Recent evidence suggests that bats can detect the geomagnetic field, but the way in which this is used by them for navigation to a home roost remains unresolved. The geomagnetic field may be used by animals both to indicate direction and to locate position. In birds, directional information appears to ...

The rheology of granular materials near an interface is investigated through proton magnetic resonance imaging. A new cylinder shear apparatus has been inserted in the magnetic resonance imaging device, which allows the control of the radial confining pressure exerted by the outer wall on the grains and the measurement of ...

One of the main vital signs used in patient monitoring during Magnetic Resonance Imaging (MRI) is Electro-Cardio-Gram (ECG). Unfortunately, magnetic fields gradients induce artefacts which severely affect ECG quality. Adaptive Noise Cancelling (ANC) is one of the preferred techniques for artefact removal. ANC involves the adaptive estimation of the impulse ...

An application of magnetic Compton scattering as a new tool to measure a spin-specific magnetic hysteresis (SSMH) loop is introduced and its validity demonstrated. The applied magnetic field dependence of the integrated intensity of magnetic Compton scattering spectra, which reflect only the spin-dependent magnetic properties of magnetically active electrons, was ...

The self-assembly of nanoparticles into higher organizations in a controlled manner has critical importance for the utility of the unique properties of nanoparticles. The behavior of magnetic Fe(3)O(4) nanoparticles (MNPs) with an average size of 6 nm under an enhanced magnetic force is reported. Upon evaporation of the solvent where ...

The magnetic properties of ultra-small (3 nm) CoFe(2)O(4) nanoparticles have been investigated by DC magnetization measurements as a function of temperature and magnetic field. The main features of the magnetic behaviour are blocking of non-interacting particle moments (zero-field-cooled magnetization T(max) approximately 40 K), a rapid increase of saturation magnetization (up ...

Recent advances in high-field (>or=7 T) MRI have made it possible to study the fine structure of the human brain at the level of fiber bundles and cortical layers. In particular, techniques aimed at detecting MRI resonance frequency shifts originating from local variation in magnetic susceptibility and other sources have ...

The resistive decay of chains of three interlocked magnetic flux rings is considered. Depending on the relative orientation of the magnetic field in the three rings, the late-time decay can be either fast or slow. Thus, the qualitative degree of tangledness is less important than the actual value of the ...

Molecular imaging based on MRI is currently hampered by the lack of genetic reporters for in vivo imaging. We determined that the commercially available substrate S-Gal can be used to detect genetically engineered beta-galactosidase expressing cells by MRI. The effect and specificity of the reaction between beta-galactosidase and S-Gal on ...

In the presence of alternating-sinusoidal or rotating magnetic fields, magnetic nanoparticles will act to realign their magnetic moment with the applied magnetic field. The realignment is characterized by the nanoparticle's time constant, tau. As the magnetic field frequency is increased, the nanoparticle's magnetic moment lags the applied magnetic field at ...

Magnetisation transfer contrast (MTC) is an important MR contrast generating mechanism to characterise the undetectable bound protons indirectly using the decreased signal intensity of the observable free protons. MTC imaging typically employs a range of off-resonance RF pre-saturation pulse with maintaining the RF magnetic field (B(1)) at a specified value. ...

A former radioactive waste disposal site is surveyed with two non-intrusive geophysical techniques, including magnetic gradiometry and electromagnetic induction. Data were gathered over the site by towing the geophysical equipment mounted to a non-electrically conductive and non-magnetic fibre-glass cart. Magnetic gradiometry, which detects the location of ferromagnetic material, including iron ...

The past year has witnessed ongoing progress in the field of molecular MRI of the myocardium. In addition, several novel fluorescent agents have been introduced and used to image remodeling in the injured myocardium. New techniques to image myocardial microstructure, such as diffusion spectrum MRI, have also been introduced and ...

INTRODUCTION: Ex-PRESS mini glaucoma shunt is a miniature, stainless steel, nonvalved device used for the treatment of glaucoma. The purpose of this study was to evaluate the safety of the Ex-PRESS glaucoma shunt during magnetic resonance (MR) imaging. METHODS: The effect of a magnetic field on the Ex-PRESS glaucoma shunt ...

We showed that a Ag-SiO(2)-Ag Fabry-P?rot cavity can be used in near-field imaging based on omnidirectional resonance tunneling. The omnidirectional resonance was experimentally demonstrated in the Ag-SiO(2)-Ag resonant cavity working at a wavelength of 365 nm. The resonant cavity lens with high transmittance and high image fidelity was fabricated using ...

OBJECTIVE: This work investigates the influence of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEG-fMRI recordings. The quality of the ERPs after BallistoCardioGraphic (BCG) artifact removal, as well as the reproducibility of the waveforms in different environments is investigated. METHODS: We consider a Detection, a ...

