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Alessandro Molle, Joshua Goldberger, Michel Houssa, Yong Xu, Shou-Cheng Zhang, Deji Akinwande
Silicene, germanene and stanene are part of a monoelemental class of two-dimensional (2D) crystals termed 2D-Xenes (X = Si, Ge, Sn and so on) which, together with their ligand-functionalized derivatives referred to as Xanes, are comprised of group IVA atoms arranged in a honeycomb lattice - similar to graphene but with varying degrees of buckling. Their electronic structure ranges from trivial insulators, to semiconductors with tunable gaps, to semi-metallic, depending on the substrate, chemical functionalization and strain...
January 16, 2017: Nature Materials
Chen Zhao, Shiqin Jiang, Yanhua Wu, Junjie Zhu, Dafang Zhou, Birgit Hailer, Dietrich Gronemeyer, Peter Van Leeuwen
We present a new approach of integrated maximum current density (IMCD) for the noninvasive detection of myocardial infarction (MI) using magnetocardiography (MCG) data acquired from a superconducting quantum interference device (SQUID) system. In this study, we investigated the relationship of the maximum current density (MCD) in the current density map and the underlying equivalent current dipole (ECD) based on a novel method of reconstructing the ECD in the extremum circle of the magnetic field map. The performance of IMCD and the integrated ECD (IECD) approaches were also evaluated by using 61-channel MCG data from 39 healthy subjects and 102 patients with ST elevation myocardial infarction (STEMI)...
January 9, 2017: IEEE Journal of Biomedical and Health Informatics
Valeria Loscri, Anna Maria Vegni
Nanotechnology, as enabler of the miniaturization of devices in a scale ranging from 1 to few hundreds of nm , represents a viable solution for " alternative" communication paradigms that could be effective in complex networked systems, as body area networks. Traditional communication paradigms are not effective in the context of joint body and nano-networked systems, for several reasons, and then novel approaches have been investigated such as nanomechanical, electromagnetic, acoustic, molecular, etc. On the other hand, quantum phenomena represent a natural direction for developing nanotechnology, since it has to be considered as a new scale where new phenomena can occur and can be exploited for information purpose...
December 2016: IEEE Transactions on Nanobioscience
Myung Jin Park, Yuna Kim, Youngsoo Kim, Byung Hee Hong
The demands to examine components serving as one of the active layers in heterostructures of 2D materials have been recently increasing. Nanomaterials synthesized from a solution process and their self-assembly can provide a promising route to build a new type of mixed dimensional heterostructures, and several methodologies have been reported previously to construct 2D assemblies from colloidal nanostructures in solution. Graphene quantum dots (GQDs), receiving much interest due to the tunable optical band gap and the capability of chemical functionalization, are considered as emerging nanomaterials for various optoelectronic and biological applications...
January 16, 2017: Small
Marissa A McKercher, Deborah S Wuttke
Heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) experiments offer a rapid and high resolution approach to gaining binding and conformational insights into a protein-peptide interaction. By tracking (1)H and (15)N chemical shift changes over the course of a peptide titration into isotopically labeled protein, amide NH pairs of amino acids whose chemical environment changes upon peptide binding can be identified. When mapped onto a structure of the protein, this approach can identify the peptide-binding interface or regions undergoing conformation changes within a protein upon ligand binding...
2017: Methods in Molecular Biology
Xiangru Wang, Xiaoping Huang, Ziqiang Huang, Liang Wu, Jiyang Shang, Qi Qiu, Shuanghong Wu
We present a scheme of nonmechanical laser beam steering using ZnS/InP quantum dots doping nematic liquid crystal as the optical recording film. Because of its internal electric field generated by blue laser-induced charge carrier distribution, liquid crystal molecules are reoriented to form a phase grating which make the incident angle steer to the angle as we desire. Being a nonmechanical programmable laser beam steering, the anisotropy of the relative permittivity tensor and blue laser-induced electric carriers play a significant effect in determining the reorientable liquid crystal molecule and reconfigurable phase modulation of the gratings, that determines the steering angle and steering efficiency...
December 2017: Nanoscale Research Letters
Yongho Kim, Binh Khanh Mai, Sumin Park
High-valent Cu and Fe species, which are generated from dioxygen activation in metalloenzymes, carry out the functionalization of strong C-H bonds. Understanding the atomic details of the catalytic mechanism has long been one of the main objectives of bioinorganic chemistry. Large H/D kinetic isotope effects (KIEs) were observed in the C-H activation by high-valent non-heme Cu or Fe complexes in enzymes and their synthetic models. The H/D KIE depends significantly on the transition state properties, such as structure, energies, frequencies, and shape of the potential energy surface, when the tunneling effect is large...
