Displaying publications 61 - 80 of 337 in total

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  1. Fulltext Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material
    Ibrahim S, Sabudin S, Sahid S, Marzuke MA, Hussin ZH, Kader Bashah NS, et al.
    Saudi J Biol Sci, 2016 Jan;23(1):S56-63.
    PMID: 26858566 DOI: 10.1016/j.sjbs.2015.10.024
    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material's surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si-BCP's surface roughness (164 nm) was significantly higher than BCP (88 nm), thus enhancing the adhesion and proliferation of the osteoblast.
    Matched MeSH terms: Silicon Dioxide
  2. Fulltext Aerogel Poly(butylene succinate) Biomaterial Substrate for RF and Microwave Applications
    Habib Ullah M, Mahadi WN, Latef TA
    Sci Rep, 2015;5:12868.
    PMID: 26238975 DOI: 10.1038/srep12868
    Polybutylene succinate (PBS) has become a potential candidate, similar to polypropylene (PP) and acrylonitrile butadiene styrene (ABS), for use as an organic plastic material due to its outstanding mechanical properties as well as high thermal deformation characteristics. A new composition of silica aerogel nanoparticles extracted from rice waste with PBS is proposed for use as a dielectric (εr = 4.5) substrate for microwave applications. A microstrip patch antenna was fabricated on the proposed dielectric substrate for multi-resonant ultra-wideband (UWB) applications. The performance characteristics of the proposed biomaterial-based antenna were investigated in a far-field measurement environment. The results indicate that the proposed biocompatible material-based antenna covered a bandwidth of 9.4 (2.3-11.7) GHz with stop bands from 5.5 GHz to 5.8 GHz and 7.0 GHz to 8.3 GHz. Peak gains of 9.82 dBi, 7.59 dBi, 8.0 dBi and 7.68 dBi were measured at resonant frequencies of 2.7 GHz, 4.6 GHz, 6.3 GHz and 9.5 GHz, respectively.
    Matched MeSH terms: Silicon Dioxide
  3. Fulltext Effect on Physical and Mechanical Properties of Conventional Glass Ionomer Luting Cements by Incorporation of All-Ceramic Additives: An In Vitro Study
    Saran R, Upadhya NP, Ginjupalli K, Amalan A, Rao B, Kumar S
    Int J Dent, 2020;2020:8896225.
    PMID: 33061975 DOI: 10.1155/2020/8896225
    Introduction: Glass ionomer cements (GICs) are commonly used for cementation of indirect restorations. However, one of their main drawbacks is their inferior mechanical properties.

    Aim: Compositional modification of conventional glass ionomer luting cements by incorporating two types of all-ceramic powders in varying concentrations and evaluation of their film thickness, setting time, and strength. Material & Methods. Experimental GICs were prepared by adding different concentrations of two all-ceramic powders (5%, 10, and 15% by weight) to the powder of the glass ionomer luting cements, and their setting time, film thickness, and compressive strength were determined. The Differential Scanning Calorimetry analysis was done to evaluate the kinetics of the setting reaction of the samples. The average particle size of the all-ceramic and glass ionomer powders was determined with the help of a particle size analyzer.

    Results: A significant increase in strength was observed in experimental GICs containing 10% all-ceramic powders. The experimental GICs with 5% all-ceramic powders showed no improvement in strength, whereas those containing 15% all-ceramic powders exhibited a marked decrease in strength. Setting time of all experimental GICs progressively increased with increasing concentration of all-ceramic powders. Film thickness of all experimental GICs was much higher than the recommended value for clinical application.

    Conclusion: 10% concentration of the two all-ceramic powders can be regarded as the optimal concentration for enhancing the glass ionomer luting cements' strength. There was a significant increase in the setting time at this concentration, but it was within the limit specified by ISO 9917-1:2007 specifications for powder/liquid acid-base dental cements. Reducing the particle size of the all-ceramic powders may help in decreasing the film thickness, which is an essential parameter for the clinical performance of any luting cement.

