Displaying publications 1 - 20 of 85 in total

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  1. Removal of bisphenol A by adsorption mechanism using PES-SiO2 composite membranes
    Muhamad MS, Salim MR, Lau WJ, Hadibarata T, Yusop Z
    Environ Technol, 2016 Aug;37(15):1959-69.
    PMID: 26729509 DOI: 10.1080/09593330.2015.1137359
    Polyethersulphone (PES) membranes blended with silicon dioxide (SiO2) nanoparticles were prepared via a dry-jet wet spinning technique for the removal of bisphenol A (BPA) by adsorption mechanism. The morphology of SiO2 nanoparticles was analysed using a transmission electron microscopy and particle size distribution was also analysed. The prepared membranes were characterized by several techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy and water contact angle. The adsorption mechanism of membrane towards BPA was evaluated by batch experiments and kinetic model. The influence of natural organic matter (NOM) in feed water on membrane BPA removal was also studied by filtration experiments. Results showed that BPA adsorption capacity as high as 53 µg/g could be achieved by the PES membrane incorporated with 2 wt% SiO2 in which the adsorption mechanism was in accordance with the pseudo-second-order kinetic model. The intraparticles diffusion model suggested that the rate limiting factor of membrane adsorption mechanism is governed by the diffusion of BPA into the membrane pores. The presence of 10 ppm NOM has reported to negatively reduce BPA removal by 24%, as it tended to compete with BPA for membrane adsorption. This work has demonstrated that PES-SiO2 membrane has the potential to eliminate trace amount of BPA from water source containing NOM.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  2. Fulltext Modeling and analysis of a microresonating biosensor for detection of Salmonella bacteria in human blood
    Bahadoran M, Noorden AF, Chaudhary K, Mohajer FS, Aziz MS, Hashim S, et al.
    Sensors (Basel), 2014;14(7):12885-99.
    PMID: 25046015 DOI: 10.3390/s140712885
    A new photonics biosensor configuration comprising a Double-side Ring Add-drop Filter microring resonator (DR-ADF) made from SiO2-TiO2 material is proposed for the detection of Salmonella bacteria (SB) in blood. The scattering matrix method using inductive calculation is used to determine the output signal's intensities in the blood with and without presence of Salmonella. The change in refractive index due to the reaction of Salmonella bacteria with its applied antibody on the flagellin layer loaded on the sensing and detecting microresonator causes the increase in through and dropper port's intensities of the output signal which leads to the detection of SB in blood. A shift in the output signal wavelength is observed with resolution of 0.01 nm. The change in intensity and shift in wavelength is analyzed with respect to the change in the refractive index which contributes toward achieving an ultra-high sensitivity of 95,500 nm/RIU which is almost two orders higher than that of reported from single ring sensors and the limit of detection is in the order of 1 × 10(-8) RIU. In applications, such a system can be employed for a high sensitive and fast detection of bacteria.
    Matched MeSH terms: Silicon Dioxide/chemistry
  3. Detection of Salmonella bacterium in drinking water using microring resonator
    Bahadoran M, Noorden AF, Mohajer FS, Abd Mubin MH, Chaudhary K, Jalil MA, et al.
    Artif Cells Nanomed Biotechnol, 2016;44(1):315-21.
    PMID: 25133457 DOI: 10.3109/21691401.2014.948549
    A new microring resonator system is proposed for the detection of the Salmonella bacterium in drinking water, which is made up of SiO2-TiO2 waveguide embedded inside thin film layer of the flagellin. The change in refractive index due to the binding of the Salmonella bacterium with flagellin layer causes a shift in the output signal wavelength and the variation in through and drop port's intensities, which leads to the detection of Salmonella bacterium in drinking water. The sensitivity of proposed sensor for detecting of Salmonella bacterium in water solution is 149 nm/RIU and the limit of detection is 7 × 10(-4)RIU.
    Matched MeSH terms: Silicon Dioxide/chemistry
  4. Fulltext Ultrasound-assisted sequentially precipitated nickel-silica catalysts and its application in the partial hydrogenation of edible oil
    Lim MSW, Yang TC, Tiong TJ, Pan GT, Chong S, Yap YH
    Ultrason Sonochem, 2021 May;73:105490.
