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Magnetic field

Abaynesh Yihdego Gebreyohannes, Rosalinda Mazzei, Mohamed Yahia Marei Abdelrahim, Giuseppe Vitola, Elena Porzio, Giuseppe Manco, Mihail Barboiu, Lidietta Giorno
The need to find alternative bioremediation solutions for organophosphate degradation pushed the research to develop technologies based on organophosphate degrading enzymes, such as phosphotriesterase. The use of free phosphotriesterase poses limits in terms of enzyme reuse, stability and process development. The heterogenization of enzyme on a support and their use in bioreactors implemented by membrane seems a suitable strategy, thanks to the ability of membranes to compartmentalize, to govern mass transfer and provide microenvironment with tuned physico-chemical and structural properties...
May 24, 2018: Bioconjugate Chemistry
Shao-Li Hong, Ya-Nan Zhang, Ya-Hua Liu, Man Tang, Dai-Wen Pang, Gary Wong, Jianjun Chen, Xiangguo Qiu, George F Gao, Wenjun Liu, Yuhai Bi, Zhi-Ling Zhang
Ebola virus (EBOV) disease is a complex zoonosis that is highly virulent in humans, and has caused many deaths. Highly sensitive detection of EBOV is of great importance to early-stage diagnosis for increasing the probability of survival. Herein, we established a cellular beacon-mediated counting strategy for ultrasensitive EBOV assay on a micromagnetic platform. The detection platform that was assisted by on-demand magnetic field manipulation showed high integration, and enhanced complex sample pretreatment ability by magnetophoretic separation and continuous flow washing...
May 24, 2018: Analytical Chemistry
Alessandro Surrente, Łukasz Klopotowski, Nan Zhang, Michal Baranowski, Anatolie Mitioglu, Mariana V Ballottin, Peter C M Christianen, Dumitru Dumcenco, Yen-Cheng Kung, Duncan K Maude, Andras Kis, Paulina Plochocka
Degenerate extrema in the energy dispersion of charge carriers in solids, also referred to as valleys, can be regarded as a binary quantum degree of freedom, which can potentially be used to implement valleytronic concepts in van der Waals heterostructures based on transition metal dichalcogenides. Using magneto-photoluminescence spectroscopy, we achieve a deeper insight into the valley polarization and depolarization mechanisms of interlayer excitons formed across a MoS2 /MoSe2 /MoS2 heterostructure. We account for the non-trivial behavior of the valley polarization as a function of the magnetic field by considering the interplay between exchange interaction and phonon mediated intervalley scattering in a system consisting of Zeeman-split energy levels...
May 23, 2018: Nano Letters
Casey Van Stappen, Dimitrios Maganas, Serena DeBeer, Eckhard Bill, Frank Neese
Herein, we utilize a variety of physical methods including magnetometry (SQUID), electron paramagnetic resonance (EPR), and magnetic circular dichroism (MCD), in conjunction with high-level ab initio theory to probe both the ground and ligand-field excited electronic states of a series of V(IV) ( S = 1 /2 ) and V(III) ( S = 1) molecular complexes. The ligand fields of the central metal ions are analyzed with the aid of ab initio ligand-field theory (AILFT), which allows for a chemically meaningful interpretation of multireference electronic structure calculations at the level of the complete-active-space self-consistent field with second-order N-electron valence perturbation theory...
May 23, 2018: Inorganic Chemistry
Theodore J Zwang, Edmund C M Tse, Jacqueline K Barton
DNA charge transport chemistry involves the migration of charge over long molecular distances through the aromatic base pair stack within the DNA helix. This migration depends upon the intimate coupling of bases stacked one with another, and hence any perturbation in that stacking, through base modifications or protein binding, can be sensed electrically. In this review we describe the many ways DNA charge transport chemistry has been utilized to sense changes in DNA including the presence of lesions, mismatches, DNA-binding proteins, protein activity, and even reactions under weak magnetic fields...
May 23, 2018: ACS Chemical Biology
Segun Goh, Andreas M Menzel, Hartmut Löwen
Ferrogels are smart soft materials, consisting of a polymeric network and embedded magnetic particles. Novel phenomena, such as the variation of the overall mechanical properties by external magnetic fields, emerge consequently. However, the dynamic behavior of ferrogels remains largely unveiled. In this paper, we consider a one-dimensional chain consisting of magnetic dipoles and elastic springs between them as a simple model for ferrogels. The model is evaluated by corresponding simulations. To probe the dynamics theoretically, we investigate a continuum limit of the energy governing the system and the corresponding equation of motion...
