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Grzegorz Bauman, Francesco Santini, Orso Pusterla, Oliver Bieri
PURPOSE: To present a technique for simultaneous mapping of T1 , T2 , and relative spin density (M0 ) in human lung using inversion recovery ultra-fast steady-state free precession (IR-ufSSFP) imaging. METHODS: Pulmonary relaxometry with IR-ufSSFP is based on an interleaved time series acquisition of 2D images acquired at 1.5T. The technique was tested in a phantom and in four healthy volunteers using breath-hold and electrocardiogram triggering. Typically, 30 transient state images were acquired in a single breath-hold within < 10 s...
October 19, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Le Zhang, Alex Burant, Andrew McCallister, Victor Zhao, Karl M Koshlap, Simone Degan, Michael Antonacci, Rosa Tamara Branca
PURPOSE: To investigate the temperature dependence of the resonance frequency of lipid-dissolved xenon (LDX) and to assess the accuracy of LDX-based MR thermometry. METHODS: The chemical shift temperature dependence of water protons, methylene protons, and LDX was measured from samples containing tissues with varying fat contents using a high-resolution NMR spectrometer. LDX results were then used to acquire relative and absolute temperature maps in vivo and the results were compared with PRF-based MR thermometry...
October 19, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Suman Chowdhury, Debnarayan Jana
Inspired by the success of graphene, various two dimensional (2D) structures in free standing (FS) (hypothetical) form and on different substrates have been proposed recently. Silicene, a silicon counterpart of graphene, is predicted to possess massless Dirac fermions and to exhibit an experimentally accessible quantum spin Hall effect. Since the effective spin-orbit interaction is quite significant compared to graphene, buckling in silicene opens a gap of 1.55 meV at the Dirac point. This band gap can be further tailored by applying in plane stress, an external electric field, chemical functionalization and defects...
October 18, 2016: Reports on Progress in Physics
Albert C Aragonès, Ernesto Medina, Miriam Ferrer-Huerta, Nuria Gimeno, Meritxell Teixidó, Julio L Palma, Nongjian Tao, Jesus M Ugalde, Ernest Giralt, Ismael Díez-Pérez, Vladimiro Mujica
The electronic spin filtering capability of a single chiral helical peptide is measured. A ferromagnetic electrode source is employed to inject spin-polarized electrons in an asymmetric single-molecule junction bridging an α-helical peptide sequence of known chirality. The conductance comparison between both isomers allows the direct determination of the polarization power of an individual chiral molecule.
October 18, 2016: Small
Duygu Tosun, Norbert Schuff, Gil D Rabinovici, Nagehan Ayakta, Bruce L Miller, William Jagust, Joel Kramer, Michael M Weiner, Howard J Rosen
OBJECTIVE: To compare the values of arterial spin-labeled (ASL) MRI and fluorodeoxyglucose (FDG) PET in the diagnosis of behavioral variant of frontotemporal dementia (bvFTD) and Alzheimer's disease (AD). METHODS: Partial least squares logistic regression was used to identify voxels with diagnostic value in cerebral blood flow (CBF) and cerebral metabolic rate of glucose (CMRgl) maps from patients with bvFTD (n = 32) and AD (n = 28), who were compared with each other and with cognitively normal controls (CN, n = 15)...
October 2016: Annals of Clinical and Translational Neurology
A A Baker, A I Figueroa, D Pingstone, V K Lazarov, G van der Laan, T Hesjedal
We present a study of the interaction mechanisms in magnetic trilayer structures with an MgO barrier grown by molecular beam epitaxy. The interlayer exchange coupling, Aex, is determined using SQUID magnetometry and ferromagnetic resonance (FMR), displaying an unexpected oscillatory behaviour as the thickness, tMgO, is increased from 1 to 4 nm. Transmission electron microscopy confirms the continuity and quality of the tunnelling barrier, eliminating the prospect of exchange arising from direct contact between the two ferromagnetic layers...
