Displaying publications 61 - 80 of 85 in total

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  1. Influence of multi-walled carbon nanotubes on textural and adsorption characteristics of in situ synthesized mesostructured silica
    Karim AH, Jalil AA, Triwahyono S, Kamarudin NH, Ripin A
    J Colloid Interface Sci, 2014 May 1;421:93-102.
    PMID: 24594037 DOI: 10.1016/j.jcis.2014.01.039
    Carbon nanotubes-mesostructured silica nanoparticles (CNT-MSN) composites were prepared by a simple one step method with various loading of CNT. Their surface properties were characterized by XRD, N2 physisorption, TEM and FTIR, while the adsorption performance of the CNT-MSN composites were evaluated on the adsorption of methylene blue (MB) while varying the pH, adsorbent dosage, initial MB concentration, and temperature. The CNTs were found to improve the physicochemical properties of the MSN and led to an enhanced adsorptivity for MB. N2 physisorption measurements revealed the development of a bimodal pore structure that increased the pore size, pore volume and surface area. Accordingly, 0.05 g L(-1) CNT-MSN was able to adsorb 524 mg g(-1) (qm) of 60 mg L(-1) MB at pH 8 and 303 K. The equilibrium data were evaluated using the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models, with the Langmuir model affording the best fit to the adsorption data. The adsorption kinetics were best described by the pseudo-first order model. These results indicate the potential of CNT-MSN composites as effective new adsorbents for dye adsorption.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  2. Fulltext Comparative study of tributyltin adsorption onto mesoporous silica functionalized with calix[4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix[4]arene
    Alahmadi S, Mohamad S, Maah MJ
    Molecules, 2014 Apr 10;19(4):4524-47.
    PMID: 24727422 DOI: 10.3390/molecules19044524
    The adsorption of tributyltin (TBT), onto three mesoporous silica adsorbents functionalized with calix[4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix[4]arene (MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively) has been compared. Batch adsorption experiments were carried out and the effect of contact time, initial TBT concentration, pH and temperature were studied. The Koble-Corrigan isotherm was the most suitable for data fitting. Based on a Langmuir isotherm model, the maximum adsorption capacities were 12.1212, 16.4204 and 7.5757 mg/g for MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively. The larger uptake and stronger affinity of MCM-TDI-PC4 than MCM-TDI-C4 and MCM-TDI-C4S probably results from van der Waals interactions and the pore size distribution of MCM-TDI-PC4. Gibbs free energies for the three adsorption processes of TBT presented a negative value, reflecting that TBT/surface interactions are thermodynamic favorable and spontaneous. The interaction processes were accompanied by an increase of entropy value for MCM-TDI-C4 and MCM-TDI-C4S (43.7192 and 120.7609 J/mol K, respectively) and a decrease for MCM-TDI-PC4 (-37.4704 J/mol K). It is obviously observed that MCM-TDI-PC4 spontaneously adsorbs TBT driven mainly by enthalpy change, while MCM-TDI-C4 and MCM-TDI-C4S do so driven mainly by entropy changes.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  3. Fulltext An experimental study on pile spacing effects under lateral loading in sand
    Khari M, Kassim KA, Adnan A
    ScientificWorldJournal, 2013;2013:734292.
