Displaying publications 261 - 280 of 384 in total

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  1. Surface modification via wet chemical etching of single-crystalline silicon for photovoltaic application
    Reshak AH, Shahimin MM, Shaari S, Johan N
    Prog Biophys Mol Biol, 2013 Nov;113(2):327-32.
    PMID: 24139943 DOI: 10.1016/j.pbiomolbio.2013.10.002
    The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO3:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells.
    Matched MeSH terms: Surface Properties
  2. Fulltext A facile thermal-treatment route to synthesize ZnO nanosheets and effect of calcination temperature
    Al-Hada NM, Saion EB, Shaari AH, Kamarudin MA, Flaifel MH, Ahmad SH, et al.
    PLoS One, 2014;9(8):e103134.
    PMID: 25093752 DOI: 10.1371/journal.pone.0103134
    A facile thermal-treatment route was successfully used to synthesize ZnO nanosheets. Morphological, structural, and optical properties of obtained nanoparticles at different calcination temperatures were studied using various techniques. The FTIR, XRD, EDX, SEM and TEM images confirmed the formation of ZnO nanosheets through calcination in the temperature between 500 to 650 °C. The SEM images showed a morphological structure of ZnO nanosheets, which inclined to crumble at higher calcination temperatures. The XRD and FTIR spectra revealed that the samples were amorphous at 30 °C but transformed into a crystalline structure during calcination process. The average particle size and degree of crystallinity increased with increasing calcination temperature. The estimated average particle sizes from TEM images were about 23 and 38 nm for the lowest and highest calcination temperature i.e. 500 and 650 °C, respectively. The optical properties were determined by UV-Vis reflection spectrophotometer and showed a decrease in the band gap with increasing calcination temperature.
    Matched MeSH terms: Surface Properties
  3. Fulltext Molecular dynamics simulation of palmitate ester self-assembly with diclofenac
    Abedi Karjiban R, Basri M, Abdul Rahman MB, Salleh AB
    Int J Mol Sci, 2012;13(8):9572-9583.
    PMID: 22949816 DOI: 10.3390/ijms13089572
    Palm oil-based esters (POEs) are unsaturated and non-ionic esters with a great potential to act as chemical penetration enhancers and drug carriers for transdermal drug nano-delivery. A ratio of palmitate ester and nonionic Tween80 with and without diclofenac acid was chosen from an experimentally determined phase diagram. Molecular dynamics simulations were performed for selected compositions over a period of 15 ns. Both micelles showed a prolate-like shape, while adding the drug produced a more compact micellar structure. Our results proposed that the drug could behave as a co-surfactant in our simulated model.
    Matched MeSH terms: Surface Properties
  4. Fulltext A Novel Coated Suture Displays Antimicrobial Activity Without Compromising Structural Properties
    Daood U, Ilyas MS, Ashraf M, Akbar M, Asif A, Khan AS, et al.
    J Oral Maxillofac Surg, 2024 Sep;82(9):1147-1162.
    PMID: 38830601 DOI: 10.1016/j.joms.2024.05.004
    BACKGROUND: Treated or coated sutures promise to prevent contamination of wounds.

    PURPOSE: The purpose of the study was to coat surgical sutures with a new quaternary ammonium silane (QAS) antimicrobial compound at two different application temperatures and then to evaluate the resulting structural, physical, mechanical, and biological properties.

    STUDY DESIGN, SETTING, SAMPLE: In vitro and in vivo studies were conducted using male albino Wistar rats approved by the Joint Ethical Committee of IMU and Postgraduate Medical Institute, Lahore. Only suture samples, coated uniformly with verified presence of the compound and of adequate length were used. Samples which were not coated uniformly and with inadequate length or damaged were excluded.

    PREDICTOR VARIABLE: Predictor variables were sutures with and without QAS coatings and different temperatures. Sutures were coated with QAS at 0.5 and 1.0% wt/vol using the dip coating technique and sutures with and without QAS coating were tested at 25 and 40 °C temperatures.

