Displaying publications 801 - 820 of 1298 in total

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  1. Performances of toluene removal by activated carbon derived from durian shell
    Tham YJ, Latif PA, Abdullah AM, Shamala-Devi A, Taufiq-Yap YH
    Bioresour Technol, 2011 Jan;102(2):724-8.
    PMID: 20884200 DOI: 10.1016/j.biortech.2010.08.068
    In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model.
    Matched MeSH terms: Microscopy, Electron, Scanning
  2. Zerumbone induces apoptosis in T-acute lymphoblastic leukemia cells
    Abdelwahab SI, Abdul AB, Mohan S, Taha MM, Syam S, Ibrahim MY, et al.
    Leuk. Res., 2011 Feb;35(2):268-71.
    PMID: 20708800 DOI: 10.1016/j.leukres.2010.07.025
    Zerumbone (ZER) is a potential anticancer natural compound, isolated from Zingiber zerumbet Smith. In this investigation, the anticancer properties of ZER were evaluated on cancer cells of T-acute lymphoblastic leukemia, CEM-ss. The results showed that ZER has cytotoxic effect against CEM-ss cells with an IC(50) of 8.4 ± 1.9 μg/ml (coefficient of variation < 30%). Comparatively, 5-fluorouracil (positive control), imposed an inhibitory effect on CEM-ss cells with an IC(50) of 1.94 ± 0.06 μg/ml. Scanning electron microscopy (SEM) results revealed abnormalities such as membrane blebbing, holes and cytoplasmic extrusions, all of which are characteristics of apoptosis. In addition, ZER has increased the number of TUNEL-positive stain and the cellular level of caspase-3, the hallmarks of apoptosis, on treated CEM-ss cells. It could be concluded that, ZER was able to produce apoptosis on T-acute lymphoblastic leukemia, CEM-ss. The current findings suggest that ZER might be helpful for improving the usefulness of anticancer agents in the therapy of leukemia.
    Matched MeSH terms: Microscopy, Electron, Scanning
  3. Incidence of microsporidia in cancer patients
    Lono AR, Kumar S, Chye TT
    J Gastrointest Cancer, 2008;39(1-4):124-9.
    PMID: 19459072 DOI: 10.1007/s12029-009-9065-z
    INTRODUCTION: Microsporidia are considered opportunistic pathogens as evidenced by the significant detection in immunocompromised HIV/AIDS population. Cancer patients receiving chemotherapy are considered to be immunosuppressed.

    MATERIALS AND METHODS: Stool samples were collected from 311 cancer patients in the Klang Valley. Each sample underwent water-ether concentration and staining with modified trichrome stain.

    RESULTS AND DISCUSSION: Sixty-eight samples were positive by oil immersion examination. Polymerase chain reaction amplification with specific primers on those samples amplified Encephalitozoon intestinalis from two of the samples and Encephalitozoon hellem from one sample.

    Matched MeSH terms: Microscopy, Electron, Transmission
  4. Preparation and characterization of tungsten-loaded titanium dioxide photocatalyst for enhanced dye degradation
    Saepurahman, Abdullah MA, Chong FK
    J Hazard Mater, 2010 Apr 15;176(1-3):451-8.
    PMID: 19969415 DOI: 10.1016/j.jhazmat.2009.11.050
    Tungsten-loaded TiO(2) photocatalyst has been successfully prepared and characterized. TEM analysis showed that the photocatalysts were nanosize with the tungsten species forming layers of coverage on the surface of TiO(2), but not in clustered form. This was confirmed by XRD and FT-Raman analyses where tungsten species were well dispersed at lower loading (<6.5 mol%), but were in crystalline WO(3) at higher loadings (>12 mol%). In addition, loading with tungsten could stabilize the anatase phase from transforming into inactive rutile phase and did not shift the optical absorption to the visible region as shown by DRUV-vis analysis. PZC value of TiO(2) was found at 6.4, but the presence of tungsten at 6.5 mol% WO(3), decreased the PZC value to 3. Tungsten-loaded TiO(2) was superior to unmodified TiO(2) with 2-fold increase in degradation rate of methylene blue, and equally effective for the degradation of different class of dyes such as methyl violet and methyl orange at 1 mol% WO(3) loading.
    Matched MeSH terms: Microscopy, Electron, Transmission
  5. Effect of preparation conditions of activated carbon from bamboo waste for real textile wastewater
    Ahmad AA, Hameed BH
    J Hazard Mater, 2010 Jan 15;173(1-3):487-93.
