Displaying publications 1 - 20 of 31 in total

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  1. Wee JL, Chan YS, Law MC
    ACS Appl Bio Mater, 2023 Nov 20;6(11):4972-4987.
    PMID: 37910790 DOI: 10.1021/acsabm.3c00515
    The use of nanometal oxides in nanoagronomy has garnered considerable attention due to their excellent antifungal and plant growth promotion properties. Hybrid nanometal oxides, which combine the strengths of individual nanomaterials, have emerged as a promising class of materials. In this study, nanomagnesium oxide (n-MgO) and hybrid magnetic nanomagnesium oxide (m/n-MgO) were successfully synthesized via the ultrasound-mediated sol-gel method. Characterization results, including TGA, XRD, VSM, and FTIR, confirmed the successful synthesis of m/n-MgO. Both n-MgO and m/n-MgO underwent antifungal assays and plant growth promotion ability studies, benchmarked against the conventional fungicide-copper oxychloride. This study bridges a significant gap by simultaneously reporting the antifungal properties of both n-MgO and m/n-MgO and their impact on plant growth. The disc diffusion assay suggested that the antifungal activity of n-MgO and m/n-MgO against F. oxysporum was inversely related to the particle size. Notably, n-MgO exhibited superior antifungal performance (lower minimum inhibitory concentration (MIC)) and sustained efficacy compared with m/n-MgO, owing to distinct antifungal mechanisms. Nanorod-shaped MgO, with a smaller size (8.24 ± 5.61 nm) and higher aspect ratio, allowed them to penetrate the fungal cell wall and cause intercellular damage. In contrast, cubical m/n-MgO, with a larger size (20.95 ± 9.99 nm) and lower aspect ratio, accumulate on the fungal cell wall surface, disrupting the wall integrity, albeit less effectively against F. oxysporum. Moreover, in plant growth promotion studies, m/n-MgO-treated samples exhibited a 15.7% stronger promotion effect compared to n-MgO at their respective MICs. In addition, both n-MgO and m/n-MgO outperformed copper oxychloride in terms of antifungal and plant growth promoting activities. Thus, m/n-MgO presents a promising alternative to conventional copper-based fungicides, offering dual functionality as a fungicide and plant growth promoter, while the study also delves into the antifungal mechanisms at the intracellular level, enhancing its novelty.
    Matched MeSH terms: Magnesium Oxide/pharmacology
  2. Danagody B, Bose N, Rajappan K, Iqbal A, Ramanujam GM, Anilkumar AK
    ACS Biomater Sci Eng, 2024 Jan 08;10(1):468-481.
    PMID: 38078836 DOI: 10.1021/acsbiomaterials.3c00892
    Developing biomaterial scaffolds using tissue engineering with physical and chemical surface modification processes can improve the bioactivity and biocompatibility of the materials. The appropriate substrate and site for cell attachment are crucial in cell behavior and biological activities. Therefore, the study aims to develop a conventional electrospun nanofibrous biomaterial using reproducible surface topography, which offers beneficial effects on the cell activities of bone cells. The bioactive MgO/gC3N4 was incorporated on PAN/PEG and fabricated into a nanofibrous membrane using electrospinning. The nanocomposite uniformly distributed on the PAN/PEG nanofiber helps to increase the number of induced pores and reduce the hydrophobicity of PAN. The physiochemical characterization of prepared nanoparticles and nanofibers was carried out using FTIR, X-ray diffraction (XRD), thermogravimetry analysis (TGA), X-ray photoelectron spectroscopy (XPS), and water contact angle measurements. SEM and TEM analyses examined the nanofibrous morphology and the structure of MgO/gC3N4. In vitro studies such as on ALP activity demonstrated the membrane's ability to regenerate new bone and healing capacity. Furthermore, alizarin red staining showed the increasing ability of the cell-cell interaction and calcium content for tissue regeneration. The cytotoxicity of the prepared membrane was about 97.09% of live THP-1 cells on the surface of the MgO/gC3N4@PAN/PEG membrane evaluated using MTT dye staining. The soil burial degradation analysis exhibited that the maximum degradation occurs on the 45th day because of microbial activity. In vitro PBS degradation was observed on the 15th day after the bulk hydrolysis mechanism. Hence, on the basis of the study outcomes, we affirm that the MgO/gC3N4@PAN/PEG nanofibrous membrane can act as a potential bone regenerative substrate.
