scholarly journals Dynamic Response of Polyindole Coated Zinc Ferrite Particle Suspension under an Electric Field

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 101
Author(s):  
Su Hyung Kang ◽  
Hyoung Jin Choi
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Electric Fields ◽  
Magnetic Particles ◽  
Chemical Characterization ◽  
Spherical Shape ◽  
Ferrite Particle ◽  
Transmission Electron ◽  
Electric And Magnetic Fields ◽  
Er Fluid

ZnFe2O4 particles initially synthesized through a simple solvothermal method were coated using polyindole (PIn) to prepare an actively controllable core-shell typed hybrid material under both electric and magnetic fields. An advantage of this process is not needing to add the stabilizers or surfactants commonly used for uniform coating when synthesizing core or shell-structured particles. The synthesized ZnFe2O4/PIn particles have a lower density than conventional magnetic particles and have suitable properties as electrorheological (ER) particles. The expected spherical shape of the particles was proven using both scanning electron microscopy and transmission electron microscopy. The chemical characterization was performed using Fourier-transform infrared spectroscopy and X-ray diffraction analysis. To analyze the rheological properties, a ZnFe2O4/PIn based suspension was prepared, and dynamic rheological measurements were performed for different electric field strengths using a rotary rheometer. Both dynamic and elastic yield stresses of the ER fluid had a slope of 1.5, corresponding to the conductivity model. Excellent ER effect was confirmed through rheological analysis, and the prepared ER fluid had a reversible and immediate response to repeated electric fields.

Ultrastructural changes in Staphylococcus aureus treated with pulsed electric fields / Cambios ultraestructurales en Staphylococcus aureus sometida a campos eléctricos pulsantes

1997 ◽  
Vol 3 (2) ◽  
pp. 113-121 ◽  
Author(s):  
U.R. Pothakamury ◽  
G.V. Barbosa-Cánovas ◽  
B.G. Swanson ◽  
K.D. Spence
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Electric Field ◽  
Electric Fields ◽  
Untreated Control ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
Treat Ment

Early stationary phase cells of Staphylococcus aureus were inoculated into a model food, simulated milk ultrafiltrate (SMUF) and subjected to 16, 32, and 64 pulses at electric field intensities of 20, 40 and 60 kV/cm at 13 °C. In addition temperatures of 20, 25 and 30 °C were also tested with 32 pulses and an electric field of 60 kV/cm. The temperature of the SMUF increased by 1-2 ° C at the end of the 64 pulses. Cells subjected to 64 pulses at 20, 40 and 60 kV/cm were observed for ultrastructural changes using scanning and transmission electron microscopy techniques. The cell surface was rough after treatment with electric field when observed by scanning electron microscopy (SEM). The cell wall was broken, and the cytoplasmic contents were leaking out of the cell after exposure to 64 pulses at 60 kV/cm when observed by transmission electron microscopy (TEM). The breaking of the cell wall is an indication of electro-mechanical breakdown of the cell. The increase in inactivation with an increase in the electric field strength can be related to the increase in the damage to the cells. Cells subjected to 32 pulses at 60 kV/cm and 13, 20 or 25 °C were compared microscopically with the untreated control cells. Cells subjected to heat treat ment (10 min, at 66 °C) were compared with electric field-treated and untreated control cells. Although important changes were observed in the protoplast, no cell wall breakdown was observed in heat-treated cells when compared to the electric field-treated cells. This result indi cates a different mechanism of inactivation of cells with heat treatment.

scholarly journals In situ Transmission Electron Microscopy Studies of Electric-field-induced Phenomena in Ferroelectrics

2005 ◽  
Vol 20 (7) ◽  
pp. 1641-1653 ◽  
Author(s):  
Xiaoli Tan ◽  
Hui He ◽  
Jian-Ku Shang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Domain Wall ◽  
Electric Field ◽  
Single Crystal ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Transmission Electron ◽  
High Electric Fields

High electric fields were delivered to specimens during imaging in the transmission electron microscopy (TEM) chamber to reveal details of electric field-induced phenomena in ferroelectric oxides. These include the polarization switching in nanometer-sized ferroelectric domains and the grain boundary cavitation in a commercial lead zirconate titanate (PZT) polycrystalline ceramic, the domain wall fracture in a Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal, and the transformation of incommensurate modulations in Pb0.99Nb0.02[(Zr1−xSnx)1−yTiy]0.98O3 (PZST100x/100y/2) polycrystalline ceramics. In the PZT ceramic, a cavitation process was uncovered for the electric field-induced intergranular fracture. In the ferroelectric single crystal, a preexisting crack was observed to deflect and to follow a 90° domain wall, indicating the presence of severe incompatible piezoelectric strains at thedomain wall. In the antiferroelectric PZST ceramics, the electric field-induced antiferroelectric-to-ferroelectric phase transformation was accompanied with the disappearance of incommensurate modulations.