    MAIN OUTCOME VARIABLE(S): Outcome variables of structural and physico-mechanical properties of QAS-coated and non-coated sutures were measured using Fourier transform infrared spectroscopy (for structural changes), confocal laser and scanning electron (for diameter changes), and tensile strength/modulus (for mechanical testing). Biologic outcome variables were tested (bacterial viability); macrophage cultures from Wistar rats were tested (M1/M2 polarization detecting IL-6 and IL-10). Macrophage cells were analyzed with CD80+ (M1) and CD163+ (M2). Chemotaxis index was calculated as a ratio of quantitative fluorescence of cells.

    COVARIATES: Not applicable.

    ANALYSES: Ordinal data among groups were compared using the Wilcoxon Mann-Whitney U test along with the comparison of histological analysis using the Wilcoxon Sign-rank test (P 

    Matched MeSH terms: Surface Properties
  5. Fulltext Cellulose nanocrystals/ZnO as a bifunctional reinforcing nanocomposite for poly(vinyl alcohol)/chitosan blend films: fabrication, characterization and properties
    Azizi S, Ahmad MB, Ibrahim NA, Hussein MZ, Namvar F
    Int J Mol Sci, 2014 Jun 18;15(6):11040-53.
    PMID: 24945313 DOI: 10.3390/ijms150611040
    In this study, cellulose nanocrystals/zinc oxide (CNCs/ZnO) nanocomposites were dispersed as bifunctional nano-sized fillers into poly(vinyl alcohol) (PVA) and chitosan (Cs) blend by a solvent casting method to prepare PVA/Cs/CNCs/ZnO bio-nanocomposites films. The morphology, thermal, mechanical and UV-vis absorption properties, as well antimicrobial effects of the bio-nanocomposite films were investigated. It demonstrated that CNCs/ZnO were compatible with PVA/Cs and dispersed homogeneously in the polymer blend matrix. CNCs/ZnO improved tensile strength and modulus of PVA/Cs significantly. Tensile strength and modulus of bio-nanocomposite films increased from 55.0 to 153.2 MPa and from 395 to 932 MPa, respectively with increasing nano-sized filler amount from 0 to 5.0 wt %. The thermal stability of PVA/Cs was also enhanced at 1.0 wt % CNCs/ZnO loading. UV light can be efficiently absorbed by incorporating ZnO nanoparticles into a PVA/Cs matrix, signifying that these bio-nanocomposite films show good UV-shielding effects. Moreover, the biocomposites films showed antibacterial activity toward the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The improved physical properties obtained by incorporating CNCs/ZnO can be useful in variety uses.
    Matched MeSH terms: Surface Properties
  6. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application
    Baradaran S, Moghaddam E, Nasiri-Tabrizi B, Basirun WJ, Mehrali M, Sookhakian M, et al.
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:656-668.
    PMID: 25686995 DOI: 10.1016/j.msec.2015.01.050
    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3wt.% and 6wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900°C for 1h. The GNP (0.5-2wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150°C and 160MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5wt.% was the optimum value.
    Matched MeSH terms: Surface Properties
  7. EPA-coated titanium implants promote osteoconduction in white New Zealand rabbits
    Mustafa A, Lung CY, Mustafa NS, Mustafa BA, Kashmoola MA, Zwahlen RA, et al.
    Clin Oral Implants Res, 2016 Mar;27(3):303-9.
    PMID: 25393376 DOI: 10.1111/clr.12525
    OBJECTIVES: To investigate the effect of eicosapentaenoic acid (EPA)-coated Ti implants on osteoconduction in white New Zealand rabbit mandibles.

    MATERIAL AND METHODS: Sandblasted and cleansed planar titanium specimens with a size of 5 × 5 × 1 mm were coated on one side with 0.25 vol% eicosapentaenoic acid (EPA). The other side of the specimens was kept highly polished (the control side). These specimens were inserted in rabbit mandibles. Twelve rabbits were randomly assigned into three study groups (n = 4). The rabbits were sacrificed at 4, 8, and 12 weeks. The harvested specimens with the implants were assessed for new bone formation on both sides of the implant using CBCT, conventional radiographs, and the biaxial pullout test. The results were statistically analyzed by a nonparametric Kruskal-Wallis test and Friedman's test as multiple comparisons and by Brunner-Langer nonparametric mixed model approach (R Software).