October 18, 2016: Scientific Reports
Kuen-Lin Chen, Yao-Wei Yeh, Jian-Ming Chen, Yu-Jie Hong, Tsung-Lin Huang, Zu-Yin Deng, Chiu-Hsien Wu, Su-Hsien Liao, Li-Min Wang
Magnetoplasmonic nanoparticles, composed of a plasmonic layer and a magnetic core, have been widely shown as promising contrast agents for magnetic resonance imaging (MRI) applications. However, their application in low-field nuclear magnetic resonance (LFNMR) research remains scarce. Here we synthesised γ-Fe2O3/Au core/shell (γ-Fe2O3@Au) nanoparticles and subsequently used them in a homemade, high-Tc, superconducting quantum interference device (SQUID) LFNMR system. Remarkably, we found that both the proton spin-lattice relaxation time (T1) and proton spin-spin relaxation time (T2) were influenced by the presence of γ-Fe2O3@Au nanoparticles...
October 18, 2016: Scientific Reports
Andrey N Pravdivtsev, Alexey S Kiryutin, Alexandra V Yurkovskaya, Hans-Martin Vieth, Konstantin L Ivanov
We propose a robust and highly efficient NMR technique to create singlet spin order from longitudinal spin magnetization in coupled spin-½ pairs and to perform backward conversion (singlet order)→magnetization. In this method we exploit adiabatic ramping of an RF-field in order to drive transitions between the singlet state and the T± triplet states of a spin pair under study. We demonstrate that the method works perfectly for both strongly and weakly coupled spin pairs, providing a conversion efficiency between the singlet spin order and magnetization, which is equal to the theoretical maximum...
October 6, 2016: Journal of Magnetic Resonance
Quanbo Jiang, Aline Pham, Serge Huant, Joel Bellessa, Cyriaque Genet, Aurélien Drezet
We report a highly efficient generation of singular surface plasmon (SP) fields by an achiral plasmonic structure consisting of Λ-shaped apertures. Our quantitative analysis, based on leakage radiation microscopy (LRM), demonstrates that the induced spin-orbit coupling can be tuned by adjusting the apex angle of the Λ-shaped aperture. Specifically, the array of Λ-shaped apertures with the apex angle 60° is shown to give rise to the directional coupling efficiency. The ring of Λ-shaped apertures with the apex angle 60° was found to generate the maximum extinction ratio (ER=11) for the SP singularities between two different polarization states...
October 1, 2016: Optics Letters
Sudipta Saha, Ankit K Singh, Subir K Ray, Ayan Banerjee, Subhasish Dutta Gupta, Nirmalya Ghosh
We study the near field to the far field evolution of spin angular momentum (SAM) density and the Poynting vector of the scattered waves from spherical scatterers. The results show that at the near field, the SAM density and the Poynting vector are dominated by their transverse components. While the former (transverse SAM) is independent of the helicity of the incident circular polarization state, the latter (transverse Poynting vector) depends upon the polarization state. It is further demonstrated that the interference of the transverse electric and transverse magnetic scattering modes enhances both the magnitudes and the spatial extent of the transverse SAM and the transverse momentum components...
October 1, 2016: Optics Letters
Arne Laucht, Rachpon Kalra, Stephanie Simmons, Juan P Dehollain, Juha T Muhonen, Fahd A Mohiyaddin, Solomon Freer, Fay E Hudson, Kohei M Itoh, David N Jamieson, Jeffrey C McCallum, Andrew S Dzurak, A Morello
Coherent dressing of a quantum two-level system provides access to a new quantum system with improved properties-a different and easily tunable level splitting, faster control and longer coherence times. In our work we investigate the properties of the dressed, donor-bound electron spin in silicon, and assess its potential as a quantum bit in scalable architectures. The two dressed spin-polariton levels constitute a quantum bit that can be coherently driven with an oscillating magnetic field, an oscillating electric field, frequency modulation of the driving field or a simple detuning pulse...
