bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal structure of the homocysteine methyltransferase MmuM from Escherichia coli
Authors: Li Kunhua , Li Gengnan , Bradbury Louis M.T. , Hanson Andrew D. , Bruner Steven D.
Published: November 2015

Homocysteine S-methyltransferases (HMTs, EC 2.1.1.0) catalyse the conversion of homocysteine to methionine using S-methylmethionine or S-adenosylmethionine as the methyl donor. HMTs play an important role in methionine biosynthesis and are widely distributed among micro-organisms, plants and animals. Additionally, HMTs play a role in metabolite repair of S-adenosylmethionine by removing an inactive diastereomer from the pool. The mmuM gene product from Escherichia coli is an archetypal HMT family protein and contains a predicted zinc-binding motif in the enzyme active site. In the present study, we demonstrate X-ray structures for MmuM in oxidized, apo and metallated forms, representing the first such structures for any member of the HMT family. The structures reveal a metal/substrate-binding pocket distinct from those in related enzymes. The presented structure analysis and modelling of co-substrate interactions provide valuable insight into the function of MmuM in both methionine biosynthesis and cofactor repair.
Front‐to‐back ratio improvement of a short pyramidal horn antenna using metal strips/rods in LTE/cellular band
Authors: Lee Kyoung‐Joo , Oh Soon‐Soo , Lee Young‐Hwan , Kim Young‐Sik
Published: November 2015

This study presents a very short pyramidal horn antenna for monitoring the radiation characteristics of mobile base‐station (BS) antennas operating in the long‐term evolution (LTE)/cellular band. The proposed short pyramidal horn is integrated with metal strips/rods to overcome deficiencies of the shortened horn, especially in its front‐to‐back (F/B) ratio. The proposed short horn antenna improves the average F/B ratio by at least 8 dB in the frequency range from 690–960 MHz by controlling the edge diffraction. The total length of the antenna, including a waveguide flange, is only approximately 0.6 λ at 800 MHz. The proposed antenna also retains good characteristics such as a monotonically increasing gain, wide bandwidth, and a good purity of polarisation. The proposed antenna can replace the dipole antenna as a reference gain antenna for both indoor and outdoor measurement systems below the L‐band.
Raman radial breathing mode frequency of boron nitride nanotubes with bounded uncertain material properties
Authors: Ghavanloo Esmaeal , Fazelzadeh S. Ahmad
Published: November 2015

This Letter presents an analytical formulation for predicting the radial breathing mode (RBM) frequency of boron nitride nanotubes (BNNTs) with arbitrary chirality. Accurate material properties of the BNNTs are usually not available and the values of the material properties have certain amount of scatter, and some level of uncertainty. In the present investigation, the convex modelling is utilised to consider the bounded uncertain material properties in calculating the RBM frequency of the BNNTs. The results are compared with available data in the literature. Present study may provide useful information on the RBM frequency of the BNNTs with arbitrary chirality in practical applications.
Nanoparticulated hydrophobic CdO coatings deposited by microwave procedure
Authors: Rashidzadeh Mehrdad , Carbajal‐Franco Guillermo , Tiburcio‐Silver Arturo
Published: November 2015

A novel and inexpensive way to deposit nanostructured cadmium oxide (CdO) coatings is described. Metallic Cd is evaporated by heating a silicon carbide crucible, via microwave radiation at standard atmosphere conditions. The Cd vapour rises from the crucible and reacts with the atmospheric oxygen depositing on a glass substrate. CdO coating is homogeneously distributed above the glass surface and it presents a well‐defined cubic‐shaped nanostructure. The as‐deposited CdO coatings showed good hydrophobic properties and achieved symmetric contact angles of 112°. The hydrophobic behaviour was lost after a 75 min of heat treatment at 723 K.
Numerical simulations of the first operational conditions of the negative ion test facility SPIDER
Authors: Serianni G. , Agostinetti P. , Antoni V. , Baltador C. , Cavenago M. , Chitarin G. , Marconato N. , Pasqualotto R. , Sartori E. , Toigo V. , Veltri P.
Published: November 2015

In view of the realization of the negative ion beam injectors for ITER, a test facility, named SPIDER, is under construction in Padova (Italy) to study and optimize production and extraction of negative ions. The present paper is devoted to the analysis of the expected first operations of SPIDER in terms of single-beamlet and multiple-beamlet simulations of the hydrogen beam optics in various operational conditions. The effectiveness of the methods adopted to compensate for the magnetic deflection of the particles is also assessed. Indications for a sequence of the experimental activities are obtained.
A molecular dynamics simulation of the turbulent Couette minimal flow unit
Authors: Smith E. R.
Published: November 2015

