Displaying publications 81 - 100 of 217 in total

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  1. Fulltext Highly Sensitive Magnesium-Doped ZnO Nanorod pH Sensors Based on Electrolyte-Insulator-Semiconductor (EIS) Sensors
    Al-Khalqi EM, Abdul Hamid MA, Al-Hardan NH, Keng LK
    Sensors (Basel), 2021 Mar 17;21(6).
    PMID: 33802968 DOI: 10.3390/s21062110
    For highly sensitive pH sensing, an electrolyte insulator semiconductor (EIS) device, based on ZnO nanorod-sensing membrane layers doped with magnesium, was proposed. ZnO nanorod samples prepared via a hydrothermal process with different Mg molar ratios (0-5%) were characterized to explore the impact of magnesium content on the structural and optical characteristics and sensing performance by X-ray diffraction analysis (XRD), atomic force microscopy (AFM), and photoluminescence (PL). The results indicated that the ZnO nanorods doped with 3% Mg had a high hydrogen ion sensitivity (83.77 mV/pH), linearity (96.06%), hysteresis (3 mV), and drift (0.218 mV/h) due to the improved crystalline quality and the surface hydroxyl group role of ZnO. In addition, the detection characteristics varied with the doping concentration and were suitable for developing biomedical detection applications with different detection elements.
    Matched MeSH terms: Zinc Oxide
  2. Fulltext Synthesis and Characterization of ZnO-SiO2 Composite Using Oil Palm Empty Fruit Bunch as a Potential Silica Source
    Rahmat F, Fen YW, Anuar MF, Omar NAS, Zaid MHM, Matori KA, et al.
    Molecules, 2021 Feb 18;26(4).
    PMID: 33670482 DOI: 10.3390/molecules26041061
    In this paper, the structural and optical properties of ZnO-SiO2-based ceramics fabricated from oil palm empty fruit bunch (OPEFB) were investigated. The OPEFB waste was burned at 600, 700 and 800 °C to form palm ash and was then treated with sulfuric acid to extract silica from the ash. X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses confirmed the existence of SiO2 in the sample. Field emission scanning electron microscopy (FESEM) showed that the particles displayed an irregular shape and became finer after leaching. Then, the solid-state method was used to produce the ZnO-SiO2 composite and the samples were sintered at 600, 800, 1000, 1200 and 1400 °C. The XRD peaks of the Zn2SiO4 showed high intensity, which indicated high crystallinity of the composite. FESEM images proved that the grain boundaries were larger as the temperature increased. Upon obtaining the absorbance spectrum from ultraviolet-visible (UV-Vis) spectroscopy, the energy band gaps obtained were 3.192, 3.202 and 3.214 eV at room temperature, 600 and 800 °C, respectively, and decreased to 3.127, 2.854 and 2.609 eV at 1000, 1200 and 1400 °C, respectively. OPEFB shows high potential as a silica source in producing promising optical materials.
    Matched MeSH terms: Zinc Oxide/chemical synthesis*; Zinc Oxide/chemistry
  3. Emotional maturity of medical students impacting their adult learning skills in a newly established public medical school at the east coast of Malaysian Peninsula
    Bhagat V, Haque M, Bin Abu Bakar YI, Husain R, Khairi CM
    Adv Med Educ Pract, 2016;7:575-584.
    PMID: 27790052
    Emotional maturity (EM) is defined as the ability of an individual to respond to situations, control emotions, and behave in an adult manner when dealing with others. EM is associated with adult learning skill, which is an important aspect of professional development as stated in the principles of andragogy. These principles are basically a characteristic feature of adult learning, which is defined as "the entire range of formal, non-formal, and informal learning activities that are undertaken by adults after an initial education and training, which result in the acquisition of new knowledge and skills". The purpose of this study is to find out the influence of EM on adult learning among Years I and II medical students of Universiti Sultan Zainal Abidin (UniSZA). The study population included preclinical medical students of UniSZA from Years I and II of the academic session 2015/2016. The convenient sampling technique was used to select the sample. Data were collected using "EM scale" to evaluate emotional level and adult learning scale to assess the adult learning scores. Out of 120 questionnaires, only six response sheets were not complete and the remaining 114 (95%) were complete. Among the study participants, 23.7% (27) and 76.3% (87) were males and females, respectively. The data were then compiled and analyzed using SPSS Version 22. The Pearson's correlation method was used to find the significance of their association. The results revealed a significant correlation between EM and adult learning scores (r=0.40, p<0.001). Thus, the study result supports the prediction, and based on the current findings, it can be concluded that there is a significant correlation between EM and adult learning and it has an effect on the students. Medical faculty members should give more emphasis on these aspects to produce health professionals. Henceforward, researchers can expect with optimism that the country will create more rational medical doctors.
