores) of the developed rice husk adsorbents using scanning electron microscopy. Additionally, we studied their surface area and pore size distribution, and found a greater enhancement of the morphological structure of the thermally treated rice husk compared with that chemically treated. Thermally treated adsorbents presented a higher surface area (24-201 m2.g-1) than those chemically treated (3.2 m2.g-1). The thermal and chemical modifications of rice husk resulted in phenol removal efficiencies of 36%-64% and 28%, respectively. Thus, we recommend using thermally treated rice husk as a promising adsorbent for phenol removal from aqueous solutions.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  9. Gantait S, Sinniah UR, Suranthran P, Palanyandy SR, Subramaniam S
    Protoplasma, 2015 Jan;252(1):89-101.
    PMID: 24893588 DOI: 10.1007/s00709-014-0660-x
    In the present study, polyembryoids of oil palm (Elaeis guineensis Jacq.) were cryopreserved with successful revival of 68 % for the first time using the droplet vitrification technique. Excised polyembryoids (3-5-mm diameter) from 3-month-old in vitro cultures were pre-cultured for 12 h in liquid Murashige and Skoog medium supplemented with 0.5 M sucrose. The polyembryoids were osmoprotected in loading solution [10% (w/v) dimethyl sulphoxide (DMSO) plus 0.7 M sucrose] for 30 min at room temperature and then placed on aluminium strips where they were individually drenched in chilled droplets of vitrification solution (PVS2) [30% (w/v) glycerol plus 15% (w/v) ethylene glycol (EG) plus 15% (w/v) DMSO plus 0.4 M sucrose] for 10 min. The aluminium strips were enclosed in cryovials which were then plunged quickly into liquid nitrogen and kept there for 1 h. The polyembryoids were then thawed and unloaded (using 1.2 M sucrose solution) with subsequent transfer to regeneration medium and stored in zero irradiance. Following for 10 days of storage, polyembryoids were cultured under 16 h photoperiod of 50 μmol m(-2) s(-1) photosynthetic photon flux density, at 23 ± 1 °C. Post-thaw growth recovery of 68% was recorded within 2 weeks of culture, and new shoot development was observed at 4 weeks of growth. Scanning electron microscopy revealed that successful regeneration of cryopreserved polyembryoids was related to maintenance of cellular integrity, presumably through PVS2 exposure for 10 min. The present study demonstrated that cryopreservation by droplet vitrification enhanced the regeneration percentages of oil palm in comparison with the conventional vitrification method previously reported.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  10. Wan Ismail WZ, Sim KS, Tso CP, Ting HY
    Scanning, 2011 Jul-Aug;33(4):233-51.
    PMID: 21611953 DOI: 10.1002/sca.20237
    To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  11. Sim KS, Kiani MA, Nia ME, Tso CP
    J Microsc, 2014 Jan;253(1):1-11.
    PMID: 24164248 DOI: 10.1111/jmi.12089
    A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  12. Sim KS, Ting HY, Lai MA, Tso CP
    J Microsc, 2009 Jun;234(3):243-50.
    PMID: 19493101 DOI: 10.1111/j.1365-2818.2009.03167.x
    An improvement to the previously proposed Canny optimization technique for scanning electron microscope image colorization is reported. The additional process is adaptive tuning, where colour tuning is performed adaptively, based on comparing the original luminance values with calculated luminance values. The complete adaptive Canny optimization technique gives significantly better mechanical contrast on scanning electron microscope grey-scale images than do existing methods.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  13. Sim KS, Thong LW, Ting HY, Tso CP
    J Microsc, 2010 Feb;237(2):111-8.