    PMID: 19765899 DOI: 10.1016/j.jhazmat.2009.08.111
    This study deals with the use of activated carbon prepared from bamboo waste (BMAC), as an adsorbent for the removal of chemical oxygen demand (COD) and color of cotton textile mill wastewater. Bamboo waste was used to prepare activated carbon by chemical activation using phosphoric acid (H(3)PO(4)) as chemical agent. The effects of three preparation variables activation temperature, activation time and H(3)PO(4):precursor (wt%) impregnation ratio on the color and COD removal were investigated. Based on the central composite design (CCD) and quadratic models were developed to correlate the preparation variables to the color and COD. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The optimum condition was obtained by using temperature of 556 degrees C, activation time of 2.33 h and chemical impregnation ratio of 5.24, which resulted in 93.08% of color and 73.98% of COD.
    Matched MeSH terms: Microscopy, Electron, Scanning
  6. Characterisation of microbial flocs formed from raw textile wastewater in aerobic biofilm reactor (ABR)
    Ibrahim Z, Amin MF, Yahya A, Aris A, Umor NA, Muda K, et al.
    Water Sci Technol, 2009;60(3):683-8.
    PMID: 19657163 DOI: 10.2166/wst.2009.440
    Microbial flocs formed from raw textile wastewater in a prototype Aerobic Biofilm Reactor (ABR) system were characterised and studied for their potential use in the treatment of textile wastewater. After 90-100 days of operation, microbial flocs of loose irregular structures were obtained from the reactor with good settling velocity of 33 m/h and sludge volume index (SVI) of 48.2 mL/g. Molecular analysis of the flocs using PCR-amplified 16S rDNA sequence showed 98% homology to those of Bacillus sp, Paenibacillus sp and Acromobacter sp. Detection of Ca(2+)(131 mg/g) and Fe(2+)(131 mg/g) using atomic absorption spectrometer might be implicated with the flocs formation. In addition, presence of Co(2+) and Ni(2+) were indicative of the flocs ability to accumulate at least a fraction of the metals' present in the wastewater. When the flocs were used for the treatment of raw textile wastewater, they showed good removal of COD and colour about 55% and 70% respectively, indicating their potential application.
    Matched MeSH terms: Microscopy, Electron, Scanning
  7. Remediation of sulfidic wastewater by catalytic oxidation with hydrogen peroxide
    Ahmad N, Maitra S, Dutta BK, Ahmad F
    J Environ Sci (China), 2009;21(12):1735-40.
    PMID: 20131606
    Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-Ray diffraction analysis, scanning electrom microscope and energy dispersive X-ray analysis. The catalyst was quite effective in oxidizing the sulfide by hydrogen peroxide. The effects of sulfide concentration, catalyst loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies for the catalytic oxidation reaction were calculated based on the experimental results.
    Matched MeSH terms: Microscopy, Electron, Scanning
  8. The formation and characterisation of an asymmetric nanofiltration membrane for ammonia-nitrogen removal: effect of shear rate
    Ali N, Halim NS, Jusoh A, Endut A
    Bioresour Technol, 2010 Mar;101(5):1459-65.
    PMID: 19786347 DOI: 10.1016/j.biortech.2009.08.070
    The focus of this research is to study the potential of nanofiltration membrane technology in removing ammonia-nitrogen from the aquaculture system. One of the major fabrication parameters that directly affect the separation performance is shear rate or casting rate during membrane fabrication. In this study, asymmetric polyethersulfone (PES) nanofiltration membranes were prepared at five different shear rates within the range of 67-400 s(-1). Membrane productivity and separation performance were assessed via pure water, salt and ammonia-nitrogen permeation experiments, and their structural properties were determined by employing the combination of the irreversible thermodynamic (IT) model, solution diffusion model, steric hindrance pore (SHP) model and Teorell-Meyers (TMS) model. The study reveals that the alteration of shear rate enormously affects the membrane morphology and structural parameters, hence subsequently significantly influencing the membrane performance. It was found that, membrane produced at the shear rate 200 s(-1) or equivalent to 10s of casting speed during membrane fabrications managed to remove about 68% of ammonia-nitrogen, in which its separation performance is the most favourable by means of highest flux and rejection ability towards unwanted solutes. Besides, from the research findings, nano-membrane technology is a potential candidate for the treatment of aquaculture wastewater.
    Matched MeSH terms: Microscopy, Electron, Scanning
  9. Removal of disperse dye from aqueous solution using waste-derived activated carbon: optimization study
    Ahmad AA, Hameed BH, Ahmad AL
    J Hazard Mater, 2009 Oct 30;170(2-3):612-9.