    Matched MeSH terms: Magnesium Oxide/pharmacology
  3. Jeevanandam J, Chan YS, Danquah MK, Law MC
    Appl Biochem Biotechnol, 2020 Apr;190(4):1385-1410.
    PMID: 31776944 DOI: 10.1007/s12010-019-03166-z
    Insulin resistance is one of the major factors that leads to type 2 diabetes. Although insulin therapies have been shown to overcome insulin resistance, overweight and hypoglycemia are still observed in most cases. The disadvantages of insulin therapies have driven the interest in developing novel curative agents with enhanced insulin resistance reversibility. Magnesium deficiency has also been recognized as a common problem which leads to insulin resistance in both type 1 and 2 diabetes. Oxide nanoparticles demonstrate highly tunable physicochemical properties that can be exploited by engineers to develop unique oxide nanoparticles for tailored applications. Magnesium supplements for diabetic cells have been reported to increase the insulin resistance reversibility. Hence, it is hypothesized that magnesium oxide (MgO) nanoparticles could be molecularly engineered to offer enhanced therapeutic efficacy in reversing insulin resistance. In the present work, morphologically different MgO nanoparticles were synthesized and evaluated for biophysical characteristics, biocompatibility, cytotoxicity, and insulin resistance reversibility. MTT assay revealed that hexagonally shaped MgO nanoparticles are less toxic to 3T3-L1 adipose cells (diabetic) compared with spherically and rod-shaped MgO nanoparticles. MTT assays using VERO cells (normal, non-diabetic) showed that 400 μg/ml of hexagonal MgO nanoparticles were less toxic to both diabetic and non-diabetic cells. DNS glucose assay and western blot showed that hexagonally shaped MgO nanoparticles had reversed 29.5% of insulin resistance whilst fluorescence microscopy studies indicated that the insulin resistance reversal is due to the activation of intracellular enzymes. The probable mechanism for MgO nanoparticles to induce cytotoxic effect and insulin resistance reversal is discussed.
    Matched MeSH terms: Magnesium Oxide/chemistry*
  4. Abdullah H, Pearson GJ
    Asian J Aesthet Dent, 1993 Jul;1(2):91-4.
    PMID: 7921802
    The effect of temperature change on the working and setting time of a glass ionomer luting cement and a resin luting cement was measured using the oscillating rheometer. The time taken for each cement to set was calculated from the chart recordings. It was observed that as the temperature increased, the working and setting time of both materials decreased. However, the reduction was much more marked for the dual curing resin cement.
    Matched MeSH terms: Magnesium Oxide/chemistry*
  5. Nik Nur Syafika Pahri, Nur Huda Syazwani Jafri, Husna Ahmad Tajuddin, Yusilawati Ahmad Nor
    MyJurnal
    Effective treatment of wastewater is crucial in order to achieve a sustainable development. For instance, highly efficient treatment processes with low capital requirements are the major prerequisite for implementation of the advanced wastewater treatment operations. Among various available treatment methods, the application of coagulation-flocculation process by using natural coagulant; chitosan has vast advantages such as low operating cost, environmental friendly and highly effective in the wastewater treatment operations. The application of nanotechnology in numerous treatment techniques are considered as the most significant advances in water and wastewater treatment practices. The utilization of magnesium oxide (MgO) as nano-adsorbent has recently gained attention as a potential treatment method in water remediation particularly for treating effluents with high amount of organic dyes and heavy metals due to its high treatment efficiency, low cost, versatility and environment compatibility. The purpose of this study was to determine the effectiveness of coagulation-flocculation process when using novel coagulant in which MgO coated with chitosan by investigating the percentage removal of several significant parameters which were turbidity, chemical oxygen demand (COD) and suspended solid. The removal efficiencies were determined throughout a series of experiments carried out using a standard jar test procedure in which three different coagulants; chitosan, MgO coated with chitosan and MgO were tested on water samples taken from Sg. Pusu. In addition, a set of experiments was designed using response surface methodology (RSM) in order to optimize adsorption of chitosan into MgO. The experiments were conducted at various concentrations of chitosan (10-30 mg/ml) and selected MgO dosage ranges (10-30 mg). From the obtained results, it was found that chitosan-MgO coagulant has good removal efficiencies of turbidity, chemical oxygen demand (COD) and suspended solids at 92%, 91%, and 98% respectively from the optimization of adsorption of chitosan-MgO. The MgO coated with chitosan is the best coagulant in this study compared to chitosan and MgO alone because of the ability of treating the river water with up to 90 % removal for all the main parameters. The results showed that coagulation-flocculation is effective as a treatment for treating river water.
