Displaying publications 321 - 340 of 448 in total

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  1. Titanium addition influences antibacterial activity of bioactive glass coatings on metallic implants
    Rodriguez O, Stone W, Schemitsch EH, Zalzal P, Waldman S, Papini M, et al.
    Heliyon, 2017 Oct;3(10):e00420.
    PMID: 29034340 DOI: 10.1016/j.heliyon.2017.e00420
    In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn(2+)), which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro.
    Matched MeSH terms: Silicon Dioxide
  2. Fulltext Investigations on the Role of N₂:(N₂ + CH₄) Ratio on the Growth of Hydrophobic Nanostructured Hydrogenated Carbon Nitride Thin Films by Plasma Enhanced Chemical Vapor Deposition at Low Temperature
    Khanis NH, Ritikos R, Ahmad Kamal SA, Abdul Rahman S
    Materials (Basel), 2017 Jan 24;10(2).
    PMID: 28772460 DOI: 10.3390/ma10020102
    Nanostructured hydrogenated carbon nitride (CNx:H) thin films were synthesized on a crystal silicon substrate at low deposition temperature by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). Methane and nitrogen were the precursor gases used in this deposition process. The effects of N₂ to the total gas flow rate ratio on the formation of CNx:H nanostructures were investigated. Field-emission scanning electron microscopy (FESEM), Auger electron spectroscopy (AES), Raman scattering, and Fourier transform of infrared spectroscopies (FTIR) were used to characterize the films. The atomic nitrogen to carbon ratio and sp² bonds in the film structure showed a strong influence on its growth rate, and its overall structure is strongly influenced by even small changes in the N₂:(N₂ + CH₄) ratio. The formation of fibrous CNx:H nanorod structures occurs at ratios of 0.7 and 0.75, which also shows improved surface hydrophobic characteristic. Analysis showed that significant presence of isonitrile bonds in a more ordered film structure were important criteria contributing to the formation of vertically-aligned nanorods. The hydrophobicity of the CNx:H surface improved with the enhancement in the vertical alignment and uniformity in the distribution of the fibrous nanorod structures.
    Matched MeSH terms: Silicon
  3. Fulltext Initial testing of a pixelated silicon detector prototype in proton therapy
    Wroe AJ, McAuley G, Teran AV, Wong J, Petasecca M, Lerch M, et al.
    J Appl Clin Med Phys, 2017 Sep;18(5):315-324.
    PMID: 28719019 DOI: 10.1002/acm2.12120
    As technology continues to develop, external beam radiation therapy is being employed, with increased conformity, to treat smaller targets. As this occurs, the dosimetry methods and tools employed to quantify these fields for treatment also have to evolve to provide increased spatial resolution. The team at the University of Wollongong has developed a pixelated silicon detector prototype known as the dose magnifying glass (DMG) for real-time small-field metrology. This device has been tested in photon fields and IMRT. The purpose of this work was to conduct the initial performance tests with proton radiation, using beam energies and modulations typically associated with proton radiosurgery. Depth dose and lateral beam profiles were measured and compared with those collected using a PTW parallel-plate ionization chamber, a PTW proton-specific dosimetry diode, EBT3 Gafchromic film, and Monte Carlo simulations. Measurements of the depth dose profile yielded good agreement when compared with Monte Carlo, diode and ionization chamber. Bragg peak location was measured accurately by the DMG by scanning along the depth dose profile, and the relative response of the DMG at the center of modulation was within 2.5% of that for the PTW dosimetry diode for all energy and modulation combinations tested. Real-time beam profile measurements of a 5 mm 127 MeV proton beam also yielded FWHM and FW90 within ±1 channel (0.1 mm) of the Monte Carlo and EBT3 film data across all depths tested. The DMG tested here proved to be a useful device at measuring depth dose profiles in proton therapy with a stable response across the entire proton spread-out Bragg peak. In addition, the linear array of small sensitive volumes allowed for accurate point and high spatial resolution one-dimensional profile measurements of small radiation fields in real time to be completed with minimal impact from partial volume averaging.
