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Multiple quantum coherence

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https://www.readbyqxmd.com/read/28613884/carbohydrate-polypeptide-contacts-in-the-antibody-receptor-cd16a-identified-through-solution-nmr-spectroscopy
#1
Ganesh P Subedi, Daniel J Falconer, Adam W Barb
Asparagine-linked carbohydrates (N-glycans) are a common modification of eukaryotic proteins that confer multiple properties including the essential stabilization of therapeutic monoclonal antibodies. Here we present a rapid and efficient strategy to identify N-glycans that contact polypeptide residues and apply the method to profile the five N-glycans attached to the human antibody receptor CD16A (Fc gamma receptor IIIA). Human embryonic kidney 293S cells expressed CD16A with [13CU]-labeled N-glycans using standard protein expression techniques and medium supplemented with 3 g/L [13CU]-glucose...
June 14, 2017: Biochemistry
https://www.readbyqxmd.com/read/28581812/additive-classical-capacity-of-quantum-channels-assisted-by-noisy-entanglement
#2
Quntao Zhuang, Elton Yechao Zhu, Peter W Shor
We give a capacity formula for the classical information transmission over a noisy quantum channel, with separable encoding by the sender and limited resources provided by the receiver's preshared ancilla. Instead of a pure state, we consider the signal-ancilla pair in a mixed state, purified by a "witness." Thus, the signal-witness correlation limits the resource available from the signal-ancilla correlation. Our formula characterizes the utility of different forms of resources, including noisy or limited entanglement assistance, for classical communication...
May 19, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28569753/ultrafast-terahertz-snapshots-of-excitonic-rydberg-states-and-electronic-coherence-in-an-organometal-halide-perovskite
#3
Liang Luo, Long Men, Zhaoyu Liu, Yaroslav Mudryk, Xin Zhao, Yongxin Yao, Joong M Park, Ruth Shinar, Joseph Shinar, Kai-Ming Ho, Ilias E Perakis, Javier Vela, Jigang Wang
How photoexcitations evolve into Coulomb-bound electron and hole pairs, called excitons, and unbound charge carriers is a key cross-cutting issue in photovoltaics and optoelectronics. Until now, the initial quantum dynamics following photoexcitation remains elusive in the hybrid perovskite system. Here we reveal excitonic Rydberg states with distinct formation pathways by observing the multiple resonant, internal quantum transitions using ultrafast terahertz quasi-particle transport. Nonequilibrium emergent states evolve with a complex co-existence of excitons, carriers and phonons, where a delayed buildup of excitons under on- and off-resonant pumping conditions allows us to distinguish between the loss of electronic coherence and hot state cooling processes...
June 1, 2017: Nature Communications
https://www.readbyqxmd.com/read/28558273/evolution-of-multiple-quantum-coherences-with-scaled-dipolar-hamiltonian
#4
Claudia M Sánchez, Lisandro Buljubasich, Horacio M Pastawski, Ana K Chattah
In this article, we introduce a pulse sequence which allows the monitoring of multiple quantum coherences distribution of correlated spin states developed with scaled dipolar Hamiltonian. The pulse sequence is a modification of our previous Proportionally Refocused Loschmidt echo (PRL echo) with phase increment, in order to verify the accuracy of the weighted coherent quantum dynamics. The experiments were carried out with different scaling factors to analyze the evolution of the total magnetization, the time dependence of the multiple quantum coherence orders, and the development of correlated spins clusters...
May 20, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28527462/low-power-broadband-solid-state-mas-nmr-of-14-n
#5
Andrew J Pell, Kevin J Sanders, Sebastian Wegner, Guido Pintacuda, Clare P Grey
We propose two broadband pulse schemes for (14)N solid-state magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) that achieves (i) complete population inversion and (ii) efficient excitation of the double-quantum spectrum using low-power single-sideband-selective pulses. We give a comprehensive theoretical description of both schemes using a common framework that is based on the jolting-frame formalism of Caravatti et al. [J. Magn. Reson. 55, 88 (1983)]. This formalism is used to determine for the first time that we can obtain complete population inversion of (14)N under low-power conditions, which we do here using single-sideband-selective adiabatic pulses...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28393853/continuous-variable-quantum-authentication-of-physical-unclonable-keys
#6
Georgios M Nikolopoulos, Eleni Diamanti
We propose a scheme for authentication of physical keys that are materialized by optical multiple-scattering media. The authentication relies on the optical response of the key when probed by randomly selected coherent states of light, and the use of standard wavefront-shaping techniques that direct the scattered photons coherently to a specific target mode at the output. The quadratures of the electromagnetic field of the scattered light at the target mode are analysed using a homodyne detection scheme, and the acceptance or rejection of the key is decided upon the outcomes of the measurements...
