Displaying publications 881 - 900 of 1298 in total

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  1. Molecularly imprinted polymer for the removal of diclofenac from water: Synthesis and characterization
    Samah NA, Sánchez-Martín MJ, Sebastián RM, Valiente M, López-Mesas M
    Sci Total Environ, 2018 Aug 01;631-632:1534-1543.
    PMID: 29727977 DOI: 10.1016/j.scitotenv.2018.03.087
    Contaminants of Emerging Concerns (CECs) have been introduced as one type of recalcitrant pollutant sources in water. In this study, the non-steroidal anti-inflammatory drug diclofenac (DCF) has been removed from water solutions using Molecularly Imprinted Polymer (MIP), synthetized via bulk polymerization with allylthiourea (AT) as the functional monomer and using DCF as template (MIP-DCF). DCF detection has been performed by UV spectrophotometer. From the kinetic study in batch mode, approximately 100% of removal is observed by using 10mg of MIP-DCF, with an initial concentration of 5mg/L of DCF at pH7, within 3min and agitated at 25°C. In continuous flow mode study, using a cartridge pre-packed with 10mg of MIP-DCF, a high adsorption capacity of 160mgDCF/g MIP was obtained. To study the porosity of MIPs, scanning electron microscopy (SEM) has been used. In order to characterize the chemical interaction between monomer and template, the pre-polymerization mixture for MIP and DCF has also been studied by 1H NMR. One of the chemical shift observed has been related to the formation of a complex between amine protons of thiourea group of AT with carboxylic acid on DCF. In conclusion, the developed MIP works as a good adsorbent for DCF removal, and is selective to DCF in the presence of indomethacin and ibuprofen.
    Matched MeSH terms: Microscopy, Electron, Scanning
  2. Fulltext Optimization of Aceclofenac Proniosomes by Using Different Carriers, Part 1: Development and Characterization
    Sammour RMF, Taher M, Chatterjee B, Shahiwala A, Mahmood S
    Pharmaceutics, 2019 Jul 18;11(7).
    PMID: 31323799 DOI: 10.3390/pharmaceutics11070350
    In the contemporary medical model world, the proniosomal system has been serving as a new drug delivery system that is considered to significantly enhance the bioavailability of drugs with low water solubility. The application of this system can improve the bioavailability of aceclofenac that is used for the relief of pain and inflammation in osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis. The present study is intended to develop an optimized proniosomal aceclofenac formula by the use of different carriers. Aceclofenac proniosomes have been prepared by slurry method, and different carriers such as maltodextrin, mannitol, and glucose were tried. Prepared proniosomes characterized by differential scanning calorimetry (DSC) analysis and Fourier transform infrared (FTIR) analysis revealed the compatibility of the drug chosen with the ingredient added, powder X-ray diffractometry (XRD) confirmed the amorphous phase of the prepared proniosomes, and finally, the surfactant layer was observed by scanning electron microscopy (SEM). Aceclofenac physical state transformations were confirmed with all formulas but maltodextrin proniosomes exhibited solubility more than other formulations. HPLC method has been used to analyze the niosomes derived from proniosomes in terms of their entrapment capability and drug content. The obtained results revealed that aceclofenac proniosomes can be successfully prepared by using different carriers.
    Matched MeSH terms: Microscopy, Electron, Scanning
  3. Culture optimization for production and characterization of bioflocculant by Aspergillus flavus grown on chicken viscera hydrolysate
    Mohammed JN, Wan Dagang WRZ
    World J Microbiol Biotechnol, 2019 Jul 22;35(8):121.
    PMID: 31332590 DOI: 10.1007/s11274-019-2696-8
    The economics of bioflocculant production is coupled with the use of a low-cost substrate at appropriate culture conditions. The use of a waste substrate for this purpose offers an additional treatment measure to mitigate environmental pollution. We investigated the growth of Aspergillus flavus and its bioflocculant yield using chicken viscera hydrolysate as the sole media. The effects of culture conditions including time, pH, shaker speed, temperature and inoculum size on bioflocculant production were all investigated and optimised through response surface method based on the central component design (CCD) package of Design Expert. Next, the purified bioflocculant was physically and chemically characterised. Under optimised culture conditions (incubation time 72 h, pH 7, shaker speed 150 rpm, temperature 35 °C and inoculum 4%), 6.75 g/L yield of crude bioflocculant was recorded. The bioflocculant activity was mostly distributed in the cell-free supernatant with optimum efficiency of 91.8% at a dose of 4 mL/100 mL Kaolin suspension. The purified bioflocculant was a glycoprotein consisting of 23.46% protein and 74.5% sugar, including 46% neutral sugar and 2.01% uronic acid. The X-ray photoelectron spectroscopy fundamental analysis of the purified bioflocculant indicated that the mass proportion of C, O and N, were 63.46%, 27.87% and 8.86%, respectively. The bioflocculant is mainly composed of carbonyl, amino, hydroxyl, and amide functional groups. This study for the first time indicates a high potential of bioflocculant yield from chicken viscera at the appropriate culture conditions.