    Matched MeSH terms: Zinc Oxide
  4. Phytotoxicity assessment of nano-ZnO on groundnut (arachis hypogaea) seed germination in MS medium
    Ehsan Borzouyan Dastjerdi, Ismail Sahid, Khairiah Jusoh
    Sains Malaysiana, 2016;45:1183-1190.
    Due to the increasing production and use of nanoparticles in various sectors such as electronic industries and healthcare,
    concerns about the unknown effects caused by the presence of these materials in the natural environment and agricultural
    systems were on the rise. Because of the growing trend of ZnO nanoparticles (nZnO) which is one of the most widely
    used nanoparticles being released into the environment, it has attracted the attention for more studies to be done on
    the effects of this nanoparticle on organisms. This study was carried out to investigate the phytotoxicity effect of nZnO
    on groundnut seedlings in Murashige and Skoog (MS) medium. The experimental treatments of this study include eight
    concentrations of nZnO (10, 30, 50, 100, 200, 400, 1000 & 2000 mg.L-1) added to MS medium and MS medium without
    nanoparticles have been used as control treatment. For the first 6 days after sowing, germination percent and germination
    rate index were calculated by counting the germinated seeds every day. Groundnut seedlings were incubated for 3 weeks
    in optimum condition and after that, seedling characteristics such as length, wet and dry weight of radicle and plumule
    were measured. The water content of radicle and plumule were also calculated. The results of this study showed that
    radicle and plumule length of groundnut seedlings were affected by nZnO exposure, in a way that length of radicles in 50
    mg.L-1 nZnO and higher concentrations was significantly lower than that of control treatment and the shortest plumule
    length was observed in 2000 mg.L-1 nZnO concentration treatment. Both the radicle and plumule wet weight were also
    decreased as the nanoparticle concentration was increased. However, despite the decreasing in radicle and plumule dry
    weight with increasing in nZnO concentration, this increase was not significant. However radicle dry weight in 10 mg.L-1
    nZnO was significantly higher than nZnOtreatments with 200 mg.L-1 concentration and higher concentrations. Moreover,
    observations of this study did not show any significant difference between the water content of nZnO concentration
    treatments and control treatment.
    Matched MeSH terms: Zinc Oxide
  5. Optimization of fluoride removal by Al doped ZnO nanoparticles using response surface methodology from groundwater
    Pillai P, Dharaskar S, Khalid M
    Chemosphere, 2021 Dec;284:131317.
    PMID: 34216929 DOI: 10.1016/j.chemosphere.2021.131317
    The current novel work presents the optimization of factors affecting defluoridation by Al doped ZnO nanoparticles using response surface methodology (RSM). Al doped ZnO nanoparticles were synthesized by the sol-gel method and validated by FTIR, XRD, TEM/EDS, TGA, BET, and particle size analysis. Moreover, a central composite design (CCD) was developed for the experimental study to know the interaction between Al doped ZnO adsorbent dosage, initial concentration of fluoride, and contact time on fluoride removal efficiency (response) and optimization of the process. Analysis of variance (ANOVA) was achieved to discover the importance of the individual and the effect of variables on the response. The model predicted that the response significantly correlated with the experimental response (R2 = 0.97). Among the factors, the effect of adsorbent dose and contact time was considered to have more influence on the response than the concentration. The optimized process parameters by RSM presented the adsorbent dosage: 0.005 g, initial concentration of fluoride: 1.5 g/L, and contact time: 5 min, respectively. Kinetic, isotherm, and thermodynamic studies were also investigated. The co-existing ions were also studied. These results demonstrated that Al doped ZnO could be a promising adsorbent for effective defluoridation for water.
    Matched MeSH terms: Zinc Oxide*
  6. Anticariogenic and Mechanical Characteristics of Resin-Modified Glass Ionomer Cement Containing Lignin-Decorated Zinc Oxide Nanoparticles
    Malik Z, Muhammad N, Kaleem M, Nayyar M, Qazi AS, Butt DQ, et al.