    Matched MeSH terms: Magnesium Oxide
  6. Al-Fahdawi MQ, Al-Doghachi FAJ, Abdullah QK, Hammad RT, Rasedee A, Ibrahim WN, et al.
    Biomed Pharmacother, 2021 Jun;138:111483.
    PMID: 33744756 DOI: 10.1016/j.biopha.2021.111483
    The aim of this study was to prepare, characterize, and determine the in vitro anticancer effects of platinum-doped magnesia (Pt/MgO) nanoparticles. The chemical compositions, functional groups, and size of nanoparticles were determined using X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. Pt/MgO nanoparticles were cuboid and in the nanosize range of 30-50 nm. The cytotoxicity of Pt/MgO nanoparticles was determined via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on the human lung and colonic cancer cells (A549 and HT29 respectively) and normal human lung and colonic fibroblasts cells (MRC-5 and CCD-18Co repectively). The Pt/MgO nanoparticles were relatively innocuous to normal cells. Pt/MgO nanoparticles downregulated Bcl-2 and upregulated Bax and p53 tumor suppressor proteins in the cancer cells. Pt/MgO nanoparticles also induced production of reactive oxygen species, decreased cellular glutathione level, and increased lipid peroxidation. Thus, the anticancer effects of Pt/MgO nanoparticles were attributed to the induction of oxidative stress and apoptosis. The study showed the potential of Pt/MgO nanoparticles as an anti-cancer compound.
    Matched MeSH terms: Magnesium Oxide/toxicity*
  7. Rahman NA, Olutoye MA, Hameed BH
    Bioresour Technol, 2011 Oct;102(20):9749-54.
    PMID: 21855332 DOI: 10.1016/j.biortech.2011.07.023
    The potential of Mg(x)Co(2-)(x)O(2) as heterogeneous reusable catalyst in transesterification of palm oil to methyl ester was investigated. The catalyst was prepared via co-precipitation of the metal hydroxides at different Mg-Co ratios. Mg(1.7)Co(0.3)O(2) catalyst was more active than Mg(0.3)Co(1.7)O(2) in the transesterification of palm oil with methanol. The catalysts calcined at temperature 300 °C for 4 h resulted in highly active oxides and the highest transesterification of 90% was achieved at methanol/oil molar ratio of 9:1, catalyst loading of 5.00 wt.%, reaction temperature of 150 °C and reaction time of 2 h. The catalyst could easily be removed from reaction mixture, but showed 50% decrease in activity when reused due to leaching of active sites.
    Matched MeSH terms: Magnesium Oxide/chemistry*
  8. Fan MS, Abdullah AZ, Bhatia S
    ChemSusChem, 2011 Nov 18;4(11):1643-53.