    Matched MeSH terms: Microscopy, Electron, Scanning
  4. Bioinspired 2D carbon sheets decorated with MnFe2O4 nanoparticles for preconcentration of inorganic arsenic, and its determination by ICP-OES
    Ahmad H, Haseen U, Umar K, Ansari MS, Ibrahim MNM
    Mikrochim Acta, 2019 08 27;186(9):649.
    PMID: 31456042 DOI: 10.1007/s00604-019-3753-6
    The authors describe a method for solvent-free mechano-chemical synthesis of a bioinspired sorbent. A 2D ultra-thin carbon sheet similar to graphene oxide was prepared using a natural waste (onion sheet). The formation of 2D carbon sheets was confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy and ATR-IR. The surface morphology was characterized by field emission scanning electron microscopy and high-resolution tunneling electron microscopy. The carbon sheets were decorated with crystalline MnFe2O4 nanoparticles by solid-state reaction at room temperature. The presence of magnetic particles in the final product was confirmed by vibrating sample magnetometry and electron microscopy. The synergistic effect of carbon sheets and MnFe2O4 led to an enhanced sorption of arsenic species compared to bare carbon sheets or to MnFe2O4 nanoparticles. A column was prepared for the simultaneous preconcentration and determination of trace levels of As(III) and As(V) from water samples. The preconcentration factors are between 900 and 833 for As(III) and As(V) species, respectively. The linearity of the calibration plot ranges from 0.4-10 ng mL-1. The detection limits (at 3σ) for both As(III) and As(V) are 30 pg mL-1. The Student's t values for the analysis of spiked samples are lower than the critical Student's t values at a 95% confidence level. The recoveries from spiked water samples range between 99 and 102.8%. Graphical abstract Schematic representation of the preparation of carbon sheets similar to graphene oxide from onion sheaths after pyrolysis at 800 °C. The prepared carbon sheet-MnFe2O4 composite shows excellent arsenic sorption and preconcentration down to the pg mL-1 concentration.
    Matched MeSH terms: Microscopy, Electron, Scanning
  5. Fulltext Adsorption of sulfur dioxide (SO2) gas using treated rice husk ash (RHA) adsorbent
    Nurul Najwa Abd Malek, Rusdin Laiman
    Science Letters, 2018;12(1):63-76.
    MyJurnal
    The aim of this study was to investigate the potential of treated rice husk ash (RHA) as adsorbent to adsorb acidic SO2 gas. The treated RHA was prepared using a water hydration method by mixing the RHA, Calcium oxide (CaO) and Sodium Hydroxide (NaOH). The addition of NaOH is to increase the dissolution of silica from the RHA to form reactive species responsible for higher desulfurization activity. The untreated and treated RHA were subjected to several characterizations and the characteristics of the adsorbents were compared. The functional groups present on the surface of the adsorbent were determined using Fourier Transform Infrared (FTIR). The chemical composition of the untreated and treated RHA was analyzed by using X-ray Fluorescence (XRF). Scanning electron microscope (SEM) analysis showed that the treated RHA has higher porosity compared to untreated RHA. Based on the SO2 adsorption analysis, it was found that the treated RHA has higher adsorption capacity, 62.22 mg/g, compared to untreated RHA, 1.49 mg/g.
    Matched MeSH terms: Microscopy, Electron, Scanning
  6. Label-Free Time-of-Flight Secondary Ion Mass Spectrometry Imaging of Sulfur-Producing Enzymes inside Microglia Cells following Exposure to Silver Nanowires
    Leo BF, Fearn S, Gonzalez-Cater D, Theodorou I, Ruenraroengsak P, Goode AE, et al.
    Anal Chem, 2019 Sep 03;91(17):11098-11107.
