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https://www.readbyqxmd.com/read/28306267/multiband-one-dimensional-electronic-structure-and-spectroscopic-signature-of-tomonaga-luttinger-liquid-behavior-in-k_-2-cr_-3-as_-3
#1
M D Watson, Y Feng, C W Nicholson, C Monney, J M Riley, H Iwasawa, K Refson, V Sacksteder, D T Adroja, J Zhao, M Hoesch
We present angle-resolved photoemission spectroscopy measurements of the quasi-one-dimensional superconductor K_{2}Cr_{3}As_{3}. We find that the Fermi surface contains two Fermi surface sheets, with linearly dispersing bands not displaying any significant band renormalizations. The one-dimensional band dispersions display a suppression of spectral intensity approaching the Fermi level according to a linear power law, over an energy range of ∼200  meV. This is interpreted as a signature of Tomonoga-Luttinger liquid physics, which provides a new perspective on the possibly unconventional superconductivity in this family of compounds...
March 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28287140/multicolor-emission-from-intermediate-band-semiconductor-zno1-xsex
#2
M Welna, M Baranowski, W M Linhart, R Kudrawiec, K M Yu, M Mayer, W Walukiewicz
Photoluminescence and photomodulated reflectivity measurements of ZnOSe alloys are used to demonstrate a splitting of the valence band due to the band anticrossing interaction between localized Se states and the extended valence band states of the host ZnO matrix. A strong multiband emission associated with optical transitions from the conduction band to lower E- and upper E+ valence subbands has been observed at room temperature. The composition dependence of the optical transition energies is well explained by the electronic band structure calculated using the kp method combined with the band anticrossing model...
March 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28254457/high-sensitivity-tms-fmri-of-the-human-motor-cortex-using-a-dedicated-multichannel-mr-coil
#3
Lucia I Navarro de Lara, Martin Tik, Michael Woletz, Roberta Frass-Kriegl, Ewald Moser, Elmar Laistler, Christian Windischberger
PURPOSE: To validate a novel setup for concurrent TMS/fMRI in the human motor cortex based on a dedicated, ultra-thin, multichannel receive MR coil positioned between scalp and TMS system providing greatly enhanced sensitivity compared to the standard birdcage coil setting. METHODS: A combined TMS/fMRI design was applied over the primary motor cortex based on 1Hz stimulation with stimulation levels of 80%, 90%, 100%, and 110% of the individual active motor threshold, respectively...
February 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/28254338/controlled-co-release-of-doxorubicin-and-reactive-oxygen-species-for-synergistic-therapy-by-nir-remote-triggered-nanoimpellers
#4
Beibei Hou, Weitao Yang, Chunhong Dong, Bin Zheng, Ying Zhang, Jing Wu, Hanjie Wang, Jin Chang
How to encapsulate and transport the payload of multiple therapeutic compounds avoiding premature leakage, and simultaneously co-release them rapidly at specific lesions still remains the major concern in clinic. Herein, we designed the UCN@mSiO2-(Azo+RB) (azobenzene groups and Rose Bengal) nanoimpellers, which used the multicolor-emission capability of the core-shell upconverting nanoparticles (UCNs) at a single excitation wavelength to co-release anticarcinogen doxorubicin (Dox) and reactive oxygen species (ROS) for combined chemotherapy and photodynamic therapy (PDT)...
May 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28253268/multiband-multi-echo-imaging-of-simultaneous-oxygenation-and-flow-timeseries-for-resting-state-connectivity
#5
Alexander D Cohen, Andrew S Nencka, R Marc Lebel, Yang Wang
A novel sequence has been introduced that combines multiband imaging with a multi-echo acquisition for simultaneous high spatial resolution pseudo-continuous arterial spin labeling (ASL) and blood-oxygenation-level dependent (BOLD) echo-planar imaging (MBME ASL/BOLD). Resting-state connectivity in healthy adult subjects was assessed using this sequence. Four echoes were acquired with a multiband acceleration of four, in order to increase spatial resolution, shorten repetition time, and reduce slice-timing effects on the ASL signal...
2017: PloS One
https://www.readbyqxmd.com/read/28242315/individual-differences-and-time-varying-features-of-modular-brain-architecture
#6
Xuhong Liao, Miao Cao, Mingrui Xia, Yong He
Recent studies have suggested that human brain functional networks are topologically organized into functionally specialized but inter-connected modules to facilitate efficient information processing and highly flexible cognitive function. However, these studies have mainly focused on group-level network modularity analyses using "static" functional connectivity approaches. How these extraordinary modular brain structures vary across individuals and spontaneously reconfigure over time remain largely unknown...
February 24, 2017: NeuroImage
https://www.readbyqxmd.com/read/28198576/a-constrained-slice-dependent-background-suppression-scheme-for-simultaneous-multislice-pseudo-continuous-arterial-spin-labeling
#7
Xingfeng Shao, Yi Wang, Steen Moeller, Danny J J Wang
PURPOSE: To present a constrained slice-dependent (CSD) background-suppression (BS) scheme in 2D arterial spin labeling (ASL) using simultaneous multislice acquisition with blipped-CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration). METHODS: Background suppression for 2D acquisition is challenging because of the multiple nulling points required for sequential slice readout. Constrained slice-dependent BS exploits the simultaneous multislice technique to reduce the readout duration, and uses slice-dependent premodulation pulses to achieve BS across slice groups...