Currently several groups are actively researching the integration of a megavoltage teletherapy unit with magnetic resonance (MR) imaging for real-time image-guided radiotherapy. The use of a multileaf collimator (MLC) for intensity-modulated radiotherapy for linac-MR units must be investigated. The MLC itself will likely reside in the fringe field of the ...

STUDY DESIGN: Technical report. OBJECTIVE: To minimize the gross artefact associated with a conventional metallic lumbar total disc arthroplasty (TDA) device on a conventional high field-strength (1.5 Tesla [T]) magnetic resonance imaging (MRI) scanner. SUMMARY OF BACKGROUND DATA: Gross artefact is often apparent with ferromagnetic metallic TDA devices on conventional ...

For the applications of localized hyperthermia, an improved magnetic induction-heating system is described. The associated components of this system, for example, coils for generating magnetic field, magnetic circuit for flux path, and ferrite needles for generating heat by magnetic induction, all have been explained. An animal experiment of induction-heating hyperthermia ...

The gradient fields in magnetic resonance imaging (MRI) will in some circumstances exceed the ICNIRP guidelines of occupational electromagnetic field exposure when personnel are near the scanner during MRI scanning. In this work we have shown that using commercially available modified sequences for noise reduction purposes, exposure will decrease by ...

With a bottom-up assemble technology, heterogeneous magnetic nanobrushes, consisting of Co nanowire arrays and ferromagnetic Fe70Co30 nanofilm, have been fabricated using an anodic aluminum oxide template method combining with sputtering technology. Magnetic measurement suggests that the magnetic anisotropy of nanobrush depends on the thickness of Fe70Co30 layer, and its total ...

The use of the minimum stored energy current density map-based methodology of designing closed-bore symmetric superconducting magnets was described recently. The technique is further developed to cater for the design of interventional-type MRI systems, and in particular open symmetric magnets of the double-doughnut configuration. This extends the work to multiple ...

This paper describes the synthesis of thermoresponsive hydrogel bead for the implementation of untethered medical microrobots and other microdevices. These entities will have magnetic nanoparticles embedded, and will be targeted inside the body with an adapted Magnetic Resonance Imaging (MRI) system, and then triggered by the application of an alternating ...

The prefrontal cortex is a common target brain structure in psychiatry and neuroscience due to its role in working memory and cognitive control. Large differences in magnetic susceptibility between the air-filled sinuses and the tissue/bone in the frontal part of the human head cause a strong and highly localized magnetic ...

Distal forelimb specimens of eight skeletally mature horses were imaged using proton density turbo spin echo, T1-weighted spoiled gradient echo, T2*-weighted gradient echo, short tau inversion recovery and T2-weighted fast spin echo sequences with the limb parallel to the main magnetic field, and with angulation of the limb relative to ...

The finite difference time domain (FDTD) method is a popular technique for computational electromagnetics (CEM). The large computational power often required, however, has been a limiting factor for its applications. In this paper, we will present a graphics processing unit (GPU)-based parallel FDTD solver and its successful application to the ...

Catheter navigation and placement through the arterial network is a major limitation for clinical procedure. In this article, a specific catheter tip and a modified clinical MRI scanner with an upgraded gradient system are used to steer a catheter through a single Y-shaped bifurcation. Safety aspects are analyzed to avoid ...

Here we demonstrate the mechanical robustness of microfabricated torsional magnetic actuators in withstanding the magnetic fields produced by a 7 T MRI magnet. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both uniform and non-uniform magnetic fields. The results show no ...

Nanomagnetic particles have been already taken into account as drug carriers thank to the possibility to control their movement to a specific location where the treatment is required by means of high gradient magnetic fields (HGMF). In this work the layer-by-layer technique (LbL) and nanomagnetic particles were used to developed ...

Vestibular schwannomas (VS) account for approximately 8% of all intracranial neoplasms and nearly 80% of all cerebellopontine angle tumors. Spontaneous intratumoral hemorrhage (ITH) remains a rare entity with only 10 published reports existing in the international literature. In the present case, we discuss the clinical presentation, radiographic evaluation and management ...

Magnetic field inhomogeneity is a long-standing problem in magnetic resonance imaging (MRI) and spectroscopic imaging (MRSI). Specifically, in MRSI, field inhomogeneity, if not corrected, can cause frequency shifts, line broadening, and lineshape distortions in the spectral peaks. This paper addresses the problem of correcting the field inhomogeneity effects on limited ...

The main goal of glioma surgery is to maximize tumor resection while minimizing neurologic injury. The use of high-field intraoperative magnetic resonance imaging (iMRI) and intraoperative cortical mapping (IOM) together enable the surgeon to increase the extent of tumor resection (EOR) and preserve the neurological function. However, there is insufficient ...

BACKGROUND: Malaria parasites generate free haem upon catabolism of host haemoglobin during their intraerythrocytic growth cycle. In order to minimize oxidative toxicity of the ferric iron, the free haem molecules are polymerized into the biomineral beta-haematin (commonly referred to as haemozoin). Haemozoin crystals are paramagnetic, and this property can be ...