    PMID: 31310103 DOI: 10.1021/acs.analchem.9b01704
    There are no methods sensitive enough to detect enzymes within cells, without the use of analyte labeling. Here we show that it is possible to detect protein ion signals of three different H2S-synthesizing enzymes inside microglia after pretreatment with silver nanowires (AgNW) using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Protein fragment ions, including the fragment of amino acid (C4H8N+ = 70 amu), fragments of the sulfur-producing cystathionine-containing enzymes, and the Ag+ ion signal could be detected without the use of any labels; the cells were mapped using the C4H8N+ amino acid fragment. Scanning electron microscopy imaging and energy-dispersive X-ray chemical analysis showed that the AgNWs were inside the same cells imaged by TOF-SIMS and transformed chemically into crystalline Ag2S within cells in which the sulfur-producing proteins were detected. The presence of these sulfur-producing cystathionine-containing enzymes within the cells was confirmed by Western blots and confocal microscopy images of fluorescently labeled antibodies against the sulfur-producing enzymes. Label-free TOF-SIMS is very promising for the label-free identification of H2S-contributing enzymes and their cellular localization in biological systems. The technique could in the future be used to identify which of these enzymes are most contributory.
    Matched MeSH terms: Microscopy, Electron, Scanning
  7. Production of biodiesel from palm fatty acid distillate by microwave-assisted sulfonated glucose acid catalyst
    Nur Nazlina Saimon, Heng Khuan Eu, Anwar Johari, Norzita Ngadi, Mazura Jusoh, Zaki Yamani Zakaria
    Sains Malaysiana, 2018;47:109-115.
    Biodiesel, one of the renewable energy sources has gained attention for decades as the alternative fuel due to its remarkable properties. However, there are several drawbacks from the industrial production of biodiesel such as the spike in the production cost, environmental issues related to the usage of homogeneous catalyst and profitability in long term. One of the solutions to eliminate the problem is by utilizing low cost starting material such as palm fatty acid distillate (PFAD). PFAD is a byproduct from the refining of crude palm oil and abundantly available. Esterification of PFAD to biodiesel will be much easier with the presence of heterogeneous acid catalyst. Most of acid catalyst preparation involves series of heating process using conventional method. In this study, microwave was utilized in catalyst preparation, significantly reducing the reaction time from conventional heating method. The catalyst produced was characterized using X-Ray Diffraction (XRD), Brunauer Emmet and Teller (BET), Scanning Electron Microscopy (SEM), Temperature-Programmed Desorption - Ammonia (TPD-NH3) and Fourier Transform Infrared (FTIR) while percentage yield and conversion of the PFAD were analysed by gas chromatography - flame ionization detector (GC-FID) and acid-base titration, respectively. It has been demonstrated that the percentage yield of biodiesel from the PFAD by employing sulfonated glucose acid catalyst (SGAC) reached 98.23% under the following conditions: molar ratio of methanol to PFAD of 10:1, catalyst loading of 2.5% and reaction temperature of 70oC. The microwave-assisted SGAC showed its potential to replace the SGAC produced via conventional heating method.
    Matched MeSH terms: Microscopy, Electron, Scanning
  8. Fulltext Co-Blend Application Mode of Bulk Fill Composite Resin
    Al-Nabulsi M, Daud A, Yiu C, Omar H, Sauro S, Fawzy A, et al.
    Materials (Basel), 2019 Aug 07;12(16).
    PMID: 31394743 DOI: 10.3390/ma12162504
    Objective: To evaluate the effect of a new application method of bulk-fill flowable composite resin material on bond-strength, nanoleakage, and mechanical properties of dentine bonding agents.

    MATERIALS AND METHODS: Sound extracted human molars were randomly divided into: manufacturer's instructions (MI), manual blend 2 mm (MB2), and manual blend 4 mm (MB4). Occlusal enamel was removed and flattened, dentin surfaces were bonded by Prime & Bond universal (Dentsply and Optibond FL, Kerr). For the MI group, adhesives were applied following the manufacturer's instructions then light-cured. For MB groups, SDR flow+ bulk-fill flowable composite resin was applied in 2- or 4-mm increment then manually rubbed by a micro brush for 15 s with uncured dentine bonding agents and the mixture was light-cured. Composite buildup was fabricated incrementally using Ceram.X One, Dentsply nanohybrid composite resin restorative material. After 24-h water storage, the teeth were sectioned to obtain beams of about 0.8 mm2 for 24-h and thermocycled micro-tensile bond strength at 0.5 mm/min crosshead speed. Degree of conversion was evaluated with micro-Raman spectroscopy. Contraction gaps at 24 h after polymerization were evaluated and atomic force microscopy (AFM) nano-indentation processes were undertaken for measuring the hardness across the interface. Depth of resin penetration was studied using a scanning electron microscope (SEM). Bond strength data was expressed using two-way ANOVA followed by Tukey's test. Nanoindentation hardness was separately analyzed using one-way ANOVA.