April 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28375700/applications-of-the-new-family-of-coherent-multidimensional-spectroscopies-for-analytical-chemistry
#7
John C Wright
A new family of vibrational and electronic spectroscopies has emerged, comprising the coherent analogs of traditional analytical methods. These methods are also analogs of coherent multidimensional nuclear magnetic resonance (NMR) spectroscopy. This new family is based on creating the same quantum mechanical superposition states called multiple quantum coherences (MQCs). NMR MQCs are mixtures of nuclear spin states that retain their quantum mechanical phase information for milliseconds. The MQCs in this new family are mixtures of vibrational and electronic states that retain their phases for picoseconds or shorter times...
June 12, 2017: Annual Review of Analytical Chemistry
https://www.readbyqxmd.com/read/28334529/ballistic-one-dimensional-inas-nanowire-cross-junction-interconnects
#8
Johannes Gooth, Mattias Borg, Heinz Schmid, Vanessa Schaller, Stephan Wirths, Kirsten Moselund, Mathieu Luisier, Siegfried Karg, Heike Riel
Coherent interconnection of quantum bits remains an ongoing challenge in quantum information technology. Envisioned hardware to achieve this goal is based on semiconductor nanowire (NW) circuits, comprising individual NW devices that are linked through ballistic interconnects. However, maintaining the sensitive ballistic conduction and confinement conditions across NW intersections is a nontrivial problem. Here, we go beyond the characterization of a single NW device and demonstrate ballistic one-dimensional (1D) quantum transport in InAs NW cross-junctions, monolithically integrated on Si...
March 27, 2017: Nano Letters
https://www.readbyqxmd.com/read/28319388/visualizing-intramolecular-vibrational-redistribution-in-cyclotrimethylene-trinitramine-rdx-crystals-by-multiplex-coherent-anti-stokes-raman-scattering
#9
Guoyang Yu, Yangyang Zeng, Wencan Guo, Honglin Wu, Gangbei Zhu, Zhaoyang Zheng, Xianxu Zheng, Yunfei Song, Yanqiang Yang
The femtosecond time-resolved multiplex coherent anti-Stokes Raman scattering (CARS) technique has been performed to investigate intramolecular vibrational redistribution (IVR) through vibrational couplings in 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) molecules. In the multiplex CARS experiment, the supercontinuum (SC) was used as broad-band Stokes light to coherently and collectively excite multiple vibrational modes, and quantum beats arising from vibrational couplings among these modes were observed. The IVR of RDX is visualized by a topological graph of these vibrational couplings, and with analysis of the topological graph, two vibrational modes, both of which are assigned to ring bending, are confirmed to have coupling interactions with most of the other vibrational modes and are considered to have a tendency of energy transfer with these vibrational modes...