    Matched MeSH terms: Silicon Dioxide
  4. Clinical and radiographic evaluation of chloramphenicol-tetracycline-zinc eugenol oxide antibiotic paste in pulp treatment
    Jesús Luengo Fereira, Heraclio Reyes Rivas, Luz Elena Carlos Medrano, Iovanna Toscano, Minerva Anaya Alvarez
    Sains Malaysiana, 2018;47:971-976.
    This study has been carried out to evaluate the clinical and radiographic CTZ (Chloramphenicol-Tetracycline-Zinc
    Eugenol Oxide) antibiotic paste in pulpotomies of primary molars. A Quasi-experimental study in 43 primary molars
    of children aged 3 to 7 years. Pulpotomies were performed on the selected patients with the CTZ antibiotic paste. Teeth
    were restored with glass ionomer and preformed steel metal crowns. Clinical and radiographic evaluation was performed
    at 6 and 12 months. SPSS V-19 program for data analysis and chi-square test was used up to 5%. Success rates were
    observed during the evaluation periods of time. 93% (x2
    = 0.446, p>0.05) and 88.4% (x2
    = 0.431, p>0.05) of the clinical form;
    97.7% (x2
    = 0.534, p>0.05) and 93% (x2
    = 0.553, p>0.05) were radiographic, at 6 and 12 months, respectively. The CTZ antibiotic
    paste is an alternative in the treatment of pulpotomy of molars. It provides an antimicrobial effect, decreased operative time, without
    causing trauma to the pediatric patient.
    Matched MeSH terms: Silicon Dioxide
  5. Fulltext Development of Nano-SiO2 and Bentonite-Based Mortars for Corrosion Protection of Reinforcing Steel
    Karunarathne VK, Paul SC, Šavija B
    Materials (Basel), 2019 Aug 17;12(16).
    PMID: 31426501 DOI: 10.3390/ma12162622
    In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of nano-silica and bentonite addition on compressive strength of mortars at different ages was tested. Accelerated corrosion testing was used to assess the corrosion resistance of reinforced mortar specimens containing different amounts of nano-silica and bentonite. It was found that the specimens containing nano-SiO2 not only had higher compressive strength, but also showed lower steel mass loss due to corrosion compared to reference specimens. However, this was accompanied by a small reduction in workability (for a constant water to binder ratio). Mortar mixtures with 4% of nano-silica were found to have optimal performance in terms of compressive strength and corrosion resistance. Control specimens (OPC/fly ash mortars without any additives) showed low early age strength and low corrosion resistance compared to specimens containing nano-SiO2 and bentonite. In addition, samples from selected mixtures were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Finally, the influence of Ca/Si ratio of the calcium silicate hydrate (C-S-H) in different specimens on the compressive strength is discussed. In general, the study showed that the addition of nano-silica (and to a lesser extent bentonite) can result in higher strength and corrosion resistance compared to control specimens. Furthermore, the addition of nano-SiO2 can be used to offset the negative effect of fly ash on early age strength development.
    Matched MeSH terms: Silicon Dioxide
  6. Fulltext Nanoparticles in Construction Materials and Other Applications, and Implications of Nanoparticle Use
    Mohajerani A, Burnett L, Smith JV, Kurmus H, Milas J, Arulrajah A, et al.
    Materials (Basel), 2019 Sep 20;12(19).
    PMID: 31547011 DOI: 10.3390/ma12193052
    Nanoparticles are defined as ultrafine particles sized between 1 and 100 nanometres in diameter. In recent decades, there has been wide scientific research on the various uses of nanoparticles in construction, electronics, manufacturing, cosmetics, and medicine. The advantages of using nanoparticles in construction are immense, promising extraordinary physical and chemical properties for modified construction materials. Among the many different types of nanoparticles, titanium dioxide, carbon nanotubes, silica, copper, clay, and aluminium oxide are the most widely used nanoparticles in the construction sector. The promise of nanoparticles as observed in construction is reflected in other adoptive industries, driving the growth in demand and production quantity at an exorbitant rate. The objective of this study was to analyse the use of nanoparticles within the construction industry to exemplify the benefits of nanoparticle applications and to address the short-term and long-term effects of nanoparticles on the environment and human health within the microcosm of industry so that the findings may be generalised. The benefits of nanoparticle utilisation are demonstrated through specific applications in common materials, particularly in normal concrete, asphalt concrete, bricks, timber, and steel. In addition, the paper addresses the potential benefits and safety barriers for using nanomaterials, with consideration given to key areas of knowledge associated with exposure to nanoparticles that may have implications for health and environmental safety. The field of nanotechnology is considered rather young compared to established industries, thus limiting the time for research and risk analysis. Nevertheless, it is pertinent that research and regulation precede the widespread adoption of potentially harmful particles to mitigate undue risk.