    RESULTS: Factors "storage F = 6.3" and "application F = 30.11" significantly affected the bond strength to dentine. For Optibond FL, no significant difference in nanoleakage was found in MI/MB4 groups between baseline and aged specimens; significant difference in nanoleakage score was observed in MB2 groups. Confocal microscopy analysis showed MB2 Optibond FL and Prime & Bond universal specimens diffusing within the dentine. Contraction gap was significantly reduced in MB2 specimens in both adhesive systems. Degree of conversion (DC) of the MB2 specimens were numerically more compared to MS1 in both adhesive systems.

    CONCLUSION: Present study suggests that the new co-blend technique might have a positive effect on bond strengths of etch-and-rinse adhesives to dentine.

    Matched MeSH terms: Microscopy, Electron, Scanning
  9. Fulltext Enriched Mechanical Strength and Bone Mineralisation of Electrospun Biomimetic Scaffold Laden with Ylang Ylang Oil and Zinc Nitrate for Bone Tissue Engineering
    Mani MP, Jaganathan SK, Supriyanto E
    Polymers (Basel), 2019 Aug 08;11(8).
    PMID: 31398835 DOI: 10.3390/polym11081323
    Scaffolds supplemented with naturally derived materials seem to be a good choice in bone tissue engineering. This study aims to develop polyurethane (PU) nanofibers added with ylang ylang (YY) and zinc nitrate (ZnNO3) using the electrospinning method. Field emission scanning electron microscopy (FESEM) images showed that the diameter of the PU nanofibers (869 ± 122 nm) was reduced with the addition of YY and ZnNO3 (PU/YY-467 ± 132 nm and PU/YY/ZnNO3-290 ± 163 nm). Fourier transform infrared (FTIR), a thermal gravimetric analysis (TGA) and an X-ray diffraction (XRD) analysis confirmed the interactions between PU with YY and ZnNO3. In addition, a thermal gravimetric analysis (TGA) study revealed the improved thermal stability for PU/YY and a slight reduction in the thermal stability for PU/YY/ZnNO3. A tensile test indicated that the addition of YY and ZnNO3 (PU/YY-12.32 MPa and PU/YY/ZnNO3-14.90 MPa) improved the mechanical properties of the pristine PU (6.83 MPa). The electrospun PU/YY (524 nm) and PU/YY/ZnNO3 (284 nm) showed a reduced surface roughness when compared with the pristine PU (776 nm) as depicted in the atomic force microscopy (AFM) analysis. The addition of YY and ZnNO3 improved the anticoagulant and biocompatibility nature of the pristine PU. Furthermore, the bone mineralization study depicted the improved calcium deposition in the fabricated composites (PU/YY-7.919% and PU/YY/ZnNO3-10.150%) compared to the pristine PU (5.323%). Hence, the developed composites with desirable physico-chemical properties, biocompatibility and calcium deposition can serve as plausible candidates for bone tissue engineering.
    Matched MeSH terms: Microscopy, Electron, Scanning
  10. Fulltext Pore Structure Changes Occur During CO2 Injection into Carbonate Reservoirs
    Seyyedi M, Mahmud HKB, Verrall M, Giwelli A, Esteban L, Ghasemiziarani M, et al.
    Sci Rep, 2020 Feb 27;10(1):3624.
