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# Diamond

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#1
Heidi J MacLean, Clint A Penick, Robert R Dunn, Sarah E Diamond
The frequency of warm winter days is increasing under global climate change, but how organisms respond to warmer winters is not well understood. Most studies focus on growing season responses to warming. Locomotor performance is often highly sensitive to temperature, and can determine fitness outcomes through a variety of mechanisms including resource acquisition and predator escape. As a consequence, locomotor performance, and its impacts on fitness, may be strongly affected by winter warming in winter-active species...
May 23, 2017: Journal of Insect Physiology
#2
Jia Zhou, Yujie Liu, Lingyu Huang, Yahang Tan, Xingchen Li, Hong Zhang, Yanhe Ma, Ying Zhang
OBJECTIVE: We sought to compare the performance of the updated Diamond-Forrester method (UDFM), Duke clinical score (DCS), Genders clinical model (GCM) and Genders extended model (GEM) in a Chinese population referred to coronary computed tomography angiography (coronary CTA). BACKGROUND: The reliability of existing models to calculate the pretest proability (PTP) of obstructive coronary artery disease (CAD) have not been fully investigated, especially in a Chinese population...
May 11, 2017: Journal of Cardiovascular Computed Tomography
#3
B A Myers, A Ariyaratne, A C Bleszynski Jayich
We probe the relaxation dynamics of the full three-level spin system of near-surface nitrogen-vacancy (NV) centers in diamond to define a T_{1} relaxation time that sets the T_{2}≤2T_{1} coherence limit of the NV's subset qubit superpositions. We find that double-quantum spin relaxation via electric field noise dominates T_{1} of near-surface NVs at low applied magnetic fields. Furthermore, we differentiate 1/f^{α} spectra of electric and magnetic field noise using a novel noise-spectroscopy technique, with broad applications in probing surface-induced decoherence at material interfaces...
May 12, 2017: Physical Review Letters
#4
Tim Schröder, Matthew E Trusheim, Michael Walsh, Luozhou Li, Jiabao Zheng, Marco Schukraft, Alp Sipahigil, Ruffin E Evans, Denis D Sukachev, Christian T Nguyen, Jose L Pacheco, Ryan M Camacho, Edward S Bielejec, Mikhail D Lukin, Dirk Englund
The controlled creation of defect centre-nanocavity systems is one of the outstanding challenges for efficiently interfacing spin quantum memories with photons for photon-based entanglement operations in a quantum network. Here we demonstrate direct, maskless creation of atom-like single silicon vacancy (SiV) centres in diamond nanostructures via focused ion beam implantation with ∼32 nm lateral precision and <50 nm positioning accuracy relative to a nanocavity. We determine the Si+ ion to SiV centre conversion yield to be ∼2...
May 26, 2017: Nature Communications
#5
J M Boss, K S Cujia, J Zopes, C L Degen
Quantum sensing takes advantage of well-controlled quantum systems for performing measurements with high sensitivity and precision. We have implemented a concept for quantum sensing with arbitrary frequency resolution, independent of the qubit probe and limited only by the stability of an external synchronization clock. Our concept makes use of quantum lock-in detection to continuously probe a signal of interest. Using the electronic spin of a single nitrogen-vacancy center in diamond, we demonstrate detection of oscillating magnetic fields with a frequency resolution of 70 microhertz over a megahertz bandwidth...
May 26, 2017: Science
#6
Simon Schmitt, Tuvia Gefen, Felix M Stürner, Thomas Unden, Gerhard Wolff, Christoph Müller, Jochen Scheuer, Boris Naydenov, Matthew Markham, Sebastien Pezzagna, Jan Meijer, Ilai Schwarz, Martin Plenio, Alex Retzker, Liam P McGuinness, Fedor Jelezko
Precise timekeeping is critical to metrology, forming the basis by which standards of time, length, and fundamental constants are determined. Stable clocks are particularly valuable in spectroscopy because they define the ultimate frequency precision that can be reached. In quantum metrology, the qubit coherence time defines the clock stability, from which the spectral linewidth and frequency precision are determined. We demonstrate a quantum sensing protocol in which the spectral precision goes beyond the sensor coherence time and is limited by the stability of a classical clock...
May 26, 2017: Science
#7
Manon Sorais, Ali Rezaei, Joseph O Okeme, Miriam L Diamond, Ricardo Izquierdo, Jean-François Giroux, Jonathan Verreault
Birds have been used intensively as biomonitors of halogenated flame retardants (HFRs), and several studies have reported elevated tissue concentrations and inter-individual variability for these contaminants. While diet is known to be an important exposure pathway for HFRs in birds, it has been suggested that exposure through air may represent an underestimated source of HFRs for certain species. However, a method was not available for measuring the atmospheric exposure of individual birds to HFRs or other semi-volatile contaminants...