March 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28297938/extracting-trajectory-equations-of-classical-periodic-orbits-from-the-quantum-eigenmodes-in-two-dimensional-integrable-billiards
#10
Y H Hsieh, Y T Yu, P H Tuan, J C Tung, K F Huang, Y F Chen
The trajectory equations for classical periodic orbits in the equilateral-triangular and circular billiards are systematically extracted from quantum stationary coherent states. The relationship between the phase factors of quantum stationary coherent states and the initial positions of classical periodic orbits is analytically derived. In addition, the stationary coherent states with noncoprime parametric numbers are shown to correspond to the multiple periodic orbits, which cannot be explicable in the one-particle picture...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28250346/an-efficient-strategy-for-the-synthesis-of-1-trifluoromethylsulfonamido-propan-2-yl-esters-and-the-evaluation-of-their-cytotoxic-activity
#11
Omar Gómez-García, Elizabeth Gómez, César Monzón-González, Teresa Ramírez-Apan, Cecilio Álvarez-Toledano
An efficient method for the synthesis of 1-(trifluoromethylsulfonamido)propan-2-yl benzoates is described, the products of the reaction were characterized by heteronuclear single quantum coherence spectroscopy (HSQC), heteronuclear multiple bond correlation (HMBC) and NMR experiments. The overall process began with the activation of the oxazoline ring by triflic anhydride, followed by the opening of the five-membered ring in the 5-methyl-2-phenyl-4,5-dihydrooxazole system. The cytotoxic activity of the new trifluoromethyl sulfonamides was evaluated with six cancer cell lines and human gingival fibroblasts, posteriorly analyzing the influence on cytotoxicity exerted by the withdrawing and donor substituents at the para-position of the phenyl ring...
2017: Chemical & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/28193069/comprehensive-metabolite-identification-strategy-using-multiple-two-dimensional-nmr-spectra-of-a-complex-mixture-implemented-in-the-colmarm-web-server
#12
Kerem Bingol, Da-Wei Li, Bo Zhang, Rafael Brüschweiler
Identification of metabolites in complex mixtures represents a key step in metabolomics. A new strategy is introduced, which is implemented in a new public web server, COLMARm, that permits the coanalysis of up to three two-dimensional (2D) NMR spectra, namely, (13)C-(1)H HSQC (heteronuclear single quantum coherence spectroscopy), (1)H-(1)H TOCSY (total correlation spectroscopy), and (13)C-(1)H HSQC-TOCSY, for the comprehensive, accurate, and efficient performance of this task. The highly versatile and interactive nature of COLMARm permits its application to a wide range of metabolomics samples independent of the magnetic field...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28157561/indirect-detection-of-infinite-speed-mas-solid-state-nmr-spectra
#13
Frédéric A Perras, Amrit Venkatesh, Michael P Hanrahan, Tian Wei Goh, Wenyu Huang, Aaron J Rossini, Marek Pruski
Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. To address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic (1)H chemical shifts to the indirectly detected isotropic "infinite-MAS" spectra of heavy spin-1/2 nuclides...
January 18, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28155852/electron-transport-in-ultra-thin-films-and-ballistic-electron-emission-microscopy
#14
Y Claveau, S Di Matteo, P L de Andres, F Flores
We have developed a calculation scheme for the elastic electron current in ultra-thin epitaxial heterostructures. Our model uses a Keldysh's non-equilibrium Green's function formalism and a layer-by-layer construction of the epitaxial film. Such an approach is appropriate to describe the current in a ballistic electron emission microscope (BEEM) where the metal base layer is ultra-thin and generalizes a previous one based on a decimation technique appropriated for thick slabs. This formalism allows a full quantum mechanical description of the transmission across the epitaxial heterostructure interface, including multiple scattering via the Dyson equation, which is deemed a crucial ingredient to describe interfaces of ultra-thin layers properly in the future...
March 22, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28154422/coherent-control-of-quasi-degenerate-stationary-like-states-via-multiple-resonances
#15
Yunrong Luo, Kuo Hai, Mingliang Zou, Wenhua Hai
We use three bosons held in a depth-tilt combined-modulated double-well to study coherent control of quantum transitions between quasi-degenerate stationary-like states (QDSLSs) with the same quasienergy. Within the high-frequency approximation and for multiple-resonance conditions, we analytically obtain the different QDSLSs including the maximal bipartite entangled states, which enable us to manipulate the transitions between QDSLSs without the observable multiphoton absorption and to simulate a two-qubit system with the considered bosons...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28146121/a-novel-diterpene-glycoside-with-nine-glucose-units-from-stevia-rebaudiana-bertoni
#16
Indra Prakash, Gil Ma, Cynthia Bunders, Romila D Charan, Catherine Ramirez, Krishna P Devkota, Tara M Snyder
Following our interest in new diterpene glycosides with better taste profiles than that of Rebaudioside M, we have recently isolated and characterized Rebaudioside IX-a novel steviol glycoside-from a commercially-supplied extract of Stevia rebaudiana Bertoni. This molecule contains a hexasaccharide group attached at C-13 of the central diterpene core, and contains three additional glucose units when compared with Rebaudioside M. Here we report the complete structure elucidation-based on extensive Nuclear Magnetic Resonance (NMR) analysis (1H, 13C, Correlation Spectroscopy (COSY), Heteronuclear Single Quantum Coherence-Distortionless Enhancement Polarization Transfer (HSQC-DEPT), Heteronuclear Multiple Bond Correlation (HMBC), 1D Total Correlation Spectroscopy (TOCSY), Nuclear Overhauser Effect Spectroscopy (NOESY)) and mass spectral data-of this novel diterpene glycoside with nine sugar moieties and containing a relatively rare 16 α-linked glycoside...
