scholarly journals Ultrasound Imaging and Antithrombotic Effects of PLA-Combined Fe3O4-GO-ASA Multifunctional Nanobubbles

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Zhang ◽  
Zheng Liu ◽  
Cunyi Chang ◽  
Ming Hu ◽  
Yang Teng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Double Emulsion ◽  
Spherical Shape ◽  
Magnetic Targeting ◽  
Solvent Evaporation Method ◽  
Antithrombotic Effects ◽  
Prepared Composite ◽  
The Magnetic Field ◽  
Regular Spherical Shape

PLA-combined ferroferric oxide–graphene oxide–aspirin (Fe3O4-GO-ASA) multifunctional nanobubbles were prepared using the double emulsion-solvent evaporation method. The obtained composite nanobubbles had a regular spherical shape, Zeta potential of (−36.5 ± 10.0) mV, and particle size distribution range of 200–700 nm. The experimental results showed that PLA-combined Fe3O4-GO-ASA nanobubbles could effectively improve the antithrombin parameters of PT, TT, APTT, and INR, and significantly inhibit thrombosis when the composite nanobubbles with a concentration of 80 mg·mL−1 interacted with the rabbit blood. The prepared composite nanobubbles could reach a significant ultrasonic imaging effect and good magnetic targeting under the magnetic field when the nanobubbles' concentration was only 60 mg·mL−1.

MAGNETIZED ROTATING NEUTRON STARS SIMULATED BY GENERAL-RELATIVISTIC POLYTROPIC MODELS: THE NUMERICAL TREATMENT

2011 ◽  
Vol 22 (10) ◽  
pp. 1107-1137
Author(s):  
V. S. GEROYANNIS ◽  
A. G. KATELOUZOS ◽  
F. N. VALVI
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Liouville Problem ◽  
Spherical Shape ◽  
Rotation Periods ◽  
Prolate Shape ◽  
Shafranov Equation ◽  
General Relativistic ◽  
Sturm Liouville ◽  
The Magnetic Field

We compute general-relativistic polytropic models of magnetized rotating neutron stars, assuming that magnetic field and rotation can be treated as decoupled perturbations acting on the nondistorted configuration. Concerning the magnetic field, we develop and apply a numerical method for solving the relativistic Grad–Shafranov equation as a nonhomogeneous Sturm–Liouville problem with nonstandard boundary conditions. We present significant geometrical and physical characteristics of six models, four of which are models of maximum mass. We find negative ellipticities owing to a magnetic field with both toroidal and poloidal components; thus the corresponding configurations have prolate shape. We also compute models of magnetized rotating neutron stars with almost spherical shape due to the counterbalancing of the rotational effect (tending to yield oblate configurations) and the magnetic effect (tending in turn to derive prolate configurations). In this work such models are simply called "equalizers." We emphasize on numerical results related to magnetars, i.e. ultramagnetized neutron stars with relatively long rotation periods.

scholarly journals FORMULATION AND EVALUATION OF ISORHAMNETIN LOADED POLY LACTIC-CO-GLYCOLIC ACID NANOPARTICLES

2017 ◽  
Vol 10 (11) ◽  
pp. 177
Author(s):  
Kandakumar Settu ◽  
Manju Vaiyapuri
Keyword(s):  
Particle Size ◽  
Glycolic Acid ◽  
Polymeric Nanoparticles ◽  
Double Emulsion ◽  
Spherical Shape ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Characteristic Variety ◽  
Sem Image ◽  
Flexible Technology

  Objective: The aim of the present study was formulation and evaluation of isorhamnetin loaded poly lactic-co-glycolic acid (PLGA) polymeric nanoparticles (NPs).Methods: The present study was designed to incorporate the isorhamnetin in PLGA formulation by double emulsion solvent evaporation method, which offers a dynamic and flexible technology for enhancing drug solubility due to their biphasic characteristic, variety in design, composition and assembly. Synthesized isorhamnetin-PLGA NPs were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and particle size analyzer. We tested the efficacy of isorhamnetin-PLGA NPs in HepG2 cell lines.Results: From the FTIR result, we concluded that -C-N-, -C=C-, N-H, C-N, N-O, O-H, and C-H are the functional groups present in isorhamnetin-PLGA NPs, SEM image shows spherical shape of particles. The particle size analysis result shows 255-342 nm range of particles. Isorhamnetin-PLGA NPs significantly enhanced (p<0.05) the antiproliferative effect when compared to the plain drug.Conclusion: This study concluded that the newly formulated NP drug delivery systems of isorhamnetin provided an insight into the therapeutic effectiveness of the designed formulation for the treatment of chemotherapy.