    PMID: 19515487 DOI: 10.1016/j.jhazmat.2009.05.021
    The purpose of this work is to obtain optimal preparation conditions for activated carbons prepared from rattan sawdust (RSAC) for removal of disperse dye from aqueous solution. The RSAC was prepared by chemical activation with phosphoric acid using response surface methodology (RSM). RSM based on a three-variable central composite design was used to determine the effect of activation temperature (400-600 degrees C), activation time (1-3h) and H(3)PO(4):precursor (wt%) impregnation ratio (3:1-6:1) on C.I. Disperse Orange 30 (DO30) percentage removal and activated carbon yield were investigated. Based on the central composite design, quadratic model was developed to correlate the preparation variables to the two responses. The most influential factor on each experimental design responses was identified from the analysis of variance (ANOVA). The optimum conditions for preparation of RSAC, which were based on response surface and contour plots, were found as follows: temperature of 470 degrees C, activation time of 2h and 14min and chemical impregnation ratio of 4.45.
    Matched MeSH terms: Microscopy, Electron, Scanning
  10. Growth arrest and induction of apoptotic and non-apoptotic programmed cell death by, Physalis minima L. chloroform extract in human ovarian carcinoma Caov-3 cells
    Ooi KL, Muhammad TS, Sulaiman SF
    J Ethnopharmacol, 2010 Mar 2;128(1):92-9.
    PMID: 20045455 DOI: 10.1016/j.jep.2009.12.032
    The decoction of the whole plant of Physalis minima L. is traditionally consumed to treat cancer. Its anticancer property has been previously verified (using in vitro cytotoxicity assays) against NCI-H23 lung, CORL23 lung and MCF7 breast cancer cell lines but the mechanism underlying the anticancer potency towards ovarian carcinoma cells remain unclear.
    Matched MeSH terms: Microscopy, Electron, Scanning
  11. Adsorption isotherm and kinetic modeling of 2,4-D pesticide on activated carbon derived from date stones
    Hameed BH, Salman JM, Ahmad AL
    J Hazard Mater, 2009 Apr 15;163(1):121-6.
    PMID: 18667269 DOI: 10.1016/j.jhazmat.2008.06.069
    In this work, the adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) on activated carbon derived from date stones (DSAC) was studied with respect to pH and initial 2,4-D concentration. The experimental data were analyzed by the Freundlich isotherm, the Langmuir isotherm, and the Temkin isotherm. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 238.10 mg/g. Pseudo-first and pseudo-second-order kinetics models were tested with the experimental data, and pseudo-first-order kinetics was the best for the adsorption of 2,4-D by DSAC with coefficients of correlation R(2)>or=0.986 for all initial 2,4-D concentrations studied. The results indicated that the DSAC is very effective for the adsorption of 2,4-D from aqueous solutions.
    Matched MeSH terms: Microscopy, Electron, Scanning
  12. Evaluation of various additives on the preparation of rice husk ash (RHA)/CaO-based sorbent for flue gas desulfurization (FGD) at low temperature
    Dahlan I, Lee KT, Kamaruddin AH, Mohamed AR
    J Hazard Mater, 2009 Jan 15;161(1):570-4.
    PMID: 18462871 DOI: 10.1016/j.jhazmat.2008.03.097
    This paper examines the effectiveness of 10 additives toward improving SO2 sorption capacities (SSC) of rice husk ash (RHA)/lime (CaO) sorbent. The additives examined are NaOH, CaCl2, LiCl, NaHCO3, NaBr, BaCl2, KOH, K2HPO4, FeCl3 and MgCl2. Most of the additives tested increased the SSC of RHA/CaO sorbent, whereby NaOH gave highest SSC (30mg SO2/g sorbent) at optimum concentration (0.25mol/l) compared to other additives examined. The SSC of RHA/CaO sorbent prepared with NaOH addition was also increases from 17.2 to 39.5mg SO2/g sorbent as the water vapor increases from 0% RH to 80% RH. This is probably due to the fact that most of additives tested act as deliquescent material, and its existence increases the amount of water collected on the surface of the sorbent, which played an important role in the reaction between the dry-type sorbent and SO2. Although most of the additives were shown to have positive effect on the SSC of the RHA/CaO sorbent, some were found to have negative or insignificant effect. Thus, this study demonstrates that proper selection of additives can improve the SSC of RHA/CaO sorbent significantly.