    Matched MeSH terms: Silicon Dioxide
  7. Nano-silica embedded polydimethylsiloxane on interdigitated sensor as adhesive polymer for detecting lung cancer mutation
    Abulaiti A, Salai A, Sun X, Yibulayin W, Gao Y, Gopinath SCB, et al.
    Biotechnol Appl Biochem, 2021 Feb 12.
    PMID: 33576539 DOI: 10.1002/bab.2122
    Non-small cell lung cancer (NSCLC) incited by epidermal growth factor receptor (EGFR) mutation makes up ∼85% of lung cancer diagnosed and death cases worldwide. The presented study introduced an alternative approach in detecting EGFR mutation using nano-silica integrated with polydimethylsiloxane (PDMS) polymer on interdigitated electrode (IDE) sensor. A 400 μm gap-sized aluminum IDE was modified with nano-polymer layer, which was made up of silica nanoparticles and PDMS polymer. IDE and PDMS-coated IDE (PDMS/IDE) were imaged using electron microscopes that reveals its smooth and ideal sensor morphology. The nano-silica-integrated PDMS/IDE surface was immobilized with EGFR probe and target to specify the lung cancer detection. The sensor specificity was justified through the insignificant current readouts with one-base mismatch and noncomplementary targets. The sensitivity of nano-silica-integrated PDMS/IDE was examined with mutant target spiked in human serum, where the resulting current affirms the detection of EGFR mutation. Based on the slope of the calibration curve, the sensitivity of nano-silica-integrated PDMS/IDE was 2.24E-9 A M-1 . The sensor recognizes EGFR mutation lowest at 1 aM complementary mutant target; however, the detection limit obtained based on 3σ calculation is 10 aM with regression value of 0.97.
    Matched MeSH terms: Silicon Dioxide
  8. Fulltext Role of Sintering Temperature in Production of Nepheline Ceramics-Based Geopolymer with Addition of Ultra-High Molecular Weight Polyethylene
    Ahmad R, Abdullah MMAB, Ibrahim WMW, Hussin K, Ahmad Zaidi FH, Chaiprapa J, et al.
    Materials (Basel), 2021 Feb 25;14(5).
    PMID: 33669116 DOI: 10.3390/ma14051077
    The primary motivation of developing ceramic materials using geopolymer method is to minimize the reliance on high sintering temperatures. The ultra-high molecular weight polyethylene (UHMWPE) was added as binder and reinforces the nepheline ceramics based geopolymer. The samples were sintered at 900 °C, 1000 °C, 1100 °C, and 1200 °C to elucidate the influence of sintering on the physical and microstructural properties. The results indicated that a maximum flexural strength of 92 MPa is attainable once the samples are used to be sintered at 1200 °C. It was also determined that the density, porosity, volumetric shrinkage, and water absorption of the samples also affected by the sintering due to the change of microstructure and crystallinity. The IR spectra reveal that the band at around 1400 cm-1 becomes weak, indicating that sodium carbonate decomposed and began to react with the silica and alumina released from gels to form nepheline phases. The sintering process influence in the development of the final microstructure thus improving the properties of the ceramic materials.
    Matched MeSH terms: Silicon Dioxide
  9. Fulltext Graphene Oxide-Gold Star Construct on Triangular Electrodes for Alzheimer's Disease Identification
    Chang W, Zhao J, Liu L, Xing X, Zhang C, Meng H, et al.
    J Anal Methods Chem, 2021;2021:6661799.