scholarly journals Synthesis, sintering, specific heat and magnetism of Eu3S4 by low-temperature CS2-gas sulfurization of Eu2O3 nanospheres

2018 ◽  
Vol 36 (4) ◽  
pp. 616-622
Author(s):  
Yuqi Chen ◽  
Liang Li ◽  
Shinji Hirai
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Specific Heat ◽  
Single Phase ◽  
Primary Particle ◽  
Anomalous Behavior ◽  
Primary Particle Size ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Magnetic Field

AbstractSingle-phase Eu3S4 was obtained via CS2 gas sulfurization of Eu2O3 nanospheres at 773 K for longer than 0.5 h. The primary particle size of Eu3S4 became larger than that of Eu2O3 during the sulfurization process. Pure synthetic Eu3S4 powders were unstable and transformed to EuS at 873 K under vacuum. Eu3S4 compacts were sintered in temperature range of 773 K to 1173 K and they transformed to EuS at 1473 K during spark plasma sintering. Specific heat of sintered Eu3S4 did not show an anomalous behavior in the range of 2 K to 50 K. The magnetic susceptibility of polycrystalline Eu3S4 followed a Curie-Weiss law from 2 K to 300 K. Magnetization of polycrystalline Eu3S4 was larger than that of single crystal Eu3S4 when the magnetic field was less than 3.5 kOe.

Influence of the Particle Size on the Rheology of Magnetorheological Elastomer

2014 ◽  
Vol 809-810 ◽  
pp. 757-763 ◽  
Author(s):  
Qian Jin ◽  
Yong Gang Xu ◽  
Yang Di ◽  
Hao Fan
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Theoretical Analysis ◽  
Shear Modulus ◽  
Rheological Properties ◽  
Optimum Size ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Effect ◽  
The Relationship ◽  
The Magnetic Field

In this paper, the correlation between the particle size and rheological properties of MRE was discussed through both experimental results and theoretical analysis. It shows that the particle size can significantly influence the magnetorheological effect by changing the initial shear modulus and the saturated magnetic-induced shear modulus . With an increase in the particle size, the initial shear modulus gets lower, and the saturated magnetic-induced shear modulus increases to the maximum and then decreases. The larger the particle size is, the longer the distance between neighbor particles along the magnetic field is. Based on the relationship between the particle size and shear modulus, there exists an optimum size for added particles. Moreover, the performance of MRE can be improved by optimizing the particle size based on those rules.

Experimental Validation of Numerical Methods of MRE Simulations

2009 ◽  
Vol 154 ◽  
pp. 113-120
Author(s):  
Wiesław Szymczyk ◽  
Anna Boczkowska ◽  
Tadeusz Niezgoda ◽  
Konrad Zubko
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Spherical Shape ◽  
Material Model ◽  
Resin Matrix ◽  
3D Fem ◽  
Magnetic Dipoles ◽  
Mechanical Coupling ◽  
Active Vibration Damping ◽  
The Magnetic Field

