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Multiple quantum coherence

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
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
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
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
Guoxing Lin
Anomalous diffusion exists widely in polymer and biological systems. Pulsed-field gradient (PFG) techniques have been increasingly used to study anomalous diffusion in nuclear magnetic resonance and magnetic resonance imaging. However, the interpretation of PFG anomalous diffusion is complicated. Moreover, the exact signal attenuation expression including the finite gradient pulse width effect has not been obtained based on fractional derivatives for PFG anomalous diffusion. In this paper, a new method, a Mainardi-Luchko-Pagnini (MLP) phase distribution approximation, is proposed to describe PFG fractional diffusion...
November 21, 2016: Journal of Chemical Physics
Yuta Mizuno, Yasuki Arasaki, Kazuo Takatsuka
We propose a theoretical principle to directly monitor the bifurcation of quantum wavepackets passing through nonadiabatic regions of a molecule that is placed in intense continuous wave (CW) laser fields. This idea makes use of the phenomenon of laser-driven photon emission from molecules that can undergo nonadiabatic transitions between ionic and covalent potential energy surfaces like Li(+) F(-) and LiF. The resultant photon emission spectra are of anomalous yet characteristic frequency and intensity, if pumped to an energy level in which the nonadiabatic region is accessible and placed in a CW laser field...
November 14, 2016: Journal of Chemical Physics
Christof Drechsel-Grau, Dominik Marx
The transfer of multiple protons in hydrogen-bonded networks usually occurs one proton at a time. At sufficiently high temperatures, each proton transfers via thermally activated hopping along its hydrogen bond, thereby moving a charge defect through the network. At low temperatures, quantum-mechanical tunnelling might set in instead, thus avoiding hopping over the energy barriers. In the case of several transferring protons, independent thermal hopping or quantum tunnelling of the individual protons becomes less favourable because of a significant creation of charge defects...
November 7, 2016: Physical Chemistry Chemical Physics: PCCP
Beata Morak-Młodawska, Krystian Pluta, Małgorzata Latocha, Małgorzata Jeleń
New phenothiazine derivatives as 10-substituted dipyridothiazines of the 1,6-diazaphenothiazine structure were obtained in the cyclization reaction of 3-amino-3'-nitro-2,2'-dipyridinyl sulfide and 3,3'-dinitro-2,2'-dipyridinyl disulfide, and in the reaction of 2-chloro-3-ntropyridine with sodium 3-amino-2-pyridinethiolate followed by various alkylation and arylation reactions. The reaction of the thiazine ring formation ran via the Smiles rearrangement of the S-N type. As the alkylation reactions could proceed at the thiazine, azine or both nitrogen atoms, the product structure elucidation was based on the 2D NMR (Rotating-frame Overhauser Effect Spectroscopy, Correlated Spectroscopy, Heteronuclear Single Quantum Coherence, and Heteronuclear Multiple Bond Correlation) spectra of the N-methylated product...
2016: Medicinal Chemistry Research
Florence Auberon, Opeyemi Joshua Olatunji, Stéphanie Krisa, Cyril Antheaume, Gaëtan Herbette, Frédéric Bonté, Jean-Michel Mérillon, Annelise Lobstein
Two new phenanthrene derivatives, a phenanthrenequinone named arundiquinone (1) and a 9,10-dihydrophenanthrene named arundigramin (2) together with a known lignin dimer (3) and seven known stilbenoids (4-10) were isolated from the aerial parts of the Asian orchid Arundina graminifolia. The structures of the isolated compounds were elucidated by spectroscopic methods, including extensive 1D, 2D NMR (heteronuclear single quantum coherence (HSQC), heteronuclear multiple-bond correlation spectroscopy (HMBC), and HR-ESI-MS techniques, as well as comparison with respective literature reports...
October 27, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
G N Manjunatha Reddy, Michal Malon, Andrew Marsh, Yusuke Nishiyama, Steven P Brown
A fast magic-angle spinning (MAS, 70 kHz) solid-state NMR experiment is presented that combines (1)H Double-Quantum (DQ) and (14)N-(1)H HMQC (Heteronuclear Multiple-Quantum Coherence) pulse-sequence elements, so as to simultaneously probe H-H and N-H proximities in molecular solids. The proposed experiment can be employed in both two-dimensional (2D) and three-dimensional (3D) versions: first, a 2D (14)N HMQC-filtered (1)H-DQ experiment provides specific DQ-SQ correlation peaks for proton pairs that are in close proximities to the nitrogen sites, thereby achieving spectral filtration...
December 6, 2016: Analytical Chemistry
Hugh D Mitchell, Lye Meng Markillie, William B Chrisler, Matthew J Gaffrey, Dehong Hu, Craig J Szymanski, Yumei Xie, Eric S Melby, Alice Dohnalkova, Ronald C Taylor, Eva K Grate, Scott K Cooley, Jason E McDermott, Alejandro Heredia-Langner, Galya Orr
The impact of distinct nanoparticle (NP) properties on cellular response and ultimately human health is unclear. This gap is partially due to experimental difficulties in achieving uniform NP loads in the studied cells, creating heterogeneous populations with some cells "overloaded" while other cells are loaded with few or no NPs. Yet gene expression studies have been conducted in the population as a whole, identifying generic responses, while missing unique responses due to signal averaging across many cells, each carrying different loads...
