Newton-Krylov-Schwarz algorithms for the 2D full potential equation
Cai, Xiao-Chuan; Gropp, W.D.; Keyes, D.E.
1996-12-31
We study parallel two-level overlapping Schwarz algorithms for solving nonlinear finite element problems, in particular, for the full potential equation of aerodynamics discretized in two dimensions with bilinear elements. The main algorithm, Newton-Krylov-Schwarz (NKS), employs an inexact finite-difference Newton method and a Krylov space iterative method, with a two-level overlapping Schwarz method as a preconditioner. We demonstrate that NKS, combined with a density upwinding continuation strategy for problems with weak shocks, can be made robust for this class of mixed elliptic-hyperbolic nonlinear partial differential equations, with proper specification of several parameters. We study upwinding parameters, inner convergence tolerance, coarse grid density, subdomain overlap, and the level of fill-in in the incomplete factorization, and report favorable choices for numerical convergence rate and overall execution time on a distributed-memory parallel computer.
Efficient 2d full waveform inversion using Fortran coarray
NASA Astrophysics Data System (ADS)
Ryu, Donghyun; Kim, ahreum; Ha, Wansoo
2016-04-01
We developed a time-domain seismic inversion program using the coarray feature of the Fortran 2008 standard to parallelize the algorithm. We converted a 2d acoustic parallel full waveform inversion program with Message Passing Interface (MPI) to a coarray program and examined performance of the two inversion programs. The results show that the speed of the waveform inversion program using the coarray is slightly faster than that of the MPI version. The standard coarray lacks features for collective communication; however, it can be improved in following standards since it is introduced recently. The parallel algorithm can be applied for 3D seismic data processing.
A full 2D IDCT with extreme low complexity
NASA Astrophysics Data System (ADS)
Navarro, Antonio; Silva, Antonio; Reznik, Yuriy
2007-09-01
In the context of a Call for Proposal for integer IDCTs issued by MPEG in July 2005, a full 2D integer IDCT based on a previous Feig and Winograd's work has been proposed. It achieves a high precision by meeting all IEEE1180 conditions and is suitable of implementation on hardware since it can be performed only with shifts and additions. Furthermore, it can be useful in high video resolution scenarios like in 720p/1080i/p due to its feedforward operation mode without any loop as usual in row-column implementations. The proposed transformation can be implemented without changing other functional blocks either at the encoder or at the decoder or alternatively as a scaled version incorporating the scaling factors into the dequantization stage. Our algorithm uses only 1328 operations for 8x8 blocks, including scaling factors.
Full-waveform inversion in 2D VTI media
NASA Astrophysics Data System (ADS)
Kamath, Nishant
Full-waveform inversion (FWI) is a technique designed to produce a high-resolution model of the subsurface by using information contained in entire seismic waveforms. This thesis presents a methodology for FWI in elastic VTI (transversely isotropic with a vertical axis of symmetry) media and discusses synthetic results for heterogeneous VTI models. First, I develop FWI for multicomponent data from a horizontally layered VTI model. The reflectivity method, which permits computation of only PP reflections or a combination of PP and PSV events, is employed to model the data. The Gauss-Newton technique is used to invert for the interval Thomsen parameters, while keeping the densities fixed at the correct values. Eigenvalue/eigenvector decompostion of the Hessian matrix helps analyze the sensitivity of the objective function to the model parameters. Whereas PP data alone are generally sufficient to constrain all four Thomsen parameters even for conventional spreads, including PS reflections provides better constraints, especially for the deeper part of the model. Next, I derive the gradients of the FWI objective function with respect to the stiffness coefficients of arbitrarily anisotropic media by employing the adjoint-state method. From these expressions, it is straightforward to compute the gradients for parameters of 2D heterogeneous VTI media. FWI is implemented in the time domain with the steepest-descent method used to iteratively update the model. The algorithm is tested on transmitted multicomponent data generated for Gaussian anomalies in Thomsen parameters embedded in homogeneous VTI media. To test the sensitivity of the objective function to different model parameters, I derive an an- alytic expression for the Frechet kernel of FWI for arbitrary anisotropic symmetry by using the Born approximation and asymptotic Green's functions. The amplitude of the kernel, which represents the radiation pattern of a secondary source (that source describes a perturbation
2-D acoustic VTI full waveform inversion for CCS monitoring
NASA Astrophysics Data System (ADS)
KIM, S.; Kim, W. K.; Min, D. J.; Jeong, W.; OH, J. W.
2014-12-01
These days many geophysicists have been working not only for oil and gas exploration but also for CO2 monitoring for CCS (Carbon Capture and storage). When CO2 is injected and stored to the target layer, it changes the physical properties of subsurface media like p-wave velocity, density and so on. Seismic method is one of the most widely used geophysical methods for CO2 monitoring, because it can delineate physical properties of subsurface media. To prevent CO2 from leaking out of reservoirs, most target areas require caprocks, and shale often acts as a caprock. However, shale has a strong anisotropic property. Without considering the anisotropic property of subsurface media, interpretations of seismic monitoring data can distort the CO2distribution or movement in the subsurface media. For computational efficiency, seismic data interpretation based on acoustic VTI (Vertical Transversely Isotropic) wave equations has been commonly done although it does not consider the shear waves. To investigate the importance of considering anisotropic properties in acoustic FWI (full waveform inversion) for CO2 monitoring, we compare results obtained by the acoustic VTI FWI with those of the conventional acoustic FWI for isotropic case in the frequency domain. Both methods are based on the node-based finite-element method. Numerical examples show that neglecting anisotropic properties of subsurface media can distort distribution of CO2 and degrade reliability of subsurface image obtained by FWI. Acknowledgements This work was supported by the Human Resources Development program (No. 20134010200510) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean government Ministry of Trade, Industry, and Energy and by the "Development of Technology for CO2 Marine Geological Storage" grant funded by the Ministry of Oceans and Fisheries of Korea.
Emerging and potential opportunities for 2D flexible nanoelectronics
NASA Astrophysics Data System (ADS)
Zhu, Weinan; Park, Saungeun; Akinwande, Deji
2016-05-01
The last 10 years have seen the emergence of two-dimensional (2D) nanomaterials such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP) among the growing portfolio of layered van der Waals thin films. Graphene, the prototypical 2D material has advanced rapidly in device, circuit and system studies that has resulted in commercial large-area applications. In this work, we provide a perspective of the emerging and potential translational applications of 2D materials including semiconductors, semimetals, and insulators that comprise the basic material set for diverse nanosystems. Applications include RF transceivers, smart systems, the so-called internet of things, and neurotechnology. We will review the DC and RF electronic performance of graphene and BP thin film transistors. 2D materials at sub-um channel length have so far enabled cut-off frequencies from baseband to 100GHz suitable for low-power RF and sub-THz concepts.
2D Potential theory using complex functions and conformal mapping
NASA Astrophysics Data System (ADS)
Le Maire, Pauline; Munschy, Marc
2016-04-01
For infinitely horizontally extended bodies, functions that describe potential and field equations (gravity and magnetics) outside bodies are 2D and harmonic. The consequence of this property is that potential and field equations can be written as complex analytic functions. We define these complex functions whose real part is the commonly used real function and imaginary part is its Hilbert transform. Using data or synthetic cases the transformation is easily performed in the Fourier domain by setting to zero all values for negative frequencies. Written as complex functions of the complex variable, equations of potential and field in gravity and magnetics for different kinds of geometries are simple and correspond to powers of the inverse of the distance. For example, it is easily shown that for a tilted dyke, the dip and the apparent inclination have the same effect on the function and consequently that it is not possible, with data, to compute one of both values without knowing the other. Conformal mapping is an original way to display potential field functions. Considering that the complex variable corresponds to the real axis, complex potential field functions resume to a limaçon, a curve formed by the path of the point fixed to a circle when that circle rolls around the outside of another circle. For example, the point corresponding to the maximum distance to the origin of the complex magnetic field due to a cylinder, corresponds to the maximum of the analytic signal as defined by Nabighan in 1972 and its phase corresponds to the apparent inclination. Several applications are shown in different geological contexts using aeromagnetic data.
Full potential multiple scattering theory
MacLaren, J.M.
1994-10-20
A practical method for performing self-consistent electronic structure calculations based upon full-potential multiple-scattering theory is presented. Solutions to the single site Schroedinger equation are obtained by solving coupled channel integral equations for a potential which is analytically continued out to the circumscribing sphere. This potential coincides with the full cell potential inside each atomic cell. Scattering matrices and wavefunctions for the full cell potential are obtained from surface Wronskian relations. The charge density is obtained from the single particle Green`s function. This Green`s function is computed using the cell scattering matrices and wavefunctions using the layer multiple scattering theory. Self consistent solutions require a solution at each iteration to the Poisson equation. The Poisson equation is solved using a variational cellular method. In the approach a local solution to each cell is augmented by adding a series of regular harmonics (solutions to Laplace`s equation). Minimizing the coulomb energy, subject to continuity of the potential across all cell boundary provides an expression for the coefficients of the regular harmonics. This method is applied to BCC Nb. Calculated properties converge well in angular momentum and show comparable accuracy to full potential linearized muffin-tin orbital calculations.
CAS2D- NONROTATING BLADE-TO-BLADE, STEADY, POTENTIAL TRANSONIC CASCADE FLOW ANALYSIS CODE
NASA Technical Reports Server (NTRS)
Dulikravich, D. S.
1994-01-01
An exact, full-potential-equation model for the steady, irrotational, homoentropic, and homoenergetic flow of a compressible, inviscid fluid through a two-dimensional planar cascade together with its appropriate boundary conditions has been derived. The CAS2D computer program numerically solves an artificially time-dependent form of the actual full-potential-equation, providing a nonrotating blade-to-blade, steady, potential transonic cascade flow analysis code. Comparisons of results with test data and theoretical solutions indicate very good agreement. In CAS2D, the governing equation is discretized by using type-dependent, rotated finite differencing and the finite area technique. The flow field is discretized by providing a boundary-fitted, nonuniform computational mesh. This mesh is generated by using a sequence of conformal mapping, nonorthogonal coordinate stretching, and local, isoparametric, bilinear mapping functions. The discretized form of the full-potential equation is solved iteratively by using successive line over relaxation. Possible isentropic shocks are captured by the explicit addition of an artificial viscosity in a conservative form. In addition, a four-level, consecutive, mesh refinement feature makes CAS2D a reliable and fast algorithm for the analysis of transonic, two-dimensional cascade flows. The results from CAS2D are not directly applicable to three-dimensional, potential, rotating flows through a cascade of blades because CAS2D does not consider the effects of the Coriolis force that would be present in the three-dimensional case. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 series computer with a central memory requirement of approximately 200K of 8 bit bytes. The CAS2D program was developed in 1980.
2D full wave modeling for a synthetic Doppler backscattering diagnostic
Hillesheim, J. C.; Schmitz, L.; Kubota, S.; Rhodes, T. L.; Carter, T. A.; Holland, C.
2012-10-15
Doppler backscattering (DBS) is a plasma diagnostic used in tokamaks and other magnetic confinement devices to measure the fluctuation level of intermediate wavenumber (k{sub {theta}}{rho}{sub s}{approx} 1) density fluctuations and the lab frame propagation velocity of turbulence. Here, a synthetic DBS diagnostic is described, which has been used for comparisons between measurements in the DIII-D tokamak and predictions from nonlinear gyrokinetic simulations. To estimate the wavenumber range to which a Gaussian beam would be sensitive, a ray tracing code and a 2D finite difference, time domain full wave code are used. Experimental density profiles and magnetic geometry are used along with the experimental antenna and beam characteristics. An example of the effect of the synthetic diagnostic on the output of a nonlinear gyrokinetic simulation is presented.
2D full wave modeling for a synthetic Doppler backscattering diagnostica)
NASA Astrophysics Data System (ADS)
Hillesheim, J. C.; Holland, C.; Schmitz, L.; Kubota, S.; Rhodes, T. L.; Carter, T. A.
2012-10-01
Doppler backscattering (DBS) is a plasma diagnostic used in tokamaks and other magnetic confinement devices to measure the fluctuation level of intermediate wavenumber (kθρs ˜ 1) density fluctuations and the lab frame propagation velocity of turbulence. Here, a synthetic DBS diagnostic is described, which has been used for comparisons between measurements in the DIII-D tokamak and predictions from nonlinear gyrokinetic simulations. To estimate the wavenumber range to which a Gaussian beam would be sensitive, a ray tracing code and a 2D finite difference, time domain full wave code are used. Experimental density profiles and magnetic geometry are used along with the experimental antenna and beam characteristics. An example of the effect of the synthetic diagnostic on the output of a nonlinear gyrokinetic simulation is presented.
Full 2D observation of water surface elevation from SWOT under different flow conditions
NASA Astrophysics Data System (ADS)
Domeneghetti, Alessio; Schumann, Guy; Rui, Wei; Durand, Michael; Pavelsky, Tamlin
2016-04-01
The upcoming Surface Water and Ocean Topography (SWOT) satellite mission is a joint project of NASA, Centre National d'Etudes Spatiales (CNES, France), the Canadian Space Agency, and the Space Agency of the UK that will provide a first global, high-resolution observation of ocean and terrestrial water surface heights. Characterized by an observation swath of 120 km and an orbit repeat interval of about 21 days, SWOT will provide unprecedented bi-dimensional observations of rivers wider than 50-100 m. Despite many research activities that have investigated potential uses of remotely sensed data from SWOT, potentials and limitations of the spatial observations provided by the satellite mission for flood modeling still remain poorly understood and investigated. In this study we present a first analysis of the spatial observation of water surface elevation that is expected from SWOT for a 140 km reach of the middle-lower portion of the Po River, in Northern Italy. The river stretch is characterized by a main channel varying from 200-500 m in width and a floodplain that can be as wide as 5 km and that is delimited by a system of major embankments. The reconstruction of the hydraulic behavior of the Po River is performed by means of a quasi-2d model built with detailed topographic and bathymetric information (LiDAR, 2 m resolution), while the simulation of the spatial observation sensed by SWOT is performed with a SWOT simulator that mimics the satellite sensor characteristics. Referring to water surface elevations associated with different flow conditions (maximum, minimum and average flow reproduced by means of the quasi-2d numerical model) this work provides a first characterization of the spatial observations provided by SWOT and highlights the strengths and limitations of the expected products. By referring to a real river reach the analysis provides a credible example of the type of spatial observations that will be available after launch of SWOT and offers a first
Long-Read Single Molecule Real-Time Full Gene Sequencing of Cytochrome P450-2D6.
Qiao, Wanqiong; Yang, Yao; Sebra, Robert; Mendiratta, Geetu; Gaedigk, Andrea; Desnick, Robert J; Scott, Stuart A
2016-03-01
The cytochrome P450-2D6 (CYP2D6) enzyme metabolizes ∼25% of common medications, yet homologous pseudogenes and copy number variants (CNVs) make interrogating the polymorphic CYP2D6 gene with short-read sequencing challenging. Therefore, we developed a novel long-read, full gene CYP2D6 single molecule real-time (SMRT) sequencing method using the Pacific Biosciences platform. Long-range PCR and CYP2D6 SMRT sequencing of 10 previously genotyped controls identified expected star (*) alleles, but also enabled suballele resolution, diplotype refinement, and discovery of novel alleles. Coupled with an optimized variant-calling pipeline, CYP2D6 SMRT sequencing was highly reproducible as triplicate intra- and inter-run nonreference genotype results were completely concordant. Importantly, targeted SMRT sequencing of upstream and downstream CYP2D6 gene copies characterized the duplicated allele in 15 control samples with CYP2D6 CNVs. The utility of CYP2D6 SMRT sequencing was further underscored by identifying the diplotypes of 14 samples with discordant or unclear CYP2D6 configurations from previous targeted genotyping, which again included suballele resolution, duplicated allele characterization, and discovery of a novel allele and tandem arrangement. Taken together, long-read CYP2D6 SMRT sequencing is an innovative, reproducible, and validated method for full-gene characterization, duplication allele-specific analysis, and novel allele discovery, which will likely improve CYP2D6 metabolizer phenotype prediction for both research and clinical testing applications.
Progress towards ultracold gases in arbitrary 2D potentials
NASA Astrophysics Data System (ADS)
Corcovilos, Theodore
2016-05-01
We describe our progress in building an apparatus for investigating degenerate quantum gases of potassium in arbitrary two-dimensional optical potentials. The optical potentials are created by holographic projection of an image created using a MEMS mirror array. Systems we would like to study with this experiment are quantum simulations of bosons and fermions at crystal heterojunctions and systems with well defined boundaries, including topological edge states. Funding provided by the Charles E Kaufman Foundation, a part of the Pittsburgh Foundation.
Efficient 2D and 3D multiparameters frequency-domain full waveform inversion (Invited)
NASA Astrophysics Data System (ADS)
Virieux, J.; Operto, S.; Ribodetti, A.; Ben Hadj Ali, H.; Brossier, R.; Etienne, V.; Gholami, Y.; Hu, G.; Jia, Y.; Pageot, D.; Prieux, V.
2010-12-01
With the tremendous increase of the computational power provided by large-scale distributed-memory platforms and the development of dense 3D multi-component wide-aperture/wide-azimuth surveys, full waveform inversion (FWI) introduced in geophysics by Albert Tarantola has become a re-emerging technique to build high-resolution velocity models of the subsurface. Because of the cost of the forward modeling and the high dimensionality of the model space, full waveform inversion is actually a local optimization problem, the aim of which is the minimization of the misfit between the recorded and modeled seismic wavefields. Among all possible minimization criteria, the L1 norm provides the most robust and easy-to-tune criterion. With such criterion, white noise in all seismograms with outliers does not prevent the convergence to the nearly same minimum as for noise-free data. The frequency formulation of the FWI allows coarse sampling of the frequencies data over few frequencies for the reconstruction of the medium when wide-aperture geometries are considered. A preconditioned quasi-Newton L-BFGS modified algorithm provides scaled gradients of the misfit function for each class of parameters. The gradient is computed by the adjoint-state method where the forward field is stored in the core memory of the computer while computing the backpropagation of residuals for cross-correlation at each point of the medium, thanks to the frequency-domain approach. We are using a sequential multiscale hierarchical inversion algorithm with two nested levels of data preconditioning with respect to frequency and first-arrival time. We are able to reconstruct both Vp and Vs velocity structures in various offshore and onshore environments various configurations of crustal investigation where both body waves (and surface) waves are progressively included in the inversion scheme. Solving the forward problem for 2D geometry could be efficiently performed in frequency by using a direct solver
Cooperative Cross-Hole Ert and 2-D Full-Waveform Gpr Inversion
NASA Astrophysics Data System (ADS)
Bouchedda, A.; Chouteau, M.
2012-12-01
Recent advances in high-performance computing make full-waveform inversion (FWI) of cross-hole ground penetrating data feasible. FWI, where high-resolution imaging at half the propagated wavelength is expected, allows a better resolution in comparison to ray-based tomography. The inverse problem is generally solved using local optimization algorithms that can converge to local minimum depending on the selection of starting model, nonlinearity of the problem, lack of low frequencies, presence of noise, and approximate modeling of the wave-physics complexity. In this work, multiscale FWI strategy is combined cooperatively with electrical resistivity tomography (ERT) to mitigate the nonlinearity and ill-posedness of FWI and improve the ERT resolution. In the FWI, the gradient of the misft function is generally dominated by the high frequencies. This behaviour can potentially be the cause of convergence into local minima, as the determination of the high frequencies depends in turn on the accuracy of the low frequencies. Different from taking advantage of low frequencies in the data, the proposed multiscale FWI reduces the number of model parameters and yields low frequencies in the model space using a regularization method that consists of imposing an L1-norm penalty in the wavelet domain. The minimization of the L1-norm penalty is carried out using an accelerated iterative soft-thresholding algorithm. As wavelet transforms provide estimates of the local frequency content of the conductivity or permittivity images, the thresholds are used to control the frequency content in the model space. Generally, a high threshold value is chosen for the 20th first iterations in order to enhance the update of the low frequencies. After that the soft thresholding step tries to find the best thresholds to maximize the structural similarities between conductivity and permittivity images. The initial velocity model for FWI is built from first-arrival traveltime tomography, whereas the
Ren, X; Domier, C W; Kramer, G; Luhmann, N C; Muscatello, C M; Shi, L; Tobias, B J; Valeo, E
2014-11-01
A synthetic microwave imaging reflectometer (MIR) diagnostic employing the full-wave reflectometer code (FWR2D) has been developed and is currently being used to guide the design of real systems, such as the one recently installed on DIII-D. The FWR2D code utilizes real plasma profiles as input, and it is combined with optical simulation tools for synthetic diagnostic signal generation. A detailed discussion of FWR2D and the process to generate the synthetic signal are presented in this paper. The synthetic signal is also compared to a prescribed density fluctuation spectrum to quantify the imaging quality. An example is presented with H-mode-like plasma profiles derived from a DIII-D discharge, where the MIR focal is located in the pedestal region. It is shown that MIR is suitable for diagnosing fluctuations with poloidal wavenumber up to 2.0 cm(-1) and fluctuation amplitudes less than 5%.
Quantum-Carnot engine for particle confined to 2D symmetric potential well
NASA Astrophysics Data System (ADS)
Belfaqih, Idrus Husin; Sutantyo, Trengginas Eka Putra; Prayitno, T. B.; Sulaksono, Anto
2015-09-01
Carnot model of heat engine is the most efficient cycle consisting of isothermal and adiabatic processes which are reversible. Although ideal gas usually used as a working fluid in the Carnot engine, Bender used quantum particle confined in 1D potential well as a working fluid. In this paper, by following Bender we generalize the situation to 2D symmetric potential well. The efficiency is express as the ratio of the initial length of the system to the final length of the compressed system. The result then is shown that for the same ratio, 2D potential well is more efficient than 1D potential well.
Quantum-Carnot engine for particle confined to 2D symmetric potential well
Belfaqih, Idrus Husin Sutantyo, Trengginas Eka Putra Prayitno, T. B.; Sulaksono, Anto
2015-09-30
Carnot model of heat engine is the most efficient cycle consisting of isothermal and adiabatic processes which are reversible. Although ideal gas usually used as a working fluid in the Carnot engine, Bender used quantum particle confined in 1D potential well as a working fluid. In this paper, by following Bender we generalize the situation to 2D symmetric potential well. The efficiency is express as the ratio of the initial length of the system to the final length of the compressed system. The result then is shown that for the same ratio, 2D potential well is more efficient than 1D potential well.
CAS2D: FORTRAN program for nonrotating blade-to-blade, steady, potential transonic cascade flows
NASA Technical Reports Server (NTRS)
Dulikravich, D. S.
1980-01-01
An exact, full-potential-equation (FPE) model for the steady, irrotational, homentropic and homoenergetic flow of a compressible, homocompositional, inviscid fluid through two dimensional planar cascades of airfoils was derived, together with its appropriate boundary conditions. A computer program, CAS2D, was developed that numerically solves an artificially time-dependent form of the actual FPE. The governing equation was discretized by using type-dependent, rotated finite differencing and the finite area technique. The flow field was discretized by providing a boundary-fitted, nonuniform computational mesh. The mesh was generated by using a sequence of conforming mapping, nonorthogonal coordinate stretching, and local, isoparametric, bilinear mapping functions. The discretized form of the FPE was solved iteratively by using successive line overrelaxation. The possible isentropic shocks were correctly captured by adding explicitly an artificial viscosity in a conservative form. In addition, a three-level consecutive, mesh refinement feature makes CAS2D a reliable and fast algorithm for the analysis of transonic, two dimensional cascade flows.
Quantum damped oscillator II: Bateman's Hamiltonian vs. 2D parabolic potential barrier
Chruscinski, Dariusz . E-mail: darch@phys.uni.torun.pl
2006-04-15
We show that quantum Bateman's system which arises in the quantization of a damped harmonic oscillator is equivalent to a quantum problem with 2D parabolic potential barrier known also as 2D inverted isotropic oscillator. It turns out that this system displays the family of complex eigenvalues corresponding to the poles of analytical continuation of the resolvent operator to the complex energy plane. It is shown that this representation is more suitable than the hyperbolic one used recently by Blasone and Jizba.
NASA Astrophysics Data System (ADS)
Desmet, Cloé; Valsesia, Andrea; Colpo, Pascal; Rossi, François
2015-06-01
In the context of the extensive use of engineered nanomaterials (ENMs) in consumer products, industrial applications and nanomedicine, there is an important need of new methods for an exhaustive characterization of their physicochemical properties. Among them, surface hydrophobicity is considered as a key factor to be controlled, in particular for nanomedicine applications1,2. The proposed study demonstrates the proof-of-concept of an inexpensive characterization process, enabling the sorting of ENMs according to their hydrophobicity and surface charge, together with the classical characterization of size and shape. The detection platform is based on the use of a surface modified through plasma polymer and layer-by-layer polyelectrolyte deposition in order to generate areas of tuned surface properties to bind ENMs selectively by hydrophobic forces and electrostatic interactions. The key advantages of such a device is the decrease of time and assay costs thanks to the all-in-one characterization process and the multiplexing that could replace the use of different methods and expensive equipment to give equivalent results. In this way, the full characterization of NP could be expanded in all the areas covering NP-related applications.
Origin of energetic ions observed in the terrestrial ion foreshock : 2D full-particle simulations
NASA Astrophysics Data System (ADS)
Savoini, Philippe; Lembege, bertrand
2016-04-01
Collisionless shocks are well-known structures in astrophysical environments which dissipate bulk flow kinetic energy and accelerate large fraction of particle. Spacecrafts have firmly established the existence of the so-called terrestrial foreshock region magnetically connected to the shock and filled by two distinct populations in the quasi-perpendicular shock region (i.e. for 45r{ } ≤ quad θ Bn quad ≤ 90r{ }, where θ Bn is the angle between the shock normal and the upstream magnetic field) : (i) the field-aligned ion beams or `` FAB '' characterized by a gyrotropic distributionsout{,} and (ii) the gyro-phase bunched ions or `` GPB '' characterized by a NON gyrotropic distribution. The present work is based on the use of two dimensional PIC simulation of a curved shock and associated foreshock region where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described by a self consistent approach. Our previous analysis (Savoini et Lembège, 2015) has evidenced that these two types of backstreaming populations can originate from the shock front itself without invoking any local diffusion by ion beam instabilities. Present results are focussed on individual ion trajectories and evidence that "FAB" population is injected into the foreshock mainly along the shock front whereas the "GPB" population penetrates more deeply the shock front. Such differences explain why the "FAB" population loses their gyro-phase coherency and become gyrotropic which is not the case for the "GPB". The impact of these different injection features on the energy gain for each ion population will be presented in détails. Savoini, P. and B. Lembège (2015), `` Production of nongyrotropic and gyrotropic backstreaming ion distributions in the quasi-perpendicular ion foreshock région '', J. Geophys. Res., 120, pp 7154-7171, doi = 10.1002/2015JA021018.
NASA Astrophysics Data System (ADS)
Sirait, S. H.; Edison, R. E.; Baidillah, M. R.; Taruno, W. P.; Haryanto, F.
2016-08-01
The aim of this study is to simulate the potential distribution of 2D brain geometry based on two electrodes ECVT. ECVT (electrical capacitance tomography) is a tomography modality which produces dielectric distribution image of a subject from several capacitance electrodes measurements. This study begins by producing the geometry of 2D brain based on MRI image and then setting the boundary conditions on the boundaries of the geometry. The values of boundary conditions follow the potential values used in two electrodes brain ECVT, and for this reason the first boundary is set to 20 volt and 2.5 MHz signal and another boundary is set to ground. Poisson equation is implemented as the governing equation in the 2D brain geometry and finite element method is used to solve the equation. Simulated Hodgkin-Huxley action potential is applied as disturbance potential in the geometry. We divide this study into two which comprises simulation without disturbance potential and simulation with disturbance potential. From this study, each of time dependent potential distributions from non-disturbance and disturbance potential of the 2D brain geometry has been generated.
Melton-Celsa, Angela R; O'Brien, Alison D; Feng, Peter C H
2015-11-01
Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are food- and waterborne pathogens that are often transmitted via beef products or fresh produce. STEC strains cause both sporadic infections and outbreaks, which may result in hemorrhagic colitis and hemolytic uremic syndrome. STEC strains may elaborate Stx1, Stx2, and/or subtypes of those toxins. Epidemiological evidence indicates that STEC that produce subtypes Stx2a, Stx2c, and/or Stx2d are more often associated with serious illness. The Stx2d subtype becomes more toxic to Vero cells after incubation with intestinal mucus or elastase, a process named "activation." Stx2d is not generally found in the E. coli serotypes most commonly connected to STEC outbreaks. However, STEC strains that are stx2d positive can be isolated from foods, an occurrence that gives rise to the question of whether those food isolates are potential human pathogens. In this study, we examined 14 STEC strains from fresh produce that were stx2d positive and found that they all produced the mucus-activatable Stx2d and that a subset of the strains tested were virulent in streptomycin-treated mice.
NASA Astrophysics Data System (ADS)
Gelis, C.; Virieux, J.; Grandjean, G.; Operto, S.
2005-12-01
The superficial weathered zone, few hundreds meters thick, presents highly variable and complex near-surface structures. Energetic seismic surface waves, often called ground roll, may hide information coming from deeper areas. Moreover near-surface anomalies (cavities, overthrusts) are quite important and, therefore, detecting heterogeneities in near-surface areas and quantifying their physical properties is still a challenge for seismic imaging. Since heterogeneities are located in near-surface areas, both surface and body waves induce complex footprints in seismic data. The propagation of 2D P-SV is performed in a frequency domain modeling. This frequency formulation takes into account attenuating behavior and efficiently takes benefit of multisource and multireceiver configurations. A new finite-difference stencil of second order using rotated derivatives axes (Saenger et al., 2000) simulates surface waves precisely and remains stable nearby the free surface and/or rapidly-varying zones. It will be the forward problem kernel of our approach. We follow the matrix formalism of Pratt et al. (1998) and perform a linearized inversion in the least-square sense, since heterogeneities of reasonable amplitudes towards the surrounding medium are considered. We use the gradient method to perform the full waveform inversion for elastic waves. In this formulation we take only the Hessian diagonal part and use a parabolic approximation to find the stepping in the gradient direction. To compute Fréchet derivatives, we resort to the Born and the Rytov approximations and evaluate their performances in transmission and reflection acquisitions geometries. We test as well the influence of the inverted parameters choice. Moreover we highlight the influence of data preconditioning that must be particularly efficient to deal with both body and surface waves. We apply this elastic full waveform inversion to near-surface data, containing strong surface waves and acquired just above a
The potential of 2D Kalman filtering for soil moisture data assimilation
Technology Transfer Automated Retrieval System (TEKTRAN)
We examine the potential for parameterizing a two-dimensional (2D) land data assimilation system using spatial error auto-correlation statistics gleaned from a triple collocation analysis and the triplet of: (1) active microwave-, (2) passive microwave- and (3) land surface model-based surface soil ...
NASA Astrophysics Data System (ADS)
Kangliang, Wei; Xiaoyan, Liu; Gang, Du; Ruqi, Han
2010-08-01
We demonstrate a two-dimensional (2D) full-band ensemble Monte-Carlo simulator for heterostructures, which deals with carrier transport in two different semiconductor materials simultaneously as well as at the boundary by solving self-consistently the 2D Poisson and Boltzmann transport equations (BTE). The infrastructure of this simulator, including the energy bands obtained from the empirical pseudo potential method, various scattering mechanics employed, and the appropriate treatment of the carrier transport at the boundary between two different semiconductor materials, is also described. As verification and calibration, we have performed a simulation on two types of silicon-germanium (Si-Ge) heterojunctions with different doping profiles—the p-p homogeneous type and the n-p inhomogeneous type. The current-voltage characteristics are simulated, and the distributions of potential and carrier density are also plotted, which show the validity of our simulator.
Drift instability of a 2D magnetoplasma in a periodic potential
NASA Astrophysics Data System (ADS)
Fessatidis, Vassilios; Horing, Norman J. M.; Sawamura, Makoto
2010-01-01
We examine the drift instability of a magnetized 2D electron plasma in a weak periodic potential, taking account of a steady current. In this, we treat a strong magnetic field inducing Landau quantization, and analyze both the inter- and intra-Landau band aspects of the magneto-plasmon spectrum within the framework of the random phase approximation, determining the occurrence of magnetoplasmon instability as a function of drift speed.
Monitoring of injected CO2 using the seismic full waveform inversion for 2-D elastic VTI media
NASA Astrophysics Data System (ADS)
Kim, W. K.; Min, D. J.; KIM, S.; Shin, Y.; Moon, S.
2014-12-01
To monitor the injected CO2 in the subsurface, seismic monitoring techniques are extensively applied because of its high resolution. Among the seismic monitoring techniques, seismic full waveform inversion (FWI) has high applicability because it can delineate parameter changes by injected CO2. When seismic FWIs are applied, subsurface media can be generally assumed to be isotropic. However, most subsurface media are not isotropic, and shale is a representative anisotropic medium, particularly vertical transversely isotropic (VTI) medium, which is often encountered as a barrier to injected CO2. Thus, anisotropic properties of subsurface media are important for monitoring of injected CO2. For these issues, we need to consider anisotropy of subsurface media when seismic FWIs are applied as a monitoring tool for CO2 sequestration. In this study, we performed seismic FWI for 2-D elastic VTI media to investigate the effects of anisotropic properties in CO2 monitoring. For this numerical test, we assumed a geological model, which copies after one of CO2 storage prospects in Korea. We also applied seismic FWI algorithm for 2-D elastic isotropic media for comparison. From this comparison, we noticed that we can obtain more reliable results when we apply the anisotropic FWI algorithm. Numerical examples indicate that we should apply the anisotropic FWI algorithm rather than the isotropic FWI algorithm when we interpret seismic monitoring data acquired in anisotropic media to increase the success of monitoring for injected CO2. Our numerical results can also be used as references for real seismic monitoring of the Korea CO2 sequestration projects in the near future. Acknowledgements This work was supported by the Human Resources Development program (No. 20134010200510) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean government Ministry of Trade, Industry, and Energy and by the "Development of Technology for CO2 Marine
Full potential unsteady computations including aeroelastic effects
NASA Technical Reports Server (NTRS)
Shankar, Vijaya; Ide, Hiroshi
1989-01-01
A unified formulation is presented based on the full potential framework coupled with an appropriate structural model to compute steady and unsteady flows over rigid and flexible configurations across the Mach number range. The unsteady form of the full potential equation in conservation form is solved using an implicit scheme maintaining time accuracy through internal Newton iterations. A flux biasing procedure based on the unsteady sonic reference conditions is implemented to compute hyperbolic regions with moving sonic and shock surfaces. The wake behind a trailing edge is modeled using a mathematical cut across which the pressure is satisfied to be continuous by solving an appropriate vorticity convection equation. An aeroelastic model based on the generalized modal deflection approach interacts with the nonlinear aerodynamics and includes both static as well as dynamic structural analyses capability. Results are presented for rigid and flexible configurations at different Mach numbers ranging from subsonic to supersonic conditions. The dynamic response of a flexible wing below and above its flutter point is demonstrated.
NASA Astrophysics Data System (ADS)
de La Barrera, Sergio; Mende, Patrick; Li, Jun; Feenstra, Randall; Lin, Yu-Chuan; Robinson, Joshua; Vishwanath, Suresh; Xing, Huili
Among the many properties that evolve as isolated 2D materials are brought together to form a heterostructure, rearrangement of charges between layers due to unintentional doping results in dipole fields at the interface, which critically affect the electronic properties of the structure. Here we report a method for directly measuring work function differences, and hence electrostatic potential variations, across the surface of 2D materials and heterostructures thereof using low energy electron microscopy (LEEM). Study of MoSe2 grown by molecular beam epitaxy on epitaxial graphene on SiC with LEEM reveals a large work function difference between the MoSe2 and the graphene, indicating charge transfer between the layers and a subsequent dipole layer. In addition to quantifying dipole effects between transition metal dichalcogenides and graphene, direct imaging of the surface, diffraction information, and the spectroscopic dependence of electron reflectivity will be discussed. This work was supported in part by the Center for Low Energy Systems Technology (LEAST), one of the six SRC STARnet Centers, sponsored by MARCO and DARPA.
Potential role of CYP2D6 in the central nervous system
Cheng, Jie; Zhen, Yueying; Miksys, Sharon; Beyoğlu, Diren; Krausz, Kristopher W.; Tyndale, Rachel F.; Yu, Aiming; Idle, Jeffrey R.; Gonzalez, Frank J.
2013-01-01
Cytochrome P450 2D6 (CYP2D6) is a pivotal enzyme responsible for a major human drug oxidation polymorphism in human populations. Distribution of CYP2D6 in brain and its role in serotonin metabolism suggest this CYP2D6 may have a function in central nervous system. To establish an efficient and accurate platform for the study of CYP2D6 in vivo, a transgenic human CYP2D6 (Tg-2D6) model was generated by transgenesis in wild-type C57BL/6 (WT) mice using a P1 phage artificial chromosome clone containing the complete human CYP2D locus, including CYP2D6 gene and 5’- and 3’- flanking sequences. Human CYP2D6 was expressed not only in the liver, but also in brain. The abundance of serotonin and 5-hydroxyindoleacetic acid in brain of Tg-2D6 is higher than in WT mice either basal levels or after harmaline induction. Metabolomics of brain homogenate and cerebrospinal fluid revealed a significant up-regulation of l-carnitine, acetyl-l-carnitine, pantothenic acid, dCDP, anandamide, N-acetylglucosaminylamine, and a down-regulation of stearoyl-l-carnitine in Tg-2D6 mice compared with WT mice. Anxiety tests indicate Tg-2D6 mice have a higher capability to adapt to anxiety. Overall, these findings indicate that the Tg-2D6 mouse model may serve as a valuable in vivo tool to determine CYP2D6-involved neurophysiological metabolism and function. PMID:23614566
Schrödinger equation for non-pure dipole potential in 2D systems
NASA Astrophysics Data System (ADS)
Moumni, M.; Falek, M.
2016-07-01
In this work, we analytically study the Schrödinger equation for the (non-pure) dipolar ion potential V(r) = q/r + Dcosθ/r2, in the case of 2D systems (systems in two-dimensional Euclidean plane) using the separation of variables and the Mathieu equations for the angular part. We give the expressions of eigenenergies and eigenfunctions and study their dependence on the dipole moment D. Imposing the condition of reality on the energies En,m implies that the dipole moment must not exceed a maximum value, otherwise the corresponding bound state disappears. We also find that the s states (m = 0) can no longer exist in the system as soon as the dipole term is present.
Al-Jenoobi, F I; Korashy, H M; Ahad, A; Raish, M; Al-Mohizea, A M; Alam, M A; Al-Suwayeh, S A; Alkharfy, K M
2014-11-01
The aim of current study was to investigate the effect of some commonly used medicinal herbs on the regulation of rat CYP2D gene expression and its metabolic activity. Wistar albino rats were treated for seven consecutive days with selected doses of five commonly used herbs (Trigonella foenum-graecum, Ferula asafoetida, Nigella sativa, Commiphora myrrha and Lepidium sativum). Thereafter, rat livers were harvested and CYP2D mRNA levels were determined by RT-PCR. The metabolic activity of CYP2D was performed on rat hepatic microsomes using dextromethorphan as specific substrate. All investigated herbs produced inhibition of CYP2D mRNA expression and metabolic activity. The inhibitory potential of investigated herbs on rat CYP2D mRNA was in the following order: Commiphora myrrha > Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Ferula asafoetida. Whereas, the inhibitory potential of investigated herbs on CYP2D mediated enzyme metabolic activity was found in following order: Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Commiphora myrrha > Ferula asafoetida. The current study shows that only used herbs reduce CYP2D activity in rat liver microsomes at the transcriptional levels. Such effects could lead to undesirable pharmacological effects of clinically used low therapeutic index CYP2D substrate drugs.
2D multi-parameter elastic seismic imaging by frequency-domain L1-norm full waveform inversion
NASA Astrophysics Data System (ADS)
Brossier, Romain; Operto, Stéphane; Virieux, Jean
2010-05-01
Full waveform inversion (FWI) is becoming a powerful and efficient tool to derive high-resolution quantitative models of the subsurface. In the frequency-domain, computationally efficient FWI algorithms can be designed for wide-aperture acquisition geometries by limiting inversion to few discrete frequencies. However, FWI remains an ill-posed and highly non-linear data-fitting procedure that is sensitive to noise, inaccuracies of the starting model and definition of multiparameter classes. The footprint of the noise in seismic imaging is conventionally mitigated by stacking highly redundant multifold data. However, when the data redundancy is decimated in the framework of efficient frequency-domain FWI, it is essential to assess the sensitivity of the inversion to noise. The impact of the noise in FWI, when applied to decimated data sets, has been marginally illustrated in the past and least-squares minimisation has remained the most popular approach. We investigate in this study the sensitivity of frequency-domain elastic FWI to noise for realistic onshore and offshore synthetic data sets contaminated by ambient random white noise. Four minimisation functionals are assessed in the framework of frequency domain FWI of decimated data: the classical least-square norm (L2), the least-absolute-values norm (L1), and some combinations of both (the Huber and the so-called Hybrid criteria). These functionals are implemented in a massively-parallel, 2D elastic frequency-domain FWI algorithm. A two-level hierarchical algorithm is implemented to mitigate the non-linearity of the inversion in complex environments. The first outer level consists of successive inversions of frequency groups of increasing high-frequency content. This level defines a multi-scale approach while preserving some data redundancy by means of simultaneous inversion of multiple frequencies. The second inner level used complex-valued frequencies for data preconditioning. This preconditioning controls the
Differences in the Toxicological Potential of 2D versus Aggregated Molybdenum Disulfide in the Lung.
Wang, Xiang; Mansukhani, Nikhita D; Guiney, Linda M; Ji, Zhaoxia; Chang, Chong Hyun; Wang, Meiying; Liao, Yu-Pei; Song, Tze-Bin; Sun, Bingbing; Li, Ruibin; Xia, Tian; Hersam, Mark C; Nel, André E
2015-10-01
2D molybdenum disulfide (MoS2 ) has distinct optical and electronic properties compared to aggregated MoS2 , enabling wide use of these materials for electronic and biomedical applications. However, the hazard potential of MoS2 has not been studied extensively. Here, a comprehensive analysis of the pulmonary hazard potential of three aqueous suspended forms of MoS2 -aggregated MoS2 (Agg-MoS2 ), MoS2 exfoliated by lithiation (Lit-MoS2 ), and MoS2 dispersed by Pluronic F87 (PF87-MoS2 )-is presented. No cytotoxicity is detected in THP-1 and BEAS-2B cell lines. However, Agg-MoS2 induces strong proinflammatory and profibrogenic responses in vitro. In contrast, Lit- and PF87-MoS2 have little or no effect. In an acute toxicity study in mice, Agg-MoS2 induces acute lung inflammation, while Lit-MoS2 and PF87-MoS2 have little or no effect. In a subchronic study, there is no evidence of pulmonary fibrosis in response to all forms of MoS2 . These data suggest that exfoliation attenuates the toxicity of Agg-MoS2 , which is an important consideration toward the safety evaluation and use of nanoscale MoS2 materials for industrial and biological applications.
NASA Astrophysics Data System (ADS)
Fernández-Pato, Javier; Caviedes-Voullième, Daniel; García-Navarro, Pilar
2016-05-01
One of the most difficult issues in the development of hydrologic models is to find a rigorous source of data and specific parameters to a given problem, on a given location that enable reliable calibration. In this paper, a distributed and physically based model (2D Shallow Water Equations) is used for surface flow and runoff calculations in combination with two infiltration laws (Horton and Green-Ampt) for estimating infiltration in a watershed. This technique offers the capability of assigning a local and time-dependent infiltration rate to each computational cell depending on the available surface water, soil type or vegetation. We investigate how the calibration of parameters is affected by transient distributed Shallow Water model and the complexity of the problem. In the first part of this work, we calibrate the infiltration parameters for both Horton and Green-Ampt models under flat ponded soil conditions. Then, by means of synthetic test cases, we perform a space-distributed sensitivity analysis in order to show that this calibration can be significantly affected by the introduction of topography or rainfall. In the second part, parameter calibration for a real catchment is addressed by comparing the numerical simulations with two different sets of experimental data, corresponding to very different events in terms of the rainfall volume. We show that the initial conditions of the catchment and the rainfall pattern have a special relevance in the quality of the adjustment. Hence, it is shown that the topography of the catchment and the storm characteristics affect the calibration of infiltration parameters.
Faudot, E.; Heuraux, S.; Colas, L.
2005-09-26
Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a 'test map' having initially a Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude {phi}0 (normalized to a characteristic length for transverse transport and to the local temperature). A 'peaking factor' is built from the DC peak potential normalized to {phi}0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the 'peaking factor' for ITER will be presented for a given configuration.
NASA Astrophysics Data System (ADS)
Guillamon, I.; Vieira, S.; Suderow, H.; Cordoba, R.; Sese, J.; de Teresa, J. M.; Ibarra, R.
In two dimensional (2D) systems, theory has proposed that random disorder destroys long range correlations driving a transition to a glassy state. Here, I will discuss new insights into this issue obtained through the direct visualization of the critical behaviour of a 2D superconducting vortex lattice formed in a thin film with a smooth 1D thickness modulation. Using scanning tunneling microscopy at 0.1K, we have tracked the modification in the 2D vortex arrangements induced by the 1D thickness modulation while increasing the vortex density by three orders of magnitude. Upon increasing the field, we observed a two-step order-disorder transition in the 2D vortex lattice mediated by the appearance of dislocations and disclinations and accompanied by an increase in the local vortex density fluctuations. Through a detailed analysis of correlation functions, we find that the transition is driven by the incommensurate 1D thickness modulation. We calculate the critical points and exponents and find that they are well above theoretical expectation for random disorder. Our results show that long range 1D correlations in random potentials enhance the stability range of the ordered phase in a 2D vortex lattice. Work supported by Spanish MINECO, CIG Marie Curie Grant, Axa Research Fund and FBBVA.
Buechler, H. P.; Micheli, A.; Pupillo, G.; Zoller, P.; Demler, E.; Lukin, M.; Prokof'ev, N.
2007-02-09
We discuss techniques to tune and shape the long-range part of the interaction potentials in quantum gases of bosonic polar molecules by dressing rotational excitations with static and microwave fields. This provides a novel tool towards engineering strongly correlated quantum phases in combination with low-dimensional trapping geometries. As an illustration, we discuss the 2D superfluid-crystal quantum phase transition for polar molecules interacting via an electric-field-induced dipole-dipole potential.
NASA Astrophysics Data System (ADS)
Szerszeń, Krzysztof; Zieniuk, Eugeniusz
2016-06-01
The paper presents a strategy for numerical solving of parametric integral equation system (PIES) for 2D potential problems without explicit calculation of singular integrals. The values of these integrals will be expressed indirectly in terms of easy to compute non-singular integrals. The effectiveness of the proposed strategy is investigated with the example of potential problem modeled by the Laplace equation. The strategy simplifies the structure of the program with good the accuracy of the obtained solutions.
A subunit-selective potentiator of NR2C- and NR2D-containing NMDA receptors
Mullasseril, Praseeda; Hansen, Kasper B.; Vance, Katie M.; Ogden, Kevin K.; Yuan, Hongjie; Kurtkaya, Natalie L.; Santangelo, Rose; Orr, Anna G.; Le, Phuong; Vellano, Kimberly M.; Liotta, Dennis C.; Traynelis, Stephen F.
2011-01-01
NMDA receptors are tetrameric complexes of NR1 and NR2A-D subunits that mediate excitatory synaptic transmission and play a role in neurological disorders. We have identified a novel subunit-selective potentiator of NMDA receptors containing the NR2C or NR2D subunit, which could allow selective modification of circuit function in regions expressing NR2C/D subunits. The substituted tetrahydroisoquinoline CIQ enhances receptor responses two-fold with an EC50 of 3 μM by increasing channel opening frequency without altering mean open time or EC50 values for glutamate or glycine. The actions of CIQ depend on a single residue in the M1 region (NR2D Thr592) and the linker between the amino terminal domain and agonist binding domain. CIQ potentiates native NR2D-containing NMDA receptor currents from subthalamic neurons. Our identification of a subunit-selective NMDA receptor modulator reveals a new class of pharmacological tools with which to probe the role of NR2C- and NR2D-containing NMDA receptors in brain function and disease. PMID:20981015
Correct folding of an α-helix and a β-hairpin using a polarized 2D torsional potential.
Gao, Ya; Li, Yongxiu; Mou, Lirong; Lin, Bingbing; Zhang, John Z H; Mei, Ye
2015-01-01
A new modification to the AMBER force field that incorporates the coupled two-dimensional main chain torsion energy has been evaluated for the balanced representation of secondary structures. In this modified AMBER force field (AMBER03(2D)), the main chain torsion energy is represented by 2-dimensional Fourier expansions with parameters fitted to the potential energy surface generated by high-level quantum mechanical calculations of small peptides in solution. Molecular dynamics simulations are performed to study the folding of two model peptides adopting either α-helix or β-hairpin structures. Both peptides are successfully folded into their native structures using an AMBER03(2D) force field with the implementation of a polarization scheme (AMBER03(2D)p). For comparison, simulations using a standard AMBER03 force field with and without polarization, as well as AMBER03(2D) without polarization, fail to fold both peptides successfully. The correction to secondary structure propensity in the AMBER03 force field and the polarization effect are critical to folding Trpzip2; without these factors, a helical structure is obtained. This study strongly suggests that this new force field is capable of providing a more balanced preference for helical and extended conformations. The electrostatic polarization effect is shown to be indispensable to the growth of secondary structures. PMID:26039188
Oinonen, Kirsten A
2009-06-01
Many women experience emotional or physical side effects when taking oral contraceptives (OCs). Despite the potential impact on women's health and well-being, there are no valid methods to screen women for their risk of OC side effects. The present paper presents the results of two studies where anthropometric indicators of androgen exposure, 2D:4D and middle-phalangeal hair, were examined for their potential as predictors of OC side effects. In study 1, 2D:4D was associated with women's reports of a history of: (a) negative mood side effects; (b) discontinuation due to negative mood side effects; (c) specific mood side effects (i.e., crying, sadness, and altered trust in one's partners) and (d) specific physical side effects (i.e., headaches, fatigue, and decreased sex drive). In study 2, 2D:4D and/or middle-phalangeal hair was/were associated with a reported history of: (a) discontinuation due to negative mood side effects; (b) specific mood-related side effects (i.e., negative mood, disrupted sleep, increased aggression, and altered trust in one's partner) and (c) specific physical side effects (i.e., headaches, decreased menstrual cramps, and increased sex drive/arousal). The general pattern was that adverse OC side effects were experienced by women with lower 2D:4D and fewer middle-phalangeal hairs. Almost all relationships remained significant when response bias was controlled. These results suggest a possible role for prenatal testosterone exposure and both androgen action and sensitivity in women's experience of OC side effects. Furthermore, these two digit measures may be useful predictors of hormonal contraceptive side effects in women. PMID:19131172
A 2D forward and inverse code for streaming potential problems
NASA Astrophysics Data System (ADS)
Soueid Ahmed, A.; Jardani, A.; Revil, A.
2013-12-01
The self-potential method corresponds to the passive measurement of the electrical field in response to the occurrence of natural sources of current in the ground. One of these sources corresponds to the streaming current associated with the flow of the groundwater. We can therefore apply the self- potential method to recover non-intrusively some information regarding the groundwater flow. We first solve the forward problem starting with the solution of the groundwater flow problem, then computing the source current density, and finally solving a Poisson equation for the electrical potential. We use the finite-element method to solve the relevant partial differential equations. In order to reduce the number of (petrophysical) model parameters required to solve the forward problem, we introduced an effective charge density tensor of the pore water, which can be determined directly from the permeability tensor for neutral pore waters. The second aspect of our work concerns the inversion of the self-potential data using Tikhonov regularization with smoothness and weighting depth constraints. This approach accounts for the distribution of the electrical resistivity, which can be independently and approximately determined from electrical resistivity tomography. A numerical code, SP2DINV, has been implemented in Matlab to perform both the forward and inverse modeling. Three synthetic case studies are discussed.
SP2DINV: A 2D forward and inverse code for streaming potential problems
NASA Astrophysics Data System (ADS)
Soueid Ahmed, A.; Jardani, A.; Revil, A.; Dupont, J. P.
2013-09-01
The self-potential method corresponds to the passive measurement of the electrical field in response to the occurrence of natural sources of current in the ground. One of these sources corresponds to the streaming current associated with the flow of the ground water. We can therefore apply the self-potential method to recover non-intrusively some information regarding the ground water flow. We first solve the forward problem starting with the solution of the ground water flow problem, then computing the source current density, and finally solving a Poisson equation for the electrical potential. We use the finite-element method to solve the relevant partial differential equations. In order to reduce the number of (petrophysical) model parameters required to solve the forward problem, we introduced an effective charge density tensor of the pore water, which can be determined directly from the permeability tensor for neutral pore waters. The second aspect of our work concerns the inversion of the self-potential data using Tikhonov regularization with smoothness and weighting depth constraints. This approach accounts for the distribution of the electrical resistivity, which can be independently and approximately determined from electrical resistivity tomography. A numerical code, SP2DINV, has been implemented in Matlab to perform both the forward and inverse modeling. Three synthetic case studies are discussed.
Potential energy landscapes for the 2D XY model: Minima, transition states, and pathways
NASA Astrophysics Data System (ADS)
Mehta, Dhagash; Hughes, Ciaran; Schröck, Mario; Wales, David J.
2013-11-01
We describe a numerical study of the potential energy landscape for the two-dimensional XY model (with no disorder), considering up to 100 spins and central processing unit and graphics processing unit implementations of local optimization, focusing on minima and saddles of index one (transition states). We examine both periodic and anti-periodic boundary conditions, and show that the number of stationary points located increases exponentially with increasing lattice size. The corresponding disconnectivity graphs exhibit funneled landscapes; the global minima are readily located because they exhibit relatively large basins of attraction compared to the higher energy minima as the lattice size increases.
Magneto-elastic coupling in a potential ferromagnetic 2D atomic crystal
NASA Astrophysics Data System (ADS)
Tian, Yao; Gray, Mason J.; Ji, Huiwen; Cava, R. J.; Burch, Kenneth S.
2016-06-01
Cr2Ge2Te6 has been of interest for decades, as it is one of only a few naturally forming ferromagnetic semiconductors. Recently, this material has been revisited due to its potential as a two-dimensional semiconducting ferromagnet and a substrate to induce anomalous quantum Hall states in topological insulators. However, many relevant properties of Cr2Ge2Te6 still remain poorly understood, especially the spin-phonon coupling crucial to spintronic, multiferrioc, thermal conductivity, magnetic proximity and the establishment of long range order on the nanoscale. We explore the interplay between the lattice and magnetism through high resolution micro-Raman scattering measurements over the temperature range from 10 to 325 K. Strong spin-phonon coupling effects are confirmed from multiple aspects: two low energy modes splits in the ferromagnetic phase, magnetic quasielastic scattering in the paramagnetic phase, the phonon energies of three modes show clear upturn below T C, and the phonon linewidths change dramatically below T C as well. Our results provide the first demonstration of spin-phonon coupling in a potential two-dimensional atomic crystal.
Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.
Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir
2012-01-01
Cerebral activation and autonomic nervous system have importance in studies such as mental stress. The aim of this study is to analyze variations in EEG scalp potential which may influence autonomic activation of heart while playing video games. Ten healthy participants were recruited in this study. Electroencephalogram (EEG) and electrocardiogram (ECG) signals were measured simultaneously during playing video game and rest conditions. Sympathetic and parasympathetic innervations of heart were evaluated from heart rate variability (HRV), derived from the ECG. Scalp potential was measured by the EEG. The results showed a significant upsurge in the value theta Fz/alpha Pz (p<0.001) while playing game. The results also showed tachycardia while playing video game as compared to rest condition (p<0.005). Normalized low frequency power and ratio of low frequency/high frequency power were significantly increased while playing video game and normalized high frequency power sank during video games. Results showed synchronized activity of cerebellum and sympathetic and parasympathetic innervation of heart. PMID:23366661
Weakly coupled bound state of 2-D Schrödinger operator with potential-measure
Kondej, Sylwia; Lotoreichik, Vladimir
2014-01-01
We consider a self-adjoint two-dimensional Schrödinger operator Hαμ, which corresponds to the formal differential expression−Δ−αμ, where μ is a finite compactly supported positive Radon measure on R2 from the generalized Kato class and α>0 is the coupling constant. It was proven earlier that σess(Hαμ)=[0,+∞). We show that for sufficiently small α the condition ♯σd(Hαμ)=1 holds and that the corresponding unique eigenvalue has the asymptotic expansionλ(α)=−(Cμ+o(1))exp(−4παμ(R2)),α→0+, with a certain constant Cμ>0. We also obtain a formula for the computation of Cμ. The asymptotic expansion of the corresponding eigenfunction is provided. The statements of this paper extend the results of Simon [41] to the case of potentials-measures. Also for regular potentials our results are partially new. PMID:25843975
Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.
Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir
2012-01-01
Cerebral activation and autonomic nervous system have importance in studies such as mental stress. The aim of this study is to analyze variations in EEG scalp potential which may influence autonomic activation of heart while playing video games. Ten healthy participants were recruited in this study. Electroencephalogram (EEG) and electrocardiogram (ECG) signals were measured simultaneously during playing video game and rest conditions. Sympathetic and parasympathetic innervations of heart were evaluated from heart rate variability (HRV), derived from the ECG. Scalp potential was measured by the EEG. The results showed a significant upsurge in the value theta Fz/alpha Pz (p<0.001) while playing game. The results also showed tachycardia while playing video game as compared to rest condition (p<0.005). Normalized low frequency power and ratio of low frequency/high frequency power were significantly increased while playing video game and normalized high frequency power sank during video games. Results showed synchronized activity of cerebellum and sympathetic and parasympathetic innervation of heart.
NASA Astrophysics Data System (ADS)
Sourbier, Florent; Operto, Stéphane; Virieux, Jean; Amestoy, Patrick; L'Excellent, Jean-Yves
2009-03-01
This is the first paper in a two-part series that describes a massively parallel code that performs 2D frequency-domain full-waveform inversion of wide-aperture seismic data for imaging complex structures. Full-waveform inversion methods, namely quantitative seismic imaging methods based on the resolution of the full wave equation, are computationally expensive. Therefore, designing efficient algorithms which take advantage of parallel computing facilities is critical for the appraisal of these approaches when applied to representative case studies and for further improvements. Full-waveform modelling requires the resolution of a large sparse system of linear equations which is performed with the massively parallel direct solver MUMPS for efficient multiple-shot simulations. Efficiency of the multiple-shot solution phase (forward/backward substitutions) is improved by using the BLAS3 library. The inverse problem relies on a classic local optimization approach implemented with a gradient method. The direct solver returns the multiple-shot wavefield solutions distributed over the processors according to a domain decomposition driven by the distribution of the LU factors. The domain decomposition of the wavefield solutions is used to compute in parallel the gradient of the objective function and the diagonal Hessian, this latter providing a suitable scaling of the gradient. The algorithm allows one to test different strategies for multiscale frequency inversion ranging from successive mono-frequency inversion to simultaneous multifrequency inversion. These different inversion strategies will be illustrated in the following companion paper. The parallel efficiency and the scalability of the code will also be quantified.