    PMID: 22191096
    A series of bimetallic catalysts containing nickel supported over MgO-ZrO2 were tested for activity in the dry reforming of carbon dioxide. A nickel-cobalt bimetallic catalyst gave the best performance in terms of conversion and coke resistance from a range of Ni-X bimetallic catalysts, X=Ca, K, Ba, La, and Ce. The nitrogen-adsorption and hydrogen-chemisorption studies showed the Ni-Co bimetallic supported catalyst to have good surface area with high metal dispersion. This contributed to the high catalytic activity, in terms of conversion activity and stability of the catalyst, at an equimolar methane/carbon dioxide feed ratio. The kinetics of methane dry reforming are studied in a fixed-bed reactor over an Ni-Co bimetallic catalyst in the temperature range 700-800 °C by varying the partial pressures of CH4 and CO2. The experimental data were analyzed based on the proposed reaction mechanism using the Langmuir-Hinshelwood kinetic model. The activation energies for methane and carbon dioxide consumption were estimated at 52.9 and 48.1 kJ mol(-1), respectively. The lower value of CO2 activation energy compared to the activation energy of CH4 indicated a higher reaction rate of CO2, which owes to the strong basicity of nanocrystalline support, MgO-ZrO2.
    Matched MeSH terms: Magnesium Oxide/chemistry
  9. Moogi S, Jang SH, Rhee GH, Ko CH, Choi YJ, Lee SH, et al.
    Chemosphere, 2022 Jan;287(Pt 2):132224.
    PMID: 34826918 DOI: 10.1016/j.chemosphere.2021.132224
    Food waste, a renewable resource, was converted to H2-rich gas via a catalytic steam gasification process. The effects of basic oxides (MgO, CaO, and SrO) with 10 wt% Ni/Al2O3 on the gasification properties of food waste were investigated using a U-shaped gasifier. All catalysts prepared by the precipitation method were analyzed by X-ray diffraction, H2-temperature-programmed reduction, NH3-temperature-programmed desorption, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The Ni/Al2O3 catalyst was reduced incompletely, and low nickel concentrations were detected on the surface of the alumina. The basic oxides minimized the number of acid sites and suppressed the formation of nickel-aluminate (NiAlxOy) phase in catalyst. In addition, the basic oxides shifted nickel-aluminate reduction reaction to lower temperatures. It resulted in enhancing nickel concentration on the catalyst surface and increasing gas yield and hydrogen selectivity. The low gas yield of the Ni/Al2O3 catalyst was attributed to the low nickel concentration on the surface. The maximum gas yield (66.0 wt%) and hydrogen selectivity (63.8 vol%) of the 10 wt% SrO- 10 wt% Ni/Al2O3 catalyst correlated with the highly dispersed nickel on the surface and low acidity. Furthermore, coke deposition during steam gasification varied with the surface acidity of the catalysts and less coke was formed on 10 wt% SrO- 10 wt% Ni/Al2O3 due to efficient tar cracking. This study showed that the steam gasification efficiency of the Ni/Al2O3 catalyst could be improved significantly by the addition of SrO.
    Matched MeSH terms: Magnesium Oxide
  10. Taoufik N, Janani FZ, Khiar H, Sadiq M, Abdennouri M, Sillanpää M, et al.
    Environ Sci Pollut Res Int, 2023 Feb;30(9):23938-23964.
    PMID: 36329247 DOI: 10.1007/s11356-022-23690-6
    In the present work, we prepared MgO-La2O3-mixed-metal oxides (MMO) as efficient photocatalysts for degradation of organic pollutants. First, a series of MgAl-%La-CO3-layered double hydroxide (LDH) precursors with different contents of La (5, 10, and 20 wt%) were synthesized by the co-precipitation process and then calcined at 600 °C. The prepared materials were characterized by XRD, SEM-EDX, FTIR, TGA, ICP, and UV-vis diffuse reflectance spectroscopy. XRD indicated that MgO, La2O3, and MgAl2O4 phases were found to coexist in the calcined materials. Also, XRD confirms the orthorhombic-tetragonal phases of MgO-La2O3. The samples exhibited a small band gap of 3.0-3.22 eV based on DRS. The photocatalytic activity of the catalysts was assessed for the degradation of two dyes, namely, tartrazine (TZ) and patent blue (PB) as model organic pollutants in aqueous mediums under UV-visible light. Detailed photocatalytic tests that focused on the impacts of dopant amount of La, catalyst dose, initial pH of the solution, irradiation time, dye concentration, and reuse were carried out and discussed in this research. The experimental findings reveal that the highest photocatalytic activity was achieved with the MgO-La2O3-10% MMO