    PMID: 32107400 DOI: 10.1038/s41598-020-60247-4
    Observations and modeling studies have shown that during CO2 injection into underground carbonate reservoirs, the dissolution of CO2 into formation water forms acidic brine, leading to fluid-rock interactions that can significantly impact the hydraulic properties of the host formation. However, the impacts of these interactions on the pore structure and macroscopic flow properties of host rock are poorly characterized both for the near-wellbore region and deeper into the reservoir. Little attention has been given to the influence of pressure drop from the near-wellbore region to reservoir body on disturbing the ionic equilibrium in the CO2-saturated brine and consequent mineral precipitation. In this paper, we present the results of a novel experimental procedure designed to address these issues in carbonate reservoirs. We injected CO2-saturated brine into a composite core made of two matching grainstone carbonate core plugs with a tight disk placed between them to create a pressure profile of around 250 psi resembling that prevailing in reservoirs during CO2 injection. We investigated the impacts of fluid-rock interactions at pore and continuum scale using medical X-ray CT, nuclear magnetic resonance, and scanning electron microscopy. We found that strong calcite dissolution occurs near to the injection point, which leads to an increase in primary intergranular porosity and permeability of the near injection region, and ultimately to wormhole  formation. The strong heterogeneous dissolution of calcite grains leads to the formation of intra-granular micro-pores. At later stages of the dissolution, the internal regions of ooids become accessible to the carbonated brine, leading to the formation of moldic porosity. At distances far from the injection point, we observed minimal or no change in pore structure, pore roughness, pore populations, and rock hydraulic properties. The pressure drop of 250 psi slightly disturbed the chemical equilibrium of the system, which led to minor precipitation of sub-micron sized calcite crystals but due to the large pore throats of the rock, these deposits had no measurable impact on rock permeability. The trial illustrates that the new procedure is valuable for investigating fluid-rock interactions by reproducing the geochemical consequences of relatively steep pore pressure gradients during CO2 injection.
    Matched MeSH terms: Microscopy, Electron, Scanning
  11. Analysis and physicochemical properties of cellulose nanowhiskers from Pennisetum purpureum via different acid hydrolysis reaction time
    Sucinda EF, Abdul Majid MS, Ridzuan MJM, Sultan MTH, Gibson AG
    Int J Biol Macromol, 2020 Jul 15;155:241-248.
    PMID: 32240733 DOI: 10.1016/j.ijbiomac.2020.03.199
    Cellulose nanowhisker (NWC) was extracted by hydrolysing Pennisetum purpureum (PP) fibres with acid and alkali. They were subjected to different periods of acid hydrolysis; 30, 45, and 60 min. NWC morphology and physicochemical properties were characterised by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), particle size analyser, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis. NWC3, which underwent the longest hydrolysis time, showed the smallest width and length, under TEM. All samples presented a needle-like shape under TEM and AFM; uneven lengths and irregular shapes under FESEM; and a broad range of distribution, with the particle size analyser. All samples exhibited a good crystallinity index (CrI)-72.0 to 74.6%. The highest CrI% corresponded to 60 min of acid hydrolysis. Thermogravimetric analysis showed thermal stability between 310.72 °C and 336.28 °C. Thus, cellulose nanowhisker from PP fibres, have high potential as bio-nanocomposites.
    Matched MeSH terms: Microscopy, Electron, Transmission
  12. Fulltext Extraction and Characterization of Potential Biodegradable Materials Based on Dioscorea hispida Tubers
    Hazrati KZ, Sapuan SM, Zuhri MYM, Jumaidin R
    Polymers (Basel), 2021 Feb 15;13(4).
    PMID: 33672030 DOI: 10.3390/polym13040584
    This study was driven by the stringent environmental legislation concerning the consumption and utilization of eco-friendly materials. Within this context, this paper aimed to examine the characteristics of starch and fibres from the Dioscorea hispida tuber plant to explore their potential as renewable materials. The extraction of the Dioscorea hispida starch and Dioscorea hispida fibres was carried out and the chemical composition, physical, thermal, morphological properties, and crystallinity were studied. The chemical composition investigations revealed that the Dioscorea hispida starch (DHS) has a low moisture t (9.45%) and starch content (37.62%) compared to cassava, corn, sugar palm, and arrowroot starches. Meanwhile, the Dioscorea hispida fibres (DHF) are significantly low in hemicellulose (4.36%), cellulose (5.63%), and lignin (2.79%) compared to cassava, corn hull and sugar palm. In this investigation the chemical, physical, morphological and thermal properties of the Dioscorea hispida fibre and Dioscorea hispida starch were examined by chemical composition investigation, scanning electron microscopy (SEM), particle size distribution, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR), respectively. It was found that Dioscorea hispida waste is promising alternative biomass and sustainable material with excellent potential as a renewable filler material for food packaging applications.