    PMID: 33688447 DOI: 10.1155/2021/6661799
    Nanotechnology is playing a major role in the field of medical diagnosis, in particular with the biosensor and bioimaging. It improves the performance of the desired system dramatically by displaying higher selectivity and sensitivity. Carbon nanomaterial, gold nanostructure, magnetite nanoparticle, and silica substrate are the most popular nanomaterials greatly contributed to make the affordable and effective biosensor at low-cost. This research work is introducing a new sensing strategy with graphene oxide-constructed triangular electrodes to diagnose Alzheimer's disease (AD). MicroRNA-137 (miRNA-137) was found as a suitable biomarker for AD, and the sensing method was established here to detect miRNA-137 on the complementary sequence. To enhance the immobilization of capture miRNA-137, gold nanostar (GNS) was conjugated with capture miRNA and immobilized on the GO-modified surface through an amine linker. This immobilization process enhanced the hybridization of the target and reaches the detection limit at 10 fM with the sensitivity of 1 fM on the linear curve with a regression coefficient of 0.9038. Further control sequences of miRNA-21 and single and triple base mismatched miRNA-137 did not show a significant response in current changes, indicating the specific miRNA-137 detection for diagnosing AD.
    Matched MeSH terms: Silicon Dioxide
  10. Fulltext Synthesis and characterization of rice husk biochar via hydrothermal carbonization for wastewater treatment and biofuel production
    Hossain N, Nizamuddin S, Griffin G, Selvakannan P, Mubarak NM, Mahlia TMI
    Sci Rep, 2020 Nov 02;10(1):18851.
    PMID: 33139793 DOI: 10.1038/s41598-020-75936-3
    The recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from - 30.1 to - 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0.51 delineated high breakdown of the cellulosic component, which is favorable for biofuel purpose. 13.98% SiO2 reduction in RB confirmed ash content minimization and better quality of fuel properties. Therefore, the rice husk biochar through HTC can be considered a suitable material for further application to treat wastewater and generate bioenergy.
    Matched MeSH terms: Silicon Dioxide
  11. Fulltext Preparation and Characterization of Polyphenylsulfone (PPSU) Membranes for Biogas Upgrading
    Kujawski W, Li G, Van der Bruggen B, Pedišius N, Tonkonogij J, Tonkonogovas A, et al.
    Materials (Basel), 2020 Jun 25;13(12).
    PMID: 32630434 DOI: 10.3390/ma13122847
    Asymmetric polyphenylsulfone (PPSU) membranes were fabricated by a non-solvent induced phase inversion method. Glycerin and silica nanoparticles were added into the polymer solution to investigate their effects on the material properties and gas separation performance of prepared membranes. The morphology and structure of PPSU membranes were analyzed by scanning electron microscopy (SEM), the surface roughness of the selective layer was analyzed by atomic force microscopy (AFM), and the surface free energy was calculated based on the contact angle measurements by using various solvents. The gas separation performance of PPSU membranes was estimated by measuring the permeability of CO2 and CH4. The addition of glycerin as a nonsolvent into the polymer solution changed the cross-section structure from finger-like structure into sponge-like structure due to the delayed liquid-liquid demixing process, which was confirmed by SEM analysis. The incorporation of silica nanoparticles into PPSU membranes slightly increased the hydrophilicity, which was confirmed by water contact angle results. PPSU membrane fabricated from the polymer solution containing 10 wt.% glycerin showed the best CO2/CH4 selectivity of 3.86 and the CO2 permeability of 1044.01 Barrer. Mixed matrix PPSU membrane containing 0.1 wt.% silica nanoparticles showed the CO2/CH4 selectivity of 3.16 and the CO2 permeability of 1202.77 Barrer.
    Matched MeSH terms: Silicon Dioxide
  12. Fulltext Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions
    Lau PL, Allen RW, Styring P
    Beilstein J Org Chem, 2013;9:2886-97.
    PMID: 24367454 DOI: 10.3762/bjoc.9.325
    The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR) using supercritical carbon dioxide (scCO2) as the solvent, with THF and methanol as modifiers. The catalyst was 2% palladium on silica and the base was diisopropylethylamine due to its solubility in the reaction solvent. No phosphine co-catalysts were used so the work-up procedure was simplified and the green credentials of the reaction were enhanced. The reactions were studied as a function of temperature, pressure and flow rate and in the case of the reaction with styrene compared against a standard, stirred autoclave reaction. Conversion was determined and, in the case of the reaction with styrene, the isomeric product distribution was monitored by GC. In the case of the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free catalyst, but care must be taken when selecting the reaction temperature in order to ensure the appropriate isomer distribution is achieved. Higher reaction temperatures were found to enhance formation of the branched terminal alkene isomer as opposed to the linear trans-isomer.