with photocatalysts with a degradation efficiency of 97.4% and 93.87% for TZ and PB, respectively, within 150 min of irradiation. The addition of La to the sample was responsible for its highest photocatalytic activity. Response surface methodology (RSM) and gradient boosting regressor (GBR), as artificial intelligence techniques, were employed to assess individual and interactive influences of initial dye concentration, catalyst dose, initial pH, and irradiation time on the degradation performance. The GBR technique predicts the degradation efficiency results with R2 = 0.98 for both TZ and PB. Moreover, ANOVA analysis employing CCD-RSM reveals a high agreement between the quadratic model predictions and the experimental results for TZ and PB (R2 = 0.9327 and Adj-R2 = 0.8699, R2 = 0.9574 and Adj-R2 = 0.8704, respectively). Optimization outcomes indicated that maximum degradation efficiency was attained under the following optimum conditions: catalyst dose 0.3 g/L, initial dye concentration 20 mg/L, pH 4, and reaction time 150 min. On the whole, this study confirms that the proposed artificial intelligence (AI) techniques constituted reliable and robust computer techniques for monitoring and modeling the photodegradation of organic pollutants from aqueous mediums by MgO-La2O3-MMO heterostructure catalysts.
    Matched MeSH terms: Magnesium Oxide*
  11. Hezaveh H, Muhamad II
    Int J Biol Macromol, 2012 Jun 1;50(5):1334-40.
    PMID: 22484730 DOI: 10.1016/j.ijbiomac.2012.03.017
    In this article, modified κ-carrageenan hydrogel nanocomposites were synthesized to increase the release ability of carrageenan hydrogels under gastrointestinal conditions. The effect of MgO nanoparticle loading in a model drug (methylene blue) release is investigated. Characterization of hydrogels were carried out using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Differential Scanning Calorimetry (DSC). Genipin was used to increase the delivery performance in gastrointestinal tract delivery by decreasing release in simulated stomach conditions and increasing release in simulated intestine conditions. It is shown that the amount of methylene blue released from genipin-cross-linked nanocomposites can be 67.5% higher in intestine medium and 56% lower in the stomach compared to κ-carrageenan hydrogel. It was found that by changing the nanoparticle loading and genipin concentration in the composite, the amount of drug released can be monitored. Therefore, applying nanoparticles appears to be a potential strategy to develop controlled drug delivery especially in gastrointestinal tract studies.
    Matched MeSH terms: Magnesium Oxide/chemistry
  12. Sagadevan S, Marlinda AR, Johan MR, Umar A, Fouad H, Alothman OY, et al.
    J Colloid Interface Sci, 2020 Jan 15;558:68-77.
    PMID: 31585223 DOI: 10.1016/j.jcis.2019.09.081
    We demonstrate the preparation of nanostructures cobalt oxide/reduced graphene oxide (Co3O4/rGO) nanocomposites by a simple one-step cost-effective hydrothermal technique for possible electrode materials in supercapacitor application. The X-ray diffraction patterns were employed to confirm the nanocomposite crystal system of Co3O4/rGO by demonstrating the existence of normal cubic spinel structure of Co3O4 in the matrix of Co3O4/rGO nanocomposite. FTIR and FT-Raman studies manifested the structural behaviour and quality of prepared Co3O4/rGO nanocomposite. The optical properties of the nanocomposite Co3O4/rGO have been investigated by UV absorption spectra. The SEM/TEM images showed that the Co3O4 nanoparticles in the Co3O4/rGO nanocomposites were covered over the surface of the rGO sheets. The electrical properties were analyzed in terms of real and imaginary permittivity, dielectric loss and AC conductivity. The electrocatalytic activities of synthesized Co3O4/rGO nanocomposites were determined by cyclic voltammetry and charge-discharge cycle to evaluate the supercapacitive performance. The specific capacitance of 754 Fg-1 was recorded for Co3O4/rGO nanocomposite based electrode in three electrode cell system. The electrode material exhibited an acceptable capability and excellent long-term cyclic stability by maintaining 96% after 1000 continuous cycles. These results showed that the prepared sample could be an ideal candidate for high-energy application as electrode materials. The synthesized Co3O4/rGO nanocomposite is a versatile material and can be used in various application such as fuel cells, electrochemical sensors, gas sensors, solar cells, and photocatalysis.