NASA Astrophysics Data System (ADS)
Bernauer, F.; Hürkamp, K.; Rühm, W.; Tschiersch, J.
2015-03-01
Detailed characterization and classification of precipitation is an important task in atmospheric research. Line scanning 2-D-video disdrometer technique is well established for rain observations. The two orthogonal views taken of each hydrometeor passing the sensitive area of the instrument qualify this technique especially for detailed characterization of non symmetric solid hydrometeors. However, in case of solid precipitation problems related to the matching algorithm have to be considered and the user must be aware of the limited spacial resolution when size and shape descriptors are analyzed. This work has the aim of clarifying the potential of 2-D-video disdrometer technique in deriving size, velocity and shape parameters from single recorded pictures. The need of implementing a matching algorithm suitable for mixed and solid phase precipitation is highlighted as an essential step in data evaluation. For this purpose simple reproducible experiments with solid steel spheres and irregularly shaped styrofoam particles are conducted. Self-consistency of shape parameter measurements is tested in 40 cases of real snow fall. As result it was found, that reliable size and shape characterization with a relative standard deviation of less than 5% is only possible for particles larger than 1 mm. For particles between 0.5 and 1.0 mm the relative standard deviation can grow up to 22% for the volume, 17% for size parameters and 14% for shape descriptors. Testing the adapted matching algorithm with a reproducible experiment with styrofoam particles a mismatch probability of less than 2.5% was found. For shape parameter measurements in case of real solid phase precipitation the 2DVD shows self-consistent behavior.
NASA Astrophysics Data System (ADS)
Dagnino, D.; Sallarès, V.; Biescas, B.; Ranero, C. R.
2016-08-01
This work demonstrates the feasibility of 2-D time-domain, adjoint-state acoustic full-waveform inversion (FWI) to retrieve high-resolution models of ocean physical parameters such as sound speed, temperature and salinity. The proposed method is first described and then applied to prestack multichannel seismic (MCS) data acquired in the Gulf of Cadiz (SW Iberia) in 2007 in the framework of the Geophysical Oceanography project. The inversion strategy flow includes specifically designed data preconditioning for acoustic noise reduction, followed by the inversion of sound speed in the shotgather domain. We show that the final sound speed model has a horizontal resolution of ˜ 70 m, which is two orders of magnitude better than that of the initial model constructed with coincident eXpendable Bathy Thermograph (XBT) data, and close to the theoretical resolution of O(λ). Temperature (T) and salinity (S) are retrieved with the same lateral resolution as sound speed by combining the inverted sound speed model with the thermodynamic equation of seawater and a local, depth-dependent T-S relation derived from regional conductivity-temperature-depth (CTD) measurements of the National Oceanic and Atmospheric Administration (NOAA) database. The comparison of the inverted T and S models with XBT and CTD casts deployed simultaneously to the MCS acquisition shows that the thermohaline contrasts are resolved with an accuracy of 0.18oC for temperature and 0.08 PSU for salinity. The combination of oceanographic and MCS data into a common, pseudo-automatic inversion scheme allows to quantitatively resolve submeso-scale features that ought to be incorporated into larger-scale ocean models of oceans structure and circulation.
Geisler, Cordelia; Gaisa, Nadine T.; Pfister, David; Fuessel, Susanne; Kristiansen, Glen; Braunschweig, Till; Gostek, Sonja; Beine, Birte; Diehl, Hanna C.; Jackson, Angela M.; Borchers, Christoph H.; Heidenreich, Axel; Meyer, Helmut E.; Knüchel, Ruth; Henkel, Corinna
2015-01-01
This study was designed to identify and validate potential new biomarkers for prostate cancer and to distinguish patients with and without biochemical relapse. Prostate tissue samples analyzed by 2D-DIGE (two-dimensional difference in gel electrophoresis) and mass spectrometry (MS) revealed downregulation of secernin-1 (P < 0.044) in prostate cancer, while vinculin showed significant upregulation (P < 0.001). Secernin-1 overexpression in prostate tissue was validated using Western blot and immunohistochemistry while vinculin expression was validated using immunohistochemistry. These findings indicate that secernin-1 and vinculin are potential new tissue biomarkers for prostate cancer diagnosis and prognosis, respectively. For validation, protein levels in urine were also examined by Western blot analysis. Urinary vinculin levels in prostate cancer patients were significantly higher than in urine from nontumor patients (P = 0.006). Using multiple reaction monitoring-MS (MRM-MS) analysis, prostatic acid phosphatase (PAP) showed significant higher levels in the urine of prostate cancer patients compared to controls (P = 0.012), while galectin-3 showed significant lower levels in the urine of prostate cancer patients with biochemical relapse, compared to those without relapse (P = 0.017). Three proteins were successfully differentiated between patients with and without prostate cancer and patients with and without relapse by using MRM. Thus, this technique shows promise for implementation as a noninvasive clinical diagnostic technique. PMID:25667921
Are the Animal Welfare Acts achieving their full potential?
2016-07-30
A decade has passed since the Animal Welfare Act 2006 and the Animal Health and Welfare (Scotland) Act 2006 became law. A session at this year's Animal Welfare Foundation Discussion Forum examined the successes and limitations of the Acts and whether they are working to their full potential. Further discussions centred on the keeping of non-traditional companion animals as pets and whether greater regulation of the pet trade is needed. Laura Honey reports. PMID:27474055
Are the Animal Welfare Acts achieving their full potential?
2016-07-30
A decade has passed since the Animal Welfare Act 2006 and the Animal Health and Welfare (Scotland) Act 2006 became law. A session at this year's Animal Welfare Foundation Discussion Forum examined the successes and limitations of the Acts and whether they are working to their full potential. Further discussions centred on the keeping of non-traditional companion animals as pets and whether greater regulation of the pet trade is needed. Laura Honey reports.
NASA Astrophysics Data System (ADS)
Savoini, P.; Lembege, B.
2014-12-01
The ion foreshock located upstream of the Earth's bow shock is populated with ions reflected back by the shock front. In-situ spacecraft measurements have clearly established the existence of two distinct populations in the upstream of the quasi-perpendicular shock region (i.e. for 45o ≤ ΘBn≤ 90o, where ΘBn is the angle between the shock normal and the upstream magnetostatic field): (i) field-aligned ion beams (or 'FAB') characterized by a gyrotropic distribution, and (ii) gyro-phase bunched ions (or 'GPB') characterized by a NON gyrotropic distribution, which exhibits a non-vanishing perpendicular bulk velocity. The use of 2D PIC simulations where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described, has evidenced that the shock front itself can be the possible source of these two characteristic populations. A recent analysis has evidenced that both populations can be discriminated in terms of interaction time (Δtinter) with the shock front. 'GPB' and 'FAB' populations are characterized by a short (Δtinter ~ 1 τci) and much larger (Δtinter ≥ 2 τci) interaction time respectively, where τci is the ion upstream gyroperiod. In addition, present statistical results evidence that: (i) backstreaming ions are splitted into 'FAB' and 'GPB' populations depending on their injection angle when hitting the shock front (defined between the local normal to the shock front and the gyration velocity vector). (ii) As a consequence, ion trajectories strongly differ between the 'FAB' and 'GPB' populations at the shock front. In particular, 'FAB' ions suffer multi-bounces along the curved front whereas 'GPB' ions make only one bounce. Such differences may explain why the 'FAB' population loses their gyro-phase coherency and become gyrotropic which is not the case for the 'GPB'. Then, the differences observed between 'FAB' and 'GPB' populations do not involve some distinct reflection processes as often claimed in the
NASA Astrophysics Data System (ADS)
Sourbier, F.; Operto, S.; Virieux, J.
2006-12-01
We present a distributed-memory parallel algorithm for 2D visco-acoustic full-waveform inversion of wide-angle seismic data. Our code is written in fortran90 and use MPI for parallelism. The algorithm was applied to real wide-angle data set recorded by 100 OBSs with a 1-km spacing in the eastern-Nankai trough (Japan) to image the deep structure of the subduction zone. Full-waveform inversion is applied sequentially to discrete frequencies by proceeding from the low to the high frequencies. The inverse problem is solved with a classic gradient method. Full-waveform modeling is performed with a frequency-domain finite-difference method. In the frequency-domain, solving the wave equation requires resolution of a large unsymmetric system of linear equations. We use the massively parallel direct solver MUMPS (http://www.enseeiht.fr/irit/apo/MUMPS) for distributed-memory computer to solve this system. The MUMPS solver is based on a multifrontal method for the parallel factorization. The MUMPS algorithm is subdivided in 3 main steps: a symbolic analysis step that performs re-ordering of the matrix coefficients to minimize the fill-in of the matrix during the subsequent factorization and an estimation of the assembly tree of the matrix. Second, the factorization is performed with dynamic scheduling to accomodate numerical pivoting and provides the LU factors distributed over all the processors. Third, the resolution is performed for multiple sources. To compute the gradient of the cost function, 2 simulations per shot are required (one to compute the forward wavefield and one to back-propagate residuals). The multi-source resolutions can be performed in parallel with MUMPS. In the end, each processor stores in core a sub-domain of all the solutions. These distributed solutions can be exploited to compute in parallel the gradient of the cost function. Since the gradient of the cost function is a weighted stack of the shot and residual solutions of MUMPS, each processor
Li, Changtian; Zhang, Changsheng; Li, Junlai; Cao, Xiaolin; Song, Danfei
2016-07-01
2-D Shear wave elastography (SWE) imaging is widely used in clinical practice, and some researchers have applied this technique in the evaluation of neonatal brains. However, the immediate and long-term impacts of dynamic radiation force exposure on the neonatal central nervous system remain unknown. In this study, we exposed neonatal mice to 2-D SWE scanning for 10 min, 20 min and 30 min under diagnostic mode (mechanical index [MI]: 1.3; thermal index [TI]: 0.5), respectively. For the control group, the neonatal mice were sham irradiated for 30 min with the machine powered off. Their brains were collected and analyzed using histologic staining and western blot analysis at 24 h and 3 mo after the 2-D SWE scanning. The Morris water maze (MWM) test was used to assess learning and memory function of the mice at 3 mo of age. The results indicated that using 2-D SWE in evaluating brains of neonatal mice does not cause detectable histologic changes, nor does it have long-term effects on their learning and memory abilities. However, the PI3 K/AKT/mTOR pathway was disturbed when the 2-D SWE scanning lasted for more than 30 min, and the expression of p-PKCa was suppressed by 10 min or more in 2-D SWE scanning. Although these injuries may be self-repaired as the mice grow, more attention should be paid to the scanning duration when applying 2-D-SWE elastography in the assessment of neonatal brains.
Delaporte, E; Slaughter, D E; Egan, M A; Gatto, G J; Santos, A; Shelley, J; Price, E; Howells, L; Dean, D C; Rodrigues, A D
2001-08-01
High throughput inhibition screens for human cytochrome P450s (CYPs) are being used in preclinical drug metabolism to support drug discovery programs. The versatility of scintillation proximity assay (SPA) technology has enabled the development of a homogeneous high throughput assay for cytochrome P450 2D6 (CYP2D6) inhibition screen using [O-methyl-(14)C]dextromethorphan as substrate. The basis of the assay was the trapping of the O-demethylation product, [(14)C]HCHO, on SPA beads. Enzyme kinetics parameters V(max) and apparent K(m), determined using pooled human liver microsomes and microsomes from baculovirus cells coexpressing human CYP2D6 and NADPH-cytochrome P450 reductase, were 245 pmol [(14)C]HCHO/min/mg protein and 11 microM, and 27 pmol [(14)C]HCHO/min/pmol and 1.6 microM, respectively. In incubations containing either pooled microsomes or recombinant CYP2D6, [(14)C]dextromethorphan O-demethylase activity was inhibited in the presence of quinidine (IC(50) = 1.0 microM and 20 nM, respectively). By comparison, inhibitors selective for other CYP isoforms were relatively weak (IC(50) > 25 microM). In agreement, a selective CYP2D6 inhibitory monoclonal antibody caused greater than 90% inhibition of [(14)C]dextromethorphan O-demethylase activity in human liver microsomes, whereas CYP2C9/19- and CYP3A4/5-selective antibodies elicited a minimal inhibitory effect. SPA-based [(14)C]dextromethorphan O-demethylase activity was also shown to correlate (r(2) = 0.6) with dextromethorphan O-demethylase measured by high-performance liquid chromatography in a bank of human liver microsomes (N = 15 different organ donors). In a series of known CYP2D6 inhibitors/substrates, the SPA-based assay resolved potent inhibitors (IC(50) < 2 microM) from weak inhibitors (IC(50) >or= 20 microM). It is concluded that the SPA-based assay described herein is suitable for CYP2D6 inhibition screening using either native human liver microsomes or cDNA-expressed CYP2D6. PMID:11689122
A Molecular Full-Potential LMTO Calculation for Copper Clusters
NASA Astrophysics Data System (ADS)
Datta, Radhika Prosad; Banerjea, Amitava; Mookerjee, Abhijit; Bhattacharyya, A. K.
We study the electronic properties of small (10-20 atoms) copper clusters using the newly-developed molecular full-potential linearized muffin-tin orbital two-centre-fit (TCF) method of Methfessel and van Schilfgaarde. The geometric structures of the clusters had earlier been determined by us through simulated annealing using the Equivalent Crystal Theory to compute total energies. We report the variation of the binding energy, as obtained from the TCF calculations, with cluster size and compare these to the binding energies determined, for the same structures, from the ECT. We also show the variation of the HOMO-LUMO gap with cluster size, and the pseudo-density of states for select cluster sizes.
On Approximate Factorization Schemes for Solving the Full Potential Equation
NASA Technical Reports Server (NTRS)
Holst, Terry L.
1997-01-01
An approximate factorization scheme based on the AF2 algorithm is presented for solving the three-dimensional full potential equation for the transonic flow about isolated wings. Two spatial discretization variations are presented, one using a hybrid first-order/second-order-accurate scheme and the second using a fully second-order-accurate scheme. The present algorithm utilizes a C-H grid topology to map the flow field about the wing. One version of the AF2 iteration scheme is used on the upper wing surface and another slightly modified version is used on the lower surface. These two algorithm variations are then connected at the wing leading edge using a local iteration technique. The resulting scheme has improved linear stability characteristics and improved time-like damping characteristics relative to previous implementations of the AF2 algorithm. The presentation is highlighted with a grid refinement study and a number of numerical results.
ERIC Educational Resources Information Center
Lackovic, Natasa; Crook, Charles; Cobb, Sue; Shalloe, Sally; D'Cruz, Mirabelle
2015-01-01
Background: There is much to be realised in the educational potential of national and world heritage sites. Such sites need to be supported in sharing their resources with a wide and international public, especially within formal education. Two-dimensional (2D) and three-dimensional (3D) heritage site visualisations could serve this need. Our…
A fast, time-accurate unsteady full potential scheme
NASA Technical Reports Server (NTRS)
Shankar, V.; Ide, H.; Gorski, J.; Osher, S.
1985-01-01
The unsteady form of the full potential equation is solved in conservation form by an implicit method based on approximate factorization. At each time level, internal Newton iterations are performed to achieve time accuracy and computational efficiency. A local time linearization procedure is introduced to provide a good initial guess for the Newton iteration. A novel flux-biasing technique is applied to generate proper forms of the artificial viscosity to treat hyperbolic regions with shocks and sonic lines present. The wake is properly modeled by accounting not only for jumps in phi, but also for jumps in higher derivatives of phi, obtained by imposing the density to be continuous across the wake. The far field is modeled using the Riemann invariants to simulate nonreflecting boundary conditions. The resulting unsteady method performs well which, even at low reduced frequency levels of 0.1 or less, requires fewer than 100 time steps per cycle at transonic Mach numbers. The code is fully vectorized for the CRAY-XMP and the VPS-32 computers.
NASA Technical Reports Server (NTRS)
Farrell, C.; Adamczyk, J.
1981-01-01
A reliable method is presented for calculating the flowfield about a cascade of arbitrary 2-D airfoils. The method approximates the three-dimensional flow in a turbomachinery blade row by correcting for streamtube convergence and radius change in the throughflow direction. The method is a fully conservative solution of the full potential equation incorporating the finite volume technique on a body-fitted periodic mesh, with an artificial density imposed in the transonic region to ensure stability and the capture of shock waves. Comparison of results for several supercritical blades shows good agreement with their hodograph solutions. Other calculations for these profiles as well as standard NACA blade sections indicate that this is a useful scheme for analyzing both the design and off-design performance of turbomachinery blading.
Design and synthesis of substituted pyrido[3,2-d]-1,2,3-triazines as potential Pim-1 inhibitors.
Fan, Yin-Bo; Li, Kun; Huang, Min; Cao, Yu; Li, Ying; Jin, Shu-Yu; Liu, Wen-Bing; Wen, Jia-Chen; Liu, Dan; Zhao, Lin-Xiang
2016-02-15
A novel series of substituted pyrido[3,2-d]-1,2,3-triazines were designed and synthesized as Pim-1 inhibitors through scaffold hopping. Most of the derivatives showed potent in vitro Pim-1 inhibitory activities and anti-proliferative effects toward prostate cancer cells. Among them, 6b, 6h and 6m showed the best Pim-1 inhibitory activity with IC50 values of 0.69, 0.60 and 0.80 μM, respectively. Furthermore, compounds 6b, 6i, 6j and 6m showed strong inhibitory activity to human prostate cancer LNcap and PC-3 cell lines with IC50 values at low micromolar level. Structure-activity relationship analysis revealed that appropriate substitutions at C-6 positions contributed to the kinase inhibition and antiproliferative effects. Moreover, western blot assay suggested that 6j could decrease the levels of p-BAD and p-4E-BP1 in a dose-dependent manner in PC-3 cells. Docking studies showed that 3-N of the scaffold formed a hydrogen bond with Lys67, aromatic 4-aniline formed a key π-π stack with Phe49. Taken together, this study might provide the first sight for developing the pyrido[3,2-d]-1,2,3-triazine scaffold as novel Pim-1 inhibitors.
Wake coupling to full potential rotor analysis code
NASA Technical Reports Server (NTRS)
Torres, Francisco J.; Chang, I-Chung; Oh, Byung K.
1990-01-01
The wake information from a helicopter forward flight code is coupled with two transonic potential rotor codes. The induced velocities for the near-, mid-, and far-wake geometries are extracted from a nonlinear rigid wake of a standard performance and analysis code. These, together with the corresponding inflow angles, computation points, and azimuth angles, are then incorporated into the transonic potential codes. The coupled codes can then provide an improved prediction of rotor blade loading at transonic speeds.
Sánchez-Iglesias, Santiago; García-Solaesa, Virginia; García-Berrocal, Belén; Sanchez-Martín, Almudena; Lorenzo-Romo, Carolina; Martín-Pinto, Tomás; Gaedigk, Andrea; González-Buitrago, José Manuel; Isidoro-García, María
2016-01-01
Abstract One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects. A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip CYP450 Test to analyzing 33 allelic variants of the CYP2D6 gene. All bipolar patients with poor metabolizer status showed maniac switching when CYP2D6 substrates such as selective serotonin reuptake inhibitors were prescribed. No specific patterns were identified for adverse events for other disorders. We propose to utilize pharmacogenetic testing as an intervention to aid in the identification of patients who are at risk of developing affective switching in bipolar disorder treated with selective serotonin reuptake inhibitors, CYP2D6 substrates, and inhibitors. PMID:26871771
Sánchez-Iglesias, Santiago; García-Solaesa, Virginia; García-Berrocal, Belén; Sanchez-Martín, Almudena; Lorenzo-Romo, Carolina; Martín-Pinto, Tomás; Gaedigk, Andrea; González-Buitrago, José Manuel; Isidoro-García, María
2016-02-01
One of the main concerns in psychiatric care is safety related to drug management. Pharmacogenetics provides an important tool to assess causes that may have contributed the adverse events during psychiatric therapy. This study illustrates the potential of pharmacogenetics to identify those patients for which pharmacogenetic-guided therapy could be appropriate. It aimed to investigate CYP2D6 genotype in our psychiatric population to assess the value of introducing pharmacogenetics as a primary improvement for predicting side effects.A broad series of 224 psychiatric patients comprising psychotic disorders, depressive disturbances, bipolar disorders, and anxiety disorders was included. The patients were genotyped with the AmpliChip CYP450 Test to analyzing 33 allelic variants of the CYP2D6 gene.All bipolar patients with poor metabolizer status showed maniac switching when CYP2D6 substrates such as selective serotonin reuptake inhibitors were prescribed. No specific patterns were identified for adverse events for other disorders.We propose to utilize pharmacogenetic testing as an intervention to aid in the identification of patients who are at risk of developing affective switching in bipolar disorder treated with selective serotonin reuptake inhibitors, CYP2D6 substrates, and inhibitors.
Full-potential modeling of blade-vortex interactions
NASA Technical Reports Server (NTRS)
Jones, H. E.; Caradonna, F. X.
1986-01-01
A comparison is made of four different models for predicting the unsteady loading induced by a vortex passing close to an airfoil. (1) The first model approximates the vortex effect as a change in the airfoil angle of attack. (2) The second model is related to the first but, instead of imposing only a constant velocity on the airfoil, the distributed effect of the vortex is computed and used. This is analogous to a lifting surface method. (3) The third model is to specify a branch cut discontinuity in the potential field. The vortex is modeled as a jump in potential across the branch cut, the edge of which represents the center of the vortex. (4) The fourth method models the vortex expressing the potential as the sum of a known potential due to the vortex and an unknown perturbation due to the airfoil. The purpose of the current study is to investigate the four vortex models described above and to determine their relative merits and suitability for use in large three-dimensional codes.
Syngeneic AAV pseudo-vectors potentiates full vector transduction
Technology Transfer Automated Retrieval System (TEKTRAN)
An excessive amount of empty capsids are generated during regular AAV vector production process. These pseudo-vectors often remain in final vectors used for animal studies or clinical trials. The potential effects of these pseudo-vectors on AAV transduction have been a major concern. In the current ...
Examining the Full Potential of the Extended School
ERIC Educational Resources Information Center
Orchard, Linda
2007-01-01
This paper describes a project aimed at helping children and their families achieve their potential. It is based in an area of high social disadvantage. The authors explain how parenting classes held at a community college (a comprehensive school with provision for adult education), have led to the development of a suite of courses leading to…
Ekama, G A; Marais, P
2004-02-01
The applicability of the one-dimensional idealized flux theory (1DFT) for the design of secondary settling tanks (SSTs) is evaluated by comparing its predicted maximum surface overflow (SOR) and solids loading (SLR) rates with that calculated with the two-dimensional computational fluid dynamics model SettlerCAD using as a basis 35 full-scale SST stress tests conducted on different SSTs with diameters from 30 to 45m and 2.25-4.1m side water depth (SWD), with and without Stamford baffles. From the simulations, a relatively consistent pattern appeared, i.e. that the 1DFT can be used for design but its predicted maximum SLR needs to be reduced by an appropriate flux rating, the magnitude of which depends mainly on SST depth and hydraulic loading rate (HLR). Simulations of the Watts et al. (Water Res. 30(9)(1996)2112) SST, with doubled SWDs and the Darvill new (4.1m) and old (2.5m) SSTs with interchanged depths, were run to confirm the sensitivity of the flux rating to depth and HLR. Simulations with and without a Stamford baffle were also performed. While the design of the internal features of the SST, such as baffling, has a marked influence on the effluent SS concentration while the SST is underloaded, these features appeared to have only a small influence on the flux rating, i.e. capacity, of the SST. Until more information is obtained, it would appear from the simulations that the flux rating of 0.80 of the 1DFT maximum SLR recommended by Ekama and Marais (Water Pollut. Control 85(1)(1986)101) remains a reasonable value to apply in the design of full-scale SSTs-for deep SSTs (4m SWD) the flux rating could be increased to 0.85 and for shallow SSTs (2.5m SWD) decreased to 0.75. It is recommended that (i) while the apparent interrelationship between SST flux rating and depth suggests some optimization of the volume of the SST, this be avoided and (ii) the depth of the SST be designed independently of the surface area as is usually the practice and once selected, the
NASA Astrophysics Data System (ADS)
Martin, T. P.; Schultz, A.
2012-12-01
understand the existing baseline subsurface resistivity structure at the Newberry site prior to well stimulation, magnetotelluric (MT) data will be collected in late July 2012 using two long period (1 Hz sampling) Narod Geophysics NIMS MT instruments along with EarthScope MT data aligned in a ~210 km long N-S profile centered on the stimulation zone. A 2-D inverse model will be obtained from the MT data set. The goal of this investigation is to determine the variations in the electrical resistivity in the mid-to-lower crust beneath the western flank of the caldera, providing a deeper view of putative heat sources than existing studies in this
NASA Astrophysics Data System (ADS)
Shulakova, V.
2015-12-01
The quantity of total organic carbon (TOC) and its type determine the ability of source rocks to generate hydrocarbons. Thus, the quantification of TOC content is an essential part of any reservoir characterisation project. Traditionally TOC is estimated from geochemical analysis of core samples. In this case the results are limited spatially by a well location as well as vertically by a number of tested samples. At the same time TOC vertical variability might be very high, changing every 1-3 m. The several methods have been deployed to estimate TOC from well-log data which provides continuous vertical profile estimations. The basin wide information might be provided by the utilization of seismic surveys. The methodology of mapping source rocks based on seismic data has been lately reported to be successful for the thick source rocks (>20 m) with relatively high TOC values up to 3-4% (Løseth et al., 2011). We employ the described approach and demonstrate our findings for a case study from Ceduna Basin (Great Australian Bight, Australia). The reported TOC values estimated from the cores go up to only 1.3%. The organic matter is contained in thin layers of claystones interlayered with sandstones. The workflow included TOC estimation from the well-log data and then seismic data inversion performed in JasonTM software. The inverted acoustic impedance decreases nonlinearly with increasing TOC content. The obtained results comprises 2D section of TOC distribution. The calculated TOC values are in a good agreement with the results of laboratory measurements. The results of this study show that TOC can be successfully estimated from seismic data inversion even in the case of low organic matter values. Further work has to be done to understand whether this approach works for different types of organic matter and stages of its maturation. Løseth H., Wensaas L., Gading M., Duffaut K., Springer M. 2001. Can hydrocarbon source rocks be identified on seismic data? Geology 39/12.
Vijayakumar, Thangavel Mahalingam; Kumar, Ramasamy Mohan; Agrawal, Aruna; Dubey, Govind Prasad; Ilango, Kaliappan
2015-07-01
Cytochrome P450 (CYP450) inhibition by the bioactive molecules of dietary supplements or herbal products leading to greater potential for toxicity of co-administered drugs. The present study was aimed to compare the inhibitory potential of selected common dietary bioactive molecules (Gallic acid, Ellagic acid, β-Sitosterol, Stigmasterol, Quercetin and Rutin) on CYP3A4 and CYP2D6 to assess safety through its inhibitory potency and to predict interaction potential with co-administered drugs. CYP450-CO complex assay was carried out for all the selected dietary bioactive molecules in isolated rat microsomes. CYP450 concentration of the rat liver microsome was found to be 0.474 nmol/mg protein, quercetin in DMSO has shown maximum inhibition on CYP450 (51.02 ± 1.24 %) but less when compared with positive control (79.02 ± 1.61 %). In high throughput fluorometric assay, IC50 value of quercetin (49.08 ± 1.02-54.36 ± 0.85 μg/ml) and gallic acid (78.46 ± 1.32-83.84 ± 1.06 μg/ml) was lower than other bioactive compounds on CYP3A4 and CYP2D6 respectively but it was higher than positive controls (06.28 ± 1.76-07.74 ± 1.32 μg/ml). In comparison of in vitro inhibitory potential on CYP3A4 and CYP2D6, consumption of food or herbal or dietary supplements containing quercetin and gallic acid without any limitation should be carefully considered when narrow therapeutic drugs are administered together. PMID:26139922
Schulz-Wendtland, R; Bani, M; Lux, M P; Schwab, S; Loehberg, C R; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Uder, M; Fasching, P A; Adamietz, B; Meier-Meitinger, M
2012-05-01
Purpose: Experimental study of a new system for digital 2D and 3D full-field mammography (FFDM) using a high resolution detector based on two shifts of a-Se. Material and Methods: Images were acquired using the new FFDM system Amulet® (FujiFilm, Tokio, Japan), an a-Se detector (receptor 24 × 30 cm(2), pixel size 50 µm, memory depth 12 bit, spatial resolution 10 lp/mm, DQE > 0.50). Integrated in the detector is a new method for data transfer, based on optical switch technology. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152A (Radiation Measurement Inc., Middleton, WI, USA) and the same parameters and exposure data (Tungsten, 100 mAs, 30 kV) were consistently used. We acquired 3 different pairs of images in the c-c and ml planes (2D) and in the c-c and c-c planes with an angle of 4 degrees (3D). Five radiologists experienced in mammography (experience ranging from 3 months to more than 5 years) analyzed the images (monitoring) which had been randomly encoded (random generator) with regard to the recognition of details such as specks of aluminum oxide (200-740 µm), nylon fibers (0.4-1.6 mm) and round lesions/masses (diameters 5-14 mm), using special linear glasses for 3D visualization, and compared the results. Results: A total of 225 correct positive decisions could be detected: we found 222 (98.7 %) correct positive results for 2D and 3D visualization in each case. Conclusion: The results of this phantom study showed the same detection rates for both 2D and 3D imaging using full field digital mammography. Our results must be confirmed in further clinical trials.
Vandamme, Anne-Mieke; Salemi, Marco; Van Brussel, Marianne; Liu, Hsin-Fu; Van Laethem, Kristel; Van Ranst, Marc; Michels, Ludovic; Desmyter, Jan; Goubau, Patrick
1998-01-01
We identified a potential new subtype within human T-cell lymphotropic virus type 2 (HTLV-2), HTLV-2d, present in members of an isolated Efe Bambuti Pygmy tribe. Two of 23 Efe Pygmies were HTLV-2 seropositive, with HTLV-2 Western blot and enzyme-linked immunosorbent assay reactivities. From one of them the entire genome of the HTLV-2 strain Efe2 could be amplified and sequenced. In all gene regions analyzed, this strain was the most divergent HTLV-2 strain, differing by 2.4% (tax/rex) to 10.7% (long terminal repeat) from both subtypes HTLV-2a and HTLV-2b, yet major functional elements are conserved. The similarity between the HTLV-2 Efe2 Gag and Env proteins and the corresponding HTLV-2a and -2b proteins is consistent with the observed serological reactivity. In the proximal pX region, one of the two alternative splice acceptor sites is abolished in HTLV-2 Efe2. Another interesting feature of this potential new subtype is that it has a Tax protein of 344 amino acids (aa), which is intermediate in length between the HTLV-2a Tax protein (331 aa) and the HTLV-2b and -2c Tax proteins (356 aa) and similar to the simian T-cell lymphotropic virus type 2 (STLV-2) PP1664 Tax protein. Together these two findings suggest a different phenotype for the HTLV-2 Efe2 strain. Phylogenetic analyses confirmed that the Pygmy Efe2 strain potentially belonged to a new and quite divergent subtype, HTLV-2d. When the STLV-2 bonobo viruses PP1664 and PanP were used as an outgroup, it was clear that the Pygmy HTLV-2 Efe2 strain had the longest independent evolution and that HTLV-2 evolution is consistent with an African origin. PMID:9557723
NASA Astrophysics Data System (ADS)
Evans, C. M.; Krynski, Kamil; Streeter, Zachary; Findley, G. L.
2015-12-01
We present for the first time the quasi-free electron energy V0(ρ) for H2, D2, and O2 from gas to liquid densities, on noncritical isotherms and on a near critical isotherm in each fluid. These data illustrate the ability of field enhanced photoemission (FEP) to determine V0(ρ) accurately in strongly absorbing fluids (e.g., O2) and fluids with extremely low critical temperatures (e.g., H2 and D2). We also show that the isotropic local Wigner-Seitz model for V0(ρ) — when coupled with thermodynamic data for the fluid — can yield optimized parameters for intermolecular potentials, as well as zero kinetic energy electron scattering lengths.
Rey, Michaël; Nikitin, Andrei V; Tyuterev, Vladimir G
2015-05-21
We report the variationally computed infrared spectrum of (12)CH2D2 using our recent potential energy and dipole moment methane surfaces, which have been initially derived in the irreducible tensor representation adapted to the tetrahedral symmetry of the major isotopologue (12)CH4. The nuclear motion calculations are accomplished by combining the normal-mode Eckart-Watson Hamiltonian with isotopic and symmetry transformations. Our direct vibrational calculations are compared to the 93 observed band centers up to 6300 cm(-1). Except for two outliers the root-mean-square deviation is 0.22 cm(-1) and the maximum error is 0.7 cm(-1) without empirical adjustment of parameters. The work aims at filling the gap concerning missing line strength information for this molecule. Theoretical spectra predictions are given up to J = 25 and, for the very first time, ab initio intensity predictions for rovibrational line transitions are in good qualitative agreement with available experimental spectra. PMID:25905903
NASA Astrophysics Data System (ADS)
Buchachenko, A. A.; Grinev, T. A.; Kłos, J.; Bieske, E. J.; Szczȩśniak, M. M.; Chałasiński, G.
2003-12-01
Three-dimensional potential energy and dipole moment surfaces of the Cl--H2 system are calculated ab initio by means of a coupled cluster method with single and double excitations and noniterative correction to triple excitations with augmented correlation consistent quadruple-zeta basis set supplemented with bond functions, and represented in analytical forms. Variational calculations of the energy levels up to the total angular momentum J=25 provide accurate estimations of the measured rotational spectroscopic constants of the ground van der Waals levels n=0 of the Cl-⋯H2/D2 complexes although they underestimate the red shifts of the mid-infrared spectra with v=0→v=1 vibrational excitation of the monomer. They also attest to the accuracy of effective radial interaction potentials extracted previously from experimental data using the rotational RKR procedure. Vibrational predissociation of the Cl-⋯H2/D2(v=1) complexes is shown to follow near-resonant vibrational-to-rotational energy transfer mechanism so that more than 97% of the product monomers are formed in the highest accessible rotational level. This mechanism explains the strong variation of the predissociation rate with isotopic content and nuclear spin form of the complex. Strong deviation of the observed relative abundances of ortho and para forms of the complexes from those of the monomers is qualitatively explained by the secondary ligand exchange reactions in the ionic beam, within the simple thermal equilibrium model. Positions and intensities of the hot v=0, n=1→v=1, n=1 and combination v=0, n=0→v=1, n=1 bands are predicted, and implications to the photoelectron spectroscopy of the complex are briefly discussed.
NASA Astrophysics Data System (ADS)
Biswas, A.; Sharma, S. P.
2012-12-01
best result without any ambiguity and smaller uncertainty. Keywords: SP anomaly, inclined sheet, 2D structure, forward problems, VFSA Optimization,
Campos, Fernando O.; Wiener, Thomas; Prassl, Anton J.; Ahammer, Helmut; Plank, Gernot; dos Santos, Rodrigo Weber; Sánchez-Quintana, Damián; Hofer, Ernst
2014-01-01
In experiments with cardiac tissue, local conduction is described by waveform analysis of the derivative of the extracellular potential Φ.e and by the loop morphology of the near-field strength E (the components of the electric field parallel and very close to the tissue surface). The question arises whether the features of these signals can be used to quantify the degree of fibrosis in the heart. A computer model allows us to study the behavior of electric signals at the endocardium with respect to known configurations of microstructure which can not be detected during the electrophysiological experiments. This work presents a 2D-computer model with sub-cellular resolution of atrial micro-conduction in the rabbit heart. It is based on the monodomain equations and digitized histographs from tissue slices obtained post-experimentum. It could be shown that excitation spread in densely coupled regions produces uniform and anisotropic conduction. In contrast, zones with parallel fibers separated by uncoupling interstitial space or connective tissue may show uniform or complex signals depending on pacing site. These results suggest that the analysis of Φ.e and E combined with multi-site pacing could be used to characterize the type and the size of fibrosis. PMID:21096441
NASA Astrophysics Data System (ADS)
Mazzini, A.; Husein, A.; Mauri, G.; Lupi, M.; Hadi, S.; Kemna, A.
2015-12-01
The Lusi mud eruption is located in the Sidoarjo area, Indonesia and is continuously erupting hot mud since its birth in May 2006. A comprehensive combined electrical resistivity and self-potential (SP) survey was performed in the 7 km2 area inside the Lusi embankment that had been built to contain the erupted mud and to prevent flooding of the surrounding roads and settlements. The goal of the geophysical survey is to map the near-surface occurrence of the Watukosek fault system, upon which LUSI resides, delineate its spatial pattern and monitor its development. We completed six lines of measurements combining resistivity measurement using Wenner configuration and SP measurements using roll-along technique. Three subparallel lines were located either to the north and to the south of the main crater. Each line was approximately W-E oriented extending for ~1.26 km. The surveyed regions consist of dried mud breccia (containing clayey-silty-sandy admixture with clast up to ~ 10 cm in size). The thickness of the dry walkable mud is approximately 2-3 m and the deeper layer consist of water saturated mud that could be vulnerable to a liquefaction scenario in case of significant seismic activity in the region. The resistivity data were inverted into 2-D resistivity images with a maximum exploration depth of almost 200 m. The resistivity images consistently reveal a region of about 300 m in width (between 30-90 m depth) characterized by anomalous resistivities, which are lower than the value observed in the surounding area. The position of these anomalies is also supported by the SP data, which suggests that their origin is related to fluid flow path in the subsurface. Thus the combined resistivity and SP results allow inference of an improved model of the Watukosek fault system.
NASA Astrophysics Data System (ADS)
Wang, Dong; Zhang, Qiaosheng; Li, Yue; Wang, Yiwen; Zhu, Junming; Zhang, Shaomin; Zheng, Xiaoxiang
2014-06-01
Objective. Many serious concerns exist in the long-term stability of brain-machine interfaces (BMIs) based on spike signals (single unit activity, SUA; multi unit activity, MUA). Some studies showed local field potentials (LFPs) could offer a stable decoding performance. However, the decoding stability of LFPs was examined only when high quality spike signals were recorded. Here we aim to examine the long-term decoding stability of LFPs over a larger time scale when the quality of spike signals was from good to poor or even no spike was recorded. Approach. Neural signals were collected from motor cortex of three monkeys via silicon arrays over 230, 290 and 690 days post-implantation when they performed 2D center out task. To compare long-term stability between LFPs and spike signals, we examined them in neural signals characteristics, directional tuning properties and offline decoding performance, respectively. Main results. We observed slow decreasing trends in the number of LFP channels recorded and mean LFP power in different frequency bands when spike signals quality decayed over time. The number of significantly directional tuning LFP channels decreased more slowly than that of tuning SUA and MUA. The variable preferred directions for the same signal features across sessions indicated non-stationarity of neural activity. We also found that LFPs achieved better decoding performance than SUA and MUA in retrained decoder when the quality of spike signals seriously decayed. Especially, when no spike was recorded in one monkey after 671 days post-implantation, LFPs still provided some kinematic information. In addition, LFPs outperformed MUA in long-term decoding stability in a static decoder. Significance. Our results suggested that LFPs were more durable and could provide better decoding performance when spike signals quality seriously decayed. It might be due to their resistance to recording degradation and their high redundancy among channels.
2005-07-01
Aniso2d is a two-dimensional seismic forward modeling code. The earth is parameterized by an X-Z plane in which the seismic properties Can have monoclinic with x-z plane symmetry. The program uses a user define time-domain wavelet to produce synthetic seismograms anrwhere within the two-dimensional media.
NASA Astrophysics Data System (ADS)
Jang, Hyun-Sook; Yu, Changqian; Hayes, Robert; Granick, Steve
2015-03-01
Polymer vesicles (``polymersomes'') are an intriguing class of soft materials, commonly used to encapsulate small molecules or particles. Here we reveal they can also effectively incorporate nanoparticles inside their polymer membrane, leading to novel ``2D nanocomposites.'' The embedded nanoparticles alter the capacity of the polymersomes to bend and to stretch upon external stimuli.
Neuschmelting, Volker; Burton, Neal C.; Lockau, Hannah; Urich, Alexander; Harmsen, Stefan; Ntziachristos, Vasilis; Kircher, Moritz F.
2015-01-01
A handheld approach to optoacoustic imaging is essential for the clinical translation. The first 2- and 3-dimensional handheld multispectral optoacoustic tomography (MSOT) probes featuring real-time unmixing have recently been developed. Imaging performance of both probes was determined in vitro and in a brain melanoma metastasis mouse model in vivo. T1-weighted MR images were acquired for anatomical reference. The limit of detection of melanoma cells in vitro was significantly lower using the 2D than the 3D probe. The signal decrease was more profound in relation to depth with the 3D versus the 2D probe. Both approaches were capable of imaging the melanoma tumors qualitatively at all time points. Quantitatively, the 2D approach enabled closer anatomical resemblance of the tumor compared to the 3D probe, particularly at depths beyond 3 mm. The 3D probe was shown to be superior for rapid 3D imaging and, thus, holds promise for more superficial target structures. PMID:27069872
Comparison of the full potential and Euler formulations for computing transonic airfoil flows
NASA Technical Reports Server (NTRS)
Flores, J.; Barton, J.; Holst, T. L.; Pulliam, T.
1984-01-01
A quantitative comparison between the Euler and full potential formulations with respect to speed and accuracy is presented. The robustness of the codes used is tested by a number of transonic airfoil cases. The computed results are from four transonic airfoil computer codes. The full potential codes use fully implicit iteration algorithms. The first Euler code uses a fully implicit ADI iteration scheme. The second Euler code uses an explicit Runge Kutta time stepping algorithm which is enhanced by a multigrid convergence acceleration scheme. Quantitative comparisons are made using various plots of lift coefficient versus the average mesh spacing along the airfoil. Besides yielding an asymptotic limit to the lift coefficient, these results also demonstrate the truncation error behavior of the various codes. Quantitative conclusions regarding the full potential and Euler formulations with respect to accuracy, speed, and robustness can be presented.
Numerical computation of transonic flow governed by the full-potential equation
NASA Technical Reports Server (NTRS)
Holst, T. L.
1983-01-01
Numerical solution techniques for solving transonic flow fields governed by the full potential equation are discussed. In a general sense relaxation schemes suitable for the numerical solution of elliptic partial differential equations are presented and discussed with emphasis on transonic flow applications. The presentation can be divided into two general categories: An introductory treatment of the basic concepts associated with the numerical solution of elliptic partial differential equations and a more advanced treatment of current procedures used to solve the full potential equation for transonic flow fields. The introductory material is presented for completeness and includes a brief introduction (Chapter 1), governing equations (Chapter 2), classical relaxation schemes (Chapter 3), and early concepts regarding transonic full potential equation algorithms (Chapter 4).
NASA Technical Reports Server (NTRS)
Toncich, S. S.; Collin, R. E.; Bhasin, K. B.
1993-01-01
A technique for a full wave characterization of microstrip open end discontinuities fabricated on uniaxial anisotropic substrates using potential theory is presented. The substrate to be analyzed is enclosed in a cutoff waveguide, with the anisotropic axis aligned perpendicular to the air-dielectric interface. A full description of the sources on the microstrip line is included with edge conditions built in. Extention to other discontinuities is discussed.
2011-12-31
Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j0) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assignsmore » an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations.« less
Inc., Geostellar,
2012-02-15
The WV Team will design and demonstrate a complete set of systems and processes for automating the identification of residential and light commercial solar opportunities, evaluating project finance options, securing permits and arranging for interconnections to the utility grid. These operations will be supported by the predictive qualification and feasibility of residential and light commercial solar energy opportunities in WV based on the current solar LCOE and potential state-wide policy initiatives. Through the WV Department of Commerce and its Division of Energy, the WV Team will coordinate with all 55 county development authorities in West Virginia, as well as a number of local and municipal authorities responsible for zoning and building code ordinances to support and implement a statewide, integrated set of regulations and administrative services. Additionally the WV Team will work with the State administration and legislature to develop incentives that will promote the financing of residential and light commercial solar projects.
A new consistent spatial differencing scheme for the transonic full-potential equation
NASA Technical Reports Server (NTRS)
Flores, J.; Holst, T. L.; Kwak, D.; Batiste, D. M.
1983-01-01
A new spatial differencing scheme for the transonic full-potential equation in conservative form has been developed. This scheme guarantees zero truncation error on any curvilinear mesh for freestream flows in either two- or three-space dimensions. Solutions obtained with this new differencing scheme, away from freestream regions, exhibit greatly improved accuracy, especially for nonsmooth or singular meshes.
How to Help Children with Learning Differences Reach Their Full Potential
ERIC Educational Resources Information Center
Lavoie, Theresa
2008-01-01
This article is the third part of a 10-part series that explores Attention Deficit Hyperactivity Disorder (ADHD). It offers and discusses tips on how to help children with learning differences reach their full potential. These include: (1) start with good nutrition; (2) be sure your child is exercising; (3) make sure your child is getting enough…
Numerical solution of the full potential equation using a chimera grid approach
NASA Technical Reports Server (NTRS)
Holst, Terry L.
1995-01-01
A numerical scheme utilizing a chimera zonal grid approach for solving the full potential equation in two spatial dimensions is described. Within each grid zone a fully-implicit approximate factorization scheme is used to advance the solution one interaction. This is followed by the explicit advance of all common zonal grid boundaries using a bilinear interpolation of the velocity potential. The presentation is highlighted with numerical results simulating the flow about a two-dimensional, nonlifting, circular cylinder. For this problem, the flow domain is divided into two parts: an inner portion covered by a polar grid and an outer portion covered by a Cartesian grid. Both incompressible and compressible (transonic) flow solutions are included. Comparisons made with an analytic solution as well as single grid results indicate that the chimera zonal grid approach is a viable technique for solving the full potential equation.
Relaxation and approximate factorization methods for the unsteady full potential equation
NASA Technical Reports Server (NTRS)
Shankar, V.; Ide, H.; Gorski, J.
1984-01-01
The unsteady form of the full potential equation is solved in conservation form, using implicit methods based on approximate factorization and relaxation schemes. A local time linearization for density is introduced to enable solution to the equation in terms of phi, the velocity potential. A novel flux-biasing technique is applied to generate proper forms of the artificial viscosity, to treat hyperbolic regions with shocks and sonic lines present. The wake is properly modeled by accounting not only for jumps in phi, but also for jumps in higher derivatives of phi obtained from requirements of density continuity. The far field is modeled using the Riemann invariants to simulate nonreflecting boundary conditions. Results are presented for flows over airfoils, cylinders, and spheres. Comparisons are made with available Euler and full potential results.
de Moraes, Natália V; Lauretti, Gabriela R; Coelho, Eduardo B; Godoy, Ana Leonor P C; Neves, Daniel V; Lanchote, Vera L
2016-04-01
The pharmacokinetics of tramadol is characterized by a large interindividual variability, which is partially attributed to polymorphic CYP2D6 metabolism. The contribution of CYP3A, CYP2B6, fraction unbound, and other potential covariates remains unknown. This study aimed to investigate the contribution of in vivo activities of cytochrome P450 (CYP) 2D6 and 3A as well as other potential covariates (CYP2B6 genotype to the SNP g.15631G>T, fraction unbound, age, body weight, creatinine clearance) to the enantioselective pharmacokinetics of tramadol. Thirty patients with neuropathic pain and phenotyped as CYP2D6 extensive metabolizers were treated with a single oral dose of 100 mg tramadol. Multiple linear regressions were performed to determine the contribution of CYP activities and other potential covariates to the clearance of tramadol enantiomers. The apparent total clearances were 44.9 (19.1-102-2) L/h and 55.2 (14.8-126.0) L/h for (+)- and (-)-tramadol, respectively [data presented as median (minimum-maximum)]. Between 79 and 83% of the overall variation in apparent clearance of tramadol enantiomers was explained by fraction unbound, CYP2D6, and CYP3A in vivo activities and body weight. Fraction unbound explained 47 and 41% of the variation in clearance of (+)-tramadol and (-)-tramadol, respectively. Individually, CYP2D6 and CYP3A activities were shown to have moderate contribution on clearance of tramadol enantiomers (11-16% and 11-18%, respectively). In conclusion, factors affecting fraction unbound of drugs (such as hyperglycemia or co-administration of drugs highly bound to plasma proteins) should be monitored, because this parameter dominates the elimination of tramadol enantiomers.
Quantitative 2D liquid-state NMR.
Giraudeau, Patrick
2014-06-01
Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.
A full-potential approach to the relativistic single-site Green’s function
NASA Astrophysics Data System (ADS)
Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Stocks, G. Malcolm
2016-09-01
One major purpose of studying the single-site scattering problem is to obtain the scattering matrices and differential equation solutions indispensable to multiple scattering theory (MST) calculations. On the other hand, the single-site scattering itself is also appealing because it reveals the physical environment experienced by electrons around the scattering center. In this paper we demonstrate a new formalism to calculate the relativistic full-potential single-site Green’s function. We implement this method to calculate the single-site density of states and electron charge densities. The code is rigorously tested and with the help of Krein’s theorem, the relativistic effects and full potential effects in group V elements and noble metals are thoroughly investigated.
Full potential methods for analysis/design of complex aerospace configurations
NASA Technical Reports Server (NTRS)
Shankar, Vijaya; Szema, Kuo-Yen; Bonner, Ellwood
1986-01-01
The steady form of the full potential equation, in conservative form, is employed to analyze and design a wide variety of complex aerodynamic shapes. The nonlinear method is based on the theory of characteristic signal propagation coupled with novel flux biasing concepts and body-fitted mapping procedures. The resulting codes are vectorized for the CRAY XMP and the VPS-32 supercomputers. Use of the full potential nonlinear theory is demonstrated for a single-point supersonic wing design and a multipoint design for transonic maneuver/supersonic cruise/maneuver conditions. Achievement of high aerodynamic efficiency through numerical design is verified by wind tunnel tests. Other studies reported include analyses of a canard/wing/nacelle fighter geometry.
A full-potential approach to the relativistic single-site Green's function.
Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Malcolm Stocks, G
2016-09-01
One major purpose of studying the single-site scattering problem is to obtain the scattering matrices and differential equation solutions indispensable to multiple scattering theory (MST) calculations. On the other hand, the single-site scattering itself is also appealing because it reveals the physical environment experienced by electrons around the scattering center. In this paper we demonstrate a new formalism to calculate the relativistic full-potential single-site Green's function. We implement this method to calculate the single-site density of states and electron charge densities. The code is rigorously tested and with the help of Krein's theorem, the relativistic effects and full potential effects in group V elements and noble metals are thoroughly investigated. PMID:27388858
NASA Technical Reports Server (NTRS)
Steger, J. L.; Caradonna, F. X.
1980-01-01
An implicit finite difference procedure is developed to solve the unsteady full potential equation in conservation law form. Computational efficiency is maintained by use of approximate factorization techniques. The numerical algorithm is first order in time and second order in space. A circulation model and difference equations are developed for lifting airfoils in unsteady flow; however, thin airfoil body boundary conditions have been used with stretching functions to simplify the development of the numerical algorithm.
Application of a Chimera Full Potential Algorithm for Solving Aerodynamic Problems
NASA Technical Reports Server (NTRS)
Holst, Terry L.; Kwak, Dochan (Technical Monitor)
1997-01-01
A numerical scheme utilizing a chimera zonal grid approach for solving the three dimensional full potential equation is described. Special emphasis is placed on describing the spatial differencing algorithm around the chimera interface. Results from two spatial discretization variations are presented; one using a hybrid first-order/second-order-accurate scheme and the second using a fully second-order-accurate scheme. The presentation is highlighted with a number of transonic wing flow field computations.
NASA Technical Reports Server (NTRS)
Nakamura, S.
1983-01-01
The effects of truncation error on the numerical solution of transonic flows using the full potential equation are studied. The effects of adapting grid point distributions to various solution aspects including shock waves is also discussed. A conclusion is that a rapid change of grid spacing is damaging to the accuracy of the flow solution. Therefore, in a solution adaptive grid application an optimal grid is obtained as a tradeoff between the amount of grid refinement and the rate of grid stretching.
NASA Astrophysics Data System (ADS)
Shugo Suzuki,; Hidehisa Ohta,
2010-07-01
We study the orbital, spin, and total magnetic moments in uranium monochalcogenides, UX where X=S, Se, and Te, using the fully relativistic full-potential calculations based on the spin density functional theory. In particular, the orbital magnetic moments are calculated with the Dirac current. We employ two methods which adopt distinctly different basis sets; one is the fully relativistic full-potential linear-combination-of-atomic-orbitals (FFLCAO) method and the other is the fully relativistic full-potential mixed-basis (FFMB) method. Showing that the orbital magnetic moments calculated using the FFLCAO method and those calculated using the FFMB method agree very well with each other, we demonstrate that, in contrast to the conventional method, the method with the Dirac current enables us to calculate the orbital magnetic moments even if the basis set includes basis functions with no definite angular momenta, e.g., the plane waves in the FFMB method. Furthermore, it is found that the orbital magnetic moments obtained in this work are larger by nearly 0.4 μB than those obtained using the conventional method. This is crucial because the resultant differences in the total magnetic moments are about 30%. We compare the results of this work with those of previous theoretical and experimental studies.
Li, Jiazhong; Li, Shuyan; Bai, Chongliang; Liu, Huanxiang; Gramatica, Paola
2013-07-01
Malaria is a fatal tropical and subtropical disease caused by the protozoal species Plasmodium. Many commonly available antimalarial drugs and therapies are becoming ineffective because of the emergence of multidrug resistant Plasmodium falciparum, which drives the need for the development of new antimalarial drugs. Recently, a series of 3-carboxyl-4(1H)-quinolone analogs, derived from the famous compound endochin, were reported as promising candidates for orally efficacious antimalarials. In this study, to analyze the structure-activity relationships (SAR) of these quinolones and investigate the structural requirements for antimalarial activity, the 2D multiple linear regressions (MLR) method and 3D comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods are employed to evolve different QSAR models. All these models give satisfactory results with highly accurate fitting and strong external predictive abilities for chemicals not used in model development. Furthermore, the contour maps from 3D models can provide an intuitive understanding of the key structure features responsible for the antimalarial activities. In conclusion, we summarize the detailed position-specific structural requirements of these derivatives accordingly. All these results are helpful for the rational design of new compounds with higher antimalarial bioactivities.
Transonic solutions for a multielement airfoil using the full-potential equation
NASA Technical Reports Server (NTRS)
Flores, J.; Holst, T. L.; Sorenson, R. L.
1984-01-01
Transonic flow solutions are obtained over a multielement airfoil (augmentor-wing) using the full-potential equation. Solutions obtained for a subcritical case and a strong shock case show good quantitative agreement with experiment in regions not dominated by viscous effects. In those regions where viscous effects are dominant, the results are still in good qualitative agreement. For the strong shock case, Mach number and angle-of-attack corrections were necessary to match experimental coefficient of lift. Typical results from the transonic augmentor-wing Potential Code on the Cray-1S computer require about 10 sec of CPU time for a three-order-of-magnitude drop in the maximum residual. The speed with which solutions can be generated, and the associated low cost, will make this code a practical tool for the design aerodynamicist.
Three-dimensional local structure refinement using a full-potential XANES analysis
Smolentsev, G.; Soldatov, A. V.; Feiters, M. C.
2007-04-01
A technique of three-dimensional (3D) local structure refinement is proposed and demonstrated by applying it to the metal complex Ni(acacR){sub 2}. The method is based on the fitting of experimental x-ray absorption near-edge structure (XANES) using a multidimensional interpolation of spectra and full potential calculations of XANES. The low number of calculations required is the main advantage of the method, which allows a computationally time-expensive method using a non-muffin-tin potential to be applied. The possibility to determine bond angles in addition to bond lengths accessible to extended x-ray-absorption fine structure opens new perspectives of XANES as a 3D structure probe.
A full-potential approach to the relativistic single-site Green's function
Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Stocks, George Malcolm
2016-07-07
One major purpose of studying the single-site scattering problem is to obtain the scattering matrices and differential equation solutions indispensable to multiple scattering theory (MST) calculations. On the other hand, the single-site scattering itself is also appealing because it reveals the physical environment experienced by electrons around the scattering center. In this study, we demonstrate a new formalism to calculate the relativistic full-potential single-site Green's function. We implement this method to calculate the single-site density of states and electron charge densities. Lastly, the code is rigorously tested and with the help of Krein's theorem, the relativistic effects and full potentialmore » effects in group V elements and noble metals are thoroughly investigated.« less
A hybrid Navier-Stokes/full-potential method for the prediction of iced wing aerodynamics
NASA Technical Reports Server (NTRS)
Mello, O. A. F.; Sankar, L. N.
1994-01-01
A hybrid method for computing compressible viscous flows is presented. This method divides the computational domain into two zones. In the outer zone, the unsteady full-potential equation (FPE) is solved. In the inner zone, the Navier-Stokes equations are solved. The two zones are tightly coupled so that steady and unsteady flows may be efficiently solved. The resulting CPU times are less than 50 percent of the required for a full-blown Navier-Stokes analysis. Sample applications of the method to an unswept iced wing at 4 deg and 8 deg angle of attack are presented. Surface pressures are in good agreement with the measurements obtained by Bragg et al. at the University of Illinois.
Electronic and magnetic properties of Cr doped graphene; Full potential approach
Thakur, Jyoti Kashyap, Manish K.; Saini, Hardev S.
2015-08-28
The electronic and magnetic properties of pristine and Cr doped graphene have been calculated using WIEN2k implementation of full potential linearized augmented plane wave (FPLAPW) method based on Density Functional Theory (DFT). The exchange and correlation (XC) effects were taken into account by generalized gradient approximation (GGA). The calculated results show that Cr doping introduces appropriate magnetic moment on graphene. The p-d interaction between 3d states of Cr atom and p-states of C atom are responsible for half metallicity in graphene. The calculated Half-metallic behavior of Cr-doped graphene makes it an ideal candidate for spintronic applications.
NASA Technical Reports Server (NTRS)
Farrell, C.; Adamczyk, J.