A molecular dynamics simulation of planar Couette flow is presented for the minimal channel in which turbulence structures can be sustained. Evolution over a single breakdown and regeneration cycle is compared to computational fluid dynamics simulations. Qualitative similar structures are observed and turbulent statistics show excellent quantitative agreement. The molecular scale law of the wall is presented in which stick-slip molecular wall-fluid interactions replace the no-slip conditions. The impact of grid resolution is explored and the observed structures are seen to be dependent on averaging time and length scales. The kinetic energy spectra show that a range of scales are present in the molecular system and that spectral content is dependent on the grid resolution employed. The subgrid velocity of the molecules is studied using joint probability density functions, molecular trajectories, diffusion, and Lagrangian statistics. The importance of sub-grid scales, relevance of the Kolmogorov lengthscale, and implications of molecular turbulence are discussed.
Charge breeder for the SPIRAL1 upgrade: Preliminary results
Authors: Maunoury L. , Delahaye P. , Dubois M. , Angot J. , Sole P. , Bajeat O. , Barton C. , Frigot R. , Jeanne A. , Jardin P. , Kamalou O. , Lecomte P. , Osmond B. , Peschard G. , Lamy T. , Savalle A.
Published: November 2015

In the framework of the SPIRAL1 upgrade under progress at the GANIL lab, the charge breeder based on a LPSC Phoenix ECRIS, first tested at ISOLDE has been modified to benefit of the last enhancements of this device from the 1+/n+ community. The modifications mainly concern the 1 + optics, vacuum techniques, and the RF—buffer gas injection into the charge breeder. Prior to its installation in the midst of the low energy beam line of the SPIRAL1 facility, it has been decided to qualify its performances and several operation modes at the test bench of LPSC lab. This contribution shall present preliminary results of experiments conducted at LPSC concerning the 1 + to n+ conversion efficiencies for noble gases as well as for alkali elements and the corresponding transformation times.
Real-time observation of coherent acoustic phonons generated by an acoustically mismatched optoacoustic transducer using x-ray diffraction
Authors: Persson A. I. H. , Enquist H. , Jurgilaitis A. , Andreasson B. P. , Larsson J.
Published: November 2015

The spectrum of laser-generated acoustic phonons in indium antimonide coated with a thin nickel film has been studied using time-resolved x-ray diffraction. Strain pulses that can be considered to be built up from coherent phonons were generated in the nickel film by absorption of short laser pulses. Acoustic reflections at the Ni–InSb interface leads to interference that strongly modifies the resulting phonon spectrum. The study was performed with high momentum transfer resolution together with high time resolution. This was achieved by using a third-generation synchrotron radiation source that provided a high-brightness beam and an ultrafast x-ray streak camera to obtain a temporal resolution of 10 ps. We also carried out simulations, using commercial finite element software packages and on-line dynamic diffraction tools. Using these tools, it is possible to calculate the time-resolved x-ray reflectivity from these complicated strain shapes. The acoustic pulses have a peak strain amplitude close to 1%, and we investigated the possibility to use this device as an x-ray switch. At a bright source optimized for hard x-ray generation, the low reflectivity may be an acceptable trade-off to obtain a pulse duration that is more than an order of magnitude shorter.
Wideband fluorescence-based thermometry by neural network recognition: Photothermal application with 10 ns time resolution
Authors: Liu Liwang , Zhong Kuo , Munro Troy , Alvarado Salvador , Côte Renaud , Creten Sebastiaan , Fron Eduard , Ban Heng , Van der Auweraer Mark , Roozen N. B. , Matsuda Osamu , Glorieux Christ
Published: November 2015

Neural network recognition of features of the fluorescence spectrum of a thermosensitive probe is exploited in order to achieve fluorescence-based thermometry with an accuracy of 200 mK with 100 MHz bandwidth, and with high robustness against fluctuations of the probe laser intensity used. The concept is implemented on a rhodamine B dyed mixture of copper chloride and glycerol, and the temperature dependent fluorescence is investigated in the temperature range between 234 K and 311 K. The spatial dependence of the calibrated amplitude and phase of photothermally induced temperature oscillations along the axis of the excitation laser are determined at different modulation frequencies. The spatial and frequency dependence of the extracted temperature signals is well fitted by a 1D multi-layer thermal diffusion model. In a time domain implementation of the approach, the gradual temperature rise due to the accumulation of the DC component of the heat flux supplied by repetitive laser pulses as well the immediate transient temperature evolution after each single pulse is extracted from acquired temporal sequences of fluorescence spectra induced by a CW green laser. A stroboscopic implementation of fluorescence thermometry, using a pulsed fluorescence evoking probe laser, is shown to achieve remote detection of temperature changes with a time resolution of 10 ns.
Algorithms for SU(n) boson realizations and D-functions
Authors: Dhand Ish , Sanders Barry C. , de Guise Hubert
Published: November 2015

Boson realizations map operators and states of groups to transformations and states of bosonic systems. We devise a graph-theoretic algorithm to construct the boson realizations of the canonical SU(n) basis states, which reduce the canonical subgroup chain, for arbitrary n. The boson realizations are employed to construct D-functions, which are the matrix elements of arbitrary irreducible representations, of SU(n) in the canonical basis. We demonstrate that our D-function algorithm offers significant advantage over the two competing procedures, namely, factorization and exponentiation.
Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms
Authors: Pruttivarasin Thaned , Katori Hidetoshi
Published: November 2015