    Matched MeSH terms: Silicon
  4. Fulltext Comparison of direct method and indirect methods for sampling and analysis of airborne respirable crystaline silica by X-ray difractometer
    Suhaily Amran, Ahmad Sayuti Zainal Abidin, Shoffian Amin Jaafar, Mohd Talib Latif, Abdul Mutalib Leman
    Journal of Occupational Safety and Health, 2015;12(1):137-141.
    MyJurnal
    There are several alternative sampling and analytical methods available for the determination of respirable
    crystalline silica exposure among workers. The commonly used ones are, (1) NIOSH Manual Analytical Method
    No.7500(NMAM 7500) which is Silica, crystalline, by X-ray difractometer via filter deposition(NIOSH 2003), and
    (2) MDHS 101 (Methods for the Determination of Hazardous Substances (MDHS) Guidance No.101: Respirable
    crystalline silica in respirable airborne dust). The aim of this study is to compare applicability of respirable crystalline
    silica sampling and analysis between method MDHS 101 and NMAM 7500. Laboratory procedures will be performed
    strictly based on MDHS 101 and NMAM 7500. Both methods apply X-ray diffraction as analytical technique with
    many variations on sampling techniques and laboratory preparations. Quality assurance values such as detection
    limits, accuracy and precision are derived from both data and will be compared to determine which of the method
    establishes better quality assurance. The method which establishes better quality assurance will be recommend to be
    used in Malaysian respirable crystalline silica monitoring programme. The strength of this research lies on its potential
    to provide local capabilities in analysis of respirable crystalline silica in Malaysian setting.
    Matched MeSH terms: Silicon Dioxide
  5. Fulltext Sustainable green interlocking pavement block
    Umar Kassim, Omar Mohd Rohim
    Journal of Advanced Research in Applied Sciences and Engineering Technology, 2017;8(1):1-7.
    MyJurnal
    In accordance upon conservation efforts, this research emphasizes on prevention of
    environmental pollution and considers the elements of sustainable of infrastructure
    construction materials, which is interlocking pavement block. The development of this
    innovative product apply the concept of 3Rs and waste to wealth by using the
    agricultural waste product, coconut shell, where widely available with very minimum
    cost worldwide especially in tropical country such as India, Indonesia, Philippines,
    Thailand and Malaysia. The main objective of this research is to produce an
    environmental friendly product with a good quality, low cost and lightweight known as
    Green Interlocking Pavement (GIP Block). The chemical composition of coconut shell
    ash and ordinary Portland cement being identified and compared to know whether it
    is able to react as a good binder in the mixture or not. The quality of GIP Block
    considered is compressive strength, water absorption and bulk density. All the blocks
    were curing in seven and 28 days before implementing the entire test. The existing
    interlocking pavement used as bench mark and GIP Block 0% of proportion of coconut
    shell ash used as control variables. The specimen of the interlocking pavement
    prepared in this research is 10%, 20% and 30% proportion of coconut shell ash to
    partially replace the quantity of cement. The ratio of the interlocking pavement apply
    in this research is 1:2 which stand for one part cement and two part of sand. The
    findings withdrawn from this research are: first, the chemical characteristic of the
    coconut shell ash and cement. Second, the value of bulk density slightly reduces as the
    percentage of coconut shell ash increases. Third, the additional of coconut shell ash to
    partially replace the quantity of cement in the product reduce the compressive
    strength and increase the percentage of water absorption.
    Matched MeSH terms: Silicon Dioxide
  6. Fulltext Biocompatibility assessment of fabricated melt-derived 45S5 bioactive glass on dental cells proliferation
    Mohd Zain N.S., Tajudin S.S., Mohd Noor S.N.F., Mohamad H.
    Journal of Biomedical and Clinical Sciences, 2016;1(1):26-32.