May 23, 2018: Physical Chemistry Chemical Physics: PCCP
Alexandre Rainha Campos, Luisa Biscoito, Maria Gabriela Gasparinho
Intraventricular gangliogliomas presenting with spontaneous hemorrhage are rare. Due to high density of important tracts lateral to the ventricular atrium, the intraparietal trans sulcal approach is a good option to remove lesions in this location. These tracts are displaced and sometimes destroyed by the presence of large masses. A 33-year-old male presented with a sudden headache and a generalized seizure. He had a left visual field hemianopia and left visual field neglect. Brain computer tomography and magnetic resonance imaging revealed a hemorrhagic tumor located in his right atrium...
March 29, 2018: Acta Médica Portuguesa
Bin Zhao, Huan-Cheng Hu
A new concept for constructing metal-organic frameworks (MOFs) based on multicentre-bonded [MI]8 (M = Mn, Zn) clusters with cubic aromaticity is discussed. In principle, intermolecular/intramolecular hydrogen-bonding, π***π stacking, coordinated covalent bonding and ionic bonding usually account for the structures of MOFs, and multicentered bonds generally exist in cation, anion, neutral and zwitterionic radicals, while rarely appear in MOFs. Meanwhile, aromaticity became one of the most vexing yet fascinating key concepts in chemistry since the proposition of the structure of benzene molecule in 1865...
May 23, 2018: Chemistry: a European Journal
Bingshan Tao, Philippe Barate, Xavier Devaux, Pierre Renucci, Julien Frougier, Abdelhak Djeffal, Shiheng Liang, Bo Xu, Michel Hehn, Henri Jaffrès, Jean-Marie George, Xavier Marie, Stéphane Mangin, Xiufeng Han, Zhanguo Wang, Yuan Lu
Remanent spin injection into a spin light emitting diode (spin-LED) at zero magnetic field is a prerequisite for future application of spin optoelectronics. Here, we demonstrate the remanent spin injection into GaAs based LEDs with a thermally stable Mo/CoFeB/MgO spin injector. A systematic study of magnetic properties, polarization-resolved electroluminescence (EL) and atomic-scale interfacial structures has been performed in comparison with the Ta/CoFeB/MgO spin injector. The perpendicular magnetic anisotropy (PMA) of the Mo/CoFeB/MgO injector shows more advanced thermal stability than that of the Ta/CoFeB/MgO injector and robust PMA can be maintained up to 400 °C annealing...
May 23, 2018: Nanoscale
Marek Glinka, Stanisław Gawron, Aleksander Sieroń, Katarzyna Pawłowska-Góral, Grzegorz Cieślar, Karolina Sieroń
Results of research assessing the biological impact of static magnetic fields are controversial. So far, they have not provided a clear answer to their influence on cell functioning. Since the use of permanent magnets both in everyday life and in industry becomes more and more widespread, the investigations are continued in order to explain these controversies and to evaluate positive applications. The goal of current work was to assess the impact of static magnetic field of different intensities on redox homeostasis in cultures of fibroblasts...
2018: BioMed Research International
Victor Rusakov, Yuriy Raikher
With allowance for orientational Brownian motion, the magnetorelaxometry (MRX) signal, i.e., the decay of magnetization generated by an ensemble of ferromagnet nanoparticles, each of which bears a macromolecular corona (a loose layer of polymer gel) is studied. The rheology of corona is modelled by the Jeffreys scheme. The latter, although comprising only three phenomenological parameters, enables one to describe a wide spectrum of viscoelastic media: from linearly viscous liquids to weakly-fluent gels. The "transverse" configuration of MRX is considered where the system is subjected to a DC (constant bias) field, whereas the probing field is applied perpendicularly to the bias one...
May 22, 2018: Sensors
Wenguang Feng, Shibin Liu
Nonlinearity is a prominent limitation to the calibration performance for two-axis fluxgate sensors. In this paper, a novel nonlinear calibration algorithm taking into account the nonlinearity of errors is proposed. In order to establish the nonlinear calibration model, the combined effort of all time-invariant errors is analyzed in detail, and then harmonic decomposition method is utilized to estimate the compensation coefficients. Meanwhile, the proposed nonlinear calibration algorithm is validated and compared with a classical calibration algorithm by experiments...
May 22, 2018: Sensors
Jingyu Jia, Qiangqiang Wei, Tianlong Wu, Dingwen He, Xigao Cheng
BACKGROUND: Since disc sequestration that mimics a tumor is rare and sometimes presents with an atypical appearance upon magnetic resonance imaging (MRI), it is often confused with other more common epidural and intradural neoplasms, particularly neurinoma. Open surgery is necessary due to the difficult of achieving a definitive diagnosis using computed tomography, MRI, and gadolinium- enhanced MRI prior to operation. Herein, we describe the use of coronal MR images of 3D fast-field echo with water selective excitation in the diagnosis of disc sequestration mimicking a tumor...