    PMID: 33609992 DOI: 10.1016/j.ultsonch.2021.105490
    Sequentially precipitated Mg-promoted nickel-silica catalysts with ageing performed under various ultrasonic intensities were employed to study the catalyst performance in the partial hydrogenation of sunflower oil. Results from various characterisation studies showed that increasing ultrasonic intensity caused a higher degree of hydroxycarbonate erosion and suppressed the formation of Ni silicates and silica support, which improved Ni dispersion, BET surface area and catalyst reducibility. Growth of silica clusters on the catalyst aggregates were observed in the absence of ultrasonication, which explained the higher silica and nickel silicate content on the outer surface of the catalyst particle. Application of ultrasound also altered the electron density of the Ni species, which led to higher activity and enhanced product selectivity for sonicated catalysts. The catalyst synthesised with ultrasonic intensity of 20.78 Wcm-2 achieved 22.6% increase in hydrogenation activity, along with 28.5% decrease in trans-C18:1 yield at IV = 70, thus supporting the feasibility of such technique.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  5. Fulltext Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample
    Muraoka M, Susuki N, Yamaguchi H, Tsuji T, Yamamoto Y
    J Vis Exp, 2016 Mar 21.
    PMID: 27023374 DOI: 10.3791/53956
    Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates. The thermal properties' measurements of samples comprising sand, water, methane, and MH are difficult because the melting heat of MH may affect the measurements. To solve this problem, we performed thermal properties' measurements at supercooled conditions during MH formation. The measurement protocol, calculation method of the saturation change, and tips for thermal constants' analysis of the sample using transient plane source techniques are described here. The effect of the formation heat of MH on measurement is very small because the gas hydrate formation rate is very slow. This measurement method can be applied to the thermal properties of the gas hydrate-water-guest gas system, which contains hydrogen, CO2, and ozone hydrates, because the characteristic low formation rate of gas hydrate is not unique to MH. The key point of this method is the low rate of phase transition of the target material. Hence, this method may be applied to other materials having low phase-transition rates.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  6. Molecularly imprinted silica gel incorporated with agarose polymer matrix as mixed matrix membrane for separation and preconcentration of sulfonamide antibiotics in water samples
    Rozaini MNH, Semail NF, Saad B, Kamaruzaman S, Abdullah WN, Rahim NA, et al.
    Talanta, 2019 Jul 01;199:522-531.
    PMID: 30952293 DOI: 10.1016/j.talanta.2019.02.096
    Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1-500 μg L-1) with a coefficient of determination (R2) of 0.9959-0.9999, low limits of detection (0.06-0.17 μg L-1) and limits of quantification (0.20-0.56 μg L-1), good analyte recoveries (80-96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  7. MCM-41 solid phase membrane tip extraction combined with liquid chromatography for the determination of non-steroidal anti-inflammatory drugs in human urine
    Kamaruzaman S, Sanagi MM, Endud S, Wan Ibrahim WA, Yahaya N
    J Chromatogr B Analyt Technol Biomed Life Sci, 2013 Dec 1;940:59-65.
    PMID: 24140656 DOI: 10.1016/j.jchromb.2013.09.017
    Mesoporous silica material, MCM-41, was utilized for the first time as an adsorbent in solid phase membrane tip extraction (SPMTE) of non-steroidal anti-inflammatory drugs (NSAIDs) in urine prior to high performance liquid chromatography-ultraviolet (HPLC-UV) analysis. The prepared MCM-41 material was enclosed in a polypropylene membrane tip and used as an adsorbent in SPMTE. Four NSAIDs namely ketoprofen, diclofenac, mefenamic acid and naproxen were selected as model analytes. Several important parameters, such as conditioning solvent, sample pH, salting-out effect, sample volume, extraction time, desorption solvent and desorption time were optimized. Under the optimum extraction conditions, the MCM-41-SPMTE method showed good linearity in the range of 0.01-10μg/mL with excellent correlation coefficients (r=0.9977-0.9995), acceptable RSDs (0.4-9.4%, n=3), good limits of detection (5.7-10.6μg/L) and relative recoveries (81.4-108.1%). The developed method showed a good tolerance to biological sample matrices.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  8. Fulltext Green synthesis and characterization of UKMRC-8 rice husk-derived mesoporous silica nanoparticle for agricultural application
    Dorairaj D, Govender N, Zakaria S, Wickneswari R
    Sci Rep, 2022 Nov 23;12(1):20162.