We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.
Determination of the blocking temperature of magnetic nanoparticles: The good, the bad, and the ugly
Authors: Bruvera I. J. , Mendoza Zélis P. , Pilar Calatayud M. , Goya G. F. , Sánchez F. H.
Published: November 2015

A numerically solved two-level Stoner-Wohlfarth model with thermal agitation is used to simulate Zero Field Cooling (ZFC)–Field Cooling (FC) curves of monosize and polysize samples and to determine the best method for obtaining a representative blocking temperature TB value of polysize samples. The results confirm a technique based on the T derivative of the difference between ZFC and FC curves proposed by Micha et al. (the good) and demonstrate its relation with two alternative methods: the ZFC maximum (the bad) and the inflection point (the ugly). The derivative method is then applied to experimental data, obtaining the TB distribution of a polysize Fe3O4 nanoparticle sample suspended in hexane with an excellent agreement with TEM characterization.
Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism
Authors: Li Zhen , Bian Xin , Li Xiantao , Karniadakis George Em
Published: November 2015

The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.
Theoretical spectroscopy study of the low-lying electronic states of UX and UX+, X = F and Cl
Authors: Bross David H. , Peterson Kirk A.
Published: November 2015

Spectroscopic constants (Te, re, B0, ωe, and ωexe) have been calculated for the low-lying electronic states of UF, UF+, UCl, and UCl+ using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess Hamiltonians for the U atom. Spin orbit (SO) effects were included a posteriori using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component methods for U+ and UF+. Complete basis set (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω = 9/2 ground states. The first excited state of UCl was calculated to be an Ω = 7/2 state at 78 cm−1 as opposed to the same state at 435 cm−1 in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise, UF+ and UCl+ both have Ω = 4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states was energetically closer together in UCl+ than in UF+, ranging up to 776 cm−1 in UF+ and only 438 cm−1 in UCl+. As in previous studies, the final PP-based SO-CASPT2 results for UF+ and UF agree well with experiment and are expected to be predictive for UCl and UCl+, which are reported here for the first time.
On jet impingement and thin film breakup on a horizontal superhydrophobic surface
Authors: Prince Joseph F. , Maynes Daniel , Crockett Julie
Published: November 2015

When a vertical laminar jet impinges on a horizontal surface, it will spread out in a thin film. If the surface is hydrophobic and a downstream depth is not maintained, the film will radially expand until it breaks up into filaments or droplets. We present the first analysis and model that describes the location of this transition for both isotropic and anisotropic structured superhydrophobic (SH) surfaces. All surfaces explored are hydrophobic or SH, where the SH surfaces exhibit an apparent slip at the plane of the surface due to a shear free condition above the air filled cavities between the structures. The influence of apparent slip on the entire flow field is significant and yields behavior that deviates notably from classical behavior for a smooth hydrophilic surface where a hydraulic jump would form. Instead, break up into droplets occurs where the jet’s outward radial momentum is balanced by the inward surface tension force of the advancing film. For hydrophobic surfaces, or SH surfaces with random micropatterning, the apparent slip on the surface is uniform in all directions and droplet breakup occurs in a circular pattern. When alternating rib/cavity microstructures are used to create the SH surface, the apparent slip varies as a function of the azimuthal coordinate, and thus, the breakup location is elliptically shaped. The thin film dynamics are modeled by a radial momentum analysis for a given jet Weber number and specified slip length and the location of breakup for multiple surfaces over a range of jet Weber numbers and realistic slip length values is quantified. The results of the analysis show that the breakup radius increases with increasing Weber number and slip length. The eccentricity of the breakup ellipse for the rib/cavity SH structures increases with increasing Weber number and slip length as well. A generalized model that allows prediction of the transition (break-up) location as a function of all influencing parameters is presented. Model results are compared to experimental measurements with very good agreement.
Eigenvalues of the string constraints for the Kadomtsev-Petviashvili hierarchy
Authors: Liu Shaowei
Published: November 2015

For an arbitrary p ∈ ℕ, a new and computable method is proposed, which can, through a recursive algorithm, calculate the eigenvalues of the string constraint operators corresponding to the τ-function of the p-reduced Kadomtsev-Petviashvili (KP) hierarchy. It shows that not all of these eigenvalues equal 0. In this process, a connection between the W algebra and the p-reduced W algebra is introduced, which can be used to calculate the algebraic structure of the p-reduced W algebra. And it is proved that the p-reduced W algebra includes a Virasoro algebra as its subalgebra. In addition, based on the obtained eigenvalues, it is also showed that the τ-function of the p-reduced KP hierarchy constrained by the string equation is a vacuum vector for a Virasoro algebra for any p ∈ ℕ. When p = 2, it is coincident with the classical fact that the τ-function of the Korteweg-de Vries hierarchy constrained by the string equation is a vacuum vector for a Virasoro algebra.
Sub-10 nm nanopantography
Authors: Tian Siyuan , Donnelly Vincent M. , Ruchhoeft Paul , Economou Demetre J.
Published: November 2015