    RESULTS: A significant osteoconductive bone formation was found on the EPA-coated Ti implant surface (P < 0.05) at 8 weeks when compared to the polished surface (control). Biaxial pullout test results showed a significant difference (P < 0.05) after 8 and 12 weeks with a maximum force of 243.8 N, compared to 143.25 N after 4 week.

    CONCLUSION: EPA implant coating promoted osteoconduction on the Ti implant surfaces, enhancing the anchorage of the implant to the surrounding bone in white New Zealand rabbits.

    Matched MeSH terms: Surface Properties
  8. Fulltext Measurements of the stiffness and thickness of the pavement asphalt layer using the enhanced resonance search method
    Zakaria NM, Yusoff NI, Hardwiyono S, Nayan KA, El-Shafie A
    ScientificWorldJournal, 2014;2014:594797.
    PMID: 25276854 DOI: 10.1155/2014/594797
    Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard.
    Matched MeSH terms: Surface Properties
  9. Improved cellular response of chemically crosslinked collagen incorporated hydroxyethyl cellulose/poly(vinyl) alcohol nanofibers scaffold
    Zulkifli FH, Jahir Hussain FS, Abdull Rasad MS, Mohd Yusoff M
    J Biomater Appl, 2015 Feb;29(7):1014-27.
    PMID: 25186524 DOI: 10.1177/0885328214549818
    The aim of this research is to develop biocompatible nanofibrous mats using hydroxyethyl cellulose with improved cellular adhesion profiles and stability and use these fibrous mats as potential scaffold for skin tissue engineering. Glutaraldehyde was used to treat the scaffolds water insoluble as well as improve their biostability for possible use in biomedical applications. Electrospinning of hydroxyethyl cellulose (5 wt%) with poly(vinyl alcohol) (15 wt%) incorporated with and without collagen was blended at (1:1:1) and (1:1) ratios, respectively, and was evaluated for optimal criteria as tissue engineering scaffolds. The nanofibrous mats were crosslinked and characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Scanning electron microscope images showed that the mean diameters of blend nanofibers were gradually increased after chemically crosslinking with glutaraldehyde. Fourier transform infrared spectroscopy was carried out to understand chemical interactions in the presence of aldehyde groups. Thermal characterization results showed that the stability of hydroxyethyl cellulose/poly(vinyl alcohol) and hydroxyethyl cellulose/poly(vinyl alcohol)/collagen nanofibers was increased with glutaraldehyde treatment. Studies on cell-scaffolds interaction were carried out by culturing human fibroblast (hFOB) cells on the nanofibers by assessing the growth, proliferation, and morphologies of cells. The scanning electron microscope results show that better cell proliferation and attachment appeared on hydroxyethyl cellulose/poly(vinyl alcohol)/collagen substrates after 7 days of culturing, thus, promoting the potential of electrospun scaffolds as a promising candidate for tissue engineering applications.
    Matched MeSH terms: Surface Properties
  10. Synthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/chitosan/silver nanocomposite material with enhanced antimicrobial activity
    Rennukka M, Sipaut CS, Amirul AA
    Biotechnol Prog, 2014 Nov-Dec;30(6):1469-79.
    PMID: 25181613 DOI: 10.1002/btpr.1986