    Matched MeSH terms: Microscopy, Electron, Scanning
  13. Fulltext Incorporation of Hydroxyapatite into Glass Ionomer Cement (GIC) Formulated Based on Alumino-Silicate-Fluoride Glass Ceramics from Waste Materials
    Wan Jusoh WN, Matori KA, Mohd Zaid MH, Zainuddin N, Ahmad Khiri MZ, Abdul Rahman NA, et al.
    Materials (Basel), 2021 Feb 18;14(4).
    PMID: 33670465 DOI: 10.3390/ma14040954
    Glass ionomer cement (GIC) is a well-known restorative material applied in dentistry. The present work aims to study the effect of hydroxyapatite (HA) addition into GIC based on physical, mechanical and structural properties. The utilization of waste materials namely clam shell (CS) and soda lime silica (SLS) glass as replacements for the respective CaO and SiO2 sources in the fabrication of alumino-silicate-fluoride (ASF) glass ceramics powder. GIC was formulated based on ASF glass ceramics, polyacrylic acid (PAA) and deionized water, while 1 wt.% of HA powder was added to enhance the properties of the cement samples. The cement samples were subjected to four different ageing times before being analyzed. In this study, the addition of HA caused an increment in density and compressive strength results along with ageing time. Besides, X-ray Diffraction (XRD) revealed the formation of fluorohydroxyapatite (FHA) phase in HA-added GIC samples and it was confirmed by Fourier Transform Infrared (FTIR) analysis which detected OH‒F vibration mode. In addition, needle-like and agglomeration of spherical shapes owned by apatite crystals were observed from Field Emission Scanning Electron Microscopy (FESEM). Based on Energy Dispersive X-ray (EDX) analysis, the detection of chemical elements in the cement samples were originated from chemical compounds used in the preparation of glass ceramics powder and also the polyacid utilized in initiating the reaction of GIC.
    Matched MeSH terms: Microscopy, Electron, Scanning
  14. Fulltext Recycling Waste Cotton Cloths for the Isolation of Cellulose Nanocrystals: A Sustainable Approach
    Mohamed SH, Hossain MS, Mohamad Kassim MH, Ahmad MI, Omar FM, Balakrishnan V, et al.
    Polymers (Basel), 2021 Feb 19;13(4).
    PMID: 33669623 DOI: 10.3390/polym13040626
    There is an interest in the sustainable utilization of waste cotton cloths because of their enormous volume of generation and high cellulose content. Waste cotton cloths generated are disposed of in a landfill, which causes environmental pollution and leads to the waste of useful resources. In the present study, cellulose nanocrystals (CNCs) were isolated from waste cotton cloths collected from a landfill. The waste cotton cloths collected from the landfill were sterilized and cleaned using supercritical CO2 (scCO2) technology. The cellulose was extracted from scCO2-treated waste cotton cloths using alkaline pulping and bleaching processes. Subsequently, the CNCs were isolated using the H2SO4 hydrolysis of cellulose. The isolated CNCs were analyzed to determine the morphological, chemical, thermal, and physical properties with various analytical methods, including attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR), field-emission scanning electron microscopy (FE-SEM), energy-filtered transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the isolated CNCs had a needle-like structure with a length and diameter of 10-30 and 2-6 nm, respectively, and an aspect ratio of 5-15, respectively. Additionally, the isolated CNCs had a high crystallinity index with a good thermal stability. The findings of the present study revealed the potential of recycling waste cotton cloths to produce a value-added product.
    Matched MeSH terms: Microscopy, Electron, Scanning
  15. Evaluation of Dimensional and Flow Properties of ExPress Glaucoma Drainage Devices
    Samsudin A, Eames I, Brocchini S, Khaw PT
    J Glaucoma, 2016 Jan;25(1):e39-45.
    PMID: 25719236 DOI: 10.1097/IJG.0000000000000243
    PURPOSE: ExPress devices are available as P50 and P200 models, the numbers related to their luminal diameters in μm. We compared their Poiseuille's Law-based theoretical resistance values with experimental values and correlated these with their luminal dimensions derived from electron microscopy.

    METHODS: Scanning electron microscopy was performed on P50 and P200 devices. Bench-top flow studies were performed to find the resistances of the devices. Devices were also incorporated into a perfused, ex vivo porcine sclera model to test and compare their control of pressure, with and without overlying scleral flaps, and with trabeculectomies.