    PMID: 36424408 DOI: 10.1038/s41598-022-24484-z
    Agriculture plays a crucial role in safeguarding food security, more so as the world population increases gradually. A productive agricultural system is supported by seed, soil, fertiliser and good management practices. Food productivity directly correlates to the generation of solid wastes and utilization of agrochemicals, both of which negatively impact the environment. The rice and paddy industry significantly adds to the growing menace of waste management. In low and middle-income countries, rice husk (RH) is an underutilized agro-waste discarded in landfills or burned in-situ. RH holds enormous potential in the development of value-added nanomaterials for agricultural applications. In this study, a simple and inexpensive sol-gel method is described to extract mesoporous silica nanoparticles (MSNs) from UKMRC8 RH using the bottom-up approach. RHs treated with hydrochloric acid were calcinated to obtain rice husk ash (RHA) with high silica purity (> 98% wt), as determined by the X-ray fluorescence analysis (XRF). Calcination at 650 °C for four hours in a box furnace yielded RHA that was devoid of metal impurities and organic matter. The X-ray diffraction pattern showed a broad peak at 2θ≈20-22 °C and was free from any other sharp peaks, indicating the amorphous property of the RHA. Scanning electron micrographs (SEM) showed clusters of spherically shaped uniform aggregates of silica nanoparticles (NPs) while transmission electron microscopy analysis indicated an average particle size of 
    Matched MeSH terms: Silicon Dioxide/chemistry
  9. Effects of co-substrate and biomass acclimation concentration on the bioregeneration of azo dye-loaded mono-amine modified silica
    Al-Amrani WA, Lim PE, Seng CE, Wan Ngah WS
    Bioresour Technol, 2013 Sep;143:584-91.
    PMID: 23835263 DOI: 10.1016/j.biortech.2013.06.055
    Bioregeneration of mono-amine modified silica gel (MAMS) adsorbent loaded with Acid Orange 7 (AO7), Acid Yellow 9 (AY9) and Acid Red 14 (AR14), respectively, was investigated under two different operational conditions, namely absence/presence of sucrose/bacto-peptone as the co-substrate and different biomass acclimation concentrations. The results revealed that the AY9- and AR14-loaded MAMS adsorbents could almost be completely bioregenerated but only in the presence of co-substrate whereas the bioregeneration of AO7-loaded MAMS could achieve up to 71% in the absence of the co-substrate. These differences could be related to the structural properties of the investigated azo dyes. In addition, the results showed that the bioregeneration duration of AO7-loaded MAMS could be progressively shortened by using biomass acclimated to increasingly higher AO7 concentration. However, the bioregeneration efficiencies were found to be relatively unchanged under different biomass acclimation concentrations.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  10. Robust Magnetized Oil Palm Leaves Ash Nanosilica Composite as Lipase Support: Immobilization Protocol and Efficacy Study
    Onoja E, Wahab RA
    Appl Biochem Biotechnol, 2020 Oct;192(2):585-599.
    PMID: 32495234 DOI: 10.1007/s12010-020-03348-0
    Strategies to immobilize the individual enzymes are crucial for enhancing catalytic applicability and require a controlled immobilization process. Herein, protocol for immobilizing Candida rugosa lipase (CRL) onto modified magnetic silica derived from oil palm leaves ash (OPLA) was optimized for the effects of concentration of CRL, immobilization time, and temperature, monitored by titrimetric and spectrometric methods. XRD and TGA-DTG spectrometric observations indicated that OPLA-silica was well coated over magnetite (SiO2-MNPs) and CRLs were uniformly bound by covalent bonds to SiO2-MNPs (CRL/Gl-A-SiO2-MNPs). The optimized immobilization protocol showed that in the preparation of CRL/Gl-A-SiO2-MNPs, CRL with 68.3 mg/g protein loading and 74.6 U/g specific activity was achieved using 5 mg/mL of CRL, with an immobilization time of 12 h at 25 °C. The present work also demonstrated that acid-pretreated OPLA is a potential source of renewable silica, envisioning its applicability for practical use in enzymatic catalysis on solid support.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  11. Extraction of nanosilica from oil palm leaves and its application as support for lipase immobilization
    Onoja E, Chandren S, Razak FIA, Wahab RA
    J Biotechnol, 2018 Oct 10;283:81-96.