February 15, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28179804/quickest-sequential-multiband-spectrum-sensing-with-mixed-observations
#8
Jun Geng, Weiyu Xu, Lifeng Lai
Spectrum sensing is a key technology enabling the cognitive radio system. In this paper, the problem of how to quickly and accurately find an unoccupied channel from a large amount of potential channels is considered. The cognitive radio system under consideration is equipped with a narrow band sensor, hence it can only sense those potential channels in a sequential manner. In this scenario, we propose a novel two-stage mixed-observation sensing strategy. In the first stage, which is named as scanning stage, the sensor observes a linear combination of the signals from a pair of channels...
November 15, 2016: IEEE Transactions on Signal Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28146522/segmented-waveguide-arrays-deriving-discrete-diffraction-relations-in-a-square-lattice-photonic-crystal
#9
C Minot, J M Moison, S Guilet, E Cambril, A Levenson, N Belabas
Segmented strip-loaded waveguide arrays are investigated within a rigorous square lattice photonic crystal model. We derive a full multiband discrete diffraction approach for near-axial injection in the direction of a lattice vector. We obtain an effective waveguide array picture, with quasi-linear dependence on the segmentation ratio in a simplified single-band scheme. Our results are validated by beam deviation experiments. Such a diffraction framework allows for efficient shaping of the phase map in waveguide arrays and enriches the engineering toolkit of photonic crystals with the in-plane free propagation structures of discrete photonics...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28135102/multiband-hot-photoluminescence-from-nanocavity-embedded-silicon-nanowire-arrays-with-tunable-wavelength
#10
Zhiqiang Mu, Haochi Yu, Miao Zhang, Aimin Wu, Gongmin Qi, Paul K Chu, Zhenghua An, Zengfeng Di, Xi Wang
Besides the well-known quantum confinement effect, hot luminescence from indirect bandgap Si provides a new and promising approach to realize monolithically integrated silicon optoelectronics due to phonon-assisted light emission. In this work, multiband hot photoluminescence is generated from Si nanowire arrays by introducing trapezoid-shaped nanocavities that support hybrid photonic-plasmonic modes. By continuously adjusting the geometric parameters of the Si nanowires with trapezoidal nanocavities, the multiband hot photoluminescence can be tuned in the range from visible to near-infrared independent of the excitation laser wavelength...
March 8, 2017: Nano Letters
https://www.readbyqxmd.com/read/28097733/optimized-amplitude-modulated-multiband-rf-pulse-design
#11
Samy Abo Seada, Anthony N Price, Joseph V Hajnal, Shaihan J Malik
PURPOSE: Multiband pulses are characterized by highly temporally modulated waveforms. Rapid phase or frequency modulation can be extremely demanding on the performance of radiofrequency (RF) pulse generation, which can lead to errors that can be avoided if pulses are restricted to amplitude modulation (AM) only. In this work, three existing multiband pulse design techniques are modified to produce AM waveforms. THEORY AND METHODS: Multiband refocusing pulses were designed using phase optimization, time shifting, and root flipping...
January 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28071599/unsupervised-frequency-recognition-method-of-ssveps-using-a-filter-bank-implementation-of-binary-subband-cca
#12
Md Rabiul Islam, Md Khademul Islam Molla, Masaki Nakanishi, Toshihisa Tanaka
OBJECTIVE: Recently developed effective methods for detection commands of steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) that need calibration for visual stimuli, which cause more time and fatigue prior to the use, as the number of commands increases. This paper develops a novel unsupervised method based on canonical correlation analysis (CCA) for accurate detection of stimulus frequency. APPROACH: A novel unsupervised technique termed as binary subband CCA (BsCCA) is implemented in a multiband approach to enhance the frequency recognition performance of SSVEP...
April 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28036201/probing-the-pairing-interaction-and-multiple-bardasis-schrieffer-modes-using-raman-spectroscopy
#13
S Maiti, T A Maier, T Böhm, R Hackl, P J Hirschfeld
In unconventional superconductors, understanding the form of the pairing interaction is the primary goal. In this regard, Raman spectroscopy is a very useful tool, as it identifies the ground state and also the subleading pairing channels by probing collective modes. Here, we propose a general theory for a multiband Raman response and identify new features in the spectrum that can provide a robust test for a pairing theory. We identify multiple Bardasis-Schrieffer type collective modes and connect the weights of these modes to the subleading gap structures within a microscopic pairing theory...