    RESULTS: The luminal dimensions of the P200 device were 206.4±3.3 and 204.5±0.9 μm at the subconjunctival space and anterior chamber ends, respectively. Those of the P50 device were 205.0±5.8 and 206.9±3.7 μm, respectively. There were no significant differences between the P200 and P50 devices (all P>0.05). The resistances of the P200 and P50 devices were 0.010±0.001 and 0.054±0.002 mm Hg/μL/min, respectively (P<0.05). Equilibrium pressures with overlying scleral flaps were 17.81±3.30 mm Hg for the P50, 17.31±4.24 mm Hg for the P200, and 16.28±6.67 mm Hg for trabeculectomies (P=0.850).

    CONCLUSIONS: The luminal diameters of both devices are externally similar. The effective luminal diameter of the P50 is much larger than 50 μm. Both devices have low resistance values, making them unlikely to prevent hypotony on their own. They lead to similar equilibrium pressures as the trabeculectomy procedure when inserted under the scleral flap.

    Matched MeSH terms: Microscopy, Electron, Scanning
  16. Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation
    Wang YG, Hassan MD, Shariff M, Zamri SM, Chen X
    Dis Aquat Organ, 1999 Dec 22;39(1):1-11.
    PMID: 11407399
    Since 1994, white spot syndrome virus (WSSV) has been detected in cultured shrimp Penaeus monodon in Peninsular Malaysia. The gross signs, target organs and histo-cytopathology for the viral infection were studied and it was found to infect most organs and tissues including oocytes, but not hepatopancreatocytes and epithelial cells of the midgut, which were regarded as refractory tissues. Based on a time-sequence of ultrastructural cytopathology, 4 cytopathic profiles and 6 phases of viral morphogenesis were described. The virions were elliptical to short rods with trilamilar envelopes that measured 305 +/- 30 x 127 +/- 11 nm. Viral nucleosomes were often present singly in infected nuclei and were associated with the early stages of viral replication. The structure of WSSV pathognomonic white, cuticular lesions was examined at the microscopic and ultrastructural levels and the mechanism of their formation appeared to be related to the disruption of exudate transfer from epithelial cells to the cuticle via cuticular pore canals.
    Matched MeSH terms: Microscopy, Electron
  17. Fulltext Novel PVDF-PVP Hollow Fiber Membrane Augmented with TiO2 Nanoparticles: Preparation, Characterization and Application for Copper Removal from Leachate
    Abba MU, Man HC, Azis RS, Isma Idris A, Hazwan Hamzah M, Yunos KF, et al.
    Nanomaterials (Basel), 2021 Feb 04;11(2).
    PMID: 33557323 DOI: 10.3390/nano11020399
    High proportion of copper has become a global challenge owing to its negative impact on the environment and public health complications. The present study focuses on the fabrication of a polyvinylidene fluoride (PVDF)-polyvinyl pyrrolidone (PVP) fiber membrane incorporated with varying loading (0, 0.5, 1.0, 1.5, and 2.0 wt%) of titanium dioxide (TiO2) nanoparticles via phase inversion technique to achieve hydrophilicity along with high selectivity for copper removal. The developed fibers were characterized based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), permeability, porosity, zeta potential, and contact angle. The improved membrane (with 1.0 wt% TiO2) concentration recorded the maximum flux (223 L/m2·h) and copper rejection (98.18%). Similarly, 1.0 wt% concentration of TiO2 nanoparticles made the membrane matrix more hydrophilic with the least contact angle of 50.01°. The maximum copper adsorption capacity of 69.68 mg/g was attained at 1.0 wt% TiO2 concentration. The experimental data of adsorption capacity were best fitted to the Freundlich isotherm model with R2 value of 0.99573. The hybrid membrane developed in this study has considerably eliminated copper from leachate and the concentration of copper in the permeate was substantially reduced to 0.044 mg/L, which is below standard discharge threshold.
    Matched MeSH terms: Microscopy, Electron, Scanning
  18. Fulltext Effective Removal of Pb(II) Ions by Electrospun PAN/Sago Lignin-based Activated Carbon Nanofibers
    Nordin NA, Abdul Rahman N, Abdullah AH
    Molecules, 2020 Jul 06;25(13).
