Search results for "RESONANCE"
showing 10 items of 6625 documents
The Interaction Mechanism of Intrinsically Disordered PP2A Inhibitor Proteins ARPP-16 and ARPP-19 With PP2A
2021
Protein phosphatase 2A (PP2A) activity is critical for maintaining normal physiological cellular functions. PP2A is inhibited by endogenous inhibitor proteins in several pathological conditions including cancer. A PP2A inhibitor protein, ARPP-19, has recently been connected to several human cancer types. Accordingly, the knowledge about ARPP-19—PP2A inhibition mechanism is crucial for the understanding the disease development and the therapeutic targeting of ARPP-19—PP2A. Here, we show the first structural characterization of ARPP-19, and its splice variant ARPP-16 using NMR spectroscopy, and SAXS. The results reveal that both ARPP proteins are intrinsically disordered but contain transient…
Magnetization Dynamics in Proximity-Coupled Superconductor-Ferromagnet-Superconductor Multilayers
2020
In this work, magnetization dynamics is studied in superconductor/ferromagnet/superconductor three-layered films in a wide frequency, field, and temperature ranges using the broad-band ferromagnetic resonance measurement technique. It is shown that in presence of both superconducting layers and of superconducting proximity at both superconductor/ferromagnet interfaces a massive shift of the ferromagnetic resonance to higher frequencies emerges. The phenomenon is robust and essentially long-range: it has been observed for a set of samples with the thickness of ferromagnetic layer in the range from tens up to hundreds of nanometers. The resonance frequency shift is characterized by proximity-…
Experimental evidence on microwave induced electron losses from ECRIS plasma
2018
The balance between warm and hot (>1 keV) electron density and their losses from the magnetic confinement system of an Electron Cyclotron Resonance Ion Source (ECRIS) plasma is considered to be one of the main factors determining the rate of the high charge state ion production. One of the key loss channels for heated electrons is thought to be induced by the injected microwaves. While this loss mechanism, referred to as rf-induced pitch angle scattering, has been studied theoretically and with computational tools, direct experimental evidence of its significance in minimum-B ECRIS plasmas remains limited. In this work, experimental evidence of microwave induced electron losses in the axial…
Influence of axial mirror ratios on the kinetic instability threshold in electron cyclotron resonance ion source plasma
2022
International audience; Electron Cyclotron Resonance (ECR) ion source plasmas are prone to kinetic instabilities. The onset of the instabilities manifests as emission of microwaves, bursts of electrons expelled from the plasma volume, and the collapse of the extracted highly charged ion (HCI) currents. Consequently, the instabilities limit the HCI performance of ECR ion sources by limiting the parameter space available for ion source optimization. Previous studies have shown that the transition from stable to unstable plasma regime is strongly influenced by the magnetic field structure, especially the minimum field value inside the magnetic trap (Bmin). This work focuses to study the role o…
Folate targeted coated SPIONs as efficient tool for MRI
2017
The development of more sensitive diagnostic tools allowing an early-stage and highly efficient medical imaging of tumors remains a challenge. Magnetic nanoparticles seem to be the contrast agents with the highest potential, if properly constructed. Therefore, in this study, hybrid magnetic nanoarchitectures were developed using a new amphiphilic inulin-based graft copolymer (INU-LAPEG-FA) as coating material for 10-nm spinel iron oxide (magnetite, Fe3O4) superparamagnetic nanoparticles (SPION). Folic acid (FA) covalently linked to the coating copolymer in order to be exposed onto the nanoparticle surface was chosen as the targeting agent because folate receptors are upregulated in many can…
Conventional MRI-Derived Biomarkers of Adult-Type Diffuse Glioma Molecular Subtypes: A Comprehensive Review.
2022
The introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Although many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences remain the reference point in the study and characterization of brain tumors. A summary of the conventional imaging features of glioma molecular subtypes should be useful as a tool for daily diagnostic brain tumor management. Hence, t…
High content and dispersion of Gd in bimodal porous silica: T2 contrast agents under ultra-high magnetic fields
2022
Silica-based UVM-7-type bimodal mesoporous materials with high gadolinium content (∞ ≥ Si/Gd ≥ 13) have been synthesized through a one-pot surfactant-assisted procedure from hydroalcoholic solution using a cationic surfactant as template, and starting from atrane complexes of Gd and Si as inorganic precursors. The novel synthetic pathway developed in the study preserves the UVM-7-type architecture while optimizing the dispersion of the Gd-guest species at the nanoscale and even at atomic level. It has been determined that the number of Gd atoms forming clusters is always less than 10. The behaviour under exposure to ultra-high magnetic fields reveals a significant increase in the transversa…
Magnetic Resonance Venography of chronic cerebrospinal venous insufficiency in patients with associated multiple sclerosis
2011
Background: Multiple sclerosis (MS) is a chronic disease with not well understood etiology. Recently, a possible association of MS with compromised venous outflow from the brain and spinal cord has been studied (chronic cerebrospinal venous insufficiency – CCSVI). Angioplasties of internal jugular veins (IJV) and azygous vein (AV) have given promising results, with improvements in patients’ clinical status. Material/Methods: 830 patients with clinically defined MS were scanned from the level of sigmoid sinuses to the junction with brachiocephalic veins, as well as at the level of AV. T2-weighted, 2D TOF and FIESTA sequences were used. Results: The examination revealed a slower blood flow in…
Bilateral activations in operculo‐insular area show temporal dissociation after peripheral electrical stimulation in healthy adults
2018
Interhemispheric transfer is necessary for sensory integration and coordination of body sides. We studied how somatosensory input from one body side may reach both body sides. First, we investigated with 17 healthy adults in which uni‐ and bilateral brain areas were involved in consecutive stages of automatic sensory processing of non‐nociceptive peripheral stimulation. Somatosensory evoked fields (SEFs) to electrical stimulation were recorded with 306‐channel magnetoencephalography in two conditions. First, SEFs were registered following sensory radial nerve (RN) stimulation to dorsal surface of the right hand and second, following median nerve (MN) stimulation at the right wrist. Cortical…
Identification of proprioceptive thalamocortical tracts in children: comparison of fMRI, MEG, and manual seeding of probabilistic tractography
2022
Publisher Copyright: © The Author(s) 2022. Published by Oxford University Press. Studying white matter connections with tractography is a promising approach to understand the development of different brain processes, such as proprioception. An emerging method is to use functional brain imaging to select the cortical seed points for tractography, which is considered to improve the functional relevance and validity of the studied connections. However, it is unknown whether different functional seeding methods affect the spatial and microstructural properties of the given white matter connection. Here, we compared functional magnetic resonance imaging, magnetoencephalography, and manual seedin…