    ACS Appl Bio Mater, 2023 Feb 20;6(2):425-435.
    PMID: 36700919 DOI: 10.1021/acsabm.2c00644
    This study aims to synthesize and characterize lignin-decorated zinc oxide nanoparticles before incorporating them into resin-modified glass ionomer cement (RMGIC) to improve their anticariogenic potential and mechanical properties (shear bond strength and microhardness). Probe sonication was used to synthesize lignin-decorated zinc oxide nanoparticles which were then characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Following characterization, these were incorporated in RMGIC (Gold label, Fuji II LC). Three major groups, experimental group A (EGA), experimental group B (EGB), and control group (CG), were outlined. EGA and EGB were divided into numbered subgroups based on the ascending concentrations of nanoparticles (5, 10, and 15%) of lignin-coated zinc oxide and zinc-oxide, respectively. CG served as a control and comprised cured RMGIC samples without any incorporation. Anticariogenic analysis was conducted on experimental RMGIC samples via disk-diffusion (n = 3) and direct contact test (n = 3) against Streptococcus mutans (ATCC 25175). Optical density values for days 1, 3, and 5 were recorded via a UV-Vis spectrophotometer. A shear bond strength test was performed using 35 premolars. The adhesive remnant index was used to estimate the site of bond failure. For the Vickers microhardness test (n = 3), 100 g of load at 10 s dwell time was set. Atomic absorption spectroscopy was performed over 28 days to determine the release of zinc from the samples. All tests were analyzed statistically. The anticariogenic potential of EGA and EGB was significantly greater (p ≤ 0.05) than that of the control. The shear bond strength test reported the highest value for EGA15 with all groups exhibiting failure at the bracket/RMGIC interface. The microhardness of EGA15 yielded the highest value (p ≤ 0.05). Release kinetics displayed a steady release with EGB15 exhibiting the highest value. The EGA and EGB samples displayed good anticariogenic potential, which was sustained for 28 days without any deleterious effect on the shear bond strength and microhardness.
    Matched MeSH terms: Zinc Oxide*
  7. Fulltext Morphology tuning of ZnO nanostructures grown on zinc foil using facile and low temperature hydrothermal method
    Daud, S.N.H., Chiu, W.S., Aspanut, Z., Khiew, P.S.
    Malaysian Journal of Microscopy, 2015;11(1):50-55.
    MyJurnal
    Current study report the growth of Zinc Oxide (ZnO) nanorods (NRs) by a facile and low temperature method on Zinc (Zn) foil in deionized (DI) water. These ZnO NRs have a typical length of 500-700 nm and average diameter of 50-70 nm. By using different volume of DI water, the morphology of ZnO nanostructures are tunable from rod-like to flower-like structures. Under the presence of Zn nitrate precursor, mixture of rod/wall-like structures are formed. Both of ZnO NRs and combined nanorods/nanowalls render higher diffraction for the (002) peak reveals, which implies preferred orientation growth along c-axis take place. However, photoluminescence (PL) study indicates that ZnO NRs have strong emission located at ~380 nm if compared to that of combined ZnO nanorods/nanowalls. This shows that ZnO NRs have higher-densities of defects.
    Matched MeSH terms: Zinc Oxide
  8. Fulltext Light-Addressable Potentiometric Sensors Using ZnO Nanorods as the Sensor Substrate for Bioanalytical Applications
    Tu Y, Ahmad N, Briscoe J, Zhang DW, Krause S
    Anal Chem, 2018 07 17;90(14):8708-8715.
    PMID: 29932632 DOI: 10.1021/acs.analchem.8b02244
    Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images. Herein, for the first time, the use of 1D semiconducting oxides in the form of ZnO nanorods for LAPS imaging is explored to solve this issue. A significantly increased AC photocurrent with enhanced image resolution has been achieved based on ZnO nanorods, with a photocurrent of 45.7 ± 0.1 nA at a light intensity of 0.05 mW, a lateral resolution as low as 3.0 μm as demonstrated by images of a PMMA dot on ZnO nanorods and a pH sensitivity of 53 mV/pH. The suitability of the device for bioanalysis and bioimaging was demonstrated by monitoring the degradation of a thin poly(ester amide) film with the enzyme α-chymotrypsin using LAPS. This simple and robust route to fabricate LAPS substrates with excellent performance would provide tremendous opportunities for bioimaging.