    PMID: 24453900 DOI: 10.1155/2013/734292
    Grouped and single pile behavior differs owing to the impacts of the pile-to-pile interaction. Ultimate lateral resistance and lateral subgrade modulus within a pile group are known as the key parameters in the soil-pile interaction phenomenon. In this study, a series of experimental investigation was carried out on single and group pile subjected to monotonic lateral loadings. Experimental investigations were conducted on twelve model pile groups of configurations 1 × 2, 1 × 3, 2 × 2, 3 × 3, and 3 × 2 for embedded length-to-diameter ratio l/d = 32 into loose and dense sand, spacing from 3 to 6 pile diameter, in parallel and series arrangement. The tests were performed in dry sand from Johor Bahru, Malaysia. To reconstruct the sand samples, the new designed apparatus, Mobile Pluviator, was adopted. The ultimate lateral load is increased 53% in increasing of s/d from 3 to 6 owing to effects of sand relative density. An increasing of the number of piles in-group decreases the group efficiency owing to the increasing of overlapped stress zones and active wedges. A ratio of s/d more than 6d is large enough to eliminate the pile-to-pile interaction and the group effects. It may be more in the loose sand.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  4. 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*
  5. Extraction of phenanthrene and fluoranthene from contaminated sand using palm kernel and soybean oils
    Von Lau E, Gan S, Ng HK
    J Environ Manage, 2012 Sep 30;107:124-30.
    PMID: 22595079 DOI: 10.1016/j.jenvman.2012.04.029
    Experimental extraction tests are conducted to investigate feasibility of saturated palm kernel oil (PKO) and unsaturated soybean oil (SO) to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated sand. The extraction rates and efficiencies for lowly contaminated (LC) and highly contaminated (HC) sands at temperatures of 30 °C and 70 °C are evaluated using empirical first order kinetic dissolution models. In LC sand, the extraction is dominated by the diffusion of PAHs adsorbed onto particle surfaces and the direct dissolution of PAH phase. In HC sand, a rapid diffusion of PAHs adsorbed onto particle surfaces and a direct dissolution of PAH phase occur followed by a slower diffusion of PAHs entrapped within the pores and micropores. Larger diffusion resistance during HC sand extractions results in an average 10.8% reduction in extraction efficiencies compared to LC sand. Increased temperature generally increases the mass transfer rates and extraction efficiencies. Additionally, the physicochemical properties of both oils and PAHs also determine the extent of PAH extraction into oil.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  6. Amino modified mesostructured silica nanoparticles for efficient adsorption of methylene blue
    Karim AH, Jalil AA, Triwahyono S, Sidik SM, Kamarudin NH, Jusoh R, et al.
    J Colloid Interface Sci, 2012 Nov 15;386(1):307-14.
    PMID: 22889626 DOI: 10.1016/j.jcis.2012.07.043
    In this work, mesostructured silica nanoparticles (MSN(AP)) with high adsorptivity were prepared by a modification with 3-aminopropyl triethoxysilane (APTES) as a pore expander. The performance of the MSN(AP) was tested by the adsorption of MB in a batch system under varying pH (2-11), adsorbent dosage (0.1-0.5 g L(-1)), and initial MB concentration (5-60 mg L(-1)). The best conditions were achieved at pH 7 when using 0.1 g L(-1) MSN(AP) and 60 mg L(-1)MB to give a maximum monolayer adsorption capacity of 500.1 mg g(-1) at 303 K. The equilibrium data were evaluated using the Langmuir, Freundlich, Temkin, and Harkins-Jura isotherms and fit well to the Freundlich isotherm model. The adsorption kinetics was best described by the pseudo-second order model. The results indicate the potential for a new use of mesostructured materials as an effective adsorbent for MB.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  7. 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*
  8. Characteristics of supported nano-TiO2/ZSM-5/silica gel (SNTZS): photocatalytic degradation of phenol
    Zainudin NF, Abdullah AZ, Mohamed AR
    J Hazard Mater, 2010 Feb 15;174(1-3):299-306.