    This work aims to shed light in the fabrication of poly(3-hydroxybutyrate-co-44%-4-hydroxybutyrate)[P(3HB-co-44%4HB)]/chitosan-based silver nanocomposite material using different contents of silver nanoparticle (SNP); 1-9 wt%. Two approaches were applied in the fabrication; namely solvent casting and chemical crosslinking via glutaraldehyde (GA). A detailed characterization was conducted in order to yield information regarding the nanocomposite material. X-ray diffraction analysis exhibited the nature of the three components that exist in the nanocomposite films: P(3HB-co-4HB), chitosan, and SNP. In term of mechanical properties, tensile strength, and elongation at break were significantly improved up to 125% and 22%, respectively with the impregnation of the SNP. The melting temperature of the nanocomposite materials was increased whereas their thermal stability was slightly changed. Scanning electron microscopy images revealed that incorporation of 9 wt% of SNP caused agglomeration but the surface roughness of the material was significantly improved with the loading. Staphylococcus aureus and Escherichia coli were completely inhibited by the nanocomposite films with 7 and 9 wt% of SNP, respectively. On the other hand, degradation of the nanocomposite materials outweighed the degradation of the pure copolymer. These bioactive and biodegradable materials stand a good chance to serve the vast need of biomedical applications namely management and care of wound as wound dressing.
    Matched MeSH terms: Surface Properties
  11. The role of particle-to-cell interactions in dictating nanoparticle aided magnetophoretic separation of microalgal cells
    Toh PY, Ng BW, Ahmad AL, Chieh DC, Lim J
    Nanoscale, 2014 Nov 7;6(21):12838-48.
    PMID: 25227473 DOI: 10.1039/c4nr03121k
    Successful application of a magnetophoretic separation technique for harvesting biological cells often relies on the need to tag the cells with magnetic nanoparticles. This study investigates the underlying principle behind the attachment of iron oxide nanoparticles (IONPs) onto microalgal cells, Chlorella sp. and Nannochloropsis sp., in both freshwater and seawater, by taking into account the contributions of various colloidal forces involved. The complex interplay between van der Waals (vdW), electrostatic (ES) and Lewis acid-base interactions (AB) in dictating IONP attachment was studied under the framework of extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) analysis. Our results showed that ES interaction plays an important role in determining the net interaction between the Chlorella sp. cells and IONPs in freshwater, while the AB and vdW interactions play a more dominant role in dictating the net particle-to-cell interaction in high ionic strength media (≥100 mM NaCl), such as seawater. XDLVO predicted effective attachment between cells and surface functionalized IONPs (SF-IONPs) with an estimated secondary minimum of -3.12 kT in freshwater. This prediction is in accordance with the experimental observation in which 98.89% of cells can be magnetophoretically separated from freshwater with SF-IONPs. We have observed successful magnetophoretic separation of microalgal cells from freshwater and/or seawater for all the cases as long as XDLVO analysis predicts particle attachment. For both the conditions, no pH adjustment is required for particle-to-cell attachment.
    Matched MeSH terms: Surface Properties
  12. Effect of experimental silane-based primers with various contents of 2-hydroxyethyl methacrylate on the bond strength of orthodontic adhesives
    Mustafa AA, Matinlinna JP, Razak AA, Hussin AS
    J Investig Clin Dent, 2015 Aug;6(3):161-9.
    PMID: 24415731 DOI: 10.1111/jicd.12083
    AIM: To evaluate in vitro the effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) in experimental silane-based primers on shear bond strength of orthodontic adhesives.