May 21, 2017: Science of the Total Environment
#8
Lee D McDaniel, Karina L Conkrite, Xiao Chang, Mario Capasso, Zalman Vaksman, Derek A Oldridge, Anna Zachariou, Millicent Horn, Maura Diamond, Cuiping Huo, Achille Iolascon, Hakon Hakonarson, Nazneen Rahman, Marcella Devoto, Sharon J Diskin
Neuroblastoma is a cancer of the developing sympathetic nervous system that most commonly presents in young children and accounts for approximately 12% of pediatric oncology deaths. Here, we report on a genome-wide association study (GWAS) in a discovery cohort or 2,101 cases and 4,202 controls of European ancestry. We identify two new association signals at 3q25 and 4p16 that replicated robustly in multiple independent cohorts comprising 1,163 cases and 4,396 controls (3q25: rs6441201 combined P = 1.2x10-11, Odds Ratio 1...
May 18, 2017: PLoS Genetics
#9
Taras Leonidovych Petrenko, V Bryksa
At present nitrogen-vacancy (NV) complex in diamond is the most promising defect for application in the area of quantum computing. This provides a stimulus for extensive search of another defects in semiconductors with similar properties. Recently it was shown that N$_{C}$V$_{Si}$ defect complex in SiC is perspective for this goal as well. In the present work we perform comparative \textit{ab initio} studies of NV complexes in diamond and 3\textit{C}-SiC. We focus both on radiospectroscopic characterization of these defects and on calculation of equilibrium concentration of complexes in irradiated crystals...
May 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
#10
Sarah E Diamond, Lacy Chick, Clint A Penick, Lauren M Nichols, Sara Helms Cahan, Robert R Dunn, Aaron M Ellison, Nathan J Sanders, Nicholas J Gotelli
Few studies have quantified the relative importance of direct effects of climate change on communities versus indirect effects that are mediated thorough species interactions, and the limited evidence is conflicting. Trait-based approaches have been popular in studies of climate change, but can they be used to estimate direct versus indirect effects? At the species level, thermal tolerance is a trait that is often used to predict winners and losers under scenarios of climate change. But thermal tolerance might also inform when species interactions are likely to be important because only subsets of species will be able to exploit the available warmer climatic niche space, and competition may intensify in the remaining, compressed cooler climatic niche space...
May 24, 2017: Integrative and Comparative Biology
#11
Dominic Montagu, May Sudhinaraset, Nadia Diamond-Smith, Oona Campbell, Sabine Gabrysch, Lynn Freedman, Margaret E Kruk, France Donnay
Growing evidence from a number of countries in Asia and Africa documents a large shift towards facility deliveries in the past decade. These increases have not led to the improvements in health outcomes that were predicted by health policy researchers in the past. In light of this unexpected evidence, we have assessed data from multiple sources, including nationally representative data from 43 countries in Asia and Africa, to understand the size and range of changing delivery location in Asia and Africa. We have reviewed the policies, programs and financing experiences in multiple countries to understand the drivers of changing practices, and the consequences for maternal and neonatal health and the health systems serving women and newborns...
May 25, 2017: Health Policy and Planning
#12
Maira Possas-Abreu, Farbod Ghassemi, Lionel Rousseau, Emmanuel Scorsone, Emilie Descours, Gaelle Lissorgues
This paper reports on the development of an autonomous instrument based on an array of eight resonant microcantilevers for vapor detection. The fabricated sensors are label-free devices, allowing chemical and biological functionalization. In this work, sensors based on an array of silicon and synthetic diamond microcantilevers are sensitized with polymeric films for the detection of analytes. The main advantage of the proposed system is that sensors can be easily changed for another application or for cleaning since the developed gas cell presents removable electrical connections...
May 24, 2017: Sensors
#13
Justin T Jasper, Yang Yang, Michael R Hoffmann
Electrochemical systems are an attractive option for onsite latrine wastewater treatment due to their high efficiency and small footprint. While concerns remain over formation of toxic byproducts during treatment, rigorous studies examining byproduct formation are lacking. Experiments treating authentic latrine wastewater over variable treatment times, current densities, chloride concentrations, and anode materials were conducted to characterize byproducts and identify conditions that minimize their formation...
May 24, 2017: Environmental Science & Technology
#14
Hua Lin, Hong Chen, Yu-Jun Zheng, Ju-Song Yu, Xin-Tao Wu, Li-Ming Wu
Mid- and far-infrared (MFIR) nonlinear optical (NLO) crystals with excellent performances are critical to laser frequency-conversion technology. However, the current commercial MFIR NLO crystals, including AgGaS2 (AGS), AgGaSe2 and ZnGeP2, suffer from certain intrinsic drawbacks and cannot achieve a good balance between large second-harmonic generation (SHG) efficiency and high laser-induced damage thresholds (LIDTs). Herein, we report two new phase-matchable MFIR NLO chalcogenides, specifically RbXSn2Se6 (X = Ga, In), which were successfully synthesized by high-temperature solid-state reactions...