    PMID: 30063951 DOI: 10.1016/j.jbiotec.2018.07.036
    The study reports the preparation of a composite consisting of magnetite coated with nanosilica extracted from oil palm leaves (OPL) ash as nanosupports for immobilization of Candida rugosa lipase (CRL) and its application for the synthesis of butyl butyrate. Results of immobilization parameters showed that ∼ 80% of CRL (84.5 mg) initially offered was immobilized onto the surface of the nanosupports to yield a maximum protein loading and specific activity of 67.5 ± 0.72 mg/g and 320.8 ± 0.42 U/g of support, respectively. Surface topography, morphology as well as information on surface composition obtained by Raman spectroscopy, atomic force microscopy, field emission scanning electron microscopy and transmission electron microscopy showed that CRL was successfully immobilized onto the nanosupports, affirming its biocompatibility. Under optimal conditions (3.5 mg/mL protein loading, at 45 ℃, 3 h and molar ratio 2:1 (1-butanol:n-butyric acid) the CRL/Gl-A-SiO2-MNPs gave a maximum yield of 94 ± 0.24% butyl butyrate as compared to 84 ± 0.32% in the lyophilized CRL. CRL/Gl-A-SiO2-MNPs showed an extended operational stability, retaining 50% of its initial activity after 17 consecutive esterification cycles. The results indicated that OPL derived nanosilica coated on magnetite can potentially be employed as carrier for lipase immobilization in replacement of the non-renewable conventionalsilica sources.
    Matched MeSH terms: Silicon Dioxide/chemistry
  12. The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons
    Hashim S, Bradley DA, Saripan MI, Ramli AT, Wagiran H
    Appl Radiat Isot, 2010 Apr-May;68(4-5):700-3.
    PMID: 19892557 DOI: 10.1016/j.apradiso.2009.10.027
    This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO(2) optical fibres subjected to (241)AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the (241)AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being made to entirely enclose the fibres). The neutron irradiations were performed for exposure times of 1-, 2-, 3-, 5- and 7-days in a neutron tank filled with water. In this study, use was also made of the Monte Carlo N-particle (MCNP) code version 5 (V5) to simulate the neutron irradiations experiment. It was found that the commercially available Ge-doped and Al-doped optical fibres show a linear dose response subjected to fast neutrons from (241)AmBe source up to seven days of irradiations. The simulation performed using MCNP5 also exhibits a similar pattern, albeit differing in sensitivity. The TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre, the total absorption cross section for Ge in both the fast and thermal neutrons region being some ten times greater than that of Al.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  13. Well-ordered mesoporous silica and bioactive glasses: promise for improved hemostasis
    Pourshahrestani S, Kadri NA, Zeimaran E, Towler MR
    Biomater Sci, 2018 Dec 18;7(1):31-50.
    PMID: 30374499 DOI: 10.1039/c8bm01041b
    Immediate control of uncontrolled bleeding and infection are essential for saving lives in both combat and civilian arenas. Inorganic well-ordered mesoporous silica and bioactive glasses have recently shown great promise for accelerating hemostasis and infection control. However, to date, there has been no comprehensive report assessing their specific mechanism of action in accelerating the hemostasis process and exerting an antibacterial effect. After providing a brief overview of the hemostasis process, this review presents a critical overview of the recently developed inorganic mesoporous silica and bioactive glass-based materials proposed for hemostatic clinical applications and specifically investigates their unique characteristics that render them applicable for hemostatic applications and preventing infections. This article also identifies promising new research directions that should be undertaken to ascertain the effectiveness of these materials for hemostatic applications.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  14. Ceria and titania incorporated silica based catalyst prepared from rice husk: adsorption and photocatalytic studies of methylene blue
    Adam F, Muniandy L, Thankappan R
    J Colloid Interface Sci, 2013 Sep 15;406:209-16.
    PMID: 23800370 DOI: 10.1016/j.jcis.2013.05.066
    Titania and ceria incorporated rice husk silica based catalyst was synthesized via sol-gel method using CTAB and glycerol as surface directing agents at room temperature and labeled as RHS-50Ti10Ce. The catalyst was used to study the adsorption and photodegradation of methylene blue (MB) under UV irradiation. The powder XRD pattern of RHS-50Ti10Ce was much broader (2θ=25-30°) than that of the parent RHS (2θ=22°). The catalyst exhibited type IV isotherm with H3 hysteresis loop, and the TEM images showed partially ordered pore arrangements. The TGA-DTG thermograms confirmed the complete removal of the templates after calcination at 500°C. RHS-50Ti10Ce exhibited excellent adsorption capability with more than 99% removal of MB from a 40 mg L(-1) solution in just 15 min. It also decolorized an 80 mg L(-1) MB solution under UV irradiation in 210 min, which was comparable with the commercialized pure anatase TiO2.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  15. Anion exchange silica monolith for capillary liquid chromatography
    Jaafar J, Watanabe Y, Ikegami T, Miyamoto K, Tanaka N
    Anal Bioanal Chem, 2008 Aug;391(7):2551-6.
