Polarometric Method of Plasma Diagnostics

The polarization plane rotation angle of probe signal in plasma is calculated. The estimates of the residual gas average density and the average magnitude of the magnetic field in a cesium plasma based on the effects of Faraday and Cotton-Mouton in probe laser field has been found. It is shown, that polarization plane rotation angle depends on resonance detuning of incident laser wave and transition frequency of medium atoms, magnetic field strength, and matrix element.Comment: 7 pages, 1 figur

Magnetic Field Sensing Using Whispering Gallery Modes in a Cylindrical Microresonator Infilitrated With Ferronematic Liquid Crystal

An all-fiber magnetic field sensor based on whispering-gallery modes (WGM) in a fiber micro-resonator infiltrated with ferronematic liquid crystal is proposed and experimentally demonstrated. The cylindrical microresonator is formed by a 1 cm-long section of a photonic crystal fiber infiltrated with ferronematic materials. Both ferronematics suspensions are prepared based on the nematic liquid crystal 1-(trans-4-Hexylcyclohexyl)-4-isothiocyanatobenzene (6CHBT) doped with rod-like magnetic particles in the first case and with spherical magnetic particles in the second case. WGMs are excited in the fiber microresonator by evanescent light coupling using a tapered fiber with a micron-size diameter. The Q-factor of the microresonator determined from the experimentaly measured transmission spectrum of the tapered fiber was 1.975 × 103. Under the influence of an applied magnetic field the WGM resonances experience spectral shift towards shorter wavelengths. The experimentally demonstrated sensitivity of the proposed sensor was −39.6 pm/mT and −37.3 pm/mT for samples infiltrated with rod like and spherical like ferromagnetic suspensions respectively for a magnetic field range (0-47) mT. Reducing the diameter of the cylindrical micro-resonator by tapering leads to enhancement of the magnetic field sensitivity up to −61.86 pm/mT and −49.88 pm/mT for samples infiltrated with rod like and spherical like ferromagnetic suspensions respectively for the magnetic field range (0-44.7) mT

Magnetic Nanoparticles for Application in Nanomedicine

This contribution will summarize the information about the ways of synthesizing biocompatible magnetic nanoparticles and complexes containing them and the possibility of their application in nanomedicine at magnetic drug targeting and thermal treatment of diseases by hyperthermia effect. Some procedures of the preparation of biocompatible magnetizable complexes as magnetic nanoparticles, magnetic fluids, some proteins and enzymes covalently bound to the freshly prepared magnetic nanoparticles in the presence of carbodiimide (bovine serum albumin, streptokinase, chymotrypsin, dispase, glucose oxidase), entrapment of magnetic particles into magnetoliposomes and encapsulation of clinically important drug as indomethacin and taxol together with magnetite nanoparticles in biodegradable polymer. We will summarize the results from the study of structural, magnetic and hyperthermic properties of bacterial magnetite nanoparticles i.e. magnetosomes prepared by biomineralization process of magnetotactic bacteria as a promising material for application in nanomedicine

Attenuation of the insulin amyloid aggregation in presence of Fe3O4-based magnetic fluids

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Magnetosomes - Bacterial Magnetic Nanoparticles

The magnetic properties, magneto-optical effects and hyperthermia effect were studied in solution of magnetosomes extracted from cultivated bacteria Magnetospirillum sp. AMB-1. The properties of magnetosomes were changed using different conditions during synthesis and by modification of particles after synthesis by using sonication and ultracentrifugation methods. It was shown that adding a higher amount of Wolfe's vitamin solution (WVS) or ferric quinate (FQ) cause increase of the mean diameter from 47 nm (normal condition) up to 52 nm and 58 nm respectively. Hyperthermic measurements were performed for three types of magnetosome samples: (I) M - not influenced by separation method (long - chains magnetosomes), (II) UM - after centrifugation procedure, and (III) SM - after centrifugation procedure including sonication. The Specific Absorption Rate (SAR) decreased depending on chains shortening and decrease in hysteresis too. The SAR values were 1083, 934 or 463 W/g for the sample M, UM and SM, respectively

Endovascular administration of magnetized nanocarriers targeting brain delivery after stroke

The increasing use of mechanical thrombectomy in stroke management has opened the window to local intraarterial brain delivery of therapeutic agents. In this context, the use of nanomedicine could further improve the delivery of new treatments for specific brain targeting, tracking and guidance. In this study we take advantage of this new endovascular approach to deliver biocompatible poly(D-L-lactic-co-glycolic acid) (PLGA) nanocapsules functionalized with superparamagnetic iron oxide nanoparticles and Cy7.5 for magnetic targeting, magnetic resonance and fluorescent molecular imaging. A complete biodistribution study in naïve (n = 59) and ischemic (n = 51) mice receiving intravenous or intraarterial nanocapsules, with two different magnet devices and imaged from 30 min to 48 h, showed an extraordinary advantage of the intraarterial route for brain delivery with a specific improvement in cortical targeting when using a magnetic device in both control and ischemic conditions. Safety was evaluated in ischemic mice (n = 69) showing no signs of systemic toxicity nor increasing mortality, infarct lesions or hemorrhages. In conclusion, the challenging brain delivery of therapeutic nanomaterials could be efficiently and safely overcome with a controlled endovascular administration and magnetic targeting, which could be considered in the context of endovascular interventions for the delivery of multiple treatments for stroke.We are grateful for the technical assistance received from the Pre-clinical imaging Platform at Vall d’Hebron Institut de Recerca, the Servei RMN at Universitat Autònoma de Barcelona, and the Unitat de Microscopia Òptica Avançada, Facultat de Medicina at the Universitat de Barcelona. This work has been supported under the Euronanomed MAGGBRIS collaborative project by grants from the Spanish Ministry of Science and Innovation (PCIN-2017-090 grant), the Instituto de Salud Carlos III (AC17/00004 with FEDER funds), the Slovak Research and Development Agency under the Contract No.APVV-19-0324 and the Italian Ministry of Health (Ricerca Corrente year 2017 funds); by the Expression of Interest (EoI) for Collaborative Projects on Regenerative Medicine 2019 P-CMR[C]); programs 2017-SGR-1427 and 2017-SGR-765 from the Generalitat de Catalunya; RETICS-INVICTUS PLUS from ISCIII (RD16/0019/0021 with FEDER funds); the ‘Severo Ochoa’ Program for Centers of Excellence in R&D (SEV-2015-0496) and the RYC-2017- 22412 and PID2019-107989RB-I00. A.G has been supported by fellowships from ISCIII (FI17/00073 and MV18/00006), A.R by a visiting-scientist fellowship from ISCIII (BA17/00052) and Y. Z has been supported by the China Scholarship Council (CSC).Peer reviewe

Temperature Effect on Anisotropy of Acoustic Attenuation in Magnetic Fluids Based on Transformer Oil

Magnetic nanoparticles in magnetic fluids under the effect of magnetic field create structures, which are not arranged uniformly. These structures have various shapes dependent on the intensity and duration of applied magnetic field. In the case of such structures the anisotropy of acoustic attenuation can be observed. The effect of temperature on this process was studied by acoustic spectroscopy in transformer oil-based magnetic fluids. Taketomi theory that assumes existence of spherical clusters was used. These clusters form long chains, aligned in magnetic field direction. The cluster radius, the number density of the colloidal nanoparticles as well as other parameters of magnetic nanoparticles were determined from experimental results. These data allowed to draw conclusions about the changes in the parameters describing the structures of magnetic nanoparticles in the investigated magnetic fluid caused by different temperatures