    METHODS: Different volume percentages of HEMA were tested in four experimental silane-based primer solutions (additions of HEMA: 0, 5.0 vol%, 25.0 vol% and 50.0 vol%). An experimental silane blend (primer) of 1.0 vol% 3-isocyanatopropyltrimethoxysilane (ICMS) + 0.5% bis-1,2-(triethoxysilyl) ethane (BTSE) was prepared and used. The experimental primers together with the control group were applied onto acid-etched premolars for attachment of orthodontic brackets. After artificial aging by thermocycling the shear-bond strength was measured. The fractured surfaces of all specimens were examined under scanning electron microscopy (SEM) to evaluate the failure mode on the enamel surface.

    RESULTS: The experimental primers showed the highest shear-bond strength of 21.15 MPa (SD ± 2.70 MPa) and with 25 vol% showed a highly significant increase (P < 0.05) in bond strength. The SEM images showed full penetration of adhesive agents when using silane-based primers. In addition, the SEM images suggested that the predominant failure type was not necessarily the same as for the failure propagation.

    CONCLUSIONS: This preliminary study suggested that nonacidic silane-based primers with HEMA addition might be an alternative to for use as adhesion promoting primers.

    Matched MeSH terms: Surface Properties
  13. Improvement of early cell adhesion on Thai silk fibroin surface by low energy plasma
    Amornsudthiwat P, Mongkolnavin R, Kanokpanont S, Panpranot J, Wong CS, Damrongsakkul S
    Colloids Surf B Biointerfaces, 2013 Nov 1;111:579-86.
    PMID: 23893032 DOI: 10.1016/j.colsurfb.2013.07.009
    Low energy plasma has been introduced to treat the surface of Thai silk fibroin which should be enhanced for cell adhesion due to its native hydrophobic surface. Plasma surface treatment could introduce desirable hydrophilic functionalities on the surface without using any chemicals. In this work, nitrogen glow discharge plasma was generated by a low energy AC50Hz power supply system. The plasma operating conditions were optimized to reach the highest nitrogen active species by using optical emission spectroscopy. X-ray photoelectron spectroscopy (XPS) revealed that amine, hydroxyl, ether, and carboxyl groups were induced on Thai silk fibroin surface after plasma treatment. The results on Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy confirmed that the plasma treated effects were only on the outermost layer since there was no change in the bulk chemistry. The surface topography was insignificantly changed from the detection with atomic force microscopy (AFM). The plasma-treated effects were the improved surface wettability and cell adhesion. After a 90-s treatment, the water contact angle was at 20°, while the untreated surface was at 70°. The early cell adhesion of L929 mouse fibroblast was accelerated. L929 cells only took 3h to reach 100% cell adhesion on 90 s N2 plasma-treated surface, while there was less than 50% cell adhesion on the untreated Thai silk fibroin surface after 6h of culture. The cell adhesion results were in agreement with the cytoskeleton development. L929 F-actin was more evident on 90 s N2 plasma-treated surface than others. It could be concluded that a lower energy AC50Hz plasma system enhanced early L929 mouse fibroblast adhesion on Thai silk fibroin surface without any significant change in surface topography and bulk chemistry.
    Matched MeSH terms: Surface Properties
  14. Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface
    Saidin S, Chevallier P, Abdul Kadir MR, Hermawan H, Mantovani D
    Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4715-24.
    PMID: 24094179 DOI: 10.1016/j.msec.2013.07.026
    Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316 L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24 h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3 days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24 h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7 days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application.
    Matched MeSH terms: Surface Properties
  15. Aluminium and radiation cross-linked carboxymethyl sago pulp beads for colon targeted delivery
    Thenapakiam S, Kumar DG, Pushpamalar J, Saravanan M
    Carbohydr Polym, 2013 Apr 15;94(1):356-63.
    PMID: 23544549 DOI: 10.1016/j.carbpol.2013.01.004
    The carboxymethyl sago pulp (CMSP) with a degree of substitution of 0.4% was synthesized from sago waste. The CMSP beads with an average diameter of 3.1-4.8 mm were formed by aluminium chloride gelation as well as further cross-linked by irradiation. To evaluate colon targeted release, a model drug, 5-aminosalicylic acid (5-ASA) was encapsulated in CMSP beads. Fourier-transform infrared spectroscopy and X-ray diffraction studies indicated intact and amorphous nature of entrapped drug. A pH dependent drug release was observed, and about 90% of the drug was released only at pH 7.4 over 9 h. Irradiated beads were resisted the drug release in an acidic environment at a higher extent than non-irradiated beads. The drug release from 6% (w/w) of 5-ASA loaded bead followed zero order, whereas, 15 and 22% loaded beads followed first order. The release exponent n value suggests non-fickian transport of 5-ASA from the beads.
    Matched MeSH terms: Surface Properties