January 31, 2017: Biomolecules
https://www.readbyqxmd.com/read/28034791/1d-spectral-editing-and-2d-multispectral-in%C3%A2-vivo-1-h-mrs-and-1-h-mrsi-methods-and-applications
#17
Wolfgang Bogner, Gilbert Hangel, Morteza Esmaeili, Ovidiu C Andronesi
This article reviews the methodological aspects of detecting low-abundant J-coupled metabolites via 1D spectral editing techniques and 2D nuclear magnetic resonance (NMR) methods applied in vivo, in humans, with a focus on the brain. A brief explanation of the basics of J-evolution will be followed by an introduction to 1D spectral editing techniques (e.g., J-difference editing, multiple quantum coherence filtering) and 2D-NMR methods (e.g., correlation spectroscopy, J-resolved spectroscopy). Established and recently developed methods will be discussed and the most commonly edited J-coupled metabolites (e...
December 26, 2016: Analytical Biochemistry
https://www.readbyqxmd.com/read/27964895/spin-locking-of-half-integer-quadrupolar-nuclei-in-nmr-of-solids-the-far-off-resonance-case
#18
Smita Odedra, Stephen Wimperis
Spin-locking of spin I=3/2 and I=5/2 nuclei in the presence of large resonance offsets has been studied using both approximate and exact theoretical approaches and, in the case of I=3/2, experimentally. We show the variety of coherences and population states produced in a far off-resonance spin-locking NMR experiment (one consisting solely of a spin-locking pulse) and how these vary with the radiofrequency field strength and offset frequency. Under magic angle spinning (MAS) conditions and in the "adiabatic limit", these spin-locked states acquire a time dependence...
November 30, 2016: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/27910789/methoxyflavones-from-new-lingzhi-medicinal-mushroom-ganoderma-lingzhi-agaricomycetes
#19
Kuniyoshi Shimizu, Yhiya M Amen, Satoru Kaifuchi
Ganoderma lingzhi is one of the most famous medicinal fungi in the world. It has been used in folk medicine, especially in East Asian countries. It is also a white-rot fungus with strong wood degradation ability, especially against lignin. Different classes of bioactive natural products have been reported in Ganoderma, including triterpenes, polysaccharides, sterols, and peptides. The triterpenes and polysaccharides are the primary bioactive compounds of Ganoderma. We report for the first time the presence of 3 methoxyflavones as minor constituents in G...
2016: International Journal of Medicinal Mushrooms
https://www.readbyqxmd.com/read/27883061/unravelling-the-dynamical-origin-of-below-and-near-threshold-harmonic-generation-of-h2-in-an-intense-nir-laser-field
#20
John Heslar, Shih-I Chu
Recently, the study of near- and below- threshold regime harmonics as a potential source of intense coherent vacuum-ultraviolet radiation has received considerable attention. However, the dynamical origin of these lower harmonics, particularly for the molecular systems, is less understood and largely unexplored. Here we perform the first fully ab initio and high precision 3D quantum study of the below- and near-threshold harmonic generation of molecules in an intense 800-nm near-infrared (NIR) laser field. Combining with a synchrosqueezing transform of the quantum time-frequency spectrum and an extended semiclassical analysis, we explore in-depth the roles of various quantum trajectories, including short- and long trajectories, multiphoton trajectories, resonance-enhanced trajectories, and multiple rescattering trajectories of the below- and near- threshold harmonic generation processes...
November 24, 2016: Scientific Reports
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