    Matched MeSH terms: Magnesium Oxide
  13. Birgani PM, Ranjbar N, Abdullah RC, Wong KT, Lee G, Ibrahim S, et al.
    J Environ Manage, 2016 Dec 15;184(Pt 2):229-239.
    PMID: 27717677 DOI: 10.1016/j.jenvman.2016.09.066
    Considering the chemical properties of batik effluents, an efficient and economical treatment process was established to treat batik wastewater containing not only high levels of Si and chemical oxygen demand (COD), but also toxic heavy metals. After mixing the effluents obtained from the boiling and soaking steps in the batik process, acidification using concentrated hydrochloric acid (conc. HCl) was conducted to polymerize the silicate under acidic conditions. Consequently, sludge was produced and floated. XRD and FT-IR analyses showed that wax molecules were coordinated by hydrogen bonding with silica (SiO2). The acidification process removed ∼78-95% of COD and ∼45-50% of Si, depending on the pH. In the next stage, magnesium oxide (MgO) was applied to remove heavy metals completely and almost 90% of the Si in the liquid phase. During this step, about 70% of COD was removed in the hydrogel that arose as a consequence of the crosslinking characteristics of the formed nano-composite, such as magnesium silicate or montmorillonite. The hydrogel was composed mainly of waxes with polymeric properties. Then, the remaining Si (∼300 mg/L) in the wastewater combined with the effluents from the rinsing steps was further treated using 50 mg/L MgO. As a final step, palm-shell activated carbon (PSAC) was used to remove the remaining COD to 
    Matched MeSH terms: Magnesium Oxide/chemistry
  14. Hezaveh H, Muhamad II
    J Mater Sci Mater Med, 2013 Jun;24(6):1443-53.
    PMID: 23515904 DOI: 10.1007/s10856-013-4914-5
    In this study, MgO nanoparticles are applied to control the initial burst release by modification of matrix structure, thereby affecting the release mechanism. The effects of MgO nanofiller loading on the in vitro release of a model drug are investigated. Surface topography and release kinetics of hydrogel nanocomposites are also studied in order to have better insight into the release mechanism. It was found that the incorporation of MgO nanofillers can significantly decrease the initial burst release. The effect of genipin (GN) on burst release was also compared with MgO nanoparticles, and it was found that the impact of MgO on burst release reduction is more obvious than GN; however, GN cross-linking caused greater final release compared to blanks and nanocomposites. To confirm the capability of nanocomposite hydrogels to reduce burst release, the release of β-carotene in Simulated Gastric Fluid and Simulated Intestinal Fluid was also carried out. Thus, the application of MgO nanoparticles seems to be a promising strategy to control burst release.
    Matched MeSH terms: Magnesium Oxide/chemistry*
  15. Sagadevan S, Venilla S, Marlinda AR, Johan MR, Wahab YA, Zakaria R, et al.
    J Nanosci Nanotechnol, 2020 Apr 01;20(4):2488-2494.
    PMID: 31492266 DOI: 10.1166/jnn.2020.17185
    Herein, we report the effect of synthesis temperature on the morphologies, optical and electronic properties of magnesium oxide (MgO) nanostructures. The MgO nanostructures were synthesized at different temperatures, i.e., 100 °C, 300 °C, and 600 °C by simple chemical reaction process and their morphology, particle size, optical, and electrical properties were examined by different techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV-Vis. spectroscopy. The morphological investigations revealed that various morphologies of MgO nanostructures, i.e., nanoparticles, nanosheet networks, and nanoneedles were synthesized at 100 °C, 300 °C, and 600 °C. The XRD results confirmed that with increasing the synthesis temperature, the crystallinity of the synthesized nanostructures increases. Further, the dielectric properties and AC conductivity at various frequencies for MgO nanostructures were studied which revealed that the dielectric losses decrease with increase in frequency and temperature. In addition, the observed band gap decreases from 4.89 eV to 4.438 eV (100 °C to 600 °C) representing its increase in the conductivity.