1981-01-01
The three-dimensional flow in a turbomachinery blade row was approximated by correcting for streamtube convergence and radius change in the throughflow direction. The method is a fully conservative solution of the full potential equation incorporating the finite volume technique on body fitted periodic mesh, with an artificial density imposed in the transonic region to insure stability and the capture of shock waves. Comparison of results for several supercritical blades shows good agreement with their hodograph solutions. Other calculations for these profiles as well as standard NACA blade sections indicate that this is a useful scheme analyzing both the design and off-design performance of turbomachinery blading.
Relativistic Green's Functions in Full-Potential Multiple-Scattering Theory
NASA Astrophysics Data System (ADS)
Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Stocks, G. Malcolm
The Green's functions play a central role in MST based KKR method. Obtaining the Green's functions by solving the Dirac equation is appealing since it naturally incorporated the electron spin and the spin-orbit coupling effects. Here we implemented the full-potential relativistic KKR method using a technique called the sine and cosine matrices formalism. The charge density and the density of states of some pure element crystals have been calculated. Different expressions of the Green's functions have been investigated for numerical benefits.
Keller, Kathleen L; Assur, Shaziya A; Torres, Mindy; Lofink, Hayley E; Thornton, John C; Faith, Myles S; Kissileff, Harry R
2006-09-01
Improving children's abilities to recognize when they are full is one strategy to prevent overweight, but currently, there are few validated instruments to assist this process. In the present study, we developed and tested the potential of an analog scaling device for quantifying sensations such as fullness in 4-5 year old children. The device was a picture of a doll with a rectangular stomach over which a sliding bar could be moved to communicate rated fullness levels. Eleven 4-5 year old children were shown pictures of French fries and fruit salad in five varying portion sizes that increased in diameter exponentially by a power of 1.5, ranging from 5.2 to 18.5 cm. Success in using the device was predefined as an increase in ratings as a function of increasing portion size, in at least one of two trials. Eight children were successful with the fries, and ten were successful with the fruit salad. Mean ratings across children were significantly different from each other for both foods. These data show that children can be trained to use an analog scale to quantify differences in portion sizes of foods. Future experiments will validate this scaling procedure for measuring fullness in real eating situations. If successful, this methodology might have applications to the measurement of other bodily sensations in young children.
NASA Technical Reports Server (NTRS)
Laming, J. Martin; Drake, J. J.; Widing, Kenneth G.
1995-01-01
In this paper we reanalayze the full-disk quiet-sun spectrum of Mallinovsky & Heroux (1973) with modern atomic data. The purposes of this are to check our atomic data and methods in other investigations using data from nearby stars obtained with the NASA Extreme Ultraviolet Explorer (EUVE) satellite, and to confirm that the solar first ionization potential (FIP) effect investigated by previous authors studying discrete solar regions is the same as that found in full-disk spectra. We recover the usual solar FIP effect of a coronal abundance enhancement of elements with a low FIP of a factor approximately 3-4 for lines formed at temperatures greater than approximately 10(exp 6) K. For lower temperatures, the FIP effect seems to be substantially smaller, in qualitative agreement with other data. Comparing our full-disk result with those from discrete solar structures suggest that the FIP effect is a function of altitude, with the lower temperature full-disk emission being dominated by the super-granulation network. We also compare the recent ionization balance of Arnaud & Raymond (1992) with that of Arnaud & Rothenflug (1985).
Buhler, Sofie; Tedeschi, Tullia; Faccini, Andrea; Garino, Cristiano; Arlorio, Marco; Dossena, Arnaldo; Sforza, Stefano
2015-01-01
Non-specific lipid transfer proteins (nsLTP) were shown to be among the most significant allergens, in particular in several fruits belonging to the Rosaceae family. The molecular features of LTPs, such as the presence of eight cysteine residues forming four disulfide bridges, confer a compact structure, decreasing the probability of degradation due to cooking or digestion, thereby increasing the chance of systemic absorption and severe allergic reactions. Few studies on LTP-induced allergies regarding almond (Prunus dulcis L) are available in the literature. In the present work, we describe for the first time the extraction and purification of an almond LTP, achieving its full characterisation by using liquid chromatography and exact mass spectrometry; the full sequence was identified by means of LC-ESI-Orbitrap-MS applying a bottom-up approach. The characterised protein consists of 92 amino acids and has a calculated exact MW of 9579.0. The presence of four disulfide bridges was confirmed after reduction, as shown by a mass increment of 8 Da. Finally, its potential allergenicity was confirmed via an in silico approach. The results presented here demonstrate the enormous potential of advanced MS techniques for obtaining high-quality structural and functional data of allergenic proteins in a short time.
Zubiaga, A; Tuomisto, F; Puska, M J
2015-01-29
We investigate the modeling of positronium (Ps) states and their pick-off annihilation trapped at open volumes pockets in condensed molecular matter. Our starting point is the interacting many-body system of Ps and a He atom because it is the smallest entity that can mimic the energy gap between the highest occupied and lowest unoccupied molecular orbitals of molecules, and yet the many-body structure of the HePs system can be calculated accurately enough. The exact-diagonalization solution of the HePs system enables us to construct a pairwise full-correlation single-particle potential for the Ps-He interaction, and the total potential in solids is obtained as a superposition of the pairwise potentials. We study in detail Ps states and their pick-off annihilation rates in voids inside solid He and analyze experimental results for Ps-induced voids in liquid He obtaining the radii of the voids. More importantly, we generalize our conclusions by testing the validity of the Tao-Eldrup model, widely used to analyze ortho-Ps annihilation measurements for voids in molecular matter, against our theoretical results for the solid He. Moreover, we discuss the influence of the partial charges of polar molecules and the strength of the van der Waals interaction on the pick-off annihilation rate. PMID:25523231
NASA Astrophysics Data System (ADS)
Shimizu, A.; Ido, T.; Kurachi, M.; Makino, R.; Nishiura, M.; Kato, S.; Nishizawa, A.; Hamada, Y.
2014-11-01
Two-dimensional potential profiles in the Large Helical Device (LHD) were measured with heavy ion beam probe (HIBP). To measure the two-dimensional profile, the probe beam energy has to be changed. However, this task is not easy, because the beam transport line of LHD-HIBP system is very long (˜20 m), and the required beam adjustment consumes much time. To reduce the probe beam energy adjustment time, an automatic beam adjustment system has been developed. Using this system, required time to change the probe beam energy is dramatically reduced, such that two-dimensional potential profiles were able to be successfully measured with HIBP by changing the probe beam energy shot to shot.
Shimizu, A. Ido, T.; Kato, S.; Hamada, Y.; Kurachi, M.; Makino, R.; Nishiura, M.; Nishizawa, A.
2014-11-15
Two-dimensional potential profiles in the Large Helical Device (LHD) were measured with heavy ion beam probe (HIBP). To measure the two-dimensional profile, the probe beam energy has to be changed. However, this task is not easy, because the beam transport line of LHD-HIBP system is very long (∼20 m), and the required beam adjustment consumes much time. To reduce the probe beam energy adjustment time, an automatic beam adjustment system has been developed. Using this system, required time to change the probe beam energy is dramatically reduced, such that two-dimensional potential profiles were able to be successfully measured with HIBP by changing the probe beam energy shot to shot.
Rao, R Nageswara; Maurya, Pawan K; Raju, A Narasa
2009-07-12
During the process development of phenazopyridine HCl bulk drug, a potential impurity was detected in the routine impurity profiles by HPLC. Using MS-MS and multidimensional NMR techniques, the trace level impurity was unambiguously identified to be 3-phenyl-5-phenylazo-pyridine-2,6-diamine after its isolation from phenazopyridine HCl by semi-preparative HPLC. The formation of the impurity was discussed. To our knowledge, it is a novel impurity not reported elsewhere.
Numerical calculation of steady inviscid full potential compressible flow about wind turbine blades
NASA Technical Reports Server (NTRS)
Dulikravich, D. S.
1980-01-01
The air flow through a propeller-type wind turbine rotor is characterized by three-dimensional rotating cascade effects about the inner portions of the rotor blades and compressibility effects about the tip regions of the blades. In the case of large rotor diameter and/or increased rotor angular speed, the existence of small supersonic zones terminated by weak shocks is possible. An exact nonlinear mathematical model (called a steady Full Potential Equation - FPE) that accounts for the above phenomena has been rederived. An artificially time dependent version of FPE was iteratively solved by a finite volume technique involving an artificial viscosity and a three-level consecutive mesh refinement. The exact boundary conditions were applied by generating a boundary conforming periodic computation mesh.
A full nine-dimensional potential-energy surface for hydrogen molecule-water collisions.
Faure, Alexandre; Valiron, Pierre; Wernli, Michael; Wiesenfeld, Laurent; Rist, Claire; Noga, Josef; Tennyson, Jonathan
2005-06-01
The hydrogen and water molecules are ubiquitous in the Universe. Their mutual collisions drive water masers and other line emission in various astronomical environments, notably molecular clouds and star-forming regions. We report here a full nine-dimensional interaction potential for H2O-H2 calibrated using high-accuracy, explicitly correlated wave functions. All degrees of freedom are included using a systematic procedure transferable to other small molecules of astrophysical or atmospherical relevance. As a first application, we present rate constants for the vibrational relaxation of the upsilon2 bending mode of H2O obtained from quasiclassical trajectory calculations in the temperature range of 500-4000 K. Our high-temperature (T > or = 1500 K) results are found compatible with the single experimental value at 295 K. Our rates are also significantly larger than those currently used in the astrophysical literature and will lead to a thorough reinterpretation of vibrationally excited water emission spectra from space.
Parallel Newton-Krylov-Schwarz algorithms for the transonic full potential equation
NASA Technical Reports Server (NTRS)
Cai, Xiao-Chuan; Gropp, William D.; Keyes, David E.; Melvin, Robin G.; Young, David P.
1996-01-01
We study parallel two-level overlapping Schwarz algorithms for solving nonlinear finite element problems, in particular, for the full potential equation of aerodynamics discretized in two dimensions with bilinear elements. The overall algorithm, Newton-Krylov-Schwarz (NKS), employs an inexact finite-difference Newton method and a Krylov space iterative method, with a two-level overlapping Schwarz method as a preconditioner. We demonstrate that NKS, combined with a density upwinding continuation strategy for problems with weak shocks, is robust and, economical for this class of mixed elliptic-hyperbolic nonlinear partial differential equations, with proper specification of several parameters. We study upwinding parameters, inner convergence tolerance, coarse grid density, subdomain overlap, and the level of fill-in in the incomplete factorization, and report their effect on numerical convergence rate, overall execution time, and parallel efficiency on a distributed-memory parallel computer.
Electronic and magnetic properties of Mo doped graphene; full potential approach
Thakur, Jyoti Kashyap, Manish K.; Singh, Mukhtiyar; Saini, Hardev S.
2015-05-15
The electronic and magnetic properties of Pristine and Mo doped Graphene have been calculated using WIEN2k implementation of full potential linearized augmented plane wave (FPLAPW) method based on Density Functional Theory (DFT). The exchange and correlation (XC) effects were taken into account by generalized gradient approximation (GGA). The calculated results show that Mo doping creates magnetism in Graphene by shifting the energy levels at E{sub F} and opens up a channel for Graphene to be used in real nanoscale device applications. The unpaired d-electrons of Mo atom are responsible for induced magnetism in Graphene. Magnetic ordering created in Graphene in this way makes it suitable for recording media, magnetic sensors, magnetic inks and spintronic devices.
Transonic flow analysis for rotors. Part 2: Three-dimensional, unsteady, full-potential calculation
NASA Technical Reports Server (NTRS)
Chang, I. C.
1985-01-01
A numerical method is presented for calculating the three-dimensional unsteady, transonic flow past a helicopter rotor blade of arbitrary geometry. The method solves the full-potential equations in a blade-fixed frame of reference by a time-marching implicit scheme. At the far-field, a set of first-order radiation conditions is imposed, thus minimizing the reflection of outgoing wavelets from computational boundaries. Computed results are presented to highlight radial flow effects in three dimensions, to compare surface pressure distributions to quasi-steady predictions, and to predict the flow field on a swept-tip blade. The results agree well with experimental data for both straight- and swept-tip blade geometries.
NASA Astrophysics Data System (ADS)
Wang, R.; Gu, Y. J.; Schultz, R.; Kim, A.; Chen, Y.
2015-12-01
During the past four years, the number of earthquakes with magnitudes greater than three has substantially increased in the southern section of Western Canada Sedimentary Basin (WCSB). While some of these events are likely associated with tectonic forces, especially along the foothills of the Canadian Rockies, a significant fraction occurred in previously quiescent regions and has been linked to waste water disposal or hydraulic fracturing. A proper assessment of the origin and source properties of these 'induced earthquakes' requires careful analyses and modeling of regional broadband data, which steadily improved during the past 8 years due to recent establishments of regional broadband seismic networks such as CRANE, RAVEN and TD. Several earthquakes, especially those close to fracking activities (e.g. Fox creek town, Alberta) are analyzed. Our preliminary full moment tensor inversion results show maximum horizontal compressional orientations (P-axis) along the northeast-southwest orientation, which agree with the regional stress directions from borehole breakout data and the P-axis of historical events. The decomposition of those moment tensors shows evidence of strike-slip mechanism with near vertical fault plane solutions, which are comparable to the focal mechanisms of injection induced earthquakes in Oklahoma. Minimal isotropic components have been observed, while a modest percentage of compensated-linear-vector-dipole (CLVD) components, which have been linked to fluid migraition, may be required to match the waveforms. To further evaluate the non-double-couple components, we compare the outcomes of full, deviatoric and pure double couple (DC) inversions using multiple frequency ranges and phases. Improved location and depth information from a novel grid search greatly assists the identification and classification of earthquakes in potential connection with fluid injection or extraction. Overall, a systematic comparison of the source attributes of
Hey, Tobias; Jönsson, Karin; Jansen, Jes la Cour
2012-01-01
The potential effects of altering primary settlers during biological in-line hydrolysis and converting a nitrifying activated sludge process into a partial pre-denitrification process for the purpose of resource conservation were evaluated. A full-scale primary sludge hydrolysis experiment was performed at a wastewater treatment plant and implemented in a dynamic modelling tool based on ASM2d. The full-scale hydrolysis experiment achieved a volatile fatty acid (VFA) production of 43 g COD(HAc) x m(-3) with no release of ammonium. Additional nitrogen removal of 44 t N x a(-1) was simulated, and the produced hydrolysate was able to replace 50% of the annual ethanol usage. Furthermore, 196 MWh of electricity per annum could be saved through the reduction of ethanol production and the optimization of the operation strategy of the activated sludge tank by operating a different number of anoxic zones.
2D materials for nanophotonic devices
NASA Astrophysics Data System (ADS)
Xu, Renjing; Yang, Jiong; Zhang, Shuang; Pei, Jiajie; Lu, Yuerui
2015-12-01
Two-dimensional (2D) materials have become very important building blocks for electronic, photonic, and phononic devices. The 2D material family has four key members, including the metallic graphene, transition metal dichalcogenide (TMD) layered semiconductors, semiconducting black phosphorous, and the insulating h-BN. Owing to the strong quantum confinements and defect-free surfaces, these atomically thin layers have offered us perfect platforms to investigate the interactions among photons, electrons and phonons. The unique interactions in these 2D materials are very important for both scientific research and application engineering. In this talk, I would like to briefly summarize and highlight the key findings, opportunities and challenges in this field. Next, I will introduce/highlight our recent achievements. We demonstrated atomically thin micro-lens and gratings using 2D MoS2, which is the thinnest optical component around the world. These devices are based on our discovery that the elastic light-matter interactions in highindex 2D materials is very strong. Also, I would like to introduce a new two-dimensional material phosphorene. Phosphorene has strongly anisotropic optical response, which creates 1D excitons in a 2D system. The strong confinement in phosphorene also enables the ultra-high trion (charged exciton) binding energies, which have been successfully measured in our experiments. Finally, I will briefly talk about the potential applications of 2D materials in energy harvesting.
Full-dimensional (15-dimensional) ab initio analytical potential energy surface for the H7+ cluster
NASA Astrophysics Data System (ADS)
Barragán, Patricia; Prosmiti, Rita; Wang, Yimin; Bowman, Joel M.
2012-06-01
Full-dimensional ab initio potential energy surface is constructed for the H_7^+ cluster. The surface is a fit to roughly 160 000 interaction energies obtained with second-order MöllerPlesset perturbation theory and the cc-pVQZ basis set, using the invariant polynomial method [B. J. Braams and J. M. Bowman, Int. Rev. Phys. Chem. 28, 577 (2009), 10.1080/01442350903234923]. We employ permutationally invariant basis functions in Morse-type variables for all the internuclear distances to incorporate permutational symmetry with respect to interchange of H atoms into the representation of the surface. We describe how different configurations are selected in order to create the database of the interaction energies for the linear least squares fitting procedure. The root-mean-square error of the fit is 170 cm-1 for the entire data set. The surface dissociates correctly to the H_5^+ + H2 fragments. A detailed analysis of its topology, as well as comparison with additional ab initio calculations, including harmonic frequencies, verify the quality and accuracy of the parameterized potential. This is the first attempt to present an analytical representation of the 15-dimensional surface of the H_7^+ cluster for carrying out dynamics studies.
Bourke, J D; Islam, M T; Best, S P; Tran, C Q; Wang, F; Chantler, C T
2016-07-21
Recent high-accuracy X-ray absorption measurements of the sandwich organometallics ferrocene (Fc) and decamethylferrocene (DmFc) at temperatures close to liquid helium are compared with new full-potential modeling of X-ray absorption fine structure (XAFS) covering the near-edge region (XANES) and above up to k = 7 Å(-1). The implementation of optimized calculations of the oscillatory part of the spectrum from the package FDMX allows detailed study of the spectra in regions of the photoelectron momentum most sensitive to differences in the molecular stereochemistry. For Fc and DmFc, this corresponds to the relative rotation of the cyclopentadienyl rings. When applied to high-accuracy XAFS of Fc and DmFc, the FDMX theory gives clear evidence for the eclipsed conformation for Fc and the staggered conformation for DmFc for frozen solutions at ca. 15 K. This represents the first clear experimental assignment of the solution structures of Fc and DmFc and reveals the potential of high-accuracy XAFS for structural analysis. PMID:27391765
NASA Astrophysics Data System (ADS)
Athens, N.; Fontiveros, V. C.; Klemperer, S. L.; Egger, A. E.; Glen, J. M.
2010-12-01
desert environments. The ATV’s induced magnetic field is accounted for by a heading correction, similar to that used in aeromagnetic surveys, and the overall noise level of the system is ~ 4 nT. We collected ~ 300 km of magnetic data in 2 days, imaging a 400 nT N-S-trending magnetic high. Modeling of the potential-field data confirms the interpretation of the seismic data of a buried east-dipping normal fault. Future potential-field modeling will look at whether this tectonic model can be applied north of the seismic line where the magnetic anomaly broadens significantly or whether an intrusive body is necessary, signaling contemporaneous volcanic activity with faulting. The outcome of our study validates our strategy of rapid potential-field profiling over large areas to identify specific targets for more intensive and expensive seismic profiles, the interpretation of which can be validated by detailed potential-field modeling.
NASA Technical Reports Server (NTRS)
Farrell, C. A.
1994-01-01
A computer program, QSONIC, has been developed for calculating the full potential, transonic quasi-three-dimensional flow through a rotating turbomachinery blade row. The need for lighter, more efficient turbomachinery components has led to the consideration of machines with fewer stages, each with blades capable of higher speeds and higher loading. As speeds increase, the numerical problems inherent in the transonic regime have to be resolved. These problems include the calculation of imbedded shock discontinuities and the dual nature of the governing equations, which are elliptic in the subcritical flow regions but become hyperbolic for supersonic zones. QSONIC provides the flow analyst with a fast and reliable means of obtaining the transonic potential flow distribution on a blade-to-blade stream surface of a stationary or rotating turbomachine blade row. QSONIC combines several promising transonic analysis techniques. The full potential equation in conservative form is discretized at each point on a body-fitted period mesh. A mass balance is calculated through the finite volume surrounding each point. Each local volume is corrected in the third dimension for any change in stream-tube thickness along the stream tube. The nonlinear equations for all volumes are of mixed type (elliptic or hyperbolic) depending on the local Mach number. The final result is a block-tridiagonal matrix formulation involving potential corrections at each grid point as the unknowns. The residual of each system of equations is solved along each grid line. At points where the Mach number exceeds unity, the density at the forward (sweeping) edge of the volume is replaced by an artificial density. This method calculates the flow field about a cascade of arbitrary two-dimensional airfoils. Three-dimensional flow is approximated in a turbomachinery blade row by correcting for stream-tube convergence and radius change in the through flow direction. Several significant assumptions were made in
NASA Astrophysics Data System (ADS)
Wang, Jin; Ma, Jianyong; Zhou, Changhe
2014-11-01
A 3×3 high divergent 2D-grating with period of 3.842μm at wavelength of 850nm under normal incidence is designed and fabricated in this paper. This high divergent 2D-grating is designed by the vector theory. The Rigorous Coupled Wave Analysis (RCWA) in association with the simulated annealing (SA) is adopted to calculate and optimize this 2D-grating.The properties of this grating are also investigated by the RCWA. The diffraction angles are more than 10 degrees in the whole wavelength band, which are bigger than the traditional 2D-grating. In addition, the small period of grating increases the difficulties of fabrication. So we fabricate the 2D-gratings by direct laser writing (DLW) instead of traditional manufacturing method. Then the method of ICP etching is used to obtain the high divergent 2D-grating.
NASA Technical Reports Server (NTRS)
Trejo, Leonard J.; Matthews, Bryan; Rosipal, Roman
2005-01-01
We have developed and tested two EEG-based brain-computer interfaces (BCI) for users to control a cursor on a computer display. Our system uses an adaptive algorithm, based on kernel partial least squares classification (KPLS), to associate patterns in multichannel EEG frequency spectra with cursor controls. Our first BCI, Target Practice, is a system for one-dimensional device control, in which participants use biofeedback to learn voluntary control of their EEG spectra. Target Practice uses a KF LS classifier to map power spectra of 30-electrode EEG signals to rightward or leftward position of a moving cursor on a computer display. Three subjects learned to control motion of a cursor on a video display in multiple blocks of 60 trials over periods of up to six weeks. The best subject s average skill in correct selection of the cursor direction grew from 58% to 88% after 13 training sessions. Target Practice also implements online control of two artifact sources: a) removal of ocular artifact by linear subtraction of wavelet-smoothed vertical and horizontal EOG signals, b) control of muscle artifact by inhibition of BCI training during periods of relatively high power in the 40-64 Hz band. The second BCI, Think Pointer, is a system for two-dimensional cursor control. Steady-state visual evoked potentials (SSVEP) are triggered by four flickering checkerboard stimuli located in narrow strips at each edge of the display. The user attends to one of the four beacons to initiate motion in the desired direction. The SSVEP signals are recorded from eight electrodes located over the occipital region. A KPLS classifier is individually calibrated to map multichannel frequency bands of the SSVEP signals to right-left or up-down motion of a cursor on a computer display. The display stops moving when the user attends to a central fixation point. As for Target Practice, Think Pointer also implements wavelet-based online removal of ocular artifact; however, in Think Pointer muscle
Unlocking the full potential of Earth observation during the 2015 Texas flood disaster
NASA Astrophysics Data System (ADS)
Schumann, G. J.-P.; Frye, S.; Wells, G.; Adler, R.; Brakenridge, R.; Bolten, J.; Murray, J.; Slayback, D.; Policelli, F.; Kirschbaum, D.; Wu, H.; Cappelaere, P.; Howard, T.; Flamig, Z.; Clark, R.; Stough, T.; Chini, M.; Matgen, P.; Green, D.; Jones, B.
2016-05-01
Intense rainfall during late April and early May 2015 in Texas and Oklahoma led to widespread and sustained flooding in several river basins. Texas state agencies relevant to emergency response were activated when severe weather then ensued for 6 weeks from 8 May until 19 June following Tropical Storm Bill. An international team of scientists and flood response experts assembled and collaborated with decision-making authorities for user-driven high-resolution satellite acquisitions over the most critical areas; while experimental automated flood mapping techniques provided daily ongoing monitoring. This allowed mapping of flood inundation from an unprecedented number of spaceborne and airborne images. In fact, a total of 27,174 images have been ingested to the USGS Hazards Data Distribution System (HDDS) Explorer, except for the SAR images used. Based on the Texas flood use case, we describe the success of this effort as well as the limitations in fulfilling the needs of the decision-makers, and reflect upon these. In order to unlock the full potential for Earth observation data in flood disaster response, we suggest in a call for action (i) stronger collaboration from the onset between agencies, product developers, and decision-makers; (ii) quantification of uncertainties when combining data from different sources in order to augment information content; (iii) include a default role for the end-user in satellite acquisition planning; and (iv) proactive assimilation of methodologies and tools into the mandated agencies.
Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology
Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr
2016-01-01
The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346
Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.
Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr
2016-01-01
The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.
NASA Astrophysics Data System (ADS)
Cheng, Chingyun; Kangara, Jayampathi; Arakelyan, Ilya; Thomas, John
2016-05-01
We tune the dimensionality of a strongly interacting degenerate 6 Li Fermi gas from 2D to quasi-2D, by adjusting the radial confinement of pancake-shaped clouds to control the radial chemical potential. In the 2D regime with weak radial confinement, the measured pair binding energies are in agreement with 2D-BCS mean field theory, which predicts dimer pairing energies in the many-body regime. In the qausi-2D regime obtained with increased radial confinement, the measured pairing energy deviates significantly from 2D-BCS theory. In contrast to the pairing energy, the measured radii of the cloud profiles are not fit by 2D-BCS theory in either the 2D or quasi-2D regimes, but are fit in both regimes by a beyond mean field polaron-model of the free energy. Supported by DOE, ARO, NSF, and AFOSR.
Hydrodynamic parameters estimation from self-potential data in a controlled full scale site
NASA Astrophysics Data System (ADS)
Chidichimo, Francesco; De Biase, Michele; Rizzo, Enzo; Masi, Salvatore; Straface, Salvatore
2015-03-01
A multi-physical approach developed for the hydrodynamic characterization of porous media using hydrogeophysical information is presented. Several pumping tests were performed in the Hydrogeosite Laboratory, a controlled full-scale site designed and constructed at the CNR-IMAA (Consiglio Nazionale delle Ricerche - Istituto di Metodologia per l'Analisi Ambientale), in Marsico Nuovo (Basilicata Region, Southern Italy), in order to obtain an intermediate stage between laboratory experiments and field survey. The facility consists of a pool, used to study water infiltration processes, to simulate the space and time dynamics of subsurface contamination phenomena, to improve and to find new relationship between geophysical and hydrogeological parameters, to test and to calibrate new geophysical techniques and instruments. Therefore, the Hydrogeosite Laboratory has the advantage of carrying out controlled experiments, like in a flow cell or sandbox, but at field comparable scale. The data collected during the experiments have been used to estimate the saturated hydraulic conductivity ks [ms-1] using a coupled inversion model working in transient conditions, made up of the modified Richards equation describing the water flow in a variably saturated porous medium and the Poisson equation providing the self-potential ϕ [V], which naturally occurs at points of the soil surface owing to the presence of an electric field produced by the motion of underground electrolytic fluids through porous systems. The result obtained by this multi-physical numerical approach, which removes all the approximations adopted in previous works, makes a useful instrument for real heterogeneous aquifer characterization and for predictive analysis of its behavior.
NASA Astrophysics Data System (ADS)
Majumder, Moumita; Dawes, Richard; Wang, Xiao-Gang; Carrington, Tucker; Li, Jun; Guo, Hua; Manzhos, Sergei
2014-06-01
New potential energy surfaces for methane were constructed, represented as analytic fits to about 100,000 individual high-level ab initio data. Explicitly-correlated multireference data (MRCI-F12(AE)/CVQZ-F12) were computed using Molpro [1] and fit using multiple strategies. Fits with small to negligible errors were obtained using adaptations of the permutation-invariant-polynomials (PIP) approach [2,3] based on neural-networks (PIP-NN) [4,5] and the interpolative moving least squares (IMLS) fitting method [6] (PIP-IMLS). The PESs were used in full-dimensional vibrational calculations with an exact kinetic energy operator by representing the Hamiltonian in a basis of products of contracted bend and stretch functions and using a symmetry adapted Lanczos method to obtain eigenvalues and eigenvectors. Very close agreement with experiment was produced from the purely ab initio PESs. References 1- H.-J. Werner, P. J. Knowles, G. Knizia, 2012.1 ed. 2012, MOLPRO, a package of ab initio programs. see http://www.molpro.net. 2- Z. Xie and J. M. Bowman, J. Chem. Theory Comput 6, 26, 2010. 3- B. J. Braams and J. M. Bowman, Int. Rev. Phys. Chem. 28, 577, 2009. 4- J. Li, B. Jiang and Hua Guo, J. Chem. Phys. 139, 204103 (2013). 5- S Manzhos, X Wang, R Dawes and T Carrington, JPC A 110, 5295 (2006). 6- R. Dawes, X-G Wang, A.W. Jasper and T. Carrington Jr., J. Chem. Phys. 133, 134304 (2010).
NASA Astrophysics Data System (ADS)
Ravindran, P.; Kjekshus, A.; Fjellvåg, H.; James, P.; Nordström, L.; Johansson, B.; Eriksson, O.
2001-04-01
The computational framework of this study is based on the local-spin-density approximation with first-principles full-potential linear muffin-tin orbital calculations including orbital polarization (OP) correction. We have studied the magnetic anisotropy for a series of bilayer CuAu(I)-type materials such as FeX, MnX (X=Ni,Pd,Pt), CoPt, NiPt, MnHg, and MnRh in a ferromagnetic state using experimental structural parameters to understand the microscopic origin of magnetic-anisotropy energy (MAE) in magnetic multilayers. Except for MnRh and MnHg, all these phases show perpendicular magnetization. We have analyzed our results in terms of angular momentum-, spin- and site-projected density of states, magnetic-angular-momentum-projected density of states, orbital-moment density of states, and total density of states. The orbital-moment number of states and the orbital-moment anisotropy for FeX (X=Ni,Pd,Pt) are calculated as a function of band filling to study its effect on MAE. The total and site-projected spin and orbital moments for all these systems are calculated with and without OP when the magnetization is along or perpendicular to the plane. The results are compared with available experimental as well as theoretical results. Our calculations show that OP always enhances the orbital moment in these phases and brings them closer to experimental values. The changes in MAE are analyzed in terms of exchange splitting, spin-orbit splitting, and tetragonal distortion/crystal-field splitting. The calculated MAE is found to be in good agreement with experimental values when the OP correction is included. Some of the materials considered here show large magnetic anisotropy of the order of meV. In particular we found that MnPt will have a very large MAE if it could be stabilized in a ferromagnetic configuration. Our analysis indicates that apart from large spin-orbit interaction and exchange interaction from at least one of the constituents, a large crystal-field splitting
NASA Astrophysics Data System (ADS)
Trampedach, Regner
s astrophysics program, and in particular that of the Kepler mission and the recently approved TESS mission. This analysis will remove the largest systematic effect in asteroseismology and make it possible to realize the full potential for mode-frequencies to strongly constrain stellar models and the properties of stars.
Parallel stitching of 2D materials
Ling, Xi; Wu, Lijun; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; et al
2016-01-27
Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.
Parallel Stitching of 2D Materials.
Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing
2016-03-23
Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.
Baiz, Carlos R.; Schach, Denise; Tokmakoff, Andrei
2014-01-01
We describe a microscope for measuring two-dimensional infrared (2D IR) spectra of heterogeneous samples with μm-scale spatial resolution, sub-picosecond time resolution, and the molecular structure information of 2D IR, enabling the measurement of vibrational dynamics through correlations in frequency, time, and space. The setup is based on a fully collinear “one beam” geometry in which all pulses propagate along the same optics. Polarization, chopping, and phase cycling are used to isolate the 2D IR signals of interest. In addition, we demonstrate the use of vibrational lifetime as a contrast agent for imaging microscopic variations in molecular environments. PMID:25089490
Evans, C. M. Krynski, Kamil; Streeter, Zachary; Findley, G. L.
2015-12-14
We present for the first time the quasi-free electron energy V{sub 0}(ρ) for H{sub 2}, D{sub 2}, and O{sub 2} from gas to liquid densities, on noncritical isotherms and on a near critical isotherm in each fluid. These data illustrate the ability of field enhanced photoemission (FEP) to determine V{sub 0}(ρ) accurately in strongly absorbing fluids (e.g., O{sub 2}) and fluids with extremely low critical temperatures (e.g., H{sub 2} and D{sub 2}). We also show that the isotropic local Wigner-Seitz model for V{sub 0}(ρ) — when coupled with thermodynamic data for the fluid — can yield optimized parameters for intermolecular potentials, as well as zero kinetic energy electron scattering lengths.
NASA Astrophysics Data System (ADS)
Isegawa, Miho; Liu, Fengyi; Maeda, Satoshi; Morokuma, Keiji
2014-10-01
We report reaction paths starting from N(2D) + H2O for doublet spin states, D0 and D1. The potential energy surfaces are explored in an automated fashion using the global reaction route mapping strategy. The critical points and reaction paths have been fully optimized at the complete active space second order perturbation theory level taking all valence electrons in the active space. In addition to direct dissociation pathways that would be dominant, three roaming processes, two roaming dissociation, and one roaming isomerization: (1) H2ON → H-O(H)N → H-HON → NO(2Π) + H2, (2) cis-HNOH → HNO-H → H-HNO → NO + H2, (3) H2NO → H-HNO → HNO-H → trans-HNOH, are confirmed on the D0 surface.
Santangelo Freel, Rose M.; Ogden, Kevin K.; Strong, Katie L.; Khatri, Alpa; Chepiga, Kathryn M.; Jensen, Henrik S.; Traynelis, Stephen F.; Liotta, Dennis C.
2015-01-01
We describe here the synthesis and evaluation of a series of tetrahydroisoquinolines that show subunit-selective potentiation of NMDA receptors containing the GluN2C or GluN2D subunits. Bischler-Napieralski conditions were employed in the key step for the conversion of acyclic amides to the corresponding tetrahydroisoquinoline containing analogs. Compounds were evaluated using both two electrode voltage clamp recordings from Xenopus laevis oocytes and imaging of mammalian BHK cells loaded with Ca2+-sensitive dyes. The most potent analogues had EC50 values of 300 nM and showed over 2-fold potentiation of the response to maximally effective concentrations of glutamate and glycine, but had no effect on responses from NMDA receptors containing the GluN2A or GluN2B subunits, AMPA, kainate, GABA, or glycine receptors or a variety of other potential targets. These compounds represent a potent class of small molecule subunit-selective potentiators of NMDA receptors. PMID:23627311
Orthotropic Piezoelectricity in 2D Nanocellulose
NASA Astrophysics Data System (ADS)
García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.
2016-10-01
The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.
Orthotropic Piezoelectricity in 2D Nanocellulose
García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.
2016-01-01
The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364
Optical modulators with 2D layered materials
NASA Astrophysics Data System (ADS)
Sun, Zhipei; Martinez, Amos; Wang, Feng
2016-04-01
Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.
2004-08-01
AnisWave2D is a 2D finite-difference code for a simulating seismic wave propagation in fully anisotropic materials. The code is implemented to run in parallel over multiple processors and is fully portable. A mesh refinement algorithm has been utilized to allow the grid-spacing to be tailored to the velocity model, avoiding the over-sampling of high-velocity materials that usually occurs in fixed-grid schemes.
FPCAS2D user's guide, version 1.0
NASA Astrophysics Data System (ADS)
Bakhle, Milind A.
1994-12-01
The FPCAS2D computer code has been developed for aeroelastic stability analysis of bladed disks such as those in fans, compressors, turbines, propellers, or propfans. The aerodynamic analysis used in this code is based on the unsteady two-dimensional full potential equation which is solved for a cascade of blades. The structural analysis is based on a two degree-of-freedom rigid typical section model for each blade. Detailed explanations of the aerodynamic analysis, the numerical algorithms, and the aeroelastic analysis are not given in this report. This guide can be used to assist in the preparation of the input data required by the FPCAS2D code. A complete description of the input data is provided in this report. In addition, four test cases, including inputs and outputs, are provided.
Shiran, Mohammad-Reza; Lennard, Martin S; Iqbal, Mohammad-Zafar; Lagundoye, Oldwale; Seivewright, Nicholas; Tucker, Geoffrey T; Rostami-Hodjegan, Amin
2009-01-01
AIMS To investigate the influence of different cytochrome P450 (CYP) activities and other potential covariates on the disposition of methadone in patients on methadone maintenance therapy (MMT). METHODS Eighty-eight patients (58 male; 21–55 years; 84 White) on MMT were studied. CYP2D6 activity [3 h plasma metabolic ratio of dextromethorphan (DEX) to dextrorphan (DOR)] was determined in 44 patients (29 male; 24–55 years), CYP1A2 activity (salivary caffeine elimination half-life) in 44 patients (21 male; 24–55 years) and CYP3A activity (oral clearance of midazolam) in 49 patients (33 male; 23–55 years). Data on all three CYPs were obtained from 32 subjects. Total plasma concentrations of (RS)-methadone and total and unbound plasma concentrations of both enantiomers were measured by LC/MS. Population pharmacokinetics and subsequent multiple regression analysis were used to calculate methadone oral clearance and to identify its covariates. RESULTS Between 61 and 68% of the overall variation in total plasma trough concentrations of (RS)-, (R)- and (S)-methadone was explained by methadone dose, duration of addiction before starting MMT, CYP3A activity and illicit morphine use. CYP3A activity explained 22, 16, 15 and 23% of the variation in unbound (R)-, unbound (S)-, total (RS)- and total (S)-methadone clearances, respectively. Neither CYP2D6 nor CYP1A2 activity was related to methadone disposition. CONCLUSIONS CYP3A activity has a modest influence on methadone disposition. Inhibitors and inducers of this enzyme should be monitored in patients taking methadone. PMID:19133059
Computational Screening of 2D Materials for Photocatalysis.
Singh, Arunima K; Mathew, Kiran; Zhuang, Houlong L; Hennig, Richard G
2015-03-19
Two-dimensional (2D) materials exhibit a range of extraordinary electronic, optical, and mechanical properties different from their bulk counterparts with potential applications for 2D materials emerging in energy storage and conversion technologies. In this Perspective, we summarize the recent developments in the field of solar water splitting using 2D materials and review a computational screening approach to rapidly and efficiently discover more 2D materials that possess properties suitable for solar water splitting. Computational tools based on density-functional theory can predict the intrinsic properties of potential photocatalyst such as their electronic properties, optical absorbance, and solubility in aqueous solutions. Computational tools enable the exploration of possible routes to enhance the photocatalytic activity of 2D materials by use of mechanical strain, bias potential, doping, and pH. We discuss future research directions and needed method developments for the computational design and optimization of 2D materials for photocatalysis.
Zbyszek Szeliga; Dagmar Juchelkova; Bohumir Cech; Pavel Kolat; Franz Winter; Adam J. Campen; Tomasz S. Wiltowski
2008-09-15
At present, natural limestone is used for the desulphurization of waste gases from the combustion of fossil fuels. However, it is important to save all primary resources, such as limestone, for the future. The researchers focused on finding alternative sorbents for the purpose of desulphurization in a dry additive method, which would become the alternative for natural limestone. This paper is primarily focused on desulphurization tests of selected substances. Tests were initially conducted on the laboratory scale, followed by pilot and full-scale combustion units. 15 refs., 9 figs., 5 tabs.
Xu, Minzhong; Sebastianelli, Francesco; Bacić, Zlatko
2008-06-28
We have performed rigorous quantum five-dimensional (5D) calculations and analysis of the translation-rotation (T-R) energy levels of one H(2), D(2), and HD molecule inside the small dodecahedral (H(2)O)(20) cage of the structure II clathrate hydrate, which was treated as rigid. The H(2)- cage intermolecular potential energy surface (PES) used previously in the molecular dynamics simulations of the hydrogen hydrates [Alavi et al., J. Chem. Phys. 123, 024507 (2005)] was employed. This PES, denoted here as SPC/E, combines an effective, empirical water-water pair potential [Berendsen et al., J. Phys. Chem. 91, 6269 (1987)] and electrostatic interactions between the partial charges placed on H(2)O and H(2). The 5D T-R eigenstates of HD were calculated also on another 5D H(2)-cage PES denoted PA-D, used by us earlier to investigate the quantum T-R dynamics of H(2) and D(2) in the small cage [Xu et al., J. Phys. Chem. B 110, 24806 (2006)]. In the PA-D PES, the hydrogen-water pair potential is described by the ab initio 5D PES of the isolated H(2)-H(2)O dimer. The quality of the SPC/E and the PA-D H(2)-cage PESs was tested by direct comparison of the T-R excitation energies calculated on them to the results of two recent inelastic neutron scattering (INS) studies of H(2) and HD inside the small clathrate cage. The translational fundamental and overtone excitations, as well as the triplet splittings of the j=0-->j=1 rotational transitions, of H(2) and HD in the small cage calculated on the SPC/E PES agree very well with the INS results and represent a significant improvement over the results computed on the PA-D PES. Our calculations on the SPC/E PES also make predictions about several spectroscopic observables for the encapsulated H(2), D(2), and HD, which have not been measured yet. PMID:18601373
New strategies in radiation therapy: exploiting the full potential of protons.
Mohan, Radhe; Mahajan, Anita; Minsky, Bruce D
2013-12-01
Protons provide significant dosimetric advantages compared with photons because of their unique depth-dose distribution characteristics. However, they are more sensitive to the effects of intra- and intertreatment fraction anatomic variations and uncertainties in treatment setup. Furthermore, in the current practice of proton therapy, the biologic effectiveness of protons relative to photons is assumed to have a generic fixed value of 1.1. However, this is a simplification, and it is likely higher in different portions of the proton beam. Current clinical practice and trials have not fully exploited the unique physical and biologic properties of protons. Intensity-modulated proton therapy, with its ability to manipulate energies (in addition to intensities), provides an entirely new dimension, which, with ongoing research, has considerable potential to increase the therapeutic ratio.
Realizing the full potential of Remotely Sensed Active Layer Thickness (ReSALT) Products
NASA Astrophysics Data System (ADS)
Schaefer, K. M.; Chen, A.; Liu, L.; Parsekian, A.; Jafarov, E. E.; Panda, S. K.; Zebker, H. A.
2015-12-01
The Remotely Sensed Active Layer Thickness (ReSALT) product uses the Interferometric Synthetic Aperture Radar (InSAR) technique to measure ground subsidence, active layer thickness (ALT), and thermokarst activity in permafrost regions. ReSALT supports research for the Arctic-Boreal Vulnerability Experiment (ABoVE) field campaign in Alaska and northwest Canada and is a precursor for a potential Nasa-Isro Synthetic Aperture Radar (NISAR) product. ALT is a critical parameter for monitoring the status of permafrost and thermokarst activity is one of the key drivers of change in permafrost regions. The ReSALT product currently includes 1) long-term subsidence trends resulting from the melting and subsequent drainage of excess ground ice in permafrost-affected soils, 2) seasonal subsidence resulting from the expansion of soil water into ice as the active layer freezes and thaws, and 3) ALT estimated from the seasonal subsidence assuming a vertical profile of water within the soil column. ReSALT includes uncertainties for all parameters and is validated against in situ measurements from the Circumpolar Active Layer Monitoring (CALM) network, Ground Penetrating Radar and mechanical probe measurements. We present high resolution ReSALT products on the North Slope of Alaska: Prudhoe Bay, Barrow, Toolik Lake, Happy Valley, and the Anaktuvuk fire zone. We believe that the ReSALT product could be expanded to include maps of individual thermokarst features identified as spatial anomalies in the subsidence trends, with quantified expansion rates. We illustrate the technique with multiple examples of thermokarst features on the North Slope of Alaska. Knowing the locations and expansion rates for individual features allows us to evaluate risks to human infrastructure. Our results highlight the untapped potential of the InSAR technique to remotely sense ALT and thermokarst dynamics over large areas of the Arctic.
The Cape Town Declaration on Vaccines 2012: Unlocking the full potential of vaccines in Africa.
Wiysonge, Charles S; Waggie, Zainab; Hawkridge, Anthony; Schoub, Barry D; Madhi, Shabir A; Rees, Helen; Hussey, Gregory D
2016-07-19
Delegates at the first International African Vaccinology Conference noted, with dismay, that many African children have limited access to existing and new vaccines as a consequence of weak immunisation programmes, lack of political will, and high vaccine prices. This inequality is a denial of the African child her basic right to a healthy life, and jeopardises long term economic growth on the continent. In addition, there is insufficient emphasis in Africa on adolescent and adult immunisation. The delegates documented various concerns and made various commitments; contained in this Cape Town Declaration on Vaccines, adopted on 11 November 2012. Finally, delegates confirmed their agreement with the goals and strategic objectives of the Global Vaccine Action Plan, and committed to hold African leaders accountable for its implementation during the Decade of Vaccines. The full list of registered conference delegates is provided as supplementary data to this manuscript. PMID:27317265
Jiang, Dadi; Brady, Colleen A; Johnson, Thomas M; Lee, Eunice Y; Park, Eunice J; Scott, Matthew P; Attardi, Laura D
2011-10-11
Over half of all human cancers, of a wide variety of types, sustain mutations in the p53 tumor suppressor gene. Although p53 limits tumorigenesis through the induction of apoptosis or cell cycle arrest, its molecular mechanism of action in tumor suppression has been elusive. The best-characterized p53 activity in vitro is as a transcriptional activator, but the identification of numerous additional p53 biochemical activities in vitro has made it unclear which mechanism accounts for tumor suppression. Here, we assess the importance of transcriptional activation for p53 tumor suppression function in vivo in several tissues, using a knock-in mouse strain expressing a p53 mutant compromised for transcriptional activation, p53(25,26). p53(25,26) is severely impaired for the transactivation of numerous classical p53 target genes, including p21, Noxa, and Puma, but it retains the ability to activate a small subset of p53 target genes, including Bax. Surprisingly, p53(25,26) can nonetheless suppress tumor growth in cancers derived from the epithelial, mesenchymal, central nervous system, and lymphoid lineages. Therefore, full transactivation of most p53 target genes is dispensable for p53 tumor suppressor function in a range of tissue types. In contrast, a transcriptional activation mutant that is completely defective for transactivation, p53(25,26,53,54), fails to suppress tumor development. These findings demonstrate that transcriptional activation is indeed broadly critical for p53 tumor suppressor function, although this requirement reflects the limited transcriptional activity observed with p53(25,26) rather than robust transactivation of a full complement of p53 target genes.
Yin, Chih-Chien; Li, Arvin Huang-Te; Chao, Sheng D.
2013-11-21
We have calculated the intermolecular interaction energies of the chloroform dimer in 12 orientations using the second-order Møller-Plesset perturbation theory. Single point energies of important geometries were calibrated by the coupled cluster with single and double and perturbative triple excitation method. Dunning's correlation consistent basis sets up to aug-cc-pVQZ have been employed in extrapolating the interaction energies to the complete basis set limit values. With the ab initio potential data we constructed a 5-site force field model for molecular dynamics simulations. We compared the simulation results with recent experiments and obtained quantitative agreements for the detailed atomwise radial distribution functions. Our results were also consistent with previous results using empirical force fields with polarization effects. Moreover, the calculated diffusion coefficients reproduced the experimental data over a wide range of thermodynamic conditions. To the best of our knowledge, this is the first ab initio force field which is capable of competing with existing empirical force fields for liquid chloroform.
Full dimension Rb2He ground triplet potential energy surface and quantum scattering calculations.
Guillon, Grégoire; Viel, Alexandra; Launay, Jean-Michel
2012-05-01
We have developed a three-dimensional potential energy surface for the lowest triplet state of the Rb(2)He complex. A global analytic fit is provided as in the supplementary material [see supplementary material at http://dx.doi.org/10.1063/1.4709433 for the corresponding Fortran code]. This surface is used to perform quantum scattering calculations of (4)He and (3)He colliding with (87)Rb(2) in the partial wave J = 0 at low and ultralow energies. For the heavier helium isotope, the computed vibrational relaxation probabilities show a broad and strong shape resonance for a collisional energy of 0.15 K and a narrow Feshbach resonance at about 17 K for all initial Rb(2) vibrational states studied. The broad resonance corresponds to an efficient relaxation mechanism that does not occur when (3)He is the colliding partner. The Feshbach resonance observed at higher collisional energy is robust with respect to the isotopic substitution. However, its effect on the vibrational relaxation mechanism is faint for both isotopes. PMID:22583230
Cell therapy for full-thickness wounds: are fetal dermal cells a potential source?
Akershoek, J J; Vlig, M; Talhout, W; Boekema, B K H L; Richters, C D; Beelen, R H J; Brouwer, K M; Middelkoop, E; Ulrich, M M W
2016-04-01
The application of autologous dermal fibroblasts has been shown to improve burn wound healing. However, a major hurdle is the availability of sufficient healthy skin as a cell source. We investigated fetal dermal cells as an alternative source for cell-based therapy for skin regeneration. Human (hFF), porcine fetal (pFF) or autologous dermal fibroblasts (AF) were seeded in a collagen-elastin substitute (Novomaix, NVM), which was applied in combination with an autologous split thickness skin graft (STSG) to evaluate the effects of these cells on wound healing in a porcine excisional wound model. Transplantation of wounds with NVM+hFF showed an increased influx of inflammatory cells (e.g., neutrophils, macrophages, CD4(+) and CD8(+) lymphocytes) compared to STSG, acellular NVM (Acell-NVM) and NVM+AF at post-surgery days 7 and/or 14. Wounds treated with NVM+pFF presented only an increase in CD8(+) lymphocyte influx. Furthermore, reduced alpha-smooth muscle actin (αSMA) expression in wound areas and reduced contraction of the wounds was observed with NVM+AF compared to Acell-NVM. Xenogeneic transplantation of NVM+hFF increased αSMA expression in wounds compared to NVM+AF. An improved scar quality was observed for wounds treated with NVM+AF compared to Acell-NVM, NVM+hFF and NVM+pFF at day 56. In conclusion, application of autologous fibroblasts improved the overall outcome of wound healing in comparison to fetal dermal cells and Acell-NVM, whereas application of fetal dermal fibroblasts in NVM did not improve wound healing of full-thickness wounds in a porcine model. Although human fetal dermal cells demonstrated an increased immune response, this did not seem to affect scar quality.
DYNA2D96. Explicit 2-D Hydrodynamic FEM Program
Whirley, R.G.
1992-04-01
DYNA2D is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.
Isegawa, Miho; Liu, Fengyi; Maeda, Satoshi; Morokuma, Keiji
2014-10-21
We report reaction paths starting from N({sup 2}D) + H{sub 2}O for doublet spin states, D{sub 0} and D{sub 1}. The potential energy surfaces are explored in an automated fashion using the global reaction route mapping strategy. The critical points and reaction paths have been fully optimized at the complete active space second order perturbation theory level taking all valence electrons in the active space. In addition to direct dissociation pathways that would be dominant, three roaming processes, two roaming dissociation, and one roaming isomerization: (1) H{sub 2}ON → H–O(H)N → H–HON → NO({sup 2}Π) + H{sub 2}, (2) cis-HNOH → HNO–H → H–HNO → NO + H{sub 2}, (3) H{sub 2}NO → H–HNO → HNO–H → trans-HNOH, are confirmed on the D{sub 0} surface.
2001-01-31
This software reduces the data from two-dimensional kSA MOS program, k-Space Associates, Ann Arbor, MI. Initial MOS data is recorded without headers in 38 columns, with one row of data per acquisition per lase beam tracked. The final MOSS 2d data file is reduced, graphed, and saved in a tab-delimited column format with headers that can be plotted in any graphing software.
De Vrieze, Jo; Smet, Davey; Klok, Jacob; Colsen, Joop; Angenent, Largus T; Vlaeminck, Siegfried E
2016-10-01
The conventional treatment of municipal wastewater by means of activated sludge is typically energy demanding. Here, the potential benefits of: (1) the optimization of mesophilic digestion; and (2) transitioning to thermophilic sludge digestion in three wastewater treatment plants (Tilburg-Noord, Land van Cuijk and Bath) in the Netherlands is evaluated, including a full-scale trial validation in Bath. In Tilburg-Noord, thermophilic sludge digestion covered the energy requirements of the plant (102%), whereas 111% of sludge operational treatment costs could be covered in Bath. Thermophilic sludge digestion also resulted in a strong increase in nutrient release. The potential for nutrient recovery was evaluated via: (1) stripping/absorption of ammonium; (2) autotrophic removal of ammonium via partial nitritation/anammox; and (3) struvite precipitation. This research shows that optimization of sludge digestion may lead to a strong increase in energy recovery, sludge treatment costs reduction, and the potential for advanced nutrient management in full-scale sewage treatment plants.
WFR-2D: an analytical model for PWAS-generated 2D ultrasonic guided wave propagation
NASA Astrophysics Data System (ADS)
Shen, Yanfeng; Giurgiutiu, Victor
2014-03-01
This paper presents WaveFormRevealer 2-D (WFR-2D), an analytical predictive tool for the simulation of 2-D ultrasonic guided wave propagation and interaction with damage. The design of structural health monitoring (SHM) systems and self-aware smart structures requires the exploration of a wide range of parameters to achieve best detection and quantification of certain types of damage. Such need for parameter exploration on sensor dimension, location, guided wave characteristics (mode type, frequency, wavelength, etc.) can be best satisfied with analytical models which are fast and efficient. The analytical model was constructed based on the exact 2-D Lamb wave solution using Bessel and Hankel functions. Damage effects were inserted in the model by considering the damage as a secondary wave source with complex-valued directivity scattering coefficients containing both amplitude and phase information from wave-damage interaction. The analytical procedure was coded with MATLAB, and a predictive simulation tool called WaveFormRevealer 2-D was developed. The wave-damage interaction coefficients (WDICs) were extracted from harmonic analysis of local finite element model (FEM) with artificial non-reflective boundaries (NRB). The WFR-2D analytical simulation results were compared and verified with full scale multiphysics finite element models and experiments with scanning laser vibrometer. First, Lamb wave propagation in a pristine aluminum plate was simulated with WFR-2D, compared with finite element results, and verified by experiments. Then, an inhomogeneity was machined into the plate to represent damage. Analytical modeling was carried out, and verified by finite element simulation and experiments. This paper finishes with conclusions and suggestions for future work.
NASA Technical Reports Server (NTRS)
Jones, Henry E.
1997-01-01
A study of the full-potential modeling of a blade-vortex interaction was made. A primary goal of this study was to investigate the effectiveness of the various methods of modeling the vortex. The model problem restricts the interaction to that of an infinite wing with an infinite line vortex moving parallel to its leading edge. This problem provides a convenient testing ground for the various methods of modeling the vortex while retaining the essential physics of the full three-dimensional interaction. A full-potential algorithm specifically tailored to solve the blade-vortex interaction (BVI) was developed to solve this problem. The basic algorithm was modified to include the effect of a vortex passing near the airfoil. Four different methods of modeling the vortex were used: (1) the angle-of-attack method, (2) the lifting-surface method, (3) the branch-cut method, and (4) the split-potential method. A side-by-side comparison of the four models was conducted. These comparisons included comparing generated velocity fields, a subcritical interaction, and a critical interaction. The subcritical and critical interactions are compared with experimentally generated results. The split-potential model was used to make a survey of some of the more critical parameters which affect the BVI.
Realistic and efficient 2D crack simulation
NASA Astrophysics Data System (ADS)
Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek
2010-04-01
Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.
Three-bosons in 2D with a magnetic field
NASA Astrophysics Data System (ADS)
Rittenhouse, Seth; Johnson, Brad; Wray, Andrew; D'Incao, Jose
2016-05-01
Systems of interacting particles in reduced dimensions in the presence of external fields can exhibit a number of surprising behaviors, for instance the emergence of the fractional quantum Hall effect. Examining few-body interactions and effects can lead to significant insights within these systems. In this talk we examine a system of three bosons confined to two dimensions in the presence of a perpendicular magnetic field within the framework of the adiabatic hyperspherical method. For the case of zero-range, regularized pseudo-potential interactions, we find that the system is nearly separable in hyperspherical coordinates and that, away from a set of narrow avoided crossings, the full energy eigenspectrum as a function of the 2D s-wave scattering length is well described by ignoring coupling between adiabatic hyperradial potentials. In the case of weak attractive or repulsive interactions, we find the lowest three-body energy states exhibit even/odd parity oscillations as a function of total internal 2D angular momentum and that for weak repulsive interactions, the universal lowest energy interacting state has an internal angular momentum of M=3. We also discuss the effect of including finite range and higher partial-wave interactions.
Georgi, Howard; Kats, Yevgeny
2008-09-26
We discuss what can be learned about unparticle physics by studying simple quantum field theories in one space and one time dimension. We argue that the exactly soluble 2D theory of a massless fermion coupled to a massive vector boson, the Sommerfield model, is an interesting analog of a Banks-Zaks model, approaching a free theory at high energies and a scale-invariant theory with nontrivial anomalous dimensions at low energies. We construct a toy standard model coupling to the fermions in the Sommerfield model and study how the transition from unparticle behavior at low energies to free particle behavior at high energies manifests itself in interactions with the toy standard model particles.
De Vrieze, Jo; Smet, Davey; Klok, Jacob; Colsen, Joop; Angenent, Largus T; Vlaeminck, Siegfried E
2016-10-01
The conventional treatment of municipal wastewater by means of activated sludge is typically energy demanding. Here, the potential benefits of: (1) the optimization of mesophilic digestion; and (2) transitioning to thermophilic sludge digestion in three wastewater treatment plants (Tilburg-Noord, Land van Cuijk and Bath) in the Netherlands is evaluated, including a full-scale trial validation in Bath. In Tilburg-Noord, thermophilic sludge digestion covered the energy requirements of the plant (102%), whereas 111% of sludge operational treatment costs could be covered in Bath. Thermophilic sludge digestion also resulted in a strong increase in nutrient release. The potential for nutrient recovery was evaluated via: (1) stripping/absorption of ammonium; (2) autotrophic removal of ammonium via partial nitritation/anammox; and (3) struvite precipitation. This research shows that optimization of sludge digestion may lead to a strong increase in energy recovery, sludge treatment costs reduction, and the potential for advanced nutrient management in full-scale sewage treatment plants. PMID:27423372
NASA Astrophysics Data System (ADS)
Benjamini, Dan; Basser, Peter J.