January 16, 2017: Journal of Biological Inorganic Chemistry: JBIC
Lin Zhou, Kai Yu, Fan Yang, Jun Zheng, Yuhua Zuo, Chuanbo Li, Buwen Cheng, Qiming Wang
High-performance all-inorganic perovskite-based metal/semiconductor/metal (MSM) photodetectors with a bilayer composite film of mesoporous TiO2 and CsPbBr3 quantum dots as a photosensitizer were prepared. The photodetectors demonstrated significantly improved on/off ratios of nearly three orders of magnitude compared to those of pure bromine-based perovskite nanocrystal photodetectors with an MSM structure.
January 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Wook Lee, Spiridoula Matsika
Cyclobutane pyrimidine dimers (CPDs) are the most commonly formed photochemical products when nucleic acids interact with UV radiation. In duplex DNA, the relative inflexible structure allows for only the cis, syn CPD isomer to be formed. G-quadruplex structures, however, have loops that are more flexible and allow for different orientations of the bases to interact. As a result, the highly unusual formation of an anti CPD has been observed in these structures. Due to the close proximity between two opposing loops containing the TTA sequence in two G-quadruplex structures (called "form-3" and "basket"), a high yield of anti CPD formation was expected in these structures...
January 16, 2017: Physical Chemistry Chemical Physics: PCCP
Clothilde A Eveleens, Alister J Page
Chemical vapour deposition (CVD) growth of carbon nanotubes is currently the most viable method for commercial-scale nanotube production. However, controlling the 'chirality', or helicity, of carbon nanotubes during CVD growth remains a challenge. Recent studies have shown that adding chemical 'etchants', such as ammonia and water, to the feedstock gas can alter the diameter and chirality of nanotubes produced with CVD. To date, this strategy for chirality control remains sub-optimal, since we have a poor understanding of how these etchants change the CVD and nucleation mechanisms...
January 16, 2017: Nanoscale
Michael Kühn, Sergei Lebedkin, Florian Weigend, Andreas Eichhöfer
The optical properties of four isostructural trinuclear chalcogenolato bridged metal complexes [Cu2Sn(SPh)6(PPh3)2], [Cu2Sn(SePh)6(PPh3)2], [Ag2Sn(SPh)6(PPh3)2] and [Cu2Ti(SPh)6(PPh3)2] have been investigated by absorption and photoluminescence spectroscopy and time-dependent density functional theory (TDDFT) calculations. All copper-tin compounds demonstrate near-infrared (NIR) phosphorescence at ∼900-1100 nm in the solid state at low temperature, which is nearly absent at ambient temperature. Stokes shifts of these emissions are found to be unusually large with values of about 1...
January 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Storm E Weiner, Marios C Tsatsos, Lorenz S Cederbaum, Axel U J Lode
Vortices are essential to angular momentum in quantum systems such as ultracold atomic gases. The existence of quantized vorticity in bosonic systems stimulated the development of the Gross-Pitaevskii mean-field approximation. However, the true dynamics of angular momentum in finite, interacting many-body systems like trapped Bose-Einstein condensates is enriched by the emergence of quantum correlations whose description demands more elaborate methods. Herein we theoretically investigate the full many-body dynamics of the acquisition of angular momentum by a gas of ultracold bosons in two dimensions using a standard rotation procedure...
January 16, 2017: Scientific Reports
Sharmistha Karmakar, Ayan Datta
Direct dynamics calculation using canonical variational transtition state theory (CVT) inclusive of small curvature tunneling (SCT) reveals the influential role of quantum mechanical tunneling (QMT) for 2,2a,5,7b-tetrahydro-1H-cyclobuta[e]indene derivatives (2a-2j) in governing their product selectivity. 2a-2j follow two distinct reaction channels namely 6pi-electrocyclization (2-->3) and [1, 5]H-sigmatropic shift (2-->4) amongst which the activation barrier is higher for [1, 5]H-shift (2-->4) thereby favoring the kinetically controlled product (3a-3j) as anticipated...