BACKGROUND: For clinical applications of mesenchymal stem cells (MSCs), labeling and tracking is crucial to evaluate cell distribution and homing. Magnetic resonance imaging (MRI) has been successfully established detecting MSCs labeled with superparamagnetic particles of iron oxide (SPIO). Despite initial reports that labeling of MSCs with SPIO is safe without ...

There are advantages to conducting cardiovascular magnetic resonance (CMR) studies at a field strength of 3.0 Telsa, including the increase in bulk magnetization, the increase in frequency separation of off-resonance spins, and the increase in T1 of many tissues. However, there are significant challenges to routinely performing CMR at 3.0 ...

PURPOSE: Stroke and subclinical "silent infarcts" are major causes of morbidity in children with Sickle Cell Disease (SCD). Ischemic strokes are more common in younger children while hemorrhagic strokes are more frequent in adults. The goal of neuroimaging in acute stroke is to document whether the stroke is ischemic or ...

In this work some possible applications of negative permeability magnetic metamaterial lenses for magnetic resonance imaging (MRI) are analyzed. It is shown that using magnetic metamaterials lenses it is possible to manipulate the spatial distribution of the radio-frequency (RF) field used in MR systems and, under some circumstances, improve the ...

RATIONALE AND OBJECTIVES: The increasing spread of high-field and ultra-high-field magnetic resonance imaging (MRI) scanners has encouraged new discussion of the safety aspects of MRI. Few studies have been published on possible cognitive effects of MRI examinations. The aim of this study was to examine whether changes are measurable after ...

PURPOSE: Considering the rapidly increasing number of clinical high-field MR imagers and the lack of data regarding interference with magnetically adjustable cerebrospinal fluid (CSF) shunt valves, valve safety was assessed with regard to magnetic field interactions: imaging artifacts, heating, magnetic forces, and functional changes in a phantom study at 3.0 ...

The effects of extremely low frequency (ELF) magnetic fields on membrane F(0)F(1)-ATPase activity have been studied. When the F(0)F(1)-ATPase was exposed to 60 Hz magnetic fields of different magnetic intensities, 0.3 and 0.5 mT magnetic fields enhanced the hydrolysis activity, whereas 0.1 mT exposure caused no significant changes. Even if ...

BACKGROUND: Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Magnetic nanoparticles for cancer therapy and diagnosis have been developed on the basis of their unique physico-chemical properties not present in other materials. Their versatility is widely exploited in such diverse techniques as cell and macromolecule ...

This article reports the purification and separation of magnetic nanoparticle mixtures using differential magnetic catch and release (DMCR). This method applies a variable magnetic flux orthogonal to the flow direction in an open tubular capillary to trap and controllably release magnetic nanoparticles. Magnetic moments of 8, 12, and 17 nm ...

Magnetically separable photocatalyst beads containing nano-sized iron oxide in alginate polymer were prepared. This magnetic photocatalyst beads are used in slurry-type reactors. The magnetism of the catalyst arises from the nanostructured particles gamma-Fe(2)O(3), by which the catalyst can be easily recovered by the application of an external magnetic field. These ...

The absence of centrosymmetry in the enantiopure chiral magnet [N(CH(3))(n-C(3)H(7))(2)(C*H(CH(3))C(2)H(5))][Mn(II)Cr(III)(ox)(3)] allows the observation of bulk second harmonic generation (SHG) in this material. At low temperature, the onset of magnetization gives birth to a magnetization-induced SHG (MSHG) contribution. With an angular shift of 13.1 degrees upon magnetization reversal, the MSHG effects ...

We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts ...

In magnetic resonance imaging (MRI), there have been three basic techniques to encode the spatial origin of the signals, i.e. Fourier and radio frequency encoding and the use of sensitivity information of sensor arrays. In this paper, we introduce a new encoding method, which we call polarization encoding. The method ...

It is well known that adding salt to a colloidal solution stabilized by electrostatic repulsions can induce its destabilization. When this colloidal solution is encapsulated inside liposomes an in situ precipitation can be induced by slightly modification of the environment: application of a magnetic field in the case of magnetic ...

Human exposure to magnetic fields, increased through use of new technologies like magnetic resonance imaging (MRI), has prompted investigations into possible effects of static magnetic fields (SMFs) on cellular processes. However, controversy still remains between many studies, which likely results from a lack of uniformity across experimental parameters, including the ...

PURPOSE: To investigate whether scanning at different field strengths and pulse sequences would influence reproducibility of corpus callosum (CC) morphometric measurements as variations in scanning parameters may result in differences in contrast properties between resulting images that are independent of the underlying tissue but rather reflect the physics of the ...

While low-field magnetic resonance (MR) images can provide useful information in the investigation of proximal metacarpal region pain, an in-depth knowledge of anatomy and comparison with more detailed high-field images are essential to understand the meaning of different signal intensities within tissues. This anatomic description is based on low-field and ...