    Matched MeSH terms: Zinc Oxide/chemistry*
  9. Fulltext Cellular accumulation and cytotoxic effects of zinc oxide nanoparticles in microalga Haematococcus pluvialis
    Djearamane S, Lim YM, Wong LS, Lee PF
    PeerJ, 2019;7:e7582.
    PMID: 31579572 DOI: 10.7717/peerj.7582
    Background: Zinc oxide nanoparticles (ZnO NPs) are widely used in household and cosmetic products which imply an increased releasing of these particles into the environment, especially aquatic ecosystems, resulting in the need of assessing the potential toxic effects of ZnO NPS on the aquatic organisms, particularly on microalgae which form the base for food chain of aquatic biota. The present study has investigated the dose- and time-dependent cellular accumulation and the corresponding cytotoxic effects of increasing concentrations of ZnO NPs from 10-200 μg/mL on microalga Haematococcus pluvialis at an interval of 24 h for 96 h.

    Methods: The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) was used to qualitatively detect the cellular accumulation of ZnO NPs in algal cells, while inductively coupled plasma optical emission spectrometry (ICP OES) was performed to quantify the cell associated-zinc in algal cells. The percentage of cell death, reduction in algal biomass, and loss in photosynthetic pigments were measured to investigate the cytotoxic effects of ZnO NPs on H. pluvialis. Extracellular and intracellular changes in algal cells resulted from the treatment of ZnO NPs were demonstrated through optical, scanning, and transmission electron microscopic studies.

    Results: SEM-EDX spectrum evidenced the accumulation of ZnO NPs in algal biomass and ICP OES results reported a significant (p < 0.05) dose- and time-dependent accumulation of zinc in algal cells from 24 h for all the tested concentrations of ZnO NPs (10-200 μg/mL). Further, the study showed a significant (p < 0.05) dose- and time-dependent growth inhibition of H. pluvialis from 72 h at 10-200 μg/mL of ZnO NPs. The morphological examinations revealed substantial surface and intracellular damages in algal cells due to the treatment of ZnO NPs.

    Discussion: The present study reported the significant cellular accumulation of ZnO NPs in algal cells and the corresponding cytotoxic effects of ZnO NPs on H. pluvialis through the considerable reduction in algal cell viability, biomass, and photosynthetic pigments together with surface and intracellular damages.

    Matched MeSH terms: Zinc Oxide
  10. Ameliorating Cu2+ reduction in microbial fuel cell with Z-scheme BiFeO3 decorated on flower-like ZnO composite photocathode
    Lam SM, Sin JC, Zeng H, Lin H, Li H, Mohamed AR, et al.
    Chemosphere, 2022 Jan;287(Pt 4):132384.
    PMID: 34597645 DOI: 10.1016/j.chemosphere.2021.132384
    BiFeO3 nanoparticle decorated on flower-like ZnO (BiFeO3/ZnO) was fabricated through a facile hydrothermal-reflux combined method. This material was utilized as a composite photocathode for the first time in microbial fuel cell (MFC) to reduce the copper ion (Cu2+) and power generation concomitantly. The resultant BiFeO3/ZnO-based MFC displayed distinct photoelectrocatalytic activities when different weight percentages (wt%) BiFeO3 were used. The 3 wt% BiFeO3/ZnO MFC achieved the maximum power density of 1.301 W m-2 in the catholyte contained 200 mg L-1 of Cu2+ and the power density was greatly higher than those pure ZnO and pure BiFeO3 photocathodes. Meanwhile, the MFC exhibited 90.7% removal of Cu2+ within 6 h under sunlight exposure at catholyte pH 4. The addition of BiFeO3 nanoparticles not only manifested outstanding capability in harvesting visible light, but also facilitated the formation of Z-scheme BiFeO3/ZnO heterojunction structure to induce the charge carrier transfer along with enhanced redox abilities for the cathodic reduction. The pronounced electrical output and Cu2+ reduction efficiencies can be realized through the synergistic cooperation between the bioanode and BiFeO3/ZnO photocathode in the MFC. Furthermore, the developed BiFeO3/ZnO composite presented a good stability and reusability of photoelectrocatalytic activity up to five cyclic runs.