    Matched MeSH terms: Magnesium Oxide
  16. Bhavani P, Manikandan A, Jaganathan SK, Shankar S, Antony SA
    J Nanosci Nanotechnol, 2018 Feb 01;18(2):1388-1395.
    PMID: 29448597 DOI: 10.1166/jnn.2018.14112
    Undoped and Mn2+ doped CoAl2O4 (MnxCo1-xAl2O4; x = 0.0 to 1.0) spinel nanoparticles were successfully synthesized by a microwave heating method using glycine as the fuel. X-ray powder diffraction (XRD) was confirmed the cubic spinel structure. The average crystallite size of the samples was found to be in the range of 16.46 nm to 20.25 nm calculated by Scherrer's formula. The nano-sized particle-like morphology of the samples was confirmed by high resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (HR-TEM) analysis. Energy dispersive X-ray (EDX) results showed the pure form of spinel aluminate structure. The band gap energy (Eg) of pure CoAl2O4 was estimated to be 3.68 eV from UV-Visible diffuse reflectance spectroscopy (DRS), and the Eg values increased with increase of Mn2+ ions, due to the smaller grain size. The magnetic hysteresis (M-H) loop showed the superparamagnetic nature, and the magnetization and coercivity values increased with increasing Mn2+ ions, which was confirmed by vibrating sample magnetometer (VSM). All compositions of the nano-catalysts were tested as catalyst successfully for the conversion of benzyl alcohol into benzaldehyde and observed good catalytic activity.
    Matched MeSH terms: Magnesium Oxide
  17. Dabagh S, Chaudhary K, Haider Z, Ali J
    J Nanosci Nanotechnol, 2019 Jul 01;19(7):4142-4146.
    PMID: 30764983 DOI: 10.1166/jnn.2019.16331
    Aluminium substituted cobalt-copper Co1-xCuxFe2-xAlxO₄, (x ═ 0.8) nanoparticles are grown and sintered at different temperature in the range 600 to 900 °C. XRD analysis on nanoparticles prepared at sintered temperatures of 700 °C and 800 °C confirms the spinel structure and presence of hematite phase (alpha ferrite) in them. The dielectric behaviour of the prepared nano-particles is investigated. Although crystallinity improved with increase in sintering temperature and there was a dielectric loss at higher probe analyser frequency. The synthesized nanoparticles an average particle size of 20-24 nm while the FTIR absorption in regions of 586-595 cm-1 and 450-460 cm-1 indicated the presence of intrinsic vibrations of the tetrahedral and octahedral complexes respectively. Electrical resistivity as a function of temperature confirms the semiconducting nature of the Cu-Al substituted cobalt ferrite, and is attributed to the hopping mechanism between Fe2+ Fe3+ ions and Co2+ Cu2+, Co2+ Al3+. The lower values of dielectric constants and dielectric losses make Al-Cu doped cobalt ferrite, a potential material for microwave and radio wave absorber applications.
    Matched MeSH terms: Magnesium Oxide
  18. Suguna S, Shankar S, Jaganathan SK, Manikandan A
    J Nanosci Nanotechnol, 2018 Feb 01;18(2):1019-1026.
