Search results for "Paramagnetic"
showing 10 items of 600 documents
Effect of irradiation temperature on the radiation induced attenuation of Ge-doped fibers
2016
International audience; The UV-visible radiation induced attenuation (RIA) was studied in Ge-doped optical fibers, during X-ray (10 keV) irradiations at different temperatures. By comparing the spectra recorded in dissimilarly irradiated samples we evidenced the impact of the irradiation temperature. In details, we highlighted that, from a certain dose, increasing the temperature the RIA decreases for wavelengths lower than 470 nm, whereas at higher wavelengths the RIA depends only on the dose. Such findings suggest that it is possible to distinguish the irradiation temperature by comparing the signal at two different wavelengths. From the microscopic point of view, it appears that the RIA …
Out-of-phase second harmonic detection as a tool for the determination of relaxation times
2014
Oxidation Processes in Sicilian Olive Oils Investigated by a Combination of Optical and EPR Spectroscopy
2012
: Extra virgin olive oil (EVOO) is recognized as one of the healthiest foods for its high content of antioxidants, which forestall and slow down radical formation. Free radical-initiated oxidation is considered one of the main causes of rancidity in fats and oils. As a consequence, reliable protocols for the investigation of oil oxidation based on selective, noninvasive, and fast methods are highly desirable. Here we report an experimental approach based on UV-Vis absorbance, steady-state fluorescence, and electron paramagnetic resonance (EPR) spectroscopy for studying oxidation processes induced by temperature for a period up to 35 d on Sicilian EVOO samples. We followed the decrease in β…
Spectroscopic studies of water-soluble superstructured iron(III) porphyrin. Interaction with the bovine serum albumin protein
2018
Acid-base equilibrium of the “one-face”-hindered sulfonated porphyrin, α5,15-[2,2′(dodecamethyleneoxy),(5-sulfonato)diphenyl]-10,20-bis(2-hydroxy,5-sulfonatophenyl)porphyrinato iron(III), has been ...
Purification by affinity chromatography of H1 RNA-Binding Proteins from rat brain
2003
Post-transcriptional regulation of mRNA metabolism is involved in processes as different as cell fate specification in development and cell response to a large variety of environmental cues. Regulation of all steps of RNA metabolism depends on RNA-binding proteins (RBPs). By using a T1 RNase protection assay, we previously identified three H1° RNA-binding factors (p40, p70 and p110), highly expressed in the rat brain. Here we report enrichment of these factors from brain extracts, obtained by affinity chromatography of biotinylated H1° RNA-protein complexes on streptavidin-conjugated paramagnetic particles. The purified proteins maintain RNA-binding ability and preference for histone messag…
An interpretation of EPR spectra of azide ligated superoxide dismutase from Propionibacterium shermanii
1995
A self-consistent description of the EPR spectra of the azide ligated SOD is obtained by taking into account the general configuration of the crystal field splitting in the crystal field Hamiltonian. The spread in the rhombicity parameter due to the presence of different conformational substates is introduced.
Corrigendum to “A diferric complex from metal-assisted methanolysis of di-2,6-(2-pyridylcarbonyl)-pyridine: Structural, magnetic and spectroscopic (M…
2010
Corrigendum to ‘‘A diferric complex from metal-assisted methanolysis of di-2,6-(2-pyridylcarbonyl)-pyridine: Structural, magnetic and spectroscopic (Mossbauer, EPR) study” [Polyhedron 28 (2009) 15] Anastasia N. Georgopoulou , Rosa Adam, Yiannis Sanakis , Catherine P. Raptopoulou , Vassilis Psycharis , Rafael Ballesteros , Belen Abarca , Athanassios K. Boudalis a,* a Institute of Materials Science, NCSR ‘‘Demokritos”, 153 10 Aghia Paraskevi Attikis, Greece Departamento de Quimica Organica, Faculdad de Farmacia, Universidad de Valencia, Avda. Vicente Andres Estelles s/n, 46100 Burjassot (Valencia), Spain
The active center of superoxide dismutase from Propionibacterium shermanii
1996
A self-consistent description of the EPR spectra and of the Mossbauer spectra of the natural superoxide dismutase from Propionibacterium shermanii with ferric iron as an active centre is presented. The spectra were measured at pH 6.5, 7.8 and 9.4. The theoretical approach is based on the use of the complete crystal field Hamiltonian for the high-spin ferric complexes with due regard for the terms of the fourth power of the electronic spin. It is shown that a SOD molecule can exist in two conformations. The low-pH conformation has predominantly trigonal symmetry, while the high-pH conformation has the symmetry close to the «extreme rhombic». This interpretation is in full agreement with EXAF…
Use of Super Paramagnetic Iron Oxide Nanoparticles as Drug Carriers in Brain and Ear: State of the Art and Challenges
2021
International audience; Drug delivery and distribution in the central nervous system (CNS) and the inner ear represent a challenge for the medical and scientific world, especially because of the blood–brain and the blood–perilymph barriers. Solutions are being studied to circumvent or to facilitate drug diffusion across these structures. Using superparamagnetic iron oxide nanoparticles (SPIONs), which can be coated to change their properties and ensure biocompatibility, represents a promising tool as a drug carrier. They can act as nanocarriers and can be driven with precision by magnetic forces. The aim of this study was to systematically review the use of SPIONs in the CNS and the inner e…
Studies on coordination compounds—VIII. Syntheses, structural, magnetic, spectral and thermal properties of some cobalt(II), nickel(II) and copper(II…
1995
Abstract The complexes bis[triaqua(2-aminopyrimidine)-μ-sulphato-O,O′-cobalt(II)] dihydrate (1), catena-[diaqua(2(2-aminopyrimidine))-μ-sulphato-O,O′nickel(II)]2-amino-pyrimidine (2), [pentaaqua(2-aminopyrimidine)nickel(II)]sulphate 2-aminopyrimidine (3) and catena-[aqua(2(2-aminopyrimidine))-μ-sulphato-O,O′-copper(II)] dihydrate (4) were prepared, structure determined by X-ray methods and physical properties studied by magnetic, IR, NMR, EPR and reflectance methods. The thermal behaviour was studied by TG and mass spectrometric methods. The results are discussed on a structural basis.