    Matched MeSH terms: Zinc Oxide*
  11. Fulltext Growth of ZnO nanorods on stainless steel wire using chemical vapour deposition and their photocatalytic activity
    Abd Aziz SN, Pung SY, Ramli NN, Lockman Z
    ScientificWorldJournal, 2014;2014:252851.
    PMID: 24587716 DOI: 10.1155/2014/252851
    The photodegradation efficiency of ZnO nanoparticles in removal of organic pollutants deteriorates over time as a high percentage of the nanoparticles can be drained away by water during the wastewater treatment. This problem can be solved by growing the ZnO nanorods on stainless steel wire. In this work, ZnO nanorods were successfully grown on stainless steel wire by chemical vapour deposition. The SAED analysis indicates that ZnO nanorod is a single crystal and is preferentially grown in [0001] direction. The deconvoluted O 1s peak at 531.5 eV in XPS analysis is associated with oxygen deficient, revealing that the ZnO nanorods contain many oxygen vacancies. This observation is further supported by the finding of the small I(uv)/I(vis) ratio, that is, ~1 in the photoluminescence analysis. The growth of ZnO nanorods on stainless steel wire was governed by vapour-solid mechanism as there were no Fe particles observed at the tips of the nanorods. The photodegradation of Rhodamine B solution by ZnO nanorods followed the first-order kinetics.
    Matched MeSH terms: Zinc Oxide/chemistry*
  12. Fulltext Fabrication and Characterization of Glucose Biosensors by Using Hydrothermally Grown ZnO Nanorods
    Ridhuan NS, Abdul Razak K, Lockman Z
    Sci Rep, 2018 09 13;8(1):13722.
    PMID: 30213995 DOI: 10.1038/s41598-018-32127-5
    Highly oriented ZnO nanorod (NR) arrays were fabricated on a seeded substrate through a hydrothermal route. The prepared ZnO nanorods were used as an amperometric enzyme electrode, in which glucose oxidase (GOx) was immobilised through physical adsorption. The modified electrode was designated as Nafion/GOx/ZnO NRs/ITO. The morphology and structural properties of the fabricated ZnO nanorods were analysed using field-emission scanning electron microscope and X-ray diffractometer. The electrochemical properties of the fabricated biosensor were studied by cyclic voltammetry and amperometry. Electrolyte pH, electrolyte temperature and enzyme concentration used for immobilisation were the examined parameters influencing enzyme activity and biosensor performance. The immobilised enzyme electrode showed good GOx retention activity. The amount of electroactive GOx was 7.82 × 10-8 mol/cm2, which was relatively higher than previously reported values. The Nafion/GOx/ZnO NRs/ITO electrode also displayed a linear response to glucose ranging from 0.05 mM to 1 mM, with a sensitivity of 48.75 µA/mM and a low Michaelis-Menten constant of 0.34 mM. Thus, the modified electrode can be used as a highly sensitive third-generation glucose biosensor with high resistance against interfering species, such as ascorbic acid, uric acid and L-cysteine. The applicability of the modified electrode was tested using human blood samples. Results were comparable with those obtained using a standard glucometer, indicating the excellent performance of the modified electrode.
    Matched MeSH terms: Zinc Oxide/chemistry*
  13. Fulltext SYNTHESIS AND CHARACTERIZATION OF TiO2/ZnO-EPOXY BEADS AND THEIR PERFORMANCE FOR THE DEGRADATION OF DYE
    MOHAMAD HANIF AKMAL HUSSIN, WAN RAFIZAH WAN ABDULLAH, MOHAMAD AWANG
    UMT Journal of Undergraduate Research, 2020;2(2):9-14.
    MyJurnal
    Semiconductor oxides such as titanium dioxide (TiO2) and zinc oxide (ZnO) are used as the photocatalyst for removing contaminants. In addition, TiO2 and ZnO nanoparticles in the suspension form makes it difficult to be recovered and recycled. This study was conducted to investigate the efficiency of immobilizing TiO2 and ZnO nanoparticles in epoxy beads. The immobilization process using different ratios of photocatalysts TiO2/ZnO (1:0, 3:1, 1:1, 1:3 and 0:1) fixed on epoxy material. These epoxy beads were used for dye removal in photocatalysis using methylene blue (MB) solution at a concentration of 10mg/L. Besides, epoxy beads also characterized using scanning electron microscope (SEM), attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the highly recommended epoxy bead is 3:1 ratio of TiO2/ZnO because it has good performance in dye degradation that proved from reducing concentration of MB to 2.4mg/L (76%). However, TiO2/ZnO characterization of 3:1 by SEM show on the surface the particle are found to be spherical in shape which is relatively high efficiency for the degradation, ATR-FTIR pattern in broad band 4000 cm-1 - 400cm-1 which correspond to hydroxyl stretching to be adsorbed at peak (474.49 cm-1 - 3722.61cm-1) respectively to the optimum for the degradation and TGA rate of change are 5mg to 2.5mg that residue (49.78%) due to decomposition or oxidation from mass loss. These findings are very effective and economical technique to be cost saving and highly efficient photocatalyst.