Nanopantography, a massively parallel nanopatterning method over large areas, was previously shown to be capable of printing 10 nm features in silicon, using an array of 1000 nm-diameter electrostatic lenses, fabricated on the substrate, to focus beamlets of a broad area ion beam on selected regions of the substrate. In the present study, using lens dimensional scaling optimized by computer simulation, and reduction in the ion beam image size and energy dispersion, the resolution of nanopantography was dramatically improved, allowing features as small as 3 nm to be etched into Si.
A network of discrete events for the representation and analysis of diffusion dynamics
Authors: Pintus Alberto M. , Pazzona Federico G. , Demontis Pierfranco , Suffritti Giuseppe B.
Published: November 2015

We developed a coarse-grained description of the phenomenology of diffusive processes, in terms of a space of discrete events and its representation as a network. Once a proper classification of the discrete events underlying the diffusive process is carried out, their transition matrix is calculated on the basis of molecular dynamics data. This matrix can be represented as a directed, weighted network where nodes represent discrete events, and the weight of edges is given by the probability that one follows the other. The structure of this network reflects dynamical properties of the process of interest in such features as its modularity and the entropy rate of nodes. As an example of the applicability of this conceptual framework, we discuss here the physics of diffusion of small non-polar molecules in a microporous material, in terms of the structure of the corresponding network of events, and explain on this basis the diffusivity trends observed. A quantitative account of these trends is obtained by considering the contribution of the various events to the displacement autocorrelation function.
Characterization method of hydrophobic anti-icing coatings
Authors: Morita Katsuaki , Sakaue Hirotaka
Published: November 2015

For anti-icing, supercooled water should be removed before frozen onto the contact surface. We use a hydrophobic coating for anti-icing and introduce the static- and dynamic-evaluation methods. The methods describe the contact surface between the hydrophobic surface and a supercooled-water droplet. The former is based on the contact angle, and the latter is based on the sliding angle. The temperature factor is included in these models to evaluate the hydrophobic coating under the supercooled conditions. Four hydrophobic coatings are experimentally evaluated based on the static- and dynamic evaluation methods: C1–C3 (commercial fluorocarbon coatings), and Jaxa coating (original fluorocarbon coating). These are evaluated under the supercooled conditions of −10 to 0 °C. The static-evaluation shows variations in the temperature. However, change in the contact angle by the temperature is relatively small compared to that of the sliding angle for the dynamic evaluation. Only C3 and Jaxa coatings are tolerant to the sliding angle under the supercooled conditions tested. The dynamic evaluation shows that even if the coating is hydrophobic, the dynamic evaluation should be included to understand the characteristic of removal for a supercooled-water droplet.
Dancing the tight rope on the nanoscale—Calibrating a heat flux sensor of a scanning thermal microscope
Authors: Kloppstech K. , Könne N. , Worbes L. , Hellmann D. , Kittel A.
Published: November 2015

We report on a precise in situ procedure to calibrate the heat flux sensor of a near-field scanning thermal microscope. This sensitive thermal measurement is based on 1ω modulation technique and utilizes a hot wire method to build an accessible and controllable heat reservoir. This reservoir is coupled thermally by near-field interactions to our probe. Thus, the sensor’s conversion relation Vth(QGS∗) can be precisely determined. Vth is the thermopower generated in the sensor’s coaxial thermocouple and QGS∗ is the thermal flux from reservoir through the sensor. We analyze our method with Gaussian error calculus with an error estimate on all involved quantities. The overall relative uncertainty of the calibration procedure is evaluated to be about 8% for the measured conversion constant, i.e., (2.40 ± 0.19) μV/μW. Furthermore, we determine the sensor’s thermal resistance to be about 0.21 K/μW and find the thermal resistance of the near-field mediated coupling at a distance between calibration standard and sensor of about 250 pm to be 53 K/μW.
Experimental observation of sub-terahertz backward-wave amplification in a multi-level microfabricated slow-wave circuit
Authors: Baik Chan-Wook , Ahn Ho Young , Kim Yongsung , Lee Jooho , Hong Seogwoo , Lee Sang Hun , Choi Jun Hee , Kim Sunil , Jeon So-Yeon , Yu SeGi , Collins George , Read Michael E. , Lawrence Ives R. , Kim Jong Min , Hwang Sungwoo
Published: November 2015

