Two-dimensional EPR imaging with the rapid scan and rotated magnetic field gradient

2014 ◽  
Vol 248 ◽  
pp. 126-130 ◽  
Author(s):  
T. Czechowski ◽  
W. Chlewicki ◽  
M. Baranowski ◽  
K. Jurga ◽  
P. Szczepanik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Two Dimensional ◽  
Rapid Scan

Two-dimensional spectral–spatial EPR imaging with the rapid scan and modulated magnetic field gradient

2014 ◽  
Vol 243 ◽  
pp. 1-7 ◽  
Author(s):  
T. Czechowski ◽  
W. Chlewicki ◽  
M. Baranowski ◽  
K. Jurga ◽  
P. Szczepanik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Two Dimensional ◽  
Rapid Scan

Effects of Magnetic Field Gradient on Particle Distributions of Suspension Comprised of both Magnetic and Nonmagnetic Particles Using Two-Dimensional Monte Carlo Simulations

2009 ◽  
Vol 79-82 ◽  
pp. 1301-1304
Author(s):  
Xiao Ling Peng ◽  
Mi Yan ◽  
Hong Liang Ge
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Magnetic Fields ◽  
Monte Carlo Simulations ◽  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Slip Casting ◽  
Functionally Graded ◽  
Two Dimensional ◽  
Nonmagnetic Particles

Functionally graded materials (FGMs) have recently been fabricated under gradient magnetic fields via slip casting, based on the distinct difference in magnetic susceptibility between the components in a suspension comprised of both magnetic particles (MPs) and nonmagnetic particles (NPs). In this work, a physical model of a mixed suspension comprised of both MPs and NPs under a gradient magnetic field is built, base on which the distributions of particles in the suspension under gradient magnetic fields are studied using two-dimensional Monte Carlo simulations, and the effects of magnetic field gradient on the distributions of particles are investigated. The results show that a gradient distribution of MPs is formed along field direction, which is attributed to the translation of MPs. As the magnetic field gradient is increased, the distribution gradient of MPs increases.

Spectroscopic imaging of human disease

1996 ◽  
Vol 54 ◽  
pp. 884-885
Author(s):  
D.J. Meyerhoff
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Human Disease ◽  
Morphological Changes ◽  
Magnetic Field Gradient ◽  
Spectroscopic Imaging ◽  
Resonance Spectroscopy ◽  
Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

scholarly journals Magnetic hybrid materials interact with biological matrices

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Christine Gräfe ◽  
Elena K. Müller ◽  
Lennart Gresing ◽  
Andreas Weidner ◽  
Patricia Radon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
Hybrid Materials ◽  
Biomedical Application ◽  
Magnetic Field Gradient ◽  
Apical Cell ◽  
Cell Type ◽  
Cell Layers ◽  
Barrier Model

Abstract Magnetic hybrid materials are a promising group of substances. Their interaction with matrices is challenging with regard to the underlying physical and chemical mechanisms. But thinking matrices as biological membranes or even structured cell layers they become interesting with regard to potential biomedical applications. Therefore, we established in vitro blood-organ barrier models to study the interaction and processing of superparamagnetic iron oxide nanoparticles (SPIONs) with these cellular structures in the presence of a magnetic field gradient. A one-cell-type–based blood-brain barrier model was used to investigate the attachment and uptake mechanisms of differentially charged magnetic hybrid materials. Inhibition of clathrin-dependent endocytosis and F-actin depolymerization led to a dramatic reduction of cellular uptake. Furthermore, the subsequent transportation of SPIONs through the barrier and the ability to detect these particles was of interest. Negatively charged SPIONs could be detected behind the barrier as well as in a reporter cell line. These observations could be confirmed with a two-cell-type–based blood-placenta barrier model. While positively charged SPIONs heavily interact with the apical cell layer, neutrally charged SPIONs showed a retarded interaction behavior. Behind the blood-placenta barrier, negatively charged SPIONs could be clearly detected. Finally, the transfer of the in vitro blood-placenta model in a microfluidic biochip allows the integration of shear stress into the system. Even without particle accumulation in a magnetic field gradient, the negatively charged SPIONs were detectable behind the barrier. In conclusion, in vitro blood-organ barrier models allow the broad investigation of magnetic hybrid materials with regard to biocompatibility, cell interaction, and transfer through cell layers on their way to biomedical application.

scholarly journals Direct mechanical stimulation of tip links in hair cells through DNA tethers

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Aakash Basu ◽  
Samuel Lagier ◽  
Maria Vologodskaia ◽  
Brian A Fabella ◽  
AJ Hudspeth
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
Mechanical Stimulation ◽  
Hair Cells ◽  
Magnetic Field Gradient ◽  
Hair Bundle ◽  
Mechanical Forces ◽  
Mechanoelectrical Transduction ◽  
Superparamagnetic Beads ◽  
Stimulation Of

Mechanoelectrical transduction by hair cells commences with hair-bundle deflection, which is postulated to tense filamentous tip links connected to transduction channels. Because direct mechanical stimulation of tip links has not been experimentally possible, this hypothesis has not been tested. We have engineered DNA tethers that link superparamagnetic beads to tip links and exert mechanical forces on the links when exposed to a magnetic-field gradient. By pulling directly on tip links of the bullfrog's sacculus we have evoked transduction currents from hair cells, confirming the hypothesis that tension in the tip links opens transduction channels. This demonstration of direct mechanical access to tip links additionally lays a foundation for experiments probing the mechanics of individual channels.

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