    Matched MeSH terms: Microscopy, Electron, Scanning
  13. In vivo encystation of Blastocystis hominis
    Suresh K, Venilla GD, Tan TC, Rohela M
    Parasitol Res, 2009 Jun;104(6):1373-80.
    PMID: 19238443 DOI: 10.1007/s00436-009-1340-1
    Blastocystis from infected stools of a person who showed chronic symptoms of abdominal discomfort and diarrhea were examined over a 6-month period, using transmission electron microscopy, for the ultrastructural changes from vacuolar to cystic stage. The study confirms the irregular shedding phenomenon of the organism previously reported, and for the first time, records sequential changes in encystation in stools collected over a time period. The study also confirms the existence of a precystic stage which has an immature cell wall consisting of a layer of a homogenous electron-dense mass surrounding the cell which acts as a intermediatory stage between the vacuolar and cystic stage.
    Matched MeSH terms: Microscopy, Electron, Transmission
  14. Fulltext Susceptibility of selected tooth-coloured dental materials to damage by common erosive acids
    Wan Bakar W, McIntyre J
    Aust Dent J, 2008 Sep;53(3):226-34.
    PMID: 18782366 DOI: 10.1111/j.1834-7819.2008.00053.x
    Erosive substances such as gastric acids, lemon juice and even the less erosive cola drinks have been extensively investigated for their destructive effects on enamel. However, their effects on the tooth-coloured restoratives has not been widely analysed. The objective of this study was to assess their effects on the more commonly used glass containing restorative materials in vitro.
    Matched MeSH terms: Microscopy, Electron, Scanning
  15. Fulltext Role of electron microscopy in Nipah virus outbreak investigation and control
    Chua KB, Wong EM, Cropp BC, Hyatt AD
    Med J Malaysia, 2007 Jun;62(2):139-42.
    PMID: 18705447 MyJurnal
    In 1998, a novel paramyxovirus (order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Henipavirus) emerged in peninsular Malaysia causing fatal encephalitis in humans and severe respiratory illness with encephalitis in pigs. The virus was successfully isolated in cultured mammalian cells. Transmission electron microscopy of infected tissue culture cells played a crucial role in the early preliminary identification of the causative agent of the outbreak. This in turn was pivotal to determine the correct direction of control measures that subsequently brought the epidemic under control. In light of this investigation, and indeed identification of infectious agents associated with other disease episodes, electron microscopy will remain an important frontline method for rapid diagnostic virology and investigation of any future outbreak of new and unusual cases of illness suspected of an infectious aetiology.
    Matched MeSH terms: Microscopy, Electron
  16. A novel agricultural waste adsorbent for the removal of cationic dye from aqueous solutions
    Hameed BH, Krishni RR, Sata SA
    J Hazard Mater, 2009 Feb 15;162(1):305-11.
    PMID: 18573607 DOI: 10.1016/j.jhazmat.2008.05.036
    In this paper, pineapple stem (PS) waste, an agricultural waste available in large quantity in Malaysia, was utilized as low-cost adsorbent to remove basic dye (methylene blue, MB) from aqueous solution by adsorption. Batch mode experiments were conducted at 30 degrees C to study the effects of initial concentration of methylene blue, contact time and pH on dye adsorption. Equilibrium adsorption isotherms and kinetic were investigated. The experimental data were analyzed by the Langmuir and Freundlich models and the isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 119.05mg/g. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order and pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model. The PS was found to be very effective adsorbent for MB adsorption.
    Matched MeSH terms: Microscopy, Electron, Scanning
  17. Adsorption of basic dye on high-surface-area activated carbon prepared from coconut husk: equilibrium, kinetic and thermodynamic studies
    Tan IA, Ahmad AL, Hameed BH
    J Hazard Mater, 2008 Jun 15;154(1-3):337-46.
    PMID: 18035483
    Adsorption isotherm and kinetics of methylene blue on activated carbon prepared from coconut husk were determined from batch tests. The effects of contact time (1-30 h), initial dye concentration (50-500 mg/l) and solution temperature (30-50 degrees C) were investigated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The equilibrium data were best represented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 434.78 mg/g. The kinetic data were fitted to pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and was found to follow closely the pseudo-second-order kinetic model. Thermodynamic parameters such as standard enthalpy (DeltaH degrees), standard entropy (DeltaS degrees) and standard free energy (DeltaG degrees) were evaluated. The adsorption interaction was found to be exothermic in nature. Coconut husk-based activated carbon was shown to be a promising adsorbent for removal of methylene blue from aqueous solutions.