In our earlier paper dealing with dispersion retrieval from ultra-deep, reactive-ion-etched, slow-wave circuits on silicon substrates, it was proposed that splitting high-aspect-ratio circuits into multilevels enabled precise characterization in sub-terahertz frequency regime. This achievement prompted us to investigate beam-wave interaction through a vacuum-sealed integration with a 15-kV, 85-mA, thermionic, electron gun. Our experimental study demonstrates sub-terahertz, backward-wave amplification driven by an external oscillator. The measured output shows a frequency downshift, as well as power amplification, from beam loading even with low beam perveance. This offers a promising opportunity for the development of terahertz radiation sources, based on silicon technologies.
Electronic properties of Mn-phthalocyanine–C60 bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy
Authors: Roth Friedrich , Herzig Melanie , Lupulescu Cosmin , Darlatt Erik , Gottwald Alexander , Knupfer Martin , Eberhardt Wolfgang
Published: November 2015

The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C60 (MnPc:C60) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C60. Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C60 bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C60 to MnPc thin films.
Photoluminescence studies of polycrystalline Cu(In,Ga)Se2: Lateral inhomogeneities beyond Abbe's diffraction limit
Authors: Neumann Oliver , Brüggemann Rudolf , Hariskos Dimitrios , Witte Wolfram , Bauer Gottfried H.
Published: November 2015

We analyze Cu(In,Ga)Se2 absorbers with a scanning near-field optical microscope (SNOM) by photoluminescence (PL). Such measurements allow one to extract local fluctuations of the integral PL yield, the quasi-Fermi level splitting, and the material composition in the submicron range. However, the experimental findings depend strongly on the surface roughness of the absorber: If the surface is rough, artifact-prone correlations between surface contour and PL features measured by SNOM can be found that complicate the study of recombination effects. For smooth surfaces, such correlations no longer exist and the influence of grain boundaries on the integral PL yield and the quasi-Fermi level splitting is revealed. The method also allows a detailed determination of the local band gaps in neighboring grains and their spatial variation inside, and thus of possibly local changes in chemical composition of different grains.
High quality factor indium oxide mechanical microresonators
Authors: Bartolomé Javier , Cremades Ana , Piqueras Javier
Published: November 2015

The mechanical resonance behavior of as-grown In2O3 microrods has been studied in this work by in-situ scanning electron microscopy (SEM) electrically induced mechanical oscillations. Indium oxide microrods grown by a vapor–solid method are naturally clamped to an aluminum oxide ceramic substrate, showing a high quality factor due to reduced energy losses during mechanical vibrations. Quality factors of more than 105 and minimum detectable forces of the order of 10−16 N/Hz1/2 demonstrate their potential as mechanical microresonators for real applications. Measurements at low-vacuum using the SEM environmental operation mode were performed to study the effect of extrinsic damping on the resonators behavior. The damping coefficient has been determined as a function of pressure.
Quantifying selective alignment of ensemble nitrogen-vacancy centers in (111) diamond
Authors: Tahara Kosuke , Ozawa Hayato , Iwasaki Takayuki , Mizuochi Norikazu , Hatano Mutsuko
Published: November 2015

Selective alignment of nitrogen-vacancy (NV) centers in diamond is an important technique towards its applications. Quantification of the alignment ratio is necessary to design the optimized diamond samples. However, this is not a straightforward problem for dense ensemble of the NV centers. We estimate the alignment ratio of ensemble NV centers along the [111] direction in (111) diamond by optically detected magnetic resonance measurements. Diamond films deposited by N2 doped chemical vapor deposition have NV center densities over 1 × 1015 cm−3 and alignment ratios over 75%. Although spin coherence time (T2) is limited to a few μs by electron spins of nitrogen impurities, the combination of the selective alignment and the high density can be a possible way to optimize NV-containing diamond samples for the sensing applications.
Communication: X-ray absorption spectra and core-ionization potentials within a core-valence separated coupled cluster framework
Authors: Coriani Sonia , Koch Henrik
Published: November 2015

We present a simple scheme to compute X-ray absorption spectra (e.g., near-edge absorption fine structure) and core ionisation energies within coupled cluster linear response theory. The approach exploits the so-called core-valence separation to effectively reduce the excitation space to processes involving at least one core orbital, and it can be easily implemented within any pre-existing coupled cluster code for low energy states. We further develop a perturbation correction that incorporates the effect of the excluded part of the excitation space. The correction is shown to be highly accurate. Test results are presented for a set of molecular systems for which well converged results in full space could be generated at the coupled cluster singles and doubles level of theory only, but the scheme is straightforwardly generalizable to all members of the coupled cluster hierarchy of approximations, including CC3.
Nano-optomechanical nonlinear dielectric metamaterials
Authors: Karvounis Artemios , Ou Jun-Yu , Wu Weiping , MacDonald Kevin F. , Zheludev Nikolay I.
Published: November 2015

