scholarly journals Assessing the hyperthermic properties of magnetic heterostructures: the case of gold–iron oxide composites

2016 ◽  
Vol 6 (6) ◽  
pp. 20160058 ◽  
Author(s):  
Elvira Fantechi ◽  
Paula M. Castillo ◽  
Erika Conca ◽  
Francesca Cugia ◽  
Claudio Sangregorio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Magnetic Fluid ◽  
Potassium Citrate ◽  
Alternating Magnetic Field ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Magnetic Fluid Hyperthermia ◽  
Transmission Electron ◽  
Oxide Composites

Gold–iron oxide composites were obtained by in situ reduction of an Au(III) precursor by an organic reductant (either potassium citrate or tiopronin) in a dispersion of preformed iron oxide ultrasmall magnetic (USM) nanoparticles. X-ray diffraction, transmission electron microscopy, chemical analysis and mid-infrared spectroscopy show the successful deposition of gold domains on the preformed magnetic nanoparticles, and the occurrence of either citrate or tiopronin as surface coating. The potential of the USM@Au nanoheterostructures as heat mediators for therapy through magnetic fluid hyperthermia was determined by calorimetric measurements under sample irradiation by an alternating magnetic field with intensity and frequency within the safe values for biomedical use. The USM@Au composites showed to be active heat mediators for magnetic fluid hyperthermia, leading to a rapid increase in temperature under exposure to an alternating magnetic field even under the very mild experimental conditions adopted, and their potential was assessed by determining their specific absorption rate (SAR) and compared with the pure iron oxide nanoparticles. Calorimetric investigation of the synthesized nanostructures enabled us to point out the effect of different experimental conditions on the SAR value, which is to date the parameter used for the assessment of the hyperthermic efficiency.

scholarly journals Effect of Alternating Magnetic Field on the Fatigue Behaviour of EN8 Steel and 2014-T6 Aluminium Alloy

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 984 ◽  
Author(s):  
Akram ◽  
Babutskyi ◽  
Chrysanthou ◽  
Montalvão ◽  
Pizurova
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Fatigue Behaviour ◽  
Alternating Magnetic Field ◽  
X Ray Diffraction ◽  
Secondary Precipitation ◽  
Transmission Electron ◽  
Fatigue Endurance ◽  
Fracture Features ◽  
Compressive Residual Stresses

The application of an alternating magnetic field (0.54 T) was observed to lead to an improvement in the fatigue endurance and an increase in Vickers microhardness and tensile strength of both EN8 steel and AA2014-T6 alloy. Fractography using scanning electron microscopy showed evidence of more ductile fracture features after treatment in contrast to untreated samples. The results of X-ray diffraction indicated formation of more compressive residual stresses following treatment; while examination by transmission electron microscopy showed evidence of fewer dislocations. In the case of the AA2014-T6 alloy; Guinier-Preston (GP) zones were also generated by the alternating magnetic field. However; the temperature increase during the treatment was too low to explain these observations. The results were attributed to the non-thermal effect of the alternating magnetic field treatment that led to depinning and movement of dislocations and secondary precipitation of copper.

On the in Vitro Hyperthermia of Magnetic Fluid in AC Magnetic Field

2009 ◽  
Author(s):  
Junfeng Jiang ◽  
Ruoyu Hong ◽  
Xiaohui Zhang ◽  
Hongzhong Li
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Volume Fraction ◽  
Maximum Temperature ◽  
Magnetic Fluid Hyperthermia ◽  
Ac Magnetic Field ◽  
Hyperthermia Therapy ◽  
Good Biocompatibility ◽  
High Chemical Stability

Hyperthermia therapy for cancer has attracted much attention nowadays. The study on the heat transfer in the magnetic fluid and the tumor is crucial for the successful application of magnetic fluid hyperthermia (MFH). Water-based Fe3O4 magnetic fluid is expected to be a most appropriate candidate for MFH due to the good biocompatibility, high saturation magnetization, super-paramagnetization and high chemical stability. In this paper, we explore the heat generation and transfer in magnetic fluid which is placed under an AC magnetic field. It is found that the amplitude and the frequency of alternating magnetic field, particle size and volume fraction have a pronounce influence on maximum temperature of hyperthermia.