May 22, 2018: BMC Musculoskeletal Disorders
Yue Zhu, Yuheng Gao, Shane Rodocker, Igor Savukov, Christian Hilty
We describe the multi-nuclear detection of nuclear spin optical rotation (NSOR), an effect dependent on the hyperfine interaction between nuclear spins and electrons. Signals of 1 H and 19 F are discriminated by frequency in a single spectrum acquired at sub-mili Tesla field. The simultaneously acquired optical signal along with the nuclear magnetic resonance (NMR) signal allows the calculation of the relative magnitude of the NSOR constants corresponding to different nuclei within the sample molecules. This is illustrated by a larger NSOR signal measured at the 19 F frequency despite a smaller corresponding spin concentration...
May 22, 2018: Journal of Physical Chemistry Letters
Vincent Groenhuis, Françoise J Siepel, Jeroen Veltman, Jordy K van Zandwijk, Stefano Stramigioli
Suspicious lesions in the breast that are only visible on magnetic resonance imaging (MRI) need to be biopsied under MR guidance with high accuracy and efficiency for accurate diagnosis. The aim of this study is to present a novel robotic system, the Stormram 4, and to perform preclinical tests in an MRI environment. Excluding racks and needle, its dimensions are 72 × 51 × 40 mm. The Stormram 4 is driven by two linear and two curved pneumatic stepper motors. The linear motor is capable of exerting 63 N of force at a pressure of 0...
May 21, 2018: Annals of Biomedical Engineering
E F Levitsky, B I Laptev, G N Sidorenko, T G Ivanova, N P Gorlenko, L V Antoshkin
The application of the dielectrometric technology in the combination with the resonance method and thermometry has been shown to provide an insight into a variety of factors including the influence of the magnetic field of the permanent magnets on the structure of water and water-containing systems. It was found that the magnetization of both distilled water and «Karachinskaya» mineral water increase their structuredness. Magnetization changes the biological properties of therapeutic peloids by virtue of a change in the structure of water and, accordingly, the structuring of the water fraction of therapeutic muds...
May 21, 2018: Voprosy Kurortologii, Fizioterapii, i Lechebnoĭ Fizicheskoĭ Kultury
N I Schastnaya, V S Ulashchyk
BACKGROUND: in spite of the fact that photomagnetic therapy with the use of the FotoSPOK device (Magnomed Ltd., Belarus) is already used in the medical practice, the application of this method for the management of many diseases remains to be substantiated on the scientifically sound grounds. AIM: The objective of the present study was to evaluate the effectiveness of photomagnetic therapy in the treatment of the local inflammatory process in the skin and to elaborate the rationale for the application of this technique in the treatment of contact dermatitis...
May 21, 2018: Voprosy Kurortologii, Fizioterapii, i Lechebnoĭ Fizicheskoĭ Kultury
Bram van Asselen, Simon J Woodings, Sara L Hackett, Theo L van Soest, Jan G M Kok, Bas W Raaymakers, Jochem W H Wolthaus
A generic formalism is proposed for reference dosimetry in the presence of a magnetic field. Besides the regular correction factors from the conventional reference dosimetry formalisms, two factors are used to take into account magnetic field effects: 1) a dose conversion factor to correct for the change in local dose distribution and 2) a correction of the reading of the dosimeter used for the reference dosimetry measurements. The formalism was applied to the Elekta MRI-Linac, for which the 1.5 T magnetic field is orthogonal to the 7 MV photon beam...
May 22, 2018: Physics in Medicine and Biology
Shaodong Hu, Annie Gagnoud, Yves Fautrelle, Rene Moreau, Xi Li
Aluminum alloy in situ functionally graded materials (FGMs) have been successfully fabricated using directional solidification under an axial static magnetic field. Al-Zn, Al-Ni and Al-Cu alloys with a hypereutectic composition were selected to produce FGMs. Experimental results show that the graded composition of the primary phases (i.e., Zn, Al3 Ni and Al2 Cu) is obvious along the longitudinal section of the sample. The graded composition of the primary phases could be controlled by the value of the magnetic field, growth rate and temperature gradient...
May 21, 2018: Scientific Reports
Shenggen Yao, Thomas G Meikle, Ashish Sethi, Frances Separovic, Jeffrey J Babon, David W Keizer
Pulsed-field gradient nuclear magnetic resonance has seen an increase in applications spanning a broad range of disciplines where molecular translational diffusion properties are of interest. The current study introduces and experimentally evaluates the measurement of translational diffusion coefficients of 15 N-enriched biomolecules using a 1 H-15 N HMQC-filtered band-selective excitation short transient (BEST) sequence as an alternative to the previously described SOFAST-XSTE sequence. The results demonstrate that accurate translational diffusion coefficients of 15 N-labelled peptides and proteins can be obtained using this alternative 1 H-15 N HMQC-filtered BEST sequence which is implementable on NMR spectrometers equipped with probes fitted with a single-axis field gradient, including most cryoprobes dedicated to bio-NMR...
May 21, 2018: European Biophysics Journal: EBJ
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