    Matched MeSH terms: Zinc Oxide
  14. Fulltext Green Microwave-Assisted Combustion Synthesis of Zinc Oxide Nanoparticles with Citrullus colocynthis (L.) Schrad: Characterization and Biomedical Applications
    Azizi S, Mohamad R, Mahdavi Shahri M
    Molecules, 2017 Feb 16;22(2).
    PMID: 28212344 DOI: 10.3390/molecules22020301
    In this paper, a green microwave-assisted combustion approach to synthesize ZnO-NPs using zinc nitrate and Citrullus colocynthis (L.) Schrad (fruit, seed and pulp) extracts as bio-fuels is reported. The structure, optical, and colloidal properties of the synthesized ZnO-NP samples were studied. Results illustrate that the morphology and particle size of the ZnO samples are different and depend on the bio-fuel. The XRD results revealed that hexagonal wurtzite ZnO-NPs with mean particle size of 27-85 nm were produced by different bio-fuels. The optical band gap was increased from 3.25 to 3.40 eV with the decreasing of particle size. FTIR results showed some differences in the surface structures of the as-synthesized ZnO-NP samples. This led to differences in the zeta potential, hydrodynamic size, and more significantly, antioxidant activity through scavenging of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals. In in vitro cytotoxicity studies on 3T3 cells, a dose dependent toxicity with non-toxic effect of concentration below 0.26 mg/mL was shown for ZnO-NP samples. Furthermore, the as-synthesized ZnO-NPs inhibited the growth of medically significant pathogenic gram-positive (Bacillus subtilis and Methicillin-resistant Staphylococcus aurous) and gram-negative (Peseudomonas aeruginosa and Escherichia coli) bacteria. This study provides a simple, green and efficient approach to produce ZnO nanoparticles for various applications.
    Matched MeSH terms: Zinc Oxide/chemistry*
  15. Fulltext High-performance dye-sensitized solar cells based on morphology-controllable synthesis of ZnO-ZnS heterostructure nanocone photoanodes
    Rouhi J, Mamat MH, Ooi CH, Mahmud S, Mahmood MR
    PLoS One, 2015;10(4):e0123433.
    PMID: 25875377 DOI: 10.1371/journal.pone.0123433
    High-density and well-aligned ZnO-ZnS core-shell nanocone arrays were synthesized on fluorine-doped tin oxide glass substrate using a facile and cost-effective two-step approach. In this synthetic process, the ZnO nanocones act as the template and provide Zn2+ ions for the ZnS shell formation. The photoluminescence spectrum indicates remarkably enhanced luminescence intensity and a small redshift in the UV region, which can be associated with the strain caused by the lattice mismatch between ZnO and ZnS. The obtained diffuse reflectance spectra show that the nanocone-based heterostructure reduces the light reflection in a broad spectral range and is much more effective than the bare ZnO nanocone and nanorod structures. Dye-sensitized solar cells based on the heterostructure ZnO-ZnS nanocones are assembled, and high conversion efficiency (η) of approximately 4.07% is obtained. The η improvement can be attributed primarily to the morphology effect of ZnO nanocones on light-trapping and effectively passivating the interface surface recombination sites of ZnO nanocones by coating with a ZnS shell layer.
    Matched MeSH terms: Zinc Oxide/chemistry*
  16. Application of antimicrobial active packaging film made of semolina flour, nano zinc oxide and nano-kaolin to maintain the quality of low-moisture mozzarella cheese during low-temperature storage
    Jafarzadeh S, Rhim JW, Alias AK, Ariffin F, Mahmud S
    J Sci Food Agric, 2019 Apr;99(6):2716-2725.