January 16, 2017: Journal of Organic Chemistry
Anna Ignaczak, Bartłomiej Pałecz, Sylwia Belica-Pacha
β-Cyclodextrin (β-CD) is studied as a carrier of the drug mianserin (MIA). β-CD with MIA adducts with 1 : 1 and 2 : 1 stoichiometry are investigated in vacuo and in water using quantum chemical methods: PM6 and B3LYP/6-31G(d,p). An effect of the dispersion correction GD2 and the basis set superposition error on the complexation energies is also evaluated. Additionally, the interaction between MIA hydrochloride and β-CD in aqueous solution at 298.15 K is examined experimentally by isothermal titration calorimetry...
January 16, 2017: Organic & Biomolecular Chemistry
Chaevien S Clendinen, Gregory S Stupp, Bing Wang, Timothy J Garrett, Arthur S Edison
ABSTRACT BACKGROUND: Isotopic Ratio Outlier Analysis (IROA) is an untargeted metabolomics method that uses stable isotopic labeling and LC-HRMS for identification and relative quantification of metabolites in a biological sample under varying experimental conditions. OBJECTIVE: We demonstrate a method using high-sensitivity (13)C NMR to identify an unknown metabolite isolated from fractionated material from an IROA LC-HRMS experiment. METHODS: IROA samples from the nematode Caenorhabditis elegans were fractionated using LC-HRMS using 5 repeated injections and collecting 30 sec fractions...
August 2016: Current Metabolomics
Sandeep Mavadia, Virginia Frey, Jarrah Sastrawan, Stephen Dona, Michael J Biercuk
The wide-ranging adoption of quantum technologies requires practical, high-performance advances in our ability to maintain quantum coherence while facing the challenge of state collapse under measurement. Here we use techniques from control theory and machine learning to predict the future evolution of a qubit's state; we deploy this information to suppress stochastic, semiclassical decoherence, even when access to measurements is limited. First, we implement a time-division multiplexed approach, interleaving measurement periods with periods of unsupervised but stabilised operation during which qubits are available, for example, in quantum information experiments...
January 16, 2017: Nature Communications
Tian Zhong, Jonathan M Kindem, Jake Rochman, Andrei Faraon
Ensembles of solid-state optical emitters enable broadband quantum storage and transduction of photonic qubits, with applications in high-rate quantum networks for secure communications and interconnecting future quantum computers. To transfer quantum states using ensembles, rephasing techniques are used to mitigate fast decoherence resulting from inhomogeneous broadening, but these techniques generally limit the bandwidth, efficiency and active times of the quantum interface. Here, we use a dense ensemble of neodymium rare-earth ions strongly coupled to a nanophotonic resonator to demonstrate a significant cavity protection effect at the single-photon level-a technique to suppress ensemble decoherence due to inhomogeneous broadening...
January 16, 2017: Nature Communications
Nghia Tuan Duong, Yusuke Nishiyama
Recent study has demonstrated the application of the proton-detected heteronuclear multi-quantum coherence (HMQC) at ultrafast Magic Angle Spinning (MAS) to probe quadrupolar nuclei including (14)N and (35)Cl. In addition, for half-integer quadrupolar nucleus like (35)Cl, the quadrupolar product can be calculated based on the shift difference between the center band of satellite transition (ST) and the central transition (CT) peaks. The applicability of this technique is further investigated on spin I=5/2, namely (27)Al nucleus, and kaolin is chosen as the testing sample...
January 4, 2017: Solid State Nuclear Magnetic Resonance
Noël J Diepens, Evelyne Buffan-Dubau, Hélène Budzinski, Jean Kallerhoff, Georges Merlina, Jérome Silvestre, Isabelle Auby, Nathalie Tapie, Arnaud Elger
Worldwide seagrass declines have been observed due to multiple stressors. One of them is the mixture of pesticides used in intensive agriculture and boat antifouling paints in coastal areas. Effects of mixture toxicity are complex and poorly understood. However, consideration of mixture toxicity is more realistic and ecologically relevant for environmental risk assessment (ERA). The first aim of this study was to determine short-term effects of realistic herbicide mixture exposure on physiological endpoints of Zostera noltei...
January 11, 2017: Environmental Pollution
Charlotte Martineau-Corcos, Jiri Dědeček, Francis Taulelle
In this paper, we review and illustrate applications, reported in the literature or used in our group, of (27)Al-(27)Al double-quantum single-quantum (DQ-SQ) MAS NMR experiments for the structural characterization of Al-containing microporous solids, namely zeolites, aluminophosphates and metal-organic frameworks. Information regarding the periodic frameworks or the localization of the various aluminum species in the materials are obtained from the analysis of the two-dimensional NMR spectra, which allows getting local structural details sometimes inaccessible from other characterization technique...
December 28, 2016: Solid State Nuclear Magnetic Resonance
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