    PMID: 19818556 DOI: 10.1016/j.jhazmat.2009.09.051
    Photocatalytic degradation of phenol was investigated using the supported nano-TiO(2)/ZSM-5/silica gel (SNTZS) as a photocatalyst in a batch reactor. The prepared photocatalyst was characterized using XRD, TEM, FT-IR and BET surface area analysis. The synthesized photocatalyst composition was developed using nano-TiO(2) as the photoactive component and zeolite (ZSM-5) as the adsorbents, all supported on silica gel using colloidal silica gel binder. The optimum formulation of SNTZS catalyst was observed to be (nano-TiO(2):ZSM-5:silica gel:colloidal silica gel=1:0.6:0.6:1) which giving about 90% degradation of 50mg/L phenol solution in 180 min. The SNTZS exhibited higher photocatalytic activity than that of the commercial Degussa P25 which only gave 67% degradation. Its high photocatalytic activity was due to its large specific surface area (275.7 m(2)/g), small particle size (8.1 nm), high crystalline quality of the synthesized catalyst and low electron-hole pairs recombination rate as ZSM-5 adsorbent was used. The SNTZS photocatalyst synthesized in this study also has been proven to have an excellent adhesion and reusability.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  9. Ordered mesoporous silica (OMS) as an adsorbent and membrane for separation of carbon dioxide (CO2)
    Chew TL, Ahmad AL, Bhatia S
    Adv Colloid Interface Sci, 2010 Jan 15;153(1-2):43-57.
    PMID: 20060956 DOI: 10.1016/j.cis.2009.12.001
    Separation of carbon dioxide (CO(2)) from gaseous mixture is an important issue for the removal of CO(2) in natural gas processing and power plants. The ordered mesoporous silicas (OMS) with uniform pore structure and high density of silanol groups, have attracted the interest of researchers for separation of carbon dioxide (CO(2)) using adsorption process. These mesoporous silicas after functionalization with amino groups have been studied for the removal of CO(2). The potential of functionalized ordered mesoporous silica membrane for separation of CO(2) is also recognized. The present paper reviews the synthesis of mesoporous silicas and important issues related to the development of mesoporous silicas. Recent studies on the CO(2) separation using ordered mesoporous silicas (OMS) as adsorbent and membrane are highlighted. The future prospectives of mesoporous silica membrane for CO(2) adsorption and separation are also presented and discussed.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  10. Fulltext Synthesis and characterization of mesoporous silica functionalized with calix[4]arene derivatives
    Alahmadi SM, Mohamad S, Maah MJ
    Int J Mol Sci, 2012;13(10):13726-36.
    PMID: 23202977 DOI: 10.3390/ijms131013726
    This work reports a new method to covalently attach calix[4]arene derivatives onto MCM-41, using a diisocyanate as a linker. The modified mesoporous silicates were characterized by fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by X-ray diffraction and nitrogen adsorption analysis.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  11. 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*
  12. Fulltext Experimental evaluation of oil recovery mechanism using a variety of surface-modified silica nanoparticles: Role of in-situ surface-modification in oil-wet system
    Adil M, Mohd Zaid H, Raza F, Agam MA
    PLoS One, 2020;15(7):e0236837.
    PMID: 32730369 DOI: 10.1371/journal.pone.0236837
    Recent developments propose renewed use of surface-modified nanoparticles (NPs) for enhanced oil recovery (EOR) due to improved stability and reduced porous media retention. The enhanced surface properties render the nanoparticles more suitable compared to bare nanoparticles, for increasing the displacement efficiency of waterflooding. However, the EOR mechanisms using NPs are still not well established. This work investigates the effect of in-situ surface-modified silica nanoparticles (SiO2 NPs) on interfacial tension (IFT) and wettability behavior as a prevailing oil recovery mechanism. For this purpose, the nanoparticles have been synthesized via a one-step sol-gel method using surface-modification agents, including Triton X-100 (non-ionic surfactant) and polyethylene glycol (polymer), and characterized using various techniques. These results exhibit the well-defined spherical particles, particularly in the presence of Triton X-100 (TX-100), with particle diameter between 13 to 27 nm. To this end, SiO2 nanofluids were formed by dispersing nanoparticles (0.05 wt.%, 0.075 wt.%, 0.1 wt.%, and 0.2 wt.%) in 3 wt.% NaCl to study the impact of surface functionalization on the stability of the nanoparticle suspension. The optimal stability conditions were obtained at 0.1 wt.% SiO2 NPs at a basic pH of 10 and 9.5 for TX-100/ SiO2 and PEG/SiO nanofluids, respectively. Finally, the surface-treated SiO2 nanoparticles were found to change the wettability of treated (oil-wet) surface into water-wet by altering the contact angle from 130° to 78° (in case of TX-100/SiO2) measured against glass surface representing carbonate reservoir rock. IFT results also reveal that the surfactant treatment greatly reduced the oil-water IFT by 30%, compared to other applied NPs. These experimental results suggest that the use of surface-modified SiO2 nanoparticles could facilitate the displacement efficiency by reducing IFT and altering the wettability of carbonate reservoir towards water-wet, which is attributed to more homogeneity and better dispersion of surface-treated silica NPs compared to bare-silica NPs.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  13. Radioluminescence of cylindrical and flat Ge-doped silica optical fibers for real-time dosimetry applications
    Oresegun A, Tarif ZH, Ghassan L, Zin H, Abdul-Rashid HA, Bradley DA
    Appl Radiat Isot, 2021 Oct;176:109812.