    PMID: 30350410 DOI: 10.1002/jsfa.9439
    BACKGROUND: Active food packaging films with improved properties and strong antimicrobial activity were prepared by blending mixed nanomaterials with different ratio [1:4 (40 mg:160 mg), 3:2 (120 mg: 80 mg), 0:5 (0 mg: 200 mg) and 5:0 (200 mg:0 mg)] of ZnO and kaolin with semolina using a solvent casting method and used for the packaging of low moisture mozzarella cheese to test the effect of packaging on the quality change of the cheese for long-term (up to 72 days) refrigerated storage.

    RESULTS: Compared with the neat semolina film, mechanical strength (TS) of the nanocomposite films increased significantly (increase in 21-65%) and water vapor barrier (WVP) and O2 gas barrier (OP) properties decreased significantly (decrease in 43-50% and 60-65%, respectively) depending on the blending ratio of ZnO and kaolin nanoclay. The nanocomposite films also exhibited strong antimicrobial activity against bacteria (E. coli and S. aureus), yeast (C. albicans), and mold (A. niger). The nanocomposite packaging films were effectively prevented the growth of microorganisms (coliforms, total microbial, and fungi) of the cheese during storage at low-temperature and showed microbial growth of less than 2.5 log CFU/g after 72 days of storage compared to the control group, and the quality of the packaged cheese was still acceptable.

    CONCLUSION: The semolina-based nanocomposite films, especially Sem/Z3 K2 film, were effective for packaging of low moisture mozzarella cheese to maintain the physicochemical properties (pH, moisture, and fat content) and quality (color, taste, texture, and overall acceptability) of the cheese as well as preventing microbial growth (coliforms, total microbial, and fungi). © 2018 Society of Chemical Industry.

    Matched MeSH terms: Zinc Oxide/pharmacology*; Zinc Oxide/chemistry
  17. Fulltext Effect of nanoparticles concentration on electromagnetic-assisted oil recovery using ZnO nanofluids
    Adil M, Lee K, Mohd Zaid H, A Shukur MF, Manaka T
    PLoS One, 2020;15(12):e0244738.
    PMID: 33382855 DOI: 10.1371/journal.pone.0244738
    Utilization of metal-oxide nanoparticles (NPs) in enhanced oil recovery (EOR) has generated substantial recent research interest in this area. Among these NPs, zinc oxide nanoparticles (ZnO-NPs) have demonstrated promising results in improving oil recovery due to their prominent thermal properties. These nanoparticles can also be polarized by electromagnetic (EM) field, which offers a unique Nano-EOR approach called EM-assisted Nano-EOR. However, the impact of NPs concentrations on oil recovery mechanism under EM field has not been well established. For this purpose, ZnO nanofluids (ZnO-NFs) of two different particle sizes (55.7 and 117.1 nm) were formed by dispersing NPs between 0.01 wt.% to 0.1 wt.% in a basefluid of sodium dodecylbenzenesulfonate (SDBS) and NaCl to study their effect on oil recovery mechanism under the electromagnetic field. This mechanism involved parameters, including mobility ratio, interfacial tension (IFT) and wettability. The displacement tests were conducted in water-wet sandpacks at 95˚C, by employing crude oil from Tapis. Three tertiary recovery scenarios have been performed, including (i) SDBS surfactant flooding as a reference, (ii) ZnO-NFs flooding, and (iii) EM-assisted ZnO-NFs flooding. Compare with incremental oil recovery from surfactant flooding (2.1% original oil in place/OOIP), nanofluid flooding reaches up to 10.2% of OOIP at optimal 0.1 wt.% ZnO (55.7 nm). Meanwhile, EM-assisted nanofluid flooding at 0.1 wt.% ZnO provides a maximum oil recovery of 10.39% and 13.08% of OOIP under EM frequency of 18.8 and 167 MHz, respectively. By assessing the IFT/contact angle and mobility ratio, the optimal NPs concentration to achieve a favorable ER effect and interfacial disturbance is determined, correlated to smaller hydrodynamic-sized nanoparticles that cause strong electrostatic repulsion between particles.
    Matched MeSH terms: Zinc Oxide*
  18. Spectroscopic studies of Er3+-Yb3+ codoped multicomposition tellurite oxide glass
    Baki S, Tan L, Kan C, Kamari H, Noor A, Mardi M
    Sains Malaysiana, 2014;43:843-850.