    Matched MeSH terms: Microscopy, Electron, Scanning
  18. Preparation of activated carbon from coconut husk: optimization study on removal of 2,4,6-trichlorophenol using response surface methodology
    Tan IA, Ahmad AL, Hameed BH
    J Hazard Mater, 2008 May 1;153(1-2):709-17.
    PMID: 17935879
    Activated carbon was prepared from coconut husk using physicochemical activation method which consisted of potassium hydroxide (KOH) treatment and carbon dioxide (CO(2)) gasification. The effects of three preparation variables (CO(2) activation temperature, CO(2) activation time and KOH:char impregnation ratio) on the 2,4,6-trichlorophenol (2,4,6-TCP) uptake and activated carbon yield were investigated. Based on the central composite design, two quadratic models were developed to correlate the preparation variables to the two responses. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The activated carbon preparation conditions were optimized by maximizing both the 2,4,6-TCP uptake and activated carbon yield. The predicted 2,4,6-TCP uptake and carbon yield from the models agreed satisfactorily with the experimental values. The optimum conditions for preparing activated carbon from coconut husk for adsorption of 2,4,6-TCP were found as follow: CO(2) activation temperature of 750 degrees C, CO(2) activation time of 2.29 h and KOH:char impregnation ratio of 2.91, which resulted in 191.73 mg/g of 2,4,6-TCP uptake and 20.16 % of activated carbon yield.
    Matched MeSH terms: Microscopy, Electron, Scanning
  19. Reconstruction of living bilayer human skin equivalent utilizing human fibrin as a scaffold
    Mazlyzam AL, Aminuddin BS, Fuzina NH, Norhayati MM, Fauziah O, Isa MR, et al.
    Burns, 2007 May;33(3):355-63.
    PMID: 17321690
    Our aim of this study was to develop a new methodology for constructing a bilayer human skin equivalent to create a more clinical compliance skin graft composite for the treatment of various skin defects. We utilized human plasma derived fibrin as the scaffold for the development of a living bilayer human skin equivalent: fibrin-fibroblast and fibrin-keratinocyte (B-FF/FK SE). Skin cells from six consented patients were culture-expanded to passage 1. For B-FF/FK SE formation, human fibroblasts were embedded in human fibrin matrix and subsequently another layer of human keratinocytes in human fibrin matrix was stacked on top. The B-FF/FK SE was then transplanted to athymic mice model for 4 weeks to evaluate its regeneration and clinical performance. The in vivo B-FF/FK SE has similar properties as native human skin by histological analysis and expression of basal Keratin 14 gene in the epidermal layer and Collagen type I gene in the dermal layer. Electron microscopy analysis of in vivo B-FF/FK SE showed well-formed and continuous epidermal-dermal junction. We have successfully developed a technique to engineer living bilayer human skin equivalent using human fibrin matrix. The utilization of culture-expanded human skin cells and fibrin matrix from human blood will allow a fully autologous human skin equivalent construction.
    Matched MeSH terms: Microscopy, Electron
  20. The oil-absorbing property of polyhydroxyalkanoate films and its practical application: a refreshing new outlook for an old degrading material
    Sudesh K, Loo CY, Goh LK, Iwata T, Maeda M
    Macromol Biosci, 2007 Nov 12;7(11):1199-205.
    PMID: 17703476
    Polyhydroxyalkanoates (PHAs) have attracted the attention of academia and industry because of their plastic-like properties and biodegradability. However, practical applications as a commodity material have not materialized because of their high production cost and unsatisfactory mechanical properties. PHAs are also believed to have high-value applications as an absorbable biomaterial for tissue engineering and drug-delivery devices because of their biocompatibility. However, research in these areas is still in its very early stages. The main problem faced by proponents of PHAs is the lack of a niche area where PHAs will be the most desired material in terms of its function during use rather than because of its eco-friendly virtues after use. Here, we report on the oil-absorbing property of PHA films and its potential applications. By comparing with some of the existing commercial products, the potential application of PHAs as cosmetic oil-blotting films is revealed for the first time. Besides having the ability to rapidly absorb and retain oil, PHA films also have a natural oil-indicator property, showing obvious changes in opacity following oil absorption. Surface analysis revealed that the surface structures such as porosity and smoothness exert great influence on the rapid oil-absorption properties of the PHA films. These newly discovered properties could be exploited to create a niche area for the practical applications of PHAs.
    Matched MeSH terms: Microscopy, Electron, Scanning
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