    MyJurnal
    Thisstudy aim tocharacterize melt-derivedbioactive glass and to determinethe bioactive glass (BG) suitability for dental usagethrough proliferative activity assessment of stem cells from human exfoliated deciduous teeth (SHED)when exposed to bioactive glass conditioned medium. Bioglass 45S5 in mole percentages (46.13% SiO2, 26.91% CaO, 24.35% Na2O and 2.60% P2O5)was synthesizedthrough melt-derived and characterized usingX-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR)to confirm and identify its properties.SHEDwere used to evaluate the biocompatibility of 45S5 by exposing the cells to various concentration of BG-conditioned medium (1-10 mg/ml) using alamarBlue assay. The BG produced has an amorphous structureas shown by XRD analysis. TheSi-O-Si bending, asymmetric Si-O stretching and asymmetricSi-O-Si stretchingbands were observed in the BG structure supporting the presenceof silicate network. For alamarBlue assay, SHED cultured in BG-conditioned medium showed high proliferation rate when subjected to minimal powder content in the DMEM cell culture medium.Hence, it can be concluded that SHED cultured in lower powder content of the BG-conditioned media showedhigh proliferative activity suggesting the potential of the BG for dental usage.
    Matched MeSH terms: Silicon Dioxide
  7. Tailoring the Properties of Metal Oxide Loaded/KCC-1 toward a Different Mechanism of CO2 Methanation by in Situ IR and ESR
    Shahul Hamid MY, Triwahyono S, Jalil AA, Che Jusoh NW, Izan SM, Tuan Abdullah TA
    Inorg Chem, 2018 May 21;57(10):5859-5869.
    PMID: 29746104 DOI: 10.1021/acs.inorgchem.8b00241
    Nickel (Ni), cobalt (Co), and zinc (Zn) loaded on fibrous silica KCC-1 was investigated for CO2 methanation reactions. Ni/KCC-1 exhibits the highest catalyst performance with a CH4 formation rate of 33.02 × 10-2 molCH4 molmetal-1 s-1, 1.77 times higher than that of Co/KCC-1 followed by Zn/KCC-1 and finally the parent KCC-1. A pyrrole adsorption FTIR study reveals shifting of perturbed N-H stretching decreasing slightly with the addition of metal oxide, suggesting that the basic sites of catalyst were inaccessible due to metal oxide deposition. The strengths of basicity were found to follow sthe equence KCC-1, Ni/KCC-1, Zn/KCC-1, and Co/KCC-1. The data were supported by N2 adsorption desorption analysis, where Co/KCC-1 displayed the greatest reduction in total surface area whereas Ni/KCC-1 displayed the least reduction. The elucidation of difference mechanism pathways has also been studied by in situ IR spectroscopy studies to determine the role of different metal oxides in CO2 methanation. It was discovered that Ni/KCC-1 and Co/KCC-1 follow a dissociative mechanism of CO2 methanation in which the CO2 molecule was dissociated on the surface of the metal oxide before migration onto the catalyst surface. This was confirmed by the evolution of a peak corresponding to carbonyl species (COads) on a metal oxide surface in FTIR spectra. Zn/KCC-1, on the other hand, showed no such peak, indicating associative methanation pathways where a hydrogen molecule interacts with an O atom in CO2 to form COads and OH. These results offers a better understanding for catalytic studies, particularly in the field of CO2 recycling.
    Matched MeSH terms: Silicon Dioxide
  8. Fulltext FEM Analysis of Sezawa Mode SAW Sensor for VOC Based on CMOS Compatible AlN/SiO₂/Si Multilayer Structure
    Aslam MZ, Jeoti V, Karuppanan S, Malik AF, Iqbal A
    Sensors (Basel), 2018 May 24;18(6).