By harnessing the resonant nature of localized electromagnetic modes in a nanostructured silicon membrane, an all-dielectric metamaterial can act as nonlinear medium at optical telecommunications wavelengths. We show that such metamaterials provide extremely large optomechanical nonlinearities, operating at intensities of only a few μW per unit cell and modulation frequencies as high as 152 MHz, thereby offering a path to fast, compact, and energy efficient all-optical metadevices.
Coercivity enhancement in Mn-Al-Cu flakes produced by surfactant-assisted milling
Authors: Saravanan P. , Hsu Jen-Hwa , Vinod V. T. P. , Černík Miroslav , Kamat S. V.
Published: November 2015

We herein report the achievement of exceptionally high coercivity (Hc) values: 9.92 and 5.86 kOe at 5 and 300 K, respectively, for Mn55Al43Cu2 flakes produced by surfactant-assisted milling process without employing any heat-treatment. The use of surfactants such as oleic acid and oleylamine during milling yielded high-aspect ratio flakes for the Mn-Al-Cu alloy. Structural studies confirmed the presence of τ- and β-phases as the major constituents in the Mn-Al-Cu flakes. The observed Hc enhancement is due to the increase in anisotropy field and structural defects, which is hypothesized to originate from the domain-wall pinning as a consequence of precipitation of fine Cu-particles present at the grain boundaries.
Communication: Fragment-based Hamiltonian model of electronic charge-excitation gaps and gap closure
Authors: Valone S. M. , Pilania G. , Liu X. Y. , Allen J. R. , Wu T.-C. , Atlas S. R. , Dunlap D. H.
Published: November 2015

Capturing key electronic properties such as charge excitation gaps within models at or above the atomic scale presents an ongoing challenge to understanding molecular, nanoscale, and condensed phase systems. One strategy is to describe the system in terms of properties of interacting material fragments, but it is unclear how to accomplish this for charge-excitation and charge-transfer phenomena. Hamiltonian models such as the Hubbard model provide formal frameworks for analyzing gap properties but are couched purely in terms of states of electrons, rather than the states of the fragments at the scale of interest. The recently introduced Fragment Hamiltonian (FH) model uses fragments in different charge states as its building blocks, enabling a uniform, quantum-mechanical treatment that captures the charge-excitation gap. These gaps are preserved in terms of inter-fragment charge-transfer hopping integrals T and on-fragment parameters U(FH). The FH model generalizes the standard Hubbard model (a single intra-band hopping integral t and on-site repulsion U) from quantum states for electrons to quantum states for fragments. We demonstrate that even for simple two-fragment and multi-fragment systems, gap closure is enabled once T exceeds the threshold set by U(FH), thus providing new insight into the nature of metal-insulator transitions. This result is in contrast to the standard Hubbard model for 1d rings, for which Lieb and Wu proved that gap closure was impossible, regardless of the choices for t and U.
Communication: Dynamical density functional theory for dense suspensions of colloidal hard spheres
Authors: Stopper Daniel , Roth Roland , Hansen-Goos Hendrik
Published: November 2015

We study structural relaxation of colloidal hard spheres undergoing Brownian motion using dynamical density functional theory. Contrary to the partial linearization route [D. Stopper et al., Phys. Rev. E 92, 022151 (2015)] which amounts to using different free energy functionals for the self and distinct part of the van Hove function G(r, t), we put forward a unified description employing a single functional for both components. To this end, interactions within the self part are removed via the zero-dimensional limit of the functional with a quenched self component. In addition, we make use of a theoretical result for the long-time mobility in hard-sphere suspensions, which we adapt to the inhomogeneous fluid. Our results for G(r, t) are in excellent agreement with numerical simulations even in the dense liquid phase. In particular, our theory accurately yields the crossover from free diffusion at short times to the slower long-time diffusion in a crowded environment.
A model for temperature dependent resistivity of metallic superlattices
Authors: Uba J. I. , Ekpunobi A. J. , Ekwo P. I.
Published: November 2015

The temperature dependent resistivity of metallic superlattices, to first order approximation, is assumed to have same form as bulk metal, ρ(T) = ρo + aT, which permits describing these structures as linear atomic chain. The assumption is, substantiated with the derivation of the above expression from the standard magnetoresistance equation, in which the second term, a Bragg scattering factor, is a correction to the usual model involving magnon and phonon scatterings. Fitting the model to Fe/Cr data from literature shows that Bragg scattering is dominant at T < 50 K and magnon and phonon coefficients are independent of experiment conditions, with typical values of 4.7 × 10−4 μΩcmK−2 and −8 ± 0.7 × 10−7μΩcmK−3. From the linear atomic chain model, the dielectric constant εq,ω=8.33×10−2 at Debye frequency for all materials and acoustic speed and Thomas – Fermi screening length are pressure dependent with typical values of 1.53 × 104 m/s and 1.80 × 109 m at 0.5 GPa pressure for an Fe/Cr structure.
Synthesis and Biological Screening of Silicon-Containing Ibuprofen Derivatives: A Study of Their NF-κβ Inhibitory Activity, Cytotoxicity, and Their Ability to Bind IKKβ
Authors: Pérez David J. , Zakai Uzma I. , Guo Song , Guzei Ilia A. , Gómez-Sandoval Zeferino , Razo-Hernández Rodrigo Said , West Robert , Ramos-Organillo Ángel
Published: November 2015