November 22, 2016: ACS Nano
Hiroyuki Katsuki, Kenji Ohmori
We have experimentally performed the coherent control of delocalized ro-vibrational wave packets (RVWs) of solid para-hydrogen (p-H2) by the wave packet interferometry (WPI) combined with coherent anti-Stokes Raman scattering (CARS). RVWs of solid p-H2 are delocalized in the crystal, and the wave function with wave vector k ∼ 0 is selectively excited via the stimulated Raman process. We have excited the RVW twice by a pair of femtosecond laser pulses with delay controlled by a stabilized Michelson interferometer...
September 28, 2016: Journal of Chemical Physics
Tsung Sheng Kao, Yu-Hsun Chou, Kuo-Bin Hong, Jiong-Fu Huang, Chun-Hsien Chou, Hao-Chung Kuo, Fang-Chung Chen, Tien-Chang Lu
Solution-processed organic-inorganic perovskites are fascinating due to their remarkable photo-conversion efficiency and great potential in the cost-effective, versatile and large-scale manufacturing of optoelectronic devices. In this paper, we demonstrate that the perovskite nanocrystal sizes can be simply controlled by manipulating the precursor solution concentrations in a two-step sequential deposition process, thus achieving the feasible tunability of excitonic properties and lasing performance in hybrid metal-halide perovskites...
October 25, 2016: Nanoscale
Abou El-Hamd H Mohamed, Naglaa S Mohamed, Ahmed R Hamed, Mohamed-Elamir F Hegazy
In continuation of our chemical investigation on some medicinal plants of the genus Achillea, chromatographic investigation of the methylene chloride/methanol (1:1) extract of the air-dried aerial part of Achillea biebersteinii Afan. (family Asteraceae) afforded a new natural monoterpene (2), in addition to two known sesquiterpenes (3 and 4). Compound 1 was isolated as light needle crystals. Structures were established on the basis of MS and NMR spectroscopic (1H, 13C, 1H-1H correlation spectroscopy, heteronuclear multiple-quantum coherence and heteronuclear multiple-bond correlation) data and in case of compound 1 were confirmed by X-ray analysis...
October 24, 2016: Zeitschrift Für Naturforschung. C, A Journal of Biosciences
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
N Kalb, J Cramer, D J Twitchen, M Markham, R Hanson, T H Taminiau
Repeated observations inhibit the coherent evolution of quantum states through the quantum Zeno effect. In multi-qubit systems this effect provides opportunities to control complex quantum states. Here, we experimentally demonstrate that repeatedly projecting joint observables of multiple spins creates quantum Zeno subspaces and simultaneously suppresses the dephasing caused by a quasi-static environment. We encode up to two logical qubits in these subspaces and show that the enhancement of the dephasing time with increasing number of projections follows a scaling law that is independent of the number of spins involved...
October 7, 2016: Nature Communications
Aleksandra Klimek, Michał Jachura, Wojciech Wasilewski, Konrad Banaszek
We propose a simple architecture based on multimode quantum memories for collective readout of classical information keyed using a pair coherent states, exemplified by the well-known binary phase shift keying format. Such a configuration enables demonstration of the superadditivity effect in classical communication over quantum channels, where the transmission rate becomes enhanced through joint detection applied to multiple channel uses. The proposed scheme relies on the recently introduced idea to prepare Hadamard sequences of input symbols that are mapped by a linear optical transformation onto the pulse position modulation format [Guha, S...
November 12, 2016: Journal of Modern Optics
Xu Han, Chang-Ling Zou, Hong X Tang
High-frequency mechanical resonators subjected to low thermal phonon occupancy are easier to be prepared to the ground state by direct cryogenic cooling. Their extreme stiffness, however, poses a significant challenge for external interrogations. Here we demonstrate a superconducting cavity piezoelectromechanical system in which multiple modes of a bulk acoustic resonator oscillating at 10 GHz are coupled to a planar microwave superconducting resonator with a cooperativity exceeding 2×10^{3}, deep in the strong coupling regime...
September 16, 2016: Physical Review Letters
Lirong Chen, Zhongxiao Xu, Weiqing Zeng, Yafei Wen, Shujing Li, Hai Wang
We report an experiment in which long-lived quantum memories for photonic polarization qubits (PPQs) are controllably released into any one of multiple spatially-separate channels. The PPQs are implemented with an arbitrarily-polarized coherent signal light pulses at the single-photon level and are stored in cold atoms by means of electromagnetic-induced-transparency scheme. Reading laser pulses propagating along the direction at a small angle relative to quantum axis are applied to release the stored PPQs into an output channel...
September 26, 2016: Scientific Reports
Rémy Bertrand Teponno, Chiaki Tanaka, Bai Jie, Léon Azefack Tapondjou, Tomofumi Miyamoto
Four previously unreported steroidal saponins, trifasciatosides A-D (1-4), three pairs of previously undescribed steroidal saponins, trifasciatosides E-J (5a, b-7a, b) including acetylated ones, together with twelve known compounds were isolated from the n-butanol soluble fraction of the methanol extract of Sansevieria trifasciata. Their structures were elucidated on the basis of detailed spectroscopic analysis, including (1)H-NMR, (13)C-NMR, (1)H-(1)H correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC), total correlated spectroscopy (TOCSY), nuclear Overhauser enhancement and exchange spectroscopy (NOESY), electrospray ionization-time of flight (ESI-TOF)-MS and chemical methods...
2016: Chemical & Pharmaceutical Bulletin
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