    PMID: 29882929 DOI: 10.3390/s18061687
    A Finite Element Method (FEM) simulation study is conducted, aiming to scrutinize the sensitivity of Sezawa wave mode in a multilayer AlN/SiO₂/Si Surface Acoustic Wave (SAW) sensor to low concentrations of Volatile Organic Compounds (VOCs), that is, trichloromethane, trichloroethylene, carbon tetrachloride and tetrachloroethene. A Complimentary Metal-Oxide Semiconductor (CMOS) compatible AlN/SiO₂/Si based multilayer SAW resonator structure is taken into account for this purpose. In this study, first, the influence of AlN and SiO₂ layers’ thicknesses over phase velocities and electromechanical coupling coefficients (k²) of two SAW modes (i.e., Rayleigh and Sezawa) is analyzed and the optimal thicknesses of AlN and SiO₂ layers are opted for best propagation characteristics. Next, the study is further extended to analyze the mass loading effect on resonance frequencies of SAW modes by coating a thin Polyisobutylene (PIB) polymer film over the AlN surface. Finally, the sensitivity of the two SAW modes is examined for VOCs. This study concluded that the sensitivity of Sezawa wave mode for 1 ppm of selected volatile organic gases is twice that of the Rayleigh wave mode.
    Matched MeSH terms: Silicon Dioxide
  9. Fulltext Synthesis of Ge1-xSnx Alloy Thin Films by Rapid Thermal Annealing of Sputtered Ge/Sn/Ge Layers on Si Substrates
    Mahmodi H, Hashim MR, Soga T, Alrokayan S, Khan HA, Rusop M
    Materials (Basel), 2018 Nov 12;11(11).
    PMID: 30424494 DOI: 10.3390/ma11112248
    In this work, nanocrystalline Ge1-xSnx alloy formation from a rapid thermal annealed Ge/Sn/Ge multilayer has been presented. The multilayer was magnetron sputtered onto the Silicon substrate. This was followed by annealing the layers by rapid thermal annealing, at temperatures of 300 °C, 350 °C, 400 °C, and 450 °C, for 10 s. Then, the effect of thermal annealing on the morphological, structural, and optical characteristics of the synthesized Ge1-xSnx alloys were investigated. The nanocrystalline Ge1-xSnx formation was revealed by high-resolution X-ray diffraction (HR-XRD) measurements, which showed the orientation of (111). Raman results showed that phonon intensities of the Ge-Ge vibrations were improved with an increase in the annealing temperature. The results evidently showed that raising the annealing temperature led to improvements in the crystalline quality of the layers. It was demonstrated that Ge-Sn solid-phase mixing had occurred at a low temperature of 400 °C, which led to the creation of a Ge1-xSnx alloy. In addition, spectral photo-responsivity of a fabricated Ge1-xSnx metal-semiconductor-metal (MSM) photodetector exhibited its extending wavelength into the near-infrared region (820 nm).
    Matched MeSH terms: Silicon
  10. Sealants revisited: An efficacy battle between the two major types of sealants - A randomized controlled clinical trial
    Prathibha B, Reddy PP, Anjum MS, Monica M, Praveen BH
    Dent Res J (Isfahan), 2019 2 13;16(1):36-41.
    PMID: 30745917
    Background: The aim of this study is comparing the retention and caries preventive effect of the glass-ionomer fissure sealant and resin-based fissure sealant.

    Materials and Methods: A randomized-controlled split-mouth study was conducted to compare the retention and the caries preventive effect of light-cured resin-based sealant (3M ESPE) and glass ionomer sealant (Fuji VII). The sealants were applied to either the right or the left lower mandibular molars (7-9 yrs of age) in 120 school children, based on the randomization process. They were recalled for assessment of clinical retention at intervals of 3, 6, and 12 months. The caries-preventive effect between the two materials was tested statistically by the McNemar's test for matched pairs, and the differences observed with regard to the retention of the materials was tested by Chi-square tests. The level of significance was set to be at P < 0.05.