Auger Electron Spectroscopy and Its Application to Nanotechnology

2011 ◽  
Vol 19 (2) ◽  
pp. 12-15 ◽  
Author(s):  
S. N. Raman ◽  
D. F. Paul ◽  
J. S. Hammond ◽  
K. D. Bomben
Keyword(s):  
Electron Microscopy ◽  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Imaging Techniques ◽  
Chemical Characterization ◽  
Depth Resolution ◽  
Surface Modifications ◽  
Transmission Electron ◽  
Nanoscale Characterization

Over the past decade, the field of nanotechnology has expanded, and the most heavily used nanoscale characterization/imaging techniques have been scanning probe microscopy (SPM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Although these high-resolution imaging techniques help visualize nanostructures, it is essential to understand the chemical nature of these materials and their growth mechanisms. Surface modifications in the first few nanometers can alter the bulk properties of these nanostructures, and conventional characterization techniques, including energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS) associated with SEM and TEM are not suited to detecting these surface modifications except in special, favorable specimens. A modern state-of-the-art scanning Auger electron spectroscopy (AES) instrument provides valuable elemental and chemical characterization of nanostructures with a lateral spatial resolution better than 10 nm and a depth resolution of a few nm. In this article we review the technique of scanning AES and highlight its unique analytical capabilities in the areas of nanotechnology, metallurgy, and semiconductors.

scholarly journals Synthesize and Characterization of Hollow Boron-Nitride Nanocages

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
W. S. Zhang ◽  
J. G. Zheng ◽  
W. F. Li ◽  
D. Y. Geng ◽  
Z. D. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Boron Nitride ◽  
Growth Mechanism ◽  
Spherical Shape ◽  
Amorphous Boron ◽  
Transmission Electron ◽  
Ammonia Atmosphere

The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed.

Calorimetric Analysis of Precipitation in Undercooled Ni-Si Alloy

2013 ◽  
Vol 307 ◽  
pp. 352-357
Author(s):  
Kai Fan ◽  
Feng Liu ◽  
Bao Quan Fu ◽  
Wen Zhong Luo ◽  
Yao He Zhou
Keyword(s):  
Electron Microscopy ◽  
Exothermic Reaction ◽  
Spherical Shape ◽  
Precipitate Size ◽  
Precipitation Process ◽  
Calorimetric Analysis ◽  
Shape Model ◽  
Transmission Electron ◽  
Isothermal Measurements ◽  
Good Agreement

In order to study the precipitaion of Ni3Si particle in undercooled Ni-Si alloy, calorimetric analyses were carried out using non-isothermal measurements by DSC. The scanning electron microscopy (SEM) and the transmission electron microscopy (TEM) measurements were used to describe qualitatively and quantitatively the precipitate microstructures. The non-isothermal DSC thermograms exhibited one reaction peaks and it indicated that the precipitation process is an exothermic reaction. The evolution for the precipitate was obtained in the as-solidified Ni-Si alloy subjected to DT=195K, meanwhile, the precipitate size was found increased with decreased heating rate in the TEM images. The largest precipitate size was about 120nm, and the precipitates still kept spherical shape. Model prediction for the precipitation of Ni3Si particle has been performed. Good agreement with experimental data has been achieved

scholarly journals A novel technique to synthesis of tenorite (CuO) nanoparticles from low concentration CuSO4 solution

2011 ◽  
Vol 47 (1) ◽  
pp. 73-78 ◽  
Author(s):  
E. Darezereshki ◽  
F. Bakhtiari
Keyword(s):  
Electron Microscopy ◽  
Decomposition Method ◽  
Raw Materials ◽  
Spherical Shape ◽  
Cuo Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Decomposition Method ◽  
Novel Technique ◽  
Transmission Electron

In this study CuO nanoparticles were prepared via direct thermal decomposition method using basic copper sulphates as wet chemically synthesized precursor which was calcined in air at 750?C for 2h. Samples were characterized by thermogravimetric (TG-DSC), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), infrared spectrum (IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD, EDS, and IR results indicated that the synthesized CuO particles were pure. The SEM and TEM results showed that the CuO nanoparticles were of approximate spherical shape, and 170?5 nm in size. Using this method, Cuo nanoparticles could be produced without using organic solvent, expensive raw materials, and complicated equipment.

scholarly journals Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 263 ◽  
Author(s):  
Maria Letizia Manca ◽  
Iris Usach ◽  
José Esteban Peris ◽  
Antonella Ibba ◽  
Germano Orrù ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Yeast Cells ◽  
Unilamellar Vesicles ◽  
Transmission Electron ◽  
Physico Chemical

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

Supramolecular chemistry at interfaces: host-guest interactions for attaching PEG and 5-fluorouracil to the surface of porous nanosilica

2016 ◽  
Vol 5 (6) ◽  
Author(s):  
Tuong Vi Tran ◽  
Uyen Vy Vo ◽  
Dong Yen Pham ◽  
Dai Lam Tran ◽  
Thi Hiep Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Cell Proliferation ◽  
Polyethylene Glycol ◽  
Inclusion Complex ◽  
Spherical Shape ◽  
Burst Release ◽  
Anticancer Drug Delivery ◽  
Transmission Electron

AbstractPorous nanosilica (PNS) has been attracting much attention in fabrication of nanocarriers for a drug delivery system (DDS). However, the unmodified PNS-based carriers exhibited a significant initial burst release of drug, which may limit their potential clinical application. In this study, PNS was surface conjugated with cyclodextrin (CD) which was functionalized with adamantylamine-polyethylene glycol (APEG) for 5-fluorouracil (5-FU) delivery, in which case CD was used due to its ability to form a stable inclusion complex with 5-FU and APEG. The conjugated PNS (PNSC@APEG) was successfully prepared with spherical shape and diameter around 50 nm, determined by transmission electron microscopy (TEM). In addition, 5-FU was efficiently trapped in PNSC@APEG particles, which were around 63.4%±3.8% and was slowly released up to 3 days in phosphate buffer saline (PBS). Furthermore, the cell proliferation kit I (MTT) assay data showed that PNSC@APEG was a biocompatible nanocarrier. These results indicated that PNSC@APEG nanoparticles have a great potential as novel carriers for anticancer drug delivery.

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