    Matched MeSH terms: Silicon Dioxide
  13. Friction at nanopillared polymer surfaces beyond Amontons' laws: Stick-slip amplitude coefficient (SSAC) and multiparametric nanotribological properties
    Ishak MI, Dobryden I, Martin Claesson P, Briscoe WH, Su B
    J Colloid Interface Sci, 2021 Feb 01;583:414-424.
    PMID: 33011410 DOI: 10.1016/j.jcis.2020.09.038
    Frictional and nanomechanical properties of nanostructured polymer surfaces are important to their technological and biomedical applications. In this work, poly(ethylene terephthalate) (PET) surfaces with a periodic distribution of well-defined nanopillars were fabricated through an anodization/embossing process. The apparent surface energy of the nanopillared surfaces was evaluated using the Fowkes acid-base approach, and the surface morphology was characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The normal and lateral forces between a silica microparticle and these surfaces were quantified using colloidal probe atomic force microscopy (CP-AFM). The friction-load relationship followed Amonton's first law, and the friction coefficient appeared to scale linearly with the nanopillar height. Furthermore, all the nanopillared surfaces showed pronounced frictional instabilities compared to the smooth sliding friction loop on the flat control. Performing the stick-slip amplitude coefficient (SSAC) analysis, we found a correlation between the frictional instabilities and the nanopillars density, pull-off force and work of adhesion. We have summarised the dependence of the nanotribological properties on such nanopillared surfaces on five relevant parameters, i.e. pull-off force fp, Amontons' friction coefficient μ, RMS roughness Rq, stick-slip amplitude friction coefficient SSAC, and work of adhesion between the substrate and water Wadh in a radar chart. Whilst demonstrating the complexity of the frictional behaviour of nanopillared polymer surfaces, our results show that analyses of multiparametric nanotribological properties of nanostructured surfaces should go beyond classic Amontons' laws, with the SSAC more representative of the frictional properties compared to the friction coefficient.
    Matched MeSH terms: Silicon Dioxide
  14. Effect of magnetic field on nano-magnetite composite exhibits in ion-adsorption
    Lo FF, Kow KW, Kung F, Ahamed F, Kiew PL, Yeap SP, et al.
    Sci Total Environ, 2021 Aug 01;780:146337.
    PMID: 33770606 DOI: 10.1016/j.scitotenv.2021.146337
    Nano-magnetites are widely researched for its potential as an excellent adsorbent in many applications. However, the efficiency of the nano-magnetites are hindered by their tendency to agglomerate. In this work, we dispersed and embedded the nano-magnetites in a porous silica gel matrix to form a nanocomposite to reduce the extent of agglomeration and to enhance the adsorption performance. Our experimental results showed that the removal efficiency of Cu2+ ion has improved by 46% (22.4 ± 2.2%) on the nano-magnetite-silica-gel (NMSG) nanocomposite as compared to pure nano-magnetites (15.3 ± 0.6%). The adsorption capacity is further enhanced by 39% (from 11.2 ± 1.1 to 15.6 ± 1.6 mg/g) by subjecting the NMSG to a magnetic field prior to adsorption. We infer that the magnetic field aligned the magnetic domains within the nano-magnetites, resulting in an increased Lorentz force during adsorption. Similar alignment of magnetic domains is near to impossible in pure nano-magnetites due to severe agglomeration. We further found that the adsorption capacity of the NMSG can be manipulated with an external magnetic field by varying the strength and the configurations of the field. Equipped with proper process design, our finding has great potentials in processes that involve ion-adsorptions, for example, NMSG can: (i) replace/reduce chemical dosing in controlling adsorption kinetics, (ii) replace/reduce complex chemicals required in ion-chromatography columns, and (iii) reduce wastage of nano-adsorbents by immobilizing it in a porous matrix.