    PMID: 34166948 DOI: 10.1016/j.apradiso.2021.109812
    Investigation has been made of the radioluminescence dose response of Ge-doped silica flat and cylindrical fibers subjected to 6 and 10 MV photon beams. The fibers have been custom fabricated, obtaining Ge dopant concentrations of 6 and 10 mol%, subsequently cut into 20 mm lengths. Each sample has been exposed under a set of similar conditions, with use made of a fixed field size and source to surface distance (SSD). Investigation of dosimetric performance has involved radioluminescence linearity, dose-rate dependence, energy dependence, and reproducibility. Mass for mass, the 6 mol% Ge-doped samples provided the greater radioluminescence yield, with both flat and cylindrical fibers responding linearly to the absorbed dose. Further found has been that the cylindrical fibers provided a yield some 38% greater than that of the flat fibers. At 6 MV, the cylindrical fibers were also found to exhibit repeatability variation of <1%, superior to that of the flat fibers, offering strong potential for use in real-time dosimetry applications.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  14. Ethyl-4-(aryl)-6-methyl-2-(oxo/thio)-3,4-dihydro-1H-pyrimidine-5-carboxylates: Silica supported bismuth(III)triflate catalyzed synthesis and antioxidant activity
    Gajjala RR, Chinta RR, Gopireddy VSR, Poola S, Balam SK, Chintha V, et al.
    Bioorg Chem, 2022 Dec;129:106205.
    PMID: 36265354 DOI: 10.1016/j.bioorg.2022.106205
    Novel ethyl-4-(aryl)-6-methyl-2-(oxo/thio)-3,4-dihydro-1H-pyrimidine-5-carboxylates were synthesized from one-pot, three-component Biginelli reaction of aryl aldehydes, ethyl acetoacetate and urea/ thiourea by catalytic action of silica supported Bismuth(III) triflate, a Lewis acid. All the synthesized compounds were structurally characterized by spectral (IR, 1H NMR & 13C NMR spectroscopic and Mass spectrometric) and elemental (C, H & N) analyses. The present protocol has deserved novel as, formed the products in high yields with short reaction times, involved eco-friendly methodology and reusable heterogeneous Lewis acid catalyst. The title compounds were screened for in vitro DPPH free radical scavenging antioxidant activity and identified 4i, 4j, 4h & 4f as potential antioxidants. The obtained in vitro results were correlated with molecular docking, ADMET, QSAR, Bioactivity & toxicity risk studies and molecular finger print properties and found that in silico binding affinities were identified in good correlation with in vitro antioxidant activity and studied the structure activity relationship. The molecular docking study has disclosed strong hydrogen bonding interactions of title compounds with aspartic acid (ASP197) aminoacid residue of 2HCK, a complex enzyme of haematopoietic cell kinase and quercetin. Results of toxicology study evaluated for potential risks of compounds have revealed title compounds as safer drugs. In ultimate the study has established ligand's antioxidant potentiality as they effectively binds with ASP197 amino acid of Chain A hence confirms the inhibition of growth of reactive oxygen species in vivo. In addition, the title compounds have been identified as potential blood-brain barrier penetrable entities and efficient central nervous system (CNS) active neuro-protective antioxidant agents.