This paper deals with the development of magnetoactive elastomers (MREs) based on the carbonyl iron particles-filled polyurethane resin. Their stiffness can be changed easily by magnetic field. Such a property can be useful in construction of active vibration damping structural elements. For the needs of numerical modelling methods validation the elementary case of the two magnetic particles was investigated experimentally. Special “macro samples” were prepared with pairs of ferromagnetic particles of spherical shape of diameter of 12.7 mm. They provided easy observations and measurements. The gap distance between particles was established on the level of ¼ of the diameter. After application of the magnetic field particles started to attract each other like magnetic dipoles. The mutual displacement of the dipoles was recorded in function of the magnetic field intensity, which was varied in the range100÷300 [mT]. The deformation field was also obtained from the digital image processing (DIC). Then the experiment was simulated numerically with the use of the 3D FEM models. The dipoles were loaded by forces which were increased gradually until displacements reached values that were measured experimentally. Calculations were performed on the MSC Patran-MARC platform. The Neo-Hookean material model was used to describe properties of the resin matrix. Magneto-mechanical coupling was taken into consideration with the use of an iterative method. The results of calculations were compared with the experimental results. The validation of the base modelling concept was successfully completed.

Journal Bearing Stiffness and Damping Coefficients Using Nanomagnetorheological Fluids and Stability Analysis

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
D. A. Bompos ◽  
P. G. Nikolakopoulos
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Dynamic Characteristics ◽  
Apparent Viscosity ◽  
Magnetic Field Intensity ◽  
Journal Bearing ◽  
Damping Coefficients ◽  
Mr Fluids ◽  
Stiffness And Damping ◽  
The Magnetic Field

The integrity and reliability of a rotor depend significantly on the dynamic characteristics of its bearings. Bearing design has evolved in many ways in order to achieve higher damping and stiffness. A promising field in terms of vibrations control and overall performance improvement for the journal bearings is the use of smart lubricants. Smart lubricants are fluids with controllable properties. A suitable excitation, such as an electric or a magnetic field, is applied to the lubricant volume and changes its properties. Magnetorheological (MR) fluids consist one category of lubricants with controllable properties. Magnetic particles inside the MR fluid volume are coerced by a magnetic field. These particles form chains which hinder the flow of the base fluid and alter its apparent viscosity. According to the magnetic particle size, there are two subcategories of magnetorheological fluids: the regular MR fluids with particles sizing some tens of micrometers and the nanomagnetorheological (NMR) fluids with a particle size of a few nanometers. The change of magnetorheological fluid's viscosity is an efficient way of control of the dynamic characteristics of the journal bearing system. In this work, the magnetic field intensity inside the volume of lubricant is calculated through finite element analysis. The calculated value of the magnetic field intensity is used to define the apparent viscosity of both the MR and the NMR fluids. Using computational fluid dynamics (CFD) method, the pressure developed inside the journal bearing is found. Through this simulation with the use of a suitable algorithm, the stiffness and damping coefficients are calculated and stability charts of Newtonian, MR, and NMR fluid are presented and discussed.

Stabilization of fluidized beds of particles magnetized by an external field: effects of particle size and field orientation

2013 ◽  
Vol 732 ◽  
pp. 282-303 ◽  
Author(s):  
M. J. Espin ◽  
J. M. Valverde ◽  
M. A. S. Quintanilla
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Magnetic Fields ◽  
Yield Stress ◽  
Fluidized Beds ◽  
Gas Flow ◽  
Magnetic Contribution ◽  
Field Orientation ◽  
Jamming Transition ◽  
The Magnetic Field

AbstractThis paper reports experimental measurements on the yield stress, the permeability to gas flow and the gas velocity at the jamming transition of gas-fluidized beds of magnetizable particles as affected by particle size and orientation and strength of an externally imposed magnetic field. Tested samples consisted of relatively monodisperse magnetite powders of $35$, $50$ and $65~\unicode[.5,0][STIXGeneral,Times]{x03BC} \mathrm{m} $ particle size. The permeability to gas flow and jamming transition velocity increase with particle size and in a specially marked way when the magnetic field is applied along the gas flow direction. The magnetic contribution to the yield stress is also particularly enhanced for co-flow magnetic fields. However, the effect of particle size on the yield stress shows a dependence on the microstructure packing as affected by particle size and orientation of the field. The magnetic yield stress increases with particle size for magnetic fields applied in the cross-flow configuration while the opposite trend is observed when the direction of the magnetic field is parallel to the gas flow. The observations reported in this paper are generally explained by the formation of chains of particles due to attractive magnetic forces between the magnetized particles and the orientation of these chains with respect to the magnetic field.

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