October 17, 2016: Nature Nanotechnology
A Venkatraman, A Khawaja, A K Bag, M Mirza, J P Szaflarski, S Pati
Lateralized Periodic Discharges (LPDs) are commonly seen on EEG in critically-ill patients. They are often associated with seizures, but some patients may have them without seizures. Therefore, they are considered to lie in the ictal-interictal continuum. When ictal, they require multiple antiepileptic drugs to treat effectively, which can expose the patient to iatrogenic complications. Therefore, optimal management is controversial. We present here two cases where perfusion-weighted Magnetic Resonance Imaging (pMRI) was useful in distinguishing ictal from interictal LPDs...
October 5, 2016: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
Félix Beaudoin, Dany Lachance-Quirion, W A Coish, Michel Pioro-Ladrière
Microwave-frequency superconducting resonators are ideally suited to perform dispersive qubit readout, to mediate two-qubit gates, and to shuttle states between distant quantum systems. A prerequisite for these applications is a strong qubit-resonator coupling. Strong coupling between an electron-spin qubit and a microwave resonator can be achieved by correlating spin- and orbital degrees of freedom. This correlation can be achieved through the Zeeman coupling of a single electron in a double quantum dot to a spatially inhomogeneous magnetic field generated by a nearby nanomagnet...
October 17, 2016: Nanotechnology
Craig Waitt, Nashali M Ferrara, Henk Eshuis
The performance of the random phase approximation (RPA) is tested for ther- mochemistry and geometries of transition metal chemistry using various benchmarks obtained either computationally or experimentally. Comparison is made to popular (semi-)local, meta- and hybrid density functionals as well as to second-order Møller- Plesset perturbation theory (MP2) and its spin-component-scaled derivatives. The benchmarks sets include reaction energies, barrier heights and dissociation energies of prototype bond-activation reactions, dissociation energies for a set of large transition metal complexes, bond lengths and dissociation energies of metal hydride ions, and bond lengths and angles of a set of closed-shell first-row transition metal complexes...
October 17, 2016: Journal of Chemical Theory and Computation
Teresa F Mastropietro, Nadia Marino, Giovanni De Munno, Francesc Lloret, Miguel Julve, Emilio Pardo, Donatella Armentano
The preparation and structural characterization of four novel oxalate-based iron(III) compounds of formulas {(MeNH3)2[Fe2(ox)2Cl4]·2.5H2O}n (1), K(MeNH3)[Fe(ox)Cl3(H2O)] (2), {MeNH3[Fe2(OH)(ox)2Cl2]·2H2O}n (3), and {(H3O)(MeNH3)[Fe2O(ox)2Cl2]·3H2O}n (4) (MeNH3(+) = methylammonium cation and H2ox = oxalic acid) are reported here. 1 is an anionic waving chain of oxalato-bridged iron(III) ions with peripheral chloro ligands, the charge balance being ensured by methylammonium cations. 2 is a mononuclear complex with a bidentate oxalate, three terminal chloro ligands, and a coordinated water molecule achieving the six-coordination around each iron(III) ion...
October 17, 2016: Inorganic Chemistry
Elizabeth S Ng, Lisa Azzola, Freya F Bruveris, Vincenzo Calvanese, Belinda Phipson, Katerina Vlahos, Claire Hirst, Vanta J Jokubaitis, Qing C Yu, Jovana Maksimovic, Simone Liebscher, Vania Januar, Zhen Zhang, Brenda Williams, Aude Conscience, Jennifer Durnall, Steven Jackson, Magdaline Costa, David Elliott, David N Haylock, Susan K Nilsson, Richard Saffery, Katja Schenke-Layland, Alicia Oshlack, Hanna K A Mikkola, Edouard G Stanley, Andrew G Elefanty
The ability to generate hematopoietic stem cells from human pluripotent cells would enable many biomedical applications. We find that hematopoietic CD34(+) cells in spin embryoid bodies derived from human embryonic stem cells (hESCs) lack HOXA expression compared with repopulation-competent human cord blood CD34(+) cells, indicating incorrect mesoderm patterning. Using reporter hESC lines to track the endothelial (SOX17) to hematopoietic (RUNX1C) transition that occurs in development, we show that simultaneous modulation of WNT and ACTIVIN signaling yields CD34(+) hematopoietic cells with HOXA expression that more closely resembles that of cord blood...