    PMID: 32640766 DOI: 10.3390/molecules25133081
    Heavy metal pollution, such as lead, can cause contamination of water resources and harm human life. Many techniques have been explored and utilized to overcome this problem, with adsorption technology being the most common strategies for water treatment. In this study, carbon nanofibers, polyacrylonitrile (PAN)/sago lignin (SL) carbon nanofibers (PAN/SL CNF) and PAN/SL activated carbon nanofibers (PAN/SL ACNF), with a diameter approximately 300 nm, were produced by electrospinning blends of polyacrylonitrile and sago lignin followed by thermal and acid treatments and used as adsorbents for the removal of Pb(II) ions from aqueous solutions. The incorporation of biodegradable and renewable SL in PAN/SL blends fibers produces the CNF with a smaller diameter than PAN only but preserves the structure of CNF. The adsorption of Pb(II) ions on PAN/SL ACNF was three times higher than that of PAN/SL CNF. The enhanced removal was due to the nitric acid treatment that resulted in the formation of surface oxygenated functional groups that promoted the Pb(II) ions adsorption. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. The adsorption data fitted the Langmuir isotherm and the pseudo-second-order kinetic models, indicating that the adsorption is a monolayer, and is governed by the availability of the adsorption sites. With the adsorption capacity of 588 mg/g, determined via the Langmuir isotherm model, the study demonstrated the potential of PAN/SL ACNFs as the adsorbent for the removal of Pb(II) ions from aqueous solution.
    Matched MeSH terms: Microscopy, Electron, Scanning
  19. Removal of dye waste by weak cation-exchange nanofiber membrane immobilized with waste egg white proteins
    Pakalapati H, Show PL, Chang JH, Liu BL, Chang YK
    Int J Biol Macromol, 2020 Dec 15;165(Pt B):2494-2507.
    PMID: 33736272 DOI: 10.1016/j.ijbiomac.2020.10.099
    In this research, a protein nanofiber membrane (P-COOH-CEW) was developed to treat the dye waste. Initially, polyacrylonitrile nanofiber membrane (PAN) was prepared by electrospinning, followed by heat treatment, alkaline treatment, and neutralization to obtain weak cation exchange nanofiber membrane (P-COOH). The P-COOH membrane was chemically coated with chicken egg white (CEW) proteins to obtain a 3D structure of complex protein nanofiber membrane (P-COOH-CEW). The composite prepared was characterized with Fourier Transform Infrared analysis (FTIR), Scanning Electron Microscopy (SEM), and thermogravimetric analysis (TGA). Further, the composite was evaluated by investigating the removal of Toluidine Blue O (TBO) from aqueous solutions in batch conditions. Different operating parameters - coupling of CEW, shaking rate, initial pH, contact time, temperature, and dye concentration were studied. From the results, maximum removal capacity and equilibrium association constant was determined to be 546.24 mg/g and 10.18 mg/mg, respectively at pH 10 and 298 K. The experimental data were well fitted to pseudo-second order model. Furthermore, desorption studies revealed that the adsorbed TBO can be completely eluted by using 50% ethanol or 50% glycerol in 1 M NaCl solution. Additionally, the reuse of P-COOH-CEW membrane reported to have 97.32% of removal efficiency after five consecutive adsorption/desorption cycles.
    Matched MeSH terms: Microscopy, Electron, Scanning
  20. Visualization of Bacteria-Mediated Gene Delivery Using High-Resolution Electron and Confocal Microscopy
    Osahor AN, Ng AWR, Narayanan K
    Methods Mol Biol, 2021;2211:29-40.
    PMID: 33336268 DOI: 10.1007/978-1-0716-0943-9_3
    Visual analysis of the gene delivery process when using invasive bacteria as a vector has been conventionally performed using standard light and fluorescence microscopy. These microscopes can provide basic information on the invasiveness of the bacterial vector including the ability of the vector to successfully adhere to the cell membrane. Standard microscopy techniques however fall short when finer details including membrane attachment as well as internalization into the cytoplasm are desired. High-resolution visual analysis of bacteria-mediated gene delivery can allow accurate measurement of the adherence and internalization capabilities of engineered vectors. Here, we describe the use of scanning electron microscopy (SEM) to directly quantify vectors when they are external to the cell wall, and confocal microscopy to evaluate the vectors when they have internalized into the cytoplasm. By performing the invasion procedure on microscope coverslips, cells can be easily prepared for analysis using electron or confocal microscopes. Imaging the invasion complexes in high resolution can provide important insights into the behavior of bacterial vectors including E. coli, Listeria, and Salmonella when invading their target cells to deliver DNA and other molecules.
    Matched MeSH terms: Microscopy, Electron, Scanning
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