2016-10-01
Measuring multidimensional (e.g., 2D) relaxation spectra in NMR and MRI clinical applications is a holy grail of the porous media and biomedical MR communities. The main bottleneck is the inversion of Fredholm integrals of the first kind, an ill-conditioned problem requiring large amounts of data to stabilize a solution. We suggest a novel experimental design and processing framework to accelerate and improve the reconstruction of such 2D spectra that uses a priori information from the 1D projections of spectra, or marginal distributions. These 1D marginal distributions provide powerful constraints when 2D spectra are reconstructed, and their estimation requires an order of magnitude less data than a conventional 2D approach. This marginal distributions constrained optimization (MADCO) methodology is demonstrated here with a polyvinylpyrrolidone-water phantom that has 3 distinct peaks in the 2D D-T1 space. The stability, sensitivity to experimental parameters, and accuracy of this new approach are compared with conventional methods by serially subsampling the full data set. While the conventional, unconstrained approach performed poorly, the new method had proven to be highly accurate and robust, only requiring a fraction of the data. Additionally, synthetic T1 -T2 data are presented to explore the effects of noise on the estimations, and the performance of the proposed method with a smooth and realistic 2D spectrum. The proposed framework is quite general and can also be used with a variety of 2D MRI experiments (D-T2,T1 -T2, D -D, etc.), making these potentially feasible for preclinical and even clinical applications for the first time.
Benjamini, Dan; Basser, Peter J
2016-10-01
Measuring multidimensional (e.g., 2D) relaxation spectra in NMR and MRI clinical applications is a holy grail of the porous media and biomedical MR communities. The main bottleneck is the inversion of Fredholm integrals of the first kind, an ill-conditioned problem requiring large amounts of data to stabilize a solution. We suggest a novel experimental design and processing framework to accelerate and improve the reconstruction of such 2D spectra that uses a priori information from the 1D projections of spectra, or marginal distributions. These 1D marginal distributions provide powerful constraints when 2D spectra are reconstructed, and their estimation requires an order of magnitude less data than a conventional 2D approach. This marginal distributions constrained optimization (MADCO) methodology is demonstrated here with a polyvinylpyrrolidone-water phantom that has 3 distinct peaks in the 2D D-T1 space. The stability, sensitivity to experimental parameters, and accuracy of this new approach are compared with conventional methods by serially subsampling the full data set. While the conventional, unconstrained approach performed poorly, the new method had proven to be highly accurate and robust, only requiring a fraction of the data. Additionally, synthetic T1-T2 data are presented to explore the effects of noise on the estimations, and the performance of the proposed method with a smooth and realistic 2D spectrum. The proposed framework is quite general and can also be used with a variety of 2D MRI experiments (D-T2,T1-T2,D-D, etc.), making these potentially feasible for preclinical and even clinical applications for the first time. PMID:27543810
Lu, Fei; Wang, Xiaoke; Han, Bing; Ouyang, Zhiyun; Duan, Xiaonan; Zheng, Hua
2010-04-01
Based on the carbon-nitrogen cycles and greenhouse gas (GHG) mitigation and emission processes related to straw return and burning, a compound greenhouse gas budget model, the "Straw Return and Burning Model" (SRBM), was constructed to estimate the net mitigation potential of straw return to the soil in China. As a full GHG budget model, the SRBM addressed the following five processes: (1) soil carbon sequestration, (2) mitigation of synthetic N fertilizer substitution, (3) methane emission from rice paddies, (4) additional fossil fuel use for straw return, and (5) CH4 and N2O emissions from straw burning in the fields. Two comparable scenarios were created to reflect different degrees of implementation for straw return and straw burning. With GHG emissions and mitigation effects of the five processes converted into global warming potential (GWP), the net GHG mitigation was estimated. We concluded that (1) when the full greenhouse gas budget is considered, the net mitigation potential of straw return differs from that when soil carbon sequestration is considered alone; (2) implementation of straw return across a larger area of cropland in 10 provinces (i.e., Shanghai, Jiangsu, Zhejiang, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, and Hainan) will increase net GHG emission; (3) if straw return is promoted as a feasible mitigation measure in the remaining provinces, the total net mitigation potential before soil organic carbon (SOC) saturation will be 71.89 Tg CO2 equivalent (eqv)/yr, which is equivalent to 1.733% of the annual carbon emission from fossil fuel use in China in 2003; (4) after SOC saturation, only 13 of 21 provinces retain a relatively small but permanent net mitigation potential, while in the others the net GHG mitigation potential will gradually diminish; and (5) the major obstacle to the feasibility or permanence of straw return as a mitigation measure is the increased CH4 emission from rice paddies. The paper also suggests that comparable
Van der Waals stacked 2D layered materials for optoelectronics
NASA Astrophysics Data System (ADS)
Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.
2016-06-01
The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.
NASA Astrophysics Data System (ADS)
Yarkony, David
2015-03-01
The construction of fit single state potential energy surfaces (PESs), analytic representations of ab initio electronic energies and energy gradients, is now well established. These single state PESs, which are essential for accurate quantum dynamics and have found wide application in more approximate quasi-classical treatments, have revolutionized adiabatic dynamics. The situation for nonadiabatic processes involving dissociative and large amplitude motion is less sanguine. In these cases, compared to single electronic state dynamics, both the electronic structure data and the representation are more challenging to determine. We describe the recent development and applications of algorithms that enable description of multiple adiabatic electronic potential energy surfaces coupled by conical intersections in their full dimensionality using coupled quasi-diabatic states. These representations are demonstrably quasi-diabatic, provide accurate representations of conical intersection seams and can smooth out the discontinuities in electronic structure energies due to changing active orbital spaces that routinely afflict global multistate representations.
Communication: A benchmark-quality, full-dimensional ab initio potential energy surface for Ar-HOCO
Conte, Riccardo E-mail: jmbowma@emory.edu; Bowman, Joel M. E-mail: jmbowma@emory.edu; Houston, Paul L.
2014-04-21
A full-dimensional, global ab initio potential energy surface (PES) for the Ar-HOCO system is presented. The PES consists of a previous intramolecular ab initio PES for HOCO [J. Li, C. Xie, J. Ma, Y. Wang, R. Dawes, D. Xie, J. M. Bowman, and H. Guo, J. Phys. Chem. A 116, 5057 (2012)], plus a new permutationally invariant interaction potential based on fitting 12 432 UCCSD(T)-F12a/aVDZ counterpoise-corrected energies. The latter has a total rms fitting error of about 25 cm{sup −1} for fitted interaction energies up to roughly 12 000 cm{sup −1}. Two additional fits are presented. One is a novel very compact permutational invariant representation, which contains terms only involving the Ar-atom distances. The rms fitting error for this fit is 193 cm{sup −1}. The other fit is the widely used pairwise one. The pairwise fit to the entire data set has an rms fitting error of 427 cm{sup −1}. All of these potentials are used in preliminary classical trajectory calculations of energy transfer with a focus on comparisons with the results using the benchmark potential.
Niu, Zhongzheng; Xie, Chuanbo; Wen, Xiaozhong; Tian, Fuying; Yuan, Shixin; Jia, Deqin; Chen, Wei-Qing
2016-01-01
It is well documented that maternal exposure to second-hand smoke (SHS) during pregnancy causes low birth weight (LBW), but its mechanism remains unknown. This study explored the potential pathways. We enrolled 195 pregnant women who delivered full-term LBW newborns, and 195 who delivered full-term normal birth weight newborns as the controls. After controlling for maternal age, education level, family income, pre-pregnant body mass index, newborn gender and gestational age, logistic regression analysis revealed that LBW was significantly and positively associated with maternal exposure to SHS during pregnancy, lower placental weight, TNF-α and IL-1β, and that SHS exposure was significantly associated with lower placental weight, TNF-α and IL-1β. Structural equation modelling identified two plausible pathways by which maternal exposure to SHS during pregnancy might cause LBW. First, SHS exposure induced the elevation of TNF-α, which might directly increase the risk of LBW by transmission across the placenta. Second, SHS exposure first increased maternal secretion of IL-1β and TNF-α, which then triggered the secretion of VCAM-1; both TNF-α and VCAM-1 were significantly associated with lower placental weight, thus increasing the risk of LBW. In conclusion, maternal exposure to SHS during pregnancy may lead to LBW through the potential pathways of maternal inflammation and lower placental weight. PMID:27126191
Niu, Zhongzheng; Xie, Chuanbo; Wen, Xiaozhong; Tian, Fuying; Yuan, Shixin; Jia, Deqin; Chen, Wei-Qing
2016-01-01
It is well documented that maternal exposure to second-hand smoke (SHS) during pregnancy causes low birth weight (LBW), but its mechanism remains unknown. This study explored the potential pathways. We enrolled 195 pregnant women who delivered full-term LBW newborns, and 195 who delivered full-term normal birth weight newborns as the controls. After controlling for maternal age, education level, family income, pre-pregnant body mass index, newborn gender and gestational age, logistic regression analysis revealed that LBW was significantly and positively associated with maternal exposure to SHS during pregnancy, lower placental weight, TNF-α and IL-1β, and that SHS exposure was significantly associated with lower placental weight, TNF-α and IL-1β. Structural equation modelling identified two plausible pathways by which maternal exposure to SHS during pregnancy might cause LBW. First, SHS exposure induced the elevation of TNF-α, which might directly increase the risk of LBW by transmission across the placenta. Second, SHS exposure first increased maternal secretion of IL-1β and TNF-α, which then triggered the secretion of VCAM-1; both TNF-α and VCAM-1 were significantly associated with lower placental weight, thus increasing the risk of LBW. In conclusion, maternal exposure to SHS during pregnancy may lead to LBW through the potential pathways of maternal inflammation and lower placental weight. PMID:27126191
Full-dimensional vibrational calculations for H5O2+ using an ab initio potential energy surface
NASA Astrophysics Data System (ADS)
McCoy, Anne B.; Huang, Xinchuan; Carter, Stuart; Landeweer, Marc Y.; Bowman, Joel M.
2005-02-01
We report quantum diffusion Monte Carlo (DMC) and variational calculations in full dimensionality for selected vibrational states of H5O2+ using a new ab initio potential energy surface [X. Huang, B. Braams, and J. M. Bowman, J. Chem. Phys. 122, 044308 (2005)]. The energy and properties of the zero-point state are focused on in the rigorous DMC calculations. OH-stretch fundamentals are also calculated using "fixed-node" DMC calculations and variationally using two versions of the code MULTIMODE. These results are compared with infrared multiphoton dissociation measurements of Yeh et al. [L. I. Yeh, M. Okumura, J. D. Myers, J. M. Price, and Y. T. Lee, J. Chem. Phys. 91, 7319 (1989)]. Some preliminary results for the energies of several modes of the shared hydrogen are also reported.
NASA Technical Reports Server (NTRS)
Farrell, C. A.
1982-01-01
A fast, reliable computer code is described for calculating the flow field about a cascade of arbitrary two dimensional airfoils. The method approximates the three dimensional flow in a turbomachinery blade row by correcting for stream tube convergence and radius change in the throughflow direction. A fully conservative solution of the full potential equation is combined with the finite volume technique on a body-fitted periodic mesh, with an artificial density imposed in the transonic region to insure stability and the capture of shock waves. The instructions required to set up and use the code are included. The name of the code is QSONIC. A numerical example is also given to illustrate the output of the program.
Borkar, Roshan M; Bhandi, Murali Mohan; Dubey, Ajay P; Ganga Reddy, V; Komirishetty, Prashanth; Nandekar, Prajwal P; Sangamwar, Abhay T; Kamal, Ahmed; Banerjee, Sanjay K; Srinivas, R
2016-10-01
The aim of the present study was to evaluate the contribution of metabolites to drug-drug interaction and drug-herb interaction using the inhibition of CYP2D6 and CYP3A4 by metoprolol (MET) and its metabolites. The peak concentrations of unbound plasma concentration of MET, α-hydroxy metoprolol (HM), O-desmethyl metoprolol (ODM) and N-desisopropyl metoprolol (DIM) were 90.37 ± 2.69, 33.32 ± 1.92, 16.93 ± 1.70 and 7.96 ± 0.94 ng/mL, respectively. The metabolites identified, HM and ODM, had a ratio of metabolic area under the concentration-time curve (AUC) to parent AUC of ≥0.25 when either total or unbound concentration of metabolite was considered. In vitro CYP2D6 and CYP3A4 inhibition by MET, HM and ODM study revealed that MET, HM and ODM were not inhibitors of CYP3A4-catalyzed midazolam metabolism and CYP2D6-catalyzed dextromethorphan metabolism. However, DIM only met the criteria of >10% of the total drug related material and <25% of the parent using unbound concentrations. If CYP inhibition testing is solely based on metabolite exposure, DIM metabolite would probably not be considered. However, the present study has demonstrated that DIM contributes significantly to in vitro drug-drug interaction. Copyright © 2016 John Wiley & Sons, Ltd.
A full-dimensional analytical potential energy surface for the F+CH4→HF + CH3 reaction
NASA Astrophysics Data System (ADS)
Yang, Chuan-Lu; Wang, Mei-Shan; Liu, Wen-Wang; Zhang, Zhi-Hong; Ma, Xiao-Guang
2013-06-01
A full-dimensional analytical potential energy surface (APES) for the F + CH4 →HF + CH3 reaction is developed based on 7127 ab initio energy points at the unrestricted coupled-cluster with single, double, and perturbative triple excitations. The correlation-consistent polarized triple-split valence basis set is used. The APES is represented with a many-body expansion containing 239 parameters determined by the least square fitting method. The two-body terms of the APES are fitted by potential energy curves with multi-reference configuration interaction, which can describe the diatomic molecules (CH, H2, HF, and CF) accurately. It is found that the APES can reproduce the geometry and vibrational frequencies of the saddle point better than those available in the literature. The rate constants based on the present APES support the experimental results of Moore et al. [Int. J. Chem. Kin. 26, 813 (1994)]. The analytical first-order derivation of energy is also provided, making the present APES convenient and efficient for investigating the title reaction with quasiclassical trajectory calculations.
NASA Astrophysics Data System (ADS)
Ono, Tomoya; Heide, Marcus; Atodiresei, Nicolae; Baumeister, Paul; Tsukamoto, Shigeru; Blügel, Stefan
2010-11-01
We have developed an efficient computational scheme utilizing the real-space finite-difference formalism and the projector augmented-wave (PAW) method to perform precise first-principles electronic-structure simulations based on the density-functional theory for systems containing transition metals with a modest computational effort. By combining the advantages of the time-saving double-grid technique and the Fourier-filtering procedure for the projectors of pseudopotentials, we can overcome the egg box effect in the computations even for first-row elements and transition metals, which is a problem of the real-space finite-difference formalism. In order to demonstrate the potential power in terms of precision and applicability of the present scheme, we have carried out simulations to examine several bulk properties and structural energy differences between different bulk phases of transition metals and have obtained excellent agreement with the results of other precise first-principles methods such as a plane-wave-based PAW method and an all-electron full-potential linearized augmented plane-wave (FLAPW) method.
VizieR Online Data Catalog: The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003)
NASA Astrophysics Data System (ADS)
Colless, M.; Dalton, G.; Maddox, S.; Sutherland, W.; Norberg, P.; Cole, S.; Bland-Hawthorn, J.; Bridges, T.; Cannon, R.; Collins, C.; Couch, W.; Cross, N.; Deeley, K.; de Propris, R.; Driver, S. P.; Efstathiou, G.; Ellis, R. S.; Frenk, C. S.; Glazebrook, K.; Jackson, C.; Lahav, O.; Lewis, I.; Lumsden, S.; Madgwick, D.; Peacock, J. A.; Peterson, B. A.; Price, I.; Seaborne, M.; Taylor, K.
2007-11-01
The 2dF Galaxy Redshift Survey (2dFGRS) is a major spectroscopic survey taking full advantage of the unique capabilities of the 2dF facility built by the Anglo-Australian Observatory. The 2dFGRS is integrated with the 2dF QSO survey (2QZ, Cat. VII/241). The 2dFGRS obtained spectra for 245591 objects, mainly galaxies, brighter than a nominal extinction-corrected magnitude limit of bJ=19.45. Reliable (quality>=3) redshifts were obtained for 221414 galaxies. The galaxies cover an area of approximately 1500 square degrees selected from the extended APM Galaxy Survey in three regions: a North Galactic Pole (NGP) strip, a South Galactic Pole (SGP) strip, and random fields scattered around the SGP strip. Redshifts are measured from spectra covering 3600-8000 Angstroms at a two-pixel resolution of 9.0 Angstrom and a median S/N of 13 per pixel. All redshift identifications are visually checked and assigned a quality parameter Q in the range 1-5; Q>=3 redshifts are 98.4% reliable and have an rms uncertainty of 85 km/s. The overall redshift completeness for Q>=3 redshifts is 91.8% but this varies with magnitude from 99% for the brightest galaxies to 90% for objects at the survey limit. The 2dFGRS data base is available on the World Wide Web at http://www.mso.anu.edu.au/2dFGRS/. (6 data files).
NASA Astrophysics Data System (ADS)
Barragán, Patricia; Pérez de Tudela, Ricardo; Qu, Chen; Prosmiti, Rita; Bowman, Joel M.
2013-07-01
Diffusion Monte Carlo (DMC) and path-integral Monte Carlo computations of the vibrational ground state and 10 K equilibrium state properties of the H_7^+/D_7^+ cations are presented, using an ab initio full-dimensional potential energy surface. The DMC zero-point energies of dissociated fragments H_5^+(D_5^+)+H2(D2) are also calculated and from these results and the electronic dissociation energy, dissociation energies, D0, of 752 ± 15 and 980 ± 14 cm-1 are reported for H_7^+ and D_7^+, respectively. Due to the known error in the electronic dissociation energy of the potential surface, these quantities are underestimated by roughly 65 cm-1. These values are rigorously determined for first time, and compared with previous theoretical estimates from electronic structure calculations using standard harmonic analysis, and available experimental measurements. Probability density distributions are also computed for the ground vibrational and 10 K state of H_7^+ and D_7^+. These are qualitatively described as a central H_3^+/D_3^+ core surrounded by "solvent" H2/D2 molecules that nearly freely rotate.
Efficient 2D MRI relaxometry using compressed sensing
NASA Astrophysics Data System (ADS)
Bai, Ruiliang; Cloninger, Alexander; Czaja, Wojciech; Basser, Peter J.
2015-06-01
Potential applications of 2D relaxation spectrum NMR and MRI to characterize complex water dynamics (e.g., compartmental exchange) in biology and other disciplines have increased in recent years. However, the large amount of data and long MR acquisition times required for conventional 2D MR relaxometry limits its applicability for in vivo preclinical and clinical MRI. We present a new MR pipeline for 2D relaxometry that incorporates compressed sensing (CS) as a means to vastly reduce the amount of 2D relaxation data needed for material and tissue characterization without compromising data quality. Unlike the conventional CS reconstruction in the Fourier space (k-space), the proposed CS algorithm is directly applied onto the Laplace space (the joint 2D relaxation data) without compressing k-space to reduce the amount of data required for 2D relaxation spectra. This framework is validated using synthetic data, with NMR data acquired in a well-characterized urea/water phantom, and on fixed porcine spinal cord tissue. The quality of the CS-reconstructed spectra was comparable to that of the conventional 2D relaxation spectra, as assessed using global correlation, local contrast between peaks, peak amplitude and relaxation parameters, etc. This result brings this important type of contrast closer to being realized in preclinical, clinical, and other applications.
Canard configured aircraft with 2-D nozzle
NASA Technical Reports Server (NTRS)
Child, R. D.; Henderson, W. P.
1978-01-01
A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.
NASA Astrophysics Data System (ADS)
Ravindran, P.; Vidya, R.; Vajeeston, P.; Kjekshus, A.; Fjellvåg, H.
2003-12-01
The development in theoretical condensed-matter science based on density-functional theory (DFT) has reached a level where it is possible, from "parameter-free" quantum mechanical calculations to obtain total energies, forces, vibrational frequencies, magnetic moments, mechanical and optical properties and so forth. The calculation of such properties are important in the analyses of experimental data and they can be predicted with a precision that is sufficient for comparison with experiments. It is almost impossible to do justice to all developments achieved by DFT because of its rapid growth. Hence, it has here been focused on a few advances, primarily from our laboratory. Unusual bonding behaviors in complex materials are conveniently explored using the combination of charge density, charge transfer, and electron-localization function along with crystal-orbital Hamilton-population analyses. It is indicated that the elastic properties of materials can reliably be predicted from DFT calculations if one takes into account the structural relaxations along with gradient corrections in the calculations. Experimental techniques have their limitations in studies of the structural stability and pressure-induced structural transitions in hydride materials whereas the present theoretical approach can be applied to reliably predict properties under extreme pressures. From the spin-polarized, relativistic full-potential calculations one can study novel materials such as ruthenates, quasi-one-dimensional oxides, and spin-, charge-, and orbital-ordering in magnetic perovskite-like oxides. The importance of orbital-polarization correction to the DFT to predict the magnetic anisotropy in transition-metal compounds and magnetic moments in lanthanides and actinides are emphasized. Apart from the full-potential treatment, proper magnetic ordering as well as structural distortions have to be taken into account to predict correctly the insulating behavior of transition-metal oxides
The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China
Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian
2016-01-01
The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology. PMID:27375513
The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China.
Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian
2016-01-01
The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology. PMID:27375513
The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China.
Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian
2016-01-01
The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology.
Alloyed 2D Metal-Semiconductor Atomic Layer Junctions.
Kim, Ah Ra; Kim, Yonghun; Nam, Jaewook; Chung, Hee-Suk; Kim, Dong Jae; Kwon, Jung-Dae; Park, Sang Won; Park, Jucheol; Choi, Sun Young; Lee, Byoung Hun; Park, Ji Hyeon; Lee, Kyu Hwan; Kim, Dong-Ho; Choi, Sung Mook; Ajayan, Pulickel M; Hahm, Myung Gwan; Cho, Byungjin
2016-03-01
Heterostructures of compositionally and electronically variant two-dimensional (2D) atomic layers are viable building blocks for ultrathin optoelectronic devices. We show that the composition of interfacial transition region between semiconducting WSe2 atomic layer channels and metallic NbSe2 contact layers can be engineered through interfacial doping with Nb atoms. WxNb1-xSe2 interfacial regions considerably lower the potential barrier height of the junction, significantly improving the performance of the corresponding WSe2-based field-effect transistor devices. The creation of such alloyed 2D junctions between dissimilar atomic layer domains could be the most important factor in controlling the electronic properties of 2D junctions and the design and fabrication of 2D atomic layer devices.
Double resonance rotational spectroscopy of CH2D+
NASA Astrophysics Data System (ADS)
Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar
2016-09-01
Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.
Alloyed 2D Metal-Semiconductor Atomic Layer Junctions.
Kim, Ah Ra; Kim, Yonghun; Nam, Jaewook; Chung, Hee-Suk; Kim, Dong Jae; Kwon, Jung-Dae; Park, Sang Won; Park, Jucheol; Choi, Sun Young; Lee, Byoung Hun; Park, Ji Hyeon; Lee, Kyu Hwan; Kim, Dong-Ho; Choi, Sung Mook; Ajayan, Pulickel M; Hahm, Myung Gwan; Cho, Byungjin
2016-03-01
Heterostructures of compositionally and electronically variant two-dimensional (2D) atomic layers are viable building blocks for ultrathin optoelectronic devices. We show that the composition of interfacial transition region between semiconducting WSe2 atomic layer channels and metallic NbSe2 contact layers can be engineered through interfacial doping with Nb atoms. WxNb1-xSe2 interfacial regions considerably lower the potential barrier height of the junction, significantly improving the performance of the corresponding WSe2-based field-effect transistor devices. The creation of such alloyed 2D junctions between dissimilar atomic layer domains could be the most important factor in controlling the electronic properties of 2D junctions and the design and fabrication of 2D atomic layer devices. PMID:26839956
Lu, Xuzhang; Zhu, Zhichao; Jiang, Lijia; Sun, Xiao; Jia, Zhuxia; Qian, Sixuan; Li, Jianyong; Ma, Lingdi
2015-01-01
Purpose: The study aimed to investigate the role of the JAK/STAT3 pathway in the matrine induced ULBP2 expression on the human chronic myelogenous leukemia K562 cells. Methods: K562 cells were cultured, and the relevant mRNA expressions were detected. Results: Matrine induced the expression of four NKG2D ligands on K562 cells, of which ULBP2 had the highest increase. After treatment with 0.8 mg/mL matrine for 24 h, the mean fluorescence intensity (MFI) of ULBP2 increased. After matrine treatment, the sensitivity of K562 cells to NK cell-mediated killing increased significantly. After treatment with 0.2, 0.5 and 0.8 mg/ mL matrine, the percentage of K562 cells killed by NK cells was significantly higher than that of untreated cells (29.2%) (P<0.05). Matrine significantly inhibit the protein expression of phosphorylated STAT 3 and JAK2. Matrine markedly inhibited the IL-6 expression of K562 cells, and antagonized the IL-6 mediated STAT3 and JAK2 phosphorylation. In addition, matrine enhanced the inhibitory effect of STAT 3 inhibitor on STAT 3 activity. The silencing of STAT expression and inhibition of STAT3 activity significantly up-regulated the ULPB2 expression. Matrine had no effect on the expression of IL-6R and gp130 on K562 cells, the mRNA expression of IL-6R and gp130 increased slightly and the sgp 130 in cell supernatant significantly increased. Conclusions: Our findings reveal IL-6 and IL-6 receptor-mediated JAK/STAT3 pathway is involved in the matrine induced up-regulation of NKG2D ligands ULBP2 on K562 cells. Matrine might inhibit IL-6 expression and then suppress the activation of IL-6 receptor-mediated JAK/STAT3 pathway. PMID:26692928
Ringe, Stefan; Oberhofer, Harald; Hille, Christoph; Matera, Sebastian; Reuter, Karsten
2016-08-01
The size-modified Poisson-Boltzmann (MPB) equation is an efficient implicit solvation model which also captures electrolytic solvent effects. It combines an account of the dielectric solvent response with a mean-field description of solvated finite-sized ions. We present a general solution scheme for the MPB equation based on a fast function-space-oriented Newton method and a Green's function preconditioned iterative linear solver. In contrast to popular multigrid solvers, this approach allows us to fully exploit specialized integration grids and optimized integration schemes. We describe a corresponding numerically efficient implementation for the full-potential density-functional theory (DFT) code FHI-aims. We show that together with an additional Stern layer correction the DFT+MPB approach can describe the mean activity coefficient of a KCl aqueous solution over a wide range of concentrations. The high sensitivity of the calculated activity coefficient on the employed ionic parameters thereby suggests to use extensively tabulated experimental activity coefficients of salt solutions for a systematic parametrization protocol. PMID:27323006
NASA Astrophysics Data System (ADS)
Nabok, Dmitrii; Gulans, Andris; Draxl, Claudia
2016-07-01
The G W approach of many-body perturbation theory has become a common tool for calculating the electronic structure of materials. However, with increasing number of published results, discrepancies between the values obtained by different methods and codes become more and more apparent. For a test set of small- and wide-gap semiconductors, we demonstrate how to reach the numerically best electronic structure within the framework of the full-potential linearized augmented plane-wave (FLAPW) method. We first evaluate the impact of local orbitals in the Kohn-Sham eigenvalue spectrum of the underlying starting point. The role of the basis-set quality is then further analyzed when calculating the G0W0 quasiparticle energies. Our results, computed with the exciting code, are compared to those obtained using the projector-augmented plane-wave formalism, finding overall good agreement between both methods. We also provide data produced with a typical FLAPW basis set as a benchmark for other G0W0 implementations.
Ringe, Stefan; Oberhofer, Harald; Hille, Christoph; Matera, Sebastian; Reuter, Karsten
2016-08-01
The size-modified Poisson-Boltzmann (MPB) equation is an efficient implicit solvation model which also captures electrolytic solvent effects. It combines an account of the dielectric solvent response with a mean-field description of solvated finite-sized ions. We present a general solution scheme for the MPB equation based on a fast function-space-oriented Newton method and a Green's function preconditioned iterative linear solver. In contrast to popular multigrid solvers, this approach allows us to fully exploit specialized integration grids and optimized integration schemes. We describe a corresponding numerically efficient implementation for the full-potential density-functional theory (DFT) code FHI-aims. We show that together with an additional Stern layer correction the DFT+MPB approach can describe the mean activity coefficient of a KCl aqueous solution over a wide range of concentrations. The high sensitivity of the calculated activity coefficient on the employed ionic parameters thereby suggests to use extensively tabulated experimental activity coefficients of salt solutions for a systematic parametrization protocol.
Graphene based 2D-materials for supercapacitors
NASA Astrophysics Data System (ADS)
Palaniselvam, Thangavelu; Baek, Jong-Beom
2015-09-01
Ever-increasing energy demands and the depletion of fossil fuels are compelling humanity toward the development of suitable electrochemical energy conversion and storage devices to attain a more sustainable society with adequate renewable energy and zero environmental pollution. In this regard, supercapacitors are being contemplated as potential energy storage devices to afford cleaner, environmentally friendly energy. Recently, a great deal of attention has been paid to two-dimensional (2D) nanomaterials, including 2D graphene and its inorganic analogues (transition metal double layer hydroxides, chalcogenides, etc), as potential electrodes for the development of supercapacitors with high electrochemical performance. This review provides an overview of the recent progress in using these graphene-based 2D materials as potential electrodes for supercapacitors. In addition, future research trends including notable challenges and opportunities are also discussed.
Perspectives for spintronics in 2D materials
NASA Astrophysics Data System (ADS)
Han, Wei
2016-03-01
The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.
NASA Astrophysics Data System (ADS)
Cho, Young-Sang; Le Roy, Robert
2014-06-01
CH^+ has been a species of interest since the dawn of molecular astrophysics,and it is an important intermediate in combustion processes. In the domain of `conventional' spectroscopy there have been a number of studies of low v' and v" portions of the A ^1Π-X ^1Σ^+ band system of various isotopologues, and Amano recently reported microwave measurements of the ground-state R(0) lines of 12CH^+, 13CH^+ and 12CD^+. used photodissociation spectroscopy to observe transitions to very high-J' tunneling-predissociation levels (shape resonances) involving v(A)=0-10, for many of which they also measured the photo-fragment kinetic energy release. More recently Hechtfischer et al. used photodissociation spectroscopy of `Feschbach resonance' levels at very high v'(A) and low J' to obtain the first direct measurement of the 12CH^+ dissociation energy with near-spectroscopic accuracy (± 1.1 cm-1). However, to date, all analyses of the data for this system had been performed using traditional band-constant or Dunham-expansion fits to data for the lowest vibrational levels, and there have been no attempts to combine the `conventional' low-v data with the high-J' and high-v' photodissociation data in a single treatment. The present work has addressed this problem by performing a Direct-Potential-Fit (DPF) analysis that obtains full analytic potential energy functions for the X ^1Σ^+ and A ^1Π states of CH^+ that are able to account for all of the available data (on average) within their uncertainties. A.E. Douglas and G. Herzberg, Astrophys. J. 94, 381 (1941). T. Amano, Astrophys. J. Lett. {716}, L1 (2010) H. Helm, P.C. Crosby, M.M. Graff and J.T. Mosley, Phys. Rev. A 25, 304 (1982) U. Hechtfischer and C. J. Williams, M. Lange, J. Linkemann, D. Schwalm, R. Wester, A. Wolf and D. Zajfman, J.Chem.Phys. 117, 8754 (2002). H.S.P. Müller, Astron. Astrophys. 514, L7 (2010)
NASA Astrophysics Data System (ADS)
Gulans, Andris; Kontur, Stefan; Meisenbichler, Christian; Nabok, Dmitrii; Pavone, Pasquale; Rigamonti, Santiago; Sagmeister, Stephan; Werner, Ute; Draxl, Claudia
2014-09-01
Linearized augmented planewave methods are known as the most precise numerical schemes for solving the Kohn-Sham equations of density-functional theory (DFT). In this review, we describe how this method is realized in the all-electron full-potential computer package, exciting. We emphasize the variety of different related basis sets, subsumed as (linearized) augmented planewave plus local orbital methods, discussing their pros and cons and we show that extremely high accuracy (microhartrees) can be achieved if the basis is chosen carefully. As the name of the code suggests, exciting is not restricted to ground-state calculations, but has a major focus on excited-state properties. It includes time-dependent DFT in the linear-response regime with various static and dynamical exchange-correlation kernels. These are preferably used to compute optical and electron-loss spectra for metals, molecules and semiconductors with weak electron-hole interactions. exciting makes use of many-body perturbation theory for charged and neutral excitations. To obtain the quasi-particle band structure, the GW approach is implemented in the single-shot approximation, known as G0W0. Optical absorption spectra for valence and core excitations are handled by the solution of the Bethe-Salpeter equation, which allows for the description of strongly bound excitons. Besides these aspects concerning methodology, we demonstrate the broad range of possible applications by prototypical examples, comprising elastic properties, phonons, thermal-expansion coefficients, dielectric tensors and loss functions, magneto-optical Kerr effect, core-level spectra and more.
Gulans, Andris; Kontur, Stefan; Meisenbichler, Christian; Nabok, Dmitrii; Pavone, Pasquale; Rigamonti, Santiago; Sagmeister, Stephan; Werner, Ute; Draxl, Claudia
2014-09-10
Linearized augmented planewave methods are known as the most precise numerical schemes for solving the Kohn-Sham equations of density-functional theory (DFT). In this review, we describe how this method is realized in the all-electron full-potential computer package, exciting. We emphasize the variety of different related basis sets, subsumed as (linearized) augmented planewave plus local orbital methods, discussing their pros and cons and we show that extremely high accuracy (microhartrees) can be achieved if the basis is chosen carefully. As the name of the code suggests, exciting is not restricted to ground-state calculations, but has a major focus on excited-state properties. It includes time-dependent DFT in the linear-response regime with various static and dynamical exchange-correlation kernels. These are preferably used to compute optical and electron-loss spectra for metals, molecules and semiconductors with weak electron-hole interactions. exciting makes use of many-body perturbation theory for charged and neutral excitations. To obtain the quasi-particle band structure, the GW approach is implemented in the single-shot approximation, known as G(0)W(0). Optical absorption spectra for valence and core excitations are handled by the solution of the Bethe-Salpeter equation, which allows for the description of strongly bound excitons. Besides these aspects concerning methodology, we demonstrate the broad range of possible applications by prototypical examples, comprising elastic properties, phonons, thermal-expansion coefficients, dielectric tensors and loss functions, magneto-optical Kerr effect, core-level spectra and more. PMID:25135665
Azam, Faizul; Singh, Satendra; Khokhra, Sukhbir Lal; Prakash, Om
2007-01-01
Objective: A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Methods: Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2′-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results: All the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2′-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent. Conclusion: The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases. PMID:17565517
Simulating MEMS Chevron Actuator for Strain Engineering 2D Materials
NASA Astrophysics Data System (ADS)
Vutukuru, Mounika; Christopher, Jason; Bishop, David; Swan, Anna
2D materials pose an exciting paradigm shift in the world of electronics. These crystalline materials have demonstrated high electric and thermal conductivities and tensile strength, showing great potential as the new building blocks of basic electronic circuits. However, strain engineering 2D materials for novel devices remains a difficult experimental feat. We propose the integration of 2D materials with MEMS devices to investigate the strain dependence on material properties such as electrical and thermal conductivity, refractive index, mechanical elasticity, and band gap. MEMS Chevron actuators, provides the most accessible framework to study strain in 2D materials due to their high output force displacements for low input power. Here, we simulate Chevron actuators on COMSOL to optimize actuator design parameters and accurately capture the behavior of the devices while under the external force of a 2D material. Through stationary state analysis, we analyze the response of the device through IV characteristics, displacement and temperature curves. We conclude that the simulation precisely models the real-world device through experimental confirmation, proving that the integration of 2D materials with MEMS is a viable option for constructing novel strain engineered devices. The authors acknowledge support from NSF DMR1411008.
Staring 2-D hadamard transform spectral imager
Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.
2006-02-07
A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.
2D Quantum Mechanical Study of Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, B.; Kwak, Dochan (Technical Monitor)
2000-01-01
With the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density-gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions and oxide tunneling are treated on an equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. We present the results of our simulations of MIT 25, 50 and 90 nm "well-tempered" MOSFETs and compare them to those of classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. Surprisingly, the self-consistent potential profile shows lower injection barrier in the channel in quantum case. These results are qualitatively consistent with ID Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and subthreshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.
Internal Photoemission Spectroscopy of 2-D Materials
NASA Astrophysics Data System (ADS)
Nguyen, Nhan; Li, Mingda; Vishwanath, Suresh; Yan, Rusen; Xiao, Shudong; Xing, Huili; Cheng, Guangjun; Hight Walker, Angela; Zhang, Qin
Recent research has shown the great benefits of using 2-D materials in the tunnel field-effect transistor (TFET), which is considered a promising candidate for the beyond-CMOS technology. The on-state current of TFET can be enhanced by engineering the band alignment of different 2D-2D or 2D-3D heterostructures. Here we present the internal photoemission spectroscopy (IPE) approach to determine the band alignments of various 2-D materials, in particular SnSe2 and WSe2, which have been proposed for new TFET designs. The metal-oxide-2-D semiconductor test structures are fabricated and characterized by IPE, where the band offsets from the 2-D semiconductor to the oxide conduction band minimum are determined by the threshold of the cube root of IPE yields as a function of photon energy. In particular, we find that SnSe2 has a larger electron affinity than most semiconductors and can be combined with other semiconductors to form near broken-gap heterojunctions with low barrier heights which can produce a higher on-state current. The details of data analysis of IPE and the results from Raman spectroscopy and spectroscopic ellipsometry measurements will also be presented and discussed.
2D materials: to graphene and beyond.
Mas-Ballesté, Rubén; Gómez-Navarro, Cristina; Gómez-Herrero, Julio; Zamora, Félix
2011-01-01
This review is an attempt to illustrate the different alternatives in the field of 2D materials. Graphene seems to be just the tip of the iceberg and we show how the discovery of alternative 2D materials is starting to show the rest of this iceberg. The review comprises the current state-of-the-art of the vast literature in concepts and methods already known for isolation and characterization of graphene, and rationalizes the quite disperse literature in other 2D materials such as metal oxides, hydroxides and chalcogenides, and metal-organic frameworks.
Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials
NASA Technical Reports Server (NTRS)
Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.
1993-01-01
Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.
On 2D bisection method for double eigenvalue problems
Ji, X.
1996-06-01
The two-dimensional bisection method presented in (SIAM J. Matrix Anal. Appl. 13(4), 1085 (1992)) is efficient for solving a class of double eigenvalue problems. This paper further extends the 2D bisection method of full matrix cases and analyses its stability. As in a single parameter case, the 2D bisection method is very stable for the tridiagonal matrix triples satisfying the symmetric-definite condition. Since the double eigenvalue problems arise from two-parameter boundary value problems, an estimate of the discretization error in eigenpairs is also given. Some numerical examples are included. 42 refs., 1 tab.
Secretory pathways generating immunosuppressive NKG2D ligands
Baragaño Raneros, Aroa; Suarez-Álvarez, Beatriz; López-Larrea, Carlos
2014-01-01
Natural Killer Group 2 member D (NKG2D) activating receptor, present on the surface of various immune cells, plays an important role in activating the anticancer immune response by their interaction with stress-inducible NKG2D ligands (NKG2DL) on transformed cells. However, cancer cells have developed numerous mechanisms to evade the immune system via the downregulation of NKG2DL from the cell surface, including the release of NKG2DL from the cell surface in a soluble form. Here, we review the mechanisms involved in the production of soluble NKG2DL (sNKG2DL) and the potential therapeutic strategies aiming to block the release of these immunosuppressive ligands. Therapeutically enabling the NKG2D-NKG2DL interaction would promote immunorecognition of malignant cells, thus abrogating disease progression. PMID:25050215
2-d Finite Element Code Postprocessor
1996-07-15
ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forcesmore » along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.« less
Ginsparg, P.
1991-01-01
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Ginsparg, P.
1991-12-31
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Brittle damage models in DYNA2D
Faux, D.R.
1997-09-01
DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.
2D nanostructures for water purification: graphene and beyond.
Dervin, Saoirse; Dionysiou, Dionysios D; Pillai, Suresh C
2016-08-18
Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials. Recent progress in the development of nanoporous graphene based materials has generated enormous potential for water purification technologies. Progress in the development of nanoporous graphene and graphene oxide (GO) membranes, the mechanism of graphene molecular sieve action, structural design, hydrophilic nature, mechanical strength and antifouling properties and the principal challenges associated with nanopore generation are discussed in detail. Subsequently, the recent applications and performance of newly developed 2D materials such as 2D boron nitride (BN) nanosheets, graphyne, molybdenum disulfide (MoS2), tungsten chalcogenides (WS2) and titanium carbide (Ti3C2Tx) are highlighted. In addition, the challenges affecting 2D nanostructures for water purification are highlighted and their applications in the water purification industry are discussed. Though only a few 2D materials have been explored so far for water treatment applications, this emerging field of research is set to attract a great deal of attention in the near future.
Ultrafast 2D-IR spectroelectrochemistry of flavin mononucleotide
NASA Astrophysics Data System (ADS)
El Khoury, Youssef; Van Wilderen, Luuk J. G. W.; Bredenbeck, Jens
2015-06-01
We demonstrate the coupling of ultrafast two-dimensional infrared (2D-IR) spectroscopy to electrochemistry in solution and apply it to flavin mononucleotide, an important cofactor of redox proteins. For this purpose, we designed a spectroelectrochemical cell optimized for 2D-IR measurements in reflection and measured the time-dependent 2D-IR spectra of the oxidized and reduced forms of flavin mononucleotide. The data show anharmonic coupling and vibrational energy transfer between different vibrational modes in the two redox species. Such information is inaccessible with redox-controlled steady-state FTIR spectroscopy. The wide range of applications offered by 2D-IR spectroscopy, such as sub-picosecond structure determination, IR band assignment via energy transfer, disentangling reaction mixtures through band connectivity in the 2D spectra, and the measurement of solvation dynamics and chemical exchange can now be explored under controlled redox potential. The development of this technique furthermore opens new horizons for studying the dynamics of redox proteins.
Ultrafast 2D-IR spectroelectrochemistry of flavin mononucleotide.
El Khoury, Youssef; Van Wilderen, Luuk J G W; Bredenbeck, Jens
2015-06-01
We demonstrate the coupling of ultrafast two-dimensional infrared (2D-IR) spectroscopy to electrochemistry in solution and apply it to flavin mononucleotide, an important cofactor of redox proteins. For this purpose, we designed a spectroelectrochemical cell optimized for 2D-IR measurements in reflection and measured the time-dependent 2D-IR spectra of the oxidized and reduced forms of flavin mononucleotide. The data show anharmonic coupling and vibrational energy transfer between different vibrational modes in the two redox species. Such information is inaccessible with redox-controlled steady-state FTIR spectroscopy. The wide range of applications offered by 2D-IR spectroscopy, such as sub-picosecond structure determination, IR band assignment via energy transfer, disentangling reaction mixtures through band connectivity in the 2D spectra, and the measurement of solvation dynamics and chemical exchange can now be explored under controlled redox potential. The development of this technique furthermore opens new horizons for studying the dynamics of redox proteins.
Sparse radar imaging using 2D compressed sensing
NASA Astrophysics Data System (ADS)
Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying
2014-10-01
Radar imaging is an ill-posed linear inverse problem and compressed sensing (CS) has been proved to have tremendous potential in this field. This paper surveys the theory of radar imaging and a conclusion is drawn that the processing of ISAR imaging can be denoted mathematically as a problem of 2D sparse decomposition. Based on CS, we propose a novel measuring strategy for ISAR imaging radar and utilize random sub-sampling in both range and azimuth dimensions, which will reduce the amount of sampling data tremendously. In order to handle 2D reconstructing problem, the ordinary solution is converting the 2D problem into 1D by Kronecker product, which will increase the size of dictionary and computational cost sharply. In this paper, we introduce the 2D-SL0 algorithm into the reconstruction of imaging. It is proved that 2D-SL0 can achieve equivalent result as other 1D reconstructing methods, but the computational complexity and memory usage is reduced significantly. Moreover, we will state the results of simulating experiments and prove the effectiveness and feasibility of our method.
2D nanostructures for water purification: graphene and beyond.
Dervin, Saoirse; Dionysiou, Dionysios D; Pillai, Suresh C
2016-08-18
Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials. Recent progress in the development of nanoporous graphene based materials has generated enormous potential for water purification technologies. Progress in the development of nanoporous graphene and graphene oxide (GO) membranes, the mechanism of graphene molecular sieve action, structural design, hydrophilic nature, mechanical strength and antifouling properties and the principal challenges associated with nanopore generation are discussed in detail. Subsequently, the recent applications and performance of newly developed 2D materials such as 2D boron nitride (BN) nanosheets, graphyne, molybdenum disulfide (MoS2), tungsten chalcogenides (WS2) and titanium carbide (Ti3C2Tx) are highlighted. In addition, the challenges affecting 2D nanostructures for water purification are highlighted and their applications in the water purification industry are discussed. Though only a few 2D materials have been explored so far for water treatment applications, this emerging field of research is set to attract a great deal of attention in the near future. PMID:27506268
Chemical Approaches to 2D Materials.
Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang
2016-08-01
Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology. PMID:27478083
Chemical Approaches to 2D Materials.
Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang
2016-08-01
Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology.
Driever, Steven M; Kromdijk, Johannes
2013-10-01
Sustainably feeding the world's growing population in future is a great challenge and can be achieved only by increasing yield per unit land surface. Efficiency of light interception and biomass partitioning into harvestable parts (harvest index) has been improved substantially via plant breeding in modern crops. The conversion efficiency of intercepted light into biomass still holds promise for yield increase. This conversion efficiency is to a great extent constrained by the metabolic capacity of photosynthesis, defined by the characteristics of its components. Genetic manipulations are increasingly applied to lift these constraints, by improving CO2 or substrate availability for the photosynthetic carbon reduction cycle. Although these manipulations can lead to improved potential growth rates, this increase might be offset by a decrease in performance under stress conditions. In this review, we assess possible positive or negative effects of the introduction of a CO2-concentrating mechanism in C3 crop species on crop potential productivity and yield robustness.
Yang, Li-Ming; Dornfeld, Matthew; Frauenheim, Thomas; Ganz, Eric
2015-10-21
We predict a highly stable and robust atomically thin gold monolayer with a hexagonal close packed lattice stabilized by metallic bonding with contributions from strong relativistic effects and aurophilic interactions. We have shown that the framework of the Au monolayer can survive 10 ps MD annealing simulations up to 1400 K. The framework is also able to survive large motions out of the plane. Due to the smaller number of bonds per atom in the 2D layer compared to the 3D bulk we observe significantly enhanced energy per bond (0.94 vs. 0.52 eV per bond). This is similar to the increase in bond strength going from 3D diamond to 2D graphene. It is a non-magnetic metal, and was found to be the global minima in the 2D space. Phonon dispersion calculations demonstrate high kinetic stability with no negative modes. This 2D gold monolayer corresponds to the top monolayer of the bulk Au(111) face-centered cubic lattice. The close-packed lattice maximizes the aurophilic interactions. We find that the electrons are completely delocalized in the plane and behave as 2D nearly free electron gas. We hope that the present work can inspire the experimental fabrication of novel free standing 2D metal systems.
2d index and surface operators
NASA Astrophysics Data System (ADS)
Gadde, Abhijit; Gukov, Sergei
2014-03-01
In this paper we compute the superconformal index of 2d (2, 2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes the 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and under CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in = 2 super-conformal gauge theories. They are engineered by coupling the 2d (2, 2) supersymmetric gauge theory living on the support of the surface operator to the 4d = 2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools developed in the first half of the paper. The superconformal index in the presence of surface defect is expected to be invariant under generalized S-duality. We demonstrate that it is indeed the case. In doing so the Seiberg-type duality of the 2d theory plays an important role.
Trovato, Maria Antonietta; Palmara, Vittorio Italo; Rapisarda, Agnese Maria Chiara; Sturlese, Emanuele; De Dominici, Rosanna; Alecci, Stefano; D'Amico, Paolo; Triolo, Onofrio
2016-01-01
Endometriosis is defined as the presence of endometrial mucosa (glands and stroma) abnormally implanted in locations other than the uterine cavity. Deep infiltrating endometriosis (DIE) is considered the most aggressive presentation of the disease, penetrating more than 5 mm in affected tissues, and it is reported in approximately 20% of all women with endometriosis. DIE can cause a complete distortion of the pelvic anatomy and it mainly involves uterosacral ligaments, bladder, rectovaginal septum, rectum, and rectosigmoid colon. This review describes the state of the art in laparoscopic approach for DIE with a special interest in intestinal involvement, according to recent literature findings. Our attention has been focused particularly on full-thickness excision versus shaving technique in deep endometriosis intestinal involvement. Particularly, the aim of this paper is clarifying from the clinical and methodological points of view the best surgical treatment of deep intestinal endometriosis, since there is no standard of care in the literature and in different surgical settings. Indeed, this review tries to suggest when it is advisable to manage the full-thickness excision or the shaving technique, also analyzing perioperative management, main complications, and surgical outcomes. PMID:27579309
Laganà, Antonio Simone; Vitale, Salvatore Giovanni; Trovato, Maria Antonietta; Palmara, Vittorio Italo; Rapisarda, Agnese Maria Chiara; Granese, Roberta; Sturlese, Emanuele; De Dominici, Rosanna; Alecci, Stefano; Padula, Francesco; Chiofalo, Benito; Grasso, Roberta; Cignini, Pietro; D'Amico, Paolo; Triolo, Onofrio
2016-01-01
Endometriosis is defined as the presence of endometrial mucosa (glands and stroma) abnormally implanted in locations other than the uterine cavity. Deep infiltrating endometriosis (DIE) is considered the most aggressive presentation of the disease, penetrating more than 5 mm in affected tissues, and it is reported in approximately 20% of all women with endometriosis. DIE can cause a complete distortion of the pelvic anatomy and it mainly involves uterosacral ligaments, bladder, rectovaginal septum, rectum, and rectosigmoid colon. This review describes the state of the art in laparoscopic approach for DIE with a special interest in intestinal involvement, according to recent literature findings. Our attention has been focused particularly on full-thickness excision versus shaving technique in deep endometriosis intestinal involvement. Particularly, the aim of this paper is clarifying from the clinical and methodological points of view the best surgical treatment of deep intestinal endometriosis, since there is no standard of care in the literature and in different surgical settings. Indeed, this review tries to suggest when it is advisable to manage the full-thickness excision or the shaving technique, also analyzing perioperative management, main complications, and surgical outcomes. PMID:27579309
Yang, Dong; Jiang, Mei; Jin, Min; Qiu, Zhigang; Cui, Weihong; Shen, Zhiqiang; Li, Bo; Gong, Lianfeng; Chen, Zhaoli; Wang, Xinwei; Li, Jun-Wen
2013-12-01
The complete genome sequence of a genotype 4 strain of hepatitis E virus (CH-YT-HEV02) from a patient (in Yantai, China) has been determined. Phylogenetic analysis showed that CH-YT-HEV02 belongs to genotype 4, subtype 4a. However, the phylogenetic analysis indicated that it was most closely related to JKO-CHiSai98C (AB197673) strain, sharing only 91.6% sequence identity with it. Judging from the phylogenetic tree based on the full-length nucleotide sequences of all 70 genotype 4 HEV isolates retrieved from GenBank up to May, 2013, the CH-YT-HEV02 isolates could serve as a Yantai-indigenous strain. A broader comparison with other genotype isolates revealed that there are a few conserved amino acids in the HVR region of different HEV genotypes, and two amino acid motifs in ORF2 and ORF3 might serve as signatures of genotype diversity of HEV.
Ab initio modeling of 2D layered organohalide lead perovskites.
Fraccarollo, Alberto; Cantatore, Valentina; Boschetto, Gabriele; Marchese, Leonardo; Cossi, Maurizio
2016-04-28
A number of 2D layered perovskites A2PbI4 and BPbI4, with A and B mono- and divalent ammonium and imidazolium cations, have been modeled with different theoretical methods. The periodic structures have been optimized (both in monoclinic and in triclinic systems, corresponding to eclipsed and staggered arrangements of the inorganic layers) at the DFT level, with hybrid functionals, Gaussian-type orbitals and dispersion energy corrections. With the same methods, the various contributions to the solid stabilization energy have been discussed, separating electrostatic and dispersion energies, organic-organic intralayer interactions and H-bonding effects, when applicable. Then the electronic band gaps have been computed with plane waves, at the DFT level with scalar and full relativistic potentials, and including the correlation energy through the GW approximation. Spin orbit coupling and GW effects have been combined in an additive scheme, validated by comparing the computed gap with well known experimental and theoretical results for a model system. Finally, various contributions to the computed band gaps have been discussed on some of the studied systems, by varying some geometrical parameters and by substituting one cation in another's place. PMID:27131557
Rowley-Neale, Samuel J; Fearn, Jamie M; Brownson, Dale A C; Smith, Graham C; Ji, Xiaobo; Banks, Craig E
2016-08-21
Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm(-2) modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR. PMID:27448174
Tønning, Erik; Polders, Daniel; Callaghan, Paul T; Engelsen, Søren B
2007-09-01
This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T(2)-D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T(2)-D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T(2)-D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D=3 x 10(-12) m(2) s(-1) and T(2)=180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D=10(-9) m(2) s(-1), T(2)=10 ms and D=3 x 10(-13) m(2) s(-1), T(2)=13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it
Rowley-Neale, Samuel J; Fearn, Jamie M; Brownson, Dale A C; Smith, Graham C; Ji, Xiaobo; Banks, Craig E
2016-08-21
Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm(-2) modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.
NASA Astrophysics Data System (ADS)
Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.
2007-09-01
This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it
2D microwave imaging reflectometer electronics
Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.
2014-11-15
A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.
Inkjet printing of 2D layered materials.
Li, Jiantong; Lemme, Max C; Östling, Mikael
2014-11-10
Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials. PMID:25169938
Inkjet printing of 2D layered materials.
Li, Jiantong; Lemme, Max C; Östling, Mikael
2014-11-10
Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials.
Half-metallicity in 2D organometallic honeycomb frameworks
NASA Astrophysics Data System (ADS)
Sun, Hao; Li, Bin; Zhao, Jin
2016-10-01
Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule—CN—noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology.
Half-metallicity in 2D organometallic honeycomb frameworks.
Sun, Hao; Li, Bin; Zhao, Jin
2016-10-26
Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule-CN-noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology.
Half-metallicity in 2D organometallic honeycomb frameworks.
Sun, Hao; Li, Bin; Zhao, Jin
2016-10-26
Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule-CN-noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology. PMID:27541575
2D FEM Heat Transfer & E&M Field Code
1992-04-02
TOPAZ and TOPAZ2D are two-dimensional implicit finite element computer codes for heat transfer analysis. TOPAZ2D can also be used to solve electrostatic and magnetostatic problems. The programs solve for the steady-state or transient temperature or electrostatic and magnetostatic potential field on two-dimensional planar or axisymmetric geometries. Material properties may be temperature or potential-dependent and either isotropic or orthotropic. A variety of time and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. The programs can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.
2D FEM Heat Transfer & E&M Field Code
1992-04-02
TOPAZ and TOPAZ2D are two-dimensional implicit finite element computer codes for heat transfer analysis. TOPAZ2D can also be used to solve electrostatic and magnetostatic problems. The programs solve for the steady-state or transient temperature or electrostatic and magnetostatic potential field on two-dimensional planar or axisymmetric geometries. Material properties may be temperature or potential-dependent and either isotropic or orthotropic. A variety of time and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation.more » By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. The programs can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.« less
NASA High-Speed 2D Photogrammetric Measurement System
NASA Technical Reports Server (NTRS)
Dismond, Harriett R.
2012-01-01
The object of this report is to provide users of the NASA high-speed 2D photogrammetric measurement system with procedures required to obtain drop-model trajectory and impact data for full-scale and sub-scale models. This guide focuses on use of the system for vertical drop testing at the NASA Langley Landing and Impact Research (LandIR) Facility.
NASA Astrophysics Data System (ADS)
Rowley-Neale, Samuel J.; Fearn, Jamie M.; Brownson, Dale A. C.; Smith, Graham C.; Ji, Xiaobo; Banks, Craig E.
2016-08-01
Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.Two-dimensional molybdenum disulphide nanosheets
Stochastic Inversion of 2D Magnetotelluric Data
Chen, Jinsong
2010-07-01
The algorithm is developed to invert 2D magnetotelluric (MT) data based on sharp boundary parametrization using a Bayesian framework. Within the algorithm, we consider the locations and the resistivity of regions formed by the interfaces are as unknowns. We use a parallel, adaptive finite-element algorithm to forward simulate frequency-domain MT responses of 2D conductivity structure. Those unknown parameters are spatially correlated and are described by a geostatistical model. The joint posterior probability distribution function is explored by Markov Chain Monte Carlo (MCMC) sampling methods. The developed stochastic model is effective for estimating the interface locations and resistivity. Most importantly, it provides details uncertainty information on each unknown parameter. Hardware requirements: PC, Supercomputer, Multi-platform, Workstation; Software requirements C and Fortan; Operation Systems/version is Linux/Unix or Windows
Explicit 2-D Hydrodynamic FEM Program
1996-08-07
DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. Themore » isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.« less
Stochastic Inversion of 2D Magnetotelluric Data
2010-07-01
The algorithm is developed to invert 2D magnetotelluric (MT) data based on sharp boundary parametrization using a Bayesian framework. Within the algorithm, we consider the locations and the resistivity of regions formed by the interfaces are as unknowns. We use a parallel, adaptive finite-element algorithm to forward simulate frequency-domain MT responses of 2D conductivity structure. Those unknown parameters are spatially correlated and are described by a geostatistical model. The joint posterior probability distribution function ismore » explored by Markov Chain Monte Carlo (MCMC) sampling methods. The developed stochastic model is effective for estimating the interface locations and resistivity. Most importantly, it provides details uncertainty information on each unknown parameter. Hardware requirements: PC, Supercomputer, Multi-platform, Workstation; Software requirements C and Fortan; Operation Systems/version is Linux/Unix or Windows« less
Static & Dynamic Response of 2D Solids
1996-07-15
NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surfacemore » contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.« less
Static & Dynamic Response of 2D Solids
Lin, Jerry
1996-07-15
NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.
Explicit 2-D Hydrodynamic FEM Program
Lin, Jerry
1996-08-07
DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.
2D photonic-crystal optomechanical nanoresonator.
Makles, K; Antoni, T; Kuhn, A G; Deléglise, S; Briant, T; Cohadon, P-F; Braive, R; Beaudoin, G; Pinard, L; Michel, C; Dolique, V; Flaminio, R; Cagnoli, G; Robert-Philip, I; Heidmann, A
2015-01-15
We present the optical optimization of an optomechanical device based on a suspended InP membrane patterned with a 2D near-wavelength grating (NWG) based on a 2D photonic-crystal geometry. We first identify by numerical simulation a set of geometrical parameters providing a reflectivity higher than 99.8% over a 50-nm span. We then study the limitations induced by the finite value of the optical waist and lateral size of the NWG pattern using different numerical approaches. The NWG grating, pierced in a suspended InP 265-nm thick membrane, is used to form a compact microcavity involving the suspended nanomembrane as an end mirror. The resulting cavity has a waist size smaller than 10 μm and a finesse in the 200 range. It is used to probe the Brownian motion of the mechanical modes of the nanomembrane. PMID:25679837
Compact 2-D graphical representation of DNA
NASA Astrophysics Data System (ADS)
Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana
2003-05-01
We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.