    Matched MeSH terms: Silicon Dioxide/chemistry
  15. Progress in ultrasonic oil-contaminated sand cleaning: a fundamental review
    Mat-Shayuti MS, Tuan Ya TMYS, Abdullah MZ, Megat Khamaruddin PNF, Othman NH
    Environ Sci Pollut Res Int, 2019 Sep;26(26):26419-26438.
    PMID: 31327143 DOI: 10.1007/s11356-019-05954-w
    Steady efforts in using ultrasonic energy to treat oil-contaminated sand started in the early 2000s until today, although pilot studies on the area can be traced to even earlier dates. Owing to the unique characteristics of the acoustic means, the separation of oil from sand has been showing good results in laboratories. This review provides the compilation of researches and insights into the mechanism of separation thus far. Related topics in the areas of oil-contaminated sand characterizations, fundamental ultrasonic cleaning, and cavitation effects are also addressed. Nevertheless, many of the documented works are only at laboratory or pilot-scale level, and the comprehensive interaction between ultrasonic parameters towards cleaning efficiencies may not have been fully unveiled. Gaps and opportunities are also presented at the end of this article.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  16. Fulltext An intriguing approach toward antibacterial activity of green synthesized Rutin-templated mesoporous silica nanoparticles decorated with nanosilver
    Abbasi M, Gholizadeh R, Kasaee SR, Vaez A, Chelliapan S, Fadhil Al-Qaim F, et al.
    Sci Rep, 2023 Apr 12;13(1):5987.
    PMID: 37046068 DOI: 10.1038/s41598-023-33095-1
    In recent years, mesoporous silica nanoparticles (MSNs) have been applied in various biomedicine fields like bioimaging, drug delivery, and antibacterial alternatives. MSNs could be manufactured through green synthetic methods as environmentally friendly and sustainable synthesis approaches, to improve physiochemical characteristics for biomedical applications. In the present research, we used Rutin (Ru) extract, a biocompatible flavonoid, as the reducing agent and nonsurfactant template for the green synthesis of Ag-decorated MSNs. Transmission electron microscopy (TEM), zeta-potential, x-ray powder diffraction (XRD), fourier transform infrared (FTIR) spectroscopy analysis, scanning electron microscopy (SEM), brunauer-emmett-teller (BET) analysis, and energy-dispersive system (EDS) spectroscopy were used to evaluate the Ag-decorated MSNs physical characteristics. The antimicrobial properties were evaluated against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and also different types of candida. The cytotoxicity test was performed by using the MTT assay. Based on the findings, the significant antimicrobial efficacy of Ru-Ag-decorated MSNs against both gram positive and gram negative bacteria and different types of fungi was detected as well as acceptable safety and low cytotoxicity even at lower concentrations. Our results have given a straightforward and cost-effective method for fabricating biodegradable Ag-decorated MSNs. The applications of these MSNs in the domains of biomedicine appear to be promising.
    Matched MeSH terms: Silicon Dioxide/chemistry
  17. 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
  18. Fulltext Effects of using silica fume and polycarboxylate-type superplasticizer on physical properties of cementitious grout mixtures for semiflexible pavement surfacing
    Koting S, Karim MR, Mahmud H, Mashaan NS, Ibrahim MR, Katman H, et al.
    ScientificWorldJournal, 2014;2014:596364.
    PMID: 24526911 DOI: 10.1155/2014/596364
    Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-sample t-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout.