    Matched MeSH terms: Silicon Dioxide
  15. Fulltext Efficacy of Several Plants Extracts on the Tunneling Activity and Survival of Subterranean Termites (Coptotermes gestroi and Globitermes sulphureus)
    Bakaruddin NH, Ab Majid AH
    Trop Life Sci Res, 2019 Jan;30(1):33-56.
    PMID: 30847032 MyJurnal DOI: 10.21315/tlsr2019.30.1.3
    This study examined the tunneling activity and the behaviour of two subterranean termites, Globitermes sulphurues and Coptotermes gestroi treated with four plant extracts, namely Pyllanthus niruri, Azadirachta indica, Leucaena leucocephala and Andrographis paniculata. All plants were extracted with three different solvents (methanol, hexane and water) and were diluted into three concentrations (500, 5,000 and 10,000 ppm). A group of 50 workers and 2 soldiers were tested and observed daily during the exposure in order to determine their survivorship and behaviour. Both sections were scored to determine their tunneling activities after seven days. There was a significant difference of tunneling activities of C. gestroi on sand treated with plant extracts (X2(2) = 31.790, p < 0.0001) with a mean rank of 8.50 for methanolic extracts and 32.50 for both hexane and water extracts. Meanwhile, no significant difference was observed on tunneling activity of G. sulphureus on treated sand (X2(2) = 2.200, p = 0.333) with a mean rank of 20.72 for methanolic extracts, 26.31 for water extracts and 26.47 for hexane extracts. Results showed that plants extracted with methanol demonstrated strong repellent properties with 0 tunneling activity on the treated sand and low survivorship of both termites. Moreover, both termites did not survive (0%) when they were treated with methanolic extracts at 10,000 ppm. They also displayed a different behaviour post-exposure such as avoidance, gradually losing the ability to walk and low feeding consumption. These results indicate that there is a strong termiticidal activity of plants extracted with methanol against C. gestroi and G. sulphureus.
    Matched MeSH terms: Silicon Dioxide
  16. Fulltext A case of trauma related Acanthamoeba keratitis
    Kamel AG, Faridah H, Yusof S, Norazah A, Nakisah MA
    Trop Biomed, 2004 Dec;21(2):135-8.
    PMID: 16493405 MyJurnal
    Acanthamoeba is an uncommon cause of keratitis but one of the most severe because of the prolonged and painful course of the disease and poor visual outcome. Although contact lens use is the principal risk factor, about 10% of cases occur following trauma and exposure to contaminated soil or water. Two cases of Acanthamoeba keratitis involving women contact lens wearers have previously been reported in Malaysia but this is the first time, a non contact lens related Acanthamoeba keratitis is reported. The case involved a 28 year old Indonesian male construction worker who had a trauma of the right eye during work. His eye was struck by sand and dust particles after which he quickly washed with water from an open tank at the construction site. He experienced pain, redness, glaring and blurring of vision of the right eye three days later. The diagnosis was missed at initial presentation but culture of the corneal scraping had proven Acanthamoeba as the aetiological agent. The history and clinical findings of this trauma related Acanthamoeba keratitis are briefly discussed.
    Matched MeSH terms: Silicon Dioxide
  17. Fulltext Morphology observation and physical properties of phenolic resin-silicate layered nanocomposites
    Norul Azlin, M.Z., Senin, H.B., Kok Sheng, C.
    Journal of Nuclear and Related Technologies, 2009;2009(1):121-134.
    MyJurnal
    Phenolic resin-silica nanocomposites samples in pellet shape have been successfully prepared by intercalation of polymer solution through the hot pressing method. The phenolic resin is modified with organic elastomers of silica nanoparticles, which is about 20 nanometer in diameter. The change of density and porosity was studied based on the addition of silica content in the phenolic resin composites. The densities of composites increased with the addition of the silica content from 10 wt.% to 40 wt.%. On the other hand, the porosity percentage was decreased with increasing of silica contents. The mechanical properties (Young’s modulus, energy to break and time to failure) of the nanocomposites samples were identified using the Universal Testing Material Machine (UTM). The results of Young’s modulus, energy to break and time to failure of the phenolic resin composites were found to be slightly increased with silica content from 10 wt.% to 30 wt.%. The X-Ray Microtomogaphy (XRM) topographies have shown that the porosity exists on fracture structure for each nanocomposite. The nanocomposites surface structure has been analyzed using Scanning Electron Microscope (SEM). The observation shows that the fracture surface of the pure phenolic resin is relatively smooth and glassy, which is typical for a brittle material, but the phenolic resin- silica composites fracture surface is not smooth at all. The observations indicate the pure phenolic resin is brittle than phenolic resin-silica nanocomposites. Consequently, the physical properties of the phenolic resin-silica nanocomposites were improved with the addition of 10 wt.% to 30 wt.% silica contents, as compared to that of the pure phenolic resin.