scholarly journals 138 Responses of Micro Magnetic Fluid Bridge Held by Two Small Magnets in Alternating Magnetic Field

2013 ◽  
Vol 2013.48 (0) ◽  
pp. 78-79
Author(s):  
Hiroki TAKAMATSU ◽  
Seiichi SUDO ◽  
Hidemasa TAKANA ◽  
Hideya NISHIYAMA
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Alternating Magnetic Field

scholarly journals Effect of Tetramethylammonium Hydroxide on Nucleation, Surface Modification and Growth of Magnetic Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Ângela L. Andrade ◽  
José D. Fabris ◽  
José D. Ardisson ◽  
Manuel A. Valente ◽  
José M. F. Ferreira
Keyword(s):  
Zeta Potential ◽  
Magnetite Nanoparticles ◽  
Heat Dissipation ◽  
Tetramethylammonium Hydroxide ◽  
Precipitation Method ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Magnetite Particles

Nanoparticles of magnetite (Fe3O4) were obtained by reacting ferric chloride with sodium sulphite, through the reduction-precipitation method. The effects of adding tetramethylammonium hydroxide (TMAOH) during or after the precipitation of the iron oxide were studied in an attempt to obtain well-dispersed magnetite nanoparticles. Accordingly, the following experimental conditions were tested: (i) precipitation in absence of TMAOH (sample Mt), (ii) the same as (i) after peptizing with TMAOH (Mt1), (iii) TMAOH added to the reaction mixture during the precipitation of magnetite (Mt2). Analyses with transmission electron microscopy (TEM), X-ray diffraction, Mössbauer spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), zeta potential, and magnetization measurements up to 2.5 T revealed that magnetite was normally formed also in the medium containing TMAOH. The degree of particles agglomeration was monitored with laser diffraction and technique and inspection of TEM images. The relative contributions of Néel and Brownian relaxations on the magnetic heat dissipation were studied by investigating the ability of suspensions of these magnetite nanoparticles to release heat in aqueous and in hydrogel media. Based on ATR-FTIR and zeta potential data, it is suggested that the surfaces of the synthesized magnetite particles treated with TMAOH become coated with (CH3)4N+cations.

scholarly journals Biomass-Derived Activated Carbon as a Catalyst for the Effective Degradation of Rhodamine B dye

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
High Specific Surface Area ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.

526 MAGNETIC FINE NEEDLES AND IRON OXIDE PARTICLES IN AN ALTERNATING MAGNETIC FIELD FOR HEPATOMA TREATMENT

2009 ◽  
Vol 50 ◽  
pp. S195-S196
Author(s):  
J.R. Zuchini ◽  
C.H. Huang ◽  
S.C. Huang ◽  
Y.H. Shih ◽  
H.W. Tsai ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Alternating Magnetic Field ◽  
Iron Oxide Particles ◽  
Oxide Particles

Superconductivity of Dc Reactive Magnetron Sputtered Epitaxial TiN/NbN Superlattices

1992 ◽  
Vol 275 ◽  
Author(s):  
M. Shinn ◽  
B. -S. Hong ◽  
S. A. Barnett
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Surface ◽  
Wavelength Dependence ◽  
Reactive Magnetron ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ABSTRACTEpitaxial B1-structure TiN/NbN superlattices have been grown by reactive magnetron sputtering On MgO(001). X-ray diffraction and transmission electron microscopy (TEM) diffraction spectra exhibited up to nine orders of superlattice reflections, indicating that the superlattice interfaces were relatively sharp. TEM images also showed well-defined layers. The superlattice wavelength (∧) dependence of the superconducting transition temperature (Tc), critical Current density (Jc), and electrical resistivity (ρ) have been investigated. Tc values increased from 12 K to 17 K with increasing ∧. Jc in a magnetic field perpendicular to the film surface ranged from 104 to 106 A/cm2, increasing with increasing wavelength and decreasing with increasing applied magnetic field. Jc in a field parallel to the film surface was > 10 times higher, ≈ 107 A/cm2. The resistivity exhibited different ∧ dependencies in three different A ranges.

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