    Matched MeSH terms: Silicon Dioxide/chemistry*
  19. Fulltext How Key Alterations of Mesoporous Silica Nanoparticles Affect Anti-Lung Cancer Therapy? A Comprehensive Review of the Literature
    Budiman A, Rusdin A, Subra L, Aulifa DL
    Int J Nanomedicine, 2023;18:5473-5493.
    PMID: 37791322 DOI: 10.2147/IJN.S426120
    In 2020, there were 2.21 million new instances of lung cancer, making it the top cause of mortality globally, responsible for close to 10 million deaths. The physicochemical problems of chemotherapy drugs are the primary challenge that now causes a drug's low effectiveness. Solubility is a physicochemical factor that has a significant impact on a drug's biopharmaceutical properties, starting with the rate at which it dissolves and extending through how well it is absorbed and bioavailable. One of the most well-known methods for addressing a drug's solubility is mesoporous silica, which has undergone excellent development due to the conjugation of polymers and ligands that increase its effectiveness. However, there are still very few papers addressing the success of this discovery, particularly those addressing its molecular pharmaceutics and mechanism. Our study's objectives were to explore and summarize the effects of targeting mediator on drug development using mesoporous silica with and without functionalized polymer. We specifically focused on highlighting the molecular pharmaceutics and mechanism in this study's innovative findings. Journals from the Scopus, PubMed, and Google Scholar databases that were released during the last ten years were used to compile this review. According to inclusion and exclusion standards adjusted. This improved approach produced very impressive results, a very significant change in the characteristics of mesoporous silica that can affect effectiveness. Mesoporous silica approaches have the capacity to greatly enhance a drug's physicochemical issues, boost therapeutic efficacy, and acquire superb features.
    Matched MeSH terms: Silicon Dioxide/chemistry
  20. Vanadia as an electron-hole recombination inhibitor on fibrous silica-titania for selective hole oxidation of ciprofloxacin and Congo red photodegradation
    Hassan NS, Jalil AA, Fei ICM, Razak MTA, Khusnun NF, Bahari MB, et al.
    Chemosphere, 2023 Oct;338:139502.
    PMID: 37453521 DOI: 10.1016/j.chemosphere.2023.139502
    Vanadia (V2O5)-incorporated fibrous silica-titania (V/FST) catalysts, which were successfully synthesized using a hydrothermal method followed by the impregnation of V2O5. The catalysts were then characterized using numerous techniques, including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption analyses, ultraviolet-visible diffuse reflectance spectroscopy, Fourier-transform infrared, X-ray photoelectron spectroscopy, and photoluminescence (PL) analyses. The study found that varying the amount of V2O5 (1-10 wt%) had a significant impact on the physicochemical properties of the FST, which in turn improved the photodegradation efficiency of two organic compounds, ciprofloxacin (CIP) and congo red (CR). 5V/FST demonstrated the best performance in degrading 10 mg L-1 of CIP (83%) and CR (100%) at pH 3 using 0.375 g L-1 catalyst under visible light irradiation within 180 min. The highest photoactivity of 5V/FST is mainly due to higher crystallinity and the highest number of V2O5-FST interactions. Furthermore, as demonstrated by PL analysis, the 5V/FST catalyst has the most significant impact on interfacial charge transfer and reduces electron-hole recombination. The photodegradation of both contaminants follows the Langmuir-Hinshelwood pseudo-first-order model, according to the kinetic study. The scavenger investigation demonstrated that hydroxyl radicals and holes dominated species in the system, indicating that the catalyst effectively generated reactive species for pollutant degradation. A possible mechanism was also identified for FST and 5V/FST. Interestingly, V2O5 acts as an electron-hole recombination inhibitor on FST for selective hole oxidation of ciprofloxacin and congo red photodegradation. Finally, the degradation efficiency of the catalyst remained relatively stable even after five cyclic experiments, indicating its potential for long-term use in environmental remediation.
    Matched MeSH terms: Silicon Dioxide/chemistry
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