    Multicomposition of Er3+ -Y11-3+ codoped tellurite oxide, Te02-ZnO-PbO-Ti02-Na20 glass has been investigated. A detailed spectroscopic study of the Judd-Ofelt analysis has been performed from the measured absorption spectrum in order to obtain the intensity parameters S2, (t=2, 4, 6). The calculated S2, values were then utilized in the determination of transition probabilities, radiative lifetimes and branching ratios of the Er3+ transitions between the J(upper)-J'(lower) manifolds. Both visible upconversion and near-infrared spectra were characterized under the 980 nm laser diode excitation at room temperature.
    Matched MeSH terms: Zinc Oxide
  19. Fulltext Synergistic Effects of Pr6O11 and Co3O4 on Electrical and Microstructure Features of ZnO-BaTiO3 Varistor Ceramics
    Shaifudin MS, Ghazali MSM, Kamaruzzaman WMIWM, Wan Abdullah WR, Kassim S, Ismail NQA, et al.
    Materials (Basel), 2021 Feb 03;14(4).
    PMID: 33546094 DOI: 10.3390/ma14040702
    This paper investigated the effects of Pr6O11 and Co3O4 on the electrical properties of ZnO-BaTiO3 varistor ceramics. The Pr6O11 doping has a notable influence on the characteristics of the nonlinear coefficient, varistor voltage, and leakage current where the values varied from 2.29 to 2.69, 12.36 to 68.36 V/mm and 599.33 to 548.16 µA/cm2, respectively. The nonlinear varistor coefficient of 5.50 to 7.15 and the varistor voltage of 7.38 to 8.10 V/mm was also influenced by the use of Co3O4 as a dopant. When the amount of Co3O4 was above 0.5 wt.%, the leakage current increased from 202.41 to 302.71 μA/cm2. The varistor ceramics with 1.5 wt.% Pr6O11 shows good nonlinear electrical performance at higher breakdown voltage and reduced the leakage current of the ceramic materials. Besides, the varistor sample that was doped with 0.5 wt.% Co3O4 was able to enhance the nonlinear electrical properties at low breakdown voltage with a smaller value of leakage current.
    Matched MeSH terms: Zinc Oxide
  20. Fulltext Down-top nanofabrication of binary (CdO)x (ZnO)1-x nanoparticles and their antibacterial activity
    Al-Hada NM, Mohamed Kamari H, Abdullah CAC, Saion E, Shaari AH, Talib ZA, et al.
    Int J Nanomedicine, 2017;12:8309-8323.
    PMID: 29200844 DOI: 10.2147/IJN.S150405
    In the present study, binary oxide (cadmium oxide [CdO])x (zinc oxide [ZnO])1-x nanoparticles (NPs) at different concentrations of precursor in calcination temperature were prepared using thermal treatment technique. Cadmium and zinc nitrates (source of cadmium and zinc) with polyvinylpyrrolidone (capping agent) have been used to prepare (CdO)x (ZnO)1-x NPs samples. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD patterns analysis revealed that NPs were formed after calcination, which showed a cubic and hexagonal crystalline structure of (CdO)x (ZnO)1-x NPs. The phase analysis using EDX spectroscopy and FTIR spectroscopy confirmed the presence of Cd and Zn as the original compounds of prepared (CdO)x (ZnO)1-x NP samples. The average particle size of the samples increased from 14 to 33 nm as the concentration of precursor increased from x=0.20 to x=0.80, as observed by TEM results. The surface composition and valance state of the prepared product NPs were determined by X-ray photoelectron spectroscopy (XPS) analyses. Diffuse UV-visible reflectance spectra were used to determine the optical band gap through the Kubelka-Munk equation; the energy band gap was found to decrease for CdO from 2.92 to 2.82 eV and for ZnO from 3.22 to 3.11 eV with increasing x value. Additionally, photoluminescence (PL) spectra revealed that the intensity in PL increased with an increase in particle size. In addition, the antibacterial activity of binary oxide NP was carried out in vitro against Escherichia coli ATCC 25922 Gram (-ve), Salmonella choleraesuis ATCC 10708, and Bacillus subtilis UPMC 1175 Gram (+ve). This study indicated that the zone of inhibition of 21 mm has good antibacterial activity toward the Gram-positive B. subtilis UPMC 1175.
    Matched MeSH terms: Zinc Oxide/pharmacology; Zinc Oxide/chemistry*
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