The synthesis and characterisation of new silicon-containing amides and esters derived from ibuprofen is reported. These compounds were tested against nuclear transcription factor κβ (NF-κβ). Higher inhibition values than those of ibuprofen were achieved by the new amides 10a–10d; ester derivatives did not show inhibitory activity. The cytotoxicity of these new derivatives was screened; none of them displayed significant toxicity at the screened doses. A molecular docking calculation on IKKβ (an enzyme related to NF-κβ activation) was carried out and the results showed that the amides interact better than ibuprofen with key residues, which are important to the inhibition of IKKβ.
Ralph Tate, his Natural History Museum at the University of Adelaide and the ‘Tate Museum'
Authors: Kidman Barbara
Published: November 2015

Many of Ralph Tate's achievements as the University of Adelaide's foundation Professor of Natural Science arewell known.The focus here is on the quite remarkable, but almost forgotten, natural history museum that he built at the University and that after his death was named the Tate Museum. The paper outlines and explains the difficulties that Tate encountered in establishing the museum, the strictly geological focus of his successors and the gradual dispersal of Tate's main collections.
The Australian Science Centre Movement 1980–2000: Part 2—Science Centres in the States
Authors: Bryant Chris , Gore Mike , Stocklmayer Sue
Published: November 2015

Between 1980 and 1995 eight science centres opened across Australia, driven by the enthusiasm of their originators, funded in various ways, but all acknowledging the leadership of the National Science Centre in Canberra. Six of the centres have continued into the twenty-first century and some have changed their original form, but the philosophy of ‘hands-on' science has been preserved.The accounts in this article are based on extensive notes provided by the protagonists.
Paraphyly, modern systematics and the transfer of Dryandra into Banksia (Proteaceae): a response to George
Authors: Thiele K. R. , Weston P. H. , Mast A. R.
Published: November 2015

The transfer of all species of Dryandra into Banksia in 2007, resulting from phylogenetic studies demonstrating that the latter is paraphyletic with respect to the former, generated controversy in some sections of the community. In a recent paper, Alex George, a taxonomist of long standing and monographer of both genera, criticised the transfer, and its subsequent acceptance by the Australian herbarium and plant systematics community. More broadly, George criticised the direction of modern taxonomy, particularly its basis in phylogenetic analysis and monophyly. His criticisms reflect adherence to a largely pre-Darwinian taxonomic tradition, methodology, practice and conceptual framework. This framework, developed in the late 18th and early 19th centuries, and later operationalised as the phenetic method, has for most taxonomists been superseded by the phylogenetic framework for taxonomy developed by and following Willi Hennig. The criticism of the Dryandra transfer by George and colleagues on one hand, and its acceptance by the majority of practicing systematists on the other, is thus an example of competition between differing paradigms rather than George’s claimed specific shortcomings of the transfer or the analyses on which it was based.
Patterns of Fish Assemblage Structure and Habitat Use among Main‐ and Side‐Channel Environments in the Lower Kootenai River, Idaho
Authors: Watkins Carson J. , Stevens Bryan S. , Quist Michael C. , Shepard Bradley B. , Ireland Susan C.
Published: November 2015

The lower Kootenai River, Idaho, was sampled during the summers of 2012 and 2013 to evaluate its fish assemblage structure at seven sites within main‐ and side‐channel habitats where large‐scale habitat rehabilitation was undertaken. Understanding the current patterns of fish assemblage structure and their relationships with habitat is important for evaluating the effects of past and future rehabilitation projects on the river. Species‐specific habitat associations were modeled, and the variables that best explained the occurrence and relative abundance of fish were identified in order to guide future habitat rehabilitation so that it benefits native species. The results indicated that the side‐channel habitats supported higher species richness than the main‐channel habitats and that nonnative fishes were closely associated with newly rehabilitated habitats. This research provides valuable insight on the current fish assemblages in the Kootenai River and the assemblage‐level responses that may occur as a result of future rehabilitation activities.
New application ofBacillusstrains for optically purel-lactic acid production: general overview and future prospects
Authors: Poudel Pramod , Tashiro Yukihiro , Sakai Kenji
Published: November 2015

Members of the genus Bacillus are considered to be both, among the best studied and most commonly used bacteria as well as the most still unexplored and the most wide-applicable potent bacteria because novel Bacillus strains are continuously being isolated and used in various areas. Production of optically pure l-lactic acid (l-LA), a feedstock for bioplastic synthesis, from renewable resources has recently attracted attention as a valuable application of Bacillus strains. l-LA fermentation by other producers, including lactic acid bacteria and Rhizopus strains (fungi) has already been addressed in several reviews. However, despite the advantages of l-LA fermentation by Bacillus strains, including its high growth rate, utilization of various carbon sources, tolerance to high temperature, and growth in simple nutritional conditions, it has not been reviewed. This review article discusses new findings on LA-producing Bacillus strains and compares them to other producers. The future prospects for LA-producing Bacillus strains are also discussed.
The Big Dehn Surgery Graph and the link of 𝑆³
Authors: Hoffman Neil , Walsh Genevieve
Published: November 2015