  16. Effects of different implant-abutment connections on micromotion and stress distribution: prediction of microgap formation
    Saidin S, Abdul Kadir MR, Sulaiman E, Abu Kasim NH
    J Dent, 2012 Jun;40(6):467-74.
    PMID: 22366313 DOI: 10.1016/j.jdent.2012.02.009
    The aim of this study was to analyse micromotion and stress distribution at the connections of implants and four types of abutments: internal hexagonal, internal octagonal, internal conical and trilobe.
    Matched MeSH terms: Surface Properties
  17. Fabrication and mechanical properties of Al2O3/SiC/ZrO2 functionally graded material by electrophoretic deposition
    Askari E, Mehrali M, Metselaar IH, Kadri NA, Rahman MM
    J Mech Behav Biomed Mater, 2012 Aug;12:144-50.
    PMID: 22732480 DOI: 10.1016/j.jmbbm.2012.02.029
    This study describes the synthesis of Al(2)O(3)/SiC/ZrO(2) functionally graded material (FGM) in bio-implants (artificial joints) by electrophoretic deposition (EPD). A suitable suspension that was based on 2-butanone was applied for the EPD of Al(2)O(3)/SiC/ZrO(2), and a pressureless sintering process was applied as a presintering. Hot isostatic pressing (HIP) was used to densify the deposit, with beneficial mechanical properties after 2 h at 1800 °C in Ar atmosphere. The maximum hardness in the outer layer (90 vol.% Al(2)O(3)+10 vol.% SiC) and maximum fracture toughness in the core layer (75 vol.% Al(2)O(3)+10 vol.% SiC + 15 vol.% ZrO(2)) composite were 20.8±0.3 GPa and 8±0.1 MPa m(1/2), respectively. The results, when compared with results from Al(2)O(3)/ZrO(2) FGM, showed that SiC increased the compressive stresses in the outer layers, while the inner layers were under a residual tensile stress.
    Matched MeSH terms: Surface Properties
  18. Fulltext In vitro inhibition of histamine release behavior of cetirizine intercalated into Zn/Al- and Mg/Al-layered double hydroxides
    Hussein-Al-Ali SH, Al-Qubaisi M, Hussein MZ, Ismail M, Zainal Z, Hakim MN
    Int J Mol Sci, 2012;13(5):5899-916.
    PMID: 22754339 DOI: 10.3390/ijms13055899
    The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs) and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR) study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively.
    Matched MeSH terms: Surface Properties
  19. Fulltext The effect of bur preparation on the surface roughness and reline bond strength of urethane dimethacrylate denture base resin
    Baig MR, Ariff FT, Yunus N
    Indian J Dent Res, 2011 Mar-Apr;22(2):210-2.
    PMID: 21891887 DOI: 10.4103/0970-9290.84288
    BACKGROUND: The clinical success of relining depends on the ability of reline resin to bond to denture base. Surface preparations may influence reline bond strength of urethane-based dimethacrylate denture base resin.
    AIM: To investigate the effect of bur preparation on the surface roughness (R a ) of eclipse denture base resin and its shear bond strength (SBS) to an intra-oral self-curing reline material. The mode of reline bonding failure was also examined.
    MATERIALS AND METHODS: Twenty-four cylindrical Eclipse™ specimens were prepared and separated into three groups of eight specimens each. Two groups were subjected to mechanical preparation using standard and fine tungsten carbide (TC) burs and the third group (control) was left unprepared. The R a of all specimens was measured using a contact stylus profilometer. Subsequently, relining was done on the prepared surface and SBS testing was carried out a day later using a universal testing machine.
    RESULTS: One-way ANOVA revealed significant differences (P<0.05) in R a and SBS values for all the groups. Post-hoc Tukey's HSD test showed significant differences (P<0.05) between all the groups in the R a values. For SBS also there were significant differences (P<0.05), except between standard bur and control.
    CONCLUSIONS: 1) There was a statistically significant difference in the R a of Eclipse™ specimens prepared using different carbide burs (P<0.05). 2) There was a statistically significant difference in the relined SBS (P<0.05) when prepared using different burs, but the difference between the standard bur and the control group was not statistically significant.
    Matched MeSH terms: Surface Properties
  20. Wavelet neural networks applied to pulping of oil palm fronds
    Zainuddin Z, Wan Daud WR, Pauline O, Shafie A
    Bioresour Technol, 2011 Dec;102(23):10978-86.
    PMID: 21996481 DOI: 10.1016/j.biortech.2011.09.080
    In the organosolv pulping of the oil palm fronds, the influence of the operational variables of the pulping reactor (viz. cooking temperature and time, ethanol and NaOH concentration) on the properties of the resulting pulp (yield and kappa number) and paper sheets (tensile index and tear index) was investigated using a wavelet neural network model. The experimental results with error less than 0.0965 (in terms of MSE) were produced, and were then compared with those obtained from the response surface methodology. Performance assessment indicated that the neural network model possessed superior predictive ability than the polynomial model, since a very close agreement between the experimental and the predicted values was obtained.
    Matched MeSH terms: Surface Properties
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