2D materials: Graphene and others
NASA Astrophysics Data System (ADS)
Bansal, Suneev Anil; Singh, Amrinder Pal; Kumar, Suresh
2016-05-01
Present report reviews the recent advancements in new atomically thick 2D materials. Materials covered in this review are Graphene, Silicene, Germanene, Boron Nitride (BN) and Transition metal chalcogenides (TMC). These materials show extraordinary mechanical, electronic and optical properties which make them suitable candidates for future applications. Apart from unique properties, tune-ability of highly desirable properties of these materials is also an important area to be emphasized on.
Layer Engineering of 2D Semiconductor Junctions.
He, Yongmin; Sobhani, Ali; Lei, Sidong; Zhang, Zhuhua; Gong, Yongji; Jin, Zehua; Zhou, Wu; Yang, Yingchao; Zhang, Yuan; Wang, Xifan; Yakobson, Boris; Vajtai, Robert; Halas, Naomi J; Li, Bo; Xie, Erqing; Ajayan, Pulickel
2016-07-01
A new concept for junction fabrication by connecting multiple regions with varying layer thicknesses, based on the thickness dependence, is demonstrated. This type of junction is only possible in super-thin-layered 2D materials, and exhibits similar characteristics as p-n junctions. Rectification and photovoltaic effects are observed in chemically homogeneous MoSe2 junctions between domains of different thicknesses. PMID:27136275
2D Spinodal Decomposition in Forced Turbulence
NASA Astrophysics Data System (ADS)
Fan, Xiang; Diamond, Patrick; Chacon, Luis; Li, Hui
2015-11-01
Spinodal decomposition is a second order phase transition for binary fluid mixture, from one thermodynamic phase to form two coexisting phases. The governing equation for this coarsening process below critical temperature, Cahn-Hilliard Equation, is very similar to 2D MHD Equation, especially the conserved quantities have a close correspondence between each other, so theories for MHD turbulence are used to study spinodal decomposition in forced turbulence. Domain size is increased with time along with the inverse cascade, and the length scale can be arrested by a forced turbulence with direct cascade. The two competing mechanisms lead to a stabilized domain size length scale, which can be characterized by Hinze Scale. The 2D spinodal decomposition in forced turbulence is studied by both theory and simulation with ``pixie2d.'' This work focuses on the relation between Hinze scale and spectra and cascades. Similarities and differences between spinodal decomposition and MHD are investigated. Also some transport properties are studied following MHD theories. This work is supported by the Department of Energy under Award Number DE-FG02-04ER54738.
MAGNUM-2D computer code: user's guide
England, R.L.; Kline, N.W.; Ekblad, K.J.; Baca, R.G.
1985-01-01
Information relevant to the general use of the MAGNUM-2D computer code is presented. This computer code was developed for the purpose of modeling (i.e., simulating) the thermal and hydraulic conditions in the vicinity of a waste package emplaced in a deep geologic repository. The MAGNUM-2D computer computes (1) the temperature field surrounding the waste package as a function of the heat generation rate of the nuclear waste and thermal properties of the basalt and (2) the hydraulic head distribution and associated groundwater flow fields as a function of the temperature gradients and hydraulic properties of the basalt. MAGNUM-2D is a two-dimensional numerical model for transient or steady-state analysis of coupled heat transfer and groundwater flow in a fractured porous medium. The governing equations consist of a set of coupled, quasi-linear partial differential equations that are solved using a Galerkin finite-element technique. A Newton-Raphson algorithm is embedded in the Galerkin functional to formulate the problem in terms of the incremental changes in the dependent variables. Both triangular and quadrilateral finite elements are used to represent the continuum portions of the spatial domain. Line elements may be used to represent discrete conduits. 18 refs., 4 figs., 1 tab.
Engineering light outcoupling in 2D materials.
Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali
2015-02-11
When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.
A Better 2-D Mechanical Energy Conservation Experiment
NASA Astrophysics Data System (ADS)
Paesler, Michael
2012-02-01
A variety of simple classical mechanics energy conservation experiments are used in teaching laboratories. Typical one-dimensional (1-D) setups may involve falling balls or oscillating springs. Many of these can be quite satisfying in that students can confirm—within a few percent—that mechanical energy is conserved. Students generally have little trouble identifying discrepancies such as the loss of a few percent of the gravitational potential energy due to air friction encountered by a falling ball. Two-dimensional (2-D) systems can require more sophisticated analysis for higher level laboratories, but such systems often incorporate complicating components that can make the exercise academically incomplete and experimentally less accurate. The following describes a simple 2-D energy conservation experiment based on the popular "Newton's Cradle" toy that allows students to account for nearly all of the mechanical energy in the system in an academically complete analysis.
Targeting multiple types of tumors using NKG2D-coated iron oxide nanoparticles.
Wu, Ming-Ru; Cook, W James; Zhang, Tong; Sentman, Charles L
2014-11-28
Iron oxide nanoparticles (IONPs) hold great potential for cancer therapy. Actively targeting IONPs to tumor cells can further increase therapeutic efficacy and decrease off-target side effects. To target tumor cells, a natural killer (NK) cell activating receptor, NKG2D, was utilized to develop pan-tumor targeting IONPs. NKG2D ligands are expressed on many tumor types and its ligands are not found on most normal tissues under steady state conditions. The data showed that mouse and human fragment crystallizable (Fc)-fusion NKG2D (Fc-NKG2D) coated IONPs (NKG2D/NPs) can target multiple NKG2D ligand positive tumor types in vitro in a dose dependent manner by magnetic cell sorting. Tumor targeting effect was robust even under a very low tumor cell to normal cell ratio and targeting efficiency correlated with NKG2D ligand expression level on tumor cells. Furthermore, the magnetic separation platform utilized to test NKG2D/NP specificity has the potential to be developed into high throughput screening strategies to identify ideal fusion proteins or antibodies for targeting IONPs. In conclusion, NKG2D/NPs can be used to target multiple tumor types and magnetic separation platform can facilitate the proof-of-concept phase of tumor targeting IONP development.
Linkage studies for T2D in Chop and C/EBPbeta chromosomal regions in Italians.
Gragnoli, Claudia; Pierpaoli, Laura; Piumelli, Nunzia; Chiaramonte, Francesco
2007-11-01
The genes causing type 2 diabetes (T2D), a complex heterogeneous disorder, differ and/or overlap in various populations. Among others there are two loci in linkage to T2D, the chromosomes 20q12-13.1 and 12q15. These two regions harbor two genes, C/EBPbeta and CHOP, which are excellent candidate genes for T2D. In fact, C/EBPbeta protein cooperates with HNF4alpha (MODY1, monogenic form of diabetes) and 1alpha (MODY3, monogenic form of diabetes). C/EBPbeta mediates suppression of insulin gene transcription in hyperglycemia and may contribute to insulin-resistance. It interacts in a complex pathway with the CHOP protein. CHOP may play a role in altered beta-cell glucose metabolism, in beta-cell apoptosis, and in lack of beta-cell replication. Thus, both C/EBPbeta and CHOP genes may independently and interactively contribute to T2D. The chromosomal regions targeting C/EBPbeta and CHOP genes have never been previously explored in T2D. We planned to identify their potential contribution to T2D in Italians. We have genotyped a group of affected siblings/families with both late- and early-onset T2D around the C/EBPbeta and the CHOP genes. We have performed non-parametric linkage analysis in the total T2D group, in the late-onset and the early-onset group, separately. We have identified a suggestive linkage to T2D in the CHOP gene locus in the early-onset T2D group (P = 0.04). We identified the linkage to T2D in the chromosome 12q15 region in the early-onset T2D families and specifically target the CHOP gene. Our next step will be the identification of CHOP gene variants, which may contribute to the linkage to T2D in Italians. PMID:17620318
GBL-2D Version 1.0: a 2D geometry boolean library.
McBride, Cory L. (Elemental Technologies, American Fort, UT); Schmidt, Rodney Cannon; Yarberry, Victor R.; Meyers, Ray J.
2006-11-01
This report describes version 1.0 of GBL-2D, a geometric Boolean library for 2D objects. The library is written in C++ and consists of a set of classes and routines. The classes primarily represent geometric data and relationships. Classes are provided for 2D points, lines, arcs, edge uses, loops, surfaces and mask sets. The routines contain algorithms for geometric Boolean operations and utility functions. Routines are provided that incorporate the Boolean operations: Union(OR), XOR, Intersection and Difference. A variety of additional analytical geometry routines and routines for importing and exporting the data in various file formats are also provided. The GBL-2D library was originally developed as a geometric modeling engine for use with a separate software tool, called SummitView [1], that manipulates the 2D mask sets created by designers of Micro-Electro-Mechanical Systems (MEMS). However, many other practical applications for this type of software can be envisioned because the need to perform 2D Boolean operations can arise in many contexts.
NASA Technical Reports Server (NTRS)
Johnson, F. T.; Samant, S. S.; Bieterman, M. B.; Melvin, R. G.; Young, D. P.; Bussoletti, J. E.; Hilmes, C. L.
1992-01-01
The TranAir computer program calculates transonic flow about arbitrary configurations at subsonic, transonic, and supersonic freestream Mach numbers. TranAir solves the nonlinear full potential equations subject to a variety of boundary conditions modeling wakes, inlets, exhausts, porous walls, and impermeable surfaces. Regions with different total temperature and pressure can be represented. The user's manual describes how to run the TranAir program and its graphical support programs.
Periodically sheared 2D Yukawa systems
Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán
2015-10-15
We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.
ENERGY LANDSCAPE OF 2D FLUID FORMS
Y. JIANG; ET AL
2000-04-01
The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.
Conformal Laplace superintegrable systems in 2D: polynomial invariant subspaces
NASA Astrophysics Data System (ADS)
Escobar-Ruiz, M. A.; Miller, Willard, Jr.
2016-07-01
2nd-order conformal superintegrable systems in n dimensions are Laplace equations on a manifold with an added scalar potential and 2n-1 independent 2nd order conformal symmetry operators. They encode all the information about Helmholtz (eigenvalue) superintegrable systems in an efficient manner: there is a 1-1 correspondence between Laplace superintegrable systems and Stäckel equivalence classes of Helmholtz superintegrable systems. In this paper we focus on superintegrable systems in two-dimensions, n = 2, where there are 44 Helmholtz systems, corresponding to 12 Laplace systems. For each Laplace equation we determine the possible two-variate polynomial subspaces that are invariant under the action of the Laplace operator, thus leading to families of polynomial eigenfunctions. We also study the behavior of the polynomial invariant subspaces under a Stäckel transform. The principal new results are the details of the polynomial variables and the conditions on parameters of the potential corresponding to polynomial solutions. The hidden gl 3-algebraic structure is exhibited for the exact and quasi-exact systems. For physically meaningful solutions, the orthogonality properties and normalizability of the polynomials are presented as well. Finally, for all Helmholtz superintegrable solvable systems we give a unified construction of one-dimensional (1D) and two-dimensional (2D) quasi-exactly solvable potentials possessing polynomial solutions, and a construction of new 2D PT-symmetric potentials is established.
Report of the 1988 2-D Intercomparison Workshop, chapter 3
NASA Technical Reports Server (NTRS)
Jackman, Charles H.; Brasseur, Guy; Soloman, Susan; Guthrie, Paul D.; Garcia, Rolando; Yung, Yuk L.; Gray, Lesley J.; Tung, K. K.; Ko, Malcolm K. W.; Isaken, Ivar
1989-01-01
Several factors contribute to the errors encountered. With the exception of the line-by-line model, all of the models employ simplifying assumptions that place fundamental limits on their accuracy and range of validity. For example, all 2-D modeling groups use the diffusivity factor approximation. This approximation produces little error in tropospheric H2O and CO2 cooling rates, but can produce significant errors in CO2 and O3 cooling rates at the stratopause. All models suffer from fundamental uncertainties in shapes and strengths of spectral lines. Thermal flux algorithms being used in 2-D tracer tranport models produce cooling rates that differ by as much as 40 percent for the same input model atmosphere. Disagreements of this magnitude are important since the thermal cooling rates must be subtracted from the almost-equal solar heating rates to derive the net radiative heating rates and the 2-D model diabatic circulation. For much of the annual cycle, the net radiative heating rates are comparable in magnitude to the cooling rate differences described. Many of the models underestimate the cooling rates in the middle and lower stratosphere. The consequences of these errors for the net heating rates and the diabatic circulation will depend on their meridional structure, which was not tested here. Other models underestimate the cooling near 1 mbar. Suchs errors pose potential problems for future interactive ozone assessment studies, since they could produce artificially-high temperatures and increased O3 destruction at these levels. These concerns suggest that a great deal of work is needed to improve the performance of thermal cooling rate algorithms used in the 2-D tracer transport models.
Microwave Assisted 2D Materials Exfoliation
NASA Astrophysics Data System (ADS)
Wang, Yanbin
Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.
Multienzyme Inkjet Printed 2D Arrays.
Gdor, Efrat; Shemesh, Shay; Magdassi, Shlomo; Mandler, Daniel
2015-08-19
The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solutions as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochemical microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM. PMID:26214072
2-D or not 2-D, that is the question: A Northern California test
Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D
2005-06-06
Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is still preferable over 2
A Comparison of 2D to 3D Hydro Simulations of Asteroid Mitigation by a Strong Surface Explosion
NASA Astrophysics Data System (ADS)
Weaver, R.; Dearholdt, W.
2011-12-01
Disruption of a potentially hazardous object (PHO) by an energetic surface or subsurface burst is considered as one possible method of impact-hazard mitigation. This technique of employing surface or subsurface explosions has been popularized in the media but is probably one of the lower priority deflection/disruption methods, unless the warning time is short. In all of our current simulation we use realistic RADAR shape models for the initial geometry, not merely spherical objects. The non-sphericity of the geometry is very important in the resultant shock hydrodynamic evolution. This work is a follow-on to previous 2D simulations with the RAGE hydrocode to simulate the imparted momentum as a function of depth-of-burial (DOB) on a non-spherical "rubble pile" composition. Specifically, here, we have started a full 3D simulation of a 1 Mt surface explosion on a porous (~40% porosity) "rubble pile" model in the shape of asteroid 25143 Itokawa. This simulation has progressed far enough to start comparisons between the 2D and 3D runs of this model. There are significant changes in the 3D geometry that reduce the momentum imparted to the asteroid in these RAGE simulations. I will discuss this set of simulations, give some background results from previous 2D simulations and indicate the differences between 2D and 3D simulations.
Transport Experiments on 2D Correlated Electron Physics in Semiconductors
Tsui, Daniel
2014-03-24
This research project was designed to investigate experimentally the transport properties of the 2D electrons in Si and GaAs, two prototype semiconductors, in several new physical regimes that were previously inaccessible to experiments. The research focused on the strongly correlated electron physics in the dilute density limit, where the electron potential energy to kinetic energy ratio rs>>1, and on the fractional quantum Hall effect related physics in nuclear demagnetization refrigerator temperature range on samples with new levels of purity and controlled random disorder.
Repression of multiple CYP2D genes in mouse primary hepatocytes with a single siRNA construct.
Elraghy, Omaima; Baldwin, William S
2015-01-01
The Cyp2d subfamily is the second most abun-dant subfamily of hepatic drug-metabolizing CYPs. In mice, there are nine Cyp2d members that are believed to have redundant catalytic activity. We are testing and optimizing the ability of one short interfering RNA (siRNA) construct to knockdown the expression of multiple mouse Cyp2ds in primary hepatocytes. Expression of Cyp2d10, Cyp2d11, Cyp2d22, and Cyp2d26 was observed in the primary male mouse hepatocytes. Cyp2d9, which is male-specific and growth hormone-dependent, was not expressed in male primary hepatocytes, potentially because of its dependence on pulsatile growth hormone release from the anterior pituitary. Several different siRNAs at different concentrations and with different reagents were used to knockdown Cyp2d expression. siRNA constructs designed to repress only one construct often mildly repressed several Cyp2d isoforms. A construct designed to knockdown every Cyp2d isoform provided the best results, especially when incubated with transfection reagents designed specifically for primary cell culture. Interestingly, a construct designed to knockdown all Cyp2d isoforms, except Cyp2d10, caused a 2.5× increase in Cyp2d10 expression, presumably because of a compensatory response. However, while RNA expression is repressed 24 h after siRNA treatment, associated changes in Cyp2d-mediated metabolism are tenuous. Overall, this study provides data on the expression of murine Cyp2ds in primary cell lines, valuable information on designing siRNAs for silencing multiple murine CYPs, and potential pros and cons of using siRNA as a tool for repressing Cyp2d and estimating Cyp2d's role in murine xenobiotic metabolism. PMID:25124873
2D Electrostatic Actuation of Microshutter Arrays
NASA Technical Reports Server (NTRS)
Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Kelly, Daniel P.; Kutyrev, Alexander S.; Moseley, Samuel H.
2015-01-01
Electrostatically actuated microshutter arrays consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutters demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.
2D Electrostatic Actuation of Microshutter Arrays
NASA Technical Reports Server (NTRS)
Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.
2015-01-01
An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.
2D quantum gravity from quantum entanglement.
Gliozzi, F
2011-01-21
In quantum systems with many degrees of freedom the replica method is a useful tool to study the entanglement of arbitrary spatial regions. We apply it in a way that allows them to backreact. As a consequence, they become dynamical subsystems whose position, form, and extension are determined by their interaction with the whole system. We analyze, in particular, quantum spin chains described at criticality by a conformal field theory. Its coupling to the Gibbs' ensemble of all possible subsystems is relevant and drives the system into a new fixed point which is argued to be that of the 2D quantum gravity coupled to this system. Numerical experiments on the critical Ising model show that the new critical exponents agree with those predicted by the formula of Knizhnik, Polyakov, and Zamolodchikov.
Graphene suspensions for 2D printing
NASA Astrophysics Data System (ADS)
Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.
2016-04-01
It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).
Metrology for graphene and 2D materials
NASA Astrophysics Data System (ADS)
Pollard, Andrew J.
2016-09-01
The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the
Simulation of 2D Fields of Raindrop Size Distributions
NASA Astrophysics Data System (ADS)
Berne, A.; Schleiss, M.; Uijlenhoet, R.
2008-12-01
The raindrop size distribution (DSD hereafter) is of primary importance for quantitative applications of weather radar measurements. The radar reflectivity~Z (directly measured by radar) is related to the power backscattered by the ensemble of hydrometeors within the radar sampling volume. However, the rain rate~R (the flux of water to the surface) is the variable of interest for many applications (hydrology, weather forecasting, air traffic for example). Usually, radar reflectivity is converted into rain rate using a power law such as Z=aRb. The coefficients a and b of the Z-R relationship depend on the DSD. The variability of the DSD in space and time has to be taken into account to improve radar rain rate estimates. Therefore, the ability to generate a large number of 2D fields of DSD which are statistically homogeneous provides a very useful simulation framework that nicely complements experimental approaches based on DSD data, in order to investigate radar beam propagation through rain as well as radar retrieval techniques. The proposed approach is based on geostatistics for structural analysis and stochastic simulation. First, the DSD is assumed to follow a gamma distribution. Hence a 2D field of DSDs can be adequately described as a 2D field of a multivariate random function consisting of the three DSD parameters. Such fields are simulated by combining a Gaussian anamorphosis and a multivariate Gaussian random field simulation algorithm. Using the (cross-)variogram models fitted on data guaranties that the spatial structure of the simulated fields is consistent with the observed one. To assess its validity, the proposed method is applied to data collected during intense Mediterranean rainfall. As only time series are available, Taylor's hypothesis is assumed to convert time series in 1D range profile. Moreover, DSD fields are assumed to be isotropic so that the 1D structure can be used to simulate 2D fields. A large number of 2D fields of DSD parameters are
Gaedigk, Andrea; Bradford, L Dianne; Alander, Sarah W; Leeder, J Steven
2006-04-01
Unexplained cases of CYP2D6 genotype/phenotype discordance continue to be discovered. In previous studies, several African Americans with a poor metabolizer phenotype carried the reduced function CYP2D6*10 allele in combination with a nonfunctional allele. We pursued the possibility that these alleles harbor either a known sequence variation (i.e., CYP2D6*36 carrying a gene conversion in exon 9 along the CYP2D6*10-defining 100C>T single-nucleotide polymorphism) or novel sequences variation(s). Discordant cases were evaluated by long-range polymerase chain reaction (PCR) to test for gene rearrangement events, and a 6.6-kilobase pair PCR product encompassing the CYP2D6 gene was cloned and entirely sequenced. Thereafter, allele frequencies were determined in different study populations comprising whites, African Americans, and Asians. Analyses covering the CYP2D7 to 2D6 gene region established that CYP2D6*36 did not only exist as a gene duplication (CYP2D6*36x2) or in tandem with *10 (CYP2D6*36+*10), as previously reported, but also by itself. This "single" CYP2D6*36 allele was found in nine African Americans and one Asian, but was absent in the whites tested. Ultimately, the presence of CYP2D6*36 resolved genotype/phenotype discordance in three cases. We also discovered an exon 9 conversion-positive CYP2D6*4 gene in a duplication arrangement (CYP2D6*4Nx2) and a CYP2D6*4 allele lacking 100C>T (CYP2D6*4M) in two white subjects. The discovery of an allele that carries only one CYP2D6*36 gene copy provides unequivocal evidence that both CYP2D6*36 and *36x2 are associated with a poor metabolizer phenotype. Given a combined frequency of between 0.5 and 3% in African Americans and Asians, genotyping for CYP2D6*36 should improve the accuracy of genotype-based phenotype prediction in these populations.
NASA Astrophysics Data System (ADS)
Lacava, C.; Carrol, L.; Bozzola, A.; Marchetti, R.; Minzioni, P.; Cristiani, I.; Fournier, M.; Bernabe, S.; Gerace, D.; Andreani, L. C.
2016-03-01
We present the characterization of Silicon-on-insulator (SOI) photonic-crystal based 2D grating-couplers (2D-GCs) fabricated by CEA-Leti in the frame of the FP7 Fabulous project, which is dedicated to the realization of devices and systems for low-cost and high-performance passives-optical-networks. On the analyzed samples different test structures are present, including 2D-GC connected to another 2D-GC by different waveguides (in a Mach-Zehnder like configuration), and 2D-GC connected to two separate 2D-GCs, so as to allow a complete assessment of different parameters. Measurements were carried out using a tunable laser source operating in the extended telecom bandwidth and a fiber-based polarization controlling system at the input of device-under-test. The measured data yielded an overall fiber-to-fiber loss of 7.5 dB for the structure composed by an input 2D-GC connected to two identical 2D-GCs. This value was obtained at the peak wavelength of the grating, and the 3-dB bandwidth of the 2D-GC was assessed to be 43 nm. Assuming that the waveguide losses are negligible, so as to make a worst-case analysis, the coupling efficiency of the single 2D-GC results to be equal to -3.75 dB, constituting, to the best of our knowledge, the lowest value ever reported for a fully CMOS compatible 2D-GC. It is worth noting that both the obtained values are in good agreement with those expected by the numerical simulations performed using full 3D analysis by Lumerical FDTD-solutions.
A new inversion method for (T2, D) 2D NMR logging and fluid typing
NASA Astrophysics Data System (ADS)
Tan, Maojin; Zou, Youlong; Zhou, Cancan
2013-02-01
One-dimensional nuclear magnetic resonance (1D NMR) logging technology has some significant limitations in fluid typing. However, not only can two-dimensional nuclear magnetic resonance (2D NMR) provide some accurate porosity parameters, but it can also identify fluids more accurately than 1D NMR. In this paper, based on the relaxation mechanism of (T2, D) 2D NMR in a gradient magnetic field, a hybrid inversion method that combines least-squares-based QR decomposition (LSQR) and truncated singular value decomposition (TSVD) is examined in the 2D NMR inversion of various fluid models. The forward modeling and inversion tests are performed in detail with different acquisition parameters, such as magnetic field gradients (G) and echo spacing (TE) groups. The simulated results are discussed and described in detail, the influence of the above-mentioned observation parameters on the inversion accuracy is investigated and analyzed, and the observation parameters in multi-TE activation are optimized. Furthermore, the hybrid inversion can be applied to quantitatively determine the fluid saturation. To study the effects of noise level on the hybrid method and inversion results, the numerical simulation experiments are performed using different signal-to-noise-ratios (SNRs), and the effect of different SNRs on fluid typing using three fluid models are discussed and analyzed in detail.
Application Perspective of 2D+SCALE Dimension
NASA Astrophysics Data System (ADS)
Karim, H.; Rahman, A. Abdul
2016-09-01
Different applications or users need different abstraction of spatial models, dimensionalities and specification of their datasets due to variations of required analysis and output. Various approaches, data models and data structures are now available to support most current application models in Geographic Information System (GIS). One of the focuses trend in GIS multi-dimensional research community is the implementation of scale dimension with spatial datasets to suit various scale application needs. In this paper, 2D spatial datasets that been scaled up as the third dimension are addressed as 2D+scale (or 3D-scale) dimension. Nowadays, various data structures, data models, approaches, schemas, and formats have been proposed as the best approaches to support variety of applications and dimensionality in 3D topology. However, only a few of them considers the element of scale as their targeted dimension. As the scale dimension is concerned, the implementation approach can be either multi-scale or vario-scale (with any available data structures and formats) depending on application requirements (topology, semantic and function). This paper attempts to discuss on the current and new potential applications which positively could be integrated upon 3D-scale dimension approach. The previous and current works on scale dimension as well as the requirements to be preserved for any given applications, implementation issues and future potential applications forms the major discussion of this paper.
Wang, Yimin; Braams, Bastiaan J; Bowman, Joel M; Carter, Stuart; Tew, David P
2008-06-14
Quantum calculations of the ground vibrational state tunneling splitting of H-atom and D-atom transfer in malonaldehyde are performed on a full-dimensional ab initio potential energy surface (PES). The PES is a fit to 11 147 near basis-set-limit frozen-core CCSD(T) electronic energies. This surface properly describes the invariance of the potential with respect to all permutations of identical atoms. The saddle-point barrier for the H-atom transfer on the PES is 4.1 kcalmol, in excellent agreement with the reported ab initio value. Model one-dimensional and "exact" full-dimensional calculations of the splitting for H- and D-atom transfer are done using this PES. The tunneling splittings in full dimensionality are calculated using the unbiased "fixed-node" diffusion Monte Carlo (DMC) method in Cartesian and saddle-point normal coordinates. The ground-state tunneling splitting is found to be 21.6 cm(-1) in Cartesian coordinates and 22.6 cm(-1) in normal coordinates, with an uncertainty of 2-3 cm(-1). This splitting is also calculated based on a model which makes use of the exact single-well zero-point energy (ZPE) obtained with the MULTIMODE code and DMC ZPE and this calculation gives a tunneling splitting of 21-22 cm(-1). The corresponding computed splittings for the D-atom transfer are 3.0, 3.1, and 2-3 cm(-1). These calculated tunneling splittings agree with each other to within less than the standard uncertainties obtained with the DMC method used, which are between 2 and 3 cm(-1), and agree well with the experimental values of 21.6 and 2.9 cm(-1) for the H and D transfer, respectively.
Competing coexisting phases in 2D water
Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire
2016-01-01
The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018
Phase Engineering of 2D Tin Sulfides.
Mutlu, Zafer; Wu, Ryan J; Wickramaratne, Darshana; Shahrezaei, Sina; Liu, Chueh; Temiz, Selcuk; Patalano, Andrew; Ozkan, Mihrimah; Lake, Roger K; Mkhoyan, K A; Ozkan, Cengiz S
2016-06-01
Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2 and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO2 substrates through atmospheric pressure vapor-phase method in a conventional horizontal quartz tube furnace with SnO2 and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations. PMID:27099950
Phase Engineering of 2D Tin Sulfides.
Mutlu, Zafer; Wu, Ryan J; Wickramaratne, Darshana; Shahrezaei, Sina; Liu, Chueh; Temiz, Selcuk; Patalano, Andrew; Ozkan, Mihrimah; Lake, Roger K; Mkhoyan, K A; Ozkan, Cengiz S
2016-06-01
Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2 and orthorhombic tin (II) sulfide SnS crystals with diameters of over tens of microns on SiO2 substrates through atmospheric pressure vapor-phase method in a conventional horizontal quartz tube furnace with SnO2 and S powders as the source materials. Detailed characterization of each phase of tin sulfide crystals is performed using various microscopy and spectroscopy methods, and the results are corroborated by ab initio density functional theory calculations.
Competing coexisting phases in 2D water
NASA Astrophysics Data System (ADS)
Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire
2016-05-01
The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.
2-D Modeling of Nanoscale MOSFETs: Non-Equilibrium Green's Function Approach
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, Bryan
2001-01-01
We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions and oxide tunneling are treated on an equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. Electron-electron interaction is treated within Hartree approximation by solving NEGF and Poisson equations self-consistently. For the calculations presented here, parallelization is performed by distributing the solution of NEGF equations to various processors, energy wise. We present simulation of the "benchmark" MIT 25nm and 90nm MOSFETs and compare our results to those from the drift-diffusion simulator and the quantum-corrected results available. In the 25nm MOSFET, the channel length is less than ten times the electron wavelength, and the electron scattering time is comparable to its transit time. Our main results are: (1) Simulated drain subthreshold current characteristics are shown, where the potential profiles are calculated self-consistently by the corresponding simulation methods. The current predicted by our quantum simulation has smaller subthreshold slope of the Vg dependence which results in higher threshold voltage. (2) When gate oxide thickness is less than 2 nm, gate oxide leakage is a primary factor which determines off-current of a MOSFET (3) Using our 2-D NEGF simulator, we found several ways to drastically decrease oxide leakage current without compromising drive current. (4) Quantum mechanically calculated electron density is much smaller than the background doping density in the poly silicon gate region near oxide interface. This creates an additional effective gate voltage. Different ways to. include this effect approximately will be discussed.
Fast acceleration of 2D wave propagation simulations using modern computational accelerators.
Wang, Wei; Xu, Lifan; Cavazos, John; Huang, Howie H; Kay, Matthew
2014-01-01
Recent developments in modern computational accelerators like Graphics Processing Units (GPUs) and coprocessors provide great opportunities for making scientific applications run faster than ever before. However, efficient parallelization of scientific code using new programming tools like CUDA requires a high level of expertise that is not available to many scientists. This, plus the fact that parallelized code is usually not portable to different architectures, creates major challenges for exploiting the full capabilities of modern computational accelerators. In this work, we sought to overcome these challenges by studying how to achieve both automated parallelization using OpenACC and enhanced portability using OpenCL. We applied our parallelization schemes using GPUs as well as Intel Many Integrated Core (MIC) coprocessor to reduce the run time of wave propagation simulations. We used a well-established 2D cardiac action potential model as a specific case-study. To the best of our knowledge, we are the first to study auto-parallelization of 2D cardiac wave propagation simulations using OpenACC. Our results identify several approaches that provide substantial speedups. The OpenACC-generated GPU code achieved more than 150x speedup above the sequential implementation and required the addition of only a few OpenACC pragmas to the code. An OpenCL implementation provided speedups on GPUs of at least 200x faster than the sequential implementation and 30x faster than a parallelized OpenMP implementation. An implementation of OpenMP on Intel MIC coprocessor provided speedups of 120x with only a few code changes to the sequential implementation. We highlight that OpenACC provides an automatic, efficient, and portable approach to achieve parallelization of 2D cardiac wave simulations on GPUs. Our approach of using OpenACC, OpenCL, and OpenMP to parallelize this particular model on modern computational accelerators should be applicable to other computational models of
2-D Animation's Not Just for Mickey Mouse.
ERIC Educational Resources Information Center
Weinman, Lynda
1995-01-01
Discusses characteristics of two-dimensional (2-D) animation; highlights include character animation, painting issues, and motion graphics. Sidebars present Silicon Graphics animations tools and 2-D animation programs for the desktop computer. (DGM)
Crossover from 2D to 3D in a Weakly Interacting Fermi Gas
Dyke, P.; Kuhnle, E. D.; Hu, H.; Mark, M.; Hoinka, S.; Lingham, M.; Hannaford, P.; Vale, C. J.; Whitlock, S.
2011-03-11
We have studied the transition from two to three dimensions in a low temperature weakly interacting {sup 6}Li Fermi gas. Below a critical atom number N{sub 2D} only the lowest transverse vibrational state of a highly anisotropic oblate trapping potential is occupied and the gas is two dimensional. Above N{sub 2D} the Fermi gas enters the quasi-2D regime where shell structure associated with the filling of individual transverse oscillator states is apparent. This dimensional crossover is demonstrated through measurements of the cloud size and aspect ratio versus atom number.
Generates 2D Input for DYNA NIKE & TOPAZ
Hallquist, J. O.; Sanford, Larry
1996-07-15
MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
MAZE96. Generates 2D Input for DYNA NIKE & TOPAZ
Sanford, L.; Hallquist, J.O.
1992-02-24
MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
NASA Astrophysics Data System (ADS)
Otto, Frank; Gatti, Fabien; Meyer, Hans-Dieter
2008-02-01
We study the process of rotational excitation in the collisions of para-H2 with para-H2 by propagating wave packets with the multiconfiguration time-dependent Hartree (MCTDH) algorithm. Transition probabilities are then calculated by the method of Tannor and Weeks based on time-correlation functions. Calculations were carried out up to a total angular momentum of J =70 to compute integral cross sections up to 1.2eV in collision energy and thermal rate coefficients from 100to3000K. The process is studied on the full-dimensional potential energy surface of Boothroyd-Martin-Keogh-Peterson (BMKP) as well as on the rigid rotor surface of Diep and Johnson. We test the validity of the rigid rotor approximation by also considering two rigid rotor restrictions of the BMKP potential energy surface (PES). Additionally, we investigate a variant of the BMKP PES suggested by Pogrebnya and Clary [Chem. Phys. Lett. 363, 523 (2002)] with reduced anisotropy. We compare our results with previous theoretical data for the cross sections and with experimental data for the rate coefficients at low temperatures.
Song, Hongwei; Lu, Yunpeng; Li, Jun; Yang, Minghui; Guo, Hua
2016-04-28
An initial state selected time-dependent wave packet method is applied to study the dynamics of the OH + CHD3 reaction with a six-dimensional model on a newly developed full-dimensional ab initio potential energy surface (PES). This quantum dynamical (QD) study is complemented by full-dimensional quasi-classical trajectory (QCT) calculations on the same PES. The QD results indicate that both translational energy and the excitation of the CH stretching mode significantly promote the reaction while the excitation of the umbrella mode has a negligible effect on the reactivity. For this early barrier reaction, interestingly, the CH stretching mode is more effective than translational energy in promoting the reaction except at very low collision energies. These QD observations are supported by QCT results. The higher efficacy of the CH stretching model in promoting this early barrier reaction is inconsistent with the prediction of the naively extended Polanyi's rules, but can be rationalized by the recently proposed sudden vector projection model.
2d PDE Linear Symmetric Matrix Solver
1983-10-01
ICCG2 (Incomplete Cholesky factorized Conjugate Gradient algorithm for 2d symmetric problems) was developed to solve a linear symmetric matrix system arising from a 9-point discretization of two-dimensional elliptic and parabolic partial differential equations found in plasma physics applications, such as resistive MHD, spatial diffusive transport, and phase space transport (Fokker-Planck equation) problems. These problems share the common feature of being stiff and requiring implicit solution techniques. When these parabolic or elliptic PDE''s are discretized withmore » finite-difference or finite-element methods,the resulting matrix system is frequently of block-tridiagonal form. To use ICCG2, the discretization of the two-dimensional partial differential equation and its boundary conditions must result in a block-tridiagonal supermatrix composed of elementary tridiagonal matrices. The incomplete Cholesky conjugate gradient algorithm is used to solve the linear symmetric matrix equation. Loops are arranged to vectorize on the Cray1 with the CFT compiler, wherever possible. Recursive loops, which cannot be vectorized, are written for optimum scalar speed. For matrices lacking symmetry, ILUCG2 should be used. Similar methods in three dimensions are available in ICCG3 and ILUCG3. A general source containing extensions and macros, which must be processed by a pre-compiler to obtain the standard FORTRAN source, is provided along with the standard FORTRAN source because it is believed to be more readable. The pre-compiler is not included, but pre-compilation may be performed by a text editor as described in the UCRL-88746 Preprint.« less
2d PDE Linear Asymmetric Matrix Solver
1983-10-01
ILUCG2 (Incomplete LU factorized Conjugate Gradient algorithm for 2d problems) was developed to solve a linear asymmetric matrix system arising from a 9-point discretization of two-dimensional elliptic and parabolic partial differential equations found in plasma physics applications, such as plasma diffusion, equilibria, and phase space transport (Fokker-Planck equation) problems. These equations share the common feature of being stiff and requiring implicit solution techniques. When these parabolic or elliptic PDE''s are discretized with finite-difference or finite-elementmore » methods, the resulting matrix system is frequently of block-tridiagonal form. To use ILUCG2, the discretization of the two-dimensional partial differential equation and its boundary conditions must result in a block-tridiagonal supermatrix composed of elementary tridiagonal matrices. A generalization of the incomplete Cholesky conjugate gradient algorithm is used to solve the matrix equation. Loops are arranged to vectorize on the Cray1 with the CFT compiler, wherever possible. Recursive loops, which cannot be vectorized, are written for optimum scalar speed. For problems having a symmetric matrix ICCG2 should be used since it runs up to four times faster and uses approximately 30% less storage. Similar methods in three dimensions are available in ICCG3 and ILUCG3. A general source, containing extensions and macros, which must be processed by a pre-compiler to obtain the standard FORTRAN source, is provided along with the standard FORTRAN source because it is believed to be more readable. The pre-compiler is not included, but pre-compilation may be performed by a text editor as described in the UCRL-88746 Preprint.« less
Position control using 2D-to-2D feature correspondences in vision guided cell micromanipulation.
Zhang, Yanliang; Han, Mingli; Shee, Cheng Yap; Ang, Wei Tech
2007-01-01
Conventional camera calibration that utilizes the extrinsic and intrinsic parameters of the camera and the objects has certain limitations for micro-level cell operations due to the presence of hardware deviations and external disturbances during the experimental process, thereby invalidating the extrinsic parameters. This invalidation is often neglected in macro-world visual servoing and affects the visual image processing quality, causing deviation from the desired position in micro-level cell operations. To increase the success rate of vision guided biological micromanipulations, a novel algorithm monitoring the changing image pattern of the manipulators including the injection micropipette and cell holder is designed and implemented based on 2 dimensional (2D)-to 2D feature correspondences and can adjust the manipulator and perform position control simultaneously. When any deviation is found, the manipulator is retracted to the initial focusing plane before continuing the operation.
NASA Astrophysics Data System (ADS)
Hou, Dan; Ma, Yong-Tao; Zhang, Xiao-Long; Li, Hui
2016-06-01
The origin and strength of intra- and inter-molecular vibrational coupling is difficult to probe by direct experimental observations. However, explicitly including or not including some specific intramolecular vibrational modes to study intermolecular interaction provides a precise theoretical way to examine the effects of anharmonic coupling between modes. In this work, a full-dimension intra- and inter-molecular ab initio potential energy surface (PES) for H_2O-Ar, which explicitly incorporates interdependence on the intramolecular normal-mode coordinates of the H_2O monomer, has been calculated. In addition, four analytic vibrational-quantum-state-specific PESs are obtained by least-squares fitting vibrationally averaged interaction energies for the (νb{1},νb{2},νb{3})=(0,0,0),(0,0,1),(1,0,0),(0,1,0) states of H_2O to the three-dimensional Morse/long-range potential function. The resulting vibrationally averaged PESs provide good representations of the experimental infrared data, with RMS discrepancies smaller than 0.02 wn for all three rotational branches of the asymmetric stretch fundamental transitions. The infrared band origin shifts associated with three fundamental bands of H_2O in H_2O-Ar complex are predicted for the first time and are found to be in good agreement with the (extrapolated) experimental values. Upon introduction of additional intramolecular degrees of freedom into the intermolecular potential energy surface, there is clear spectroscopic evidence of intra- and intermolecular vibrational couplings. J. Chem. Phys., 144, 014301 (2016)
Local currents in a 2D topological insulator.
Dang, Xiaoqian; Burton, J D; Tsymbal, Evgeny Y
2015-12-23
Symmetry protected edge states in 2D topological insulators are interesting both from the fundamental point of view as well as from the point of view of potential applications in nanoelectronics as perfectly conducting 1D channels and functional elements of circuits. Here using a simple tight-binding model and the Landauer-Büttiker formalism we explore local current distributions in a 2D topological insulator focusing on effects of non-magnetic impurities and vacancies as well as finite size effects. For an isolated edge state, we show that the local conductance decays into the bulk in an oscillatory fashion as explained by the complex band structure of the bulk topological insulator. We demonstrate that although the net conductance of the edge state is topologically protected, impurity scattering leads to intricate local current patterns. In the case of vacancies we observe vortex currents of certain chirality, originating from the scattering of current-carrying electrons into states localized at the edges of hollow regions. For finite size strips of a topological insulator we predict the formation of an oscillatory band gap in the spectrum of the edge states, the emergence of Friedel oscillations caused by an open channel for backscattering from an impurity and antiresonances in conductance when the Fermi energy matches the energy of the localized state created by an impurity. PMID:26610145
Predicting abnormal pressure from 2-D seismic velocity modeling
Grauls, D.; Dunand, J.P.; Beaufort, D.
1995-12-01
Seismic velocities are the only data available, before drilling, on which to base a quantitative, present-day estimate of abnormal pressure. Recent advances in seismic velocity processing have enabled them to obtain, using an in-house approach, an optimized 2-D interval velocity field and consequently to better define the lateral extension of pressure regimes. The methodology, interpretation and quantification of overpressure-related anomalies are supported by case studies, selected in sand-shale dominated Tertiary basins, offshore West Africa. Another advantage of this approach is that it can also account for the presence of reservoir-potential intervals at great depth and thus provide significant insight, from a prospective standpoint, into very poorly explored areas. Although at the outset the 2-D seismic tool legitimately merits being favored, optimization of the final predictive pressure model, prior to drilling, will depend upon the success of its combined use with other concepts and approaches, pertaining to structural geology, sedimentology, rock mechanics and fluid dynamics.
Local currents in a 2D topological insulator.
Dang, Xiaoqian; Burton, J D; Tsymbal, Evgeny Y
2015-12-23
Symmetry protected edge states in 2D topological insulators are interesting both from the fundamental point of view as well as from the point of view of potential applications in nanoelectronics as perfectly conducting 1D channels and functional elements of circuits. Here using a simple tight-binding model and the Landauer-Büttiker formalism we explore local current distributions in a 2D topological insulator focusing on effects of non-magnetic impurities and vacancies as well as finite size effects. For an isolated edge state, we show that the local conductance decays into the bulk in an oscillatory fashion as explained by the complex band structure of the bulk topological insulator. We demonstrate that although the net conductance of the edge state is topologically protected, impurity scattering leads to intricate local current patterns. In the case of vacancies we observe vortex currents of certain chirality, originating from the scattering of current-carrying electrons into states localized at the edges of hollow regions. For finite size strips of a topological insulator we predict the formation of an oscillatory band gap in the spectrum of the edge states, the emergence of Friedel oscillations caused by an open channel for backscattering from an impurity and antiresonances in conductance when the Fermi energy matches the energy of the localized state created by an impurity.
Asymmetric 2D spatial beam filtering by photonic crystals
NASA Astrophysics Data System (ADS)
Gailevicius, D.; Purlys, V.; Maigyte, L.; Gaizauskas, E.; Peckus, M.; Gadonas, R.; Staliunas, K.
2016-04-01
Spatial filtering techniques are important for improving the spatial quality of light beams. Photonic crystals (PhCs) with a selective spatial (angular) transmittance can also provide spatial filtering with the added benefit transversal symmetries, submillimeter dimensions and monolithic integration in other devices, such as micro-lasers or semiconductor lasers. Workable bandgap PhC configurations require a modulated refractive index with period lengths that are approximately less than the wavelength of radiation. This imposes technical limitations, whereby the available direct laser write (DLW) fabrication techniques are limited in resolution and refractive index depth. If, however, a deflection mechanism is chosen instead, a functional filter PhC can be produced that is operational in the visible wavelength regime. For deflection based PhCs glass is an attractive choice as it is highly stable medium. 2D and 3D PhC filter variations have already been produced on soda-lime glass. However, little is known about how to control the scattering of PhCs when approaching the smallest period values. Here we look into the internal structure of the initially symmetric geometry 2D PhCs and associating it with the resulting transmittance spectra. By varying the DLW fabrication beam parameters and scanning algorithms, we show that such PhCs contain layers that are comprised of semi-tilted structure voxels. We show the appearance of asymmetry can be compensated in order to circumvent some negative effects at the cost of potentially maximum scattering efficiency.
2D Seismic Reflection Data across Central Illinois
Smith, Valerie; Leetaru, Hannes
2014-09-30
In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made
A Planar Quantum Transistor Based on 2D-2D Tunneling in Double Quantum Well Heterostructures
Baca, W.E.; Blount, M.A.; Hafich, M.J.; Lyo, S.K.; Moon, J.S.; Reno, J.L.; Simmons, J.A.; Wendt, J.R.
1998-12-14
We report on our work on the double electron layer tunneling transistor (DELTT), based on the gate-control of two-dimensional -- two-dimensional (2D-2D) tunneling in a double quantum well heterostructure. While previous quantum transistors have typically required tiny laterally-defined features, by contrast the DELTT is entirely planar and can be reliably fabricated in large numbers. We use a novel epoxy-bond-and-stop-etch (EBASE) flip-chip process, whereby submicron gating on opposite sides of semiconductor epitaxial layers as thin as 0.24 microns can be achieved. Because both electron layers in the DELTT are 2D, the resonant tunneling features are unusually sharp, and can be easily modulated with one or more surface gates. We demonstrate DELTTs with peak-to-valley ratios in the source-drain I-V curve of order 20:1 below 1 K. Both the height and position of the resonant current peak can be controlled by gate voltage over a wide range. DELTTs with larger subband energy offsets ({approximately} 21 meV) exhibit characteristics that are nearly as good at 77 K, in good agreement with our theoretical calculations. Using these devices, we also demonstrate bistable memories operating at 77 K. Finally, we briefly discuss the prospects for room temperature operation, increases in gain, and high-speed.
'Brukin2D': a 2D visualization and comparison tool for LC-MS data
Tsagkrasoulis, Dimosthenis; Zerefos, Panagiotis; Loudos, George; Vlahou, Antonia; Baumann, Marc; Kossida, Sophia
2009-01-01
Background Liquid Chromatography-Mass Spectrometry (LC-MS) is a commonly used technique to resolve complex protein mixtures. Visualization of large data sets produced from LC-MS, namely the chromatogram and the mass spectra that correspond to its compounds is the focus of this work. Results The in-house developed 'Brukin2D' software, built in Matlab 7.4, which is presented here, uses the compound data that are exported from the Bruker 'DataAnalysis' program, and depicts the mean mass spectra of all the chromatogram compounds from one LC-MS run, in one 2D contour/density plot. Two contour plots from different chromatograph runs can then be viewed in the same window and automatically compared, in order to find their similarities and differences. The results of the comparison can be examined through detailed mass quantification tables, while chromatogram compound statistics are also calculated during the procedure. Conclusion 'Brukin2D' provides a user-friendly platform for quick, easy and integrated view of complex LC-MS data. The software is available at . PMID:19534737
Inhibition of human cytochrome P450 2D6 (CYP2D6) by methadone.
Wu, D; Otton, S V; Sproule, B A; Busto, U; Inaba, T; Kalow, W; Sellers, E M
1993-01-01
1. In microsomes prepared from three human livers, methadone competitively inhibited the O-demethylation of dextromethorphan, a marker substrate for CYP2D6. The apparent Ki value of methadone ranged from 2.5 to 5 microM. 2. Two hundred and fifty-two (252) white Caucasians, including 210 unrelated healthy volunteers and 42 opiate abusers undergoing treatment with methadone were phenotyped using dextromethorphan as the marker drug. Although the frequency of poor metabolizers was similar in both groups, the extensive metabolizers among the opiate abusers tended to have higher O-demethylation metabolic ratios and to excrete less of the dose as dextromethorphan metabolites than control extensive metabolizer subjects. These data suggest inhibition of CYP2D6 by methadone in vivo as well. 3. Because methadone is widely used in the treatment of opiate abuse, inhibition of CYP2D6 activity in these patients might contribute to exaggerated response or unexpected toxicity from drugs that are substrates of this enzyme. PMID:8448065
Mass loss in 2D rotating stellar models
Lovekin, Caterine; Deupree, Bob
2010-10-05
Radiatively driven mass loss is an important factor in the evolution of massive stars . The mass loss rates depend on a number of stellar parameters, including the effective temperature and luminosity. Massive stars are also often rapidly rotating, which affects their structure and evolution. In sufficiently rapidly rotating stars, both the effective temperature and radius vary significantly as a function of latitude, and hence mass loss rates can vary appreciably between the poles and the equator. In this work, we discuss the addition of mass loss to a 2D stellar evolution code (ROTORC) and compare evolution sequences with and without mass loss. Preliminary results indicate that a full 2D calculation of mass loss using the local effective temperature and luminosity can significantly affect the distribution of mass loss in rotating main sequence stars. More mass is lost from the pole than predicted by 1D models, while less mass is lost at the equator. This change in the distribution of mass loss will affect the angular momentum loss, the surface temperature and luminosity, and even the interior structure of the star. After a single mass loss event, these effects are small, but can be expected to accumulate over the course of the main sequence evolution.
Magnetic gating of a 2D topological insulator.
Dang, Xiaoqian; Burton, J D; Tsymbal, Evgeny Y
2016-09-28
Deterministic control of transport properties through manipulation of spin states is one of the paradigms of spintronics. Topological insulators offer a new playground for exploring interesting spin-dependent phenomena. Here, we consider a ferromagnetic 'gate' representing a magnetic adatom coupled to the topologically protected edge state of a two-dimensional (2D) topological insulator to modulate the electron transmission of the edge state. Due to the locked spin and wave vector of the transport electrons the transmission across the magnetic gate depends on the mutual orientation of the adatom magnetic moment and the current. If the Fermi energy matches an exchange-split bound state of the adatom, the electron transmission can be blocked due to the full back scattering of the incident wave. This antiresonance behavior is controlled by the adatom magnetic moment orientation so that the transmission of the edge state can be changed from 1 to 0. Expanding this consideration to a ferromagnetic gate representing a 1D chain of atoms shows a possibility to control the spin-dependent current of a strip of a 2D topological insulator by magnetization orientation of the ferromagnetic gate. PMID:27437829
Magnetic gating of a 2D topological insulator
NASA Astrophysics Data System (ADS)
Dang, Xiaoqian; Burton, J. D.; Tsymbal, Evgeny Y.
2016-09-01
Deterministic control of transport properties through manipulation of spin states is one of the paradigms of spintronics. Topological insulators offer a new playground for exploring interesting spin-dependent phenomena. Here, we consider a ferromagnetic ‘gate’ representing a magnetic adatom coupled to the topologically protected edge state of a two-dimensional (2D) topological insulator to modulate the electron transmission of the edge state. Due to the locked spin and wave vector of the transport electrons the transmission across the magnetic gate depends on the mutual orientation of the adatom magnetic moment and the current. If the Fermi energy matches an exchange-split bound state of the adatom, the electron transmission can be blocked due to the full back scattering of the incident wave. This antiresonance behavior is controlled by the adatom magnetic moment orientation so that the transmission of the edge state can be changed from 1 to 0. Expanding this consideration to a ferromagnetic gate representing a 1D chain of atoms shows a possibility to control the spin-dependent current of a strip of a 2D topological insulator by magnetization orientation of the ferromagnetic gate.
2D Quantum Transport Modeling in Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, B.
2001-01-01
We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions, oxide tunneling and phase-breaking scattering are treated on an equal footing. Electron bandstructure is treated within the anisotropic effective mass approximation. We present the results of our simulations of MIT 25 and 90 nm "well-tempered" MOSFETs and compare them to those of classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. These results are consistent with 1D Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and subthreshold current has been studied. The shorter gate length device has an order of magnitude smaller leakage current than the longer gate length device without a significant trade-off in on-current.
NASA Astrophysics Data System (ADS)
Mangazeev, Vladimir V.; Batchelor, Murray T.; Bazhanov, Vladimir V.; Dudalev, Michael Yu
2009-01-01
The universal scaling function of the square lattice Ising model in a magnetic field is obtained numerically via Baxter's variational corner transfer matrix approach. The high precision numerical data are in perfect agreement with the remarkable field theory results obtained by Fonseca and Zamolodchikov, as well as with many previously known exact and numerical results for the 2D Ising model. This includes excellent agreement with analytic results for the magnetic susceptibility obtained by Orrick, Nickel, Guttmann and Perk. In general, the high precision of the numerical results underlines the potential and full power of the variational corner transfer matrix approach.
Correlated Electron Phenomena in 2D Materials
NASA Astrophysics Data System (ADS)
Lambert, Joseph G.
In this thesis, I present experimental results on coherent electron phenomena in layered two-dimensional materials: single layer graphene and van der Waals coupled 2D TiSe2. Graphene is a two-dimensional single-atom thick sheet of carbon atoms first derived from bulk graphite by the mechanical exfoliation technique in 2004. Low-energy charge carriers in graphene behave like massless Dirac fermions, and their density can be easily tuned between electron-rich and hole-rich quasiparticles with electrostatic gating techniques. The sharp interfaces between regions of different carrier densities form barriers with selective transmission, making them behave as partially reflecting mirrors. When two of these interfaces are set at a separation distance within the phase coherence length of the carriers, they form an electronic version of a Fabry-Perot cavity. I present measurements and analysis of multiple Fabry-Perot modes in graphene with parallel electrodes spaced a few hundred nanometers apart. Transition metal dichalcogenide (TMD) TiSe2 is part of the family of materials that coined the term "materials beyond graphene". It contains van der Waals coupled trilayer stacks of Se-Ti-Se. Many TMD materials exhibit a host of interesting correlated electronic phases. In particular, TiSe2 exhibits chiral charge density waves (CDW) below TCDW ˜ 200 K. Upon doping with copper, the CDW state gets suppressed with Cu concentration, and CuxTiSe2 becomes superconducting with critical temperature of T c = 4.15 K. There is still much debate over the mechanisms governing the coexistence of the two correlated electronic phases---CDW and superconductivity. I will present some of the first conductance spectroscopy measurements of proximity coupled superconductor-CDW systems. Measurements reveal a proximity-induced critical current at the Nb-TiSe2 interfaces, suggesting pair correlations in the pure TiSe2. The results indicate that superconducting order is present concurrently with CDW in
MDMA, methamphetamine, and CYP2D6 pharmacogenetics: what is clinically relevant?
de la Torre, Rafael; Yubero-Lahoz, Samanta; Pardo-Lozano, Ricardo; Farré, Magí
2012-01-01
In vitro human studies show that the metabolism of most amphetamine-like psychostimulants is regulated by the polymorphic cytochrome P450 isozyme CYP2D6. Two compounds, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA), were selected as archetypes to discuss the translation and clinical significance of in vitro to in vivo findings. Both compounds were chosen based on their differential interaction with CYP2D6 and their high abuse prevalence in society. Methamphetamine behaves as both a weak substrate and competitive inhibitor of CYP2D6, while MDMA acts as a high affinity substrate and potent mechanism-based inhibitor (MBI) of the enzyme. The MBI behavior of MDMA on CYP2D6 implies that subjects, irrespective of their genotype/phenotype, are phenocopied to the poor metabolizer (PM) phenotype. The fraction of metabolic clearance regulated by CYP2D6 for both drugs is substantially lower than expected from in vitro studies. Other isoenzymes of cytochrome P450 and a relevant contribution of renal excretion play a part in their clearance. These facts tune down the potential contribution of CYP2D6 polymorphism in the clinical outcomes of both substances. Globally, the clinical relevance of CYP2D6 polymorphism is lower than that predicted by in vitro studies. PMID:23162568
CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping
Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea
2016-01-01
TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact
CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.
Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea
2015-01-01
TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer
Schnitzer, J E; Lambrakis, K C
1991-09-21
Understanding the physicochemical basis of the interaction of molecules with lipid bilayers is fundamental to membrane biology. In this study, a new, three-dimensional numerical solution of the full Poisson equation including local dielectric variation is developed using finite difference techniques in order to model electrostatic interactions of charged molecules with a non-uniform dielectric. This solution is used to describe the electric field and electrostatic potential profile of a charged molecule interacting with a phospholipid bilayer in a manner consistent with the known composition and structure of the membrane. Furthermore, the Born interaction energy is then calculated by appropriate integration of the electric field over whole space. Numerical computations indicate that the electrostatic potential profile surrounding a charge molecule and its resultant Born interaction energy are a function of molecular position within the membrane and change most significantly within the polar region of the bilayer. The maximum interaction energy is observed when the charge is placed at the center of the hydrophobic core of the membrane and is strongly dependent on the size of the charge and on the thickness of the hydrocarbon core of the bilayer. The numerical results of this continuum model are compared with various analytical approximations for the Born energy including models established for discontinuous slab dielectrics. The calculated energies agree with the well-known Born analytical expression only when the charge is located near the center of a hydrocarbon core of greater than 60 A in thickness. The Born-image model shows excellent agreement with the numerical results only when modified to include an appropriate effective thickness of the low dielectric region. In addition, a newly derived approximation which considers the local mean dielectric provides a simple and continuous solution that also agrees well with the numerical results.
Novel antenna coupled 2D plasmonic terahertz detection.
Allen, Jim; Dyer, Greg; Reno, John Louis; Shaner, Eric Arthur
2010-03-01
Resonant plasmonic detectors are potentially important for terahertz (THz) spectroscopic imaging. We have fabricated and characterized antenna coupled detectors that integrate a broad-band antenna, which improves coupling of THz radiation. The vertex of the antenna contains the tuning gates and the bolometric barrier gate. Incident THz radiation may excite 2D plasmons with wave-vectors defined by either a periodic grating gate or a plasmonic cavity determined by ohmic contacts and gate terminals. The latter approach of exciting plasmons in a cavity defined by a short micron-scale channel appears most promising. With this short-channel geometry, we have observed multiple harmonics of THz plasmons. At 20 K with detector bias optimized we report responsivity on resonance of 2.5 kV/W and an NEP of 5 x 10{sup -10} W/Hz{sup 1/2}.