    PMID: 18458888 DOI: 10.1007/s00216-008-2063-3
    An anion exchange monolithic silica capillary column was prepared by surface modification of a hybrid monolithic silica capillary column prepared from a mixture of tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS). The surface modification was carried out by on-column copolymerization of N-[3-(dimethylamino)propyl]acrylamide methyl chloride-quaternary salt (DMAPAA-Q) with 3-methacryloxypropyl moieties bonded as an anchor to the silica surface to form a strong anion exchange stationary phase. The columns were examined for their performance in liquid chromatography (LC) and capillary electrochromatography (CEC) separations of common anions. The ions were separated using 50 mM phosphate buffer at pH 6.6. Evaluation by LC produced an average of 30,000 theoretical plates (33 cm column length) for the inorganic anions and nucleotides. Evaluation by CEC, using the same buffer, produced enhanced chromatographic performance of up to ca. 90,000 theoretical plates and a theoretical plate height of ca. 4 mum. Although reduced efficiency was observed for inorganic anions that were retained a long time, the results of this study highlight the potential utility of the DMAPAA-Q stationary phase for anion separations.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  16. Conversion of rice husk ash to zeolite beta
    Prasetyoko D, Ramli Z, Endud S, Hamdan H, Sulikowski B
    Waste Manag, 2006;26(10):1173-9.
    PMID: 16274981
    White rice husk ash (RHA), an agriculture waste containing crystalline tridymite and alpha-cristobalite, was used as a silica source for zeolite Beta synthesis. The crystallization of zeolite Beta from RHA at 150 degrees C in the presence of tetraethylammonium hydroxide was monitored by XRD, FTIR and (29)Si MAS NMR techniques. It was found that zeolite Beta started to form after 12h and the complete crystallization of zeolite Beta phase was achieved after 2d. XRD, (29)Si MAS NMR and solid yield studies indicate that the transformation mechanism of silica present in RHA to zeolite Beta involves dissolution of the ash, formation of an amorphous aluminosilicate after 6h of crystallization, followed by dissolution in the mother liquor and final transformation to pure zeolite Beta crystals.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  17. Ab initio calculation of vibrational frequencies and Raman spectra of barium peroxide glass including comparison of tetrahedral BaO4 with GeO4 and SiO4
    Rosli AN, Zabidi NA, Kassim HA, Shrivastava KN
    Spectrochim Acta A Mol Biomol Spectrosc, 2011 Sep;79(5):1251-5.
    PMID: 21571582 DOI: 10.1016/j.saa.2011.04.051
    We have calculated the vibrational frequencies of clusters of atoms from the first principles by using the density-functional theory in the local density approximation (LDA). We are also able to calculate the electronic binding energy for all of the clusters of atoms from the optimized structure. We have made clusters of BanOm (n, m=1-6) and have determined the bond lengths, vibrational frequencies as well as intensities in each case. We find that the peroxide cluster BaO2 occurs with the O-O vibrational frequency of 836.3 cm(-1). We also find that a glass network occurs in the material which explains the vibrational frequency of 67 cm(-1). The calculated values agree with those measured from the Raman spectra of barium peroxide and Ba-B-oxide glass. We have calculated the vibrational frequencies of BaO4, GeO4 and SiO4 each in tetrahedral configuration and find that the vibrational frequencies in these systems depend on the inverse square root of the atomic mass.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  18. Role of silica-based porous cellulose nanocrystals in improving water absorption and mechanical properties
    Aziz T, Farid A, Haq F, Kiran M, Ullah N, Faisal S, et al.
    Environ Res, 2023 Apr 01;222:115253.