October 17, 2016: Nature Biotechnology
Michael T McMahon, Assaf A Gilad
Chemical exchange saturation transfer (CEST) is a powerful new tool well suited for molecular imaging. This technology enables the detection of low concentration probes through selective labeling of rapidly exchanging protons or other spins on the probes. In this review, we will highlight the unique features of CEST imaging technology and describe the different types of CEST agents that are suited for molecular imaging studies, including CEST theranostic agents, CEST reporter genes, and CEST environmental sensors...
October 2016: Topics in Magnetic Resonance Imaging: TMRI
Vincent Rampazzi, Julien Roger, Régine Amardeil, Marie-José Penouilh, Philippe Richard, Paul Fleurat-Lessard, Jean-Cyrille Hierso
A smart steric control of the metallocene backbone in bis- and poly(phosphino)ferrocene ligands favors intramolecular aurophilic interactions between [AuCl] fragments in polynuclear gold(I) complexes. We synthesized and characterized by multinuclear NMR and X-ray diffraction analysis mono-, di-, and polynuclear gold complexes of constrained ferrocenyl diphosphines, which bear either bulky tert-butyl groups or more flexible siloxane substituents at the cyclopentadienyl rings. The complexes meso-1,1'-bis(diphenylphosphino)-3,3'-di-tert-butylferrocene (4-m), rac-1,1'-bis[bis(5-methyl-2-furyl)phosphino]-3,3'-di-tert-butylferrocene (5-r), and rac-1,1'-bis(diphenylphosphino)-3,3'-bis[(tri-iso-propylsilyl)oxy]ferrocene (6-r) were used to form dinuclear gold complexes...
October 17, 2016: Inorganic Chemistry
Matvey V Fedin, Georgiy Yu Shevelev, Dmitrii V Pyshnyi, Victor M Tormyshev, Gunnar Jeschke, Maxim Yulikov, Elena G Bagryanskaya
Spin labels selectively attached to biomolecules allow high-accuracy nanoscale distance measurements using pulsed electron paramagnetic resonance (EPR), in many cases providing the only access to the structure of complex biosystems. Triarylmethyl (TAM) radicals have recently emerged as a new class of spin labels expanding the applicability of the method to physiological temperatures. Along with other factors, the accuracy of the obtained distances crucially relies on the understanding of interactions between biomolecules and spin labels...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Belén Sotillo, Vibhav Bharadwaj, J P Hadden, Masaaki Sakakura, Andrea Chiappini, Toney Teddy Fernandez, Stefano Longhi, Ottavia Jedrkiewicz, Yasuhiko Shimotsuma, Luigino Criante, Roberto Osellame, Gianluca Galzerano, Maurizio Ferrari, Kiyotaka Miura, Roberta Ramponi, Paul E Barclay, Shane Michael Eaton
Diamond is a promising platform for sensing and quantum processing owing to the remarkable properties of the nitrogen-vacancy (NV) impurity. The electrons of the NV center, largely localized at the vacancy site, combine to form a spin triplet, which can be polarized with 532 nm laser light, even at room temperature. The NV's states are isolated from environmental perturbations making their spin coherence comparable to trapped ions. An important breakthrough would be in connecting, using waveguides, multiple diamond NVs together optically...
October 17, 2016: Scientific Reports
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