Hou, Dan; Ma, Yong-Tao; Zhang, Xiao-Long; Li, Hui
2016-01-01
The origin and strength of intra- and inter-molecular vibrational coupling is difficult to probe by direct experimental observations. However, explicitly including or not including some specific intramolecular vibrational modes to study intermolecular interaction provides a precise theoretical way to examine the effects of anharmonic coupling between modes. In this work, a full-dimension intra- and inter-molecular ab initio potential energy surface (PES) for H2O-Ar, which explicitly incorporates interdependence on the intramolecular (Q1, Q2, Q3) normal-mode coordinates of the H2O monomer, has been calculated. In addition, four analytic vibrational-quantum-state-specific PESs are obtained by least-squares fitting vibrationally averaged interaction energies for the (v1, v2, v3) = (0, 0, 0), (0, 0, 1), (1, 0, 0), (0, 1, 0) states of H2O to the three-dimensional Morse/long-range potential function. Each vibrationally averaged PES fitted to 442 points has root-mean-square (rms) deviation smaller than 0.15 cm(-1), and required only 58 parameters. With the 3D PESs of H2O-Ar dimer system, we employed the combined radial discrete variable representation/angular finite basis representation method and Lanczos algorithm to calculate rovibrational energy levels. This showed that the resulting vibrationally averaged PESs provide good representations of the experimental infrared data, with rms discrepancies smaller than 0.02 cm(-1) for all three rotational branches of the asymmetric stretch fundamental transitions. The infrared band origin shifts associated with three fundamental bands of H2O in H2O-Ar complex are predicted for the first time and are found to be in good agreement with the (extrapolated) experimental values. Upon introduction of additional intramolecular degrees of freedom into the intermolecular potential energy surface, there is clear spectroscopic evidence of intra- and intermolecular vibrational couplings.
Optimum design of 2D micro-angle sensor
NASA Astrophysics Data System (ADS)
Liu, Qinggang; Zhao, Heng; Lou, Xiaona; Jiang, Ningchuan; Hu, Xiaotang
2008-12-01
To improve dynamic measurement performance and resolution, an optimum design on two-dimensional (2D) micro-angle sensor based on optical internal-reflection method via critical-angle refractive index measurement is presented in the paper. The noise signals were filtered effectively by modulating laser-driven and demodulating in signal proceeding. The system's accuracy and response speed are improved further by using 16-bit high-precision AD converter and MSP430 CPU which present with a high-speed performance during signals processes such as fitting angle-voltage curve through specific arithmetic, full range and zero point calibration, filter, scaling transformation etc. The experiment results indicated that, dynamic signal measurement range can be up to +/-600arcsec, the measurement resolution can be better than 0.1arcsec, and the repeatability could be better than +/-0.5arcsec.
NASA Technical Reports Server (NTRS)
Johnson, F. T.; Samant, S. S.; Bieterman, M. B.; Melvin, R. G.; Young, D. P.; Bussoletti, J. E.; Hilmes, C. L.
1992-01-01
A new computer program, called TranAir, for analyzing complex configurations in transonic flow (with subsonic or supersonic freestream) was developed. This program provides accurate and efficient simulations of nonlinear aerodynamic flows about arbitrary geometries with the ease and flexibility of a typical panel method program. The numerical method implemented in TranAir is described. The method solves the full potential equation subject to a set of general boundary conditions and can handle regions with differing total pressure and temperature. The boundary value problem is discretized using the finite element method on a locally refined rectangular grid. The grid is automatically constructed by the code and is superimposed on the boundary described by networks of panels; thus no surface fitted grid generation is required. The nonlinear discrete system arising from the finite element method is solved using a preconditioned Krylov subspace method embedded in an inexact Newton method. The solution is obtained on a sequence of successively refined grids which are either constructed adaptively based on estimated solution errors or are predetermined based on user inputs. Many results obtained by using TranAir to analyze aerodynamic configurations are presented.
Chen, Liuyang; Shao, Kejie; Chen, Jun; Yang, Minghui; Zhang, Dong H
2016-05-21
This work performs a time-dependent wavepacket study of the H2 + C2H → H + C2H2 reaction on a new ab initio potential energy surface (PES). The PES is constructed using neural network method based on 68 478 geometries with energies calculated at UCCSD(T)-F12a/aug-cc-pVTZ level and covers H2 + C2H↔H + C2H2, H + C2H2 → HCCH2, and HCCH2 radial isomerization reaction regions. The reaction dynamics of H2 + C2H → H + C2H2 are investigated using full-dimensional quantum dynamics method. The initial-state selected reaction probabilities are calculated for reactants in eight vibrational states. The calculated results showed that the H2 vibrational excitation predominantly enhances the reactivity while the excitation of bending mode of C2H slightly inhibits the reaction. The excitations of two stretching modes of C2H molecule have negligible effect on the reactivity. The integral cross section is calculated with J-shift approximation and the mode selectivity in this reaction is discussed. The rate constants over 200-2000 K are calculated and agree well with the experimental measured values.
NASA Astrophysics Data System (ADS)
Suzuki, Shugo; Ariizumi, Toshihiro; Li, Ming-Fang
2009-07-01
We study the X-ray magnetic circular dichroism (XMCD) spectra at the U M4,5 and N4,5 edges of uranium monochalcogenides, UX where X=S, Se, and Te, examining the applicability of the XMCD sum rules to UX by the fully relativistic full-potential linear-combination-of-atomic-orbitals (LCAO) method based on the density functional theory. To extract the transitions relevant to the sum-rule analysis, we employ the Mulliken population analysis (MPA). Using the MPA, the orbital sum rule is found to be valid to 10-20% for the M4,5 edges and valid to 5-15% for the N4,5 edges. On the other hand, the spin sum rule is found to be valid to 10-20% for the M4,5 edges whereas valid to 30-35% for the N4,5 edges. Furthermore, it is found that the calculated XMCD spectra are consistent with a recent experimental observation that the intensity of the N4,5 XMCD signal is comparable to that of the M4,5 XMCD signal although contradicting a previous theoretical prediction that the XMCD intensity at the N4,5 edges is one order of magnitude smaller than that at the M4,5 edges.
LaPara, Timothy M; Hope Wilkinson, Katheryn; Strait, Jacqueline M; Hozalski, Raymond M; Sadowksy, Michael J; Hamilton, Matthew J
2015-10-01
The bacterial community composition of the full-scale biologically active, granular activated carbon (BAC) filters operated at the St. Paul Regional Water Services (SPRWS) was investigated using Illumina MiSeq analysis of PCR-amplified 16S rRNA gene fragments. These bacterial communities were consistently diverse (Shannon index, >4.4; richness estimates, >1,500 unique operational taxonomic units [OTUs]) throughout the duration of the 12-month study period. In addition, only modest shifts in the quantities of individual bacterial populations were observed; of the 15 most prominent OTUs, the most highly variable population (a Variovorax sp.) modulated less than 13-fold over time and less than 8-fold from filter to filter. The most prominent population in the profiles was a Nitrospira sp., representing 13 to 21% of the community. Interestingly, very few of the known ammonia-oxidizing bacteria (AOB; <0.07%) and no ammonia-oxidizing Archaea were detected in the profiles. Quantitative PCR of amoA genes, however, suggested that AOB were prominent in the bacterial communities (amoA/16S rRNA gene ratio, 1 to 10%). We conclude, therefore, that the BAC filters at the SPRWS potentially contained significant numbers of unidentified and novel ammonia-oxidizing microorganisms that possess amoA genes similar to those of previously described AOB. PMID:26209671
Hope Wilkinson, Katheryn; Strait, Jacqueline M.; Hozalski, Raymond M.; Sadowksy, Michael J.; Hamilton, Matthew J.
2015-01-01
The bacterial community composition of the full-scale biologically active, granular activated carbon (BAC) filters operated at the St. Paul Regional Water Services (SPRWS) was investigated using Illumina MiSeq analysis of PCR-amplified 16S rRNA gene fragments. These bacterial communities were consistently diverse (Shannon index, >4.4; richness estimates, >1,500 unique operational taxonomic units [OTUs]) throughout the duration of the 12-month study period. In addition, only modest shifts in the quantities of individual bacterial populations were observed; of the 15 most prominent OTUs, the most highly variable population (a Variovorax sp.) modulated less than 13-fold over time and less than 8-fold from filter to filter. The most prominent population in the profiles was a Nitrospira sp., representing 13 to 21% of the community. Interestingly, very few of the known ammonia-oxidizing bacteria (AOB; <0.07%) and no ammonia-oxidizing Archaea were detected in the profiles. Quantitative PCR of amoA genes, however, suggested that AOB were prominent in the bacterial communities (amoA/16S rRNA gene ratio, 1 to 10%). We conclude, therefore, that the BAC filters at the SPRWS potentially contained significant numbers of unidentified and novel ammonia-oxidizing microorganisms that possess amoA genes similar to those of previously described AOB. PMID:26209671
LaPara, Timothy M; Hope Wilkinson, Katheryn; Strait, Jacqueline M; Hozalski, Raymond M; Sadowksy, Michael J; Hamilton, Matthew J
2015-10-01
The bacterial community composition of the full-scale biologically active, granular activated carbon (BAC) filters operated at the St. Paul Regional Water Services (SPRWS) was investigated using Illumina MiSeq analysis of PCR-amplified 16S rRNA gene fragments. These bacterial communities were consistently diverse (Shannon index, >4.4; richness estimates, >1,500 unique operational taxonomic units [OTUs]) throughout the duration of the 12-month study period. In addition, only modest shifts in the quantities of individual bacterial populations were observed; of the 15 most prominent OTUs, the most highly variable population (a Variovorax sp.) modulated less than 13-fold over time and less than 8-fold from filter to filter. The most prominent population in the profiles was a Nitrospira sp., representing 13 to 21% of the community. Interestingly, very few of the known ammonia-oxidizing bacteria (AOB; <0.07%) and no ammonia-oxidizing Archaea were detected in the profiles. Quantitative PCR of amoA genes, however, suggested that AOB were prominent in the bacterial communities (amoA/16S rRNA gene ratio, 1 to 10%). We conclude, therefore, that the BAC filters at the SPRWS potentially contained significant numbers of unidentified and novel ammonia-oxidizing microorganisms that possess amoA genes similar to those of previously described AOB.
Wang, Xu; Li, Meiyan; Liu, Junxin; Qu, Jiuhui
2016-07-01
Millions of tons of waste activated sludge (WAS) produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants (WWTPs) of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples (up to 9478mg/L), followed by endogenous residues (6736mg/L), extracellular polymeric substances (2088mg/L), and intracellular storage products (464mg/L) among others. Moreover, significant differences (p<0.05) were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge.
NASA Astrophysics Data System (ADS)
Amari, S.; Bouhafs, B.
2016-09-01
Based on the first-principles methods, the structural, elastic, electronic, properties and magnetic ordering of californium monopnictides CfX (X = P) have been studied using the full-potential augmented plane wave plus local orbitals (FP-L/APW + lo) method within the framework of density functional theory (DFT). The electronic exchange correlation energy is described by generalized gradient approximation GGA and GGA+U (U is the Hubbard correction). The GGA+U method is applied to the rare-earth 5f states. We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. In order to gain further information, we have calculated Young's modulus, shear modulus, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. The results mainly show that californium monopnictides CfX (X = P) have an antiferromagnetic spin ordering. Density of states (DOS) and charge densities for both compounds are also computed in the NaCl (B1) structure.
VizieR Online Data Catalog: c2d Spitzer final data release (DR4) (Evans+, 2003)
NASA Astrophysics Data System (ADS)
Evans, N. J., II; Allen, L. E.; Blake, G. A.; Boogert, A. C. A.; Bourke, T.; Harvey, P. M.; Kessler, J. E.; Koerner, D. W.; Lee, C. W.; Mundy, L. G.; Myers, P. C.; Padgett, D. L.; Pontoppidan, K.; Sargent, A. I.; Stapelfeldt, K. R.; van Dishoeck, E. F.; Young, C. H.; Young, K. E.
2014-05-01
This is the final delivery (DR4, Fall 2006 and Fall 2007) of the Spitzer Space Telescope "From Molecular Cores to Planet-Forming Disks" (c2d) Legacy Project. The data are also available as Enhanced Products from the Spitzer Science Center (SSC). c2d has delivered 867 catalogs. IRSA has merged these delivered catalogs into four groups - Clouds, Off-Cloud, Cores, Stars - and serves them through the general catalog search engine Gator. Many of the delivered catalogs, images and spectra are accessible through IRSA's general search service, Atlas. As a service to its users, the CDS has downloaded a dataset containing most of the c2d data (but not all columns) from the IRSA archive. The individual catalogs are listed below: C2D Fall '07 Full CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 High Reliability (HREL) CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 candidate Young Stellar Objects (YSO) CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 Full OFF-CLOUD Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 candidate Young Stellar Objects (YSO) OFF-CLOUD Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 Full CORES Catalog C2D Fall '07 candidate Young Stellar Objects (YSO) CORES Catalog C2D Fall '07 Full STARS Catalog C2D Fall '07 candidate Young Stellar Objects (YSO) STARS Catalog These tables have been merged into a single table at CDS. All three SIRTF instruments (Infrared Array Camera [IRAC], Multiband Imaging Photometer for SIRTF [MIPS], and Infrared Spectrograph [IRS]) were used to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. (1 data file).
Unusual dimensionality effects and surface charge density in 2D Mg(OH)2
Suslu, Aslihan; Wu, Kedi; Sahin, Hasan; Chen, Bin; Yang, Sijie; Cai, Hui; Aoki, Toshihiro; Horzum, Seyda; Kang, Jun; Peeters, Francois M.; Tongay, Sefaattin
2016-01-01
We present two-dimensional Mg(OH)2 sheets and their vertical heterojunctions with CVD-MoS2 for the first time as flexible 2D insulators with anomalous lattice vibration and chemical and physical properties. New hydrothermal crystal growth technique enabled isolation of environmentally stable monolayer Mg(OH)2 sheets. Raman spectroscopy and vibrational calculations reveal that the lattice vibrations of Mg(OH)2 have fundamentally different signature peaks and dimensionality effects compared to other 2D material systems known to date. Sub-wavelength electron energy-loss spectroscopy measurements and theoretical calculations show that Mg(OH)2 is a 6 eV direct-gap insulator in 2D, and its optical band gap displays strong band renormalization effects from monolayer to bulk, marking the first experimental confirmation of confinement effects in 2D insulators. Interestingly, 2D-Mg(OH)2 sheets possess rather strong surface polarization (charge) effects which is in contrast to electrically neutral h-BN materials. Using 2D-Mg(OH)2 sheets together with CVD-MoS2 in the vertical stacking shows that a strong change transfer occurs from n-doped CVD-MoS2 sheets to Mg(OH)2, naturally depleting the semiconductor, pushing towards intrinsic doping limit and enhancing overall optical performance of 2D semiconductors. Results not only establish unusual confinement effects in 2D-Mg(OH)2, but also offer novel 2D-insulating material with unique physical, vibrational, and chemical properties for potential applications in flexible optoelectronics. PMID:26846617
Distribution of CYP2D6 alleles and phenotypes in the Brazilian population.
Friedrich, Deise C; Genro, Júlia P; Sortica, Vinicius A; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D J; dos Santos, Andrea K Ribeiro; Romano-Silva, Marco A; Hutz, Mara H
2014-01-01
The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions. PMID:25329392
Unusual dimensionality effects and surface charge density in 2D Mg(OH)2
NASA Astrophysics Data System (ADS)
Suslu, Aslihan; Wu, Kedi; Sahin, Hasan; Chen, Bin; Yang, Sijie; Cai, Hui; Aoki, Toshihiro; Horzum, Seyda; Kang, Jun; Peeters, Francois M.; Tongay, Sefaattin
2016-02-01
We present two-dimensional Mg(OH)2 sheets and their vertical heterojunctions with CVD-MoS2 for the first time as flexible 2D insulators with anomalous lattice vibration and chemical and physical properties. New hydrothermal crystal growth technique enabled isolation of environmentally stable monolayer Mg(OH)2 sheets. Raman spectroscopy and vibrational calculations reveal that the lattice vibrations of Mg(OH)2 have fundamentally different signature peaks and dimensionality effects compared to other 2D material systems known to date. Sub-wavelength electron energy-loss spectroscopy measurements and theoretical calculations show that Mg(OH)2 is a 6 eV direct-gap insulator in 2D, and its optical band gap displays strong band renormalization effects from monolayer to bulk, marking the first experimental confirmation of confinement effects in 2D insulators. Interestingly, 2D-Mg(OH)2 sheets possess rather strong surface polarization (charge) effects which is in contrast to electrically neutral h-BN materials. Using 2D-Mg(OH)2 sheets together with CVD-MoS2 in the vertical stacking shows that a strong change transfer occurs from n-doped CVD-MoS2 sheets to Mg(OH)2, naturally depleting the semiconductor, pushing towards intrinsic doping limit and enhancing overall optical performance of 2D semiconductors. Results not only establish unusual confinement effects in 2D-Mg(OH)2, but also offer novel 2D-insulating material with unique physical, vibrational, and chemical properties for potential applications in flexible optoelectronics.
Distribution of CYP2D6 alleles and phenotypes in the Brazilian population.
Friedrich, Deise C; Genro, Júlia P; Sortica, Vinicius A; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D J; dos Santos, Andrea K Ribeiro; Romano-Silva, Marco A; Hutz, Mara H
2014-01-01
The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions.
Distribution of CYP2D6 Alleles and Phenotypes in the Brazilian Population
Sortica, Vinicius A.; Suarez-Kurtz, Guilherme; de Moraes, Maria Elizabete; Pena, Sergio D. J.; dos Santos, Ândrea K. Ribeiro; Romano-Silva, Marco A.; Hutz, Mara H.
2014-01-01
Abstract The CYP2D6 enzyme is one of the most important members of the cytochrome P450 superfamily. This enzyme metabolizes approximately 25% of currently prescribed medications. The CYP2D6 gene presents a high allele heterogeneity that determines great inter-individual variation. The aim of this study was to evaluate the variability of CYP2D6 alleles, genotypes and predicted phenotypes in Brazilians. Eleven single nucleotide polymorphisms and CYP2D6 duplications/multiplications were genotyped by TaqMan assays in 1020 individuals from North, Northeast, South, and Southeast Brazil. Eighteen CYP2D6 alleles were identified in the Brazilian population. The CYP2D6*1 and CYP2D6*2 alleles were the most frequent and widely distributed in different geographical regions of Brazil. The highest number of CYPD6 alleles observed was six and the frequency of individuals with more than two copies ranged from 6.3% (in Southern Brazil) to 10.2% (Northern Brazil). The analysis of molecular variance showed that CYP2D6 is homogeneously distributed across different Brazilian regions and most of the differences can be attributed to inter-individual differences. The most frequent predicted metabolic status was EM (83.5%). Overall 2.5% and 3.7% of Brazilians were PMs and UMs respectively. Genomic ancestry proportions differ only in the prevalence of intermediate metabolizers. The IM predicted phenotype is associated with a higher proportion of African ancestry and a lower proportion of European ancestry in Brazilians. PM and UM classes did not vary among regions and/or ancestry proportions therefore unique CYP2D6 testing guidelines for Brazilians are possible and could potentially avoid ineffective or adverse events outcomes due to drug prescriptions. PMID:25329392
Presynaptic GluN2D receptors detect glutamate spillover and regulate cerebellar GABA release.
Dubois, Christophe J; Lachamp, Philippe M; Sun, Lu; Mishina, Masayoshi; Liu, Siqiong June
2016-01-01
Glutamate directly activates N-methyl-d-aspartate (NMDA) receptors on presynaptic inhibitory interneurons and enhances GABA release, altering the excitatory-inhibitory balance within a neuronal circuit. However, which class of NMDA receptors is involved in the detection of glutamate spillover is not known. GluN2D subunit-containing NMDA receptors are ideal candidates as they exhibit a high affinity for glutamate. We now show that cerebellar stellate cells express both GluN2B and GluN2D NMDA receptor subunits. Genetic deletion of GluN2D subunits prevented a physiologically relevant, stimulation-induced, lasting increase in GABA release from stellate cells [long-term potentiation of inhibitory transmission (I-LTP)]. NMDA receptors are tetramers composed of two GluN1 subunits associated to either two identical subunits (di-heteromeric receptors) or to two different subunits (tri-heteromeric receptors). To determine whether tri-heteromeric GluN2B/2D NMDA receptors mediate I-LTP, we tested the prediction that deletion of GluN2D converts tri-heteromeric GluN2B/2D to di-heteromeric GluN2B NMDA receptors. We find that prolonged stimulation rescued I-LTP in GluN2D knockout mice, and this was abolished by GluN2B receptor blockers that failed to prevent I-LTP in wild-type mice. Therefore, NMDA receptors that contain both GluN2D and GluN2B mediate the induction of I-LTP. Because these receptors are not present in the soma and dendrites, presynaptic tri-heteromeric GluN2B/2D NMDA receptors in inhibitory interneurons are likely to mediate the cross talk between excitatory and inhibitory transmission.
Few-layer III-VI and IV-VI 2D semiconductor transistors
NASA Astrophysics Data System (ADS)
Sucharitakul, Sukrit; Liu, Mei; Kumar, Rajesh; Sankar, Raman; Chou, Fang C.; Chen, Yit-Tsong; Gao, Xuan
Since the discovery of atomically thin graphene, a large variety of exfoliable 2D materials have been thoroughly explored for their exotic transport behavior and promises in technological breakthroughs. While most attention on 2D materials beyond graphene is focused on transition metal-dichalcogenides, relatively less attention is paid to layered III-VI and IV-VI semiconductors such as InSe, SnSe etc which bear stronger potential as 2D materials with high electron mobility or thermoelectric figure of merit. We will discuss our recent work on few-layer InSe 2D field effect transistors which exhibit carrier mobility approaching 1000 cm2/Vs and ON-OFF ratio exceeding 107 at room temperature. In addition, the fabrication and device performance of transistors made of mechanically exfoliated multilayer IV-VI semiconductor SnSe and SnSe2 will be discussed.
Haik, Josef; Nardini, Gil; Goldman, Noga; Galore-Haskel, Gilli; Harats, Moti; Zilinsky, Isaac; Weissman, Oren; Schachter, Jacob; Winkler, Eyal; Markel, Gal
2016-01-19
Immune suppression following major thermal injury directly impacts the recovery potential. Limited data from past reports indicate that natural killer cells might be suppressed due to a putative soluble factor that has remained elusive up to date. Here we comparatively study cohorts of patients with Major and Non-Major Burns as well as healthy donors. MICB and ULBP1 are stress ligands of NKG2D that can be induced by heat stress. Remarkably, serum concentration levels of MICB and ULBP1 are increased by 3-fold and 20-fold, respectively, already within 24h post major thermal injury, and are maintained high for 28 days. In contrast, milder thermal injuries do not similarly enhance the serum levels of MICB and ULBP1. This kinetics coincides with a significant downregulation of NKG2D expression among peripheral blood NK cells. Downregulation of NKG2D by high concentration of soluble MICB occurs in cancer patients and during normal pregnancy due to over production by cancer cells or extravillous trophoblasts, respectively, as an active immune-evasion mechanism. In burn patients this seems an incidental outcome of extensive thermal injury, leading to reduced NKG2D expression. Enhanced susceptibility of these patients to opportunistic viral infections, particularly herpes viruses, could be explained by the reduced NKG2D expression. Further studies are warranted for translation into innovative diagnostic or therapeutic technologies. PMID:26745675
Installed Transonic 2D Nozzle Nacelle Boattail Drag Study
NASA Technical Reports Server (NTRS)
Malone, Michael B.; Peavey, Charles C.
1999-01-01
The Transonic Nozzle Boattail Drag Study was initiated in 1995 to develop an understanding of how external nozzle transonic aerodynamics effect airplane performance and how strongly those effects are dependent on nozzle configuration (2D vs. axisymmetric). MDC analyzed the axisymmetric nozzle. Boeing subcontracted Northrop-Grumman to analyze the 2D nozzle. AU participants analyzed the AGARD nozzle as a check-out and validation case. Once the codes were checked out and the gridding resolution necessary for modeling the separated flow in this region determined, the analysis moved to the installed wing/body/nacelle/diverter cases. The boat tail drag validation case was the AGARD B.4 rectangular nozzle. This test case offered both test data and previous CFD analyses for comparison. Results were obtained for test cases B.4.1 (M=0.6) and B.4.2 (M=0.938) and compared very well with the experimental data. Once the validation was complete a CFD grid was constructed for the full Ref. H configuration (wing/body/nacelle/diverter) using a combination of patched and overlapped (Chimera) grids. This was done to ensure that the grid topologies and density would be adequate for the full model. The use of overlapped grids allowed the same grids from the full configuration model to be used for the wing/body alone cases, thus eliminating the risk of grid differences affecting the determination of the installation effects. Once the full configuration model was run and deemed to be suitable the nacelle/diverter grids were removed and the wing/body analysis performed. Reference H wing/body results were completed for M=0.9 (a=0.0, 2.0, 4.0, 6.0 and 8.0), M=1.1 (a=4.0 and 6.0) and M=2.4 (a=0.0, 2.0, 4.4, 6.0 and 8.0). Comparisons of the M=0.9 and M=2.4 cases were made with available wind tunnel data and overall comparisons were good. The axi-inlet/2D nozzle nacelle was analyzed isolated. The isolated nacelle data coupled with the wing/body result enabled the interference effects of the
NASA Astrophysics Data System (ADS)
Majumder, Moumita; Hegger, Samuel E.; Dawes, Richard; Manzhos, Sergei; Wang, Xiao-Gang; Tucker, Carrington, Jr.; Li, Jun; Guo, Hua
2015-07-01
A data-set of nearly 100,000 symmetry unique multi-configurational ab initio points for methane were generated at the (AE)-MRCI-F12(Q)/CVQZ-F12 level, including energies beyond 30,000 cm-1 above the minimum and fit into potential energy surfaces (PESs) by several permutation invariant schemes. A multi-expansion interpolative fit combining interpolating moving least squares (IMLS) fitting and permutation invariant polynomials (PIP) was able to fit the complete data-set to a root-mean-square deviation of 1.0 cm-1 and thus was used to benchmark the other fitting methods. The other fitting methods include a single PIP expansion and two neural network (NN) based approaches, one of which combines NN with PIP. Full-dimensional variational vibrational calculations using a contracted-iterative method (and a Lanczos eigensolver) were used to assess the spectroscopic accuracy of the electronic structure method. The results show that the NN-based fitting approaches are able to fit the data-set remarkably accurately with the PIP-NN method producing levels in remarkably close agreement with the PIP-IMLS benchmark. The (AE)-MRCI-F12(Q)/CVQZ-F12 electronic structure method produces vibrational levels of near spectroscopic accuracy and a superb equilibrium geometry. The levels are systematically slightly too high, beginning at ∼ 1-2 cm-1 above the fundamentals and becoming correspondingly higher for overtones. The PES is therefore suitable for small ab initio or empirical corrections and since it is based on a multi-reference method, can be extended to represent dynamically relevant dissociation channels.
Janke, Svenja M; Auerbach, Daniel J; Wodtke, Alec M; Kandratsenka, Alexander
2015-09-28
We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H-Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.
Janke, Svenja M.; Auerbach, Daniel J.; Kandratsenka, Alexander; Wodtke, Alec M.
2015-09-28
We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H–Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.
Wang, Bin; Lou, Zhichao; Zhang, Haiqian; Xu, Bingqian
2016-03-21
The electrostatic surface potential (ESP) of prion oligomers has critical influences on the aggregating processes of the prion molecules. The atomic force microscopy (AFM) and structural simulation were combined to investigate the molecular basis of the full-length human recombinant prion oligomerization on mica surfaces. The high resolution non-intrusive AFM images showed that the prion oligomers formed different patterns on mica surfaces at different buffer pH values. The basic binding units for the large oligomers were determined to be prion momoners (Ms), dimers (Ds), and trimers (Ts). The forming of the D and T units happened through the binding of hydrophobic β-sheets of the M units. In contrast, the α-helices of these M, D, and T units were the binding areas for the formation of large oligomers. At pH 4.5, the binding units M, D, and T showed clear polarized ESP distributions on the surface domains, while at pH 7.0, they showed more evenly distributed ESPs. Based on the conformations of oligomers observed from AFM images, the D and T units were more abundantly on mica surface at pH 4.5 because the ESP re-distribution of M units helped to stabilize these larger oligomers. The amino acid side chains involved in the binding interfaces were stabilized by hydrogen bonds and electrostatic interactions. The detailed analysis of the charged side chains at pH 4.5 indicated that the polarized ESPs induced the aggregations among M, D, and T to form larger oligomers. Therefore, the hydrogen bonds and electrostatic interactions worked together to form the stabilized prion oligomers. PMID:27004887
NASA Astrophysics Data System (ADS)
Wang, Bin; Lou, Zhichao; Zhang, Haiqian; Xu, Bingqian
2016-03-01
The electrostatic surface potential (ESP) of prion oligomers has critical influences on the aggregating processes of the prion molecules. The atomic force microscopy (AFM) and structural simulation were combined to investigate the molecular basis of the full-length human recombinant prion oligomerization on mica surfaces. The high resolution non-intrusive AFM images showed that the prion oligomers formed different patterns on mica surfaces at different buffer pH values. The basic binding units for the large oligomers were determined to be prion momoners (Ms), dimers (Ds), and trimers (Ts). The forming of the D and T units happened through the binding of hydrophobic β-sheets of the M units. In contrast, the α-helices of these M, D, and T units were the binding areas for the formation of large oligomers. At pH 4.5, the binding units M, D, and T showed clear polarized ESP distributions on the surface domains, while at pH 7.0, they showed more evenly distributed ESPs. Based on the conformations of oligomers observed from AFM images, the D and T units were more abundantly on mica surface at pH 4.5 because the ESP re-distribution of M units helped to stabilize these larger oligomers. The amino acid side chains involved in the binding interfaces were stabilized by hydrogen bonds and electrostatic interactions. The detailed analysis of the charged side chains at pH 4.5 indicated that the polarized ESPs induced the aggregations among M, D, and T to form larger oligomers. Therefore, the hydrogen bonds and electrostatic interactions worked together to form the stabilized prion oligomers.
Wan, Yong; Otsuna, Hideo; Chien, Chi-Bin; Hansen, Charles
2013-01-01
2D image space methods are processing methods applied after the volumetric data are projected and rendered into the 2D image space, such as 2D filtering, tone mapping and compositing. In the application domain of volume visualization, most 2D image space methods can be carried out more efficiently than their 3D counterparts. Most importantly, 2D image space methods can be used to enhance volume visualization quality when applied together with volume rendering methods. In this paper, we present and discuss the applications of a series of 2D image space methods as enhancements to confocal microscopy visualizations, including 2D tone mapping, 2D compositing, and 2D color mapping. These methods are easily integrated with our existing confocal visualization tool, FluoRender, and the outcome is a full-featured visualization system that meets neurobiologists’ demands for qualitative analysis of confocal microscopy data. PMID:23584131
Wan, Yong; Otsuna, Hideo; Chien, Chi-Bin; Hansen, Charles
2012-01-01
2D image space methods are processing methods applied after the volumetric data are projected and rendered into the 2D image space, such as 2D filtering, tone mapping and compositing. In the application domain of volume visualization, most 2D image space methods can be carried out more efficiently than their 3D counterparts. Most importantly, 2D image space methods can be used to enhance volume visualization quality when applied together with volume rendering methods. In this paper, we present and discuss the applications of a series of 2D image space methods as enhancements to confocal microscopy visualizations, including 2D tone mapping, 2D compositing, and 2D color mapping. These methods are easily integrated with our existing confocal visualization tool, FluoRender, and the outcome is a full-featured visualization system that meets neurobiologists' demands for qualitative analysis of confocal microscopy data.
Synthetic Covalent and Non-Covalent 2D Materials.
Boott, Charlotte E; Nazemi, Ali; Manners, Ian
2015-11-16
The creation of synthetic 2D materials represents an attractive challenge that is ultimately driven by their prospective uses in, for example, electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration. This Review illustrates some recent advances in this diverse field with a focus on covalent and non-covalent 2D polymers and frameworks, and self-assembled 2D materials derived from nanoparticles, homopolymers, and block copolymers.
Estimating 2-D vector velocities using multidimensional spectrum analysis.
Oddershede, Niels; Løvstakken, Lasse; Torp, Hans; Jensen, Jørgen Arendt
2008-08-01
Wilson (1991) presented an ultrasonic wideband estimator for axial blood flow velocity estimation through the use of the 2-D Fourier transform. It was shown how a single velocity component was concentrated along a line in the 2-D Fourier space, where the slope was given by the axial velocity. Later, it was shown that this approach could also be used for finding the lateral velocity component by also including a lateral sampling. A single velocity component would then be concentrated along a plane in the 3-D Fourier space, tilted according to the 2 velocity components. This paper presents 2 new velocity estimators for finding both the axial and lateral velocity components. The estimators essentially search for the plane in the 3- D Fourier space, where the integrated power spectrum is largest. The first uses the 3-D Fourier transform to find the power spectrum, while the second uses a minimum variance approach. Based on this plane, the axial and lateral velocity components are estimated. Several phantom measurements, for flow-to-depth angles of 60, 75, and 90 degrees, were performed. Multiple parallel lines were beamformed simultaneously, and 2 different receive apodization schemes were tried. The 2 estimators were then applied to the data. The axial velocity component was estimated with an average standard deviation below 2.8% of the peak velocity, while the average standard deviation of the lateral velocity estimates was between 2.0% and 16.4%. The 2 estimators were also tested on in vivo data from a transverse scan of the common carotid artery, showing the potential of the vector velocity estimation method under in vivo conditions. PMID:18986918
2D Quantum Transport Modeling in Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, Bryan
2001-01-01
With the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density- gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions, oxide tunneling and phase-breaking scattering are treated on equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. Quantum simulations are focused on MIT 25, 50 and 90 nm "well- tempered" MOSFETs and compared to classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. These results are quantitatively consistent with I D Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and sub-threshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.
A Geometric Boolean Library for 2D Objects
2006-01-05
The 2D Boolean Library is a collection of C++ classes -- which primarily represent 2D geometric data and relationships, and routines -- which contain algorithms for 2D geometric Boolean operations and utility functions. Classes are provided for 2D points, lines, arcs, edgeuses, loops, surfaces and mask sets. Routines are provided that incorporate the Boolean operations Union(OR), XOR, Intersection and Difference. Various analytical geometry routines and routines for importing and exporting the data in various filemore » formats, are also provided in the library.« less
Klassifikation von Standardebenen in der 2D-Echokardiographie mittels 2D-3D-Bildregistrierung
NASA Astrophysics Data System (ADS)
Bergmeir, Christoph; Subramanian, Navneeth
Zum Zweck der Entwicklung eines Systems, das einen unerfahrenen Anwender von Ultraschall (US) zur Aufnahme relevanter anatomischer Strukturen leitet, untersuchen wir die Machbarkeit von 2D-US zu 3D-CT Registrierung. Wir verwenden US-Aufnahmen von Standardebenen des Herzens, welche zu einem 3D-CT-Modell registriert werden. Unser Algorithmus unterzieht sowohl die US-Bilder als auch den CT-Datensatz Vorverarbeitungsschritten, welche die Daten durch Segmentierung auf wesentliche Informationen in Form von Labein für Muskel und Blut reduzieren. Anschließend werden diese Label zur Registrierung mittels der Match-Cardinality-Metrik genutzt. Durch mehrmaliges Registrieren mit verschiedenen Initialisierungen ermitteln wir die im US-Bild sichtbare Standardebene. Wir evaluierten die Methode auf sieben US-Bildern von Standardebenen. Fünf davon wurden korrekt zugeordnet.
Epitaxial 2D SnSe2/ 2D WSe2 van der Waals Heterostructures.
Aretouli, Kleopatra Emmanouil; Tsoutsou, Dimitra; Tsipas, Polychronis; Marquez-Velasco, Jose; Aminalragia Giamini, Sigiava; Kelaidis, Nicolaos; Psycharis, Vassilis; Dimoulas, Athanasios
2016-09-01
van der Waals heterostructures of 2D semiconductor materials can be used to realize a number of (opto)electronic devices including tunneling field effect devices (TFETs). It is shown in this work that high quality SnSe2/WSe2 vdW heterostructure can be grown by molecular beam epitaxy on AlN(0001)/Si(111) substrates using a Bi2Se3 buffer layer. A valence band offset of 0.8 eV matches the energy gap of SnSe2 in such a way that the VB edge of WSe2 and the CB edge of SnSe2 are lined up, making this materials combination suitable for (nearly) broken gap TFETs. PMID:27537619
CVMAC 2D Program: A method of converting 3D to 2D
Lown, J.
1990-06-20
This paper presents the user with a method of converting a three- dimensional wire frame model into a technical illustration, detail, or assembly drawing. By using the 2D Program, entities can be mapped from three-dimensional model space into two-dimensional model space, as if they are being traced. Selected entities to be mapped can include circles, arcs, lines, and points. This program prompts the user to digitize the view to be mapped, specify the layers in which the new two-dimensional entities will reside, and select the entities, either by digitizing or windowing. The new two-dimensional entities are displayed in a small view which the program creates in the lower left corner of the drawing. 9 figs.
2D Four-Channel Perfect Reconstruction Filter Bank Realized with the 2D Lattice Filter Structure
NASA Astrophysics Data System (ADS)
Sezen, S.; Ertüzün, A.
2006-12-01
A novel orthogonal 2D lattice structure is incorporated into the design of a nonseparable 2D four-channel perfect reconstruction filter bank. The proposed filter bank is obtained by using the polyphase decomposition technique which requires the design of an orthogonal 2D lattice filter. Due to constraint of perfect reconstruction, each stage of this lattice filter bank is simply parameterized by two coefficients. The perfect reconstruction property is satisfied regardless of the actual values of these parameters and of the number of the lattice stages. It is also shown that a separable 2D four-channel perfect reconstruction lattice filter bank can be constructed from the 1D lattice filter and that this is a special case of the proposed 2D lattice filter bank under certain conditions. The perfect reconstruction property of the proposed 2D lattice filter approach is verified by computer simulations.
NASA Astrophysics Data System (ADS)
Dressing, Courtney D.; Charbonneau, David
2015-07-01
We present an improved estimate of the occurrence rate of small planets orbiting small stars by searching the full four-year Kepler data set for transiting planets using our own planet detection pipeline and conducting transit injection and recovery simulations to empirically measure the search completeness of our pipeline. We identified 156 planet candidates, including one object that was not previously identified as a Kepler Object of Interest. We inspected all publicly available follow-up images, observing notes, and centroid analyses, and corrected for the likelihood of false positives. We evaluated the sensitivity of our detection pipeline on a star-by-star basis by injecting 2000 transit signals into the light curve of each target star. For periods shorter than 50 days, we find {0.56}-0.05+0.06 Earth-size planets (1‑1.5 R⊕) and {0.46}-0.05+0.07 super-Earths (1.5‑2 R⊕) per M dwarf. In total, we estimate a cumulative planet occurrence rate of 2.5 ± 0.2 planets per M dwarf with radii 1‑4 R⊕ and periods shorter than 200 days. Within a conservatively defined habitable zone (HZ) based on the moist greenhouse inner limit and maximum greenhouse outer limit, we estimate an occurrence rate of {0.16}-0.07+0.17 Earth-size planets and {0.12}-0.05+0.10 super-Earths per M dwarf HZ. Adopting the broader insolation boundaries of the recent Venus and early Mars limits yields a higher estimate of {0.24}-0.08+0.18 Earth-size planets and {0.21}-0.06+0.11 super-Earths per M dwarf HZ. This suggests that the nearest potentially habitable non-transiting and transiting Earth-size planets are 2.6 ± 0.4 pc and {10.6}-1.8+1.6 pc away, respectively. If we include super-Earths, these distances diminish to 2.1 ± 0.2 pc and {8.6}-0.8+0.7 pc.
EFFECTS OF SMOKING ON D2/D3 STRIATAL RECEPTOR AVAILABILITY IN ALCOHOLICS AND SOCIAL DRINKERS
Albrecht, Daniel S.; Kareken, David A.; Yoder, Karmen K.
2013-01-01
Objective Studies have reported lower striatal D2/D3 receptor availability in both alcoholics and cigarette smokers relative to healthy controls. These substances are commonly co-abused, yet the relationship between comorbid alcohol/tobacco abuse and striatal D2/D3 receptor availability has not been examined. We sought to determine the degree to which dual abuse of alcohol and tobacco is associated with lower D2/D3 receptor availability. Method Eighty-one subjects (34 nontreatment-seeking alcoholic smokers [NTS-S], 21 social-drinking smokers [SD-S], and 26 social-drinking non-smokers [SD-NS]) received baseline [11C]raclopride scans. D2/D3 binding potential (BPND ≡ Bavail/KD) was estimated for ten anatomically defined striatal regions of interest (ROIs). Results Significant group effects were detected in bilateral pre-commissural dorsal putamen, bilateral pre-commissural dorsal caudate; and bilateral post-commissural dorsal putamen. Post-hoc testing revealed that, regardless of drinking status, smokers had lower D2/D3 receptor availability than non-smoking controls. Conclusions Chronic tobacco smokers have lower striatal D2/D3 receptor availability than non-smokers, independent of alcohol use. Additional studies are needed to identify the mechanisms by which chronic tobacco smoking is associated with striatal dopamine receptor availability. PMID:23649848
Optical Stark effect in 2D semiconductors
NASA Astrophysics Data System (ADS)
Sie, Edbert J.; McIver, James W.; Lee, Yi-Hsien; Fu, Liang; Kong, Jing; Gedik, Nuh
2016-05-01
Semiconductors that are atomically thin can exhibit novel optical properties beyond those encountered in the bulk compounds. Monolayer transition-metal dichalcogenides (TMDs) are leading examples of such semiconductors that possess remarkable optical properties. They obey unique selection rules where light with different circular polarization can be used for selective photoexcitation at two different valleys in the momentum space. These valleys constitute bandgaps that are normally locked in the same energy. Selectively varying their energies is of great interest for applications because it unlocks the potential to control valley degree of freedom, and offers a new promising way to carry information in next-generation valleytronics. In this proceeding paper, we show that the energy gaps at the two valleys can be shifted relative to each other by means of the optical Stark effect in a controllable valley-selective manner. We discuss the physics of the optical Stark effect, and we describe the mechanism that leads to its valleyselectivity in monolayer TMD tungsten disulfide (WS2).
Functional characterization of CYP2D6 enhancer polymorphisms
Wang, Danxin; Papp, Audrey C.; Sun, Xiaochun
2015-01-01
CYP2D6 metabolizes nearly 25% of clinically used drugs. Genetic polymorphisms cause large inter-individual variability in CYP2D6 enzyme activity and are currently used as biomarker to predict CYP2D6 metabolizer phenotype. Previously, we had identified a region 115 kb downstream of CYP2D6 as enhancer for CYP2D6, containing two completely linked single nucleotide polymorphisms (SNPs), rs133333 and rs5758550, associated with enhanced transcription. However, the enhancer effect on CYP2D6 expression, and the causative variant, remained to be ascertained. To characterize the CYP2D6 enhancer element, we applied chromatin conformation capture combined with the next-generation sequencing (4C assays) and chromatin immunoprecipitation with P300 antibody, in HepG2 and human primary culture hepatocytes. The results confirmed the role of the previously identified enhancer region in CYP2D6 expression, expanding the number of candidate variants to three highly linked SNPs (rs133333, rs5758550 and rs4822082). Among these, only rs5758550 demonstrated regulating enhancer activity in a reporter gene assay. Use of clustered regularly interspaced short palindromic repeats mediated genome editing in HepG2 cells targeting suspected enhancer regions decreased CYP2D6 mRNA expression by 70%, only upon deletion of the rs5758550 region. These results demonstrate robust effects of both the enhancer element and SNP rs5758550 on CYP2D6 expression, supporting consideration of rs5758550 for CYP2D6 genotyping panels to yield more accurate phenotype prediction. PMID:25381333
Mesophases in nearly 2D room-temperature ionic liquids.
Manini, N; Cesaratto, M; Del Pópolo, M G; Ballone, P
2009-11-26
Computer simulations of (i) a [C(12)mim][Tf(2)N] film of nanometric thickness squeezed at kbar pressure by a piecewise parabolic confining potential reveal a mesoscopic in-plane density and composition modulation reminiscent of mesophases seen in 3D samples of the same room-temperature ionic liquid (RTIL). Near 2D confinement, enforced by a high normal load, as well as relatively long aliphatic chains are strictly required for the mesophase formation, as confirmed by computations for two related systems made of (ii) the same [C(12)mim][Tf(2)N] adsorbed at a neutral solid surface and (iii) a shorter-chain RTIL ([C(4)mim][Tf(2)N]) trapped in the potential well of part i. No in-plane modulation is seen for ii and iii. In case ii, the optimal arrangement of charge and neutral tails is achieved by layering parallel to the surface, while, in case iii, weaker dispersion and packing interactions are unable to bring aliphatic tails together into mesoscopic islands, against overwhelming entropy and Coulomb forces. The onset of in-plane mesophases could greatly affect the properties of long-chain RTILs used as lubricants. PMID:19886615
NASA Astrophysics Data System (ADS)
Chae, Dongho; Constantin, Peter; Wu, Jiahong
2014-09-01
We give an example of a well posed, finite energy, 2D incompressible active scalar equation with the same scaling as the surface quasi-geostrophic equation and prove that it can produce finite time singularities. In spite of its simplicity, this seems to be the first such example. Further, we construct explicit solutions of the 2D Boussinesq equations whose gradients grow exponentially in time for all time. In addition, we introduce a variant of the 2D Boussinesq equations which is perhaps a more faithful companion of the 3D axisymmetric Euler equations than the usual 2D Boussinesq equations.
Adaptation algorithms for 2-D feedforward neural networks.
Kaczorek, T
1995-01-01
The generalized weight adaptation algorithms presented by J.G. Kuschewski et al. (1993) and by S.H. Zak and H.J. Sira-Ramirez (1990) are extended for 2-D madaline and 2-D two-layer feedforward neural nets (FNNs).
Integrating Mobile Multimedia into Textbooks: 2D Barcodes
ERIC Educational Resources Information Center
Uluyol, Celebi; Agca, R. Kagan
2012-01-01
The major goal of this study was to empirically compare text-plus-mobile phone learning using an integrated 2D barcode tag in a printed text with three other conditions described in multimedia learning theory. The method examined in the study involved modifications of the instructional material such that: a 2D barcode was used near the text, the…
Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes.
Byun, Jinwoo; Cho, Himchan; Wolf, Christoph; Jang, Mi; Sadhanala, Aditya; Friend, Richard H; Yang, Hoichang; Lee, Tae-Woo
2016-09-01
Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A(-1) ) are demonstrated by mixing a 3D-structured perovskite material (methyl ammonium lead bromide) and a 2D-structured perovskite material (phenylethyl ammonium lead bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, and reduced trap density. PMID:27334788
CYP2D6: novel genomic structures and alleles
Kramer, Whitney E.; Walker, Denise L.; O’Kane, Dennis J.; Mrazek, David A.; Fisher, Pamela K.; Dukek, Brian A.; Bruflat, Jamie K.; Black, John L.
2010-01-01
Objective CYP2D6 is a polymorphic gene. It has been observed to be deleted, to be duplicated and to undergo recombination events involving the CYP2D7 pseudogene and surrounding sequences. The objective of this study was to discover the genomic structure of CYP2D6 recombinants that interfere with clinical genotyping platforms that are available today. Methods Clinical samples containing rare homozygous CYP2D6 alleles, ambiguous readouts, and those with duplication signals and two different alleles were analyzed by long-range PCR amplification of individual genes, PCR fragment analysis, allele-specific primer extension assay, and DNA sequencing to characterize alleles and genomic structure. Results Novel alleles, genomic structures, and the DNA sequence of these structures are described. Interestingly, in 49 of 50 DNA samples that had CYP2D6 gene duplications or multiplications where two alleles were detected, the chromosome containing the duplication or multiplication had identical tandem alleles. Conclusion Several new CYP2D6 alleles and genomic structures are described which will be useful for CYP2D6 genotyping. The findings suggest that the recombination events responsible for CYP2D6 duplications and multiplications are because of mechanisms other than interchromosomal crossover during meiosis. PMID:19741566
Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes.
Byun, Jinwoo; Cho, Himchan; Wolf, Christoph; Jang, Mi; Sadhanala, Aditya; Friend, Richard H; Yang, Hoichang; Lee, Tae-Woo
2016-09-01
Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A(-1) ) are demonstrated by mixing a 3D-structured perovskite material (methyl ammonium lead bromide) and a 2D-structured perovskite material (phenylethyl ammonium lead bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, and reduced trap density.
2D materials and van der Waals heterostructures.
Novoselov, K S; Mishchenko, A; Carvalho, A; Castro Neto, A H
2016-07-29
The physics of two-dimensional (2D) materials and heterostructures based on such crystals has been developing extremely fast. With these new materials, truly 2D physics has begun to appear (for instance, the absence of long-range order, 2D excitons, commensurate-incommensurate transition, etc.). Novel heterostructure devices--such as tunneling transistors, resonant tunneling diodes, and light-emitting diodes--are also starting to emerge. Composed from individual 2D crystals, such devices use the properties of those materials to create functionalities that are not accessible in other heterostructures. Here we review the properties of novel 2D crystals and examine how their properties are used in new heterostructure devices.
Estrogen-Induced Cholestasis Leads to Repressed CYP2D6 Expression in CYP2D6-Humanized Mice
Pan, Xian
2015-01-01
Cholestasis activates bile acid receptor farnesoid X receptor (FXR) and subsequently enhances hepatic expression of small heterodimer partner (SHP). We previously demonstrated that SHP represses the transactivation of cytochrome P450 2D6 (CYP2D6) promoter by hepatocyte nuclear factor (HNF) 4α. In this study, we investigated the effects of estrogen-induced cholestasis on CYP2D6 expression. Estrogen-induced cholestasis occurs in subjects receiving estrogen for contraception or hormone replacement, or in susceptible women during pregnancy. In CYP2D6-humanized transgenic (Tg-CYP2D6) mice, cholestasis triggered by administration of 17α-ethinylestradiol (EE2) at a high dose led to 2- to 3-fold decreases in CYP2D6 expression. This was accompanied by increased hepatic SHP expression and subsequent decreases in the recruitment of HNF4α to CYP2D6 promoter. Interestingly, estrogen-induced cholestasis also led to increased recruitment of estrogen receptor (ER) α, but not that of FXR, to Shp promoter, suggesting a predominant role of ERα in transcriptional regulation of SHP in estrogen-induced cholestasis. EE2 at a low dose (that does not cause cholestasis) also increased SHP (by ∼50%) and decreased CYP2D6 expression (by 1.5-fold) in Tg-CYP2D6 mice, the magnitude of differences being much smaller than that shown in EE2-induced cholestasis. Taken together, our data indicate that EE2-induced cholestasis increases SHP and represses CYP2D6 expression in Tg-CYP2D6 mice in part through ERα transactivation of Shp promoter. PMID:25943116
Dual-mode operation of 2D material-base hot electron transistors
Lan, Yann-Wen; Torres, Jr., Carlos M.; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R.; Lerner, Mitchell B.; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L.
2016-01-01
Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications. PMID:27581550
Dual-mode operation of 2D material-base hot electron transistors
NASA Astrophysics Data System (ADS)
Lan, Yann-Wen; Torres, Carlos M., Jr.; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R.; Lerner, Mitchell B.; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L.
2016-09-01
Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.
Dual-mode operation of 2D material-base hot electron transistors.
Lan, Yann-Wen; Torres, Carlos M; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R; Lerner, Mitchell B; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L
2016-01-01
Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications. PMID:27581550
Dual-mode operation of 2D material-base hot electron transistors.
Lan, Yann-Wen; Torres, Carlos M; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R; Lerner, Mitchell B; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L
2016-09-01
Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.
Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng
2016-08-01
Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples.
The Accuracy of Webcams in 2D Motion Analysis: Sources of Error and Their Control
ERIC Educational Resources Information Center
Page, A.; Moreno, R.; Candelas, P.; Belmar, F.
2008-01-01
In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented.…
Practical Algorithm For Computing The 2-D Arithmetic Fourier Transform
NASA Astrophysics Data System (ADS)
Reed, Irving S.; Choi, Y. Y.; Yu, Xiaoli
1989-05-01
Recently, Tufts and Sadasiv [10] exposed a method for computing the coefficients of a Fourier series of a periodic function using the Mobius inversion of series. They called this method of analysis the Arithmetic Fourier Transform(AFT). The advantage of the AFT over the FN 1' is that this method of Fourier analysis needs only addition operations except for multiplications by scale factors at one stage of the computation. The disadvantage of the AFT as they expressed it originally is that it could be used effectively only to compute finite Fourier coefficients of a real even function. To remedy this the AFT developed in [10] is extended in [11] to compute the Fourier coefficients of both the even and odd components of a periodic function. In this paper, the improved AFT [11] is extended to a two-dimensional(2-D) Arithmetic Fourier Transform for calculating the Fourier Transform of two-dimensional discrete signals. This new algorithm is based on both the number-theoretic method of Mobius inversion of double series and the complex conjugate property of Fourier coefficients. The advantage of this algorithm over the conventional 2-D FFT is that the corner-turning problem needed in a conventional 2-D Discrete Fourier Transform(DFT) can be avoided. Therefore, this new 2-D algorithm is readily suitable for VLSI implementation as a parallel architecture. Comparing the operations of 2-D AFT of a MxM 2-D data array with the conventional 2-D FFT, the number of multiplications is significantly reduced from (2log2M)M2 to (9/4)M2. Hence, this new algorithm is faster than the FFT algorithm. Finally, two simulation results of this new 2-D AFT algorithm for 2-D artificial and real images are given in this paper.
Quantum Simulation with 2D Arrays of Trapped Ions
NASA Astrophysics Data System (ADS)
Richerme, Philip
2016-05-01
The computational difficulty of solving fully quantum many-body spin problems is a significant obstacle to understanding the behavior of strongly correlated quantum matter. This work proposes the design and construction of a 2D quantum spin simulator to investigate the physics of frustrated materials, highly entangled states, mechanisms potentially underpinning high-temperature superconductivity, and other topics inaccessible to current 1D systems. The effective quantum spins will be encoded within the well-isolated electronic levels of trapped ions, confined in a two-dimensional planar geometry, and made to interact using phonon-mediated optical dipole forces. The system will be scalable to 100+ quantum particles, far beyond the realm of classical intractability, while maintaining individual-ion control, long quantum coherence times, and site-resolved projective spin measurements. Once constructed, the two-dimensional quantum simulator will implement a broad range of spin models on a variety of reconfigurable lattices and characterize their behavior through measurements of spin-spin correlations and entanglement. This versatile tool will serve as an important experimental resource for exploring difficult quantum many-body problems in a regime where classical methods fail.
2-D Inhomogeneous Modeling of the Solar CO Bands
NASA Astrophysics Data System (ADS)
Ayres, T. R.
1996-05-01
The recent discovery of off-limb emissions in the mid-IR ( ~ 5 mu m) vibration-rotation bands of solar carbon monoxide (CO) has sparked new interest in the formation of the molecular lines, and their ability to diagnose thermal conditions at high altitudes. The off-limb extensions of the strong CO lines indicate the penetration of cool material (T ~ 3500 K) several hundred kilometers into the otherwise hot (T ~ 6000 K) chromosphere. The origin of the cool gas, and its role in the thermal energy balance, remain controversial. The interpretation of the CO observations must rely heavily upon numerical modeling, in particular highly-inhomogeneous thermal structures arrayed in a 2-D scheme that can properly treat the geometry of the grazing rays at the solar limb. The radiation transport, itself, is especially simple for the CO off-limb emissions, because the fundamental bands form quite close to LTE (high collision rates; low spontaneous decay rates) and the background continuum is purely thermal as well (f--f transitions in H(-) and H). Thus, the geometrical aspects of the problem can be treated in considerably more detail than would be practical for typical NLTE scattering lines. I describe the recent modeling efforts, and the diagnostic potential of the CO bands for future observational studies of inhomogeneous surface structure on the Sun, and on other stars of late spectral type. This work was supported by NSF grant AST-9218063 to the University of Colorado.
An Investigation of 2D Electrostatic Dust Levitation about Bennu
NASA Astrophysics Data System (ADS)
Hartzell, Christine; Zimmerman, Michael
2015-11-01
Electrostatic dust levitation has been hypothesized to occur near the surface of asteroids, due to the interaction of the solar wind plasma and UV radiation with the asteroids’ surfaces and their near-zero surficial gravity. Dust levitation could provide a mechanism to move regolith across the surface of an asteroid. Our preliminary investigations have identified grains sizes and the altitudes at which grains may levitate considering a semi-analytical 1D plasma model. However, our initial semi-analytical plasma model was not well-suited to the complex terminator region, where the surface transitions between positive (dominated by photoemission) and negative (in the plasma wake) potentials. In this analysis, we use a new 2D treecode-based plasma simulation to more accurately model the plasma environment about a simplified circular cross-section of the asteroid Bennu. We investigate the altitudes and grain sizes where electrostatic levitation could occur at Bennu. The improved plasma model will allow more accurate predictions of dust levitation and deposition, particularly in the terminator and wake regions that could not be characterized be earlier plasma models.
2D Fluidization of Nanomaterials by Biomimetic Membranes
NASA Astrophysics Data System (ADS)
Kelly, Kathleen; Forstner, Martin
2012-02-01
The last decade has seen much progress in the synthesis and manufacturing of a large variety of nanometer sized particles of different materials, geometries and properties. If they can be assembled into larger structures, these manmade nano-objects are posed to be the ``atoms'' and ``molecules'' of new materials. In order to facilitate their dynamic rearrangements we have developed a method that uses material specific binding peptides to anchor nano-objects to lipids in supported bilayers (SLB). In this study we use single walled carbon nanotubes (CNT) with a mean length of 1 micrometer as model of a potential nano-building block. By fluorescently labeling CNTs we are able to use video-microscopy to investigate the dynamic behavior of membrane anchored CNTs. We show that the 2D fluidity of the lipid membrane can be successfully templated on the CNTs and that they stay laterally mobile while being confined to a plane. Furthermore, the dependence of CNT mobility on specific binding stoichiometries is discussed.
Chemically engineered graphene-based 2D organic molecular magnet.