    Results: At the end of 12th month, sealant retention is found to be higher in the resin-based sealant group compared to the glass ionomer group. In the glass ionomer sealants placed, 101 (91%) were caries-free and 10 (9%) had caries. In the resin-based sealant, 105 (94.60%) had sound teeth and 6 (5.4%) had dental caries (P = 0.34).

    Conclusion: The glass ionomer sealant was less retentive when compared to resin sealants. The caries incidence between the glass ionomer and resin-based sealants was not statistically significant.

    Matched MeSH terms: Silicon Dioxide
  11. Membrane distillation of saline and oily water using nearly superhydrophobic PVDF membrane incorporated with SiO2 nanoparticles
    Hamzah N, Nagarajah M, Leo CP
    Water Sci Technol, 2018 Dec;78(12):2532-2541.
    PMID: 30767918 DOI: 10.2166/wst.2019.016
    Fat, oil and grease in wastewater generated from household kitchens, restaurants and food processing plants affect sewer systems, water resources and environment adversely. Hence, membrane distillation of saline and oily water was studied using a nearly superhydrophobic membrane developed in this work. Polyvinylidene fluoride (PVDF) membrane incorporated SiO2 nanoparticles was synthesized via phase inversion with dual baths and modified using hexadecyltrimethoxy silane. The volume ratio of silane to ethanol was varied between 1:200 to 1:25. The membrane characteristics were examined using a goniometer, a porometer, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The PVDF-SiO2 membrane modified using the volume ratio of 1:50 achieved the highest water contact angle of 141.6° and LEP of 2.642 bar. This membrane was further tested in membrane distillation to observe the permeate flux of distilled water, saline solution (1 M NaCl) as well as saline and oily solution (1 M NaCl; 1,000 ppm of palm oil). The modified PVDF/SiO2 showed high permeate flux which is nearly four times of the permeate flux of neat PVDF membrane, but still susceptible of salt and oil fouling as shown in SEM images.
    Matched MeSH terms: Silicon Dioxide
  12. Effects of the nitric acid concentrations on the etching process, structural and optical properties of porous zinc oxide thin films
    C.G. Ching, Leonard Lu, C.I. Ang, P.K. Ooi, S.S. Ng, Z. Hassan, et al.
    Sains Malaysiana, 2013;42:1327-1332.
    The present study reports on the fabrication of porous zinc oxide by wet chemical etching. ZnO thin films were deposited via radio-frequency magnetron sputtering on p-type silicon with (111) preferred orientation. The etchants used in the present work were 0.1% and 1.0% nitric acid (HNO3) solutions. ZnO were etched at various times and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy to allow the examination of their structural and optical properties. The XRD results revealed that the intensity of ZnO(002) decreased when the thin films were etched in varying HNO3 concentrations over different periods of time. The above observation is attributed to the dissolution of the ZnO(002). The SEM images showed that the thickness of the ZnO layers decreased over the etching time, which resulted from the isotropic etching by the HNO3 solution. The PL emission intensity initially increased with increasing etching time. However, with further etching of the samples, the PL spectra showed a decreasing trend in intensity as a result of the decrease in the surface-to-volume ratio. All results lead to the conclusion that 1.0% HNO3 has the capability to change the ZnO surface significantly.
    Matched MeSH terms: Silicon
  13. Natural dye-sensitized solar cell based on nanocrystalline TiO2
    Khalil Ebrahim Jasim
    Sains Malaysiana, 2012;41:1011-1016.