December 16, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/28019022/use-of-pattern-recognition-for-unaliasing-simultaneously-acquired-slices-in-simultaneous-multislice-mr-fingerprinting
#14
Yun Jiang, Dan Ma, Himanshu Bhat, Huihui Ye, Stephen F Cauley, Lawrence L Wald, Kawin Setsompop, Mark A Griswold
PURPOSE: The purpose of this study is to accelerate an MR fingerprinting (MRF) acquisition by using a simultaneous multislice method. METHODS: A multiband radiofrequency (RF) pulse was designed to excite two slices with different flip angles and phases. The signals of two slices were driven to be as orthogonal as possible. The mixed and undersampled MRF signal was matched to two dictionaries to retrieve T1 and T2 maps of each slice. Quantitative results from the proposed method were validated with the gold-standard spin echo methods in a phantom...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27934949/giant-magnetoresistance-three-dimensional-fermi-surface-and-origin-of-resistivity-plateau-in-ysb-semimetal
#15
Orest Pavlosiuk, Przemysław Swatek, Piotr Wiśniewski
Very strong magnetoresistance and a resistivity plateau impeding low temperature divergence due to insulating bulk are hallmarks of topological insulators and are also present in topological semimetals where the plateau is induced by magnetic field, when time-reversal symmetry (protecting surface states in topological insulators) is broken. Similar features were observed in a simple rock-salt-structure LaSb, leading to a suggestion of the possible non-trivial topology of 2D states in this compound. We show that its sister compound YSb is also characterized by giant magnetoresistance exceeding one thousand percent and low-temperature plateau of resistivity...
December 9, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27894889/tradeoffs-in-pushing-the-spatial-resolution-of-fmri-for-the-7t-human-connectome-project
#16
An Thanh Vu, Keith Jamison, Matthew F Glasser, Stephen M Smith, Timothy Coalson, Steen Moeller, Edward J Auerbach, Kamil Uğurbil, Essa Yacoub
Whole-brain functional magnetic resonance imaging (fMRI), in conjunction with multiband acceleration, has played an important role in mapping the functional connectivity throughout the entire brain with both high temporal and spatial resolution. Ultrahigh magnetic field strengths (7T and above) allow functional imaging with even higher functional contrast-to-noise ratios for improved spatial resolution and specificity compared to traditional field strengths (1.5T and 3T). High-resolution 7T fMRI, however, has primarily been constrained to smaller brain regions given the amount of time it takes to acquire the number of slices necessary for high resolution whole brain imaging...
November 25, 2016: NeuroImage
https://www.readbyqxmd.com/read/27851870/sms-hsl-simultaneous-multislice-aliasing-separation-exploiting-hankel-subspace-learning
#17
Suhyung Park, Jaeseok Park
PURPOSE: To develop a novel, simultaneous multislice reconstruction method that exploits Hankel subspace learning (SMS-HSL) for aliasing separation in the slice direction. METHODS: An SMS signal model with the Hankel-structured matrix was proposed. To efficiently suppress interslice leakage artifacts from a signal subspace perspective, a null space was learned from the reference data combined over all slices other than a slice of interest using singular value decomposition...
November 8, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27828509/design-of-triple-band-metamaterial-absorbers-with-refractive-index-sensitivity-at-infrared-frequencies
#18
Jie Xu, Ziyi Zhao, Haochi Yu, Le Yang, Peng Gou, Jun Cao, Yuexin Zou, Jie Qian, Tianjun Shi, Qijun Ren, Zhenghua An
A triple-band perfect plasmonic metamaterial absorber based on a metal/insulator/metal (MIM) structure is designed. A new freedom through tuning the thicknesses of each ring structures is introduced to realize a quasi-three-dimensional perfect absorber at three extinction wavelengths by using the finite difference time domain method. The physical machine is explained by the time domain field analyses and the coupled mode theory. The characteristics of the absorber make our proposed strategy applicable for the design of more general multiband and broadband perfect absorbers...
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27790754/advancing-rf-pulse-design-using-an-open-competition-format-report-from-the-2015-ismrm-challenge
#19
William A Grissom, Kawin Setsompop, Samuel A Hurley, Jeffrey Tsao, Julia V Velikina, Alexey A Samsonov
PURPOSE: To advance the best solutions to two important RF pulse design problems with an open head-to-head competition. METHODS: Two sub-challenges were formulated in which contestants competed to design the shortest simultaneous multislice (SMS) refocusing pulses and slice-selective parallel transmission (pTx) excitation pulses, subject to realistic hardware and safety constraints. Short refocusing pulses are needed for spin echo SMS imaging at high multiband factors, and short slice-selective pTx pulses are needed for multislice imaging in ultra-high field MRI...
October 27, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27770478/deriving-frequency-dependent-spatial-patterns-in-meg-derived-resting-state-sensorimotor-network-a-novel-multiband-ica-technique
#20
Allison C Nugent, Bruce Luber, Frederick W Carver, Stephen E Robinson, Richard Coppola, Carlos A Zarate
Recently, independent components analysis (ICA) of resting state magnetoencephalography (MEG) recordings has revealed resting state networks (RSNs) that exhibit fluctuations of band-limited power envelopes. Most of the work in this area has concentrated on networks derived from the power envelope of beta bandpass-filtered data. Although research has demonstrated that most networks show maximal correlation in the beta band, little is known about how spatial patterns of correlations may differ across frequencies...
February 2017: Human Brain Mapping
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