Hong, Jeongmin; Bekyarova, Elena; de Heer, Walt A; Haddon, Robert C; Khizroev, Sakhrat
2013-11-26
Carbon-based magnetic materials and structures of mesoscopic dimensions may offer unique opportunities for future nanomagnetoelectronic/spintronic devices. To achieve their potential, carbon nanosystems must have controllable magnetic properties. We demonstrate that nitrophenyl functionalized graphene can act as a room-temperature 2D magnet. We report a comprehensive study of low-temperature magnetotransport, vibrating sample magnetometry (VSM), and superconducting quantum interference (SQUID) measurements before and after radical functionalization. Following nitrophenyl (NP) functionalization, epitaxially grown graphene systems can become organic molecular magnets with ferromagnetic and antiferromagnetic ordering that persists at temperatures above 400 K. The field-dependent, surface magnetoelectric properties were studied using scanning probe microscopy (SPM) techniques. The results indicate that the NP-functionalization orientation and degree of coverage directly affect the magnetic properties of the graphene surface. In addition, graphene-based organic magnetic nanostructures were found to demonstrate a pronounced magneto-optical Kerr effect (MOKE). The results were consistent across different characterization techniques and indicate room-temperature magnetic ordering along preferred graphene orientations in the NP-functionalized samples. Chemically isolated graphene nanoribbons (CINs) were observed along the preferred functionality directions. These results pave the way for future magnetoelectronic/spintronic applications based on promising concepts such as current-induced magnetization switching, magnetoelectricity, half-metallicity, and quantum tunneling of magnetization.
Technology Transfer Automated Retrieval System (TEKTRAN)
Pre-ruminant Holstein bull calves were fed two diets of pasteurized whole milk (PWM) in amounts that either limited intake or that maximized intake according to common commercial practice. Diets then were either supplemented or not supplemented with a full complement of vitamins and trace minerals ...
Technology Transfer Automated Retrieval System (TEKTRAN)
Mountain Gem Russet is a medium to late maturing variety with both high early and full season yields of oblong-long, medium-russeted tubers having higher protein content than those of standard potato varieties. Mountain Gem Russet has greater resistance to tuber late blight, tuber malformations and ...
Fábri, Csaba; Császár, Attila G; Czakó, Gábor
2013-08-15
Variational rotational-vibrational quantum chemical computations are performed for the F(-)-CH4 and F(-)-CH2D2 anion complexes using several reduced-dimensional models in a curvilinear polyspherical coordinate system and utilizing an accurate ab initio potential energy surface (PES). The implementation of the models is made practical by using the general rovibrational code GENIUSH, which constructs the complicated form of the exact rovibrational kinetic energy operator in reduced and full dimensions in any user-specified coordinates and body-fixed frames. A one-dimensional CF stretch, 1D(RCF), a two-dimensional intermolecular bend, 2D(θ,φ), and a three-dimensional intermolecular, 3D(RCF,θ,φ), rigid methane model provide vibrational energies for the low-frequency, large-amplitude modes in good agreement with full-dimensional MCTDH results for F(-)-CH4. The 2D(θ,φ) and 3D(RCF,θ,φ) four-well computations, describing equally the four possible CH-F(-) bonds, show that the ground-state tunneling splitting is less than 0.01 cm(-1). For the hydrogen-bonded CH stretching fundamental a local-mode model is found to have almost spectroscopic accuracy, whereas a harmonic frequency analysis performs poorly. The 2D(θ,φ) and 3D(RCF,θ,φ) rotational-vibrational computations on the Td-symmetric four-well PES reveal that in most cases F(-)-CH4 behaves as a semirigid C3v symmetric top. For the degenerate intermolecular bending vibrational states substantial splittings of the rigid rotor levels are observed. For F(-)-CH2D2 the rotational levels guide the assignment of the vibrational states to either F(-)-H or F(-)-D connectivity. PMID:23402210
2D electron cyclotron emission imaging at ASDEX Upgrade (invited)
Classen, I. G. J.; Boom, J. E.; Vries, P. C. de; Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A.; Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr.; Donne, A. J. H.; Jaspers, R. J. E.; Park, H. K.; Munsat, T.
2010-10-15
The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.
Comparison of 2D and 3D gamma analyses
Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F.; Bosca, Ryan; O’Daniel, Jennifer
2014-02-15
Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must
Recent advances in 2D materials for photocatalysis.
Luo, Bin; Liu, Gang; Wang, Lianzhou
2016-04-01
Two-dimensional (2D) materials have attracted increasing attention for photocatalytic applications because of their unique thickness dependent physical and chemical properties. This review gives a brief overview of the recent developments concerning the chemical synthesis and structural design of 2D materials at the nanoscale and their applications in photocatalytic areas. In particular, recent progress on the emerging strategies for tailoring 2D material-based photocatalysts to improve their photo-activity including elemental doping, heterostructure design and functional architecture assembly is discussed.
Quasi 2D Materials: Raman Nanometrology and Thermal Management Applications
NASA Astrophysics Data System (ADS)
Shahil, Khan Mohammad Farhan
Quasi two-dimensional (2D) materials obtained by the "graphene-like" exfoliation attracted tremendous attention. Such materials revealed unique electronic, thermal and optical properties, which can be potentially used in electronics, thermal management and energy conversion. This dissertation research addresses two separate but synergetic problems: (i) preparation and optical characterization of quasi-2D films of the bismuth-telluride (Bi 2Te3) family of materials, which demonstrate both thermoelectric and topological insulator properties; and (ii) investigation of thermal properties of composite materials prepared with graphene and few-layer graphene (FLG). The first part of dissertation reports properties of the exfoliated few-quintuple layers of Bi2Te3, Bi2Se3 and Sb 2Te3. Both non-resonant and resonant Raman scattering spectra have been investigated. It was found that the crystal symmetry breaking in few-quintuple films results in appearance of A1u-symmetry Raman peaks, which are not active in the bulk crystals. The scattering spectra measured under the 633-nm wavelength excitation reveals a number of resonant features, which could be used for analysis of the electronic and phonon processes in these materials. The obtained results help to understand the physical mechanisms of Raman scattering in the few-quintuple-thick films and can be used for nanometrology of topological insulator films on various substrates. The second part of the dissertation is dedicated to investigation of properties of composite materials prepared with graphene and FLG. It was found that the optimized mixture of graphene and multilayer graphene---produced by the high-yield inexpensive liquid-phase-exfoliation technique---can lead to an extremely strong enhancement of the cross-plane thermal conductivity K of the composite. The "laser flash" measurements revealed a record-high enhancement of K by 2300 % in the graphene-based polymer at the filler loading fraction f =10 vol. %. It was
2D ESR image reconstruction from 1D projections using the modulated field gradient method
NASA Astrophysics Data System (ADS)
Páli, T.; Sass, L.; Horvat, L. I.; Ebert, B.
A method for the reconstruction of 2D ESR images from 1 D projections which is based on the modulated field gradient method has been explored. The 2D distribution of spin-labeled stearic acid in oriented and unoriented dimyristoyl phosphatidylcholine multilayers on a flat quartz support was determined. Such samples are potentially useful for the determination of lipid lateral diffusion in oriented multilayers by monitoring the spreading of a sharp concentration profile in one or two dimensions. The limitations of the method are discussed and the improvements which are needed for dynamic measurements are outlined.
Calculating tissue shear modulus and pressure by 2D Log-Elastographic methods
McLaughlin, Joyce R; Zhang, Ning; Manduca, Armando
2010-01-01
Shear modulus imaging, often called elastography, enables detection and characterization of tissue abnormalities. In this paper the data is two displacement components obtained from successive MR or ultrasound data sets acquired while the tissue is excited mechanically. A 2D plane strain elastic model is assumed to govern the 2D displacement, u. The shear modulus, μ, is unknown and whether or not the first Lamé parameter, λ, is known the pressure p = λ∇ · u which is present in the plane strain model cannot be measured and is unreliably computed from measured data and can be shown to be an order one quantity in the units kPa. So here we present a 2D Log-Elastographic inverse algorithm that: (1) simultaneously reconstructs the shear modulus, μ, and p, which together satisfy a first order partial differential equation system, with the goal of imaging μ; (2) controls potential exponential growth in the numerical error; and (3) reliably reconstructs the quantity p in the inverse algorithm as compared to the same quantity computed with a forward algorithm. This work generalizes the Log-Elastographic algorithm in [20] which uses one displacement component, is derived assuming the component satisfies the wave equation, and is tested on synthetic data computed with the wave equation model. The 2D Log-Elastographic algorithm is tested on 2D synthetic data and 2D in-vivo data from Mayo Clinic. We also exhibit examples to show that the 2D Log-Elastographic algorithm improves the quality of the recovered images as compared to the Log-Elastographic and Direct Inversion algorithms. PMID:21822349
Kaiglová, Jana; Langhammer, Jakub; Jiřinec, Petr; Janský, Bohumír; Chalupová, Dagmar
2015-03-01
This article used various hydrodynamic and sediment transport models to analyze the potential and the limits of different channel schematizations. The main aim was to select and evaluate the most suitable simulation method for fine-grained sediment remobilization assessment. Three types of channel schematization were selected to study the flow potential for remobilizing fine-grained sediment in artificially modified channels. Schematization with a 1D cross-sectional horizontal plan, a 1D+ approach, splitting the riverbed into different functional zones, and full 2D mesh, adopted in MIKE by the DHI modeling suite, was applied to the study. For the case study, a 55-km stretch of the Bílina River, in the Czech Republic, Central Europe, which has been heavily polluted by the chemical and coal mining industry since the mid-twentieth century, was selected. Long-term exposure to direct emissions of toxic pollutants including heavy metals and persistent organic pollutants (POPs) resulted in deposits of pollutants in fine-grained sediments in the riverbed. Simulations, based on three hydrodynamic model schematizations, proved that for events not exceeding the extent of the riverbed profile, the 1D schematization can provide comparable results to a 2D model. The 1D+ schematization can improve accuracy while keeping the benefits of high-speed simulation and low requirements of input DEM data, but the method's suitability is limited by the channel properties. PMID:25687259
Li, Jun E-mail: zhangdh@dicp.ac.cn; Chen, Jun; Zhao, Zhiqiang; Zhang, Dong H. E-mail: zhangdh@dicp.ac.cn; Xie, Daiqian; Guo, Hua
2015-05-28
We report a permutationally invariant global potential energy surface (PES) for the H + CH{sub 4} system based on ∼63 000 data points calculated at a high ab initio level (UCCSD(T)-F12a/AVTZ) using the recently proposed permutation invariant polynomial-neural network method. The small fitting error (5.1 meV) indicates a faithful representation of the ab initio points over a large configuration space. The rate coefficients calculated on the PES using tunneling corrected transition-state theory and quasi-classical trajectory are found to agree well with the available experimental and previous quantum dynamical results. The calculated total reaction probabilities (J{sub tot} = 0) including the abstraction and exchange channels using the new potential by a reduced dimensional quantum dynamic method are essentially the same as those on the Xu-Chen-Zhang PES [Chin. J. Chem. Phys. 27, 373 (2014)].
Boateng, Joshua; Diunase, Keshu Nso
2015-01-01
The increased incidence of bacterial resistance to antibiotics has generated renewed interest in "traditional" antimicrobials, such as honey. This paper reports on a study comparing physico-chemical, antioxidant and antibacterial characteristics (that potentially contribute in part, to the functional wound healing activity) of Cameroonian honeys with those of Manuka honey. Agar well diffusion was used to generate zones of inhibition against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus while broth dilutions were used to study the minimum inhibitory concentrations (MICs). Non-peroxide activity was investigated by catalase for hydrogen peroxide reduction. The Cameroonian honeys demonstrated functional properties similar to Manuka honey, with strong correlations between the antioxidant activity and total phenol content of each honey. They were also as effective as Manuka honey in reducing bacteria load with an MIC of 10% w/v against all three bacteria and exhibited non-peroxide antimicrobial activity. These Cameroon honeys have potential therapeutic activity and may contain compounds with activity against Gram positive and Gram negative bacteria. Antibacterial agents from such natural sources present a potential affordable treatment of wound infections caused by antibiotic resistant bacteria, which are a leading cause of amputations and deaths in many African countries. PMID:26364634
Boateng, Joshua; Diunase, Keshu Nso
2015-09-02
The increased incidence of bacterial resistance to antibiotics has generated renewed interest in "traditional" antimicrobials, such as honey. This paper reports on a study comparing physico-chemical, antioxidant and antibacterial characteristics (that potentially contribute in part, to the functional wound healing activity) of Cameroonian honeys with those of Manuka honey. Agar well diffusion was used to generate zones of inhibition against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus while broth dilutions were used to study the minimum inhibitory concentrations (MICs). Non-peroxide activity was investigated by catalase for hydrogen peroxide reduction. The Cameroonian honeys demonstrated functional properties similar to Manuka honey, with strong correlations between the antioxidant activity and total phenol content of each honey. They were also as effective as Manuka honey in reducing bacteria load with an MIC of 10% w/v against all three bacteria and exhibited non-peroxide antimicrobial activity. These Cameroon honeys have potential therapeutic activity and may contain compounds with activity against Gram positive and Gram negative bacteria. Antibacterial agents from such natural sources present a potential affordable treatment of wound infections caused by antibiotic resistant bacteria, which are a leading cause of amputations and deaths in many African countries.
NASA Astrophysics Data System (ADS)
Yoo, Ji Ho (Chris); Evans, Corey; Walker, Nick; Le Roy, Robert J.
2015-06-01
At last year's ISMS meeting, Zaleski et al. reported new broadband MW spectroscopy measurements of pure rotational transitions in the v=0-6 levels of the ^2Π1/2 ground electronic state of PbI. The analysis presented at that time was a conventional v-level by v-level `band-constant' analysis performed using the PGopher program. That level-by-level PGopher analysis yielded values of B_v, D_v and five spin-splitting parameters for each vibrational level of each isotopologue. Ignoring the spin-splitting information, the B_v and D_v values were used to generate a set of synthetic pure R(0) transitions for each level that were taken to represent the ``mechanical'' information about the molecule contained in these spectra. A standard direct-potential-fit (DPF) analysis was then used to fit these data to an ``Expanded Morse Oscillator'' (EMO) potential function form. The well-depth parameter D_e was fixed at the literature value, while values of the equilibrium distance r_e and three EMO exponent-coefficient expansion `potential shape' parameters are determined from the fits. The best fits to the data yield potentials whose fundamental vibrational spacings are in excellent agreement with experiment together with reliable predictions for the first five overtone energies. D.P. Zaleski, H. Köckert, S.L. Stephens, N. Walker, L.-M. Dickens, and C. Evans, paper RE08 at the 69th International Symposium on Molecular Spectroscopy, University of Illinois (2014). PGopher - a Program for Simulating Rotational Structure, C. M. Western, University of Bristol, http://pgopher.chm.bris.ac.uk DPotFit 2.0: A Computer Program for fitting Diatomic Molecule Spectra to Potential Energy Functions, R.J. Le Roy, J. Seto and Y. Huang, University of Waterloo Chemical Physics Research Report CP-667 (2013); see http://leroy.uwaterloo.ca/programs/. K. Ziebarth, R. Breidohr, O. Shestakov and E.H. Fink, Chem. Phys. Lett. 190, 271 (1992).
Gravitational Wave Signals from 2D and 3D Core Collapse Supernova Explosions
NASA Astrophysics Data System (ADS)
Yakunin, Konstantin; Mezzacappa, Anthony; Marronetti, Pedro; Bruenn, Stephen; Hix, W. Raphael; Lentz, Eric J.; Messer, O. E. Bronson; Harris, J. Austin; Endeve, Eirik; Blondin, John
2016-03-01
We study two- and three-dimensional (2D and 3D) core-collapse supernovae (CCSN) using our first-principles CCSN simulations performed with the neutrino hydrodynamics code CHIMERA. The following physics is included: Newtonian hydrodynamics with a nuclear equation of state capable of describing matter in both NSE and non-NSE, MGFLD neutrino transport with realistic neutrino interactions, an effective GR gravitational potential, and a nuclear reaction network. Both our 2D and 3D models achieve explosion, which in turn enables us to determine their complete gravitational wave signals. In this talk, we present them, and we analyze the similarities and differences between the 2D and 3D signals.
Spectroscopic investigation of the 3d 2D → nf 2F transitions in lithium
NASA Astrophysics Data System (ADS)
Shahzada, S.; Shah, M.; Haq, S. U.; Nawaz, M.; Ahmed, M.; Nadeem, Ali
2016-05-01
We report term energies and effective quantum numbers of the odd parity 3d 2D → nf 2F series of lithium using multi-step and multi-photon laser excitation schemes. The experiments were performed using three dye lasers simultaneously pumped by the second harmonic (532 nm) of a Q-switched Nd:YAG laser in conjunction with an atomic beam apparatus and thermionic diode ion detector. The first ionization potential of lithium has been determined as 43,487.13 ± 0.02 cm- 1 from the much extended 3d 2D → nf 2F (17 ≤ n ≤ 70) series. In addition, the oscillator strengths of the 3d 2D → nf 2F (15 ≤ n ≤ 48) transitions have been determined, showing a decreasing trend with the increase in principal quantum number n.
2D hexagonal quaternion Fourier transform in color image processing
NASA Astrophysics Data System (ADS)
Grigoryan, Artyom M.; Agaian, Sos S.
2016-05-01
In this paper, we present a novel concept of the quaternion discrete Fourier transform on the two-dimensional hexagonal lattice, which we call the two-dimensional hexagonal quaternion discrete Fourier transform (2-D HQDFT). The concept of the right-side 2D HQDFT is described and the left-side 2-D HQDFT is similarly considered. To calculate the transform, the image on the hexagonal lattice is described in the tensor representation when the image is presented by a set of 1-D signals, or splitting-signals which can be separately processed in the frequency domain. The 2-D HQDFT can be calculated by a set of 1-D quaternion discrete Fourier transforms (QDFT) of the splitting-signals.
Technical Review of the UNET2D Hydraulic Model
Perkins, William A.; Richmond, Marshall C.
2009-05-18
The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.
ORION96. 2-d Finite Element Code Postprocessor
Sanford, L.A.; Hallquist, J.O.
1992-02-02
ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
PiCode: A New Picture-Embedding 2D Barcode.
Chen, Changsheng; Huang, Wenjian; Zhou, Baojian; Liu, Chenchen; Mow, Wai Ho
2016-08-01
Nowadays, 2D barcodes have been widely used as an interface to connect potential customers and advertisement contents. However, the appearance of a conventional 2D barcode pattern is often too obtrusive for integrating into an aesthetically designed advertisement. Besides, no human readable information is provided before the barcode is successfully decoded. This paper proposes a new picture-embedding 2D barcode, called PiCode, which mitigates these two limitations by equipping a scannable 2D barcode with a picturesque appearance. PiCode is designed with careful considerations on both the perceptual quality of the embedded image and the decoding robustness of the encoded message. Comparisons with the existing beautified 2D barcodes show that PiCode achieves one of the best perceptual qualities for the embedded image, and maintains a better tradeoff between image quality and decoding robustness in various application conditions. PiCode has been implemented in the MATLAB on a PC and some key building blocks have also been ported to Android and iOS platforms. Its practicality for real-world applications has been successfully demonstrated. PMID:27249833
The infrared spectrum of the Ne-C2D2 complex.
Moazzen-Ahmadi, N; McKellar, A R W; Fernández, Berta; Farrelly, David
2015-11-28
Infrared spectra of Ne-C2D2 are observed in the region of the ν3 fundamental band (asymmetric C-D stretch, ≈2440 cm(-1)) using a tunable optical parametric oscillator to probe a pulsed supersonic slit jet expansion from a cooled nozzle. Like helium-acetylene, this system lies close to the free rotor limit, making analysis tricky because stronger transitions tend to pile up close to monomer (C2D2) rotation-vibration transitions. Assignments are aided by predicted rotational energies calculated from a published ab initio intermolecular potential energy surface. The analysis extends up to the j = 3←2 band, where j labels C2D2 rotation within the dimer, and is much more complete than the limited infrared assignments previously reported for Ne-C2H2 and Ne-C2HD. Two previous microwave transitions within the j = 1 state of Ne-C2D2 are reassigned. Coriolis model fits to the theoretical levels and to the spectrum are compared. Since the variations observed as a function of C2D2 vibrational excitation are comparable to those noted between theory and experiment, it is evident that more detailed testing of theory will require vibrational averaging over the acetylene intramolecular modes.
Simulation of Cardiac Arrhythmias Using a 2D Heterogeneous Whole Heart Model.
Balakrishnan, Minimol; Chakravarthy, V Srinivasa; Guhathakurta, Soma
2015-01-01
Simulation studies of cardiac arrhythmias at the whole heart level with electrocardiogram (ECG) gives an understanding of how the underlying cell and tissue level changes manifest as rhythm disturbances in the ECG. We present a 2D whole heart model (WHM2D) which can accommodate variations at the cellular level and can generate the ECG waveform. It is shown that, by varying cellular-level parameters like the gap junction conductance (GJC), excitability, action potential duration (APD) and frequency of oscillations of the auto-rhythmic cell in WHM2D a large variety of cardiac arrhythmias can be generated including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus pause, junctional rhythm, Wolf Parkinson White syndrome and all types of AV conduction blocks. WHM2D includes key components of the electrical conduction system of the heart like the SA (Sino atrial) node cells, fast conducting intranodal pathways, slow conducting atriovenctricular (AV) node, bundle of His cells, Purkinje network, atrial, and ventricular myocardial cells. SA nodal cells, AV nodal cells, bundle of His cells, and Purkinje cells are represented by the Fitzhugh-Nagumo (FN) model which is a reduced model of the Hodgkin-Huxley neuron model. The atrial and ventricular myocardial cells are modeled by the Aliev-Panfilov (AP) two-variable model proposed for cardiac excitation. WHM2D can prove to be a valuable clinical tool for understanding cardiac arrhythmias.
Simulation of Cardiac Arrhythmias Using a 2D Heterogeneous Whole Heart Model
Balakrishnan, Minimol; Chakravarthy, V. Srinivasa; Guhathakurta, Soma
2015-01-01
Simulation studies of cardiac arrhythmias at the whole heart level with electrocardiogram (ECG) gives an understanding of how the underlying cell and tissue level changes manifest as rhythm disturbances in the ECG. We present a 2D whole heart model (WHM2D) which can accommodate variations at the cellular level and can generate the ECG waveform. It is shown that, by varying cellular-level parameters like the gap junction conductance (GJC), excitability, action potential duration (APD) and frequency of oscillations of the auto-rhythmic cell in WHM2D a large variety of cardiac arrhythmias can be generated including sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus pause, junctional rhythm, Wolf Parkinson White syndrome and all types of AV conduction blocks. WHM2D includes key components of the electrical conduction system of the heart like the SA (Sino atrial) node cells, fast conducting intranodal pathways, slow conducting atriovenctricular (AV) node, bundle of His cells, Purkinje network, atrial, and ventricular myocardial cells. SA nodal cells, AV nodal cells, bundle of His cells, and Purkinje cells are represented by the Fitzhugh-Nagumo (FN) model which is a reduced model of the Hodgkin-Huxley neuron model. The atrial and ventricular myocardial cells are modeled by the Aliev-Panfilov (AP) two-variable model proposed for cardiac excitation. WHM2D can prove to be a valuable clinical tool for understanding cardiac arrhythmias. PMID:26733873
Construction of 2D atomic crystals on transition metal surfaces: graphene, silicene, and hafnene.
Pan, Yi; Zhang, Lizhi; Huang, Li; Li, Linfei; Meng, Lei; Gao, Min; Huan, Qing; Lin, Xiao; Wang, Yeliang; Du, Shixuan; Freund, Hans-Joachim; Gao, Hong-Jun
2014-06-12
The synthesis and structures of graphene on Ru(0001) and Pt(111), silicene on Ag(111) and Ir(111) and the honeycomb hafnium lattice on Ir(111) are reviewed. Epitaxy on a transition metal (TM) substrate is a pro-mising method to produce a variety of two dimensional (2D) atomic crystals which potentially can be used in next generation electronic devices. This method is particularly valuable in the case of producing 2D materials that do not exist in 3D forms, for instance, silicene. Based on the intensive investigations of epitaxial graphene on TM in recent years, it is known that the quality of graphene is affected by many factors, including the interaction between the 2D material overlayer and the substrate, the lattice mismatch, the nucleation density at the early stage of growth. It is found that these factors also apply to many other epitaxial 2D crystals on TM. The knowledge from the reviewed systems will shine light on the design and synthesis of new 2D crystals with novel properties.
Chmelík, M; Kukurová, I Just; Gruber, S; Krššák, M; Valkovič, L; Trattnig, S; Bogner, W
2013-05-01
A fully adiabatic phosphorus (31P) two-dimensional (2D) chemical shift spectroscopic imaging sequence with reduced chemical shift displacement error for 7 T, based on 1D-image-selected in vivo spectroscopy, combined with 2D-chemical shift spectroscopic imaging selection, was developed. Slice-selective excitation was achieved by a spatially selective broadband GOIA-W(16,4) inversion pulse with an interleaved subtraction scheme before nonselective adiabatic excitation, and followed by 2D phase encoding. The use of GOIA-W(16,4) pulses (bandwidth 4.3-21.6 kHz for 10-50 mm slices) reduced the chemical shift displacement error in the slice direction ∼1.5-7.7 fold, compared to conventional 2D-chemical shift spectroscopic imaging with Sinc3 selective pulses (2.8 kHz). This reduction was experimentally demonstrated with measurements of an MR spectroscopy localization phantom and with experimental evaluation of pulse profiles. In vivo experiments in clinically acceptable measurement times were demonstrated in the calf muscle (nominal voxel volume, 5.65 ml in 6 min 53 s), brain (10 ml, 6 min 32 s), and liver (8.33 ml, 8 min 14 s) of healthy volunteers at 7 T. High reproducibility was found in the calf muscle at 7 T. In combination with adiabatic excitation, this sequence is insensitive to the B1 inhomogeneities associated with surface coils. This sequence, which is termed GOIA-1D-ISIS/2D-CSI (goISICS), has the potential to be applied in both clinical research and in the clinical routine.
Phylogenetic tree construction based on 2D graphical representation
NASA Astrophysics Data System (ADS)
Liao, Bo; Shan, Xinzhou; Zhu, Wen; Li, Renfa
2006-04-01
A new approach based on the two-dimensional (2D) graphical representation of the whole genome sequence [Bo Liao, Chem. Phys. Lett., 401(2005) 196.] is proposed to analyze the phylogenetic relationships of genomes. The evolutionary distances are obtained through measuring the differences among the 2D curves. The fuzzy theory is used to construct phylogenetic tree. The phylogenetic relationships of H5N1 avian influenza virus illustrate the utility of our approach.
Generating a 2D Representation of a Complex Data Structure
NASA Technical Reports Server (NTRS)
James, Mark
2006-01-01
A computer program, designed to assist in the development and debugging of other software, generates a two-dimensional (2D) representation of a possibly complex n-dimensional (where n is an integer >2) data structure or abstract rank-n object in that other software. The nature of the 2D representation is such that it can be displayed on a non-graphical output device and distributed by non-graphical means.
Anisotropic 2D Materials for Tunable Hyperbolic Plasmonics.
Nemilentsau, Andrei; Low, Tony; Hanson, George
2016-02-12
Motivated by the recent emergence of a new class of anisotropic 2D materials, we examine their electromagnetic modes and demonstrate that a broad class of the materials can host highly directional hyperbolic plasmons. Their propagation direction can be manipulated on the spot by gate doping, enabling hyperbolic beam reflection, refraction, and bending. The realization of these natural 2D hyperbolic media opens up a new avenue in dynamic control of hyperbolic plasmons not possible in the 3D version.
A simultaneous 2D/3D autostereo workstation
NASA Astrophysics Data System (ADS)
Chau, Dennis; McGinnis, Bradley; Talandis, Jonas; Leigh, Jason; Peterka, Tom; Knoll, Aaron; Sumer, Aslihan; Papka, Michael; Jellinek, Julius
2012-03-01
We present a novel immersive workstation environment that scientists can use for 3D data exploration and as their everyday 2D computer monitor. Our implementation is based on an autostereoscopic dynamic parallax barrier 2D/3D display, interactive input devices, and a software infrastructure that allows client/server software modules to couple the workstation to scientists' visualization applications. This paper describes the hardware construction and calibration, software components, and a demonstration of our system in nanoscale materials science exploration.
QUENCH2D. Two-Dimensional IHCP Code
Osman, A.; Beck, J.V.
1995-01-01
QUENCH2D* is developed for the solution of general, non-linear, two-dimensional inverse heat transfer problems. This program provides estimates for the surface heat flux distribution and/or heat transfer coefficient as a function of time and space by using transient temperature measurements at appropriate interior points inside the quenched body. Two-dimensional planar and axisymmetric geometries such as turnbine disks and blades, clutch packs, and many other problems can be analyzed using QUENCH2D*.
A real-time multi-scale 2D Gaussian filter based on FPGA
NASA Astrophysics Data System (ADS)
Luo, Haibo; Gai, Xingqin; Chang, Zheng; Hui, Bin
2014-11-01
Multi-scale 2-D Gaussian filter has been widely used in feature extraction (e.g. SIFT, edge etc.), image segmentation, image enhancement, image noise removing, multi-scale shape description etc. However, their computational complexity remains an issue for real-time image processing systems. Aimed at this problem, we propose a framework of multi-scale 2-D Gaussian filter based on FPGA in this paper. Firstly, a full-hardware architecture based on parallel pipeline was designed to achieve high throughput rate. Secondly, in order to save some multiplier, the 2-D convolution is separated into two 1-D convolutions. Thirdly, a dedicate first in first out memory named as CAFIFO (Column Addressing FIFO) was designed to avoid the error propagating induced by spark on clock. Finally, a shared memory framework was designed to reduce memory costs. As a demonstration, we realized a 3 scales 2-D Gaussian filter on a single ALTERA Cyclone III FPGA chip. Experimental results show that, the proposed framework can computing a Multi-scales 2-D Gaussian filtering within one pixel clock period, is further suitable for real-time image processing. Moreover, the main principle can be popularized to the other operators based on convolution, such as Gabor filter, Sobel operator and so on.
Hua -Gen Yu; Han, Huixian; Guo, Hua
2016-03-29
Vibrational energy levels of the ammonium cation (NH4+) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4+ and ND4+ exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. As a result, the low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm–1.
Yu, Hua-Gen; Han, Huixian; Guo, Hua
2016-04-14
Vibrational energy levels of the ammonium cation (NH4(+)) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4(+) and ND4(+) exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. The low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm(-1).
Li, Guo-Rong; Xie, Chen-Chao; Shen, Zhu-Rui; Chang, Ze; Bu, Xian-He
2016-05-01
In this work, the construction of Co3O4 two dimensional (2D) nano-assemblies utilizing infinite coordination polymers (ICPs) as precursors was investigated, aiming at the morphology targeted fabrication and utilization of 2D materials. Based on the successful modulation of morphology, a rose-like Co based ICP precursor was obtained, which was further transformed into porous Co3O4 nanoflake assemblies with a well-preserved 2D morphology and a large surface area. The mechanism of the morphology modulation was illustrated by systematic investigation, which demonstrated the crucial role of a modulating agent in the formation of 2D nano-assemblies. In addition, the cobalt oxide 2D nano-assemblies are fabricated into a lithium anode combined with graphene, and the remarkable capacity and stability (900 mA h g(-1) after 50 cycles) of the resulting Co3O4/G nanocomposite indicates its potential in lithium battery applications. PMID:27064264
Li, Guo-Rong; Xie, Chen-Chao; Shen, Zhu-Rui; Chang, Ze; Bu, Xian-He
2016-05-01
In this work, the construction of Co3O4 two dimensional (2D) nano-assemblies utilizing infinite coordination polymers (ICPs) as precursors was investigated, aiming at the morphology targeted fabrication and utilization of 2D materials. Based on the successful modulation of morphology, a rose-like Co based ICP precursor was obtained, which was further transformed into porous Co3O4 nanoflake assemblies with a well-preserved 2D morphology and a large surface area. The mechanism of the morphology modulation was illustrated by systematic investigation, which demonstrated the crucial role of a modulating agent in the formation of 2D nano-assemblies. In addition, the cobalt oxide 2D nano-assemblies are fabricated into a lithium anode combined with graphene, and the remarkable capacity and stability (900 mA h g(-1) after 50 cycles) of the resulting Co3O4/G nanocomposite indicates its potential in lithium battery applications.
Ferriday, Danielle; Bosworth, Matthew L; Godinot, Nicolas; Martin, Nathalie; Forde, Ciarán G; Van Den Heuvel, Emmy; Appleton, Sarah L; Mercer Moss, Felix J; Rogers, Peter J; Brunstrom, Jeffrey M
2016-01-01
Laboratory studies have demonstrated that experimental manipulations of oral processing can have a marked effect on energy intake. Here, we explored whether variations in oral processing across a range of unmodified everyday meals could affect post-meal fullness and meal size. In Study 1, female participants (N = 12) attended the laboratory over 20 lunchtime sessions to consume a 400-kcal portion of a different commercially available pre-packaged meal. Prior to consumption, expected satiation was assessed. During each meal, oral processing was characterised using: (i) video-recordings of the mouth and (ii) real-time measures of plate weight. Hunger and fullness ratings were elicited pre- and post-consumption, and for a further three hours. Foods that were eaten slowly had higher expected satiation and delivered more satiation and satiety. Building on these findings, in Study 2 we selected two meals (identical energy density) from Study 1 that were equally liked but maximised differences in oral processing. On separate days, male and female participants (N = 24) consumed a 400-kcal portion of either the "fast" or "slow" meal followed by an ad libitum meal (either the same food or a dessert). When continuing with the same food, participants consumed less of the slow meal. Further, differences in food intake during the ad libitum meal were not compensated at a subsequent snacking opportunity an hour later. Together, these findings suggest that variations in oral processing across a range of unmodified everyday meals can affect fullness after consuming a fixed portion and can also impact meal size. Modifying food form to encourage increased oral processing (albeit to a lesser extent than in experimental manipulations) might represent a viable target for food manufacturers to help to nudge consumers to manage their weight. PMID:27213451
Ferriday, Danielle; Bosworth, Matthew L.; Godinot, Nicolas; Martin, Nathalie; Forde, Ciarán G.; Van Den Heuvel, Emmy; Appleton, Sarah L.; Mercer Moss, Felix J.; Rogers, Peter J.; Brunstrom, Jeffrey M.
2016-01-01
Laboratory studies have demonstrated that experimental manipulations of oral processing can have a marked effect on energy intake. Here, we explored whether variations in oral processing across a range of unmodified everyday meals could affect post-meal fullness and meal size. In Study 1, female participants (N = 12) attended the laboratory over 20 lunchtime sessions to consume a 400-kcal portion of a different commercially available pre-packaged meal. Prior to consumption, expected satiation was assessed. During each meal, oral processing was characterised using: (i) video-recordings of the mouth and (ii) real-time measures of plate weight. Hunger and fullness ratings were elicited pre- and post-consumption, and for a further three hours. Foods that were eaten slowly had higher expected satiation and delivered more satiation and satiety. Building on these findings, in Study 2 we selected two meals (identical energy density) from Study 1 that were equally liked but maximised differences in oral processing. On separate days, male and female participants (N = 24) consumed a 400-kcal portion of either the “fast” or “slow” meal followed by an ad libitum meal (either the same food or a dessert). When continuing with the same food, participants consumed less of the slow meal. Further, differences in food intake during the ad libitum meal were not compensated at a subsequent snacking opportunity an hour later. Together, these findings suggest that variations in oral processing across a range of unmodified everyday meals can affect fullness after consuming a fixed portion and can also impact meal size. Modifying food form to encourage increased oral processing (albeit to a lesser extent than in experimental manipulations) might represent a viable target for food manufacturers to help to nudge consumers to manage their weight. PMID:27213451
Assessment and improvement of the 2D/1D method stability in DeCART
Stimpson, S.; Young, M.; Collins, B.; Kelley, B.; Downar, T.
2013-07-01
As part of ongoing work with Consortium for Advanced Simulation of Light Water Reactors (CASL), the 2D/1D code, DeCART, has demonstrated some of the advantages of the 2D/1D method with respect to realistic, full-core analysis, particularly over explicit 3D transport methods, which generally have higher memory and computation requirements. The 2D/1D method performs 2D-radial transport sweeps coupled with ID-axial diffusion calculations to provide a full 3D simulation. DeCART employs the 2D method of characteristics for the radial sweeps and ID one-node nodal diffusion for the axial sweeps, coupling the two methods with transverse leakages to ensure a more consistent representation of the transport equation. It has been observed that refinement of the axial plane thickness leads to instabilities in the calculation scheme. This work assesses the sources of these instabilities and the approaches to improve them, especially with respect to negative scattering cross sections and the tightness of the 2D-radial/ID-axial coupling schemes. Fourier analyses show that the existing iteration scheme is not unconditionally stable, suggesting a tighter coupling scheme is required. For this reason 3D-CMFD has been implemented, among other developments, to ensure more stable calculation. A matrix of test cases has been used to assess the convergence, with the primary parameter being the axial plane thickness, which has been refined down to 1 cm. These cases demonstrate the issues observed and how the modification improve the stability. However, it is apparent that more work is necessary to ensure unconditional stability. (authors)
Yu, Dandan; Holm, Ruth; Goscinski, Mariusz Adam; Trope, Claes G; Nesland, Jahn M; Suo, Zhenhe
2016-01-01
Ovarian cancer is the most lethal gynecologic malignancy, in which cancer stem cells (CSC) have been reported to be the driving force of relapse and therapy-resistance. It is therefore important to explore CSC markers in ovarian cancer. This project aimed to explore the correlation between the expression of potential CSC maker Cacna2d1 and clinicopathological parameters in 238 epithelial ovarian cancer (EOC) samples. Immunohistochemically, positive Cacna2d1 expression was observed in 83.6% (199/238) of the EOC tumors, among which 107 tumors (44.9%) were highly positive and 92 (38.7%) tumors were weakly positive for the Cacna2d1 protein expression. Among the 158 serous carcinomas, the Cacna2d1 positivity was 148 (93.7%), in which 88 (55.7%) were highly positive, and 60 (38.0%) were weakly positive for the Cacna2d1 protein expression. Most strikingly, the Cacna2d1 was specifically expressed in the infiltration front areas of the EOC tumors. Statistical analyses showed that positive expression of Cacna2d1 was significantly associated with advanced FIGO stage (P<0.001), histological subtype (P=0.017) and tumor differentiation (P=0.015). Positive Cacna2d1 protein expression was significantly associated with poor overall survival (OS) and shorter progression free survival (PFS) in both total EOCs and serous carcinomas, although multivariate analyses did not reach statistical significance. In summary, our results suggest Cacna2d1 protein may play a crucial role in promoting aggressive EOC behavior and progression, and Cacna2d1 may serve as a novel predictive prognostic marker and a potential target for therapeutic intervention in EOCs. PMID:27725913
Zhu, Yi-Kang; Li, Chun-Bo; Jin, Jin; Wang, Ji-Jun; Lachmann, Bernd; Sariyska, Rayna; Montag, Christian
2014-06-01
Prenatal estrogen/testosterone exposure is known to be involved in early brain development. In this context, the ratio of the index finger to ring finger length (2D:4D) has been put forward as an indicator of the intrauterine sex hormonal level. A previous study by Collinson et al. (2010) examined 2D:4D ratios in Asian patients with schizophrenia and found an increased 2D:4D pattern in male patients compared to male healthy controls. In the current study, we tried to replicate the result of this study on the 2D:4D ratio in schizophrenia patients and controls in a Chinese sample. Moreover, we investigated the link between 2D:4D ratios and schizotypal personality traits in the participants of the study. No significant difference between cases and controls in 2D:4D ratios for both hands could be observed. However, a positive association between right 2D:4D ratio and schizotypal personality traits was found in healthy controls (both in the male and female subsamples) suggesting that a high 2D:4D ratio could represent a vulnerability factor for schizophrenia in healthy males and females. Same results were observed for the digit ratio of the left hand and the SPQ in the healthy total and healthy female subsample. Therefore, the inclusion of personality measures to study the link between the digit ratio and schizophrenia might help to provide insights in a potential continuum from healthy to schizophrenic behavior.
Use of the 'Precessions' process for prepolishing and correcting 2D & 2(1/2)D form.
Walker, David D; Freeman, Richard; Morton, Roger; McCavana, Gerry; Beaucamp, Anthony
2006-11-27
The Precessions process polishes complex surfaces from the ground state preserving the ground-in form, and subsequently rectifies measured form errors. Our first paper introduced the technology and focused on the novel tooling. In this paper we describe the unique CNC machine tools and how they operate in polishing and correcting form. Experimental results demonstrate both the '2D' and '2(1/2)D' form-correction modes, as applied to aspheres with rotationally-symmetric target-form.
Zhu, Xiaolei; Malbon, Christopher L; Yarkony, David R
2016-03-28
In a recent work we constructed a quasi-diabatic representation, H(d), of the 1, 2, 3(1)A adiabatic states of phenol from high level multireference single and double excitation configuration interaction electronic structure data, energies, energy gradients, and derivative couplings. That H(d) accurately describes surface minima, saddle points, and also regions of strong nonadiabatic interactions, reproducing the locus of conical intersection seams and the coordinate dependence of the derivative couplings. The present work determines the accuracy of H(d) for describing phenol photodissociation. Additionally, we demonstrate that a modest energetic shift of two diabats yields a quantifiably more accurate H(d) compared with experimental energetics. The analysis shows that in favorable circumstances it is possible to use single point energies obtained from the most reliable electronic structure methods available, including methods for which the energy gradients and derivative couplings are not available, to improve the quality of a global representation of several coupled potential energy surfaces. Our data suggest an alternative interpretation of kinetic energy release measurements near λphot ∼ 248 nm.
NASA Astrophysics Data System (ADS)
Zhu, Xiaolei; Malbon, Christopher L.; Yarkony, David R.
2016-03-01
In a recent work we constructed a quasi-diabatic representation, Hd, of the 1, 2, 31A adiabatic states of phenol from high level multireference single and double excitation configuration interaction electronic structure data, energies, energy gradients, and derivative couplings. That Hd accurately describes surface minima, saddle points, and also regions of strong nonadiabatic interactions, reproducing the locus of conical intersection seams and the coordinate dependence of the derivative couplings. The present work determines the accuracy of Hd for describing phenol photodissociation. Additionally, we demonstrate that a modest energetic shift of two diabats yields a quantifiably more accurate Hd compared with experimental energetics. The analysis shows that in favorable circumstances it is possible to use single point energies obtained from the most reliable electronic structure methods available, including methods for which the energy gradients and derivative couplings are not available, to improve the quality of a global representation of several coupled potential energy surfaces. Our data suggest an alternative interpretation of kinetic energy release measurements near λphot ˜ 248 nm.
Atomistic methodologies for material properties of 2D materials at the nanoscale
NASA Astrophysics Data System (ADS)
Zhang, Zhen
Research on two dimensional (2D) materials, such as graphene and MoS2, now involves thousands of researchers worldwide cutting across physics, chemistry, engineering and biology. Due to the extraordinary properties of 2D materials, research extends from fundamental science to novel applications of 2D materials. From an engineering point of view, understanding the material properties of 2D materials under various conditions is crucial for tailoring the electrical and mechanical properties of 2D-material-based devices at the nanoscale. Even at the nanoscale, molecular systems typically consist of a vast number of atoms. Molecular dynamics (MD) simulations enable us to understand the properties of assemblies of molecules in terms of their structure and the microscopic interactions between them. From a continuum approach, mechanical properties and thermal properties, such as strain, stress, and heat capacity, are well defined and experimentally measurable. In MD simulations, material systems are considered to be discrete, and only interatomic potential, interatomic forces, and atom positions are directly obtainable. Besides, most of the fracture mechanics concepts, such as stress intensity factors, are not applicable since there is no singularity in MD simulations. However, energy release rate still remains to be a feasible and crucial physical quantity to characterize the fracture mechanical property of materials at the nanoscale. Therefore, equivalent definition of a physical quantity both in atomic scale and macroscopic scale is necessary in order to understand molecular and continuum scale phenomena concurrently. This work introduces atomistic simulation methodologies, based on interatomic potential and interatomic forces, as a tool to unveil the mechanical properties, thermal properties and fracture mechanical properties of 2D materials at the nanoscale. Among many 2D materials, graphene and MoS2 have attracted intense interest. Therefore, we applied our
2D and 3D Numerical Simulations of Flux Cancellation
NASA Technical Reports Server (NTRS)
Karpen, Judith T.; DeVore, C.; Antiochos, S. K.; Linton, M. G.
2009-01-01
Cancellation of magnetic flux in the solar photosphere and chromosphere has been linked observationally and theoretically to a broad range of solar activity, from filament channel formation to CME initiation. Because this phenomenon is typically measured at only a single layer in the atmosphere, in the radial (line of sight) component of the magnetic field, the actual processes behind this observational signature are ambiguous. It is clear that reconnection is involved in some way, but the location of the reconnection sites and associated connectivity changes remain uncertain in most cases. We are using numerical modeling to demystify flux cancellation, beginning with the simplest possible configuration: a subphotospheric Lundquist flux tube surrounded by a potential field, immersed in a gravitationally stratified atmosphere, spanning many orders of magnitude in plasma beta. In this system, cancellation is driven slowly by a 2-cell circulation pattern imposed in the convection zone, such that the tops of the cells are located around the beta=1 level (i.e., the photosphere) and the flows converge and form a downdraft at the polarity inversion line; note however that no flow is imposed along the neutral line. We will present the results of 2D and 3D MHD-AMR simulations of flux cancellation, in which the flux at the photosphere begins in either an unsheared or sheared state. In all cases, a low-lying flux rope is formed by reconnection at the polarity inversion line within a few thousand seconds. The flux rope remains stable and does not rise, however, in contrast to models which do not include the presence of significant mass loading.
Spin Circuit Model for 2D Channels with Spin-Orbit Coupling
NASA Astrophysics Data System (ADS)
Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo
2016-03-01
In this paper we present a general theory for an arbitrary 2D channel with “spin momentum locking” due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, -). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U-, and D-. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green’s function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling.
Spin Circuit Model for 2D Channels with Spin-Orbit Coupling.
Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo
2016-01-01
In this paper we present a general theory for an arbitrary 2D channel with "spin momentum locking" due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, -). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U-, and D-. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green's function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling.
Spin Circuit Model for 2D Channels with Spin-Orbit Coupling.
Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo
2016-01-01
In this paper we present a general theory for an arbitrary 2D channel with "spin momentum locking" due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, -). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U-, and D-. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green's function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling. PMID:26932563
Mean flow and anisotropic cascades in decaying 2D turbulence
NASA Astrophysics Data System (ADS)
Liu, Chien-Chia; Cerbus, Rory; Gioia, Gustavo; Chakraborty, Pinaki
2015-11-01
Many large-scale atmospheric and oceanic flows are decaying 2D turbulent flows embedded in a non-uniform mean flow. Despite its importance for large-scale weather systems, the affect of non-uniform mean flows on decaying 2D turbulence remains unknown. In the absence of mean flow it is well known that decaying 2D turbulent flows exhibit the enstrophy cascade. More generally, for any 2D turbulent flow, all computational, experimental and field data amassed to date indicate that the spectrum of longitudinal and transverse velocity fluctuations correspond to the same cascade, signifying isotropy of cascades. Here we report experiments on decaying 2D turbulence in soap films with a non-uniform mean flow. We find that the flow transitions from the usual isotropic enstrophy cascade to a series of unusual and, to our knowledge, never before observed or predicted, anisotropic cascades where the longitudinal and transverse spectra are mutually independent. We discuss implications of our results for decaying geophysical turbulence.
Ultrafast 2D NMR: an emerging tool in analytical spectroscopy.
Giraudeau, Patrick; Frydman, Lucio
2014-01-01
Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy is widely used in chemical and biochemical analyses. Multidimensional NMR is also witnessing increased use in quantitative and metabolic screening applications. Conventional 2D NMR experiments, however, are affected by inherently long acquisition durations, arising from their need to sample the frequencies involved along their indirect domains in an incremented, scan-by-scan nature. A decade ago, a so-called ultrafast (UF) approach was proposed, capable of delivering arbitrary 2D NMR spectra involving any kind of homo- or heteronuclear correlation, in a single scan. During the intervening years, the performance of this subsecond 2D NMR methodology has been greatly improved, and UF 2D NMR is rapidly becoming a powerful analytical tool experiencing an expanded scope of applications. This review summarizes the principles and main developments that have contributed to the success of this approach and focuses on applications that have been recently demonstrated in various areas of analytical chemistry--from the real-time monitoring of chemical and biochemical processes, to extensions in hyphenated techniques and in quantitative applications. PMID:25014342
Latent heat induced rotation limited aggregation in 2D ice nanocrystals.
Bampoulis, Pantelis; Siekman, Martin H; Kooij, E Stefan; Lohse, Detlef; Zandvliet, Harold J W; Poelsema, Bene
2015-07-21
The basic science responsible for the fascinating shapes of ice crystals and snowflakes is still not understood. Insufficient knowledge of the interaction potentials and the lack of relevant experimental access to the growth process are to blame for this failure. Here, we study the growth of fractal nanostructures in a two-dimensional (2D) system, intercalated between mica and graphene. Based on our scanning tunneling spectroscopy data, we provide compelling evidence that these fractals are 2D ice. They grow while they are in material contact with the atmosphere at 20 °C and without significant thermal contact to the ambient. The growth is studied in situ, in real time and space at the nanoscale. We find that the growing 2D ice nanocrystals assume a fractal shape, which is conventionally attributed to Diffusion Limited Aggregation (DLA). However, DLA requires a low mass density mother phase, in contrast to the actual currently present high mass density mother phase. Latent heat effects and consequent transport of heat and molecules are found to be key ingredients for understanding the evolution of the snow (ice) flakes. We conclude that not the local availability of water molecules (DLA), but rather them having the locally required orientation is the key factor for incorporation into the 2D ice nanocrystal. In combination with the transport of latent heat, we attribute the evolution of fractal 2D ice nanocrystals to local temperature dependent rotation limited aggregation. The ice growth occurs under extreme supersaturation, i.e., the conditions closely resemble the natural ones for the growth of complex 2D snow (ice) flakes and we consider our findings crucial for solving the "perennial" snow (ice) flake enigma. PMID:26203037
Latent heat induced rotation limited aggregation in 2D ice nanocrystals
NASA Astrophysics Data System (ADS)
Bampoulis, Pantelis; Siekman, Martin H.; Kooij, E. Stefan; Lohse, Detlef; Zandvliet, Harold J. W.; Poelsema, Bene
2015-07-01
The basic science responsible for the fascinating shapes of ice crystals and snowflakes is still not understood. Insufficient knowledge of the interaction potentials and the lack of relevant experimental access to the growth process are to blame for this failure. Here, we study the growth of fractal nanostructures in a two-dimensional (2D) system, intercalated between mica and graphene. Based on our scanning tunneling spectroscopy data, we provide compelling evidence that these fractals are 2D ice. They grow while they are in material contact with the atmosphere at 20 °C and without significant thermal contact to the ambient. The growth is studied in situ, in real time and space at the nanoscale. We find that the growing 2D ice nanocrystals assume a fractal shape, which is conventionally attributed to Diffusion Limited Aggregation (DLA). However, DLA requires a low mass density mother phase, in contrast to the actual currently present high mass density mother phase. Latent heat effects and consequent transport of heat and molecules are found to be key ingredients for understanding the evolution of the snow (ice) flakes. We conclude that not the local availability of water molecules (DLA), but rather them having the locally required orientation is the key factor for incorporation into the 2D ice nanocrystal. In combination with the transport of latent heat, we attribute the evolution of fractal 2D ice nanocrystals to local temperature dependent rotation limited aggregation. The ice growth occurs under extreme supersaturation, i.e., the conditions closely resemble the natural ones for the growth of complex 2D snow (ice) flakes and we consider our findings crucial for solving the "perennial" snow (ice) flake enigma.
Image quality of up-converted 2D video from frame-compatible 3D video
NASA Astrophysics Data System (ADS)
Speranza, Filippo; Tam, Wa James; Vázquez, Carlos; Renaud, Ronald; Blanchfield, Phil
2011-03-01
In the stereoscopic frame-compatible format, the separate high-definition left and high-definition right views are reduced in resolution and packed to fit within the same video frame as a conventional two-dimensional high-definition signal. This format has been suggested for 3DTV since it does not require additional transmission bandwidth and entails only small changes to the existing broadcasting infrastructure. In some instances, the frame-compatible format might be used to deliver both 2D and 3D services, e.g., for over-the-air television services. In those cases, the video quality of the 2D service is bound to decrease since the 2D signal will have to be generated by up-converting one of the two views. In this study, we investigated such loss by measuring the perceptual image quality of 1080i and 720p up-converted video as compared to that of full resolution original 2D video. The video was encoded with either a MPEG-2 or a H.264/AVC codec at different bit rates and presented for viewing with either no polarized glasses (2D viewing mode) or with polarized glasses (3D viewing mode). The results confirmed a loss of video quality of the 2D video up-converted material. The loss due to the sampling processes inherent to the frame-compatible format was rather small for both 1080i and 720p video formats; the loss became more substantial with encoding, particularly for MPEG-2 encoding. The 3D viewing mode provided higher quality ratings, possibly because the visibility of the degradations was reduced.
Juhlin, C Christofer; Stenman, Adam; Haglund, Felix; Clark, Victoria E; Brown, Taylor C; Baranoski, Jacob; Bilguvar, Kaya; Goh, Gerald; Welander, Jenny; Svahn, Fredrika; Rubinstein, Jill C; Caramuta, Stefano; Yasuno, Katsuhito; Günel, Murat; Bäckdahl, Martin; Gimm, Oliver; Söderkvist, Peter; Prasad, Manju L; Korah, Reju; Lifton, Richard P; Carling, Tobias
2015-09-01
As subsets of pheochromocytomas (PCCs) lack a defined molecular etiology, we sought to characterize the mutational landscape of PCCs to identify novel gene candidates involved in disease development. A discovery cohort of 15 PCCs wild type for mutations in PCC susceptibility genes underwent whole-exome sequencing, and an additional 83 PCCs served as a verification cohort for targeted sequencing of candidate mutations. A low rate of nonsilent single nucleotide variants (SNVs) was detected (6.1/sample). Somatic HRAS and EPAS1 mutations were observed in one case each, whereas the remaining 13 cases did not exhibit variants in established PCC genes. SNVs aggregated in apoptosis-related pathways, and mutations in COSMIC genes not previously reported in PCCs included ZAN, MITF, WDTC1, and CAMTA1. Two somatic mutations and one constitutional variant in the well-established cancer gene lysine (K)-specific methyltransferase 2D (KMT2D, MLL2) were discovered in one sample each, prompting KMT2D screening using focused exome-sequencing in the verification cohort. An additional 11 PCCs displayed KMT2D variants, of which two were recurrent. In total, missense KMT2D variants were found in 14 (11 somatic, two constitutional, one undetermined) of 99 PCCs (14%). Five cases displayed somatic mutations in the functional FYR/SET domains of KMT2D, constituting 36% of all KMT2D-mutated PCCs. KMT2D expression was upregulated in PCCs compared to normal adrenals, and KMT2D overexpression positively affected cell migration in a PCC cell line. We conclude that KMT2D represents a recurrently mutated gene with potential implication for PCC development. PMID:26032282
Perception-based reversible watermarking for 2D vector maps
NASA Astrophysics Data System (ADS)
Men, Chaoguang; Cao, Liujuan; Li, Xiang
2010-07-01
This paper presents an effective and reversible watermarking approach for digital copyright protection of 2D-vector maps. To ensure that the embedded watermark is insensitive for human perception, we only select the noise non-sensitive regions for watermark embedding by estimating vertex density within each polyline. To ensure the exact recovery of original 2D-vector map after watermark extraction, we introduce a new reversible watermarking scheme based on reversible high-frequency wavelet coefficients modification. Within the former-selected non-sensitive regions, our watermarking operates on the lower-order vertex coordinate decimals with integer wavelet transform. Such operation further reduces the visual distortion caused by watermark embedding. We have validated the effectiveness of our scheme on our real-world city river/building 2D-vector maps. We give extensive experimental comparisons with state-of-the-art methods, including embedding capability, invisibility, and robustness over watermark attacking.
2D bifurcations and Newtonian properties of memristive Chua's circuits
NASA Astrophysics Data System (ADS)
Marszalek, W.; Podhaisky, H.
2016-01-01
Two interesting properties of Chua's circuits are presented. First, two-parameter bifurcation diagrams of Chua's oscillatory circuits with memristors are presented. To obtain various 2D bifurcation images a substantial numerical effort, possibly with parallel computations, is needed. The numerical algorithm is described first and its numerical code for 2D bifurcation image creation is available for free downloading. Several color 2D images and the corresponding 1D greyscale bifurcation diagrams are included. Secondly, Chua's circuits are linked to Newton's law φ ''= F(t,φ,φ')/m with φ=\\text{flux} , constant m > 0, and the force term F(t,φ,φ') containing memory terms. Finally, the jounce scalar equations for Chua's circuits are also discussed.
Focusing surface wave imaging with flexible 2D array
NASA Astrophysics Data System (ADS)
Zhou, Shiyuan; Fu, Junqiang; Li, Zhe; Xu, Chunguang; Xiao, Dingguo; Wang, Shaohan
2016-04-01
Curved surface is widely exist in key parts of energy and power equipment, such as, turbine blade cylinder block and so on. Cycling loading and harsh working condition of enable fatigue cracks appear on the surface. The crack should be found in time to avoid catastrophic damage to the equipment. A flexible 2D array transducer was developed. 2D Phased Array focusing method (2DPA), Mode-Spatial Double Phased focusing method (MSDPF) and the imaging method using the flexible 2D array probe are studied. Experiments using these focusing and imaging method are carried out. Surface crack image is obtained with both 2DPA and MSDPF focusing method. It have been proved that MSDPF can be more adaptable for curved surface and more calculate efficient than 2DPA.
National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China.
Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming
2016-01-01
Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7-99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9-99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines. PMID:27603206
National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China.
Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming
2016-01-01
Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7-99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9-99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines.