    During the last quarter of the twentieth century there have been intensive research activities looking for green sources of energy. The main aim of the green generators or converters of energy is to replace the conventional (fossil) energy sources, hence reducing further accumulation of the green house gasses GHGs. Conventional silicon and III-V semiconductor solar cell based on crystalline bulk, quantum well and quantum dots structure or amorphous and thin film structures provided a feasible solution. However, natural dye sensitized solar cells NDSSC are a promising class of photovoltaic cells with the capability of generating green energy at low production cost since no vacuum systems or expensive equipment are required in their fabrication. Also, natural dyes are abundant, easily extracted and safe materials. In NDSSC, once dye molecules exposed to light they become oxidized and transfer electrons to a nanostructured layer of wide bandgap semiconductors such as TiO2. The generated electrons are drawn outside the cell through ohmic contact to a load. In this paper we review the structure and operation principles of the dye sensitized solar cell DSSC. We discuss preparation procedures, optical and electrical characterization of the NDSSC using local dyes extracted from Henna (lawsonia inermis L.), pomegranate, cherries and Bahraini raspberries (rubus spp.). These natural organic dyes are potential candidates to replace some of the man-made dyes used as sensitizer in many commercialized photoelectrochemical cells. Factors limiting the operation of the DSSC are discussed. NDSSCs are expected to be a favored choice in the building-integrated
    photovoltaics (BIPV) due to their robustness, therefore, requiring no special shielding from natural events such as tree strikes or hails.
    Matched MeSH terms: Silicon
  14. Controlled-growth of ZnO nanowires with different processing temperature
    Yap CC, Muhammad Yahaya, Muhamad Mat Salleh, Dee CF
    Sains Malaysiana, 2008;37:233-237.
    ZnO nanowires have been synthesized using a catalyst-free carbothermal reduction approach on SiO2-coated Si substrates in a flowing nitrogen atmosphere with a mixture of ZnO and graphite as reactants. The collected ZnO nanowires have been characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and photoluminescence spectroscopy. Controlled growth of the ZnO nanowires was achieved by manipulating the reactants heating temperature from 700 to 1000 oC. It was found that the optimum temperature to synthesize high density and long ZnO nanowires was about 800 0C. The possible growth mechanism of ZnO nanowires is also proposed.
    Matched MeSH terms: Silicon Dioxide
  15. Engineering geological properties of oil-contaminated granitic and metasedimentary soils
    Zulfahmi Ali Rahman, Umar Hamzah, Noorulakma Ahmad
    Sains Malaysiana, 2011;40.
    Hydrocarbon is a light-non aqueous phase liquid or known as LNAPL. It poses environmental hazard if accidentally spilled out into the soil and water systems as a result of its insoluble nature in water. LNAPL component infiltrates into soil through pore spaces and afloat at the top of groundwater level. Some of this hydrocarbon would trap and clog within the voids, difficult to remove and costly to clean. The occurence of hydrocarbon in the soil definitely degraded the behaviour of soils in terms of engineering properties. This study aimed to investigate the engineering properties of oil-contaminated soil for two different residual soils originally developed from in-situ weathering of granitic and metasedimentary rocks. The physical characterisations of the soil were determined including particle size distribution, specific gravity test and x-ray diffraction (XRD). The engineering parameters for the contaminated and uncontaminated soils were Atterberg limits, compaction and soil shear strength (UU tests). The amounts of hydrocarbon added to soil were varied at 0%, 4%, 8%, 12% and 16% of dried weigth of soil samples. The results from the particle size distribution analysis showed that residual soil from granitic rock comprises of 38% sand, 33% silt and 4% clay while metasedimentary soil consists of 4% sand, 43% silt dan 29% clay. The mean values of specific gravity for the granitic and metasedimentary soils were 2.56 and 2.61, respectively. The types of minerals present in granitic soil sample were quartz, kaolinite and gibbsite while metasedimentary soil consists of quartz and kaolinite. The Atterberg limits value decreased as a result of increasing amount of added hydrocarbon into the soil. A similar behaviouir was observed with the values of maximum dry density and optimum water content with increasing hydrocarbon content. The overall unconsolidated undrained shear strength, Cu showed a decreasing trend with the increase in hydrocarbon content.
    Matched MeSH terms: Silicon Dioxide
  16. Corrosion protection of carbon steel using polyaniline composite with inorganic pigments
    Al-Dulaimi AA, Shahrir Hashim, Khan M
    Sains Malaysiana, 2011;40:1179-1186.