    PMID: 36702191 DOI: 10.1016/j.envres.2023.115253
    Epoxy resins are important thermosetting polymers. They are widely used in many applications i.e., adhesives, plastics, coatings and sealers. Epoxy molding compounds have attained dominance among common materials due to their excellent mechanical properties. The sol-gel simple method was applied to distinguish the impact on the colloidal time. The properties were obtained with silica-based fillers to enable their mechanical and thermal improvement. The work which we have done here on epoxy-based nanocomposites was successfully modified. The purpose of this research was to look into the effects of cellulose nanocrystals (CNCs) on various properties and applications. CNCs have recently attracted a lot of interest in a variety of industries due to their high aspect ratio, and low density which makes them perfect candidates. Adding different amounts of silica-based nanocomposites to the epoxy system. Analyzed with different techniques such as Fourier-transformed infrared spectroscope (FTIR), thermogravimetric analysis (TGA) and scanning electronic microscopic (SEM) to investigate the morphological properties of modified composites. The various %-age of silica composite was prepared in the epoxy system. The 20% of silica was shown greater enhancement and improvement. They show a better result than D-400 epoxy. Increasing the silica, the transparency of the films decreased, because clustering appears. This shows that the broad use of CNCs in environmental engineering applications is possible, particularly for surface modification, which was evaluated for qualities such as absorption and chemical resistant behavior.
    Matched MeSH terms: Silicon Dioxide/chemistry
  19. Catalyst free silica templated porous carbon nanoparticles from bio-waste materials
    Kumar A, Hegde G, Manaf SA, Ngaini Z, Sharma KV
    Chem Commun (Camb), 2014 Oct 28;50(84):12702-5.
    PMID: 25100105 DOI: 10.1039/c4cc04378b
    Porous Carbon Nanoparticles (PCNs) with well-developed microporosity were obtained from bio-waste oil palm leaves (OPL) using single step pyrolysis in nitrogen atmosphere at 500-600 °C in tube-furnace without any catalysis support. The key approach was using silica (SiO2) bodies of OPL as a template in the synthesis of microporous carbon nanoparticles with very small particle sizes of 35-85 nm and pore sizes between 1.9-2 nm.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  20. Modulation of implants PEEK to composite resin shear bond strength and surface roughness on pre-treatment with contemporary air abrasion techniques vs photodynamic therapy vs conventional diamond grit bur
    Qamar Z, Zeeshan T, Alqahtani WMS, Alanazi A, Khalid Aqeel Almejlad N, Ahmed Khan T, et al.
    Photodiagnosis Photodyn Ther, 2023 Sep;43:103689.
    PMID: 37414110 DOI: 10.1016/j.pdpdt.2023.103689
    AIM: The chief aim of the study was to determine/equate the surface roughness (SRa) and shear bond strength (BS) of pretreated PEEK discs with contemporary air abrasion techniques, photodynamic (PD) therapy by curcumin photosensitizer (PS) and conventional diamond grit straight fissure bur adhered to the composite resin discs.

    MATERIAL AND METHOD: Two hundred discs of PEEK were prepared of 6 mm × 2 mm × 10 mm dimension. The discs were randomly divided into five groups (n = 40) for treatment, Group I: treatment with deionized distilled water (control group); Group II: PD therapy using curcumin PS; Group III: discs treated and abraded with air-borne particles (ABP) silica (30 μm particle size) modified alumina (Al); Group IV: ABP of alumina (110 μm particle size); and Group V: The PEEK were finished with 600-μm grit size straight diamond cutting bur installed in high speed hand-piece. The surface profilometer was used to evaluate the values of surface roughness (SRa) of pretreated PEEK discs. The discs were luted and bonded to discs of composite resin. The bonded PEEK samples were placed in Universal testing machine to evaluate shear BS. The type of BS failure for PEEK discs pre-treated with five regimes respectively was evaluated under stereo-microscope. The data was statistically analyzed using one-way ANOVA and the comparisons between mean values of shear BS were evaluated by Tukey's test (ρ≤0.05).

    RESULTS: The PEEK samples pre-treated with diamond cutting straight fissure burs displayed statistically significant highest value of SRa values (3.258± 0.785 µm). Similarly, the shear BS was observed to be higher for the PEEK discs pre-treated with straight fissure bur (22.37±0.78 MPa). A comparable difference but not statistically significant difference was observed between PEEK discs pre-treated by curcumin PS and ABP-silica modified alumina (ρ ≥ 0.05).

    CONCLUSION: PEEK discs pre-treated with diamond grit straight fissure bur displayed highest values of SRa and shear BS. It was trailed by ABP-Al pre-treated discs; whereas the SRa and shear BS values for the discs pre-treated with ABP-silica modified Al and curcumin PS did not show competitive difference.

    Matched MeSH terms: Silicon Dioxide/chemistry
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