National Prociency Testing Result of CYP2D6*10 Genotyping for Adjuvant Tamoxifen Therapy in China
Lin, Guigao; Zhang, Kuo; Yi, Lang; Han, Yanxi; Xie, Jiehong; Li, Jinming
2016-01-01
Tamoxifen has been successfully used for treating breast cancer and preventing cancer recurrence. Cytochrome P450 2D6 (CYP2D6) plays a key role in the process of metabolizing tamoxifen to its active moiety, endoxifen. Patients with variants of the CYP2D6 gene may not receive the full benefit of tamoxifen treatment. The CYP2D6*10 variant (the most common variant in Asians) was analyzed to optimize the prescription of tamoxifen in China. To ensure referring clinicians have accurate information for genotype-guided tamoxifen treatment, the Chinese National Center for Clinical Laboratories (NCCL) organized a national proficiency testing (PT) to evaluate the performance of laboratories providing CYP2D6*10 genotyping. Ten genomic DNA samples with CYP2D6 wild-type or CYP2D6*10 variants were validated by PCR-sequencing and sent to 28 participant laboratories. The genotyping results and pharmacogenomic test reports were submitted and evaluated by NCCL experts. Additional information regarding the number of samples tested, the accreditation/certification status, and detecting technology was also requested. Thirty-one data sets were received, with a corresponding analytical sensitivity of 98.2% (548/558 challenges; 95% confidence interval: 96.7–99.1%) and an analytic specificity of 96.5% (675/682; 95% confidence interval: 97.9–99.5%). Overall, 25/28 participants correctly identified CYP2D6*10 status in 10 samples; however, two laboratories made serious genotyping errors. Most of the essential information was included in the 20 submitted CYP2D6*10 test reports. The majority of Chinese laboratories are reliable for detecting the CYP2D6*10 variant; however, several issues revealed in this study underline the importance of PT schemes in continued external assessment and provision of guidelines. PMID:27603206
The relationship between 2D static features and 2D dynamic features used in gait recognition
NASA Astrophysics Data System (ADS)
Alawar, Hamad M.; Ugail, Hassan; Kamala, Mumtaz; Connah, David
2013-05-01
In most gait recognition techniques, both static and dynamic features are used to define a subject's gait signature. In this study, the existence of a relationship between static and dynamic features was investigated. The correlation coefficient was used to analyse the relationship between the features extracted from the "University of Bradford Multi-Modal Gait Database". This study includes two dimensional dynamic and static features from 19 subjects. The dynamic features were compromised of Phase-Weighted Magnitudes driven by a Fourier Transform of the temporal rotational data of a subject's joints (knee, thigh, shoulder, and elbow). The results concluded that there are eleven pairs of features that are considered significantly correlated with (p<0.05). This result indicates the existence of a statistical relationship between static and dynamics features, which challenges the results of several similar studies. These results bare great potential for further research into the area, and would potentially contribute to the creation of a gait signature using latent data.
Radiative heat transfer in 2D Dirac materials.
Rodriguez-López, Pablo; Tse, Wang-Kong; Dalvit, Diego A R
2015-06-01
We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. Finally, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials. PMID:25965703
Quantum process tomography by 2D fluorescence spectroscopy
Pachón, Leonardo A.; Marcus, Andrew H.; Aspuru-Guzik, Alán
2015-06-07
Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.
Design of the LRP airfoil series using 2D CFD
NASA Astrophysics Data System (ADS)
Zahle, Frederik; Bak, Christian; Sørensen, Niels N.; Vronsky, Tomas; Gaudern, Nicholas
2014-06-01
This paper describes the design and wind tunnel testing of a high-Reynolds number, high lift airfoil series designed for wind turbines. The airfoils were designed using direct gradient- based numerical multi-point optimization based on a Bezier parameterization of the shape, coupled to the 2D Navier-Stokes flow solver EllipSys2D. The resulting airfoils, the LRP2-30 and LRP2-36, achieve both higher operational lift coefficients and higher lift to drag ratios compared to the equivalent FFA-W3 airfoils.
Laboratory Experiments On Continually Forced 2d Turbulence
NASA Astrophysics Data System (ADS)
Wells, M. G.; Clercx, H. J. H.; Van Heijst, G. J. F.
There has been much recent interest in the advection of tracers by 2D turbulence in geophysical flows. While there is a large body of literature on decaying 2D turbulence or forced 2D turbulence in unbounded domains, there have been very few studies of forced turbulence in bounded domains. In this study we present new experimental results from a continuously forced quasi 2D turbulent field. The experiments are performed in a square Perspex tank filled with water. The flow is made quasi 2D by a steady background rotation. The rotation rate of the tank has a small (<8 %) sinusoidal perturbation which leads to the periodic formation of eddies in the corners of the tank. When the oscillation period of the perturbation is greater than an eddy roll-up time-scale, dipole structures are observed to form. The dipoles can migrate away from the walls, and the interior of the tank is continually filled with vortexs. From experimental visualizations the length scale of the vortexs appears to be largely controlled by the initial formation mechanism and large scale structures are not observed to form at large times. Thus the experiments provide a simple way of cre- ating a continuously forced 2D turbulent field. The resulting structures are in contrast with most previous laboratory experiments on 2D turbulence which have investigated decaying turbulence and have observed the formations of large scale structure. In these experiments, decaying turbulence had been produced by a variety of methods such as the decaying turbulence in the wake of a comb of rods (Massen et al 1999), organiza- tion of vortices in thin conducting liquids (Cardoso et al 1994) or in rotating systems where there are sudden changes in angular rotation rate (Konijnenberg et al 1998). Results of dye visualizations, particle tracking experiments and a direct numerical simulation will be presented and discussed in terms of their oceanographic application. Bibliography Cardoso,O. Marteau, D. &Tabeling, P
2012-01-05
Code is for a layered electric medium with 2d structure. Includes air-earth interface at node z=2.. The electric ex and ez fields are calculated on edges of elemental grid and magnetic field hy is calculated on the face of the elemental grid. The code allows for a layered earth with 2d structures. Solutions of coupled first order Maxwell's equations are solved in the two dimensional environment using a finite- difference scheme on a staggered spationamore » and temporal grid.« less
Noninvasive deep Raman detection with 2D correlation analysis
NASA Astrophysics Data System (ADS)
Kim, Hyung Min; Park, Hyo Sun; Cho, Youngho; Jin, Seung Min; Lee, Kang Taek; Jung, Young Mee; Suh, Yung Doug
2014-07-01
The detection of poisonous chemicals enclosed in daily necessaries is prerequisite essential for homeland security with the increasing threat of terrorism. For the detection of toxic chemicals, we combined a sensitive deep Raman spectroscopic method with 2D correlation analysis. We obtained the Raman spectra from concealed chemicals employing spatially offset Raman spectroscopy in which incident line-shaped light experiences multiple scatterings before being delivered to inner component and yielding deep Raman signal. Furthermore, we restored the pure Raman spectrum of each component using 2D correlation spectroscopic analysis with chemical inspection. Using this method, we could elucidate subsurface component under thick powder and packed contents in a bottle.
NASA Astrophysics Data System (ADS)
Hosomichi, Kazuo; Lee, Sungjay
2015-01-01
We study the system of M2-branes suspended between parallel M5-branes using ABJM model with a natural half-BPS boundary condition. For small separation between M5-branes, the worldvolume theory is shown to reduce to a 2D super Yang-Mills theory with some similarity to q-deformed Yang-Mills theory. The gauge coupling is related to the position of the branes in an interesting manner. The theory is considerably different from the 2D theory proposed for multiple "M-strings". We make a detailed comparison of elliptic genus of the two descriptions and find only a partial agreement.
Finite temperature corrections in 2d integrable models
NASA Astrophysics Data System (ADS)
Caselle, M.; Hasenbusch, M.
2002-09-01
We study the finite size corrections for the magnetization and the internal energy of the 2d Ising model in a magnetic field by using transfer matrix techniques. We compare these corrections with the functional form recently proposed by Delfino and LeClair-Mussardo for the finite temperature behaviour of one-point functions in integrable 2d quantum field theories. We find a perfect agreement between theoretical expectations and numerical results. Assuming the proposed functional form as an input in our analysis we obtain a relevant improvement in the precision of the continuum limit estimates of both quantities.
2dF grows up: Echidna for the AAT
NASA Astrophysics Data System (ADS)
McGrath, Andrew; Barden, Sam; Miziarski, Stan; Rambold, William; Smith, Greg
2008-07-01
We present the concept design of a new fibre positioner and spectrograph system for the Anglo-Australian Telescope, as a proposed enhancement to the Anglo-Australian Observatory's well-known 2dF facility. A four-fold multiplex enhancement is accomplished by replacing the 400-fibre 2dF fibre positioning robot with a 1600-fibre Echidna unit, feeding three clones of the AAOmega optical spectrograph. Such a facility has the capability of a redshift 1 survey of a large fraction of the southern sky, collecting five to ten thousand spectra per night for a million-galaxy survey.
Radiative heat transfer in 2D Dirac materials
Rodriguez-López, Pablo; Tse, Wang -Kong; Dalvit, Diego A. R.
2015-05-12
We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. In conclusion, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials.
Nomenclature for human CYP2D6 alleles.
Daly, A K; Brockmöller, J; Broly, F; Eichelbaum, M; Evans, W E; Gonzalez, F J; Huang, J D; Idle, J R; Ingelman-Sundberg, M; Ishizaki, T; Jacqz-Aigrain, E; Meyer, U A; Nebert, D W; Steen, V M; Wolf, C R; Zanger, U M
1996-06-01
To standardize CYP2D6 allele nomenclature, and to conform with international human gene nomenclature guidelines, an alternative to the current arbitrary system is described. Based on recommendations for human genome nomenclature, we propose that alleles be designated by CYP2D6 followed by an asterisk and a combination of roman letters and arabic numerals distinct for each allele with the number specifying the key mutation and, where appropriate, a letter specifying additional mutations. Criteria for classification as a separate allele and protein nomenclature are also presented. PMID:8807658
Spreading dynamics of 2D dipolar Langmuir monolayer phases.
Heinig, P; Wurlitzer, S; Fischer, Th M
2004-07-01
We study the spreading of a liquid 2D dipolar droplet in a Langmuir monolayer. Interfacial tensions (line tensions) and microscopic contact angles depend on the scale on which they are probed and obey a scaling law. Assuming rapid equilibration of the microscopic contact angle and ideal slippage of the 2D solid/liquid and solid/gas boundary, the driving force of spreading is merely expressed by the shape-dependent long-range interaction integrals. We obtain good agreement between experiment and numerical simulations using this theory. PMID:15278693
Evaluation of 2D ceramic matrix composites in aeroconvective environments
NASA Technical Reports Server (NTRS)
Riccitiello, Salvatore R.; Love, Wendell L.; Balter-Peterson, Aliza
1992-01-01
An evaluation is conducted of a novel ceramic-matrix composite (CMC) material system for use in the aeroconvective-heating environments encountered by the nose caps and wing leading edges of such aerospace vehicles as the Space Shuttle, during orbit-insertion and reentry from LEO. These CMCs are composed of an SiC matrix that is reinforced with Nicalon, Nextel, or carbon refractory fibers in a 2D architecture. The test program conducted for the 2D CMCs gave attention to their subsurface oxidation.
Quantum process tomography by 2D fluorescence spectroscopy
NASA Astrophysics Data System (ADS)
Pachón, Leonardo A.; Marcus, Andrew H.; Aspuru-Guzik, Alán
2015-06-01
Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.
Ruck, Tobias; Bittner, Stefan; Afzali, Ali Maisam; Göbel, Kerstin; Glumm, Sarah; Kraft, Peter; Sommer, Claudia; Kleinschnitz, Christoph; Preuße, Corinna; Stenzel, Werner; Wiendl, Heinz; Meuth, Sven G
2015-12-22
NKG2D is an activating receptor on T cells, which has been implicated in the pathogenesis of autoimmune diseases. T cells are critically involved in idiopathic inflammatory myopathies (IIM) and have been proposed as specific therapeutic targets. However, the mechanisms underlying T cell-mediated progressive muscle destruction in IIM remain to be elucidated. We here determined the involvement of the NKG2D - IL-15 signaling pathway. Primary human myoblasts expressed NKG2D ligands, which were further upregulated upon inflammatory stimuli. In parallel, shedding of the soluble NKG2D ligand MICA (sMICA) decreased upon inflammation potentially diminishing inhibition of NKG2D signaling. Membrane-related expression of IL-15 by myoblasts induced differentiation of naïve CD8+ T cells into highly activated, cytotoxic CD8+NKG2Dhigh T cells demonstrating NKG2D-dependent lysis of myoblasts in vitro. CD8+NKG2Dhigh T cell frequencies were increased in the peripheral blood of polymyositis (PM) patients and correlated with serum creatinine kinase concentrations, while serum sMICA levels were not significantly changed. In muscle biopsy specimens from PM patients expression of the NKG2D ligand MICA/B was upregulated, IL-15 was expressed by muscle cells, CD68+ macrophages as well as CD4+ T cells, and CD8+NKG2D+ cells were frequently detected within inflammatory infiltrates arguing for a local signaling circuit in the inflammatory muscle milieu. In conclusion, the NKG2D - IL-15 signaling pathway contributes to progressive muscle destruction in IIM potentially opening new therapeutic avenues. PMID:26646698
Ruck, Tobias; Bittner, Stefan; Afzali, Ali Maisam; Göbel, Kerstin; Glumm, Sarah; Kraft, Peter; Sommer, Claudia; Kleinschnitz, Christoph; Preuβe, Corinna; Stenzel, Werner
2015-01-01
NKG2D is an activating receptor on T cells, which has been implicated in the pathogenesis of autoimmune diseases. T cells are critically involved in idiopathic inflammatory myopathies (IIM) and have been proposed as specific therapeutic targets. However, the mechanisms underlying T cell-mediated progressive muscle destruction in IIM remain to be elucidated. We here determined the involvement of the NKG2D – IL-15 signaling pathway. Primary human myoblasts expressed NKG2D ligands, which were further upregulated upon inflammatory stimuli. In parallel, shedding of the soluble NKG2D ligand MICA (sMICA) decreased upon inflammation potentially diminishing inhibition of NKG2D signaling. Membrane-related expression of IL-15 by myoblasts induced differentiation of naïve CD8+ T cells into highly activated, cytotoxic CD8+NKG2Dhigh T cells demonstrating NKG2D-dependent lysis of myoblasts in vitro. CD8+NKG2Dhigh T cell frequencies were increased in the peripheral blood of polymyositis (PM) patients and correlated with serum creatinine kinase concentrations, while serum sMICA levels were not significantly changed. In muscle biopsy specimens from PM patients expression of the NKG2D ligand MICA/B was upregulated, IL-15 was expressed by muscle cells, CD68+ macrophages as well as CD4+ T cells, and CD8+NKG2D+ cells were frequently detected within inflammatory infiltrates arguing for a local signaling circuit in the inflammatory muscle milieu. In conclusion, the NKG2D – IL-15 signaling pathway contributes to progressive muscle destruction in IIM potentially opening new therapeutic avenues. PMID:26646698
Progress in Complex 2D and 3D Cohesive Fracture Modelling Considering Random Heterogeneity
NASA Astrophysics Data System (ADS)
Yang, Zhenjun; Su, Xiangting; Chen, Jianfei; Liu, Guohua
2010-05-01
This paper summarises our recent efforts on finite element modelling of complex 2D and 3D fracture in quasi-brittle materials considering random heterogeneous fracture properties, using a simple yet effective method developed in associated with Abaqus. In this method, potential cracks are represented by pre-inserted cohesive elements with traction-separation softening constitutive laws modelled by spatially-varying Weibull random fields. Extensive Monte Carlo simulations of small-sized concrete specimens under uni-axial tension were carried out. It is found that the developed method is able to predict realistic 2D and 3D crack propagation processes and excellent load-displacement curves with little mesh-dependence. It provides a potentially powerful tool to assess reliability of existing structures against external loadings.
The inspection of anisotropic single-crystal components using a 2-D ultrasonic array.
Lane, Christopher J L; Dunhill, A K; Drinkwater, Bruce W; Wilcox, Paul D
2010-12-01
Single-crystal metal alloys are used extensively in the manufacture of jet engine components for their excellent mechanical properties at elevated temperatures. The inspection of these components using 2-D ultrasonic arrays potentially allows the detection of subsurface defects in threedimensions from one inspection location. Such methods are not currently suitable for the inspection of single-crystal components because the high elastic anisotropy of single-crystal materials causes directional variation in ultrasonic waves. In this paper, a model of wave propagation in anisotropic material is used to correct an ultrasonic imaging algorithm and is applied to a single-crystal test specimen. For this correctedalgorithm, the orientation of the crystal in a specimen must be known before the inspection. Using the same ultrasonic array to measure the orientation and perform the defect inspection offers the most practical solution. Therefore, potential crystallographic orientation methods using 2-D ultrasonic arrays are also developed and evaluated. PMID:21156370
Band Gap Engineering in a 2D Material for Solar-to-Chemical Energy Conversion.
Hu, Jun; Guo, Zhenkun; Mcwilliams, Peter E; Darges, John E; Druffel, Daniel L; Moran, Andrew M; Warren, Scott C
2016-01-13
The electronic structure of 2D semiconductors depends on their thickness, providing new opportunities to engineer semiconductors for energy conversion, electronics, and catalysis. Here we show how a 3D semiconductor, black phosphorus, becomes active for solar-to-chemical energy conversion when it is thinned to a 2D material. The increase in its band gap, from 0.3 eV (3D) to 2.1 eV (2D monolayer), is accompanied by a 40-fold enhancement in the formation of chemical products. Despite this enhancement, smaller flakes also have shorter excited state lifetimes. We deduce a mechanism in which recombination occurs at flake edges, while the "van der Waals" surface of black phosphorus bonds to chemical intermediates and facilitates electron transfer. The unique properties of black phosphorus highlight its potential as a customizable material for solar energy conversion and catalysis, while also allowing us to identify design rules for 2D photocatalysts that will enable further improvements in these materials. PMID:26651872
Modulation of cortical activity in 2D versus 3D virtual reality environments: an EEG study.
Slobounov, Semyon M; Ray, William; Johnson, Brian; Slobounov, Elena; Newell, Karl M
2015-03-01
There is a growing empirical evidence that virtual reality (VR) is valuable for education, training, entertaining and medical rehabilitation due to its capacity to represent real-life events and situations. However, the neural mechanisms underlying behavioral confounds in VR environments are still poorly understood. In two experiments, we examined the effect of fully immersive 3D stereoscopic presentations and less immersive 2D VR environments on brain functions and behavioral outcomes. In Experiment 1 we examined behavioral and neural underpinnings of spatial navigation tasks using electroencephalography (EEG). In Experiment 2, we examined EEG correlates of postural stability and balance. Our major findings showed that fully immersive 3D VR induced a higher subjective sense of presence along with enhanced success rate of spatial navigation compared to 2D. In Experiment 1 power of frontal midline EEG (FM-theta) was significantly higher during the encoding phase of route presentation in the 3D VR. In Experiment 2, the 3D VR resulted in greater postural instability and modulation of EEG patterns as a function of 3D versus 2D environments. The findings support the inference that the fully immersive 3D enriched-environment requires allocation of more brain and sensory resources for cognitive/motor control during both tasks than 2D presentations. This is further evidence that 3D VR tasks using EEG may be a promising approach for performance enhancement and potential applications in clinical/rehabilitation settings. PMID:25448267
Application Of Metric Space Technique (mst) In 2-d And 3-d To Sdss Dr5
NASA Astrophysics Data System (ADS)
Wu, Yongfeng; Batuski, D. J.; Khalil, A.
2009-01-01
The Metric Space Technique (MST) is a 2-D analysis method using multiple measures for quantitative analysis of any type of structure in an `image'. All potential values of the measures for such distributions are thus coordinates in a multi-parameter space, and the analysis is based on considering a sample's measures (called `output functions'), and their distance from the origin, which corresponds to the measures of the observed SDSS sample, in this multi-parameter space. Applications of this method to thin (approximately 2-D) slices of SDSS DR5 have yielded a detailed comparison of numerical models (Berlind et al. 2006, Croton et al. 2005) against the SDSS galaxy 2-D distribution structure in multi-parameter space. We present those results, including discussion of the effects of transforming from physical space to redshift space on the statistics at different scales. We also extended this 2-D method into 3-D, and we present comparisons of the SDSS galaxy 3-D distribution versus the same numerical simulations.
Experimental studies of spin-imbalanced Fermi gases in 2D geometries
NASA Astrophysics Data System (ADS)
Thomas, John
We study the thermodynamics of a quasi-two-dimensional Fermi gas, which is not quite two-dimensional (2D), but far from three dimensional (3D). This system offers opportunities to test predictions that cross interdisciplinary boundaries, such as enhanced superfluid transition temperatures in spin-imbalanced quasi-2D superconductors, and provides important benchmarks for calculations of the phase diagrams. In the experiments, an ultra-cold Fermi gas is confined in an infrared CO2 laser standing-wave, which produces periodic pancake-shaped potential wells, separated by 5.3 μm. To study the thermodynamics, we load an ultra-cold mixture of N1 = 800 spin 1/2 -up and N2
Roton Excitations and the Fluid-Solid Phase Transition in Superfluid 2D Yukawa Bosons
NASA Astrophysics Data System (ADS)
Molinelli, S.; Galli, D. E.; Reatto, L.; Motta, M.
2016-10-01
We compute several ground-state properties and the dynamical structure factor of a zero-temperature system of Bosons interacting with the 2D screened Coulomb (2D-SC) potential. We resort to the exact shadow path integral ground state (SPIGS) quantum Monte Carlo method to compute the imaginary-time correlation function of the model, and to the genetic algorithm via falsification of theories (GIFT) to retrieve the dynamical structure factor. We provide a detailed comparison of ground-state properties and collective excitations of 2D-SC and ^4He atoms. The roton energy of the 2D-SC system is an increasing function of density, and not a decreasing one as in ^4He. This result is in contrast with the view that the roton is the soft mode of the fluid-solid transition. We uncover a remarkable quasi-universality of backflow and of other properties when expressed in terms of the amount of short-range order as quantified by the height of the first peak of the static structure factor.
Band Gap Engineering in a 2D Material for Solar-to-Chemical Energy Conversion.
Hu, Jun; Guo, Zhenkun; Mcwilliams, Peter E; Darges, John E; Druffel, Daniel L; Moran, Andrew M; Warren, Scott C
2016-01-13
The electronic structure of 2D semiconductors depends on their thickness, providing new opportunities to engineer semiconductors for energy conversion, electronics, and catalysis. Here we show how a 3D semiconductor, black phosphorus, becomes active for solar-to-chemical energy conversion when it is thinned to a 2D material. The increase in its band gap, from 0.3 eV (3D) to 2.1 eV (2D monolayer), is accompanied by a 40-fold enhancement in the formation of chemical products. Despite this enhancement, smaller flakes also have shorter excited state lifetimes. We deduce a mechanism in which recombination occurs at flake edges, while the "van der Waals" surface of black phosphorus bonds to chemical intermediates and facilitates electron transfer. The unique properties of black phosphorus highlight its potential as a customizable material for solar energy conversion and catalysis, while also allowing us to identify design rules for 2D photocatalysts that will enable further improvements in these materials.
NASA Technical Reports Server (NTRS)
Gao, Shou-Ting; Ping, Fan; Li, Xiao-Fan; Tao, Wei-Kuo
2004-01-01
Although dry/moist potential vorticity is a useful physical quantity for meteorological analysis, it cannot be applied to the analysis of 2D simulations. A convective vorticity vector (CVV) is introduced in this study to analyze 2D cloud-resolving simulation data associated with 2D tropical convection. The cloud model is forced by the vertical velocity, zonal wind, horizontal advection, and sea surface temperature obtained from the TOGA COARE, and is integrated for a selected 10-day period. The CVV has zonal and vertical components in the 2D x-z frame. Analysis of zonally-averaged and mass-integrated quantities shows that the correlation coefficient between the vertical component of the CVV and the sum of the cloud hydrometeor mixing ratios is 0.81, whereas the correlation coefficient between the zonal component and the sum of the mixing ratios is only 0.18. This indicates that the vertical component of the CVV is closely associated with tropical convection. The tendency equation for the vertical component of the CVV is derived and the zonally-averaged and mass-integrated tendency budgets are analyzed. The tendency of the vertical component of the CVV is determined by the interaction between the vorticity and the zonal gradient of cloud heating. The results demonstrate that the vertical component of the CVV is a cloud-linked parameter and can be used to study tropical convection.
Genomics of Dementia: APOE- and CYP2D6-Related Pharmacogenetics
Cacabelos, Ramón; Martínez, Rocío; Fernández-Novoa, Lucía; Carril, Juan C.; Lombardi, Valter; Carrera, Iván; Corzo, Lola; Tellado, Iván; Leszek, Jerzy; McKay, Adam; Takeda, Masatoshi
2012-01-01
Dementia is a major problem of health in developed societies. Alzheimer's disease (AD), vascular dementia, and mixed dementia account for over 90% of the most prevalent forms of dementia. Both genetic and environmental factors are determinant for the phenotypic expression of dementia. AD is a complex disorder in which many different gene clusters may be involved. Most genes screened to date belong to different proteomic and metabolomic pathways potentially affecting AD pathogenesis. The ε4 variant of the APOE gene seems to be a major risk factor for both degenerative and vascular dementia. Metabolic factors, cerebrovascular disorders, and epigenetic phenomena also contribute to neurodegeneration. Five categories of genes are mainly involved in pharmacogenomics: genes associated with disease pathogenesis, genes associated with the mechanism of action of a particular drug, genes associated with phase I and phase II metabolic reactions, genes associated with transporters, and pleiotropic genes and/or genes associated with concomitant pathologies. The APOE and CYP2D6 genes have been extensively studied in AD. The therapeutic response to conventional drugs in patients with AD is genotype specific, with CYP2D6-PMs, CYP2D6-UMs, and APOE-4/4 carriers acting as the worst responders. APOE and CYP2D6 may cooperate, as pleiotropic genes, in the metabolism of drugs and hepatic function. The introduction of pharmacogenetic procedures into AD pharmacological treatment may help to optimize therapeutics. PMID:22482072
Roton Excitations and the Fluid-Solid Phase Transition in Superfluid 2D Yukawa Bosons
NASA Astrophysics Data System (ADS)
Molinelli, S.; Galli, D. E.; Reatto, L.; Motta, M.
2016-05-01
We compute several ground-state properties and the dynamical structure factor of a zero-temperature system of Bosons interacting with the 2D screened Coulomb (2D-SC) potential. We resort to the exact shadow path integral ground state (SPIGS) quantum Monte Carlo method to compute the imaginary-time correlation function of the model, and to the genetic algorithm via falsification of theories (GIFT) to retrieve the dynamical structure factor. We provide a detailed comparison of ground-state properties and collective excitations of 2D-SC and ^4 He atoms. The roton energy of the 2D-SC system is an increasing function of density, and not a decreasing one as in ^4 He. This result is in contrast with the view that the roton is the soft mode of the fluid-solid transition. We uncover a remarkable quasi-universality of backflow and of other properties when expressed in terms of the amount of short-range order as quantified by the height of the first peak of the static structure factor.
Song, Hyunkeun; Park, Hyunjin; Park, Gabin; Kim, Yeong Seok; Lee, Hyun-Kyung; Jin, Dong-Hoon; Kang, Hyung-Sik; Cho, Dae-Ho; Hur, Daeyoung
2014-07-01
Corticotropin-releasing factor (CRF), a coordinator of the body's responses to stress, is found in various cancer tissues and cell lines. However, the exact abilities of CRF to manipulate natural killer (NK) cells during immune response have not been studied. NKG2D is an activating receptor that is expressed on most NK and CD8+ T cells. MHC class I-related chain A (MICA) and UL16-binding protein (ULBP) 1, 2 and 3 are well-known ligands for NKG2D. In the present study, we reported our findings regarding the role of CRF in cervical cancer cell survival. Human cervical cancer cell line, HeLa cells, had significantly higher intracellular expression of UL16-binding protein 2 (ULBP2) following CRF treatment but had only slightly increased surface expression of ULBP2. Notably, MMPi (pan-metalloproteases inhibitor) blocked the release of ULBP2 molecules from the surface of HeLa cells. Furthermore, incubating NK cells with culture supernatants from CRF-treated HeLa cells, which contained soluble NKG2D ligand, reduced NK cell activity by decreasing surface expression of NKG2D. Collectively, downregulation of NKG2D by CRF-induced soluble NKG2D ligand provides a potential mechanism by which cervical cancer cells escape NKG2D-mediated attack under stress conditions.
Non-linear effects in quantitative 2D NMR of polysaccharides: pitfalls and how to avoid them.
Martineau, Estelle; El Khantache, Kamel; Pupier, Marion; Sepulcri, Patricia; Akoka, Serge; Giraudeau, Patrick
2015-04-10
Quantitative 2D NMR is a powerful analytical tool which is widely used to determine the concentration of small molecules in complex samples. Due to the site-specific response of the 2D NMR signal, the determination of absolute concentrations requires the use of a calibration or standard addition approach, where the analyte acts as its own reference. Standard addition methods, where the targeted sample is gradually spiked with known amounts of the targeted analyte, are particularly well-suited for quantitative 2D NMR of small molecules. This paper explores the potential of such quantitative 2D NMR approaches for the quantitative analysis of a high molecular weight polysaccharide. The results highlight that the standard addition method leads to a strong under-estimation of the target concentration, whatever the 2D NMR pulse sequence. Diffusion measurements show that a change in the macromolecular organization of the studied polysaccharide is the most probable hypothesis to explain the non-linear evolution of the 2D NMR signal with concentration. In spite of this non-linearity--the detailed explanation of which is out of the scope of this paper--we demonstrate that accurate quantitative results can still be obtained provided that an external calibration is performed with a wide range of concentrations surrounding the target value. This study opens the way to a number of studies where 2D NMR is needed for the quantitative analysis of macromolecules.
Almost but not quite 2D, Non-linear Bayesian Inversion of CSEM Data
NASA Astrophysics Data System (ADS)
Ray, A.; Key, K.; Bodin, T.
2013-12-01
The geophysical inverse problem can be elegantly stated in a Bayesian framework where a probability distribution can be viewed as a statement of information regarding a random variable. After all, the goal of geophysical inversion is to provide information on the random variables of interest - physical properties of the earth's subsurface. However, though it may be simple to postulate, a practical difficulty of fully non-linear Bayesian inversion is the computer time required to adequately sample the model space and extract the information we seek. As a consequence, in geophysical problems where evaluation of a full 2D/3D forward model is computationally expensive, such as marine controlled source electromagnetic (CSEM) mapping of the resistivity of seafloor oil and gas reservoirs, Bayesian studies have largely been conducted with 1D forward models. While the 1D approximation is indeed appropriate for exploration targets with planar geometry and geological stratification, it only provides a limited, site-specific idea of uncertainty in resistivity with depth. In this work, we extend our fully non-linear 1D Bayesian inversion to a 2D model framework, without requiring the usual regularization of model resistivities in the horizontal or vertical directions used to stabilize quasi-2D inversions. In our approach, we use the reversible jump Markov-chain Monte-Carlo (RJ-MCMC) or trans-dimensional method and parameterize the subsurface in a 2D plane with Voronoi cells. The method is trans-dimensional in that the number of cells required to parameterize the subsurface is variable, and the cells dynamically move around and multiply or combine as demanded by the data being inverted. This approach allows us to expand our uncertainty analysis of resistivity at depth to more than a single site location, allowing for interactions between model resistivities at different horizontal locations along a traverse over an exploration target. While the model is parameterized in 2D, we
A comment on the rank correlation merit function for 2D/3D registration
NASA Astrophysics Data System (ADS)
Figl, Michael; Bloch, Christoph; Birkfellner, Wolfgang
2010-02-01
Lots of procedures in computer assisted interventions register pre-interventionally generated 3D data sets to the intraoperative situation using fast and simply generated 2D images, e.g. from a C-Arm, a B-mode Ultrasound, etc. Registration is typically done by generating a 2D image out of the 3D data set, comparison to the original 2D image using a planar similarity measure and subsequent optimisation. As these two images can be very different, a lot of different comparison functions are in use. In a recent article Stochastic Rank Correlation, a merit function based on Spearman's rank correlation coefficient was presented. By comparing randomly chosen subsets of the images, the authors wanted to avoid the computational expense of sorting all the points in the image. In the current paper we show that, because of the limited grey level range in medical images, full image rank correlation can be computed almost as fast as Pearson's correlation coefficient. A run time estimation is illustrated with numerical results using a 2D Shepp-Logan phantom at different sizes, and a sample data set of a pig.
Global synthetic seismograms using a 2-D finite-difference method
NASA Astrophysics Data System (ADS)
Li, Dunzhu; Helmberger, Don; Clayton, Robert W.; Sun, Daoyuan
2014-05-01
Two-dimensional (2-D) finite-difference (FD) synthetics, which fill the gap between fast 1-D analytic synthetics and time-consuming full 3-D synthetics in our ability to model seismograms, have been used in many studies. We address several issues involving 2-D FD methods in generating global synthetic seismograms. These include: (1) interfacing point source excitation for earthquakes with 2-D FD methods; (2) out-of-plane spreading corrections and (3) reducing the spherical Earth to the flattened models. The first issue is tackled using two methods, a `transparent source box' approach and a moment tensor excitation approach, where each has its own advantages. Moreover, our `source box' excitation does not have the late-time drift problem that occurred in previous studies. The out-of-plane geometric spreading correction is accounted for by estimating the ray parameter and applying a post-simulation filter to 2-D synthetics. Finally, parameters of the Earth-flattening transformation are discussed and validated. The effectiveness of this method is demonstrated by comparing our synthetics with frequency-wavenumber summation, normal-mode and 3-D spectral-element synthetics.
2D-3D hybrid stabilized finite element method for tsunami runup simulations
NASA Astrophysics Data System (ADS)
Takase, S.; Moriguchi, S.; Terada, K.; Kato, J.; Kyoya, T.; Kashiyama, K.; Kotani, T.
2016-09-01
This paper presents a two-dimensional (2D)-three-dimensional (3D) hybrid stabilized finite element method that enables us to predict a propagation process of tsunami generated in a hypocentral region, which ranges from offshore propagation to runup to urban areas, with high accuracy and relatively low computational costs. To be more specific, the 2D shallow water equation is employed to simulate the propagation of offshore waves, while the 3D Navier-Stokes equation is employed for the runup in urban areas. The stabilized finite element method is utilized for numerical simulations for both of the 2D and 3D domains that are independently discretized with unstructured meshes. The multi-point constraint and transmission methods are applied to satisfy the continuity of flow velocities and pressures at the interface between the resulting 2D and 3D meshes, since neither their spatial dimensions nor node arrangements are consistent. Numerical examples are presented to demonstrate the performance of the proposed hybrid method to simulate tsunami behavior, including offshore propagation and runup to urban areas, with substantially lower computation costs in comparison with full 3D computations.
Realising the Full Potential of the Web.
ERIC Educational Resources Information Center
Berners-Lee, Tim
1999-01-01
Argues that the first phase of the Web is communication through shared knowledge. Predicts that the second side to the Web, yet to emerge, is that of machine-understandable information, with humans providing the inspiration and the intuition. (CR)
Discrepant Results in a 2-D Marble Collision
ERIC Educational Resources Information Center
Kalajian, Peter
2013-01-01
Video analysis of 2-D collisions is an excellent way to investigate conservation of linear momentum. The often-desired experimental design goal is to minimize the momentum loss in order to demonstrate the conservation law. An air table with colliding pucks is an ideal medium for this experiment, but such equipment is beyond the budget of many…
THz devices based on 2D electron systems
NASA Astrophysics Data System (ADS)
Xing, Huili Grace; Yan, Rusen; Song, Bo; Encomendero, Jimy; Jena, Debdeep
2015-05-01
In two-dimensional electron systems with mobility on the order of 1,000 - 10,000 cm2/Vs, the electron scattering time is about 1 ps. For the THz window of 0.3 - 3 THz, the THz photon energy is in the neighborhood of 1 meV, substantially smaller than the optical phonon energy of solids where these 2D electron systems resides. These properties make the 2D electron systems interesting as a platform to realize THz devices. In this paper, I will review 3 approaches investigated in the past few years in my group toward THz devices. The first approach is the conventional high electron mobility transistor based on GaN toward THz amplifiers. The second approach is to employ the tunable intraband absorption in 2D electron systems to realize THz modulators, where I will use graphene as a model material system. The third approach is to exploit plasma wave in these 2D electron systems that can be coupled with a negative differential conductance element for THz amplifiers/sources/detectors.
ELLIPT2D: A Flexible Finite Element Code Written Python
Pletzer, A.; Mollis, J.C.
2001-03-22
The use of the Python scripting language for scientific applications and in particular to solve partial differential equations is explored. It is shown that Python's rich data structure and object-oriented features can be exploited to write programs that are not only significantly more concise than their counter parts written in Fortran, C or C++, but are also numerically efficient. To illustrate this, a two-dimensional finite element code (ELLIPT2D) has been written. ELLIPT2D provides a flexible and easy-to-use framework for solving a large class of second-order elliptic problems. The program allows for structured or unstructured meshes. All functions defining the elliptic operator are user supplied and so are the boundary conditions, which can be of Dirichlet, Neumann or Robbins type. ELLIPT2D makes extensive use of dictionaries (hash tables) as a way to represent sparse matrices.Other key features of the Python language that have been widely used include: operator over loading, error handling, array slicing, and the Tkinter module for building graphical use interfaces. As an example of the utility of ELLIPT2D, a nonlinear solution of the Grad-Shafranov equation is computed using a Newton iterative scheme. A second application focuses on a solution of the toroidal Laplace equation coupled to a magnetohydrodynamic stability code, a problem arising in the context of magnetic fusion research.
NKG2D ligands mediate immunosurveillance of senescent cells.
Sagiv, Adi; Burton, Dominick G A; Moshayev, Zhana; Vadai, Ezra; Wensveen, Felix; Ben-Dor, Shifra; Golani, Ofra; Polic, Bojan; Krizhanovsky, Valery
2016-02-01
Cellular senescence is a stress response mechanism that limits tumorigenesis and tissue damage. Induction of cellular senescence commonly coincides with an immunogenic phenotype that promotes self-elimination by components of the immune system, thereby facilitating tumor suppression and limiting excess fibrosis during wound repair. The mechanisms by which senescent cells regulate their immune surveillance are not completely understood. Here we show that ligands of an activating Natural Killer (NK) cell receptor (NKG2D), MICA and ULBP2 are consistently up-regulated following induction of replicative senescence, oncogene-induced senescence and DNA damage - induced senescence. MICA and ULBP2 proteins are necessary for efficient NK-mediated cytotoxicity towards senescent fibroblasts. The mechanisms regulating the initial expression of NKG2D ligands in senescent cells are dependent on a DNA damage response, whilst continuous expression of these ligands is regulated by the ERK signaling pathway. In liver fibrosis, the accumulation of senescent activated stellate cells is increased in mice lacking NKG2D receptor leading to increased fibrosis. Overall, our results provide new insights into the mechanisms regulating the expression of immune ligands in senescent cells and reveal the importance of NKG2D receptor-ligand interaction in protecting against liver fibrosis. PMID:26878797
Proteomic Profiling of Macrophages by 2D Electrophoresis
Bouvet, Marion; Turkieh, Annie; Acosta-Martin, Adelina E.; Chwastyniak, Maggy; Beseme, Olivia; Amouyel, Philippe; Pinet, Florence
2014-01-01
The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The key role of macrophages has been shown in various pathological disorders such as inflammatory, immunological, and infectious diseases. In this protocol, we use primary cultures of human monocyte-derived macrophages that can be differentiated into the M1 (pro-inflammatory) or the M2 (anti-inflammatory) phenotype. This in vitro model is reliable for studying the biological activities of M1 and M2 macrophages and also for a proteomic approach. Proteomic techniques are useful for comparing the phenotype and behaviour of M1 and M2 macrophages during host pathogenicity. 2D gel electrophoresis is a powerful proteomic technique for mapping large numbers of proteins or polypeptides simultaneously. We describe the protocol of 2D electrophoresis using fluorescent dyes, named 2D Differential Gel Electrophoresis (DIGE). The M1 and M2 macrophages proteins are labelled with cyanine dyes before separation by isoelectric focusing, according to their isoelectric point in the first dimension, and their molecular mass, in the second dimension. Separated protein or polypeptidic spots are then used to detect differences in protein or polypeptide expression levels. The proteomic approaches described here allows the investigation of the macrophage protein changes associated with various disorders like host pathogenicity or microbial toxins. PMID:25408153
2D signature for detection and identification of drugs
NASA Astrophysics Data System (ADS)
Trofimov, Vyacheslav A.; Varentsova, Svetlana A.; Shen, Jingling; Zhang, Cunlin; Zhou, Qingli; Shi, Yulei
2011-06-01
The method of spectral dynamics analysis (SDA-method) is used for obtaining the2D THz signature of drugs. This signature is used for the detection and identification of drugs with similar Fourier spectra by transmitted THz signal. We discuss the efficiency of SDA method for the identification problem of pure methamphetamine (MA), methylenedioxyamphetamine (MDA), 3, 4-methylenedioxymethamphetamine (MDMA) and Ketamine.
2-D Imaging of Electron Temperature in Tokamak Plasmas
T. Munsat; E. Mazzucato; H. Park; C.W. Domier; M. Johnson; N.C. Luhmann Jr.; J. Wang; Z. Xia; I.G.J. Classen; A.J.H. Donne; M.J. van de Pol
2004-07-08
By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented.
On the sensitivity of the 2D electromagnetic invisibility cloak
NASA Astrophysics Data System (ADS)
Kaproulias, S.; Sigalas, M. M.
2012-10-01
A computational study of the sensitivity of the two dimensional (2D) electromagnetic invisibility cloaks is performed with the finite element method. A circular metallic object is covered with the cloak and the effects of absorption, gain and disorder are examined. Also the effect of covering the cloak with a thin dielectric layer is studied.
Rheological Properties of Quasi-2D Fluids in Microgravity
NASA Technical Reports Server (NTRS)
Stannarius, Ralf; Trittel, Torsten; Eremin, Alexey; Harth, Kirsten; Clark, Noel; Maclennan, Joseph; Glaser, Matthew; Park, Cheol; Hall, Nancy; Tin, Padetha
2015-01-01
In recent years, research on complex fluids and fluids in restricted geometries has attracted much attention in the scientific community. This can be attributed not only to the development of novel materials based on complex fluids but also to a variety of important physical phenomena which have barely been explored. One example is the behavior of membranes and thin fluid films, which can be described by two-dimensional (2D) rheology behavior that is quite different from 3D fluids. In this study, we have investigated the rheological properties of freely suspended films of a thermotropic liquid crystal in microgravity experiments. This model system mimics isotropic and anisotropic quasi 2D fluids [46]. We use inkjet printing technology to dispense small droplets (inclusions) onto the film surface. The motion of these inclusions provides information on the rheological properties of the films and allows the study of a variety of flow instabilities. Flat films have been investigated on a sub-orbital rocket flight and curved films (bubbles) have been studied in the ISS project OASIS. Microgravity is essential when the films are curved in order to avoid sedimentation. The experiments yield the mobility of the droplets in the films as well as the mutual mobility of pairs of particles. Experimental results will be presented for 2D-isotropic (smectic-A) and 2D-nematic (smectic-C) phases.
2D Fourier series representation of gravitational functionals in spherical coordinates
NASA Astrophysics Data System (ADS)
Ghobadi-Far, Khosro; Sharifi, Mohammad Ali; Sneeuw, Nico
2016-09-01
2D Fourier series representation of a scalar field like gravitational potential is conventionally derived by making use of the Fourier series of the Legendre functions in the spherical harmonic representation. This representation has been employed so far only in the case of a scalar field or the functionals that are related to it through a radial derivative. This paper provides a unified scheme to represent any gravitational functional in terms of spherical coordinates using a 2D Fourier series representation. The 2D Fourier series representation for each individual point is derived by transforming the spherical harmonics from the geocentric Earth-fixed frame to a rotated frame so that its equator coincides with the local meridian plane of that point. In the obtained formulation, each functional is linked to the potential in the spectral domain using a spectral transfer. We provide the spectral transfers of the first-, second- and third-order gradients of the gravitational potential in the local north-oriented reference frame and also those of some functionals of frequent use in the physical geodesy. The obtained representation is verified numerically. Moreover, spherical harmonic analysis of anisotropic functionals and contribution analysis of the third-order gradient tensor are provided as two numerical examples to show the power of the formulation. In conclusion, the 2D Fourier series representation on the sphere is generalized to functionals of the potential. In addition, the set of the spectral transfers can be considered as a pocket guide that provides the spectral characteristics of the functionals. Therefore, it extends the so-called Meissl scheme.
The NH2D hyperfine structure revealed by astrophysical observations
NASA Astrophysics Data System (ADS)
Daniel, F.; Coudert, L. H.; Punanova, A.; Harju, J.; Faure, A.; Roueff, E.; Sipilä, O.; Caselli, P.; Güsten, R.; Pon, A.; Pineda, J. E.
2016-02-01
Context. The 111-101 lines of ortho- and para-NH2D (o/p-NH2D) at 86 and 110 GHz, respectively, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure that is due to the nitrogen (14N) nucleus is resolved. To date, this splitting is the only one that is taken into account in the NH2D column density estimates. Aims: We investigate how including the hyperfine splitting caused by the deuterium (D) nucleus affects the analysis of the rotational lines of NH2D. Methods: We present 30 m IRAM observations of the above mentioned lines and APEX o/p-NH2D observations of the 101-000 lines at 333 GHz. The hyperfine patterns of the observed lines were calculated taking into account the splitting induced by the D nucleus. The analysis then relies on line lists that either neglect or include the splitting induced by the D nucleus. Results: The hyperfine spectra are first analyzed with a line list that only includes the hyperfine splitting that is due to the 14N nucleus. We find inconsistencies between the line widths of the 101-000 and 111-101 lines, the latter being larger by a factor of ~1.6 ± 0.3. Such a large difference is unexpected because the two sets of lines probably originate from the same region. We next employed a newly computed line list for the o/p-NH2D transitions where the hyperfine structure induced by both nitrogen and deuterium nuclei was included. With this new line list, the analysis of the previous spectra leads to compatible line widths. Conclusions: Neglecting the hyperfine structure caused by D leads to overestimating the line widths of the o/p-NH2D lines at 3 mm. The error for a cold molecular core is about 50%. This error propagates directly to the column density estimate. We therefore recommend to take the hyperfine splittings caused by both the 14N and D nuclei into account in any analysis that relies on these lines. Based on observations carried out with the IRAM
Stenman, Adam; Haglund, Felix; Clark, Victoria E.; Brown, Taylor C.; Baranoski, Jacob; Bilguvar, Kaya; Goh, Gerald; Welander, Jenny; Svahn, Fredrika; Rubinstein, Jill C.; Caramuta, Stefano; Yasuno, Katsuhito; Günel, Murat; Bäckdahl, Martin; Gimm, Oliver; Söderkvist, Peter; Prasad, Manju L.; Korah, Reju; Lifton, Richard P.
2015-01-01
As subsets of pheochromocytomas (PCCs) lack a defined molecular etiology, we sought to characterize the mutational landscape of PCCs to identify novel gene candidates involved in disease development. A discovery cohort of 15 PCCs wild type for mutations in PCC susceptibility genes underwent whole‐exome sequencing, and an additional 83 PCCs served as a verification cohort for targeted sequencing of candidate mutations. A low rate of nonsilent single nucleotide variants (SNVs) was detected (6.1/sample). Somatic HRAS and EPAS1 mutations were observed in one case each, whereas the remaining 13 cases did not exhibit variants in established PCC genes. SNVs aggregated in apoptosis‐related pathways, and mutations in COSMIC genes not previously reported in PCCs included ZAN, MITF, WDTC1, and CAMTA1. Two somatic mutations and one constitutional variant in the well‐established cancer gene lysine (K)‐specific methyltransferase 2D (KMT2D, MLL2) were discovered in one sample each, prompting KMT2D screening using focused exome‐sequencing in the verification cohort. An additional 11 PCCs displayed KMT2D variants, of which two were recurrent. In total, missense KMT2D variants were found in 14 (11 somatic, two constitutional, one undetermined) of 99 PCCs (14%). Five cases displayed somatic mutations in the functional FYR/SET domains of KMT2D, constituting 36% of all KMT2D‐mutated PCCs. KMT2D expression was upregulated in PCCs compared to normal adrenals, and KMT2D overexpression positively affected cell migration in a PCC cell line. We conclude that KMT2D represents a recurrently mutated gene with potential implication for PCC development. © 2015 The Authors. Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc. PMID:26032282
1α,25(OH)2D3 differentially regulates miRNA expression in human bladder cancer cells
Ma, Yingyu; Hu, Qiang; Luo, Wei; Pratt, Rachel N.; Glenn, Sean T.; Liu, Song; Trump, Donald L.; Johnson, Candace S.
2014-01-01
Bladder cancer is the fourth most commonly diagnosed cancer in men and eighth leading cause of cancer-related death in the US. Epidemiological and experimental studies strongly suggest a role for 1α,25(OH)2D3 in cancer prevention and treatment. The antitumor activities of 1α,25(OH)2D3 are mediated by the induction of cell cycle arrest, apoptosis, differentiation and the inhibition of angiogenesis and metastasis. MiRNAs play important regulatory roles in cancer development and progression. However, the role of 1α,25(OH)2D3 in the regulation of miRNA expression and the potential impact in bladder cancer has not been investigated. Therefore, we studied 1α,25(OH)2D3-regulated miRNA expression profiles in human bladder cancer cell line 253J and the highly tumorigenic and metastatic derivative line 253J-BV by miRNA qPCR panels. 253 J and 253J-BV cells express endogenous vitamin D receptor (VDR) which can be further induced by 1α,25(OH)2D3. VDR target gene 24-hydroxylase was induced by 1α,25(OH)2D3 in both cell lines, indicating functional 1α,25(OH)2D3 signaling. The miRNA qPCR panel assay results showed that 253J and 253J-BV cells have distinct miRNA expression profiles. Further, 1α,25(OH)2D3 differentially regulated miRNA expression profiles in 253J and 253 J-BV cells in a dynamic manner. Pathway analysis of the miRNA target genes revealed distinct patterns of contribution to the molecular functions and biological processes in the two cell lines. In conclusion, 1α,25(OH)2D3 differentially regulates the expression of miRNAs, which may contribute to distinct biological functions, in human bladder 253J and 253J-BV cells. PMID:25263658
Delivery of human NKG2D-IL-15 fusion gene by chitosan nanoparticles to enhance antitumor immunity
Yan, Chen; Jie, Leng; Yongqi, Wang; Weiming, Xiao; Juqun, Xi; Yanbing, Ding; Li, Qian; Xingyuan, Pan; Mingchun, Ji; Weijuan, Gong
2015-07-31
Nanoparticles are becoming promising carriers for gene delivery because of their high capacity in gene loading and low cell cytotoxicity. In this study, a chitosan-based nanoparticle encapsulated within a recombinant pcDNA3.1-dsNKG2D-IL-15 plasmid was generated. The fused dsNKG2D-IL-15 gene fragment consisted of double extracellular domains of NKG2D with IL-15 gene at downstream. The average diameter of the gene nanoparticles ranged from 200 nm to 400 nm, with mean zeta potential value of 53.8 ± 6.56 mV. The nanoparticles which were loaded with the dsNKG2D-IL-15 gene were uptaken by tumor cells with low cytotoxicity. Tumor cells pre-transfected by gene nanopartilces stimulated NK and T cells in vitro. Intramuscular injection of gene nanoparticles suppressed tumor growth and prolonged survival of tumor-bearing mice through activation of NK and CD8{sup +} T cells. Thus, chitosan-based nanoparticle delivery of dsNKG2D-IL-15 gene vaccine can be potentially used for tumor therapy. - Highlights: • Generation of a nanoparticle for delivery of dsNKG2D-IL-15 gene. • Characterization of the gene nanoparticle. • Antitumor activity mediated by the gene nanoparticle.
2D-2D tunneling field-effect transistors using WSe2/SnSe2 heterostructures
NASA Astrophysics Data System (ADS)
Roy, Tania; Tosun, Mahmut; Hettick, Mark; Ahn, Geun Ho; Hu, Chenming; Javey, Ali
2016-02-01
Two-dimensional materials present a versatile platform for developing steep transistors due to their uniform thickness and sharp band edges. We demonstrate 2D-2D tunneling in a WSe2/SnSe2 van der Waals vertical heterojunction device, where WSe2 is used as the gate controlled p-layer and SnSe2 is the degenerately n-type layer. The van der Waals gap facilitates the regulation of band alignment at the heterojunction, without the necessity of a tunneling barrier. ZrO2 is used as the gate dielectric, allowing the scaling of gate oxide to improve device subthreshold swing. Efficient gate control and clean interfaces yield a subthreshold swing of ˜100 mV/dec for >2 decades of drain current at room temperature, hitherto unobserved in 2D-2D tunneling devices. The subthreshold swing is independent of temperature, which is a clear signature of band-to-band tunneling at the heterojunction. A maximum switching ratio ION/IOFF of 107 is obtained. Negative differential resistance in the forward bias characteristics is observed at 77 K. This work bodes well for the possibilities of two-dimensional materials for the realization of energy-efficient future-generation electronics.
NASA Astrophysics Data System (ADS)
Movassaghi, Babak; Rasche, Volker; Viergever, Max A.; Niessen, Wiro J.
2004-05-01
For the diagnosis of ischemic heart disease, accurate quantitative analysis of the coronary arteries is important. In coronary angiography, a number of projections is acquired from which 3D models of the coronaries can be reconstructed. A signifcant limitation of the current 3D modeling procedures is the required user interaction for defining the centerlines of the vessel structures in the 2D projections. Currently, the 3D centerlines of the coronary tree structure are calculated based on the interactively determined centerlines in two projections. For every interactively selected centerline point in a first projection the corresponding point in a second projection has to be determined interactively by the user. The correspondence is obtained based on the epipolar-geometry. In this paper a method is proposed to retrieve all the information required for the modeling procedure, by the interactive determination of the 2D centerline-points in only one projection. For every determined 2D centerline-point the corresponding 3D centerline-point is calculated by the analysis of the 1D gray value functions of the corresponding epipolarlines in space for all available 2D projections. This information is then used to build a 3D representation of the coronary arteries using coronary modeling techniques. The approach is illustrated on the analysis of calibrated phantom and calibrated coronary projection data.
Evaluation of low-dose limits in 3D-2D rigid registration for surgical guidance
NASA Astrophysics Data System (ADS)
Uneri, A.; Wang, A. S.; Otake, Y.; Kleinszig, G.; Vogt, S.; Khanna, A. J.; Gallia, G. L.; Gokaslan, Z. L.; Siewerdsen, J. H.
2014-09-01
An algorithm for intensity-based 3D-2D registration of CT and C-arm fluoroscopy is evaluated for use in surgical guidance, specifically considering the low-dose limits of the fluoroscopic x-ray projections. The registration method is based on a framework using the covariance matrix adaptation evolution strategy (CMA-ES) to identify the 3D patient pose that maximizes the gradient information similarity metric. Registration performance was evaluated in an anthropomorphic head phantom emulating intracranial neurosurgery, using target registration error (TRE) to characterize accuracy and robustness in terms of 95% confidence upper bound in comparison to that of an infrared surgical tracking system. Three clinical scenarios were considered: (1) single-view image + guidance, wherein a single x-ray projection is used for visualization and 3D-2D guidance; (2) dual-view image + guidance, wherein one projection is acquired for visualization, combined with a second (lower-dose) projection acquired at a different C-arm angle for 3D-2D guidance; and (3) dual-view guidance, wherein both projections are acquired at low dose for the purpose of 3D-2D guidance alone (not visualization). In each case, registration accuracy was evaluated as a function of the entrance surface dose associated with the projection view(s). Results indicate that images acquired at a dose as low as 4 μGy (approximately one-tenth the dose of a typical fluoroscopic frame) were sufficient to provide TRE comparable or superior to that of conventional surgical tracking, allowing 3D-2D guidance at a level of dose that is at most 10% greater than conventional fluoroscopy (scenario #2) and potentially reducing the dose to approximately 20% of the level in a conventional fluoroscopically guided procedure (scenario #3).
Watanabe, Masamichi; Kudo, Yohei; Kawano, Mitsuko; Nakayama, Masafumi; Nakamura, Kyohei; Kameda, Mai; Ebara, Masamune; Sato, Takeki; Nakamura, Marina; Omine, Kaito; Kametani, Yoshie; Suzuki, Ryuji; Ogasawara, Kouetsu
2014-11-01
The natural killer group 2 membrane D (NKG2D) receptor is an NK-activating receptor that plays an important role in host defense against tumors and viral infections. Although the marmoset is an important and reliable animal model, especially for the study of human-specific viral infections, functional characterization of NKG2D on marmoset NK cells has not previously been conducted. In the present study, we investigated a subpopulation of marmoset NK cells that express NKG2D and exhibit cytolytic potential. On the basis of their CD16 and CD56 expression patterns, marmoset NK cells can be classified into three subpopulations: CD16(+) CD56(-), CD16(-) CD56(+) and CD16(-) CD56(-) cells. NKG2D expression on marmoset CD16(+) CD56(-) and CD16(-) CD56(+) splenocytes was confirmed using an NKG2D ligand composed of an MHC class I chain-related molecule A (MICA)-Fc fusion protein. When marmoset splenocytes were cultured with IL-2 for 4 days, NKG2D expression was retained on CD16(+) CD56(-) and CD16(-) CD56(+). In addition, CD16(+) CD56(+) cells within the marmoset NK population appeared which expressed NKG2D after IL-2 stimulation. IL-2-activated marmoset NK cells showed strong cytolytic activity against K562 target cells and target cells stably expressing MICA. Further, the cytolytic activity of marmoset splenocytes was significantly reduced after addition of MICA-Fc fusion protein. Thus, NKG2D functions as an activating receptor on marmoset NK cells that possesses cytotoxic potential, and phenotypic profiles of marmoset NK cell subpopulations are similar to those seen in humans. PMID:24860119
Interpretation of Magnetic Phase Anomalies over 2D Tabular Bodies
NASA Astrophysics Data System (ADS)
Subrahmanyam, M.
2016-05-01
In this study, phase angle (inverse tangent of the ratio of the horizontal to vertical gradients of magnetic anomalies) profile over two-dimensional tabular bodies has been subjected to detailed analysis for determining the source parameters. Distances between certain characteristic positions on this phase curve are related to the parameters of two-dimensional tabular magnetic sources. In this paper, I have derived the mathematical expressions for these relations. It has been demonstrated here that for locating the origin of the 2D tabular source, knowledge on the type of the model (contact, sheet, dyke, and fault) is not necessary. A procedure is evolved to determine the location, depth, width and magnetization angle of the 2D sources from the mathematical expressions. The method is tested on real field data. The effect of the overlapping bodies is also discussed with two synthetic examples. The interpretation technique is developed for contact, sheet, dike and inclined fault bodies.
2-D Magnetohydrodynamic Modeling of A Pulsed Plasma Thruster
NASA Technical Reports Server (NTRS)
Thio, Y. C. Francis; Cassibry, J. T.; Wu, S. T.; Rodgers, Stephen L. (Technical Monitor)
2002-01-01
Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) MK-1 pulsed plasma thruster. Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.