    Two inorganic pigments (TiO2 and SiO2) were used to prepare composites with polyaniline (PANI) by situ polymerization method. PANI and PANI composites with SiO2 and TiO2 were characterized using Fourier transform infrared spectroscopy and X-ray diffraction. The morphology of the synthesized pigments (PANI , PANI-SiO2 and PANI-TiO2) was examined using scanning electron microscopy. Samples were then used as pigments through blending them with acrylic paint and applied on the surface of carbon steel panels. Corrosion was evaluated for coating of carbon steel panels through full immersion test up to standard ASTMG 31. Mass loss was calculated after they have been exposed in acidic media. A digital camera was also used for monitoring corrosion visually on the surface of carbon steel specimens. The results revealed that acrylic paint pigmented by PANI-SiO2 composite was more efficient in corrosion protection for carbon steel compared with the other synthesized pigments.
    Matched MeSH terms: Silicon Dioxide
  17. 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
  18. Characterization of hydrocarbons in smoke aerosols from burning of three tropical wood species
    Tan hs, Mohd Radzi Abas, Norhayati Mohd Tahir
    Sains Malaysiana, 2016;45:365-371.
    A study has been carried out to characterize hydrocarbons emitted from the burning of three tropical wood species. The woods were burned to ember and smoke aerosols emitted were sampled using high volume sampler fitted with a pre-cleaned glass fibre filters. Hydrocarbons were extracted using ultrasonic agitation with dichloromethane-methanol (3:1 v/v) as solvent and the extracts obtained were then fractionated on silica-alumina column. Detection and quantification of aliphatic and polycyclic aromatic hydrocarbons (PAHs) compounds were carried out using GC-MS. The results indicated that the major aliphatic hydrocarbons characterized were straight chain n-alkanes in the range of C12-C35 with Cmax in the range of C27-C33. Rhizophora apiculata and Hevea brasiliensis wood smoke exhibited a weak odd to even carbon number predominance with carbon preference index (CPI) values greater than one whereas Melaleuca cajuputi wood smoke aerosols did not exhibit similar pattern with CPI obtained close to one. The results obtained also indicated that burning of these wood resulted in formation of PAHs compounds in their smoke aerosols with predominance of three to four rings PAHs over the two, five and lesser of six rings PAHs. PAH diagnostic ratios calculated except for Flan/(Flan+Py) and Indeno/(Indeno+BgP) were consistent with the ratios suggested for wood combustion source as reported in literatures. In the case of the latter, two diagnostic ratios, the values were generally lower than the range normally reported for wood combustion.
    Matched MeSH terms: Silicon Dioxide
  19. Anticorrosive properties of nano silicate from paddy husk in salt medium
    Norinsan Kamil Othman, Solhan Yahya, Denni Asra Awizar
    Sains Malaysiana, 2016;45:1253-1258.
    Anticorrosive properties of nano silicate from paddy husk in salt medium was investigated via weight loss method, Tafel
    polarization and impedance techniques. Prior to the corrosion test, the silica powder was obtained from burning the
    rice husk and extended with a chemical treatment process. The size of silica powder was characterized via zeta sizer and
    showed the amount of micro silica particle appear more than the nano size particle. Nano silica powder was produced
    from the refluxing process of micro silica to enhance the good properties of silica particle. The corrosion inhibition
    efficiency of nano silicate showed good inhibition with increased in inhibitor concentrations. Weight loss test exhibits
    high inhibition as more than 80% even, immersed in the corrosive medium until 14 days. The nano silicate inhibitor
    affected the anodic reaction as showed by Tafel plot analysis. Impedance results also correlated with other test as shown
    by the large size of Nyquist semicircle which represents as high resistance of charge transfer. The surface morphology
    of inhibited specimen showed a smooth surface after nano silicate inhibitor applied in the NaCl medium as observed
    through scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX).
    Matched MeSH terms: Silicon Dioxide
  20. 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
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