    Matched MeSH terms: Silicon Dioxide
  18. Fulltext Physical, chemical & mineralogical properties of fly ash
    Khairul Nizar Ismail, Kamarudin Hussin, Mohd Sobri Idris
    Journal of Nuclear and Related Technologies, 2007;2005(1):47-51.
    MyJurnal
    Fly ash is the finely divided mineral residue resulting from the combustion of coal in electric generating plants. Fly ash consists of inorganic, incombustible matter present in the coal that has been fused during combustion into a glassy, amorphous structure. Fly ash particles are generally spherical in shape and range in size from 2 μm to 10 μm. They consist mostly of silicon dioxide (SiO2), aluminium oxide (Al2O3) and iron oxide (Fe2O3). Fly ash like soil contains trace concentrations of the following heavy metals: nickel, vanadium, cadmium, barium, chromium, copper, molybdenum, zinc and lead. The chemical compositions of the sample have been examined and the fly ash are of ASTM C618 Class F.
    Matched MeSH terms: Silicon Dioxide
  19. Fulltext Respiratory symptoms and spirometry findings among pottery makers in Perak
    Ibrahim Zubil, AR., Wan Adnan W. A
    Journal of Occupational Safety and Health, 2013;10(1):49-58.
    MyJurnal
    Occupational health hazards as a result to exposure to mineral dust containing silica has been established long time ago in occupational health history. Its effects on lung function and symptom was evaluated in a cross sectional studied among 49 small enterprise pottery workers in the county of Sayong clustered in 3 villages. Respiratory symptoms and lung function was evaluated using MRC respiratory questionnaire 86 and standard spirometry performed. The prevalence of chronic cough, phlegm and chest tightness was 24.5%, 16% and16% respectively. There was no significant decrement in lung function parameters from the predicted normal value with the mean predicted FVC; FEV1 and FEV1/FVC ratio was 85.32%, 83.87% and 99.22 respectively. The relationship between lung symptoms and lung function parameters was evaluated and the result was not significant.
    Matched MeSH terms: Silicon Dioxide
  20. Doped silica fibre thermoluminescence measurements of radiation dose in the use of 223Ra
    Bradley, Sani SFA, Shafiqah ASS, Collins SM, Hugtenburg RP, Rashid HAA, et al.
    Appl Radiat Isot, 2018 Aug;138:65-72.
    PMID: 28427834 DOI: 10.1016/j.apradiso.2017.04.019
    Using tailor-made sub-mm dimension doped-silica fibres, thermoluminescent dosimetric studies have been performed for α-emitting sources of 223RaCl2 (the basis of the Bayer Healthcare product Xofigo®). The use of 223RaCl2 in the palliative treatment of bone metastases resulting from late-stage castration-resistant prostate cancer focuses on its favourable uptake in metabolically active bone metastases. Such treatment benefits from the high linear energy transfer (LET) and associated short path length (<100µm) of the α-particles emitted by 223Ra and its decay progeny. In seeking to provide for in vitro dosimetry of the α-particles originating from the 223Ra decay series, investigation has been made of the TL yield of various forms of Ge-doped SiO2 fibres, including photonic crystal fibre (PCF) collapsed, PCF uncollapsed, flat and single-mode fibres. Irradiations of the fibres were performed at the UK National Physical Laboratory (NPL). Notable features are the considerable sensitivity of the dosimeters and an effective atomic number Zeff approaching that of bone, the glass fibres offering the added advantage of being able to be placed directly into liquid. The outcome of present research is expected to inform development of doped fibre dosimeters of versatile utility, including for applications as detailed herein.
    Matched MeSH terms: Silicon Dioxide
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