In a talk at the Cornell Topology Festival in 2004, W. Thurston discussed a graph which we call “The Big Dehn Surgery Graph”,

B

\mathcal {B}

. Here we explore this graph, particularly the link of

S
3

S^3

, and prove facts about the geometry and topology of

B

\mathcal {B}

. We also investigate some interesting subgraphs and pose what we believe are important questions about

B

\mathcal {B}

.
On cluster algebras from unpunctured surfaces with one marked point
Authors: Canakci Ilke , Lee Kyungyong , Schiffler Ralf
Published: November 2015

We extend the construction of canonical bases for cluster algebras from unpunctured surfaces to the case where the number of marked points on the boundary is one. We show that the cluster algebra is equal to the upper cluster algebra in this case.
GAR22β regulates cell migration, sperm motility, and axoneme structure
Authors: Gamper Ivonne , Fleck David , Barlin Meltem , Spehr Marc , Sayad Sara El , Kleine Henning , Maxeiner Sebastian , Schalla Carmen , Aydin Gülcan , Hoss Mareike , Litchfield David W. , Lüscher Bernhard , Zenke Martin , Sechi Antonio
Published: November 2015

Spatiotemporal cytoskeleton remodeling is pivotal for cell adhesion and migration. Here we investigated the function of Gas2-related protein on chromosome 22 (GAR22β), a poorly characterized protein that interacts with actin and microtubules. Primary and immortalized GAR22β−/−Sertoli cells moved faster than wild-type cells. In addition, GAR22β−/−cells showed a more prominent focal adhesion turnover. GAR22β overexpression or its reexpression in GAR22β−/−cells reduced cell motility and focal adhesion turnover. GAR22β–actin interaction was stronger than GAR22β–microtubule interaction, resulting in GAR22β localization and dynamics that mirrored those of the actin cytoskeleton. Mechanistically, GAR22β interacted with the regulator of microtubule dynamics end-binding protein 1 (EB1) via a novel noncanonical amino acid sequence, and this GAR22β–EB1 interaction was required for the ability of GAR22β to modulate cell motility. We found that GAR22β is highly expressed in mouse testes, and its absence resulted in reduced spermatozoa generation, lower actin levels in testes, and impaired motility and ultrastructural disorganization of spermatozoa. Collectively our findings identify GAR22β as a novel regulator of cell adhesion and migration and provide a foundation for understanding the molecular basis of diverse cytoskeleton-dependent processes.
Illness Severity and Work Productivity Loss Among Working Adults With Medically Attended Acute Respiratory Illnesses: US Influenza Vaccine Effectiveness Network 2012–2013
Authors: Petrie Joshua G. , Cheng Caroline , Malosh Ryan E. , VanWormer Jeffrey J. , Flannery Brendan , Zimmerman Richard K. , Gaglani Manjusha , Jackson Michael L. , King Jennifer P. , Nowalk Mary Patricia , Benoit Joyce , Robertson Anne , Thaker Swathi N. , Monto Arnold S. , Ohmit Suzanne E.
Published: November 2015

Background.  Influenza causes significant morbidity and mortality, with considerable economic costs, including lost work productivity. Influenza vaccines may reduce the economic burden through primary prevention of influenza and reduction in illness severity.

Methods.  We examined illness severity and work productivity loss among working adults with medically attended acute respiratory illnesses and compared outcomes for subjects with and without laboratory-confirmed influenza and by influenza vaccination status among subjects with influenza during the 2012–2013 influenza season.

Results.  Illnesses laboratory-confirmed as influenza (ie, cases) were subjectively assessed as more severe than illnesses not caused by influenza (ie, noncases) based on multiple measures, including current health status at study enrollment (≤7 days from illness onset) and current activity and sleep quality status relative to usual. Influenza cases reported missing 45% more work hours (20.5 vs 15.0; P < .001) than noncases and subjectively assessed their work productivity as impeded to a greater degree (6.0 vs 5.4; P < .001). Current health status and current activity relative to usual were subjectively assessed as modestly but significantly better for vaccinated cases compared with unvaccinated cases; however, no significant modifications of sleep quality, missed work hours, or work productivity loss were noted for vaccinated subjects.

Conclusions.  Influenza illnesses were more severe and resulted in more missed work hours and productivity loss than illnesses not confirmed as influenza. Modest reductions in illness severity for vaccinated cases were observed. These findings highlight the burden of influenza illnesses and illustrate the importance of laboratory confirmation of influenza outcomes in evaluations of vaccine effectiveness.