    PMID: 29448527 DOI: 10.1166/jnn.2018.13960
    Ni-doped cobalt aluminate NixCo1-xAl2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) spinel nanoparticles were successfully synthesized by a simple microwave combustion method using urea as the fuel and as well as reducing agent. X-ray powder diffraction (XRD) was confirmed the formation of single phase, cubic spinel cobalt-nickel aluminate structure without any other impurities. Average crystallite sizes of the samples were found to be in the range of 18.93 nm to 21.47 nm by Scherrer's formula. Fourier transform infrared (FT-IR) spectral analysis was confirmed the corresponding functional groups of the M-O, Al-O and M-Al-O (M = Co and Ni) bonds of spinel NixCo1-xAl2O4 structure. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images was confirmed the particle like nanostructured morphology. Energy band gap (Eg) value was calculated using UV-Visible diffuse reflectance spectra (DRS) and the Eg values increased with increasing Ni2+ dopant from x = 0.2 (3.58 eV) to x = 1.0 (4.15 eV). Vibrating sample magnetometer (VSM) measurements exposed that undoped and Ni-doped CoAl2O4 samples have superparamagnetic behavior and the magnetization (Ms) values were increased with increasing Ni2+ ions. Spinel NixCo1-xAl2O4 samples has been used for the catalytic oxidation of benzyl alcohol into benzaldehyde and was found that the sample Ni0.6Co0.4Al2O4 showed higher conversion 94.37% with 100% selectivity than other samples, which may be due to the smaller particle size and higher surface area.
    Matched MeSH terms: Magnesium Oxide
  19. Khalajabadi SZ, Abu ABH, Ahmad N, Yajid MAM, Hj Redzuan NB, Nasiri R, et al.
    J Mech Behav Biomed Mater, 2018 Jan;77:360-374.
    PMID: 28985616 DOI: 10.1016/j.jmbbm.2017.09.032
    This study was aimed to improve of the corrosion resistance and mechanical properties of Mg/15TiO2/5HA nanocomposite by silicon and magnesium oxide coatings prepared using a powder metallurgy method. The phase evolution, chemical composition, microstructure and mechanical properties of uncoated and coated samples were characterized. Electrochemical and immersion tests used to investigate the in vitro corrosion behavior of the fabricated samples. The adhesion strength of ~36MPa for MgO and ~32MPa for Si/MgO coatings to substrate was measured by adhesion test. Fabrication a homogenous double layer coating with uniform thicknesses consisting micro-sized particles of Si as outer layer and flake-like particles of MgO as the inner layer on the surface of Mg/15TiO2/5HA nanocomposite caused the corrosion resistance and ductility increased whereas the ultimate compressive stress decreased. However, after immersion in SBF solution, Si/MgO-coated sample indicates the best mechanical properties compared to those of the uncoated and MgO-coated samples. The increase of cell viability percentage of the normal human osteoblast (NHOst) cells indicates the improvement in biocompatibility of Mg/15TiO2/5HA nanocomposite by Si/MgO coating.
    Matched MeSH terms: Magnesium Oxide/chemistry*
  20. Pan GT, Chong S, Yang TC, Huang CM
    Materials (Basel), 2017 Mar 31;10(4).
    PMID: 28772727 DOI: 10.3390/ma10040370
    Mesoporous Mn1.5Co1.5O₄ (MCO) spinel films were prepared directly on a conductive nickel (Ni) foam substrate via electrodeposition and an annealing treatment as supercapacitor electrodes. The electrodeposition time markedly influenced the surface morphological, textural, and supercapacitive properties of MCO/Ni electrodes. The (MCO/Ni)-15 min electrode (electrodeposition time: 15 min) exhibited the highest capacitance among three electrodes (electrodeposition times of 7.5, 15, and 30 min, respectively). Further, an asymmetric supercapacitor that utilizes (MCO/Ni)-15 min as a positive electrode, a plasma-treated activated carbon (PAC)/Ni electrode as a negative electrode, and carboxymethyl cellulose-lithium nitrate (LiNO₃) gel electrolyte (denoted as (PAC/Ni)//(MCO/Ni)-15 min) was fabricated. In a stable operation window of 2.0 V, the device exhibited an energy density of 27.6 Wh·kg-1 and a power density of 1.01 kW·kg-1 at 1 A·g-1. After 5000 cycles, the specific energy density retention and power density retention were 96% and 92%, respectively, demonstrating exceptional cycling stability. The good supercapacitive performance and excellent stability of the (PAC/Ni)//(MCO/Ni)-15 min device can be ascribed to the hierarchical structure and high surface area of the (MCO/Ni)-15 min electrode, which facilitate lithium ion intercalation and deintercalation at the electrode/electrolyte interface and mitigate volume change during long-term charge/discharge cycling.
    Matched MeSH terms: Magnesium Oxide
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