    PMID: 20096041 DOI: 10.1111/j.1365-2818.2009.03325.x
    Interpolation techniques that are used for image magnification to obtain more useful details of the surface such as morphology and mechanical contrast usually rely on the signal information distributed around edges and areas of sharp changes and these signal information can also be used to predict missing details from the sample image. However, many of these interpolation methods tend to smooth or blur out image details around the edges. In the present study, a Lagrange time delay estimation interpolator method is proposed and this method only requires a small filter order and has no noticeable estimation bias. Comparing results with the original scanning electron microscope magnification and results of various other interpolation methods, the Lagrange time delay estimation interpolator is found to be more efficient, more robust and easier to execute.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  14. Sim KS, Law KK, Tso CP
    Microsc Res Tech, 2007 Nov;70(11):919-27.
    PMID: 17661362
    A new filter is developed for the enhancement of scanning electron microscope (SEM) images. A mixed Lagrange time delay estimation auto-regression (MLTDEAR)-based interpolator is used to provide an estimate of noise variance to a standard Wiener filter. A variety of images are captured and the performance of the filter is shown to surpass the conventional noise filters. As all the information required for processing is extracted from a single image, this method is not constrained by image registration requirements and thus can be applied in real-time in cases where specimen drift is presented in the SEM image.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  15. Ahmad M, Zafar M, Sultana S, Ahmad M, Abbas Q, Ayoub M, et al.
    Microsc Res Tech, 2018 Sep;81(9):1004-1016.
    PMID: 30303585 DOI: 10.1002/jemt.23066
    Pollen micro-morphological features have proven to be helpful for the plant taxonomists in the identification and classification of plants. The utilization of this plantmayhelpfulin the areas of lignocellulosic conversion to biofuels and diversify application toward biomass. The current study was planned with the aim to evaluate the pollen features of complex Ranunculaceous flora of District Chitral, Northern Pakistan using both scanning electron microscopy (SEM) and Light Microscope (LM) for their taxonomic importance. Pollens of 18 Ranunculaceous species belonging to 6 genera were collected from different localities of the research area. SEM and LM were used to examine both qualitative and quantitative micro-morphological features. Sculptring of the sexine include; Scabrate, psilate, echinate, verrucate, perforate gemmate, and reticulate and so forth. Shape of the pollens was sub-spheroidal, spheroidal, prolate, subprolate and oblate and so forth. Type of pollen was ranged from mono to tricolpate and tricolporate. Quantitative characters include length/width of the pollen, colpus, exine thickness, and P/E ratio. Based on these micro-morphological features a taxonomic key was prepared for the fast and correct identification. RESEARCH HIGHLIGHT: Study of the pollen micro-morphological features of Ranunculaceous species by SEM and LM. Analysing both qualitative and quantitative characters of the pollens. Preparation of taxonomic key based on micro-morphological features for the correct and fast identification.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  16. Chai WL, Moharamzadeh K, Brook IM, Van Noort R
    Biotech Histochem, 2011 Aug;86(4):242-54.
    PMID: 20392135 DOI: 10.3109/10520291003707916
    The success of dental implant treatment depends on the healing of both hard and soft tissues. While osseointegration provides initial success, the biological seal of the peri-implant soft tissue is crucial for maintaining the long term success of implants. Most studies of the biological seal of peri-implant tissues are based on animal or monolayer cell culture models. To understand the mechanisms of soft tissue attachment and the factors affecting the integrity of the soft tissue around the implants, it is essential to obtain good quality histological sections for microscopic examination. The nature of the specimens, however, which consist of both metal implant and soft peri-implant tissues, poses difficulties in preparing the specimens for histomorphometric analysis of the implant-soft tissue interface. We review various methods that have been used for the implant-tissue interface investigation with particular focus on the soft tissue. The different methods are classified and the advantages and limitations of the different techniques are highlighted.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods*
  17. Shahrokh Abadi MH, Hamidon MN, Shaari AH, Abdullah N, Wagiran R
    Sensors (Basel), 2011;11(8):7724-35.