May 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
#15
Zhenhai Yu, Wei Wu, Pengchao Lu, Jinggeng Zhao, Jinguang Cheng, Qingyang Hu, Ye Yuan, Xin Li, Cuiying Pei, Fengjiao Chen, Zhipeng Yan, Shuai Yan, Ke Yang, Jian Sun, Jianlin Luo, Lin Wang
The influence of external pressure on the structural properties of manganese monophosphides (MnP) at room temperature has been studied using in situ angle dispersive synchrotron x-ray powder diffraction (AD-XRD) with a diamond anvil cell. The crystal structure of MnP is stable between 0 to 15 GPa. However, the compressibility of b-axis is much larger than those of a- and c-axes. From this result we suggested that the occurrence of superconductivity in MnP was induced by suppression of the long-range antiferromagnetically ordered state rather than a structural phase transition...
May 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
#16
Martin Hetzl, Max Kraut, Theresa Hoffmann, Martin Stutzmann
Group III-nitride materials such as GaN nanowires are characterized by a spontaneous polarization within the crystal. The sign of the resulting sheet charge at the top and bottom facet of a GaN nanowire is determined by the orientation of the wurtzite bilayer of the different atomic species, called N and Ga polarity. We investigate the polarity distribution of heteroepitaxial GaN nanowires on different substrates and demonstrate polarity control of GaN nanowires on diamond. Kelvin Probe Force Microscopy is used to determine the polarity of individual selective area-grown and self-assembled nanowires over a large scale...
May 23, 2017: Nano Letters
#17
Naoki Sakashita, Hiroshi C Watanabe, Takuya Ikeda, Keisuke Saito, Hiroshi Ishikita
The cyanobacterial photosystem II (PSII) crystal structure includes more than 1300 water molecules in each monomer unit; however, their precise roles in water oxidation are unclear. To understand the origins of water molecules in the PSII crystal structure, the accessibility of bulk water molecules to channel inner spaces in PSII was investigated using the water-removed PSII structure and molecular dynamics (MD) simulations. The inner space of the channel that proceeds toward the D1-Glu65/D2-Glu312 pair (E65/E312 channel) was entirely filled with water molecules from the bulk region...
May 23, 2017: Biochemistry
#18
Simone Salustro, Giuseppe Sansone, Claudio M Zicovich-Wilson, Yves Noël, Lorenzo Maschio, Roberto Dovesi
The A-center in diamond, which consists of two nitrogen atoms substituting two neighboring carbon atoms, has been investigated at the quantum mechanical level using an all-electron Gaussian type basis set, hybrid functionals and the periodic supercell approach. In order to simulate different defect concentrations, four supercells have been considered containing 32, 64, 128 and 216 atoms, respectively. The ground state is a closed shell system where the two neighboring nitrogen atoms are separated, as a consequence of the strong repulsive interaction between the lone pairs, by 2...
May 23, 2017: Physical Chemistry Chemical Physics: PCCP
#19
Kyoung-Tak Kang, Juhyun Son, Ho-Joong Kim, Changhyun Baek, Oh-Ryong Kwon, Yong-Gon Koh
The wear of ultrahigh-molecular weight polyethylene (UHMWPE) tibial inserts in total knee arthroplasty (TKA) remains a major limitation that hinders the longevity of clinically successful devices. Surface properties significantly affect the overall performance of TKA, and surface modification with mechanically and chemically stable materials is an effective method for overcoming the wear of TKA. However, wear tests are not cost-efficient or time-efficient; thus, the effects of geometric, loading, and alignment perturbations are often evaluated via parametric studies...
July 2017: Journal of Materials Science. Materials in Medicine
#20
Dylan R Rittman, Katlyn M Turner, Sulgiye Park, Antonio F Fuentes, Changyong Park, Rodney C Ewing, Wendy L Mao
Strain engineering is a promising method for next-generation materials processing techniques. Here, we use mechanical milling and annealing followed by compression in diamond anvil cell to tailor the intrinsic and extrinsic strain in pyrochlore, Dy2Ti2O7 and Dy2Zr2O7. Raman spectroscopy, X-ray pair distribution function analysis, and X-ray diffraction were used to characterize atomic order over short-, medium-, and long-range spatial scales, respectively, under ambient conditions. Raman spectroscopy and X-ray diffraction were further employed to interrogate the material in situ at high pressure...
May 22, 2017: Scientific Reports
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