    PMID: 22164041 DOI: 10.3390/s110807724
    A gas sensor array was developed in a 10 × 10 mm(2) space using Screen Printing and Pulse Laser Ablation Deposition (PLAD) techniques. Heater, electrode, and an insulator interlayer were printed using the screen printing method on an alumina substrate, while tin oxide and platinum films, as sensing and catalyst layers, were deposited on the electrode at room temperature using the PLAD method, respectively. To ablate SnO(2) and Pt targets, depositions were achieved by using a 1,064 nm Nd-YAG laser, with a power of 0.7 J/s, at different deposition times of 2, 5 and 10 min, in an atmosphere containing 0.04 mbar (4 kPa) of O(2). A range of spectroscopic diffraction and real space imaging techniques, SEM, EDX, XRD, and AFM were used in order to characterize the surface morphology, structure, and composition of the films. Measurement on the array shows sensitivity to some solvent and wood smoke can be achieved with short response and recovery times.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  18. Mohammed NJ, Othman NK, Taib MFM, Samat MH, Yahya S
    Molecules, 2021 Jun 09;26(12).
    PMID: 34207914 DOI: 10.3390/molecules26123535
    Extracts from plant materials have great potential as alternatives to inorganic corrosion inhibitors, which typically have harmful consequences. Experimental and theoretical methodologies studied the effectiveness of agricultural waste, namely, date palm seed extract as a green anti-corrosive agent in 0.5 M hydrochloric acid. Experimental results showed that immersion time and temperature are closely related to the effectivity of date palm seed as a corrosion inhibitor. The inhibition efficiency reduced from 95% to 91% at 1400 ppm when the immersion time was increased from 72 h to 168 h. The experimental results also indicated that the inhibition efficiency decreased as the temperature increased. The presence of a protective layer of organic matter was corroborated by scanning electron microscopy. The adsorption studies indicated that date palm seed obeyed Langmuir adsorption isotherm on the carbon steel surface, and Gibbs free energy values were in the range of -33.45 to -38.41 kJ·mol-1. These results suggested that the date palm seed molecules interacted with the carbon steel surface through mixture adsorption. Theoretical calculations using density functional theory showed that the capability to donate and accept electrons between the alloy surface and the date palm seed inhibitor molecules is critical for adsorption effectiveness. The HOMO and LUMO result indicated that the carboxyl (COOH) group and C=C bond were the most active sites for the electron donation-acceptance type of interaction and most auxiliary to the adsorption process over the Fe surface.
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
  19. Adzmi F, Meon S, Musa MH, Yusuf NA
    J Microencapsul, 2012;29(3):205-10.
    PMID: 22309479 DOI: 10.3109/02652048.2012.659286
    Microencapsulation is a process by which tiny parcels of an active ingredient are packaged within a second material for the purpose of shielding the active ingredient from the surrounding environment. This study aims to determine the ability of the microencapsulation technique to improve the viability of Trichoderma harzianum UPM40 originally isolated from healthy groundnut roots as effective biological control agents (BCAs). Alginate was used as the carrier for controlled release, and montmorillonite clay (MMT) served as the filler. The encapsulated Ca-alginate-MMT beads were characterised using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The FTIR results showed the interaction between the functional groups of alginate and MMT in the Ca-alginate-MMT beads. Peaks at 1595, 1420 and 1020 cm(-1) characterised alginate, and peaks at 1028 and 453 cm(-1) characterised MMT; both sets of peaks appeared in the Ca-alginate-MMT FTIR spectrum. The TGA analysis showed an improvement in the thermal stability of the Ca-alginate-MMT beads compared with the alginate beads alone. SEM analysis revealed a homogeneous distribution of the MMT particles throughout the alginate matrix. T. harzianum UPM40 was successfully encapsulated in the Ca-alginate-MMT beads. Storage analysis of the encapsulated T. harzianum UPM40 showed that the low storage temperature of 5°C resulted in significantly (p 
    Matched MeSH terms: Microscopy, Electron, Scanning/methods
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